Cathelicidins are small, cationic, antimicrobial peptides found in humans and other species, including farm animals (cattle, horses, pigs, sheep, goats, chickens, rabbits and in some species of fish). These proteolytically activated peptides are part of the innate immune system of many vertebrates. These peptides show a broad spectrum of antimicrobial activity against bacteria, enveloped viruses and fungi. Apart from exerting direct antimicrobial effects, cathelicidins can also trigger specific defense responses in the host. Their roles in various pathophysiological conditions have been studied in mice and humans, but there are limited information about their expression sites and activities in livestock. The aim of the present review is to summarize current information about these antimicrobial peptides in farm animals, highlighting peptide expression sites, activities, and future applications for human and veterinary medicine.

-The purpose of this review is to give an overview of our current knowledge on the polymorphisms occurring in genes coding for milk proteins and responsible for quantitative variability in their expression, thus influencing the protein composition of livestock ruminant milk. The overall genomic organisation of the 6 main ruminant milk protein genes: a-lactalbumin, b-lactoglobulin and the four caseins (a s1 , a s2 , b and k), their chromosomal location and their expression pattern are first summarised before presenting general mechanisms controlling gene expression both at the transcriptional and the post-transcriptional levels. Polymorphisms found in cis-regulatory elements, mainly within the 5'-flanking region of the genes encoding b-lactoglobulin and a s1 -and a s2 -caseins, have been found, in cattle, to influence their transcription rate. In addition, polymorphisms found in the transcription unit, within intron as well as exon sequences, have been shown to be responsible for defects in the processing of primary transcripts and/or the export of messenger RNA to the cytoplasm. Mutations responsible for the occurrence of premature stop codons in a s1 -and b-casein mRNAs have been shown to be associated both with a decrease in the level of the relevant transcripts and the existence of multiple forms of messengers due to alternative splicing (exon skipping, usage of cryptic splice sites). Such a situation, well-exemplified by the gene encoding a s1 -casein in the goat, may have dramatic biological consequences (secretion pathway, casein micelle structure, fat content, etc.) by modifying the message and accordingly the primary structure of the protein as well as its expression. Since some of these polymorphisms dramatically affect technological properties of milk, including cheese yields and organoleptic characteristics, methods mainly based on the PCR technique have been designed and applied in selection and breeding programmes to improve milk protein quality.gene expression / milk protein / genetic polymorphism / ruminants Reprod. Nutr. Dev. 42 (2002) 433-459 433

No abstract

Expression patterns of candidate genes with important functions in animal metabolism can help to identify potential molecular markers for cattle production traits. Reverse transcription followed by polymerase chain reaction is a method for rapid and accurate mRNA quantification. However, for exact comparison of mRNA quantity in various samples or tissues, it is important to choose appropriate reference genes. In cattle, little information is available on the expression stability of housekeeping genes (HKGs). The aim of the present study is to develop a set of reference genes that can be used for normalization of concentrations of mRNAs of genes expressed in the bovine liver, kidney, pituitary and thyroid. The study was performed on 6-, 9-, and 12-month-old bulls of dairy and meat cattle breeds. Six HKGs were investigated: ACTB, GAPDH, HPRTI, SDHA, TBP, and YWHAZ. The most stably expressed potential reference HKGs differed among tissues/organs examined: ACTB, TBP, YWHAZ, GAPDH, HPRTI, and SDHA in the liver; GAPDH and YWHAZ in the kidney; GAPDH and SDHA in the pituitary; and TBP and HPRTI in the thyroid. The results showed that the use of a single gene for normalization may lead to relatively large errors, so it is important to use multiple control genes based on a survey of potential reference genes applied to representative samples from specific experimental conditions.

Genetic variations in plasma GH concentrations before and following thyrotropin-releasing hormone (TRH) stimulation and in IGF-I concentrations were studied in 11-mo-old Polish Friesian cattle (104 heifers and 110 bulls). A possible association between stimulated GH release, IGF-I, and the polymorphism in the GH gene causing substitution of leucine-Leu to valine-Val at amino acid position 127 of the protein was also investigated. The GH concentrations were determined in serial plasma samples collected every 15 min from 15 min before to 135 min after intravenous administration of 0.15 microg TRH/kg live weight. The analysis was performed on three variables: baseline (mean of samples at -15 and 0 min), peak (sample at 15 min after injection) and rate (peak minus sample at 60 min, divided by 45 min). The IGF-I concentrations were measured in plasma samples taken before the TRH stimulation. Additionally, first lactation records from the 75 cows earlier tested for GH release and IGF-I were used to study a possible association of milk production traits with GH genotypes. The data were analyzed by multivariate mixed linear models. The heritability of IGF-I reached a higher value (0.35) than variables baseline, peak, and rate (0.02, 0.14, and 0.14, respectively). The GH variables were positively genetically correlated with each other (0.22 to 0.93), whereas they had negative genetic correlations with IGF-I (-0.26). The Val/Val genotypes reached the highest peak value compared with other GH genotypes (P> 0.01), whereas the Leu/Leu genotypes had the highest IGF-I concentrations (P < or = 0.05). Moreover, the Leu/Val heterozygotes were superior to others in milk and protein yields, whereas the Leu/Leu homozygotes reached the highest fat yield (P > or = 0.01). We conclude that GH peak, GH rate, and IGF-I are heritable traits in young dairy cattle and are affected by the Leu/Val polymorphism in the GH gene.

