共查询到20条相似文献,搜索用时 15 毫秒
1.
M A Lodder 《European journal of morphology》1991,29(1):5-30
In this study the structures in the hindleg of the kangaroo which are potentially available for jumping were examined. Specimens of two species, Macropus giganteus and Aepyprymnus rufescens, were examined and are described and compared. The basic pattern of the jump of the two species is similar. This is reflected anatomically by the fact that in both species the extensors of the hip, knee and ankle as a percentage of the total weight of the hindleg are greater than the flexors of the same joints. An additional similarity is that the biceps femoris and adductor magnus have the greatest share in the weight of the hip extensors. Furthermore the estimated total force of the hip, knee and ankle extensors and total moment of the hip and ankle extensors are always greater than the flexors of the same joints. However, the percentage of the hip and knee extensors, the absolute forces and moments of both the extensors and flexors and the range of movement especially of the hip and knee are always greater in M. giganteus than in A. rufescens. As well as these differences, the long tibia and the position of the knee in view of the hip may be important factors for the longer jump achieved by M. giganteus. In comparison A. rufescens has a anatomical construction which seems to be a compromise between walking and jumping. 相似文献
2.
马铃薯'转心乌'块茎色素的组成和含量 总被引:2,自引:0,他引:2
马铃薯转心乌块茎的内、外韧皮部和髓为淡黄色,周皮和木质部为紫色;木质部的紫色形成一个不规则的环",并向内韧皮部蔓延.系列特征颜色反应和紫外可见光谱分析表明:‘转心乌’块茎紫色素属于黄酮类化合物,可能含有酚性邻位二羟基,并被肉桂酸酰化,不含类胡萝卜素、查耳酮、噢哢、异黄酮、儿茶素;花色苷和/或其苷元花色素奠定了‘转心乌’块茎着色的基础,其它的非红色的黄酮类化合物发挥共色素的作用.块茎的皮"紫色最浓","环"其次,"肉"最淡,这与"皮"、"环"和"肉"的色价、花色苷含量和总黄酮类化合物含量的变化趋势呈正相关. 相似文献
3.
将小叶杨分别与其他11个树种枯落叶粉碎混合后进行室内分解培养,分析不同树种枯落叶混合分解对土壤性质的影响及其相互作用.结果表明:12个树种枯落叶单独混土分解均明显提高了土壤脲酶、脱氢酶、磷酸酶活性和有机质、碱解N含量,但对土壤速效P含量和土壤阳离子交换量(CEC)的影响差异较大,其中柠条和紫穗槐枯落叶改善土壤性质的效果明显.小叶杨分别与油松、侧柏、刺槐、白榆枯落叶混合分解,对土壤微生物数量的影响存在相互促进作用;小叶杨分别与侧柏、柠条枯落叶混合分解对土壤有机质、速效P、速效K含量和CEC的影响存在相互促进作用,但对土壤大部分酶活性的影响却存在相互抑制作用;小叶杨与落叶松枯落叶混合分解对土壤多数酶活性和养分含量的影响存在相互促进作用,而与樟子松枯落叶混合分解时则有抑制作用.总体上,小叶杨分别与白榆、油松、落叶松和刺槐枯落叶混合分解可促进土壤性质的改善,而与侧柏、柠条、樟子松、沙棘和紫穗槐枯落叶混合分解时则相互抑制. 相似文献
4.
BACKGROUND AND AIMS: Bamboos are among the most important plants in the world. The anatomical structure and mechanical properties of the culm internode are well documented. Fewer details are available of the culm node. The aim of this study was a topochemical investigation on lignification and cell wall thickening in developing and maturing bamboo nodes. The deposition sequence and distribution of lignin structural units and cell wall thickening in different anatomical regions of the node of Phyllostachys viridiglaucescens and Phyllostachys nigra are discussed. METHODS: Cell wall thickening and lignification are investigated in the outer part of the nodal region and in the diaphragm of developing and maturing P. nigra culms and in maturing culms of P. viridiglaucescens of different age classes. The lignification during ageing was studied topochemically by means of cellular UV microspectrophotometry. A combination of light microscopy and image analysis techniques were used to measure cell wall thickness. KEY RESULTS: The fibre and parenchyma cell wall thickness does not significantly increase during ageing. In the diaphragm, the cell walls are thinner and the cell diameter is larger than in the outer part of the node. In shoots, the lignin content in the epidermis, hypodermis and in both fibre and parenchyma cells of the diaphragm is relatively low compared with older culms. The fibre and parenchyma cells of the diaphragm have higher values of p-coumaric and ferulic acids than fibre and parenchyma cells of the outer part of the node. CONCLUSIONS: It was hypothesized that the combination of more hydroxycinnamic acids and of thinner cell walls in combination with higher cell diameters (lower density and lower stiffness) in the diaphragm than in the outer part of the node may play an important role in the biomechanical function of the node by acting as a spring-like joint to support the culm by bending forces. 相似文献
5.
