共查询到20条相似文献,搜索用时 15 毫秒
1.
Priv.-Doz. Dr. Erwin Tretzel 《Zoomorphology》1961,50(4):375-542
Ohne ZusammenfassungZweiter Teil der Habilitationssehrift. 相似文献
2.
Heregulin-α (HRGα) is a cytokine secreted by the mammary mesenchyme, adjacent to lobuloalveolar structures. To understand
the role of HRGα and its receptors in mammary glands, and the underlying mechanisms, we performed this study to determine
the expression and localization of HRGα and its receptors ErbB2 and ErbB3. We also determined the role of HRGα in the development
of mammary glands, β-casein expression and secretion, Rab3A protein expression and the phosphorylation of HRGα signaling molecules
using confocal laser scanning microscopy, tissue culture, capillary electrophoresis, Western blotting and enzyme-linked immunosorbent
assays. We found that a peak was on pregnancy day 15. Changes of ErbB2 and ErbB3 expression were positively and linearly correlated
with HRGα, indicating that HRGα positively regulates ErbB2 and ErbB3 expression. During pregnancy, HRGα enhanced the phosphorylation
of STAT5, p42/p44, p38, PKC and Rab3A protein expression, stimulated the proliferation and differentiation of the ductal epithelial
cells of mammary glands, and increased and maintained the expression and secretion of β-casein. During lactation, HRGα enhanced
the phosphorylation of STAT5 and p38, inhibited the phosphorylation of PKC and Rab3A protein expression, maintained the morphology
of the mammary glands and increased the secretion of lactoprotein to reduce the expression of β-casein in mammary epithelial
cells. During involution, HRGα induced the phosphorylation of STAT3 and Rab3A protein expression, and inhibited the phosphorylation
of PKC to stimulate the degeneration of mammary epithelial cells. It also inhibited the secretion of β-casein, resulting in
increased levels of β-casein in mammary epithelial cells. 相似文献
3.
K. A. Mikrjukov 《Protoplasma》1995,188(3-4):186-191
Summary A study of the structure, function, and development of extrusive organelles (microtoxicysts) in the unusual bacteriovorous rhizopodPenardia cometa is performed. Microtoxicysts are located in the cortical cytoplasm of the cell body and in special thickenings on reticulopodia. Similar types of extrusomes have been observed in some cercomonads. The microtoxicysts are organized as membrane-bound vesicles of a complex form. An oviform-conical axial element lies inside each vesicle and is directed with its narrower end towards the plasma membrane. An internal cylindrical tube occupies the central part of the axial element; it is turned out as the organelle is shot out. The extrusomes ofP. cometa originate from and develop in derivates of the endoplasmic reticulum, the initial diameter of proextrusome vesicles is twice the diameter of the mature organelles. At late stages of maturation the microtoxicysts adopt their characteristic form and orientation. The mode of construction, ejection and development is compared with that in some other carnivorous and bacterivorous protists. 相似文献
4.
D. N. Young 《Protoplasma》1978,94(1-2):109-126
Summary Clusters of small, pyriform gland or vesiculate cells protrude from the inner cortex into the inflated bladders ofBotryocladia pseudodichotoma. These multinucleate cells contains a large, central vacuole surrounded by dense cytoplasm. The lobed chloroplasts lack phycobilisomes and contain concentric rather than parallel thylakoids. Irregularly shaped, osmiophilic bodies of undetermined composition are abundant in the cytoplasm and are also released into the vacuole. The cell is characterized by abundant Golgi apparatus. The Golgi bodies appear to form by coalescence of endoplasmic reticulum derived vesicles and tubules. The Golgi apparatus produces large, electron transparent vesicles that contain an osmiophilic, fibrous material. This material is secreted into a diffuse wall layer which appears to be continually sloughed. Thus, the vesiculate cells ofBotryocladia possess an ultrastructure characteristic of granulocrine secretory cells, and it is suggested that they produce the slime contained within the bladders of this genus. 相似文献
5.
The sting is the most effective defense of social Hymenoptera against vertebrate predators but in the hover wasps (subfamily Stenogastrinae) it is scarcely used. In these wasps a quite enlarged Dufour’s gland and the extensive use of its secretion in the peculiar rearing of the larvae and defense determined important morphological modifications of the sting structure. Connecting anatomical and morphological data with behavioral observations we determined that in these wasps the Dufour’s gland secretion is attached to the egg during oviposition but can be also channeled to the outside via the sting when it is collected by adult females for larval rearing or construction of the nest ant guards. The anatomical modifications of the sting reduced the function of the sting as a defensive weapon in hover wasps. 相似文献
6.
