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961.
Diapause egg production was examined in non-diapause egg producers by implantation of various cephalic organs into pharate adults 4 days after larval-pupal ecdysis. The implantation of five pairs of corpora cardiaca or corpora allata induced a great amount of egg diapause. Implantation of these organs was effective in inducing egg diapause even when the suboesophageal ganglion of the recipients had been removed, although the effect of the corpora allata decreased moderately. The injection of juvenile hormone into 4-day-old pharate adults did not greatly increase production of diapause eggs. 相似文献
962.
There is considerable evidence suggesting that compartmentalized functional pools of cholesterol in the liver contribute differently to the formation of bile acids as the precursor. The present paper deals with the incorporation of [1-14C]acetate and of [1,2-3H]cholesterol carried on lipoproteins (LDL and HDL) into biliary bile acids in perfused rat livers and bile-fistula rats. The results showed that endogenous cholesterol synthesized newly from [1-14C]acetate in the liver was incorporated into both cholic acid and chenodeoxycholic acid in a similar way, while exogenous lipoprotein-[1,2-3H]cholesterol delivered to hepatocytes from hepatic circulation was incorporated into chenodeoxycholic acid at a higher rate. 相似文献
963.
Yohei Hashimoto Yukiko Ohta Hiroyuki Ishizone Masayuki Kuriyama Masaru Ogura 《Phytochemistry》1982,21(9):2335-2337
Periandrin III, a new sweet triterpene glycoside of the roots of Pepiandra dulcis, has been shown to possess the structure 3-β-O-[β-d-g 相似文献
964.
Multiple copies of the proB gene enhance degS-dependent extracellular protease production in Bacillus subtilis. 总被引:5,自引:5,他引:0
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Bacillus subtilis secretes extracellular proteases whose production is positively regulated by a two-component regulatory system, DegS-DegU, and other regulatory factors including DegR. To identify an additional regulatory gene(s) for exoprotease production, we performed a shotgun cloning in the cell carrying multiple copies of degR and found a transformant producing large amounts of the exoproteases. The plasmid in this transformant, pLC1, showed a synergistic effect with multiple copies of degR on the production of the extracellular proteases, and it required degS for its enhancing effect. The DNA region responsible for the enhancement contained the proB gene, as shown by restriction analyses and sequence determination. The proB gene encoding gamma-glutamyl kinase was followed by the proA gene encoding glutamyl-gamma-semialdehyde dehydrogenase at an interval of 39 nucleotides, suggesting that the genes constitute an operon. pLC1 contained the complete proB gene and a part of proA lacking the proA C-terminal region. It was also found that proB on the chromosome showed a synergistic effect with multiple copies of degR. We consider on the basis of these results that the metabolic intermediate, gamma-glutamyl phosphate, would transmit a signal to DegS, resulting in a higher level of phosphorylated DegU. Possible involvement of DegR in this process is discussed. 相似文献
965.
Summary We have developed an improved isotope-filtered pulse scheme in combination with a double-tuned filter, a hyperbolic secant inversion pulse, and a z-filter with a pulsed field gradient. These filtering pulse schemes have been incorporated into several one-, two-, and three-dimensional experiments, which were applied to the 13C/15N uniformly labeled N-terminal SH3 domain of Grb2 complexed with the unlabeled Sos-derived peptide. The proton resonances of the Sos-derived peptide were unambiguously assigned using isotope-filtered DQF-COSY, TOCSY and NOESY spectra. Furthermore, in the isotope-filtered, isotope-edited 3D NOESY spectrum, intermolecular NOEs between the labeled protein and the unlabeled peptide could be identified. Through these applications, we demonstrate the high filtering efficiency of the presented pulse scheme. 相似文献
966.
We have previously reported that the MukB protein is essential for chromosome partitioning inEscherichia coli and thatmukB mutants produce anucleate cells and are temperature-sensitive for colony formation. ThemukB gene maps at 21 min on theE. coli chromosome andsmtA-mukF-mukE-mukB genes might comprise an operon, which is transcribed in a clockwise direction. Here, we report thatmukF andmukE null mutants are both temperature-sensitive for colony formation and produce anucleate cells even at the permissive temperature. These phenotypes are the same as those observed in themukB null mutant. The primary sequence of MukF includes a leucine zipper structure and an acidic domain. Mutational analysis revealed that both are required for MukF function. When the MukF protein was overproduced in the wild-type strain, anucleate cells were produced. In contrast, overproduction of either MukE or MukB did not cause the defect. In null mutants for themukF, mukE, andmukB genes, the synchronous initiation of chromosome replication was not affected. The mini-F plasmid was as stably maintained in these mutants as in the wild-type strain. These results indicate that the MukF, MukE, and MukB proteins are involved in the chromosome partitioning steps, but are not required for mini-F plasmid partitioning. 相似文献
967.
