小分子免疫调节剂 L—2—(3—羟基—4—羟甲基苯基)—甘氨酸前体物 DL—2—(3—羟基—4—羟甲基苯基)—N—乙酰基甘氨酸的合成

本文通过对小分子免疲调节剂L—2—(3—羟基—4—羟甲基苯基)—甘氨酸(英文名:Forphenicinol)前体物DL—2—(3—羟基—4—羟甲基苯基)—N—乙酰基甘氨酸的合成方法研究,探索了终产物Forphenicinol 的合成路线及实验方法、并通过对各步产物之红外光谱分析,确证各步产物之主要特征吸收峰,为今后的合成工作打下良好之基础、     

DL—1—(2,6—二甲基苯氧基)—2——氨基丙烷氨基酸衍生物的研究

<正> DL—1—(2,6—二甲基苯氧基)—乙—氨基丙烷盐酸盐,商品名为慢心律(Mcxiletine)是七十年代进行临床研究的一个抗心律失常药物。目前国内外广泛用于临床,其特点是可以长期口服治疗和预防室性心律失常。根据国内外近十年的临床观察,若用量超过600—800mg/日,则有明显副作用如神经兴奋、噁心、复视、抽搐、振颤等。为了寻找更理想的抗心律失常药物,国内外已做过一些慢心律的类似物供药理筛选研究。本文是从前体药物的角度以慢心律自由碱DL—1—(2,6—甲基苯氧基)—2—氨基丙     

新型O—连接糖基化—O—GlcNAc

一种新型糖基化,单糖Ｎ－乙酰葡萄糖胺通过Ｏ－连接与蛋白质共价相连,随着研究的不断深入,这种新型糖基化受到愈来愈多的重视,本主要论述它的发现,存在部位及可能的功能。     

越南——黄连国家公园

说起越南,国人头脑里首先出现的是下龙湾、芽庄、岘港这些海边的旅游胜地,而相比之下西方人则更钟情于越南北部大山里的一个小县——沙坝（Sa Pa）。这个被誉为亚洲的＂欧洲小镇＂＂越南丽江＂的地方不仅有美丽的法式风格建筑和独特的越南少数民族的风情,更著名的名片则是秀色可餐的黄连国家公园。     

水中精灵——热带鱼

一说起热带鱼,很多人脑海中就浮现出色彩斑斓的小鱼欢快游动的情景,但是这情景很可能是朦胧的,因为我们大多数人对于热带鱼都没有很清晰的概念,也可以说,热带鱼本身就没有一个明确的定义。     

非典—SARS—冠状病毒

2002年11月,一种神秘不明的疾病出现在我国广东省继而肆虐全球,世界上有27个国家和地区相继报道出现这种疫情。由于这种疾病的症状不同于典型肺炎,故初期称之为“非典型肺炎”(简称“非典”)并沿用至今。其学名应称为“严重急性呼吸综合征”(Severe Acute Respiratory Syndrome,     

Enhanced phenylpyruvic acid production with Proteus vulgaris in fed-batch and continuous fermentation

Phenylpyruvic acid is a deaminated form of phenylalanine and is used in various areas such as development of cheese and wine flavors, diagnosis of phenylketonuria, and to decrease excessive nitrogen accumulation in the manure of farm animals. However, reported phenylpyruvic acid fermentation studies in the literature have been usually performed at shake-flask scale with low production. In this study, phenylpyruvic acid production was evaluated in bench-top bioreactors by conducting fed-batch and continuous fermentation for the first time. As a result, maximum phenylpyruvic acid concentrations increased from 1350 mg/L (batch fermentation) to 2958 mg/L utilizing fed-batch fermentation. Furthermore, phenylpyruvic acid productivity was increased from 48 mg/L/hr (batch fermentation) to 104 and 259 mg/L/hr by conducting fed-batch and continuous fermentation, respectively. Overall, this study demonstrated that fed-batch and continuous fermentation significantly improved phenylpyruvic acid production in bench-scale bioreactor production.     

