A novel compound from the marine bacterium Bacillus pumilus S6-15 inhibits biofilm formation in gram-positive and gram-negative species

Biofilm formation is a critical problem in nosocomial infections and in the aquaculture industries and biofilms show high resistance to antibiotics. The aim of the present study was to reveal a novel anti-biofilm compound from marine bacteria against antibiotic resistant gram-positive and gram-negative biofilms. The bacterial extract (50 μg ml(-1)) of S6-01 (Bacillus indicus = MTCC 5559) showed 80-90% biofilm inhibition against Escherichia coli, Shigella flexneri, Proteus mirabilis and S6-15 (Bacillus pumilus = MTCC 5560) showed 80-95% biofilm inhibition against all the 10 tested organisms. Furthermore, they also reduced the hydrophobicity index and extracellular polymeric substances (EPS) production. Structural elucidation of the active principle in S6-15 using GC-MS, (1)H NMR, and (13)C NMR spectral data revealed it to be 4-phenylbutanoic acid. This is the first report of 4-phenylbutanoic acid as a natural product. The purified compound (10-15 μg ml(-1)) showed potential activity against a wide range of biofilms. This study for the first time, reports a novel anti-biofilm compound from a marine bacterium with wide application in medicine and the aquaculture industry.     

A blueberry-enriched diet attenuates nephropathy in a rat model of hypertension via reduction in oxidative stress

Objective and Background

To assess renoprotective effects of a blueberry-enriched diet in a rat model of hypertension. Oxidative stress (OS) appears to be involved in the development of hypertension and related renal injury. Pharmacological antioxidants can attenuate hypertension and hypertension-induced renal injury; however, attention has shifted recently to the therapeutic potential of natural products as antioxidants. Blueberries (BB) have among the highest antioxidant capacities of fruits and vegetables.

Methods and Results

Male spontaneously hypertensive rats received a BB-enriched diet (2% w/w) or an isocaloric control diet for 6 or 12 weeks or 2 days. Compared to controls, rats fed BB-enriched diet for 6 or 12 weeks exhibited lower blood pressure, improved glomerular filtration rate, and decreased renovascular resistance. As measured by electron paramagnetic resonance spectroscopy, significant decreases in total reactive oxygen species (ROS), peroxynitrite, and superoxide production rates were observed in kidney tissues in rats on long-term dietary treatment, consistent with reduced pathology and improved function. Additionally, measures of antioxidant status improved; specifically, renal glutathione and catalase activities increased markedly. Contrasted to these observations indicating reduced OS in the BB group after long-term feeding, similar measurements made in rats fed the same diet for only 2 days yielded evidence of increased OS; specifically, significant increases in total ROS, peroxynitrite, and superoxide production rates in all tissues (kidney, brain, and liver) assayed in BB-fed rats. These results were evidence of “hormesis” during brief exposure, which dissipated with time as indicated by enhanced levels of catalase in heart and liver of BB group.

Conclusion

Long-term feeding of BB-enriched diet lowered blood pressure, preserved renal hemodynamics, and improved redox status in kidneys of hypertensive rats and concomitantly demonstrated the potential to delay or attenuate development of hypertension-induced renal injury, and these effects appear to be mediated by a short-term hormetic response.     

EphA2 Mutation in Lung Squamous Cell Carcinoma Promotes Increased Cell Survival,Cell Invasion,Focal Adhesions,and Mammalian Target of Rapamycin Activation

Non-small cell lung cancer (NSCLC) has a poor prognosis and improved therapies are needed. Expression of EphA2 is increased in NSCLC metastases. In this study, we investigated EphA2 mutations in NSCLC and examined molecular pathways involved in NSCLC. Tumor and cell line DNA was sequenced. One EphA2 mutation was modeled by expression in BEAS2B cells, and functional and biochemical studies were conducted. A G391R mutation was detected in H2170 and 2/28 squamous cell carcinoma patient samples. EphA2 G391R caused constitutive activation of EphA2 with increased phosphorylation of Src, cortactin, and p130^Cas. Wild-type (WT) and G391R cells had 20 and 40% increased invasiveness; this was attenuated with knockdown of Src, cortactin, or p130^Cas. WT and G391R cells demonstrated a 70% increase in focal adhesion area. Mammalian target of rapamycin (mTOR) phosphorylation was increased in G391R cells with increased survival (55%) compared with WT (30%) and had increased sensitivity to rapamycin. A recurrent EphA2 mutation is present in lung squamous cell carcinoma and increases tumor invasion and survival through activation of focal adhesions and actin cytoskeletal regulatory proteins as well as mTOR. Further study of EphA2 as a therapeutic target is warranted.     

