B. Acosta

The in vitro effect of probiotic Vagococcus fluvialis on the innate immune parameters of Sparus aurata and Dicentrarchus labrax.

In this study we evaluated the effect of the probiotic Vagococcus fluvialis on the cellular immune unspecific system of two different fish species of great interest in aquaculture such as gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax). Leucocytes from head kidney of the two fish species were extracted and concentration adjusted to 10(7) cells ml(-1). Phagocytic and respiratory burst activity and the peroxidase content of leucocytes were observed 30 min after incubation with the probiotic Vagococcus fluvialis alive or inactivated with heat shock or UV-light at different concentrations of 10(7), 10(8), 10(9) cfu ml(-1) (final concentration 10(6), 10(7), 10(8) cfu ml(-1)). V. fluvialis produced dose-dependent increments in respiratory burst in sea bream leucocytes. The respiratory burst activity of sea bream head kidney leucocytes incubated with 10(6) cfu ml(-1) of live and inactivated bacteria was not stimulated. The highest values of peroxidase content were observed in sea bass cells with stimulation indexes higher than 1 in HK leucocytes incubated with 10(8) cfu ml(-1) of live and inactivated bacteria. Statistical analysis revealed that differences being only significant in sea bass leucocytes where 10(8) cfu ml(-1) bacteria denote statistically significant differences (P < 0.05) respect to other concentrations. Highest values of phagocytic activity were obtained in sea bass macrophages incubated with UV-light inactivated bacteria (27.33% ± 1.45), where significantly differences with sea bass HK leucocytes were detected. Our results suggest that the in vitro assays are a useful tool to optimize the effective dose of probiotic bacteria. Although in vivo studies are necessary to confirm the immunomodulatory effect of this strain.

Presence of C. albidus , C. laurentii and C. uniguttulatus in Crop and Droppings of Pigeon Lofts ( Columba livia )

Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this disease.

ISOLATION OF MYCOBACTERIUM KANSASII FROM A TUBERCULIN-POSITIVE GOAT

a comparison between means technique (Carrasco 1986). The effects of treatment on seasonality are shown in Figs 1 and 2. and the results of this study appear to indicate that administration of PGF2a at the time of insemination breaks the seasonality of swine reproduction. Seasonal infertility is associated with impaired secretion of lutenising hormone and thus an increased embryonic mortality, resulting in lower fertility and decreased litter size (reviewed by Love and others 1993). Ovulation is known to be associated with intrafollicular synthesis of PGF2a. Transcervical infusion of PGF2a has been shown to produce an intrafollicular increase of PGF2a concentration, and also to advance ovulation by approximately 12 hours (Weiler and Claus 1991). The results of the present study support this observation and indicate the beneficial effects of ovulation-inducing substances such as PGF2a in the improvement of the success rate of swine artificial insemination, especially during the low fertility season.

Immunization of sea bream (Sparus aurata) juveniles against Photobacterium damselae subsp. piscicida by short bath: Effect on some pro-inflammatory molecules and the Mx gene expression.

Cytokines are a family of proteins derived from macrophages, lymphocytes, granulocytes, mast cells and epithelial cells and can be divided into interferons (IFNs), Interleukins (ILs) and Tumor Necrosis factors (TNFs) among others. The presence of cytokines in a wide number of fish species has been proved and several molecules types have been already cloned and sequenced. In this work some proinflamatory molecules and Mx gene were detected in the liver of vaccinated sea bream juveniles with an average body weight of 5 g. The method of immunization was by short bath and three different bacterins against the marine pathogen Photobacterium damselae subsp. piscicida were designed and used to immunize fish. Five genes encoding for five different molecules were analyzed by real time PCR: IL-1β, IL Ir-2, Cox-2, Mx and TNFα. Gene expression was quantified along four days after fish immunization and results were compared among groups. Results show that the heat-inactivated vaccine stimulates the up-regulation of IL-1β, IL Ir-2, Cox-2 and TNFα genes whereas the UV-light inactivated vaccine was the unique vaccine which stimulates the expression of Mx gene. The present is a novel study that shows by the first time the effect of the inactivation process of vaccines on the expression levels of genes involved in the defense against Photobacterium damselae subsp piscicida.

Interaction of Corynebacterium Pseudotuberculosis With Ovine Cells in Vitro

Caseous lymphadenitis is an infectious and contagious disease caused by Corynebacterium pseudotuberculosis, with a worldwide distribution and high prevalence in small ruminant populations. This disease causes significant economic loss in small ruminants through reduced meat, wool, and milk production. C. pseudotuberculosis can also affect horses, domestic and wild large ruminants, swine, and man. It is considered an occupational zoonosis for humans. As part of in vitro investigations of the pathogenesis of C. pseudotuberculosis, this study analyzed its capacity to adhere to and invade the FLK-BLV-044 cell line, derived from ovine embryonic kidney cells. C. pseudotuberculosis showed a measurable capacity to adhere to and invade this cell line with no significant differences between the four strains assessed. The incubation of the cell line at 4ºC, pre-incubation with sugars, complete and heat inactivated antiserum, and heat-killed and ultraviolet-killed bacteria produced a significant (P < 0.05) decrease in the invasion efficiency or inability to invade the cell line. Plate counting and fluorescence studies showed intracellular bacteria for up to 6 days. Non-phagocytic cells may therefore act as a suitable environment for C. pseudotuberculosis survival and play a role in the spread of infection and/or maintenance of a carrier state.