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  • 1990-1994  (1.937)
  • 1905-1909  (179)
  • Life and Medical Sciences  (1.561)
  • Inorganic Chemistry  (555)
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  • 1
    Digitale Medien
    Digitale Medien
    Analysis of protein synthesis in morphologically classified bovine follicular oocytes before and after maturation in vitro (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 26 (1990), S. 222-226 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Cow ; Classification ; Cumulus oocyte complexes ; In vitro maturation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Bovine cumulus oocyte complexes (COCs) were isolated from antral ovarian follicles (4-8 mm). Immature COCs were classified into four categories, based on the homogeneity and clearness of the ooplasm and the transparency and compactness of the cumulus investment. In this study, the incorporation of TCA-precipitable 35S-methionine and the protein synthesis patterns of oocytes of these four categories were examined. Before maturation in vitro, similar incorporation rates and identical protein synthesis patterns were observed between oocytes of categories 1-3. Immature oocytes of category 4 showed reduced incorporation rates and exhibited aberrant protein synthesis patterns. After maturation in vitro, the patterns of category 4 oocytes were identical with the patterns of those in categories 1-3. The incorporation of 35S-methionine into in vitro matured oocytes was lower (P 〈 .001) in all categories.Based on these results, it is concluded that the initial classification of oocytes into four categories can be reduced to two categories.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080260305
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  • 2
    Digitale Medien
    Digitale Medien
    The effects of α-amanitin and cycloheximide on nuclear progression, protein synthesis, and phosphorylation during bovine oocyte maturation in vitro (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 249-254 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Cow ; In vitro maturation ; Inhibitors ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Bovine cumulus oocyte complexes were cultured for various periods and either denuded and orcein stained or radiolabeled with 35S-methionine or 32P-orthophosphate. Specific inhibitors were added to the culture medium to investigate mRNA and protein synthesis requirements for both nuclear and cytoplasmic changes during maturation in vitro. Inhibition of mRNA synthesis by α-amanitin during the first 2 h of culture prevented the phosphorylation of some specific proteins preceding GVBD and decreased the occurrence of GVBD from 97% to 27%. In addition, in oocytes that had undergone GVBD, only part of the changes in protein synthesis after GVBD were observed. Addition of α-amanitin after 3 h of culture had no effect on meiotic maturation. When cumulus oocyte complexes were cultured in the presence of cycloheximide, the phosphorylation of specific proteins was also blocked and only 5% of the oocytes underwent GVBD. Addition of cycloheximide after 4, 6, or 8 h of culture resulted in an increasing percentage of GVBD, but the oocytes became arrested in metaphase I. When cycloheximide was added from 12 h of culture onwards, nuclear progression to metaphase II was increasingly restored.It is concluded that after the onset of culture, both mRNA and protein synthesis are necessary for the phosphorylation of specific proteins and for GVBD. Further-more, transcription during the first hours of culture is needed for the synthesis of new proteins after GVBD.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080280306
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  • 3
    Digitale Medien
    Digitale Medien
    Protein synthesis and phosphorylation patterns of bovine oocytes maturing in vivo (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 271-275 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Cow ; Maturation ; Oocyte ; Protein phosphorylation ; Superovulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: To investigate protein synthesis and phosphorylation during bovine oocyte maturation in vivo, oocytes were collected at consecutive times after the preovulatory luteinizing hormone (LH) peak. Therefore, heifers treated for superovulation were ovariectomized between 3 and 20 h after the maximum of the LH peak. Subsequently, cumulus-enclosed oocytes, selected from nonatretic follicles 〉10 mm, were radiolabeled with 35S-methionine or 32P-orthophosphate for 3 h and individually prepared for gel electrophoresis. Changes in the protein synthesis patterns were observed coinciding with germinal vesicle breakdown (GVBD). No changes were detected during the ensuing maturation period or coinciding with the extrusion of the first polar body. In addition, the protein phosphorylation patterns exhibited striking differences around GVBD. In particular, a phosphoprotein band of 19 kDa and the two heavily phosphorylated proteins with apparent molecular weights between 50 and 60 kDa were present in patterns of oocytes in the germinal vesicle stage. The results are discussed in relation to previous data obtained during maturation in vitro.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080290309
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  • 4
    Digitale Medien
    Digitale Medien
    Parathyroid hormone-induced changes in alkaline phosphatase expression in fetal calvarial osteoblasts: Differences between rat and mouse (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 155 (1993), S. 36-43 
