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Isaac Barash - One of the best experts on this subject based on the ideXlab platform.
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Two Pantoea agglomerans type III effectors can transform nonpathogenic and phytopathogenic bacteria into host-specific gall-forming pathogens.
Molecular plant pathology, 2019Co-Authors: Gal Nissan, Laura Chalupowicz, Shulamit Manulis-sasson, Guido Sessa, Isaac BarashAbstract:Pantoea agglomerans (Pa), a widespread commensal bacterium, has evolved into a host-specific gall-forming pathogen on gypsophila and beet by acquiring a plasmid harbouring a type III secretion system (T3SS) and effectors (T3Es). Pantoea agglomerans pv. gypsophilae (Pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas P. agglomerans pv. betae (Pab) elicits galls on beet and gypsophila. HsvG and HsvB are two paralogous T3Es present in both pathovars and act as host-specific transcription activators on gypsophila and beet, respectively. PthG and PseB are major T3Es that contribute to gall development of Pag and Pab, respectively. To establish the minimal combinations of T3Es that are sufficient to elicit gall symptoms, strains of the nonpathogenic bacteria Pseudomonas fluorescens 55, Pa 3-1, Pa 98 and Escherichia coli, transformed with pHIR11 harbouring a T3SS, and the phytopathogenic bacteria Erwinia amylovora, Dickeya solani and Xanthomonas campestris pv. campestris were transformed with the T3Es hsvG, hsvB, pthG and pseB, either individually or in pairs, and used to infect gypsophila and beet. Strikingly, all the tested nonpathogenic and phytopathogenic bacterial strains harbouring hsvG and pthG incited galls on gypsophila, whereas strains harbouring hsvB and pseB, with the exception of E. coli, incited galls on beet.
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Global regulatory networks control the hrp regulon of the gall-forming bacterium Pantoea agglomerans pv. gypsophilae.
Molecular plant-microbe interactions : MPMI, 2013Co-Authors: Mary Panijel, Shulamit Manulis-sasson, Laura Chalupowicz, Guido Sessa, Isaac BarashAbstract:Gall formation by Pantoea agglomerans pv. gypsophilae is dependent on the hypersensitive response and pathogenicity (hrp) system. Previous studies demonstrated that PagR and PagI, regulators of the quorum-sensing system, induce expression of the hrp regulatory cascade (i.e., hrpXY, hrpS, and hrpL) that activates the HrpL regulon. Here, we isolated the genes of the Gac/Rsm global regulatory pathway (i.e., gacS, gacA, rsmB, and csrD) and of the post-transcriptional regulator rsmA. Our results demonstrate that PagR and PagI also upregulate expression of the Gac/Rsm pathway. PagR acts as a transcriptional activator of each of the hrp regulatory genes and gacA in a N-butanoyl-L-homoserine lactone-dependent manner as shown by gel shift experiments. Mutants of the Gac/Rsm genes or overexpression of rsmA significantly reduced Pantoea agglomerans virulence and colonization of gypsophila. Overexpression of rsmB sRNA abolished gall formation, colonization, and hypersensitive reaction on nonhost plants and prevented transcription of the hrp regulatory cascade, indicating a lack of functional type III secretion system. Expression of rsmB sRNA in the background of the csrD null mutant suggests that CsrD may act as a safeguard for preventing excessive production of rsmB sRNA. Results presented indicate that the hrp regulatory cascade is controlled directly by PagR and indirectly by RsmA, whereas deficiency in RsmA activity is epistatic to PagR induction.
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Recent Evolution of Bacterial Pathogens: The Gall-Forming Pantoea agglomerans Case
Annual review of phytopathology, 2009Co-Authors: Isaac Barash, Shulamit Manulis-sassonAbstract:Pantoea agglomerans, a widespread epiphyte and commensal bacterium, has evolved into an Hrp-dependent and host-specific tumorigenic pathogen by acquiring a plasmid containing a pathogenicity island (PAI). The PAI was evolved on an iteron plasmid of the IncN family, which is distributed among genetically diverse populations of P. agglomerans. The structure of the PAI supports the premise of a recently evolved pathogen. This review offers insight into a unique model for emergence of new bacterial pathogens. It illustrates how horizontal gene transfer was the major driving force in the creation of the PAI, although a pathoadaptive mechanism might also be involved. It describes the crucial function of plant-produced indole-3-acetic acid (IAA) and cytokinines (CK) in gall initiation as opposed to the significant but secondary role of pathogen-secreted phytohormones. It also unveils the role of type III effectors in determination of host specificity and evolution of the pathogen into pathovars. Finally, it desc...
