My Art Show

Last night I held my show for my "Beauty of Science" Collection.

It was a good Night. http://cutebot.tumblr.com/

Theory of Endosymbiosis

This Is The Paper I Wrote on Endosymbiosis for Dr. Hettes' Cellular Biology Class, This really isn't that good because i wrote it in 3 hours :(

The evolution of our ancestry has long been a contested subject amongst biologists. Surely, the most interesting of topics has been the discussion on the endosymbiotic theory of organelles; a process that has incorporated various ubiquitous cellular ‘machinery’ into the cells of eukaryotes to perform highly specified jobs within the cell. However many theories are thrown about, the question remains: How did we end up with these small factories in our cells? Organelles such as the mitochondria and the chloroplasts are much too complex to have originated from the cell itself, or rather, originate autogenously, and many pieces of information point to the fact that it is highly unlikely that these organelles came from the cell itself. So, if not originating from the eukaryotic cells, where did these organelles come from? How did they manage to become incorporated into the cells for presumably a billion or so plus years? Other contested endosymbionts such as Peroxisomes, flagella, or even microtubules are perhaps too simple to have been from extracellular sources. What is the evidence behind these endosymbiotic organelles? These questions and many of the proposed theories are some of the most intriguing topics of discussion related to endosymbiotic theory.

While Lynn Margulis only introduced the proposed theory of endosymbiosis formally in recent decades, the idea was around long before Margulis’ time. The idea of a symbiotic relationship between two cellular organisms was first proposed by Konstantin Merezhkovski in 1905. His work in studying lichens (a composite organism that is symbiotic in nature), as well as contemporary ideas on cyanobacteria, sparked the idea of chloroplasts as a symbiotic component of plants cells (Margulis, 1993) . A man named Ivan Wallin proposed a similar idea in 1920, relating the idea that because mitochondria divide in cells much in the way bacteria do, and most of mitochondrial behavior is much like that of bacteria, postulating that mitochondria must be symbiotic within the eukaryotic cell. Margulis drew heavily on their work when writing her many books on the nature of endosymbiosis, and is recognized as the main proprietor of Endosymbiotic theory. Her integration of cellular biology, biochemistry, knowledge of the young Earth, and the theories behind life’s complex evolution have coalesced into a formal and unified theory of Eukaryotic origins, and gives us an idea of our own unicellular origins.

The most accepted forms of endosymbionts include mitochondria, and chloroplasts, which in structure and function most represent their bacterial ancestors. Mitochondria are found in virtually every eukaryotic cell, providing energy via synthesis of ATP from aerobic respiration, and are especially concentrated where needs for ATP is greatest. This process is very similar to prokaryotic bacteria, which derive energy from their environment by a very similar process. Chloroplasts are the organelles responsible for converting sunlight into energy via photosynthesis but this occurs in only some organisms such as plants, algae and bacteria (although not in Archaea) . The fact that this process occurs in photosynthetic bacteria, gave rise to the notion that chloroplasts had an extracellular origin, as first postulated by Merezhkovski. The most difficult organelles to comprehend as being endosymbionts are the peroxisomes and undulipodium. It is thought that peroxisomes are endosymbiotic with the cells in eukaryotes and are found in nearly every eukaryotic cell. The fact that peroxisomes are not part of the endomembrane system and the presence of similar proteins in the organelles suggests an endosymbiotic nature of the peroxisome. However, this notion may be disputed as synthesis of the peroxisome from the endoplasmic reticulum has been demonstrated and peroxisomes may in fact be part of the endomembrane system. Also, it should be noted that the similarity of proteins in many different peroxisomes across species should come as no surprise, as they all share a similar function. Undulipodium are the most interesting of the proposed endosymbionts. They are proposed to be from a group of bacteria called spirochetes. The spirochetes are a type of bacteria that have a complex of many microtubules that form flagella. However, in my own personal opinion, the integration of a completely separate organism is a whole lot more complicated than the simple two- protein ATP-ase that makes up flagellum. Flagella are little more than a rotor protein and a stator protein within an ATP-ase, with an attached microtubule to the rotor protein to serves as the driving force of the cell through its matrix.

