Modeling in vitro cholesterol reduction in relation to growth of probiotic Lactobacillus casei

Lactobacillus casei LA‐1 isolated from a nondairy fermented source was evaluated for its in vitro ability to reduce cholesterol. The bacterium tested positive for bile salt deconjugation in relation to cholesterol removal. Tested growth‐associated physiological variables such as pH, temperature and inoculum size were all found to have significant effects on in vitro cholesterol reduction and biomass production (both P < 0.005). Furthermore, a central composite design was used to evaluate the effects of significant variables and their interactions. A linear regression model was developed for in vitro cholesterol reduction as a function of growth‐associated variables. Maximum cholesterol reduction achieved was 45% whereas maximum biomass yield of 2.34 optical density was observed at the central point. Our study possibly indicates that the growth of L. casei LA‐1 depends on its cholesterol removing ability.     

Identification of mycobacterial lectins from genomic data

Sixty‐four sequences containing lectin domains with homologs of known three‐dimensional structure were identified through a search of mycobacterial genomes. They appear to belong to the β‐prism II, the C‐type, the Microcystis virdis (MV), and the β‐trefoil lectin folds. The first three always occur in conjunction with the LysM, the PI‐PLC, and the β‐grasp domains, respectively while mycobacterial β‐trefoil lectins are unaccompanied by any other domain. Thirty heparin binding hemagglutinins (HBHA), already annotated, have also been included in the study although they have no homologs of known three‐dimensional structure. The biological role of HBHA has been well characterized. A comparison between the sequences of the lectin from pathogenic and nonpathogenic mycobacteria provides insights into the carbohydrate binding region of the molecule, but the structure of the molecule is yet to be determined. A reasonable picture of the structural features of other mycobacterial proteins containing one or the other of the four lectin domains can be gleaned through the examination of homologs proteins, although the structure of none of them is available. Their biological role is also yet to be elucidated. The work presented here is among the first steps towards exploring the almost unexplored area of the structural biology of mycobacterial lectins. Proteins 2013. © 2012 Wiley Periodicals, Inc.     

ACC Deaminase-Containing Bacillus subtilis Reduces Stress Ethylene-Induced Damage and Improves Mycorrhizal Colonization and Rhizobial Nodulation in Trigonella foenum-graecum Under Drought Stress

This study was aimed at protecting Trigonella plants by reducing stress ethylene levels through ACC (1-aminocyclopropane-1-carboxylic acid) deaminase-containing Bacillus subtilis (LDR2) and promoting plant growth through improved colonization of beneficial microbes like Ensifer meliloti (Em) and Rhizophagus irregularis (Ri) under drought stress. A plant growth-promoting rhizobacterium strain possessing high levels of ACC deaminase characterized as B. subtilis was selected. Application of this strain considerably protected Trigonella plants under severe drought stress conditions; this protection was correlated with reduced levels of ACC (responsible for generation of stress ethylene). The experiment consisted of eight inoculation treatments with different combinations of ACC deaminase-containing rhizobacteria LDR2, Ri, and Em under three water regimes. The tripartite combination of LDR2 + Ri + Em acted synergistically to induce protective mechanisms against decreased soil water availability in Trigonella plants and improved plant weight by 56 % with lower ACC concentration (39 % less than stressed noninoculated plants) under severe drought conditions. Drought-induced changes in biochemical markers like reduced chlorophyll concentration, increased proline content, and higher lipid peroxidation were monitored and clearly indicated the protective effects of LDR2 under drought stress. Under drought conditions, apart from alleviating ethylene-induced damage, LDR2 enhanced nodulation and arbuscular mycorrhizal fungi colonization in the plants resulting in improved nutrient uptake and plant growth.     

