Characteristics of immunomodulating effect of histamine in inbred strain mice]

The activity of 5'-nucleotidase of peritoneal exudate in subcutaneous injection of histamine in a dose of 1.0-100 microliters was studied in mice of different lines (CBA, C57, B1/6, Balb/c, NFS/n, NFR/n). There were interline differences in the influence of histamine on this metabolic index.     

Characterization of the Structure and Biological Functions of a Capsular Polysaccharide Produced by Staphylococcus saprophyticus

Staphylococcus saprophyticus is a common cause of uncomplicated urinary tract infections in women. S. saprophyticus strain ATCC 15305 carries two staphylococcal cassette chromosome genetic elements, SCC_15305RM and SCC_15305cap. The SCC_15305cap element carries 13 open reading frames (ORFs) involved in capsular polysaccharide (CP) biosynthesis, and its G+C content (26.7%) is lower than the average G+C content (33.2%) for the whole genome. S. saprophyticus strain ATCC 15305 capD, capL, and capK (capD_Ssp, capL_Ssp, and capK_Ssp) are homologous to genes encoding UDP-FucNAc biosynthesis, and gtaB and capI_Ssp show homology to genes involved in UDP-glucuronic acid synthesis. S. saprophyticus ATCC 15305 CP, visualized by immunoelectron microscopy, was extracted and purified using anionic-exchange and size exclusion chromatography. Analysis of the purified CP by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy and gas-liquid chromatography revealed two types of branched tetrasaccharide repeating units composed of the following: Sug represents two stereoisomers of 2-acetamido-2,6-dideoxy-hexos-4-ulose residues, one of which has an arabino configuration. The encapsulated ATCC 15305 strain was resistant to complement-mediated opsonophagocytic killing by human neutrophils, whereas the acapsular mutant C1 was susceptible. None of 14 clinical isolates reacted with antibodies to the ATCC 15305 CP. However, 11 of the 14 S. saprophyticus isolates were phenotypically encapsulated based on their resistance to complement-mediated opsonophagocytic killing and their failure to hemagglutinate when cultivated aerobically. Ten of the 14 clinical strains carried homologues of the conserved staphylococcal capD gene or the S. saprophyticus gtaB gene, or both. Our results suggest that some strains of S. saprophyticus are encapsulated and that more than one capsular serotype exists.Approximately 13 million women develop urinary tract infections (UTIs) annually in the United States, with a recurrence rate between 25% and 44% (45). Staphylococcus saprophyticus is second only to Escherichia coli as a cause of uncomplicated UTI in young women (45, 46). A novobiocin-resistant member of the coagulase-negative staphylococci (60), S. saprophyticus has rarely exhibited resistance to other antibiotics (25). However, a recent report (19) indicated that methicillin-resistant S. saprophyticus isolates have emerged in Japan. The gastrointestinal tract and the vagina are the major reservoirs of S. saprophyticus (18, 30) and the likely sources of recurrent infection (20, 37, 49). Approximately 40% of patients with S. saprophyticus UTI present with acute pyelonephritis (22, 30). These patients experience symptoms more severe than those of patients infected by E. coli (24), and they are more likely to develop recurrent infections (21).A number of potential virulence factors have been identified in S. saprophyticus. Gatermann et al. showed that in a rodent model of ascending UTI, the production of urease contributes to S. saprophyticus growth and pathogenicity in the bladder (10, 12). Other putative virulence factors of S. saprophyticus include a surface-associated lipase (11, 51, 53), the collagen binding protein SdrI (52), and a cell wall-anchored hemagglutinin protein that mediates the binding of S. saprophyticus to sheep erythrocytes, fibronectin, and human uroepithelial cells (14, 29, 34, 35). The hemagglutinin was dubbed UafA in the sequenced ATCC 15305 strain, and deletion of the uafA gene resulted in reduced S. saprophyticus hemagglutination (HA) and adherence to human bladder carcinoma cells (29). Kuroda et al. noted that UafA-mediated adherence of S. saprophyticus to the T24 cell line was inhibited by the presence of the ATCC 15305 polysaccharide capsule (29).Staphylococcal species produce a variety of extracellular glycopolymers that contribute to the surface properties and virulence of the bacterium, such as capsular polysaccharides (CP), teichoic acids, and poly-N-acetylglucosamine (PNAG). CP production renders Staphylococcus aureus resistant to opsonophagocytic killing; alanine modifications of teichoic acids promote bacterial resistance to antimicrobial peptides (40); and PNAG is involved in biofilm formation (4). Recently, the secretion of another anionic polymer (poly-γ-dl-glutamic acid) by certain other coagulase-negative staphylococci was reported (28). Polyglutamic acid production is enhanced under high-salt conditions and may contribute to the survival of Staphylococcus epidermidis on human skin.S. saprophyticus strain 15305 does not produce PNAG or polyglutamic acid (28, 29), but this uropathogenic species is encapsulated. CP are lacking in isolates of S. epidermidis, the most common of the coagulase-negative species, but genomic evidence indicates that Staphylococcus haemolyticus (7, 57), S. saprophyticus (29), and Staphylococcus carnosus (47) carry capsule loci with genetic similarity to the Staphylococcus aureus cap5 (cap8) gene locus. In this study, we purified and characterized the CP produced by S. saprophyticus ATCC 15305 and investigated the CP phenotype of S. saprophyticus clinical isolates.     

