Effects of Natural EstradioI-17β and Synthetic 17α- Ethynylestradiol on Direct Feminization of European Sea Bass Dicentrarchus labrax

To produce a monosex female population of European sea bass Dicentrarchus labrax, fry were fed dry diets containing dosages of 12.5, 25, and 50 mg/kg food of either the natural estrogen estradiol-170β(E₂) or the synthetic estrogen 17α-ethynylestradiol (EE₂) for 60 d starting at 88 d post-hatch (dph). A complete feminization (100%) was achieved in all E₂-treated groups at the age of 11 mo (330 dph). All affected fish had ovaries similar in size and histological structure to those of control females. In the E₂-treated groups, feminized fish were heavier and longer than untreated controls (males and females combined). In control groups females exhibited significantly higher body weight and total length than males. Untreated females from control groups and females from the group treated with E₂ at 12.5 mg/kg food had similar body weight, suggesting that in sea bass growth is related to phenotypic sex. In the Entreated groups, survival rates were similar to those of the control fish. A relatively high percentage of females was obtained in the EE₂-treated groups (from 38.6 to 96.5%). However, the gonadal development in these fish was significantly suppressed and a dose-dependent reduction of gonadal sizes was evident. Treatments with the EE₂ (12-5, 25, and 50 mg/kg food) resulted in many fish having abnormal (2.9-5.4-39.8%, respectively) and sterile (0.6-6.0-21.6%, respectively) gonads. Effects also included significantly lower weight and shorter length when compared with controls. Furthermore, fish fed with EE₂ at the dosage of 50 mg/kg food had high mortality rate. A simple protocol was developed for the complete feminization in sea bass in which the fry (80-100 dph) were fed to satiation two times daily with a diet containing 12.5 me of E₂/ks food for a period of 60 d.     

Riding arenas and different riding track surfaces in relation to the airway contamination in horses. Laboratory studies on riding surfaces]

29 samples of commonly used surfaces were tested for their water characteristics (litre weight, water capacity, water binding, water evaporation) and their contribution to airborne fungal spores (dust formation, dust setting). The results are discussed in comparison to the literature with regard to the environment. The results are: 1. Any surface--no matter of what material--eventually causes air pollution with fungal spores and dust. 2. Correct watering prevents air pollution by any surface. 3. Artificial products have no advantage over natural materials in the parameters tested. 4. The question of proper disposal of old surface material has to be clarified before purchase. The results show that a mixture of sand and wood shavings should be recommended as a surface for indoor arenas, especially in regard to environmental protection and proper disposal.     

The effects of low voltage current on healing of thermal third degree wounds.

Bilateral third degree burns were created on the flanks of eight miniature swine. Each animal had one side treated daily with low intensity direct (LIDC) of 400 microamperes (muA) by contact electrode for 2 hours morning and afternoon until healing occurred. The polarity of the electrode was negative in 4 pigs and positive in 4 pigs. One group of 4 pigs had the eschar surgically removed 24 hours post burn. Weekly biopsies and cultures were taken of treated and control wounds. Results indicated: local treatment of 400 muA LIDC did not hasten or delay healing of thermal third degree burns; escharectomy hastened wound healing by 10 days, and superficial proteus infection occurred in 80% of all wounds.     

Molecular evidence for cosmopolitan distribution of platyhelminth parasites of tunas (Thunnus spp.)

Global distribution of platyhelminth parasites and their host specificities are not well known. Our hypothesis was that platyhelminth parasites of large pelagic fishes are common around the world. We analysed molecular variation in three different taxa of platyhelminth parasites infecting four species of tunas: yellowfin tuna (Thunnus albacares, Scombridae) from Western Australia, southern bluefin tuna (Thunnus maccoyii, Scombridae) from South Australia, Pacific bluefin tuna (Thunnus orientalis, Scombridae) from Pacific Mexico and northern bluefin tuna (T. thynnus, Scombridae) from two localities in the Mediterranean (Spain and Croatia). Comparisons of ITS2 and partial 28S rDNA demonstrated two congeneric species of blood flukes (Digenea: Sanguinicolidae) from multiple hosts and localities: Cardicola forsteri from southern bluefin and northern bluefin tunas, and Cardicola sp. from Pacific bluefin and northern bluefin tunas; and a gill fluke, Hexostoma thynni (Polyopisthocotylea: Hexostomatidae), from yellowfin, southern bluefin and northern bluefin tunas. Partial 28S rDNA indicates that a second type of fluke on the gills, Capsala sp. (Monopisthocotylea: Capsalidae), occurs on both southern bluefin and Pacific bluefin tunas. This appears to be the first report of conspecific platyhelminth parasites of teleosts with a wide‐ranging geographical distribution that has been confirmed through molecular approaches. Given the brevity of the free‐living larval stage of both taxa of flukes on the gills (H. thynni and Capsala sp.), we conclude that the only feasible hypothesis for the cosmopolitan distribution of these flatworms is migrations of host tunas. Host migration also seems likely to be responsible for the widespread occurrence of the two species of blood flukes (Cardicola spp.), although it is also possible that these were translocated recently by the spread of infected intermediate hosts.     

III. Buchbesprechungen

Ohne Zusammenfassung     

Beobachtungen über Erholung von Scheintodlähmungen durch Kontaktgifte bei Cerambyciden

Ohne Zusammenfassung     

Neuraminidase production by Erysipelothrix rhusiopathiae

In order to characterise neuraminidase activity by Erysipelothrix, 85 isolates of Erysipelothrix spp. from a variety of sources including human clinical, marine and terrestrial animals, and the environment were investigated for neuraminidase production. Neuraminidase activity was detected by a peanut lectin haemagglutination method. The effects of media, incubation conditions and pH on the production and activity of neuraminidase were also investigated. Enzyme activity was detected only in the supernatants of the isolates of Erysipelothrix rhusiopathiae which had been incubated in cooked meat broth and Todd Hewitt broth supplemented with horse serum after 16 and 36 h incubation at 37 degrees C. The maximum titres were reached at 40 h in cooked meat broth and 56 h in Todd Hewitt broth supplemented with horse serum. All 58 isolates and the type strain (ATCC 19414) of E. rhusiopathiae produced detectable neuraminidase activity with titres between 10 and 320. The optimal pH for the enzyme activity varied among the isolates with a pH between 6.0 and 7.0 covering the highest enzyme activity of the most. There was no statistically significant difference in the level of neuraminidase activity between isolates from different sources (p > 0.05). Neuraminidase activity was not detected in the non-pathogenic Erysipelothrix spp. such as E. tonsillarum. Neuraminidase was detected only in E. rhusiopathiae suggesting its possible role as a virulence factor. Enzyme production and activity were medium and pH dependent. The peanut lectin haemagglutination assay is a simple, rapid and sensitive method and is particularly useful for the analysis of multiple samples.