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Biomedical subjects

A Sanyal

Publications and source records attributed to A Sanyal.

63 records · Page 4Linked to original sources

Import of transcription factor MTF1 into the yeast mitochondria takes place through an unusual pathway.

We report studies of the import into mitochondria of MTF1, a nucleus-encoded factor that markedly stimulates the specific transcription of mitochondrial DNA. Unlike most of the mitochondrial precursor proteins studied so far, import of MTF1 does not appear to require a receptor on the outer membrane, membrane potential across the inner membrane, or ATP hydrolysis. Its import is not affected by low temperature. It lacks a cleavable presequence but translocates across the inner membrane through its amino terminus; its sorting is independent of hsp60. Our results indicate an unusual and distinct import pathway for MTF1 into the yeast mitochondria.

Biological Transport↗

Heat shock protein HSP60 can alleviate the phenotype of mitochondrial RNA-deficient temperature-sensitive mna2 pet mutants.

mna2, which belongs to the class I temperature-sensitive pet mutants that lose mitochondrial (mt)RNA at restrictive temperature, was shown by complementation and sequence determination to correspond to the gene coding for HSP60. Both mna2-1 and mna2-2, the two available alleles of mna2, have conservative single amino acid substitutions in the HSP60 gene. Valine substitutes for an alanine (position 47) in mna2-1, and an isoleucine substitutes for a valine (position 77) in mna2-2. These substitutions result in defects in respiration and in steady-state mtRNA accumulation. Wild-type hsp60 alleviates the mtRNA phenotype completely, while partially relieving the respiratory deficiency.

Alanine↗

Induction of carboxymethylcellulase in Macrophomina phaseolina.

Macrophomina phaseolina, the well-known jute pathogenic fungus produces very low levels of both extra- and intracellular carboxymethylcellulase even in the absence of any cellulose as carbon source in the medium. However, the production of these enzymes is greatly induced by soluble carboxymethylcellulose. The carboxymethylcellulase in M. phaseolina is repressed by glucose.

Carboxymethylcellulose Sodium↗

Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy: prospective comparison.

BACKGROUND: The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests. METHODS: Patients with faecal occult blood, haematochezia, iron-deficiency anaemia, or a family history of colon cancer underwent three separate colon-imaging studies--ACBE, followed 7-14 days later by CTC and colonoscopy on the same day. The primary outcome was detection of colonic polyps and cancers. Outcomes were assessed by building an aggregate view of the colon, taking into account results of all three tests. FINDINGS: 614 patients completed all three imaging tests. When analysed on a per-patient basis, for lesions 10 mm or larger in size (n=63), the sensitivity of ACBE was 48% (95% CI 35-61), CTC 59% (46-71, p=0.1083 for CTC vs ACBE), and colonoscopy 98% (91-100, p<0.0001 for colonoscopy vs CTC). For lesions 6-9 mm in size (n=116), sensitivity was 35% for ACBE (27-45), 51% for CTC (41-60, p=0.0080 for CTC vs ACBE), and 99% for colonoscopy (95-100, p<0.0001 for colonoscopy vs CTC). For lesions of 10 mm or larger in size, the specificity was greater for colonoscopy (0.996) than for either ACBE (0.90) or CTC (0.96) and declined for ACBE and CTC when smaller lesions were considered. INTERPRETATION: Colonoscopy was more sensitive than other tests, as currently undertaken, for detection of colonic polyps and cancers. These data have important implications for diagnostic use of colon imaging tests.

Barium Sulfate↗