Leishmania Specific CD4 T Cells Release IFNγ That Limits Parasite Replication in Patients with Visceral Leishmaniasis

Visceral leishmaniasis (VL) is associated with increased circulating levels of multiple pro-inflammatory cytokines and chemokines, including IL-12, IFNγ, and TNFα, and elevated expression of IFNγ mRNA in lesional tissue such as the spleen and bone marrow. However, an immunological feature of VL patients is that their peripheral blood mononuclear cells (PBMCs) typically fail to respond to stimulation with leishmanial antigen. Unexpectedly, it was recently shown that Leishmania specific IFNγ, can readily be detected when a whole blood stimulation assay (WBA) is used. We sought to define the conditions that permit whole blood cells to respond to antigen stimulation, and clarify the biological role of the IFNγ found to be released by cells from VL patients. CD4+ T cells were found to be crucial for and the main source of the IFNγ production in Leishmania stimulated whole blood (WB) cultures. Complement, antibodies and red blood cells present in whole blood do not play a significant role in the IFNγ response. The IFNγ production was reduced by blockade of human leukocyte antigen (HLA)-DR, indicating that the response to leishmanial antigens observed in WB of active VL patients is a classical HLA- T cell receptor (TCR) driven reaction. Most importantly, blockade of IFNγ in ex-vivo splenic aspirate cultures demonstrated that despite the progressive nature of their disease, the endogenous IFNγ produced in patients with active VL serves to limit parasite growth.     

RAPD, SCAR and conserved 18S rDNA markers for a red-listed and endemic medicinal plant species, Knema andamanica (Myristicaceae)

Knema andamanica is a red-listed endemic medicinal species of Myristicaceae restricted to Andaman and Nicobar (A&N) Islands, India. This species is used in tribal medicines and has immense bioprospective potential. With a view to generate suitable genomic markers for classification and identification, we have generated RAPD, SCAR and conserved 18S rDNA markers from K. andamanica. A unique 585 bp fragment, that distinguished it from seven other related species of Myristicaceae was first amplified using the random primer OPE 06 and converted to SCAR marker (GenBank accession # JN228256). The conserved sequences of 18S rDNA loci from K. andamanica were also amplified and sequenced (GenBank accession #JN228265). The sequence revealed deviations including 18 variable regions and 15 indels that were unique to K. andamanica. These markers can help in definite identification of K. andamanica even at the juvenile stages.     

Structural and functional diversity of Entamoeba histolytica calcium-binding proteins

Entamoeba histolytica (E. histolytica) is an etiological agent of human amoebic colitis, and it causes a high level of morbidity and mortality worldwide, particularly in developing countries. Ca²⁺ plays a pivotal role in amoebic pathogenesis, and Ca²⁺-binding proteins (CaBPs) of E. histolytica appear to be a major determinant in this process. E. histolytica has 27-EF-hand containing CaBPs, suggesting that this organism has complex Ca²⁺ signaling cascade. E. histolytica CaBPs share (29–47%) sequence identity with ubiquitous Ca²⁺-binding protein calmodulin (CaM); however, they do not show any significant structural similarity, indicating lack of a typical CaM in this organism. Structurally, these CaBPs are very diverse among themselves, and perhaps such diversity allows them to recognize different cellular targets, thereby enabling them to perform a range of cellular functions. The presence of such varied signaling molecules helps parasites to invade host cells and advance in disease progression. In the past two decades, tremendous progress has been made in understanding the structure of E. histolytica CaBPs by using the X-ray or NMR method. To gain greater insight into the structural and functional diversity of these amoebic CaBPs, we analyzed and compiled all the available literature. Most of the CaBPs has about 150 amino acids with 4-EF hand or EF-hand-like sequences, similar to CaM. In a few cases, all the EF-hand motifs are not capable of binding Ca²⁺, suggesting them to be pseudo EF-hand motifs. The CaBPs perform diverse cellular signaling that includes cytoskeleton remodeling, phagocytosis, cell proliferation, migration of trophozoites, and GTPase activity. Overall, the structural and functional diversity of E. histolytica CaBPs compiled here may offer a basis to develop an efficient drug to counter its pathogenesis.     

Antioxidant and Anti-hypertensive Bioactive Peptides from Indian Mackerel Fish Waste

International Journal of Peptide Research and Therapeutics - India ranks second in the harvesting and production of fish. The discard of fish is near about 20–40% of total fish weight....     

Chronic hyperprolactinemia depletes hypothalamic dopamine concentrations in male rats

The tuberoinfundibular dopamine (TIDA) system appears to tonically inhibit pituitary prolactin secretion while moderate elevations in serum prolactin levels, in turn, augment the turnover rate of dopamine (DA) without affecting the steady state concentrations of DA in the TIDA neurons (1–5). The present study demonstrates that chronic elevations in serum prolactin, to greater than 2,000 ng/ml, induced by the prolactin secreting MtTW15 tumor, decreased DA concentrations by 47% in the median eminence-arcuate nucleus (ME-ARC) region, by 43% in the medial basal hypothalamus (MBH) and 14% in the preoptic area-anterior hypothalamic region (POA-AH) without influencing the norepinephrine levels in these regions. Thus, chronic stimulation of hypothalamic DA neurons by prolactin may lead to depletion of DA concentrations and this may be an important factor in the reduced DA levels observed in hyperprolactinemia of senescent rats or that produced by chronic estrogen treatment.     

Imaging of Calcium Channels During Polarity Induction in Plant Cells

Understanding the molecular basis of polarity induction in plant cells is a research aspect that extends from signal perception and transduction to morphogenesis. A gradient of cytoplasmic ion fluxes generated through ion channels plays a crucial role in subsequent events leading to polar growth. Convincing evidence is now available implicating temporal and spatial distribution of Ca²⁺ in cytoplasm, generated by localized activity of calcium channels, as the early biochemical events associated with polarity induction. Ion channel antagonists are common tools for studying ion channel structure and function. Coupled with a fluorescent dyes, calcium channel antagonists (phenylalkylamine and dihydropyridine), have been used to localize L-type calcium channels. Additionally, the advent of Confocal Laser Scanning Microscopy has made possible the visualization of Ca²⁺ channels in plant cells. Persisting problems of dye loading and their cellular compartmentation have been addressed by developing a variety of experimental protocols. Present article highlights the current state of our understanding of these concepts, methodologies and their applications in different aspects of plant development.     

Influence of Residue 22 on the Folding, Aggregation Profile, and Toxicity of the Alzheimer's Amyloid β Peptide

Several biophysical techniques have been used to determine differences in the aggregation profile (i.e., the secondary structure, aggregation propensity, dynamics, and morphology of amyloid structures) and the effects on cell viability of three variants of the amyloid β peptide involved in Alzheimer's disease. We focused our study on the Glu²² residue, comparing the effects of freshly prepared samples and samples aged for at least 20 days. In the aged samples, a high propensity for aggregation and β-sheet secondary structure appears when residue 22 is capable of establishing polar (Glu²² in wild-type) or hydrophobic (Val²² in E22V) interactions. The Arctic variant (E22G) presents a mixture of mostly disordered and α-helix structures (with low β-sheet contribution). Analysis of transmission electron micrographs and atomic force microscopy images of the peptide variants after aging showed significant quantitative and qualitative differences in the morphology of the formed aggregates. The effect on human neuroblastoma cells of these Aβ_12-28 variants does not correlate with the amount of β-sheet of the aggregates. In samples allowed to age, the native sequence was found to have an insignificant effect on cell viability, whereas the Arctic variant (E22G), the E22V variant, and the slightly-aggregating control (F19G-F20G) had more prominent effects.