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1.
冯炎 《四川动物》2006,25(3):493-498
1980~2000年调查四川二郎山地区有瓣蝇类(Calyptratae)地理垂直分布。共获成蝇7科88属264种,本文优选其中代表性蝇类30种,以分析其地理垂直分布情况。结果发现因各蝇种特有生态习性的不同而各自在不同垂直地带表现不同的虫口数量分布。  相似文献   

2.
The ionic composition of human prostatic fluid varied greatly between individuals, reflecting the secretory activity of the gland and the presence or absence of prostatic inflammatory disease. In normal prostatic fluid the major anion was citrate, while chloride concentrations were lower. Their counterions were mainly sodium and potassium, together with calcium, magnesium and zinc. Prostatic secretions from men with prostatitis comprised mainly sodium and chloride. The electrolytes were closely correlated to each other (except for sodium, which was essentially invariant at about 145 nm). The molar changes per mole of citrate were about 0.52, potassium; -0.53, chloride; 0.17, calcium; 0.14, magnesium; and 0.09, zinc. The pH was also associated with citrate, decreasing from 8.0 to 6.2 as the citrate increased. These various ionic changes can be explained as responses to citrate secretion, without the need to propose specific transport mechanisms for the other ions measured. The marked effect of prostatic inflammation on the composition of prostatic fluid can be seen as being due mainly to decreased secretion rather than active modification.  相似文献   

3.
为了解武功山地区有毒植物资源情况及毒性特点,有效保护与利用武功山有毒植物资源,通过野外实地考察并结合查阅文献资料的方法,对该地区的有毒植物进行统计分析。结果显示,武功山地区共有有毒植物75科179属240种;形成以豆科(Leguminosae)、毛茛科(Ranunculaceae)、菊科(Asteraceae)、百合科(Liliaceae)4科为主的数量优势科(含10种及以上),以紫堇属(Corydalis)为主的数量优势属(含5种及以上)。该区有毒植物的生活习性以草本为主;以海拔400~499 m区域内的植物最多,且主要生长在山坡、林中、灌丛等环境中。区系地理成分复杂多样,科以泛热带分布和世界分布为主,属以北温带分布和泛热带分布为主,而种以中国特有分布和东亚分布最多。毒性以小毒为主,有毒部位以全株有毒为主;有毒化学成分颇为复杂,主要以生物碱为主,毒理类型以神经系统毒为主。  相似文献   

4.
W Fleck  D Strauss  W Koch  H Prauser 《Antibiotiki》1975,20(11):966-972
The conditions of fermentation, isolation and some of the physico-chemical properties of the new anthracycline antibiotics, i. e. viomycin A, BI, BII and their aglycones, produced by a strain of Streptomyces violaceus IMET JA 6844 are described. Violamycin A is mainly a complex of aminoglycosides of epsilon- and dzeta-isorhodomycinone, beta-rhodomycinone and (alpha)2-rhodomycinone. The sugar component is rhodosamine. Violomycin BI is mainly a complex of trisaccharides of the same aglycones mentioned above. The sugar components are rhodosamine, 2-desoxy-L-fucose and rhodinose. Violomycin BII is mainly a rhodosaminyl-2-desoxy-L-fucosyl-derivative of epsilon- and dzeta-isorhodomycinone, beta- and epsilon-rhodomycinone and (alpha)2-rhodomycinone. Violamycin complexes A, BI, BII mainly consist of 6 aglycone components which are similar to the other members of anthracyline antibiotics but can be diferentiated from them by physico-chemical and biological properties. Epsilon- and dzeta-isorhodomycinone, epsilon- and (alpha)2-rhodomycinone and dzeta-rhodomycinone one of the 8 minor components contained in the mixture of the aglycones of the violomycin complex so far has been determined as constituents of an antibiotic.  相似文献   

