• Korean journal of applied entomology
• /
• v.40 no.2
• /
• pp.117-123
• /
• 2001

The occurrence and damage by the oriental fruit moth, Grapholita molesta (Busck) were investigated on pear trees from 1996 to 2000 in the Naju, Korea. The number of overwintering larvae in pear trees considerably varied depending on the maturation time of varieties. The density of overwintering larvae on late cultivars such as Gamcheonbae and Okusankichi was high, but relatively low on early cultivars. Trunk and main branch of pear trees were main overwintering sites. In 1997, overwintering larvae began to pupate from middle February, and to emerge from late March. Male moths were caught in the sex pheromone traps from late March until early October with four peaks of flight in 1996~2000. In every generation larvae damaged both the shoots and fruits of pear tree, but the first and second generation larvae tended to damage mainly shoots, while most of the injured fruits were due to the third and fourth generation larvae. In pear fruits damaged by fruit moths, most of these were caused by oriental fruit moth larvae and none of pear fruits were damaged by peach fruit moth or pear fruit moth larvae in 1998~2000.

• Fisheries and Aquatic Sciences
• /
• v.14 no.4
• /
• pp.379-388
• /
• 2011

The mechanism by which gonadotropin-releasing hormone (GnRH) and dopamine (DA) control gonadotropin (GTH) release was studied in male and female rainbow trout using cultured pituitary cells obtained at different reproductive stages. The mechanisms of follicle-stimulating hormone (FSH) release by GnRH and DA could not be determined yet. However, basal and salmon-type GnRH (sGnRH)- or chicken-II-type GnRH (cGnRH-II)- induced luteinizing hormone (LH) release increased with gonadal maturation in both sexes. LH release activity was higher after sGnRH stimulation than cGnRH-II stimulation at maturing stages in both sexes. The GnRH antagonist ([Ac-3, 4-dehydro-$Pro^1$, D-p-F-$Phe^2$, D-$Trp^{3,6}$] GnRH) suppressed LH release by sGnRH stimulation in a dose-dependent manner, although the effect was weak in maturing fish. The role of DA as a GTH-release inhibitory factor differs during the reproductive cycle: the inhibition of sGnRH-stimulated LH release by DA was stronger in immature fish than in maturing, ovulating, or spermiated fish. DA did not completely inhibit sGnRH-stimulated LH release, and DA alone did not alter basal LH release. Relatively high doses ($10^{-6}$ or $10^{-5}M$) of domperidone (DOM, a DA D2 antagonist) increased LH release, which did not change with reproductive stage in either sex. The potency of DOM to enhance sGnRH-stimulated LH release was higher in maturing and ovulated fish than in immature fish. These data suggest that LH release from the pituitary gland is controlled by dual neuroendocrine mechanisms by GnRH and DA in rainbow trout, as has been reported in other teleosts. The mechanism of control of FSH release, however, remains unknown.

• Development and Reproduction
• /
• v.20 no.4
• /
• pp.305-314
• /
• 2016

The marine medaka, Oryzias dancena is a suitable sample as a laboratory animal because it has a small size and clearly distinguishes between female and male. Data on the growth and maturity of the diploid and triploid sea cucurbit species suitable for laboratory animals are very useful for studying other species. Triploidy was induced in the marine medaka by cold shock treatment ($0^{\circ}C$) of fertilized eggs for 45 min, applied two minutes after fertilization. The diploid and triploid male fish were larger than their female counterparts (P<0.05), and the concentrations of thyroid stimulating hormone (TSH) and thyroxine (T4) were higher in the induced triploids over 1 year (P<0.05). In both the diploid and tri-ploid groups the concentrations of TSH and T4 were higher in the male fish than in the females (P<0.05), while the testo-sterone and estradiol-$17{\beta}$ concentrations in the induced triploids were lower than in the diploids (P<0.05). The gonadosomatic index (GSI) of the triploid fish was lower than that for the diploids, and the GSI for females in each ploidy group were higher than that for the males. For both groups the GSI was highest at 4 months of age, and decreased thereafter to 12 months. Analysis of the gonads of one-year-old triploid fish suggested that the induction of triploidy probably causes sterility in this species; this effect was more apparent in females than in males.

