Isolation, genome analysis and comparison of a novel parainfluenza virus 5 from a Siberian tiger (Panthera tigris).

Paramyxoviruses are important pathogens affecting various animals, including mammals and humans. Parainfluenza virus 5 (PIV5)-a member of the family Paramyxoviridae-is a major threat to the health of mammals and humans. However, studies on terrestrial wild animals infected with PIV5 are scanty. In this study, we utilized reverse transcription PCR to detect PIV5 infection in the visceral organ tissues of a Siberian tiger (Panthera tigris ssp. altaica) with vomiting, diarrhea, and dyspnea before its death. A novel PIV5 (named SR strain) with a slowly progressive cytopathic effect was isolated in Vero cells and validated using a transmission electron microscope. Full-length sequencing and analysis revealed that the whole genome of the PIV5 SR strain contained 15,246 nucleotides (nt) and seven non-overlapping genes (3'-N-V/P-M-F-SH-HN-L-5') encoding eight proteins. Phylogenetic analysis of three PIV5 strains identified in the same zoo confirmed that PIV5 strains SR and ZJQ-221 shared the closest genetic relationship as they were clustered in the same branch, while the recently found Siberian tiger strain SZ2 kept a certain distance and formed a relatively unique branch. Furthermore, mutations of nt and amino acids (aa) between strains ZJQ-221, SR, and SZ2 were identified. In summary, we report the identification and genomic characterization of a novel PIV5 strain SR isolated in a Siberian tiger, which may help future research on interspecific transmission mechanisms.

Identification and characterization of biomarkers associated with endoplasmic reticulum protein processing in cerebral ischemia-reperfusion injury.

Background: Cerebral ischemia (CI), ranking as the second leading global cause of death, is frequently treated by reestablishing blood flow and oxygenation. Paradoxically, this reperfusion can intensify tissue damage, leading to CI-reperfusion injury. This research sought to uncover biomarkers pertaining to protein processing in the endoplasmic reticulum (PER) during CI-reperfusion injury. Methods: We utilized the Gene Expression Omnibus (GEO) dataset GSE163614 to discern differentially expressed genes (DEGs) and single out PER-related DEGs. The functions and pathways of these PER-related DEGs were identified via Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Core genes were pinpointed through protein-protein interaction (PPI) networks. Subsequent to this, genes with diagnostic relevance were distinguished using external validation datasets. A single-sample gene-set enrichment analysis (ssGSEA) was undertaken to pinpoint genes with strong associations to hypoxia and apoptosis, suggesting their potential roles as primary inducers of apoptosis in hypoxic conditions during ischemia-reperfusion injuries. Results: Our study demonstrated that PER-related genes, specifically ADCY5, CAMK2A, PLCB1, NTRK2, and DLG4, were markedly down-regulated in models, exhibiting a robust association with hypoxia and apoptosis. Conclusion: The data indicates that ADCY5, CAMK2A, PLCB1, NTRK2, and DLG4 could be pivotal genes responsible for triggering apoptosis in hypoxic environments during CI-reperfusion injury.

Genomic evolution of island birds from the view of the Swinhoe's pheasant (Lophura swinhoii).

Island endemic birds account for the majority of extinct vertebrates in the past few centuries. To date, the evolutionary characteristics of island endemic bird's is poorly known. In this research, we de novo assembled a high-quality chromosome-level reference genome for the Swinhoe's pheasant, which is a typical endemic island bird. Results of collinearity tests suggest rapid ancient chromosome rearrangement that may have contributed to the initial species radiation within Phasianidae, and a role for the insertions of CR1 transposable elements in rearranging chromosomes in Phasianidae. During the evolution of the Swinhoe's pheasant, natural selection positively selected genes involved in fecundity and body size functions, at both the species and population levels, which reflect genetic variation associated with island adaptation. We further tested for variation in population genomic traits between the Swinhoe's pheasant and its phylogenetically closely related mainland relative the silver pheasant, and found higher levels of genetic drift and inbreeding in the Swinhoe's pheasant genome. Divergent demographic histories of insular and mainland bird species during the last glacial period may reflect the differing impact of insular and continental climates on the evolution of species. Our research interprets the natural history and population genetic characteristics of the insular endemic bird the Swinhoe's pheasant, at a genome-wide scale, provides a broader perspective on insular speciation, and adaptive evolution and contributes to the genetic conservation of island endemic birds.

