电子供体及受体对棕色固氮菌抗氨阻遏能力的影响

电子供体连二亚硫酸钠,甲基紫精及电子受体亚甲蓝均能强烈的抑制棕色固氮菌表达固氮活性,并引起该菌的抗氨阻遏能力减弱,适当提高氧压,能提高菌体的固氮活性近15％,但过高的氧分压反而抑制菌体的固氮活性,此外,提高氢分压能降低棕色固氮菌菌体内的还原电位,从而达到提高菌体抗氨阻遏能力的效果。     

电子供体及受体对棕色固氮菌抗氨阻遏能力的影响*

电子供体连二亚硫酸钠、甲基紫精及电子受体亚甲蓝均能强烈抑制棕色固氮菌表达固氮活性 ,并引起该菌的抗氨阻遏能力减弱。适当提高氧压 ,能提高菌体的固氮活性近1 5 % ,但过高的氧分压反而抑制菌体的固氮活性。此外 ,提高氢分压能降低棕色固氮菌菌体内的还原电位 ,从而达到提高菌体抗氨阻遏能力的效果。     

米曲霉木聚糖酶生产菌的理性选育及发酵优化

目的：米曲霉木聚糖酶生产菌的理性选育及发酵优化。方法：以米曲霉FS018为出发菌株,采用紫外和激光诱变先后处理3代,以抗高浓度葡萄糖阻遏效应为筛选模型获得一株高产木聚糖酶菌株FST036,并对该菌株的发酵培养基进行了初步优化。结果：突变株FST036产酶水平可达4200．57U／mL,产酶水平比出发菌株提高了24％。对该菌株的发酵培养基初步优化结果表明：培养基的最适氮源为牛肉膏;最适碳源为麸皮与玉米芯组合,总浓度为4％。二者最适比例为7：3;对该菌株的发酵条件初步优化结果表明：最适接种量1％,初始pH6．78,250mL三角瓶装液量为45mL,培养72h酶活可达5404．24U／mL。结论：反复多次诱变处理,并结合抗高浓度葡萄糖阻遏效应作为一种理性筛选模型,为通过诱变育种来获得曲霉木聚糖酶高产菌株提供了一条有效的途径。     

高产脂肪酸菌株的诱变筛选

本文研究了无花果丝孢酵母（Ｔｒｉｃｈｏｓｐｆｉｇｕｅｒｉａｅ）Ｊ—０４等６株微生物的脂肪酸在细胞内、细胞外及细胞表面的分布。用紫外线和硫酸二酯对Ｊ－０４进行复合诱变。用制霉菌素和琥珀酸钠筛选具有高渗透性和抗阻遏的突变菌株。诱变筛选的ＪＵ－０９菌株,其胞外酶活性提高了７６％。     

黄孢原毛平革菌抗营养阻遏产漆酶诱变育种及其产酶特性

【目的】筛选能抗营养阻遏产漆酶的黄孢原毛平革菌,论证其产漆酶的确定性及抗营养阻遏产木质素酶的可行性,为白腐菌产酶代谢调控、木质素降解机理的研究奠定基础。【方法】利用重复紫外诱变法,以愈创木酚富氮鉴别培养基筛选目标菌株;比较不同营养条件下菌体生长与产酶动力学差异研究产酶营养调控机理;通过热处理、排除锰离子和加入过氧化氢酶等不同措施论证黄孢原平毛平革菌能否产生漆酶。【结果】3种不同方法均证实选育到的pcR5305和pcR5324菌株在限氮与富氮条件下均能产生漆酶,pcR5305和pcR5324在限氮条件下产漆酶分别达到203.5、187.6 U/L;在富氮条件下为220.6、183.9 U/L,而原菌株pc530在两种条件下都基本不产生漆酶。二菌株产漆酶调控方式不同,pcR5305漆酶产生与菌体生长同步,而pcR5324漆酶产生却受营养氮阻遏。二菌株同时具有抗营养阻遏高产木质素过氧化物酶(LiP)和锰过氧化物酶(MnP)(分别为LiP 1343.2、MnP 252.2 U/L;LiP 1169.5、MnP 172.4 U/L)的能力。【结论】筛选到的黄孢原毛平革菌变异菌株能产漆酶,同时表现了抗营养阻遏产漆酶、木质素过氧化物酶和锰过氧化物酶的能力,具有重要的生产应用与理论研究价值,为白腐菌产酶代谢调控机理研究提供了原始菌株并奠定了良好的基础。     

