Morphological and molecular characterization of new plant type core set for yield and culm strength traits in rice (Oryza sativa L.)

New plant type core set comprising indica and tropical japonica accessions along with checks were evaluated for yield and culm strength related traits and characterized with gene specific markers viz., Gn1a, DEP1, Ghd7, SPL14, GS5, TGW6 and SCM2. Analysis of variance revealed significant differences as well as presence of variability among the genotypes for all the traits. Seven genotypes (IRGC25510, IRGC1742, Haorei machang, Azhoghi, Thangmoi, BPT5204 and Swarnadhan) do not possess similar allele as that of the assessed genes based on combined analysis for all the traits and genes. Of them, four genotypes IRGC1742, Azhoghi, BPT5204 and Swarnadhan possess ideal trait combination (90–100 days to 50% flowering, 100–120 cm plant height, grain number of > 200, 11–15 productive tillers) but with weak culm can be ideal sources for identification of new genes for yield attributing traits and direct introgression of SCM2. Based on single trait-gene analysis, nine trait wise donors with high value for the trait (also with desirable plant type) but without similar allele of the corresponding gene were identified. One genotype IRGC7486 with high grain number (300), four genotypes (IRGC50448, IRGC43741, IRGC15147 and IRGC39111) with strong culm (1195–2655 g.f), three genotypes viz., IRGC15147, IRGC39111 and IRGC10658 with high panicle weight and one genotype Solumpiket with high 1000-grain weight and high panicle weight can be considered for identification of novel gene(s) for respective traits.

     

Toad‐kill: Prey diversity and preference of invasive guttural toads (Sclerophrys gutturalis) in Mauritius

The invertebrate communities of Mauritius host a high degree of endemism, but are also imperilled by an array of factors, including invasive predators. Since their introduction in 1922, guttural toads (Sclerophrys gutturalis) have spread across the island and have been implicated in the decline of a number of endemic invertebrate species. In this study, we examined the feeding habits of the invasive population of guttural toads from three naturally forested locations in Mauritius across multiple years by analysing their stomach content. We also measured the relative abundance of prey items on the landscape using pitfall traps and applied these data to determine prey preference using a Relativised Electivity Index. Insects, malacostracans and gastropods constituted the bulk of the toads' diet (48.7%, 33.4% and 11.8%, respectively), which also included several rare and endemic species. We further determined that insects and malacostracans were also the two most favoured prey taxa, relative to what was available on the landscape. Our investigation has generated several recommendations for future research and provides a fundamental understanding of the diet of guttural toads in the native forests of Mauritius.     

Convergence and divergence in lizard colour polymorphisms

Colour polymorphic species are model systems for examining the evolutionary processes that generate and maintain discrete phenotypic variation in natural populations. Lizards have repeatedly evolved strikingly similar polymorphic sexual signals in distantly related lineages, providing an opportunity to examine convergence and divergence in colour polymorphism, correlated traits and associated evolutionary processes. Herein, we synthesise the extensive literature on lizard colour polymorphisms in both sexes, including recent advances in understanding of the underlying biochemical, cellular and genetic mechanisms, and correlated behavioural, physiological and life-history traits. Male throat, head or ventral colour morphs generally consist of red/orange, yellow and white/blue morphs, and sometimes mixed morphs with combinations of two colours. Despite these convergent phenotypes, there is marked divergence in correlated behavioural, physiological and life-history traits. We discuss the need for coherence in morph classification, particularly in relation to ‘mixed’ morphs. We highlight future research directions such as the genetic basis of convergent phenotypes and the role of environmental variation in the maintenance of polymorphism. Research in this very active field promises to continue to provide novel insights with broad significance to evolutionary biologists.     

