• Fisheries and Aquatic Sciences
• /
• v.12 no.1
• /
• pp.44-48
• /
• 2009

Nucleotide sequences of about 500 bp from the 5' end of mitochondrial (mt) DNA Cytochrome Oxidase I (COI) were analyzed to estimate the genetic variation between wild and cultured populations of the ascidian Halocynthia roretzi from two sites along the coast of Korea. A total of 25 haplotypes were defined by 21 variable nucleotide sites in the examined COI region. Genetic diversity (haplotype diversity and nucleotide divergence) of wild populations was higher than that of the cultured population. These data suggest that reduced genetic variation in the cultured population may have results from bottleneck effect caused by the use of a limited number of parental stock and pooling of gametes for fertilization. Pairwise population $F_{ST}$ estimates inferred that wild and cultured populations were genetically distinct. The combined results suggest that sequence polymorphism in the COI region would be preferable for estimating the genetic diversity of ascidian populations.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.165-167
• /
• 1994

This paper presents a new method for multiobjective optimization using Genetic Algorithm-Sexual Reproduction Model(SR model). In SR model, each individual consists of chromosome pairs. Sex cells(gametes) are produced through artificial meiosis in which crossover and mutation occur, The proposed method has two selection operators, one, individual selection which selects the individual to fertilize, and the other, gamete selection which makes zygote for offspring production, The two selection schemes are repectively conducted according to different fitness(or objective) function and consequently give a solution which is unbiased to any objectives. We apply the proposed method to optimization of the design parameters of Linear Induction Motor(LIM) and show its effectiveness.

• Mycobiology
• /
• v.39 no.4
• /
• pp.235-242
• /
• 2011

In contrast to the nuclear genome, the mitochondrial genome does not follow Mendelian laws of inheritance. The nuclear genome of meiotic progeny comes from the recombination of both parental genomes, whereas the meiotic progeny could inherit mitochondria from one, the other, or both parents. In fact, one fascinating phenomenon is that mitochondrial DNA in the majority of eukaryotes is inherited from only one particular parent. Typically, such unidirectional and uniparental inheritance of mitochondrial DNA can be explained by the size of the gametes involved in mating, with the larger gamete contributing towards mitochondrial DNA inheritance. However, in the human fungal pathogen Cryptococcus neoformans, bisexual mating involves the fusion of two isogamous cells of mating type (MAT) a and MAT${\alpha}$, yet the mitochondrial DNA is inherited predominantly from the MATa parent. Although the exact mechanism underlying such uniparental mitochondrial inheritance in this fungus is still unclear, various hypotheses have been proposed. Elucidating the mechanism of mitochondrial inheritance in this clinically important and genetically amenable eukaryotic microbe will yield insights into general mechanisms that are likely conserved in higher eukaryotes. In this review, we highlight studies on Cryptococcus mitochondrial inheritance and point out some important questions that need to be addressed in the future.

• ALGAE
• /
• v.36 no.2
• /
• pp.147-154
• /
• 2021

Kelp life history pathways alternate between macroscopic sporophytes that produce spores and microscopic gametophytes that produce gametes. Occasionally, an alternative pathway is seen. This study examined the circumstances by which the high latitude estuarine bull kelp, Nereocystis luetkeana, foregoes the "free-living microscopic stages by releasing embryonic sporophytes directly from sori. Sori were collected from adult N. luetkeana sporophytes from eight locations within Kachemak Bay, Alaska in 2018 and 2020 to examine spatial and temporal development of embryonic sporophytes on sori. Distinctions were made between sori collected from first-generation and overwintered adults to assess the influence of parental age on embryonic sporophyte release. Further distinctions were made between sori collected from attached and drifting individuals to assess the influence of the status of parental attachment to substrate on embryonic sporophyte release. Inspection of propagules released from sori after 48-h incubations indicated that embryonic sporophytes were occasionally released alongside viable spores. Though embryonic sporophytes were released from sori as early as spring, it was not evident that they were bound by seasonal or spatial limits. The percent of propagules that were embryonic sporophytes ranged from 0% to 100% but were not significantly different between first-generation and overwintered adults, nor were they different between attached and drifting individuals. Nevertheless, the characteristic of directly releasing embryonic sporophytes from adult sporophytes might have ecological advantages for N. luetkeana.

