Search results for "botany"

Carotenoid-based colour polyphenism in a moth species: search for fitness correlates

2007

Carotenoid-based integumental coloration is often associated with individual performance in various animals. This is because the limited amount of the pigment has to be allocated to different vital functions. However, most of the evidence for the carotenoid-based trade-off comes from vertebrate studies, and it is unclear if this principle can be applied to insects. This possibility was investigated in Orgyia antiqua L. (Lepidoptera: Lymantriidae). The larvae of this species are polyphenic in their coloration, varying from a highly conspicuous combination of yellow hair tufts on black background to cryptic appearance with brown hair tufts. The conspicuous larvae are aposematic, advertising t…

Effects of UVB radiation exposure from the molecular to the organism level in macrophytes from shallow Mediterranean habitats

2015

Abstract The available data on the effects of UVB radiation (UVBR) are scarce for submerged macrophytes, particularly charophytes. We studied the effects of UVBR on Chara baltica, Chara hispida, Chara vulgaris, Nitella hyalina and Myriophyllum spicatum, collected from shallow Mediterranean waterbodies. In a short-term laboratory experiment, we subjected these species to three different UVBR treatments corresponding to daily biologically effective integrated doses of 0, 1 and 6 kJ m−2. The analysed response variables were DNA damage, UV-absorbing compounds (both the methanol-soluble–SUVACs- and, for the first time in charophytes, the methanol-insoluble cell wall-bound fraction–WUVACs-), the …

Hormone Effects on the Membrane Potential and on Sucrose-Induced Depolarization of Young <italic>Citrus</italic> Leaves

1992

Design of the Biotechnological System for the Cultivation of a Polysaccharide-Producing Microorganism and Metabolites Separation

1970

This paper presents a design of the biotechnological system established for the cultivation of a polysaccharide-producing microorganism and the separation of the polysaccharide together with other metabolites. The strain used is a halophilic archaeon called Haloferax mediterranei (Mironescu et al., 2003). On designing the biotechnological system, some requirements are important: The recipients and the pipes must be resistant to the corrosion action of the cultivation substrate very rich in NaCl (125 to 150 g/l); A command and control system for pH, temperature and substrate and inoculum feeding is necessary; A system for monitoring dissolved oxygen and gases evacuated from the bioreactor (O…

Acid Carboxypeptidases in Grains and Leaves of Wheat, Triticum aestivum L

1986

Extracts of resting and germinating (3 days at 20 degrees C) wheat (Triticum aestivum L. cv Ruso) grains rapidly hydrolyzed various benzyloxycarbonyldipeptides (Z-dipeptides) at pH 4 to 6. Similar activities were present in extracts of mature flag leaves. Fractionation by chromatography on CM-cellulose and on Sephadex G-200 showed that the activities in germinating grains were due to five acid carboxypeptidases with different and complementary substrate specificities. The wheat enzymes appeared to correspond to the five acid carboxypeptidases present in germinating barley (L Mikola 1983 Biochim Biophys Acta 747: 241-252). The enzymes were designated wheat carboxypeptidases I to V and their …

Comparison of the Biosynthesis of Cellulose in vitro and in vivo in Cotton Bolls

1966

THE work of Hassid et al.1–3 on the cell-free synthesis of cellulose with an enzyme system isolated from mung bean seedlings and young cotton bolls has shown that the enzyme is apparently unable to distinguish guanosine diphosphate-D-glucose from guanosine diphosphate-D-mannose. Moreover, there was a notable decrease in the amount of the synthesized cellulose using enzymes from cotton bolls older than 15 days.

Fatty acid composition of mutants of the moss Physcomitrella patens

1981

Abstract The fatty acid composition of various mutant strains of the moss Physcomitrella patens has been compared to the wild-type. These included strains defective in their responses to auxins and/or cytokinins, one which releases much more cytokinin into the medium than the wild-type, and two aphototropic strains. The lipids of the aphototropic mutants were also studied after culture in different light regimes. Although some differences in fatty acid composition have been found between strains, these alone are probably not responsible for their physiological differences. Considerable changes occur in many fatty acids in senescent or dark-grown material, including changes in the proportion…

Secondary somatic embryogenesis and plant regeneration in myrtle (Myrtus communis L.).

1998

Immature seeds, as well as hypocotyls and cotyledons excised from seedlings of Myrtus communis L., were cultured on media containing half-strength Murashige and Skoog macronutrients (MS/2) with combinations of auxins and cytokinins, in order to study their morphogenetic competence. Somatic embryogenesis was obtained from cotyledons, hypocotyls and 2-month-old immature seeds with 0.1 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). The percentage of explants showing this primary somatic embryogenesis ranged from 4% for hypocotyls to 12% for 2-month-old immature seeds. In the latter, somatic embryogenesis was also obtained in media containing 2,4-D plus a cytokinin, and with only a cytokinin. Som…

Total lipids content and fatty acid composition of seed oils from six pomegranate cultivars

1995

The fatty acid composition of the seed oils of six pomegranate (Punica granatum L) cultivars was qualitatively and quantitatively determined by gas chromatography. The seeds contained oil in the range 51-152 mg kg -1 dry matter. Intervarietal differences in fatty acid composition were demonstrated (fatty acid esters as % (w/w) total fatty acid esters. Sour varieties had the highest while sour-sweet varieties had the lowest oil content. Eleven fatty acids were identified. In all varieties, the predominant fatty acids were linoleic (25.2-38.6%) and oleic acid (24.8-35.5%) followed by palmitic (18.2-22.6%), stearic (6.9-10.4%) and linolenic acid (0.6-9.9%). To a lesser extent arachidic (1.1-3.…

Characterization of 1-aminocyclopropane-1-carboxylic acid oxidase from barley (Hordeum vulgare L.) seedlings and pine (Pinus sylvestris L.) needles

1999

Abstract Biochemical characteristics of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase extracted from barley ( Hordeum vulgare L.) leaves and pine ( Pinus sylvestris L.) needles were investigated. ACC oxidase from barley leaves was soluble while for complete recovery of ACC oxidase from pine needles addition of Triton X-100 to extraction medium was necessary. The enzyme required Fe 2+ , ascorbate and NaHCO 3 for maximum activity. A non-linear time course of ACC oxidase reaction indicated possible catalytic inactivation of the enzyme. The maximum activity was measured at pH 7.0–7.2 for ACC oxidase from both barley leaves and pine needles. The apparent K m for ACC was found to be 77 and …