α-Glucosidase Inhibition by Usnic Acid Derivatives

This study investigated a set of new potential antidiabetes agents. Derivatives of usnic acid were designed and synthesized. These analogs and nineteen benzylidene analogs from a previous study were evaluated for enzyme inhibition of α-glucosidase. Analogs synthesized using the Dakin oxidative method displayed stronger activity than the pristine usnic acid (IC₅₀>200 μM). Methyl (2E,3R)-7-acetyl-4,6-dihydroxy-2-(2-methoxy-2-oxoethylidene)-3,5-dimethyl-2,3-dihydro-1-benzofuran-3-carboxylate ( 6b ) and 1,1′-(2,4,6-trihydroxy-5-methyl-1,3-phenylene)di(ethan-1-one) ( 6e ) were more potent than an acarbose positive control (IC₅₀ 93.6±0.49 μM), with IC₅₀ values of 42.6±1.30 and 90.8±0.32 μM, respectively. Most of the compounds synthesized from the benzylidene series displayed promising activity. (9bR)-2,6-Bis[(2E)-3-(2-chlorophenyl)prop-2-enoyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-1(9bH)-one ( 1c ), (9bR)-3,7,9-trihydroxy-8,9b-dimethyl-2,6-bis[(2E)-3-phenylprop-2-enoyl]dibenzo[b,d]furan-1(9bH)-one ( 1g ), (9bR)-2-acetyl-6-[(2E)-3-(2-chlorophenyl)prop-2-enoyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-1(9bH)-one ( 2d ), (9bR)-2-acetyl-6-[(2E)-3-(3-chlorophenyl)prop-2-enoyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-1(9bH)-one ( 2e ), (6bR)-8-acetyl-3-(4-chlorophenyl)-6,9-dihydroxy-5,6b-dimethyl-2,3-dihydro-1H-[1]benzofuro[2,3-f][1]benzopyran-1,7(6bH)-dione ( 3e ), (6bR)-8-acetyl-6,9-dihydroxy-5,6b-dimethyl-3-phenyl-2,3-dihydro-1H-[1]benzofuro[2,3-f][1]benzopyran-1,7(6bH)-dione ( 3h ), (6bR)-3-(2-chlorophenyl)-8-[(2E)-3-(2-chlorophenyl)prop-2-enoyl]-6,9-dihydroxy-5,6b-dimethyl-2,3-dihydro-1H-[1]benzofuro[2,3-f][1]benzopyran-1,7(6bH)-dione ( 4b ), and (9bR)-6-acetyl-3,7,9-trihydroxy-8,9b-dimethyl-2-[(2E)-3-phenylprop-2-enoyl]dibenzo[b,d]furan-1(9bH)-one ( 5c ) were the most potent α-glucosidase enzyme inhibitors, with IC₅₀ values of 7.0±0.24, 15.5±0.49, 7.5±0.92, 10.9±0.56, 1.5±0.62, 15.3±0.54, 19.0±1.00, and 12.3±0.53 μM, respectively.     

Interaction of acid exudates in chickpea with biological activity of Bacillus thuringiensis towards Helicoverpa armigera

The gram pod borer, Helicoverpa armigera, is one of the most important constraints to chickpea production. High acidity of chickpea exudates is associated with resistance to pod borer, H. armigera; however, acidic exudates in chickpea might influence the biological activity of the bacterium, Bacillus thuringiensis (Bt), applied as a foliar spray or deployed in transgenic plants for controlling H. armigera. Therefore, studies were undertaken to evaluate the biological activity of Bt towards H. armigera on chickpea genotypes with different amounts of organic acids. Significantly lower leaf feeding, larval survival and larval weights were observed on ICC 506EB, followed by C 235, and ICCV 10 across Bt concentrations. Leaf feeding by the larvae and larval survival and weights decreased with an increase in Bt concentration. However, rate of decrease in leaf feeding and larval survival and weights with an increase in Bt concentration was greater on L 550 and ICCV 10 than on the resistant check, ICC 506EB, suggesting that factors in the resistant genotypes, particularly the acid exudates, resulted in lower levels of biological activity of Bt possibly because of antifeedant effects of the acid exudates. Antifeedant effects of acid exudates reduced food consumption and hence might reduce the efficacy of Bt sprays on insect‐resistant chickpea genotypes or Bt‐transgenic chickpeas, although the combined effect of plant resistance based on organic acids, and Bt had a greater effect on survival and development of H. armigera than Bt alone.     

Characterization of the Autophagy Marker Protein Atg8 Reveals Atypical Features of Autophagy in Plasmodium falciparum

Conventional autophagy is a lysosome-dependent degradation process that has crucial homeostatic and regulatory functions in eukaryotic organisms. As malaria parasites must dispose a number of self and host cellular contents, we investigated if autophagy in malaria parasites is similar to the conventional autophagy. Genome wide analysis revealed a partial autophagy repertoire in Plasmodium, as homologs for only 15 of the 33 yeast autophagy proteins could be identified, including the autophagy marker Atg8. To gain insights into autophagy in malaria parasites, we investigated Plasmodium falciparum Atg8 (PfAtg8) employing techniques and conditions that are routinely used to study autophagy. Atg8 was similarly expressed and showed punctate localization throughout the parasite in both asexual and sexual stages; it was exclusively found in the pellet fraction as an integral membrane protein, which is in contrast to the yeast or mammalian Atg8 that is distributed among cytosolic and membrane fractions, and suggests for a constitutive autophagy. Starvation, the best known autophagy inducer, decreased PfAtg8 level by almost 3-fold compared to the normally growing parasites. Neither the Atg8-associated puncta nor the Atg8 expression level was significantly altered by treatment of parasites with routinely used autophagy inhibitors (cysteine (E64) and aspartic (pepstatin) protease inhibitors, the kinase inhibitor 3-methyladenine, and the lysosomotropic agent chloroquine), indicating an atypical feature of autophagy. Furthermore, prolonged inhibition of the major food vacuole protease activity by E64 and pepstatin did not cause accumulation of the Atg8-associated puncta in the food vacuole, suggesting that autophagy is primarily not meant for degradative function in malaria parasites. Atg8 showed partial colocalization with the apicoplast; doxycycline treatment, which disrupts apicoplast, did not affect Atg8 localization, suggesting a role, but not exclusive, in apicoplast biogenesis. Collectively, our results reveal several atypical features of autophagy in malaria parasites, which may be largely associated with non-degradative processes.     

