The study of non-typhoid Salmonella in broiler integrations has been limited by the resolution of typing techniques. Although serotyping of Salmonella isolates is used as a traditional approach, it ...is not of enough resolution to clearly understand the dynamics of this pathogen within poultry companies. The aim of this research was to investigate the epidemiology and population dynamics of Salmonella serotypes in 2 poultry integrations using a whole genome sequencing approach. Two hundred and forty-three Salmonella isolates recovered from the broiler production chain of 2 integrated poultry companies were whole genome sequenced and analyzed with dedicated databases and bioinformatic software. The analyses of sequences revealed that S. Infantis was the most frequent serotype (82.3%). Most isolates showed a potential for resistance against medically important antibiotics and disinfectants. Furthermore, 97.5% of isolates harbored the pESI-like mega plasmid, that plays an important role in the global dissemination of AMR. SNP tree analysis showed that there were clones that are niche-specific while other ones were distributed throughout the broiler production chains. In this study, we demonstrated the potential of whole genome sequencing analysis for a comprehensive understanding of Salmonella distribution in integrated poultry companies. Data obtained with these techniques allow determination of the presence of genetic factors that play an important role in the environmental fitness and pathogenicity of Salmonella.
During early lactation, dairy cow are prone to developing severe mastitis in responses to intramammary Escherichia coli infections. These severe inflammatory responses have been correlated with ...reduced neutrophil function during the periparturient period. However, the causative mechanism of neutrophil dysfunction has not been elucidated. Studies in murine sepsis models have shown that during sepsis neutrophils are functionally paralysed due to the presence of high concentrations of complement factor 5a (C5a). In this review, we hypothesize that C5a as a critical early mediator in the development of severe E. coli mastitis. Furthermore, preliminary data suggest that crosstalk between C5a and TLR4 signalling in neutrophils may provide a positive feedback mechanism that may be involved in the pathogenesis of a severe mastitis response. Finally, we focus on the therapeutic potential of disrupting the C5a signalling pathway as an important strategy for treatment of severe E. coli mastitis in dairy cattle
The objective of the current study was to investigate (i) the outcome of experimentally induced Escherichia coli mastitis in primiparous cows during early lactation in relation with production of ...eicosanoids and inflammatory indicators, and (ii) the validity of thermography to evaluate temperature changes on udder skin surface after experimentally induced E. coli mastitis. Nine primiparous Holstein Friesian cows were inoculated 24 ± 6 days (d) after parturition in both left quarters with E. coli P4 serotype O32:H37. Blood and milk samples were collected before and after challenge with E. coli. The infrared images were taken from the caudal view of the udder following challenge with E. coli. No relationship was detected between severity of mastitis and changes of thromboxane B2 (TXB2), leukotriene B4 (LTB4) and lipoxin A4 (LXA4). However, prostaglandin E2 (PGE2) was related to systemic disease severity during E. coli mastitis. Moreover, reduced somatic cell count (SCC), fewer circulating basophils, increased concentration of tumor necrosis factor-α (TNF-α) and higher milk sodium and lower milk potassium concentrations were related to systemic disease severity. The thermal camera was capable of detecting 2-3°C temperature changes on udder skin surface of cows inoculated with E. coli. Peak of udder skin temperature occurred after peak of rectal temperature and appearance of local signs of induced E. coli mastitis. Although infrared thermography was a successful method for detecting the changes in udder skin surface temperature following intramammary challenge with E. coli, it did not show to be a promising tool for early detection of mastitis.
Peroxisomes are organelles that are essential for normal development in men and mice. In order to explore whether zebrafish could be used as a model system to study the role of peroxisomes, we ...examined their distribution pattern in developing and adult zebrafish and we tested different approaches to eliminate them during the first days after fertilization. In 4-day-old embryos, catalase-containing peroxisomes were obvious in the liver, the pronephric duct and the wall of the yolk sac, but transcripts for peroxisomal matrix and membrane proteins were also detected in the head region from 24 h post-fertilization. In adult zebrafish, catalase-containing peroxisomes remained prominent in the hepatocytes, the renal proximal tubules and the intestinal epithelium. Several peroxins, essential proteins for the biogenesis of peroxisomes, were targeted using knockdown approaches. Two morpholinos, blocking, respectively, splice sites in
pex3
and
pex13
, only induced a short in frame deletion or insertion in the transcripts and did not result in the elimination of peroxisomes after injection into one-cell embryos. A morpholino blocking translation of
pex13
was able to reduce the number of peroxisomes to variable extents. Finally, overexpression of a potential dominant negative fragment of Pex3p did not result in deletion of peroxisomes from developing zebrafish. We conclude that in zebrafish (1) peroxisomes, as visualized by DAB cytochemistry for catalase activity, are most conspicuous in the liver and renal tubular epithelium; this pattern is reminiscent of peroxisome occurrence in mammalian organs, (2) our approaches to eliminate these organelles during development by targeting peroxins were not successful.
