The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Elke Genersch - One of the best experts on this subject based on the ideXlab platform.
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Biology of Paenibacillus Larvae, a deadly pathogen of honey bee Larvae
Applied Microbiology and Biotechnology, 2016Co-Authors: Julia Ebeling, Gillian Hertlein, Henriette Knispel, Anne Fünfhaus, Elke GenerschAbstract:The gram-positive bacterium Paenibacillus Larvae is the etiological agent of American Foulbrood of honey bees, a notifiable disease in many countries. Hence, P. Larvae can be considered as an entomopathogen of considerable relevance in veterinary medicine. P. Larvae is a highly specialized pathogen with only one established host, the honey bee larva. No other natural environment supporting germination and proliferation of P. Larvae is known. Over the last decade, tremendous progress in the understanding of P. Larvae and its interactions with honey bee Larvae at a molecular level has been made. In this review, we will present the recent highlights and developments in P. Larvae research and discuss the impact of some of the findings in a broader context to demonstrate what we can learn from studying “exotic” pathogens.
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involvement of secondary metabolites in the pathogenesis of the american foulbrood of honey bees caused by Paenibacillus Larvae
Natural Product Reports, 2015Co-Authors: Sebastian Alexander Muller, Elke Genersch, Eva Garciagonzalez, Roderich D. SüssmuthAbstract:The Gram-positive, spore-forming bacterium Paenibacillus Larvae (P. Larvae) is the causative agent of the epizootic American Foulbrood (AFB), a fatal brood disease of the western honey bee (Apis mellifera). AFB is one of the most destructive honey bee diseases since it is not only lethal for infected Larvae but also for the diseased colonies. Due to the high impact of honey bees on ecology and economy this epizootic is a severe and pressing problem. Knowledge about virulence mechanisms and the underlying molecular mechanisms remain largely elusive. Recent genome sequencing of P. Larvae revealed its potential to produce unknown secondary metabolites, like nonribosomal peptides and peptide-polyketide hybrids. This article highlights recent findings on secondary metabolites synthesized by P. Larvae and discusses their role in virulence and pathogenicity towards the bee Larvae.
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Molecular pathogenesis of American Foulbrood: how Paenibacillus Larvae kills honey bee Larvae
Current opinion in insect science, 2015Co-Authors: Lena Poppinga, Elke GenerschAbstract:American Foulbrood caused by Paenibacillus Larvae is one of the unsolved health problems honey bee colonies are suffering from. In the recent past, considerable progress has been achieved in understanding molecular details of P. Larvae infections of honey bee Larvae. This was facilitated by the development of molecular tools for manipulating P. Larvae and by the availability of complete genome sequences of different P. Larvae genotypes. We here report on several peptides and proteins that have recently been identified, biochemically analyzed, and proposed to act as virulence factors of P. Larvae. For some of them, experimental proof for their role as virulence factor has been provided allowing presenting a preliminary model for the molecular pathogenesis of American Foulbrood.
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paenilamicin structure and biosynthesis of a hybrid nonribosomal peptide polyketide antibiotic from the bee pathogen Paenibacillus Larvae
Angewandte Chemie, 2014Co-Authors: Sebastian Alexander Muller, Andi Mainz, Elke Genersch, Eva Garciagonzalez, Gillian Hertlein, Nina C Heid, Eva Mosker, Hans Van Den Elst, Herman S Overkleeft, Roderich D. SüssmuthAbstract:The spore-forming bacterium Paenibacillus Larvae is the causative agent of American Foulbrood (AFB), a fatal disease of honey bees that occurs worldwide. Previously, we identified a complex hybrid nonribosomal peptide/polyketide synthesis (NRPS/PKS) gene cluster in the genome of P. Larvae. Herein, we present the isolation and structure elucidation of the antibacterial and antifungal products of this gene cluster, termed paenilamicins. The unique structures of the paenilamicins give deep insight into the underlying complex hybrid NRPS/PKS biosynthetic machinery. Bee larval co-infection assays reveal that the paenilamicins are employed by P. Larvae in fighting ecological niche competitors and are not directly involved in killing the bee Larvae. Their antibacterial and antifungal activities qualify the paenilamicins as attractive candidates for drug development.
