Writing in Biology

I am contacting you to express my strong interest in joining your laboratory as a graduate student in the Neuroscience and Behavior masters program.Your work with zebra fish and optogenetics is extremely fascinating and cutting edge. Understanding locomotion at the molecular level is something that has massive implications in the clinical world, and I would love to be a part of the team that elucidates it. Your recent work detailing the eight present GABA receptors in the developing central nervous system of zebrafish was a captivating read and the implications of your findings could result in large strides in the field of neuroscience. Of all of the other research opportunities on campus, yours stuck out to me because it’s focus is closely aligned with my own interests. I’ve been a student at this university for three years now, and have always desired to contribute towards some of the fantastic research conducted here, to which I believe yours is at the forefront.     

In this lab, benzoin was reduced by the addition of sodium borohydride. The product was identified as 1,2-diphenylethane-1,2-diol based on analysis of the reaction mechanism and comparative melting points taken from the literature. Sodium borohydride is a metal hydride that is capable of serving as a reducing agent. The reducing agent contains a metal hydrogen bond that is the source of a hydride ion. Sodium borohydride is a more selective reducing agent because of the polarity between the boron and hydrogen bond and as a result will only reduce aldehydes and ketones. The addition of sodium borohydride along with hydrochloric acid to the benzoin in ethanol provided the necessary components of the reaction to occur. The double bond to the oxygen in the benzoin was attacked by the sodium borohydride so that it became a single bonded negative oxygen which was then capable of reacting with the hydrogen provided by the addition of hydrochloric acid and water. The quenching allowed the negative oxygen to bond with hydrogen and become a hydroxyl group. The reduction reaction causes oxygen to lose bonds and, in this case, the double bond to oxygen in benzoin became a single bond to a hydroxyl group in hydrobenzoin. A crude product was generated as a first step and then recrystallized to purify the product. The purified product, along with the starting material and crude product were then analyzed with thin layer chromatography and melting points.

Our experiment studies cellar spider web weight and production in relation to the temperature of their surrounding environment.  This experiment can be used as a microcosm for Earth and may show the effects that climate change will have on cellar spiders. Globally, species are expected to shift locations in response to climate change.  When the area the organisms are in becomes too hot or cold, they move towards the poles or equator accordingly to adjust for the change in temperature. If the area becomes too hot, they will generally move towards the poles in order to stay in an environment that suits their temperature needs.  If the area becomes too cold, they will move to a warmer area, which is generally towards the equator. Most of the Earth is expected to warm over the next several decades, but there are some areas that are expected to get colder.

    Spider webs are extremely thin, the largest silk fibers being only 5-10 μm. Some can be as thin as only 50 nm, making spider webs very difficult to measure. We found a publication that explains the use of light microscopy to accurately and precisely measure the width of spider webs. Webs are extremely strong, comparable to steel and also super flexible. However, because of the microscopic size, the different principles of silk have not been greatly investigated. In this review they used a polarized light microscope to illuminate the spider webs and images were taken that were then used for comparisons and measurements.

Georges bank is a region of ocean just south of the Gulf of Maine and East of cape cod Massachusetts. This region is only 45 meters deep, allowing sunlight to reach the bottom making it very nutrient reach. Furthermore, the gulf stream and Labrador current intersect here, bringing their own nutrients and “mixing it up.” The cold water makes it perfect for the Atlantic cod and a variety of other fish species. Due to this large productivity, Georges Banks has been an important economic fishing zone. Unfortunately overfishing over the last hundreds of years has decreased the biomass of this area by nearly 90%. 66% of this decline has occurred in the last 50 years alone. Unfortunately this does not seem to be changing, despite attempts of (admittedly insufficient) regulation. Recent fears of global warming seem to be effecting the gulf of Maine significantly. Unfortunately the fish here are adjusted to live in the cold waters, and as water temperature rises it will only get harder for them to survive here. Not only is the loss of fish species tragic on its own, but we as humans rely on this area for food and money.

The family Gadidae contains fish such as the cod and haddock. There are 24 species of fish in this family. All of the Gadidae are marine dwelling fishes, with the exception of the Lota lota which lives in freshwater. This family is united by several characteristics. These fish have a single chin barble, three dorsal fins, two anal fins, and a diphycercal tail. Their pelvic fin is anterior to their pectoral fin, located along the same axis and close to their rostral end.

