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1.
PLoS One ; 15(8): e0238042, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841280

RESUMO

Long-term chemical fertilizer input causes soil organic matter losses, structural compaction, and changes in soil water and nutrient availability, which have been subdued in the most of dry farmland in China. The concept of "more efficiency with less fertilizer input" has been proposed and is urgently needed in current agriculture. Application of chemical fertilizer combined with organic manure (OM) could be a solution for soil protection and sustainable production of dry-land maize (Zea mays. L). Field research over three consecutive years on the Loess Plateau of China was conducted to evaluate the integrated effects of chemical fertilizer strategies and additional OM input on soil nutrients availability and water use in maize. The results showed that, after harvest, soil bulk density decreased significantly with OM application, concomitant with 11.9, 18.7 and 97.8% increases in topsoil total nitrogen, organic matter, and available phosphorus contents, respectively, compared with those under equal chemical NPK input. Water use in the 1.0-1.5 m soil profile was improved, therefore, the soil conditions were better for maize root growth, leaf area and shoot biomass of individual maize plants increased significantly with OM application. Optimized NPK strategies increased grain yield and water use efficiency by 18.5 and 20.6%, respectively, compared to only chemical NP input. Furthermore, additional OM input promoted yield and water use efficiency by 8.9 and 5.8%, respectively. Addition of OM promotes sustainable soil and maize grain productivity as well as friendly soil environmental management of dry land farming.


Assuntos
Esterco/análise , Nutrientes/metabolismo , Compostos Orgânicos/farmacologia , Solo/química , Água/análise , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Biomassa , China , Fertilizantes/análise , Nitrogênio/metabolismo , Fósforo/metabolismo , Desenvolvimento Sustentável , Zea mays/metabolismo
2.
Ecotoxicol Environ Saf ; 204: 111148, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32818843

RESUMO

To disclose how phosphorus deficiency influence phytoremediation of Cd contamination using poplars, root architecture, Cd absorption, Cd translocation and antioxidant defense in poplar roots were investigated using a clone of Populus × euramericana. Root growth was unaltered by Cd exposure regardless of P conditions, while the degree of root proliferation upon P deficiency was changed by high level of Cd exposure. The concentration and content of Cd accumulation in roots were increased by P deficiency. This can be partially explained by the increased expression of genes encoding PM H + -ATPase under the combined conditions of P deficiency and high Cd exposure, which enhanced Cd2+-H+ exchanges and led to an increment of Cd uptake under P deficiency. Despite of the increasing Cd accumulation in roots, the translocation of Cd from roots to aerial tissues sharply decreased upon P deficiency. The relative expression of genes responsible for Cd translocation (HMA4) decreased upon P deficiency and thus inhibited Cd translocation via xylem. GR activity was decreased by P deficiency, which can inhibit the form of GSH and GSH-Cd complexes and decrease Cd translocation via GSH-Cd complexes. The transportation of PC-Cd complexes into vacuole decreased under P deficiency as a result of the low expression of PCS and ABCC1, and thus suppressed Cd tolerance and Cd detoxification in roots. Moreover, P deficiency decreased the levels of antioxidase (GR and CAT) and phytohormones including JA, ABA and GA3, which synchronously reduced antioxidant capacity in roots.


Assuntos
Cádmio/metabolismo , Fósforo/metabolismo , Populus/fisiologia , Adaptação Fisiológica , Antioxidantes/metabolismo , Biodegradação Ambiental , Transporte Biológico , Cádmio/toxicidade , Proliferação de Células , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/metabolismo , Populus/metabolismo , Xilema/metabolismo
3.
PLoS One ; 15(7): e0232860, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645001