M Ia Orgel' L V Parkhomenko M A Elshina 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1975,(8):81-85
Morita and Perkins' method was applied to the study of the stage of ingestion and destruction of an antigen (sheep erythrocytes) in the macrophages of peritoneal exudate of rabbits and rats and in the microphages of rabbit pleural exudate. Ingestion and intracellular destruction of the antigen were accompanied by intensified respiration and glycolysis of phagocytes. Respiration of the three types of phagocytes at two stages of phagocytosis and also the digestive capacity of microphages proved to be sensitive to cyanide and colchicine. The latter failed to influence the ingestion of the antigen by the three types of phagocytes and its digestion by macrophages. The differences in the metabolism routes of macro- and microphages in intracellular destruction of the antigen was postulated. An intensification of the phagocytic activity after the immunization was characteristic of rabbit and rat macrophages. 相似文献
6.
本文研究了广西龙胜县里骆林区、宜山县庆远林区、岑溪县七坪林区和田林县老山林区四种不同生态地理区域杉木人工林土壤微生物及其生化活性。研究结果表明:1.土壤微生物的总数及各类群数量均以龙胜县里骆林区和田林县老山林区杉木人工林土壤最高,岑溪县七坪林区次之,宜山县庆远林区最低。2.土壤生化活性包括土壤氮的转化强度,土壤碳的氧化代谢能力和土壤酶活性,也均以龙胜县里骆林区和田林县老山林区杉木人工林土壤最强,岑溪县七坪林区次之,宜山县庆远林区最弱。3.四种不同生态地理区域杉木人工林生长状况与土壤微生物的数量分布和生化活性表现相似规律,龙胜县里骆林区和田林县老山林区杉木人工林林木生长最好,岑溪县七坪林区次之,宜山县庆远林区最差。 相似文献
7.
The suitability and limitations of essential methods and reference substrates used for characterisation of activity of amylolytic enzymes is investigated. Saccharogenic, chromogenic and chromatographic methods are included. The results are discussed in relation to the measurement of reaction rates, determination of action mode and product specificity and the impact on identification and nomenclature of malto-oligosaccharide-forming amylases. An accurate determination of reaction rates using the saccharogenic methods strongly depends on the degree of polymerisation (DP) of the standards used and the hydrolysis products formed by the amylase. Particularly the use of glucose as standard can lead to overestimates due to the differences in the reducing potential of glucose and malto-oligosaccharides. The reliability of the chromogenic methods for determination of action mode depends on the DP of the substrate and the specificity of the amylase. For a characterisation of the starch hydrolysis products and the variation in the DP during hydrolysis, high performance anion-exchange chromatography with pulsed amperometric detection provided a fast and reliable method. A literature survey revealed varying and inconsistent use of nomenclature of malto-oligosaccharide forming amylases. Therefore a systematic approach identifying three main classes of activity is suggested using not only the mode of action and the DP of the major product but also the stage of hydrolysis at which this product is formed. 相似文献
8.
G. B. Khomutov 《Biophysics》2011,56(5):843-857
Biophysicochemical approaches to the solution of nanotechnology problems associated with the design of functional biomimetic
nanosystems, hybrid and composite nanobiomaterials and study of their structure-function relationships. The results of studies
concerned with physicochemical mechanisms of the formation of organized biomimetic nanostructures and bioinorganic nanomaterials
in systems involving a bulky liquid phase and the interface (gas-liquid, solid-liquid, liquid-liquid)during the synthesis
and structure formation with the participation of the components of colloid systems, inorganic nanoparticles of various composition
and clusters of metals, surfactants, polyelectrolytes and their complexes are discussed. In the development of the methods
for the formation of composite bioinorganic nanosystems containing inorganic nanocomponents, two major approaches were used:
adsorption and incorporation into the biomolecular matrix or colloid system of presynthesized inorganic nanoparticles, as
well as the synthesis of the inorganic nanophase immediately in the biomolecular system. The methods of obtaining biomaterials
and nanosystems are based on the principles of biomimetics, biomineralization, self-assembly and self-organization, combination
and integration of a number of synthetic and physicochemical methods (physical and chemical adsorption, Langmuir technique,
the formation of polycomplexes, chemical linking, competitive interactions, and substitution of ligands in supramolecular
and coordination complexes) and nanocomponents of different nature. In particular, a novel approach to the preparation of
highly organized nanofilm materials was developed, which is based on the effect of self-assembly and self-organization of
colloid nanoparticles during the formation of their complexes with polyfunctional biogenic ligands in the volume of the liquid
phase in the absence of any surfaces and interfaces. The physical and chemical factors responsible for the formation of structurally
ordered biomolecular and composite nanosystems including nano-sized components of different nature and the possibilities to
control the composition, structure, and properties of resulting nanomaterials and nanosystems are discussed. The experimental
methods and approaches developed may be useful in studies of structure-property relationships and basic mechanisms of structural
organization and transformation at the nanoscales level in biological, artificial, and hybrid nanosystems. The problems of
practical application of the synthetic methods and the corresponding nanomaterials are discussed. 相似文献
9.
