Substrate specificities in hydrolysis of polyhydroxyalkanoates by microbial esterases

Summary Enzymatic degradations of 5 different polyhydroxyalkanoates (PHA) were investigated at 37°C in the aqueous solutions (pH 7.4) containing different microbial enzymes of 16 lipases and 5 PHA depolymerases. The substrate specificities of microbial PHA depolymerases on hydrolysis of polyhydroxyalkanoates were distinguished from those of microbial lipases.     

Oxidative stress and cannabinoid receptor expression in type‐2 diabetic rat pancreas following treatment with Δ9‐THC

The objectives of study were (a) to determine alteration of feeding, glucose level and oxidative stress and (b) to investigate expression and localization of cannabinoid receptors in type‐2 diabetic rat pancreas treated with Δ⁹‐tetrahydrocannabinol (Δ⁹‐THC). Rats were randomly divided into four groups: control, Δ⁹‐THC, diabetes and diabetes + Δ⁹‐THC groups. Diabetic rats were treated with a single dose of nicotinamide (85 mg/kg) 15 min before injection of streptozotocin (65 mg/kg). Δ⁹‐THC was administered intraperitoneally at 3 mg/kg/day for 7 days. Body weights and blood glucose level of rats in all groups were measured on days 0, 7, 14 and 21. On day 15 after the Δ⁹‐THC injections, pancreatic tissues were removed. Blood glucose levels and body weights of diabetic rats treated with Δ⁹‐THC did not show statistically significant changes when compared with the diabetic animals on days 7, 14 and 21. Treatment with Δ⁹‐THC significantly increased pancreas glutathione levels, enzyme activities of superoxide dismutase and catalase in diabetes compared with non‐treatment diabetes group. The cannabinoid 1 receptor was found in islets, whereas the cannabinoid 2 receptor was found in pancreatic ducts. Their localization in cells was both nuclear and cytoplasmic. We can suggest that Δ⁹‐THC may be an important agent for the treatment of oxidative damages induced by diabetes. However, it must be supported with anti‐hyperglycaemic agents. Furthermore, the present study for the first time emphasizes that Δ⁹‐THC may improve pancreatic cells via cannabinoid receptors in diabetes. The aim of present study was to elucidate the effects of Δ⁹‐THC, a natural cannabinoid receptor agonist, on the expression and localization of cannabinoid receptors, and oxidative stress statue in type‐2 diabetic rat pancreas. Results demonstrate that the cannabinoid receptors are presented in both Langerhans islets and duct regions. The curative effects of Δ⁹‐THC can be occurred via activation of cannabinoid receptors in diabetic rat pancreas. Moreover, it may provide a protective effect against oxidative damage induced by diabetes. Thus, it is suggested that Δ⁹‐THC can be a candidate for therapeutic alternatives of diabetes symptoms. Copyright © 2014 John Wiley & Sons, Ltd.     

Curcumin Acts as Post-protective Effects on Rat Hippocampal Synaptosomes in a Neuronal Model of Aluminum-Induced Toxicity

The neurotoxic effects of aluminum are generally associated with reduced antioxidant capacity, increased oxidative stress and apoptosis, which lead to the induction of neurodegenerative processes. Curcumin has a lipophilic polyphenol character and effects of antioxidant and anti-apoptotic. The present study was undertaken to examine possible aluminum exposure in rats brain synaptosomes and to investigate whether protective and therapeutic effects of curcumin on biochemical and morphological changes in both pre- and post-treated groups. Aluminum chloride (AlCl₃) at 50 µM concentration and curcumin at 5 and 10 µg/mL doses were applied to hippocampal synaptosomes of rats according to experimental design. Biochemical effects were evaluated by MTT cytotoxicity, malondialdehyde (MDA) levels, nitric oxide (NO) levels, glutathione (GSH) levels, caspase 3 activities, cytochrome c levels, DNA fragmentation values and protein levels. Morphological examinations were done by TEM analysis. AlCI₃ exposure in the synaptosomes enhanced oxidative stress, triggered apoptosis and caused ultrastructural alterations which were well reflected in the TEM images. Curcumin pre-treatment slightly ameliorated the MDA levels, NO levels, cytochrome c levels and caspase 3 activities in AlCI₃-exposed synaptosomes, but these results were not statistically significant. Furthermore, curcumin post-treatment significantly improved oxidative damage and morphological alterations, and suppressed cytochrome c and caspase 3 activities. Taken together, our data showed that curcumin had more therapeutic effects than protective effects in AlCI₃-induced neurotoxicity. Nevertheless, the therapeutic (post-protective) effects of curcumin should be further investigated in in vivo neurodegenerative models involving behavioral tests.

