Drug-membrane interactions studied in phospholipid monolayers adsorbed on nonporous alkylated microspheres

Characterization of interactions with phospholipids is an integral part of the in vitro profiling of drug candidates because of the roles the interactions play in tissue accumulation and passive diffusion. Currently used test systems may inadequately emulate the bilayer core solvation properties (immobilized artificial membranes [IAM]), suffer from potentially slow transport of some chemicals (liposomes in free or immobilized forms), and require a tedious separation (if used for free liposomes). Here the authors introduce a well-defined system overcoming these drawbacks: nonporous octadecylsilica particles coated with a self-assembled phospholipid monolayer. The coating mimics the structure of the headgroup region, as well as the thickness and properties of the hydrocarbon core, more closely than IAM. The monolayer has a similar transition temperature pattern as the corresponding bilayer. The particles can be separated by filtration or a mild centrifugation. The partitioning equilibria of 81 tested chemicals were dissected into the headgroup and core contributions, the latter using the alkane/water partition coefficients. The deconvolution allowed a successful prediction of the bilayer/water partition coefficients with the standard deviation of 0.26 log units. The plate-friendly assay is suitable for high-throughput profiling of drug candidates without sacrificing the quality of analysis or details of the drug-phospholipid interactions.     

Inhibition of Porcine Pancreatic Amylase Activity by Sulfamethoxazole: Structural and Functional Aspect

Combating Type-2 diabetes mellitus is a pivotal challenge in front of the present world. Several lines of therapy are in practice for resisting this deadly disease which often culminates with cardiovascular complexities, neuropathy and retinopathy. Among various therapies, administration of alpha glucosidase inhibitors is common and widely practiced. Sulfonylurea category of anti diabetic drug often suffers from cross reactivity with sulfamethoxazole (SMX), a common drug in use to treat a handful of microbial infections. However the specific cellular target generating postprandial hypoglycemia on SMX administration is till date unraveled. The present work has been initiated to elucidate the effects of a group of sulfonamide drugs inclusive of SMX for their amylase inhibitory role. SMX inhibits porcine pancreatic amylase (PPA) in a noncompetitive mode with an average IC₅₀ value 0.94 mM respectively. Interaction of SMX with PPA is manifested with gradual quenching of tryptophan fluorescence with concomitant shift in lambda max value (λ_max). Binding is governed by entropy driven factor (24.8 cal mol^?1 K^?1) with unfavorable contribution from enthalpy change. SMX interferes with the activity of acarbose in a synergistic mode to reduce the effective dose of acarbose as evident from the in vitro PPA inhibition study. In summary, loss of PPA activity in presence of SMX is indicative of structural changes of PPA which is further augmented in the presence of acarbose as explained in the schematic model and docking study.     

Co-chaperone CHIP Stabilizes Aggregate-prone Malin, a Ubiquitin Ligase Mutated in Lafora Disease

Lafora disease (LD) is an autosomal recessive neurodegenerative disorder caused by mutation in either the dual specificity phosphatase laforin or ubiquitin ligase malin. A pathological hallmark of LD is the accumulation of cytoplasmic polyglucosan inclusions commonly known as Lafora bodies in both neuronal and non-neuronal tissues. How mutations in these two proteins cause disease pathogenesis is not well understood. Malin interacts with laforin and recruits to aggresomes upon proteasome inhibition and was shown to degrade misfolded proteins. Here we report that malin is spontaneously misfolded and tends to be aggregated, degraded by proteasomes, and forms not only aggresomes but also other cytoplasmic and nuclear aggregates in all transfected cells upon proteasomal inhibition. Malin also interacts with Hsp70. Several disease-causing mutants of malin are comparatively more unstable than wild type and form aggregates in most transfected cells even without the inhibition of proteasome function. These cytoplasmic and nuclear aggregates are immunoreactive to ubiquitin and 20 S proteasome. Interestingly, progressive proteasomal dysfunction and cell death is also most frequently observed in the mutant malin-overexpressed cells compared with the wild-type counterpart. Finally, we demonstrate that the co-chaperone carboxyl terminus of the Hsc70-interacting protein (CHIP) stabilizes malin by modulating the activity of Hsp70. All together, our results suggest that malin is unstable, and the aggregate-prone protein and co-chaperone CHIP can modulate its stability.     

Ecofriendly Heavy Metal Stabilization: Microbial Induced Mineral Precipitation (MIMP) and Biomineralization for Heavy Metals within the Contaminated Soil by Indigenous Bacteria

Heavy metals (HMs) pollution is a serious problem, worldwide. The present study focuses on HMs removal (HMs mobility restricted within soil) by microbial induced mineral precipitation (MIMP) using indigenous isolates. Indigenous isolates were identified as Bacillus subtilis C(225)(MK334652), Oceanobacillus indicireducens 5(225)(MK334653), and Bacillus pumilus 7(225)(MK334654) by 16S-rRNA from HMs polluted industrial-soil (soil-225) that is used for bioremediation. The studied soil contained high level (mg/kg) of Cr(307.41?±?1.02), Cu(576.35?±?1.02), and Zn(708.81?±?1.50) as per Taiwan permissible limit (TPL) and/or Canadian Soil Quality Guidelines (CSQG). Minimum inhibitory concentration (MIC) of Bacillus species were higher compare to Oceanobacillus. Bioavailable-fraction (F₁) of HMs (Cr/Cu/Zn) in untreated 225-soil was noticed to be higher compared to F₂–F₅ fraction. Bacillus subtilis C(225) are more efficient for HMs-mineralization, compared to other isolates where Cr/Cu/Zn immobilized within soil, transforming from bioavailable-fraction (F₁) (high-mobility) (60–90% reduction) to residual-fraction F₅ (low-mobility) (50–80% increment). Organic-bound-fraction (F₄) (medium-mobility) of Cr increased (42.66?±?2.1%), compared to Cu/Zn, by Bacillus subtilis C(225). Urease (40.8%) and dehydrogenase (8.3%) activity increased in bio-remediated soil, compared to control. MIMP of HMs by ingenious bacteria reflects the transformation-pathway from F₁ to F₅ of HMs to fix strongly within soils with inadequate mobility. Thus, MIMP by indigenous microbe can be applicable for HMs stabilization/removal in contaminated soil for ecofriendly environmental cleanup.     

