This study evaluated transfer of maternal lysozyme and immunoglobulin (IgM) against Lactococcus garviea, the causative agent of lactococcosis to eggs and larvae in rainbow trout. Changes in circulating lysozyme and Ig...This study evaluated transfer of maternal lysozyme and immunoglobulin (IgM) against Lactococcus garviea, the causative agent of lactococcosis to eggs and larvae in rainbow trout. Changes in circulating lysozyme and IgM during development of eggs and larvae were measured by a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus and enzyme-linked immunosorbent assay (ELISA) respectively. For doing this, twelve broodstocks were injected weekly with 2.5 mg·kg-1 letrozole (an endocrine disrupter component) two months before spawning season and vaccinated intraperitoneally (i.p) with a bacterin (inactivated L. garviae) one month before spawning. Twelve broodstocks for vaccination and twelve female rainbow trouts as control group were also immiunised (i.p) with the bacterin and injected (i.p) with PBS respectively. Results showed that at day 8 after hatching, lysozyme and IgM levels during pre-larval stages decreased gradually, as yolks were absorbed. Lysozyme and IgM levels were significantly higher in the letrozole injected immiunised parents 30 days after immunisation as well as their larvae compared to the control group (p L. garviae) (one month before spawning) in maternal transfer of lysozyme and IgM levels to eggs and larvae.展开更多
This study evaluated efficacy of maternal and larval immunisation against Lactococcus garviae infection and on the lysozyme and immunoglobulin (IgM) levels in rainbow trout Oncorhynchus mykiss (Walaum). Forty-eight-da...This study evaluated efficacy of maternal and larval immunisation against Lactococcus garviae infection and on the lysozyme and immunoglobulin (IgM) levels in rainbow trout Oncorhynchus mykiss (Walaum). Forty-eight-day-old larvae (mean weight 96 mg) originating from injected weekly with letrozole and immunised, only immunised and non-immunised parents were experimentally infected with the L. garvieae, and the mortality rate was recorded daily. Larvae were vaccinated by immersion at 58 days post hatch with live L. garvieae (109 cells/mL) for 15 min. Every third day post larvae vaccination, two larvae from each group were collected for analysis lysozyme (by a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus) and IgM (by enzyme-linked immunosorbent assay (ELISA)) parameters. Vaccinated and control larvae were tested for protection against L. garvieae 30 days post larvae immunization when the larvae were 88 days old. Larvae were challenged by bath exposure with live L. garvieae (109 cells/mL) for 2 min and monitored for mortality for at least 10 days following challenge. The challenge experiment with L. garvieae showed a significant reduction in larvae from immunised (54.44% ± 0.64%) and injected weekly with letrozole and immunised fish (52.96% ± 0.97%) compared to larvae from control fish (62.96% ± 2.22%). Vaccinated larvae originated from injected weekly with letrozole and immunised parents showed significantly higher lysozyme activity compared to other fish groups. Vaccinated larvae showed significantly less mortality compared to controls. The relative percent survival (RPS) values of larvae from only immunised, injected weekly with letrozole and immunised and non-immunised parents vaccinated with L. garvieae were 67.36% ± 0.9%, 68.05% ± 0.66% and 48.27% ± 2.79% respectively. The results indicate that the effect of maternal immunization rainbow trout against L. garvieae infection by eliciting the immune responses as indicated by an increase in the IgM level and lysozyme activity.展开更多
