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Based on analysis of available genome sequences, five gene lineages of MHC class I molecules (MHC I-U, -Z, -S, -L and -P) and one gene lineage of MHC class II molecules (MHC II-D) have been identified in Osteichthyes. In the latter lineage, three MHC II molecule sublineages have been identified (MHC II-A, -B and -E). As regards MHC class I molecules in Osteichthyes, it is important to take note of the fact that the lineages U and Z in MHC I genes have been identified in almost all fish species examined so far. Phylogenetic studies into MHC II molecule genes of sublineages A and B suggest that they may be descended from the genes of the sublineage named A/B that have been identified in spotted gar (Lepisosteus oculatus). The sublineage E genes of MHC II molecules, which represent the group of non-polymorphic genes with poor expression in the tissues connected with the immune system, are present in primitive fish, i.e. in paddlefish, sturgeons and spotted gar (Lepisosteus oculatus), as well as in cyprinids (Cyprinidae), Atlantic salmon (Salmo salar), and rainbow trout (Oncorhynchus mykiss). Full elucidation of the details relating to the organisation and functioning of the particular components of the major histocompatibility complex in Osteichthyes can advance the understanding of the evolution of the MHC molecule genes and the immune mechanism.

Thrombocytes in vertebrates other than mammals, inter alia in fish, are analogues of platelets in mammals. In Osteichthyes, these cells take part in haemostatic processes, including aggregation and release reactions in cases of blood vessel damage, and in the immune response development as well. This paper discusses the development of thrombocytes in Osteichthyes, taking into account the need to make changes to the concept of grouping progenitor cells as suggested in the literature. The following pages present the morphological and cytochemical properties of thrombocytes as well as their defence functions, and also point out differences between thrombocytes in fish and platelets in mammals. The paper further highlights the level of thrombocytes’ immune activity observed in fish and based on an increased proportion of these cells in response to antigenic stimulation, on morphological shifts towards forms characteristic of dendritic cells after antigenic stimulation and on the presence of surface structures and cytokines released through, inter alia, gene expression of TLR receptors, MHC class II protein-coding genes and pro-inflammatory cytokines. The study also points out the need to recognise thrombocytes in Osteichthyes as specialised immune cells conditioning non-specific immune mechanisms and playing an important role in affecting adaptive immune mechanisms.

Cathelicidins are Important immunological peptides – HDPs (Host Defense Peptides) with high biological activity in mammals, including human and vertebrate animals. These evolutionary ancient molecules in these organisms are natural elements of antimicrobial, antiviral, antifungal and antiparasitic immunity against which germs and parasites have not developed immunity, which makes them alternatives to antibiotics. Catelicidins in human and vertebrates affect the germs and parasites directly and indirectly by activating the immune system.

Relations between the diversity of the fliC gene conditioning flagellum protein in E. coli and the source of the strain origin are presented. The fliC genes have been identified and characterized in commensal E. coli derived from 10 healthy animal species living in Zoo Safari Park (Poland). The fliC gene was found in 150 strains by the PCR method. The amplified fliC products revealed single bands within the range 1.26–2.16 kbp. Forty restriction patterns (classed by restriction analysis with the use of RsaI (PCR-RFLP RsaI; R-types) were determined. The neighbor-joining method was employed to illustrate the distribution of the kinds of R-types. There are 3–8 various R-types of a diversified frequency of occurrence in strains. Application of PCR-RFLP RsaI permitted the identification of alleles of fliC genes characteristic for E. coli and the estimation of their diversity among the animal species. The transmission ways of E. coli fliC+ between organisms of different species were determined and confirmed the role of transmission and horizontal gene transfer in the generation of the allelic diversity of fliC gene in natural E. coli populations. [ABSTRACT FROM AUTHOR]

The Rep-PCR fingerprinting method has been applied to identify genomic diversity of 252 E. coli strains derived in the area of a flowing-water basin. The received results show that applying UPGMA and Nearest Neighbour-Joining clustering methods to statistical analysis of rep-PCR fingerprints has made it possible to discriminate and group the strains, revealing a characteristic structure of E. coli population for particular stands of sample drawing. The proposed procedure of the analysis may be useful for routinely monitoring water quality. [ABSTRACT FROM AUTHOR]

