A tandem enzymatic hydrolysis of 3-acetylthio-2-methylpropionic methy ester

Summary Enzymatic hydrolysis of racemic 3-acetylthio-2-methylpropionic methyl ester catalyzed by bovine pancreatic protease and Mucor javanicus lipase showed opposite enantioselecivity. A tandem hydrolysis of the ester catalyzed by these two enzymes gives enantiomerically enriched (S)-3-acetylthio-2-methylpropionic acid, a building block of captopril.     

Mutations that affect regulation of the korB gene of Streptomyces lividans plasmid plJ101 alter plasmid transmission

Using the catechol dehydrogenase gene as a reporter, we isolated random mutations in the plJ101 korB gene operator/promoter (OP) region that affect korB expression and regulation. We mapped these mutations to inverted repeat sequences within the promoter and studied their effects on binding of the KorB repressor protein to the OP, on expression of the korB gene, and on plasmid transmission during mating. Additionally, we investigated the biological effects of KorB binding to a locus (sti, for st rong I ncompatibility) adjacent to the korB OP and implicated in plJ101 replication. Our results identify sites that influence the synthesis and autoregulation of KorB; they also show that interaction of KorB with sti affects repression of korB and transmission of plasmids to spores of recipients.     

Identification of SNPs in Closely Related Temperate Japonica Rice Cultivars Using Restriction Enzyme-Phased Sequencing

Very low polymorphism in the germplasm typically used by breeding programs poses a significant bottleneck with regards to molecular breeding and the exploitation of breeding materials for quantitative trait analyses. California rice cultivars, derived from a very small base of temperate japonica germplasm and having a relatively brief breeding history, are a good example. In this study, we employed a reduced representation sequencing approach called Restriction Enzyme Site Comparative Analysis (RESCAN) to simultaneously identify and genotype single nucleotide polymorphisms (SNPs) in forty-five rice cultivars representing the majority of the 100 year-old breeding history in California. Over 20,000 putative SNPs were detected relative to the Nipponbare reference genome which enabled the identification and analysis of inheritance of pedigree haplotypes. Haplotype blocks distinguishing modern California cultivars from each other and from the ancestral short grain temperate japonica cultivars were easily identified. Reduced representation sequencing methods such as RESCAN are a valuable alternative to SNP chip genotyping and low coverage whole genome sequencing.     

Radiosensitizing effects of curcumin alone or combined with GLUT1 siRNA on laryngeal carcinoma cells through AMPK pathway-induced autophagy

In this study, we investigated the ability of curcumin alone or in combination with GLUT1 siRNA to radiosensitize laryngeal carcinoma (LC) through the induction of autophagy. Protein levels in tumour tissues and LC cells were measured by immunohistochemistry and Western blotting. In vitro, cell proliferation, colony formation assays, cell death and autophagy were detected. A nude mouse xenograft model was established through the injection of Tu212 cells. We found that GLUT1 was highly expressed and negatively associated with autophagy-related proteins in LC and that curcumin suppressed radiation-mediated GLUT1 overexpression in Tu212 cells. Treatment with curcumin, GLUT1 siRNA, or the combination of the two promoted autophagy. Inhibition of autophagy using 6-amino-3-methypourine (3-MA) promoted apoptosis after irradiation or treatment of cells with curcumin and GLUT1 siRNA. 3-MA inhibited curcumin and GLUT1 siRNA-mediated non-apoptotic programmed cell death. The combination of curcumin, GLUT1 siRNA and 3-MA provided the strongest sensitization in vivo. We also found that autophagy induction after curcumin or GLUT1 siRNA treatment implicated in the AMP-activated protein kinase-mTOR-serine/threonine-protein kinase-Beclin1 signalling pathway. Irradiation primarily caused apoptosis, and when combined with curcumin and GLUT1 siRNA treatment, the increased radiosensitivity of LC occurred through the concurrent induction of apoptosis and autophagy.     

