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  • 1
    Electronic Resource
    Electronic Resource
    New stereospecific approach to steroid side chains: conversion of dehydroepiandrosterone to cholesterol, isocholesterol, and their 15.beta.-hydroxy derivatives (1981)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 103 (1981), S. 2907-2909 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00400a089
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  • 2
    Electronic Resource
    Electronic Resource
    Seasonal variations in the production of the egg-jelly macromolecule, a fucose sulphate glycoconjugate, by the accessory cells in the ovary of the sea urchin Hemicentrotus pulcherrimus (1994)
    Springer
    Development genes and evolution 203 (1994), S. 402-410 
    Details
    ISSN: 1432-041X
    Keywords: Sea urchin ; Egg jelly ; Ovary ; Development ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the sea urchin Hemicentrotus pulcherrimus, the egg-jelly macromolecule, a fucose sulphate glycoconjugate (FSG) that induces the acrosome reaction in spermatozoa, originates from the accessory cells in the ovary. In the present study we examined the seasonal variations in the distribution of FSG in the ovary by immunocytochemistry with a polyclonal antibody. An enzyme-linked immunosorbent assay indicated that FSG was present in supernatants of extracts of ovaries throughout the development of the ovary. However, the immunohistochemical study showed that there are marked seasonal changes in the distribution of FSG in ovaries. The polyclonal antibody reacted strongly with globules of accessory cells before the beginning of the breeding season (August to December). During the breeding season (February to April), the immunohistochemical reaction was found on the surface of oocytes but was weak in the accessory cells. At the ultrastructural level, the antibody reacted with globules of variable density in accessory cells. Intense immunolabelling was observed in the vacuole-like structures of the globules. Sometimes, products of the specific immunocytochemical reaction were found in the Golgi apparatus in these globules. Quantitative examination indicated that FSG was actively produced by the accessory cells from the late non-breeding season to the pre-breeding season. These results suggest that there are marked seasonal variations in the production of FSG by the accessory cells in the sea urchin ovary. These findings also provide new evidence that accessory cells exhibit dynamic changes during the reproductive process in the sea urchin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188689
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  • 3
    Electronic Resource
    Electronic Resource
    The egg-jelly macromolecule, a fucose sulphate glycoconjugate, originates from the accessory cells of the ovary in the sea urchin Hemicentrotus pulcherrimus (1992)
    Springer
    Development genes and evolution 201 (1992), S. 179-189 
    Details
    ISSN: 1432-041X
    Keywords: Sea urchin ; Jelly coat ; Accessory cell ; Oogenesis ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The immunocytochemical localization of the egg-jelly macromolecule, a fucose sulphate glycoconjugate (FSG) that induces the acrosome reaction in spermatozoa, was investigated in ovaries of the sea urchin Hemicentrotus pulcherrimus by use of a polyclonal antibody. The polyclonal antibody reacted with the accessory cells and oocytes in the ovarian lumen. In the accessory cells, evidence of an intense immunohistochemical reaction was observed in many globules of variable density. Products of the specific immunohistochemical reaction were frequently observed in the surface region of oocytes, at a distance from the ovarian wall. At the ultrastructural level, the polyclonal antibody was found to react with the material present in the vacuole-like structures of the globules in the accessory cells. Many gold particles, demonstrating specific immunolabelling, were associated with well-developed microvilli on the vitellogenic oocytes. In the mature oocytes, intense labelling was observed in the jelly coat but not in the vitelline coat. By contrast, oogonia and early oocytes were barely labelled. Quantitative data indicated that the extent of immunolabellings in the surface region of oocytes was very high in the vitellogenic and mature oocytes. In all cases, neither the oocyte cytoplasm nor the subcellular organelles were labelled. These results suggest that FSG is produced by the accessory cells and is deposited initially on the surface of vitellogenic oocytes for the formation of jelly. These findings may provide a new insight into the role of the accessory cells in the reproductive process of the sea urchin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00188717
