Lactose-Enhanced Cellulase Production by Microbacterium sp. Isolated from Fecal Matter of Zebra (Equus zebra)

A cellulase-producing bacterial strain designated Z5 was isolated from the fecal matter of Zebra (Equus zebra). The strain was identified as Microbacterium sp. on the basis of 16S rDNA sequence analysis. The effect of substrates like CMC, avicel, starch, maltose, sucrose, glucose, fructose, galactose, and lactose on cellulase production was also determined. Lactose as the sole carbon source induced cellulase production in this bacterial strain and a positive synergistic effect of lactose and CMC was also observed with enhancement of 3-4 times in cellulase activity. The optimum cellulase production was recorded with 3% CMC and 1% lactose when added individually in the Omeliansky's medium. The optimum temperature and time for cellulase production by this bacterial strain was 37°C and 10 days, respectively. To our knowledge this is the first report on enhancement of cellulase production by lactose in the Microbacterium sp.     

Cardiac Specific Expression of Threonine 5 to Alanine Mutant Sarcolipin Results in Structural Remodeling and Diastolic Dysfunction

The functional importance of threonine 5 (T5) in modulating the activity of sarcolipin (SLN), a key regulator of sarco/endoplasmic reticulum (SR) Ca²⁺ ATPase (SERCA) pump was studied using a transgenic mouse model with cardiac specific expression of threonine 5 to alanine mutant SLN (SLNT5A). In these transgenic mice, the SLNT5A protein replaces the endogenous SLN in atria, while maintaining the total SLN content. The cardiac specific expression of SLNT5A results in severe cardiac structural remodeling accompanied by bi-atrial enlargement. Biochemical analyses reveal a selective downregulation of SR Ca²⁺ handling proteins and a reduced SR Ca²⁺ uptake both in atria and in the ventricles. Optical mapping analysis shows slower action potential propagation in the transgenic mice atria. Doppler echocardiography and hemodynamic measurements demonstrate a reduced atrial contractility and an impaired diastolic function. Together, these findings suggest that threonine 5 plays an important role in modulating SLN function in the heart. Furthermore, our studies suggest that alteration in SLN function can cause abnormal Ca²⁺ handling and subsequent cardiac remodeling and dysfunction.     

Acquisition of ionic copper by the bacterial outer membrane protein OprC through a novel binding site

Copper, while toxic in excess, is an essential micronutrient in all kingdoms of life due to its essential role in the structure and function of many proteins. Proteins mediating ionic copper import have been characterised in detail for eukaryotes, but much less so for prokaryotes. In particular, it is still unclear whether and how gram-negative bacteria acquire ionic copper. Here, we show that Pseudomonas aeruginosa OprC is an outer membrane, TonB-dependent transporter that is conserved in many Proteobacteria and which mediates acquisition of both reduced and oxidised ionic copper via an unprecedented CxxxM-HxM metal binding site. Crystal structures of wild-type and mutant OprC variants with silver and copper suggest that acquisition of Cu(I) occurs via a surface-exposed “methionine track” leading towards the principal metal binding site. Together with whole-cell copper quantitation and quantitative proteomics in a murine lung infection model, our data identify OprC as an abundant component of bacterial copper biology that may enable copper acquisition under a wide range of conditions.

How do Gram-negative bacteria acquire copper? This study shows that the outer membrane protein OprC from Pseudomonas aeruginosa is abundant during infection and mediates highly selective acquisition of both copper redox states via an extracellular "methionine track" and an unprecedented near-irreversible binding site.     

Physiological and fermentation properties of <Emphasis Type="Italic">Bacillus coagulans</Emphasis> and a mutant lacking fermentative lactate dehydrogenase activity

Bacillus coagulans, a sporogenic lactic acid bacterium, grows optimally at 50–55°C and produces lactic acid as the primary fermentation product from both hexoses and pentoses. The amount of fungal cellulases required for simultaneous saccharification and fermentation (SSF) at 55°C was previously reported to be three to four times lower than for SSF at the optimum growth temperature for Saccharomyces cerevisiae of 35°C. An ethanologenic B. coagulans is expected to lower the cellulase loading and production cost of cellulosic ethanol due to SSF at 55°C. As a first step towards developing B. coagulans as an ethanologenic microbial biocatalyst, activity of the primary fermentation enzyme L-lactate dehydrogenase was removed by mutation (strain Suy27). Strain Suy27 produced ethanol as the main fermentation product from glucose during growth at pH 7.0 (0.33 g ethanol per g glucose fermented). Pyruvate dehydrogenase (PDH) and alcohol dehydrogenase (ADH) acting in series contributed to about 55% of the ethanol produced by this mutant while pyruvate formate lyase and ADH were responsible for the remainder. Due to the absence of PDH activity in B. coagulans during fermentative growth at pH 5.0, the l-ldh mutant failed to grow anaerobically at pH 5.0. Strain Suy27-13, a derivative of the l-ldh mutant strain Suy27, that produced PDH activity during anaerobic growth at pH 5.0 grew at this pH and also produced ethanol as the fermentation product (0.39 g per g glucose). These results show that construction of an ethanologenic B. coagulans requires optimal expression of PDH activity in addition to the removal of the LDH activity to support growth and ethanol production.     

