Quantitative analysis of pattern of gonial proliferation during sexual maturation in Japanese scallop <Emphasis Type="Italic">Patinopecten yessoensis</Emphasis>

ABSTRACT:   This study was undertaken to describe and quantitatively analyze the pattern of development of gametes in the Japanese scallop Patinopecten yessoensis . Incorporation of 5-bromo-2'-deoxyuridine (BrdU) into gonial cells was used to quantitatively detect mitotically active gonial cells. Oogonia increased in number from November to December and decreased rapidly to March. A small number of oocytes was detected in November. Oocytes steadily increased in number and size up to March. The number of spermatogonia slightly increased from November to December, and increased markedly from January to March. Both ratios of BrdU-immunopositive gonial cells in the ovary and testis to gonial cells moderately increased from September to December. The ratio of BrdU-immunopositive spermatogonia to gonial cells drastically increased from January to February and kept an elevated level in March, whereas the oogonia started to disappear in January. The results suggest that the pattern of proliferation of gonial cells can be divided into two phases: (i) phase I, oogonia and spermatogonia slowly proliferate through the growing stage; and (ii) phase II, oogonia develop into oocytes and spermatogonia begin to proliferate rapidly through the mature and spawning stages. The proliferation of gonial cells is likely under different endocrine controls in phases I and II.     

栉孔扇贝夏季大规模死亡的神经网络预测模型

为了比较3种扇贝血液中的K⁺、Na⁺、Ca²⁺和Cl⁻浓度,血氧(pO₂)和血二氧化碳(pCO₂)气体分压及血液酸碱度（pH）的差异情况,实验利用血气分析仪对栉孔扇贝、虾夷扇贝和海湾扇贝的血液生理指标进行测定。结果显示,扇贝的血液生理指标呈现显著的物种差异,其中栉孔扇贝血液的K⁺浓度[(15.74±1.47) mmol/L]、Na⁺浓度[(388.07±11.38) mmol/L]、Cl⁻浓度[(462.43±6.88) mmol/L]和pO₂ [(140.13±15.35) mmHg]最高。此外,栉孔扇贝和虾夷扇贝的Ca²⁺浓度和pCO₂含量较高,而海湾扇贝的pH最高。对相同月龄不同大小栉孔扇贝血液指标进行比较,发现栉孔扇贝的血液pH值与其壳高呈正相关(r=0.611),而生理指标与壳高呈负相关。随着温度的升高,栉孔扇贝血液的Ca²⁺浓度显著增加,而pO₂显著下降,K⁺、Na⁺和Cl⁻浓度先升高后恢复到初始水平,而pH和pCO₂保持相对稳定。研究结果为贝类血液生理研究提供参考,也为贝类生理状态的评估提供了一种新的思路与方法。     

Preparation of Water-Soluble Chitosan and its Suppressive Effect on the Denaturation of Scallop Adductor Muscle Myofibrillar Protein During Frozen Storage

ABSTRACT

In the present study, investigated were the preparation of water-soluble chitosan (WSC) by hydrolysis of original chitosan with commercial α-amylase and the suppressive effect of WSC on denaturation of bay scallop adductor muscle myofibrillar protein (Mf) during frozen storage at ?18°C for 12 months. The WSC (2.5- to 10-g dry weight) was added to 100 g of the Mf, and the changes in the Ca-ATPase activity, solubility, and sulfhydryl content were examined during frozen storage. The addition of WSC significantly reduced the denaturation of the Mf Ca-ATPase. Moreover, a significant increase in Mf solubility and sulfhydryl content was observed in the WSC-treated bay scallop adductor muscles compared with the control (p < 0.05) during frozen storage at ?18°C.     

The pathogenesis of experimental Haemonchus longistipes infection in camels

The pathogenesis and clinical signs of Haemonchus longistipes infection were studied in four experimentally infected camels two of which were adults and the other two were young. In the former animals, an acute infection developed, characterized by mucoid diarrhoea, anorexia, anaemia, loss of body weight, oedema of the lower parts of the limbs, general malaise and death at 8-10 weeks post-infection. In the two younger camels, a less dramatic disease was encountered with less severe symptoms and no oedema, but also terminating fatally at 19-20 weeks post-infection. Parasitological, haematological and biochemical parameters were determined during the course of the infection and were mostly comparable with those usually encountered in haemonchosis of other animals.     