    Details
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: We studied the effects of parathyroid hormone (PTH) on two markers of the osteoblast phenotype: alkaline phosphatase (AP) (activity and mRNA) and cyclic adenosine monophosphate (cAMP) accumulation. Osteoblast-like cells derived from fetal rat (ROB) and mouse (MOB) calvariae were isolated by collagenase treatment. Cells were cultured in α-Minimal Essential Medium (MEM) with 2% fetal calf serum (FCS) for 4 days. In ROB and MOB bPTH(1-34) induced a fast increase (up to 5 minutes) in cAMP accumulation. When equal amounts of cells were seeded, the cAMP accumulation was higher in MOB than in ROB. No difference in basal AP activity was observed between ROB and MOB. When bPTH(1-34) was added to ROB for the last 24 or 48 hr, AP activity decreased dose dependently. However, MOB treated with bPTH(1-34) for the last 24 or 48 hours showed an increase of AP activity. Basal AP activity was positively correlated with the seeding density of ROB and MOB cultures. Basal AP activity influenced the degree of inhibition (ROB) or stimulation (MOB) after incubation with bPTH(1-34). © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jcp.1041550106
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  • 5
    Digitale Medien
    Digitale Medien
    Lung endocrine cell markers, peptides, and amines (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 236 (1993), S. 169-175 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092360120
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  • 6
    Digitale Medien
    Digitale Medien
    Influence of age on nuclear bodies and nuclear volume in pituicytes of the rat neurohypophysis (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 230 (1991), S. 319-324 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: This study has analyzed age-related changes in the nuclear organization of pituicytes of the rat. The cytological study of the cell nucleus and the quantitative analysis of nuclear bodies (NBs) were performed on ultrathin sections. Nuclear diameter, perimeter, and area were measured on semithin sections, and nuclear volume was estimated from these data. The nucleolus was mainly composed of a few large fibrillar centers with their associated dense fibrillar component, whereas the granular component tended to form large masses at the nucleolar periphery. The most frequent configuration of NBs was a globular inclusion composed of a fibrillar capsule with a core that contained a few electron-dense granules. Intranuclear glycogen was detected on rare occasions and only in old rats. The proportion of nuclear sections containing NBs increased significantly from 1.5% in 3-month-old rats to 8.6% in 18-month-old rats. A significant increase in the nuclear volume was detected in older rats with respect to the younger ones (157±69 vs. 98±43 μm3, mean ±S.D.). Our results suggest an age-related activation of nuclear metabolism in pituicytes resulting in a nuclear expansion and an increase in the frequency of appearance of NBs. This activation might be a reactive cellular event induced by the degenerative changes in neurosecretory nerve endings naturally occurring in older animals.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092300304
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  • 7
    Digitale Medien
    Digitale Medien
    An immunocytochemical study of cutaneous innervation and the distribution of neuropeptides and protein gene product 9.5 in man and commonly employed laboratory animals (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 191 (1991), S. 369-383 
    Details
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The cutaneous nerves of rat, cat, guinea pig, pig, and man were studied by immunocytochemistry to compare the staining potency of general neural markers and to investigate the density of nerves containing peptides. Antiserum to protein gene product 9.5 (PGP 9.5) stained more nerves than antisera to neurofilaments, neuronspecific enolase (NSE), and synaptophysin or histochemistry for acetylcholinesterase (AChE). Peptidergic axons showed species variation in density of distribution and were most abundant in pig and fewest in man. However, the specific peptides in nerves innervating the various structures were consistent between species. Nerve fibers immunoreactive for calcitonin gene-related peptide (CGRP) and/or vasoactive intestinal polypeptide (VIP) predominated in all the species; those immunoreactive to tachykinins (substance P and neurokinin A [NKA]) and neuropeptide tyrosine (NPY) were less abundant. Neonatal capsaicin, at the doses employed in this study, destroyed approximately 70% of CGRP- and tachykinin-immunoreactive sensory axons; whereas 6-hydroxydopamine (6-OHDA) at the doses employed resulted in a complete loss of NPY and tyrosine hydroxylase (TH) immunoreactivity without affecting VIP, CGRP, and tachykinins.Thus, this study confirms that antiserum to PGP 9.5 is the most suitable and practical marker for the demonstration of cutaneous nerves. Species differences exist in the density of peptidergic innervation, but apparently not for specific peptides. Not all sensory axons immunoreactive for CGRP and substance P/NKA are capsaicin-sensitive. However, all sympathetic TH- and NPY- immunoreactive axons are totally responsive to 6-OHDA; but no change was seen in VIP-immunoreactive axons, suggesting some demarcation of cutaneous adrenergic and cholinergic sympathetic fibers.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/aja.1001910404
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  • 8