Jennifer Whinam 《Polar Biology》1989,9(8):499-503
Summary The stratigraphy, hydrology and vegetation of the Heard Island (sub-Antarctic; 53°05S, 73°30E) pool complex bogs are described. Spatial variation in processes that might have contributed to their formation are discussed. This community occurs where drainage is impeded. with Callitriche antarctica being the indicator species. Particular attention is paid to the interaction of the vegetation, pools and animals. Surface stratigraphy, peat depth, water depth and vegetation composition were measured along transect lines. Species cover abundance data of 300 quadrats were classified using a two-way indicator species analysis program and ordinated using detrended correspondence analysis. The major factors determining vegetation composition were found to be peat depth, surface topography, and the degree and type of animal disturbance. Similarities between the pool complexes on Heard Island and corresponding bogs in Tasmania, and the northern hemisphere temperate and boreal zones appear to diminish as the density of the animals occupying this habitat increases. 相似文献
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8.
Yasushi Masuda Masayuki Okuyama Takahisa Iizuka Hiroyuki Nakai Wataru Saburi Taro Fukukawa 《Bioscience, biotechnology, and biochemistry》2016,80(3):479-485
Marine glycoside hydrolases hold enormous potential due to their habitat-related characteristics such as salt tolerance, barophilicity, and cold tolerance. We purified an α-glucosidase (PYG) from the midgut gland of the Japanese scallop (Patinopecten yessoensis) and found that this enzyme has unique characteristics. The use of acarbose affinity chromatography during the purification was particularly effective, increasing the specific activity 570-fold. PYG is an interesting chloride ion-dependent enzyme. Chloride ion causes distinctive changes in its enzymatic properties, increasing its hydrolysis rate, changing the pH profile of its enzyme activity, shifting the range of its pH stability to the alkaline region, and raising its optimal temperature from 37 to 55 °C. Furthermore, chloride ion altered PYG’s substrate specificity. PYG exhibited the highest Vmax/Km value toward maltooctaose in the absence of chloride ion and toward maltotriose in the presence of chloride ion. 相似文献
9.
Beatriz Appezzato-da-Glória Fernando Batista Da Costa Vanessa Cristina da Silva Leonardo Gobbo-Neto Vera Lucia Garcia Rehder Adriana Hissae Hayashi 《Flora》2012
Although the occurrence of glandular trichomes is frequently reported for aerial vegetative organs, many questions still remain opened about the presence of such trichomes in underground systems. Here, we present, for the first time, a comparative study concerning the structure, ultrastructure and chemical aspects of both, the aerial and underground glandular trichomes of two different Chrysolaena species, C. obovata and C. platensis. Glandular trichomes (GTs) were examined using LM, SEM, and TEM and also analyzed by GC–MS and HPLC coupled to UV/DAD and HR-ESI-MS (HPLC–UV–MS). In both aerial (leaf and bud) and underground (rhizophore) organs, the GTs are multicellular, biseriate and formed by five pairs of cells: a pair of support cells, a pair of basal cells, and three pairs of secreting cells. These secreting cells have, at the beginning of secretory process, abundance of smooth ER. The same classes of secondary metabolites are biosynthesized and stored in both aerial and underground GTs of C. platensis and C. obovata. These GTs from aerial and underground organs have similar cellular and sub-cellular anatomy, however the belowground trichomes show a higher diversity of compounds when compared to those from the leaves. We also demonstrate by means of HPLC–UV–DAD that the sesquiterpene lactones are located inside the trichomes and that hirsutinolides are not artifacts. 相似文献
10.
