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1.
Mol Plant ; 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34619329

RESUMO

Agricultural soils are under threat of toxic metal/metalloid contamination from anthropogenic activities, leading to excessive accumulation of arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in food crops that poses significant risks to human health. Understanding how these toxic metals and their methylated species are taken up, translocated and detoxified is prerequisite to developing strategies to limit their accumulation for safer food. Toxic metals are taken up and transported across different cellular compartments and plant tissues via transporters for essential or beneficial nutrients, e.g. As by phosphate and silicon transporters, and Cd by manganese (Mn), zinc (Zn) and iron (Fe) transporters. These transport processes are subjected to interactions with nutrients and regulations at the transcription and post-translation levels. Complexation with thiol-rich compounds such as phytochelatins and sequestration in the vacuoles are the common mechanisms for detoxification and for limiting their translocation. A number of genes involved in toxic metal uptake, transport and detoxification have been identified, offering targets for manipulations via gene editing or transgenic technologies. Natural variations in toxic metal accumulation exist within crop germplasm, and some of the quantitative trait loci underlying these variations have been cloned, paving the way for marker-assisted breeding of low metal accumulation crops. Using plants to extract and remove toxic metals from soil is also possible, but this phytoremediation approach requires metal hyperaccumulation for efficiency. Knowledge gaps and future research needs are also discussed.

2.
Environ Microbiol ; 2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34676971

RESUMO

Toxic organoarsenicals enter the environment from biogenic and anthropogenic activities such as microbial methylation of inorganic arsenic and pentavalent herbicides such as monosodium methylarsenate (MSMA or MAs(V)). Trivalent MAs(III) is considerably more toxic than arsenite or arsenate. Microbes have evolved mechanisms to detoxify organoarsenicals. We previously identified ArsV, a flavin-linked monooxygenase and demonstrated that it confers resistance to methylarsenite by oxidation to methylarsenate. The arsV gene is usually in an arsenic resistance (ars) operon controlled by an ArsR repressor and adjacent to a methylarsenite efflux gene, either arsK or a gene for a putative transporter. Here we show that Paracoccus sp. SY oxidizes methylarsenite. It has an ars operon with three genes, arsR, arsV and a transport gene termed arsW. Heterologous expression of arsV in Escherichia coli conferred resistance to MAs(III), while arsW did not. Co-expression of arsV and arsW increased resistance compared with either alone. The cells oxidized methylarsenite and accumulated less methylarsenate. Everted membrane vesicles from E. coli cells expressing arsW-accumulated methylarsenate. We propose that ArsV is a monooxygenase that oxidizes methylarsenite to methylarsenate, which is extruded by ArsW, one of only a few known pentavalent organoarsenical efflux permeases, a novel pathway of organoarsenical resistance.

3.
Age Ageing ; 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34510170

RESUMO

BACKGROUND: Globally, geriatric patients are the dominant population requiring global medical care. We established a frailty index for geriatric trauma patients by retrospectively analysing electronic hospital records to identify patients with frailty characteristics and poor prognostic outcomes. METHOD: Data were obtained from 2016 US National Emergency Department Sample and Shanghai Trauma Emergency Medical Association (2015-18). Overall, 141,267 hospitalised geriatric trauma patients (age ≥ 65 years) were included. We used a three-step method to construct geriatric trauma frailty index (GTFI) based on the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnostic codes. Systematic cluster analysis was used. The accuracy of GTFI was verified in national validation cohort, and its applicability to Chinese patients was assessed in local validation cohort. RESULTS: In development cohort (n = 28,179), frail patients had longer lengths of stay and higher Charlson co-morbidity index than non-frail patients (18.2 ± 12.4 days, 5.59 ± 2.0 versus 5.3 ± 5.3 days, 5.33 ± 1.8, respectively). In national validation cohort (n = 113,089), frail patients had longer lengths of stay (8.5 ± 8.8 days versus 4.5 ± 3.1 days) and higher in-hospital mortality than non-frail patients (2,795, 11.69% versus 589, 0.66%). Areas under the curves for GTFI for length of stay (>14 days) and in-hospital mortality were 0.848 (0.841, 0.854) and 0.885 (0.880, 0.891) in national validation cohort, and were 0.791 (0.779, 0.804) and 0.903 (0.885, 0.922) in local validation cohort (n = 14,827). CONCLUSIONS: The GTFI helps hospitals and emergency departments to identify geriatric trauma patients with poor prognostic outcomes, and has been proven to be useful in China.

