RESUMO
Amphibian secretion is an important source of bioactive molecules that naturally protect the skin against noxious microorganisms. Collectively called antimicrobial peptides (AMPs), these molecules have a wide spectrum of action, targeting viruses, bacteria and fungi. Like many membrane and secreted proteins, AMPs have cleavable signal sequences that mediate and translocate the nascent polypeptide chains into the endoplasmic reticulum. Although it is accepted that the signal peptides (SPs) are simple and interchangeable, there is neither sequence nor structure that is conserved among all gene families. They derived from a common ancestor but developed different traits as they adapt to distinct environmental pressures. The aim of this study was to provide anoverview of the diversity of SPs of the frog, taking into account reported cDNA sequences and the evolutionary relationship among them. We analysed more than 2000 records that reported the relative abundance, diversity and evolutionary divergence based on the peptide signals of frog AMPs. We conclude that the physical properties of the sequence are more important than the specific peptidesin AMP SPs. Since there is significant overlapping among related genera, differences in secretion from different peptide types should be regulated by additional levels, such as posttranscriptional modifications or 5-UTR sequences.
Assuntos
Proteínas de Anfíbios/genética , Anfíbios/genética , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/genética , Bactérias/metabolismo , Sinais Direcionadores de Proteínas/genética , Pele/metabolismo , Proteínas de Anfíbios/metabolismo , Anfíbios/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismoRESUMO
It remains unknown whether human papillomaviruses (HPVs) in semen affect sperm DNA integrity. We investigated whether the presence of these viruses in semen was associated with an elevated sperm DNA fragmentation index. Semen samples of 22 normozoospermic patients undergoing infertility treatment, nine fertile donors and seven fertile men with a risk of HPV infection (genital warts or condylomas) were included in the study. The samples were examined by an INNO-LiPA test PCR-based reverse hybridisation array that identifies 28 types of HPVs as simple or multiple infections. Sperm DNA integrity was determined by sperm chromatin dispersion assay (SCD). Our preliminary findings demonstrate an increase in HPV infection in infertile men with respect to fertile men. However, the sperm DNA fragmentation index was not increased in semen containing these viruses.
Assuntos
Fragmentação do DNA , DNA , Papillomaviridae/isolamento & purificação , Sêmen/virologia , Espermatozoides/virologia , Cromatina/metabolismo , Humanos , Masculino , Sêmen/metabolismo , Espermatozoides/metabolismoRESUMO
BACKGROUND: XRCC1 (X-ray repair cross-complementing group 1) plays a central role in the DNA base excision repair mechanism. Single nucleotide polymorphisms (SNPs) in the XRCC1 gene are thought to modulate DNA repair capacity and have been linked to cancer risk in several studies. MATERIALS AND METHODS: We conducted a case-control study comprising 217 cervical samples, including 103 cervical carcinomas and 114 normal tissue samples. Cervical samples were genotyped for two XRCC1 SNPs (Arg194Trp and Arg399Gln) by PCR-RFLPs. RESULTS: Subjects carrying heterozygous Arg399Gln or the combined Gln399Gln + Arg399Gln variant genotypes had a significantly reduced risk for cervical cancer development. In addition, the 194Arg-399Gln haplotype was also found to be associated with a decreased risk for cervical carcinoma. CONCLUSION: Our findings suggest that XRCC1 genotypes and haplotypes contribute in reducing the risk for cervical cancer development. Furthermore, genetic susceptibility conferred by Arg399Gln polymorphism operates independently of human papillomavirus infection of cervical tissue.
Assuntos
Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Neoplasias do Colo do Útero/genética , Adulto , Alelos , Argentina , Estudos de Casos e Controles , Feminino , Frequência do Gene , Genótipo , Haplótipos , Humanos , Pessoa de Meia-Idade , Papillomaviridae/genética , Infecções por Papillomavirus/genética , Risco , Neoplasias do Colo do Útero/virologia , Proteína 1 Complementadora Cruzada de Reparo de Raio-XRESUMO
OBJECTIVE: The aim of the present work was to evaluate the presence of human papillomavirus genotypes in malignant and normal mucosa of the colon and rectum in order to determine if a relationship exists between HPV infection and colon neoplasms. MATERIALS AND METHODS: Thirty normal colon tissues and 54 sporadic adenocarcinomas were screened for HPV positivity using nested-PCR. Detection of viral types 6, 11, 16, 18, 33, 34 and 51 was performed by the LIS-SSCP (Low Ionic Strength-Single Strand Conformational Polymorphism) procedure. RESULTS: Significant differences in high risk HPV infection were found between normal samples and adenocarcinomas (P < 0.001). Among the cases, an inverse association between HPV infection and Dukes staging was also found (P = 0.020). Finally, there was no significant association between HPV and some classical clinicopathological features, although a gradient of infection form rectum to cecum was evident. CONCLUSION: The present study demonstrates that HPV may infect the glandular mucosa of the colon and suggests a possible association between HPV and colorectal cancer.
