Search Results

You are looking at 81 - 90 of 397 items for :

  • Molecular Biology x
Clear All
Open access

Edyta Świętoń and Krzysztof Śmietanka

Abstract

Introduction: The genomes of nine H5 subtypes of low pathogenic avian influenza virus (LPAIV) strains identified in wild birds in Poland between 2010 and 2015 were sequenced, and their phylogenetic relationship was determined.

Material and Methods: AIV genome segments were amplified by RT-PCR and the PCR products were sequenced using Sanger method. Phylogenetic trees were generated in MEGA6 software and digital genotyping approach was used to visualise the relationship between analysed strains and other AIVs.

Results: High genetic diversity was found in the analysed strains as multiple subgroups were identified in phylogenetic trees. In the HA tree, Polish strains clustered in two distinct subclades. High diversity was found for PB2, PB1, PA and NP, since 5-8 sublineages could be distinguished. Each strain had a different gene constellation, although relationship of as much as six out of eight gene segments was observed between two isolates. A relationship with poultry isolates was found for at least one segment of each Polish strain.

Conclusion: The genome configuration of tested strains indicates extensive reassortment, although the preference for specific gene constellation could be noticed. A significant relationship with isolates of poultry origin underlines the need for constant monitoring of the AIV gene pool circulating in the natural reservoir.

Open access

S. Cavers, C. Navarro, P. Hopkins, R. A. Ennos and A. J. Lowe

Abstract

The neotropical pioneer species Vochysia ferruginea is locally important for timber and is being increasingly exploited. The sustainable utilisation of this species would benefit from an understanding of the level and partitioning of genetic diversity within remnant and secondary regrowth populations. We used data from total genome (amplified fragment length polymorphism, AFLP) and chloroplast genome markers to assay diversity levels within seven Costa Rican populations. Significant chloroplast differentiation between Atlantic and Pacific watersheds was observed, suggesting divergent historical origins for these populations. Contemporary gene flow, though extensive, is geographically constrained and a clear pattern of isolation by distance was detectable when an inter-population distance representing gene flow around the central Costa Rican mountain range was used. Overall population differentiation was low (FST = 0.15) and within-population diversity high, though variable (Hs = 0.16-0.32), which fits with the overall pattern of population genetic structure expected for a widespread, outcrossed tropical tree. However genetic diversity was significantly lower and differentiation higher for recently colonised and disturbed populations compared to that at more established sites. Such a pattern seems indicative of a pioneer species undergoing repeated cycles of colonisation and succession.

Open access

Andrzej Kowalczyk, Kinga Urbaniak, Iwona Markowska-Daniel and Zygmunt Pejsak

Abstract

The aim of the study was to monitor genetic diversity and antigenic changes in the genome of influenza A(H1N1)pdm09 viral isolates detected during the post-pandemic period in Poland. Clinical specimens obtained from three suspected cases of influenza were analysed by sequencing. Among the differences identified in amino acids sequences, nine substitutions were located within the antigenic HA1 sites and in five residues forming receptor-binding pocket. The HA(D222G) mutation was shown in the isolate Swine/Poland/134312/12 obtained from a mild case of the disease. It must be emphasized that, in general, clinically mild cases are caused by the viruses in which that specific mutation, i.e. haemagglutinin (D222G), does not occur.

Open access

Wojciech Kozdru, Hanna Czekaj and Mariusz Lorek

Abstract

The aim of the study was to determine the aetiologic agent causing deaths in two flocks of Pekin ducklings at the age of 12 d in Poland. on the basis of clinical symptoms and pathological changes, viral hepatitis infection was suspected in the birds. During the necropsy, liver sections were collected, from which total cellular RNA was isolated. Then, real-time polymerase chain reaction (RT-PCR) was performed using primers complementary to the pre-S region of the duck hepatitis virus genome. In all liver samples, the presence of a 530 bp PCR product was detected. The RT-PCR demonstrated the presence of genetic material of duck hepatitis virus type 1 (DH type 1) in the examined ducklings.

