Synthesis of the pyrrole porphobilinogen by sepharose-linked -aminolevulinic acid dehydratase

delta-Aminolevulinic acid dehydratase from Rhodopseudomonas spheroides was covalently linked to Sepharose 4B, which had been activated with cyanogen bromide. A column containing this enzyme gel readily catalyzed the synthesis of the pyrrole porphobilinogen on continuous passage of a solution of delta-aminolevulinic acid. Under the conditions of the procedures, product inhibition was minimized and a 50 to 94 percent yield was attained. A column containing about 1 milligram of enzyme was continuously operated for 27 days. Although its total activity appeared to be reduced about 30 percent at the end of this time, the bound enzyme produced approximately 200 milligrams of porphobilinogen each day, and about 5 grams of the pyrrole were isolated.     

茶味鱼鳔胶原蛋白果冻的研制

以鱼鳔为原料,提取其中的胶原蛋白,琼脂为凝胶剂,乌龙茶为去腥剂和调味剂,研制一种新型茶味鱼鳔胶原蛋白保健果冻.对鱼鳔胶原蛋白与茶汁的比例、琼脂和乌龙茶质量浓度、柠檬酸添加量及白砂糖添加量等工艺条件进行了研究,并采用单因素和正交试验对茶味鱼鳔胶原蛋白果冻的配方进行了优化,得到最佳配方：2 g/100 mL茶汁,1 g/100 mL的琼脂,鱼鳔胶原蛋白和茶汁的比例为1：3.5,每100 mL原液中添加50 mL 1 g/100 mL琼脂,0.07 g柠檬酸,8 g白砂糖.     

营养型番茄果冻的加工工艺研究

[目的]探讨番茄果冻的最佳工艺参数。[方法]以番茄汁、白砂糖为主要原料,以琼脂、明胶、料液比、白砂糖为因素进行单因素和正交试验,研究了各因素对番茄果冻产品感官品质的影响,确定了番茄果冻的最佳工艺参数。[结果]正交试验极差分析表明,琼脂对果冻有较大的影响,其次是明胶和料液比,白砂糖对番茄果冻品质影响不大,这与单因子试验结果一致。从正交试验的分析结果得出番茄果冻的优化工艺参数为:0.25%琼脂、2%明胶、料液比1∶0.5、糖8%。在此工艺条件下制作出的果冻成冻完整,质地均匀,细腻爽滑,酸甜可口,具有番茄风味。[结论]营养型番茄果冻品质优良。该研究为番茄深加工的应用与研究提供了参考依据。     

琼脂柱预筛选法在头孢菌素菌种选育中的应用

[目的]获得高产稳定的头孢菌素优良菌株。[方法]先经UV诱变处理深冷孢子液,再培养单菌落,经富集培养划菌落带,采用琼脂柱预筛选法,通过摇瓶初筛、复筛及斜面传代单菌落菌型考察,研究琼脂柱预筛选法在头孢菌素菌种选育中的应用价值及稳定性。[结果]与单菌落分离直接摇瓶筛选法相比,采用琼脂柱预筛选法筛选单菌落省时、省力,效果好。经琼脂柱预筛选法获得的菌株性能稳定,摇瓶效价平均值高,F1、F2、F3、F4代的摇瓶效价分别高出对照16.7%、33.3%、16.0%、12.0%,其中F2代斜面可确认为生产用斜面。[结论]应用琼脂柱预筛选法进行菌种选育,可提高筛选效率和数量,增加高产菌株的获得几率,缩短筛选时间。     

试纸条法与琼脂扩散法检测IBDV抗体的比较(英文)

[目的]比较分析IBDV抗体的试纸条与琼脂糖扩散两种检测方法。[方法]用自行研制的试纸条法检测鸡血清中的鸡传染性法氏囊病毒抗体,并与传统的琼脂扩散法检测结果进行比较。[结果]试纸条较琼脂凝胶扩散试验敏感8倍,在216份临床样品测定试验中,检出率更高,同时其又具有特异性强、易保存、操作简单快速等优点,故试纸条更适合于临床抗体监测。[结论]该研究结果表明试纸条可替代现有的血清学方法,在抗体监测方面具有极大的推广应用价值。     

Cytopathic effect of canine distemper virus in tissue culture

A characteristic cytopathic effect was obtained with canine distemper virus (Onderstepoort strain) propagated in chick embryo fibroblast monolayer tissue culture. In limiting dilutions the lesions were focal. The titer at the 20th tissue culture passage was approximately 10(5) TCD(50)/ml. Cytopathogenicity was specifically inhibited by distemper immune serum. Minute plaques were produced under agar overlay.     