尼日利亚菌素高产菌株的选育

通过对致死率和正负突变率的测定,确定了紫外线、亚硝酸、紫外线加吖啶橙3种诱变方式对吸水链霉菌NND-52的29号菌株进行诱变处理的合适剂量,并采用复合诱变得到了一株脱葡萄糖阻遏的高产菌株A19,其尼日利亚菌素的摇瓶产量比出发菌株提高了128％。传代结果表明,在传代的同时结合自然分离,可以保持稳定的产抗特性。     

快速筛选产β—葡聚糖酶曲霉及抗阻遏育种

采用改良琼脂块鉴定平板法进行产β-葡聚糖酶曲霉的快速筛选。其中温度、初始pH、平板厚度及去氧胆酸钠的浓度都影响曲霉产β－葡聚糖酶分解底物所形成水解圈大小及透明度。同时研究发现,高浓度的葡萄糖对曲霉合成β－葡聚糖酶具有阻遏作用,通过改变分离培养基的葡萄糖浓度,结合诱变育种可以快速筛选到抗葡萄糖阻遏的高产β－葡聚糖酶的菌株。     

氮源对钝齿棒杆菌谷氨酰胺合成酶的调节作用及溶菌酶对破壁作用…

钝齿棒杆菌６２８２谷氨酰胺合成酶的合成显著受氮源性质的影响,以５０ｍｍｏｌ／Ｌ谷氨酸钠为唯一氮源时,谷氨酰胺合成酶活力最高;ＮＨ４＾＋对谷氨酰合成酶的合成有阻遏作用,谷氨酸钠则具有解阻遏作用,蛋清溶菌酶对于菌株６２８２的细胞超声波破碎具有良好的辅助作用,适宜的细胞破碎条件为０．８ｍｇ／ｍｌ溶菌酶,３７℃保温４￣５ｈ,超声波１２０Ｗ处理１２ｍｉｎ。     

酿酒酵母(Saccharomyces cerevisiae)半乳糖可诱导表达系统特性的研究

把大肠杆菌β-半乳糖苷酶基因克隆到带有酵母半乳糖可诱导启动子GAL1的穿梭表达质粒pYESZ中,并把得到的重组质粒分别转化到两种不同遗传性状的宿主菌中,其中一株菌为蛋白酶活性缺失90％以上的pep4－3突变菌株。通过比较两株重组菌产生的β-半乳糖苷酶活性水平发现在所述实验条件下,蛋白酶缺失突变菌株中产生的β-卜半乳糖苷酶活水平不仅均要高于另一对照菌株,并且pep4-3突变菌株表现出受葡萄糖阻遏的严紧程度高及对诱导反应迅速等特点。此外,带有重组质粒的pep4－3突变菌株在葡萄糖阻遏培养基中最大生长量和重组对照菌株基本相同,但β-半乳糖苷酶在pep4－3突变菌株中的表达对细胞生长的影响明显小于对照菌株。     