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Virulence mechanisms and host specificity of gall-forming Pantoea agglomerans.
Trends in microbiology, 2007Co-Authors: Isaac Barash, Shulamit Manulis-sassonAbstract:Pantoea agglomerans has been transformed from a commensal bacterium associated with many plants into a host-specific gall-forming pathogen by acquiring a plasmid-borne pathogenicity island. This pathogenicity island harbors the hrp/hrc gene cluster, in addition to genes encoding type III effector proteins, biosynthesis of the phytohormones indole-3-acetic acid and cytokinin, multiple diverse insertion sequences and pseudogenes. This review describes a unique model for understanding the emergence of new pathogens or new pathogenic variants, offering an insight into the function of type III effectors in host specificity and the evolution of a pathogen into pathovars. It also addresses the primary role of type III effectors in gall initiation as compared with a secondary role of phytohormones secreted by the pathogen.
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Pantoea agglomerans pvs. gypsophilae and betae, recently evolved pathogens?
Molecular plant pathology, 2003Co-Authors: Shulamit Manulis, Isaac BarashAbstract:SUMMARY Pantoea agglomerans pvs. gypsophilae and betae Taxonomy: Bacteria; Proteobacteria; gamma subdivision; order Enterobacteriales; family Enterobacteriaceae; species Pantoea agglomerans. Microbiological properties: Gram-negative, non-capsulated, non-spore-forming, predominately motile rode. Disease symptoms: Gall formation at wound sites, mainly in the crown region of the stem. The host range of P. agglomerans pv. gypsophilae is restricted to Gypsophila paniculata, whereas P. agglomerans pv. betae is pathogenic on Beta vulgaris and gypsophila. Disease control: Pathogenic-free transplants and sanitation. No resistant cultivars are available. Major virulence determinants: Pathogenicity plasmid (pPATH), hrp cluster, type III virulence effectors, phytohormones.
Gen-ichiro Soma - One of the best experts on this subject based on the ideXlab platform.
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Characterization of the O-antigen polysaccharide derived from Pantoea agglomerans IG1 lipopolysaccharide
Carbohydrate research, 2017Co-Authors: Masahito Hashimoto, Hiroyuki Inagawa, Rune Satou, Mami Ozono, Gen-ichiro SomaAbstract:A polysaccharide fraction was isolated from the Pantoea agglomerans IG1 lipopolysaccharide (IP-PA1), and its O-antigenic polysaccharide was characterized by chemical analyses and 1D and 2D 1H and 13C NMR spectroscopy. The polysaccharide is composed of linear tetrasaccharide repeating units, consisting of glucose and rhamnose, where 40% of one of the rhamnose residues is substituted with glucose: →2)-α-l-Rhap-(1→6)-α-d-Glcp-(1→2)-[β-d-Glcp-(1→3)]0.4-α-l-Rhap-(1→2)-α-l-Rhap-(1→.
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Genome Sequence of Pantoea agglomerans Strain IG1
Journal of bacteriology, 2012Co-Authors: Tomohiko Matsuzawa, Gen-ichiro Soma, Kazuki Mori, Takeshi Kadowaki, Misato Shimada, Kosuke Tashiro, Satoru Kuhara, Hiroyuki Inagawa, Kaoru TakegawaAbstract:Pantoea agglomerans is a Gram-negative bacterium that grows symbiotically with various plants. Here we report the 4.8-Mb genome sequence of P. agglomerans strain IG1. The lipopolysaccharides derived from P. agglomerans IG1 have been shown to be effective in the prevention of various diseases, such as bacterial or viral infection, lifestyle-related diseases. This genome sequence represents a substantial step toward the elucidation of pathways for production of lipopolysaccharides.
