^137Cs,^134Cs在人工海洋小生境中的行为

在自行建立的人工海洋小生境中,采用示踪法综合地研究~(137)Cs、~(134)Cs在人工小生境中的行为。结果表明,~(137)Cs和~(134)Cs具有共同的生理生态行为,并表现出相似的规律、沉积物对~(137)Cs、~(134)Cs的吸附能力甚低,~(137)Cs、~(134)Cs在海洋动物体内趋于全身性的分布。各主要生化物质均能检出~(137)Cs、~(134)Cs。排泄实验后,海洋动物的胃肠、肝(消化腺)~(137)Cs、~(134)Cs损失显著。沉积物表现为解吸-重吸附的过程。     

扁藻对~(60)Co、~(137)Cs浓集机理初探

~(60)Co、~(137)Cs是沿海核设施的主要废物之一,其稳定同位素Co和Cs的生物学作用截然不同,前者是生命必需元素,后者是生命非必需元素。因而~(60)Co、~(137)Cs在海洋生物体内的浓集也表现出明显的差别,一般地说,~(60)Co的浓集量大,排出慢;~(137)Cs的浓集量小,排出快。这种差别的机理是什么?作者研究泥蚶的结果表明,泥蚶对~(60)Co的吸收以主动吸收为主,且需要能量的供应,而对~(137)Cs的吸收以被动吸收为主,与能量供应关系不密切。     

~(125)Ⅰ—蜂毒肽在小鼠体内分布、吸收、排泄的研究

以氯胺T为氧化剂参照Hunter和Greenwood的多肽类化合物的碘化标记法,制备了~(125)I—标记的蜂毒肽在小鼠体内分布、吸收、排泄的研究,实验证明小鼠肌注~(125)I—蜂毒肽后,吸收很快,主要分布部位为肾、肺、心、肝、小肠、关节、脾与肌肉,脑组织中含量很少,肌肉注射后5分钟血液中含量可达70％,~(125)—I蜂毒肽主要经肾排泄,肌注后30分钟肾脏浓集最高,而尿液中以1.5小时为最高,而粪便中排泄少。     

乌塘鳢对51Cr、60Co、131I、141Ce的吸收和积累

本文以河口底栖鱼类,不具鳞片,对环境适应力强的乌塘鳢为材料,研究它们以摄食和渗透两种方式对~(51)Cr,~(60)Co、~(131)I和~(141)Ce的吸收。为了观察在渗透吸收期间个体的差异,测定了单条活鱼的放射性。在实验中采用多核素示踪法并用S-80智能多道分析器和Ge(Li)探头测量放射性。 结果发现,当~(131)I的浓度为3.4×10~(-7)居里/升时,在10小时内所有的乌塘鳢都被杀死,而~(131)I在鱼体各组织器官的积累是明显的。器官积累核素数量的顺序是~(131)I>~(141)Ce>~(51)Cr,在任何组织器官均未检出~(60)Co。 在渗透吸收实验里,对单条活鱼的测量结果表明,核素是能够通过皮肤的渗透积累在鱼体内,并且存在个体差异。同时表明,生命元素的同位素如~(131)I,~(60)Co容易渗透到鱼体内部器官,而非生命元素的同位素例如~(141)Ce、~(51)Cr的渗透是慢的。 ~(51)Cr、~(60)Co、~(131)I、~(141)Ce是沿海核设施常见的放射性废物成分,有的是具有生态学意义的核素(Goldberg,1957),随着沿海核电站的不断兴建,它们在河口港湾存在的机会越来越多。虽然海洋鱼类和淡水鱼类对它们的浓集有过报道(Hiyama et al.,1964),但河口生物,特别是河口的底栖鱼类对它们的吸收和积累,则研究甚少。 乌塘鳢是生活在河口滩涂的底栖鱼类,适应于半咸淡的水质,     

曲酸产生菌激光诱变效应的研究

采用经紫外线(UV)、^60Co、亚硝基胍(NTG)复合诱变得到的黄曲霉曲酸产生菌(UCN7—12),进行激光诱变处理。研究证实在经过UV、^60Co、NTG诱变处理后,黄曲霉突变株用He—Ne激光与YAG激光进行诱变处理仍能提高产酸率,其中He—Ne激光辐照处理20min,正变率为12．1％,产量提高约13％。YAG激光辐照处理300sec,正变率16．7％,产量提高18．3％。说明上述两种激光对黄曲霉曲酸产生菌有一定的诱变效应。     

