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1.
J Environ Manage ; 305: 114407, 2022 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-34974218

RESUMEN

In recent years, some countries have replaced single-use plastic bags with bags manufactured from compostable plastic film that can be used for collecting food wastes and composted together with the waste. Because industrial compost contains undeteriorated fragments of these bags, application to field soil is a potential source of small-sized residues from these bags. This study was undertaken to examine deterioration of these compostable film microplastics (CFMPs) in field soil at three different localities in Italy. Deterioration of CFMPs did not exceed 5.7% surface area reduction during the 12-month experimental period in two sites located in Northern Italy. More deterioration was observed in the Southern site, with 7.2% surface area reduction. Deterioration was significantly increased when fields were amended with industrial compost (up to 9.6%), but not with home compost. Up to 92.9% of the recovered CFMPs were associated with the soil fungus Aspergillus flavus, with 20.1%-71.2% aflatoxin-producing isolates. Application of industrial compost resulted in a significant increase in the percentage of CFMPs associated with A. flavus. This observation provides an argument for government regulation of accumulation of CFMPs and elevation of hazardous fungi levels in agricultural soils that receive industrial compost.


Asunto(s)
Compostaje , Suelo , Aspergillus flavus , Microplásticos , Plásticos
2.
Plants (Basel) ; 12(2)2023 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-36679106

RESUMEN

Charcoal rot, caused by Macrophomina phaseolina, is a major soybean disease resulting in significant yield loss and poor seed quality. Currently, no resistant soybean cultivar is available in the market and resistance mechanisms to charcoal rot are unknown, although the disease is believed to infect plants from infected soil through the roots by unknown toxin-mediated mechanisms. The objective of this research was to investigate the association between seed sugars (sucrose, raffinose, stachyose, glucose, and fructose) and their role as biomarkers in the soybean defense mechanism in the moderately resistant (MR) and susceptible (S) genotypes to charcoal rot. Seven MR and six S genotypes were grown under irrigated (IR) and non-irrigated (NIR) conditions. A two-year field experiment was conducted in 2012 and 2013 at Jackson, TN, USA. The main findings in this research were that MR genotypes generally had the ability to maintain higher seed levels of sucrose, glucose, and fructose than did S genotypes. Conversely, susceptible genotypes showed a higher level of stachyose and lower levels of sucrose, glucose, and fructose. This was observed in 6 out of 7 MR genotypes and in 4 out of 6 S genotypes in 2012; and in 5 out of 7 MR genotypes and in 5 out of 6 S genotypes in 2013. The response of S genotypes with higher levels of stachyose and lower sucrose, glucose, and fructose, compared with those of MR genotypes, may indicate the possible role of these sugars in a defense mechanism against charcoal rot. It also indicates that nutrient pathways in MR genotypes allowed for a higher influx of nutritious sugars (sucrose, glucose, and fructose) than did S genotypes, suggesting these sugars as potential biomarkers for selecting MR soybean plants after harvest. This research provides new knowledge on seed sugars and helps in understanding the impact of charcoal rot on seed sugars in moderately resistant and susceptible genotypes.

3.
Plants (Basel) ; 10(9)2021 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-34579334

RESUMEN

Charcoal rot is a major disease of soybean (Glycine max) caused by Macrophomina phaseolina and results in significant loss in yield and seed quality. The effects of charcoal rot on seed composition (seed protein, oil, and fatty acids), a component of seed quality, is not well understood. Therefore, the objective of this research was to investigate the impact of charcoal rot on seed protein, oil, and fatty acids in different soybean genotypes differing in their charcoal rot susceptibility under irrigated and non-irrigated conditions. Two field experiments were conducted in 2012 and 2013 in Jackson, TN, USA. Thirteen genotypes differing in charcoal rot resistance (moderately resistant and susceptible) were evaluated. Under non-irrigated conditions, moderately resistant genotypes showed either no change or increased protein and oleic acid but had lower linolenic acid. Under non-irrigated conditions, most of the susceptible genotypes showed lower protein and linolenic acid but higher oleic acid. Most of the moderately resistant genotypes had higher protein than susceptible genotypes under irrigated and non-irrigated conditions but lower oil than susceptible genotypes. The different responses among genotypes for protein, oil, oleic acid, and linolenic acid observed in each year may be due to both genotype tolerance to drought and environmental conditions, especially heat differences in each year (2012 was warmer than 2013). This research showed that the increases in protein and oleic acid and the decrease in linolenic acid may be a possible physiological mechanism underlying the plant's responses to the charcoal rot infection. This research further helps scientists understand the impact of irrigated and non-irrigated conditions on seed nutrition changes, using resistant and susceptible genotypes.