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proteome analysis of Paenibacillus Larvae reveals the existence of a putative s layer protein
Environmental Microbiology Reports, 2012Co-Authors: Anne Fünfhaus, Elke GenerschAbstract:Summary Honey bee pathology has attracted much interest recently due to the problems with honey bee declines in many regions of the world. American Foulbrood (AFB) caused by Paenibacillus Larvae is the most devastating bacterial brood disease of the Western honey bee (Apis mellifera) causing considerable economic losses to beekeepers worldwide. AFB outbreaks are mainly caused by two differentially virulent genotypes of P. Larvae, P. Larvae ERIC I and ERIC II. To better understand AFB pathogenesis and to complement already existing data from the genetic level we aimed at obtaining expression data from the protein level. We successfully developed a protocol for two-dimensional proteome analysis of P. Larvae with subsequent mass-spectrometry based protein sequencing. Based on the obtained master protein maps of P. Larvae genotypes ERIC I and II we identified the dominantly expressed cytosolic proteins of both genotypes, some of them presumably linked to pathogenesis and virulence. Comparing the master maps of both genotypes revealed differentially expressed proteins, i.e. a putative S-layer protein which is expressed by P. Larvae ERIC II but absent from the proteome of P. Larvae ERIC I. The implications of our findings for pathogenesis of AFB and virulence of P. Larvae will be discussed.
Ingemar Fries - One of the best experts on this subject based on the ideXlab platform.
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Novel lactic acid bacteria inhibiting Paenibacillus Larvae in honey bee Larvae
Apidologie, 2010Co-Authors: Eva Forsgren, Alejandra Vasquez, Tobias C. Olofsson, Ingemar FriesAbstract:We evaluated the antagonistic effects of newly identified lactic acid bacteria (LAB) in the genera Lactobacillus and Bifidobacterium, originating from the honey stomach, on the honey bee pathogen, Paenibacillus Larvae. We used inhibition assays on agar plates and honey bee larval bioassays to investigate the effects of honey bee LAB on P. Larvae growth in vitro and on AFB infection in vivo. The individual LAB phylotypes showed different inhibition properties against P. Larvae growth on agar plates, whereas a combination of all eleven LAB phylotypes resulted in a total inhibition (no visible growth) of P. Larvae. Adding the LAB mixture to the larval food significantly reduced the number of AFB infected Larvae in exposure bioassays. The results demonstrate that honey bee specific LAB possess beneficial properties for honey bee health. Possible benefits to honey bee health by enhancing growth of LAB or by applying LAB to honey bee colonies should be further investigated.
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horizontal transmission of Paenibacillus Larvae spores between honey bee apis mellifera colonies through robbing
Apidologie, 2008Co-Authors: Anders Lindstrom, Seppo Korpela, Ingemar FriesAbstract:Surprisingly little is known about transmission rates between honey bee colonies of Paenibacillus Larvae, the causative agent American foulbrood. We studied the rate of horizontal transmission of P. Larvae spores between colonies as a function of physical distance between colonies by culturing for the spores from sequential samples of adult bees. The results demonstrate a direct effect of distance to clinically diseased colonies on the probability of contracting high spore levels, as well as on the probability of developing clinically visible disease symptoms. The results also demonstrate that colonies may develop considerable spore densities on adult bees without exhibiting visible symptoms of disease. Furthermore, the data suggest that transmission of AFB between apiaries occur within 1 km distance from clinically diseased colonies, but is significantly lower at 2 km distance or longer when colonies dead from AFB are allowed to be robbed out.
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variability in germination and in temperature and storage resistance among Paenibacillus Larvae genotypes
Veterinary Microbiology, 2008Co-Authors: Eva Forsgren, Jevrosima Stevanovic, Ingemar FriesAbstract:There are several methods for cultivation of Paenibacillus Larvae, the causative agent of American foulbrood (AFB) in honey bees. Protocols for detection of sub-clinical levels of the bacterium from honey and bee samples include heat treatment of samples. The main objective of this study was to investigate if there is variability in temperature resistance among P. Larvae genotypes, potentially leading to biased diagnose and disease monitoring. The variation in germination and proliferation ability among type collection (N = 4) and field isolates (N = 4) of P. Larvae representing four different genotypes was investigated. Results demonstrate a significant variability between P. Larvae genotypes in germination rate on solid media as well as in endospore resistance to heat treatment and storage. It is concluded that strains of different genotypes should be included in evaluation of standard laboratory protocols for cultivation of P. Larvae to avoid bias in disease monitoring and quantification of the pathogen.
