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971.
The dipole moments of small protein molecules were determined experimentally in order to validate the calculated dipole moments by previous investigators. We found that the agreements are satisfactory for some proteins. There are, however, many proteins for which the agreement is less than satisfactory. In order to find the cause of the disagreement, the dipole moments of these proteins were recalculated using the Brookhaven Protein Data Bank. We calculated the dipole moment due to fixed surface charges and the bond moments of all the carbonyl groups in main chain and side chains. The calculation consists of the mean moments and their mean square fluctuations. In addition, we investigated the effect of electrostatic interactions between charged sites for several proteins. These results show that incorporation of the interactions does not affect substantially the calculated dipole moments. The rms fluctuation of the dipole moment is found to be small but not negligible. In conclusion, recalculated dipole moments are in good agreement with the observed values. © 1993 John Wiley & Sons, Inc. 相似文献
972.
973.
Pathogenesis of Rhodococcus equi infection in mice: Roles of virulence plasmids and granulomagenic activity of bacteria 总被引:2,自引:0,他引:2
Shinji Takai Hiroo Madarame Chizuko Matsumoto Maki Inoue Yukako Sasaki Yoshihisa Hasegawa Shiro Tsubaki Akio Nakane 《FEMS immunology and medical microbiology》1995,11(3):181-190
Abstract Virulence of Rhocococcus equi ATCC 33701 and its plasmid-cured derivative ATCC 33701P− was compared in BALB/c and C3H/HeJ mice in terms of bacterial growth kinetics and histological changes in the liver, spleen and lungs, and humoral immune responses. Injection with a sublethal dose of 106 ATCC 33701 in mice resulted in microabscess formation after rapid multiplication in the liver and spleen by day 4, and then the bacteria were gradually eliminated with the formation of granuloma and the production of specific antibodies against 15- to 17-kDa antigens of the virulent bacteria. By contrast, ATCC 33701P− was avirulent as shown by early elimination of viable bacteria and no evidence of net multiplication in the organs. Histopathological changes consisted of only slight, transient infiltration of neutrophils and macrophages in the liver. Although live ATCC 33701P− did not evoke any humoral or histological responses in the mice, a large inoculum (108 ) of killed ATCC 33701 and ATCC 33701P− resulted in the formation of granuloma in the liver and accelerated extramedullary hemopoiesis in the spleen. These results suggest that the pathogenesis of R. equi infection involves at least two important virulence determinants, both of which play critical roles in the disease: one is the virulence plasmid, which is required for R. equi to resist and grow within host cells; and the other is the granulomagenic activity that is related to the lipids and nature of the cell wall of the species, which induces the characteistic pathological changes. 相似文献
974.
Vegetation recovery patterns in early volcanic succession 总被引:1,自引:0,他引:1
Shiro Tsuyuzaki 《Journal of plant research》1995,108(2):241-248
Permanently plots were monitored from 1983 to the present on Mount Usu after the eruptions of 1977–78 which destroyed the
pre-eruption vegetation by 1–3 m thick accumulations of ash and pumice in order to clarify the processes and mechanisms of
succession. Until now, 163 species were recorded in the summit area. Most of these species were derived from vegetative reproduction
throughout the volcanic deposits. Vegetative reproduction plays a major role on increases in cover. Although long-distance
seed-dispersal species could immigrate to the crater basin, their cover increase was slow. Seedbank species only established
in gullies where the original topsoil was exposed by erosion. Most annuais were supplied by the seedbank in the original topsoil
and woody species originated via immigration, suggesting that the source greatly determines the species composition of establishing
vegetation. Annual seedlings showed low survival, while overwintering perennial seedlings steadily established. Ground surface
movements strongly restricted increases in plant cover and the distance from source vegetation was the principal determinant
of plant density. Due to differences in disturbance intensity, successional rates were higher in the stable substrates outside
gullies and lower on the exposed original topsoil in some gullies.
Recipient of the Botanical Society Award of Young Scientists, 1994 相似文献
975.
Endopeptidase activities during the differentiation of Zinniacells into tracheary elements (TEs) were examined with severalpeptidyl 4-methyl-7-coumarylamido (MCA) as substrates. The activitythat hydrolysed carbobenzoxy-Phe-Arg-MCA (Z-Phe-Arg-MCA) atpH 5 increased in a differentiation-related manner: this activity,which was not observed in freshly isolated mesophyll cells wasinduced by the combination of -naphthaleneacetic acid (NAA)and 6-benzyladenine (BA) that is necessary for differentiationof TEs, but not by NAA or BA alone. The activity in cells culturedin TE-inductive medium that contained both NAA and BA increasedvery rapidly between the 48th and 60th hours of culture, whenthe number of TE increased rapidly. A protease responsible forthis activity with a molecular mass of 30 kDa was partiallypurified from cells which had been cultured in the TE-inductivemedium and included many immature TEs. Strong inhibition by[L-3-trans-carboxyoxiran-2-carbonyl]-L-Leu-agmatin (E-64), andactivation by dithiothreitol (DTT) indicated that this proteasebelongs to a family of cysteine endopeptidases (EC 3.4.22).
