极端酶的研究进展

极端酶具有超常的生物学稳定性,能够在极端温度、pH、压力和离子强度下表现出生物学活性,因此极端酶为生物催化和生物转化提供了良机.新的极端物种的发现、基因组序列的确定及基因工程技术的应用,加快了发现和制备新酶的进程.蛋白质工程和定向进化技术进一步改善酶的活性和特异性,促进了极端酶的工业应用.对极端酶的研究加深了人们对酶稳定性机制的理解,丰富了分子进化理论.     

嗜极菌的极端酶

近年来,嗜极菌极端酶的分离鉴定取得了很大进展。本文简述了极端酶的分离纯化及其某些生化特性、极端酶的稳定因素和应用。极端酶的发现与研究,拓宽了传统的生物催化及应用的范围。但是,关于极端酶的稳定机制及其工业应用,仍有许多难题需要解决。     

嗜极菌的极端酶

近年来,嗜极菌极端酶的分离鉴定以得了很大进展,本文简述了极端酶的分离纯化及其某些生化特性,极端酶的稳定因素和应用。极端酶的发现与研究,拓宽了传统的生物催化及应用的范围,但是,关于极端酶的稳定机制及其工业应用,仍有许多难题需要解决。     

海洋微生物纤维素酶及半纤维素酶基因克隆与表达研究进展

海洋极端酶因在极端环境中具有更高的酶活性及更好的稳定性而具有重要的理论价值和工业应用前景。由于海洋极端微生物培养条件苛刻,难以作为工业生产菌使用。采用基因工程技术,用常用的宿主表达极端酶基因,是开发海洋微生物酶的主要研究内容。随着海洋微生物极端酶的研究开发,对海洋微生物纤维素酶、半纤维素酶的研究也逐渐受到学者们的关注,相关研究取得了较大进展。综述海洋微生物纤维素酶、半纤维素酶的基因克隆与表达的国内外研究现状。     

极端酶及其工业应用

无论是从极端环境中筛选天然极端酶,还是由蛋白质工程构建的突变酶,或者是交联酶晶体,都可以提高酶夺环境的抵卸能力及其稳定性,从而使酶在工业上的应用有了突破性的进展。     

作为人造极端酶的交联酶晶体

作为人造极端酶的交联酶晶体林影卢荣德郭勇（华南理工大学生物工程系,广州５１０６４０关键词交联酶晶体极端酶酶作为生物催化剂,催化效率高,立体选择性和底物专一性强,是普通化学催化剂所不可比拟的。然而,在酶的应用过程中还有很多令人不满意之处,如在环境中常常...     

极端微生物及其应用研究进展

极端微生物是指在高/低温、高/低p H、高盐、高压等极端环境条件下生存的微生物.特殊的生存条件导致其具有特殊的遗传背景和代谢途径,并可产生功能特殊的酶类和活性物质.随着系统生物学和合成生物学技术的发展,极端微生物作为一类特殊的微生物群体,在生物医疗、生物能源和生物材料等领域具有巨大的应用潜力.极端微生物相关研究也对生命起源与演化、生物工程技术等领域的发展具有重大意义.本文对极端环境及极端微生物的概念和分类进行了回顾,综述了极端微生物在不同环境条件下的适应机制及其酶的应用,并介绍了合成生物学在极端微生物研究中的应用情况.此外,由于极端微生物和极端酶的特殊性和高效性,本文还探讨了极端微生物开发过程中的挑战,以及其在航空航天与国防安全领域的综合应用潜力,并指出了相关研究的必要性.     

嗜高温酶研究进展

生存于极端环境中的微生物称为极端微生物,其体内的酶称为极端酶。极端环境包括：（１）温度高于８０℃,如陆上地热喷泉和深海底热喷口;年均气温低于零度,如南北极地区。（２）压力巨大,如几千米深的海底。（３）ｐＨ＜２,如煤沉积层和富含硫的地热喷泉;ｐＨ＞１１...     

海洋微生物纤维素酶的研究进展及其应用

海洋极端酶因在极端环境中具有更高的酶活性及更好的稳定性,因而具有重要的理论价值和工业应用前景.随着海洋微生物极端酶的研究开发,海洋微生物纤维素酶的研究也逐渐受到学者们的关注,并取得了较大进展.综述迄今为止分离出的产纤维素酶的海洋微生物种群及其酶学特性,海洋微生物纤维素酶基因克隆与表达的国内外研究现状,分析海洋微生物纤维素酶潜在的应用价值及未来发展前景.     

