Isoflavones from Xanthocercis zambesiaca

In addition to the previously described 7-hydroxy-8,4′-dimethoxy- and 7,3′-dihydroxy-8,4′-dimethoxy-isoflavone the heartwood of Xanthocercis zambesiaca has been shown to contain 7-hydroxy-8,3′,4′-trimethoxy-,3′,4′-dimethoxy-6,7-methylenedioxy- and 8,3′,4′-trimethoxy-6,7-methylenedioxy-isoflavone. A technique of determining isoflavone hydroxylation patterns by deuterium labelling is described.     

The antioxidant activities of seasonings used in Asian cooking. Powerful antioxidant activity of dark soy sauce revealed using the ABTS assay

Scavenging of the ABTS (2,2′-azinobis[3-ethylbenzothiazoline-6-sulphonate])-derived nitrogen-centred radical cation (ABTS^?+) was used to compare the total antioxidant activities of several seasonings used in Asian cooking. The results were expressed as Trolox equivalent antioxidant capacity (TEAC). The TEAC activities of dark soy sauces were found to be exceptionally high. In evaluating the TEAC of commercial products, attention must be paid to the addition of preservatives by manufacturers to the seasonings tested. Sodium benzoate (a preservative added to several seasonings) did not react significantly with ABTS^?+, but the sulphite content of certain white wines may have led to an over-estimation of their TEAC.     

大豆异黄酮对雌鼠初情期等生殖性状的影响

目的通过研究大豆异黄酮对雌鼠初情期等生殖性状的影响,为母鼠的安全饲喂提供实验依据。方法本实验选用210只21日龄ICR雌鼠随机分成3组,饲喂含不同浓度大豆异黄酮（0 mg/kg、50 mg/kg、400 mg/kg）的饲料。每日检查母鼠阴道开张和阴道栓情况。采集母鼠45和65日龄时血清,利用ELISA方法检测血清中雌激素含量,并统计45、65日龄体重和子宫重。利用免疫组织化学方法检测子宫上皮雌激素受体的表达分布情况。结果雌鼠阴道开张的平均日龄分别为27.2 d、26.1 d和25.8 d,400 mg/kg组显著早于剂量为0mg/kg的对照组（P〈0.05）;雌鼠平均初次配种时间各组间差异不显著（P〉0.05）;饲养到45日龄和65日龄时400 mg/kg组雌鼠体重显著高于对照组（P〈0.05）。喂养8周后两个试验组在子宫间质细胞上雌激素受体的阳性细胞表达率显著高于对照组;在腺上皮中400 mg/kg组显著高于50 mg/kg组和对照组（0 mg/kg）;但是在腔上皮中,各组间受体的阳性细胞表达率差异不显著（P〉0.05）。结论饲喂每公斤含400 mg大豆异黄酮的饲料可以刺激初情期前母鼠阴道的开张,提高雌鼠的体重,降低65日龄时血清雌激素含量,并在饲喂8周后影响子宫间质和腺上皮上雌激素受体的表达分布;而饲喂每公斤含50 mg大豆异黄酮的饲料仅对小鼠45日龄体重及饲喂8周后子宫间质上雌激素受体的表达分布有所影响。     

以玉米淀粉糖渣为原料制备米曲发酵酱油

以玉米淀粉糖渣为原料制备米曲,米曲中的中性蛋白酶活力能够达到4000 U/g(干基),糖化酶比活力可达到120 U/g左右,满足酿造酱油所需要求。用糖渣米曲发酵酱油,氨基态氮和总氮质量浓度分别能够达到7.1 g/L和11.9 g/L,还原糖质量浓度为13.2 g/L,各项理化指标均可达到国家二级酱油标准。     

Regulation of soy isoflavones on weight gain and fat percentage: evaluation in a Chinese Guangxi minipig model

