scholarly journals Schizorhodopsins: A family of rhodopsins from Asgard archaea that function as light-driven inward H+ pumps

2020 ◽  
Vol 6 (15) ◽  
pp. eaaz2441 ◽  
Author(s):  
Keiichi Inoue ◽  
Satoshi P. Tsunoda ◽  
Manish Singh ◽  
Sahoko Tomida ◽  
Shoko Hososhima ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Life Cycle ◽  
Patch Clamp ◽  
Ion Transport ◽  
Mammalian Cells ◽  
Transport Mechanism ◽  
Biological Function ◽  
Molecular Properties ◽  
Trimeric Structure ◽  
Insight Into

Schizorhodopsins (SzRs), a rhodopsin family first identified in Asgard archaea, the archaeal group closest to eukaryotes, are present at a phylogenetically intermediate position between typical microbial rhodopsins and heliorhodopsins. However, the biological function and molecular properties of SzRs have not been reported. Here, SzRs from Asgardarchaeota and from a yet unknown microorganism are expressed in Escherichia coli and mammalian cells, and ion transport assays and patch clamp analyses are used to demonstrate SzR as a novel type of light-driven inward H+ pump. The mutation of a cytoplasmic glutamate inhibited inward H+ transport, suggesting that it functions as a cytoplasmic H+ acceptor. The function, trimeric structure, and H+ transport mechanism of SzR are similar to that of xenorhodopsin (XeR), a light-driven inward H+ pumping microbial rhodopsins, implying that they evolved convergently. The inward H+ pump function of SzR provides new insight into the photobiological life cycle of the Asgardarchaeota.

Host factors involved in influenza virus infection

2020 ◽  
Vol 4 (4) ◽  
pp. 401-410
Author(s):  
Matloob Husain
Keyword(s):  
Influenza Virus ◽  
Plasma Membrane ◽  
Life Cycle ◽  
Virus Infection ◽  
Mammalian Cells ◽  
Influenza Virus Infection ◽  
Host Factors ◽  
Tremendous Amount ◽  
Human Viruses ◽  
Insight Into

Influenza virus causes an acute febrile respiratory disease in humans that is commonly known as ‘flu’. Influenza virus has been around for centuries and is one of the most successful, and consequently most studied human viruses. This has generated tremendous amount of data and information, thus it is pertinent to summarise these for, particularly interdisciplinary readers. Viruses are acellular organisms and exist at the interface of living and non-living. Due to this unique characteristic, viruses require another organism, i.e. host to survive. Viruses multiply inside the host cell and are obligate intracellular pathogens, because their relationship with the host is almost always harmful to host. In mammalian cells, the life cycle of a virus, including influenza is divided into five main steps: attachment, entry, synthesis, assembly and release. To complete these steps, some viruses, e.g. influenza utilise all three parts — plasma membrane, cytoplasm and nucleus, of the cell; whereas others, e.g. SARS-CoV-2 utilise only plasma membrane and cytoplasm. Hence, viruses interact with numerous host factors to complete their life cycle, and these interactions are either exploitative or antagonistic in nature. The host factors involved in the life cycle of a virus could be divided in two broad categories — proviral and antiviral. This perspective has endeavoured to assimilate the information about the host factors which promote and suppress influenza virus infection. Furthermore, an insight into host factors that play a dual role during infection or contribute to influenza virus-host adaptation and disease severity has also been provided.

scholarly journals Quantification of the ion transport mechanism in protective polymer coatings on lithium metal anodes

2021 ◽  
Author(s):  
Hongyao Zhou ◽  
Haodong Liu ◽  
Xing Xing ◽  
Zijun Wang ◽  
Sicen Yu ◽  
...  
Keyword(s):  
Ion Transport ◽  
Transport Mechanism ◽  
Polymer Coatings ◽  
Rechargeable Batteries ◽  
Cycle Life ◽  
Lithium Metal ◽  
Lithium Metal Anodes ◽  
Protective Polymer ◽  
Deposition Morphology ◽  
Metal Anodes

Protective Polymer Coatings (PPCs) protect lithium metal anodes in rechargeable batteries to stabilize the Li/electrolyte interface and to extend the cycle life by reducing parasitic reactions and improving the lithium deposition morphology.

