Fluorescent detection of point mutation via ligase reaction assisted by quantum dots and magnetic nanoparticle-based probes

A nanodiagnostic genotyping method was presented for point mutation detection directly in human genomic DNA based on ligase reaction coupled with quantum dots and magnetic nanoparticle-based probes.

Association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and gastric cancer and metastasis

HO-1 gene encodes heme oxygenase-1 enzyme that catalyzes the oxidation of heme to carbon monoxide (CO). It has also been suggested that cells could be protected by the enzyme against stress. A (GT) n dinucleotide repeat at HO-1 promoter is a polymorphic region and modulates gene transcription and associated with some of diseases. In this study, length of polymorphism GT tandem repeat has been determined and classified into two alleles short (≤28) and long (≥29). In present study, association between GT-repeat polymorphism at heme oxygenase-1 gene promoter and increased risk of gastric cancer and metastasis was investigated. Blood samples from 100 control individuals and 60 gastric cancer cases had taken. Genotypic frequencies of (GT) n repeat for samples were determined using PCR technique and polyacrylamide PAGE electrophoresis. At final, higher frequency alleles were sequenced. Our results show that S-allele is significantly higher in cases in comparison with control groups (p = 0/000, odds ratio (OR) = 4/154). It has been shown that individuals with S/S and S/L genotypes are at high risk of having gastric cancer (p = 0/000, OR = 3/789). Statistic data show association between SS genotype and risk of gastric cancer metastasis (p = 0.017, OR = 3.889). But, there is no significant association between clinicopathological characteristics of the patients and risk of gastric cancer metastasis (p > 0.05). Significant association was found between short allele (SS + SL genotypes) and risk of gastric cancer, and also strong association was found between SS genotype and risk of gastric cancer metastasis.

The influence of interstitial collagenase-1 genotype polymorphism on colorectal cancer risk in Iranian population

Interstitial collagenase-1 degrades a variety of extracellular matrix components. A single guanine insertion polymorphism in the promoter has been found that influences on the transcription and expression level of the gene. It is suggested that this polymorphism may enhance susceptibility to some types of cancer. Therefore, this case-control study evaluated the association of this genotype polymorphism with susceptibility to initiation and invasion of colorectal cancer. For this reason, whole blood samples were obtained from 150 CRC patients and 100 control subjects in Tehran. Genomic DNA was extracted and genotyped by PCR-RFLP method. We showed that 2G allele and 2G/2G genotype had higher frequencies in patients (60% and 39%, respectively) than in controls (47% and 23%, respectively). The CRC patients were divided into two groups: with metastasis (M+) and without metastasis (M-) groups. The 2G allele was more frequent in M+ group compared with control group. However, no significantly difference was observed between M-group and control (chi(2) = 0.48, P = 0.78 for 2G/2G genotype). Further stratification analyses showed that only gender (OR = 2.58, 95% CI = 0.89-7.52 for women and OR = 4.12, 95% CI = 1.62-10.42 for men) and smoking (OR = 3.03, 95% CI = 1.28-7.16 for non-smokers and OR = 4.09, 95% CI = 1.18-4.15 for smoker) may modify the risk of colorectal invasion related to 2G/2G genotype. Furthermore, individual with 2G/2G genotype seems to spread metastasis, 3 years earlier than those who were 1G/1G and 1G/2G. In conclusion, to our knowledge, the present epidemiological study for the first time indicates the relationship of 2G/2G genotype polymorphism with invasion risk of colorectal cancer in subgroups of gender and smoking, especially in smoker men.

Unequal sister chromatid exchange in the rDNA array of Saccharomyces cerevisiae

In the yeast Saccharomyces cerevisiae the nucleolar organiser region (NOR) is located on chromosome XII. It contains 100-200 copies of rDNA--a minimum of 20 rDNA genes in tandem--and is termed the RDN locus. Yeast cells may exist in either haploid or diploid form. There are two forms of life cycle: haploid and diploid cells double by mitosis, and diploid cells are reduced to the haploid state by meiosis. Diploid cells have two homologous chromosomes for each of the 16 chromosomes. They are usually of the same size. However, in this study it is shown that homologous chromosomes XII can become different in size due to unequal sister chromatid exchange during mitosis in 'old' cells.