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reclassification of Paenibacillus Larvae subsp pulvifaciens and Paenibacillus Larvae subsp Larvae as Paenibacillus Larvae without subspecies differentiation
International Journal of Systematic and Evolutionary Microbiology, 2006Co-Authors: Elke Genersch, Sandra Rauch, Ainura Ashiralieva, Eva Forsgren, Jaana Pentikainen, Jochen Kilwinski, Ingemar FriesAbstract:A polyphasic taxonomic study of the two subspecies of Paenibacillus Larvae, Paenibacillus Larvae subsp. Larvae and Paenibacillus Larvae subsp. pulvifaciens, supported the reclassification of the subspecies into one species, Paenibacillus Larvae, without subspecies separation. Our conclusions are based on the analysis of six reference strains of P. Larvae subsp. pulvifaciens and three reference strains and 44 field isolates of P. Larvae. subsp. Larvae. The latter originated from brood or honey of clinically diseased honey bee colonies or from honey of both clinically diseased and asymptomatic colonies from Sweden, Finland and Germany. Colony and spore morphology, as well as the metabolism of mannitol and salicin, did not allow a clear identification of the two subspecies and SDS-PAGE of whole-cell proteins did not support the subspecies differentiation. For genomic fingerprinting, repetitive element-PCR fingerprinting using ERIC primers and PFGE of bacterial DNA were performed. The latter method is a high-resolution DNA fingerprinting method proven to be superior to most other methods for biochemical and molecular typing and has not previously been used to characterize P. Larvae. ERIC-PCR identified four different genotypes, while PFGE revealed two main clusters. One cluster included most of the P. Larvae subsp. Larvae field isolates, as well as all P. Larvae subsp. pulvifaciens reference strains. The other cluster comprised the pigmented variants of P. Larvae subsp. Larvae. 16S rRNA gene sequences were determined for some strains. Finally, exposure bioassays demonstrated that reference strains of P. Larvae subsp. pulvifaciens were pathogenic for honey bee Larvae, producing symptoms similar to reference strains of P. Larvae subsp. Larvae. In comparison with the type strain for P. Larvae subsp. Larvae, ATCC 9545T, the P. Larvae subsp. pulvifaciens strains tested were even more virulent, since they showed a shorter LT100. An emended description of the species is given.
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Vertical transmission of American foulbrood (Paenibacillus Larvae) in honey bees (Apis mellifera)
Veterinary Microbiology, 2006Co-Authors: Ingemar Fries, Annika Lindström, Seppo KorpelaAbstract:The mode of transmission between hosts (horizontal versus vertical) of disease agents is important for determination of the evolution of virulence in pathogens. For disease management, it is imperative that the epidemiology of the disease is understood and pathogen transmission rates between hosts is a key factor for this understanding. Surprisingly little is known about transmission rates in honey bee pathology. We have studied the rate of vertical transmission of Paenibacillus Larvae, the causative agent of American foulbrood (AFB) in honey bee colonies, as colonies reproduce by colony fission (swarming), by culturing for the spores from repetitive samples of adult bees. The results demonstrate vertical pathogen transmission to daughter swarms. The spore density declines over time in both mother colonies and daughter swarms if mother colonies do not exhibit clinical disease symptoms. Occasional positive samples more than a year post swarming, also in daughter swarms, indicate production of infectious spores from diseased Larvae, without clinical disease observable by beekeepers, and/or maintenance of infective spores in the hive environment, allowing both horizontal and vertical transmission to be maintained. The results suggest that the virulence of AFB, being lethal at colony level in contrast to other bee diseases shaped by evolution, could be dependent on apicultural practices and that the pathogen probably would be maintained without causing frequent colony mortality in a natural system.
Pablo Zunino - One of the best experts on this subject based on the ideXlab platform.
