2型猪链球菌新毒力因子PlcR的发现

<正>2型猪链球菌(SS2)是一种重要的人畜共患传染病病原体。SS2感染不仅可致猪急性败血症、脑膜炎、关节炎、心内膜炎及急性死亡,并且可通过伤口和呼吸道等传播途径,导致人的感染发病和死亡。1998年和2005年在我国江苏"苏中"地区和四川资阳等市县人群中曾先后两次暴发大规模SS2感染人的事件。人感染病例中出现了从未报道过的链球菌中毒性休克综合征(Streptococcal toxic shock syndrome,STSS),病死率高达80%以上,已成为重要的新发传染病病原体[1-4]。     

Human kallikrein 13 expression in salivary gland tumors

The human kallikrein 13 protein (hK13) is expressed in many normal tissues. Petraki et al have previously described presence of hK13 in salivary gland tissue, localized to duct epithelia and some acinar cells. The aim of this study was to determine whether hK13 is expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), in order to compare normal with tumor tissues. Pleomorphic adenomas (PA), adenoid cystic carcinomas (ACC), polymorphous low grade adenocarcinomas (PLGA), acinic cell carcinomas (ACI), mucoepidermoid carcinomas (MEC) and adenocarcinomas not otherwise specified (ANOS) of both minor and major salivary glands were examined. The results of this study indicate that most salivary gland tumors show high levels of expression of hK13. Overall, staining in PA was significantly less than that seen in normal salivary gland tissue. PLGA, ACC and ANOS each stained significantly more than normal salivary gland tissue while MEC and ACI did not. Ductal cells and cells lining duct-like structures showed a higher intensity of staining than non-ductal cells in most tumors. Tumors which exhibited only non-ductal cells also exhibited cytoplasmic staining. In conclusion, we demonstrate the high expression of hK13 in several common salivary gland tumors.     

The activity of selected glycosidases in salivary gland tumors

The monitoring of the patients after salivary gland tumors surgery is an important clinical issue. Still imperfect diagnostic procedures also remain a challenge for searching new sensitive and specific biomarkers of neoplastic processes in salivary glands. The aim of the presented study was an the assessment of the activity of HEX, with its isoforms HEX-A and HEX-B, GLU, GAL, MAN and FUC in salivary gland tumor tissues in comparison to a healthy salivary gland tissues taken during autopsy. A group of 42 patients with benign and malignant salivary gland tumors, aged 25-65 were examined. Fragments of salivary gland tumor tissue, fragments of healthy tissue removed during autopsy, blood serum and saliva were collected from patients with salivary gland tumors and healthy volunteers. In salivary gland tumor tissue the activity of HEX, HEX-A, HEX-B, GAL, FUC was considerably higher than in comparison to healthy salivary gland tissue and ascending trend of activity of GLU, MAN was also noticed. The activity of all lysosomal exoglycosidases in blood serum in patients with salivary gland tumors was considerably higher in comparison to healthy volunteers blood serum. The considerably higher activity of HEX, HEX-A, GLU, GAL, MAN, FUC and descending trend of activity of HEX-B were noticed in saliva of patients with salivary gland tumors in comparison to healthy volunteers. The assessment of HEX in blood serum and saliva of patients with salivary gland tumor can be possibly used in diagnostics and monitoring of salivary glands tumors.     

错配修复基因与涎腺肿瘤的关系

错配修复(mismatch repair,MMR)是DNA复制后的一种修复机制,对维持基因组稳定起重要作用.错配修复基因功能缺陷是继癌基因激活、抑癌基因失活之后又一肿瘤的发生、发展机制,错配修复基因的异常表达与全身多种肿瘤相关.涎腺肿瘤为口腔颌面部常见肿瘤之一,具有与其他系统肿瘤相似的组织学类型,多来源于肌上皮.近年来,有关涎腺肿瘤与错配修复基因的关系正逐步成为研究热点,本文就错配修复基因的组成、作用机制以及与涎腺肿瘤发生、发展的关系作一综述.     