scholarly journals Racemization-free synthesis of Nα-2-thiophenoyl-phenylalanine-2-morpholinoanilide enantiomers and their antimycobacterial activity

Amino Acids ◽  
2021 ◽  
Author(s):  
Lea Mann ◽  
Markus Lang ◽  
Philipp Schulze ◽  
Jan Henrik Halz ◽  
René Csuk ◽  
...  
Keyword(s):  
Title Compound ◽  
Mammalian Cells ◽  
Antimycobacterial Activity ◽  
Lead Compound ◽  
Coupling Reagents ◽  
Hydrogen Bonding Interactions ◽  
Amide Coupling ◽  
Subsequent Separation ◽  
Synthetic Routes ◽  
Insight Into

AbstractNα-2-thiophenoyl-d-phenylalanine-2-morpholinoanilide (MMV688845, IUPAC: N-(1-((2-morpholinophenyl)amino)-1-oxo-3-phenylpropan-2-yl)thiophene-2-carboxamide) from the Pathogen Box® library (Medicines for Malaria Ventures, MMV) is a promising lead compound for antimycobacterial drug development. Two straightforward synthetic routes to the title compound starting from phenylalanine or its Boc-protected derivative are reported. Employing Boc-phenylalanine as starting material and the T3P® and PyBOP® amide coupling reagents enables racemization-free synthesis, avoiding the need for subsequent separation of the enantiomers. The crystal structure of the racemic counterpart gives insight into the molecular structure and hydrogen bonding interactions in the solid state. The R-enantiomer of the title compound (derived from d-phenylalanine) exhibits activity against non-pathogenic and pathogenic mycobacterial strains, whereas the S-enantiomer is inactive. Neither of the enantiomers and the racemate of the title compound shows cytotoxicity against various mammalian cells.

scholarly journals Infection by verocytotoxin-producing Escherichia coli.

1989 ◽  
Vol 2 (1) ◽  
pp. 15-38 ◽  
Author(s):  
M A Karmali
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Mammalian Cells ◽  
Significant Risk ◽  
Public Health Problem ◽  
Hemorrhagic Colitis ◽  
Commercial Development ◽  
High Biological Activity ◽  
Systemic Complications ◽  
Uremic Syndrome

Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate that most patients with VTEC infection develop mild uncomplicated diarrhea. However, a significant risk of two serious and potentially life-threatening complications, hemorrhagic colitis and the hemolytic uremic syndrome, makes VTEC infection a public health problem of serious concern. The main reservoirs of VTEC appear to be the intestinal tracts of animals, and foods of animal (especially bovine) origin are probably the principal sources for human infection. The term VT refers to a family of subunit exotoxins with high biological activity. Individual VTEC strains elaborate one or both of at least two serologically distinct, bacteriophage-mediated VTs (VT1 and VT2) which are closely related to Shiga toxin and are thus also referred to as Shiga-like toxins. The holotoxins bind to cells, via their B subunits, to a specific receptor which is probably the glycolipid, globotriosyl ceramide (Gb3). Binding is followed by internalization of the A subunit, which, after it is proteolytically nicked and reduced to the A1 fragment, inhibits protein synthesis in mammalian cells by inactivating 60S ribosomal subunits through selective structural modification of 28S ribosomal ribonucleic acid. The mechanism of VTEC diarrhea is still controversial, and the relative roles of locally acting VT and "attaching and effacing adherence" of VTEC to the mucosa have yet to be resolved. There is increasing evidence that hemolytic uremic syndrome and possibly hemorrhagic colitis result from the systemic action of VT on vascular endothelial cells. The role of antitoxic immunity in preventing the systemic complications of VTEC infection is being explored. Antibiotics appear to be contraindicated in the treatment of VTEC infection. The most common VTEC serotype associated with human disease is O157:H7, but over 50 different VT-positive O:H serotypes have now been identified. The best strategies for diagnosing human VTEC infection include testing for the presence of free VT in fecal filtrates and examining fecal cultures for VTEC by means of deoxyribonucleic acid probes that specify genes encoding VT1 and VT2. Both methods are currently confined to specialized laboratories and await commercial development for wider use. In the meantime, most laboratories should continue to screen for the most common human VTEC serotype, O157:H7, using a sorbitol-containing MacConkey medium.

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