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1.
Science ; 372(6537): 81-84, 2021 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-33795455

RESUMEN

Pesticide impacts are usually discussed in the context of applied amounts while disregarding the large but environmentally relevant variations in substance-specific toxicity. Here, we systemically interpret changes in the use of 381 pesticides over 25 years by considering 1591 substance-specific acute toxicity threshold values for eight nontarget species groups. We find that the toxicity of applied insecticides to aquatic invertebrates and pollinators has increased considerably-in sharp contrast to the applied amount-and that this increase has been driven by highly toxic pyrethroids and neonicotinoids, respectively. We also report increasing applied toxicity to aquatic invertebrates and pollinators in genetically modified (GM) corn and to terrestrial plants in herbicide-tolerant soybeans since approximately 2010. Our results challenge the claims of a decrease in the environmental impacts of pesticide use.


Asunto(s)
Organismos Acuáticos/efectos de los fármacos , Productos Agrícolas , Invertebrados/efectos de los fármacos , Plaguicidas/toxicidad , Plantas Modificadas Genéticamente , Plantas/efectos de los fármacos , Animales , Herbicidas/toxicidad , Insecticidas/toxicidad , Neonicotinoides/toxicidad , Piretrinas/toxicidad , Soja , Zea mays
2.
Braz J Biol ; 82: e238763, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33825760

RESUMEN

We report the discovery that the earwig predator Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae) feed on Puccinia polysora Underw uredospore, the causal agent of Southern Rust of Corn (SRC), which is a primary disease affecting the maize crop in Brazil. We performed experiments in laboratory and greenhouse to test the effect of D. luteipes (1st/2nd and 3rd/4th instars, and adults) fungivory on the P. polysora uredospore concentration. All trials showed a significant reduction of the initial concentration of uredospore. There was a reduction in uredospore concentration with increase in number of D. luteipes feeding on them. We also tested the uredospore consumption by quantifying its percentage in the feces of D. luteipes. Nymphs of the 2nd, 4th instar and adults fed 88%, 85%, and 83.8% of the uredospore, respectively. For nymphs of the 3rd instar, the percentage of uredospore consumption (75.6%) was statistically significant compared with the other groups. In greenhouse experiment, at twenty-eight days after plant inoculation with 9.9 x 104 uredospores, the percentage of uredospore consumption was 81.7%. Our results confirmed the fungivory of D. luteipes on P. polysora uredospore. This is the first report of D. luteipes fungivory, which may play an important role in the biological control of P. polysora in corn.


Asunto(s)
Zea mays , Animales , Brasil , Ninfa
3.
Sci Total Environ ; 772: 145674, 2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-33663956

RESUMEN

Soil serves many important ecological functions and is an integral part of our existence as a society. However, concerns for soil health are growing globally, in part due to the negative impacts of agricultural management on soil resources. The production of perennial bioenergy crops on marginal land in row-crop production systems is one solution that could improve land-use efficiency and address the sustainability of cropland management. Because the relationship between crop management and the environment is complex, more research is needed to evaluate the potential benefits perennial bioenergy crop production has on soil health, as well as other ecosystem services. In this study, shrub willow buffers were strategically integrated into a corn-soybean cropping system with the main objective of reducing nitrate-N leaching from grain crop production while producing biomass for bioenergy. Two buffer systems (defined by landscape positions) were included for comparison, one on marginal land with exposure to nitrate-N leaching from upslope grain (southern plots) and one on fertile soils with less nitrate-N leaching potential (northern plots). Evaluation of soil (chemistry, bulk density, microbial community) and shrub willow vegetation properties (fine roots, leaf litter decomposition, and nutrient uptake dynamics), showed that landscape position plays an important role in (1) the dynamics of soil chemical properties, (2) shrub willow's influence and productivity, and (3) the provision of additional ecosystem services such as reductions in nitrous oxide emissions and nitrate-N leaching. In addition, the combination of crop type and landscape position (N-grain, N-willow, S-grain, and S-willow) influenced the species composition of the soil microbial community, resulting in unique and identifiable communities. These results highlight the potential application of shrub willow buffers for ecosystem service provision and support of ecosystem processes; however, understanding the relationship between the microbial community, crop type, and landscape is important for understanding the sustainability of the design.


