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Helpful or Harmful? The Role associated with Personality inside College student Experiences from the COVID-19 Situation and faculty End.
In this issue of Cell Host & Microbe, Jia et al. used a vesicular stomatitis virus-based probe to isolate B cells expressing broadly neutralizing HIV-1 antibodies. Besides identifying neutralizing epitopes, this study highlights potential protection afforded by IgA arising from either direct IgM-to-IgA or sequential IgM-to-IgG-to-IgA class switching.In this issue of Cell Host and Microbe, Lee et al. define the glycan binding specificity of a variant of typhoid toxin produced by a non-typhoidal Salmonellae serotype. The authors elegantly demonstrate that tissue and host specificity of the toxin are related to specific glycan binding characteristics of the toxin.Childhood undernutrition is associated with dysbiosis and dampened vaccine responses. Understanding how nutrients influence the microbiota and immunity is critical for vaccine efficacy. In this issue of Cell Host & Microbe, Di Luccia et al. and Huus et al. reveal that nutrition affects IgA responses to the microbiota and oral vaccines.Over 3000 membrane-active antimicrobial peptides (AMPs) have been discovered, but only three of them have been approved by the U.S. Food and Drug Administration (FDA) for therapeutic applications, i.e., gramicidin, daptomycin and colistin. Of the three approved AMPs, daptomycin is a last-line-of-defense antibiotic for treating Gram-positive infections. However its use has already created bacterial resistance. To search for its substitutes that might counter the resistance, we need to understand its molecular mechanism. The mode of action of daptomycin appears to be causing bacterial membrane depolarization through ion leakage. Daptomycin forms a unique complex with calcium ions and phosphatidylglycerol molecules in membrane at a specific stoichiometric ratio Dap2Ca3PG2. How does this complex promote ion conduction across the membrane? We hope that biophysics of peptide-membrane interaction can answer this question. This review summarizes the biophysical works that have been done on membrane-active AMPs to understand their mechanisms of action, including gramicidin, daptomycin, and underdeveloped pore-forming AMPs. The analysis suggests that daptomycin forms transient ionophores in the target membranes. We discuss questions that remain to be answered.Plants have evolved a sophisticated innate immune system to defend against pathogen infection, and intracellular nucleotide-binding, leucine-rich repeat (NLR or NB-LRR) immune receptors are one of the main components of this system. NLR activity is fine-tuned by intra- and intermolecular interactions. We survey what is known about the conservation and diversity of NLR-interacting proteins, and divide them into seven major categories. We discuss the molecular mechanisms by which NLR activities are regulated and how understanding this regulation has potential to facilitate the engineering of NLRs for crop improvement.Ubiquitously expressed in plants, the plant-specific insert (PSI) of typical plant aspartic proteases (tpAPs) has been associated with plant development, stress response, and defense processes against invading pathogens. Despite sharing high sequence identity, structural studies revealed possible different mechanisms of action among species. The PSI induces signaling pathways of defense hormones in vivo and demonstrates broad-spectrum activity against phytopathogens in vitro. Recent characterization of the PSI-tpAP relationship uncovered novel, nonconventional intracellular protein transport pathways and improved tpAP production yields for industrial applications. In spite of research to date, relatively little is known about the structure-function relationships of PSIs. A comprehensive understanding of their biological roles may benefit plant protection strategies against virulent phytopathogens.In plants, high carbon flux is committed to the biosynthesis of phenylalanine, tyrosine, and tryptophan, owing to their roles not only in the production of proteins, but also as precursors to thousands of primary and specialized metabolites. The core plastidial pathways that supply the majority of aromatic amino acids (AAAs) have previously been described in detail. More recently, the discovery of cytosolic enzymes contributing to overall AAA biosynthesis, as well as the identification of intracellular transporters and the continuing elucidation of transcriptional and post-transcriptional regulatory mechanisms, have revealed the complexity of this intercompartmental metabolic network. Here, we review the latest breakthroughs in AAA production and use the newest findings to highlight both longstanding and newly developed questions.Enzymes catalyze reactions in vivo at different rates and each enzyme molecule has a lifetime limit before it is degraded and replaced to enable catalysis to continue. Considering these rates together as a unitless ratio of catalytic cycles until replacement (CCR) provides a new quantitative tool to assess the replacement schedule of and energy investment into enzymes as they relate to function. see more Here, we outline the challenges of determining CCRs and new approaches to overcome them and then assess the CCRs of selected enzymes in bacteria and plants to reveal a range of seven orders of magnitude for this ratio. Modifying CCRs in plants holds promise to lower cellular costs, to tailor enzymes for particular environments, and to breed enzyme improvements for crop productivity.With increasing calls for improving terrestrial carbon sequestration and sustainable water use, scientists are faced with the challenge of predicting changes in carbon-water relations from organisms to landscapes. We propose an integrative framework to help in answering basic and applied questions pertaining to coupled carbon-water functions in a variety of ecosystems. The conceptual framework is based on data from a globally representative set of ecosystems that hold vast amounts of carbon and provide water for rural and urban land uses. We focus on examples that demonstrate the value of an integrated approach that combines fast- and slow-changing state factors (i.e., variables that define structural properties and functional processes at the soil-plant-atmosphere interface) to improve predictions of carbon-water relations across scales.
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