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Biomedical subjects

R C Sinha

Publications and source records attributed to R C Sinha.

At least 19 recordsLinked to original sources
PubMed2000

Pre-harvest accumulation of deoxynivalenol in sweet corn ears inoculated with Fusarium graminearum.

Three types of commercial sweet corn hybrids [surgary (su1), shrunken or 'supersweet' (sh2) and surgary enhancer (se1)] were silk channel inoculated in 1996 and 1997 with a macroconidial suspension of Fusarium graminearum to determine how early the mycotoxin deoxynivalenol accumulates in kernels. Disease symptoms rapidly developed on all hybrids and were apparent 4 days after inoculation. Symptoms stabilized by 28 days after inoculation. Toxin levels were greater than 1 microgram/g in kernels as early as 2 weeks after silk emergence and rapidly increased to extremely high levels. Susceptibility in all hybrids decreased as the silk dried out. Deoxynivalenol concentrations were correlated to disease severity. There was some indication that the sh2 genotype was more susceptible than the su1 or se1 genotypes. These results suggest that improvement needs to be made in sweet corn with respect to resistance to gibberella ear rot.

Enzyme-Linked Immunosorbent Assay↗
PubMed1998

Analysis of Fusarium toxins in maize and wheat using thin layer chromatography.

Thin layer chromatography (TLC) methods for identifying and quantifying deoxynivalenol (DON), fumonisin B1 (FB1) and zearalenone in grain samples were compared to immunoassay (ELISA) and high performance liquid chromatography (HPLC) methods to determine the reliability of the less expensive TLC. There was a very good agreement between levels of DON measured by TLC and competitive-direct ELISA, and between levels of fumonisin B1 measured by TLC and HPLC, over a wide range of concentrations. Correlation coefficients (Pearson's) were 0.978, 0.914 and 0.953 for DON in maize, DON in wheat and FB1 in maize respectively. A lower correlation coefficient (r = 0.672) was obtained when zearalenone was quantified by TLC and HPLC. Possible reasons for this are discussed. A cost comparison of the various methods revealed that TLC was the least expensive for sample analysis. It is recommended that researchers choose which analytical method to use based upon individual considerations of cost and precision.

Carboxylic Acids↗
PubMed1993

Replication and encapsidation of the viroid-like satellite RNA of lucerne transient streak virus are supported in divergent hosts by cocksfoot mottle virus and turnip rosette virus.

Cocksfoot mottle sobemovirus supports replication and encapsidation of the viroid-like satellite RNA (sat-RNA) of lucerne transient streak virus (LTSV) in two monocotyledonous species, Triticum aestivum and Dactylis glomerata. Additionally, LTSV sat-RNA replicates effectively in the presence of turnip rosette sobemovirus in Brassica rapa, Raphanus raphanistrum and Sinapsis arvensis, but not in Thlaspi arvense or Nicotiana bigelovii, indicating that host species markedly influence this interaction. Previous reports of the association between LTSV sat-RNA and helper sobemoviruses were limited to dicotyledonous hosts. Our results demonstrate that the biological interaction between these two entities spans divergent dicotyledonous and monocotyledonous species.

Defective Viruses↗
PubMed1990

Sequence of the 3'-terminal region of turnip mosaic virus RNA and the capsid protein gene.

A sequence of 1801 nucleotides originating from the 3' end region of turnip mosaic virus (TuMV) RNA was cloned using the polymerase chain reaction and found to contain one long open reading frame (ORF). The amino acid sequence of three different regions of the isolated TuMV capsid protein (including the NH2 terminus) was determined and these partial sequences were found in the translation product predicted to be encoded by the large ORF. The data suggested that the TuMV capsid protein was a product arising from the maturation of a larger polyprotein, as observed for other potyviruses. Furthermore, the putative cleavage site corresponded to a glutamine-alanine dipeptide, a site commonly used in plant virus polyprotein processing. The capsid protein cistron was composed of 864 nucleotides and corresponded to a region encoding 288 amino acids with a calculated Mr of 33,186; the adjacent 3' non-coding region was 667 nucleotides long. The deduced amino acid sequence of the TuMV capsid protein is closely related to other potyvirus capsid proteins, with most of the variation being found within the NH2-terminal region.

Amino Acid Sequence↗
PubMed1989

Seasonal changes in energy reserves in the common frog, Rana tigrina.

Liver glycogen and lipid, ovarian glycogen, and lipid index were used as criteria to elucidate energy changes associated with reproduction and biphasic pattern of dormancy (summer and winter) in the female forg, Rana tigrina. Liver glycogen showed 2 peaks; the ovarian glycogen showed reciprocal relationship with that of liver. The liver lipid and glycogen showed parallel trend.

