Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 342
Filtrar
Filtros adicionais











País/Região como assunto
Intervalo de ano
1.
Environ Pollut ; 254(Pt A): 113016, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31400666

RESUMO

Dissolved organic carbon (DOC) has a major influence upon sorption/desorption and transport of hydrophobic organic contaminants (HOCs) in soil environments. However, the molecular mechanisms of DOC sorption and its effects on aged HOC desorption in contaminated soils still remain largely unclear. Here, effects of three different DOC (one from commercial peat and two from biochars produced at 300 °C and 500 °C pyrolysis temperatures, respectively) and oxalate (as a reference) on abiotic desorption behavior of aged phenanthrene from three agricultural soils were investigated. Results showed that desorption of aged phenanthrene from soils was predominantly dependent on soil organic carbon content. The presence of DOC and oxalate resulted in higher desorption of phenanthrene compared to water alone, and the effects were positively related to soil organic carbon content and DOC/oxalate concentration. The facilitating effects of DOC were further increased during the second consecutive desorption, whereas oxalate had no such effect. Ultra-high-resolution Fourier transform-ion cyclotron resonance-mass spectrometry confirmed the molecular fractionation of DOC at the soil-water interface during DOC sorption. Specifically, the DOC molecules with O-rich moieties were preferentially adsorbed, whereas the molecules with phenolic and aromatic structures were selectively retained in the soil solutions through competitive displacement and co-sorption reactions during sorption. The enriched phenyl structures in the retained DOC facilitated its association with phenanthrene in the solutions and thus the release of phenanthrene from the soils. In contrast, oxalate replaced some organic carbon from the soils and thus released the associated phenanthrene into the solutions. Our findings highlight the importance of the molecular composition and structure of DOC for the desorption of phenanthrene in soil-water environments, which may help improve our understanding of the release and transport of organic compounds in the environments.

2.
J Chem Inf Model ; 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31430151

RESUMO

Aggregation has been posing a great challenge in drug discovery. Current computational approaches aiming to filter out aggregated molecules based on their similarity to known aggregators, such as Aggregator Advisor, have low prediction accuracy, and therefore development of reliable in silico models to detect aggregators is highly desirable. In this study, we built a data set consisting of 12 119 aggregators and 24 172 drugs or drug candidates and then developed a group of classification models based on the combination of two ensemble learning approaches and five types of molecular representations. The best model yielded an accuracy of 0.950 and an area under the curve (AUC) value of 0.987 for the training set, and an accuracy of 0.937 and an AUC of 0.976 for the test set. The best model also gave reliable predictions to the external validation set with 5681 aggregators since 80% of molecules were predicted to be aggregators with a prediction probability higher than 0.9. More importantly, we explored the relationship between colloidal aggregation and molecular features, and generalized a set of simple rules to detect aggregators. Molecular features, such as log D, the number of hydroxyl groups, the number of aromatic carbons attached to a hydrogen atom, and the number of sulfur atoms in aromatic heterocycles, would be helpful to distinguish aggregators from nonaggregators. A comparison with numerous existing druglikeness and aggregation filtering rules and models used in virtual screening verified the high reliability of the model and rules proposed in this study. We also used the model to screen several curated chemical databases, and almost 20% of molecules in the evaluated databases were predicted as aggregators, highlighting the potential high risk of aggregation in screening. Finally, we developed an online Web server of ChemAGG ( http://admet.scbdd.com/ChemAGG/index ), which offers a freely available tool to detect aggregators.

3.
Talanta ; 205: 120093, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450431

RESUMO

To extend the ion structure analysis capability of Fourier transform mass spectrometry (FT-MS), both time-domain and frequency-domain methods have been developed to extract ion collision cross sections (CCS) from high resolution mass spectra in Fourier transform ion cyclotron resonance (FT-ICR) cells. In this study, a new frequency-domain method, namely the line shape fitting method, was proposed to calculate ion CCSs from FT-ICR mass spectra line shape. Besides experimental data, simulated data with precisely controlled signal to noise levels and decay factors were also applied to characterize this method. Compared with the linewidth correction method previously proposed by our group, this line shape fitting method is more tolerant to noise, data length, and sampling rate, thus providing more consistent results. More importantly, CCS measurements of angiotensin I, bradykinin, ubiquitin and cytochrome c show that the resolving power is improved with the new method.

