Regulation of the phosphate (Pi) concentration in UMR 106 osteoblast-like cells: Effect of Pi,Na+ and K+

Osteoblast-like cells possess Na-dependent transporters which accumulate orthophosphate (Pi) from the extracellular medium. This may be important in bone formation. Here we describe parallel measurements of Pi uptake and cellular [Pi] in such cells from the rat (UMR 106–01 and UMR 106–06) and human (OB), and in non-osteoblastic human fibroblasts (Detroit 532 (DET)). In UMR 106–01, cellular [Pi] was weakly dependent on extracellular [Pi] and higher than expected from passive transport alone. [³²Pi]-uptake was inhibited by Na deprivation, but paradoxically increased on K deprivation. With Na, 87 per cent of cellular ³²P was found in organic phosphorus pools after only 5 min. Na deprivation also decreased cellular [Pi], in both UMR 106–01 and DET, but the decrease was smaller than that in [³²Pi]-uptake. Ouabain decreased [³²Pi]-uptake and cellular [Pi] in DET, but not in UMR 106–01. Regulation of cellular [Pi] is therefore at least partly dependent on Na/Pi co-transport, but this does not seem to be an exclusive property of osteoblasts.     

Detection of Schistosoma mansoni in bronchoalveolar lavage fluid. A case report.

BACKGROUND: Bronchoalveolar lavage (BAL) is a useful tool in the diagnosis of bacterial, viral, fungal and parasitic pulmonary infections. There have been rare reports of parasitic infestations in bronchoalveolar lavage fluid. This is the first case report on detecting a Schistosoma ova in BAL fluid. CASE: A 40-year-old, Egyptian male presented with a fever and productive cough. He had a right pleural effusion and segmental collapse of the right lower lobe. BAL fluid showed several ova of Schistosoma mansoni and established the diagnosis of schistosomiasis. Abdominal ultrasound revealed mild hepatic cirrhosis. CONCLUSION: Schistosomiasis should be considered in the differential diagnosis of pulmonary problems in patients with disseminated disease in endemic areas.     

Glutathione metabolizing enzymes and oxidative stress in ferric nitrilotriacetate mediated hepatic injury

Summary

Glutathione (GSH) plays several important roles in the protection of cells against oxidative damage, particularly following exposure to xenobiotics. Ferric nitrilotriacetate (Fe-NTA) is a potent depletor of GSH and also enhances tissue lipid peroxidation. In this study, we show the effect of Fe-NTA treatment on hepatic GSH and some of the glutathione metabolizing enzymes, oxidant generation and liver damage. The level of hepatic GSH and the activities of glutathione reductase, glutathione S-transferase, glutathione peroxidase, and glucose 6-phosphate dehydrogenase all decrease following Fe-NTA administration. In these parameters the maximum decrease occurred at 12 h following Fe-NTA treatment. In contrast, γ-glutamyl transpeptidase was increased at this time. Not surprisingly, the increase in the activity of γ-glutamyl transpeptidase and decreases in GSH, glutathione peroxidase, glutathione reductase, glucose 6-phosphate dehydrogenase and glutathione S-transferase were found to be dependent on the dose of Fe-NTA administered. Fe-NTA administration also enhances the production of H₂O₂ and increases hepatic lipid peroxidation. Parallel to these changes, Fe-NTA enhances liver damage as evidenced by increases in serum transaminases. Once again, the liver damage is dependent on the dose of Fe-NTA and is maximal at 12 h. Pretreatment of animals with antioxidant, butylated hydroxy anisole (BHA), protects against Fe-NTA-mediated hepatotoxicity further supporting the involvement of oxidative stress in Fe-NTA-mediated hepatic damage. In aggregate, our results indicate that Fe-NTA administration eventuates in decreased hepatic GSH, a fall in the activities of glutathione metabolizing enzymes and excessive production of oxidants, all of which are involved in the cascade of events leading to iron-mediated hepatic injury.     

