Search results for " Systematics."
showing 10 items of 4820 documents
Alterations inras-gene expression and intracellular distribution of protein kinase C in the spongeGeodia cydonium in response to marine pollution
1990
The siliceous spongeGeodia cydonium Jameson was used to study the influence of pollution in marine environments on selected parameters of the intracellular signal transduction pathway. The parameters chosen were: intracellular distribution of protein kinase C (PK-C),ras-gene expression and DNA polymerasealpha (DNA Polalpha) activity. Both PK-C andras-gene product (ras-protein) have previously been established to be key molecules in the intracellular signalling pathway in sponges; increased level ofras-protein mediates events following sponge cell-cell contact. Three unpolluted and three polluted sites in the off-shore seawater around Rovinj (Yugoslavia) were selected for the study in 1989. …
Responses to salt stress in the halophyte Plantago crassifolia (Plantaginaceae)
2004
Abstract General responses to salt stress have been investigated in the halophyte Plantago crassifolia. Seed germination was strongly inhibited by NaCl, although seed viability and germination capacity were not affected by salt pre-treatments. A concentration-dependent inhibition of plant growth was observed in the presence of NaCl, which was accompanied by the accumulation of Na+ ions in the leaves, as determined by cation exchange HPLC. A 20-fold increase of proline content in leaves was observed when plants were treated with 500 m m NaCl, suggesting a protective role against high salinity stress for this amino acid, whose possible mechanism of action is discussed.
Regulatory features of glycogen phosphorylase from frog brain (Rana temporaria)
1985
1. Glycogen content and the activity of glycogen phosphorylase (GPase) are much higher in brain tissue of the Common frog (Rana temporaria) than in brain tissue of mammals and birds (Table 1). 2. In phosphate buffer GPase is extracted from frog orain in a form completely active without addition of AMP and has therefore to be regarded as phosphorylase a. Several procedures to extract the b-form of the enzyme from the tissue have been unsuccessful. In resting skeletal muscle predominantly the AMP dependent b-form is present (Table 1). 3. In vitro, however, the existence of the complete interconverting system can be demonstrated. If NaF (a phosphatase inhibitor) was omitted from the homogeniza…
Studies on the Fibrous Components of the Test ofCiona intestinalisLinnaeus. I. Cellulose-like Polysaccharide
1977
Chemical, histochemical and electron microscopic studies on the fibrous polysaccharide component of the test of Ciona intestinalis L. were made. The results showed cellulose-like fibres to be present in the cuticle layer and in the ground substance. Bundles of fibres varying in diameter from 80 to 600 nm interweave to form a conspicuous network. The bundle appears to be formed of flat fibres, 10–13 nm in width, while the fibre is composed of fibrils 3.5–5 nm; the rectangular cross section of fibres can be supposed. The probable role of this polysaccharide is discussed.
Biogeochemical evaluation of historical sediment contamination in the Gulf of Palermo (NW Sicily): Analysis of pseudotrace elements and stable isotop…
2012
Abstract Sedimentary biogeochemical data from the Gulf of Palermo, which borders one of the major urban and industrial areas of the central Mediterranean, provide a decennial–centennial-scale record of the effects of human activity on this coastal environment. In this study we report trace elements (TE), C org /N tot ratios, δ 13 C org , and δ 15 N tot from dated ( 210 Pb) sediments collected in two coastal stations variably influenced by urban/fluvial loadings and illegal dumping and we compare them with published data for offshore sediments, in order to investigate at a large spatial scale the influence of on-land activities on sedimentary marine system. TE were generally low except for H…
Biological activity of resveratrol, a stilbenic compound from grapevines, against Botrytis cinerea, the causal agent for gray mold
1997
The biological activity of resveratrol, a stilbenic compound synthesized by grapevines in response to various stresses, was reevaluated against Botrytis cinerea using a novel in vitro system that enabled direct observation of the fungus with an inverted microscope. We determined that 90 μg resveratrol/ml reduced germination of B. cinerea conidia by ca. 50%. Moreover, resveratrol was shown to significantly reduce mycelial growth of B. cinerea at concentrations ranging from 60 to 140 μg/ml. Exposure to resveratrol at concentrations ranging from 60 to 140 μg/ml resulted in cytological changes in B. cinerea, such as production of secondary or tertiary germ tubes by conidia, cytoplasmic granulat…
Meiofauna and benthic microbial biomass in a semi-enclosed mediterranean marine system (Stagnone di Marsala, Italy)
2004
Microbial and meiofaunal dynamics and their relationships with the biochemical composition of the sedimentary organic matter were investigated in a semi-enclosed marine system (Marsala lagoon, Western Sicily, Mediterranean Sea). Sediment samples were collected on a monthly basis from March 1996 to February 1997 in four stations located along a N–S transect characterized by different hydrodynamic regimes. Total sedimentary organic matter concentration ranged from 5.681.11 to 156.2812.63 mg g1, while the biopolymeric fraction of organic carbon (BPC, measured as sum of the lipids, carbohydrates and proteins) accounted for only a small fraction (24%) of total organic matter. Total meiofaunal de…
Holothuria tubulosa Gmelin 1791 (Holothuroidea, Echinodermata) enhances organic matter recycling in Posidonia oceanica meadows
2014
Abstract The role of Holothuria tubulosa in organic matter recycling of Posidonia oceanica detritus was estimated in a laboratory feeding experiment. The individual mean ingestion rate of seagrass detritus by holothurians was evaluated and carbon and nitrogen stable isotopes, carbon and nitrogen content and C:N ratio analyzed in H. tubulosa , P. oceanica detritus and surface sediment. Results showed that H. tubulosa is capable of ingesting from 30% to 100% of the detritus produced by P. oceanica meadows, depending on the holothurian density. Stable isotope analysis provided evidence for the assimilation of seagrass detritus by H. tubulosa as their signatures were compatible with 1 trophic l…
Sur la présence de matières organiques mésocénozoïques dans des humus actuels (bassin de Chaillexon, Doubs, France)
1998
Abstract The optical analysis in the Chaillexon watershed (Doubs, France), of the present soils' humus layers' organic matter points out the contribution of Meso-Cenozoic organic matter in addition to the one produced by vegetal cover. Their relative occurrence varies in each layer: in the reverse of that of vegetal organic matter, the relative amount of Meso-Cenozoic organic matter increases according to the depth. That result shows that the total organic matter amounts in soils (and its evaluation) do not only depend on the net primary production and that geological formations have to be taken into account. Moreover, it suggests that present and past detrital supplies are concerned with ‘…
Lactobacillus vini sp. nov., a wine lactic acid bacterium homofermentative for pentoses.
2006
Six strains with more than 99·5 % 16S rRNA gene sequence similarity, identical internal spacer region profiles and restriction analysis of the amplified 16S rRNA gene patterns were isolated from fermenting grape musts during independent studies carried out in France and Spain many years apart. Strains are Gram-positive, motile, facultatively anaerobic rods that do not exhibit catalase activity and have the ability to utilize pentose sugars (ribose and/or l-arabinose), although they are homofermentative bacteria. Strains ferment pentoses exclusively yielding lactic acid as the end product. A broad set of molecular techniques has been applied to characterize these strains and the results show…