scholarly journals Characterization of a catalase gene from Aeromonas veronii, the digestive-tract symbiont of the medicinal leech

Microbiology ◽  
2007 ◽  
Vol 153 (6) ◽  
pp. 1897-1906 ◽  
Author(s):  
Rita V. M Rio ◽  
Matthias Anderegg ◽  
Joerg Graf
Keyword(s):  
Digestive Tract ◽  
Medicinal Leech ◽  
Catalase Gene ◽  
Aeromonas Veronii

scholarly journals Characterization of the Digestive-Tract Microbiota of Hirudo orientalis, a European Medicinal Leech

2008 ◽  
Vol 74 (19) ◽  
pp. 6151-6154 ◽  
Author(s):  
Alison S. Laufer ◽  
Mark E. Siddall ◽  
Joerg Graf
Keyword(s):  
Digestive Tract ◽  
Bacterial Infections ◽  
Medicinal Leech ◽  
Culture Independent ◽  
Hirudo Verbana ◽  
Culture Dependent

ABSTRACT FDA-approved, postoperative use of leeches can lead to bacterial infections. In this study, we used culture-dependent and culture-independent approaches to characterize the digestive-tract microbiota of Hirudo orientalis. Surprisingly, two Aeromonas species, A. veronii and A. jandaei, were cultured. Uncultured Rikenella-like bacteria were most similar to isolates from Hirudo verbana.

scholarly journals Culture-Independent Characterization of the Digestive-Tract Microbiota of the Medicinal Leech Reveals a Tripartite Symbiosis

2006 ◽  
Vol 72 (7) ◽  
pp. 4775-4781 ◽  
Author(s):  
Paul L. Worthen ◽  
Cindy J. Gode ◽  
Joerg Graf
Keyword(s):  
Bacterial Community ◽  
Digestive Tract ◽  
Medicinal Leech ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
Data Set ◽  
Clone Libraries ◽  
Host Interactions ◽  
Aeromonas Veronii ◽  
Culture Independent

ABSTRACT Culture-based studies of the microbial community within the gut of the medicinal leech have typically been focused on various Aeromonas species, which were believed to be the sole symbiont of the leech digestive tract. In this study, analysis of 16S rRNA gene clone libraries confirmed the presence of Aeromonas veronii and revealed a second symbiont, clone PW3, a novel member of the Rikenellaceae, within the crop, a large compartment where ingested blood is stored prior to digestion. The diversity of the bacterial community in the leech intestinum was determined, and additional symbionts were detected, including members of the α-, γ-, and δ-Proteobacteria, Fusobacteria, Firmicutes, and Bacteroidetes. The relative abundances of the clones suggested that A. veronii and the novel clone, PW3, also dominate the intestinum community, while other clones, representing transient organisms, were typically present in low numbers. The identities of these transients varied greatly between individual leeches. Neither time after feeding nor feeding on defibrinated blood caused a change in identity of the dominant members of the microbial communities. Terminal restriction fragment length polymorphism analysis was used to verify that the results from the clone libraries were representative of a larger data set. The presence of a two-member bacterial community in the crop provides a unique opportunity to investigate both symbiont-symbiont and symbiont-host interactions in a natural model of digestive-tract associations.

scholarly journals Spatial and Temporal Population Dynamics of a Naturally Occurring Two-Species Microbial Community inside the Digestive Tract of the Medicinal Leech

2007 ◽  
Vol 73 (6) ◽  
pp. 1984-1991 ◽  
Author(s):  
Yoshitomo Kikuchi ◽  
Joerg Graf
Keyword(s):  
Population Dynamics ◽  
Digestive Tract ◽  
Bacterial Species ◽  
Single Species ◽  
Medicinal Leech ◽  
Aeromonas Veronii ◽  
Lectin Staining ◽  
Naturally Occurring ◽  
Hirudo Verbana

ABSTRACT The medicinal leech, Hirudo verbana, is one of the simplest naturally occurring models for digestive-tract symbioses, where only two bacterial species, Aeromonas veronii bv. sobria (γ-Proteobacteria) and a Rikenella-like bacterium (Bacteroidetes), colonize the crop, the largest compartment of the leech digestive tract. In this study, we investigated spatial and temporal changes of the localization and microcolony structure of the native symbionts in the crop, after ingestion of a sterile blood meal, by fluorescence in situ hybridization. The population dynamics differed between the two symbiotic bacteria. A. veronii was detected mainly as individual cells inside the intraluminal fluid (ILF) during 14 days after feeding (daf) unless it was found in association with Rikenella microcolonies. The Rikenella-like bacteria were observed not only inside the ILF but also in association with the luminal surface of the crop epithelium. The sizes of Rikenella microcolonies changed dynamically through the 14-day period. From 3 daf onward, mixed microcolonies containing both species were frequently observed, with cells of both species tightly associating with each other. The sizes of the mixed microcolonies were consistently larger than the size of either single-species microcolony, suggesting a synergistic interaction of the symbionts. Lectin staining with succinylated wheat germ agglutinin revealed that the planktonic microcolonies present in the ILF were embedded in a polysaccharide matrix containing N-acetylglucosamine. The simplicity, symbiont-symbiont interaction, and mixed microcolonies of this naturally occurring, digestive-tract symbiosis lay the foundation for understanding the more complex communities residing in most animals.