Asunto(s)
Microbiota , Salix , Illinois , Suelo , Soja , Zea mays
4.
J Insect Sci ; 21(2)2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33686434

RESUMEN

Brown stink bugs, Euschistus servus, are an important early-season pest of field corn in the southeastern United States. Feeding in the early stages of corn development can lead to a number of growth deformities and deficiencies and, ultimately, a reduction in yield. An observational and two experimentally manipulated trials were conducted in 2017 and 2018 to 1) determine optimal timing for assessing brown stink bug damage, 2) assess the level of damage from which yield compensation can occur, and 3) examine the relationship between brown stink bug density and early-season damage and yield. Fields were identified with infestations of brown stink bugs and a damage rating system for early stages of corn was established. Varying rates of brown stink bug densities were introduced using field cages and damage was assessed throughout the season. The density and duration of stink bug infestations were critical factors for damage potential, with each day of active feeding per plant resulting in a loss of ~14 kg/ha in yield. The level of damage in early stages of corn was categorized into easily identifiable groups, with only the most severe damage leading to a reduction in yield. Moderate and minimal feeding damage did not result in yield loss. This study emphasizes the need for early and frequent scouting of corn to determine the risk of damage and yield loss from brown stink bugs. Results from this study can be used to help develop management programs for brown stink bugs in the early vegetative stages of field corn.


Asunto(s)
Biomasa , Hemípteros , Herbivoria , Zea mays , Animales , Femenino , Control de Insectos , Masculino , Plantones
5.
Ying Yong Sheng Tai Xue Bao ; 32(3): 931-941, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33754559

RESUMEN

To clarify the effects of combined applications of chlorocholine chloride (CCC) and nitrogen fertilizer (CN) on nitrogen metabolism and nitrogen use efficiency of summer maize, we conducted a field experiment in Xinxiang experimental station of Chinese Academy of Agricultural Sciences in 2018 and 2019, with four nitrogen application rates (0, 62.5, 125 and 187.5 kg·hm-2), and two maize varieties of Jingnongke 728 (JNK728) and Zhongdan 909 (ZD909). The results showed that across the two years CN-CCC increased maize yield by 7.7% and 5.0% under the nitrogen application rates of 62.5 kg·hm-2 and 125 kg·hm-2, respectively. CN-CCC increased the contents of nitrate reductase, glutamine synthetase, glutamate synthetase and soluble protein, and finally promoted nitrogen metabolism. Under the low and middle nitrogen application conditions (62.5 kg·hm-2 and 125 kg·hm-2), plant nitrogen content of JNK728 and ZD909 increased by 17.6% and 30.3%, grain nitrogen content increased by 10.3% and 17.4%, nitrogen partial productivity, agronomic efficiency of applied nitrogen, recovery efficiency of applied nitrogen, nitrogen use efficiency increased by 10.0%, 15.7%, 23.3%, 24.8% and 5.7%, 15.0%, 49.9%, 71.7%, respectively. In conclusion, appropriate basic application of CN-CCC could enhance nitrogen metabolism, increase nitrogen use efficiency and grain yield of summer maize. Our results showed that CCC combined basic nitrogen application of 125 kg·hm-2 had the best effect.


Asunto(s)
Fertilizantes , Nitrógeno , Agricultura , China , Clormequat , Nitrógeno/análisis , Suelo , Zea mays
6.
Huan Jing Ke Xue ; 42(3): 1166-1176, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742913

