Avian leukosis virus (ALV), the prototypical alpharetrovirus, causes tumorigenesis, immunosuppression, and wasting disease in poultry. The ALV genus is classified into ten subgroups, which differ in their host range, cell tropism, and receptor usage. The subgroups A, B, K, and J cause significant economic losses worldwide. The most recently discovered subgroup, ALV-K, which is now widespread in China, has been shown to use the tva cell receptor and share it with ALV-A. However, the specific amino acid residues crucial for ALV-K host cell entry remain unknown. Using precise tva expression and chimeric tva receptors, we further elucidated the significance of the cysteine-rich domain in mediating interactions with both ALV-A and ALV-K. Through a comprehensive analysis of mutated tva receptor variants, we pinpointed tryptophan at position 33 (W33) as a pivotal amino acid residue essential for ALV-K virus binding and entry. Of note is the finding that the substitution of W33 induced resistance to ALV-K while preserving sensitivity to ALV-A. This study not only represents an advance in the understanding of the specificity of the tva receptor for ALV-K, but also offers a biotechnological strategy for the prevention of ALV-K infections in poultry.

• Klíčová slova
• avian leukosis virus, chicken, guineafowl, tva receptor,
• MeSH
• buněčné linie MeSH
• internalizace viru * MeSH
• kur domácí MeSH
• nemoci drůbeže virologie   MeSH
• přichycení viru * MeSH
• ptačí leukóza virologie   MeSH
• ptačí proteiny MeSH
• substituce aminokyselin MeSH
• virové receptory * genetika   metabolismus   chemie   MeSH
• virus ptačí leukózy * fyziologie   genetika   klasifikace   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ptačí proteiny MeSH
• Tva receptor MeSH Prohlížeč
• virové receptory * MeSH

Genetic editing of the germline using CRISPR/Cas9 technology has made it possible to alter livestock traits, including the creation of resistance to viral diseases. However, virus adaptability could present a major obstacle in this effort. Recently, chickens resistant to avian leukosis virus subgroup J (ALV-J) were developed by deleting a single amino acid, W38, within the ALV-J receptor NHE1 using CRISPR/Cas9 genome editing. This resistance was confirmed both in vitro and in vivo. In vitro resistance of W38-/- chicken embryonic fibroblasts to all tested ALV-J strains was shown. To investigate the capacity of ALV-J for further adaptation, we used a retrovirus reporter-based assay to select adapted ALV-J variants. We assumed that adaptive mutations overcoming the cellular resistance would occur within the envelope protein. In accordance with this assumption, we isolated and sequenced numerous adapted virus variants and found within their envelope genes eight independent single nucleotide substitutions. To confirm the adaptive capacity of these substitutions, we introduced them into the original retrovirus reporter. All eight variants replicated effectively in W38-/- chicken embryonic fibroblasts in vitro while in vivo, W38-/- chickens were sensitive to tumor induction by two of the variants. Importantly, receptor alleles with more extensive modifications have remained resistant to the virus. These results demonstrate an important strategy in livestock genome engineering towards antivirus resistance and illustrate that cellular resistance induced by minor receptor modifications can be overcome by adapted virus variants. We conclude that more complex editing will be necessary to attain robust resistance.

• MeSH
• CRISPR-Cas systémy MeSH
• editace genu MeSH
• fibroblasty virologie   metabolismus   MeSH
• kur domácí * virologie   MeSH
• kuřecí embryo MeSH
• molekulární evoluce MeSH
• nemoci drůbeže virologie   genetika   MeSH
• odolnost vůči nemocem genetika   MeSH
• proteiny virového obalu genetika   metabolismus   MeSH
• ptačí leukóza * virologie   genetika   MeSH
• virus ptačí leukózy * genetika   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• proteiny virového obalu MeSH