ELISA测定中TMB显色体系的优化及其稳定性研究

通过对间接酶联免疫测定中显色体系的各影响因素的研究,确定了酶联免疫测定的最优显色体系为二甲基亚砜(DMSO)配制四甲基联苯胺(TMB)浓度为0.3 mg/mL的溶液为A液,pH5.5,0.2 mol/L磷酸氢二钠与0.1 mol/L柠檬酸缓冲液配制过氧化脲素浓度为0.74 mg/mL的溶液为B液,两者按一定比例混合后使用。试验结果表明,此显色体系在25-40℃内进行都可得到较为准确的结果,且A、B液混合后在室温下放置4 h仍可使用。A液及B液分别在4℃放置60 d后混合使用仍不影响测定结果。     

青花菜与白菜间体细胞杂种获得与遗传特性鉴定

为获得芸薹属白菜Brassica campestris与青花菜Brassica oleracea var. botrytis的种间体细胞杂交体,以青花菜和白菜的子叶与下胚轴为材料,分离制备原生质体,用40％聚乙二醇 (Polyethylene glycol,PEG) 进行原生质体融合。融合细胞在以0.3 mol/L 蔗糖、0.3 mol/L葡萄糖为渗透稳定剂,附加0.2 mg/L 2,4-D+0.5 mg/L 6-苄氨基嘌呤 (6-BA) +0.1 mg/L 1-萘乙酸 (NAA) +0.1 mg/L激动素 (Kinetin,Kin) 的改良K8p培养基中液体浅层培养。将包埋于0.1％琼脂糖的8~10个细胞期的细胞在添加0.3 mol/L蔗糖和2 mg/L 6-BA+2 mg/L玉米素 (Zeatin,ZEA) +1 mg/L NAA+0.5 mg/L Kin的Kao培养基中诱导愈伤组织。愈伤组织转到MS+5 mg/L ZEA+2 mg/L IAA诱导不定芽。将长1～2 cm的不定芽转到1/2 MS+0.2 mg/L NAA诱导生根。将生根的植株转移到花盆,并对其杂种性质进行形态学、细胞学和分子生物学鉴定。结果表明,融合细胞培养2～7 d后发生第1次分裂,培养35 d后植板率为0.66％,不定芽再生率达3.7％。形态学观察显示,绝大多数再生植株的叶面积较大,株型和叶型为两种杂交亲本的中间型。染色体计数结果显示,再生植株染色体数目为2n=38。流式细胞仪测定DNA含量显示,再生植株DNA含量是亲本之和。随机扩增多态性DNA (Random amplified polymorphic DNA,RAPD) 和基因组原位杂交 (Genomic in situ hybridization,GISH) 分析结果证明再生植株具有双亲基因组。体细胞杂种花粉育性比较低,杂交、回交后其育性逐渐获得恢复。     

影响枯草芽胞杆菌和荧光假单胞菌原生质体再生的因素

目的：为了提高再生率,对影响革兰阳性菌枯草芽胞杆菌KR株和革兰阴性菌荧光假单胞菌B13株原生质体再生的因素进行研究。方法：研究了酶解时间,再生方式,再生培养基中稳定剂的种类,Ca^2＋、Mg^2＋、琥珀酸钠、L-色氨酸的浓度及培养基的放置时间对KR和B13株原生质体再生的影响。结果：对KR株酶解20min,采用夹层培养,再生培养基中加入0.6mol/L蔗糖、0.03mol/L Ca^2＋、0.02mol/L Mg^2＋、0.3mol/L琥珀酸钠、0.2mol/L L-色氨酸,培养基在37℃放置72h,原生质体再生率可达42.7%;对B13酶解15min,采用夹层培养,培养基中加入0.6mol/L NaCl、0.02mol/L Ca^2＋、0.01mol/L Mg^2＋、0.3mol/L琥珀酸钠、0.1mol/L L-色氨酸,培养基在37℃放置48h,原生质体再生率可达15.3%。结论：影响革兰阳性菌枯草芽胞杆菌KR株和革兰阴性菌荧光假单胞菌B13株原生质体再生的因素是不同的。     

Performance characteristics of a two-stage dark fermentative system producing hydrogen and methane continuously

