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1.
The colonial morphology of three strains of cultivable, nonpathogenic treponemes including a human oral treponeme was examined by light and electron microscopy. Treponema phagedenis strains Kazan and Reiter produced large white colonies on the surface of solid media composed of sterility test broth, 0.9 to 3.1% agar, rifampin, and 12.5% rabbit or horse serum. A human oral treponeme, strain G7201, grew as diffused white zones on 0.9 to 3.1% agar plates. Under the cultural conditions employed agar concentrations slightly affected the time of appearance of colonies of the three strains of treponemes. When the colonies of these three strains were viewed by scanning electron microscopy, differences in their colonial morphology were observed. The 11-day-old colonies of human oral strain G7201 were very small, 5 to 15 μm in diameter, and had a slight irregular border. Kazan treponemes developed circular, entire and low convex colonies. Scanning and transmission electron microscopy revealed that the colonies of Reiter treponemes contained spherical forms almost up to 5 μm in diameter, each consisting of an outer membrane and a treponemal main body. They were very similar to the spherical bodies produced by strain G7201 in sucrose-containing broth. 相似文献
2.
Toshihiko Umemoto Isamu Namikawa Zensaku Yoshii Hisanori Konishi 《Microbiology and immunology》1982,26(3):191-198
The osmium-dimethyl sulfoxide-osmium method for clear visualization of intracellular structure was used to observe the detailed inner structure of the spherical bodies produced in vitro by a human oral treponeme. Scanning electron microscopy of the cracked spherical body revealed no morphological differences between the outer and inner surfaces of the spherical body membrane, and that multiple folded or somewhat linear main bodies adhere closely to the inner surface. In addition, axial flagella partially free from the main bodies spread widely within the body to make a network, and a number of blebs ranging from approximately 1 μm to 0.2 μm in diameter were located near the terminal or subterminal areas of the main bodies. The origin of the blebs and the mechanism of spherical body formation are discussed. 相似文献
3.
In cells of cyanobacterium Anabaena variabilis grown under ordinaryair (low-CO2 cells), the transport of both CO2 and HCO3was significantly enhanced by Na+. This effect was pronouncedas the external pH increased. When low-CO2 cells were treatedwith an inhibitor of carbonic anhydrase (CA), only CO2 transportbut not HCO3 transport, was inhibited. The initial rateof photosynthetic carbon fixation as a function of the concentrationof internal inorganic carbon (IC) was practically the same irrespectiveof whether CO2 or HCO3 was externally supplied. Theseresults suggest that IC is actively transported through theplasma membrane in a form of HCO3 probably by some transporterand that the transmembrane Na+ gradient is involved in thisIC transport system. Free CO2 may be hydrated by CA to HCO3and then transported to the cells by this transporter. On the other hand, CO2 is actively taken up by cells grown withair containing 5% CO2 (high-CO2 cells) though the enhancingeffect of Na+ was much smaller in high- CO2 cells than in low-CO2cells. The initial rate of fixation as a function of internal IC concentrationindicated that the rate of the carboxylation reaction of accumulatedIC is higher in I0W-CO2 cells than in high-CO2 cells. The studieswith ethoxyzolamide indicated that even in low-CO2 cells, CAdoes not function inside Anabaena cells. These results suggestthat inside the low-CO2 cells of Anabaena, some mediator(s)facilitates the transport of IC to RuBPCase. (Received January 23, 1987; Accepted April 24, 1987) 相似文献
4.
Inorganic carbon transport during photosynthesis of cyanobacteriumAnabaena variabilis grown under ordinary air was investigatedby supplying 14CO2 or H14CO3 solution to three differentstrains. Both CO2 and HCO3 were accumulated within thealgal cells. In the cell suspension from which dissolved inorganiccarbon had been depleted by pre-illumination, CO2 was transportedand accumulated faster than HCO3. When the concentrationof HCO3 injected into the cell suspension of A. variabilisM3 was 25 times as high as that of CO2 (the expected ratio atequilibrium at pH 7.8), the initial rates of fixation of bothinorganic carbon species were practically the same. On the otherhand, when 14CO2 or H14CO3 was added under steady statephotosynthetic conditions, both carbon species were transportedat similar rates. The ratio of fixed to transported carbon measuredafter the initial 5 s was only 2327% regardless of thecarbon species supplied. This percentage is much lower thanthat reported for Chlorella cells.
