From Nuclein to the Double Helix -- The Scientists who Discovered DNA

Nucleotide pairing.jpg

DNA holds the key to all life as we know it.  From the smallest bacterium to the massive blue whale, deoxyribonucleic acid encodes the vast complexity of life through the unique arrangements of four simple nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G).  The difference between all species on the tree of life trace back to differing combinations of those four letters: A, T, C, and G.  The variation in these arrangements allows life on Earth to flourish in the deep oceans, dark jungles, blue skies, and every space in between.  Humans and chickens share 60% of their genes [1], humans and cats share 90% [2], and humans and chimpanzees share 96% of their entire DNA sequence [3].  The color of your hair, how tall you are, even whether or not you like cilantro, all are determined by the arrangements of DNA inherited from your parents.  However, for centuries, the hereditary material responsible for passing along these traits eluded scientist and philosophers alike. 

The human genome holds approximately 2.4 billion base pairs, yet only about 0.1% of that is estimated to provide all of the genetic variation between humans [4].  Great success is rarely achieved alone; often times it takes groups of people, each 0.1% different, to achieve the extraordinary.  Artists have their muses.  Composers have their orchestras.  Astronauts have Ground Control.  Scientists have their collaborators.  With 2018 marking the 65th anniversary of Watson and Crick’s discovery of the famous double helix structure of DNA, we should look back at the people and lessons involved in the quest to discover and characterize this most important of molecules.  James Watson and Francis Crick may be the most recognizable names associated with DNA research, yet many other scientists laid the groundwork for understanding DNA as we know it.  While there are far too many people and events to thoroughly catalogue, recounting the stories a few of the lesser known names can help us understand how scientists came to discover and characterize DNA, all while providing lessons that remain pertinent to this day.

MIESCHER, LEVENE, AND THE EARLY CHARACTERIZATION OF DNA

Friedrich Miescher was a Swiss ‘physiological chemist’ in the late 19th century.  In an era when many biological principles were being established, science was shifting from looking at whole organisms or systems towards focusing on their component molecules and cells.  Additionally, the concept of evolution and inheritance began garnering attention through the works of those such as Charles Darwin and Gregor Mendel.  Miescher was interested in finding the “fundamental principles of the life of cells” [5], and began investigating the composition of human white blood cells.  In 1866, while characterizing the composition of these cells, Miescher identified a substance that was neither protein nor lipid, rather something novel that he termed “nuclein”.  Overcoming technical limitations and carefully modifying experiments to suit this new substance, Miescher eventually isolated enough material for him to roughly characterize nuclein as a novel entity “not comparable to any hitherto known group” [5].  He was the first person to isolate what would soon become known as DNA.

 The four nucleotides of DNA. Image by Adam Greene.

The four nucleotides of DNA. Image by Adam Greene.

In the following years, Miescher eventually found nuclein to be within the sperm of many animals, from fish to frogs to bulls.  However, many remained skeptical of his work.  This was compounded by the fact that Miescher published only a few papers during his career, opting to discuss ideas through personal communications with friends, family, and colleagues.  Fortunately, due to his diligent note-taking and well-articulated protocols, others were able to confirm his finding within their own investigations, and eventually, nuclein was appreciated as a novel substance within cells.  Still, Miescher doubted that nuclein was hereditary material, believing it was too simple to provide the complex variation of life. 

Following the work of Miescher, many scientists sought to characterize the newly-named DNA. One such scientist was Phoebus Levene.  Born in what is now Lithuania, Levene was trained as a physician and chemist in Russia and New York.  However, he spent much of his time traveling to various institutions across the world to learn new techniques and study with different groups.  As a biochemist, Levene sought to understand the role of DNA within cells and understand the relationship of nucleic acid between organisms.  At the time he began DNA research, scientists understood little more than the rough chemical composition of nucleic acids.  By adapting to the technological limitations of the early 1900s, Levene established the empirical formula of nucleic acids (C38H50O29N15P4), and in 1929 identified the four base nucleotides of RNA: adenine, cytosine, guanine, and uracil (thymine in DNA was found shortly after) [6].  Unfortunately, Levene is probably best known as the founder of the tetranucleotide hypothesis, which suggested that nucleic acids were found in repeating cycle of subunits wherein all bases were equally represented.  While we now know that DNA varies greatly in length and nucleotide composition between species, at the time, the tetranucleotide hypothesis became ingrained in the field, stagnating interest and research into the functionality of DNA within the cell.  

DISCOVERING THE HEREDITARY NATURE OF DNA

 The Griffith Experiment which definitively showed that DNA was the hereditary material. Image by Adam Greene.

The Griffith Experiment which definitively showed that DNA was the hereditary material. Image by Adam Greene.

Early in the 1930s, scientists were still seeking to identify the hereditary material of life.  The tetranucleotide hypothesis presumed nucleotides could not encode the complexity of life, leading many to doubt the role of DNA in inheritance.  In 1928, Frederick Griffith sought to determine how two different morphologies of Streptococcus pneumoniae bacteria develop differing characteristics and understand how those traits affect disease [7].  Scientists understood that ‘smooth’ bacteria would lead to pneumonia and death in mice, while ‘rough’ shaped bacteria were harmless (nonvirulent).  Griffith co-infected mice with both live, nonvirulent bacteria and a heat-killed dose of virulent bacteria, expecting to recover only the non-virulent bacteria.  Surprisingly, co-infection caused pneumonia in mice from which live, virulent bacteria with the ‘smooth’ shape could be recovered [7,8].  From this experiment, Griffith determined that the nonvirulent bacteria must have taken up a “transforming principle”, acquiring virulence and morphological traits from the heat-killed ‘smooth’ bacteria.  Nonetheless, many continued to presume protein held the genetic information of cells and provided the “transforming principle”.  However, in 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty teamed together to isolate and characterize Griffith’s transformation principle.  Their findings left only one conclusion: DNA was the transforming principle.  Together, the works by Griffith and the Avery group discovered that DNA, not protein, encoded the traits that transferred between bacterial strains [9].  For the first time, scientists understood the role of DNA: storing the genetic information of life. 

Yet scientists didn’t fully grasp the importance of this finding.  Instead of celebrating discovering the molecular basis of life, the response was restrained, almost skeptical.  It seemed impractical for the vast complexity of life to be encoded by four simple nucleotides.  Proteins were more thoroughly investigated; they were much more varied in form and function, so it seemed logical that proteins comprised the hereditary information of life.  However, in 1952 Alfred Hershey and Martha Chase finally resolved any remaining doubt.  Using viruses that infect bacteria, Hershey and Chase were able to detect which viral components were required for self-replication.  Through careful isolation of protein and DNA, they were able to show that protein was unnecessary for viral replication; rather, the DNA was “injected” into the bacterium where it was copied and packaged into progeny virus [8-10].  Once and for all, scientists demonstrated that protein has no involvement in passing genetic information between generations.  DNA encodes the secrets to life.  Within a year of this finding, the work by Rosalind Franklin, Maurice Wilkins, James Watson, and Francis Crick revealed the structure of DNA and all the pieces of the puzzle were in place.  Only four years later, in 1957, Francis Crick established the central dogma, in which DNA is transcribed into RNA and subsequently translated into protein.  Finally, we understood the incredible importance of DNA.

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CONTEMPORARY LESSONS FROM HISTORICAL RESEARCH

Within 90 years, science had gone from identifying the novel, mysterious “nuclein” to understanding how DNA encodes the genetic information of life as we know it.  These discoveries did not just occur by accident.  They were the product of hard work and the circumstances surrounding these pioneering scientists.  Despite the technological limitations of the late 1800s, Friedrich Miescher was a rigorous investigator, diligently repeating his experiments and analyzing his conclusions.  Since he was a poor public communicator of his data, his rigorous note taking and experimental design allowed for others to repeat his works and champion their importance.  After all, research is critical to understanding how the world works.  It allows us to see how things truly are so that we may better understand and benefit from our surroundings.  So what good is knowledge if we do not share it for others to use?

