Purification and properties of diaminopimelate decarboxylase ofMicrococcus glutamicus

Diaminopimelate decarboxylase (EC 4.1.1.20) ofMicrococcus glutamicus ATCC 13059 was purified to homogeneity. The enzyme had an apparent molecular weight of 191,000 as determined by gel filtration on Sephadex G-200. At protein concentrations of 20 and 10 μg per ml and in the absence of pyridoxal-5′-phosphate, it dissociated into a species of molecular weight 94,000. The polypeptide chain molecular weight as determined by sodium dodecyl sulphate Polyacrylamide gel electrophoresis was 100,000. TheK _m formeso diaminopimelate was 0.5 mM and that for pyridoxal-5′-phosphate was 0.6 μI. Sulphydryl groups and pyridoxal-5′-phosphate were essential for activity and stability. The enzyme was inhibited significantly by L-lysine and DL-aspartic β-semialdehyde.     

Excretion of lysine byMicrococcus glutamicus

Analysis of intracellular and extracellular lysine concentration during lysine fermentation byMicrococcus glutamicus AEC RN-13-6/1 indicated that lysine excretion occurs against a concentration gradient towards the end of the fermentation period. The capacity to excrete lysine against a concentration gradient may be a factor contributing to the high yield of lysine.     

Comparison of innate immune activation after prolonged feeding of milk fermented with three species of Lactobacilli

The present investigation aimed at identifying the abilities of three different species of probiotic lactobacilli to modulate cellular immune responses in mouse neutrophils and macrophages in vivo over a study period of 60 days. Neutrophil respiratory burst enzymes (cytochrome c reductase and MPO) showed remarkable increased activity (P ≤ 0.01) after consumption of milks fermented by different species of probiotics over 30 and 60 days of feeding trials. Enzyme activities (β‐galactosidase and β‐glucuronidase) and nitric oxide production also increased considerably (P ≤ 0.01) in macrophages, both in peritoneal fluid and in enriched cell cultures. The effects of enhanced enzyme activities were corroborated by simultaneous increases in the phagocytic activities of neutrophils and macrophages. The increases in cellular functions were invariably maximal during the first 30 days of study and were maintained, but did not increase, over the next 30 days. Further, Lactobacillus helveticus‐fed groups were most effective at modulating neutrophil functions whereas Lactobacillus paracasei‐fed groups were more potent at enhancing macrophage functions. Together, our results indicate that probiotics have strain specific effects on stimulating cellular functions while not causing excessive stimulation of the immune system over longer feeding periods, thereby resulting in maximum and stable health benefits.     

Consequences of adaptation to larval crowding on sexual and fecundity selection in Drosophila melanogaster

Sexual selection is a major force influencing the evolution of sexually reproducing species. Environmental factors such as larval density can manipulate adult condition and influence the direction and strength of sexual selection. While most studies on the influence of larval crowding on sexual selection are either correlational or single-generation manipulations, it is unclear how evolution under chronic larval crowding affects sexual selection. To answer this, we measured the strength of sexual selection on male and female Drosophila melanogaster that had evolved under chronic larval crowding for over 250 generations in the laboratory, along with their controls which had never experienced crowding, in a common garden high-density environment. We measured selection coefficients on male mating success and sex-specific reproductive success, as separate estimates allowed dissection of sex-specific effects. We show that experimental evolution under chronic larval crowding decreases the strength of sexual and fecundity selection in males but not in females, relative to populations experiencing crowding for the first time. The effect of larval crowding in reducing reproductive success is almost twice in females than in males. Our study highlights the importance of studying how evolution in a novel, stressful environment can shape adult fitness in organisms.     

Facile synthesis of fluorescent polysaccharides: Cytosine grafted agarose and κ-carrageenan

New fluorescent polymeric materials were synthesized by grafting the nucleobase cytosine on to the backbone of agarose and κ-carrageenan, employing a rapid water based method under microwave irradiation using potassium persulphate (KPS) as an initiator. The emission spectrum of the modified agarose and κ-carrageenan recorded in aqueous solution (5 × 10⁻⁵ M) exhibited emission maxima (λ_em,max) at 348 nm by excitation at 266 nm. The emission intensity was enhanced by ca. 104% and 60% compared to that of pure cytosine solution of the same concentration. When the concentration of the pure cytosine solution is made equivalent to the concentration of the cytosine molar component (3.09 × 10⁻⁵) and (3.5 × 10⁻⁵) present in 5 × 10⁻⁵ M solution of modified agarose and κ-carrageenan, respectively, then ca. 143% and 81% enhancement in emission intensity was observed. The remarkable fluorescent activity of the agarose-cytosine derivative may have potential uses as sensor in various applications.     

Milk fermented with probiotic strains Lactobacillus rhamnosus MTCC: 5957 and Lactobacillus rhamnosus MTCC: 5897 ameliorates the diet-induced hypercholesterolemia in rats

The current study was intended to investigate the cholesterol-lowering potential of the two Lactobacillus rhamnosus probiotic strains, LR 5957 and LR 5897, isolated from ‘dahi’. Cholesterol-lowering ability of both strains was determined in in vitro conditions. For in vivo investigations, the Wistar rats were randomly assigned into five groups and treated with different diets: standard diet (SD), high-cholesterol diet (HCD), HCD with Milk, HCD with LR 5957–fermented milk, and HCD with LR 5897–fermented milk. After 3 months of feeding, different parameters of hypercholesterolemia were measured in blood, feces, liver, and kidney. Both the strains, LR 5957 and LR 5897, showed the ability to grow in the presence of cholesterol and eliminate the cholesterol under in vitro conditions. In vivo results indicate that consumption of probiotic-fermented milk has significantly reduced the HCD-induced body weight, hyperlipidemia, and hepatic lipids (total cholesterol and triacylglycerol). Further, increased cholesterol excretion in feces was also observed in probiotic-fed groups. The studied fermented milk also helped to maintain healthy liver and kidney by increasing the antioxidant activities and decreasing the lipid peroxidation. Consumption of probiotic-fermented milk also found to decrease the mRNA expression of the inflammatory markers TNF-α and IL-6 in the liver. Overall, our results indicate that the L. rhamnosus strains, LR 5957 and LR 5897, are two potential probiotic strains that can ameliorate the diet-induced hypercholesterolemia.     

Combinatorial Approach Through In Vitro Regeneration and Phytochemical Profiling of Ceropegia media (Huber) Ans.: A Potential Way Forward in the Conservation of an Endangered Medicinal Plant from the Western Ghats in India

Journal of Plant Growth Regulation - Ceropegia media is an endemic and endangered plant as its propagation through seeds is unreliable due to low germination, slow growth and seedling decay under...