Abundance, species composition of microzooplankton from the coastal waters of Port Blair, South Andaman Island

ABSTRACT: BACKGROUND: Microzooplankton consisting of protists and metazoa <200 mum. It displays unique feeding mechanisms and behaviours that allow them to graze cells up to five times their own volume. They can grow at rates which equal or exceed prey growth and can serve as a viable food source for metazoans. Moreover, they are individually inconspicuous, their recognition as significant consumers of oceanic primary production. The microzooplankton can be the dominant consumers of phytoplankton production in both oligo- and eutrophic regions of the ocean and are capable of consuming >100% of primary production. RESULTS: The microzooplankton of the South Andaman Sea were investigated during September 2011 to January 2012. A total of 44 species belong to 19 genera were recorded in this study. Tintinnids made larger contribution to the total abundance (34%) followed in order by dinoflagellates (24%), ciliates (20%) and copepod nauplii (18%). Foraminifera were numerically less (4%). Tintinnids were represented by 20 species belong to 13 genera, Heterotrophic dinoflagellates were represented by 17 species belong to 3 genera and Ciliates comprised 5 species belong to 3 genera. Eutintinus tineus, Tintinnopsis cylindrical, T. incertum, Protoperidinium divergens, Lomaniella oviformes, Strombidium minimum were the most prevalent microzooplankton. Standing stock of tintinnids ranged from 30--80 cells.L-1 and showed a reverse distribution with the distribution of chlorophyll a relatively higher species diversity and equitability was found in polluted harbour areas. CONCLUSIONS: The change of environmental variability affects the species composition and abundance of microzooplankton varied spatially and temporarily. The observations clearly demonstrated that the harbor area differed considerably from other area in terms of species present and phytoplankton biomass. Further, the phytoplankton abundance is showed to be strongly influenced by tintinnid with respect to the relationship of prey--predator. Consequently, further investigation on microzooplankton grazing would shed light on food web dynamics.     

Anti-fibrotic cardio protective efficacy of aminoguanidine against streptozotocin induced cardiac fibrosis and high glucose induced collagen up regulation in cardiac fibroblasts

This study mainly focuses on cardio protective anti-fibrotic activity of aminoguanidine against streptozotocin induced cardiac fibrosis and high glucose induced collagen accumulation in cardiac fibroblasts. Dysregulation of matrix metalloproteinase especially 2 and 9 were considered to be responsible for the abnormal collagen deposition, which resulting improper cardiac contractile function in diabetic mice. Mice received a single dose of streptozotocin (100 mg/kg) through tail vein to induce diabetes. Normal and diabetic mice received aminoguanidine orally (100 mg/kg/day) throughout the study period of 8 weeks. Cardiac fibroblasts cultured and exposed to high glucose, aminoguanidine and both for 48 h. Collagen quantitatively estimated in both in vivo and in vitro models. Altered structural changes were studied using the Masson tri-chrome staining, TEM images of cardiac sections. Increased collagen and metalloproteinase activities were confirmed using gelatin zymography, western blotting and gene expression studies. The exact mechanism responsible for high glucose induced collagen up regulation in diabetic heart was incompletely understood. From this above in vivo and in vitro results, we conclude that, the cardio protective anti fibrotic activity of amino guanidine was mainly attributed by exhibiting the inhibitory efficacy against streptozotocin and high glucose induced collagen accumulation probably by inhibiting high glucose altered metalloproteinase-2 and -9 activities.     

