- Volume 51, Issue 4, 2001

The genus Bartonella comprises two human-specific pathogens and a growing number of zoonotic or animal-specific species. Domesticated as well as wild mammals can serve as reservoir hosts for the zoonotic agents and transmission to humans may occur by blood sucking arthropods or by direct blood to blood contact. Humans may come into intimate contact with free-ranging mammals during hunting, especially during evisceration with bare hands, when accidental blood to blood contact frequently occurs. The objective of this work was to determine the presence and the polymorphism of Bartonella strains in wild roe deer (Capreolus capreolus) as the most widely spread game in Western Europe. We report the isolation of four Bartonella strains from the blood of five roe deer. These strains carry polar flagella similar to Bartonella bacilliformis and Bartonella clarridgeiae. Based on their phenotypic and genotypic characteristics, three of the four roe deer isolates were different and they were all distinct from previously described Bartonella species. They can be distinguished from each other and from other Bartonella species by their protein profile, ERIC-PCR pattern, 16S rRNA and citrate synthase (gitA) gene sequences, as well as by whole DNA-DNA hybridization. In spite of their considerable heterogeneity, all four strains fulfil the criteria for belonging to a single new species. The name Bartonella schoenbuchii is proposed for this new species. The type strain R1T of Bartonella schoenbuchii has been deposited in the National Collection of Type Cultures as NCTC 13165T and the Deutsche Sammlung von Mikroorganismen und Zellkulturen as DSM 13525T.

A polyphasic taxonomic approach was used to study atypical enterococci isolated from surface waters. All strains were characterized by physiological and biochemical tests as well as by genotyping. The results of biochemical tests and tRNA intergenic length polymorphism analysis (tDNA-PCR) divided all studied strains uniformly into two groups. Because these groups were clearly separated from all enterococcal species described to date, 16S rDNA sequence analysis, DNA base composition analysis and DNA-DNA hybridization of representative strains were done to elucidate the taxonomic position of the analysed groups. On the basis of the results obtained, the names Enterococcus haemoperoxidus (type strain CCM 4851T = LMG 19487T) and Enterococcus moraviensis (type strain CCM 4856T = LMG 19486T) are proposed for the two hitherto undescribed species. The type strains and reference cultures have been deposited in the Czech Collection of Microorganisms (CCM), Masaryk University, Brno, Czech Republic, and in the BCCM/LMG Culture Collection, Ghent University, Belgium.

Phylogenetic analysis of the genera within the suborder Pseudonocardineae based on almost complete sequences of 16S rDNA showed that Saccharothrix cryophilis NRRL B-16238T was misplaced within the genus Saccharothrix. Saccharothrix cryophilis NRRL B-16238T appeared to be phylogenetically closest to Streptoalloteichus, but is morphologically distinct from this genus because sporangia with motile spores are not observed. The aerial mycelium fragments into rod-shaped elements and sclerotium-like bodies are observed occasionally in the substrate mycelium. The cell wall contains meso-diaminopimelic acid, whole-cell hydrolysates contain galactose, rhamnose and ribose, the phospholipid pattern is type PIV and the principal menaquinone is MK-9(H4). A new genus to accommodate Saccharothrix cryophilis is proposed, Crossiella gen. nov., in recognition of the contributions of Thomas Cross, a distinguished actinomycete biologist at the University of Bradford, UK. The type species is Crossiella cryophila gen. nov., comb. nov.

18S rDNA sequences of six Naviculaceae species [Amphora montana, Gomphonema parvulum, Eolimna minima (syn. Navicula minima), Eolimna subminuscula (syn. Navicula subminuscula), Navicula veneta and Phaeodactylum tricornutum] were determined in order to assess the monophyly of this important group of diatoms, to date not included in 18S rDNA databases, and also that of the recently described genus Eolimna. Phylogenetic trees were constructed using other known diatom 18S rDNA sequences, and best tree topologies obtained were tested against alternative trees for their reliability. The analyses do not reject the monophyly of Naviculaceae and strongly support the separation of the genus Eolimna from Navicula sensu lato. The two species of Eolimna, however, do not appear to be each other's closest relatives among the species investigated: rather, E. subminuscula shows affinities to A. montana, and E. minima to P. tricornutum. A. montana, a species which it has been proposed should be transferred into a separate taxon from the other five species, was found to have grouped well within them in all analyses.