Eight species of Haplodrassus are recorded from Crimea: Haplodrassus bohemicus Miller & Buchar, 1977; Haplodrassus dalmatensis (L. Koch, 1866); Haplodrassus isaevi Ponomarev & Tsvetkov, 2006; Haplodrassus minor (O. P.-Cambridge, 1879); Haplodrassus kulczynskii Lohmander, 1942; Haplodrassus pseudosignifer Marusik, Hippa & Koponen, 1996; Haplodrassus signifer (C.L. Koch, 1839) and Haplodrassus umbratilis (L. Koch, 1866). The occurrence of Haplodrassus cognatus (Westring, 1861) in Crimea has not been confirmed. Haplodrassus bohemicus is a new species record for the Crimean fauna. Haplodrassus pseudosignifer is a new species record for Crimea and Ukraine as a whole, with Crimea as the westernmost point of its distribution range. Haplodrassus invalidus is recorded for the first time for the fauna of Azerbaijan, Caucasus and the former Soviet Union. Azerbaijan is the easternmost point of its known distribution range. All Crimean Haplodrassus species have only one peak of activity of adult specimens during the year. In Crimea we found syntopically two closely related species Haplodrassus dalmatensis and Haplodrassus isaevi in two localities (Sudak Distr., 10 km W Sudak, Mezhdurechie Vill., steppe; and Feodosiya Distr., Karadag Nature Reserve, steppes). These species differ in their phenology. The reproductive period of Haplodrassus dalmatensis isin May-July, and that of Haplodrassus isaevi occurs is in October-December. These phenological differences probably represent an additional mechanism of reproductive isolation between the two species. Diagnostic drawings are provided for all mentioned species as well as for Haplodrassus deserticola Schmidt & Krause, 1996 and Haplodrassus pugnans (Simon, 1880). 相似文献
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12.
Stefano Guariniello Giovanni Colonna Raffaele Raucci Maria Costantini Gianni Di Bernardo Francesca Bergantino Giuseppe Castello Susan Costantini 《Biochimica et Biophysica Acta - Proteins and Proteomics》2014,1844(2):447-456
In humans we know 25 selenoproteins that play important roles in redox regulation, detoxification, immune-system protection and viral suppression. In particular, selenoprotein M (SelM) may function as thiol disulfide oxidoreductase that participates in the formation of disulfide bonds, and can be implicated in calcium responses. However, it presents a redox motif (CXXU), where U is a selenocysteine, and may also function as redox regulator because its decreased or increased expression regulated by dietary selenium alters redox homeostasis. No data are reported in literature about its involvement in cancer but only in neurodegenerative diseases. In this paper we evaluated the SelM expression in two hepatoma cell lines, HepG2 and Huh7, compared to normal hepatocytes. The results suggested its involvement in hepatocellular carcinoma (HCC) as well as its possible use to follow the progression of this cancer as putative marker. The aim of this study has been to analyze the structure–function relationships of SelM. Hence, firstly we studied the evolutionary history of this protein by phylogenetic analysis and GC content of genes from various species. So, we modeled the three-dimensional structure of the human SelM evaluating its energetic stability by molecular dynamics simulations. Moreover, we modeled some of its mutants to obtain structural information helpful for structure-based drug design. 相似文献
13.
Brian Duff Sloley 《Neurochemical research》1994,19(2):217-222
The conversion of 5-hydroxytryptamine to several potential metabolites was examined in the annelid earthworm (Lumbricus terrestris). 5-hydroxytryptamine and some related amines were found to be present in several tissues of the earthworm. Injection of 5-hydroxytryptamine into the body cavity of the earthworm resulted in the production of a -glutamyl conjugate of 5-hydroxytryptamine. Incubations of the anterior nerve cord of the earthworm resulted in the accumlation of considerable amounts of 5-hydroxytryptamine and -glutamyl 5-hydroxytryptamine in the incubation medium. The earthworm did not produce any N-acetyl 5-hydroxytryptamine and only very little 5-hydroxyindoleacetic acid. Experiments involving the injection of radiolabeled 5-hydroxytryptamine or coninjection of radiolabeled glutamic acid with unlabeled 5-hydroxytryptamine into the earthworm resulted in the production of radiolabeled -glutamyl 5-hydroxytryptamine. This work demonstrates that the enzymatic conversion of 5-HT in the earthworm is markedly different from that of vertebrates and insects. 相似文献
14.
15.
《Biochemical Systematics and Ecology》2002,30(6):505-523
Mandibular gland secretions were investigated in 28 taxa of alloxystine wasps (17 described and 11 potential, hitherto undescribed species) using GC-MS. In two selected species (Alloxysta pleuralis, A. victrix), the chemical patterns of the mandibular gland secretions remained constant and were not qualitatively influenced by different host systems; however, there was a considerable variation in quantity. A cluster analysis revealed the chemical composition to be independent of two different modes of resource utilisation which are characterized by the presence or absence of ants in the respective host system. These results support the idea of the prevalence of historical (phylogenetic) rather than actual ecological constraints. However, the chemotaxonomic applicability of such data on the subfamily level was limited, although a species status could be confirmed in some questionable taxa. By integrating morphological and biological characters, potential relationships of selected species and a hypothetical phylogenetic frame tree are proposed. 相似文献
16.