RESUMEN

A total of 86 soil samples, 86 corn kernel samples, 50 tailings samples, and 33 ore rock samples were collected in reclaimed land and surrounding areas of typical vanadium-titanium magnetite tailings located in the Chengde Central Region and analyzed for 14 elements (P, Fe, Cu, Ni, Cd, Cr, Pb, Zn, Hg, Ti, Mn, and Mo) and speciation of heavy metals. This study investigated the bioaccumulation and translocation characteristics of heavy metals in a soil-maize system based on a descriptive statistical analysis, a geological accumulative index, bioconcentration factors, and a redundancy analysis. The results showed that the average accumulation index of surface soil followed an order of P > Cu > Fe2O3 > Cr > Ti > V > Ni > Mn > Cd > Zn > Mo > As > Pb > Hg, while the accumulation level of heavy metals was generally categorized as either no accumulation or moderate accumulation. Compared to China's soil environmental quality standard risk screening values (GB15618-2018), the over-standard rates of Cr and Cu were 2.32% and 1.16%, respectively. The content of Fe, Ti, As, Pb, and Mn in the corn kernels of the tailings and surrounding areas was relatively high, and the content of Mo, Ni, Cu, Zn, Cd, and Cr in the control area was relatively high. The over-standard rates of Ni, Zn, and Cu in the corn kernels were 13.61%, 13.23%, and 5.17% respectively, according to China's national food safety standard limits for contaminants in food (GB 2762-2017). The bioconcentration factors of Fe, Ti, As, Pb, and Mn in the corn kernels of the tailings and the surrounding areas were relatively higher, while the bioconcentration factors of Mo, Ni, Cu, Zn, Cd, and Cr were lower than in control area. The bioactive components of Cd accounted for 50.17%, which was the highest, followed by Ni, Zn, and Cu with average ratios of 13.61%, 13.23%, and 5.17%, respectively. Compared to the control area, the Pb, As and Hg elements in the soil samples of the reclaimed land showed a lower total amount but a higher bioavailability content and soil pH value, while the Cu and Hg elements showed a higher total amount but lower bioavailability content and soil pH value. These differences in total heavy metal concentrations, bioavailability amounts, and soil pH values made the bioconcentration intensity of As and Pb in the tailings reservoir and surrounding area relatively higher. When studying the ecological risk of heavy metal pollution or determining the remediation target value of reclaimed land in a mine tailings reservoir and the soil around the mine area, the bioavailable state limit of heavy metals should be should be taken into account as the evaluation standard.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Bioacumulación , China , Monitoreo del Ambiente , Óxido Ferrosoférrico , Metales Pesados/análisis , Medición de Riesgo , Suelo , Contaminantes del Suelo/análisis , Titanio , Vanadio , Zea mays
7.
Bioresour Technol ; 329: 124919, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33676353

RESUMEN

Links between synergy and microbial community characteristics in co-digestion of food waste (FW), cattle manure (CM) and corn straw (CS) were investigated. Mono-digestion of FW and CS were inhibited by organic acids. Co-digestion of FW with CM achieved greater synergistic rates (18.5% and 22.3%) than CM with CS (14.8% and 12.3%). Synergy resulted from coupling effects of improving nutrient balance, dilution of toxic compounds, higher buffering capacity, detoxification based on co-metabolism, which ultimately reflected in microbial community functions. Although co-digestion of FW with CS exhibited lowest synergistic rates (7.9% and 4.9%), detoxification based on co-metabolism of syntrophic communities of Syntrophomonadaceae with hydrogenotrophic methanogens accelerated system recovery. Digester with the greatest synergy (65% FW + 35% CM) maintained dominant growth of hydrogenotrophic methanogens (68.9%), highest methanogenic community diversity and relative abundance of Methanosarcina (14.6%), which sustained more diverse and switchable methanogenic pathways therefore ensured powerful methanogenic functions and vigorous methanogenic capability.