极端微生物：一种新型的酶资源

极端微生物具有自身独特的特点和代谢产物 ,在食品工业、化工、药用工业和环境生物技术领域都有潜在的应用。一些酶已经得到纯化 ,其基因在宿主中已成功克隆。主要介绍和讨论极端微生物的类型、基因组及极端酶类的生产、分离与应用。     

Seasonal patterns in feeding ecology of three small fishes in the Biandantang Lake, China

Feeding ecology of three small fish species, Hypseleotris swinhonis, Ctenogobius giurinus and Pseudorasbora parva was studied seasonally in the Biandantang Lake, a small, shallow lake in central China. Gut length, adjusted for total body length, was significantly higher in spring than in other seasons for all the three species. Seasonal changes in gut length were not associated with changes in food quality. Weight of fore-gut contents, adjusted for body weight, was significantly higher in winter and spring than in summer and autumn in H. swinhonis and C. giurinus , and significantly higher in autumn than in spring and summer for P. parva. Percentage of empty fore-guts was highest in summer and lowest in spring for H. swinhonis and C. giurinus , and highest in winter and lowest in autumn for P. parva. Diet of the three small fishes showed apparent seasonal changes, and these changes reflected partly the seasonal fluctuations of food resources in environment. Diet breadth was high in winter and low in autumn for H. swinhonis , high in winter and low in spring and summer for C. giurinus , and high in autumn and low in spring for P. parva. Diet overlaps between pairs of species were biologically significant in most cases, except between H. swinhonis and P. parva in summer and autumn and between C. giurinus and P. parva in autumn.     

Species and individual differences in juvenile female alloparental care are associated with oxytocin receptor density in the striatum and the lateral septum

The neuropeptide oxytocin has been implicated in the regulation of affiliative behavior and maternal responsiveness in several mammalian species. Rodent species vary considerably in the expression of juvenile alloparental behavior. For example, alloparental behavior is spontaneous in juvenile female prairie voles (approximately 20 days of age), takes 1-3 days of pup exposure to develop in juvenile rats, and is nearly absent in juvenile mice and meadow voles. Here, we tested the hypothesis that species differences in pup responsiveness in juvenile rodents are associated with oxytocin receptor (OTR) density in specific brain regions. We found that OTR density in the nucleus accumbens (NA) is highest in juvenile prairie voles, intermediate in juvenile rats, and lowest in juvenile mice and meadow voles. In the caudate putamen (CP), OTR binding was highest in prairie voles, intermediate in rats and meadow voles, and lowest in mice. In contrast, the lateral septum (LS) shows an opposite pattern, with OTR binding being high in mice and meadow voles and low in prairie voles and rats. Thus, alloparental responsiveness in juvenile rodents is positively correlated with OTR density in the NA and CP and negatively correlated with OTR density in the LS. We then investigated whether a similar receptor-behavior relationship exists among juvenile female prairie voles by correlating individual variation in alloparental behavior with variation in OTR density. The time spent adopting crouching postures, the most distinctive component of alloparental behavior in juveniles, was positively correlated with OTR density in the NA (r = 0.47) and CP (r = 0.45) and negatively correlated with OTR density in the lateral septum (r = -0.53). Thus, variation in OTR density in the NA, CP, and LS may underlie both species and individual differences in alloparental care in rodents.     

啮齿动物作用下退耕地山杏种子扩散与贮藏的季节变化

啮齿动物对植物种子的取食和扩散影响种子的时空分布,继而影响种子的萌发和幼苗建成,因而在森林更新中起着重要作用.在国有济源市愚公林场,选择退耕地生境,于春季、夏季、秋季分别释放人工标记的山杏种子,观察啮齿动物扩散与埋藏山杏种子的季节性差异.结果表明：1）退耕地中的啮齿动物主要包括大林姬鼠、社鼠、黑线姬鼠;2）山杏种子扩散速率在春季显著慢于夏季,夏季显著慢于秋季;3）种子搬运量受季节和种子状态交互作用影响,春季显著少于夏季,夏季显著少于秋季;4）不同季节种子平均搬运距离不同,秋季不同状态种子的搬运距离均大于春季和夏季;5）啮齿动物对山杏种子的贮藏点大小多为1粒种子,少量为2、3粒种子,且贮藏点大小与季节间存在显著的交互作用,春季单粒种子的贮藏点数量显著少于夏季和秋季,而夏季与秋季的贮藏点则倾向于多粒种子;6）在夏季和秋季各有5枚（共释放1800枚）被啮齿动物分散贮藏的山杏种子建成幼苗.     