Evaluation of the activity of CYP2C19 in Gujrati and Marwadi subjects living in Mumbai (Bombay)

Background  

Inherited differences in the metabolism and disposition of drugs, and genetic polymorphisms in the targets of drug therapy (e.g., receptors), can greatly influence efficacy and toxicity of medications. Marked interethnic differences in CYP2C19 (a member of the cytochrome P-450 enzyme superfamily catalyzing phase I drug metabolism) which affects the metabolism of a number of clinically important drugs have been documented. The present study evaluated the activity of CYP2C19 in normal, healthy Gujrati and Marwadi subjects by phenotyping (a western Indian population).     

Novel whole-cell Reporter Assay for Stress-Based Classification of Antibacterial Compounds Produced by Locally Isolated Bacillus spp.

Reporter bacteria are beneficial for the rapid and sensitive screening of cultures producing peptide antibiotics, which can be an addition or alternative to the established antibiotics. This study was carried out to validate the usability of specific reporter strains for the target mediated identification of antibiotics produced by native Bacillus spp. isolated from different food sources. During preliminary classification, cell wall stress causing Bacillus isolates were screened by using reporter strain Bacillus subtilis BSF2470. The isolates which induced cell wall stress were further characterized for their specific mode of action by using other B. subtilis reporter strains (TMB 488, TMB 299 and TMB 279). The isolate B. licheniformis N12 was found to produce bacitracin confirmed by the response to reporter strain B. subtilis TMB 279 and by putative identification of bacitracin biosynthetic loci. The other isolate B. subtilis EC1 also induced B. subtilis TMB 279, but does not possess the bacitracin gene cluster indicating that it can be a novel, bacitracin like antibiotic. The different but related subsets of peptide antibiotics that bind the pyrophosphate moiety of the lipid carrier of cell wall biosynthesis can be identified using this whole cell based reporter strains.     

TNF-induced mitochondrial damage: a link between mitochondrial complex I activity and left ventricular dysfunction

Mitochondrial damage is implicated in the progression of cardiac disease. Considerable evidence suggests that proinflammatory cytokines induce oxidative stress and contribute to cardiac dysfunction. This study was conducted to determine whether a TNF-induced increase in superoxide (O₂^?) contributes to mitochondrial damage in the left ventricle (LV) by impairing respiratory complex I activity. We employed an electron paramagnetic resonance (EPR) method to measure O₂^? and oxygen consumption in mitochondrial respiratory complexes, using an oxygen label. Adult male Sprague–Dawley rats were divided into four groups: control, TNF treatment (ip), TNF+ apocynin (APO; 200 μmol/kg bw, orally), and TNF+ Tempol (Temp; 300 μmol/kg bw, orally). TNF was injected daily for 5 days. Rats were sacrificed, LV tissue was collected, and mitochondria were isolated for EPR studies. Total LV ROS production was significantly higher in TNF animals than in controls; APO or Temp treatment ameliorated TNF-induced LV ROS production. Total mitochondrial ROS production was significantly higher in the TNF and TNF+ APO groups than in the control and TNF+ Temp groups. These findings suggest that TNF alters the cellular redox state, reduces the expression of four complex I subunits by increasing mitochondrial O₂^? production and depleting ATP synthesis, and decreases oxygen consumption, thereby resulting in mitochondrial damage and leading to LV dysfunction.     