Asunto(s)
Microbiota , Eliminación de Residuos , Anaerobiosis , Animales , Biocombustibles , Reactores Biológicos , Bovinos , Digestión , Alimentos , Estiércol , Metano , Zea mays
8.
Bioresour Technol ; 329: 124926, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33684841

RESUMEN

Cellulosic ethanol fermentability of ethanologenic strain Zymomonas mobilis is severely inhibited by phenolic aldehydes generated from lignocellulose pretreatment. Here, a 198 days' laboratory adaptive evolution of Z. mobilis 8b in corn stover hydrolysate was conducted to increase its phenolic aldehydes tolerance and ethanol fermentability. The obtained Z. mobilis Z198 demonstrated a significantly improved conversion of the most toxic phenolic aldehyde (vanillin) by 6.3-fold and cellulosic ethanol production by 21.6%. The transcriptional analysis using qRT-PCR revealed that the gene ZMO3_RS07160 encoding SDR family oxidoreductase in Z. mobilis Z198 was significantly up-regulated by 11.7-fold. The overexpression of ZMO3_RS07160 in the parental Z. mobilis increased the ethanol fermentability to that of the adaptively evolved strain Z. mobilis Z198. This study provided a practical method to obtain a robust cellulosic ethanol fermenting strain, and a candidate gene for synthetic biology of biorefinery strains with strong phenolic aldehydes tolerance.


Asunto(s)
Zymomonas , Tolerancia a Medicamentos , Etanol , Fermentación , Zea mays , Zymomonas/genética
9.
Bioresour Technol ; 329: 124907, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33706175

RESUMEN

To further explain effects of pyrolysis temperature on physicochemical properties of corn stalk pellet biochar from a new perspective, various lab physicochemical analysis methods combining microcomputed tomography were used to characterize biochar in this study. The results showed that at pyrolysis temperatures from 300 °C to 800 °C, yield of biochar decreased logarithmically with increasing pyrolysis temperature (T); changes of proximate and elemental compositions all showed significant differences, but the change rules were not consistent; high temperature pyrolysis biochar had high stability, high hardness and was convenient for storage and transportation; the proportions of hydroxyl group and amino group were highest in BC800 and BC600, respectively, contributing to the adsorption and removal of pollutants; BC400 had the best combustion performance; X-ray mean attenuation coefficient (XMAC) showed the following correlations, namely, XMAC = 0.003*ln(T-285.329) + 0.011 (R2 = 0.904) and XMAC = -0.031*(VM/100) + 0.021*(Ash/100) + 0.027 (R2 = 0.915). Above results provide important basic data support for development of corn stalk pellet biochar.


Asunto(s)
Pirólisis , Zea mays , Adsorción , Carbón Orgánico , Temperatura , Microtomografía por Rayos X
10.
Sensors (Basel) ; 21(4)2021 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-33671356

RESUMEN

Phenology is an indicator of crop growth conditions, and is correlated with crop yields. In this study, a phenological approach based on a remote sensing vegetation index was explored to predict the yield in 314 counties within the US Corn Belt, divided into semi-arid and non-semi-arid regions. The Moderate Resolution Imaging Spectroradiometer (MODIS) data product MOD09Q1 was used to calculate the normalized difference vegetation index (NDVI) time series. According to the NDVI time series, we divided the corn growing season into four growth phases, calculated phenological information metrics (duration and rate) for each growth phase, and obtained the maximum correlation NDVI (Max-R2). Duration and rate represent crop growth days and rate, respectively. Max-R2 is the NDVI value with the most significant correlation with corn yield in the NDVI time series. We built three groups of yield regression models, including univariate models using phenological metrics and Max-R2, and multivariate models using phenological metrics, and multivariate models using phenological metrics combined with Max-R2 in the whole, semi-arid, and non-semi-arid regions, respectively, and compared the performance of these models. The results show that most phenological metrics had a statistically significant (p < 0.05) relationship with corn yield (maximum R2 = 0.44). Models established with phenological metrics realized yield prediction before harvest in the three regions with R2 = 0.64, 0.67, and 0.72. Compared with the univariate Max-R2 models, the accuracy of models built with Max-R2 and phenology metrics improved. Thus, the phenology metrics obtained from MODIS-NDVI accurately reflect the corn characteristics and can be used for large-scale yield prediction. Overall, this study showed that phenology metrics derived from remote sensing vegetation indexes could be used as crop yield prediction variables and provide a reference for data organization and yield prediction with physical crop significance.


