Bacteria that kills off only male fruit flies

Scientist have been seeing a strange phenomenon that causes male fruit flies (Drosophila) to die. This was noticed during the 50's when they crossed two strains of the same fruit fly together only producing females. The geneticists believed it must have been from a mutation, however from further analysis it is seen now to be the cause of the endo-symbiotic bacteria Spiroplasma Poulsonii that stays inside the blood stream and later passes it onto the offspring from the oocytes. S.poulsonii is very specific in only ending of male embryos. There was no molecular mechanism that causes this yet, it was previously believed that they produce a kind of toxin (androcidin). Then Professor Bruno Lemaitre and Dr Toshiyuki Harumoto from EPFL found the gene named Spaid to encode protein that causes certain structures that localize on the X chromosome of male embryos then increasing the transcription of gene onto it. (1 &2)
Having that females have two XX chromosomes it is now understand why the males do not survive but the females are still able to. (1)
""To our knowledge, Spaid is the first bacterial effector protein identified to date that affects host cellular machinery in a sex-specific manner," says Harumoto. "And it is also, to our knowledge again, the first paper to identify an insect endosymbiont factor causing male killing. As such, we expect that it will have a big impact on the fields of symbiosis, sex determination and evolution."" (1)

references:
(1) Male Drosophila die due to bacteria
(2) paper of male killing toxin in a bacterial symbiont of drosophila

Low protein diet in early life increases lifespan in fruit flies

Researchers at the Francis Crick Institute have discovered that some fruit flies can live over twice as long as other Drosophila melanogaster. The flies that are fed a low protein diet early in life, and are switched onto a standard diet as adults, live longer. The researchers found that adult fruit flies release toxic lipids from their skin that shorten their lifespan. However, the lipids were found to be less toxic if the fly ate a low protein diet early in life, before it became an adult. The lipids function to prevent dehydration and stimulate mating behaviors.

The scientists also found that the lipids produced by the flies affect the other flies that are near them. So, if a fly is producing a more toxic lipid, they will have a shorter lifespan, and so will the flies around them.  Since flies affect their neighbors, it causes fruit flies to have a shorter lifespan when they are densely populated. However, when the flies were densely populated, but were genetically modified to produce less toxic lipids, the flies lived longer. Therefore, the scientists concluded that skin toxins cause the fruit flies to have a shorter lifespan, individually and in large groups.

I thought that this article was very interesting because it’s kind of counterintuitive. I would never have thought that something that flies need would be causing them to have shorter lifespans. The article states that humans also produce skin lipids to moisturize and protect our skin. It makes me wonder if the lipids produced by humans are toxic to us, and if there is a way to make them less toxic.  If less toxic lipids cause fruit flies to have longer lifespans, it could also have positive effects on humans.

Low protein diet in early life increases lifespan in fruit flies article

More information about fruit flies

Low protein diet in early life increases lifespan in fruit flies

Low protein diet in early life increases lifespan in fruit flies

                Scientists have recently used fruit flies to study how their lifespan is affected due to a low protein vs high protein diet in early life.  It was found that the flies that were raised with low protein were found to live longer than those raised on high protein.  Since fruit flies are model organisms, we can relate this to humans and find that low protein could yield the same results.  Fruit flies are found to share more than two thirds of disease genes with humans.  A mother’s diet can alter the risk of her offspring developing cardiovascular disease and diabetes later in life.  The study also looked at skin lipids that are released that can shorten lifespan.  These lipids were less toxic if the fly had a low protein diet at its early life.  Skin lipids would generally help flies as they prevent dehydration and stimulate courtship behaviors.  However, with added toxicity due to a high protein diet during development, they could end up shortening the lifespan of the flies.  Scientists found that the lipids didn’t only affect themselves, but nearby flies.  When many flies were placed together, their lifespan shortened due to the amount of toxic skin lipids.  Many of the genes involved in making skin lipids are conserved from flies to humans.

                Knowledge of these toxic skin lipids is alarming because they can react with sunlight and other stressors in the environment to produce harmful chemicals to accelerate the signs of aging in humans.  This study shows another reason why too much sunlight can be harmful.   It encourages me to wear more sunscreen and be wary of skin protection.  This study is important as it warns us about the dangers of a high protein diet at an early age.  Although flies are not exactly like humans, using model organisms for studies is a good way to get an idea about the subject.  An article from science direct shows how Drosophila makes a good model organism. 

 

https://www.sciencedaily.com/releases/2017/11/171109093258.htm

http://www.sciencedirect.com/science/article/pii/S1369702111701134

Drosophila effectively models human genes responsible for genetic kidney diseases

Genes associated with Nephrotic Syndrome (NS) in humans also plays a role in the Drosophila renal function, thus making Drosophila a ideal model to understand human disease. NS signals kidney damage symptoms include excess protein in urine, elevated cholesterol, swelling, and low protein in the blood. Researchers have found more than 40 different genes that can cause this specific genetic kidney disease, but gaps still remain in understanding the roles these genes play. Zhe Han a associate professor in the Center for Cancer and Immunology Research at Childrens National has begun studying the NS associated genes in Drosophila. Eighty-five percent of the genes required for kidney function in humans play a big role in flies. They can now be used to identify treatments for kidney disease and learn the function these genes play in the body. There is a need for more model organisms to study renal function. The renal system not only filters and eliminates waste but also indicates immune damage.  Using Drosophila as a model organism is quick, inexpensive , and relevant for this system of study.

https://www.sciencedaily.com/releases/2017/03/170317180606.htm

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3006309/

Why we sleep?

Of all the articles I have posted, this by far is the most interesting to me, because it is a topic in which I have high interest in? I came across an article which covers some hypothesis that seems credible and logical to me, on why we sleep. For years numerous of hypothesis were proposed on why we sleep but it isn't until now, scientist have propose an hypothesis that compliments common sense. The article reveals that we sleep to forget things--as the memory bank can only store a certain amount thus, when we sleep we forget something in order to make space to learn new things. https://www.nytimes.com/2017/02/02/science/sleep-memory-brain-forgetting.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=9&pgtype=sectionfront

http://www.sleepreviewmag.com/2017/02/purpose-sleep-forget-scientists-say/