Why are RNA virus mutation rates so damn high?

PLOS Biology (new articles) - 12 hours 46 хв ago

by Siobain Duffy

The high mutation rate of RNA viruses is credited with their evolvability and virulence. This Primer, however, discusses recent evidence that this is, in part, a byproduct of selection for faster genomic replication.
Категорії: Biology, Journals

Evolutionary diversification of the HAP2 membrane insertion motifs to drive gamete fusion across eukaryotes

PLOS Biology (new articles) - 12 hours 46 хв ago

by Juliette Fedry, Jennifer Forcina, Pierre Legrand, Gérard Péhau-Arnaudet, Ahmed Haouz, Mark Johnson, Felix A. Rey, Thomas Krey

HAPLESS2 (HAP2) is a broadly conserved, gamete-expressed transmembrane protein that was shown recently to be structurally homologous to viral class II fusion proteins, which initiate fusion with host cells via insertion of fusion loops into the host membrane. However, the functional conformation of the HAP2 fusion loops has remained unknown, as the reported X-ray structure of Chlamydomonas reinhardtii HAP2 lacked this critical region. Here, we report a structure-guided alignment that reveals diversification of the proposed HAP2 fusion loops. Representative crystal structures show that in flowering plants, HAP2 has a single prominent fusion loop projecting an amphipathic helix at its apex, while in trypanosomes, three small nonpolar loops of HAP2 are poised to interact with the target membrane. A detailed structure-function analysis of the Arabidopsis HAP2 amphipathic fusion helix defines key residues that are essential for membrane insertion and for gamete fusion. Our study suggests that HAP2 may have evolved multiple modes of membrane insertion to accommodate the diversity of membrane environments it has encountered during eukaryotic evolution.
Категорії: Biology, Journals

Provenance and risk in transfer of biological materials

PLOS Biology (new articles) - 12 hours 46 хв ago

by Jane Nielsen, Tania Bubela, Don R. C. Chalmers, Amber Johns, Linda Kahl, Joanne Kamens, Charles Lawson, John Liddicoat, Rebekah McWhirter, Ann Monotti, James Scheibner, Tess Whitton, Dianne Nicol

Whereas biological materials were once transferred freely, there has been a marked shift in the formalisation of exchanges involving these materials, primarily through the use of Material Transfer Agreements (MTAs). This paper considers how risk aversion dominates MTA negotiations and the impact it may have on scientific progress. Risk aversion is often based on unwarranted fears of incurring liability through the use of a material or loss of control or missing out on commercialisation opportunities. Evidence to date has suggested that complexity tends to permeate even straightforward transactions despite extensive efforts to implement simple, standard MTAs. We argue that in most cases, MTAs need do little more than establish provenance, and any attempt to extend MTAs beyond this simple function constitutes stifling behaviour. Drawing on available examples of favourable practice, we point to a number of strategies that may usefully be employed to reduce risk-averse tendencies, including the promotion of simplicity, education of those engaged in the MTA process, and achieving a cultural shift in the way in which technology transfer office (TTO) success is measured in institutions employing MTAs.
Категорії: Biology, Journals

Cybersecurity is failing us – and will continue to do so unless we act

Genetics - Пн, 2018-08-13 12:00
Our current model of internet security is too vulnerable to the mistakes of individual programmers. Better alternatives exist – and should be deployed
Категорії: Biology

Buzz: A beautiful book shows why modern bees are hippy wasps at heart

Genetics - Пн, 2018-08-13 11:00
A beautifully illustrated new book details the evolutionary path that created modern bees from their ancient wasp ancestors - and why the apians’ future is uncertain
Категорії: Biology

Tools reveal Easter Island may not have had a societal collapse

Genetics - Пн, 2018-08-13 07:00
Tools used to make Easter Island’s famous statues have yielded a clue that suggests the Rapa Nui inhabitants that made them all got along with each other
Категорії: Biology

