Dynamic expression of a cell-surface determinant ofCandida albicans

Penicilliosis marneffei has emerged as an endemic systemic mycosis in Southeast Asia among humans and wild bamboo rats. To gain an insight into the epidemiology of this life-threatening disease, a survey of bamboo rats for natural infections byPenicillium marneffei was carried out in the central plains of Thailand during June-September, 1987. Thirty-one lesser bamboo rats (Cannomys badius) and eight hoary bamboo rats (Rhizomys pruinosus) were trapped. Portions of their internal organs were cultured to determine if they had been infected byP. marneffei. Six each ofC. badius (19.4%) andR. pruinosus (75%) yielded cultures of this unique, dimorphicPenicillium species. All of the isolates were readily converted to their unicellular form that multiplies by the process of schizogony by incubating them at 37 °C on plates of brain heart infusion agar. Their identity was further confirmed by a specific immunological test. Among the internal organs of the positive rats, the lungs had the highest positivity (83.3%), next in decreased order of frequency were the liver (33.3%) and the pancreas (33.3%). The use and value of domestic and wild animals in locating and demarcating endemic areas of geophilic fungal pathogens are discussed. Penicilliosis marneffei is considered to be a zooanthroponosis — a disease that occurs in lower animals, as well as, humans.     

Radiation induced angiosarcoma a sequela of radiotherapy for breast cancer following conservative surgery

Radiation induced angiosarcomas (RIA) can affect breast cancer patients who had radiotherapy following conservative breast surgery. They are very rare tumors and often their diagnosis is delayed due to their benign appearance and difficulty in differentiation from radiation induced skin changes. Therefore it is very important that clinicians are aware of their existence. We report here a case of RIA followed by discussion and review of literature.     

Novel strategy in Trypanosoma cruzi cell invasion: implication of cholesterol and host cell microdomains

Trypanosoma cruzi, the etiological agent of Chagas' disease, is an obligatory intracellular parasite in the mammalian host. In order to invade a wide variety of mammalian cells, T. cruzi engages parasite components that are differentially expressed among strains and infective forms. Because the identification of putative protein receptors has been particularly challenging, we investigated whether cholesterol and membrane rafts, sterol- and sphingolipid-enriched membrane domains, could be general host surface components involved in invasion of metacyclic trypomastigotes and extracellular amastigotes of two parasite strains with distinct infectivities. HeLa or Vero cells treated with methyl-beta-cyclodextrin (MbetaCD) are less susceptible to invasion by both infective forms, and the effect was dose-dependent for trypomastigote but not amastigote invasion. Moreover, treatment of parasites with MbetaCD only inhibited trypomastigote invasion. Filipin labeling confirmed that host cell cholesterol concentrated at the invasion sites. Binding of a cholera toxin B subunit (CTX-B) to ganglioside GM1, a marker of membrane rafts, inhibited parasite infection. Cell labeling with CTX-B conjugated to fluorescein isothiocyanate revealed that not only cholesterol but also GM1 is implicated in parasite entry. These findings thus indicate that microdomains present in mammalian cell membranes, that are enriched in cholesterol and GM1, are involved in invasion by T. cruzi infective forms.     

蟋蟀脑的解剖结构与生理机能

蟋蟀脑由前脑、中脑和后脑三部分组成。前脑由1对蕈形体、中央复合体和视叶构成;每个蕈形体由2个冠、柄及与柄相连的α叶和β叶组成,是信息联络整合部位;中央复合体由中央体和脑桥组成,主要参与感觉信息的加工过程;视叶由神经节层、外髓和内髓组成,是视觉系统的中心。中脑由主要组成成分为嗅觉纤维球的嗅叶组成,是嗅觉系统的中心。后脑向后与食道下神经节相连。     