Asunto(s)
Productos Agrícolas/crecimiento & desarrollo , Tecnología de Sensores Remotos , Imágenes Satelitales , Zea mays/crecimiento & desarrollo , Estaciones del Año
11.
Bioresour Technol ; 330: 125011, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33773268

RESUMEN

Biomass chemical looping gasification (CLG) technology is an important utilization form of renewable energy. In order to obtain high-quality syngas, CaO/Fe2O3 was used as a composite oxygen carrier for biomass CLG in this study. The CLG experiment of corn straw and the study of oxygen carrier recycling were carried out, simultaneously, the reaction mechanism was further discussed. Results shown adding CaO to oxygen carrier could significantly improve the quality of syngas through increasing the H2 and reduce Greenhouse gas (CO2 and CH4, about 14% reduction). Besides, the ratio of Fe2O3 to CaO, steam to biomass, and oxygen carrier to biomass all affected the syngas composition (the H2/CO variation from 1.82 to 2.19), while the temperature had obvious influence on the gas yield of CLG. The most possible reaction mechanism shown that the variation of Ca might be the main factor of gas composition fluctuation.


Asunto(s)
Oxígeno , Zea mays , Biomasa , Compuestos de Calcio , Compuestos Férricos , Gases , Óxidos , Vapor
12.
Ecotoxicol Environ Saf ; 214: 112096, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33647854

RESUMEN

Nicosulfuron is an ingredient in photosynthesis-inhibiting herbicides and has been widely used in corn post-emergence weed control. In the current study, a pair of sister lines, HK301 (nicosulfuron-tolerence, NT) and HK320 (nicosulfuron-sensitive, NS), was used to study the effect of nicosulfuron in sweet maize seedlings on C4 photosynthetic enzymes and non-enzymatic substances, expression levels of key enzymes, and chloroplast structure. Nicosulfuron was sprayed at the four-leaf stage, and water was sprayed as a control. After nicosulfuron treatment, phosphoenolpyruvate carboxylase (PEPC), NADP-malic dehydrogenase (NADP-MDH), NADP-malic enzyme (NADP-ME), pyruvate orthophosphate dikinase (PPDK), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities of NT were significantly higher than those of NS. Compared to NT, malate, oxaloacetic acid, and pyruvic acid significantly decreased as exposure time increased in NS. Compared to NS, nicosulfuron treatment significantly increased the expression levels of PEPC, NADP-MDH, NADP-ME, PPDK, and Rubisco genes in NT. Under nicosulfuron treatment, chloroplast ultrastructure of NS, compared to that of NT, nicosulfuron induced swelling of the chloroplast volume and reduced starch granules in NS. In general, our results indicate that in different resistant sweet maize, C4 photosynthetic enzymes activity and key genes expression play a critical role in enhancing the adaptability of plants to nicosulfuron stress at a photosynthetic physiological level.


Asunto(s)
Piridinas/toxicidad , Compuestos de Sulfonilurea/toxicidad , Zea mays/fisiología , Aclimatación , Adaptación Fisiológica , Malato Deshidrogenasa , Fosfoenolpiruvato Carboxilasa/genética , Fosfoenolpiruvato Carboxilasa/metabolismo , Fotosíntesis/genética , Hojas de la Planta/metabolismo , Piruvato Ortofosfato Diquinasa/genética , Piruvato Ortofosfato Diquinasa/metabolismo , Ribulosa-Bifosfato Carboxilasa/metabolismo , Plantones/metabolismo , Zea mays/metabolismo
13.
Food Chem ; 352: 129353, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33662915

RESUMEN

The research aimed to study the effect of stevia, xylitol, and corn syrup on the physical, physicochemical, and sensory properties of velvet tamarind chewy candy (VTCC). The content of sweeteners was optimized using stevia (5.5-6%), xylitol (5.5-6%), and corn syrup (7.5-8.5%) by mixture design (d-optimal) with 3 centerpoints and response surface methodology (RSM). The sweeteners in optimized VTCC consisted of velvet tamarind powder (40.5%), water (40%), stevia (6%), xylitol (6%), and corn syrup (7.5%) which provided the approximation error between prediction and observation values: of color (a* and b*), hardness, adhesiveness, gumminess, bioactive activities, and sensory properties within the range of 0.07-9.69%. The optimized VTCC using stevia and xylitol can reduce the sugar content by up to 60%. The sensory preference scores of VTCC from consumer acceptance were slightly like (6.1-6.9) which indicated that the VTCC with stevia and xylitol can provide satisfaction in all evaluated attributes and can be applied to this concept to create fruit chewy candy using stevia and xylitol.