4.
Waste Manag ; 113: 312-318, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32570156

RESUMEN

An increasing number of states and municipalities are choosing to reduce plastic litter by replacing plastic items, particularly single-use ones, with same-use products manufactured from compostable plastics. This study investigated the formation and persistence of compostable film microplastic particles (CFMPs) from ultra-thin compostable carrier bags in soil under laboratory conditions, and the potential impact of CFMPs on Aspergillus flavus populations in the soil. During a 12-month incubation period, compostable film samples in soils with small, medium or large populations of indigenous A. flavus, underwent 5.9, 9.8, and 17.1% reduction in total surface area, respectively. Despite the low levels of deterioration, the number of CFMPs released increased steadily over the incubation period, particularly fragments with size < 0.05 mm. Up to 88.4% of the released fragments had associated A. flavus and up to 68% of isolates from CFMPs produced aflatoxins. A. flavus levels associated with CFMPs increased rapidly during the initial part of the 12-month incubation period, whereas the percent aflatoxigenicity continued to increase even after A. flavus density leveled off later. During 12 months incubation, A. flavus DNA amounts recovered from CFMPs increased in soils with all levels of indigenous A. flavus, with the largest increases (119.1%) occurring in soil containing the lowest indigenous A. flavus. These results suggest that burying compostable film in soil, or application of compost containing CFMPs, may reduce soil quality and increase risk of adverse impacts from elevated aflatoxigenic A. flavus populations in soil.


Asunto(s)
Aspergillus flavus , Plásticos Biodegradables , Microplásticos , Suelo , Microbiología del Suelo
5.
J Econ Entomol ; 112(2): 549-557, 2019 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-30561663

RESUMEN

Two isolates of Beauveria bassiana (Balsamo) Vuillemin, including the commercial strain GHA and the Mississippi Delta native NI8 strain, and two emulsifiers, Tween-80 and a starch-based sprayable bioplastic, were evaluated in the laboratory and field for pathogenicity and infectivity against the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae). The effect on fruit damage based on within-season cotton plant mapping was also examined. The highest mortality 10 d after treatment was found with insects caged on cotton terminals sprayed with NI8 + Tween-80, followed by those exposed to NI8 + bioplastic. Similarly, sporulation was shown to be higher in NI8 + Tween-80 than in other treatments. Plots sprayed with B. bassiana showed at least a twofold decrease in tarnished plant bug adults 3 d after treatment compared with control plots. Little to no variation was observed in tarnished plant bug nymph populations between treated and untreated plots. Within-season plant mapping provided clear evidence of damage to cotton caused by tarnished plant bug. The highest percentage retention of all first position fruiting structures was observed in plots treated with NI8 + Tween-80 (93.41 ± 1.51) followed by NI8 + bioplastic (90.25 ± 1.52). Both treatments were significantly different when compared with GHA + Tween-80 (82.89 ± 2.26) and GHA + bioplastic (70.48 ± 3.19), and both GHA formulations did not differ from the control (63.61 ± 2.96). Overall, these results indicated that B. bassiana application resulted in >50% mortality of tarnished plant bug regardless of the isolates by direct spray or by contact. However, the superior performance of the Mississippi Delta native NI8 strain was observed in all treatment applications and evaluation times.