Genetic polymorphism of 83 isolates of E. coli, derived from 4 species of artiodactyla animals living in a relatively close contact on the grounds of a theme park ZOO Safarii Świerkocin (Poland) was determined using the rep-PCR fingerprinting method, which utilizes oligonucleotide primers matching interspersed repetitive DNA sequences in PCR reaction to yield DNA fingerprints of individual bacterial isolates based on repetitive extragenic palindrome (REP) primers. The fingerprint patterns demonstrated the essential polymorphism of distribution of REP sequences in genomes of the examined isolates. The arithmetic averages clustering algorithm (UPGMA) statistical analysis of fingerprints with the use of the Jaccard similarity coefficient differentiated E. coli isolates into three similarity groups containing various numbers of isolates. The groups comprised isolates derived from two, three and four species of the source animals. The isolates derived from each source segregated in the dendrogram in a different way, both within the similarity groups and among them, indicating an individual repertoire of E. coli in the examined species of animals. The similarity relations among E. coli derived from the same source, illustrated in a dendrogram with a number of subclusters of a low mutual similarity (≤20%), indicated an essential interstrain differentiation in terms of the distribution of REP sequences. Our results confirmed the hypothesis of the oligoclonal characters of populations obtained from particular sources. The rep-PCR fingerprinting method with REP primers is simple and highly differentiating and can be recommended for use in explorations of large groups of animals and monitoring the variability of strains. [ABSTRACT FROM AUTHOR]

Physiological parameters in fish provide grounds for conclusions as to the physiological status of the organism. The status is directly related to inner and outer factors, biotic and abiotic influences which act on the organism. Present studies aimed at defining the set of immunological and haematological indices in breams, which form fish populations in Dabie Lake and Szczecin Bay, whose ecosystems differ in water cleanness. Immunological studies in breams involved determining selective defensive functions of neutrophilic granulocytes, expressed by the index of phagocytosis of a standard bacterial strain (Ipg), the percentage of phagocytes which ingested the bacteria (%gp), NBT index, the amount of formazan and the index of myeloperoxidase activity (WA MPO). Haematological studies included determination of absolute leukocyte number and the differential leukocyte pattern. Bacteriological and physicochemical studies were also performed on water samples of reservoir sites from which the fish originated. Results of examination of water samples from Dabie Lake and Szczecin Bay demonstrated a significant level of water pollution in the ecosystems. A definitely higher level of water pollution, particularly in respect to bacterial contamination, was observed in Dabie Lake. Comparison of immunological and haematological results demonstrated significant differences between the two studied bream populations, i.e. those originating from Dabie Lake and the other, originating from Szczecin Bay. Such differences were disclosed both in immunological and in haematological indices. INSET: European Community Post - and Predoctoral Fellowships.... [ABSTRACT FROM AUTHOR]

Our studies were aimed at bacteriological analysis of water in the small municipal lake of Rusałka, in Szczecin. The studies were conducted over four years, in monthly intervals, assuming that the results will enable detailed analysis of bacteriological characteristics of the water in the tested reservoir and will yield sanitary and ecological characteristics of the reservoir. The quantitative estimation included index bacteria for the extent of pollution, index bacteria of sanitary condition, bacteria of selected physiological groups (ammonification bacteria, denitrification bacteria) as well as the presence of thermophile bacteria, sporulating bacteria, bacteria capable of sulphate reduction (Desulfotomaculum nigrificans). Also, the ratio was calculated for foecal-type coli group bacteria to foecal streptococci, treated as an index of origin of foecal--type pollution. The obtained results were subjected to statistical analysis. In the studied lake high values of all the examined parameters were disclosed. The high numerical force of index bacteria for the extent of pollution (TVC 20°C, TVC 37°C) and of index bacteria for sanitary condition (coli group bacteria, foecal type coli group bacteria, foecal streptococci) pointed to contamination of the lake by household sewage. The observed high numbers of bacteria participating in turnover of nitrogen compounds (ammonification and denitrification bacteria) indicated a continuous inflow of nitrogen-rich compounds and development of water self-purification. The values of most studied parameters obtained by us were in general higher than the values noted in the same lake in previous years and higher than the values noted in other municipal lakes in Poland. [ABSTRACT FROM AUTHOR]

The article characterises platelets, pointing out the role and contribution of their numerous receptors determining their specific and broad immune activity. Three types of platelet receptors are described, that is, extracellular and intracellular receptors-TLR (toll-like receptors), NLR (NOD-like receptor), and RLR (RIG-I-like receptor); extracellular receptors-selectins and integrins; and their other extracellular receptors-CLR (C-type lectin receptor), CD (cluster of differentiation), TNF (tumour necrosis factor), among others. Outlining the contribution of these numerous platelet receptors to the intravascular immunity, it has been shown that they are formed by their fusion with pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), and lifestyle-associated molecular patterns (LAMPs). They are initiating and effector components of signal transduction of these cells, and their expression and quantity determine the specific and broad functions of platelets towards influencing vascular endothelial cells, but mainly PRRs (pattern recognition receptors) of blood immune cells. These facts make platelets the fundamental elements that shape not only intravascular homeostasis, as previously indicated, but they become the determinants of immunity in blood vessels. Describing the reactions of the characterised three groups of platelet receptors with PAMP, DAMP and LAMP molecules, the pathways and participation of platelets in the formation and construction of intravascular immune status, in physiological states, but mainly in pathological states, including bacterial and viral infections, are presented, making these cells essential elements in the health and disease of mammals, including humans.