The performance of a mesophilic two-stage system generating hydrogen and methane continuously from sucrose (10-30 g/L) was investigated. A hydrogen-generating CSTR followed by an upflow anaerobic filter were both inoculated with anaerobically digested sewage sludge, and ORP, pH, gas output, %H(2), %CH(4) and %CO(2) monitored. pH was controlled with NaOH, KOH or Ca(OH)(2). Using NaOH as alkali with 10 g/L sucrose, yields of 1.62 +/- 0.2 mol H(2)/mol hexose added and 323 mL CH(4)/gCOD added to the hydrogen and methane reactors respectively were achieved. The overall chemical oxygen demand (COD) reduction was 92.6% with 0.90 +/- 0.1 g/L sodium and 316 +/- 40 mg/L residual acetate in the methane reactor. Operation at 20 g/L sucrose and NaOH as alkali led to impaired volatile fatty acid (VFA) degradation in the methane reactor with 2.23 +/- 0.2 g/L sodium, 1,885 mg/L residual acetate, a hydrogen yield of 1.47 +/- 0.1 mol/mol hexose added, a methane yield of 294 mL/gCOD added and an overall COD reduction of 83%. Using Ca(OH)(2) as alkali with 20 g/L sucrose gave a hydrogen yield of 1.29 +/- 0.3 mol/mol hexose added, a methane yield of 337 mL/gCOD added and improved the overall COD reduction to 91% with residual acetate concentrations of 522 +/- 87 mg/L. Operation at 30 g/L sucrose with Ca(OH)(2) gave poorer overall COD reduction (68%), a hydrogen yield of 1.47 +/- 0.2 mol/mol hexose added, a methane yield of 138 mL/gCOD added and residual acetate 7,343 +/- 715 mg/L. It was shown that sodium toxicity and overloading are important issues for successful anaerobic digestion of effluent from biohydrogen reactors in high rate systems.     

氨基酸等化学刺激物对异育银鲫摄食行为的影响

实验采用撞球法中的双球法研究异育银鲫对氨基酸等刺激物的摄食行为的反应,运用实验鱼对实验球和空白球啄咬次数不同判断刺激物是否具有促摄食作用,运用刺激物与10-5mol/L丙氨酸啄咬次数的比值来比较不同刺激物间的反应。实验鱼体重为(46.5±9.3)g,刺激物为10-6-10-2mol/L的天冬氨酸、蛋氨酸、赖氨酸、精氨酸、丙氨酸、组氨酸、甜菜碱和乳酸,以及10-6-10-2g/L的鱿鱼提取物复合物。实验记录从第2分钟到第10分钟的数据。结果发现,异育银鲫对多数刺激物的刺激没有反应。天冬氨酸在10-6-10-4mol/L浓度范围内具有明显的促摄食作用,但10-3-10-2mol/L浓度范围内则具有微弱的摄食抑制作用。10-5mol/L和10-4mol/L的天冬氨酸溶液、10-4mol/L的精氨酸溶液对异育银鲫的促摄食作用最强,分别为10-5mol/L丙氨酸刺激作用的4.86、5.15和4.6倍。精氨酸、甜菜碱和乳酸的反应具有明显的浓度-反应效应,平均相对啄咬率分别在10-4mol/L、10-5mol/L、10-5mol/L浓度下达到最高,其他刺激物引起的反应在各浓度下差异不显著。蛋氨酸和乳酸在10-6-10-2mol/L各浓度下显著性地抑制异育银鲫的摄食行为。10-4mol/L精氨酸、10-5mol/L丙氨酸以及10-6、10-3和10-2mol/L赖氨酸对异育银鲫的撞球反应具明显的刺激作用。除甜菜碱和天冬氨酸外,多数刺激物引起摄食行为反应在2-9min期间非常稳定。甜菜碱和天冬氨酸刺激异育银鲫所产生的摄食行为反应有随记录时间的延长逐渐适应的趋势,特别是在10-6-10-4mol/L。       

Phenylacetic acid production by Bacteroides gingivalis from phenylalanine and phenylalanine-containing peptides

Phenylacetic acid production and growth of Bacteroides gingivalis were directly proportional to the trypticase content of the medium. L-Phenylalanine enhanced phenylacetic acid production; 5 mg L-phenylalanine per millilitre stimulated maximum production of phenylacetic acid. Peptides (2-4 amino acids) containing L-phenylalanine also stimulated phenylacetic acid production as did phenylpyruvic acid. Resting cell suspensions of B. gingivalis also produced phenylacetic acid when incubated aerobically in the presence of L-phenylalanine and phenylpyruvic acid. Hydrocinnamic acid (3-phenylpropionic acid) and phenyllactic acid were also produced by resting cell suspensions. Our results suggest that L-phenylalanine and phenylpyruvic acid are both precursors to phenylacetic acid.     

