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S Jayachandran

Publications and source records attributed to S Jayachandran.

27 records · Page 2Linked to original sources
PubMed1983

A glycosylated protoxin in killer yeast: models for its structure and maturation.

The type 1 killer phenotype in S. cerevisiae, mediated by secretion of an 11.5 kilodalton (kd) protein toxin, is cytoplasmically determined by the 1.9 kb M1-dsRNA plasmid. Maintenance of M1-dsRNA is dependent on the 4.5 kb L1-dsRNA because L1 encodes the capsid protein of the virus-like particles that separately encapsidate both dsRNA species. We have shown that in vitro translation of denatured M1-dsRNA produces M1-P1, a 32 kd protein containing the toxin peptides. We now demonstrate the presence of an unstable, 42 kd, membrane-associated, glycosylated protoxin in killer cells, probably derived from M1-P1 by cotranslational processing, and glycosylation. In vitro cotranslational processing of M1-P1, derived both from in vivo mRNAs and from denatured M1-dsRNA, produces a product resembling protoxin. Processing involves loss of 1.6 kd of protein, presumably an N-terminal leader peptide, and glycosylation. This information, together with data on in vitro expression of suppressive deletion mutants of M1-dsRNA, allows construction of testable models for the functional sequence of M1-P1 and for its maturation to toxin.

Cell Membrane↗
PubMed1980

Influence of various phenolic compounds on Azotobacter.

All the phenolic compounds, viz., nitrophenol, hydroquinone, coumarin, and benzilic acid, inhibited the growth, polysaccharide production, respiration, and nitrogen fixation of different Azotobacter isolates in vitro. Both in the presence and absence of various phenolic compounds a direct correlation between the polysaccharide production and nitrogen fixation was observed. However, no such direct effect was observed with respect to respiration and nitrogen fixation in the Azotobacter isolates tested.

Azotobacter↗
PubMed1977

Dependence of yeast sporulation on mitochondrial protein synthesis.

Sporulation in diploid Saccharomyces cerevisiae is not dependent on continued protein synthesis in the mitochondria. Using chloramphenicol, it is shown that proteins essential for respiration and sporulation are synthesized in mitochondria early during growth in a presporulation medium.

Chloramphenicol↗
PubMedDate not supplied

Phenotypic and genetic diversity of Bacillus thuringiensis strains isolated in India active against Spodoptera litura.

Bacillus thuringiensis strains isolated from different agroclimatic regions of India were found to harbor cry1 family genes. Of 831 strains 18 that were found to produce 130- and 68-kDa mol wt proteins in sodium dodecyl sulfate polyacry1amide gel electrophoresis were subjected to bioassay against second instar larvae of Spodoptera litura. According to the time response curve, while the highest toxic activity against S. litura was observed in PBT-782 with an LT50 of 25.46 h, strains PBT-372, PBT-574, PBT-801, and PBT-716 in descending order of merit had LT50 values of 36.81, 48.18, 50.35, and 73.53 h. The results of the field experiment testing the efficacy of different B. thuringiensis strains in controlling S. litura larvae infecting peanut plants showed that the chemical insecticide chlorpyriphos was the most effective in controlling S. litura throughout the study period. However, among B. thuringiensis strains, PBT-372 was superior. All the B. thuringiensis strains except PBT-689 were found to contain cry1Ac1-type gene. However, only nine strains contained cry1Aa1 gene. While cry1Ab1 was present only in PBT-372 and PBT-689, cry1Ca1 was present in PBT-574, PBT-688, PBT-689, and PBT-695. cry1Da1 was detected only in PBT-688 and PBT-692. None of the strains contained cry1Ba1 and cry1Ea1 genes. When polymerase chain reaction analysis using cry1Ca1 primer was performed, PBT-695 produced an unexpected 739-bp product, which showed 33% homology with cry1Ca1 gene between nucleotides 1819 and 2107. Our results indicated that among the field-collected B. thuringiensis strains, PBT-372 harbors multiple cry-type genes and could be employed for biological control of insects.

Animals↗
PubMedDate not supplied

Mucormycosis presenting as palatal perforation.

Mucormycosis is an opportunistic fungal infection that is caused by normally saprobic organism of the class Zygomycetes. The main form of mucormycosis are pulmonary and rhinocerebral. Rhinocerebral mycormycosis typically starts in the maxillary antrum, particularly in poorly controlled diabetics. Invasion of surrounding tissue can cause necrotizing ulceration of palate with a blackish slough and exposure of bone. A case of mucormycosis presenting as palatal performation is discussed in this article.

Antifungal Agents↗
PubMedDate not supplied

Cemento ossifying fibroma.

Cemento ossifying fibroma is a benign, non odontogenic tumour of the jaw, a subdivision of fibro-osseous lesions. The age of occurrence is between 20 and 40 years. It has a female to male predilection of 2:1. A rare case of cemento ossifying fibroma involving maxilla and mandible in a 30 years old female is presented with a discussion on its clinical and radiographical features, computed tomograph scan findings, histopathological presentation with a review of literature.

Adult↗