• Molecules and Cells
• /
• v.43 no.5
• /
• pp.448-458
• /
• 2020

T-DNA insertional mutations in Arabidopsis genes have conferred huge benefits to the research community, greatly facilitating gene function analyses. However, the insertion process can cause chromosomal rearrangements. Here, we show an example of a likely rearrangement following T-DNA insertion in the Anti-Silencing Function 1B (ASF1B) gene locus on Arabidopsis chromosome 5, so that the phenotype was not relevant to the gene of interest, ASF1B. ASF1 is a histone H3/H4 chaperone involved in chromatin remodeling in the sporophyte and during reproduction. Plants that were homozygous for mutant alleles asf1a or asf1b were developmentally normal. However, following self-fertilization of double heterozygotes (ASF1A/asf1a ASF1B/asf1b, hereafter AaBb), defects were visible in both male and female gametes. Half of the AaBb and aaBb ovules displayed arrested embryo sacs with functional megaspore identity. Similarly, half of the AaBb and aaBb pollen grains showed centromere defects, resulting in pollen abortion at the bi-cellular stage of the male gametophyte. However, inheritance of the mutant allele in a given gamete did not solely determine the abortion phenotype. Introducing functional ASF1B failed to rescue the AaBb- and aaBb-mediated abortion, suggesting that heterozygosity in the ASF1B gene causes gametophytic defects, rather than the loss of ASF1. The presence of reproductive defects in heterozygous mutants but not in homozygotes, and the characteristic all-or-nothing pollen viability within tetrads, were both indicative of commonly-observed T-DNA-mediated translocation activity for this allele. Our observations reinforce the importance of complementation tests in assigning gene function using reverse genetics.

• ALGAE
• /
• v.26 no.1
• /
• pp.21-32
• /
• 2011

Studies of the red algal genus Bostrychia over the last 15 years have made it a model system for many evolutionary processes within red algal species. The combination of newly developed, or first employed methods, in red algal species studies has made Bostrychia a pioneer genus in intraspecific studies. Bostrychia was the first genus in which a mitochondrial marker was used for intraspecific red algal phylogeny, and the first for which a 3-genome phylogeny was undertaken. The genus was the first red alga used to genetically show maternal plastid and mitochondria inheritance, and also to show correlation between cryptic species (genetically divergent intraspecific lineages) and reproductive incompatibility. The chemotaxonomic use, and physiological function of osmolytes, has also been extensively studied in Bostrychia. Our continuous studies of Bostrychia also highlight important aspects in algal species studies. Our worldwide sampling, and resampling in certain areas, show that intensive sampling is needed to accurately assess the genetic diversity and therefore phylogeographic history of algal species, with increased sampling altering evolutionary hypotheses. Our studies have also shown that long-term morphological character stability (stasis) and character convergence can only be correctly assessed with wide geographic sampling of morphological species. While reproductive incompatibility of divergent lineages supports the biological species nature of these lineages, reproductive incompatibility is also seen between isolates with little genetic divergence. It seems that reproductive incompatibility may evolve quickly in red algae and the unique early stages of fertilization (e.g., gametes covered by walls, active movement of spermatium nuclei to the distant egg nucleus), also well investigated in Bostrychia,. may be key to our understanding of this process.

• Development and Reproduction
• /
• v.24 no.1
• /
• pp.19-30
• /
• 2020

The pH of water is one of the main environmental factors exerting selective pressure on marine and freshwater organisms. Here, we focus on the influence of pH on an organism's ability to maintain homeostasis and investigate the effects of acidification on immunity-related genes and osmotic pressure during early development of the olive flounder, Paralichthys olivaceus. The aim of our study was to determine the influence of various pH levels on the fertilized eggs and larvae of P. olivaceus. Gametes of P. olivaceus were artificially introduced and the resulting fertilized eggs were incubated at pH 4.0 (low), 6.0, and 8.0 (equivalent to natural sea water; control). We found that all eggs sank from the water column at pH 4.0. After 38 h, these eggs showed slow development. Hatching occurred more slowly at pH 4.0 and 6.0 and did not occur at all at pH 4.0. Result of gene expression, caspase and galectin-1 were expressed from the blastula to pre-hatch stages, with the exception of the two-cell stage. HSP 70 was also steadily expressed at all pH levels over the five days. The osmolality of fertilized eggs differed marginally at each stage and across pH levels. So, this results demonstrates that low pH level is detrimental to P. olivaceus fertilized eggs.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.97-97
• /
• 2003