Asunto(s)
Beauveria , Heterópteros , Hypocreales , Animales , Mississippi , Esporas Fúngicas
6.
Toxins (Basel) ; 11(11)2019 11 06.
Artículo en Inglés | MEDLINE | ID: mdl-31698804

RESUMEN

Charcoal rot disease, caused by the fungus Macrophomina phaseolina, results in major economic losses in soybean production in southern USA. M. phaseolina has been proposed to use the toxin (-)-botryodiplodin in its root infection mechanism to create a necrotic zone in root tissue through which fungal hyphae can readily enter the plant. The majority (51.4%) of M. phaseolina isolates from plants with charcoal rot disease produced a wide range of (-)-botryodiplodin concentrations in a culture medium (0.14-6.11 µg/mL), 37.8% produced traces below the limit of quantification (0.01 µg/mL), and 10.8% produced no detectable (-)-botryodiplodin. Some culture media with traces or no (-)-botryodiplodin were nevertheless strongly phytotoxic in soybean leaf disc cultures, consistent with the production of another unidentified toxin(s). Widely ranging (-)-botryodiplodin levels (traces to 3.14 µg/g) were also observed in the roots, but not in the aerial parts, of soybean plants naturally infected with charcoal rot disease. This is the first report of (-)-botryodiplodin in plant tissues naturally infected with charcoal rot disease. No phaseolinone was detected in M. phaseolina culture media or naturally infected soybean tissues. These results are consistent with (-)-botryodiplodin playing a role in the pathology of some, but not all, M. phaseolina isolates from soybeans with charcoal rot disease in southern USA.


Asunto(s)
Ascomicetos/crecimiento & desarrollo , Furanos/metabolismo , Glycine max/microbiología , Micotoxinas/metabolismo , Enfermedades de las Plantas/microbiología , Ascomicetos/metabolismo , Raíces de Plantas/microbiología , Glycine max/metabolismo
7.
Chemosphere ; 226: 645-650, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30959449

RESUMEN

Encapsulating fungicides and/or insecticides in film-coatings applied to agronomic seeds has become a widely accepted method for enhancing seed germination and overall seedling health by protecting against many diseases and early-season insect pests. Despite advancements in seed film-coating technologies, abrasion of the seed coating can occur during handling and mechanical planting operations, resulting in variable amounts of detached fragments entering the soil. The present study investigated the degradation in soil of these plastic-like, small-sized fragments, referred to here as microplastic coating fragments. Degradation of microplastic coating fragments in soil was found to be highly variable. The lowest degradation rate (≤48 days) was observed in fragments detached from seeds coated with a commercial polymer mixture, while fragments from a biodegradable plastic formulation degraded completely within 32 days. When spores of the plant growth-promoting bacterium, Bacillus subtilis, were incorporated into the bioplastic, degradation was even more rapid (≤24 days). The fragment degradation rate was unaffected by incorporating two commonly used neonicotinoid insecticides, imidacloprid or thiacloprid, into either coating formulations, but insecticide dissipation rates in soil were more rapid when added associated with seed coating fragments than when spiked in directly. Half-lives of these two insecticides were reduced by up to 27% in fragments from bioplastic-coated seeds. These results are consistent with variable and not easily predicted soil degradation rates for seed coating fragments, with enhanced dissipation of coating-entrapped pesticides and with a higher degradation rate for biodegradable seed coating incorporating selected microbial strains.


