A tale of survival

How fish were able to colonize poisonous springs

2014-05-13

(Press-News.org) Frankfurt am Main, Germany, May 12, 2014. Hydrogen sulphide (H2S) is a potent inhibitor of aerobic respiration. However populations of shortfin molly fish managed to colonise springs with high concentrations of dissolved hydrogen sulphide. In a new study researchers from LOEWE Biodiversity and Climate Research Centre (BiK-F) and the Goethe University Frankfurt present evidence of genetic changes minimizing the harmful effects of H2S which enable the fish to survive in this deleterious environment. The study provides insight into the molecular mechanisms of this key adaptation for the first time. It is published online today in "Nature Communications".

Shortfin molly fishes (Poecilia mexicana) may only measure a few inches, but they are still exceptional. Populations of Poecilia mexicana, whose relatives are the well-known guppy, colonised sulphide-rich volcanic springs in Southern Mexico. In making this particular habitat their home, they have made the impossible possible, because hydrogen sulphide (H2S), as for many other animal, is lethal. Even at low concentrations the gas blocks the cytochrome c oxidase-complex (COX). The higher the level of hydrogen sulphide, the more the activity of COX is inhibited. As it is essential for respiration, this turns out to be lethal in the end.

Changes in genetic make-up make less susceptible to poison A team led by Prof. Dr. Markus Pfenninger, LOEWE Biodiversity and Climate Research Centre (BiK-F) and PD Dr. Martin Plath, Goethe University, has taken a closer look at the survivors. Their analysis showed that the COX activity of individuals of shortfin molly fish which colonise H2S-rich waters remains virtually unchanged under high H2S concentrations. This is due to a number of changes in the cox1 and cox3 genes, which have only occurred in populations living in the poisonous springs. Thus, transplanting individuals from non-sulphidic habitat to springs with high H2S levels kills them for sure.

Molecular mechanisms of adaptation to extreme habitat "In this paper we analyse the key adaptation to an extreme habitat up to its mo-lecular basis at the level of amino acids. This way, for the first time, we are able to point out, where exactly the adaption has taken place." Pfenninger concludes. The team also modelled three dimensional protein structures in order to shed light on necessary significant structural changes of amino acids in the cox1 gene. Without these structural changes, the colonisation of the H2S-containing water for the fish would have been impossible. By colonising the poisonous springs, where there are hardly any other competitors, the fish may feed on resistant midge larvae that also occur there.

Closely related fish follow different paths to adaptation The study also shows that closely related populations of a species follow parallel as well as disparate paths in response to similar environmental conditions. Three shortfin molly fish populations were sampled for study. Two of the populations show the same changes in their genetic material in adapting to the hostile conditions. However this proved to be not the case for the third population of shortfin molly fish. Whereas these fish also tolerate high levels hydrogen sulphide, the mechanism enabling their adaptation is still subject to ongoing research.

INFORMATION: Paper: Pfenninger, M. et al.: Parallel evolution of cox-genes in H2S- tolerant fish as key adaptation to a toxic environment – Nature Communications, DOI: 10.1038/ncomms4873

For more information please contact: Prof. Dr. Markus Pfenninger
Goethe University &
LOEWE Biodiversity and Climate Research Centre (BiK-F)
Tel. +49 (0)69 7542 1841
Pfenninger@bio.uni-frankfurt.de

or Sabine Wendler
LOEWE Biodiversity and Climate Research Centre (BiK-F)
Press officer
Tel. +49 (0)69 7542 1838
Sabine.wendler@senckenberg.de

ELSE PRESS RELEASES FROM THIS DATE:

Bird invaders 'moving in' to UK's nature reserves

2014-05-13

A new study by scientists at the University of York and the RSPB Centre for Conservation Science has demonstrated that nature reserves and other areas specially protected for wildlife, as well as being vital for native species, are very important for helping European birds to expand their ranges into Britain naturally. The catch is that protected areas are also at increasing risk of invasion by species that have been introduced from further afield. The research, published in the journal Diversity and Distributions, explores how the UK's special places for nature have ...

Comet theory false; doesn't explain Ice Age cold snap, Clovis changes, animal extinction

2014-05-13

Controversy over what sparked the Younger Dryas, a brief return to near glacial conditions at the end of the Ice Age, includes a theory that it was caused by a comet hitting the Earth. As proof, proponents point to sediments containing deposits they believe could result only from a cosmic impact. Now a new study disproves that theory, said archaeologist David Meltzer, Southern Methodist University, Dallas. Meltzer is lead author on the study and an expert in the Clovis culture, the peoples who lived in North America at the end of the Ice Age. Meltzer's research team ...

