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31.
Comparison of OspA Serotypes for Borrelia burgdorferi Sensu Lato from Japan,Europe and North America
Toshiyuki Masuzawa Bettina Wilske Tetsuro Komikado Hiroyuki Suzuki Hiroki Kawabata Nanao Sato Koichi Muramatsu Nobutake Sato Emiko Isogai Hiroshi Isogai Russell C. Johnson Yasutake Yanagihara 《Microbiology and immunology》1996,40(8):539-545
Sixty-one Borrelia burgdorferi sensu lato strains from various sources (ticks, human, and wild animals) in Japan and two strains from ticks in Far Eastern Russia were classified on the basis of reactivity with 16 monoclonal antibodies (mAb) to outer surface protein A (OspA) and by DNA-DNA hybridization assay. Eleven OspA serotypes (J1 to J11) were recognized among the Japanese and the Far East Russian isolates (serotypes J1 to J9 were identified as B. garinii, serotype J10 was identified as B. afzelii, and serotype J11 corresponded to B. japonica), whereas 7 OspA serotypes for North American and European isolates previously reported (Bettina Wilske et al, J. Clin. Microbiol. 31:340-350, 1993) were not observed except for OspA serotype 2 which showed identical reactivity with OspA serotype J10. This finding provides helpful information for understanding the geographical distribution of Lyme disease borrelia and the development of vaccine and diagnostic tests. In conclusion: 1. B. burgdorferi sensu stricto has not been observed in Japan, 2. Japanese B. afzelii isolates are closely related to those from Europe, 3. B. garinii isolates from Japan are highly heterogeneous and apparently different from European B. garinii isolates. 相似文献
32.
Minamisawa Kiwamu; Ogawa Ken-Ichiro; Fukuhara Hideyuki; Koga Jinichiro 《Plant & cell physiology》1996,37(4):449-453
Indole-3-acetaldehyde (IAAId) was detected in the culture supernatantof Bradyrhizobium elkanii. Deuteriumlabelled L-tryptophan (Trp)was incorporated into IAAId and indole-3-acetic acid (IAA),suggesting that B. elkanii produces IAA via IAAId from Trp.In B. elkanii cell suspension, indole-3-pyruvic acid (IPyA)was converted to IAAId, and exogenously added IAAId was rapidlyconverted to IAA. Furthermore, the activity of indolepyruvatedecarboxylase (IPDC), which catalyzes the decarboxylation ofIPyA to produce IAAId and is a key enzyme for IPyA pathway,was detected in B. elkanii cell-free extract. The IPDC activitydepended on Mg2+ and thiamine pyrophosphate, cofactors of decarboxylation.This mounting evidence strongly suggests that IAA synthesisoccurs via IPyA pathway (Trp IPyA p IAAId IAA) in B. elkanii. (Received December 11, 1995; Accepted March 4, 1996) 相似文献
33.
In rodents an intravenous administration of viableCryptococcus (C.) neoformans cells frequently resulted in attachment of intravascular cryptococcal granulomas to inner walls of the large to medium-sized
veins of various organs, including the lungs, liver and spleen. In order to elucidate the pathogenesis of granulomatous changes,
the cells composing the intravascular granulomas were observed by electron microscopic peroxidase (PO) cytochemistry. The
granuloma composing cells could be divided into the following four types according to the pattern of endogenous peroxidase
activity: exudate macrophage (Mφ, type I), PO-negative Mφ (type II), resident Mφ (type III) and other inflammatory cells (type
IV). In the intravenous granulomas of the lung, the percentages of composed cells were 39.0% for type I, 57.9% for type II,
0% for type III and 3.1% for type IV. By contrast, in the interstitial granulomas in the lung, type III Mφs, possibly derived
from alveolar Mφs, played a significant role in granuloma formation. This may indicate that the intravascular granuloma is
almost composed of macrophages derived from monocytes rather than alveolar macrophages. The expression of ICAM-1 on endothelia
of the pulmonary veins was examined by immunoelectron microscopy. An immunogold labeling index was significantly augmented
on the surface of endothelia in response to intravenous challenge ofC. neoformans. The intravascular granuloma demonstrates that the monocytes develop into the granuloma-composing macrophages and suppress
the cryptococcal activities even hi the peripheral blood resulting in an assistance of endothelial functions. 相似文献
34.
The effects of dwarf bamboo,Sasa, cover on the initial morrality of hardwood seedlings were investigated by transplanting 1-year-old beech (Fagus crenata) and current-year oak (Quercus mongolica var.grosseserrata) seedling to three different stands; old-growth beech and secondary oak forests withSasa undergrowth, and aSasa grassland in a grassland-forest series near the top of Mt Jippo, southwestern Japan. The most frequent cause of seedling
morrality was gnawing of the stems by rodents. In the beech forest, the gnawing was more likely to occur underSasa cover, suggesting that it provides a good habitat for rodents on the beech forest floor. TheSasa under growth may thus play an imporrant role in regeneration of beech forest. In the oak floor, mortality of both species
was low and only a little gnawing occurred during a year. However, no natural oak seedling were found in the forest even after
a mast year. This may be because most of the acorns disappeated before establishment. The early-stage demography of hardwood
seedling as oak may thus play an imporrant role in regeneration of oak forest. In theSasa grassland where the seed supply is small, almost all of the seedlings died fromo gnawing regardless of the presence ofSasa cover. These factors prevent the recruitment of a sizable seedling bank. Rodents may thus play an imporrant role in maintenance
of theSasa grassland. 相似文献
35.