4.
Oral Oncol ; 95: 157-163, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31345384

RESUMO

OBJECTIVES: Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy worldwide, with a high mortality. The prognosis of OSCC remains unsatisfactory; the dysregulated immune system plays an important role in the pathogenesis of OSCC. Myeloid-derived suppressor cells (MDSCs) have been identified as immune-suppressive cells in multiple tumor types. The aim of this study was to clarify the underlying immunoregulatory mechanism of MDSC in patients with OSCC. MATERIALS AND METHODS: Flow cytometry was used to analyze the phenotype of MDSC among peripheral blood mononuclear cells (PBMCs) from patients with OSCC and healthy control subjects. The correlation between MDSC frequency and the disease index of patients with OSCC was evaluated. T cell proliferation experiment was used to evaluate the immunosuppressive function of MDSC. RESULTS: Patients with OSCC exhibited significantly higher levels of PMN-MDSCs than did healthy controls. In the co-culture assay, T cell proliferation and IFN-γ production were abrogated by the addition of PMN-MDSCs in a dose-dependent manner. The levels of reactive oxygen species were higher for PMN-MDSCs derived from patients with OSCC than for those from normal individuals. p-STAT3 levels, a key activator of MDSCs, was higher in OSCC-related PMN-MDSCs than in those from healthy controls. Both of these effects were reversed by NAC (an ROS inhibitor) and JSI-124 (a p-STAT3 inhibitor). Finally, PMN-MDSC levels were positively related to histological differentiation, nodal metastasis, and recurrence. CONCLUSION: PMN-MDSCs were elevated in OSCC patients, with strong immune-suppressive effects via p-STAT3/reactive oxygen species, providing a new direction for therapeutic strategies.

5.
J Environ Manage ; 247: 561-569, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31260922

RESUMO

An emission permit system (EPS) is a fixed-source environmental management system that is widely practiced worldwide. Since 2016, China has been building a fixed-source environmental management system with the EPS as its core. This paper summarizes the evolutionary process of China's EPS over the past 40 years considering four main stages: embryonic stage, local pilot stage, total emission control-based exploration stage, and reform stage of the core management system. This paper notes that China initially established a system of laws and technical specifications for emission permits, and emission permits are clearly becoming a mainstream trend in fixed-source management. The paper argues that there are still four problems in the current EPS reform (i.e., insufficient support of laws and regulations, poor integration of the EPS with other systems, unscientific design of the EPS, and insufficient implementation capacity after permit allocation). This paper puts forward 7 suggestions for further EPS reform, e.g., accelerating the formulation of the regulations on the EPS, strengthening the coordination with other fixed-source systems, improving the technical support system for the EPS, establishing a database system for emission permits, building a scientific and reasonable allocation method, improving the autonomy of pollutant monitoring in enterprises, and increasing information disclosure and public participation. The results may more accurately evaluate China's EPS in China's environmental protection system, provide scientific support for the promotion and development of the ongoing EPS reform and environmental management systems. The results may promote the development of pollution prevention, and an improvement in the environmental quality in China, and offer scientific guidance and reference for other countries to implement their own EPS.

6.
Plant Cell Rep ; 2019 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-31352584

RESUMO

KEY MESSAGE: RNA-Seq was employed to compare the transcriptome differences between the triticale lines and to identify the key gene responsible for the blue aleurone trait. The accumulation of anthocyanins in the aleurone of triticale results in the formation of the blue-grained trait, but the identity of the genes associated with anthocyanin biosynthesis in the aleurone has not yet been reported. In this manuscript, RNA-Seq was employed to compare the transcriptome differences between the triticale lines HM13 (blue aleurone) and HM5 (white aleurone), and to identify the key genes responsible for the blue aleurone trait. There were 32,406 differentially expressed genes between HM13 and HM5. Seventy-three unigenes were homologous to the structural genes related to anthocyanin biosynthesis, and the average transcript level of the structural genes was higher in HM13 than in HM5, so that quantitative differences between the two lines in transcription rates could be the cause of the blue aleurone. The MYB and bHLH transcription factors had two homologous unigenes, but contained only one differentially expressed unigene each. The relative transcript level of bHLH Unigene5672_All (TsMYC2) in HM13 was 42.71 times that in HM5, while the relative transcript level of the MYB transcription factor Unigene12228_All in HM13 was 2.20 times that in HM5. qPCR experiments determined the relative transcript level of TsMYC2 in developing grain, with the expression of TsMYC2 in grain being the highest compared with that in root, stem or leaf tissue. TsMYC2 was homologous to the bHLH transcription factor regulating anthocyanin biosynthesis and contained three entire functional domains: bHLH-MYC_N, HLH and ACT-like, which were important for exercising regulation of anthocyanin biosynthesis as a bHLH transcription factor. Transient expression of ZmC1 and TsMYC2 could induce anthocyanin biosynthesis in white wheat coleoptile cells, demonstrating that TsMYC2 was a functional bHLH transcription factor. These results indicated that TsMYC2 was associated with the blue aleurone trait and could prove to be a valuable gene with which to breed new triticale cultivars with the blue aleurone trait.

