Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obta...Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obtain rumen protozoa and bacteria. Two groups were designed as follows： One group was the whole bacteria which were labeled using fluorescence through removing free bacteria from rumen fluid （WFLB）; the other group was the bacteria which were labeled using fluorescence without removing free bacteria from rumen fluid （FLB）. The result indicated that the bacterial predation rates of rumen protozoa was 398.4 cells/（cell h） for the group WFLB, 230.4 cells/（cell h） for the group FLB, when the corresponding values expressed as bacteria-N, they were 2.15 pg N/（cell h） for the group WFLB, and 1.24 pg N/（cell h） for the group FLB, respectively. Extrapolating the assimilation quantity of nitrogen by ciliates on bacteria of Xuhuai goat, there were 103.2 mg N/（d capita） for the group WFLB, and 59.5 mg N/（d capita） for the group FLB, respectively. It was estimated that protein losses due to microbial recycling were 0.645 g pro/（d capita） for the group WFLB and 0.372 g pro/（d capita） for the group FLB, respectively. In addition, the fluorescence-labeled technique would be a potential assay for the determination of bacterial predation rate by rumen protozoa.展开更多
Two cruises were conducted in January and July 1986 in the Changjiang (Yangtse River) Estuary and its adjacent East China Sea (30°45′ -32°00′N,121°00′-124°00′E). Direct epifluorescence counts o...Two cruises were conducted in January and July 1986 in the Changjiang (Yangtse River) Estuary and its adjacent East China Sea (30°45′ -32°00′N,121°00′-124°00′E). Direct epifluorescence counts of planktonic bacteria and determinations of ATP concentrations were made. Subsamples were taken for measurement of oxygen consumption rates and chlorophyll concentrations.Bacteria and ATP concentrations were higher in summer than in winter, highest in the river and the river mouth, and gradually lower offshore. The bacteria number was correlated positively with suspended matter, nitrates and oxygen consumption rates, and negatively with salinity.In winter bacteria were the main contributors of ATP and the main consumers of dissolved oxygen in the whole studied area. In summer two maxima of ATP were found along the salinity gradient. The first one which coincided with the peak of turbidity near the river mouth was attributed to bacte -ria, and the second which occurred in the waters with a salinity range展开更多
Fecal indicator bacteria, such as total coliforms and E. coli, are a challenge to control in urban and rural stormwater runoff. To assess the challenges of improving bacterial water quality standards in surface waters...Fecal indicator bacteria, such as total coliforms and E. coli, are a challenge to control in urban and rural stormwater runoff. To assess the challenges of improving bacterial water quality standards in surface waters, microcosm experiments were conducted to assess how decay rates of total coliforms and E. coli are affected by sediments and associated organic matter. Samples were collected at a lake embayment to create laboratory microcosms consisting of different combinations of unsterilized and sterilized water and sediment. Calculated first-order decay rate constants ranged from 0.021 to 0.047 h-1 for total coliforms and 0.017 and 0.037 h-1 for E. coli, depending on how each microcosm was prepared. It is evident that sediment in contact with the water column decreases bacteria decay rate, showing that care should be taken when designing stormwater treatment measures. In addition, high organic carbon content in the sediment temporarily increased bacteria concentrations in the water column. The results demonstrate that stormwater treatment measures, such as extended detention basins and constructed wetlands, must hold water for several days to allow for reduction of bacterial concentrations to acceptable levels. In addition, to troubleshoot detention basins and constructed wetlands for causes of high effluent bacterial concentrations, analyses of sediment, organic carbon, and water column depth should be conducted.展开更多
目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性...目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性杆菌、阳性球菌对抗菌药物产生的耐药率(%)与抗菌药物用药频度(Frequency of defined daily doses,DDDs)的相关性。结果:我院2018年至2021年抗菌药物DDDs较高的抗菌药物依次为美洛西林、头孢他啶、哌拉西林他唑巴坦,检出率较高的病原菌分别为大肠埃希氏菌、肺炎克雷伯菌、金黄色葡萄球菌等。大肠埃希菌产生的耐药率与哌拉西林他唑巴坦、头孢呋辛钠DDDs均有相关性(r=-0.107、0.432);肺炎克雷伯菌产生的耐药率与哌拉西林他唑巴坦、左氧氟沙星氯化钠、头孢呋辛钠DDDs呈正相关(r=0.410、0.720、0.420);铜绿假单胞菌与哌拉西林他唑巴坦、头孢哌酮舒巴坦钠DDDs呈正相关(r=0.716、0.933);金黄色葡萄球菌的耐药率与左氧氟沙星DDDs呈正相关(r=0.661);肺炎链球菌产生的耐药率与左氧氟沙星、头孢呋辛钠DDDs均存在正相关关系(r=0.416和0.482)。结论:抗菌药物的DDDs与常见细菌产生的耐药性具有一定的相关性,我院应严格控制抗菌药物的DDDs,根据感染性病种及药敏试验结果选择适当的抗菌药,加强常见病原菌的耐药监测。展开更多
基金carried out under the financial support from the National Natural Science Foundation of China(30571344).
