Seasonal Abundance of Acanthamoeba rhysodes (Singh, 1952) (Protozoa: Gymnamoebia) in a Mangrove Litter-Soil Ecosystem of Gangetic-Estuary,India1,2

Acanthamoeba rhysodes has been found to be a predominant intertidal benthic gymnamoeba in the mangrove ecosystem of Sundarbans of lower deltaic Bengal, facing the Bay. The sampling zones under study were the highest high tide regions, with characteristic mangrove litter-soil, inundated twice per month during the highest ebb of spring tide. Population abundance of this species, both in its trophic and cystic forms in the three distinct seasonal periods of pre-monsoon (March to June), monsoon (July to October), and post-monsoon (November to February) has been surveyed for over two years. These seasonal periods affect the physico-chemical parameters of the habitat substrata, including temperature, pH, and salinity. It has been found that the overall number of organisms per gram of soil attains peak value during the monsoon period. This value comes down in post-monsoon samples and is the least in pre-monsoon ones.     

Effect of short-and long-term exposure to low environmental temperature on brain regional GABA metabolism

Single exposure of adult male rats to low environmental temperature (LET, 12 ± 0.5°C) for 2 h significantly increased the hypothalamic and striatal GABA levels without affecting those in other regions of brain. The activity of glutamate decarboxylase (GAD) was elevated in hypothalamus (H) and corpus striatum (CS) under these conditions. GABA accumulation rate (measured with ethanolamine-O-sulfate, an inhibitor of GABA-transaminase) was also increased in both H and CS of rats exposed to LET for 2 h. Unlike after a single exposure, the repeated exposure (2 h/day) for 7, 15, and 30 onsecutive days did not change the hypothalamic GABA metabolism. No change in GABA metabolism was observed in CS when rats were repeatedly exposed to LET for 7 consecutive days. Prolongation of repeated exposure to LET (2 h/day) for 15 and 30 consecutive days decreased the striatal GABA level and increased the activity of GABA-transaminase, although GAD activity was not altered under these conditions. These results suggest that single exposure to LET accelerates GABA synthesis and may reduce the GABAergic activity in both H and CS; whereas repeated exposure to LET for 15 or 30 consecutive days enhances GABAergic activity with the stimulation of GABA utilization only in CS without affecting its synthesizing process. Thus, it may be suggested that the hypothalamic and striatal GABA system may play a characteristic role in response to short-and long-term exposure to LET.     

Pentylenetetrazol: Effect on carbaryl-induced changes of serotonin metabolism in pons-medulla of rat brain

Oral administration of carbaryl to adult male albino rats produced a dose dependent increase in the steady state level of 5-hydroxytryptamine (5-HT) at 1.00 h in pons-medulla (PM). 5-Hydroxyindole acetic acid (5-HIAA) concentration was significantly elevated only in response to a higher dose of this pesticide under similar conditions. A time course study with carbaryl and pentylenetetrazol (PTZ) showed a characteristic elevation of the steady state level of 5-HT in PM, but the 5-HIAA level was significantly elevated at 0.5 h only after carbaryl treatment. No significant change of the 5-HIAA level was evident after administration of PTZ alone or in combination with carbaryl. Tryptophan concentration was significantly elevated in PM at 0.5 h after carbaryl treatment and at 1.0 h after carbaryl + PTZ treatment. No significant change of tryptophan concentration was evident after the administration of PTZ alone under similar conditions. Measurement of (1) pargyline induced (a) accumulation of 5-HT and (b) depletion of 5-HIAA levels, and (2) probenecid-induced accumulation of 5-HIAA level in presence and absence of carbaryl and revealed that carbaryl accelerated the synthesis as well as the breakdown of 5-HT, whereas PTZ alone or in combination with carbaryl accelerated the synthesis of 5-HT without affecting its catabolism. The potency of this pesticide in elevating the pargyline-induced accumulation of 5-HT is in the order of carbaryl + PTZ greater than PTZ congruent to carbaryl. These results suggest that the carbaryl-induced increase in the synthesis of 5-HT is potentiated, and the turnover is reduced, in PM when PTZ is administered to the carbaryl-intoxicated rats.     