This study was carried out to investigate the effect of different concentrations of garlic (Allium sativum L.) extract in fish diet on survival rate, digestive enzymes and some biochemical parameters of Mugil cephalus...This study was carried out to investigate the effect of different concentrations of garlic (Allium sativum L.) extract in fish diet on survival rate, digestive enzymes and some biochemical parameters of Mugil cephalus larvae. Three hundred and sixty fish with mean weight 0.45 g were randomly divided into equal four groups;each one contained 3 replicates. Fish was fed with diets containing 0% (control), 0.5%, 1% and 3% concentrations of garlic extract (GE) in diet. 30 days after feeding, survival rate, different biochemical (larvae extract total protein, albumin, globulin, glucose, cholesterol and triglyceride) parameters and digestive enzyme activity (lipase, protease and amylase) were evaluated. There was a significant increase in survival rate of all groups fed with GE as compared to the control diet (P < 0.05). The administration of A. sativum in all levels significantly decreased (P < 0.05) the content of cholesterol, triglyceride and glucose in larvae extract. Also total protein, albumin and globulin levels had significantly increased in all groups fed GE (P < 0.05). The highest total protein (2.13 ± 0.12 g/dL), albumin (0.37 ± 0 g/dL), globulin (1.76 ± 0.12 g/dL), amylase (9.25 ± 0.14 U/mg protein), protease (4.20 ± 0.08 U/mg protein) and lipase (2.62 ± 0.14 U/mg protein) and the lowest serum triglyceride (22.78 ± 0.20 mg/dL), glucose (8.76 ± 0.09 mg/dL), cholesterol (3.69 ± 0.07 mg/dL) levels were observed in fish fed 3% GE in diet. Garlic inclusion in fish diet at 3% concentration is therefore beneficial for use in aquaculture to improve the general health and digestive enzyme activity of M. cephalus larvae.展开更多
A chitinase was identified in extracellular products of a virulent?Aeromonas hydrophila?isolated from diseased channel catfish (Ictalurus punctatus). Recombinant chitinase (rChi-Ah) was produced in?Escherichia coli. P...A chitinase was identified in extracellular products of a virulent?Aeromonas hydrophila?isolated from diseased channel catfish (Ictalurus punctatus). Recombinant chitinase (rChi-Ah) was produced in?Escherichia coli. Purified rChi-Ah had optimal activity at temperature of 42℃?and pH 6.5. The affinity (Km) for chitosan was 4.18 mg·ml-1?with?Vmax?of 202.5 mg·min-1·mg-1. With colloidal chitin as substrate, rChi-Ah generated N,N’-diacetyl-glucosamine predominantly. Conversion of chitosan (≥75% deacetylated) by rChi-Ah revealed five major products: 2 to 4 units of glucosamine, all of which had at least one acetyl group. It was determined that N-acetylated glucosamine was the recognition and cleavage site of rChi-Ah;the minimal and maximal cleavages were two and four glucosamine units, respectively. Functional analysis of rChi-Ah suggests that?A. hydrophilachitinase is a bioactive chitinolytic enzyme, which may benefit the pathogen for survival and/or infection.展开更多
Despite being known as resistant proteins, peanut allergens (Ara h 1 and Ara h 2) can be digested and cause allergic reactions. Making the allergens more resistant to digestion may aid in non-absorption and excretion ...Despite being known as resistant proteins, peanut allergens (Ara h 1 and Ara h 2) can be digested and cause allergic reactions. Making the allergens more resistant to digestion may aid in non-absorption and excretion of the allergens. Our objectives were to make Ara h 1 and Ara h 2 more resistant to digestion and test them in a model system using trypsin as the digestive enzyme. The resistant allergens were prepared by covalently attaching p-aminobenzamidine (pABA), a protease inhibitor, to peanut allergens in an extract or on a PVDF membrane using glutaraldehyde, and were then tested for resistance to trypsin digestion. SDS-PAGE and Western blot were performed to determine the allergenic capacity of the modified allergens. A control was prepared using glycine instead. Results showed that Ara h 2, when covalently attached with pABA, was more resistant to trypin digestion than the native allergen. Similarly, Ara h 1, prepared on a PVDF membrane and treated with pABA, displayed a resistance to trypsin digestion. Treatment of the allergens with glycine (a control) instead of pABA showed that the modified allergens were as digestible as native allergens. Blot assays showed that the pABA-treated allergens exhibited a lower allergenic capacity than native allergens. It was concluded that pABA, when attached to peanut allergen Ara h 1 or Ara h 2, inhibited digestion of the allergen by trypsin and reduced their allergenic capacity as well.展开更多