RESUMO

Limited information is available that seed biopriming with plant growth-promoting Enterobacter spp. play a prominent role to enhance vegetative growth of plants. Contrary to Enterobacter cloacae, Enterobacter hormaechei is a less-studied counterpart despite its vast potential in plant growth-promotion mainly through the inorganic phosphorus (P) and potassium (K) solubilization abilities. To this end, 18 locally isolated bacterial pure cultures were screened and three strains showed high P- and K-solubilizing capabilities. Light microscopy, biochemical tests and 16S rRNA gene sequencing revealed that strains 15a1 and 40a were closely related to Enterobacter hormaechei while strain 38 was closely related to Enterobacter cloacae (Accession number: MN294583; MN294585; MN294584). All Enterobacter spp. shared common plant growth-promoting traits, namely nitrogen (N2) fixation, indole-3-acetic acid production and siderophore production. The strains 38 and 40a were able to produce gibberellic acid, while only strain 38 was able to secrete exopolysaccharide on agar. Under in vitro germination assay of okra (Abelmoschus esculentus) seeds, Enterobacter spp. significantly improved overall germination parameters and vigor index (19.6%) of seedlings. The efficacy of root colonization of Enterobacter spp. on the pre-treated seedling root tips was confirmed using Scanning Electron Microscopy (SEM). The pot experiment of bioprimed seeds of okra seedling showed significant improvement of the plant growth (> 28%) which corresponded to the increase of P and K uptakes (> 89%) as compared to the uninoculated control plants. The leaf surface area and the SPAD chlorophyll index of bioprimed plants were increased by up to 29% and 9% respectively. This report revealed that the under-explored species of P- and K-solubilizing Enterobacter hormaechei sp. with multiple plant beneficial traits presents a great potential sustainable approach for enhancement of soil fertility and P and K uptakes of plants.


Assuntos
Abelmoschus/crescimento & desenvolvimento , Enterobacter/fisiologia , Fósforo/metabolismo , Potássio/metabolismo , Sementes/microbiologia , Abelmoschus/classificação , Abelmoschus/metabolismo , Abelmoschus/microbiologia , Contenção de Riscos Biológicos , Enterobacter/isolamento & purificação , Germinação , Tipagem Molecular , Desenvolvimento Vegetal , RNA Ribossômico 16S , Plântula/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento
4.
Clín. investig. arterioscler. (Ed. impr.) ; 32(3): 129-134, mayo-jun. 2020. ilus
Artigo em Espanhol | IBECS | ID: ibc-193359

RESUMO

La enfermedad renal crónica representa un verdadero estado inflamatorio y está relacionada con múltiples factores de riesgo cardiovascular. La enfermedad arterial coronaria es una de sus principales complicaciones y usualmente ha sido asociada con factores de riesgo cardiovascular no clásicos o propios de pacientes urémicos como las alteraciones del metabolismo del calcio y el fósforo, entre otros. Evidencia clínica reciente muestra que el depósito de grasa órgano específico, como el tejido adiposo epicárdico, es un factor de riesgo adicional a tener en cuenta en el momento de la evaluación de riesgo cardiovascular en la población general y en los pacientes renales. La interacción directa de este tejido con los vasos coronarios y la consecuente mediación de sustancias proaterogénicas generan un proceso local que termina en la producción de daño endotelial. Aunque la población de enfermos renales ha sido evaluada escasamente, estudios futuros determinarán con precisión si un incremento en la adiposidad epicárdica está verdaderamente asociado a la morbimortalidad cardiovascular en este grupo de riesgo


Chronic kidney disease represents a true inflammatory state, and is related to multiple cardiovascular risk factors. Coronary artery disease is the major complication, and has usually been associated with non-classical or uraemic related factors that include the disturbance of calcium and phosphorus metabolism, among others. Recent clinical evidence shows that specific body fat deposition like epicardial adipose tissue is an additional factor to consider when evaluating cardiovascular risk in the general population and kidney patients. Direct interaction of this tissue and coronary vessels with consequent mediation of pro-atherogenic substances have a local process ending in endothelial damage. Although the population of renal patients has been poorly evaluated, future studies should determine precisely whether an increase in epicardial fat is truly associated with cardiovascular morbidity and mortality in this risk group


Assuntos
Humanos , Tecido Adiposo , Tecido Adiposo/metabolismo , Síndrome Metabólica/complicações , Insuficiência Renal Crônica/complicações , Doença da Artéria Coronariana/complicações , Gordura Subcutânea , Fatores de Risco , Cálcio/metabolismo , Fósforo/metabolismo , Pericárdio/fisiopatologia , Pericárdio/diagnóstico por imagem , Obesidade/fisiopatologia
5.
Ecotoxicol Environ Saf ; 201: 110830, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32559689