The main theory of endosymbiosis is that at one time, proto-eukaryotic cells acquired proto-bacteria within their cellular matrix, which tended to be beneficial for both the proto-eukaryote and the proto-bacterium, as the proto-eukaryote gained a cellular machine that provided a specific function to the overall function of the cell, such as photosynthesis, or motility; and the proto-bacteria gained a living environment, and provided protection. Although, there are different mechanisms that are thought to have incorporated these proto-bacteria in the proto-eukaryotes. Serial endosymbiotic theory proposed the idea that these endosymbionts have been incorporated into the host cell one at a time, integrating these cells, and eventually the cells began to independently divide and continue on within the cell. The cells are thought to have phagocitzed other living cells for nutrients and that unsuccessful digestion of these cells could have led to a symbiotic relationship between the two. However, I find that there are many flaws with this proposal, even though it is the most supported theory of endosybiosis’s mechanisms. The fact that a cell that requires energy by phagocytizing other bacteria and it not being able to digest said bacteria, is one that is in poor shape and within the context of an early earth, these cells would probably not survive long. Also, there are no bacteria that actively use phagocytosis for predation (Margulis, 1993), and therefore the likelihood of these cells predating on these proto-bacteria is highly unlikely. All of these things together seem very unlikely, especially within the context of the evolving progression of life. It could be highly feasible that a few singularities of these events happening, but the entire basis of multi-cellular life depending on these rare events is improbable.

Another theory of endosymbiosis includes the autogenous theory of endosymbiosis. This idea postulates that the proto-eukaryotic cell itself formed its own organelles by invaginations of the plasma membrane and assorted proteins and enzymes came to work in these organelles developing specific jobs. This theory was hypothesized by David T. Smith and Cavalier in 1987, which was quickly pushed aside by Margulis’ theory a few years later. This theory is also unlikely because there is empirical evidence that mitochondria and chloroplasts have their own separate DNA, which highly resembles DNA of bacteria.

Yet there is another theory, somewhat newer than the rest, which plays with the idea that perhaps ancient mitochondria and chloroplasts were not actively engulfed by the host cell, but instead were parasitic bacteria that preyed upon the host cells, and do to mutual benefit of this symbiosis, stuck together through the ages.

The radical state of the early Earth had much to do with the formation and shaping of life on our planet, and therefore the constant flux of materials on earth had a hand in directing the evolutionary history of life. Most important (to us, anyway) is the beginnings of multicellular life. David Smith once noted “Many symbiotes are found in nutrient poor conditions or in hosts which depend on a nutrient poor diet” (Smith, 1987), which is probably true in respect to the formation of multicellular life.

During Earth’s early years, the atmosphere was full of noxious gases that most (if not all) multicellular life could not thrive in. However many ancient bacteria were very adept at converting noxious gases such as Carbon dioxide into oxygen by way of photosynthesis, these bacteria, like Cyanobacteria, thrived and converted vast amounts of carbon dioxide into diatomic oxygen. After many, many years of this process, the levels of oxygen rose sharply and levels of carbon dioxide decreased. Oxygen is actually a very corrosive element and is toxic to many organisms, especially ancient bacteria. Toxic levels of oxygen increased, and a carbon dioxide food source dwindled. There was hypothesized to be a mass die-off of organisms due to the toxic oxygen levels, but there were oxygen-loving organisms known as proto-mitochondria that thrived and survived in this new environment. Perhaps proto-mitochondria, were aerobic bacteria which oxidized fermentation products completely into carbon dioxide and water. But how did these protomitochondria end up in the larger cells? These proto-mitochondria are hypothesized to be parasitic ( this idea is backed up with the fact that many of the related bacteria to proto-mitochondria are in fact parasitic beings) and took advantage of the other weakened cells on early Earth. Cyanobacteria, the precursors to chloroplasts may have taken advantage of the waste products of the mitochondria to produce energy completely for the cell. The succession of mitochondria to chloroplasts also explains the fact that most all eukaryotic cells have mitochondria, whereas only those in the Plantae and some Fungi have the ability to photosynthesize. If an entire species of proto-mitochondria were parasitic, this would also help explain the large occurrence of these organelles, rather than singularities.