Open access

Z. Mojžišová, P. Drzewnioková, E. Bocková, B. Vargová, V. Majláthová, I. Majláth, T. Csank and J. Pistl

Abstract

The tick-borne encephalitis virus (TBEV) and West Nile virus (WNV) are arboviruses of the genus Flavivirus in the family Flaviviridae. Their hosts are vertebratesof which rodents are the reservoirs of TBEV and birds are the reservoirs of WNV. Both viruses are transmitted from reservoirs to mammals by vectors. TBEV is transmitted by ticks (mostly Ixodes spp.) and WNV by mosquitoes (mostly Culex spp.). Both viruses are capable of infecting mammals, including man. TBEV and WNV are neurotropic, however infection is, in most cases, subclinical or accompanied by only moderate general signs. However, in some cases they can cause serious disturbances of the CNS. Our study focused on the detection of the genomes of TBEV and WNV in vectors by means of the reverse-transcription polymerase chain reaction (RT-PCR). The flavivirus genome was detected by means of oligonucleotides delineating the sequence in NS5 gene that encodes viral RNA-dependent RNA-polymerase. For the detection of TBEV, we used the oligonucleotide pair detecting the structural envelope protein. The positive samples were subjected to the sequence and phylogenetic analysis. The WNV was not detected in any of the pooled samples prepared from 616 mosquitoes captured in the vicinity of the village Drienovec, district Košice-surroundings. The investigation of 676 ticks demonstrated the presence of one strain of TBEV. One blood-fed I. ricinus female was obtained from a goat grazing in a pasture in the Dúbrava area close to Prešov. The genetic analysis revealed the presence of a strain close to the endemic strainsof TBEV Hypr and Neudörfl. The results of our study can become a motivation for additional studies in model locations oriented on ecology and circulation of these important zoonotic flaviviruses.

Open access

Mirosław P. Polak, Aleksandra Antos, Jerzy Rola and Jan F. Żmudziński

Abstract

Introduction: Bovine viral diarrhoea (BVD), caused by the bovine viral diarrhoea virus (BVDV), is one of the most important diseases of cattle worldwide. The purpose of the study was to determine the BVDV infection status in a dairy herd vaccinated against BVD. Before vaccination started in 2008, there had been no prior identification or the removal of the possible source of infection (persistently infected animals). It was expected that vaccination itself would enable the elimination of viral shedders on a long term basis. Material and Methods: Serological screening for antibodies against BVDV with determination for antibodies titres, BVDV antigen, and the presence of the viral genome with phylogenetic analysis of positive samples in the herd were performed, despite the lack of any clinical problems indicating possible presence of BVDV infection. Results: 19 individuals persistently infected with BVDV were identified among calves and heifers but not in adult cattle. All virus shedders were antibody negative and the genotype of isolated virus was BVDV-1b, indicating a single source of infection. The vaccine used in the herd was composed of BVDV-1a strain. In each of the tested cowsheds, antibody titres against BVDV-1b were higher than against BVDV-1a (median values). Conclusion: Despite a long-lasting vaccination programme and relatively high sequence homology of vaccinal and field strains of BVDV (83.6%), it was not possible to avoid transplacental infections of foetuses and the birth of persistently infected calves from vaccinated heifers although the protection against clinical disease was accomplished.

Open access

Andrzej Fitzner

Abstract

The field outbreak of RHD that occurred late summer 2012 on a small-scale rabbit-rearing operation in Poland and the usefulness of techniques for RHD virus diagnosis are described. During the epizootic, the overall mortality rate of rabbits older than two months was 77%. Eight liver specimens collected from dead unvaccinated rabbits (aged 3-5 months) underwent virological examinations. RHDV specific antigen was detected in two out of eight liver homogenates by haemagglutination (HA) test and ELISA, one of the two being negative in HA assay. However the presence of genetic material of RHD virus was confirmed by RT-PCR and real-time RT-PCR in all liver samples tested. Based on antigen reactivity in ELISA and sequencing of PCR amplicons of the VP60 gene, the RHDVa subtype strain was identified as the cause of infection. The partial genome sequence of a field isolate (STR 2012), comprising the C-terminus of the polymerase gene and the full capsid protein gene, revealed 91% nucleotide homology to reference FRG89 RHDV isolate and 97% to strain Triptis representing the RHDVa variant. Serological evidence of an RHD outbreak in the STR rabbit-rearing operation was confirmed in a serum sample collected from an unvaccinated surviving rabbit. A cross-reactivity examination of RHDV positive serum revealed a decrease in HI titre against the STR 2012 field antigen, and a decrease in the RHDVa control antigen as compared to classic RHDV.

