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The Actinopterygian and specifically the Teleostean peroxisome proliferator-activated receptors (PPARs) present an impressive variability and complexity in their structures, both at the gene and protein levels. These structural differences may also reflect functional divergence from their mammalian homologs, or even between fish species. This review, taking advantage of the data generated from the whole-genome sequencing of several fish species, highlights the differences in the primary structure of the receptors, while discussing results from the literature pertaining to the functions of fish PPARs and their activation by natural and synthetic compounds. [ABSTRACT FROM AUTHOR]

Campylobacter species are one of the leading causes of foodborne disease. Poultry is a major reservoir and source of its transmission to humans. The aim of this study was to estimate the prevalence and antimicrobial resistance of Campylobacter spp. isolated from chicken carcasses, the environment, and processing equipment of a poultry slaughterhouse in Greece, to identify the dominant Campylobacter species and to determine if there are clonal relationships among the isolates. Fifty poultry samples and 25 environmental samples were examined using microbial cultures and PCR. Forty-nine of 50 poultry samples (98%) were found to be positive for Campylobacter spp. The environment of the slaughterhouse was also found to be significantly contaminated with Campylobacter spp. Thirty-seven isolates were found to be susceptible to all antimicrobials tested (56.1%) and 29 isolates showed resistance to at least two of the antimicrobials tested (43.9%). We observed 24 different PFGE-types among the 53 isolates with 14 of them isolated only once, while five PFGE-types were represented by two isolates. The remaining 29 isolates were represented by five PFGE-types each consisting of three to 12 isolates. Regarding the relationship of the PFGE types and corresponding resistance profiles, all strains of each PFGE-type shared the same antimicrobial resistance profile. This study reports evidence for Campylobacter spp. cross-contamination among broiler carcasses in a Greek slaughterhouse.

To maximize growth, farmed fish are fed high-fat diets, which can lead to high tissue lipid concentrations that have an impact on quality. The intake of conjugated linoleic acid (CLA) reduces body fat in mammals and this study was undertaken to determine the effects of dietary CLA on growth, composition, and postprandial metabolic variables in sea bream. Fish were fed 3 diets containing 48 g/100 g protein and 24 g/100 g fat, including fish oil supplemented with 0 (control), 2, or 4% CLA for 12 wk. Feed intake, specific growth rate, total body fat, and circulating somatolactin concentration were lower in fish fed CLA than in controls. Feed efficiency was greater in fish fed 2% CLA than in controls. Liver triglyceride concentrations were higher in fish fed 4% CLA and muscle triglyceride concentrations were lower in fish fed both CLA diets than in controls. Hepatic fatty acyl desaturase and elongase mRNA levels in fish fed CLA were lower than in controls. Metabolic differences between controls and CLA-fed fish were observed at 6 h but not at 24 h after the last meal, including lower postprandial circulating triglyceride concentrations, higher hepatic acyl-CoA-oxidase, and lower L-3-hydroxyacyl-CoA dehydrogenase activities in CLA-fed fish than in controls. Dietary CLA did not affect enzymes involved in lipogenesis including hepatic fatty acid synthase and malic enzyme, but it decreased glucose 6-phosphate dehydrogenase activity at 24 h, but not at 6 h after feeding. The data suggest that CLA intake in sea bream has little effect on hepatic lipogenesis, channels dietary lipid from adipose tissue to the liver, and switches hepatic mitochondrial to peroxisomal [beta]-oxidation.

Abstract: Despite the intensive implementation of control programmes goat, sheep and human brucellosis remains endemic in Greece. As the discrimination between field endemic strains and vaccine strain Rev.1 is not feasible, it is essential to develop new diagnostic tools for brucellosis diagnosis. Moreover, effective disease control requires enhanced epidemiological surveillance in both humans and animals including robust laboratory support. Two new multiplex (duplex) polymerase chain reactions (PCRs) were developed and the results were compared with those obtained by real‐time PCR and bacteriological biotyping. A total of 71 Brucella spp. Greek endemic strains were identified at species and biovar level, using both molecular and conventional techniques. Their discrimination from the vaccine strain Rev.1 was achieved, using polymerase chain reaction‐restriction fragment length polymorphism assay (PCR‐RFLP). All 71 strains were identified as Brucella melitensis by multiplex PCR as well as by real‐time PCR and conventional biotyping. Sixty‐two (87.3%) out of 71 strains were identified as B. melitensis biovar 3, eight (11,3%) strains as biovar 1 and only one (1,4%) as biovar 2. Digestion with PstI restriction enzyme revealed that all strains were field endemic strains, as they gave different patterns from the vaccine strain Rev.1. Brucella melitensis biovar 3 appears to be the predominant type in Greece. The novel multiplex PCR produced results concordant to ones obtained by real‐time PCR and conventional biotyping. This technique could support and facilitate the surveillance of Brucellosis in Greece contributing in the control of the disease. [ABSTRACT FROM AUTHOR]