5.
We assess phylogenetic relationships within the polychaete family Hesionidae from morphological data combined with nucleotide data from 18S rDNA, 28S rDNA, 16S rDNA and COI. Parsimony and Bayesian analyses were performed on two data sets; the first was based on a more restricted set of terminals with both morphological and molecular data (17 ingroup terminals), while the second included additional taxa with morphological data only (25 ingroup terminals). The different sets of terminals yielded fully congruent results, as did the parsimony and the Bayesian analyses. Our results indicate high levels of homoplasy in traditionally used morphological characters in the group, and that Hesioninae, Gyptini and Gyptis are nonmonophyletic. Hesionini (mainly Hesione and Leocrates ), Psamathini (mainly Hesiospina , Micropodarke , Nereimyra , Psamathe and Syllidia ), Ophiodrominae (Gyptini and Ophiodromini) and Ophiodromini (mainly Heteropodarke , Ophiodromus and Podarkeopsis ) are monophyletic and agree with previous classifications, and Hesionini is probably the sister to all other hesionids. The placements of the small hesionids capricornia and Lizardia , the hydrothermal vent taxa Hesiodeira and Hesiolyra , and the newly described Hesiobranchia , remain uncertain.  相似文献   

6.
地形是土地景观格局变化的重要因素.为揭示不同地形梯度下景观格局的时空特征和变化规律,以1995、2005和2015年3期福州市遥感影像和数字高程模型(DEM)数据为基础,运用地形位指数、土地利用分布指数、地学信息图谱分析和景观指数等方法,探讨景观格局的地形梯度效应以及形成原因.结果表明: 研究期间,研究区林地主要位于中低、中高和高等级地形位,农地、水体、建设用地和未利用土地主要集中位于低等级地形位.1995—2015年,福州市林地、农地和未利用土地面积减少,建设用地和水体面积增加.景观类型变化以稳定型为主,主要分布于中低、中高及高等级地形梯度区域;景观格局在地形梯度上变化差异明显,低地形位区域景观类型主要转向建设用地,而在中低及中高地形位区域,主要发生农地与林地的交替转变.研究区景观格局破碎化、景观异质性和景观多样性等属性逐年上升,随着地形梯度升高而降低.  相似文献   

7.
Summary This study is based both on our own results, especially δ13C analyses, and on data in the literature. Of the 225 species of Poaceae reported from Egypt, 105 species show the C3 and 120 the C4 type of photosynthetic CO2 fixation. Winter annual and perennial grasses active in winter are mainly C3 species, while summer annuals and the other perennials are mainly C4 species. The percentage of C3 species decreases with decreasing latitude. This seems to be mainly related to increasing temperatures. The C3 grass species are found preferentially in the Mediterranean, Irano-Turanian, Mediterranean/Irano-Turanian, and Saharo-Arabian chorotypes, while the C4 species are mainly found in the Sudanian, Saharo-Arabian/Sudanian and Tropical chorotypes. In Egypt, the NADP+-ME and NAD+-ME subtypes of C4 photosynthesis are found in about equal numbers of C4 species, while the PCK subtype is relatively rare.  相似文献   

8.
水稻物质生产与氮、磷、钾、硅素积累特点及其相互关系   总被引:1,自引:0,他引:1  
大田条件下研究了30个水稻基因型的干物质与N、P、K、Si积累特性及其相互关系.结果表明,水稻干物质积累总量随N、P、K和Si积累总量的增加呈直线增加,其相关系数早季和晚季均达极显著水平.同时,N、P、K、Si积累的平衡有利于干物质积累,干物质积累量随NBI(养分平衡指数)直线增加,随NDI(养分偏离指数)直线下降.30个水稻品种平均N、P、K、Si积累总量比值早季为3.76:1:4.55:7.10,晚季为2.88:1:4.54:8.09.干物质积累能力以中期最强,前期最弱,而N积累能力却以前期最强,后期最弱.水稻抽穗前积累的干物质主要分配在茎鞘中,当抽穗期茎鞘比率达到最大时,茎鞘重约为叶片重的2倍,而抽穗前积累的N主要分配在叶片中,叶片中N的分配比率全生育期均比干物质分配比率高.成熟期积累的干物质、N和P主要分配在穗部,早、晚季稻的平均分配比率分别为58.01%、66.42%和70.06%,而K主要分配在茎鞘中,早、晚季稻的平均分配比率为62.08%.早季Si在茎中的分配比率(43.11%)最大,而晚季却以穗中的分配比率(46.99%)最大.  相似文献   

9.
Glucoraphasatin: Chemistry, occurrence, and biological properties   总被引:1,自引:0,他引:1  
Glucoraphasatin is an atypical glucosinolate mainly found in Raphanus sativus roots and sprouts. This review focuses on the chemistry, the occurrence, and the biological properties of glucoraphasatin.  相似文献   

