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Int J Syst Evol Microbiol 53 (2003), 695-704; DOI  10.1099/ijs.0.02346-0
© 2003 International Union of Microbiological Societies

Phylogenetic relationships between Bacillus species and related genera inferred from comparison of 3' end 16S rDNA and 5' end 16S–23S ITS nucleotide sequences

Dong Xu and Jean-Charles Côté

Agriculture and Agri-Food Canada, Research Centre, 430 Gouin Blvd, St-Jean-sur-Richelieu, Quebec, Canada J3B 3E6

Correspondence
Jean-Charles Côté
cotejc{at}agr.gc.ca


    ABSTRACT
 TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
The nucleotide sequences of the 3' end of the 16S rDNA and the 16S–23S internal transcribed spacer (ITS) of 40 Bacillaceae species were determined. These included 21 Bacillus, 9 Paenibacillus, 6 Brevibacillus, 2 Geobacillus, 1 Marinibacillus and 1 Virgibacillus species. Comparative sequence analysis of a 220 bp region covering a highly conserved 150 bp sequence located at the 3' end of the 16S rRNA coding region and a conserved 70 bp sequence located at the 5' end of the 16S–23S ITS of the 40 species and six sequences available in GenBank were used to infer the phylogenetic relationships between all 46 taxa. When a maximal distance (Dmax, where D refers to the number of nucleotide substitutions per site) of 0·31 was introduced as a threshold to determine groupings, 10 phylogenetically distinct clusters were revealed. Twenty-six Bacillus species were separated in seven groups (I, II, III, IV, V, VI and X), but Bacillus circulans remained ungrouped. All six Brevibacillus species under study were in Group VII. The nine Paenibacillus species fell into two distinct groups (VIII and IX). Species with Dmax values within 0·05 were considered to be very closely related. These were Bacillus psychrophilus and Bacillus psychrosaccharolyticus in Group II; ‘Bacillus maroccanus’ and Bacillus simplex in Group II; Bacillus amyloliquefaciens, Bacillus atrophaeus, Bacillus mojavensis and Bacillus subtilis in Group VI; Bacillus fusiformis and Bacillus sphaericus in Group VI; Brevibacillus brevis and Brevibacillus formosus in Group VII; Paenibacillus gordonae and Paenibacillus validus in Group VIII; and Bacillus anthracis, Bacillus cereus, Bacillus mycoides and Bacillus thuringiensis in Group X. The phylogenetic classification presented here is, in general, in agreement with current classifications based on phenotypic and molecular data. Our findings suggest, however, that in some cases, further divisions or, conversely, further groupings might be warranted. Should current classifications be re-examined in the light of our results, Dmax values of 0·31 and 0·05, as exemplified here, may prove useful threshold values for the grouping of Bacillaceae into taxa akin to genera and species, respectively. These Dmax thresholds may also reveal, in a different way, bacterial species for which further characterization might be warranted for proper classification and/or reassignment.


Abbreviations: Dmax, maximal distance, where distance D refers to the number of nucleotide substitutions per site; ITS, internal transcribed spacer

Published online ahead of print on 19 September 2002 as DOI 10.1099/ijs.0.02346-0.

The GenBank accession numbers for the 16S rDNA and 16S–23S ITS of different strains of Bacillus and related genera used in this work are AF478062AF478111.


    INTRODUCTION
 TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
As of 1986 (Claus & Berkeley, 1986Go), the genus Bacillus has encompassed a variety of phenotypically heterogeneous species exhibiting a wide range of nutritional requirements, physiological and metabolic diversity and DNA base composition. Numerical classification based on a series of phenetic characters has been used for the classification of 368 Bacillus strains into 79 clusters (Priest et al., 1988Go). At about the same time, rRNA sequences were being established as a most useful molecular chronometer to infer phylogenetic relationships because they are present in all organisms and changes in the nucleotide sequences were deemed to occur in a clocklike manner (Woese, 1987Go). Soon, several Bacillus species were reclassified based on 16S rDNA sequence alignment. Rössler et al. (1991)Go grouped nine Bacillus species into four clusters. Ash et al. (1991)Go separated 51 Bacillus species into five phylogenetically distinct clusters. Further characterizations at the genotypic and phenotypic levels of selected Bacillus species have led to the creation of several new genera: Amphibacillus (Niimura et al., 1990Go), Alicyclobacillus (Wisotzkey et al., 1992Go), Paenibacillus (Ash et al., 1993Go), Aneurinibacillus and Brevibacillus (Shida et al., 1996aGo), Virgibacillus (Heyndrickx et al., 1998Go), Gracilibacillus and Salibacillus (Wainø et al., 1999Go), Filobacillus (Schlesner et al., 2001Go), Geobacillus (Nazina et al., 2001Go), Ureibacillus (Fortina et al., 2001Go), and Jeotgalibacillus and Marinibacillus (Yoon et al., 2001Go). Recently, partial 16S rDNA sequence (Goto et al., 2000Go) and rRNA gene restriction patterns (Joung & Côté, 2002Go) have been used for the rapid identification or classification of Bacillus species and related genera, respectively.

The 16S–23S internal transcribed spacer (ITS) region has been widely studied for the presence of functional motifs (Berg et al., 1989Go; Nodwell & Greenblatt, 1993Go; Pfeiffer & Hartmann, 1997Go), specific processing sites (Apirion & Miczak, 1993Go) and secondary structures (Nour, 1998Go; Liiv et al., 1998Go). Because the 16S–23S ITS region is hypervariable, as opposed to the more conserved 16S rRNA coding region, it has also been used in the study of prokaryotic diversity at the species and subspecies levels (Gürtler & Stanisich, 1996Go; García-Martínez et al., 1999Go). The ITS-PCR fingerprints have been used to reveal length polymorphisms between Bacillus species (Daffonchio et al., 1998aGo) and at the intra-specific level (Daffonchio et al., 1998bGo). Part of the ITS has been amplified by PCR and used as a probe for the detection, identification and phylotyping of Bacillus species (de Silva et al., 1998Go).

