片球菌素PediocinPA-1抑菌活性检测

目的检测通过基因工程获得的片球菌素Pediocin PA-1抑菌活性。方法采用琼脂扩散法检测片球菌素Pediocin PA-1对单核细胞增生李斯特杆菌、金黄色葡萄球菌、铜绿假单胞菌、沙门菌和大肠埃希菌O157的抑菌活性。结果片球菌素Pediocin PA-1对单核细胞增生李斯特杆菌、金黄色葡萄球菌、沙门菌、铜绿假单胞菌和大肠埃希菌O157等均有抑制作用。其中对单核细胞增生李斯特杆菌、沙门菌、大肠埃希菌和金黄色葡萄球菌的抑制作用效果明显,对铜绿假单胞菌有微弱的抑制作用。结论通过基因工程获得的片球菌素Pediocin PA-1具有抑菌活性。     

产类细菌素乳酸乳球菌V528的紫外线诱变育种研究

目的获取高产抑制鸡白痢沙门菌生长的类细菌素乳酸乳球菌的突变菌株。方法在紫外线照射致死率为82.7%的剂量下,对处于对数生长后期的乳酸乳球菌V528进行紫外线二次复合诱变处理。分别随机对第一次和第二次复合处理后生长的117株和310株菌进行效价测定分析。结果在实验所用的照射剂量下,抑菌效价提高的正突变菌株占有一定优势,负突变菌株较少,其中突变菌株Lact.174的抑菌效价较V528的效价提高了8.48倍,并具有一定的遗传稳定性。结论运用紫外诱变育种技术可有效地获得高产类细菌素的突变菌株。     

一种使用酶标仪快速测定细菌素效价的方法

目的建立快速测定细菌素效价的方法。方法以Nisin为参照物,利用酶标仪测定指示菌吸光度值。结果确定了在指示菌接种量为10%和细菌素作用时间为8 h 2个测定参数条件下,样品效价检测值的相对标准偏差在5%以下。结论所建方法快速、准确,适合检测菌所产细菌素的研究。     

复合型菌剂对雏鸡体内溶血素的影响

利用由鸡粪肠球菌、鸡非致病性大肠埃希菌、芽胞杆菌、酵母菌和乳酸菌组成的复合型菌剂灌喂雏鸡后,再用绵羊红细胞腹腔注射免疫4d,使雏鸡体内产生溶血素（IgM）。通过测定其血清中溶血素的效价,发现灌服不同菌量的雏鸡所产生的溶血素效价比没有灌服的对照组所产生的溶血素效价高出22％～32％。     

《乳酸细菌分类鉴定及实验方法》

该书是乳酸细菌分类鉴定及实验方法的一本专著。该书以全新的概念划定了乳酸细菌类群的范围,汇集了乳酸细菌分类研究的最新动态和资料,并包括这类细菌现有的对个主要属和２２０多个种的分类鉴定特征及其生境、与人类的关系等性状。现有的２３个主要属为：乳杆菌属、肉食杆菌属、链球菌属、肠球菌属、乳球菌属、漫游球菌属（Ｖａｇｏｃｏｃｃｕｓ）、明串珠菌属、片球菌属、气球菌属、双歧杆菌属、奇异菌属、利斯特氏菌属、环丝菌属（Ｂｒｏｃｈｏｔｈｒｉｘ）、丹毒丝菌属、孪生菌属、糖球菌属（Ｓａｃｈａｒｏｃｏｃｃｕｓ）、四联球菌属…     

乳酸乳酸球菌基因表达调控研究进展

乳酸乳酸球菌基因表达调控研究进展还连栋（中国科学院微生物研究所,北京１０００８０）乳酸球菌属（Ｌａｃｔｏｃｏｃｃｕｓ）包括５个种,其中乳酸乳酸球菌（Ｌａｃｔｏｃｏｃｃｕｓｌａｃｔｉｓ）是最典型的一个种。乳酸乳酸球菌以前被称之为乳酸菌或Ｎ群链球菌（Ｓｔ...     

