Summary: One hundred and nineteen strains of alkaliphilic and alkalitolerant, aerobic endospore-forming bacteria were examined for 47 physiological and biochemical characters, and DNA base composition. Numerical analysis (S
J and S
SM/UPGMA clustering) revealed 11 clusters that comprised three or more strains. Most of the phena were further characterized by analysis of carbohydrate utilization profiles using the API 50CH system, but strains of two taxa could not be cultured by this method. DNA reassociation studies showed that nine of the phena were homogeneous, but strains of phenon 4 and phenon 8 were each subdivided into two DNA hydridization groups. The strains could therefore be classified into 13 taxa plus a number of unassigned single-membered clusters. Two taxa were equated with Bacillus cohnii and B. alcalophilus and nine of the remainder are proposed as new species with the following names: B. agaradhaerens sp. nov., B. clarkii sp. nov., B. clausii sp. nov., B. gibsonii sp. nov., B. halmapalus sp. nov., B. halodurans comb, nov., B. horikoshii sp. nov., B. pseudalcalophilus sp. nov. and B. pseudofirmus sp. nov. Two taxa were insufficiently distinct to allow confident identification and these have therefore not been proposed as new species.

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Phenetic diversity of alkaliphilic Bacillus strains: proposal for nine new species

We determined the degree of binding between deoxyribonucleic acid (DNA) preparations from representative rhodococci and thymine-labeled DNAs (derived from labeled uracil) from the following six reference strains: Rhodococcus coprophilus (Approved Lists, 1980) strain N744, R. corallinys (Bergey et al. 1923) Goodfellow and Alderson 1979 (Approved Lists, 1980) strain N657, R. equi (Approved Lists, 1980) strain C7, R. rhodochrous (Approved Lists, 1980) strain N54, R. ruber (Approved Lists, 1980) strain N361, and R. rubropertinctus (Hefferan 1904) Goodfellow and Alderson 1979 (Approved Lists, 1980) strain N4. Although the congruence between the DNA reassociation and earlier numerical phenetic data was good, there was evidence that some strains had been misclassified in the numerical phenetic study. In particular, strains labeled R. corallinus (including the type strain of R. corallinus) and R. rubropertinctus belonged to a single DNA homology group. The former name is thus a later, subjective synonym of the latter. The guanine plus cytosine contents of the DNAs of the rhodococci fell within the range of 65 to 73 mo1%.

Deoxyribonucleic Acid Reassociation in the Classification of the Genus Rhodococcus Zopf 1891 (Approved Lists, 1980)

Past, present and future of the boundaries of the Pseudomonas genus: Proposal of Stutzerimonas gen. Nov

Numerical taxonomy of staphylococci

There is an anthropocentric tendency to treat the terms sex and reproduction as synonymns. In fact, however, reproduction-that is, the perpetuation of the species-does not necessarily demand the biochemically expensive differentiation of organisms into male and female. The fact that sexuality is so common among so many forms of life is thus striking testimony to the overriding success of DNA transfer as an adaptive strategy in evolution. A prime reason for the widespread occurrence of sexual DNA exchange mechanisms is the selective advantage which seems to arise from the presence of DNA's of different genetic pedigrees in the same cell. It is, therefore, something of a paradox that evolution results in the continuing emergence of new species which are defined by their inability to interbreed. Speciation has the consequence that, as a population evolves, its members are increasingly screened off from the genetic experience of other organisms in the same ecosystem. This can result in a highly uneconomic situation in which species X is forced to re-evolve "from scratch" a gene already present in an adjacent species Y. This paradox raises a question central to evolutionary theory: Once any two

https://www.jstor.org/stable/pdfplus/1297633.pdf

R. R. Colwell

Papers

Application of Molecular Genetics and Numerical Taxonomy to the Classification of Bacteria