Development of a reverse transcription loop-mediated isothermal amplification based clustered regularly interspaced short palindromic repeats Cas12a assay for duck Tembusu virus.

Duck Tembusu virus (DTMUV) is an emerging pathogen that poses a serious threat to the duck industry in China. Currently, polymerase chain reaction (PCR), quantitative PCR (qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) are commonly used for DTMUV detection. However, these methods require complex steps and special equipment and easily cause false-positive results. Therefore, we urgently need to establish a simple, sensitive and specific method for the clinical field detection of DTMUV. In this study, we developed an RT-LAMP-based CRISPR-Cas12a assay targeting the C gene to detect DTMUV with a limited detection of 3 copies/µL. This assay was specific for DTMUV without cross-reaction with other common avian viruses and only required some simple pieces of equipment, such as a thermostat water bath and blue/UV light transilluminator. Furthermore, this assay showed 100% positive predictive agreement (PPA) and negative predictive agreement (NPA) relative to SYBR Green qPCR for DTMUV detection in 32 cloacal swabs and 22 tissue samples, supporting its application for clinical field detection.

Pathogenicity, tissue tropism and potential vertical transmission of SARSr-CoV-2 in Malayan pangolins.

Malayan pangolin SARS-CoV-2-related coronavirus (SARSr-CoV-2) is closely related to SARS-CoV-2. However, little is known about its pathogenicity in pangolins. Using CT scans we show that SARSr-CoV-2 positive Malayan pangolins are characterized by bilateral ground-glass opacities in lungs in a similar manner to COVID-19 patients. Histological examination and blood gas tests are indicative of dyspnea. SARSr-CoV-2 infected multiple organs in pangolins, with the lungs the major target, and histological expression data revealed that ACE2 and TMPRSS2 were co-expressed with viral RNA. Transcriptome analysis indicated that virus-positive pangolins were likely to have inadequate interferon responses, with relative greater cytokine and chemokine activity in the lung and spleen. Notably, both viral RNA and viral proteins were detected in three pangolin fetuses, providing initial evidence for vertical virus transmission. In sum, our study outlines the biological framework of SARSr-CoV-2 in pangolins, revealing striking similarities to COVID-19 in humans.

Virus diversity, wildlife-domestic animal circulation and potential zoonotic viruses of small mammals, pangolins and zoo animals.

Wildlife is reservoir of emerging viruses. Here we identified 27 families of mammalian viruses from 1981 wild animals and 194 zoo animals collected from south China between 2015 and 2022, isolated and characterized the pathogenicity of eight viruses. Bats harbor high diversity of coronaviruses, picornaviruses and astroviruses, and a potentially novel genus of Bornaviridae. In addition to the reported SARSr-CoV-2 and HKU4-CoV-like viruses, picornavirus and respiroviruses also likely circulate between bats and pangolins. Pikas harbor a new clade of Embecovirus and a new genus of arenaviruses. Further, the potential cross-species transmission of RNA viruses (paramyxovirus and astrovirus) and DNA viruses (pseudorabies virus, porcine circovirus 2, porcine circovirus 3 and parvovirus) between wildlife and domestic animals was identified, complicating wildlife protection and the prevention and control of these diseases in domestic animals. This study provides a nuanced view of the frequency of host-jumping events, as well as assessments of zoonotic risk.

Population genomic analysis provides evidence of the past success and future potential of South China tiger captive conservation.