Pfk基因过表达对乳酸乳球菌N8产nisin速率的影响

【目的】通过基因工程手段增加糖酵解途径中编码限速酶6-磷酸果糖激酶基因Pfk在乳酸链球菌素(nisin)产生菌Lactococcus lactis N8中的表达,增快nisin的产生,从而提高单位时间内nisin的产量,缩短发酵周期。【方法】将pfk基因及编码以c AMP为依赖的蛋白激酶催化亚基基因pka C克隆到表达质粒p MG36e上,将共表达重组质粒转入L.lactis N8中,使Pfk-pka C基因过量表达,得到重组菌株L.lactis N8-p MG36epfk-pka C,并比较该重组菌株与野生菌的生长曲线、胞内6-磷酸果糖激酶活性、发酵上清液的抑菌活性及效价,并从转录水平分析两株菌nis A及pfk-pka C的转录差异,比较野生菌与重组菌在不同葡萄糖含量下培养产nisin的变化。【结果】Pfk基因与pka C基因的过表达对重组菌的生长速度没有明显的影响,却能提高重组菌产nisin的速度,在发酵10 h时nisin的产量比野生菌提高了20%,使得发酵周期缩短近2 h。野生菌及重组菌在不同葡萄糖含量下培养发酵上清液的nisin效价没有明显的变化。【结论】糖酵解途径中6-磷酸果糖激酶基因Pfk的过表达可以加快乳酸乳球菌N8产nisin的速率,缩短发酵周期。     

乳酸L-68型粪肠球菌对肉鸡生产性能和免疫功能的影响

目的研究乳酸L-68粪肠球菌对肉鸡的生产性能和免疫功能的影响。方法选用3000羽1日龄的艾维菌肉用仔鸡,随机分为两个处理组,每组1500羽。对照组饲喂基础日粮,实验组饲喂基础日粮并在饮水中加入微生态制剂乳酸L-68粪肠球菌,实验期为42d。通过检测平均周增重、料肉比、鸡群的健康状况、抗体水平和器官指数探索该制剂对肉鸡的促生长和免疫增强作用。结果微生态制剂实验组鸡的周增重、料肉比、抗NDV的HI效价、免疫器官指数均优于对照组鸡,差异有显著性（P〈0．05）。结论肉鸡饮水中添加乳酸L-68粪肠球菌,能促进免疫器官的生长发育,提高免疫器官指数;能明显提高循环抗体的水平,因而能促进仔鸡的生长发育,降低料肉比。     

猪流行性腹泻抗原基因在乳酸菌中的表达及优化

目的：优化猪流行性腹泻抗原基因COE在乳酸乳球菌中的表达。方法：将表达猪流行性腹泻抗原基因COE的重组乳酸菌活化,酶切鉴定其稳定性,然后设计实验分别从pH值、温度、Nisin浓度、诱导时间、菌体密度等条件对COE表达进行优化,SDS-PAGE检测表达效果。结果：COE在乳酸乳球菌中的最佳表达条件为pH 7.0、T（温度）=30℃、Nisin=2ng/mLt、（诱导时间）=4h和OD600=0.5,在以上条件下相对表达量分别达到了15.48%、15.05%、15.82%、14.72%和20.47%。在最佳表达条件下得到SOE的相对表达含量达到21%。结论：COE重组质粒稳定,其在乳酸菌中经优化表达后可为今后研制猪流行性腹泻乳酸菌疫苗提供数据。     

乳酸乳球菌食品级表达载体的研究进展

乳酸乳球菌（L.lactis）是乳球菌属中最重要和最典型的一个种,在食品工业中应用广泛,被公认为安全的（generally regards as safe,GRAS）食品级微生物。以乳酸乳球菌作为宿主菌,构建表达载体用来表达异源蛋白和酶,逐渐成为食品工业、生物制药和疫苗研究的热点。近年来,乳酸乳球菌的分子微生物学研究取得了重大进展,这为表达载体的构建奠定了基础,一些具有不同用途的乳酸乳球菌基因表达载体已经构建,用来表达抗原蛋白、细胞因子和生物酶等。其中,以来源于食品级微生物的DNA片段构建的食品级表达载体引起人们的关注。     