Asunto(s)
Fungicidas Industriales/metabolismo , Insecticidas/metabolismo , Plaguicidas/metabolismo , Plásticos/metabolismo , Semillas/química , Contaminantes del Suelo/metabolismo , Suelo/química , Bacillus subtilis/metabolismo , Insecticidas/análisis , Neonicotinoides/metabolismo , Nitrocompuestos/metabolismo , Plantones/metabolismo , Contaminantes del Suelo/análisis , Tiazinas/metabolismo
8.
Environ Health Perspect ; 116(11): 1563-7, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19057712

RESUMEN

On 3 October 2007, 40 participants with diverse expertise attended the workshop Tamiflu and the Environment: Implications of Use under Pandemic Conditions to assess the potential human health impact and environmental hazards associated with use of Tamiflu during an influenza pandemic. Based on the identification and risk-ranking of knowledge gaps, the consensus was that oseltamivir ethylester-phosphate (OE-P) and oseltamivir carboxylate (OC) were unlikely to pose an ecotoxicologic hazard to freshwater organisms. OC in river water might hasten the generation of OC-resistance in wildfowl, but this possibility seems less likely than the potential disruption that could be posed by OC and other pharmaceuticals to the operation of sewage treatment plants. The work-group members agreed on the following research priorities: a) available data on the ecotoxicology of OE-P and OC should be published; b) risk should be assessed for OC-contaminated river water generating OC-resistant viruses in wildfowl; c) sewage treatment plant functioning due to microbial inhibition by neuraminidase inhibitors and other antimicrobials used during a pandemic should be investigated; and d) realistic worst-case exposure scenarios should be developed. Additional modeling would be useful to identify localized areas within river catchments that might be prone to high pharmaceutical concentrations in sewage treatment plant effluent. Ongoing seasonal use of Tamiflu in Japan offers opportunities for researchers to assess how much OC enters and persists in the aquatic environment.


Asunto(s)
Gripe Humana/tratamiento farmacológico , Oseltamivir/uso terapéutico , Humanos , Medición de Riesgo
9.
J Agric Food Chem ; 56(3): 1025-8, 2008 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-18181567

RESUMEN

Although a number of studies have been done describing the fate of Bacillus thuringiensis insecticidal endotoxins in soil, there is conflicting information on the persistence of this class of insecticidal toxins. This is partly due to methodological limitations in many of the previous studies. In the experiments reported here, 14C-labeled B. thuringiensis Cry1Ac endotoxin was used to study its mineralization in soil incubated under controlled conditions. Fifty-nine percent of the radiolabeled Cry1Ac was recovered as 14CO2 at the end of the 20 day incubation period. The addition of 4.5% corn residues stimulated mineralization of [14C]Cry1Ac toxin, and mineralization of glucose was 3.6 times faster than that of the Cry1Ac toxin, indicating that the soil was microbiologically and metabolically active. Because only low mineralization (approximately 6%) of the radiolabeled toxin was observed in autoclaved soil, the current findings indicate that microbial processes play a major role in the dissipation of the Cry1Ac endotoxin in soil. The results of this study suggest that there may be limited risk of the bioaccumulation of Cry1Ac in soil due to the eventual release of this insecticidal toxin by Bt-protected crops.


Asunto(s)
Proteínas Bacterianas/metabolismo , Toxinas Bacterianas/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Minerales/metabolismo , Microbiología del Suelo , Suelo/análisis , Toxinas de Bacillus thuringiensis , Oxidación-Reducción , Plantas Modificadas Genéticamente/metabolismo
10.
J Environ Qual ; 37(3): 848-57, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18453406

RESUMEN

Soil bacteria have developed novel metabolic abilities resulting in enhanced atrazine degradation. Consequently, there is a need to evaluate the effects of enhanced degradation on parameters used to model atrazine fate and transport. The objectives of this study were (i) to screen Colorado (CO) and Mississippi (MS) atrazine-adapted and non-adapted soil for genes that code for enzymes able to rapidly catabolize atrazine and (ii) to compare atrazine persistence, Q(10), beta, and metabolite profiles between adapted and non-adapted soils. The atzABC and/or trzN genes were detected only in adapted soil. Atrazine's average half-life in adapted soil was 10-fold lower than that of the non-adapted soil and 18-fold lower than the USEPA estimate of 3 to 4 mo. Q(10) was greater in adapted soil. No difference in beta was observed between soils. The accumulation and persistence of mono-N-dealkylated metabolites was lower in adapted soil; conversely, under suboptimal moisture levels in CO adapted soil, hydroxyatrazine concentrations exceeded 30% of the parent compounds' initial mass. Results indicate that (i) enhanced atrazine degradation and atzABC and/or trzN genes are likely widespread across the Western and Southern corn-growing regions of the USA; (ii) persistence of atrazine and its mono-N-dealkylated metabolites is significantly reduced in adapted soil; (iii) hydroxyatrazine can be a major degradation product in adapted soil; and (iv) fate, transport, and risk assessment models that assume historic atrazine degradation pathways and persistence estimates will likely overpredict the compounds' transport potential in adapted soil.


