Writing in Biology

”It looked like a cat crossed with an otter crossed with a mongoose,” she says. “It used its long claws to tear into the snake and the mud around it, and later I observed it digging into the mud for snakes that were hiding.” McKenzie describes the Snanker as having short rounded ears that become flat to the head when the animal swims, a long muzzle with razor sharp teeth and large canines for puncturing its prey, long muscular legs, and webbed paws useful for swimming and walking in the mud. “They are mainly active during the day, and because of this their eyes are not as large as, say, the ocelot’s,” McKenzie says. After more observation, McKenzie was able to discover more about the seasonal changes and the mating process characteristic of the species. “As the dry season continued on, the green color on their pelts became less and less and faded into brown. I suspect that during the wet season, when they are mostly covered by vegetation, this makes them camouflage more easily into their surroundings.

Vitamin B6 (pyridozine) naturally occurs in many foods such as poultry, meats, fish, starchy vegetables, and non-citrus fruits.  People also may choose to take a dietary supplement containing the B6 vitamin in order to satisfy their daily needs.  Vitamin B6 is incredibly important for more than 100 enzyme reactions involved in metabolism.  Healthy levels of vitamin B6 contributes  largely to the production of hormones such as serotonin and norepinephrine, which influence mood.  Vitamin B6 also assists with the conversion of carbohydrates in food into glucose for storage and ATP.  Most importantly, however, this key vitamin helps control levels of the amino acid homocysteine in the blood.  This amino acid is largely associated with heart disease, although more reasearch is needed to determine exactly the two are interrelated. 

Sjogren's syndrome, also known as Sicca's syndrome, is an autoimmune disease that affects various organs (pancreas and the liver) and causes severe dryness in the mouth and eyes. There are various studies on this disease but scientists are still trying to figure out the genetic and/or environmental causes. A study done in 2013 by Christopher J. Lessard looks at "variants at multiple loci implicated in both innate and adaptive immune responses are associated with Sjögren’s syndrome." The contributors to this study formed a database to contain all the information about the disease in one place along with the various case studies, in order to bring awareness to Sjogren's syndrome. Something interesting about treatment of this disease, is the invention of artificial tears to combat the extreme dryness of the eyes. Because of the long list of symptoms, it has become difficult to identify a single cause as well as a well-rounded treatment plan.

It was in early June that it happened. McKenzie was sitting in vegetation by the shore of the water, observing the giant water lilies, when she realized that an anaconda was becoming dangerously close. “I panicked,” McKenzie recalls. “I had no idea what to do. I was frozen. But then, all of a sudden, a brownish-green blur flashed before my eyes. It didn’t even care that I was there,” she exclaimed. “The Snanker just jumped right in front of me and killed the anaconda immediately, swiftly dodging its head and biting it in the throat." But this creature was unlike anything she had ever seen before. As the animal devoured the giant snake, McKenzie was finally able to take in the details. It was huge, about seven feet long from nose to the tip of its tail, which was thick and muscular.

machinery produces gametes = testes
testis histoligcal picture, seminiferous tubules, each lobule has a single one of these, connected at the end, single piece
spermatogenic wave seen at different cross-sections of these STs
picture (label testis)
immature gametes but those at the bottom are sertoli cells
req’d for sperm maturation/production
dev of speratocytes into spermatids (mature towards the middle but not functional yet)
cells in the ISF
Leydig cells, have LH-receptors to make testosterones aka leydig make test in response to LH
sertoli cell has FSH-receptors, makes inhibin then NF effect that feeds on pituitary and hypo
blood testis barrier, how do the premordial germ cells get thru it
fluid in ST is different from serum (that’s how we know it is a barrier, active transport)
primary germ cells become spermatoccytes then ...

test can be converted to 2 horomes 5 alpha DHT and
reductase does this, when it is converted into this, ir can’t be reconverted, it becomes an androgen
araamotase converts testosterone to estragen
is testosterone acting via androgen that hits the androgen receptor or estrogen that hits and estrogen receptor?
androgen receptor that mediates effects of DHT
DHT is responsible for some thing in the male
test and DHT and how the receptor works
can be converted to DHT depending on the cell
test receptor is not bound to DNA, test binds to it, dissociation of HS protein and translocated to bind to DNA and regulate transcription of genes
that is why DHT and test can produce different effects, different chromatin sites = different genes and that is how they are different and are able to tell the difference