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of Fatigue Crack Propagation in the Shape Memory Alloy Fiber Reinforced Smart Composite (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 334-335 (Mar. 2007), p. 1093-1096 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper, the TiNi fiber reinforced / Polycarbonate(PC) composite material isdeveloped, and its properties is studied. Conducting fatigue experiments, shape memory effect of thematerial for preventing fatigue crack growth are investigated. The fatigue behavior and crackpropagation are observed under increasing temperature with a SEM servo-pulser, which is a fatiguetesting instrument with scanning electron microscope. As the results, the effectiveness of fatigueresistance is confirmed. The shape memory effect and expansion behavior of the matrix caused byincreasing temperature create the effect of the fatigue crack propagation control. It is verified that thecontrolling of fatigue crack growth is attributed to the compressive stress field in the matrix which iscaused by shrinkage of the TiNi fibers above austenitic finishing temperature (Af)
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/53/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.334-335.1093.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    IcsB, secreted via the type III secretion system, is chaperoned by IpgA and required at the post-invasion stage of Shigella pathogenicity (2003)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 48 (2003), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Shigella deliver a subset of effector proteins such as IpaA, IpaB and IpaC via the type III secretion system (TTSS) into host cells during the infection of colonic epithelial cells. Many bacterial effectors including some from Shigella require specific chaperones for protection from degradation and targeting to the TTSS. In this study, we have investigated the role of the icsB gene located upstream of the ipaBCDA operon in Shigella infection because the role of IcsB as a virulence factor remains unknown. Here, we found that the IcsB protein is secreted via the TTSS of Shigella in vitro and in vivo. We show that IpgA protein encoded by ipgA, the gene immediately downstream of icsB, serves as the chaperone required for the stabilization and secretion of IcsB. We have shown that IcsB binds to IpgA in bacterial cytosol and the binding site is in the middle of the IcsB protein. Intriguingly, although its significance in Shigella pathogenicity is as yet unclear, the icsB gene can be read-through into the ipgA gene to create a translational fusion protein. Furthermore, the contribution of IcsB to the pathogenicity of Shigella was demonstrated by plaque-forming assay and the Sereny test. The ability of the icsB mutant to form plaques was greatly reduced compared with that of the wild type in MDCK cell monolayers. Furthermore, when guinea pig eyes were infected with a non-polar icsB mutant, the bacteria failed to provoke keratoconjunctivitis. These results suggest that IcsB is secreted via the TTSS, chaperoned by IpgA, and required at the post-invasion stage of Shigella pathogenicity
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.2003.03489.x
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of Methane Concentration in the Deposition Process on the Crystal Structure and the Adhesive Fracture Toughness of CVD Diamond (2002)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 85 (2002), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Crystal structures of CVD diamond particles were observed in detail by transmission electron microscopy. The particles were deposited on silicon substrates under various conditions and had different levels of adhesion. An interlayer of SiC was found along the interface obtained with low methane concentration in the source gas, but it disappeared when deposited with higher methane concentrations. On the other hand, the size of crystal grains became smaller with increasing methane concentrations. From the correspondence between the structures and the adhesive toughness of these particles, it was suggested that the effect of both the SiC interlayer and the variation of grain size resulted in the complicated trend of adhesion with respect to methane concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2002.tb00063.x
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  • 7
    Electronic Resource
    Electronic Resource
    Stereospecific 1,4-additions of methyl cyanocuprate to enol phosphates of .alpha.,.beta.-epoxycyclohexanones: application to the total synthesis of (.+-.)-.alpha.-multistriatin (1981)
    s.l. : American Chemical Society
    The @journal of organic chemistry 46 (1981), S. 5379-5383 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00339a026
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  • 8
    Electronic Resource
    Electronic Resource
