Scientists wipe out malaria-carrying mosquitoes in the lab by creating male-only offspring

Scientists have modified mosquitoes to produce sperm that will only create males, pioneering a fresh approach to eradicating malaria.

In a study published in the journal Nature Communications, scientists from Imperial College London have tested a new genetic method that distorts the sex ratio of Anopheles gambiae mosquitoes, the main transmitters of the malaria parasite, so that the female mosquitoes that bite and pass the disease to humans are no longer produced.

In the first laboratory tests, the method created a fully fertile mosquito strain that produced 95 per cent male offspring.

Continue reading “Scientists wipe out malaria-carrying mosquitoes in the lab by creating male-only offspring”

From friend to foe: How benign bacteria evolve to virulent pathogens

Contact: Isabel Gordo igordo@igc.gulbenkian.pt 351-214-407-915 Public Library of Science

Bacteria can evolve rapidly to adapt to environmental change. When the “environment” is the immune response of an infected host, this evolution can turn harmless bacteria into life-threatening pathogens. A study published on December 12 in PLOS Pathogens provides insight into how this happens.

Isabel Gordo and colleagues from the Instituto Gulbenkian de Ciencia in Oeira, Portugal, have for the first time devised an experimental system to observe and study the evolution of bacteria in response to encounters with cells of the mammalian immune system. They found that in less than 500 bacterial generations (or 30 days), the bacteria became more resistant to being killed by immune cells and acquired the ability to cause disease in mice. Continue reading “From friend to foe: How benign bacteria evolve to virulent pathogens”

Viruses cooperate or conquer to cause maximum destruction: They Change Behaviour to overcome our attempt to control them

Contact: Louise Vennells L.Vennells@exeter.ac.uk 44-013-927-22062 University of Exeter

Scientists have discovered new evidence about the evolution of viruses, in work that will change our understanding about the control of infectious diseases such as winter flu

Scientists have discovered new evidence about the evolution of viruses, in work that will change our understanding about the control of infectious diseases such as winter flu.

Researchers at the University of Exeter’s conducted experiments to manipulate a virus to see if it could evolve the ability to switch its behaviour according to how many other viruses infect a host.

Previous research has focussed on trying to force harmful microbes to become less threatening to human health as they evolve. But the new research, which was carried out in collaboration with the University of Oxford, proves viruses can readily develop the ability to adjust their behaviour to maximise their spread, in response to whether they are infecting as a single entity or in combination with other viruses.

Helen Leggett, a postgraduate researcher at the University of Exeter, was the lead scientist on the work, which is published online on December 13th in the journal Current Biology. She said: “Scientists are constantly searching for ways to limit the damage viruses can cause, to help reduce the impact of illnesses like winter flu and to respond to the next pandemic. Our work proves that regardless of how we try to manipulate viruses, they will always switch their behaviour to serve their own purposes and kill as many cells as possible. This study involved a relatively simple virus. If it can evolve so quickly, it’s reasonable to assume that a lot of other viruses and parasites can, too.”

The study was funded by the European Research Council, the Leverhulme Trust and the Natural Environment Research Council, while Helen Leggett is supported by the Biotechnology and Biological Sciences Research Council. The work also shed light on why organisms cooperate with each other. The virus would only cooperate with viruses which were related to it. When it infected alone it would clone itself within the cell, and would cooperate with those new viruses. In this context, cooperation meant killing the host relatively slowly so that the virus could replicate more.  But when it interacted with other viruses which were not related, it killed the cell faster, allowing it to out-replicate and dominate the other viruses.

Grapefruit’s bitter taste holds a sweet promise for diabetes therapy

2010 study posted for filing

Contact: Jen Laloup jlaloup@plos.org 415-624-1220 Public Library of Science

Naringenin, an antioxidant derived from the bitter flavor of grapefruits and other citrus fruits, may cause the liver to break down fat while increasing insulin sensitivity, a process that naturally occurs during long periods of fasting.

A team of researchers from the Hebrew University of Jerusalem and Massachusetts General Hospital (MGH) report that naringenin activates a family of small proteins, called nuclear receptors, causing the liver to break down fatty acids. In fact, the compound seems to mimic the actions of other drugs, such as the lipid-lowering Fenofibrate and the anti-diabetic Rosiglitazone, offering the advantages of both. If the results of this study extend to human patients, this dietary supplement could become a staple in the treatment of hyperlipidemia, type-2 diabetes, and perhaps metabolic syndrome. The report appears in this week issue of the online journal PLoS ONE.

“It is a fascinating find,” says Yaakov Nahmias, PhD, of the Hebrew University of Jerusalem the paper’s senior author. “We show the mechanism by which naringenin increases two important pharmaceutical targets, PPARα and PPARγ, while blocking a third, LXRα. The results are similar to those induced by long periods of fasting”.

The liver is the main organ responsible for the regulation of carbohydrate and lipid levels in the blood. Following a meal, the blood is flushed with sugars, which activate LXRα, causing the liver to create fatty acids for long-term storage. During fasting, the process is reversed; fatty acids are released by fat cells, activate PPARα in the liver, and are broken down to ketones.  A similar process, involving PPARγ, increases sensitivity to insulin.

“It is a process which is similar to the Atkins diet, without many of the side effects,” says Martin L. Yarmush, MD, PhD, director of the MGH Center for Engineering in Medicine and one of the paper’s authors.

“The liver behaves as if fasting, breaking down fatty acids instead of carbohydrates.” Yarmush is the Helen Andrus Benedict Professor of Surgery and Bioengineering at Harvard Medical School.

