关于一个“基细胞”的疑问

有或没有基细胞是毛鞘藻属(Bulbochaets)与枝鞘藻属(Oedocladium)的区别之一。这里叙述了Mrozinska在其专著(1985)中,将Oedocladium indicum Kama附图(即模式图)上的一个基细胞错误地移置到Oe.PrescottiiIslam上去的情况。     

枝鞘藻属(Oedocladium Stahl,1891)在我国的首次发现

首次报道了作为鞘藻目中三个属之一的枝鞘藻属(Oedocladium),即勃氏枝鞘藻(Oedocladium prescottii)。     

枝鞘藻属(Oedocladium Stahl,1891)在我国的首次发现

首次报道了作为鞘藻目中三个属之一的枝鞘藻属(Oedocladium),即勃氏枝鞘藻(Oedocladium prescottii)。     

并基角毛藻若干分类学疑问的初步探讨

并基角毛藻是硅藻门角毛藻属的典型种类, 以“相邻角毛基部并行融合”作为标志性特征, 但该特征是否稳定, 及如何赋予其分类学价值?尚存较多争议。研究以符合现存并基角毛藻分类标准的藻株作为目标藻株, 采用毛细管显微操作技术从我国沿海代表水域分离藻株, 建立了目标藻株的单克隆培养株系, 利用光学显微镜、扫描电镜和透射电镜分别对其形态学特征进行观察, 同时还扩增了核糖体大亚基编码基因的D1-D3区序列, 并构建系统进化树。综合分析形态学特征和分子系统学数据, 初步得到以下结论: (1)具有相同遗传特征的并基角毛藻株系在“相邻角毛基部并行融合”特征上具有不稳定性, 即“相邻角毛基部并行融合”不能作为并基角毛藻种类的标志性特征; (2)并基角毛藻和洛氏角毛藻作为相似种类, 均显示出较高的物种多样性, 高于目前的认知, 预示着或许存在隐形种或拟隐形种; (3)推测并基角毛藻单胞变型只是并基角毛藻原种的一个生活史阶段, 是并基角毛藻的同种异名, 不宜继续保留其独立的分类学地位。     

中国轮藻植物分布研究

轮藻植物是低等的藻类植物,但其个体较大、高度分化,生殖器官构造复杂,可与高等植物的性器官比较,因此将它们列为独立一门即轮藻门(Charophyta),轮藻门只有一个轮藻科(Characeae)。轮藻植物分布于除南极洲以外的所有大陆,多生于淡水,少数生长在微盐性的水体中,轮藻植物分布与环     

克罗地亚三叠纪粗枝藻组合的述评

对克罗地亚中三叠统和上三叠统的粗枝藻属化石组合的分析,侧重于特定的种和相关化石的地层分布方面。该分析显示这些藻类化石可以用来对这个时间段内的地层的细分。     

支原体污染细胞的处理方法

<正> 在细胞培养技术中,支原体污染细胞系是一常见问题。受污染细胞的生长和代谢均受到影响,在用该细胞作免疫学试验时。就有可能产生异常结果.尤其在单克隆抗体制备中,污染支原体的骨髓瘤或杂交瘤细胞会导致融合失败或抗体分泌能力下降以至丧失。支原体污染细胞的危害之大,研究建立控制支原体污染的方法也就受到学者们的关注。     

山西鞘藻属一新种

山西鞘藻　新种　图1ＯｅｄｏｇｏｎｉｕｍｓｈａｎｘｉｅｎｓｅＹ.Ｊ.ＬｉｎｇｅｔＳ.Ｌ.Ｘｉｅ,ｓｐ.ｎｏｖ.Ｆｉｇ.1Ｓｐｅｃｉｅｓｎｏｖａｐｌａｎｔａｄｉｏｉｃａ,ｎａｎａｎｄｒａ,ｉｄｉｏａｎｄｒｏｓｐｏｒａｅｔｏｏｓｐｏｒａｅｍｅｓｏｓｐｏｒｉｏａｒｅｏ...     

哺乳动物基础代谢率的主要影响因素

综述了影响哺乳动物基础代谢率的主要因素, 包括体重、系统发育、食性、气候和栖息地、季节、生活习性和繁殖, 以及激素、器官、线粒体和质子漏的理化特征等, 并对这些因素可能的作用机理进行了简要的分析。     

ND^＋3YAG激光治疗基底细胞癌应用研究

YAG激光主要通过它的热效应和对组织穿透深、止血效果好,在临床上起重要治疗作用,因具有封闭小静脉、小动脉及淋巴管的作用,从而防止了癌细胞扩散转移的不良因素。 本文十三例基底细胞癌,其中二例低分化鳞癌属于高恶,术后经二至六年随访至今健在,未发现复发和转移。实践证实,掌握好激光功率大小和正确的治疗方法也是提高疗效的关键。表明激光对基底细胞癌开辟一个新的治疗手段,值得在临床有更进一步应用研究的必要。     