Confocal FRET microscopy to measure clustering of ligand-receptor complexes in endocytic membranes

The dynamics of protein distribution in endocytic membranes are relevant for many cellular processes, such as protein sorting, organelle and membrane microdomain biogenesis, protein-protein interactions, receptor function, and signal transduction. We have developed an assay based on Fluorescence Resonance Energy Microscopy (FRET) and novel mathematical models to differentiate between clustered and random distributions of fluorophore-bound molecules on the basis of the dependence of FRET intensity on donor and acceptor concentrations. The models are tailored to extended clusters, which may be tightly packed, and account for geometric exclusion effects between membrane-bound proteins. Two main criteria are used to show that labeled polymeric IgA-ligand-receptor complexes are organized in clusters within apical endocytic membranes of polarized MDCK cells: 1), energy transfer efficiency (E%) levels are independent of acceptor levels; and 2), with increasing unquenched donor: acceptor ratio, E% decreases. A quantitative analysis of cluster density indicates that a donor-labeled ligand-receptor complex should have 2.5-3 labeled complexes in its immediate neighborhood and that clustering may occur at a limited number of discrete membrane locations and/or require a specific protein that can be saturated. Here, we present a new sensitive FRET-based method to quantify the co-localization and distribution of ligand-receptor complexes in apical endocytic membranes of polarized cells.     

Beneficial effects of DL-alpha-lipoic acid on cyclophosphamide-induced oxidative stress in mitochondrial fractions of rat testis

The present study investigated the protective efficacy of dl-alpha-lipoic acid on the peroxidative damage and abnormal antioxidant levels in the mitochondrial fraction of testis in cyclophosphamide (CP) administered rats. Male Wistar rats of 140+/-20 g were categorized into four groups. Two groups were administered CP (15 mg/kg body weight once a week for 10 weeks by oral gavage) to induce testicular toxicity; one of these groups received lipoic acid treatment (35 mg/kg body weight intraperitoneally once a week for 10 weeks, 24 h prior to CP administration). A vehicle-treated control group and a lipoic acid drug control group were also included. The mitochondrial fraction of untreated CP-exposed testis showed 1.84-fold increase in lipid peroxidation, along with a significant (P<0.001) increase in hydrogen peroxide levels. In CP-exposed rats, we observed abnormal changes in the activities/levels of mitochondrial enzymic (superoxide dismutase, glutathione peroxidase and glutathione reductase) and non-enzymic (reduced glutathione, ascorbate and alpha-tocopherol) antioxidants. CP-treated rats also showed decline in the activities of mitochondrial enzymes such as succinate dehydrogenase, malate dehydrogenase and isocitrate dehydrogenase. In contrast, rats pretreated with lipoic acid showed normal lipid peroxidation and antioxidant defenses, thereby showing the protection rendered by lipoic acid.     

Characterization of copABCD operon from a copper-sensitive Pseudomonas putida strain

We describe an operon, copABCD, that encodes copper-binding and sequestering proteins for copper homeostasis in the copper-sensitive strain Pseudomonas putida PNL-MK25. This is the second operon characterized as being involved in copper homeostasis, in addition to a P1-type ATPase encoded by cueAR, which was previously shown to be active in the same strain. In this study, 3 copper-responsive mutants were obtained through mini-Tn5::gfp mutagenesis and were found to exhibit reduced tolerance to copper. Sequencing analysis of the transposon-tagged region in the 3 mutants revealed insertions in 2 genes of an operon homologous to the copABCD of P. syringae and pcoABCD of Escherichia coli. Gene expression studies demonstrated that the P. putida copABCD is inducible starting from 3 micromol/L copper levels. Copper-sensitivity studies revealed that the tolerance of the mutant strains was reduced only marginally (only 0.16-fold) in comparison to a 6-fold reduced tolerance of the cueAR mutant. Thus, the cop operon in this strain has a minimal role when compared with its role both in other copper-resistant strains, such as P. syringae pv. syringae, and in the cueAR operon of the same strain. We propose that the reduced function of the copABCD operon is likely to be due to the presence of fewer metal-binding domains in the encoded proteins.     

