Biomedical subjects

K Mo

Publications and source records attributed to K Mo.

5 recordsLinked to original sources

PubMed1997

Biodegradation of methyl t-butyl ether by pure bacterial cultures.

Three pure bacterial cultures degrading methyl t-butyl ether (MTBE) were isolated from activated sludge and fruit of the Gingko tree. They have been classified as belonging to the genuses Methylobacterium, Rhodococcus, and Arthrobacter. These cultures degraded 60 ppm MTBE in 1-2 weeks of incubation at 23-25 degrees C. The growth of the isolates on MTBE as sole carbon source is very slow compared with growth on nutrient-rich medium. Uniformly-labeled [14C]MTBE was used to determine 14CO2 evolution. Within 7 days of incubation, about 8% of the initial radioactivity was evolved as 14CO2. These strains also grow on t-butanol, butyl formate, isopropanol, acetone and pyruvate as carbon sources. The presence of these compounds in combination with MTBE decreased the degradation of MTBE. The cultures pregrown on pyruvate resulted in a reduction in 14CO2 evolution from [14C]MTBE. The availability of pure cultures will allow the determination of the pathway intermediates and the rate-limiting steps in the degradation of MTBE.

Arthrobacter↗

PubMed1988

Production and Characteristics of Avicel-Digesting and Non-Avicel-Digesting Cellobiohydrolases from Aspergillus ficum.

Two immunologically related cellobiohydrolases, cellobiohydrolase I (CBH I) and cellobiohydrolase II (CBH II), were purified from Aspergillus ficum. The Avicel-adsorbable CBH I (molecular weight, 128,000) digested Avicel, cotton, and cellulose powder to cellobiose, but the Avicel-unadsorbable CBH II (molecular weight, 50,000) could not digest those substrates. Both enzymes hydrolyzed insoluble cellooligosaccharides (DP 25) to cellobiose. High-pressure liquid chromatographic analysis of soluble cellooligosaccharide hydrolysates revealed that both enzymes split off strictly cellobiose units from the nonreducing end of the cellulose chain with an exowise mechanism. CBH I showed glucosyltransferase activity, but CBH II did not. The N-bromosuccinimideoxidized CBH I was completely inactive but retained the ability to adsorb to Avicel. This suggested that CBH I has separate sites for binding to cellulose and for catalyzing cleavage of glycosidic linkages. Cellobiohydrolases were of two types, CBH I and CBH II. The former can adsorb to and digest Avicel, while the latter can do neither.

Journal Article↗

PubMed1987

[Heart injuries].

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Cardiac Tamponade↗

PubMed1986

Production and Characteristics of Avicel-Disintegrating Endoglucanase from a Protease-Negative Humicola grisea var. thermoidea Mutant.

Mutational experiments were performed to decrease the protease productivity of Humicola grisea var. thermoidea YH-78 using UV light and N-methyl-N'-nitro-N-nitrosoguanidine. A protease-negative mutant, no. 140, exhibited higher endoglucanase activity than the parent strain in mold bran culture at 50 degrees C for 4 days. The culture extract rapidly disintegrated filter paper but produced a small amount of reducing sugar. About 30% of total endoglucanase activity in the extract was adsorbed onto Avicel. The electrophoretically homogeneous preparation of Avicel-adsorbable endoglucanase (molecular weight, 128,000) showed intensive filter-paper-disintegrating activity but did not release reducing sugar. The preparation also exhibited a highly synergistic effect with the cellulase preparation from Trichoderma reesei in the hydrolysis of microcrystalline cellulose. This endoglucanase was observed via scanning electron microscopy to disintegrate Avicel fibrils layer by layer from the surface, yielding thin sections with exposed chain ends. A mutant, no. 191, producing higher protease activity and an Avicel-unadsorbable, Avicel-nondisintegrating endoglucanase was isolated. The purified enzyme (molecular weight, 63,000) showed no disintegrating activity on filter paper and Avicel and a less synergistic effect with the T. reesei cellulase in hydrolyzing microcrystalline cellulose than did the former enzyme. Endoglucanase was therefore divided into two types, Avicel disintegrating and Avicel nondisintegrating.

Journal Article↗

PubMedDate not supplied

Peritoneoscopic examination using intravenous administration of indocyanine green in the fatty liver.

Forty patients with fatty liver were studied by peritoneoscopic examination after intravenous administration of indocyanine green (ICG). Although diffuse or centrilobular steatosis was observed in both nonalcoholic and alcoholic fatty liver, periportal steatosis was seen only in alcoholic fatty liver. Vascular markings were more prominent in alcoholic fatty liver, especially in those with fibrosis, compared with nonalcoholic fatty liver. Fat was not stained with ICG. Unstained red patches, observed after ICG administration in both nonalcoholic and alcoholic fatty liver, were thought to be due to congestion in the former and to lobular inflammation as well as congestion in the latter. Acinar markings were indistinct in the fatty liver with fibrosis but became clearer after ICG administration.

Adolescent↗