Griffith, Avery, McCarty, and MacLeod all worked on the transforming principle of life, but each approached it from different perspectives.  Griffith was interested in the epidemiological implications for virulence transfer within Streptococcus strains, whereas the Avery group continued in his footsteps from a strictly biochemical point of view.  Together, their combined works were able to discover something incredible, that DNA alone can transfer traits between cells, leading to changes in shape and even the ability to cause disease.  Despite lingering skepticism , Hershey and Chase continued researching inheritance, conclusively showing that DNA is passed down from parental to progeny virus.  Individually, any one study incrementally improves our understanding of life; however, their stories together hold a sum greater than their parts.

Phoebus Levene traveled the world, inserting himself into different cultures and institutions.  This broad exposure allowed him to assimilate many cultural and scientific ideas into his work, helping him compose important questions leading to important findings.  His story also serves as a cautionary tale.  Incomplete information can be dangerous; not only does it leave out important details, but it can also serve to promote incorrect conclusions and halt future progress in uncovering the truth.  Today it remains critical that we seek out all of the available information and withhold judgement until all of the facts are known.  Too often we jump to the first and easiest conclusion, yet often the truth takes effort to discover.  The story of DNA beautifully demonstrates this.  It took a number of scientists rejecting assumptions.  It took cooperation, diligence, hard work, and dedication to finally understand how DNA shapes life as we know it.  Rarely does one person alone change the world.  Often, incredible accomplishments take many people with unique experiences and skills, each 0.1% genetically different, working together to accomplish something truly special.

 

 

References:

  1. National Institutes of Health, National Human Genome Research Institute. (2004, December 8). Researchers Compare Chicken, Human Genomes [Press release]. Retrieved from https://www.genome.gov/12514316/2004-release-researchers-compare-chicken-human-genomes/https://www.genome.gov/12514316/2004-release-researchers-compare-chicken-human-genomes/
  2.  Pontius JU, et al.; Agencourt Sequencing Team; NISC Comparative Sequencing Program (2007) Initial sequence and comparative analysis of the cat genome. Genome Res, 17: 1675–1689.
  3. National Institutes of Health, U.S. Department of Health and Human Services. (2005, August 31). New Genome Comparison Finds Chimps, Humans Very Similar at the DNA Level [Press release]. Retrieved from https://www.genome.gov/15515096/2005-release-new-genome-comparison-finds-chimps-humans-very-similar-at-dna-level/
  4. Genetics. (2018, January 04). Retrieved from http://humanorigins.si.edu/evidence/genetics
  5. Dahm, R. (2005) Friedrich Miescher and the discovery of DNA. Dev Biol, 278(2): 274-288.
  6. Hargittai, I. Struct Chem (2009) 20: 753. https://doi.org/10.1007/s11224-009-9497-x
  7. Méthot, PO. J Hist Biol (2016) 49: 311. https://doi.org/10.1007/s10739-015-9415-6
  8. Classic experiments: DNA as the genetic material. Retrieved from https://www.khanacademy.org/science/biology/dna-as-the-genetic-material/dna-discovery-and-structure/a/classic-experiments-dna-as-the-genetic-material
  9. Cobb, M. (2014). Oswald Avery, DNA, and the transformation of biology. Curr. Biol., 24, pp. R55-R60
  10. O'Connor, C. (2008) Isolating hereditary material: Frederick Griffith, Oswald Avery, Alfred Hershey, and Martha Chase. Nature Education 1(1):105

 

Footnote:

For a highly informative timeline of DNA discovery, check out “Friedrich Miescher and the discovery of DNA” by Ralf Dahm (reference 5). 

 

Biruté Galdika: The Champion of Orangutans

This post is an installment in our "Meet a Scientist" Series

A young girl, daughter of Lithuanian immigrants, worked her entire life to become a primatologist. She grew up to study orangutans in the depths of Indonesian forests and brought an unprecedented level of understanding to this elusive, at the time understudied, primate.

 Biruté Galdika. Photo courtesy of By Simon Fraser University - University Communications/Creative Commons.

Biruté Galdika. Photo courtesy of By Simon Fraser University - University Communications/Creative Commons.

This young woman was Biruté Galdikas. She was the third of paleontologist Dr. Louis Leakey’s famous primatologist mentees. Biruté is one of three women called the “Trimates,” three women studying primates, all trained by Leakey. The other two Trimates are Jane Goodall and Dian Fossey.  Despite being the least known of the three women, Galdikas made a significant mark on the world. What began as an interest sparked by a popular children’s book led Biruté to become a renowned expert and advocate for the endangered orangutan species.

 

A Curious Girl and a Curious George

Biruté Galdika was born at the end of World War II in Germany while her family traveled from Lithuania to Canada. As a little girl, Galdika settled on her career path by the time she was in second grade. Inspired by Curious George, she decided she would be an explorer and she followed that dream her entire life.

 Royce Hall, UCLA. Photo courtesy of Prayitno/Creative Commons.

Royce Hall, UCLA. Photo courtesy of Prayitno/Creative Commons.

She spent her childhood in Canada and even enrolled in and completed one year at the University of British Columbia before her family moved to the United States. At that point, she transferred to the University of California Los Angeles and studied zoology and psychology, finishing her studies in 1966. Three years later, she finished her Masters in anthropology and went on to complete her PhD.

Goodall and Fossey did not come from an academic zoology background, but instead met Leakey by chance during their first trips to Africa. Galdikas’ experience was different. She already knew about both Goodall and Fossey and their journeys. While Goodall and Fossey started their careers in the field, Galdikas’ went to school with hopes of following in their footsteps.

Galdika met Leakey while she was still in graduate school. One day, she approached her hero and expressed her interest in studying orangutans, hoping he would mentor her as he had for the other two women. Initially, he was not interested but she convinced him it was worth it. After 3 more years, Leakey managed to secure funding to support Birutés’ orangutan study and set her off on her journey to Indonesia.

Off to the Depths of the Indonesian Jungle

In 1971, at the age of 25 years old, Biruté Galdika, and her then husband, Ron Brindamour, moved to the Tanjung Puting Reserve in Indonesian Borneo. Many discouraged Biruté against this mission because they believed orangutans were too difficult to study. Unlike chimpanzees and gorillas, orangutans were more private, lived deep in swamp habitats and spent a great deal of time up high in the trees. Galdikas’ resolve, however, did not waiver.

 Tanjung Puting National Park, Central Kalimantan, Borneo. Photo courtesy of Nanosanchez/Creative Commons.

Tanjung Puting National Park, Central Kalimantan, Borneo. Photo courtesy of Nanosanchez/Creative Commons.

She and her husband set up Camp Leakey, their main site, named after her mentor. It began as merely two humble huts but over the years, grew into a large base. The Camp grew to become a world hub for orangutan research and rehabilitation. The camp ultimately trained dozens of students from Indonesia and North America to study orangutans.

When Biruté began, the world believed orangutans were antisocial. Galdikas proved this was not entirely accurate. She realized that young orangutans are actually fairly social but become more unsociable as they grew up. Only the adult males, she noticed, were really solitary. She also observed that some orangutan families migrated while others settle down in one location. She was the first to document the long interval between orangutan pregnancies, which is an impressive 7.7 years in Tanjung Puting. Watching their eating habits, she noted over 400 different foods incorporated into their diet. Biruté Galdikas’ 40 year study of orangutans in Tanjung Puting is historic, both because of the discoveries she made and because of its length. Her work constitutes the longest continuous study of one animal species conducted by one principle investigator.

 Orangutans. Photo courtesy of Bernard DUPONT from FRANCE/Creative Commons.

Orangutans. Photo courtesy of Bernard DUPONT from FRANCE/Creative Commons.

It was in Tanjung Puting that she also first met her second husband, Pak Bohap, a Dayak chief working at Camp Leakey. Though she was attracted to him right away, she initially avoided him because she was still married to her first husband. However, she and Brindamour divorced in 1979. Biruté and Brindamour had one child together, a son named Binti, who spent his childhood living with his parents in Indonesian Borneo, befriending orangutans. Unfortunately, since he did not have a chance to interact with children his own age, he began to act more and more like an orangutan, which worried his parents. They ultimately decided it was better for Binti to live with his father, away from camp. A few years later, Biruté married Pak and they had a daughter and son together.

A decade after she began, Biruté was deeply active in orangutan studies and conservation. In 1986, she and Pak founded the Orangutan Foundation International (OFI), based in Los Angeles. They also expanded their international efforts by working with others to organize sister organizations in Australia, Indonesia and the United Kingdom.

