Dry-reagent gold nanoparticle-based lateral flow biosensor for the simultaneous detection of Vibrio cholerae serogroups O1 and O139

Cholera is a communicable disease caused by consumption of contaminated food and water. This potentially fatal intestinal infection is characterised by profuse secretion of rice watery stool that can rapidly lead to severe dehydration and shock, thus requiring treatment to be given immediately. Epidemic and pandemic cholera are exclusively associated with Vibrio cholerae serogroups O1 and O139. In light of the need for rapid diagnosis of cholera and to prevent spread of outbreaks, we have developed and evaluated a direct one-step lateral flow biosensor for the simultaneous detection of both V. cholerae O1 and O139 serogroups using alkaline peptone water culture. Serogroup specific monoclonal antibodies raised against lipopolysaccharides (LPS) were used to functionalize the colloidal gold nanoparticles for dual detection in the biosensor. The assay is based on immunochromatographic principle where antigen-antibody reaction would result in the accumulation of gold nanoparticles and thus, the appearance of a red line on the strip. The dry-reagent dipstick format of the biosensor ensure user-friendly application, rapid result that can be read with the naked eyes and cold-chain free storage that is well-suited to be performed at resource-limited settings.     

Live non-invasive Shigella dysenteriae 1 strain induces homologous protective immunity in a guinea pig colitis model

A non-invasive live transconjugant Shigella hybrid (LTSHΔstx) strain was constructed from a Shiga toxin gene deleted mutant of Shigella dysenteriae 1 by introducing a plasmid vector pPR1347 that carried a lipopolysaccharide biosynthesis gene (rfb and rfc) of Salmonella typhimurium. In guinea pigs, four successive oral administrations of LTSH Δstx showed complete protection against rectal challenge with wild type S. dysenteriae 1 strain. Exponential increase of the serum IgG and IgA titer against lipopolysaccharide of LTSH Δstx was observed during immunization, peaked on day 28 and remained at that level until day 35 after the initiation of the immunization. In intestinal lavage of the immunized animals, significant increase of IgA titer against lipopolysaccharide of LTSH Δstx was also observed. These data suggested that LTSH Δstx could be a useful candidate to induce protective immunity against S. dysenteriae 1 infection.     

Characterization of cytotoxin-producing Aeromonas caviae (strain HT10) isolated from a sulfur spring in Orissa, India

During a study of microbial diversity, a bacterial strain designated HT10, was isolated from sediment collected from an unexplored sulfur spring at Athamallik, Orissa, India. Various biochemical tests and 16S rDNA sequence analysis revealed that strain HT10 is Aeromonas caviae. The growth temperature of this strain ranged from 12 to 43 degrees C and the optimum temperature was 30 degrees C. The strain HT10 showed cytotoxic and alpha-hemolytic activity. This is the first report on the isolation of Aeromonas caviae from sulfur spring.     

C1q/TNF-related Protein 4 (CTRP4) Is a Unique Secreted Protein with Two Tandem C1q Domains That Functions in the Hypothalamus to Modulate Food Intake and Body Weight

CTRP4 is a unique member of the C1q family, possessing two tandem globular C1q domains. Its physiological function is poorly defined. Here, we show that CTRP4 is an evolutionarily conserved, ∼34-kDa secretory protein expressed in the brain. In human, mouse, and zebrafish brain, CTRP4 expression begins early in development and is widespread in the central nervous system. Neurons, but not astrocytes, express and secrete CTRP4, and secreted proteins form higher-order oligomeric complexes. CTRP4 is also produced by peripheral tissues and circulates in blood. Its serum levels are increased in leptin-deficient obese (ob/ob) mice. Functional studies suggest that CTRP4 acts centrally to modulate energy metabolism. Refeeding following an overnight fast induced the expression of CTRP4 in the hypothalamus. Central administration of recombinant protein suppressed food intake and altered the whole-body energy balance in both chow-fed and high-fat diet-fed mice. Suppression of food intake by CTRP4 is correlated with a decreased expression of orexigenic neuropeptide (Npy and Agrp) genes in the hypothalamus. These results establish CTRP4 as a novel nutrient-responsive central regulator of food intake and energy balance.     

Identification of new QTLs for seed mineral,cysteine, and methionine concentrations in soybean [<Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merr.]

Increased concentrations of important nutrients in edible parts of plants could result in biofortified foods. Soybean [Glycine max (L.) Merr.] is a major legume crop and an important source of certain nutrients, including protein and minerals, in human and animal diets. Understanding the underlying genetic basis of seed composition is crucial to improving seed nutrient composition. In this study we used three soybean recombinant inbred line mapping populations derived from the crosses Williams 82 × DSR-173, Williams 82 × NKS19-90 and Williams 82 × Vinton 81, and constructed a joint linkage map from these populations. Forty quantitative trait loci (QTLs) were detected for 18 traits: seed weight, seed magnesium, sulfur, calcium, manganese, potassium, iron, cobalt, nickel, copper, zinc, selenium, molybdenum, cadmium and arsenic concentrations, total nitrogen:total sulfur (N:S) ratio, cysteine and methionine concentrations. Using the joint linkage map, we detected nine QTLs that were not identified in the individual populations. We identified several candidate genes that might contribute to these traits, including transporters and genes involved in nitrogen and amino acid metabolism. Some strong QTLs had no obvious candidate genes, offering the possibility that subsequent confirmation of these QTLs may result in identification of new genes affecting seed nutrients in soybean. Seed weight and seed mineral concentrations were not highly correlated, suggesting the possibility of improving seed mineral concentrations without significant changes in seed weight. An inverse relationship between N:S ratio and most other minerals suggests the possibility of using N:S ratio as an indirect measure of seed mineral concentration in soybean breeding programs.