Taxonomic Study of Bacteria Isolated from Natural Mineral Waters: Proposal of Pseudomonas jessenii sp. nov. and Pseudomonas mandelii sp. nov.

Bacterial growth occurs in noncarbonated natural mineral waters a few days after filling and storage at room temperature, a phenomenon known for more than 40 years. Using the full-cycle rRNA approach, we monitored the development of the planktonic bacterial community in a noncarbonated natural mineral water after bottling. Seven 16S rRNA gene libraries, comprising 108 clones in total, were constructed from water samples taken at various days after bottling and from two different bottle sizes. Sequence analyses identified 11 operational taxonomic units (OTUs), all but one affiliated with the betaproteobacterial order Burkholderiales (6 OTUs) or the class Alphaproteobacteria (4 OTUs). Fluorescence in situ hybridization (FISH) was applied in combination with DAPI (4,6-diamidino-2-phenylindole) staining, viability staining, and microscopic counting to quantitatively monitor changes in bacterial community composition. A growth curve similar to that of a bacterium grown in a batch culture was recorded. In contrast to the current perception that Gammaproteobacteria are the most important bacterial components of natural mineral water in bottles, Betaproteobacteria dominated the growing bacterial community and accounted for 80 to 98% of all bacteria detected by FISH in the late-exponential and stationary-growth phases. Using previously published and newly designed genusspecific probes, members of the betaproteobacterial genera Hydrogenophaga, Aquabacterium, and Polaromonas were found to constitute a significant proportion of the bacterial flora (21 to 86% of all bacteria detected by FISH). For the first time, key genera responsible for bacterial growth in a natural mineral water were identified by applying molecular cultivation-independent techniques.

Section: Discussionmentioning

confidence: 61%

Diversity of Bacteria Growing in Natural Mineral Water after Bottling

Loy

Beisker²,

Meier

2005

“…The strains identified as P. fluorescens biovar I in Table 1 are considered a phenotypic group because their assignation has only been obtained through a conventional limited number of phenotypic characteristics (8). Most of the species and genomospecies in Table 1 have already been described (1,13,16,17,43,47). Three of them, "P. mosselii," "P. palleronii," and "P. salomonii," will soon be published.…”

Section: Methodsmentioning

confidence: 99%

“…Both phenotypic and genomic approaches were essential components of what was to be known as polyphasic taxonomy (46), which allowed the recent description of numerous new species (1,3,6,13,16,17,37,43,47). The present work has focused mainly on fluorescent Pseudomonas strains, including the new species and numerous phenotypic clusters under investigation, and extended to some well-defined nonfluorescent species of the genus, showing that a precise taxonomic allocation which parallels the polyphasic taxonomy data can be simply achieved by siderotyping.…”

mentioning

confidence: 99%

Siderophore Typing, a Powerful Tool for the Identification of Fluorescent and Nonfluorescent Pseudomonads

Meyer

Geoffroy

Baida³

et al. 2002

174

129

A total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through siderotyping, i.e., by the isoelectrophoretic characterization of their main siderophores and pyoverdines and determination of the pyoverdine-mediated iron uptake specificity of the strains. As a general rule, strains within a well-circumscribed taxonomic group, namely the species Pseudomonas brassicacearum, Pseudomonas fuscovaginae, Pseudomonas jessenii, Pseudomonas mandelii, Pseudomonas monteilii, "Pseudomonas mosselii," "Pseudomonas palleronii," Pseudomonas rhodesiae, "Pseudomonas salomonii," Pseudomonas syringae, Pseudomonas thivervalensis, Pseudomonas tolaasii, and Pseudomonas veronii and the genomospecies FP1, FP2, and FP3 produced an identical pyoverdine which, in addition, was characteristic of the group, since it was structurally different from the pyoverdines produced by the other groups. In contrast, 28 strains belonging to the notoriously heterogeneous Pseudomonas fluorescens species were characterized by great heterogeneity at the pyoverdine level. The study of 23 partially characterized phenotypic clusters demonstrated that siderotyping is very useful in suggesting correlations between clusters and welldefined species and in detecting misclassified individual strains, as verified by DNA-DNA hybridization. The usefulness of siderotyping as a determinative tool was extended to the nonfluorescent species Pseudomonas corrugata, Pseudomonas frederiksbergensis, Pseudomonas graminis, and Pseudomonas plecoglossicida, which were seen to have an identical species-specific siderophore system and thus were easily differentiated from one another. Thus, the fast, accurate, and easy-to-perform siderotyping method compares favorably with the usual phenotypic and genomic methods presently necessary for accurate identification of pseudomonads at the species level.

“…A few strains were subjected to further identification (16). One of the IODS (strain MF 381) was determined to be most closely related to Pseudomonas frederiksbergensis (1) (49) and P. frederiksbergensis (99% identity in both cases). There were eight sequences from isolates of Pseudomonas sp.…”

Section: Influence Of Isolation Factors On Dsi (I) Geographic Originmentioning

confidence: 99%

Low-Temperature Isolation of Disease-Suppressive Bacteria and Characterization of a Distinctive Group of Pseudomonads

Johansson

Wright

2003

The influence of environmental factors during isolation on the composition of potential biocontrol isolates is largely unknown. Bacterial isolates that efficiently suppressed wheat seedling blight caused by Fusarium culmorum were found by isolating psychrotrophic, root-associated bacteria and by screening them in a bioassay that mimicked field conditions. The impact of individual isolation factors on the disease-suppressive index (DSI) of almost 600 isolates was analyzed. The bacteria originated from 135 samples from 62 sites in Sweden and Switzerland. The isolation factors that increased the probability of finding isolates with high DSIs were sampling from arable land, Swiss origin of samples, and origination of isolates from plants belonging to the family Brassicaceae. The colony morphology of the isolates was characterized and compared to DSIs, which led to identification of a uniform morphological group containing 57 highly disease-suppressive isolates. Isolates in this group were identified as Pseudomonas sp.; they were fluorescent on King's medium B and had characteristic crystalline structures in their colonies. These isolates were morphologically similar to seven strains that had previously been selected for suppression of barley net blotch caused by Drechslera teres. Members of this morphological group grow at 1.5°C and produce an antifungal polyketide (2,3-deepoxy-2,3-didehydrorhizoxin [DDR]). They have similar two-dimensional polyacrylamide gel electrophoresis protein profiles, phenotypic characteristics, and in vitro inhibition spectra of pathogens. In summary, in this paper we describe some isolation factors that are important for obtaining disease-suppressive bacteria in our system, and we describe a novel group of biocontrol pseudomonads.In biological control, microorganisms isolated from plants and soils are employed to protect crop plants from diseases. In cereals, seed-and soilborne fungal diseases are often suppressed by fluorescent pseudomonads (4,6,16,17,25). These bacteria are well adapted to the rhizosphere environment (for a recent review see reference 29), and they produce several antimicrobial substances that are involved in suppression of plant diseases (7). Many Fusarium species, including Fusarium culmorum, and the related organism Microdochium nivale are well-known and widespread fungal plant pathogens which can cause different diseases at various developmental stages of a crop (36,43). This fact and the risk of triggering increased mycotoxin production by use of fungicides make these fungi difficult to control (30, 36). However, since biological control often operates through several modes of action, it provides new possibilities to address these two issues (15,19,21,25).Screening systems that approximate field conditions are more likely to result in selection of effective biocontrol isolates (12,24,50). In the temperate regions of the world, one critical environmental factor is the low temperature during winter and early spring (12). Hökeberg and et al. (13) developed an isolation...