Inhibition of bfl-1/A1 by siRNA inhibits mycobacterial growth in THP-1 cells by enhancing phagosomal acidification

Virulent tubercle bacilli inhibit apoptosis to establish a safe environment within the host cells. Here, we report that NF-kappaB dependent antiapoptotic protein bfl-1/A1 plays an important role in this process. Both virulent and avirulent mycobacteria bearing THP-1 cells expressed considerable amount of bfl-1/A1 after 4 h of infection. However, after 48 h of infection, bfl-1/A1 expression was evident only in Mycobacterium tuberculosis H37Rv but not in M. tuberculosis H37Ra infected cells. When parallel experiments were performed with Human monocyte-derived macrophages (MDMs), differential expression of bfl-1/A1 mRNA was observed in case of M. tuberculosis H37Rv and M. tuberculosis H37Ra infection. siRNA mediated inhibition of bfl-1/A1 induced apoptosis in M. tuberculosis H37Rv infected THP-1 and MDMs. Reduction in intracellular mycobacterial growth was observed in bfl-1/A1 siRNA transfected, M. tuberculosis H37Rv infected THP-1 cells. Enhancement of phagosome-lysosome fusion was observed in bfl-1/A1 siRNA treated and M. tuberculosis H37Rv infected THP-1 cells. These results clearly indicated that differential expression of bfl-1/A1 in M. tuberculosis H37Rv and M. tuberculosis H37Ra infected THP-1 cells probably account for the difference in infection outcome.     

Malsoor Virus,a Novel Bat Phlebovirus,Is Closely Related to Severe Fever with Thrombocytopenia Syndrome Virus and Heartland Virus

During a survey in the year 2010, a novel phlebovirus was isolated from the Rousettus leschenaultii species of bats in western India. The virus was identified by electron microscopy from infected Vero E6 cells. Phylogenic analysis of the complete genome showed its close relation to severe fever with thrombocytopenia syndrome (SFTS) and Heartland viruses, which makes it imperative to further study its natural ecology and potential as a novel emerging zoonotic virus.     

Tryptophan force-feeding: Changes in the activities of acetylcholinesterase in various tissues of well-fed normal and adrenalectomized rats

The activity of acetylcholinesterase in the liver, heart, spleen, lungs and kidneys of well-fed normal and adrenalectomized rats was measured following a single tube-feeding of tryptophan. In well-fed normal rats, 30 min after tryptophan force-feeding, the enzyme activity in the heart and lungs was stimulated by 28 and 25% as compared to the water-fed control while in well-fed adrenalectomized rats acetylcholinesterase acticity in the heart, liver spleen and lungs was 40, 31, 22 and 15% increased, respectively over that of the corresponding control. In both groups of rats the enzyme activity in the kidney was unaffected by tryptophan. In the liver, spleen and heart of well-fed adrenalectomized rats the pattern of response for acetylcholinesterase to a tryptophan dose, over a period of 24-hr. was found to be biphasic. In well-fed adrenalectomized rats the tryptophan-mediated stimulation of acetylcholinesterase activity in the heart was found to be insensitive to actinomycin-D. The tryptophan-mediated stimulation of acetylcholinesterase activity in the heart of well-fed normal and adrenalectomized rats could not be related to the presence of an activator.     

Mixed-ligand tris chelated complexes of Mo(IV) and W(IV): A comparative study

Two hitherto unknown mixed-ligand tris chelated complexes containing 2-aminothiophenolate, [Et₄N]₂[M^IV(NH-(C₆H₄)-S)(mnt)₂] (M = Mo, 1a; W, 2a) and two mixed-ligand tris chelate complex containing N,N-diethyldithiocarbamate, [Et₄N]₂[M^IV(Et₂NS₂)(mnt)₂] (M = Mo, 1b; W, 2b) have been synthesized and characterized structurally. Although these complexes are supposed to be quite similar to the well-known symmetric tris chelate complexes of maleonitriledithiolate (mnt), [Et₄N]₂[M^IV(mnt)₃] (M = Mo, 1c; W, 2c), but display both trigonal prismatic and distorted trigonal prismatic geometry in their crystal structure indicating the possibility of an equilibrium between these two structural possibilities in solution. Unlike extreme stability of 1b, 2b, 1c and 2c, both 1a and 2a are highly unstable in solution. In contrast to one reversible reduction in case of 1b and 2b, 1a and 2a exhibited no possible reduction up to −1.2 V and two sequential oxidation steps which have been further investigated with EPR study. Differences in stability and electrochemical behavior of 1a, 1b, 2a and 2b have been correlated with theoretical calculations at DFT level in comparison with long known 1c and 2c.     