Open access

Monika Olszewska-Tomczyk, Izabella Dolka, Edyta Świętoń and Krzysztof Śmietanka

Abstract

Introduction: Genotype VI of avian avulavirus 1 (AAvV-1) has pigeons and doves as its reservoir and is often termed pigeon paramyxovirus type-1 (PPMV-1). The pathogenesis of PPMV-1 infections in poultry is largely obscure. It is known that PPMV-1 requires a series of passages in chickens before it becomes adapted to gallinaceous poultry.

Material and Methods: Changes in the genome of PPMV-1 were analysed after serial passages in specific pathogen free (SPF) chickens, using high-throughput sequencing. Additionally, histopathological lesions induced by PPMV-1 in experimentally inoculated pigeons, chickens, and turkeys were evaluated.

Results: Following six passages of PPMV-1 in chickens, 10 nonsynonymous substitutions were found including one (in the NP protein) which dominated the genetic pool of viral quasispecies. Histopathological changes induced by the post-passage PPMV-1 strain were more prominent than changes wrought by the pre-passaged PPMV-1 strain and the lesions were most intense in pigeons followed by chickens and turkeys.

Conclusion: PPMV-1 is highly adapted to pigeons and passaging through chickens results in the acquisition of novel amino acids in the polymerase complex, which may alter the pathogenic potential of the virus.

Open access

Monica Licker, Roxana Moldovan, Elena Hogea, Delia Muntean, Florin Horhat, Luminița Baditoiu, Alexandru Florin Rogobete, Emil Tîrziu and Csilla Zambori

Abstract

The term biofilm designates an aggregate of microorganisms belonging to one or more species which adhere to various surfaces but also to each another. These microbial communities are included and interconnected within an organic structure known as slime, composed of protein substances, polysaccharides, and DNA.

The Center for Disease prevention and control considers infections with bacteria in biofilms among the 7 most important challenges which must be overcome in order to improve the safety of health services. The risk of microbial biofilm development exists for a long list of medical devices and equipment, as well as in certain diseases such as cystic fibrosis. An aggravating aspect is represented by the almost 1,000 times higher antimicrobial resistance of bacteria growing and multiplying within biofilms. Thus, in case of biofilm-infected medical devices, the resistance to antimicrobial treatments requires the removal of the device which essentially means the failure of the exploratory or therapeutic intervention in question.

The role of microbial biofilms in medical pathology is a subject that raises interest for both researchers and clinicians in order to establish new methods for prevention and treatment of biofilms. This paper is intended as an overview in the management of microbial biofilms, presenting future insights, with technological progress in microscopy, molecular genetics, and genome analysis. Therefore the present paper will focus on describing the mechanisms involved in biofilm development, biofilm related infections, methods of detection and quantification of microbial communities and therapeutical approaches.

Open access

X. He, F. Li, J. Shi and S. Gan

References B rondani , R. P. V., E. R. W illiams , C. B rondani and D. G rattapaglia (2006): A microsatellite-based consensus linkage map for species of Eucalyptus and a novel set of 230 microsatellite markers for the genus. BMC Plant Biol. 6 : 20. F aria , D. A., E. M. C. M amani , G. J. P appas , D. G rattapaglia (2011): Genotyping systems for Eucalyptus based on tetra-, penta-, and hexanucleotide repeat EST microsatellites and their use for individual fingerprinting and assignment tests. Tree Genet. Genomes 7 : 63–77. F aria , D. A