Biomedical subjects

Jie Dong

Publications and source records attributed to Jie Dong.

At least 37 records · Page 2Linked to original sources

PubMed2006

[Laboratory diagnoses of the first confirmed human case of avian influenza A (H5N1) in the mainland of China].

BACKGROUND: To determine the etiologic agent of an atypical pneumonia human case admitted to Xiangtan City hospital, Hunan Province in Oct. 2005. METHODS: The patient's respiratory tract samples and serum were collected. Throat swabs were tested by microneutralization and hemagglutination-inhibition assays. RESULTS: The results of nucleic acid detection of all respiratory samples were negative and virus isolation was also negative. The H5-specific antibodies of convalescence showed a 4-fold greater rise than acute phase. CONCLUSION: The atypical pneumonias case was confirmed as the first human case of avian influenza A (H5N1) infection in the mainland of China.

Animals↗

PubMed2006

[Development of methods for detection of H5N1 from human clinical specimens].

BACKGROUND: To establish a method for H5N1 RNA detection and laboratory diagnosis of suspected human avian influenza (H5N1) virus infected cases. METHODS: The typing and sub-typing primers were designed according to M and H5 and N1 gene respectively, and the RT-PCR and real-time PCR were developed using these primers. RESULTS: The RT-PCR and real-time PCR could be used for H5N1 detection specifically, and there was no cross reaction with other influenza subtypes such as H1 and H3. The sensitivity for RT-PCR and real-time PCR was 1 TCID50 and 0.01 TCID50 respectively. Thirteen laboratory confirmed human H5N1 cases were detected from 42 suspected cases by using these methods. CONCLUSION: The established RT-PCR and real-time PCR methods can be used for laboratory detection of suspected human H5N1 cases.

Animals↗

PubMed2006

Rapid identification of small interfering RNA that can effectively inhibit the replication of multiple influenza B virus strains.

Influenza B virus is a cause of substantial morbidity and mortality in humans and current vaccination strategies and antiviral drugs only provide limited protection. Here, we report the evaluation of small interfering RNA (siRNA) for repression of viral replication in cultured cells as well as in chicken embryos. Several siRNAs targeting conserved regions of the virus (in chemically synthesized or plasmid-encoded forms) were found to effectively block the replication of the influenza B virus. The siRNAs were found to offer broad protection over several strains of influenza B virus (B/Beijing/76/98, B/Beijing/37/99 and B/Jiangsu/10/03) that differ substantially in their genetic content. The antiviral effects of 500 ng siRNA-encoding plasmids or 60 nmoles synthetic siRNA were found to be comparable to that of 3.6 microg ribavirin. These results indicated that RNA interference warrants further study for management of influenza B virus infections.

Animals↗

PubMed2006

[The first confirmed human case of avian influenza A (H5N1) in mainland, China].

OBJECTIVE: To ascertain the causation of a family cluster involving two undefined pneumonia cases, a 12-year-old girl and her brother, reported October, 2005 in Xiangtan county, Hunan province. METHODS: Information on epidemiology and clinical manifestation of the cases was collected from interviewing the keyman and referring to related medical records. The environment exposure of the cases to their households and the timeline of the illness were reproduced, using this information. Medical check-up was undergone among the close contacts of the cases and on sick/dead poultry. Throat swab of the cases were collected and tested by both RT-PCR and real-time PCR to detect viral nucleic acids of A/H5N1, and were then inoculated into special pathogen free (SPF) embryonated hens' eggs. Serum of the cases including acute and convalescent phases were also collected and tested by microneutralization and haemagglutination-inhibition (HI) assays to detect H5-specific antibodies. RESULTS: Both the girl and her brother developed fever 2 and 4 days after sudden deaths of chickens being raised in the same house. Both of them had developed pneumonia and the girl died from acute respiratory distress syndrome (ARDS) complicated with multi-organ failure. The boy survived and subsequently discharged from hospital. An eighth-day serum from the girl tested H5 antibody negative, while 4-fold and greater increased in antibody titers were detected in serum from the boy using microneutralization and HI assays in sequential acute and convalescent sera. Of 192 cases, only one doctor who cared for the girl during hospitalization had upper respiratory symptoms but tested negative for H5N1 by microneutralization assay. CONCLUSION: The boy was the first confirmed human case of avian influenza A (H5N1) in the mainland of China and his sister was diagnosed clinically. The most probable explanation of these two cases was that the transmission of H5N1 virus from infected poultry within the same household environment. No evidence of human-to-human transmission was noted in the family cluster.

