植物U-box蛋白在植物先天免疫反应中的作用及其研究进展

为了分析植物U-box蛋白在植物先天免疫反应中的作用及其机制,总结了U-box的结构特点及其与RING-finger结构的异同;归纳了植物U-box蛋白的分类及分类特点;并综述了SPL11、PUB12/PUB13、PUB17等U-box蛋白在植物PTI信号传导途径中的调控作用与调控机制,以及ACRE276、PUB17、CMPG1、MAC3A/MAC3B等U-box蛋白在植物ETI信号传导途径中的调控作用与调控机制。得出植物U-box蛋白的结构特点、生化功能及其在植物先天免疫反应中的作用与分子机制,并认为对植物U-box蛋白的研究可为植物抗病分子育种提供基因资源与参考信息。

End-of-treatment virologic response does not predict relapse after lamivudine treatment for chronic hepatitis B

AIM: Attaining hepatitis B e antigen (HBeAg) seroconversion during lamivudine treatment is associated with fewer relapses in HBeAg-positive patients. In HBeAg-negative patients,predictors for post-treatment relapse remain largely unknown.We therefore studied whether end-of-treatment virologic response correlated with relapse after lamivudine treatment.METHODS: We prospectively analyzed 12 HBeAg-negative patients and 14 HBeAg-positive patients with chronic hepatitis B, who received at least 9 mo of lamivudine treatment and were followed up for 12 mo post-treatment. Relapse of hepatitis B activity was defined by an elevation of serum ALT level above twice the upper limit of normal as well as reappearance of serum HBV DNA by the branched DNA assay or HBeAg during the follow-up period. The serum viral loads during and at the end of treatment were further determined by a quantitative real-time polymerase chain reaction assay.RESULTS: Relapse occurred in 6 (50.0%) HBeAg-negative patients within 12 mo post-treatment. Two relapsers had end-of-treatment serum viral load < 1 000 copies/mL, the proportion was not significantly different from that in the 6 non-relapsers (33.3% vs 16.7%; P = 1.00). Hepatitis B virus (HBV) DNA levels did not correlate with post-treatment relapse in HBeAg-positive patients either. However, genotype C patients tended to have a lower relapse rate than genotype B patients (14.3% vs57.9%, P= 0.08).CONCLUSION: Our results suggest that end-of-treatment virologic response cannot predict post-treatment relapse in patients with HBeAg-negative or -positive chronic hepatitis B. The impact of HBV genotype on the response to lamivudine treatment awaits further studies.

Science Letters:A synthetic Toll-like receptor 2 ligand decreases allergic immune responses in a mouse rhinitis model sensitized to mite allergen

It has been proposed that activation of Toll-like receptors （TLRs） plays crucial roles in the polarization of adaptive immune responses. A synthetic Toll-like receptor 2 （TLR2） ligand, Pam3CSK4, has been reported to modulate the balance of Th1/Th2 responses. We evaluated the modulation effect of Pam3CSK4 on allergic immune response in a mouse rhinitis model sensitized to house dust mite allergen （HDM）. Mice were sensitized and challenged with Dermatophagoidesfarinae allergen （Der f）, and then the allergic mice were treated by Pam3CSK4. Nasal allergic symptoms and eosinophils were scored. Der f-specific cytokine responses were examined in the splenocytes and bronchoalveolar lavage fluid （BALF）. Serum level of total IgE was also detected. After establishing a mouse allergic rhinitis model with HDM, we have showed that Pam3CSK4 treatment not only ameliorated the nasal allergic symptoms remarkably but also decreased the eosinophils and total inflammation cells in BALF significantly. Analysis of cytokine profile found that IFN-7 released from either BALF or stimulated splenocytes increased markedly in Pam3CSK4-treated mice, while IL-13 decreased significantly. Moreover, serum level of total IgE was significantly lower in Pam3CSK4-treated mice than in the untreated. Thus, in an allergic rhinitis mouse model developed with HDM, Pam3CSK4 was shown to exhibit an antiallergic effect, indicating its potential application in allergic diseases.

