首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A new species ofNeosartorya, N. sublevispora (anam.Aspergillus sublevisporus), is described and photographed. The species is characterized by non-ostiolate ascomata covered loosely with a pale yellowish hyphal envelope, lenticular ascospores with two low equatorial crests, and subglobose to ellipsoidal, microtuberculate conidia. The ornamentation of ascospores, which is composed of two closely appreassed crests and small even-sized echines on their convex surfaces, particularly serves to distinguish this species from other recognized species. A revised key to all accepted species of the genus is provided.  相似文献   

2.
The neuronal organization of the accessory olfactory bulb (AOB), which receives sensory information from the vomeronasal organ, was described in a squamate reptile (Podarcis hispanica) by means of light microscopy. Using the Golgi-impregnation method, seven neuronal types could be distinguished: Periglomerular cells constitute a morphologically heterogeneous population of small neurons located between and around the glomeruli. The mitral cells are diffusely distributed in the AOB. Their cell bodies are usually located within the mitral cell layer, but some of them could be also observed in the plexiform layers. Mitral cells were classified into three subgroups on the basis of their sizes and dendritic tree morphologies. Thus, the “outer mitral cells” have the biggest cell bodies, and their distal secondary dendrites are mainly distributed rostrocaudally in the external plexiform layer. The “inner mitral cells” have large cell bodies, and their secondary dendrites are distributed dorsoventrally and are located deeper than those of the other two subgroups. The third type, the “small mitral cells,” is the smallest one among mitral cells in the AOB, and from their cell bodies, only two main dendritic trunks arise. The granule cells are composed of several categories based on their different cell body locations and dendritic tree morphologies. Thus, the “superficial granule cells” are located exclusively in the external plexiform layer and have small dendritic fields. The “middle granule cells” have fusiform cell bodies—situated in the internal plexiform layer—and present a wide dendritic projection area. Finally, the “deep granule cells” are distributed throughout the granule cell layer and include a great variety of dendritic tree morphologies. The distribution and morphological features of all neuronal types constituting the AOB of Podarcis were compared with those reported on other vertebrates. The results suggest that the lamination pattern and neuronal organization of the AOB in lizards are more similar to that of mammals than to that of the remaining vertebrates.  相似文献   

3.
Fishelson, L., Golani, D., Russell, B., Galil, B. and Goren, M. 2012. Comparative morphology and cytology of the alimentary tract in lizardfishes (Teleostei, Aulopiformes, Synodontidae). —Acta Zoologica (Stockholm) 93 : 308–318. This study compares the morphology and cytology of the alimentary tract in several species of lizardfishes (Synodontidae, Teleostei) of the genera Saurida, Synodus, and Trachinocephalus, in relation to their diets and bathymetric distribution. All the studied species feature a large, pouch‐like stomach, with the intestine beginning at the stomach’s anterior apex, adjacent to the esophageal opening. In the more ‘microphagous’Synodus spp. and Trachinocephalus, the intestine bends twice before reaching the anus, whereas in the more ‘macrophagous’Saurida spp., the intestine extends straight to the anus. The species differ also in the number and form of their pyloric ceca, the length of the intestine and in the percentile relationship between stomach length and standard body length. Along the alimentary tract folds and villi protrude into the lumen, their numbers differing on various sites of the tract. Three cell types make up the gastric gland system: (1) pyramidal cells forming the tubular gastric glands in the lamina propria; among them are large, pale secretary cells; (2) groups of neck cells that surround the pits of the tubules; and (3) groups of large and granule‐rich cells at the end portion of the stomach. All species are carnivorous and uniform in morphology, the differences in the alimentary tract found between the more shallow‐water species of Synodus and Trachinocephalus, and the deeper‐dwelling Saurida, seem to be only partly correlated with the differences in diet.  相似文献   

