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Australia’s A$60 million plan for Great Barrier Reef won’t work

Genetics - 6 hours 5 хв ago
The Australian government has pledged millions of dollars in extra funding to protect the Great Barrier Reef, but none of it will go to tackling the biggest threat
Категорії: Biology

Huge volcano eruption in the Philippines forces mass evacuation

Genetics - 8 hours 19 хв ago
More than 50,000 villagers were forced to flee their homes after the most active volcano in the Phillipines, Mount Mayon, spewed lava and ash plumes
Категорії: Biology

Huge volcano eruption in the Philippines forces mass evacuation

HIV and AIDS - 8 hours 19 хв ago
More than 50,000 villagers were forced to flee their homes after the most active volcano in the Phillipines, Mount Mayon, spewed lava and ash plumes
Категорії: Healthcare, Science and society

Huge volcano eruption in the Philippines forces mass evacuation

Genetically modified organisms (GMO) - 8 hours 19 хв ago
More than 50,000 villagers were forced to flee their homes after the most active volcano in the Phillipines, Mount Mayon, spewed lava and ash plumes
Категорії: Science and society

Tsunami warning for US west coast after magnitude-7.9 earthquake

Genetics - 9 hours 18 хв ago
A tsunami alert has been issued for the US west coast after a major earthquake struck at sea off the coast of Alaska
Категорії: Biology

Tsunami warning for US west coast after magnitude-7.9 earthquake

HIV and AIDS - 9 hours 18 хв ago
A tsunami alert has been issued for the US west coast after a major earthquake struck at sea off the coast of Alaska
Категорії: Healthcare, Science and society

Tsunami warning for US west coast after magnitude-7.9 earthquake

Genetically modified organisms (GMO) - 9 hours 18 хв ago
A tsunami alert has been issued for the US west coast after a major earthquake struck at sea off the coast of Alaska
Категорії: Science and society

Forgotten mountain shrine to a Soviet superstar of astrophysics

Genetics - 13 hours 5 хв ago
The Byurakan Astrophysical Observatory was founded by astrophysics pioneer Viktor Ambartsumian. Now its antiquated equipment is used to measure cosmic rays
Категорії: Biology

Forgotten mountain shrine to a Soviet superstar of astrophysics

Genetically modified organisms (GMO) - 13 hours 5 хв ago
The Byurakan Astrophysical Observatory was founded by astrophysics pioneer Viktor Ambartsumian. Now its antiquated equipment is used to measure cosmic rays
Категорії: Science and society

Evolution of mitotic spindle behavior during the first asymmetric embryonic division of nematodes

PLOS Biology (new articles) - 22 hours 5 хв ago

by Aurore-Cécile Valfort, Caroline Launay, Marie Sémon, Marie Delattre

Asymmetric cell division is essential to generate cellular diversity. In many animal cells, the cleavage plane lies perpendicular to the mitotic spindle, and it is the spindle positioning that dictates the size of the daughter cells. Although some properties of spindle positioning are conserved between distantly related model species and different cell types, little is known of the evolutionary robustness of the mechanisms underlying this event. We recorded the first embryonic division of 42 species of nematodes closely related to Caenorhabditis elegans, which is an excellent model system to study the biophysical properties of asymmetric spindle positioning. Our recordings, corresponding to 128 strains from 27 Caenorhabditis and 15 non-Caenorhabditis species (accessible at http://www.ens-lyon.fr/LBMC/NematodeCell/videos/), constitute a powerful collection of subcellular phenotypes to study the evolution of various cellular processes across species. In the present work, we analyzed our collection to the study of asymmetric spindle positioning. Although all the strains underwent an asymmetric first cell division, they exhibited large intra- and inter-species variations in the degree of cell asymmetry and in several parameters controlling spindle movement, including spindle oscillation, elongation, and displacement. Notably, these parameters changed frequently during evolution with no apparent directionality in the species phylogeny, with the exception of spindle transverse oscillations, which were an evolutionary innovation at the base of the Caenorhabditis genus. These changes were also unrelated to evolutionary variations in embryo size. Importantly, spindle elongation, displacement, and oscillation each evolved independently. This finding contrasts starkly with expectations based on C. elegans studies and reveals previously unrecognized evolutionary changes in spindle mechanics. Collectively, these data demonstrate that, while the essential process of asymmetric cell division has been conserved over the course of nematode evolution, the underlying spindle movement parameters can combine in various ways. Like other developmental processes, asymmetric cell division is subject to system drift.
Категорії: Biology, Journals

Unique properties of TCR-activated p38 are necessary for NFAT-dependent T-cell activation

PLOS Biology (new articles) - 22 hours 5 хв ago

by Muhammad S. Alam, Matthias M. Gaida, Subrata Debnath, Harichandra D. Tagad, Lisa M. Miller Jenkins, Ettore Appella, M. Jubayer Rahman, Jonathan D. Ashwell

Nuclear factor of activated T cells (NFAT) transcription factors are required for induction of T-cell cytokine production and effector function. Although it is known that activation via the T-cell antigen receptor (TCR) results in 2 critical steps, calcineurin-mediated NFAT1 dephosphorylation and NFAT2 up-regulation, the molecular mechanisms underlying each are poorly understood. Here we find that T cell p38, which is activated by an alternative pathway independent of the mitogen-activated protein (MAP) kinase cascade and with different substrate specificities, directly controls these events. First, alternatively (but not classically) activated p38 was required to induce the expression of the AP-1 component c-Fos, which was necessary for NFAT2 expression and cytokine production. Second, alternatively (but not classically) activated p38 phosphorylated NFAT1 on a heretofore unidentified site, S79, and in its absence NFAT1 was unable to interact with calcineurin or migrate to the nucleus. These results demonstrate that the acquisition of unique specificities by TCR-activated p38 orchestrates NFAT-dependent T-cell functions.
Категорії: Biology, Journals