Asunto(s)
Atrazina/química , Contaminantes del Suelo/química , Secuencia de Bases , Cromatografía Líquida de Alta Presión , Colorado , Cartilla de ADN , Cromatografía de Gases y Espectrometría de Masas , Mississippi
11.
J Agric Food Chem ; 55(7): 2677-82, 2007 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-17348682

RESUMEN

Veterinary antimicrobial agents have been detected in a number of environmental samples, including agricultural soils. In this study, we investigated the persistence and sorption of the sulfonamides sulfamethazine (SMZ) and sulfachloropyridine (SCP) in soil and their potential effects on soil microorganisms. The sulfonamides dissipated more rapidly from the silt loam soil as compared to the sandy soil. Average half-lives of SMZ and SPC among the two soils were 18.6 and 21.3 days, respectively. The presence of liquid swine slurry (5% v/w) decreased sulfonamide persistence in the silt loam soil. The lower persistence of the antimicrobials in liquid swine slurry-amended soil was likely due to higher microbial activity, as compared to unamended soil, and/or to the greater bioavailability of the sulfonamides to degrading microorganisms, as estimated by sorption isotherms. Concentrations of SMZ and SPC up to 100 microg g-1 had no effect on antimicrobial degradation rates and soil microorganisms. These studies suggest that higher sulfonamide concentrations would be necessary to affect the main processes controlling their environmental fates in soil, but at the concentrations normally found in the environment, there would be little or no effects.


Asunto(s)
Antiinfecciosos/análisis , Ambiente , Suelo/análisis , Sulfonamidas/análisis , Adsorción , Antiinfecciosos/química , Sulfametazina/análisis , Sulfonamidas/química
12.
J Agric Food Chem ; 65(33): 7081-7087, 2017 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-28420231

RESUMEN

Aflatoxin contamination has a major economic impact on crop production in the southern United States. Reduction of aflatoxin contamination in harvested crops has been achieved by applying nonaflatoxigenic biocontrol Aspergillus flavus strains that can out-compete wild aflatoxigenic A. flavus, reducing their numbers at the site of application. Currently, the standard method for applying biocontrol A. flavus strains to soil is using a nutrient-supplying carrier (e.g., pearled barley for Afla-Guard). Granules of Bioplastic (partially acetylated corn starch) have been investigated as an alternative nutritive carrier for biocontrol agents. Bioplastic granules have also been used to prepare a sprayable biocontrol formulation that gives effective reduction of aflatoxin contamination in harvested corn kernels with application of much smaller amounts to leaves later in the growing season. The ultimate goal of biocontrol research is to produce biocontrol systems that can be applied to crops only when long-range weather forecasting indicates they will be needed.


