Regulation of the length of the fertile period in the domestic fowl by numbers of oviducal spermatozoa, as reflected by those trapped in laid eggs

The numbers of spermatozoa trapped in the vitelline membrane of laid eggs were counted after staining with the fluorochrome 2,4-diamidino-2-phenylindole. In a group of 24 hens inseminated with different numbers of spermatozoa to produce different lengths of fertile periods, the numbers of spermatozoa in successive eggs from each hen decreased logarithmically with respect to days following insemination. A relationship could be described between the numbers of spermatozoa per unit area of membrane of an egg and the probability of that egg being fertile. After insemination the number of spermatozoa on successively-laid eggs appears to become reduced until a critical value is reached, after which the hen will lay infertile eggs. By estimating the day on which the critical value was achieved, the actual length of the fertile period could be predicted. It is suggested that the numbers of spermatozoa trapped in the vitelline membrane of laid eggs represent those which surround the ovum at the time of fertilization.     

Alteration of the anterior acrosome of motile bovine spermatozoa by fructose and hydrogen ion concentration

Storing cauda epididymal spermatozoa in seminal plasma or in defined media at 1 x 10(9) spermatozoa/ml for 24 h at 4 degrees C caused swelling of the apical ridge on motile spermatozoa (SAR) provided concentrations of fructose in the range normally found in seminal plasma or comparable levels of glucose were present. Evaluation of these conditions indicated that, with glycolysable sugars in the media, pH dropped from 6.6-6.7 to 5.7-6.0. Most of the pH decrease occurred during the first 2 h of slow cooling from 37 to 4 degrees C. pH decrease was undoubtedly due to sperm organic acid production which overwhelmed the relatively weak buffering capacity of the defined media and/or seminal plasma. Inducing pH decreases with HCl in fructose-free conditions, and using NaOH to prevent a pH decrease when fructose was included in media, demonstrated that exposing spermatozoa to pH values of 5.7-6.0 and not a specific response to fructose was the major cause of SAR.     

Effects of prostaglandins E-2 and F-2 alpha on the metabolism of [U-14C]glucose by mouse morulae-early blastocysts in vitro

During 5-h culture in the presence of radioactive glucose, PGE-2 (10 micrograms/ml) significantly inhibited incorporation of glucose into the acid-soluble glycogen pool. PGE-2 at 1 and 10 micrograms/ml and PGF-2 alpha at 1 microgram but not 10 micrograms/ml stimulated incorporation of glucose into non-glycogen macromolecules during culture. However, the utilization of acid-soluble glycogen and other biochemical pools was not affected by the presence of PGs in the medium during 24-h chase culture of pulse-labelled embryos. Carbon dioxide production was significantly suppressed in the presence of PGs but accumulation of lactate was not affected. The results indicate that PGE-2 and PGF-2 alpha, in physiological concentrations, directly influence the metabolism of glucose by preimplantation embryos.     

Oral ontogeny of the Ayu, Plecoglossus altivelis and comparisons with the jaws of other salmoniform fishes

The Japanese Ayu, Plecoglossus altivelis Temminck & Schlegel is the sole representative of the salmoniform family Plecoglossidae. The Ayu is remarkable for its dentition which in adults comprises groups of diagonally arranged comb-like teeth in the outer tissue of the jaws. In juveniles (below 63 mm SL) the teeth are attached normally to the jaws. The transition of tooth form is correlated with a switch from zooplanktivory to algal or aufwuchs grazing. The present study follows the development of the teeth, jaws, oral cavity ethmoid and suspensorial elements in specimens ranging in size from 41–70 mm SL. The possible mode of function of the adult dentition is discussed. Comparisons are made with the jaws of other salmoniform fishes and a suite of supposed apomorphic characters are identified which are also shared with certain genera of the family Osmeridae, thus supporting the ideas of others that the Osmeridae is a paraphyletic assemblage.     

Genetic and biological analyses of a herpes simplex virus intertypic recombinant reduced specifically for neurovirulence.

RS6 is a herpes simplex virus intertypic recombinant derived from type 1 strain 17 syn+ and type 2 strain HG52. With a 50% lethal dose of about 10(5) PFU after intracerebral inoculation of mice, RS6 was approximately 100,000 times less neurovirulent than either of its wild-type parental viruses were. When compared with strains 17 syn+ and HG52, RS6 replicated intermediately in primary mouse embryo fibroblasts in vitro at 38.5 degrees C (mouse temperature) and to wild-type peak titers in mouse feet in vivo. In contrast, following intracranial inoculation of mice, RS6 replicated significantly less well than did either of its parental viruses in brains. The genetic defect(s) responsible for the reduced neurovirulence of RS6 was stable after in vitro and in vivo serial passage, was not manifested as temperature-sensitive plaquing in vitro, and did not affect thymidine kinase expression. These data indicate that RS6 has a genetic defect(s) specifically affecting its ability to replicate in the mouse brain. Using marker rescue technologies, we increased the neurovirulence of RS6 and localized one genetic determinant(s) involved with the reduced neurovirulence of this agent to 0.72 to 0.87 map units (and, tentatively, to 0.79 to 0.83 map units) of the herpes simplex virus genome. When coupled with the work suggesting that thymidine kinase expression is essential for efficient replication in nerve tissues and earlier reports from this laboratory and others, the results presented in this study indicate that more than one herpes simplex virus gene is involved with neurovirulence.     

Potential long-acting contraceptive agents: esters of testosterone with alkoxy- and halogeno-substituted carboxylic acids

The chemical synthesis and physical data of several new esters of testosterone (17 beta-hydroxyandrost-4-en-3-one), which contain either a halogeno or an alkoxy substituent in the acid chain, are reported.     

Herbicide tolerant regenerates of potato

Summary Culture-derived plants and cell cultures of potato (Solanum tuberosum L.) respond to the application of the herbicides SYS 67 ME (MCPA) and OMNIDEL (Na-2,2-dichloropropionate) in a comparable fashion. By gradually increasing the herbicide concentration, cell lines were developed which tolerated 50 mg/l of ME or 300 mg/l of OMNIDEL. Any further increase in concentration resulted in the death of all cell cultures. From cell cultures that had been able to grow on media supplemented with 30 mg/l of ME, regenerate plants were obtained that were also tolerant to this concentration. This new trait was retained even after repeated vegetative propagation of the plants.