RESUMO
The green peach aphid (Myzus persicae), a plant pest, and gray mold disease, caused by Botrytis cinerea, affect vegetables and fruit crops all over the world. To control this aphid and mold, farmers typically rely on the use of chemical insecticides or fungicides. However, intensive use of these chemicals over many years has led to the development of resistance. To overcome this problem, there is a need to develop alternative control methods to suppress populations of this plant pest and pathogen. Recently, potential roles have been demonstrated for entomopathogenic fungi in endophytism, phytopathogen antagonism, plant growth promotion, and rhizosphere colonization. Here, the antifungal activities of selected fungi with high virulence against green peach aphids were tested to explore their potential for the dual control of B. cinerea and M. persicae. Antifungal activities against B. cinerea were evaluated by dual culture assays using both aerial conidia and cultural filtrates of entomopathogenic fungi. Two fungal isolates, Beauveria bassiana SD15 and Metarhizium anisopliae SD3, were identified as having both virulence against aphids and antifungal activity. The virulence of these isolates against aphids was further tested using cultural filtrates, blastospores, and aerial conidia. The most virulence was observed in the simultaneous treatment with blastospores and cultural filtrate. These results suggest that the two fungal isolates selected in this study could be used effectively for the dual control of green peach aphids and gray mold for crop protection.
Assuntos
Afídeos , Beauveria , Botrytis , Colo , Proteção de Cultivos , Fazendeiros , Frutas , Fungos , Inseticidas , Metarhizium , Plantas , Prunus persica , Rizosfera , Esporos Fúngicos , Verduras , VirulênciaRESUMO
Nosema ceranae is an obligate intracellular fungal parasite that causes mortality in honey bees and enhances the susceptibility of honey bees to other pathogens. Efficient purification of Nosema spores from the midgut of infected honey bees is very important because Nosema is non-culturable and only seasonably available. To achieve a higher yield of spores from honey bees, in this study, we considered that the initial release of spores from the midgut tissues was the most critical step. The use of 2 mm beads along with enzymatic treatment with collagenase and trypsin enhanced the homogenization of tissues and the yield of released spores by approximately 2.95 times compared with the use of common 3 mm beads alone. The optimal time for the enzyme treatment was determined to be 1 hr as measured by the yield and viability of the spores. A one-step filtration using a filter paper with an 8–11 µm pore size was sufficient for removing cell debris. This method may be useful to purify not only N. ceranae spores but also other Nosema spp. spores.
Assuntos
Abelhas , Colagenases , Filtração , Mel , Métodos , Mortalidade , Nosema , Parasitos , Estações do Ano , Esporos , TripsinaRESUMO
BACKGROUND: Many strains of Leptospira interrogans have been isolated in Korea since 1984. Most isolates were identified as serovar lai by serological methods. The pulsed field gel electrophoresis (PFGE) patterns of Korean isolates have not been investigated currently. METHODS: 29 reference strains and 29 Korean isolates of Leptospira interrogans were characterized by PFGE. Chromosomes were digested by the Not I restriction enzyme and subsequently PFGE was performed in CHEF-DRII (Bio Rad Lab) with 3 pulse times (30 seconds 13 hours, 60 seconds 13 hours, 120 seconds 14 hours) at 150 V (4.5 V/cm). RESULTS: 12 serogroup reference strains and most 17 serovars reference strains in the serogroup Icterohaemoffhagie showed the unique Not I restriction patterns. Most isolates identified serologically as serovar lai showed the same PFGE patterns as the serovar lai reference strain. The strain HM3 and 18R identified serologically as new serovars yeonchon and hongchon respectively showed the same PFGE patterns as serovar lai. The strain AP31, CH88-19 and NR13 that were different from serovar lai by serological methods showed the PFGE patterns indistinguishable from serovar lai reference strain. The strain HY2 that was identified as serovar lai, and the strain 30R that was different from serovar lai serologically showed the PFGE patterns slightly different from serovar lai reference strain. CONCLUSION: The PFGE profile of most Korean isolates Leptospira interrogans serologically identified as serovar lai is identical to the reference strain serovar lai. PFGE analysis thus may be applied to identify serovar of isolates and to investigate the genetic diversity of related serovar.