Biological properties of streptococcal cell-wall particles. 3. Dermonecrotic reaction to cell-wall mucopeptides

Abdulla, Essa M. (University of North Carolina School of Medicine, Chapel Hill), and John H. Schwab. Biological properties of streptococcal cell-wall particles. III. Dermonecrotic reaction to cell-wall mucopeptides. J. Bacteriol. 91:374-383. 1966.-Intradermal injection of rabbits and guinea pigs with mucopeptide suspensions produced an acute necrotic lesion which reached maximal severity within 24 hr and gradually subsided with scar formation. Necrosis was evident within 4 hr after injection of 100 mug, and an indurated area (10 x 10 mm) was produced with as little as 5.0 mug. Mucopeptides from six bacterial strains were studied. Comparison of cell walls and derived mucopeptides showed that the acute necrotic lesion tended to be more severe as the residual polysaccharide was decreased. Hyperimmunization with mucopeptide reduced the acute reaction, with evidence of immunological specificity. Incubation with lysozyme also modified the reaction in relation to extent of digestion. Toxicity was related to particle size, since extended sonic vibration decreased activity. Histological sections showed intense accumulations of polymorphonuclear leukocytes, along with altered collagen. A chronic nodular lesion appeared about 7 days after injection of the intact cell-wall fragments. In contrast to the acute necrotic reaction, this lesion was rarely produced by the mucopeptide separated from polysaccharide.     

松萝酸研究进展

自从松萝酸于1844年第一次被分离出来,它已经成为研究最广泛的地衣物质之一。对于松萝酸的抗菌功能、化学性质及其在医药、环境监控等各个领域的应用研究,可见于各种外文文献的报道。美国、日本及德国的应用研究较多;而中国、智利、南斯拉夫、印度尼西亚等国仍然在致力于松萝酸的提取、抗菌、抗病毒等基础方面的研究。中文文献不多。目前发现松萝酸只存在于地衣中,在以下种属中较为丰富：树发属、石蕊属、茶渍衣属、松萝属、树花属及扁枝衣。     

Antibacterial and Cytotoxic Efficacy of Extracellular Silver Nanoparticles Biofabricated from Chromium Reducing Novel OS4 Strain of Stenotrophomonas maltophilia

Biofabricated metal nanoparticles are generally biocompatible, inexpensive, and ecofriendly, therefore, are used preferably in industries, medical and material science research. Considering the importance of biofabricated materials, we isolated, characterized and identified a novel bacterial strain OS4 of Stenotrophomonas maltophilia (GenBank: {"type":"entrez-nucleotide","attrs":{"text":"JN247637.1","term_id":"341941875","term_text":"JN247637.1"}}JN247637.1). At neutral pH, this Gram negative bacterial strain significantly reduced hexavalent chromium, an important heavy metal contaminant found in the tannery effluents and minings. Subsequently, even at room temperature the supernatant of log phase grown culture of strain OS4 also reduced silver nitrate (AgNO₃) to generate nanoparticles (AgNPs). These AgNPs were further characterized by UV–visible, Nanophox particle size analyzer, XRD, SEM and FTIR. As evident from the FTIR data, plausibly the protein components of supernatant caused the reduction of AgNO₃. The cuboid and homogenous AgNPs showed a characteristic UV-visible peak at 428 nm with average size of ∼93 nm. The XRD spectra exhibited the characteristic Bragg peaks of 111, 200, 220 and 311 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. From the nanoparticle release kinetics data, the rapid release of AgNPs was correlated with the particle size and increasing surface area of the nanoparticles. A highly significant antimicrobial activity against medically important bacteria by the biofabricated AgNPs was also revealed as decline in growth of Staphylococcus aureus (91%), Escherichia coli (69%) and Serratia marcescens (66%) substantially. Additionally, different cytotoxic assays showed no toxicity of AgNPs to liver function, RBCs, splenocytes and HeLa cells, hence these particles were safe to use. Therefore, this novel bacterial strain OS4 is likely to provide broad spectrum benefits for curing chromium polluted sites, for biofabrication of AgNPs and ultimately in the nanoparticle based drug formulation for the treatment of infectious diseases.     

Propylisopropylacetic acid (PIA), a constitutional isomer of valproic acid,uncompetitively inhibits arachidonic acid acylation by rat acyl-CoA synthetase 4: A potential drug for bipolar disorder

Background

Mood stabilizers used for treating bipolar disorder (BD) selectively downregulate arachidonic acid (AA) turnover (deacylation–reacylation) in brain phospholipids, when given chronically to rats. In vitro studies suggest that one of these, valproic acid (VPA), which is teratogenic, reduces AA turnover by inhibiting the brain long-chain acyl-CoA synthetase (Acsl)4 mediated acylation of AA to AA-CoA. We tested whether non-teratogenic VPA analogues might also inhibit Acsl4 catalyzed acylation, and thus have a potential anti-BD action.