Hormonal imbalance and disturbances in carbohydrate metabolism associated with chronic feeding of high sucrose low magnesium diet in weanling male wistar rats

This study was designed to determine chronic effect of high sucrose low magnesium (HSLM) diet in weanling rats on plasma thyroid profile, catecholamines and activities of key hepatic glycolytic, and gluconeogenic enzymes. Compared to control diet fed group, significantly elevated levels of plasma triiodothyronine, tetraiodothyronine, catecholamines (epinephrine, norepinephrine, and dopamine) and activity of hepatic glycolytic (hexokinase and glucokinase), and gluconeogenic (glucose-6-phosphatase) enzymes were observed in high sucrose and low magnesium fed groups. However, HSLM diet had an additive effect on all these three parameters. The study thus, assumes significance as it shows that hormonal imbalance and disorders in carbohydrate metabolism at an early stage of development can be due to dietary modification or due to deficiency of key element magnesium.     

Safety and toxicological evaluation of Rhizopora mucronata (a mangrove from Vellar estuary,India): assessment of mutagenicity,genotoxicity and in vivo acute toxicity

The present was carried out to evaluate the toxicity of methanolic leaf extract of Rhizophora mucronata (MERM) under in vivo and in vitro conditions. Mutagenicity of MERM (up to 4,000 μg/plate) evaluated by Salmonella/microsome assay (TA98, TA100, TA1535 and TA1538 strains), with or without metabolic activation showed no mutagenic effect in any of the tester strain. Evaluation of genotoxicity (comet assay) and cytotoxicity in PBMC revealed that MERM showed no significant difference in comet tail moment (TM) and tail scores and cytotoxicity up to 24 h respectively. In acute toxicity studies, oral administration of single doses of MERM (250–2,000 mg/kg) in Wistar rats produced neither mortality nor any noticeable changes in behavior. Hematological and biochemical parameters showed no difference, except for a significant increase in ALT and AST at the highest dose. Histopathological findings revealed hepatotoxicity and neurotoxicity at highest dose of extract. In subacute toxicity studies administration of MERM (1,000 mg/kg) for 28 consecutive days neither altered the body weight gain nor behavioral parameters. No significant change was observed in the hematological and biochemical parameters analyzed. Histopathological examination showed normal architecture suggesting no morphological disturbances. Collectively, these data demonstrate that consumption of MERM for various medicinal purpose is safe.     

Purification and partial characterization of novel penicillin V acylase from Acinetobacter sp. AP24 isolated from Loktak Lake,an Indo-Burma biodiversity hotspot

Members of the bacterial genus Acinetobacter have attracted great attention over the past few decades, on account of their various biotechnological applications and clinical implications. In this study, we are reporting the first experimental penicillin V acylase (PVA) activity from this genus. Penicillin acylases are pharmaceutically important enzymes widely used in the synthesis of semisynthetic beta-lactam antibiotics. The bacterium, identified as Acinetobacter sp. AP24, was isolated from the water of Loktak Lake (Manipur, India), an Indo-Burma biodiversity hotspot. PVA production was increased threefold in an optimized medium with 0.2% sodium glutamate and 1% glucose as nitrogen and carbon sources respectively, after 24 hr of fermentation at 28°C and pH 7.0 with shaking at 180 rpm. The enzyme was purified to homogeneity by cation-exchange chromatography using SP-sepharose resin. The PVA is a homotetramer with subunit molecular mass of 34 kD. The enzyme was highly specific toward penicillin V with optimal hydrolytic activity at 40°C and pH 7.5. The enzyme was stable from pH 5.0 to 9.0 at 25 °C for 2 hr. The enzyme retained 75% activity after 1 hr of incubation at 40°C at pH 7.5.     

Production,Purification and Stability Studies on Nattokinase: A Therapeutic Protein Extracted from Mutant <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> CMSS Isolated from Bovine Milk

Nattokinase (NK) is a potent fibrinolytic enzyme with the potential for fighting against cardiovascular diseases. In this study, UV mutated Pseudomonas aeruginosa CMSS was used for production, purification and to study the stability of the enzyme. The enzyme was subjected to step by step purification by ammonium sulphate precipitation, dialysis, ion-exchange chromatography and gel filtration chromatography. The purified NK showed 91.84 % of clot lysis, comparable to standard streptokinase. The stability of the purified enzyme was analysed by different parameters such as pH, temperature, metal ions, surfactants and organic solvents. The molecular weight of the enzyme was determined as 27 kDa by SDS-PAGE and confirmed by fibrin zymography. The enzyme obtained its highest activity at pH 5 and at 45 °C. The present study showed the presence of fibrinolytic enzyme by its specificity. Further analysis of the biochemical properties and the precise mechanism of fibrinolytic enzymes will expand the scope of research for development of therapeutic agents to treat thrombosis.