Cranial morphological homogeneity in two subspecies of water deer in China and Korea

The water deer (Hydropotes inermis) has conventionally been classified into two subspecies according to geographic distribution and pelage color pattern: H. i. inermis from China and H. i. argyropus from Korea. However, the results of a recent molecular study have called this into question. To further reappraise this classification, we examined morphological variation in craniodental measurements of these 2 subspecies. Results of univariate and multivariate analyses demonstrated that these 2 subspecies are not well-differentiated, suggesting that individuals of the 2 populations share common morphological traits. Despite the distribution of the subspecies at different latitudes, no clear morphocline was detected, suggesting that Bergmann’s rule does not apply in this case. Discriminant analysis indicated that the characteristics of individuals are shared by both populations, suggesting that not all individuals can be assigned to their original population. Results of principal component analysis showed that the two populations shared more than 75% of individuals, congruent with the “75% rule” of subspecies classification. In both the neighbor-joining and unweighted pair group methods with arithmetic mean cluster analyses, specimens of H. i. argyropus and H. i. inermis were highly mixed within the cladograms. These results suggest that the overall morphological variation in the 2 subspecies overlaps considerably and that there is no coherent craniofacial difference between the 2 groups. The present findings combined with prior observations from molecular biogeography point out that the taxonomic division of water deer into 2 subspecies should be revisited.     

Analysis of the equine ovarian structure during the first twelve months of life by three-dimensional internal structure microscopy

A three-dimensional internal structure microscopy (3D-ISM) can clarify the anatomical arrangement of internal structures of equine ovaries. In this study, morphological changes of the equine ovary over the first 12 months of life were investigated by 3D-ISM in 59 fillies and by histological analysis in 2 fillies. The weight and volume of the paired ovaries initially decreased from 0 to 1 months to 2 to 3 months of age and then significantly increased at 8 to 12 months of age. The ovulation fossa was first observed around the 3rd month and became evident after the 6th month. The number of follicles with a diameter of ≥10 mm and the diameter of the largest follicle increased gradually after 6 months of age. On a volume basis, the medulla accounted for nearly 90% of the whole ovary at 0 to 1 months of age, but significantly decreased from 2 to 3 months of age. The volume of the cortex increased progressively after birth and reached approximately 60% of the total volume at 8 to 12 months of age. This significant development of the cortex coincided with the increased number and size of large follicles observed from 6 months of age. These results suggest that the development of the cortex plays a role in the maturation of the follicles and the equine ovary undergoes substantial morphological changes postnatally until puberty.     

转基因大豆GTS40-3-2对子代雄性大鼠主要器官和生殖机能的影响研究

为探讨长期饲喂转基因大豆GTS40-3-2对雄性大鼠器官和生殖机能的影响,本研究将雌、雄大鼠随机分为2组,分别饲喂含转基因和非转基因大豆成分的饲料90 d后,亲代大鼠组内交配获得子代大鼠;子代雄性大鼠断乳后继续饲喂对应饲料30、60和90 d后,摘取子代大鼠睾丸、附睾、脑、心脏、肺脏、肝脏、脾脏、肾脏和肾上腺,检测脏器系数;选取睾丸、附睾、肾、肺制备石蜡切片,观察各器官的组织结构变化;运用实时荧光定量PCR检测睾丸雄性激素合成限制性蛋白葡萄糖转运蛋白8(GLUT8)基因的表达变化;用蛋白酶联免疫反应法进一步验证GLUT8蛋白含量。结果表明,与对照组相比,饲喂30、90 d后9种器官脏器系数均无显著差异(P>0.05);饲喂60 d后,仅肺、附睾脏器系数存在显著差异(P<0.05)。组织切片镜检结果显示,睾丸、附睾、肾、肺未发现明显结构改变;睾丸GLUT8基因转录水平和蛋白水平均未受到显著影响(P>0.05)。综上所述,转基因大豆GTS40-3-2饲料在试验周期内未对子代雄性大鼠各重要器官产生不良影响,对雄性大鼠生殖器官及其生理机能未显示毒性作用。本研究结果进一步拓展了转基因大豆安全评价研究深度,对转基因大豆的推广应用具有重要意义。     

Bio-economic analysis of super-intensive closed shrimp farming and improvement of management plans: a case study in Japan

Fisheries Science - Crustacean aquaculture is a multibillion-dollar industry worldwide that continues to show significant growth. Shrimp farming has been intensified for decades, and...     