RESUMO

Iron (Fe) oxides are intimately coupled with phosphorus and closely associated with the bioavailability of potential toxic elements (PTEs) in soil. Thus, Fe oxides may influence the stabilization of PTEs in contaminated soils amended by phosphorus. To evaluate the effects of hematite (HMT) on the stabilization of PTEs, 1-5% (by weight) of HMT was added into a contaminated red soil amended with hydroxyapatite (HAP) to simulate naturally occurring Fe oxides. The stabilization efficiencies of soil copper (Cu) and cadmium (Cd) amended with HAP in soils with low, moderate, and high content of HMT were assessed after a 60-day incubation. HAP treated the soil with high rate HMT decreased the CaCl2-extractable and acid-soluble fractions of Cu and Cd than that of HAP alone. In particular, CaCl2-extactable Cu and Cd in the soil with 5% HMT amended by HAP were 91-95% and 41-68% lower than those amended with only HAP. High content of HMT in soil could decrease the concentration of labile phosphorus in the presence of HAP, but it did not increase the concentration of NaOH-extractable inorganic phosphorus (the fraction bound to Fe oxides). The concentrations of free and crystalline Fe oxides were significantly increased by adding high dosages of HMT with or without HAP. High content of HMT in soil amended by HAP reduced metal phytotoxicity and uptake by wheat shoots than the soil containing HAP without HMT. The results indicate that HMT can promote Cu and Cd stabilization while decrease labile phosphorus in red soil amended with HAP, suggesting that phosphorus-based amendments combined with Fe oxides can be used to stabilize PTEs in contaminated red soils.


Assuntos
Cádmio/análise , Cobre/análise , Durapatita/química , Compostos Férricos/química , Fósforo/análise , Poluentes do Solo/análise , Disponibilidade Biológica , Cádmio/metabolismo , China , Cobre/metabolismo , Fósforo/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Triticum/efeitos dos fármacos , Triticum/metabolismo
6.
Chemosphere ; 257: 127076, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32485516

RESUMO

The effect of acetate (HAc) and propionate (HPr) on denitrifying phosphorus removal (DPR) was evaluated in a novel two-sludge A2/O - MBBR (anaerobic/anoxic/oxic - moving bed biofilm reactor) system. Results showed that it was the carbon source transformation and utilization especially the composition of poly-ß-hydroxyalkanoates (PHA) (mainly poly-ß-hydroxybutyrate (PHB) and poly-bhydroxyvalerate (PHV)) decided DPR performance, where the co-exist of HAc and HPr promoted the optimal nitrogen (85.77%) and phosphorus (91.37%) removals. It facilitated the balance of PHB and PHV and removing 1 mg NO3- (PO43-) consumed 3.04-4.25 (6.84-9.82) mgPHA, where approximately 40-45% carbon source was saved. Mass balance revealed the main metabolic pathways of carbon (MAn,C (consumed amount in anaerobic stage) and MA-O,C (consumed amount in anoxic and oxic stages): 66.38-76.19%), nitrogen (MDPR,N (consumed amount in DPR): 57.01-65.75%), and phosphorus (MWS,P (discharged amount in waste sludge): 81.05-85.82%). Furthermore, the relative abundance and microbial distribution were assessed to elucidate DPR mechanism (e.g. Accumulibacter, Acinetobacter, Dechloromonas, Competibacter, and Defluviicoccus) in the A2/O reactor and nitrification performance (e.g. Nitrosomonas, Nitrosomonadaceae and Nitrospira) in the MBBR. Carbon source was demonstrated as the key point to stimulate the biodiversity and bioactivity related to DPR potential, and the operational strategy of carbon source addition was proposed based on the utilizing rules of HAc and HPr.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Acetatos , Bactérias/metabolismo , Biofilmes , Reatores Biológicos , Carbono , Desnitrificação , Microbiota , Nitrificação , Nitrogênio/metabolismo , Nutrientes , Fósforo/metabolismo , Propionatos , Esgotos
7.
PLoS One ; 15(6): e0234216, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32492072

RESUMO

The role of root exudates has long been recognized for its potential to improve nutrient use efficiency in cropping systems. However, studies addressing the variability of root exudates involved in phosphorus solubilization across plant developmental stages remain scarce. Here, we grew Arabidopsis thaliana seedlings in sterile liquid culture with a low, medium, or high concentration of phosphate and measured the composition of the root exudate at seedling, vegetative, and bolting stages. The exudates changed in response to the incremental addition of phosphorus, starting from the vegetative stage. Specific metabolites decreased in relation to phosphate concentration supplementation at specific stages of development. Some of those metabolites were tested for their phosphate solubilizing activity, and 3-hydroxypropionic acid, malic acid, and nicotinic acid were able to solubilize calcium phosphate from both solid and liquid media. In summary, our data suggest that plants can release distinct compounds to deal with phosphorus deficiency needs influenced by the phosphorus nutritional status at varying developmental stages.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Fósforo/metabolismo , Exsudatos de Plantas/metabolismo , Raízes de Plantas/metabolismo , Fosfatos de Cálcio/química , Fosfatos de Cálcio/metabolismo , Fertilizantes , Fosfatos/farmacocinética , Exsudatos de Plantas/análise , Solubilidade
8.
PLoS One ; 15(6): e0234870, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32569317

