Isozyme Patterns of Lactate Dehydrogenase from Tissues of Mink and Arctic Fox during Postnatal Development

Isozymes of lactate dehydrogenase extracted from heart, kidney, and liver of mink (Mustela vison Briss.) and Arctic fox (Alopex lagopus L.) during postnatal development were separated by agarose gel electrophoresis. Tissue-specific isozyme pattern of lactate dehydrogenase can be revealed at the age of one month, while the definitive pattern is formed at the age of four months. The isozyme patterns of lactate dehydrogenase in the studied tissues of mink and Arctic fox share the properties specific for animal species of various ecogenesis.     

The Unique FauI Restriction–Modification System: Cloning and Protein Sequence Comparisons

The nucleotide sequence was established for the full-length Flavobacterium aquatile operon coding for the FauI restriction–modification system. The operon is unusual in structure and has the gene order control protein / DNA methyltransferase A / restriction endonuclease / DNA methyltransferase B, other than in the known analogs; the genes are similarly oriented and overlap. On evidence of sequence analysis, both methyltransferases are C5 enzymes, the control protein is similar to that of other restriction–modification systems, and the restriction endonuclease shows low similarity to other enzymes cleaving the DNA upper strand in position 4 or 5 relative to the recognition site.     

Rhythm of Protein Synthesis in Cultures of Hepatocytes from Rats of Different Ages. Norm and Effect of the Peptide Lyvagen

The circumhoralian rhythm of protein synthesis was determined in a monolayer culture of hepatocytes from rats at the age of 1 to 24 months and weighing from 45 to 480 g, respectively. The peptide lyvagen (Lys-Glu-Asp-Ala) obtained by directed chemical synthesis on the basis of amino acid analysis of the liver polypeptide preparations increased the level of protein synthesis in the hepatocytes from rats of different ages; the highest effect was observed in the cells of old animals. In old rats, lyvagen increased the amplitude of protein synthesis fluctuations. The peptide epitalon (Ala-Glu-Asp-Gly) constructed on the basis of analysis of the epiphysis peptides did not change the intensity of protein synthesis in the cultured hepatocytes.     

The Role of Preventing Nitric Oxide Deficiency in the Antihypertensive Effect of Adaptation to Hypoxia

Shortage of endothelial nitric oxide (NO) manifested as decreased daily urinary excretion of nitrate and nitrite as well as attenuated endothelium-dependent relaxation of conduit and resistance vessels progresses with age-related increase of blood pressure (BP) in stroke-prone spontaneously hypertensive rats (SHRSP). Simultaneous NO-dependent suppression of vascular contractions is, apparently, due to the inducible NO synthase activity in vascular smooth muscle specific for spontaneously hypertensive rat. The adaptation of rats to hypobaric hypoxia initiated at early hypertensive stage (at the age of 5–6 weeks) decelerates hypertension progress. The antihypertensive effect of the adaptation was accompanied by stimulation of endothelial NO synthesis and prevention of impaired NO-dependent response in isolated blood vessels. Nitric oxide stores were formed in the vascular wall of SHRSP and WKY rats at the same time. The obtained data indicate that the correction of endothelial NO deficiency plays a significant role in the antihypertensive effect of adaptation to hypoxia.     

Ontogenesis of Oxidative Reaction of 17β-hydroxysteroid Dehydrogenase and 11β-hydroxysteroid Dehydrogenase in Rat Leydig Cells, a Histochemical Study

The enzyme 17β-hydroxysteroid dehydrogenase is required for the synthesis and 11β-hydroxysteroid dehydrogenase for the regulation of androgens in rat Leydig cells. This histochemical study describes ontogenetic changes in distribution and intensity of these enzymes in Leydig cells from postnatal day (pnd) 1–90. Using NAD or NADP as the cofactor, 17β-hydroxysteroid dehydrogenase (substrate: 5-androstene-3β, 17β-diol) peaks were observed on pnd 16 for fetal Leydig cells and on pnd 19 and 37 for adult Leydig cells. Between pnd 13 and 25 the fetal cells showed a higher intensity for the 17β-enzyme than the adult cells; more fetal Leydig cells were stained with NADP, whereas more adult cells were positive with NAD on pnd 13 and 16. A nearly identical distribution of 11β-hydroxysteroid dehydrogenase (substrate: corticosterone) was observed with NAD or NADP as the cofactor; the reaction was present from pnd 31 onwards, first in a few adult Leydig cells and later in almost all these cells homogeneously. The ontogenetic curves of the two enzymes show an inverse relationship. To conclude: (1) Generally, a stronger reaction for 17β-hydroxysteroid dehydrogenase is shown with NAD as cofactor than with NADP; using NADP, fetal Leydig cells show a stronger staining than adult Leydig cells. (2) The data possibly support the notion of a new isoform of 11β -hydroxysteroid dehydrogenase in addition to types 1 and 2.     

