We compared chemical and biological properties of soils in organically and conventionally fertilized apple orchards in Nagano Prefecture (one of the major apple producing regions in Japan). Five apple orchards with di...We compared chemical and biological properties of soils in organically and conventionally fertilized apple orchards in Nagano Prefecture (one of the major apple producing regions in Japan). Five apple orchards with different fertilizer management systems were used for this study. The total carbon and total nitrogen contents were higher in the organically fertilized orchard, while the total phosphorus and total potassium were at similar levels in both organically and conventionally fertilized orchards. The bacterial biomass did not differ between the two orchards, but the N circulation activity was clearly higher in the organically fertilized orchard from April to December. Total carbon from 50,000 to 60,000 mg/kg, total nitrogen at about 3000 to 4000 mg/kg, and a C/N ratio of 15 - 20 were suggested to be suitable conditions for a high level of apple production under an organic fertilizer management system.展开更多
Popcorn is a very social food, often shared with others and offered at many major sporting events, concerts, movies, and fairs. However, sharing may not be safe since microorganisms found on hands may be transferred o...Popcorn is a very social food, often shared with others and offered at many major sporting events, concerts, movies, and fairs. However, sharing may not be safe since microorganisms found on hands may be transferred onto the shared popcorn. This study was conducted to determine if bacteria are transferred from hands to popcorn during handling. Over 30 samplings revealed that bacterial transfer to popcorn from hands was very low;however transfer did occur with large variation between subjects. Since hands and surfaces can carry bacteria in situations where food is being shared, transferring bacteria from one person to another person is always a risk.展开更多
Traditionally,optical microscopy is used to visualize the morphological features of pathogenic bacteria,of which the features are further used for the detection and ident ification of the bacteria.However,due to the r...Traditionally,optical microscopy is used to visualize the morphological features of pathogenic bacteria,of which the features are further used for the detection and ident ification of the bacteria.However,due to the resolution limitation of conventional optical microscopy as well as the lack of standard pattern library for bacteria identification,the ffectiveness of this optical microscopy-based method is limited.Here,we reported a pilot study on a combined use of Structured Illumination Microscopy(SIM)with machine learning for rapid bacteria identification.After applying machine learning to the SIM image datasets from three model bacteria(including Escherichia coli,Mycobacterium smegmatis,and Pseudomonas aeruginosa),we obtained a classifcation accuracy of up to 98%.This study points out a promising possibility for rapid bacterial identification by morphological features.展开更多
采用变性梯度凝胶电泳（DGGE）技术对内蒙古河套灌区三种不同盐碱程度土壤（盐土,强度盐化土,轻度盐化土）不同深度（0~20cm和20~30cm）土壤细菌16S r DNA V3~V6可变区扩增片段进行分析,并对土壤理化性质进行了测定.结果表明：细菌群落...采用变性梯度凝胶电泳（DGGE）技术对内蒙古河套灌区三种不同盐碱程度土壤（盐土,强度盐化土,轻度盐化土）不同深度（0~20cm和20~30cm）土壤细菌16S r DNA V3~V6可变区扩增片段进行分析,并对土壤理化性质进行了测定.结果表明：细菌群落多样性随土壤盐碱化程度的加深而减少（轻度盐化土〉强度盐化土〉盐土）,随土壤深度的增加而降低（细菌群落多样性0~20cm土层大于20~30cm土层）.细菌Shannon-Wiener指数在轻度盐化土中最大为3.36,在强度盐化土和盐土分别为3.05和2.49.不同盐碱程度土壤以细菌相似系数聚类,分为0~20cm层与20~30cm层两大族群,土壤细菌群落Shannon-Wiener指数在0~20cm层中（盐土为3.04,强度盐化土为3.29,轻度盐化土为3.36）均大于在20~30cm层（盐土为2.49,强度盐化土为3.05,轻度盐化土为3.14）.相关性分析和典范对应分析表明,土壤w（EC）、p H值、w（SOC）、w（TP）是土壤细菌群落结构多样性的显著影响因素,不同盐碱程度土壤中细菌群落的Shannon-Wiener指数与土壤w（EC）（r=-0.542,P〈0.05）、p H（r=-0.526,P〈0.05）呈显著负相关,与土壤w（SOC）（r=0.700,P〈0.01）和w（TP）（r=0.805,P〈0.01）呈极显著正相关.w（EC）和p H对盐碱土壤细菌群落结构的影响力最大.回收DGGE图谱中20个优势条带进行测序分析,结果显示,变形菌纲（α-变形菌纲、β-变形菌纲、γ-变形菌纲和δ-变形菌纲）是盐碱土壤的主要类群.展开更多
文摘We compared chemical and biological properties of soils in organically and conventionally fertilized apple orchards in Nagano Prefecture (one of the major apple producing regions in Japan). Five apple orchards with different fertilizer management systems were used for this study. The total carbon and total nitrogen contents were higher in the organically fertilized orchard, while the total phosphorus and total potassium were at similar levels in both organically and conventionally fertilized orchards. The bacterial biomass did not differ between the two orchards, but the N circulation activity was clearly higher in the organically fertilized orchard from April to December. Total carbon from 50,000 to 60,000 mg/kg, total nitrogen at about 3000 to 4000 mg/kg, and a C/N ratio of 15 - 20 were suggested to be suitable conditions for a high level of apple production under an organic fertilizer management system.
