Background: Salmonella typhi (S.typhi) is the major cause of human typhoid fever outbreaks. In fact, there were various typhoid fever outbreaks that occurred in China, and India that was caused by S.typhi strain without Vi antigen. Objective: To determine whether the S.typhi strains with mutation of gene encoding Vi antigen exists in Vietnam and the rate of mutation (if they exists). Subject and methods: 450 S.typhi isolates were collected in the Northern, Central and Southern Region of Vietnam during 1995 and 2005. The isolates were analyzed by the PCR method in order to detect mutants by using 2 primer pairs of tviB and DE. Results and Conclusion: There was no clear evidence on the relationship between the widely used Typhi Vi vaccine in Vietnam and the existence and spread of the mutation of gene encoding Vi antigen of S.typhi. 30 out of 450 isolates mutated losing the gene encoding of Vi antigen, making it 6.67%. These isolates were spread out between 1995 and 2005 throughout the Northern, Central and Southern Regions of Vietnam, with a peak in 1999. A noteworthy point was the rate of mutation of S.typhi losing the gene encoding of Vi antigen in Vietnam during the period of study. However, the mutation rate of S.typhi in Vietnam was still higher than the ratio of similar mutations being published in the other countries worldwide and higher than the recommended level of the World Health Organization.
gene mutation ; Salmonella typhi

Introduction: Mycobacterium tuberculosis resists rifampicin (RIF) because of mutations in the rpoB (the p subunit of RNA polymerase) gene, mostly in the 81 bp region. \r\n', u'Objectives: Identify the frequency and characteristics relative to drug - resistant rpoB gene mutation in RIF - resistant M. tuberculosis strains. \r\n', u'Subjects and method: 40 M. tuberculosis strains including 11 RIF - sensitive strains and 29 RIF - resistant strains. Some bio molecular techniques were used such as extracting mycobacterial DNA, PCR, cloning, sequencing and analyzing mutation related RIF - resistance on rpoB gene. \r\n', u'Results: No mutation was found on the 81 bp region of rpoB gene of the RIF - sensitive M. tuberculosis strains. The rate of mutation on rpoB gene of 29 RIF - resistant M. tuberculosis strains is 96.6%. We found 12 mutation codon positions on the 81 bp region of the rpoB gene, and the mutation codon positions with high frequency were 531 (51.7%) and 526 (31%). The mutation position found in only one strain is codon 519 (3.4%) but not found in other reports. There are 15 types of drug resistant mutations in which TCG531 TCG is the most common with 50%. Multi - drug resistance was seen in mutable and none mutable cases, with all codon positions and mutable forms. \r\n', u'Conclusion: No mutation was found on the 81 bp region of the rpoB gene of RtF - sensitive M. tuberculosis strains. The rate of mutation on the rpoB gene of RIF - resistant M. tuberculosis strains is 96.6%. The new mutation position found is codon 519. The mutation on the rpoB gene does not determine the multi - drug resistance of M. tuberculosis. \r\n', u'
Mutation ; rpoB gene ; Rifampicin - resistant M. tuberculosis

Mantle cell lymphoma(MCL) is an independent uncommon subtype of B-cell non-Hodgkin's lymphoma (NHL) according to World Health Organization classification of hematopoietic and lymphoid tissue tumors. The genetic hallmark of MCL is the chromosomal translocation t(11;14)(q13;q32) that leads to upregulation of cyclin D1, an important regulator of the G(1) phase in the cell cycle. This genetic aberration is virtually present in all cases of MCL. It is characterized by distinct clinical features and outcome which is affected by a series of additional genetic aberration including the genomic guardian-P53 gene. This article reviews the effects of P53 gene aberrations including P53 deletion, mutation and their mutual relationship in MCL, and novel therapeutic regimens for MCL patients with P53 aberrations.
Gene Deletion ; Genes, p53 ; Humans ; Lymphoma, Mantle-Cell ; genetics ; Mutation

Obesity is a major risk factor for lifestyle-related diseases and its prevention is essential in terms of public health. Body weight is influenced by a genetic predisposition as well as food intake, and exercise. In about 30% of the Japanese, a specific mutation [codon 64 TGG (Trp) →CGG (Arg)] of β3-adrenergic receptor gene is observed. The basal metabolic rate is about 200 kcal/day lower in the individuals with this type of mutation than in those without. We conducted a weight loss program which included analysis of β3-adrenergic receptor gene polymorphism, monitoring of eating behavior, and promotion for lifestyle modifications by public health nurses. The subjects for analyses were 39 Japanese men (mean age 37.8±8.6 years) and six Japanese women (46.8±6.4 years), with body mass index (BMI) over 24. They had not been receiving medical treatment for lifestyle-related diseases. The ratio of the normal group (no mutation at the specific site of β3-adrenergic receptor gene) to the mutation group were 73% to 27%. After we explained the results of the genetic testing to the participants, public health nurses encouraged them to change their lifestyle and provided dietary guidance. After 3 and 8 months intervention, reductions in BMI were observed 75% and 57% of the subjects in the normal group, and 92% and 67% of the subjects in the mutation group, respectively. At any time point, the changes were not statistically significant between the normal and mutation groups. Behavior modification was observed 49% of the subjects in the normal group and 75% in the mutation group. More than 80% of the participants were of the opinion that the genetic testing had been useful for them to reconsider their health status.
Mutation ; Receptors, Adrenergic ; Life Style ; Public health service ; gene polymorphism

OBJECTIVETo study the frequency distribution of flavin-containing monooxygenase 3 (FMO3) mutant alleles in 28 populations originating from 24 ethnic minorities in Yunnan of China.