RESUMO

Mucoromycota fungi possess a versatile metabolism and can utilize various substrates for production of industrially important products, such as lipids, chitin/chitosan, polyphosphates, pigments, alcohols and organic acids. However, as far as commercialisation is concerned, establishing industrial biotechnological processes based on Mucoromycota fungi is still challenging due to the high production costs compared to the final product value. Therefore, the development of co-production concept is highly desired since more than one valuable product could be produced at the time and the process has a potentially higher viability. To develop such biotechnological strategy, we applied a high throughput approach consisting of micro-titre cultivation and FTIR spectroscopy. This approach allows single-step biochemical fingerprinting of either fungal biomass or growth media without tedious extraction of metabolites. The influence of two types of nitrogen sources and different levels of inorganic phosphorus on the co-production of lipids, chitin/chitosan and polyphosphates for nine different oleaginous Mucoromycota fungi was evaluated. FTIR analysis of biochemical composition of Mucoromycota fungi and biomass yield showed that variation in inorganic phosphorus had higher effect when inorganic nitrogen source-ammonium sulphate-was used. It was observed that: (1) Umbelopsis vinacea reached almost double biomass yield compared to other strains when yeast extract was used as nitrogen source while phosphorus limitation had little effect on the biomass yield; (2) Mucor circinelloides, Rhizopus stolonifer, Amylomyces rouxii, Absidia glauca and Lichtheimia corymbifera overproduced chitin/chitosan under the low pH caused by the limitation of inorganic phosphorus; (3) Mucor circinelloides, Amylomyces rouxii, Rhizopus stolonifer and Absidia glauca were able to store polyphosphates in addition to lipids when high concentration of inorganic phosphorus was used; (4) the biomass and lipid yield of high-value lipid producers Mortierella alpina and Mortierella hyalina were significantly increased when high concentrations of inorganic phosphorus were combined with ammonium sulphate, while the same amount of inorganic phosphorus combined with yeast extract showed negative impact on the growth and lipid accumulation. FTIR spectroscopy revealed the co-production potential of several oleaginous Mucoromycota fungi forming lipids, chitin/chitosan and polyphosphates in a single cultivation process.


Assuntos
Biotecnologia/métodos , Técnicas de Cultura de Células/métodos , Quitina/biossíntese , Fungos , Lipídeos/biossíntese , Polifosfatos/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Meios de Cultura , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo
9.
Anim Sci J ; 91(1): e13391, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32558027

RESUMO

One hundred Yorkshire × Landrace sows were randomly assigned to one of two dietary treatments (diet ND: 6,000 IU vitamin D3 /d feed; diet 25-D: 200 µg/day 25OHD3 feed). The experiment began on d 90 of gestation and continued until weaning on day 21 of lactation. In sows that received 25OHD3 , the growth rate of the piglets before weaning was significantly accelerated (0.266 kg/day, p < .05). Sow serum was collected after weaning, and those in the 25OHD3 group were found to have significantly higher serum calcium (CA) and phosphorus (PI) levels (p < .05). Interestingly, the oestrus cycle of sows fed 25OHD3 was significantly shortened (p < .05), the oestrus time was concentrated on the fifth day after weaning, and the piglets were born with a higher degree of uniformity (p < .05). Colostrum was collected on the day of delivery, and the colostrum of sows fed 25OHD3 contained higher milk fat content than the control group (p < .05). 25OHD3 supplementation increased the mRNA and protein expression of INSIG1 and SREBP1, which regulate milk fat synthesis, in the mammary gland of lactating sows (p < .05). In conclusion, 25OHD3 supplementation in maternal diets improved reproductive performance, milk fat content and the mRNA and protein levels of genes regulating milk fat synthesis in lactating sows.


Assuntos
25-Hidroxivitamina D 2/administração & dosagem , 25-Hidroxivitamina D 2/farmacologia , Fenômenos Fisiológicos da Nutrição Animal/genética , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Dieta/veterinária , Suplementos Nutricionais , Expressão Gênica/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lactação/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Reprodução/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Suínos/genética , Suínos/fisiologia , Animais , Cálcio/metabolismo , Estro/efeitos dos fármacos , Feminino , Glicolipídeos/metabolismo , Glicoproteínas/metabolismo , Lactação/fisiologia , Fósforo/metabolismo , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
10.
Chemosphere ; 257: 127097, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470541