“Dual PPARα and PPARγ agonists, like naringenin, were long sought after by the pharmaceutical industry,” says Nahmias, “but their development was plagued by safety concerns. Remarkably, naringenin is a dietary supplement with a clear safety record. Evidence suggests it might actually protect the liver from damage.”

Grapefruit’s bitter taste is caused the presence of the flavonoid naringin, which is broken down in the gut into naringenin. Earlier evidence has shown the compound has cholesterol lowering properties and may ameliorate some of the symptoms associated with diabetes. The researchers demonstrated that the compound activates PPARα and PPARγ by dramatically increasing the levels of a co-activator peptide of both, called PGC1α. At the same time, naringenin bound directly to LXRα, blocking its activation. These effects culminated with increased fatty acid oxidation and the inhibition of vLDL (‘bad cholesterol’) production.

###

 

Additional co-authors of the PLoS ONE paper are Jonathan Goldwasser, PhD, Eric Yang, PhD, MGH; Pazit Cohen, PhD, Hebrew University; and Patrick Balaguer, PhD, INSERM Univ. Montpellier France. The work was supported by grants from the National Institutes of Health (NIH) and European Research Council (ERC).

Citation: Goldwasser J, Cohen PY, Yang E, Balaguer P, Yarmush ML, et al. (2010) Transcriptional Regulation of Human and Rat Hepatic Lipid Metabolism by the Grapefruit Flavonoid Naringenin: Role of PPARa, PPARc and LXRa. PLoS ONE 5(8): e12399. doi:10.1371/journal.pone.0012399

Competing Interests: The authors have declared that no competing interests exist.

Funding: This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases (K01DK080241), a European Research Council starting grant (TMIHCV 242699), and the Harvard Clinical Nutrition Research Center (P30-DK040561). Resources were provided by the BioMEMS Resource Center (P41 EB-002503), Shriners Burns Hospital, and the Alexander Silberman Institute of Life Sciences. The funders had no role in study design, data collection and analysis,decision to publish, or preparation of the manuscript.

PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends): http://dx.plos.org/10.1371/journal.pone.0012399

FOR A PRESS-ONLY PREVIEW OF THE FULL ARTICLE, VISIT THE FOLLOWING URL: http://www.plos.org/press/pone-05-08-nahmias.pdf

Disclaimer

This press release refers to upcoming articles in PLoS ONE. The releases have been provided by the article authors and/or journal staff. Any opinions expressed in these are the personal views of the contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the release and article and your use of such information.

About PLoS ONE

PLoS ONE is the first journal of primary research from all areas of science to employ a combination of peer review and post-publication rating and commenting, to maximize the impact of every report it publishes. PLoS ONE is published by the Public Library of Science (PLoS), the open-access publisher whose goal is to make the world’s scientific and medical literature a public resource.

Tenth of Quirky Creature’s Active Genes Are Foreign: Believed to ‘Ingest’ DNA from Other Simple Organisms

Bdelloid rotifer. Alan Tunnacliffe said: “We were thrilled when we discovered that nearly 10 per cent of bdelloids’ active genes are foreign, adding to the weirdness of an already odd little creature.” (Credit: Image courtesy of University of Cambridge)

ScienceDaily (Nov. 15, 2012) — Up to 10 per cent of the active genes of an organism that has survived 80 million years without sex are foreign, a new study from the University of Cambridge and Imperial College London reveals. The asexual organism, the bdelloid rotifer, has acquired a tenth of its active genes from bacteria and other simple organisms like fungi and algae.

The findings were reported Nov. 15 in the journal PLoS Genetics.

Bdelloid rotifers are best known for going 80 million years without sex, as they have evolved to reproduce successfully without males. Many asexual creatures go extinct without the benefit of traditional genetic evolution. However, bdelloids have flourished by developing ingenious ways of overcoming the limitations of being asexual.

Bdelloids have also developed the fascinating ability to withstand almost complete desiccation when the freshwater pools they typically live in dry up. They can survive in the dry state for many years only to revive with no ill effect once water becomes available again.

“We were thrilled when we discovered that nearly 10 per cent of bdelloids’ active genes are foreign, adding to the weirdness of an already odd little creature,” said Professor Alan Tunnacliffe, lead author of the study from the University of Cambridge. “We don’t know how the gene transfer occurs, but it almost certainly involves ingesting DNA in organic debris, which their environments are full of. Bdelloids will eat anything smaller than their heads!”

Because some of the foreign genes are activated when the bdelloids begin to dry out, the researchers believe that the genes play a role in bdelloids’ ability to survive desiccation.

Professor Tunnacliffe added: “Other researchers have shown that bdelloids contain powerful antioxidants, which help protect them from the toxic oxidising agents that are the by-products of desiccation. These antioxidants have not yet been identified, but we think that some of them result from foreign genes.”

For the study, the researchers extracted all of the messenger RNA (genetic code similar to DNA which provides a blueprint for the creation of proteins) from bdelloid rotifers and sequenced each message, creating a library of the animal’s active coding information. Using a supercomputer, they then compared these messages with all other known sequences and found that in many cases similar sequences had been found in other organisms.

Strangely, however, these other organisms were often not animals, but simple microbes. This means that bdelloids have genes that are not present in other animals, but have been acquired from micro-organisms and adapted for use in the rotifer.

The research was funded by the Biotechnology and the Biological Sciences Research Council (BBSRC) and the European Research Council.

http://www.sciencedaily.com/releases/2012/11/121115172032.htm