- Factors affecting pheromone induction of schizosaccharomyces pomba and isolation of pheromone induction mutants
-
Jun, Jai Hyun , Kim, Young Min , Lee, Joo Hun , Chung, In Kwon , Kim, Dae Myung
-
J. Microbiol. 1998;36(3):196-202.
-
-
-
 Abstract
 PDF
-
The mating pheromones of Schizosaccharomyces pombe are induced by nutritional starvation. However, this nutritional signaling pathway is largely unknown. For a complete understanding of pheromone induction, we examined the environmental factors affecting the induction afer cells were transferred to a nitrogen-starved medium. It appeared that the induction of mfm2 transcription was affected by the general environmental stress including incubation time, incubation temperature, and the growth phase of the cells. We identified 7 pheromone induction mutants by screening temperature sensitive mutant bank. Three of these mutants showed elongated cell shapes and one mutant exhibited swollen cell morphology in permissive culture, suggesting that their cell cycles were also impaired. Characterization of the pheromone induction mutants may elucidate the components required in nutritional signaling pathway leading to pheromone induction.
- Effect of Polyamines on Cellular Differintiation of N. gruberi: Inhibition of Translation of Tubulin mRNA
-
Yoo, Jin Uk , Kwon, Kyung Soon , Cho, Hyun Il , Kim, Dae Myung , Chung, In Kwon , Kim, Young Min , Lee, Tae HO , Lee, Joo Hun
-
J. Microbiol. 1997;35(4):315-322.
-
-
-
Abstract
PDF
-
The effects of a polyamine, spermine, on the differentiation of Naegleria gruberi amebas into flagellates were tested. Addition of spermine at early stages of differentiation (until 40 min after the initiation of differentiation) completely inhibited the differentiation. To understand the inhibition mechanism, we examined the effect of spermine treatment on the transcription and translation of differentiation-specific genes during differentiation. Addition of spermine at early stages did not inhibit the accumulation of two differentiation-specific mRNAs, α-tubulin and Class I mRNA, significantly, but rather prevented the rapid degradation of the mRNAs in later overall protein synthesis partially and gradually. However, translation of the α-tubulin mRNA was completely inhibited. These data suggest that the inhibition of differentiation of N. gruberi by spermine treatment did not result from the inhibition of transcription of differentiation-specific genes but from the specific inhibition of translation of the mRNAs during the differentiation.
- Isolation and characterization of pre-tRNA^Val splicing Mutants of Schizosaccharomyces pombe
-
Hwang, Ku Chan , Kim, Dae Myung
-
J. Microbiol. 1997;35(4):334-340.
-
-
-
Abstract
PDF
-
A collection of 132 temperature sensitive (ts) mutants was generated by the chemical mutagenesis of Schizosaccharomyces pombe wild type strain and screened for tRNA splicing defects on Northern blots by hybridization with an oligonucleotide that recognizes the exon of the S. pombe tRNA^Val as a probe. We identidied 6 mutants which accumulate precursor tRNA^Val. Among them, 2 mutants exhibited remarkable morphological differences compared to wild type cells. One tRNA splicing mutant showed elongated cell shape in permissive as well as non-permissive cultures. The other mutant exhibited shortened cell morphology only in nonpermissive culture. The total RNA pattern in the splicing mutants appeared to be normal. Genetic analysis of four tRNA^Val splicing mutants demonstrated that the mutation reside in different genes.
- Growth on methanol of a carboxydobacterium, acinetobacter sp. strain JC1 DSM 3803
-
Ro, Young Tae , Seo, Jae Goo , Lee, Joo Hun , Kim, Dae Myung , Chung, In Kwon , Kim, Tae Ue , Kim, Young Min
-
J. Microbiol. 1997;35(1):30-39.
-
-
-
Abstract
PDF
-
Acinetobacter sp. strain JC1 DSM 3803, a carboxydobacterium, was found to grow methylotrophically at the expense of methanol and methlamine, but not of methane, formaldehyde, formate, dimethylamine, or trimethylamine, as the sole source of carbon and energy. The doubling times of the bacterium growing on methanol (0.5% v/v) and methylamine (0.5% w/v) at 30℃ and pH 6.8 were 4.8 h and 5.7 h respectively. Cells grown on methanol, however, failed to show typical methanol dehydrogenase and oxidase activities. The cell was found to contain no c-type cytochromes. Cells grown on methanol exhibited higher catalase activity than those grown on pyruvate or glucose. The catalase present in the cells also exhibited peroxidase activity. The catalase activity, growth on methanol of the cell, and oxygen consumption by methanol-grown maldehyde dehydrogenase, formaldehyde reductase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase activities were detected from cells grown on methanol.
|
MSK