4.
The architecture and fine structure of the epigastric hematopoietic nodules of the ridgeback prawn, Sicyonia ingentis, are described. The nodules consist of a highly branched series of tubules that contain the maturing hemocytes within a connective tissue stroma. Hemocytes can exit the hematopoietic nodules by penetrating through fenestrations in the endothelial cell layer into the central hemal space or by migrating through the outer later of capsular cells and associated collagen fibrils. Four hemocyte categories were observed: agranular, small granule with cytoplasmic deposits, small granule without cytoplasmic deposits, and large granule hemocytes. This classification was based upon the presence, size, and type of cytoplasmic granules and the presence of cytoplasmic deposits. Only agranular cells and small granule hemocytes without cytoplasmic deposits appeared capable of division. Intermediate stages were observed between agranular hemocytes and small granule hemocytes with deposits and between small granule hemocytes without deposits and large granule hemocytes, suggesting existence of two distinct hemocyte lines.  相似文献   

5.
The hemocytes of two palaemonids and one penaeid were characterized using light and transmission electron microscopy (TEM). The blood cells in all three species were classified as hyaline hemocytes (HH), small granule hemocytes (SGH), and large granule hemocytes (LGH). The HH are unstable hemocytes with a characteristic high nucleo-cytoplasmic ratio. Their cytoplasm appears particularly dense and has from few to numerous granules that often exhibit a typical striated substructure. In both palaemonids, the great majority of the HH contain numerous granules, whereas in Penaeus paulensis, a small number of these cells have few or no granules. The cytoplasm of some HH of the penaeid exhibits typical electron-dense deposits. The granulocytes, LGH and SGH, contain abundant electron-dense granules that are usually smaller in the SGH. In both hemocyte types, the cytosol, but not the granules, is rich in carbohydrates (PAS positive) and numerous vesicles contain acid phosphatase (Gomori reactive). In all studied shrimps, the SGH and LGH were actively phagocytic when examined on blood cell monolayers incubated with the yeast Saccharomyces cerevisiae. A few mitotic figures (less than 1%) were observed in the granulocytes of P. paulensis, but not in the palaemonids. SGH is the main circulating blood cell type in both palaemonids, whereas HH is predominant in the penaeid. Based on morphological and functional features, it appears that the hyaline and the granular hemocytes of the three shrimp species represent different cell lineages. J. Morphol. 236:209–221, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

6.
Three new species of Agaricales are described and illustrated from eastern Honshu, Japan:Collybia effusa sp. nov. (sectionLevipedes), forming a distinctly sulcate-striate pileus and distant lamellae, was found on dead twigs ofCryptomeria japonica andCallicarpa japonica; Collybia macrosperma sp. nov., forming cylindrical-fusoid, relatively large-sized basidiospores and whitish basidiomata densely covered with fine, soft hairs, was found on dead fallen twigs in aCarpinus andQuercus forest:Marasmiellus, gregarius sp. nov (subsectionRamealini of sectionRameales), forming small, pale colored pilei and diverticulate cheilocystidia, was found on dead twigs ofHydrangea involucrata andTrachelospermum asiaticum.  相似文献   

7.
We used the egg avidin gold complex as a polycationic probe for the localization of negatively charged sites in the secretory granules of mouse mast cells. We compared the binding of this reagent to mast cell granules in wild-type mice and in congenic brachymorphic mice in which mast cell secretory granules contained undersulfated proteoglycans. We localized anionic sites by post-embedding labeling of thin sections of mouse skin and tongue tissues fixed in Karnovsky’s fixative and OsO4 and embedded in Araldite. Transmission electron microscopy revealed that the mast cell granules of bm/bm mice had a lower optical density than those of wild-type mice (P<0.001) and a lower avidin gold binding density (by approximately 50%, P<0.001). The latter result provided additional evidence that the contents of mast cell granules in bm/bm mice were less highly sulfated than in those of wild-type mice. In both wild-type and bm/bm mast cells, the distribution of granule equivalent volumes was multimodal, but the unit granule volume was approximately 19% lower in bm/bm cells than in wild-type cells (P<0.05). Thus, bm/bm mast cells develop secretory granules that differ from those of wild-type mice in exhibiting a lower optical density and slightly smaller unit granules, however the processes that contribute to granule maturation and granule-granule fusion in mast cells are operative in bm/bm cells.  相似文献   

