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Sample records for bacterial plant pathogen

  1. Xylella Genomics and Bacterial Pathogenicity to Plants

    OpenAIRE

    Dow, J. M.; Daniels, M. J.

    2000-01-01

    Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics.

  2. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  3. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal

    OpenAIRE

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Lukasz L Stelinski; Pelz-Stelinski, Kirsten S.

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such mo...

  4. Ralstonia solanacearum, a widespread bacterial plant pathogen in the post-genomic era

    OpenAIRE

    Peeters, Nemo; Guidot, Alice; Vailleau, Fabienne; Valls i Matheu, Marc

    2013-01-01

    Ralstonia solanacearum is a soil-borne bacterium causing the widespread disease known as bacterial wilt. Ralstonia solanacearum is also the causal agent of Moko disease of banana and brown rot of potato. Since the last R. solanacearum pathogen profile was published 10 years ago, studies concerning this plant pathogen have taken a genomic and post-genomic direction. This was pioneered by the first sequenced and annotated genome for a major plant bacterial pathogen and followed by many more gen...

  5. Trophic network architecture of root-associated bacterial communities determines pathogen invasion and plant health

    OpenAIRE

    Wei, Zhong; Yang, Tianjie; Friman, Ville-Petri; Xu, Yangchun; Shen, Qirong; Jousset, Alexandre

    2015-01-01

    Host-associated bacterial communities can function as an important line of defence against pathogens in animals and plants. Empirical evidence and theoretical predictions suggest that species-rich communities are more resistant to pathogen invasions. Yet, the underlying mechanisms are unclear. Here, we experimentally test how the underlying resource competition networks of resident bacterial communities affect invasion resistance to the plant pathogen Ralstonia solanacearum in microcosms and ...

  6. Water relations in the interaction of foliar bacterial pathogens with plants.

    Science.gov (United States)

    Beattie, Gwyn A

    2011-01-01

    This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces. PMID:21438680

  7. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    Science.gov (United States)

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Stelinski, Lukasz L; Pelz-Stelinski, Kirsten S

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas) affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). CLas is the putative causal agent of huanglongbing (HLB), which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies. PMID:26083763

  8. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    Directory of Open Access Journals (Sweden)

    Xavier Martini

    Full Text Available The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama. CLas is the putative causal agent of huanglongbing (HLB, which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies.

  9. O antigen modulates insect vector acquisition of the bacterial plant pathogen Xylella fastidiosa.

    Science.gov (United States)

    Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline

    2015-12-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068

  10. Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Rajinder S Mann

    Full Text Available Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las, affects host preference behavior of its psyllid (Diaphorina citri Kuwayama vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of

  11. Virulence Program of a Bacterial Plant Pathogen: The Dickeya Model.

    Science.gov (United States)

    Reverchon, S; Muskhelisvili, G; Nasser, W

    2016-01-01

    The pectinolytic Dickeya spp. are Gram-negative bacteria causing severe disease in a wide range of plant species. Although the Dickeya genus was initially restricted to tropical and subtropical areas, two Dickeya species (D. dianthicola and D. solani) emerged recently in potato cultures in Europe. Soft-rot, the visible symptoms, is caused by plant cell wall degrading enzymes, mainly pectate lyases (Pels) that cleave the pectin polymer. However, an efficient colonization of the host requires many additional elements including early factors (eg, flagella, lipopolysaccharide, and exopolysaccharide) that allow adhesion of the bacteria and intermediate factors involved in adaptation to new growth conditions encountered in the host (eg, oxidative stress, iron starvation, and toxic compounds). To facilitate this adaptation, Dickeya have developed complex regulatory networks ensuring appropriate expression of virulence genes. This review presents recent advances in our understanding of the signals and genetic circuits impacting the expression of virulence determinants. Special attention is paid to integrated control of virulence functions by variations in the superhelical density of chromosomal DNA, and the global and specific regulators, making the regulation of Dickeya virulence an especially attractive model for those interested in relationships between the chromosomal dynamics and gene regulatory networks. PMID:27571692

  12. Analysis of bacterial communities and bacterial pathogens in a biogas plant by the combination of ethidium monoazide, PCR and Ion Torrent sequencing

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2014-01-01

    The present study investigated the changes of bacterial community composition including bacterial pathogens along a biogas plant, i.e. from the influent, to the biogas reactor and to the post-digester. The effects of post-digestion temperature and time on the changes of bacterial community...... had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion...... in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the...

  13. mADP-RTs: Versatile virulence factors from bacterial pathogens of plants and mammals

    Directory of Open Access Journals (Sweden)

    Lennart eWirthmueller

    2012-06-01

    Full Text Available Mono ADP-ribosyltransferases (mADP-RTs are a family of enzymes that cleave NAD+ and covalently attach the ADP-ribosyl moiety to target proteins. mADP-RTs are well established as important virulence factors of bacteria that infect mammals. Cholera toxin, pertussis toxin and diphteria toxin are three of the best-known examples of mADP-RTs. They modify host target proteins in order to promote infection and/or killing of the host cell. Despite low sequence similarity at the primary amino acid level, mADP-RTs share a conserved core catalytic fold and structural biology has made important contributions to elucidating how mADP-RTs modify mammalian host targets. Recently, mADP-RTs were shown to be present in plant pathogenic bacteria, suggesting that mADP-RTs are also important virulence factors of plant pathogens. Crystal structures of plant pathogenic bacterial mADP-RTs are also now available. Here we review the structure/function of mADP-RTs from pathogens of mammals and plants, highlighting both commonalities and differences.

  14. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    Science.gov (United States)

    De La Fuente, Leonardo; Parker, Jennifer K; Oliver, Jonathan E; Granger, Shea; Brannen, Phillip M; van Santen, Edzard; Cobine, Paul A

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  15. Community structure of actively growing bacterial populations in plant pathogen suppressive soil

    NARCIS (Netherlands)

    Hjort, K.; Lembke, A.; Speksnijder, A.G.C.L.; Smalla, K.; Jansson, J.K.

    2007-01-01

    The bacterial community in soil was screened by using various molecular approaches for bacterial populations that were activated upon addition of different supplements. Plasmodiophora brassicae spores, chitin, sodium acetate, and cabbage plants were added to activate specific bacterial populations a

  16. Investigating the Antimicrobial Bioactivity of Cyano bacterial Extracts on Some Plant and Human Pathogens

    International Nuclear Information System (INIS)

    The search for broad spectrum antimicrobial agents against microbial pathogens, as the available bioactive compounds, has decreasing efficacy and the multidrug resistance trait is spreading among pathogens. Accordingly, the study was carried out to investigate the antimicrobial bioactivity of extracts derived from a cyano bacterial strain from Egypt. The solvents used were diethyl ether, chloroform and methanol. The antimicrobial bioassay of the lipophilic fraction dissolved in diethyl ether of Synechococcus spp. (isolated from Wadi El-Natroun, Egypt) showed the highest broad spectrum bioactivity as it inhibited the growth of both plant and human pathogens. The extract was also effective on the filamentous plant pathogenic fungi Aspergillus flavus and Aspergillus niger. The effects of incubation periods, growth media and pH values on both growth and antimicrobial activity of Synechococcus spp. were investigated. Chu medium was the medium that gave the highest growth followed by BG11 medium then Oscillatoria medium and all these three media showed antibacterial activities but only BG11 showed both antibacterial and antifungal activities after 18 days of incubation. The pH value 10 proved to be the best for growth and antimicrobial activities of Synechococcus spp. in BG11 medium

  17. Isolation of bacterial fish pathogen Aeromonas hydrophila and therapeutic effects of medicinal plants on its invasion

    Directory of Open Access Journals (Sweden)

    Md. Tareq-Uz-Zaman

    2014-04-01

    Full Text Available Aeromonas hydrophila, a bacterial pathogen, was isolated form Pangasius hypophthalmus. For pathogenicity test, different doses were injected intramuscularly in Barbonymus gonionotus. Crude extracts were prepared from various parts Azadirachta indica, Curcuma longa, C. zedoaria, and Callotropis gigentia and applied to B. gonionotus for 7 days. Bath treatment was done up to their tolerance level and well ventilation was confirmed for aeration and 50% water was exchanged daily. Minimum inhibitory dose was detected as 7 mg/ml. High inhibitory effect was observed in case of A. indica and mixed extract of A. indica and C. gigentia. Both A. indica and C. gigentia showed the best result with 90-95% recovery of infected fish at a dose of 7 mg/l. C. zedoaria showed moderate to weak effect with 50-60% recovery at the same dose. The present study showed that medicinal plants would be an effective control measure against A. hydrophila.

  18. Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

    OpenAIRE

    Bhabesh Dutta; Ronald Gitaitis; Samuel Smith; David Langston

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same...

  19. Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

    The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.

  20. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    Directory of Open Access Journals (Sweden)

    Bhabesh Dutta

    Full Text Available The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6 colony forming units (CFUs/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion. Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating, respectively and they were not significantly different (P = 0.67. The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03. None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be

  1. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    Science.gov (United States)

    Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by

  2. Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

    Science.gov (United States)

    Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

  3. Effect of clove oil on plant pathogenic bacteria and bacterial wilt of tomato and geranium

    Science.gov (United States)

    We determined the antibacterial activity of clove oil against seven different genera of plant pathogenic bacteria including Gram-negative Agrobacterium tumefaciens, Erwinia carotovora pv. carotovora, Pseudomonas syringae pv. syringae, Ralstonia solanacearum, and Xanthomonas campestris pv. pelargonii...

  4. Heme uptake in bacterial pathogens

    OpenAIRE

    Contreras, Heidi; Chim, Nicholas; Credali, Alfredo; Goulding, Celia W.

    2014-01-01

    Iron is an essential nutrient for the survival of organisms. Bacterial pathogens possess specialized pathways to acquire heme from their human hosts. In this review, we present recent structural and biochemical data that provide mechanistic insights into several bacterial heme uptake pathways, encompassing the sequestration of heme from human hemoproteins to secreted or membrane-associated bacterial proteins, the transport of heme across bacterial membranes, and the degradation of heme within...

  5. Biological and genetic factors regulating natural competence in a bacterial plant pathogen.

    Science.gov (United States)

    Kung, Stephanie H; Almeida, Rodrigo P P

    2014-01-01

    For naturally competent bacteria, spatially structured growth can provide an environment for enhanced horizontal gene transfer through transformation and recombination. DNA is often present in the extracellular environment, such as in the extracellular matrix of biofilms, and the lysis of a single cell can result in high local DNA concentrations. Xylella fastidiosa is a naturally competent plant pathogen that typically lives in a surface-attached state, yet previous work characterizing the competence of this organism was conducted with planktonic cells in liquid environments. Here, we show that transformation and recombination efficiencies are two to three orders of magnitude higher for cells grown on solid compared with liquid media, with maximum recombination efficiencies of about 10(-3). Cells were highly competent throughout their exponential growth phase, with no significant change in recombination efficiencies until population growth rates began to slow. Mutations in type IV pili, competency-related, and cell-cell signalling genes significantly impacted the ability of X. fastidiosa to acquire and incorporate DNA. Because X. fastidiosa is highly competent when growing in a surface-attached state, as it does within its insect vectors and host plants, recombination of naturally transformed DNA could be a significant route by which horizontal gene transfer occurs in natural environments. PMID:24149707

  6. Plant Ribosomal Proteins, RPL12 and RPL19, Play a Role in Nonhost Disease Resistance against Bacterial Pathogens.

    Science.gov (United States)

    Nagaraj, Satish; Senthil-Kumar, Muthappa; Ramu, Vemanna S; Wang, Keri; Mysore, Kirankumar S

    2015-01-01

    Characterizing the molecular mechanism involved in nonhost disease resistance is important to understand the adaptations of plant-pathogen interactions. In this study, virus-induced gene silencing (VIGS)-based forward genetics screen was utilized to identify genes involved in nonhost resistance in Nicotiana benthamiana. Genes encoding ribosomal proteins, RPL12 and RPL19, were identified in the screening. These genes when silenced in N. benthamiana caused a delay in nonhost bacteria induced hypersensitive response (HR) with concurrent increase in nonhost bacterial multiplication. Arabidopsis mutants of AtRPL12 and AtRPL19 also compromised nonhost resistance. The studies on NbRPL12 and NbRPL19 double silenced plants suggested that both RPL12 and RPL19 act in the same pathway to confer nonhost resistance. Our work suggests a role for RPL12 and RPL19 in nonhost disease resistance in N. benthamiana and Arabidopsis. In addition, we show that these genes also play a minor role in basal resistance against virulent pathogens. PMID:26779226

  7. Plant Ribosomal Proteins, RPL12 and RPL19, Play a Role in Nonhost Disease Resistance against Bacterial Pathogens

    Science.gov (United States)

    Nagaraj, Satish; Senthil-Kumar, Muthappa; Ramu, Vemanna S.; Wang, Keri; Mysore, Kirankumar S.

    2016-01-01

    Characterizing the molecular mechanism involved in nonhost disease resistance is important to understand the adaptations of plant-pathogen interactions. In this study, virus-induced gene silencing (VIGS)-based forward genetics screen was utilized to identify genes involved in nonhost resistance in Nicotiana benthamiana. Genes encoding ribosomal proteins, RPL12 and RPL19, were identified in the screening. These genes when silenced in N. benthamiana caused a delay in nonhost bacteria induced hypersensitive response (HR) with concurrent increase in nonhost bacterial multiplication. Arabidopsis mutants of AtRPL12 and AtRPL19 also compromised nonhost resistance. The studies on NbRPL12 and NbRPL19 double silenced plants suggested that both RPL12 and RPL19 act in the same pathway to confer nonhost resistance. Our work suggests a role for RPL12 and RPL19 in nonhost disease resistance in N. benthamiana and Arabidopsis. In addition, we show that these genes also play a minor role in basal resistance against virulent pathogens. PMID:26779226

  8. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F.; Velvis, H.; Zachow, C.; Berg, G.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4 lysozyme

  9. Pathogen Phytosensing: Plants to Report Plant Pathogens

    Directory of Open Access Journals (Sweden)

    C. Neal Stewart

    2008-04-01

    Full Text Available Real-time systems that provide evidence of pathogen contamination in crops can be an important new line of early defense in agricultural centers. Plants possess defense mechanisms to protect against pathogen attack. Inducible plant defense is controlled by signal transduction pathways, inducible promoters and cis-regulatory elements corresponding to key genes involved in defense, and pathogen-specific responses. Identified inducible promoters and cis-acting elements could be utilized in plant sentinels, or ‘phytosensors’, by fusing these to reporter genes to produce plants with altered phenotypes in response to the presence of pathogens. Here, we have employed cis-acting elements from promoter regions of pathogen inducible genes as well as those responsive to the plant defense signal molecules salicylic acid, jasmonic acid, and ethylene. Synthetic promoters were constructed by combining various regulatory elements supplemented with the enhancer elements from the Cauliflower mosaic virus (CaMV 35S promoter to increase basal level of the GUS expression. The inducibility of each synthetic promoter was first assessed in transient expression assays using Arabidopsis thaliana protoplasts and then examined for efficacy in stably transgenic Arabidopsis and tobacco plants. Histochemical and fluorometric GUS expression analyses showed that both transgenic Arabidopsis and tobacco plants responded to elicitor and phytohormone treatments with increased GUS expression when compared to untreated plants. Pathogen-inducible phytosensor studies were initiated by analyzing the sensitivity of the synthetic promoters against virus infection. Transgenic tobacco plants infected with Alfalfa mosaic virus showed an increase in GUS expression when compared to mock-inoculated control plants, whereas Tobacco mosaic virus infection caused no changes in GUS expression. Further research, using these transgenic plants against a range of different

  10. A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry

    Directory of Open Access Journals (Sweden)

    Sayed Muhammed

    2004-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. Presentation of the hypothesis The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a PNP-like protein. We hypothesise that this bacterial protein can alter plant cell homeostasis and thus is likely to represent an example of molecular mimicry that enables the pathogen to manipulate plant responses in order to bring about conditions favourable to the pathogen such as the induced plant tissue hyper-hydration seen in the wet edged lesions associated with Xanthomonas axonopodis infection. Testing the hypothesis We found a Xanthomonas axonopodis PNP-like protein that shares significant sequence similarity and identical domain organisation with PNPs. We also observed a significant excess of conserved residues between the two proteins within the domain previously identified as being sufficient to induce biological activity. Structural modelling predicts identical six stranded double-psi β barrel folds for both proteins thus supporting the hypothesis of similar modes of action. No significant similarity between the Xanthomonas axonopodis protein and other bacterial proteins from GenBank was found. Sequence similarity of the Xanthomonas axonopodis PNP-like protein with the Arabidopsis thaliana PNP (AtPNP-A, shared domain organisation and incongruent phylogeny suggest that the PNP-gene may have been acquired by the bacteria in an ancient lateral gene transfer event. Finally, activity of a recombinant Xanthomonas axonopodis protein in plant tissue and changes in symptoms induced by a Xanthomonas axonopodis mutant with a knocked-out PNP-like gene will be experimental proof of molecular mimicry

  11. Proteomics of foodborne bacterial pathogens

    Science.gov (United States)

    This chapter focuses on recent research on foodborne bacterial pathogens that use mass spectrometry-based proteomic techniques as well as protein microarrays. Mass spectrometry ionization techniques (e.g. electrospray ionization and matrix-assisted laser desorption/ionization), analyzers (e.g. ion ...

  12. Assessment of the relevance of the antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine from Pantoea agglomerans biological control strains against bacterial plant pathogens.

    Science.gov (United States)

    Sammer, Ulrike F; Reiher, Katharina; Spiteller, Dieter; Wensing, Annette; Völksch, Beate

    2012-12-01

    The epiphyte Pantoea agglomerans 48b/90 (Pa48b) is a promising biocontrol strain against economically important bacterial pathogens such as Erwinia amylovora. Strain Pa48b produces the broad-spectrum antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine (APV) in a temperature-dependent manner. An APV-negative mutant still suppressed the E. amylovora population and fire blight disease symptoms in apple blossom experiments under greenhouse conditions, but was inferior to the Pa48b wild-type indicating the influence of APV in the antagonism. In plant experiments with the soybean pathogen Pseudomonas syringae pv. glycinea both, Pa48b and the APV-negative mutant, successfully suppressed the pathogen. Our results demonstrate that the P. agglomerans strain Pa48b is an efficient biocontrol organism against plant pathogens, and we prove its ability for fast colonization of plant surfaces over a wide temperature range. PMID:23233458

  13. Zoosporic plant pathogens produce bacterial autoinducer-2 that affects Vibrio harveyi quorum sensing

    Science.gov (United States)

    Kong, Ping; Lee, Bobby W.K.; Zhou, Zhaohui Sunny; Hong, Chuanxue

    2009-01-01

    The frequent co-isolation of bacteria with Phytophthora and Pythium species suggests possible interspecies communication. Zoospore free fluids (ZFF) from bacteria-free and nutrient-depleted zoospore suspensions were examined to investigate production of autoinducer-2 (AI-2), a bacterial interspecies signal molecule, by zoosporic oomycetes. ZFF from P. nicotianae, P. sojae and Py. aphanidermatum triggered luminescence of Vibrio harveyi AI-2 reporter, indicating the presence of AI-2 in zoospore extracellular products and the potential of cross-kingdom communication between oomycetes and bacteria. Production of AI-2 by zoospores was confirmed by chemical assays. These results provide new insight into the physiology and ecology of oomycetes. PMID:20002192

  14. Top 10 plant pathogenic bacteria in molecular plant pathology

    OpenAIRE

    Mansfield, John; Genin, Stephane; Magori, Shimpei; Citovsky, Vitaly; Sriariyanum, Malinee; Ronald, Pamela; Dow, Max; Verdier, Valérie; Beer, Steven V.; Marcos A. MACHADO; Toth, Ian; Salmond, George; Foster, Gary D.

    2012-01-01

    Many plant bacteriologists, if not all, feel that their particular microbe should appear in any list of the most important bacterial plant pathogens. However, to our knowledge, no such list exists. The aim of this review was to survey all bacterial pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate the bacterial pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 458 votes from the internation...

  15. Genomic Basis of Plant Pathogen Suppression by Biocontrol Pseudomonas Species

    Science.gov (United States)

    Various plant commensal bacterial species, which naturally colonize the plant rhizosphere, are able to suppress fungal, bacterial, viral and even insect plant pathogens. These biocontrol activities are elicited primarily through the production of secreted exoenzymes and secondary metabolites that ma...

  16. Plant pathogen resistance

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, Jean T.; Jung, Ho Won; Tschaplinski, Timothy

    2015-10-20

    Azelaic acid or its derivatives or analogs induce a robust and a speedier defense response against pathogens in plants. Azelaic acid treatment alone does not induce many of the known defense-related genes but activates a plant's defense signaling upon pathogen exposure.

  17. Bacteriophages for detection of bacterial pathogens

    International Nuclear Information System (INIS)

    The G. Eliava Institute of Bacteriophages, Microbiology and Virology (Tbilisi, Georgia) is one of the most famous institutions focused on bacteriophage research for the elaboration of appropriate phage methodologies for human and animal protection. The main direction of the institute is the study and production of bacteriophages against intestinal disorders (dysentery, typhoid, intesti) and purulent-septic infections (staphylococcus, streptococcus, pyophage, etc.). These preparations were successfully introduced during the Soviet era, and for decades were used throughout the former Soviet Union and in other Socialist countries for the treatment, prophylaxis, and diagnosis of various infectious diseases, including those caused by antibiotic-resistant bacterial strains. Bacteriophages were widely used for identifying and detecting infections caused by the most dangerous pathogens and causative agents of epidemiological outbreaks. The specific topic of this presentation is the phage typing of bacterial species, which can be an important method for epidemiological diagnostics. Together with different genetic methodologies - such as PCR-based methods, PFGE, plasmid fingerprinting, and ribosomal typing - phage typing is one method for identifying bacterial pathogens. The method has a high percentage of determination of phage types, high specificity of reaction, and is easy for interpretation and use by health workers. Phage typing was applied for inter-species differentiation of different species of Salmonella, S. typhi, Brucella spp, Staphylococcus aureus, E. col,i Clostridium deficile, Vibrio cholerae, Yersinia pestis, Yersinia enterocolitica, Lysteria monocytogenes, Clostridium perfringens, Clostridium tetani, plant pathogens, and other bacterial pathogens. In addition to addressing the utility and efficacy of phage typing, the paper will discuss the isolation and selection of diagnostic typing phages for interspecies differentiation of pathogens that is necessary

  18. Insights from Genomics into Bacterial Pathogen Populations

    OpenAIRE

    Wilson, DJ

    2012-01-01

    Bacterial pathogens impose a heavy burden of disease on human populations worldwide. The gravest threats are posed by highly virulent respiratory pathogens, enteric pathogens, and HIV-associated infections. Tuberculosis alone is responsible for the deaths of 1.5 million people annually. Treatment options for bacterial pathogens are being steadily eroded by the evolution and spread of drug resistance. However, population-level whole genome sequencing offers new hope in the fight against pathog...

  19. Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Geun Cheol eSong

    2015-10-01

    Full Text Available 3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 M and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR gene expression levels associated with defense signaling through SA, JA, and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved salicylic acid (SA and jasmonic acid (JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

  20. Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions

    Directory of Open Access Journals (Sweden)

    Choong-Min Ryu

    2013-05-01

    Full Text Available Systemic acquired resistance (SAR is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields.

  1. A Single-Step Purification of Cauliflower Lysozyme and Its Dual Role Against Bacterial and Fungal Plant Pathogens.

    Science.gov (United States)

    Manikandan, Muthu; Balasubramaniam, R; Chun, Se-Chul

    2015-09-01

    A novel lysozyme from cauliflower was purified in a single step, for the first time, using Sephadex G100 column chromatography. The purified lysozyme exhibited a homogenized single band in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and its molecular mass was calculated to be 22.0 kDa. The purified lysozyme showed activity between 30 to 60 °C with 40 °C as the optimum temperature for its maximal activity. Although the purified lysozyme was functional at pH ranges between 3.0 and 9.0, the optimum pH for the enzyme activity was 8.0. By Michaelis-Menten equation, the threshold substrate concentration for the optimal enzyme activity was calculated to be 133.0 μg. The purified lysozyme showed extraordinary activity against plant pathogenic bacteria and fungi. At 10-μg concentrations, it inhibited the growth of plant pathogenic bacteria such as Pseudomonas syringae, Xanthomonas campestris, and Erwinia carotovora exhibiting 4.28, 5.90, and 3.88-fold inhibition, respectively. Further, it also completely inhibited the conidial germination of Archemonium obclavatum and, to a very large extent, other fungal species such as Fusarium solani (79.3 %), Leptosphaeria maculans (88.6 %), Botrytis cinera (73.3 %), Curvularia lunata (68 %), Rhizoctonia solani (79.6 %), and Alternaria alternata (83.6 %). PMID:26208688

  2. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway.

    Science.gov (United States)

    Yang, Wei; Xu, Xiaonan; Li, Yang; Wang, Yingzi; Li, Ming; Wang, Yong; Ding, Xinhua; Chu, Zhaohui

    2016-01-01

    Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato strain DC3000 in rice, tobacco and Arabidopsis thaliana respectively. While they were normally propagated on the cultural medium supplemented with 2 mM rutin for those pathogenic bacteria. The enhanced resistance was associated with primed expression of several pathogenesis-related genes. We also demonstrated that the rutin-mediated priming resistance was attenuated in npr1, eds1, eds5, pad4-1, ndr1 mutants, and NahG transgenic Arabidopsis plant, while not in either snc1-11, ein2-5 or jar1 mutants. We concluded that the rutin-priming defense signal was modulated by the salicylic acid (SA)-dependent pathway from an early stage upstream of NDR1 and EDS1. PMID:26751786

  3. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway.

    Directory of Open Access Journals (Sweden)

    Wei Yang

    Full Text Available Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato strain DC3000 in rice, tobacco and Arabidopsis thaliana respectively. While they were normally propagated on the cultural medium supplemented with 2 mM rutin for those pathogenic bacteria. The enhanced resistance was associated with primed expression of several pathogenesis-related genes. We also demonstrated that the rutin-mediated priming resistance was attenuated in npr1, eds1, eds5, pad4-1, ndr1 mutants, and NahG transgenic Arabidopsis plant, while not in either snc1-11, ein2-5 or jar1 mutants. We concluded that the rutin-priming defense signal was modulated by the salicylic acid (SA-dependent pathway from an early stage upstream of NDR1 and EDS1.

  4. In vitro interaction of certain antimicrobial agents in combination with plant extracts against some pathogenic bacterial strains

    Institute of Scientific and Technical Information of China (English)

    Kalpna Rakholiya; Sumitra Chanda

    2012-01-01

    Objective: To evaluate the in vitro interaction between methanolic extracts of Terminalia catappa (Combretaceae) (T. catappa) and Carica papaya (caricaceae) (C. papaya) leaves and certain known antimicrobial drugs like penicillin G (P), ampicillin (AMP), amoxyclav (AMC), cephalothin (CEP), polymyxin B (PB), rifampicin (RIF), amikacin (AK), nilidixic acid (NA), gentamicin (GEN), chloramphenicol (C), ofloxacin (OF) against five Gram positive and five Gram negative bacteria.Methods:Evaluation of synergy interaction between plant extracts and antimicrobial agents was carried out using disc diffusion method. Results: The results of this study showed that there is an increased activity in case of combination of methanolic plant extracts and test antimicrobial agents. The more potent result was that the synergism between methanolic extract of C. papaya and antibiotics showed highest and strong synergistic effect against tested bacterial strains;though methanolic extract of C. papaya alone was not showing any antibacterial activity.Conclusions:These results indicate that combination between plant extract and the antibiotics could be useful in fighting emerging drug-resistance microorganisms.

  5. In vitro interaction of certain antimicrobial agents in combination with plant extracts against some pathogenic bacterial strains

    Institute of Scientific and Technical Information of China (English)

    Kalpna Rakholiya; Sumitra Chanda

    2012-01-01

    Objective: To evaluate the in vitro interaction between methanolic extracts of Terminalia catappa (T. catappa) (Combretaceae) and Carica papaya (C. papaya) (caricaceae) leaves and certain known antimicrobial drugs like penicillin G (P), ampicillin (AMP), amoxyclav (AMC), cephalothin (CEP), polymyxin B (PB), rifampicin (RIF), amikacin (AK), nilidixic acid (NA), gentamicin (GEN), chloramphenicol (C), ofloxacin (OF) against five Gram positive and five Gram negative bacteria. Methods: Evaluation of synergy interaction between plant extracts and antimicrobial agents was carried out using disc diffusion method. Results: The results of this study showed that there is an increased activity in case of combination of methanolic plant extracts and test antimicrobial agents. The more potent result was that the synergism between methanolic extract of C. papaya and antibiotics showed highest and strong synergistic effect against tested bacterial strains;though methanolic extract of C. papaya alone was not showing any antibacterial activity. Conclusions: These results indicate that combination between plant extract and the antibiotics could be useful in fighting emerging drug-resistance microorganisms.

  6. Bats and bacterial pathogens: a review.

    Science.gov (United States)

    Mühldorfer, K

    2013-02-01

    The occurrence of emerging infectious diseases and their relevance to human health has increased the interest in bats as potential reservoir hosts and vectors of zoonotic pathogens. But while previous and ongoing research activities predominantly focused on viral agents, the prevalence of pathogenic bacteria in bats and their impact on bat mortality have largely neglected. Enteric pathogens found in bats are often considered to originate from the bats' diet and foraging habitats, despite the fact that little is known about the actual ecological context or even transmission cycles involving bats, humans and other animals like pets and livestock. For some bacterial pathogens common in human and animal diseases (e.g. Pasteurella, Salmonella, Escherichia and Yersinia spp.), the pathogenic potential has been confirmed for bats. Other bacterial pathogens (e.g. Bartonella, Borrelia and Leptospira spp.) provide evidence for novel species that seem to be specific for bat hosts but might also be of disease importance in humans and other animals. The purpose of this review is to summarize the current knowledge of bacterial pathogens identified in bats and to consider factors that might influence the exposure and susceptibility of bats to bacterial infection but could also affect bacterial transmission rates between bats, humans and other animals. PMID:22862791

  7. A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry

    OpenAIRE

    Sayed Muhammed; Seoighe Cathal; Nembaware Victoria; Gehring Chris

    2004-01-01

    Abstract Background Plant natriuretic peptides (PNPs) are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. Presentation of the hypothesis The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a PNP-like protein. We hypothesise that this ...

  8. Within-host evolution of bacterial pathogens.

    OpenAIRE

    Didelot, X.; Walker, AS; Peto, TE; Crook, DW; Wilson, DJ

    2016-01-01

    Whole-genome sequencing has opened the way for investigating the dynamics and genomic evolution of bacterial pathogens during the colonization and infection of humans. The application of this technology to the longitudinal study of adaptation in an infected host - in particular, the evolution of drug resistance and host adaptation in patients who are chronically infected with opportunistic pathogens - has revealed remarkable patterns of convergent evolution, suggestive of an inherent repeatab...

  9. Microbial minimalism: genome reduction in bacterial pathogens.

    Science.gov (United States)

    Moran, Nancy A

    2002-03-01

    When bacterial lineages make the transition from free-living or facultatively parasitic life cycles to permanent associations with hosts, they undergo a major loss of genes and DNA. Complete genome sequences are providing an understanding of how extreme genome reduction affects evolutionary directions and metabolic capabilities of obligate pathogens and symbionts. PMID:11893328

  10. Lactoferrin-derived resistance against plant pathogens in transgenic plants.

    Science.gov (United States)

    Lakshman, Dilip K; Natarajan, Savithiry; Mandal, Sudhamoy; Mitra, Amitava

    2013-12-01

    Lactoferrin (LF) is a ubiquitous cationic iron-binding milk glycoprotein that contributes to nutrition and exerts a broad-spectrum primary defense against bacteria, fungi, protozoa, and viruses in mammals. These qualities make lactoferrin protein and its antimicrobial motifs highly desirable candidates to be incorporated in plants to impart broad-based resistance against plant pathogens or to economically produce them in bulk quantities for pharmaceutical and nutritional purposes. This study introduced bovine LF (BLF) gene into tobacco ( Nicotiana tabacum var. Xanthi), Arabidopsis ( A. thaliana ) and wheat ( Triticum aestivum ) via Agrobacterium -mediated plant transformation. Transgenic plants or detached leaves exhibited high levels of resistance against the damping-off causing fungal pathogen Rhizoctonia solani and the head blight causing fungal pathogen Fusarium graminearum . LF also imparted resistance to tomato plants against a bacterial pathogen, Ralstonia solanacearum . Similarly, other researchers demonstrated expression of LF and LF-mediated high-quality resistance to several other aggressive fungal and bacterial plant pathogens in transgenic plants and against viral pathogens by foliar applications of LF or its derivatives. Taken together, these studies demonstrated the effectiveness of LF for improving crop quality and its biopharming potentials for pharmaceautical and nutritional applications. PMID:23889215

  11. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway

    OpenAIRE

    Yang, Wei; Xu, Xiaonan; Li, Yang; Wang, Yingzi; Li, Ming; Wang, Yong; Ding, Xinhua; Chu, Zhaohui

    2016-01-01

    Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato...

  12. Burkholderia rhizoxinica sp. nov. and Burkholderia endofungorum sp. nov., bacterial endosymbionts of the plant-pathogenic fungus Rhizopus microsporus.

    Science.gov (United States)

    Partida-Martinez, Laila P; Groth, Ingrid; Schmitt, Imke; Richter, Walter; Roth, Martin; Hertweck, Christian

    2007-11-01

    Several strains of the fungus Rhizopus microsporus harbour endosymbiotic bacteria for the production of the causal agent of rice seedling blight, rhizoxin, and the toxic cyclopeptide rhizonin. R. microsporus and isolated endobacteria were selected for freeze-fracture electron microscopy, which allowed visualization of bacterial cells within the fungal cytosol by their two parallel-running envelope membranes and by the fine structure of the lipopolysaccharide layer of the outer membrane. Two representatives of bacterial endosymbionts were chosen for phylogenetic analyses on the basis of full 16S rRNA gene sequences, which revealed that the novel fungal endosymbionts formed a monophyletic group within the genus Burkholderia. Inter-sequence similarities ranged from 98.94 to 100%, and sequence similarities to members of the Burkholderia pseudomallei group, the closest neighbours, were 96.74-97.38%. In addition, the bacterial strains were distinguished from their phylogenetic neighbours by their fatty acid profiles and other biochemical characteristics. The phylogenetic studies based on 16S rRNA gene sequence data, together with conclusive DNA-DNA reassociation experiments, strongly support the proposal that these strains represent two novel species within the genus Burkholderia, for which the names Burkholderia rhizoxinica sp. nov. (type strain, HKI 454T=DSM 19002T=CIP 109453T) and Burkholderia endofungorum sp. nov. (type strain, HKI 456T=DSM 19003T=CIP 109454T) are proposed. PMID:17978222

  13. Emerging bacterial pathogens: the past and beyond.

    Science.gov (United States)

    Vouga, M; Greub, G

    2016-01-01

    Since the 1950s, medical communities have been facing with emerging and reemerging infectious diseases, and emerging pathogens are now considered to be a major microbiologic public health threat. In this review, we focus on bacterial emerging diseases and explore factors involved in their emergence as well as future challenges. We identified 26 major emerging and reemerging infectious diseases of bacterial origin; most of them originated either from an animal and are considered to be zoonoses or from water sources. Major contributing factors in the emergence of these bacterial infections are: (1) development of new diagnostic tools, such as improvements in culture methods, development of molecular techniques and implementation of mass spectrometry in microbiology; (2) increase in human exposure to bacterial pathogens as a result of sociodemographic and environmental changes; and (3) emergence of more virulent bacterial strains and opportunistic infections, especially affecting immunocompromised populations. A precise definition of their implications in human disease is challenging and requires the comprehensive integration of microbiological, clinical and epidemiologic aspects as well as the use of experimental models. It is now urgent to allocate financial resources to gather international data to provide a better understanding of the clinical relevance of these waterborne and zoonotic emerging diseases. PMID:26493844

  14. Emerging food pathogens and bacterial toxins.

    Science.gov (United States)

    Bielecki, Jacek

    2003-01-01

    Many different foodborne diseases have been described. For example, Shigella bacteria, hepatitis A virus and Norwalk virus were shown as a unwashed hands microorganisms, but pathogen Campylobacter and Escherichia coli were named as raw and undercooked meat and poultry or raw milk and untreated water born bacteria. However, two of them: Listeria monocytogenes and Yersinia enterocolitica are known as growing at refrigerator temperatures. Essential virulence determinants of Listeria monocytogenes pathogenicity are well known as a bacterial toxins. Basic molecular mechanisms of pathogenicity depending from these toxins were presented. It was shown that other bacterial toxins may act as very danger food poisoning substances. This is why elimination of pathogenic microorganisms from foods is an obvious solution in some food processes, however this approach is not practical or even desirable in many processes. Thus, risk assessment and microbial monitoring will continue to play important roles in ensuring food safety. Some technological advances have the capability of delivering detection systems that can not only monitor pathogenic microorganisms, but also entire microbial populations in the food matrix. PMID:15058810

  15. Host-pathogen interactions in bacterial meningitis.

    Science.gov (United States)

    Doran, Kelly S; Fulde, Marcus; Gratz, Nina; Kim, Brandon J; Nau, Roland; Prasadarao, Nemani; Schubert-Unkmeir, Alexandra; Tuomanen, Elaine I; Valentin-Weigand, Peter

    2016-02-01

    Bacterial meningitis is a devastating disease occurring worldwide with up to half of the survivors left with permanent neurological sequelae. Due to intrinsic properties of the meningeal pathogens and the host responses they induce, infection can cause relatively specific lesions and clinical syndromes that result from interference with the function of the affected nervous system tissue. Pathogenesis is based on complex host-pathogen interactions, some of which are specific for certain bacteria, whereas others are shared among different pathogens. In this review, we summarize the recent progress made in understanding the molecular and cellular events involved in these interactions. We focus on selected major pathogens, Streptococcus pneumonia, S. agalactiae (Group B Streptococcus), Neisseria meningitidis, and Escherichia coli K1, and also include a neglected zoonotic pathogen, Streptococcus suis. These neuroinvasive pathogens represent common themes of host-pathogen interactions, such as colonization and invasion of mucosal barriers, survival in the blood stream, entry into the central nervous system by translocation of the blood-brain and blood-cerebrospinal fluid barrier, and induction of meningeal inflammation, affecting pia mater, the arachnoid and subarachnoid spaces. PMID:26744349

  16. Lipid transfer proteins (nsLTPs) from barley and maize leaves are potent inhibitors of bacterial and fungal plant pathogens

    OpenAIRE

    Molina Fernández, Antonio; Segura, Ana; García Olmedo, Francisco

    1993-01-01

    Four homogeneous proteins (Cw18, Cw20, Cw21, Cw22) were isolated from etiolated barley leaves by extraction of the insoluble pellet from a Tris-HCl (pH 7.5) homogenate with 1.5 M LiCl and fractionation by reverse-phase high-performance liquid chromatography. All 4 proteins inhibited growth of the pathogen Clavibacter michiganensis subsp. sepedonicus (EC50S = 1−3 × 10−7 M) and had closely related N-terminal amino acid sequences. The complete amino acid sequences of proteins Cw18 and Cw21 were ...

  17. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

    Full Text Available Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed.

  18. Formaldehyde Stress Responses in Bacterial Pathogens.

    Science.gov (United States)

    Chen, Nathan H; Djoko, Karrera Y; Veyrier, Frédéric J; McEwan, Alastair G

    2016-01-01

    Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR, and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed. PMID:26973631

  19. Bacterial Modulation of Plant Ethylene Levels.

    Science.gov (United States)

    Gamalero, Elisa; Glick, Bernard R

    2015-09-01

    A focus on the mechanisms by which ACC deaminase-containing bacteria facilitate plant growth.Bacteria that produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, when present either on the surface of plant roots (rhizospheric) or within plant tissues (endophytic), play an active role in modulating ethylene levels in plants. This enzyme activity facilitates plant growth especially in the presence of various environmental stresses. Thus, plant growth-promoting bacteria that express ACC deaminase activity protect plants from growth inhibition by flooding and anoxia, drought, high salt, the presence of fungal and bacterial pathogens, nematodes, and the presence of metals and organic contaminants. Bacteria that express ACC deaminase activity also decrease the rate of flower wilting, promote the rooting of cuttings, and facilitate the nodulation of legumes. Here, the mechanisms behind bacterial ACC deaminase facilitation of plant growth and development are discussed, and numerous examples of the use of bacteria with this activity are summarized. PMID:25897004

  20. The intrinsic resistome of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    JoseLMartinez

    2013-04-01

    Full Text Available Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally a low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyse recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.

  1. Population genomic analysis of a bacterial plant pathogen: novel insight into the origin of Pierce's disease of grapevine in the U.S.

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    Leonard Nunney

    Full Text Available Invasive diseases present an increasing problem worldwide; however, genomic techniques are now available to investigate the timing and geographical origin of such introductions. We employed genomic techniques to demonstrate that the bacterial pathogen causing Pierce's disease of grapevine (PD is not native to the US as previously assumed, but descended from a single genotype introduced from Central America. PD has posed a serious threat to the US wine industry ever since its first outbreak in Anaheim, California in the 1880s and continues to inhibit grape cultivation in a large area of the country. It is caused by infection of xylem vessels by the bacterium Xylella fastidiosa subsp. fastidiosa, a genetically distinct subspecies at least 15,000 years old. We present five independent kinds of evidence that strongly support our invasion hypothesis: 1 a genome-wide lack of genetic variability in X. fastidiosa subsp. fastidiosa found in the US, consistent with a recent common ancestor; 2 evidence for historical allopatry of the North American subspecies X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa; 3 evidence that X. fastidiosa subsp. fastidiosa evolved in a more tropical climate than X. fastidiosa subsp. multiplex; 4 much greater genetic variability in the proposed source population in Central America, variation within which the US genotypes are phylogenetically nested; and 5 the circumstantial evidence of importation of known hosts (coffee plants from Central America directly into southern California just prior to the first known outbreak of the disease. The lack of genetic variation in X. fastidiosa subsp. fastidiosa in the US suggests that preventing additional introductions is important since new genetic variation may undermine PD control measures, or may lead to infection of other crop plants through the creation of novel genotypes via inter-subspecific recombination. In general, geographically mixing of previously

  2. Quorum sensing in plant-pathogenic bacteria.

    Science.gov (United States)

    Von Bodman, Susanne B; Bauer, W Dietz; Coplin, David L

    2003-01-01

    Quorum sensing (QS) allows bacteria to assess their local population density and/or physical confinement via the secretion and detection of small, diffusible signal molecules. This review describes how phytopathogenic bacteria have incorporated QS mechanisms into complex regulatory cascades that control genes for pathogenicity and colonization of host surfaces. Traits regulated by QS include the production of extracellular polysaccharides, degradative enzymes, antibiotics, siderophores, and pigments, as well as Hrp protein secretion, Ti plasmid transfer, motility, biofilm formation, and epiphytic fitness. Since QS regulatory systems are often required for pathogenesis, interference with QS signaling may offer a means of controlling bacterial diseases of plants. Several bacterial pathogens of plants that have been intensively studied and have revealed information of both fundamental and practical importance are reviewed here: Agrobacterium tumefaciens, Pantoea stewartii, Erwinia carotovora, Ralstonia solanacearum, Pseudomonas syringae, Pseudomonas aeruginosa, and Xanthomonas campestris. PMID:12730390

  3. RNA-Seq for Plant Pathogenic Bacteria

    OpenAIRE

    Kimbrel, Jeffrey A.; Yanming Di; Cumbie, Jason S.; Chang, Jeff H.

    2011-01-01

    The throughput and single-base resolution of RNA-Sequencing (RNA-Seq) have contributed to a dramatic change in transcriptomic-based inquiries and resulted in many new insights into the complexities of bacterial transcriptomes. RNA-Seq could contribute to similar advances in our understanding of plant pathogenic bacteria but it is still a technology under development with limitations and unknowns that need to be considered. Here, we review some new developments for RNA-Seq and highlight recent...

  4. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  5. The plant pathogenic fungus Gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain Pseudomonas fluorescens Pf29Arp.

    Science.gov (United States)

    Barret, M; Frey-Klett, P; Boutin, M; Guillerm-Erckelboudt, A-Y; Martin, F; Guillot, L; Sarniguet, A

    2009-01-01

    In soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. Direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. An in vitro confrontation bioassay between the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) and the biocontrol bacterial strain Pseudomonas fluorescens Pf29Arp was set up to analyse bacterial transcriptional changes induced by the fungal mycelium at three time-points of the interaction before cell contact and up until contact. For this, a Pf29Arp shotgun DNA microarray was constructed. Specifity of Ggt effect was assessed in comparison with one of two other filamentous fungi, Laccaria bicolor and Magnaporthe grisea. During a commensal interaction, Ggt increased the growth rate of Pf29Arp. Before contact, Ggt induced bacterial genes involved in mycelium colonization. At contact, genes encoding protein of stress response and a patatin-like protein were up-regulated. Among all the bacterial genes identified, xseB was specifically up-regulated at contact by Ggt but down-regulated by the other fungi. Data showed that the bacterium sensed the presence of the fungus early, but the main gene alteration occurred during bacterial-fungal cell contact. PMID:19121038

  6. [Population genetics of plant pathogens].

    Science.gov (United States)

    Zhu, Wen; Zhan, Jia-Sui

    2012-02-01

    Comparing to natural ecosystems, the evolution of plant pathogens in agricultural ecosystems is generally faster due to high-density monocultures, large-scale application of agrochemicals, and international trade in agricultural products. Knowledge of the population genetics and evolutionary biology of plant pathogens is necessary to understand disease epidemiology, effectively breed and use resistant cultivars, and control plant diseases. In this article, we outlined the aims of population genetic studies in plant pathogens, discuss contributions of five evolutionary forces (i.e., mutation, gene flow, recombination, random genetic drift, and natural selection) to origin, maintenance, and distribution of genetic variation in time and space, and gave an overview of current research status in this field. PMID:22382057

  7. Assessment of the relevance of the antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine from Pantoea agglomerans biological control strains against bacterial plant pathogens

    OpenAIRE

    Sammer, Ulrike F.; Reiher, Katharina; Spiteller, Dieter; Wensing, Annette; Völksch, Beate

    2012-01-01

    The epiphyte Pantoea agglomerans 48b/90 (Pa48b) is a promising biocontrol strain against economically important bacterial pathogens such as Erwinia amylovora. Strain Pa48b produces the broad-spectrum antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine (APV) in a temperature-dependent manner. An APV-negative mutant still suppressed the E. amylovora population and fire blight disease symptoms in apple blossom experiments under greenhouse conditions, but was inferior to the Pa48b w...

  8. Meeting report: Adaptation and communication of bacterial pathogens.

    Science.gov (United States)

    Aussel, Laurent; Beuzón, Carmen R; Cascales, Eric

    2016-05-18

    Bacteria usually live in complex environments, sharing niche and resources with other bacterial species, unicellular eukaryotic cells or complex organisms. Thus, they have evolved mechanisms to communicate, to compete and to adapt to changing environment as diverse as human tissues, animals or plants. Understanding the molecular mechanisms underlying these adaptation processes is therefore of primary importance for epidemiology and human health protection, and was the focus of a Current Trends in Biomedicine workshop organized by the International University of Andalucia in late October 2015 in Baeza (Spain). The topic was covered by complementary sessions: (i) interbacterial communication and competition that enable a better access to nutrients or a more efficient colonization of the ecological niche, (ii) adaptation of intracellular pathogens to their host, focusing on metabolic pathways, adaptive mechanisms and populational heterogeneity, and (iii) adaptation of animal and plant pathogens as well as plant-associated bacteria to a plant niche. This workshop emphasized the broad repertoire of mechanisms and factors bacteria have evolved to become efficient pathogens. PMID:26890494

  9. Ecological niche of plant pathogens

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2011-02-01

    Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important for the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread.

  10. Ecological niche of plant pathogens

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2011-06-01

    Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread. 

  11. Pathotypes of Bacterial Spot Pathogen Infecting Capsicum Peppers in Korea

    OpenAIRE

    Wai, Khin Pa Pa; Siddique, Muhammad Irfan; Mo, Hwang-Sung; Yoo, Hee Ju; Byeon, Si-Eun; Jegal, Yoonhyuk; Mekuriaw, Alebel A.; Kim, Byung-Soo

    2015-01-01

    Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp.) collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum) pepper plants carrying Bs1 , Bs2 and Bs3 , and PI235047 (C. pubescens) were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 ...

  12. The neglected intrinsic resistome of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Alicia Fajardo

    Full Text Available Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature.

  13. Bacterial pathogens modulate an apoptosis differentiation program in human neutrophils

    OpenAIRE

    Kobayashi, Scott D.; Braughton, Kevin R.; Whitney, Adeline R.; Voyich, Jovanka M.; Schwan, Tom G.; Musser, James M.; DeLeo, Frank R.

    2003-01-01

    Human polymorphonuclear leukocytes (PMNs or neutrophils) are essential to the innate immune response against bacterial pathogens. Recent evidence suggests that PMN apoptosis facilitates resolution of inflammation during bacterial infection. Although progress has been made toward understanding apoptosis in neutrophils, very little is known about transcriptional regulation of this process during bacterial infection. To gain insight into the molecular processes that facilitate resolution of infe...

  14. Higher plant diversity promotes higher diversity of fungal pathogens, while it decreases pathogen infection per plant

    OpenAIRE

    Rottstock, Tanja; Joshi, Jasmin; Kummer, Volker; Fischer, Markus

    2014-01-01

    Fungal plant pathogens are common in natural communities where they affect plant physiology, plant survival, and biomass production. Conversely, pathogen transmission and infection may be regulated by plant community characteristics such as plant species diversity and functional composition that favor pathogen diversity through increases in host diversity while simultaneously reducing pathogen infection via increased variability in host density and spatial heterogeneity. Therefore, a comprehe...

  15. Cellphones A Modern Stayhouse For Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Usha Arora

    2009-07-01

    Full Text Available Cellphones are increasingly used by health care personnels for communication. These can harbour variouspotential pathogens and become an exogenous source of nosocomial infections. A total of 160 cellphonesbelonging to doctors and paramedical staff working in various departments at govt. medical college andhospital, Amritsar were screened for bacterial isolates. Sterile swabs moistened with nutrient broth wereused to swab the front, back and the sides of the cellphones and were subjected to culture and sensitivity.The same procedure was repeated after decontamination with 70% iso propyl alcohol.Out of total 160cellphones growth was obtained in 65(40.62% cellphones. 31(19.37% from clinical workers and34(21.25% from non clinical workers. Coagulase negative staphylococcus was the most commonly isolatedorganism.The efficacy of decontamination with 70% isopropyl alcohol was found to be 98% as only 5cellphones showed growth after decontamination.It was found that around 40% of the cellphones ofhealth care workers were contaminated and thus acted as a potential source of nosocomial infections.Simple measures like decontamination with 70% isopropyl alcohol was found to be 98% effective.

  16. The influence of the accessory genome on bacterial pathogen evolution

    OpenAIRE

    Jackson, Robert W.; Vinatzer, Boris; Arnold, Dawn L.; Dorus, Steve; Murillo, Jesus

    2011-01-01

    Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens’ frequent e...

  17. EVALUATION OF ANTI-BACTERIAL ACTIVITY OF LOCAL FLORA OF BUNDELKHAND REGION OF JHANSI- INDIA AGAINST PLANT PATHOGENIC BACTERIA Xanthomonas campestris pv. campestris

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    Sazada Siddiqui

    2014-05-01

    Full Text Available Twenty plants namely Acacia nilotica (L. Willd.ex delil, Ageratum conyzoides Linn, Boerhaavia diffusa Linn., Cynodon dactylon (L. Pers, Cleome viscosa L, Datura stramonium Linn, Euphorbia hirta Linn, Ficus benghalensis Linn, Hyptis suaveolens (Linn poit, Hibiscus rosa-sinensis Linn, Jatropha gossypifolia Linn, Phyllanthus niruri webster, Prosopis juliflora, Polyalthia longifolia, Sida cordifolia, Tephrosia purpurea (Linn. Pers, Tridax procumbens Linn, Zizyphus jujube Linn, Solanum nigrum Linn, were collected from different localities and screened for their antibacterial activity against phytopathogenic bacterium, Xanthomonas campestris pv. campestris. Among all the tested species, nine plant species viz Acacia nilotica, Ageratum conyzoied, Boerhaavia diffusa, Cleome viscose, Datura stramonium, Euphorbia hirta, Hyptis suaveolens, Hibiscus rosa sinensis, Prosopis juliflora and Tridex procumbens showed medium to light antibacterial activity against the selected pathogens. Significant antibacterial activity was observed in aqueous extracts of Prosopsis juliflora, Hyptis suaveolens, Euphorbia hirta and Acacia nilotica

  18. Antibiotic Susceptibility and Immunomodulatory Potential of Chosen Bacterial Pathogens

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    M. Sujatha

    2010-01-01

    Full Text Available Problem statement: Antibiotic susceptibility is still the best way for bacterial pathogen escape mechanism against immunity. Approach: In the present investigation, bacterial pathogens like Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila, Klebsiella and Pseudomonas aeruginosa were used to screen antibiotic susceptibility and immunomodulatory potential. Results: All the test pathogens were sensitive to all the test antibiotics 11±2 mm except penicillin. The conditions for the preparation of antigens of intact natural composition and conformation from pathogens (whole cell and heat killed, were determined using Swiss albino mice (Balb/C as experimental species. Immunomodulatory potential of test pathogens were screened using animal model. Test pathogen decreases the body weight comparing that of normal mice, some notable changes were also noted in activity, growth, water consumption, feed consumption. Antibody titre level in animal serum decreased upto 50% in whole cell pathogen and heat killed pathogen treated animals. Conclusion: The five pathogens administered animals, decrement in B-lymphocyte was much pronounced in Pseudomonas aeruginosa followed by Escherichia coli, Staphylococcus aureus, Klebsiella sp., Aeromonas hydrophila in the 5 week. Pathogen treated mice showed an IgG suppressive effect. It is found to be suppressive to T cell production, so induction in cell mediated immunity has confirmed pathogenic potential of test pathogens. All these test pathogenic strains were remarkably suppressing immune system of pathogen exposed animals.

  19. Molecular battles between plant and pathogenic bacteria in the phyllosphere

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    C.M. Baker

    2010-08-01

    Full Text Available The phyllosphere, i.e., the aerial parts of the plant, provides one of the most important niches for microbial colonization. This niche supports the survival and, often, proliferation of microbes such as fungi and bacteria with diverse lifestyles including epiphytes, saprophytes, and pathogens. Although most microbes may complete the life cycle on the leaf surface, pathogens must enter the leaf and multiply aggressively in the leaf interior. Natural surface openings, such as stomata, are important entry sites for bacteria. Stomata are known for their vital role in water transpiration and gas exchange between the plant and the environment that is essential for plant growth. Recent studies have shown that stomata can also play an active role in limiting bacterial invasion of both human and plant pathogenic bacteria as part of the plant innate immune system. As counter-defense, plant pathogens such as Pseudomonas syringae pv tomato (Pst DC3000 use the virulence factor coronatine to suppress stomate-based defense. A novel and crucial early battleground in host-pathogen interaction in the phyllosphere has been discovered with broad implications in the study of bacterial pathogenesis, host immunity, and molecular ecology of bacterial diseases.

  20. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

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    Dongsheng Che

    2014-01-01

    Full Text Available High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs. PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms.

  1. Parallel bacterial evolution within multiple patients identifies candidate pathogenicity genes

    OpenAIRE

    Lieberman, Tami D; Michel, Jean-Baptiste; Aingaran, Mythili; Potter-Bynoe, Gail; Roux, Damien; Davis, Michael R.; Skurnik, David; Leiby, Nicholas; LiPuma, John J.; Goldberg, Joanna B.; McAdam, Alexander J.; Priebe, Gregory P.; Kishony, Roy

    2011-01-01

    Bacterial pathogens evolve during the infection of their human hosts 1-8 , but separating adaptive and neutral mutations remains challenging 9-11 . Here, we identify bacterial genes under adaptive evolution by tracking recurrent patterns of mutations in the same pathogenic strain during the infection of multiple patients. We conducted a retrospective study of a Burkholderia dolosa outbreak among people with cystic fibrosis, sequencing the genomes of 112 isolates collected from 14 individuals ...

  2. Hijacking of eukaryotic functions by intracellular bacterial pathogens

    OpenAIRE

    Alonso, Ana; García del Portillo, Francisco

    2004-01-01

    Intracellular bacterial pathogens have evolved as a group of microorganisms endowed with weapons to hijack many biological processes of eukaryotic cells. This review discusses how these pathogens perturb diverse host cell functions, such as cytoskeleton dynamics and organelle vesicular trafficking. Alteration of the cytoskeleton is discussed in the context of the bacterial entry process (invasion), which occurs either by activation of membrane-located host receptors ("zipper" mechani...