In the Mekong Delta region of Vietnam, small-scale chicken farming is common. However, high levels of disease or mortality in such flocks impair economic development and challenge the livelihoods of many rural households. We investigated 61 diseased small-scale flocks (122 chickens) for evidence of infection with 5 bacteria, 4 viruses, and helminths. Serological profiles (ELISA) were also determined against 6 of these pathogens. The aims of this study were the following: (1) to investigate the prevalence of different pathogens and to compare the probability of detection of bacterial pathogens using PCR and culture; (2) to investigate the relationship between detection of organisms in birds' tissues and the observed morbidity and mortality, as well as their antibody profile; and (3) to characterize risk factors for infection with specific viral or bacterial pathogens. We used PCR to test for viral (viruses causing infectious bronchitis [IB], highly pathogenic avian influenza [HPAI], Newcastle disease, and infectious bursal disease [IBD]) and bacterial pathogens (Mycoplasma gallisepticum, Pasteurella multocida, Avibacterium paragallinarum, and Ornithobacterium rhinotracheale [ORT]). The latter two were also investigated in respiratory tissues by conventional culture. Colisepticemic Escherichia coli was investigated by liver or spleen culture. In 49 of 61 (80.3%) flocks, at least one bacterial or viral pathogen was detected, and in 29 (47.5%) flocks, more than one pathogen was detected. A. paragallinarum was detected in 62.3% flocks, followed by M. gallisepticum (26.2%), viruses causing IBD (24.6%) and IB (21.3%), septicemic E. coli (14.8%), ORT (13.1%), and HPAI viruses (4.9%). Of all flocks, 67.2% flocks were colonized by helminths. Mortality was highest among flocks infected with HPAI (100%, interquartile range [IQR]: 81.6-100%) and lowest with flocks infected with ORT (5.3%, IQR: 1.1-9.0%). The results indicated slight agreement (kappa ≤ 0.167) between detection by PCR and culture for both A. paragallinarum and ORT, as well as between the presence of cestodes and ORT infection (kappa = 0.317). Control of A. paragallinarum, viruses causing HPAI, IBD, and IB, M. gallisepticum, and gastrointestinal helminths should be a priority in small-scale flocks.

• Klíčová slova
• Vietnam, bacterial pathogen, chicken, helminth, viral pathogen,
• MeSH
• bakteriální infekce epidemiologie   mikrobiologie   veterinární   MeSH
• kur domácí * MeSH
• morbidita MeSH
• mortalita MeSH
• nemoci drůbeže epidemiologie   mikrobiologie   parazitologie   virologie   MeSH
• parazitární nemoci u zvířat epidemiologie   parazitologie   MeSH
• polymerázová řetězová reakce veterinární   MeSH
• prevalence MeSH
• rizikové faktory MeSH
• tvorba protilátek MeSH
• virové nemoci epidemiologie   veterinární   virologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Vietnam epidemiologie   MeSH

Avian leukosis virus subgroup J (ALV-J) is an important concern for the poultry industry. Replication of ALV-J depends on a functional cellular receptor, the chicken Na+/H+ exchanger type 1 (chNHE1). Tryptophan residue number 38 of chNHE1 (W38) in the extracellular portion of this molecule is a critical amino acid for virus entry. We describe a CRISPR/Cas9-mediated deletion of W38 in chicken primordial germ cells and the successful production of the gene-edited birds. The resistance to ALV-J was examined both in vitro and in vivo, and the ΔW38 homozygous chickens tested ALV-J-resistant, in contrast to ΔW38 heterozygotes and wild-type birds, which were ALV-J-susceptible. Deletion of W38 did not manifest any visible side effect. Our data clearly demonstrate the antiviral resistance conferred by precise CRISPR/Cas9 gene editing in the chicken. Furthermore, our highly efficient CRISPR/Cas9 gene editing in primordial germ cells represents a substantial addition to genotechnology in the chicken, an important food source and research model.

• Klíčová slova
• CRISPR/Cas9 genome editing in chicken, Na+/H+ exchanger type 1, avian leukosis virus subgroup J, disease resilience in poultry, primordial germ cells,
• MeSH
• CRISPR-Cas systémy MeSH
• editace genu MeSH
• geneticky modifikovaná zvířata genetika   imunologie   virologie   MeSH
• kur domácí MeSH
• nemoci drůbeže genetika   imunologie   virologie   MeSH
• odolnost vůči nemocem MeSH
• ptačí leukóza genetika   imunologie   virologie   MeSH
• ptačí proteiny genetika   imunologie   MeSH
• sodíko-vodíkový výměnný transportér 1 genetika   imunologie   MeSH
• virus ptačí leukózy klasifikace   genetika   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ptačí proteiny MeSH
• sodíko-vodíkový výměnný transportér 1 MeSH

Infectious bursal disease (IBD) is an acute, highly contagious and immunosuppressive poultry disease. IBD virus (IBDV) is the causative agent, which may lead to high morbidity and mortality rates in susceptible birds. IBDV-pathogenesis studies have focused mainly on primary lymphoid organs. It is not known if IBDV infection may modify the development of the gut associated lymphoid tissues (GALT) as well as the microbiota composition. The aim of the present study was to investigate the effects of IBDV-infection on the bursa of Fabricius (BF), caecal tonsils (CT) and caecum, and to determine the effects on the gut microbiota composition in the caecum. Commercial broiler chickens were inoculated with a very virulent (vv) strain of IBDV at 14 (Experiment 2) or 15 (Experiment 1) days post hatch (dph). Virus replication, lesion development, immune parameters including numbers of T and B lymphocytes, macrophages, as well as the gut microbiota composition were compared between groups. Rapid IBDV-replication was detected in the BF, CT and caecum. It was accompanied by histological lesions including an infiltration of heterophils. In addition a significant reduction in the total mucosal thickness of the caecum was observed in vvIBDV-infected birds compared to virus-free controls (P < 0.05). vvIBDV infection also led to an increase in T lymphocyte numbers and macrophages, as well as a decrease in the number of B lymphocytes in the lamina propria of the caecum, and in the caecal tonsils. Illumina sequencing analysis indicated that vvIBDV infection also induced changes in the abundance of Clostridium XIVa and Faecalibacterium over time. Overall, our results suggested that vvIBDV infection had a significant impact on the GALT and led to a modulation of gut microbiota composition, which may lead to a higher susceptibility of affected birds for pathogens invading through the gut.

