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Tittarelli A Milla L Vargas F Morales A Neupert C Meisel L Salvo-G H Peñaloza E Muñoz G Corcuera L Silva H 《Journal of experimental botany》2007,58(10):2573-2582
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S.‐S. Chang A.R. Han J.I. Reyes‐De‐Corcuera J.R. Powers D.‐H. Kang 《Letters in applied microbiology》2010,50(4):393-398
Aim: To investigate the efficacy of steam pasteurization for reducing Salmonella serotype Enteritidis on raw almond surfaces. Methods and Results: Nonpareil almonds were inoculated to 107–8 CFU g?1 with a Salm. Enteritidis cocktail (Salm. Enteritidis 43353, ME‐13, ME‐14) or Salm. Enteritidis phage type 30, dried overnight and subjected to steam treatments through a pilot‐sized vertical pasteurization machine for 5, 15, 25, 35, 45, 55 and 65 s to investigate the effect of steam on a single layer of almond. Survival of Salm. Enteritidis was evaluated with tryptic soy agar and xylose lysine desoxycholate overlay for total and healthy cells, respectively. No significant differences (P > 0·05) in reduction were observed between the Salm. Enteritidis cocktail and Salm. Enteritidis PT 30 inoculum. Reduction of Salm. Enteritidis increased as a function of treatment time, with 25 s being sufficient to achieve a 5‐log reduction. Discolouration and visible formation of wrinkles were observed following steam pasteurization of more than 35 s. Conclusions: Steam pasteurization of 25 s is sufficient to achieve a 5‐log reduction of Salm. Enteritidis inoculated on raw almonds without visual quality degradation. Significance and Impact of the Study: Steam pasteurization is an effective alternative to reduce or prevent Salm. Enteritidis contamination on raw almonds. 相似文献
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Alejandra Zúñiga-Feest Luisa Bascuñán-Godoy Marjorie Reyes-Diaz León A. Bravo Luis J. Corcuera 《Polar Biology》2009,32(4):583-591
Deschampsia antarctica and Colobanthus quitensis are usually covered by snow from April to November. It is unknown whether the leaves survive ice encasement. This study proposes
that day length influences sugar distribution in C. quitensis and that sugar accumulation favors re-growths after an ice encasement period. The objectives of this work were: (1) to study
the effect of day length and low temperature on sugar distribution in organs of C. quitensis and (2) to study the survival and recovery of D. antarctica and C. quitensis after a period of ice encasement. Extremely short day length (SD) (8/16 h) and long day length (LD) (21/3 h) was used, medium
(MD) (16/8 h) corresponding at control day length. Also two temperatures: 4°C (cold acclimated) and 15°C (control) were evaluated.
Both factors: day length and cold acclimation significantly affected sugar distribution in C. quitensis. Both species presented a high rate of survival after ice encasement. D. antarctica conserved most of their leaves green, while C. quitensis presented dead leaves and new shoots in plants from cold acclimated under SD. Only in D. antarctica the number of green leaves after ice encasement was positively correlated with sugar content in underground organs. The high
sugar content in green leaves of both species suggested fast activity recovery after snow melting. 相似文献
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Spatial and temporal variation in citrate and malate exudation and tissue concentration as affected by P stress in roots of white lupin 总被引:1,自引:1,他引:0
Exudation of carboxylates represents one the most efficient strategies used by P-starved white lupin (Lupinus albus L.) to acquire phosphorus from sparingly soluble sources. This exudation occurs through proteoid root clusters, with citrate being the predominant organic acid released. The occasional detection of malate in whole root exudates suggests that this acid would also be released, but from tissues other than root clusters. To investigate the spatial and temporal pattern of exudation, citrate and malate exudation and concentration were measured in whole roots and root sections of white lupin, from seedling emergence to plant senescence due to P starvation. Both organic acids were detected in whole root exudates of P-stressed plants, and they were released at similar rates throughout the experiment. Malate was predominantly exuded from apices of both seedling taproots and proteoid roots, whereas citrate exudation was restricted to proteoid root clusters. Studies directed to address the association between carboxylate exudation and concentration in proteoid root clusters showed a non-linear response for citrate, within the range of 7 to 23 mol g–1 fresh weight. This association was further assessed by altering citrate concentration in the whole root. Adding P to 24-day-old P-starved plants reduced citrate concentration and exudation to the level of the control P-fed plants, demonstrating that citrate exudation and concentration are associated. Malate exudation and concentration did not correlate significantly. Results indicate that citrate release by P-starved white lupin would occur whenever a certain threshold of citrate concentration is attained, and that the sites, the rates and the span of transient exudation depend on the physiological age of the tissue. 相似文献