Isolation and characterization of a new picornavirus in Taiwan]

During the 1971 outbreaks of acute hemorrhagic conjunctivitis, 298 cases were admitted to the Veterans General Hospital and seven strains of new picornavirus were isolated in human epidermoid carcinoma cells. Two strains of the virus isolated have been further studied. Serological neutralization indicated that these isolates might represent a distinct picornavirus group. Biophysical and biological properties determined by this study indicated that the viruses had many characteristics in common with the echoviruses such as morphological appearance, lack of essential lipids, acid stability, density in cesium chloride, sedimentation rate, growth in the presence of 5-iodo-2-deoxyuridine 5-bromo-2-deoxyuridine and nonpathogenicity to suckling mice. However, they were differentiated into 2 strains on the basis of plaque size and neutralization kinetics.     

Biochemical properties of a penicillinase from Escherichia coli carrying Rms 298.

We obtained two R plasmids, i.e., Rms195 and Rms298, from a clinical isolate, E. coli GN5503. Penicillin beta-lactamase (PCase) was extracted from ML1410 Rms195+ and Rms298+, and was purified by chromatography. Rms195 PCase was identical to the type I PCase mediated by R-TEM, RI and Rms212. The isoelectric point of Rms298 PCase was 5.9 and its molecular weight was 21,000 +/- 1,000. The substrate profile and physiochemical properties indicate that Rms298 PCase belongs to the type IV PCase mediated by Rms139 isolated from Pseudomonas aeruginosa.     

Human endothelin converting enzyme-2 (ECE2): characterization of mRNA species and chromosomal localization.

Generation of the functionally pleiotropic members of the endothelin vasoactive peptide family is critically catalyzed by unique type II metalloproteases, termed endothelin converting enzymes (ECE). Isolation of human ECE-2 (EC 3.4.24.71) cDNAs revealed deduced open reading frames of 787 and 765 amino acids with approximately 60% identity with human ECE-1. Characterization of mRNA variants revealed mRNA structural diversity at the 5'-terminus. Two mRNA species exist containing distinct first and second exons. Furthermore, in one of these species, an in-frame deletion of the intracytoplasmic domain removed 29 amino acids. Because of the previously reported human genetic diseases ascribed to germline mutations of member genes of the endothelin family, ECE2 was localized in human chromosomes with fluorescence in situ hybridization and radiation hybrid mapping to 3q28-q29 and SHGC-20171/D3S1571, respectively.     

粉葛的离体培养和无糖生根

1植物名称粉葛(Pueraria thomsonii Benth),又名甘葛藤. 2材料类别幼嫩的茎段、茎尖. 3培养条件丛芽诱导培养基:(1)MS 6-BA 0.2mg·L-1(单位下同) NAA 0.2;(2)MS 6-BA 0.5 NAA 0.2;(3)MS 6-BA 1.0 NAA 0.2.继代增殖培养基:(4)MS 6-BA 0.3 NAA 0.3;(5)MS 6-BA0.6 NAA 0.3.无糖生根培养基:(6)MS大量元素 NAA 0.2.粉葛的生根利用箱式无糖培养专利技术[1]进行,基质为蛭石,在培养基中不添加糖分,以C O2作为碳源,培养箱中C O2浓度为0.1%～0.12%,空气流速为2 L·min-1,光照度为5 000lx.在丛芽诱导和继代阶段,培养基中的糖浓度均为3.0%,琼脂的用量为6.0 g·L-1,pH 5.6～5.8.培养温度24～26℃,光照时间10～12 h·d-1,光照度1 500～2000 lx.     

云南野生早花象牙参的组织培养和快速繁殖

1植物名称早花象牙参(Roscoea cautheoides). 2材料类别幼嫩的叶片. 3培养条件(1)诱导培养基:MS 6-BA 1.5 mg·L-1(单位下同) NAA 0.1 水解酪蛋白800 椰子汁50mL·L-1;(2)分化培养基:MS 6-BA 1.0 NAA 0.1;(3)增殖培养基:MS 6-BA 0.6 NAA 0.1;(4)生根培养基:1/2MS 6-BA 0.6 NAA 0.1 活性炭0.1%.上述培养基均加0.6%琼脂、3%蔗糖,pH 5.8.培养温度(20±1)℃、光照时间10 h·d-1,光照度2 000 lx.