The current classification of species within the genus Bacillus and correlated genera is well established and is based on a combination of numerous experimental approaches. In the present study, we aimed to determine whether or not a combination of part of the 16S rRNA conserved sequence with part of the 16S–23S ITS hypervariable sequence could be informative enough to be used as a simple, useful marker for the classification of Bacillus species and related genera. A nucleotide sequence containing the last 150 bp located at the 3' end of the 16S rRNA coding region and the first 70 bp located at the 5' end of the 16S–23S ITS was used to infer the phylogenetic relationships between 46 Bacillaceae species and eight more distant bacterial species. The robustness of this classification will be assessed by comparison with the current Bacillaceae classifications.


    METHODS
 TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
Bacterial strains and culture conditions.
All the Bacillaceae species used in this study were obtained from the American Type Culture Collection (ATCC) (Table 1Go). They were grown following ATCC guidelines (Pienta et al., 1996Go).


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Table 1. Bacillaceae species used in this study, and GenBank accession numbers for 16S rDNA and 16S–23S ITS sequences

 
Escherichia coli strain TOP10 (Invitrogen) was used for cloning PCR fragments. Strain TOP10 was cultured on LB agar plates to select transformants or in LB broth, with shaking at 180–200 r.p.m. at 37 °C, overnight. When necessary, kanamycin was added to the medium at a final concentration of 50 µg ml-1.

DNA extraction.
For the total DNA isolation, bacterial cells were washed with TESS buffer [10 mM Tris/HCl, 1 mM Na2EDTA, 0·1 M NaCl and 0·1 % Sarkosyl (N-lauroylsarcosine)] and resuspended in TE buffer (10 mM Tris/HCl, 1 mM Na2EDTA). Cells were lysed with 50 mg lysozyme ml-1 and 0·1 % SDS. The subsequent phenol/chloroform extractions and ethanol precipitation were carried out as described by Sambrook et al. (1989)Go.

Recombinant plasmid from E. coli strain TOP10 was isolated using the alkaline-lysis method (Stephen et al., 1990Go) with some modifications. Sodium acetate (pH 5·2) was used to replace potassium acetate for renaturing DNA. After removing cell debris and chromosomal DNA by centrifugation, an equal volume of 7·5 M ammonium sulfate was added to precipitate RNA. The RNA was removed by centrifugation at 13 000 r.p.m. for 20 min. Plasmid DNA was precipitated with 2 vols ethanol, and the pellet was air-dried and resuspended in sterile water.

Amplification of the 3' end 16S rDNA and the 16S–23S ITS region.
The 3' end of 16S rDNA, the 16S–23S ITS region and the 5' end of 23S rDNA was amplified with a pair of primers: L516SF (5'-TCGCTAGTAATCGCGGATCAGC-3') and L523SR (5'-GCATATCGGTGTTAGTCCCGTCC-3'). Amplification was performed in a Thermal Cycler 9600 (Perkin Elmer) in a total volume of 50 µl containing about 50 ng DNA, 0·25 µM each primer, 200 µM dNTP, 1·5 mM MgCl2 and 1·25 U Taq DNA polymerase (Qiagen). PCR was performed under the following conditions: 45 s at 95 °C and then 30 cycles of 15 s at 94 °C, 30 s at 53 °C and 90 s at 72 °C. Amplification products were visualized on agarose gels.

Cloning and sequencing methods.
The amplified DNAs were cloned into a pCRII-TOPO cloning vector using the TOPO TA cloning kit (Invitrogen), following the manufacturer's instructions. Transformants were selected on LB agar plates containing kanamycin (50 µg ml-1), X-Gal (40 µg ml-1) and IPTG (0·5 mM). A single clone was selected for each Bacillaceae species. The recombinant plasmids were isolated using the alkaline-lysis method, digested with EcoRI and visualized on agarose gels to confirm the presence of an inserted fragment.

The dideoxynucleotide chain-termination method (Sanger et al., 1977Go), using the near-infrared fluorescence automated DNA sequencer (LI-COR model 4200), was used to sequence the DNA fragments.

Sequence analysis.
The 3' end of the 16S rDNA and the 16S–23S ITS of the 40 Bacillaceae species sequenced in this study, as well as six other Bacillus sequences (Table 1Go), and eight other sequences from more distant species available in the GenBank database (Clostridium perfringens, AB045290; Sarcina ventriculi, AF110272; Lactobacillus pantheris, AF413523; Desulfotomaculum kuznetsovii, AY036903; Thermoactinomyces vulgaris, AF138739; Streptococcus gallolyticus, AF323911; Deinococcus radiodurans, NC_001263; Salmonella enterica’, NC_003198), were used for comparison. The sequences were aligned using the CLUSTAL W program (Thompson et al., 1994Go) and the most parsimonious phylogenetic trees were constructed using the DNAPARS program of the PHYLIP package, version 3.6a2 (Felsenstein, 1989Go, 2001Go). The order of the input sequences was randomized by DNAPARS. Stability of the groupings was estimated by bootstrap analysis on 100 trees using SEQBOOT in the same package. Trees were visualized using TREEVIEW software, version 1.6.1 (Page, 1996Go).