RESUMO

The feasibility of simultaneous partial nitrification, denitrification and phosphorus removal (SPNDPR) process was investigated in a single-stage anaerobic/micro-aerobic sequencing batch reactor for treating real sewage. Partial nitrification was maintained with average nitrite accumulation ratio of 90.3% during 266 days' operation. Removal efficiencies for NH4+-N (96.3%), total inorganic nitrogen (81.4%), and phosphorus (91.0%) were stably obtained when treated real sewage with low carbon/nitrogen (3.4), with simultaneous partial nitrification and denitrification efficiency of 73.1%. The mechanism analysis revealed that denitrifying glycogen-accumulating organisms (DGAOs) and denitrifying polyphosphate-accumulating organisms (DPAOs) played the main roles in N-removal and P-removal, respectively. Nitrite pathway and optimized use of the organic carbon available in the sewage were keys for the successful performance. Further microbial community illustrating that DGAOs Candidatus_Competibacter, DPAOs Dechloromonas, and ammonia-oxidizing bacteria Nitrosomonadaceae were main functional groups. Notably, sludge granulation was formed under long-term synchronous low dissolved oxygen and low sludge loading conditions, avoiding sludge bulking.


Assuntos
Eliminação de Resíduos Líquidos , Anaerobiose , Reatores Biológicos/microbiologia , Carbono , Desnitrificação , Nitrificação , Nitritos , Nitrogênio/metabolismo , Nutrientes , Oxigênio , Fósforo/metabolismo , Esgotos
11.
Nat Commun ; 11(1): 2594, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444651

RESUMO

Development of multicellularity was one of the major transitions in evolution and occurred independently multiple times in algae, plants, animals, and fungi. However recent comparative genome analyses suggest that fungi followed a different route to other eukaryotic lineages. To understand the driving forces behind the transition from unicellular fungi to hyphal forms of growth, we develop a comparative model of osmotrophic resource acquisition. This predicts that whenever the local resource is immobile, hard-to-digest, and nutrient poor, hyphal osmotrophs outcompete motile or autolytic unicellular osmotrophs. This hyphal advantage arises because transporting nutrients via a contiguous cytoplasm enables continued exploitation of remaining resources after local depletion of essential nutrients, and more efficient use of costly exoenzymes. The model provides a mechanistic explanation for the origins of multicellular hyphal organisms, and explains why fungi, rather than unicellular bacteria, evolved to dominate decay of recalcitrant, nutrient poor substrates such as leaf litter or wood.


Assuntos
Fungos/citologia , Fungos/fisiologia , Modelos Biológicos , Carbono/metabolismo , Citoplasma/metabolismo , Fungos/crescimento & desenvolvimento , Hifas/citologia , Hifas/crescimento & desenvolvimento , Nitrogênio/metabolismo , Fósforo/metabolismo
12.
Artigo em Inglês | MEDLINE | ID: mdl-32464490

RESUMO

Soil phosphorus (P) occurs in pools of lower availability due to soil P fixation and therefore, it is a key constrain to crop production. Long term molybdenum-induced effects in wheat and rhizosphere/non-rhizosphere soil P dynamics have not yet been investigated. Here, a long term field experiment was conducted to explore these effects in wheat consisting of two treatments i.e. with molybdenum (+Mo) and without molybdenum (-Mo). The results revealed that molybdenum (Mo) supply increased plant biomass, grain yield, P uptake, preserved the configuration of chloroplast, stomata, and mesophyll tissue cells, suggesting the complementary effects of Mo on wheat yield and P accumulation. During the periods of vegetative growth, soil organic carbon, organic matter, and microbial biomass P were higher and tended to decrease in rhizosphere soil at maturity stage. In +Mo treatment, the most available P fractions [H2O-Pi (16.2-22.9 mg/kg and 4.24-7.57 mg/kg) and NaHCO3-Pi (130-149 mg/kg and 77.2-88 mg/kg)] were significantly increased in rhizosphere and non-rhizosphere soils, respectively. In addition, the +Mo treatment significantly increased the acid phosphatase activity and the expression of phoN/phoC, aphA, olpA/lppC gene transcripts in rhizosphere soil compared to -Mo. Our research findings suggested that Mo application has increased P availability not only through biochemical and chemical changes in rhizosphere but also through P assimilation and induced effects in the leaf ultra-structures. So, it might be a strategy of long term Mo fertilizer supply to overcome the P scarcity in plants and rhizosphere soil.