1 To whom reprint requests should be addressed (Received June 30, 1986; Accepted December 16, 1986) 相似文献
5.
Hiroaki Nobuhara Keisuke Kuida Makoto Furutani Toshihiko Shiroishi Kazuo Moriwaki Yusuke Yanagi Tomio Tada 《Immunogenetics》1989,30(6):405-413
Southern blots of genomic DNA from 23 strains of laboratory mice and 19 individual wild mice were examined for restriction
fragment length polymorphisms in their loci encoding the T-cell receptors (Tcr): the constant regions of the α, β, and γ chains
(C
α,C
β, andC
γ) and a variable region family of the β chain (V
β8). Only a few polymorphisms were observed for each locus in the laboratory mice after using three restriction enzymes,Bam HI,Eco RI, andHind III. All the laboratory mice examined fall into one of two types for theC
α,C
β andV
β8 loci and one of three types for theC
γ. These types are found in some of the wild mice studied, indicating that they were already present in the founder mice of
laboratory mouse strains. In contrast, theTcr genes are highly polymorphic among wild mice. Analysis of the polymorphisms in these loci suggests that laboratory mice have
inherited their genes not only fromMus musculus domesticus, but also from other subspecies, and much more than previously believed from Asian subspecies. 相似文献
6.
Fumiyasu Fukumori Naomi Takeuchi Toshihiko Hagiwara Katumi Ito Naohisa Kochibe Akira Kobata Yoshiho Nagata 《FEBS letters》1989,250(2)
Aleuria aurantia lectin (AAL) shows sugar-binding specificity for L-fucose. A λgt11 expression library was constructed from A. aurantia poly(A) RNA and screened with a polyclonal antiserum directed against AAL. An immunopositive clone carrying 1.3-kb EcoRI fragment was obtained. The fragment encoded AAL, but lacked a nucleotide sequence corresponding to the two amino-terminal amino acids. The 5′-terminal part of the fragment was replaced with a chemically synthesized DNA fragment and inserted into an expression vector to yield a plasmid pKA-1. Escherichia coli carrying pKA-1 expressed functional AAL and the recombinant AAL showed the same immunological properties as those of natural AAL. 相似文献
7.
Abstract The receptors involved in the recognition of Salmonella typhimurium and S. typhi by murine macrophages were identified, and their relevance to phagosome-lysosome fusion was also investigated. Phagocytosis of S. typhimurium by murine macrophages was dependent on the opsonization with normal fresh serum, although the opsonin had no triggering activity in phagosome-lysosome fusion. In contrast, the opsonization of S. typhi with normal fresh serum efficiently triggered both phagocytosis and following phagosome-lysosome fusion. Anti-murine CR1 antibody suppressed phagocytosis of S. typhimurium by 36%, whereas anti-CR3 antibody, mannan, and advanced glycosylation endproducts (AGE)-BSA all failed to prevent phagocytosis of S. typhimurium , suggesting that CR1 may only contribute to the recognition of S. typhimurium and may possibly play a minor role. Other receptors involved may also influence the outcome phagocytosis in terms of phagosome-lysosome fusion. In the case of S. typhi , only anti-CR3 antibody significantly inhibited not only phagocytosis of S. typhi but also following phagosome-lysosome fusion. Treatment with K76COONa, an inhibitor of C3bINA (I factor), resulted in a marked inhibition of phagosomelysosome fusion in S. typhi -infected macrophages, although no significant inhibition was observed on phagocytosis of S. typhi . These results suggest that S. typhimurium and S. typhi may be recognized at least in part by CR1 and CR3, respectively, and that the recognition by CR3 but not CR1 is functionally associated with subsequent phagosomelysosome fusion in murine macrophages. 相似文献
8.
