The effect of four bottom substrates, oyster shell powder(OP), sugarcane bagasse(SB), a mixture of OP and SB(OS) and fresh soil(FS), on the water quality and bacterial and zooplankton density of intensive shrimp(Litop...The effect of four bottom substrates, oyster shell powder(OP), sugarcane bagasse(SB), a mixture of OP and SB(OS) and fresh soil(FS), on the water quality and bacterial and zooplankton density of intensive shrimp(Litopenaeus vannamei) culture tanks without water change and the growth performance of cultured shrimp were compared in this study. At the end of a 110 days culturing trial, the total ammonium-N(TAN) of the water on SB and the nitrite nitrogen(NO2-N) on OS was significantly lower than that on the other substrates(P<0.05), which coincided with the high density of ammonium- and nitrite-oxidizing bacteria in the water on SB and OS, respectively. The concentration of chlorophyll a(Chl a) increased slowly on OP, SB and OS but remained low on FS. The density of total bacteria on OP, SB and OS was one order of magnitude higher than that on FS, and the density of zooplankton on SB and OS was significantly higher than that on FS or OP(P<0.05). The improved water quality and increased density of bacteria and zooplankton on SB and OS may have had a synergistic effect on shrimp culture, improving its growth performance(high survival rate and yield and low feed conversion rate). SB and OS were more effective for improving the growth performance of intensively cultured L. vannamei without water change than OP and FS. To our knowledge, this study presents the first evidence regarding the effect of different bottom substrates on intensive shrimp culture.展开更多
Biofilm-associated microorganisms play crucial roles in terrestrial and aquatic nutrient cycling and in the biodegradation of environmental pollutants. Biofilm formation was determined for a total of 18 bacterial isol...Biofilm-associated microorganisms play crucial roles in terrestrial and aquatic nutrient cycling and in the biodegradation of environmental pollutants. Biofilm formation was determined for a total of 18 bacterial isolates obtained from the biofilms of wastewater treatment systems and of little carpolite in soil. Among these isolates, seven showed strong biofilm-forming capacity. The phylogenetic affiliation of the isolates showing high biofilm formation capacity was determined through 16S rDNA sequencing and the isolates were grouped into 7 bacterial species including Pseudornonas sp., Pseudomonas putida, Aeromonas caviae, Bacillus cereus, Pseudornonas plecoglossicida, Aeromonas hydrophila, and Comamonas testosteroni. The biofilm-forming capacity was closely related with flagella, exopolysaccharide, and extracellular protein. According to the coefficient of determination, the relative importance of the five biological characteristics to biofilm formation was, in order from greatest to least, exopolysaccharide 〉 flagella 〉 N-acyl-homoserine lactones （AHLs） signaling molecules 〉 extracellular protein 〉 swarming motility.展开更多
The study was conducted in water marshes for five major marshes during the months of January, April and September of each region （Hawizeh, Hammer and the central marsh） in southern Iraq. Bacteriological analysis tha...The study was conducted in water marshes for five major marshes during the months of January, April and September of each region （Hawizeh, Hammer and the central marsh） in southern Iraq. Bacteriological analysis that some of the default pathological bacteria, including TC （Total bacterial count）, FCB （faecal coliform bacteria）, MPN （coliform bacteria） and FS （faecal streptococcus） can evidence to indicate of pollution. The results showed that most of the water samples examined pathological contain bacteria which indicates that the water is unfit for human consumption and the waters as basal （more hydrogen than No. 7）. There was a high salinity more than the permissible limits for human consumption and even to irrigate crops, and the same case for dissolve oxygen which exceeded are other limits as drinking water.展开更多
The waxing step plays an important role in production of ripening cheese, the aim of this research is to introduce different concentration of propolis with bee wax to waxing of Gouda cheese, according to a good charac...The waxing step plays an important role in production of ripening cheese, the aim of this research is to introduce different concentration of propolis with bee wax to waxing of Gouda cheese, according to a good characteristic of propolis as antimicrobial. A prospective study carried on samples of Gouda cheese waxed by local bee wax with different percentage of local propolis, then cheese was ripened for three months at l0℃. It was found that addition （10%, 20% and 30%） of propolis effects of total bacterial count, coliform count, molds and yeasts count, 30% of propolis had a higher incidence during the period of Gouda cheese which was ripened for three months, then the 20%, but the 10% of propolis had a few microbial effects, compared with control treatments that had a high count of bacterial, coliform, molds and yeasts. This study shows that difference was observed between the total bacterial count of control treatment （0% propolis） with other treatments （10%, 20% and 30% of propolis） after three months of Gouda cheese ripened as well as difference was observed between the total bacterial count of treatment （30% propolis） and other treatments. However, there was no difference between the treatments 10% and 20%, the study shows that the coliform count decrease by increase of propolis percent compared with the control treatment which had increase of coliform count during ripened period, and it had a high significant difference in the count of coilform to different treatments, but a considerable difference was not observed between coliform count in the second treatment （20% propolis） and that the third treatment （30%） propolis after three months of ripening, the third treatment had a high difference in growth inhibition of molds and yeasts counts compared with the other treatments after three months of ripened Gouda cheese. It could be observed in general that effects of propolis especially the third treatment was a great on the mold and yeasts which is usually growth on the surface of the cheese.展开更多
