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Biomedical subjects

B L Liu

Publications and source records attributed to B L Liu.

53 records · Page 3Linked to original sources
PubMed1986

The effect of ring substituents on the mechanism of interaction of exogenous quinones with the mitochondrial respiratory chain.

In uncoupled pig-heart mitochondria the rate of the reduction of duroquinone by succinate in the presence of cyanide is inhibited by about 50% by antimycin. This inhibition approaches completion when myxothiazol is also added or British anti-Lewisite-treated (BAL-treated) mitochondria are used. If mitochondria are replaced by isolated succinate:cytochrome c oxidoreductase, the inhibition by antimycin alone is complete. The reduction of a plastoquinone homologue with an isoprenoid side chain (plastoquinone-2) is strongly inhibited by antimycin with either mitochondria or succinate:cytochrome c reductase. The reduction by succinate of plastoquinone analogues with an n-alkyl side chain in the presence of mitochondria is inhibited neither by antimycin nor by myxothiazol, but is sensitive to the combined use of these two inhibitors. On the other hand, the reduction of the ubiquinone homologues Q2, Q4, Q6 and Q10 and an analogue, 2,3-dimethoxyl-5-n-decyl-6-methyl-1,4-benzoquinone, is not sensitive to any inhibitor of QH2:cytochrome c reductase tested or their combined use, either in normal or BAL-treated mitochondria or in isolated succinate:cytochrome c reductase. It is concluded that quinones with a ubiquinone ring can be reduced directly by succinate:Q reductase, whereas those with a plastoquinone ring can not. Reduction of the latter compounds requires participation of either center i or center o (Mitchell, P. (1975) FEBS Lett. 56, 1-6) or both, of QH2:cytochrome c oxidoreductase. It is proposed that a saturated side chain promotes, while an isoprenoid side chain prevents reduction of these compounds at center o.

Animals↗
PubMedDate not supplied

Production of cyclodepsipeptides destruxin A and B from Metarhizium anisopliae.

Maltose and peptone were the best carbon and nitrogen sources for the production of destruxins from Metarhizium anisopliae. With the addition of 0.1% (w/v) beta-alanine to the basal medium, the yields of cyclodepsipeptides DA and DB were 7.2 and 279 mg/L, respectively, which was 2-fold higher than that of control experiment. Response surface methodology (RSM) was applied to optimize the compositions of maltose, peptone, beta-alanine, and glucose used in a shaker-flask cultivation of M. anisopliae for the production of DA and DB. Estimated optimal compositions for the DA production were maltose 2.58%, peptone 0.72%, beta-alanine 0.02%, and glucose 0.55%. The predicted DA yield was 18.5 mg/L. On the other hand, the optimal compositions for DB production were maltose 2.51%, peptone 0.75%, beta-alanine 0.02%, and glucose 0.43%. A maximum DB yield of 232 mg/L was predicted. These were confirmed by cultivation experiments conducted at the optimized conditions for maximum destruxins production in a shaker-flask. Furthermore, a modest high level of DA (49 mg/L) and DB (268 mg/L) yields were obtained by employing the response surface methodology optimized DB production medium in a no-baffle, stirred-tank fermentor.

Amino Acids↗
PubMedDate not supplied

Clear cell carcinoma of salivary glands: immunohistochemical evaluation of clear tumor cells.

A total of 14 cases of clear cell carcinoma of salivary glands were evaluated by immunohistochemical methods using monoclonal antibodies to cytokeratin (K1.1 and K8.12), vimentin, S-100 alpha and beta subunits, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), MAM-3 and MAM-6 antigens and proliferating cell nuclear antigen (PCNA), as well as polyclonal antibodies to lysozyme (Ly), lactoferrin (la) and Alpha-1-antichymotrypsin (alpha 1-Ach). Histopathologically, the carcinoma was characterized by round or polygonal tumor cells with cytoplasm that does not stain with hematoxylin and eosin, nuclei with little pleomorphism and few or no mitotic figures, and growing in solid sheets, small nests or cords with collagenous stroma. Cytokeratin KL1 and K8.12 was present in few tumor cells with almost negligible to strong reaction in all cases, vimentin in 6, GFAP in 5 cases with multiple-expression of cytokeratin K8.12, vimentin and GFAP in 5 cases. S-100 protein immunoreactivity was the most prominent feature with more intense reaction of S-100 beta than S-100 alpha subunit. NSE reactivity was seen in 6 cases. Ly, La, a1-ch, MAM-3 and MAM-6 antigens were localized in clear cells with various reaction intensities. The authors conclude that the clear tumor cells in clear cell carcinoma of salivary glands are not myoepithelial in origin but epithelial or neuroectodermal/neural crest in origin, showing ductal differentiation at the immunohistochemical level.

Adenocarcinoma, Clear Cell↗