Impact of soil water content on maize responses to the plant growth-promoting rhizobacterium Azospirillum lipoferum CRT1     

Sonia Czarnes  Pierre-Edouard Mercier  Damien G. Lemoine  Jihane Hamzaoui  Laurent Legendre 《Journal of Agronomy and Crop Science》2020,206(5):505-516

Members of the bacterial genus Azospirillum are root-associated bacteria that increase yield in cereals by promoting growth and alleviating drought stress. How plants integrate the many bacterium-derived growth-promoting stimuli with other environmental factors to generate a coordinated response remains unresolved. Using a commercial Azospirillum strain, A. lipoferum CRT1 and two host maize cultivars, it was observed that bacterization reduced the drought-induced increase in lateral root growth and enhanced the flood-induced increase in lateral root growth in the more drought- and flood-sensitive cultivar. In the other one, A. lipoferum CRT1 only elicited a moderate root growth response under low soil water potential. The photosynthetic potential and activity were increased in the earlier cultivar and decreased in the later one, irrespective of the soil water content. No impact of the bacterium was seen on the growth of the leaves of both cultivars under both stresses until the third leaf stage, therefore suggesting that it is a consequence of multiple primary adaptations to biotic and abiotic stresses. It is suggested that host–bacteria recognition leads to a stress-specific modulation of the root response and a differential stress-independent effect on photosynthesis. This is the first report of the impact of Azospirillum under flood conditions.  相似文献   

ELISA to detect proteolysis of ultrahigh-temperature milk upon storage     

Dupont D  Lugand D  Rolet-Repecaud O  Degelaen J 《Journal of agricultural and food chemistry》2007,55(17):6857-6862

Casein proteolysis can occur in milk during storage leading to its gelation. The two main proteolytic systems suspected to be involved are the plasmin and the proteases produced by psychrotrophic bacteria. The latter have been shown to cleave kappa-casein at the Phe105-Met106 bond. Although several techniques allow the determination of plasmin in milk, few rapid and easy-to-perform analytical techniques are available to check for bacterial proteolytic activity. This study presents the development of an inhibition ELISA allowing for the quantification of the kappa-casein intact at the Phe105-Met106 bond. It uses a monoclonal antibody specifically directed against this peptide bond that binds to the protein as long as the molecule's cleavage site is intact but not when it is cleaved. This simple technique allows for the rapid analysis of more than 20 samples within 3 h. Applied to commercial milks, this assay allowed for the detection of unstable milk.  相似文献   

Optimal conditions for egg storage, incubation and post-hatching growth for the freshwater turtle, Chelodina rugosa: Science in support of an indigenous enterprise     

Damien A. Fordham  Arthur Georges  Ben Corey 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):105-114

Incubation of northern snake-necked turtle (Chelodina rugosa) eggs and subsequent sale of hatchlings for the pet industry has the potential to provide culturally suitable employment for indigenous communities in northern Australia. Developmental arrest in response to egg inundation is unique to C. rugosa. Eggs can be stored under water for up to 10 weeks without appreciable impact on egg or embryo survival, allowing the transport and sale of eggs into niche markets without high levels of mortality, and permitting eggs to accumulate in diapause until there are sufficient numbers to incubate as batches. Eggs that are not inundated or inundated for short periods experience similar survival rates to eggs inundated for lengthy periods. Incubation temperature influences embryo survival and development period in C. rugosa. Embryonic survival is greatest at 26 °C, steadily declining as temperature increases to 32 °C. A similar increase in incubation temperature decreases incubation period by approximately 40 days, however almost half of this variation is attributed to the increase in incubation temperature from 26 to 28 °C. Hatchling growth in C. rugosa is characterized by two phases. There is an initial phase of relatively slow growth under the partial influence of initial egg size and incubation duration, followed by a second phase of relatively rapid growth under the partial influence of water temperature and mass at hatching. Post-hatching survival is negatively correlated with duration of egg inundation and water temperature. Evidence suggests that inundation of C. rugosa eggs for 6 weeks, incubation of embryos at 28 °C and raising hatchlings in 28 °C water will yield the best overall outcomes.  相似文献   

Development of structure-taste relationships for monosubstituted phenylsulfamate sweeteners using classification and regression tree (CART) analysis     

Kelly DP  Spillane WJ  Newell J 《Journal of agricultural and food chemistry》2005,53(17):6750-6758