BackgroundMastitis is still considered to be the most economically important infectious disease in dairy cattle breeding. The immune response in mammary gland tissues could help in developing support strategies to combat this disease. The role of neutrophils and macrophages in the innate response of mammary gland is well known. However, the immune response in mammary gland tissues, including levels of antimicrobial peptide transcripts, has not been well recognized. Moreover, most studies are conducted in vitro, on cell cultures, or on artificially infected animals, with analysis being done within a several dozen hours after infection.The aim of the study was to examine the in vivo transcript levels of beta-defensin and cathelicidins genes in cow mammary gland secretory tissue (parenchyma) with the chronic, recurrent and incurable mammary gland inflammation induced by coagulase-positive or coagulase-negative Staphyloccoci vs. bacteria-free tissue.ResultsThe mRNA of DEFB1, BNBD4, BNBD5, BNBD10 and LAP genes, but not of TAP gene, were detected in all investigated samples regardless of the animals’ age and microbiological status of the mammary gland, but at different levels. The expression of most of the beta-defensin genes was shown to be much higher in tissues derived from udders infected with bacteria (CoPS or CoNS) than from bacteria-free udders, regardless of parity. Cathelicidins (CATH4, CATH5 and CATH6) showed expression patterns contrasting those of β-defensins, with the highest expression in tissues derived from bacteria-free udders.ConclusionIncreased expression of genes encoding β-defensins in the infected udder confirms their crucial role in the defense of the cow mammary gland against mastitis. On the other hand, the elevated cathelicidin transcripts in non-infected tissues indicate their role in the maintenance of healthy mammary tissues. The expression levels of investigated genes are likely to depend on the duration of the infection and type of bacteria.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-014-0246-z) contains supplementary material, which is available to authorized users.

BackgroundGenome-wide gene expression profiling allows for identification of genes involved in the defense response of the host against pathogens. As presented here, transcriptomic analysis and bioinformatics tools were applied in order to identify genes expressed in the mammary gland parenchyma of cows naturally infected with coagulase-positive and coagulase-negative Staphylococci.ResultsIn cows infected with coagulase-positive Staphylococci, being in 1st or 2nd lactation, 1700 differentially expressed genes (DEGs) were identified. However, examination of the 3rd or 4th lactations revealed 2200 DEGs. Gene ontology functional classification showed the molecular functions of the DEGs overrepresented the activity of cytokines, chemokines, and their receptors. In cows infected with coagulase-negative Staphylococci, in the 1st or 2nd lactations 418 DEGs, while in the 3rd or 4th lactations, 1200 DEGs were identified that involved in molecular functions such as protein, calcium ion and lipid binding, chemokine activity, and protein homodimerization. Gene network analysis showed DEGs associated with inflammation, cell migration, and immune response to infection, development of cells and tissues, and humoral responses to infections caused by both types of Staphylococci.ConclusionA coagulase-positive Staphylococci infection caused a markedly stronger host response than that of coagulase-negative, resulting in vastly increased DEGs. A significant increase in the expression of the FOS, TNF, and genes encoding the major histocompatibility complex proteins (MHC) was observed. It suggests these genes play a key role in the synchronization of the immune response of the cow’s parenchyma against mastitis-causing bacteria. Moreover, the following genes that belong to several physiological pathways (KEGG pathways) were selected for further studies as candidate genes of mammary gland immune response for use in Marker Assisted Selection (MAS): chemokine signaling pathway (CCL2, CXCL5, HCK, CCR1), cell adhesion molecules (CAMs) pathway (BOLA-DQA2, BOLA-DQA1, F11R, ITGAL, CD86), antigen processing and presentation pathway (CD8A, PDIA3, LGMN, IFI30, HSPA1A), and NOD-like receptor signaling pathway (TNF, IL8, IL18, NFKBIA).Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-017-1088-2) contains supplementary material, which is available to authorized users.

Due to their activity against bacteria, viruses, and fungi, antimicrobial peptides are important factors in the innate resistance system of humans and animals. They are called "new generation antibiotics" for their potential use in preventive and therapeutic medicine. The most numerous group of antimicrobial peptides is a family of cationic peptides which include defensins and cathelicidins. Among them the most common are peptides with a beta-sheet structure containing three intra-molecular disulphide bonds, called defensins, comprising three classes: alpha, beta, and theta. The class of beta-defensins is the largest one. Their transcripts have been found in many tissues of humans and animals. The aim of this paper is to present the current knowledge about antimicrobial peptides from the defensin family in farm animals, their expression, polymorphism, as well as the potential of their use as genetic markers of health and production traits.