Assuntos
DNA , Eletroforese em Gel de Campo Pulsado , Variação Genética , Coreia (Geográfico) , Leptospira interrogans , LeptospiraRESUMO
BACKGROUND: Many strains of Leptospira interrogans have been isolated in Korea since 1984. Most isolates were identified as serovar lai by serological methods. The pulsed field gel electrophoresis (PFGE) patterns of Korean isolates have not been investigated currently. METHODS: 29 reference strains and 29 Korean isolates of Leptospira interrogans were characterized by PFGE. Chromosomes were digested by the Not I restriction enzyme and subsequently PFGE was performed in CHEF-DRII (Bio Rad Lab) with 3 pulse times (30 seconds 13 hours, 60 seconds 13 hours, 120 seconds 14 hours) at 150 V (4.5 V/cm). RESULTS: 12 serogroup reference strains and most 17 serovars reference strains in the serogroup Icterohaemoffhagie showed the unique Not I restriction patterns. Most isolates identified serologically as serovar lai showed the same PFGE patterns as the serovar lai reference strain. The strain HM3 and 18R identified serologically as new serovars yeonchon and hongchon respectively showed the same PFGE patterns as serovar lai. The strain AP31, CH88-19 and NR13 that were different from serovar lai by serological methods showed the PFGE patterns indistinguishable from serovar lai reference strain. The strain HY2 that was identified as serovar lai, and the strain 30R that was different from serovar lai serologically showed the PFGE patterns slightly different from serovar lai reference strain. CONCLUSION: The PFGE profile of most Korean isolates Leptospira interrogans serologically identified as serovar lai is identical to the reference strain serovar lai. PFGE analysis thus may be applied to identify serovar of isolates and to investigate the genetic diversity of related serovar.
Assuntos
DNA , Eletroforese em Gel de Campo Pulsado , Variação Genética , Coreia (Geográfico) , Leptospira interrogans , LeptospiraRESUMO
Murine typhus is an acute febrile illness caused by Rickettsia typhi. It is one of the four major acute febrile illnesses in Korea during autumn. To study a species-specific antigen of R. typhi, two clinical isolates (87-91 and 87-100) and two reference strains (VR-144 and VR-738) were analyzed by mouse antisera and monoclonal antibodies (MAbs). On SDS- polyacrylamide gel electrophoresis (PAGE), R. typhi showed major antigen bands of 135, 80, 75, 64, 47, 22, and 19 kDa and these bands differed with those of other species. On Western blot analysis, the MAbs reacting only with R. typhi could only detect 135 kDa protein. The 135 kDa protein appeared to be the species-specific antigen. Other MAbs showing cross-reactivity with R. prowazekii reacted with 135 kDa protein in fresh culture supernatant of R. typhi infected host cell. However, the cross-reacting antibody did also react with smaller protein bands, most of which seem to be degradation products of the 135 kDa protein since they increase in old protein stocks purified from R. typhi harvested from infected host cell. These suggest that 135 kDa protein is unstable and the R. typhi specific epitopes are located at the regions of 135 kDa protein that are removed when the protein is degraded. The 135 kDa protein or its specific and stable recombinant protein would serve an important target for the development of vaccine and specific diagnostic antigen.
Assuntos
Animais , Camundongos , Anticorpos Monoclonais , Western Blotting , Eletroforese em Gel de Poliacrilamida , Epitopos , Soros Imunes , Coreia (Geográfico) , Rickettsia typhi , Rickettsia , Tifo Endêmico Transmitido por PulgasRESUMO
To use recombinant viruses with wider host range as viral insecticides, we investigated the characteristics and pathogenicity of host range expanded recombinant viruses in insect cells. We compared host range expanded recombinant viruses, RecS-B6 and RecB-8, constructed by cotransfection of Autographa californica nuclear polyhedrosis virus (AcNPV) and Bombyx mori NPV (BmNPV), to host range expanded AcNPV, Ac-BH, by substitution of the 0.6 Kb fragment of the BmNPV helicase gene. Restriction endonuclease profiles of RecS-B6 and RecB-8 DNAs were different from those of parent viruses. Nucleotide sequence analysis of the 0.6 Kb region in the putative helicase gene of RecS-B6 and RecB-8 showed that their structures were identical to the counterpart region of BmNPV Comparison of viral replication of these recombinant viruses in Sf-21 and BmN-4 cells showed that Ac-BH, compared to wild type viruses, replicated well in BmN-4 cells but poorly in Sf-21 cells. In contrast, RecS-B6 and RecB-8 replicated relatively well in both cells compared to parent viruses. These results may imply that random genomic recombinant viruses, RecS-B6 and RecB-8, possess better potential as viral pesticides than helicase-mediated recombinant virus, Ac-BH.