Repeated stress exposure results in a survival-reproduction trade off in Drosophila Melanogaster.

Repeated stress exposure results in a survival–reproduction trade-off in Drosophila melanogaster | Proceedings of the Royal Society of London B: Biological Sciences Researchers took 35 isogenic female lines from London, Ontario, Canada where the multiple cold cycles occur. They grew flies up from these different lines and sorted them via CO2 anesthetics, with 15 Virgin females per vial and 30 virgin males per vial. Both male and female vials were stored at 22 degrees Celsius. Females, after waiting 3 days to eliminate possibility of CO2 effects the flies, the flies where placed into one of four groups in order to control for varying conditions. One group contained flies only exposed to 22 degrees C. One was exposed to -.5 degrees C for 10 hrs. Another was a multiple cold exposure, where flies were either exposed to 2, 3, 4, or 5 two hour periods of -.5 degrees C, with 22 hrs in between exposure times and ending at 7 days old to account for age influences. The last group was a single ...

January 23, 2017 Zhan, Y. P.. Liu, L.. Zhu, Y.. Taotie neurons regulate appetite in Drosophila. Nature 7, Article number: 13633(2016). Doi: 10.1038/ncomms13633

New findings regarding the neurological regulation of feeding rate suggest interesting factors behind fruit fly nutrition and obesity. After a screening of GAL4 lines in adult Drosophila brains, one line (Taotie-GAL4) was identified to have an impact on food intake. Further study showed that activation of Taotie neurons increased food intake over five-fold when compared to control flies. However, when starved for over 60 hours, Taotie activated flies showed no difference in food intake compared to equally starved non-activated flies. This suggests that activation of the Taotie neuron is involved in hunger response normally. Activation of the Taotie neuron in flies that were sufficiently nourished resulted in fly obesity. Interestingly, inactivation of activated neurons effectively reversed the obese trend, as deactivated flies not only returned to normal feeding habits, but effectively controlled their food intake until normalcy was established. 

Role of the metF and metJ genes on the vitamin B12 regulation of methionine gene expression: Involvement of N5-methyltetrahydrofolic acid

This article examines the process of metE repression in E coli strains. MetE is repressed with the assistance of many other molecules within the methionine pathways, it has also previously been known to be repressed by presence methionine in the growth medium. Studies also have shown that when E coli strains are grown in the presence of B12 vitamin, metE is significantly repressed. The exact pathway of repression of metE through vitamin B12 has not been concluded. This study aimed to determine the role of metF in B12 repression, and MetJ in the repression of metF and metE through B12.  

Genome and metagenome analyses reveal adaptive evolution of the host and interaction with the gut microbiota in the goose

This research team wanted to investigate the genetic basis of the unique digestive characteristics of geese and swan geese compared to other poultry. Of particular interest were the geese’s abilities relative to liver fat deposition and fiber digestion. The goose genome contains many rapidly changing digestive function genes, genes that are not found in cousin species. The researchers believed that gut microbiota cause, at least partially, the goose’s unique digestive abilities. Metagenome analysis helped the team establish and understand the influence of microbiota in geese.

The Esg Gene is Involved in Nicotine Sensitivity in Drosophila melanogaster

PLOS ONE: The Esg Gene Is Involved in Nicotine Sensitivity in Drosophila melanogaster In this article authors attempted to identify genes that are involved in nicotine sensitivity. They tested white1118 (w1118) flies against different mutants by exposing each group of flies to nicotine that was dissolved in water and then aerosolized. The parameter focused on was Half Recovery Time (HRT). HRT is the time it takes for half of a group of flies to recover from volatilized nicotine. For w1118 flies the standard amount of nicotine given based on the HRT was 32 ng of nicotine over 30 minutes. The mutant lines L4 and L70 had a significantly different response to nicotine exposure. Both showed an increase in hypersensitivity. L4 is an escargot (esg) loss-of-function gene, where L70 seems to down regulate esg genes. To test that L4 actually creates a loss of function is esg genes, researchers mutated other known esg regulating genes and exposed them to the same nicotine tests with their ...

Using Drosophila to discover mechanisms underlying type 2 diabetes

Pathways involving glucose in Drosophila Melanogaster are similar to mammalian pathways. These similarities make fruit flies a simple and easy model for study. This research shows how fruit flies are an effective model to study the functional genes that are involved in type two diabetes, which is characterized by an insulin deficiency. The pathways in mammals and drosophila have definite differences, but the particular similarities cited by these researchers provided enough evidence to perform a GWAS study. GWAS identified orthologous genes that will help to provide a springboard for looking at genetic risk factors that will hopefully contribute to Diabetes treatment options in the future. It was interesting to read an article that included GWAS. The definition was very helpful in clarifying how we have used it in our lab. This article defined GWA in a helpful way, "that examines the association between large numbers of genetic variants [e.g. single-nucleotide polymorphisms (SNPs)] ...

Porcine Zygote Injection with Cas9/sgRNA Results in DMD-Modified Pig with Muscle Dystrophy.

One of the major obstacles in Duchenne's muscular dystrophy (DMD) research is the ability to efficiently create model organisms for study. Because of the physiological effects and of DMD, traditional breeding of pigs is extremely difficult. Using the CRISPR/Cas9 genome-editing technology, researchers in this study created a pig model for human DMD by injecting a zygote with the Cas9 mRNA and short guide RNA. They had excellent success, resulting in few to no off-site mutations. Unfortunately, the study was only performed with two test subjects, which failed in the second. However, the target sites were correctly cleaved in most tissues of the successful subject. This new discovery will hopefully lead to more effective creation of DMD study models.

Human oral microbiome and prospective risk for pancreatic cancer: a population-based nested case-control study

The micro biome of the human mouth may play a role in causing pancreatic cancer. 361 individuals with adenocarcinoma of the pancreas and 371 control individuals gave mouth wash samples. The results provided a positive correlation between the carriage of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and risk for pancreatic cancer. Phylum Fusobacteria and its genus Leptotrichia were associated with decreased pancreatic cancer risk. Chatson's lab is so cutting edge! There are so many studies showing correlations between the microbiome and almost every disease. Very few studies have been published looking into the genetics of the relationship.

Lactobacillus plantarum favors the early emergence of fit and fertile adult Drosophila upon chronic undernutrition

The focus of the paper that I decided to review this week discusses the importance of Lactobacillus plantarum WJL in the Drosophila lifespan. In order to spoil the surprise of the paper, I'll reveal their final verdict now. Essentially, they found that L. plantarum WJL has a beneficial effect on Drosophila. Their data shows that this variety of plantarum specifically has an effect on early pupariation and early adult emergence, and that when compared to their axenic counterparts, the acceleration of growth experienced by mono-associated flies is not deleterious. Additionally, they show that this bacteria can increase the lifespan of male flies that are in a low nutrition environment.  I find it curious that this specific bacteria can accelerate larval development and extend lifespan, without affecting the the reproductive capacities of the flies, or as figure 3 suggests, not deleteriously affecting adult fitness. Under the idea of living ...