The Atlantic cod is a very notable species of Gadidae. These are a very R-Selected fish and females of about 5kg will lay 9 million eggs, though the amount will vary depending on the size of the fish. Cod are relatively long lived and live to be about 25 years of age. They are predators and will eat both other fish and invertebrates. Due to their low red muscle and high white muscle content, Cod are the perfect food fish. Their high presence in the north eastern united states have made them an economic staple. Unfortunately commercial fishing has diminished their populations drastically. Unfortunately global warming is making it more difficult for Cod to reproduce and further diminishing populations. Generally  Atlantic Cod only like to reproduce in waters colder than 12C, so even a tiny shift in temperature can have a drastic impact on their survival.

To determine the relationship between spider weight and spider web thickness, 3 different species of spiders of different sizes will be collected from various sites around campus. We will collect 2 spiders in each species. The spiders will be weighed on analytical scales and will be sorted based on weight. They will then be placed in separate containers  and will be allowed to spin out spider silk.The spiders will be left in their containers to make a web for 5 days. We will feed them 1 fruit fly each day. We will remove the web with tweezers and place onto a microscope slide. The silk will be fixed onto microscope slides using distilled water as a buffer. The silk will be observed under a microscope at 40x magnification and be characterized based on size, using a stage micrometer, and web type. The webs will be sorted based on type, and then subgroups will be made based on size. The data will be analyzed based on the spider species and then the web size will be compared to spider weight to determine if any correlation exists.

We want to contrast two different periods of starvation (3-days vs. 7-days) and see the impact on spiders’ eating habits (feeding rate, feeding interval) and movement. We also want to observe the combined impact of various environmental stressors and starvation (heat and cold) on spiders’ morphology and behavior. Since a study on long-term starvation revealed that there was difference in the behavior of wolf male and wolf female spiders after food deprivation ( ), we want to observe any difference in behavior due to short-term food deprivation. We also want to observe the impact of competition on predatory behavior after food-deprivation.

    We hypothesize that there would be no difference in morphology after a short starvation period, since metabolism is adjusted and resources are reallocated over a long time (Wilson, 2014). However, we expect there to be significant behavioral change between the not-starved spider and the 7-day-starved spider in terms of feeding speed and feeding amount. We expect the environmental stressors to negatively impact web-building abilities and feeding for all groups of spiders. And, we expect female wolf spiders to feed in a more uniform pattern compared to their male counterparts (reference ). We also expect there to be more aggression present (in the competitive group) between the 7-day starved spiders compared to both the 3-day starved spiders and not-starved spiders.

These studies of long-term starvation also reveal two fundamental facts about spider metabolism. During starvation period, resources will be reallocated from reproductive potential and growth to maintenance and survival to ensure that reproduction can take place when conditions improve (Wilson, 2014; ). Spiders do not adjust metabolism to maintain a constant body weight, rather their lipid is stored efficiently and prepare them for long periods of food deprivation (Jensen et al., 2010).

    Although the effect of long-term starvation has been widely studied on spider morphology, behavior and movement, research is scarce about the impact of short-term food deprivation. This scenario is a much more likely one in the real world, especially for house spiders whose insect supply is limited. Due to our regular interaction with these kinds of spider much of our surrounding environment is shaped by their predatory behaviors. In this proposal, we aim to look into the impacts of short-term starvation on the morphology, behavior and movement of common spiders in Amherst: wolf spiders and cellar spiders.

The feeding behavior of any species can tell us a lot about its metabolism, movement patterns, predatory instincts, and overall ecological impact on its surrounding biomass. Most species of spiders (order: Araneae) are predators, who feed on insects and small invertebrates through the synthesis of sticky webs. Their feeding pattern is mainly influenced by the size and shape of the prey and whether the spider has enough strength to overpower it: preys are supposed to be smaller than the spider’s body but larger than its head. Web-weaver spiders can also survive a long time without food due to spending minimal energy (reference.)

    Due to their unique metabolism and ability to survive without food for extended periods of time, the effect of long-term starvation has been widely studied in spiders. And, the results indicate that starvation still affects various spiders’ morphology, feeding behavior and movement patterns without causing prompt death. Southwestern longlegs spider, Physocyclus mexicanus, exhibit smaller body size, reduced weight, and smaller testis size under severe dietary restrictions (Wilson, 2014). Running crab spider, Philodromus rufus, feed at a higher rate after being starved (Haines and Sisojevic , 2012). The wolf spider, Pardosa agrestis, is more susceptible to cannibalistic tendencies when hungry (Samu et al., 1999). Food-limited wolf spider, Tigrosa helluo, show more locomotive activity than their satiated counterparts (Walker et al., 1999). And, spiders of various species show distinct aeronautic dispersal and ballooning movements after starvation (Mestre and Bonte, 2012; Weyman and Sunderland, 1994).