The envelope protein E of the SARS-CoV coronavirus is an archetype of viroporin. It is a small hydrophobic protein displaying ion channel activity that has proven highly relevant in virus-host interaction and virulence. Ion transport through E channel was shown to alter Ca2+ homeostasis in the cell and trigger inflammation processes. Here, we study transport properties of the E viroporin in mixed solutions of potassium and calcium chloride that contain a fixed total concentration (mole fraction experiments). The channel is reconstituted in planar membranes of different lipid compositions, including a lipid mixture that mimics the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) membrane where the virus localizes within the cell. We find that the E ion conductance changes non-monotonically with the total ionic concentration displaying an Anomalous Mole Fraction Effect (AMFE) only when charged lipids are present in the membrane. We also observe that E channel insertion in ERGIC-mimic membranes - including lipid with intrinsic negative curvature - enhances ion permeation at physiological concentrations of pure CaCl2 or KCl solutions, with a preferential transport of Ca2+ in mixed KCl-CaCl2 solutions. Altogether, our findings demonstrate that the presence of calcium modulates the transport properties of the E channel by interacting preferentially with charged lipids through different mechanisms including direct Coulombic interactions and possibly inducing changes in membrane morphology.A new study shows that the pioneer transcription factor BLMP-1 governs the cyclic transcriptional output of hundreds of genes during Caenorhabditis elegans larval development. BLMP-1 is also critical for restarting the proper developmental dynamics of gene expression after nutritionally induced developmental arrest.Cells migrating through confined spaces are subject to mechanical stresses that can deform the nucleus and even rupture the nuclear envelope. A new study reveals that nuclear deformation is sufficient to trigger double-strand breaks at sites of active DNA replication.Knowing one's body dimensions is a core aspect of individual experience and self-awareness. A recent study illustrates how bees take into account their own body size both in preparation for and while traversing small gaps.A new study suggests that visual working memory usage is interestingly low during a more naturalistic virtual reality paradigm, compared to capacity estimates from traditional lab studies. This raises new questions about the use of working memory in everyday tasks.Animal phylogeny has always been controversial, but a new study brings some ****-needed order for two infamous wandering groups, the ctenophores and the Xenacoelomorphs. The study introduces an innovative approach to dissect systematic errors in the underlying methodology of molecular phylogenies.Animals use their sensory systems to detect danger in their environments. New research shows that larval zebrafish navigate away from dangerous salt water by using their olfactory systems to detect the presence of both sodium and chloride ions.Most binocular neurons in the mammalian visual cortex show matched selectivity for light stimuli presented through either eye. A recent study tracked the responses of individual neurons in early visual cortex over time, revealing that matched binocular selectivity develops through major rearrangements of binocular visual circuits.Timing the events in the evolution of eukaryotic cells is crucial to understanding this major transition. https://www.selleckchem.com/products/go-203.html A recent study reconstructs the origins of thousands of gene families ancestral to eukaryotes and, using a controversial approach, aims to order the events of eukaryogenesis.The basal ganglia regulate our behavior through the promotion and suppression of the actions that we perform. A new study has revealed a basal ganglia feedback circuit between the striatum and globus pallidus that can powerfully inhibit locomotion in ****.Once spectacular coral reefs have often become overrun by persistent seaweed. A new study reveals that elevating the density of herbivorous spider crabs to unnatural levels can reduce seaweed and help corals recover.Brain size scales with body weight, but a new study has discovered that key circuits in the visual cortex of one of the world's smallest primates, the mouse lemur, Microcebus murinus, are built at the same scale as their equivalents in larger-brained primates.Parachute science is the practice whereby international scientists, typically from higher-income countries, conduct field studies in another country, typically of lower income, and then complete the research in their home country without any further effective communication and engagement with others from that nation. It creates dependency on external expertise, does not address local research needs, and hinders local research efforts. As global hotspots of marine biodiversity, lower-income nations in the tropics have for too long been the subject of inequitable and unfair research practices1. However, to date there has been little quantifiable evidence of this phenomenon in marine science. Here, we provide evidence through systematic literature searches and queries that parachute science practices are still widespread in marine research and make some recommendations to help change the current status quo. VIDEO ABSTRACT.Hybrid sterility maintains reproductive isolation between species by preventing them from exchanging genetic material1. Anti-recombination can contribute to hybrid sterility when different species' chromosome sequences are too diverged to cross over efficiently during hybrid meiosis, resulting in chromosome mis-segregation and aneuploidy. The genome sequences of the yeasts Saccharomyces cerevisiae and Saccharomyces paradoxus have diverged by about 12% and their hybrids are sexually sterile nearly all of their gametes are aneuploid and inviable. Previous methods to increase hybrid yeast fertility have targeted the anti-recombination machinery by enhancing meiotic crossing over. However, these methods also have counteracting detrimental effects on gamete viability due to increased mutagenesis2 and ectopic recombination3. Therefore, the role of anti-recombination has not been fully revealed, and it is often dismissed as a minor player in speciation1. By repressing two genes, SGS1 and MSH2, specifically during meiosis whilst maintaining their mitotic expression, we were able to increase hybrid fertility 70-fold, to the level of non-hybrid crosses, confirming that anti-recombination is the principal cause of hybrid sterility.