Effect of Environmental Factors in Aerobiosis and Anaerobiosis on the Growth and Activity of Propionic Acid Bacteria Evaluated by Pressure Measurement

The effects of air, N₂ and CO₂ atmospheres on the growth and metabolism of P. shermanii CIP 10 30 27 under “optimum conditions” (pH 6.5, NaCl 0 %, temperature 30 °C) and “stressful conditions” (pH 5.3, NaCl 2.1 %, temperature 20 °C) simulating cheese ripening conditions were investigated using a pressure measurement technique. Under both conditions, the inhibition of growth was at its maximum when a CO₂ atmosphere with an increase in the lag phase (L_P) from 3 to 80 h and a reduction in the maximum rate of pressure variation (V_max,P) from 2.5 to 0.4 kPa/h was used. The production of metabolites was not affected under “optimum conditions”, but under “stressful conditions”, propionate production increased and higher ratios of propionate to acetate of up to 2.45 were observed. The effects of air and N₂ atmospheres on both growth and metabolite production were also examined.     

化学-酶法制备L-高苯丙氨酸

以苯丙酸乙酯为原料,通过正交设计优化2-氧4-苯基丁酸盐的制备条件：苯丙酸乙酯与草酸二乙酯摩尔比为1：3,缩合反应时间为2．5h,H2SO4质量分数为20％,水解反应时间为15h,优化条件下2-氧-4-苯基丁酸盐的产率为68．24％。随后,利用E．coli A5所产的天冬氨酸转氨酶为生物催化剂制备L-高笨丙氨酸。酶转化反应的最适条件为：游离细胞体系pH、温度、底物质量浓度和细胞质量浓度分别为8．5、37℃、20g/L和30g／L;而固定化细胞体系则分别为7．0—9．0、40℃、10g／L和30g/L。采用廉价的L-谷氨酸（L—Glu）作为氨基供体,添加表面活性剂有利于提高L-HPA产率。通过研究固定化细胞转化反应进程,结果发现8h内90％的底物可转化为L—HPA。     

Construction of two <Emphasis Type="Italic">lux</Emphasis>-tagged Hg<Superscript>2+</Superscript>-specific biosensors and their luminescence performance

Two Hg2+-specific biosensors were constructed using bacterial luciferase as reporter gene and plasmid-free Pseudomonas putida X4 and Enterobacter aerogenes NTG-01 as host strains. The performance of X4 biosensor was compared with that of NTG-01 biosensor in the same assay conditions. The maximum bioluminescence for X4 (pmerRluxCDABE-Kan) biosensor was found during the midexponential phase and that for NTG-01 (pmerRluxCDABE-Kan) was at the late exponential phase. The shortest induction time of two biosensors was 30 min. The maximum light signal output for NTG-01 and X4 sensors was observed at the incubation time of 5 and 4 h, respectively. The lowest detectable concentration of mercury by the two biosensors were both of 100 pM at 28 degrees C, pH 7 and an initial cell number of 10(6) CFU ml(-1). Cd2+, Zn2+, Co2+, Cu2+, and Pb2 + ions at nanomolar level did not interfere with the measurement by the biosensors. These results show that the sensitivity of the two biosensors is sufficient for the detection of Hg2+ under most contaminated environments.     

