Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruc...Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruction of monolayer of cells appeared after seven days post infection （dpi）. Virus titer was different for each strain, TCIDso ranged from 102.7 to 1069, and LDs0 from 1015 to 1075. Five NNV strains named QN 02, QN 05, QN 07, ND 11 and KH 05 had higher virulence than the other three, the first causing 100% mortality in experimental fish 3-5 dpi. NNV KH 05 had the highest antigenic similarity, and it was inactivated completely by 0.2% formalin, 0.002 mol/L binary ethylenimine （BEI） and 0.1% beta-propiolactone. The neutralization antibody titer obtained in fish of groups immunized by BEI 0.002 M and beta-propiolactone 0.1% inactivated virus was four to eight times higher than that of the group treated with the formalin inactivated virus. The antibody titer in fish immunized with beta-propiolactone inactivated virus was more persistent. The efficacy of vaccines developed from beta-propiolactone inactivated virus and aluminium hydroxide （AH） or aluminum phosphate （AP） was observed by intramuscularly immunizing Epinephelusfuscoguttatus size 1.5 cm. Neutralizing antibodies appeared in vaccinated fish on 10th day post-immunization （dpi） at a dilution of 1：16; 1：32 and highest levels were reached on 30-45 dpi, at dilutions of 1：256 and 1：512, after treatment with AH and AP vaccine, respectively. The relative percent of survival （RPS） of vaccine at 30 dpi was highest with challenge doses 0.2-1 × 10^6.8 TCIDs0, the RPS varied from 80%-83.3% in both groups of AH and AP immunization. This result provides the basis for developing a vaccine against NNA disease.展开更多
The susceptibility of different tissues and organs from strawberry plants, cv ＂Camarosa＂, to Colletotrichum acutatum was tested using a severity index based on infection response. Symptoms developed on inoculated ti...The susceptibility of different tissues and organs from strawberry plants, cv ＂Camarosa＂, to Colletotrichum acutatum was tested using a severity index based on infection response. Symptoms developed on inoculated tissues were characterized along 30 days. Flowers, except sepals, petioles and fruits were the most susceptible organs to the pathogen and they became necrotic tissues at 30 days post inoculation （dpi）. Also, well-developed acervuli, which produced masses of orange-pink spores, were observed on these infected organs. An asymptomatic stage or latency phase was observed in green and white strawberry fruits. In spite of they were inoculated anthracnose symptoms were observed only when they became red fruits. On the other hand, strawberry leaves and sepals were resistant to infection by C. acutatum and only small flecks or light brown spots were observed reaching a size of 1 to 5 mm at 30 dpi. Likewise, the susceptibility of stolons and crowns to C. acutatum was evaluated as intermediate at 30 dpi. Finally, the infection process of the fungus on strawberry leaves and petioles was studied using light and electron microscopy. Pre-penetration events were similar on both, leaves and petioles： However, differences between colonization of strawberry leaves and petioles by C. acutatum were observed.展开更多
Twenty isolates of Fusarium oxysporum f. sp. ciceris were isolated from wilted chickpea plants obtained from different districts of north part of Iraq to assess variability in pathogenicity of the populations. Each is...Twenty isolates of Fusarium oxysporum f. sp. ciceris were isolated from wilted chickpea plants obtained from different districts of north part of Iraq to assess variability in pathogenicity of the populations. Each isolate was tested on 12 differential chickpea varieties. Isolates showed highly significant variation in wilt severity on the differential varieties. Based on the reaction types that induced on differential varieties, isolates were grouped into four groups, First group included isolates FocSl, FocQ7, FocQ 10, FocFI3, FocH 17 and FocHl8; the second group included isolates FocS2, FocS3, FocS4, FocQ5, FocQ8, FocQ9, FocF11, FocF12, FocFl4 and FocH19; the third group included isolates FocF15, FocHl6, FocH20; where the isolate FocQ6 was placed in the fourth group. Results showed that the percentage of genetic similarity was ranged 42% to 100% and was 42% between the first group and other groups and 72% between the three groups the rest and thus this indicate the presence of four races of the fungus which are O, 4, 5 and 1B/C, this represent the first record of these races in lraq.展开更多