The occurrence of the spore-forming bacteria in different segments of production lines of Ultra High Temperature （UHT） milk of a commercial plant and its transfer to the final product was studied. The samples were c...The occurrence of the spore-forming bacteria in different segments of production lines of Ultra High Temperature （UHT） milk of a commercial plant and its transfer to the final product was studied. The samples were collected from different segments of production lines from reception to packaging sections, over a period of 75 days at a rate of one sampling a week, from plants in North West of Algeria. The total colony count of aerobic spore-forming bacteria was done using Plate Count Agar （PCA） method. The results showed that there was more than 1 ×10^3 CFU/mL at the level of 50%, 25%, 37.5%, 62.5% and 37.5% of the analyzed samples of milk powder, pasteurized milk, UHT milk （before storage）, UHT milk stored at 55℃ for 7 days and UHT milk stored at 30℃ for 14 days, respectively. The mean total colony count of aerobic spore-forming bacteria was considerably lower in the UHT milk than in the other samples, while the higher proportion of aerobic spore-forming bacteria was noticed to be 32.58% and 30.90% in the UHT milk stored at 55℃ and 30℃, respectively. The results obtained by the classic biochemical identification （Bacillus API 20E）, interpreted by software of calculation for microbial identification reflected the presence of especially Bacillus sphaericus. The other species found were： Bacillus cereus, Bacillus subtilis, Bacillus coagulans, Bacillus licheniformis and Bacillus stearothermophilus. The study reveals that the proportion of aerobic spore-forming bacteria in the final product depends on temperature and storage periods.展开更多
Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be con...Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be considered when water supply to new buildings is planned. The aim of this paper is to review situations that have to be considered in new buildings and give an example on a new water supply contaminated with biofilm producing water bacteria and the precautions introduced to eliminate the contamination. When new buildings are planned it should be considered where to get the water and what is the microbiological quality of the water. If the water is contaminated there will be troubles from the beginning. The material for the pipes should be considered as biofilm which is produced in greater amounts and faster in PEG pipes than in stainless steel pipes. The choice of material depends on the expected lifetime of the building, the dimensions of the pipes, and the choice of forceps, how often the taps are used and thereby the flow in the system. The higher flow the less and slower biofilm formation. It is important to reduce the number of taps to a minimum to ovoid ＂dead ends＂ if they are not or only seldom used. Alternatively all taps could be opened automatically regularly. It is important to establish precautions to ovoid contamination of the water system in the period from when it is established until the building is taken in use. The period can be several months during which the system can act as a ＂dead end＂ if no precautions, such as regularly opening of all taps, are taken. The microbiological quality of the water in the system should be controlled before the building is taken in use. In a new building, where the water supply and the water in the building was not controlled before the building was taken in use, extremely high total and Legionella germ counts were found. The water was disinfected with low concentrations of chloride with very little effect. After disinfection with high concentrations of chloride for few hours and placing a sterile filter at the water entrance both the total and Legionella germ count decreased to an acceptable level.展开更多
The physico-chemical and biological （algal and bacterial） quality of tap water in Tanta City were elucidated. Samples were collected during December 2011, covering all the water plants and the areal extension of the...The physico-chemical and biological （algal and bacterial） quality of tap water in Tanta City were elucidated. Samples were collected during December 2011, covering all the water plants and the areal extension of the pipe line network in Tanta. Total dissolved solids content classifies water origin into surface water, shallow and deep groundwater. Fe, Mn and hardness in some samples of groundwater origin are obviously exceeding the WHO （World Health Organization） limit. Mostly, green algae are found （31 species）, followed by diatoms （19 species）, then blue-green algae （13 species）. CCA （Canonical Corresponding Analysis） indicates that green algae are strongly correlated with pH, NH4, alkalinity, Mn and Si; diatoms with EC （electric conductivity）, turbidity, Zn and Si and blue green algae with EC and alkalinity. 50% of samples of surface origin, 80% of samples of both deep and shallow groundwater origins crossed WHO and Egyptian guideline in their content of mean TCC （Total Coliform Count）. CCA estimates strong correlations of TCC with temperature, NH4 and PO4; E. coli with EC; heterotrophic bacteria with turbidity and NO3; Salmonella sp. with Si and SO4 and Pseudomonas aeruginosa with Mn. Finally, the water plants treatment may be not effective and pipes serve as a reservoir for pathogenic microorganisms.展开更多