7.
Neurol Res ; 41(9): 857-866, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31266412

RESUMO

Objective: We aimed to evaluate the influence of a novel designed intensive patient care program (IPCP) on cognitive impairment, anxiety, depression and relapse-free survival (RFS) in acute ischemic stroke (AIS) patients. Methods: Two hundred forty-two AIS patients were consecutively recruited in this randomized controlled study and randomly allocated to IPCP group or control group as 1:1 ratio. Patients received IPCP and conventional treatment in IPCP group, while received usual education, cognitive rehabilitation training and conventional treatment in control group for 12-month intervention. Cognitive impairment, anxiety and depression were assessed by Mini-Mental State Examination (MMSE), Hospital Anxiety and Depression Scale (HADS) anxiety (HADS-A), and HADS depression (HADS-D) at baseline (M0), month (M)3, M6 and M12. After intervention, patients were followed up until 2018/7/30 and RFS was calculated. Results: IPCP increased MMSE score at M12 and change of MMSE score (M12-M0), while decreased cognitive impairment rate at M12. For anxiety, decreased change of HADS-A score (M12-M0) and lower anxiety rate at M12 were observed in IPCP group compared to control group. For depression, decreased HADS-D score at M6 and M12, reduced change of HADS-D score (M12-M0) and lower depression rate at M12 were shown in IPCP group compared to control group. Besides, RFS was numerically longer in IPCP group compared to control group, but without statistical significance. Conclusions: IPCP presents with a positive influence on improving cognitive impairment and decreasing anxiety as well as depression, while a less effect on improving RFS in AIS patients. Abbreviation: IPCP: intensive patient care program; RFS: relapse free survival; AIS: acute ischemic stroke; MRA: magnetic resonance angiography; ITT: intention-to-treat; LOCF: last observation carried forward.

8.
Artif Cells Nanomed Biotechnol ; 47(1): 2545-2552, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31213095

RESUMO

Tetramethylpyrazine (TMP) is a traditional Chinese medicine with anti-inflammation and immunomodulatory effects. In this context, our purpose was to investigate the associated regulatory mechanisms of TMP against lipopolysaccharide (LPS)-caused pancreatic ß cell Min6 injury. The injury of Min6 cells was induced by 10 µg/mL of LPS. Viability of Min6 cells was detected through CCK-8 assay, apoptosis process through flow cytometry, and the proteins involved in apoptosis through western blot. Insulin secretion was valued through the glucose-stimulated insulin secretion (GSIS) assay. microRNA-101 (miR-101) was measured through qRT-PCR. Mitogen-activated protein kinase phosphatase 1 (MKP-1) and signaling regulators was measured through western blot. We found that, TMP treatment effectively attenuated LPS-induced injury in Min6 cells by suppressing cell apoptosis and promoting insulin secretion. Further investigation revealed that TMP exerted protective effect through down-regulating miR-101, and MKP-1 was demonstrated as a target of miR-101. Moreover, TMP attenuated LPS-triggered inflammation by inactivating the JNK1/2 and NF-κB through the down-regulation of miR-101. In conclusion, our present study revealed that TMP alleviated LPS-induced injury in pancreatic ß-cell Min6 injury via regulation of miR-101/MKP-1 with the bluntness of JNK1/2 and NF-κB pathways.