Asunto(s)
Dulces/análisis , Diterpenos de Tipo Kaurano/química , Glucósidos/química , Edulcorantes/química , Tamarindus/química , Xilitol/química , Zea mays/química , Humanos
14.
Carbohydr Polym ; 260: 117801, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712149

RESUMEN

Slowly digestible starches have received interest due to their lower increase of postprandial blood glucose and insulin levels and, hence, modification of starches towards slower digestibility has commercial interest. However, chemical characteristics driving enzymatic (digestive) degradation are not fully unraveled. The digestion properties of starches have been linked to their crystalline type, chain length distribution, amylose content or degree of branching, but content and length of relatively long side-chains in amylopectin has not been paid attention to. Therefore, this research focusses on the unique content and length of amylopectin side-chains from conventional and new starch sources (potato, corn, pea, and tulip) correlated to the enzymatic digestion. The rate of hydrolysis was found to be correlated with the crystalline type of starch, as previously suggested, however, the complete hydrolysis of all starches, independent of the crystalline type and source, was shown to be governed by the content of longer amylopectin chains.


Asunto(s)
Gelatina/química , Glucano 1,4-alfa-Glucosidasa/metabolismo , Almidón/metabolismo , alfa-Amilasas/metabolismo , Cristalización , Digestión , Hidrólisis , Espectroscopía de Resonancia Magnética , Guisantes/metabolismo , Solanum tuberosum/metabolismo , Almidón/química , Zea mays/metabolismo
15.
Ecotoxicol Environ Saf ; 214: 112112, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33714140

RESUMEN

Sole biochar addition or microbial inoculation as a soil amendment helps to reduce cadmium (Cd) toxicity in polluted agricultural soils. Yet the synergistic effects of microorganisms and biochar application on Cd absorption and plant productivity remain unclear. Therefore, a pot experiment was conducted to investigate the combined effect of microorganisms (Trichoderma harzianum L. and Bacillus subtilis L.), biochar (maize straw, cow manure, and poultry manure), and Cd (0, 10, and 30 ppm) on plant physiology and growth to test how biochar influences microbial growth and plant nutrient uptake, and how biochar ameliorates under Cd-stressed soil. Results showed that in comparison to non-Cd polluted soil, the highest reduction in chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, and intercellular CO2 were observed in Cd2 (30 ppm), which were 9.34%, 22.95%, 40.45%, 29.07%, 20.67%, and 22.55% respectively less than the control Cd0 (0 ppm). Among sole inoculation of microorganisms, highest stomatal conductance, water use efficiency, and intercellular CO2 were recorded with combined inoculation of both microorganisms (M3), which were 5.92%, 7.65%, and 7.28% respectively higher than the control, and reduced the Cd concentration in soil, root, and shoot by 21.34%, 28.36%, and 20.95%, respectively, compared to the control. Similarly, co-application of microorganisms and biochar ameliorated the adverse effect of Cd in soybean as well as significantly improved plant biomass, photosynthetic activity, nutrient contents, and antioxidant enzyme activities, and minimized the production of reactive oxygen species and Cd content in plants. Soil amended with poultry manure biochar had significantly improved the soil organic carbon, total nitrogen, total phosphorous, and available potassium by 43.53%, 36.97%, 22.28%, and 4.24%, respectively, and decreased the concentration of Cd in plant root and shoot by 34.68% and 47.96%, respectively, compared to the control. These findings indicate that the combined use of microorganisms and biochar as an amendment have important synergistic effects not only on the absorption of nutrients but also on the reduction of soybean Cd intake, and improve plant physiology of soybean cultivated in Cd-polluted soils as compared to sole application of microorganisms or biochar.