Comparison between surgical outcomes of colorectal cancer in younger and elderly patients

AIM:To compare the outcome of surgical treatment of colorectal adenocarcinoma in elderly and younger patients.METHODS:The outcomes of 122 patients with colorectal adenocarcinoma who underwent surgical treatment between January 2004 and June 2009 were analyzed.The clinicopathological and blood biochemistry data of the younger group(<75 years) and the elderly group (≥75 years) were compared.RESULTS:There were no significant differences between the two groups in operation time,intraoperative blood loss,hospital stay,time to resumption of oral intake,or morbidity.The elderly group had a significantly higher rate of hypertension and cardiovascular disease.The perioperative serum total protein and albumin levels were significantly lower in the elderly than in the younger group.The serum carcinoembryonic antigen level was lower in the elderly than in the younger group,and there was a significant decreasing trend after the operation in the elderly group.CONCLUSION:The short-term outcomes of surgical treatment in elderly patients with colorectal adenocarcinoma were acceptable.Surgical treatment in elderly patients was considered a selectively effective approach.

HOUSE DUST MITE ALLERGEN (Derp1 AND Blot5) LEVELS IN ASTHMATICS' HOME IN HONGKONG

To measure Derp1 and Blot5 allergen levels in asthmatics’ homes in Hongkong. Methods Seventy houses were enrolled for a mite indoor environment study. Dust samples were obtained from two sites of each patients’ house: bed and floor. Derp1 and Blot5 levels were quantified by a two-site monoclonal antibody-based ELISA technique. Results The levels of Derp1 allergens found in bed (geometric mean (GM) 3.43 μg/g of dust; 95%CI, 1.89-4.96 μg/g) and on the floor (GM 1.12 μg/g of dust; 95%CI, 0.71-1.53 μg/g) indicated significant differences (P = 0.005). However, the levels of Blot5 allergens found in bed (GM 19.00 μg/g of dust; 95%CI, 0.89-38.90 μg/g) and on the floor (GM 6.14 μg/g of dust; 95%CI, 0.40-11.90 μg/g) showed no statistically significant difference. In addition, in regards to the exposure index for Derp1 and Blot5 allergens found in bed and on the floor, 17.6% in bed and 8.6% on the floor had levels of Blot5 ≥ 10 μg/g of dust, higher than those obtained for Derp1 (7.2% and 0% in bed and on the floor respectively, P < 0.05); higher percentages in bed and on the floor (25.0% and 35.7%) were observed for levels of Blot5 = 0 μg/g of dust as compared with Derp1 in bed and on the floor (4.3% and 14.5% respectively, P < 0.05). Conclusions Derp1 and Blot5 are the major allergens found in this regional study, Blot5 is a more potent allergen in Hongkong, probably reflecting the high level of exposure to Blomia tropicalis (Bt). Bt and Dermatophagoides pteronyssinus(Dp) allergens should be included for precise diagnosis and effective immuno-therapeutic treatment of mite allergy in Hong-kong.

DETECTION OF PATHOGENS CAUSING GENITAL ULCER DISEASE BY MULTIPLEX POLYMERASE CHAIN REACTION

Objective To establish a multiplex polymerase chain reaction （M-PCR） assay for simultaneous detection of pathogens causing genital ulcer disease （GUD）. Mothods Based on the gene-specific region of the following pathogens： Chlamydia trachomatis omp l/ompb, herpes simplex virus （HSV） DNA polymerase, Treponema pollidum tpp47, Haemophilus ducreyi 16s rRNA, four sets of primers were designed and an M-PCR assay was developed to detect four pathogens in one test. The assay was evaluated with diagnostic result of golden standard for each pathogen.Results Of the 51 clinical samples, M-PCR showed slightly higher positive rate （47.1%） of HSV than cell culture （23.6%）. Meanwhile, the positive rate of T. pallidum detected by M-PCR and dark-field microscopy was 19.6% （10/51） and 15.7% （8/51）, respectively. Only one sample was positive for H. ducreyi and no sample was positive for C. trachomatis detected by both M-PCR assay and culture. Conclusion This primary study indicated that M-PCR assay can simultaneously and rapidly detect the four etiologic pathogens causing GUD.