文摘Popcorn is a very social food, often shared with others and offered at many major sporting events, concerts, movies, and fairs. However, sharing may not be safe since microorganisms found on hands may be transferred onto the shared popcorn. This study was conducted to determine if bacteria are transferred from hands to popcorn during handling. Over 30 samplings revealed that bacterial transfer to popcorn from hands was very low;however transfer did occur with large variation between subjects. Since hands and surfaces can carry bacteria in situations where food is being shared, transferring bacteria from one person to another person is always a risk.
基金supported by the National Key Research and Development Program of China(Grant No.2017-YFD0500303)the National Natural Science Foundation of China(Grant Nos.31371106,91640105)+1 种基金the China Agriculture Research System(No.CARS-36)the Huazhong Agricultural University Scienti¯c and Technological Self-innovation Foundation(Program No.52204-13002).
文摘Traditionally,optical microscopy is used to visualize the morphological features of pathogenic bacteria,of which the features are further used for the detection and ident ification of the bacteria.However,due to the resolution limitation of conventional optical microscopy as well as the lack of standard pattern library for bacteria identification,the ffectiveness of this optical microscopy-based method is limited.Here,we reported a pilot study on a combined use of Structured Illumination Microscopy(SIM)with machine learning for rapid bacteria identification.After applying machine learning to the SIM image datasets from three model bacteria(including Escherichia coli,Mycobacterium smegmatis,and Pseudomonas aeruginosa),we obtained a classifcation accuracy of up to 98%.This study points out a promising possibility for rapid bacterial identification by morphological features.
文摘采用变性梯度凝胶电泳（DGGE）技术对内蒙古河套灌区三种不同盐碱程度土壤（盐土,强度盐化土,轻度盐化土）不同深度（0~20cm和20~30cm）土壤细菌16S r DNA V3~V6可变区扩增片段进行分析,并对土壤理化性质进行了测定.结果表明：细菌群落多样性随土壤盐碱化程度的加深而减少（轻度盐化土〉强度盐化土〉盐土）,随土壤深度的增加而降低（细菌群落多样性0~20cm土层大于20~30cm土层）.细菌Shannon-Wiener指数在轻度盐化土中最大为3.36,在强度盐化土和盐土分别为3.05和2.49.不同盐碱程度土壤以细菌相似系数聚类,分为0~20cm层与20~30cm层两大族群,土壤细菌群落Shannon-Wiener指数在0~20cm层中（盐土为3.04,强度盐化土为3.29,轻度盐化土为3.36）均大于在20~30cm层（盐土为2.49,强度盐化土为3.05,轻度盐化土为3.14）.相关性分析和典范对应分析表明,土壤w（EC）、p H值、w（SOC）、w（TP）是土壤细菌群落结构多样性的显著影响因素,不同盐碱程度土壤中细菌群落的Shannon-Wiener指数与土壤w（EC）（r=-0.542,P〈0.05）、p H（r=-0.526,P〈0.05）呈显著负相关,与土壤w（SOC）（r=0.700,P〈0.01）和w（TP）（r=0.805,P〈0.01）呈极显著正相关.w（EC）和p H对盐碱土壤细菌群落结构的影响力最大.回收DGGE图谱中20个优势条带进行测序分析,结果显示,变形菌纲（α-变形菌纲、β-变形菌纲、γ-变形菌纲和δ-变形菌纲）是盐碱土壤的主要类群.
文摘粪肠球菌是难治性根尖周炎(refractory apical periodontitis,RAP)的主要致病菌,该细菌可耐受严苛环境,引发根尖周免疫炎症反应,造成根管内外持续性感染。粪肠球菌黏附于根管牙本质壁形成生物膜,其耐药和抗冲刷能力显著增强,是介导其致病的关键因素。粪肠球菌与牙本质的黏附包括非特异性和特异性黏附,后者由黏附相关毒力因子介导,主要包括肠球菌胶原结合蛋白(adhesin of collagen from enterococci,Ace)、表面蛋白(extracellular surface protein,Esp)、明胶酶(gelatinase,GelE)和丝氨酸蛋白酶(serine prtease,SprE)、菌毛以及聚集物质,且受到多个双组份系统调控。Fsr双组份系统在群体密度增加时可以促进gelE及sprE的表达,GelE进一步减少表面肠球菌胶原结合蛋白Ace,而GrvRS双组份系统则在响应血清环境时直接下调ace的表达。CroRS双组份系统及WalRK双组份系统也可能分别促进和抑制包括ace及gelE在内的多种毒力因子的表达,进而影响粪肠球菌的黏附性。此外,根管机械/化学预备、根管内环境因素等均可对粪肠球菌牙本质黏附产生影响。根管治疗中避免粪肠球菌的引入和使用干扰黏附的药物可以有效预防粪肠球菌的黏附,而多种活化荡洗方法也可以有效增加根管内粪肠球菌的清除率。针对粪肠球菌牙本质黏附关键因子与调控因素为靶点设计合理药物,有望为根管感染控制提供新的思路与手段。本文就粪肠球菌与牙本质的黏附性及其影响因素进行综述。