Asunto(s)
Bacillus subtilis , Cadmio/análisis , Carbón Orgánico , Hypocreales , Contaminantes del Suelo/análisis , Soja/crecimiento & desarrollo , Soja/metabolismo , Cadmio/metabolismo , Estiércol , Nitrógeno/metabolismo , Fósforo/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/metabolismo , Potasio/metabolismo , Contaminantes del Suelo/metabolismo , Zea mays
16.
Adv Exp Med Biol ; 1261: 95-113, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33783733

RESUMEN

Multi-gene transformation methods need to be able to introduce multiple transgenes into plants in order to reconstitute a transgenic locus where the introduced genes express in a coordinated manner and do not segregate in subsequent generations. This simultaneous multiple gene transfer enables the study and modulation of the entire metabolic pathways and the elucidation of complex genetic control circuits and regulatory hierarchies. We used combinatorial nuclear transformation to produce multiplex-transgenic maize plants. In proof of principle experiments, we co-expressed five carotenogenic genes in maize endosperm. The resulting combinatorial transgenic maize plant population, equivalent to a "mutant series," allowed us to identify and complement rate-limiting steps in the extended endosperm carotenoid pathway and to recover corn plants with extraordinary levels of ß-carotene and other nutritionally important carotenoids. We then introgressed the induced (transgenic) carotenoid pathway in a transgenic line accumulating high levels of nutritionally important carotenoids into a wild-type yellow-endosperm variety with a high ß:ε ratio. Novel hybrids accumulated zeaxanthin at unprecedented amounts. We introgressed the same pathway into a different yellow corn line with a low ß:ε ratio. The resulting hybrids, in this case, had a very different carotenoid profile. The role of genetic background in determining carotenoid profiles in corn was elucidated, and further rate-limiting steps in the pathway were identified and resolved in hybrids. Astaxanthin accumulation was engineered by overexpression of a ß-carotene ketolase in maize endosperm. In early experiments, limited astaxanthin accumulation in transgenic maize plants was attributed to a bottleneck in the conversion of adonixanthin (4-ketozeaxanthin) to astaxanthin. More recent experiments showed that a synthetic ß-carotene ketolase with a superior ß-carotene/zeaxanthin ketolase activity is critical for the high-yield production of astaxanthin in maize endosperm. Engineered lines were used in animal feeding experiments which demonstrated not only the safety of the engineered lines but also their efficacy in a range of different animal production applications.


Asunto(s)
Endospermo , Zea mays , Animales , Carotenoides/metabolismo , Endospermo/genética , Endospermo/metabolismo , Redes y Vías Metabólicas , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Zea mays/genética , Zea mays/metabolismo
17.
Animal ; 15(3): 100147, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33785183

RESUMEN

Digestibility of amino acids (AA) in feed ingredients for pigs has been generally determined by feeding experimental diets containing test feedstuffs as a sole source of N, which may lead to the deficiency or imbalance of AA and hinder an accurate determination of digestibility values. Therefore, the addition of casein in experimental diets may ameliorate the potential negative effects of deficiency or imbalance of AA. In addition, the concentration of test feedstuffs in experimental diets may affect the digestibility of AA in test feedstuffs. Two experiments were conducted with corn distillers' dried grains with solubles (DDGS) as the test feedstuff to determine the effects of increasing concentrations of casein in experimental diets on standardized ileal digestibility (SID) of AA in DDGS (experiment 1) and to investigate the effects of two concentrations of DDGS in experimental diets with or without the addition of casein on SID of AA in DDGS (experiment 2). In experiment 1, 20 barrows (initial BW = 45.3 ±â€¯1.80 kg) surgically fitted with T-cannulas at the distal ileum were allocated to a quadruplicate 5 × 2 incomplete Latin square design with five diets and two periods. Four isonitrogenous diets containing increasing concentrations of casein from 0 to 165 g/kg with decreasing concentrations of DDGS from 466.8 to 0 g/kg and a N-free diet were prepared. The SID of AA, except for arginine, cysteine, and glycine, in DDGS linearly decreased (P < 0.05) with increasing concentrations of casein in experimental diets. Quadratic response (P = 0.023) was observed in the SID of lysine in DDGS when the concentration of casein in experimental diets increased. In experiment 2, the same 20 barrows (initial BW = 52.8 ±â€¯2.99 kg) and experimental design as experiment 1 were used with different diets, which were prepared as a 2 × 2 factorial arrangement with the concentration of DDGS at 466.8 or 155.6 g/kg and that of casein at 0 or 110 g/kg. Regardless of the addition of casein, pigs fed experimental diets containing 466.8 g/kg DDGS had greater (P < 0.01) SID of indispensable AA, except for tryptophan, in DDGS than those fed diets containing 155.6 g/kg DDGS. In conclusion, the addition of casein in experimental diets did not affect the SID of AA in DDGS, whereas the SID of AA in DDGS decreased as the concentration of DDGS in diets decreased.


