Associations between cigarette smoking and mitochondrial DNA abnormalities in buccal cells

DNA alterations in mitochondria are believed to play a role in carcinogenesis and are found in smoking-related cancers. We sought to replicate earlier findings for the association of smoking with increased mitochondrial DNA (mtDNA) content in buccal cells and further hypothesized that there would be an increased number of somatic mtDNA mutations in smokers. Buccal cells and blood lymphocytes were studied from 42 healthy smokers and 30 non-smokers. Temporal temperature gradient electrophoresis screening and sequencing was used to identify mtDNA mutations. The relative mtDNA content was determined by real-time polymerase chain reaction. Assuming that mtDNA in lymphocytes represents the inherited sequence, it was found that 31% of smokers harbored at least one somatic mtDNA mutation in buccal cells with a total of 39 point mutations and 8 short deletions/insertions. In contrast, only 23% of non-smokers possessed mutations with a total of 10 point mutations and no insertions/deletions detected. mtDNA somatic mutation density was higher in smokers (0.68/10 000 bp per person) than in non-smokers (0.2/10 000 bp per person). There was a statistically significant difference in the pattern of homoplasmy and heteroplasmy mutation changes between smokers and non-smokers. Whereas non-smokers had the most mutations in D-loop region (70%), smokers had mutations in both messenger RNA encoding gene (36%) and D-loop region (49%). The mean ratio of buccal cells to lymphocytes of mtDNA content in smokers was increased (2.81) when compared with non-smokers (0.46). These results indicate that cigarette smoke exposure affects mtDNA in buccal cells of smokers. Additional studies are needed to determine if mitochondrial mutation assays provide new or complementary information for estimating cigarette smoke exposure at the cellular level or as a cancer risk biomarker

Genetic differences between strains of Biomphalaria glabrata (Planorbidae) that are susceptible and unsusceptible to schistosomiasis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Despite the implementation control programs, schistosomiasis continues to spread throughout the world. Among modern control strategies, vector control is currently being emphasized. Within this context, analysis of the genetic variability of intermediate host snails (Biomphalaria spp) is important because it allows identification of specific sequences of the genome of this mollusk related to susceptibility/resistance to Schistosoma mansoni infection. We investigated Brazilian albino (non-pigmented) and pigmented (wild type) strains of Biomphalaria glabrata; these strains differ in their susceptibility to S. mansoni infection. Genetic variability was studied by RAPD-PCR using different random primers. The electrophoretic patterns resulting from amplification showed specific polymorphic markers for the albino and pigmented strains of B. glabrata. This information will help in the identification and isolation of genes specifically related to susceptibility, demonstrating that RAPD-PCR is an appropriate and efficient methodological approach for analysis of the genetic variability of schistosomiasis vectors.9314501459Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Long-term performance deterioration models for semi-rigid asphalt pavement in cold region

As the demand for the semi-rigid asphalt pavement reconstruction and maintenance technologies is increasing in the seasonal cold regions, the pavement performance deterioration models are essential for the success of the reconstruction and maintenance projects. This study is carried out to develop the deterioration models based on the preliminary investigation results of typical successful maintenances. All critical technical indexes concerning the asphalt pavement maintenance were studied. By combining the engineering practices, a long-term performance database of the semi-rigid asphalt pavement was established through a large amount of survey data, and the related environmental parameters. Based on the database achieved, the deterioration models of the semi-rigid asphalt pavement performances were built via the statistical regression method. It is concluded that the proposed deterioration models were useful and practical for the establishment of the maintenance decision of the semi-rigid asphalt pavements