    RESULTS AND DISCUSSION
 TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
Two primers, one located about 200 nt upstream from the 3' end of the 16S rRNA gene, the other about 80 nt downstream from the 5' end of the 23S rRNA gene, were used to amplify the last 200 bp of the 16S rRNA gene and the entire 16S–23S ITS region from 40 Bacillaceae species. These included 21 Bacillus, 9 Paenibacillus, 6 Brevibacillus, 2 Geobacillus, 1 Virgibacillus and 1 Marinibacillus species. The amplified fragments varied in length from 450 to 850 bp. They were cloned and their nucleotide sequences determined. The homologous DNA sequences from six more Bacillus species, Bacillus anthracis, Bacillus cereus, Bacillus mycoides, Bacillus halodurans, Bacillus subtilis and Bacillus thuringiensis, available in GenBank, were added (Table 1Go). A multiple alignment of the nucleotide sequences from these 46 Bacillaceae species was performed.

Conservation of the 3' end 16S rRNA coding region
Comparative analysis of the 3' end 16S rRNA coding region reveals that at least the last 157 bp share extensive nucleotide identities with all 46 Bacillaceae species (alignment available as supplementary data in IJSEM Online at http://ijs.sgmjournals.org). This sequence encompasses the 16S rRNA gene highly conserved regions 2, 3 and 4 (Lane et al., 1985Go; Weisburg et al., 1991Go; Gürtler & Stanisich, 1996Go) located at nucleotide positions -157 to -140, -52 to -38, and -20 to -4, respectively. Region 2 is believed to be the most highly conserved sequence in eubacteria, archaea and eukaryotes (Lane et al., 1985Go). Regions 3 and 4 are present in many eubacteria (Weisberg et al., 1991Go). Region 2 was identical for all 46 Bacillaceae species analysed, except for Bacillus anthracis for which the corresponding sequence was not available in full. Only Bacillus cereus showed a nucleotide substitution in region 3, at position -38, where deoxyadenosine is replaced by deoxyguanosine. All six Brevibacillus species, Brevibacillus agri, Brevibacillus borstelensis, Brevibacillus brevis, Brevibacillus choshinensis, Brevibacillus formosus and Brevibacillus parabrevis shared the same nucleotide substitution: C to A in region 4, at nucleotide position -18.

The alignment of the 157 bp sequences of the 3' end 16S rDNA of the 46 Bacillaceae species (Table 1Go) and species of five more Gram-positive genera, Clostridium perfringens, Sarcina ventriculi, Lactobacillus pantheris, Desulfotomaculum kuznetsovii and Thermoactinomyces vulgaris, two Gram-positive cocci, Streptococcus gallolyticus and Deinococcus radiodurans, and a Gram-negative, ‘Salmonella enterica’, was used to construct a phylogenetic tree (Fig. 1Go). All 46 Bacillaceae species listed in Table 1Go are present in the main Group A. Lactobacillus pantheris, Sarcina ventriculi and Clostridium perfringens formed the small Group B, whereas Deinococcus radiodurans, ‘Salmonella enterica’, Desulfotomaculum kuznetsovii, Thermoactinomyces vulgaris and Streptococcus gallolyticus remained ungrouped. Within Group A, both Geobacillus species, all nine Paenibacillus species and all six Brevibacillus species can each be traced to respective common nodes, exclusive of other genera. Some closely related species, such as Bacillus atrophaeus and Bacillus mojavensis; Bacillus lentus and Bacillus insolitus; Geobacillus kaustophilus and Geobacillus stearothermophilus; Bacillus halodurans and Bacillus anthracis; Bacillus psychrophilus and Bacillus psychrosaccharolyticus; Brevibacillus borstelensis, Brevibacillus brevis and Brevibacillus formosus; Brevibacillus parabrevis and Brevibacillus agri; Paenibacillus gordonae and Paenibacillus validus; and Paenibacillus alvei, Paenibacillus macerans and Paenibacillus larvae, could not be distinguished from each other. Clearly, the 157 bp sequence at the 3' end 16S rDNA was sufficient to distinguish the bacterial genera under study, separate genera closely related to Bacillus (Group A) from other more distant genera and cluster species within genera for Geobacillus, Paenibacillus and Brevibacillus. It could not, however, distinguish closely related species.



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Fig. 1. Phylogenetic relationships of 46 Bacillus, Brevibacillus, Paenibacillus, Virgibacillus species, and 8 distant species inferred from the alignment of the 157 bp 3' end 16S rRNA coding region. Bootstrap values (expressed as percentages of 100 replications) are shown at branch points; values greater than 50 % were considered significant. The bar represents the unit length of the number of nucleotide substitutions per site. Abbreviations: B., Bacillus; Br., Brevibacillus; G., Geobacillus; M., Marinibacillus; P., Paenibacillus; V., Virgibacillus.

 
Conserved region of 16S–23S ITS between alleles
A total of three, two, three, three and four PCR fragments from different alleles of the 16S–23S ITS regions were cloned from Bacillus amyloliquefaciens, Brevibacillus borstelensis, Bacillus fusiformis, Bacillus licheniformis and Bacillus lentus, respectively (Fig. 2Go). The lengths of each 16S–23S ITS copy were 172, 230 and 348 bp for Bacillus amyloliquefaciens; 232, 303 and 344 bp for Bacillus fusiformis; 168, 172 and 334 bp for Bacillus licheniformis; and 222, 273, 304 and 432 bp for Bacillus lentus. Two incomplete copies of 567 and 629 bp were obtained for Brevibacillus borstelensis. In each species, only the longest 16S–23S ITS copies carried two tRNA genes: tRNAile and tRNAala, except Brevibacillus borstelensis for which both ITS copies (ITS 1 and ITS 2, Fig. 2cGo) harboured the two tRNA genes.