Long-term results of chronic occlusion recanalization in patients with coronary heart disease

The study was undertaken to assess the long-term results of recanalization of chronically occluded coronary arteries, by applying drug-eluting stents to patients with coronary heart disease. The study enrolled 585 patients with one-vessel occlusive lesion of one of three great coronary arteries (TIMI 0; occlusion duration, > or = 3 months): 321 patients who underwent successful recanalization of chronic occlusion and further implantation of drug-eluting stents and 264 patients who received drug therapy (a control group). The short- and long-term results of recanalization were investigated. The follow-up averaged 1095 +/- 36 days; reexaminations were made after 1, 2, and 3 years. The direct success rate of recanalization of chronically occluded coronary arteries was 84.9% (321/378). The results of a 3-year follow-up showed the efficiency and expediency of endovascular recanalization of chronic occlusions: the invasively treated patients had the symptoms of angina pectoris and heart failure significantly less frequently, showed higher exercise tolerance and a less need for antianginal therapy, and had a better long-term prognosis.     

Zebra: a web server for bioinformatic analysis of diverse protein families

During evolution of proteins from a common ancestor, one functional property can be preserved while others can vary leading to functional diversity. A systematic study of the corresponding adaptive mutations provides a key to one of the most challenging problems of modern structural biology – understanding the impact of amino acid substitutions on protein function. The subfamily-specific positions (SSPs) are conserved within functional subfamilies but are different between them and, therefore, seem to be responsible for functional diversity in protein superfamilies. Consequently, a corresponding method to perform the bioinformatic analysis of sequence and structural data has to be implemented in the common laboratory practice to study the structure–function relationship in proteins and develop novel protein engineering strategies. This paper describes Zebra web server – a powerful remote platform that implements a novel bioinformatic analysis algorithm to study diverse protein families. It is the first application that provides specificity determinants at different levels of functional classification, therefore addressing complex functional diversity of large superfamilies. Statistical analysis is implemented to automatically select a set of highly significant SSPs to be used as hotspots for directed evolution or rational design experiments and analyzed studying the structure–function relationship. Zebra results are provided in two ways – (1) as a single all-in-one parsable text file and (2) as PyMol sessions with structural representation of SSPs. Zebra web server is available at http://biokinet.belozersky.msu.ru/zebra.     

Prebiotic Syntheses Under Shock in the Water – Formamide – Potassium Bicarbonate – Sodium Hydroxide System

Origins of Life and Evolution of Biospheres - Syntheses under shock in nitrogen bubbled samples of the water – formamide – bicarbonate – sodium hydroxide system at...