Sources

Ahmadijan, V.; Paracer, S. (1986), Symbiosis: an Introduction to Biological Associations, University Press of New England

Gray, M.; Doolittle, W.F. (1982), Has the Endosymbiont Hypothesis Been Proven?, Dalhousie University, MICROBIOLOGICAL REVIEWS, Retrieved from:

http://mmbr.asm.org/cgi/reprint/46/1/1?view=long&pmid=6178009

On March 23, 2009

Lane, N. (2006), Power, Sex, Suicide: Mitochondria and the Meaning of Life, Oxford University Press.

Margulis, L. (1993), Symbiosis in Cell Evolution, W.H. Freemen Company Press

Oxford University (2008), Oxford Dictionary of Biology, Oxford University Press.

Smith, D.C., Douglas, A.E. (1987), The Biology of Symbiosis, Edward Arnold (Publishers) Ltd.

Thomas, L. (1974), The Lives Of a Cell, The Viking Press Inc.

Tzagoloff, A. (1982), Mitochondria, Plenum Press

My Moment of Science

Sounds like a Scrubs show title, but really yesterday I had one of the most meaningful scientific moment, where suddenly something made so much sense, and suddenly I knew that I was going to be in science for the rest of my life. This is a dynein protein complex, and it transports vessicles around the cell. And I saw the shape of this protein complex, was told how it works and started to cry, because it was just something that made so much sense and something that was so amazing in its function and complexity. I told a few people about this experience and was laughed at, which i expected, it was a rather nerdy thing to do. But even though I probably won't end up in something like cellular biology, i know that i'll stay in science, more specifically biology, because i know that there are more moments like this to come in my life, and this is the kind of life that i would love to have. I figure that this is kind of like my own personal religious experience, and now i want to be in endless pursuit of this wonderful, never ending field of Science.

Also, my schedule for next year

• Sensation and Perception (8:30- 9:20)
• Experimental Methods (9:30- 10:20)
• Child Development (10:30- 11:20)
• Developmental Biology (1:00- 1:50)
• Astronomy (9:30- 10:50)

-Genes Of Synesthesia-

This Isn't in lieu of a blog tomorrow, i'm just really excited about it, seeing as I'm a synesthesthete and an amateur scientist.

Seeing Sounds Or Hearing Colors: Scientists Narrow Search For Genes Associated With Synesthesia

ScienceDaily (Feb. 6, 2009) — A new study identifies specific chromosomal regions linked to auditory visual synaesthesia, a neurological condition characterized by seeing colors in response to sounds. The research, published online on February 5th in the American Journal of Human Genetics, makes major strides towards identifying the genes that underlie synaesthesia and may eventually lead to improved understanding of typical and atypical cognitive development.

In synaesthesia, which affects less than 1% of the population, stimulation of one sensory pathway results in experiences in another pathway (e.g. hearing sounds triggers colors) or in a different facet of the same pathway (e.g. reading black text trigger colors). "Synaesthesia is known to run in families but the genetics of synaesthesia are not well understood," says lead study author Dr. Julian E. Asher from the Department of Genomic Medicine at Imperial College London.

Dr. Asher designed a study to look for genes linked to auditory visual synaesthesia. The research, performed as part of Dr Asher's PhD in Prof. Anthony Monaco's laboratory at the Wellcome Trust Centre for Human Genetics at the University of Oxford in collaboration with Prof. Simon Baron-Cohen at the Department of Psychiatry at the University of Cambridge, involved a sophisticated genome-wide screen to search for susceptibility genes linked to auditory-visual synaesthesia.

The research team identified four candidate regions linked with susceptibility to synaesthesia but no support was found for an earlier theory of linkage to the X-chromosome. Although the resolution of the scan makes identifying candidate genes challenging, the researchers identified a number of interesting genes.

"The region on chromosome 2 with the strongest linkage is particularly interesting as it has been previously linked to autism," offers Dr. Asher. "Sensory and perceptual abnormalities are common in autism spectrum conditions and synaesthesia is sometimes reported as a symptom." Candidate genes associated with epilepsy, dyslexia, learning and memory are also located in the candidate regions.