国人睾丸、附睾和输精管的氧化还原酶的组织化学观察

本文收集了１９—３８岁国人正常男性新鲜睾丸、附睾和输精管１３例,进行了氧化还原酶组织化学染色、光镜定位及定性观察。结果表明：睾丸曲细精管和输出小管上皮的ＧＤＨ,ＮＡＤＨＤ,ＮＡＤＰＨＤ,ＳＤＨ,ＧＰＤＨ,ＩＣＤＨ,ＭＤＨ,ＬＤＨ和Ｇ－６－ＰＤＨ９种酶;睾丸间质细胞和附睾管上皮的ＮＡＤＨＤ,ＮＡＤＰＨＤ,ＳＤＨ,ＩＣＤＨ,ＭＤＨ,ＧＤＨ,ＬＤＨ和Ｇ－６－ＰＤＨ８种酶;输精管的ＮＡＤＨＤ,ＮＡＤＰＨＤ,ＩＣＤＨ和ＧＤＨ４种酶的酶活性呈强阳性或极强阳性。提示输出小管和头部附睾管含有的多种氧化还原酶对精子功能成熟有极重要作用。     

社鼠组织器官同工酶的研究

用聚丙烯酰胺凝胶等电聚焦电泳方法,分析了社鼠的肝、肾、心肌、骨骼肌、肺、脾和脑等多种组织器官的ＬＤＨ、ＡＤＨ、ＥＳＴ、和ＳＯＤ４种同工酶,对各组织器官的酶带数目和分布,以及酶活性进行了比较研究。结果表明,社鼠的ＬＤＨ同工酶、ＡＤＨ同工酶和ＥＳＴ同工酶具有比较明显的组织特异性,而ＳＯＤ同工酶的组织特异性较低。肺和脾除ＥＳＴ同工酶活性较高外,脑除ＬＤＨ同工酶活性较高外,其它３种同工酶的活性均较低;而肝和肾中４种同工酶的活性普遍很高。心肌和骨骼肌因氧张力不同而使ＬＤＨ同工酶酶谱存在明显差异,但其它３种同工酶酶谱却非常相似。同工酶的组织特异性与各组织器官所执行的生理功能是相一致的     

Influence of glucocorticoids on time-of-day-dependent variations in IgE-, histamine-, and platelet-activating factor-mediated systemic anaphylaxis in different mouse strains

A time-of-day-dependent variation in IgE-mediated passive systemic anaphylaxis was previously reported in ICR mice. In the present study, we investigated time-of-day-dependent variations in IgE-, histamine-, and platelet-activating factor (PAF)-mediated systemic anaphylaxis in C57BL/6, BALB/c, and NC/Nga mice at 9:00?h and 21:00?h, and evaluated the potential influence of glucocorticoids (GCs) on these variations. We found significant time-of-day-dependent variations in IgE-mediated systemic anaphylaxis in C57BL/6 mice, and in histamine- and PAF-mediated systemic anaphylaxis in BALB/c mice. Significant daily variations in IgE-, histamine-, and PAF-mediated systemic anaphylaxis were not observed in NC/Nga mice. Pretreatment with dexamethasone and adrenalectomy abolished the daily variations in IgE-mediated systemic anaphylaxis in C57BL/6 mice and in PAF-mediated systemic anaphylaxis in BALB/c mice, suggesting that GCs from adrenal glands are pivotal in regulating these variations. In contrast, pretreatment with dexamethasone and adrenalectomy did not abolish the daily variation in histamine-mediated systemic anaphylaxis in BALB/c mice, suggesting that GC-independent and adrenal gland-independent mechanisms are important for the variation. The present study demonstrated that time-of-day-dependent variations in systemic anaphylaxis differed among inbred mouse strains and with anaphylaxis-inducing substances. Thus, mouse strains, time of experiment, and anaphylaxis-inducing substances used must be considered to obtain appropriate experimental results.     