文摘Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obtain rumen protozoa and bacteria. Two groups were designed as follows： One group was the whole bacteria which were labeled using fluorescence through removing free bacteria from rumen fluid （WFLB）; the other group was the bacteria which were labeled using fluorescence without removing free bacteria from rumen fluid （FLB）. The result indicated that the bacterial predation rates of rumen protozoa was 398.4 cells/（cell h） for the group WFLB, 230.4 cells/（cell h） for the group FLB, when the corresponding values expressed as bacteria-N, they were 2.15 pg N/（cell h） for the group WFLB, and 1.24 pg N/（cell h） for the group FLB, respectively. Extrapolating the assimilation quantity of nitrogen by ciliates on bacteria of Xuhuai goat, there were 103.2 mg N/（d capita） for the group WFLB, and 59.5 mg N/（d capita） for the group FLB, respectively. It was estimated that protein losses due to microbial recycling were 0.645 g pro/（d capita） for the group WFLB and 0.372 g pro/（d capita） for the group FLB, respectively. In addition, the fluorescence-labeled technique would be a potential assay for the determination of bacterial predation rate by rumen protozoa.
文摘Two cruises were conducted in January and July 1986 in the Changjiang (Yangtse River) Estuary and its adjacent East China Sea (30°45′ -32°00′N,121°00′-124°00′E). Direct epifluorescence counts of planktonic bacteria and determinations of ATP concentrations were made. Subsamples were taken for measurement of oxygen consumption rates and chlorophyll concentrations.Bacteria and ATP concentrations were higher in summer than in winter, highest in the river and the river mouth, and gradually lower offshore. The bacteria number was correlated positively with suspended matter, nitrates and oxygen consumption rates, and negatively with salinity.In winter bacteria were the main contributors of ATP and the main consumers of dissolved oxygen in the whole studied area. In summer two maxima of ATP were found along the salinity gradient. The first one which coincided with the peak of turbidity near the river mouth was attributed to bacte -ria, and the second which occurred in the waters with a salinity range
文摘Fecal indicator bacteria, such as total coliforms and E. coli, are a challenge to control in urban and rural stormwater runoff. To assess the challenges of improving bacterial water quality standards in surface waters, microcosm experiments were conducted to assess how decay rates of total coliforms and E. coli are affected by sediments and associated organic matter. Samples were collected at a lake embayment to create laboratory microcosms consisting of different combinations of unsterilized and sterilized water and sediment. Calculated first-order decay rate constants ranged from 0.021 to 0.047 h-1 for total coliforms and 0.017 and 0.037 h-1 for E. coli, depending on how each microcosm was prepared. It is evident that sediment in contact with the water column decreases bacteria decay rate, showing that care should be taken when designing stormwater treatment measures. In addition, high organic carbon content in the sediment temporarily increased bacteria concentrations in the water column. The results demonstrate that stormwater treatment measures, such as extended detention basins and constructed wetlands, must hold water for several days to allow for reduction of bacterial concentrations to acceptable levels. In addition, to troubleshoot detention basins and constructed wetlands for causes of high effluent bacterial concentrations, analyses of sediment, organic carbon, and water column depth should be conducted.
文摘目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性杆菌、阳性球菌对抗菌药物产生的耐药率(%)与抗菌药物用药频度(Frequency of defined daily doses,DDDs)的相关性。结果:我院2018年至2021年抗菌药物DDDs较高的抗菌药物依次为美洛西林、头孢他啶、哌拉西林他唑巴坦,检出率较高的病原菌分别为大肠埃希氏菌、肺炎克雷伯菌、金黄色葡萄球菌等。大肠埃希菌产生的耐药率与哌拉西林他唑巴坦、头孢呋辛钠DDDs均有相关性(r=-0.107、0.432);肺炎克雷伯菌产生的耐药率与哌拉西林他唑巴坦、左氧氟沙星氯化钠、头孢呋辛钠DDDs呈正相关(r=0.410、0.720、0.420);铜绿假单胞菌与哌拉西林他唑巴坦、头孢哌酮舒巴坦钠DDDs呈正相关(r=0.716、0.933);金黄色葡萄球菌的耐药率与左氧氟沙星DDDs呈正相关(r=0.661);肺炎链球菌产生的耐药率与左氧氟沙星、头孢呋辛钠DDDs均存在正相关关系(r=0.416和0.482)。结论:抗菌药物的DDDs与常见细菌产生的耐药性具有一定的相关性,我院应严格控制抗菌药物的DDDs,根据感染性病种及药敏试验结果选择适当的抗菌药,加强常见病原菌的耐药监测。