The findings indicate that the genetic basis of auditory-visual synaesthesia is more complex than originally believed and may be due to a combination of multiple genes subject to multiple modes of inheritance. "This study comprises a significant step towards identifying the genetic substrates underlying synaesthesia, with important implications for our understanding of the role of genes in human cognition and perception," concludes Dr. Asher.

The researchers include Julian E. Asher, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK, University of Cambridge, Cambridge, UK; Janine A. Lamb, University of Manchester, Manchester, UK; Denise Brocklebank, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK; Jean-Baptiste Cazier, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK; Elena Maestrini, University of Bologna, Bologna, Italy; Laura Addis, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK; Mallika Sen, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK; Simon Baron-Cohen, University of Cambridge, Cambridge, UK, and Anthony P. Monaco, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.

Cell Press (2009, February 6). Seeing Sounds Or Hearing Colors: Scientists Narrow Search For Genes Associated With Synesthesia.ScienceDaily. Retrieved February 7, 2009, from http://www.sciencedaily.com/releases/2009/02/090205133728.htm

Spring (tentatively)

 Interim is pretty much officially over, but I won't have anything to write about until tomorrow at least, so keep your hats on folks (actually I really don't think anyone reads this blog, and that I pretty much do it for kicks and giggles). But, Medical Botany didn't turn out to be that bad, mostly just tons of studying, and memorizing a hundred or so plants for the exam. But at least now I know what plants to use to treat HIV if I get stuck in the woods, or which plant's resin to use to torture people á lá Bluebeard the Pirate.

Also during interim I got the privilege to sit in on Dr. Moss's "Crash Course" Immunology lecture which was rather interesting. Dr. Moss, in my book, is one of the best professors i've encountered at Wofford thus far (but I would have to contest that all the professors here are top notch!), and I feel that he is one of the most easy-going and interesting people here. But immunology was cool, and I can't wait to take it later on as a legitimate class.

Tomorrow spring classes will start and I can get beck to being uber productive and stressed out (yay!) and i'll probably get back into the actual science aspect of our school, instead of posting my old Genetics papers (sorry about doing that, it was lame, i know).

The Genetics Of Intelligence

The following is my Genetics paper from semester

The origin of human intelligence has been the subject of scientific inquiry for many, many years, and with the research behind this exciting field picking up speed, pin-pointing the basis of human intelligence is becoming clearer and closer than ever. In this search for what makes us intelligent, there have been many discoveries, many obstacles and much that we have learned about our intelligence; but we still have yet to come across a solid conclusion to finally close the book once and for all on the inheritance, the genetic properties and the inner workings of intelligence. As far as we know there is no single gene for intelligence, be it IQ, reasoning, verbal skills, or memory. Intelligence has been found to be both genetic and environmental, a selective force in our evolution, and still a highly contested and researched area in the field of genetics.

To say that genes and environmental factors operate separately is totally false when it comes to the workings of intelligence, especially that of human beings. Many genes influence our intelligence, but not in the way that we would like to imagine. Most of the genes related to intelligence are round-about and they are genes whose primary function has little to do with IQ, memory, or reasoning. One of these genes uncovered in the early 1990’s was IGF2R, an insulin-like growth factor that is active only in the brain and is passed down maternally. If there was a link to the gene and intelligence, it would seem to suggest that intelligence was inherited from the mother; but upon duplication of gene manipulation, the results were disappointing. Other genes have been identified, such as INTLQ1, INTLQ2, and INTLQ3, which yield more promise for the future of intelligence genes. INTLQ1 is a quantitative trait locus, which is a region on a chromosome which contains one or more genes that contribute to a certain quantitative trait, such as intelligence. These genes all contribute minutely to the trait, but they work together to specify the trait.[1] INTLQ1 is found on chromosome 4 and contributes to cognitive abilities such as vocabulary, memory, and a small part of reasoning.[2] This QTL has been the most conclusive of the three, and the main researchers of this QTL, Devlin et al, have concluded that there is a heritability correlation of 48% of genetic inheritance evident in a correlational study. [3] Although, this study is not purely genetic as it has to include pre-natal conditions of those individuals in the womb and the behaviors of the mothers while pregnant. The other QTLs associated with intelligence, INTLQ2 and INTLQ3, are very loosely defined at this point, and very minimal influence has been shown to affect verbal ability by these genes. In order to further prove the influence of genes, scientists on the sorely “nature” side of the debate started twin studies, taking sample IQ tests of identical twins, fraternal twins, siblings and others in order to compare the tests of those with identical genes, similar genes and non-related genes.

