A chemically-defined medium for production of compactin by Penicillium citrinum

A mutant strain of Penicillium citrinum grown in a chemically-defined production medium, yielded 145 mg compactin l^–1. The medium also facilitated spectrophotometric analysis of compactin. Addition of KH₂PO₄in the production medium did not increase the compactin production, while addition of a surfactant, Tween 80, increased compactin to 175 mg l^–1. Inoculation with 10⁷ spores ml^–1 and initial pH of 6.5–7 were the most suitable for compactin production.     

Role of Ca2+ in induction and secretion of dengue virus-induced cytokines

The present study was undertaken to investigate the role of calcium ions (Ca₂₊) in the induction and secretion of the dengue type 2 virus induced cytotoxic factor and the cytotoxin. This was done by using calcium channel blocking drugs such as verapamil, nifedipine or diltiazem hydrochloride. The production of cytotoxic factor was significantly reduced by treatment of dengue type 2 virus infected mice with verapamil. Similarly, a dosedependent inhibition of the secretion of cytotoxic factor was observed, when spleen cells of the virus-primed mice were treatedin vitro with the 3 calcium channel blockers. The production of cytotoxin by macrophages was abrogated by pretreatment with calcium channel blockers but had little effect on its secretion as shown by treatment of macrophages with verapamil at 1 h after the induction to later periods up to 18 h. The findings thus show that in the induction of both the cytokines Ca₂₊ plays a critical role; on the other hand it is required for the secretion of the cytotoxic factor but not for that of the cytotoxin.     

Antibacterial Compound Isolation and Characterization from the Plant Cynotis axillaris Schult

A novel flavone glycoside was isolated from the methanolic extract of Cynotis axillaris Schult. Various analysis and characterization techniques were used to determine its structure and properties. The compound exhibited a melting point range of 231–232 °C and had a molecular formula of C₂₇H₃₀O₁₄. Several spectral characterization techniques were employed to establish the isolated compound's structure. These included UV-visible spectroscopy, FT-IR, LC-ESI-MS, and NMR spectroscopy. Based on these analyses, the structure of the isolated compound was determined to be 5,7,4’-trihydroxyflavone-8-α-L-rhamnopyranoside-4’-O-β-D-galactopyranosyl. This structure indicates that it is a flavone glycoside consisting of a flavone (5,7,4’-trihydroxyflavone) moiety attached to a sugar molecule (galactopyranosyl) at position 4’, which further bears a rhamnose group at position 8 of the flavone. In addition, to the structural characterization, the compound also demonstrated significant antibacterial efficacy against various bacterial pathogens, including Gram-positive bacteria such as Bacillus subtilis MTCC441 and Gram-negative bacteria such as Escherichia coli MTCC1098, Proteus vulgarize MTCC426, and Salmonella Typhimurium MTCC3224. The antimicrobial activity was evaluated by measuring the zone of inhibition in millimetres, which provides an indication of the compound's ability to inhibit bacterial growth. The study successfully identified and characterized a novel flavone glycoside from Cynotis axillaris Schult. and its antimicrobial activity.     

Isolation and hydroxylysine glycoside content of some cyanogen bromide-cleaved fragments of collagen from bovine corneal stroma.

1. Guinea-pig low-density lipoproteins were isolated by ultracentrifugation and iodinated either by the IC1 method or by the chloramine-T procedure. 2. The efficiency of labelling by both methods was essentially the same. 3. When the two products were compared by ultracentrifugation, gel chromatography and immunodiffusion analysis, no significant difference in their properties was detected. 4. When they were compared by gradient-gel electrophoresis, aggregates were found in the product of the IC1 method, but not in the lipoprotein iodinated by the chloramine-T process. 5. Both products were metabolized by the guinea pig with essentially the same fractional catabolic rate. 6. The fractional catabolic rate of lipoprotein iodinated by the chloramine-T method was not significantly different from that of lipoprotein biologically labelled in the protein moiety with [75Se]selenomethionine. 7. It is concluded that the products of both methods of iodination are almost equally acceptable, provided that the optimum conditions for the chloramine-T reaction are carefully established.     

Geometry of normal mammalian platelets by quantitative microscopic studies.

The shape distributions of normal and hardened human and rabbit erythrocytes and platelets were obtained for edge-on orientations of a few hundred freely rotating cells from analyses of microphotographs obtained similarly as by Ponder(1930, Q. J. Exp. Physiol. 20:29) by phase-contrast microscopy at 800 X magnification. Major average diameters (d) and thicknesses (t) were estimated for both normal and hardened cells, and were used to calculate an average geometric axis ratio, rp = t/d, which increases to unity as cells become more spherical. Our fixation procedure did not alter these shape parameters: rp was unchanged for erythrocytes, with d and t values similar to those reported by Ponder (1930); platelets had d X t = 3.6 +/- 0.7 mum X 0.9 +/- 0.3 mum and 3.1 +/- 0.4 mum X 0.6 +/- 0.3 mum, respectively, for human and rabbit cells, with rp = 0.26 and 0.20, respectively. Agreement in rp was found with data obtained by a novel rheo-optical method which allows for a direct statistical averaging for large populations (greater than 100 X 10(3) cells). Histograms and linear correlation studies were made of the above three parameters (d,t,rp), as well as volume (V), total surface area are (S), and sphericity index (S.I.) calculated for both "prolate ellipsoid" and "disc with rounded edges" models. Results indicate very high linear correlations between rp - t, rp - S. I., and d -S, with high correlations for t - V,d -V and S. Data are in agreement with the few reports in the literature determined by other methods, with the best model for platelets appearing to be an oblate spheroid.     

