1,25 Dihydroxyvitamin D3-dependent inhibition of growth or killing of Mycobacterium avium complex in human macrophages is mediated by TNF and GM-CSF

Vitamin D3 (D3) has been shown to activate several macrophage functions. To determine whether D3 could activate macrophages to kill or inhibit intracellular growth of Mycobacterium avium complex (MAC), human monocyte-derived macrophages were treated with D3 (10(-7), 10(-8), and 10(-9) M) 24 hr before or for 48 hr after MAC infection. All three concentrations were associated with inhibition of growth or killing of MAC in a dose-dependent fashion (28 +/- 4% and 22 +/- 3% of killing and inhibition of growth, respectively, at pharmacological concentrations) when added to the monolayer before injection or 60.4 +/- 6%, 50.4 +/- 3%, and 41.4 +/- 6%, respectively, when added to the monolayers after infection. We found that D3-treated macrophages produced increased concentrations of tumor necrosis factor (TNF) and granulocyte-monocyte colony stimulating factor (GM-CSF). Subsequently, macrophages were activated by D3 in the presence of anti-TNF or anti-GM-CSF antibody: At 10(-9) M of D3 there was no inhibition of D3-dependent macrophage activation by anti-TNF antibody, whereas anti-GM-CSF antibody was associated with 100% inhibition. At 10(-8) M of D3, anti-TNF antibody inhibited 35 +/- 6% of killing, and anti-GM-CSF antibody was associated with 100% inhibition. At 10(-7) M of D3, anti-TNF antibody inhibited 58 +/- 4% and anti-GM-CSF antibody 89 +/- 3% of killing. D3 treatment is associated with anti-MAC activity in human macrophages, and this activity appears to be mediated by both TNF and GM-CSF.     

A purine permease in Candida glabrata

Abstract Competition experiments revealed that adenine and guanine were transported by a purine permease in both Candida glabrata 4 and a C. glabrata 4 cytosine permease negative mutant. The C. glabrata 4 cytosine permease negative mutant was isolated using 5-fluorocytosine selection. This mutant no longer transported cytosine, but transported adenine and guanine. A transport system for hypoxanthine was not detected. Hence, in addition to the cytosine permease, a purine permease exists in C. glabrata . This differs from the purine cytosine permeases in Saccharomyces cereuisiae and Candida albicans which transport adenine, cytosine, guanine and hypoxanthine.     

A Wandering Mind Does Not Stray Far from Home: The Value of Metacognition in Distant Search

When faced with a problem, how do individuals search for potential solutions? In this article, we explore the cognitive processes that lead to local search (i.e., identifying options closest to existing solutions) and distant search (i.e., identifying options of a qualitatively different nature than existing solutions). We suggest that mind wandering is likely to lead to local search because it operates by spreading activation from initial ideas to closely associated ideas. This reduces the likelihood of accessing a qualitatively different solution. However, instead of getting lost in thought, individuals can also step back and monitor their thoughts from a detached perspective. Such mindful metacognition, we suggest, is likely to lead to distant search because it redistributes activation away from initial ideas to other, less strongly associated, ideas. This hypothesis was confirmed across two studies. Thus, getting lost in thoughts is helpful when one is on the right track and needs only a local search whereas stepping back from thoughts is helpful when one needs distant search to produce a change in perspective.     

Isolation,identification and characterization of Staphylococcus sp. from Indian ethnic fermented fish product

Staphylococci from Sheedal of Northeast India was isolated, identified and characterized. All the isolated staphylococci were found to be coagulase negative. Based on the rpoB gene sequences followed by analysis using NCBI-BLAST software, seven species of Staphylococcus namely, S. piscifermentans, S. condimenti, S. arlettae, S. sciuri, S. warneri, S. nepalensis and S. hominis were recognized. Phylogenetic analyses revealed three major cluster groups. All the seven Staphylococcus showed their NaCl tolerance from 2 to 8%. No species was able to grow at 55°C. Except S. arlettae and S. sciuri, all the isolated staphylococcal species exhibited growth at pH 4–8. No isolated species was able to ferment mannitol, sucrose and arabinose. All the species exhibited moderate to maximum proteolytic and lipolytic activities. All the seven species were found to be sensitive to the antibiotics, namely, erythromycin, norfloxacin, ampicillin, streptomycin and vancomycin, whereas all were resistant to co-trimoxazole. Only S. piscifermentans was found antagonist to Salmonella enterica, Escherichia coli and Bacillus subtilis, although the clear zone was minimal. All the staphylococcal species except S. arlettae and S. sciuri exhibited hydrophobicity ranging from 25 to 66%. The observed characteristics of isolated Staphylococci from Sheedal revealed their role in fish fermentation.     

Site,trigger, quenching mechanism and recovery of non-photochemical quenching in cyanobacteria: recent updates

Femtosecond transient absorption was used to study excitation decay in monomeric and trimeric cyanobacterial Photosystem I (PSI) being prepared in three states: (1) in aqueous solution, (2) deposited and dried on glass surface (either conducting or non-conducting), and (3) deposited on glass (conducting) surface but being in contact with aqueous solvent. The main goal of this contribution was to determine the reason of the acceleration of the excitation decay in dried PSI deposited on the conducting surface relative to PSI in solution observed previously using time-resolved fluorescence (Szewczyk et al., Photysnth Res 132(2):111–126, 2017). We formulated two alternative working hypotheses: (1) the acceleration results from electron injection from PSI to the conducting surface; (2) the acceleration is caused by dehydration and/or crowding of PSI proteins deposited on the glass substrate. Excitation dynamics of PSI in all three types of samples can be described by three main components of subpicosecond, 3–5, and 20–26 ps lifetimes of different relative contributions in solution than in PSI-substrate systems. The presence of similar kinetic components for all the samples indicates intactness of PSI proteins after their deposition onto the substrates. The kinetic traces for all systems with PSI deposited on substrates are almost identical and they decay significantly faster than the kinetic traces of PSI in solution. We conclude that the accelerated excitation decay in PSI-substrate systems is caused mostly by dense packing of proteins.     

Upf proteins: highly conserved factors involved in nonsense mRNA mediated decay

Over 10% of genetic diseases are caused by mutations that introduce a premature termination codon in protein-coding mRNA. Nonsense-mediated mRNA decay (NMD) is an essential cellular pathway that degrades these mRNAs to prevent the accumulation of harmful partial protein products. NMD machinery is also increasingly appreciated to play a role in other essential cellular functions, including telomere homeostasis and the regulation of normal mRNA turnover, and is misregulated in numerous cancers. Hence, understanding and designing therapeutics targeting NMD is an important goal in biomedical science. The central regulator of NMD, the Upf1 protein, interacts with translation termination factors and contextual factors to initiate NMD specifically on mRNAs containing PTCs. The molecular details of how these contextual factors affect Upf1 function remain poorly understood. Here, we review plausible models for the NMD pathway and the evidence for the variety of roles NMD machinery may play in different cellular processes.     

NADH oxidase and fumarate reductase of Ancylostoma ceylanicum.

Ancylostoma ceylanicum, the hookworm parasite of cat, dog and man, was found to contain NADH and/or NADPH oxidase as well as fumarate reductase activities. Both the enzyme systems were predominantly located in the membranes of mitochondrial-rich preparations. The membranes also exhibited the presence of a reduced pyridine nucleotide transhydrogenase activity which transferred hydrogen from NADPH to NAD. Amongst respiratory inhibitors, rotenone (Site I inhibitor) markedly depressed both NADH oxidase and fumarate reductase while others, namely antimycin-A, KCN and azide, had a lesser effect.