Conversion of Phenylalanine to Benzaldehyde Initiated by an Aminotransferase in Lactobacillus plantarum

The production of benzaldehyde from phenylalanine has been studied in various microorganisms, and several metabolic pathways have been proposed in the literature for the formation of this aromatic flavor compound. In this study, we describe benzaldehyde formation from phenylalanine by using a cell extract of Lactobacillus plantarum. Phenylalanine was initially converted to phenylpyruvic acid by an aminotransferase in the cell extract, and the keto acid was further transformed to benzaldehyde. However, control experiments with boiled cell extract revealed that the subsequent conversion of phenylpyruvic acid was a chemical oxidation step. It was observed that several cations could replace the extract in the conversion of phenylpyruvic acid to benzaldehyde. Addition of Cu(II) ions to phenylpyruvic acid resulted not only in the formation of benzaldehyde, but also in the generation of phenylacetic acid, mandelic acid, and phenylglyoxylic acid. These compounds have been considered intermediates in the biological conversion of phenylalanine. The chemical conversion step of phenylpyruvic acid was dependent on temperature, pH, the availability of cations, and the presence of oxygen.     

饲料中植物油替代鱼油对大西洋鲑肝细胞油酸跨膜吸收的影响

以 1-14C油酸（oleic acid;18:1n-9,OA）为指示剂,研究了不同饲料油源饲喂下大西洋鲑肝细胞膜脂肪酸组成受到改变时该细胞对OA吸收的状况,以探讨植物油（Vegetable oil,VO）替代鱼油（Fish oil,FO）对大西洋鲑肝细胞脂肪酸跨膜吸收的影响,为大西洋鲑饲料中植物油替代鱼油的可行性提供理论依据。试验先以鱼油和大豆油为油源配制两种全价配合饲料,分别饲喂大西洋鲑幼鲑5个月,使其产生不同的脂肪酸组成。在饲养结束后,分离并培养试验鱼肝细胞,将细胞与1-14COA及37.5 mol/L OA（1/30,mol/mol,0.3 Ci/瓶）共孵育2h,收集并测定细胞内OA放射活性,再计算细胞内OA吸收量 nmol/（hmillion cells）。同时,试验采取RT-PCR方法测定了细胞脂肪酸运送蛋白（Fatty acid transport protein,FATP）、脂肪酸移位蛋白（Fatty acid translocase,FAT/CD36）的基因表达量。结果表明,FO和VO组肝细胞对OA吸收分别为（0.9240.258）及（0.8880.179）nmol/（hmillion cells）,两组间无显著差异（P0.05）。RT-PCR的检测结果表明,FAT/CD36和FATP基因表达量在FO与VO两组间均无显著差异（P0.05）。结果表明,从植物油替代鱼油不影响大西洋鲑肝细胞对长链脂肪酸的跨膜吸收方面来看,大西洋鲑饲料中以植物油替代鱼油具有可行性。       

Optimization of culture medium for the production of phenyllactic acid by Lactobacillus sp. SK007

Optimization of medium components for the production of PLA by the strain Lactobacillus sp. SK007, which was isolated from Chinese traditional pickles, was carried out using response surface methodology (RSM) based on a uniform design and a central composite rotatable design (CCRD). The final concentration of the optimized medium was 30 g L(-1) glucose, 5 g L(-1) phenylpyruvic acid (PPA), 47 g L(-1) corn steep liquor, 3 g L(-1) K(2)HPO(4), 3 g L(-1) CH(3)COONa, 30 g L(-1) yeast powder and 3 mL L(-1) Tween-80. A maximum PLA yield of 2.30 g L(-1) was achieved, which was significantly higher than previously reported.