Identification and Pathogenicity Analysis of the Pathogen Causing Spotted Spleen in Muscovy Duck.

Since September 2020, the clinical symptoms of Muscovy duck spleen spots have appeared in Guangdong, Guangxi, Jiangxi, Hunan, Hubei, and other provinces, resulting in a large number of Muscovy duck deaths and great economic losses. The absence of the typical clinical symptoms caused by pathogenic microorganisms makes the cause of the spotted spleen a mystery. High-throughput sequencing results suggested that Riemerella anatipestifer (R. anatipestifer) may be the pathogen. Then, R. anatipestifer was regarded as the research target for isolation, identification, and pathogenicity assessment. After biochemical test, PCR amplification, and serotype determination, it was confirmed that the isolated strain CZG-1 was serotype 15 R. anatipestifer. Typical spotted spleen symptoms were observed after CZG-1 infection. Furthermore, drug sensitivity assays showed the similar drug-resistant spectrum of R. anatipestifer serotype 15 to other serotypes; for example, all test strains were resistant to polymyxin, gentamicin, and neomycin. The CZG-1 strain has high pathogenicity, and its lethal dose of 50% (LD50) is 35.122 CFU/ml. Virulence gene determination showed that the CZG-1 strain had at least five virulence genes, bioF, TSS9-1, TSS9-2, PncA, and 0373Right. Above all, this study identified and proved that the pathogen of spotted spleen in ducks was R. anatipestifer serotype 15, which caused death of ducks without the typical symptoms of bacterial infection. The results of this study enriched the knowledge of symptom after R. anatipestifer infection, provided a reference to the identification of the pathogen of spotted spleen, and provided theoretical basis for prevention and control of spotted spleen.

Comparative genomic analysis of Mycoplasma anatis strains.

BACKGROUND: The Gram-negative intracellular bacterium Mycoplasma anatis is a pathogen of respiratory infectious diseases in ducks and has caused significant economic losses in the poultry industry. OBJECTIVE: This study, as the first report of the structure and function of the pan-genome of Mycoplasma anatis, may provide a valuable genetic basis for many aspects of future research on the pathogens of waterfowl. METHODS: We sequenced the whole genomes of 15 Mycoplasma anatis isolated from ducks in China. Draft genome sequencing was carried out and whole-genome sequencing was performed by the sequencers of the PacBio Sequel and an IonTorrent Personal Genome Machine (PGM). Then the common genic elements of protein-coding genes, tRNAs, and rRNAs of Mycoplasma anatis genomes were predicted by using the pipeline Prokka v1.13.7. To investigate homologous protein clusters across Mycoplasma anatis genomes, we adopted Roary v3.13.0 to cluster orthologous genes (OGs) based on the following criteria. RESULTS: We obtained one complete genome and 14 genome sketches. Microbial mobile genetic element analysis revealed the distribution of insertion sequences (IS30, IS3, and IS1634), prophage regions, and CRISPR arrays in the genome of Mycoplasma anatis. Comparative genomic analysis decoded the genetic components and functional classification of the pan-genome of Mycoplasma anatis that comprised 646 core genes, 231 dispensable genes and among them 110 was strain-specific. Virulence-related gene profiles of Mycoplasma anatis were systematically identified, and the products of these genes included bacterial ABC transporter systems, iron transport proteins, toxins, and secretion systems. CONCLUSION: A complete virulence-related gene profile of Mycoplasma anatis has been identified, most of the genes are highly conserved in all strains. Sequencing results are relevant to the molecular mechanisms of drug resistance, adaptive evolution of pathogens, population structure, and vaccine development.

[MiR-99a inhibits proliferation of oral squamous cell carcinoma by targeting mTOR pathway].

PURPOSE: To investigate miR-99a expression and its effect on proliferation of oral squamous cell carcinoma (OSCC). METHODS: miRNA microarrays associated with OSCC were identified in GEO database. The expression levels of miR-99a were detected in 63 OSCC tissues and adjacent normal tissues and cell lines. The relationship between clinicopathological parameters and miR-99a expression was analyzed by using ANOVA analysis. The ability of cell growth and clone formation were examined in SCC9 and SCC25 cells transfected with miR-99a mimics. The target genes of miR-99a were predicted by Targetscan software. There resulting data were analyzed using SPSS 19.0 software package. RESULTS: The differently expressed miRNAs were analyzed based on GSE103931 microarray. miR-99a was significantly downregulated in OSCC tissues and cell lines. miR-99a expression was significantly associated with T stage, pathological grading and patients' prognosis. miR-99a overexpression inhibited OSCC cell proliferation and clone formation, while miR-99a inhibition contributed to decreased proliferation and clone formation ability. In addition, miR-99a combined with mTOR gene's 3'UTR was negatively correlated with mTOR expression in OSCC tissues. CONCLUSIONS: miR-99a functions as a tumor suppressor in OSCC and inhibits OSCC cell proliferation by targeting mTOR.