In this paper, the characteristics of 40 so far described virophages-parasites of giant viruses-are given, and the similarities and differences between virophages and satellite viruses, which also, like virophages, require helper viruses for replication, are described. The replication of virophages taking place at a specific site-the viral particle factory of giant viruses-and its consequences are presented, and the defence mechanisms of virophages for giant virus hosts, as a protective action for giant virus hosts-protozoa and algae-are approximated. The defence systems of giant viruses against virophages were also presented, which are similar to the CRISPR/Cas defence system found in bacteria and in Archea. These facts, and related to the very specific biological features of virophages (specific site of replication, specific mechanisms of their defensive effects for giant virus hosts, defence systems in giant viruses against virophages), indicate that virophages, and their host giant viruses, are biological objects, forming a 'novelty' in biology.

Rabbit haemorrhagic disease viruses (RHDV) belong to the family Caliciviridae, genus Lagovirus europaeus , genogroup GI, comprising four genotypes GI.1-GI.4, of which the genotypes GI.1 and GI.2 are pathogenic RHD viruses, while the genotypes GI.3 and GI.4 are non-pathogenic RCV ( Rabbit calicivirus ) viruses. Among the pathogenic genotypes GI.1 and GI.2 of RHD viruses, an antigenic variant of RHDV, named RHDVa-now GI.1a-RHDVa, was distinguished in 1996; and in 2010, a variant of RHDV-named RHDVb, later RHDV2 and now GI.2-RHDV2/b-was described; and recombinants of these viruses were registered. Pathogenic viruses of the genotype GI.1 were the cause of a disease described in 1984 in China in domestic ( Oryctolagus ( O. ) cuniculus domesticus ) and wild ( O. cuniculus ) rabbits, characterised by a very rapid course and a mortality rate of 90-100%, which spread in countries all over the world and which has been defined since 1989 as rabbit haemorrhagic disease. It is now accepted that GI.1-RHDV, including GI.1a-RHDVa, cause the predetermined primary haemorrhagic disease in domestic and wild rabbits, while GI.2-RHDV2/b cause it not only in rabbits, including domestic rabbits' young up to 4 weeks and rabbits immunised with rabbit haemorrhagic disease vaccine, but also in five various species of wild rabbits and seven different species of hares, as well as wild ruminants: mountain muskoxen and European badger . Among these viruses, haemagglutination-positive, doubtful and harmful viruses have been recorded and described and have been shown to form phylogenogroups, immunotypes, haematotypes and pathotypes, which, together with traits that alter and expand their infectious spectrum (rabbit, hare, wild ruminant, badger and various rabbit and hare species), are the determinants of their pathogenicity (infectivity) and immunogenicity and thus shape their virulence. These relationships are the aim of our consideration in this article.

It is assumed that cells corresponding to innate lymphoid cells (ILCs) in humans, in addition to lymphoid tissue inducer cells (LTi), are also found in teleosts. In this systematic group of organisms, however, they are a poorly understood cell population. In contrast to the data on ILCs in humans, which also remain incomplete despite advanced research, in teleosts, these cells require much more attention. ILCs in teleosts have been presented as cells that may be evolutionary precursors of NK cells or ILCs identified in mammals, including humans. It is a highly heterogeneous group of cells in both humans and fish and their properties, as revealed by studies in humans, are most likely to remain strictly dependent on the location of these cells and the physiological state of the individual from which they originate. They form a bridge between innate and adaptive immunity. The premise of this paper is to review the current knowledge of ILCs in teleosts, taking into account data on similar cells in humans. A review of the knowledge concerning these particular cells, elements of innate immunity mechanisms as equivalent to, or perhaps dominant over, adaptive immunity mechanisms in teleosts, as presented, may inspire the need for further research., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The paper presents virophages, which, like their host, giant viruses, are "new" infectious agents whose role in nature, including mammalian health, is important. Virophages, along with their protozoan and algal hosts, are found in fresh inland waters and oceanic and marine waters, including thermal waters and deep-sea vents, as well as in soil, plants, and in humans and animals (ruminants). Representing "superparasitism", almost all of the 39 described virophages (except Zamilon) interact negatively with giant viruses by affecting their replication and morphogenesis and their "adaptive immunity". This causes them to become regulators and, at the same time, defenders of the host of giant viruses protozoa and algae, which are organisms that determine the homeostasis of the aquatic environment. They are classified in the family Lavidaviridae with two genus (Sputnikovirus, Mavirus). However, in 2023, a proposal was presented that they should form the class Maveriviricetes, with four orders and seven families. Their specific structure, including their microsatellite (SSR-Simple Sequence Repeats) and the CVV (cell-virus-virophage, or transpovirion) system described with them, as well as their function, makes them, together with the biological features of giant viruses, form the basis for discussing the existence of a fourth domain in addition to Bacteria, Archaea, and Eukaryota. The paper also presents the hypothetical possibility of using them as a vector for vaccine antigens.