8.
The contributions of different groups of loci, namely those identical (i), similar (s), and different (d) with respect to allele composition and the loci expressed in only one of two compared objects (0), into the differentiation of marsupial and placental mammals have been evaluated. An increase in the proportions of d and 0 loci with increasing taxon rank has been demonstrated. At the intraspecific level, identical loci are prevailing, and d loci are rare; the latter are more common in subspecies. At the species level, the proportions of different (d) and similar (s) loci are increased, but the proportion of i loci is still the highest. Only at the genus level does the proportion of different loci reach 41–49%; 0 loci are found in marsupials and small placental mammals, and the number of s loci is decreased. In large placental mammals, this trend is disrupted at the subspecies level, where the contribution of s loci is drastically increased, while the proportion of identical ones (i) is decreased. Comparison with data on other groups of vertebrates shows that the ratios between these groups of loci reflect the specificity of differentiation processes at the intraspecific level and the levels of species and taxa of higher ranks in all classes of animal analyzed. However, the species differentiation in amphibians approximately corresponds to the genus level in mammals and the family level in birds.  相似文献   

9.
Abstract A new species of Culicoides, C. tahemanensis sp. nov. is described from Xingjiang Uygur Aut. Reg. in China. The new species is closely allied to Culicoides grisescens Edwards, but both of them are distinctly different in pale spots of cell R5 and cell A of wing of female, and shape of distal portion of aedeagus of male. The ninth tergum of new species is somewhat allied to C. nipponensis Tokunaga, but distinctly different in pale spots of cell R5, cell M2 and cell A of wing, and shape of aedeagus of male. The type speciemens are deposited in the Institute of Military Medical Sciences, Shenyang Military District, Shengyang 110034, China.  相似文献   

10.
The hypothalamus of the opossum (Didelphis virginiana), the armadillo (Dasypus novemcinctus mexicanus), and the cat (Felis domestica) was studied using Del Rio Hortega's silver carbonate technique, as modified by Scharenberg ('60). This technique demonstrates astrocytes, oligodendroglia, and neuronal perikarya, but does not impregnate microglia. The morphology of macroglia was observed in ten comparable nuclei in each of the three species. The subpial and subependymal areas were also examined. Astrocytes display more cell body angularity and have more processes in most hypothalamic regions of the cat when compared to similar regions of the opossum and armadillo. In the anterior hypothalamic nucleus, the ventromedial and the dorsomedial hypothalamic nuclei, and the medial mammillary nucleus of all three species, astrocytes send processes to neurons, but neuronal and astrocytic perikarya are usually not directly contiguous. However, oligodendrocytes in a perisomatic position on neurons are a consistent feature in these nuclei. A closer relationship appears to exist between astrocytes and neurons in the neurosecretory nuclei. In the supraoptic nucleus and paraventricular nucleus of all three species a basket-like structure, designated a ?pericellular envelope”? was observed surrounding neuronal perikarya. This structure is composed of astrocytic and oligodendroglial cell bodies and processes, and is most highly developed in the cat. A dense astrocytic plexus was observed in the suprachiasmatic nucleus of the cat, and in the comparable nuclei of the armadillo and opossum. The most prominent macroglial cell type of the lateral hypothalamic and lateral mammillary nuclei of all three species is the interfascicular oligodendrocyte. The posterior hypothalamic nucleus of each species has many perisomatic oligodendrocytes, and in the armadillo and cat astrocytes are closely related to the larger neurons. A subpial plexus, consisting of a palisade of small glial cells with many processes, is present in the hypothalamus of the three species. Ependymal cells have long projecting processes throughout the length of the third ventricle in the armadillo hypothalamus, but such processes are only apparent in the region of the infundibular nucleus and median eminence in the opossum and cat.  相似文献   

