CAPTURA. Repositorio Academico de la Universidad de Chile
(5.176 recursos)
Captura almacena y conserva la producción de conocimiento generado por docentes e investigadores de la Universidad de Chile, y la hace visible desde los portales académicos internacionales.
Mostrando recursos 1 - 20 de 38
1.
Biodiversity of uptake hydrogenase systems from legume endosymbiotic bacteria - Brito, B.; Baginsky, Cecilia; Palacios, J. M.; Cabrera, E.; Ruiz-Argüeso, T.; Imperial, J.
Uptake hydrogenases in legume endosymbiotic bacteria recycle hydrogen produced during the nitrogen fixation process in legume nodules. Despite the described beneficial effect on plant productivity, the hydrogen oxidation capability is not widespread in the Rhizobiaceae family. Characterization of hydrogenase gene clusters in strains belonging to Rhizobium, Bradyrhizorbium and Azorhizobium reveals a similar overall genetic organization along with important differences in gene regulation. in addition, phylogenetic analysis of hup genes indicates distinct evolutionary origins for hydrogenase genes in Rhizobia.
2.
Acaricidal action of two detergents against Panonychus ulmi (Koch) and Panorlychus citri (Mcgregor) (Acarina : Tetranychidae) in the laboratory - Curkovic, Tomislav; Araya Cléricus, Jaime Eduardo
Two laboratory experiments using a leaf-dip technique evaluated the effect of two detergents, Quix and Nobla, on Panonychus ulmi and P. citri. Fenazaquin 0.01% a.i. was used on P. ulmi as a standard. Mortality increased with higher concentrations in both mite species. In addition, detergent treatments also dislodged P. citri mites from leaves. Dislodged + dead mites varied between 31.7% (Quix 0.25%) and 91.3% (Nobla 0.45%), in comparison with 22% in the control. These results suggest the need to evaluate the use of detergents against both mite species in field orchards.
3.
Biocontrol of root and crown rot in tomatoes under greenhouse conditions using Trichoderma harzianum and Paenibacillus lentimorbus. Additional effect of solarization - Montealegre, Jaime; Herrera, Rodrigo; Velásquez, Juan Carlos; Silva, Poliana; Besoaín, Ximena; Pérez, Luz María
richoderma harzianum 650 (Th650) and Paenebacillus lentimorbus 629 (P1629) selected earlier for their ability to control Rhizoctonia solani, Fusarium solani and F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide (MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex F. oxysporum f. sp. lycopersici-Pyrenochaeta lycopersici-Rhizoctonia solani. Evaluations were also performed independently for root damage caused by P. lycopersici, and also for R. solani in the summer assay. MeBr decreased tomato root damage caused by the complex from...
4.
Identification of a dominant SCAR marker associated with colour traits in Coho salmon (Oncorhynchus kisutch) - Araneda, Cristian; Neira, Roberto; Iturra, Patricia
Flesh colour in salmonids is a very important commercial trait that shows additive genetic variance with significant environmental influence. Selective breeding for this trait is difficult, since phenotypic evaluation requires individuals to be sacrificed for scoring. We have identified a RAPD marker that co-segregates with colour traits scored as breeding values based on visual evaluations of flesh colour in Coho salmon. The experimental approach included RAPD screening with 440 primers and selective DNA pooling. Individuals used to make pools were selected according to their high and low breeding values as predicted using a DFREML algorithm. A single RAPD polymorphism segregating...
5.
Residual and sub-lethal effects of an attracticide formulation on Choristoneura rosaceana (Harris), Pandemis pyrusana Kearfott, and Cydia pomonella (L.) males (Lepidoptera : Tortricidae) - Curkovic, Tomislav; Brunner, Jay F.
A bioassay was developed to evaluate effects on Choristoneura rosaceana (Harris), Pandemis pyrusana Kearfott, and Cydia pomonella (L.), males exposed to an attracticide loaded with 6% permethrin and aged under field conditions. High levels of knock down (> 97%) at 1 h, and mortality (> 94%) at, 24 h after exposure to fresh attracticide were observed among the three species. Mortality and knock down decreased linearly as the attracticide aged and was greater than 50% even with attracticide aged 30 days. Leg autotomy was observed in all three species, being a novel response for both leafroller species. Leg autotomy reached...
6.
