Search results for "Theca"
showing 10 items of 49 documents
On six new species of Zygophylax Quelch, 1885 (Cnidaria, Hydrozoa, Zygophylacidae) from the New Calendonian region.
2020
Six new species of Zygophylax (Z. dispersa sp. nov., Z. encarnae sp. nov., Z. laertesi sp. nov., Z. medeae sp. nov., Z. niobae sp. nov. and Z. pseudoabietinella sp. nov.) are described and figured. The material studied was present in collections from several French expeditions in the western Pacific, mostly in the waters around New Caledonia and vicinity.
Two new Antarctic species of Schizotricha (Cnidaria: Hydrozoa: Leptothecata) from US Antarctic expeditions
2004
Two species of the genus Schizotricha new to science (Schizotricha crassa sp. nov. and S. southgeorgiae sp. nov.) have been studied. Both species are described and figured and their systematic position amongst the remaining species of the genus is discussed. The material was collected during the United States Antarctic Research Programme (USARP) with RV 'Eltanin' and RV 'Islas Orcadas'. A comparative table listing the main features and distribution of the known species of Schizotricha, together with an identification key, are presented.
Breaking molds: Oswaldella laertesi, sp. nov., a unique Antarctic species of Oswaldella Stechow, 1919 (Cnidaria: Hydrozoa: Kirchenpaueriidae)
2007
A new species of the Antarctic genus Oswaldella Stechow is described and figured, and its position amongst the remaining species of the genus is discussed. The material was collected from the Ross Sea area (Antarctica) during the BioRoss survey of the western Ross Sea and Balleny Islands in 2004. Oswaldella laertesi, sp. nov., is unique amongst known species of the genus in having hydrocladia arranged in three longitudinal rows.
Molecular characterization of the leucine cluster in Buchnera PSY, primary endosymbiont of the aphid Pemphigus spyrothecae
2002
ABSTRACT Buchnera strains from most aphid subfamilies studied to date have been found to carry the leucine gene cluster ( leuA , - B , - C , and - D ) on a plasmid, an organization unique among bacteria. Here, however, we demonstrate a classical chromosomal location of the cluster in Buchnera sp. strain PSY from the aphid Pemphigus spyrothecae (subfamily Pemphiginae). The genes that flank leuABCD in Buchnera sp. strain PSY appear to be adjacent in the genome of Buchnera sp. strain APS, a strain carrying a leucine plasmid. We propose that the presence of a leucine plasmid predates the diversification of symbiotic Buchnera and that the chromosomal location observed in Buchnera sp. strain PSY …
Zwei wiederentdeckte Briefe Niebuhrs und ein anonymer Aufsatz in der 'Allgemeinen Literatur-Zeitung'
2012
In the archives of the Berlin-Brandenburgische Akademie der Wissenschaften two letters by Barthold Georg Niebuhr of September 1816 are preserved which have never been published in a scholarly edition. The present transcription of the text is diplomatical. Furthermore the letters are examinated in their historical context. The use made of these letters in an anonymous publication in the same year in the Allegmeine Literatur-Zeitung is also discussed.
Corb. (), new to the Italian bryoflora
1999
Abstract Fossombronia crozalsii Corb. ( Codoniaceae ) was recently found on the island of Linosa (Pelagian Islands, Sicily). The species is new for the Italian bryological flora, enlarging the area of distribution of this species in the Mediterranean basin. Fossombronia crozalsii was found on volcanic soil associated with other interesting and rare hepatics, in particular Exormotheca pustulosa Mitt. Finally, for both species some ecological and phytogeographical considerations related to their presence in the Mediterranean basin are discussed.
Ring test for whole-sediment toxicity assay with -a- benthic marine diatom
2009
7 páginas, 3 figuras, 3 tablas.
Intraovarian regulation of gonadotropin-dependent folliculogenesis depends on notch receptor signaling pathways not involving Delta-like ligand 4 (Dl…
2013
Background In-situ hybridisation studies demonstrate that Notch receptors and ligands are expressed in granulosa cells (GCs) and in the theca layer vasculature of growing follicles. Notch signaling involves cell-to-cell interaction mediated by transmembrane receptors and ligands. This signaling pathway may represent a novel intraovarian regulator of gonadotropin-dependent follicular development to the preovulatory stage. We hypothesized that blocking Notch pathways would disrupt follicular maturation in the mouse ovary. Methods Hypophysectomized CD21 female mice were administered pregnant mare serum gonadotropin (PMSG) for 3 days to stimulate follicular development. In one experiment, a pan…
Revision of the genus Filellum Hincks, 1868 (Lafoeidae, Leptothecata, Hydrozoa)
2011
A taxonomic review of the cosmopolitan genus Filellum was performed considering morphology, morphometry and cnidome. Species for which we had access to materials were redescribed and morphologically characterized based on optical and scanning electron microscopy (SEM). The materials examined belong to museum collections, including type specimens. All records found in the literature were checked. Our analyses confirmed the validity of 10 out of the 18 nominal species referred to the genus, and established four others (F. adnatum, F. bouvieri, F. contortum and F. plicatum) as species inquirenda. A new species, Filellum bouvetensis sp. nov., is described. The species Reticularia annulata Watso…
Genetic evidence confirms polygamous mating system in a crustacean parasite with multiple hosts.
2014
Mating systems are diverse in animals, notably in crustaceans, but can be inferred from a limited set of parameters. Baeza and Thiel (2007) proposed a model predicting mating systems of symbiotic crustaceans with three host characteristics and the risk of predation. These authors proposed five mating systems, ranging from monogamy to polygynandry (where multiple mating occurs for both genders). Using microsatellite loci, we tested the putatively mating system of the ectoparasite crab Dissodactylus primitivus. We determined the mating frequencies of males and females, parentage assignment (COLONY & GERUD software) as well as the contents of female spermathecae. Our results are globally consi…