Human kallikrein 6 expression in salivary gland tumors.

Human kallikrein 6 (hK6), also known as zyme/protease M/neurosin), is expressed in many normal glandular tissues. The aim of this study was to determine whether hK6 is expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), using an immunohistochemical method. Pleomorphic adenomas (PA), adenoid cystic carcinomas, polymorphous low-grade adenocarcinomas, acinic cell carcinomas, mucoepidermoid carcinomas, and adenocarcinomas not otherwise specified of both minor and major salivary glands were examined. Cells lining duct-like structures and non-duct-like cells were scored. Only in PA of minor salivary gland origin was overall staining higher in duct-like than in non-duct-like cells. In all other tumors exhibiting both types of cells, hK6 staining was similar in both duct-like and non-duct-like cells. Tumors that exhibited non-duct-like cells only also exhibited cytoplasmic staining. Results of this study show that salivary gland tumors express hK6, apparently downregulated in comparison with normal salivary gland tissue, and that this expression is not specific for any of the tumors studied.     

Dendritic cell tumor in a salivary gland lymph node: a rare differential diagnosis of salivary gland neoplasms

Background

We investigated the occurrence and clinical significance of mucin expression in ampullary adenocarcinoma.

Methods

We retrospectively analyzed clinical, pathological, and survival data from 74 ampullary adenocarcinoma patients who received radical operation from January 2004 to November 2006.

Results

The tumors were located in the lower end of the common bile duct (46%), papillary duodenum (42%), and ampullary duodenum (12%), and expressed MUC1 (72%), MUC2 (20%), MUC5AC (43%), and MUC6 (27%). Expression of MUC1 was associated with tumor differentiation (OR: 4.71, 95% CI: 1.26, 17.66, P = 0.021). Expression of MUC5AC was associated with age (OR: 1.07, 95% CI: 1.11, 1.14, P = 0.026) and less vessel invasion(OR: 0.14, 95% CI: 0.03, 0.72, P = 0.019). The survival rates were not significantly different when patients had or had no expression of MUC1, MUC2, MUC5AC, or MUC6 in tumor. Patients with tumors positive for MUC5AC in the papillary duodenum had worse survival than those with tumors negative for MUC5AC (P = 0.044).

Conclusions

Expression of MUC1 was high (72%) in ampullary adenocarcinoma, while expressions of MUC2, MUC5AC, and MUC6 were lower. Mucins are useful markers to diagnose and identify ampullary adenocarcinoma, particularly in determining the degree of malignancy of ampullary adenocarcinoma.     

Iron content of Streptococcus suis and evidence for a dpr homologue

The type strain of Streptococcus suis was investigated for features that might help the organism to tolerate the H2O2 that is produced during growth. Enzyme assays, using soluble extracts, revealed that the type strain, which lacks catalase, lacks NADH peroxidase in both the mid-exponential and stationary phases of the growth cycle. Although iron could not be detected colourimetrically in dense cell suspensions, determination of the cellular iron content following growth to early stationary phase in the presence of 55FeCl3 demonstrated that S. suis does contain iron and hence is incapable of iron exclusion. Gene amplification, using oligonucleotide primers based on dpr of Streptococcus mutans, followed by nucleotide sequencing, revealed in S. suis, the presence of a gene that encodes a Dpr homologue. It is concluded that in S. suis, tolerance of H2O2 is due to iron sequestration by Dpr and the consequent effect of this process on the extent of Fenton chemistry.     