Molecular characterization and expression analysis of two crucial MAPKs- jnk1 and erk1 as cellular signal transducers in Labeo rohita in response to PAMPs stimulation and pathogenic invasion

Mitogen-activated protein kinases (MAPKs) are crucial Ser/Thr protein kinases that play important roles in innate immunity by converting extracellular stimuli into a wide range of cellular responses, including the production of cytokines. In this study, two MAPK genes, jnk1 and erk1, were cloned and characterized in rohu (Labeo rohita), a commercially important freshwater fish species in the Indian subcontinent. In healthy rohu, both jnk1 and erk1 gene expressions were highest in the spleen as compared to gill, liver, blood and kidney tissues. In vitro stimulation of the L. rohita gill (LRG) cell line with γ-D-glutamyl-meso-diaminopimelic acid, muramyl dipeptide and polyinosinic: polycytidylic acid (poly I:C) resulted in significantly enhanced expressions of jnk1 and erk1 genes. In the in vivo experiments, jnk1 and erk1 gene expressions were also enhanced in lipopolysaccharides and poly I:C-treatment. Infection of rohu fingerlings with Aeromonas hydrophila and Bacillus subtilis revealed significantly enhanced expressions of the jnk1 and erk1 genes in all of the tested organs/tissues. Together these results imply the important role of jnk1 and erk1 genes in fish during pathogenic invasion and diseases.     

Fatty acid-induced angiogenesis in first trimester placental trophoblast cells: Possible roles of cellular fatty acid-binding proteins

Angiogenesis is involved in the growth of new blood vessels from the existing one. Consequently, angiogenesis plays an indispensable role in tissue growth and repair including early placentation processes. Besides angiogenic growth factors (vascular endothelial growth factor (VEGF), angiopoietin-like 4 (ANGPTL4), placental growth factor (PlGF), platelet derived growth factor (PDGF), fibroblast growth factors (FGF)), dietary fatty acids (c>16) also directly or indirectly modulate angiogenic processes in tumors and other cell systems. Usually n − 3 fatty acids inhibit whereas n − 6 fatty acids stimulate angiogenesis in tumors and other cells. Contrary to this, docosahexaenoic acid, 22:6n − 3 (DHA) and other fatty acids including conjugated linoleic acid stimulate angiogenesis in placental first trimester cells. In addition to the stimulation of expression of major angiogenic factors such as VEGF and ANGPTL4, fatty acids also stimulate expression of intracellular fatty acid-binding proteins (FABPs) FABP-4 and FABP-3 those are known to directly modulate angiogenesis. Emerging data indicate that FABPs may be involved in the angiogenesis process. This paper reviews the fatty acid mediated angiogenesis process and the involvement of their binding proteins in these processes.     

Can Carnosine Prevent the Aging-Induced Changes of Blood Platelet and Brain Regional Monoamine Oxidase-A mRNA in Relation to its Activity?

It is well known that the monoamine oxidase (MAO) activity deregulates during aging along with anti-oxidant activity. Carnosine (β-Ala-l-His) is an endogenous dipeptide biomolecule, having both anti-oxidant and anti-glycating properties. The present study deals with the effect of carnosine on aging-induced changes in MAO-A mRNA expression of brain regions and blood platelets in relation to their MAO-A activity. Results showed that aging significantly and characteristically increased the brain regional MAO-A mRNA whereas, in blood platelets it was significantly reduced with an increase in blood platelet counts. Carnosine attenuated both aging-induced (i) increase in brain regional MAO-A mRNA expression and blood platelet count, (ii) decrease in blood platelet MAO-A mRNA expression and its (platelet MAO-A) activity without affecting the young rats’ brain regions and platelet. The present results thus suggest that carnosine attenuated and restored the aging-induced (a) increase of platelet count and (b) changes in brain regional and blood platelet MAO-A mRNA expression and (c) decrease in platelet MAO-A activity, towards their respective basal level that were observed in young rats.     

Morphological and molecular divergence of Indian hill trout,Barilius bendelisis (Hamilton, 1822) stocks from different Rivers in Indo‐Burma biodiversity hotspot: Does river altitude and Dam play a role?

The present study explains the intraspecific variation in Indian Hill trout (Barilius bendelisis) on the basis of image based truss network system and D‐loop region of mtDNA. A total of 210 samples were collected from three different rivers (Teesta, Kameng and Myntudu River) of North East India in Indo‐Burma Biodiversity Hotspot. By using the software applications (tpsDig version 2.1 and PAST), a total of 25 morphometric measurements were generated from 10 landmarks. The Analysis of Variance (ANOVA), Factor Analysis (FA) and Discriminate Function Analysis (DFA) showed, out of the total variations, factor 1 explained 46.74% while factor 2 and factor 3 explained 27.14% and 11.92%, respectively. Using these variables 83.33% of the cross‐validated specimens were classified into distinct groups. Analysis of Molecular Variance (AMOVA) and pairwise Fst value for D‐loop region of mtDNA also showed high to medium level of genetic variation among the stocks and within the stocks. We conclude that the observed discrete stocks might be the result of changing environmental conditions in different rivers of the hotspot as the rivers are present at different altitudinal labels. It is also believed that the variation might be due to the construction of barrages across the river which hinder the mixing among the stocks.