Asunto(s)
Aflatoxinas/análisis , Inoculantes Agrícolas/fisiología , Aspergillus flavus/fisiología , Productos Agrícolas/microbiología , Contaminación de Alimentos/prevención & control , Hongos/fisiología , Enfermedades de las Plantas/prevención & control , Aflatoxinas/metabolismo , Inoculantes Agrícolas/química , Antibiosis , Aspergillus flavus/química , Productos Agrícolas/química , Enfermedades de las Plantas/microbiología
13.
J Agric Food Chem ; 54(1): 164-9, 2006 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-16390194

RESUMEN

The impact of transgenic plants containing Bacillus thuringiensis (Bt) toxin on soil processes has received recent attention. In these studies, we examined the influence of the lepidopterean Bt Cry1Ac toxin on mineralization and bioavailability of the herbicide glyphosate in two different soils. The addition of 0.25-1.0 microg g(-1) soil of purified Cry1Ac toxin did not significantly affect glyphosate mineralization and sorption in either a sandy loam or a sandy soil. In contrast, extractable glyphosate decreased over the 28 day incubation period in both soils. Our findings suggest that the reduction in the bioavailability of glyphosate was not influenced by the presence of Cry1Ac toxin but rather the results of aging or sorption processes. Results from this investigation suggest that the presence of moderate concentrations of Bt-derived Cry1Ac toxin would have no appreciable impact on processes controlling the fate of glyphosate in soils.


Asunto(s)
Proteínas Bacterianas/farmacología , Toxinas Bacterianas/farmacología , Endotoxinas/farmacología , Glicina/análogos & derivados , Minerales/análisis , Suelo/análisis , Adsorción , Toxinas de Bacillus thuringiensis , Glicina/química , Glicina/metabolismo , Proteínas Hemolisinas , Microbiología del Suelo , Glifosato
14.
Chemosphere ; 63(9): 1539-45, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16289696

RESUMEN

Recent monitoring investigations have shown that antimicrobial agents used in veterinary medicine can cause non-point source contamination of soils through manure spreading. In the present study, the effect of the antimicrobial agent sulfamethazine (sulfadimidine) on degradation and sorption of the herbicide metolachlor in a sandy loam soil was studied. In soil samples treated with sulfamethazine at two concentrations (15 and 150 microg kg(-1) soil), metolachlor persistence was not different than of that observed in untreated samples. These results were supported by the absence of effects of both sulfamethazine concentration levels on the size of the culturable soil bacteria population. Equilibrating soil samples with metolachlor solutions containing equivalent sulfamethazine concentrations did not lead to any significant effects on metolachlor sorption, suggesting that, under the conditions of the present experiment, sulfamethazine did not affect metolachlor bioavailability in soil. This laboratory investigation showed that concentrations of sulfamethazine in the microg kg(-1) range did not cause significant effects on metolachlor degradation and sorption thus not affecting the main processes ruling its environmental fate in soil.


Asunto(s)
Acetamidas/metabolismo , Antiinfecciosos/farmacología , Contaminantes del Suelo/metabolismo , Suelo , Sulfametazina/farmacología , Adsorción , Antiinfecciosos/farmacocinética , Disponibilidad Biológica , Estiércol , Sulfametazina/farmacocinética
15.
Pest Manag Sci ; 72(8): 1521-8, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26518170

RESUMEN

BACKGROUND: Applying non-aflatoxin-producing Aspergillus flavus isolates to the soil has been shown to be effective in reducing aflatoxin levels in harvested crops, including peanuts, cotton and corn. The aim of this study was to evaluate the possibility of controlling aflatoxin contamination using a novel sprayable formulation consisting of a partially gelatinized starch-based bioplastic dispersion embedded with spores of biocontrol A. flavus strains, which is applied to the leaf surfaces of corn plants. RESULTS: The formulation was shown to be adherent, resulting in colonization of leaf surfaces with the biocontrol strain of A. flavus, and to reduce aflatoxin contamination of harvested kernels by up to 80% in Northern Italy and by up to 89% in the Mississippi Delta. The percentage of aflatoxin-producing isolates in the soil reservoir under leaf-treated corn was not significantly changed, even when the soil was amended with additional A. flavus as a model of changes to the soil reservoir that occur in no-till agriculture. CONCLUSIONS: This study indicated that it is not necessary to treat the soil reservoir in order to achieve effective biocontrol of aflatoxin contamination in kernel corn. Spraying this novel bioplastic-based formulation to leaves can be an effective alternative in the biocontrol of A. flavus in corn. © 2015 Society of Chemical Industry.