Assuntos
Molibdênio/farmacologia , Fósforo/metabolismo , Folhas de Planta/ultraestrutura , Rizosfera , Triticum/efeitos dos fármacos , Carbono , Solo , Triticum/metabolismo
13.
Ecotoxicol Environ Saf ; 197: 110563, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32278824

RESUMO

Sodium sulfide (Na2S) is usually used as an amendment in industrial sewage treatment. To evaluate the effects of Na2S on the growth of Robinia pseudoacacia (black locust), heavy metal immobilization, and soil microbial activity, the R. pseudoacacia biomass and nutrient content and the soil heavy metal bioavailability, enzyme activity, and arbuscular mycorrhizal (AM) fungal community were measured by a single-factor pot experiment. The Pb-Zn-contaminated soil was collected from a Pb-Zn mine that had been remediated by R. pseudoacacia for five years. Three pollution levels (unpolluted, mildly polluted, and severely polluted) were evaluated by the pollution load index. Na2S application increased the shoot biomass under severe and mild contamination. In soil, Na2S application decreased the bioavailable Pb and Zn contents under severe and mild contamination, which resulted in a decrease in the Pb and Zn content in R. pseudoacacia. However, Na2S application did not affect the total Pb content per plant and enhanced the total Zn content per plant because of the higher biomass of the plants under Na2S application. Increased phosphatase activity and increased available phosphorous content may promote the uptake of phosphorus in R. pseudoacacia. Moreover, Na2S application is beneficial to the diversity of AM fungi under mild and severe pollution. Overall, Na2S application has great potential for enhancing soil heavy metal immobilization, enhancing soil microbial activity, and improving the growth of R. pseudoacacia in polluted soils. Therefore, Na2S is suitable for use in Pb-Zn remediation to ameliorate environmental heavy metal pollution.


Assuntos
Metais Pesados/farmacocinética , Robinia/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/farmacocinética , Sulfetos/farmacologia , Biodegradação Ambiental , Disponibilidade Biológica , Biomassa , Chumbo/farmacocinética , Micorrizas/classificação , Micorrizas/efeitos dos fármacos , Fósforo/metabolismo , Robinia/efeitos dos fármacos , Robinia/metabolismo , Robinia/microbiologia , Zinco/farmacocinética
14.
Can J Microbiol ; 66(8): 475-489, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32223723

RESUMO

The aim of this study was to investigate the effects of a volcanic rock porous carrier (VRPC) on sludge reduction, pollutant removal, and microbial community structure in an anaerobic side-stream reactor (ASSR). Three lab-scale membrane bioreactors (MBRs), including an anoxic-oxic MBR, which served as the control (C-MBR), an ASSR-coupled MBR (A-MBR), and an A-MBR filled with VRPC (FA-MBR) were stably and simultaneously operated for 120 days. The effect of the three reactors on the removal of chemical oxygen demand (COD) was almost negligible (all greater than 95%), but the average removal efficiency of ammonium nitrogen, total nitrogen, and total phosphorus was significantly improved by the insertion of an ASSR, especially when the ASSR was filled with VRPC. Finally, A-MBR and FA-MBR achieved 16.2% and 26.4% sludge reduction rates, with observed sludge yields of 0.124 and 0.109 g mixed liquid suspended solids/g COD, respectively. Illumina MiSeq sequencing revealed that microbial diversity and richness were highest in the VRPC, indicating that a large number of microorganisms formed on the carrier surface in the form of a biofilm. Abundant denitrifying bacteria (Azospira, Comamonadaceae_unclassified, and Flavobacterium) were immobilized on the carrier biofilm, which contributed to increased nitrogen removal. The addition of a VRPC to the ASSR successfully immobilized abundant hydrolytic, fermentative, and slow-growing microorganisms, which all contributed to reductions in sludge yield.


Assuntos
Reatores Biológicos/microbiologia , Microbiota , Anaerobiose , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biodegradação Ambiental , Biofilmes , Fermentação , Hidrólise , Nitrogênio/metabolismo , Fósforo/metabolismo , Esgotos/microbiologia
15.
Ecotoxicol Environ Saf ; 196: 110537, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32272346

RESUMO

The objective of the study was to explore the influences of arbuscular mycorrhizae (AM), phosphorus (P) fertiliser, biochar application (BC) and their interactions on Medicago sativa growth, nutrient, Cd content and AM fungi-plant symbioses. Applications of both P fertiliser and BC significantly increased total biomass and P and potassium (K) uptake, regardless of AM. When no P fertiliser or BC was used, the shoot biomass and nitrogen (N), P, and K contents in the +AM treatments were 1.39, 1.54, 4.53 and 2.06 times higher than those in the -AM treatments, respectively. AM fungi only elevated the total P uptake by 44.03% when P fertiliser was applied at a rate of 30 mg P kg-1 in the absence of BC addition. With BC application or high-P fertiliser input (100 mg P kg-1), the soil available P was significantly higher than that in the other treatments, and AM fungi significantly reduced the shoot biomass. The minimum Cd concentration occurred in the shoots of alfalfas treated with BC and high-P fertiliser inputs; this concentration was lower than the maximum permitted concentration in China. Although the BC and high-P inputs could eliminate the positive mycorrhizal response, the results suggested that BC application in combination with high-P fertiliser input could not only increase forage yields but also lower Cd concentrations to meet the forage safety standards by the dilution effect.