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Quantitation of 1,4-Benzoxazin-3-ones in Maize by Gas-Liquid Chromatography 总被引:2,自引:1,他引:1 下载免费PDF全文
A gas-liquid chromatographic (GLC) procedure is reported for the quantitation of the trimethylsilyl (TMS) derivatives of substituted 2-hydroxy-2H-1,4-benzoxazin-3(4H)-ones (2-hydroxy-2H-1,4-benzoxazin-3(4H)-one[HBOA]; 2-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one[HMBOA];2,4- dihydroxy-2H-1,4-benzoxazin-3(4H)-one[DIBOA]; 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one[DIMBOA]; and 2,4-dihydroxy-7,8-dimethoxy-2H-1,4-benzoxazin-3(4H)-one[DIM 2BOA]) found in maize (Zea mays L.) extracts. Derivatized samples were chromatographed on columns with liquid phases of 2% DC-11 and 3% OV-17 and detected by flame ionization. Internal standards were methyl palmitate and methyl stearate on DC-11 and methyl behenate on OV-17. Detector response was linear to at least 5 nanomoles for TMS2-HBOA and TMS2-DIBOA and to 19 nanomoles for TMS2-DIMBOA. Standard errors of 2% or less were obtained when four replicate samples were analyzed. For each of the 15 maize lines examined, the amount of DIMBOA determined by GLC was directly proportional to the amount of ferric chloride-reactive material determined colorimetrically. 相似文献
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Luis J. Corcuera 《Phytochemistry》1984,23(3):539-541
The indole bases N∞-methyltryptamine, 5-methoxy-N, N-dimethyltryptamine, 3-N,N-dimethylaminomethylindole (gramine) and 5-methoxytryptamine decreased survival of nymphs of Rhopalosiphum maidis with LD50 of 3.8, 3.5, 2.9 and 2.3 mM, respectively, after 48 hr of feeding with a synthetic diet. Gramine also decreased survival of Schizaphis graminum with an LD50 of 0.7 mM after 48 hr of feeding. The four compounds tested showed feeding deterrent activity on the aphids at concentrations as low as 0.5 mM. In addition, gramine showed toxic effects on S. graminum. Since the deleterious effects of gramine and related compounds in synthetic diets are observed at concentrations similar to those found in plants, it is possible that these molecules may have a role in protecting the plant against aphids 相似文献
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Leyre Corcuera Hervé Cochard Eustaquio Gil-Pelegrin Eduardo Notivol 《Trees - Structure and Function》2011,25(6):1033-1042
The objectives of the study were to assess the phenotypic variation in the vulnerability to water stress-induced cavitation
(estimated by P50, or the xylem water potential which causes a 50% loss of conductivity) and the trade-offs between P50 and related hydraulic traits, i.e., stem specific conductivity (K
s), slope of the vulnerability curve (slope), wood density and branch size. Variability was examined for six Pinus pinaster populations covering the latitudinal range of the species and plasticity was tested through two provenance-progeny trial
sites (xeric/mesic). As expected, the overall values of P50, K
s and branch size decreased in the xeric site. Variation in P50 and K
s among populations was mainly the result of phenotypic plasticity, while wood density was genetically controlled and not affected
by the environment. Stress conditions in the xeric site promoted a convergence in P50 and K
s as a result of the high phenotypic plasticity of the populations from mesic origins. In the mesic site, the ranking of populations
for cavitation resistance and hydraulic capacity was consistent with the geographic location of the seed source. Higher resistance
to cavitation was related to lower K
s, branch size and slope, mainly at the population level, but also as a general trend across individuals. In a warmer and drier climate, there could
be a potential selection of Pinus pinaster populations from mesic origins, which showed a great responsiveness and adjustment to drought conditions (similar or higher
P50 than the populations from dry origins), in addition to a high wood density and growth. 相似文献