4.
Environ Pollut ; 289: 117918, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34426194

RESUMO

Representing the staple crop for half of the world population, rice can accumulate high levels of cadmium (Cd) in its grain, posing concerns on food safety. Different soil amendments have been proposed to decrease Cd accumulation in rice grain by either decreasing soil Cd availability, introducing competitive ions on Cd uptake, or down-regulating the expression of transporters for Cd uptake. However, the effectiveness of soil amendments applied alone or in combinations needs to be tested under field conditions. Here, we present results of field trials with two rice cultivars differing in Cd accumulation grown at three field sites in southern China in two years, to investigate the effects of two Mn-containing soil amendments (MnO2, Mn-loaded biochar (MB)), Si fertilizer (Si), limestone, and K2SO4, as well as interactions among MnO2, Si, and limestone on decreasing Cd accumulation in rice grain. We found that single applications of MnO2 or MB to acidic soils low in Mn decreased grain Cd concentrations by 44-53 % or 78-82 %, respectively, over two years without decrease in performance. These effects were comparable to or greater than those induced by limestone liming alone (45-62 %). Strong interactions between MnO2 and limestone resulting from their influence on soil extractable Cd and Mn led to non-additive effects on lowering grain Cd. MB addition minimized grain Cd concentrations, primarily by increasing extractable and dissolved Mn concentrations, but also by decreasing Cd extractability in soil. In comparison, Si and K2SO4 amendments affected grain Cd levels only weakly. We conclude that the amendments that decrease labile Cd and increase labile Mn in soils are most effective at reducing Cd accumulation in rice grain, thus contributing to food safety.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Compostos de Manganês , Óxidos , Solo , Poluentes do Solo/análise
5.
Nutrients ; 13(7)2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-34371952

RESUMO

The distinct Tibetan regional diet is strongly influenced by the regional biogeography, indigenous traditions, popular religious beliefs and food taboos. In the context of the nutritional transition in Tibet, studies seldom report on the food consumption and dietary patterns of Tibetan residents. This is a cross-section study of 552 local adults (≥18 years old, 277 men and 275 women) living in 14 agricultural countries along the Yarlung Tsangpo River. Dietary intakes were assessed by a culturally specific FFQ and compared with the Chinese Dietary Pagoda (2016). Dietary Patterns were extracted by using PCA method. The binary logistic regression model was applied to assess the association between independent variables (genders, regions and age groups) and adherence to dietary patterns. With the exception of meat (100 ± 260 g/day) and soybean nuts (42 ± 12 g/day), which exceeded the recommended dietary intakes of CDP, the dietary intake of other foods were not up to the recommended value. In particular, the intake of aquatic products (2 ± 0.1 g/day), vegetables (90 ± 19 g/day), dairy products (114 ± 29 g/day), cereals (117 ± 27 g/day) and fruits (97 ± 25 g/day) were seriously inadequate, which were 95%, 70%, 62%, 53.2% and 51.5% lower than the recommended intakes, respectively. Four dietary patterns were identified. "Local traditional diet" was characterized by a high intake of tsampa (roasted highland barley flour), culturally specific beverages (sweet tea and yak buttered tea), potato and yak beef and was associated with female, rural and older adults (≥51 years old). The male, urban and 18~30 years old group had a higher adherence score with the "Han diet", which was comprised of rice, pork, dumplings, eggs, milk and cabbage. The "Beverage diet", which mainly include tsampa, chang (homemade barley wine) and sweet tea, was associated with the following group: female, urban and aged 18~30 years. The "Out-sourced diet" pattern, consisting of mainly rice, steam bread and some processed meat, was associated with being male, urban and 18-30 years of age. These findings indicate that the dietary practice of the Tibetan people still has strong local characteristics, but it is also undergoing a dietary transition with the penetration of the Chinese Han diet and the increased consumption of outsourced (processed) foods. The unbalanced dietary intake of Tibetan residents should be taken seriously by all parties.