电场对油葵种子苗期干旱胁迫后生长的影响

用不同电场强度处理油葵种子,在田间和实验室测定电场处理种子对苗期干旱胁迫后生长的影响。研究结果表明,种子经电场处理,可明显提高油葵生长的抗旱能力。在０．５ｋＶ／ｃｍ－６．０ｋＶ／ｃｍ场强范围内,不同电场强度对其生长的影响程序不同。与对照组相比,田间出苗率提高４．１１％￣２８．０％,根冠比提高６．６０％￣３８．７％,植株萎蔫程度降低５．０％￣９５％,产量提高３．４０％￣１７．９％,含油率提高１．０３     

Ag85ADNA疫苗对荷瘤鼠Th1细胞免疫功能的影响

为了探讨肌肉注射Ag85A DNA疫苗能否在肿瘤宿主,一个低细胞免疫应答的机体内激发Th1型细胞免疫应答,将6~8周龄BALB/c雌性小鼠随机分成实验组(Ag85A-V1Jns.tPA组),空质粒组(V1Jns.tPA组)和生理盐水组3组,将生长旺盛的Meth-A细胞接种于各组小鼠右侧背部皮下,每只小鼠2×105个细胞,1d后于小鼠大腿肌肉内分别注射100μL Ag85A-V1Jns.tPA(1 g/L),V1Jns.tPA(1 g/L)或生理盐水。每10 d 1次,共3次,于末次注射后第8 d,无菌取脾,分离细胞进行培养。检测NK细胞活性以及脾细胞培养上清中IFN-γ含量。结果显示:实验组平均NK细胞杀伤率以及脾细胞培养上清中IFN-γ含量较空质粒组和生理盐水组均显著增高,而空质粒组和生理盐水组之间未见有意义的变化。提示肌肉注射Ag85A DNA疫苗可以提高Meth-A纤维肉瘤荷瘤小鼠Th1细胞免疫功能。     

MAGE-A1,A2,A3,A4在膀胱移行细胞癌组织及细胞株中基因表达的研究

目的研究膀胱移行细胞癌(TCC)中黑色素瘤抗原(MAGE)基因表达。方法逆转录聚合酶链反应(RT-PCR)技术检测20例膀胱TCC患者癌组织和3株膀胱TCC细胞株T24、EJ、BIU87中MAGE-A1、A2、A3、A4基因mRNA表达。结果20例膀胱TCC癌组织中19例(95%)至少表达一种MAGE-A基因,12例MAGE-A1阳性(60%),16例MAGE-A2阳性(80%),11例MAGE-A3阳性(55%),18例MAGE-A4阳性(90%),MAGE-A1-4均阳性8例(40%)。膀胱TCC细胞株T24中MAGE-A1-4基因均表达,EJ中MAGE-A3、A4基因表达,BIU87中MAGE-A2、A3、A4基因表达。结论MAGE基因在膀胱TCC中有较高表达,可望成为膀胱TCC免疫治疗的靶基因。     

植物逆境胁迫耐受性启动子的研究进展

逆境胁迫如干旱、极端温度、损伤等非生物胁迫和病虫害等生物胁迫严重影响植物的生长发育及产量。逆境胁迫耐受性启动子能够接受逆境条件下的诱导信号,激活植物体内胁迫应答基因的表达,使植物感知并适应逆境。本文对逆境胁迫耐受性启动子的克隆及功能研究情况进行综合分析,主要包括抗旱、耐盐、耐高温、抗冻、耐损伤、抗病和抗虫基因启动子。     

陕西省主要蔬菜产区蔬菜重金属污染状况分析与评价

以GB18406．1-2001无公害蔬菜标准为评价依据．对陕西省8个蔬菜主产区的127个蔬菜样品中汞、砷、铅、镉和铬5种重金属污染状况进行分析评价。结果表明,陕西省主要蔬菜产区蔬菜重金属污染以铅污染为主。茄果类和瓜菜类蔬菜铅污染严重,绿叶类蔬菜铅污染相对较轻．其它4种重金属污染未超过国家标准,其中各产区均未检出镉。铅污染程度的大小顺序足成阳秦都〉宝鸡岐山蔡家坡〉汉中汉台〉渭南临渭。成阳泾阳、宝鸡太白、汉中城固、渭南大荔蔬菜产区5种蓖金瞒均未超标．具备发展无公害蔬菜生产基地条件。