BACKGROUND: Among six extant tiger subspecies, the South China tiger (Panthera tigris amoyensis) once was widely distributed but is now the rarest one and extinct in the wild. All living South China tigers are descendants of only two male and four female wild-caught tigers and they survive solely in zoos after 60 years of effective conservation efforts. Inbreeding depression and hybridization with other tiger subspecies were believed to have occurred within the small, captive South China tiger population. It is therefore urgently needed to examine the genomic landscape of existing genetic variation among the South China tigers. RESULTS: In this study, we assembled a high-quality chromosome-level genome using long-read sequences and re-sequenced 29 high-depth genomes of the South China tigers. By combining and comparing our data with the other 40 genomes of six tiger subspecies, we identified two significantly differentiated genomic lineages among the South China tigers, which harbored some rare genetic variants introgressed from other tiger subspecies and thus maintained a moderate genetic diversity. We noticed that the South China tiger had higher FROH values for longer runs of homozygosity (ROH > 1 Mb), an indication of recent inbreeding/founder events. We also observed that the South China tiger had the least frequent homozygous genotypes of both high- and moderate-impact deleterious mutations, and lower mutation loads than both Amur and Sumatran tigers. Altogether, our analyses indicated an effective genetic purging of deleterious mutations in homozygous states from the South China tiger, following its population contraction with a controlled increase in inbreeding based on its pedigree records. CONCLUSIONS: The identification of two unique founder/genomic lineages coupled with active genetic purging of deleterious mutations in homozygous states and the genomic resources generated in our study pave the way for a genomics-informed conservation, following the real-time monitoring and rational exchange of reproductive South China tigers among zoos.

Edaravone combined with Shuxuening versus edaravone alone in the treatment of acute cerebral infarction: A systematic review and meta-analysis.

BACKGROUND: Shuxuening injection (SXN) is a traditional Chinese medicine used in the treatment of cardiovascular diseases. Whether it can provide better outcomes when combined with edaravone injection (ERI) for the treatment of acute cerebral infarction is not well determined. Therefore, we evaluated the efficacy of ERI combined with SXN versus that of ERI alone in patients with acute cerebral infarction. METHODS: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang electronic databases were searched up to July 2022. Randomized controlled trials comparing the outcomes of efficacy rate, neurologic impairment, inflammatory factors, and hemorheology were included. Odds ratio or standard mean difference (SMD) with corresponding 95% confidence intervals (CIs) were used to present the overall estimates. The quality of the included trials was evaluated by the Cochrane risk of bias tool. The study was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses. RESULTS: Seventeen randomized controlled trials were included consisting of 1607 patients. Compared to ERI alone, treatment with ERI plus SXN had a greater effective rate than ER alone (odds ratio = 3.94; 95% CI: 2.85, 5.44; I2 = 0%, P < .00001), a lower National Institute of Health Stroke Scale (SMD= -1.39; 95% CI: -1.73, -1.05; I2 = 71%, P < .00001), lower neural function defect score (SMD= -0.75; 95% CI: -1.06,-0.43; I2 = 67%, P < .00001), and lower level of neuron-specific enolase (SMD= -2.10; 95% CI: -2.85, -1.35; I2 = 85%, P < .00001). ERI plus SXN treatment provided significant improvements in whole blood high shear viscosity (SMD = -0.87; 95% CI: -1.17, -0.57; I2 = 0%, P < .00001), and whole blood low shear viscosity (SMD = -1.50; 95% CI: -1.65, -1.36; I2 = 0%, P < .00001) compared to ERI alone. CONCLUSION: ERI plus SXN showed better efficacy than ERI alone for patients with acute cerebral infarction. Our study provides evidence supporting the application of ERI plus SXN for acute cerebral infarction.

Porphyromonas gingivalis induces periodontitis, causes immune imbalance, and promotes rheumatoid arthritis.

