Soil P fractions in a volcanic soil chronosequence of Central Mexico and their relationship to foliar P in pine trees   总被引：1，自引：0，他引：1       下载免费PDF全文

Nadeshda Cosette Galván‐Tejada  Víctor Peña‐Ramírez  Lucy Mora‐Palomino  Christina Siebe 《植物养料与土壤学杂志》2014,177(5):792-802

Phosphorus (P) is a major plant nutrient, however, its availability in volcanic ash soils is presumed to be small, due to its specific sorption on short‐range order minerals. We analyzed distinct P fractions in volcanic ash soils of different age (60 to > 100,000 y BP) under pine forests in Central Mexico to investigate their changes along a chronosequence of Regosols, Andosols, and Lixisols, and to evaluate if P availability limits tree growth at any particular stage. Top soil and subsoil samples were first analyzed by the Tiessen and Moir method, which failed to extract exhaustively “organic” and “occluded P”, and “P associated with apatite”. Therefore, we modified the fractionation scheme by including a “recalcitrant organic P” fraction obtained from the difference between P determined in air‐dried subsamples and subsamples burned at 300°C; P adsorbed to short‐range order minerals was assessed in an extraction with NH₄‐oxalate, and P in primary minerals by subtracting the sum of all other fractions from total P contents determined by XRF. This we did after discovering that primary P occurred in the form of fluorapatite included in plagioclase, volcanic glass or olivine. We also measured P contents in pine needles and related these with the “mobile soil P” fractions. The results show that “organic P” reaches maximum contents in 10,000‐y old soil, as does P associated with short‐range order minerals, while P occluded into crystalline oxides increases constantly over time. After 100,000 y, 31% of total P still remains in the form of primary P in A horizons. “Mobile P” was constant > 40 mg kg^?1 in Regosols and Andosols and related positively with foliar P contents, which were within adequate nutritional ranges. Only in Lixisols small “mobile P” concentrations in soil correspond with inadequate P contents in pine needles.  相似文献   

Cyclooxygenase-2 expression is related with localization, proliferation, and overall survival in canine melanocytic neoplasms     

Martínez CM  Peñafiel-Verdú C  Vilafranca M  Ramírez G  Méndez-Gallego M  Buendía AJ  Sánchez J 《Veterinary pathology》2011,48(6):1204-1211

A direct relationship has been firmly established between cyclooxygenase-2 (COX-2) expression and malignant behavior in human melanoma. This report examines the relationship between COX-2 expression and tumor location, mitotic and proliferative indices, degree of T CD3(+) lymphocyte infiltration, overall survival, and frequency of recurrence and metastasis of 57 melanocytic tumors (25 oral and 32 cutaneous). COX-2 was highly or moderately expressed in 88% of oral neoplasms (22 of 25), whereas for their cutaneous counterparts, COX-2 expression was low or insignificant in 75% of cases (24 of 32). High and moderate COX-2 expression levels were observed in 73% of melanocytic tumors with a mitotic index ≥ 3 per 10 high-power fields (26 of 36), whereas in 81% of tumors with a mitotic index < 3 (17 of 21), expression was mild or absent. There were 41 cases with known clinical outcomes; of those showing high, moderate, and mild COX-2 expression, 83.3% (10 of 12), 37.5% (3 of 8), and 25% (2 of 8) died, respectively, whereas 100% of animals showing no COX-2 expression (13 of 13) were still alive at the last follow-up. COX-2 expression was statistically correlated with tumor location, mitotic and percentage Ki-67 proliferative indices, and overall survival, frequency of neoplastic recurrence and metastasis. Regression analysis also showed disease-specific predictive value for COX-2 expression for subjects with melanocytic neoplasms. Additionally, only high COX-2 expression showed significant differences in overall survival, in comparison with moderate, mild, or absent expression. These results suggest that high COX-2 expression may be considered a prognostic biomarker and potentially as a target for therapeutic and preventive strategies in canine melanocytic neoplasms.  相似文献   

Classification and grading of canine mammary tumors     

Goldschmidt M  Peña L  Rasotto R  Zappulli V 《Veterinary pathology》2011,48(1):117-131

Mammary neoplasms are the most common neoplasm in female dogs. Two histologic classification systems for canine mammary tumors and dysplasias have been published: the first in 1974 and a modification in 1999. This article provides a brief overview of the two histologic classification systems. Since the publication of the second system, several new histologic subtypes of canine mammary neoplasms have been described. These have been incorporated into the proposed new classification system. This article also compares the grading systems for canine mammary carcinomas and their use for prognosis, along with the histologic classification.  相似文献   

Influence of two-phase olive mill waste application to soil on terbuthylazine behaviour and persistence under controlled and field conditions     

Antonio López-Piñeiro  Damaso Cabrera  Ángel Albarrán  David Peña 《Journal of Soils and Sediments》2011,11(5):771-782