• MeSH
• cékum mikrobiologie   MeSH
• infekce viry z čeledi Birnaviridae patologie   veterinární   virologie   MeSH
• kur domácí MeSH
• lymfoidní tkáň mikrobiologie   patologie   MeSH
• mikrobiota * MeSH
• nemoci drůbeže patologie   virologie   MeSH
• virus infekční bursitidy drůbeže patogenita   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Clostridium perfringens-induced necrotic enteritis is generally controlled by antibiotics. However, because of increasing antibiotic resistance, other antibacterial agents are required, preferably ones that do not affect the beneficial intestinal microbiota of the host. This study evaluated the in vitro selective growth-inhibitory effect of 8-hydroxyquinoline (8HQ) on C. perfringens vs. bifidobacteria in a medium containing chicken ileal digesta. Prior to the experiments, the minimum inhibitory concentrations of 8HQ and penicillin G were determined by broth microdilution assay. The minimum inhibitory concentration values of 8HQ for C. perfringens were 16-32 times lower than the values for bifidobacteria. Treatment of autoclaved and non-autoclaved chicken ileal digesta with 8HQ showed a selective anticlostridial effect. After incubation of C. perfringens with autoclaved ileal digesta for 3 h, all 8HQ concentrations tested (32-2048 μg/mL) significantly reduced C. perfringens bacterial count. In contrast, the same treatment had no or only a slight effect on bifidobacteria counts. Unlike 8HQ, penicillin G did not exhibit any selectivity. Similar results were obtained after incubation for 24 h. In non-autoclaved ileal digesta, all 8HQ concentrations tested significantly reduced C. perfringens bacterial counts after incubation for 30 min and 3 h, while no effect was observed on bifidobacteria. These results suggest that 8HQ may serve as a prospective veterinary compound for use against necrotic enteritis in poultry.

• MeSH
• antibakteriální látky farmakologie   MeSH
• Bifidobacterium účinky léků   MeSH
• Clostridium perfringens účinky léků   MeSH
• ileum mikrobiologie   MeSH
• klostridiové infekce prevence a kontrola   veterinární   virologie   MeSH
• kur domácí mikrobiologie   MeSH
• nemoci drůbeže prevence a kontrola   virologie   MeSH
• oxychinolin farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• oxychinolin MeSH

UNLABELLED: Transformation of rodent cells with avian Rous sarcoma virus (RSV) opened new ways to studying virus integration and expression in nonpermissive cells. We were interested in (i) the molecular changes accompanying fusion of RSV-transformed mammalian cells with avian cells leading to virus rescue and (ii) enhancement of this process by retroviral gene products. The RSV-transformed hamster RSCh cell line was characterized as producing only a marginal amount of env mRNA, no envelope glycoprotein, and a small amount of unprocessed Gag protein. Egress of viral unspliced genomic RNA from the nucleus was hampered, and its stability decreased. Cell fusion of the chicken DF-1 cell line with RSCh cells led to production of env mRNA, envelope glycoprotein, and processed Gag and virus-like particle formation. Proteosynthesis inhibition in DF-1 cells suppressed steps leading to virus rescue. Furthermore, new aberrantly spliced env mRNA species were found in the RSCh cells. Finally, we demonstrated that virus rescue efficiency can be significantly increased by complementation with the env gene and the highly expressed gag gene and can be increased the most by a helper virus infection. In summary, Env and Gag synthesis is increased after RSV-transformed hamster cell fusion with chicken fibroblasts, and both proteins provided in trans enhance RSV rescue. We conclude that the chicken fibroblast yields some factor(s) needed for RSV replication, particularly Env and Gag synthesis, in nonpermissive rodent cells. IMPORTANCE: One of the important issues in retrovirus heterotransmission is related to cellular factors that prevent virus replication. Rous sarcoma virus (RSV), a member of the avian sarcoma and leukosis family of retroviruses, is able to infect and transform mammalian cells; however, such transformed cells do not produce infectious virus particles. Using the well-defined model of RSV-transformed rodent cells, we established that the lack of virus replication is due to the absence of chicken factor(s), which can be supplemented by cell fusion. Cell fusion with permissive chicken cells led to an increase in RNA splicing and nuclear export of specific viral mRNAs, as well as synthesis of respective viral proteins and production of virus-like particles. RSV rescue by cell fusion can be potentiated by in trans expression of viral genes in chicken cells. We conclude that rodent cells lack some chicken factor(s) required for proper viral RNA processing and viral protein synthesis.