Periodontitis induced by bacteria especially Porphyromonas gingivalis (P. gingivalis) is the most prevalent microbial disease worldwide and is a significant risk factor for systemic diseases such as rheumatoid arthritis (RA). RA and periodontitis share similar clinical and pathologic features. Moreover, the prevalence of RA is much higher in patients with periodontitis than in those without periodontitis. To explore the immunologic mechanism of periodontitis involved in RA, we established a mouse model of periodontitis and then induced RA. According to the results of paw thickness, arthritis clinical score, arthritis incidence, microscopic lesion using H&E staining, and micro-CT analysis, periodontitis induced by P. gingivalis promoted the occurrence and development of collagen-induced arthritis (CIA) in mice. Furthermore, periodontitis enhanced the frequency of CD19+ B cells, Th17, Treg, gMDSCs, and mMDSCs, whereas down-regulated IL-10 producing regulatory B cells (B10) in CIA mice preinduced for periodontitis with P. gingivalis. In vitro stimulation with splenic cells revealed that P. gingivalis directly enhanced differentiation of Th17, Treg, and mMDSCs but inhibited the process of B cell differentiation into B10 cells. Considering that adoptive transfer of B10 cells prevent RA development, our study, although preliminary, suggests that down-regulation of B10 cells may be the key mechanism that periodontitis promotes RA as the other main immune suppressive cells such as Treg and MDSCs are up-regulated other than down-regulated in group of P. gingivalis plus CIA.

Pathogenicity and transmissibility of a novel respirovirus isolated from a Malayan pangolin.

The identification of SARS-CoV-2-like viruses in Malayan pangolins (Manis javanica) has focused attention on these endangered animals and the viruses they carry. We successfully isolated a novel respirovirus from the lungs of a dead Malayan pangolin. Similar to murine respirovirus, the full-length genome of this novel virus was 15 384 nucleotides comprising six genes in the order 3'-(leader)-NP-P-M-F-HN-l-(trailer)-5'. Phylogenetic analysis revealed that this virus belongs to the genus Respirovirus and is most closely related to murine respirovirus. Notably, animal infection experiments indicated that the pangolin virus is highly pathogenic and transmissible in mice, with inoculated mice having variable clinical symptoms and a fatality rate of 70.37 %. The virus was found to replicate in most tissues with the exception of muscle and heart. Contact transmission of the virus was 100 % efficient, although the mice in the contact group displayed milder symptoms, with the virus mainly being detected in the trachea and lungs. The isolation of a novel respirovirus from the Malayan pangolin provides new insight into the evolution and distribution of this important group of viruses and again demonstrates the potential infectious disease threats faced by endangered pangolins.

Identification of Amblyomma javanense and detection of tick-borne Ehrlichia spp. in confiscated Malayan Pangolins.

Due to habitat destruction and illegal hunting and trade, the number of pangolins has been sharply reduced. To protect pangolins from extinction, relevant departments are combined and active action have been taken. A total of 21 confiscated Malayan pangolins were rescued in 2019, but died continuously for unknown reasons. This study aimed to investigate the reasons for the death of these pangolin and rescue them. 19 of the 21 confiscated pangolins had ticks on their body integument. A total of 303 ticks were collected and identified as Amblyomma javanense (A. javanense) according to their morphology and the sequences of 16S rRNA and internal transcribed spacer 2 (ITS2). There were multi-organ damages in the dead pangolins, especially congestion and hemorrhage in lung, heart and kidney and inflammation of which were observed using HE staining. Pathogens' nucleic acid detection showed ticks were only positive for Ehrlichia spp, with 56.7% positive rate of collected ticks (127/224), which was further confirmed in tissues from dead pangolins. Our findings confirm that ehrlichiosis caused by Ehrlichia spp. from A. javanense might accelerate the confiscated pangolin's death. More attention should be payed to tick-elimination work and the diagnoses and treatment of tick-borne diseases in the follow-up rescue operation.

Outbreak and genotyping of canine distemper virus in captive Siberian tigers and red pandas.

