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1.
2.
The systematic position ofthe Ebenaceae, Sapotaceae, Styracaceae, Ochnaceae, Stachyuraceae, Dipterocarpaceae, Clusiaceae and Hypericaceae has been investigated using serological comparisons of sets of antigenic determinants. The results show that the Sytracaceae and Sapotaceae are undoubtedly more closely associated with the Actinidiaeceae and Theaceae, respectively, than with each other. We found no corresponding determinants betnween antigen systems from the Ebenaceae and systems from any other family whose relations to this family have been proposed. As discovered previously, investigations of antigen systems from the Ochnaceae, Dipterocarpaceae, Stachyuraceae, Clusiaceae and Hypericaceae are against the idea of a natural order “Theales” in which these families, or at least some of them, are combined with the Theaceae and Actinidiaceae. This paper completes our previous investigations which largely support a superorder Ericanae sensu Ehrendorfer and Takhtajan. We propose to include the Actinidiaceae and Theaceae in this superorder, assigning them a central position laong with the Sapotaceae and Sytracaeae on one side and the Primulales and Ericales on the other. Another most interesting finding is that there are corresponding determinants between antigen systems from the members of the Ericanae and representatives of the Polemoniaceae and Loasaceae.  相似文献   

3.
A light optic and electron microscopic investigation on distribution of fibers from the thalamic posterolateral nucleus has been performed in the cat cerebral cortex. The fibers studied are revealed in the fields 7, 19 and 18. In the field 7 they are most numerous, comparatively seldom they are found in the field 19 and still more seldom--in the field 18. In the fields 7 and 19 identical peculiarities on distribution and termination of the fibers are noted: they spread across the whole cortex and end in all the layers with a predominant concentration in the layers III and IV. Most of the fibers make contacts on small dendritic branches and spines. In the field 18 the fibers are mainly limited by the medial layers and terminate predominantly on small, middle-sized dendritic branches, and comparatively rare--on the spines.  相似文献   

4.
Saccone S  Federico C  Bernardi G 《Gene》2002,300(1-2):169-178
At a resolution of 850 bands, human chromosomes comprise two subsets of bands, the GC-richest H3+ and the GC-poorest L1+ bands, accounting for about 17 and 26%, respectively, of all bands. The former are a subset of the R bands and the latter are a subset of the G bands. These bands showed the highest and the lowest gene densities, respectively, as well as a number of other distinct features. Here we report that human and chicken interphase nuclei are characterized by the following features. (1) The gene-richest/GC-richest chromosomal regions are predominantly distributed in internal locations, whereas the gene-poorest/GC-poorest DNA regions are close to the nuclear envelope. (2) The interphase chromosomes seem to be characterized by a polar arrangement, because the gene-richest/GC-richest bands and the gene-poorest/GC-poorest bands are predominantly located in the distal and proximal regions, respectively, of chromosomes, and because interphase chromosomes are extremely long. While this polar arrangement is evident in the larger chromosomes, it is not displayed by the chicken microchromosomes and by some small human chromosomes, namely by chromosomes that are almost only composed by GC-rich or by GC-poor DNA. (3) The gene-richest chromosomal regions display a much more spread-out conformation compared to the gene-poorest regions in human nuclei. This finding has interesting implications for the formation of GC-rich isochores of warm-blooded vertebrates.  相似文献   

5.
Summary In the mouse, the rostral zone of the pars intermedia is almost exclusively composed of typical corticotrophic cells. They are located around and even within the neural stalk, at the level of transition between stalk and neural lobe. In the rat, the corticotrophic cells of the rostral zone are found in scattered islets among the MSH producing cells, and also in the neural lobe. In both the rat and mouse, these cells are in direct contact with various types of nerve terminals. Synaptoid contacts with aminergic and neurosecretory nerve fibers are observed. Furthermore they are also closely related to the hypophysial portal vessels. Following adrenalectomy, the cells located in the neurohypophysis always react more intensely than tose in the rostral zone. The functional significance of these corticotrophic cells which are subject to both humoral and neural regulation remains as yet hypothetical. Their participation in neurogenic stress response seems probable.  相似文献   