Effects of feeding schedules on diurnal periodicity of Leucocytozoon smithi gametocytes in the peripheral blood of domestic turkeys

Eighteen domestic turkeys naturally infected with Leucocytozoon smithi Laveran & Lucet were maintained on restricted feeding schedules under conditions of either continuous light or natural light (light 13 h:darkness 11 h) photoperiods. Peripheral gametocyte numbers of L. smithi in all turkeys were determined every 2 h over a 36-h period. Peripheral gametocyte numbers of turkeys maintained under continuous light and restricted to either a 10-h feeding period (9:30 p.m. to 7:30 a.m.) once a day or a 2-h feeding period twice a day (7:30 a.m. to 9:30 p.m. and 7:30 p.m. to 9:30 p.m.) increased at or near the time of feed availability. Under natural photoperiod, gametocyte periodicity was not affected by restricting feed availability to the dark phase of the light-dark cycle. Mean parasite numbers were highest during the light phase when feed was not available, and lowest during the dark period when feed was accessible.     

辅酶Q_(10)产生菌发酵条件的优化

对辅酶Q10生产菌株鞘氨醇单胞菌YZ0803的发酵条件进行优化,确定发酵时间为90 h,250 mL摇瓶装液量为30 mL。培养基组成(质量分数,下同):葡萄糖1.5%,淀粉2.5%,黄豆饼粉2.5%,(NH4)2SO40.5%,NaCl0.03%,K2HPO40.02%,MgSO40.005%。优化后的辅酶Q10产量达到192 mg/L,比采用基础培养基的产量(138mg/L)提高了39.13%。     

pH影响Ca~(2 )和EGTA对水霉(Saprolegnia ferax)菌丝顶端生长的作用效应

水霉(Saprolegia ferax)菌丝在pH6.0-8.0的OM液体培养基中生长良好,在pH5.0时生长速率有所下降,在pH3.0—4.0时停止生长。短时间(30min)作用研究表明,低浓度的CaCl_2促进pH5.0(1—5mmol/L)和pH6.0(1mmol/L)条件下的菌丝顶端生长,抑制pH7.0—8.0条件下的菌丝生长。1mmol/L以上的EGTA则抑制pH5.0条件下菌丝顶端生长,促进pH6.0—8.0条件下的菌丝顶端生长。但CaCl_2和EGTA都不能使pH3.0—4.0条件下的菌丝恢复生长。长时间(8h)作用跟踪观察表明,2mmol/L EGTA(pH6.8)短时间作用可促进菌丝生长,但随着培养时间延长,则产生抑制作用,并诱导原生质从菌丝最顶端喷出。说明细胞壁Ca~(2 )起着提供胞外Ca~(2 )源和细胞壁修饰成分的双重作用。Ca~(2 )通道阻断剂verapamil对菌丝顶端生长的抑制作用也说明顶端生长所需的Ca~(2 )来自胞外。     

Daytime intermittent bright light effects on processing of laterally exposed stimuli, mood, and light perception

Little is known about intermittent bright light (IBL) exposure during the daytime on oscillations in human performance and mood. The aims of this study were to determine whether the applied regime of IBL can differentially influence the daily oscillations of processing of laterally exposed stimuli, as well as the daily course of alertness and affective state, and the participants' perception of light conditions. A counter-balanced, within-subject study design was applied. Performance and mood of 20 student volunteers were measured every 30 min starting at 08:00 h and ending at 20:30 h in IBL and ordinary room light (ORL) conditions. Near to statistical significance, effects of the IBL regime on performance (i.e., main effect on speed of verbal logical task, and interactive effect of light conditions and measurement time on daily oscillations in speed of processing of spatial tasks) and mood (i.e., interactive effect of bright light and measurement time on global vigor assessment) were found. An assessment of IBL conditions as significantly less comfortable and natural and more glaring when compared to ORL conditions draws attention to the importance of participants' perception of the light, which may affect the application of bright light in real life situations.     