Enemy at the gates： dendritic cells and immunity to mucosal pathogens

Dendritic cells （DC） are diverse and specialized hematopoietic cells serving as an essential bridge between innate and adaptive immunity. DC exist in all lymphoid and nonlymphoid organs and are amongst the first responders to infection at epithelial surfaces including mucosal tissues. DC of the lung, gut, and vaginal mucosa display different phenotypes and functions reflecting each unique tissue and, in contrast to their counterparts in spleen and lymph nodes, are constantly exposed to both harmful and benign factors of their environments. Mucosal DC recognize and respond to pathogens through engagement of pattern recognition receptors, and activated DC migrate to draining lymph nodes to induce adaptive immune responses. The specialized function of DC aids in the induction of immunity and pathogen control at the mucosa. Such specialization includes the potent antiviral interferon response of plasma- cytoid DC to viral nucleic acids, the ability of mucosal DC to capture organisms in the gut lumen, the capacity of DC to cross-present antigen from other infected cells, and the ability of mucosal DC to initiate lgA class switching in B cells. DC plasticity is also critical in the immune response to mucosal pathogens, as DC can respond to the microen- vironment and sense pathogen-induced stress in neighboring epithelial cells. Finally, DC interact with each other through crosstalk to promote antigen presentation and T-cell immunity. Together, these processes condition mucosal DC for the induction of a tailored immune response to pathogens.

Relationship between the downregulation of HLA class Ⅰ antigen and clinicopathological significance in gastric cancer

AIM:To discuss the expression of human leukocyte antigen (HLA) class Ⅰ antigens in gastric cancer and correlate these with pathologic type and TNM stage. METHODS: The expression of HLA class Ⅰ antigen was detected by immunohistochemistry in 185 specimens of gastric cancer, 20 gastric cancer specimens with lymphatic metastasis and 22 controls of normal gastric mucosa using four monoclonal antibodies. RESULTS: The expression of HLA class Ⅰ antigen (B/C locus) was significantly downregulated in gastric cancer and in lymphatic metastasis than that in normal gastric mucosa (x2=7.712, P<0.05). The expression of other HLA class Ⅰ antigens was also downregulated, but the change was slight. There was no relationship between the downregulation of HLA class Ⅰ antigen and that of β2m and LMP2. The expression of HLA class Ⅰ (B/C locus) was statistically correlated with pathologic stage in gastric adenocarcinoma (x2=4.164,P<0.05). CONCLUSION: The expression of HLA class Ⅰ antigen (B/C locus) was obviously downregulated in gastric cancer and in lymphatic metastasis. This abnormal expression would provide the tumor cells with a way to avoid immunological recognition.

Apparent dose dependent antibody response in chickens immunized with orthopox virus antigens

Dose-dependent IgY antibody response to different amounts oforthopox virus （OPV） antigen has been studied in immunized chickens for two different OPV strains （vaccinia virus, 7.0× 10^6 PFU and cowpox virus, 9.2× 10^7PFU）. The antibody responses to different immunizations were tested and compared by indirect immunofluorescence antibody test. Our results, together with the literature, show that the antigen dose used for immunization plays an important role for the production of specific Abs. An increase in antigen concentration may achieve higher Ab titers but, dependent on the immunogenicity of OPV antigen, it can also lead to an immune depression. However, in this study we found that OPV played a positive correlation between antigen concentration and Ab-titer.

