• 한국수산과학회지
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• 제50권2호
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• pp.219-221
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• 2017

In 2015, white cottony tufts were observed on gametophytes of the kelp Saccharina japonica. Wet mount and histopathology examination revealed numerous fungal hyphae and mycelium around the gametophytes. The gametophytes surrounded by fungal hyphae were generally round and empty. A specific 610-bp fragment of the internal transcribed spacer (ITS)-5.8S rDNA-ITS gene of fungi was amplified by polymerase chain reaction and the nucleotide sequence showed 100% identity with those of Acremonium sclerotigenum, Acremonium sp. and Ascomycota sp. When fungus-infected gametophytes were mixed with healthy gametophytes, a high transmission rate (100%) resulted. This is the first report of mycosis of gametophytes in Korea.

• Journal of Forest and Environmental Science
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• 제32권2호
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• pp.113-119
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• 2016

The long lived iteroparous conifers produce male and female gametophyte for hundreds of years once they reach the reproductive stage, however, the production of seed is not frequent. This phenomenon of infrequent seed production in conifers is yet to be understood. An attempt to study this change in cone production in Cedrus deodara of Western Himalayas -a species reported to be mainly monoecious and rarely dioecious has been made. The observations recorded on selected trees of flowering/fruiting stage for four years at four different locations have shown the species to be dioecious with higher percentage of female trees during good seed year but with no definite or predictable pattern of reproduction in the trees. A decline in production of female trees was witnessed at all but one location immediately year after reaching the maximum (good seed year). The phenomenon of seed production has been observed to be cyclic and site specific. A change in the sexual behavior of the trees from male to female or vice-versa, male or female turning monoecious or vegetative and vegetative coming to reproductive was unpredictable.

• 한국해양바이오학회지
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• 제12권2호
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• pp.115-122
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• 2020

Eisenia bicyclis, a perennial macroalga is a primary producer of in the ocean, It has been identified as a key species that plays a vital role in maintaining the ecosystem stability. Also, it is an important target in marine afforestation projects and useful marine organisms. In addition, E. bicyclis is used as a health food for humans. This study investigated the effect of water temperature, light (photon irradiance), and duration of light (photoperiod) on the growth of gametophytes and young sporophytes of E. bicyclis. The germination and growth of the zoospores of E. bicyclis were examined at five temperatures (5℃, 10℃, 15℃, 20℃ and 25℃), four intensities of photon irradiance (10, 20, 40, and 80 μmol m-2s-1), and photoperiods (14:10 and 10:14 light/dark cycles). The zoospores released from mature plant germinated into the gametophytes under all experimental conditions. The gametophytes were able to grow at water temperature 5℃-25℃ and mature at 10℃-20℃. The optimal range of water temperature for the maturation of the gametophyte was 15℃-20℃. At 25℃, E. bicyclis gametophytes grew rapidly but did not mature. The optimal culture conditions for the growth of young sporophytes grew slowly in low temperature and photon irradiances.

• Ocean and Polar Research
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• 제42권2호
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• pp.133-139
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• 2020

The aim of this study is to examine the physiological characteristics of an agarophyte Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N. Norris et Fredericq in the early life stage of tetrasporophytes (2n) and gametophytes (n) to select appropriate seedlings for mariculture. Growth experiments were carried out at the combinations of four temperatures (20, 25, 30, and 35℃) and three light intensity levels (20, 60, and 100 µmol photons m^-2 s^-1) in the two ontogenetic stages: discoid holdfasts and erect sporelings. Holdfast areas and sporeling lengths of tetrasporophytes and gametophytes were estimated after 14 days in culture. Relative growth rates (RGRs) for holdfast areas were 7.08-28.38% day^-1 for tetrasporophytes and 11.58-23.67% day^-1 for gametophytes. At 35℃, holdfasts of tetrasporophytes survived with RGRs of 7.08-23.28% day^-1 but those of gametophytes died. Maximal holdfast growth of tetrasporophytes occurred at 30℃ and 100 µmol photons m^-2 s^-1, which were different from gametophytes (25℃ and 100 µmol photons m^-2 s^-1). RGRs of tetrasporophytic sporelings were 2.93-11.11% day-1 and were between 0.78-10.82% day-1 for gametophytes. Maximal growth of A. vermiculophyllum sporelings occurred at 25℃ and 60 µmol photons m^-2 s^-1 for tetrasporophytes, and at 20℃ and 100 µmol photons m^-2 s^-1 for gametophytes. In conclusion, the present results indicate that carpospores could be used as resources of spore-seedling methods having genetic diversity for mass field cultivation because tetrasporophytes showed higher-temperature tolerance and faster-growing ability than gametophytes of A. vermiculophyllum in the discoid holdfast and sporeling stages.

