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91.
S. N. Fajardo S. Valenzuela A. F. Dos Santos M. P. González E. A. Sanfuentes 《Forest Pathology》2017,47(6)
Mortality of Nothofagus trees in the southern‐central Chile region has been observed for over 30 years. A field survey conducted in 2013 detected partial defoliation and bleeding cankers on Nothofagus obliqua in a pure stand in the Nahuelbuta coastal ranges of the Biobío region. A Phytophthora sp. was isolated from stem cankers and soil samples around symptomatic N. obliqua trees: All isolates were identified as Phytophthora pseudosyringae. These isolates were pathogenic on 1‐year‐old N. obliqua and Nothofagus alpina, and on detached twigs of adult N. obliqua and Nothofagus dombeyi trees. This paper is the first to report association and pathogenicity of P. pseudosyringae with N. obliqua, N. alpina and N. dombeyi native to the Biobío region of Chile. The potential of P. pseudosyringae to cause damage in natural Nothofagus stands in Chile must be determined. 相似文献
92.
Erika López-Soto;Gillian Ord;Manuel I. Castillo;Guido Plaza;Mario A. Cáceres;María Teresa González;Maritza Sepúlveda;Alicia I. Guerrero;Andrea Piñones;Mauricio F. Landaeta; 《Fisheries Oceanography》2024,33(6):e12690
Early life history traits of small pelagic fish are usually affected by environmental conditions. Patagonian sprat, Sprattus fuegensis, is a small pelagic fish that inhabits the continental shelf, fjords and channels of Patagonia. Their larvae are usually exposed to large variations in physical and biological conditions. We evaluated the effects of environmental conditions on early life history traits of this key species encompassing over 20 years of information. The characterization of oceanographic features, larval abundance and distribution was carried out in western Patagonia between 1996 and 2019, while the growth and mortality rates were estimated for the austral spring 2019 between 49°54′S and 53°55′S. Larval abundance decreased three to ten times from 1996 to 1997 to the rest of the study period (2008–2010 and 2014–2019), with larger abundances being found over the shelf. In spring 2019, the growth rate was 0.20 ± 0.05 mm d−1 for larvae between 9 and 19 days after hatching. The growth rate was similar in partially stratified (7–50 J m−3) and stratified waters (50–100 J m−3), but slower in mixed waters (< 7 J m−3). GAM modelling showed that the faster larval growth occurred in partially stratified waters with temperatures above 7.5°C. Natural mortality rates were higher in partially stratified waters (24% of daily loss), lower in stratified areas (14%) and the lowest in the mixed water column (12%). Accordingly, larvae living in channels had faster growth rates but higher daily mortality, while those that hatched or were advected to water parcels on the continental shelf had slower growth but lower daily mortality. Finally, these latter traits may be an example of an inverse growth-selective survival strategy. 相似文献
93.
Chemical composition and antifungal activity of essential oil of Chrysactinia mexicana gray 总被引：1，自引：0，他引：1
Cárdenas-Ortega NC Zavala-Sánchez MA Aguirre-Rivera JR Pérez-González C Pérez-Gutiérrez S 《Journal of agricultural and food chemistry》2005,53(11):4347-4349
The chemical composition of the essential oil of Chysactinia mexicana was analyzed by gas chromatography-mass spectrometry. Seventeen compounds were characterized; eucalyptol (41.3%), piperitone (37.7%), and linalyl acetate (9.1%) were found as the major components. The essential oil of leaves and piperitone completely inhibited Aspergillus flavus growth at relatively low concentrations (1.25 and 0.6 mg/mL, respectively). 相似文献
94.
Sánchez Ramos O González Pose A Gómez-Puerta S Noda Gomez J Vega Redondo A Águila Benites JC Suárez Amarán L Parra NC Toledo Alonso JR 《Comparative immunology, microbiology and infectious diseases》2011,34(3):259-265
Recombinant adenoviral vectors have emerged as an attractive system for veterinary vaccines development. However, for poultry vaccination a very important criterion for an ideal vaccine is its low cost. The objective of this study was to test the ability of chicken CD154 to enhance the immunogenicity of an adenoviral vector-based vaccine against avian influenza virus in order to reduce the amount of antigen required to induce an effective immune response in avian. Chickens were vaccinated with three different doses of adenoviral vectors encoding either HA (AdHA), or HA fused to extracellular domain chicken's CD154 (AdHACD). Hemagglutination inhibition (HI) assay and relative quantification of IFN-γ showed that the adenoviral vector encoding for the chimeric antigen is able to elicit an improved humoral and cellular immune response, which demonstrated that CD154 can be used as a molecular adjuvant allowing to reduce in about 50-fold the amount of adenoviral vector vaccine required to induce an effective immune response. 相似文献
95.
New Forests - Mediterranean holm oak forests are subjected to chronic seasonal droughts coinciding with the warmest conditions during the summer. Importantly, climate change projections support... 相似文献
96.
