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Biomedical subjects

K Watson

Publications and source records attributed to K Watson.

At least 109 records · Page 6Linked to original sources
PubMed1986

High-Efficiency Carbohydrate Fermentation to Ethanol at Temperatures above 40 degrees C by Kluyveromyces marxianus var. marxianus Isolated from Sugar Mills.

A number of yeast strains, isolated from sugar cane mills and identified as strains of Kluyveromyces marxianus var. marxianus, were examined for their ability to ferment glucose and cane syrup to ethanol at high temperatures. Several strains were capable of rapid fermentation at temperatures up to 47 degrees C. At 43 degrees C, >6% (wt/vol) ethanol was produced after 12 to 14 h of fermentation, concurrent with retention of high cell viability (>80%). Although the type strain (CBS 712) of K. marxianus var. marxianus produced up to 6% (wt/vol) ethanol at 43 degrees C, cell viability was low, 30 to 50%, and the fermentation time was 24 to 30 h. On the basis of currently available strains, we suggest that it may be possible by genetic engineering to construct yeasts capable of fermenting carbohydrates at temperatures close to 50 degrees C to produce 10 to 15% (wt/vol) ethanol in 12 to 18 h with retention of cell viability.

Journal Article↗
PubMed1984

Mitochondrial and cytoplasmic protein syntheses are not required for heat shock acquisition of ethanol and thermotolerance in yeast.

Heat shock acquisition of ethanol- and thermotolerance in Saccharomyces cerevisiae was not inhibited in cells incubated in the presence of cycloheximide or chloramphenicol. Respiratory-deficient (rho-) mutants also characteristically exhibited the heat shock response. It was concluded that mitochondrial and cytoplasmic protein syntheses are not required for heat shock acquisition of ethanol and thermotolerance in yeast.

Chloramphenicol↗
PubMed1984

Immunotherapy with alginate-conjugated and alum-precipitated grass pollen extracts in patients with allergic rhinoconjunctivitis.

In order to compare the safety and the efficacy of two grass pollen extracts made from the same starting material, i.e. equal proportions of cocksfoot and timothy, a 3-year study was made on patients with hay fever. One product was a dialysed aqueous extract of pollens which was chemically conjugated to activated sodium alginate ( Conjuvac ). The other was a pyridine-extracted alum-precipitated crude extract (Allpyral). Forty patients with classical hay fever were admitted to the study. All gave positive result to prick and nasal/conjunctival testing with extracts of both cocksfoot and timothy grass. Thirty-five patients completed all 3 years of the study. Seventeen/eighteen Allpyral-treated and 17/17 Conjuvac -treated patients were subjectively improved. There was no significant difference in symptom scores between the two groups. Challenge tests showed a tendency to reduced sensitivity to allergen in the Conjuvac -treated but not in the Allpyral-treated group. The median values for specific IgG and IgE showed the same pattern of reaction as seen in earlier studies of pollen hyposensitization. There was, however, a greater increase of grass-specific IgG in the Conjuvac -treated patients. No serious adverse effects were seen in any of the treatment groups, but there were slightly fewer side effects in the Conjuvac group.

Adolescent↗
PubMed1981

Whole blood cholinesterase activity in calves after topical treatment with famphur.

Holstein-Friesian calves (n = 12) were treated with famphur at three dosage levels 20.25 mg/kg, 40.5 mg/kg and 60.75 mg/kg. The only changes observed in the calves were pupillary constriction in two calves receiving the high dosage and marked depression of whole blood acetylcholinestrase activity. The length of time the blood acetylcholinesterase activity was reduced was longer than previously reported in Hereford cattle.

Administration, Topical↗
PubMed1980

Latency competence of thirteen HSV-1 temperature-sensitive mutants.

Thirteen temperature-sensitive (ts) mutants of HSV-1 were analysed for their capacity to establish latent infections in the brains of mice. Eleven of the mutants could be classified as latency-positive or -negative; two could not be assigned to either group. Leakiness of mutants in the brain and differences in particle/infectivity ratios were found not to play a role in the results. Ts+ revertants of selected latency-negative mutants regained the capacity to establish latent infections, indicating that it was the ts lesion in these agents which was involved in latency. Ultrastructural studies of neuroblastoma cells infected with various mutants and maintained at the restrictive temperature showed that no absolute correlations could be made between capacity to establish latent infection and synthesis of various morphologically identifiable virus products. Finally, from a comparison of latency characteristics with previously established polypeptide phenotypes of mutants it was concluded that one immediate early and one or more later virus functions are necessary for establishment and/or maintenance of the latent state.

Animals↗
PubMed1980

Biochemical correlations among the thermophilic enteric yeasts Torulopsis bovina, Torulopsis pintolopesii, Saccharomyces telluris, and Candida slooffii.

Spontaneous and drug-induced respiration-deficient mutants were isolated from the thermophilic enteric yeasts Torulopsis bovina and Saccharomyces telluris. The biochemical properties of these yeasts were compared with those of the two naturally occurring respiration-deficient thermophilic yeasts T. pintolopesii and Candida slooffii. Succinate dehydrogenase was not detected in mitochondrial fractions from C. slooffii, but was present in all other species. Cytochrome c oxidase, succinate oxidase, and reduced nicotinamide adenine dinucleotide oxidase were not detected in C. slooffii, T. pintolopesii, and the respiration-deficient mutants. Low-temperature cytochrome spectra revealed the presence of cytochromes aa3, b, c1, and c in T. bovina and S. telluris; cytochromes b, c1, and c in C. slooffii and T. pintolopesii; and cytochromes c1 and c in the spontaneous respiration-deficient mutants. Palmitoleic and oleic acids were the major fatty acids in all the species. It was noteworthy that T. pintolopesii was rich in lauric and myristic acids. CsCl equilibrium centrifugation experiments showed the presence in all the yeasts of a light-buoyant-density (1.6785 to 1.6837-g/cm3) deoxyribonucleic acid band which was identified as mitochondrial deoxyribonucleic acid by its selective elimination on treatment of cells with ethidium bromide. The latter result indicated that the spontaneous respiration-deficient mutants were similar to cytoplasmic petite mutants of S. cerevisiae. Although classical assimilation and fermentation tests indicated that the spontaneous respiration-deficient mutants were strains of T. pintolopesii, it was concluded, on the basis of marked physiological and biochemical differences, that this was not the case.

Candida↗