  3. Biological control of kiwifruit and tomato bacterial pathogens

    OpenAIRE

    Balestra, Dr Giorgio M.; Rossetti, Dr Antonio; Quattrucci, Dr Alessio

    2008-01-01

    Biocontrol of bacterial pathogens is effected by using cupric salts associate to appropriate agronomical practices such as seed certification, irrigation and fertilization. In in vitro and in in vivo tests, aqueous extracts from Allium sativum and Ficus carica fruits reduce the survival and the damages (disease incidence and disease severity) caused by bacterial pathogens of kiwifruit (Pseudomonas syringae pv. syringae, Pseudomonas viridiflava) and of tomato (Pseudomonas syringae pv. tomat...

  4. ANTIMICROBIAL ACTIVITY OF SOME MEDICINAL PLANTS AGAINST FISH PATHOGENS

    Directory of Open Access Journals (Sweden)

    Sharma Madhuri

    2012-04-01

    Full Text Available The present article elucidates on the antimicrobial (antibacterial and antifungal activity of some medicinal plants (herbs against different microbes (e.g., bacteria and fungi. Aquaculture has been a growing activity for more than 20 years worldwide. The bacterial infections are considered the major cause of mortality in aquaculture. Among the common fish pathogenic bacteria, Streptococcus agalactiae, Lactococcus garvieae, Enterococcus faecalis (all gram-positive, Aeromonas hydrophila and Yersinia ruckeri (both gram-negative cause infectious diseases. A. hydrophila, the most common bacterial pathogen in freshwater fish, has been recognized to be the aetiological agent of many pathological conditions, including tail rot, motile Aeromonas septicemia and epizootic ulcerative syndrome as a primary pathogen. The continuous use of antimicrobial agents in aquaculture has resulted into resistant bacterial strains in the aquatic environment. Treatment of bacterial diseases with different herbs has been safely used in organic agriculture, veterinary and human medicine. Treatment with medicinal plants having antibacterial activity is a potentially beneficial alternative in the aquaculture. These herbs mitigate many of the side effects which are associated with synthetic antimicrobials. Additionally, the plant-derived phytomedicines provide a cheaper source for treatment and greater accuracy than chemotherapeutic agents. Plants have been used as traditional medicine since time immemorial to control bacterial, viral and fungal diseases. In India, 500 medicinal plant species are used against pathogenic bacteria. Recently, research has been initiated to evaluate the feasibility of herbal drugs in fish diseases. Because of the growing bacterial resistance against commercial standard and reserve antibiotics, the search for new active substances with antibacterial activity against pathogenic bacteria is of increasing importance.

  5. The bacterial microbiome of Dermacentor andersoni ticks influences pathogen susceptibility.

    Science.gov (United States)

    Gall, Cory A; Reif, Kathryn E; Scoles, Glen A; Mason, Kathleen L; Mousel, Michelle; Noh, Susan M; Brayton, Kelly A

    2016-08-01

    Ticks are of medical importance owing to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Although ticks host pathogenic bacteria, they also harbor bacterial endosymbionts that have a role in tick physiology, survival, as well as pathogen acquisition and transmission. The goal of this study was to characterize the bacterial microbiome and examine the impact of microbiome disruption on pathogen susceptibility. The bacterial microbiome of two populations of D. andersoni with historically different susceptibilities to A. marginale was characterized. In this study, the microbiome was disrupted and then ticks were exposed to A. marginale or Francisella novicida to determine whether the microbiome correlated with pathogen susceptibility. Our study showed that an increase in proportion and quantity of Rickettsia bellii in the microbiome was negatively correlated to A. marginale levels in ticks. Furthermore, a decrease in Francisella endosymbionts was associated with lower F. novicida infection levels, demonstrating a positive pathogen-endosymbiont relationship. We demonstrate that endosymbionts and pathogens have varying interactions, and suggest that microbiome manipulation may provide a possible method for biocontrol by decreasing pathogen susceptibility of ticks. PMID:26882265

  6. Pathotypes of Bacterial Spot Pathogen Infecting Capsicum Peppers in Korea.

    Science.gov (United States)

    Wai, Khin Pa Pa; Siddique, Muhammad Irfan; Mo, Hwang-Sung; Yoo, Hee Ju; Byeon, Si-Eun; Jegal, Yoonhyuk; Mekuriaw, Alebel A; Kim, Byung-Soo

    2015-12-01

    Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp.) collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum) pepper plants carrying Bs1 , Bs2 and Bs3 , and PI235047 (C. pubescens) were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 and P8 were also observed. This is the first report of races P7 and P8 in Korea. The races P7 and P8 were differentiated from the former races P1 and P3, respectively, on the basis of their ability to elicit hypersensitive reactions to PI235047. PMID:26674555

  7. Pathotypes of Bacterial Spot Pathogen Infecting Capsicum Peppers in Korea

    Directory of Open Access Journals (Sweden)

    Khin Pa Pa Wai

    2015-12-01

    Full Text Available Sixty-seven isolates of bacterial spot pathogen (Xanthomonas spp. collected from six provinces of Korea were tested for the identification of their pathotypes and determination of their distribution throughout Korea in an effort to genetically manage the disease. Near isogenic lines of Early Calwonder (Capsicum annuum pepper plants carrying Bs₁, Bs₂ and Bs₃, and PI235047 (C. pubescens were used as differential hosts. Race P1 was found to be predominant, followed by race P7, and races P3 and P8 were also observed. This is the first report of races P7 and P8 in Korea. The races P7 and P8 were differentiated from the former races P1 and P3, respectively, on the basis of their ability to elicit hypersensitive reactions to PI235047.

  8. Looking in ticks for human bacterial pathogens

    OpenAIRE

    Mediannikov, Oleg; Fenollar, F.

    2014-01-01

    Ticks are considered to be second worldwide to mosquitoes as vectors of human diseases and the most important vectors of disease-causing pathogens in domestic- and wild animals. A number of emerging tick-borne pathogens are already discovered; however, the proportion of undiagnosed infectious diseases, especially in tropical regions, may suggest that there are still more pathogens associated with ticks. Moreover, the identification of bacteria associated with ticks may provide new tool for th...

  9. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Nielsen, Xiaohui Chen; Johansen, Ulla;

    2011-01-01

    Many bacteria can be detected in CF sputum, pathogenic and commensal. Modified Koch's criteria for identification of established and emerging CF pathogens are therefore described. Methods are described to isolate bacteria and to detect bacterial biofilms in sputum or lung tissue from CF patients ...

  10. Screening of endophytic bacteria against fungal plant pathogens.

    Science.gov (United States)

    Ohike, Tatsuya; Makuni, Kohei; Okanami, Masahiro; Ano, Takashi

    2013-12-01

    Bacterial endophytes were found from 6 plant leaves among 35 plant leaves screened. Two of the isolated bacteria showed antagonistic activity against fungal plant pathogens. An isolate named KL1 showed the clear inihibition against plant pathogens, Fusarium oxysporum and Rhizoctonia solani, on PDA as well as TSA plate. Supernatant of the bacterial culture also showed the clear inhibition against the fungal growth on the plate and the antibiotic substance was identified as iturin A by HPLC analysis. KL1 was identified as Bacillus sp. from the 16S rRNA gene analysis. Very thin hyphae of R. solani was miccroscopically observed when the fungus was co-cultivated with KL1. PMID:25078813

  11. List of New Names of Plant Pathogenic Bacteria (2011-2012)

    OpenAIRE

    Bull, C T; Coutinho, T. A.; Denny, T P; Firrao, G; Fischer-Le Saux, Marion; Li, X; Saddler, G. S.; Scortichini, M.; Stead, D.E.; Takikawa, Y

    2014-01-01

    The International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria has responsibility to evaluate the names of newly proposed pathovars for adherence to the International Standards for Naming Pathovars of Phytopathogenic Bacteria. Currently, the Comprehensive List of Names and the List of New Names of Plant Pathogenic Bacteria provide the authoritative register of names of bacterial plant pathogens. In this manuscript we up-date the list of names by cataloguin...

  12. Plant cell wall dynamics and wall-related susceptibility in plant-pathogen interactions

    OpenAIRE

    Daniela eBellincampi; Felice eCervone; Vincenzo eLionetti

    2014-01-01

    The cell wall is a dynamic structure that often determines the outcome of the interactions between plants and pathogens. It is a barrier that pathogens need to breach to colonize the plant tissue. While fungal necrotrophs extensively destroy the integrity of the cell wall through the combined action of degrading enzymes, biotrophic fungi require a more localized and controlled degradation of the cell wall in order to keep the host cells alive and utilize their feeding structures. Also bacteri...

  13. A bacterial pathogen uses distinct type III secretion systems to alternate between host kingdoms

    Science.gov (United States)

    Plant and animal-pathogenic bacteria utilize phylogenetically distinct type III secretion systems (T3SS) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. Pantoea stewartii subsp. stewartii (Pnss), the causative agent of Stewart’s bacterial wilt and...

  14. HYDRAULIC DISRUPTION AND PASSIVE MIGRATION BY A BACTERIAL PATHOGEN IN OAK TREE XYLEM

    Science.gov (United States)

    Xylella fastidiosa (Xf) is a xylem-limited bacterial pathogen that causes leaf scorch symptoms in numerous host plant species in urban, agricultural, and natural ecosystems worldwide. The exact mechanism of hydraulic disruption and systemic colonization of xylem by Xf remains elusive across all hos...

  15. Effects of Thai medicinal plants on pathogenic bacterial, growth performance, health condition and disease resistance in black tiger shrimp (Penaeus monodon Fabricius

    Directory of Open Access Journals (Sweden)

    Klowkliang, T.

    2005-02-01

    Full Text Available Chemical analysis of turmeric (Curcuma longa extracts using TLC/densitometry, showed an extract contain 21.57%w/w of three important curcuminoids: curcumin, desmethoxycurcumin and bisdesmethoxycurcumin. GC and MS were used to analyze volatile oils. Aromatic turmerone, α-turmerone and zingiberene were also obtained. Qualitative and quantitative analyses alcoholic extract of Andrographis paniculata using TLC, revealed that the extracts contain three important compounds in total lactone of 30.49% w/w. There are andrographolide,14-deoxy-11-12-didehydroandrographolide and neoandrographolide. TLC-chromatogram of Clinacanthus nutans extract after reacted with anisaldehyde/sulfuric acid showed a 9 key compounds, while preliminary neutralization test of the compounds revealed that there were active compounds against HSV-1 virus. In vitro efficacy test revealed that Curcuma longa and Andrographis paniculata extracts at 250 and 1,500 mg/L could eradicate 15 isolates of Vibrio spp. which were isolated from infected shrimps. Effects of medicinal plant extracts incorporated into the diet on shrimp immune responses were investigated. Shrimp fed diet containing Clinacanthus nutans extract at 20 mg/kg of diet had good growth, FCR and immune responses. The shrimp that were fed diet containing Curcuma longa extracts at 25 mg/kg of diet for 7-14 days showed high resistance to Vibrio harveyi. Likewise, the shrimp fed Andrographis paniculata extract at 25 mg/ kg of diet for 14 days had a higher resistance to WSSV. Incorporating the medicinal extracts at higher levels resulted in reduction in diet palatability which consequently had an effect on a decrease in growth, immune responses and resistance to bacterial and WSSV infection.

  16. Shotgun proteomics of bacterial pathogens: advances, challenges and clinical implications.

    Science.gov (United States)

    Semanjski, Maja; Macek, Boris

    2016-02-01

    Mass spectrometry-based proteomics is increasingly used in analysis of bacterial pathogens. Simple experimental set-ups based on high accuracy mass spectrometry and powerful biochemical and bioinformatics tools are capable of reliably quantifying levels of several thousand bacterial proteins in a single experiment, reaching the analytical capacity to completely map whole proteomes. Here the authors present the state-of-the-art in bacterial pathogen proteomics and discuss challenges that the field is facing, especially in analysis of low abundant, modified proteins from organisms that are difficult to culture. Constant improvements in speed and sensitivity of mass spectrometers, as well as in bioinformatic and biochemical workflows will soon allow for comprehensive analysis of regulatory mechanisms of pathogenicity and enable routine application of proteomics in the clinical setting. PMID:26653908

  17. The intrinsic resistome of bacterial pathogens

    OpenAIRE

    Olivares, Jorge; Bernardini, Alejandra; Garcia-Leon, Guillermo; Corona, Fernando; B. Sanchez, Maria; Martinez, Jose L.

    2013-01-01

    Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that...

  18. Bacterial interactions in pathogenic subgingival plaque.

    Science.gov (United States)

    Ng, Hong Min; Kin, Lin Xin; Dashper, Stuart G; Slakeski, Nada; Butler, Catherine A; Reynolds, Eric C

    2016-05-01

    Chronic periodontitis has a polymicrobial biofilm aetiology. Polymicrobial biofilms are complex, dynamic microbial communities formed by two or more bacterial species that are important for the persistence and proliferation of participating microbes in the environment. Interspecies adherence, which often involves bacterial surface-associated molecules, and communications are essential in the spatial and temporal development of a polymicrobial biofilm, which in turn is necessary for the overall fitness of a well-organized multispecies biofilm community. In the oral cavity, interactions between key oral bacterial species, including Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, are essential for the progression of chronic periodontitis. In vivo, P. gingivalis and T. denticola are frequently found to co-exist in deep periodontal pockets and have been co-localized to the superficial layers of subgingival plaque as microcolony blooms adjacent to the pocket epithelium, suggesting possible interbacterial interactions that contribute towards disease. The motility and chemotactic ability of T. denticola, although not considered as classic virulence factors, are likely to be important in the synergistic biofilm formation with P. gingivalis. In vitro, P. gingivalis and T. denticola display a symbiotic relationship in nutrient utilization and growth promotion. Together these data suggest there is an intimate relationship between these two species that has evolved to enhance their survival and virulence. PMID:26541672

  19. Plant Pathogen Population Dynamics in Potato Fields

    OpenAIRE

    Morgan, G. D.; Stevenson, W. R.; MacGuidwin, A. E.; Kelling, K. A.; Binning, L. K.; Zhu, J.

    2002-01-01

    Modern technologies incorporating Geographic Information Systems (GIS), Global Positioning Systems (GPS), remote sensing, and geostatistics provide unique opportunities to advance ecological understanding of pests across a landscape. Increased knowledge of the population dynamics of plant pathogens will promote management strategies, such as site-specific management, and cultural practices minimizing the introduction and impact of plant pathogens. The population dynamics of Alternaria solani,...

  20. Detection of major diarrheagenic bacterial pathogens by multiplex PCR panels.

    Science.gov (United States)

    Sjöling, Åsa; Sadeghipoorjahromi, Leila; Novak, Daniel; Tobias, Joshua

    2015-03-01

    Diarrheal diseases remain a major threat to the youngest population in low- and middle-income countries. The main bacterial pathogens causing diarrhea are diarrheagenic Escherichia coli (DEC) that consists of enteroaggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohemorrhagic EHEC and enteroinvasive E. coli (EIEC), Salmonella, Shigella spp. (S. dysenteria, S. sonnei, S. flexneri) Campylobacter (C. coli, C. jejuni), Vibrio (V. vulnificus, V. parahaemolyticusm, V. cholerae), Yersinia enterocolitica and Aeromonas hydrophila. The aim of this study was to set up rapid multiplex PCR (mPCR) panels to identify these diarrheagenic pathogens based on their specific virulence genes. Primers against specific target genes were combined into three mPCR panels: one for diarrheal E. coli, one for pathogens causing mainly bloody diarrhea, and the third for the remaining pathogens. The panels were tested against a set of stool samples from Swedish children with diarrhea and controls and the analysis identified bacterial pathogens in 14/54 (26%) of the samples. These results show that our three developed mPCR panels can detect main bacterial diarrheagenic pathogens in clinical samples. PMID:25542594

  1. 冬凌草内生细菌的分离鉴定及其对植物病害的生防作用%Isolation & Identification of Entophytic Bacterial Strain from Rabdosia rubescens & Its Biocontrol Effects against Plant Pathogens

    Institute of Scientific and Technical Information of China (English)

    柯杨; 马瑜; 沈莹华; 李勃

    2013-01-01

    An enlophylic bacterial strain KD3 isolated from the tissue of Rabdosia rubescens ( Hemsl. ) H. Hara obviously had antagonism against many crop fungal pathogens. This strain was identified as Bacillus sublilis according to its morphological, physiological and biochemical characteristics and 16S rRNA sequence analysis. The results of antagonism test showed that strain KD3 could control the plant pathogens effectively, which exhibited a good application and development potential.%从冬凌草(Rabdosia rubescens (Hemsl.) H.Hara)中分离筛选出1株对多种作物真菌病害具有显著拮抗作用的细菌,命名为KD3.通过其形态特征和生理生化特性以及16S rRNA序列的同源性分析,鉴定该菌株为枯草芽胞杆菌(Bacillus subtilis).试验表明,KD3菌株能够显著抑制多种病原真菌的侵染,具有良好的应用开发潜力.

  2. Immunity to plant pathogens and iron homeostasis.

    Science.gov (United States)

    Aznar, Aude; Chen, Nicolas W G; Thomine, Sebastien; Dellagi, Alia

    2015-11-01

    Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens. Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against pathogens and plant response to iron deficiency share several features, such as secretion of phenolic compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization during infection involves genes coding iron transport and iron storage proteins, which have been shown to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen attack is strongly dependent on the nature of the pathogen infection strategy and on the host species. Microbial siderophores emerged as important factors as they have the ability to trigger plant defense responses. Depending on the plant species, siderophore perception can be mediated by their strong iron scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity. PMID:26475190

  3. Bacterial Gibberellins Induce Systemic Resistance of Plants

    Directory of Open Access Journals (Sweden)

    I. N. FEKLISTOVA

    2014-06-01

    Full Text Available It is generally agreed today that some rhizosphere bacteria can ensure induced systemic resistance to pathogens. In this paper we tested the ability of gibberellins produced by rhizosphere non-pathogenic bacteria Pseudomonas aurantiaca to induce systemic resistance to alternariosis agent – Alternaria brassicicola – in oilseed rape plants.Oilseed rape (Brássica nápus is one of the most promising oil-bearing croppers. It allows improving the supply of population with vegetable oil, animal and poultry industries with high quality vegetable protein. It is used for biofuel production as well.Gibberellin preparation was isolated from liquid culture of strain Pseudomonas aurantiaca grown in 250 mL of M9 medium (48 h, 28 °C under darkroom conditions. Gibberellins were extracted according procedure described by Tien et al. (1979. Gibberellins concentration in the medium was determined by fluorometric method.Elicitor activity of bacterial metabolites – gibberellins – was analyzed in model system of artificial inoculation of oilseed rape germs with phytopathogenic fungi Alternaria brassicicola. The elicitor action efficiency was evaluated on the 15th day of oilseed rape cultivation based on the percentage of leaf surface covered by necrotic lesions.Gibberellins were shown to induce systemic resistance resulted in decreasing of oil seed plants   vulnerability by 52.7%.It is known that under the unfavorable conditions plants synthesis the reactive oxygen intermediates   which activate destructive processes. One of the first organism reactions to stress action is the change of the lipid peroxidation level. It was shown that treatment of the soil with gibberellins resulted in decreasing of the lipid peroxidation level twofold.Gibberellins were shown to have a similar effect on permeability of cell membranes for free nucleotides. The permeability of cell membranes in leaves decreased 2.8-fold at room temperature. We suggest that gibberellins

  4. Bacterial pathogens in a reactor cooling reservoir

    International Nuclear Information System (INIS)

    The results of the sampling in both Par Pond and Clark Hill Reservoir are given. The frequency of isolation is a qualitative parameter which indicates how often the specified bacterium was isolated from each habitat. Initial scoping experiments demonstrated that a wider variety of pathogenic bacteria occur in Par Pond than in Clark Hill Reservoir. Such findings are interesting because Par Pond does not receive any human wastes directly, yet bacteria generally associated with human wastes are more frequently isolated from Par Pond. Previous studies have demonstrated that certain non-spore-forming enteric bacteria do not survive the intense heat associated with the cooling water when the reactor is operating. However, even when the reactor is not operating, cooling water, consisting of 10% makeup water from Savannah River, continues to flow into Par Pond. This flow provides a source of bacteria which inoculate Par Pond. Once the reactor is again operating, these same bacteria appear to be able to survive and grow within the Par Pond system. Thus, Par Pond and the associated lakes and canals of the Par Pond system provide a pool of pathogens that normally would not survive in natural waters

  5. Ecological niche of plant pathogens

    OpenAIRE

    Ecaterina Fodor

    2011-01-01

    Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in ni...

  6. Phytophthora parasitica: a model oomycete plant pathogen

    OpenAIRE

    Meng, Yuling; Qiang ZHANG; Ding, Wei; Shan, Weixing

    2014-01-01

    Oomycetes are eukaryotic microorganisms morphologically similar to but phylogenetically distant from true fungi. Most species in the genus Phytophthora of oomycetes are devastating plant pathogens, causing damages to both agricultural production and natural ecosystems. Tremendous progress has been achieved in recent years in diversity, evolution and lifestyles of oomycete plant pathogens, as well as on the understanding of genetic and molecular basis of oomycete-plant interactions. Phytophtho...

  7. ANTIMICROBIAL ACTIVITY OF SOME MEDICINAL PLANTS AGAINST FISH PATHOGENS

    OpenAIRE

    Sharma Madhuri; Mandloi A.K.; Pandey Govind; Sahni Y.P.

    2012-01-01

    The present article elucidates on the antimicrobial (antibacterial and antifungal) activity of some medicinal plants (herbs) against different microbes (e.g., bacteria and fungi). Aquaculture has been a growing activity for more than 20 years worldwide. The bacterial infections are considered the major cause of mortality in aquaculture. Among the common fish pathogenic bacteria, Streptococcus agalactiae, Lactococcus garvieae, Enterococcus faecalis (all gram-positive), Aeromonas hydrophila and...

  8. Pathogen threat assessment is predictive plant pathology

    Science.gov (United States)

    The American Society of Plant Pathologists has maintained a formal effort to prioritize threatening and emerging crop pathogens for over 70 years, and the APS Emerging Pathogens and Diseases Committee is continuing the process. In order to accomplish prioritization in a rigorous fashion, criteria mu...

  9. Antibacterial activity of caffeine against plant pathogenic bacteria.

    Science.gov (United States)

    Sledz, Wojciech; Los, Emilia; Paczek, Agnieszka; Rischka, Jacek; Motyka, Agata; Zoledowska, Sabina; Piosik, Jacek; Lojkowska, Ewa

    2015-01-01

    The objective of the present study was to evaluate the antibacterial properties of a plant secondary metabolite - caffeine. Caffeine is present in over 100 plant species. Antibacterial activity of caffeine was examined against the following plant-pathogenic bacteria: Ralstonia solanacearum (Rsol), Clavibacter michiganesis subsp. sepedonicus (Cms), Dickeya solani (Dsol), Pectobacterium atrosepticum (Pba), Pectobacterium carotovorum subsp. carotovorum (Pcc), Pseudomonas syringae pv. tomato (Pst), and Xanthomonas campestris subsp. campestris (Xcc). MIC and MBC values ranged from 5 to 20 mM and from 43 to 100 mM, respectively. Caffeine increased the bacterial generation time of all tested species and caused changes in cell morphology. The influence of caffeine on the synthesis of DNA, RNA and proteins was investigated in cultures of plant pathogenic bacteria with labelled precursors: [(3)H]thymidine, [(3)H]uridine or (14)C leucine, respectively. RNA biosynthesis was more affected than DNA or protein biosynthesis in bacterial cells treated with caffeine. Treatment of Pba with caffeine for 336 h did not induce resistance to this compound. Caffeine application reduced disease symptoms caused by Dsol on chicory leaves, potato slices, and whole potato tubers. The data presented indicate caffeine as a potential tool for the control of diseases caused by plant-pathogenic bacteria, especially under storage conditions. PMID:26307771

  10. Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Zebenay Gezahegn; Mohd Sayeed Akhtar; Delelegn Woyessa; Yinebeb Tariku

    2015-01-01

    Objective:To isolate and characterize the food associated bacterial strains, and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents (acetone, chloroform, methanol and petroleum ether) leaf extracts of Thevetia peruviana (T. peruviana) against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant. Methods:The food associated bacterial strains were isolated from students' lunch boxes in Tesfa Tewahido Primary School. The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods, respectively and phytochemical constituents were also detected in various solvent leaf extracts of T. peruviana. Results:The result showed that all the tested solvent leaf extracts of T. peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm. Amongst the tested food borne bacterial pathogens, Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T. peruviana while, methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains. Minimum inhibitory concentration of various solvent leaf extracts of T. peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains. The phytochemical constituents screening on the leaf extracts of T. peruviana showed the presence of alkaloids, cardiac glycosides, flavonoids, polyphenols, saponins and tannins. Conclusions:The present study suggests that T. peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.

  11. Estimating Bacterial Pathogen Levels in New Zealand Bulk Tank Milk.

    Science.gov (United States)

    Marshall, J C; Soboleva, T K; Jamieson, P; French, N P

    2016-05-01

    Zoonotic bacteria such as Campylobacter, Listeria, and Shiga toxin-producing Escherichia coli have been found in bulk tank milk in many countries, and the consumption of raw milk has been implicated in outbreaks of disease in New Zealand. Fecal contamination at milking is probably the most common source of pathogenic bacteria in bulk tank milk. Raw milk was collected from 80 New Zealand dairy farms during 2011 and 2012 and tested periodically for Campylobacter, E. coli O157, Listeria monocytogenes, and Salmonella. Milk quality data such as coliform counts, total bacterial counts, and somatic cell counts also were collected. By treating the total bacterial count as a proxy for fecal contamination of milk and utilizing farm and animal level prevalence and shedding rates of each pathogen, a predictive model for the level of pathogenic bacteria in bulk tank raw milk was developed. The model utilizes a mixture distribution to combine the low level of contamination inherent in the milking process with isolated contamination events associated with significantly higher pathogen levels. By simulating the sampling and testing process, the predictive model was validated against the observed prevalence of each pathogen in the survey. The predicted prevalence was similar to the observed prevalence for E. coli O157 and Salmonella, although the predicted prevalence was higher than that observed in samples tested for Campylobacter. PMID:27296424

  12. Advances on Plant Pathogenic Mycotoxin Binding Proteins

    Institute of Scientific and Technical Information of China (English)

    WANG Chao-hua; DONG Jin-gao

    2002-01-01

    Toxin-binding protein is one of the key subjects in plant pathogenic mycotoxin research. In this paper, new advances in toxin-binding proteins of 10 kinds of plant pathogenic mycotoxins belonging to Helminthosporium ,Alternaria ,Fusicoccum ,Verticillium were reviewed, especially the techniques and methods of toxin-binding proteins of HS-toxin, HV-toxin, HMT-toxin, HC-toxin. It was proposed that the isotope-labeling technique and immunological chemistry technique should be combined together in research of toxin-binding protein, which will be significant to study the molecular recognition mechanism between host and pathogenic fungus.

  13. Importance of prophages to evolution and virulence of bacterial pathogens.

    Science.gov (United States)

    Fortier, Louis-Charles; Sekulovic, Ognjen

    2013-07-01

    Bacteriophages, or simply phages, are viruses infecting bacteria. With an estimated 10 ( 31) particles in the biosphere, phages outnumber bacteria by a factor of at least 10 and not surprisingly, they influence the evolution of most bacterial species, sometimes in unexpected ways. "Temperate" phages have the ability to integrate into the chromosome of their host upon infection, where they can reside as "quiescent" prophages until conditions favor their reactivation. Lysogenic conversion resulting from the integration of prophages encoding powerful toxins is probably the most determinant contribution of prophages to the evolution of pathogenic bacteria. We currently grasp only a small fraction of the total phage diversity. Phage biologists keep unraveling novel mechanisms developed by phages to parasitize their host. The purpose of this review is to give an overview of some of the various ways by which prophages change the lifestyle and boost virulence of some of the most dangerous bacterial pathogens. PMID:23611873

  14. Defining pathogenic bacterial species in the genomic era

    OpenAIRE

    DidierRaoult

    2011-01-01

    Actual definitions of bacterial species are limited due to the current criteria of definition and the use of restrictive genetic tools. The 16S rRNA sequence, for example, has been widely used as a marker for phylogenetic analyses; however, its use often leads to misleading species definitions. According to the first genetic studies, removing a certain number of genes from pathogenic bacteria removes their capacity to infect hosts. However, more recent studies have demonstrated that the speci...

  15. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms

    OpenAIRE

    Mansilla Pareja, Maria Eugenia; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will d...

  16. Genetic diversity of citrus bacterial canker pathogens preserved in herbarium specimens

    OpenAIRE

    Li, Wenbin; Song, Qijian; Brlansky, Ronald H.; Hartung, John S.

    2007-01-01

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) was first documented in India and Java in the mid 19th century. Since that time, the known distribution of the disease has steadily increased. Concurrent with the dispersion of the pathogen, the diversity of described strains continues to increase, with novel strains appearing in Saudi Arabia, Iran, and Florida in the last decade. Herbarium specimens of infected plants provide an historical record documenting both ...

  17. New insight into a complex plant-fungal pathogen interaction

    Science.gov (United States)

    The coevolution of plants and microbes has shaped plant mechanisms that detect and repel pathogens. A newly identified plant gene confers partial resistance to a fungal pathogen not by preventing initial infection, but by limiting its spread through the plant. ...

  18. Cutaneous bacterial species from Lithobates catesbeianus can inhibit pathogenic dermatophytes.

    Science.gov (United States)

    Lauer, Antje; Hernandez, Trang

    2015-04-01

    Antibiotics are being successfully used to fight many infectious diseases caused by pathogenic microorganisms. However, new infectious diseases are continuously being identified, and some known pathogens are becoming resistant against known antibiotics. Furthermore, many antifungals are causing serious side effects in long-term treatments of patients, and many skin infections caused by dermatophytes are difficult to cure. The beneficial roles of resident cutaneous microbiota to inhibit pathogenic microorganisms have been shown for many vertebrate species. Microbial symbionts on the amphibian skin for example can be a source of powerful antimicrobial metabolites that can protect amphibians against diseases, such as chytridiomycosis, caused by a fungal pathogen. In this research, we investigated whether cutaneous bacterial species isolated from Lithobates catesbeianus (North American bullfrog), an invasive amphibian species that is resistant to chytridiomycosis, produce secondary metabolites that can be used to inhibit the growth of three species of dermatophytes (Microsporum gypseum, Epidermophyton floccosum, and Trichophyton mentagrophytes) which are known to cause topical or subdermal skin infections in humans. Strongly anti-dermatophyte bacterial species that belonged to the Bacillaceae, Streptomycetaceae, Pseudomonadaceae, Xanthomonadaceae, Aeromonadaceae, and Enterobacteriaceae were identified. This research has provided evidence of the presence of cutaneous anti-dermatophyte bacteria from L. catesbeianus which might provide a basis for health care providers to experiment with new antifungals in the future. PMID:25431089

  19. The Interaction of Human Enteric Pathogens with Plants

    OpenAIRE

    Lim, Jeong-A; Lee, Dong Hwan; Heu, Sunggi

    2014-01-01

    There are an increasing number of outbreaks of human pathogens related to fresh produce. Thus, the growth of human pathogens on plants should be explored. Human pathogens can survive under the harsh environments in plants, and can adhere and actively invade plants. Plant-associated microbiota or insects contribute to the survival and transmission of enteric pathogens in plants. Human enteric pathogens also trigger plant innate immunity, but some pathogens–such as Salmonella–can overcome this ...

  20. Histone Acetylation in Fungal Pathogens of Plants

    Directory of Open Access Journals (Sweden)

    Junhyun Jeon

    2014-03-01

    Full Text Available Acetylation of histone lysine residues occurs in different organisms ranging from yeast to plants and mammals for the regulation of diverse cellular processes. With the identification of enzymes that create or reverse this modification, our understanding on histone acetylation has expanded at an amazing pace during the last two decades. In fungal pathogens of plants, however, the importance of such modification has only just begun to be appreciated in the recent years and there is a dearth of information on how histone acetylation is implicated in fungal pathogenesis. This review covers the current status of research related to histone acetylation in plant pathogenic fungi and considers relevant findings in the interaction between fungal pathogens and host plants. We first describe the families of histone acetyltransferases and deacetylases. Then we provide the cases where histone acetylation was investigated in the context of fungal pathogenesis. Finally, future directions and perspectives in epigenetics of fungal pathogenesis are discussed.

  1. The Comprehensive Phytopathogen Genomics Resource: a web-based resource for data-mining plant pathogen genomes

    OpenAIRE

    Hamilton, John P; Neeno-Eckwall, Eric C; Adhikari, Bishwo N.; Perna, Nicole T; Tisserat, Ned; Leach, Jan E.; Lévesque, C. André; Buell, C. Robin

    2011-01-01

    The Comprehensive Phytopathogen Genomics Resource (CPGR) provides a web-based portal for plant pathologists and diagnosticians to view the genome and trancriptome sequence status of 806 bacterial, fungal, oomycete, nematode, viral and viroid plant pathogens. Tools are available to search and analyze annotated genome sequences of 74 bacterial, fungal and oomycete pathogens. Oomycete and fungal genomes are obtained directly from GenBank, whereas bacterial genome sequences are downloaded from th...

  2. Effects of rainfall acidification on plant pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Shriner, D. S.; Cowling, E. B.

    1978-01-01

    Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The chemical nature of the aqueous microenvironment at the infection court is a potentially significant factor in the successful dissemination, establishment, and survival of plant pathogenic microorganisms. Acidic rainfall has a potential for influencing not only the pathogen, but also the host organism, and the host-pathogen complex. Although host-pathogen interactions add a degree of complexity to the study of abiotic environmental stress of plants, it is our hope, through the use of a combination of general concepts, theoretical postulations, and experimental data, to describe the potential role that rainfall acidity may play in the often subtle balance between populations of plants and populations of plant pathogens. The direct effects of acidic precipitation on vegetation are becoming increasingly better understood. The indirect consequences of both acute and chronic exposure of vegetation to acidic precipitation are very complex, however. Their effect is variable in time, and involves a variety of potential interactions which are only partially understood.

  3. Suppression of soil-borne plant pathogens

    OpenAIRE

    Agtmaal, van, E.L.

    2015-01-01

    Soil borne plant pathogens considerably reduce crop yields worldwide and are difficult to control due to their ”masked” occurrence  in the heterogeneous soil environment. This hampers the efficacy of chemical - and microbiological control agents.   Outbreaks of crop diseases are not only dependent on the presence of pathogen propagules in the soil, but are also influenced by soil-related properties like physico-chemical characteristics, microbial activity and commun...

  4. Temperature-induced behavioral switches in a bacterial coral pathogen.

    Science.gov (United States)

    Garren, Melissa; Son, Kwangmin; Tout, Jessica; Seymour, Justin R; Stocker, Roman

    2016-06-01

    Evidence to date indicates that elevated seawater temperatures increase the occurrence of coral disease, which is frequently microbial in origin. Microbial behaviors such as motility and chemotaxis are often implicated in coral colonization and infection, yet little is known about the effect of warming temperatures on these behaviors. Here we present data demonstrating that increasing water temperatures induce two behavioral switches in the coral pathogen Vibrio coralliilyticus that considerably augment the bacterium's performance in tracking the chemical signals of its coral host, Pocillopora damicornis. Coupling field-based heat-stress manipulations with laboratory-based observations in microfluidic devices, we recorded the swimming behavior of thousands of individual pathogen cells at different temperatures, associated with current and future climate scenarios. When temperature reached ⩾23 °C, we found that the pathogen's chemotactic ability toward coral mucus increased by >60%, denoting an enhanced capability to track host-derived chemical cues. Raising the temperature further, to 30 °C, increased the pathogen's chemokinetic ability by >57%, denoting an enhanced capability of cells to accelerate in favorable, mucus-rich chemical conditions. This work demonstrates that increasing temperature can have strong, multifarious effects that enhance the motile behaviors and host-seeking efficiency of a marine bacterial pathogen. PMID:26636553

  5. Detection of bacterial pathogens in environmental samples using DNA microarrays.

    Science.gov (United States)

    Call, Douglas R; Borucki, Monica K; Loge, Frank J

    2003-05-01

    Polymerase chain reaction (PCR) is an important tool for pathogen detection, but historically, it has not been possible to accurately identify PCR products without sequencing, Southern blots, or dot-blots. Microarrays can be coupled with PCR where they serve as a set of parallel dot-blots to enhance product detection and identification. Microarrays are composed of many discretely located probes on a solid substrate such as glass. Each probe is composed of a sequence that is complimentary to a pathogen-specific gene sequence. PCR is used to amplify one or more genes and the products are then hybridized to the array to identify species-specific polymorphism within one or more genes. We illustrate this type of array using 16S rDNA probes suitable for distinguishing between several salmonid pathogens. We also describe the use of microarrays for direct detection of either RNA or DNA without the aid of PCR, although the sensitivity of these systems currently limits their application for pathogen detection. Finally, microarrays can also be used to "fingerprint" bacterial isolates and they can be used to identify diagnostic markers suitable for developing new PCR-based detection assays. We illustrate this type of array for subtyping an important food-borne pathogen, Listeria monocytogenes. PMID:12654494

  6. Molecular Detection of Common Bacterial Pathogens Causing Meningitis

    Directory of Open Access Journals (Sweden)

    H Sadighian

    2009-03-01

    Full Text Available "nBackground: The clinical diagnosis of meningitis is crucial, particularly in children. The early diagnosis and empiric an­tibi­otic treatments have led to a reduction in morbidity and mortality rates. PCR and the enzymatic digestion of 16SrDNA frag­ment which is produced by universal primers led up fast and sensitive determination. The purpose of this study was to investi­gate a rapid method for detection of common bacterial pathogens causing meningitis."nMethods: According to the gene encoding 16SrDNA found in all bacteria, a pair of primers was designed. Then the univer­sal PCR was performed for bacterial agents of meningitis (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influ­enzae, etc. by employing broad- range DNA extraction method. The ob­tained uni­versal PCR products were digested with restriction enzymes (HaeIII, AluI and MnlI to identify bacterial species. "nResults: By the enzymatic digestion of the universal products of each standard strain of the above bacteria, specific patterns were achieved. These specific patterns may be used for comparison in CSF examination. The analytical sensitivity of the as­say was approximately 1.5´102 CFU/ml of CSF even in samples with high amount of proteins. Conclusion: The universal PCR coupled with enzymatic digestion can be used to detect and identify bacterial pathogens in clini­cal specimens rapidly and accurately. Molecular diagnostic of bacterial meningitis, though expensive and labor-inten­sive, but is valuable and critical in patient management.

  7. Genome Assembly and Computational Analysis Pipelines for Bacterial Pathogens

    KAUST Repository

    Rangkuti, Farania Gama Ardhina

    2011-06-01

    Pathogens lie behind the deadliest pandemics in history. To date, AIDS pandemic has resulted in more than 25 million fatal cases, while tuberculosis and malaria annually claim more than 2 million lives. Comparative genomic analyses are needed to gain insights into the molecular mechanisms of pathogens, but the abundance of biological data dictates that such studies cannot be performed without the assistance of computational approaches. This explains the significant need for computational pipelines for genome assembly and analyses. The aim of this research is to develop such pipelines. This work utilizes various bioinformatics approaches to analyze the high-­throughput genomic sequence data that has been obtained from several strains of bacterial pathogens. A pipeline has been compiled for quality control for sequencing and assembly, and several protocols have been developed to detect contaminations. Visualization has been generated of genomic data in various formats, in addition to alignment, homology detection and sequence variant detection. We have also implemented a metaheuristic algorithm that significantly improves bacterial genome assemblies compared to other known methods. Experiments on Mycobacterium tuberculosis H37Rv data showed that our method resulted in improvement of N50 value of up to 9697% while consistently maintaining high accuracy, covering around 98% of the published reference genome. Other improvement efforts were also implemented, consisting of iterative local assemblies and iterative correction of contiguated bases. Our result expedites the genomic analysis of virulent genes up to single base pair resolution. It is also applicable to virtually every pathogenic microorganism, propelling further research in the control of and protection from pathogen-­associated diseases.

  8. Pathogen-induced conditioning of the primary xylem vessels - a prerequisite for the formation of bacterial emboli by Pectobacterium atrosepticum.

    Science.gov (United States)

    Gorshkov, V Y; Daminova, A G; Mikshina, P V; Petrova, O E; Ageeva, M V; Salnikov, V V; Gorshkova, T A; Gogolev, Y V

    2016-07-01

    Representatives of Pectobacterium genus are some of the most harmful phytopathogens in the world. In the present study, we have elucidated novel aspects of plant-Pectobacterium atrosepticum interactions. This bacterium was recently demonstrated to form specific 'multicellular' structures - bacterial emboli in the xylem vessels of infected plants. In our work, we showed that the process of formation of these structures includes the pathogen-induced reactions of the plant. The colonisation of the plant by P. atrosepticum is coupled with the release of a pectic polysaccharide, rhamnogalacturonan I, into the vessel lumen from the plant cell wall. This polysaccharide gives rise to a gel that serves as a matrix for bacterial emboli. P. atrosepticum-caused infection involves an increase of reactive oxygen species (ROS) levels in the vessels, creating the conditions for the scission of polysaccharides and modification of plant cell wall composition. Both the release of rhamnogalacturonan I and the increase in ROS precede colonisation of the vessels by bacteria and occur only in the primary xylem vessels, the same as the subsequent formation of bacterial emboli. Since the appearance of rhamnogalacturonan I and increase in ROS levels do not hamper the bacterial cells and form a basis for the assembly of bacterial emboli, these reactions may be regarded as part of the susceptible response of the plant. Bacterial emboli thus represent the products of host-pathogen integration, since the formation of these structures requires the action of both partners. PMID:26992469

  9. Bacterial Outer Membrane Vesicles Induce Plant Immune Responses.

    Science.gov (United States)

    Bahar, Ofir; Mordukhovich, Gideon; Luu, Dee Dee; Schwessinger, Benjamin; Daudi, Arsalan; Jehle, Anna Kristina; Felix, Georg; Ronald, Pamela C

    2016-05-01

    Gram-negative bacteria continuously pinch off portions of their outer membrane, releasing membrane vesicles. These outer membrane vesicles (OMVs) are involved in multiple processes including cell-to-cell communication, biofilm formation, stress tolerance, horizontal gene transfer, and virulence. OMVs are also known modulators of the mammalian immune response. Despite the well-documented role of OMVs in mammalian-bacterial communication, their interaction with plants is not well studied. To examine whether OMVs of plant pathogens modulate the plant immune response, we purified OMVs from four different plant pathogens and used them to treat Arabidopsis thaliana. OMVs rapidly induced a reactive oxygen species burst, medium alkalinization, and defense gene expression in A. thaliana leaf discs, cell cultures, and seedlings, respectively. Western blot analysis revealed that EF-Tu is present in OMVs and that it serves as an elicitor of the plant immune response in this form. Our results further show that the immune coreceptors BAK1 and SOBIR1 mediate OMV perception and response. Taken together, our results demonstrate that plants can detect and respond to OMV-associated molecules by activation of their immune system, revealing a new facet of plant-bacterial interactions. PMID:26926999

  10. Coronatine inhibits stomatal closure and delays hypersensitive response cell death induced by nonhost bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Seonghee Lee

    2013-02-01

    Full Text Available Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR, which acts as a jasmonic acid mimic and inhibits plant defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.

  11. Plant Natural Products Targeting Bacterial Virulence Factors.

    Science.gov (United States)

    Silva, Laura Nunes; Zimmer, Karine Rigon; Macedo, Alexandre José; Trentin, Danielle Silva

    2016-08-24

    Decreased antimicrobial efficiency has become a global public health issue. The paucity of new antibacterial drugs is evident, and the arsenal against infectious diseases needs to be improved urgently. The selection of plants as a source of prototype compounds is appropriate, since plant species naturally produce a wide range of secondary metabolites that act as a chemical line of defense against microorganisms in the environment. Although traditional approaches to combat microbial infections remain effective, targeting microbial virulence rather than survival seems to be an exciting strategy, since the modulation of virulence factors might lead to a milder evolutionary pressure for the development of resistance. Additionally, anti-infective chemotherapies may be successfully achieved by combining antivirulence and conventional antimicrobials, extending the lifespan of these drugs. This review presents an updated discussion of natural compounds isolated from plants with chemically characterized structures and activity against the major bacterial virulence factors: quorum sensing, bacterial biofilms, bacterial motility, bacterial toxins, bacterial pigments, bacterial enzymes, and bacterial surfactants. Moreover, a critical analysis of the most promising virulence factors is presented, highlighting their potential as targets to attenuate bacterial virulence. The ongoing progress in the field of antivirulence therapy may therefore help to translate this promising concept into real intervention strategies in clinical areas. PMID:27437994

  12. Ceftaroline activity tested against contemporary Latin American bacterial pathogens (2011

    Directory of Open Access Journals (Sweden)

    Robert K. Flamm

    2014-04-01

    Full Text Available A total of 2484 target bacterial pathogens were collected (one per patient episode from patients in 16 Latin American medical centers located in seven nations during 2011. Isolate identity was confirmed at a coordinating laboratory and susceptibility testing was performed for ceftaroline and comparator agents according to reference broth microdilution methods. A total of 30.0% of isolates were from respiratory tract, 29.4% from skin and skin structure, 21.4% from blood stream, 7.9% from urinary tract and 11.3% from other sites. Ceftaroline was active againstStaphylococcus aureus (42.8% MRSA with 83.6% of the isolates at 90.0% of the non-ESBL-phenotype. The spectrum of activity of ceftaroline against pathogens from Latin America indicates that it merits further study for its potential use in the Latin American region.

  13. A bacterial pathogen infecting gametophytes of Saccharina japonica (Laminariales, Phaeophyceae)

    Institute of Scientific and Technical Information of China (English)

    PENG Yanting; LI Wei

    2013-01-01

    A newly identified bacterial disease of kelp (Saccharinajaponica) gametophytes was found in clone cultures.It is characterized by swollen gametophyte cells in the early period of infection followed by filamentous fading.An alginolytic marine bacterium referred to as A-1 was isolated from the diseased gametophytes.On the basis of 16S rDNA sequencing and morphological,physiological and biochemical characteristics,the bacterium was identified as a strain of the genus Alteromonas.By testing Koch's postulates,Alteromonas sp.A-1 was further confirmed as the pathogen.The infection process was also investigated using both scanning electron and light microscopy.

  14. Microbiological food safety issues in Brazil: bacterial pathogens.

    Science.gov (United States)

    Gomes, Bruna Carrer; Franco, Bernadette Dora Gombossy de Melo; De Martinis, Elaine Cristina Pereira

    2013-03-01

    The globalization of food supply impacts patterns of foodborne disease outbreaks worldwide, and consumers are having increased concern about microbiological food safety. In this sense, the assessment of epidemiological data of foodborne diseases in different countries has not only local impact, but it can also be of general interest, especially in the case of major global producers and exporters of several agricultural food products, such as Brazil. In this review, the most common agents of foodborne illnesses registered in Brazil will be presented, compiled mainly from official databases made available to the public. In addition, some representative examples of studies on foodborne bacterial pathogens commonly found in Brazilian foods are provided. PMID:23489044

  15. Pathogenicity of and plant immunity to soft rot pectobacteria

    Directory of Open Access Journals (Sweden)

    Pär Roland Davidsson

    2013-06-01

    Full Text Available Soft rot Pectobacteria are broad host range enterobacterial pathogens that cause disease on a variety of plant species including the major crop potato. Pectobacteria are aggressive necrotrophs that harbor a large arsenal of plant cell wall degrading enzymes as their primary virulence determinants. These enzymes together with additional virulence factors are employed to macerate the host tissue and promote host cell death to provide nutrients for the pathogens. In contrast to (hemibiotrophs such as Pseudomonas, type three secretion systems (T3SS and T3 effectors do not appear central to pathogenesis of Pectobacteria. Indeed, recent genomic analysis of several Pectobacterium species including the emerging pathogen Pectobacterium wasabiae has shown that many strains lack the entire T3SS as well as the T3 effectors. Instead, this analysis has indicated the presence of novel virulence determinants. Resistance to broad host range Pectobacteria is complex and does not appear to involve single resistance genes. Instead, activation of plant innate immunity systems including both SA and JA/ET mediated defenses appears to play a central role in attenuation of Pectobacterium virulence. These defenses are triggered by detection of pathogen-associated molecular patterns (PAMPs or recognition of modified-self such as damage-associated molecular patterns (DAMPs and result in enhancement of basal immunity (Pattern-triggered immunity, PTI. In particular plant cell-wall fragments released by the action of the degradative enzymes secreted by Pectobacteria are major players in enhanced immunity towards these pathogens. Most notably bacterial pectin degrading enzymes release oligogalacturonide (OG fragments recognized as DAMPs activating innate immune responses. Recent progress in understanding OG recognition and signaling allows novel genetic screens for OG-insensitive mutants and will provide new insights into plant defense strategies against necrotrophs such as

  16. Comparative analysis of twelve Dothideomycete plant pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Ohm, Robin; Aerts, Andrea; Salamov, Asaf; Goodwin, Stephen B.; Grigoriev, Igor

    2011-03-11

    The Dothideomycetes are one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related Dothideomycete species can have very diverse host plants. Twelve Dothideomycete genomes have currently been sequenced by the Joint Genome Institute and other sequencing centers. They can be accessed via Mycocosm which has tools for comparative analysis

  17. [RAPD analysis of plant pathogenic coryneform bacteria].

    Science.gov (United States)

    Yin, Yan-Ni; Chen, Yong-Fang; Li, Shi-Mo; Guo, Jian-Hua

    2005-12-01

    RAPD analysis was used for the taxonomy of plant pathogenic coryneform bacteria, especially for the classification of two new pathogens (Curtobacterium flaccumfaciens pv. basellae pv. nov. and Curtobacterium flaccumfaciens pv. beticola pv. nov.). 20 random primers were screened from 50 ones to detect polymorphism among the total strains used. 80.4% were polymorphic bands among the 225 ones produced. The results of pairwise similarity and UPGMA cluster analysis suggest that the two new pathovars of sugar beet (Beta vulgaris var. saccharifera) and malabar spinach (Basella rubra) are genetically close related with Curtobacterium flacumfaciens, and the minimal similarity coefficient is 0.6511. According to the RAPD analysis and previous research, some newly made taxonomic changes of the plant pathogenic coryneform bacteria are discussed. PMID:16496687

  18. Priming in plant-pathogen interactions

    NARCIS (Netherlands)

    Conrath, U.; Pieterse, C.M.J.; Mauch-Mani, B.

    2002-01-01

    Plants can acquire enhanced resistance to pathogens after treatment with necrotizing attackers, nonpathogenic root-colonizing pseudomonads, salicylic acid, β-aminobutyric acid and many other natural or synthetic compounds. The induced resistance is often associated with an enhanced capacity to mobil

  19. Bacterial food-borne pathogens in Indian food

    International Nuclear Information System (INIS)

    Food technology and food processing techniques have made tremendous advances in preservation of food and ensuring safety of food by killing food-borne pathogens. In addition to old techniques such as pasteurization, canning, dehydration, fermentation and salting, a number of new techniques such as radiation processing, high pressure technology and pulsed electric field technology are being applied for preservation of food and to ensure food safety. Total Quality Management (TQM) concepts have been developed to take care of food safety from farm to table. Hazard Analysis at Critical Control Points (HACCP) is being applied for mass scale production of food to make food free from pathogens. Despite these advances, food-borne diseases have become one of the most widespread public health problems in the world. About two thirds of all the outbreaks are traced to microbial contaminated food. According to World Health Organization (WHO) estimates, food-borne and waterborne diarrhoeal diseases kill an estimated 2 million people annually, including many children. Food safety is a major concern not only for developing countries but also for the developed countries. A number of factors such as emergence of new food-borne pathogens, development of drug resistance in pathogens, changing life style, globalization of the food supply etc. are responsible for the continuous persistence of food-borne diseases. The food-borne disease outbreaks due to E. coli O157:H7, Listeria monocytogenes, Salmonella and Campylobacter, are responsible for recall of many foods resulting in heavy losses to food industry. Due to consumer demand, a number of Ready-To-Eat (RTE) minimally processed foods are increasingly marketed; however, there is increased risk of foodborne diseases with these products. Food Technology Division of Bhabha Atomic Research Centre, Mumbai, has been working on food-borne bacterial pathogens particularly Salmonella, Campylobacter, Listeria monocytogenes, Vibrio and Aeromonasf

  20. The rhizosphere microbiome: significance of plant beneficial, plant pathogenic and human pathogenic microorganisms

    NARCIS (Netherlands)

    Mendes, R.; Garbeva, P.; Raaijmakers, J.M.

    2013-01-01

    Microbial communities play a pivotal role in the functioning of plants by influencing their physiology and development. While many members of the rhizosphere microbiome are beneficial to plant growth, also plant pathogenic microorganisms colonize the rhizosphere striving to break through the protect

  1. The rhizosphere microbiome: significance of plant beneficial, plant pathogenic, and human pathogenic microorganisms

    NARCIS (Netherlands)

    Mendes, R.; Garbeva, P.V.; Raaijmakers, J.M.

    2013-01-01

    Microbial communities play a pivotal role in the functioning of plants by influencing their physiology and development. While many members of the rhizosphere microbiome are beneficial to plant growth, also plant pathogenic microorganisms colonize the rhizosphere striving to break through the protect

  2. Genomic survey of pathogenicity determinants and VNTR markers in the cassava bacterial pathogen Xanthomonas axonopodis pv. Manihotis strain CIO151.

    Directory of Open Access Journals (Sweden)

    Mario L Arrieta-Ortiz

    Full Text Available Xanthomonas axonopodis pv. manihotis (Xam is the causal agent of bacterial blight of cassava, which is among the main components of human diet in Africa and South America. Current information about the molecular pathogenicity factors involved in the infection process of this organism is limited. Previous studies in other bacteria in this genus suggest that advanced draft genome sequences are valuable resources for molecular studies on their interaction with plants and could provide valuable tools for diagnostics and detection. Here we have generated the first manually annotated high-quality draft genome sequence of Xam strain CIO151. Its genomic structure is similar to that of other xanthomonads, especially Xanthomonas euvesicatoria and Xanthomonas citri pv. citri species. Several putative pathogenicity factors were identified, including type III effectors, cell wall-degrading enzymes and clusters encoding protein secretion systems. Specific characteristics in this genome include changes in the xanthomonadin cluster that could explain the lack of typical yellow color in all strains of this pathovar and the presence of 50 regions in the genome with atypical nucleotide composition. The genome sequence was used to predict and evaluate 22 variable number of tandem repeat (VNTR loci that were subsequently demonstrated as polymorphic in representative Xam strains. Our results demonstrate that Xanthomonas axonopodis pv. manihotis strain CIO151 possesses ten clusters of pathogenicity factors conserved within the genus Xanthomonas. We report 126 genes that are potentially unique to Xam, as well as potential horizontal transfer events in the history of the genome. The relation of these regions with virulence and pathogenicity could explain several aspects of the biology of this pathogen, including its ability to colonize both vascular and non-vascular tissues of cassava plants. A set of 16 robust, polymorphic VNTR loci will be useful to develop a multi

  3. Search for MicroRNAs Expressed by Intracellular Bacterial Pathogens in Infected Mammalian Cells

    Science.gov (United States)

    Furuse, Yuki; Finethy, Ryan; Saka, Hector A.; Xet-Mull, Ana M.; Sisk, Dana M.; Smith, Kristen L. Jurcic; Lee, Sunhee; Coers, Jörn; Valdivia, Raphael H.; Tobin, David M.; Cullen, Bryan R.

    2014-01-01

    MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin. PMID:25184567

  4. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Directory of Open Access Journals (Sweden)

    Yuki Furuse

    Full Text Available MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.

  5. Plant cell wall dynamics and wall-related susceptibility in plant–pathogen interactions

    OpenAIRE

    Bellincampi, Daniela; Cervone, Felice; Lionetti, Vincenzo

    2014-01-01

    The cell wall is a dynamic structure that often determines the outcome of the interactions between plants and pathogens. It is a barrier that pathogens need to breach to colonize the plant tissue. While fungal necrotrophs extensively destroy the integrity of the cell wall through the combined action of degrading enzymes, biotrophic fungi require a more localized and controlled degradation of the cell wall in order to keep the host cells alive and utilize their feeding structures. Also bacteri...

  6. Complete Genome Sequence of Japanese Erwinia Strain Ejp617, a Bacterial Shoot Blight Pathogen of Pear ▿

    OpenAIRE

    Park, Duck Hwan; Thapa, Shree Prasad; Choi, Beom-Soon; Kim, Won-Sik; Hur, Jang Hyun; Cho, Jun Mo; Lim, Jong-Sung; Choi, Ik-Young; Lim, Chun Keun

    2010-01-01

    The Japanese Erwinia strain Ejp617 is a plant pathogen that causes bacterial shoot blight of pear in Japan. Here, we report the complete genome sequence of strain Ejp617 isolated from Nashi pears in Japan to provide further valuable insight among related Erwinia species.