The Orangutan Foundation International

The goal of the Orangutan Foundation International (OFI) was to support the work that Galdikas and others conducted at Camp Leakey as part of the Orangutan Research and Conservation Project. Initially, Birutés’ mainly focused on local orangutans and forest conservation in Indonesia, where there were many battles to fight. Government officials often kept the primates as pets and both poachers and illegal loggers were common. Their original program worked with the Indonesian authorities to properly patrol Tanjung Puting National Park, rescue and rehabilitate captured orangutans and promote conservation efforts.

As Galdikas and her team continued to grow their efforts, they gained more international and mainstream attention. OFI helped promote and support these efforts on a wider scale. It not only spurred research and education efforts, but also conservation and forest protection. The goal was, and still is, to ensure the survival of biologically viable orangutans. Between the negative impact of humans on orangutan habitats and orangutans naturally long breeding intervals, the species was and still is on the brink of extinction.

Controversy

Despite the noble efforts of Camp Leakey, some controversy originally swirled around the institution in the 1970s and 1980s. In the beginning, the organization took in orphaned orangutans in attempts to rehabilitate them and then set them back into the wild. However, many worried that the program had some fatal flaws. Abandoned animals tended to be difficult to work with. This often placed staffers and guests of Camp Leakey in danger when orangutans lashed out.

In addition to safety concerns, others wondered if these rehabilitated orangutans would behave like their “wild” counterparts; what if their behavior was too different from their counterparts who rarely interacted with humans? Furthermore, animals in captivity could spread diseases into the native orangutan populations in the wild upon release. With all of these concerns clouding the rehabilitation efforts, the program was stopped. Now, ex-captive orangutans are rescued and brought to the Orangutan Care Center outside of Tanjung Putting.

With all of her conservation efforts and lobbying the Indonesian government to help protect parks and forests, Galdikas also made many enemies. She was harassed, threatened and even kidnapped by her opponents. None of this, however, stopped her fight.

The Professor, the Conservationist

 Riau palm oil concession. Photo courtesy of Hayden/Creative Commons.

Riau palm oil concession. Photo courtesy of Hayden/Creative Commons.

Unfortunately, even after Birutés’ 40 years of fighting for orangutans, the species is still in danger of extinction. Their habitats are still being destroyed. The primary enemy now are palm oil plantations surrounding the area. The plantations not only ruin the orangutans’ home but limit their ability to travel and migrate. General deforestation, hunting and illegal animal trading also contribute to the plight of this species.

Over the years, Biruté made great strides in trying to rescue these majestic creatures. In 1996, a special decree appointed her as senior advisor on orangutan issues to the Indonesian Mister of Forestry. The following year she won the Kalpararu Award. This is the highest honor bestowed for environmental efforts by Indonesia. The honor was even greater because Galdikas was the only non-Indonesian to win the award and was also one of the first women recipients. At the turn of the century, she gained Indonesian citizenship.

Over the span of her career, Galdikas published scientific articles, was on the cover of National Geographic, and wrote several books, including the memoir, Reflections of Eden in 1996 recounting her initial adventures from 1971 onward. More recently in 2011 she worked on the documentary, Born to Be Wild, that highlighted orphaned orangutans and elephants and the humans that work to save them.

These days, Biruté Galdikas spends half of her time in Indonesia and half in North America. She is a full professor at the Simon Fraser University in British Columbia and professor extraordinaire at the Universitas Nasional in Jakarta. All the while, she continues to push forth serious conservation efforts both in Indonesia and around the world. She rightfully argues that the orangutans are nowhere near being safe from extinction. As long as orangutans and other wild species are in danger, Biruté plans to continue to be their champion for change.

 

 

References:

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Dian Fossey: The Ultimate Friend of Mountain Gorillas

This post is an installment in our "Meet a Scientist" Series

Last fall, a baby gorilla in Rwanda was named Macibiri by the CEO of the Fossey Fund. Though Rwanda’s annual gorilla naming ceremony occurs each year, last year’s baby gorilla name was special. September 2017 marked the 50th anniversary of the Karisoke Research Center in Rwanda, Africa.

Macibiri was named after Dian Fossy, the primatologist and anthropologist, who established Karisoke and began what is now known as The Dian Fossey Gorilla Fund International. Little Macibiri is actually the granddaughter of a silverback leader, Titus, Fossey herself studied in the 70s. Her name came from Nyiramacibirim, Fossey’s nickname in the Kinyarwanda language. Fossey advanced gorilla research and conservation forward at a time when it was much needed. Her perseverance and passion led her to be one of the world’s most influential primatologists. Along with Jane Goodall (chimpanzees) and Biruté Galdikas (orangutans), these women together were known as the “Trimates.”

Fossey’s life and work is a study in contradictions. On one hand she paved the way for a better life for generations of gorillas like little Macibiri, promoted conservation, and persevered as a woman during a time people were openly hostile to women in science.  On the other hand, her actions towards poachers and other people in Rwanda ranged from unkind to criminal and horrifying. Ultimately her actions may have led to her murder. Learn more about both her life, her work and it’s legacy along with her darker side and actions.

 The Dian Fossey Gorilla Fund International in Rwanda. Photo Courtesy of Azurfrong/Creative Commons.  There are no known public domain images of Dian Fossey - but you can  see her image here .

The Dian Fossey Gorilla Fund International in Rwanda. Photo Courtesy of Azurfrong/Creative Commons.
There are no known public domain images of Dian Fossey - but you can see her image here.


Dian Fossey was born in 1932 in San Francisco, California. Though she loved animals from a young age, her path to becoming a primatologist took some twists. She initially followed in her stepfather’s footsteps and studied business at Marin Junior College. After her first year, she spent a summer on a ranch in Montana. This experience led her to switch from business to become a pre-veterinary student at the University of California. However, she switched again and ultimately graduated from San Jose State College with a degree in occupational therapy in 1954. After working with tuberculosis patients in California, Dian moved to Louisville, Kentucky to work as director of the occupational therapy department at Kosair Crippled Children’s Hospital.

It would take almost another 10 years before Dian made her way to Africa.

The Life Changing Decision

 Dr. Louis Leaky

Dr. Louis Leaky

Fossey always wanted to travel the world and go to Africa so when a friend returned from there after a vacation with pictures and stories, Dian knew it was her turn to travel. In 1963, she took out a bank loan along with her entire life savings and made her way to Africa. During this first trip, she traveled to Kenya, Tanzania, Congo and Zimbabwe.

One of her final stops on this excursion was the Olduvai Gorge in Tanzania, where she met Dr. Louise Leakey. He was a famous paleoanthropologist and archaeologist who demonstrated that humans evolved in Africa and promoted primate field research. Just a few years earlier, he supported Jane Goodall and her work with chimpanzees, which was only 3 years old at the time. Meeting Leakey was a major turning point in Fossey’s life. The second was meeting Joan and Alan Root in Uganda, close to the Virunga Mountains. They provided Dian with her first opportunity to witness the beautiful gorillas that would soon inspire her life work.

Dian eventually returned home back to a life as an occupational therapist, but as history now knows, this would not last long. Fossey published several articles and photographs from her Africa travels. A few years later, Leakey came through Louisville on a lecture tour. Dian eagerly spoke to him again after his lecture and left an impression. Leakey proposed Dian consider leading a long-term field project studying gorillas in Africa. Eight months later, he secured funds and in 1966, Dian Fossey headed back to Africa.

The Beginning of a Legacy

 Mount Mikeno. Photo courtesy of Cai Tjeenk Willink/Creative Commons.

Mount Mikeno. Photo courtesy of Cai Tjeenk Willink/Creative Commons.

As Dian headed back to Africa, Joan and Alan Root once again helped her along the way. She set up camp at Kabara, which lay close to Mt. Mikeno in the Democratic Republic of the Congo. There, she teamed up with an experienced gorilla tracker named Senwekwe who helped her find gorillas. Slowly, Fossey refined her ability to find and interact with gorillas. During this time, she managed to identify six gorilla groups in the area.

