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11.
Nevain A. S. Messiha Ariena H. C. van Bruggen Anne D. van Diepeningen Oscar J. de Vos Aad J. Termorshuizen N. N. A. Tjou-Tam-Sin J. D. Janse 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(4):367-381
Ralstonia solanacearum race 3 biovar 2, the causative agent of potato brown rot (bacterial wilt), is an economically important disease in tropical,
subtropical and temperate regions of the world. In view of previous reports on suppression of the disease by organic amendments,
and the expansion of organic agriculture, it was timely to compare the effects of organic and conventional management and
various amendments on brown rot development in different soils (type: sand or clay; origin: Egypt or the Netherlands). Brown
rot infection was only slightly reduced in organically compared to conventionally managed sandy soils from Egypt, but organic
management significantly increased disease incidence and pathogen survival in Dutch sandy and clay soils, which correlated
with high DOC contents in the organic Dutch soils. There was no correlation between disease incidence or severity and bacterial
diversity in the potato rhizosphere in differently managed soils (as determined by 16S DGGE). NPK fertilization reduced bacterial
wilt in conventional Egyptian soils but not in Dutch soils. Cow manure amendment significantly reduced disease incidence in
organic Dutch sandy soils, but did not affect the bacterial population. However, cow manure did reduce densities of R. solanacearum in Egyptian sandy soils, most probably by microbial competition as a clear shift in populations was detected with DGGE in
these and Dutch sandy soils after manure amendment. Amendment with compost did not have a suppressive effect in any soil type.
The absence of a disease suppressive effect of mineral and organic fertilization in Dutch clay soils may be related to the
already high availability of inorganic and organic nutrients in these soils. This study shows that the mechanism of disease
suppression of soil-borne plant pathogens may vary strongly according to the soil type, especially if quite different types
of soil are used. 相似文献
12.
We established protocols for the analysis of genetic diversity in chayote (Sechium edule) by using isozyme markers, thereby determining the level of genetic diversity present in 42 accessions of chayote from Costa
Rica. We obtained clear and reproducible zymograms for eight enzyme staining systems: PGM, 6-PGD, PGI, IDH, MDH, SOD, SKD,
and EST, and were able to score 14 putative loci. Eight of the 14 loci examined were polymorphic. We found 35 distinct multilocus
genotypes among these accessions. Five of these multilocus genotypes were homozygous for all loci. In addition, our data also
revealed that most of the multilocus genotypes (24) were heterozygous for only one of the eight loci, and the rest were heterozygous
for two or three loci (9 and 4 accessions, respectively). Seven multilocus genotypes were found in two different accessions.
Dice similarity coefficient was used to study the relationship between accessions. This analysis, based on the presence and
absence of alleles, revealed that accessions collected in the same location seldom shared the same multilocus genotype. The
value of isozyme polymorphisms as tools to continue studies on the characterization of chayote is discussed. 相似文献
13.
Frederic Vandeperre Ruth M. Higgins Julio Sánchez‐Meca Francesc Maynou Raquel Goñi Pablo Martín‐Sosa Angel Pérez‐Ruzafa Pedro Afonso Iacopo Bertocci Romain Crec’hriou Giovanni D’Anna Mark Dimech Carmelo Dorta Oscar Esparza Jesús M. Falcón Aitor Forcada Ivan Guala Laurence Le Direach Concepción Marcos Celia Ojeda‐Martínez Carlo Pipitone Patrick J. Schembri Vanessa Stelzenmüller Ben Stobart Ricardo S. Santos 《Fish and Fisheries》2011,12(4):412-426
Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta‐analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no‐take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no‐take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no‐take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no‐take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs. 相似文献
14.
Mike Sun Susan Siemsen William Campbell Pablo Guzman Robert Davidson Jonathan L. Whitworth Terry Bourgoin Jeff Axford Willem Schrage Gary Leever Alan Westra Steve Marquardt Hossien El-Nashaar Jeff McMorran Oscar Gutbrod Tom Wessels Robert Coltman 《American Journal of Potato Research》2004,81(3):227-231
Fourteen United States (U.S.) seed potato certification agencies surveyed all U.S. seed potato growing areas for presence of the potato spindle tuber viroid (PSTVd). The survey included general surveillance, which involved searching for the occurrence of PSTVd in state seed potato certification records from 1990 through 2000, and a field survey, which involved testing selected crops for PSTVd infection by nucleic acid dot blot hybridization during 1999 through 2001. No PSTVd incident was documented in any of the state certification records, nor was PSTVd detected in the field surveys. All U.S. seed-growing areas were determined to be free of PSTVd. It is concluded that PSTVd has been eradicated and freedom from potato spindle tuber viroid has been successfully maintained in all of the seed potato growing areas in the United States. 相似文献
15.