Purpose  

Terbuthylazine is one of the most common herbicides used to control weeds in olive groves. Application of two-phase olive mill waste (OW) to soils may play a fundamental role in the management of leaching losses of pesticides, especially in Mediterranean areas where soils are characterized by low organic matter levels. We evaluated the impact of OW amendments on the sorption–desorption, degradation, leaching, and persistence of the herbicide terbuthylazine in a representative olive grove soil from Portugal.  相似文献   

In vitro development of IVF-derived bovine embryos following cytoplasmic microinjection for the episomal expression of the IGF2 gene     

Karine Campagnolo  Felipe Ledur Ongaratto  Camila Rodrigues de Freitas  Camilo Andrés Peña Bello  Bruna Rodrigues Willhelm  Karine de Mattos  José Luiz Rigo Rodrigues  Marcelo Bertolini 《Reproduction in domestic animals》2020,55(5):574-583

Important genomic imprinting changes usually occur following the in vitro production (IVP) of bovine embryos, especially in the imprinting pattern of components of the IGF system. This study aimed to evaluate the effects of a transient episomal overexpression of the IGF2 gene in bovine IVP embryos following embryo cytoplasmic microinjection (CMI) at the 1-cell stage on embryo survival, early and late developmental kinetics and morphological quality up to Day 7 of development. Selected cumulus–oocyte complexes (COCs) were matured and fertilized in vitro and subsequently segregated into six experimental groups: non-CMI control group and five CMI groups at increasing doses (0, 10, 20, 40 and 80 ng/μl) of a GFP vector built for the episomal expression of bovine IGF2. Zygote CMI was effective in delivering the expression vector into the ooplasm, irrespective of the groups, with 58% of positive GFP fluorescence in Day 7 blastocysts. Considering developmental rates and late embryo kinetics, the 10-ng/μl CMI vector dose promoted a lower blastocyst rate (10.4%), but for blastocysts at more advanced stages of development (93.0% blastocysts and expanded blastocysts), and higher number of cells (116.0 ± 3.0) than non-CMI controls (23.3%, 75.0% and 75.0 ± 6.8 were obtained, respectively). In conclusion, CMI at the 1-cell stage did not compromise subsequent in vitro development of surviving embryos, with the 10-ng/μl group demonstrating a possible growth-promoting effect of the IGF2 gene on embryo development, from the 1-cell to the blastocyst stage.  相似文献   

Soil erosion modelling of burned and mulched soils following a Mediterranean forest wildfire     

Javier Gonzalez-Romero  Demetrio Antonio Zema  Bruno Gianmarco Carrà  Jonay Neris  Alvaro Fajardo  Pedro Antonio Plaza-Álvarez  Daniel Moya  Esther Peña-Molina  Jorge de las Heras  Manuel Esteban Lucas-Borja 《Soil Use and Management》2023,39(2):881-899

Soil erosion modelling applied to burned forests in different global regions can be unreliable because of a lack of verification data. Here, we evaluated the following three erosion models: (1) Water Erosion Prediction Project (WEPP), (2) Morgan-Morgan-Finney (MMF) and (3) Universal Soil Loss Equation-Modified (USLE-M). Using field plots that were either untreated or mulched with straw, this study involved observations of soil loss at the event scale at a burned pine forest in Central Eastern Spain. The erosion predictions of the three models were analysed for goodness-of-fit. Optimization of the MMF model with a new procedure to estimate the C-factor resulted in a satisfactory erosion prediction capacity in burned plots with or without the mulching treatment. The WEPP model underestimated erosion in the unburned areas and largely overestimated the soil loss in burned areas. The accuracy of soil loss estimation by the USLE-M model was also poor. Calibration of the curve numbers and C-factors did not improve the USLE-M model estimation. Therefore, we conclude that an optimized MMF model was the most accurate way to estimate soil loss and recommend this approach for in Mediterranean burned forests with or without postfire mulching. This study gives land managers insight about the choice of the most suitable model for erosion predictions in burned forests.  相似文献   

Production of transgenic adult plants from clementine mandarin by enhancing cell competence for transformation and regeneration   总被引：3，自引：0，他引：3  

Cervera M  Navarro A  Navarro L  Peña L 《Tree physiology》2008,28(1):55-66

Genetic transformation of mature trees is difficult because adult tissues are recalcitrant to Agrobacterium tumefaciens infection and transformation and because transgenic mature events are less competent for regeneration. We have shown that reinvigoration allows manipulation of the vegetative phase to increase the potential for transformation and regeneration without loss of competence for flowering and fruiting. To produce transgenic plants from clementine mandarin (Citrus clementina hort. ex Tanaka), we optimized the conditions of the source material both ex vitro and in vitro. Grafting of mature buds on juvenile rootstocks in the spring and preventing multiple bud sprouting by removing all but one bud permitted selection of vigorous first flushes for in vitro culture. Use of additional virulence genes from A. tumefaciens to increase transformation frequency and optimization of culture media and conditions to enhance explant cell competence for T-DNA integration and organogenesis resulted in efficient and reliable transgenic plant production. Transformed regenerants from explants, cultured in media without antibiotics, were identified by a screenable marker (either beta-glucuronidase or green fluorescent protein (GFP)), creating the possibility of generating transgenic clementine plants without antibiotic resistance marker genes. Stable integration of foreign genes was demonstrated by Southern blot analysis, and expression of these foreign genes was confirmed by detection of GFP fluorescence in leaves, floral organs and fruits of the transgenic plants.  相似文献   