Unfortunately, the political situation in the Congo was harsh and in the middle of a civil war. In the summer of 1967, soldiers escorted her away from camp. They kept her in Rumangabo for two weeks until she escaped after bribing guards with cash to help her leave. What happened to her during this time is unclear, but accounts suggest she was abused. The U.S. Embassy warned her not to return but she ignored these warnings. She, with Dr. Leakey’s support, made plans to continue her work at a new site.

September 24, 1967, Dian Fossey established the Karisoke Research Center. 50 years later, this same center would be the home to Macibiri.

Karisoke Research Center

“Kari” – Mt. Karisimbi

“Soke” – Mt. Visoke

Dian set up the Karisoke Research Center in the Volcanoes National Park on the Rwandan side of the Virungas, in between Mt. Karisimbi and Mt. Visoke. Alyette DeMunck, a Belgian woman who was born and lived in the area, helped Dian find the site, communicate with the local people and became a close friend. As Dian began studying the gorillas in the area, she based her methods on those set by George Schaller. He wrote The Mountain Gorilla: Ecology and Behavior in which he highlighted the intelligence and beauty of gorillas. Fossey built off of his methods which involved “habituating” the animals to her presence, allowing her to observe them more closely. Fossey’s habituation process depended on the gorillas’ natural curiosity. She never bribed them to interact. She would “knuckle-walk” and chew celery to draw the animals near. She would mimic their vocalization. Her methods of gaining the gorillas’ trust were only part of her contribution to the field. She completely altered how the public saw gorillas.

Dian’s passion for the gorillas knew no bounds. Soon after she established Karisoke, she bonded with a 5 year old gorilla, aptly named Digit as he had a damaged finger on his right hand. Digit and Dian grew close. Digit was part of one of the groups Dian observed but he did not have playmates his own age. Dian herself was quite isolated and alone in her own studies. Tragically, on December 31, 1977, Digit died protecting his group from poachers.

The threats to mountain gorillas included poachers, environmental encroachment by humans and a lack of public sympathy for the animals, as they were perceived as violent and scary. Digit’s death made Dian realize that she needed to take action and bring attention to the plight of the gorillas. She began the Digit Fund to support “active conservation” and anti-poaching initiatives, which has now evolved into the Dian Fossey Gorilla Fund International. Dian wrote several pieces for National Geographic, including one about Digit’s death so that, for the first time, the public could see gorillas as Fossey saw them: as intelligent, social and complex individuals, not the monsters they were often portrayed to be. She shared their names, their personalities and dynamics; she humanized them just as Jane Goodall did with the chimpanzees.

Beyond Karisoke

Dian’s journey to becoming a primatologist was anything but linear. Even after years of field work, it bothered her that she did not have her doctorate. So, in 1970, she enrolled in Darwin College, Cambridge to study under Dr. Robert Hinde, who had also been Goodall’s mentor. Four years later, she walked away with a completed PhD. A few years later, Fossey eventually took time away from Karisoke to act as a visiting associate professor at Cornell University in 1980. She also began working on her manuscript, Gorillas in the Mist chronicling her time spent with mountain gorillas. The book was published in 1983 and a movie with the same title was released in 1988. Both were largely successful; the movie even gained Oscar recognition.

Dian Fossey’s Dark Side

Despite the positive awareness Dian induced, accounts of Fossey’s fight against poachers and efforts in “active conservation” describe aggressive and violent actions. Fossey feared that traditional, and potentially passive, long term goals would be useless and ultimately too late to save the dwindling mountain gorillas.

The death of the gorilla Digit at the hands of poachers led her to essentially declare war with the poachers, an effect with violent ramifications for both herself, the poachers, other locals and the gorillas. She often attacked and even killed the local’s cattle. She burned the homes of those she found guilty, fought and interrogated perpetrators, even bribing park rangers to help her. In the most horrifying story of her actions, she kidnapped the son of a poacher in retaliation for his alleged kidnapping of a baby gorilla. Poachers often targeted and killed gorillas that she was studying.

Though she did have human allies, as the years went on, an increasing number of accounts describe her personality as difficult and quite tortured. After years of largely isolated studies in the wild and a fire for aggressive conservation, many saw her as someone with far more compassion for gorillas than humans. To this day, many still wonder if and how this behavior contributed to her eventual murder.

A Tragic and Mysterious Ending

On December 27, 1985, just a few weeks before her birthday, Fossey was found dead in her cabin. Her head and face showed signs of attack by a machete. Theories still swirl around her murder yet to this day, no one has an answer. Though some people suspected robbery, none of her belongings appeared gone. She was buried at Karisoke, right next to Digit.

 Dian Fossey's Tombe. Photo courtesy of Zinkiol/Creative Commons.

Dian Fossey's Tombe. Photo courtesy of Zinkiol/Creative Commons.

Legacy

Dian Fossey devoted nearly 20 years of her life to the mountain gorillas and despite the violence done by her and to her, her legacy continues. The Dian Fossey Gorilla Fund International and the Karisoke Foundation continue to carry on Dian’s work and advocacy. In addition to continuing to protect the mountain gorillas in Rwanda, they expanded their conservation efforts to now protect Grauer’s gorillas in the Democratic Republic of Congo.

Macibiri is just one living example of Dian Fossey’s work, dedication and devotion the gorillas.

Dian Fossey is  not easy to write about. She challenges us to think about how we honor, or don’t honor, those who broke barriers and did amazing, outsized work, but whose personal behaviors were, at times, abhorrent. We can say, however, that we support efforts of protecting gorillas and the environment they live in, and we support efforts that take into account the needs of people living by these magnificent animals.

 

 

References:

Picture Credits:

 

Christmas Trees, Rocket Fuel, and Plastics: Terpenes in Nature and Engineering

When I think of the holiday season, the first thing that comes to mind is all the deep and inviting fragrances that this time of year brings. As we awaken from our Thanksgiving feast-induced stupors, we undoubtedly will be bombarded with the smells of the holiday season for the next 30 days – smells that will trigger memories of holidays past, like warm cookies fresh out of the oven, the rich spices in mulled wine and ciders, and the best smell of all to an outdoor enthusiast like me, the crisp and clean scent of Christmas trees.

The Smell Of Christmas Is In the Air… and bark!

Christmas Tree.jpg

Christmas trees are an evergreen conifer, a type of tree that includes spruce, pine, and fir. Have you ever wondered what gives Christmas trees their signature scent? The answer is a mix of chemicals called terpenes. Terpenes are in the sticky resin substance exuded by these conifers. Terpenes are a class of molecules that give off the sharp and sweet Christmas tree scent. When the tree bark is damaged, such as when the tree is cut down to be sold, the resin flows out of the bark. In nature, the layer of resin hardens to protect the damaged area of the bark. The terpenes in the resin inhibit the growth of fungi and also deter herbivores, notably the bark beetle, which otherwise would feed on the tree.

Terpenes are also released into the air. If you’ve ever been to or seen pictures of pine forests and mountains, you might have noticed a hazy, blue aura and clouds above the trees. Scientists believe that the terpenes released by the trees into the atmosphere react with the air to collect moisture and form clouds in order to protect the trees from harsh sunlight and to keep the forest cool. Terpenes are what make the Smoky Mountains smoky!

 Smoky Mountains National Park

Smoky Mountains National Park

The principal molecule that gives the earthy pine smell to the trees is called pinene. Pinene has two different forms called alpha-pinene and beta-pinene. These two molecules are mirror images of each other,* and beta-pinene is what provides the woody fragrance we associate with pine trees. Both forms of pinene are very flammable and are the reason Christmas trees and pine cones burn easily. This is also why forest fires can spread so quickly. At room temperature, pinene molecules are volatile and evaporate, fortunately, is which is why we are able to smell them so strongly in our homes!

Different species of conifers have distinct smells due to different mixtures of various molecules. For example, bornyl acetate, also called heart of pine, gives off the rich depth of pine scent and is found in pine and fir trees.** This is the compound that is commonly used to make pine fragrances you see sold in stores. Both balsam firs and silver pines (two species of conifers used for Christmas trees) are rich in bornyl acetate. Other molecule compounds that give off distinctive scents include limonene (a citrus scent), camphene (a camphor aroma), and alpha-phelladrene (a minty and citrus-y fragrance).