稻瘟菌无毒基因AvrPii编码蛋白分子特性及转基因水稻的构建

为了解稻瘟菌无毒基因AvrPii在水稻病原菌相关分子模式诱导的免疫反应(PTI)抗病分子信号调控中的功能,对AvrPii基因编码蛋白的分子结构特性进行分析,构建了AvrPii基因的植物表达载体幵进行遗传转化。结果表明:AvrPii蛋白由70个氨基酸组成,相对分子质量约为7 500,等电点为6.0,总平均亲水性值为–0.159;AvrPii蛋白包含1个信号肽、1个跨膜结构域和2个基序为LxAR和CxxCxxxxxxxxxxxH的保守结构域;利用农杆菌侵染转化法,获得AvrPii基因全长序列和不含信号肽AvrPiinsp的转基因株系13个,PCR扩增和实时荧光定量PCR鉴定结果表明,AvrPii和AvrPiinsp基因已成功转入受体品种日本晴幵得到稳定表达。

Gene-Ontology Analysis on the Differentially Expressed Genes in Maize （Zea mays L.） Ear Rot

To better know FM （Fusarium moniliforme） induced genes in maize ear rot, GO （gene ontology） method was performed to analyze detail physiological functions in the defensive response after pathogen infection. This gene annotation system was widely used to investigate large numbers of genes involving in real active role or regulator in cell response. First of all, differentially expressed genes were isolated by using genechip platform at 96 h post-inoculation with FM in maize inbred Bt-1. In total, 482 differentially expressed unique genes were screened out in inbred Bt-1 when compared to mock-inoculated bract tissues. Then, each gene was annotated to define functional class by GO method. Finally, these large FM-responsive genes with significant differentially change were sorted into cellular component, molecular function and biological process with complicated network by molecular annotation system. The demonstrated information in the GO analysis could provide another view for understanding the molecular mechanism and indicate a deeply complicated network with gene function underlying disease development in the host tissue. The findings in this study provide important bases to probe the molecular processes, the alteration of metabolism and the immune mechanism upon the FM infection in maize.

Quantitation of Genital Herpes Virus DNA by Polymerase Chain Reaction and ELISA

Objective: To detect and quantitate genital herpes simplexvirus (HSV) DNA in specimens from 100 patients clinicallydiagnosed with genital herpes. Methods: Polymerase Chain Reaction (PCR) andenzyme-linked immunosorbent assay (ELISA) were used witha standard curve of DNA copies of HSV as quantitativecontrast. Results: Ninety-three cases were confirmed HSV positiveand 7 cases were found to be negative. There were 58 cases ofHSV-2 (62.4%) and 35 cases of HSV-1(37.6%) among the 93positive cases. The number of DNA plasmids ranged from 115to 1.1×10~5 per 250μL among the 93 positive samples (mean=7.1×10~4/250μL). The number of HSV DNA plasmids rangedfrom 136 to 1.1×10~5 copies per 250μL(mean=7.6×10~4) amongthose with HSV-2, and 115 to 9.4×10~4 per 250μL(mean=6.3×10~4) among those with HSV-1. Meanwhile 10μL ofextracted and dissolved DNA randomly taken from 8 each ofHSV-2 and HSV-1 samples were tested. The number of HSV-2DNA plasmids ranged from 35 copies to 2.7×10~4 (Mean=1.8×10~4) and the number of HSV-1 DNA ranged from 29 to2.5×10~4 (Mean=1.6×10~4). In the 7 negative cases, the quantityof HSV plasmids was zero. Conclusion: The sensitivity of ELISA quantitation (93%) isequal to that of Southern blot. The sensitivity of PCR fordiagnosis is 91%, and 88% for PCR typing.

Hepatitis B virus S gene enhances immune responses of a multiple-epitope DNA construct of hepatitis C virus in mice

