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排序方式: 共有438条查询结果,搜索用时 15 毫秒
31.
对新种丽花兰Cymbidium concinnum Z. J. Liu &; S. C. Chen和新变种龙州兰C. eburneum var. longzhouense Z. J. Liu &; S. C. Chen进行了描述和绘图; 丽花兰与大雪兰C. mastersii Griff. ex Lindl.有亲缘关系, 区别点在于新种叶片先端不分裂, 花序具18-22朵花, 唇瓣中裂片上有一个V型的紫红色斑块; 龙州兰(变种)与独占春(原变种)的主要区别在于唇瓣中裂片上和侧裂片顶部有较密的紫红色斑。对象牙白C. maguanense的分类问题进行了讨论, 并为其指定了新模式; 还为腋花组sect. Eburnea国产种类提供一个检索表。 相似文献
32.
Matthew J. Mason Sarah J. Lucas Erica R. Wise Robin S. Stein Melinda J. Duer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(12):1349-1357
The densities of middle ear ossicles of golden moles (family Chrysochloridae, order Afrosoricida) were measured using the
buoyancy method. The internal structure of the malleus was examined by high-resolution computed tomography, and solid-state
NMR was used to determine relative phosphorus content. The malleus density of the desert golden mole Eremitalpa granti (2.44 g/cm3) was found to be higher than that reported in the literature for any other terrestrial mammal, whereas the ossicles of other
golden mole species are not unusually dense. The increased density in Eremitalpa mallei is apparently related both to a relative paucity of internal vascularization and to a high level of mineralization.
This high density is expected to augment inertial bone conduction, used for the detection of seismic vibrations, while limiting
the skull modifications needed to accommodate the disproportionately large malleus. The mallei of the two subspecies of E. granti, E. g. granti and E. g. namibensis, were found to differ considerably from one another in both size and shape. 相似文献
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34.
目的 探讨高温致神经管畸形(NTDs)作用的分子机制,为防治NTDs的发生提供理论依据.方法 在高温致金黄地鼠NTDs模型的基础上,应用免疫荧光染色技术,观察NTDs发生过程中p-ERK1/2在鼠胚神经上皮细胞中的表达变化.结果 对照组和实验组孕鼠在高温水浴处理后16、24h,p-ERK1/2免疫阳性产物分布于鼠胚神经上皮细胞和周围间充质细胞的胞浆中;水浴后36、60h,p-ERK1/2表达部位出现了由细胞浆向细胞核的转移;高温处理后,p-ERK1/2在实验组各期胚胎神经上皮细胞内的表达均比对照组减弱.结论 ERK1/2参与胚胎神经管的发育过程,其表达降低在高温致神经管畸形的发生中起重要作用. 相似文献
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Callus-derived rhizomes of Cymbidium ensifolium var. misericors produced flowers precociously on a defined basal medium (1/2MS) containing of NAA with thidiazuron (TDZ), N6-(2-isopentenyl) adenine (2iP) or N6-benzyladenine (BA) within 100 d of culturing. Among eight cytokinins tested, TDZ at 3.3–10 µM or 2iP at 10–33 µM combined with 1.5 µM NAA were the most effective combinations for achieving flower induction in vitro. These undersized flowers were physically normal and bloomed for two weeks in vitro. 相似文献
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38.
D. Weinert Dietmar Weinert Peter Fritzsche Rolf Gattermann 《Chronobiology international》2001,18(6):921-932
The golden hamster (Mesocricetus auratus) is one of the most frequently used laboratory animals, particularly in chronobiological studies. One reason is its very robust and predictable rhythms, although the question arises whether this is an inbreeding effect or rather is typical for the species. We compared the daily (circadian) activity rhythms of wild and laboratory golden hamsters. The laboratory hamsters were derived from our own outbred stock (Zoh:GOHA). The wild hamsters included animals captured in Syria and their descendants (F1). Experiments were performed under entrained (light: dark [LD] 14h:10h) and under free-running (constant darkness, DD) conditions. Locomotor activity was recorded using passive infrared detectors. Under entrained conditions, the animals had access to a running wheel for a certain time to induce additional activity. After 3 weeks in constant darkness, a light pulse (15 min, 100 lux) was applied at circadian time 14 (CT14). Both laboratory and wild hamsters showed well-pronounced and very similar activity rhythms. Under entrained conditions, all hamsters manifested about 80% of their total 24h activity during the dark portion of the LD cycle. The robustness of the daily rhythms was also similar. However, interindividual variability was higher in wild hamsters for both measures. All animals used the running wheels almost exclusively during the dark portion of the LD cycle, although the wild hamsters were three times more active. The period length, measured in constant darkness, was significantly shorter in wild (23.93h ± 0.10h) than in laboratory hamsters (24.06 ± 0.07h). The light-induced phase changes were not different (about 1.5h). In summary, these results indicate that the laboratory hamster is not much different from the wild type. (Chronobiology International, 18(6), 921-932, 2001) 相似文献
39.
To investigate which component of the plasma membrane of the hamster egg plays the central role in the sperm–egg fusion, the egg membrane was treated with a variety of proteolytic, carbohydrate-hydrolyzing, lipid-hydrolyzing, and other enzymes. The only enzyme that markedly effected the ability of the egg membrane to fuse with spermatozoa was phospholipase C. The lipid moieties of the egg plasma membrane (and possibly of the sperm membrane) must be of primary importance in sperm–egg fusion at fertilization. 相似文献
40.
《Ostrich》2013,84(3):281-284
Golden Nightjar Caprimulgus eximius is an apparently sedentary sub-Saharan species with a breeding range extending from Senegal and Mauritania to Sudan. Although genetic studies of nightjars and related Caprimulgiformes have been published previously, none has included Golden Nightjar. In this study, mitochondrial and nuclear DNA of a Golden Nightjar found dead in Western Sahara in April 2016 was sequenced and compared with other species in the genus Caprimulgus. It was concluded with strong support that Golden Nightjar is closely related to Egyptian Nightjar C. aegyptius. It is hypothesised that Golden and Egyptian Nightjars may have arisen by splitting of a single ancestral species into migratory and sedentary populations. 相似文献