miRNA in Parkinson's disease: From pathogenesis to theranostic approaches

Parkinson's disease (PD) is an age associated neurological disorder which is specified by cardinal motor symptoms such as tremor, stiffness, bradykinesia, postural instability, and non-motor symptoms. Dopaminergic neurons degradation in substantia nigra region and aggregation of αSyn are the classic signs of molecular defects noticed in PD pathogenesis. The discovery of microRNAs (miRNA) predicted to have a pivotal part in various processes regarding regularizing the cellular functions. Studies on dysregulation of miRNA in PD pathogenesis has recently gained the concern where our review unravels the role of miRNA expression in PD and its necessity in clinical validation for therapeutic development in PD. Here, we discussed how miRNA associated with ageing process in PD through molecular mechanistic approach of miRNAs on sirtuins, tumor necrosis factor-alpha and interleukin-6, dopamine loss, oxidative stress and autophagic dysregulation. Further we have also conferred the expression of miRNAs affected by SNCA gene expression, neuronal differentiation and its therapeutic potential with PD. In conclusion, we suggest more rigorous studies should be conducted on understanding the mechanisms and functions of miRNA in PD which will eventually lead to discovery of novel and promising therapeutics for PD.     

Characterization of fragrance in sorghum (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.) Moench) grain and development of a gene-based marker for selection in breeding

Fragrance is one of the most important and valued quality characters in sorghum and other foods and attracts a premium price in local and global trade. The allele of the SbBADH2 gene in fragrant sorghum cultivar E228 was characterized. A 1441 bp deletion extending from exon 13 to 15 was found rather than a deletion from exon 12 to 15 as had been reported earlier. This allowed the development and validation of a new perfect PCR-based marker for identification of fragrant sorghum accessions in breeding. The concentration of 2-acetyl-1-pyrroline (2AP) in the grain of this cultivar was estimated to be 6.5 ± 0.4 ppb using headspace solid-phase microextraction (HS-SPME) coupled with GC-MS. Flavor components of fragrant sorghum accession E228 (IC 568489) were analyzed and compared with the non-fragrant M35-1 cultivar. PCA analysis revealed that 2AP, benzothiazole, 2,3,5-trimethylpyridine, (1E)-1-ethylidene-1H-indene, cedrene, 2,4-bis(2-methyl-2-propanyl)phenol, 2-hexyl-1-octanol, and 2-butyl-1-octanol were among 25 compounds that were found in sorghum grain that may be contributing toward the aroma of fragrant sorghum. Proline and methylglyoxal contents were found to be higher in E228 than in M35-1, while SbBADH2 expression in E228 was half that in M35-1, suggesting a similar 2AP biosynthetic mechanism to that found in fragrant rice and soybean.     

Enhanced activation of pro-inflammatory cytokines in mice lacking natriuretic peptide receptor-A

Natriuretic peptide receptor-A (NPRA) is the principal receptor for the cardiac hormones ANP and BNP. Mice lacking NPRA develop progressive cardiac hypertrophy and congestive heart failure. However, the mechanisms responsible for hypertrophic growth in the absence of NPRA signaling are not yet known. In the present study, we determined whether deficiency of NPRA/cGMP signaling alters the cardiac pro-inflammatory cytokines gene expression in Npr1 (coding for NPRA) gene-knockout (Npr1(-/-)) mice exhibiting cardiac hypertrophy and fibrosis as compared with control wild-type (Npr1(+/+)) mice. A significant up-regulation of cytokine genes such as TNF-alpha (five-fold), IL-6 (three-fold) and TGF-beta1 (four-fold) were observed in mutant mice hearts lacking NPRA as compared with the age-matched wild-type mice. In parallel, NF-kappaB binding activity was almost five-fold greater in the nuclear extract of Npr1(-/-) mutant mice hearts as compared with wild-type Npr1(+/+) mice hearts. Guanylyl cyclase (GC) activity and cGMP levels were drastically reduced by 10- and 5-fold, respectively, in ventricular tissues of mutant mice hearts relative to wild-type controls. The present findings provide direct evidence that ablation of NPRA/cGMP signaling activates inflammatory cytokines, probably via NF-kappaB mediated signaling pathway, and is associated with hypertrophic growth of null mutant mice hearts.