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排序方式: 共有121条查询结果,搜索用时 31 毫秒
1.
Atrophy of the lymphoid tissues of mice induced by extracts of the submaxillary gland 总被引:2,自引:0,他引:2
2.
T Taoka M Tokuda T Tasaka O Hatase S Irino A W Norman 《Biochemical and biophysical research communications》1990,170(3):1151-1156
To clarify the role of protein kinase C and protein kinase A in cell proliferation and differentiation, the effects of K252a and its derivatives (K252b, KT5720), which have different inhibitory activity to these protein kinases, on the proliferation and differentiation of HL-60 cells were investigated. The proliferation and DNA synthesis of the HL-60 cells were inhibited by K252a in a dose dependent manner. However, K252b and KT5720 which are more specific inhibitors of protein kinase C or protein kinase A, respectively, had no observable effect on cell proliferation. K252a (40nM) enhanced the differentiation of HL-60 cells induced by 1,25(OH)2D3, retinoic acid and DMSO. K252b and KT5720 did not affect 1,25(OH)2D3-induced differentiation. K252a significantly inhibited the differentiation induced by PMA. These results demonstrate that K252a but not its derivatives can function as an antitumor drug and enhancer of the differentiation induced by various inducers. 相似文献
3.
Seven biochemical groups were found among strains previously labeledSerratia liquefaciens (groups C1ab, C1c, C1d, EB, RB, RQ, and Adc). Comparison of biochemical data with DNA relatedness data allowed the definition (or redefinition) of threeSerratia species:Serratia liquefaciens sensu stricto (group C1ab),Serratia proteamaculans (groups C1c, EB, RB, and RQ), andSerratia grimesii sp. nov. (groups C1d and Adc). Biochemical group RQ, which is genomically related toS. proteamaculans at the borderline of species level, is proposed as a new subspecies ofS. proteamaculans (Serratia proteamaculans subsp.quinovora). Group Adc (3 strains) is also ambiguously related toS. grimesii, but no other proposal is made pending additional studies. The type strains of the newly named taxa,S. grimesii andS. proteamaculans subsp.quinovora, are respectively ATCC 14460 and strain 4364 (= CIP 8195 = ATCC 33765). 相似文献
4.
Akira Mizoguchi Shintaro Ohsumi Katuji Kobayashi Naoki Okamoto Nobuto Yamada Ken Tateishi Yoshinori Fujimoto Hiroshi Kataoka 《PloS one》2013,8(4)
Diapause is a programmed developmental arrest that has evolved in a wide variety of organisms and allows them survive unfavorable seasons. This developmental state is particularly common in insects. Based on circumstantial evidence, pupal diapause has been hypothesized to result from a cessation of prothoracicotropic hormone (PTTH) secretion from the brain. Here, we provide direct evidence for this classical hypothesis by determining both the PTTH titer in the hemolymph and the PTTH content in the brain of diapause pupae in the cabbage army moth Mamestra brassicae. For this purpose, we cloned the PTTH gene, produced PTTH-specific antibodies, and developed a highly sensitive immunoassay for PTTH. While the hemolymph PTTH titer in non-diapause pupae was maintained at high levels after pupation, the titer in diapause pupae dropped to an undetectable level. In contrast, the PTTH content of the post-pupation brain was higher in diapause animals than in non-diapause animals. These results clearly demonstrate that diapause pupae have sufficient PTTH in their brain, but they do not release it into the hemolymph. Injecting PTTH into diapause pupae immediately after pupation induced adult development, showing that a lack of PTTH is a necessary and sufficient condition for inducing pupal diapause. Most interestingly, in diapause-destined larvae, lower hemolymph titers of PTTH and reduced PTTH gene expression were observed for 4 and 2 days, respectively, prior to pupation. This discovery demonstrates that the diapause program is already manifested in the PTTH neurons as early as the mid final instar stage. 相似文献
5.
6.
D. Fernández K. Irino M.E. Sanz N.L. Padola A.E. Parma 《Letters in applied microbiology》2010,51(4):377-382
Aims: To feno‐genotypically characterize the Shiga toxin‐producing Escherichia coli (STEC) population in Argentinean dairy cows. Methods and Results: From 540 STEC positive samples, 170 isolates were analyzed by multiplex PCR and serotyping. Of these, 11% carried stx1, 52%stx2 and 37%stx1/stx2. The ehxA, saa and eae were detected in 77%, 66% and 3%, respectively. Thirty‐five per cent of strains harboured the profile stx1, stx2, saa, ehxA and 29%stx2, saa, ehxA. One hundred and fifty‐six strains were associated with 29 different O serogroups, and 19 H antigens were distributed among 157 strains. STEC O113:H21, O130:H11 and O178:H19 were the most frequently found serotypes. The STEC O157:H7 were detected in low rate and corresponded to the stx2+, eae+, ehxA+ virulence pattern. Conclusions: We detected a diversity of STEC strains in dairy cattle from Argentina, most of them carrying genes linked to human disease. Significance and Impact of the study: The non‐O157 STEC serotypes described in this study are associated worldwide with disease in humans and represent a risk for the public health. For this, any microbiological control in dairy farms should be targeted not only to the search of O157:H7 serotype. 相似文献
7.