  7. Quorum sensing and bacterial pathogenicity: From molecules to disease

    Directory of Open Access Journals (Sweden)

    Antariksh Deep

    2011-01-01

    Full Text Available Quorum sensing in prokaryotic biology refers to the ability of a bacterium to sense information from other cells in the population when they reach a critical concentration (i.e. a Quorum and communicate with them. The "language" used for this intercellular communication is based on small, self-generated signal molecules called as autoinducers. Quorum sensing is thought to afford pathogenic bacteria a mechanism to minimize host immune responses by delaying the production of tissue-damaging virulence factors until sufficient bacteria have amassed and are prepared to overwhelm host defense mechanisms and establish infection. Quorum sensing systems are studied in a large number of gram-negative bacterial species belonging to α, β, and γ subclasses of proteobacteria. Among the pathogenic bacteria, Pseudomonas aeruginosa is perhaps the best understood in terms of the virulence factors regulated and the role the Quorum sensing plays in pathogenicity. Presently, Quorum sensing is considered as a potential novel target for antimicrobial therapy to control multi/all drug-resistant infections. This paper reviews Quorum sensing in gram positive and gram negative bacteria and its role in biofilm formation.

  8. Bacterial Pathogens of Ventilator Associated Pneumonia in a Tertiary Referral Hospital

    OpenAIRE

    Chi, Su Young; Kim, Tae Ok; Park, Chan Woo; Yu, Jin Yeong; Lee, Boram; Lee, Ho Sung; Kim, Yu Il; Lim, Sung Chul; Kwon, Yong Soo

    2012-01-01

    Background This study evaluates the bacterial pathogens of Ventilator-associated pneumonia (VAP) in a tertiary referral hospital. Methods A total of 109 bacterial pathogens from 91 adult patients with VAP, who were admitted to the medical intensive care unit from January 2008 to December 2009, were examined. Clinical characteristics, bacterial pathogens, and resistance profiles were analyzed. Results Staphylococcus aureus (44%) was the most frequently isolated. Acinetobacter baumanii (30%), P...

  9. Are Bacterial Volatile Compounds Poisonous Odors to a Fungal Pathogen Botrytis cinerea, Alarm Signals to Arabidopsis Seedlings for Eliciting Induced Resistance, or Both?

    OpenAIRE

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Biological control (biocontrol) agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR). Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs) are determinants for eliciting plant ISR. Eme...

  10. Role of soil, crop debris, and a plant pathogen in Salmonella enterica contamination of tomato plants.

    Directory of Open Access Journals (Sweden)

    Jeri D Barak

    Full Text Available BACKGROUND: In the U.S., tomatoes have become the most implicated vehicle for produce-associated Salmonellosis with 12 outbreaks since 1998. Although unconfirmed, trace backs suggest pre-harvest contamination with Salmonella enterica. Routes of tomato crop contamination by S. enterica in the absence of direct artificial inoculation have not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: This work examined the role of contaminated soil, the potential for crop debris to act as inoculum from one crop to the next, and any interaction between the seedbourne plant pathogen Xanthomonas campestris pv. vesicatoria and S. enterica on tomato plants. Our results show S. enterica can survive for up to six weeks in fallow soil with the ability to contaminate tomato plants. We found S. enterica can contaminate a subsequent crop via crop debris; however a fallow period between crop incorporation and subsequent seeding can affect contamination patterns. Throughout these studies, populations of S. enterica declined over time and there was no bacterial growth in either the phyllosphere or rhizoplane. The presence of X. campestris pv. vesicatoria on co-colonized tomato plants had no effect on the incidence of S. enterica tomato phyllosphere contamination. However, growth of S. enterica in the tomato phyllosphere occurred on co-colonized plants in the absence of plant disease. CONCLUSIONS/SIGNIFICANCE: S. enterica contaminated soil can lead to contamination of the tomato phyllosphere. A six week lag period between soil contamination and tomato seeding did not deter subsequent crop contamination. In the absence of plant disease, presence of the bacterial plant pathogen, X. campestris pv. vesicatoria was beneficial to S. enterica allowing multiplication of the human pathogen population. Any event leading to soil contamination with S. enterica could pose a public health risk with subsequent tomato production, especially in areas prone to bacterial spot disease.

  11. Host-pathogen interactions in plants. Plants, when exposed to oligosaccharides of fungal origin, defend themselves by accumulating antibiotics

    Energy Technology Data Exchange (ETDEWEB)

    Albersheim, P.; Valent, B.S.

    1978-01-01

    The ability to synthesize phytoalexins is a mechanism by which plants are able to stop the growth of microorganisms which have not become pathogenic on the phytoalexin-producing plant. Although not sufficient for its complete resistence to pathogens, an ability to synthesize phytoalexins is likely to be one essential criterion for a plant to be resistant to pathogens. Plants recognize the presence of many nonpathogenic fungi by recognizing a structural component of the mycelial walls of the fungi. Other microorganisms do not have structural glucans in their walls. There is, likely, some other components of bacteria, for instance, which act as elicitors in plants since it is known that they do elicit phytoalexin production in plants. The authors are attempting to identify a bacterial elicitor. It is known that the soybean pathogen Phytophthora magasperma is an oligosaccharide composed only of glucose. This is of general biological interest since it shows that oligosaccharides can act as regulatory molecules.

  12. Bacterial Gibberellins Induce Systemic Resistance of Plants

    OpenAIRE

    I. N. FEKLISTOVA; I. A. GRINEVA; T. L. SKAKUN; L. E. SADOVSKAYA

    2014-01-01

    It is generally agreed today that some rhizosphere bacteria can ensure induced systemic resistance to pathogens. In this paper we tested the ability of gibberellins produced by rhizosphere non-pathogenic bacteria Pseudomonas aurantiaca to induce systemic resistance to alternariosis agent – Alternaria brassicicola – in oilseed rape plants.Oilseed rape (Brássica nápus) is one of the most promising oil-bearing croppers. It allows improving the supply of population with vegetable oil, animal and ...

  13. Diet and environment shape fecal bacterial microbiota composition and enteric pathogen load of grizzly bears.

    Directory of Open Access Journals (Sweden)

    Clarissa Schwab

    Full Text Available BACKGROUND: Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic clostridia in wild and captive grizzly bears (Ursus arctos and relates these to food resources consumed by bears. METHODOLOGY/PRINCIPAL FINDINGS: Feces were obtained from animals of two wild populations and from two captive animals during an active bear season. Wild animals consumed a diverse diet composed of plant material, animal prey and insects. Captive animals were fed a regular granulated diet with a supplement of fruits and vegetables. Bacterial populations were analyzed using quantitative PCR. Fecal microbiota composition fluctuated in wild and in captive animals. The abundance of Clostridium clusters I and XI, and of C. perfringens correlated to regular diet protein intake. Enteroaggregative E. coli were consistently present in all populations. The C. sordellii phospholipase C was identified in three samples of wild animals and for the first time in Ursids. CONCLUSION: This is the first longitudinal study monitoring the fecal microbiota of wild carnivores and comparing it to that of captive individuals of the same species. Location and diet affected fecal bacterial populations as well as the presence of enteric pathogens.

  14. Plant Pathogen Sensing for Early Disease Control

    OpenAIRE

    Heard, Stephanie

    2014-01-01

    Sclerotinia sclerotiorum, a fungal pathogen of over 400 plant species has been estimated to cost UK based farmers approximately £20 million per year during severe outbreak (Oerke and Dehne 2004). S. sclerotiorum disease incidence is difficult to predict as outbreaks are often sporadic. Ascospores released from the fruiting bodies or apothecia can be dispersed for tens of kilometres. This makes disease control problematic and with no S. sclerotiorum resistant varieties available, growers are...

  15. Removal of pathogenic bacterial biofilms by combinations of oxidizing compounds.

    Science.gov (United States)

    Olmedo, Gabriela María; Grillo-Puertas, Mariana; Cerioni, Luciana; Rapisarda, Viviana Andrea; Volentini, Sabrina Inés

    2015-05-01

    Bacterial biofilms are commonly formed on medical devices and food processing surfaces. The antimicrobials used have limited efficacy against the biofilms; therefore, new strategies to prevent and remove these structures are needed. Here, the effectiveness of brief oxidative treatments, based on the combination of sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) in the presence of copper sulfate (CuSO4), were evaluated against bacterial laboratory strains and clinical isolates, both in planktonic and biofilm states. Simultaneous application of oxidants synergistically inactivated planktonic cells and prevented biofilm formation of laboratory Escherichia coli, Salmonella enterica serovar Typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus strains, as well as clinical isolates of Salmonella enterica subsp. enterica, Klebsiella oxytoca, and uropathogenic E. coli. In addition, preformed biofilms of E. coli C, Salmonella Typhimurium, K. pneumoniae, and Salmonella enterica exposed to treatments were removed by applying 12 mg/L NaClO, 0.1 mmol/L CuSO4, and 350 mmol/L H2O2 for 5 min. Klebsiella oxytoca and Staphylococcus aureus required a 5-fold increase in NaClO concentration, and the E. coli clinical isolate remained unremovable unless treatments were applied on biofilms formed within 24 h instead of 48 h. The application of treatments that last a few minutes using oxidizing compounds at low concentrations represents an interesting disinfection strategy against pathogens associated with medical and industrial settings. PMID:25864510

  16. Comparative analysis of two emerging rice seed bacterial pathogens.

    Science.gov (United States)

    Fory, P A; Triplett, L; Ballen, C; Abello, J F; Duitama, J; Aricapa, M G; Prado, G A; Correa, F; Hamilton, J; Leach, J E; Tohme, J; Mosquera, G M

    2014-05-01

    Seed sterility and grain discoloration limit rice production in Colombia and several Central American countries. In samples of discolored rice seed grown in Colombian fields, the species Burkholderia glumae and B. gladioli were isolated, and field isolates were compared phenotypically. An artificial inoculation assay was used to determine that, although both bacterial species cause symptoms on rice grains, B. glumae is a more aggressive pathogen, causing yield reduction and higher levels of grain sterility. To identify putative virulence genes differing between B. glumae and B. gladioli, four previously sequenced genomes of Asian and U.S. strains of the two pathogens were compared with each other and with two draft genomes of Colombian B. glumae and B. gladioli isolates generated for this study. Whereas previously characterized Burkholderia virulence factors are highly conserved between the two species, B. glumae and B. gladioli strains are predicted to encode distinct groups of genes encoding type VI secretion systems, transcriptional regulators, and membrane-sensing proteins. This study shows that both B. glumae and B. gladioli can threaten grain quality, although only one species affects yield. Furthermore, genotypic differences between the two strains are identified that could contribute to disease phenotypic differences. PMID:24261408

  17. Advances in genetic manipulation of obligate intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Paul eBeare

    2011-05-01

    Full Text Available Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the α-proteobacterial genera Anaplasma, Ehrlichia, Orientia and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera.

  18. Antimicrobial Effects of Quercus Brantii Fruits on Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Issa Sadeghian

    2012-08-01

    Full Text Available Background: In recent years, a number of antibiotics have lost their effectiveness due to the development of resistant strains, mostly through the expression of resistance genes.Objectives: The aim of the present study was to investigate the antimicrobial property of Quercus brantii fruits and compare its effects with some current antibiotics.Materials and Methods: The antimicrobial activities of an ethanol extract of Q. brantii (Oak fruits (brown cortex: B.C and white core: W.C were tested in vitro against eight reference strains of enteric pathogenic bacteria. The antimicrobial activities of the extracts were examined based on the disc diffusion method. The results were evaluated as inhibition zones around the discs impregnated with B.C and W.C extracts at different concentrations (2 to 10 %.Results: The antibacterial effect of the B.C ethanolic extract on Escherichia coli was significant and had a concentration-related effect, although there was no significant effect found on Helicobacter pylori. The W.C ethanolic extract has a high antimicrobial effect on Streptococcus pyogenes; at the same time significant antibacterial activity occurred against H pylori. Comparisons between the antimicrobial activities of these extracts (B.C and W.C and standard antibiotics; gentamicin, colistin, and methicillin, showed that in the most commonly tested bacteria the antibacterial activity of these extracts was even greater than with the antibiotics. Analysis of the extracts components by gas chromatography, showed that tannins and phenolic compounds could be responsible for these antimicrobial activities.Conclusions: The results of this study showed that different parts of Q. brantii have antimicrobial activity against gastrointestinal bacterial pathogens. These antimicrobial activities, in almost all cases, were greater than with standard antibiotics..--------------------------------------------------------------------------------Implication for health

  19. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Science.gov (United States)

    Narusaka, Mari; Minami, Taichi; Iwabuchi, Chikako; Hamasaki, Takashi; Takasaki, Satoko; Kawamura, Kimito; Narusaka, Yoshihiro

    2015-01-01

    Housaku Monogatari (HM) is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA) pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods. PMID:25565273

  20. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

    Directory of Open Access Journals (Sweden)

    Mari Narusaka

    Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

  1. The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.

    Science.gov (United States)

    Han, Qin; Wu, Fengli; Wang, Xiaonan; Qi, Hong; Shi, Liang; Ren, Ang; Liu, Qinghai; Zhao, Mingwen; Tang, Canming

    2015-04-01

    Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V. dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V. dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V. dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V. dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V. dahliae. PMID:24934960

  2. The Venturia Apple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

    OpenAIRE

    Gopaljee Jha; Karnika Thakur; Priyanka Thakur

    2009-01-01

    Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

  3. Colonization of plants by human pathogenic bacteria in the course of organic vegetable production

    OpenAIRE

    AndreasHofmann

    2014-01-01

    In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identi...

  4. Assessment of bacterial pathogens in fresh rainwater and airborne particulate matter using Real-Time PCR

    Science.gov (United States)

    Kaushik, Rajni; Balasubramanian, Rajasekhar

    2012-01-01

    Bacterial pathogens in airborne particulate matter (PM) and in rainwater (RW) were detected using a robust and sensitive Real-Time PCR method. Both RW and PM were collected simultaneously in the tropical atmosphere of Singapore, which were then subjected to analysis for the presence of selected bacterial pathogens and potential pathogen of health concern ( Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Aeromonas hydrophila). These pathogens were found to be prevalent in both PM and RW samples with E. coli being the most prevalent potential pathogen in both types of samples. The temporal distribution of these pathogens in PM and RW was found to be similar to each other. Using the proposed microbiological technique, the atmospheric deposition (dry and wet deposition) of bacterial pathogens to lakes and reservoirs can be studied in view of growing concerns about the outbreak of waterborne diseases.

  5. Phytohormone mediation of interactions between herbivores and plant pathogens.

    Science.gov (United States)

    Lazebnik, Jenny; Frago, Enric; Dicke, Marcel; van Loon, Joop J A

    2014-07-01

    Induced plant defenses against either pathogens or herbivore attackers are regulated by phytohormones. These phytohormones are increasingly recognized as important mediators of interactions between organisms associated with plants. In this review, we discuss the role of plant defense hormones in sequential tri-partite interactions among plants, pathogenic microbes, and herbivorous insects, based on the most recent literature. We discuss the importance of pathogen trophic strategy in the interaction with herbivores that exhibit different feeding modes. Plant resistance mechanisms also affect plant quality in future interactions with attackers. We discuss exemplary evidence for the hypotheses that (i) biotrophic pathogens can facilitate chewing herbivores, unless plants exhibit effector-triggered immunity, but (ii) facilitate or inhibit phloem feeders. (iii) Necrotrophic pathogens, on the other hand, can inhibit both phloem feeders and chewers. We also propose herbivore feeding mode as predictor of effects on pathogens of different trophic strategies, providing evidence for the hypotheses that (iv) phloem feeders inhibit pathogen attack by increasing SA induction, whereas (v) chewing herbivores tend not to affect necrotrophic pathogens, while they may either inhibit or facilitate biotrophic pathogens. Putting these hypotheses to the test will increase our understanding of phytohormonal regulation of plant defense to sequential attack by plant pathogens and insect herbivores. This will provide valuable insight into plant-mediated ecological interactions among members of the plant-associated community. PMID:25059974

  6. Plant pathogen-induced volatiles attract parasitoids to increase parasitism of an insect vector

    Directory of Open Access Journals (Sweden)

    Xavier eMartini

    2014-05-01

    Full Text Available Interactions between plant pathogens and arthropods have been predominantly studied through the prism of herbivorous arthropods. Currently, little is known about the effect of plant pathogens on the third trophic level. This question is particularly interesting in cases where pathogens manipulate host phenotype to increase vector attraction and presumably increase their own proliferation. Indeed, a predator or a parasitoid of a vector may take advantage of this manipulated phenotype to increase its foraging performance. We explored the case of a bacterial pathogen, Candidatus Liberibacter asiaticus (Las, which modifies the odors released by its host plant (citrus trees to attract its vector, the psyllid Diaphorina citri. We found that the specialist parasitoid of D. citri, Tamarixia radiata, was attracted more toward Las-infected than uninfected plants. We demonstrated that this attractiveness was due to the release of methyl salicylate. Parasitization of D. citri nymphs on Las-infected plants was higher than on uninfected controls. Also, parasitization was higher on uninfected plants baited with methyl salicylate than on non-baited controls. This is the first report of a parasitoid ‘eavesdropping’ on a plant volatile induced by bacterial pathogen infection, which also increases effectiveness of host seeking behavior of its herbivorous vector.

  7. Effect of certain medicinal plants extracts on some pathogenic microorganisms

    International Nuclear Information System (INIS)

    A queous, alcoholic and active ingredients extracts of karkatde, tamarind and licorice showed different inhibitory effects on the growth of some pathogenic srains. Active ingredients wwere the most effective on bacterial strains than alcoholic and aqueous extracts. Extracts of karkade and tamarind were more effective on diplococcus sp. and pseudomonas aeruginosa, respectively than other bacterial strains under investigation and the minimum inhibitory concentration (MIC) were 2 mu1/6 mm diameter disc. The extracts of karkade, tamarind and licorice increased the mycelial dry weight of aspergillus flavus by increasing the concentration of extracts in the media. Effect of extracted substances of tested plants on the ultra-structure of diplococcus sp. and p. aeruginosa and the changes in the morphological changes of A. flovus aflatoxin producer strain were studied by using electron and light microscopes, respectively. The treatment of p. aeruginosa with MIC (2 mu 1 ) of tamarined extract induced rupture of cell wall lysis of cytoplasmic ocntent. However, treatment of diplococcus sp. with 2 mu 1 of karkade extract caused patial rupture of cell wall while cell content still keeping its normal pattern. On the other hand, licorice extract stimulated germination of spores of A. Flavus.Total protein and carbohydrate contents of diplococcus sp., and p. aeruginosa decreased as a result of inhibition effect of active substance on bacterial cells. While, in A. flavus, it increased as a result of the stimulation effect of licorice extract on fungal spores

  8. Comparative analysis of glutaredoxin domains from bacterial opportunistic pathogens

    International Nuclear Information System (INIS)

    NMR structures of the glutaredoxin (GLXR) domains from Br. melitensis and Ba. henselae have been determined as part of the SSGCID initiative. Comparison of the domains with known structures reveals overall structural similarity between these proteins and previously determined E. coli GLXR structures, with minor changes associated with the position of helix 1 and with regions that diverge from similar structures found in the closest related human homolog. Glutaredoxin proteins (GLXRs) are essential components of the glutathione system that reductively detoxify substances such as arsenic and peroxides and are important in the synthesis of DNA via ribonucleotide reductases. NMR solution structures of glutaredoxin domains from two Gram-negative opportunistic pathogens, Brucella melitensis and Bartonella henselae, are presented. These domains lack the N-terminal helix that is frequently present in eukaryotic GLXRs. The conserved active-site cysteines adopt canonical proline/tyrosine-stabilized geometries. A difference in the angle of α-helix 2 relative to the β-sheet surface and the presence of an extended loop in the human sequence suggests potential regulatory regions and/or protein–protein interaction motifs. This observation is consistent with mutations in this region that suppress defects in GLXR–ribonucleotide reductase interactions. These differences between the human and bacterial forms are adjacent to the dithiol active site and may permit species-selective drug design

  9. Bacterial biofilm formation, pathogenicity, diagnostics and control: An overview

    Directory of Open Access Journals (Sweden)

    Sawhney Rajesh

    2009-07-01

    Full Text Available Bacterial biofilms are complex, mono- or poly-microbialn communities adhering to biotic or abiotic surfaces. This adaptation has been implicated as a survival strategy. The formation of biofilms is mediated by mechanical, biochemical and genetical factors. The biofilms enhance the virulence of the pathogen and have their potential role in various infections, such as dental caries, cystic fibrosis, osteonecrosis, urinary tract infection and eye infections. A number of diagnostic techniques, viz., bright-field microscopy, epifluorescence microscopy, scanning electron microscopy, confocal laser scanning microscopy and amplicon length heterogeneity polymerase chain reaction, have been employed for detection of these communities. Researchers have worked on applications of catheter lock solutions, a fish protein coating, acid shock treatment, susceptibility to bacteriophages, etc., for biofilm control. However, we need to rearrange our strategies to have thorough insight and concentrate on priority basis to develop new accurate, precise and rapid diagnostic protocols for detection and evaluation of biofilm. Above all, the strict compliance to these techniques is required for accurate diagnosis and control.

  10. A membrane-bound matrix-metalloproteinase from Nicotiana tabacum cv. BY-2 is induced by bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Wahner Verena

    2009-06-01

    Full Text Available Abstract Background Plant matrix metalloproteinases (MMP are conserved proteolytic enzymes found in a wide range of monocotyledonous and dicotyledonous plant species. Acting on the plant extracellular matrix, they play crucial roles in many aspects of plant physiology including growth, development and the response to stresses such as pathogen attack. Results We have identified the first tobacco MMP, designated NtMMP1, and have isolated the corresponding cDNA sequence from the tobacco suspension cell line BY-2. The overall domain structure of NtMMP1 is similar to known MMP sequences, although certain features suggest it may be constitutively active rather than dependent on proteolytic processing. The protein appears to be expressed in two forms with different molecular masses, both of which are enzymatically active as determined by casein zymography. Exchanging the catalytic domain of NtMMP1 with green fluorescent protein (GFP facilitated subcellular localization by confocal laser scanning microscopy, showing the protein is normally inserted into the plasma membrane. The NtMMP1 gene is expressed constitutively at a low level but can be induced by exposure to bacterial pathogens. Conclusion Our biochemical analysis of NtMMP1 together with bioinformatic data on the primary sequence indicate that NtMMP1 is a constitutively-active protease. Given its induction in response to bacterial pathogens and its localization in the plasma membrane, we propose a role in pathogen defense at the cell periphery.

  11. Screening of Quercus infectoria gall extracts as anti-bacterial agents against dental pathogens

    Directory of Open Access Journals (Sweden)

    Vermani Archa

    2009-01-01

    Full Text Available Background and Objectives: A number of bacteria have now become antibiotic-resistant. This increases the importance of ayurvedic drugs. We report, here, the activity of different extracts (petroleum ether, chloroform, methanol and water of Quercus infectoria galls against dental pathogens - Streptococcus mutans, Streptococcus salivarius, Staphylococcus aureus, Lactobacillus acidophilus (designated and Streptococcus sanguis (isolated. Materials and Methods: The cup-plate method was used in anti-bacterial activity of the extracts at concentration of 200 mg/ml against dental pathogens. Minimum inhibitory concentration (MIC values of most effective extracts against the most susceptible bacteria were determined using a two-fold serial micro dilution method. Results: Methanolic extract showed maximum anti-bacterial activity against all the bacteria. The most susceptible bacteria were S. sanguis followed by S. aureus, S. mutans, S. salivarius and L. acidophilus. The MIC values showed that methanolic extract was more effective than water extract. Conclusion: The plant has the potential to generate herbal metabolites. The crude extracts demonstrating anti-dental caries activity could result in the discovery of new chemical classes of antibiotics. These chemical classes of antibiotics could serve as selective agents for the maintenance of human health and provide bio-chemical tools for the study of infectious diseases.

  12. Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

    OpenAIRE

    Wang, Lipu; Fobert, Pierre R.

    2013-01-01

    During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae . Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), f...

  13. Global Regulation of Virulence Determinants During Plant Colonization in the Bacterial Phytopathogen, Pantoea stewartii subsp. stewartii

    OpenAIRE

    Burbank, Lindsey

    2014-01-01

    Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a bacterial pathogen of sweet corn which colonizes both the apoplast and xylem tissues. During the initial stages of the infection process, the pathogen forms water-soaked lesions through lysis of the plant cells, followed by colonization of the xylem tissue where it can grow to high cell densities and form biofilms. Biofilm formation within the xylem vessels can block water flow, causing the characteristic wiltin...

  14. Sharing of quorum-sensing signals and role of interspecies communities in a bacterial plant disease

    OpenAIRE

    Hosni, Taha; Moretti, Chiaraluce; Devescovi, Giulia; Suarez-Moreno, Zulma Rocio; Fatmi, M' Barek; Guarnaccia, Corrado; Pongor, Sandor; Onofri, Andrea; Buonaurio, Roberto; Venturi, Vittorio

    2011-01-01

    Pathogenic bacteria interact not only with the host organism but most probably also with the resident microbial flora. In the knot disease of the olive tree (Olea europaea), the causative agent is the bacterium Pseudomonas savastanoi pv. savastanoi (Psv). Two bacterial species, namely Pantoea agglomerans and Erwinia toletana, which are not pathogenic and are olive plant epiphytes and endophytes, have been found very often to be associated with the olive knot. We identified the chemical signal...

  15. Bacterial respiratory pathogens in children with inherited immune and airway disorders: nasopharyngeal carriage and disease risk

    NARCIS (Netherlands)

    Verhagen, L.M.; Luesink, M.; Warris, A.; Groot, R. de; Hermans, P.W.M.

    2013-01-01

    Children with primary immunodeficiencies, sickle cell disease and cystic fibrosis are at risk to develop invasive bacterial infections caused by respiratory tract pathogens, in particular Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. This review article evaluates the ro

  16. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice

    Science.gov (United States)

    Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392

  17. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice.

    Science.gov (United States)

    Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392

  18. Colonization of plants by human pathogenic bacteria in the course of organic vegetable production.

    Science.gov (United States)

    Hofmann, Andreas; Fischer, Doreen; Hartmann, Anton; Schmid, Michael

    2014-01-01

    In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system) or via agricultural soil amended with spiked organic fertilizers (soil system). In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH) was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4 × 10 CFU/ml in the axenic system or 4 × 10(5) CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in some

  19. Colonization of plants by human pathogenic bacteria in the course of organic vegetable production

    Directory of Open Access Journals (Sweden)

    AndreasHofmann

    2014-05-01

    Full Text Available In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system or via agricultural soil amended with spiked organic fertilizers (soil system. In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4x10CFU/ml in the axenic system or 4x105CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in

  20. Inhibitory Effect of Lactobacillus reuteri on Some Pathogenic Bacteria Isolated From Women With Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Eslami

    2014-08-01

    Full Text Available Background Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. Objectives The purpose of this study was to investigate the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria isolated from women with bacterial vaginosis. Materials and Methods Ninety-six samples were obtained from vaginal discharge of women with bacterial vaginosis by a gynecologist with a Dacron swab and put in sterile tubes containing TSB broth and Thioglycollate broth. Then were immediately sent to the laboratory in cold chain for further assessment. Afterward, culture was transferred on blood agar, EMB, Palcam and differential diagnosis environments. Then cultures were incubated for 24 hours at 37 °C. Lactobacillus reuteri strains were cultured in MRS environment and transferred to laboratory. After purification of pathogenic bacteria, Lactobacillus reuteri inhibitory effect on pathogenic bacteria was evaluated by minimum inhibitory concentration (MIC and antibiogram. Statistical analysis was performed using SPSS software v.16. Results The results of this study demonstrated the inhibitory effect of Lactobacillus reuteri on some pathogenic bacteria that cause bacterial, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae, Enterococcus, Listeria monocytogenes and E. coli. Microscopic examination of stained smears of most Lactobacillus and pathogenic bacteria showed reduced. The prevalence of abnormal vaginal discharge, history of drug use, contraceptive methods and douching were 61%, 55%, 42% and 13%, respectively. Significant difference was observed between the use and non-use of IUD in women with bacterial. Conclusions Our findings indicated the inhibitory effect of Lactobacillus reuteri on pathogenic bacteria that

  1. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Young [National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada)], E-mail: daeyoung.lee@ec.gc.ca; Lauder, Heather; Cruwys, Heather; Falletta, Patricia [National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada); Beaudette, Lee A. [Environmental Science and Technology Centre, Environment Canada, 335 River Road South, Ottawa, Ontario, K1A 0H3 (Canada)], E-mail: lee.beaudette@ec.gc.ca

    2008-07-15

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 10{sup 3}A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater.

  2. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens

    International Nuclear Information System (INIS)

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 103A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater

  3. Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens.

    Science.gov (United States)

    Lee, Dae-Young; Lauder, Heather; Cruwys, Heather; Falletta, Patricia; Beaudette, Lee A

    2008-07-15

    Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences. To date, 62 probes have been designed against 38 species, 4 genera, and 1 family of pathogens. The detection sensitivity of the microarray for a waterborne pathogen Aeromonas hydrophila was determined to be approximately 1.0% of the total DNA, or approximately 10(3)A. hydrophila cells per sample. The efficacy of the DNA microarray was verified in a parallel study where pathogen genes and E. coli cells were enumerated using real-time quantitative PCR (qPCR) and standard membrane filter techniques, respectively. The microarray and qPCR successfully detected multiple wastewater pathogen species at different stages of the disinfection process (i.e. secondary effluents vs. disinfected final effluents) and at two treatment plants employing different disinfection methods (i.e. chlorination vs. UV irradiation). This result demonstrates the effectiveness of the DNA microarray as a semi-quantitative, high throughput pathogen monitoring tool for municipal wastewater. PMID:18423816

  4. Bacterial contamination of platelet concentrates: pathogen detection and inactivation methods

    Directory of Open Access Journals (Sweden)

    Dana Védy

    2009-04-01

    Full Text Available Whereas the reduction of transfusion related viral transmission has been a priority during the last decade, bacterial infection transmitted by transfusion still remains associated to a high morbidity and mortality, and constitutes the most frequent infectious risk of transfusion. This problem especially concerns platelet concentrates because of their favorable bacterial growth conditions. This review gives an overview of platelet transfusion-related bacterial contamination as well as on the different strategies to reduce this problem by using either bacterial detection or inactivation methods.

  5. ANTIMICROBIAL ACTIVITY OF SOME MEDICINAL HERBAL EXTRACTS ON CLINICALLY IMPORTANT BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    J. Suriya et al.

    2012-01-01

    Full Text Available The antibacterial activity of methanol extract of Abutilon indicum, Hygrophila spinosa and Mimosa pudica were studied by agar well diffusion method in vitro. The effect of antibacterial potential was examined against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Proteus vulgaris, Enterococcus faecalis, Klebsiella pneumoniae, Vibrio cholerae, Salmonella typhi and Salmonella paratyphi. The methanol extract of these medicinal plants have showed consistently significant inhibitory activity on different bacterial pathogens tested. Furthermore, the Minimum Inhibitory Concentration (MIC studies carried out by broth dilution assay and found the MIC ranged between 0.2 to 0.9mg/ml. Overall the methanol extracts was found to be more effective. The results of the extracts were compared with the standard antibiotics Kanamycin.

  6. The Venturia Apple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

    Directory of Open Access Journals (Sweden)

    Gopaljee Jha

    2009-01-01

    Full Text Available Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

  7. Antagonism of Some Aquatic Hyphomycetes against Plant Pathogenic Fungi

    OpenAIRE

    S. C. SATI; P. Arya

    2010-01-01

    The antagonistic activity of five aquatic hyphomycetes, viz., Heliscus lugdunensis, Tetrachaetum elegans, Tetracladium breve, T. marchalianum, and T. nainitalense, against seven plant pathogenic fungi was studied using a dual culture technique. Inhibitory activity of tested aquatic hyphomycetes was determined by measuring the radial growth of plant pathogenic fungi on dual culture plates. Tetrachaetum elegans showed antagonistic activity against Colletotrichum falcatum, Fusarium oxysporum, Py...

  8. The top 10 oomycete pathogens in molecular plant pathology

    Science.gov (United States)

    Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens that threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant pathogenic oomycete taxa based on scientific and economic importance. In total, ...

  9. Insights into Cross-Kingdom Plant Pathogenic Bacteria

    OpenAIRE

    Morgan W B Kirzinger; John Stavrinides; Geetanchaly Nadarasah

    2011-01-01

    Plant and human pathogens have evolved disease factors to successfully exploit their respective hosts. Phytopathogens utilize specific determinants that help to breach reinforced cell walls and manipulate plant physiology to facilitate the disease process, while human pathogens use determinants for exploiting mammalian physiology and overcoming highly developed adaptive immune responses. Emerging research, however, has highlighted the ability of seemingly dedicated human pathogens to cause pl...

  10. Selective Media for In Vitro Activity Evaluation of Bacterial Biocontrol Against Pathogenic Vibrio

    OpenAIRE

    ALIM ISNANSETYO; MUHTADI; INDAH ISTIQOMAH; KAMISO HANDOYO NITIMULYO; TRIYANTO

    2011-01-01

    In vitro activity test is a critical evaluation to screen the potential biocontrol agent. We developed a selective medium for quantitative in vitro activity evaluation of bacterial biocontrol agents against pathogenic Vibrio in aquaculture. Sensitivity test of bacterial biocontrol and Vibrio spp. to nine antibiotics showed that oxytetracycline inhibited the growth of Vibrio spp., but did not inhibit the growth of the bacterial biocontrol. This selective inhibition activity of oxytetracycline ...

  11. Bacterial ‘Cell’ Phones: Do cell phones carry potential pathogens?

    OpenAIRE

    Kiran Chawla; Chiranjay Mukhopadhayay; Bimala Gurung; Priya Bhate; Indira Bairy

    2009-01-01

    Cell phones are important companions for professionals especially health care workers (HCWs) for better communication in hospital. The present study compared the nature of the growth of potentially pathogenic bacterial flora on cell phones in hospital and community. 75% cell phones from both the categories grew at least one potentially pathogenic organism. Cell phones from HCWs grew significantly more potential pathogens like MRSA (20%), Acinetobacter species (5%), Pseudomonas species (2.5%) ...

  12. Are bacterial volatile compounds poisonous odors to a fungal pathogen Botrytis cinerea, alarm signals to Arabidopsis seedlings for eliciting induced resistance, or both?

    Directory of Open Access Journals (Sweden)

    Choong-Min eRyu

    2016-02-01

    Full Text Available Biological control (biocontrol agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR. Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 hours post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen

  13. Are Bacterial Volatile Compounds Poisonous Odors to a Fungal Pathogen Botrytis cinerea, Alarm Signals to Arabidopsis Seedlings for Eliciting Induced Resistance, or Both?

    Science.gov (United States)

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Biological control (biocontrol) agents act on plants via numerous mechanisms, and can be used to protect plants from pathogens. Biocontrol agents can act directly as pathogen antagonists or competitors or indirectly to promote plant induced systemic resistance (ISR). Whether a biocontrol agent acts directly or indirectly depends on the specific strain and the pathosystem type. We reported previously that bacterial volatile organic compounds (VOCs) are determinants for eliciting plant ISR. Emerging data suggest that bacterial VOCs also can directly inhibit fungal and plant growth. The aim of the current study was to differentiate direct and indirect mechanisms of bacterial VOC effects against Botrytis cinerea infection of Arabidopsis. Volatile emissions from Bacillus subtilis GB03 successfully protected Arabidopsis seedlings against B. cinerea. First, we investigated the direct effects of bacterial VOCs on symptom development and different phenological stages of B. cinerea including spore germination, mycelial attachment to the leaf surface, mycelial growth, and sporulation in vitro and in planta. Volatile emissions inhibited hyphal growth in a dose-dependent manner in vitro, and interfered with fungal attachment on the hydrophobic leaf surface. Second, the optimized bacterial concentration that did not directly inhibit fungal growth successfully protected Arabidopsis from fungal infection, which indicates that bacterial VOC-elicited plant ISR has a more important role in biocontrol than direct inhibition of fungal growth on Arabidopsis. We performed qRT-PCR to investigate the priming of the defense-related genes PR1, PDF1.2, and ChiB at 0, 12, 24, and 36 h post-infection and 14 days after the start of plant exposure to bacterial VOCs. The results indicate that bacterial VOCs potentiate expression of PR1 and PDF1.2 but not ChiB, which stimulates SA- and JA-dependent signaling pathways in plant ISR and protects plants against pathogen colonization. This study

  14. In-vitro Antibacterial Efficacy of Solvent Extracts of Leaves of Bauhinia racemosa Lam. (Caesalpiniaceae Against Enteric Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    S. B. Dahikar

    2011-01-01

    Full Text Available Phytochemical screening of the plant leaves reveals the presence of carbohydrates, alkaloids, flavonoids, steroids, and tannins. Petroleum ether extract, chloroform extract, ethyl acetate extract and methanol extracts of leaves of Bauhinia racemosa Linn. were prepared and antibacterial activity were studied by disc diffusion method against certain enteric bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Enterobacter aerogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Salmonella typhi, Staphylococcus epidermidis and Proteus vulgaris. The Methanol extracts had wide range of antibacterial activity against enteric bacterial pathogens than the petroleum ether extract, where as ethyl acetate extract were slightly higher antibacterial activity than chloroform extract. Antibacterial activity of various extract of leaves of Bauhinia racemosa was carried in attempt to develop a new pharmaceutical drug from natural origin for prevention of enteric infection.

  15. Getting to PTI of bacterial RNAs: Triggering plant innate immunity by extracellular RNAs from bacteria.

    Science.gov (United States)

    Park, Yong-Soon; Lee, Boyoung; Ryu, Choong-Min

    2016-07-01

    Defense against diverse biotic and abiotic stresses requires the plant to distinguish between self and non-self signaling molecules. Pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) are pivotal for triggering innate immunity in plants. Unlike in animals and humans, the precise roles of nucleic acids in plant innate immunity are unclear. We therefore investigated the effects of infiltration of total Pseudomonas syringae pv. tomato DC3000 (Pto DC3000) RNAs into Arabidopsis plants. The pathogen population was 10-fold lower in bacterial RNAs pre-treated Arabidopsis plants than in the control. Bacterial RNAs purity was confirmed by physical (sonication) and chemical (RNase A and proteinase K digestion) methods. The perception of bacterial RNAs, especially rRNAs, positively regulated mitogen-activated protein kinase (MAPK) and induced a reactive oxygen species burst, callose deposition, salicylic acid (SA) and jasmonic acid (JA) signaling, and defense-related genes. Therefore, bacterial RNAs function as a new MAMP that activates plant innate immunity, providing a new paradigm for plant-microbe interactions. PMID:27301792

  16. Dancing with the Stars: How Choreographed Bacterial Interactions Dictate Nososymbiocity and Give Rise to Keystone Pathogens, Accessory Pathogens, and Pathobionts.

    Science.gov (United States)

    Hajishengallis, George; Lamont, Richard J

    2016-06-01

    Many diseases that originate on mucosal membranes ensue from the action of polymicrobial communities of indigenous organisms working in concert to disrupt homeostatic mechanisms. Multilevel physical and chemical communication systems among constituent organisms underlie polymicrobial synergy and dictate the community's pathogenic potential or nososymbiocity, that is, disease arising from living together with a susceptible host. Functional specialization of community participants, often originating from metabolic codependence, has given rise to several newly appreciated designations within the commensal-to-pathogen spectrum. Accessory pathogens, while inherently commensal in a particular microenvironment, nonetheless enhance the colonization or metabolic activity of pathogens. Keystone pathogens (bacterial drivers or alpha-bugs) exert their influence at low abundance by modulating both the composition and levels of community participants and by manipulating host responses. Pathobionts (or bacterial passengers) exploit disrupted host homeostasis to flourish and promote inflammatory disease. In this review we discuss how commensal or pathogenic properties of organisms are not intrinsic features, and have to be considered within the context of both the microbial community in which they reside and the host immune status. PMID:26968354

  17. Universal primer PCR with DGGE for rapid detection of bacterial pathogens.

    Science.gov (United States)

    Ji, Niannian; Peng, Bo; Wang, Guizhong; Wang, Sanying; Peng, Xuanxian

    2004-06-01

    A universal primer PCR (UPPCR) combined with denaturing gradient gel electrophoresis (DGGE) was evaluated as a method permitting the rapid detection of pathogens. The results show that this method is efficient at amplifying the conserved regions of bacterial 16S rRNA genes with universal primers and can detect causative bacterial pathogens rapidly. Six species of bacteria from fisheries (Pseudomonas fluorescens, Vibrio anguillarum, Aeromonas hydrophila, Vibrio fluvialis, Providencia rettgeri and Aeromonas sobria) were examined. Our results indicate that the approach we undertook can be adopted not only for axenic bacterial populations but also for mixed communities as well. Furthermore, we were able to achieve the rapid detection of multiple bacteria a single in sample. In addition, UPPCR-DGGE was shown to be better than previously reported UPPCR-single-stranded conformation polymorphism (SSCP)-based methods for the rapid detection of bacterial pathogens. PMID:15134888

  18. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    Directory of Open Access Journals (Sweden)

    Derrick E Fouts

    2016-02-01

    Full Text Available Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1 the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2 genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12 autotrophy as a bacterial virulence factor; 3 CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4 finding Leptospira pathogen-specific specialized protein secretion systems; 5 novel virulence-related genes/gene families such as the Virulence Modifying (VM (PF07598 paralogs proteins and pathogen-specific adhesins; 6 discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7 and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately

  19. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    Science.gov (United States)

    Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M

    2016-02-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  20. Pathogen infection drives patterns of nutrient resorption in citrus plants

    OpenAIRE

    Jirong Cao; Chunzhen Cheng; Junjie Yang; Qibing Wang

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen ‘Candidatus Liberibacter asiaticus’ grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of ‘Ca. L. asiaticus’ infection on nit...

  1. Surface Proteoglycans as Mediators in Bacterial Pathogens Infections

    Science.gov (United States)

    García, Beatriz; Merayo-Lloves, Jesús; Martin, Carla; Alcalde, Ignacio; Quirós, Luis M.; Vazquez, Fernando

    2016-01-01

    Infectious diseases remain an important global health problem. The interaction of a wide range of pathogen bacteria with host cells from many different tissues is frequently mediated by proteoglycans. These compounds are ubiquitous complex molecules which are not only involved in adherence and colonization, but can also participate in other steps of pathogenesis. To overcome the problem of microbial resistance to antibiotics new therapeutic agents could be developed based on the characteristics of the interaction of pathogens with proteoglycans. PMID:26941735

  2. The Role of Viral and Bacterial Pathogens in Gastrointestinal Cancer

    OpenAIRE

    Selgrad, Michael; Malfertheiner, Peter; Fini, Lucia; Goel, Ajay; Boland, C Richard; Ricciardiello, Luigi

    2008-01-01

    The association of Helicobacter pylori (H. pylori) with gastric cancer is thus far the best understood model to comprehend the causal relationship between a microbial pathogen and cancer in the human gastrointestinal tract. Besides H. pylori, a variety of other pathogens are now being recognized as potential carcinogens in different settings of human cancer. In this context, viral causes of human cancers are central to the issue since these account for 10–20% of cancers worldwide. In the case...

  3. Bacterial effect of accelerated electrons on several pathogens

    International Nuclear Information System (INIS)

    colibacterillesis and salmonellosis of calves' were developed in RIVU. By widening the application field of developed radiation biotechnology the 'Polyvalent vaccine against pasteurellesis, salmonellosis and colibacterillesis of farm animals' was created in recent years. The mentioned radio vaccines were successfully tested in laboratory and working environment and are widely used in veterinary practice in the farms of the Republic of Uzbekistan [3].For further broadening of the possibility to use the radiation biotechnology and to enrich the native arsenal of veterinary bio medication, it is presently planned to conduct large-scale research on the use of accelerated electrons (AE) to obtain in perspective new preventive materials. Several results of the beginning stage of this research are given in the present report.The suspensions of pathogenic strains of pasteurellesis, salmonellosis and Escherichia Coli strains were exposed to irradiation by accelerated electrons of microtron MT-22C. Taking into account the slightly higher resistance of bacteria against irradiation by accelerated electrons as compared to gamma-irradiation, the doses from 400 to 1100 kRad were used. At this, the special attention was paid to control the distribution of linear density of the current in scanning of AE beam, the distribution of linear density of the current in perpendicular scanning of AE beam and the value of absorbed dose. The studies showed that at AE irradiation by 400 kRad dose the bacterial survival rate is about 10 %, at 500 kRad-2-3 %, 600 kRad- less than 1 %. At the dose of 800 kRad only isolated colonies of bacteria survived. At AE irradiation by 900 kRad- 1.1 MRad dose, there was no increase the growth of bacteria's number. Since these data were obtained at the multiple repetition of results, it can be supposed that the minimal absolute devitalizing AE irradiation dose of bacteria lies in the region 0.9-1.0 MRad. At this, some inter-species and even intra species peculiarities in the

  4. Tomato pathogen genome may offer clues about bacterial evolution at the dawn of agriculture

    OpenAIRE

    Sutphin, Michael D.

    2008-01-01

    The availability of new genome sequencing technology has prompted a Virginia Tech plant scientist Boris Vinatzer to test an intriguing hypothesis about how agriculture's early beginnings may have impacted the evolution of plant pathogens.

  5. From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen

    KAUST Repository

    Weynberg, Karen D.

    2015-12-08

    Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to examine whether virulence is similarly driven by horizontally acquired elements. We demonstrate that bacteriophage genomes encoding toxin genes with homology to those found in pathogenic V. cholerae are integrated in V. coralliilyticus genomes. Virulence factors located on chromosomal pathogenicity islands also exist in some strains of V. coralliilyticus. The presence of these genetic signatures indicates virulence in V. coralliilyticus is driven by prophages and other horizontally acquired elements. Screening for pathogens of coral disease should target conserved regions in these elements.

  6. The olive knot disease as a model to study the role of interspecies bacterial communities in plant disease.

    Science.gov (United States)

    Buonaurio, Roberto; Moretti, Chiaraluce; da Silva, Daniel Passos; Cortese, Chiara; Ramos, Cayo; Venturi, Vittorio

    2015-01-01

    There is an increasing interest in studying interspecies bacterial interactions in diseases of animals and plants as it is believed that the great majority of bacteria found in nature live in complex communities. Plant pathologists have thus far mainly focused on studies involving single species or on their interactions with antagonistic competitors. A bacterial disease used as model to study multispecies interactions is the olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi (Psv). Knots caused by Psv in branches and other aerial parts of the olive trees are an ideal niche not only for the pathogen but also for many other plant-associated bacterial species, mainly belonging to the genera Pantoea, Pectobacterium, Erwinia, and Curtobacterium. The non-pathogenic bacterial species Erwinia toletana, Pantoea agglomerans, and Erwinia oleae, which are frequently isolated inside the olive knots, cooperate with Psv in modulating the disease severity. Co-inoculations of these species with Psv result in bigger knots and better bacterial colonization when compared to single inoculations. Moreover, harmless bacteria co-localize with the pathogen inside the knots, indicating the formation of stable bacterial consortia that may facilitate the exchange of quorum sensing signals and metabolites. Here we discuss the possible role of bacterial communities in the establishment and development of olive knot disease, which we believe could be taking place in many other bacterial plant diseases. PMID:26113855

  7. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    Science.gov (United States)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  8. Terminal reassortment drives the quantum evolution of type III effectors in bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    John Stavrinides

    2006-10-01

    Full Text Available Many bacterial pathogens employ a type III secretion system to deliver type III secreted effectors (T3SEs into host cells, where they interact directly with host substrates to modulate defense pathways and promote disease. This interaction creates intense selective pressures on these secreted effectors, necessitating rapid evolution to overcome host surveillance systems and defenses. Using computational and evolutionary approaches, we have identified numerous mosaic and truncated T3SEs among animal and plant pathogens. We propose that these secreted virulence genes have evolved through a shuffling process we have called "terminal reassortment." In terminal reassortment, existing T3SE termini are mobilized within the genome, creating random genetic fusions that result in chimeric genes. Up to 32% of T3SE families in species with relatively large and well-characterized T3SE repertoires show evidence of terminal reassortment, as compared to only 7% of non-T3SE families. Terminal reassortment may permit the near instantaneous evolution of new T3SEs and appears responsible for major modifications to effector activity and function. Because this process plays a more significant role in the evolution of T3SEs than non-effectors, it provides insight into the evolutionary origins of T3SEs and may also help explain the rapid emergence of new infectious agents.

  9. Development and application of the active surveillance of pathogens microarray to monitor bacterial gene flux

    Directory of Open Access Journals (Sweden)

    Hinds Jason

    2008-10-01

    Full Text Available Abstract Background Human and animal health is constantly under threat by emerging pathogens that have recently acquired genetic determinants that enhance their survival, transmissibility and virulence. We describe the construction and development of an Active Surveillance of Pathogens (ASP oligonucleotide microarray, designed to 'actively survey' the genome of a given bacterial pathogen for virulence-associated genes. Results The microarray consists of 4958 reporters from 151 bacterial species and include genes for the identification of individual bacterial species as well as mobile genetic elements (transposons, plasmid and phage, virulence genes and antibiotic resistance genes. The ASP microarray was validated with nineteen bacterial pathogens species, including Francisella tularensis, Clostridium difficile, Staphylococcus aureus, Enterococcus faecium and Stenotrophomonas maltophilia. The ASP microarray identified these bacteria, and provided information on potential antibiotic resistance (eg sufamethoxazole resistance and sulfonamide resistance and virulence determinants including genes likely to be acquired by horizontal gene transfer (e.g. an alpha-haemolysin. Conclusion The ASP microarray has potential in the clinic as a diagnostic tool, as a research tool for both known and emerging pathogens, and as an early warning system for pathogenic bacteria that have been recently modified either naturally or deliberately.

  10. Responses to Elevated c-di-GMP Levels in Mutualistic and Pathogenic Plant-Interacting Bacteria

    OpenAIRE

    Pérez-Mendoza, Daniel; Aragón, Isabel M.; Prada-Ramírez, Harold A.; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

    2014-01-01

    Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteri...

  11. Rapid in vivo analysis of synthetic promoters for plant pathogen phytosensing

    Directory of Open Access Journals (Sweden)

    Liu Wusheng

    2011-11-01

    Full Text Available Abstract Background We aimed to engineer transgenic plants for the purpose of early detection of plant pathogen infection, which was accomplished by employing synthetic pathogen inducible promoters fused to reporter genes for altered phenotypes in response to the pathogen infection. Toward this end, a number of synthetic promoters consisting of inducible regulatory elements fused to a red fluorescent protein (RFP reporter were constructed for use in phytosensing. Results For rapid analysis, an Agrobacterium-mediated transient expression assay was evaluated, then utilized to assess the inducibility of each synthetic promoter construct in vivo. Tobacco (Nicotiana tabacum cv. Xanthi leaves were infiltrated with Agrobacterium harboring the individual synthetic promoter-reporter constructs. The infiltrated tobacco leaves were re-infiltrated with biotic (bacterial pathogens or abiotic (plant defense signal molecules salicylic acid, ethylene and methyl jasmonate agents 24 and 48 hours after initial agroinfiltration, followed by RFP measurements at relevant time points after treatment. These analyses indicated that the synthetic promoter constructs were capable of conferring the inducibility of the RFP reporter in response to appropriate phytohormones and bacterial pathogens, accordingly. Conclusions These observations demonstrate that the Agrobacterium-mediated transient expression is an efficient method for in vivo assays of promoter constructs in less than one week. Our results provide the opportunity to gain further insights into the versatility of the expression system as a potential tool for high-throughput in planta expression screening prior to generating stably transgenic plants for pathogen phytosensing. This system could also be utilized for temporary phytosensing; e.g., not requiring stably transgenic plants.

  12. Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum.

    Directory of Open Access Journals (Sweden)

    Tuan Minh Tran

    2016-06-01

    Full Text Available Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner. These traps rapidly immobilized the pathogen and killed some cells, but most of the entangled bacteria eventually escaped. The R. solanacearum genome encodes two putative extracellular DNases (exDNases that are expressed during pathogenesis, suggesting that these exDNases contribute to bacterial virulence by enabling the bacterium to degrade and escape root border cell traps. We tested this hypothesis with R. solanacearum deletion mutants lacking one or both of these nucleases, named NucA and NucB. Functional studies with purified proteins revealed that NucA and NucB are non-specific endonucleases and that NucA is membrane-associated and cation-dependent. Single ΔnucA and ΔnucB mutants and the ΔnucA/B double mutant all had reduced virulence on wilt-susceptible tomato plants in a naturalistic soil-soak inoculation assay. The ΔnucA/B mutant was out-competed by the wild-type strain in planta and was less able to stunt root growth or colonize plant stems. Further, the double nuclease mutant could not escape from root border cells in vitro and was defective in attachment to pea roots. Taken together, these results demonstrate that extracellular DNases are novel virulence factors that help R. solanacearum successfully overcome plant defenses to infect plant roots and cause bacterial wilt disease.

  13. Escaping Underground Nets: Extracellular DNases Degrade Plant Extracellular Traps and Contribute to Virulence of the Plant Pathogenic Bacterium Ralstonia solanacearum.

    Science.gov (United States)

    Tran, Tuan Minh; MacIntyre, April; Hawes, Martha; Allen, Caitilyn

    2016-06-01

    Plant root border cells have been recently recognized as an important physical defense against soil-borne pathogens. Root border cells produce an extracellular matrix of protein, polysaccharide and DNA that functions like animal neutrophil extracellular traps to immobilize pathogens. Exposing pea root border cells to the root-infecting bacterial wilt pathogen Ralstonia solanacearum triggered release of DNA-containing extracellular traps in a flagellin-dependent manner. These traps rapidly immobilized the pathogen and killed some cells, but most of the entangled bacteria eventually escaped. The R. solanacearum genome encodes two putative extracellular DNases (exDNases) that are expressed during pathogenesis, suggesting that these exDNases contribute to bacterial virulence by enabling the bacterium to degrade and escape root border cell traps. We tested this hypothesis with R. solanacearum deletion mutants lacking one or both of these nucleases, named NucA and NucB. Functional studies with purified proteins revealed that NucA and NucB are non-specific endonucleases and that NucA is membrane-associated and cation-dependent. Single ΔnucA and ΔnucB mutants and the ΔnucA/B double mutant all had reduced virulence on wilt-susceptible tomato plants in a naturalistic soil-soak inoculation assay. The ΔnucA/B mutant was out-competed by the wild-type strain in planta and was less able to stunt root growth or colonize plant stems. Further, the double nuclease mutant could not escape from root border cells in vitro and was defective in attachment to pea roots. Taken together, these results demonstrate that extracellular DNases are novel virulence factors that help R. solanacearum successfully overcome plant defenses to infect plant roots and cause bacterial wilt disease. PMID:27336156

  14. Hard ticks and their bacterial endosymbionts (or would be pathogens)

    Czech Academy of Sciences Publication Activity Database

    Ahantarig, A.; Trinachartvanit, W.; Baimai, V.; Grubhoffer, Libor

    2013-01-01

    Roč. 58, č. 5 (2013), s. 419-428. ISSN 0015-5632 Institutional support: RVO:60077344 Keywords : Ixodes ricinus * Candidatus Midichloria mitochondrii * Francisella-like endosymbionts * vector Ambylomma americanum * fever group Rickettsiae * Dermacentor andersoni * spotted fever * borne pathogens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.145, year: 2013

  15. Epigenetics of the plant pathogen Zymoseptoria tritici

    OpenAIRE

    Schotanus, Klaas

    2015-01-01

    The genome of the fungal wheat pathogen Zymoseptoria tritici consists of thirteen essential chromosomes and several so-called dispensable chromosomes. These dispensable chromosomes encode only 6% of the protein coding genes of Z. tritici. To date no genes involved in pathogenicity are described on the dispensable chromosomes which can be lost after meiosis or mitotic cell division without any apparent effect on fitness. To investi...