Animals↗
PubMed1985

Enzymatic activities in cell fractions of mycoplasmalike organisms purified from aster yellows-infected plants.

Mycoplasmalike organisms (MLOs), purified from aster yellows-infected plants were osmotically lysed, and the membranes were separated from the cytoplasmic fraction through differential centrifugation. Electron microscopic examinations of sections of the purified MLOs and the isolated membranes showed pleomorphic bodies and unit membranous empty vesicles, respectively. Cell fractions were tested for NADH oxidase, NADPH oxidase, ATPase, RNase, DNase, and p-nitrophenyl phosphatase activity. NADH oxidase and ATPase were confined to the membrane fraction and NADPH oxidase to the cytoplasmic fraction of the MLOs. para-Nitrophenyl phosphatase, RNase, and DNase activities were detected in both membrane and cytoplasmic fractions, but p-nitrophenyl phosphatase and RNase appeared to be associated with membranes and DNase with the cytoplasmic fraction. Glucose-6-phosphate dehydrogenase was found in the cytoplasmic fraction of the MLO cells. Our findings on the distribution of enzymes in MLO cells and cell fractions are the first basic documentation on nonhelical, nonculturable microbes parasitic to plants.

4-Nitrophenylphosphatase↗
PubMed1984

Application of immunodiffusion to the identification of Rhizobium meliloti strains competing for nodulation on Medicago sativa.

The immunodiffusion technique was successfully used to unambiguously recognize four strains of Rhizobium meliloti in a study of competition for nodulation with Medicago sativa cv. Apollo inoculated with two-, three- and four-strain mixtures. The serological reactions of all R. meliloti strains revealed no significant changes following plant passage indicating that the antigens involved in immunodiffusion were stable. R. meliloti 102F70 formed 50% or more of the nodules on M. sativa inoculated with two-, three- and four-strain mixtures. The remaining three strains were less competitive and produced similar proportions of nodules (14-20%) on plants inoculated with three- and four-strain mixtures. Cases of mixed-strain occupancy of nodules involving either two of three strains were detected in a sub-sample of nodules. The data also indicated considerable variation in the proportions of strains in the nodules of individual plants.

Immunodiffusion↗
PubMed1983

Haematological studies on the prewintering and wintering frog, Rana esculenta.

1. A study of the haematology of the frog Rana esculenta including erythrocyte count (RBC), haemoglobin content (Hb), haematocrit (HCT), mean cell volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and erythrocyte size as a function of prewinter and winter was made. 2. The RBC count and Hb were significantly higher in contrast to MCV and MCH values during prewinter in both sexes. 3. The surface area to volume ratio was higher in prewinter whereas the length to width ratio (eccentricity) of the cytosome and nucleus was significantly higher during winter in both sexes. 4. Sexual differences in the erythrocyte count, Hb content and the surface area to volume ratio were also observed. 5. The physiological significance of these observations are reported for Rana esculenta.

Acclimatization↗
PubMed1982

Effect of starvation and refeeding on the scorpion, Buthus tamulus.

1. Scorpions were starved for 1, 4, 8, and 12 days and then subsequently refed until the sixteenth day. The concentrations of glycogen, amino acid, and protein in the liver were determined to evaluate the effect of starvation and refeeding on these biochemical constituents. 2. The concentration of glycogen decreased gradually but significantly with the progressive days of starvation. After refeeding, the concentration increased sharply and attained the normal condition after 4 days of refeeding. 3. The concentrations of amino acids and proteins increased during first few days of starvation and declined thereafter. After refeeding the concentrations of amino acids and proteins increased gradually and attained the normal conditions after 3 and 4 days respectively. 4. The water content of the liver did not show any significant variation with the progressive days of starvation or after refeeding.

Amino Acids↗
PubMed1980

Homologous serological analysis of Rhizobium meliloti strains by immunodiffusion.

The homologous titers of antisera prepared against 24 Rhizobium meliloti strains ranged from 8 to 64 in immunodiffusion tests when intact cells were used as test antigens. The antisera titers against a number of strains were higher when heated or ultrasonicated cell preparations were used as sources of antigens. The minimum concentration of intact cells required to produce a positive reaction varied between strains and the heat treatment of the cells of some strains increased the detectability of surface antigens. Titers of antigens in sonicated preparations of several strains were higher than those of either intact or heated cells. The minimum concentration of antigens detectable for different strains was independent of the antisera titers. Serological reactions of strains using intact cells were categorized in several groups based on the shape, position, and number of precipitin bands formed at different cell densities. The sonicated cell preparations produced additional bands and most strains contained both heat-stable and heat-labile antigens in such preparations. Some of these antigens were similar but not identical to the surface antigens whereas others appeared to be unrelated.

Antigens, Bacterial↗