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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 423-443 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The respiratory organs of Amphipnous cuchia comprise a pair of aicsacs, vestigial gill filaments borne on second gill arch and vascular folds of the third gill arch. The volume of each air-sac, its surface area and its reltionship with the body weight of the fish have been determined. The air-sac is lined by a respiratory mucosa which is composed of vascular and non-vascular areas. Each vascular area, called here the ‘respiratory islet,’ studded with hundreds of vascular rosettes, which are formed of collagenous material and supported by endothelial cells. Pilaster cells are absent. The ‘islets’ are covered over by a single layer of squamous type of epithelial cells.The non-vascular areas (lanes') are the stratified part of the respiratory epithelium and contain a large number of mucous glands which secrete mainly acid mucopolysaccharides.The vascularisation of the gills have been studied by India ink injection methods. The secondary gill lamellae are absent, their place being taken up by coiled vascular loops.A quantitative estimation of haemoglobin in blood of ‘cuchia’ and other air- and water-breathing fishes have been made by colorimetric method and the results have been discussed in relation to their habit and habitats. The cranial muscles which are involved in respiration of ‘cuchia’ and the mechanics of muscle action in breathing have been described.
    Additional Material: 11 Ill.
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  • 2
    ISSN: 1040-452X
    Keywords: Embryo ; Incision ; Zona pellucida ; Trophoblast ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Experiment I was designed to determine if cell-free synchronous uterine flushings contain an embryotoxic substance that is normally screened by the intact zona pellucida. Sixty 4-cell embryos were allocated to three treatment groups: (1) control embryos (n = 20) were cultured in Modified Kreb's Ringer Bicarbonate medium + 10% bovine calf serum (mKRB-BCS), (2) UF embryos (n = 20) were cultured in 80% mKRB-BCS + 20% sterile dialyzed uterine flushings (UF), (3) MicroUF embryos (n = 20) received a microsurgical incision in the zona pellucida and were cultured in 80% mKRB-BCS + 20% UF. Following 72 h in culture at 37°C under a 90% N2, 5% CO2, and 5% O2 atmosphere, the number of nuclei/embryo and the incidence of protrusion of the trophoblast through the zona pellucida (PTZ) were recorded. Addition of UF had no effect on embryo development. A greater (P 〉 .005) proportion of MicroUF embryos exhibited PTZ as compared to UF and control embryos. Experiment II was devised to further characterize the occurrence of PTZ in Micro porcine embryos. Thirty-three 4- to 10-cell embryos and 14 morulae were distributed across two treatments: (1) control embryos (n = 16 and 6, respectively) were cultured as described in Experiment I; and (2) micro embryos were treated similarly to MicroUF embryos in Experiment I but were cultured in mKRB-BCS only. At the onset of PTZ, embryos were immediately fixed and examined. The proportion of embryos exhibiting PTZ was greater (P 〈 .007) for Micro versus control embryos. Both the mean time to PTZ and the number of nuclei present were greater for blastocysts cultured from control as opposed to Micro morulae (P 〈 .0001 and P 〈 .0002, respectively). These results indicate that (a) cell-free synchronous uterine flushings are not detrimental to embryos with incised zonae and (b) microsurgery increases the incidence of and reduces the time to protrusion of the embryo through the zona pellucida in cultured embryos.
    Additional Material: 5 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 202 (1982), S. 15-22 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The placental labyrinth of the three-toed sloth (Bradypus tridactylus) was examined by electron microscopy. The material available was from two fetuses of 55 mm and 150 mm crown-rump length (CRL). The placenta of the younger specimen was a transition form between the syndesmochorial type and the endotheliochorial type. The interhemal membrane of the 55 mm CRL specimen consisted of the following components: (1) hypertrophied maternal endothelial cells surrounding the maternal vessels; (2) a small amount of extracellular material and spindle-shaped cells, both presumed to be of maternal origin; (3) a layer of syncytial trophoblast that had an unusual, reticulated or sponge-like appearance; and (4) the fetal capillary endothelium. In addition, the fetal connective tissue contained hypertrophied mesenchymal cells that were characterized by abundant granular endoplasmic reticulum. The placenta of the 150 mm CRL fetus was poorly preserved, but it was possible to determine that the placenta was of the endotheliochorial type. There was a close apposition of maternal endothelium and trophoblast. The results confirmed virtually all of the light microscopic observations of Wislocki (1927; 1928b). The ultrastructure of the sloth interhemal membrane is compared to that of other endotheliochorial placentas, particularly that of the shrew, with which it shows many cytological similarities.