Objective:To compare the antibacterial activity and antiseptic effect of ethanol extract of Peganum harmala L.(P.harmala)seeds and Betadine on eight reference strains of Streptococcus pneumoniae,Salmonella typhimurium...Objective:To compare the antibacterial activity and antiseptic effect of ethanol extract of Peganum harmala L.(P.harmala)seeds and Betadine on eight reference strains of Streptococcus pneumoniae,Salmonella typhimurium,Escherichia coli,Corynebacterium pseudotuberculosis,Klebsiella pneumoniae,Staphylococcus aureus,Micrococcus luteus which are known to cause different types of skin infections,and Corynebacterium pseudotuberculosis isolated from an abscess on horse's neck.Methods:The antibacterial activity was assessed using a disc diffusion method.The minimum inhibitory concentration was tested by serial dilution method and the percentage of bacterial growth inhibition by absorbance microplate reader device.The minimum bactericidal concentration was then recorded.Clinical outcomes were obtained through washed up healing time of longitudinal and surface skin on the back of 16 rats with concentrations of 10,50,100,150 and 500 mg/mL of P.harmala extract.Results:The results of in vitro experiments showed that the lowest minimum inhibitory concentration(0.68-1.3 mg/mL)and minimum bactericidal concentration(1.3-5 mg/mL)values were observed in the ethanol extract of P.harmala seeds.Also the results of in vivo experiment showed that wound healing in the concentration of 50 mg/mL of this plant extract was better and quicker than Betadine.Conclusions:This study confirmed that ethanol extract of P.harmala has appropriate effect on the microorganisms and the healing of skin wounds in comparison with Betadine.展开更多
Objective:To identify bacteria isolated from diseased Southern flounder and determine whether they are virulent to channel catfish and Nile tilapia.Methods:Gram-negative bacteria isolates were recovered from five tiss...Objective:To identify bacteria isolated from diseased Southern flounder and determine whether they are virulent to channel catfish and Nile tilapia.Methods:Gram-negative bacteria isolates were recovered from five tissues of diseased Southern flounder(Paralichthys lethostigma).The isolates were subjected to biochemical and molecular identification followed by virulence study in fish.Results:Based on biochemical analysis,the 25 isolates were found to share homologies with either Edwardsiella tarda(E.tarda)or Aeromonas hydrophila(A.hydrophila).Based on sequencing results of partial 16S rRNA gene,15 isolates shared 100%identities with the 16S rRNA sequence of previously identified E.tarda strain TX1,whereas the other 10 isolates shared 100%identities with the 16S rRNA sequence of previously identified A.hydrophila strain An4.When healthy fish were exposed to flounder isolate by intracoelomic injection,the LD50 values of flounder isolate E.tarda to channel catfish or Nile tilapia[(10±2)g]were 6.1×10^(4)and 1.1×10^(7)CFU/fish,respectively,whereas that of flounder isolate A.hydrophila to channel catfish and Nile tilapia were 1.4×10^(7)and 5.6×10^(7)CFU/fish,respectively.Conclusions:This is the first report that E.tarda and A.hydrophila isolated from diseased Southern flounder are virulent to catfish and tilapia.展开更多
文摘This study evaluated transfer of maternal lysozyme and immunoglobulin (IgM) against Lactococcus garviea, the causative agent of lactococcosis to eggs and larvae in rainbow trout. Changes in circulating lysozyme and IgM during development of eggs and larvae were measured by a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus and enzyme-linked immunosorbent assay (ELISA) respectively. For doing this, twelve broodstocks were injected weekly with 2.5 mg·kg-1 letrozole (an endocrine disrupter component) two months before spawning season and vaccinated intraperitoneally (i.p) with a bacterin (inactivated L. garviae) one month before spawning. Twelve broodstocks for vaccination and twelve female rainbow trouts as control group were also immiunised (i.p) with the bacterin and injected (i.p) with PBS respectively. Results showed that at day 8 after hatching, lysozyme and IgM levels during pre-larval stages decreased gradually, as yolks were absorbed. Lysozyme and IgM levels were significantly higher in the letrozole injected immiunised parents 30 days after immunisation as well as their larvae compared to the control group (p L. garviae) (one month before spawning) in maternal transfer of lysozyme and IgM levels to eggs and larvae.