  16. UV light inactivation of human and plant pathogens in unfiltered surface irrigation water.

    Science.gov (United States)

    Jones, Lisa A; Worobo, Randy W; Smart, Christine D

    2014-02-01

    Fruit and vegetable growers continually battle plant diseases and food safety concerns. Surface water is commonly used in the production of fruits and vegetables and can harbor both human- and plant-pathogenic microorganisms that can contaminate crops when used for irrigation or other agricultural purposes. Treatment methods for surface water are currently limited, and there is a need for suitable treatment options. A liquid-processing unit that uses UV light for the decontamination of turbid juices was analyzed for its efficacy in the treatment of surface waters contaminated with bacterial or oomycete pathogens, i.e., Escherichia coli, Salmonella enterica, Listeria monocytogenes, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, and Phytophthora capsici. Five-strain cocktails of each pathogen, containing approximately 10(8) or 10(9) CFU/liter for bacteria or 10(4) or 10(5) zoospores/liter for Ph. capsici, were inoculated into aliquots of two turbid surface water irrigation sources and processed with the UV unit. Pathogens were enumerated before and after treatment. In general, as the turbidity of the water source increased, the effectiveness of the UV treatment decreased, but in all cases, 99.9% or higher inactivation was achieved. Log reductions ranged from 10.0 to 6.1 and from 5.0 to 4.2 for bacterial pathogens and Ph. capsici, respectively. PMID:24242253

  17. Pathogenicity of and plant immunity to soft rot pectobacteria

    OpenAIRE

    Davidsson, Pär R.; Kariola, Tarja; Niemi, Outi; Palva, E. T.

    2013-01-01

    Soft rot pectobacteria are broad host range enterobacterial pathogens that cause disease on a variety of plant species including the major crop potato. Pectobacteria are aggressive necrotrophs that harbor a large arsenal of plant cell wall-degrading enzymes as their primary virulence determinants. These enzymes together with additional virulence factors are employed to macerate the host tissue and promote host cell death to provide nutrients for the pathogens. In contrast to (hemi)biotrophs s...

  18. The Top 10 oomycete pathogens in molecular plant pathology

    OpenAIRE

    Kamoun, Sophien; Furzer, Oliver; Jones, Jonathan D. G.; Judelson, Howard S; Ali, Gul Shad; Dalio, Ronaldo J. D.; Roy, Sanjoy Guha; Schena, Leonardo; Zambounis, Antonios; Panabières, Franck; Cahill, David; Ruocco, Michelina; Figueiredo, Andreia; Chen, Xiao-Ren; Hulvey, Jon

    2015-01-01

    Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant-pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidi...

  19. Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains

    Institute of Scientific and Technical Information of China (English)

    Rabia Naz; Asghari Bano

    2012-01-01

    Objective: To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods:Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results:Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions: The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

  20. Inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    Gita Eslami

    2014-06-01

    Full Text Available Background: Considering the high prevalence of bacterial vaginosis and its association with urinary tract infection in women and treatment of gynecologic problems occur when a high recurrence of bacterial vaginosis is often treated with antibiotics. The purpose of this study is to investigate the inhibitory effect of Lactobacillus rhamnosus on pathogenic bacteria isolated from women with bacterial vaginosis, respectively.Materials and Methods: 96 samples from women with bacterial vaginosis discharge referred to health centers dependent Shahid Beheshti University in 91-92 were taken by a gynecologist with a dacron swab and put in sterile tubes containing TSB broth and Thioglycollate broth and were immediately sent to the lab location in cold chain for the next stages of investigation. From Thioglycollate and TSB medium was cultured on blood agar and EMB and Palkam and Differential diagnosis environments, and then incubated for 24 h at 37°C. Strains of Lactobacillus rhamnosus were cultured in MRSA environment and were transfered to the lab. After purification of pathogenic bacteria, MIC methods and antibiogram, Lactobacillus rhamnosus inhibitory effect on pathogenic bacteria is checked. Statistical analysis was done by SPSS software v.16.Results: The results of this study show the inhibitory effect of Lactobacillus rhamnosus on some pathogenic bacteria that cause bacterial vaginosis, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae, Entrococcus, Listeria monocytogenes and E.Coli. Microscopic examination of stained smears of the large number of Lactobacillus and pathogenic bacteria showed reduced. The prevalence of abnormal vaginal discharge, history of drug use means of preventing pregnancy and douching, respectively, 61%, 55%, 42% and 13% respectively. Significant difference was observed between the use and non-use of IUD in women with bacterial vaginosis infection

  1. TLR4-dependent hepcidin expression by myeloid cells in response to bacterial pathogens

    OpenAIRE

    Peyssonnaux, Carole; Zinkernagel, Annelies S.; Datta, Vivekanand; Lauth, Xavier; Johnson, Randall S; Nizet, Victor

    2006-01-01

    Hepcidin is an antimicrobial peptide secreted by the liver during inflammation that plays a central role in mammalian iron homeostasis. Here we demonstrate the endogenous expression of hepcidin by macrophages and neutrophils in vitro and in vivo. These myeloid cell types produced hepcidin in response to bacterial pathogens in a toll-like receptor 4 (TLR4)-dependent fashion. Conversely, bacterial stimulation of macrophages triggered a TLR4-dependent reduction in the iron exporter ferroportin. ...

  2. Pulmonary bacterial pathogens in cystic fibrosis patients and antibiotic therapy: a tool for the health workers

    OpenAIRE

    2008-01-01

    Cystic fibrosis is the most common and best known genetic disease involving a defect in transepithelial Cl- transport by mutations in the CF gene on chromosome 7, which codes for the cystic fibrosis transmembrane conductance regulator protein (CFTR). The most serious symptoms are observed in the lungs, augmenting the risk of bacterial infection. The objective of this review was to describe the bacterial pathogens colonizing patients with cystic fibrosis. A systematic search was conducted usin...

  3. Evaluation of PCR Based Assays for the Improvement of Proportion Estimation of Bacterial and Viral Pathogens in Diarrheal Surveillance.

    Science.gov (United States)

    Guan, Hongxia; Zhang, Jingyun; Xiao, Yong; Sha, Dan; Ling, Xia; Kan, Biao

    2016-01-01

    Diarrhea can be caused by a variety of bacterial, viral and parasitic organisms. Laboratory diagnosis is essential in the pathogen-specific burden assessment. In the pathogen spectrum monitoring in the diarrheal surveillance, culture methods are commonly used for the bacterial pathogens' detection whereas nucleic acid based amplification, the non-cultural methods are used for the viral pathogens. Different methodology may cause the inaccurate pathogen spectrum for the bacterial pathogens because of their different culture abilities with the different media, and for the comparison of bacterial vs. viral pathogens. The application of nucleic acid-based methods in the detection of viral and bacterial pathogens will likely increase the number of confirmed positive diagnoses, and will be comparable since all pathogens will be detected based on the same nucleic acid extracts from the same sample. In this study, bacterial pathogens, including diarrheagenic Escherichia coli (DEC), Salmonella spp., Shigella spp., Vibrio parahaemolyticus and V. cholerae, were detected in 334 diarrheal samples by PCR-based methods using nucleic acid extracted from stool samples and associated enrichment cultures. A protocol was established to facilitate the consistent identification of bacterial pathogens in diarrheal patients. Five common enteric viruses were also detected by RT-PCR, including rotavirus, sapovirus, norovirus (I and II), human astrovirus, and enteric adenovirus. Higher positive rates were found for the bacterial pathogens, showing the lower proportion estimation if only using culture methods. This application will improve the quality of bacterial diarrheagenic pathogen survey, providing more accurate information pertaining to the pathogen spectrum associated with finding of food safety problems and disease burden evaluation. PMID:27065958

  4. Bovine respiratory disease complex (BRDC): Viral and bacterial pathogens in Serbia

    OpenAIRE

    Kurćubić V.; Đoković R.; Vidanović D.; Šekler M.; Matović K.; Ilić Z.; Stojković J.

    2013-01-01

    Pathogens causing BRDC in Serbia were investigated. Two herds of beef cattle with bovine respiratory disease were included, with twenty diseased calves (10 from each farm) were chosen for isolation of bacteria on artificial culture media and determination by aerobic cultivation. The most common bacterial pathogen was isolated was Pasteurella multocida. Diffusion method of sensitivity to antibiotics (antibiogram), revealed that Enrofloxacin and Floron were m...

  5. Sodium Ion Cycle in Bacterial Pathogens: Evidence from Cross-Genome Comparisons

    OpenAIRE

    Häse, Claudia C.; Fedorova, Natalie D.; Galperin, Michael Y.; Dibrov, Pavel A.

    2001-01-01

    Analysis of the bacterial genome sequences shows that many human and animal pathogens encode primary membrane Na+ pumps, Na+-transporting dicarboxylate decarboxylases or Na+-translocating NADH:ubiquinone oxidoreductase, and a number of Na+-dependent permeases. This indicates that these bacteria can utilize Na+ as a coupling ion instead of or in addition to the H+ cycle. This capability to use a Na+ cycle might be an important virulence factor for such pathogens as Vibrio cholerae, Neisseria m...

  6. Omics Approaches for the Engineering of Pathogen Resistant Plants.

    Science.gov (United States)

    Gomez-Casati, Diego F; Pagani, María A; Busi, María V; Bhadauria, Vijai

    2016-01-01

    The attack of different pathogens, such as bacteria, fungi and viruses has a negative impact on crop production. In counter such attacks, plants have developed different strategies involving the modification of gene expression, activation of several metabolic pathways and post-translational modification of proteins, which culminate into the accumulation of primary and secondary metabolites implicated in plant defense responses. The recent advancement in omics techniques allows the increase coverage of plants transcriptomes, proteomes and metabolomes during pathogen attack, and the modulation of the response after the infection. Omics techniques also allow us to learn more about the biological cycle of the pathogens in addition to the identification of novel virulence factors in pathogens and their host targets. Both approaches become important to decipher the mechanism underlying pathogen attacks and to develop strategies for improving disease-resistant plants. In this review, we summarize some of the contribution of genomics, transcriptomics, proteomics, metabolomics and metallomics in devising the strategies to obtain plants with increased resistance to pathogens. These approaches constitute important research tools in the development of new technologies for the protection against diseases and increase plant production. PMID:26363625

  7. Molecular detection of plant pathogenic bacteria using polymerase chain reaction single-strand conformation polymorphism

    Institute of Scientific and Technical Information of China (English)

    Chandrashekar Srinivasa; Umesha Sharanaiah; Chandan Shivamallu

    2012-01-01

    The application of polymerase chain reaction (PCR) technology to molecular diagnostics holds great promise for the early identification of agriculturally important plant pathogens.Ralstonia solanacearum,Xanthomoans axonopodis pv.vesicatoria,and Xanthomonas oryzae pv.oryzae are phytopathogenic bacteria,which can infect vegetables,cause severe yield loss.PCR-single-strand conformation polymorphism (PCR-SSCP) is a simple and powerful technique for identifying sequence changes in amplified DNA.The technique of PCR-SSCP is being exploited so far,only to detect and diagnose human bacterial pathogens in addition to plant pathogenic fungi.Selective media and serology are the commonly used methods for the detection of plant pathogens in infected plant materials.In this study,we developed PCR-SSCP technique to identify phytopathogenic bacteria.The PCR product was denatured and separated on a non-denaturing polyacrylamide gel.SSCP banding patterns were detected by silver staining of nucleic acids.We tested over 56 isolates of R. solanacearum,44 isolates of X. axonopodis pv.vesicatoria,and 20 isolates of X.oryzae pv.oryzae.With the use of universal primer 16S rRNA,we could discriminate such species at the genus and species levels.Speciesspecific patterns were obtained for bacteria R.solanacearum,X.axonopodis pv.vesicatoria,and X.oryzae pv.oryzae.The potential use of PCR-SSCP technique for the detection and diagnosis of phytobacterial pathogens is discussed in the present paper.

  8. Detection of a pathogen shift among the pectolytic bacterial pathogens of potato in Washington State

    Science.gov (United States)

    Bacterial tuber soft rot, aerial stem rot and blackleg are significant diseases of potatoes in Washington State. These diseases are caused by Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, and Dickeya chrysanthemi, all characterized by the ability to produce pectolytic ...

  9. Evaluation of PCR based assays for the improvement of proportion estimation of bacterial and viral pathogens in diarrheal surveillance

    Directory of Open Access Journals (Sweden)

    Hongxia eGuan

    2016-03-01

    Full Text Available AbstractDiarrhea can be caused by a variety of bacterial, viral and parasitic organisms. Laboratory diagnosis is essential in the pathogen-specific burden assessment. In the pathogen spectrum monitoring in the diarrheal surveillance, culture methods are commonly used for the bacterial pathogens’ detection whereas nucleic acid based amplification, the non-cultural methods are used for the viral pathogens. Different methodology may cause the inaccurate pathogen spectrum for the bacterial pathogens because of their different culture abilities with the different media, and for the comparison of bacterial vs. viral pathogens. The application of nucleic acid-based methods in the detection of viral and bacterial pathogens will likely increase the number of confirmed positive diagnoses, and will be comparable since all pathogens will be detected based on the same nucleic acid extracts from the same sample. In this study, bacterial pathogens, including diarrheagenic Escherichia coli (DEC, Salmonella spp., Shigella spp., Vibrio parahaemolyticus and V. cholerae, were detected in 334 diarrheal samples by PCR-based methods using nucleic acid extracted from stool samples and associated enrichment cultures. A protocol was established to facilitate the consistent identification of bacterial pathogens in diarrheal patients. Five common enteric viruses were also detected by RT-PCR, including rotavirus, sapovirus, norovirus (I and II, human astrovirus, and enteric adenovirus. Higher positive rates were found for the bacterial pathogens, showing the lower proportion estimation if only using culture methods. This application will improve the quality of bacterial diarrheagenic pathogen survey, providing more accurate information pertaining to the pathogen spectrum associated with finding of food safety problems and disease burden evaluation.

  10. Reactive oxygen species, essential molecules, during plant-pathogen interactions.

    Science.gov (United States)

    Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

    2016-06-01

    Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule. PMID:26950921

  11. Emerging Plant Pathogenic Bacteria and Global Warming

    Science.gov (United States)

    Several bacteria, previously classified as non-fluorescent, oxidase positive pseudomonads, Ralstonia, Acidovorax, and Burkholdria have emerged as serious problems world-wide. Perhaps the most destructive is R. solanacearum (RS), a soilborne pathogen with a very wide host range. RS race 3, biovar 2...

  12. Pathogenic Triad in Bacterial Meningitis: Pathogen Invasion, NF-κB Activation, and Leukocyte Transmigration that Occur at the Blood-Brain Barrier

    OpenAIRE

    Wang, Shifu; Peng, Liang; Gai, Zhongtao; Zhang, Lehai; Jong, Ambrose; Cao, Hong; Huang, Sheng-He

    2016-01-01

    Bacterial meningitis remains the leading cause of disabilities worldwide. This life-threatening disease has a high mortality rate despite the availability of antibiotics and improved critical care. The interactions between bacterial surface components and host defense systems that initiate bacterial meningitis have been studied in molecular and cellular detail over the past several decades. Bacterial meningitis commonly exhibits triad hallmark features (THFs): pathogen penetration, nuclear fa...

  13. BACTERIAL MICROORGANISMS ASSOCIATED WITH THE PLANT TISSUE CULTURE: IDENTIFICATION AND POSSIBLE ROLE (review)

    OpenAIRE

    S.E. DUNAEVA; Yu, S.

    2015-01-01

    Effective sterilization of plant explants and antiseptics rules compliance do not exclude the presence of so-called covert (endophytic) bacteria in in vitro cultures. But the role of these bacteria in tissues cultures has been not enough studied whereas it was related to the explants regeneration capacity and the possibility of animal and human cells transformation under in vitro cultivation. Bacterial strains pathogenic to humans can be stably maintained in cultivated tissues and ex vitro pl...

  14. Impact of CRISPR immunity on the emergence and virulence of bacterial pathogens

    OpenAIRE

    Hatoum-Aslan, Asma; Marraffini, Luciano A.

    2013-01-01

    CRISPR-Cas systems protect prokaryotes from viruses and plasmids and function primarily as an adaptive immune system in these organisms. Recent discoveries, however, revealed unexpected roles for CRISPR loci as barriers to horizontal gene transfer and as modulators of gene expression. We review how both of these functions of CRISPR-Cas systems can affect the emergence and virulence of human bacterial pathogens.

  15. Analysis of apple (Malus) responses to bacterial pathogens using an oligo microarray

    Science.gov (United States)

    Fire blight is a devastating disease of apple (Malus x domestica) caused by the bacterial pathogen Erwinia amylovora (Ea). When infiltrated into host leaves, Ea induces reactions similar to a hypersensitive response (HR). Type III (T3SS) associated effectors, especially DspA/E, are suspected to ha...

  16. Draft Genome Sequence of 16SrIII-J Phytoplasma, a Plant Pathogenic Bacterium with a Broad Spectrum of Hosts

    Science.gov (United States)

    Zamorano, Alan

    2016-01-01

    Phytoplasmas are bacterial plant pathogens that can affect different vegetal hosts. In South America, a phytoplasma belonging to ribosomal subgroup 16SrIII-J has been reported in many crops. Here we report its genomic draft sequence, showing a total length of 687,253 bp and a G+C content of 27.72%. PMID:27365349

  17. Pathogenicity in Verticillium on strawberry plants

    OpenAIRE

    Schubert, P.; J. Golldack; Schwärzel, H.; Lentzsch, P.

    2008-01-01

    In the most common strawberry cv. ’Elsanta’, Verticillium infection can lead to rapid wilt and even death of plants. It is known, that a dead plant can be located directly beside vital ones. In a survey of 8 fields in Brandenburg, Mecklenburg- Vorpommern, Sachsen-Anhalt and Sachsen, 432 genotypes of Verticillium dahliae Kleb. were isolated from wilted and even vital plants from 8 fields and classified by PCR-fingerprints. For strawberries, the genotypes can be classified as apa...

  18. Homoserine lactones: Do plants really listen to bacterial talk?

    OpenAIRE

    Klein, Ilona; von Rad, Uta; Durner, Jörg

    2009-01-01

    The bacterial quorum sensing signals N-acyl-L-homoserine lactones (AHL) enable bacterial cells to regulate gene expression depending on population density, which eventually leads to invasion of hosts. Only little is known about the molecular ways of plants reacting to these bacterial signals. Recently, we showed that the contact of Arabidopsis thaliana roots with N-hexanoyl-DL-homoserine-lactone (HHL) resulted in distinct transcriptional changes in roots and shoots, respectively. In addition,...

  19. Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.

    Directory of Open Access Journals (Sweden)

    Lijuan Zhou

    Full Text Available Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB, a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and

  20. Toxicity of (+)- and (-)-gossypol to the plant pathogen, Rhizoctonia solani.

    Science.gov (United States)

    Puckhaber, Lorraine S; Dowd, Michael K; Stipanovic, Robert D; Howell, Charles R

    2002-11-20

    The dimeric sesquiterpene gossypol occurs naturally in cottonseed and other parts of the cotton plant. Gossypol exists as enantiomers because of the restricted rotation around the central binaphthyl bond. The (-)-enantiomer is toxic to nonruminant animals while the (+)-enantiomer exhibits little, if any, toxicity to these animals. Developing cotton plants with low levels of the (-)-gossypol could expand the use of cottonseed as a feed source. Gossypol also may play a role in protecting the plant from pathogens. The relative toxicity of (+)- and (-)-gossypol to plant pathogens has not been reported. We measured the concentration of (+)- and (-)-gossypol in roots from cotton seedlings that were treated with the biocontrol agent Trichoderma virens that induces biosynthesis of gossypol and related terpenoids in cotton roots. (-)-Gossypol was the minor enantiomer in control and treated roots, but levels were slightly higher in roots from T. virens-treated seed. We also determined the toxicity of the gossypol enantiomers and the racemate to the seedling disease pathogen Rhizoctonia solani. The (+)- and (-)-enantiomers of gossypol and the racemate are equally effective in inhibiting growth of this pathogen. The lethal doses of the gossypols required to kill the pathogen appeared to be similar, but their toxicities are significantly less than those of related cotton and kenaf sesquiterpenes. The results indicate that altering the enantiomeric ratio in cotton roots will not adversely affect the resistance of seedlings to the seedling pathogen R. solani. PMID:12428953

  1. 'Nothing is permanent but change'- antigenic variation in persistent bacterial pathogens.

    Science.gov (United States)

    Palmer, Guy H; Bankhead, Troy; Lukehart, Sheila A

    2009-12-01

    Pathogens persist in immunocompetent mammalian hosts using various strategies, including evasion of immune effectors by antigenic variation. Among highly antigenically variant bacteria, gene conversion is used to generate novel expressed variants from otherwise silent donor sequences. Recombination using oligonucleotide segments from multiple donors is a combinatorial mechanism that tremendously expands the variant repertoire, allowing thousands of variants to be generated from a relatively small donor pool. Three bacterial pathogens, each encoded by a small genome (Treponema pallidum TprK and Anaplasma marginale Msp2 expression sites and donors are chromosomally encoded. Both T. pallidum and A. marginale generate antigenic variants in vivo in individual hosts and studies at the population level reveal marked strain diversity in the variant repertoire that may underlie pathogen strain structure and the capacity for re-infection and heterologous strain superinfection. Here, we review gene conversion in bacterial antigenic variation and discuss the short- and long-term selective pressures that shape the variant repertoire. PMID:19709057

  2. Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast, Tamilnadu, India

    Institute of Scientific and Technical Information of China (English)

    Suyambu Rajan; Parameshwaran Suvetha; Thiyagarajan Thirunalasundari; Solomon Jeeva

    2015-01-01

    Objective: To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria, as most of the pathogens develop drug resistance against commonly used antibiotics. Methods: Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance. Extraction of bioactive principles was done with water and ethanol. Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains. Results: Of the 6 different plant materials tested, extracts prepared from Psidium guajava leaves showed significantly higher efficacy. Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts. Conclusions: The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity, and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment, management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district, Tamilnadu, India.

  3. Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast, Tamilnadu, India

    Directory of Open Access Journals (Sweden)

    Suyambu Rajan

    2015-08-01

    Full Text Available Objective: To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria, as most of the pathogens develop drug resistance against commonly used antibiotics. Methods: Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance. Extraction of bioactive principles was done with water and ethanol. Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains. Results: Of the 6 different plant materials tested, extracts prepared from Psidium guajava leaves showed significantly higher efficacy. Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts. Conclusions: The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity, and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment, management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district, Tamilnadu, India.

  4. Quantitative PCR monitoring of antibiotic resistance genes and bacterial pathogens in three European artificial groundwater recharge systems.

    Science.gov (United States)

    Böckelmann, Uta; Dörries, Hans-Henno; Ayuso-Gabella, M Neus; Salgot de Marçay, Miquel; Tandoi, Valter; Levantesi, Caterina; Masciopinto, Costantino; Van Houtte, Emmanuel; Szewzyk, Ulrich; Wintgens, Thomas; Grohmann, Elisabeth

    2009-01-01

    Aquifer recharge presents advantages for integrated water management in the anthropic cycle, namely, advanced treatment of reclaimed water and additional dilution of pollutants due to mixing with natural groundwater. Nevertheless, this practice represents a health and environmental hazard because of the presence of pathogenic microorganisms and chemical contaminants. To assess the quality of water extracted from recharged aquifers, the groundwater recharge systems in Torreele, Belgium, Sabadell, Spain, and Nardò, Italy, were investigated for fecal-contamination indicators, bacterial pathogens, and antibiotic resistance genes over the period of 1 year. Real-time quantitative PCR assays for Helicobacter pylori, Yersinia enterocolitica, and Mycobacterium avium subsp. paratuberculosis, human pathogens with long-time survival capacity in water, and for the resistance genes ermB, mecA, blaSHV-5, ampC, tetO, and vanA were adapted or developed for water samples differing in pollutant content. The resistance genes and pathogen concentrations were determined at five or six sampling points for each recharge system. In drinking and irrigation water, none of the pathogens were detected. tetO and ermB were found frequently in reclaimed water from Sabadell and Nardò. mecA was detected only once in reclaimed water from Sabadell. The three aquifer recharge systems demonstrated different capacities for removal of fecal contaminators and antibiotic resistance genes. Ultrafiltration and reverse osmosis in the Torreele plant proved to be very efficient barriers for the elimination of both contaminant types, whereas aquifer passage followed by UV treatment and chlorination at Sabadell and the fractured and permeable aquifer at Nardò posed only partial barriers for bacterial contaminants. PMID:19011075

  5. Evaluation of antimicrobial properties of four plant extracts against human pathogens

    Institute of Scientific and Technical Information of China (English)

    Anjali Rawani; Sudin Pal; GoutamChandra

    2011-01-01

    Objective: To investigate the antibacterial activity of the extracts of Alternanthera philoxeroides (A. philoxeroides), Plumeria obtusa (P. obtusa), Polyalthia cerasoides (P. cerasoides) and Ixoraacuminate (I. acuminate) against human pathogens. Methods: Aqueous and chloroform: methanol (1:1) extracts of the dried leaf of A. philoxeroides, flowers of P. obtusa, fruits of P. cerasoides and flowers of I. acuminate were tested in vitro by the disk diffusion method against four bacterial strains, namely, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonasaeruginosa. Susceptibility of four reference bacterial strains to some antibiotics in nutrient agar was also tested. Minimal inhibitory concentration (MIC) values were determined and qualitative phytochemical analysis of the crude extract of the tested plant parts was done. Results: Both the aqueous and the chloroform: methanol (1:1) extracts of P. cerasoides showed the strongest activity, followed by flowers of P. obtusa, leaves of A. philoxeroides and flowers of I. acuminate. Aqueous extracts of all the plant parts appeared to have less antibacterial activity than the chloroform:methanol (1:1) extracts. The result of phytochemical analysis of the crude extract of the tested plants showed that flavonoid was absent from all plant parts whereas steroid was present in all tested plant parts. Conclusions: The results support that these plant extracts can be used for the treatment of bacterial diseases.

  6. Intracellular phase for an extracellular bacterial pathogen: MgtC shows the way

    Directory of Open Access Journals (Sweden)

    Audrey Bernut

    2015-08-01

    Full Text Available Pseudomonas aeruginosa is an extracellular pathogen known to impair host phagocytic functions. However, our recent results identify MgtC as a novel actor in P. aeruginosa virulence, which plays a role in an intramacrophage phase of this pathogen. In agreement with its intracellular function, P. aeruginosa mgtC gene expression is strongly induced when the bacteria reside within macrophages. MgtC was previously known as a horizontally-acquired virulence factor important for multiplication inside macrophages in several intracellular bacterial pathogens. MgtC thus provides a singular example of a virulence determinant that subverts macrophages both in intracellular and extracellular pathogens. Moreover, we demonstrate that P. aeru-ginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosaMgtC prevents biofilm formation. We propose that MgtC has a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to the host in relation to the different bacterial lifestyles. MgtC thus appears as an attractive target for antivirulence strategies and our work provides a natural peptide as MgtC antagonist, which paves the way for the development of MgtC inhibitors.

  7. Seaweed Polysaccharides and Derived Oligosaccharides Stimulate Defense Responses and Protection Against Pathogens in Plants

    Directory of Open Access Journals (Sweden)

    Alejandra Moenne

    2011-11-01

    Full Text Available Plants interact with the environment by sensing “non-self” molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been shown that cell wall and storage polysaccharides from green, brown and red seaweeds (marine macroalgae corresponding to ulvans, alginates, fucans, laminarin and carrageenans can trigger defense responses in plants enhancing protection against pathogens. In addition, oligosaccharides obtained by depolymerization of seaweed polysaccharides also induce protection against viral, fungal and bacterial infections in plants. In particular, most seaweed polysaccharides and derived oligosaccharides trigger an initial oxidative burst at local level and the activation of salicylic (SA, jasmonic acid (JA and/or ethylene signaling pathways at systemic level. The activation of these signaling pathways leads to an increased expression of genes encoding: (i Pathogenesis-Related (PR proteins with antifungal and antibacterial activities; (ii defense enzymes such as pheylalanine ammonia lyase (PAL and lipoxygenase (LOX which determine accumulation of phenylpropanoid compounds (PPCs and oxylipins with antiviral, antifugal and antibacterial activities and iii enzymes involved in synthesis of terpenes, terpenoids and/or alkaloids having antimicrobial activities. Thus, seaweed polysaccharides and their derived oligosaccharides induced the accumulation of proteins and compounds with antimicrobial activities that determine, at least in part, the enhanced protection against pathogens in plants.

  8. Minimum Inhibitory Concentration Analysis of Nerium oleander against Bacterial Pathogens

    Institute of Scientific and Technical Information of China (English)

    M Abu Hena Mostofa Jamal; Shahedur Rahman; Md Azizul Islam; Md Rezaul Karim; Md Samsul Alam; Md Ziaur Rahman

    2012-01-01

    Objective: In this present study, it is tried to find out the antimicrobial effect and Minimum Inhibitory Concentration (MIC) of Nerium oleander against Bacillus subtilis (IFO 3026), Sarcina lutea (IFO 3232), Escherichia coli (IFO 3007) and Klebsiella Pneumoniae (ATTC 10031). Methods:Powered leaves were prepared and used for extraction with various solvents, viz, the petroleum ether, and chloroform extract of the oleander. All the solvent extracts were evaporated to dryness. Using the disc diffusion method, the bacterial growth were inhibited, Results: Among the solvent extracts tested, petroleum ether extract inhibited the growth of all the tested bacteria having various degrees of inhibition zones. Highest inhibitory activity was observed against E. coli (1.9 cm) and minimum inhibitory concentration was observed 2μg/ml also against E. coli. Both results were observed in case of petroleum ether extract. Petroleum ether extract also showed inhibitory zones of 1.8 cm, 1.4 cm and 1.5cm against B. subtilis, S. lutea and K. pneumoniae. On the other hand chloroform extract was observed to have inhibition zones of 1.2 cm, 1.6 cm, 1.8 cm and 1.5 cm against B. subtilis, S. lutea, E. coli and K. pneumoniae respectively. Conclusions: The study demonstrated that the petroleum ether extract of N. oleander is potentially good source of antibacterial agents. Further evaluation is necessary to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.

  9. Host-plant-mediated effects of Nadefensin on herbivore and pathogen resistance in Nicotiana attenuata

    Directory of Open Access Journals (Sweden)

    Baldwin Ian T

    2008-10-01

    Full Text Available Abstract Background The adage from Shakespeare, "troubles, not as single spies, but in battalions come," holds true for Nicotiana attenuata, which is commonly attacked by both pathogens (Pseudomonas spp. and herbivores (Manduca sexta in its native habitats. Defense responses targeted against the pathogens can directly or indirectly influence the responses against the herbivores. Nadefensin is an effective induced defense gene against the bacterial pathogen Pseudomonas syringae pv tomato (PST DC3000, which is also elicited by attack from M. sexta larvae, but whether this defense protein influences M. sexta's growth and whether M. sexta-induced Nadefensin directly or indirectly influences PST DC3000 resistance are unknown. Results M. sexta larvae consumed less on WT and on Nadefensin-silenced N. attenuata plants that had previously been infected with PST DC3000 than on uninfected plants. WT plants infected with PST DC3000 showed enhanced resistance to PST DC3000 and decreased leaf consumption by M. sexta larvae, but larval mass gain was unaffected. PST DC3000-infected Nadefensin-silenced plants were less resistant to subsequent PST DC3000 challenge, and on these plants, M. sexta larvae consumed less and gained less mass. WT and Nadefensin-silenced plants previously damaged by M. sexta larvae were better able to resist subsequent PST DC3000 challenges than were undamaged plants. Conclusion These results demonstrate that Na-defensin directly mediates defense against PST DC3000 and indirectly against M. sexta in N. attenuata. In plants that were previously infected with PST DC3000, the altered leaf chemistry in PST DC3000-resistant WT plants and PST DC3000-susceptible Nadefensin-silenced plants differentially reduced M. sexta's leaf consumption and mass gain. In plants that were previously damaged by M. sexta, the combined effect of the altered host plant chemistry and a broad spectrum of anti-herbivore induced metabolomic responses was more

  10. SCREENING OF FLUORESCENT RHIZOBACTERIA FOR THE BIOCONTROL OF SOILBORNE PLANT PATHOGENIC FUNGI

    Directory of Open Access Journals (Sweden)

    ANELISE DIAS

    2014-01-01

    Full Text Available The biocontrol of soilborne plant pathogens represents a promising approach from the environ- mental and practical points of view. Fluorescent pseudomonad rhizobacteria are well known by their antagonis- tic capacity towards several plant pathogens due to a diversity of antimicrobial metabolites they produce. This study was conceived to select and characterize rhizobacteria having antagonistic potential towards the patho- genic fungi Rhizoctonia solani and Sclerotium rolfsii. A total of 94 bacterial strains isolated from the rhizospheres of four vegetable species under organic cultivation were evaluated. Twenty-two strains which predominate in lettuce and rudbeckia rhizospheres showed identical biochemical profiles to Pseudomonas fluo- rescens, while in kale and parsley rhizospheres identical profiles to Pseudomonas putida (subgroups A and B strains prevailed. Two types of antagonism were verified in vitro and defined as competition and inhibition of mycelial growth. Sixty percent of the evaluated strains showed antagonistic potential and, among those, 24 strains expressed antagonism to both target fungi, with P. fluorescens being the most representative bacterial species. This work clearly identified a number of strains with potential for use as plant growth-promoting and biocontrol of the two soilborne fungal pathogens in vegetable crops production systems.

  11. Bacterial-induced cell reprogramming to stem cell-like cells: new premise in host-pathogen interactions

    OpenAIRE

    Hess, Samuel; Rambukkana, Anura

    2014-01-01

    Bacterial pathogens employ a myriad of strategies to alter host tissue cell functions for bacterial advantage during infection. Recent advances revealed a fusion of infection biology with stem cell biology by demonstrating developmental reprogramming of lineage committed host glial cells to progenitor/stem cell-like cells by an intracellular bacterial pathogen Mycobacterium leprae. Acquisition of migratory and immunomodulatory properties of such reprogrammed cells provides an added advantage ...

  12. Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae

    Directory of Open Access Journals (Sweden)

    Boknam Jung

    2013-12-01

    Full Text Available The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

  13. Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection.

    Science.gov (United States)

    Sistrunk, Jeticia R; Nickerson, Kourtney P; Chanin, Rachael B; Rasko, David A; Faherty, Christina S

    2016-10-01

    Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens. PMID:27464994

  14. Isolation of 12 Bacterial endophytes from some mangrove plants and determination of, antimicrobial properties of the isolates and the plant extracts

    OpenAIRE

    Ibrahim M.S Eldeen

    2014-01-01

    The mangrove designates a highly productive ecosystem with important economic and environmental functions. Endophytes are microorganisms that live in the intercellular spaces of plant tissue. This study aimed to isolate and identify bacterial endophytes from five mangrove plants and to determine, antimicrobial properties of the isolates and the plant extracts against four pathogenic bacteria: Bacillus cereus, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium using the deferr...

  15. Host response to respiratory bacterial pathogens as identified by integrated analysis of human gene expression data.

    Directory of Open Access Journals (Sweden)

    Steven B Smith

    Full Text Available Respiratory bacterial pathogens are one of the leading causes of infectious death in the world and a major health concern complicated by the rise of multi-antibiotic resistant strains. Therapeutics that modulate host genes essential for pathogen infectivity could potentially avoid multi-drug resistance and provide a wider scope of treatment options. Here, we perform an integrative analysis of published human gene expression data generated under challenges from the gram-negative and Gram-positive bacteria pathogens, Pseudomonas aeruginosa and Streptococcus pneumoniae, respectively. We applied a previously described differential gene and pathway enrichment analysis pipeline to publicly available host mRNA GEO datasets resulting from exposure to bacterial infection. We found 72 canonical human pathways common between four GEO datasets, representing P. aeruginosa and S. pneumoniae. Although the majority of these pathways are known to be involved with immune response, we found several interesting new interactions such as the SUMO1 pathway that might have a role in bacterial infections. Furthermore, 36 host-bacterial pathways were also shared with our previous results for respiratory virus host gene expression. Based on our pathway analysis we propose several drug-repurposing opportunities supported by the literature.

  16. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jose L Martinez

    2012-01-01

    Full Text Available It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actually found in human pathogens. Along the review, the role that different processes as founder effect, ecological connectivity, fitness costs or second-order selection may have on the establishment of a specific resistance determinant in the population of bacterial pathogens is analysed.

  17. In vitro anti- bacterial activity of leaves extracts of Albizia lebbeck Benth against some selected pathogens

    Institute of Scientific and Technical Information of China (English)

    Mohammed Nazneen Bobby; Edward Gnanaraj Wesely; MarimuthuAntonisamy Johnson

    2012-01-01

    Objective: To screen the anti-bacterial activity of Albizia lebbeck (A. lebbeck) Benth leaves extract against the selected bacterial pathogens viz., Bacillus subtilis (MTCC441), Escherichia coli (MTCC443), Klebsiella pneumonia (MTCC 109), Proteus vulgaris (MTCC742), Pseudomonas aeruginosa (MTCC741), Salmonella typhii (MTCC733) and Staphylococus aureus (MTCC96).Methods:The leaves extracts of A. lebbeck was tested against bacteria by the agar disc diffusion method. Results: Results of the present study indicated that different extracts of A. lebbeck showed inhibitory effects against the pathogens. The present study results demonstrated that methanolic extracts of A. lebbeck conferred the widest spectrum activities that inhibited the growth of all studied pathogens with the maximum zone of inhibition. The methanolic extracts ofA. lebbeck illustrated the highest zone of inhibition against the pathogens Bacillus subtilis (16 mm), Escherichia coli (22 mm), Klebsiella pneumonia (11 mm), Proteus vulgaris (18 mm), Pseudomonas aeruginosa (22 mm), Salmonella typhii (23 mm) and Staphylococus aureus (17 mm). The ethyl acetate extracts demonstrated maximum zone of inhibition against Escherichia coli (26 mm), Pseudomonas aeruginosa (22 mm) and Klebsiella pneumonia (16 mm). Conclusions: It is expected that this study would direct to the establishment of some active compounds that could be used to formulate new and more potent anti-bacterial drugs of natural origin.

  18. Efficacy of zinc as an antibacterial agent against enteric bacterial pathogens

    International Nuclear Information System (INIS)

    Background: Diarrhoea is a serious threat all over the world with great economic implications especially evident in the developing world. This study was aimed at determining in vitro efficacy of Zinc (Zn) against common enteric bacterial pathogens. Method: A total of 100 bacterial enteric pathogens: Salmonellae (n=16), enteropathogenic Escherichia coli (EPEC) (n=26), Shigellae (n=28) and Vibrio cholerae (n=30) were isolated from diarrhoeal stool specimens at Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi during April 2009 to Jan 2010. These isolates were tested against various concentrations of Zn supplemented in Mueller Hinton (MH) agar using a multipoint inoculator. A minimum inhibitory concentration of active Zn in ZnSO/sub 4/.7H/sub 2/O ranging from 0.03 mg/ml to 1 mg/ml was used. Results: Zn completely inhibited the growth of all the tested pathogens and most of them were inhibited at a concentration of 0.06 mg/ml to 0.5 mg/ml of Zn. Conclusions: Zinc has an excellent antibacterial activity against enteric bacterial pathogens common in our setup which may provide basis for treatment of diarrhoea. Clinical study based on these findings is recommended. (author)

  19. Radiation Sensitivity of some Food Borne Bacterial Pathogens in Animal Foods and Minced Meat

    International Nuclear Information System (INIS)

    Bacteriological examination of 100 samples of animal food stuffs (fish meal and bone and meat meal; as models of dry food materials) and 50 samples of minced meat (as a model of moist food materials) revealed the isolation of different bacterial pathogens; Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Proteus spp., Staph. aureus and Salmonella species, in a decreasing order of occurrence. In the experiment; the dry food stuffs were sterilized in autoclave and the minced meat was sterilized by gamma irradiation at 10 kGy. The efficacy of gamma irradiation against the inoculated bacterial isolates (E coli 0157: H7, Salmonella enteritidis and Staph. aureus) in animal food stuffs and minced meat was investigated. Irradiated samples were stored at room temperature (25 degree C) for 2 weeks. The food borne pathogens used in this study showed a difference in radiation sensitivity. E. coli 0157: H7, Staphylococcus aureus and Salmonella enteritidis were eradicated at 1, 2 and 3 kGy, respectively. Also, inoculated pathogens in minced meat were more sensitive to ionizing radiation than dry animal food stuffs. It could be concluded that low doses of gamma irradiation are effective means of inactivating pathogenic bacteria. This radiation sensitivity is related to the bacterial isolates and the evaluated growth

  20. Development of Quorum-Based Anti-Virulence Therapeutics Targeting Gram-Negative Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Wen Shan Yew

    2013-08-01

    Full Text Available Quorum sensing is a cell density-dependent signaling phenomenon used by bacteria for coordination of population-wide phenotypes, such as expression of virulence genes, antibiotic resistance and biofilm formation. Lately, disruption of bacterial communication has emerged as an anti-virulence strategy with enormous therapeutic potential given the increasing incidences of drug resistance in pathogenic bacteria. The quorum quenching therapeutic approach promises a lower risk of resistance development, since interference with virulence generally does not affect the growth and fitness of the bacteria and, hence, does not exert an associated selection pressure for drug-resistant strains. With better understanding of bacterial communication networks and mechanisms, many quorum quenching methods have been developed against various clinically significant bacterial pathogens. In particular, Gram-negative bacteria are an important group of pathogens, because, collectively, they are responsible for the majority of hospital-acquired infections. Here, we discuss the current understanding of existing quorum sensing mechanisms and present important inhibitory strategies that have been developed against this group of pathogenic bacteria.

  1. Pathogen infection drives patterns of nutrient resorption in citrus plants.

    Science.gov (United States)

    Cao, Jirong; Cheng, Chunzhen; Yang, Junjie; Wang, Qibing

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen 'Candidatus Liberibacter asiaticus' grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of 'Ca. L. asiaticus' infection on nitrogen (N) and phosphorus (P) concentrations and resorption in different citrus species (i.e. Citrus reticulata, Citrus limon and Citrus maxima). HLB-pathogen infection had distinctive impacts on nutrient resorption in different species. P resorption efficiency substantially decreased in infected C. reticulata plants relative to the healthy plants in summer, which may account for the marked decrease in the average fruit yield. P resorption was more efficient in infected C. limon plants than in the healthy plants. However, for C. maxima plants, HLB had no significant effects on N:P ratio in live leaves and resorption efficiency as well as on fruit yield. Keeping efficient internal nutrient cycling can be a strategy of citrus species being tolerant to HLB. PMID:26419510

  2. Titanium dioxide nanoparticles enhance mortality of fish exposed to bacterial pathogens

    International Nuclear Information System (INIS)

    Nano-TiO2 is immunotoxic to fish and reduces the bactericidal function of fish neutrophils. Here, fathead minnows (Pimephales promelas) were exposed to low and high environmentally relevant concentration of nano-TiO2 (2 ng g−1 and 10 μg g−1 body weight, respectively), and were challenged with common fish bacterial pathogens, Aeromonas hydrophila or Edwardsiella ictaluri. Pre-exposure to nano-TiO2 significantly increased fish mortality during bacterial challenge. Nano-TiO2 concentrated in the kidney and spleen. Phagocytosis assay demonstrated that nano-TiO2 has the ability to diminish neutrophil phagocytosis of A. hydrophila. Fish injected with TiO2 nanoparticles displayed significant histopathology when compared to control fish. The interplay between nanoparticle exposure, immune system, histopathology, and infectious disease pathogenesis in any animal model has not been described before. By modulating fish immune responses and interfering with resistance to bacterial pathogens, manufactured nano-TiO2 has the potential to affect fish survival in a disease outbreak. - Highlights: • First data on the effect of nano-TiO2 pre-exposure on responses to bacterial pathogens. • Interplay between nano-TiO2, immune system, histopathology, and bacteria is described. • Nano-TiO2 has the potential to affect fish population survival in a disease outbreak. - By modulating fish immune responses and interfering with resistance to bacterial pathogens, internalized environmentally relevant concentrations of nano-TiO2 have potential to increase mortality of fish exposed to infectious disease challenge

  3. The type III secretion system apparatus determines the intracellular niche of bacterial pathogens.

    Science.gov (United States)

    Du, Juan; Reeves, Analise Z; Klein, Jessica A; Twedt, Donna J; Knodler, Leigh A; Lesser, Cammie F

    2016-04-26

    Upon entry into host cells, intracellular bacterial pathogens establish a variety of replicative niches. Although some remodel phagosomes, others rapidly escape into the cytosol of infected cells. Little is currently known regarding how professional intracytoplasmic pathogens, including Shigella, mediate phagosomal escape. Shigella, like many other Gram-negative bacterial pathogens, uses a type III secretion system to deliver multiple proteins, referred to as effectors, into host cells. Here, using an innovative reductionist-based approach, we demonstrate that the introduction of a functional Shigella type III secretion system, but none of its effectors, into a laboratory strain of Escherichia coli is sufficient to promote the efficient vacuole lysis and escape of the modified bacteria into the cytosol of epithelial cells. This establishes for the first time, to our knowledge, a direct physiologic role for the Shigella type III secretion apparatus (T3SA) in mediating phagosomal escape. Furthermore, although protein components of the T3SA share a moderate degree of structural and functional conservation across bacterial species, we show that vacuole lysis is not a common feature of T3SA, as an effectorless strain of Yersinia remains confined to phagosomes. Additionally, by exploiting the functional interchangeability of the translocator components of the T3SA of Shigella, Salmonella, and Chromobacterium, we demonstrate that a single protein component of the T3SA translocon-Shigella IpaC, Salmonella SipC, or Chromobacterium CipC-determines the fate of intracellular pathogens within both epithelial cells and macrophages. Thus, these findings have identified a likely paradigm by which the replicative niche of many intracellular bacterial pathogens is established. PMID:27078095

  4. Structure-Activity Relationships of Antimicrobial Gallic Acid Derivatives from Pomegranate and Acacia Fruit Extracts against Potato Bacterial Wilt Pathogen.

    Science.gov (United States)

    Farag, Mohamed A; Al-Mahdy, Dalia A; Salah El Dine, Riham; Fahmy, Sherifa; Yassin, Aymen; Porzel, Andrea; Brandt, Wolfgang

    2015-06-01

    Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc-zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity-guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5-dihydroxy-4-methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5-9 mg/ml), with 3,5-dihydroxy-4-methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure-activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids. PMID:26080741

  5. Cytotoxic chromosomal targeting by CRISPR/Cas systems can reshape bacterial genomes and expel or remodel pathogenicity islands.

    Directory of Open Access Journals (Sweden)

    Reuben B Vercoe

    2013-04-01

    Full Text Available In prokaryotes, clustered regularly interspaced short palindromic repeats (CRISPRs and their associated (Cas proteins constitute a defence system against bacteriophages and plasmids. CRISPR/Cas systems acquire short spacer sequences from foreign genetic elements and incorporate these into their CRISPR arrays, generating a memory of past invaders. Defence is provided by short non-coding RNAs that guide Cas proteins to cleave complementary nucleic acids. While most spacers are acquired from phages and plasmids, there are examples of spacers that match genes elsewhere in the host bacterial chromosome. In Pectobacterium atrosepticum the type I-F CRISPR/Cas system has acquired a self-complementary spacer that perfectly matches a protospacer target in a horizontally acquired island (HAI2 involved in plant pathogenicity. Given the paucity of experimental data about CRISPR/Cas-mediated chromosomal targeting, we examined this process by developing a tightly controlled system. Chromosomal targeting was highly toxic via targeting of DNA and resulted in growth inhibition and cellular filamentation. The toxic phenotype was avoided by mutations in the cas operon, the CRISPR repeats, the protospacer target, and protospacer-adjacent motif (PAM beside the target. Indeed, the natural self-targeting spacer was non-toxic due to a single nucleotide mutation adjacent to the target in the PAM sequence. Furthermore, we show that chromosomal targeting can result in large-scale genomic alterations, including the remodelling or deletion of entire pre-existing pathogenicity islands. These features can be engineered for the targeted deletion of large regions of bacterial chromosomes. In conclusion, in DNA-targeting CRISPR/Cas systems, chromosomal interference is deleterious by causing DNA damage and providing a strong selective pressure for genome alterations, which may have consequences for bacterial evolution and pathogenicity.

  6. Capture and concentration of viral and bacterial foodborne pathogens using apolipoprotein H.

    Science.gov (United States)

    Almand, Erin A; Goulter, Rebecca M; Jaykus, Lee-Ann

    2016-09-01

    The need for improved pathogen separation and concentration methods to reduce time-to-detection for foodborne pathogens is well recognized. Apolipoprotein H (ApoH) is an acute phase human plasma protein that has been previously shown to interact with viruses, lipopolysaccharides (LPS) and bacterial proteins. The purpose of this study was to determine if ApoH was capable of binding and efficiently capturing two representative human norovirus strains (GI.1 and GII.4), a cultivable surrogate, and four bacterial pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus). Experiments were carried out using an ApoH-conjugated magnetic bead-based capture followed by pathogen detection using nucleic acid amplification. For all three viruses studied, >10% capture efficiency (microflora. A complementary plate-based capture assay showed that ApoH bound to a variety of human norovirus virus-like particles. ApoH has the potential to be a broadly reactive ligand for separating and concentrating representative foodborne pathogens, both bacteria and viruses. PMID:27439140

  7. Benfang Lei’s research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis

    Directory of Open Access Journals (Sweden)

    Benfang Lei

    2010-09-01

    Full Text Available Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS and horse pathogen Streptococcus equi (S. equi. His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S. equi pathogenesis. Heme is an important source of essential iron for bacterial pathogens. Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS, demonstrated direct heme transfer from one protein to another, demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system, elucidated the activated heme transfer mechanism, and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction. These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Gram-positive pathogens. Pathogenesis of GAS is mediated by an abundance of extracellular proteins, and pathogenic role and functional mechanism are not known for many of these virulence factors. Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination. These studies may lead to development of novel strategies to prevent and treat GAS infections.

  8. Benfang Lei’s research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS)and horse pathogen Streptococcus equi(S.equi). His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S.equi pathogenesis.Heme is an important source of essential iron for bacterial pathogens.Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS,demonstrated direct heme transfer from one protein to another,demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system,elucidated the activated heme transfer mechanism,and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction.These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Grampositive pathogens.Pathogenesis of GAS is mediated by an abundance of extracellular proteins,and pathogenic role and functional mechanism are not known for many of these virulence factors.Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination.These studies may lead to development of novel strategies to prevent and treat GAS infections.

  9. In Vitro Antibacterial Spectrum of Sodium Selenite against Selected Human Pathogenic Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Mohammad Firoz Alam

    2016-01-01

    Full Text Available The objective of this investigation was to predict the antibacterial properties of sodium selenite against selected human pathogens. A group of six human bacterial pathogens including Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella planticola were utilized for screening. The spectrum of activity was qualified based on zone of inhibition. Our study demonstrated that sodium selenite exhibits a strong spectrum of activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Klebsiella planticola. The spectrum of activity was compared with standard ciprofloxacin disc (5 μg/disc and observed to have satisfactory effect.

  10. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    Directory of Open Access Journals (Sweden)

    Carl A. Batt

    2009-05-01

    Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

  11. Unravelling Linkages between Plant Community Composition and the Pathogen-Suppressive Potential of Soils.

    Science.gov (United States)

    Latz, Ellen; Eisenhauer, Nico; Rall, Björn Christian; Scheu, Stefan; Jousset, Alexandre

    2016-01-01

    Plant diseases cause dramatic yield losses worldwide. Current disease control practices can be deleterious for the environment and human health, calling for alternative and sustainable management regimes. Soils harbour microorganisms that can efficiently suppress pathogens. Uncovering mediators driving their functioning in the field still remains challenging, but represents an essential step in order to develop strategies for increased soil health. We set up plant communities of varying richness to experimentally test the potential of soils differing in plant community history to suppress the pathogen Rhizoctonia solani. The results indicate that plant communities shape soil-disease suppression via changes in abiotic soil properties and the abundance of bacterial groups including species of the genera Actinomyces, Bacillus and Pseudomonas. Further, the results suggest that pairwise interactions between specific plant species strongly affect soil suppressiveness. Using structural equation modelling, we provide a pathway orientated framework showing how the complex interactions between plants, soil and microorganisms jointly shape soil suppressiveness. Our results stress the importance of plant community composition as a determinant of soil functioning, such as the disease suppressive potential of soils. PMID:27021053

  12. Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions.

    Science.gov (United States)

    D'Alessandro, Marco; Erb, Matthias; Ton, Jurriaan; Brandenburg, Anna; Karlen, Danielle; Zopfi, Jakob; Turlings, Ted C J

    2014-04-01

    Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3-butanediol (2,3-BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3-BD in the headspace of soil-grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3-BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes-inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3-BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3-BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3-BD on the parasitoid is indirect and depends on the composition of the microbial community. PMID:24127750

  13. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  14. EFFECTS OF COMPOSTED MUNICIPAL SLUDGE ON SOILBORNE PLANT PATHOGENS

    Science.gov (United States)

    The effect of composted municipal sludge (CMS) on soilborne plant pathogens was evaluated in three sets of experiments. Studies with soybeans over three growing seasons investigated the effect of CMS on root rot severity and yield in Phytophthora-infested soil, the effect of appl...

  15. Nutrient acquisition and secondary metabolites in plant pathogenic fungi

    DEFF Research Database (Denmark)

    Droce, Aida

    Fusarium graminearum is a necrotrophic plant pathogen that leads to severe infections of cereals contaminating them with mycotoxins harmful to human and animal. Blumeria graminis f. sp. hordei is an obligate biotroph that causes powdery mildew infections of barley. In this thesis, lifecycles and ...

  16. An Alternative Efficient Procedure for Purification of the Obligate Intracellular Fish Bacterial Pathogen Piscirickettsia salmonis

    OpenAIRE

    Henríquez, Vitalia; Rojas, María Verónica; Marshall, Sergio H.

    2003-01-01

    Piscirickettsia salmonis is an obligate intracellular bacterial pathogen of salmonid fish and the etiological agent of the aggressive disease salmonid rickettsial syndrome. Today, this disease, also known as piscirickettsiosis, is the cause of high mortality in net pen-reared salmonids in southern Chile. Although the bacteria can be grown in tissue culture cells, genetic analysis of the organism has been hindered because of the difficulty in obtaining P. salmonis DNA free from contaminating h...

  17. Fluorescence in situ hybridization for the tissue detection of bacterial pathogens associated with porcine infections

    DEFF Research Database (Denmark)

    Jensen, Henrik Elvang; Jensen, Louise Kruse; Barington, Kristiane;

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  18. Fluorescence In Situ Hybridization for the Tissue Detection of Bacterial Pathogens Associated with Porcine Infections

    DEFF Research Database (Denmark)

    Elvang Jensen, Henrik; Jensen, Louise Kruse; Barington, Kristiane;

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  19. Interactions among Strategies Associated with Bacterial Infection: Pathogenicity, Epidemicity, and Antibiotic Resistance†

    OpenAIRE

    Martínez, José L.; Baquero, Fernando

    2002-01-01

    Infections have been the major cause of disease throughout the history of human populations. With the introduction of antibiotics, it was thought that this problem should disappear. However, bacteria have been able to evolve to become antibiotic resistant. Nowadays, a proficient pathogen must be virulent, epidemic, and resistant to antibiotics. Analysis of the interplay among these features of bacterial populations is needed to predict the future of infectious diseases. In this regard, we hav...

  20. Inducible Resistance of Fish Bacterial Pathogens to the Antimicrobial Peptide Cecropin B▿

    OpenAIRE

    Sallum, Ulysses W.; Chen, Thomas T

    2008-01-01

    Cecropin B is a cationic antimicrobial peptide originally isolated from the diapausing pupae of the giant silk moth, Hylphora cecropia. Cecropin B elicits its antimicrobial effects through disruption of the anionic cell membranes of gram-negative bacteria. Previous work by our laboratory demonstrated that a constitutively expressed cecropin B transgene conferred enhanced resistance to bacterial infection in medaka. The development of antibiotic resistance by pathogenic bacteria is a growing p...

  1. Effects of Benzalkonium Chloride on Planktonic Growth and Biofilm Formation by Animal Bacterial Pathogens

    OpenAIRE

    Ebrahimi, Azizollah; Hemati, Majid; Shabanpour, Ziba; Habibian Dehkordi, Saeed; BAHADORAN, Shahab; Lotfalian, Sharareh; Khubani, Shahin

    2015-01-01

    Background: Resistance toward quaternary ammonium compounds (QACs) is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as biofilm formation. Objectives: In this study, the effects of benzalkonium chloride on planktonic growth and biofilm formation by some field isolates of animal bacterial pathogens were investigated. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus aureus and Streptococcus...