Twenty monosubstituted phenylsulfamates (cyclamates) have been synthesized and have had their taste portfolios determined. These have been combined with 63 compounds already in the literature to give a database of 83 ortho, meta, and para compounds. A training set of 75 compounds was randomly selected leaving eight compounds as a test set. A series of nine predictors determined with Corey-Pauling-Koltun models, calculated from the PC SPARTAN PRO program and Hammett sigma values taken mainly from the literature, have been used to establish structure-taste relationships for these types of sweeteners. The taste panel data for all compounds were categorized into three classes, namely, sweet (S), nonsweet (N), and sweet/nonsweet (N/S), and a novel "sweetness value" or weighting was also calculated for each compound. Linear and quadratic discriminant analysis were first used with the S, N, and N/S data, but the results were somewhat disappointing. Classification and regression tree analysis using the sweetness values for all 75 compounds was more successful, and only 14 were misclassified and six of the eight test set compounds were correctly classified. For the 29 meta compounds, one subset using just two parameters classified 83% of these compounds. Finally, using various methods, predictions were made on the likely tastes of a number of meta compounds and a striking agreement was found between the tree prediction and those given by earlier models. This appears to offer a strong vindication of the tree approach.  相似文献   

Association of TALS developmental disorder with defect in minor splicing component U4atac snRNA     

Edery P  Marcaillou C  Sahbatou M  Labalme A  Chastang J  Touraine R  Tubacher E  Senni F  Bober MB  Nampoothiri S  Jouk PS  Steichen E  Berland S  Toutain A  Wise CA  Sanlaville D  Rousseau F  Clerget-Darpoux F  Leutenegger AL 《Science (New York, N.Y.)》2011,332(6026):240-243

The spliceosome, a ribonucleoprotein complex that includes proteins and small nuclear RNAs (snRNAs), catalyzes RNA splicing through intron excision and exon ligation to produce mature messenger RNAs, which, in turn serve as templates for protein translation. We identified four point mutations in the U4atac snRNA component of the minor spliceosome in patients with brain and bone malformations and unexplained postnatal death [microcephalic osteodysplastic primordial dwarfism type 1 (MOPD 1) or Taybi-Linder syndrome (TALS); Mendelian Inheritance in Man ID no. 210710]. Expression of a subgroup of genes, possibly linked to the disease phenotype, and minor intron splicing were affected in cell lines derived from TALS patients. Our findings demonstrate a crucial role of the minor spliceosome component U4atac snRNA in early human development and postnatal survival.  相似文献   

Prevalence of pathogens causing subclinical mastitis in 15 dairy herds in the Republic of Ireland   总被引：1，自引：0，他引：1  

Barrett DJ  Healy AM  Leonard FC  Doherty ML 《Irish veterinary journal》2005,58(6):333-337

: Milk samples from 285 cows in 15 dairy herds were collected for bacteriological analysis. Cows were selected on the basis of a somatic cell count (SCC) exceeding 200,000 cells per ml at the three most recent milk recordings prior to sampling. Staphylococcus aureus and Streptococcus uberis were the predominant isolates accounting for 21% (n = 61) and 19% (n = 53) of isolates, respectively. Streptococcus uberis was more frequently isolated from split-calving herds than from spring-calving herds and this difference was statistically significant (P < 0.005). Herds with suboptimal housing had a significantly greater prevalence of S. uberis than did herds where housing was adequate (P < 0.005). The isolation rates for S. aureus was significantly greater in herds where parlour hygiene was suboptimal (P < 0.05).  相似文献   

Global mineralogical and aqueous mars history derived from OMEGA/Mars Express data     

Bibring JP  Langevin Y  Mustard JF  Poulet F  Arvidson R  Gendrin A  Gondet B  Mangold N  Pinet P  Forget F  Berthé M  Bibring JP  Gendrin A  Gomez C  Gondet B  Jouglet D  Poulet F  Soufflot A  Vincendon M  Combes M  Drossart P  Encrenaz T  Fouchet T  Merchiorri R  Belluci G  Altieri F  Formisano V  Capaccioni F  Cerroni P  Coradini A  Fonti S  Korablev O  Kottsov V  Ignatiev N  Moroz V  Titov D  Zasova L  Loiseau D  Mangold N  Pinet P  Douté S  Schmitt B  Sotin C  Hauber E  Hoffmann H  Jaumann R  Keller U  Arvidson R  Mustard JF  Duxbury T 《Science (New York, N.Y.)》2006,312(5772):400-404

Global mineralogical mapping of Mars by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument on the European Space Agency's Mars Express spacecraft provides new information on Mars' geological and climatic history. Phyllosilicates formed by aqueous alteration very early in the planet's history (the "phyllocian" era) are found in the oldest terrains; sulfates were formed in a second era (the "theiikian" era) in an acidic environment. Beginning about 3.5 billion years ago, the last era (the "siderikian") is dominated by the formation of anhydrous ferric oxides in a slow superficial weathering, without liquid water playing a major role across the planet.  相似文献   