基金supported by National Science and Technology Supporting Program of the Twelfth Five-Year Plan of China (2011BAD13B10)the Special Fund for Agro-scientific Research in the Public Interest, China (201103034)
文摘The effect of four bottom substrates, oyster shell powder(OP), sugarcane bagasse(SB), a mixture of OP and SB(OS) and fresh soil(FS), on the water quality and bacterial and zooplankton density of intensive shrimp(Litopenaeus vannamei) culture tanks without water change and the growth performance of cultured shrimp were compared in this study. At the end of a 110 days culturing trial, the total ammonium-N(TAN) of the water on SB and the nitrite nitrogen(NO2-N) on OS was significantly lower than that on the other substrates(P<0.05), which coincided with the high density of ammonium- and nitrite-oxidizing bacteria in the water on SB and OS, respectively. The concentration of chlorophyll a(Chl a) increased slowly on OP, SB and OS but remained low on FS. The density of total bacteria on OP, SB and OS was one order of magnitude higher than that on FS, and the density of zooplankton on SB and OS was significantly higher than that on FS or OP(P<0.05). The improved water quality and increased density of bacteria and zooplankton on SB and OS may have had a synergistic effect on shrimp culture, improving its growth performance(high survival rate and yield and low feed conversion rate). SB and OS were more effective for improving the growth performance of intensively cultured L. vannamei without water change than OP and FS. To our knowledge, this study presents the first evidence regarding the effect of different bottom substrates on intensive shrimp culture.
基金supported by the National Natural Science Foundation of China (No.30600016)the Environment Protection Department of Jiangsu Province,China (No.2004007)
文摘Biofilm-associated microorganisms play crucial roles in terrestrial and aquatic nutrient cycling and in the biodegradation of environmental pollutants. Biofilm formation was determined for a total of 18 bacterial isolates obtained from the biofilms of wastewater treatment systems and of little carpolite in soil. Among these isolates, seven showed strong biofilm-forming capacity. The phylogenetic affiliation of the isolates showing high biofilm formation capacity was determined through 16S rDNA sequencing and the isolates were grouped into 7 bacterial species including Pseudornonas sp., Pseudomonas putida, Aeromonas caviae, Bacillus cereus, Pseudornonas plecoglossicida, Aeromonas hydrophila, and Comamonas testosteroni. The biofilm-forming capacity was closely related with flagella, exopolysaccharide, and extracellular protein. According to the coefficient of determination, the relative importance of the five biological characteristics to biofilm formation was, in order from greatest to least, exopolysaccharide 〉 flagella 〉 N-acyl-homoserine lactones （AHLs） signaling molecules 〉 extracellular protein 〉 swarming motility.
文摘The study was conducted in water marshes for five major marshes during the months of January, April and September of each region （Hawizeh, Hammer and the central marsh） in southern Iraq. Bacteriological analysis that some of the default pathological bacteria, including TC （Total bacterial count）, FCB （faecal coliform bacteria）, MPN （coliform bacteria） and FS （faecal streptococcus） can evidence to indicate of pollution. The results showed that most of the water samples examined pathological contain bacteria which indicates that the water is unfit for human consumption and the waters as basal （more hydrogen than No. 7）. There was a high salinity more than the permissible limits for human consumption and even to irrigate crops, and the same case for dissolve oxygen which exceeded are other limits as drinking water.
文摘The waxing step plays an important role in production of ripening cheese, the aim of this research is to introduce different concentration of propolis with bee wax to waxing of Gouda cheese, according to a good characteristic of propolis as antimicrobial. A prospective study carried on samples of Gouda cheese waxed by local bee wax with different percentage of local propolis, then cheese was ripened for three months at l0℃. It was found that addition （10%, 20% and 30%） of propolis effects of total bacterial count, coliform count, molds and yeasts count, 30% of propolis had a higher incidence during the period of Gouda cheese which was ripened for three months, then the 20%, but the 10% of propolis had a few microbial effects, compared with control treatments that had a high count of bacterial, coliform, molds and yeasts. This study shows that difference was observed between the total bacterial count of control treatment （0% propolis） with other treatments （10%, 20% and 30% of propolis） after three months of Gouda cheese ripened as well as difference was observed between the total bacterial count of treatment （30% propolis） and other treatments. However, there was no difference between the treatments 10% and 20%, the study shows that the coliform count decrease by increase of propolis percent compared with the control treatment which had increase of coliform count during ripened period, and it had a high significant difference in the count of coilform to different treatments, but a considerable difference was not observed between coliform count in the second treatment （20% propolis） and that the third treatment （30%） propolis after three months of ripening, the third treatment had a high difference in growth inhibition of molds and yeasts counts compared with the other treatments after three months of ripened Gouda cheese. It could be observed in general that effects of propolis especially the third treatment was a great on the mold and yeasts which is usually growth on the surface of the cheese.