Animals↗

PubMed2006

[Study on a fatal pregnant woman died from by avian influenza (H5N1)].

OBJECTIVE: To ascertain the causation of a pregnant woman with undefined pneumonia reported from the People's Hospital of Tongling city in Anhui province on November 2005. METHODS: Epidemiological and clinical information of the case was collected from the keypersons close to the case and referring to the medical record. A medical observation was carried out on the close contacts of the case and sick or dead poultry. Tracheal aspirates being collected were tested by both RT-PCR and real-time PCR to detect viral nucleic acids of A/H5N1, and were inoculated into special pathogen free (SPF) embryonated hens' eggs. RESULTS: The pregnant woman was found to have been contacted with the sick/dead poultry directly on the 4th day before onset of illness. All the 122 close contacts were healthy after a 10-day medical observation. The major clinical features of the case were viral pneumonia with rapidly developed leukopenia and lymphopenia. The progress to acute respiratory distress syndrome and multiple organ dysfunction syndromes was found at clinical presentation. HA and NA gene of A/H5N1 virus were positive. The 8 gene fragments of A/Anhui/1/2005 (H5N1) isolated from the tracheal aspirates had not carried genes from a human virus through reassortment, and the receptor-binding site of the hemagglutinin was polybasic cleavage site. CONCLUSION: This was the first documented case of H5N1 infection in pregnant woman. The immunotolerant state of pregnancy might have predisposed to the fatal outcome of the patient.

Adult↗

PubMed2005

Genome dynamics and diversity of Shigella species, the etiologic agents of bacillary dysentery.

The Shigella bacteria cause bacillary dysentery, which remains a significant threat to public health. The genus status and species classification appear no longer valid, as compelling evidence indicates that Shigella, as well as enteroinvasive Escherichia coli, are derived from multiple origins of E.coli and form a single pathovar. Nevertheless, Shigella dysenteriae serotype 1 causes deadly epidemics but Shigella boydii is restricted to the Indian subcontinent, while Shigella flexneri and Shigella sonnei are prevalent in developing and developed countries respectively. To begin to explain these distinctive epidemiological and pathological features at the genome level, we have carried out comparative genomics on four representative strains. Each of the Shigella genomes includes a virulence plasmid that encodes conserved primary virulence determinants. The Shigella chromosomes share most of their genes with that of E.coli K12 strain MG1655, but each has over 200 pseudogenes, 300 approximately 700 copies of insertion sequence (IS) elements, and numerous deletions, insertions, translocations and inversions. There is extensive diversity of putative virulence genes, mostly acquired via bacteriophage-mediated lateral gene transfer. Hence, via convergent evolution involving gain and loss of functions, through bacteriophage-mediated gene acquisition, IS-mediated DNA rearrangements and formation of pseudogenes, the Shigella spp. became highly specific human pathogens with variable epidemiological and pathological features.

DNA Transposable Elements↗

PubMed2005

A novel peptide isolated from phage library to substitute a complex system for a vaccine against staphylococci infection.

Staphylococcus aureus is a major human pathogen and many of the strains are resistant to conventional antibacterial treatment. The bacteria cause disease largely due to the production of multiple toxins, whose synthesis is controlled by an RNA molecule termed RNAIII. The production of RNAIII is induced by quorum sensing systems, one of them containing the protein RNAIII activating protein (RAP). Here we show that we partially purified supernatant of S. aureus, used this fraction to vaccinate mice, and selected antibody-binding peptides by phage display. Mice were vaccinated with the various peptides and challenged with S. aureus. One of the binding peptide termed R13 induced a protective immune response. Western blot analysis showed that the anti-R13 antibodies specifically bind to native or recombinant RAP. Mice vaccinated with R13 were protected and protection was sustained for the duration of the 6-month study period. Our results show that R13 could be used as a long-term effective protective-peptide-vaccine to prevent S. aureus infections and once again show that targeting the RAP quorum sensing system is an effective approach to preventing staphylococcal infections. In addition our studies show that selection of specific protective peptides by phage display using sera induced by complex antigens is a rapid and effective way to identify the protective antigen and select for a peptide vaccine.