6.
Dean DA 《DNA and cell biology》2003,22(12):797-806
Electroporation has proven to be a highly effective technique for the in vivo delivery of genes to a number of solid tissues. In most of the reported methods, DNA is injected into the target tissue and electrodes are placed directly on or in the tissue for application of the electric field. While this works well for solid tissues, there are many tissues and organs that are not amenable to such an approach. In this review I will focus on the development of electroporation protocols for two such tissues: the vasculature and the lung. Several methods for in vivo electroporation of the vasculature have been developed in recent years that deliver DNA to vessel segments from either the inside or outside of the vessel. The advantages and disadvantages of each are discussed, as are the applications for which they have been used. In more recent work, our laboratory has developed a novel method to deliver genes to the rodent lung that results in high level, uniform, gene expression throughout all cell types of the lung. Most importantly, this technique is safe, and causes no inflammatory response or alterations in normal physiology of the organs. Taken together, these studies demonstrate the utility of electroporation for gene transfer to non injectible tissues.  相似文献   

7.
The human genome, and hence the human brain at birth, may not have changed greatly over the past 60000 years. Yet many of the major behavioural changes that we associate with most human societies are very much more recent, some appearing with the sedentary revolution of some 10000 years ago. Among these are activities implying the emergence of powerful concepts of value and of the sacred. What then are the neuronal mechanisms that may underlie these consistent, significant (and emergent) patterns of behaviour?  相似文献   

8.
Data on the distribution of flavonoids in the angiosperms are summarized and patterns of occurence are shown to be related to plant evolution. Different flavonoid types are regarded as primitive or advanced characters on the basis of biosynthetic complexity and on correlated frequencies of occurrence with morphological and anatomical features. The evolutionary significance of distribution patterns of proanthocyanidins, glycosylflavones, biflavonoids, 6- and 8-hydroxyflavonoids and anthocyanins is discussed in turn. The importance of these various distribution patterns is considered in relation to an ecological function for these flavonoids.  相似文献   

9.
Phymosomatoid echinoids from the Campanian and the Maastrichtian of Belgium and the Netherlands are systematically revised. Ten species, belonging to four genera are identified and described. One new species is introduced:Gauthieria?mosae sp. nov.  相似文献   

10.
Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor  相似文献   

11.
Two Triassic sphenodontid reptiles, Brachyrhinodon taylori and Polysphenodon mulleri , are redescribed. Both genera are blunt-snouted forms but, as a result of distortion in the original fossils, the degree to which the snouts are shortened has previously been over-elaborated. An elongate temporal region and an interorbital width exceeding that of the parietal table are both derived characters in sphenodontids. Polysphenodon is plesiomorphic for both conditions, whereas Brachyrhinodon displays the derived states. Therefore, it is assumed that the reduced snout has been independently derived in each genus. The limb elements of Polysphenodon are long relative to the size of the skull and are similar in proportions to some species of Homoeosaurus. This resemblance is considered to be indicative of similar locomotory requirements rather than close evolutionary relationships. Cladograms showing possible interrelationships within the Sphenodontida are based on twenty-nine character states.  相似文献   

12.
Summary The alterations which occur in the thymus of young-adult, male Osborne-Mendel rats during the acute involution induced by subcutaneous administration of hydrocortisone, are studied by light and electron microscopy.A progressive loss of body weight of the treated animals is registered during the first days of the experiments. It lasts several days before the starting body weights are regained. Maximal thymus weight reduction is found on the fifth day after one dose (series I) and on the third day after two doses (series II).The most important light microscopic alterations observed in the different thymic cellular components are summarized in a table and illustrated.By electron microscopy severe damage of the nuclei of small lymphocytes is seen shortly after the hormonal treatment. In particular, this damage includes the margination and condensation of the chromatin. Later, the nuclei become completely dense and show fragmentation and/or lobulation. Budding of the lymphocytes is repeatedly observed. When nuclear changes are advanced, solitary, dense particles, presumed to be of RNA nature, and focal accumulation of osmiophilic material are seen in the cytoplasm. The latter findings are correlated with those made by other investigators on isolated polysomes.In the epithelial cells of the reticular type the number of smooth profiles of endoplasmic reticulum and of vacuole like structures, which completely can be filled with osmiophilic material, is augmented. In between the epithelial cells moderately electron-dense material is deposited. Pictures which suggest phagocytic activity by epithelial cells are found. Cysts lined with epithelial cells, which manifest secretory activity, are encountered in the later stages.The mesenchymal reticular cells are marked by phagocytosis of damaged lymphocytes, which undergo further intracytoplasmic digestion, and by lipid accumulation. In this respect, the close association of smooth endoplasmic profiles with the lipid droplets is emphasized. At the later intervals, big foamy cells stuffed with lipid inclusions, whose substructure varies considerably, and cleft-like spaces predominate. Attention is drawn to the proliferation of smooth-surfaced lamellae and small tubules in cells which presumably are of mesenchymal nature. The exact role and significance of these proliferations cannot yet be defined.The number of mast cells is increased in the interlobular septa and the capsule. Mast cells are not found within the thymic parenchyma.The budding phenomenon of the lymphocytes and the unspecific character of the nuclear changes are discussed. Mechanisms which other investigators studying nuclear degeneration proposed to be responsible for the nuclear changes, are reported. Considerations on the fate of the phagocytosed material within the macrophages and the epithelial cells, are made. This problem forms part of our present work.  相似文献   