Comparative IQ tests

% correlation
The Same Person Tested Twice 87
Identical Twins Reared Together 86
Identical Twins Reared Apart 76
Fraternal Twins Reared Together 55
Biological Siblings 47
Parents and Children Living together 40
Parents and Children Living Apart 31
Adopted Children Living Together 0
Unrelated People Living Apart 0





This correlational study seems to suggest that the genes behind intelligence are one of the driving factor in human aptitude and because there is no correlation with adopted children living together, environment seems to play a negligible role, but really, the conclusion is that intelligence is 50% inherited. Over time, the percent of inherited intelligence actually rises. As an individual grows up, they shed their influences and begin to express their own innate intelligence; a person’s genes drives then to pick their own environment based on their innate aptitudes.[4]

Genes can also indirectly influence intelligence and how we learn. Certain genes which encode proteins that can help brain function and neural pathways will also affect intelligence and aptitude. Research indicates high intelligence related to how efficient the neural pathway is; genes that strengthen this pathway could contribute greatly to intelligence[5]. Genetic contributions to structure also can affect the way in which the brain works. Genes that strengthen mylinated sheaths could let the person who has them be able to transduce a message faster than others, recalling information faster and learning quicker. Genes that enhance cortical regions and make the regions larger in these individuals, could be able to be more adept at spatial reasoning than others, or have improved logical, mathematic or verbal skills because of increased brain volume. Also, a gene found to control the utilization of fatty acids called FADS2, can increase the IQ of children who are breast-fed as infants by an average of seven points[6]. This interaction between genes and environment confirms that intelligence is a multifactorial trait, and intelligence is not necessarily influenced directly by a single gene. Genes for other traits can also affect intelligence, such as diseases like PKU and Down’s syndrome can greatly impact the development of intelligence, either by metabolic consequences or chromosomal abnormality. Genes do not have to be connected to learning or aptitude in any way to be able to affect intelligence.

Intelligence can also be a product of evolutionary pressure, as seen in some groups of people throughout time. Ashkenazi Jews are a prime example of selective evolutionary pressure in intelligence. There has been major evidence to support the idea that Jews descended from the Ashkenazi line have a higher average IQ than other groups of people throughout the world.[7] The idea behind this theory is that because of strict religious law dictating marriage of other Ashkenazi Jews, the variation in the population goes down, restricting the different alleles available. Also, discrimination towards these people throughout history may have favored higher intelligence individuals, where only the cleverest of individuals survived. Historically, these people have also been assigned to mentally rigorous jobs such as banker and accountants and to do well in these jobs would have meant a higher life standard, which would be evolutionarily advantageous. But the Ashkenazim aren’t the only people in which intelligence is a selecting factor; in fact, all humans to a degree are affected by the selective pressures of evolution. Individuals tend to choose partners in marriage who are in the same intelligence range[8], which acts as an assortative mating mechanism. This kind of mating can reduce variation within a species and develop trends towards certain phenotypes, possibly creating ‘cognitive castes’[9]. In our culture, the phenotype is an increase in IQ over successive generations.

Much of the excitement generated by genetic intelligence studies hasn’t all been positive. Some research in this field is highly prone to incorrect interpretation and subject to racism. One of the most controversial books on this topic was The Bell Curve, which caused much uproar by reasoning that the over representation of minorities in the lower ranges of IQ scores meant that they were of an inferior stock of intelligence. Many adversaries of this view pointedly note that the language of the test is not usually the first language of the test-takers, therefore, the test-takers usually score lower than they would have. These debaters also point out that because of racial inequality, these people usually live in lower socioeconomic classes and are not afforded the same privileges as others and therefore do not have as many chances to express their intelligence.