11.
Alstroemeria hygrophila andA. orchidioides are both described as new from the state of Goiás (including Distrito Federal) in Brazil.Alstroemeria hygrophila is a cerrado bog-dwelling species that grows semi-epiphytically on the culms of a sedge. The vegetative stems of this species characteristically zig-zag between the pseudonodes. Like other wetlandAlstroemeria in Brazil (e.g.,A. apertiflora, A. isabellana, andA. sellowiana),A. hygrophila has wiry stems bearing narrow, lanceolate, nonresupinate leaves, and does not form root tubers.Alstroemeria orchidioides is a hysteranthus forest understory species with large vegetative leaves aggregated at the apex of the stems. The leaves on flowering stems are reduced to scarious bract-like scales. Its flowers are a pale, nearly white, greenish yellow, a color not reported in any other Brazilian species. Both species have 2n=16 chromosomes.  相似文献   

12.
Three new species of Agaricales are described and illustrated from eastern Honshu, Japan:Agrocybe pseudoerebia sp. nov. (sectionVelatae of subgenusAporus), forming fugaceous veil remnants around the pileal margin and relatively shorter basidiospores (less than 10 μm long) without a germ pore, was found on the ground in a broad-leaved forest;Lactarius glutininitens sp. nov. (sectionTriviales of subgenusRussularia), forming a pale grayish, strongly glutinous pileus and watery, latex without discoloration, was found on the ground in a lowland forest dominated byQuercus myrsinaefolia andQuercus serrata; Tricholoma foliicola sp. nov. (close to sectionAlbobrunnea), forming a reddish brown, hygrophanous, dry, glabrous pileus, almost adnate, densely crowded lamellae, small, ellipsoid basidiospores, and clampless hyphae, was found on leaf litter of a broad-leaved forest.  相似文献   

13.
H. Takahashi 《Mycoscience》2002,43(4):0343-0350
 Four new species of Crinipellis and Marasmius (Agaricales, Basidiomycetes) in eastern Honshu, Japan, are described and illustrated: (1) Crinipellis conchata sp. nov. (section Excentricinae), forming a conchate pileus and a strongly excentric, short stipe, was found on a dead twig of Trachelospermum asiaticum in Mt. Takao, Tokyo; (2) Marasmius funalis sp. nov. (section Androsacei), forming a densely white-hispid, dark brown stipe bearing numerous setiform caulocystidia, was found on a dead twig of Cryptomeria japonica or on leaf litter in Tokyo and Kanagawa; (3) Marasmius maculosus sp. nov. (section Sicci), having a relatively large, reddish-brown pileus distinctly mottled with pale colored spots and Siccus-type cheilocystidia and pileipellis cells with relatively long setulae, was found on leaf litter in the lowland forest of Kanagawa and Chiba; and (4) Marasmius sasicola sp. nov. (section Marasmius), having a small, plicate-sulcate pileus, a filiform, wiry, blackish stipe, collariate lamellae, and Siccus-type cheilocystidia and pileipellis elements, was found on fallen dead leaves of grass bamboo in Kanagawa. Received: January 30, 2002 / Accepted: May 24, 2002  相似文献   

14.
Although pollinators are thought to select on flower colour, few studies have experimentally decoupled effects of colour from correlated traits on pollinator visitation and pollen transfer. We combined selection analysis and phenotypic manipulations to measure the effect of petal colour on visitation and pollen export at two spatial scales in Wahlenbergia albomarginata. This species is representative of many New Zealand alpine herbs that have secondarily evolved white or pale flowers. The major pollinators, solitary bees, exerted phenotypic selection on flower size but not colour, quantified by bee vision. When presented with manipulated flowers, bees visited flowers painted blue to resemble a congener over white flowers in large, but not small, experimental arrays. Pollen export was higher for blue flowers in large arrays. Pollinator preference does not explain the pale colouration of W. albomarginata, as commonly hypothesized. Absence of bright blue could be driven instead by indirect selection of correlated characters.  相似文献   