Don’t miss: Taxidermied rabbits, mucky biology and the digital future

Genetics - Сб, 2018-08-11 16:00
See a taxidermied rabbit in a silver goblet at show about human-animal hybrids, read about biology's muckier side, and listen to tough talk about our digital future
Категорії: Biology

Heterogeneity and longevity of antibody memory to viruses and vaccines

PLOS Biology (new articles) - Пт, 2018-08-10 23:00

by Alice Antia, Hasan Ahmed, Andreas Handel, Nichole E. Carlson, Ian J. Amanna, Rustom Antia, Mark Slifka

Determining the duration of protective immunity requires quantifying the magnitude and rate of loss of antibodies to different virus and vaccine antigens. A key complication is heterogeneity in both the magnitude and decay rate of responses of different individuals to a given vaccine, as well as of a given individual to different vaccines. We analyzed longitudinal data on antibody titers in 45 individuals to characterize the extent of this heterogeneity and used models to determine how it affected the longevity of protective immunity to measles, rubella, vaccinia, tetanus, and diphtheria. Our analysis showed that the magnitude of responses in different individuals varied between 12- and 200-fold (95% coverage) depending on the antigen. Heterogeneity in the magnitude and decay rate contribute comparably to variation in the longevity of protective immunity between different individuals. We found that some individuals have, on average, slightly longer-lasting memory than others—on average, they have higher antibody levels with slower decay rates. We identified different patterns for the loss of protective levels of antibodies to different vaccine and virus antigens. Specifically, we found that for the first 25 to 50 years, virtually all individuals have protective antibody titers against diphtheria and tetanus, respectively, but about 10% of the population subsequently lose protective immunity per decade. In contrast, at the outset, not all individuals had protective titers against measles, rubella, and vaccinia. However, these antibody titers wane much more slowly, with a loss of protective immunity in only 1% to 3% of the population per decade. Our results highlight the importance of long-term longitudinal studies for estimating the duration of protective immunity and suggest both how vaccines might be improved and how boosting schedules might be reevaluated.
Категорії: Biology, Journals

A non-cell-autonomous actin redistribution enables isotropic retinal growth

PLOS Biology (new articles) - Пт, 2018-08-10 23:00

by Marija Matejčić, Guillaume Salbreux, Caren Norden

Tissue shape is often established early in development and needs to be scaled isotropically during growth. However, the cellular contributors and ways by which cells interact tissue-wide to enable coordinated isotropic tissue scaling are not yet understood. Here, we follow cell and tissue shape changes in the zebrafish retinal neuroepithelium, which forms a cup with a smooth surface early in development and maintains this architecture as it grows. By combining 3D analysis and theory, we show how a global increase in cell height can maintain tissue shape during growth. Timely cell height increase occurs concurrently with a non-cell-autonomous actin redistribution. Blocking actin redistribution and cell height increase perturbs isotropic scaling and leads to disturbed, folded tissue shape. Taken together, our data show how global changes in cell shape enable isotropic growth of the developing retinal neuroepithelium, a concept that could also apply to other systems.
Категорії: Biology, Journals

Transcriptional programming of lipid and amino acid metabolism by the skeletal muscle circadian clock

PLOS Biology (new articles) - Пт, 2018-08-10 23:00

by Kenneth Allen Dyar, Michaël Jean Hubert, Ashfaq Ali Mir, Stefano Ciciliot, Dominik Lutter, Franziska Greulich, Fabiana Quagliarini, Maximilian Kleinert, Katrin Fischer, Thomas Oliver Eichmann, Lauren Emily Wright, Marcia Ivonne Peña Paz, Alberto Casarin, Vanessa Pertegato, Vanina Romanello, Mattia Albiero, Sara Mazzucco, Rosario Rizzuto, Leonardo Salviati, Gianni Biolo, Bert Blaauw, Stefano Schiaffino, N. Henriette Uhlenhaut