The research of human intelligence will progress onward for years to come. as genetics continues to grow and develop, so will our understanding of our own aptitude; understanding of particular genes and the interactions of genes with their environments. And while much controversy will still surround the “nature/nurture” debate, the appearance of false positives reported, and the tracking of evolutionary changes will continue in this field, eventually we will uncover the secrets of the mechanics of human aptitude and intelligence.

[1] Oxford Dictionary of Biology, Oxford Press, Cambridge 6th edition, 2008
[2] OMIM 603783; Devlin et al.
[3] Devlin, B.; Fienberg, Steven; Resnick, Daniel; Roeder, Kathryn; Intelligence, Genes and Success; 1997 ( Copernicus Publishing, NYC) pgs.56-57

[4] Ridley, Matt. Genome; HarperCollins Press, NYC (1999) pg. 85

[5] University of California - Irvine. "Brain Network Related To Intelligence Identified." ScienceDaily 19 September 2007. 31 October 2008 .
[6] Duke University. "Breastfeeding Boosts IQ in Infants With 'Helpful' Genetic Variant." ScienceDaily 6 November 2007. 31 October 2008
[7] Haslinger, Kiryn.," A Jewish gene for intelligence?" Scientific American September 2005


[8] Vernon, Philip E., Intelligence: Heredity and Environment; 1979 (W.H. Freeman and Company, San Francisco) pg. 184
[9] Devlin et al. Pg 59

Interim- Medical Botany

So Interim is now officially underway, and I am drowning in a sea of plants and medical folklore. It’s interesting enough and I'm glad that I picked a relatively hard class for an interim project. Although it’s a ton of work for a month long class (two textbooks, lengthy presentations and field trips, complete with tests and exams), I'm starting to feel envious of those who picked interim projects like Knitting, Chess, and How to Watch A Movie. But I guess I’ll be more enriched by the end of the month than some of my peers (maybe not The War and Peace kids though; we’re equals in our pain).
Dr. Rayner is pretty interesting, albeit a bit scatterbrained and pretty strange (but most intelligent people are). And after you get used to random bird calls during class and his five minute long tangents, it’s pretty fun. Class started Monday, where we learned about leaf arrangement and composition. And now when I look at plants, even the silly Lil’ Green Patch plants on Facebook, I’ll identify their leaf patterns (yup, that’s definitely pinnately compounded leaf composition on that little critter there…). Wednesday, we heard a guest lecture on the glory of the old south’s cotton plantations (provided he did speak out against the evils of slavery, which didn’t sound convincing as his family had been in the south since before time). Furthermore, his lecture on cotton was alright, but the following lecture on rice put everyone to sleep, or at least sent them to a land of day dreaming.
We’re learning about local plant life, such as Indigo, Cotton, and Rice; along with Cherokee herbal remedies, and that’s all well and dandy (and it’s fun to watch people shove plants in to their mouths). But where I start to question the class is when I don’t see evidence for these claims. Is there scientific basis in these remedies? What is the validity of the claims of these plants? I guess maybe I imagined this class differently, and I'm taking as a true science class instead of a Historical science which I think it really is. The textbook is more true to what I think is the real meaning of the class, and I'm learning a lot about nature that I find really interesting.
As I'm writing this now, I'm sitting in the Biology hallway outside of the class room, waiting for class, and I'm sitting next to someone who I’ve met many times before, and has been to my dorm room many times because of my roommate. Yet when I try to strike up a conversation about his weekend, he grunts and resumes napping in the hall. At this, I realize that Dr. Rayner adds an invaluable part to the class: Humor. The best thing I’ve seen him do lately is an impersonation of a giraffe eating (one of the top ten funniest things I’ve seen in my life so far). The class starts at 9 o’clock each morning, which during interim is the crack of dawn, I believe. But the class is basically lifeless; we sit staring at each other not really saying much. The only real banter that goes on is between me and one of my friends who happens to sit across from me. Within the next three hours of my life, Medical Botany will include Dr. Rayner trying to get everyone out of their shells, Dr. Rayner trying to get the class to participate ( it always ends up that I'm the one talking, which I hate), and probably a lecture about whatever we’re talking about (today its tobacco and the history there of).
Whatever the outcome of the class (good, bad or ugly) I'm trying to make the most out of it and learn as much as I can, and just hope that I don’t die of being over worked.