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1

How RNA viruses exchange their genetic material

100%
Alejska M., Kurzynska-Kokorniak A., Broda M., Kierzek R., Figlerowicz M.
Acta Biochimica Polonica
|
2001
|
tom 48
|
nr 2
One of the most un usual fea tures of RNA vi ruses is their enor mous ge netic vari abil­ity. Among the dif fer ent pro cesses con trib ut ing to the con tin u ous gen er a tion of new vi ral vari ants RNA re com bi na tion is of spe cial im por tance. This pro cess has been ob­served for human, animal, plant and bacterial viruses. The collected data reveal a great sus cep ti bil ity of RNA vi ruses to re com bi na tion. They also in di cate that ge netic RNA re com bi na tion (es pe cially the nonhomologous one) is a major fac tor re spon si ble for the emer gence of new vi ral strains or spe cies. Al though the for ma tion and ac cu mu la tion of vi ral recombinants was ob served in nu­mer ous RNA vi ruses, the mo lec u lar ba sis of this phe nom e non was stud ied in only a few vi ral spe cies. Among them, brome mo saic vi rus (BMV), a model (+)RNA vi rus of­fers the best op por tu ni ties to in ves ti gate var i ous as pects of ge netic RNA re com bi na­tion in vivo. Unlike any other, the BMV-based system enables homologous and nonhomologous re com bi na tion stud ies at both the pro tein and RNA lev els. As a con se­quence, BMV is the vi rus for which the struc tural re quire ments for ge netic RNA re- com bi na tion have been most pre cisely es tab lished. Nev er the less, the pre vi ously pro­posed model of ge netic re com bi na tion in BMV still had one weak ness: it could not re­ally ex plain the role of RNA struc ture in nonhomologous re com bi na tion. Re cent discoveries concerning the latter problem give us a chance to fill this gap. That is why in this re view we pres ent and thor oughly dis cuss all re sults con cern ing nonhomologous recombination in BMV that have been ob tained un til now.
2
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Lymphoproliferation assay in cattle naturally infected with bovine leukemia virus [BLV] and bovine immunodeficiency virus [BIV]

86%
Stec J., Bicka L., Kozaczynska B., Kuzmak J.
Bulletin of the Veterinary Institute in Puławy
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2001
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tom 45
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nr 2
Lymphocyte proliferation rate was determined by ³H-thymidine incorporation assay after stimulation of peripheral blood mononuclear cells (PBMC) from BLV and BIV-infected cattle with mitogens: concanavalin A, phytohaemagglutitin, and pokeweed mitogen. BLV infection were associated with significant decrease in lymphocyte proliferation, as compared to uninfected animals. Co-infection with BIV strongly increased antimitotic influence of BLV, mainly in PL-animals. These results demonstrated that a function impairement of lymphocytes can be observed in the course of BLV and/or BLV/BIV infection.
3

Determination of lymphocyte subsets and PCNA activity in sheep experimentally infected with bovine leukemia virus [BLV]

72%
Szczotka M., Kawiak J., Winnicka A.
Bulletin of the Veterinary Institute in Puławy
|
2003
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tom 47
|
nr 1
4

Retroviral targeting of proliferating endothelial cells

72%
Gornikiewicz A., Zommer A., Jakesz R., Gnant M., Brostjan C.
Acta Biochimica Polonica
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2005
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tom 52
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nr 3
Tumor growth requires the formation of new blood vessels by endothelial cells. Thus, surface molecules - such as angiogenin receptors - that are selectively expressed on growing endothelium represent an attractive target for directed delivery of compounds to tumor tissue. We attempted to obtain genetically engineered retroviral vectors targeted to the endothelium by inserting the human angiogenin sequence into Moloney murine leukemia virus envelope glycoprotein. Abundant expression of the chimeric protein could be verified. However, while being selective for proliferating human endothelial cells, the recombinant retroviral particles displayed low transduction efficiencies and thus have to be further improved.
5
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Possibility of the presence of a sequence similar to bovine leukaemia virus genome in the genome of BLV-free cattle

72%
Grabek-Gawlowicz M., Gasowska U., Rulka J., Wojcierowski J.
Bulletin of the Veterinary Institute in Puławy
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2000
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tom 44
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nr 2
The purpose of this study was searching for sequences similar to bovine leukaemia virus genome in the genome of BLV-free cattle. The study was performed using PCR method and hybridisation. Products of amplification with starters specific for BLV genome was discovered. The presence of these sequences was confirmed by hybridisation with molecular probe complementary to BLV genome. It cannot be ruled out that these are endogenous sequences similar to bovine leukaemia virus in the genome of BLV-free cattle.
6

Retroviral vectors as tools for animal transgenesis

72%
Lisowski P., Kleczkowski M., Jakubczak A.
Advances in Agricultural Sciences
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2004
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tom 09
7

Presence of env-like sequences in Quercus suber retrotransposons

58%
Carvalho M., Ribeiro T., Viegas W., Morais-Cecilio L., Rocheta M.
Journal of Applied Genetics
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2010
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tom 51
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nr 4
The main difference between LTR retrotransposons and retroviruses is the presence of the envelope (env) gene in the latter, downstream of the pol gene. The env gene is involved in their infectious capacity. Here we report the presence of env-like sequences in the genome of Quercus suber (cork oak), one of the most economically important Portuguese species. These gene sequences were isolated through DNA amplification between RNaseH conserved motifs and 3' LTR, based on the structure of copia retrotransposons. Phylogenetic analysis revealed that almost all the clones isolated are clustered with Cyclops-2, a Ty3-gypsy element identified in Pisum sativum, except one clustered with gypsy and copia retroelements found in different species. This suggests the existence of a potential ancestral sequence of the env gene, prior to the separation of Ty3-gypsy and Tyl-copia retrotransposons. Additionally, the isolated env-like sequences showed 26-39% of homology with env-like sequences characterized in viruses. The origin of env-like sequences in retrotransposons from host plant taxa is discussed.
8