Non-random organization of the Biomphalaria glabrata genome in interphase Bge cells and the spatial repositioning of activated genes in cells co-cultured with Schistosomamansoni

Biomphalaria glabrata is a major intermediate host for the parasitic trematode Schistosoma mansoni, a causative agent of human schistosomiasis. To decipher the molecular basis of this host-parasite interaction, the Bge embryonic cell line provides a unique in vitro model system to assess whether interactions between the snail and parasite affect the cell and genome biology in either organism. The organization of the B. glabrata genome in Bge cells was studied using image analysis through positioning territories of differently sized chromosomes within cell nuclei. The snail chromosome territories are similar in morphology as well as in non-random radial positioning as those found in other derived protostome and deuterostome organisms. Specific monitoring of four gene loci, piwi, BgPrx, actin and ferritin, revealed non-random radial positioning of the genome. This indicates that specific parts of the snail genome reside in reproducible nuclear addresses. To determine whether exposure to parasite is reflected in genome organization, the interphase spatial positioning of genes was assessed after co-culturing Bge cells with either normal or irradiation attenuated miracidia for 30 min to 24 h. The loci of actin and ferritin, genes that are up-regulated in the snail when subjected to infection, were visualized by fluorescence in situ hybridisation (FISH) and their radial nuclear positions i.e. their position in the interphase nucleus with respect to the nuclear edge/envelope, mapped. Interestingly, large scale gene repositioning correlated to temporal kinetics of gene expression levels in Bge cells co-cultured with normal miracidia while irradiated parasites failed to elicit similar gene expression or gene loci repositioning as demonstrated using the ferritin gene. This indicates that normal but not attenuated schistosomes provide stimuli that evoke host responses that are reflected in the host’s nuclear architecture. We believe that this is not only the first time that gene-repositioning studies have been attempted in a mollusc but also demonstrates a parasite influencing the interphase genome organization of its host.     

mTOR Signaling Regulates Nucleolar Targeting of the SUMO-Specific Isopeptidase SENP3

Ribosome biogenesis is a multistep cellular pathway that involves more than 200 regulatory components to ultimately generate translation-competent 80S ribosomes. The initial steps of this process, particularly rRNA processing, take place in the nucleolus, while later stages occur in the nucleoplasm and cytoplasm. One critical factor of 28S rRNA maturation is the SUMO-isopeptidase SENP3. SENP3 tightly interacts with the nucleolar scaffold protein NPM1 and is associated with nucleolar 60S preribosomes. A central question is how changes in energy supply feed into the regulation of ribosome maturation. Here, we show that the nutrient-sensing mTOR kinase pathway controls the nucleolar targeting of SENP3 by regulating its interaction with NPM1. We define an N-terminal domain in SENP3 as the critical NPM1 binding region and provide evidence that mTOR-mediated phosphorylation of serine/threonine residues within this region fosters the interaction of SENP3 with NPM1. The inhibition of mTOR triggers the nucleolar release of SENP3, thereby likely compromising its activity in rRNA processing. Since mTOR activity is tightly coupled to nutrient availability, we propose that this pathway contributes to the adaptation of ribosome maturation in response to the cellular energy status.     

Fungal utilization of a known and safe macroalga for pigment production using solid-state fermentation

Saccharina (Laminaria) japonica, a safe, cheap, and readily available macroalga can be used as a substrate for various microbial fermentations. This work investigated the feasibility of S. japonica as a substrate for production of pigments by the fungus Talaromyces amestolkiae GT11 in solid-state fermentation without additional salt and/or nitrogen sources. Under optimized conditions, the pigment exhibited maximum absorption spectrum at 410 (yellow) and 510 nm (red), and the pigment yield of 1,153.5 (yellow) and 506.2 (red) OD units g^?1 of dry fermented substrate were achieved with a particle size of 1.0 mm and pH 7, although visually the pigment was reddish in color. The optimum incubation period, pH, moisture, inoculum size, and temperature were observed to be at 192 h, pH 7.0, 80 % (w/w) moisture, 1.8?×?10⁶ spores mL^?1 of inoculum g^-1 of dry substrate and 28 °C. Hence, this study indicates the suitability of utilization of S. japonica as a substrate for natural pigment production by T. amestolkiae GT11 which can be used in food, cosmetics and pharmaceutical industries for various applications.