| viXra.org > Biochemistry > 2406 |
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| viXra.org > Biochemistry > 2406 |
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[3] viXra:2406.0087 [pdf] submitted on 2024-06-18 19:44:32
Authors: Irshad Ahmad, Muhammad Ali, Roshan Ali, Nighat Nawaz, Simon G. Patching
Comments: 32 Pages.
Multidrug efflux proteins, also known as efflux pumps, are one of the major mechanisms that bacteria have evolved for their resistance against antimicrobial agents. Gram-negative bacteria are intrinsically more resistant to many antibiotics and biocides due to their cell structure and the activity of multidrug efflux proteins. These transporters actively extrude antibiotics and other xenobiotics from the cytoplasm or surrounding membranes of cells to the external environment. Based on amino acid sequence similarity, substrate specificity and the energy source used to export their substrates, there are seven major families of distinct bacterial multidrug efflux proteins: ABC, RND, MFS, SMR, MATE, PACE, AbgT. Individual proteins may be highly specialized for one compound or highly promiscuous, transporting a broad range of structurally dissimilar substrates. Protein structural organization in a large majority of the families, including the number of transmembrane helices, has been confirmed by high-resolution structure determination for at least one member. In this book chapter, we provide an updated review on the families of bacterial multidrug efflux proteins, including basic properties, energization, structural organization and molecular mechanism. Using representative proteins from each family, we also performed analyses of transmembrane helices, amino acid composition and distribution of charged residues. Ongoing characterization of structure-function relationships and regulation of bacterial multidrug efflux proteins are necessary for contributing new knowledge to assist drug development and strategies that will overcome antimicrobial resistance.
Category: Biochemistry
[2] viXra:2406.0029 [pdf] submitted on 2024-06-08 00:32:44
Authors: Yuan Xu, Kai-Ting Fan
Comments: 21 Pages.
Plant-microbe interactions lie at the heart of ecosystem dynamics and agricultural productivity. Metabolomics has revolutionized our understanding of these interactions, providing an unprecedented glimpse into the intricate chemical dialogues that shape their outcomes. This review explores the kaleidoscopic array of metabolomics techniques employed to investigate plant-microbe interactions, from the cutting-edge realms of mass spectrometry and nuclear magnetic resonance spectroscopy to the visually stunning world of imaging. We also delve into the application of state-of-the-art bioinformatics tools, databases, and the rapidly evolving fields of artificial intelligence and machine learning in metabolomics data analysis. By seamlessly weaving together metabolomics with other omics approaches, such as transcriptomics, proteomics, and metagenomics, we can paint a comprehensive portrait of the molecular tapestry that underlies plant-microbe interactions. Moreover, we shine a spotlight on the crucial complementary role of fluxomics in illuminating the dynamic ebb and flow of metabolic networks. Despite the formidable challenges inherent in data analysis, integration, and interpretation, metabolomics has catalyzed a paradigm shift in our understanding of the multifaceted roles metabolites play in sculpting plant-microbe interactions. As metabolomics technologies continue to evolve and synergize with other omics approaches, we find ourselves on the precipice of groundbreaking discoveries that will unravel these complex interactions and ultimately usher in a new era of sustainable agriculture and biotechnology.
Category: Biochemistry
[1] viXra:2406.0021 [pdf] submitted on 2024-06-06 20:30:06
Authors: Raul A. Félix de Sousa
Comments: 39 Pages.
A model for biopoesis is proposed where a complex, dynamic ecosphere, characterised by steep redox potentials, precedes and conditions the gradual formation of organismal life. A flow of electrons across the Archean hydrosphere, proceeding from the reducing constituents of the lithosphere and pumped by the photolytic production of oxygen in the Earth's atmosphere is the central feature of this protobiological environment. The available range of electrochemical potentials allows for the geochemical cycling of biogenic elements. In the case of carbon, carboxylation and decarboxylation reactions are essential steps, as in today's organisms. Geochemical evidence for high levels of carbon dioxide in the Earth's early atmosphere and the biological relevance of carboxylations are the basis for a hypercarbonic conception of the primitive metabolic pathways. Conversion of prochiral chemical species into chiral molecules, inherent to hypercarbonic transformations, suggests a mechanistic method for the generation of homochirality through propagation. The solubility of oxygen in lipid materials points to an aerobic course for the evolution of cellularity.
Category: Biochemistry
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