Assuntos
Dieta , Comportamento Alimentar , Adolescente , Adulto , Fatores Etários , Bebidas , Estudos Transversais , Inquéritos sobre Dietas , Ingestão de Alimentos , Feminino , Frutas , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Recomendações Nutricionais , Rios , População Rural , Fatores Sexuais , Tibet , População Urbana , Verduras , Adulto Jovem
6.
Environ Sci Technol ; 55(14): 9845-9853, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34191485

RESUMO

Most of the cadmium (Cd) accumulated in rice grains is derived from its remobilization in soils during the grain filling period when paddy water is drained. The factors affecting Cd remobilization upon drainage remain poorly understood. Here, we show that the free radical effect produced from the oxidation of ferrous sulfides is an important mechanism affecting the oxidative remobilization of Cd during soil drainage. When soils were flooded, microbial sulfate reduction results in the formation of various metal sulfides including CdS and FeS. Upon soil drainage, the oxidation of FeS produced considerable amounts of hydroxyl free radicals (OH•), which could oxidize CdS directly and thereby promote the oxidative dissolution of CdS and increase Cd mobilization in soils. FeS and CdS could also form a within-sulfide voltaic cell, with FeS protecting the oxidative dissolution of CdS due to the lower electrochemical potential of the former. However, this voltaic effect was short-lived and was surpassed by the free radical effect. The amounts and composition of metal sulfides formed during soil flooding vary with soils, and the oxidative dissolution of CdS is affected by both the free radical and voltaic effects offered by different metal sulfides. These effects are also applicable to the biogeochemistry of other chalcophile trace elements coupled with sulfur and iron redox cycles during the anoxic-oxic transition in many environments.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Radicais Livres , Oxirredução , Solo , Poluentes do Solo/análise , Sulfetos
7.
Environ Sci Technol ; 55(13): 8665-8674, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34110124

RESUMO

Arsenic species transformation in paddy soils has important implications for arsenic accumulation in rice grains and its safety to the consumers. Methylated thioarsenates including highly toxic dimethylated monothioarsenate (DMMTA) have been detected in paddy soils, but their production and dynamics remain poorly understood. In the present study, we first optimized a HPLC-ICP-MS method to quantify methylated thioarsenate species. Using this method together with 10 mM diethylenetriamine pentaacetate (DTPA) to preserve As speciation, we investigated methylated thioarsenate species in porewaters of seven As-contaminated soils incubated under flooded conditions and of two paddy fields. DMMTA was the main methylated thioarsenate species in the porewaters in both incubated soils and paddy fields, with concentrations ranging from 0.2 to 36.2 µg/L and representing ca. 58% of its precursor dimethylarsenate (DMA). The temporal production and dynamics of DMMTA were linked with the DMA concentrations. When soils were drained, DMMTA was converted to DMA. In the two paddy fields, DMMTA concentrations in rice grains were 0.4-10.1 µg/kg. Addition of sulfur fertilizer and rice straw incorporation increased grain DMMTA by 9-28%. These results suggest that DMMTA is an important As species in paddy soils and can accumulate in rice grains, presenting a risk to food safety and human health.


Assuntos
Arsênio , Oryza , Poluentes do Solo , Ácido Cacodílico , Humanos , Solo , Poluentes do Solo/análise
8.
Proc Natl Acad Sci U S A ; 118(13)2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33771925

RESUMO

Polyploidy is a prominent feature for genome evolution in many animals and all flowering plants. Plant polyploids often show enhanced fitness in diverse and extreme environments, but the molecular basis for this remains elusive. Soil salinity presents challenges for many plants including agricultural crops. Here we report that salt tolerance is enhanced in tetraploid rice through lower sodium uptake and correlates with epigenetic regulation of jasmonic acid (JA)-related genes. Polyploidy induces DNA hypomethylation and potentiates genomic loci coexistent with many stress-responsive genes, which are generally associated with proximal transposable elements (TEs). Under salt stress, the stress-responsive genes including those in the JA pathway are more rapidly induced and expressed at higher levels in tetraploid than in diploid rice, which is concurrent with increased jasmonoyl isoleucine (JA-Ile) content and JA signaling to confer stress tolerance. After stress, elevated expression of stress-responsive genes in tetraploid rice can induce hypermethylation and suppression of the TEs adjacent to stress-responsive genes. These induced responses are reproducible in a recurring round of salt stress and shared between two japonica tetraploid rice lines. The data collectively suggest a feedback relationship between polyploidy-induced hypomethylation in rapid and strong stress response and stress-induced hypermethylation to repress proximal TEs and/or TE-associated stress-responsive genes. This feedback regulation may provide a molecular basis for selection to enhance adaptation of polyploid plants and crops during evolution and domestication.