    Dual regulatory pathways integrating the RcsC–RcsD–RcsB signalling system control enterohaemorrhagic Escherichia coli pathogenicity (2005)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 58 (2005), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Bacterial pathogenesis is strictly regulated in response to changes in environmental conditions. A His–Asp phosphorelay system consisting of a sensor kinase and response regulator is used by Gram-positive and Gram-negative bacteria to control gene expression in response to environmental stimuli. We screened His–Asp phosphorelay systems for their effect on virulence expression in enterohaemorrhagic Escherichia coli (EHEC), and found rcsD or rcsB overexpression enhanced locus for enterocyte effacement (LEE) gene transcription and adherence to Caco-2 cells through transcriptional activation of the ler regulatory gene. An EHEC-specific regulator GrvA, encoded by ECs1274, was required for ler transcription activation by RcsB. Furthermore, GrvA activated ler transcription in E. coli K12. Stimulation of the RcsDCB regulatory system by RcsF overexpression slightly increased EspB expression in the wild type but not the ECs1274 mutant. However, EspB expression in an rcsB deletion mutant increased compared with wild type, suggesting that RcsB negatively regulates LEE gene expression and that active RcsB protein is present under normal growth conditions. Deletion of pchA, which encodes a positive regulator for ler, abolished the effect of the rcsB deletion, suggesting that pchA mediated the negative RcsB effect. pchA transcript levels decreased when RcsB expression increased. Thus, LEE gene transcription may be regulated by RcsB through two oppositely regulated O157-specific regulators, PchA and GrvA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.2005.04828.x
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  • 9
    Electronic Resource
    Electronic Resource
    A serum-free culture system for efficient in vitro production of bovine blastocysts with improved viability after freezing and thawing (1999)
    Springer
    Cytotechnology 31 (1999), S. 123-131 
    Details
    ISSN: 1573-0778
    Keywords: bovine embryo ; cell morphology ; cell number ; cryopreservation ; in vitro culture ; serum-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The aim of this study was to evaluate whether two completely serum-free media (IVMD101 and IVD101) could improve the yield and quality of bovine blastocysts from in vitro matured and fertilized oocytes. The media were evaluated in the presence (IVMD101) or absence (IVD101) of bovine cumulus/granulosa cell (BCGC) cocultures. The proportion of embryos developing to the blastocyst stage in IVMD101 medium with BCGC cocultures (36.5%) and IVD101 medium without BCGC cocultures (37.1%) was significantly higher than in serum-supplemented medium (TCM199 + 5% calf serum) with BCGC cocultures (25.1%). Furthermore, the mean cell numbers per blastocyst on Day 7 developed in IVMD101 medium (179.5 cells) and IVD101 medium (177.1 cells) were greater than in the serum-supplemented medium (145.7 cells). The survival rates of blastocysts derived in IVMD101 medium (73.3%) and IVD101 medium (60.0%) based on hatching after 72 h of post-thaw culture were superior to that of blastocysts derived in the serum-supplemented medium (48.1%). Under microscopic observation, bovine blastocysts derived in the serum-supplemented medium showed abundant lipid droplets, largely into the trophectoderm cells. This morphological difference may partly explain the sensitivity of serum-derived embryos after freezing and thawing. In conclusion, these new serum-free culture media are useful, not only to study the mechanisms of early embryogenesis, but also for mass production of good quality embryos for embryo transfer, cloning and transgenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008044827145
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  • 10
    Electronic Resource
    Electronic Resource
    Bovine oviductal epithelial cells: their cell culture and applications in studies for reproductive biology (1997)
    Springer
    Cytotechnology 23 (1997), S. 171-183 
    Details
    ISSN: 1573-0778
    Keywords: oviductal epithelium ; embryo ; sperm ; co-culture ; secretion ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Epithelial cells of the mammalian oviduct play an important role in reproductive and developmental events that occur there. Oviductal epithelial cells from several mammalian species can be isolated and cultured in serum or serum-free medium in vitro and cell culture of bovine oviductal epithelial cells (BOEC) has been described by many investigators. Cultured BOEC show a wide variety of secretory activities and these secretory factors may influence early embryonic development or sperm function. Monolayer cultures of BOEC have been widely used for in vitro co-culture of bovine preimplantation embryos. The use of BOEC co-culture systems has improved embryonic development in nearly all the studies conducted. In addition, interaction of bovine spermatozoa with BOEC, in a similar manner to that observed for spermatozoa in vivo, induced specific changes in sperm capacitation and consequently improved the fertilizing capacity of bovine spermatozoa in vitro. Thus co-culture systems with BOEC may not only offer an excellent model for studying the mechanisms of capacitation and acrosome reaction of bovine spermatozoa but also provide a useful tool for the improvement of embryo development in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007929826186
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