     

Investigation of relationship between IL-6 gene variants and hypertension in Turkish population

Hypertension (HT) is a common and life threating health problem worldwide leading to stroke, heart attack and renal failure. It is characterized by elevated blood pressure forced heart load. Human interleukin-6 (IL-6) and C- reactive protein (CRP) are known to be involved in inflammatory processes. IL-6 gene is a polymorphic gene which −174 G/C is a common and −572 G/C is a rare polymorphisms identified in promoter region. Publications on IL-6 gene polymorphisms raised the question whether this gene polymorphisms lead to susceptibility to HT or not. To investigate the effects of IL-6 gene −174 G/C (rs 1800795) and −572 G/C (rs1800796) polymorphisms on plasma IL-6 and CRP levels and their associations with hypertension disease in Turkish population we analyzed −174 G/C and −572 G/C polymorphisms and plasma IL-6 and CRP levels in 111 healthy controls and 108 hypertension patients from Adıyaman, Turkey. We determined the genotypes using polymerase chain reaction-restriction fragment length polymorphism and analyzed plasma levels of IL-6 by ELISA and CRP by automated standard biochemical methods. We have found no statistically significant differences between IL-6 gene −174 G/C and −572 G/C genotypes and allelic frequencies and IL-6 and CRP plasma levels and HT (p > 0.05). No CC genotype was found in control subjects for −572 G/C polymorphism. In conclusion, we found relation to −174 G/C and −572 G/C gene variants between neither IL-6 and CRP levels nor hypertension. The −572 G allele and GG genotype are predominant in Turkish population in Adıyaman, Turkey whereas the CC genotype is very rare.     

Accuracy of functional surfaces on comparatively modeled protein structures

Identification and characterization of protein functional surfaces are important for predicting protein function, understanding enzyme mechanism, and docking small compounds to proteins. As the rapid speed of accumulation of protein sequence information far exceeds that of structures, constructing accurate models of protein functional surfaces and identify their key elements become increasingly important. A promising approach is to build comparative models from sequences using known structural templates such as those obtained from structural genome projects. Here we assess how well this approach works in modeling binding surfaces. By systematically building three-dimensional comparative models of proteins using Modeller, we determine how well functional surfaces can be accurately reproduced. We use an alpha shape based pocket algorithm to compute all pockets on the modeled structures, and conduct a large-scale computation of similarity measurements (pocket RMSD and fraction of functional atoms captured) for 26,590 modeled enzyme protein structures. Overall, we find that when the sequence fragment of the binding surfaces has more than 45% identity to that of the template protein, the modeled surfaces have on average an RMSD of 0.5 Å, and contain 48% or more of the binding surface atoms, with nearly all of the important atoms in the signatures of binding pockets captured.     

PKC alpha mediates beta-arrestin2-dependent nephrin endocytosis in hyperglycemia

Nephrin, the key molecule of the glomerular slit diaphragm, is expressed on the surface of podocytes and is critical in preventing albuminuria. In diabetes, hyperglycemia leads to the loss of surface expression of nephrin and causes albuminuria. Here, we report a mechanism that can explain this phenomenon: hyperglycemia directly enhances the rate of nephrin endocytosis via regulation of the β-arrestin2-nephrin interaction by PKCα. We identified PKCα and protein interacting with c kinase-1 (PICK1) as nephrin-binding proteins. Hyperglycemia induced up-regulation of PKCα and led to the formation of a complex of nephrin, PKCα, PICK1, and β-arrestin2 in vitro and in vivo. Binding of β-arrestin2 to the nephrin intracellular domain depended on phosphorylation of nephrin threonine residues 1120 and 1125 by PKCα. Further, cellular knockdown of PKCα and/or PICK1 attenuated the nephrin-β-arrestin2 interaction and abrogated the amplifying effect of high blood glucose on nephrin endocytosis. In C57BL/6 mice, hyperglycemia over 24 h caused a significant increase in urinary albumin excretion, supporting the concept of the rapid impact of hyperglycemia on glomerular permselectivity. In summary, we have provided a molecular model of hyperglycemia-induced nephrin endocytosis and subsequent proteinuria and highlighted PKCα and PICK1 as promising therapeutic targets for diabetic nephropathy.     