Asunto(s)
Aflatoxinas/análisis , Aspergillus flavus , Control Biológico de Vectores/métodos , Zea mays/microbiología , Contaminación de Alimentos/prevención & control , Italia , Mississippi , Hojas de la Planta/química , Hojas de la Planta/microbiología , Polímeros , Zea mays/química
16.
J Agric Food Chem ; 53(10): 4110-7, 2005 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-15884847

RESUMEN

In modern agricultural systems employing conservation tillage practices, glyphosate is widely used as a preplant burndown herbicide in a wide range of crops. Conservation tillage systems are characterized by a significant presence of crop residues at the soil surface so that glyphosate is applied to a soil matrix rich in poorly decomposed crop residues. Incorporation of corn residues in the range from 0.5 to 4% caused different effects on mineralization and sorption of [14C]glyphosate in sandy and sandy loam soils. More specifically, low levels of incorporated corn residues did not affect or slightly stimulated herbicide mineralization in the sandy and sandy loam soils, respectively. In the sandy soil, incorporation of the highest level of corn residues (4%) caused a decrease in [14C]glyphosate mineralization. [14C]Glyphosate sorption on both soil types was reduced in samples receiving high amounts of incorporated corn residues.


Asunto(s)
Glicina/análogos & derivados , Glicina/análisis , Glicina/química , Herbicidas/química , Minerales/química , Suelo/análisis , Zea mays/química , Adsorción , Radioisótopos de Carbono , Fenómenos Químicos , Química Física , Concentración de Iones de Hidrógeno , Microbiología del Suelo , Glifosato
17.
Pest Manag Sci ; 69(9): 1085-91, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23436551

RESUMEN

BACKGROUND: A novel biocontrol strategy consisting of field application of bioplastic-based granules inoculated with a non-toxigenic Aspergillus flavus L. strain has recently been shown to be effective for reducing aflatoxin contamination in corn. This study focused on other factors that may affect the feasibility of this biocontrol technique, and more specifically the role of the European corn borer (ECB), Ostrinia nubilalis H., in the dispersal and infestation of A. flavus in corn and its impact on crop yield. RESULTS: In spite of the high percentage of corn ears showing larval feeding damage, ECB-bored kernels accounted for only 3 and 4% in 2009 and 2010 respectively. Most of the damaged kernels were localised in the ear tip or immediately below. More precisely, the average incidence of ECB-bored kernels in the upper end of the ear was 32%. However, less than 5% of kernels from the central body of the ear, which includes the majority of kernels, were injured by ECB. CONCLUSIONS: Although ECB larvae showed a high tolerance to aflatoxin B1 and thus had the potential to serve as vectors of the mould, fungal infection of kernels was poorly associated with insect damage. ECB infestation resulted in grain yield losses not exceeding 2.5%.


Asunto(s)
Aspergillus flavus/fisiología , Mariposas Nocturnas/crecimiento & desarrollo , Mariposas Nocturnas/microbiología , Control Biológico de Vectores/métodos , Enfermedades de las Plantas/parasitología , Zea mays/parasitología , Animales , Enfermedades de las Plantas/prevención & control
18.
J Agric Food Chem ; 61(48): 11759-70, 2013 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-23750911

RESUMEN

Mycotoxin contamination levels in maize kernels are controlled by a complex set of factors including insect pressure, fungal inoculum potential, and environmental conditions that are difficult to predict. Methods are becoming available to control mycotoxin-producing fungi in preharvest crops, including Bt expression, biocontrol, and host plant resistance. Initial reports in the United States and other countries have associated Bt expression with reduced fumonisin, deoxynivalenol, and zearalenone contamination and, to a lesser extent, reduced aflatoxin contamination in harvested maize kernels. However, subsequent field results have been inconsistent, confirming that fumonisin contamination can be reduced by Bt expression, but the effect on aflatoxin is, at present, inconclusive. New maize hybrids have been introduced with increased spectra of insect control and higher levels of Bt expression that may provide important tools for mycotoxin reduction and increased yield due to reduced insect feeding, particularly if used together with biocontrol and host plant resistance.