• Development and Reproduction
• /
• v.18 no.4
• /
• pp.293-300
• /
• 2014

Direct cell-cell communication through connexin (Cx) complexes is a way to achieve functional accordance of cells within a tissue or an organ. The initial segment (IS), a part of the epididymis, plays important roles in sperm maturation. Steroid hormones influence on expression of a number of genes in the IS of adult animals. However, developmental effect of sex hormones on the gene expression in the IS has not been examined. In this study, estradiol benzoate (EB, an estrogen agonist) or flutamide (Flu, an androgen antagonist) was exogenously administrated at 1 week of postnatal age, and expressional changes of Cx genes in the IS were determined at 4 months of age by a quantitative real-time PCR analysis. Treatment of EB at $0.015{\mu}g/kg$ body weight (BW) increased expression of Cx30.3, 31.1, and 43 genes. However, treatment of 1.5 mg EB/kg BW resulted in expressional decreases of Cx31, 32, and 45 genes and caused increases of Cx30.3 and 43 gene expression. Significant decreases of Cx31, 31.1, 32, 37, and 45 gene expression were detected with a treatment of $500{\mu}g\;Flu/kg$ BW, while expression of Cx43 gene was significantly increased with a treatment of $500{\mu}g\;Flu/kg$ BW. A treatment of $50{\mu}g\;Flu/kg$ BW led to significant increases of Cx30.3, 32, 37, 40, and 43 gene expression. These findings imply that exogenous exposure of steroidal hormones during the early developmental period would result in aberrant expression of Cx genes in the adult IS.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.39 no.5
• /
• pp.410-418
• /
• 2006

Sexual maturity and growth characteristics of Octopus minor were investigated in 796 individuals from mud flats in Goorori, Muan-Goon, Korea. Gonadosomatic index (GSI) peaked between June and July in females and between November and January in males. The discrepancy in the index peaks between females and males might result from the earlier sexual maturation of males. The sex ratio was biased toward females (68%) in April and toward males (78%) in September, although the differences were not significant (p>0.05). In females, about 50% of individuals with a mantle length of 70.6 mm were sexually mature versus 100% of individuals with mantle lengths over 80 mm. In females, fecundity was also related to size, ranging from 44 eggs in individuals with a mantle length of 54 mm to 179 eggs in the female with a mantle length of 100.5 mm. The relationship between mantle length (ML) an body weight (BW) was BW=0.008 ML$^{2.2797}$ (n=389, r$^2$=0.83, p<0.01) in males and BW=0.029 ML$^{2.2797}$ (n=407, r$^2$=0.74, p<0.01) in females. Analysis of co-variation showed that the difference in the slopes of the two regression lines was significant (p<0.01). Analysis of mantle length-frequency for each month revealed 1 to 3 normal distribution modes. The growth parameters obtained by fitting the modal progression to the seasonalized von Bertalanffy growth function (VBGF) were ML$\infty$= 112.38 mm, K=1.9, C=0.90, and WP=0.1. The results indicate that the seasonal growth oscillation of the stock is very strong and winter is the season when growth is the slowest.

• Development and Reproduction
• /
• v.10 no.4
• /
• pp.215-225
• /
• 2006

Precocious puberty is defined as the appearance of secondary sex characteristics before age 8 years in girls (or menarche before age 9 years) and before 9 years in boys. The age of onset of puberty is progressing to younger age. The pubertal activation of gonadotrophin releasing hormone(GnRH) release requires coordinated changes in excitatory or inhibitory amino acids, growth factors, and a group of transcriptional regulators. A number of factors affecting precocious puberty were explored, including the role of genetic factors, nutrition(body fat) and exposure to endocrine disrupting chemicals. In addition to the psychosocial disturbances associated with precocious puberty, the premature pubertal growth spurt and the accelerated bone maturation result in reduced adult height. Precocious puberty may be gonadotrophin-dependent premature activation of the GnRH pulse generator or gonadotrophin-independent. In rapidly progressing central precocious puberty, GnRH agonists appear to increase final height. However more data on the effect and long-term safety of GnRHa are needed.

