To evaluate the effects of benzo[a]pyrene (B[a]P), one of polycyclic aromatic hydrocarbons (PAHs), on in vitro oocyte maturation (GVBD) and sex steroid hormone production, maturing oocytes (oocyte diameters=0.74, 0.88 and 0.93 mm) of the longchin goby, Chasmichthys dolichognathus were incubated with B[a]P (1, 10 and 100 ng/mL) for 24 hours. After incubation, the oocytes were fixed with clearing solution (ethanol:formalin:glacial acrtic acid=6:3:1). The location of the germinal vesicle was observed under low-power magnification using a dissecting microscope. Steroids in aliquots of the incubation media were extracted twice using five volumes of ethylacetate:cyclohexane (1:1). Then, the T, E2 and 17α20βP levels were measured by RIA. In oocytes 0.74 mm diameter (vitellogenic oocytes), B[a]P had no significant effect on GVBD at the concentrations tested. In oocytes 0.88 mm diameter (fully vitellogenic oocytes), B[a]P inhibited GVBD significantly at 1 and 100 ng/mL. T production was decreased and the ratio of E2/T was increased significantly at 1 and 10 ng/mL compared with control. In 0.93 mm diameter oocytes (germinal vesicle located near the center of oocytes), B[a]P induced GVBD significantly at 10 and 100 ng/mL and decreased the ratio of E2/T significantly at 1 and 10 ng/mL compared with control. These findings suggest that B[a]P has different sensitivity to the oocyte maturation according to the oocyte diameters.

Plants are known to have homeostatic cellular mechanisms to control the concentration of heavy metal inside the cell. We tried to retrieve rice RING finger protein genes, which are believed to regulate substrates via ubiqitinations, related to metal ions detoxification mechanisms. A total of 48 rice RING finger proteins were randomly selected and then examined for their expression patterns as exposed to cadmium and arsenic treatments. We discovered a RING finger protein gene that was significant up-regulated against both treatments and then named Oryza sativa heavy metal induced 1 (OsHMI1). We tested subsequently OsHMI1 expression patterns against to salinity, dehydration, cold, heat stress and phytohormones treatments. In addition, we evaluated its subcellular localization and determined E3 ligase activity. The interaction partner proteins were screened via yeast-two hybridization. These results might shed further light on the understanding of homeostatic cellular mechanisms to control heavy metal detoxification via protein degradation in plants.

We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol-17β (E2), 17,20 β-dihydroxy-4-pregnen-3-one (17α20βOHP), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The fish were collected at the coastal waters of Dadaepo, Busan, Korea from August 2002 to March 2003. Body weight, liver weight and gonad weight were measured for calculation of hepatosomatic index (HSI) and gonadosomatic index (GSI). Plasma steroid and cortisol levels were measured by radioimmunoassay and data were analyzed using the Kruskal-Wallis test and the Spearman rank correlation. The GSI of females increased from November, peaked in February (13.21±2.27) and decreased rapidly from March (1.05±0.23). The GSI of males also increased from November, peaked in December (0.36±0.12) and remained high to February. In females, E2 levels increased and remained high from December to February (19.81±7.46～22.85±6.18 ng/ ㎖). The levels of T showed a similar tendency and correlated (rs=0.813, p=0.0001) significantly with E2 levels. The levels of 17α20βOHP increased rapidly in February (4.78±1.01 ng/㎖) and peaked in July (5.08±0.65 ng/㎖). Cortisol level was peaked in March (2081.07±1140.02 ng/㎖) and correlated significantly with 17α20βOHP levels (rs=0.790, p=0.0001). In males, the levels of T was peaked in January (2.43±0.17 ng/㎖) and then decreased rapidly. The levels of 11KT were remained high from October to January (3.27±1.55～4.28±1.53 ng/㎖) and correlated significantly with T levels (rs=0.513, p=0.002). On the other hand, the levels of 17α20βOHP fluctuated during reproductive cycle and the variation pattern of cortisol levels were similar to females. These results suggest that plasma sex steroids in ribbed gunnels have annual periodicity, and that cortisol may involve in maturation of females.