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Development and potential use of a monoclonal antibody to the lipopolysaccharide of Pantoea agglomerans (IP-PA1).
Anticancer research, 2007Co-Authors: Yoshie Taniguchi, Takashi Nishizawa, Hiroyuki Inagawa, Teruko Honda, Noriko Yoshioka, Chie Kohchi, Gen-ichiro SomaAbstract:Background: The lipopolysaccharide of Pantoea agglomerans (IP-PA1) has been shown to be effective and safe in the prevention of various diseases, such as bacterial or viral infection, lifestyle-related diseases, when administered transdermally or orally. To clarify the mechanisms of the preventive or therapeutic effect induced by IP-PA1, we tried to establish a monoclonal antibody to detect IP-PA1. The enzyme-linked immunosorbent assay (ELISA) was used to measure the amount of IP-PA1. Materials and Methods: Antibodies were raised by immunization using heat-killed Pantoea agglomerans and screening was conducted to isolate monoclonal antibodies specific to IP-PA1. Results: Six kinds of IP-PA1 specific monoclonal antibodies with different epitopes were established. An ELISA using the monoclonal antibodies was successfully established which could specifically detect IP-PA1. Conclusion: By use of this ELISA, the staple food content and pharmacodynamic analysis of IP-PA1 could be conveniently estimated.
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Structural characterization of lipid A obtained from Pantoea agglomerans lipopolysaccharide
FEMS microbiology letters, 1997Co-Authors: Daisuke Tsukioka, Takashi Nishizawa, Toshio Miyase, Kazuo Achiwa, Takuya Suda, Gen-ichiro Soma, Den'ichi MizunoAbstract:Lipopolysaccharide isolated from Pantoea agglomerans showed higher priming and triggering activities for macrophages in terms of tumor necrosis factor production than other lipopolysaccharides. To identify the difference in biological activities of lipopolysaccharide of Pantoea agglomerans from other lipopolysaccharides on the basis of structure, we determined the structure of the lipid A part, which is the biological center of lipopolysaccharide, by quantitative analysis, nuclear magnetic resonance spectroscopy and mass spectrometry. Lipopolysaccharide of Pantoea agglomerans is constructed with at least two kinds of lipid A of different levels of acylation. One is of the same type as that of Escherichia coli with hexa-acyl lipid A and the other is the Salmonella minnesota type with hepta-acyl lipid A.
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Antinociceptive effect of lipopolysaccharide from Pantoea agglomerans on streptozotocin-induced diabetic mice.
European journal of pharmacology, 1994Co-Authors: Junzo Kamei, Gen-ichiro Soma, Takafumi Okutomi, Tsutomu Suzuki, Yutaka Kasuya, Yuriko Iwamoto, Miwa Misawa, Hiroshi Nagase, Den'ichi MizunoAbstract:The antinociceptive effect of lipopolysaccharide from Pantoea agglomerans (LPSp) in streptozotocin-induced diabetic mice was examined. Although subcutaneous (s.c.) administration of LPSp produced a dose-dependent inhibition of the tail-flick response in both non-diabetic and diabetic mice, the antinociceptive response was greater in diabetic mice than in non-diabetic mice. The antinociceptive effects of LPSp in both diabetic and non-diabetic mice were significantly antagonized by s.c. administration of naltrindole, a selective δ-opioid receptor antagonist or nor-binaltorphimine, a selective κ-opioid receptor antagonist, but not by β-funaltrexamine, a selective μ-opioid receptor antagonist. These results suggest that LPSp produces a marked antinociceptive effect in diabetic mice through the activation of δ- and κ-opioid receptors.
Russell Steven - One of the best experts on this subject based on the ideXlab platform.