嗜碱芽孢杆菌NTT33产碱性β-甘露聚糖酶发酵条件的研究及高产菌株选育

研究了嗜碱芽孢杆菌（ａｌｋａｌｏｐｈｉｌｉｃＢａｃｌｕｓｓｐ．）ＮＴＴ３３发酵产生胞外碱性β－甘露聚糖酶的条件,其最佳碳源为１％槐豆角,最佳氮源为１％蛋白胨＋０．２％酵母膏,发酵培养３６ｈ产酶量最高（达６１．３υ／ｍＬ）。甘油,葡萄糖,甘露糖等对产酶有强的阻遏作用。该菌株经紫外诱变处理后,采用透明圈法初步筛选出在含葡萄糖和不含葡萄糖的槐豆胶培养基上同时产生透明圈的菌株,进一步测定其产酶进程曲线,最后筛选到一株（ＮＴＴ３３－ｒ６）部分消除葡萄糖代谢阻遏高产β－甘露聚糖酶的菌株,其酶活力比出发菌株提高５０％,,达到９６．３Ｕ／ｍｌ;。     

Exercise-induced hormone responses in girls at different stages of sexual maturation

The dependence of exercise-induced hormone responses on sexual maturation was tested in a 3-year longitudinal experiment on 34 girls (aged 11–12 years at the beginning). Sexual maturation was evaluated by Tanners five-stage scale. Children cycled for 20-min at 60% maximal oxygen uptake once a year. Cortisol, insulin, growth hormone, β-oestradiol, progesterone and testosterone concentrations in venous blood were determined by radioimmunoassay procedures. Basal concentrations of growth hormone increased and of cortisol decreased when breast stage III was reached. Reaching breast stage IV was associated with an increase in basal concentrations of β-oestradiol, progesterone and testosterone. The exercise induced significant increases in concentrations of cortisol, growth hormone and β-oestradiol and a decrease in insulin concentration. At breast stage III the increase in cortisol concentration was to a lower level [467 (SEM 42) vs 567 (SEM 46)nmol · l⁻¹] and growth hormone concentration to a higher level [29.4 (SEM 0.5) vs 12.8 (SEM 0.4)ng · ml⁻¹], while the fall in insulin concentration was less pronounced [postexercise level 10.6 (SEM 0.9) vs 7.8 (SEM 0.8)mU · l⁻¹] than in stage II. The magnitude of the cortisol response was reduced in the last stage of breast development (+42.1% vs +55.5% at stage II, +66.2% at stage III, and +50.0% at stage IV). The magnitude of β-oestradiol response was the lowest in breast stage IV (+15.8%) and the highest at stage V (+41.1%). The progesterone response became significant at stage IV and testosterone response at stage V. In conclusion, we found that reaching breast stage III was associated with altered responses of cortisol, insulin and growth hormone concentrations while the responses of the sex hormone concentrations became pronounced in the last stages of sexual maturation. Accepted: 17 September 1997     

Rethinking the deserving body: altruism,markets, and political action in health care provision

Abstract

I seek to understand two dimensions in the evolution and practices of medical institutions in the USA. First, I ask, how and why do medical organizations limit, suspend, or redirect profit-oriented functions to abide by principles of altruism and still survive in a competitive market economy? Reaching out to poor and immigrant populations entails non-economic factors, including the deployment of religious and humanitarian narratives. Conversely, the extent and character of legislative actions supporting philanthropic endeavours is closely related to mobilization at the grassroots level. I investigate the ways in which community organizations bring about changes to support practices that confound, at least to some extent, market expectations and underscore the significance of political action to secure health care services on behalf of low-income populations, including immigrants.     

关于苏北地区某三甲医院进口与国产医疗设备和耗材使用情况及反馈的研究．

目的：初步了解了进口与国产医疗设备与耗材的发展状况和使用反馈情况,并对国内医疗设备与耗材行业的发展提供合理化建议。方法：通过对苏北地区某三级甲等医院设备科工作人员、医生、护士长、患者及患者家属进行调研或访谈,并以调研和访谈的统计结果为依据得出结论并提出建议。结果：技术成熟的中小型医疗设备或耗材,从质量、价格等因素综合考虑,国内产品优于进口产品,一定程度上得到了医务人员和消费者的认可。在高端大中型医疗设备与耗材方面,进口产品具有较大的技术优势。结论：国内医疗设备生产企业应当积极开展研发工作,提高产品的技术含量与质量,巩固自身在中小型医疗设备与耗材方面的优势,并努力在高端大中型医疗设备与耗材方面取得突破。     