There is cumulating evidence that microRNAs (miRNAs) are important regulators of pluripotency and differentiation and, hence, of early lineage segregation in embryo development. To unravel the ...function of specific miRNAs, it is important not only to analyze miRNA expression in the entire blastocyst but also to determine the site and level of expression in the inner cell mass (ICM) versus trophectoderm (TE). A new strategy has been developed for miRNA expression analysis in ICM and TE using two complementary techniques. By whole mount in situ hybridization (WISH), it was visualized that bta-miR-155 is mainly expressed in the ICM. However, WISH does not provide quantitative data on expression differences between the two cell types. By reverse transcription quantitative polymerase chain reaction (RT–qPCR) on ICM and TE isolates taken from single blastocysts with laser capture microdissection (LCM), it was quantified that bta-miR-155 was 50-fold higher expressed in ICM than in TE. The possibility to quantify both miRNAs and messenger RNAs (mRNAs) in LCM samples offers the opportunity to analyze the expression of both miRNAs and potential targets in one sample. This article shows that a combination of WISH with LCM and subsequent RT–qPCR is a robust strategy to qualitatively and quantitatively analyze differential miRNA expression in discrete cell types of a single blastocyst.
In this study, we isolated and analyzed a small heat shock protein (HSP) of Ostertagia ostertagi (Oo-HSP18). Oo-hsp18 is encoded by a single-copy gene and the full-length cDNA represents an 18-kDa ...protein. The expression of Oo-hsp18 is highly stage specific and restricted to the adult stage. The protein is synthesized in a tissue-specific manner and localized in the body muscle layer. The levels of Oo-hsp18 mRNAs are sharply induced by heat shock but not by other stressors such as levamisole and H2O2. A vaccination trial with recombinant Oo-HSP18 failed to protect calves against a challenge infection.
While considerable research in education has established objective and subjective status differences between tracks and focused on the outcomes of ability grouping on students' educational and ...broader outcomes, there is virtually no research that explains students' variability in track valuation. This study relies on theoretical insights from social psychology, ethnic studies and school effects research to develop hypotheses about the influence of individual and school level features on students' track valuation. Data from The School, Identity and Society survey, involving 4,540 adolescents from 64 Belgian schools is utilised, using multilevel modelling. The findings show the relevance of social identity theory and social norms in students judging all tracks; and track chauvinism, patriotism and cross-track friendships in explaining variability in students' prejudice towards other tracks. However, these relationships vary according to the track position of the student. The conclusions discuss the implications of this study for future research and social policy.
Prior research has demonstrated the adverse effects of ability grouping (here tracking) on a broad range of outcomes for secondary school students, including their self‐esteem. A recent line of study ...focuses on the importance of track identities in understanding how ability grouping impacts students. This study builds on these findings by investigating the role of public track regard and chauvinistic track identification on the relationship between track membership and general self‐esteem. Multilevel modeling of school survey data collected from 4,540 third‐year high school students from 64 schools in Belgium shows that students' public track regard correlates positively with their general self‐esteem. In addition, while students' chauvinistic track identification does not protect against societal judgment, it does associate with general self‐esteem. The type of chauvinism, either social or cognitive, that correlates with self‐esteem is track‐dependent. The conclusions discuss the implications of these findings for research and social policy.
This study focuses on the interplay of perceived ethnic discrimination by teachers, parents’ ethnic socialization practices, and ethnic minority students’ sense of academic futility. Since ...discrimination creates barriers beyond control of the individual, the first research goal is to examine the association of perceived ethnic discrimination by teachers with ethnic minority students’ sense of academic futility. The second research goal is to focus on the role of perceived parental ethnic socialization (e.g., cultural socialization and preparation for bias) to get a better understanding of the interaction between family level factors and the potentially negative consequences of ethnic teacher discrimination. A multilevel analysis on 1181 ethnic minority students (50.6 % girls; mean age = 15.5), originating from migration, in 53 secondary schools in Flanders (Belgium) shows that the frequent perception of ethnic discrimination by teachers is associated with stronger feelings of academic futility, and if these students also received high levels of parents’ ethnic socialization, they perceive even stronger feelings of futility. The group of ethnic minority students, who perceive frequent ethnic teacher discrimination, is a group at risk, and parents’ ethnic socialization does not seem able to change this.
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