Stearoyl-CoA desaturase-1 deficiency attenuates obesity and insulin resistance in leptin-resistant obese mice

Obesity and adiposity greatly increase the risk for secondary conditions such as insulin resistance. Mice deficient in the enzyme stearoyl-CoA desaturase-1 (SCD1) are lean and protected from diet-induced obesity and insulin resistance. In order to determine the effect of SCD1 deficiency on various mouse models of obesity, we introduced a global deletion of the Scd1 gene into leptin-deficient ob/ob mice, leptin-resistant Agouti (A^y/a) mice, and high-fat diet-fed obese (DIO) mice. SCD1 deficiency lowered body weight, adiposity, hepatic lipid accumulation, and hepatic lipogenic gene expression in all three mouse models. However, glucose tolerance, insulin, and leptin sensitivity were improved by SCD1 deficiency only in A^y/a and DIO mice, but not ob/ob mice. These data uncouple the effects of SCD1 deficiency on weight loss from those on insulin sensitivity and suggest a beneficial effect of SCD1 inhibition on insulin sensitivity in obese mice that express a functional leptin gene.     

Rapid quantification of DNA libraries for next-generation sequencing

The next-generation DNA sequencing workflows require an accurate quantification of the DNA molecules to be sequenced which assures optimal performance of the instrument. Here, we demonstrate the use of qPCR for quantification of DNA libraries used in next-generation sequencing. In addition, we find that qPCR quantification may allow improvements to current NGS workflows, including reducing the amount of library DNA required, increasing the accuracy in quantifying amplifiable DNA, and avoiding amplification bias by reducing or eliminating the need to amplify DNA before sequencing.     

DNA-based Fish Species Identification Protocol

We have developed a fast, simple, and accurate DNA-based screening method to identify the fish species present in fresh and processed seafood samples. This versatile method employs PCR amplification of genomic DNA extracted from fish samples, followed by restriction fragment length polymorphism (RFLP) analysis to generate fragment patterns that can be resolved on the Agilent 2100 Bioanalyzer and matched to the correct species using RFLP pattern matching software.The fish identification method uses a simple, reliable, spin column- based protocol to isolate DNA from fish samples. The samples are treated with proteinase K to release the nucleic acids into solution. DNA is then isolated by suspending the sample in binding buffer and loading onto a micro- spin cup containing a silica- based fiber matrix. The nucleic acids in the sample bind to the fiber matrix. The immobilized nucleic acids are washed to remove contaminants, and total DNA is recovered in a final volume of 100 μl. The isolated DNA is ready for PCR amplification with the provided primers that bind to sequences found in all fish genomes. The PCR products are then digested with three different restriction enzymes and resolved on the Agilent 2100 Bioanalyzer. The fragment lengths produced in the digestion reactions can be used to determine the species of fish from which the DNA sample was prepared, using the RFLP pattern matching software containing a database of experimentally- derived RFLP patterns from commercially relevant fish species.Download video file.^{(106M, mp4)}     

Growth promotion of maize by phosphate-solubilizing bacteria isolated from composts and macrofauna

Five bacterial strains with phosphate-solubilizing ability and other plant growth promoting traits increased the plant biomass (20-40%) by paper towel method. Glasshouse and field experiments were conducted using two efficient strains Serratia marcescens EB 67 and Pseudomonas sp. CDB 35. Increase in plant biomass (dry weight) was 99% with EB 67 and 94% with CDB 35 under glasshouse conditions. Increase in plant biomass at 48 and 96 days after sowing was 66% and 50% with EB 67 and 51% and 18% with CDB 35 under field conditions. Seed treatment with EB 67 and CDB 35 increased the grain yield of field-grown maize by 85% and 64% compared to the uninoculated control. Population of EB 67 and CDB 35 were traced back from the rhizosphere of maize on buffered rock phosphate (RP) medium and both the strains survived up to 96 days after sowing.     

