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11.
Infection and colonization of melon roots by Monosporascus cannonballus in two cropping seasons in Arizona and California 总被引：1，自引：0，他引：1
M. E. Stanghellini † D. H. Kim M. M. Waugh D. M. Ferrin T. Alcantara S. L. Rasmussen 《Plant pathology》2004,53(1):54-57
Although canopy collapse of melons (one of the above-ground symptoms of vine decline caused by Monosporascus cannonballus ) occurred late in the growing season, the onset of root infection occurred much earlier. In three early winter-spring and two late winter-spring crops, the onset of root infection occurred 47–65 and 35–36 days after planting, respectively. In contrast, in four summer-autumn crops, the onset of root infection occurred within 9–17 days after planting. Vine decline occurred commonly in winter-spring crops, but did not occur in any of the summer-autumn crops. Following the onset of root infection, the percentage of plants infected increased at rates of 0·031–0·036 and 0·038–0·070 per unit per day for winter-spring and summer-autumn crops, respectively, based on the monomolecular disease progress model. Root lesions were first observed 14–42 days after the onset of infection in winter-spring crops, and 14–28 days after the onset of infection in summer-autumn crops. Pathogen reproduction occurred primarily at the end of each growing season. 相似文献
12.
The abalone Haliotis diversicolor (Reeve) or ‘tokobushi’ is being cultured in Kagoshima, southern Japan for stock enhancement of fishing grounds. However, with decreasing catches from the wild some fishermen's group may eventually resort to rearing tokobushi until of marketable size. Growth experiments of tokobushi fed macroalgae in floating net cage and plastic tanks were conducted to evaluate the influence of culture system, macroalgal food, age and water temperature on their culture. In floating net cage, marketable sizes were obtained at the age of 457–822‐day old (15–27‐month old) with highest growth rate of 2.36% g day?1 and 0.21 mm day?1. One advantage of the plastic tank culture system was that the tokobushi shell remained clean throughout the culture period. Macroalgal food affected the growth rate; Sargassum fusiforme (Setchell)‐ and Ulva pertusa (Kjellman)‐fed tokobushi were better than Meristotheca papulosa (Montagne)‐fed. Further, 1‐year‐old tokobushi had better growth performance and condition index than the 2‐year‐old cohort, and growth rates were higher at 17°C than at 12°C. These findings should help tokobushi farmers design their mariculture scheme considering both economic and environmental aspects. 相似文献
13.
Konrad Dabrowski Jacques Rinchard Joseph S. Ottobre Fernando Alcantara Palmira Padilla Andrzej Ciereszko Marcos J. De Jesus Christopher C. Kohler 《Journal of the World Aquaculture Society》2003,34(4):441-449
Broodstock pacu Piaractus brachypomus as well as their eggs during their embryonic development were exposed to either normoxia (5.5–7.5 mg O2 /L) or hypoxia (2.0–4.5 mg O2 /L) conditions. The plasma concentrations of 11-ketotestosterone in males and estradiol-17β in females, as well as that of their precursor testosterone (T) were significantly ( P < 0.01) higher in fish maintained under normoxic conditions than in fish exposed to hypoxia. After ovulation and spermiation induced by hormonal treatments, the plasma concentrations of T and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) significantly ( P 0.05) increased in both sexes under both normoxic and hypoxic conditions. The plasma levels of T and 17,20βP achieved under normoxic conditions were higher than the ones recorded under hypoxia, except for those of 17,20βP in males. Males responded positively to the hormonal treatments, and the concentration of spermatozoa was 10.5 ± 0.8 109 /mL under both oxygen conditions. Hypoxia resulted in significantly lower survival of embryos (17.3 ± 28%) in comparison to normoxic conditions (68.5 ± 25%). Moreover, larval deformities were found when exposed to hypoxia (91.6 ± 6%). During embryonic development of this species 4 mg/L of oxygen is tolerated at 26–27 C without negative impact. We conclude that despite the highly adaptable nature of adult pacu to environmental hypoxia, oxygen concentrations below 4 mg/L severely impacted survival of embryos. 相似文献
14.