    Additional Material: 7 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Philadelphia : Wiley-Blackwell
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 9 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Philadelphia : Wiley-Blackwell
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 6 Ill.
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  • 6
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Epithelial cells from the lens equator differentiate into elongated fiber cells. In the final steps of differentiation, the chromatin appears quite condensed and chromatin breakdown into nucleosmes occurs. DNA breaks due to an endodeoxyribonuclease activity corresponding to at least two polypeptides of 30 and 40 kDa have been identified. To identify the nature and the developmental appearance of initial breaks, nick translation reaction was followed both biochemically and in situ in fiber and epithelial cells from chick embryonic lenses. There is no accumulation of single-strand breaks (SSB) with 3'OH ends in lens fiber cells during embryonic development. Such damage can be increased in these cells by treatment with DNAase I indicating the absence of an inhibitor of the nick translation reaction in fiber cells. However, there are indications of the presence of DNA breaks with blocked termini when the phosphatase activity of nuclease P1 is used. The presence of breaks is also indicated by the large amounts of (ADP-ribose)n found in lens fibers particularly at 11 days of embryonic development (E11) as ADP-ribosyl transferase binds to and is activated by DNA strand breaks. Incubation of lens cells in vitro, which causes nucleosomal fragmentation only in fiber cells, produces SSB with 3'OH ends in both epithelia and fibers. Incubation for short periods, observed in experiments in situ, induces SSB first in the central fiber nuclei, which are late in differentiation. This may indicate that these SSB play a physiological role. Long incubations produce larger numbers of SSB in epithelia than fibers. The SSB in the fibers may have been converted into double-strand breaks (D SB), seen as nucleosomal fragments, and therefore no longer act as substrates for nick translation. The nuclease activity responsible for SSB production is independent of divalent cations and could be implicated in lens terminal differentiation. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 7
    ISSN: 1040-452X
    Keywords: Thawing velocity ; Freezing rate ; Glycerol concentration ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of thawing velocities ranging from 10°C/min to 1.800°C/min on the motility and acrosomal integrity of boar spermatozoa frozen at 1°C/min (suboptimal), 5°C/min, and 30°C/min (optimal) rate was studied with the sperm suspended for freezing in diluent containing 2, 4, or 6% of glycerol (v/v). The influence of thawing on sperm survival depends on the rate at which the sperm had been frozen. In semen frozen at a suboptimal rate of 1°C/min, the percentage of motile sperm (FMP) initially fell to 3.5-4.0% when the thawing rose to 200°C/ min, but, with further increases in thawing rate, increased and reached peak values (10.3-11.0% FMP) after thawing at 1,800°C/min. The percentage of sperm with normal apical ridge (NAR) also increased moderately with thawing rate, but the degree of improvement decreased as the glycerol level was increased. In semen frozen at 1°C/min, acrosomal integrity (NAR) was best maintained in 2% glycerol, reaching 22.9% NAR after thawing at 1,800°C/min. In semen frozen at the optimal rate of 30°C/min, the increases in thawing rates above 200°C/min substantially improved motility. Motility was generally higher in semen protected by 4 or 6% glycerol, with the peak values of 44 or 46% FMP, respectively, after thawing at 1,200°C/min. The proportion of sperm with NAR also increased with thawing rate, but as in the case of suboptimally frozen sperm it was influenced negatively by the glycerol concentration. The peak value 53% NAR was recorded in semen protected by 2% glycerol, frozen at 30°C/min, and thawed at 1,200°C/min. In view of the inverse relationship between FMP and NAR, selection of optimal conditions from among the interacting variables, freezing rate, glycerol concentration, and thawing rate requires compromising between maximal FMP and maximal NAR. Accordingly, we have adopted as optimal a protocol with a thawing rate of 1,200°C/min, a freezing rate of 30°C/min and concentrations of 3% glycerol. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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  • 8
    ISSN: 1040-452X