Asunto(s)
Aminoácidos , Alimentación Animal , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Caseínas , Dieta/veterinaria , Digestión , Íleon , Porcinos , Zea mays
18.
Braz J Biol ; 82: e232612, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33787711

RESUMEN

Three experiments were done with different particle sizes of corn feed on its zootechnical performance, passing rate and apparent digestibility of juvenile tambaqui (Colossoma macropomum). In the first, 200 juveniles were used and distributed in 20 tanks (220 L), 10 fish per unit (four replicates). The experimental system used to record passage time was composed of five incubators with 200 L. In the second, 75 juveniles were used per 55 days (three replications). In the third, 75 juveniles were used and distributed in five incubators of 200 L. All experiments were performed randomly. Different linear behavior treatments were observed for apparent digestibility of crude protein; and the smaller particle size (150 µm) had better results digestibility. smaller particle size of the corn had better results, affected the growth performance of tambaqui and the apparent digestibility of crude protein and ether extract. Thus, is recommended that a particle size of 150 µm of corn be used for tambaqui.


Asunto(s)
Characiformes , Zea mays , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Tamaño de la Partícula
19.
An Acad Bras Cienc ; 93(1): e20190686, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33787751

RESUMEN

The corn leafhopper Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae), transmits three important plant pathogens that adversely affect corn crop and ranges from the USA to Argentina. The vector has a rich natural enemy complex that generates high levels of parasitism, but its populations are persistent and prevalent. We characterized the oviposition sites of D. maidis on young corn plants in order to verify the hypothesis that the vector has an oviposition strategy for mitigating parasitism. Oviposition locations on plants were assessed in the laboratory and eggs within corn plants were exposed to natural parasitism in a cornfield. Eggs were located mostly laid in the unfolded leaves and were attacked by five parasitoid species. Parasitism was significantly affected by the class of leaf and the position of the egg in the leaf. Anagrus virlai Triapitsyn was the most abundant parasitoid species, which emerged significantly higher in the basal blade than other species. Our results suggest that leafhoppers minimize egg parasitism by laying their eggs within concealed locations on the plant.


Asunto(s)
Hemípteros , Himenópteros , Animales , Argentina , Femenino , Oviposición , Zea mays
20.
Molecules ; 26(4)2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33672045

RESUMEN

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through 13C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.


Asunto(s)
Espectroscopía de Resonancia Magnética con Carbono-13 , Carbón Orgánico/química , Carbón Orgánico/farmacología , Cromatografía de Gases y Espectrometría de Masas , Desarrollo de la Planta/efectos de los fármacos , Compuestos de Amonio Cuaternario/química , Agua/química , Bioensayo , Raíces de Plantas/anatomía & histología , Raíces de Plantas/efectos de los fármacos , Brotes de la Planta/anatomía & histología , Brotes de la Planta/efectos de los fármacos , Semillas/efectos de los fármacos , Zea mays/efectos de los fármacos , Zea mays/crecimiento & desarrollo
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