The paper presents the problem of intestinal mucosa immunity in teleost fish. The immunity of the intestinal mucosa in teleost fish depends on the elements and mechanisms with different organizational/structural and functional properties than in mammals. The organization of the elements of intestinal mucosal immunitya in these animals is associated with the presence of immune cells that fulfil the functions assigned to the induction and effector sites of mucosal immunity in mammals; they are located at various histological sites of the mucosa - in the lamina propria (LP) and in the surface epithelium. The presence of mucosa-associated lymphoid tissue (MALT) has not been demonstrated in teleost fish, and the terminology used in relation to the structure and function of the mucosa immunity components in teleost fish is inadequate. In this article, we review the knowledge of intestinal mucosal immunity in teleost fish, with great potential for knowledge and practical applications especially in the field of epidemiological safety. We discuss the organization and functional properties of the elements that determine this immunity, according to current data and taking into account the tissue definition and terminology adopted by the Society for Mucosal Immunology General Assembly (13th ICMI in Tokyo, 2007)., Competing Interests: Declaration of competing interest The authors declare no confict of interest/competing interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Haematopoiesis in fish and mammals is a complex process, and many aspects regarding its model and the differentiation of haematopoietic stem cells (HSCs) still remain enigmatic despite advanced studies. The effects of microenvironmental factors or HSCs niche and signalling pathways on haematopoiesis are also unclear. This review presents Danio rerio as a model organism for studies on haematopoiesis in vertebrates and discusses the development of this process during the embryonic period and in adult fish. It describes the role of the microenvironment of the haematopoietic process in regulating the formation and function of HSCs/HSPCs (hematopoietic stem/progenitor cells) and highlights facts and research areas important for haematopoiesis in fish and mammals., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Stosik, Tokarz-Deptuła and Deptuła.)

The article presents the function of platelets in inflammation as well as in bacterial and viral infections, which are the result of their reaction with the endovascular environment, including cells of damaged vascular endothelium and cells of the immune system. This role of platelets is conditioned by biologically active substances present in their granules and in their specific structures - EV (extracellular vesicles)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Tokarz-Deptuła, Palma, Baraniecki, Stosik, Kołacz and Deptuła.)