Measuring and modelling the actual energy involved in aggregate breakdown     

ZhaoLong Zhu  Damien J. Field  Budiman Minasny 《CATENA》2010

This work investigates the distribution of soil aggregates for Vertisols and Ferrasols as a function of the actual energy involved in dispersion, known as the dispersive energy. For Vertisols showing an aggregate hierarchy, the breakdown of aggregates 2–50 μm is modelled using the aggregate liberation and dispersion characteristic curve indicating a stepwise breakdown of soil aggregates. Meanwhile, for Ferrasols, the breakdown of 2–50 μm aggregates increases monotonically with increasing dispersive energy, which is indicative of the direct release of silt and clay from the disruption of aggregates. For soils displaying an aggregate hierarchy, the relative rate constant of aggregate liberation is much larger than the relative rate constant of the aggregate dispersion. Furthermore, the redistribution of aggregates for a number of size ranges within the 2–50 μm fraction illustrates a number of different pathways in aggregate breakdown, and the assumption that aggregates follow an exponential decay may not detect the presence of a weakly expressed aggregate hierarchy. The exponential decrease in ultrasonic power over time for the Ferrasols, as opposed to the prominent drop or steps in the curves for the Vertisols, confirms the lack of a prominent aggregate hierarchy.  相似文献   

Effects of esmolol on systemic hemodynamics and heart rate variability measured using the Analgesia/Nociception Index in resuscitated piglets with Pseudomonas aeruginosa septic shock          下载免费PDF全文

Emmanuel Boselli MD  PhD  Matthias Jacquet‐Lagrèze MD  Jean‐Yves Ayoub DVM  Lionel Bouvet MD  PhD  Olivier Dauwalder PharmD  PhD  Christelle Mansour DVM  Thomas Margez Eng  Christian Paquet Eng  Damien Restagno MSc  Bernard Allaouchiche MD  PhD  Jeanne‐Marie Bonnet‐Garin DVM  PhD  Stéphane Junot DVM  PhD 《Journal of Veterinary Emergency and Critical Care》2018,28(5):447-456

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Estimating nocturnal ecosystem respiration from the vertical turbulent flux and change in storage of CO₂     

Eva van Gorsel  Nicolas Delpierre  Ray Leuning  Andy Black  J. William Munger  Steven Wofsy  Marc Aubinet  Christian Feigenwinter  Jason Beringer  Damien Bonal  Baozhang Chen  Jiquan Chen  Robert Clement  Kenneth J. Davis  Ankur R. Desai  Danilo Dragoni  Sophia Etzold  Thomas Grünwald  Lianhong Gu  Bernhard Heinesch  Lucy R. Hutyra  Wilma W.P. Jans  Werner Kutsch  B.E. Law  Monique Y. Leclerc  Ivan Mammarella  Leonardo Montagnani  Asko Noormets  Corinna Rebmann  Sonia Wharton 《Agricultural and Forest Meteorology》2009,149(11):1919

Micrometeorological measurements of nighttime ecosystem respiration can be systematically biased when stable atmospheric conditions lead to drainage flows associated with decoupling of air flow above and within plant canopies. The associated horizontal and vertical advective fluxes cannot be measured using instrumentation on the single towers typically used at micrometeorological sites. A common approach to minimize bias is to use a threshold in friction velocity, u_*, to exclude periods when advection is assumed to be important, but this is problematic in situations when in-canopy flows are decoupled from the flow above. Using data from 25 flux stations in a wide variety of forest ecosystems globally, we examine the generality of a novel approach to estimating nocturnal respiration developed by van Gorsel et al. (van Gorsel, E., Leuning, R., Cleugh, H.A., Keith, H., Suni, T., 2007. Nocturnal carbon efflux: reconciliation of eddy covariance and chamber measurements using an alternative to the u_*-threshold filtering technique. Tellus 59B, 397–403, Tellus, 59B, 307-403). The approach is based on the assumption that advection is small relative to the vertical turbulent flux (F_C) and change in storage (F_S) of CO₂ in the few hours after sundown. The sum of F_C and F_S reach a maximum during this period which is used to derive a temperature response function for ecosystem respiration. Measured hourly soil temperatures are then used with this function to estimate respiration R_Rmax. The new approach yielded excellent agreement with (1) independent measurements using respiration chambers, (2) with estimates using ecosystem light-response curves of F_c + F_s extrapolated to zero light, R_LRC, and (3) with a detailed process-based forest ecosystem model, R_cast. At most sites respiration rates estimated using the u_*-filter, R_ust, were smaller than R_Rmax and R_LRC. Agreement of our approach with independent measurements indicates that R_Rmax provides an excellent estimate of nighttime ecosystem respiration.  相似文献