ABSTRACT
Levels of mtDNA(4977) deletions (DeltamtDNA(4977)) have been found to be lower in tumors than in adjacent non-tumoral tissues. In 87 cancer patients, DeltamtDNA(4977) was detected by multiplex polymerase chain reaction (PCR) amplification in 43 (49%) of the tumors and in 74 (85%) of the samples of non-tumoral tissues that were adjacent to the tumors. DeltamtDNA(4977) deletions were detected in 24% of the breast tumors, 52% of the colorectal tumors, 79% of the gastric tumors, and 40% of the head and neck tumors as compared with 77, 83, 100, and 90% of the adjacent respective non-tumoral tissues at the same DNA template dilution. Based on limiting dilution PCR of 16 tumors and their adjacent non-tumoral tissues, it was found that the amount of DeltamtDNA(4977) was 10- to 100-fold lower in the tumor than in the respective control non-tumoral tissues. Real-time PCR experiments were performed to quantify the number of DeltamtDNA(4977) deletions per cell, by determining the mitochondrial-to-nuclear DNA ratio. In all of the cases of breast, colorectal, gastric, and head and neck cancer the proportion of DeltamtDNA(4977) in tumors was lower than that of the respective non-tumoral tissue. Traces of DeltamtDNA(4977) in tumors were apparently due to contamination of tumor tissue with surrounding non-tumoral tissue, as evidenced by tumor microdissection and in situ PCR techniques, suggesting that tumors are essentially free of this mutation. Although the metabolic effect of DeltamtDNA(4977) may be minimal in normal (non-tumor) tissue, in tissue under stress, such as in tumors, even low levels of DeltamtDNA(4977) deletions may be intolerable.
Subject(s)
Female , Humans , Sequence Deletion/genetics , Mutation/genetics , Colorectal Neoplasms/genetics , Stomach Neoplasms/genetics , Breast Neoplasms/genetics , Head and Neck Neoplasms/genetics , Case-Control Studies , DNA, Mitochondrial/genetics , Polymerase Chain Reaction , Tumor Cells, CulturedABSTRACT
The salivary proteins of Anopheles darlingi Root, the principal vector of malaria in the Amazon Region, Brazil, were analyzed. Comparison of the protein profiles between adult males and females revealed that most of the polypeptides are present in both sexes, but female-specific polypeptides also were observed. SDS-PAGE analysis of sugar-fed female mosquitoes with ages varying from 1 to 10 d after adult emergence indicated that the proteins start to be accumulated in the first day of life and are present throughout the period analyzed. Analysis of blood-fed mosquitoes showed no differences in salivary proteins when compared with sugar fed ones, suggesting that there is no specific protein induced by blood. The protein profiles of the salivary glands dissected from wild-caught female mosquitoes from different geographical regions of Brazil were compared and some differences were observed.