Ultrasonographic appearance of the craniocervical junction in normal brachycephalic dogs and dogs with caudal occipital (Chiari-like) malformation

Ultrasonographic evaluation of the spine, especially of the spinal cord, has been rarely reported in dogs. The atlanto-occipital junction provides a small acoustic window through which examination of the craniocervical transition can be performed. Normal sonographic findings of this region in 10 normal brachycephalic dogs are presented and compared with sonographic findings from 25 Cavalier King Charles Spaniels with the caudal occipital malformation syndrome. Sonographic findings were compared with magnetic resonance imaging findings to determine the extent of cerebellar herniation and syringohydromyelia. Cerebellar displacement into the foramen magnum was clearly identified sonographically; however, syringohydromyelia was not discernable due to bone overlay.     

Limaria hians (Mollusca: Limacea): a neglected reef‐forming keystone species

1. The case is made for recognition of the marine bivalve Limaria hians as a reef‐forming species, which plays a key architectural role in certain benthic communities around the United Kingdom and Ireland. 2. This species uses byssal threads to construct nests that can coalesce to form reefs that cover hectares of seabed, contain multiple conspecifics and bind sediment. In so doing, L. hians modifies physical, chemical and biological processes at the sediment–water interface. 3. Such nests support a high diversity of associated organisms in coarse‐grade sediments (19 species of algae and 265 species of invertebrates from six discrete nests in Loch Fyne are reported on), although the biological interactions between species both inside and outside this assemblage (e.g. predatory cod) are unknown. 4. Being insubstantial, labyrinthine structures situated on the sediment surface, Limaria nests are sensitive to mechanical impacts, such as those caused by moorings, hydraulic dredging for infaunal bivalves and scallop dredging. 5. At appropriate sites, the status of L. hians can contribute a useful indication of disturbance on coarse‐grade sediments. Copyright © 2000 John Wiley & Sons, Ltd.     

刈割和施肥对热研4 号王草生物量影响初报

采用随机区组设计研究刈割时间、刈割次数和施肥量对热研4号王草生物量的影响,结果表明,热研4号王草在海南夏季6～8月份60 d的生长期内,刈割时间间隔20 d、刈割3次的处理,第2次刈割的鲜草生物量最大,且不受施肥量的影响。但当施肥量为1 563 kg/hm~2时的牧草生物量最大,为41 340.10 kg/hm~2;刈割时间间隔30 d、刈割2次的处理,除施肥量为3 127 kg/hm~2的处理外,第1次刈割均比第2次刈割产量高,且差异显著。在相同施肥量下,就单次刈割生物量和总生物量而言,刈割时间间隔越长、刈割次数越低,鲜草生物量就越大,刈割时间为50 d和60 d之间鲜草生物量差异不显著,而与其他处理差异显著,不同的施肥条件下,在刈割时间间隔40 d时,施肥量为4 690 kg/hm~2比施肥量为1 563 kg/hm~2的产量显著增加。在刈割时间间隔50 d和60 d时,随着施肥量的增加,产量并无差异。     

试论牛王节所反映的民间信仰的特点

“牛王节”是西南地区传统的祭神爱牛节日,在明清时期的西南地区的方志中已有记载,在这些记载中,“牛王节”既是一个汉族的民间节日,也是少数民族的民间节日,另外,西北、华中、华南和华东的某些地区,也过“牛王节”。作为一种民间风俗,牛王节必有其民间信仰的特点,本文拟就牛王节的具体内容浅论其所反映的民间信仰的特点。     

糖蜜对不同比例干稻草和王草混合青贮品质的影响

为探究添加糖蜜对不同比例干稻草和王草混合青贮品质的影响,试验设定四个不同比例干稻草和王草混合,添加干稻草比例分别为0％(T1组)、10％(T2组)、20％(T3组)、30％(T4组),并分别对青贮料做无添加处理和糖蜜添加处理.结果 表明:随着稻草比例的增加,粗蛋白质(P＜ 0.001)、粗脂肪(P＜0.05)呈下降趋势...