9.
Environ Microbiol ; 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33769668

RESUMO

Arsenic can be biomethylated to form a variety of organic arsenicals differing in toxicity and environmental mobility. Trivalent methylarsenite (MAs(III)) produced in the methylation process is more toxic than inorganic arsenite (As(III)). MAs(III) also serves as a primitive antibiotic and, consequently, some environmental microorganisms have evolved mechanisms to detoxify MAs(III). However, the mechanisms of MAs(III) detoxification are not well understood. In this study, we identified an arsenic resistance (ars) operon consisting of three genes, arsRVK, that contribute to MAs(III) resistance in Ensifer adhaerens ST2. ArsV is annotated as an NADPH-dependent flavin monooxygenase with unknown function. Expression of arsV in the arsenic hypersensitive Escherichia coli strain AW3110Δars conferred resistance to MAs(III) and the ability to oxidize MAs(III) to MAs(V). In the presence of NADPH and either FAD or FMN, purified ArsV protein was able to oxidize both MAs(III) to MAs(V) and Sb(III) to Sb(V). Genes with arsV-like sequences are widely present in soils and environmental bacteria. Metagenomic analysis of five paddy soils showed the abundance of arsV-like sequences of 0.12-0.25 ppm. These results demonstrate that ArsV is a novel enzyme for the detoxification of MAs(III) and Sb(III) and the genes encoding ArsV are widely present in soil bacteria.

10.
Nat Commun ; 12(1): 1392, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33654102

RESUMO

Rice grains typically contain high levels of toxic arsenic but low levels of the essential micronutrient selenium. Anthropogenic arsenic contamination of paddy soils exacerbates arsenic toxicity in rice crops resulting in substantial yield losses. Here, we report the identification of the gain-of-function arsenite tolerant 1 (astol1) mutant of rice that benefits from enhanced sulfur and selenium assimilation, arsenic tolerance, and decreased arsenic accumulation in grains. The astol1 mutation promotes the physical interaction of the chloroplast-localized O-acetylserine (thiol) lyase protein with its interaction partner serine-acetyltransferase in the cysteine synthase complex. Activation of the serine-acetyltransferase in this complex promotes the uptake of sulfate and selenium and enhances the production of cysteine, glutathione, and phytochelatins, resulting in increased tolerance and decreased translocation of arsenic to grains. Our findings uncover the pivotal sensing-function of the cysteine synthase complex in plastids for optimizing stress resilience and grain quality by regulating a fundamental macronutrient assimilation pathway.


Assuntos
Arsênio/metabolismo , Oryza/metabolismo , Sementes/metabolismo , Selênio/metabolismo , Enxofre/metabolismo , Alelos , Cloroplastos/metabolismo , Cisteína Sintase/metabolismo , Redes e Vias Metabólicas , Modelos Biológicos , Mutação/genética , Fenótipo , Fitoquelatinas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Serina/metabolismo , Frações Subcelulares/metabolismo
11.
Front Genet ; 12: 638555, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33569081