This study was conducted to determine the effects of soy isoflavones on changes in body and tissue weight and on insulin-like factor I (IGF-I) and peroxisome proliferator-activated receptor-γ (PPARγ) gene and protein expression in muscle and adipose tissues in Chinese Guangxi minipig, as a model for studying human nutrition. A total of 72 male Chinese Guangxi minipigs were fed basal diet (control, Con), low dose of soy isoflavones and high dose of soy isoflavones (HSI). The results showed that HSI increased the body weight (BW) gain and fat percentage of minipigs (P < 0.05). In addition, the serum concentrations of IGF-I and interleukin-6 were increased by high levels of soy isoflavones (P < 0.05). Furthermore, a diet containing soy isoflavones enhanced IGF-I mRNA expression levels in longissimus muscle, but decreased these levels in perirenal fat. However, the mRNA and protein expression levels of PPARγ in longissimus muscle and subcutaneous adipose tissue were both increased when compared with the Con. The data indicated that soy isoflavones regulated the BW gain and fat percentage of Chinese Guangxi minipigs, which also showed changes in IGF-I system and PPARγ. However, further research is required to clarify the causative relationship.     

大豆异黄酮微生物转化研究进展

大豆异黄酮是大豆在其生长过程中形成的一类次生代谢产物,具有抗氧化、抗癌、减少骨质流失、降低心脑血管发病率等多种生理功能。目前已知,被摄人机体的大豆异黄酮将被肠道微生物菌群转化为具有更高、更广生物学活性的不同产物。因此,大豆异黄酮对人体的有益调节作用强弱并不简单取决于摄人机体的净含量的多少,更在于被摄人机体的大豆异黄酮将如何被肠道菌群转化。本文从大豆异黄酮的组成与功能、大豆异黄酮体内吸收、代谢及微生物转化、转化产物的活性以及高效合成等方面进行了系统综述,对大豆异黄酮微生物生物转化研究现状和存在问题进行分析总结,并对今后发展趋势进行展望,旨在推动高活性大豆异黄酮微生物转化产物的研究与开发。     

Studies on Organophosphorus Pesticides Synthesis of Some Sulphanilamide Derivatives

Several N¹-aryl-N⁴(O, O-diethylthiophosphoryl) sulphanilamides and N¹-aiyl-N⁴-(N, N-diarylthiophosphoramidic) sulphanilamides have been prepared with a view to study their pesticidal properties. Six such compounds have been tested against two species of fungi.     

Identification of the putative N-acetylglucosaminidase CseA associated with daughter cell separation in Tetragenococcus halophilus

ABSTRACT

The lactic acid bacterium Tetragenococcus halophilus, which is used as a starter to brew soy sauce, comprises both cluster-forming strains and dispersed strains. The cluster-forming strains are industrially useful for obtaining clear soy sauce, because the cell clusters are trapped by filter cloth when the soy sauce mash is pressed. However, the molecular mechanism underlying cell cluster formation is unknown. Whole genome sequence analysis and subsequent target sequence analysis revealed that the cluster-forming strains commonly have functional defects in N-acetylglucosaminidase CseA, a peptidoglycan hydrolase. CseA is a multimodular protein that harbors a GH73 domain and six peptidoglycan-binding LysM domains. Recombinant CseA hydrolyzed peptidoglycan and promoted cell separation. Functional analysis of truncated CseA derivatives revealed that the LysM domains play an important role in efficient peptidoglycan degradation and cell separation. Taken together, the results of this study identify CseA as a factor that greatly affects the cluster formation in T. halophilus.     

A simple method of markerless gene deletion in Staphylococcus aureus

Staphylococcus aureus is a Gram-positive pathogen that causes opportunistic infections and a wide variety of diseases. Methicillin-resistant S. aureus (MRSA) is frequently isolated as multidrug-resistant in nosocomial and community infections. Molecular genetic manipulation is an important tool for understanding the molecular mechanism of S. aureus infection. However the number of available antibiotic markers is limited due to multidrug resistance. In this study, we constructed two Escherichia coli-S. aureus shuttle vectors, pKFT and pKFC, that carry a temperature-sensitive origin of replication in S. aureus, lacZ(a) enabling a simple blue-white screening in E. coli, an ampicillin resistant gene, and either a tetracycline resistance gene or a chloramphenicol resistance gene. We report a simple technique using pKFT to construct a markerless gene deletion mutant in S. aureus by allelic replacement without the use of a counter-selection marker. Subculture twice at 25 °C was critical to promote an allelic exchange rate in S. aureus. This technique is very simple and useful to facilitate genetic research on S. aureus.