The purpose of this study was to construct an eukaryotic DNA vector encoding a multiple-epitope antigen (MFC) of hepatitis C virus (HCV) and a hepatitis B surface antigen (HBsAg) , and explore the effect of HBsAg gene on the immunity of HCV multiple-epitope DNA construct in vitro and in vivo in mice. An HCV DNA vector (pVAX1-HBs-MFC) was constructed by fusing HBsAg gene to the N-terminal of an HCV multiple-epitope antigen gene. The pVAX1-HBs-MFC was transfected into HEK 293T cells and its expression was measured by ELISA and Western blotting. BALB/c mice were intramuscularly immunized with the pVAX1-HBs-MFC, and an ELISA approach was applied to determine the specific antibody titers and subtypes in the mouse serum. The cross-reactivity of the antibodies was also checked with two synthesized HCV hypervariable region 1 (HVR1) peptides. The IFN-γ production and cell proliferation of the mouse spleen cells were evaluated by ELISA and MTS (3-[4, 5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl] -2H-tetrazolium, inner salt) assays, respectively. The expression of pVAX1-HBs-MFC was detectable in the transfected HEK 293T cells. The serum antibody response was effectively elicited in BALB/c mice injected with pVAX1-HBs-MFC. The highest titer of antibody against HCV (MFC) was 1∶1280, and the ratio of IgG2a/IgG1 was 1.50±0.12 at the fifth week after first immunization. Moreover, the collected mouse serum antibody had the ability to cross-react with the two synthesized HCV HVR1 peptides. The stimulation index of the mouse splenocytes to MFC was 1.79 ±0.07, and the IFN-γ level was 287±6?pg/ml at week 21 after first immunization. The highest titer of the antibody in control BALB/c mice immunized with pVAX1-MFC was 1∶320, and the ratio of IgG2a/IgG1 was 1.33±0.11 at week 5 post-immunization. Furthermore, the stimulation index of the mouse splenocytes cells to MFC was 1.52±0.06, and the IFN-γ level was 225±9.3?pg/ml at week 21 post-immunization. The HBsAg gene can enhance the effects of an HCV multiple-epitope DNA construct on its humoral and cellular immune responses. This HBsAg enhanced HCV multiple-epitope DNA vector may be of potential use in the development of HCV vaccines.

异源器官移植研究进展

异源器官移植是解决人类器官资源短缺的一条可行途径,尽管近来迫切需要这种移植方式来满足对器官的需求、延续器官功能,但还存在很多问题阻碍了它的临床应用,其中包括人体对外来器官的免疫排斥、病原微生物的感染以及一系列的伦理、道德和社会问题。从异源器官移植的发展历史着手,根据其面临的主要难题,结合当今的发展进展,对其应对策略进行了探讨,并展望了异源器官移植的发展道路。

Identification of 11 STD Pathogens in Semen Using Polymerase Chain Reaction （PCR） and ＂Flow-through＂ Hybridization Technology

The transmission of sexually transmitted infection （STI） pathogens from an infected donor to the recipient of a semen donation in assisted conception may result not only in acute infection but also in long-term reproductive complications or adverse outcomes of pregnancy including infection of the offspring. Semen samples were obtained by masturbation into sterile containers. Samples were subjected to semen analysis within one hour of collection and processed for freezing within two hours of collection. The sperm motility was determined. After DNA extraction the PCR was performed and amplicons are subsequently hybridized to pathogen-specific capturing probes via ＂Flow-through＂ hybridization. During our study we came across with the STI pathogens present in semen and main cause of infertility was note. It was also observed that route for the transfer for these STI pathogens were the men working in other cities and visited commercial sex workers and their complained for infertility. We have reported our data that after the normal sperm count in semen samples of men with infertility or subfertility they were infected with Chlamtdia trachomatis, Neisseria gonorrhoeae, and Mycoplasma hominis. In our study all the 11 pathogens were detected which cause serious reproductive complications and infection in their offspring.

Toll-like receptors,a double-edged sword in immunity to malaria

Toll-like receptors(TLRs) are a central component of innate immune system and play a major role as the initiator of the innate immune responses to defend against bacteria,viruses,parasite and other pathogens.During malaria infection,TLRs signaling pathways are initialed with the recognition of Plasmodium glycosylphosphatidylinositols(GPI) and hemozoin as pathogen-associated molecular patterns(PAMPs).And then,activation of TLRs signaling induces specific biological responses against malaria parasites invasion.However,TLRs are also involved in malaria pathogenesis and enhancement of immune tolerance and evasion for malaria infection.Moreover,malaria parasites regulate selectively TLRs expression on immune cells.Thus,these evidences indicated that TLRs have contrary roles on malaria infection.Understanding the complicated roles of TLRs on malaria infection will contribute us to design more effective anti-malaria drugs or vaccines.

