Phosphatidylinositol hydrolysis and phosphatidylinositol 4',5-diphosphate hydrolysis are separable responses during secretagogue action in the rat pancreas

Rat pancreatic fragments and acinar preparations were incubated in vitro to characterize further the changes in phosphoinositide metabolism that occur during secretagogue action. Two distinct responses were discernible. The first response, most notably involving a decrease in phosphatidylinositol content, was (a) observed at lower carbachol concentrations in dose-response studies, (b) inhibited by incubation in Ca2+-free media containing 1 mM EGTA, (c) associated with increases in inositol monophosphate production, and (d) provoked by all tissue secretagogues (carbachol, cholecystokinin, secretin, insulin, dibutyryl cAMP and the ionophore A23187), regardless of whether their mechanism of action primarily involved Ca2+ mobilization or cAMP generation. This decrease in phosphatidylinositol content was at least partly due to phospholipase C (and/or D) activation, as evidenced by the increase in inositol monophosphate. The second response, most notably involving markedly increased incorporation of 32PO4 into phosphatidic acid and phosphatidylinositol, was (a) observed at higher carbachol concentrations, (b) not influenced by incubation in Ca2+-free media containing 1 mM EGTA, and (c) associated with increases in inositol triphosphate production. This 32PO4 turnover response was probably largely the result of phospholipase C-mediated hydrolysis of phosphatidylinositol 4',5'-diphosphate, which, as shown previously, also occurs at higher carbachol concentrations and is insensitive to comparable EGTA-induced Ca2+ deficiency. This phosphatidylinositol 4',5'-diphosphate hydrolysis response was only observed in the action of agents (carbachol and cholecystokinin) which mobilize Ca2+ via activation of cell surface receptors. The present results indicate that phosphatidylinositol and phosphatidylinositol 4',5'-diphosphate hydrolysis are truly separable responses to secretagogues acting in the rat pancreas. Furthermore, phosphatidylinositol 4',5'-diphosphate, rather than phosphatidylinositol hydrolysis is more likely to be associated with receptor activation and Ca2+ mobilization.     

Dispersions of repolarization and ventricular arrhythmogenesis: Lessons from animal models

Sudden cardiac death resulting from ventricular arrhythmogenesis is a leading cause of mortality in the developed world, accounting for up to 400,000 deaths per year in the US alone. Within the past forty years we have taken considerable leaps forward in our understanding of the causes and mechanisms underlying cardiac arrhythmias, particularly in the setting of inherited and acquired dysfunctions in ionic currents which constitute human long QT syndrome (LQTS). Impaired repolarization seen in LQTS commonly gives rise to an altered dispersion of repolarization, which is considered to provide the functional substrate necessary for the perpetuation of lethal arrhythmias. This review examines the bases for arrhythmias arising from repolarization heterogeneities and explores the applicability of the genetically amenable mouse for the study of arrhythmias arising from such mechanisms.     

A multivariate analysis of health risk assessment,phytoremediation potential,and biochemical attributes of Spinacia oleracea exposed to cadmium in the presence of organic amendments under hydroponic conditions

Abstract

Cadmium (Cd) phytoremediation potential and its accumulation in edible and nonedible plant tissues is the function of various biochemical processes taking place inside plants. This study assessed the impact of organic ligands on Cd phyto uptake and different biophysiochemical processes of Spinacia oleracea L., and associated health hazards. Plants were exposed to Cd alone and chelated with citric acid (CA) and ethylenediaminetetraacetic acid (EDTA). Results revealed that the effect of Cd on lipid peroxidation, H₂O₂ production and pigment contents varied greatly with its applied level and the type of organic ligand. Moreover, the effect was more prominent in root tissues than leaf tissues and for high concentrations of Cd and organic ligands. Cadmium accumulation increased by 90 and 74% in roots and leaves, respectively, with increasing Cd levels (25–100?µM). Cadmium exposure at high levels caused lipid peroxidation in roots only. Application of both CA and EDTA slightly diminished Cd toxicity with respect to pigment contents, lipid peroxidation and hydrogen peroxide (H₂O₂) contents. Hazard quotient (HQ) of Cd was <1.00 for all the treatments. Under nonlinear effect of treatments, multivariate analysis can be an effective tool to trace overall effects/trends.     

The endangered forests of Bangladesh: why the process of implementation of the Convention on Biological Diversity is not working

Bangladesh has been a signatory to the Convention on Biological Diversity (CBD) although implementation of the convention has been poor. We independently assessed the extent to which the program of work (POW) of the CBD has been implemented in Bangladesh by carrying out workshops involving local communities, conservation organizations, universities, and government departments involved in forest conservation. Our analyses indicate that there is little or no understanding of the ecosystem approach that is central to the CBD; forestry practices remain primitive and largely ineffective; forest destruction continues at high rates; restoration of degraded forests are minimal; protected areas are small and ineffective; indigenous peoples’ rights are nominal and are outside any legislation; threats to species have been identified, but little is being done to reduce threats; there is no work on pollution and its mitigation; some work has been done to adapt to climate change; the institutional environment does not enable effective implementation of the ecosystem approach; laws and policies are ineffective; institutional capacity is poor; government will is limited or totally lacking; and knowledge base remains poor, although reporting has improved and various strategic plans have been formulated but never implemented. Thus, the implementation of CBD in Bangladesh requires systemic changes in policy at the institutional levels as well as complementary changes in attitudes and avenues of alternate income generation.     

