• Journal of Microbiology
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• 제35권1호
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• pp.61-65
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• 1997

A novel strategy was developed for isolating suppressors from sporulation-deficient mutants. The mutation in the BCY1 gene, which codes for the regulatory subunit of cAMP-dependent protein kinase, when homozygous, results in diploids being meiosis and sporulation deficient. Two plasmids, YCp-MAT.alpha. and YEp-SPOT7-lacZ, were introduced into MAT.alpha. BCY1$\^$+/ or MAT.alpha. bcy1 haploid cells. The transformant of the BCY1$\^$+/ haploid cell produced .betha.-galactosidase under nutrient starvation, but the bcy1 transformant did not. Using this system, the mutagenesis experiment performed on the bcy1 transformant strain resulted in a number of sporulation mutants that produced .betha.-galactosidase under nutrient starvation. One complementation group, sob1, was identified from the isoalted suppressor mutants and characterized as a single recessive mutation by tetrad analysis. Genetic analysis revealed that the sob1 mutation suppressed the sporulation deficiency, the failure to arrest at the G1 phase of the cell cecle, and the sensitivity to heat or nitrogen starvation caused by the bcy1 mutation. However, the sob1 mutation did not suppress the sporulation deficiency of ime1 and of ime2 diploids. These results suggest that the sob1 mutation affects a gene which functions as a downstream regulator in both meiosis and cell cycle regulation.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.405-411
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• 2017

Homologous recombination occurs between homologous chromosomes and is significantly involved in programmed double-strand break (DSB) repair. Activation of two recombinases, Rad51 and Dmc1, is essential for an interhomolog bias during meiosis. Rad51 participates in both mitotic and meiotic recombination, and its strand exchange activity is regulated by an inhibitory factor during meiosis. Thus, activities of Rad51 and Dmc1 are coordinated to promote homolog bias. It has been reported that Hed1, a meiosis-specific protein in budding yeast, regulates Rad51-dependent recombination activity. Here, we investigated the role of Hed1 in meiotic recombination by ectopic expression of the protein after pre-meiotic replication in Saccharomyces cerevisiae. DNA physical analysis revealed that the overexpression of Hed1 delays the DSB-to-joint molecule (JM) transition and promotes interhomolog JM formation. The study indicates a possible role of Hed1 in controlling the strand exchange activity of Rad51 and, eventually, meiotic crossover formation.

• Reproductive and Developmental Biology
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• 제34권4호
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• pp.275-281
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• 2010

The aim of this study was to investigate what protein(s) of porcine epididymal fluid (pEF) are able to enhance the nuclear maturation of porcine germinal vesicle (GV) oocytes in vitro. Proteins of pEF were fractionated by affinity, ion exchange, and gel filtration chromatography. Porcine cumulus-oocytes complexes (COC) from follicles were cultured in tissue culture medium (TCM 199) containing various fractions obtained by chromatography. Porcine COCs were also cultured in TCM 199 containing various meiosis inhibitors and pEF. After 24 or 48 h culture, oocytes were examined for evidence of GV breakdown, metaphase I, anaphase-telophase I, and metaphase II. When porcine COCs were cultured in the medium with meiosis inhibitor such as, dibutyryl cAMP (dbcAMP) and forskolin (Fo), more than 80% of oocytes were unable to resume meiosis. However, porcine COCs supplemented with pEF were able to overcome the inhibitory effect of dbcAMP and Fo. Maturation rate of oocytes was significantly (p<0.05) increased in the media supplemented with cationic protein(s) during in vitro maturation than in those with anionic protein(s) (44.1% vs 20.0%). When oocytes were cultured in the TCM 199 with fractions obtained by gel filtration, the maturation rate of oocytes was significantly (p<0.05) higher in fraction 11 containing 18 kDa than other fractions. The present study suggests that 1) dbcAMP and Fo prevent the spontaneous maturation of oocyte after isolation from follicles, and that pEF contain a substance(s) that improves meiosis resumption in vitro of porcine COCs, 2) cationic 18 kDa protein(s) are responsible for promotion of Mil stage.

• 한국연초학회지
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• 제21권2호
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• pp.171-181
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• 1999

We examined the ultrastructure of eupyrene and apyrene spermatogenesis in the testis of Helicoverpa assulta (Lepidoptera: Noctuidae). The spermatogenesis was progressed near the fringe adjacent to the follicular layer of the testicular follicle, surrounding the apical cell concentrically. Eupyrene and apyrene were firstly distinguished at the telophase stage of the primary spermatocyte. Chromatin was evenly scattered in eupyrene nuclei, whereas it was lumped near the nuclear envelope in apyrene spermatogenesis. Then, the nucleus of eupyrene was transformed into two daughter nuclei by meiosis, while the nucleus of apyrene was divided into many micronuclei by irregular meiosis. After the meiosis was completed, a number of mitochondria in the cytoplasm of the early spermatids of the eupyrene and the apyrene were fused into one nebenkern. Also, as axial filament was formed due to the elongation of the spermatid, the nebenkern became splitted into mitochondrial derivatives. An acrosome precursor was present only in the eupyrene, attached to nuclear envelope.