Methods

Rat Acsl4-flag protein was expressed in Escherichia coli, and the ability of three VPA analogues, propylisopropylacetic acid (PIA), propylisopropylacetamide (PID) and N-methyl-2,2,3,3-tetramethylcyclopropanecarboxamide (MTMCD), and of sodium butyrate, to inhibit conversion of AA to AA-CoA by Acsl4 was quantified using Michaelis–Menten kinetics.

Results

Acsl4-mediated conversion of AA to AA-CoA in vitro was inhibited uncompetitively by PIA, with a K_i of 11.4 mM compared to a published K_i of 25 mM for VPA, while PID, MTMCD and sodium butyrate had no inhibitory effect.

Conclusions

PIA's ability to inhibit conversion of AA to AA-CoA by Acsl4 in vitro suggests that, like VPA, PIA may reduce AA turnover in brain phospholipids in unanesthetized rats, and if so, may be effective as a non-teratogenic mood stabilizer in BD patients.     

The AAA ATPase VPS4/SKD1 Regulates Endosomal Cholesterol Trafficking Independently of ESCRT‐III

The exit of low‐density lipoprotein derived cholesterol (LDL‐C) from late endosomes (LE)/lysosomes (Ly) is mediated by Niemann–Pick C1 (NPC1), a multipass integral membrane protein on the limiting membranes of LE/Ly, and by NPC2, a cholesterol‐binding protein in the lumen of LE/Ly. NPC2 delivers cholesterol to the N‐terminal domain of NPC1, which is believed to insert cholesterol into the limiting membrane for subsequent transport to other subcellular organelles. Few cytoplasmic factors have been identified to govern cholesterol efflux from LE/Ly, and much less is known about the underlying molecular mechanisms. Here we establish VPS4, an AAA ATPase that has a well‐established role in disassembling the ESCRT (endosomal sorting complex required for transport)‐III polymer, as an important regulator of endosomal cholesterol transport. Knocking down VPS4 in HeLa cells resulted in prominent accumulation of LDL‐C in LE/Ly, and disrupted cholesterol homeostatic responses at the endoplasmic reticulum. The level and localization of NPC1 and NPC2 appeared to be normal in VPS4 knockdown cells. Importantly, depleting any of the ESCRT‐III components did not exert a significant effect on endosomal cholesterol transport. Our results thus identify an important cytoplasmic regulator of endosomal cholesterol trafficking and represent the first functional separation of VPS4 from ESCRT‐III.     

A comparative study of bacterial diversity based on culturable and culture-independent techniques in the rhizosphere of maize (Zea mays L.)

ObjectiveMaize is an important crop for fodder, food and feed industry. The present study explores the plant-microbe interactions as alternative eco-friendly sustainable strategies to enhance the crop yield.MethodologyBacterial diversity was studied in the rhizosphere of maize by culture-dependent and culture-independent techniques by soil sampling, extraction of DNA, amplification of gene of interest, cloning of desired fragment and library construction.ResultsCulturable bacteria were identified as Achromobacter, Agrobacterium, Azospirillum, Bacillus, Brevibacillus, Bosea, Enterobacter, Microbacterium, Pseudomonas, Rhodococcus, Stenotrophomonas and Xanthomonas genera. For culture-independent approach, clone library of 16S ribosomal RNA gene was assembled and 100 randomly selected clones were sequenced. Majority of the sequences were related to Firmicutes (17%), Acidobacteria (16%), Actinobacteria (17%), Alpha-Proteobacteria (7%), Delta-proteobacteria (4.2%) and Gemmatimonadetes (4.2%) However, some of the sequences (30%) were novel that showed no homologies to phyla of cultured bacteria in the database. Diversity of diazotrophic bacteria in the rhizosphere investigated by analysis of PCR-amplified nifH gene sequence that revealed abundance of sequences belonging to genera Azoarcus (25%), Aeromonas (10%), Pseudomonas (10%). The diazotrophic genera Azotobacter, Agrobacterium and Zoogloea related nifH sequences were also detected but no sequence related to Azospirillum was found showing biasness of the growth medium rather than relative abundance of diazotrophs in the rhizosphere.ConclusionThe study provides a foundation for future research on focussed isolation of the Azoarcus and other diazotrophs found in higher abundance in the rhizosphere.