洞庭湖景观格局变化及其对水文调蓄功能的影响 总被引:1,自引:0,他引:1
景观格局影响并决定着湿地水文调蓄过程和功能。基于洞庭湖区1980、1990、2000和2005年的景观格局数据和相应4年的水文实测数据,利用灰色关联分析,探讨了洞庭湖景观格局变化对水文调蓄功能的影响及其作用机制。结果表明,洞庭湖区景观格局指数与调蓄功能存在不同程度的相关性,其中调蓄量与最大斑块指数和聚合度指数关联度最大,分别为0.77和0.75,说明景观中的优势斑块大小以及同质斑块间的连通性有利于湖区调蓄能力的增加。泥沙沉积率与斑块数、形状指数、多样性指数和均匀度指数关联度也较大,变化于0.7—0.78之间,说明景观的破碎化程度,多样性,形状复杂度的增大会加大湖区泥沙沉积率。分流比、分沙比与景观格局指数的关联度均较小。景观类型指数与调蓄量的关联度分析表明,水田、林地和水体的最大斑块指数和聚合度指数与调蓄量关联度均较高,说明水田、林地和水体最大斑块面积和聚合度的增大有效增大了湖区调蓄能力。 相似文献
10.
The contents of ammonia, nitrites, nitrates, phosphates, and silicates were measured in pore waters of subtidal sands in Vostok Bay, the Sea of Japan. The exchange of nutrients between sand and pore waters was studied in the laboratory using a running-water system while percolating the ground with seawater. The composition of pore waters depended on the method and length of time spent sampling, and also on the distance from the ground surface. Statistical analysis did not reveal stable profiles of nutrient concentrations in sand. The velocities of the release and consumption of nutrients in the experiments were rather low and depended on temperature, length of time spent sampling, duration of measurements, and distance from the sand surface. Release and consumption were connected with absorption and desorption, and were not due solely to the biological process of mineralization of organic matter. Analysis of the data obtained is complicated by the canalization of the water flow in the sand and by the consolidation of the sediment during the measurements. The comparison of pore and near-bottom waters makes it possible to hypothesize that the mineralization of organic matter and the release of nutrients into the pore waters occur throughout the whole column of sediment. The mixing of the seawater and groundwater occurs as a result of advection processes, the most important of which is wave percolation. 相似文献
11.
The paper deals with the visualizing study of the ankle joint and foot by MRI and with the problems in the interpretation of magnetic resonance images in health. For this, 50 healthy volunteers without diseases and lesions of the ankle joint and foot were examined. The study was performed by using flexible superficial coils and T1-, T2-, and proton-weighed pulse-sequences in the orthogonal projections. The articular surfaces and cavity of the ankle joint were evaluated. The specific features of visualization of the muscles and tendons of this area and the pattern of fluid under their membranes were explored. The typical location of the "magic corner" phenomenon was revealed. The individual specific features of identification of the ligaments of the ankle joint and foot and plantar aponeurosis were defined. The features of visualization of bones simulating abnormalities were studied. A category of normalcy in the MRI of the ankle joint and foot was formulated. 相似文献
12.
Summary The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron density of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals. 相似文献
13.
