• Korean Journal of Plant Tissue Culture
• /
• v.27 no.5
• /
• pp.411-413
• /
• 2000

The ability of microspores or young pollen grains (male gametophytes) to undergo developmetal switch to embryogenic (sporophytic) pathway exemplifies the concept of totipotency as applied to haploid posmeiotic cells. As a first step pollen is devoid of positional information provided in situ by the intact anther - by isolation and cultivation in vitro in artificial media. This is inevitably accompanied by some degree of stress response in microspore/pollen. It has been shown in both monocots and dicots that intentional stress treatment (mostly starvation or heat shock) greatly stimulates embryo induction rate. Using transgenic sHSP antisense Nicotiana tabacum we show that expression of small heat shock proteins is an integral part of successful embryo and later haploid plant production from pollen grains. Our recently published data show that sHSP chaperone function is optimal in the absence of ATP.

• The Korean Journal of Malacology
• /
• v.9 no.2
• /
• pp.30-43
• /
• 1993

The number of chronosomes and karyotypes in eight species of the family Bradybaenidae were analyzed by air-drying method using gonad. The mitotic haploid chromosome numbers of Acusta despecta sieboldiana were 29 and conisisted of 12 pairs metacentric, 17 pairs submetacentric chromosomes. The mitotic haploid chromosomes were 29 and 11 pairs metacentric and 17 pairs submetacentric and 1 pair telocentric chromosomes in Koreanohadra kurodana; 29 and 10 pairs metacentric chromosomes in K. koreana' 29 and 10 pairs metacentric and 18 pairs submetacentric, and 1 pair acrocentric chromosomes in Karaftohelix adamsi; 28and 10 pairs metacentric, and 18 pairs submetacintric chromosomes in Aegista chosenica; 28 and 14 pairs metacentric and 14 pairs submetacentric chromosomes in A.(Plectotropis) diversa; 28 and 15 pairs metacentric, 10 pairs submetacentric and 3 pairs acrocentric chromosomes in A. (p.)quelpartinsis; 29 and 12 pairs metacentric and 9 pairs submetacentric and 2 pairs telocentric chromosomes in Nesiohelix samarangae.

• Microbiology and Biotechnology Letters
• /
• v.22 no.6
• /
• pp.584-592
• /
• 1994

Several mutation procedures have been compared to obtain an ethanol-tolerant Saccha- romyces diastaticus strain secreting glucoamylase. These procedures include spontaneous mutation, EMS treatment, UV irradiation, and combination of EMS treatment and UV irradiation. All these methods were followed by adaptation of the yeast cells to gradually higher ethanol concentration. Among these procedures, the combined method of EMS treatment and UV irradiation gave the promising result, i.e. the ethanol tolerance of the yeast increased from 11.5%(v/v) to 14.0%(v/v). Respiratory deficient petite mutants of industrial and ethanol-tolerant yeast strains have been isola- ted and hybridized with haploid S. diastaticus strains. The resulting hybrids showed increased ethanol tolerance and starch-fermentability.

• Journal of the Korean Society of Tobacco Science
• /
• v.15 no.2
• /
• pp.137-144
• /
• 1993

The present study was conducted to compare the efficiency of individual plant selection for resistance to bacterial wilt with 30 dihaploid lines derived by anther culture and Nicotiana africana method in Fl and F2 generation from a cross between Bright Yellow 4 (BY4) and NC95. F2 dihaploid lines were selected from bacterial wilt disease resistant plants screened under the naturally infested filed conditions. The populations of FB - ADH and FB MDH derived from F2 individual plants with bacterial wilt resistance showed higher resistance to the disease than the populations of Fl - ADH and Fl - MDH, respectively, and no difference for the disease resistance appeared by the haploid deriving method within a generation.

• Microbiology and Biotechnology Letters
• /
• v.14 no.4
• /
• pp.299-304
• /
• 1986

The cell volume, cell surface, cell concentration, dry cell weight, frequence of respiratory deficient mutation, resistance against ultraviolet irradiation, fermentation power, DNA contents of haploid diploid, triploid and tetraploid of Saccharomyces cerevisiae strain were investigated. Respiratory deficient mutants by spontaneous mutation were absolved more frequently in the haploid than in the diploid, triploid and tetraploid. And cell volume, cell surface, cell concentration, dry cell weight, resistance against ultraviolet irradiation, fermentation power, and DNA contents were significantly increased as the ploidy increased.

