Microglia help limit the progression of Alzheimer's disease (AD) by constraining amyloid-β (Aβ) pathology, effected through a balance of activating and inhibitory intracellular signals delivered by distinct cell surface receptors. Human leukocyte Ig-like receptor B4 (LILRB4) is an inhibitory receptor of the immunoglobulin (Ig) superfamily that is expressed on myeloid cells and recognizes apolipoprotein E (ApoE) among other ligands. Here, we find that LILRB4 is highly expressed in the microglia of patients with AD.
View Article and Find Full Text PDFObjectives: Active RA has been associated with an increased risk of both cardiovascular and peripheral vascular disease. We aimed to compare cerebrovascular changes in patients with and without RA, both with and without a neuropathologic diagnosis of neurodegenerative disease.
Methods: Patients with RA (n = 32) who died and underwent autopsy between 1994 and 2021 were matched to non-RA controls (n = 32) on age, sex and level of neurodegenerative proteinopathy.
The literature regarding the neuropathological findings in cases of SARS-CoV-2 infection, which causes coronavirus disease 2019 (COVID-19), is expanding. We identified 72 patients who died of COVID-19 (n = 48) or had recovered shortly before death (n = 24) and had autopsies performed at our institution (49 males, 23 females; median age at death 76.4 years, range: 0.
View Article and Find Full Text PDFProkaryotes rely on a distant tubulin homolog, FtsZ, for assembling the cytokinetic ring essential for cell division, but are otherwise generally thought to lack tubulin-like polymers that participate in processes such as DNA segregation. Here we characterize a protein (TubZ) from the Bacillus thuringiensis virulence plasmid pBtoxis, which is a member of the tubulin/FtsZ GTPase superfamily but is only distantly related to both FtsZ and tubulin. TubZ assembles dynamic, linear polymers that exhibit directional polymerization with plus and minus ends, movement by treadmilling, and a critical concentration for assembly.
View Article and Find Full Text PDFWe here identify a protein (AlfA; actin like filament) that defines a new family of actins that are only distantly related to MreB and ParM. AlfA is required for segregation of Bacillus subtilis plasmid pBET131 (a mini pLS32-derivative) during growth and sporulation. A 3-kb DNA fragment encoding alfA and a downstream gene (alfB) is necessary and sufficient for plasmid stability.
View Article and Find Full Text PDFA highly efficient method of transposon mutagenesis was developed for genetic analysis of Xanthobacter autotrophicus Py2. The method makes use of a transposon delivery vector that encodes a hyperactive Tn 5 transposase that is 1,000-fold more active than the wild-type transposase. In this construct, the transposase is expressed from the promoter of the tetA gene of plasmid RP4, which is functional in a wide variety of organisms.
View Article and Find Full Text PDFAcetone carboxylase is the key enzyme of bacterial acetone metabolism, catalyzing the condensation of acetone and CO(2) to form acetoacetate. In this study, the acetone carboxylase of the purple nonsulfur photosynthetic bacterium Rhodobacter capsulatus was purified to homogeneity and compared to that of Xanthobacter autotrophicus strain Py2, the only other organism from which an acetone carboxylase has been purified. The biochemical properties of the enzymes were virtually indistinguishable, with identical subunit compositions (alpha(2)beta(2)gamma(2) multimers of 85-, 78-, and 20-kDa subunits), reaction stoichiometries (CH(3)COCH(3) + CO(2) + ATP-->CH(3)COCH(2)COO(-) + H(+) + AMP + 2P(i)), and kinetic properties (K(m) for acetone, 8 microM; k(cat) = 45 min(-1)).
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