Animals↗

PubMed2005

A novel peptide screened by phage display can mimic TRAP antigen epitope against Staphylococcus aureus infections.

Staphylococcus aureus is a major human pathogen. Pathogenic effects are largely due to production of bacterial toxins, whose synthesis is controlled by an mRNA molecule termed RNAIII. The S. aureus protein called RAP (RNAIII-activating protein) is secreted and activates RNAIII production by inducing the phosphorylation of its target protein TRAP (target of RAP). Antibodies to TRAP have been shown to suppress exotoxin production by S. aureus in vitro, suggesting that TRAP may be a useful vaccine target site. Here we showed that a peptide TA21 was identified by screening a phage display library using anti-TRAP antibodies. Mice vaccinated with Escherichia coli engineered to express TA21 on their surface (FTA21) were protected from S. aureus infections, using sepsis and cellulitis mice models. By sequence analysis, it was found that the TA21 is highly homologous to the C-terminal sequence of TRAP which is conserved among S. aureus and Staphylococcus epidermidis, suggesting that peptide TA21 may be a useful broad vaccine to protect from infection caused by various staphylococcal strains.

Animals↗

PubMed2005

The complete sequence and analysis of the large virulence plasmid pSS of Shigella sonnei.

The complete sequence of pSS, which is the large virulence plasmid of Shigella sonnei, was determined. The 214-kb plasmid is composed of segments of virulence-associated genes, the O-antigen gene clusters, a range of replication and maintenance genes, and large numbers of insertion sequence (IS) elements. Two hundred and forty-one open reading frames (ORFs) were identified, of which 117 are highly homologous to IS elements or transposases, 57 are homologous to known pathogenesis-associated proteins, and 30 are related to replication, plasmid maintenance, or other metabolic functions. Thirty-seven ORFs have no similarity to proteins with a known function, including two with no significant similarity to any hypothetical proteins. Interestingly, 10 ORFs encoding O-antigen gene clusters were identified on the plasmid and this is markedly different from most other Shigella spp. virulent plasmids. A novel toxin-antitoxin system, a series of stbDE homologs, was found on the plasmid immediately downstream of the replication region; the sole segregation stability system may be responsible for the instability of pSS. The pSS plasmid is a mixture of genes with different origins and functions. The sequence suggests a remarkable history of IS-mediated recombination and acquisition of DNA across a range of bacterial species.

Bacterial Proteins↗

PubMed2005

Interleukin-6 and mevastatin regulate plasminogen activator inhibitor-1 through CCAAT/enhancer-binding protein-delta.

OBJECTIVE: We sought to determine the etiologic mechanism of proinflammatory cytokine, interleukin-6 (IL-6), and statin as regulators of synthesis of plasminogen activator inhibitor-1 (PAI-1), the physiological fibrinolysis inhibitor and an acute-phase reactant. METHODS AND RESULTS: Transient transfection and luciferase assay in HepG2 human hepatoma-derived cells demonstrated that IL-6 increased PAI-1 promoter activity and mevastatin decreased IL-6-inducible response. Systematic deletion assay of the promoter demonstrated that the region (-239 to -210 bp) containing a putative CCAAT/enhancer-binding protein (C/EBP) binding site was necessary. Point mutation in this site abolished the IL-6-inducible response. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that C/EBPalpha, C/EBPbeta, and C/EBPdelta were involved in protein-DNA complex formation in intact cells. Deoxyribonuclease (DNase) I footprinting analysis revealed that 5' flanking region (-232 to -210 bp) is acute-phase response protein-binding site. C/EBPdelta binding activity was increased by IL-6 and attenuated by mevastatin. Mevastatin attenuated IL-6-mediated increase of C/EBPdelta protein in the nuclear extracts. IL-6 also increased PAI-1 and C/EBPdelta mRNA in mouse primary hepatocytes. CONCLUSIONS: IL-6 increases hepatic PAI-1 expression mediated by the -232- to -210-bp region of the promoter containing a C/EBPdelta binding site. Vascular protection by statins may be partly mediated through regulation of CEBPdelta and consequent modulation of PAI-1 expression.

