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81.
苦丁茶为中国南部及西南部的民间传统药用植物,经两千多年的应用和医学临床试验证明,苦丁茶具有清热解毒、抑菌消炎、抗衰老、降血脂、改善血液粘稠度和微循环、清除人体自由基及增强人体免疫能力等功效,被誉为保健茶、美容茶、降压茶和益寿茶[1,2]。苦丁茶来源较复杂,共有5科1  相似文献   
82.
We report the genomic organization and deduced protein sequence of a cephalochordate member of the Otx homeobox gene family (AmphiOtx) and show its probable single-copy state in the genome. We also present molecular phylogenetic analysis indicating that there was single ancestral Otx gene in the first chordates which was duplicated in the vertebrate lineage after it had split from the lineage leading to the cephalochordates. Duplication of a C-terminal protein domain has occurred specifically in the vertebrate lineage, strengthening the case for a single Otx gene in an ancestral chordate whose gene structure has been retained in an extant cephalochordate. Comparative analysis of protein sequences and published gene expression patterns suggest that the ancestral chordate Otx gene had roles in patterning the anterior mesendoderm and central nervous system. These roles were elaborated following Otx gene duplication in vertebrates, accompanied by regulatory and structural divergence, particularly of Otx1 descendant genes.   相似文献   
83.
黄土高原不同植被覆盖对流域水文的影响   总被引:7,自引:0,他引:7  
张建军  纳磊  董煌标  王鹏 《生态学报》2008,28(8):3597-3605
以山西省吉县蔡家川流域为对象,研究了植被覆盖类型对流域水文的影响.结果表明:不同植被覆盖的流域年径流系数分别为:林地流域1.6%~2.3%,以农、牧为主的流域3.1%~3.9%;各流域基流系数差异显著,人工林流域为零,次生林为主的流域1.0%~1.5%,以农、牧为主的流域2.5%~2.8%;在雨季人工林流域的径流总量是次生林流域的3.37倍、农地流域的1.9倍,而农地流域的基流量是次生林流域的2.2倍;短历时高强度降雨条件下,人工林流域、次生林流域地表径流量分别是农地流域的10.8倍和2.2倍;在历时较长的暴雨条件下,人工林流域单位面积上的洪峰流量是农地流域的3.4倍,次生林流域的6.9倍;在长历时、大雨量条件下,农地流域的径流量是次生林流域的1.8倍.水平梯田的水源涵养功能与次生林植被相当,次生林植被的水源涵养功能远好于人工植被,在水资源短缺的黄土高原应提倡植被的自然恢复.  相似文献   
84.
双斑蟋若虫后足的再生观察   总被引:1,自引:0,他引:1  
李华  张晓欢  那杰 《昆虫知识》2007,44(3):419-422
研究蟋蟀若虫是否具有再生的能力,在实验室内对直翅目蟋蟀科的双斑蟋Gryllus bimaculata de Geer若虫后足的再生情况进行初步观察。结果表明:双斑蟋若虫的后足确实具有再生的能力,且再生足的伸长生长与正常足一样,均出现于虫体蜕皮时。再生的过程主要分为3个阶段:突起期、“肢芽”期、短小足期。实验结果还表明:再生能力与断肢发生的时间及断肢部位有关;断肢部位离肢体越远,再生能力越强;断肢发生的时间越早,再生能力越强。  相似文献   
85.
The object of the research is to classify the nuclear proteins of the cellular nucleus of some types of human skin tumours (melanotic and amelanotic melanomas, squamous epitheliomas). Nuclear proteins were extracted from the nuclei with a saline buffer. Nuclear proteins were extracted from a melanoma step by step. After prolonged centrifugation to sediment the DNA and the large ribonucleoprotein complexes, the nuclear proteins were chromatographed on columns of Biorex 70+ to remove proteins were chromatographed on columns of Biorex 70+ to remove the histones. Nuclear proteins from a squamous epithelioma were injected into a rabbit to induce specific antibodies.  相似文献   
86.