Ciliates are defined by the presence of dimorphic nuclei. Following conjugation, both the functional macronucleus (MAC) and the transcriptionally inactive germline micronucleus (MIC) develop from a zygotic nucleus. As the MAC develops, germline chromosomes are processed by excision of internal sequences, fragmentation and amplification of the remaining chromosomes. The extent of processing varies among lineages and, in all but one class of ciliates, the resulting MACs divide by an unusual process termed 'amitosis'. Research on these chromosomal rearrangements, largely from studies of only a handful of taxa from two of the nine classes of ciliates, has failed to find evidence of homologous processing among ciliate lineages. This observation, coupled with the structural diversity of MAC genomes among ciliates, led to the hypothesis of multiple origins of at least two MAC properties: (1) the ability to divide and (2) the mechanisms underlying chromosomal processing. Applying this logic to a more inclusive analysis of ciliate lineages, where an even greater diversity of MAC structure is observed, increases the potential number of origins of these MAC characteristics. Here, it is proposed that a single origin of a relatively plastic mechanism underlying MAC development better explains the observed diversity in MAC structure and processing among ciliates. Such a mechanism is suggested by the demonstration of epigenetic effects during MAC development in Paramecium and Tetrahymena.

The actin gene has been studied as a potential phylogenetic marker for selected members of the anamorphic genus Candida and seven related teleomorphic genera (Debaryomyces, Issatchenkia, Kluyveromyces, Saccharomyces and Pichia from the Saccharomycetaceae; Clavispora and Metschnikowia from the Metschnikowiaceae). The nucleotide sequences of 36 fungal taxa were analysed with respect to their molecular evolution and phylogenetic relationships. A total of 460 bp (47%) of the coding 979 bp were variable and 396 bp (40%) of these were found to be phylogenetically informative. Further analysis of the sequences showed that the genic G+C contents were higher than the nuclear G+C contents for most of the taxa. A strong positive correlation was found between G+C content over all codon positions and third positions. First and second codon positions were considered to be independent of the genic G+C content. The expected transition/transversion bias was detected only for third positions. Pairwise comparisons of transitional and transversional changes (substitutions) with total percentage sequence divergences revealed that the third position transitions showed no saturation for ingroup comparisons. A specific weighting scheme was set up, combining codon-position weights with change-frequency weights to enable the inclusion of distant outgroup taxa. Parsimony analyses of the investigated taxa showed four groups, three of which corresponded to major clusters that had been established previously in Candida by rDNA analysis. Interrelationships among the species groups in this heterogeneous anamorphic genus were determined. The polyphyletic origin of the selected Candida species and their close associations with several ascomycete genera were verified and known anamorph/teleomorph pairs confirmed. The actin gene was established as a valuable phylogenetic marker with the particular advantage of an unambiguous alignment.

The lager brewing yeasts, Saccharomyces pastorianus (synonym Saccharomyces carlsbergensis), are allopolyploid, containing parts of two divergent genomes. Saccharomyces cerevisiae contributed to the formation of these hybrids, although the identity of the other species is still unclear. The presence of alleles specific to S. cerevisiae and S. pastorianus was tested for by PCR/RFLP in brewing yeasts of various origins and in members of the Saccharomyces sensu stricto complex. S. cerevisiae-type alleles of two genes, HIS4 and YCL008c, were identified in another brewing yeast, S. pastorianus CBS 1503 (Saccharomyces monacensis), thought to be the source of the other contributor to the lager hybrid. This is consistent with the hybridization of S. cerevisiae subtelomeric sequences X and Y' to the electrophoretic karyotype of this strain. S. pastorianus CBS 1503 (S. monacensis) is therefore probably not an ancestor of S. pastorianus, but a related hybrid. Saccharomyces bayanus, also thought to be one of the contributors to the lager yeast hybrid, is a heterogeneous taxon containing at least two subgroups, one close to the type strain, CBS 380T, the other close to CBS 395 (Saccharomyces uvarum). The partial sequences of several genes (HIS4, MET10, URA3) were shown to be identical or very similar (over 99%) in S. pastorianus CBS 1513 (S. carlsbergensis), S. bayanus CBS 380T and its close derivatives, showing that S. pastorianus and S. bayanus have a common ancestor. A distinction between two subgroups within S. bayanus was made on the basis of sequence analysis: the subgroup represented by S. bayanus CBS 395 (S. uvarum) has 6-8% sequence divergence within the genes HIS4, MET10 and MET2 from S. bayanus CBS 380T, indicating that the two S. bayanus subgroups diverged recently. The detection of specific alleles by PCR/RFLP and hybridization with S. cerevisiae subtelomeric sequences X and Y' to electrophoretic karyotypes of brewing yeasts and related species confirmed our findings and revealed substantial heterogeneity in the genome constitution of Czech brewing yeasts used in production.