This study is to survey the ultrastructure of gamete cells and micropyle of pre-fertilized and post-fertilized eggs after HCG hormone treatment by transmission and scanning electron microscopy (TEM and SEM) in E. akaara, E. bruneus and E. septemfasciatus. These fishes are economical importance species for Jeju coastal area resources. In spite of its an importance resources, details studies on the ultrastructural aspects of gamete cells for its reproductive biology have not been undertaken. Morphological features of ovulation process have been studied during its normal occurrence in the reproductive cycle of these fish by light microscopy. Moreover, it has been studied for many years to induce spawning by environmental factors (day length, water temperature etc) or injection of HCG for ovulation in these species. Studies on the micropyle was mainly focused on the eggs of insects, fresh water and a few sea water fishes. Micropylar structure of fish displays morphological characteristics of interspecies-specific by inhabitant environment and spawning feature. On the other hand, it is an importance cue for a taxonomical indicator and identification fish eggs. SEM studies were performed on growing and mature oocytes obtained by stripping and cannulation from 3 grouper species sampled between July and August in spawning season. The outer layer of chorion of preovulatory growing stage oocytes could be divided into four layers; zona pellucida, follicular cell layers consisted of granulosa and thecal cells layer and the most outer ovigerous lamella. Ovulation process of mature stage oocytes initiated by rupture of ovigerous lamella and ovulated by contraction of follicular cell layers. Besides, the micropylar shape of ripe stage oocytes in E. akaara, E. bruneus and E. septemfasciatus presented volcano or crateriform-like cylindrical form. Internal structure of micropylar vestibule displayed cylindrical clockwise 8 or 10 spiral arrangement structure in these species. The micropyle diameter and apparatus at the animal pole differ significantly among the 3 species. The difference in their diameters suggests species-specific in the correlation between spermatozoal head size and micropylar diameter for polyspermy prevention and hybridization during fertilization. Besides, after artificial fertilization, the vestibule morphologically transformed into dom-shape and pillar-shape for fertilization cone formation. Pores of various sizes in the 3 grouper species were somewhat regularly distributed in concentric circles only around the micropyle. In particular, large pores had numerous gill filament-shaped projections connected to oolemma. These structures are suggested to be related to gas exchange, osmoregulation, and micronutrient influx or efflux between eggs and water during fertilization and egg development. In addition, spermatozoa ultrastructure was examined in 3 grouper species. TEM investigation revealed that, in all species, spermatozoa display a round head, a nucleus containing highly condensed, filamentous chromatin clusters, no acrosome, a short midpieces consisting of numerous mitochondria and the proximal and distal centrioles and a flagellum exhibiting the typical axoneme structure (9+2). Especial, both E. akaara and E. bruneus display regular laternal fins in flagella, but in E. septemfasciatus, no fins in flagella with hook shape tails.

TILLING (Targeting Induced local Lesions IN Genomes) is known to be an excellent methodology for reverse genetics approach. About 15,000 M3 TILLING lines have been developed after gamma-ray irradiation to the rice seeds of Donganbye. In order to assess genetic diversity of the TILLING population. we have employed a multiple dominant marker technique, such as AFLP. A total of 96 (0.64%) lines including Dongganbye were randomly selected and their genetic diversity was assessed on the basis of AFLP marker polymorphism by using 5 primer combinations. An average of 100.4 loci with a range of 97 to 106 were detected by using the primer combinations, resulting in 173 (34.6%) polymorphic loci among 96 lines. A broad range of similarities with 80% to 96% was evidenced between Donganbye and each of 96 TILLING lines, reflecting genetic diversity of the TILLING population. About 30 polymorphic loci have been cloned and their sequences have been blasted against rice whole genome sequences. The sequences evidenced highly significant matches to each of genes including exons and introns, upstream sequences and downstream of genes, and intergeneic sequences. Therefore, the TILLING rice population would be valuable genetic sources for rice functional genomics.