RESUMO

Rice provides more than one fifth of daily calories for half of the world's human population, and is a major dietary source of both essential mineral nutrients and toxic elements. Rice grains are generally poor in some essential nutrients but may contain unsafe levels of some toxic elements under certain conditions. Identification of quantitative trait loci (QTLs) controlling the concentrations of mineral nutrients and toxic trace metals (the ionome) in rice will facilitate development of nutritionally improved rice varieties. However, QTL analyses have traditionally considered each element separately without considering their interrelatedness. In this study, we performed principal component analysis (PCA) and multivariate QTL analyses to identify the genetic loci controlling the covariance among mineral elements in the rice ionome. We resequenced the whole genomes of a rice recombinant inbred line (RIL) population, and performed univariate and multivariate QTL analyses for the concentrations of 16 elements in grains, shoots and roots of the RIL population grown in different conditions. We identified a total of 167 unique elemental QTLs based on analyses of individual elemental concentrations as separate traits, 53 QTLs controlling covariance among elemental concentrations within a single environment/tissue (PC-QTLs), and 152 QTLs which determined covariation among elements across environments/tissues (aPC-QTLs). The candidate genes underlying the QTL clusters with elemental QTLs, PC-QTLs and aPC-QTLs co-localized were identified, including OsHMA4 and OsNRAMP5. The identification of both elemental QTLs and PC QTLs will facilitate the cloning of underlying causal genes and the dissection of the complex regulation of the ionome in rice.

12.
Mil Med ; 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33410886

RESUMO

INTRODUCTION: To assess the self-perceived mental health of soldiers and officers in the submarine force in the South China Sea, the result of this investigation was compared to the Chinese military male norms, and the factors that influence their mental health was further explored. MATERIALS AND METHODS: A total of 580 male submariners agreed to participate. In the final analysis, 511 valid questionnaires were included; 69 incomplete questionnaires were excluded. The Symptom Checklist 90 (SCL-90) was used to measure the self-perceived mental health of the officers and soldiers. RESULTS: The scores of four dimensions (somatization, anxiety, phobic anxiety, and paranoid ideation) and the average of the total SCL-90 scores for the submarine force in the South China Sea were significantly higher than the Chinese military norms. Age and length of service were found to be protective factors, with 26- to 30-year-old age group (adjusted odds ratio [AOR] = 0.365, 95% CI = 0.138-0.961) and individuals with 6 to 10 years of service (AOR = 0.357, 95% CI = 0.151-0.842) having lower odds of poor mental health. Education level (bachelor's degree) and workplace (nuclear submarine) were found to be risk factors. CONCLUSIONS: This study demonstrates for the first time that soldiers and officers in the submarine force in the South China Sea are exposed to a number of mental health risks and are suffering from serious psychological problems. These findings provide a basis for military departments to effectively address these psychological problems.

13.
Environ Sci Technol ; 55(3): 1576-1584, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33423475

RESUMO

Chromate (Cr[VI]) is a highly phytotoxic contaminant that is ubiquitous in soils. However, how Cr(VI) is taken up by plant roots remains largely unknown. Here, we show that the high-affinity sulfate transporter Sultr1;2 is responsible for Cr(VI) uptake by the roots of Arabidopsis thaliana. Sultr1;2 showed a much higher transport activity for Cr(VI) than Sultr1;1 when expressed in yeast cells. Knockdown of Sultr1;2 expression in Arabidopsis markedly reduced the Cr(VI) uptake rate, whereas knockout of Sultr1;1 had no or little effect. A double-knockout mutant (DKO) of the two genes lost the ability of Cr(VI) uptake almost completely. The Sultr1;2 knockdown mutant or DKO plants displayed higher resistance to Cr(VI) under normal sulfate conditions as a consequence of the lower tissue Cr accumulation. Overexpression of Sultr1;2 substantially increased Cr(VI) uptake with shoot Cr concentration being 1.6-2.0 times higher than that in the wild-type. These results indicate that Sultr1;2 is a major transporter responsible for Cr(VI) uptake in Arabidopsis, while Sultr1;1 plays a negligible role. Taken together, our study has identified a major transporter for Cr(VI) uptake in plants, providing potential strategies for engineering plants with low Cr accumulation and consequently enhanced Cr(VI) resistance and also plants with enhanced accumulation of Cr for the purpose of phytoremediation.