Human rotavirus type 2: cultivation in vitro

A strain of type 2 human rotavirus (Wa) was grown to relatively high titer through 14 passages in primary cultures of African green monkey kidney (AGMK) cells. This passage series was initiated with virus that had been passaged 11 times serially in newborn gnotobiotic piglets. In contrast, virus present in the stool of patient Wa as well as virus from the first, second, or third passage in piglets could not be propagated successfully in African green monkey kidney cells. Prior to each passage in cell culture, the virus was treated with trypsin and the inoculated cultures were centrifuged at low speed. Cultivation of a type 2 human rotavirus should aid attempts to characterize this virus and to develop a means of immunoprophylaxis for a serious diarrheal disease of human infants.     

Magnesium isotopic composition of interplanetary dust particles

The magnesium isotopic composition of some extraterrestrial dust particles has been measured. The particles are believed to be samples of interplanetary dust, a significant fraction of which originated from the disaggregation of comets and may contain preserved isotopic anomalies. Improvements in mass spectrometric and sample preparation techniques have made it possible to measure the magnesium isotopic composition of the dust particles, which are typically 10 micrometers in size and contain on the order of 10(-10) gram of magnesium. Of the 13 samples analyzed, nine have the terrestrial magnesium isotopic composition within 2 parts per thousand, and one shows isotopic mass fractionation of 1.1 percent per mass unit. A subset of the particles, described as chondritic aggregates, are very close to normal isotopic composition, but their normalized isotopic ratios appear to show nonlinear effects of 3 to 4 parts per thousand, which is near the present limit of detection for samples of this size. The isotopic composition of calcium was also determined in one particle and found to be normal within 2 percent. It is clear that the isotopic composition of interplanetary dust particles can be determined with good precision. Collection of dust particles during the earth's passage through a comet tail or an intense meteor stream may permit laboratory analysis of material from a known comet.     

11种微藻提取物对3种植物病原菌抗菌活性的研究

采用纸片法对11种微藻的不同溶剂提取物、娇柔塔胞藻的粗脂和经过硅胶柱层析后的粗脂的各分离组分进行了抗3种植物病原菌的试验。结果表明,甘薯薯瘟病原细菌对微藻提取物最为敏感,娇柔塔胞藻的乙醚提取物对稻瘟病菌的抗菌活性最强,娇柔塔胞藻的粗脂对3种植物病原菌都有一定的抗菌活性,在娇柔塔胞藻粗脂的各分离组分中,苯洗脱组分对稻瘟病菌的抗菌活性最强。     

鸡减蛋综合症病毒（EDS—76）的分离与鉴定

采取新疆五家渠某鸡场发病鸡病料，接种鸭胚，分离病毒，病料在鸭胚中盲传至第５代，鸭胚尿囊液ＨＡ效价达２１７，ＨＡ可被ＥＤＳ－７６标准阳性血清抑制。免疫电镜观察到了病毒颗粒，表明该病是由ＥＤＳ－７６病毒所致     

Efficient purification of cell culture-derived classical swine fever virus by ultrafiltration and size-exclusion chromatography