10.
Infect Genet Evol ; 73: 384-389, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31173934

RESUMO

Toll-like receptors (TLRs) mediate the recognition of Helicobacter pylori (H. pylori) and initiate the innate immune response to infection. Genetic polymorphisms of TLRs play important roles in gastric carcinogenesis. The aim of this study was to determine the association between single nucleotide polymorphisms (SNPs) in TLR genes and H. pylori infection in the prognosis of gastric cancer (GC). A total of 756 GC patients were included in this study. Nine SNPs (TLR2: rs3804100, rs7696323, and rs10116253; TLR4: rs10983755, rs11536878, rs1927914, and rs7873784; TLR5: rs5744174; and TLR9: rs187084) in TLR genes were genotyped by MassARRAY assay. Kaplan-Meier survival curves and Cox regression were employed to conduct the associations between SNPs in TLRs and the survival of GC. Multivariate Cox regression indicated that patients with the TLR2 rs3804100 TT genotype exhibited worse survival than those with the CC + CT genotype (HR = 1.262, 95% CI: 1.006-1.582). No significant interaction between rs3804100 and H. pylori infection was observed for the prognosis of GC. Our results suggested that the TLR2 rs3804100 polymorphism may be a potential prognostic biomarker for GC independent of the H. pylori infection-related pathway.

11.
Chem Commun (Camb) ; 55(56): 8154-8157, 2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31241073

RESUMO

Herein, one dimensional copper-nickel sulfide nanowires (NWs) were, for the first time, synthesized by using an accurate one-pot multi-step wet chemistry strategy. The obtained copper-nickel sulfide NW electrocatalysts exhibit superb performance for both the hydrogen evolution reaction and oxygen evolution reaction, which is mainly due to the active centers Cu2S, NiS and Ni3S2.

12.
J Chem Theory Comput ; 15(6): 3654-3665, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31117479

RESUMO

With the development of theoretical and computational chemistry, as well as high-performance computing, molecular simulation can now be used not only as a tool to explain the experimental results but also as a means for discovery or prediction. Quantum chemical nanoreactor is such a method which can automatically explore the chemical process based only on the basic mechanics without prior knowledge of the reactions. Here, we present a new method which combines the semiempirical quantum mechanical density functional tight-binding (DFTB) method with the nanoreactor molecular dynamic (NMD) method, and we simulated the reaction process of graphene synthesis via detonation at different oxygen/acetylene mole ratios. The formation of graphene is initiated by the breaking of acetylene (C2H2) molecules by collision into pieces such as H atoms, ethynyl (HC≡C•), and vinylidene (H2C═C:) radicals. It is followed by the formation of long straight carbon chains coupled with a few branched carbon chains, which then turned into  a 2-D framework made of carbon rings. Trace oxygen could modulate the size of the rings during graphene formation and promote the formation of regular graphene with fused six-membered rings as we see, but the addition of high oxygen content makes more C-containing species oxidized to small oxide molecules instead of polymerization. The calculation speed of the DFTB nanoreactor is greatly improved compared to the ab initio nanoreactor, which makes it a valuable option to simulate chemical processes of large sizes and long time scales and to help us uncover the "unknown unknowns".

13.
BMC Plant Biol ; 19(1): 169, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31035916

RESUMO

BACKGROUND: Lycium ruthenicum Murray is an important economic plant in China and contains higher levels of anthocyanins in its fruits than other Lyciums. However, the genetic mechanism of anthocyanin production in this plant is unknown. RESULTS: Based on previous transcriptome analysis, LrAN2 and LbAN2, encoding MYB transcription factors, were isolated from L. ruthenicum and L. barbarum, respectively. Both genes contained two introns, encoded 257 amino acids with two-Aa difference, and carried the unabridged HTH-MYB, MYB-like DNA-binding, and SANT domains. In the phylogenetic trees, LrAN2 and LbAN2 were found to be closely related to NtAN2, which regulates anthocyanin biosynthesis in tobacco. Overexpression of LrAN2 and LbAN2 induced anthocyanin biosynthesis in all tissues of tobacco. The anthocyanin content in the leaves of transgenic lines with LbAN2 was lower than LrAN2. It indicated that the function of LbAN2 was weaker than LrAN2. The AN2 transcript could be detected only in the fruits of L. ruthenicum and increased during fruit development, accompanied by anthocyanin accumulation. In natural population, the alleles LrAN2 and LrAN2 were associated strictly with L. ruthenicum and L. barbarum, respectively. Moreover, an AN2 genetic diversity study suggested that Lyciums with yellow, white, purple, and jujube red fruits were derived from L. ruthenicum. CONCLUSIONS: Two AN2 alleles, from L. ruthenicum and L. barbarum, were functional MYB transcriptor regulating anthocyanin biosynthesis. The functional diversity and high expression level of LrAN2 could be the reason for high anthocyanin content in the fruit of L. ruthenicum. Lyciums with yellow, white, purple, and jujube red fruits were derived from L. ruthenicum based on AN2 sequence diversity. The results may be advantageous in identifying new varieties and breeding new cultivars.