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Fig. 2. Schematic representation of allelic 16S–23S rDNA ITS in (a) Bacillus subtilis, (b) Bacillus amyloliquefaciens, (c) Brevibacillus borstelensis, (d) Bacillus fusiformis, (e) Bacillus licheniformis and (f) Bacillus lentus. The open boxes represent regions of homologous nucleotide sequences between corresponding ITSs, within the same bacteria. Boxes with left and right diagonal lines represent tRNAile and tRNAala, respectively. The solid lines represent sequences lacking conservation between allelic ITSs. The dotted lines in (c) refer to incomplete ITS sequences. The blank spaces between boxes and/or lines represent deletions. A scale in base pairs is placed under the ITS alleles of each species.

 
The nucleotide sequences of the 16S–23S ITS alleles were aligned for each species, respectively. The results of the alignments revealed how the homology was distributed within the 16S–23S ITS. It is interesting to note that the 5' end 16S–23S ITS is conserved between alleles of the same strain. This holds true for the five species tested. It also proved true for the 10 16S–23S ITS allelic sequences of Bacillus subtilis (Fig. 2aGo) available from GenBank and the seven allelic sequences in Bacillus halodurans (data not shown). The conserved 5' end 16S–23S ITS was at least 70 bp long in each bacterial strain studied. For Brevibacillus borstelensis this conserved region between both alleles was nearly 400 bp long (Fig. 2cGo).

In most cases, the central part of the 16S–23S ITS studied was less conserved. Deletions most often occurred in the region harbouring the tRNAile and tRNAala genes. Both tRNA genes were either coexistent or absent on the same allele. In no case was only either of the tRNA genes present. Whether or not the deletion of both tRNA genes on some alleles might be a consequence of gene regulation is debatable.

For some species, like Bacillus subtilis and Bacillus amyloliquefaciens, the 3' end of the 16S–23S ITS region was also highly conserved between alleles. For the other species under study, this region was either less conserved or the conserved region was short.

To determine whether or not the conservation of the first 70 bp of the 5' end of 16S–23S ITS allelic sequences within strains could be extended to other bacteria, copies of the 16S–23S ITS allelic sequences of seven Gram-positive bacteria available from GenBank were compared (alignment data not shown). These included Streptococcus pyogenes MGAS8232 (GenBank NC_003485), Streptococcus pyogenes M1 GAS (NC_002737), Streptococcus pneumoniae (NC_003098), Staphylococcus aureus (NC_003923), Listeria monocytogenes (NC_003210), Clostridium acetobutylicum (NC_003030) and Clostridium perfringens (NC_003366). They contained 6, 6, 4, 5, 6, 11 and 10 16S–23S ITS allelic sequences, respectively. The nucleotide sequence alignment of the 16S–23S ITS alleles showed that the first 70 bp were highly conserved between alleles of the same strain. They were also highly conserved between alleles of strains belonging to the same species, as exemplified by Streptococcus pyogenes MGAS8232 and Streptococcus pyogenes M1 GAS. The first 70 bp were not, however, conserved between alleles of different species of the same genus as exemplified by Streptococcus pyogenes and Streptococcus pneumoniae and by Clostridium acetobutylicum and Clostridium perfringens. This is in agreement with our results on selected species of Bacillus and related genera.

Bourque et al. (1995)Go have amplified, cloned and sequenced a single copy of the 16S–23S ITS of seven different Bacillus thuringiensis varieties and 18 Bacillus thuringiensis var. kurstaki strains. The length of the 16S–23S ITS for each Bacillus thuringiensis strain was around 144 bp and its nucleotide sequence was highly conserved throughout the strains. This suggests that the entire 16S–23S ITS region is conserved among alleles of any given Bacillus thuringiensis strains and between Bacillus thuringiensis varieties. Our results indicate that the 16S–23S ITS is not always conserved, even between allelic sequences within a bacterial strain, but the first 70 nt at the 5' end of 16S–23S ITS are conserved between alleles within strains and within species.

Although the sequences of the first 70 nt at the 5' 16S–23S ITS are conserved between the rrn alleles within a strain or within a species, the nucleotide identities between different species were quite variable (alignment data not shown). In some cases, no meaningful similarities in the 5' 16S–23S ITS region were observed between species of the same genus. The 5' end of the 16S–23S ITS nucleotide sequence could be species-specific and might provide a rapid, easy and useful marker for species discrimination and identification.

Phylogenetic analysis
The two highly conserved sequences identified above, the last 150 bp located at the 3' 16S rDNA and the first 70 bp located at the 5' 16S–23S ITS, were combined into a 220 bp sequence. A most parsimonious phylogenetic tree was constructed with the DNAPARS program of the PHYLIP package using the alignment of the 220 bp sequences of the 40 Bacillaceae species sequenced in this study and those of six Bacillus species available in GenBank (Fig. 3Go).



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Fig. 3. Phylogenetic relationships of 46 Bacillaceae species inferred from the alignment of the 150 bp 3' end 16S rDNA and the 70 bp 5' 16S–23S ITS region. The rrnH allele of the 16S rRNA gene was used for Bacillus subtilis and Bacillus halodurans, respectively. The threshold value for groupings was Dmax=0·31. Bootstrap values (expressed as percentages of 100 replications) are shown at branch points; values greater than 50 % were considered significant. The bar represents the unit length of the number of nucleotide substitutions per site.

