Aphid-borne viruses infecting cultivated watermelon and squash in Spain: Characterization of a variant of cucurbit aphid-borne yellows virus (CABYV)     

M. Pilar Rabadán  Miguel Juárez  Celia De Moya-Ruiz  Pedro Gómez 《Plant pathology》2021,70(6):1476-1485

Aphid-borne viruses are responsible for major cucurbit diseases and hamper the sustainability of crop production. Systematic monitoring can reveal the occurrence and distribution of these viruses, in addition to unadvertised viruses, facilitating the control of diseases. For three consecutive (2018–2020) seasons, the presence of aphid-borne viruses was monitored from a total of 292 samples of watermelon and squash plants that showed yellowing symptoms in three major cucurbit-producing areas (Castilla La-Mancha, Alicante, and Murcia) in Spain. We observed that cucurbit aphid-borne yellows virus (CABYV) was the most common virus found (29%) in the plants from both crops. Likewise, except for squash samples from Castilla La-Mancha and Alicante, watermelon mosaic virus (WMV) was also found (23%) with a relatively high frequency. Furthermore, we observed the exacerbation of bright yellowing symptoms in watermelon plants that was often accompanied by considerable fruit abortion. CABYV was the only causative agent for this new yellowing disease, and two infectious cDNA clones (one from watermelon, CABYV-LP63, and another from melon, CABYV-MEC12.1) were constructed to further compare and characterize this CABYV disease. Based on the full-length genome, both isolates were grouped phylogenetically together within the Mediterranean clade. However, the Koch's postulates tests were only successfully completed for the LP63 isolate, which also showed several amino acid changes and two potential recombination events, as compared to MEC12.1. Remarkably, the LP63 isolate caused more severe symptoms and showed higher RNA accumulation than MEC12.1 in five cucurbit plant species. These results suggest that a novel CABYV variant that causes severe yellowing symptoms may be causing outbreaks in cucurbit crops.  相似文献   

Ciprofloxacin Resistance in Domestic Wastewater Treatment Plants     

Celia M. Manaia  Ana Novo  Bruno Coelho  Olga C. Nunes 《Water, air, and soil pollution》2010,208(1-4):335-343

The potential of domestic wastewater treatment plants to contribute for the dissemination of ciprofloxacin-resistant bacteria was assessed. Differences on bacterial counts and percentage of resistance in the raw wastewater could not be explained on basis of the size of the plant or demographic characteristics of population served. In contrast, the treated effluent of the larger plants had significantly more heterotrophs and enterobacteria, including ciprofloxacin-resistant organisms, than the smaller (p?<?0.01). Moreover, longer hydraulic retention times were associated with significantly higher percentages of resistant enterobacteria in the treated effluent (p?<?0.05). Independently of the size or type of treatment used, domestic wastewater treatment plants discharged per day at least 10¹⁰–10¹⁴ colony forming units of ciprofloxacin-resistant bacteria into the receiving environment.  相似文献   

Norflurazon mobility, dissipation, activity, and persistence in a sandy soil as influenced by formulation     

Sopeña F  Maqueda C  Morillo E 《Journal of agricultural and food chemistry》2007,55(9):3561-3567

Five ethylcellulose (EC) microencapsulated formulations (MEFs) of norflurazon were prepared and applied in soil to study their mobility, dissipation, activity, and persistence. The results show that the release into water of norflurazon from EC microspheres was retarded when compared with that of commercial herbicide. The mobility of norflurazon from MEFs into soil columns has been greatly diminished in comparison with that of its current commercial formulation (CF). Norflurazon distribution at different depths in the soil was higher in the upper ring (up to 50% of the initial application). In contrast, the residues from commercial norflurazon along the complete soil column were only about 2%. Degradation and bioassay experiments showed that the MEFs had greater persistence (t1/2 values were 7.72 and 30.83 weeks for CF and MEFs, respectively) and herbicidal activity than the commercial formulation. The use of these formulations can be advantageous, because they can minimize the risk of groundwater contamination and permit herbicide use at reduced rates, maintaining the desired concentrations of herbicide in the topsoil layer for longer periods of weed control.  相似文献   

Ethylcellulose formulations for controlled release of the herbicide alachlor in a sandy soil   总被引：1，自引：0，他引：1  

Sopeña F  Cabrera A  Maqueda C  Morillo E 《Journal of agricultural and food chemistry》2007,55(20):8200-8205