  2. Convergent use of RhoGAP toxins by eukaryotic parasites and bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Dominique Colinet

    2007-12-01

    Full Text Available Inactivation of host Rho GTPases is a widespread strategy employed by bacterial pathogens to manipulate mammalian cellular functions and avoid immune defenses. Some bacterial toxins mimic eukaryotic Rho GTPase-activating proteins (GAPs to inactivate mammalian GTPases, probably as a result of evolutionary convergence. An intriguing question remains whether eukaryotic pathogens or parasites may use endogenous GAPs as immune-suppressive toxins to target the same key genes as bacterial pathogens. Interestingly, a RhoGAP domain-containing protein, LbGAP, was recently characterized from the parasitoid wasp Leptopilina boulardi, and shown to protect parasitoid eggs from the immune response of Drosophila host larvae. We demonstrate here that LbGAP has structural characteristics of eukaryotic RhoGAPs but that it acts similarly to bacterial RhoGAP toxins in mammals. First, we show by immunocytochemistry that LbGAP enters Drosophila immune cells, plasmatocytes and lamellocytes, and that morphological changes in lamellocytes are correlated with the quantity of LbGAP they contain. Demonstration that LbGAP displays a GAP activity and specifically interacts with the active, GTP-bound form of the two Drosophila Rho GTPases Rac1 and Rac2, both required for successful encapsulation of Leptopilina eggs, was then achieved using biochemical tests, yeast two-hybrid analysis, and GST pull-down assays. In addition, we show that the overall structure of LbGAP is similar to that of eukaryotic RhoGAP domains, and we identify distinct residues involved in its interaction with Rac GTPases. Altogether, these results show that eukaryotic parasites can use endogenous RhoGAPs as virulence factors and that despite their differences in sequence and structure, eukaryotic and bacterial RhoGAP toxins are similarly used to target the same immune pathways in insects and mammals.

  3. Pathogenicity of some bacterial species isolated from the bee digestive tract

    Directory of Open Access Journals (Sweden)

    Dugalić-Vrndić Nada

    2010-01-01

    Full Text Available The aim of this paper was to examine the pathogenicity of most commonly isolated bacteria from the digestive tract of bees. Bees from 150 colonies (n=3000 were examined and 19 bacterial species were isolated, which are either permanent or temporary inhabitants of the digestive tract. Pathogenic activity of the most commonly isolated species (Enterobacter aerogenes, Klebsiella ozaenae, Klebsiella pneumonie, Citrobacter freundii, Enterobacter cloacae and Enterobacter agglomerans was examined on seven-day-old chicken embryos and tissue of MDBK cells. Bacterial inoculation of the examined bacteria was conducted in the alantoic cavity of chicken embryos in the quantity of 0.5 mL. Control noninoculated and inoculated embryos were incubated at 38oC with about 60% relative humidity. All six bacterial species manifested pathogenic activity on chicken embryos and caused their death within 2-4 days and changes such as lagging in embryo development, bleeding and unpleasant smell. The bacteria examined in MDBK cell lines of bovine kidney tissue did not manifest cytopathogenic effect and the structure of control tissue was normal.

  4. Bacteriocin from Bacillus subtilis as a novel drug against diabetic foot ulcer bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Baby Joseph; Berlina Dhas; Vimalin Hena; Justin Raj

    2013-01-01

    Objective:To isolate and identify Bacillus subtilis (B. subtilis) from soil and to characterize and partially purify the bacteriocin. To evaluate the antimicrobial activity against four diabetic foot ulcer bacterial pathogens. Methods:Genotypic identification was done based on Bergey’s manual of systemic bacteriology. Antimicrobial susceptibility test was done by Kirby-Bauer disc diffusion method. Colonies were identified by colony morphology and biochemical characterization and also compared with MTCC 121 strain. Further identification was done by 16S rRNA sequencing. Inhibitory activities of partially purified bacteriocin on all the DFU isolates were done by agar well diffusion method. The strain was identified to produce bacteriocin by stab overlay assay. Bacteriocin was extracted by organic solvent extraction using chloroform, further purified by HPLC and physical, and chemical characterization was performed. Results: The four isolates showed high level of resistance to amoxyclav and sensitivity to ciprofloxacin. HPLC purification revealed that the extracts are bacteriocin. The phylogenetic tree analysis results showed that the isolate was 99%related to B. subtilis BSF01. The results reveled activity to all the four isolates and high level of activity was seen in case of Klebsiella sp. Conclusions:Partially purified bacteriocin was found to have antimicrobial activity against the four diabetic foot ulcer bacterial pathogens, which can thus be applied as a better drug molecule on further studies. The strain B. subtilis are found to be safe for use and these antimicrobial peptides can be used as an antimicrobial in humans to treat DFU bacterial pathogens.

  5. Insights into the emergent bacterial pathogen Cronobacter spp., generated by multilocus sequence typing and analysis

    Directory of Open Access Journals (Sweden)

    StephenForsythe

    2012-11-01

    Full Text Available Cronobacter spp. (previously known as Enterobacter sakazakii is a bacterial pathogen affecting all age groups, with particularly severe clinical complications in neonates and infants. One recognised route of infection being the consumption of contaminated infant formula. As a recently recognised bacterial pathogen of considerable importance and regulatory control, appropriate detection and identification schemes are required. The application of multilocus sequence typing (MLST and analysis (MLSA of the seven alleles atpD, fusA, glnS, gltB, gyrB, infB and ppsA (concatenated length 3036 base pairs has led to considerable advances in our understanding of the genus. This approach is supported by both the reliability of DNA sequencing over subjective phenotyping and the establishment of a MLST database which has open access and is also curated; http://www.pubMLST.org/cronobacter. MLST has been used to describe the diversity of the newly recognised genus, instrumental in the formal recognition of new Cronobacter species (C. universalis and C. condimenti and revealed the high clonality of strains and the association of clonal complex 4 with neonatal meningitis cases. Clearly the MLST approach has considerable benefits over the use of non-DNA sequence based methods of analysis for newly emergent bacterial pathogens. The application of MLST and MLSA has dramatically enabled us to better understand this opportunistic bacterium which can cause irreparable damage to a newborn baby’s brain, and has contributed to improved control measures to protect neonatal health.

  6. Exposure to viral and bacterial pathogens among Soay sheep (Ovis aries) of the St Kilda archipelago.

    Science.gov (United States)

    Graham, A L; Nussey, D H; Lloyd-Smith, J O; Longbottom, D; Maley, M; Pemberton, J M; Pilkington, J G; Prager, K C; Smith, L; Watt, K A; Wilson, K; McNEILLY, T N; Brülisauer, F

    2016-07-01

    We assessed evidence of exposure to viruses and bacteria in an unmanaged and long-isolated population of Soay sheep (Ovis aries) inhabiting Hirta, in the St Kilda archipelago, 65 km west of Benbecula in the Outer Hebrides of Scotland. The sheep harbour many metazoan and protozoan parasites but their exposure to viral and bacterial pathogens is unknown. We tested for herpes viral DNA in leucocytes and found that 21 of 42 tested sheep were infected with ovine herpesvirus 2 (OHV-2). We also tested 750 plasma samples collected between 1997 and 2010 for evidence of exposure to seven other viral and bacterial agents common in domestic Scottish sheep. We found evidence of exposure to Leptospira spp., with overall seroprevalence of 6·5%. However, serological evidence indicated that the population had not been exposed to border disease, parainfluenza, maedi-visna, or orf viruses, nor to Chlamydia abortus. Some sheep tested positive for antibodies against Mycobacterium avium subsp. paratuberculosis (MAP) but, in the absence of retrospective faecal samples, the presence of this infection could not be confirmed. The roles of importation, the pathogen-host interaction, nematode co-infection and local transmission warrant future investigation, to elucidate the transmission ecology and fitness effects of the few viral and bacterial pathogens on Hirta. PMID:26829883

  7. Harpinxoo and Its Functional Domains Activate Pathogen-inducible Plant Promoters in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    PENGJian-Ling; BAOZhi-Long; LIPing; CHENGuang-Yong; WANGJin-Sheng; DONGHan-Song

    2004-01-01

    Harpins are bacterial proteins that can enhance plant growth and defense against pathogens and insects. To elaborate whether harpins perform the diverse functions in coordination with the activation of specific promoters that contain particular elements, we cloned pathogen-inducible plant promoters PPP1, PPP2, and PPP3 from tobacco and investigated their responses to harpinxoo or its truncated fragments DEG, DIR, and DPR (domains for enhancing plant growth, insect resistance and pathogen resistance). PPP1 contains an internal repeat composed of two tandem 111bp fragments; 111bp in the repeat was deleted in PPP2. PPP3 contains a bacteria-inducible element; PPP1 and PPP2 additionally contain TAC-1 and Eli boxes inducible correspondingly by salicylic acid (SA) and elicitors. Function of cloned PPPs was confirmed based on their activation in transgenic Arabidopsis plants by Ralstonia solanacearum (Ralston) or SA. Harpinxoo, DEG, DIR, or DPR activated PPP1 and PPP2 but not PPP3, consistent with the presence of Eli boxes in promoters. PPP1 was ca. 3-fold more active than PPP2, suggesting that the internal repeat affects levels of the promoter activation.

  8. Methylobacterium-induced endophyte community changes correspond with protection of plants against pathogen attack.

    Directory of Open Access Journals (Sweden)

    Pavlo Ardanov

    Full Text Available Plant inoculation with endophytic bacteria that normally live inside the plant without harming the host is a highly promising approach for biological disease control. The mechanism of resistance induction by beneficial bacteria is poorly understood, because pathways are only partly known and systemic responses are typically not seen. The innate endophytic community structures change in response to external factors such as inoculation, and bacterial endophytes can exhibit direct or indirect antagonism towards pathogens. Earlier we showed that resistance induction by an endophytic Methylobacterium sp. in potato towards Pectobacterium atrosepticum was dependent on the density of the inoculum, whereas the bacterium itself had no antagonistic activity. To elucidate the role of innate endophyte communities in plant responses, we studied community changes in both in vitro and greenhouse experiments using various combinations of plants, endophyte inoculants, and pathogens. Induction of resistance was studied in several potato (Solanum tuberosum L. cultivars by Methylobacterium sp. IMBG290 against the pathogens P. atrosepticum, Phytophthora infestans and Pseudomonas syringae pv. tomato DC3000, and in pine (Pinus sylvestris L. by M. extorquens DSM13060 against Gremmeniella abietina. The capacities of the inoculated endophytic Methylobacterium spp. strains to induce resistance were dependent on the plant cultivar, pathogen, and on the density of Methylobacterium spp. inoculum. Composition of the endophyte community changed in response to inoculation in shoot tissues and correlated with resistance or susceptibility to the disease. Our results demonstrate that endophytic Methylobacterium spp. strains have varying effects on plant disease resistance, which can be modulated through the endophyte community of the host.

  9. Foodborne Pathogens Prevention and Sensory Attributes Enhancement in Processed Cheese via Flavoring with Plant Extracts.

    Science.gov (United States)

    Tayel, Ahmed A; Hussein, Heba; Sorour, Noha M; El-Tras, Wael F

    2015-12-01

    Cheese contaminations with foodborne bacterial pathogens, and their health outbreaks, are serious worldwide problems that could happen from diverse sources during cheese production or storage. Plants, and their derivatives, were always regarded as the potential natural and safe antimicrobial alternatives for food preservation and improvement. The extracts from many plants, which are commonly used as spices and flavoring agents, were evaluated as antibacterial agents against serious foodborne pathogens, for example Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus, and Escherichia coli O157:H7, using qualitative and quantitative assaying methods. Dairy-based media were also used for evaluating the practical application of plant extracts as antimicrobial agents. Most of the examined plant extracts exhibited remarkable antibacterial activity; the extracts of cinnamon, cloves, garden cress, and lemon grass were the most powerful, either in synthetic or in dairy-based media. Flavoring processed cheese with plant extracts resulted in the enhancement of cheese sensory attributes, for example odor, taste, color, and overall quality, especially in flavored samples with cinnamon, lemon grass, and oregano. It can be concluded that plant extracts are strongly recommended, as powerful and safe antibacterial and flavoring agents, for the preservation and sensory enhancement of processed cheese. PMID:26540146

  10. List of New Names of Plant Pathogenic Bacteria (2008-2010)

    Science.gov (United States)

    In 2010 the International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria published the Comprehensive List of Names of Plant Pathogenic Bacteria, 1980-2007 to provide an authoritative register of names of plant pathogens. In this manuscript we up-date the list of na...

  11. Transcriptomic changes in the plant pathogenic fungus Rhizoctonia solani AG-3 in response to the antagonistic bacteria Serratia proteamaculans and Serratia plymuthica

    OpenAIRE

    Gkarmiri, Konstantia; Finlay, Roger D.; Alström, Sadhna; Thomas, Elizabeth; Cubeta, Marc A.; Högberg, Nils

    2015-01-01

    Background Improved understanding of bacterial-fungal interactions in the rhizosphere should assist in the successful application of bacteria as biological control agents against fungal pathogens of plants, providing alternatives to chemicals in sustainable agriculture. Rhizoctonia solani is an important soil-associated fungal pathogen and its chemical treatment is not feasible or economic. The genomes of the plant-associated bacteria Serratia proteamaculans S4 and Serratia plymuthica AS13 ha...

  12. Digital Processing of Light Microscopy Images in Plant Pathogen Diagnostics

    Czech Academy of Sciences Publication Activity Database

    Sedlář, Jiří; Sedlářová, M.; Flusser, Jan

    Santa Barbara : Center for Bio-Image Informatics, 2008, s. 1-2. [Workshop on Bio-Image Informatics: Biological Imaging, Computer Vision and Data Mining, 2008. Santa Barbara, CA (US), 17.01.2008-18.01.2008] R&D Projects: GA MŠk 1M0572 Grant ostatní: GA UK(CZ) 148207 Institutional research plan: CEZ:AV0Z10750506 Keywords : image processing * pattern recognition * downy mildews * light microscopy * pathogen determination Subject RIV: IN - Informatics, Computer Science http://library.utia.cas.cz/separaty/2008/ZOI/sedlar-digital processing of light microscopy images in plant pathogen diagnostics.pdf

  13. BIOLOGICAL CONTROL OF WEEDS BY MEANS OF PLANT PATHOGENS

    Directory of Open Access Journals (Sweden)

    Marija Ravlić

    2014-06-01

    Full Text Available Biological control is the use of live beneficial organisms and products of their metabolism in the pests control. Plant pathogens can be used for weed control in three different ways: as classical, conservation and augmentative (inoculative and inundated biological control. Inundated biological control involves the use of bioherbicides (mycoherbicides or artificial breeding of pathogens and application in specific stages of crops and weeds. Biological control of weeds can be used where chemical herbicides are not allowed, if resistant weed species are present or in the integrated pest management against weeds with reduced herbicides doses and other non-chemical measures, but it has certain limitations and disadvantages.

  14. Bulk and Rhizosphere Soil Bacterial Communities Studied by Denaturing Gradient Gel Electrophoresis: Plant-Dependent Enrichment and Seasonal Shifts Revealed

    OpenAIRE

    Smalla, K.; Wieland, G.; Buchner, A.; A. Zock; Parzy, J.; Kaiser, S; Roskot, N.; Heuer, H.; Berg, G

    2001-01-01

    The bacterial rhizosphere communities of three host plants of the pathogenic fungus Verticillium dahliae, field-grown strawberry (Fragaria ananassa Duch.), oilseed rape (Brassica napus L.), and potato (Solanum tuberosum L.), were analyzed. We aimed to determine the degree to which the rhizosphere effect is plant dependent and whether this effect would be increased by growing the same crops in two consecutive years. Rhizosphere or soil samples were taken five times over the vegetation periods....

  15. A fungal pathogen secretes plant alkalinizing peptides to increase infection.

    Science.gov (United States)

    Masachis, Sara; Segorbe, David; Turrà, David; Leon-Ruiz, Mercedes; Fürst, Ursula; El Ghalid, Mennat; Leonard, Guy; López-Berges, Manuel S; Richards, Thomas A; Felix, Georg; Di Pietro, Antonio

    2016-01-01

    Plant infections caused by fungi are often associated with an increase in the pH of the surrounding host tissue(1). Extracellular alkalinization is thought to contribute to fungal pathogenesis, but the underlying mechanisms are poorly understood. Here, we show that the root-infecting fungus Fusarium oxysporum uses a functional homologue of the plant regulatory peptide RALF (rapid alkalinization factor)(2,3) to induce alkalinization and cause disease in plants. An upshift in extracellular pH promotes infectious growth of Fusarium by stimulating phosphorylation of a conserved mitogen-activated protein kinase essential for pathogenicity(4,5). Fungal mutants lacking a functional Fusarium (F)-RALF peptide failed to induce host alkalinization and showed markedly reduced virulence in tomato plants, while eliciting a strong host immune response. Arabidopsis plants lacking the receptor-like kinase FERONIA, which mediates the RALF-triggered alkalinization response(6), displayed enhanced resistance against Fusarium. RALF homologues are found across a number of phylogenetically distant groups of fungi, many of which infect plants. We propose that fungal pathogens use functional homologues of alkalinizing peptides found in their host plants to increase their infectious potential and suppress host immunity. PMID:27572834

  16. Bacterial endosymbionts of plant-parasitic nematodes

    Science.gov (United States)

    Several groups of bacteria have been reported as endosymbionts of various orders of nematodes including the filarial nematodes (Brugia malayi, Wucheria bancrofti and Onchocerca volvulus (Spiruida)), the entomopathogenic nematodes (Steinernema spp., and Heterorhabditis spp. (Rhabditida)), and plant-p...

  17. Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily.

    Science.gov (United States)

    Matsunaga, James; Barocchi, Michele A; Croda, Julio; Young, Tracy A; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A; Reis, Mitermayer G; Riley, Lee W; Haake, David A; Ko, Albert I

    2003-08-01

    Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudogene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis. PMID:12890019

  18. Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi

    Directory of Open Access Journals (Sweden)

    Bergstrom Gary C

    2011-02-01

    Full Text Available Abstract Background The discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for the production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly cellulolytic and is a major industrial microbial source for commercial cellulases, xylanases and other cell wall degrading enzymes. However, enzyme-prospecting research continues to identify opportunities to enhance the activity of T. reesei enzyme preparations by supplementing with enzymatic diversity from other microbes. The goal of this study was to evaluate the enzymatic potential of a broad range of plant pathogenic and non-pathogenic fungi for their ability to degrade plant biomass and isolated polysaccharides. Results Large-scale screening identified a range of hydrolytic activities among 348 unique isolates representing 156 species of plant pathogenic and non-pathogenic fungi. Hierarchical clustering was used to identify groups of species with similar hydrolytic profiles. Among moderately and highly active species, plant pathogenic species were found to be more active than non-pathogens on six of eight substrates tested, with no significant difference seen on the other two substrates. Among the pathogenic fungi, greater hydrolysis was seen when they were tested on biomass and hemicellulose derived from their host plants (commelinoid monocot or dicot. Although T. reesei has a hydrolytic profile that is highly active on cellulose and pretreated biomass, it was less active than some natural isolates of fungi when tested on xylans and untreated biomass. Conclusions Several highly active isolates of plant pathogenic fungi were identified, particularly when tested on xylans and untreated biomass. There were statistically significant preferences for biomass type reflecting the monocot or dicot host preference of the

  19. A family of conserved bacterial effectors inhibits salicylic acid-mediated basal immunity and promotes disease necrosis in plants.

    Science.gov (United States)

    DebRoy, Sruti; Thilmony, Roger; Kwack, Yong-Bum; Nomura, Kinya; He, Sheng Yang

    2004-06-29

    Salicylic acid (SA)-mediated host immunity plays a central role in combating microbial pathogens in plants. Inactivation of SA-mediated immunity, therefore, would be a critical step in the evolution of a successful plant pathogen. It is known that mutations in conserved effector loci (CEL) in the plant pathogens Pseudomonas syringae (the Delta CEL mutation), Erwinia amylovora (the dspA/E mutation), and Pantoea stewartii subsp. stewartii (the wtsE mutation) exert particularly strong negative effects on bacterial virulence in their host plants by unknown mechanisms. We found that the loss of virulence in Delta CEL and dspA/E mutants was linked to their inability to suppress cell wall-based defenses and to cause normal disease necrosis in Arabidopsis and apple host plants. The Delta CEL mutant activated SA-dependent callose deposition in wild-type Arabidopsis but failed to elicit high levels of callose-associated defense in Arabidopsis plants blocked in SA accumulation or synthesis. This mutant also multiplied more aggressively in SA-deficient plants than in wild-type plants. The hopPtoM and avrE genes in the CEL of P. syringae were found to encode suppressors of this SA-dependent basal defense. The widespread conservation of the HopPtoM and AvrE families of effectors in various bacteria suggests that suppression of SA-dependent basal immunity and promotion of host cell death are important virulence strategies for bacterial infection of plants. PMID:15210989

  20. Ingestion of a marked bacterial pathogen of cotton conclusively demonstrates feeding by first instar southern green stink bug (Hemiptera: Pentatomidae).

    Science.gov (United States)

    Esquivel, J F; Medrano, E G

    2014-02-01

    Long-held dogma dictates that first instars of Nezara viridula (L.) do not feed, yet recent observations of stylet activity within a food source suggest otherwise. As a cosmopolitan pest of cotton and other high-value cash crops, confirmation of feeding by first instars may ultimately influence the knowledge on biology and management strategies for this pest. To determine whether first instars feed, newly hatched nymphs were provided sterile green beans (control) or beans infected with a rifampicin-resistant marked bacterial pathogen (Pantoea agglomerans (Ewing and Fife)) of cotton. Insects were exposed to beans for 2 d, and feeding was confirmed based on detection of marked bacteria ingested by the insect. Normal bacterial flora was detected in all insects; however, control insects did not possess the marked bacteria. Of the first instars surviving on infected beans, ≍65% possessed the marked bacteria internally. Furthermore, the frequency of insects with marked bacteria was higher in insects collected directly from the bean surface than those that were off the bean at time of collection. Densities of innate and marked bacteria were comparable (both ranging from 10(1) to 10(3)), suggesting that the marked bacteria did not exclude preexisting bacterial flora. Marked bacteria were also detected in a subset of second instars, indicating marked bacteria were retained through the molting process after ingesting bacteria as first instars. Our findings conclusively demonstrate feeding by first instars and redefine the long-held perspective of nonfeeding by first instars. These findings may necessitate changes to crop protection strategies against feeding and vectoring of plant pathogens by N. viridula. PMID:24342007

  1. Dietary plant phenolic improves survival of bacterial infection in Manduca sexta caterpillars.

    Science.gov (United States)

    Del Campo, Marta L; Halitschke, Rayko; Short, Sarah M; Lazzaro, Brian P; Kessler, André

    2013-03-01

    Plant phenolics are generally thought to play significant roles in plant defense against herbivores and pathogens. Many plant taxa, including Solanaceae, are rich in phenolic compounds and some insect herbivores have been shown to acquire phenolics from their hosts to use them as protection against their natural enemies. Here we demonstrate that larvae of an insect specialist on Solanaceae, the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae), acquire the plant phenolic chlorogenic acid (CA), and other caffeic acid derivatives as they feed on one of their hosts, Nicotiana attenuata L. (Solanaceae), and on artificial diet supplemented with CA. We test the hypothesis that larvae fed on CA-supplemented diet would have better resistance against bacterial infection than larvae fed on a standard CA-free diet by injecting bacteria into the hemocoel of fourth instars. Larvae fed CA-supplemented diet show significantly higher survival of infection with Enterococcus faecalis (Andrewes & Horder) Schleifer & Kilpper-Bälz, but not of infection with the more virulent Pseudomonas aeruginosa (Schroeter) Migula. Larvae fed on CA-supplemented diet possess a constitutively higher number of circulating hemocytes than larvae fed on the standard diet, but we found no other evidence of increased immune system activity, nor were larvae fed on CA-supplemented diet better able to suppress bacterial proliferation early in the infection. Thus, our data suggest an additional defensive function of CA to the direct toxic inhibition of pathogen proliferation in the gut. PMID:23420018

  2. Hemolysin, Protease, and EPS Producing Pathogenic Aeromonas hydrophila Strain An4 Shows Antibacterial Activity against Marine Bacterial Fish Pathogens

    Directory of Open Access Journals (Sweden)

    Anju Pandey

    2010-01-01

    Full Text Available A pathogenic Aeromonas hydrophila strain An4 was isolated from marine catfish and characterized with reference to its proteolytic and hemolytic activity along with SDS-PAGE profile (sodium dodecyl sulphate-Polyacrylamide gel electrophoresis of ECPs (extracellular proteins showing hemolysin (approximately 50 kDa. Agar well diffusion assay using crude cell extract of the bacterial isolate clearly demonstrated antibacterial activity against indicator pathogenic bacteria, Staphylococcus arlettae strain An1, Acinetobacter sp. strain An2, Vibrio parahaemolyticus strain An3, and Alteromonas aurentia SE3 showing inhibitory zone >10 mm well comparable to common antibiotics. Further GC-MS analysis of crude cell extract revealed several metabolites, namely, phenolics, pyrrolo-pyrazines, pyrrolo-pyridine, and butylated hydroxytoluene (well-known antimicrobials. Characterization of EPS using FTIR indicated presence of several protein-related amine and amide groups along with peaks corresponding to carboxylic and phenyl rings which may be attributed to its virulent and antibacterial properties, respectively. Besides hemolysin, EPS, and protease, Aeromonas hydrophila strain An4 also produced several antibacterial metabolites.

  3. Research of pathogenic bacteria and bacteriophages in the residuals of wastewater treatment plants

    International Nuclear Information System (INIS)

    The aim of this study is to find the pathogenic bacteria Listeria and Salmonella and to detect of bacterial (fecal coliforms) and viral indicators (bacteriophage) of fecal contamination in the residues of three sewage treatment plants in Greater Tunis: Charguia, Jdaida and Wardia. Three types of samples were analyzed: raw sewage, treated wastewater and sludge. The study showed the presence of pathogenic bacteria in some samples with a frequency of 7 pour cent for Listeria and 21 pour cent for Salmonella. However, none of these organisms has been detected in treated water of Jdaida and Chargia reflecting the efficiency of the purification process in these stations. Furthermore, all samples were positive for the presence of fecal coliforms and bacteriophages with important titles: up to 8.23 log10 (CFU/L) for coliforms and 8.36 log10 (pfu/L) for bacteriophages.

  4. Antibacterial activity of ethanolic extracts of selected medicinal plants against human pathogens

    Institute of Scientific and Technical Information of China (English)

    Renisheya Joy Jeba Malar T; Johnson M; Mary Uthith M; Arthy A

    2011-01-01

    Objective: To evaluate the antimicrobial potential of five medicinally important plants namely, Curcuma mangga (C. mangga) Valeton & Van Zijp, Ficus racemosa (F. racemosa) Roxb., Vitexnegundo (V. negundo) L., Ocimum basilicum (O. basilicum) L., and Etlingera elatior (E. elatior) K. Schum. against the human bacterial pathogens. Methods: The Klebsiella pneumonia (K.pneumonia ), Staphylococcus aureus (S. aureus) (ATCC 6538), Salmonella typhi (S. typhi) (MTCC 733), Proteus vulgaris (P. vulgaris), Pseudomonas aeruginosa (P. aeruginosa) were isolated from clinical samples. The bacteria were identified and confirmed by conventional microbiology procedure. Antimicrobial study was carried out by disc diffusion method against the pathogens by using the crude ethanolic extracts. Results: The results of the present study showed the presence of wide spectrum of antibacterial activities against all the above bacterial pathogens studied. The maximum zone of inhibition observed for each bacterium was as follows: S. typhi (12 mm), K. pneumonia (13 mm), P. vulgaris (20 mm), P. aeruginosa (16 mm) and S. aureus (12 mm).Conclusions:The present study demonstrates that the C. mangga, F. racemosa, V. negundo, O. basilicum, and E. elatior are potentially good sources of antibacterial agents against the pathogensviz., K. pneumonia, S. aureus, S. typhi, P. vulgaris and P. aeruginosa.

  5. Antifungal Activity of Some Extracts Against Some Plant Pathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Abdulrahman A. Aba AlKhail

    2005-01-01

    Full Text Available In vitro studies were carried out to determine the antifungal activity of five plant extracts viz., Allium sativum, Cymogopogon proxims, Carum carvi, Azadirchia indica and Eugenia caryophyllus extracted with either Cold Distilled Water (CDW, Boiling Distilled Water (BDW or Cold Ethanol (CET as well two culture filtrates of Trichoderma antagonistic fungi against Fusarium oxysporum f. sp. lycopersici, Botrytis cinerea and Rhizoctonia solani. The results revealed that plant extracts especially those extracted with CDW had strong antifungal activity with significant inhibition on the growth of the three tested fungi. In addition, the inhibitory magnitude of the tested plant extracts to the tested pathogen fungi was proportional to the applied concentrations. The most effective plant extracts were Allium sativum, Carum carvi and Eugenia caryophyllus. Also, the study showed that the culture filtrates of the antagonistic fungus, T. harzianum was more efficiency than T. viride to decrease the growth of tested fungi, but with levels less than plants extracted CDW or benomyl. Findings in this study confirmed that plant extracts can be used as natural fungicides to control pathogen fungi to reduce the dependence on the synthetic fungicides.

  6. Chlorhexidine Digluconate Effects on Planktonic Growth and Biofilm Formation in Some Field Isolates of Animal Bacterial Pathogens

    OpenAIRE

    Ebrahimi, Azizollah; Hemati, Majid; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Khoshnood, Sheida; Khubani, Shahin; Dokht Faraj, Mahdi; Hakimi Alni, Reza

    2014-01-01

    Background: To study chlorhexidine digluconate disinfectant effects on planktonic growth and biofilm formation in some bacterial field isolates from animals. Objectives: The current study investigated chlorhexidine digluconate effects on planktonic growth and biofilm formation in some field isolates of veterinary bacterial pathogens. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus. aureus and Streptococcus agalactiae (10 isolates for ea...

  7. Inhibitory Effect of Camptothecin against Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae RS-2.

    Science.gov (United States)

    Dong, Qiaolin; Luo, Ju; Qiu, Wen; Cai, Li; Anjum, Syed Ishtiaq; Li, Bin; Hou, Mingsheng; Xie, Guanlin; Sun, Guochang

    2016-01-01

    Camptothecin (CPT) has anticancer, antiviral, and antifungal properties. However, there is a dearth of information about antibacterial activity of CPT. Therefore, in this study, we investigated the inhibitory effect of CPT on Acidovorax avenae subsp. avenae strain RS-2, the pathogen of rice bacterial brown stripe, by measuring cell growth, DNA damage, cell membrane integrity, the expression of secretion systems, and topoisomerase-related genes, as well as the secretion of effector protein Hcp. Results indicated that CPT solutions at 0.05, 0.25, and 0.50 mg/mL inhibited the growth of strain RS-2 in vitro, while the inhibitory efficiency increased with an increase in CPT concentration, pH, and incubation time. Furthermore, CPT treatment affected bacterial growth and replication by causing membrane damage, which was evidenced by transmission electron microscopic observation and live/dead cell staining. In addition, quantitative real-time PCR analysis indicated that CPT treatment caused differential expression of eight secretion system-related genes and one topoisomerase-related gene, while the up-regulated expression of hcp could be justified by the increased secretion of Hcp based on the ELISA test. Overall, this study indicated that CPT has the potential to control the bacterial brown stripe pathogen of rice. PMID:27472315

  8. Comparison of individual and pooled sampling methods for detecting bacterial pathogens of fish

    Science.gov (United States)

    Mumford, Sonia; Patterson, Chris; Evered, J.; Brunson, Ray; Levine, J.; Winton, J.

    2005-01-01

    Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout (Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P sampling methods to permit detection of low-level bacterial infections of rainbow trout.

  9. A Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife.

    Directory of Open Access Journals (Sweden)

    Maria Razzauti

    Full Text Available Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq. In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454. In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles.We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of

  10. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Yamilé eLópez Hernández

    2015-02-01

    Full Text Available Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as a valuate tools to explore host-pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio, and non-vertebrate insects and nematodes (e.g. Caenorhabditis elegans in the study of diverse infectious agents that affect humans. Here we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favour of the use of these alternative animal models of infection to reveal the molecular signatures of host-pathogen interactions.

  11. Animals devoid of pulmonary system as infection models in the study of lung bacterial pathogens.

    Science.gov (United States)

    López Hernández, Yamilé; Yero, Daniel; Pinos-Rodríguez, Juan M; Gibert, Isidre

    2015-01-01

    Biological disease models can be difficult and costly to develop and use on a routine basis. Particularly, in vivo lung infection models performed to study lung pathologies use to be laborious, demand a great time and commonly are associated with ethical issues. When infections in experimental animals are used, they need to be refined, defined, and validated for their intended purpose. Therefore, alternative and easy to handle models of experimental infections are still needed to test the virulence of bacterial lung pathogens. Because non-mammalian models have less ethical and cost constraints as a subjects for experimentation, in some cases would be appropriated to include these models as valuable tools to explore host-pathogen interactions. Numerous scientific data have been argued to the more extensive use of several kinds of alternative models, such as, the vertebrate zebrafish (Danio rerio), and non-vertebrate insects and nematodes (e.g., Caenorhabditis elegans) in the study of diverse infectious agents that affect humans. Here, we review the use of these vertebrate and non-vertebrate models in the study of bacterial agents, which are considered the principal causes of lung injury. Curiously none of these animals have a respiratory system as in air-breathing vertebrates, where respiration takes place in lungs. Despite this fact, with the present review we sought to provide elements in favor of the use of these alternative animal models of infection to reveal the molecular signatures of host-pathogen interactions. PMID:25699030

  12. Molecular Epidemiologic Typing Systems of Bacterial Pathogens: Current Issues and Perpectives

    Directory of Open Access Journals (Sweden)

    Marc J Struelens

    1998-09-01

    Full Text Available The epidemiologic typing of bacterial pathogens can be applied to answer a number of different questions: in case of outbreak, what is the extent and mode of transmission of epidemic clone(s ? In case of long-term surveillance, what is the prevalence over time and the geographic spread of epidemic and endemic clones in the population? A number of molecular typing methods can be used to classify bacteria based on genomic diversity into groups of closely-related isolates (presumed to arise from a common ancestor in the same chain of transmission and divergent, epidemiologically-unrelated isolates (arising from independent sources of infection. Ribotyping, IS-RFLP fingerprinting, macrorestriction analysis of chromosomal DNA and PCR-fingerprinting using arbitrary sequence or repeat element primers are useful methods for outbreak investigations and regional surveillance. Library typing systems based on multilocus sequence-based analysis and strain-specific probe hybridization schemes are in development for the international surveillance of major pathogens like Mycobacterium tuberculosis. Accurate epidemiological interpretation of data obtained with molecular typing systems still requires additional research on the evolution rate of polymorphic loci in bacterial pathogens.

  13. The Top 10 oomycete pathogens in molecular plant pathology.

    Science.gov (United States)

    Kamoun, Sophien; Furzer, Oliver; Jones, Jonathan D G; Judelson, Howard S; Ali, Gul Shad; Dalio, Ronaldo J D; Roy, Sanjoy Guha; Schena, Leonardo; Zambounis, Antonios; Panabières, Franck; Cahill, David; Ruocco, Michelina; Figueiredo, Andreia; Chen, Xiao-Ren; Hulvey, Jon; Stam, Remco; Lamour, Kurt; Gijzen, Mark; Tyler, Brett M; Grünwald, Niklaus J; Mukhtar, M Shahid; Tomé, Daniel F A; Tör, Mahmut; Van Den Ackerveken, Guido; McDowell, John; Daayf, Fouad; Fry, William E; Lindqvist-Kreuze, Hannele; Meijer, Harold J G; Petre, Benjamin; Ristaino, Jean; Yoshida, Kentaro; Birch, Paul R J; Govers, Francine

    2015-05-01

    Oomycetes form a deep lineage of eukaryotic organisms that includes a large number of plant pathogens which threaten natural and managed ecosystems. We undertook a survey to query the community for their ranking of plant-pathogenic oomycete species based on scientific and economic importance. In total, we received 263 votes from 62 scientists in 15 countries for a total of 33 species. The Top 10 species and their ranking are: (1) Phytophthora infestans; (2, tied) Hyaloperonospora arabidopsidis; (2, tied) Phytophthora ramorum; (4) Phytophthora sojae; (5) Phytophthora capsici; (6) Plasmopara viticola; (7) Phytophthora cinnamomi; (8, tied) Phytophthora parasitica; (8, tied) Pythium ultimum; and (10) Albugo candida. This article provides an introduction to these 10 taxa and a snapshot of current research. We hope that the list will serve as a benchmark for future trends in oomycete research. PMID:25178392

  14. Bacterial anoxygenic photosynthesis on plant leaf surfaces

    Czech Academy of Sciences Publication Activity Database

    Atamna-Ismaeel, N.; Finkel, O.; Glaser, F.; von Mering, Ch.; Vorholt, J. A.; Koblížek, Michal; Belkin, S.; Béja, O.

    2012-01-01

    Roč. 4, č. 2 (2012), s. 209-216. ISSN 1758-2229 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0110; GA ČR GAP501/10/0221 Institutional support: RVO:61388971 Keywords : phyllosphere * plant * phyllosphere Subject RIV: EE - Microbiology, Virology Impact factor: 2.708, year: 2012

  15. Antifungal activity of aloe vera gel against plant pathogenic fungi

    International Nuclear Information System (INIS)

    Aloe vera gel extracted from the Aloe vera leaves was evaluated for their antifungal activity at the rate of 0.15%, 0.25% and 0.35% concentration against five plants pathogenic fungi viz., Aspergillus niger, Aspergillus flavus, Alternaria alternata, Drechslera hawaiensis and Penicillum digitatum 0.35% concentration Aloe vera gel completely inhibited the growth of Drechslera hawaiensis and Alternaria alternata. (author)

  16. Identification and Characterization of Bacterial Vaginosis-Associated Pathogens Using a Comprehensive Cervical-Vaginal Epithelial Coculture Assay

    OpenAIRE

    Eade, Colleen R.; Diaz, Camila; Wood, Matthew P.; Anastos, Kathryn; Patterson, Bruce K.; Gupta, Phalguni; Cole, Amy L.; Cole, Alexander M.

    2012-01-01

    Bacterial vaginosis (BV) is the most commonly treated female reproductive tract affliction, characterized by the displacement of healthy lactobacilli by an overgrowth of pathogenic bacteria. BV can contribute to pathogenic inflammation, preterm birth, and susceptibility to sexually transmitted infections. As the bacteria responsible for BV pathogenicity and their interactions with host immunity are not understood, we sought to evaluate the effects of BV-associated bacteria on reproductive epi...

  17. Detection of pathogenic clostridia in biogas plant wastes.

    Science.gov (United States)

    Neuhaus, Jürgen; Shehata, Awad A; Krüger, Monika

    2015-01-01

    As the number of biogas plants has grown rapidly in the last decade, the amount of potentially contaminated wastes with pathogenic Clostridium spp. has increased as well. This study reports the results from examining 203 biogas plant wastes (BGWs). The following Clostridium spp. with different frequencies could be isolated via a new enrichment medium (Krüne medium) and detected by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS): Clostridium perfringens (58 %) then Clostridium bifermentans (27 %), Clostridium tertium (23 %) and Clostridium butyricum (19 %), Clostridium cadaveris (15 %), Clostridium parapurificum (6 %), Clostridium glycolicum (5 %), Clostridium baratii (4 %), Clostridium sporogenes (2 %), Clostridium sordellii (1 %) and Clostridium subterminale (0.5 %). The mean most probable number (MPN) count of sulfite reducing bacteria was between 10(3) and 10(4)/mL, and the higher the MPN, the more pathogenic Clostridium spp. were present. Also, real-time PCR was used to be compared with culture method for C. perfringens, C. bifermentans, C. butyricum, C. sporogenes/Clostridium botulinum and C. sordellii. Although real-time PCR was more sensitive than the culture method, both systems improve the recovery rate but in different ways and are useful to determine pathogenic clostridia in biogas plants. In conclusion, BGWs could present a biohazard risk of clostridia for humans and animals. PMID:24984829

  18. Pathogen filtration to control plant disease outbreak in greenhouse production

    Science.gov (United States)

    Jeon, Sangho; Krasnow, Charles; Bhalsod, Gemini; Granke, Leah; Harlan, Blair; Hausbeck, Mary; Zhang, Wei

    2016-04-01

    Previous research has been extensively focused on understanding the fate and transport of human microbial pathogens in soil and water environments. However, little is known about the transport of plant pathogens, although these pathogens are often found in irrigation waters and could cause severe crop damage and economical loss. Water mold pathogens including Phytophthora spp. and Pythium spp. are infective to a wide range of vegetable and floriculture crops, and they are primarily harbored in soils and disseminated through water flow. It is challenging to control these pathogens because they often quickly develop resistance to many fungicides. Therefore, this multi-scale study aimed to investigate physical removal of plant pathogens from water by filtration, thus reducing the pathogen exposure risks to crops. In column-scale experiments, we studied controlling factors on the transport and retention of Phytophthora capsici zoospores in saturated columns packed with iron oxide coated-sand and uncoated-sand under varying solution chemistry. Biflagellate zoospores were less retained than encysted zoospores, and lower solution pH and greater iron oxide content increased the retention of encysted zoospores. These results provided insights on environmental dispersal of Phytophthora zoospores in natural soils as well as on developing cost-effective engineered filtration systems for pathogen removal. Using small-scale greenhouse filtration systems, we further investigated the performance of varying filter media (i.e., granular sand, iron oxide coated ceramic porous media, and activated carbon) in mitigating disease outbreaks of Phytophthora and Pythium for greenhouse-grown squash and poinsettia, respectively, in comparison with fungicide treatment. For squash, filtration by iron oxide coated media was more effective in reducing the Phytophthora infection, comparing to sand filtration and fungicide application. For poinsettia, sand filtration performed better in controlling

  19. Inhibition of human pathogenic fungi by ethnobotanically selected plant extracts.

    Science.gov (United States)

    Ficker, Christine E; Arnason, J T; Vindas, P S; Alvarez, L P; Akpagana, K; Gbéassor, M; De Souza, C; Smith, M L

    2003-02-01

    In this study, 36 extracts derived from 29 plant species selected using an ethnobotanical approach were tested for antifungal activity against a taxonomically diverse group of 13 human pathogenic fungi. We compared the inhibitory characteristics of these plant extracts with those of the commonly used antifungals, amphotericin B and ketoconazole, and the plant-derived antifungal, berberine. Several plant extracts, notably those from Zingiber officinale (ginger) and Juglans cinerea (butternut), had pronounced antifungal activity against a wide variety of fungi, including strains that were highly resistant to amphotericin B and ketoconazole. Further exploration of Z. officinale as an antifungal is warranted as this species is generally regarded as safe for human consumption. PMID:12588480

  20. Plant-RNA viroid relationship: a complex host pathogen interaction

    Directory of Open Access Journals (Sweden)

    Parisi, O.

    2010-01-01

    Full Text Available Viroids are non encapsidated small RNA plant pathogens unable to produce any protein. They are able to infect dramatically a broad range of plants including herbaceous and tree crops. The ways by which viroids are able to induce diseases are actually unknown. However, recent studies have shown that viroids are able to regulate the gene expression of their hosts, they can modify the host-protein phosphorylation sensibility and they interact with host-protein implicated RNA trafficking and protein phosphorylation. Moreover during their evolution plants have developed a mechanism able to regulate their gene expression and to degrade exogenous RNAs like viroids: the gene silencing. Unfortunately, this pathway seems, now, also highly implicated in the symptoms development. This review describes studies that are realized since a few years to increase the knowledge about the plant-viroid relationship.

  1. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams

    Science.gov (United States)

    Duris, Joseph W.; Reif, Andrew G.; Donna A. Crouse; Isaacs, Natasha M.

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfbO157) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but notCryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfbO157, STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2

  2. Fecal indicators and bacterial pathogens in bottled water from Dhaka, Bangladesh

    Directory of Open Access Journals (Sweden)

    W. Ahmed

    2013-01-01

    Full Text Available Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp. and potential bacterial pathogens (i.e., Aeromonas hydrophil, Pseudomonas aeruginos, Salmonella spp., and Shigella spp.. Among the 16 brands tested, 14 (86%, ten (63% and seven (44% were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%, eight (50%, six (37%, and four (25% brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene, 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene, 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245, Salmonella spp. invA (p = 0.433, Shigella spp. ipaH gene (p = 0.078, and P. aeruginosa ETA (p = 0.059 genes. Our results suggest that microbiological quality of bottled waters sold in Dhaka, Bangladesh is highly variable. To protect public health, stringent quality control is recommended for the bottled water industry in Bangladesh.

  3. Effects of Bacillus amyloliquefaciens FZB42 on lettuce growth and health under pathogen pressure and its impact on the rhizosphere bacterial community.

    Directory of Open Access Journals (Sweden)

    Soumitra Paul Chowdhury

    Full Text Available The soil-borne pathogen Rhizoctonia solani is responsible for crop losses on a wide range of important crops worldwide. The lack of effective control strategies and the increasing demand for organically grown food has stimulated research on biological control. The aim of the present study was to evaluate the rhizosphere competence of the commercially available inoculant Bacillus amyloliquefaciens FZB42 on lettuce growth and health together with its impact on the indigenous rhizosphere bacterial community in field and pot experiments. Results of both experiments demonstrated that FZB42 is able to effectively colonize the rhizosphere (7.45 to 6.61 Log 10 CFU g(-1 root dry mass within the growth period of lettuce in the field. The disease severity (DS of bottom rot on lettuce was significantly reduced from severe symptoms with DS category 5 to slight symptom expression with DS category 3 on average through treatment of young plants with FZB42 before and after planting. The 16S rRNA gene based fingerprinting method terminal restriction fragment length polymorphism (T-RFLP showed that the treatment with FZB42 did not have a major impact on the indigenous rhizosphere bacterial community. However, the bacterial community showed a clear temporal shift. The results also indicated that the pathogen R. solani AG1-IB affects the rhizosphere microbial community after inoculation. Thus, we revealed that the inoculant FZB42 could establish itself successfully in the rhizosphere without showing any durable effect on the rhizosphere bacterial community.

  4. Effects of Bacillus amyloliquefaciens FZB42 on lettuce growth and health under pathogen pressure and its impact on the rhizosphere bacterial community.

    Science.gov (United States)

    Chowdhury, Soumitra Paul; Dietel, Kristin; Rändler, Manuela; Schmid, Michael; Junge, Helmut; Borriss, Rainer; Hartmann, Anton; Grosch, Rita

    2013-01-01

    The soil-borne pathogen Rhizoctonia solani is responsible for crop losses on a wide range of important crops worldwide. The lack of effective control strategies and the increasing demand for organically grown food has stimulated research on biological control. The aim of the present study was to evaluate the rhizosphere competence of the commercially available inoculant Bacillus amyloliquefaciens FZB42 on lettuce growth and health together with its impact on the indigenous rhizosphere bacterial community in field and pot experiments. Results of both experiments demonstrated that FZB42 is able to effectively colonize the rhizosphere (7.45 to 6.61 Log 10 CFU g(-1) root dry mass) within the growth period of lettuce in the field. The disease severity (DS) of bottom rot on lettuce was significantly reduced from severe symptoms with DS category 5 to slight symptom expression with DS category 3 on average through treatment of young plants with FZB42 before and after planting. The 16S rRNA gene based fingerprinting method terminal restriction fragment length polymorphism (T-RFLP) showed that the treatment with FZB42 did not have a major impact on the indigenous rhizosphere bacterial community. However, the bacterial community showed a clear temporal shift. The results also indicated that the pathogen R. solani AG1-IB affects the rhizosphere microbial community after inoculation. Thus, we revealed that the inoculant FZB42 could establish itself successfully in the rhizosphere without showing any durable effect on the rhizosphere bacterial community. PMID:23935892

  5. A bacterial acetyltransferase destroys plant microtubule networks and blocks secretion

    Science.gov (United States)

    The eukaryotic cytoskeleton is essential for structural support and intracellular transport, and is therefore a common target of animal pathogens. However, no phytopathogenic effector has yet been demonstrated to specifically target the plant cytoskeleton. Here we show that the Pseudomonas syringae...

  6. Quorum-sensing blockade as a strategy for enhancing host defences against bacterial pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    Conventional antibiotics target the growth and the basal life processes of bacteria leading to growth arrest and cell death. The selective force that is inherently linked to this mode of action eventually selects out antibiotic-resistant variants. The most obvious alternative to antibiotic...... rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS is...... likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi...

  7. Quorum-Sensing Blockade As A Strategy for Enhancing Host Defences Against Bacterial Pathogens

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2007-01-01

    Conventional antibiotics target the growth and the basal life processes of bacteria leading to growth arrest and cell death. The selective force that is inherently linked to this mode of action eventually selects out antibiotic-resistant variants. The most obvious alternative to antibiotic...... rise to a new 'drug target rush'. Recently, QS has been shown to be involved in the development of tolerance to various antimicrobial treatments and immune modulation. The regulation of virulence via QS confers a strategic advantage over host defences. Consequently, a drug capable of blocking QS is...... likely to increase the susceptibility of the infecting organism to host defences and its clearance from the host. The use of QS signal blockers to attenuate bacterial pathogenicity, rather than bacterial growth, is therefore highly attractive, particularly with respect to the emergence of multi...

  8. Bioinhibition of diarrhogenic Gram-positive bacterial patho-gens by potential indigenous probiotics

    Institute of Scientific and Technical Information of China (English)

    Adenike A.O.Ogunshe

    2008-01-01

    High level infant mortality rates and onset of drug resistance has led into the possible development of indige-nous probiotics as alternative bacteriotherapy in the control of infantile bacterial diarrhoea.This study was to determine the in vitro inhibitory potential of four probiotic candidates obtained from Nigerian indigenous fer-mented foods and beverages and from faecal specimens of healthy infants on infantile Gram-positive diarrhogen-ic bacterial pathogens.Potential probiotic candidates,AAOOL4,L.reuteri AAOOCH1,L.plantarum AAOO25 NN and L.delbrueckii AAOOT20 were assayed for in vitro bactericidal effects on diarrhogenic bacte-rial test strains-Bacillus cereus 25S,B.cereus 32S,B.licheniformis 26S and B.licheniformis 39S.All the test strains inoculated into an industrial infant weaning food already seeded with the probiotic strains were sig-nificantly inhibited within 96 hours. L. acidophilus AAOOL4, L. reuteri AAOOCH1 , L. plantarum AAOO25 NN and L.delbrueckii AAOOT20 had in vitro bactericidal effects on bacteri isolates implicated in in-fantile diarrhoea,indicating the probiotic potential of the candidates.

  9. Glycosaminoglycan binding facilitates entry of a bacterial pathogen into central nervous systems.

    Science.gov (United States)

    Chang, Yung-Chi; Wang, Zhipeng; Flax, Lindsay A; Xu, Ding; Esko, Jeffrey D; Nizet, Victor; Baron, Miriam J

    2011-06-01

    Certain microbes invade brain microvascular endothelial cells (BMECs) to breach the blood-brain barrier (BBB) and establish central nervous system (CNS) infection. Here we use the leading meningitis pathogen group B Streptococcus (GBS) together with insect and mammalian infection models to probe a potential role of glycosaminoglycan (GAG) interactions in the pathogenesis of CNS entry. Site-directed mutagenesis of a GAG-binding domain of the surface GBS alpha C protein impeded GBS penetration of the Drosophila BBB in vivo and diminished GBS adherence to and invasion of human BMECs in vitro. Conversely, genetic impairment of GAG expression in flies or mice reduced GBS dissemination into the brain. These complementary approaches identify a role for bacterial-GAG interactions in the pathogenesis of CNS infection. Our results also highlight how the simpler yet genetically conserved Drosophila GAG pathways can provide a model organism to screen candidate molecules that can interrupt pathogen-GAG interactions for future therapeutic applications. PMID:21731486

  10. Glycosaminoglycan binding facilitates entry of a bacterial pathogen into central nervous systems.

    Directory of Open Access Journals (Sweden)

    Yung-Chi Chang

    2011-06-01

    Full Text Available Certain microbes invade brain microvascular endothelial cells (BMECs to breach the blood-brain barrier (BBB and establish central nervous system (CNS infection. Here we use the leading meningitis pathogen group B Streptococcus (GBS together with insect and mammalian infection models to probe a potential role of glycosaminoglycan (GAG interactions in the pathogenesis of CNS entry. Site-directed mutagenesis of a GAG-binding domain of the surface GBS alpha C protein impeded GBS penetration of the Drosophila BBB in vivo and diminished GBS adherence to and invasion of human BMECs in vitro. Conversely, genetic impairment of GAG expression in flies or mice reduced GBS dissemination into the brain. These complementary approaches identify a role for bacterial-GAG interactions in the pathogenesis of CNS infection. Our results also highlight how the simpler yet genetically conserved Drosophila GAG pathways can provide a model organism to screen candidate molecules that can interrupt pathogen-GAG interactions for future therapeutic applications.

  11. Genomic Epidemiology: Whole-Genome-Sequencing–Powered Surveillance and Outbreak Investigation of Foodborne Bacterial Pathogens

    DEFF Research Database (Denmark)

    Deng, Xiangyu; den Bakker, Henk C.; Hendriksen, Rene S.

    2016-01-01

    As we are approaching the twentieth anniversary of PulseNet, a network of public health and regulatory laboratories that has changed the landscape of foodborne illness surveillance through molecular subtyping, public health microbiology is undergoing another transformation brought about by so......-called next-generation sequencing (NGS) technologies that have made whole-genome sequencing (WGS) of foodborne bacterial pathogens a realistic and superior alternative to traditional subtyping methods. Routine, real-time, and widespread application of WGS in food safety and public health is on the horizon...

  12. COMPARATIVE RESISTANCE OF BACTERIAL FOODBORNE PATHOGENS TO NON-THERMAL TECHNOLOGIES FOR FOOD PRESERVATION

    Directory of Open Access Journals (Sweden)

    Guillermo eCebrián

    2016-05-01

    Full Text Available In this paper the resistance of bacterial foodborne pathogens to manosonication (MS, pulsed electric fields (PEF, high hydrostatic pressure (HHP and UV-light (UV is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could

  13. Comparative Resistance of Bacterial Foodborne Pathogens to Non-thermal Technologies for Food Preservation.

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

    In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEFs), high hydrostatic pressure (HHP), and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni) would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could also be

  14. Comparative Resistance of Bacterial Foodborne Pathogens to Non-thermal Technologies for Food Preservation

    Science.gov (United States)

    Cebrián, Guillermo; Mañas, Pilar; Condón, Santiago

    2016-01-01

    In this paper the resistance of bacterial foodborne pathogens to manosonication (MS), pulsed electric fields (PEFs), high hydrostatic pressure (HHP), and UV-light (UV) is reviewed and compared. The influence of different factors on the resistance of bacterial foodborne pathogens to these technologies is also compared and discussed. Only results obtained under harmonized experimental conditions have been considered. This has allowed us to establish meaningful comparisons and draw significant conclusions. Among the six microorganisms here considered, Staphyloccocus aureus is the most resistant foodborne pathogen to MS and HHP and Listeria monocytogenes to UV. The target microorganism of PEF would change depending on the treatment medium pH. Thus, L. monocytogenes is the most PEF resistant microorganism at neutral pH but Gram-negatives (Escherichia coli, Salmonella spp., Cronobacter sakazakii, Campylobacter jejuni) would display a similar or even higher resistance at acidic pH. It should be noted that, in acidic products, the baroresistance of some E. coli strains would be comparable to that of S. aureus. The factors affecting the resistance of bacterial foodborne pathogens, as well as the magnitude of the effect, varied depending on the technology considered. Inter- and intra-specific differences in microbial resistance to PEF and HHP are much greater than to MS and UV. Similarly, both the pH and aw of the treatment medium highly condition microbial resistance to PEF and HHP but no to MS or UV. Growth phase also drastically affected bacterial HHP resistance. Regarding UV, the optical properties of the medium are, by far, the most influential factor affecting its lethal efficacy. Finally, increasing treatment temperature leads to a significant increase in lethality of the four technologies, what opens the possibility of the development of combined processes including heat. The appearance of sublethally damaged cells following PEF and HHP treatments could also be

  15. Toxicity of nitric oxide and peroxynitrite to bacterial pathogens of fish.

    Science.gov (United States)

    Campos-Pérez, J J; Ellis, A E; Secombes, C J

    2000-11-14

    The inhibitory effect of the nitric oxide (NO) donor S-nitroso-acetyl-penicillamine (SNAP) and the NO and O2- donor 3-morpholino-sydnonimine hydrochloride (SIN-1) was tested in a cell-free assay. Strains of the bacterial fish pathogens Aeromonas salmonicida, Renibacterium salmoninarum and Yersinia ruckeri were exposed to different concentrations of the NO donors for 24 h. The results showed that NO possesses inhibitory properties, while peroxynitrite had no effect. However, when SIN-1 was used in combination with superoxide dismutase (SOD) alone or with catalase, an inhibitory effect comparable to that caused by SNAP was seen. The implications of these results are discussed. PMID:11145451

  16. Scope for using plant viruses to present epitopes from animal pathogens.

    Science.gov (United States)

    Porta; Lomonossoff

    1998-01-01

    Epitope presentation to the immune system for vaccination purposes can be achieved either via an inactivated or attenuated form of a pathogen or via its isolated antigenic sequences. When free, these peptides can adopt a variety of conformations, most of which will not exist in their native environment. Conjugation to carrier proteins restricts mobility of the peptides and increases their immunogenicity. A high local concentration of epitopes boosts the immune response further and can be generated by the use of self-aggregating carriers, such as the capsid proteins of viruses. In this regard plant viruses have in recent years started to make an impact as safer alternatives to the use of bacterial and attenuated animal viruses: the latter both require propagation in costly cell-culture systems where they can undergo reversion towards a virulent form and/or become contaminated by other pathogens. Plant virus-based vectors can be multiplied cheaply and to high yields (exceeding 1 mg/g plant tissue) in host plants. Both helical (tobacco mosaic virus, potato virus X, alfalfa mosaic virus) and icosahedral (cowpea mosaic virus, tomato bushy stunt virus) particles have been used to express a number of animal B-cell epitopes, whose immunogenic properties have been explored to varying degrees. Copyright 1998 John Wiley & Sons, Ltd. PMID:10398492

  17. The Top 10 fungal pathogens in molecular plant pathology.

    Science.gov (United States)

    Dean, Ralph; Van Kan, Jan A L; Pretorius, Zacharias A; Hammond-Kosack, Kim E; Di Pietro, Antonio; Spanu, Pietro D; Rudd, Jason J; Dickman, Marty; Kahmann, Regine; Ellis, Jeff; Foster, Gary D

    2012-05-01

    The aim of this review was to survey all fungal pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate which fungal pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 495 votes from the international community, and resulted in the generation of a Top 10 fungal plant pathogen list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Magnaporthe oryzae; (2) Botrytis cinerea; (3) Puccinia spp.; (4) Fusarium graminearum; (5) Fusarium oxysporum; (6) Blumeria graminis; (7) Mycosphaerella graminicola; (8) Colletotrichum spp.; (9) Ustilago maydis; (10) Melampsora lini, with honourable mentions for fungi just missing out on the Top 10, including Phakopsora pachyrhizi and Rhizoctonia solani. This article presents a short resumé of each fungus in the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant mycology community, as well as laying down a bench-mark. It will be interesting to see in future years how perceptions change and what fungi will comprise any future Top 10. PMID:22471698

  18. RIPEN FRUITS OF INDIAN GINSENG: PHYTO-CHEMICAL AND PHARMACOLOGICAL EXAMINATION AGAINST HUMAN AND PLANT PATHOGENS

    Directory of Open Access Journals (Sweden)

    Premlata Singariya

    2012-05-01

    Full Text Available The ripen fruit extracts of Withania somniferawere evaluated against medically importantbacteria viz.Proteusmerabilis, Klebsiella pnemoniae, Agerobacterium tumefaciens(plant pathogenandone fungi Aspergillus niger.The dried and powdered ripen fruits were successively extracted with a seriesof non polar to polar solvents using soxhlet assembly. The antimicrobial assay was done by both discdiffusion and broth dilution methods. Glacial acetic acid extract of W. somniferashow highest activityagainst A. tumefaciens(plant pathogen and water extract againstK. pnemoniaeto varying degrees in theterms of high inhibition zone and activity index. A. tumefacienswas the most susceptible organism incompare to the other organism. Gentamycin and Ketoconazole, the standard antibacterial and antifungalused was effective against the bacteria and fungi. The extract of W. somniferaalso significantly (P>0.005inhibited the bacterial and fungal growth. The inhibitory effect is very identical in magnitude andcomparable with that of standard antibiotics used.

