High Performance Thin Layer Chromatography (HPTLC) profile of an insecticidal compound of <Emphasis Type="Italic">Trochus radiatus</Emphasis> and assessment of mucus-associated bacterial extracts

The current study is based on the screening of novel insecticides from new sources that have not being exploited hitherto. The major objectives of this research work were to extract marine molluscs, Lambis lambis, Trochus radiatus and Chicoreus ramosus, from Tuticorin coastal waters using different solvents to test their insecticidal properties and partially purify the active components. The ethyl acetate extracts of L. lambis and T. radiatus showed 100% mortality of Sitophilus oryzae, at a concentration of 200 μg ml⁻¹. The LC₅₀ values for ethyl acetate extracts of L. lambis, T. radiatus and C. ramosus were found to be 67.08, 348.86 and 571.42 μg ml⁻¹, respectively. With regard to bacterial metabolites, at a concentration of 200 μg ml⁻¹ the ethyl acetate extract of A3 was able to elicit an activity of 40% and that of strain A1 – 20%. The LC₅₀ values of the bacterial metabolites were also investigated. Upon chromatographic separation of active ethyl acetate extracts of T. radiatus, the 100% methanol column-purified fraction was found to have an activity of 30% at a concentration of 10 μg against S. oryzae. The purity of the partially pure active compound was observed to be 72.78% on analysis with high pressure thin layer chromatography.     

Ultra‐long‐acting recombinant insulin for the treatment of diabetes mellitus in dogs

BackgroundFor the treatment of diabetes mellitus (DM) in dogs, novel insulins with decreased injection frequency while maintaining safety and efficacy are desirable. Insulin fused with immunoglobulin‐fragment‐crystallizable (Fc) has an ultra‐long plasma half‐life because it recycles through cells, protected from proteolysis.HypothesisGlycemic control can be achieved in diabetic dogs with a recombinant fusion protein of a synthetic insulin and canine Fc (AKS‐218d) administered subcutaneously once‐weekly.AnimalsFive client‐owned dogs with naturally occurring DM.MethodsProspective clinical trial in dogs with DM that were recruited from the UC Davis Veterinary Teaching Hospital and local veterinary clinics. Dogs previously controlled using intermediate‐acting insulin q12h were transitioned to once‐weekly injections of a preliminary construct identified as AKS‐218d. The dose of AKS‐218d was titrated weekly for 8 weeks based on clinical response and continuous interstitial glucose monitoring. Clinical signs, body weight, serum fructosamine concentrations, and mean interstitial glucose concentrations (IG) over the preceding week were compared between baseline (before AKS‐218d) and during the last week of treatment. Data were compared using nonparametric paired tests.ResultsOnce‐weekly AKS‐218d, compared to baseline twice‐daily insulin therapy, resulted in no significant changes in clinical signs, median (range) body weight (+0.4 kg [−0.5‐1.1]; P = .6), fructosamine concentration (−75 mmol/L [−215 to +126]; P = .4), or mean IG (+81 mg/dL [−282 to +144]; P = .8). No adverse reactions were reported.ConclusionControl of clinical signs, body weight, and maintenance of glycemia was achieved with this once‐weekly novel insulin construct in 4 of 5 dogs.     

Genetic analysis of yield and quantitative traits in pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> L. Millsp.)

Basic information on genetics and inheritance of quantitative characters, which is necessary to develop future breeding programme, is not widely studied in pigeonpea. Hence, present study was conducted among 5 generations in four pigeonpea crosses to know significance of additive-dominance model, gene action involved in inheritance of quantitative characters, heritability and genetic advance. “Scaling” and “joint scaling test” was significant for most characters indicating that additive-dominance model alone is not enough to explain the inheritance of a character. Though additive variance was more, dominance variance also played important role for most of the traits. Positive and negative alleles were found to be distributed between parents. Additive gene effect (d) was significant for pods per plant and seeds per pod whereas dominance gene effect (h) was more predominant among pod yield and seed yield. Dominance × Dominance inter-allelic interactions (l) was more important than Additive × Additive type (i) for most of the traits studied which could be exploited by selecting individuals based on their performance in recurrent selection. Complementary gene action was observed among many traits with few exhibiting duplicate gene action. Heritability and genetic advance was high indicating the effectiveness of selection. Since dominance effects is also present along with additive effects selection could be practised in later generations to identify high yielding genotypes.     

Biochemistry of TBT-Degrading Marine Pseudomonads Isolated from Indian Coastal Waters

Tributyltin (TBT) is a very effective biocide and an active ingredient in antifouling paints. Screening along the Indian coast yielded 49 bacterial isolates capable of TBT assimilation. The screening was done based on the ability of bacteria to grow in mineral salt medium (MSM) containing TBT as the sole source of carbon. All the isolates produced exopolysaccharides (biosurfactants) in the medium which aid in emulsification and thus ease bioavailability of TBT. Five isolates were identified as potent TBT degraders (namely, Pseudomonas pseudoalcaligenes, Pseudomonas stutzeri, Pseudomonas mendocina, Pseudomonas putida, and Pseudomonas balearica) based on their biomass production in MSM containing TBT as the sole source of carbon. In addition to evaluating the potential of individual bacterial strains, the study also focused on using a consortium of bacteria to explore their synergistic effect when grown on TBT. Further tests like growth profile, rhamnolipid secretion profile, extracellular protein secretion profile, and detection of siderophores were performed on these isolates when grown in MSM supplemented with 2 mM TBT concentration. Emulsification activity of the crude extracellular polysaccharides against kerosene was evaluated. It can be therefore inferred that TBT degradation by these marine pseudomonads is a two-step process: (a) dispersion of TBT in the aqueous phase and (b) tin–carbon bond cleavage by siderophores affecting debutylation of TBT. The consortium of bacteria may be effective in the treatment of TBT-contaminated waste water in dry docks.     