Large-scale production of cell culture-based classical swine fever virus (CSFV) vaccine is hampered by the adverse reactions caused by contaminants from host cell and culture medium. Hence, we have developed an efficient method for purifying CSFV from cell-culture medium. Pure viral particles were obtained with two steps of tangential-flow filtration (TFF) and size-exclusion chromatography (SEC), and were compared with particles from ultracentrifugation by transmission electron microscopy (TEM), infectivity and recovery test, and real time fluorescent quantitative PCR (FQ-PCR). TFF concentrated the virus particles effectively with a retention rate of 98.5%, and 86.2% of viral particles were obtained from the ultrafiltration retentate through a Sepharose 4 F F column on a biological liquid chromatography system. CSFV purified by TFF-SEC or ultracentrifugation were both biologically active from 1.0×10^−4.25 TCID₅₀·mL⁻¹ to 3.0×10^−6.25 TCID₅₀·mL⁻¹, but the combination of TFF and SEC produced more pure virus particles than by ultracentrifugation alone. In addition, pure CSFV particles with the expected diameter of 40–60 nm were roughly spherical without any visible contamination. Mice immunized with CSFV purified by TFF-SEC produced higher antibody levels compared with immunization with ultracentrifugation-purified CSFV (P<0.05). The purification procedures in this study are reliable technically and feasible for purification of large volumes of viruses.     

赤泥颗粒和赤泥对污染土壤镉形态分布及水稻吸收的效应

赤泥能促进土壤中镉形态转化(离子交换态向残渣态转化),但赤泥碱性很强,对土壤的功能有一定的破坏,为此采用盆栽试验研究了赤泥粉和改性赤泥颗粒对酸性潮泥田土壤镉形态分布及水稻生长的影响.结果表明,同比例(5％ W/W)赤泥颗粒的pH值较赤泥粉下降2.4个单位,但随着时间的推移,改性后赤泥颗粒中OH-有缓释的趋势;同比例(5％ W/W)赤泥颗粒对镉污染土壤的形态分布影响在修复前期比赤泥粉小,在修复后期与赤泥粉基本相同甚至稍大,但两者对水稻生长影响不同:添加赤泥颗粒导致水稻增产18.3％,添加赤泥粉导致水稻减产33.3％;赤泥粉和赤泥颗粒均能抑制水稻对土壤中镉的吸收,添加量越高,抑制效果越明显;添加合适的赤泥颗粒能促进水稻的生长,反之抑制水稻的生长,通过试验,初步确定水稻生长状况最好的赤泥颗粒添加量为3％( W/W),此时离子交换态最大降幅为32.1％,残渣态最大增幅为13.7％,水稻增产37.35％,糙米镉含量减少43.8％,低于国家食品卫生标准限值(Cd≤0.2 mg·kg-1).     

禽流感病毒H5N1亚型血凝素基因在昆虫细胞中的表达

[目的]研究禽流感病毒H5N1亚型血凝素基因在昆虫细胞中的表达。[方法]将禽流感病毒H5N1亚型HA基因以BamHI和NotI双酶切插入pFastBacI载体构建pFast-H5HA转移载体质粒,然后将pFast-H5HA转入含有穿梭质粒的感受态DH10Bac中发生转座作用,在含有X-gal、IPTG、庆大霉素、卡那霉素和四环素的琼脂平板上筛选白色菌落,通过连续传代4次后获得稳定的重组质粒reBac-mid-H5HA。[结果]将重组质粒reBacmid-H5HA转染Sf9昆虫细胞,获得含有禽流感病毒H5N1亚型HA基因的重组杆状病毒,经间接免疫荧光和Western-blot证实HA基因在昆虫细胞中获得表达。重组杆状病毒表达产物能够凝集鸡红细胞,并能被抗H5N1 HA单抗所抑制。[结论]重组血凝素蛋白在杆状病毒中能获得正确表达,为研制AIVH5亚型检测抗原和亚单位疫苗奠定基础。     

雏鹅新型病毒性肠炎的初步分离和鉴定

从南京某地具典型雏鹅新型病毒性肠炎病变的死亡雏鹅体内分离到一株病毒。用12日龄鹅胚增殖病毒,通过电镜观察到腺病毒样粒子,直径70-120 nm;经与小鹅瘟阳性血清进行中和作用后,接种鹅胚后仍出现死亡。人工感染4日龄健康易感雏鹅,引起发病和死亡,并具有典型雏鹅新型病毒性肠炎的临床症状和剖检特征。用此株病毒感染的鹅胚尿囊液制备的沉淀抗原,经琼脂扩散试验,不能与小鹅瘟病毒阳性血清发生特异性沉淀反应。     