So now we know that terpenes are made by conifers to protect themselves from other organisms, and they happen to confer that refreshing scent that many of us bring into our homes in December. But, did you know that many non-fragrant consumer products are made with terpenes as well?

Other uses for terpenes

You may guess correctly that the most widely used product made from terpenes bears its name – turpentine. Turpentine is a solvent that is used as a paint thinner. Terpenes are also used in medicine as an anesthetic and even in anti-malarial and anti-cancer treatments. Additionally, plant-derived compounds have been the focus for a more sustainable future. Many scientists and engineers in the past couple of decades have concentrated their efforts to develop processes that might allow terpenes to replace petroleum in both the fuels and plastics industries.

Terpenes and Energy

  E. coli  bacteria - the strain of bacteria genetically engineered to produce terpene. 

E. coli bacteria - the strain of bacteria genetically engineered to produce terpene. 

Chemically, terpenes and petroleum are related because both are mixtures of compounds called hydrocarbons, or molecules composed only of hydrogen and carbon. Although the chemical structures of the compounds are different, scientists are familiar with the processes and procedures needed to manipulate hydrocarbons into useful molecules.  The benefit of using terpenes instead of petroleum is that they are a renewable resource, reducing our dependence on fossil fuels and thus our impact on the environment.

Terpenes are generated in large amounts as a waste product by the lumbering industry, but unfortunately, conifers do not produce enough terpenes to sustain a fuel industry. Two tons of wood chips only provide 4 kilograms (8.8 lbs) of crude turpentine. To address this, scientists are exploring the potential of genetically engineering bacteria to produce these compounds. To this end, a research group at the University of California, Berkeley has created a strain of bacteria that can convert sugar into terpenes, showing that these genetically modified bacteria may be a sustainable source of terpenes in a process that is analogous to brewers using yeast to make beer.

Research conducted in the Navy in the last decade found that two molecules of the pinene joined together has very similar properties to JP-10, a rocket fuel that is widely used in commercial and military launches. This researched has inspired biochemistry researchers to pursue pinene as a cheaper and sustainable fuel. In 2014, a laboratory at the Georgia Institute of Technology created a bacteria strain that produces pinene in the hopes of providing an alternative fuel source. Efforts now in this field are aimed at scaling up pinene production to be efficient and cheap enough to be viable in the fuel industry.

Making Plastics More Sustainable

 Plastic pollution often accumulates on beaches. 

Plastic pollution often accumulates on beaches. 

Another environmental issue being addressed with terpenes is the plastics industry. The large amount of plastic being created and disposed of is filling our landfills and oceans, and entire islands composed entirely of this garbage have been found in the Pacific Ocean. It is amazing and sad to think that almost every piece of plastic that has ever been produced is still in existence because the vast majority of plastics are not biodegradable. Furthermore, the process of creating these plastics requires petroleum. Even biodegradable plastics made from corn or sugar cane require some form of crude oil to manufacture. A research group at the University of Bath is investigating the use of pinene as an alternative to oil to produce these biodegradable plastics, as these polyesters (the main component of plastics) combined with pinene can create a flexible and strong material, completely circumventing the use of fossil fuels. Given the staggering amounts of plastic being created every day, even eliminating just the need for fossil fuels would have a large impact.

 

Christmas trees throughout history have come to be a symbol of life and hope, staying green through the entire winter and reminding people of the spring to come. Perhaps this year when you take a deep breath and savor that sharp and sweet pine scent, you will have a new appreciation for these trees. These trees are no longer only a symbol of hope, but the very chemical compounds that it produces could be the key to a sustainable and more environmentally conscious future for us all.

 

*Molecules that are non-superimposable mirror images of each other are called enantiomers.  

**Bornyl acetate belongs to a class of compounds called esters. Esters are found in fruits and are known and used for their pleasant smells.

 

References:

·      “The Aroma of Christmas Trees.” Compound Interest, 19 December 2014. http://www.compoundchem.com/2014/12/19/christmastrees/. 24 November 2017.

·      “Bacteria could be rich source for making terpenes.” News from Brown. Brown University, 22 December 2014. https://news.brown.edu/articles/2014/12/terpenes. 24 November 2017.

·      Conners, Deanna. “Why pine trees smell so good.” Earth. EarthSky, 22 December 2016. http://earthsky.org/earth/why-conifer-christmas-trees-pine-spruce-fir-smell-terpenes. 23 November 2017.

·      Helmenstine, Anne Marie. “Why Christmas Trees Smell So Good: Chemistry of the Christmas Tree Aroma.” Science, Tech, Math. ThoughtCo. https://www.thoughtco.com/why-christmas-trees-smell-so-good-606134. 24 November 2017.

·      Howgego, Josh. “Terpenes: not just for Christmas.” Education in Chemistry. Royal Society of Chemistry, 1 January 2014. https://eic.rsc.org/feature/terpenes-not-just-for-christmas/2000116.article. 23 November 2017.

·      Kirby, James, et al. “Enhancing Terpene Yield from Sugars via Novel Routes to 1-Deoxy-D-Xylulose 5-Phosphate.” Applied and Environmental Microbiology 81(1): 130-138 (2015).

·      Romuld, Maggie. “That Christmas Tree Smell Just Got a Lot More Interesting.” Nature. The Science Explorer, 5 January 2017. http://thescienceexplorer.com/nature/christmas-tree-smell-just-got-lot-more-interesting. 23 November 2017.

·      Quilter, Helena C., et al. “Polymerisation of a terpene-derived lactone: a bio-based alternative to ε-caprolactone.” Polymer Chemistry, 8: 883 (2017).

·      Sarria, Stephen, et al. “Microbial Synthesis of Pinene.” ACS Synthetic Biology, 3(7): 466-475 (2014).

·      Vance, Erik. “Atmospheric chemistry: The man who smells forests.” Nature 459: 498-499 (2009).

Images:
All images used were found on Wikimedia Commons and are Public Domain
.

Worms and Flies and Fishies (and MORE), Oh My!

When we think of scientists, thoughts of lab mice are close behind (à la Pinky and the Brain) but did you know that scientists use many OTHER organisms to study both basic and biomedical sciences? Just imagine: biomedical research using fruit flies could relate directly back to you, who, relative to a fruit fly, are much larger and seemingly more complex!

 Black sea urchin. Photo courtesy of Lacen/Public Domain.

Black sea urchin. Photo courtesy of Lacen/Public Domain.

Model organisms are any non-human species that scientists use to understand complex biological processes. Good model organisms are easy to breed, have short life cycles and are often physically small, making them easy to maintain in laboratories and manipulate in experiments. Outside of rodents, common model organisms include, but are not limited to: fruit flies (Drosophila melanogaster), nematode worms (C.elegans), yeast (Saccharomyces cerevisia), zebrafish (Danio rerio), and sea urchins (Arbacia).

As expected, model organisms are great at being, well…models. So, it may be hard to imagine how they can be used to understand human health. However, believe it or not, these organisms are great at doing just that! Despite looking dramatically different from humans, many of the key genes in model organisms have gene counterparts (homologs) in humans and other large mammals. This is why fruit flies are useful to scientists study cleft palate and the mechanisms behind diabetes…though more about that later. First, it is important to understand that non-rodent organisms are a hallmark of scientific research and that their influence on scientific progress cannot be overlooked. Some of these species have even earned scientists Nobel Prizes.

Major biological advances via some unexpected organisms

To grow and develop, organisms need to make new cells from older cells. How does this process work? And how do organisms get rid of these old cells or cells that are “bad”? Using model organisms like yeast and sea urchins, scientists answered these fundamental questions (by discovering the mechanisms behind the cell cycle and apoptosis, respectively) and as a result, expanded our understanding of diseases like cancer at the same time. Yes, sea urchins, like the ones you see at the aquarium, can help us fight cancer!

  Saccharomyces cerevisiae. Photo courtesy of Masur/Public Domain.

Saccharomyces cerevisiae. Photo courtesy of Masur/Public Domain.