Theoretical evidence that root penetration ability interacts with soil compaction regimes to affect nitrate capture

Background and AimsAlthough root penetration of strong soils has been intensively studied at the scale of individual root axes, interactions between soil physical properties and soil foraging by whole plants are less clear. Here we investigate how variation in the penetration ability of distinct root classes and bulk density profiles common to real-world soils interact to affect soil foraging strategies.MethodsWe utilize the functional–structural plant model ‘OpenSimRoot’ to simulate the growth of maize (Zea mays) root systems with variable penetration ability of axial and lateral roots in soils with (1) uniform bulk density, (2) plow pans and (3) increasing bulk density with depth. We also modify the availability and leaching of nitrate to uncover reciprocal interactions between these factors and the capture of mobile resources.Key ResultsSoils with plow pans and bulk density gradients affected overall size, distribution and carbon costs of the root system. Soils with high bulk density at depth impeded rooting depth and reduced leaching of nitrate, thereby improving the coincidence of nitrogen and root length. While increasing penetration ability of either axial or lateral root classes produced root systems of comparable net length, improved penetration of axial roots increased allocation of root length in deeper soil, thereby amplifying N acquisition and shoot biomass. Although enhanced penetration ability of both root classes was associated with greater root system carbon costs, the benefit to plant fitness from improved soil exploration and resource capture offset these.ConclusionsWhile lateral roots comprise the bulk of root length, axial roots function as a scaffold determining the distribution of these laterals. In soils with high soil strength and leaching, root systems with enhanced penetration ability of axial roots have greater distribution of root length at depth, thereby improving capture of mobile resources.     

Humoral immune response in children with iron-deficiency anaemia.

The humoral immune response (as shown by plasma immunoglobulin concentrations and antibody response to diphtheria and tetanus toxoids) was evaluated in 14 children with iron-deficiency anaemia and in 24 normal controls. Mean concentrations of haemoglobin and serum iron and mean transferrin saturation were significantly lower in children with iron-deficiency anaemia than in controls. Serum immunoglobulin concentrations were within the normal range in both groups. Two weeks after immunisation with diphtheria and tetanus toxoids the concentrations of IgG increased significantly in both groups. Antibody titres in iron-deficient children were similar to those of controls before and after immunisation. The mean T-lymphocyte count was significantly lower in iron-deficient children than that in controls, but the mean B-lymphocyte counts were similar in the two groups. These observations suggest that humoral immunity in children is not affected by iron deficiency and that conventional immunisation programmes would be effective in children with iron-deficiency anaemia.     

Does evolution reduce the body size? A study of the four members of newly evolved nasuta‐albomicans complex of Drosophila

Our long range interracial hybridization experiments between a pair of cross fertile races, Drosophila nasuta (2n = 8) and D.albomicans (2n = 6) have resulted in the evolution of two new karyotypic strains under laboratory conditions, which are named as Cytorace 1 and Cytorace 2. These Cytoraces harbor chromosomes from both parents. Here, we compare the body size of the parental races and newly evolved Cytoraces and the relationship between the body size and fitness. Analysis reveals that the parental races have reduced fertility and are larger in body size than newly evolved Cytoraces. Thus, the newly evolved Cytoraces show reduced body size and better fitness in the course of their evolution. This revised version was published online in July 2006 with corrections to the Cover Date.     

Racial divergence in abdominal bristles among parental races and newly evolved cytoraces of nasuta-albomicans complex of Drosophila.

Cytoraces are the products of interracial hybridization between Drosophila nasuta nasuta and D. nasuta albomicans. These races differ from their parents in the chromosome composition, mating preference, certain fitness phenotypes and also a few morphophenotypic traits. Now, these cytoraces are passing through 330 generations. Racial divergence in the 4th and 5th abdominal bristles among the parental races and the newly evolved cytorace 1 and 2 is reported. The results revealed that the parental races have more number of bristles than newly evolved cytoraces. Thus, these cytoraces are evolved/evolving with reduced abdominal bristle number and better fitness.     

Screening and molecular characterization of Serratia marcescens VITSD2: A strain producing optimum serratiopeptidase

The current work was attempted to isolate and characterize the serratiopeptidase producing Serratia sp. Among the 10 bacterial isolates 7 strains were identified as Serratia sp. Out of 7 strains one showed potent proteolytic activity and selected for further studies. Based on the morphological, biochemical and molecular characterization, the potent isolate （RH03） was identified as Serratia marcescens （GenBank accession number： KC961637） and the strain was designated as Serratia marcescens VITSD2. The production of serratiopeptidase was carried out in trypticase soya broth and the enzyme was partially purified using ammonium sulfate precipitation and dialysis. The specific activity was determined by casein hydrolysis assay and was found to be 12.00, 21.33, and 25.40 units/rag for crude, precipitated and dialysed samples. The molecular weight of the protease was determined by SDS-PAGE and it was found to be 50 kDa. The antibacterial activity of the produced serratiopeptidase showed moderate activity against Pseudomonas aeruginosa MTCC No. 4676 （12 mm） and Escherichia coli MTCC No. 1588 （15 mm）.