A mutation-level covariate model for mutational signatures.

Mutational processes and their exposures in particular genomes are key to our understanding of how these genomes are shaped. However, current analyses assume that these processes are uniformly active across the genome without accounting for potential covariates such as strand or genomic region that could impact such activities. Here we suggest the first mutation-covariate models that explicitly model the effect of different covariates on the exposures of mutational processes.

Dual energy metabolism-dependent effect of Ureaplasma urealyticum infection on sperm activity.

Genital Ureaplasma urealyticum infection is considered a sexually transmitted infection. It has long been debated whether the presence of U. urealyticum in semen may be a possible cause of infertility.

In vivo and in vitro impairment of human and ram sperm nuclear chromatin integrity by sexually transmitted Ureaplasma urealyticum infection.

The incidence of Ureaplasma urealyticum infection in the semen of infertile men is variable (7%-42%). Evidence has accumulated through routine semen analysis to suggest that this infection can cause embryo loss without necessarily affecting sperm quality. The aim of this study was to specifically investigate the effects of U.

Meloidogyne javanica surface proteins: characterization and lability.

Characterization of surface coat (SC) proteins including carbohydrate-binding proteins and glycoproteins of the plant-parasitic nematode Meloidogyne javanica 2nd-stage juvenile (J2) is reported. Extraction of surface proteins with sodium dodecyl sulfate (SDS) and separation by denaturing polyacrylamide gel electrophoresis (SDS-PAGE) results with bands at 6, 9, 14, 22, 26, 31, 46, 49, 58, 66, 80, 205 and 250 kDa. On Western blots, the neoglycoprotein, fucosylated-, mannosylated- and glucosylated-bovine serum albumin, reacted with the 14, 22, 26, 58 and 66 kDa bands.

Adherence of Mycoplasma gallisepticum involves variable surface membrane proteins.

Adherence of Mycoplasma gallisepticum to erythrocytes was examined by colony immunoblotting, detergent phase fractionation, trypsin treatment, comparison of protein profiles, and comparison of erythrocyte-bound mycoplasma protein fractions of hemadsorption-positive and -negative mutants. The binding of M. gallisepticum to chicken or human erythrocytes was found to be mediated via surface-exposed membrane proteins undergoing high-frequency phase variation.

Adherence of Mycoplasma pneumoniae to human alveolar macrophages.

The human pathogen Mycoplasma pneumoniac causes primary atypical-cold agglutinin-positive pneumonia. Since alveolar macrophages internalize mycoplasma as part of their immune defense, we studied characteristics of the human macrophage receptor for opsonized and nonopsonized M. pneumoniae.

Mycoplasmas regulate HIV-LTR-dependent gene expression.

Mycoplasmas have been incriminated in setting the stage for HIV infection and full-blown AIDS. We tested the possible involvement of mycoplasmas in activation of HIV. Two cell lines, 293 fibroblasts and Jurkat CD4+ T-cells, transfected with plasmids harboring a transcription fusion construct between HIV-long terminal repeat (HIV-LTR) and either luc or cat genes, were infected with several mycoplasmas (M.

Carbohydrate-recognition domains on the surface of phytophagous nematodes.

Human red blood cells (HRBC) adhered to preparasitic second-stage juveniles (J2) of Heterodera avenae, Heterodera schachtii, Meloidogyne javanica, Pratylenchus mediterraneus, Rotylenchulus reniformis, and Tylenchulus semipenetrans over the entire nematode body. Binding was conspicuously confined to the head and tail of Longidorus cohni, Xiphinema brevicolle, and Xiphinema index. Binding was Ca2+ and Mg2+ dependent.

Cyclodextrins as carriers of cholesterol and fatty acids in cultivation of mycoplasmas.

The design of fully or partly defined media for mycoplasma cultivation involves the need to provide the essential lipids, cholesterol and long-chain fatty acids, in an assimilable and nontoxic form. This study introduces cyclodextrins (CDs) as carriers of these lipids, thus suggesting alternatives to serum or bovine serum albumin (BSA). The effects of beta-CD and two forms of chemically modified beta-CD, dimethyl-beta-CD (Dimeb) and hydroxypropyl-beta-CD (Hyprob), on the growth of Mycoplasma capricolum and Acholeplasma laidlawii were investigated in a basal medium as well as in serum- and BSA-supplemented media.

Wheat Germ Agglutinin Bound to the Outer Cuticle of the Seed Gall Nematodes Anguina agrostis and A. tritici.