Peters SM Yancy H Deaver C Jones YL Kenyon E Chiesa OA Esparza J Screven R Lancaster V Stubbs JT Yang M Wiesenfeld PL Myers MJ 《Veterinary immunology and immunopathology》2012,148(3-4):236-242
Non-steroidal anti-inflammatory drugs (NSAID) are a family of chemicals that function to reduce pain, fever, and inflammation, and they are commonly used in people and animals for this purpose. Currently there are no NSAIDs approved for the management of inflammation in swine due to a lack of validated animal models and suitable biomarkers to assess efficacy. A previous in vitro study examining biomarkers of inflammation identified fourteen genes that were significantly altered in response to Escherichia coli lipopolysaccharide (LPS)-induced inflammation. In the present study, five of those fourteen genes were tested in vivo to determine if the same effects observed in vitro were also observed in vivo. Plasma levels of prostaglandin E(2) (PGE(2)), an essential mediator of fever and inflammation, were also determined. Two groups of swine were stimulated with LPS with the second group also treated with flunixin meglumine. Blood was collected at 0, 1, 3, 6, 8, 24, and 48h post LPS-stimulation. The RNA was extracted from the blood and quantitative real-time-PCR (qRT-PCR) was utilized to determine the expression patterns of CD1, CD4, serum amyloid A2 (SAA2), Caspase 1, and monocyte chemoattractant protein 1 (MCP-1). The LPS-stimulated animals demonstrated a statistically significant alteration in expression of SAA2 and CD1 at 3h post-stimulation. Flunixin meglumine treated animals' demonstrated reduced expression of CD1 in comparison to the LPS-stimulated swine at 24 and 48h post LPS-stimulation. Flunixin meglumine treated animals exhibited reduced expression of SAA2 at 48h post-stimulation compared to LPS-stimulated swine. Swine treated with LPS demonstrated statistically significant increases in plasma PGE(2) at 1h post-stimulation. Swine treated with flunixin meglumine had no increase in plasma PGE(2) levels at any time. These results demonstrate that PGE(2) production, along with two out of five genes (SAA2 and CD1) have the potential to serve as early biomarkers of inflammation as well as indicators of NSAID efficacy. 相似文献
16.
Ardanuy Agns Figueras Mart Matas Montserrat Arn Judit Agust Nuria Alomar scar Albajes Ramon Gabarra Rosa 《Journal of pest science》2022,95(1):447-459
Journal of Pest Science - Conservation biological control involves manipulation of the environment to enhance the effectiveness of natural enemies in controlling crop pests. In this study, we... 相似文献
17.
Oscar Goñi María T. Sanchez-Ballesta Carmen Merodio María I. Escribano 《Postharvest Biology and Technology》2010,55(3):169-173
In order to obtain a better understanding of the active defense strategy of cherimoya (Annona cherimola Mill.) fruit, hydrolytic and antifungal activity, as well as expression of proteins functionally and immunogenically related to the pathogenesis-related proteins chitinase (PR-Q) and 1,3-β-glucanase (PR-2), were estimated in fruit at different ripening stages. Increase in expression of the 27 kDa constitutive chitinase and the induction of two new proteins, a 26 kDa chitinase and a 51 kDa 1,3-β-glucanase were associated with enhanced in vitro hydrolytic and antifungal activity of the acidic protein extract in ripe fruit. Ripening modified the expression of constitutive basic isoenzymes, with a sharp decrease in both relative accumulation and hydrolytic activity. Likewise, a new basic 33 kDa chitinase was induced in the over-ripe fruit, concomitant with accumulation of a basic constitutive 76 kDa 1,3-β-glucanase. At this stage, the basic protein extract modified in vitro growth inhibition of Botrytis cinerea. Short-term high CO2 treatment delayed fruit ripening and maintained a similar distribution of activity and isoenzymatic pattern in both protein fractions to that in unripe fruit. These results indicate that the changes in the pattern of defense proteins and hydrolytic activity in cherimoyas appear to be associated with ripening. Moreover, unlike the constitutively expressed isoenzymes, only the transitorily induced chitinases and 1,3-β-glucanases were associated with an active defense-related response. 相似文献
18.
19.
A biologically-consistent stand growth model for loblolly pine in the Piedmont physiographic region, USA 总被引:1,自引:0,他引:1
Oscar García Harold E. BurkhartRalph L. Amateis 《Forest Ecology and Management》2011,262(11):2035-2041
A theory-influenced dynamical stand growth model formulation described well the behavior of thinned and unthinned loblolly pine plantations. A simplification containing few free parameters performed as well as a fully parametrized version. It seems particularly well suited to situations where available data is scarce. The stand model can be interfaced to additional climate, nutrition and carbon cycling modules for studying the effects of a changing environment. 相似文献
20.