15.
Summary The ultrastructural localization of peroxidase (PO) in the leucocytes of three teleosts (Cyprinus carpio L., Tinca tinca L., Salmo gairdneri R.) has been investigated using the 3,3-diaminobenzidine method. In the heterophilic granulocytes the granules show a species specific structure and are PO-positive at pH 7.6. They can be traced back to small granules arising near the Golgi apparatus (GA) in the promyelocyte. They coalesce to form larger granules and gradually change into the mature type. Myelocytes contain small unreactive granules, and these represent a second granule population. Eosinophils contain one PO-positive granule type (at pH 9), and these granules show a varying density during cell maturation.Basophils are present only in the Cyprinid species, and contain unreactive granules originating from precursors displaying a weakly positive reaction at pH 7.6. The active secretory organelles (RER, GA) are PO-negative, except for a weakly positive reaction in the flocculent matrix of the inner G-cisternae.In promonocytes and monocytes the granules are unreactive, but in the macrophages PO-positive staining occurs in a few small to medium sized granules, and in large vacuoles. At least some of these latter are apparently derived from phagolysosomes containing digested erythrocytes. Thrombocytes and lymphocytes are unreactive.The successive development of PO-positive and negative granule populations in the heterophils, and the PO-reactivity of eosinophils and basophils, show some similarities to the corresponding cells in higher vertebrates, but an analogous PO-positive (azurophil) granule type in monocytes seems to be absent.  相似文献   

16.
The morphology of strains of Skeletonema Greville emend Sarno et Zingone was examined in LM, TEM, and SEM and compared with sequence data from nuclear small subunit rDNA and partial large subunit rDNA. Eight distinct entities were identified, of which four were known: S. menzelii Guillard, Carpenter et Reimann; S. pseudocostatum Medlin emend. Zingone et Sarno; S. subsalsum (Cleve) Bethge; and S. tropicum Cleve. The other four species were new: S. dohrnii Sarno et Kooistra sp. nov., S. grethae Zingone et Sarno sp. nov., S. japonicum Zingone et Sarno sp. nov., and S. marinoi Sarno et Zingone sp. nov. Skeletonema species fell into four morphologically distinct groups corresponding to four lineages in the small subunit and large subunit trees. Lineage I included S. pseudocostatum, S. tropicum, S. grethae, and S. japonicum. All have external processes of the fultoportulae with narrow tips that connect with those of sibling cells via fork‐, knot‐, or knuckle‐ like junctions. Lineage II included only the solitary species S. menzelii. Lineage III comprised S. dohrnii and S. marinoi. This latter pair have flattened and flared extremities of the processes of the fultoportulae, which interdigitate with those of contiguous valves without forming knots or knuckles. Lineage IV only contained the brackish water species S. subsalsum. Some species also differ in their distribution and seasonal occurrence. These findings challenge the concept of S. costatum as a single cosmopolitan and opportunistic species and calls for reinterpretation of the vast body of research data based on this species.  相似文献   

17.
Ultrathin sections were studied in 2 strains and 2 samples from the nature of the genusChamaesiphon, representing 4 different species. Thylakoids are distributed mainly on the periphery of the cells, the cell-wall is probably 2-layered, and variable multilayered mucilaginous envelopes are developed around the cells. The cell division starts, as well as in otherCyanophyceae, by the invagination of the cytoplasmic membrane and of cell-wall layers into the protoplast; the mucilaginous envelopes—pseudovaginae—do not participate in this process but they form only the firm sheaths around the cells. The way of reproduction is, therefore, essentially the same as that described in other chroococcal Blue-Green algae (e.g.,Synechococcus), and the main difference is the polarized growth of theChamaesiphon cells. The taxonomical position of chamaesiphonoid algae is not as isolated as it was earlier supposed, the similarity withEntophysalidaceae is evident.  相似文献   

