Association between N2-fixing bacteria and pearl millet plants: responses, mechanisms and persistence

The responses of different cultivars of Pennisetum americanum to inoculation with Azospirillum and Azotobacter spp. with applications of N fertilizer and FYM were studied in 25 experiments at several locations in India. Increased grain yields of >10% (up to 33%) over the non-inoculated controls were observed in 46% of the experiments. In 2 experiments, continued inoculation for 2 or 3 years increased grain, plant biomass yield and N uptake. Application of combined N and FYM tended to increase yield and total plant N uptake. Inoculation did not increase grain N content in any experimen

Biochemical Changes in Sorghum (Sorghum bicolor L. Moench) Plants Infected with Maize Mosaic Virus*

Biochemical changes in sorghum cultivars naturally infected with maize mosaic virus were investigated. Virus infection reduced plant biomass ranging from 10-53% among different cultivars. Total chlorophyll content in infected leaves was reduced. Reduction in nitrate reductase activity varied from 23-72% in the infected leaves of different cultivars but nitrate reductase activity in the stems of infected plants was significantly higher than in those of healthy plants. The relationship between plant biomass and leaf chlorophyll concentration was positive and that between plant biomass and stem nitrate reductase activity was negative. The relationship between plant biomass and stem N concentration was negative. Concentration of soluble sugars in leaves and stems of infected plants was increased. N concentration in the infected leaves was lower than in the healthy leaves but the N concentration in infected stems was higher. Electrophoretic analysis of soluble leaf proteins revealed the presence of two polypeptides of 21 and 22 kD in the infected but not in the healthy leaves and these were found to be not of viral origin by electro-blot immunoassay

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Enumeration of Nonsymbiotic Nitrogen-fixing bacteria using Enzyme-linked Immunosorbent assay (ELISA).

Serological relationships amongst different genera and also different species of nonsymbiotic N2-fixing bacteria were studied using Enzyme-linked Immunosorbent Assay (ELISA). Azospirillum lipoferum strains ICM 1001 and 4ABL were serologically distinct from strains of A. brasilense & A. amazonense; however, all of 10 A. lipoferum strains showed weak cross reactions, suggesting that these strains shared some common antigens with the A. lipoferum strains. Antisera of A. brasilense strains (SP 7a, SL 33, and SM 6M) did not cross react with 12 strains of A. lipoferum, 4 strains of A. amazonense, nor with 17 strains of A. brasilense tested. An exception was the B 25 strain, which showed the same reaction as that of homologous antigen against SP 7a antiserum. Antisera of azospirilla did not cross react with other genera of N2-fixing bacteria tested using ELISA. Antiserum of Azotobacter chroococcum (ICM 2001) was genus and species specific. Enterobacter cloacae antiserum was genus specific but strains of E. cloacae and E. aerogenes shared some common antigens. The use of the ELISA to enumerate azospirilla in peat inoculants and broth culture and A. chroococcum in broth culture was investigated. A minimum of 10² and 104 cells of Azotobacter and Azospirillum, respectively, are required for a detectable ELISA reaction. Heat killed cells interfere with the ELISA reaction, limiting the use of this technique when the number of bacterial cells is low and all the cells in a sample are killed

Bombesin functionalized gold nanoparticles show cancer receptor specificity: Implications in molecular imaging and therapy

Development of cancer receptor-specific gold nanoparticles will allow efficient targeting/optimum retention of engineered gold nanoparticles within tumors and thus provide synergistic advantages in oncology as it relates to molecular imaging and therapy. Bombesin (BBN) peptides have demonstrated high affinity toward gastrin-releasing peptide (GRP) receptors in vivo that are overexpressed in prostate, breast, and small-cell lung carcinoma. We have synthesized a library of GRP receptor-avid nanoplatforms by conjugating gold nanoparticles (AuNPs) with BBN peptides. Cellular interactions and binding affinities (IC50) of AuNP-BBN conjugates toward GRP receptors on human prostate cancer cells have been investigated in detail. In vivo studies using AuNP-BBN and its radiolabeled surrogate 198AuNP-BBN, exhibiting high binding affinity (IC50 in microgram ranges), provide unequivocal evidence that AuNP-BBN constructs are GRP-receptor-specific showing accumulation with high selectivity in GRP-receptor-rich pancreatic acne in normal mice and also in tumors in prostate-tumor-bearing, severe combined immunodeficient mice. The i.p. mode of delivery has been found to be efficient as AuNP-BBN conjugates showed reduced RES organ uptake with concomitant increase in uptake at tumor targets. The selective uptake of this new generation of GRP-receptor-specific AuNP-BBN peptide analogs has demonstrated realistic clinical potential in molecular imaging via x-ray computed tomography techniques as the contrast numbers in prostate tumor sites are severalfold higher as compared to the pretreatment group (Hounsfield unit = 150)