Accumulation of collagen III at the cleft points of developing mouse submandibular epithelium 总被引:7,自引:0,他引:7
Y Nakanishi H Nogawa Y Hashimoto J Kishi T Hayakawa 《Development (Cambridge, England)》1988,104(1):51-59
The distribution of collagens I, III, IV and V was studied by immunoperoxidase staining of early developing mouse submandibular glands. Collagen I was always present in the extracellular matrices of the mesenchyme and at the epithelial-mesenchymal interfaces of the 12-day gland with no clefts and of the 13-day gland with a few definite clefts. Collagen III was found in a similar fashion to that of collagen I in the mesenchyme, but the distribution at the epithelial-mesenchymal interfaces was very different. In the mid 12-day gland with a round lobule, collagen III was distributed at every slightly indented site of basal epithelial surfaces. At the late 12-day stage, a few initial signs of cleft appeared on the surface, at which accumulation of collagen III became evident. Intense immunoreaction of collagen III in the early 13-day gland was seen at the bottom of every narrow cleft. No specific accumulation of collagens IV and V was observed in clefts of the late 12-day and early 13-day glands. Staining of collagen III in the 12-day gland cultured for 10 h in the presence of bovine dental pulp collagenase inhibitor, which has been shown to stimulate cleft initiation, was very prominent at the bottom of every narrow cleft. These observations suggest that collagen III works as a key substance for either in vitro or in vivo cleft initiation of the mouse embryonic submandibular epithelium. 相似文献
9.
The role of interstitial collagens in cleft formation of mouse embryonic submandibular gland during initial branching 总被引:8,自引:0,他引:8
Y Fukuda Y Masuda J Kishi Y Hashimoto T Hayakawa H Nogawa Y Nakanishi 《Development (Cambridge, England)》1988,103(2):259-267
An interstitial collagenase was purified from the explant medium of bovine dental pulp and was shown to degrade collagens I and III but not IV and V. The enzyme halted cleft initiation in the epithelium of 12-day mouse embryonic submandibular glands in vitro, indicating the active involvement of interstitial collagens in the branching morphogenesis. Transmission electron microscopic observation of the intact 12-day gland without any clefts showed the scattered localization of a few collagen fibrils at the epithelial-mesenchymal interface of the bulb and also revealed the presence of numerous microfibrils around the stalk. Collagen bundles were regularly seen close to the wavy basal lamina at the bottom of clefts of the intact 13-day gland and 12-day gland cultured for 17 h under normal conditions. Mesenchymal cells were found in the clefts together with the frequent localization of peripheral nerve fibres and capillary endothelial cells. The collagen bundles were more often observed in the 12-day gland cultured in the presence of bovine dental pulp collagenase inhibitor, which had been shown to enhance cleft formation. In contrast, collagen fibrils were rarely found at the epithelial-mesenchymal interface of the 12-day gland cultured in the presence of Clostridial or bovine dental pulp collagenase. The findings indicated that the formation of interstitial collagen bundles is essential to form clefts in the epithelium both in vivo and in vitro. 相似文献
10.
When chromosome preparations made by the conventional air-drying method were processed with the OsO4/TCH technique and examined by scanning electron microscopy (SEM), spiral structures in chromatids, which have been frequently observed to be present by light microscopy, were found to be composed of 30 nm fibres. In some portions these fibres appeared to be arranged in coils to form thicker fibres. When chromosome preparations were processed for SEM without air drying, chromosomes appeared to consist of fairly homogeneous thick fibrous structures measuring about 200 nm in diameter. In relatively condensed chromosomes, these 200 nm fibres appeared to be arranged perpendicular to the long axis of the chromatid. These findings suggest that chromatid spiral structures represent a regularly loosened state of the compactly spiralized 200 nm fibres which in turn consist of spiralized 30 nm fibres. 相似文献