• Molecules and Cells
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• 제43권5호
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• pp.448-458
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• 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.

• Ocean and Polar Research
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• 제37권3호
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• pp.201-209
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• 2015

To examine the effects of increased $CO_2$ concentration and seawater temperature on the photosynthesis and growth of forest forming Ecklonia cava (Laminariales, Phaeophyta), sporophytic discs and gametophytes were cultured under three $pCO_2$ concentrations (380, 750, 1000 ppm), four temperatures (5, 10, 15, $20^{\circ}C$ for sporophytes; 10, 15, 20, $25^{\circ}C$ for gametophytes), and two irradiance levels (40, $80{\mu}mol$ photons $m^{-2}s^{-1}$) for 5 days. Photosynthetic parameter values ($ETR_{max}$, $E_k$, and ${\alpha}$) were generally higher as sporophytic discs were grown under low temperature and increased $CO_2$ concentration at 750 ppm. However, photosynthesis of Ecklonia sporophytes was severely inhibited under a combination of high temperature ($20^{\circ}C$) and 1000 ppm $CO_2$ concentration at the two photon irradiance levels. The growth of gametophytes was maximal at the combination of 380 ppm (present seawater $CO_2$ concentration) and $25^{\circ}C$. Minimal growth of gametophytes occurred at enriched $pCO_2$ concentration levels (750, 1000 ppm) and high temperature of $25^{\circ}C$. The present results imply that climate change which is increasing seawater temperature and $pCO_2$ concentration might diminish Ecklonia cava kelp beds because of a reduction in recruitments caused by the growth inhibition of gametophytes at high $pCO_2$ concentration. In addition, the effects of increased temperature and $pCO_2$ concentration were different between generations - revealing an enhancement in the photosynthesis of sporophytes and a reduction in the growth of gametophytes.

• Parasites, Hosts and Diseases
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• 제51권2호
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• pp.147-154
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• 2013

To control coccidiosis without using prophylactic medications, a DNA vaccine targeting the gametophyte antigen Gam56 from Eimeria maxima in chickens was constructed, and the immunogenicity and protective effects were evaluated. The ORF of Gam56 gene was cloned into an eukaryotic expression vector pcDNA3.1(zeo)+. Expression of Gam56 protein in COS-7 cells transfected with recombinant plasmid pcDNA-Gam56 was confirmed by indirect immunofluorescence assay. The DNA vaccine was injected intramuscularly to yellow feathered broilers of 1-week old at 3 dosages (25, 50, and $100{\mu}g/chick$). Injection was repeated once 1 week later. One week after the second injection, birds were challenged orally with $5{\times}10^4$ sporulated oocysts of E. maxima, then weighed and killed at day 8 post challenge. Blood samples were collected and examined for specific peripheral blood lymphocyte proliferation activity and serum antibody levels. Compared with control groups, the administration of pcDNA-Gam56 vaccine markedly increased the lymphocyte proliferation activity (P<0.05) at day 7 and 14 after the first immunization. The level of lymphocyte proliferation started to decrease on day 21 after the first immunization. A similar trend was seen in specific antibody levels. Among the 3 pcDNA-Gam56 immunized groups, the median dosage group displayed the highest lymphocyte proliferation and antibody levels (P<0.05). The median dosage group had the greatest relative body weight gain (89.7%), and the greatest oocyst shedding reduction (53.7%). These results indicate that median dosage of DNA vaccine had good immunogenicity and immune protection effects, and may be used in field applications for coccidiosis control.

