An immunohistochemical study of retinol-binding protein (RBP) in livers of free-living polar bears (Ursus maritimus) from east Greenland.

From 1999 to 2002 samples from 114 free-ranging polar bears (Ursus maritimus) were collected in the municipality of Scoresby Sound, East Greenland, to detect levels of organochlorines and potential histopathologic changes. Livers of 16 female polar bears from this group were evaluated histologically and analyzed for hepatic retinol-binding protein by immunohistochemistry. Retinol-binding protein is the main transport protein for retinol, an important vitamin A metabolite in the polar bear. Only mild pathologic changes were noted on histologic evaluation of the livers. Small lymphocytic or lymphohistiocytic infiltrates were present in all the livers. Small lipid granulomas, mild periportal fibrosis, and bile duct proliferation were found in several cases. Immunohistochemistry for retinol-binding protein of hepatic tissue from free-ranging polar bears showed no distinct difference in staining intensity by a number of criteria: age, season (fasting and nonfasting), or lactation status. The staining was diffuse to finely stippled in the cytoplasm and showed very little variation among the animals. Because of the lack of macroscopic changes and the absence of severe histologic liver lesions, these polar bears were assumed to be healthy. The diffuse cytoplasmic retinol-binding protein staining in hepatocytes of free-ranging polar bears varies markedly from the prominent granular, less intense staining of captive polar bears investigated previously.     

Polyvinylsulfate: interaction with complexes of morphogenetic factors and their natural inhibitors

The inactivation of the mesodermalizing inducing factor by its natural inhibitor is completely abolished by low concentrations of polyvinylsulfate.     

上海嘉定区杨白潜蛾的生物学特性及防治

2002～2004年对杨白潜蛾(LeucopterasusinellaHerrich-Schаffer)的生物学特性进行了研究,结果发现杨白潜蛾在上海1年发生5代,幼虫共5龄,1年有2个发生高峰期:6月中旬和9月中下旬;老熟幼虫作白色“H”形茧化蛹;以蛹在树干周围场所越冬;成虫产卵单列成行。药剂试验表明杀虫安、甲氨基阿维菌素、快绿扬、斑潜净对喷雾杨白潜蛾具有很高的防效,对杨树也有很好的保叶效果。     

Chromatin Configurations in the Ferret Germinal Vesicle that Reflect Developmental Competence for In Vitro Maturation

In several mammalian species, the configuration of germinal vesicle (GV) chromatin correlates with the developmental competence of oocytes. Yet, no study has been published on the configuration of GV chromatin in ferret, nor is it known whether a specific configuration predicts meiotic competence in this species, in spite of the potential importance of ferret cloning to the study of human disease and to species conservation efforts. Here, we report on an analysis of the chromatin configuration in ferret GV oocytes and on how they correlate with meiotic development. Three distinct configurations were identified based on the degree of chromatin condensation: (1) fibrillar chromatin (FC), featuring strands of intertwined chromatin occupying most of the visible GV region; (2) intermediate condensed chromatin (ICC), characterized by dense, irregular chromatin masses throughout the GV; and (3) condensed chromatin (CC), which is highly compact and centered around the nucleolus. We also found that chromatin configuration was related to the extent of association with cumulus cells in cumulus–oocyte complexes; CC-configured oocytes were most often surrounded by a compact cumulus layer and also a compact corona but FC-configured oocytes were associated with neither. In addition, increasing chromatin condensation corresponded to an increase in oocyte diameter. Finally, following in vitro culture, significantly more CC-configured oocytes underwent maturation to meiotic metaphase II than did FC- or ICC-configured oocytes. We conclude that, in ferret, chromatin condensation is related to the sequential achievement of meiotic competencies during oocyte growth and differentiation, and thus can be used as a predictor of competence.     

Larval fish movement in the River Lohajang,Tangail, Bangladesh

Larval fish drift and distribution patterns were studied in the River Lohajang, a tributary of the River Jamuna, Bangladesh, during the monsoon seasons (June - October) of 1992, 1993 and 1994. Larval fish drift peaks with the water levels of the River Jamuna. In all three years, the Indian carp, Catla catla, Labeo rohita L. and Cirrhinus mrigala, were associated with the first pulses, but were absent from drift samples after September. Hilsa species and other non-identified fish species were found throughout the monsoon season. The highest larval fish densities were found in the upper strata of the river, near the shore. The drift densities of these fish became evenly distributed through time. Water turbidity probably influenced the vertical and horizontal distribution, and the absence of diel patterns. The most important species in the larval drift were Hilsa spp., followed by Labeo rohita L., Glossogobius giuris L. and Rasbora daniconius. Among the major carp, Labeo rohita was the dominant species, contributing 80-90%. The impact of flood control programmes on the reproduction of riverine and larval fish drift is discussed.     

Studies on the artificial propagation of Monopterus albus (Zuiew)

Artificial propagation of Monopterus albus (Zuiew) was conducted during their spawning season in the present study. Different doses of luteinizing-hormone-releasing-hormone analogue (LHRH-A) were tested for inducing the ovulation of brood females. No significant difference was found in the degree-hours and fertilization rates between three different doses (0.1, 0.2 and 0.3 μg LHRH-A g^-1 fish). A fertilization solution of 0.3% NaCl produced significantly higher fertilization rates than the other three solutions (0.5% NaCl, 0.65% NaCl and water). Fertilization times ranging from 5 to 2 0 min gave no significant difference in the fertilization rates. The embryonic and larval development of M. albus was observed and illustrated. The hatching time of eggs of M. albus was about 140 h in the 28-3 0^oC water temperature range. Using Tubifex spp. for the first food for the larval nursery gave higher growth rate than two other foods, zooplankton and artificial food.     

Odor cues during slow-wave sleep prompt declarative memory consolidation

Sleep facilitates memory consolidation. A widely held model assumes that this is because newly encoded memories undergo covert reactivation during sleep. We cued new memories in humans during sleep by presenting an odor that had been presented as context during prior learning, and so showed that reactivation indeed causes memory consolidation during sleep. Re-exposure to the odor during slow-wave sleep (SWS) improved the retention of hippocampus-dependent declarative memories but not of hippocampus-independent procedural memories. Odor re-exposure was ineffective during rapid eye movement sleep or wakefulness or when the odor had been omitted during prior learning. Concurring with these findings, functional magnetic resonance imaging revealed significant hippocampal activation in response to odor re-exposure during SWS.     

Seasat mission overview

During some 3 months of orbital operations, Seasat collected a unique set of global synoptic data on ocean winds, waves, temperature, and topography. All indications from a preliminary analysis of these data are that most of the mission's proof-of-concept objective-the demonstration of nearly all-weather microwave surveillance of the world's oceans-will be met.