Studies on the rabbit proacrosin-acrosin system

A single molecular form (Mr = 68,000 approx) of a homogeneous preparation of rabbit testis proacrosin (S. K. Mukerji and S. Meizel (1979) J. Biol. Chem. 254, 117;21-11728) was initially converted by autoactivation into an acrosin (Mr = 68,000); both gave a single activity and protein bands with similar electrophoretic mobilities (Rm = 0.25) when subjected to polyacrylamide disc gel electrophoresis on 7.5% gel at pH 4.5. Two additional bands (Rm values of 0.395-0.412 and 0.497-0.519, respectively) were noticeable only when proacrosin was activated further after attaining maximum activity. The slowest- and the fastest-moving bands were separated into two acrosin activity peaks by Sephadex G-100 gel-filtration chromatography on a calibrated column. The molecular weights of the two proteins, determined by rechromatography on the same column, was estimated to be 68,000 and 34,000, respectively. Also, sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis of three acrosins gave protein bands which corresponded to molecular weights of approximately 68,000, 52,000, and 34,000, respectively. Electrophoresis data suggest that the loss of acrosin activity generally observed following prolonged activation of proacrosin is caused by self-aggregation of the Mr 34,000 form of acrosin. This property was not shown by Mr 68,000 acrosin. Initial acrosin (Mr = 68,000) was activated by divalent cations such as Ca2+ and Mg2+. The enzyme was inhibited by Zn2+, Fe2+, Hg2+, and sulfhydryl blockers such as 5,5'-dithiobis(2-nitrobenzoic acid), p-hydroxymercuribenzoate, and iodoacetate, apparently due to their reaction with one out of six titratable sulfhydryl groups per mole of acrosin. Probably Zn2+ is involved in acrosomal stabilization. The initial rabbit acrosin (Mr = 68,000) appears to be the major and most stable form, and is generated from proacrosin with little structural alteration. This may be the functionally active form which plays an essential role in mammalian fertilization.     

WHBE 兔、日本大耳白兔和新西兰兔遗传多样性的 RAPD 分析

目的：应用随机引物扩增多态性DNA技术（ random amplified polymorphic DNA , RAPD）对大耳白黑眼兔（ white hair black eyes rabbit , WHBE rabbit ）、日本大耳白兔（ Japanese white rabbit , JW rabbit ）和新西兰兔（New Zealand white rabbit, NZW rabbit）3个实验兔品系进行遗传分析。方法选用90只实验兔的皮肤组织样品提取基因组DNA,用60个随机引物对实验兔基因组DNA进行PCR扩增,根据电泳结果筛选出多态性较高的引物进行RAPD-PCR分析,再利用Popgene 3．2统计软件对3个品系的扩增条带进行遗传分析,获得实验数据。结果分析结果表明：（1）60个随机引物中筛选出25个多态性较高的引物,3个品系实验兔共检测到493个扩增片段,长度在100～1800 bp之间,筛选的25个引物中,其中16个引物既可扩增出3个品系共同的DNA条带,也可扩增出WHBE兔特有的特征条带;（2） WHBE兔位点数为234个,其中多态位点数166个,多态位点比为70．94％,JW兔位点数为228个,其中多态位点数122个,多态位点比为53．51％,NZW兔位点数为231个,其中多态位点数94个,多态位点比为40．69％;（3）三个群体的Shannon多样性指数分别为0．3385,0．2222和0．1905;（4） JW兔和NZW兔的遗传相似系数最高,为0．8443,其次为WHBE兔和JW兔的遗传相似系数,为0．8204,WHBE兔和NZW兔的遗传相似系数最低,为0．7862。结论结果表明WHBE兔与JW兔和NZW兔之间有遗传的相似性,也存在着遗传差异,应用RAPD技术可以很好地检测实验兔不同品系之间以及同一品系不同个体之间的亲缘关系。     

Urolithiasis and cystotomy in the rabbit

Cystotomy is a surgical incision into the urinary bladder, which may be required for removal of calculi, diagnosis of tumors or refractory urinary tract infections, or repair of ectopic ureters and ruptured bladders. This column describes the indications and techniques for cystotomy in the rabbit.     

Ultrastructural observations on the renal papilla of the rabbit

Summary Ultrastructural studies of renal papillae of New Zealand brown rabbits under different states of water balance indicate no morphological variation between control, antidiuretic and diuretic animals; the only exception being a decrease in the amount of glycogen in the collecting duct cells in the antidiuretic state and an increase in the diuretic.The light cells of the collecting ducts have a low electron density and show a paucity of organelles. These comprise mitochondria, Golgi apparatus, multivesicular bodies, sparse endoplasmic reticulum and free ribosomes. The centrally-placed, spherical nucleus demonstrates large numbers of nuclear pores. The lateral surfaces and bases of the cells have considerable infoldings which may have functional significance.The attenuated endothelial cells of the vasa recta are punctuated by fenestrations which are most frequently crossed by membrane. The cells contain micropinocytotic and pinocytotic vesicles.The loops of Henle in the papilla are lined by squamous cells which are extended longitudinally in the form of interdigitating processes. The bases of the cells of most loops are scalloped.The interstitial cells are embedded in an amorphous matrix containing occasional collagen fibres and strands of fibrillar material. The cells are irregular in outline and have moderately developed endoplasmic reticulum and Golgi apparatuses.Tight junctions between the cells of all collecting ducts, loops of Henle and vasa recta are a constant finding. All these tubular elements are surrounded by a prominent basement membrane; that associated with the loops of Henle tends to be multiplied, particularly at scalloped regions. The membrane associated with the vasa recta is single except at regions where it projects across the interstitium to the membranes of the collecting ducts and loops of Henle.The functional implications of these findings are discussed.