Immunological memory can be regarded as the key aspect of adaptive immunity, i.e. a specific response to first contact with an antigen, which in mammals is determined by the properties of T, B and NK cells. Re-exposure to the same antigen results in a more rapid response of the activated specific cells, which have a unique property that is the immunological memory acquired upon first contact with the antigen. Such a state of immune activity is also to be understood as related to "altered behavior of the immune system" due to genetic alterations, presumably maintained independently of the antigen. It also indicates a possible alternative mechanism of maintaining the immune state at a low level of the immune response, "directed" by an antigen or dependent on an antigen, associated with repeated exposure to the same antigen from time to time, as well as the concept of innate immune memory, associated with epigenetic reprogramming of myeloid cells, i.e. macrophages and NK cells. Studies on Teleostei have provided evidence for the presence of immunological memory determined by T and B cells and a secondary response stronger than the primary response. Research has also demonstrated that in these animals macrophages and NK-like cells (similar to mammalian NK cells) are able to respond when re-exposed to the same antigen. Regardless of previous reports on immunological memory in teleost fish, many reactions and mechanisms related to this ability require further investigation. The very nature of immunological memory and the activity of cells involved in this process, in particular macrophages and NK-like cells, need to be explained. This paper presents problems associated with adaptive and innate immune memory in teleost fish and characteristics of cells associated with this ability., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Interferons (IFNs) are proteins of vital importance in the body's immune response. They are formed in different types of cells and have been found in fish, amphibians, reptiles and mammals. Two types of IFN have been found in ray-finned fish (Superclass: Osteichthyes, Class: Actinopterygii) so far, i.e. IFN type I (IFN I) and IFN type II (IFN II), while the presence of IFN type III (IFN III), which is found in phylogenetically older cartilaginous fishes, was not confirmed in this taxonomic group of vertebrates. Currently, type I IFN in Actinopterygii is divided into three groups, I, II and III, within which there are subgroups. These cytokines in these animals show primarily antiviral activity through the use of a signalling pathway JAK-STAT (Janus kinases - Signal transducer and activator of transcription) and the ability to induce ISG (IFN-stimulated genes) expression, which contain ISRE complexes (IFN-stimulated response elements). On the other hand, in Perciformes and Cyprinidae, it was found that type I/I interferons also participate in the antimicrobial response, inter alia, by inducing the expression of the inducible nitric oxide synthase (iNOS) and influencing the production of reactive oxygen species (ROS) in cells carrying out the phagocytosis process., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Red blood cells (RBCs)-erythrocytes-of Osteichthyes are primarily known for their involvement in the process of gas exchange and respiration. Currently, physiological properties of RCBs in fish should also include their ability to participate in defense processes as part of the innate and adaptive immune mechanisms. In response to viruses, bacteria, and fungi or recombinant nanoparticles, they can modulate expression of genes responsible for immune reactions, influence activity of leukocytes, and produce cytokines, antimicrobial peptides, and paracrine intercellular signaling molecules. Via the complement system (CR1 receptor) and owing to their phagocytic properties (erythrophagocytosis), RBCs of Osteichthyes can eliminate pathogens. In addition, they are probably involved in the immune response as antigen-presenting cells via major histocompatibility complex class II antigens., (Copyright © 2020 Stosik, Tokarz-Deptuła, Deptuła and Deptuła.)

Commensal Escherichia coli population is a dynamic structure which may be important in the pathogenesis of extraintestinal infections. The aim of this study was the comparison of genetic diversity of commensal E. coli isolates from two age group-adults and young children. E. coli strains were isolated on MacConkey agar and identified by biochemical tests. Determination of four major phylogenetic groups, identification of virulence genes and antimicrobial resistance determinants were performed by using multiplex or simplex PCR. Phenotypic analysis of resistance was based on disc-diffusion method. The prevalence of virulence genes was significantly higher among isolates from adults than from young children. Phylogroup B2 predominated among E. coli from adults, whereas phylogroup A was the most common in isolates from young children. The analyses of antimicrobial resistance revealed that resistance to at least one antimicrobial agent and multidrug-resistance were detected significantly more frequent in the isolates from adults than from young children. This study documented that the commensal E. coli isolates from adults showed greater genetic diversity than from young children and constitutes a substantial reservoir of the virulence genes typical for extraintestinal pathogenic E. coli ., Competing Interests: The authors declare no conflict of interest.

The prevalence of trimethoprim (TMP) and sulfamethoxazole (SMX) resistance in commensal E. coli from pigs was tested in this study. E. coli was derived from three groups of piglets in successive stages of metaphylactic therapy and from two groups of sows 10 and 18 weeks after the treatment. MIC values of TMP and SMX were determined for a total of 352 strains. The presence of resistance genes (dfrA1, dfrA5, dfrA7, dfrA12, dfrA17, sul1, sul2, sul3) and class 1 and 2 integron-associated dfrA gene cassettes was tested. Resistance to TMP was very high during the administration of the antimicrobial (from 97 to 100%) and amounted to 86% and 69% in the post-exposure period; MIC > 32 mg/L. The isolates from all groups of pigs were resistant to sulfamethoxazole, with MIC > 1028 mg/L. The dfrA1 and sul1 genes (as part of integrons) dominated in E. coli from piglets, but the dfrA12 and sul1 genes were prevalent in E. coli from sows. Coexistence of the different dfrA genes was detected in 71 isolates from all groups of swine. Transcription analysis revealed that most of these genes were not transcribed, particularly gene cassettes of class 1 integrons. The research revealed a high level of resistance associated with the metaphylactic treatment, persistence and circulation of resistance in bacterial populations. Diverse genetic background with multiple and not transcribed resistance genes was observed.