The ethanolic extract from the stem of Brosimum potabile afforded (-)-centrolobin (1), isolated for the first time in this genus. The identification of this compound included COSY and NOESY two-dimensional NMR data. 相似文献
15.
Krassimir D. Naydenov Michel K. Naydenov Alexander Alexandrov Kole Vasilevski Georgi Hinkov Vlado Matevski Biljana Nikolic Venceslas Goudiaby Dave Riegert Despina Paitaridou Andreas Christou Irina Goia Christopher Carcaillet Adrian Escudero Alcantara Cengiz Ture Suleyman Gulcu Veselka Gyuleva Srdjan Bojovic Lorenzo Peruzzi Salim Kamary Anatoly Tsarev Faruk Bogunic 《European Journal of Forest Research》2017,136(5-6):767-786
The historical changes in European Black Pine population size across the whole natural distribution in Europe and Asia Minor were analyzed facing the Plio-Pleistocene climatic fluctuations. Thirteen chloroplast SSRs and SNPs markers have been studied under the assumptions of “neutral evolution.” Populations and meta-populations had different histories of migration routes, and they were strongly affected by complex patterns of isolation, fragmentation, speciation, expansion (1.88–4.28 Ma), purification selection (2.09–21.41 Ma) and bottleneck (1.85–21.76 Ma). A significant number of populations (min. 29–41%) were in equilibrium for very long periods. Generally, the bottleneck revealed by chloroplast DNA is weaker than the bottleneck revealed by nuclear DNA. The N e immediately after the bottleneck reaches between 1820 and 3640 individuals. Generally, the historical effective population sizes shrink significantly for the Tertiary period from 10–15 up to 2.5 Ma in Western Europe (by 82%), followed by Asia Minor (69%) and the Balkan Peninsula (28%), likely resulting from important climatic changes. The rates and frequencies of stepwise westwards migration waves have been not sufficient to prevent isolation between the meta-populations and to suppress “sympatric speciation.” The migration was weak for the Pliocene, but was maximal for the Pleistocene, and finally silent for the present interglacial period, namely the Holocene. 相似文献
16.
Palmira De Bellis Leonardo Schena Corrado Cariddi 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(1):11-22
A specific primer couple (E3–E4) amplifying a single DNA fragment of 111 bp from plasmid pEA29 was designed to identify, detect
and quantify Erwinia amylovora by real-time Scorpion-PCR. Specificity of primers and probe was assessed both by means of BLAST analyses and by using genomic
DNA from a large number of E. amylovora isolates and other bacteria. In Scorpion-PCR, the limit of detection was of 1 pg of total DNA and a high correlation (r = 0.999) was achieved between target DNA quantity and cycle threshold (Ct). Combining two sequential amplifications with
conventional reported primers (PEANT1–PEANT2) and Scorpion primers (E3 Scorpion-E4) the detection limit was of 1 fg (nested
Scorpion-PCR). Using serial dilution of the bacterial suspensions the limit of detection was 3.2 × 104 CFU ml−1 in Scorpion-PCR and 2.8 × 102 CFU ml−1 in nested Scorpion-PCR. Real-time PCR combined with effective procedures for DNA extraction enabled the detection and the
quantification of the epiphytic population of E. amylovora in the washings of flowers and leaves of artificially inoculated pear. A significant correlation (r = 0.92) was achieved between pathogen CFU on semi-selective media and the corresponding target DNA concentration evaluated
by real-time PCR. 相似文献
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18.