The presence of wheat germ agglutinin (WGA) on the cuticular surface of the seed gall nematodes Anguina agrostis and Anguina tritici was demonstrated, and the nature of its binding was examined. Crude extracts from the cuticles of A. tritici agglutinated human red blood cells, and only N-acetylglucosamine (GlucNAc) inhibited the agglutination.

Adherence of Ureaplasma urealyticum to human erythrocytes.

Ureaplasma urealyticum (four serotypes and two clinical isolates) were metabolically labeled with radioactive methionine to a high specific activity. Labeling allowed the study of the mechanism of adherence to human erythrocytes. The adherence mechanism was complex and partially mediated by proteinaceous surface components.

Panagrellus redivivus and Caenorhabditis elegans: evidence for the absence of sialic acids.

Complementary experiments were performed to indicate the presence or absence of sialic acids in axenically cultured Panagrellus redivivus and Caenorhabditis elegans. Competitive displacement experiments with radiolabeled Limax flavus agglutinin demonstrated the presence of sialic acid in nematodes grown in medium which contained liver extract as a growth factor but the absence of sialic acid when heme was substituted for liver extract. This finding suggested that sialic acid present in the liver medium was responsible for conflicting results of other studies.

Glycosidase activities of mycoplasmas.

The activities of alpha- and beta-glucosidase, beta-galactosidase and beta-N acetylglucosaminidase were assessed at acidic pH by fluorimetry using the appropriate 4-methylumbelliferyl substrate in four Mycoplasma species (M. pneumoniae, M. gallisepticum, M.

Characterization of monoclonal antibodies to human platelet myosin that recognize highly conserved epitopes within the 50 kDa fragment of myosin subfragment-1.

Three monoclonal antibodies directed against human platelet myosin heavy chains (MCH) that recognize homologous sequences contained within the functionally active subfragment-1, in platelet and rabbit skeletal muscle myosin were studied. These antibodies are distinguished by their affinities to different myosins and their differential effect on various ATPase activities. Epitope mapping was accomplished by analyzing antibody binding to proteolytic peptides of myosin head subfragment-1 under various experimental conditions.

Structural and immunological properties of myosin from human platelet external and internal membranes.

Our previous studies indicate that platelets contain two myosin isoforms, one of them localized in the membrane while the other in the cytoplasmic compartment. Structural and functional differences of these myosins have been characterized. In this study two platelet membrane subfractions, the external and the internal membranes, were isolated simultaneously from a crude membrane fraction and their purity was characterized using specific marker enzymes.

Iron loading modifies the fatty acid composition of cultured rat myocardial cells and liposomal vesicles: effect of ascorbate and alpha-tocopherol on myocardial lipid peroxidation.

Increased generation of free radicals and accelerated lipid peroxidation are important manifestations of iron toxicity. We have studied the effect of iron loading on lipid peroxidation in cultured rat myocardial cells by direct measurement of the fatty acid composition of cellular lipids. Iron loading produced by 24-hour incubation of cultured cells with 0.

Altered structural and functional properties of myosins, from platelets of idiopathic scoliosis patients.

Platelets of patients with idiopathic scoliosis (IS) have been shown to have decreased capacity to aggregate and secrete in response to certain agonists. Similarities between the contractile protein system of platelets and muscle have made the platelets a popular model for muscle disease. We attempted to characterize the function and structure of myosin in platelets of IS patients.

Purification and characterization of urease from Ureaplasma urealyticum.

The urease from Ureaplasma urealyticum strain T 960 was isolated by the use of affinity chromatography, hydrophobic chromatography and gel filtration. The enzyme was purified by a factor of 155. The urease appeared as a single band of molecular weight (MW) 75,000 using reducing conditions in SDS-polyacrylamide gel electrophoresis.

Preliminary X-ray diffraction results on co-crystals of wheat germ agglutinin with a sialoglycopeptide from the red cell receptor glycophorin A.

Diffraction-quality crystals have been obtained for complexes of each of the major wheat germ agglutinin (WGA) isolectins with the tryptic sialoglycopeptide T-5 from the WGA red cell receptor glycophorin A. This octa-glycopeptide possesses a Thr-linked carbohydrate moiety (GalNAc(NeuNAc)-Gal-NeuNAc) with specificity for the WGA binding site. The crystals belong to the orthorhombic space group P2(1)2(1)2 and have unit cell dimensions: a = 112.