18.
Entoprocta is a group of mostly cryptic, benthic invertebrates with a sedentary lifestyle. Here, we investigate the morphology of the entoproct foot, which is an important structure in attachment and locomotion. We describe the foot structure of four solitary entoprocts, Loxosoma monilis, Loxosomella stomatophora, Loxocorone allax, and Loxomitra mizugamaensis, by means of light and transmission electron microscopy. Gland cells containing secretory granules were found in the foot of all the four species. In L. monilis, the gland cells densely paved the underside of the disc‐shaped foot, but no duct or groove was found. In L. stomatophora and L. allax, a foot gland was present at the frontal end of a foot groove. The foot gland was a solid cell mass in the former species but a sac‐like structure in the latter. Two types of groove accessory cells were recognized in both species; groove bulge cells (GBCs) showed large cytoplasmic bulges extending into the groove lumen, while groove microvillus cells have microvillus mats in the lateral wall of the groove. The bulges of GBCs in L. stomatophora are slender and attached to one another with desmosomes, forming appendages that extend down to the substratum, hinting at their contribution to attachment and locomotion. The bulges in L. allax form large swellings that fill the groove lumen and are connected to the surrounding cells with hemidesmosomes. In the liberated buds of L. mizugamaensis, tripartite gland cell masses were found at the basal end of the stalk, but no groove was found. A small invagination, which may be the opening of the gland, was found at the center of the foot tip, where the liberated buds attach themselves to the substratum and then metamorphose into adults. No openings were found at the lateral terminal wings, which support locomotion in Loxomitra species. J. Morphol. 271:1185–1196, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

19.
Two onygenalean fungi isolated from forest soil in the Sikhote-Alin reserve, Russian Far East (east Siberia), are described and illustrated:Gymnostellatospora parvula as a new species andAphanoascus canadensis as a new record.Gymnostellatospora parvula is characterized by psychrophilic growth, pale yellow to pale cinnamon ascomata with a hyphal peridium, small, hyaline discoid ascospores with an equatorial rim and more or less longitudinally ridged wall.  相似文献   

20.
Felicia Keesing 《Oecologia》1998,116(3):381-389
The impacts of ungulates on small mammals in an East African savanna habitat were investigated by monitoring the population and community responses of small mammals on replicated 4-ha plots from which ungulates had been excluded. The dominant small mammal in this habitat is the pouched mouse, Saccostomusmearnsi, a medium-sized murid rodent. Eight other small mammal species, including Arvicanthis sp., Mus sp., Mastomys sp., Dendromus sp., Crocidura sp., and, rarely, Tatera sp., Aethomys sp., and Acomys sp., were also captured. The dominant ungulates are elephant (Loxodonta africana), giraffe (Giraffa camelopardalis), Grevy's and common zebra (Equus grevyi and E. burchelli), buffalo (Syncerus cafer), eland (Taurotragus oryx), Grant's gazelle (Gazella granti), and domestic cattle. Within 1 year, S. mearnsi populations had responded dramatically to the exclusion of large mammals by a two-fold increase in density, a difference that was maintained through pronounced seasonal fluctuations in the second year. Though individual pouched mice showed no significant differences in their use of space with and without ungulates, male S. mearnsi maintained significantly higher body weights in the absence of ungulates, indicating that habitat quality had increased. One other species, Mastomys sp., also increased in the absence of ungulates. Overall, the small mammal community maintained relatively constant species diversity on the plots to which ungulates did not have access. On the plots to which ungulates did have access, on the other hand, there was a rapid 75% decrease in diversity in the control plots during one trapping session. Ungulates are most likely affecting small mammals through their effects on food quality, since there were no detectable differences in their exposure to predators, as determined by vegetative cover, in the absence of ungulates. These results demonstrate that ungulates can have strong and rapid impacts on small mammal abundance and diversity in East African savannas, an interaction which has not previously been given serious consideration. Received: 28 December 1997 / Accepted: 11 May 1998  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号