Thyroid hormone deficiency in abnormal larvae of the Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

ABSTRACT:   In large-scale rearing of juveniles of the Japanese flounder Paralichthys olivaceus, a certain morphological abnormality occurred spontaneously in 4% of the fish. These fish showed a slight but clearly different appearance from any developmental stage of this species, and did not settle when all the other juveniles in the same tank completed metamorphosis and had settled. From comparisons of external and internal structures between the normal and the abnormal fish, the abnormality was attributed to unbalanced progress of metamorphosis, mainly due to metamorphic stasis. The thyroid of the abnormal fish was apparently activated morphologically. In addition, serum thyroxine (T4) concentrations in the abnormal fish were reduced to less than 1/10 of that of normal fish. After 14 days of T4 treatment (0.1 p.p.m) of the abnormal fish, all the abnormal characteristics disappeared, and the fish recovered to normal, suggesting normal responsiveness to thyroid hormones in peripheral tissues, whereas thiourea treatment (30 p.p.m., 14 days) further delayed metamorphosis. These results suggest that these abnormal fish were suffering from thyroid hormone deficiency, and were unable to secrete a sufficient amount of thyroid hormone to complete metamorphosis.     

日本鳗鲡脾脏抗菌肽抗菌活性检测方法的比较

本试验旨在建立一种在日本鳗鲡脾脏抗菌肽分离纯化过程中简便、灵敏的检测其抗菌活性的方法。试验以日本鳗鲡脾脏分子质量小于10 ku的蛋白质为抗菌肽样品,选择琼脂板孔穴扩散法和微孔液体培养法2种传统方法及微量液体培养法为检测方法,比较这3种方法在抗菌肽对3种鳗鲡常见致病菌株(迟钝爱德华菌、气单胞菌、嗜水气单胞菌)抗菌活性检测中的灵敏度和优缺点。结果表明:与琼脂板孔穴扩散法及微孔液体培养法相比,微量液体培养法简便、易于观察结果,具有最高的灵敏度且样品用量最少,适合在鳗鲡脾脏抗菌肽分离纯化过程中跟踪检测抗菌活性,尤其适合分离纯化后期获得微量单一样品抗菌活性的检测。由此得出,微量液体培养法适用于检测日本鳗鲡脾脏抗菌肽的抗菌活性。     

日本农业女性参与农业及农村发展的现状与分析

日本农业就业人口的半数以上是女性,女性在担负着操持家务、育儿和赡养老人的同时,在农业经营以及农村第二、第三产业方面发挥着重要的作用。而且近年来涌现在农产品加工、销售、流通、观光农园、农家饭庄等与"食"文化相关领域的农村女性呈增长态势,对区域农业的多元化发展和农村的活化方面做出了积极的贡献。中国应该借鉴日本的经验,有意识地创造有利于发挥和释放女性能力的就业环境,不断拓展女性在农业、农村的活动领域,促进当地农业、农村经济的发展。     

Effect of retinoic acid on gene expression profiles of bovine intramuscular preadipocytes during adipogenesis

To investigate genes involved in intramuscular adipogenesis in ruminants, 16 genes with dramatic variable expression were selected. These were selected from the differentiation‐ and proliferation‐phase libraries of our previous serial analysis of gene expression (SAGE) studies of a clonal bovine intramuscular preadipocyte (BIP) cell line. We harvested the BIP cells over 12 days after adipogenic stimulation with all‐trans retinoic acid (ATRA). Quantitative real‐time PCR confirmed the earlier SAGE study results of the expression patterns of 15 of the genes. On day 6, TG accumulation increased significantly in the BIP cells but was completely inhibited in the 3T3‐L1 cells (the monogastric reference). ATRA enhanced expression levels of six genes whereas it suppressed expression of eight genes on day 3 of adipogenesis in the BIP cells. Forty‐eight hours after transfection, the messenger RNA expression level of the adipose differentiation‐related protein (ADFP), encoded by one of the upregulated genes, in the ADFP small interference RNA (siRNA)‐transfected cells was 3.5% of that in negative control‐transfected cells. Also, 6 days after induction the TG level in the ADFP siRNA‐transfected cells was 21.8% lower than that in negative control‐transfected cells. This analysis of gene expression profiles after ATRA treatment will contribute to our understanding of the molecular mechanisms involved in bovine intramuscular adipogenesis.     

Increase in plasma total antioxidant capacity of grazing Japanese Black heifers and cows in forestland in Japan

Blood total antioxidant capacity (TAC) has become a key bio‐marker for animal health. Forest‐grazing cattle are known to forage various native plants that have high TAC. This study evaluated differences of plasma TAC between forest‐grazing (FG) and pasture‐grazing cattle (PG). Experiment 1 monitored the plasma TAC levels of 32 Japanese Black cattle. The level in PG did not change throughout the grazing period. However, that in FG, which increased from summer, was significantly higher than that in PG through fall (P < 0.05). In experiment 2, we used nine Japanese Black heifers and investigated their blood antioxidant parameters and the TAC in plants that the cattle consumed in late June and September. The plasma TAC levels in FG were significantly higher than those in PG in both periods (P < 0.05). Plasma levels of lipid peroxidation in FG tended to be lower than that in PG (P = 0.098). Furthermore, the TAC levels in various species of shrubs and trees consumed by FG were higher than those in pasture grasses. Results of this study show that plasma TAC of grazing Japanese Black cattle in forestland increase from summer through fall.     

Increased ectopic fat cells in the longitudinal muscularis layer of the oviduct isthmus in obese Japanese Black cows

In obese humans, mesenchymal stem cells differentiate to become ectopic fat cells in muscles. These ectopic fat cells inhibit the contraction of vascular smooth muscles. Stem cells have been recently identified in the human oviduct, a structure important in reproduction. We therefore investigated the number of Oil Red O (ORO)‐positive cells in the oviducts of control Japanese Black cows (n = 6; body condition score [BCS], 3.0 on a 5‐point scale) compared to those with diet‐induced obesity (n = 5; BCS, 4.0). We stained the ampulla and isthmus collected on the second day after ovulation with ORO and then counted the positive cells in each layer in 10 cross‐sections of the ampulla or isthmus. The obese group (23.4 ± 3.4 in the 10 sections) had larger numbers of ORO‐positive cells in the longitudinal muscularis of the isthmus (P < 0.05) than did the control group (15.0 ± 2.4). ORO‐positive cells were also observed in all other layers of the isthmus and ampulla; however, the number of cells in these layers did not differ significantly between obese cows and controls. Whether this observed increase in ORO‐positive cells in the oviducts of obese cows affects their reproduction warrants further study.     

东、黄海鱼是鱼集群分布模式的研究

根据７个冬季变水层拖网瞄准捕捞越冬鱼是鱼平均小时产量统计和探鱼仪鱼群映象纪录资料，研究了鱼是鱼集群分布模式和集群密度。鱼是鱼集群分为表层型、中层型和近底层型３种分布模式。１４种典型集群映象有捕捞生产价值。３种模式的鱼是鱼集群密度是：中层型高于近底层型，近底层型高于表层型。使用５２０目×６００毫米变水层拖网瞄准捕捞中层型集群鱼是鱼平均小时产量５．０～１４．０吨、近底层型３．６～４．５吨和表层型２．３～３．０吨