文摘This study evaluated efficacy of maternal and larval immunisation against Lactococcus garviae infection and on the lysozyme and immunoglobulin (IgM) levels in rainbow trout Oncorhynchus mykiss (Walaum). Forty-eight-day-old larvae (mean weight 96 mg) originating from injected weekly with letrozole and immunised, only immunised and non-immunised parents were experimentally infected with the L. garvieae, and the mortality rate was recorded daily. Larvae were vaccinated by immersion at 58 days post hatch with live L. garvieae (109 cells/mL) for 15 min. Every third day post larvae vaccination, two larvae from each group were collected for analysis lysozyme (by a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus) and IgM (by enzyme-linked immunosorbent assay (ELISA)) parameters. Vaccinated and control larvae were tested for protection against L. garvieae 30 days post larvae immunization when the larvae were 88 days old. Larvae were challenged by bath exposure with live L. garvieae (109 cells/mL) for 2 min and monitored for mortality for at least 10 days following challenge. The challenge experiment with L. garvieae showed a significant reduction in larvae from immunised (54.44% ± 0.64%) and injected weekly with letrozole and immunised fish (52.96% ± 0.97%) compared to larvae from control fish (62.96% ± 2.22%). Vaccinated larvae originated from injected weekly with letrozole and immunised parents showed significantly higher lysozyme activity compared to other fish groups. Vaccinated larvae showed significantly less mortality compared to controls. The relative percent survival (RPS) values of larvae from only immunised, injected weekly with letrozole and immunised and non-immunised parents vaccinated with L. garvieae were 67.36% ± 0.9%, 68.05% ± 0.66% and 48.27% ± 2.79% respectively. The results indicate that the effect of maternal immunization rainbow trout against L. garvieae infection by eliciting the immune responses as indicated by an increase in the IgM level and lysozyme activity.
文摘This study was carried out to investigate the effect of different concentrations of garlic (Allium sativum L.) extract in fish diet on survival rate, digestive enzymes and some biochemical parameters of Mugil cephalus larvae. Three hundred and sixty fish with mean weight 0.45 g were randomly divided into equal four groups;each one contained 3 replicates. Fish was fed with diets containing 0% (control), 0.5%, 1% and 3% concentrations of garlic extract (GE) in diet. 30 days after feeding, survival rate, different biochemical (larvae extract total protein, albumin, globulin, glucose, cholesterol and triglyceride) parameters and digestive enzyme activity (lipase, protease and amylase) were evaluated. There was a significant increase in survival rate of all groups fed with GE as compared to the control diet (P < 0.05). The administration of A. sativum in all levels significantly decreased (P < 0.05) the content of cholesterol, triglyceride and glucose in larvae extract. Also total protein, albumin and globulin levels had significantly increased in all groups fed GE (P < 0.05). The highest total protein (2.13 ± 0.12 g/dL), albumin (0.37 ± 0 g/dL), globulin (1.76 ± 0.12 g/dL), amylase (9.25 ± 0.14 U/mg protein), protease (4.20 ± 0.08 U/mg protein) and lipase (2.62 ± 0.14 U/mg protein) and the lowest serum triglyceride (22.78 ± 0.20 mg/dL), glucose (8.76 ± 0.09 mg/dL), cholesterol (3.69 ± 0.07 mg/dL) levels were observed in fish fed 3% GE in diet. Garlic inclusion in fish diet at 3% concentration is therefore beneficial for use in aquaculture to improve the general health and digestive enzyme activity of M. cephalus larvae.
文摘A chitinase was identified in extracellular products of a virulent?Aeromonas hydrophila?isolated from diseased channel catfish (Ictalurus punctatus). Recombinant chitinase (rChi-Ah) was produced in?Escherichia coli. Purified rChi-Ah had optimal activity at temperature of 42℃?and pH 6.5. The affinity (Km) for chitosan was 4.18 mg·ml-1?with?Vmax?of 202.5 mg·min-1·mg-1. With colloidal chitin as substrate, rChi-Ah generated N,N’-diacetyl-glucosamine predominantly. Conversion of chitosan (≥75% deacetylated) by rChi-Ah revealed five major products: 2 to 4 units of glucosamine, all of which had at least one acetyl group. It was determined that N-acetylated glucosamine was the recognition and cleavage site of rChi-Ah;the minimal and maximal cleavages were two and four glucosamine units, respectively. Functional analysis of rChi-Ah suggests that?A. hydrophilachitinase is a bioactive chitinolytic enzyme, which may benefit the pathogen for survival and/or infection.