Hypoglycemic effect of Mucuna pruriens seed extract on normal and streptozotocin-diabetic rats

The hypoglycemic effect of the aqueous extract of the seeds of Mucuna pruriens was investigated in normal, glucose load conditions and streptozotocin (STZ)-induced diabetic rats. In normal rats, the aqueous extract of the seeds of Mucuna pririens (100 and 200 mg/kg body weight) significantly (P<0.001) reduced the blood glucose levels after an oral glucose load from 127.5+/-3.2 to 75.6+/-4.8 mg% 2 h after oral administration of seed extract. It also significantly lowered the blood glucose in STZ diabetic rats from 240.5+/-7.2 to 90.6+/-5.6 mg% after 21 days of daily oral administration of the extract (P<0.001). Thus, this study shows that M. pruriens has an anti-hyperglycemic action and it could be a source of hypoglycemic compounds.     

Development of chitosan conjugated DNA vaccine against nodavirus in Macrobrachium rosenbergii (De Man, 1879)

The protective efficacy of a DNA construct containing extra small virus antisense (XSVAS) gene of nodavirus encapsulated with chitosan nanoparticles (NPs) was investigated in giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879). The delivery was carried out using oral and immersion methods. A plasmid concentration of 100 ng μL^?1 when conjugated with chitosan NPs was found to be more effective in increasing the survivability of the infected prawn. The particle mean size, zeta potential and loading efficiency percentage were 297 nm, 27 mV and 85%, respectively. The ability of the chitosan to form a complex with the plasmid was studied by agarose gel electrophoresis. The NPs were characterized by atomic force microscopy (AFM). Persistence study showed the presence of the DNA construct up to 30th day post‐treatment. The oral treatment was found to be better than the immersion treatment for delivery of the chitosan‐conjugated DNA construct. This is probably the first report on the delivery of nanoconjugated DNA construct in M. rosenbergii, against nodavirus.     

Estimation of genetic diversity among 34 genotypes in the genus <Emphasis Type="Italic">Cajanus</Emphasis> with contrasting host response to the pod borer and its allied pests

The genetic divergence among 34 genotypes belonging to 12 species of genus Cajanus were carried out using plant pest interaction and DNA marker analysis. Principal component analysis based on average percentage of pod damage caused by pod borer, plume moth, and blue butterfly in the field conditions, and growth of their larva and pupa on an artificial diet in vitro dispersed these genotypes into four coordinates evincing high genetic divergence as expected. DNA marker analysis using 11 pairs of SSR and nine ISSR primers showed higher polymorphism at the species level, and these primers exhibited variation with regard to average band informativeness, resolving power, and PIC value. No single primer was able to distinguish between all the 34 genotypes of Cajanus but nine species specific amplified fragments were generated by five ISSR primers. The pairwise Jaccard’s similarity coefficient and Nei’s genetic distance values revealed a higher level of inter-specific genetic variation in the genus Cajanus. The clustering of genotypes based on Jaccard’s similarity coefficient vis-a-vis Nei’s genetic distance agreed with the sectional classification of the genus Cajanus. Seven cultivars of C. cajan and the genotypes of their wild progenitor C. cajanifolius remained in one cluster, whereas accessions of C. platycarpus and C. scarabaeoides were out grouped. The rest of the genotypes belonging to nine species of Cajanus formed another cluster. The principal coordinate analysis also supported this clustering pattern. Moreover, these findings have good many implications for future breeding endeavors aimed at the introgression of pod borer resistance alleles.     

Marker‐assisted backcross breeding for improvement of drought tolerance in bread wheat (Triticum aestivum L. em Thell)

Drought stress is presently a major productivity limiting factor in wheat. This study developed five wheat lines with inbuilt tolerance to drought stress using marker‐assisted backcross breeding (MABB) approach employing three linked quantitative trait loci (QTLs) in an initial population of 516 BC₁F₁ plants. The high‐yielding wheat cultivar ‘HD2733’ grown over last few years extensively in the eastern plains of India is largely sensitive to drought and is used as the recurrent parent. ‘HI1500’ released for water‐limiting conditions and carrying drought‐tolerant QTLs was used as donor parent. MABB lines were advanced using foreground and background selection, coupled with stringent phenotyping. We identified 29 lines that were homozygous for targeted QTLs in different combinations with background recovery range of 89.2%–95.4%. Further evaluation of selected lines for physiological traits and distinctness, uniformity and stability (DUS) characters under rainfed condition identified five potential varieties for national varietal evaluation programme in the zone. The report is first of its kind in implementing known QTLs for the development of drought‐tolerant wheat lines through MABB approach.     

Ammonia-oxidizing bacterial and archaeal communities in tropical bioaugmented zero water exchange shrimp production systems

Journal of Soils and Sediments - Ammonia oxidation is an important process in the removal of ammonia generated from feed and metabolic wastes in aquaculture systems. Considering the biogeochemical...