Nitric oxide blocks cellular heme insertion into a broad range of heme proteins

Although the insertion of heme into proteins enables their function in bioenergetics, metabolism, and signaling, the mechanisms and regulation of this process are not fully understood. We developed a means to study cellular heme insertion into apo-protein targets over a 3-h period and then investigated how nitric oxide (NO) released from a chemical donor (NOC-18) might influence heme (protoporphyrin IX) insertion into seven targets that present a range of protein structures, heme ligation states, and functions (three NO synthases, two cytochrome P450's, catalase, and hemoglobin). NO blocked cellular heme insertion into all seven apo-protein targets. The inhibition occurred at relatively low (nM/min) fluxes of NO, was reversible, and did not involve changes in intracellular heme levels, activation of guanylate cyclase, or inhibition of mitochondrial ATP production. These aspects and the range of protein targets suggest that NO can act as a global inhibitor of heme insertion, possibly by inhibiting a common step in the process.     

Modulation of Ocular Surface Glycocalyx Barrier Function by a Galectin-3 N-terminal Deletion Mutant and Membrane-Anchored Synthetic Glycopolymers

Background

Interaction of transmembrane mucins with the multivalent carbohydrate-binding protein galectin-3 is critical to maintaining the integrity of the ocular surface epithelial glycocalyx. This study aimed to determine whether disruption of galectin-3 multimerization and insertion of synthetic glycopolymers in the plasma membrane could be used to modulate glycocalyx barrier function in corneal epithelial cells.

Methodology/Principal Findings

Abrogation of galectin-3 biosynthesis in multilayered cultures of human corneal epithelial cells using siRNA, and in galectin-3 null mice, resulted in significant loss of corneal barrier function, as indicated by increased permeability to the rose bengal diagnostic dye. Addition of β-lactose, a competitive carbohydrate inhibitor of galectin-3 binding activity, to the cell culture system, transiently disrupted barrier function. In these experiments, treatment with a dominant negative inhibitor of galectin-3 polymerization lacking the N-terminal domain, but not full-length galectin-3, prevented the recovery of barrier function to basal levels. As determined by fluorescence microscopy, both cellobiose- and lactose-containing glycopolymers incorporated into apical membranes of corneal epithelial cells, independently of the chain length distribution of the densely glycosylated, polymeric backbones. Membrane incorporation of cellobiose glycopolymers impaired barrier function in corneal epithelial cells, contrary to their lactose-containing counterparts, which bound to galectin-3 in pull-down assays.

Conclusions/Significance

These results indicate that galectin-3 multimerization and surface recognition of lactosyl residues is required to maintain glycocalyx barrier function at the ocular surface. Transient modification of galectin-3 binding could be therapeutically used to enhance the efficiency of topical drug delivery.     

Combination of sulfamethoxazole and selenium in anticancer therapy: a novel approach

Sulfonamides have been reported to possess substantial antitumor activity as they act as carbonic anhydrase inhibitors. In addition, selenium appears to have a protective effect at various stages of cancer due to its antioxidant property, enhanced carcinogen detoxification, inhibition of cell invasion, and by inhibiting angiogenesis. Here, in the present study we aimed to evaluate and synergize the cytotoxic activity of sulfonamide and selenium (SM+SE) as effective therapy in the treatment of DENA-induced HCC. Hepatocarcinogeneis was induced by a single intraperitoneal injection of diethylnitrosamine (DENA) (200 mg/kg) in phosphate buffer. 30 Male Wistar rats used in this study were divided randomly into five equal groups (n = 6). DENA-administered animals showed significant alteration (p < 0.001) in liver-specific enzymes—glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), and Alpha fetoproteins (AFP), and also induced severe histopathological changes in the hepatic tissues. Interestingly, treatment with (SE+SE) (SM 30 mg/kg + SE 3 mg/kg) significantly reduced (P < 0.001, P < 0.001, P < 0.001, P < 0.001) the elevated AFP, SGOT, SGPT, and ALP levels, respectively, suggesting that combination therapy of SM+SE has a potential to treat DENA-induced liver damage.     

Substrate utilization of stress tolerant methylotrophs isolated from revegetated heavy metal polluted coalmine spoil

We analyzed methylotrophs in Bina natural vegetation (BNV), and revegetated overburden dump of four (ROBD4) and 12 years (ROBD12), at Bina coal mine in Sonbhadra district. The cultured strains identified as Pseudomonas, Acinetobacter, Stenotrophomonas and Cellvibrio (γ-Proteobacteria), Methylophilus, Ralstonia, Burkholderia (α-Proteobacteria) Methylobacterium and Inquilinus (β-Proteobacteria), Bacillus (Firmicutes) and Flexibacter (Sphingobacteria) in their 16s rRNA gene sequence similarity. The strains differed in citrate, lactose, formate, urea and xylose utilization. Methanol utilization by Stenotrophomonas, Inquilinus, Cellvibrio and Flexibacter is for first time. The preferred N- sources were proline, glutamate and nitrate for most of the strains. All strains tolerated (2.5 % NaCl) and SDS (0.2 %); 16 strains survived in crystal violet (0.01 %) and nine strains in sodium azide (0.02 %. Methylotrophic population trend was BNV > ROBD12 > ROBD4. The presence of majority of strain of BNV at ROBD12 and ROBD4 indicated restoration of soil methylotrophic functional diversity in revegetated dumps.