  19. Plant-Associated Bacterial Degradation of Toxic Organic Compounds in Soil

    Directory of Open Access Journals (Sweden)

    David Dowling

    2009-08-01

    Full Text Available A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial or diffuse (e.g., agricultural contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants and rhizospheric bacteria (bacteria that live on and near the roots of plants, have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review.

  20. Plant-associated bacterial degradation of toxic organic compounds in soil.

    LENUS (Irish Health Repository)

    McGuinness, Martina

    2009-08-01

    A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial) or diffuse (e.g., agricultural) contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants) and rhizospheric bacteria (bacteria that live on and near the roots of plants), have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced) in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review.

  1. A sophisticated network of signaling pathways regulates stomatal defenses to bacterial pathogens.

    Science.gov (United States)

    Arnaud, Dominique; Hwang, Ildoo

    2015-04-01

    Guard cells are specialized cells forming stomatal pores at the leaf surface for gas exchanges between the plant and the atmosphere. Stomata have been shown to play an important role in plant defense as a part of the innate immune response. Plants actively close their stomata upon contact with microbes, thereby preventing pathogen entry into the leaves and the subsequent colonization of host tissues. In this review, we present current knowledge of molecular mechanisms and signaling pathways implicated in stomatal defenses, with particular emphasis on plant-bacteria interactions. Stomatal defense responses begin from the perception of pathogen-associated molecular patterns (PAMPs) and activate a signaling cascade involving the production of secondary messengers such as reactive oxygen species, nitric oxide, and calcium for the regulation of plasma membrane ion channels. The analyses on downstream molecular mechanisms implicated in PAMP-triggered stomatal closure have revealed extensive interplays among the components regulating hormonal signaling pathways. We also discuss the strategies deployed by pathogenic bacteria to counteract stomatal immunity through the example of the phytotoxin coronatine. PMID:25661059

  2. Co-transcriptomic Analysis by RNA Sequencing to Simultaneously Measure Regulated Gene Expression in Host and Bacterial Pathogen

    KAUST Repository

    Ravasi, Timothy

    2016-01-24

    Intramacrophage pathogens subvert antimicrobial defence pathways using various mechanisms, including the targeting of host TLR-mediated transcriptional responses. Conversely, TLR-inducible host defence mechanisms subject intramacrophage pathogens to stress, thus altering pathogen gene expression programs. Important biological insights can thus be gained through the analysis of gene expression changes in both the host and the pathogen during an infection. Traditionally, research methods have involved the use of qPCR, microarrays and/or RNA sequencing to identify transcriptional changes in either the host or the pathogen. Here we describe the application of RNA sequencing using samples obtained from in vitro infection assays to simultaneously quantify both host and bacterial pathogen gene expression changes, as well as general approaches that can be undertaken to interpret the RNA sequencing data that is generated. These methods can be used to provide insights into host TLR-regulated transcriptional responses to microbial challenge, as well as pathogen subversion mechanisms against such responses.

  3. Influence of Tillage and Daily Manure Application on the Survival of Bacterial Pathogens Indicators in Soil and on Radish

    International Nuclear Information System (INIS)

    We measured Escherichia coli, and Enterococcus sp. numbers in soil and on fresh radish (Raphanus sativus L.) at 1, 7, 14, 28, 54, and 84 days after the addition of high and low amounts of solid dairy manure in combination with chisel tillage to a 20 cm depth (deep) or roller tillage to a 10 cm depth (shallow). When the high or low amount of solid dairy manure was added to the soil, E. coli populations in soil were higher in the 54 days following manure addition compared to the control treatment. Dairy manure addition increased Enterococcus sp. in soils compared to the control treatment for the entire 84 days sampling period. At harvest, which was 84 days after application, we did not detect E. coli in radish in rhizosphere soil or on radish roots. Addition of solid dairy manure increased Enterococcus sp. numbers in radish rhizosphere soil and on radish roots. We suggest that fresh animal manure be applied to soil at least 120 days prior to planting to allow die-off of human pathogenic bacteria and reduce the incidence of bacterial adhesion on or bacterial colonization of ready to eat vegetables.

  4. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital, Indonesia

    Institute of Scientific and Technical Information of China (English)

    Maksum Radji; Siti Fauziah; Nurgani Aribinuko

    2011-01-01

    Objective: To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit (ICU) of a tertiary care of Fatmawati Hospital Jakarta Indonesia. Methods: A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods, and their antibiotic susceptibility testing was performed using disk diffusion method. Results: Specimens were collected from 385 patients who were given antimicrobial treatment, of which 249 (64.68%) were cultured positive and 136 (35.32%) were negative. The most predominant isolate was Pseudomonas aeruginosa (P. aeruginosa) (26.5%) followed by Klebsiella pneumoniae (K. pneumoniae) (15.3%) and Staphylococcus epidermidis (14.9%). P. aeruginosa isolates showed high rate of resistance to cephalexin (95.3%), cefotaxime (64.1%), and ceftriaxone (60.9%). Amikacin was the most effective (84.4%) antibiotic against P. aeruginosa followed by imipenem (81.2%), and meropenem (75.0%). K. pneumoniae showed resistance to cephalexin (86.5%), ceftriaxone (75.7%), ceftazidime (73.0%), cefpirome (73.0%) and cefotaxime (67.9%), respectively. Conclusions: Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins, and quinolone antibiotics. Regular surveillance of antibiotic susceptibility patterns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

  5. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    Science.gov (United States)

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship. PMID:25815838

  6. Studies on antimicrobial and antifungal activities of ziziphus mauritiana human clinical bacterial and fungal pathogens

    International Nuclear Information System (INIS)

    The antimicrobial and antifungal activities of crude extracts of Ziziphus mauritiana leaves were investigated against six selected bacterial (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella pneumoniae) and one fungal pathogen (Aspel-gillus niger). The crude extract was further fractionated in butanol, choloroform, n-hexane and methanol. Agar well diffusion and agar dilution assay were employed for determination of zones of inhibition and MICs, respectively, whereas MBC was determined using broth dilution test. The butanol fraction presented encouraging antimicrobial activity (15.0%0.02), while methanol (7.03:1:0.05) and chloroform (7.0%0,05) fractions emerged with significantly low susceptibility. The n-hexane fraction was recorded as almost inactive (0%0) against all bacterial pathogens. Unlike the antibacterial activities, all fractions possessed momentous antifungal activities except the methanol fraction (0%0). The n-hexane fraction showed widest zone of inhibition (11:1:0.05) followed by butanol (8.0%0.02) and chloroform (7.0%0.02). (author)

  7. Defense mechanisms of Solanum tuberosum L. in response to attack by plant-pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    VERA A D POIATTI

    2009-01-01

    Full Text Available The natural resistance of plants to disease is based not only on preformed mechanisms, but also on induced mechanisms. The defense mechanisms present in resistant plants may also be found in susceptible ones. This study attempted to analyze the metabolic alterations in plants of the potato Solanum tuberosum L. cv. Agata that were inoculated with the incompatible plant-pathogenic bacteria X. axonopodis and R. solanacearum, and the compatible bacterium E. carotovora. Levels of total phenolic compounds, including the flavonoid group, and the activities of polyphenol oxidase (PPO and peroxidase (POX were evaluated. Bacteria compatibility was evaluated by means of infiltration of tubers. The defense response was evaluated in the leaves of the potato plants. Leaves were inoculated depending on their number and location on the stem. Multiple-leaf inoculation was carried out on basal, intermediate, and apical leaves, and single inoculations on intermediate leaves. Leaves inoculated with X. axonopodis and with R. solanacearum showed hypersensitive responses within 24 hours post-inoculation, whereas leaves inoculated with E. carotovora showed disease symptoms. Therefore, the R. solanacearum isolate used in the experiments did not exhibit virulence to this potato cultivar. Regardless of the bacterial treatments, the basal leaves showed higher PPO and POX activities and lower levels of total phenolic compounds and flavonoids, compared to the apical leaves. However, basal and intermediate leaves inoculated with R. solanacearum and X. axonopodis showed increases in total phenolic compounds and flavonoid levels. In general, multiple-leaf inoculation showed the highest levels of total phenolics and flavonoids, whereas the single inoculations resulted in the highest increase in PPO activity. The POX activity showed no significant difference between single- and multiple-leaf inoculations. Plants inoculated with E. carotovora showed no significant increase in

  8. The plant pathogen Pseudomonas syringae pv. tomato is genetically monomorphic and under strong selection to evade tomato immunity.

    Directory of Open Access Journals (Sweden)

    Rongman Cai

    2011-08-01

    Full Text Available Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen microevolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of this pathogen. Further analysis with genome-derived markers of 89 world-wide isolates showed that several genotypes exist in North America and in Europe indicating frequent pathogen movement between these world regions. Genome-derived markers and molecular analyses of key pathogen loci important for virulence and motility both suggest ongoing adaptation to the tomato host. A mutational hotspot was found in the type III-secreted effector gene hopM1. These mutations abolish the cell death triggering activity of the full-length protein indicating strong selection for loss of function of this effector, which was previously considered a virulence factor. Two non-synonymous mutations in the flagellin-encoding gene fliC allowed identifying a new microbe associated molecular pattern (MAMP in a region distinct from the known MAMP flg22. Interestingly, the ancestral allele of this MAMP induces a stronger tomato immune response than the derived alleles. The ancestral allele has largely disappeared from today's Pto populations suggesting that flagellin-triggered immunity limits pathogen fitness even in highly virulent pathogens. An additional non-synonymous mutation was identified in flg22 in South American isolates. Therefore, MAMPs are more variable than expected differing even between otherwise almost identical isolates of the same pathogen strain.

  9. Contribution of proteomics to the study of plant pathogenic fungi.

    Science.gov (United States)

    Gonzalez-Fernandez, Raquel; Jorrin-Novo, Jesus V

    2012-01-01

    Phytopathogenic fungi are one of the most damaging plant parasitic organisms, and can cause serious diseases and important yield losses in crops. The study of the biology of these microorganisms and the interaction with their hosts has experienced great advances in recent years due to the development of moderm, holistic and high-throughput -omic techniques, together with the increasing number of genome sequencing projects and the development of mutants and reverse genetics tools. We highlight among these -omic techniques the importance of proteomics, which has become a relevant tool in plant-fungus pathosystem research. Proteomics intends to identify gene products with a key role in pathogenicity and virulence. These studies would help in the search of key protein targets and in the development of agrochemicals, which may open new ways for crop disease diagnosis and protection. In this review, we made an overview on the contribution of proteomics to the knowledge of life cycle, infection mechanisms, and virulence of the plant pathogenic fungi. Data from current, innovative literature, according to both methodological and experimental systems, were summarized and discussed. Specific sections were devoted to the most studied fungal phytopathogens: Botrytis cinerea, Sclerotinia sclerotiorum, and Fusarium graminearum. PMID:22085090

  10. Metabolic pathways of Pseudomonas aeruginosa involved in competition with respiratory bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Marie eBeaume

    2015-04-01

    Full Text Available Background: Chronic airway infection by Pseudomonas aeruginosa considerably contributes to lung tissue destruction and impairment of pulmonary function in cystic-fibrosis (CF patients. Complex interplays between P. aeruginosa and other co-colonizing pathogens including Staphylococcus aureus, Burkholderia spp and Klebsiella pneumoniae may be crucial for pathogenesis and disease progression.Methods: We generated a library of PA14 transposon insertion mutants to identify P. aeruginosa genes required for exploitative and direct competitions with S. aureus, B. cenocepacia, and K. pneumoniae. Results: Whereas wild type PA14 inhibited S. aureus growth, two transposon insertions located in pqsC and carB, resulted in reduced growth inhibition. PqsC is involved in the synthesis of 4-hydroxy-2-alkylquinolines (HAQs, a family of molecules having antibacterial properties, while carB is a key gene in pyrimidine biosynthesis. The carB mutant was also unable to grow in the presence of B. cepacia and K. pneumoniae but not E. coli and S. epidermidis. We further identified a transposon insertion in purF, encoding a key enzyme of purine metabolism. This mutant displayed a severe growth deficiency in the presence of Gram-negative but not of Gram-positive bacteria. We identified a beneficial interaction in a bioA transposon mutant, unable to grow on rich medium. This growth defect could be restored either by addition of biotin or by co-culturing the mutant in the presence of K. pneumoniae or E. coli.Conclusions: Complex interactions take place between the various bacterial species colonizing CF-lungs. This work identified both detrimental and beneficial interactions occurring between P. aeruginosa and three other respiratory pathogens involving several major metabolic pathways. Manipulating these pathways could be used to interfere with bacterial interactions and influence the colonization by respiratory pathogens.

  11. A human pathogenic bacterial infection model using the two-spotted cricket, Gryllus bimaculatus.

    Science.gov (United States)

    Kochi, Yuto; Miyashita, Atsushi; Tsuchiya, Kohsuke; Mitsuyama, Masao; Sekimizu, Kazuhisa; Kaito, Chikara

    2016-08-01

    Invertebrate animal species that can withstand temperatures as high as 37°C, the human body temperature, are limited. In the present study, we utilized the two-spotted cricket, Gryllus bimaculatus, which lives in tropical and subtropical regions, as an animal model of human pathogenic bacterial infection. Injection of Pseudomonas aeruginosa or Staphylococcus aureus into the hemolymph killed crickets. Injected P. aeruginosa or S. aureus proliferated in the hemolymph until the cricket died. The ability of these pathogenic bacteria to kill the crickets was blocked by the administration of antibiotics. S. aureus gene-knockout mutants of virulence factors, including cvfA, agr and srtA, exhibited decreased killing ability compared with the parent strain. The dose at which 50% of crickets were killed by P. aeruginosa or S. aureus was not decreased at 37°C compared with that at 27°C. Injection of Listeria monocytogenes, which upregulates toxin expression at 37°C, killed crickets, and the dose at which 50% of crickets were killed was decreased at 37°C compared with that at 27°C. These findings suggest that the two-spotted cricket is a useful model animal for evaluating the virulence properties of various human pathogenic bacteria at variable temperature including 37°C. PMID:27377894

  12. A Novel Bacterial Pathogen of Biomphalaria glabrata: A Potential Weapon for Schistosomiasis Control?

    Science.gov (United States)

    Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Allienne, Jean François; Portela, Julien; Calvayrac, Christophe; Rognon, Anne; Arancibia, Nathalie; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2015-01-01

    Background Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects. Methodology/Principal findings In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs. Conclusions/Significance This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field. PMID:25719489

  13. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  14. A Catalytic DNA Activated by a Specific Strain of Bacterial Pathogen.

    Science.gov (United States)

    Shen, Zhifa; Wu, Zaisheng; Chang, Dingran; Zhang, Wenqing; Tram, Kha; Lee, Christine; Kim, Peter; Salena, Bruno J; Li, Yingfu

    2016-02-01

    Pathogenic strains of bacteria are known to cause various infectious diseases and there is a growing demand for molecular probes that can selectively recognize them. Here we report a special DNAzyme (catalytic DNA), RFD-CD1, that shows exquisite specificity for a pathogenic strain of Clostridium difficile (C. difficile). RFD-CD1 was derived by an in vitro selection approach where a random-sequence DNA library was allowed to react with an unpurified molecular mixture derived from this strain of C. difficle, coupled with a subtractive selection strategy to eliminate cross-reactivities to unintended C. difficile strains and other bacteria species. RFD-CD1 is activated by a truncated version of TcdC, a transcription factor, that is unique to the targeted strain of C. difficle. Our study demonstrates for the first time that in vitro selection offers an effective approach for deriving functional nucleic acid probes that are capable of achieving strain-specific recognition of bacterial pathogens. PMID:26676768

  15. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff.

    Science.gov (United States)

    Miller, Melissa A; Byrne, Barbara A; Jang, Spencer S; Dodd, Erin M; Dorfmeier, Elene; Harris, Michael D; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A; Miller, Woutrina A

    2010-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  16. Bacterial-Plant-Interactions: Approaches to Unravel the Biological Function of Bacterial Volatiles in the Rhizosphere.

    Science.gov (United States)

    Kai, Marco; Effmert, Uta; Piechulla, Birgit

    2016-01-01

    Rhizobacteria produce an enormous amount of volatile compounds, however, the function of these metabolites is scarcely understood. Investigations evaluating influences on plants performed in various laboratories using individually developed experimental setups revealed different and often contradictory results, e.g., ranging from a significant plant growth promotion to a dramatic suppression of plant development. In addition to these discrepancies, these test systems neglected properties and complexity of the rhizosphere. Therefore, to pursue further investigations of the role of bacterial volatiles in this underground habitat, the applied methods have to simulate its natural characteristics as much as possible. In this review, we will describe and discuss pros and cons of currently used bioassays, give insights into rhizosphere characteristics, and suggest improvements for test systems that would consider in natura conditions and would allow gaining further knowledge of the potential function and significance of rhizobacterial volatiles in plant life. PMID:26903987

  17. Essential roles for platelets during neutrophil-dependent or lymphocyte-mediated defense against bacterial pathogens.

    Science.gov (United States)

    Wang, Zheng; Zhao, Qi; Zhang, Dongxia; Sun, Chengming; Bao, Cuixia; Yi, Maoli; Xing, Li; Luo, Deyan

    2016-09-01

    Emerging evidence from animal models suggests that platelets may participate in a wide variety of processes including the immune response against infection. More than 200 whole blood samples from patients and healthy controls were run in the System XE-5000 analyzer, and plasma fractions were separated for the following tests by ELISA, Luminex and light scattering. We describe two mechanisms by which platelets may contribute to immune function against various bacterial pathogens based on increased mean platelet volume in gram-positive bacterial infections and increased platelet counts in gram-negative bacterial infections. Gram-negative bacteria activate platelets to recruit neutrophils, which participate in the immune response against infection. During this process, fractalkine, macrophage inflammatory protein-1β, interleukin-17A, tumor necrosis factor-α and platelet-activating factor were higher in patients infected with Escherichia coli; additionally, giant platelets were observed under the microscope. Meanwhile, we found that platelets played a different role in gram-positive bacterial infections. Specifically, they could actively adhere to gram-positive bacteria in circulation and transfer them to immune sites to promote antibacterial lymphocyte expansion. During this process, complement C3 and factor XI were more highly expressed in patients infected with Staphylococcus aureus; additionally, we detected more small platelets under the microscope. Platelets participate in the immune response against both gram-negative and gram-positive bacteria, although the mechanisms differ. These results will help us understand the complex roles of platelets during infections, and direct our use of antibiotics based on clinical platelet data. PMID:26588444

  18. Microbial pathogens trigger host DNA double-strand breaks whose abundance is reduced by plant defense responses.

    Directory of Open Access Journals (Sweden)

    Junqi Song

    2014-04-01

    Full Text Available Immune responses and DNA damage repair are two fundamental processes that have been characterized extensively, but the links between them remain largely unknown. We report that multiple bacterial, fungal and oomycete plant pathogen species induce double-strand breaks (DSBs in host plant DNA. DNA damage detected by histone γ-H2AX abundance or DNA comet assays arose hours before the disease-associated necrosis caused by virulent Pseudomonas syringae pv. tomato. Necrosis-inducing paraquat did not cause detectable DSBs at similar stages after application. Non-pathogenic E. coli and Pseudomonas fluorescens bacteria also did not induce DSBs. Elevation of reactive oxygen species (ROS is common during plant immune responses, ROS are known DNA damaging agents, and the infection-induced host ROS burst has been implicated as a cause of host DNA damage in animal studies. However, we found that DSB formation in Arabidopsis in response to P. syringae infection still occurs in the absence of the infection-associated oxidative burst mediated by AtrbohD and AtrbohF. Plant MAMP receptor stimulation or application of defense-activating salicylic acid or jasmonic acid failed to induce a detectable level of DSBs in the absence of introduced pathogens, further suggesting that pathogen activities beyond host defense activation cause infection-induced DNA damage. The abundance of infection-induced DSBs was reduced by salicylic acid and NPR1-mediated defenses, and by certain R gene-mediated defenses. Infection-induced formation of γ-H2AX still occurred in Arabidopsis atr/atm double mutants, suggesting the presence of an alternative mediator of pathogen-induced H2AX phosphorylation. In summary, pathogenic microorganisms can induce plant DNA damage. Plant defense mechanisms help to suppress rather than promote this damage, thereby contributing to the maintenance of genome integrity in somatic tissues.

  19. Spatiotemporal colonization of Xyllela fastidiosa in its vector supports two types of egestion in the inoculation mechanism of foregut-borne plant pathogens

    Science.gov (United States)

    The bacterial agent that causes Pierce’s disease of grapevine, Xylella fastidiosa, is the only known arthropod-transmitted prokaryotic plant pathogen that does not circulate in the vector’s hemolymph. Instead, bacteria are foregut-borne and semi-persistent, i.e. bacteria colonize cuticular surface...

  20. Antimicrobial peptide melittin against Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen in rice.

    Science.gov (United States)

    Shi, Wei; Li, Caiyun; Li, Man; Zong, Xicui; Han, Dongju; Chen, Yuqing

    2016-06-01

    Xanthomonas oryzae pv. oryzae is a destructive bacterial disease of rice, and the development of an environmentally safe bactericide is urgently needed. Antimicrobial peptides, as antibacterial sources, may play important roles in bactericide development. In the present study, we found that the antimicrobial peptide melittin had the desired antibacterial activity against X. oryzae pv. oryzae. The antibacterial mechanism was investigated by examining its effects on cell membranes, energy metabolism, and nucleic acid, and protein synthesis. The antibacterial effects arose from its ability to interact with the bacterial cell wall and disrupt the cytoplasmic membrane by making holes and channels, resulting in the leakage of the cytoplasmic content. Additionally, melittin is able to permeabilize bacterial membranes and reach the cytoplasm, indicating that there are multiple mechanisms of antimicrobial action. DNA/RNA binding assay suggests that melittin may inhibit macromolecular biosynthesis by binding intracellular targets, such as DNA or RNA, and that those two modes eventually lead to bacterial cell death. Melittin can inhibit X. oryzae pv. oryzae from spreading, alleviating the disease symptoms, which indicated that melittin may have potential applications in plant protection. PMID:26948237

  1. Anti-bacterial effect of Mentha spicata L. essential oil on eight standard species of gastrointestinal pathogens

    OpenAIRE

    Majid Zare Bidaki; Mina Arab; Mohtarame Khazaei; Ehsan Afkar

    2014-01-01

    Background and Aim: Nowadays resistance to antibiotics and their side effects has emerged as a worldwide problem. As a result, tend to use anti-bacterial compounds of plant origin has been increased. Mint plant scientifically called Mentha spicata L. is one of the plants which has many medicinal uses and its antibacterial effects is a matter of debate. We aimed to study antibacterial effects of Mentha spicata L essential oil on 8 standard bacterial species including Escherichia coli, Bacillus...

  2. Internalization of bacterial pathogens in tomatoes and their control by selected chemicals.

    Science.gov (United States)

    Ibarra-Sánchez, L S; Alvarado-Casillas, S; Rodríguez-García, M O; Martínez-Gonzáles, N E; Castillo, A

    2004-07-01

    The effect of different washing or sanitizing agents was compared for preventing or reducing surface and internal contamination of tomatoes by Salmonella Typhimurium and Escherichia coli O157:H7. The tomatoes were inoculated by dipping them in a bacterial suspension containing approximately 6.0 log CFU/ml of each pathogen and then rinsing them with tap water, hypochlorite solution (250 mg/liter), or lactic acid solution (2%, wt/vol). All treatments were applied by dipping or spraying, and solutions were applied at 5, 25, 35, and 55 degrees C. With the exception of the lactic acid dip at 5 degrees C, all treatments reduced both pathogens on the surfaces of the tomatoes by at least 2.9 cycles. No significantly different results were obtained (P > 0.05) with the dipping and spraying techniques. For internalized pathogens, the mean counts for tomatoes treated with water alone or with chlorine ranged from 0.8 to 2.1 log CFU/g. In contrast, after lactic acid spray treatment, all core samples of tomatoes tested negative for Salmonella Typhimurium and, except for one sample with a low but detectable count, all samples tested negative for E. coli O157:H7 with a plate count method. When the absence of pathogens was verified by an enrichment method, Salmonella was not recovered from any samples, whereas two of four samples tested positive for E. coli O157:H7 even though the counts were negative. Few cells of internalized pathogens were able to survive in the center of the tomato during storage at room temperature (25 to 28 degrees C). The average superficial pH of tomatoes treated with tap water, chlorine, or lactic acid was 4.9 to 5.2, 4.1 to 4.3, and 2.5, respectively (P lactic acid sprays may be a more effective alternative for decontaminating tomato surfaces. The use of warm (55 degrees C) sprays could reduce pathogen internalization during washing. PMID:15270485

  3. Pectin and Xyloglucan Influence the Attachment of Salmonella enterica and Listeria monocytogenes to Bacterial Cellulose-Derived Plant Cell Wall Models.

    Science.gov (United States)

    Tan, Michelle S F; Rahman, Sadequr; Dykes, Gary A

    2016-01-01

    Minimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of three Salmonella enterica strains (Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028, and Salmonella enterica subsp. indica M4) and Listeria monocytogenes ATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations of S. Typhimurium ATCC 14028 and L. monocytogenes ATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of the Salmonella strains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of how Salmonella enterica and Listeria monocytogenes attach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces. PMID:26567310

  4. Bacterial pathogens implicated in causing urinary tract infection (uti and their antimicrobial susceptibility pattern in Ethiopia

    Directory of Open Access Journals (Sweden)

    Theodros Getachew

    2010-01-01

    Full Text Available Introduction: Urinary Tract Infection (UTI is one of the most common infectious disease ranking next to upper respiratory tract infection is the cause of morbidity and mortality in human. They are mostly caused by bacteria. However, studies conducted in Ethiopia are few and are not extensive. Therefore, studying bacterial pathogens causing UTI and their drug susceptibility patterns is of a highest priority. Material & Methods: A total of 3228 urine samples were collected from 2004 to 2009. Fresh midstream urine samples were aseptically collected in sterile containers. Each sample was cultured onto 5% sheep blood agar and CLED agar plates using a calibrated loop, delivering 1ul of the sample. This was incubated at 37° C aerobically overnight. Bacterial isolates were identified using standard biochemical tests and antimicrobial susceptibility pattern was determined using the Kirby ¿ Bauer¿s disk diffusion method followed CLSI guidelines. Result & discussion: From a total of 3228 urine samples significant bacterial growth was obtained from 651 samples. The gram positive and negative bacteria accounted 17.7 % and 80.2% respectively, the rest 2.2 % are yeasts. The majority 475(72.9 of the isolates were from women while the remaining 176 (27.1 were from men. A wide spectrum of uropathogens was isolated, of which 359 (55.1 % were Escherichia coli, 107 (16.4 % Klebsiella species, 66 (10.1 % streptococcus species, 49(7.5% staphylococcus species, 14 (2.2 % citrobacter species, 14 (2.2 % candida species, 13 (2 % enterobacter species, 11 (1.7 % pseudomonas and the rest 2.8% are 5 proteus species, 5 salmonella species, 4 acinetobacter species and 4 M. morganii. Resistance rate to Gram-negative bacilli were 96 % to amoxicilline-clavulanic acid, 66.9 % to tetracycline, 61.4 % to ampicillin, 64.7 % to trimethoprimsulfamethoxazole, 37.6 % to chloramphenicol, 34 % to norfloxacine and 22.4 % to ceftriaxone. Among Gram-positive, 45.1 % were resistant to

  5. Bacterial secondary production on vascular plant detritus: relationships to detritus composition and degradation rate.

    OpenAIRE

    Moran, M.A. (María Asunción); Hodson, R E

    1989-01-01

    Bacterial production at the expense of vascular plant detritus was measured for three emergent plant species (Juncus effusus, Panicum hemitomon, and Typha latifolia) degrading in the littoral zone of a thermally impacted lake. Bacterial secondary production, measured as tritiated thymidine incorporation into DNA, ranged from 0.01 to 0.81 microgram of bacterial C mg of detritus-1 day-1. The three plant species differed with respect to the amount of bacterial productivity they supported per mil...

  6. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

    OpenAIRE

    Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.

    2009-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile...

  7. Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

    Science.gov (United States)

    Olapade, Ola A; Pung, Kayleigh

    2012-06-01

    Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus. PMID:22625420

  8. Genomic Epidemiology: Whole-Genome-Sequencing-Powered Surveillance and Outbreak Investigation of Foodborne Bacterial Pathogens.

    Science.gov (United States)

    Deng, Xiangyu; den Bakker, Henk C; Hendriksen, Rene S

    2016-01-01

    As we are approaching the twentieth anniversary of PulseNet, a network of public health and regulatory laboratories that has changed the landscape of foodborne illness surveillance through molecular subtyping, public health microbiology is undergoing another transformation brought about by so-called next-generation sequencing (NGS) technologies that have made whole-genome sequencing (WGS) of foodborne bacterial pathogens a realistic and superior alternative to traditional subtyping methods. Routine, real-time, and widespread application of WGS in food safety and public health is on the horizon. Technological, operational, and policy challenges are still present and being addressed by an international and multidisciplinary community of researchers, public health practitioners, and other stakeholders. PMID:26772415

  9. Artificial bacterial biomimetic nanoparticles synergize pathogen-associated molecular patterns for vaccine efficacy.

    Science.gov (United States)

    Siefert, Alyssa L; Caplan, Michael J; Fahmy, Tarek M

    2016-08-01

    Antigen-presenting cells (APCs) sense microorganisms via pathogen-associated molecular patterns (PAMPs) by both extra- and intracellular Toll-like Receptors (TLRs), initiating immune responses against invading pathogens. Bacterial PAMPs include extracellular lipopolysaccharides and intracellular unmethylated CpG-rich oligodeoxynucleotides (CpG). We hypothesized that a biomimetic approach involving antigen-loaded nanoparticles (NP) displaying Monophosphoryl Lipid A (MPLA) and encapsulating CpG may function as an effective "artificial bacterial" biomimetic vaccine platform. This hypothesis was tested in vitro and in vivo using NP assembled from biodegradable poly(lactic-co-glycolic acid) (PLGA) polymer, surface-modified with MPLA, and loaded with CpG and model antigen Ovalbumin (OVA). First, CpG potency, characterized by cytokine profiles, titers, and antigen-specific T cell responses, was enhanced when CpG was encapsulated in NP compared to equivalent concentrations of surface-presented CpG, highlighting the importance of biomimetic presentation of PAMPs. Second, NP synergized surface-bound MPLA with encapsulated CpG in vitro and in vivo, inducing greater pro-inflammatory, antigen-specific T helper 1 (Th1)-skewed cellular and antibody-mediated responses compared to single PAMPs or soluble PAMP combinations. Importantly, NP co-presentation of CpG and MPLA was critical for CD8(+) T cell responses, as vaccination with a mixture of NP presenting either CpG or MPLA failed to induce cellular immunity. This work demonstrates a rational methodology for combining TLR ligands in a context-dependent manner for synergistic nanoparticulate vaccines. PMID:27162077

  10. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital,Indonesia

    Institute of Scientific and Technical Information of China (English)

    Maksum; Radji; Siti; Fauziah; Nurgani; Aribinuko

    2011-01-01

    Objective:To evaluate the sensitivity pattern of bacterial pathogens in the intensive care unit(ICU) of a tertiary care of Falmawati Hospital Jakarta Indonesia.Methods:A cross sectional retrospective study of bacterial pathogen was carried out on a total of 722 patients that were admitted to the ICU of Fatmawati Hospital Jakarta Indonesia during January 2009 to March 2010. All bacteria were identified by standard microbiologic methods,and(heir antibiotic susceptibility testing was performed using disk diffusion method.Results:Specimens were collected from 385 patients who were given antimicrobial treatment,of which 249(64.68%) were cultured positive and 136(35.32%) were negative.The most predominant isolate was Pseudomonas aeruginosa(P.aeruginosa)(26.5%) followed by Klebsiella pneumoniae(K.pneumoniae)(15.3%) and Staphylococcus epidermidis(14.9%).P.aeruginosa isolates showed high rate of resistance to cephalexin(95.3%),cefotaxime(64.1%),and ceftriaxone(60.9%).Amikacin was the most effective(84.4%) antibiotic against P.aeruginosa followed by imipenem(81.2%),and meropenem(75.0%).K.pneumoniae showed resistance to cephalexin(86.5%),ceftriaxone(75.7%),ceftazidime(73.0%),cefpirome(73.0%) and cefotaxime(67.9%),respectively.Conclusions:Most bacteria isolated from ICU of Fatmawati Hospital Jakarta Indonesia were resistant to the third generation of cephalosporins,and quinolone antibiotics.Regular surveillance of antibiotic susceptibility pallerns is very important for setting orders to guide the clinician in choosing empirical or directed therapy of infected patients.

  11. Bacterial rRNA-Targeted Reverse Transcription-PCR Used To Identify Pathogens Responsible for Fever with Neutropenia▿

    OpenAIRE

    Sakaguchi, Sachi; Saito, Masahiro; Tsuji, Hirokazu; Asahara, Takashi; Takata, Oto; Fujimura, Junya; NAGATA, Satoru; Nomoto, Koji; Shimizu, Toshiaki

    2010-01-01

    The purpose of this study was to evaluate the clinical utility of bacterial rRNA-targeted reverse transcription-quantitative PCR (BrRNA RT-qPCR) assays for identifying the bacterial pathogens that cause fever with neutropenia in pediatric cancer patients, by comparing the bacterial detection rate of this technique with that of blood culture. One milliliter of blood was collected from pediatric patients who developed fever with neutropenia following cancer chemotherapy. BrRNA RT-qPCR was perfo...

  12. Localization of adhesins on the surface of a pathogenic bacterial envelope through atomic force microscopy

    Science.gov (United States)

    Arnal, L.; Longo, G.; Stupar, P.; Castez, M. F.; Cattelan, N.; Salvarezza, R. C.; Yantorno, O. M.; Kasas, S.; Vela, M. E.

    2015-10-01

    Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract infection, an important protein participating in the adhesion process is a 220 kDa adhesin named filamentous haemagglutinin (FHA), an outer membrane and also secreted protein that contains recognition domains to adhere to ciliated respiratory epithelial cells and macrophages. In this work, we obtained information on the cell-surface localization and distribution of the B. pertussis adhesin FHA using an antibody-functionalized AFM tip. Through the analysis of specific molecular recognition events we built a map of the spatial distribution of the adhesin which revealed a non-homogeneous pattern. Moreover, our experiments showed a force induced reorganization of the adhesin on the surface of the cells, which could explain a reinforced adhesive response under external forces. This single-molecule information contributes to the understanding of basic molecular mechanisms used by bacterial pathogens to cause infectious disease and to gain insights into the structural features by which adhesins can act as force sensors under mechanical shear conditions.Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract

  13. Transcriptional responses of resistant and susceptible fish clones to the bacterial pathogen Flavobacterium psychrophilum.

    Directory of Open Access Journals (Sweden)

    Christelle Langevin

    Full Text Available Flavobacterium psychrophilum is a bacterial species that represents one of the most important pathogens for aquaculture worldwide, especially for salmonids. To gain insights into the genetic basis of the natural resistance to F. psychrophilum, we selected homozygous clones of rainbow trout with contrasted susceptibility to the infection. We compared the transcriptional response to the bacteria in the pronephros of a susceptible and a resistant line by micro-array analysis five days after infection. While the basal transcriptome of healthy fish was significantly different in the resistant and susceptible lines, the transcriptome modifications induced by the bacteria involved essentially the same genes and pathways. The response to F. psychrophilum involved antimicrobial peptides, complement, and a number of enzymes and chemokines. The matrix metalloproteases mmp9 and mmp13 were among the most highly induced genes in both genetic backgrounds. Key genes of both pro- and anti-inflammatory response such as IL1 and IL10, were up-regulated with a greater magnitude in susceptible animals where the bacterial load was also much higher. While higher resistance to F. psychrophilum does not seem to be based on extensive differences in the orientation of the immune response, several genes including complement C3 showed stronger induction in the resistant fish. They may be important for the variation of susceptibility to the infection.

  14. Hyperglycemia Impairs Neutrophil-Mediated Bacterial Clearance in Mice Infected with the Lyme Disease Pathogen

    Science.gov (United States)

    Javid, Ashkan; Zlotnikov, Nataliya; Pětrošová, Helena; Tang, Tian Tian; Zhang, Yang; Bansal, Anil K.; Ebady, Rhodaba; Parikh, Maitry; Ahmed, Mijhgan; Sun, Chunxiang; Newbigging, Susan; Kim, Yae Ram; Santana Sosa, Marianna; Glogauer, Michael

    2016-01-01

    Insulin-insufficient type 1 diabetes is associated with attenuated bactericidal function of neutrophils, which are key mediators of innate immune responses to microbes as well as pathological inflammatory processes. Neutrophils are central to immune responses to the Lyme pathogen Borrelia burgdorferi. The effect of hyperglycemia on host susceptibility to and outcomes of B. burgdorferi infection has not been examined. The present study investigated the impact of sustained obesity-independent hyperglycemia in mice on bacterial clearance, inflammatory pathology and neutrophil responses to B. burgdorferi. Hyperglycemia was associated with reduced arthritis incidence but more widespread tissue colonization and reduced clearance of bacterial DNA in multiple tissues including brain, heart, liver, lung and knee joint. B. burgdorferi uptake and killing were impaired in neutrophils isolated from hyperglycemic mice. Thus, attenuated neutrophil function in insulin-insufficient hyperglycemia was associated with reduced B. burgdorferi clearance in target organs. These data suggest that investigating the effects of comorbid conditions such as diabetes on outcomes of B. burgdorferi infections in humans may be warranted. PMID:27340827

  15. Hyperglycemia Impairs Neutrophil-Mediated Bacterial Clearance in Mice Infected with the Lyme Disease Pathogen.

    Directory of Open Access Journals (Sweden)

    Ashkan Javid

    Full Text Available Insulin-insufficient type 1 diabetes is associated with attenuated bactericidal function of neutrophils, which are key mediators of innate immune responses to microbes as well as pathological inflammatory processes. Neutrophils are central to immune responses to the Lyme pathogen Borrelia burgdorferi. The effect of hyperglycemia on host susceptibility to and outcomes of B. burgdorferi infection has not been examined. The present study investigated the impact of sustained obesity-independent hyperglycemia in mice on bacterial clearance, inflammatory pathology and neutrophil responses to B. burgdorferi. Hyperglycemia was associated with reduced arthritis incidence but more widespread tissue colonization and reduced clearance of bacterial DNA in multiple tissues including brain, heart, liver, lung and knee joint. B. burgdorferi uptake and killing were impaired in neutrophils isolated from hyperglycemic mice. Thus, attenuated neutrophil function in insulin-insufficient hyperglycemia was associated with reduced B. burgdorferi clearance in target organs. These data suggest that investigating the effects of comorbid conditions such as diabetes on outcomes of B. burgdorferi infections in humans may be warranted.

  16. Lytic bacteriophages in Veterinary Medicine: a therapeutic option against bacterial pathogens?

    Directory of Open Access Journals (Sweden)

    C Borie

    2014-01-01

    Full Text Available The high prevalence of certain bacterial diseases in animals and their economic impact at the productive and public health levels, have directed attention towards the search for new methods of control and prevention, alternative or complementary, that aim to mitigate their adverse effects. This scenario is further complicated by the permanent and rising presence of pathogenic bacteria that are resistant to many antibiotics, limiting the choice of control strategies. In the continuous search for new therapies, there is a renewed interest on the application of bacteriophages, viruses that kill bacteria, as potential antimicrobial agents. Phage therapy in animal production, pets and experimental models of human infection have been discussed in veterinary medicine for 3 decades, with encouraging results in terms of reducing mortality, the severity of the clinical state and bacterial counts at tissue level. These benefits have been achieved thanks to increased knowledge of the biology of phages, better technology that allows their purification and their inherent advantages in terms of their safety for animals. Currently, phage research continues to open new horizons for both the medical industry and the food industry, considering the use of phages in the stages of "farm to fork", with promising results if used as an intervention in animals since their arrival to the slaughter house.

  17. Bacterial pathogen gene regulation: a DNA-structure-centred view of a protein-dominated domain.

    Science.gov (United States)

    Dorman, Charles J; Colgan, Aoife; Dorman, Matthew J

    2016-07-01

    The mechanisms used by bacterial pathogens to regulate the expression of their genes, especially their virulence genes, have been the subject of intense investigation for several decades. Whole genome sequencing projects, together with more targeted studies, have identified hundreds of DNA-binding proteins that contribute to the patterns of gene expression observed during infection as well as providing important insights into the nature of the gene products whose expression is being controlled by these proteins. Themes that have emerged include the importance of horizontal gene transfer to the evolution of pathogens, the need to impose regulatory discipline upon these imported genes and the important roles played by factors normally associated with the organization of genome architecture as regulatory principles in the control of virulence gene expression. Among these architectural elements is the structure of DNA itself, its variable nature at a topological rather than just at a base-sequence level and its ability to play an active (as well as a passive) part in the gene regulation process. PMID:27252403

  18. Caenorhabditis elegans bacterial pathogen resistant bus-4 mutants produce altered mucins.

    Directory of Open Access Journals (Sweden)

    Lisa M Parsons

    Full Text Available Caenorabditis elegans bus-4 glycosyltransferase mutants are resistant to infection by Microbacterium nematophilum, Yersinia pestis and Yersinia pseudotuberculosis and have altered susceptibility to two Leucobacter species Verde1 and Verde2. Our objective in this study was to define the glycosylation changes leading to this phenotype to better understand how these changes lead to pathogen resistance. We performed MALDI-TOF MS, tandem MS and GC/MS experiments to reveal fine structural detail for the bus-4 N- and O-glycan pools. We observed dramatic changes in O-glycans and moderate ones in N-glycan pools compared to the parent strain. Ce core-I glycans, the nematode's mucin glycan equivalent, were doubled in abundance, halved in charge and bore shifts in terminal substitutions. The fucosyl O-glycans, Ce core-II and neutral fucosyl forms, were also increased in abundance as were fucosyl N-glycans. Quantitative expression analysis revealed that two mucins, let-653 and osm-8, were upregulated nearly 40 fold and also revealed was a dramatic increase in GDP-Man 4,6 dehydratease expression. We performed detailed lectin binding studies that showed changes in glycoconjugates in the surface coat, cuticle surface and intestine. The combined changes in cell surface glycoconjugate distribution, increased abundance and altered properties of mucin provide an environment where likely the above pathogens are not exposed to normal glycoconjugate dependent cues leading to barriers to these bacterial infections.

  19. The many forms of a pleomorphic bacterial pathogen – The developmental network of Legionella pneumophila

    Directory of Open Access Journals (Sweden)

    Peter eRobertson

    2014-12-01

    Full Text Available Legionella pneumophila is a natural intracellular bacterial parasite of free-living freshwater protozoa and an accidental human pathogen that causes Legionnaires’ disease. L. pneumophila differentiates, and does it in style. Recent experimental data on L. pneumophila’s differentiation point at the existence of a complex network that involves many developmental forms. We intend readers to: (i understand the biological relevance of L. pneumophila’s forms found in freshwater and their potential to transmit Legionnaires’ disease, and (ii learn that the common depiction of L. pneumophila’s differentiation as a biphasic developmental cycle that alternates between a replicative and a transmissive form is but an oversimplification of the actual process. Our specific objectives are to provide updates on the molecular factors that regulate L. pneumophila’s differentiation (section 2, and describe the developmental network of L. pneumophila (section 3, which for clarity’s sake we have dissected into five separate developmental cycles. Finally, since each developmental form seems to contribute differently to the human pathogenic process and the transmission of Legionnaires’ disease, readers are presented with a challenge to develop novel methods to detect the various L. pneumophila forms present in water (section 4, as a means to improve our assessment of risk and more effectively prevent legionellosis outbreaks.

  20. Viral and bacterial pathogens identification in children hospitalised for severe pneumonia and parapneumonic empyema

    Directory of Open Access Journals (Sweden)

    Jean-Noël Telles

    2012-05-01

    Full Text Available Pneumonia is caused by respiratory bacteria and/or viruses. Little is known if co-infections are an aggravating factor in hospitalised children with severe pneumonia. We studied the impact of respiratory pathogens on the severity of pneumonia. Between 2007 and 2009, 52 children hospitalised with a well-documented diagnosis of communityacquired pneumonia (CAP, with or without parapneumonic empyema (PPE, were enrolled in the study. The patients were classified into 2 groups: CAP + PPE (n = 28 and CAP (n = 24. The identification of respiratory viruses and bacteria in nasopharyngeal aspirates and pleural effusion samples were performed using conventional bacterial techniques and molecular assays. Using real-time multiplex PCR and antigen detection, Streptococcus pneumoniae was the main agent identified in 76% of the cases by molecular tests and BinaxNOW® in pleural fluid. A total of 8% of pleural fluid samples remained undiagnosed. In nasopharyngeal aspirates, rhinovirus, parainfluenza viruses, human metapneumovirus, and respiratory syncytial virus were detected in both CAP and CAP + PPE populations; however, the percentage of viral co-detection was significantly higher in nasopharyngeal aspirates from CAP + PPE patients (35% compared with CAP patients (5%. In conclusion, viral co-detection was observed mainly in patients with more severe pneumonia. Molecular biology assays improved the pathogens detection in pneumonia and confirmed the S. pneumoniae detection by BinaxNOW® in pleural effusion samples. Interestingly, the main S. pneumoniae serotypes found in PPE are not the ones targeted by the heptavalent pneumococcal conjugate vaccine.

  1. A single natural nucleotide mutation alters bacterial pathogen host-tropism

    Science.gov (United States)

    Ward, Melissa J.; Selva, Laura; Guinane, Caitriona M.; González-Muñoz, Beatriz M.; Tristan, Anne; Foster, Simon J; Fitzgerald, J. Ross; Penadés, José R.

    2015-01-01

    The capacity of microbial pathogens to alter their host-tropism leading to epidemics in distinct host-species populations is a global public and veterinary health concern. In order to investigate the molecular basis of a bacterial host-switching event in a tractable host-species, we traced the evolutionary trajectory of the common rabbit clone of Staphylococcus aureus. We report that it evolved through a likely human-to-rabbit host jump over 40 years ago, and that only a single natural nucleotide mutation was required and sufficient to convert a human-specific S. aureus strain into one which could infect rabbits. Related mutations were identified at the same locus in other rabbit strains of distinct clonal origin, consistent with convergent evolution. This first report of a single mutation that was sufficient to alter the host-tropism of a micro-organism during its evolution highlights the capacity of some pathogens to readily expand into novel host-species populations. PMID:25685890

  2. Determination of Contamination Profiles of Human Bacterial Pathogens in Shrimp Obtained from Java, Indonesia

    International Nuclear Information System (INIS)

    Shrimp continues to be an important export commodity for Indonesia and contributed significantly to the country’s revenue. However, shrimp exports have been frequently rejected by importing countries due to filth, Salmonella and insanitary conditions. This study was conducted to evaluate the profiles of bacterial contamination of ocean and aquaculture shrimp obtained from the area of West, Central and East Java; frozen shrimp and shrimp during industry production of frozen shrimp. The study indicated that both ocean and aquaculture shrimp obtained from the study area were heavily contaminated. On the average, shrimp obtained from West Java were more contaminated than those obtained from East and Central Java. The total bacterial counts were generally higher in ocean shrimp than those of aquaculture ones. Salmonella was present in two of 32 samples of ocean shrimp and in four of 32 samples of aquaculture shrimp obtained from the study area. Vibrio cholerae was not detected in shrimp from West Java, but was found in three out of 16 samples obtained from East and Central Java. V. parahaemolyticus was frequently identified in aquaculture shrimp but absent in fresh ocean shrimp. Studies on shrimp collected from six sampling points during frozen shrimp production revealed that processing will reduce the number of total bacterial, E. coli, and Staphylococal counts. However, the processing did not effectively reduce the incidence of Salmonella or V. parahaemolyticus when the raw material has been contaminated with the pathogens. Sizing and grading as well as arrangement of shrimp before freezing were considered as the critical points where bacteria should be controlled to inhibit growth and cross contamination with bacteria such as Listeria. Implementation of Good Agricultural Practices in production of raw shrimp as well as Hazard Analysis Critical Control Point at the line processing are expected to improve the quality of fresh and frozen shrimp. (author)

  3. Detection of Peroxynitrite in Plants Exposed to Bacterial Infection.

    Science.gov (United States)

    Bellin, Diana; Delledonne, Massimo; Vandelle, Elodie

    2016-01-01

    Peroxynitrite is a highly reactive derivative of nitric oxide (NO) which is gaining attention in the plant biology community because it may play a role in NO signaling during biotic stress. Peroxynitrite can react with many different biomolecules, but its ability to nitrate the tyrosine residues of proteins is particularly important because this may regulate defense signaling in response to pathogens. The analysis of peroxynitrite levels in the context of its proposed defense role requires an accurate and specific detection method. Here, we describe a photometric assay using the fluorescent dye Hong Kong Green 2 as a specific and quantitative probe for peroxynitrite in Arabidopsis thaliana plants challenged with an avirulent strain of Pseudomonas syringae pv. tomato. This protocol includes the preparation of plant samples, the assay procedure, the measurement of peroxynitrite-specific fluorescence, and data presentation. PMID:27094421

  4. Identification of a bacterial pathogen associated with Porites white patch syndrome in the Western Indian Ocean.

    Science.gov (United States)

    Séré, Mathieu G; Tortosa, Pablo; Chabanet, Pascale; Quod, Jean-Pascal; Sweet, Michael J; Schleyer, Michael H

    2015-09-01

    Porites white patch syndrome (PWPS) is a coral disease recently described in the Western Indian Ocean. This study aimed to isolate and identify potential pathogens associated with PWPS utilizing both culture and nonculture screening techniques and inoculation trials. A total of 14 bacterial strains (those dominant in disease lesions, absent or rare in healthy tissues and considered potential pathogens in a previous study) were cultured and used to experimentally inoculate otherwise healthy individuals in an attempt to fulfil Henle-Koch's postulates. However, only one (P180R), identified as closely related (99-100% sequence identity based on 1.4 kb 16S RNA sequence) to Vibrio tubiashii, elicited signs of disease in tank experiments. Following experimental infection (which resulted in a 90% infection rate), the pathogen was also successfully re-isolated from the diseased tissues and re-inoculated in healthy corals colonies, therefore fulfilling the final stages of Henle-Koch's postulates. Finally, we report that PWPS appears to be a temperature-dependent disease, with significantly higher tissue loss (anova: d.f. = 2, F = 39.77, P < 0.01) occurring at 30 °C [1.45 ± 0.85 cm(2) per day (mean ± SE)] compared to ambient temperatures of 28 and 26 °C (0.73 ± 0.80 cm(2) per day (mean ± SE) and 0.51 ± 0.50 cm(2) per day (mean ± SE), respectively). PMID:26193772

  5. Molecular evidence for bacterial pathogens in Ixodes ricinus ticks infesting Shetland ponies.

    Science.gov (United States)

    Skotarczak, Bogumiła; Wodecka, Beata; Rymaszewska, Anna; Adamska, Małgorzata

    2016-06-01

    Ixodes ricinus has the potential to transmit zoonotic pathogens to humans and domestic animals. The feeding I. ricinus (n = 1737) collected from 49 Shetland ponies and questing ones from vegetation (n = 371) were tested for the presence and differentiation of the bacterial species. DNA of I. ricinus ticks was examined with PCR and sequencing analysis to identify species of Borrelia burgdorferi sensu lato (Bbsl), Anaplasma phagocytophilum and Rickettsia spp. Altogether, 24.3 % I. ricinus of the infested horses and 12.4 % ticks from vegetation carried at least one pathogen species. Horse-feeding ticks (19.2 %) were significantly more frequently infected with Borrelia spp. than questing ticks (4.8 %). Among Bbsl species, in I. ricinus infesting ponies, B. garinii, B. afzelii, B. burgdorferi sensu stricto, B. valaisiana and B. lusitanie and one species, B. miyamotoi related to relapsing fever group, were detected. The 73 flaB gene sequences of Borrelia obtained from feeding I. ricinus have been deposited in GenBank. Among Rickettsia species, two were identified: R. helvetica which was dominant and R. monacensis. Infections with more than one pathogenic species, involving mostly Bbsl and R. helvetica were detected in 6.3 % of infected ticks collected from horses. Shetland ponies may play an important role in the epidemiological cycle of Bbsl and probably could contribute to the natural cycle of A. phagocytophilum and R. helvetica as host for infected ticks. The awareness about these infectious agents in ticks from ponies might be an important criterion for the risk assessment of human diseases, especially as these animals are maintained for recreational purposes. PMID:26920921

  6. Callose-mediated resistance to pathogenic intruders in plant defense-related papillae

    OpenAIRE

    Voigt, Christian A.

    2014-01-01

    Plants are exposed to a wide range of potential pathogens, which derive from diverse phyla. Therefore, plants have developed successful defense mechanisms during co-evolution with different pathogens. Besides many specialized defense mechanisms, the plant cell wall represents a first line of defense. It is actively reinforced through the deposition of cell wall appositions, so-called papillae, at sites of interaction with intruding microbial pathogens. The papilla is a complex structure that ...

  7. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens.