scholarly journals Ingested Blood Contributes to the Specificity of the Symbiosis of Aeromonas veronii Biovar Sobria andHirudo medicinalis, the Medicinal Leech

2000 ◽  
Vol 66 (11) ◽  
pp. 4735-4741 ◽  
Author(s):  
Stefan Indergand ◽  
Joerg Graf
Keyword(s):  
Digestive Tract ◽  
Membrane Attack Complex ◽  
Antimicrobial Properties ◽  
Medical Application ◽  
Medicinal Leech ◽  
Symbiotic Interaction ◽  
E Coli ◽  
Aeromonas Veronii ◽  
The Complement System

ABSTRACT Hirudo medicinalis, the medicinal leech, usually carries in its digestive tract a pure culture of Aeromonas veronii bv. sobria. Such specificity is unusual for digestive tracts that are normally colonized by a complex microbial consortium. Important questions for the symbiotic interaction and for the medical application after microvascular surgery are whether other bacteria can proliferate or at least persist in the digestive tract of H. medicinalis and what factors contribute to the reported specificity. Using a colonization assay, we were able to compare experimentally the ability of clinical isolates and of a symbiotic strain to colonize H. medicinalis. The symbiotic A. veronii bv. sobria strain proliferated well and persisted for at least 7 days inside the digestive tract. In contrast, the proliferation of Pseudomonas aeruginosa and Staphylococcus aureus was inhibited inside the animal compared to growth in the in vitro control, indicating that the ingested blood was modified within the digestive tract. However, both strains were able to persist in the digestive tract for at least 7 days. For an Escherichia coli strain, the viable counts decreased approximately 1,000-fold within 42 h. The decrease of viable E. coli could be prevented by interfering with the activation of the membrane-attack complex of the complement system that is present in blood. This suggests that the membrane-attack complex remained active insideH. medicinalis and prevented the proliferation of sensitive bacteria. Thus, antimicrobial properties of the ingested vertebrate blood contribute to the specificity of the A. veronii-H. medicinalis symbiosis, in addition to modifications of the blood inside the digestive tract of H. medicinalis.

scholarly journals Draft Genome Sequence of Aeromonas veronii Hm21, a Symbiotic Isolate from the Medicinal Leech Digestive Tract

2013 ◽  
Vol 1 (5) ◽  
Author(s):  
L. Bomar ◽  
W. Z. Stephens ◽  
M. C. Nelson ◽  
K. Velle ◽  
K. Guillemin ◽  
...  
Keyword(s):  
Digestive Tract ◽  
Genome Sequence ◽  
Draft Genome ◽  
Medicinal Leech ◽  
Draft Genome Sequence ◽  
Aeromonas Veronii

scholarly journals Complement Resistance Is Essential for Colonization of the Digestive Tract of Hirudo medicinalis by Aeromonas Strains

2003 ◽  
Vol 69 (7) ◽  
pp. 4268-4271 ◽  
Author(s):  
Thomas R. Braschler ◽  
Susana Merino ◽  
Juan M. Tomás ◽  
Joerg Graf
Keyword(s):  
Digestive Tract ◽  
Complement System ◽  
Medicinal Leech ◽  
Hirudo Medicinalis ◽  
Aeromonas Veronii ◽  
Complement Resistance

ABSTRACT From the crop of the medicinal leech, Hirudo medicinalis, only Aeromonas veronii bv. sobria can be cultured consistently. Serum-sensitive A. veronii mutants were unable to colonize H. medicinalis, indicating the importance of the mammalian complement system for this unusual simplicity. Complementation of one selected mutant restored its ability to colonize. Serum-sensitive mutants are the first mutant class with a colonization defect for this symbiosis.

scholarly journals Symbiosis of Aeromonas veronii Biovar sobria and Hirudo medicinalis, the Medicinal Leech: a Novel Model for Digestive Tract Associations

1999 ◽  
Vol 67 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Joerg Graf
Keyword(s):  
Digestive Tract ◽  
Bacterial Species ◽  
Bacterial Flora ◽  
Variable Region ◽  
Medicinal Leech ◽  
Hirudo Medicinalis ◽  
Bacterial Growth Rate ◽  
Culturable Bacterium ◽  
Aeromonas Veronii

