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Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was found initially in Wuhan, China in early December 2019. The pandemic has spread to 216 countries and regions, infecting more than 23310 000 people and causing over 800 000 deaths globally by Aug. 24, 2020, according to World Health Organization (https://www.who.int/emergencies/diseases/ novel-coronavirus-2019). Fever, cough, and dyspnea are the three common symptoms of the condition, whereas the conventional transmission route for SARS-CoV-2 is through droplets entering the respiratory tract. To date, infection control measures for COVID-19 have been focusing on the involvement of the respiratory system. However, ignoring potential faecal transmission and the gastrointestinal involvement of SARS-CoV-2 may result in mistakes in attempts to control the pandemic.
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Humanos , Betacoronavirus/aislamiento & purificación , COVID-19 , China/epidemiología , Infecciones por Coronavirus/virología , Microbiología Ambiental , Heces/virología , Enfermedades Gastrointestinales/virología , Modelos Biológicos , Pandemias , Neumonía Viral/virología , ARN Viral/genética , SARS-CoV-2 , Esparcimiento de VirusRESUMEN
Pg.The adherence activity of periodontal pathogens to HA was enhanced by Ss and Av.When cultivated with Sm,the adherence activity of Pg was reduced.Periodontal pathogens had no effect on the adherence activity of Sm and Av,and Ss excepted. Conclusion The adherence activity of periodontal pathogens is lower than that of cariogenic bacteria.Periodontal pathogens can utilize early-attached bacteria to become those predominant bacteria in periodontal ecosystem.
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<p><b>OBJECTIVE</b>To study dynamic relation between periodontal pathogens and cariogenic bacteria under analogous oral environment.</p><p><b>METHODS</b>Eight periodontopathic and cariogenic bacteria of Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Provotella intermedium (Pi), Streptococcus mutans (Sm), Streptococcus sanguis (Ss), Actinomyces viscosus (Av) and Lactobacillus acidophilus (La) were used. These eight strains were cultured in modified chemostat under analogous oral environment which contained 600 ml modified BM medium supplemented with 2.5 g/L porcine gastric mucin, respectively. After 1, 24, 48 and 96 h, optical sectioning of plaque biofilms on removable and replaceable hydroxyapatite disks was analyzed by the combination of live bacterial Gram fluorescence staining and confocal laser scanning microscopy. Biofilm thickness and reconstruction of the three-dimensional architecture of plaque biofilms were made.</p><p><b>RESULTS</b>Biofilm thickness increased significantly with time (P < 0.001). Biofilms of Aa were thinner than those of Ss and eight-specie biofilms were thicker than those formed by Ss and Aa per time point. Three-dimensional images showed periodontal pathogens mainly occurred in cariogenic bacterial complex or on the biofilm surface.</p><p><b>CONCLUSIONS</b>Gram-positive cariogenic species initially predominated in artificial plaque, followed by the increasing proportions of Gram-negative periodontal pathogens. The relation between microecological balance among bacteria and diseases is worthy of further studies.</p>
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Humanos , Bacterias , Biopelículas , Caries Dental , Microbiología , Ecología , Microscopía Confocal , Enfermedades Periodontales , MicrobiologíaRESUMEN
<p><b>OBJECTIVES</b>To study the inhibitory effect of KF-950 on human acrosin and sperm acrosome.</p><p><b>METHODS</b>Human acrosin was extracted and purified with 2% acetic acid, and its residual activity was evaluated by BAEE/ADH assay after treated with different concentrations of KF-950. ABC assay was used to observe the effect of KF-950 on human acrosome with Biotin-PSA as a probe.</p><p><b>RESULTS</b>1. The activity of normal sperm acrosin was (37.65 +/- 4.47) U/L. 2. The residual activity was inversely related to the concentration of KF-950 (r = -0.998), and had a dose-response curve. The result could be described by Y = 7.57-1.895X. 3. With increase of KF-950 concentration and prolongation of action time, the staining rate of acrosome obviously dropped (P < 0.01).</p><p><b>CONCLUSIONS</b>KF-950 directly inhibits acrosin activity and assumely injures sperm acrosome. It might be a new kind of highly effective inhibitor.</p>