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lactobacillus kunkeei strains decreased the infection by honey bee pathogens Paenibacillus Larvae and nosema ceranae
Beneficial Microbes, 2017Co-Authors: Daniela Arredondo, Pablo Zunino, Martin Javier Eguaras, Loreley Castelli, Martin Pablo Porrini, Paula Melisa Garrido, Karina AntunezAbstract:Due to their social behaviour, honey bees can be infected by a wide range of pathogens including the microsporidia Nosema ceranae and the bacteria Paenibacillus Larvae. The use of probiotics as food additives for the control or prevention of infectious diseases is a widely used approach to improve human and animal health. In this work, we generated a mixture of four Lactobacillus kunkeei strains isolated from the gut microbial community of bees, and evaluated its potential beneficial effect on Larvae and adult bees. Its administration in controlled laboratory models was safe for Larvae and bees; it did not affect the expression of immune-related genes and it was able to decrease the mortality associated to P. Larvae infection in Larvae and the counts of N. ceranae spores from adult honey bees. These promising results suggest that this beneficial microorganism’s mixture may be an attractive strategy to improve bee health. Field studies are being carried out to evaluate its effect in naturally infected colo...
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metalloprotease production by Paenibacillus Larvae during the infection of honeybee Larvae
Microbiology, 2011Co-Authors: Karina Antunez, Matilde Anido, Daniela Arredondo, Pablo ZuninoAbstract:American foulbrood is a bacterial disease of worldwide distribution that affects Larvae of the honeybee Apis mellifera. The causative agent is the Gram-positive, spore-forming bacterium Paenibacillus Larvae. Several authors have proposed that P. Larvae secretes metalloproteases that are involved in the larval degradation that occurs after infection. The aim of the present work was to evaluate the production of a metalloprotease by P. Larvae during larval infection. First, the complete gene encoding a metalloprotease was identified in the P. Larvae genome and its distribution was evaluated by PCR in a collection of P. Larvae isolates from different geographical regions. Then, the complete gene was amplified, cloned and overexpressed, and the recombinant metalloprotease was purified and used to generate anti-metalloprotease antibodies. Metalloprotease production was evaluated by immunofluorescence and fluorescence in situ hybridization. The gene encoding a P. Larvae metalloprotease was widely distributed in isolates from different geographical origins in Uruguay and Argentina. Metalloprotease was detected inside P. Larvae vegetative cells, on the surface of P. Larvae spores and secreted to the external growth medium. Its production was also confirmed in vivo, during the infection of honeybee Larvae. This protein was able to hydrolyse milk proteins as described for P. Larvae, suggesting that could be involved in larval degradation. This work contributes to the knowledge of the pathogenicity mechanisms of a bacterium of great economic significance and is one step in the characterization of potential P. Larvae virulence factors.
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Paenibacillus Larvae enolase as a virulence factor in honeybee Larvae infection
Veterinary Microbiology, 2011Co-Authors: Karina Antunez, Jay D Evans, Matilde Anido, Daniela Arredondo, Pablo ZuninoAbstract:Paenibacillus Larvae is a gram-positive spore-forming bacteria, causative agent of American Foulbrood (AFB), a severe disease affecting Larvae of the honeybee Apis mellifera. In an attempt to detect potential virulence factors secreted by P. Larvae, we identified an enolase among different secreted proteins. Although this protein is a cytosolic enzyme involved in glycolytic pathways, it has been related to virulence. The aim of the present work was to evaluate its role during the infection of honeybee Larvae. Toxicity assays showed that enolase was highly toxic and immunogenic to honeybee Larvae. Its production was detected inside P. Larvae vegetative cells, on the surface of P. Larvae spores and secreted to the external growth medium. P. Larvae enolase production was also confirmed in vivo, during the infection of honeybee Larvae. This protein was able to hydrolyze milk proteins as described for P. Larvae, suggesting that could be involved in larval degradation, maybe through the plasmin(ogen) system. These results suggest that P. Larvae enolase may have a role in virulence and could contribute to a general insight about insect-pathogen interaction mechanisms.
