Search results for "numerical taxonomy"
showing 10 items of 12 documents
Patterns of the lemma micromorphology : a useful tool in taxonomy of the middle Asian Eragrostis species (Poaceae)
2017
We examined all taxa of the genus Eragrostis noted so far in Middle Asia, namely: Eragrostis amurensis, Eragrostis cilianensis, Eragrostis minor agg., Eragrostis pilosa and Eragrostis virescens. By means of scanning electron microscope, such structures as long cells, short cells (cork and silica cells), prickles, microhairs and glands were scrutinized and compared among taxa. Additionally, several macromorphological characteristics were investigated. Principal component analysis and cluster analysis were conducted in order to reveal the morphological relationships and differences among species. Micromorphology of the lemma epidermis, together with selected macromorphological characteristics…
Pseudomonas salomonii sp. nov., pathogenic on garlic, and Pseudomonas palleroniara sp. nov., isolated from rice
2002
International audience; A total of 26 strains, including 15 strains isolated from garlic plants with the typical symptoms of 'Café au lait' disease and 11 strains isolated from diseased or healthy rice seeds and sheaths infested by Pseudomonas fuscovaginae, were compared with 70 type or reference strains of oxidase-positive pathogenic or non-pathogenic fluorescent pseudomonads. The strains were characterized by using a polyphasic taxonomic approach. Numerical taxonomy of phenotypic characteristics showed that the garlic and rice strains were related to each other. However, they clustered into separate phenons, distinct from those of the other strains tested, and were different in several nu…
A classification of European skulls from three time periods.
1987
We analyze the taxonomic structure of European populations at three time periods, the Early Middle Ages, the Late Middle Ages and the Recent Period. The data consist of sample means for 10 cranial variables based on 137, 108, and 183 samples for the three periods. Clustering by standard numerical taxonomic procedures reveals that the data are represented only poorly as hierarchic classifications. The clusters form significant and moderately strong associations with an arrangement of the samples by regions (geography) and by language family. Whereas during the early period, language family showed a stronger association with clusters based on cranial morphology, in the recent populations thes…
Taxonomic study of sucrose-positive Aeromonas jandaei-like isolates from faeces, water and eels: emendation of A. jandaei Carnahan et al. 1992
2003
Fourteen sucrose-positive Aeromonas jandaei-like isolates from fresh water and reared European eels were subjected to a polyphasic study to determine their taxonomic position. Numerical taxonomy was used to analyse phenotypic data obtained for these isolates and 43 type and reference strains representative of recognized Aeromonas species. The A. jandaei cluster (phenon 1) was defined at 81.6 % similarity (S(J)); this included the A. jandaei-like isolates, the sucrose-positive strain Aeromonas veronii biogroup sobria CECT 4910 and nearly all A. jandaei reference strains used in the study. Four other reference strains of A. veronii biogroup sobria and the type strain of Aeromonas ichthiosmia …
Phenotypic study by numerical taxonomy of strains belonging to the genus Aeromonas.
2002
Aims: This study was undertaken to cluster and identify a large collection of Aeromonas strains. Methods and Results: Numerical taxonomy was used to analyse phenotypic data obtained on 54 new isolates taken from water, fish, snails, sputum and 99 type and reference strains. Each strain was tested for 121 characters but only the data for 71 were analysed using the `SSM' and `SJ' coefficients, and the UPGMA clustering algorithm. At SJ values of ≥ 81·6% the strains clustered into 22 phenons which were identified as Aer. jandaei, Aer. hydrophila, Aer. encheleia, Aer. veronii biogroup veronii, Aer. trota, Aer. caviae, Aer. eucrenophila, Aer. ichthiosmia, Aer. sobria, Aer. allosaccharophila, Ae…
Taxonomy and phenetic relationships ofElectrogena affinis(Eaton, 1883) (Ephemeroptera : Heptageniidae)
1999
Electrogena affinis est redecrite a tous les stades du cycle de developpement. Les larves ont ete etudiees et comparees aux autres especes europeennes du meme genre sur des caracteres de diagnose standard qui, dans des precedents travaux, se sont montres tres utiles pour la taxonomie d'Electrogena. Le statut d'E. fascioculata est discute et la synonymie E. fascioculata = E. affinis est etablie. Finalement, les liaisons phenetiques entre E. affinis et d'autres especes europeennes voisines sont examinees par une analyse de groupes sur la base de caracteres quantitatifs des larves.
Numerical Taxonomy of Aerobic, Gram-negative Bacteria associated with Oysters and Surrounding Seawater of the Mediterranean Coast
1995
Abstract A numerical taxonomic study was performed on 245 strains of heterotrophic, aerobic, marine bacteria, plus 26 reference strains. The isolates were obtained from oysters and seawater sampled monthly over one year, by direct plating on Marine Agar. The strains were characterised by 93 morphological, biochemical, physiological and nutritional tests. Clustering yielded 46 phena at 0.60 S level (S J coefficient). Some could be identified as species of Alteromonas, Shewanella, Deleya, Flavobacterium, Oceanospirillum, Pseudomonas and marine Agrobacterium -like organisms, others were unidentified groups. Several phena seem to correspond to as yet undescribed taxa.
Numerical Taxonomy of Vibrionaceae Isolated from Oysters and Seawater Along an Annual Cycle
1994
Summary A numerical taxonomic study on Gram negative heterotrophic facultative anaerobic bacteria isolated from marine samples (oysters and seawater of Western Mediterranean Sea) was performed. Three hundred sixty eight strains, including reference strains of most species of the Vibrionaceae , were characterized (96 tests per strain). Cluster analysis of similarity matrices obtained with S SM and S J coefficients was performed and S J -based tree and 0.75 S level selected for definition of phena. Larger phena corresponded to non-luminescent Vibrio splendidus biotype 1 and V. harveyi . The species V. tubiashii (an oyster larvae pathogen), V. pelagius, V. mediterranei, V. orientalis and Photo…
Genetic Diversity of Rhizobia Isolated from the Legume Genera Astragalus, Oxytropis and Onobrychis
1998
The legume genera Astragalus and Oxytropis belong to the tribe Galegae. These legumes are common in Arctic and Temperate climatic zones. Previous studies based on cross-inoculation experiments and numerical taxonomy (Prevost et al., 1987; Novikova et al., 1993; 1994) suggested that the rhizobia associated with these legumes were closely related. Also the legume species Onobrychis viciifolia (sainfoin, tribe Hedysareae) was effectively nodulated by rhizobia isolated from Astragalus and Oxytropis spp. (Prevost et al., 1987). Rhizobia isolated from A. sinicus were classified in a new species, Mesorhizobium huakuii, (Chen et al., 1991; Jarvis et al., 1997). Other rhizobia from Astragalus and Ox…
Numerical Taxonomy of Pseudomonads Isolated from Water, Sediment and Eels
1992
Summary A numerical taxonomic study was performed on 129 pseudomonad isolates from aquatic environments. 67 out of 98 field strains were isolated from water and sediment samples from Albufera lake, a hypereutrophic lake near Valencia, and 31 strains came from an eel hatchery. 10 clusters were formed at 84% similarity level when the Sokal-Michener similarity coefficient was used. Five clusters were designated as Pseudomonas putida (16 strains), P. fluorescens biotype I (9 strains), P. pseudoalcaligenes (11 strains), P. stutzen (4 strains) and Shewanella putrefaciens (3 strains). A subcluster of 7 strains (out of 15) was ascribed to the species Xanthomonas maltophilia , while the other strain…