In this study, four canine distemper virus (CDV) strains were isolated from captive Siberian tigers (Panthera tigris altaica) and red pandas (Ailurus fulgens) during two separate CDV outbreaks in a zoo in Guangdong province, China. Sequence alignment and phylogenetic analyses based on the full-length hemagglutinin (H) and fusion (F) genes showed that they were closely identical to genotype Asia-1. Prior to confirmation of CDV in Siberian tigers, to control spread of the disease, a live attenuated combination CDV vaccine was used among almost all carnivore animals except for red pandas in which another recombinant combination CDV vaccine was used. However, about two months later, CDV re-emerged and caused the death among red pandas. Based on the vaccination records, the live combination vaccine could be considered an ideal weapon against CDV in zoo carnivore animals. Although the recombinant combination CDV vaccine was safe for red pandas, its protection effectiveness remains to be further investigated. Moreover, according to the outbreak interval time and sequence characterization, we suspected that stray cats circulating in the zoo were the intermediate host, which contributed to CDV spread from stray dogs to zoo animals. This study revealed the importance of vaccination and biosecurity for zoo animals.

[Observation of genetic diversity in dental plaque of elder people with root caries].

PURPOSE: Bacterial community in dental plaque of elder people was analyzed to learn about the microhabitat composition and diversity. METHODS: Dental plaque samples were collected from 25 elders. PCR-based denaturing gradient gel electrophoresis (PCR-DGGE) was used to evaluate the microbial diversity by displaying PCR-generated 16SrDNA fragments that migrate at different distances, reflecting the different sequence of fragment. SPSS12.0 software was used to analyze the variance of genotypes between different groups of bacteria. RESULTS: Genotypes of bacteria in dental plaques in the root caries group was significantly more than the other two groups. Crown caries group and caries-free group had no significant difference. CONCLUSIONS: The genetic diversity of the dental plaque microflora in the root caries group is significantly higher than coronal caries group and caries-free group.

Pathogenicity in quails and mice of H5N1 highly pathogenic avian influenza viruses isolated from ducks.

In our study, the pathogenicity of H5N1 influenza A viruses circulating in waterfowls in Southern China was investigated. Three H5N1 highly pathogenic avian influenza (HPAI) viruses isolated from ducks, A/Duck/Guangdong/383/2008(DK383), A/Duck/Guangdong/378/2008(DK378) and A/Duck/Guangdong/212/2004(DK212) were inoculated at 10(6) fifty-percent egg infectious doses (EID(50)) into ducks, quails and mice and showed varying levels of pathogenicity. In ducks, the mortality rates ranged from 0 to 60% and the mean death time (MDT) was 0-6.7 days post-inoculation (DPI). While the viruses were highly pathogenic in quails, resulting in 83.3-100% mortality and the MDT of 2.3-3 DPI, they were completely lethal in mice (100% mortality). The viruses replicated in many organs of ducks and quails and were found in the brain, and kidney, lung and spleen of the mice. Phylogenetic analysis revealed that DK383 and DK378 viruses of clade 2.3.2 belonged to genotype 11, while DK212 virus of clade 9 was genotype 3. Our study illustrated H5N1 influenza viruses within Clade 2.3.2 and 9 from duck in Southern China had very highly pathogenicity to Japanese quails and BALB/c mice, but viruses within Clade 2.3.2 had more highly lethality than those of clade 9 to Muscovy ducks. Therefore, they had posed a continued challenge for disease control and public health.

[Analysis of community composition in dental plaque of elder people with root caries].