Asunto(s)
Proteínas Bacterianas/genética , Endotoxinas/genética , Contaminación de Alimentos/análisis , Proteínas Hemolisinas/genética , Micotoxinas/análisis , Plantas Modificadas Genéticamente/química , Zea mays/química , Toxinas de Bacillus thuringiensis , Proteínas Bacterianas/metabolismo , Endotoxinas/metabolismo , Inocuidad de los Alimentos , Proteínas Hemolisinas/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Plantas Modificadas Genéticamente/microbiología , Estados Unidos , Zea mays/genética , Zea mays/metabolismo , Zea mays/microbiología
19.
Bioresour Technol ; 120: 180-6, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22797083

RESUMEN

In this series of laboratory experiments, the feasibility of using moving bed biofilm carriers (MBBC) manufactured from existing bioplastic-based products for the removal of bisphenol A, oseltamivir, and atrazine from wastewater was evaluated. After 10-d incubation, cumulative evolution of (14)CO(2) from control (no MBBC) wastewater spiked with (14)C-labeled bisphenol A, oseltamivir or atrazine, accounted for approximately 18%, 7% and 3.5% of the total added radioactivity, respectively. When wastewater samples were incubated with freely moving carriers, greater removal of the three chemicals was observed. More specifically, cumulative (14)CO(2) evolution of the three xenobiotics increased of 34%, 49%, and 66%, with respect to the control, respectively. Removal efficiency of MBBC was significantly increased by inoculating these bioplastic carriers with bioremediation bacterial strains. Results from this study suggest that the concept behind the moving bed biofilm reactor technology can also be extended to biodegradable carriers inoculated with bioremediation microorganisms.


Asunto(s)
Biopelículas , Plásticos/química , Aguas Residuales/química , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/instrumentación , Purificación del Agua/métodos , Bacterias/genética , Adhesión Bacteriana , Biodegradación Ambiental , Minerales/química , Movimiento , Reacción en Cadena de la Polimerasa , Contaminantes Químicos del Agua/química
20.
Chemosphere ; 89(2): 136-43, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22717162

RESUMEN

Increasing environmental concerns and the introduction of technologies based on renewable resources have stimulated the replacement of persistent petroleum-derived plastics with biodegradable plastics from biopolymers. As a consequence, a variety of products are currently manufactured from bioplastic, including carrier bags. This series of studies investigated the deterioration of carrier bags made with Mater-Bi (MB), a starch-based bioplastic, in soil, compost and two aquatic ecosystems, a littoral marsh and seawater. Results from the laboratory study indicated that bioplastic carrier bags were rapidly deteriorated in soil and compost. After three months of incubation, weight loss of specimens was of 37% and 43% in soil and compost, respectively. Conversely, little deterioration was observed in specimens buried in soil under field conditions or exposed to water of a littoral marsh and of the Adriatic Sea. These findings were consistent with the greater number of bacteria and especially fungi capable of degrading MB that were recovered from soil and compost with respect to the two aquatic ecosystems. Considering that a variety of microbial isolates are capable of using MB as a source of carbon, a new alternative to recycle these MB-based carrier bags was explored. More specifically, starchy residues from bags were fermented by the fungus Rhizopus oryzae to produce up to 35 mg of lactic acid per g of bag residues.


Asunto(s)
Ambiente , Plásticos/química , Plásticos/metabolismo , Reciclaje/métodos , Bacterias/metabolismo , Biodegradación Ambiental , Contaminación Ambiental/prevención & control , Hongos/metabolismo , Ácido Láctico/biosíntesis , Océanos y Mares , Suelo/química , Almidón/química , Humedales
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