In 2001, three scientists won the Nobel Prize for discovering key proteins important in a molecular process called the cell cycle using yeast and sea urchins. The cell cycle is the process by which cells make more cells. They do this through duplication and division of their genetic material and cell growth; it is a highly regulated process. Since cells are the basic building blocks of all living organisms, scientists were lucky to find the ideal model organisms to dissect this mechanism. The first model organism used, yeast, are single-celled, simple eukaryotic organisms whose genome can be easily manipulated, making them popular for genetic studies. They are also inexpensive and easy to grow in lab. Picture Erlenmeyer flasks full of yeast! Sea urchins, the other system used, have eggs that can be harvested and fertilized outside of the animal and, when initiated, divide synchronously, making cell division and development easy to visualize. Using these organisms, the Nobel Prize-winning research discovered several principle cell cycle proteins called cyclins and cyclin dependent kinases (CDKs).

Excitingly, these findings about the cell cycle not only developed our basic understanding of cells but set a foundation from which scientists could better understand disease. Cancer is characterized by a lack of cell cycle regulation. Tumors are the result of acquired genetic mutations and uncontrolled cell growth. Yeast and sea urchins, which appear so different from us, enabled scientists to understand fundamental biological processes yet also also provided mechanisms to target in cancer research and treatment. As startling as it may sound, this was not the only time model organisms helped scientists make landmark, prize-winning discoveries. It has occurred countless times throughout science history!

 C.elegan worms. Photo courtesy of ZEISS Microscopy Germany/Creative Commons.

C.elegan worms. Photo courtesy of ZEISS Microscopy Germany/Creative Commons.

The following year, 2002, three more scientists won the Nobel Prize for their work developing “nematode worms” (C.elegans) as a model organism and using them to study a process scientists call “programmed cell death” or more technically speaking, apoptosis. This is like it sounds. Cells are programmed to self-destruct and this apoptosis is a necessary part of healthy development. Like the cell cycle, understanding apoptosis also improved our understanding of human health. One of the major advantages of C.elegans is that scientists can actually track each individual cell during a worm's development under a microscope. Utilizing the uniqueness of this organisms, scientists observed that the same 131 cells of the total 1090 cells in a developing worm consistently died, indicating that apoptosis was a natural and necessary process and this, in part, led to the identification of apoptosis genes. Apoptosis is evolutionary conserved in other organisms and defects in the process can cause human diseases. It is often triggered when healthy cells detect something wrong. In diseases like cancer, mutations in apoptosis genes allow unhealthy and dysfunctional cells to continue growing. Conversely, an increase in cell death of specific cell types contribute to some neurodegenerative diseases such as Alzheimer’s and Huntington’s Disease.

They are more like us (humans) than you would Think!

Hopefully it is now clear that non-rodent model organisms are crucial tools used by scientists to dissect basic biological processes, but don’t forget - these organisms can also more directly model human health. Just like with mice, there are a lot of genes in these other organisms that have homologs in humans, making them also great for modeling diseases and drug development.

 Drosophila melanogaster (fruit fly). Photo courtesy of André Karwath aka AKA/Creative Commons.

Drosophila melanogaster (fruit fly). Photo courtesy of André Karwath aka AKA/Creative Commons.

For instance, in 1980, scientists discovered the hedgehog gene (hh) which is necessary for Drosophila (fruit fly) body patterning. Soon after, scientists found three similar genes in humans. One of these genes, sonic hedgehog (shh) – yes, it is named after the video game – is also important in early human development. Defects in human shh can result in cleft palate birth defects, which occur in 1 of every 1000 newborns. Scientists are therefore using flies to better understand the underlying mechanisms of cleft palate defects and using these studies to guide future research in larger mammals.

Now these same flies are also helping scientists understand the mechanisms behind diabetes. Despite being different from humans, insulin affects humans and flies similarly. In humans, insulin regulates the ability of cells to absorb glucose from the blood. In diabetes, this process is blocked. When scientists mutated several insulin-like genes in fruit flies, the insects developed diabetic symptoms and preliminary studies suggested that the cellular reason for their symptoms could be similar to those in humans. The hope is to use these fly models to create drugs and treatments that target these commonalities between flies and humans to ultimately combat diabetes.

Of course, as with any model, each system has its limitations, but the importance of using model organisms is clearly not a thing of the past. Studying model organisms and using the information we gain from them serve as the basis of many medical advances. Plus remember: some of the most seminal science discoveries that fill our textbooks were done in these species! Science is an abyss of unknown and model organisms have been, and will continue to be, a vital tool in discovery. Though these studies can stand alone, they also set a foundation for future studies in larger mammals (humans), saving scientists and society time, energy and money.

So the next time you see a fruit fly buzzing around your house, as annoying as it may seem, keep in mind that the species helped make countless scientific breakthroughs.

 

 

References:

Picture Credits:

Ocean Acidification & Its Impacts

 Beach in Oahu, Hawaii

Beach in Oahu, Hawaii

With warm weather and summer vacation just around the corner, it is difficult to escape the draw of our oceans and beaches. Almost all of us, especially here in San Diego and other beachside cities, have stories to tell about our oceans, whether it is a fond memory from a family trip to the beach, a fishing voyage with friends, or a solo surf session by a pier at sunset. However, the oceans also tell us stories, and the narrative becoming clearer and more imminent is that of the declining health of our oceans.

  A factory in China . The Industrial Revolution brought about a reliance on burning fossil fuels for energy, which pumps large amounts of carbon dioxide and pollutants into our environment.

A factory in China. The Industrial Revolution brought about a reliance on burning fossil fuels for energy, which pumps large amounts of carbon dioxide and pollutants into our environment.

Since the Industrial Revolution, the use of fossil fuel-powered machinery has emitted billions of tons of carbon dioxide along with other gases into our atmosphere. Today, it is estimated that one million tons of carbon dioxide are emitted every hour – that’s a faster rate than has existed on our planet in tens of millions of years. Our oceans and seas absorb up to one-third of these gas emissions. This helps all of us on land because these greenhouse gases are taken out of the atmosphere, slowing down climate change. But, still, this comes at a cost.  

All solutions are acids or bases, and the acidity or basicity of a solution is defined by its pH value. A pH of 7 is neutral - the pH of pure water. Above pH 7 is basic, and below pH 7 is acidic. The surfaces of our oceans are healthiest when they are slightly basic with a pH of 8.2. Because of the large amounts of carbon dioxide entering our atmosphere, the pH of our oceans is decreasing, which is a process called ocean acidification.

 A scientist in Svalbard, Norway studying the effects of climate change on the oceans' chemistry. 

A scientist in Svalbard, Norway studying the effects of climate change on the oceans' chemistry. 

Because of ocean acidifications, our oceans are now at pH 8.1, and at the current rate, the ocean’s pH is predicted to drop about 0.5 pH units before the end of the century! At a glance, this may seem like a small or insignificant change, but it is enough to cause very serious problems in biological systems. For example, human blood is normally between a pH of 7.35 and 7.45. A drop in pH of 0.2-0.3 can cause seizures, comas, and death. You can imagine the large impact such a change can have on an ecosystem that takes up over 70% of our planet! About 250 million years ago, large levels of volcanic activity caused a similar level of ocean acidification, and this change contributed to the death of 90% of marine species.

So, how does ocean acidification occur? Carbon dioxide in our atmosphere dissolves in water to make a molecule called carbonic acid, so as our oceans continue to absorb carbon dioxide, the waters become increasingly acidic. In the past, basic molecules created by weathering rocks and sediments were enough to balance the carbonic acid and keep the oceans at their ideal 8.2 pH. However, rock erosion is not fast enough to keep up with acidification caused by an increasing excess of carbon dioxide released into our atmosphere.

 An experiment showing how acidic waters dissolve marine organisms' shells.

An experiment showing how acidic waters dissolve marine organisms' shells.

Such a rapid change in our oceans’ chemistry is not compatible with our marine organisms, which have evolved over millions of years in an ocean with a stable pH of 8.2. Ocean acidification affects marine organisms’ ability to communicate, reproduce, and grow. For example, at a healthy pH, about 10% of the carbon dioxide dissolved in the water exists as a molecule called carbonate. To make their shells, marine organisms like corals, clams, mussels, and oysters combine calcium with carbonate. Acidic waters have less carbonate, making it difficult for these animals to survive. Furthermore, acidic waters can chemically change the carbonate in the organisms’ shells to slowly dissolve them.