Assuntos
Proteínas de Arabidopsis , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cromo , Regulação da Expressão Gênica de Plantas , Raízes de Plantas/metabolismo , Transportadores de Sulfato , Enxofre/metabolismo
14.
Environ Sci Technol ; 55(3): 1750-1758, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33492945

RESUMO

Excessive cadmium (Cd) accumulation in rice grain is a global issue that affects human health. The drainage of paddy soils during the grain filling period leads to the remobilization of Cd in soils, resulting in most of the Cd accumulated in rice grain. The rate of Cd remobilization during drainage differs markedly among soils, but the mechanisms underlying these differences remain largely unknown. Using microcosm soil incubation, electrochemical experiments, isotope labeling, and microscopic and spectroscopic analyses, here, we discover the voltaic effect as a novel mechanism controlling the remobilization of Cd during soil drainage. During soil flooding, microbial sulfate reduction results in the formation of various metal sulfides. When the soils are subsequently drained, the various metal sulfides can form within sulfide voltaic cells. The metal sulfides with a lower electrochemical potential act as anodes and are prone to oxidative dissolution, whereas the metal sulfides with a higher potential act as cathodes and are protected from oxidation. This voltaic effect explains why the presence of ZnS (with a low potential) suppresses the oxidative dissolution of Cd sulfides, whereas the presence of CuS (with a high potential) promotes the oxidative dissolution of Cd sulfides. The voltaic effect is applicable to all chalcophile trace metals coupled with the sulfur redox cycle in periodically anoxic-oxic environments, thus playing an important role in the biogeochemistry of trace metals.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Humanos , Oxirredução , Solo , Poluentes do Solo/análise
15.
Plant Dis ; 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441010

RESUMO

American ginseng (Panax quinquefolium L.) originating from North America is one of important herbal medicine and economic crops . With the increasing market demand, China has become the third producer and the largest consumer country of American ginseng. However, continuous cropping obstacle has become the most serious problem for the production of American ginseng, and the continuous cropping of soils usually lead to accumulations of root fungal pathogens and increasing plant disease occurrence (1), root rot caused by the notorious soil-borne pathogenic fungi, Fusarium spp., results in a significant reduction of yield and quality of American ginseng. Investigation of American ginseng root rot was carried out in Liuba county, Shaanxi province, China from 2017 to 2019. About 20% of over 3-year-old American ginseng showed varied root rot symptoms in newly reclaimed fields, and more than 70% in continuous American ginseng planting fields. Among these root rot diseases, we found one kind of disease which shows symptoms of red leaves in initial stage and yellow or yellow brown lesions at the reed heads or taproots. The lesions mainly appear on the root surface; however, the vascular tissue has no discoloration. The aboveground parts become wilted and died, and the whole root appears dark brown rots. Fifteen Fusarium spp. isolates were obtained by cutting diseased rot roots into 5 × 5 mm2 pieces, disinfecting in 70% ethanol for 1 min, rinsing 2 ~ 3 times in sterile water for 1 min and isolating on PDA medium including 50 µg/mL streptomycin sulfate. All the isolates have identical morphological characteristics. The colony was white with curved and uplifted aerial hyphae in central region. The colony diameter was 48 ~51 mm after 6 days at room temperature. Microconidia were oval to cylindrical shape with 0 to 1 septa, ranged from 6.24 to10.09 µm long; the macroconidia were fusiform to conical with a hooked apical cell and a foot-shaped basal cell, usually 3 to 5 septa, ranged from 31.45 to 42.52 µm long. The chlamydospores were not found under our culture condition. Preliminary data analysis showed that the morphological characteristics of these isolates were consistent with the descriptions of Fusarium redolens (2). To clarify the fungus in the taxonomy , the rDNA internal transcribed spacer (ITS), the translation elongation factor 1 alpha (TEF1-α) and the RNA polymerase II subunit 1 (RPB1) fragments of two randomly selected isolates were amplified and sequenced. The sequences of the corresponding fragments of the two isolates were identical. The blast results in the GenBank and FUSARIUM-ID databases show the isolates belong to F. redolens (3). Previous study indicated F. redolens has an indistinguishable relative, F. hostae (4). Although the ITS sequence (MW331695) cannot provide enough information to distinguish them, the phylogenetic tree combined the sequence of TEF1-α (tempID: 2407237 ) and RPB1 (tempID: 2407229) clearly showed that the isolates are F. redolens. (Fig) The pathogenicity of a representative isolate, YP04, was tested on ginseng taproot by in vivo inoculation experiments with three replications. The taproot surface of 2-year-old healthy ginseng was washed and disinfested with 75% alcohol for 1 min and rinsed with sterile water, and dried. The surface of taproot was injured with sterilized steel needles and immersed in 1 × 106 /ml spore suspension (sterile water for control plants) for 30 min. The treatment and control plants were transplanted in 20 cm diameter flowerpots filled with sterilized humus and cultured in a greenhouse at 18-23°C. Six days after transplanting, the leaves began to turn red. The cortex of ginseng taproot showed yellow brown lesions and the vascular tissue turn to light yellow. Fifteen days after transplanting, the aboveground parts of treatment plants began to wilting and the taproots showed serious rots. no taproot rot was observed in the controls. The pathogen was re-isolated from the diseased taproots successfully. To our knowledge, this is the first report of F. redolens causing root rot of American ginseng in China.