文摘Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruction of monolayer of cells appeared after seven days post infection （dpi）. Virus titer was different for each strain, TCIDso ranged from 102.7 to 1069, and LDs0 from 1015 to 1075. Five NNV strains named QN 02, QN 05, QN 07, ND 11 and KH 05 had higher virulence than the other three, the first causing 100% mortality in experimental fish 3-5 dpi. NNV KH 05 had the highest antigenic similarity, and it was inactivated completely by 0.2% formalin, 0.002 mol/L binary ethylenimine （BEI） and 0.1% beta-propiolactone. The neutralization antibody titer obtained in fish of groups immunized by BEI 0.002 M and beta-propiolactone 0.1% inactivated virus was four to eight times higher than that of the group treated with the formalin inactivated virus. The antibody titer in fish immunized with beta-propiolactone inactivated virus was more persistent. The efficacy of vaccines developed from beta-propiolactone inactivated virus and aluminium hydroxide （AH） or aluminum phosphate （AP） was observed by intramuscularly immunizing Epinephelusfuscoguttatus size 1.5 cm. Neutralizing antibodies appeared in vaccinated fish on 10th day post-immunization （dpi） at a dilution of 1：16; 1：32 and highest levels were reached on 30-45 dpi, at dilutions of 1：256 and 1：512, after treatment with AH and AP vaccine, respectively. The relative percent of survival （RPS） of vaccine at 30 dpi was highest with challenge doses 0.2-1 × 10^6.8 TCIDs0, the RPS varied from 80%-83.3% in both groups of AH and AP immunization. This result provides the basis for developing a vaccine against NNA disease.
文摘The susceptibility of different tissues and organs from strawberry plants, cv ＂Camarosa＂, to Colletotrichum acutatum was tested using a severity index based on infection response. Symptoms developed on inoculated tissues were characterized along 30 days. Flowers, except sepals, petioles and fruits were the most susceptible organs to the pathogen and they became necrotic tissues at 30 days post inoculation （dpi）. Also, well-developed acervuli, which produced masses of orange-pink spores, were observed on these infected organs. An asymptomatic stage or latency phase was observed in green and white strawberry fruits. In spite of they were inoculated anthracnose symptoms were observed only when they became red fruits. On the other hand, strawberry leaves and sepals were resistant to infection by C. acutatum and only small flecks or light brown spots were observed reaching a size of 1 to 5 mm at 30 dpi. Likewise, the susceptibility of stolons and crowns to C. acutatum was evaluated as intermediate at 30 dpi. Finally, the infection process of the fungus on strawberry leaves and petioles was studied using light and electron microscopy. Pre-penetration events were similar on both, leaves and petioles： However, differences between colonization of strawberry leaves and petioles by C. acutatum were observed.
文摘Twenty isolates of Fusarium oxysporum f. sp. ciceris were isolated from wilted chickpea plants obtained from different districts of north part of Iraq to assess variability in pathogenicity of the populations. Each isolate was tested on 12 differential chickpea varieties. Isolates showed highly significant variation in wilt severity on the differential varieties. Based on the reaction types that induced on differential varieties, isolates were grouped into four groups, First group included isolates FocSl, FocQ7, FocQ 10, FocFI3, FocH 17 and FocHl8; the second group included isolates FocS2, FocS3, FocS4, FocQ5, FocQ8, FocQ9, FocF11, FocF12, FocFl4 and FocH19; the third group included isolates FocF15, FocHl6, FocH20; where the isolate FocQ6 was placed in the fourth group. Results showed that the percentage of genetic similarity was ranged 42% to 100% and was 42% between the first group and other groups and 72% between the three groups the rest and thus this indicate the presence of four races of the fungus which are O, 4, 5 and 1B/C, this represent the first record of these races in lraq.