【目的】探究和比较超积累和非超积累生态型东南景天茎、叶微生物群落结构的异同。【方法】采用高通量测序技术研究野外两种生态型东南景天茎和叶片的内生细菌群落结构。【结果】4个样品总共得到366 783条有效序列和39 948个OTU(97%相似度)。从Shannon指数得知:两种生态型东南景天叶片内生菌的多样性均高于茎;超积累生态型东南景天叶片内生菌的多样性高于非超积累生态型,但非超积累生态型东南景天茎组织中内生菌多样性高于超积累生态型东南景天。超积累生态型东南景天的叶片和茎中的内生菌分别包括26和21个门,123和117个科;非超积累生态型东南景天叶片和茎中的内生菌分别包括43和22个门,175和83个科,4个样品的优势菌群均为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)和蓝藻细菌门(Cyanobacteria)。在属分类水平上,超累积生态型东南景天叶片和茎第一优势菌属分别为Synechococcus和Plesiomonas;非超积累生态型东南景天叶片和茎组织第一优势菌群分别为Pseudomonas和Dechloromonas。【结论】两种生态型东南景天的叶片和茎中均具有丰富的内生细菌,但超积累生态型东南景天叶片内生菌多样性最大,且存在一些独有的功能菌群。 相似文献
14.
国家大型煤电基地生态环境监测技术体系研究——以内蒙古锡林郭勒盟煤电基地为例 总被引:2,自引:0,他引:2
随着我国煤电基地建设进程的不断加快,煤电基地建设与开发活动引起的环境问题也日趋严重。了解生态环境质量现状,评估其对生态系统与人民健康水平的影响,制定合理的保护、治理、恢复策略是煤电基地环境保护工作的重中之重,而生态环境监测是解决上述问题的基础。然而,现有的监测技术体系普遍存在自动化水平较低、成本较高、时空覆盖面较低等问题。鉴于物联网技术在提高信息采集效率和改善信息获取方式方面的作用日益显著,所以将物联网技术应用于煤电基地生态环境监测,从感知层、传输层、支撑层、应用层、用户层的角度明确生态环境监测技术体系,为解决上述问题提供有效途径。 相似文献
15.
The effect of arm movements and movements of individual arm joints on the electrophysiological and kinematic characteristics of voluntary and vibration-triggered stepping-like leg movements was studied under the conditions of horizontal support of the upper and lower limbs. The horizontal support of arms provided a significant increase in the rate of activation of locomotor automatism by noninvasive impact on tonic sensory inputs. The addition of active arm movements during involuntary stepping-like leg movements led to an increase in the EMG activity of hip muscles and was accompanied by an increase in the amplitude of hip and shin movements. The movement of the shoulder joints led to an increase in the activity of hip muscles and was accompanied by an increase in the amplitude of hip and shin movements. Passive arm movements had the same effect on induced leg movements. The movement of the shoulder joints led to an increase in the activity of hip muscles and an increase in the amplitude of movements of knee and hip joints. At the same time, the movement of forearms and wrists had a similar facilitating effect on the physiological and kinematic characteristics of rhythmic stepping-like movements, but influenced the distal segments of legs to a greater extent. Under the conditions of subthreshold vibration of leg muscles, voluntary arm movements led to activation of involuntary rhythmic stepping movements. During voluntary leg movements, the addition of arm movements had a significantly smaller impact on the parameters of rhythmic stepping than during involuntary leg movements. Thus, the simultaneous movements of the upper and lower limbs are an effective method of activation of neural networks connecting the rhythm generators of arms and legs. Under the conditions of arm and leg unloading, the interactions between the cervical and lumbosacral segments of the spinal cord seem to play the major role in the impact of arm movements on the patterns of leg movements. The described methods of activation of interlimb interactions can be used in the rehabilitation of post-stroke patients and patients with spinal cord injuries, Parkinson’s disease, and other neurological diseases. 相似文献
16.
Moço TC O'Dwyer LH Vilela FC Barrella TH da Silva RJ 《Memórias do Instituto Oswaldo Cruz》2002,97(8):1169-1176
Hepatozoon species are the most abundant hemoparasites of snakes. Its identification has been based mainly on the morphologic characterization of the gamonts in the peripheral blood of the vertebrate host and also of the cysts found in the internal organs of the vertebrate and invertebrate hosts. Using a computerized image analysis system, we studied five species of Hepatozoon from recently captured snakes in Botucatu, State of S o Paulo, Brazil, to evaluate the importance of the morphology and morphometry of the gamonts for the characterization of Hepatozoon species and to analyze the morphologic changes induced in the erythrocytes by the parasite. The studied species were H. terzii of Boa constrictor amarali, Hepatozoon sp. of Crotalus durissusterrificus, H. philodryasi of Philodryas patagoniensis, and H. migonei and H. cyclagrasi of Hydrodynastes gigas. We observed three different groups, one of them including the species H. terzii, H. philodryasi and Hepatozoon sp. of C. durissus terrificus; and the other two consisting of H. migonei and H. cyclagrasi. Degree of alterations in the erythrocytes was variable and it may be useful for characterization of Hepatozoon species. 相似文献
17.