16.
Sci Total Environ ; 761: 143262, 2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33218811

RESUMO

Consumption of rice (Oryza sativa) grain is a major pathway by which humans are exposed to Cd, especially in non-smoking Asian populations. Although the stable isotope signatures of Cd offer a potential tool for tracing its sources, little is known about the isotopic fractionation of Cd across the entire soil-rice-human continuum. Cadmium isotope ratios were determined in field soils, rice grain, and human urine collected from two Cd-contaminated regions in southern China. Additionally, Cd isotopic fractionation in rice plants was investigated using two transgenic plants differing in Cd uptake and accumulation. Analysis of isotope ratios revealed a preferential enrichment of the heavy Cd isotopes from soil to rice grain (δ114/110Cdgrain-soil = +0.40‰) and from grain to urine (δ114/110Cdurine-grain = +0.40‰) in both regions. The first increase was mainly caused by partitioning between the soil solid phase and the soil solution, with heavier Cd preferentially enriching in the soil solution. Within the rice plant, we identified multiple processes that alter the isotope ratio, but the net effect throughout the plant was comparatively small. Cd fractionation in humans is presumably due to the preferential enrichment of heavier Cd isotopes by metal transporters DMT1 and ZIP8 (responsible for the absorption of Cd into body from the foods). These findings provide important insights into the Cd isotopic fractionation through the soil-rice-human continuum and are helpful for tracing the sources of Cd.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , China , Humanos , Isótopos , Solo , Poluentes do Solo/análise
17.
Psychol Health Med ; 26(2): 184-195, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32156163

RESUMO

Background: Yushu, Qinghai province is located in remote Tibetan plateau in Western China, struck by a disastrous earthquake in 2010. The study aimed to find out the positive and negative psychological changes and related risk factors of children and adolescents who had experienced Yushu earthquake, 6 years after it occurred. Methods: A cross-sectional research was adopted in the capital of Yushu Autonomous Prefecture in August 2016. The short form of the Changes in Outlook Questionnaire (CiOQ-S) was used, which is a 10-item self-report instrument consists of two subscales. A total of 591 valid questionnaires completed by local junior students were finally included in our study. Results: The mean scores of the positive and negative psychological changes were 19.28 and 13.08, respectively. The factors associated with positive psychological changes included high level of education, male gender, and uninjured in the earthquake. The factors associated with negative psychological changes included living in a pasture instead of downtown, injured during the earthquake, and not receiving psychological counselling. Conclusions: The current analysis tries to investigate the long-term psychological effects of earthquakes among children and adolescents, which aims to improve the psychological health status for child and adolescent survivors of similar events.

