Decay of female sexual behavior under parthenogenesis

A laboratory strain of Drosophila mercatorum has existed for 20 years without males and therefore without natural selection operating to maintain the genetic basis of female mating behavior. The females of this strain have recently experienced a genetic impairment of mating capacity. This observation exemplifies the mode of evolution of vestigial characters and supports Muller's theory that random mutation will tend to destroy the genetic basis of a character from which selection has been removed.     

Antigen recognition by rainbow trout (Oncorhynchus mykiss) of whole cell proteins expressed by Lactococcus garvieae when obtained directly from fish and under iron limited culture conditions

Infection by Lactococcus garvieae has become a widely recognised problem associated with intensively cultured fish. Long-term control of fish infections may be possible by vaccination providing a suitable and efficacious epitope is expressed during production of cells used for vaccine preparation. The identification of novel vaccine candidates must, therefore, consider how the host species recognises and responds to bacterial cell components. L. garvieae was cultured in iron deficient, limited and haem iron enriched media and the whole cell proteins expressed under these conditions were compared with those expressed in bacteria extracted with Percoll gradients directly from spleen tissue of infected rainbow trout (Oncorhynchus mykiss). SDS-PAGE of the cell proteins showed the existence of several different electropherotypes according to the iron status of the culture media. Only minor differences in cell protein profile were detected in bacteria obtained directly from fish spleens, but when the electropherograms were analysed by Western blots using L. garvieae hyperimmune fish sera, several proteins could be identified that were expressed only when L. garvieae was growing in vivo. Siderophore could be detected in culture supernatant of iron deficient, limited and haem iron enriched media but not in media with higher nutrient concentrations. The siderophore could not be identified as a type of catechol or hydroxymate. Rainbow trout recognise proteins in the range of approximately 50-80 kDa for bacterial cells obtained without subculture from infected fish and culture conditions can influence protein profiles for this pathogen.     

Effects of testicular biopsy in clinically normal bulls

OBJECTIVE: To determine whether testicular needle biopsy is detrimental to testicular function in clinically normal bulls. DESIGN: Prospective study. ANIMALS: 6 mixed-breed mature bulls. PROCEDURE: A randomly selected testicle from each bull was biopsied with a 14-gauge needle biopsy instrument. Bulls were then evaluated over a 90-day period for changes in scrotal temperature and thermal patterns, ultrasonographic appearance, and quality of spermatozoa. At the end of the 90-day study, bulls were castrated, and testicles were examined grossly and histologically. RESULTS: Changes were detected in scrotal temperatures and thermal patterns and in the breeding soundness examination results during the first 2 weeks of the study. However, there were no long-term changes in semen quality over the course of the experiment. Hyperechoic areas were detected on ultrasonographic examination and corresponded to the areas of penetration by the biopsy instrument. Microscopic lesions that were indicative of testicular dysfunction were not found. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that testicular biopsy is a safe procedure in bulls. Testicular biopsy could possibly be used to further examine bulls that have less than satisfactory results for breeding soundness examinations.     

Theileriosis in a Missouri beef herd caused by Theileria buffeli: case report, herd investigation, ultrastructure, phylogenetic analysis, and experimental transmission

A 6-year-old Simmental cow infected with Theileria buffeli had a clinical disease characterized by theilerial parasitemia, macrocytic normochromic anemia with acanthocytosis and spherocytosis, lymphoid hyperplasia (lymphocytosis, edematous lymphadenomegaly), dysproteinemia, evidence of liver disease, and a low serum antibody titer against T. buffeli. The cow was in a herd in which all cattle originated in Missouri; 22/75 (29%) of cattle had a theilerial parasitemia and 26/75 (35%) had titers to T. buffeli of > or =1:160. Classification of the Missouri bovine organism as T. buffeli was based on DNA sequencing and comparison to sequences for T. buffeli and Theileria sp. type A obtained from GenBank. Intraerythrocytic veils and piroplasms were seen during transmission electron microscopy. The organism was successfully transmitted to two splenectomized calves, which developed mild anemias while parasitemic. Blood from the second calf was used as the source of T. buffeli antigen for an indirect immunofluorescence antibody test. Theilerial isolates from a Missouri white-tailed deer were also sequenced and resembled Theileria sp. types F and G and were not consistent with the bovine organism.     

Endometrial and serum gentamicin concentrations in pony mares given repeated intrauterine infusions

Endometrial tissue and blood serum gentamicin (GT) concentrations were determined in 6 ovariectomized pony mares given intrauterine infusions (50 ml of a 5% commercial aqueous solution of GT) each day for 5 consecutive days. The mares were subjected to the following 3 treatments: (1) GT infusion only (trial A, control); (2) progesterone plus GT (trial B, P + G); and (3) estradiol plus GT (trial C, E + G). Endometrial tissue concentrations of GT (micrograms/g) at 24 and 120 hours were significantly higher (P less than 0.05) in trials B (65.54 +/- 15.57 and 100.33 +/- 19.27) and C (73.33 +/- 22.53 and 74.09 +/- 8.60) than in trial A (4.23 +/- 0.70). Endometrial concentration for trial A at 120 hours was also significantly higher than trial A at 24 hours. There was no significant difference (P greater than 0.05) in endometrial concentrations among trials A, B, and C at 120 hours. Serum GT concentrations were significantly lower than endometrial tissue concentrations. The highest serum concentrations of GT found in every trial occurred at 6 hours after each intrauterine infusion of GT. The highest overall serum concentration of GT (micrograms/ml) determined occurred in trial B (8.30 +/- 1.28) at 78 hours. There was no significant difference in serum concentrations of GT between days of treatment, except for trial A at 78 and 102 hours, respectively. Serum concentrations of GT were significantly higher (P less than 0.05) than trial A at 30, 54, 78, and 102 hours in trial B, and at 78 and 102 hours in trial C. There was no significant difference in serum concentrations of GT between trials B and C.     

Presence of anti-Neoparamoeba sp. antibodies in Tasmanian cultured Atlantic salmon, Salmo salar L

Previous studies have indicated that when Atlantic salmon, Salmo salar L., are exposed to Neoparamoeba sp. the fish produce anti-Neoparamoeba sp. antibodies. It appears unlikely that these antibodies elicit any specific protection against amoebic gill disease (AGD) as fish with demonstrable activities have been affected by AGD. Experiments were conducted on Atlantic salmon cultured throughout Tasmania to assess the natural production of antibodies towards Neoparamoeba sp. Fish were sampled from areas where AGD was prevalent and from areas where there had been no reported cases. An enzyme-linked immunosorbent assay (ELISA) was used to measure anti-Neoparamoeba sp. antibody activities in serum. All fish from sea water had antibody activities greater than the negative control fish, including fish from areas with no reported cases of AGD. Time trial samples indicated that time after transfer to sea water did not appear to be a significant (P > 0.05) factor in antibody activity, however location was (P < 0.05). There was no agreement (corrected kappa value, 0.16) between the ELISA result and the isolation of Neoparamoeba sp. from the gills of the same fish. The results suggest that Atlantic salmon in seawater culture in Tasmania produce anti-Neoparamoeba sp. antibodies regardless of infection history, suggesting the presence of Neoparamoeba sp. in the environment.