Decreased serum adenosine deaminase activities in Van cats with feline retroviruses infections

58%
Altug N., Yuksek N., Agaoglu Z. T., Ozkan C.
Medycyna Weterynaryjna
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2007
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tom 63
|
nr 02
184-186
This aim of the study was to determine the activity of ADA serum and isoenzyme in feline retroviral infections. The study involved 6 FeLV seropositive, 4 FIV seropositive and 10 healthy seronegative cats aged between 1-8 years. Haematological, serum enzyme acivity (AST; ALT; ALP; GGT) as well as ADA serum and isoenzyme activity were determined in all the cats. Haematological parameters were within the normal range except for the platelet count in FIV seropositive cats (p<0.05). Serum enzyme activity was unchanged except for the AST concentration in FeLV and FIV seropositive cats compared to the healthy subjects. ADA serum and ADA1 concentrations were lower in the seropositive group than in the seronegative group. However, the decrease in ADA serum and ADA1 concentrations in FIV seropositive cats (p<0.01) was more significant than that of FeLV seropositive cats (p<0.05). In conclusion, decreased ADA and ADA1 activity in feline retrovirus infections may be significant.
9

Flow cytometry determination of Bcl-2 expression in animals infected with bovine leukaemia virus

58%
Szczotka M., Buzala E., Deren W., Kubis P.
Bulletin of the Veterinary Institute in Puławy
|
2006
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tom 50
|
nr 1
10

Expression of bovine leukemia virus protein p24 in Escherichia coli and its use in the immunoblotting assay

58%
Bicka L., Kuzmak J., Kozaczynska B., Plucienniczak A., Skorupska A.
Acta Biochimica Polonica
|
2001
|
tom 48
|
nr 1
The gag gene encoded protein, p24 of bovine leukemia virus (BLV), was cloned and ex­pressed as thioredoxin-6xHis-p24 protein in Escherichia coli. The bacterial cells carrying plasmid pT7THis-p24 expressed the protein of 38 kDa that was detected by immuno­blotting analysis using anti-p24 monoclonal antibodies and sera from BLV infected cattle and sheep. The purified p24 fusion protein was shown to be sensitive and specific for de­tection of BLV antibodies in the infected cattle.
11

Human T cell leukemia virus type 1: the role of Tax in leukemogenesis

58%
Pise-Masison C. A., Jeong S. J., Brady J. N.
Archivum Immunologiae et Therapiae Experimentalis
|
2005
|
tom 53
|
nr 4
12

dUTP pyrophosphatase as a potential target for chemotherapeutic drug development

58%
McIntosh E. M., Haynes R. H.
Acta Biochimica Polonica
|
1997
|
tom 44
|
nr 2
Aberrant dUTP metabolism plays a critical role in the molecular mechanism of cell killing induced by inhibitors of dihydrofolate reductase and thymidylate synthase. While considerable effort has been directed towards discovering new, more potent inhibitors of these two enzymes, little attention has been given dUTP pyrophosphatase (dUTPase)--the key modulator of cellular dUTP levels--as a potential target for chemotherapeutic drug development. Recent studies have provided evidence that dUTPase is vital for cellular and, in some cases, viral DNA replication. Furthermore, some retroviruses encode dUTPases--a fact which suggests that cellular dUTP metabolism may be more important than previously realized. Here, we briefly review current knowledge of cellular and viral dUTPases and discuss the potential of these enzymes as targets for cancer chemotherapeutic and anti-viral drug development.
13

Retroviruses in autoimmune liver disease: genetic or environmental agents?

58%
Mason A. L., Hu L., Guo L., Garry R. F.
Archivum Immunologiae et Therapiae Experimentalis
|
1999
|
tom 47
|
nr 5
14

Application of PCR technique in diagnosis of small ruminant lentivirus infection in sheep and goats

58%
Gil A., Rola M., Kuzmak J.
Polish Journal of Veterinary Sciences
|
2006
|
tom 09
|
nr 4
Detection of small ruminant lentiviruses (SRLVs) in sheep and goats usually relies on serological testing. In this study, we evaluated semi-nested PCR and nested PCR techniques applied as a diagnostic tool for detection of maedi-visna virus (MVV) and caprine arthritis-encephalitis virus (CAEV) in naturally infected sheep and goats, respectively. The examination of 193 ovine and 85 caprine serum samples by the ELISA revealed the presence of specific antibodies in 133 (69%) and 18 (21.2%) animals, respectively. Presence of proviral DNA was manifested in 103 (53.4%) sheep and 12 (14.2%) goats. Despite the relatively lower sensitivity of PCR, the fact of detection of proviral DNA in 19 out of 60 ovine samples and 7 out of 67 caprine samples collected from animals previously negative by ELISA was noteworthy. In conclusion, the data demonstrated that combinations of both ELISA and PCR might afford optimal detection of SRLVs infection.
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