Differential effects of phytotoxic metabolites from <Emphasis Type="Italic">Alternaria tagetica</Emphasis> on <Emphasis Type="Italic">Tagetes erecta</Emphasis> cell cultures     

Joaquin A. Qui  Lizbeth A. Castro-Concha  Karlina García-Sosa  Luis Manuel Peña-Rodríguez  María L. Miranda-Ham 《Journal of General Plant Pathology》2009,75(5):331-339

Alternaria tagetica, a fungus that causes early blight in marigold (Tagetes erecta), produces two groups of phytotoxic metabolites: one hydrophilic and the other lipophilic that show phytotoxic activity when tested by the leaf-spot assay in T. erecta. We evaluated the cellular effects of the phytotoxic culture filtrate of A. tagetica and the hydrophilic and lipophilic fractions, then determined whether the filtrate or the fractions differentially induced pathogenesis-related mechanisms in the plant. The culture filtrate and the phytotoxic fractions had adverse effects on cell viability, fresh mass, and the number of cells, and induced ROS accumulation, lipid peroxidation and DNA damage on T. erecta cell suspension cultures, and these effects are related to pathogenic mechanisms attributed to phytotoxins. However, although exposure of marigold cells to the phytotoxic culture filtrate of A. tagetica triggered programmed cell death, the hydrophilic and the lipophilic phytotoxic fractions induced death that was more related to a toxic effect leading to necrosis. This study presents a complementary perspective in the search for the roles of metabolites, including phytotoxins, produced by phytopathogenic fungi during plant infection.  相似文献   

Effects of age and breed on corneal thickness,density, and morphology of corneal endothelial cells in enucleated sheep eyes          下载免费PDF全文

Natalia Coyo  Maria Teresa Peña  Daniel Costa  José Ríos  Rodrigo Lacerda  Marta Leiva 《Veterinary ophthalmology》2016,19(5):367-372

  相似文献   

The acute phase response induced by Escherichia coli lipopolysaccharide modifies the pharmacokinetics and metabolism of florfenicol in rabbits          下载免费PDF全文

R. Pérez  C. Palma  R. Burgos  J. A. Jeldres  A. Espinoza  A. K. Peñailillo 《Journal of veterinary pharmacology and therapeutics》2016,39(2):183-190

The aim of this study was to determine the effect of Escherichia coli lipopolysaccharide (LPS)‐induced acute phase response (APR) on the pharmaco‐kinetics and biotransformation of florfenicol (FFC) in rabbits. Six rabbits (3.0 ± 0.08 kg body weight (bw)) were distributed through a crossover design with 4 weeks of washout period. Pairs of rabbits similar in bw and sex were assigned to experimental groups: Group 1 (LPS) was treated with three intravenous doses of 1 μg/kg bw of E. coli LPS at intervals of 6 h, and Group 2 (control) was treated with an equivalent volume of saline solution (SS) at the same intervals and frequency of Group 1. At 24 h after the first injection of LPS or SS, an intravenous bolus of 20 mg/kg bw of FFC was administered. Blood samples were collected from the auricular vein before drug administration and at different times between 0.05 and 24.0 h after treatment. FFC and florfenicol‐amine (FFC‐a) were extracted from the plasma, and their concentrations were determined by high‐performance liquid chromatography. A noncompartmental pharmacokinetic model was used for data analysis, and data were compared using the paired Student t‐test. The mean values of AUC_0–∞ in the endotoxaemic rabbits (26.3 ± 2.7 μg·h/mL) were significantly higher (P < 0.05) than values observed in healthy rabbits (17.2 ± 0.97 μg·h/mL). The total mean plasma clearance (CL_T) decreased from 1228 ± 107.5 mL·h/kg in the control group to 806.4 ± 91.4 mL·h/kg in the LPS‐treated rabbits. A significant increase (P < 0.05) in the half‐life of elimination was observed in the endotoxaemic rabbits (5.59 ± 1.14 h) compared to the values observed in healthy animals (3.44 ± 0.57 h). In conclusion, the administration of repeated doses of 1 μg/kg E. coli LPS induced an APR in rabbits, producing significant modifications in plasma concentrations of FFC leading to increases in the AUC, terminal half‐life and mean residence time (MRT), but a significant decrease in CL_T of the drug. As a consequence of the APR induced by LPS, there was a reduction in the metabolic conversion of FFC to their metabolite FFC‐a in the liver, suggesting that the mediators released during the APR induced significant inhibitory effects on the hepatic drug‐metabolizing enzymes.  相似文献