Micro-environmental conditions modulate protein secretion and infectivity of the Trichinella spiralis L1 larva

After digestion of infected meat the free L1 of Trichinella spp. penetrate the intestinal mucosa where they moult to the mature adult stage. We have used proteomics to identify changes in protein secretion during in vitro culture of free T. spiralis muscle larvae under different environmental conditions, and to correlate these changes with their infectivity in mice. Muscle larvae were cultured in different media (RPMI-1640, C-199 and HBSS) under conditions of anaerobiosis, microaerobiosis and in 5% CO₂ at 37 °C. Following incubation the larval excretory/secretory proteins were analysed by two-dimensional gel electrophoresis and the larvae were used to orally infect naïve CD1 mice. For all culture media tested, infectivity of the L1 was preserved following incubation in anaerobic conditions. In contrast, the infectivity of worms cultured in nutrient-rich media was almost completely abolished in both microaerobiosis and in the presence of 5% CO₂. Some infectivity was retained in poor or reduced culture media. Comparative analysis of larval infectivity and protein secretion showed that loss of infectivity correlated with the appearance of non-tyvelosylated proteins that in turn may be related to the onset of moulting.     

Contribution of family labour to the profitability and competitiveness of small-scale dairy production systems in central Mexico

The objective of this work was to determine the effect of family labour on the profitability and competitiveness of small-scale dairy farms in the highlands of Central Mexico. Economic data from 37 farms were analysed from a stratified statistical sampling with a Neyman assignment. Three strata were defined taking herd size as criterion. Stratum 1: herds from 3 to 9 cows plus replacements, Stratum 2: herds from 10 to 19 cows and Stratum 3: herds from 20 to 30 cows. The policy analysis matrix was used as the method to determine profitability and competitiveness. The coefficient of private profitability (CPP) when the economic cost of family labour is included in the cost structure was 8.0 %, 31.0 % and 46.0 %. When the economic cost of family labour is not included, CPP increase to 47.0 %, 57.0 % and 66.0 % for each strata, respectively. The private cost ratio (PCR) when family labour is included was 0.79, 0.51 and 0.42 for strata 1, 2 and 3, respectively. When family labour is not included, the PCR was 0.07, 0.25 and 0.26. Net profit per litre of milk including family labour was US$0.03 l^-1 for Stratum 1, US$0.09 for Stratum 2 and US$0.12 l^-1 for Stratum 3; but increased to $0.12, 0.14 and 0.15, respectively, when the economic cost of family labour is not included. It is concluded that family labour is a crucial factor in the profitability and competitiveness of small-scale dairy production.     

Normal bacterial flora from vaginas of Criollo Limonero cows

In order to describe the normal bacterial flora in vaginas of Criollo Limonero cows, 51 healthy multiparous cows, at least 90-day postpartum, were selected. Duplicated swabs (N = 102) were taken from the vaginal fornix of cows to perform aerobic and anaerobic cultures as well as conventional biochemical tests. Out of 102 swabs, bacterial growth was obtained in 55 (53.9%) while the remaining 47 (46.1%) did not exhibited any bacterial growth. Of the 55 bacterial growths, 23 (41.8%) were aerobic whereas 32 (58.1%) were anaerobic. Likewise, 29 (52.72%) of bacterial growths were pure and 26 (47.27%) were mixed. Under both aerobic and anaerobic conditions, Gram positive bacteria were predominant (81.82% and 73.08%, respectively) over Gram negative bacteria (18.18% and 26.92%, respectively). Isolated bacteria were Arcanobacterium pyogenes (22.92%), Staphylococcus aureus (15.63%), Staphylococcus coagulase negative (17.71%), Erysipelothrix rhusiopathiae (6.25%), Bacteroides spp. (13.54%), and Peptostreptococcus spp. (7.29%). In conclusion, normal vaginal bacterial flora of Criollo Limonero cows was predominantly Gram positive and included A. pyogenes, S. aureus, coagulase negative Staphylococcus, E. rhusiopathiae, Bacteroides spp., and Peptostreptococcus spp. In Criollo Limonero cattle, adaptive aspects such as development of humoral and physical mechanisms for defense, and bacterial adaptation to host deserve research attention.     

Genetic typing of classical swine fever virus

Three regions of the classical swine fever virus (CSFV) genome that have been widely sequenced were compared with respect to their ability to discriminate between isolates and to segregate viruses into genetic groups. Sequence data-sets were assembled for 55 CSFVs comprising 150 nucleotides of the 5' non-translated region, 190 nucleotides of the E2 envelope glycoprotein gene and 409 nucleotides of the NS5B polymerase gene. Phylogenetic analysis of each data-set revealed similar groups and subgroups. For closely related viruses, the more variable or larger data-sets gave better discrimination, and the most reliable classification was obtained with sequence data from the NS5B region. No evidence was found for intertypic recombination between CSFVs. A larger data-set was also analysed comprising 190 nucleotides of E2 sequence from 100 CSFVs from different parts of the world, in order to assess the extent and global distribution of CSFV diversity. Additional groups of CSFV are evident from Asia and the nomenclature of Lowings et al. (1996) [Lowings, P., Ibata, G., Needham, J., Paton, D., 1996. J. Gen. Virol. 77, 1311-1321] needs to be updated to accommodate these. A tentative assignment, adapting rather than overturning the previous nomenclature divides CSF viruses into three groups with three or four subgroups: 1.1, 1.2, 1.3; 2.1, 2.2, 2.3; 3.1, 3.2, 3.3, 3.4. The expanding data-base of CSFV sequences should improve the prospects of disease tracing in the future, and provide a basis for a standardised approach to ensure that results from different laboratories are comparable.     