The protective efficacy of specific egg yolk immunoglobulin Y(IgY) against Riemerella Anatipestifer infections.

Riemerella anatipestifer (RA) is the significant pathogen of septicemia and duck infectious serositis, diseases which can result in high mortality for ducklings. However, these diseases are difficult to treat because of the bacteria's broad resistance to multiple drugs. The purpose of this study was to produce a specific egg yolk immunoglobulin Y (IgY) targeted to RA, and to evaluate the protective efficacy of this IgY against RA infection. An RA-inactivated vaccine was produced via centrifugation and formalin treatment, using the most predominant serotype 2 wild-type strains in terms of worldwide prevalence. Anti-RA IgY was produced by immunizing Beijing Red No.1 hens with the inactivated vaccine. Enzyme-linked immunosorbent assays showed that the titer levels of anti-RA IgY antibodies increased significantly after exposure. Specific IgY isolated and purified from yolks effectively inhibited the growth of RA in the antibacterial activity assay, which revealed an 80 % reduction of bacteria populations. Animal experiments showed that duckling survival rates were able to reach up to 100 % after the ducklings were treated with 10 mg intramuscular injections of anti-RA IgY from 1 to 12 h after infection. However, the survival rates of ducklings treated with 30 mg of nonspecific IgY at 1 h after infection were 0%. Additionally, ducklings injected once with anti-RA IgY received complete protection in the first week, but the efficacy of this protection almost entirely disappeared after two weeks. The results suggested that specific anti-RA IgY has the potential to improve the degree of protection and responsiveness of ducklings to RA infections and provide them with passive immunity to RA. With further study, this is expected to become a new method for controlling RA infections.

[Clinical study on united crowns or bridges for restoration of posterior teeth with insufficient maxillary bone by means of maxillary tuberosity dental implants].

PERPOSE: To evaluate the clinical effect of united crowns or bridges for restoration of posterior teeth with insufficient maxillary bone by means of tilted dental implants. METHODS: Patients who underwent dental implant surgery in posterior teeth with insufficient maxillary bone were collected and divided into two groups (40 in each group). Patients in the experimental group were treated with titled dental implantation, while patients in the control group were treated with maxillary sinus lifting. Implant retention, marginal bone loss, incidence of adverse reactions, time needed for implantation and cost were recorded and analyzed with SPSS 19.0 software package. RESULTS: After follow up of 2 year, the experimental group had a cumulative survival rate of 100%, marginal bone resorption was (0.31±0.27)mm on average, no sinusitis and massive haemorrhage were noted, The control group had a cumulative survival rate of 96.43%, marginal bone resorption was (0.28±0.26) mm on average, sinusitis and massive haemorrhage occurred in 9.5%,4.8% of patients, the difference was not statistically significant（P＞0.05）. In the experimental group, maxillary sinus mucosa perforation and postoperative pain occurred in 0%,7.5% of patients, duration of operation was （30.55±8.21）min, average cost of each implant was （6.9±0.5）thousand RMB; while in the control group, maxillary sinus mucosa perforation and postoperative pain occurred in 14.3%,28.6% of patients, duration of operation was （50.32±10.80）min, average cost of each implant was (0.98±0.06) thousand RMB, the difference was significant（P＜0.05）. CONCLUSIONS: It is feasible to use united crowns or bridges for restoration of posterior teeth with insufficient maxillary bone by means of maxillary tuberosity dental implants.

Influence of hormones on osseointegration in dental implant / 口腔疾病防治

@#Osseointegration plays an important role in the functions and aesthetics of dental implant. This paper focus on the hormones closely related to the bone metabolism, including glucocorticoid, parathyroid hormone, calcitonin, melatonin, and oestrogen, and reviews the influence of hormones on the osseointegration.