The correlation between the natural levels of glutathione S-transferase (GST) and the tolerance to the organophosphorus insecticides parathion-methyl and paraoxon-methyl, as well as the interaction of affinity-purified enzyme and the insecticides were investigated in order to collect further information on the role of the glutathione S-transferase system as a mechanism of defence against insecticides in insects. The studies were carried out on the larvae and pupae of the coleopteran Tenebrio molitor L, which exhibit varying natural levels of GSTactivity. Stage-dependent susceptibility of the insect against insecticides was observed during the first 24 h. However, 48 h after treatment, the KD50 value increased significantly due to the recovery of some individuals. Simultaneous injection of insecticide with compoundswhich inhibit GST activity in vitro caused an alteration in susceptibility of insects 24 or 48 h post-treatment, depending on stage and insecticide used. Inhibition studies combined with competitive fluorescence spectroscopy revealed that the insecticides probably bind to the active site of the enzyme, thus inhibiting its activity towards 1-chloro-2,4-dinitrobenzene in a competitive manner. High-performance liquid chromatography and gas chromatography revealed that T molitor GST catalyses the conjugation of the insecticides studied to a reduced form of glutathione (GSH). From the above experimental results, it isconsidered that GST offers a protection against the organophosphorusinsecticides studied by active site binding and subsequent conjugation with GSH. [ABSTRACT FROM AUTHOR]

BackgroundBrucellosis is a bacterial zoonosis causing severe illness in humans and animals and leading to economic losses in the livestock production in Türkiye and other endemic countries.AimWe aimed at investigating genomic differences of Brucella isolates from animals and humans in Türkiye.MethodsWe used whole genome sequencing (WGS) to assess the genetic diversity of Brucella isolates from 41 provinces in Türkiye and compared with isolates from other countries. We applied allele-based typing and core genome single nucleotide polymorphism (cgSNP) determination.ResultsOf the 106 Turkish Brucella isolates included, 57 were B. abortus and 49 were B. melitensis . One B. melitensis and two B. abortus isolates were identified as vaccine strains. Most (n = 55) B. abortus isolates clustered in three major branches, with no spatial discernible pattern. Of the B. melitensis isolates , 48 were assigned to the Eastern Mediterranean lineage with no discernible patterns between host species, location and sampling date. The Turkish isolates clustered with isolates from neighbouring countries such as Greece and Syria, but some also with isolates from human patients in European countries, like Germany, Norway and Sweden, suggesting that the source may be travel-related.ConclusionSeveral B. melitensis and B. abortus lineages are circulating in Türkiye. To decrease the prevalence and prevent brucellosis in animals and humans, stricter control measures are needed, particularly in areas where humans and animals have close contact. Furthermore, illegal transportation of animals across borders should be more closely controlled and regulated.

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily that functions as critical regulators of lipid and energy homeostasis. Although intensively studied in mammals, their basic biological functions are still poorly understood. The objective of this work was to characterize PPARbeta subtypes in a fish, the Atlantic salmon (Salmo salar), in order to address PPAR function and the regulation of lipid homeostasis in lower vertebrates. The screening of an Atlantic salmon genomic library revealed the presence of four genes for PPARbeta subtypes. Based on comparisons of exons and exon-flanking regions, these genes were assigned into two families, ssPPARbeta1 and ssPPARbeta2, each family containing two isotypes: ssPPARbeta1A and beta1B and ssPPARbeta2A and beta2B. Two full-length cDNAs for ssPPARbeta1A and ssPPPARbeta2A were isolated. Transcripts for ssPPARbeta1A and ssPPARbeta2A have distinct tissue expression profiles, with ssPPARbeta1A predominating in liver and ssPPARbeta2A predominating in gill. Expression levels of mRNA of either isotypes were up to tenfold lower in kidney, heart, spleen, muscle, and brain. In cellular transfection assays, ssPPARbeta1A is activated by monounsaturated fatty acids, 2-bromopalmitate, and mammalian PPARbeta-specific ligand GW501516. In contrast, PPARbeta2A was not activated by any of the compounds tested. Furthermore, ssPPARbeta2A repressed both the basal reporter gene activity and the GW501516-induced activity of ssPPARbeta1A. The results indicate unexpected levels of variety and complexity in PPAR subtype and mechanism of action in lower vertebrates.