Pre-absorbed immunoproteomics: a novel method for the detection of Streptococcus suis surface proteins

Streptococcus suis serotype 2 (SS2) is a zoonotic pathogen that can cause infections in pigs and humans. Bacterial surface proteins are often investigated as potential vaccine candidates and biomarkers of virulence. In this study, a novel method for identifying bacterial surface proteins is presented, which combines immunoproteomic and immunoserologic techniques. Critical to the success of this new method is an improved procedure for generating two-dimensional electrophoresis gel profiles of S. suis proteins. The S. suis surface proteins identified in this study include muramidase-released protein precursor (MRP) and an ABC transporter protein, while MRP is thought to be one of the main virulence factors in SS2 located on the bacterial surface. Herein, we demonstrate that the ABC transporter protein can bind to HEp-2 cells, which strongly suggests that this protein is located on the bacterial cell surface and may be involved in pathogenesis. An immunofluorescence assay confirmed that the ABC transporter is localized to the bacterial outer surface. This new method may prove to be a useful tool for identifying surface proteins, and aid in the development of new vaccine subunits and disease diagnostics.     

Rapid PCR test for Streptococcus suis serotype 7

Recent epidemiological studies on Streptococcus suis infections in pigs indicated that, besides serotypes 1, 2 and 9, serotype 7 is also frequently associated with diseased animals. For the latter serotype, however, no rapid and sensitive diagnostic methods are available. This hampers prevention and control programs. Here, we describe the development of a type-specific PCR test for the rapid and sensitive detection of S. suis serotype 7. The test is based on DNA sequences of capsular (cps) genes specific for serotype 7. These sequences were identified by cross-hybridization of several individual cps genes with the chromosomal DNAs of 35 different S. suis serotypes.     

Human salivary gland glycoconjugates: a lectin histochemical study

Summary The glycoconjugate content of normal salivary glands has been extensively investigated in humans by biochemical means and in non-human mammals by histochemical methods. However, there have been few histochemical studies of human tissues. This paper describes the findings obtained in parotid, submandibular and minor salivary glands by applying a panel of 13 biotinylated lectins, directed against a range ofn-linked, fucosylated and galactosylated sequences, using an avidin-peroxidase technique, with appropriate enzymatic and inhibitory sugar controls. The results were generally in accord with those observed in biochemical assays but the use of lectin histochemistry permitted the localizationin situ of small amounts of oligosaccharide and, therefore, allowed the recognition of subtle tissue differences. This study expands the current knowledge on the glycoconjugate composition of salivary glands and their lectin histochemistry and serves as a baseline for further studies, particularly in the field of neoplasia.     

Platelet-derived growth factor receptor regulates salivary gland morphogenesis via fibroblast growth factor expression

A coordinated reciprocal interaction between epithelium and mesenchyme is involved in salivary gland morphogenesis. The submandibular glands (SMGs) of Wnt1-Cre/R26R mice have been shown positive for mesenchyme, whereas the epithelium is beta-galactosidase-negative, indicating that most mesenchymal cells are derived from cranial neural crest cells. Platelet-derived growth factor (PDGF) receptor alpha is one of the markers of neural crest-derived cells. In this study, we analyzed the roles of PDGFs and their receptors in the morphogenesis of mouse SMGs. PDGF-A was shown to be expressed in SMG epithelium, whereas PDGF-B, PDGFRalpha, and PDGFRbeta were expressed in mesenchyme. Exogenous PDGF-AA and -BB in SMG organ cultures demonstrated increased levels of branching and epithelial proliferation, although their receptors were found to be expressed in mesenchyme. In contrast, short interfering RNA for Pdgfa and -b as well as neutralizing antibodies for PDGF-AB and -BB showed decreased branching. PDGF-AA induced the expression of the fibroblast growth factor genes Fgf3 and -7, and PDGF-BB induced the expression of Fgf1, -3, -7, and -10, whereas short interfering RNA for Pdgfa and Pdgfb inhibited the expression of Fgf3, -7, and -10, indicating that PDGFs regulate Fgf gene expression in SMG mesenchyme. The PDGF receptor inhibitor AG-17 inhibited PDGF-induced branching, whereas exogenous FGF7 and -10 fully recovered. Together, these results indicate that fibroblast growth factors function downstream of PDGF signaling, which regulates Fgf expression in neural crest-derived mesenchymal cells and SMG branching morphogenesis. Thus, PDGF signaling is a possible mechanism involved in the interaction between epithelial and neural crest-derived mesenchyme.     