13.
The Asteraceae are commonly divided into two large subfamilies, the Cichorioideae (syn. Lactucoideae; Mutisieae, Cardueae, Lactuceae, Vernonieae, Liabeae, Arctoteae) and the Asteroideae (Inuleae, Astereae, Anthemideae, Senecioneae, Calenduleae, Heliantheae, Eupatorieae). Recent phylogenetic analyses based on morphological and chloroplast DNA data conclusively show that the Mutisieae-Barnadesiinae are the sister group to the rest of the family and that the Asteroideae tribes form a monophyletic group. The Vernonieae and Liabeae are sister tribes and the Eupatorieae are nested within a paraphyletic Heliantheae; otherwise tribal interrelationships are still largely uncertain. The Mutisieae-Barnadesiinae are excluded from the Mutisieae and elevated to the new subfamily Barnadesioideae. The two subfamilies Barnadesioideae and Asteroideae are monophyletic, whereas the status of the Cichorioideae remains uncertain. Analyses of chloroplast DNA data support the monophyly of the Cichorioideae; however, morphological data indicate that the subfamily is paraphyletic. Further studies are needed to test the monophyly of the Cichorioideae, as well as to further resolve tribal interrelationships in the two larger subfamilies.  相似文献   

14.
Summary Epithelial structures in the olfactory region of the frog and the toad have been examined with the aid of light and electronmicroscopy. The olfactory cells send out 6–12 extremely long cilia with a central fibrillar structure and a peripheral sheath. They are motile but only in a small degree as their peripheral ends are weaved together in a network which covers the epithelial surface. The sustentacular cells show a great number of small protoplasmic protrusions on their surface. Their importance is discussed.The cells of the glands of Bowman are also provided with small protoplasmic protrusions but they are smaller than those of the sustentacular cells and do not show their inner structures. In all three celltypes mitochondria were found containing systems of double-membranes and in the supporting cells and Bowman's cells intracellular cytoplasmic membranes were observed.  相似文献   

15.
Hawkins  S.J.  Corte-Real  H.B.S.M.  Pannacciulli  F.G.  Weber  L.C.  Bishop  J.D.D. 《Hydrobiologia》2000,440(1-3):3-17
The special features of the intertidal ecosystems of remote islands are reviewed briefly before focusing on the littoral zone of Macaronesia (Azores, Madeira and Canaries). Distribution patterns are briefly compared with other European shores. Species missing from the Azores compared with Madeira, the Canaries and continental European shores are listed. The degree of genetic differentiation within and amongst selected important species of gastropods (Patella spp.) and barnacles (Chthamalus spp.) in Macaronesia is reviewed. The role of isolated islands in allopatric speciation of these organisms is discussed in relation to dispersal. Possible threats to the populations and communities of rocky shores in Macaronesia are considered in the context of the endemic nature of certain species. The importance of studies of basic ecology and genetics to inform resource management and conservation is highlighted. Future research directions are indicated, emphasizing the usefulness of Macaronesia as a model system to explore speciation in intertidal organisms.  相似文献   

16.
Injection of adrenergic and cholinergic agents to animals in the normal athmospheric conditions did not tigger drastic changes on the electric activity of the brain and heart. Acutehipoxia demands high adaptability from the body. In such conditions stimulation of reticular formation and hypothalamus produces different changes in the EEG and ECG activity whith injecting adrenergic and cholinergic agents. It was determined that cholinergic influence are effective in the regulation of electrical brain activity while adrenergics are more important for the realization of descending influences of the truncus cerebri vegetative centers and are less active in the modulation of the cerebral cortex activity.  相似文献   

17.
The fundamental ideas of the phoronomics of the entropy are developed. There are some important kinematic quantities and three kinematic decompositiones.  相似文献   