Daytime Intermittent Bright Light Effects on Processing of Laterally Exposed Stimuli,Mood, and Light Perception

Little is known about intermittent bright light (IBL) exposure during the daytime on oscillations in human performance and mood. The aims of this study were to determine whether the applied regime of IBL can differentially influence the daily oscillations of processing of laterally exposed stimuli, as well as the daily course of alertness and affective state, and the participants' perception of light conditions. A counter‐balanced, within‐subject study design was applied. Performance and mood of 20 student volunteers were measured every 30 min starting at 08:00 h and ending at 20:30 h in IBL and ordinary room light (ORL) conditions. Near to statistical significance, effects of the IBL regime on performance (i.e., main effect on speed of verbal logical task, and interactive effect of light conditions and measurement time on daily oscillations in speed of processing of spatial tasks) and mood (i.e., interactive effect of bright light and measurement time on global vigor assessment) were found. An assessment of IBL conditions as significantly less comfortable and natural and more glaring when compared to ORL conditions draws attention to the importance of participants' perception of the light, which may affect the application of bright light in real life situations.     

Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions - Effect of Velocity

Background

Inertial measurement of motion with Attitude and Heading Reference Systems (AHRS) is emerging as an alternative to 3D motion capture systems in biomechanics. The objectives of this study are: 1) to describe the absolute and relative accuracy of multiple units of commercially available AHRS under various types of motion; and 2) to evaluate the effect of motion velocity on the accuracy of these measurements.

Methods

The criterion validity of accuracy was established under controlled conditions using an instrumented Gimbal table. AHRS modules were carefully attached to the center plate of the Gimbal table and put through experimental static and dynamic conditions. Static and absolute accuracy was assessed by comparing the AHRS orientation measurement to those obtained using an optical gold standard. Relative accuracy was assessed by measuring the variation in relative orientation between modules during trials.

Findings

Evaluated AHRS systems demonstrated good absolute static accuracy (mean error < 0.5^o) and clinically acceptable absolute accuracy under condition of slow motions (mean error between 0.5^o and 3.1^o). In slow motions, relative accuracy varied from 2^o to 7^o depending on the type of AHRS and the type of rotation. Absolute and relative accuracy were significantly affected (p<0.05) by velocity during sustained motions. The extent of that effect varied across AHRS.

Interpretation

Absolute and relative accuracy of AHRS are affected by environmental magnetic perturbations and conditions of motions. Relative accuracy of AHRS is mostly affected by the ability of all modules to locate the same global reference coordinate system at all time.

Conclusions

Existing AHRS systems can be considered for use in clinical biomechanics under constrained conditions of use. While their individual capacity to track absolute motion is relatively consistent, the use of multiple AHRS modules to compute relative motion between rigid bodies needs to be optimized according to the conditions of operation.     

Safety, pharmacokinetics, and pharmacodynamics of oral apoA-I mimetic peptide D-4F in high-risk cardiovascular patients

Patients with coronary heart disease or equivalent risk received a single dose of 30, 100, 300, or 500 mg of unformulated D-4F (n = 8, each dose) or placebo (n = 8) under fasting conditions. An additional 10 patients received 500 mg (n = 8) or placebo (n = 2) with a low-fat meal. There were no significant trends in any safety parameter. D-4F was detectable in plasma at all doses with a T(max) of 30 min, 1 h, and 2 h for 30, 100, and > or = 300 mg, respectively. The area under the curve((0-t)) was 27.81 ng/hr/ml and 54.71 ng/hr/ml for the 300 mg and 500 mg dose groups, respectively, and 17.96 ng/hr/ml for the 500 mg dose given with food. HDL from each time point for each subject was tested for its ability to inhibit LDL-induced monocyte chemotactic activity in cultures of human aortic endothelial cells. The values obtained were normalized to 1.0 for LDL alone to obtain the HDL inflammatory index. This index significantly improved at 4 h at the 300 mg dose and at 2 h at the 500 mg dose compared with placebo (P < 0.05). There were no changes in plasma lipid or lipoprotein levels. We conclude that unformulated D-4F has low bioavailability that is improved under fasting conditions, and that a single dose of D-4F is safe and well tolerated and may improve the HDL anti-inflammatory index.