Farah SM de Souza EM Pedrosa FO Irino K da Silva LR Rigo LU Steffens MB Pigatto CP Fadel-Picheth CM 《Letters in applied microbiology》2007,44(6):607-612
AIMS: To investigate the prevalence and characteristics of Shiga toxin-producing Escherichia coli (STEC) in cattle from Paraná State, southern Brazil. METHODS AND RESULTS: One hundred and seven faeces cattle samples were cultured on Sorbitol-MacConkey agar. Escherichia coli colonies were tested for production of Shiga toxin using Vero-cell assay. A high prevalence (57%) of STEC was found. Sixty-four STEC were serotyped and examined for the presence of stx(1), stx(2), eae, ehxA and saa genes and stx(2) variants. The isolates belonged to 31 different serotypes, of which three (O152:H8, O175:H21 and O176:H18) had not previously been associated with STEC. A high prevalence of stx(2)-type genes was found (62 strains, 97%). Variant forms found were stx(2), stx(2c), stx(2vhb), stx(2vO111v/OX393) and a form nonclassifiable by PCR-RFLP. The commonest genotypes were stx(2)ehxA saa and stx(1)stx(2)ehxA saa. CONCLUSIONS: A high frequency of STEC was observed. Several strains belong to serotypes previously associated with human disease and carry stx(2) and other virulence factors, thus potentially representing a risk to human health. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study of STEC in Paraná State, and its findings emphasize the need for proper cattle handling to prevent human contamination. 相似文献
8.
Cergole-Novella MC Nishimura LS Dos Santos LF Irino K Vaz TM Bergamini AM Guth BE 《FEMS microbiology letters》2007,274(2):329-334
The distribution of virulence markers related to cytolethal distending toxin-V (CDT-V), subtilase cytotoxin (SubAB), the enterohemorrhagic Escherichia coli factor for adherence (Efa1), the adhesin similar to IrgA (Iha), the long polar fimbriae (LpfO113), the autoagglutinating adhesin (Saa), and the protein required for full expression of adherence of O157:H7 Sakai strain (ToxB) was investigated in 121 Shiga toxin-producing E. coli (STEC) strains isolated in Brazil. STEC strains were isolated from human infections (n=49), cattle (n=68) and ground meat samples (n=4). Overall, the lpfA(O113), iha, efa1, saa, and toxB sequences were observed in 89.2%, 87.6%, 47.1%, 43%, and 13.2% of the strains, respectively. The genes efa1 (96.6%) and toxB (27%) were only identified among eae-positive strains, while saa (83.8%), cdt-V (12.9%), and subAB (48.4%) just occurred in eae-negative STEC strains. STEC strains harboring cdt-V and subAB were for the first time described in the South American subcontinent. In addition, the simultaneous presence of cdt-V and subAB has not been previously reported, nor the presence of subAB in STEC O77, O79, O105, O174, and O178 serogroups. A diversity of virulence profiles was observed among the STEC strains studied. The most prevalent profile observed among eae-positive STEC strains mainly isolated from humans was eae efa1 iha lpfA(O113), whereas iha lpfA(O113) saa ehxA subAB prevailed among eae-negative STEC strains, mostly isolated from cattle and foods. 相似文献
9.
The division of labor between template and catalyst is a fundamental property of
all living systems: DNA stores genetic information whereas proteins function as
catalysts. The RNA world hypothesis, however, posits that, at the earlier stages
of evolution, RNA acted as both template and catalyst. Why would such division
of labor evolve in the RNA world? We investigated the evolution of DNA-like
molecules, i.e. molecules that can function only as template, in minimal
computational models of RNA replicator systems. In the models, RNA can function
as both template-directed polymerase and template, whereas DNA can function only
as template. Two classes of models were explored. In the surface models,
replicators are attached to surfaces with finite diffusion. In the compartment
models, replicators are compartmentalized by vesicle-like boundaries. Both
models displayed the evolution of DNA and the ensuing division of labor between
templates and catalysts. In the surface model, DNA provides the advantage of
greater resistance against parasitic templates. However, this advantage is at
least partially offset by the disadvantage of slower multiplication due to the
increased complexity of the replication cycle. In the compartment model, DNA can
significantly delay the intra-compartment evolution of RNA towards catalytic
deterioration. These results are explained in terms of the trade-off between
template and catalyst that is inherent in RNA-only replication cycles: DNA
releases RNA from this trade-off by making it unnecessary for RNA to serve as
template and so rendering the system more resistant against evolving parasitism.
Our analysis of these simple models suggests that the lack of catalytic activity
in DNA by itself can generate a sufficient selective advantage for RNA
replicator systems to produce DNA. Given the widespread notion that DNA evolved
owing to its superior chemical properties as a template, this study offers a
novel insight into the evolutionary origin of DNA. 相似文献
10.
We reported previously that phospholipase C (PLC) delta4 is required for calcium mobilization in the zona pellucida-induced acrosome reaction in sperm. Here we focused on the function of the C2 domain of PLCdelta4 and report that glutamate receptor-interacting protein1 (GRIP1) was identified as a binding protein of the PLCdelta4-C2 domain on yeast two-hybrid screening. Physiological interaction of GRIP1 with PLCdelta4 in mouse testis was confirmed by immunoprecipitation with anti-PLCdelta4 antibodies and the association seemed to correlate with the maturation stage of sperm. We also determined that a PDZ-binding motif at the C-terminus of the PLCdelta4-C2 domain is responsible for GRIP1 binding, whereas the sixth or seventh PDZ domain of GRIP1 is essential and sufficient for association with the PLCdelta4-C2 domain. These results indicate that PLCdelta4 binds via its C2 domain to the PDZ6 or PDZ7 domain of GRIP1, and that this association may play a role in spermatogenesis. 相似文献