Notch Pathway Activation Contributes to Inhibition of C2C12 Myoblast Differentiation by Ethanol

The loss of muscle mass in alcoholic myopathy may reflect alcohol inhibition of myogenic cell differentiation into myotubes. Here, using a high content imaging system we show that ethanol inhibits C2C12 myoblast differentiation by reducing myogenic fusion, creating smaller and less complex myotubes compared with controls. Ethanol administration during C2C12 differentiation reduced MyoD and myogenin expression, and microarray analysis identified ethanol activation of the Notch signaling pathway target genes Hes1 and Hey1. A reporter plasmid regulated by the Hes1 proximal promoter was activated by alcohol treatment in C2C12 cells. Treatment of differentiating C2C12 cells with a gamma secretase inhibitor (GSI) abrogated induction of Hes1. On a morphological level GSI treatment completely rescued myogenic fusion defects and partially restored other myotube parameters in response to alcohol. We conclude that alcohol inhibits C2C12 myoblast differentiation and the inhibition of myogenic fusion is mediated by Notch pathway activation.     

Study of Surface Enhanced Raman Scattering of Single Molecule Adsorbed on the Surface of Metal Nanogeometries: Electrostatic Approach

Plasmonics - In this paper, we have studied the surface enhanced raman scattering (SERS) from a molecule adsorbed on coated and non-coated spherical shape metallic nanoparticles. We have accounted...     

Numerical Simulation of Broadband Scattering by Coated and Noncoated Metal Nanostructures Using Discrete Dipole Approximation Method

We suggest numerical method to study the optical response of metal nanostructures. The analysis of optical properties such as scattering and absorption by coated and noncoated nanogeometry has been done using discrete dipole approximation (DDA) method. The core-shell nanogeometry supports surface plasmon resonances, which are highly tunable from 400 to 1100 nm. The tunability of surface plasmon resonance (SPR) highly depends on the structural anisotropy and chosen core-shell material. Further, we have observed that aspect ratio is one of the key parameter to decide the nature and position of the plasmonic peaks and magnitude of optical cross section. We have also shown that coated nanospheroid is a more appropriate geometry as compared to coated nanosphere and noncoated nanospheroid in terms of wide tunability of surface plasmon resonance. The wide tunability in SPR is observed for the effective radii 90 nm core-shell (Au@SiO₂) nanospheroid with aspect ratio 0.1.     

Hyper-Variability in Circulating Insulin,High Fat Feeding Outcomes,and Effects of Reducing Ins2 Dosage in Male Ins1-Null Mice in a Specific Pathogen-Free Facility

Insulin is an essential hormone with key roles in energy homeostasis and body composition. Mice and rats, unlike other mammals, have two insulin genes: the rodent-specific Ins1 gene and the ancestral Ins2 gene. The relationships between insulin gene dosage and obesity has previously been explored in male and female Ins2^-/- mice with full or reduced Ins1 dosage, as well as in female Ins1^-/- mice with full or partial Ins2 dosage. We report herein unexpected hyper-variability in Ins1-null male mice, with respect to their circulating insulin levels and to the physiological effects of modulating Ins2 gene dosage. Two large cohorts of Ins1^-/-:Ins2^+/- mice and their Ins1^-/-:Ins2^+/+ littermates were fed chow diet or high fat diet (HFD) from weaning, and housed in specific pathogen-free conditions. Cohort A and cohort B were studied one year apart. Contrary to female mice from the same litters, inactivating one Ins2 allele on the complete Ins1-null background did not consistently cause a reduction of circulating insulin in male mice, on either diet. In cohort A, all HFD-fed males showed an equivalent degree of insulin hypersecretion and weight gain, regardless of Ins2 dosage. In cohort B the effects of HFD appeared generally diminished, and cohort B Ins1^-/-:Ins2^+/- males showed decreased insulin levels and body mass compared to Ins1^-/-:Ins2^+/+ littermates, on both diets. Although experimental conditions were consistent between cohorts, we found that HFD-fed Ins1^-/-:Ins2^+/- mice with lower insulin levels had increased corticosterone. Collectively, these observations highlight the phenotypic characteristics that change in association with differences in circulating insulin and Ins2 gene dosage, particularly in male mice.