• Microbiology and Biotechnology Letters
• /
• v.13 no.2
• /
• pp.129-135
• /
• 1985

The amylolytic yeasts were isolated from natural sources. Among them, a strain FRI YO-32 was selected as one of the genetically potential microorganisms and was identified as a strain of Hansenula anomala var anomala. Genetic markers were introduced into the isolated haploid strains of the strain FRI YO-32 and Saccharomyces cerevisiae by conventional mutagenic procedures with EMS or MNNG.

• Genomics & Informatics
• /
• v.6 no.3
• /
• pp.130-135
• /
• 2008

The haplotypes of a 200 kb region in the human chromosome X terminal band (q28) were analyzed using the International HapMap Project Phasell data, which had been collected for three analysis panels (YRI, CEU, and CHB＋JPT). When multiple linkage disequilibrium blocks were encountered for a panel, the neighboring haplotypes that had crossover rate of 5% or more in the panel were combined to generate 'haploid' configurations. This resulted in 8, 7, and 5 'haploid' configurations for the panels of YRI, CEU, and CHB＋JPT, respectively. The multiple sequence alignment of these 'haploids' was used for the calculation of allele-sharing distances and the subsequent principal coordinate analysis. Two 'haploids' in CEU and CHB＋JPT were hypothesized as 'parental' in light of the observations that the successive recombinants of these haploids can model two other haploids in CEU and CHB＋JPT, and that their configurations were consistent with those in YRI. This study demonstrates the utility of haplotype phylogeny in understanding population evolution.

• Journal of Plant Biology
• /
• v.36 no.1
• /
• pp.105-112
• /
• 1993

Selection of glyphosate-resistant clones from MNNG-treated mesophyll protoplasts of haploid tobacco and their differentiation were studied. The protoplasts were treated with 0.1 to 100 $\mu\textrm{g}$/mL N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for 30 min when they expanded to oval shapes. After the treatment, the protoplasts in 4-16 cell stages were transferred to the selective medium containing 1 mM glyphosate for the selection of the glyphosate-resistant colonies. The efficiency of the cell division of the protoplasts in the selective medium decreased as the MNNG concentrations in creased. Optimal MNNG concentration for induction of the glyphosate-resistant clones was 10$\mu\textrm{g}$/mL and mutation frequency was 2.66$\times$10-6. The stability of the glypohsate-resistance of the clones was examined by prolonged subculture in the medium with 1 mM glyphosate, and the resistant clones were survived more than 10 months. Among them one clone has been proliferating and greening and the others were proliferating without greening or greening with slower proliferating.

• Journal of the Korean Society of Tobacco Science
• /
• v.16 no.1
• /
• pp.64-68
• /
• 1994

The present experiments were conducted to investigate some of the factors affecting the number of haploids derived from anther culture of Nicotiana tabacum. Anther - donor plants grown under controlled environment room at 3$0^{\circ}C$ yielded more haploid than room at 18, 25 and 26-22-18$^{\circ}C$ in anther culture. Donor plants starved of fertilizer yielded more haploids as compared to those of the well fed with fertilizer in anther culture. Pretreatment of exercised flower bud at 5$^{\circ}C$ was shown to be more effective in anther culture than pretreatment at 7 and 1$0^{\circ}C$, and the optimum temperature and period of pretreatment were 4 or 6 days at 5$^{\circ}C$.

• Journal of Animal Reproduction and Biotechnology
• /
• v.37 no.4
• /
• pp.213-217
• /
• 2022

Haploidization in somatic cells is the process of reducing the diploid somatic chromosomes to haploid. Several studies have attempted somatic haploidization using oocytes in mice and humans. Some researchers showed partial somatic haploidization, but none observed embryo development. Our study attempted somatic haploidization using the modified somatic nuclear transfer (SCNT) protocol with various combinations of chemicals or proteins in mice. This study induced the proper segregation of somatic homologous chromosomes and full embryo development in vitro. Furthermore, somatic haploid embryos established embryonic stem cells and produced live births. The current review summarizes this recent study on the success of somatic haploidization and provides an overview of other related studies on somatic haploidization.