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R; Barany, Francis; Soper, Steven A

    2012-09-21

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft(3)). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic

  8. Pharmacodynamic evaluation of commonly prescribed oral antibiotics against respiratory bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Pignatari Antonio CC

    2011-10-01

    Full Text Available Abstract Background Upper and lower respiratory tract infections (RTIs account for a substantial portion of outpatient antibiotic utilization. However, the pharmacodynamic activity of commonly used oral antibiotic regimens has not been studied against clinically relevant pathogens. The objective of this study was to assess the probability of achieving the requisite pharmacodynamic exposure for oral antibacterial regimens commonly prescribed for RTIs in adults against bacterial isolates frequently involved in these processes (S. pneumoniae, H. influenzae, and M. catharralis. Methods Using a 5000-subject Monte Carlo simulation, the cumulative fractions of response (CFR, (i.e., probabilities of achieving requisite pharmacodynamic targets for the most commonly prescribed oral antibiotic regimens, as determined by a structured survey of medical prescription patterns, were assessed against local respiratory bacterial isolates from adults in São Paulo collected during the same time period. Minimal inhibitory concentration (MIC of 230 isolates of Streptococcus pneumoniae (103, Haemophilus influenzae (98, and Moraxella catharralis (29 from a previous local surveillance were used. Results The most commonly prescribed antibiotic regimens were azithromycin 500 mg QD, amoxicillin 500 mg TID, and levofloxacin 500 mg QD, accounting for 58% of the prescriptions. Varied doses of these agents, plus gatifloxacin, amoxicillin-clavulanate, moxifloxacin, and cefaclor made up the remaining regimens. Utilizing aggressive pharmacodynamic exposure targets, the only regimens to achieve greater than 90% CFR against all three pathogens were amoxicillin/amoxicillin-clavulanate 500 mg TID (> 91%, gatifloxacin 400 mg QD (100%, and moxifloxacin 400 mg QD (100%. Considering S. pneumoniae isolates alone, azithromycin 1000 mg QD also achieved greater than 90% CFR (91.3%. Conclusions The only regimens to achieve high CFR against all three pathogen populations in both scenarios

  9. Simultaneous Detection of Bacterial Fish Pathogens, Edwardsiella ictaluri, Flavobacterium columnnare and Aeromonas Hydrophila by Multiplex-PCR

    Science.gov (United States)

    Edwardsiella ictaluri, Flavobacterium columnare and Aeromonas hydrophila are three major bacterial pathogens of fish that cause diseases with significant economic impact on the aquaculture industry world-wide. Rapid detection of multiple infections with these bacteria in the same host is important f...

  10. Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

    Directory of Open Access Journals (Sweden)

    Lori R Shapiro

    Full Text Available Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV. We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host-plant

  11. N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa.

    Directory of Open Access Journals (Sweden)

    Lígia S Muranaka

    Full Text Available Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC. The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC, a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS. The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer. HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria.

  12. N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa.

    Science.gov (United States)

    Muranaka, Lígia S; Giorgiano, Thais E; Takita, Marco A; Forim, Moacir R; Silva, Luis F C; Coletta-Filho, Helvécio D; Machado, Marcos A; de Souza, Alessandra A

    2013-01-01

    Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS). The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer). HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL) in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria. PMID:24009716

  13. Yeast Cell Wall Extract Induces Disease Resistance against Bacterial and Fungal Pathogens in Arabidopsis thaliana and Brassica Crop

    OpenAIRE

    Narusaka, Mari; Minami, Taichi; Iwabuchi, Chikako; Hamasaki, Takashi; Takasaki, Satoko; Kawamura, Kimito; Narusaka, Yoshihiro

    2015-01-01

    Housaku Monogatari (HM) is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated incre...

  14. Broad and efficient control of major foodborne pathogenic strains of Escherichia coli by mixtures of plant-produced colicins.

    Science.gov (United States)

    Schulz, Steve; Stephan, Anett; Hahn, Simone; Bortesi, Luisa; Jarczowski, Franziska; Bettmann, Ulrike; Paschke, Anne-Katrin; Tusé, Daniel; Stahl, Chad H; Giritch, Anatoli; Gleba, Yuri

    2015-10-01

    Enterohemorrhagic Escherichia coli (EHEC) is one of the leading causes of bacterial enteric infections worldwide, causing ∼100,000 illnesses, 3,000 hospitalizations, and 90 deaths annually in the United States alone. These illnesses have been linked to consumption of contaminated animal products and vegetables. Currently, other than thermal inactivation, there are no effective methods to eliminate pathogenic bacteria in food. Colicins are nonantibiotic antimicrobial proteins, produced by E. coli strains that kill or inhibit the growth of other E. coli strains. Several colicins are highly effective against key EHEC strains. Here we demonstrate very high levels of colicin expression (up to 3 g/kg of fresh biomass) in tobacco and edible plants (spinach and leafy beets) at costs that will allow commercialization. Among the colicins examined, plant-expressed colicin M had the broadest antimicrobial activity against EHEC and complemented the potency of other colicins. A mixture of colicin M and colicin E7 showed very high activity against all major EHEC strains, as defined by the US Department of Agriculture/Food and Drug Administration. Treatments with low (less than 10 mg colicins per L) concentrations reduced the pathogenic bacterial load in broth culture by 2 to over 6 logs depending on the strain. In experiments using meats spiked with E. coli O157:H7, colicins efficiently reduced the population of the pathogen by at least 2 logs. Plant-produced colicins could be effectively used for the broad control of pathogenic E. coli in both plant- and animal-based food products and, in the United States, colicins could be approved using the generally recognized as safe (GRAS) regulatory approval pathway. PMID:26351689

  15. A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi

    Science.gov (United States)

    Mayers, Teaghan J.; Bramucci, Anna R.; Yakimovich, Kurt M.; Case, Rebecca J.

    2016-01-01

    recently been shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate. PMID:27379036

  16. A Bacterial Pathogen Displaying Temperature-Enhanced Virulence of the Microalga Emiliania huxleyi.

    Science.gov (United States)

    Mayers, Teaghan J; Bramucci, Anna R; Yakimovich, Kurt M; Case, Rebecca J

    2016-01-01

    shown to have acquired resistance against EhVs at elevated temperature, bacterial pathogens with temperature-dependent virulence, such as R11, may become much more important in the ecology of E. huxleyi in a warming climate. PMID:27379036

  17. Intercellular and intracellular signalling systems that globally control the expression of virulence genes in plant pathogenic bacteria.

    Science.gov (United States)

    Ham, Jong Hyun

    2013-04-01

    Plant pathogenic bacteria utilize complex signalling systems to control the expression of virulence genes at the cellular level and within populations. Quorum sensing (QS), an important intercellular communication mechanism, is mediated by different types of small molecules, including N-acyl homoserine lactones (AHLs), fatty acids and small proteins. AHL-mediated signalling systems dependent on the LuxI and LuxR family proteins play critical roles in the virulence of a wide range of Gram-negative plant pathogenic bacteria belonging to the Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. Xanthomonas spp. and Xylella fastidiosa, members of the Gammaproteobacteria, however, possess QS systems that are mediated by fatty acid-type diffusible signal factors (DSFs). Recent studies have demonstrated that Ax21, a 194-amino-acid protein in Xanthomonas oryzae pv. oryzae, plays dual functions in activating a rice innate immune pathway through binding to the rice XA21 pattern recognition receptor and in regulating bacterial virulence and biofilm formation as a QS signal molecule. In xanthomonads, DSF-mediated QS systems are connected with the signalling pathways mediated by cyclic diguanosine monophosphate (c-di-GMP), which functions as a second messenger for the control of virulence gene expression in these bacterial pathogens. PMID:23186372

  18. The rhizosphere effect on bacteria antagonistic towards the pathogenic fungus Verticillium differs depending on plant species and site.

    Science.gov (United States)

    Berg, Gabriele; Opelt, Katja; Zachow, Christin; Lottmann, Jana; Götz, Monika; Costa, Rodrigo; Smalla, Kornelia

    2006-05-01

    Rhizobacteria with antagonistic activity towards plant pathogens play an essential role in root growth and plant health and are influenced by plant species in their abundance and composition. To determine the extent of the effect of the plant species and of the site on the abundance and composition of bacteria with antagonistic activity towards Verticillium dahliae, bacteria isolated from the rhizosphere of two Verticillium host plants, oilseed rape and strawberry, and from bulk soil were analysed at three different locations in Germany over two growing seasons. A total of 6732 bacterial isolates screened for in vitro antagonism towards Verticillium resulted in 560 active isolates, among which Pseudomonas (77%) and Serratia (6%) were the most dominant genera. The rhizosphere effect on the antagonistic bacterial community was shown by an enhanced proportion of antagonistic isolates, by enrichment of specific amplified ribosomal DNA restriction analysis types, species and genotypes, and by a reduced diversity in the rhizosphere in comparison to bulk soil. Such an effect was influenced by the plant species and by the site of its cultivation. Altogether, 16S rRNA gene sequencing of 66 isolates resulted in the identification of 22 different species. Antagonists of the genus Serratia were preferentially isolated from oilseed rape rhizosphere, with the exception of one site. For isolates of Pseudomonas and Serratia, plant-specific and site-specific genotypes were found. PMID:16629754

  19. Biocontrol potential of Trichoderma Sp. against plant pathogens

    Directory of Open Access Journals (Sweden)

    Anand S.

    2009-12-01

    Full Text Available Forty two strains of Trichoderma sp. were isolated from cultivated lands around Bangalore andanalyzed for their antagonistic potential against Sclerotium rolfsii and Fusarium ciceri. The potential ofbiocontrol agents ultimately lies in their capacity to control pathogens in vivo. Bioefficacy studies were henceconducted using chickpea (Cicer argentums c.v. Annigeri as an experimental plant by the roll paper towelmethod. Overall the isolates T40, T35, T30 and T25 showed better antagonistic potential in addition toenhancing plant growth. The production of chitinases to break down the mycelial cell walls of fungal plantpathogens has been implicated as a major cause of biocontrol activity (Inbar and Chet, 1995. In order tostudy the mechanism of biocontrol, ten better performing strains were plated on media, amended withcolloidal chitin and Sclerotium rolfsii cell wall extract. All the isolates showed chitinolytic activity on day threeas well as day five. Production of endochitinase and exochitinase were assayed in liquid media usingcolloidal chitin amended broth. Strains T35 and T6 displayed maximum endochitinase and exochitinaseactivity. Although all strains exhibited cellulase activity, the quantum of enzyme produced was higher in T35and T6. The results also indicate a positive correlation between enzyme production and bioefficacy.

  20. No hormone to rule them all: Interactions of plant hormones during the responses of plants to pathogens.

    Science.gov (United States)

    Shigenaga, Alexandra M; Argueso, Cristiana T

    2016-08-01

    Plant hormones are essential regulators of plant growth and immunity. In the last few decades, a vast amount of information has been obtained detailing the role of different plant hormones in immunity, and how they work together to ultimately shape the outcomes of plant pathogen interactions. Here we provide an overview on the roles of the main classes of plant hormones in the regulation of plant immunity, highlighting their metabolic and signaling pathways and how plants and pathogens utilize these pathways to activate or suppress defence. PMID:27312082

  1. Selected medicinal plants used in herbal industries; their toxicity against pathogenic microorganisms

    International Nuclear Information System (INIS)

    Multi-drug resistant strains of fungi and bacteria are imposing the need for new drugs. Reliable natural sources with minor side effects are needed to control anti-human pathogenic invaders specially bacteria. Given the demands for natural products that are inherently safe and environmentally compatible, the advancement in antimicrobial potential has provided a better alternative to synthetic resistance antibiotics. In the present investigation such types of medicinal plants were selected for analyses that are used by local herbal practioners for multiple diseases. Thirty three extracts of Achillea millefolium, Acorus calamus, Arnebia nobilis, Fumaria indica, Gymnema sylvestre, Origanum vulgare, Paeonia emodi, Peganum harmala, Psoralea corylifolia, Rauwolfia serpentina and Vetiveria zizanioides in chloroform, ethanol and hexane were investigated for their antimicrobial potential. These extracts were tested against eight microorganisms including four gram negative bacterial strains viz., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella typhi, three gram positive bacterial strains Staphylococcus aureus, Bacillus subtilis and Bacillus cereus and a fungal strain viz., Candida albicans. Majority of the extracts showed marked antimicrobial potential against the tested microorganisms. (author)

  2. A Review on Biological Control of Fungal Plant Pathogens Using Microbial Antagonists

    OpenAIRE

    Mohammad Pessarakli; Asghar Heydari

    2010-01-01

    The objective of this study was to review the published research works on biological control of fungal plant diseases during past 50 years. Fungal plant pathogens are among the most important factors that cause serious losses to agricultural products every year. Biological control of plant diseases including fungal pathogens has been considered a viable alternative method to chemical control. In plant pathology, the term biocontrol applies to the use of microbial antagonists to suppress disea...

  3. Incidence of enteric bacterial pathogens in water found at the bottom of commercial freezers in calabar, southeastern Nigeria.

    Science.gov (United States)

    Eja, Matthew Egbobor; Etok, Comfort A; Asikong, Bassey E; Mboto, Clement I; Arikpo, Giddings E

    2006-03-01

    Bacteriological analysis of water that accumulates at the bottom of freezers in restaurants when the power was cut in Calabar, southeastern Nigeria, was carried out using standard procedures. Mean heterotrophic bacterial counts and Escherichia coli counts ranged from 3.1 +/- 0.02 to 7.1 +/- 0.30 x 10(4) cfu/ml and 0.2 +/- 0.10 to 0.6 +/- 0.50 x 10(4) cfu/ml, respectively, indicating heavy bacterial contamination whose source was mostly fecal. There was no significant difference (p > 0.05, 0.01) in bacterial counts between freezers. Some biochemically identified enteric bacterial pathogens were Salmonella typhi, Shigella sp, enteropathogenic E. coli, Yersinia sp, Klebsiella pneumoniae, Vibrio cholerae O1 and Vibrio parahaemolyticus. This reveals that the hygienic quality of the food items stored in the freezers and the hygienic status of the restaurants are in doubt. Infection could be going on unnoticed and thus endemicity maintained in the area. The pathogens showed alarming antibiotic resistance. The water in the freezers was a "soup" in which different species of the enteric pathogens were close to each other and could transfer drug resistance among themselves. Public health education of restaurant operators in southeastern Nigeria is recommended. PMID:17125005

  4. Cultivation and qPCR Detection of Pathogenic and Antibiotic-Resistant Bacterial Establishment in Naive Broiler Houses.

    Science.gov (United States)

    Brooks, J P; McLaughlin, M R; Adeli, A; Miles, D M

    2016-05-01

    Conventional commercial broiler production involves the rearing of more than 20,000 broilers in a single confined space for approximately 6.5 wk. This environment is known for harboring pathogens and antibiotic-resistant bacteria, but studies have focused on previously established houses with mature litter microbial populations. In the current study, a set of three naive houses were followed from inception through 11 broiler flocks and monitored for ambient climatic conditions, bacterial pathogens, and antibiotic resistance. Within the first 3 wk of the first flock cycle, 100% of litter samples were positive for and , whereas was cultivation negative but PCR positive. Antibiotic resistance genes were ubiquitously distributed throughout the litter within the first flock, approaching 10 to 10 genomic units g. Preflock litter levels were approximately 10 CFU g for heterotrophic plate count bacteria, whereas midflock levels were >10 colony forming units (CFU) g; other indicators demonstrated similar increases. The influence of intrahouse sample location was minor. In all likelihood, given that preflock levels were negative for pathogens and antibiotic resistance genes and 4 to 5 Log lower than flock levels for indicators, incoming birds most likely provided the colonizing microbiome, although other sources were not ruled out. Most bacterial groups experienced a cyclical pattern of litter contamination seen in other studies, whereas microbial stabilization required approximately four flocks. This study represents a first-of-its-kind view into the time required for bacterial pathogens and antibiotic resistance to colonize and establish in naive broiler houses. PMID:27136163

  5. A hyperparasite affects the population dynamics of a wild plant pathogen

    OpenAIRE

    Tollenaere, C.; Pernechele, B; Mäkinen, H S; Parratt, S R; Németh, M Z; Kovács, G.M.; Kiss, L.; Tack, A. J. M.; Laine, A-L

    2014-01-01

    Assessing the impact of natural enemies of plant and animal pathogens on their host's population dynamics is needed to determine the role of hyperparasites in affecting disease dynamics, and their potential for use in efficient control strategies of pathogens. Here, we focus on the long-term study describing metapopulation dynamics of an obligate pathogen, the powdery mildew (Podosphaera plantaginis) naturally infecting its wild host plant (Plantago lanceolata) in the fragmented landscape of ...

  6. Antimicrobial potential of Halophilic actinomycetes against multi drug resistant (MDR) ventilator associated pneumonia causing bacterial pathogens.

    Science.gov (United States)

    Aslam, Sana; Sajid, Imran

    2016-03-01

    A collection of forty halophilic actinomycetes isolated from water and mud samples of the saline lake at Kalar Kahar, salt range, Pakistan, was screened to investigate their antimicrobial potential against multi drug resistant (MDR) ventilator associated pneumonia causing bacterial pathogens. The isolates exhibited significant tolerance to alkaline conditions and grew well at pH 9-11. The taxonomic status of the isolated strains was determined by morphological, biochemical and physiological characterization and by 16s rRNA gene sequencing. The results revealed that majority of the isolates (90%) belong to the genus Streptomyces. Most of the isolates exhibited remarkable antimicrobial activity up to 20mm zone of inhibition against MDR ventilator associated pneumonia causing bacteria including Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Enterobacter and Acinetobacter spp. Additionally the isolates showed moderate to high cytotoxicity in the range of 40 to 80% larval mortality against Artemia salina in a micro well cytotoxicity assay. The chemical screening or the so called metabolic fingerprinting of the methanolic extracts of each isolate, by thin layer chromatography (TLC) using various staining reagents and by high performance liquid chromatography (HPLC-UV), indicated an impressive diversity of the compounds produced by these strains. The study reveals that these halophilic actinomycetes are a promising source of bioactive compounds. The preparative scale fermentation, isolation, purification and structure elucidation of the compounds produced by them may yield novel antimicrobial or chemotherapeutic agents. PMID:27087086

  7. Microfluidic system for the identification of bacterial pathogens causing urinary tract infections

    Science.gov (United States)

    Becker, Holger; Hlawatsch, Nadine; Haraldsson, Tommy; van der Wijngaart, Wouter; Lind, Anders; Malhotra-Kumar, Surbi; Turlej-Rogacka, Agata; Goossens, Herman

    2015-03-01

    Urinary tract infections (UTIs) are among the most common bacterial infections and pose a significant healthcare burden. The growing trend in antibiotic resistance makes it mandatory to develop diagnostic kits which allow not only the determination of a pathogen but also the antibiotic resistances. We have developed a microfluidic cartridge which takes a direct urine sample, extracts the DNA, performs an amplification using batch-PCR and flows the sample over a microarray which is printed into a microchannel for fluorescence detection. The cartridge is injection-molded out of COP and contains a set of two-component injection-molded rotary valves to switch between input and to isolate the PCR chamber during thermocycling. The hybridization probes were spotted directly onto a functionalized section of the outlet microchannel. We have been able to successfully perform PCR of E.coli in urine in this chip and perform a fluorescence detection of PCR products. An upgraded design of the cartridge contains the buffers and reagents in blisters stored on the chip.

  8. Antibacterial potential of silver nanoparticles against isolated urinary tract infectious bacterial pathogens

    Science.gov (United States)

    Jacob Inbaneson, Samuel; Ravikumar, Sundaram; Manikandan, Nachiappan

    2011-12-01

    The silver nanoparticles were synthesized by chemical reduction method and the nanoparticles were characterized using ultraviolet-visible (UV-Vis) absorption spectroscopy and X-ray diffraction (XRD) studies. The synthesized silver nanoparticles were investigated to evaluate the antibacterial activity against urinary tract infectious (UTIs) bacterial pathogens. Thirty-two bacteria were isolated from mid urine samples of 25 male and 25 female patients from Thondi, Ramanathapuram District, Tamil Nadu, India and identified by conventional methods. Escherichia coli was predominant (47%) followed by Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%), Enterobacter sp. (6%), Proteus morganii (3%) and Staphylococcus aureus (3%). The antibacterial activity of silver nanoparticles was evaluated by disc diffusion assay. P. aeruginosa showed maximum sensitivity (11 ± 0.58 mm) followed by Enterobacter sp. (8 ± 0.49 mm) at a concentration of 20 μg disc-1 and the sensitivity was highly comparable with the positive control kanamycin and tetracycline. K. pneumoniae, E. coli, P. morganii and S. aureus showed no sensitivity against all the tested concentrations of silver nanoparticles. The results provided evidence that, the silver nanoparticles might indeed be the potential sources to treat urinary tract infections caused by P. aeruginosa and Enterobacter sp.

  9. Secreted and immunogenic proteins produced by the honeybee bacterial pathogen, Paenibacillus larvae.

    Science.gov (United States)

    Antúnez, Karina; Anido, Matilde; Evans, Jay D; Zunino, Pablo

    2010-03-24

    American Foulbrood is a severe disease affecting larvae of honeybee Apis mellifera, causing significant decrease in the honeybee population, beekeeping industries and agricultural production. In spite of its importance, little is known about the virulence factors secreted by Paenibacillus larvae during larval infection. The aim of the present work was to perform a first approach to the identification and characterization of P. larvae secretome. P. larvae secreted proteins were analyzed by SDS-PAGE and identified by MALDI-TOF. Protein toxicity was evaluated using an experimental model based on feeding of A. mellifera larvae and immunogenicity was evaluated by Western blot, using an antiserum raised against cells and spores of P. larvae. Ten different proteins were identified among P. larvae secreted proteins, including proteins involved in transcription, metabolism, translation, cell envelope, transport, protein folding, degradation of polysaccharides and motility. Although most of these proteins are cytosolic, many of them have been previously detected in the extracellular medium of different Bacillus spp. cultures and have been related to virulence. The secreted proteins resulted highly toxic and immunogenic when larvae were exposed using an experimental model. This is the first description of proteins secreted by the honeybee pathogen P. larvae. This information may be relevant for the elucidation of bacterial pathogenesis mechanisms. PMID:19781868

  10. The impact of hypoxia on intestinal epithelial cell functions: consequences for invasion by bacterial pathogens.

    Science.gov (United States)

    Zeitouni, Nathalie E; Chotikatum, Sucheera; von Köckritz-Blickwede, Maren; Naim, Hassan Y

    2016-12-01

    The maintenance of oxygen homeostasis in human tissues is mediated by several cellular adaptations in response to low-oxygen stress, called hypoxia. A decrease in tissue oxygen levels is initially counteracted by increasing local blood flow to overcome diminished oxygenation and avoid hypoxic stress. However, studies have shown that the physiological oxygen concentrations in several tissues are much lower than atmospheric (normoxic) conditions, and the oxygen supply is finely regulated in individual cell types. The gastrointestinal tract has been described to subsist in a state of physiologically low oxygen level and is thus depicted as a tissue in the state of constant low-grade inflammation. The intestinal epithelial cell layer plays a vital role in the immune response to inflammation and infections that occur within the intestinal tissue and is involved in many of the adaptation responses to hypoxic stress. This is especially relevant in the context of inflammatory disorders, such as inflammatory bowel disease (IBD). Therefore, this review aims to describe the intestinal epithelial cellular response to hypoxia and the consequences for host interactions with invading gastrointestinal bacterial pathogens. PMID:27002817

  11. Multiple candidate effectors from the oomycete pathogen Hyaloperonospora arabidopsidis suppress host plant immunity.

    Directory of Open Access Journals (Sweden)

    Georgina Fabro

    2011-11-01

    Full Text Available Oomycete pathogens cause diverse plant diseases. To successfully colonize their hosts, they deliver a suite of effector proteins that can attenuate plant defenses. In the oomycete downy mildews, effectors carry a signal peptide and an RxLR motif. Hyaloperonospora arabidopsidis (Hpa causes downy mildew on the model plant Arabidopsis thaliana (Arabidopsis. We investigated if candidate effectors predicted in the genome sequence of Hpa isolate Emoy2 (HaRxLs were able to manipulate host defenses in different Arabidopsis accessions. We developed a rapid and sensitive screening method to test HaRxLs by delivering them via the bacterial type-three secretion system (TTSS of Pseudomonas syringae pv tomato DC3000-LUX (Pst-LUX and assessing changes in Pst-LUX growth in planta on 12 Arabidopsis accessions. The majority (~70% of the 64 candidates tested positively contributed to Pst-LUX growth on more than one accession indicating that Hpa virulence likely involves multiple effectors with weak accession-specific effects. Further screening with a Pst mutant (ΔCEL showed that HaRxLs that allow enhanced Pst-LUX growth usually suppress callose deposition, a hallmark of pathogen-associated molecular pattern (PAMP-triggered immunity (PTI. We found that HaRxLs are rarely strong avirulence determinants. Although some decreased Pst-LUX growth in particular accessions, none activated macroscopic cell death. Fewer HaRxLs conferred enhanced Pst growth on turnip, a non-host for Hpa, while several reduced it, consistent with the idea that turnip's non-host resistance against Hpa could involve a combination of recognized HaRxLs and ineffective HaRxLs. We verified our results by constitutively expressing in Arabidopsis a sub-set of HaRxLs. Several transgenic lines showed increased susceptibility to Hpa and attenuation of Arabidopsis PTI responses, confirming the HaRxLs' role in Hpa virulence. This study shows TTSS screening system provides a useful tool to test whether

  12. Multiple activities of the plant pathogen type III effector proteins WtsE and AvrE require WxxxE motifs.

    Science.gov (United States)

    Ham, Jong Hyun; Majerczak, Doris R; Nomura, Kinya; Mecey, Christy; Uribe, Francisco; He, Sheng-Yang; Mackey, David; Coplin, David L

    2009-06-01

    The broadly conserved AvrE-family of type III effectors from gram-negative plant-pathogenic bacteria includes important virulence factors, yet little is known about the mechanisms by which these effectors function inside plant cells to promote disease. We have identified two conserved motifs in AvrE-family effectors: a WxxxE motif and a putative C-terminal endoplasmic reticulum membrane retention/retrieval signal (ERMRS). The WxxxE and ERMRS motifs are both required for the virulence activities of WtsE and AvrE, which are major virulence factors of the corn pathogen Pantoea stewartii subsp. stewartii and the tomato or Arabidopsis pathogen Pseudomonas syringae pv. tomato, respectively. The WxxxE and the predicted ERMRS motifs are also required for other biological activities of WtsE, including elicitation of the hypersensitive response in nonhost plants and suppression of defense responses in Arabidopsis. A family of type III effectors from mammalian bacterial pathogens requires WxxxE and subcellular targeting motifs for virulence functions that involve their ability to mimic activated G-proteins. The conservation of related motifs and their necessity for the function of type III effectors from plant pathogens indicates that disturbing host pathways by mimicking activated host G-proteins may be a virulence mechanism employed by plant pathogens as well. PMID:19445595

  13. Structured literature review of responses of cattle to viral and bacterial pathogens causing bovine respiratory disease complex.

    Science.gov (United States)

    Grissett, G P; White, B J; Larson, R L

    2015-01-01

    Bovine respiratory disease (BRD) is an economically important disease of cattle and continues to be an intensely studied topic. However, literature summarizing the time between pathogen exposure and clinical signs, shedding, and seroconversion is minimal. A structured literature review of the published literature was performed to determine cattle responses (time from pathogen exposure to clinical signs, shedding, and seroconversion) in challenge models using common BRD viral and bacterial pathogens. After review a descriptive analysis of published studies using common BRD pathogen challenge studies was performed. Inclusion criteria were single pathogen challenge studies with no treatment or vaccination evaluating outcomes of interest: clinical signs, shedding, and seroconversion. Pathogens of interest included: bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BHV-1), parainfluenza-3 virus, bovine respiratory syncytial virus, Mannheimia haemolytica, Mycoplasma bovis, Pastuerella multocida, and Histophilus somni. Thirty-five studies and 64 trials were included for analysis. The median days to the resolution of clinical signs after BVDV challenge was 15 and shedding was not detected on day 12 postchallenge. Resolution of BHV-1 shedding resolved on day 12 and clinical signs on day 12 postchallenge. Bovine respiratory syncytial virus ceased shedding on day 9 and median time to resolution of clinical signs was on day 12 postchallenge. M. haemolytica resolved clinical signs 8 days postchallenge. This literature review and descriptive analysis can serve as a resource to assist in designing challenge model studies and potentially aid in estimation of duration of clinical disease and shedding after natural pathogen exposure. PMID:25929158

  14. Pathogen Propagation Model with Superinfection in Vegetatively Propagated Plants on Lattice Space

    Science.gov (United States)

    Sakai, Yuma; Takada, Takenori

    2016-01-01

    Many clonal plants have two reproductive patterns, seed propagation and vegetative propagation. By vegetative propagation, plants reproduce the genetically identical offspring with a low mortality, because resources are supplied from the other individuals through interconnected ramets at vegetative-propagated offspring. However, the ramets transport not only resources but also systemic pathogen. Pathogens evolve to establish and spread widely within the plant population. The superinfection, which is defined as the ability that an established pathogen spreads widely by infecting to already-infected individuals with other strains of a pathogen, is important to the evolution of pathogens. We examine the dynamics of plant reproduction and pathogen propagation considering spatial structure and the effect of superinfection on genetic diversity of pathogen by analysis of several models, 1-strain and multiple-strain models, on two-dimensional square lattice. In the analysis of 1-strain model, we derive equilibrium value by mean-field approximation and pair approximation, and its local stability by Routh-Hurwitz stability criterion. In the multiple-strain models, we analyze the dynamics by numerical simulation of mean-field approximation, pair approximation and Monte Carlo simulation. Through the analyses, we show the effect of parameter values to dynamics of models, such as transition of dominant strain of pathogen, competition between plants and pathogens and density of individuals. As a result, (i) The strain with intermediate cost becomes dominant when both superinfection rate and growth rate are low. (ii) The competition between plants and pathogens occurs in the phase of coexistence of various strains by pair approximation and Monte Carlo simulation. (iii) Too high growth rate leads to the decrease of plant population in all models. (iv) Pathogens are easy to maintain their genetic diversity with low superinfection rate. However, if they do not superinfect, the

  15. Pathogen Propagation Model with Superinfection in Vegetatively Propagated Plants on Lattice Space.

    Science.gov (United States)

    Sakai, Yuma; Takada, Takenori

    2016-01-01

    Many clonal plants have two reproductive patterns, seed propagation and vegetative propagation. By vegetative propagation, plants reproduce the genetically identical offspring with a low mortality, because resources are supplied from the other individuals through interconnected ramets at vegetative-propagated offspring. However, the ramets transport not only resources but also systemic pathogen. Pathogens evolve to establish and spread widely within the plant population. The superinfection, which is defined as the ability that an established pathogen spreads widely by infecting to already-infected individuals with other strains of a pathogen, is important to the evolution of pathogens. We examine the dynamics of plant reproduction and pathogen propagation considering spatial structure and the effect of superinfection on genetic diversity of pathogen by analysis of several models, 1-strain and multiple-strain models, on two-dimensional square lattice. In the analysis of 1-strain model, we derive equilibrium value by mean-field approximation and pair approximation, and its local stability by Routh-Hurwitz stability criterion. In the multiple-strain models, we analyze the dynamics by numerical simulation of mean-field approximation, pair approximation and Monte Carlo simulation. Through the analyses, we show the effect of parameter values to dynamics of models, such as transition of dominant strain of pathogen, competition between plants and pathogens and density of individuals. As a result, (i) The strain with intermediate cost becomes dominant when both superinfection rate and growth rate are low. (ii) The competition between plants and pathogens occurs in the phase of coexistence of various strains by pair approximation and Monte Carlo simulation. (iii) Too high growth rate leads to the decrease of plant population in all models. (iv) Pathogens are easy to maintain their genetic diversity with low superinfection rate. However, if they do not superinfect, the

  16. Evolution of host range in Coleosporium ipomoeae, a plant pathogen with multiple hosts.

    Science.gov (United States)

    Chappell, Thomas M; Rausher, Mark D

    2016-05-10

    Plants and their pathogens coevolve locally. Previous investigations of one host-one pathogen systems have demonstrated that natural selection favors pathogen genotypes that are virulent on a broad range of host genotypes. In the present study, we examine a system consisting of one pathogen species that infects three host species in the morning glory genus Ipomoea. We show that many pathogen genotypes can infect two or three of the host species when tested on plants from nonlocal communities. By contrast, pathogen genotypes are highly host-specific, infecting only one host species, when tested on host species from the local community. This pattern indicates that within-community evolution narrows the host breadth of pathogen genotypes. Possible evolutionary mechanisms include direct selection for narrow host breadth due to costs of virulence and evolution of ipomoea resistance in the host species. PMID:27114547

  17. Arranging the bouquet of disease: floral traits and the transmission of plant and animal pathogens.

    Science.gov (United States)

    McArt, Scott H; Koch, Hauke; Irwin, Rebecca E; Adler, Lynn S

    2014-05-01

    Several floral microbes are known to be pathogenic to plants or floral visitors such as pollinators. Despite the ecological and economic importance of pathogens deposited in flowers, we often lack a basic understanding of how floral traits influence disease transmission. Here, we provide the first systematic review regarding how floral traits attract vectors (for plant pathogens) or hosts (for animal pathogens), mediate disease establishment and evolve under complex interactions with plant mutualists that can be vectors for microbial antagonists. Attraction of floral visitors is influenced by numerous phenological, morphological and chemical traits, and several plant pathogens manipulate floral traits to attract vectors. There is rapidly growing interest in how floral secondary compounds and antimicrobial enzymes influence disease establishment in plant hosts. Similarly, new research suggests that consumption of floral secondary compounds can reduce pathogen loads in animal pollinators. Given recent concerns about pollinator declines caused in part by pathogens, the role of floral traits in mediating pathogen transmission is a key area for further research. We conclude by discussing important implications of floral transmission of pathogens for agriculture, conservation and human health, suggesting promising avenues for future research in both basic and applied biology. PMID:24528408

  18. Non-pathogenic Rhizobium radiobacter F4 deploys plant beneficial activity independent of its host Piriformospora indica.

    Science.gov (United States)

    Glaeser, Stefanie P; Imani, Jafargholi; Alabid, Ibrahim; Guo, Huijuan; Kumar, Neelendra; Kämpfer, Peter; Hardt, Martin; Blom, Jochen; Goesmann, Alexander; Rothballer, Michael; Hartmann, Anton; Kogel, Karl-Heinz

    2016-04-01

    The Alphaproteobacterium Rhizobium radiobacter F4 (RrF4) was originally characterized as an endofungal bacterium in the beneficial endophytic Sebacinalean fungus Piriformospora indica. Although attempts to cure P. indica from RrF4 repeatedly failed, the bacterium can easily be grown in pure culture. Here, we report on RrF4's genome and the beneficial impact the free-living bacterium has on plants. In contrast to other endofungal bacteria, the genome size of RrF4 is not reduced. Instead, it shows a high degree of similarity to the plant pathogenic R. radiobacter (formerly: Agrobacterium tumefaciens) C58, except vibrant differences in both the tumor-inducing (pTi) and the accessor (pAt) plasmids, which can explain the loss of RrF4's pathogenicity. Similar to its fungal host, RrF4 colonizes plant roots without host preference and forms aggregates of attached cells and dense biofilms at the root surface of maturation zones. RrF4-colonized plants show increased biomass and enhanced resistance against bacterial leaf pathogens. Mutational analysis showed that, similar to P. indica, resistance mediated by RrF4 was dependent on the plant's jasmonate-based induced systemic resistance (ISR) pathway. Consistent with this, RrF4- and P. indica-induced pattern of defense gene expression were similar. In clear contrast to P. indica, but similar to plant growth-promoting rhizobacteria, RrF4 colonized not only the root outer cortex but also spread beyond the endodermis into the stele. On the basis of our findings, RrF4 is an efficient plant growth-promoting bacterium. PMID:26495996

  19. Highways in the sky: scales of atmospheric transport of plant pathogens.

    Science.gov (United States)

    Schmale, David G; Ross, Shane D

    2015-01-01

    Many high-risk plant pathogens are transported over long distances (hundreds of meters to thousands of kilometers) in the atmosphere. The ability to track the movement of these pathogens in the atmosphere is essential for forecasting disease spread and establishing effective quarantine measures. Here, we discuss the scales of atmospheric dispersal of plant pathogens along a transport continuum (pathogen scale, farm scale, regional scale, and continental scale). Growers can use risk information at each of these dispersal scales to assist in making plant disease management decisions, such as the timely application of appropriate pesticides. Regional- and continental-scale atmospheric features known as Lagrangian coherent structures (LCSs) may shuffle plant pathogens along highways in the sky. A promising new method relying on overlapping turbulent back-trajectories of pathogen-laden parcels of air may assist in localizing potential inoculum sources, informing local and/or regional management efforts such as conservation tillage. The emergence of unmanned aircraft systems (UASs, or drones) to sample plant pathogens in the lower atmosphere, coupled with source localization efforts, could aid in mitigating the spread of high-risk plant pathogens. PMID:26047561

  20. Foliar endophytic fungi as potential protectors from pathogens in myrmecophytic Acacia plants

    OpenAIRE

    González-Teuber, M.; Jimenez-Aleman, G.; Boland, W

    2014-01-01

    In defensive ant-plant interactions myrmecophytic plants express reduced chemical defense in their leaves to protect themselves from pathogens, and it seems that mutualistic partners are required to make up for this lack of defensive function. Previously, we reported that mutualistic ants confer plants of Acacia hindsii protection from pathogens, and that the protection is given by the ant-associated bacteria. Here, we examined whether foliar endophytic fungi may potentially act as a new part...

  1. Effects of Plant Biomass, Plant Diversity, and Water Content on Bacterial Communities in Soil Lysimeters: Implications for the Determinants of Bacterial Diversity▿ †

    OpenAIRE

    Zul, Delita; Denzel, Sabine; Kotz, Andrea; Overmann, Jörg

    2007-01-01

    Soils may comprise tens of thousands to millions of bacterial species. It is still unclear whether this high level of diversity is governed by functional redundancy or by a multitude of ecological niches. In order to address this question, we analyzed the reproducibility of bacterial community composition after different experimental manipulations. Soil lysimeters were planted with four different types of plant communities, and the water content was adjusted. Group-specific phylogenetic finge...

  2. Prophage-Mediated Dynamics of ‘Candidatus Liberibacter asiaticus’ Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing

    OpenAIRE

    Lijuan Zhou; Powell, Charles A.; Wenbin Li; Mike Irey; Yongping Duan

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by s...

  3. Molecular Interactions between the Citrus Bacterial Pathogen Candidatus Liberbacter asiaticus and Its Insect Vector the Asian Citrus Psyllid Diaphorina citri

    OpenAIRE

    Wang, Linling; Killiny, Nabil

    2014-01-01

    Huanglongbing (HLB), the most serious disease of citrus, is attributed in the United States to Candidatus Liberibacter asiaticus (CLas), a gram-negative, phloem-restricted α-proteobacterium transmitted by the Asian citrus psyllid (Diaphorina citri). Despite the fact that the psyllid is well recognized as the vector of CLas, to the best of our knowledge, little research has so far been conducted on molecular interactions between CLas and the psyllid. Many gram-negative bacterial pathogens have...

  4. Prophage-Mediated Dynamics of ‘Candidatus Liberibacter asiaticus’ Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing

    OpenAIRE

    Zhou, Lijuan; Powell, Charles A.; Li, Wenbin; Irey, Mike; Duan, Yongping

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus’ (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by s...

  5. Prevalence of bacterial respiratory pathogens in the nasopharynx in breast-fed versus formula-fed infants.

    OpenAIRE

    Kaleida, P H; Nativio, D G; Chao, H P; Cowden, S N

    1993-01-01

    In several studies, breast-feeding has been associated with decreased frequency or duration of otitis media episodes. If a causal relationship exists, the mechanism of protection of breast-feeding has not been established. We hypothesized that infants who are breast-fed, compared with infants who are formula-fed, have a lower prevalence of nasopharyngeal colonization with the bacterial respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Streptococcu...

  6. Exploration and conservation of bacterial genetic resources as bacteriocin producing inhibitory microorganisms to pathogen bacteria in livestock

    OpenAIRE

    2013-01-01

    Exploration and conservation of microorganisms producing bacteriocin was done as the primary study towards the collection of potential bacteria and its application in improving livestock health condition and inhibit food borne pathogens. Diferent kinds of samples such as beef cattle rectal swab, rumen fluids, cow’s milk, chicken gut content, goat’s milk were collected at Bogor cattle slaughter houses, poultry slaughter houses, dairy cattle and goat farms. A total of 452 bacterial isolates con...

  7. Enteric bacterial pathogens in children with diarrhea in Niger: diversity and antimicrobial resistance.

    Directory of Open Access Journals (Sweden)

    Céline Langendorf

    Full Text Available Although rotavirus is the leading cause of severe diarrhea among children in sub-Saharan Africa, better knowledge of circulating enteric pathogenic bacteria and their antimicrobial resistance is crucial for prevention and treatment strategies.As a part of rotavirus gastroenteritis surveillance in Maradi, Niger, we performed stool culture on a sub-population of children under 5 with moderate-to-severe diarrhea between April 2010 and March 2012. Campylobacter, Shigella and Salmonella were sought with conventional culture and biochemical methods. Shigella and Salmonella were serotyped by slide agglutination. Enteropathogenic Escherichia coli (EPEC were screened by slide agglutination with EPEC O-typing antisera and confirmed by detection of virulence genes. Antimicrobial susceptibility was determined by disk diffusion. We enrolled 4020 children, including 230 with bloody diarrhea. At least one pathogenic bacterium was found in 28.0% of children with watery diarrhea and 42.2% with bloody diarrhea. Mixed infections were found in 10.3% of children. EPEC, Salmonella and Campylobacter spp. were similarly frequent in children with watery diarrhea (11.1%, 9.2% and 11.4% respectively and Shigella spp. were the most frequent among children with bloody diarrhea (22.1%. The most frequent Shigella serogroup was S. flexneri (69/122, 56.5%. The most frequent Salmonella serotypes were Typhimurimum (71/355, 20.0%, Enteritidis (56/355, 15.8% and Corvallis (46/355, 13.0%. The majority of putative EPEC isolates was confirmed to be EPEC (90/111, 81.1%. More than half of all Enterobacteriaceae were resistant to amoxicillin and co-trimoxazole. Around 13% (46/360 Salmonella exhibited an extended-spectrum beta-lactamase phenotype.This study provides updated information on enteric bacteria diversity and antibiotic resistance in the Sahel region, where such data are scarce. Whether they are or not the causative agent of diarrhea, bacterial infections and their antibiotic

  8. Pre-adapting parasitic phages to a pathogen leads to increased pathogen clearance and lowered resistance evolution with Pseudomonas aeruginosa cystic fibrosis bacterial isolates.

    Science.gov (United States)

    Friman, V-P; Soanes-Brown, D; Sierocinski, P; Molin, S; Johansen, H K; Merabishvili, M; Pirnay, J-P; De Vos, D; Buckling, A

    2016-01-01

    Recent years have seen renewed interest in phage therapy--the use of viruses to specifically kill disease-causing bacteria--because of the alarming rise in antibiotic resistance. However, a major limitation of phage therapy is the ease at with bacteria can evolve resistance to phages. Here, we determined whether in vitro experimental coevolution can increase the efficiency of phage therapy by limiting the resistance evolution of intermittent and chronic cystic fibrosis Pseudomonas aeruginosa lung isolates to four different phages. We first pre-adapted all phage strains against all bacterial strains and then compared the efficacy of pre-adapted and nonadapted phages against ancestral bacterial strains. We found that evolved phages were more efficient in reducing bacterial densities than ancestral phages. This was primarily because only 50% of bacterial strains were able to evolve resistance to evolved phages, whereas all bacteria were able to evolve some level of resistance to ancestral phages. Although the rate of resistance evolution did not differ between intermittent and chronic isolates, it incurred a relatively higher growth cost for chronic isolates when measured in the absence of phages. This is likely to explain why evolved phages were more effective in reducing the densities of chronic isolates. Our data show that pathogen genotypes respond differently to phage pre-adaptation, and as a result, phage therapies might need to be individually adjusted for different patients. PMID:26476097

  9. Chemosensitization of plant pathogenic fungi to agricultural fungicides

    Science.gov (United States)

    Continual use of fungicides in agriculture often results in development of resistance in pathogens. A new strategy to aid in overcoming or minimizing this problem is enhancement of pathogen sensitivity to fungicides by chemosensitization. This involves combining fungicides with certain non-fungicida...

  10. Bacterial pathogens and their antimicrobial susceptibility in Otukpo Benue state of Nigeria

    Institute of Scientific and Technical Information of China (English)

    Okwori EE; Nwadioha SI; Nwokedi EOP; Odimayo M; Jombo GTA

    2011-01-01

    Objective:To isolate bacterial pathogens and test for their antibiotic susceptibility. Methods:A total of 20 000 samples from 9 different clinical sites were processed in the laboratory between 1987 to 2000. The specimens were inoculated on the appropriate media for the isolation of the bacteria. Biochemical and serology tests were carried out on the organisms to confirm the type of bacteria isolated. Antibiotic susceptibility test was also carried out on each of the bacteria isolated. Results:A total of 18 520 bacteria were isolated from the specimens. The specimens were from nine different clinical sites, i.e. wound accounted for 22.84%, urine 31.67%, blood 12.38%, genital 7.70%, sputum 6.81%, stool 6.28%, cerebrospinal fluid 5.98%, aspirates 3.85%and ear/throat swabs were 2.49%. Gram negative bacteria accounted for 76%of isolates. The main species were Pseudomonas 2 238 (12.08%), Escherichia coli (E. coli) 2 073 (11.19%) and Staphylococcus aureus (S. aureus) which accounted for 2 511 (13.56%) of the total isolates. S. aureus showed 70%and 65%resistance to penicillin and ampicillin, respectively. Surprisingly, 40%of the organism was resistant to cloxacillin. E. coli showed 47%and 42%resistance to ampicillin and gentamicin, respectively. 49%of Salmonella typhi was resistant to chloramphenicol while 37%of Neisseria meningitidis was resistant to penicillin. Conclusions: The rate of bacteria isolated from the clinical specimens is high and antibiotic sensitivity pattern of the organisms vary from one antibiotic to the other.

  11. Iron Limitation Triggers Early Egress by the Intracellular Bacterial Pathogen Legionella pneumophila.

    Science.gov (United States)

    O'Connor, Tamara J; Zheng, Huaixin; VanRheenen, Susan M; Ghosh, Soma; Cianciotto, Nicholas P; Isberg, Ralph R

    2016-08-01

    Legionella pneumophila is an intracellular bacterial pathogen that replicates in alveolar macrophages, causing a severe form of pneumonia. Intracellular growth of the bacterium depends on its ability to sequester iron from the host cell. In the L. pneumophila strain 130b, one mechanism used to acquire this essential nutrient is the siderophore legiobactin. Iron-bound legiobactin is imported by the transport protein LbtU. Here, we describe the role of LbtP, a paralog of LbtU, in iron acquisition in the L. pneumophila strain Philadelphia-1. Similar to LbtU, LbtP is a siderophore transport protein and is required for robust growth under iron-limiting conditions. Despite their similar functions, however, LbtU and LbtP do not contribute equally to iron acquisition. The Philadelphia-1 strain lacking LbtP is more sensitive to iron deprivation in vitro Moreover, LbtP is important for L. pneumophila growth within macrophages while LbtU is dispensable. These results demonstrate that LbtP plays a dominant role over LbtU in iron acquisition. In contrast, loss of both LbtP and LbtU does not impair L. pneumophila growth in the amoebal host Acanthamoeba castellanii, demonstrating a host-specific requirement for the activities of these two transporters in iron acquisition. The growth defect of the ΔlbtP mutant in macrophages is not due to alterations in growth kinetics. Instead, the absence of LbtP limits L. pneumophila replication and causes bacteria to prematurely exit the host cell. These results demonstrate the existence of a preprogrammed exit strategy in response to iron limitation that allows L. pneumophila to abandon the host cell when nutrients are exhausted. PMID:27185787

  12. Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators

    Science.gov (United States)

    Haack, S.K.; Duris, J.W.; Fogarty, L.R.; Kolpin, D.W.; Focazio, M.J.; Furlong, E.T.; Meyer, M.T.

    2009-01-01

    The objective of this study was to compare fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli [EC], and enterococci [ENT]) concentrations with a wide array of typical organic wastewater chemicals and selected bacterial genes as indicators of fecal pollution in water samples collected at or near 18 surface water drinking water intakes. Genes tested included esp (indicating human-pathogenic ENT) and nine genes associated with various animal sources of shiga-toxin-producing EC (STEC). Fecal pollution was indicated by genes and/or chemicals for 14 of the 18 tested samples, with little relation to FIB standards. Of 13 samples with genes (indicating varying animal sources of STEC) were detected in eight. Only the EC eaeA gene was positively correlated with FIB concentrations. Human-source fecal pollution was indicated by the esp gene and the human pharmaceutical carbamazepine in one of the nine samples that met all FIB recreational water quality standards. Escherichia coli rfbO157 and stx2c genes, which are typically associated with cattle sources and are of potential human health significance, were detected in one sample in the absence of tested chemicals. Chemical and gene-based indicators of fecal contamination may be present even when FIB standards are met, and some may, unlike FIB, indicate potential sources. Application of multiple water quality indicators with variable environmental persistence and fate may yield greater confidence in fecal pollution assessment and may inform remediation decisions. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  13. In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

    Institute of Scientific and Technical Information of China (English)

    Muhammad Kamruzzaman; S.M. Nayeemul Bari; Shah M. Faruque

    2013-01-01

    Objective: To investigate in vitro and in vivo antibacterial potentials of Vitex negundo (V. negundo) leaf extracts against diverse enteric pathogens. Methods: Water and methanol extracts of V. negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion, viable bacterial cell count methods, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). Results: Methanol extract of V. negundo leaves showed potent antibacterial activity (inhibition zone: 9.9-22.6 mm, MIC:200-3 200 μg/mL, MBC: 200-6 400 μg/mL) against all the pathogenic enteric bacteria (Vibriocholerae , Vibrio parahaemolyticus, Vibrio mimicus, Echerichia coli, Shigella spps., and Aeromonas spps) tested. Methanol extract of V. negundo leaves showed potent bactericidal activity both in vitro laboratory conditions (MBC, 200-400 μg/mL) and in the intestinal environment (Dose, 1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae, the major causative agent of cholera. Furthermore, assays using the mice cholera model showed that V. negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate (P<0.0001). Conclusions: For the first time we showed that methanol extract of V. negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions. Therefore, it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

  14. Bacterial microcompartments as metabolic modules for plant synthetic biology.

    Science.gov (United States)

    Gonzalez-Esquer, C Raul; Newnham, Sarah E; Kerfeld, Cheryl A

    2016-07-01

    Bacterial microcompartments (BMCs) are megadalton-sized protein assemblies that enclose segments of metabolic pathways within cells. They increase the catalytic efficiency of the encapsulated enzymes while sequestering volatile or toxic intermediates from the bulk cytosol. The first BMCs discovered were the carboxysomes of cyanobacteria. Carboxysomes compartmentalize the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) with carbonic anhydrase. They enhance the carboxylase activity of RuBisCO by increasing the local concentration of CO2 in the vicinity of the enzyme's active site. As a metabolic module for carbon fixation, carboxysomes could be transferred to eukaryotic organisms (e.g. plants) to increase photosynthetic efficiency. Within the scope of synthetic biology, carboxysomes and other BMCs hold even greater potential when considered a source of building blocks for the development of nanoreactors or three-dimensional scaffolds to increase the efficiency of either native or heterologously expressed enzymes. The carboxysome serves as an ideal model system for testing approaches to engineering BMCs because their expression in cyanobacteria provides a sensitive screen for form (appearance of polyhedral bodies) and function (ability to grow on air). We recount recent progress in the re-engineering of the carboxysome shell and core to offer a conceptual framework for the development of BMC-based architectures for applications in plant synthetic biology. PMID:26991644

  15. The bacterial effector DspA/E is toxic in Arabidopsis thaliana and is required for multiplication and survival of fire blight pathogen.

    Science.gov (United States)

    Degrave, Alexandre; Moreau, Manon; Launay, Alban; Barny, Marie-Anne; Brisset, Marie-Noëlle; Patrit, Oriane; Taconnat, Ludivine; Vedel, Regine; Fagard, Mathilde

    2013-06-01

    The type III effector DspA/E is an essential pathogenicity factor of the phytopathogenic bacterium Erwinia amylovora. We showed that DspA/E was required for transient bacterial growth in nonhost Arabidopsis thaliana leaves, as an E. amylovora dspA/E mutant was unable to grow. We expressed DspA/E in A. thaliana transgenic plants under the control of an oestradiol-inducible promoter, and found that DspA/E expressed in planta restored the growth of a dspA/E mutant. DspA/E expression in these transgenic plants led to the modulation by at least two-fold of the expression of 384 genes, mostly induced (324 genes). Both induced and repressed genes contained high proportions of defence genes. DspA/E expression ultimately resulted in plant cell death without requiring a functional salicylic acid signalling pathway. Analysis of A. thaliana transgenic seedlings expressing a green fluorescent protein (GFP):DspA/E fusion indicated that the fusion protein could only be detected in a few cells per seedling, suggesting the degradation or absence of accumulation of DspA/E in plant cells. Consistently, we found that DspA/E repressed plant protein synthesis when injected by E. amylovora or when expressed in transgenic plants. Thus, we conclude that DspA/E is toxic to A. thaliana: it promotes modifications, among which the repression of protein synthesis could be determinant in the facilitation of necrosis and bacterial growth. PMID:23634775

  16. Influence of phenolic compounds of Kangra tea [Camellia sinensis (L O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas

    Directory of Open Access Journals (Sweden)

    Aditi Sourabh

    2013-09-01

    Full Text Available Phenolic compounds of nutraceutical importance viz., catechins (C, (--epicatechin (EC, (--epigallocatechin (EGC, (--epigallocatechin-3-gallate (EGCG and (--epicatechin-3-gallate (ECG were estimated in fresh green tea shoots of Camellia sinensis (L O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839, Pseudomonas aeruginosa (MTCC-741, Bacillus cereus (MTCC-1272, Staphylococcus aureus (MTCC-96 and Escherichia coli (MTCC-443, and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443 but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.

  17. Nitric Oxide in the Offensive Strategy of Fungal and Oomycete Plant Pathogens

    Science.gov (United States)

    Arasimowicz-Jelonek, Magdalena; Floryszak-Wieczorek, Jolanta

    2016-01-01

    In the course of evolutionary changes pathogens have developed many invasion strategies, to which the host organisms responded with a broad range of defense reactions involving endogenous signaling molecules, such as nitric oxide (NO). There is evidence that pathogenic microorganisms, including two most important groups of eukaryotic plant pathogens, also acquired the ability to synthesize NO via non-unequivocally defined oxidative and/or reductive routes. Although the both kingdoms Chromista and Fungi are remarkably diverse, the experimental data clearly indicate that pathogen-derived NO is an important regulatory molecule controlling not only developmental processes, but also pathogen virulence and its survival in the host. An active control of mitigation or aggravation of nitrosative stress within host cells seems to be a key determinant for the successful invasion of plant pathogens representing different lifestyles and an effective mode of dispersion in various environmental niches. PMID:26973690

  18. Validation of real-time PCR assays for bioforensic detection of model plant pathogens.

    Science.gov (United States)

    James, Mindy; Blagden, Trenna; Moncrief, Ian; Burans, James P; Schneider, Katherine; Fletcher, Jacqueline

    2014-03-01

    The U.S. agricultural sector is vulnerable to intentionally introduced microbial threats because of its wide and open distribution and economic importance. To investigate such events, forensically valid assays for plant pathogen detection are needed. In this work, real-time PCR assays were developed for three model plant pathogens: Pseudomonas syringae pathovar tomato, Xylella fastidiosa, and Wheat streak mosaic virus. Validation included determination of the linearity and range, limit of detection, sensitivity, specificity, and exclusivity of each assay. Additionally, positive control plasmids, distinguishable from native signature by restriction enzyme digestion, were developed to support forensic application of the assays. Each assay displayed linear amplification of target nucleic acid, detected 100 fg or less of target nucleic acid, and was specific to its target pathogen. Results obtained with these model pathogens provide the framework for development and validation of similar assays for other plant pathogens of high consequence. PMID:24261870

  19. Terrific Protein Traffic: The Mystery of Effector Protein Delivery by Filamentous Plant Pathogens

    OpenAIRE

    Panstruga, Ralph; Dodds, Peter N.

    2009-01-01

    Many biotrophic fungal and oomycete plant pathogens deliver effector proteins directly into host cells during infection. Recent advances are revealing the extensive effector repertoires of these pathogens and are beginning to shed light on how they manipulate host cells to establish a parasitic relationship. Surprisingly, oomycete effectors seem to share a common uptake system with those from the human malaria pathogen. The current explosion of information is opening new research avenues in m...

  20. Combinations of Biocontrol Agents for Management of Plant-Parasitic Nematodes and Soilborne Plant-Pathogenic Fungi

    OpenAIRE

    Meyer, Susan L. F.; Roberts, Daniel P.