关于苏北地区某三甲医院进口与国产医疗设备和耗材使用情况

目的:初步了解了进口与国产医疗设备与耗材的发展状况和使用反馈情况,并对国内医疗设备与耗材行业的发展提供合理化建议。方法:通过对苏北地区某三级甲等医院设备科工作人员、医生、护士长、患者及患者家属进行调研或访谈,并以调研和访谈的统计结果为依据得出结论并提出建议。结果:技术成熟的中小型医疗设备或耗材,从质量、价格等因素综合考虑,国内产品优于进口产品,一定程度上得到了医务人员和消费者的认可。在高端大中型医疗设备与耗材方面,进口产品具有较大的技术优势。结论:国内医疗设备生产企业应当积极开展研发工作,提高产品的技术含量与质量,巩固自身在中小型医疗设备与耗材方面的优势,并努力在高端大中型医疗设备与耗材方面取得突破。     

Hiatal surfaces from the Miocene Globigerina Limestone Formation of Malta: Biostratigraphy, sedimentology, trace fossils and early diagenesis

The Miocene Globigerina Limestone of the Maltese islands contains widespread omission surfaces with very different characteristics and origins.The terminal Lower Globigerina Limestone hardground (TLGLHg) formed during a period of falling sea level. Coccolith assemblages suggest shallowness. Sedimentary structures and trace fossil assemblages, indicate increasing frequency of storm events and erosional episodes, towards the surface. Calcite cementation which took place around Thalassinoides burrows and formed irregular nodules was followed by dissolution of aragonite. It is suggested that lithification was linked to microbial reactions involving organic matter.In contrast two later surfaces, the terminal Middle Globigerina Limestone omissionground (TMGLOg), which marks the Lower to Middle Miocene boundary, and the Fomm-ir-Rih local hardground (FiRLHg) both contain early diagenetic dolomite. Lithification took place in two phases. The dolomite is interpreted to have formed beneath the sea floor; it was subsequently exhumed and partially corroded as the precipitation of calcitic and phosphatic cements took place around burrows open to the circulation of sea water.     

Comparative study of major lipid constituents in human and monkey aorta

The contents of total lipids, phospholipids, cholesterol, triglyceride and free fatty acid in intima and media of thoracic and abdominal segments of aorta from normal human subjects and rhesus monkeys were determined. An increase in total lipids in intima as compared to that of media was noted in both species. A comparison of lipid contents of thoracic and abdominal segments from both species revealed that abdominal segment contained significantly greater lipid. Further, human thoracic and abdominal aortic intima and media had higher content of cholesterol as compared to that of monkey aorta. The differences in lipid profile in aorta of these two species have been highlighted to provide a clue with respect to the differences in the prevalence and morphology of atherosclerosis as seen in monkey and man.     

论＂医德＂的基本范畴

医德是医疗卫生领域精神文明建设的重要部分,也是调整医务人员与病人、医务人员之间以及与社会之间关系的行为准则。医德范畴是指人们对现代医务人员职业道德和医患关系的总结,它不仅概括了医生所应履行的职责义务,而且反映着一段时间内医患关系的本质。本文通过对医德范畴内,医生的权利和义务、责任和良心、功力和荣誉、审慎和保密四类问题的阐述,探讨当下医生在工作中应该保持何种心态,如何与患者进行沟通,以期更好地提供医疗服务。     

植物引种驯化研究概述

植物引种驯化是植物学的一个分支学科,该学科与植物的迁地保护和当地的经济建设紧密相关,属于应用基础研究的范畴。但有关理论和方法的研究至今仍显得比较零碎,不够系统,判断植物引种驯化成功的标准尚不够明确。本文就植物引种驯化的概念和意义、主要理论和方法、影响其成败的因子、途径和程序、判断植物引种驯化成功的标准等进行了综述和探讨,并提出了植物引种驯化的展望。