Animals↗

PubMed2005

Identification and characterization of a family of Caenorhabditis elegans genes that is homologous to the cadmium-responsive gene cdr-1.

Six Caenorhabditis elegans genes that are homologous to the novel, cadmium-responsive gene cdr-1 have been identified and characterized. Nucleotide and amino acid sequence comparisons among the CDR family, which includes cdr-1, cdr-2, cdr-3, cdr-4, cdr-5, cdr-6, and cdr-7, reveals a high degree of identity among the seven members in this family. There are high levels of amino acid and nucleotide sequence similarity in the lengths of the open reading frames, predicted sizes, and protein characteristics. The seven proteins are predicted to be extremely hydrophobic, and are classified as integral membrane proteins. Structural analysis of the predicted proteins suggests that they may have similar biological functions. In response to cadmium exposure, cdr-1, cdr-2, cdr-3, and cdr-4 transcription significantly increases. In contrast, the levels of cdr-5, cdr-6, and cdr-7 transcription are not significantly affected or inhibited by cadmium exposure. Further, in non-exposed C. elegans, cdr-2, cdr-4, cdr-6, and cdr-7 are constitutively expressed. When CDR-1 expression was inhibited using RNAi, numerous fluid droplets were observed throughout the nematode body cavity. This phenotype became more pronounced in the presence of hypotonic stress. This suggests that CDR-1 may function in osmoregulation to maintain salt balance in C. elegans.

Amino Acid Sequence↗

PubMed2005

Construction, detection and microarray analysis on the Shigella flexneri 2a sitC mutant.

In order to overcome the defects of difficult gene operations in low-copy suicide plasmid pCVD442, Gateway technology was applied in the construction process of recombinant plasmid for gene knockout in this study. With this improved knockout system, we inactivated sitC gene, which is associated with iron transport in Shigella flexneri 2a strain 301, to yield the mutant, MTS. The functional detection of the mutant was performed at the level of culture medium, cell and animal experiment, respectively. The gene expression profiles were compared with DNA microarray between the mutant and the wild type under iron-restricted conditions. The results showed that MTS grew obviously less well than the wild-type strains in L broth containing 150 micromol/L iron chelator DIP (2,2'-dipyridyl). Addition of iron or manganese to the cultures stimulated the growth of MTS to wild-type levels in rich culture medium. In either the experiment on the ability of intracellular multiplication and cell-to-cell spread in HeLa and U937 cell lines, or the experiment on keratoconjunctivitis in guinea pigs, MTS showed no obvious changes in virulence compared with the parental strain Sf301. When 65 micromol/L DIP was added to the cultured HeLa cells, the ability of intracellular multiplication of MTS reduced about 51.6% as compared with that of Sf301. The analysis of expression profiles under iron-limited condition showed that MTS was more sensitive for the change of iron deficiency than Sf301. There are 106 more up-regulated genes in MTS than in wild-type strains, which are involved in membrane transportation, amino acid metabolism and uncategorized function genes, while down-regulated genes are mainly involved in energy and carbohydrate metabolism. Under low iron conditions, the expression levels of known iron-transport associated genes generally increased. Additionally, the number of these genes and their increase amplitude in MTS are more than those in Sf301. Together, these results confirmed that Sit iron-transport system is important for the growth of Shigella.

ATP-Binding Cassette Transporters↗

PubMed2005

Genetic characteristics of human enterovirus 71 and coxsackievirus A16 circulating from 1999 to 2004 in Shenzhen, People's Republic of China.