Thermosensitive suicide vectors for gene replacement in Streptococcus suis

Three thermosensitive (Ts) suicide vectors, pSET4s, pSET5s, and pSET6s, have been constructed for gene replacement in Streptococcus suis. Each vector contains an antibiotic-resistance gene (spc or cat), a Ts replication origin of pWV01 lineage, multiple cloning sites, lacZ', and the ColE1 replication origin of pUC19. These vectors could be propagated at 37 degrees C in Escherichia coli, but their replication was blocked above 37 degrees C in S. suis. Moreover, the thermosensitivity of the replication origin was confirmed in S. equi ssp. equi, S. equi ssp. zooepidemicus, and S. dysgalactiae by using pSET4s. For inactivation of the sly gene, which encodes a thiol-activated hemolysin of S. suis, pSLYK, in which the sly gene was interrupted by the cat gene, was constructed using pSET4s and introduced into S. suis DAT2. After growth at the nonpermissive temperature under the antibiotic pressure, the chromosomal sly gene was replaced with the sly::cat gene of pSLYK by a double-crossover event at a rate of 2.6% among chloramphenicol-resistant cells. Moreover, complementation of the sly gene by use of the previously reported S. suis-E. coli shuttle vector pSET2 was demonstrated. These results indicate that the Ts suicide vectors described here will facilitate the genetic analysis of S. suis and other streptococci of veterinary importance by means of allelic exchange of the genes of interest via homologous recombination.     

Exploring the pan-surfome of Streptococcus suis: Looking for common protein antigens

Streptococcus suis is a swine and human pathogen for which no commercial vaccine is still available. Conserved and broadly distributed surface proteins have become the chosen targets for the development of efficacious vaccines that could overcome the problems of non-heterologous protection of bacterins or capsule polysaccharide-based vaccines. In this work, we have analyzed by proteomics a collection of 39 strains obtained from infected pigs. The isolates belonged to 19 of the most prevalent serotypes during the last years. We have applied the "shaving" approach to define the "pan-surfome" or the set of both common and unique surface proteins identified in such strains. This set was constituted by 113 proteins. We have categorized them for their potential for further vaccination studies, based on their distribution among strains and their a priori accessibility to antibodies. According to these criteria, the cell-wall protein SsnA appears to be the best candidate from this list, as it was that with the widest distribution among the analyzed pathogen types, it showed to be highly immunogenic and highly accessible to antibodies, as demonstrated by flow cytometry.     

Amoeba host model for evaluation of Streptococcus suis virulence

The Gram-positive bacterium Streptococcus suis is a major swine pathogen worldwide that causes meningitis, septicemia, and endocarditis. In this study, we demonstrate that the amoeba Dictyostelium discoideum can be a relevant alternative system to study the virulence of S. suis.     

Elevated plasma homocysteine in older shift-workers: a potential risk factor for cardiovascular morbidity

There is evidence supporting an association between shift work and cardiovascular morbidity, but the underlying mechanisms are unknown. The present paper investigated the levels of cardiovascular biochemical risk factors in shift-workers both with (n=26) and without (n=103) sleep complaints, and in day-workers (n=173) working in the same plant. Blood samples were taken in the morning after an overnight fast and analyzed for homocysteine, C-reactive protein, and lipid profile. Biochemical data were compared among groups after stratifying workers by age (i.e., <40 and > or = 40 yrs). Shift-workers who complained about sleep disturbances and who were > or = 40 years of age had significantly higher levels of homocysteine than did their younger counterparts - shift-workers who did not complain of sleep disturbances and day-workers. There were no other between-group differences in any of the biochemical variables. The results of this investigation demonstrate an association between sleep disturbances in older shift-workers and mild hyperhomocysteinemia. The elevated homocysteine levels may play a role in the increased rates of cardiovascular morbidity in shift-workers, and they may have practical implications regarding the nutrition of shift-workers.