Through complementation analysis, unknown mutations within the yeast (Saccharomyces cerevisiae) adenine biosynthesis pathway were identified. Studying the ability of unknown mutant colonies to produce successful colonies with known mutants revealed the identity of the unknown mutation as either a mutation in Ade1 or Ade2. Four mutant strains were examined, two strains of the A mating type and two strains of the alpha mating type. The A type yeast produced living colonies when crossed with a known Ade2 mutant as well as the unknown alpha type mutants. The alpha mutants produced living colonies when crossed with a known Ade1 mutant as well as the unknown A type. Using complementation analysis it was determined that both unknown A mutations were in the Ade1 gene and both unknown alpha mutations were in the Ade2 gene.

3 hypothesis on why when surround-illuminated you are releasing less Glu and you are hyperpolarizing these cells that some how leads to depolarization of cone center presynaptic terminal membrane
1.) GABA hypothesis:
center + surround = less GABA released = less inhibition becomes horizontal cells become more hyperpolarized by surround cells
so if you give exogenous GABA, it blocks depolarization, abolishes the response
not just local when you do this so it can be changing input resistance of the whole membrane (explains suppression of HC feedback sys)
2.) EPHATIC HYPOTHESIS
adding charged cations is equivalent to depolarizing charge on the inside and might inibit cahnnel opening and reducing NT release
if this is correct you would expect finding a lot of open hemi-channels (1/2 gap junctions), not found in mammals
if you block these channels, you can suppress horizontal feedback (but you don’t know if it’s affecting just local synaptic region, could effect other VG-channels)
use blocker and you don’t see block of these gap junctions
if you get rid of these channels (lacks connexin), you can reduce but not eliminate CS LH
if you knock it they can go to a different compensatory change
can contribute but not the only mechanism
3.) pH hypothesis
release protons, artifically acidify/alkanize cleft you can account for horizontal feedback, has an effect
block-it clamps pH, changes in proton release can’t change pH and block feedback
show-it, have fish express reporter of pH (GFP) you get changes in pH in predicted region
timing of pH and magnitude changes at the right time, CS illumination and place

- the LCR was first identified and characterized in Globin genes
- in the human visual system, an LCR has an important role in choosing either red or green opsin in a mutually exclusive manner
- each cone expresses only one pigment
- an LCR stochastically chooses one of the 2 promoter sites of the red-green pigment locus
- the physical interaction b/c the promoter and LCR activates the transcription
- b/c the red and green pigment genes are located on the X chromosome next to each other, this mutually exclusive acivation alone ensures monoallelic expression, you get equal # of red and green cones b/c its random, randomly interact w/ the 2 promoters
- monoallelic because it is on the X chromosome (cells randomly inactivate X), this is why males are more likely to be colorblind
- sequence comparison of the mouse and human genomes revealed a 2-kb homology (H) region far upstream of the MOR28 cluster
- negative feedback regulation ensures that one receptor-one olfactory neuron rule in mouse
- attachment of the H region to the truncated YAC constructs restored the expression of all the transgenes in the cluster
- crossed it with the transgenic that they made and found that they don’t express the same cell = its monoallelic, the LCR is intact

The average rainfall in the whole of the Amazon River Basin is about 2300 mm per year, and there are two seasons: wet season and dry season, though it is always hot and humid (Project Amazonas). The Amazon River Basin is a mixture of fresh water and salt water called brackish water and in the wet season the water levels rise drastically (The Amazon River). McKenzie was there during the months of May, June, and July, and so experienced the end of the wet season, which normally lasts from January to May, and the beginning of the dry season, which continues on until December (Wet and Dry Season). “I saw parts of the jungle floor that were once covered in water dry up and become accessible to me and many of the jungle’s species,” McKenzie explains. She states that finding fish to eat was much easier in the latter two months, and snakes and other reptiles such as the Caiman became abundant.