MEDICAL RESEARCH     

Harvey EN 《Science (New York, N.Y.)》1923,57(1478):501-503

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HATCHING OF THE EGGS OF THE "FAIRY SHRIMP"     

Castle WA 《Science (New York, N.Y.)》1938,87(2267):531-534

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Kongresse des Jahres 1938     

F. Stellwaag  B. Götz 《Journal of pest science》1938,14(11):125-129

Ohne Zusammenfassung  相似文献   

Mitteilungen aus der Deutschen Gesellschaft f. angew. Entomologie E.V. Vorstandswahl     

St. 《Journal of pest science》1938,14(12):148-148

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Studien über die Forstorganifation und die Ausübung der Forstgerichtsbarkeit beim Salzmaieramt Craunstein     

Dr. phil. Edgar Kraufen 《European Journal of Forest Research》1938,60(24):770-781

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Some comparisons of dusts for potato leafhopper control on long island     

J. B. Skaptason 《American Journal of Potato Research》1938,15(10):271-277

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Mosaic versus leafroll     

B. A. Brown 《American Journal of Potato Research》1926,3(4):121-122

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Der heutige Stand der Reblausfrage in Ungarn     

J. Jablonowski 《Journal of pest science》1925,1(2):18-19

Ohne Zusammenfassung  相似文献   

Effect of Collection Rhythms and Season on Rabbit Semen Production     

A Nizza  C Di Meo  S Taranto 《Reproduction in domestic animals》2003,38(6):436-439

The effects of collection regimen and time of year on rabbit semen production were determined in this study. A total of 14 crossbreed Hyla bucks were used in winter and summer. In each season, rabbits were assigned to two groups. In group 1, (n = 7) rabbits were subjected to an extensive collection regimen (two ejaculates per male, once daily/week) and in group 2, (n = 7) a semi‐intensive semen collection regimen was performed (two ejaculates per male, twice weekly). The traits recorded for each sample were libido, volume, pH, motility, sperm concentration, percentage of alive spermatozoa and sperm abnormalities. The results obtained in this study indicate that when increasing collection frequency, the rate of useful collections decreased (from 0.81 ± 0.017 to 0.69 ± 0.016; p < 0.01). The rate of useful collection also decreased in the transition from winter to summer (from 0.79 ± 0.018 to 0.70 ± 0.017; p < 0.01). Among the ejaculate characteristics studied, only volume/ejaculate (from 0.64 ± 0.015 to 0.53 ± 0.017; p < 0.01) and spermatozoa/ml (from 406 ± 15 to 359 ± 13 million; p < 0.01) appeared negatively affected by collection. In winter fewer volume/ejaculates were produced (0.55 ± 0.015 vs 0.60 ± 0.016 ml; p < 0.01) and fewer spermatozoa/ml (360 ± 14 vs 394 ± 16 million; p < 0.01) than in summer. The doses produced per ejaculate decreased as collection frequency increased, but the number of doses produced per week was higher in the semi‐intensive than the extensive rhythm (26.5 ± 2.1 vs 20.9 ± 1.5; p < 0.01). The results suggest that a semi‐intensive rhythm may be viewed favourably.  相似文献   

Regulation of Capacitation of Canine Spermatozoa during Co-culture with Heterologous Oviductal Epithelial Cells   总被引：2，自引：0，他引：2  

AM Petrunkina  K Simon  A-R Günzel-Apel  E Töpfer-Petersen 《Reproduction in domestic animals》2003,38(6):455-463

Progress of essential steps of the capacitation is coordinated in the oviductal isthmus, where sperm are stored in close contact with the epithelium. A crucial capacitational event is the phosphorylation of sperm membrane proteins. Regulation of the tyrosine phosphorylation by the oviduct has not been examined in dog sperm yet. The aim of this work was to study the effect of dog sperm binding to porcine oviductal epithelium on capacitation‐induced cellular and molecular changes. Epithelial cells were stripped from the oviducts of post‐puberal sows and cultured for 5–7 days at 39°C and 5% CO₂ on Biomatrix‐covered Chamber slides. Sperm washed through Percoll was co‐incubated with the oviductal epithelium cell cultures in a bicarbonate Tyrode's medium. During co‐incubation, sperm membrane changes, the state of tyrosine phosphorylation and motility were determined after 3, 30, 90, 180, 240 and 360 min. Significant increases in the percentage of capacitated and dead cells were observed in unbound sperm, while bound sperm remained uncapacitated, live and motile. An increasing tyrosine phosphorylation of tail proteins in bound, unbound and control sperm suspensions and a subsequent phosphorylation of head proteins in unbound and control sperm suspensions were observed. A significant difference regarding head phosphorylation (p < 0.05) was found between sperm bound to oviductal epithelium and unbound sperm. Binding occurred mainly in sperm with non‐ phosphorylated heads, while higher proportions of phosphorylated cells were found in unbound populations. The head phosphorylation progressed significantly during incubation in unbound spermatozoa (p < 0.05); however, it was suppressed in population of sperm attached to oviductal epithelium. Significant correlations between motility parameters related to hyperactivation and tail phosphorylation were found in unbound sperm. These observations support the hypothesis that spermatozoa with non‐phosphorylated heads preferentially attach to epithelial cells. It can be concluded that tyrosine phosphorylation of head membrane proteins and capacitation are delayed in canine spermatozoa being in closed contact with oviductal epithelium.  相似文献