Phytoplankton and nutrient dynamics of shallow coastal stations at Bay of Bengal,Eastern Indian coast

Phytoplankton dynamics of Eastern Indian coast was studied from surface water for a period of 24 months (April 2005–March 2007) in relation to environmental variables like, temperature, pH, dissolved oxygen, biochemical oxygen demand (BOD), salinity and nutrient contents—including nitrate, phosphate and silicate. Total 43 taxa were recorded during the study period. Phytoplankton density ranged from approximately 350–3,000 cells/ml and showed complete dominance of diatom genera namely, Asterionella japonica in winter and Odontella rhombus in summer. Other frequently occurring diatoms were Coscinodiscus perforatus, Actinocyclus normanii f. subsala, Thalassiothrix fraunfeldii, Ditylum brightwelli, Stephanodiscus hantzschoides, Cyclotella meneghiniana, Thalassionema nitzschoides etc. Seasonal changes in abundance and diversity of phytoplankton significantly differed showing maximum diversity in autumn with high diversity index (2.76-Oct, 05) and minimum in winter (0.326-January, 06). The species evenness varied from 0.137 (January 06) to 0.991 (August 06), which signifies minimum variation in percentage contribution of individual species to total phytoplankton population in monsoon and maximum in winter. Correlation studies of total cell count to physicochemical variables indicated significant positive relation with dissolved oxygen, salinity and pH but negative relation with nitrate, silicate and BOD of the water body. Multivariate procedures like ordination by principal component analysis and multi dimensional scaling of phytoplankton population based on their occurrence data and magnitude of abundance indicated that some genera (Biddulphia heteroceros, B. dubia, Odontella aurita, Gyrosigma acuminatum, Coscinodiscus granii, Paralia sulcata, etc.) have specific preference for water temperature and salinity and flourished maximally in particular season(s). While other genera (A. japonica, C. meneghiniana, C. perforatus, D. brightwelli, S. hantzschoides, etc.) appeared in wide range of temperature and salinity gradient.     

Insulin decreases the secretion of apoB-100 from hepatic HepG2 cells but does not decrease the secretion of apoB-48 from intestinal CaCo-2 cells

We compared the acute effect of insulin on the human colonic intestinal epithelial cell line CaCo-2 and the transformed human hepatic cell line HepG2. Over 24 h, 100 nM and 10 µM insulin significantly inhibited the secretion of apolipoprotein (apo) B-100 from HepG2 cells to 63 and 49% of control, respectively. Insulin had no effect on the secretion of apoB-48 from CaCo-2 cells. There was no effect of insulin on the cholesterol ester or free cholesterol concentrations in HepG2 or CaCo-2 cells. HepG2 and CaCo-2 cells bound insulin with high affinity, leading to similar stimulation of insulin receptor protein tyrosine kinase activation. Protein kinase C or mitogen-activated protein kinase activity in the presence or absence of insulin was not correlated with apoB-48 production in CaCo-2 cells. Therefore, insulin acutely decreases the secretion of apoB-100 in hepatic HepG2 cells, but does not acutely modulate the production or secretion of apoB-48 from CaCo-2 intestinal cells.     

Removing the threat of diclofenac to critically endangered Asian vultures

Veterinary use of the nonsteroidal anti-inflammatory (NSAID) drug diclofenac in South Asia has resulted in the collapse of populations of three vulture species of the genusGyps to the most severe category of global extinction risk. Vultures are exposed to diclofenac when scavenging on livestock treated with the drug shortly before death. Diclofenac causes kidney damage, increased serum uric acid concentrations, visceral gout, and death. Concern about this issue led the Indian Government to announce its intention to ban the veterinary use of diclofenac by September 2005. Implementation of a ban is still in progress late in 2005, and to facilitate this we sought potential alternative NSAIDs by obtaining information from captive bird collections worldwide. We found that the NSAID meloxicam had been administered to 35 captiveGyps vultures with no apparent ill effects. We then undertook a phased programme of safety testing of meloxicam on the African white-backed vultureGyps africanus, which we had previously established to be as susceptible to diclofenac poisoning as the endangered AsianGyps vultures. We estimated the likely maximum level of exposure (MLE) of wild vultures and dosed birds by gavage (oral administration) with increasing quantities of the drug until the likely MLE was exceeded in a sample of 40G. africanus. Subsequently, sixG. africanus were fed tissues from cattle which had been treated with a higher than standard veterinary course of meloxicam prior to death. In the final phase, ten Asian vultures of two of the endangered species(Gyps bengalensis,Gyps indicus) were dosed with meloxicam by gavage; five of them at more than the likely MLE dosage. All meloxicam-treated birds survived all treatments, and none suffered any obvious clinical effects. Serum uric acid concentrations remained within the normal limits throughout, and were significantly lower than those from birds treated with diclofenac in other studies. We conclude that meloxicam is of low toxicity toGyps vultures and that its use in place of diclofenac would reduce vulture mortality substantially in the Indian subcontinent. Meloxicam is already available for veterinary use in India.     