Mock microbial community meta-analysis using different trimming of amplicon read lengths

Trimming of sequencing reads is a pre-processing step that aims to discard sequence segments such as primers, adapters and low quality nucleotides that will interfere with clustering and classification steps. We evaluated the impact of trimming length of paired-end 16S and 18S rRNA amplicon reads on the ability to reconstruct the taxonomic composition and relative abundances of communities with a known composition in both even and uneven proportions. We found that maximizing read retention maximizes recall but reduces precision by increasing false positives. The presence of expected taxa was accurately predicted across broad trim length ranges but recovering original relative proportions remains a difficult challenge. We show that parameters that maximize taxonomic recovery do not simultaneously maximize relative abundance accuracy. Trim length represents one of several experimental parameters that have non-uniform impact across microbial clades, making it a difficult parameter to optimize. This study offers insights, guidelines, and helps researchers assess the significance of their decisions when trimming raw reads in a microbiome analysis based on overlapping or non-overlapping paired-end amplicons.     

Targeting the BspC-vimentin interaction to develop anti-virulence therapies during Group B streptococcal meningitis

Bacterial infections are a major cause of morbidity and mortality worldwide and the rise of antibiotic resistance necessitates development of alternative treatments. Pathogen adhesins that bind to host cells initiate disease pathogenesis and represent potential therapeutic targets. We have shown previously that the BspC adhesin in Group B Streptococcus (GBS), the leading cause of bacterial neonatal meningitis, interacts with host vimentin to promote attachment to brain endothelium and disease development. Here we determined that the BspC variable (V-) domain contains the vimentin binding site and promotes GBS adherence to brain endothelium. Site directed mutagenesis identified a binding pocket necessary for GBS host cell interaction and development of meningitis. Using a virtual structure-based drug screen we identified compounds that targeted the V-domain binding pocket, which blocked GBS adherence and entry into the brain in vivo. These data indicate the utility of targeting the pathogen-host interface to develop anti-virulence therapeutics.     

Increase in activity and biosynthesis of phospholipase A of Entamoeba histolytica by cholesterol passage

Phospholipase A (EC 3.1.1.4) activity was detected in trophozoites and cell-free culture medium of Entamoeba histolytica NIH-200. The enzyme from both the sources gave two pH optima at 4.2 and 9.0 and was stimulated by addition of CaCl₂. Cholesterol passage of the amoeba increased the enzyme activity and trophozoite-multiplication. The enzyme was purified by submitting the trophozoites to freezing and thawing, treatment with triton X-100, heat denaturation, and chromatography on Sephadex G-100. The purified enzyme resolved on sodium dodecyl sulphate gel electrophoresis into two protein bands, one exhibiting optimal phospholipase A activity at pH 4.2 and the other at pH 9.0. Incorporation of ¹⁴C ammo acids into the proteins at various stages of enzyme purification suggests that cholesterol passage increased the synthesis and activity of phospholipase A in the trophozoites.     

Transgenic Tobacco Plants Expressing Bacterial Genes for Thermostable Glucanases

It is shown that bacterial genes for thermostable -glucanases are expressed retaining their activity and substrate specificity. The leader peptide of the carrot extensin exerts effective secretion of the bacterial enzymes into the intercellular space of the plant tissue. Expression of the bacterial gene for -1,3-glucanase in plant tissues alters their morphogenetic potential. Regeneration of shoots from the calli of these plant lines requires a six- to eightfold increase in cytokinin (6-BAP) concentration in comparison with the control lines and the transgenic lines expressing -1,3-1,4-glucanase. Rooting of transgenic plants expressing the bacterial gene for -1,3-glucanase occurs much faster. The transgenic plants obtained in the study are proposed as model objects for investigating the role of glucanases in plants.