ABSTRACT Hirudo medicinalis, the medicinal leech, is applied postoperatively in modern medicine. Infections by Aeromonasoccur in up to 20% of patients unless a preemptive antibiotic treatment is administered. The associated infections demonstrate the need for a better understanding of the digestive tract flora ofH. medicinalis. Early studies reported the presence of a single bacterial species in the digestive tract and suggested that these bacteria were endosymbionts contributing to the digestion of blood. In this study, we cultivated bacteria from the digestive tract and characterized them biochemically. The biochemical test results identified the isolates as Aeromonas veronii biovar sobria. This species identification was supported by sequence comparison of a variable region of the genes coding for 16S rRNA. In a colonization assay, a rifampin-resistant derivative of a symbiotic isolate was fed in a blood meal to H. medicinalis. The strain colonized the digestive tract rapidly and reached a concentration similar to that of the native bacterial flora. For the first 12 h, the in vivo doubling time was 1.2 h at 23°C. After 12 h, at a density of 5 × 107 CFU/ml, the increase in viable counts ceased, suggesting a dramatic reduction in the bacterial growth rate. Two human fecal isolates, identified as Aeromonas hydrophila and A. veronii biovar sobria, were also able to colonize the digestive tract. These data demonstrate that the main culturable bacterium in the crop of H. medicinalis isA. veronii biovar sobria and that the medicinal leech can be used as a model for digestive tract association ofAeromonas species.

scholarly journals Identification of Aeromonas veronii Genes Required for Colonization of the Medicinal Leech, Hirudo verbana

2007 ◽  
Vol 189 (19) ◽  
pp. 6763-6772 ◽  
Author(s):  
Adam C. Silver ◽  
Natasha M. Rabinowitz ◽  
Stefan Küffer ◽  
Joerg Graf
Keyword(s):  
Digestive Tract ◽  
Pathogenic Bacteria ◽  
Antimicrobial Property ◽  
Sodium Dodecyl ◽  
Medicinal Leech ◽  
Wild Type ◽  
Aeromonas Veronii ◽  
Hirudo Verbana

ABSTRACT Most digestive tracts contain a complex consortium of beneficial microorganisms, making it challenging to tease apart the molecular interactions between symbiont and host. The digestive tract of Hirudo verbana, the medicinal leech, is an ideal model system because it harbors a simple microbial community in the crop, comprising the genetically amenable Aeromonas veronii and a Rikenella-like bacterium. Signature-tagged mutagenesis (STM) was used to identify genes required for digestive tract colonization. Of 3,850 transposon (Tn) mutants screened, 46 were identified as colonization mutants. Previously we determined that the complement system of the ingested blood remained active inside the crop and prevented serum-sensitive mutants from colonizing. The identification of 26 serum-sensitive mutants indicated a successful screen. The remaining 20 serum-resistant mutants are described in this study and revealed new insights into symbiont-host interactions. An in vivo competition assay compared the colonization levels of the mutants to that of a wild-type competitor. Attenuated colonization mutants were grouped into five classes: surface modification, regulatory, nutritional, host interaction, and unknown function. One STM mutant, JG736, with a Tn insertion in lpp, encoding Braun's lipoprotein, was characterized in detail. This mutant had a >25,000-fold colonization defect relative to colonization by the wild-type strain at 72 h and, in vitro, an increased sensitivity to sodium dodecyl sulfate, suggesting the presence of an additional antimicrobial property in the crop. The classes of genes identified in this study are consistent with findings from previous STM studies involving pathogenic bacteria, suggesting parallel molecular requirements for beneficial and pathogenic host colonization.

scholarly journals Structural Studies of the Lipopolysaccharide of Aeromonas veronii bv. sobria Strain K133 which Represents New Provisional Serogroup PGO1 Prevailing among Mesophilic Aeromonads on Polish Fish Farms

2021 ◽  
Vol 22 (8) ◽  
pp. 4272
Author(s):  
Katarzyna Dworaczek ◽  
Maria Kurzylewska ◽  
Magdalena Laban ◽  
Dominika Drzewiecka ◽  
Agnieszka Pękala-Safińska ◽  
...  
Keyword(s):  
Epidemiological Data ◽  
13C Nmr Spectroscopy ◽  
Freshwater Species ◽  
Fish Farms ◽  
1H And 13C Nmr ◽  
Aeromonas Veronii ◽  
Specific Polysaccharide ◽  
O Antigens ◽  
Unique Composition

In the present work, we performed immunochemical studies of LPS, especially the O-specific polysaccharide (O-PS) of Aeromonas veronii bv. sobria strain K133, which was isolated from the kidney of carp (Cyprinus carpio L.) during an outbreak of motile aeromonad infection/motile aeromonad septicemia (MAI/MAS) on a Polish fish farm. The structural characterization of the O-PS, which was obtained by mild acid degradation of the LPS, was performed with chemical methods, MALDI-TOF mass spectrometry, and 1H and 13C NMR spectroscopy. It was revealed that the O-PS has a unique composition of a linear tetrasaccharide repeating unit and contains a rarely occurring sugar 2,4-diamino-2,4,6-trideoxy-D-glucose (bacillosamine), which may determine the specificity of the serogroup. Western blotting and ELISA confirmed that A. veronii bv. sobria strain K133 belongs to the new serogroup PGO1, which is one of the most commonly represented immunotypes among carp and trout isolates of Aeromonas sp. in Polish aquacultures. Considering the increase in the MAI/MAS incidences and their impact on freshwater species, also with economic importance, and in the absence of an effective immunoprophylaxis, studies of the Aeromonas O-antigens are relevant in the light of epidemiological data and monitoring emergent pathogens representing unknown antigenic variants and serotypes.

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