Biomedical subjects

Li-Jia An

Publications and source records attributed to Li-Jia An.

26 records · Page 2Linked to original sources

PubMed2004

Influence of phospholipid fatty acid composition of plasma membrane on sensitivity of plasma membrane ATPase of a self-flocculating yeast to in vivo ethanol activation and its relationship to ethanol tolerance.

Although alterations in fatty acid composition of phospholipids in plasma membranes had no effect on activities of plasma membrane ATPases of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae cells grown in the absence of ethanol (basal enzymes), they significantly affected the susceptibilities of the enzymes to in vivo activation induced by ethanol: the maximal values for the activated enzymes in cells pregrown with 0.6 mmol/L palmitic, linoleic or linolenic acid respectively were 3.6, 1.5 and 1.2-fold higher than their respective basal levels (in cells grown without ethanol), whereas the corresponding value for cells pregrown in the absence of fatty acid was 2.3-fold, with the concentrations of ethanol for the above maximal in vivo activation of enzymes being 7%, 6%, 6% and 7% (V/V) respectively. The Km values for ATP, the pH profiles, and the sensitivities to orthovanadate of the basal and the activated plasma membrane ATPases were essentially identical; however, the v(max) values of activated enzymes increased significantly. It was found that the characteristics of phospholipid fatty acid composition of plasma membrane leading to the enhanced ethanol tolerance of this strain, were also efficacious to increase the percentage of activation of plasma membrane ATPase per unit of ethanol. These data support a close correlation between the ethanol tolerance of this strain and the sensitivity of its plasma membrane ATPase to the in vivo ethanol-induced activation.

Adenosine Triphosphatases↗

PubMed2003

Enhancing ethanol tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae by Mg2+ via reduction in plasma membrane permeability.

Mg2+ at 3.5 mM increased the tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae to ethanol. After 9 h of exposure to 20% (v/v) ethanol at 30 degrees C, all cells died whereas over 50% remained viable for the cells grown with Mg2+. The effect of Mg2+ is closely related to its ability to decrease plasma membrane permeability of cells subjected to ethanol stress.

Biomass↗

PubMed2003

Molecular cloning and characterization of betaine aldehyde dehydrogenase gene from Suaeda liaotungensis and its use in improved tolerance to salinity in transgenic tobacco.

cDNA encoding betaine aldehyde dehydrogenase (BADH) from the halophyte Suaeda liaotungensis has been cloned, sequenced and expressed in tobacco (Nictiana tabacum 89). The full-length cDNA is 1506 base pairs (bp) long and encodes a 502 amino-acid polypeptide. The cDNA fragment coding for the mature enzyme was cloned into vector pCAMBIA-1301 for expression in tobacco. Southern blotting analysis showed that that the Badh gene was integrated into the genome of tobacco. Tobacco expressing BADH survived on MS medium containing 200 mM NaCl, whereas the untransformed plants turned yellow after about 20 d and died.

Aldehyde Oxidoreductases↗

PubMed2003

Codonopsis pilosula (Franch) Nannf total alkaloids potentiate neurite outgrowth induced by nerve growth factor in PC12 cells.

AIM: To explore the effect of Codonopsis pilosula (Franch) Nannf total alkaloids (DSA) on differentiation induced by nerve growth factor (NGF) in PC12 cells. METHODS: After culturing PC12 cells with DSA in the presence or absence of NGF, neurite outgrowth in PC12 cells and correlated protein kinases were assayed. RESULTS: DSA alone did not exhibit neuritogenic activity, but caused a significant enhancement of NGF (2 microg/L)-induced neurite outgrowth in PC12 cells, and increased the phosphorylation of mitogen-activated protein kinase (MAPK). Furthermore, this enhancing effect was completely blocked by a specific MAPK kinase inhibitor, PD98059. CONCLUSION: DSA enhanced the NGF-induced neurite outgrowth in PC12 cells by amplifying an up-stream step of the MAPK-dependent signaling pathway.

Alkaloids↗

PubMed2003

[The new advance of coupled transcription and translation: translation within the nuclei in eukaryotes].

It is well known that the processes of transcription and translation are coupled in prokaryotes. However, in eukaryotes, shortly after the transcription of the primary transcript begins, modifications and processing occur. After the mature mRNA moleculars are transported from the nuclei to the cytoplasm, the translations begin. It shows that the processes of transcription and translation are not coupled in eukaryotes. But now Iborra et al localized translation sites with [3H] lysine or lysyl-tRNA tagged with biotin or BODIPY in mammalian cells and found that there exited coupled transcription and translation within the nuclei. They estimated that the nuclear translation accounted for about 10% to 15% of protein synthesis in the cell.

English Abstract↗

PubMed2003

Enhancements in ethanol tolerance of a self-flocculating yeast by calcium ion through decrease in plasmalemma permeability.

Ca2+ at 1.64 mmol/L markedly increased ethanol tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae. After 9 h of exposure to 20% (V/V) ethanol at 30 degrees C , no viability remained for the control whereas 50.0% remained for the cells both grown and incubated with ethanol in Ca2+ -added medium. Furthermore, when subjected to 15% (V/V) ethanol at 30 degrees C, the equilibrium nucleotide concentration and plasma membrane permeability coefficient (P' ) of the cells both grown and incubated with ethanol in Ca2+ -added medium accounted for only 50.0% and 29.3% those of the control respectively, indicating that adding Ca2+ can markedly reduce plasma membrane permeability of yeast cells under ethanol stress as compared with the control. Meanwhile, high viability levels acquired by the addition of Ca2+ exactly corresponded to the striking decreases in extracellular nucleotide concentration and P' achieved with identical approach. Therefore, the enhancing effect of Ca2+ on ethanol tolerance of this strain is closely related to its ability to decrease plasma membrane permeability of yeast cells subjected to ethanol stress.

Calcium↗

PubMed2002

Cloning, expression and purification of gussurobin, a thrombin-like enzyme from the snake venom of Gloydius ussuriensis.

Total RNAs were extracted from the venom gland of the snake Gloydius ussuriensis. The cDNA of gussurobin, a thrombin-like enzyme from Gloydius ussuriensis, was cloned and amplified by RT-PCR. Assay of the nucleotide sequence of the cDNA allowed postulation of the complete amino acid sequence for Gloydius ussuriensis, Chinese Viperdae. Its amino acid sequence exhibits significant homology with that of other snake thrombin-like enzymes. The cDNA of gussurobin was inserted into the vector pPIC 9K and expressed successfully in Pichia pastoris, strain GS115. The recombinant gussurobin was separated and purified from 500 ml culture and showed one band on SDS-PAGE.

Amino Acid Sequence↗

PubMed2002

[Rapid amplification of 3' cDNA end of Suaeda liaotungensis betaine aldehyde dehydrogenase using one-step PCR].

Based on part of a known cDNA sequence of Suaeda liaotungensis betaine aldehyde dehydrogenase, we successfully cloned the 3' cDNA end of S. lianotungensis betaine aldehyde dehydrogenase using one-step PCR with a gene-specific primer and universal primer. Compared with the typical 3' RACE, one-step PCR is rapid, simple and inexpensive. It is very rapid to amplify an unknown cDNA 3' end using this method.

Journal Article↗