In Vietnam a green strain of tobacco mosaic virus was isolated having TIP 89°C (10 min) and causing systemic necrosis in tobacoo ‘Xanthi-nc’ and sometimes also inDatura stramonium. In symptomless tomato plants an elongated virus belonging apparently to the Carlavirus group (NL 630 nm) was found. In papaya trees showing severe symptoms of mosaic and/or ringspot elongated virus particles (NL 730 nm) were observed; this virus being apparently a member of the Potyvirus group, resembled as far as its symptoms in papaya are concerned, the papaya ringspot or the distortion ringspot. In Cambodia some young rubber trees showed malformed leaves (esp. edges and veins) with yellow discolorations along the veins. Such leaves contained elongated virus-like particles (rigid or slightly flexible) of various length (60 to 880 nm), so that their normal length (NL) could not be established precisely. Particles 120 to 150 nm long occurred very frequently.  相似文献   
87.
Combination chemotherapy by means of two or more drugs is prone to suppressing or discouraging the inception of multidrug resistance, exploiting the fact that diverse drugs act in different points of the cellular cycle of amplifying tumor cells. For example, the combination of gemcitabine (GMC) with quercetin (QCT) showed a synergistic effect in inhibiting the migration of pancreatic cancer cells. Consequently, herein GMC and QCT have been loaded within biodegradable nanoparticles (NPs) based on poly(lactic-co-glycolic acid), externally decorated with hyaluronic acid (HA; viz., PPHA NPs), which plays a major role in drug targeting to tumors due to its ability to specifically interact with CD44 receptor, that is overexpressed in many tumors. The produced HA-decorated NPs loaded with GMC and QCT showed an improved cytotoxicity and cellular uptake toward two cell lines of pancreatic ductal adenocarcinoma, namely Mia-PaCa-2 and PANC-1, compared with both the bare drugs and the drugs loaded in NPs which do not expose HA on the surface. HA-decorated NPs were also able to improve the anti-inflammatory properties of QCT, therefore leading to a decrease of interleukin cellular levels in both cell lines, preliminarily stimulated with lipopolysaccharides. This result is of special interest also considering the crucial role of interleukins in progression, metastatic processes, and drug resistance of human pancreas cancer cells.  相似文献   
88.
In nocturnal treefrogs, mate choice implies the use of acoustic and visual signals. Multimodality is suspected to have evolved for either information redundancy or information complementariness. It is essential to explore multimodality in a natural context to understand the selection pressures operating on the signals. In the present study, we investigated calling and coloration in relation to male biometry and condition in four populations of European treefrog (Hyla arborea) varying in size and genetic isolation. We compared the signal intensity between core and satellite populations to estimate the impact of genetic diversity on male secondary sexual traits. The results obtained show important regional variations in both traits, likely as a result of local adaptations. Call and coloration are weakly correlated within an individual, implying that these traits likely convey different information about the signaller's identity or quality, thus supporting the hypothesis of complementariness of multiple messages. By contrast to the experimental evidence, we find that call and coloration are not related to male condition (as estimated by the residual of mass over size), suggesting that the condition‐dependence of these traits may be mediated by complex mechanisms not accurately reflected by the chosen estimator. Finally, male call and colour phenotypes present no robust pattern of variation with isolation status, probably because of variation in local selective pressures and in history of population dynamics. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 633–647.  相似文献   
89.
90.
东南沿海部队皮肤浅部真菌病的调查研究   总被引:6,自引:2,他引:6  
目的了解东南沿海部队官兵近年真菌菌种构成情况及调查浅部真菌病非高发季节的患病率。方法于11月对浙江地区和福建地区某部队官兵共324人进行浅部真菌病患病情况调查,通过临床检查确定皮肤病种类和感染人(次),对于临床诊断为浅部真菌病的官兵进行真菌镜检证实后明确诊断,并留菌种进行真菌培养。结果真菌感染性疾病患病率为55.2%(324人中179人发病),其中手足癣158人次(48.8%),体股癣35人次(10.8%),花斑癣24人次(7.4%),马拉色菌毛囊炎18人次(5.6%),甲癣5人次(1.5%)。真菌镜检阳性率为76.36%,首位致病菌为红色毛癣菌71株,占84.5%。结论部队尤其是亚热带地区部队,浅部真菌病的患病率较高,不同驻地官兵患皮肤浅部真菌病有差异,而服役年限及兵源与患皮肤浅部真菌病之间无显著差异。  相似文献   
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