Mucus characterisation in the Octopus vulgaris skin throughout its life cycle

The development of the epidermis of octopus, Octopus vulgaris, throughout its life cycle was studied by conventional staining and histochemical techniques using lectins. The mantle, the arm and the two parts of the suckers: the infundibulum and the acetabulum were analysed independently. With the exception of the suckers, the general morphology of the epidermis does not vary from the first days post-hatching to adulthood. In general terms, histochemical techniques do not indicate changes in the composition of glycoconjugates of the epidermis main cells, epithelial and secretory cells. The epithelial cells of the mantle and arm show positivity for mannose (ConA+) in their apical portions, indicating the presence of n-glycoproteins that, among other things, provide lubrication to the surface of the body. In the suckers, the apical surface of the infundibulum contains sulphated glycosaminoglycans of the N-acetylglucosamine type that provide adhesive properties. In addition to observing three types of mucocytes, m1 and m2 are characteristic of the mantle and arm, and m3 is found in the suckers. The paralarva epidermis is characterised by the presence of Kölliker's organs whose exact function is unknown. In this study, the absence of staining with alcian blue/periodic acid–Schiff(AB/PAS) prevents the possibility of attributing a secretory function. Nevertheless, the linkage of three lectins (WGA, LEL and GSL-I) in the fascicle of the organ suggests the presence of proteoglycans rich in N-acetylglucosamine that would mainly have a structural role.     

Follicular wave dynamics and Growth factors gene expression in Braford heifers

The objectives of the present study were (experiment 1) to characterized development and dynamics of the dominant follicles (DF) and the corpus luteum (CL) to determine patterns of two (W2) and three (W3) follicular waves in beef heifers, and (experiment 2) to determine gene expression of growth factors gene expression in follicular cells of W2 and W3 heifer. Twenty-eight Braford heifers were used. Dominant follicular and CL were monitored daily by ultrasonography to identify the development W2 and W3 in heifers. Pre-ovulatory DF were aspirated on day 19 in W2 and on day 22 in W3 heifers. In W2 and W3, follicular cells (FC) of gene expression of growth differentiation factor 9, bone morphogenetic protein 15 (BMP15), fibroblast growth factor basic, transforming growth factor beta receptor 1, bone morphogenetic protein receptor type IB and fibroblast growth factor receptor 2 were evaluated. The regression of the DF of the first follicular wave and the emergency of the DF of the second follicular wave began later in the heifers W2 than in W3 (p = .02 and p < .01). The regression of the CL began earlier in the W2 than in W3 group (p < .01). Gene expression of growth factors and receptors was similar between groups. However, higher relative levels of BMP15 was observed in W2 group (p = .07). Results propose that wave patterns were regulated by the development time of the DF in the first wave and the life of the CL. Furthermore, higher levels of BMP15 could produce shorter life of CL. The present work suggest that ultrasonography associated with molecular assays could be used as an easy and effective tool to characterize follicular wave patterns.     

Studies on the transmission of Theileria annulata to cattle by the tick Hyalomma lusitanicum

The role of the ixodid tick Hyalomma lusitanicum Koch 1844 as a vector of Mediterranean or tropical theileriosis (caused by the protozoan parasite Theileria annulata Dschunkowsky et Luhs 1904) in southern Spain was studied. Hyalomma lusitanicum was the most common tick, and the only species of the genus Hyalomma L., found on T. annulata-infected cattle from the theileriosis enzootic area studied (province of Cádiz, southern Spain). Likewise, we found that all sera of the cattle previously considered as suspected of theileriosis by clinical signs, tested for T. annulata antibodies, were positive and all blood samples of these suspected cattle examined had infected erythrocytes. Partially fed H. lusitanicum adults were collected in the field on T. annulata-infected cattle in this enzootic area and fed on an uninfected calf in an experimental farm free of theileriosis and ticks. At approximately 3 weeks post-tick feeding on the calf, this became positive for T. annulata antibodies and T. annulata merozoites were found in erythrocytes from blood smears. These results show the ability of H. lusitanicum to transmit the protozoan parasite T. annulata to susceptible cattle and indicate that H. lusitanicum is probably an important vector of T. annulata in the enzootic area surveyed.     

Chicken dendritic cells and type II pneumocytes express a common intracellular epitope

1. CVI-ChNL 74·3, a dendritic cell-specific monoclonal antibody (mAb) also identifies chicken lung granular pneumocytes (type II pneumocytes), which produce surfactant.

2. The 74·3 mAb does not cross-react with any other avian or mammalian granular pneumocyte, and provides a convenient tool for monitoring the status of type II pneumocytes in the chicken lung.