Bcl-2 allows effector and memory CD8+ T cells to tolerate higher expression of Bim

As acute infections resolve, most effector CD8(+) T cells die, whereas some persist and become memory T cells. Recent work showed that subsets of effector CD8(+) T cells, identified by reciprocal expression of killer cell lectin-like receptor G1 (KLRG1) and CD127, have different lifespans. Similar to previous reports, we found that effector CD8(+) T cells reported to have a longer lifespan (i.e., KLRG1(low)CD127(high)) have increased levels of Bcl-2 compared with their shorter-lived KLRG1(high)CD127(low) counterparts. Surprisingly, we found that these effector KLRG1(low)CD127(high) CD8(+) T cells also had increased levels of Bim compared with KLRG1(high)CD127(low) cells. Similar effects were observed in memory cells, in which CD8(+) central memory T cells expressed higher levels of Bim and Bcl-2 than did CD8(+) effector memory T cells. Using both pharmacologic and genetic approaches, we found that survival of both subsets of effector and memory CD8(+) T cells required Bcl-2 to combat the proapoptotic activity of Bim. Interestingly, inhibition or absence of Bcl-2 led to significantly decreased expression of Bim in surviving effector and memory T cells. In addition, manipulation of Bcl-2 levels by IL-7 or IL-15 also affected expression of Bim in effector CD8(+) T cells. Finally, we found that Bim levels were significantly increased in effector CD8(+) T cells lacking Bax and Bak. Together, these data indicate that cells having the highest levels of Bim are selected against during contraction of the response and that Bcl-2 determines the level of Bim that effector and memory T cells can tolerate.     

Generating social network data using partially described networks: an example informing avian influenza control in the British poultry industry

Background

The United Kingdom (UK) government has been recording the births, deaths, and movements of cattle for the last decade. Despite reservations about the accuracy of these data, they represent a large and valuable body of information about the demographics of the UK cattle herd and its contact structure. In this article, a range of demographic data about UK cattle, and particularly their movements, are presented, as well as yearly trends in the patterns of movements.

Results

A clear seasonal pattern is evident in the number of movements of cattle, as are the reductions in movement volume due to foot and mouth disease outbreaks in 2001 and 2007. The distribution of ages of cattle at their time of death is multimodal, and the impact of the over thirty months rule is marked. Most movements occur between agricultural holdings, markets, and slaughterhouses, and there is a non-random pattern to the types of holdings movements occur between. Most animals move only a short distance and a few times in their life. Most movements between any given pair of holdings only occurred once in the last 10 years, but about a third occurred between 2 and 10 times in that period. There is no clear trend to movement patterns in the UK since 2002.

Conclusions

Despite a substantial number of regulatory interventions during the last decade, movement patterns show no clear trend since 2002. The observed patterns in the repeatability of movements, the types of holdings involved in movements, the distances and frequencies of cattle movements, and the batch sizes involved give an insight into the structure of the UK cattle industry, and could act as the basis for a predictive model of livestock movements in the UK.     

Prevention of Parent to Child Transmission (PPTCT) Program Data in India: An Emerging Data Set for Appraising the HIV Epidemic

Background

Evidence based resource allocation and decentralized planning of an effective HIV/AIDS response requires reliable information on levels and trends of HIV at national and sub-national geographic levels. HIV sentinel surveillance data from antenatal clinics (HSS-ANC) has been an important data source to assess the HIV/AIDS epidemic in India, but has a number of limitations. We assess the value of Prevention of Parent to Child Transmission (PPTCT) programme data to appraise the HIV epidemic in India.

Methods/Findings

HIV data from PPTCT sites were compared to HSS-ANC and general population level surveys at various geographic levels in the states of Karnataka, Maharashtra and Andhra Pradesh. Chi-square tests were used to ascertain statistical significance. PPTCT HIV prevalence was significantly lower than HSS-ANC HIV prevalence (0.92% vs. 1.22% in Andhra Pradesh, 0.65% vs. 0.89% in Karnataka, 0.52% vs. 0.60% in Maharashtra, p<0.001 for all three states). In all three states, HIV prevalence from PPTCT centres that were part of the sentinel surveillance was comparable to HSS-ANC prevalence but significantly higher than PPTCT centres that were not part of the sentinel surveillance. HIV prevalence from PPTCT data was comparable to that from general population surveys. In all three states, significant declines in HIV prevalence between 2007 and 2010 were observed with the PPTCT data set. District level analyses of HIV trends and sub-district level analysis of HIV prevalence were possible using the PPTCT and not the HSS-ANC data sets.

Conclusion

HIV prevalence from PPTCT may be a better proxy for general population prevalence than HSS-ANC. PPTCT data allow for analysis of HIV prevalence and trends at smaller geographic units, which is important for decentralized planning of HIV/AIDS programming. With further improvements to the system, India could replace its HSS-ANC with PPTCT programme data for surveillance.