Conserved Gene Order and Expanded Inverted Repeats Characterize Plastid Genomes of Thalassiosirales

Diatoms are mostly photosynthetic eukaryotes within the heterokont lineage. Variable plastid genome sizes and extensive genome rearrangements have been observed across the diatom phylogeny, but little is known about plastid genome evolution within order- or family-level clades. The Thalassiosirales is one of the more comprehensively studied orders in terms of both genetics and morphology. Seven complete diatom plastid genomes are reported here including four Thalassiosirales: Thalassiosira weissflogii, Roundia cardiophora, Cyclotella sp. WC03_2, Cyclotella sp. L04_2, and three additional non-Thalassiosirales species Chaetoceros simplex, Cerataulina daemon, and Rhizosolenia imbricata. The sizes of the seven genomes vary from 116,459 to 129,498 bp, and their genomes are compact and lack introns. The larger size of the plastid genomes of Thalassiosirales compared to other diatoms is due primarily to expansion of the inverted repeat. Gene content within Thalassiosirales is more conserved compared to other diatom lineages. Gene order within Thalassiosirales is highly conserved except for the extensive genome rearrangement in Thalassiosira oceanica. Cyclotella nana, Thalassiosira weissflogii and Roundia cardiophora share an identical gene order, which is inferred to be the ancestral order for the Thalassiosirales, differing from that of the other two Cyclotella species by a single inversion. The genes ilvB and ilvH are missing in all six diatom plastid genomes except for Cerataulina daemon, suggesting an independent gain of these genes in this species. The acpP1 gene is missing in all Thalassiosirales, suggesting that its loss may be a synapomorphy for the order and this gene may have been functionally transferred to the nucleus. Three genes involved in photosynthesis, psaE, psaI, psaM, are missing in Rhizosolenia imbricata, which represents the first documented instance of the loss of photosynthetic genes in diatom plastid genomes.     

Chimerical categories: caste, race, and genetics

Is discrimination based on caste equivalent to racism? This paper explores the complex relationship between genetic, race and caste. It also discusses the debate over the exclusion of a discussion of caste‐based discrimination at the 2001 World Conference against Racism, Racial Discrimination, Xenophobia and Related Intolerance held in Durban, South Africa.     

Complete Genome Sequence of Mycobacterium vaccae Type Strain ATCC 25954

Mycobacterium vaccae is a rapidly growing, nontuberculous Mycobacterium species that is generally not considered a human pathogen and is of major pharmaceutical interest as an immunotherapeutic agent. We report here the annotated genome sequence of the M. vaccae type strain, ATCC 25954.     

MHD Mixed Convective Peristaltic Motion of Nanofluid with Joule Heating and Thermophoresis Effects

The primary objective of present investigation is to introduce the novel aspect of thermophoresis in the mixed convective peristaltic transport of viscous nanofluid. Viscous dissipation and Joule heating are also taken into account. Problem is modeled using the lubrication approach. Resulting system of equations is solved numerically. Effects of sundry parameters on the velocity, temperature, concentration of nanoparticles and heat and mass transfer rates at the wall are studied through graphs. It is noted that the concentration of nanoparticles near the boundaries is enhanced for larger thermophoresis parameter. However reverse situation is observed for an increase in the value of Brownian motion parameter. Further, the mass transfer rate at the wall significantly decreases when Brownian motion parameter is assigned higher values.     

Qualitative and quantitative variations in withanolides and expression of some pathway genes during different stages of morphogenesis in Withania somnifera Dunal

Withania somnifera Dunal is an important and extensively studied medicinal plant; however, there is no report available that relates withanolide content and its profile in relation to the expression of pathway genes during different morphogenic stages. In this study, withanolide A, withaferin A, and withanone, the major withanolides of W. somnifera, were measured in different in vitro stages during organogenesis, viz., shoot to root (direct rhizogenesis)/root to shoot (indirect via callus phase) transition vis-à-vis expression levels of key pathway genes involved in withanolide biosynthetic pathways. The morphogenic transitions were found to be tightly linked to the pattern of accumulation of withanolides. The high expression levels of most of the pathway genes in in vitro shoots in comparison to in vitro root and callus tissues exhibited a direct co-relation with the maximum withanolide content (>2.7 mg/gDW). The biogenesis of withaferin A, a major constituent of the leaves, was however found to be tightly linked to shoots/green tissue. In addition, we were also able to establish an efficient regeneration system from roots for their further utilization in biotechnological applications.