 
The resulting tree reveals 10 groups containing 45 Bacillaceae species and a single Bacillus species, Bacillus circulans, that remained ungrouped. These groups were defined as follows: when the maximal distance (Dmax; where distance D refers to the number of nucleotide substitutions per site) between species rooted at a common node was less than 0·31, these species were classified in the same group. The value of 0·31 was chosen as a threshold for grouping because it corresponds to the proportion of the length of the 16S–23S ITS used for sequence comparison to the total length of the DNA sequence used in the alignment (70 over 220 nt). With this threshold, species within a group could exhibit some nucleotide differences in their 5' 16S–23S ITS, but would confine the identities of their nucleotide sequence in the 3' end 16S rRNA coding region to almost perfect. Dmax values between species within each group are given in Table 1Go. Although each group allowed for the two most distant species to share a Dmax no greater than 0·31, the highest Dmax observed here was 0·24 for species within Group VIII. Clearly each group could contain more distant Bacillaceae species, as long as they share a Dmax up to 0·31. Presumably, other and new Bacillaceae species could be added on this phylogenetic tree and many could fall into one of these 10 existing groups.

Seven of the 10 groups were homogeneous. Groups II, V, VI and X contain seven, two, nine and five Bacillus species, respectively, exclusive of other genera. Bacillus subtilis, the Bacillus genus type species was found in Group VI. Group VII contains all six Brevibacillus species, exclusive of other genera. Likewise, Groups VIII and IX only contain six and three Paenibacillus species, respectively. The latter two groups originate from a single node and were later separated into two smaller branches using the grouping threshold value of 0·31. Both branches are within a Dmax value of 0·464.

In addition to Bacillus coagulans, Group I contains two Geobacillus species, Geobacillus stearothermophilus and Geobacillus kaustophilus. Interestingly, Priest et al. (1988)Go, using numerical phenetic data, also classified these three species in the same cluster. Two other clusters, Groups III and IV, each contained two Bacillaceae species from two different genera, Bacillus laevolacticus and Virgibacillus pantothenticus in Group III, and Bacillus badius and Marinibacillus marinus in Group IV. Whether both groups are heterogeneous as suggested by the different genera names is not clear. Bacillus laevolacticus in Group III and Marinibacillus marinus in Group IV were not included in the studies of Priest et al. (1988)Go and Ash et al. (1991)Go. When the genus Virgibacillus was created (Heyndrickx et al., 1998Go), Bacillus laevolacticus was not included in the study. Likewise, when the genus Marinibacillus was created (Yoon et al., 2001Go), Bacillus badius was not included in the analysis. It appears that the relationship between Bacillus laevolacticus and Virgibacillus pantothenticus (Group III), and between Bacillus badius and Marinibacillus marinus (Group IV) could still be open to debate.

Whereas the analysis of nucleotide identities in the 3' end 16S rDNA could distinguish Bacillaceae from other more distant bacterial taxa and distinguish between some Bacillaceae genera, additional analysis of nucleotide identities in the 5' 16S–23S ITS has added complementary information essential for further clustering of more closely related species. The present groupings based only on nucleotide identities in the 3' end 16S rDNA and 5' 16S–23S ITS are, in general, in agreement with current classifications based on series of phenetic and molecular data.

In the dendrogram presented here, the genus Bacillus still appears heterogeneous. Twenty-six Bacillus species are distributed in seven distinct groups (I, II, III, IV, V, VI and X), and a 27th, Bacillus circulans, is ungrouped. In contrast, the newly formed genera Brevibacillus and Paenibacillus are, respectively, more homogeneous. In addition, some Bacillus groups are quite distant from others as exemplified by Groups II and V with a Dmax value of 0·567. This is to be compared with a Dmax value of 0·459 between two different Bacillaceae genera, the Brevibacillus Group VII and the Paenibacillus Group IX. Interestingly, Dmax between both Paenibacillus Groups, VIII and IX, is 0·464. It would be worthwhile to further reassess the actual relatedness between the Bacillus species of the more distant groups to determine whether or not they are similar enough to be rightfully assigned to the same genus or whether the creation of novel genera would be warranted. If the latter holds true, a Dmax of 0·31, as used here, will prove useful not only at clustering Bacillaceae species, but also at suggesting the creation of novel genera.