大乳头水螅基盘再生进程中过氧化物酶的表达

目的观察大乳头水螅(Hydra magnipapillata)基盘再生进程中基盘过氧化物酶的表达情况,探讨水螅基盘过氧化物酶的生理作用。方法通过ABTS细胞化学染色法显示水螅基盘过氧化物酶的表达。结果水螅基盘再生20h后其基盘过氧化物酶开始出现少量表达,其后过氧化物酶表达量逐渐增加;基盘再生52h后该酶表达量趋于稳定。过氧化物酶仅在基盘周边区域外胚层中表达,而在基盘中央区域(反口孔)外胚层中无表达。结论水螅基盘再生进程中过氧化物酶的表达量逐渐增加直接反映了基盘再生时细胞分化过程,基盘表达的过氧化物酶可能在维持基盘结构的稳定上起一定的作用。     

BASAL LEVELS OF METALLOTHIONEIN I AND II EXPRESSION IN MOUSE EMBRYO FIBROBLASTS ENHANCE GROWTH IN LOW FOLATE THROUGH A CELL CYCLE MEDIATED PATHWAY

The impact of basal (non-induced) expression levels of metallothionein I and II on the growth of mouse embryo fibroblasts in standard DMEM/F-12 containing 8.8 microm folic acid, and in DMEM/F12 without hypoxanthine, thymidine or folic acid, containing 15 nm or 15 pm[6S]-folinic acid, was assessed by comparing wild-type MT (+/+) and homozygous null MT (-/-) cell lines. No difference in growth rate was observed between the two in DMEM/F12, although MT (-/-) cells displayed a 6-fold decrease in p27(Kip1), a two fold increase in p53 and a slight increase in p21(Waf1). After 6 days in culture, the growth rate for MT (-/-) cells in 15 nm or 15 pm[6S]-folinic acid was half that of MT (+/+). After an additional 6 days in 15 n m folate, both MT (+/+) and (-/-) cells maintained their respective growth rates, while those in 15 pm had ceased to grow. During the initial 6 days in 15 nm folate, neither cell population displayed an increase in apoptosis or a change in cell cycle distribution, even though MT (-/-) cells sustained an additional 4-fold increase in p21(Waf1)and a 6-fold decrease in cyclin E expression. At day 12, however, the MT (-/-) population, but not MT (+/+), underwent a 7-fold increase in apoptosis coupled with a 3 fold increase in S phase cells. Hence, the basal level of MT I and II constitutively expressed in MT (+/+) cells enhances growth in 15nM [6S]-folinic acid by preventing S phase arrest and apoptosis.     

THE EPIDERMAL PROLIFERATIVE UNIT: THE POSSIBLE ROLE OF THE CENTRAL BASAL CELL

A model is suggested for the organization of the epidermis based on the ordered structure of the differentiating layers, as demonstrated by published work. This ordered structure enables one to look through the epidermis at the basal cell nuclei and to see their arrangement beneath the differentiating column of cells. In dorsal skin from male DBA-2 mice there are 10.6 basal nuclei beneath a column of cells. The central nucleus of the group responds slightly earlier and more effectively than the rest to stimulation, is cycling more slowly than the majority of the basal nuclei and may spend significant periods of time out of cycle. The skin appears to contain a series of fairly independent proliferative units, each of which contain ten or eleven basal nuclei and eight to ten superficial cells of which only the youngest one or two retain their nuclei. At the centre of each group of basal nuclei is a cell that behaves differently from the rest and which is present in the skin in numbers compatible with the number of clonogenic cells. It is suggested that this represents the basic stem cell of the unit.     

打碗花生殖细胞,精细胞及卵细胞中的细胞质类核

已有不少超微结构的资料阐明被子植物双亲和单亲母系质体遗传的细胞学基础。近年应用DAPI荧光染色的方法,可快速地从检测质体DNA存在的状况确定被子植物中具双亲遗传潜能的种。从质体的类核存在与否判断质体遗传方式为母系遗传或双亲遗传与已有的遗传分析结论基本一致,只有少数种类是矛盾的。DAPI荧光技术可以认为是研究细胞质遗传机理的一个重要手段。我们曾证明旋花科牵牛属植物生殖细胞、精细胞中存在细胞质类核,确定其具双亲或单亲父系质体遗传的潜能,并用RFLP技术进一步确定其为质体父系遗传型。本研究证明旋花科的打碗花属生殖细胞、精细胞和卵细胞中细胞质类核存在的状况与牵牛属的相似,提供了打碗花可能在质体遗传上与牵牛属 具相同的遗传方式的资料。     

A meta-analysis of sunburn and basal cell carcinoma risk

Basal cell carcinoma (BCC) is the most common cancer in the United States. Sunburn is a modifiable risk factor for BCC. The objective of this project was to synthesize research on BCC and sunburn to quantify the impact and severity of sunburn at different life stages on BCC risk in the general population. A systematic literature search of four electronic databases was conducted and data were extracted by two independent reviewers using standardized forms. Data from 38 studies were pooled using both dichotomous and dose-response meta-analytic methods. BCC risk increased with ever experiencing a sunburn in childhood (OR=1.43, 95% CI: 1.19, 1.72) and with ever experiencing a sunburn in life (OR= 1.40, 95% CI: 1.02, 1.45). Every five sunburns experienced per decade in childhood increased BCC risk by 1.86 (95% CI: 1.73, 2.00) times. Every five sunburns experienced per decade in adulthood increased BCC risk by 2.12 (95% CI: 1.75, 2.57) times and every five sunburns per decade of life increased BCC risk by 1.91 (95% CI: 1.42, 2.58) times. The data on sunburn exposure and BCC show that an increase in number of sunburns at any age increased the risk of BCC. This may inform future prevention efforts.