Gastric mucosal tyrosine kinase activity during aging and its relationship to cell proliferation in rats

The relationship between tyrosine kinase activity and cellular proliferative activity was investigated in the gastric mucosa. For the purpose of comparison, the liver and the pancreas were also included. Groups of 2-, 14- and 22-month-old male Fischer-344 rats were used. Tyrosine kinase activity was determined in the membrane fraction (30,000 x g pellet) utilizing a synthetic polymer, Glu-Tyr (4:1), as substrate. Cellular proliferative activity was assessed by measuring ornithine decarboxylase in the 20,000 x g supernatant. In all age groups, gastric mucosal tyrosine kinase activity was found to be 10-20-fold higher than in the liver or pancreas. In addition, gastric mucosal tyrosine kinase activity in 22-month-old rats was 35-70% higher than in their 2- and 14-month-old counterparts. Gastric mucosal ornithine decarboxylase activity also followed essentially the same pattern as that of tyrosine kinase in that the highest activity was observed in 22-month-old rats. Increased gastric mucosal proliferative activity in 22-month-old rats was also associated with increased tyrosine-phosphorylation of a mucosal membrane protein with an apparent Mr of 53,000. An opposite phenomenon occurred in the pancreas whose proliferative activity was found to be the lowest. It is concluded that the age-associated changes in gastric mucosal proliferative activity are accompanied by parallel alterations in tyrosine kinase activity. Tyrosine-phosphorylation of a 53 kDa membrane protein may play a role in the regulation of cell proliferation.     

Effect of Pseudomonas aeruginosa exotoxin-A on the synthesis and secretion of proteins in isolated rat pancreatic acini

Exposure of isolated rat dispersed pancreatic acini to increasing concentrations (10 to 1000 ng/ml) of purified exotoxin-A from Pseudomonas aeruginosa resulted in a progressive inhibition of 3H-leucine incorporation into "cellular" (those remaining in the cells) and "secretory" (those released into the medium) proteins. With each concentration of exotoxin-A, magnitude of reduction was found to be greater for the "secretory" proteins than that observed for the "cellular" proteins. Thus, in the presence of 250 ng/ml of exotoxin-A, a dose that produced maximal inhibition in protein synthesis, 3H-leucine incorporation into "cellular" and "secretory" proteins was found to be decreased by about 19 and 50%, respectively, when compared with the corresponding basal controls. Release of trypsinogen, chymotrypsinogen and amylase from the isolated pancreatic acini was also inhibited by high doses of exotoxin-A. However, whereas the exotoxin concentration of 1000 ng/ml, caused a near complete inhibition of chymotrypsinogen release, trypsinogen and amylase secretion were decreased by 40 and 50%, respectively. It is concluded that in isolated pancreatic acini, exotoxin-A inhibits the synthesis and secretion of proteins.     

Immobilization of whole cells ofStreptomyces kanamyceticus containing glucose isomerase by a combination of heat treatment in the presence of minerals and entrapment in calcium alginate gels

A method of immobilization of whole cells ofStreptomyces kanamyceticus containing glucose isomerase was devised, based on techniques of heat fixation in the presence of minerals and, entrapment in calcium alginate gels. The optimum activity of the enzyme was obtained when the cells were heat-fixed at 60°C for 10 min in the presence of 50 mmol/L MgSO₄·7H₂O and 5 mmol/L CoCl₂·6H₂O and then cast into calcium alginate beads using 2% sodium alginate.     

Quorum sensing: a quantum perspective

Quorum sensing is the efficient mode of communication in the bacterial world. After a lot of advancements in the classical theory of quorum sensing few basic questions of quorum sensing still remain unanswered. The sufficient progresses in quantum biology demands to explain these questions from the quantum perspective as non trivial quantum effects already have manifested in various biological processes like photosynthesis, magneto-reception etc. Therefore, it’s the time to review the bacterial communications from the quantum view point. In this article we carefully accumulate the latest results and arguments to strengthen quantum biology through the addition of quorum sensing mechanism in the light of quantum mechanics.