Fibre concentrates from apple pomace and citrus peel as potential fibre sources for food enrichment - Figuerola, Fernando; Hurtado, María de la Luz; Estévez, Ana María; Chiffelle, Ítalo; Asenjo, Fernando
Research to evaluate some functional properties of fibre concentrates from apple and citrus fruit residues, in order to use them as potential fibre sources in the enrichment of foods, was carried out. Fiber concentrates were analysed for their proximate content (moisture, lipids, protein and ash); caloric value; dietary fibre composition and functional properties (water retention capacity WRC, swelling capacity - SW, fat adsorption capacity - FAC and texture). All the fibre concentrates had a high content of dietary fibre (between 44.2 and 89.2 g/100 g DM), with a high proportion of IDF. Protein and lipid contents ranged between 3.12 and...
17.
Short communication. Toxicity of abamectin, acetamiprid, imidacloprid, mineral oil and an industrial detergent with respect to Encarsia formosa (Gahan) parasitizing Trialeurodes vaporariorum Westwood nymphs - Araya, J. E.; Estay, P.; Araya, M. H.
The control of Trialeurodes vaporariorum on tomato with Encarsia formosa is influenced by the use of insecticides. Nine days after allowing E. formosa adults to lay their eggs in T vaporariorum nymphs on tomato plants, insecticide solutions (abamectin, mineral oil, acetamiprid, an industrial detergent and imadacloprid) were applied at the highest recommended dosages to tomato leaflets in Petri dishes using a Potter tower (four replicates, each involving 20 parasitized nymphs). Adult parasitoids began to emerge on day 7 post-application; this lasted 3-4 days, peaking on day 9 post-application. All the tested products killed the E. formosa pupae (an effect significantly...
18.
Genetic diversity of wild species and cultivated varieties of alstroemeria estimated through morphological descriptors and RAPD markers - Aros, Danilo; Meneses, Claudio; Infante, Rodrigo
In order to estimate the genetic diversity within the Alstroemeriaceae family, nine wild alstroemeria accessions. 10 commercial varieties and the monotype Leontochir ovallei were evaluated using two different methods. RAPD analysis and UPOVs morphological descriptors. DNA from leaves, roots and tepals were analyzed by RAPDs with eight primers that generated 236 RAPD bands, Dendrograms obtained allowed identification of five main clusters: A. garaventae alone, wild alstroemerias, commercial varieties, A. exserens and A. spathulata together. and L. ovallei. Twenty-five morphological descriptors related to stem, leaf and inflorescence characteristics were evaluated and a resulting dendrogram was analyzed containing two main clusters: one...
19.
Differential adaptation of two varieties of common bean to abiotic stress - I. Effects of drought on yield and photosynthesis - Lizana, Carolina; Wentworth, Mark; Martínez, Juan P.; Villegas, Daniel; Meneses, Rodrigo; Murchie, Erik H.; Pastenes, Claudio; Lercari, Bartolomeo; Vernieri, Paulo; Horton, Peter; Pinto, Manuel
The yield of 24 commercial varieties and accessions of common bean (Phaseolus vulgaris) has been determined at different sites in Chile and Bolivia. Statistical analysis was performed in order to characterize whether a particular variety was more or less stable in yield under different environmental conditions. Amongst these, two varieties have been identified for more detailed study: one variety has a higher than average yield under unstressed conditions but is strongly affected by stress, and another has a reduced yield under unstressed conditions but is less affected by stress. The contrasting rate of abscission of the reproductive organs under drought...
20.
Structural determination and chemical modifications of the polysaccharide from seeds of Prosopis chilensis Mol. (Stuntz) - Matsuhiro, Betty; Presle, Luis C.; Saenz, Carmen; Urzúa, Carlos C.
The polysaccharide extracted from Prosopis chilensis seeds in acidic medium showed by total hydrolysis and gas-liquid chromatography analysis of the alditol acetates to be composed of galactose and mannose in the molar ratio 1.0:1.9. Studies by methylation and H-1 and C-13 NMR spectroscopy indicated that the polysaccharide was a galactomannan with a chain of D-mannopyranosyl residues linked beta 1 -> 4 which carried alternatively a-D-galactopyranosyl residues at position O-6 of D-mannose units. The chemical modification of the galactomannan by reaction with sodium chloroacetate afforded in 95.3% yield, a derivative which gave a very viscous solution with water. By titration it...
1.