Assuntos
Cádmio/metabolismo , Carvão Vegetal/farmacologia , Medicago sativa/crescimento & desenvolvimento , Micorrizas/fisiologia , Fósforo/farmacologia , Biomassa , Carvão Vegetal/análise , Fertilizantes/análise , Medicago sativa/efeitos dos fármacos , Medicago sativa/metabolismo , Medicago sativa/microbiologia , Nutrientes/metabolismo , Fósforo/análise , Fósforo/metabolismo , Poluentes do Solo/metabolismo , Simbiose/efeitos dos fármacos
16.
Proc Natl Acad Sci U S A ; 117(14): 7863-7870, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32229568

RESUMO

Nearly 20% of tropical forests are within 100 m of a nonforest edge, a consequence of rapid deforestation for agriculture. Despite widespread conversion, roughly 1.2 billion ha of tropical forest remain, constituting the largest terrestrial component of the global carbon budget. Effects of deforestation on carbon dynamics in remnant forests, and spatial variation in underlying changes in structure and function at the plant scale, remain highly uncertain. Using airborne imaging spectroscopy and light detection and ranging (LiDAR) data, we mapped and quantified changes in forest structure and foliar characteristics along forest/oil palm boundaries in Malaysian Borneo to understand spatial and temporal variation in the influence of edges on aboveground carbon and associated changes in ecosystem structure and function. We uncovered declines in aboveground carbon averaging 22% along edges that extended over 100 m into the forest. Aboveground carbon losses were correlated with significant reductions in canopy height and leaf mass per area and increased foliar phosphorus, three plant traits related to light capture and growth. Carbon declines amplified with edge age. Our results indicate that carbon losses along forest edges can arise from multiple, distinct effects on canopy structure and function that vary with edge age and environmental conditions, pointing to a need for consideration of differences in ecosystem sensitivity when developing land-use and conservation strategies. Our findings reveal that, although edge effects on ecosystem structure and function vary, forests neighboring agricultural plantations are consistently vulnerable to long-lasting negative effects on fundamental ecosystem characteristics controlling primary productivity and carbon storage.


Assuntos
Carbono/metabolismo , Conservação dos Recursos Naturais , Ecossistema , Clima Tropical , Agricultura/tendências , Biomassa , Bornéu , Florestas , Fósforo/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Árvores
17.
Ecotoxicol Environ Saf ; 193: 110355, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32120164

RESUMO

In the Montado system, in Portuguese Alentejo region, some Eutric Cambisols are known to promote manganese (Mn) toxicity in wheat. Variation on bioavailable Mn concentration depends on soil acidity, which can be increased by natural events (e.g. waterlogging) or human activity (e.g. excess use of chemical fertilizers). The effect of increasing soil Mn on crop element uptake, element distribution and oxidative stress was evaluated on winter wheat (Triticum aestivum). Plants were grown for 3 weeks in an acidic Cambisol spiked with increasing Mn concentrations (0, 45.2 and 90.4 mg MnCl2/Kg soil). Calcium (Ca), phosphorus (P), magnesium (Mg) and Mn were quantified in the soil solution, root and shoot tissues and respective subcellular fractions. The activity of the antioxidant enzymes ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), guaiacol peroxidase (GPX) and superoxide dismutase (SOD) were determined in extracts of wheat shoots and roots. Overall, increase in soil bioavailable Mn inhibited the uptake of other elements, increased the Ca proportion in the root apoplast, promoted the translocation of Mn and P to shoot tissues and increased their proportion in the shoot vacuoles. Wheat roots showed greater antioxidant enzymes activities than shoots. These activities decreased at the highest soil Mn concentration in both plant parts. Wheat roots appear to be more sensitive to oxidative stress derived from excess soil Mn and promote Mn translocation and storage in shoot vacuoles, probably in Mn and P complexes, as a detoxification strategy. Improvement in wheat production, in acidic soils, may rely on the enhancement of its Mn detoxification strategies.