New perspectives in occult hepatitis C virus infection

Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV. This occult infection has been reported also in healthy populations without evidence of liver disease. Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma. Thus, anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylated-interferon plus ribavirin. The persistence of very low levels of HCV RNA in serum and in PBMCs, along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C, indicate that occult HCV is a persistent infection that is not spontaneously eradicated. This is an updated report on diagnosis, epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

Rapid Identification of Pathogenic Bacteria by means of TwoConservative Gene Loci′ Specific PCR-CE-RFLP

To establish a rapid identification method for common pathogenic bacteria on the basis of molecular biology and to construct a preliminary Polymerase Chain Reaction-Capillary Electrophoresis - Restriction Fragment Length Polymorphism (PCR-CE-RFLP) database of bacteria isolated from clinical specimens frequently, 183 strains collected from clinical samples belonging to 12 genera and 19 species whose biochemical characterizations corresponded to the typical ones were examined. The genomic DNAs were amplified by two pairs of fluorescence labeled primers aiming at 16S rRNA gene and 16S-23S rRNA spacer region gene respectively at the same time. PCR products were then digested by restriction endonuclease HaeⅢ incompletely before taking capillary electrophoresis. The results with the PCR-CE-RFLP patterns of 16S rRNA genes were just alike within some genera, but when it comes to 16S-23S rRNA spacer region genes, each bacterium showed a unique pattern, which can be distinguished from each other easily. It seems that PCR-CE-RFLP patterns of 16S rRNA gene could only be used to classify the bacteria into family level, whereas the data of 16S-23S rRNA spacer region gene could be utilized to identify the whole microorganisms as precisely as the species level. In spite of the data of the spacer region gene alone can be sufficiently to verify the whole bacteria, we insist that the 16S rRNA gene could be of some assistant in case that there should be lots of families of bacteria, in which some similar ones, with the same RFLP data of 16S-23S rRNA spacer region gene, may coexist. This study proves that the utility of PCR-CE-RFLP is a convenient, rapid method to identify pathogenic bacteria, and is also a quick diagnosis measure for application to clinical use.

Detection of Delayed Hypersensitivity to Fonsecaea pedrosoi Metabolic Antigen （Chromomycin）in Healthy People in an Endemic Area

The CBM （chromoblastomycosis） is a disease caused by dematiaceous fungi, which has the species Fonsecaea pedrosoi as main agent. This fungus is found in warm and moist climates, characteristically found in the amazonic lands of the region, where its environmental isolation was once described. This research aimed to identify the healthy population exposed to agent F. pedrosoi in four villages located in the Legal Amazon. In order to clarify the risk factors for allergic immune exposure, a survey was conducted by the technique of delayed skin reaction （IDR） with the metabolic antigen （chromomycin） in 449 healthy individuals. The results showed that 14.9% （67 subjects） were IDR positive, with induration 〉 5 mm. Multivariate analysis with logistic regression for risk factors： living in the village of Z6 Pedro （municipality of Bacabeira in the state of Maranhao, Brazil）,

Alteration in Biochemical Response in Sesamum indicum upon Different Plant-Pathogen Interactions

Sesamum, an important oil yielding crop suffers a huge loss in its yield due to attack of large number of fungal pathogens. In semi-arid regions Sesamum is mainly affected by two major plant-pathogenic fungus viz. Macrophomina phaseolina and Fusarium oxysporum. The aim of the study was to analyze the metabolic alterations in Sesamum after infection with both pathogens. This accomplished by individually by （the word estimating is not quantitative） the levels of total phenolic compounds and the activities of phenylalanine ammonia lyase （PAL） of one week old plants. The PAL showed high activity in infected plants, revealing the active phase in the synthesis of secondary metabolites in the Sesamum plant after infection. As a consequence, in infected plants the contents of polyphenols along with salicylic acid （SA） considerably exceeded when compared to control plants. This in vivo study of M. phaseolina and F. oxysporum infection reveals the differences of resistance levels in sesame against these two pathogens. These results provide important information regarding the plant-pathogen interactions and also forfor Sesamum improvement programs seeking the adaptation to diverse range of fungal attack along with adverse environmental factors.