It is noteworthy that in certain groups, some species were closely related with Dmax values less than 0·05. The species sharing a Dmax of 0·05 are indicated in Table 1Go. These species share a high proportion of identical nucleotides, not only over their 3' 16S rRNA coding region as expected, but also over their 5' 16S–23S ITS. In Group II, Bacillus psychrophilus and Bacillus psychrosaccharolyticus were within a Dmax of 0·035. The psychrophilic Bacillus species are all phenotypically related (Fox et al., 1992Go) and their taxonomy is based on a few discriminating properties (Larkin & Stokes, 1967Go; Abd El-Rahman et al., 2002Go). Although Bacillus psychrophilus has been unequivocally distinguished from Bacillus globisporus (Nakamura, 1984Go; Fox et al., 1992Go), the distinction between Bacillus psychrophilus and Bacillus psychrosaccharolyticus could still be open to debate. Both species, however, were located in different groups based on 16S rRNA sequences (Ash et al., 1991Go). In Group II, Bacillus simplex and ‘Bacillus maroccanus’, were within a Dmax of 0·011. Interestingly, Bacillus simplex and ‘Bacillus maroccanus’ share an almost identical 16S rRNA gene nucleotide sequence (Ash et al., 1991Go). Bacillus maroccanus’ is not a validly published name and whether Bacillus simplex and ‘Bacillus maroccanus belong to the same species could also still be open to debate. In Group VI, Bacillus amyloliquefaciens, Bacillus atrophaeus, Bacillus mojavensis and Bacillus subtilis were within a Dmax of 0·020. Likewise, these Bacillus subtilis-like bacteria are phenotypically very similar (Chun & Bae, 2000Go) and share almost identical 16S rRNA gene sequences (Ash et al., 1991Go). Bacillus fusiformis and Bacillus sphaericus were highly similar with Dmax values as low as 0·007. They are also very similar at the phenotypic level (Priest et al., 1988Go) and their 16S rRNA gene sequence is very homologous (Ash et al., 1991Go). In Group X, Bacillus anthracis, Bacillus cereus, Bacillus mycoides and Bacillus thuringiensis were also very similar with a Dmax value of 0·047. The phenotypic and genotypic similarities between all four species has been well documented (Logan & Berkeley, 1984Go; Claus & Berkeley, 1986Go; Ash et al., 1991Go). Recently, Helgason et al. (2000)Go proposed to regroup Bacillus anthracis, Bacillus cereus and Bacillus thuringiensis in a single species on the basis of genetic evidence. In Group VII, Brevibacillus brevis and Brevibacillus formosus were very close with a Dmax value of 0·025. The similarities between both species is well documented (Shida et al., 1995Go, 1996aGo, bGo). It is worth noting that Brevibacillus parabrevis isolates were originally classified as Brevibacillus brevis. They were later separated into two distinct species (Takagi et al., 1993Go). Strain ATCC 8264T was retained as the Brevibacillus brevis type strain. Strain ATCC 8186 was assigned to Brevibacillus parabrevis. In our study, the Dmax between both strains was nearly 0·1, in agreement with their separation into two species. In Group VIII, Paenibacillus gordonae and Paenibacillus validus share a Dmax value of 0·049, suggesting they might be the same species. Interestingly, both species have been proposed to be reclassified into a single species under the name Paenibacillus validus (Heyndrickx et al., 1995Go). As seen here, species separated by Dmax values within 0·05 are often phenotypically and genotypically very similar. The Dmax threshold of 0·05 may prove very useful in identifying species for which further analysis, including DNA–DNA reassociation, may be necessary to clarify whether or not their separation into different species was warranted.

The use of Dmax thresholds of 0·31 and 0·05, as used here for Bacillaceae classification, based only on a combination of a 150 bp sequence located at the 3' end of the 16S rRNA gene and a 70 bp sequence at the 5' end of the ITS, is a simple, rapid approach, suited to larger screening programs and easily accessible to most laboratories. It may reveal, in a different way, Bacillaceae species for which further characterization, including thorough phenotypic comparison, 16S rRNA sequence data and DNA–DNA hybridization, might be warranted for proper classification and/or reassignment at the genus or species level, respectively. Whether these Dmax thresholds may prove useful for other bacterial taxa as well remains to be assessed.


    ACKNOWLEDGEMENTS
 
We thank Kwang-Bo Joung for critical reading of the manuscript. We thank three anonymous referees and the Associate Editor for helpful comments.


    REFERENCES
 TOP
 ABSTRACT
 INTRODUCTION
 METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
Abd El-Rahman, H. A., Fritze, D., Spröer, C. & Clauss, D. (2002). Two novel psychrotolerans species: Bacillus psychrotolerans sp. nov. and Bacillus psychrodurans sp. nov. which contain ornithine in their cell walls. Int J Syst Evol Microbiol 52, 2127–2133.[Abstract]

Apirion, D. & Miczak, A. (1993). RNA processing in prokaryotic cells. Bioessays 15, 113–120.[CrossRef][Medline]

Ash, C., Farrow, A. E., Wallbanks, S. & Collins, M. D. (1991). Phylogenetic heterogeneity of the genus Bacillus revealed by comparative analysis of small-subunit-ribosomal RNA sequences. Lett Appl Microbiol 13, 202–206.

Ash, C., Priest, F. G. & Collins, D. (1993). Molecular identification of rRNA group 3 bacilli (Ash, Farrow, Wallbanks and Collins) using a PCR probe test. Proposal for the creation of a new genus Paenibacillus. Antonie van Leeuwenhoek 64, 253–260.[CrossRef][Medline]

Berg, K. L., Squires, C. & Squires, C. L. (1989). Ribosomal RNA operon anti-termination. Function of leader and spacer region box B-box A sequences and their conservation in diverse micro-organisms. J Mol Biol 209, 345–358.[CrossRef][Medline]

Bourque, S. N., Valero, J. R., Lavoie, M. C. & Levesque, R. C. (1995). Comparative analysis of the 16S to 23S ribosomal intergenic spacer sequences of Bacillus thuringiensis strains and subspecies and of closely related species. Appl Environ Microbiol 61, 1623–1626.[Abstract]

Chun, J. & Bae, K. S. (2000). Phylogenetic analysis of Bacillus subtilis and related taxa based on partial gyrA gene sequences. Antonie van Leeuwenhoek 78, 123–127.[CrossRef][Medline]

Claus, D. & Berkeley, R. C. W. (1986). Genus Bacillus Cohn 1872, 174AL. In Bergey's Manual of Systematic Bacteriology, vol. 2, pp. 1105–1139. Edited by P. H. A. Sneath, N. S. Mair, M. E. Sharpe & J. G. Holt. Baltimore: Williams & Wilkins.

Daffonchio, D., Borin, S., Consolandi, A., Mora, D., Manachini, P. L. & Sorlini, C. (1998a). 16S–23S rRNA internal transcribed spacers as molecular markers for the species of the 16S rRNA group I of the genus Bacillus. FEMS Microbiol Lett 163, 229–236.[Medline]

Daffonchio, D., Borin, S., Frova, G., Manachini, P. L. & Sorlini, C. (1998b). PCR fingerprinting of whole genomes: the spacers between the 16S and 23S rRNA genes and of intergenic tRNA gene regions reveal a different intraspecific genomic variability of Bacillus cereus and Bacillus licheniformis. Int J Syst Bacteriol 48, 107–116.[Abstract/Free Full Text]

de Silva, S., Petterson, B., de Muro, M. A. & Priest, F. G. (1998). A DNA probe for the detection and identification of Bacillus sporothermodurans using the 16S–23S rDNA spacer region and phylogenetic analysis of some field isolates of Bacillus which form highly heat resistant spores. Syst Appl Microbiol 21, 398–407.[Medline]

Felsenstein, J. (1989). PHYLIP-phylogeny inference package (version 2). Cladistics 5, 164–166.