Assuntos
Manganês/toxicidade , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Transporte Biológico , Cálcio/metabolismo , Catalase/metabolismo , Glutationa Redutase/metabolismo , Magnésio/metabolismo , Manganês/farmacocinética , Estresse Oxidativo , Peroxidase/metabolismo , Fósforo/metabolismo , Solo/química , Poluentes do Solo/farmacocinética , Superóxido Dismutase/metabolismo , Triticum/enzimologia , Triticum/metabolismo
18.
Nat Commun ; 11(1): 1500, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198372

RESUMO

Anthropogenic nutrient discharge to coastal marine environments is commonly associated with excessive algal growth and ecosystem degradation. However in the world's largest coral reef ecosystem, the Great Barrier Reef (GBR), the response to enhanced terrestrial nutrient inputs since European settlement in the 1850's remains unclear. Here we use a 333 year old composite record (1680-2012) of 15N/14N in coral skeleton-bound organic matter to understand how nitrogen cycling in the coastal GBR has responded to increased anthropogenic nutrient inputs. Our major robust finding is that the coral record shows a long-term decline in skeletal 15N/14N towards the present. We argue that this decline is evidence for increased coastal nitrogen fixation rather than a direct reflection of anthropogenic nitrogen inputs. Reducing phosphorus discharge and availability would short-circuit the nitrogen fixation feedback loop and help avoid future acute and chronic eutrophication in the coastal GBR.


Assuntos
Antozoários/fisiologia , Ciclo do Nitrogênio , Nitrogênio/metabolismo , Animais , Recifes de Corais , Ecossistema , Monitoramento Ambiental , Eutrofização , Isótopos , Biologia Marinha , Fósforo/metabolismo
19.
Plant Biol (Stuttg) ; 22(4): 615-622, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32160384

RESUMO

Phosphorus (P) is an important nutrient that can restrict plant growth. However, the influence of P deficiency on elemental homeostasis and application of the growth rate hypothesis in higher plants remain to be assessed. Two shrubs, Zygophyllum xanthoxylum and Nitraria tangutorum, were used as experiment material and subjected to five P addition treatments: 0, 17.5, 35.0, 52.5 and 70.0 mg P·kg-1 soil. The biomass and relative growth rate of Z. xanthoxylum did not change with altered P supply. There was no significant difference in P concentration among the treatments for Z. xanthoxylum, but N. tangutorum showed an upward trend. The P stoichiometric homeostasis of Z. xanthoxylum was higher than that of N. tangutorum. For Z. xanthoxylum, available P in the rhizosphere improved significantly under extreme P deficiency conditions, and P concentrations in all treatments were lower than in N. tangutorum, showing that Z. xanthoxylum had stronger P absorption and P utilization capacity. No relationships between growth rate and C:N:P ratios were found in Z. xanthoxylum. The strong P efficiency, and high and stable dry matter accumulation, are likely contributors in maintaining stoichiometric homeostasis. In addition, the relatively high biomass accumulation and high P utilization efficiency for Z. xanthoxylum does not support the growth rate hypothesis for this species.


Assuntos
Magnoliopsida , Fósforo , Zygophyllum , Biomassa , Magnoliopsida/metabolismo , Fósforo/metabolismo , Rizosfera , Solo/química , Zygophyllum/crescimento & desenvolvimento , Zygophyllum/metabolismo
20.
Chemistry ; 26(26): 5903-5910, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32142179

RESUMO

First-in-class CuII and AuIII metaled phosphorus dendrons were synthesized and showed significant antiproliferative activity against several aggressive breast cancer cell lines. The data suggest that the cytotoxicity increases with reducing length of the alkyl chains, whereas the replacement of CuII with AuIII considerably increases the antiproliferative activity of metaled phosphorus dendrons. Very interestingly, we found that the cell death pathway is related to the nature of the metal complexed by the plain dendrons. CuII metaled dendrons showed a potent caspase-independent cell death pathway, whereas AuIII metaled dendrons displayed a caspase-dependent apoptotic pathway. The complexation of plain dendrons with AuIII increased the cellular lethality versus dendrons with CuII and promoted the translocation of Bax into the mitochondria and the release of Cytochrome C (Cyto C).


Assuntos
Citocromos c/metabolismo , Dendrímeros/metabolismo , Metais/química , Mitocôndrias/química , Fósforo/química , Apoptose , Morte Celular , Citocromos c/química , Dendrímeros/química , Humanos , Células MCF-7 , Metais/metabolismo , Mitocôndrias/metabolismo , Estrutura Molecular , Fósforo/metabolismo
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