Junichiro Matsuda Osamu Suzuki Akihiro Oshima Atsuo Ogura Yoko Noguchi Yoshie Yamamoto Toshihiko Asano Kazuhiro Takimoto Kazuko Sukegawa Yoshiyuki Suzuki Masaharu Naiki 《Glycoconjugate journal》1997,14(6):729-736
GM1-gangliosidosis is a progressive neurological disease in humans caused by deficiency of lysosomal acid β-galactosidase,
which hydrolyses the terminal β-galactosidic residue from ganglioside GM1 and other glycoconjugates. In this study, we generated
a mouse model for GM1-gangliosidosis by gene targeting in embryonic stem cells. The mouse homozygous for the disrupted β-galactosidase
gene showed β-galactosidase deficiency, presented with progressive spastic diplegia, and died of emaciation at 7–10 months
of age. Pathologically, PAS-positive intracytoplasmic storage was observed in neuronal cells of various areas in the brain.
Biochemical analysis revealed a marked accumulation of ganglioside GM1 and asialo GM1 in brain tissue. This animal model will
be useful for pathogenetic analysis and therapeutic trial of human GM1-gangliosidosis.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
968.
Escherichia coli mutant Y16 is a double mutant carrying thermosensitive ftsH and ftsI mutations.
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K J Begg T Tomoyasu W D Donachie M Khattar H Niki K Yamanaka S Hiraga T Ogura 《Journal of bacteriology》1992,174(7):2416-2417
The Escherichia coli mutant Y16, which shows thermosensitive colony formation and filamentation with reduced amounts of penicillin-binding protein 3 (PBP3), has mutations in the ftsI gene encoding PBP3 and in the ftsH gene. The ftsI mutation markedly reduces the amount of PBP3 at 42 degrees C, whereas the amount of the ftsH single mutant is slightly reduced. 相似文献
969.
Forty-three patients with malignant pleurisy due to lung cancer were entered into the trial to evaluate clinical efficacy of intrapleural instillation of recombinant interleukin-2 (RIL-2). Among 35 evaluable patients, serial cytological examinations of pleural effusion following the start of the treatment revealed disappearance of malignant cells in 26 (74%). Malignant cells were detected again in 7 of the 26, however, cytology remained negative in the other 19 patients for longer than 4 weeks. Pleural effusion disappeared roentogenographically in 13 of 35 evaluable patients. Additional 8 patients demonstrated marked decrease of pleural effusion. Complete response (CR) which means disappearance of both malignant cells and pleural effusion for longer than 4 weeks was obtained in 13 of the 35 patients (37%). No serious side effects were experienced in this trial. These results indicate that intrapleural RIL-2 is one of candidates to control intractable malignant pleurisy due to lung cancer. 相似文献
970.
The effect of pretreatment with ascorbic acid (vitamin C) on chromate-induced DNA damage, cytotoxicity, and enzyme inhibition as well as on the cellular reduction of chromium(VI) was investigated using Chinese hamster V-79 cells. Cellular pretreatment with nontoxic levels of 1 mM ascorbic acid for 24 h prior to exposure resulted in a significant increase (1.7-fold) in cellular levels of this vitamin. Alkaline elution assays demonstrated that this pretreatment decreased cellular levels of Na2CrO4-induced alkali-labile sites while the numbers of DNA-protein crosslinks produced by chromate increased. In colony-forming assays, pretreatment with ascorbic acid enhanced the cytotoxicity of chromate. However, the inhibition of glutathione reductase attributed to Na2CrO4 was attenuated by this pretreatment. Under the same experimental condition, the uptake of chromate in pretreated cells was found to increase. ESR studies revealed that cellular pretreatment with ascorbic acid reduced the level of chromium(V) intermediate and increased the level of chromium(III) complex, indicating that cellular reduction of chromium(VI) to chromium(III) was accelerated by this vitamin. These results suggest that ascorbic acid decreases chromate-induced alkali-labile sites and chromium inhibition of glutathione reductase, but it enhances DNA-protein cross-links and cytotoxicity caused by this metal through its ability to directly reduce chromium(VI). 相似文献