10.
The His-Phe-Arg-Trp-Pro-Gly-Pro [ACTH-(6–9)-PGP] peptide was synthesized. Proteolysis of ACTH-(6–9)-PGP and semax (Met-Glu-His-Phe-Pro-Gly-Pro) in the presence of leucine aminopeptidase and carboxypeptidase Y was studied. If the proteolysis of ACTH-(6–9)-PGP is mainly defined by aminopeptidases, the basic metabolite is Trp-Pro-Gly-Pro. Identification of major metabolites of ACTH-(6–9)PGP when incubated with the enzymes in vitro made it possible to evaluate proteolysis pathways of the peptide and prepare necessary amounts of its metabolites for using them as standards. Kinetics of ACTH-(6–9)PGP degradation in the presence of enzyme systems of nasal mucus, blood, and plasma were also explored. It was found that proteolysis of ACTH-(6–9)-PGP in rat blood and plasma occurs mainly under the effect of enzymes whose action is similar to leucine aminopeptidase.  相似文献   

11.
水稻物质生产与氮、磷、钾、硅素积累特点及其相互关系   总被引:34,自引:5,他引:29  
大田条件下研究了30个水稻基因型的干物质与N、P、K、Si积累特性及其相互关系.结果表明,水稻干物质积累总量随N、P、K和Si积累总量的增加呈直线增加,其相关系数早季和晚季均达极显著水平.同时,N、P、K、Si积累的平衡有利于干物质积累,干物质积累量随NBI(养分平衡指数)直线增加,随NDI(养分偏离指数)直线下降.30个水稻品种平均N、P、K、Si积累总量比值早季为3.76:1:4.55:7.10,晚季为2.88:1:4.54:8.09.干物质积累能力以中期最强,前期最弱,而N积累能力却以前期最强,后期最弱.水稻抽穗前积累的干物质主要分配在茎鞘中,当抽穗期茎鞘比率达到最大时,茎鞘重约为叶片重的2倍,而抽穗前积累的N主要分配在叶片中,叶片中N的分配比率全生育期均比干物质分配比率高.成熟期积累的干物质、N和P主要分配在穗部,早、晚季稻的平均分配比率分别为58.01%、66.42%和70.06%,而K主要分配在茎鞘中,早、晚季稻的平均分配比率为62.08%.早季Si在茎中的分配比率(43.11%)最大,而晚季却以穗中的分配比率(46.99%)最大.  相似文献   

12.
The lung lining and its surfactant have been studied in one species from each of the amphibian sub-classes Anura, Urodela, and Apoda. The surfactant was studied by observation of bubbles derived from the lungs, the morphology by electron microscopy. Other details of the apodan are also given.
The surfactant layers of Rana temporaria and Ichthyophis (species unknown) resemble one another, being somewhat less stable than that of mammals. That of Triturus vulgaris is even less stable, and shows qualitative differences from the other two. Nevertheless, it can reduce the surface tension to 2 mN/m.
The epithelial cells of amphibian lungs cannot be divided into two clearly defined types, as can those of mammals. Microvilli are present on the alveolar surface of all these cells. In the lungs of Rana and Ichthyophis the lining cells contain numerous lamellated osmiophilic bodies (which are intracellular depots of surfactant); in the former their appearance is mainly cross-barred, in the latter mainly concentric. Similar bodies exist in the lung epithelial cells of Triturus but are relatively rare.  相似文献   

13.
Seeds of Raphanus sativus L. subjected to accelerated ageing were investigated for reactive oxygen species (ROS) release and for content of vitamin E (tocopherol, TOC, and tocotrienol, TOC-3), fatty acids and phytosterols in seed coats, cotyledons and embryonic axes during germination. In unaged seeds, ROS release occurred mainly in seed coats of non-imbibed seeds and in seedlings (48?h of imbibition). TOC and TOC-3 were mainly represented by the ??-isoform, abundant in embryonic axes. Fatty acids were mainly found in cotyledons. In seed coat and embryonic axis, phytosterols consisted mainly of sitosterols. The effects of ageing were mainly visible in embryonic axes at 48?h of imbibition. Deterioration was associated with a decrease in fresh weight increase percentage, germination percentage, ??-TOC and total fatty acid content. An increase in ROS release from seed coats and in ??-TOC, ??-TOC, ??-TOC-3 content in embryonic axis was also observed. The use of ??-TOC and total fatty acids in embryonic axis as parameters of seed quality evaluation during storage was suggested.  相似文献   

