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91.
Entry into mitosis of the eukaryotic cell cycle is driven by rising cyclin-dependent kinase (Cdk) activity. During exit from mitosis, Cdk activity must again decline. Cdk downregulation by itself, however, is not able to guide mitotic exit, if not a phosphatase reverses mitotic Cdk phosphorylation events. In budding yeast, this role is played by the Cdc14 phosphatase. We are gaining an increasingly detailed picture of its regulation during anaphase, and of the way it orchestrates ordered progression through mitosis. Much less is known about protein dephosphorylation during mitotic exit in organisms other than budding yeast, but evidence is now mounting for crucial contributions of regulated phosphatases also in metazoan cells. 相似文献
92.
Diana M. Pitterle Young-Chul Kim Ethel M.C. Jolicoeur Youjia Cao Kathy C. O'Briant Gerold Bepler 《Mammalian genome》1999,10(9):916-922
LOH11A is a region of Chromosome (Chr) 11p15.5 where 75% of lung cancers show loss of heterozygosity (LOH). Clinical and
cell biological studies suggest that LOH11A contains a tumor/metastasis suppressor gene. We have mapped this region (650 kb)
using overlapping genomic P1/PAC/BAC clones, and one of the genes that we have identified is RRM1. This gene encodes the large
subunit (M1) of ribonucleotide reductase, the heterodimeric enzyme that catalyzes the rate-limiting step in deoxyribonucleotide
synthesis. By comparing our genomic sequences with the previously published cDNA, we have found that the human gene is composed
of 19 exons. It is oriented telomere to centromere and is Alu rich. In order to verify that RRM1 maps within the boundaries
of LOH11A, we assessed the frequency of LOH at a SacI polymorphism within intron IX of the gene. We observed LOH in 48% (15/31) of informative lung tumor specimens. To determine
whether RRM1 was mutated in tumors, SSCP analysis of the 19 RRM1 exons was performed. No mutations were revealed in 12 pairs
of normal and tumor DNA samples. Immunoblots on protein extracts from normal/tumor pairs indicated that a protein of the expected
size was present in both. Our conclusion is that RRM1 lies within the LOH11A region, but that its exons are not mutated in
tumors. The potential for RRM1 to act as a tumor suppressor is discussed.
Received: 18 September 1998 / Accepted: 10 May 1999 相似文献
93.
Ethel R. Pereira Karen Frudd Walid Awad Linda M. Hendershot 《The Journal of biological chemistry》2014,289(6):3352-3364
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Clostridium botulinum Type A Growth and Toxin Production in Media and Process Cheese Spread 下载免费PDF全文
Jorge Briozzo Ethel Amato de Lagarde Jorge Chirife Jos L. Parada 《Applied microbiology》1983,45(3):1150-1152
We found that Clostridium botulinum type A grew well and produced toxin in media with a water activity (aw) of 0.972 or 0.965 and a pH of 5.7, but no growth or toxin production was observed at or below an aw of 0.949 during incubation at 30°C for 52 to 59 days. aw and pH values of media were adjusted to those of cheese spreads commercially produced. Solutes used to adjust aw included combinations of NaCl, cheese whey powder, emulsifying salt, sodium tripolyphosphate, and glycerol. In agreement with results obtained for media, toxin was produced in samples of cheese spread (aw, 0.970; pH, 5.7) at 30 to 70 days of incubation at 30°C. 相似文献
96.
Summary Specific proteolytic activities are known to be induced in Escherichia coli following irradiation. Consequently it seemed of interest to investigate whether variations in proteinase activities occur in yeast.Among the five most well known proteinases of Saccharomyces cerevisiae, we have found that proteinase B activity increases up to three times in wild-type RAD
+
yeast cells after a dose of 50 Jm-2 of 254 nm ultraviolet light (40% survival). Carboxypeptidase Y and aminopeptidase I (leucin aminopeptidase) activities were only moderately increased. Proteinase A activity was only slightly enhanced, while aminopeptidase II (lysin aminopeptidase) was unaffected in both RAD
+
strains studied.The observed post UV-increase in proteinase B activity was inhibited by cycloheximide and was dose dependent. Increases in proteinase B levels were independent of the activation method used to destroy the proteinase B-inhibitor complex present in the crude yeast extracts.A standard method for comparison of the postirradiation levels among different proteinases, strains and methods of activation is presented.Abbreviations UV
Ultraviolet
- BRIJ-35
Polyoxyethylene-23-lauryl ether
- EDTA
Ethylene diamine tetraacetic acid
- EGTA
Ethylene glycol bis (-aminoethyl ether) tetraacetic acid
- MOPS
3-[N-morpholine]propansulfonic acid
- HEPES
N-2-Hydroxyethylpiperazine-N-2-ethansulfonic acid
- Tris
Tris(hydroxy methyl)amino methane
- BTPNA
N-benzoyl-L-tyrosine-p-nitroanilide
- CP.Y
Carboxypeptidase Y
- Leu.AP
Leucin amino peptidase
- Lys.AP
Lysin amino peptidase
- DMFA
Dimethyl formamide
- CHX
Cycloheximide
- PMSF
Phenylmethyl sulfonyl fluoride
- TCA
Trichloroacetic acid
Code Number of Enzymes EC. 3.4.23.8
Proteinase A
- EC. 3.4.22.9
Proteinase B
- EC. 3.4.12.8
Carboxypeptidase Y
- EC. 3.4.24.4
Thermolysin
- EC. 3.4.23.1
Pepsin A 相似文献
97.
Crosby Bill Colson Anne-Marie Briquet Michel Moustacchi Ethel Goffeau André 《Molecular genetics and genomics : MGG》1978,167(2):227-234
Molecular Genetics and Genomics - The mutant uvsρ 72 of Saccharomyces cerevisiae UV-sensitive for rho- production displays slower growth on media containing non-fermentable carbon sources such... 相似文献
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