Felsenstein, J. (2001). PHYLIP version 3.6a2. Distributed by the author. Department of Genetics, University of Washington, Seattle, WA, USA.

Fortina, M. G., Pukall, R., Schumann, P., Mora, D., Parini, C., Manachini, P. L. & Stackebrandt, E. (2001). Ureibacillus gen. nov., a new genus to accommodate Bacillus thermosphaericus (Andersson et al. 1995), emendation of Ureibacillus thermosphaericus and description of Ureibacillus terrenus sp. nov. Int J Syst Evol Microbiol51, 447–455.[Abstract]

Fox, G. E., Wisotzkey, J. D. & Jurtshuk, P., Jr (1992). How close is close: 16S rRNA sequence identity may not be sufficient to guarantee species identity. Int J Syst Bacteriol 42, 166–170.[Abstract/Free Full Text]

García-Martínez, J., Acinas, S. G., Antón, A. I. & Rodríguez-Valera, F. (1999). Use of the 16S–23S ribosomal genes spacer region in studies of prokaryotic diversity. J Microbiol Methods 36, 55–64.[CrossRef][Medline]

Goto, K., Omura, T., Hara, Y. & Sadaie, Y. (2000). Application of the partial 16S rDNA sequence as an index for rapid identification of species in the genus Bacillus. J Gen Appl Microbiol 46, 1–8.

Gürtler, V. & Stanisich, V. A. (1996). New approaches to typing and identification of bacteria using the 16S–23S rDNA spacer region. Microbiology 142, 3–16.[Free Full Text]

Helgason, E., Okstad, O. A., Caugant, D. A., Johansen, H. A., Fouet, A., Mock, M., Hegna, I. & Kolsto, A.-B. (2000). Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis – one species on the basis of genetic evidence. Appl Environ Microbiol 66, 2627–2630.[Abstract/Free Full Text]

Heyndrickx, M., Vandemeulebroecke, K., Scheldeman, P. & 7 others authors (1995). Paenibacillus (formerly Bacillus) gordonae (Pichinoty et al. 1986) Ash et al. 1994 is a later subjective synonym of Paenibacillus (formerly Bacillus) validus (Nakamura 1984Go) Ash et al. 1994: emended description of P. validus. Int J Syst Bacteriol 45, 661–669.[Abstract/Free Full Text]

Heyndrickx, M., Lebbe, L., Kersters, K., De Vos, P., Forsyth, G. & Logan, N. A. (1998). Virgibacillus: a new genus to accommodate Bacillus pantothenticus (Proom and Knight 1950). Emended description of Virgibacillus pantothenticus. Int J Syst Bacteriol 48, 99–106.[Abstract/Free Full Text]

Joung, K.-B. & Côté, J.-C. (2002). Evaluation of ribosomal RNA gene restriction patterns for the classification of Bacillus species and related genera. J Appl Microbiol 92, 97–108.[CrossRef][Medline]

Lane, D. J., Pace, B., Olsen, G. J., Stahl, D. A., Sogin, M. J. & Pace, N. R. (1985). Rapid determination of 16S ribosomal RNA sequences for phylogenetic analyses. Proc Natl Acad Sci U S A 82, 6955–6959.[Abstract/Free Full Text]

Larkin, J. M. & Stokes, J. L. (1967). Taxonomy of psychrophylic strains of Bacillus. J Bacteriol 94, 889–895.[Abstract/Free Full Text]

Liiv, A., Tenson, T., Margus, T. & Remme, J. (1998). Multiple functions of the transcribed spacers in ribosomal RNA operons. Biol Chem 379, 783–793.[Medline]

Logan, N. A. & Berkeley, R. C. W. (1984). Identification of Bacillus strains using the API system. J Gen Microbiol 130, 1871–1882.[Abstract/Free Full Text]

Nakamura, L. K. (1984). Bacillus psychrophilus sp. nov., nom. rev. Int J Syst Bacteriol 34, 121–123.

Nazina, T. N., Tourova, T. P., Poltaraus, A. B. & 8 other authors. (2001). Taxonomic study of aerobic thermophilic bacilli: descriptions of Geobacillus subterraneus gen. nov., sp. nov. and Geobacillus uzenensis sp. nov. from petroleum reservoirs and transfer of Bacillus stearothermophilus, Bacillus thermocatenulatus, Bacillus thermoleovorans, Bacillus kaustophilus, Bacillus thermoglucosidasius and Bacillus thermodenitrificans to Geobacillus as the new combinations G. stearothermophilus, G. thermocatenulatus, G. thermoleovorans, G. kaustophilus, G. thermoglucosidasius and G. thermodenitrificans. Int J Syst Evol Microbiol 51, 433–446.[Abstract]

Niimura, Y., Koh, E., Yanagida, F., Suzuki, K.-I., Komagata, K. & Kozaki, M. (1990). Amphibacillus xylanus gen. nov., sp. nov., a facultatively anaerobic sporeforming xylan-digesting bacterium which lacks cytochrome, quinone, and catalase. Int J Syst Bacteriol 40, 297–301.[Abstract/Free Full Text]