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characterization of secreted proteases of Paenibacillus Larvae potential virulence factors involved in honeybee larval infection
Journal of Invertebrate Pathology, 2009Co-Authors: Karina Antunez, Jay D Evans, Matilde Anido, Geraldine Schlapp, Pablo ZuninoAbstract:Paenibacillus Larvae is the causative agent of American Foulbrood (AFB), the most severe bacterial disease that affects honeybee Larvae. AFB causes a significant decrease in the honeybee population affecting the beekeeping industry and agricultural production. After infection of Larvae, P. Larvae secretes proteases that could be involved in the pathogenicity. In the present article, we present the secretion of different proteases by P. Larvae. Inhibition assays confirmed the presence of metalloproteases. Two different proteases patterns (PP1 and PP2) were identified in a collection of P. Larvae isolates from different geographic origin. Forty nine percent of P. Larvae isolates showed pattern PP1 while 51% exhibited pattern PP2. Most isolates belonging to genotype ERIC I - BOX A presented PP2, most isolates belonging to ERIC I - BOX C presented PP1 although relations were not significant. Isolates belonging to genotypes ERIC II and ERIC III presented PP2. No correlation was observed between the secreted proteases patterns and geographic distribution, since both patterns are widely distributed in Uruguay. According to exposure bioassays, isolates showing PP2 are more virulent than those showing PP1, suggesting that difference in pathogenicity could be related to the secretion of proteases.
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phenotypic and genotypic characterization of Paenibacillus Larvae isolates
Veterinary Microbiology, 2007Co-Authors: Karina Antunez, Claudia Piccini, Susana Castrosowinski, Alexandre Soares Rosado, Lucy Seldin, Pablo ZuninoAbstract:Paenibacillus Larvae is the causative agent of American Foulbrood (AFB), a severe disease of honeybees (Apis melifera). The aim of this work was to develop a strategy for the subtyping and the epidemiological analysis of P. Larvae. Phenotypic characterisation, susceptibility to several antibiotics, electrophoresis of whole bacterial proteins, rep-PCR, ribotyping and DGGE were assessed using a collection of P. Larvae isolates from different Uruguayan and Argentinean locations. Results indicated that there are two P. Larvae genotypes circulating in Uruguay ERIC I-BOX A (worldwide distributed) and ERIC I-BOX C (exclusively detected in Argentina until this study). These results suggest that P. Larvae isolates had moved between Argentina and Uruguay, probably through the Uruguay River. Patterns of whole bacterial proteins, DGGE and ribotyping did not improve the P. Larvae intraspecific discrimination. Antibiotic susceptibility assays showed that 100% isolates were OTC-sensitive and 22% (belonging to ERIC I-BOX A group) were sulfisoxazole-resistant. This work may contribute to the elucidation of basic aspects related to the epidemiology of AFB in Uruguay and in the region.
Karina Antunez - One of the best experts on this subject based on the ideXlab platform.
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lactobacillus kunkeei strains decreased the infection by honey bee pathogens Paenibacillus Larvae and nosema ceranae
Beneficial Microbes, 2017Co-Authors: Daniela Arredondo, Pablo Zunino, Martin Javier Eguaras, Loreley Castelli, Martin Pablo Porrini, Paula Melisa Garrido, Karina AntunezAbstract:Due to their social behaviour, honey bees can be infected by a wide range of pathogens including the microsporidia Nosema ceranae and the bacteria Paenibacillus Larvae. The use of probiotics as food additives for the control or prevention of infectious diseases is a widely used approach to improve human and animal health. In this work, we generated a mixture of four Lactobacillus kunkeei strains isolated from the gut microbial community of bees, and evaluated its potential beneficial effect on Larvae and adult bees. Its administration in controlled laboratory models was safe for Larvae and bees; it did not affect the expression of immune-related genes and it was able to decrease the mortality associated to P. Larvae infection in Larvae and the counts of N. ceranae spores from adult honey bees. These promising results suggest that this beneficial microorganism’s mixture may be an attractive strategy to improve bee health. Field studies are being carried out to evaluate its effect in naturally infected colo...
