Search results for "Systematic"
showing 10 items of 7608 documents
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…
Life-history constraints and warning signal expression in an arctiid moth
2007
Summary 1 Traditionally, large pattern elements in conspicuous warning signals are assumed to be selected by predation because increasing signal strength enhances education and avoidance of predators. However, variation in the colour pattern of a warningly coloured species often exists even within a location, and many warning signals have relatively small pattern elements. This suggests that there must be opposing selection pressures that can constrain warning signal expression, resulting in variation in warning signals as well as suboptimal signals for predator education. 2 We quantified the variation in the warning signal of Parasemia plantaginis-moth larvae. With a full-sib rearing exper…
Effects of environmental factors on seed germination ofAnthyllis barba-jovisL
2008
Abstract The influence of the main environmental factors on seed germination of Anthyllis barba-jovis L. were analysed. This work is part of a broader investigation aimed at the reintroduction of this species on Mount Conero, Ancona (central Italy), where it is at present extinct. The seeds were collected from the Gargano headland (southern Adriatic coast). Experimental analyses were carried out to determine: (i) dormancy levels of seeds collected in successive years, and also collected from the soil seed bank; (ii) effects of usual pre-treatments for overriding the physical dormancy of the seeds; (iii) optimal temperature range for maximum germination; (iv) effects of fire on seed germinat…
Global warming affect Collembola community: A long-term study
2006
Summary Long-term (1992–2002) effects of climate changes on soil Collembola in Scots pine Pinus sylvestris forests in North Vidzeme Biosphere Reserve (northern Latvia) are investigated. The study was carried out in three forest stands of different age, young (30–40 years), middle aged (50–70 years), and old (150–200 years). One hundred soil samples were collected within each sampling site once a year in autumn over a period of 11 years. In total, 66 species of Collembola were found. Species richness varied between 47 and 56 and density of Collembola from 7300 to 8300 ind m−2. A statistically significant increase in the sums of positive air temperatures (⩾4 °C) was recorded during the period…
Scuteparvin, a new neoclerodane diterpenoid from Scutellaria parvula
2004
Abstract The diterpenoid fraction occurring in the acetone extract of the aerial parts of Scutellaria parvula has been investigated. Only one neoclerodane diterpenoid, scuteparvin, was isolated and its structure elucidated as 4α,18-epoxy-6α- trans -cinnamoyloxy- neo clerod-13-en-15,16-olide, a new natural product. Scuteparvin is quite similar to the already known ajugarin V from Ajuga remota , the only difference being the occurrence of a trans -cinnamoyl ester system instead of an acetate on the 6α-OH group. This finding confirms that the genera Scutellaria and Ajuga are closely related taxonomically.
SELFING ABILITY AND MALE STERILITY IN SENECIO VERNALIS WALDST. ET KIT. (ASTERACEAE) FROM ISRAEL
1994
Two major findings relating to the breeding system of Senecio vernalis from Israel are reported. First, isolation experiments failed to confirm the existence of a widespread, truly self-compatible and predominantly self-pollinating breeding system in Israeli populations of S. vernalis. However, a single S. vernalis plant derived from a natural stand at Jerusalem was found to be self- compatible and strongly self-pollinating. In its progeny, there were signs of inbreeding depression commonly associated with selfed offspring of outbreeding species. Selfing ability ratios in this progeny indicate a single dominant gene for selfing ability in S. vernalis. The implications of these observations …
Epimerization, oxidation and reduction of bile acids by Eubacterium lentum
1984
Summary Twenty-eight strains of Eubacterium lentum were divided into five groups on the basis of their ability to metabolize cholic acid and dehydrocholic acid: (I) Strains with 3α- and 3/β-dehydrogenating activities (1 strain), (II) strains with 12α-dehydrogenating activity (5 strains), (III) strains with 3α-, 3β-, 7α-, and 12α-dehydrogenating activities (8 isolates), (IV) transition stages between group II and III (1 strain), (V) strains devoid of any measurable bile acid metabolizing activities or with only trace activities (11 isolates). Using appropriate bile acids it was demonstrated that hydroxyl or keto groups at positions C 3 , C 7 , and C 12 did not influence bile acid transformat…
New Light on Parasorex Depereti (Erinaceomorpha: Erinaceidae: Galericini) from the Late Messinian (MN 13) of the Monticino Quarry (Brisighella, Faenz…
2019
Abstract A large-sized species of Parasorex is common in the MN 13 mammal assemblages from the uppermost Messinian sandy-marly fissure fillings within the Gessoso Solfifera Formation at Brisighella (Northern Apennine). This erinaceid has been classified as Galerix sp. in the first papers on the Brisighella fauna. Later, it was described in detail in an unpublished Ph.D. dissertation by Fanfani (1999), who referred it to Galerix depereti. Van den Hoek Ostende (2001) included G. depereti in the genus Parasorex, Parasorex depereti has been described by Crochet (1986) on scarce material from a few Early Pliocene (MN 14–15) localities of southern France and Spain. Parasorex cf. depereti has been…
The taxonomic position of Roesleria subterranea
2006
The genus Roesleria was introduced with the single species Roesleria hypogaea (current name: R. subterranea) by Thümen in 1877. The species was originally described from roots of grapevine and recognised as a facultative root-rotting parasite. The mazaediate ascoma with evanescent asci led to the assumption that Roesleria would be an ally of mazaediate lichens. In this study we calculate 28S, 18S as well ITS1-5.8S-ITS2 rDNA phylogenies. These data indicate that Roesleria is closely related to Hymenoscyphus (Helotiales). In contrast to other members of the Helotiales, the ascospores of Roesleria are passively released, and a distinct apical apparatus cannot be observed by LM. Electron optic …
<strong>Pamphagidae (Orthoptera: Caelifera) of North Africa: key to genera and the annotated check-list of species</strong>
2013
At least 95 species of Pamphagidae belonging to 17 genera are known in North Africa. Taxonomic status is fairly known, with some exception, mainly due to scarcity of available specimens of some genera in museums and collections. In this paper, the author proposes a new key to genera and reports the annotated list of all the known species, based on specimens examined in different European museums. Concerning the subfamily Thrinchinae, he proposes to consider only the following species of the genus Tmethis: T. cisti, T. harterti new status, T. maroccanus and T. pulchripennis. He also considers Neotmethis bidentatus synonym of T. harterti, and the three newly described species of the genus Tua…