The development of controlled-release formulations of alachlor to diminish its leaching in sandy soils, avoiding groundwater contamination and maintaining its efficacy, was studied. For this purpose, ethylcellulose (EC) microencapsulated formulations (MEFs) of alachlor were prepared under different conditions and applied to soil columns to study their mobility. The results show that in all cases the release into water of alachlor from MEFs was retarded when compared with commercial formulation. Total leaching losses in soil columns were reduced to 59% from 98%. The mobility of alachlor from EC microspheres into soil columns has been greatly diminished in comparison with its current commercial formulation (CF), above all with increasing EC/herbicide ratios. Distribution of alachlor applied as MEFs at different depths in the soil was higher in the soil surface (66.3-81.3% of herbicide applied at the first 12 cm). In contrast, the residues from CF along the complete soil column were only 20.4%. From the results of bioassays, MEFs showed a higher efficacy than CF at 30 days after the treatment. The use of ME formulations could provide an advantage in minimizing the risk of groundwater contamination by alachlor and reducing the application rates, as a result of maintaining the desired concentration of the herbicide in the top soil layer, obtaining longer periods of weed control.  相似文献   

Mapping Co, a gene controlling the columnar phenotype of apple, with molecular markers   总被引：1，自引：0，他引：1  

Yi-Ke Tian  Cai-Hong Wang  Ji-Shu Zhang  Celia James  Hong-Yi Dai 《Euphytica》2005,145(1-2):181-188

The columnar phenotype is a very valuable genetic resource for apple breeding because of its compact growth form determined by the dominant gene Co. Using bulked segregant analysis combined with several DNA molecular marker techniques to screen the F₁ progeny of Spur Fuji × Telamon (heterozygous for Co), 9 new DNA markers (6 RAPD, 1 AFLP and 2 SSRs) linked to the Co gene were identified. A total of 500 10-mer random primers, 56 pairs of selective AFLP primers and 8 SSR primer pairs were screened. One RAPD marker S1142₆₈₂, and the AFLP marker, E-ACT/M-CTA₃₄₆, were converted into SCAR markers designated SCAR₆₈₂ and SCAR₂₁₆, respectively. These markers will enable early selection in progenies where Co is difficult to identify. The Co gene was located between the SSR markers CH03d11 and COL on linkage group 10 of the apple genetic linkage map. Finally, a local genetic map of the region around the Co gene was constructed by linkage analysis of the nine new markers and three markers developed earlier.  相似文献   

Retention of copper by a calcareous soil and its textural fractions: influence of amendment with two agroindustrial residues     

P. Rodriguez-Rubio  E. Morillo  L. Madrid  T. Undabeytia  & C. Maqueda 《European Journal of Soil Science》2003,54(2):401-409

Metal availability in soils is strongly related with sorption processes and the possible association of the metal ions with a particular particle-size fraction. Therefore, studies of metal retention by a soil will be aided if retention by different size fractions is also studied. Sorption of copper on a calcareous soil and its textural fractions was studied in batch assays. The soil was amended over 3 years with two agroindustrial residues, a composted olive mill sludge and vinasse. Sorption of Cu on the calcareous soil was very large (110 mmol kg⁻¹) and was enhanced by both amendments. Metal retention by the clay fraction of the unamended soil was less than that of the whole soil, but increased dramatically after amendment with olive mill sludge. This was caused by the larger calcite content in this fraction as well as the increase in organic matter content. The amount of Cu sorbed was very large in the silt fraction, again because of the carbonate content of this fraction (300–460 g kg⁻¹). Copper sorption decreased dramatically after removal of carbonate. Copper retention tended to be enhanced by organic amendments. This was particularly evident in the silt fraction, as a consequence of the organic matter accumulation in this fraction.
Copper sorption on the calcareous soil and its silt fractions (unamended and amended) was irreversible. By contrast, desorption was measurable from all the carbonate-free samples (both whole soil and textural fractions), although in all cases a large hysteresis was observed. We conclude that carbonate was the main component responsible for the lack of reversibility.  相似文献   

Determination of potential migrants in polycarbonate containers used for microwave ovens by high-performance liquid chromatography with ultraviolet and fluorescence detection   总被引：3，自引：0，他引：3  

Nerín C  Fernández C  Domeño C  Salafranca J 《Journal of agricultural and food chemistry》2003,51(19):5647-5653