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Natural strategies for the control of Paenibacillus Larvae, the causative agent of American foulbrood in honey bees: a review
Apidologie, 2017Co-Authors: Rosa Maria Alonso-salces, Karina Antunez, Noelia Melina Cugnata, Elisa Guaspari, Maria Celeste Pellegrini, Inés Aubone, Fiorella Giselle De Piano, Sandra Rosa FuselliAbstract:American foulbrood (AFB) is a severe bacterial disease that affects Larvae of honey bees (Apis mellifera). The causative agent of AFB is the spore-forming bacteria Paenibacillus Larvae. The use of antibiotics for the control of AFB has led to the appearance of resistant bacterial strains and residues in beehive products. Nowadays, antibiotics are legally banned in several countries, and the affected colonies have to be destroyed by burning the hives. Therefore, the development of alternative methods for the control and prevention of AFB is necessary. In this context, different natural strategies based on the application of essential oils, plant extracts, propolis, royal jelly, nonconventional natural molecules, bacteria, and bacteriocines, have been studied in vitro and in vivo for the prevention and control of P. Larvae. The experimental data achieved from these studies are reviewed and discussed in the present review, which intend to be a starting point for future research in the field.
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metalloprotease production by Paenibacillus Larvae during the infection of honeybee Larvae
Microbiology, 2011Co-Authors: Karina Antunez, Matilde Anido, Daniela Arredondo, Pablo ZuninoAbstract:American foulbrood is a bacterial disease of worldwide distribution that affects Larvae of the honeybee Apis mellifera. The causative agent is the Gram-positive, spore-forming bacterium Paenibacillus Larvae. Several authors have proposed that P. Larvae secretes metalloproteases that are involved in the larval degradation that occurs after infection. The aim of the present work was to evaluate the production of a metalloprotease by P. Larvae during larval infection. First, the complete gene encoding a metalloprotease was identified in the P. Larvae genome and its distribution was evaluated by PCR in a collection of P. Larvae isolates from different geographical regions. Then, the complete gene was amplified, cloned and overexpressed, and the recombinant metalloprotease was purified and used to generate anti-metalloprotease antibodies. Metalloprotease production was evaluated by immunofluorescence and fluorescence in situ hybridization. The gene encoding a P. Larvae metalloprotease was widely distributed in isolates from different geographical origins in Uruguay and Argentina. Metalloprotease was detected inside P. Larvae vegetative cells, on the surface of P. Larvae spores and secreted to the external growth medium. Its production was also confirmed in vivo, during the infection of honeybee Larvae. This protein was able to hydrolyse milk proteins as described for P. Larvae, suggesting that could be involved in larval degradation. This work contributes to the knowledge of the pathogenicity mechanisms of a bacterium of great economic significance and is one step in the characterization of potential P. Larvae virulence factors.
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Paenibacillus Larvae enolase as a virulence factor in honeybee Larvae infection
Veterinary Microbiology, 2011Co-Authors: Karina Antunez, Jay D Evans, Matilde Anido, Daniela Arredondo, Pablo ZuninoAbstract:Paenibacillus Larvae is a gram-positive spore-forming bacteria, causative agent of American Foulbrood (AFB), a severe disease affecting Larvae of the honeybee Apis mellifera. In an attempt to detect potential virulence factors secreted by P. Larvae, we identified an enolase among different secreted proteins. Although this protein is a cytosolic enzyme involved in glycolytic pathways, it has been related to virulence. The aim of the present work was to evaluate its role during the infection of honeybee Larvae. Toxicity assays showed that enolase was highly toxic and immunogenic to honeybee Larvae. Its production was detected inside P. Larvae vegetative cells, on the surface of P. Larvae spores and secreted to the external growth medium. P. Larvae enolase production was also confirmed in vivo, during the infection of honeybee Larvae. This protein was able to hydrolyze milk proteins as described for P. Larvae, suggesting that could be involved in larval degradation, maybe through the plasmin(ogen) system. These results suggest that P. Larvae enolase may have a role in virulence and could contribute to a general insight about insect-pathogen interaction mechanisms.