• Clinical and Experimental Reproductive Medicine
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• 제38권2호
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• pp.68-74
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• 2011

Objective: Previously, we found that oocyte specific homeobox (Obox) 4 plays significant role in completion of meiosis specifically at meiosis I-meiosis II (MI-MII) transition. The purpose of this study was to determine the mechanism of action of $Obox4$ in oocyte maturation by evaluating downstream signal networking. Methods: The $Obox4$ dsRNA was prepared by $in$ $vitro$ transcription and microinjected into the cytoplasm of germinal vesicle oocytes followed by $in$ $vitro$ maturation in the presence or absence of 0.2 mM 3-isobutyl-1-metyl-xanthine. Total RNA was extracted from 200 oocytes of each group using a PicoPure RNA isolation kit then amplified two-rounds. The probe hybridization and data analysis were used by Affymetrix Gene-Chip$^{(R)}$ Mouse Genome 430 2.0 array and GenPlex 3.0 (ISTECH, Korea) software, respectively. Results: Total 424 genes were up (n=80) and down (n=344) regulated after $Obox4$ RNA interference (RNAi). Genes mainly related to metabolic pathways and mitogen-activated protein kinase (MAPK) signaling pathway was changed. Among the protein kinase C (PKC) isoforms, PKC-alpha, beta, gamma were down-regulated and especially the MAPK signaling pathway PKC-gamma was dramatically decreased by $Obox4$ RNAi. In the cell cycle pathway, we evaluated the expression of genes involved in regulation of chromosome separation, and found that these genes were down-regulated. It may cause the aberrant chromosome segregation during MI-MII transition. Conclusion: From the results of this study, it is concluded that $Obox4$ is important upstream regulator of the PKC and anaphase-promoting complex action for maintaining intact germinal vesicle.

• Animal Bioscience
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• 제37권1호
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• pp.50-60
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• 2024

Objective: Testicular fat deposition has been reported to affect animal reproduction. However, the underlying mechanism remains poorly understood. The present study explored whether sperm meiosis and testosterone synthesis contribute to mouse testicular fat deposition-induced reproductive performance. Methods: High fat diet (HFD)-induced obesity CD1 mice (DIO) were used as a testicular fat deposition model. The serum hormone test was performed by agent kit. The quality of sperm was assessed using a Sperm Class Analyzer. Testicular tissue morphology was analyzed by histochemical methods. The expression of spermatocyte marker molecules was monitored by an immuno-fluorescence microscope during meiosis. Analysis of the synthesis of testosterone was performed by real-time polymerase chain reaction and reagent kit. Results: It was found that there was a significant increase in body weight among DIO mice, however, the food intake showed no difference compared to control mice fed a normal diet (CTR). The number of offspring in DIO mice decreased, but there was no significant difference from the CTR group. The levels of follicle-stimulating hormone were lower in DIO mice and their luteinizing hormone levels were similar. The results showed a remarkable decrease in sperm density and motility among DIO mice. We also found that fat accumulation affected the meiosis process, mainly reflected in the cross-exchange of homologous chromosomes. In addition, overweight increased fat deposition in the testis and reduced the expression of testosterone synthesis-related enzymes, thereby affecting the synthesis and secretion of testosterone by testicular Leydig cells. Conclusion: Fat accumulation in the testes causes testicular cell dysfunction, which affects testosterone hormone synthesis and ultimately affects sperm formation.

• 미생물학회지
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• 제35권4호
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• pp.258-265
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• 1999