For many animals the centrosome consists of a pair of centrioles and surrounding pericentriolar materials (PCMs). PCMs have been known to play roles during cell division. It is known that centrioles are necessary to assemble centrosomal components. However, many types of oocytes undergo meiosis without centrioles. It is known that in nonmurine mammalian species, the sperm introduces an intact proximal centriole unlike sea urchin where two centrioles are introduced. In case of mouse sperm, the presence of centrosome is not clear In this study, a monoclonal antibody was developed to investigate centrosome during mouse germ cell and early embryo development. Results of immunostaining and Western blotting in CHO cells suggest that the monoclonal antibody recognizes a nuclear and centrosomal protein, thus called NCP. The NCP monoclonal antibody was used to screen a cDNA expression library prepared from 12.5 mouse brain to isolate NCP gene. Nucleotide size of NCP gene obtained from immunoscreening was about 5.5kb. It is determined that the NCP may be closely related with pericentriolar material -1 gene (Pcm-1) from the result of sequencing analysis. The molecular weight, 66kDa, calculated by known DNA sequence in database is consistent with that of detected from Western blotting using CHO cell lysates. Therefore, it is assumed that NCP may be alternative splicing form of Pcm-1 of which molecular weight is 228kDa. In mouse oocytes, NCP was distributed in nucleus as in CHO cells. It was shown that the NCP was localized around neck region, probably the centrosome in mouse neck region. Interestingly, dramatic change in distribution of NCP was also shown in male germ cell development. Finally, we observed the cellular distribution of NCP during early embryo development. NCP was detected in nucleus as well as centrosome foci. It is suggested that the centrioles reassembly we occurring in blastocysts and then affects the distribution of NCP.

• Environmental Analysis Health and Toxicology
• /
• v.25 no.1
• /
• pp.11-18
• /
• 2010

Toxicity assessment of ocean dumping wastes (dye waste, urban sewage, food waste) were examined in the fertilization and embryo development rates of the Sea Urchin, Hemicentrotus pulcherrimus. Spawning was induced by injecting 1 mL of 0.5 M KCl into coelomic cavity. Males released white or cream-colored sperms and females released yellow or orange-colored eggs. Experiments were began within 30 min the collection of both gametes. The fertilization and embryo development rates test were performed for 10 min and 64 h after fertilization, respectively. The fertilization and embryo development rates in the control condition (not including ocean dumping wastes sludge elutriate) were greater than 90%, but suddenly decreased with increasing of ocean dumping waste sludge elutriate concentrations. The fertilization and normal embryogenesis rates were significantly inhibited in all waste sludge elutriate from dye waste ($EC_{50}$=4.37; $EC_{50}$=1.76), urban sewage ($EC_{50}$=5.79; $EC_{50}$=2.00) and food waste ($EC_{50}$=7.68; $EC_{50}$=2.16), respectively. The NOEC (<3.13) and LOEC (3.13) of fertiliztion and normal embryogenesis rates very similar in all waste sludge elutriate. These results suggest that biological assay using the fertilization and embryo development rates of H. pulcherrimus are very useful test method for the ecological toxicity assessment of ocean dumping wastes.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.1
• /
• pp.17-24
• /
• 2012

We cloned and sequenced the cDNA encoding the $FSH{\beta}$ and $LH{\beta}$ subunits from the pituitary of the blacktip grouper Epinephelus fasciatus, which regulate vitellogenesis and maturation in vertebrates, to achieve stable and healthy gametes. The full-length cDNAs of $FSH{\beta}$ and $LH{\beta}$ were 571 bp and 617 bp, encoding 120 amino acid (aa) and 147 aa proteins, respectively. The deduced amino acid sequences of $FSH{\beta}$ and $LH{\beta}$ were highly homologous (68-97%) to those of other Perciformes; E. bruneus, Dicentrarchus labrax, Thunnus thynnus, and Pseudolabrus sieboldi. Phylogenetic analysis showed that the deduced $FSH{\beta}$ and $LH{\beta}$ amino acid sequences were categorized as a distinct subunit in the $GTH{\beta}$ family, and are closely related to the teleostei $FSH{\beta}$ and $LH{\beta}$, respectively. $FSH{\beta}$ and $LH{\beta}$ mRNA exhibited high abundance in the pituitary gland and low in other brain areas, but were not present in peripheral tissues, as determined by RT-PCR.