用庆大霉素抗性筛选法选育西罗莫司高产菌株

用紫外线对吸水链霉菌（Streptomyces hygroscopicus）NP03进行诱变，再采用庆大霉索抗性筛选法进行处理，剂量分别为0、0．01、0．03、0．05和0．08μg／ml，共获得113株抗性突变株，其中西罗莫司产量高于出发菌株的有51株，突变株NP03-74#的生产能力达到出发菌株的134％，且遗传特性稳定。     

Hereditary diffuse gastric cancer and E-cadherin: description of the first germline mutation in an Italian family.

AIMS: Germline mutation of the E-cadherin gene (CDH1) accounts for the Hereditary Diffuse Gastric Cancer (HDGC) syndrome. Fourteen pedigrees with Diffuse Gastric Cancer that fulfilled the International Gastric Cancer Linkage Consortium (IGCLC) criteria were selected and screened for CDH1 germline mutations. METHODS: The entire coding region of the CDH1 gene and all intron-exon boundaries were analyzed by direct sequencing in the 14 families fulfilling the IGCLC criteria. E-cadherin immunohistochemical expression was evaluated on tumour as well as normal formalin-fixed paraffin embedded tissues. RESULTS: A novel germline missense mutation was found. It was a single C-->T substitution in exon 8, resulting in a transition of CCG-->CTG (C1118T; Pro373Leu) demonstrated in the proband and her brother. At immunohistochemical analysis, the staining intensity was reduced and considered weakly positive (15%). CONCLUSIONS: The first CDH1 germline mutation of an Italian family is herein reported. The present missense mutation has never been described so far.     

遗传性非息肉病性结直肠癌

Hereditary non-polyposis colorectal cancer(HNPCC) is an autosomal-dominantly inherited disease which is associated with germline mutations in mismatch repair(MMR) genes and microsatellite instability (MSI). As an important clinical subtype of colorectal cancer, HNPCC is accounting for 5%～15% of colorectal cancer. It' s focus research of colon cancer and hereditary tumor currently because of the special genetic etiopathogenisis and the prominent clinical pathology characteristic.     

小儿热性惊厥研究

热性惊厥是小儿时期因体温升高诱发的一种特殊的癫痫综合征。研究发现其与遗传有关,有较明确的基因位点。机体细胞及体液免疫紊乱成为易复发的原因之一。在血生化方面,血清铁、钙的含量降低也是重要的易感因素。由于其对智能发育影响尚不确定,故预防性抗惊厥治疗尚需进一步探讨。     

遗传性痉挛性截瘫基因SPG3A的基因组结构和多态性分析

目的:分析遗传性痉挛性截瘫(HSP)SPG3A基因组结构,探讨部分正常人群SPG3A的基因多态性。方法:应用DNA序列测定对110个年龄大于60岁的正常人进行SPG3A/Atlastin基因多态分析。结果:在外显子2和外显子3的编码序列中有两处基因多态;内含子3,内含子4和内含子6上分别发现了一处基因多态。结论:正常个体的等位基因中发现只有2个编码序列多态性且为高度保留序列,其余3个均位于内含子上。对序列变异、多态性相对频率及SPG3A基因组结构的分析将有助于遗传性痉挛性截瘫疾病和其它轴突变性神经疾病的遗传分析。     

Frequent Genetic Instability in Small Intestinal Carcinomas

To determine whether genetic instability plays a part in the development of digestive tract carcinomas, we analyzed 3 microsatellite loci isolated from tumors and surrounding normal tissue samples obtained during surgery. The polymerase chain reaction (PCR) technique was used to assess differences between tumor and matched normal DNAs. Replication errors (RERs) were observed in 3 of the 29 cases (10%) of gastric carcinoma and in 11 of the 72 cases (15%) of colorectal carcinoma. None of the 13 (0%) esophageal carcinoma cases showed any RER, but 5 of the 11 cases of small intestinal carcinoma (45%) had RERs, a significantly frequent finding. These results suggest that genetic instability plays an important role in the pathogenesis of small intestinal carcinomas.     

Loss or Somatic Mutations of hMSH2 Occur in Hereditary Nonpolyposis Colorectal Cancers with hMSH2 Germline Mutations

Hereditary nonpolyposis colorectal cancer (HNPCC) is a major cancer susceptibility syndrome known to be caused by the inheritance of mutations in DNA mismatch repair genes, such as hMSH2, hMLH1, hPMS1 and hPMS2 . To investigate the role of genetic alterations of hMSH2 in HNPCC tumorigenesis, we analyzed 36 Japanese HNPCC kindreds as to hMSH2 germline mutations. Moreover, we also examined somatic mutations of hMSH2 or loss of heterozygosity at or near the hMSH2 locus in the tumors from the hMSH2 -related kindreds. Germline mutations were detected in five HNPCC kindreds (5/36, 14%). Among them, three were nonsense mutations, one was a frameshift mutation and the other was a mutation in an intron where the mutation affected splicing. Loss of heterozygosity in four and somatic mutations in one were detected among the eight tumors with hMSH2 germline mutations. All these alterations were only detected in genomic instability(+) tumors, i.e., not in genomic instability(-) ones, indicating that mutations of hMSH2 were responsible for at least some of the tumors with genomic instability. These data establish a basis for the presymptomatic diagnosis of HNPCC patients, and constitute further evidence that both DNA mismatch repair genes and tumor suppressor genes may share the same requirement, i.e., two hits are necessary to inactivate the gene function.     

hMLH1 and hMSH2 gene mutation in Brazilian families with suspected hereditary nonpolyposis colorectal cancer

Background The aim of this study was to search for mutations in the humanmutS homolog 2 (hMSH2) and humanmutL homolog 1 (hMLH1) genes in 25 unrelated Brazilian kindreds with suspected hereditary nonpolyposis colorectal cancer (HNPCC). Methods The families were grouped according to the following clinical criteria: Amsterdam I or II; familial colorectal cancer (CRC); an early age of onset of CRC in the proband only; or with at least one or two relatives who had HNPCC-related cancers; CRC in the proband only. All patients were studied with direct sequencing. Results Ten mutations were detected (10 of 25 [40%]); of nine different mutations, seven were novel. ThehMLH1 gene had a higher mutation detection rate thanhMSH2 (8 of 25 [32%] vs. 2 of 25 [8%]). Only 3 of these 10 families fulfilled the Amsterdam criteria. Two different polymorphisms were detected in thehMLH1 gene and four in thehMSH2 gene. Conclusions ThehMLH1 gene had a higher mutation detection rate thanhMSH2. The physician who deals with CRC must take into consideration the heredity issue with patients who present with an early age of onset or a familial history of CRC- or HNPCC-related cancers, including gastric cancer, even if they do not fulfill the former Amsterdam criteria.