Studies on cellular adhesion of Xenopus laevis melanophores: modulation of cell-cell and cell-substratum adhesion in vitro by endogenous Xenopus galactoside-binding lectin

We have investigated cell-cell and cell-substratum adhesion of Xenopus laevis neural crest cells at various stages of melanophore differentiation. Single-cell suspensions were obtained by trypsinization and aggregated in a cell-cell adhesion assay. Unpigmented cells did not adhere while the rate of adhesion of melanophores correlated with the degree of melanization. Melanophore cell-cell adhesion decreased significantly in the presence of beta-galactosidase, which suggests that cell-surface galactose is involved. Beta-galactoside-binding lectin has been isolated and purified from embryos at the stage of neural crest migration. When added to aggregating cells smaller, looser clusters formed compared to controls. When lectin was added to cells in stationary culture to test cell-substratum adhesion, melanophores spread more smoothly and formed more regular spacing patterns. These results suggest that this lectin can modulate receptors used in cell-cell and cell-substratum adhesion of melanophores.     

Development and Validation of Real-Time PCR for Rapid Detection of Mecistocirrus digitatus

Hematophagous activity of Mecistocirrus digitatus, which causes substantial blood and weight loss in large ruminants, is an emerging challenge due to the economic loss it brings to the livestock industry. Infected animals are treated with anthelmintic drugs, based on the identification of helminth species and the severity of infection; however, traditional methods such as microscopic identification and the counting of eggs for diagnosis and determination of level of infection are laborious, cumbersome and unreliable. To facilitate the detection of this parasite, a SYBR green-based real-time PCR was standardized and validated for the detection of M. digitatus infection in cattle and buffaloes. Oligonucleotides were designed to amplify partial Internal Transcribed Spacer (ITS)-1 sequence of M. digitatus. The specificity of the primers was confirmed by non-amplification of DNA extracted from other commonly occurring gastrointestinal nematodes in ruminants. Plasmids were ligated with partial ITS-1 sequence of M. digitatus, serially diluted (hundred fold) and used as standards in the real-time PCR assay. The quantification cycle (Cq) values were plotted against the standard DNA concentration to produce a standard curve. The assay was sensitive enough to detect one plasmid containing the M. digitatus DNA. Clinical application of this assay was validated by testing the DNA extracted from the faeces of naturally infected cattle (n = 40) and buffaloes (n = 25). The results were compared with our standard curve to calculate the quantity of M. digitatus in each faecal sample. The Cq value of the assay depicted a strong linear relationship with faecal DNA content, with a regression coefficient of 0.984 and efficiency of 99%. This assay has noteworthy advantages over the conventional methods of diagnosis because it is more specific, sensitive and reliable.     

Host plant utilization by butterfly larvae in the Andaman and Nicobar Islands (Indian Ocean)

The larval food plants of the butterflies of the Andaman and Nicobar islands have not been studied, although the butterfly fauna per se is fairly well known. For the first time we report the food plants of the larvae of 120 species of butterflies from these islands on the basis of laboratory rearing and field studies. This information is essential for the formulation of management programmes for butterfly conservation on these islands which are known to harbour critical swallowtail and (possibly) danaine faunas.     

Fatty acid amide hydrolase is a key regulator of endocannabinoid-induced myocardial tissue injury

Previous studies have suggested that increased levels of endocannabinoids in various cardiovascular disorders (e.g., various forms of shock, cardiomyopathies, atherosclerosis) through the activation of CB(1) cannabinoid receptors may promote cardiovascular dysfunction and tissue injury. We have investigated the role of the main endocannabinoid anandamide-metabolizing enzyme (fatty acid amide hydrolase; FAAH) in myocardial injury induced by an important chemotherapeutic drug, doxorubicin (DOX; known for its cardiotoxicity mediated by increased reactive oxygen and nitrogen species generation), using well-established acute and chronic cardiomyopathy models in mice. The DOX-induced myocardial oxidative/nitrative stress (increased 4-hydroxynonenal, protein carbonyl, and nitrotyrosine levels and decreased glutathione content) correlated with multiple cell death markers, which were enhanced in FAAH knockout mice exhibiting significantly increased DOX-induced mortality and cardiac dysfunction compared to their wild type. The effects of DOX in FAAH knockouts were attenuated by CB(1) receptor antagonists. Furthermore, anandamide induced enhanced cell death in human cardiomyocytes pretreated with FAAH inhibitor and enhanced sensitivity to ROS generation in inflammatory cells of FAAH knockouts. These results suggest that in pathological conditions associated with acute oxidative/nitrative stress FAAH plays a key role in controlling the tissue injury that is, at least in part, mediated by the activation of CB(1) receptors by endocannabinoids.     

A semi-synthetic diet for rearing Dipha aphidivora (Lepidoptera: Pyralidae), a promising predator of woolly aphid in sugarcane

Dipha aphidivora (Meyrick), a lepidopteran predator of sugarcane woolly aphid (SWA) Ceratovacuna lanigera Zehntner was successfully reared for three successive generations, for the first time on a freeze-dried beef liver-based larval semi-synthetic diet. We compared biological parameters viz., larval survival, adult weight, pre-and oviposition period, fertility, fecundity and female longevity of D. aphidivora reared on the semi-synthetic diet with the predators reared on SWA. Development time of larvae reared from first instar to pupation was 20.6 days on the semi-synthetic diet and 12 days on SWA, while survival of the larvae to adults was 61.8 and 91.8% on larval semi-synthetic diet and SWA, respectively. Fecundity recorded from semi-synthetic diet (41 eggs/female) was significantly less than those produced on SWA (58 eggs/female). However, fertility and longevity of the predators reared on SWA and semi-synthetic diet did not differ significantly. The study revealed the possibility of rearing D. aphidivora larvae using synthetic diet.     

Designing chitosan-dextran sulfate nanoparticles using charge ratios

The purpose of this study was to examine the effect of charge ratio on the formation and properties of the chitosan (CS)-dextran sulfate (DS) nanoparticles developed for the delivery of water-soluble small and large molecules, including proteins. Rhodamine 6G (R6G) and bovine serum albumin (BSA) were chosen as model molecules. CS-DS nanoparticles were formulated by a complex coacervation process under mild conditions. The influence of formulation and process variables, including the charge ratio of the 2 ionic polymers, on particle size, zeta potential, and nanoparticle entrapment of R6G and BSA was studied. The in vitro release of R6G and BSA was also evaluated, and the integrity of BSA in the release fraction was assessed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Depending on the concentration and charge ratio of DS and CS, nanoparticles with varied size (>or=244 nm) and zeta potential (-47.1-60 mV) were obtained. High entrapment efficiency (98%) was achieved for both R6G and BSA when the charge ratio of the 2 ionic polymers was greater than 1.12. The release of both R6G and BSA from nanoparticles was based on the ion-exchange mechanism. BSA showed much slower continuous release for up to 7 days while still maintaining its integrity for an extended period. The CS-DS nanoparticles developed based on the modulation of charge ratio show promise as a system for controlled delivery of both small and large molecules, including proteins.