The envelope protein E of the SARS-CoV coronavirus is an archetype of viroporin. It is a small hydrophobic protein displaying ion channel activity that has proven highly relevant in virus-host interaction and virulence. Ion transport through E channel was shown to alter Ca2+ homeostasis in the cell and trigger inflammation processes. Here, we study transport properties of the E viroporin in mixed solutions of potassium and calcium chloride that contain a fixed total concentration (mole fraction experiments). The channel is reconstituted in planar membranes of different lipid compositions, including a lipid mixture that mimics the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) membrane where the virus localizes within the cell. We find that the E ion conductance changes non-monotonically with the total ionic concentration displaying an Anomalous Mole Fraction Effect (AMFE) only when charged lipids are present in the membrane. We also observe that E channel insertion in ERGIC-mimic membranes - including lipid with intrinsic negative curvature - enhances ion permeation at physiological concentrations of pure CaCl2 or KCl solutions, with a preferential transport of Ca2+ in mixed KCl-CaCl2 solutions. Altogether, our findings demonstrate that the presence of calcium modulates the transport properties of the E channel by interacting preferentially with charged lipids through different mechanisms including direct Coulombic interactions and possibly inducing changes in membrane morphology.A new study shows that the pioneer transcription factor BLMP-1 governs the cyclic transcriptional output of hundreds of genes during Caenorhabditis elegans larval development. BLMP-1 is also critical for restarting the proper developmental dynamics of gene expression after nutritionally induced developmental arrest.Cells migrating through confined spaces are subject to mechanical stresses that can deform the nucleus and even rupture the nuclear envelope. A new study reveals that nuclear deformation is sufficient to trigger double-strand breaks at sites of active DNA replication.Knowing one's body dimensions is a core aspect of individual experience and self-awareness. A recent study illustrates how bees take into account their own body size both in preparation for and while traversing small gaps.A new study suggests that visual working memory usage is interestingly low during a more naturalistic virtual reality paradigm, compared to capacity estimates from traditional lab studies. This raises new questions about the use of working memory in everyday tasks.Animal phylogeny has always been controversial, but a new study brings some much-needed order for two infamous wandering groups, the ctenophores and the Xenacoelomorphs. The study introduces an innovative approach to dissect systematic errors in the underlying methodology of molecular phylogenies.Animals use their sensory systems to detect danger in their environments. New research shows that larval zebrafish navigate away from dangerous salt water by using their olfactory systems to detect the presence of both sodium and chloride ions.Most binocular neurons in the mammalian visual cortex show matched selectivity for light stimuli presented through either eye. A recent study tracked the responses of individual neurons in early visual cortex over time, revealing that matched binocular selectivity develops through major rearrangements of binocular visual circuits.Timing the events in the evolution of eukaryotic cells is crucial to understanding this major transition. https://www.selleckchem.com/products/go-203.html A recent study reconstructs the origins of thousands of gene families ancestral to eukaryotes and, using a controversial approach, aims to order the events of eukaryogenesis.The basal ganglia regulate our behavior through the promotion and suppression of the actions that we perform. A new study has revealed a basal ganglia feedback circuit between the striatum and globus pallidus that can powerfully inhibit locomotion in mice.Once spectacular coral reefs have often become overrun by persistent seaweed. A new study reveals that elevating the density of herbivorous spider crabs to unnatural levels can reduce seaweed and help corals recover.Brain size scales with body weight, but a new study has discovered that key circuits in the visual cortex of one of the world's smallest primates, the mouse lemur, Microcebus murinus, are built at the same scale as their equivalents in larger-brained primates.Parachute science is the practice whereby international scientists, typically from higher-income countries, conduct field studies in another country, typically of lower income, and then complete the research in their home country without any further effective communication and engagement with others from that nation. It creates dependency on external expertise, does not address local research needs, and hinders local research efforts. As global hotspots of marine biodiversity, lower-income nations in the tropics have for too long been the subject of inequitable and unfair research practices1. However, to date there has been little quantifiable evidence of this phenomenon in marine science. Here, we provide evidence through systematic literature searches and queries that parachute science practices are still widespread in marine research and make some recommendations to help change the current status quo. VIDEO ABSTRACT.Hybrid sterility maintains reproductive isolation between species by preventing them from exchanging genetic material1. Anti-recombination can contribute to hybrid sterility when different species' chromosome sequences are too diverged to cross over efficiently during hybrid meiosis, resulting in chromosome mis-segregation and aneuploidy. The genome sequences of the yeasts Saccharomyces cerevisiae and Saccharomyces paradoxus have diverged by about 12% and their hybrids are sexually sterile nearly all of their gametes are aneuploid and inviable. Previous methods to increase hybrid yeast fertility have targeted the anti-recombination machinery by enhancing meiotic crossing over. However, these methods also have counteracting detrimental effects on gamete viability due to increased mutagenesis2 and ectopic recombination3. Therefore, the role of anti-recombination has not been fully revealed, and it is often dismissed as a minor player in speciation1. By repressing two genes, SGS1 and MSH2, specifically during meiosis whilst maintaining their mitotic expression, we were able to increase hybrid fertility 70-fold, to the level of non-hybrid crosses, confirming that anti-recombination is the principal cause of hybrid sterility.
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