18.
The ultrastructural study of chromatin condensation simultaneously with the evolution of the perinuclear organelles was conducted in the spermatids and epididymal and ejaculated spermatozoa of man with the aid of the “en bloc” alcoholic PTA staining and the EDTA regressive method. The round nuclei of young spermatids (steps 1, 2) were characterized by the persistence of nucleoli that were PTA positive, and the presence of a subacrosomal layer of well-stained peripheral chromatin. In the beginning of the phase of nuclear elongation (step 3), the central chromatin also became dense, like the peripheral chromatin, while the nuclear ring and the associated manchette and the two anlages of the postacrosomal dense lamina and the posterior ring appeared. During steps 4 and 5, the sliding of the nuclear ring and the manchette, the growth of the postacrosomal dense lamina, and the progression of the posterior ring towards the base of the nucleus were seen along with structural and cytochemical modifications of the chromatin. In the flattened nuclei of step 4 spermatids, coinciding with the loss of the nucleolar components, the chromatin achieved maximum compactness in the entire nucleus and was PTA positive. In the spermatids of step 5, the disappearance of peripheral dense chromatin and the specific staining of the chromatin granules marked the beginning of the second stage of transformation of the basic nucleo-proteins. The condensed nuclei of the mature spermatids were partially stained by PTA in step 6 and totally unstained in step 7. The PTA staining revealed the persistence of PTA-positive chromatin areas in the nuclei of certain spermatids otherwise mature. The morphological aspect of the chromatin then remained the same in the nuclei of epididymal and ejaculated spermatozoa. These observations suggest that in man, as in other mammals studied, new proteins accumulate in the elongating nuclei of spermatids and are replaced at the phase of maturation by sperm-specific nucleoproteins. The defects in condensation of the chromatin that occur during spermiogenesis could be related to the modalities of accumulation of intermediate nucleoproteins. 相似文献
19.
中国北方农牧交错带优化生态-生产范式 总被引:6,自引:0,他引:6
中国北方农牧交错带具有生态、生产双重功能,在国民经济发展中具有重要战略地位。构建优化生态生产范式是对其进行科学管理的一种有效方式。优化生态-生产范式是应用生态经济学原理与系统科学方法,以生态恢复与重建为目标,以多用途资源利用和景观生态设计为核心,以生物-自然和社会-经济综合分析为基础,结合现代科学成果和传统农牧业技术的精华而建立起来的结构优化、功能持续、经济可行的农林牧复合经营系统的范例。文章对优化生态生产范式的配置以及配套技术的研究现状进行了综述,提出在构建优化生态生产范式的过程中应当遵守规模的发展与土地承载能力相适应的原则、限制因子原则、景观异质性与尺度的原则以及生态、经济和社会效益统一的原则。针对目前范式研究中着重经济效益、研究尺度单一、缺乏学科间的综合和集成、效益评价体系不完善等一些问题,指出了今后范式研究的趋势,认为今后的研究应重视基础理论和应用技术的研究、对现有范式进行调整和优化、建立统一的评价体系、量化范式适宜程度和优化程度。在基础研究方面应主要集中在主要的农业生态系统对不同人为干扰响应的形式和实质,研究确定一系列重要的生态经济阈值;应用技术方面应注重于调整产业结构,积极发展高科技产业,提高产投比。对范式实施后的各项生态经济指标进行动态监测,从而对范式进行适时调整与优化。对不同范式取得的效益进行横向的、定量的研究,选择出最优的范式。同时,学科间的融入将成为范式研究中的又一特点。 相似文献
20.
The insulin-like growth factors and their binding proteins 总被引:5,自引:0,他引:5
1. This review provides a brief overview of the structure of the insulin-like growth factors (IGFs or somatomedins), their mRNA and genes; the regulation and sites of production of these peptides; their binding and actions in target tissues; and the structure and biological role of their binding proteins. 2. Molecular cloning techniques have allowed the prediction of precursor forms of IGF-I and IGF-II, have provided tools to study the regulation of the synthesis and translation of IGF mRNAs, and have recently yielded the primary sequence of the IGF-I receptor, supplementing other rapidly-accumulating structural data. 3. Several of the IGF binding proteins have also been purified, and initial structural studies performed. 4. The increased knowledge of the structures of the IGFs, their receptors and binding proteins should now permit rapid progress in understanding the physiology and functions of these proteins. 相似文献