1Present address: Department of Material and Biological Engineering,Tsuruoka National College of Technology, Inooka-Sawada 104,Tsuruoka, Yamagata, 997 Japan 相似文献
976.
Programming of cell death during xylogenesis 总被引:2,自引:0,他引:2
Hiroo Fukuda Yoriko Watanabe Hideo Kuriyama Shigemi Aoyagi Munetaka Sugiyama Ryo Yamamoto Taku Demura Atsushi Minami 《Journal of plant research》1998,111(2):253-256
Death of tracheary elements which compose vessels and tracheids is a typical example of programmed cell death in plants. Anin vitro system usingZinnia mesophyll cells which differentiate directly into tracheary elements has provided various types of data on the cell death
process. In this paper, we will summarize recent results obtained using theZinnia system and discuss the programming of cell death during tracheary element differentiation.
The extended abstract of a paper presented at the 13th International Symposium in Conjugation with Award of the International
Prize for Biology “Frontier of Plant Biology” 相似文献
977.
Tetsuo Mashima Hiroyuki Seimiya Zhihong Chen Shiro Kataoka Takashi Tsuruo 《Cytotechnology》1998,27(1-3):293-308
Various antitumor agents induce apoptotic cell death in tumor cells. Since the apoptosis program in tumor cells plays a critical
role in the chemotherapy-induced tumor cell killing, it is suggested that the defect in the signaling pathway of apoptosis
could cause a new form of multidrug resistance in tumor cells. This article describes the recent findings concerning the mechanisms
of chemotherapy-induced apoptosis and discusses the implication of apoptosis resistance in cancer chemotherapy.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
978.
Genetic dissection of ``OLETF', a rat model for non-insulin-dependent diabetes mellitus 总被引:3,自引:0,他引:3
Naohide Kanemoto Haretsugu Hishigaki Ayako Miyakita Keiko Oga Shiro Okuno Atsushi Tsuji Toshihisa Takagi Ei-ichi Takahashi Yusuke Nakamura Takeshi K. Watanabe 《Mammalian genome》1998,9(6):419-425
To elucidate the genetic factors underlying non-insulin-dependent diabetes mellitus (NIDDM), we performed genome-wide quantitative
trait locus (QTL) analysis, using the Otsuka Long-Evans Tokushima Fatty (OLETF) rat. The OLETF rat is an excellent animal
model of NIDDM because the features of the disease closely resemble human NIDDM. Genetic dissection with two kinds of F2 intercross
progeny, from matings between the OLETF rat and non-diabetic control rats F344 or BN, allowed us to identify on Chromosome
(Chr) 1 a major QTL associated with features of NIDDM that was common to both crosses. We also mapped two additional significant
loci, on Chrs 7 and 14, in the (OLETF × F344)F2 cross alone, and designated these three loci as Diabetes mellitus, OLETF type Dmo 1, Dmo2 and Dmo3 respectively. With regard to suggestive QTLs, we found loci on Chrs 10, 11, and 16 that were common to both crosses, as well
as loci on Chrs 5 and 12 in the (OLETF × F344)F2 cross and on Chrs 4 and 13 in the (OLETF × BN)F2 cross. Our results showed that NIDDM in the OLETF rat is polygenic and demonstrated that different genetic backgrounds could
affect ``fitness' for QTLs and produce different phenotypic effects from the same locus.
Received: 9 October 1997 / Accepted: 29 January 1998 相似文献
979.
980.
Silvia Yuko Eguchi Hiroyuki Nakata Naomichi Nishio Shiro Nagai 《Applied microbiology and biotechnology》1984,20(3):213-217
Summary The resting cells of methanogen strain HU could be used as biocatalyser for converting exoge nous NADP+ into NADPH, using either formate or hydrogen as electron donor. To enhance the conversion efficiency of NADPH from NADP+, several inhibitors of methylcoenzyme M reductase were used in order to avoid further oxidation of NADPH to CH4. When methyl viologen (7.5 mol ml-1) was added to the reaction mixture (17 mg of dry cells, 2 mg Triton X-100, 294 mol of Na-formate and 12 mol of NADP+ per ml reaction mixture), 9.6 mol ml-1 NADPH (80% yield) could be produced in a 2-h reaction, compared with 7.2 mol ml-1 NADPH (60% yield) in a 6-h reaction in the absence of methyl viologen. Molecular hydrogen istead of formate also served as electron donor to convert NADP+ into NADPH. A gas mixture of H2/N2 (75/25) yielded 9.8 mol ml-1 NADPH (82% yield) in a 3-h reaction in the absence of formate, suggesting that H2 might be a promising, inexpensive electron donor for this reaction system. 相似文献