Acidic waters also lower the pH of the body fluids in all marine life, such as fishes, making it difficult for them to breathe and for their brains to function. It’s similar to if the air we breathe changed. If you have ever been at high elevation in the mountains where there is less oxygen in the air, you might have had a similar experience with difficulties breathing or headaches.

 Coral reefs in the Red Sea

Coral reefs in the Red Sea

In addition to harming marine life, ocean acidification is hurting certain industries, creating economic stress. There is a decline in commercial fisheries, especially those that trade in lobster, scallops, and other shellfish. California, which is home to 31 different kinds of salmon and trout, is predicted to lose 23 of these species within the next century. More gravely, in many fishing villages in Indonesia, The Philippines, and Malaysia, fishing is necessary for survival. Hundreds of communities like these around the world must fish to feed themselves, so the depletion of their food source is a serious issue.

Fortunately, ocean acidification is a somewhat gradual process, giving us time to recognize the impact of human activity and change our behaviors to lessen harmful disruption to our oceans. To lower your own individual carbon dioxide emissions (or “carbon footprint”), you can use less electricity, recycle, and reducing use of your car by biking, walking, or using public transportation instead. If you want to find out your carbon footprint, you can visit The Nature Conservancy’s calculator here. More powerful ways to help the oceans are to support political measures that combat increasing carbon emissions and to donate to or volunteer with local organizations that champion environmental causes. One example is the Surfrider Foundation - an international organization that promotes the health of our oceans and beaches. 

 Fishermen in Pangadaran, Indonesia

Fishermen in Pangadaran, Indonesia

Carbon dioxide is estimated to exist in the atmosphere for hundreds of years, so even if we cut off all carbon emissions today, we will not see a reversal of ocean acidification immediately. By teaching all of our friends and family about how we affect our environment, and by encouraging everyone to reduce our carbon footprints, we can thank our oceans for all that they give to us and ensure that our beautiful oceans and all of its organisms will exist in the future.

 

For another informative post about ocean acidification, check out John Hawthorne's article https://moboxmarine.com/blog/oceans-are-getting-acidic/

 

References

·      Bland, Alistair. “Many Of California’s Salmon Populations Unlikely To Survive The Century.”  The Salt. NPR, 17 May 2017. http://www.npr.org/sections/thesalt/2017/05/17/528826774/many-of-california-s-salmon-populations-unlikely-to-survive-the-century. 19 May 2017.

·      Brewer, Peter G. and James Barry. “Rising Acidity in the Ocean: The Other CO2 Problem.” Sustainability. Scientific American, 1 September 2008. https://www.scientificamerican.com/article/rising-acidity-in-the-ocean/. 17 May 2017.

·       “Ocean Acidification.” Pristine Seas. National Geographic. http://ocean.nationalgeographic.com/ocean/explore/pristine-seas/critical-issues-ocean-acidification/. 18 May 2017.

·      “Ocean Acidification.” The Ocean Portal Team and Jennifer Bennett. Ocean Portal. Smithsonian National Museum of Natural History. http://ocean.si.edu/ocean-acidification. 18 May 2017.

·       “Ocean Acidification.” Know Your Ocean. Woods Hole Oceanographic Institute. http://www.whoi.edu/ocean-acidification/. 16 May 2017.

Images:
All images used were found on Wikimedia Commons and are Public Domain

The Extraordinary Life and Work of George Washington Carver

This post is the first installment of our "Meet a Scientist" Series

  George Washington Carver in 1910

George Washington Carver in 1910

Meet George Washington Carver – scientist, agriculturist, scholar, inventor, but, contrary to popular belief, not the inventor of peanut butter.  Although none of his hundreds of peanut products achieved commercial success, Carver’s accomplishments have landed him an irreplaceable part in history for revolutionizing agriculture in the United States and overcoming seemingly insurmountable obstacles to become a highly esteemed, African-American faculty member of the Tuskegee Institute in a time of extreme racial tensions.

George Washington Carver was born into slavery in Missouri to Mary and Giles, a slave couple owned by Moses and Susan Carver. The exact date of his birth is unknown, but it is estimated to be in the mid-1860s. Sadly, at approximately one-week old, George, his mother, and sister were kidnapped by farm raiders to be sold in Kentucky. George was located and returned to Moses Carver’s farm, but his mother and sister were not found.

  George Washington Carver at work

George Washington Carver at work

Moses and Susan Carver decided to keep and raise George and his brother. Because no schools accepted black students, Susan taught them to read and write at home. George valued learning from a young age, and enrolled in a school for black children about ten miles from the Carver Farm. When he enrolled, instead of continuing to be referred to as “Carver’s George,” he adopted the name “George Carver.” George pursued his education and graduated from high school in Kansas, but was denied admission to Highland College because of his race.

George enrolled in the botany program at the Iowa State Agricultural College as the first black student at the school. He graduated with a Bachelor of Science degree and, in 1896, a master’s degree, establishing himself as an exceptional botanist in the process. In 1896, Booker T. Washington, president of the Tuskegee Institute in Alabama, took notice of George Carver’s outstanding accomplishments and hired him as the head of the institute’s agricultural department. Carver’s research and work focused heavily on creating alternative uses of common crops, especially the peanut and sweet potato. He developed products from these plants for a myriad of purposes (over 300 products from peanuts and over 100 products from sweet potatoes!), such as paints, plastics, flours, shaving cream, glue, and even a form of gasoline. He is mistakenly commonly credited with the invention of peanut butter, but in reality, peanut butter made from ground peanuts date as far back as the 15th century by the Aztecs and Incas – centuries before Carver was even born.

  George Washington Carver Museum

George Washington Carver Museum

Carver remained adamantly passionate about education. Due to his very humble beginnings, he spent his entire life helping poor farmers, especially African-Americans, improve their crops and get out of poverty, always refusing compensation for his advice. Carver promoted various methods of crop rotation, which is a large part of why peanuts became a large source of his innovations. He promoted the growing of crops that fixed nitrogen, promoting sustainability of nutritious soil and, therefore, healthy crops. Carver lived frugally and used his fame to promote scientific causes. He also started a mobile classroom known as the “Jesup wagon” that visited various farms to educate the farmers about agricultural techniques. He wrote for a newspaper column and traveled around the country, speaking about the importance of agricultural research and innovation. For ten years in 1923-1933, he spoke in support of racial harmony when he visited white colleges in the South for the Commission on Interracial Cooperation and the YMCA. Although he never spoke out directly against racist social and economic injustices of the time, his scientific success and open-minded demeanor still earned him great respect and admiration from both African-American and Caucasian people.

George Carver became so well-known for his work that president Franklin Delano Roosevelt looked to him for advice on agricultural matters. In 1916, Carver became a member of the British Royal Society of Arts, which is a very rare honor given to Americans.

  1942

1942

George Washington Carver passed away in 1943 at the age of 78. He is buried next to his friend and colleague Booker T. Washington. President Franklin D. Roosevelt dedicated $30,000 for a monument to be constructed in Carver’s honor, located west of his hometown of Diamond, Missouri. This is the first national monument dedicated to an African-American. Carver’s epitaph summarizes his beliefs and the humble philosophy by which he lived his life: “He could have added fortune to the fame, but caring for neither, he found happiness and honor in being helpful to the world.” To this day, he remains an icon of African-American achievement, scientific achievement, and the transformative power of education.

 

 

Sources:

“George Washington Carver Biography.com.” Biography.com Editors. The Biography.com website. http://www.biography.com/people/george-washington-carver-9240299. September 28, 2016. A&E Television Networks. April 26, 2017.

“Who Invented Peanut Butter?” National Peanut Board. http://nationalpeanutboard.org/peanut-info/who-invented-peanut-butter.htm. April 26, 2017.

“Major Contributions – George Washington Carver.” https://sites.google.com/site/georgewashingtoncarverbiotech/.  George Washington Carver Biotech. April 25, 2017.

“George Washington Carver.” Linda O. McMurry. The Reader’s Companion to American History. 1991. http://www.history.com/topics/black-history/george-washington-carver. April 25, 2017.

Images:
All images used were found on Wikimedia Commons and are Public Domain

The Colorful Chemistry Behind an Eggscellent Easter

It’s that time of year when we can’t walk into a store without seeing displays of chocolate bunnies, marshmallow chicks, and vibrant bouquets of flowers. Along with all these springtime treats, perhaps the most memorable and engaging tradition (and my personal favorite) is the dyeing of Easter eggs.