14.
华北东濮凹陷沙河街组藻类化石所记录的地质事件   总被引:1,自引:0,他引:1  
东濮凹陷早第三纪沙河街组产有丰富的藻类化石,淡水藻类与半咸水,咸水藻类相互交替的两个旋回在纵向上分布明显,即:沙四,沙二段为淡水藻类(主要为轮藻)发育期,沙三,沙一段为咸水,半咸水藻类(主要为沟鞭藻)发育期,根据藻类化石的生态分析。认为沙三,沙一段沉积期湖水的咸化事件是由海侵造成的。  相似文献   

15.
Primatologists have classified rhesus macaques of the Taihangshan Mountains area as Macaca mulatta tcheliensis, a subspecies confined to China. The northernmost area of its distribution is in the southern part of the Taihangshan Mountains, which includes a National Nature Reserve established in 1998. To investigate the current status of the subspecies, we surveyed the population and distribution of macaque groups in Jiyuan, Henan, China. In addition, we investigated habitat preferences and the food items foraged by macaques during winter and early spring. The results show that: 1) ca. 2100 macaques currently inhabit the Taihangshan Mountains National Nature Reserve, mainly in Jiyuan; 2) fragmentation of habitats of rhesus macaques have become severe in recent years; and 3) food resources are very poor during the long winter and the early spring. Macaques in the Taihangshan Mountains feed mainly on seeds, twigs, and bark and the eggs of some insects.  相似文献   

16.
Huang  Yue-Hui  Li  Jin-Tao  Zan  Ke  Wang  Jun  Fu  Qiang 《Phytochemistry Reviews》2022,21(4):1081-1184
Phytochemistry Reviews - Plants of genus Eleutherococcus belong to Araliaceae family, which mainly distributed in Asia. Several Eleutherococcus species have been used as ancient medicinal plants...  相似文献   

17.
A new species of calanoid copepod, Stephos marsalensis, isdescribed from central Mediterranean coastal waters. It differsfrom congeners mainly in the structure of the fifth legs inboth sexes.  相似文献   

18.
The feeding of bleak, Alburnus alburnus (L.), was studied in a natural eutrophic lake of northern Greece by an analysis of gut contents. Feeding was more intense during the first half of the day. Monthly analyses showed temperature-dependent feeding intensities, which were high during summer and the beginning of autumn and showed a decline in winter. The low feeding intensity in April coincided with the maximal value of the GSI. Bleak is a zooplankton feeder mainly, consuming Copepoda and Bosmina all the year round. During the hot period the diversity of its food increased. Other Cladocera, mainly Diaphanosoma , but also Moina, Daphnia and other less abundant genera, were found also. Meanwhile, Hydracarina and insect nymphs were found frequently, but in very low quantities. The size of bleak did not play an important role in its food composition. The stenophagic nature of its feeding could be explained in terms of the abundance of zooplankton in the environment. The influence of feeding intensity on the condition factor of the species is discussed.  相似文献   

19.
Rhinocricus Karsch, 1881 has 207 species occurring mainly in the Americas, and more than 60 of them were described from Brazil. The genus was proposed base  相似文献   

20.
The diet of the neotropical otter (Carnivora, Mustelidae) was studied from September 1995 to March 1997, in Volta Velha, an Atlantic Forest reserve in the coastal plain of Santa Catarina State, southern Brazil. Fecal samples were collected monthly along the rivers Saí-Mirim, Braço do Norte and Volta Velha. Additionally, from October 1996 to June 1997, a qualitative and quantitative study of fish species available in the studied rivers was performed. The analysis of 202 collected fecal samples indicated a diet based on fish (mainly Hoplias malabaricus and Geophagus brasiliensis) and crustaceans (mainly Trichodactylus fluviatilis, a river crab), characterizing the neotropical otter as piscivorous-cancrivorous in the study area. The presence of fruits, reptiles, birds and mammals in the diet is occasional and opportunistic. Probably the higher consumption of a certain fish species compared to its availability and the high percentage of occurrence of T. fluviatilis in scats of the neotropical otter reflect their higher catchability.  相似文献   

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