• Journal of Plant Biotechnology
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• 제44권3호
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• pp.287-295
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• 2017

Water temperature is one of the major factors that impacts the growth and life cycle of Pyropia tenera, one of the most valuable and cultivated marine red algae belonging to Bangiales (Rhodophytes). We analyzed transcriptome from gametophyte of P. tenera under normal and high temperature conditions, and identified four small heat shock proteins (sHSPs). They have no significant amino acid sequence homology with known proteins in public databases except PhsHSP22 from Pyropia haitanensis. PtsHSP19.3 gene responded to high temperature but slightly or not to desiccation, freezing or high salt condition. When the PtsHSP19.3 gene was overexpressed in Chlamydomonas reinhardtii, transformed Chlamydomonas lines revealed much higher growth rate than that of control cells under heat stress condition. Transformed cells also grew well in those of the control cell onto the medium containing high salt or $H_2O_2$. When the PtsHSP19.3 was fused to GFP and introduced into tobacco protoplast, fluorescence was detected at several spots. Results indicate that PtsHSP19.3 may form super-molecular assembles and be involved in tolerance to heat stress.

• 한국산림과학회지
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• 제3권1호
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• pp.1-4
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• 1963

개나리 단주화개체(短柱花個體)를 사용(使用)하여 자성배우체발육(雌性配偶體發育)의 지연(遲延) 및 이상(異常), 임성(稔性)과의 관계(關係)를 조사(調査)한바 그 결과(結果)를 요약(要略)하면 다음과 같다. 1. 도생배주(倒生胚珠)의 주피(珠皮)는 대단(大端)히 두텁고 주심(珠心)은 반대(反對)로 극(極)히 작다. 2. 소포자모세포(小胞子母細胞)의 감수분열(減數分裂)은 9월하순(月下旬)~10월초순경(月初旬頃)인데 대포자모세포(大胞子母細胞)는 3월중하순경(月中下旬頃)에야 일어 난다. 3. 대포자모세포기(大胞子母細胞期)는 대단(大端)히 길다. 4. 성열배낭(成熱胚囊)은 개화약(開花約) 1개월후(個月後)인 5월초(月初)에 형성(形成)된다. 5. 정상배낭(正常胚囊)은 많지 않고 대부분(大部分)의 경우 배낭(胚囊)이 없는 공허(空虛)한 주심조직(珠心組織)만 생(生)긴다.

• Journal of Plant Biology
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• 제37권1호
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• pp.43-51
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• 1994

고사리삼목, 고사리삼과에 속하는 2속 14종과 이들과의 비교를 위하여 마라티아목(Marattiales)의 Angiopteris 1종 및 고비목의 고비속(Osmunda) 3종 등 18종류의 포자의 극면의 형태를 비교한 결과 고사리삼속(Botrychium) 식물은 둥근 삼각형 또는 변이 오목한 둥근 삼각형으로, 나도고사리삼속(Ophioglossum)과 Angioptris 및 고비속은 원형으로 나타났다. 고사리삼속은 표벽의 미세 무늬에 따라 세 군으로 유집이 가능하였으며 이는 기존의 분류체계와 잘 일치하였다. 표벽의 미세 형태는 고사리삼속에 있어 아속간에 뚜렷한 차이를 보이나 이러한 차이가 나도고사리삼속이나 Angiopteris 혹은 고비속과의 차이보다 적은 것으로 나타나서 고사리삼속내 분류는 Clausen(1938)의 견해를 지지하고 있었다. 나도고사리삼속은 극면의 형태가 구형이며 추문상 혹은 유공상의 표벽무늬를 가져 한 군으로 뚜렷히 구분되었다. 그러나 속내에서는 포자의 특징으로 유집이 불가능하였으며 따라서 Clausen(1938)이나 kato(1987)의 견해를 지지하고 있었다. 아울러 조사된 11종류에 대한 포자 형태의 기재와 검색표를 제시하였다.