OBJECTIVE: To analyze the community in dental plaque of elder people with root caries. METHODS: Total DNAs were extracted from the root caries dental plaques of nine elders over 60 years of age. Polymerase chaid reaction-based denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the microbial composition, DGGE bands were excised from the gels for sequencing and identification. RESULTS: The dominant genus in root caries dental plaque of elder people were: Acinetobacte [0.9% (1/114)], Actinobaculum [1.8% (2/114)], Actinomyces [15.8% (18/114)], Aggregatibacter [0.9% (1/114)], Capnocytophaga [14.0% (16/114)], Corynebacterium [0.9% (1/114)], Haemophilus [0.9% (1/114)], Mobiluncus [0.9% (1/114)], Naxibacter [0.9% (1/114)], Neisseriaceae [10.5% (12/114)], Porphyromonas [0.9% (1/114)], Prevotella [12.3% (14/114)], Selenomonas [6.1% (7/114)], Staphylococcus [1.8% (2/114)], Oralis streptococcus [6.1% (7/114)], Mutans streptococcu [7.9% (9/114)], Tannerella [0.9% (1/114)], Treponema [1.8% (2/114)], Veillonella [10.5% (12/114)] and two uncultured unknown genus [1.8% (2/114)]. Uncultred genotypes accounted for 19.30% of the total. Gram-positive bacteria genotype accounted for 31.6% (36/114), and Gram-negative bacteria genotype accounted for 66.7% (76/114). CONCLUSIONS: There were many bacteria genotypes in root caries dental plaque in the elderly, which were widely distributed. Gram-negative bacteria accounted for the majority. Genotype-specific pathogenic bacteria were not found.

Analysis of community composition in dental plaque of elder people with root caries / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the community in dental plaque of elder people with root caries.</p><p><b>METHODS</b>Total DNAs were extracted from the root caries dental plaques of nine elders over 60 years of age. Polymerase chaid reaction-based denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the microbial composition, DGGE bands were excised from the gels for sequencing and identification.</p><p><b>RESULTS</b>The dominant genus in root caries dental plaque of elder people were: Acinetobacte [0.9% (1/114)], Actinobaculum [1.8% (2/114)], Actinomyces [15.8% (18/114)], Aggregatibacter [0.9% (1/114)], Capnocytophaga [14.0% (16/114)], Corynebacterium [0.9% (1/114)], Haemophilus [0.9% (1/114)], Mobiluncus [0.9% (1/114)], Naxibacter [0.9% (1/114)], Neisseriaceae [10.5% (12/114)], Porphyromonas [0.9% (1/114)], Prevotella [12.3% (14/114)], Selenomonas [6.1% (7/114)], Staphylococcus [1.8% (2/114)], Oralis streptococcus [6.1% (7/114)], Mutans streptococcu [7.9% (9/114)], Tannerella [0.9% (1/114)], Treponema [1.8% (2/114)], Veillonella [10.5% (12/114)] and two uncultured unknown genus [1.8% (2/114)]. Uncultred genotypes accounted for 19.30% of the total. Gram-positive bacteria genotype accounted for 31.6% (36/114), and Gram-negative bacteria genotype accounted for 66.7% (76/114).</p><p><b>CONCLUSIONS</b>There were many bacteria genotypes in root caries dental plaque in the elderly, which were widely distributed. Gram-negative bacteria accounted for the majority. Genotype-specific pathogenic bacteria were not found.</p>

[Cloning and analysis of full-length genes of a H9N2 subtype avian influenza virus isolated from Guangdong].

Eight full-length genes of an avian influenza virus Chinese isolate of H9N2 subtype, A/Chicken/Guangdong/HL/2006 (H9N2) (abbreviated as Ck/GD/HL/06), were amplified by RT-PCR, including the 5' and 3' non-coding region. All the genes were cloned and sequenced. The phylogenetic analysis results showed the HA gene of Ck/GD/HL/06 was located in the same phylogenetic clade as Dk/HK/Y280/97 (H9N2), while the Dk/HK/Y280/97-like viruses had been predominately isolated from chickens in mainland China. After the analysis of glycosylation sites and receptor-binding sites in the HA, it was shown that the HA of Ck/GD/HL/06 exhibited the common feature of H9 subtype avian influenza virus isolated from China, but the leucine (Leu) residue at the amino acid position 226 indicated the potential of binding with SA alpha,2-6 receptor. The three internal genes of Ck/GD/HL/06 (PB1, PA and NP) had the highest nucleotide identity with A/Viet Nam/1203/2004 (abbreviated A/VN/1203/04) isolate, which was shown to be transmitted from chickens to human and caused lethal infection in human. No analogous H9N2 strains was reported in previous studies. Based on the high similarity of Ck/GD/HL/06 three genes to A/VN/1203/04, it was suggested that the possibility of generating new highly pathogenic H5N1 AIVs by recombination was worthy of our attention. Further studies should be needed for molecular epidemiologic surveillance of H9N2 AIV in the south China for a long time.

