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Biomedical subjects

Y L Lin

Publications and source records attributed to Y L Lin.

At least 145 records · Page 8Linked to original sources
PubMed1983

Butanol Production by a Butanol-Tolerant Strain of Clostridium acetobutylicum in Extruded Corn Broth.

By employing serial enrichment, a derivative of Clostridium acetobutylicum ATCC 824 was obtained which grew at concentrations of butanol that prevented growth of the wild-type strain. The parent strain demonstrated a negative growth rate at 15 g of butanol/liter, whereas the SA-1 mutant was still able to grow at a rate which was 66% of the uninhibited control. SA-1 produced consistently higher concentrations of butanol (from 5 to 14%) and lower concentrations of acetone (12.5 to 40%) than the wild-type strain in 4 to 20% extruded corn broth (ECB). Although the highest concentration of butanol was produced by SA-1 and the wild-type strain in 14% ECB, the best solvent ratio with respect to optimizing butanol and decreasing acetone occurred between 4 and 8% ECB for SA-1. SA-1 demonstrated higher conversion efficiency to butanol than the wild-type strain at every concentration of ECB tested. Characterization of the wild-type and SA-1 strain in 6% ECB demonstrated the superiority of the latter in terms of growth rate, time of onset of butanol production, carbohydrate utilization, pH resistance, and final butanol concentration in the fermentation broth.

Journal Article↗
PubMed1982

Sialyltransferase activity in leukemia.

Sialyltransferase activity in blasts from acute lymphoblastic leukemia (ALL) was markedly lower (1.68 +/- 1.23 pmol/mg protein) than those (6.18 +/- 2.22 pmol/mg protein) of lymphocytes from normal volunteers (t less than 0.001). On the contrary, enzyme activity was significantly increased in blasts (1.21 +/- 0.38 pmol/mg protein) from acute non-lymphoblastic leukemia, compared to the level (0.53 +/- 0.32 pmol/mg protein) of mature granulocytes (t less than 0.001). In TdT-negative CML in blast crisis, sialytransferase activity (2.11 +/- 0.88 pmol/mg protein) was significantly higher than those of mature granulocytes (t less than 0.001), whereas no significant difference in the enzyme activity was noted between the blasts from TdT-positive CML in blast crisis and from ALL. In TdT-positive ALL cases, there was an inverse relationship (r = -0.85, t less than 0.01) between sialytransferase activity and terminal deoxynucleotidyl transferase (TdT) activity of the blasts. Therefore, sialytransferase in leukocytes may be a unique enzyme in which changes in activity relate to the differentiation or malignant transformation of leukocytes.

DNA Nucleotidylexotransferase↗
PubMed1982

Sialyltransferase activity as a marker for the differentiation of lymphocytes. Increase in sialyltransferase activity of blasts from acute lymphoblastic leukaemia cases by 12-o-tetradecanoylphorbol-13-acetate (TPA).

The level of sialyltransferase activity in leukaemic blasts from acute lymphoblastic leukaemia (ALL) cases was significantly lower (3.29 +/- 2.09 pmoles/5 X 10(7) cells or 1.77 +/- 1.16 pmoles/mg protein) than those (18.80 +/- 4.91 pmoles/5 X 10(7) cells or 7.72 +/- 1.75 pmoles/mg protein) of mature lymphocytes from normal volunteers (T less than 0.001). An inverse relationship between the level of sialyltransferase activity and the level of terminal transferase (TdT)activity was seen in blasts from eight TdT-positive ALL cases. No significant difference was observed in the level of sialyltransferase activity between ALL and cells of chronic myelogenous leukemia (CML) in blast crisis. Short Term culture of ALL blast cells with 12-0-tetradecanoylphorbol-13-acetate (TPA) at the concentration of 10-(6)M to 10-(9)M caused a marked increase in sialyltransferase activity. In one of these three ALL cases the population of TdT-positive cells and the TdT activity of the blasts decreased significantly after culture with TPA. These results suggest that biochemical differentiation of leukaemic lymphoblasts has been induced by the addition of TPA, although morphological changes were not observed. Sialyltransferase activity may be a useful indicator for the analysis of differentiation of lymphocytes.

Cell Differentiation↗
PubMed1981

Biological properties of an influenza A virus-specific killer T cell clone. Inhibition of virus replication in vivo and induction of delayed-type hypersensitivity reactions.

We tested two biological properties of a continuously growing mouse cytotoxic T cell line, L4, which is specific for influenza A virus and has been cloned and recloned many times. We previously reported that L4 cells are H-2 restricted and cross-reactive for all type A influenza viruses, whereas they do not recognize type B influenza viruses. They bear Thy-1 and Lyt-2 markers. In the present study, we show that L4 cytotoxic T cells protect mice against a lethal influenza infection on transfer to syngeneic recipients, and reduce virus titers in the lungs of mice challenged with a heterologous type A influenza virus. This provides further support for the active role of cytotoxic T cells in limiting virus replication in influenza infection. We could also demonstrate that the cloned cytotoxic T cells induce a delayed-type hypersensitivity skin reaction in the footpads of mice challenged with live or inactivated influenza virus. This reaction can be observed at 24 h, but has declined by 48 h. A clone of cells derived from L4 that has lost its cytotoxic potential and its ability to recognize infected cells did not induce a delayed-type hypersensitivity reaction in the presence of virus. Thus, cytotoxic T cells actively killing influenza virus-infected cells are able to induce a delayed-type hypersensitivity skin reaction to homologous and heterologous type A influenza viruses.

Animals↗