    2002-01-01

    Numerous microbes are antagonistic to plant-parasitic nematodes and soilborne plant-pathogenic fungi, but few of these organisms are commercially available for management of these pathogens. Inconsistent performance of applied biocontrol agents has proven to be a primary obstacle to the development of successful commercial products. One of the strategies for overcoming inconsistent performance is to combine the disease-suppressive activity of two (or more) beneficial microbes in a biocontrol ...

  1. Differential response of tomato genotypes to Xanthomonas-specific pathogen-associated molecular patterns and correlation with bacterial spot (Xanthomonas perforans) resistance.

    Science.gov (United States)

    Bhattarai, Krishna; Louws, Frank J; Williamson, John D; Panthee, Dilip R

    2016-01-01

    Plants depend on innate immune responses to retard the initial spread of pathogens entering through stomata, hydathodes or injuries. These responses are triggered by conserved patterns in pathogen-encoded molecules known as pathogen-associated molecular patterns (PAMPs). Production of reactive oxygen species (ROS) is one of the first responses, and the resulting 'oxidative burst' is considered to be a first line of defense. In this study, we conducted association analyses between ROS production and bacterial spot (BS; Xanthomonas spp.) resistance in 63 genotypes of tomato (Solanum lycopersicum L.). A luminol-based assay was performed on leaf tissues that had been treated with a flagellin 22 (flg22), flagellin 28 and a Xanthomonas-specific flg22 (flg22-Xac) peptide, to measure PAMP-induced ROS production in each genotype. These genotypes were also assessed for BS disease response by inoculation with Xanthomonas perforans, race T4. Although there was no consistent relationship between peptides used and host response to the BS, there was a significant negative correlation (r=-0.25, P<0.05) between foliar disease severity and ROS production, when flg22-Xac was used. This response could potentially be used to identify the Xanthomonas-specific PRR allele in tomato, and eventually PAMP-triggered immunity loci could be mapped in a segregating population. This has potential significance in tomato improvement. PMID:27555919

  2. ANTIBACTERIAL ACTIVITY OF THREE MEDICINAL PLANTS OF KUMAUN HIMALAYA AGAINST SOME PATHOGENIC BACTERIA

    OpenAIRE

    Sati, S. C.; POONAM TAKULI; Kumar, P.; K. KHULBE

    2015-01-01

    The antibacterial property of methanol, ethanol and hexane extracts of Berberis aristata, Chenopodium ambrosioides and Tinospora cordifolia grown in Kumaun Himalayan were investigated against some pathogenic gram positive and gram negative bacterial strains (Bacillus subtilis, Agrobacterium tumefaciens, Escherichia coli, Xanthomonas phaseoli and Erwinia chrysanthemi) using disc diffusion method. Methanol extract of B. aristata was found with highest inhibitory activity against E. chrysanth...

  3. Anti-bacterial effects of the essential oil of Teucrium polium L. on human pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Mohammad Mohammad

    2013-09-01

    Results: The total oil content of Teucrium polium plant was 0.75%. Twenty eight compounds were identified in the essential oil that included 99.75% of the total oil. The major components were α-pinene (12.52%, Linalool (10.63% and Caryophyllene oxide (9.69%. For study of antimicrobial activity of the oil sample, the essential oil was tested against 9 bacteria by disc diffusion method. The antimicrobial effects of this essential oil was determined against three Gram positive bacteria Staphylococcus areous (PTCC 1431, Staphylococcus epidermidis (PTCC 1436, Streptococcus faecalis (PTCC 1237; as well as six Gram negative bacteria Pseudomonas aeroginosa (PTCC 11430, Shigella flexneri (PTCC 1716, Kellebsiella pneuomonae(PTCC=1053, Salmonella typhi (PTCC=1609, Serratia marcescens (PTCC 1187 and Escherichia coli (PTCC 1533. The antimicrobial effects of this essential oil on the Gram positive bacteria ( Staphylococcus aureus and Staphylococcus epidermidis and on all the Gram negative bacteria tested was much higher than those observed by tetracycline. Conclusions: The results showed the essential oil of Teucrium polium had strong anti-bacterial effects. The relatively high contents of α-pinene and Linalool in the essential oil may be the cause of its potential medicinal effects

  4. Finding immune gene expression differences induced by marine bacterial pathogens in the Deep-sea hydrothermal vent mussel Bathymodiolus azoricus

    Science.gov (United States)

    Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.

    2013-11-01

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus lives in a natural environment characterised by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea vent biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in vent animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio bacteria. Flavobacterium suspensions were also used as a non-pathogenic bacterium. Gene expression analyses were carried out using gill samples from infected animals by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h to 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the bacterium inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly evident for proteins of 18-20 KDa molecular mass, where most dissimilarity was found. Multivariate analyses demonstrated that immune genes, as well as experimental

  5. Arabidopsis and Brachypodium distachyon transgenic plants expressing Aspergillus nidulans acetylesterases have decreased degree of polysaccharide acetylation and increased resistance to pathogens.

    Science.gov (United States)

    Pogorelko, Gennady; Lionetti, Vincenzo; Fursova, Oksana; Sundaram, Raman M; Qi, Mingsheng; Whitham, Steven A; Bogdanove, Adam J; Bellincampi, Daniela; Zabotina, Olga A

    2013-05-01

    The plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. Modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. The plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. In this study, we examined the effect of perturbing cell wall acetylation by making transgenic Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon) plants expressing hemicellulose- and pectin-specific fungal acetylesterases. All transgenic plants carried highly expressed active Aspergillus nidulans acetylesterases localized to the apoplast and had significant reduction of cell wall acetylation compared with wild-type plants. Partial deacetylation of polysaccharides caused compensatory up-regulation of three known acetyltransferases and increased polysaccharide accessibility to glycosyl hydrolases. Transgenic plants showed increased resistance to the fungal pathogens Botrytis cinerea and Bipolaris sorokiniana but not to the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. These results demonstrate a role, in both monocot and dicot plants, of hemicellulose and pectin acetylation in plant defense against fungal pathogens. PMID:23463782

  6. Foliar endophytic fungi as potential protectors from pathogens in myrmecophytic Acacia plants.

    Science.gov (United States)

    González-Teuber, Marcia; Jiménez-Alemán, Guillermo H; Boland, Wilhelm

    2014-10-01

    In defensive ant-plant interactions myrmecophytic plants express reduced chemical defense in their leaves to protect themselves from pathogens, and it seems that mutualistic partners are required to make up for this lack of defensive function. Previously, we reported that mutualistic ants confer plants of Acacia hindsii protection from pathogens, and that the protection is given by the ant-associated bacteria. Here, we examined whether foliar endophytic fungi may potentially act as a new partner, in addition to mutualistic ants and their bacteria inhabitants, involved in the protection from pathogens in myrmecophytic Acacia plants. Fungal endophytes were isolated from the asymptomatic leaves of A. hindsii plants for further molecular identification of 18S rRNA gene. Inhibitory effects of fungal endophytes were tested against Pseudomonas plant pathogens. Our findings support a potential role of fungal endophytes in pathogen the protection mechanisms against pathogens in myrmecophytic plants and provide the evidence of novel fungal endophytes capable of biosynthesizing bioactive metabolites. PMID:26843901

  7. A domain-centric analysis of oomycete plant pathogen genomes reveals unique protein organization

    NARCIS (Netherlands)

    Seidl, M.F.; Ackerveken, van den G.; Govers, F.; Snel, B.

    2011-01-01

    Oomycetes comprise a diverse group of organisms that morphologically resemble fungi but belong to the stramenopile lineage within the supergroup of chromalveolates. Recent studies have shown that plant pathogenic oomycetes have expanded gene families that are possibly linked to their pathogenic life

  8. Antifungal potential of marine sponge extract against plant and fish pathogenic fungi

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi; Ravichandran, S.; Ribeiro, M.; Ciavatta, M.L.

    -lyophilized squid mantle, 30 mg alginate and 30 mg purified sea sand (granular size 0.1- 0.3 mm). The mixture was homogenized using a mortar and pestle. The solvent was evaporated and permitted food red color dissolved in a Sr. No. Fungal PathogensPlant pathogens...

  9. N-Acyl Homoserine Lactones in Diverse Pectobacterium and Dickeya Plant Pathogens: Diversity, Abundance, and Involvement in Virulence

    Directory of Open Access Journals (Sweden)

    Denis Faure

    2012-03-01

    Full Text Available Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-L-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens.

  10. Evaluation of reference genes for real-time RT-PCR expression studies in the plant pathogen Pectobacterium atrosepticum

    Directory of Open Access Journals (Sweden)

    Toth Ian K

    2007-09-01

    Full Text Available Abstract Background Real-time RT-PCR has become a powerful technique to monitor low-abundance mRNA expression and is a useful tool when examining bacterial gene expression inside infected host tissues. However, correct evaluation of data requires accurate and reliable normalisation against internal standards. Thus, the identification of reference genes whose expression does not change during the course of the experiment is of paramount importance. Here, we present a study where manipulation of cultural growth conditions and in planta experiments have been used to validate the expression stability of reference gene candidates for the plant pathogen Pectobacterium atrosepticum, belonging to the family Enterobacteriaceae. Results Of twelve reference gene candidates tested, four proved to be stably expressed both in six different cultural growth conditions and in planta. Two of these genes (recA and ffh, encoding recombinase A and signal recognition particle protein, respectively, proved to be the most stable set of reference genes under the experimental conditions used. In addition, genes proC and gyrA, encoding pyrroline-5-carboxylate reductase and DNA gyrase, respectively, also displayed relatively stable mRNA expression levels. Conclusion Based on these results, we suggest recA and ffh as suitable candidates for accurate normalisation of real-time RT-PCR data for experiments investigating the plant pathogen P. atrosepticum and potentially other related pathogens.

  11. Evaluation of reference genes for real-time RT-PCR expression studies in the plant pathogen Pectobacterium atrosepticum

    Science.gov (United States)

    Takle, Gunnhild W; Toth, Ian K; Brurberg, May B

    2007-01-01

    Background Real-time RT-PCR has become a powerful technique to monitor low-abundance mRNA expression and is a useful tool when examining bacterial gene expression inside infected host tissues. However, correct evaluation of data requires accurate and reliable normalisation against internal standards. Thus, the identification of reference genes whose expression does not change during the course of the experiment is of paramount importance. Here, we present a study where manipulation of cultural growth conditions and in planta experiments have been used to validate the expression stability of reference gene candidates for the plant pathogen Pectobacterium atrosepticum, belonging to the family Enterobacteriaceae. Results Of twelve reference gene candidates tested, four proved to be stably expressed both in six different cultural growth conditions and in planta. Two of these genes (recA and ffh), encoding recombinase A and signal recognition particle protein, respectively, proved to be the most stable set of reference genes under the experimental conditions used. In addition, genes proC and gyrA, encoding pyrroline-5-carboxylate reductase and DNA gyrase, respectively, also displayed relatively stable mRNA expression levels. Conclusion Based on these results, we suggest recA and ffh as suitable candidates for accurate normalisation of real-time RT-PCR data for experiments investigating the plant pathogen P. atrosepticum and potentially other related pathogens. PMID:17888160

  12. Effects of volatile organic compounds produced by Bacillus amyloliquefaciens on the growth and virulence traits of tomato bacterial wilt pathogen Ralstonia solanacearum.

    Science.gov (United States)

    Raza, Waseem; Wang, Jichen; Wu, Yuncheng; Ling, Ning; Wei, Zhong; Huang, Qiwei; Shen, Qirong

    2016-09-01

    The production of volatile organic compounds (VOCs) by microbes is an important characteristic for their selection as biocontrol agents against plant pathogens. In this study, we identified the VOCs produced by the biocontrol strain Bacillus amyloliquefaciens T-5 and evaluated their impact on the growth and virulence traits of tomato bacterial wilt pathogen Ralstonia solanacearum. The results showed that the VOCs of strain T-5 significantly inhibited the growth of R. solanacearum in agar medium and in soil. In addition, VOCs significantly inhibited the motility traits, root colonization, biofilm formation, and production of antioxidant enzymes and exopolysaccharides by R. solanacearum. However, no effect of VOCs on the production of hydrolytic enzymes by R. solanacearum was observed. The strain T-5 produced VOCs, including benzenes, ketones, aldehydes, alkanes, acids, and one furan and naphthalene compound; among those, 13 VOCs showed 1-10 % antibacterial activity against R. solanacearum in their produced amounts by T-5; however, the consortium of all VOCs produced on agar medium, in sterilized soil, and in natural soil showed 75, 62, and 85 % growth inhibition of R. solanacearum, respectively. The real-time PCR analysis further confirmed the results when the expression of different virulence- and metabolism-related genes in R. solanacearum cells was decreased after exposure to the VOCs of strain T-5. The results of this study clearly revealed the significance of VOCs in the control of plant pathogens. This information would help to better comprehend the microbial interactions mediated by VOCs in nature and to develop safer strategies to control plant disease. PMID:27183998

  13. Age-related presence of selected viral and bacterial pathogens in paraffin-embedded lung samples of dogs with pneumonia.

    Science.gov (United States)

    Wöhrer, Daniela; Spergser, Joachim; Bagrinovschi, Gabriela; Möstl, Karin; Weissenböck, Herbert

    2016-03-01

    The aim of this retrospective study was to detect selected pathogens in pneumonic lung tissue of dogs of different age groups by immunohistochemistry (IHC), in situ hybridisation (ISH) or polymerase chain reaction (PCR) in order to get information about their involvement in pneumonia formation. In archived formalin-fixed and paraffin wax-embedded lung samples from 68 cases with the clinical and histologic diagnosis of pneumonia the histological pattern of pneumonia was re-evaluated and the samples were further investigated for the following infectious agents: canine distemper virus (CDV), canine adenovirus type 2 (CAV-2), canine respiratory coronavirus (CRCoV), Bordetella (B.) bronchiseptica, Pasteurella (P.) multocida, Mycoplasma spp., and Pneumocystis spp. In 47.1% of the samples at least one of the featured respiratory pathogens was detected. In 31.3% of these positive samples more than one pathogen could be found. The correct detection of CDV had been achieved in ten out of eleven positive cases (90.9%) upon initial investigation, but the presence of bacterial pathogens, like B. bronchiseptica (10 cases) and P. multocida (17 cases) had been missed in all but one case. While CDV and CRCoV infections were exclusively found in dogs younger than one year, the vast majority of infections with P. multocida and B. bronchiseptica were both common either in dogs younger than 4 months or older than one year. Thus, this retrospective approach yielded valuable data on the presence, absence and prevalence of certain respiratory pathogens in dogs with pneumonia. PMID:26919147

  14. Prevalence of swine viral and bacterial pathogens in rodents and stray cats captured around pig farms in Korea.

    Science.gov (United States)

    Truong, Quang Lam; Seo, Tae Won; Yoon, Byung-Il; Kim, Hyeon-Cheol; Han, Jeong Hee; Hahn, Tae-Wook

    2013-12-30

    In 2008, 102 rodents and 24 stray cats from the areas around 9 pig farms in northeast South Korea were used to determine the prevalence of the following selected swine pathogens: ten viral pathogens [porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), rotavirus, classical swine fever virus (CSFV), porcine circovirus type 2 (PCV2), encephalomyocarditis virus (EMCV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus (PPV), pseudorabies virus (PRV) and Japanese encephalitis virus (JEV)] and four bacterial pathogens (Brucella, Leptospira, Salmonella and Lawsonia intracellularis). In total, 1,260 tissue samples from 102 rodents and 24 stray cats were examined by specific PCR and RT-PCR assays, including tissue samples of the brain, tonsils, lungs, heart, liver, kidneys, spleen, small intestine, large intestine and mesenteric lymph nodes. The percentages of PCR-positive rodents for the porcine pathogens were as follows: 63.7% for Leptospira, 39.2% for Brucella, 6.8% for Salmonella, 15.7% for L. intracellularis, 14.7% for PCV2 and 3.9% for EMCV. The percentages of PCR-positive stray cats for the swine pathogens were as follows: 62.5% for Leptospira, 25% for Brucella, 12.5% for Salmonella, 12.5% for L. intracellularis and 4.2% for PEDV. These results may be helpful for developing control measures to prevent the spread of infectious diseases of pigs. PMID:23892461

  15. Phage–host interplay: examples from tailed phages and Gram-negative bacterial pathogens

    OpenAIRE

    Chaturongakul, Soraya; Ounjai, Puey

    2014-01-01

    Complex interactions between bacteriophages and their bacterial hosts play significant roles in shaping the structure of environmental microbial communities, not only by genetic transduction but also by modification of bacterial gene expression patterns. Survival of phages solely depends on their ability to infect their bacterial hosts, most importantly during phage entry. Successful dynamic adaptation of bacteriophages when facing selective pressures, such as host adaptation and resistance, ...

  16. Phage-host interplay: examples from tailed phages and Gram-negative bacterial pathogens

    OpenAIRE

    PueyOunjai; SorayaChaturongakul

    2014-01-01

    Complex interactions between bacteriophages and their bacterial hosts play significant roles in shaping the structure of environmental microbial communities, not only by genetic transduction but also by modification of bacterial gene expression patterns. Survival of phages solely depends on their ability to infect their bacterial hosts, most importantly during phage entry. Successful dynamic adaptation of bacteriophages when facing selective pressures, such as host adaptation and resistance, ...

  17. Plant-by-plant variations of bacterial communities associated with leaves of the nickel hyperaccumulator Alyssum bertolonii Desv.

    Science.gov (United States)

    Mengoni, Alessio; Pini, Francesco; Huang, Li-Nan; Shu, Wen-Sheng; Bazzicalupo, Marco

    2009-10-01

    Bacteria associated with tissues of metal-hyperaccumulating plants are of great interest due to the multiple roles they may play with respect to plant growth and resistance to heavy metals. The variability of bacterial communities associated with plant tissues of three populations of Alyssum bertolonii, a Ni hyperaccumulator endemic of serpentine outcrops of Central Italy, was investigated. Terminal-restriction fragment length polymorphism (T-RFLP) analysis of bacterial 16S rRNA genes was applied to DNA extracted from leaf tissues of 30 individual plants from three geographically separated serpentine outcrops. Moreover, T-RFLP fingerprinting was also performed on DNA extracted from the same soils from which the plants were collected. Fifty-nine unique terminal-restriction fragments (TRFs) were identified, with more than half of the taxonomically interpreted TRFs assigned to Alpha- and Gamma-Proteobacteria and Clostridia. Data were then used to define the extent of variation of bacterial communities due to single plants or to plant populations. Results indicated a very high plant-by-plant variation of leaf-associated community (more than 93% of total variance observed). However, a core (numerically small) of plant-specific TRFs was found. This work demonstrates that plant-associated bacterial communities represent a large reservoir of biodiversity and that the high variability existing between plants, even from the same population, should be taken into account in future studies on association between bacteria and metal-hyperaccumulating plants. PMID:19479304

  18. Amazonian dark Earth and plant species from the Amazon region contribute to shape rhizosphere bacterial communities.

    Science.gov (United States)

    Barbosa Lima, Amanda; Cannavan, Fabiana Souza; Navarrete, Acacio Aparecido; Teixeira, Wenceslau Geraldes; Kuramae, Eiko Eurya; Tsai, Siu Mui

    2015-05-01

    Amazonian Dark Earths (ADE) or Terra Preta de Índio formed in the past by pre-Columbian populations are highly sustained fertile soils supported by microbial communities that differ from those extant in adjacent soils. These soils are found in the Amazon region and are considered as a model soil when compared to the surrounding and background soils. The aim of this study was to assess the effects of ADE and its surrounding soil on the rhizosphere bacterial communities of two leguminous plant species that frequently occur in the Amazon region in forest sites (Mimosa debilis) and open areas (Senna alata). Bacterial community structure was evaluated using terminal restriction fragment length polymorphism (T-RFLP) and bacterial community composition by V4 16S rRNA gene region pyrosequencing. T-RFLP analysis showed effect of soil types and plant species on rhizosphere bacterial community structure. Differential abundance of bacterial phyla, such as Acidobacteria, Actinobacteria, Verrucomicrobia, and Firmicutes, revealed that soil type contributes to shape the bacterial communities. Furthermore, bacterial phyla such as Firmicutes and Nitrospira were mostly influenced by plant species. Plant roots influenced several soil chemical properties, especially when plants were grown in ADE. These results showed that differences observed in rhizosphere bacterial community structure and composition can be influenced by plant species and soil fertility due to variation in soil attributes. PMID:25103911

  19. Emerging trends in molecular interactions between plants and the broad host range fungal pathogens Botrytis cinerea and Sclerotinia sclerotiorum

    OpenAIRE

    Mbengue, Malick; Navaud, Olivier; Peyraud, Rémi; Barascud, Marielle; Badet, Thomas; Vincent, Rémy; Barbacci, Adelin; Raffaele, Sylvain

    2016-01-01

    Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is know...

  20. Metabolic Environments and Genomic Features Associated with Pathogenic and Mutualistic Interactions between Bacteria and Plants is accepted for publication in MPMI

    Energy Technology Data Exchange (ETDEWEB)

    Karpinets, Tatiana V [ORNL; Park, Byung H [ORNL; Syed, Mustafa H [ORNL; Klotz, Martin G [University of North Carolina, Charlotte; Uberbacher, Edward C [ORNL

    2014-01-01

    Most bacterial symbionts of plants are phenotypically characterized by their parasitic or matualistic relationship with the host; however, the genomic characteristics that likely discriminate mutualistic symbionts from pathogens of plants are poorly understood. This study comparatively analyzed the genomes of 54 plant-symbiontic bacteria, 27 mutualists and 27 pathogens, to discover genomic determinants of their parasitic and mutualistic nature in terms of protein family domains, KEGG orthologous groups, metabolic pathways and families of carbohydrate-active enzymes (CAZymes). We further used all bacteria with sequenced genomesl, published microarrays and transcriptomics experimental datasets, and literature to validate and to explore results of the comparison. The analysis revealed that genomes of mutualists are larger in size and higher in GC content and encode greater molecular, functional and metabolic diversity than the investigated genomes of pathogens. This enriched molecular and functional enzyme diversity included constructive biosynthetic signatures of CAZymes and metabolic pathways in genomes of mutualists compared with catabolic signatures dominant in the genomes of pathogens. Another discriminative characteristic of mutualists is the co-occurence of gene clusters required for the expression and function of nitrogenase and RuBisCO. Analysis of previously published experimental data indicate that nitrogen-fixing mutualists may employ Rubisco to fix CO2 not in the canonical Calvin-Benson-Basham cycle but in a novel metabolic pathway, here called Rubisco-based glycolysis , to increase efficiency of sugar utilization during the symbiosis with plants. An important discriminative characteristic of plant pathogenic bacteria is two groups of genes likely encoding effector proteins involved in host invasion and a genomic locus encoding a putative secretion system that includes a DUF1525 domain protein conserved in pathogens of plants and of other organisms. The

  1. Development of recombinant antibody technology for application in plant pathogen diagnosis

    OpenAIRE

    Griep, R.A.

    1999-01-01

    This thesis describes the applicability of the novel phage display technique to select plant-pathogen-specific monoclonal antibodies (MAbs) from combinatorial antibody libraries. The retrieved MAbs are so specific that they can be used as diagnostic tools in sensitive immunoassays for the detection and identification of plant pathogens. Testing results, obtained from laboratories that have applied these recombinant MAbs, are discussed in this conclusive chapter.BackgroundIn the last decades, ...

  2. The homeodomain transcription factor Ste12: Connecting fungal MAPK signalling to plant pathogenicity

    OpenAIRE

    Rispail, Nicolas; Pietro, A. D.

    2010-01-01

    A conserved mitogen-activated protein kinase (MAPK) cascade orthologous to the mating/filamentation MAPK pathway in yeast is required for fungal pathogenicity on plants. One of the key targets of this signaling pathway is the homeodomain transcription factor Ste12. Mutational analysis of ste12 orthologues in a variety of plant pathogenic fungi suggests that Ste12 functions as a master regulator of invasive growth. In this mini-review we highlight recent progress in understanding the role of S...

  3. ``Black Holes" and Bacterial Pathogenicity: A Large Genomic Deletion that Enhances the Virulence of Shigella spp. and Enteroinvasive Escherichia coli

    Science.gov (United States)

    Maurelli, Anthony T.; Fernandez, Reinaldo E.; Bloch, Craig A.; Rode, Christopher K.; Fasano, Alessio

    1998-03-01

    Plasmids, bacteriophages, and pathogenicity islands are genomic additions that contribute to the evolution of bacterial pathogens. For example, Shigella spp., the causative agents of bacillary dysentery, differ from the closely related commensal Escherichia coli in the presence of a plasmid in Shigella that encodes virulence functions. However, pathogenic bacteria also may lack properties that are characteristic of nonpathogens. Lysine decarboxylate (LDC) activity is present in ≈ 90% of E. coli strains but is uniformly absent in Shigella strains. When the gene for LDC, cadA, was introduced into Shigella flexneri 2a, virulence became attenuated, and enterotoxin activity was inhibited greatly. The enterotoxin inhibitor was identified as cadaverine, a product of the reaction catalyzed by LDC. Comparison of the S. flexneri 2a and laboratory E. coli K-12 genomes in the region of cadA revealed a large deletion in Shigella. Representative strains of Shigella spp. and enteroinvasive E. coli displayed similar deletions of cadA. Our results suggest that, as Shigella spp. evolved from E. coli to become pathogens, they not only acquired virulence genes on a plasmid but also shed genes via deletions. The formation of these ``black holes,'' deletions of genes that are detrimental to a pathogenic lifestyle, provides an evolutionary pathway that enables a pathogen to enhance virulence. Furthermore, the demonstration that cadaverine can inhibit enterotoxin activity may lead to more general models about toxin activity or entry into cells and suggests an avenue for antitoxin therapy. Thus, understanding the role of black holes in pathogen evolution may yield clues to new treatments of infectious diseases.

  4. Rosmarinic acid is a homoserine lactone mimic produced by plants that activates a bacterial quorum-sensing regulator.

    Science.gov (United States)

    Corral-Lugo, Andrés; Daddaoua, Abdelali; Ortega, Alvaro; Espinosa-Urgel, Manuel; Krell, Tino

    2016-01-01

    Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a plant-derived compound that functioned as an HSL mimic. In vitro assays showed that rosmarinic acid bound to the quorum-sensing regulator RhlR of Pseudomonas aeruginosa PAO1 and competed with the bacterial ligand N-butanoyl-homoserine lactone (C4-HSL). Furthermore, rosmarinic acid stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL. In P. aeruginosa, rosmarinic acid induced quorum sensing-dependent gene expression and increased biofilm formation and the production of the virulence factors pyocyanin and elastase. Because P. aeruginosa PAO1 infection induces rosmarinic acid secretion from plant roots, our results indicate that rosmarinic acid secretion is a plant defense mechanism to stimulate a premature quorum-sensing response. P. aeruginosa is a ubiquitous pathogen that infects plants and animals; therefore, identification of rosmarinic acid as an inducer of premature quorum-sensing responses may be useful in agriculture and inform human therapeutic strategies. PMID:26732761

  5. Common strategies for antigenic variation by bacterial, fungal and protozoan pathogens

    OpenAIRE

    Deitsch, Kirk W.; Lukehart, Sheila A.; Stringer, James R.

    2009-01-01

    The complex relationships between infectious organisms and their hosts often reflect the continuing struggle of the pathogen to proliferate and spread to new hosts, and the need of the infected individual to control and potentially eradicate the infecting population. In the case of mammals and the pathogens that infect them, a veritable “arms race” has ensued. A highly adapted immune system has evolved to control the proliferation of infectious organisms and the pathogens have developed corre...

  6. Diet and Environment Shape Fecal Bacterial Microbiota Composition and Enteric Pathogen Load of Grizzly Bears

    OpenAIRE

    Schwab, Clarissa; Cristescu, Bogdan; Northrup, Joseph M.; Stenhouse, Gordon B.; Gänzle, Michael

    2011-01-01

    Background Diet and environment impact the composition of mammalian intestinal microbiota; dietary or health disturbances trigger alterations in intestinal microbiota composition and render the host susceptible to enteric pathogens. To date no long term monitoring data exist on the fecal microbiota and pathogen load of carnivores either in natural environments or in captivity. This study investigates fecal microbiota composition and the presence of pathogenic Escherichia coli and toxigenic cl...

  7. Isolation and Characterization of Chitinolytic Bacteria and Their Potential to Inhibit Plant Pathogenic Fungi

    Directory of Open Access Journals (Sweden)

    DWI SURYANTO

    2011-09-01

    Full Text Available A study on the isolation and characterization of chitinolytic bacteria and their potential to inhibit plant pathogenic fungi has been done. The bacteria were isolated from the soil of Karo, Langkat, and Bangka, Sumatra. Ganoderma boninense, Fusarium oxysporum, and Penicillium citrinum of the stock cultures in Laboratory of Microbiology Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara were used for growth inhibition assay by the isolated bacteria. KR05 and LK08 shared similar morphological and physiological characters; like wise, KR07 shared property similarities with BK08. All bacterial isolates inhibited the growth of G. boninense F. oxysporum , and P. citrinum at a different extent. LK08 showed the highest inhibition rate followed by BK07 and BK09. However, P. citrinum was inhibited more by BK07 and BK09. The crude enzyme preparation of the latter isolate exhibited the highest chitinase activity. The result suggested that their swarming activity seemed to contributed to inhibition of fungal growth.

  8. Comparison of Bacterial Community Structures in the Rhizoplane of Tomato Plants Grown in Soils Suppressive and Conducive towards Bacterial Wilt

    OpenAIRE

    Shiomi, Yoshitaka; Nishiyama, Masaya; Onizuka, Tomoko; Marumoto, Takuya

    1999-01-01

    It has been reported that the growth of Ralstonia solanacearum is suppressed at the rhizoplane of tomato plants and that tomato bacterial wilt is suppressed in plants grown in a soil (Mutsumi) in Japan. To evaluate the biological factors contributing to the suppressiveness of the soil in three treated Mutsumi soils (chloroform fumigated soil; autoclaved soil mixed with intact Mutsumi soil; and autoclaved soil mixed with intact, wilt-conducive Yamadai soil) infested with R. solanacearum, we bi...

  9. Nasopharyngeal vs. adenoid cultures in children undergoing adenoidectomy: prevalence of bacterial pathogens, their interactions and risk factors.

    Science.gov (United States)

    Korona-Glowniak, I; Niedzielski, A; Kosikowska, U; Grzegorczyk, A; Malm, A

    2015-03-01

    Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus colonization of the adenoids and nasopharynx in 103 preschool children who underwent adenoidectomy for recurrent upper respiratory tract infections was examined. Bacterial interactions and risk factors for bacterial colonization of the nasopharynx and adenoids, separately, were analysed statistically. The prevalence of simultaneous isolation from both anatomical sites was 45·6% for S. pneumoniae, 29·1% for H. influenzae, 15·5% for M. catarrhalis and 18·4% for S. aureus. Three pathogens were significantly more frequent together from adenoid samples; nasopharyngeal swabs more often yielded a single organism, but without statistical significance. M. catarrhalis and S. aureus significantly more frequently co-existed with S. pneumoniae and H. influenzae than with each other and a positive association of S. pneumoniae and H. influenzae in adenoid samples was evident. Several differences between risk factors for nasopharyngeal and adenoid colonization by the individual pathogens were observed. We conclude that the adenoids and nasopharynx appear to differ substantially in colonization by pathogenic microbes but occurrence of H. influenzae and S. pneumoniae in the nasopharynx could be predictive of upper respiratory tract infections. PMID:25703401

  10. Novel components of leaf bacterial communities of field-grown tomato plants and their potential for plant growth promotion and biocontrol of tomato diseases.

    Science.gov (United States)

    Romero, Fernando M; Marina, María; Pieckenstain, Fernando L

    2016-04-01

    This work aimed to characterize potentially endophytic culturable bacteria from leaves of cultivated tomato and analyze their potential for growth promotion and biocontrol of diseases caused by Botrytis cinerea and Pseudomonas syringae. Bacteria were obtained from inner tissues of surface-disinfected tomato leaves of field-grown plants. Analysis of 16S rRNA gene sequences identified bacterial isolates related to Exiguobacterium aurantiacum (isolates BT3 and MT8), Exiguobacterium spp. (isolate GT4), Staphylococcus xylosus (isolate BT5), Pantoea eucalypti (isolate NT6), Bacillus methylotrophicus (isolate MT3), Pseudomonas veronii (isolates BT4 and NT2), Pseudomonas rhodesiae (isolate BT2) and Pseudomonas cichorii (isolate NT3). After seed inoculation, BT2, BT4, MT3, MT8, NT2 and NT6 were re-isolated from leaf extracts. NT2, BT2, MT3 and NT6 inhibited growth of Botrytis cinerea and Pseudomonas syringae pv. tomato in vitro, produced antimicrobial compounds and reduced leaf damage caused by B. cinerea. Some of these isolates also promoted growth of tomato plants, produced siderophores, the auxin indole-3-acetic and solubilized inorganic phosphate. Thus, bacterial communities of leaves from field-grown tomato plants were found to harbor potentially endophytic culturable beneficial bacteria capable of antagonizing pathogenic microorganisms and promoting plant growth, which could be used as biological control agents and biofertilizers/biostimulators for promotion of tomato plant growth. PMID:26654914

  11. Bioactive Potential of Peppermint Extract Against Some Human Bacterial and Fungal Pathogens

    OpenAIRE

    Farzaei; Azizi,, F; Arji; Rostami

    2015-01-01

    Background Bacterial and fungal infections are an emerging public health concern, especially in the context of nosocomial infections. This study discusses the use of peppermint (Mentha piperita L.) methanolic extract against bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus and fungal species such as Trichophyton mentagrophytes, Trichophyton verrucosum, and Candida albicans. Object...

  12. Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions

    Directory of Open Access Journals (Sweden)

    Horst Vierheilig

    2007-07-01

    Full Text Available Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF, are provided.

  13. Genetic and Epigenetic Effects of Plant-Pathogen Interactions: An Evolutionary Perspective

    Institute of Scientific and Technical Information of China (English)

    Alex Boyko; Igor Kovalchuk

    2011-01-01

    Recent reports suggest that exposure to stress is capable of influencing the frequency and pattern of inherited changes in various parts of the genome.In this review,we will discuss the influence of viral pathogens on somatic and meiotic genome stability of Nicotiana tabacum and Arabidopsis thaliana.Plants infected with a compatible pathogen generate a systemic recombination signal that precedes the spread of pathogens and results in changes in the somatic and meiotic recombination frequency.The progeny of infected plants exhibit changes in global and locusspecific DNA methylation patterns,genomic rearrangements at transgenic reporter loci and resistance gene-like-loci,and even tolerance to pathogen infection and abiotic stress.Here,we will discuss the contribution of environmental stresses to genome evolution and will focus on the role of heritable epigenetic changes in response to pathogen infection.

  14. Conservation of plasmids among plant-pathogenic Pseudomonas syringae isolates of diverse origins.

    Science.gov (United States)

    von Bodman, S B; Shaw, P D

    1987-05-01

    Thirty isolates of Pseudomonas syringae pv. tabaci, pv. angulata (pathogens on tobacco), pv. coronafaciens, and pv. striafaciens (pathogens on oats) were examined for plasmid DNAs. The strains were obtained from plants throughout the world, some over 50 years ago. Of the 22 tobacco pathogens, 16 contain predominantly one type of plasmid, the pJP27.00 type. The remaining six tobacco-specific strains do not harbor detectable plasmids. The oat pathogens contain one, two, or three plasmids. DNA homology studies indicate that the plasmid DNAs are highly conserved. More importantly, the plasmids harbored by strains isolated from one host plant are conserved most stringently; e.g., the plasmids from the tobacco pathogens are, with one exception, indistinguishable by restriction endonuclease digestion and Southern hybridization. There is also extensive homology among plasmids indigenous to the oat-specific P. syringae pv. coronafaciens and pv. striafaciens strains. PMID:3628554

  15. Genome Sequence of the Banana Pathogen Dickeya zeae Strain MS1, Which Causes Bacterial Soft Rot

    OpenAIRE

    Zhang, Jing-Xin; Lin, Bi-Run; Shen, Hui-Fang; Pu, Xiao-Ming

    2013-01-01

    We report a draft genome sequence of Dickeya zeae strain MS1, which is the causative agent of banana soft rot in China, and we show several of its specific properties compared with those of other D. zeae strains. Genome sequencing provides a tool for understanding the genomic determination of the pathogenicity and phylogeny placement of this pathogen.

  16. Draft Genome Sequence of Nocardia jinanensis, an Opportunistic Bacterial Pathogen That Causes Cellulitis

    Science.gov (United States)

    Chakrabortti, Alolika; Li, Jinming

    2016-01-01

    The draft genome sequence of Nocardia jinanensis, an opportunistic pathogen that can cause skin infections, reveals genes that may contribute to the lifestyle and pathogenicity of N. jinanensis. The genome also reveals the biosynthetic capacity of N. jinanensis in producing mycolic acids, siderophores, and other polyketide and nonribosomal peptide-derived secondary metabolites. PMID:27445366

  17. Phytoextracts-Synthesized Silver Nanoparticles Inhibit Bacterial Fish Pathogen Aeromonas hydrophila.

    Science.gov (United States)

    Mahanty, Arabinda; Mishra, Snehasish; Bosu, Ranadhir; Maurya, Uk; Netam, Surya Prakash; Sarkar, Biplab

    2013-12-01

    Fish disease is a major stumbling block towards sustainable growth of the fisheries sector. Aeromonas hydrophila, which is a major infectious aquatic pathogen is reportedly the causative agent of ulcers, fin-rot, tail-rot, hemorrhagic septicemia in fish, and has reportedly developed resistance against many of the available antibiotics. In this context, the inhibitory function of silver nanoparticles (AgNPs) against A. hydrophila was studied to evaluate its possible application in aquaculture as alternative to antibiotics. AgNPs were synthesized using the leaf extracts of subtropical plants Mangifera indica (Mango), Eucalyptus terticornis (Eucalyptus), Carica papaya (Papaya) and Musa paradisiaca (Banana). The absorbance maxima, size range and shape of the AgNPs as characterized by the UV-Vis spectroscopy, high resolution transmission electron microscopy (HR-TEM), and energy dispersive X-ray spectroscopy (EDX) were, Mangifera-442, 50-65 nm, ovular; Eucalyptus-465, 60-150 nm, oval; Carica-442, 25-40 nm, round, irregular; and Musa-454, 10-50 nm, round, irregular, respectively. Well-diffusion of these AgNPs for their antimicrobial characteristics exhibited that, the papaya leaf extract synthesized AgNPs had maximum antimicrobial activity at 153.6 μg/ml concentrations, and that from the eucalyptus leaves was least effective. As observed, the potency of the nanoparticles enhanced with the decrease in particle size, from 60-150 nm in eucalyptus to 25-40 nm in papaya. Due to its purely natural sourcing, phytosynthesized AgNPs can be applied as alternative to antibiotics and other biocides as a cost-effective and eco-friendly therapeutic agent against A. hydrophila stimulated diseases in aquatic animals. PMID:24426148

  18. Bacterial communities of two parthenogenetic aphid species cocolonizing two host plants across the Hawaiian Islands.

    Science.gov (United States)

    Jones, Ryan T; Bressan, Alberto; Greenwell, April M; Fierer, Noah

    2011-12-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants. PMID:21965398

  19. Computational models in plant-pathogen interactions: the case of Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    González Barrios Andres F

    2009-11-01

    Full Text Available Abstract Background Phytophthora infestans is a devastating oomycete pathogen of potato production worldwide. This review explores the use of computational models for studying the molecular interactions between P. infestans and one of its hosts, Solanum tuberosum. Modeling and conclusion Deterministic logistics models have been widely used to study pathogenicity mechanisms since the early 1950s, and have focused on processes at higher biological resolution levels. In recent years, owing to the availability of high throughput biological data and computational resources, interest in stochastic modeling of plant-pathogen interactions has grown. Stochastic models better reflect the behavior of biological systems. Most modern approaches to plant pathology modeling require molecular kinetics information. Unfortunately, this information is not available for many plant pathogens, including P. infestans. Boolean formalism has compensated for the lack of kinetics; this is especially the case where comparative genomics, protein-protein interactions and differential gene expression are the most common data resources.

  20. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

    DEFF Research Database (Denmark)

    Hendriksen, Rene S.; Mevius, Dik J; Schroeter, Andreas;

    2008-01-01

    Background: The project "Antibiotic resistance in bacteria of animal origin - II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003 - 2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories...... in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected. Method: Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period...... testing was conducted each year to test the accuracy of antimicrobial susceptibility testing in the participating laboratories. The data from this testing demonstrated that for the species included in the EQAS the results are comparable between countries. Results: Data from 25,241 isolates were collected...

  1. Disruption of Vector Host Preference with Plant Volatiles May Reduce Spread of Insect-Transmitted Plant Pathogens.

    Science.gov (United States)

    Martini, Xavier; Willett, Denis S; Kuhns, Emily H; Stelinski, Lukasz L

    2016-05-01

    Plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. It has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. In addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. We present a model that demonstrates how a phytophathogen (Candidatus Liberibacter asiaticus) can increase its spread by indirectly manipulating the behavior of its vector (Asian citrus psyllid, Diaphorina citri Kuwayama). The model indicates that when vectors are attracted to pathogen-infected hosts, the proportion of infected vectors increases, as well as, the proportion of infected hosts. Additionally, the peak of infected host populations occurs earlier as compared with controls. These changes in disease dynamics were more important during scenarios with higher vector mortality. Subsequently, we conducted a series of experiments to disrupt the behavior of the Asian citrus psyllid. To do so, we exposed the vector to methyl salicylate, the major compound released following host infection with the pathogen. We observed that during exposure or after pre-exposure to methyl salicylate, the host preference can be altered; indeed, the Asian citrus psyllids were unable to select infected hosts over uninfected counterparts. We suggest mechanisms to explain these interactions and potential applications of disrupting herbivore host preference with plant volatiles for sustainable management of insect vectors. PMID:27193763

  2. Perforin-2 Protects Host Cells and Mice by Restricting the Vacuole to Cytosol Transitioning of a Bacterial Pathogen.

    Science.gov (United States)

    McCormack, Ryan; Bahnan, Wael; Shrestha, Niraj; Boucher, Justin; Barreto, Marcella; Barrera, Carlos M; Dauer, Edward A; Freitag, Nancy E; Khan, Wasif N; Podack, Eckhard R; Schesser, Kurt

    2016-04-01

    The host-encoded Perforin-2 (encoded by the macrophage-expressed gene 1,Mpeg1), which possesses a pore-forming MACPF domain, reduces the viability of bacterial pathogens that reside within membrane-bound compartments. Here, it is shown that Perforin-2 also restricts the proliferation of the intracytosolic pathogenListeria monocytogenes Within a few hours of systemic infection, the massive proliferation ofL. monocytogenesinPerforin-2(-/-)mice leads to a rapid appearance of acute disease symptoms. We go on to show in culturedPerforin-2(-/-)cells that the vacuole-to-cytosol transitioning ofL. monocytogenesis greatly accelerated. Unexpectedly, we found that inPerforin-2(-/-)macrophages,Listeria-containing vacuoles quickly (≤15 min) acidify, and that this was coincident with greater virulence gene expression, likely accounting for the more rapid translocation ofL. monocytogenesto its replicative niche in the cytosol. This hypothesis was supported by our finding that aL. monocytogenesstrain expressing virulence factors at a constitutively high level replicated equally well inPerforin-2(+/+)andPerforin-2(-/-)macrophages. Our findings suggest that the protective role of Perforin-2 against listeriosis is based on it limiting the intracellular replication of the pathogen. This cellular activity of Perforin-2 may derive from it regulating the acidification ofListeria-containing vacuoles, thereby depriving the pathogen of favorable intracellular conditions that promote its virulence gene activity. PMID:26831467

  3. In Vitro Activity of Gepotidacin, a Novel Triazaacenaphthylene Bacterial Topoisomerase Inhibitor, against a Broad Spectrum of Bacterial Pathogens.

    Science.gov (United States)

    Biedenbach, D J; Bouchillon, S K; Hackel, M; Miller, L A; Scangarella-Oman, N E; Jakielaszek, C; Sahm, D F

    2016-01-01

    Gepotidacin inhibits bacterial DNA replication through a mode different from that of fluoroquinolones. Gepotidacin and comparators were tested by broth and agar dilution against clinical isolates. The in vitro activities of gepotidacin were comparable against methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) isolates (MIC90, 0.5 μg/ml). The gepotidacin MIC90s were as follows (in micrograms per milliliter) for the indicated bacteria: Streptococcus pyogenes, 0.25; Escherichia coli, 2; Moraxella catarrhalis, ≤0.06; Streptococcus pneumoniae (0.25), Haemophilus influenzae, 1; Clostridium perfringens, 0.5; and Shigella spp., 1, including levofloxacin-resistant subsets. Gepotidacin warrants further investigation for clinical development. PMID:26729499

  4. Biological activity of some bacterial isolates against soil borne pathogenic fungi

    International Nuclear Information System (INIS)

    The antagonistic activity of three bacterial isolates namely Micro bacterium terregens, Cellulosimicrobium cellulans and Bacillus amyloliquefaciens was evaluated through direct confrontation method and filtrates culture against the growth of Fusarium solani, Fusarium oxysporum, Rhizoctonia solani and Phytophthra cactorum. All bacterial isolates showed the inhibition of the mycelia growth of the isolated fungi as resulting to confrontation methods except R. solani with C. cellulans that showed no inhibitory effect and energized the low activity with B. amyloliquefaciens. Culture filtrate of different bacterial isolates after different incubation periods revealed that the highest antifungal activity between 3-10 days

  5. The evolutionary strategies of plant defenses have a dynamic impact on the adaptations and interactions of vectors and pathogens

    Institute of Scientific and Technical Information of China (English)

    Ordom Brian Huot; Punya Nachappa; Cecilia Tamborindeguy

    2013-01-01

    Plants have evolved and diversified to reduce the damages imposed by infectious pathogens and herbivorous insects.Living in a sedentary lifestyle,plants are constantly adapting to their environment.They employ various strategies to increase performance and fitness.Thus,plants developed cost-effective strategies to defend against specific insects and pathogens.Plant defense,however,imposes selective pressure on insects and pathogens.This selective pressure provides incentives for pathogens and insects to diversify and develop strategies to counter plant defense.This results in an evolutionary arms race among plants,pathogens and insects.The ever-changing adaptations and physiological alterations among these organisms make studying plant-vector-pathogen interactions a challenging and fascinating field.Studying plant defense and plant protection requires knowledge of the relationship among organisms and the adaptive strategies each organism utilize.Therefore,this review focuses on the integral parts of plant-vectorpathogen interactions in order to understand the factors that affect plant defense and disease development.The review addresses plant-vector-pathogen co-evolution,plant defense strategies,specificity of plant defenses and plant-vector-pathogen interactions.Improving the comprehension of these factors will provide a multi-dimensional perspective for the future research in pest and disease management.

  6. The effects of bacterial volatile emissions on plant abiotic stress tolerance

    OpenAIRE

    Xiao-min LIU; Zhang, Huiming

    2015-01-01

    Plant growth-promoting rhizobacteria (PGPR) are beneficial plant symbionts that have been successfully used in agriculture to increase seedling emergence, plant weight, crop yield, and disease resistance. Some PGPR strains release volatile organic compounds (VOCs) that can directly and/or indirectly mediate increases in plant biomass, disease resistance, and abiotic stress tolerance. This mini-review focuses on the enhancement of plant abiotic stress tolerance by bacterial VOCs. The review co...

  7. Nitric oxide: an effective weapon of the plant or the pathogen?

    Science.gov (United States)

    Arasimowicz-Jelonek, Magdalena; Floryszak-Wieczorek, Jolanta

    2014-05-01

    An explosion of research in plant nitric oxide (NO) biology during the last two decades has revealed that NO is a key signal involved in plant development, abiotic stress responses and plant immunity. During the course of evolutionary changes, microorganisms parasitizing plants have developed highly effective offensive strategies, in which NO also seems to be implicated. NO production has been demonstrated in several plant pathogens, including fungi, but the origin of NO seems to be as puzzling as in plants. So far, published studies have been spread over multiple species of pathogenic microorganisms in various developmental stages; however, the data clearly indicate that pathogen-derived NO is an important regulatory molecule involved not only in developmental processes, but also in pathogen virulence and its survival in the host. This review also focuses on the search for potential mechanisms by which pathogens convert NO messages into a physiological response or detoxify both endo- and exogenous NO. Finally, taking into account the data available from model bacteria and yeast, a basic draft for the mode of NO action in phytopathogenic microorganisms is proposed. PMID:24822271

  8. The linear chromosome of the plant-pathogenic mycoplasma 'Candidatus Phytoplasma mali'

    Directory of Open Access Journals (Sweden)

    Migdoll Alexander M

    2008-06-01

    Full Text Available Abstract Background Phytoplasmas are insect-transmitted, uncultivable bacterial plant pathogens that cause diseases in hundreds of economically important plants. They represent a monophyletic group within the class Mollicutes (trivial name mycoplasmas and are characterized by a small genome with a low GC content, and the lack of a firm cell wall. All mycoplasmas, including strains of 'Candidatus (Ca. Phytoplasma asteris' and 'Ca. P. australiense', examined so far have circular chromosomes, as is the case for almost all walled bacteria. Results Our work has shown that 'Ca. Phytoplasma mali', the causative agent of apple proliferation disease, has a linear chromosome. Linear chromosomes were also identified in the closely related provisional species 'Ca. P. pyri' and 'Ca. P. prunorum'. The chromosome of 'Ca. P. mali' strain AT is 601,943 bp in size and has a GC content of 21.4%. The chromosome is further characterized by large terminal inverted repeats and covalently closed hairpin ends. Analysis of the protein-coding genes revealed that glycolysis, the major energy-yielding pathway supposed for 'Ca. P. asteris', is incomplete in 'Ca. P. mali'. Due to the apparent lack of other metabolic pathways present in mycoplasmas, it is proposed that maltose and malate are utilized as carbon and energy sources. However, complete ATP-yielding pathways were not identified. 'Ca. P. mali' also differs from 'Ca. P. asteris' by a smaller genome, a lower GC content, a lower number of paralogous genes, fewer insertions of potential mobile DNA elements, and a strongly reduced number of ABC transporters for amino acids. In contrast, 'Ca. P. mali' has an extended set of genes for homologous recombination, excision repair and SOS response than 'Ca. P. asteris'. Conclusion The small linear chromosome with large terminal inverted repeats and covalently closed hairpin ends, the extremely low GC content and the limited metabolic capabilities reflect unique features of 'Ca

  9. Antifungal compounds from turmeric and nutmeg with activity against plant pathogens

    Science.gov (United States)

    The antifungal activity of twenty-two common spices was evaluated against plant pathogens using direct-bioautography coupled Colletotrichum bioassays. Turmeric, nutmeg, ginger, clove, oregano, cinnamon, anise, fennel, basil, black cumin, and black pepper showed antifungal activity against the plant ...

  10. List of new names of plant pathogenic bacteria (2011-2012)

    Science.gov (United States)

    The International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria has responsibility to evaluate the names of newly proposed pathovars for adherence to the International Standards for Naming Pathovars of Phytopathogenic Bacteria. Currently, the Comprehensive List of...

  11. Genetic Diversity of pathogenic and nonpathogenic populations of Phytophthora capsici from pepper plants and soil

    Science.gov (United States)

    Thirty-six Phytophthora capsici strains and one Phytophthora parasitica strain were evaluated for pathogenicity and disease severity on pepper (Capsicum annuum) plants. The strains represent a range of geographic locations and were collected primarily from pepper stems or roots of plants with sympto...

  12. The role of the secondary cell wall in plant resistance to pathogens.

    Science.gov (United States)

    Miedes, Eva; Vanholme, Ruben; Boerjan, Wout; Molina, Antonio

    2014-01-01

    Plant resistance to pathogens relies on a complex network of constitutive and inducible defensive barriers. The plant cell wall is one of the barriers that pathogens need to overcome to successfully colonize plant tissues. The traditional view of the plant cell wall as a passive barrier has evolved to a concept that considers the wall as a dynamic structure that regulates both constitutive and inducible defense mechanisms, and as a source of signaling molecules that trigger immune responses. The secondary cell walls of plants also represent a carbon-neutral feedstock (lignocellulosic biomass) for the production of biofuels and biomaterials. Therefore, engineering plants with improved secondary cell wall characteristics is an interesting strategy to ease the processing of lignocellulosic biomass in the biorefinery. However, modification of the integrity of the cell wall by impairment of proteins required for its biosynthesis or remodeling may impact the plants resistance to pathogens. This review summarizes our understanding of the role of the plant cell wall in pathogen resistance with a focus on the contribution of lignin to this biological process. PMID:25161657

  13. Plant-in-chip: Microfluidic system for studying root growth and pathogenic interactions in Arabidopsis

    Science.gov (United States)

    Parashar, Archana; Pandey, Santosh

    2011-06-01

    We report a microfluidic platform for the hydroponic growth of Arabidopsis plants with high-resolution visualization of root development and root-pathogen interactions. The platform comprises a set of parallel microchannels with individual input/output ports where 1-day old germinated seedlings are initially placed. Under optimum conditions, a root system grows in each microchannel and its images are recorded over a 198-h period. Different concentrations of plant growth media show different root growth characteristics. Later, the developed roots are inoculated with two plant pathogens (nematodes and zoospores) and their physicochemical interactions with the live root systems are observed.

  14. ANTIBACTERIAL ACTIVITY OF THREE MEDICINAL PLANTS OF KUMAUN HIMALAYA AGAINST SOME PATHOGENIC BACTERIA

    Directory of Open Access Journals (Sweden)

    S. C. SATI

    2015-11-01

    Full Text Available The antibacterial property of methanol, ethanol and hexane extracts of Berberis aristata, Chenopodium ambrosioides and Tinospora cordifolia grown in Kumaun Himalayan were investigated against some pathogenic gram positive and gram negative bacterial strains (Bacillus subtilis, Agrobacterium tumefaciens, Escherichia coli, Xanthomonas phaseoli and Erwinia chrysanthemi using disc diffusion method. Methanol extract of B. aristata was found with highest inhibitory activity against E. chrysanthemi (ZOI, 11±0.3mm. Whereas lowest inhibition was recorded in ethanolic extract of B. aristata against E. coli. The hexane extract of B. aristata and methanolic extract of C. ambrosioides were found totally inactive against all the pathogens tested.

  15. Within-host evolution decreases virulence in an opportunistic bacterial pathogen

    OpenAIRE

    Mikonranta, Lauri; Mappes, Johanna; Laakso, Jouni; Ketola, Tarmo

    2015-01-01

    Abstract Background Pathogens evolve in a close antagonistic relationship with their hosts. The conventional theory proposes that evolution of virulence is highly dependent on the efficiency of direct host-to-host transmission. Many opportunistic pathogens, however, are not strictly dependent on the hosts due to their ability to reproduce in the free-living environment. Therefore it is likely that conflicting selection pressures for grow...

  16. A randomized trial of chlorhexidine gluconate on oral bacterial pathogens in mechanically ventilated patients

    OpenAIRE

    Scannapieco, Frank A.; Yu, Jihnhee; Raghavendran, Krishnan; Vacanti, Angela; Owens, Susan I; Wood, Kenneth; Mylotte, Joseph M.

    2009-01-01

    Introduction Dental plaque biofilms are colonized by respiratory pathogens in mechanically-ventilated intensive care unit patients. Thus, improvements in oral hygiene in these patients may prevent ventilator-associated pneumonia. The goal of this study was to determine the minimum frequency (once or twice a day) for 0.12% chlorhexidine gluconate application necessary to reduce oral colonization by pathogens in 175 intubated patients in a trauma intensive care unit. Methods A randomized, doubl...

  17. Bottlenecks in the Transferability of Antibiotic Resistance from Natural Ecosystems to Human Bacterial Pathogens

    OpenAIRE

    Martínez, José L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens through horizontal gene transfer originated in environmental, non-pathogenic bacteria. As a consequence, there is increasing concern on the roles that natural, non-clinical ecosystems, may play in the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance on their expression in a heterologous host is much larger than what is actually found in human...

  18. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    OpenAIRE

    Martinez, Jose L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actu...

  19. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira

    OpenAIRE

    Fouts, Derrick E.; Matthias, Michael A.; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E.; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L.; Haake, David A.; Haft, Daniel H.; Hartskeerl, Rudy; Ko, Albert I.; Levett, Paul N

    2016-01-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field....

  20. Anti-bacterial effects of the essential oil of Teucrium polium L. on human pathogenic bacteria

    OpenAIRE

    Mohammad Mohammad; Hassan Salari; Armita Farahmand

    2013-01-01

    Background: Pathogenic bacteria are important causes of disease in humans and agricultural products contamination. Side effects of chemical preservatives necessitate research on the use of a special blend of natural oils to prevent the growth of bacteria. The aim of this study was elucidating the antibacterial effect of the essential oil of Teucrium polium on human pathogenic bacteria in the Kerman province. Materials and Methods: In order to investigate the chemical composition and antiba...