Rough vaccines in animal brucellosis: structural and genetic basis and present status 总被引：14，自引：0，他引：14
Moriyón I Grilló MJ Monreal D González D Marín C López-Goñi I Mainar-Jaime RC Moreno E Blasco JM 《Veterinary research》2004,35(1):1-38
Brucellosis control and eradication requires serological tests and vaccines. Effective classical vaccines (S19 in cattle and Rev 1 in small ruminants), however, induce antibodies to the O-polysaccharide of the lipopolysaccharide which may be difficult to distinguish from those resulting from infection and may thus complicate diagnosis. Rough attenuated mutants lack the O-polysaccharide and would solve this problem if eliciting protective immunity; the empirically obtained rough mutants 45/20 and RB51 have been used as vaccines. Strain 45/20 is reportedly unstable and it is not presently used. RB51 is increasingly used instead of S19 in some countries but it is rifampicin resistant and its effectiveness is controversial. Some controlled experiments have found good or absolute protection in adult cattle vaccinated orally (full dose) or subcutaneously (reduced dose) and in one field experiment, RB51 was reported to afford absolute protection to calves and to perform better than S19. Controlled experiments in calves, however, have shown reduced doses of RB51 to be ineffective, full doses only partially effective, and RB51 less effective than S19 against severe challenges. Moreover, other observations suggest that RB51 is ineffective when prevalence is high. RB51 is not useful in sheep and evidence in goats is preliminary and contradictory. Rough mutants obtained by molecular biology methods on the knowledge of the genetics and structure of Brucella lipopolysaccharide may offer alternatives. The B. abortus manBcore (rfbK) mutant seems promising in cattle, and analyses in mice suggest that mutations affecting only the O-polysaccharide result in better vaccines than those affecting both core and O-polysaccharide. Possible uses of rough vaccines also include boosting immunity by revaccination but solid evidence on its effectiveness, safety and practicality is not available. 相似文献
97.
A. Bautista-Cruz R. Carrillo-Gonzlez M.R. Arnaud-Vias C. Robles F. de Len-Gonzlez 《Soil & Tillage Research》2007,96(1-2):342-349
This study examined the variations in soil physical, chemical and biological properties from Agave angustifolia fields in three sites with different topographic conditions (valley, hill and mountain), in Oaxaca, Mexico, associated with the tillage systems, disk ploughing (DP), animal drawn ploughing (ADP) and minimum tillage (MT), respectively. Plant ages were 1.5–3.5 years (class 1), 3.6–5.5 years (class 2) and 5.6–7.5 years (class 3). Soil samples were taken at two soil depths (0–20 and 21–40 cm) from plots of 4000 m2 within each site and plant age classes, during the spring of 2005. The main changes in soil properties were found in the mountain site. Soil bulk density (2.0 g cm−3), cone penetration resistance (CPR) (3.96 MPa), 0.7 and 1.0 mm water stable aggregates (WSA) (28.3 g kg−1 and 102.2 g kg−1, respectively) were higher in the mountain site than in the hill and valley fields. This result is consistent with the rocky substrate beneath the shallow soil. Soil organic carbon (SOC) (23.9 g kg−1), available N (23.1 mg kg−1) and soil microbial biomass carbon (SMBC) (969.6 μg g−1) at the mountain site showed the highest values, suggesting that MT practiced in this topographic condition favours the organic matter accumulation and biological activity. Soil microbial biomass carbon and SOC seem to be the soil properties that were mainly affected by the sites and soil management associated with them. For the three sites, SOC, POlsen, available N, exchangeable Na+ and SMBC were higher at 0–20 cm depth than at 21–40 cm depth within each site. Exchangeable Ca2+ and K+, POlsen and CPR increased with plant age. In contrast, available N decreased. Soil chemical properties were more affected by the age of the plant than physical and biological properties. Results reported here represent a reference of the fertility properties of soils cultivated with A. angustifolia, which could be used in further studies focused on management and tillage systems. 相似文献
98.
Daniel Moreno-Fernández Isabel Cañellas Rafael Calama Javier Gordo Mariola Sánchez-González 《Annals of Forest Science》2013,70(8):761-768
Context
Edible stone pine (Pinus pinea L.) nut is a forest product which provides the highest incomes to the owners of stone pine forests.Aim
The objective of this work is to evaluate the effect of first thinning on growth and cone production in an artificially regenerated stand in order to determine optimum intensity.Methods
A thinning trial was installed in 2004 to compare two thinning regimes (heavy and moderate) and a control treatment. From 2004 to 2012, six inventories of forest attributes were carried out, and the cone crop was harvested annually. We evaluated the effect of thinnings on growth using repeated measures analysis of variance with a mixed model approach. With regards to cone production, we first estimated the probability of finding cones in a tree by applying a generalized mixed model and then estimated cone production by using a mixed model, including climatic variables.Results
We found that thinning had a positive influence on tree diameter increment. Thinning increased the probability of finding cones and cone production. However, significant differences between heavy and moderate thinnings were not found.Conclusion
We recommend early silvicultural treatments in stone pine stands to favor the development of trees and larger edible pine nut production. 相似文献99.
Fei Yang Graham P Head Paula A Price Jos C Santiago Gonzlez David L Kerns 《Pest management science》2020,76(11):3676-3684
100.
The experimental trials on dead animal composting have been carried out on a poultry farm, using cereal straw and solid hen manure. Other farm wastes such as cardboard and nonmarketable eggs were also included in the last three trials. Eight trials have been conducted on a real-life scale, in the open air and at different times of year using a simple pile system. The pile was moistened with water or with liquid hen manure from a nearby manure lagoon, as necessary. The ratios straw/hen manure and (straw + hen manure)/dead poultry used in the different piles ranged between 4/1 and 5/1 for the first one and 8/1 and 2/1 for the second one. In all trials two clearly different stages were observed. A primary stage where high temperatures (53-66 °C) within the curing pile were reached and the poultry mortalities were completely degraded while straw was only partially degraded. No turnings were made in this stage. The secondary stage used a standard dynamic pile system with turnings and watering. A device was fitted in order to collect ammonia emission and it was observed that this emission is higher when both moisture and the ratio (straw + hen manure)/poultry mortalities are lower and when temperatures are higher. The end by-product has an excellent appearance and can be marketed as organic fertilizer or organo-mineral (C:N between 7.94 and 14.09). 相似文献