METHODSFMO3 genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTSThe average frequencies of FMO3/Stop(148), FMO3/Lys(158) and FMO3/Gly(308) were 0.395(0.174-0.803), 0.208 (0.056-0.414), 0.046(0-0.217), respectively. The frequencies of FMO3/Gly(308) in Blang, Huayaodai, Shuidai, Zhuang, De'ang, Jingpo, Nu and Hui populations were null.

CONCLUSIONIt was found that the frequencies of FMO3 mutant alleles varied not only in different ethnic groups, but also in different populations that stemmed from the same ethnic group.

Directed evolution is a cyclic process that alternates between constructing different genes and screening functional gene variants. It has been widely used in optimization and analysis of DNA sequence, gene function and protein structure. It includes random gene libraries construction, gene expression in suitable hosts and mutant libraries screening. The key to construct gene library is the storage capacity and mutation diversity, to screen is high sensitivity and high throughput. This review discusses the latest advances in directed evolution. These new technologies greatly accelerate and simplify the traditional directional evolution process and promote the development of directed evolution.
Base Sequence ; Directed Molecular Evolution ; Gene Library ; Mutation ; Proteins/genetics*

Adenine ; Animals ; Gene Editing ; Mice ; Mutation ; Myotonic Dystrophy ; genetics ; Rats

Gene editing technology is a genetic operation technology that can modify the DNA sequence at the genomic level. The precision gene editing technology based on CRISPR/Cas9 system is a gene editing technology that is easy to operate and widely used. Unlike the traditional CRISPR/Cas9 system, the precision gene editing technology can perform site-directed mutation of genes without DNA template. This review summarizes the recent development of precision gene editing technology based on CRISPR/Cas9, and prospects the challenges and opportunities of this technology.
Gene Editing ; CRISPR-Cas Systems/genetics* ; Mutation ; Genome

OBJECTIVETo explore the correlation between homozygous deletions and mutation of p16 gene and the carcinogenesis and progression of squamous cell carcinoma of buccal mucosa.

METHODSThirty buccal cancers, 10 leukoplakias and 8 buccal mucosas were involved. DNA was extracted from the tissues. PCR was used to analyses homozygous deletion of p16 gene. PCR-SSCP-DNA sequencing was performed to detect the point mutation of p16 gene. Immunohistochemical techniques were used to detect the expression of P16 protein.

RESULTSGene deletions and point mutations were not found in leukoplakia and normal buccal mucosa. Gene deletions were found in 7 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (23.3%), while point mutations were found in 5 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (16.7%). Sequencing analysis showed that 5 cases point mutations were missense mutations, occurred on exon 2. Three cases occurred in the same point, codon 99 (GAT --> AAT). The result of immunohistochemical stains showed that 11 out of 12 cases gene inactivation did not expressed P16 protein.

CONCLUSIONHomozygous deletion and point mutation of p16 were the main pattern of gene inactivation in squamous cell carcinoma of buccal mucosa. There was a closely correlation between p16 gene inactivation and the carcinogenesis of squamous cell carcinoma of buccal mucosa.

BACKGROUND: Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous disorder. Connexin32 (Cx32) gene mutations on Xq13.1 cause the X-linked form of CMT disease, and PMP22 gene duplication on 17p11.2-p12 causes CMT1A. The aim of the present study is to determine the clinical and electrophysiological characteristics between X-linked CMT patients with Cx32 missense mutations and CMT1A patients with PMP22 duplications. METHODS: We screened for 17p11.2-p12 duplication, and for point mutations in Cx32 genes of 48 Korean CMT families. Both neurological examination and nerve conduction studies were performed in all patients. RESULTS: Frequency of CMTX (6.3%) in our study was similar to Japanese, and was lower than those in European peoples. CMTX patients displayed no man-to-man transmission, and had cranial nerve involvement. CMTX patients showed more wide range of motor and sensory nerve conduction velocities than CMT1A patients. We found one family with axonal neuropathy and two families with demyelinating neuropathy in CMTX patients. CONCLUSIONS: Our findings suggest that mutations in Cx32 are probably less frequent in Asian CMT patients than European patients, and CMTX neuropathy is intermediary between CMT1 and CMT2. In addition, inheritance pattern and cranial nerve involvement are useful in differentiating CMTX from CMT1A with duplication.
Asian Continental Ancestry Group ; Axons ; Cranial Nerves ; Gene Duplication ; Humans ; Inheritance Patterns ; Mutation, Missense* ; Neural Conduction ; Neurologic Examination ; Point Mutation