Identification of osmoadaptive strategies in the halophile, heterotrophic ciliate <i>Schmidingerothrix salinarum</i>

PLOS Biology (new articles) - 22 hours 5 хв ago

by Lea Weinisch, Steffen Kühner, Robin Roth, Maria Grimm, Tamara Roth, Daili J. A. Netz, Antonio J. Pierik, Sabine Filker

Hypersaline environments pose major challenges to their microbial residents. Microorganisms have to cope with increased osmotic pressure and low water activity and therefore require specific adaptation mechanisms. Although mechanisms have already been thoroughly investigated in the green alga Dunaliella salina and some halophilic yeasts, strategies for osmoadaptation in other protistan groups (especially heterotrophs) are neither as well known nor as deeply investigated as for their prokaryotic counterpart. This is not only due to the recent awareness of the high protistan diversity and ecological relevance in hypersaline systems, but also due to methodological shortcomings. We provide the first experimental study on haloadaptation in heterotrophic microeukaryotes, using the halophilic ciliate Schmidingerothrix salinarum as a model organism. We established three approaches to investigate fundamental adaptation strategies known from prokaryotes. First, hydrogen-1 nuclear magnetic resonance (1H-NMR) spectroscopy was used for the detection, identification, and quantification of intracellular compatible solutes. Second, ion-imaging with cation-specific fluorescent dyes was employed to analyze changes in the relative ion concentrations in intact cells. Third, the effect of salt concentrations on the catalytic performance of S. salinarum malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICDH) was determined. 1H-NMR spectroscopy identified glycine betaine (GB) and ectoine (Ect) as the main compatible solutes in S. salinarum. Moreover, a significant positive correlation of intracellular GB and Ect concentrations and external salinity was observed. The addition of exogenous GB, Ect, and choline (Ch) stimulated the cell growth notably, indicating that S. salinarum accumulates the solutes from the external medium. Addition of external 13C2-Ch resulted in conversion to 13C2-GB, indicating biosynthesis of GB from Ch. An increase of external salinity up to 21% did not result in an increase in cytoplasmic sodium concentration in S. salinarum. This, together with the decrease in the catalytic activities of MDH and ICDH at high salt concentration, demonstrates that S. salinarum employs the salt-out strategy for haloadaptation.
Категорії: Biology, Journals

Hippo signaling controls cell cycle and restricts cell plasticity in planarians

PLOS Biology (new articles) - 22 hours 5 хв ago

by Nídia de Sousa, Gustavo Rodríguez-Esteban, Jose Ignacio Rojo-Laguna, Emili Saló, Teresa Adell

The Hippo pathway plays a key role in regulating cell turnover in adult tissues, and abnormalities in this pathway are consistently associated with human cancers. Hippo was initially implicated in the control of cell proliferation and death, and its inhibition is linked to the expansion of stem cells and progenitors, leading to larger organ size and tumor formation. To understand the mechanism by which Hippo directs cell renewal and promotes stemness, we studied its function in planarians. These stem cell–based organisms are ideal models for the analysis of the complex cellular events underlying tissue renewal in the whole organism. hippo RNA interference (RNAi) in planarians decreased apoptotic cell death, induced cell cycle arrest, and could promote the dedifferentiation of postmitotic cells. hippo RNAi resulted in extensive undifferentiated areas and overgrowths, with no effect on body size or cell number. We propose an essential role for hippo in controlling cell cycle, restricting cell plasticity, and thereby preventing tumoral transformation.
Категорії: Biology, Journals

Spy balloons flying 40km up track drug smugglers on the ground

Genetics - Пн, 2018-01-22 20:03
The US military are testing uncrewed, hydrogen-filled balloons that can keep watch over a small area by catching different winds in the stratosphere
Категорії: Biology

Spy balloons flying 40km up track drug smugglers on the ground

HIV and AIDS - Пн, 2018-01-22 20:03
The US military are testing uncrewed, hydrogen-filled balloons that can keep watch over a small area by catching different winds in the stratosphere
Категорії: Healthcare, Science and society

Spy balloons flying 40km up track drug smugglers on the ground

Genetically modified organisms (GMO) - Пн, 2018-01-22 20:03
The US military are testing uncrewed, hydrogen-filled balloons that can keep watch over a small area by catching different winds in the stratosphere
Категорії: Science and society

AI that cracked ancient secret code could help robot translation

Genetics - Пн, 2018-01-22 19:46
Breaking ciphers is like learning to translate a language, so a technique that unscrambled one of the earliest known examples could assist machine translation
Категорії: Biology

AI that cracked ancient secret code could help robot translation

HIV and AIDS - Пн, 2018-01-22 19:46
Breaking ciphers is like learning to translate a language, so a technique that unscrambled one of the earliest known examples could assist machine translation
Категорії: Healthcare, Science and society

AI that cracked ancient secret code could help robot translation

Genetically modified organisms (GMO) - Пн, 2018-01-22 19:46
Breaking ciphers is like learning to translate a language, so a technique that unscrambled one of the earliest known examples could assist machine translation
Категорії: Science and society

Cute cats the size of kittens are seeing their homes destroyed

Genetics - Пн, 2018-01-22 19:20
Güiñas are the smallest cats in the Americas, smaller than most domestic cats, and they are becoming increasingly rare
Категорії: Biology