Circadian clocks are fundamental physiological regulators of energy homeostasis, but direct transcriptional targets of the muscle clock machinery are unknown. To understand how the muscle clock directs rhythmic metabolism, we determined genome-wide binding of the master clock regulators brain and muscle ARNT-like protein 1 (BMAL1) and REV-ERBα in murine muscles. Integrating occupancy with 24-hr gene expression and metabolomics after muscle-specific loss of BMAL1 and REV-ERBα, here we unravel novel molecular mechanisms connecting muscle clock function to daily cycles of lipid and protein metabolism. Validating BMAL1 and REV-ERBα targets using luciferase assays and in vivo rescue, we demonstrate how a major role of the muscle clock is to promote diurnal cycles of neutral lipid storage while coordinately inhibiting lipid and protein catabolism prior to awakening. This occurs by BMAL1-dependent activation of Dgat2 and REV-ERBα-dependent repression of major targets involved in lipid metabolism and protein turnover (MuRF-1, Atrogin-1). Accordingly, muscle-specific loss of BMAL1 is associated with metabolic inefficiency, impaired muscle triglyceride biosynthesis, and accumulation of bioactive lipids and amino acids. Taken together, our data provide a comprehensive overview of how genomic binding of BMAL1 and REV-ERBα is related to temporal changes in gene expression and metabolite fluctuations.
Категорії: Biology, Journals

Gluten-free dogs? Pets deserve better than this evidence-free fad

Genetics - Пт, 2018-08-10 18:35
Animal owners are increasingly falling for potentially risky fad pet diets or homeopathic alternatives to vaccines, warn vets Danny Chambers and Zoe Belshaw
Категорії: Biology

Fortnite is coming to Android, but players risk downloading malware

Genetics - Пт, 2018-08-10 17:14
When blockbuster game Fortnite hits Android phones, gamers will be able to get it outside Google Play, which could leave them vulnerable to scams
Категорії: Biology

Preserved ocean creatures make landfall in London

Genetics - Пт, 2018-08-10 17:00
Dissected and preserved sea life specimens give visitors a thrilling, slightly shallow glimpse of a hidden world
Категорії: Biology

Bots on Amazon’s Mechanical Turk are ruining psychology studies

Genetics - Пт, 2018-08-10 14:26
Psychologists use Amazon’s Mechanical Turk platform to study our behaviour, but now bots are spoiling things by pretending to be human
Категорії: Biology

This man spent months alone underground – and it warped his mind

Genetics - Пт, 2018-08-10 14:00
Michel Siffre’s extraordinary self-experiments in a cave with no light would never be allowed now – but revealed strange truths about how we perceive time
Категорії: Biology

The Meg: Real Megalodon shark would eat Jason Statham for breakfast

Genetics - Пт, 2018-08-10 13:37
Jason Statham’s new film The Meg looks gloriously silly and good luck to it, but it got us thinking about what its giant prehistoric shark was really like and why it died out
Категорії: Biology

New Scientist Live: sneak preview of this year’s mission to Mercury

Genetics - Пт, 2018-08-10 13:31
It’s time to return to the planet Mercury. At New Scientist Live, Emma Bunce will be revealing all about the BepiColombo mission set to launch in October
Категорії: Biology

New Zealand becomes the latest country to ban plastic bags

Genetics - Пт, 2018-08-10 13:05
People in New Zealand currently use about 150 plastic bags each a year, but the country now plans to phase them out within the next six months
Категорії: Biology

Feedback: What would happen if Earth was made of blueberries?

Genetics - Пт, 2018-08-10 12:00
Thanks to science, we now have an answer. Plus: a stolen shark, mapping the Kessel Run, TripAdvisor reviews of migrating animals, and more
Категорії: Biology

Allergy explosion: What causes allergies and how to avoid them

Genetics - Пт, 2018-08-10 11:00
We've all heard that being too clean can cause allergies, or exposure can help you beat them. Most advice doesn't stand up, but there are things that do seem to work
Категорії: Biology