流行性出血热实验动物模型研究Ⅱ~(60)Co辐照金黄地鼠感染EHF后临床指征观察

为建立流行性出血热(EHF)的实验动物模型,在用~(60)Co辐照金黄地鼠增加对EHFV敏感性实验研究的基础上,进行了~(60)Co辅照金黄地鼠感染EHF后的临床指征检测和观察,探讨γ射线处理金黄地鼠作为疾病实验模型的可能性。实验结果证明,EHFV感染~(60)Co辐照的金黄地鼠,可得到一个有死亡、有发病、无症状的全临床类型的感染     

谷氨酸和α-酮戊二酸对鳜生长、脱氨及糖代谢的影响

为探究谷氨酸(Glu)和α-酮戊二酸(AKG)对鳜(Siniperca chuatsi)摄食和氨排泄的影响,实验以鳜[初始体重(26.28±0.99) g]为研究材料,将Glu和AKG分别添加到鳜的基础日粮中(添加量2%),进行了60d的养殖实验,前40d等量投喂,后20d饱食投喂。通过设置对照组、Glu组和AKG组,比较了3种不同饲料饲喂下鳜的摄食与氨排泄差异情况。实验结果表明,在等量饲喂期间添加Glu、AKG显著提高鳜生长和降低饵料系数,且在一定程度上降低鳜的体外氨排泄量。在饱食投喂阶段, Glu、AKG组的血液中的葡萄糖含量增加,肝糖原、肌糖原含量降低。两个投喂阶段结果都表明,饲料中添加谷氨酸和α-酮戊二酸能显著促进鳜脑中npy表达并抑制pomc表达,显著提高蛋白质效率比和特定生长率,增加鱼体体重,促进鱼体生长且降低饲料系数。同时,肝脏中gdh表达及肌肉ampd表达均提高,脱氨代谢供能水平升高,最终导致其氨排泄量升高。此外,饲料中添加Glu和AKG可促进肝脏pepck、g6pase、pk和gk基因表达量增加,糖代谢增强,减少蛋白质的分解供能。综上所述,在饲料中添加谷氨酸和α-酮戊...     

两种单胞藻类对不同浓度的~(60)Co吸收和排出的影响

海洋中的~(60)Co既来自于核武器试验的降落灰,又来自于核反应堆废物的排入。随着核动力舰船和原子能发电站的日益发展,进入局部海域的放射性将不断增加。放射性核素对于人类的潜在危害,也就越来越为人们所关切。~(60)Co是这些放射性废物中一种重要的元素,半衰期为5.26年,能被海洋生物较大量地吸收和累积。所以~(60)Co成为核动力设施排放废物时限制最严的核素之一。     

激光、~(60)Co—r射线对草毒生物效应的研究

本实验用CO_2激光功率密度10.44W/cm~2、3.40W/cm~2,一次10秒及再次6、10、14秒处理草莓、茎尖外植体,可使多数处理的无性后代,产量提高或品质改善。He—Ne激光输出功率10.6mW,原光斑照射30、40秒,也有与CO_2激光相似效应。~(60)Co—r射线吸收剂量193Gy,单独处理及与He—Ne激光30秒复合处理,可改善果实品质,He—Ne激光对~(60)Co—r射线的辐射损伤有修复作用。     

河口潮间带沉积物重金属累积及生态风险评价

于2015年7月份在闽江口鳝鱼滩湿地布设两条样带(T1和T2),并分别选取5个采样点采集沉积物样品。因重金属Co和V对动物和人类会造成一定危害,且闽江河口潮间带Co和V的研究较少,则对其理化性质、Co和V的空间分布特征以及污染程度等进行了研究,旨在为Co和V的污染研究提供参考。结果显示,该沉积物中Co和V的平均浓度分别为15.19 mg/kg、102.94 mg/kg,均高于福建省背景浓度,与其他河口对比,Co和V浓度处于中等水平。Co和V的含量由陆向海方向略有下降。地累积指数法分析得出沉积物中Co含量呈现轻度污染状态,V呈现无污染状态。此外,Co和V的潜在生态危害系数E_r~i分别为7.24—14.85和1.47—4.17,表明潜在生态危害轻微,闽江河口潮间带沉积物中Co和V属于轻度污染。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.