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Effects of Low-Shear Simulated Microgravity on Soil Bacterium Pantoea agglomerans
2019Co-Authors: Russell StevenAbstract:A major stressor in the space environment is microgravity. Microgravity has profound effects on biological processes that are vital to normal functioning. This is most prevalently seen in microorganisms, which have altered growth rates and increased antibiotic susceptibility in microgravity. This is a concern for both astronauts and plants onboard spacecraft. Pantoea agglomerans is a soil bacterium that has been shown to be a plant growth promoter, plant pathogen, and an opportunistic pathogen to immunocompromised patients. Using the ground based microgravity analog, the Rotary Cell Culture System along with the High Aspect-Ratio Vessel, we analyzed the growth and the antibiotic susceptibility of Pantoea agglomerans grown in simulated microgravity. In certain parameters, we discovered an increased growth rate and no change in the antibiotic susceptibility. We found that there were differences in results when certain aspects of the protocol were altered. Further work will need to be conducted to get a better understanding of the changes in the microorganisms exposed to microgravity
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The Effects of Low-Shear Simulated Microgravity on Soil Bacterium Pantoea agglomerans
2019Co-Authors: Russell StevenAbstract:As NASA's effort to establish a permanent residence in space continues, research on the effects of microgravity onbiological microorganisms is vital to protect or promote the health of plants and their astronaut counterparts. The purpose of this study is to determine the effects of microgravity on Pantoea agglomerans (P. agglomerans), using an analog microgravity simulator; the Rotary Cell Culture System (RCCS) developed at Johnson Space Center (JSC) in Houston, TX. P. agglomerans has been shown to be a plant growth promoter (PGPR) in ground based studies, but has also been shown to be a pathogen in both plants and immunocompromised patients. In this study, we will determine changes in the growth rate and antibiotic susceptibility of P. agglomerans when exposed to simulated microgravity
Feng Yong-jun - One of the best experts on this subject based on the ideXlab platform.
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The Effects of Symplasmata Structure of Pantoea agglomerans YS19 on Thallus Resistance against Unfavorable Circumstances
Journal of Microbiology, 2009Co-Authors: Feng Yong-junAbstract:Pantoea agglomerans strain YS19 was a dominant endophyte isolated from rice cv, Yuefu. Symplasmata it formed was a film-like multi-cell aggregate structure; however, its intercellular connection was much tighter than that in biofilms. Study on the contribution of symplasmata structure to P.agglomerans YS19 against unfavorable circumstances is conducive to explain the adaptability of the interaction of endophytes and plants. Symplasmata structure was comparatively studied with separated bacteria on the differences of resistant ability in osmotic shock, heavy metal ions, and arid treatment. The results showed that while facing unfavorable circumstances, thallus that forms symplasmata structure its survival ability apparently strengthen much more than those of separated bacteria.
Shulamit Manulis-sasson - One of the best experts on this subject based on the ideXlab platform.
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Two Pantoea agglomerans type III effectors can transform nonpathogenic and phytopathogenic bacteria into host-specific gall-forming pathogens.
Molecular plant pathology, 2019Co-Authors: Gal Nissan, Laura Chalupowicz, Shulamit Manulis-sasson, Guido Sessa, Isaac BarashAbstract:Pantoea agglomerans (Pa), a widespread commensal bacterium, has evolved into a host-specific gall-forming pathogen on gypsophila and beet by acquiring a plasmid harbouring a type III secretion system (T3SS) and effectors (T3Es). Pantoea agglomerans pv. gypsophilae (Pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas P. agglomerans pv. betae (Pab) elicits galls on beet and gypsophila. HsvG and HsvB are two paralogous T3Es present in both pathovars and act as host-specific transcription activators on gypsophila and beet, respectively. PthG and PseB are major T3Es that contribute to gall development of Pag and Pab, respectively. To establish the minimal combinations of T3Es that are sufficient to elicit gall symptoms, strains of the nonpathogenic bacteria Pseudomonas fluorescens 55, Pa 3-1, Pa 98 and Escherichia coli, transformed with pHIR11 harbouring a T3SS, and the phytopathogenic bacteria Erwinia amylovora, Dickeya solani and Xanthomonas campestris pv. campestris were transformed with the T3Es hsvG, hsvB, pthG and pseB, either individually or in pairs, and used to infect gypsophila and beet. Strikingly, all the tested nonpathogenic and phytopathogenic bacterial strains harbouring hsvG and pthG incited galls on gypsophila, whereas strains harbouring hsvB and pseB, with the exception of E. coli, incited galls on beet.