    Keywords: Phosphorylation ; Chromatin condensation ; Testis ; DNA binding proteins ; Seminiferous tubules ; Sonication-resistant nuclei ; mP1 ; Pre-mP2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mouse and rat seminiferous tubule fragment cultures were used to examine synthesis and processing of mammalian protamines and transition proteins. The tubule fragments were incubated with [3H]-arginine, [3H]-histidine, [35S]-cysteine, or [32P]-PO4, and radiolabeled proteins were analyzed by acid/urea polyacrylamide gel electrophoresis and fluorography or autoradiography. Newly synthesized protamines were recovered from sonication-resistant nuclei (SRN) and could not be detected in cytoplasmic fractions, indicating that protamines are deposited into nuclei immediately after synthesis. Newly synthesized mouse protamine 1 (mP1) and the precursor to mouse protamine 2 (pre-mP2) migrated more slowly during electrophoresis than their predominant testicular forms, identified by staining with Coomassie blue R-250. Within 1 hour of synthesis, the electrophoretic mobilities of mP1 and pre-mP2 increased to match those of their predominant forms. These changes are consistent with initial charge-neutralizing modifications of the newly synthesized protamines, followed by removal of at least some of the modifying ligands, to unmask protamine basicity. Steady-state phosphorylation rates were high for rat protamine 1 (rP1) and were independent of phosphate content; both rP1 molecules of low and high phosphate content were rapidly phosphorylated. Pre-mP2-3, a major processing intermediate derived by proteolysis of pre-mP2, was also rapidly phosphorylated. Like the protamines, transition protein 2 (TP2) was rapidly phosphorylated and increased in electrophoretic mobility soon after synthesis. In contrast, transition protein 1 (TP1) was not phosphorylated and did not exhibit multiple electrophoretic forms. © 1994 Wiley-Liss, Inc.
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  • 9
    ISSN: 0730-2312
    Keywords: rat protein kinase C ; recombinant baculovirus ; antisera ; phorbol ester ; isoenzymes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Expression of rat protein kinase C-δ (PKC-δ ) and PKC-ξ in insect cells using recombinant baculovirus resulted in the production of proteins with a molecular size of approximately 76 kD and 78 kD, respectively, as determined by immunoblotting with subtype-specific antisera. Although the PKC-ξ cDNA encoded for 592 amino acids, a 76 kD protein was also generated by in vitro transcription/translation. Extracts of cells expressing PKC-δ were able to bind phorbol ester to levels comparable to extracts of cells expressing PKC-α. No phorbol ester binding was, however, detected in insect cell extracts expressing PKC-ξ. However, similar levels of protein kinase activity were detected in lysates of cells expressing PKC-δ or PKC-ξ when protamine sulfate was used as exogenous substrate. Compared to protamine sulfate, both, myelin basic protein (MBP) or histone, were poor substrates for PKC-δ and PKC-ξ. In contrast to PKC-ξ, the PKC-δ enzyme activity phosphorylated MBP or histone in a phosphatidylserine-(PS)/diacylglycerol(DG)-dependent manner, albeit not to the same extent as PKC-α. Lack of stimulation of the enzyme activity of PKC-ξ by PS/DG, was confirmed by endogenous phosphorylation of insect cell proteins by PKC-ξ, whereas several insect cell proteins were phosphorylated by PKC-δ in a PS/DG-dependent manner, including a protein of 78 kD.Our data demonstrate that the 76 kD PKC-ξ, in contrast to PKC-δ, is unable to bind phorbol esters and displays a protein kinase activity that is independent of PS of PS/DG. In addition, staurosporine was about 2-4 order of magnitudes less effective in inhibiting the protein kinase activities of PKC-δ and PKC-δ when compared to PKC-ξ.
    Additional Material: 7 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 145 (1976), S. 395-408 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The proliferative kinetics of the intraepithelial lymphocytes (IL) of the mouse intestine have been evaluated. By inducing mitotic arrest it was found that large IL  -  constituting about 50% of the IL  -  showed a mitotic rate of 2.3. Autoradiographic results obtained after two different schedules of 3H-thymidine injections showed that 30% of the large IL were in DNA synthesis, and that the large IL were renewed at a rate comparable to that of blast cells from Peyer's patches, mesenteric lymph nodes and thoracic duct lymph. The small IL were renewed very rapidly compared to small lymphocytes of peripheral lymphoid tissues, although small lymphocytes with lifespans of several weeks were also present in the epithelial sheet. By the use of intestinal perfusion, in vivo, it was estimated that the loss of lymphocytes from intestinal villi into the lumen of the gut was negligible, and it is concluded that the most probable kinetic model for the majority of IL is: B and T lymphoblasts invade the epithelium and undergo mitosis. B lymphoblasts give rise predominantly to plasma cells, and T lymphoblasts give rise to small lymphocytes  -  probably long-lived  -  which reenter the circulation.
    Additional Material: 9 Ill.
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