All aspects of plant life are controlled by the regulated synthesis of new proteins and the precise degradation of preexisting proteins, predicting up to 50% of total plants protein is replaced every week. The ubiquitin/26S proteosome pathway is known to be one of mechanisms to regulate signal pathways, developmental process and abiotic/biotic stress responses via protein degradations. In the previous study, we have identified a large number of the RING ubiquitin ligase proteins whose functions have been clarified in the protein degradation pathway. Curiously, one RING-H2 finger protein gene evidenced striking differences in expression patterns in response to salt and dehydration stress between leaf and culm-node tissues. Characterization of the gene evidenced its function as E3 ubiquitin ligase activity by using an in vitro ubiquitination assay. We have constructed a library with rice culm-node tissues under salt stress for Yeast two hybrid assay and performed primary yeast two-hybrid screening with the gene as a bait. A total of 13 candidate genes were isolated as positive interacting partners. Gene ontology of most candidate genes appears to be related with various abiotic stresses. Therefore, the RING-H2 finger protein genes might function to regulate plant abiotic stress responses via protein degradation pathways.

The C3HC4 zinc RING finger proteins seem to be a family of protein-protein interactions. Little is information regarding the role of the C3HC4 zinc RING finger proteins in rice plant. We have attempted to assess their genome localization, phylogenetic relationship and expression patterns of members via in silico analysis as well as semi-quantitative RT-PCR. A total of 132 genes encoding C3HC4 zinc RING finger proteins appear to be distributed over 12 rice chromosomes, reflecting evolutionary dynamics of the rice genome, e.g. whole genome duplication and tandem duplications. A genome-wide dataset including 155 gene expression omnibus sample (GSM) plates evidenced a high degree of functional specialization of the rice C3HC4 zinc RING finger proteins, especially during developmental stages and against abiotic stresses. We have retrieved co-expression genes with each of the rice C3HC4 zinc RING finger proteins, probably providing some clues on specialized functions of individual genes. Expression patterns of 13 co-expression genes with one gene encoding C3HC4 zinc RING finger protein (Os04g51400) against salt and dehydration stresses were evaluated in crown tissues and leaf tissues, evidencing highly similar patterns among members. These findings might provide clues to shed further light on comprehensive functions of C3HC4 zinc RING finger proteins.

This study was carried out to compare the growth and yield characteristics between bakanae diseases (Gibberella fujikuroi) infected and normal rice plants. The infected rice seeds, harvested in last year, were disinfected by prochloraz for 48 hours at 33℃ using sprouting machine, 24 hours at room temperature and not disinfected. In the methods of disinfection, it is more effective in disinfected by prochloraz for 48 hours at 33℃ using sprouting machine near to 0% of infection rate, followed by conventional method as 5.0% and 76% in not disinfected rice seeds. In the rice yield components among the disinfection methods, panicles were increased about 11% in the disinfected seeds using sprouting machine for 48 hours compared to conventional method. Ripening grain rate also increased at the disinfected using sprouting machine as 80.3~80.3%, improved more than 4.9~5.9% comparing to the conventional disinfection. From these results, the rice yield was 512~517kg/1,000㎡ at the disinfected using sprouting machine which increased more than 6~7% compared to the conventional disinfection.

This study was conducted to identify the varietal differences of the viviparous germination and viviparous germinated seed characteristics occurred by continuous rain during maturing stage of rice in 2007. The viviparous germination rates were increased in early and medium-maturing cultivars such as Unkwangbyeo and Gopumbyeo. In the germinating rates using already viviparous germinated seeds were severely deteriorated by 15.3 and 28.2% compared to those of normal seeds as 97.3 and 98.5% on Unkwangbyeo and Gopumbyeo. The regermination rates were increased as the plumule length of already viviparous germinated seeds was shorter, so it is 46.7% in less than 0.9mm plumule length and 12.7% in 1.0~1.9mm.

The genetic diversity was evaluated using RAPD and ISSR among natural populations and Korean wheat cultivars (Triticum aestivum). Understanding the genetic diversity of putative parental and wild stocks would be useful in wheat breeding programs. Ninety three populations were evaluated with fifty RAPD and three ISSR primers. A total of 185 RAPD and ISSR polymorphism were produced. These markers were considered to estimate the genetic distance among accessions. The genetic similarity ranged from 0.41 to 0.86. The dendrogram were constructed by using the UPGMA clustering algorithm based on genetic similarity. The genetic diversity within and among accession was assessed through Principal Component Analysis (PCA) for statistics analysis. In cluster analysis, four groups were clustered and 17 accessions were not clustered. The PCA was corresponded well to the result. This study provides basic information about the genetic relationships for breeding purposes.