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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.
Interleukin (IL)-6, a cytokine featuring redundancy and pleiotropic activity, contributes to host defense against acute environmental stress, while dysregulated persistent IL-6 production has been demonstrated to play a pathological role in various autoimmune and chronic inflammatory diseases. Targeting IL-6 is thus a rational approach to the treatment of these diseases. Indeed, clinical trials of tocilizumab, a humanized anti-IL-6 receptor antibody have verified its efficacy and tolerable safety for patients with rheumatoid arthritis, Castleman''s disease and systemic juvenile idiopathic arthritis, resulting in approval of this innovative biologic for treatment of these diseases. Moreover, a considerable number of case reports and pilot studies of off-label use of tocilizumab point to the beneficial effects of tocilizumab for a variety of other phenotypically different autoimmune and chronic inflammatory diseases. Elucidation of the source of IL-6 and of mechanisms through which IL-6 production is dysregulated can thus be expected to lead to clarification of the pathogenesis of various diseases. 相似文献
4.
S Kishimoto T Takahama H Mizumachi 《Journal of immunology (Baltimore, Md. : 1950)》1976,116(2):294-300
An in vitro anti-TNP response of the spleen cells from aged C57BL/6J mice showed approximately 4-fold less PFC than did that from young adult mice. Anti-theta serum-treated young spleen cells gave an anti-TNP response that was definitely greater than the response of the anti-theta serum-treated aged spleen cells in the presence of the exogenous activated thymus cells as helper cells. These results suggest that the deficits in B cells may be partly responsible for the imparied anti-TNP response of the aged spleen cells. To examine further the capacity of stem cells in the bone marrow to generate B cells responsible for anti-TNP response in the spleen, we injected i.v. 1.5 to 2.0 times 10(7) bone marrow cells from young or aged mice into lethally irradiated syngeneic recipients that had previously been thymectomized. Four to 6 weeks later, 10(7) spleen cells from the two groups of these recipient mice were immunized with TNP-SRBC in the presence of the exogenous activated thymus cells and assayed for anti-TNP PFC. The response of the aged marrow-derived B cells was approximately one-half of that of the young marrow-derived B cells.The avidity for TNP determinant of the antibodies produced by the PFC was determined by the plaque-inhibition technique. The avidity of the antibodies produced by the aged mice was approximately 33 times lower than that by the young mice. Anti-TNP response of the young spleen cells were markedly enhanced by the addition of LPS to the cultures, whereas no or little enhancement of the response was induced in the aged spleen cells even in the presence of high concentration of LPS. In contrast, DNA synthesis of both the young and aged spleen cells was comparably stimulated by 1 mug/ml and 10 mug/ml of LPS, however, it was rather less in the aged spleen cells at a concentration of 100 mug/ml. Mechanisms responsible for the changes in avidity and responsiveness to LPS with aging are discussed. 相似文献
5.
H. Takahashi K. Takita T. Kishimoto T. Mitsui H. Hori 《Journal of Phytopathology》2002,150(10):529-535
Phenylalanine ammonia‐lyase (PAL, EC 4.3.1.5) activity in clubroot disease‐resistant turnip calli was transiently increased by 20 h after the inoculation with Plasmodiophora brassicae spores. The magnitude of the increase in PAL activity was four to six times higher than constitutive PAL activity. There was no transient increase in PAL activity in susceptible calli. Preincubation of calli in Ca2+‐free medium or the removal of Ca2+ from cell surfaces by ethylene glycol bis(2‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid‐chelation, completely inhibited induced PAL activity. The influx of exogenous Ca2+ into cells appears necessary for this pathogen induced PAL activity. Verapamil and the calmodulin inhibitor W7 almost completely inhibited induced PAL activity at 1 and 0.1 mm , respectively. Neomycin, ruthenium red and (1‐(6‐[(17β‐3‐Methoxyestra‐1,3,5‐(10)‐trien‐17‐yl)amino]hexyl)‐1H‐pyrrole‐2,5‐dione) did not inhibit induced PAL activity. Thus, verapamil and N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulphonamide hydrochloride‐sensitive Ca2+‐mediated signalling process appear necessary for P. brassicae induced PAL activity. As the protein synthesis inhibitor cycloheximide (CHX) blocked the induced increasing PAL activity, de novo synthesis of PAL appears to be required for turnip cell defence reactions against P. brassicae. 相似文献
6.
The degree of methylation at the c-myc proto-oncogene was found to change in human lymphoproliferative diseases, when examined using a methylation-sensitive restriction enzyme. In peripheral blood mononuclear cells (PBMC) c-myc DNA showed hypomethylation in human lymphoproliferative diseases, in comparison to normal subjects matched in age and sex. In cases of chronic lymphocytic leukemia (CLL), the change was amplified in the crisis. When the DNA was examined at the actin gene, no significant change was observed. The results suggest that the change in c-myc proto-oncogene methylation might become an important clue in understanding the relationship between levels of gene expression and methylation in human lymphoproliferative diseases. 相似文献
7.
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
8.
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
9.
Structure and expression of human B cell stimulatory factor-2 (BSF-2/IL-6) gene. 总被引:55,自引:5,他引:50 下载免费PDF全文
K Yasukawa T Hirano Y Watanabe K Muratani T Matsuda S Nakai T Kishimoto 《The EMBO journal》1987,6(10):2939-2945
The chromosomal DNA segment of human B cell stimulatory factor-2 (BSF-2/IL-6) was isolated and characterized by nucleotide sequence analysis. The human BSF-2/IL-6 gene consists of five exons and four introns and its organization shows a distinctive similarity to granulocyte colony-stimulating factor gene. The two genes have the same number of exons and introns and the size of each exon is strikingly similar. The BSF-2/IL-6 mRNA was found to be constitutively expressed in a human T cell leukemia virus-1 transformed T cell line, TCL-Na1, a bladder cell carcinoma line, T24, and an amnion derived cell line, FL. The BSF-2/IL-6 mRNA was also found to be inducible with interleukin-1 beta in an astrocytoma line, U373 and a glioblastoma line, SK-MG-4. S1 mapping and primer extension analyses showed the presence of multiple initiation sites and the preferential utilization of a different initiation site for each individual tissue tested. 相似文献
10.
Alpha-hydroxylation of lignoceroyl-CoA by a cyanide-sensitive oxygenase in rat brain microsomes 总被引:1,自引:0,他引:1
The enzymatic mechanism of alpha-hydroxylation of lignoceroyl-CoA, an intermediate in the synthesis of hydroxyceramide, was studied. In the presence of NADPH, sphingosine and microsomes from 20-day-old rat brain, 14C from [1-14C]lignoceroyl-CoA was incorporated into hydroxyceramide. Activity was linear with time (up to 40 min) and with protein (up to 0.8 mg). The apparent Km for lignoceroyl-CoA was about 10 microM. NADPH was a more efficient electron donor than NADH. Oxygen was required for activity, which increased linearly up to 20% O2. In 5 and 10% oxygen, the reaction was inhibited by 0.1 mM cyanide and by electron transfer chain inhibitors, cytochrome c, ferricyanide, menadione, and p-chloromercuriphenyl sulphonate; CO and SKF-525A had no effect. Moreover none of the inhibitors affected the formation of hydroxyceramide. Lignoceroyl-CoA alpha-hydroxylase appears to be an oxygenase requiring NADPH and oxygen, which involves cyanide-sensitive enzyme. 相似文献