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characterization of secreted proteases of Paenibacillus Larvae potential virulence factors involved in honeybee larval infection
Journal of Invertebrate Pathology, 2009Co-Authors: Karina Antunez, Jay D Evans, Matilde Anido, Geraldine Schlapp, Pablo ZuninoAbstract:Paenibacillus Larvae is the causative agent of American Foulbrood (AFB), the most severe bacterial disease that affects honeybee Larvae. AFB causes a significant decrease in the honeybee population affecting the beekeeping industry and agricultural production. After infection of Larvae, P. Larvae secretes proteases that could be involved in the pathogenicity. In the present article, we present the secretion of different proteases by P. Larvae. Inhibition assays confirmed the presence of metalloproteases. Two different proteases patterns (PP1 and PP2) were identified in a collection of P. Larvae isolates from different geographic origin. Forty nine percent of P. Larvae isolates showed pattern PP1 while 51% exhibited pattern PP2. Most isolates belonging to genotype ERIC I - BOX A presented PP2, most isolates belonging to ERIC I - BOX C presented PP1 although relations were not significant. Isolates belonging to genotypes ERIC II and ERIC III presented PP2. No correlation was observed between the secreted proteases patterns and geographic distribution, since both patterns are widely distributed in Uruguay. According to exposure bioassays, isolates showing PP2 are more virulent than those showing PP1, suggesting that difference in pathogenicity could be related to the secretion of proteases.
Adriana Mónica Alippi - One of the best experts on this subject based on the ideXlab platform.
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partial characterization of bacteriocin like compounds from two strains of bacillus cereus with biological activity against Paenibacillus Larvae the causal agent of american foulbrood disease
Letters in Applied Microbiology, 2016Co-Authors: Jessica Minnaard, Adriana Mónica AlippiAbstract:American Foulbrood (AFB), caused by the spore-forming Gram-positive bacterium Paenibacillus Larvae, is the most severe bacterial disease affecting honeybees worldwide. Two bacterial isolates showing specific inhibitory activity against P. Larvae were identified as Bacillus cereus by 16S rDNA sequencing. Antagonistic compounds were obtained from cell-free supernatants of strains m6c and m387 growing on Trypticase Soy Broth and concentrated by NH4SO4 precipitation, ultrafiltration and butanol extraction. Both compounds were characterized as bacteriocin-like inhibitory substances (BLIS). BLISm6c and BLISm387 were stable at 70°C for 30 min and active in the pH range from 3 to 7. The antibacterial activity was completely lost at pH values higher than 8 or temperatures >80°C. Both BLIS have a narrow activity range and highly inhibit the growth of P. Larvae. BLISm6c and BLISm387 differ from each other and other BLIS reportedly produced by B. cereus with regard to their molecular weights, antibacterial activity, minimal inhibitory concentration values and sensitivity to degradative enzymes. The findings of this study suggest that BLISm6c and BLISm387 can potentially be used to control AFB. Significant and Impact of the Study An Integrated Pest Management (IPM) approach is needed to ensure the sustainability of the beekeeping industry due to the increasing demand for organic honey and the reduction of dependence on antibiotics. Biocontrol agents produced by bacteria isolated from apiarian sources seem promising and able to combine with an IPM strategy. The most significant findings of this study are the characterization of bacteriocin-like compounds (BLIS) obtained from two strains of Bacillus cereus isolated from honey. Both BLIS have a narrow activity range and highly inhibit the growth of Paenibacillus Larvae, the causal agent of American Foulbrood disease of honey bees.
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tetracycline resistance encoding plasmids from Paenibacillus Larvae the causal agent of american foulbrood disease isolated from commercial honeys
International Microbiology, 2014Co-Authors: Adriana Mónica Alippi, Ignacio E Leon, Ana Claudia LopezAbstract:Summary. Paenibacillus Larvae, the causal agent ofAmerican foulbrood disease in honeybees, acquires tetracycline-resis -tance via native plasmids carrying known tetracycline-resistance determinants. From three P. Larvae tetracycline-resistant strains isolated from honeys, 5-kb-circular plasmids with almost identical sequences, designated pPL373 in strain PL373, pPL374 in strain PL374, and pPL395 in strain PL395, were isolated. These plasmids were highly similar (99%) to small tetra-cycline-encoding plasmids (pMA67, pBHS24, pBSDMV46A, pDMV2, pSU1, pAST4, and pLS55) that replicate by the rolling circle mechanism. Nucleotide sequences comparisons showed that pPL373, pPL374, and pPL395 mainly differed from the previously reported P. Larvae plasmid pMA67 in the ori T region and mob genes. These differences suggest alternative mobili-zation and/or conjugation capacities. Plasmids pPL373, pPL374, and pPL395 were individually transferred by electroporation and stably maintained in tetracycline-susceptible
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Inhibition of the growth of Paenibacillus Larvae, the causal agent of American foulbrood of honeybees, by selected strains of aerobic spore-forming bacteria isolated from apiarian sources.