文摘Despite being known as resistant proteins, peanut allergens (Ara h 1 and Ara h 2) can be digested and cause allergic reactions. Making the allergens more resistant to digestion may aid in non-absorption and excretion of the allergens. Our objectives were to make Ara h 1 and Ara h 2 more resistant to digestion and test them in a model system using trypsin as the digestive enzyme. The resistant allergens were prepared by covalently attaching p-aminobenzamidine (pABA), a protease inhibitor, to peanut allergens in an extract or on a PVDF membrane using glutaraldehyde, and were then tested for resistance to trypsin digestion. SDS-PAGE and Western blot were performed to determine the allergenic capacity of the modified allergens. A control was prepared using glycine instead. Results showed that Ara h 2, when covalently attached with pABA, was more resistant to trypin digestion than the native allergen. Similarly, Ara h 1, prepared on a PVDF membrane and treated with pABA, displayed a resistance to trypsin digestion. Treatment of the allergens with glycine (a control) instead of pABA showed that the modified allergens were as digestible as native allergens. Blot assays showed that the pABA-treated allergens exhibited a lower allergenic capacity than native allergens. It was concluded that pABA, when attached to peanut allergen Ara h 1 or Ara h 2, inhibited digestion of the allergen by trypsin and reduced their allergenic capacity as well.
文摘Objective:To compare the antibacterial activity and antiseptic effect of ethanol extract of Peganum harmala L.(P.harmala)seeds and Betadine on eight reference strains of Streptococcus pneumoniae,Salmonella typhimurium,Escherichia coli,Corynebacterium pseudotuberculosis,Klebsiella pneumoniae,Staphylococcus aureus,Micrococcus luteus which are known to cause different types of skin infections,and Corynebacterium pseudotuberculosis isolated from an abscess on horse's neck.Methods:The antibacterial activity was assessed using a disc diffusion method.The minimum inhibitory concentration was tested by serial dilution method and the percentage of bacterial growth inhibition by absorbance microplate reader device.The minimum bactericidal concentration was then recorded.Clinical outcomes were obtained through washed up healing time of longitudinal and surface skin on the back of 16 rats with concentrations of 10,50,100,150 and 500 mg/mL of P.harmala extract.Results:The results of in vitro experiments showed that the lowest minimum inhibitory concentration(0.68-1.3 mg/mL)and minimum bactericidal concentration(1.3-5 mg/mL)values were observed in the ethanol extract of P.harmala seeds.Also the results of in vivo experiment showed that wound healing in the concentration of 50 mg/mL of this plant extract was better and quicker than Betadine.Conclusions:This study confirmed that ethanol extract of P.harmala has appropriate effect on the microorganisms and the healing of skin wounds in comparison with Betadine.
基金Supported by the USDA/ARS CRIS project#6420-32000-024-00D.
文摘Objective:To identify bacteria isolated from diseased Southern flounder and determine whether they are virulent to channel catfish and Nile tilapia.Methods:Gram-negative bacteria isolates were recovered from five tissues of diseased Southern flounder(Paralichthys lethostigma).The isolates were subjected to biochemical and molecular identification followed by virulence study in fish.Results:Based on biochemical analysis,the 25 isolates were found to share homologies with either Edwardsiella tarda(E.tarda)or Aeromonas hydrophila(A.hydrophila).Based on sequencing results of partial 16S rRNA gene,15 isolates shared 100%identities with the 16S rRNA sequence of previously identified E.tarda strain TX1,whereas the other 10 isolates shared 100%identities with the 16S rRNA sequence of previously identified A.hydrophila strain An4.When healthy fish were exposed to flounder isolate by intracoelomic injection,the LD50 values of flounder isolate E.tarda to channel catfish or Nile tilapia[(10±2)g]were 6.1×10^(4)and 1.1×10^(7)CFU/fish,respectively,whereas that of flounder isolate A.hydrophila to channel catfish and Nile tilapia were 1.4×10^(7)and 5.6×10^(7)CFU/fish,respectively.Conclusions:This is the first report that E.tarda and A.hydrophila isolated from diseased Southern flounder are virulent to catfish and tilapia.