    Digitale Medien
    Digitale Medien
    Modulation of responsiveness to cAMP stimulating agonists by phorbol ester in fetal rat osteoblasts (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 147 (1991), S. 87-92 
    Details
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: We studied the effect of activation of protein kinase C (PKC) by a phorbol ester on cAMP accumulation in fetal rat osteoblasts. Activation of PKC by phorbol 12-myristate 13-acetate (PMA) caused a potentiation of cAMP accumulation induced by parathyroid hormone (PTH), forskolin, and cholera toxin. The results suggest that the potentiating effect of PMA on PTH-induced cAMP accumulation was not due to an effect on the PTH-receptor nor to an effect on cAMP degradation, as the effect of PMA persisted in the presence of a phosphodiesterase inhibitor. Pretreatment of the cells with pertussis toxin did not prevent the action of PMA, indicating that PMA does not act via the inhibitory G-protein. PMA had a biphasic effect on prostaglandin E2 (PGE2)-induced cAMP accumulation; i.e., at concentrations ≥ 10-6 M, PMA potentiated the PGE2-induced cAMP response but PMA attenuated cAMP accumulation induced by concentrations of PGE2 ≤ 5.10-7 M. From our data we conclude that PKC can interact with a stimulated cAMP pathway in a stimulatory and inhibitory manner. Potentiation of cAMP accumulation is probably due to modification of the adenylate cyclase complex, whereas attenuation of stimulated cAMP accumulation appears to be due to an effect on a different site of the cAMP generating pathway, which may be specific to PGE2-induced cAMP accumulation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jcp.1041470112
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  • 9
    Digitale Medien
    Digitale Medien
    Amorphisation of MgO single crystal specimens prepared by ion milling for transmission electron microscopy studies (1990)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 15 (1990), S. 377-382 
    Details
    ISSN: 0741-0581
    Schlagwort(e): Vickers indentations ; Magnesium oxide ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Single crystal MgO specimens having low load Vickers indentations were thinned in an ion milling machine employing a single ion gun, and their characteristics were investigated with optical microscopy and high voltage electron microscopy (HVEM). It was found that the state of cleanliness of the specimen chamber of the ion milling machine had a very marked influence on the quality of the thinned specimens. If the specimen chamber was not well cleaned before ion milling a fresh specimen, the latter tended to show amorphisation due to the deposition on the specimen of the debris left in the chamber from the previously ion-milled specimens. Such observations were made from MgO specimens ion milled in several different types of commercial ion milling machine employing a single gun. It is proposed that to obtain good-quality ion milled TEM specimens, it is important to clean the specimen chamber thoroughly prior to milling.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1060150407
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  • 10
    Digitale Medien
    Digitale Medien
    Fimbrin localized to an insoluble cytoskeletal fraction is constitutively phosphorylated on its headpiece domain in adherent macrophages (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 223-233 
    Details
    ISSN: 0886-1544
    Schlagwort(e): actin-bundling protein ; phosphorylation ; macrophage fractions ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The actin-bundling protein fimbrin is homologous to l-plastin, a 65kD phosphoprotein expressed in leukocytes and transformed cells [de Arruda et al., J. Cell Biol. 111, 1069-1080]. Because fimbrin is present in cell adhesion sites, we studied the phosphorylation state of fimbrin and its distribution in macrophages sequentially extracted with Triton-X-100 (soluble fraction), Tween 40-deoxy-cholate (cytoskeletal fraction), and SDS (insoluble cytoskeletal fraction). The approximate distribution of fimbrin and actin among these fractions was found to be: 65% fimbrin/55% actin in the soluble fraction, 30% fimbrin/20% actin in the cytoskeletal fraction, and 5% fimbrin/25% actin in the insoluble cytoskeletal fraction. PMA did not alter this distribution. Fluorescence microscopy of acetone-extracted macrophages showed that actin is concentrated in podosomes at the substratum interface and is diffusely distributed throughout the remainder of the cell. Fimbrin colocalizes with actin in podosomes and also exhibits a punctate distribution in the cytoplasm that overlaps with actin. In Tween 40/DOC-extracted cells, podosomes remain, and fimbrin also exhibits a punctate distribution along actin filaments. Metabolic 32PO4 labeling revealed that fimbrin is constitutively phosphorylated and that phosphorylated fimbrin is concentrated in the insoluble cytoskeletal fraction. PMA increased the relative levels of fimbrin phosphorylation twofold but did not alter the pattern of fimbrin fluorescence or the distribution of phosphorylated fimbrin. Limited trypsin digestion and phosphoamino acid analysis demonstrated that phosphorylation occurs specifically on serine residues within the 10kD headpiece domain of fimbrin. Phosphorylation of the headpiece domain could regulate the actin binding and bundling properties of fimbrin, or it could regulate the interaction of fimbrin with other proteins. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cm.970250303
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