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Global regulatory networks control the hrp regulon of the gall-forming bacterium Pantoea agglomerans pv. gypsophilae.
Molecular plant-microbe interactions : MPMI, 2013Co-Authors: Mary Panijel, Shulamit Manulis-sasson, Laura Chalupowicz, Guido Sessa, Isaac BarashAbstract:Gall formation by Pantoea agglomerans pv. gypsophilae is dependent on the hypersensitive response and pathogenicity (hrp) system. Previous studies demonstrated that PagR and PagI, regulators of the quorum-sensing system, induce expression of the hrp regulatory cascade (i.e., hrpXY, hrpS, and hrpL) that activates the HrpL regulon. Here, we isolated the genes of the Gac/Rsm global regulatory pathway (i.e., gacS, gacA, rsmB, and csrD) and of the post-transcriptional regulator rsmA. Our results demonstrate that PagR and PagI also upregulate expression of the Gac/Rsm pathway. PagR acts as a transcriptional activator of each of the hrp regulatory genes and gacA in a N-butanoyl-L-homoserine lactone-dependent manner as shown by gel shift experiments. Mutants of the Gac/Rsm genes or overexpression of rsmA significantly reduced Pantoea agglomerans virulence and colonization of gypsophila. Overexpression of rsmB sRNA abolished gall formation, colonization, and hypersensitive reaction on nonhost plants and prevented transcription of the hrp regulatory cascade, indicating a lack of functional type III secretion system. Expression of rsmB sRNA in the background of the csrD null mutant suggests that CsrD may act as a safeguard for preventing excessive production of rsmB sRNA. Results presented indicate that the hrp regulatory cascade is controlled directly by PagR and indirectly by RsmA, whereas deficiency in RsmA activity is epistatic to PagR induction.
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Recent Evolution of Bacterial Pathogens: The Gall-Forming Pantoea agglomerans Case
Annual review of phytopathology, 2009Co-Authors: Isaac Barash, Shulamit Manulis-sassonAbstract:Pantoea agglomerans, a widespread epiphyte and commensal bacterium, has evolved into an Hrp-dependent and host-specific tumorigenic pathogen by acquiring a plasmid containing a pathogenicity island (PAI). The PAI was evolved on an iteron plasmid of the IncN family, which is distributed among genetically diverse populations of P. agglomerans. The structure of the PAI supports the premise of a recently evolved pathogen. This review offers insight into a unique model for emergence of new bacterial pathogens. It illustrates how horizontal gene transfer was the major driving force in the creation of the PAI, although a pathoadaptive mechanism might also be involved. It describes the crucial function of plant-produced indole-3-acetic acid (IAA) and cytokinines (CK) in gall initiation as opposed to the significant but secondary role of pathogen-secreted phytohormones. It also unveils the role of type III effectors in determination of host specificity and evolution of the pathogen into pathovars. Finally, it desc...
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Virulence mechanisms and host specificity of gall-forming Pantoea agglomerans.
Trends in microbiology, 2007Co-Authors: Isaac Barash, Shulamit Manulis-sassonAbstract:Pantoea agglomerans has been transformed from a commensal bacterium associated with many plants into a host-specific gall-forming pathogen by acquiring a plasmid-borne pathogenicity island. This pathogenicity island harbors the hrp/hrc gene cluster, in addition to genes encoding type III effector proteins, biosynthesis of the phytohormones indole-3-acetic acid and cytokinin, multiple diverse insertion sequences and pseudogenes. This review describes a unique model for understanding the emergence of new pathogens or new pathogenic variants, offering an insight into the function of type III effectors in host specificity and the evolution of a pathogen into pathovars. It also addresses the primary role of type III effectors in gall initiation as compared with a secondary role of phytohormones secreted by the pathogen.