By Superbass - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=31904555

Decorating eggs is a deeply rooted, international tradition. The oldest examples of this activity are the engraved ostrich eggs found in Africa 60,000 years ago. Eggs across many countries and cultures are celebrated, and whether these activities are based on religion or the coming of spring, eggs represent rebirth and life.

For those who have participated in egg dyeing, you may have wondered: Why is vinegar added to the dye solution? This can be explained through simple chemistry. You've probably heard of acids and bases - it turns out that all solutions have a degree of acidity or basicity. Acids chemically react with bases to create solutions that are more neutral – that is, closer to pure water.

 lkonact via wikimedia commons

lkonact via wikimedia commons

So, back to the initial question – why is vinegar needed to dye an egg? The answer is that most egg dyes need acid to bind the dye to the eggshell.* Vinegar is an acid, and eggshells are bound together by a basic molecule called calcium carbonate. The eggshells base molecules assure that neutral and basic solutions will not change the eggshell. However, vinegar will react with the calcium carbonate shell to dissolve it slightly, allowing the dye molecules to stick to the eggshell, giving you vibrantly colored eggs.* Without adding vinegar to your dye solution, you will likely get very faint coloring.

 Egg in vinegar. The bubbles on the shell are from gas released when the vinegar reacts with the calcium carbonate. Leave this overnight and the eggshell will dissolve!  Image by  Yat-Long Poon , from  Experimenting with Science , published by Wiley

Egg in vinegar. The bubbles on the shell are from gas released when the vinegar reacts with the calcium carbonate. Leave this overnight and the eggshell will dissolve! Image by Yat-Long Poon, from Experimenting with Science, published by Wiley

Have you ever tried changing the amount of vinegar added to your dye solution? Because acid is needed for the dye molecule to stick to the egg, you might predict that adding more vinegar to the solution will give you more colorful eggs. This may be true to an extent, but be careful! The acid reacts with calcium carbonate to produce carbon dioxide gas, which will float out of the solution, like carbonation in soda. This gas forming on the surface of the eggshell can leave behind streaks, causing a blotchy dye job. That is why there is an optimal amount of vinegar recommended for the dye solution. Too much vinegar or leaving the egg in the solution too long will eventually dissolve the eggshell. For a neat science experiment exploring this, click here ; you can also find this experiment in Dr. Olivia Mullins' book here!

Have you ever seen someone dye eggs with a silk tie? (If not, watch this clip from Martha Stewart!) The patterns on a silk tie can be transferred from the tie onto the egg by wrapping the egg in the tie and submerging it in water with vinegar. Eventually, some of the dye from the tie will be transferred to the eggshell. This is because silk ties are usually dyed using dyes that require an acid to bind – the same reason that dyeing eggs requires vinegar. By adding vinegar to the water, the tie’s dye molecules can be transferred over to the eggshell.

Now that you know the chemical principles behind this tradition in addition to some tips and tricks for optimal coloring, there is no reason for not making this Easter your most colorful yet.

*Going further: Egg dye molecules are typically sodium salts of a negatively charged molecule called a phenolic acid. In an acidic solution, it gains a H+, allowing it to interact with the surface of the eggshell. In particular, dye molecules interact with slightly negative parts of the eggshell, including the calcium carbonate and some parts of proteins.

Other fun egg experiments

Grow Egg Geodes
Suck an egg into a bottle
Make "Mood" Easter Eggs
Walk on Eggs
Make Water Marble Easter Eggs
 

References
·         “Silky Science: Tie-Dyeing Eggs.” Scientific American. 21 March 2013. https://www.scientificamerican.com/article/bring-science-home-silk-egg-dyeing/. 26 March 2017.
·         Stewart, Brian. “Egg Cetera #6: Hunting for the world’s oldest decorated eggs.” University of Cambridge. 10 April 2010. http://www.cam.ac.uk/research/news/egg-cetera-6-hunting-for-the-worlds-oldest-decorated-eggs . 26 March 2017.

 

Picture Credits:
Bunny and eggs: Superbass, CC BY-SA 4.0, via wikimedia commons
Basket of Bulgarian Orthodox Easter Eggs: lkonact via wikimedia commons
Egg in Vinegar: Yat-Long Poon, in Experimenting with Science, Wiley Publishing

 

The Genetics of the Luck o’ the Irish

by Ana Wang, Graduate Student at The Scripps Research Institute

With St. Patrick’s Day around the corner and a tumultuous start to 2017, most of us probably hope for a little of that fabled Luck o’ the Irish, and what’s more hopeful this time of year than finding a four-leaf clover? The myth of the four-leaf clover bringing good fortune has cultural origins that may be as simple as the fact that these clovers are rare, so finding one can make you feel special – or lucky. And they are pretty uncommon – on average, you’d have to search through 10,000 clovers to find one four-leaf clover! More rare still are clovers with five, six, seven, or more leaves – but they do exist. Currently, the world record is at 56 leaves on a clover found in Japan!

 Four-leaf clover

Four-leaf clover

Have you ever wondered why some clovers have four (or more) leaves? Or maybe you’ve wondered why more clovers don’t have four leaves. Well, look no further as we are going to delve into the science behind this lucky charm.

Whether or not a clover has the fortuitous fourth leaf – (or, more accurately leaflet) – is largely based on the code in the clover’s genetic material.  That being said, the exact cause of the fourth leaflet is hard to study and largely unknown, due to some quirks of the clover’s DNA. The common clover in North America is the white clover* which has four copies of each gene.** For reference, humans and most other organisms only have two copies of each gene. To add to the white clover’s genetic complexity, each chromosome (which contains the genes) in an individual clover often comes from a different species. You can imagine how hard it is to study lineage and inheritance with essentially four different parents!

 Five-leaf clover

Five-leaf clover

It is hypothesized that many genes, rather than a single gene, contribute to the determination of whether a clover is a trifoliate (three leaflets) or multifoliate (more than three leaflets). The Parrott Lab at the University of Georgia shed some light on this issue by studying three-leaf and four-or-more-leaf clovers in separate, but identical, surroundings. This set-up allowed the researchers to zero in on differences that stemmed from only genetics, as it kept the environmental influences of the two groups the same. Studying the DNA from the clovers showed that the multifoliate trait is recessive to the trifoliate trait. This means that even when a clover contains genes for both traits, it will have a trifoliate morphology. This is predominantly why the multifoliate variants are much more rare than the traditional three-leaf shamrock.

Genes are not the end of the four-leaf-clover story, however. The Parrott Lab also did some work on environmental influences. They ran their studies in both summer and winter and found more four-leaf clovers grew in the summertime, showing that genes AND the environment influence the number of leaves on a clover. Many suspect that chemicals and radiation may also increase the occurrence of four-or-more leaf clovers – but that has yet to be proven.

 Three-leaf shamrock   

Three-leaf shamrock

 

The four-leaf clover has become an international symbol of good luck. It is said that St. Patrick used the shamrock – the clover symbol of Ireland - to explain the Holy Trinity, with each leaflet representing one hypostasis . It is also said that the three leaflets represent hope, faith, and love. To many today, the fourth leaflet on a four-leaf-clover represents luck. To many in the Middle Ages, it was believed to bestow the carrier with the magical power to see fairies. To  plant biologists, though, it can represent the amazing complexity and infinite possibilities that lie within even a seemingly simple and common weed.

 

*The scientific name for the white clover is Trifolium repens, where trifolium refers to three leaves.

**Organisms with four copies of each gene are called allotetrapoloids.

 

References:
·         “Most Leaves on a clover.” Guinness World Records. Web. 15 March, 2017.
·         Tashiro, Rebecca M., et al. Leaf Trait Coloration in White Clover and Molecular Mapping of the Red Midrib and Leaflet Number Traits. Crop Science 50, 1260-1268 (2010).

 

Images:
Many clovers: By JPS68via Wikimedia Commons
Four-leaf clover: By Calignano via Wikimedia Commons                                            
Five-leaf clover: By 本人 - 本人, via Wikimedia Commons
Three-leaf Shamrock: via Wikimedia Commons