Tamás Rőszer 《Cell and tissue research》2014,358(3):685-695
The immune system has an impact on the metabolic performance in vertebrates, thus the metabolic effects of immune cells are receiving intense attention today in the biomedical field. However, the evolutionary origin of the immunity–metabolism interaction is still uncertain. In this review, I show that mollusks and crustaceans integrate immune functions to a metabolic organ, the midintestinal gland (“hepatopancreas”). In these animals, the epithelial cells of the midintestinal gland are major sources of immune molecules, such as lectins, hemocyanin, ferritin, antibacterial and antiviral proteins, proteolytic enzymes and nitric oxide. There is crosstalk between midintestinal gland cells and phagocytes, which aids the initiation of the immune response and the clearance of pathogens. The midintestinal gland is thereby an integrated organ of immunity and metabolism. It is likely that immunity was the primary function of the midintestinal gland cells and that their role in the intermediate metabolism has evolved during the course of their further specialization. 相似文献
17.
《International Journal of Insect Morphology and Embryology》1998,27(3):255-261
The fine structure of the reproductive accessory gland of the parthenogenetic thrips Heliothrips haemorrhoidalis (Thysanoptera : Thripidae) is reported. It consists of an apical bulb and a fine gland duct. The former consists of an epithelium with secretory and duct-forming cells surrounding a large gland lumen lined with a thin cuticle and filled with dense secretion. Spent secretory cells degenerate and are eliminated from the epithelium. The gland duct is characterized by an irregular, branched lumen surrounded by a very flat epithelium. A valve controls the opening of the duct lumen. The proximal gland duct runs through a cuticular papilla that opens between the dorsal ovipositor valves. The secretions may serve for ovipositor valve lubrication and possibly to protect laid eggs. Observations of serial sections through the vagina exclude the presence of a spermatheca in this species. 相似文献
18.
Cell and Tissue Research - The infracerebral complex consists of: (a) two types of ependymoid infracerebral cells located on the ventral surface of the brain, adjacent to a coelomic sinus and blood... 相似文献
19.
Dr. Graham Walker 《Protoplasma》1970,71(1-2):91-109
Summary Four cell types have been identified in the digestive glands from light and electron microscope studies. The possible functions of each cell type are discussed.Thin cells are undifferentiated. Calcium cells contain spherules of calcium salts which have a characteristic ultrastructure. Different protein granules are found apically. Digestive cells are present as two distinct forms. One form is believed to be absorbing food material and digesting it intracellularly, and the other form is a secreting cell. Both forms contain green and yellow granules and histochemistry shows these granules to be distinct. Protein granules also occur apically.Excretory cells are distinguished by having a large central vacuole containing excretory granules. Histochemistry shows these granules, like the yellow granules of digestive cells, to be composed mainly of lipofuscin.It is suggested that digestive cells form excretory cells. 相似文献
20.
?Microbialites in the Permian-Triassic boundary interval in central China: Structure, age and distribution 总被引:11,自引:0,他引:11
Summary A carbonate crust, with a principally digitate structure, caps latest Permian reef complexes in east Sichuan, China. The crust
contains the conodontHindeodus parvus, confirming its age as earliest Triassic; it therefore closely postdates the end-Permian mass extinction, and is related
to associated palaeoenvironmental change. Although its branches have lobate margins, and internal structures of radial fabrics
and lobate fabrics in different specimens, an organic origin cannot be confirmed, because crust fabric is largely recrystallised.
Therefore we apply the term ?microbialite to reflect uncertainty of its nature. The crust is co-eval (within theparvus Zone) with confirmed microbial biostromes and mounds in Guizhou Province, south of Sichuan. The sum of evidence, assembled
by workers in several sites worldwide, indicates a sea-level rise occurred in the boundary interval, and this is corroborated
by facies of the Sichuan crust. Abrupt appearance and disappearance of the crust, formed by precipitated carbonates, in east
Sichuan, represents short-lived unusual post-extinction marine conditions which were switched abruptly on, then off. Microbial
deposits overlying the P/T boundary in other locations in the Tethys Ocean (Iran and Japan) support the view that the unusual
oceanic conditions had at least a regional distribution. Because the crust abruptly terminates, and is not succeeded by fossil-rich
deposits, application of the disaster biota concept is inappropriate; an environmentally-driven control on carbonate precipitation
is better supported by the evidence, whether or not it was biotically-mediated. 相似文献