18.
Environ Pollut ; 268(Pt B): 115944, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33160733

RESUMO

Cadmium bioavailability in paddy soils is strongly affected by flooding-draining cycle. In this study, we used synchrotron-based X-ray absorption spectroscopy and a stirred-flow method to investigate the effects of flooding-draining and amendments of CaCO3 and CaSO4 on Cd speciation and release kinetics from a Cd-spiked paddy soil (total Cd concentration of 165 mg kg-1). Extended X-ray absorption fine structure analysis showed that Cd was predominantly bound to non-iron-clay minerals (e.g. Cd-kaolinite, Cd-illite, and Cd-montmorillonite, accounting for 60-100%) in the air-dried soil and 1- or 7-day flooded samples. After prolonged flooding (30 and 120 days), Cd-iron mineral complexes (e.g. Cd bound to ferrihydrite and goethite) became the predominant species (accounting for 52-100%). Stirred-flow kinetic analysis showed that both prolonged flooding and the amendments with CaCO3 and CaSO4 decreased the maximum amount and the rate coefficient of Cd release. However, the effect of prolonged flooding was reversed after a short period of draining, indicating that although Cd was immobilized during flooding, it became mobile rapidly after the soil was drained, possibly due to pH decrease and rapid oxidation of CdS. The effects of the amendments on Cd uptake in rice plants were tested in a pot experiment using the same paddy soil without Cd spiking (total Cd 2.1 mg kg-1). Amendment with CaCO3 and, to a lesser extent, CaSO4, decreased the Cd accumulation in two cultivars of rice. The combination of CaCO3 amendment and a low Cd accumulating cultivar was effective at limiting grain Cd concentration to below the 0.2 mg kg-1 limit.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Cinética , Solo , Poluentes do Solo/análise
19.
Sci Total Environ ; 758: 143596, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33243504

RESUMO

Cadmium (Cd) contamination in agricultural soils is a widespread environmental problem that can affect food safety and human health. Effective remediation methods are needed to reduce Cd bioavailability in soil and Cd accumulation in food crops. In the present study, we isolated a Cd-resistant and alkalizing bacterium strain XT-4 from a Cd-contaminated soil and evaluated its potential application in Cd bioremediation. Based on its morphological, physiological and biochemical characteristics, together with 16S rRNA gene sequence analysis, strain XT-4 was identified as a member of the Bacillus genus. Strain XT-4 showed a strong ability to increase the pH and decrease Cd solubility in the medium. A greenhouse-based pot experiment with a Cd-contaminated soil was conducted to evaluate the effect of strain XT-4 inoculation on the growth and Cd accumulation of the vegetable Pak choi (Brassica rapa ssp. chinensis). Inoculation increased the rhizosphere pH, decreased CaCl2-extractable Cd in the soil and decreased Cd concentration in the edible part of Pak choi by 28-40%. The results suggest that inoculation with alkalizing bacterial strain XT-4 represents an effective solution to increase rhizosphere pH and decrease Cd uptake by vegetable crops in Cd-contaminated acid soils.


Assuntos
Cádmio , Poluentes do Solo , Disponibilidade Biológica , Cádmio/análise , Humanos , RNA Ribossômico 16S/genética , Solo , Poluentes do Solo/análise , Verduras
20.
Chemosphere ; 267: 128893, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33176911

RESUMO

Rice grains produced on cadmium (Cd) contaminated paddy soils often exceed the maximum permissible limit. A number of mitigation methods have been proposed to decrease Cd accumulation in rice grain in contaminated acidic soils, including altering water management regimes, liming, and genetic engineering. In the present study, we conducted a pot experiment to compare these methods for their effectiveness at decreasing grain Cd concentrations in both acidic (pH 5.1-5.2) and alkaline (pH 7.5-7.9) paddy soils that varied in the degree of Cd contamination. In moderately Cd-contaminated acidic soils (with Cd concentrations lower than the intervention value of Chinese soil standard, GB15618-2018), any of the three methods was effective, reducing grain Cd concentration by 80-90% to levels below the Chinese maximum permissible limit (0.2 mg/kg). However, in the highly Cd-contaminated soils (with soil Cd concentrations exceeding the intervention value) with elevated concentrations of extractable Cd, although both liming and alternation of the water management regime (continuous flooding) was effective at decreasing grain Cd accumulation, grain Cd concentrations still exceeded the Chinese limit. Genetic engineering of rice, such as knockout of OsNramp5 (encoding the plasma membrane transporter responsible for Cd uptake into root cells) or overexpression of OsHMA3 (encoding a tonoplast Cd transporter sequestering Cd into the vacuoles), produced dramatic decreases (≥90%) in grain Cd concentration. Even in seriously contaminated soils, overexpression of OsHMA3 alone produced grain with Cd concentrations below the Chinese limit, offering a highly effective approach to produce Cd-safe rice especially in seriously Cd-contaminated paddy soils without affecting grain biomass or the concentrations of essential micronutrients.


Assuntos
Oryza , Poluentes do Solo , Cádmio/análise , Grão Comestível/química , Solo , Poluentes do Solo/análise
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