The determination of several compounds present in a commercial polycarbonate container intended to be used in microwave ovens which could be considered as potential migrants has been carried out by reversed-phase high-performance liquid chromatography (HPLC) with both ultraviolet (UV) and fluorescence detectors. Total dissolution with dichloromethane and polymer reprecipitation with methanol have been used to evaluate 100% potential migration as the worst case. The extract consisted of a complex mixture containing monomers, oligomers, UV stabilizers, antioxidants, degradation products, and other additives. Phenol, Bisphenol A, 2,4-di-tert-butylphenol, Cyasorb UV5411, bis(2-ethylhexylphthalate), Irganox 1076, and Irgafos 168 were identified by both retention times and fluorescence-to-UV ratios. Additional confirmation was achieved by HPLC with diode array detection and gas chromatography-mass spectrometry. Recovery percentages were in the range of 73.8-94.4%, the lowest one being for the antioxidant Irgafos 168 due to its transformation into the phosphate form and 2,4-di-tert-butylphenol. The concentrations of the studied analytes present in the polycarbonate container ranged between 0.9 and 240 microg.g(-)(1). The total dissolution conditions that may affect the final concentration of analytes, mainly Bisphenol A, are discussed.  相似文献   

Mercury accumulation in transplanted moss and lichens at high elevation sites in Quebec     

Celia A. Evans  Tom C. Hutchinson 《Water, air, and soil pollution》1996,90(3-4):475-488

Mercury deposition was monitored at two mountain sites in Quebec using transplanted lichens and moss. The terricolous lichen species Cladina rangiferina, the epiphytic lichen species Hypogymnia physodes, and the feather moss Pleurozium schreberi were transplanted from a northern Ontario boreal site to the bases and summits of Roundtop Mountain and Mt. Tremblant in southern Quebec. After 12 months, transplants of C. rangiferina sited at the base and summit of Roundtop mountain and the summit of Mt. Tremblant showed a significant increase in mercury concentration over controls (p < 0.05). The largest difference occurred at the summit of Roundtop mountain where mercury concentration was 81.4 ± 10.9 ppb as compared to 45.6 + 10.6 ppb at the control site. No significant increases in mercury concentration in P. schreberi were seen after 12 months at any site althought trends of increase were apparent. After 20 months, further significant increases in Hg content were observed in both the terricolous lichen and the feather moss at both the Roundtop Mountain base and summit sites. A significant increase in Hg content of P. schreberi was also noted at the Mt. Tremblant summit site. Over the length of the study the greatest mercury concentration increases were observed in the feather moss at the Roundtop Mountain summit site (with a 248.3 ± 30.0 ppb mercury concentration as compared to 108.3 ± 30.0 ppb in controls). No significant change in mercury concentration in the epiphyte H. physodes was found during the study. These data indicate that mercury deposition is occurring, especially to higher elevation sites. While mercury inputs at the summits may be increased by the effects of fog, increases in mercury at the base sites cannot be accounted for the same way, but may represent the importance of dry deposition processes.  相似文献   

Androgen and oestrogen receptors in the growing antlers velvet of adult and yearling pampas deer (Ozotoceros bezoarticus) males     

Alejandro Bielli  Aline Freitas-de-Melo  Patricia Genovese  Matías Villagrán  Celia Tasende  Rodolfo Ungerfeld 《Anatomia, histologia, embryologia》2021,50(6):947-955

To determine the presence, quantity and distribution of androgen (AR) and oestrogen receptors (ER) in the antler velvet (AV), samples were collected from adult and yearling pampas deer males, as well as skin from the ventrolateral abdominal area (ASK). Samples were analysed with ligand-binding assays for AR and ER activity and processed for AR and ERβ immunohistochemistry. There was more content of AR in adults than in yearling males (p = 0.02), as well as a category and type of tissue interaction (p = 0.03). There was more ER content in adults than in yearling males (p = 0.005) and in the AV than in the skin (p = 0.0001). The AR-positive score (PS) was greater in AV than in ASK in the surface stroma (p = 0.0007). In the intermediate epidermis, the AR PS was greater in adults than in yearling males (p = 0.04) and in the ASK than in the AV (p < 0.0001). There was a male category and type of tissue interaction for AR PS in the sebaceous glands (p = 0.014). The ERβ PS in the surface stroma was greater in ASK than in AV (p = 0.004) and tended to be greater in yearling than in adult males (p = 0.093). The ERβ PS in the intermediate epithelium and the sebaceous glands was greater in adults than in yearlings (p = 0.004 and p = 0.007, respectively). In conclusion, we reported for the first time the presence of AR and ER in the velvet skin of growing antlers in pampas deer males. Therefore, the velvet skin is sensitive to both androgens and oestrogens. Furthermore, the greater content of oestrogen receptors in the velvet of adult males suggests that adults are more sensitive to this hormone than yearlings, and thus, oestrogens have greater importance in velvet activity regulation in adult males.  相似文献   

Exercise-associated rhythm disturbances in poorly performing Thoroughbreds: risk factors and association with racing performance     

Celia M. Marr  Samantha Franklin  Georgie Garrod  Claire Wylie  Lewis Smith  Jo Dukes-McEwan  Jan Bright  Kate Allen 《Equine veterinary journal》2021,53(4):656-669

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