It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in
Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when
cucumber (Cucumis sativus L. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24°C in the dark. Simultaneously, sedimented amyloplasts
(putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately
adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg,
contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation
may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented
amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation. 相似文献
36.
Hideyuki Takahashi 《Plant and Soil》1994,165(2):301-308
We have studied hydrotropism and its interaction with gravitropism in agravitropic roots of a pea mutant and normal roots of peas (Pisum sativum L.) and maize (Zea mays L.). The interaction between hydrotropism and gravitropism in normal roots of peas or maize were also examined by nullifying the gravitropic response on a clinostat and by changing the stimulus-angle for gravistimulation. Depending on the intensity of both hydrostimulation and gravistimulation, hydrotropism and gravitropism of seedling roots strongly interact with one another. When the gravitropic response was reduced, either genetically or physiologically, the hydrotropic response of roots became more unequivocal. Also, roots more sensitive to gravity appear to require a greater moisture gradient for the induction of hydrotropism. Positive hydrotropism of roots occurred due to a differential growth in the elongation zone; the elongation was much more inhibited on the moistened side than on the dry side of the roots. It was suggested that the site of sensory perception for hydrotropism resides in the root cap, as does the sensory site for gravitropism. Furthermore, an auxin inhibitor, 2,3,5-triiodobenzoic acid (TIBA), and a calcium chelator, ethyleneglycol-bis-(-aminoethylether)-N,N,N,N- tetraacetic acid (EGTA), inhibited both hydrotropism and gravitropism in roots. These results suggest that the two tropisms share a common mechanism in the signal transduction step. 相似文献
37.
Akemi Tsuda Masatoshi Ito Kazuko Kishi Hideyuki Shiraishi Hideo Tsuda Chuzo Mori 《Neurochemical research》1994,19(1):1-4
To investigate the mechanism of penicillin-induced convulsions, we have studied the effects of penicillin G (PC-G) on GABA-gated chloride ion influx in brain microsac preparations of mice. In the presence of 10–4 M GABA, PC-G inhibited GABA-gated chloride ion influx in a dose-dependent manner. The dose-response curve for GABA in the presence of 10–3 M PC-G was shifted rightward and there was a decrease in maximum response. The inhibitory effects of PC-G were not reversed by RO 15-1788, an antagonist of benzodiazepine (BZ) receptors, but were reversed by washing the microsac membranes. Therefore, PC-G probably exerts its proconvulsant effect by inhibiting GABA-gated chloride ion influx. However, it appears not to act through the BZ receptor of the GABA/BZ receptor complex. 相似文献
38.
Naoko Miyano-Kurosaki Hideki Nakashima Koji Ichiyama Kazuhiko Inazawa Hidenori Tabata Hideyuki Tanabe Kiyotaka Ohnishi Hiroshi Mizusawa Yukako Ohshiro Naoki Yamamoto 《Microbiology and immunology》1994,38(10):813-818
A subclonal cl.1–14 cell was established from a monocytic cell line U937 by a limiting dilution method. The anti-HIV-1 activity of some antiviral compounds was evaluated in HIV-1-infected cl.1–14 cells. The results demonstrated that although AZT was a potent inhibitor of HIV-1 replication in cl.1–14 cells, its 50% effective concentration (EC50) values was 80 times higher than that in HIV-1 infected MT-4 cells; the EC50 of AZT was 0.16 μM and 0.002 μM in cl.1–14 and MT-4 cells, respectively. In contrast, the anti-HIV-1 activity of ddA, ddI and ddC in cl.1–14 cells was comparable to that in MT-4 cells. The antiviral activity of nevirapine, dextran sulfate, curdlan sulfate and T22 did not differ significantly between the cl. 1–14 and MT-4 cells. The antiviral activity of several compounds in the HIV-1-infected cl.1–14 cells was similar to that in the HIV-1jr -fl -infected human peripheral macrophages. Our results suggest that cl.1–14 cell cultures are very useful for estimating antiviral activity and more advantageous than the use of peripheral blood macrophages. 相似文献
39.
40.
Nitric Oxide Reversibly Suppresses Xanthine Oxidase Activity 总被引:10,自引:0,他引:10
Masami Fukahori Kohji Ichimori Hideyuki Ishida Hiroe Nakagawa Haruka Okino 《Free radical research》1994,21(4):203-212
The effects of nitric oxide (NO) on xanthine oxidase (XOD) activity and the site(s) of the redox center(s) affected were investigated. XOD activity was determined by superoxide (O2-) generation and uric acid formation. NO reversibly and dose-dependently suppressed XOD activity in both determination methods. The suppression interval also disclosed a dose-dependent prolongation. The suppression occurred irrespective of the presence or absence of xanthine; indicating that the reaction product of NO and O2-, peroxynitrite, is not responsible for the suppression. Application of synthesized peroxynitrite did not affect XOD activity up to 2 μM. Methylene blue, which is an electron acceptor from Fe/S center, prevented the NO-induced inactivation. The results indicate that NO suppresses XOD activity through reversible alteration of the flavin prosthetic site. 相似文献