MsrA Efflux Pump Inhibitory Activity of Piper cubeba L.f. and its Phytoconstituents against Staphylococcus aureus RN4220

MsrA, an efflux pump belonging to ATP‐binding cassette (ABC) transporter family that conferred resistance to macrolides, was detected in Staphylococcus aureus strains. Herein, we report the isolation of phytoconstituents from Piper cubeba fruit methanol extract and investigated their efflux pump inhibitory potential against S. aureus MsrA pump. Four isolated compounds, viz. pellitorine, sesamin, piperic acid and tetrahydropiperine studied in combination with erythromycin in S. aureus RN4220, exhibited 2–8‐fold reduction in minimum inhibitory concentration (MIC) of erythromycin. Pellitorine and sesamin decreased MIC of erythromycin by 8‐fold. The real‐time fluorometry‐based efflux and accumulation studies of ethidium bromide (EtBr) on S. aureus RN4220 in the presence of these compounds showed reduced efflux and enhanced uptake, thus indicating inhibition of the efflux pump. Pellitorine showed significant post‐antibiotic effect of erythromycin. The results revealed that the primary mechanism of action of these compounds involves steady ATP production impairment.     

Doubled Haploid Production Using an Improved Anther Culture Protocol for Sorghum [<i>Sorghum bicolor</i> (L.) Moench]

Sorghum [Sorghum bicolor (L.) Moench] can benefit from accelerated breeding and release of improved varieties through doubled haploid technology. The technology has been used in speeding up the breeding of other major cereals such as wheat, maize and rice, for which generally widely applied optimised protocols exist. A reproducible protocol for the crop, that can overcome genotype dependency and other species-specific challenges such as phenolic exudation is however lacking. This study aimed at sorghum doubled haploids production thereby contributing to the development of an improved protocol. From the 28 hybrid genotypes, both F₁ registered- and experimental hybrids involved, this study successfully produced haploids from five genotypes and subsequently, four confirmed doubled-haploid lines on W14mf medium or its modification with 1.0 gl⁻¹ L-proline, 1.0 gl⁻¹ L-asparagine and 1.0 gl⁻¹ KH₂PO₄. Medium 190-2Cu was used for regeneration and rooting, which occurred successfully, if the calli were transferred on to it less than 7 days after induction, and temperature was maintained at 25˚C under light condition. Genotype dependency was not wholly overcome; however, sorghum’s high tillering ability and abiotic stress tolerance were observed to contribute to attainment of haploid plantlets. Spontaneous diploids producing seeds at rates of upto 80.5% were obtained, therefore eliminating the need for colchicine duplication.     

Association genetics of the parameters related to nitrogen use efficiency in Brassica juncea L.

Key message

Genome wide association studies allowed prediction of 17 candidate genes for association with nitrogen use efficiency. Novel information obtained may provide better understanding of genomic controls underlying germplasm variations for this trait in Indian mustard.

Abstract

Nitrogen use efficiency (NUE) of Indian mustard (Brassica juncea (L.) Czern & Coss.) is low and most breeding efforts to combine NUE with crop performance have not succeeded. Underlying genetics also remain unexplored. We tested 92 SNP-genotyped inbred lines for yield component traits, N uptake efficiency (NUPEFF), nitrogen utilization efficiency (NUTEFF), nitrogen harvest index (NHI) and NUE for two years at two nitrogen doses (N_o without added N and N₁₀₀ added @100 kg/ha). Genotypes IC-2489-88, M-633, MCP-632, HUJM 1080, GR-325 and DJ-65 recorded high NUE at low N. These also showed improved crop performance under high N. One determinate mustard genotype DJ-113 DT-3 revealed maximum NUTEFF. Genome wide association studies (GWAS) facilitated recognition of 17 quantitative trait loci (QTLs). Environment specificity was high. B-genome chromosomes (B02, B03, B05, B07 and B08) harbored many useful loci. We also used regional association mapping (RAM) to supplement results from GWAS. Annotation of the genomic regions around peak SNPs helped to predict several gene candidates for root architecture, N uptake, assimilation and remobilization. CAT9 (At1g05940) was consistently envisaged for both NUE and NUPEFF. Major N transporter genes, NRT1.8 and NRT3.1 were predicted for explaining variation for NUTEFF and NUPEFF, respectively. Most significant amino acid transporter gene, AAP1 appeared associated with NUE under limited N conditions. All these candidates were predicted in the regions of high linkage disequilibrium. Sequence information of the predicted candidate genes will permit development of molecular markers to aid breeding for high NUE.

     

RUNX1T1, a potential prognostic marker in breast cancer,is co-ordinately expressed with ERα, and regulated by estrogen receptor signalling in breast cancer cells

Molecular Biology Reports - RUNX1T1 is extensively studied in the context of AML1-RUNX1T1 fusion protein in acute myeloid leukemia. Little is known about the function of RUNX1T1 itself, although...