Journal of Invertebrate Pathology, 2006Co-Authors: Adriana Mónica Alippi, Francisco José ReynaldiAbstract:The bacterium Paenibacillus Larvae, the causative agent of American foulbrood disease of honeybee Larvae, occurs throughout the world and is found in many beekeeping areas of Argentina. The potential as biocontrol agents of antagonic aerobic spore-forming bacteria isolated from honey samples and other apiarian sources were evaluated. Each isolate was screened against one strain of Paenibacillus Larvae (ATCC 9545) by using a perpendicular streak technique. Ten randomly selected bacterial strains from the group that showed the best antagonistic effect to P. Larvae ATCC 9545 were selected for further study. These were identified as Bacillus subtilis (m351), B. pumilus (m350), B. licheniformis (m347), B. cereus (mv33), B. cereus (m387), B. cereus (m6c), B. megaterium (m404), Brevibacillus laterosporus (BLAT169), B. laterosporus (BLAT170), and B. laterosporus (BLAT171). The antagonistic strains were tested against 17 P. Larvae strains from different geographical origins by means of a spot test in wells. The analysis of variance and posterior comparison of means by Tukey method (P < 0.01) showed that the best antagonists were B. megaterium (m404), B. licheniformis (m347), B. cereus (m6c), B. cereus (mv33), and B. cereus (m387).
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in vitro and in vivo susceptibility of the honeybee bacterial pathogen Paenibacillus Larvae subsp Larvae to the antibiotic tylosin
Veterinary Microbiology, 2005Co-Authors: Adriana Mónica Alippi, Francisco José Reynaldi, Graciela Noemi Albo, Marisa Raquel De GiustiAbstract:The minimal inhibitory concentrations (MICs) of tylosin were determined to 67 strains of Paenibacillus Larvae subsp. Larvae, the causal agent of American Foulbrood (AFB) disease, from different geographical origins. MIC values obtained ranged from 0.0078 to 0.5 microg/ml. These very low values imply that no resistance to tylosin was found in any isolate of the Foulbrood pathogen. The measurement of diseased Larvae with AFB-clinical symptoms in three different field studies demonstrated that tylosin treatment could be effective in vivo. No negative effects in colonies were noted at any dosage rates or forms of application. These studies demonstrate that tylosin, as tartrate, can be used to treat AFB in honeybee colonies.
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a pcr based method that permits specific detection of Paenibacillus Larvae subsp Larvae the cause of american foulbrood of honey bees at the subspecies level
Letters in Applied Microbiology, 2004Co-Authors: Adriana Mónica Alippi, A C Lopez, O M AguilarAbstract:Aims: A reliable procedure for the identification of Paenibacillus Larvae subsp. Larvae, the causal agent of American Foulbrood disease of honey bees (Apis mellifera L.) based on the polymerase chain reaction (PCR) and subspecies – specific primers is described. Methods and Results: By using ERIC-PCR, an amplicon of ca 970 bp was found among P. l. Larvae strains but not in other closely related species. Based on the nucleotide sequence data of this amplicon, we designed the pair of oligonucleotides KAT 1 and KAT 2, which were assayed as primers in a PCR reaction. A PCR amplicon of the expected size ca 550 bp was only found in P. l. Larvae strains. Conclusions: This PCR assay provides a specific detection for P. l. Larvae. Significance and Impact of the Study: The developed PCR assay is highly specific because can differentiate Paenibacillus Larvae subsp. Larvae from the closely related Paenibacillus Larvae subsp. pulvifaciens. The technique can be directly used to detect presence or absence of P. l. Larvae spores in honey bee brood samples and contaminated honeys.