Palynology of South Indian Zingiberaceae

MANGALY, J. K. & NAYAR, J. 1990. Palynology of South Indian Zingiberaceae. Light microscope studies on pollen morphology of 21 Old World, tropical taxa of Zingiberaceae reveal that an exine is absent only in Kaempferia . A discontinuous exine layer consisting of circular plates joined together at margins occurs in Alpinia galanga and Amomum hypoleucum while all other taxa possess an uninterrupted exine layer which is commonly 0.7 μm to less than 2.0 μrn thick (3.2 μm in Zingiber zerumbet , 2.5 μm in Amomum hypoleucum ). Exine is spinose in Alpinia (smooth in Alpinia sanderae ), Amomum and Boesenbergia , verrucose in Eleltaria , tuberculate to areolate or striate in Zingiber , papillose in Globba and smooth or nearly so in Curcuma, Costus and Hedychiurn . Pollen grains are spheroidal, 50–90 μm in size (35 μm in Globba ophioglossa ), and inaparturate (foraminate in Costus ), except in Curcuma and Zingiber where they are ovoid to ellipsoidal, 70–135 times 60–80 μm in size and sulcate. A lamellated intine, much thicker than the exine, occurs in all, and it is thinner at the apertural region in Curcuma, Costus and Zingiber; in Elettaria and Hedychiurn it is thinner in one or few large scattered circular areas, and in Boesenbergia and Alpinia zerumbet on one side of the grains. Palynologirally Alpinia, Amomum, Boesenbergia, Kaempferia and Zingiber constitute one group while Elettaria, Hedychiurn and Costus constitute another.     

安蕨属的分类与分布

1849年,捷克人Presl根据菲律宾产的一种蕨类植物Anisocampium cumingia-num Presl,建立了安蕨属Anisocapium Presl,几十年来未被各国植物学家(如Baker、Beddom、Makino、C.Christensen、Christ、Nakai、秦仁昌、Devol、Ohwi和Tagawa)所承认。1940年,Tard.-Blot et C.Chr.编写《印度支那植物通志》(Fl.Gen.Indo-Chine)时接受了安蕨属的概念。1947年,美国人Copeland研究东南亚蕨类植物时,也肯定了安蕨属是一个自然分类群。以后,     

猪激素敏感脂酶和甘油三酯水解酶基因组织表达特性研究

以八眉猪为研究对象,采用RT-PCR和Western blot方法对猪激素敏感酯酶(HSL)和甘油三酯水解酶(TGH)基因组织表达特点进行了研究。RT-PCR半定量检测显示,HSL基因的mRNA在检测的7种组织中都有表达,其中在脂肪组织表达量较高,中等程度表达于心脏、肝脏、肺、脾和肾脏。TGH基因在7种组织也均有表达,其中肝脏和脂肪组织表达量较高,心脏和肾脏次之,脾脏和肺脏表达量较低。Western blot检测显示,HSL基因在大网膜脂肪和皮下脂肪表达量最高,而在肾脏中没有检测到表达,其他组织中中度表达;TGH基因在大网膜脂肪、皮下脂肪、肝脏、肺脏和脾脏组织中表达,其中在脂肪组织和肝脏组织中表达量最高,而在心脏和肾脏中没有检测到表达。以上结果表明:HSL和TGH基因存在转录后调控,这可能与其在不同组织中的功能差异有关。     

Slowmo is required for Drosophila germline proliferation

Null mutations in the Drosophila gene, slowmo (slmo), result in reduced mobility and lethality in first-instar larvae. Slowmo encodes a mitochondrial protein of unknown function, as do the two other homologs found in Drosophila. Here, we have studied a hypomorphic P-element allele of slmo demonstrating its effects on germline divisions in both testes and ovaries. Using in situ studies, enhancer-trap activity, and promoter fusions, we have shown that slmo expression in testes is found in the somatic cyst cells (SCC). The hypomorphic allele for Slmo revealed apoptotic loss of germline cells in the larval germline, culminating in a complete absence of the germline in adult flies. In females, a similar degeneration of the germarium is observed, while reporter gene expression is found in both germline and somatic cells. Using a null mutation in female germline clones, we find slmo is dispensable from the germline cells. Our results suggest that Slowmo is not required in germline cells directly, but is required in SCCs responsible for maintaining germline survival in both sexes.