[Molecular analysis of an avian influenza virus isolate of H5N2 subtype from parrot].

In 2005, an avian influenza virus stain was isolated from Parrot in Guangdong, which was then genotyped as H5N2 subtype and designated as A/Parrot/Guangdong/268/2005. According to the current OIE definition on the low-pathogenicity of avian influenza virus, the strain was recognized as a low pathogenic avian influenza virus due to the presence of one basic amino acid residue at the HA cleavage site. Some molecular characteristics of the virus, such as potential glycosylation sites in HA and NA, receptor binding sites of HA, and drug resistance site of NA, showed no variations. To analyze molecular evolution of this strain, we selected the sequences of H5N2 subtype AIVs from GenBank and established the phylogenetic trees. Our results indicated that this strain shared the highest homologies with the H5N2 LPAI isolate A/Pheasant/NJ/1355/1998-like. Phylogenic analysis revealed the isolate, together with A/Chicken/Pennsylvania/1/1983 (H5N2), belonged to America lineages and clustered with A/Pheasant/NJ/1355/1998-like.

[Quantitative evaluation of residual endodontic microorganisms after mechanical root canal preparation different chemical preparations by real-time PCR].

PURPOSE: To establish a quick, sensitive method for quantifying root canal flora and investigate the effects of different root canal preparations on the pathogenic bacteria at RNA level. METHODS: A total of 24 single-rooted teeth with chronic apical periodontitis were selected and prepared using 3% H2O2 combined with 1% NaClO, EDTA combined with 3% H(2)O(2),1% NaClO, respectively,the samples were taken before and after root canal preparation. After isolation of total RNA from the root canal samples, cDNA was synthesized by reverse transcription, and detected by real-time PCR. The data were analyzed with SAS 6.12 software package. RESULTS: The number of bacteria in the root canal reduced dramatically after mechanical preparation and irrigated using 3% H(2)O(2) and 1% NaClO(P<0.01). Further combined with EDTA, its effect was better than that of simply irrigated using 3% H(2)O(2) and 1% NaClO(P<0.05). CONCLUSIONS: Real-time PCR can be employed in the identification of bacteria flora in the root canal, both methods of root canal preparation can effectively reduce the number of bacteria flora.

[Comparison of the sucrose dependent cell adherence of Streptococcus mutans isolates from caries-active and caries-free children].

PURPOSE: To study the sucrose dependent cell adhesive ability of Streptococcus mutans islolated from the caries-active and caries-free children. METHODS: 60 isolated Streptococcus mutans strains were selected and identified from the dental plaque of 10 caries-active children and 10 caries-free children (3 to 5 years), in which 39 strains were from caries-active group(dmfs>or=6) and 21 strains from caries-free group(dmfs=0). With the use of ultraviolet spectrophotometer, the sucrose dependent cell adherence to glass wall of the sucrose-containing testing tubes was analyzed. One-way ANOVA was used by SPSS12.0 software package to determine the statistical difference of the adhesive ability between the two groups. RESULTS: The average adhesive ratio of the Streptococcus mutans strains isolated from caries-active group was 55.49%+26.16% in the 1% sucrose-containing culture medium, while the average adhesive ratio of the Streptococcus mutans strains isolated from caries-free group was 27.01%+18.39%. The difference between the two groups was statistically significant (P<0.01). CONCLUSION: In the sucrose-containing circumstance, the sucrose dependent cell adhesive ability of the Streptococcus mutans isolated from the caries-active children was significantly higher than that from the caries-free children. This indicated that the adhesive ability may be related to the caries-causing tendency.