Cattle is a reservoir of potentially pathogenic E. coli, bacteria that can represent a significant threat to public health, hence it is crucial to monitor the prevalence of the genetic determinants of virulence and antimicrobial resistance among the E. coli population. The aim of this study was the analysis of the phylogenetic structure, distribution of virulence factors (VFs) and prevalence of antimicrobial resistance among E. coli isolated from two groups of healthy cattle: 50 cows housed in the conventional barn (147 isolates) and 42 cows living on the ecological pasture (118 isolates). The phylogenetic analysis, identification of VFs and antimicrobial resistance genes were based on either multiplex or simplex PCR. The antimicrobial susceptibilities of E. coli were examined using the broth microdilution method. Two statistical approaches were used to analyse the results obtained for two groups of cattle. The relations between the dependent (VFs profiles, antibiotics) and the independent variables were described using the two models. The mixed logit model was used to characterise the prevalence of the analysed factors in the sets of isolates. The univariate logistic regression model was used to characterise the prevalence of these factors in particular animals. Given each model, the odds ratio (OR) and the 95% confidence interval for the population were estimated. The phylogroup B1 was predominant among isolates from beef cattle, while the phylogroups A, B1 and D occurred with equal frequency among isolates from dairy cattle. The frequency of VFs-positive isolates was significantly higher among isolates from beef cattle. E. coli from dairy cattle revealed significantly higher resistance to antibiotics. Some of the tested resistance genes were present among isolates from dairy cattle. Our study showed that the habitat and diet may affect the genetic diversity of commensal E. coli in the cattle. The results suggest that the ecological pasture habitat is related to the increased spreading rate of the VFs, while the barn habitat is characterised by the higher levels of antimicrobial resistance among E. coli.

Type 1 fimbriae are one of the most important factors of Escherichia coli adaptation to different niches in the host. Our study indicated that the genetic marker--fimH gene occurred commonly in commensal E. coli derived from healthy humans but expression of the type 1 fimbriae was not observed. Identification of fim structural subunit genes (fimA-fimH) and recombinase fimE and fimB genes showed that many of the strains were carrying an incomplete set of genes and the genes expression study revealed that in strains with complete set of fim genes, the fimC gene, encoding the chaperone protein, was not expressed.

The aim of the study was to determine the influence of the presence or the absence of antibiotic input on the emergence and maintenance of resistance in commensal bacteria from food producing animals. The research material constituted E. coli isolates from two animal species: swine at different age from one conventional pig farm with antibiotic input in young pigs and from beef and dairy cattle originated from organic breeding farm. The sensitivity to 16 antimicrobial agents was tested, and the presence of 15 resistance genes was examined. In E. coli from swine, the most prevalent resistance was resistance to streptomycin (88.3%), co-trimoxazole (78.8%), tetracycline (57.3%) ampicillin (49.3%) and doxycycline (44.9%) with multiple resistance in the majority. The most commonly observed resistance genes were: bla(TEM) (45.2%), tetA (35.8%), aadA1 (35.0%), sul3 (29.5%), dfrA1 (20.4%). Differences in phenotypes and genotypes of E. coli between young swine undergoing prevention program and the older ones without the antibiotic pressure occurred. A disparate resistance was found in E. coli from cattle: cephalothin (36.9%), cefuroxime (18.9%), doxycycline (8.2%), nitrofurantoin (7.7%), and concerned mainly dairy cows. Among isolates from cattle, multidrug resistance was outnumbered by resistance to one or two antibiotics and the only found gene markers were: bla(SHV), (3.4%), tetA (1.29%), bla(TEM) (0.43%) and tetC (0.43%). The presented outcomes provide evidence that antimicrobial pressure contributes to resistance development, and enteric microflora constitutes an essential reservoir of resistance genes.

Commensal, intestinal E. coli microflora plays a role in maintenance of intestinal balance of the host, is responsible for defending against pathogenic E. coli. This study encompasses the analysis of BOX-PCR fingerprinting patterns, phylogenetic grouping and virulence genes prevalence among commensal E. coli isolates derived from healthy pigs. Altogether, 274 unique E. coli isolates were identified, 110 from weaned piglets (Piglets I and Piglets II) and 164 from adult sows (Sows I and Sows II). BOX-PCR analysis distinguished isolates from pigs in different age and indicated that during maturation the changes in E. coli microflora occurred. Phylogenetic grouping revealed significant differences between distribution of four phylogenetic groups among isolates derived from piglets and sows. In phylogenetic structure of isolates from the piglets group B1 prevailed significantly, while among isolates derived from the sows the majority of them were classified into phylogenetic group A. The identification of 17 virulence factors in E. coli isolates derived from healthy pigs was performed. Three of 13 intestinal (escV, ehxA, estII) and four extra-intestinal virulence genes (VGs) (hlyA, fimH, papA, sfaS) were detected in the porcine isolates. The percentage of VGs positive isolates among piglets is higher than among sows, moreover, the VGs occurring in E. coli isolates from piglets revealed greater diversity than that detected among isolates from sows.