Analysis of DevR regulated genes in Mycobacterium tuberculosis

The DevRS two component system of Mycobacterium tuberculosis is responsible for its dormancy in host and becomes operative under hypoxic condition. It is experimentally known that phosphorylated DevR controls the expression of several downstream genes in a complex manner. In the present work we propose a theoretical model to show role of binding sites in DevR mediated gene expression. Individual and collective role of binding sites in regulating DevR mediated gene expression has been shown via modeling. Objective of the present work is twofold. First, to describe qualitatively the temporal dynamics of wild type genes and their known mutants. Based on these results we propose that DevR controlled gene expression follows a specific pattern which is efficient in describing other DevR mediated gene expression. Second, to analyze behavior of the system from information theoretical point of view. Using the tools of information theory we have calculated molecular efficiency of the system and have shown that it is close to the maximum limit of isothermal efficiency.     

Prevalence of Enteropathogenic <Emphasis Type="Italic">Escherichia coli</Emphasis> Isolated from <Emphasis Type="Italic">Chhana</Emphasis> Based Indian Sweets in Relation to Public Health

Chhana based milk products viz. rossogolla, kanchagolla, narampak sandesh and karapak sandesh are very popular in eastern part of India and gaining popularity in other parts of the country. A wide variation in manufacture method, microbial quality and shelf-life of these traditional milk products were observed by previous research. The aim of the present study was to determine the prevalence of contamination of chhana based milk products available in Kolkata city with Enteropathogenic Escherichia coli (EPEC) serogroups. Random samples of different chhana based milk products were collected from different parts of Kolkata city in aseptic condition, cultured in selective media and examined for biochemical tests. Among 240 samples, E. coli was isolated from 67 (27.91%) of them. Potential EPEC was present in 52 samples (21.66%) and 55 of the isolates were EPEC. Eleven serogroups were identified viz. O26, O55, O111, O119, O114, O125, O142, O86, O126, O127, O128. Among all these serogroups, O55 (23.66%) was the most prevalent. Though recent studies on virulence factors indicate that not all strains serologically classified as EPEC are able to attaching/effacing lesion, it is believed that the isolation of EPEC serogroups from chhana based milk products represent a potential risk for public health particularly children, as well as an indicative of the presence of other enteropathogens. Considering the public health importance of sweetmeat consumers, the product should be prepared hygienically reducing the microbial load present in it. The result indicates that strict preventive measures should be adopted to ensure contamination free sweetmeats for the safety of the consumers.     

Lumbar muscle electromyographic dynamic topography during flexion-extension

The objective of this study is to introduce dynamic topography of surface electromyography (SEMG) to visualize lumbar muscle myoelectric activity and provides a new view to analyze muscle activity in vivo. A total of 20 healthy male subjects and 15 males LBP were enrolled. An electrode-array was applied to the lumbar region to collect SEMG. The root mean square (RMS) value was calculated for each channel, and then a 160×120 matrix was constructed using a linear cubic spline interpolation of each scan to create a 2-D color topographic image. Along a definite interval of action, a series of RMS topography matrices was concatenated as a function of position and time, to form a dynamic topographical video of lumbar muscle activity. Relative area (RA), relative width (RW), relative height (RH) and Width-to-Height Ratio (W/H) were chosen as the four quantitative parameters in measuring topographic features. Normal RMS dynamic topography was found to have a consistent, symmetric pattern with a high intensity area in the paraspinal area. LBP patients had a different RMS dynamic topography, with an asymmetric, broad, or disorganized distribution. Quantitative SEMG features were found significantly different between normal control and LBP. After physiotherapy rehabilitation, the dynamic topography images of LBP tended towards the normal pattern.There are obvious differences in lumbar muscle coordination between healthy subjects and LBP patients. The dynamic topography allows the continuous visualization of the distribution of surface EMG signals and the coordination of muscular contractions.     

Income and nutritional status of the fishing community residing in coastal bay of Bengal: a case study

This is part of a project on the disadvantaged, marginalized, vulnerable/weaker section of the population and their survival strategy. The paper presents the results of a survey carried out during 2006-07 with the objective of throwing light on the life and living conditions of an economically weaker community such as 'fishing community' residing in the coastal area of Bay of Bengal in West Bengal and Orissa, India, in the context of global scenario. Various scientists have conducted quite a large number of studies to ascertain the income and nutritional status of people in rural India. Very few attempts, however, have been made to investigate in detail regarding the living standards of some specific communities, which are very often referred to, as the 'weaker section' of the people. The people belonging to fishing community are, by and large, not only economically weak in terms of earning and availability of work, the majority of them are not able to procure the minimum nourishment. The present study shows that some notable elements of living conditions such as food, shelter, health etc. matters much more than the conventional income or calorie deficiency. Commonly, the social scientists equate poverty with income or calorie deficiency which may not be the case as is evident from this study. We have hinted some measures to be undertaken to ameliorate the sufferings of the fishing community.