• The korean journal of orthodontics
• /
• v.49 no.6
• /
• pp.360-371
• /
• 2019

Objective: We sought to determine the predictors of midpalatal suture expansion by miniscrew-assisted rapid palatal expansion (MARPE) in young adults. Methods: The following variables were selected as possible predictors: chronological age, palate length and depth, midpalatal suture maturation (MPSM) stage, midpalatal suture density (MPSD) ratio, the sella-nasion (SN)-mandibular plane (MP) angle as an indicator of the vertical skeletal pattern, and the point A-nasion-point B (ANB) angle for anteroposterior skeletal classification. For 31 patients (mean age, 22.52 years) who underwent MARPE treatment, palate length and depth, MPSM stage and MPSD ratio from the initial cone-beam computed tomography images, and the SN-MP angle and ANB angle from lateral cephalograms were assessed. The midpalatal suture opening ratio was calculated from the midpalatal suture opening width measured in periapical radiographs and the MARPE screw expansion. Statistical analyses of correlations were performed for the entire patient group of 31 subjects and subgroups categorized by sex, vertical skeletal pattern, and anteroposterior skeletal classification. Results: In the entire patient group, the midpalatal suture opening ratio showed statistically significant negative correlations with age, palate length, and MPSM stage (r = -0.506, -0.494, and -0.746, respectively, all p < 0.01). In subgroup analyses, a strong negative correlation was observed with the palate depth in the skeletal Class II subgroup (r = -0.900, p < 0.05). Conclusions: The findings of this study indicated that age, palate length, and MPSM stage can be predictors of midpalatal suture expansion by MARPE in young adults.

• Fisheries and Aquatic Sciences
• /
• v.24 no.12
• /
• pp.437-445
• /
• 2021

Roughscale sole (Clidoderma asperrimum) is only wild caught because basic reproductive research on this species is lacking and gamete production in an artificial setting has not been successful. Exogenous hormone treatment has been used to induce gonadal maturation and final spermiation in wild-caught individuals. In this study, the effects of an exogenous hormone on spermiation in roughscale sole was investigated by implanting different concentrations of a salmon gonadotrophin-releasing hormone analog (sGnRH; 0, 25, 50, and 100 ㎍/kg body weight) into male fishes. The control group did not produce sperm after 21 days post-implantation, and the duration of spermiation was shorter compared to the other groups. The spermiation period and milt amount differed among the hormone-treated groups according to the hormone concentration used. Milt volumes in the groups treated with 25 and 100 ㎍/kg sGnRH increased compared to the control group, whereas exogenous hormone treatment had no effect on the movable sperm ratio. The spermatocrit was high at the beginning of spermiation in all groups and then tended to decrease gradually over time except in the experimental group treated with 100 ㎍/kg sGnRH. Plasma levels of testosterone, 11-ketotestosterone, 17α, 20β-dihydroxy-4-pregnen-3-one were not significantly affected by the sGnRH treatments. Our results demonstrate that it is possible to prolong the spermiation period and increase milt volume by treating male roughscale soles with an exogenous hormone. In addition, the artificial hormone treatment did not affect sperm motility.

• Korean Journal of Ichthyology
• /
• v.34 no.1
• /
• pp.16-24
• /
• 2022

The eggs development and early life history of Sarcocheilichthys variegatus wakiyae was investigated. The adult fishes were collected in Yeongsangang River, Damyang-gun, Jeollanam-do, Korea, and their spawning inducement was carried by sex maturation hormone (Ovaprim) injections. Spawning amount was mean 31±3.5 Mature eggs were cicular in shape and mean 2.40±0.05 mm in diameter. Hatching period of the embryo was 230 to 240 hours after fertilization under water temperature of 22℃. The newly hatched larvae were 10.7±0.19 mm in total length (TL). 3 days after hatching, postlarvae was measured 12.0±0.13 mm in TL and the tip of the caudal fin was bent at 45°. 11 days after hatching, it was measured 14.6±0.13 mm in TL, and transferred to juvenile as the number of fins (iii7 dorsal fin, iii6 anal fin, i7 ventral fins) reached a constant number of each part.

• Anatomy and Cell Biology
• /
• v.56 no.1
• /
• pp.86-93
• /
• 2023

Age at death estimation has always been a crucial yet challenging part of identification process in forensic field. The use of human skeletons have long been explored using the principle of macro and micro-architecture change in correlation with increasing age. The clavicle is recommended as the best candidate for accurate age estimation because of its accessibility, time to maturation and minimal effect from weight. Our study applies pre-trained convolutional neural network in order to achieve the most accurate and cost effective age estimation model using clavicular bone. The total of 988 clavicles of Thai population with known age and sex were radiographed using Kodak 9000 Extra-oral Imaging System. The radiographs then went through preprocessing protocol which include region of interest selection and quality assessment. Additional samples were generated using generative adversarial network. The total clavicular images used in this study were 3,999 which were then separated into training and test set, and the test set were subsequently categorized into 7 age groups. GoogLeNet was modified at two layers and fine tuned the parameters. The highest validation accuracy was 89.02% but the test set achieved only 30% accuracy. Our results show that the use of medial clavicular radiographs has a potential in the field of age at death estimation, thus, further study is recommended.