출아효모에서는 질소원의 고갈과 MATa/MAT${\alpha}$ 이배체 세포의 감수분열기 특이적인 유전자 발현에 의해 체세포분열기의 G1기에서 감수분열기로의 진행이 결정된다. 이러한 두 경로는 감수분열기 특이적인 IME 유전자군에 의한 전사조절에 의해 활성화되어 감수분열기가 시작된다. 본 연구는 IME2 유전자가 protein kinase 로서 감수분열기의 어떤 과정에 직접 관여하는가를 조사하기 위하여 먼저 PCR mutagenesis를 통하여 온도감수성 ime2 변이주를 분리하였다. 전체 62개의 온도감수성 변이주 중에서 온도에 따른 포자형성능과 감수분열기 재조합 빈도에 대하여 명확한 차이를 나타내는 3종류의 변이주들(ts ${\cdot}$ ime2-11, ts ${\cdot}$ ime2-12와 ts ${\cdot}$ ime2-13)을 선택하였다. 이러한 3종류의 온도감수성 변이주를 이용하여 제한온도에서 감수분열기 초기과정 중 결손을 조사하기 위해, FACScan analysis를 한 결과 IME2유전자가 감수분열기의 DNA 복제과정의 개시 및 완료에 관여함을 알 수 있었고, his4 혹은 arg4 locus에서 감수분열기 재조함 빈도의 측정으로 재조합 과정에 중요한 역할을 한다는 것을 알 수 있었다. 더욱이${\Delta}$mre4 파괴주에 IME2유전자를 과다발현시켜 그 영향을 조사한 결과, 감수분열기 특이적인 protein kinase 인 IME2와 MRE4가 감수분열기 초기과정인 재조합 과정에서는 동일한 경로에 작용한다는 것이 제시되었다.

• Nutrition Research and Practice
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• 제16권3호
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• pp.314-329
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• 2022

BACKGROUND/OBJECTIVES: Oocyte lipid droplets play a crucial role in meiosis and embryo development. Biotin is associated with fatty acid synthesis and is the coenzyme for acetyl-CoA carboxylase (ACC). The effects of a biotin deficiency on the oocyte lipid metabolism remain unknown. This study examined the effects of a biotin deficiency and its replenishment on murine 1) oocyte lipid droplet levels, 2) ovary lipid metabolism, and 3) oocyte meiosis. MATERIALS/METHODS: Mice were divided into 3 groups: control, biotin deficient (BD), and recovery groups. The control and BD groups were fed a control diet or BD diet (0.004 or 0 g biotin/kg), respectively. The recovery group mice were fed a BD diet until day 21, and were then fed the control diet from days 22 to 64. This study then quantified the oocyte lipid droplet levels, assessed the oocyte mitochondrial function, and examined the ability of oocytes to undergo meiosis. Ovarian phosphorylated ACC (p-ACC), lipogenesis, β-oxidation, and ATP production-related genes were evaluated. RESULTS: The BD group showed a decrease in lipid droplets and mitochondrial membrane potential and increased p-ACC levels. In the recovery group, the hepatic biotin concentration, ovarian p-ACC levels, and mitochondrial membrane potential were restored to the control group levels. On the other hand, the quantity of lipid droplets in the recovery group was not restored to the control levels. Furthermore, the percentage of oocytes with meiotic abnormalities was higher in the recovery group than in the control group. CONCLUSIONS: A biotin deficiency reduced the oocyte lipid droplet levels by downregulating lipogenesis. The decreased lipid droplets and increased oocyte meiosis failure were not fully restored, even though the biotin nutrition status and gene expression of lipid metabolism was resumed. These results suggest that a biotin deficiency remains robust and can be long-lasting. Biotin might play a crucial role in maintaining the oocyte quality.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권12호
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• pp.667-674
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• 2000

In this paper, a modified real-valued genetic algorithm is developed by using the meiosis for human's chromosome. Unlike common crossover methods adapted in the conventional genetic algorithms, our suggested modified real-valued genetic algorithm makes gametes by conducting the meiosis for individuals composed of chromosomes, and then generates a new individual through crossovers among those. Ultimately, when appling it for the gas data of Box-Jenkin, model and parameter identifications can be concurrently done to construct the optimal model of a neural network in terms of minimizing with the structure and the error.

• 한국자원식물학회지
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• 제1권1호
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• pp.80-87
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• 1988

Hybries which was made up by chromosome of L. longiflorum and L. x elegans, using root-tip individual which was obtained through ovary slice culture, and root-tip of these parents, with hoirugen staining, gimsa staining and Q-H staining inaccordance with the location and the existence of secondary construction which waslocating near short arm centromere of No, 1,2,6,9. In metaphase of meiosis ofhybrid which was made up by univalent from 2 individuals to 10 individuals wasobserved, and nuclear plate which was having abnormal type's synthesis amounted to91% of all cells whieh were observed. This result showed the fact that someobstacle arose annormal progress of the divission after that time. 63% of the cellshad micronucleus from 1 individlial to 4 individuals in tetrad phase of meiosisdivision. The peroxidase and $\alpha$ -estelase zymogram phenotypes of parents andhybrids were determined using agarlose IEF gel. Crosses were performed betweenparents bearing dissimilar allelomorphs in orther to discern the genetic control ofthe resolved enzymes. Genetic variation of hybrids were detected at all but 2 plant progenies.