自然感绵羊慢性病毒对新疆卡拉库尔羊品种敏感性研究

【目的】用绵羊进行性肺炎病毒((OPPV)实验感染新疆卡拉库尔羊,为证实新疆卡拉库尔羊对OvLV美国株(OPPV)的敏感性很低,且呈现亚临床性感染。【方法】琼扩试验(AGID)检查血清OvLV抗体和进行病理组织学检查,以确定是否有特征性病变的靶器官。【结果】只有33%的受试羊在首次检查时出现内线和外线,乳腺是最敏感的靶器官,其次是肺。【结论】通过对自然感染绵羊慢性病毒新疆株的新疆卡拉库尔羊的研究,证实了新疆卡拉库尔羊是对OvLV的低敏感性品种。     

University-industry programs

In the report by R. G. Wyatt et al. "Human rotavirus type 2: Cultivation in vitro" (11 Jan., p. 189), in the sentence describing the porcine rotavirus plaque reduction test (p. 190, column 3, line 16), the concentration of pancreatin in the agar overlay should have been given as "0.15 percent of 2.5 percen pantreatin 4 x N. F.; Gibco."     

鸡传染性支气管炎弱毒苗的毒力返强检测

将鸡传染性支气管炎疫苗毒接种10日龄鸡胚,并传至12代,观察鸡胚病变,于72 h收集尿囊液进行负染电镜观察和血凝试验.透射电镜观察到典型的冠状病毒颗粒,致鸡胚的典型病变作用和血凝活性随培养代次的增加显著增强.结果表明,该弱毒苗病毒毒力返强,存在安全隐患.     

抗农作物病原真菌的Streptomyces sp.IIR21菌株分离及其克拉维烷基因簇分析

从神农架烟草种植地土壤中分离出1株对7株农作物病原真菌具有抗性活性菌株,命名为ⅡR21菌株。采用琼脂块法测定,该菌株对稻瘟病菌、立枯丝核病菌、腐霉病菌、禾谷镰刀病菌和黄色镰刀病菌具有较强的抑菌活性。对该菌株的生理生化特性和16SrRNA基因序列同源性比对,初步鉴定ⅡR21菌株属于链霉菌属。经过有机溶剂萃取、硅胶柱层析、薄层层析和制备型高效液相色谱对ⅡR21菌株发酵液进行分离纯化,获得了1个纯度为90.34%的具有抗稻瘟病菌168菌株活性的化合物单体。采用高通量测序技术对ⅡR21菌株进行全基因组测序,通过全基因组序列分析,ⅡR21菌株基因组中包含克拉维烷的合成基因簇,并推测出克拉维烷的合成代谢途径。     

Corn stunt spiroplasma: isolation, cultivation, and proof of pathogenicity

A spiroplasma isolated from corn infected with corn stunt disease has been successfully cultivated in vitro. Acid formation was associated with its growth in liquid medium, and fried egg-shaped or granulated colonies developed on solid agar medium. Healthy leafhopper vectors injected with or allowed to feed on isolates from various serial passages through liquid medium were able to transmit the corn stunt agent to healthy corn plants, inducing typical corn stunt disease in the plants. The spiroplasma was reisolated and cultivated from such diseased plants and was indistinguishable morphologically from the original isolates. These results provide the first definite proof that the corn stunt disease is caused by the corn stunt spiroplasma.     

犬瘟热病毒贵州株CDV-GZ1的分离与鉴定

为丰富我国犬瘟热病(CD)的流行病学资料,同时为CDV贵州分离株主要抗原基因及结构研究奠定基础,对贵阳市某宠物医院犬瘟热病毒金标卡检测呈阳性病死犬的肝脏、肺脏、淋巴结等组织,取适量经混合研磨过滤后,同步接种于Vero传代细胞上进行病毒分离培养,并对该分离毒株进行理化特性、电镜形态、血清学和核酸检测等系列鉴定。结果表明:在Vero细胞上盲传至第6代时稳定出现特征性的CPE,该毒株为RNA囊膜病毒,电镜下可见胞浆包涵体、病毒粒子呈晶格状排列,病毒可被犬瘟热阳性血清中和,分离病毒为犬瘟热病毒并被命名为CDV-GZ1株。