Chemists design molecules for controlling bacterial behavior

2014-05-13

Chemists in the College of Arts and Sciences have figured out how to control multiple bacterial behaviors—potentially good news for the treatment of infectious diseases and other bacteria-associated issues, without causing drug resistance. Yan-Yeung Luk, associate professor of chemistry, has spearheaded the discovery, in conjunction with his research lab at Syracuse University and the Wang Lab at SUNY Upstate Medical University. Their findings are the subject of a forthcoming article in the journal ChemBioChem (John Wiley & Sons Inc.). "Since the discovery of the first ...

UCSF: E-cigarettes expose people to more than harmless vapor, should be regulated

2014-05-13

In a major scientific review of research on e-cigarettes, UC San Francisco scientists found that industry claims about the devices are unsupported by the evidence to date, including claims that e-cigarettes help smokers quit. The review marks the first comprehensive assessment of peer-reviewed published research into the relatively new phenomenon of electronic cigarettes. The devices, which are rapidly gaining a foothold in popular culture particularly among youth, are marketed as a healthier alternative to tobacco smoking, as an effective tool to stop smoking, ...

Scientists from USC and NYU design a molecule that blocks cancer growth in mice

2014-05-13

A team of researchers from USC and NYU has developed and patented a small molecule that interferes with cancer progression with minimal side effects. The molecule prevents two critical proteins from interacting by mimicking the surface topography of one protein – like wearing a mask – which tricks the other protein into binding with it. This stops a so-called "transcription factor" that controls the transcription of genetic information. That transcription factor is what would have created an aberrant gene expression, contributing to the cancer growth. Because of the ...

Scientists slow brain tumor growth in mice

2014-05-13

Much like using dimmer switches to brighten or darken rooms, biochemists have identified a protein that can be used to slow down or speed up the growth of brain tumors in mice. Brain and other nervous system cancers are expected to claim 14,320 lives in the United States this year. The results of the preclinical study led by Eric J. Wagner, Ph.D., and Ann-Bin Shyu, Ph.D., of The University of Texas Health Science Center at Houston (UTHealth) and Wei Li, Ph.D., of Baylor College of Medicine appear in the Advance Online Publication of the journal Nature. "Our work ...

Birth by C-section, early antibiotic use put kids at risk for allergic esophagitis

2014-05-13

Children delivered by cesarean section and those given antibiotics during early infancy appear more prone to developing allergic inflammation of the esophagus — the muscular tube that connects the mouth to the stomach — according to results of a study by investigators from the Johns Hopkins Children's Center and Harvard Medical School. The findings, published online May 2 in the Journal of Allergy and Clinical Immunology: In Practice, reveal that early antibiotic treatment and C-section delivery may somehow precipitate disease development by altering a child's microbiota ...

Professional surfer back in the water after successful surgery to treat rare bone cancer

2014-05-13

LOS ANGELES (May 13, 2014) – When professional surfer Richie Lovett began experiencing hip pain at 31, he attributed it to his athletic lifestyle. But after months of discomfort and preliminary tests, the Australian native learned the pain was caused by a cancerous tumor in his femur or thigh bone. "As a professional athlete, I was blindsided by the news that I had cancer," said Lovett. "I realized very quickly that cancer would have a profound effect on my life. I knew I needed an experienced oncologist to tackle this disease, so I began an international search to find ...

Quantum trimer -- from a distance

2014-05-13

Eight years ago Rudolf Grimm's research group was the first to observe an Efimov state in an ultracold quantum gas. The Russian physicist Vitali Efimov theoretically predicted this exotic bound state of three particles in the 1970s. He forecast that three particles would form a bound state due to their quantum mechanical properties, under conditions when a two-body bound state would be absent. What is even more astounding: When the distance between the particles is increased by factor 22.7, another Efimov state appears, leading to an infinite series of these states. Until ...

Researchers identify link between colon cancer and metabolism

2014-05-13

HEIDELBERG, 13 May 2014 – More than 60 years ago Otto Warburg recognized that cancer cells differ from normal cells in the metabolic pathway they use for the oxidation of sugar. Rather than the typical series of oxidative steps that take place in the citric acid cycle, cancer cells metabolize sugar via the glycolytic pathway irrespective of whether oxygen is present or not. In The EMBO Journal, researchers in the United States report that the reason for this difference in colon cancer is changes in the Wnt signaling pathway, an essential communication pathway operating ...

DARPA-ABC program supports Wyss Institute-led collaboration toward deeper understanding of anesthesia and safe drugs enabling anesthesia without the need for extensive monitoring

Davos Alzheimer's Collaborative launches innovative brain health navigator program for intuitive coordination between patients and providers

Large-scale TMIST breast cancer screening trial achieves enrollment goal, paving the way for data that provides a precision approach to screeninge

Study published in NEJM Catalyst finds patients cared for by MedStar Health’s Safe Babies Safe Moms program have better outcomes in pregnancy, delivery, and postpartum

A tale of survival

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: