Somatic embryogenesis,regeneration and <Emphasis Type="Italic">in vitro</Emphasis> production of glycyrrhizic acid from root cultures of <Emphasis Type="Italic">Taverniera cuneifolia</Emphasis> (Roth) Arn.

Taverniera cuneifolia (Roth) Arn. or Indian licorice is considered to be a substitute for Glycyrrhiza glabra L. owing to an equivalent content of glycyrrhizic acid (GA). GA recognized as the main active ingredient of T. cuneifolia, GA imparts several medicinal properties to these plants. However, research on this plant is scanty with no published record on tissue culture studies. Present study demonstrates a method for (1) induction and successful development of somatic embryos from the root culture, (2) regeneration of plants, and (3) GA production by root cultures of T. cuneifolia. Shoot initiation frequency of cultured roots ranged from 52.57% to 97.71%. Plant regeneration frequency (germination) from somatic embryos was 88.66% in 1/4-strength Murashige and Skoog (MS) medium supplemented with 2% sucrose, as against 68% in half 1/2-strength MS containing 2% sucrose. Glycyrrhizic acid of 1.32 mg/gm of dry weight was obtained in full-strength MS medium supplemented with 3% sucrose, through high-performance thin layer chromatography analysis with standard GA in root cultures. The present study provides an efficient method for the mass production of plants from a single mother plant as well as the potential root culture system to study the GA production pathways in T. cuneifolia.     

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.     

SUMOylation of Pancreatic Glucokinase Regulates Its Cellular Stability and Activity

Glucokinase is the predominant hexokinase expressed in hepatocytes and pancreatic β-cells, with a pivotal role in regulating glucose-stimulated insulin secretion, illustrated by glucokinase gene mutations causing monogenic diabetes and congenital hyperinsulinemic hypoglycemia. A complex tissue-specific network of mechanisms regulates this enzyme, and a major unanswered question in glucokinase biology is how post-translational modifications control the function of the enzyme. Here, we show that the pancreatic isoform of human glucokinase is SUMOylated in vitro, using recombinant enzymes, and in insulin-secreting model cells. Three N-terminal lysines unique for the pancreatic isoform (Lys-12/Lys-13 and/or Lys-15) may represent one SUMOylation site, with an additional site (Lys-346) common for the pancreatic and the liver isoform. SUMO-1 and E2 overexpression stabilized preferentially the wild-type human pancreatic enzyme in MIN6 β-cells, and SUMOylation increased the catalytic activity of recombinant human glucokinase in vitro and also of glucokinase in target cells. Small ubiquitin-like modifier conjugation represents a novel form of post-translational modification of the enzyme, and it may have an important regulatory function in pancreatic β-cells.     

Caffeine affects adventitious rooting and causes biochemical changes in the hypocotyl cuttings of mung bean (<Emphasis Type="Italic">Phaseolus aureus</Emphasis> Roxb.)

Caffeine (1,3,7-trimethylxanthine), a purine alkaloid found naturally in over 100 plant species, has recently been viewed as a safe chemical for management of pests including molluscs, slugs, snails, bacteria, and as a bird deterrent. It possesses phytotoxicity against plant species, yet the mechanism of action is lacking. A study was conducted to determine the effect of caffeine on the rooting of hypocotyl cuttings of mung bean (Phaseolus aureus) and the associated biochemical changes. At lower concentrations (<1,000 μM) of caffeine, though rooting potential was not affected, yet there was a significant decrease in the number of roots and root length. At 1,000 μM caffeine, there was a 68% decrease in the number of roots/primordia per cutting, whereas root length decreased by over 80%. However, no root formation occurred at 2,000 μM caffeine. Further investigations into the biochemical processes linked to root formation revealed that caffeine significantly affects protein content, activities of proteases, polyphenol oxidases (PPO) and total endogenous phenolic (EP) content, in the mung bean hypocotyls. A decrease in rooting potential was associated with a drastic reduction in protein content in the lower rooted portion, whereas the specific activity of proteases increased indicating that caffeine affects the protein metabolism. Activity of PPO decreased in response to caffeine, whereas EP content increased significantly indicating its non-utilization and thus less or no root formation. Respiratory ability of rooted tissue, as determined through TTC (2,3,5-triphenyl tetrazolium chloride) reduction, was impaired in response to caffeine indicating an adverse effect on the energy metabolism. The study concludes that caffeine interferes with the root development by impairing protein metabolism, affecting activity of PPO (and thus lignification), and EP content, which are the crucial steps for root formation.