Integrated analysis of recombinant BPV-1 L1 protein for the production of a bovine papillomavirus VLP vaccine.

Bovine papillomatosis is an infectious disease that is caused by bovine papillomavirus (BPV), which results in important economic losses. However, no BPV vaccines or effective treatment methods are commercially available to date. Moreover, the absence of papillomavirus replication in vitro makes the use of recombinant protein a promising candidate for vaccine formulations. Hence, we developed an integrated study on the L1 capsid protein of BPV-1, obtained from a bacterial expression system, regarding its purification, biosafety, thermostability and immunogenicity. The results indicated an absence of genotoxicity of the purified recombinant L1 protein, ß-sheet prevalence of secondary structure folding, protein stability under high temperatures as well as the presence of capsomeres and VLPs. In addition, preliminary experimental vaccination of calves showed the production of specific antibodies against BPV-1 L1.

Genetics and metabolic deregulation following cancer initiation: A world to explore.

Cancer is a group of highly complex and heterogeneous diseases with several causes. According to the stochastic model, cancer initiates from mutation in somatic cells, leading to genomic instability and cell transformation. This canonical pathway of carcinogenesis is related to the discovery of important mechanisms that regulate cancer initiation. However, there are few studies describing genetic and metabolic alterations that deregulate transformed cells, resulting in epithelial-mesenchymal transition (EMT) and its most dramatic consequence, the metastasis. This review summarizes the main genetics and metabolic changes induced by reactive oxygen species (ROS) that lead to EMT.

Using the comet and micronucleus assays for genotoxicity studies: A review.

Physical, chemical and biological agents can act in the DNA, resulting in mutation involved in cancer. Thus, genotoxic tests are required by regulatory agencies in order to evaluate potential risk of cancer. Among these tests, the comet assay (CA) and micronucleus assay (MNA) are the most commonly used. However, there are different protocols and recommendations already published. This is the first review, after the inclusion of CA in S2R1 guidance and OECD 489, which summarizes the main technical recommendations of both CA and MNA.

Mutagenic Potential ofBos taurus Papillomavirus Type 1 E6 Recombinant Protein: First Description.

Bovine papillomavirus (BPV) is considered a useful model to study HPV oncogenic process. BPV interacts with the host chromatin, resulting in DNA damage, which is attributed to E5, E6, and E7 viral oncoproteins activity. However, the oncogenic mechanisms of BPV E6 oncoprotein per se remain unknown. This study aimed to evaluate the mutagenic potential of Bos taurus papillomavirus type 1 (BPV-1) E6 recombinant oncoprotein by the cytokinesis-block micronucleus assay (CBMNA) and comet assay (CA). Peripheral blood samples of five calves were collected. Samples were subjected to molecular diagnosis, which did not reveal presence of BPV sequences. Samples were treated with 1 µg/mL of BPV-1 E6 oncoprotein and 50 µg/mL of cyclophosphamide (positive control). Negative controls were not submitted to any treatment. The samples were submitted to the CBMNA and CA. The results showed that BPV E6 oncoprotein induces clastogenesis per se, which is indicative of genomic instability. These results allowed better understanding the mechanism of cancer promotion associated with the BPV E6 oncoprotein and revealed that this oncoprotein can induce carcinogenesis per se. E6 recombinant oncoprotein has been suggested as a possible vaccine candidate. Results pointed out that BPV E6 recombinant oncoprotein modifications are required to use it as vaccine.

Detection of bovine respiratory syncytial virus in experimentally infected balb/c mice.

The present study used an RT-nested-PCR and an immunohistochemistry assay to detect bovine respiratory syncytial virus in tissues from experimentally infected balb/c mice. As a first step, Chicken Embryo Related (CER) cell monolayers infected with the BRSV-25-BR strain isolated in Brazil were used for antigen production. Then, the infected lung and tracheal tissues of female balb/c mice were collected on 3, 5, 7 and 10 days post-infection and submitted to both techniques. Primers specific to F and G genes that amplify fragments of 481 bp and 371 bp, respectively, were used. The BRSV detection was not successful in all of the animals tested. The genomic fragment of the G gene from the organs of some infected mice on all analyzed post-infection days was amplified. However, in the RT-nested-PCR corresponding to the F gene, it was not possible to observe any amplified fragment. This was probably due to the higher sensitivity of the developed technique to amplify the fragment corresponding to the G gene compared to the F gene. Moreover, only three of the lungs collected five days post-infection were positive by immunohistochemistry. To the author's knowledge, this is the first study reporting bovine respiratory syncytial virus detection in balb/c mice after experimental inoculation.