The genetic and phylogenetic characteristics of human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) sampled from children with hand, foot, and mouth disease in Shenzhen, People's Republic of China, over a 6-year period (1999 to 2004) were examined with reverse transcription-PCR and DNA sequencing. Out of 147 stool specimens, 60 showed positive signals when screened with EV71- and CA16-specific primers. EV71 was identified in 19 specimens, and CA16 was identified in 41 specimens; coinfection by EV71 and CA16 was not observed. Phylogenetic analysis of all EV71 strains isolated from the mainland Chinese samples established C4 as the predominant genotype. Only one other known strain (3254-TAI-98; AF286531), isolated in Taiwan in 1998, was identified as belonging to genotype C4. Phylogenetic analysis of CA16 strains allowed us to identify three new genetic lineages (A, B, and C), with lineage C recently predominating in Asian countries, such as the People's Republic of China, Malaysia, and Japan. These new observations indicate that CA16 circulating in the People's Republic of China is genetically diverse, and additional surveillance is warranted.

Enterovirus↗

PubMed2005

Comparative genomics and phylogenetic analysis of S. dysenteriae subgroup.

Genomic compositions of representatives of thirteen S. dysenteriae serotypes were investigated by performing comparative genomic hybridization (CGH) with microarray containing the whole genomic ORFs (open reading frames, ORFs) of E. coli K12 strain MG1655 and specific ORFs of S. dysenteriae A1 strain Sd51197. The CGH results indicated the genomes of the serotypes contain 2654 conserved ORFs originating from E. coli. However, 219 intrinsic genes of E. coli including those prophage genes, molecular chaperones, synthesis of specific O antigen and so on were absent. Moreover, some specific genes such as type II secretion system associated components, iron transport related genes and some others as well were acquired through horizontal transfer. According to phylogenic trees based on genetic composition, it was demonstrated that A1, A2, A8, A10 were distinct from the other S. dysenteriae serotypes. Our results in this report may provide new insights into the physiological process, pathogenicity and evolution of S. dysenteriae.

Genes, Bacterial↗

PubMed2005

Structural and functional analysis of denitrification genes in Pseudomonas stutzeri A1501.

Four gene clusters associated with denitrification were identified in the genome of A1501 strain, nar, nir, nor and nos, including 40 genes totally, which encode proteins for substance transportation, gene regulation and reductases. The three gene clusters, nir, nor and nos are adjacent on chromosome and are far from nar gene cluster. Compared with other denitrifying bacteria, the 40 denitrification genes in A1501 strain compose a complete denitrification catalysis system. In A1501 strain, this system has the following characteristics: (i) only one copy of narK gene is found in nar gene cluster; (ii) a narM gene is present between narK and narG; (iii) two genes, dnarE and orfl are identified at downstream of narX and narL genes, of which dnrE perhaps is a transcriptional factor belonging to FNR family; (iv) there are 16 nir genes in A1501, the most in the known denitrifying bacteria; (v) it is for the first time that norR gene has been found in A1501 and also in Pseudomonas; (vi) nos gene cluster is relatively conservative, with a completely identical composition and arrangement of genome to the reference bacteria strain.

Escherichia coli↗

PubMed2004

A subtractive fluorescence-activated cell-sorting strategy to identify mimotopes of HBV-preS protein from bacterially displayed peptide library.

A novel subtractive fluorescence-activated cell-sorting (FACS) strategy using a model system is described here to identify disease-specific (DS) epitopes from a bacterially displayed random peptide library. In this process, preimmune serum was used as "Driver " to block any common binding sites on the bacterial surface and the labeled anti-preS IgG polyclonal antibodies from immunized serum were used as "Tester" to enrich preS-specific mimotopes. Bacterial clones were identified out of this pool through an "antigen-independent" procedure only using both different sera samples. After four rounds of sub-FACS screening, 41 out of 50 bacterial clones were identified as reacting with the immunized serum but not reacting with the pre-immune one. Two motif sequences HQLD and DPAF were obtained from 13 clones. Immunization of mice with two representative bacterial clones elicited a strong specific response against native preS antigen in comparison with the control. This technique may provide a useful technology platform for high-throughput screening of disease-related epitope which is of importance to develop vaccine against some infectious diseases whose pathogen or immunodominant antigen is still unknown.

Animals↗

PubMed2004

Salutary effects of attenuation of angiotensin II on coronary perivascular fibrosis associated with insulin resistance and obesity.