Design, synthesis and anti-microbial activity of 1H-pyrazole carboxylates

In a SAR study, we have synthesized a few 1H-pyrazole carboxylate related microbicides using Vilsmeier reagent. The anti-microbial screening results of 1H-pyrazole-3-carboxylate are reported here for the first time. The effect of 1H-pyrazole carboxylates on the mycelial growth of plant pathogenic fungi is revealed. The first X-ray structure in the family of microbicidal 1H-pyrazole-4-carboxylates is presented.     

Male reproductive toxicity of vincristine: ultrastructural changes in the epididymal epithelial apical cell

The toxic effect of vincristine on the apical cells of the rat caput epididymis was investigated. The drug was administered at 20 and 40 microg/kg body weight daily for 15 days. Light microscopy using semithin sections, and transmission electron microscopy, of the caput epididymis were undertaken. The results revealed that the basal region of the apical cell was in contact with the basement membrane and the luminal end took part in endocytosis. The apical cells reflected a dose-dependent response to vincristine (VCR) treatment. In general the changes included protrusion of the apical ends deep into the lumen, with the nucleus of the cell located in such protruded ends, and an increase in the abundance of lysosomal bodies and multivesicular bodies. These changes reflected the physiological response of the apical cell to VCR treatment rather than toxic manifestations.     

The açaí flavonoid velutin is a potent anti-inflammatory agent: blockade of LPS-mediated TNF-α and IL-6 production through inhibiting NF-κB activation and MAPK pathway

Recent studies have shown that some flavonoids are modulators of proinflammatory cytokine production. In this study, velutin, a unique flavone isolated from the pulp of açaí fruit (Euterpe oleracea Mart.), was examined for its effects in reducing lipopolysaccharide-induced proinflammatory cytokine tumor necrosis factor (TNF)-α and interleukin (IL)-6 production in RAW 264.7 peripheral macrophages and mice peritoneal macrophages. Three other structurally similar and well-studied flavones, luteolin, apigenin and chrysoeriol, were included as controls and for comparative purposes. Velutin exhibited the greatest potency among all flavones in reducing TNF-α and IL-6 production. Velutin also showed the strongest inhibitory effect in nuclear factor (NF)-κB activation (as assessed by secreted alkaline phosphatase reporter assay) and exhibited the greatest effects in blocking the degradation of inhibitor of NF-κB as well as in inhibiting mitogen-activated protein kinase p38 and JNK phosphorylation; all of these are important signaling pathways involved in production of TNF-α and IL-6. The present study led to the discovery of a strong anti-inflammatory flavone, velutin. This compound effectively inhibited the expression of proinflammatory cytokines TNF-α and IL-6 in low micromole levels by inhibiting NF-κB activation and p38 and JNK phosphorylation.     

Toll-like receptors and their role in animal reproduction

Toll-like receptors (TLRs) are evolutionarily conserved innate immune receptors that recognize pathogen specific molecular pattern (PAMPs) in an efficient, non-self-reactive manner and initiate specific immune signaling that culminates in triggering antigen-specific adaptive responses. Different TLR genes in domestic animal species have been characterized and accumulating evidence from recent studies indicates an extended role for TLR signaling in reproductive physiology. In females, TLRs have been implicated in the regulation of ovulation, fertilization, gestation and parturition, as well as in pathological conditions such as endometritis and mastitis. In males, TLRs play a role in steroidogenesis and spermatogenesis. Use of TLR agonists has also been shown to be effective in the treatment of certain reproductive tract infections. Moreover, gene polymorphisms in TLRs have been associated with mastitis providing evidence that TLRs can potentially be exploited as markers in future breeding programs. The aim of this review is to provide a comprehensive treatise on role of TLRs in male and female reproductive physiology and associated pathology in domestic livestock.