de Mello Tavares Lima Paulo da Silva Alcantara Moraes Sousa Carla Vanessa do Prado Paim Tiago Corrêa Patrícia Spoto Lanna Dante Pazzanese Duarte McManus Concepta Abdalla Adibe Luiz Louvandini Helder 《Tropical animal health and production》2019,51(4):775-780
The aim of this study was to investigate the effects of castration on carcass characteristics and fatty acid profile of visceral fat and meat from lambs. Eighteen six-month-old Santa Inês male lambs (18.9?±?2.4 kg of body weight (BW)) were used. Animals were assigned to two treatments according to their sexual condition: uncastrated (U) or castrated (C). During a 98-day experimental period, animals were kept on an Andropogon gayanus grass pasture area of 1 ha and supplemented with 200 g/animal/day of concentrate mixture. Water and mineral salt were available ad libitum. The lambs were weighed fortnightly, and at the last day of the trial, they were slaughtered for evaluation of carcass characteristics and fatty acids profile of perirenal fat and longissimus lumborum muscle samples. Castrated lambs showed higher BW than U during most part of the experiment (p?<?0.05). Fat deposition was higher in C lambs as evidenced by their increased carcass fat cover. Meat from U lambs showed lower content of C16:0 and higher polyunsaturated fatty acids (PUFA) (p?<?0.05) than that from C (U, 14.3 and C, 10.5%). Conjugated linoleic acid (CLA) content was not affected by castration (p?>?0.05) (U, 0.74 and C, 0.76%). The cis-9, cis-12 C18:2n-6 (U, 10.6 and C, 6.86%) fatty acid and the PUFA:SFA (saturated fatty acids) ratio (U, 0.36 and C, 0.25) were higher in the muscle of U lambs (p?<?0.05), indicating that the meat from U animals may provide more benefits to human health than that of C.
相似文献19.
S. Alcantara D.V. Pérez M. R. A. Almeida G.M. Silva J.C. Polidoro W. Bettiol 《Water, air, and soil pollution》2009,203(1-4):3-16
The need for solutions to minimize the negative environmental impacts of anthropogenic activities Fhas increased. Sewage sludge is composed of predominantly organic matter and can be used to improve soil characteristics, such as fertility. Therefore, its application in agriculture is an adequate alternative for its final disposal. However, there is a lack of information on its long-term effects on soil changes in tropical areas. Thus, the objectives of this study were to determine (i) the effect of sewage sludge application on heavy metal build-up in soil and maize grains and leaves, and (ii) the effects of soil amendment with sewage sludge on the chemical properties of a Brazilian oxisol. Besides the increasing levels of Zn, Cu, Ni, and Cr, amending soil with sewage sludge also alters the distribution of these metals by increasing the mobile Phases, which correlated significantly with the increase in metal extraction with two single extractants, Mehlich 1 and DTPA (Diethylene triamine pentaacetic acid). The levels of Fe, Mn, Zn, and Cu in maize grains and leaves increased with the type and rate of sewage sludge application. Nevertheless, metal build-up in soil and plants was within the allowed limits. Significant differences were also found in soil characteristics like humic fractionation with the applied sewage doses. The data obtained does not indicate any expressive drawbacks in the use of sewage sludge as a soil amendment, as the heavy metal concentrations observed are unlikely to cause any environmental or health problems, even overestimated loadings, and are in accordance with the Brazilian regulations on farming land biosolid disposal. 相似文献
20.
Jo&#;to Batista K. Fernandes Rebecca Lochmann Fernando Alcantara Bocanegra 《Journal of the World Aquaculture Society》2004,35(2):237-244
The digestible energy and apparent nutrient digestibility coefficients of common diet ingredients were determined for pacu Piaractus brachypomus (370.21 ± 17.56 g). Fish were fed with pelleted practical diets to apparent satiation and the feces were collected by siphoning. The digestibility value for each ingredient was determined by comparison of the digestibility of a test diet with a reference diet (24.5% crude protein and 1% chromic oxide). The digestible energy values of soybean meal (SBM), fish meal (FM), corn (CN), and wheat bran (WB) were 2382. 3826, 3353, and 1784 kcal/kg, respectively. The apparent dry matter digestibility coefficients were 83.72, 90.14, 89.13, and 82.05% for SBM, FM, CN, and WB, respectively. The apparent crude protein digestibility coefficients were 75.88, 90.49, 85.06, and 61.62% for SBM. FM, CN, and WB, respectively. The apparent lipid digestibility coefficients were 63.03, 77.00, 83.01, and 82.45% for SBM, FM, CN, and WB, respectively. The digestibility of protein, lipid, and energy from SBM were somewhat low compared to values for other warmwater omnivorous fishes, but similar to values reported for pacu-caranha P. mesopotamicus. Otherwise, the nutrient and energy availability of the ingredients to P. brachypomus was similar to that of other fish. This information will be useful in formulating nutritious, economical diets for pacus. 相似文献