Three hundred commensal Escherichia coli recovered from healthy herbivorous, carnivorous, and omnivorous mammals from one zoo were characterized for their phylogenetic origin, intestinal virulence gene (VG) prevalence, and genomic diversity. The phylogenetic structure of the E. coli (groups A, B1, B2, and D) from the herbivores was homogenous, with a prevailing representation of group B1. In the carnivores and omnivores, the phylogenetic diversity was species specific with a higher representation of group A compared to the herbivores. Of 16 intestinal VGs in the whole set, 8 were detected and they formed 13 VG profiles. In the herbivores, all the VG-positive isolates belonged to group B1 and harboured the genes eaeA, eastI, ehxA, stx1, and stx2, which separately or in combination formed 8 VG profiles. In the carnivores and omnivores, the VG-positive isolates frequently belonged to group A and harboured the estI and estII genes or a combination of eastI and estI, forming three VG profiles. Single genes cnf2, in group B2, and eastI, in group D, were found. Similarity analysis of pulsed-field gel electrophoresis (PFGE) patterns revealed closer relatedness between the isolates from carnivores and omnivores than those from herbivores. The comparison between the prevalence of phylogenetic groups and the phylogenetic origin of VG-positive isolates in the examined E. coli suggested, that E. coli from group B1 in herbivores and E. coli from group A rather than B1 in carnivores and omnivores are "best adapted" to the host organism. The groups revealed different preferences in the acquisition and maintenance of intestinal VGs.

The paper describes the prevalence of resistant strains within the genetic structure of E. coli (phylogenetic group A, B1, B2 and D). A total of 200 commensal E. coli strains have been derived from 10 species of healthy animals residing on ZOO Safari Park area, in Swierkocin, Poland. The phylogenetic structure of E. coli has been analysed with the use of a PCR-based method. The strains were tested in terms of their susceptibility to eight classes of antibiotics: aminoglycosides, penicillins, cephalosporins, tetracyclines, nitrofurans, sulphonamides, phinicols, and quinolones. The genetic structure of E. coli revealed a not uniform distribution of strains among the four phylogenetic groups with significantly numerous representation of groups A and B1. Resistant E. coli were found within each of the phylogenetic groups. Strains resistant to one class of antibiotics occurred significantly more frequently in phylogenetic groups B2 and D (potential pathogens), whereas strains resistant to more than one class of antibiotics belonged to phylogenetic groups A and B1 (typical commensals) in a prevailing number of cases.

The specific contribution of insulin and IGF-I receptors to IRS-protein activation remains elusive. We studied the signalling properties of AspB10-insulin, an analog with enhanced affinity for the IGF-I receptor, in comparison to native insulin using primary human skeletal muscle cells. In myoblasts regular insulin and AspB10-insulin were equipotent in stimulating the IRS cascade, whereas this analog induced a significantly higher Shc phosphorylation. Phosphorylation of IRS-1 in response to insulin was inhibited equally by blocking either the insulin or the IGF-I receptor. IRS-1 activation by AspB10-insulin was only inhibited by blocking the IGF-I receptor. IRS-2 phosphorylation induced by both insulin and AspB10-insulin was nearly insensitive to blocking the insulin receptor, being predominantly mediated by the IGF-I receptor. We conclude that in myoblasts IRS-2, but not IRS-1, functions as preferred substrate for the IGF-I receptor. These data suggest a specific role for IRS-2 in growth and differentiation of human skeletal muscle.

Protein kinase C-zeta (PKC-zeta) participates both in downstream insulin signaling and in the negative feedback control of insulin action. Here we used an in vitro approach to identify PKC-zeta phosphorylation sites within insulin receptor substrate 1 (IRS-1) and to characterize the functional implications. A recombinant IRS-1 fragment (rIRS-1(449)(-)(664)) containing major tyrosine motifs for interaction with phosphatidylinositol (PI) 3-kinase strongly associated to the p85alpha subunit of PI 3-kinase after Tyr phosphorylation by the insulin receptor. Phosphorylation of rIRS-1(449)(-)(664) by PKC-zeta induced a prominent inhibition of this process with a mixture of classical PKC isoforms being less effective. Both PKC-zeta and the classical isoforms phosphorylated rIRS-1(449)(-)(664) on Ser(612). However, modification of this residue did not reduce the affinity of p85alpha binding to pTyr-containing peptides (amino acids 605-615 of rat IRS-1), as determined by surface plasmon resonance. rIRS-1(449)(-)(664) was then phosphorylated by PKC-zeta using [(32)P]ATP and subjected to tryptic phosphopeptide mapping based on two-dimensional HPLC coupled to mass spectrometry. Ser(498) and Ser(570) were identified as novel phosphoserine sites targeted by PKC-zeta. Both sites were additionally confirmed by phosphopeptide mapping of the corresponding Ser --> Ala mutants of rIRS-1(449)(-)(664). Ser(570) was specifically targeted by PKC-zeta, as shown by immunoblotting with a phosphospecific antiserum against Ser(570) of IRS-1. Binding of p85alpha to the S570A mutant was less susceptible to inhibition by PKC-zeta, when compared to the S612A mutant. In conclusion, our in vitro data demonstrate a strong inhibitory action of PKC-zeta at the level of IRS-1/PI 3-kinase interaction involving multiple serine phosphorylation sites. Whereas Ser(612) appears not to participate in the negative control of insulin signaling, Ser(570) may at least partly contribute to this process.