Development of phototaxis in the early life stages of Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>

We investigated the development of phototaxis in larval and early juvenile stages of Pacific bluefin tuna Thunnus orientalis to detail behavior development in relation to light. We observed the distribution of Pacific bluefin tuna in an illumination gradient tank from 1 to 26 days after hatching (DAH). Two long rectangular tanks (100 × 10 × 10 cm) were used for experiments; each tank was divided into four sections for observations and one tank was equally illuminated at 1.0 × 10³ lx as the control tank, and the other was at 4.0 × 10², 1.0 × 10³, 1.0 × 10⁴ and 7.0 × 10⁴ lx as the illumination gradient tank. Laboratory-reared larvae and juvenile were released into each tank and acclimatized for 10 min. Thereafter, the number of individuals in each section was counted for 5 times with 10-min intervals. Until 2 DAH (3.6 ± 0.1 mm BL), larvae distributed homogeneously in each section in both tanks. After 3 DAH (3.7 ± 0.1 mm BL) when the eyes of the larvae were pigmented, most fish moved into the 7.0 × 10⁴ lx section in the illumination gradient tank, while fish in the control tank maintained a uniform distribution during the experimental period (Chi-square test, P < 0.05). The results suggest that the post-larvae and juvenile stages show strong positive phototaxis.     

海南岛尖峰岭游耕农业及热带林采伐的生态后果

本文对海南岛尖峰岭半落叶季雨林带的游耕农业及热带山地雨林不同采伐方式与更新方法的生态后果进行了对比实验与调查研究。观测结果说明,游耕农业耕垦期的小气候急剧恶化,水土流失严重,涵水能力降低,地力趋向减退,撩荒期有所好转。采育择伐的更新与生态后果优于径级择伐,更显著优于皆伐。对热带森林的保护与利用对策,提出了建议。     

Changes in crustacean hyperglycemic hormones in Pacific whiteleg shrimp Litopenaeus vannamei subjected to air-exposure and low-salinity stresses

Changes in crustacean hyperglycemic hormone (CHH)-family peptides in response to stress were investigated in Litopenaeus vannamei. Stress treatments consisted of air exposure and low salinity. High-performance liquid chromatography was used to quantify CHH-family peptides in the X-organ?Csinus gland complex (XO?CSG) in the eyestalks. Among the CHH-family peptides analyzed, only the level of sinus gland peptide-G (SGP-G) in the XO?CSG was decreased. SGP-G was also detectable by Western blotting analysis in the hemolymph of animals subjected to stress. These results suggest that SGP-G was secreted from the XO?CSG into the hemolymph during stress. Glucose levels in the hemolymph increased under conditions during which SGP-G was detected in the hemolymph. Hyperglycemia was also observed when SGP-G was injected. SGP-G may function to shift energy use to deal with stress.     

Genetic homogeneity between adult and juvenile populations of <Emphasis Type="Italic">Scombrops gilberti</Emphasis> (Percoid,Scombropidae) in the Pacific Ocean off the Japanese Islands

Scombrops gilberti is a member of the percoid family Scombropidae, which includes a single genus and three to four species worldwide. Little is known about the ecology of this species. Juvenile S. gilberti have been found in the waters off northern Japan (Iwate Prefecture), whereas adults are found in the waters around the southern counterpart (Izu Islands), approximately 700 km from the northern waters. In the present study, we captured immature S. gilberti (106–248 mm standard length, SL) in the northern waters by set net at 8–80 m depth, whereas larger individuals (150–328 mm SL) were captured by trawling at 150–500 m depth. By contrast, only adult S. gilberti (422–590 mm SL) were captured in the southern waters. The genetic composition of the adult population of S. gilberti from the southern waters and of the juvenile population from the northern waters was compared using the nucleotide sequence of the mitochondrial DNA (mtDNA) cytochrome b gene. No significant differences in genetic parameters such as fixation index, neutrality test or mismatch distribution analysis were found between these geographically distinct populations of S. gilberti, showing that these populations are genetically homogeneous.     

Morphology of placentome in Korean water deer Hydropotes inermis argropus

The placenta of the Korean water deer was anatomically examined to accumulate basic information regarding its reproductive system. The convex placentomes with five to nine well-developed pedicles were observed in the whole uterine horns, and therefore, the placenta was classified as oligocotyledonary. The evidence indicating the migration of binucleate cells (BNCs) from trophectoderm to the uterine epithelium led to the histological classification of the placenta as synepitheliochorial. The number of fetuses was markedly higher than that in other ruminant species. However, the number of placentomes was found to be similar to the other Cervidae species. Therefore, these results suggest that the Korean water deer may possess special mechanisms or structures at the fetus attachment site to maintain this unusally high number of fetuses.