Obesity and insulin resistance confer increased risk for accelerated coronary disease and cardiomyopathic phenomena. We have previously shown that inhibition of angiotensin-converting enzyme (ACE) prevents coronary perimicrovascular fibrosis in genetically obese mice that develop insulin resistance. This study was performed to elucidate mechanism(s) implicated and to determine the effects of attenuation of angiotensin II (Ang) II. Genetically obese ob/ob mice were given ACE inhibitor (temocapril) or Ang II type 1 (AT(1)) receptor blocker (olmesartan) from 10 to 20 weeks. Cardiac expressions of plasminogen activator inhibitor (PAI)-1, the major physiologic inhibitor of fibrinolysis, and transforming growth factor (TGF)-beta(1), a prototypic profibrotic molecule, were determined and extent of perivascular coronary fibrosis was measured. Twenty-week-old obese mice exhibited increased plasma levels of PAI-1 and TGF-beta(1) compared with the values in lean counterpart. Perivascular coronary fibrosis in arterioles and small arteries was evident in obese mice that also showed increased left ventricular collagen as measured by hydroxyproline assay. Immunohistochemistry confirmed the deposition of perivascular type 1 collagen. Markedly increased PAI-1 and TGF-beta were seen immunohistochemically in coronary vascular wall and confirmed by western blotting. When obese mice were treated with temocapril or olmesartan from 10 to 20 weeks, both were equally effective and prevented increases in perivascular fibrosis, plasma PAI-1 and TGF-beta(1), left ventricular collagen and mural immunoreactivity for PAI-1, TGF-beta and collagen type 1. The c-Jun NH(2)-terminal kinase (JNK) activity was elevated in the left ventricle of obese mice (western) and blocked by temocapril and olmesartan. Ang II-mediated upregulation of PAI-1 and TGF-beta(1) with collagen deposition may explain the mechanism of perivascular fibrosis in obese mice. ACE inhibition and blockade of AT(1) receptor may prevent coronary perivascular fibrosis and collagen deposition even before development of overt diabetes. JNK activation may be a mediator of obesity-related cardiac dysfunction and a potential therapeutic target.

Angiotensin II↗

PubMed2004

Transgene manipulation in zebrafish by using recombinases.

Although much remains to be done, our results to date suggest that efficient and precise genome engineering in zebrafish will be possible in the future by using Cre recombinase and SB transposase in combination with their respective target sites. In this study, we provide the first evidence that Cre recombinase can mediate effective site-specific deletion of transgenes in zebrafish. We found that the efficiency of target site utilization could approach 100%, independent of whether the target site was provided transiently by injection or stably within an integrated transgene. Microinjection of Cre mRNA appeared to be slightly more effective for this purpose than microinjection of Cre-expressing plasmid DNA. Our work has not yet progressed to the point where SB-mediated mobilization of our transgene constructs would be observed. However, a recent report has demonstrated that SB can enhance transgenesis rates sixfold over conventional methods by efficiently mediating multiple single-copy insertion of transgenes into the zebrafish genome (Davidson et al., 2003). Therefore, it seems likely that a combined system should eventually allow both SB-mediated transgene mobilization and Cre-mediated transgene modification. Our goal is to validate methods for the precise reengineering of the zebrafish genome by using a combination of Cre-loxP and SB transposon systems. These methods can be used to delete, replace, or mobilize large pieces of DNA or to modify the genome only when and where required by the investigator. For example, it should be possible to deliver particular RNAi genes to well-expressed chromosomal loci and then exchange them easily with alternative RNAi genes for the specific suppression of alternative targets. As a nonviral vector for gene therapy, the transposon component allows for the possibility of highly efficient integration, whereas the Cre-loxP component can target the integration and/or exchange of foreign DNA into specific sites within the genome. The specificity and efficiency of this system also make it ideal for applications in which precise genome modifications are required (e.g., stock improvement). Future work should establish whether alternative recombination systems (e.g., phiC31 integrase) can improve the utility of this system. After the fish system is fully established, it would be interesting to explore its application to genome engineering in other organisms.

Animals↗