Nodwell, J. R. & Greenblatt, J. (1993). Recognition of boxA antiterminator RNA by the E. coli antitermination factors NusB and ribosomal protein S10. Cell 72, 261–268.[CrossRef][Medline]

Nour, M. (1998). 16S–23S and 23S–5S intergenic spacer regions of lactobacilli: nucleotide sequence, secondary structure and comparative analysis. Res Microbiol 149, 433–448.[Medline]

Page, R. D. M. (1996). TREEVIEW: an application to display phylogenetic trees on personal computers. Comput Appl Biosci 12, 357–358.[Free Full Text]

Pfeiffer, T. & Hartmann, R. K. (1997). Role of the spacer boxA of Escherichia coli ribosomal RNA operons in efficient 23S rRNA synthesis in vivo. J Mol Biol 265, 385–393.[CrossRef][Medline]

Pienta, P., Tang, J. & Cote, R. (1996). ATCC Bacteria and Bacteriophages, 19th edn. Rockville, MD, USA: American Type Culture Collection.

Priest, F. G., Goodfellow, M. & Todd, C. (1988). A numerical classification of the genus Bacillus. J Gen Microbiol 134, 1847–1882.[Abstract/Free Full Text]

Rössler, D., Ludwig, W., Schleifer, K. H., Lin, C., McGill, T. J., Wisotzkey, J. D., Jurtshuk, P., Jr & Fox, G. E. (1991). Phylogenetic diversity in the genus Bacillus as seen by 16S rRNA sequencing studies. Syst Appl Microbiol 14, 266–269.[Medline]

Sambrook, J., Fritsch, E. F. & Maniatis, T. (1989). Molecular Cloning: a Laboratory Manual, 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory.

Sanger, F., Nicklen, S. & Coulson, A. R. (1977). DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A 74, 5463–5467.[Abstract/Free Full Text]

Schlesner, H., Lawson, P. A., Collins, M. D., Weiss, N., Wehmeyer, U., Völker, H. & Thomm, M. (2001). Filobacillus milensis gen. nov., sp. nov., a new halophilic spore-forming bacterium with Orn-D-Glu-type peptidoglycan. Int J Syst Evol Microbiol 51, 425–431.[Abstract]

Shida, O., Takagi, H., Kadowaki, K., Udaka, S., Nakamura, L. K. & Komagata, K. (1995). Proposal of Bacillus reuszeri sp. nov., Bacillus formosus sp. nov., nom. rev., and Bacillus borstelensis sp. nov., nom. rev. Int J Syst Bacteriol 45, 93–100.[Abstract/Free Full Text]

Shida, O., Takagi, H., Kadowaki, K. & Komagata, K. (1996a). Proposal for two new genera, Brevibacillus gen. nov. and Aneurinibacillus gen. nov. Int J Syst Bacteriol 46, 939–946.[Abstract/Free Full Text]

Shida, O., Takagi, H., Kadowaki, K., Yano, H. & Komagata, K. (1996b). Differentiation of species in the Bacillus brevis group and the Bacillus aneurolyticus group based on the electrophoretic whole-cell protein pattern. Antonie van Leeuwenhoek 70, 31–39.[CrossRef][Medline]

Stephen, D., Jones, C. & Schofield, J. P. (1990). A rapid method for isolating high quality plasmid DNA suitable for DNA sequencing. Nucleic Acids Res 18, 7463–7464.[Free Full Text]

Takagi, H., Shida, O., Kadowaki, K., Komagata, K. & Udaka, S. (1993). Characterization of Bacillus brevis with descriptions of Bacillus migulanus sp. nov., Bacillus choshinensis sp. nov., Bacillus parabrevis sp. nov., and Bacillus galactophilus sp. nov. Int J Syst Bacteriol 43, 221–231.[Abstract/Free Full Text]

Thompson, J. D., Higgins, D. G. & Gibson, T. J. (1994). CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Res 22, 4673–4680.[Abstract/Free Full Text]

Wainø, M., Tindall, B. J., Schumann, P. & Ingvorsen, K. (1999). Gracilibacillus gen. nov., with description of Gracilibacillus halotolerans gen. nov., sp. nov.; transfer of Bacillus dipsosauri to Gracilibacillus dipsosauri comb. nov., and Bacillus salexigens to the genus Salibacillus gen. nov., as Salibacillus salexigens comb. nov. Int J Syst Bacteriol 49, 821–831.[Abstract/Free Full Text]

Weisburg, W. G., Barns, S. M., Pelletier, D. A. & Lane, D. J. (1991). 16S ribosomal DNA amplification for phylogenetic study. J Bacteriol 173, 697–703.[Abstract/Free Full Text]

Wisotzkey, J. D., Jurtshuk, P., Jr, Fox, G. E., Deinhard, G. & Poralla, K. (1992). Comparative sequence analyses on the 16S rRNA (rDNA) of Bacillus acidocaldarius, Bacillus acidoterrestris, and Bacillus cycloheptanicus and proposal for creation of a new genus, Alicyclobacillus gen. nov. Int J Syst Bacteriol 42, 263–269.[Abstract/Free Full Text]

Woese, C. (1987). Bacterial evolution. Microbiol Rev 51, 221–271.[Free Full Text]

Yoon, J.-H., Weiss, N., Lee, K.-C., Lee, I.-S., Kang, K. H. & Park, Y.-H. (2001). Jeotgalibacillus alimentarius gen. nov., sp. nov., a novel bacterium isolated from jeotgal with L-lysine in the cell wall, and reclassification of Bacillus marinus Rüger 1983 as Marinibacillus marinus gen. nov., comb. nov. Int J Syst Evol Microbiol 51, 2087–2093.[Abstract]




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