The rep-PCR fingerprinting method, with the support of ERIC and REP primers, was used to analyse the genomic diversity of 93 E. coli strains isolated from lake water samples drawn at two different depths. The applied UPGMA for DNA analysis did not reveale any genomic similarities between the 48 E. coli strains derived from the subsurface-zone water and the 43 of the bottom-zone water. The considerable genomic diversity of the E. coli of the surface zone was expressed as a dendrogram in the form of 8 similarity groups comprising strains isolated from samples drawn over one month. The bottom-zone strains, which display a lesser degree of genomic diversity (5 similarity groups), showed distinct common features in their DNA fingerprints. In the similarity dendrogram for the bottom-zone, strains derived in different months of sampling were segregated into the same similarity groups. Applying REP primers in rep-PCR generates more complex fingerprints increasing the discriminatory power of the analysis, whereas the ERIC primer generates less complex fingerprint patterns, and is thus clearer to interpret.

The authors present results of serological examination in 275 pheasants (Phaisanus colchicus) and 273 pigeons (Columba livia f. domestica) for the presence of Chlamydophila (Ch) psittaci IgG antibodies. Using micromethod of complement fixation (CF) test with genus-specific antigen Ch. psittaci (Bioveta, Ivanovice na Hané, Czech Republic), the seropositivity in pheasants oscillated between 31.5-40.4 %. No clinical signs of chlamydiosis were detected in pheasants under study. The seropositivity in pigeons ranged between 33.1-85.1%. Total 77.1% positivity with maximal 1:1024 antibody titre was found in 83 pigeons caught in April 2000, while, in June 2000 positivity was 41.0% with maximum titre 1: 512. Similarly, in the year 2001 the seropositivity in the group of 74 pigeons trapped in April reached up to 85.1% with the highest titre 1:1024 and in the pigeons trapped in June positivity decreased to 33.3% with the titer 1:256. These results prove an acute form of chlamydiosis and suggest that pigeons in spring time are an especially significant source of chlamydiosis for the human and animal population.

In the Slovak Republic, in 1966-2000, 37,275 blood sera of cattle were investigated for the presence of antibodies against Chlamydophila abortus using the method of complement fixation. The antibody occurrence had following tendency: in 1996--3.72%; 1997--10.02%; 1998--9.15%; 1999--15.99%; 2000--9.51% of the tested sera contained the antibodies. In most cases, antibodies in low titres, 1:32-1:64, were detected. Positive serological reactions at such serum dilutions are not indicative of the clinical disease of cattle; they reflect an immune response of the host organism following contact with the Chlamydophila abortus antigen. The chlamydial antibody titres of 1:256, which were confirmed in 1998-1999, indicate the chlamydial infections.

The paper presents usefulness of application of the PCR-based fingerprinting method, which uses enterobacterial repetitive intergenic consensus primers ERIC (rep-PCR (ERIC)) in analysing and characterising Escherichia coli population in the water environment. 46 E. coli isolates of homogenous biochemical properties were analysed. The received results prove considerable genomic diversity among the analysed isolates. The used technique has turned to be a reproducible and rapid method with a considerable differentiation power. The introductory research has revealed that the technique may be successfully used in qualitative research, for intra-species differentiation of microorganisms occurring in water environment.

The studies were performed on rabbits preimmunized with killed Chlamydia psittaci antigen (Czech isolate). In the blood of the animals nitrotetrazolium blue reduction test (spontaneous and stimulated) was performed, coefficient of polymorphonuclear cell metabolic activity in NBT test was calculated and myeloperoxidase activity was estimated, haematologic parameters were established and antibodies to Chlamydia psittaci were searched for using complement fixation test. The animals were subjected to clinical examination and their housing was tested for its zoohygienic standard. Analysis of the results demonstrated decreased activity of polymorphonuclear cells 3 to 4 weeks before appearance of anti-Chlamydia antibodies, as detected by complement fixation test.