18.
Summary A combined light- and electron microscopic study of the normal thymus of young-adult, male Osborne-Mendel rats and, to a lesser extent, of young (8 days) and older (7–8 months) animals has been made. The data obtained provide a base line for submicroscopic investigations being in progress of the thymus in pathological conditions (acute involution followed by regeneration and virus-induced tumours). In addition, attention is given to the question whether the various thymic components show morphological signs which could represent secretory activity.Two main types of cells with epithelial characteristics (desmosomes, tonofilaments, basal membrane) are distinguished on the basis of their form, location and cytological features. The reticular type is most frequent in the cortex and contains round, clear structures partly filled with dense and/or membranous material. The cisternae of the endoplasmic reticulum frequently are dilated. The other cell type which only is present in the medulla, shows a more polygonal form. The clear cytoplasm is marked by an abundance of vesicles, golgi complexes and clusters of vacuoles provided with microvilli.The submicroscopic findings in the lymphocytes confirm in general previous reports. The nucleus of the large lymphocytes contains one or two faintly defined nucleoli. The nuclear pores show an inner clear zone with a central knob. The relatively large cytoplasm is studded with polyribosomes; a small band beneath the plasma membrane is devoid of organelles. The chromatin material in the nucleus of the small lymphocytes is condensed at the periphery and in the center; nucleoli are rare. Well developed golgi apparatuses with centrioles are present; multivesicular bodies and lysosomes are not invariably found. The intranuclear formation of mitochondria was never encountered. Interruptions of the cell membrane and cytoplasmic fragmentation are observed. Different phases of the mitotic cycle of the thymocytes are illustrated. Evidence of epithelial cell lymphocyte transformation cannot be given by the study of normal tissue.Mesenchymal reticular cells with or without evident phagocytic activity are described and can be regarded as representing different types.The number of plasma cells increases with age. The endoplasmic cisternae of some of them contain a material which is condensed in a crystalline form and probably represents proteins.The tubular structures which usually are located at the periphery of the thymic lobuli also have been examined. The epithelial cells lining these structures show irregular microvilli and the intracytoplasmic granules as well as the vacuoles and the well developed endoplasmic reticulum are supposed to be signs of a secretory activity. Moderately dense material condensed in a crystalline form is present in the tubular lumina; the significance is not clear, however.Many small cortical bloodvessels are only partly enclosed by epithelial cells and the lymphocytes lie nearly in direct contact with the endothelial basement membrane. These findings are discussed in relation to the existence of a thymus-blood barrier as proposed in other reports.  相似文献   

19.
In order to analyze the complicated movements of the mandible as the open-closing movement and the protrusio are, it is useful to evaluate the basic kinematic principles and reduce them to simple technical constructions. Both the open-closing movement and the protrusio could be reduced to 4-bar links, which were used to simulate the movements with help of a computer. Besides, the polodes and the curves of points in the muscular attachments could be constructed. The 2 entirely different 4-bar links have 3 things in common: The resting system - cranium, the moving system - mandibula, and 1 of the 2 arms connecting these 2 systems - the ligamentum laterale. As this ligament is taut during movements it can be considered a "guiding ligament" representing 1 of the 3 determining components of the mandibular movements. The other of the 2 arms has no anatomical equivalent; this arm, however, is "replaced" by the 2 other determining components of the mandibular movements: the joint and the muscles. The curves, which the Caput mandibulae describes, are practically identical for the open-closing movement and the protrusio despite of the different 4-bar links and these curves exactly correspond to the Discus articularis, taut by the upper part of the M. pterygoideus lateralis. The muscles do not only just move the mandibula, but they are also the component, which can choose between the different mandibular movements. By means of the curves, which points in the muscular attachments describe, the function of the masticatory muscles could be analyzed exactly.  相似文献   

20.
Age and local changes of the lymphatic bed have been studied in the jejunum and ileum preparations obtained from 100 rabbits. The architectonics of the bed is stated to undergo some age and local changes. In fetuses and two-week-old rabbits, chyle sinuses are narrow and all flow into the capillaries of the tela submucosa. In one-month-old animals, the mucosal capillary network is developing and the chyle sinuses flow into it. In six--ten-month-old rabbits, intestinal bed is already formed, the chyle sinuses are wide. Aged changes are represented by a considerably rarefied networks, decrease in the chyle sinuses caliber, deformation of the sinus, capillary and vessel walls. In the jejunum, unlike the ileum, the chyle sinuses are of larger size and have more complex architectonics in the capillary networks of the mucosa and tela submucosa.  相似文献   

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