• MeSH
• fúze buněk MeSH
• genové produkty env genetika   metabolismus   MeSH
• genové produkty gag genetika   metabolismus   MeSH
• křečci praví MeSH
• kur domácí MeSH
• nemoci drůbeže virologie   MeSH
• ptačí sarkom virologie   MeSH
• testy genetické komplementace MeSH
• transformované buněčné linie MeSH
• virová transformace buněk MeSH
• virus Rousova sarkomu genetika   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• genové produkty env MeSH
• genové produkty gag MeSH

Poultry Flavivirus (PF) was a recently emerged virus with high morbidity rates and mortality rates in China. It is the causative agent of egg drop syndrome at present. Development of the reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was the most efficient way to prevent and control the PF disease. The assay was performed at 64 °C for 45 min, using six specific primers that recognized eight targets of the PF E gene. The RT-LAMP assay, compared to conventional reverse transcription polymerase chain reaction, has 100-fold-greater sensitivity, with a detection limit of 1 × 10(-3) copies per μL RNA and no cross-reaction with poultry other viruses. The RT-LAMP assay is a valuable tool for detected PF without requiring any sophisticated equipment, and the detection has potential usefulness for clinical diagnosis in the field.

• MeSH
• diagnostické techniky molekulární metody   MeSH
• DNA primery genetika   MeSH
• drůbež MeSH
• Flavivirus genetika   izolace a purifikace   MeSH
• infekce viry z rodu Flavivirus diagnóza   veterinární   virologie   MeSH
• nemoci drůbeže diagnóza   virologie   MeSH
• proteiny virového obalu genetika   MeSH
• senzitivita a specificita MeSH
• techniky amplifikace nukleových kyselin metody   MeSH
• veterinární lékařství metody   MeSH
• virologie metody   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Čína MeSH
• Názvy látek
• DNA primery MeSH
• glycoprotein E, Flavivirus MeSH Prohlížeč
• proteiny virového obalu MeSH

• MeSH
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• geny src * MeSH
• heterografty MeSH
• integrace viru MeSH
• krysa rodu Rattus MeSH
• kur domácí virologie   MeSH
• nádorové buněčné linie MeSH
• nemoci drůbeže dějiny   virologie   MeSH
• periodika jako téma dějiny   MeSH
• proviry genetika   fyziologie   MeSH
• ptačí sarkom dějiny   virologie   MeSH
• transplantace nádorů MeSH
• virová transformace buněk MeSH
• virus Rousova sarkomu genetika   izolace a purifikace   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• autobiografie MeSH
• biografie MeSH
• historické články MeSH
• úvodníky MeSH
• Geografické názvy
• Československo MeSH
• Maryland MeSH

• O autorovi
• Svoboda, Jan
• Rous, Francis Peyton

The group of closely related avian sarcoma and leukosis viruses (ASLVs) evolved from a common ancestor into multiple subgroups, A to J, with differential host range among galliform species and chicken lines. These subgroups differ in variable parts of their envelope glycoproteins, the major determinants of virus interaction with specific receptor molecules. Three genetic loci, tva, tvb, and tvc, code for single membrane-spanning receptors from diverse protein families that confer susceptibility to the ASLV subgroups. The host range expansion of the ancestral virus might have been driven by gradual evolution of resistance in host cells, and the resistance alleles in all three receptor loci have been identified. Here, we characterized two alleles of the tva receptor gene with similar intronic deletions comprising the deduced branch-point signal within the first intron and leading to inefficient splicing of tva mRNA. As a result, we observed decreased susceptibility to subgroup A ASLV in vitro and in vivo. These alleles were independently found in a close-bred line of domestic chicken and Indian red jungle fowl (Gallus gallus murghi), suggesting that their prevalence might be much wider in outbred chicken breeds. We identified defective splicing to be a mechanism of resistance to ASLV and conclude that such a type of mutation could play an important role in virus-host coevolution.

• MeSH
• Alpharetrovirus genetika   fyziologie   MeSH
• genetická predispozice k nemoci * MeSH
• introny MeSH
• kur domácí genetika   metabolismus   virologie   MeSH
• molekulární sekvence - údaje MeSH
• nemoci drůbeže genetika   metabolismus   virologie   MeSH
• ptačí proteiny genetika   metabolismus   MeSH
• ptačí sarkom genetika   metabolismus   virologie   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční delece * MeSH
• sestřih RNA * MeSH
• virové receptory genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ptačí proteiny MeSH
• Tva receptor MeSH Prohlížeč
• virové receptory MeSH