文摘The occurrence of the spore-forming bacteria in different segments of production lines of Ultra High Temperature （UHT） milk of a commercial plant and its transfer to the final product was studied. The samples were collected from different segments of production lines from reception to packaging sections, over a period of 75 days at a rate of one sampling a week, from plants in North West of Algeria. The total colony count of aerobic spore-forming bacteria was done using Plate Count Agar （PCA） method. The results showed that there was more than 1 ×10^3 CFU/mL at the level of 50%, 25%, 37.5%, 62.5% and 37.5% of the analyzed samples of milk powder, pasteurized milk, UHT milk （before storage）, UHT milk stored at 55℃ for 7 days and UHT milk stored at 30℃ for 14 days, respectively. The mean total colony count of aerobic spore-forming bacteria was considerably lower in the UHT milk than in the other samples, while the higher proportion of aerobic spore-forming bacteria was noticed to be 32.58% and 30.90% in the UHT milk stored at 55℃ and 30℃, respectively. The results obtained by the classic biochemical identification （Bacillus API 20E）, interpreted by software of calculation for microbial identification reflected the presence of especially Bacillus sphaericus. The other species found were： Bacillus cereus, Bacillus subtilis, Bacillus coagulans, Bacillus licheniformis and Bacillus stearothermophilus. The study reveals that the proportion of aerobic spore-forming bacteria in the final product depends on temperature and storage periods.
文摘Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be considered when water supply to new buildings is planned. The aim of this paper is to review situations that have to be considered in new buildings and give an example on a new water supply contaminated with biofilm producing water bacteria and the precautions introduced to eliminate the contamination. When new buildings are planned it should be considered where to get the water and what is the microbiological quality of the water. If the water is contaminated there will be troubles from the beginning. The material for the pipes should be considered as biofilm which is produced in greater amounts and faster in PEG pipes than in stainless steel pipes. The choice of material depends on the expected lifetime of the building, the dimensions of the pipes, and the choice of forceps, how often the taps are used and thereby the flow in the system. The higher flow the less and slower biofilm formation. It is important to reduce the number of taps to a minimum to ovoid ＂dead ends＂ if they are not or only seldom used. Alternatively all taps could be opened automatically regularly. It is important to establish precautions to ovoid contamination of the water system in the period from when it is established until the building is taken in use. The period can be several months during which the system can act as a ＂dead end＂ if no precautions, such as regularly opening of all taps, are taken. The microbiological quality of the water in the system should be controlled before the building is taken in use. In a new building, where the water supply and the water in the building was not controlled before the building was taken in use, extremely high total and Legionella germ counts were found. The water was disinfected with low concentrations of chloride with very little effect. After disinfection with high concentrations of chloride for few hours and placing a sterile filter at the water entrance both the total and Legionella germ count decreased to an acceptable level.
文摘The physico-chemical and biological （algal and bacterial） quality of tap water in Tanta City were elucidated. Samples were collected during December 2011, covering all the water plants and the areal extension of the pipe line network in Tanta. Total dissolved solids content classifies water origin into surface water, shallow and deep groundwater. Fe, Mn and hardness in some samples of groundwater origin are obviously exceeding the WHO （World Health Organization） limit. Mostly, green algae are found （31 species）, followed by diatoms （19 species）, then blue-green algae （13 species）. CCA （Canonical Corresponding Analysis） indicates that green algae are strongly correlated with pH, NH4, alkalinity, Mn and Si; diatoms with EC （electric conductivity）, turbidity, Zn and Si and blue green algae with EC and alkalinity. 50% of samples of surface origin, 80% of samples of both deep and shallow groundwater origins crossed WHO and Egyptian guideline in their content of mean TCC （Total Coliform Count）. CCA estimates strong correlations of TCC with temperature, NH4 and PO4; E. coli with EC; heterotrophic bacteria with turbidity and NO3; Salmonella sp. with Si and SO4 and Pseudomonas aeruginosa with Mn. Finally, the water plants treatment may be not effective and pipes serve as a reservoir for pathogenic microorganisms.