Assuntos
Antocianinas/biossíntese , Genes de Plantas , Lycium/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Alelos , China , Frutas/genética , Frutas/crescimento & desenvolvimento , Genes myb , Variação Genética , Lycium/crescimento & desenvolvimento , Lycium/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo
14.
Biochem Biophys Res Commun ; 514(4): 1108-1114, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31101340

RESUMO

L-amino acids represent the most common amino acid form, most notably as protein residues, whereas D-amino acids, despite their rare occurrence, play significant roles in many biological processes. Amino acid racemases are enzymes that catalyze the interconversion of L- and/or D-amino acids. McyF is a pyridoxal 5'-phosphate (PLP) independent amino acid racemase that produces the substrate D-aspartate for the biosynthesis of microcystin in the cyanobacterium Microcystis aeruginosa PCC7806. Here we report the crystal structures of McyF in complex with citrate, L-Asp and D-Asp at 2.35, 2.63 and 2.80 Å, respectively. Structural analyses indicate that McyF and homologs possess highly conserved residues involved in substrate binding and catalysis. In addition, residues Cys87 and Cys195 were clearly assigned to the key catalytic residues of "two bases" that deprotonate D-Asp and L-Asp in a reaction independent of PLP. Further site-directed mutagenesis combined with enzymatic assays revealed that Glu197 also participates in the catalytic reaction. In addition, activity assays proved that McyF could also catalyze the interconversion of L-MeAsp between D-MeAsp, the precursor of another microcystin isoform. These findings provide structural insights into the catalytic mechanism of aspartate racemase and microcystin biosynthesis.

15.
Zhongguo Zhong Yao Za Zhi ; 44(7): 1410-1415, 2019 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-31090299

RESUMO

This research aims to develop an UHPLC method, based on core-shell column(i.e. superficially porous particles), for simultaneous determination of eight isoflavonoids including formononetin,(6αR,11αR)-3-hydroxy-9,10-dimethoxypterocarpan, calycosin-7-O-ß-D-glucopyranoside,(3R)-7,2-dihydroxy-3,4-dimethoxyisoflavone, calycosin, ononin,(6αR,11αR)-9,10-dimethoxypterocarpan-3-O-ß-D-glucopyranoside, and(3R)-7,2-dihydroxy-3,4-dimethoxyisoflavan-7-O-ß-D-glucopyranoside in Astragali Radix. The analysis was performed on an Agilent Poroshell EC-C_(18 )column(2.1 mm×100 mm, 2.7 µm) with 0.2% formic acid solution(A)-acetonitrile(B) as mobile phase for gradient elution. The flow rate was 0.5 mL·min~(-1), with column temperature of 40 ℃ and the wavelengths were set at 260 and 280 nm. According to the results, all calibration curves showed good linearity(R~2>0.999 8) within the tested concentration ranges. Both the intra-and inter-day precisions for 8 isoflavonoids were less than 0.80%, with the mean recovery at the range of 94.71%-104.6%. Thus, the newly developed UHPLC method using core-shell column owned the advantages in terms of rapid analysis, low column pressure and less solvent consumption, thus enabling the usage of conventional HPLC systems. Meanwhile, quantitative evaluation was carried out for 22 batches of commercial Astragali Radix. It has been found that great variations occurred for the content of the individual isoflavonoids among different batches; in contrast, the total content of total 8 isoflavonoids(>0.1%) was stable in most samples, indicating that it was reasonable to involve all isoflavonoids as the chemical markers for the quality control of Astragali Radix.


Assuntos
Astrágalo (Planta)/química , Medicamentos de Ervas Chinesas/normas , Flavonas/análise , Cromatografia Líquida de Alta Pressão , Compostos Fitoquímicos/análise , Raízes de Plantas/química , Controle de Qualidade
16.
BMC Plant Biol ; 19(1): 131, 2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30961525

RESUMO

BACKGROUND: The plant architecture has significant effects on grain yield of various crops, including soybean (Glycine max), but the knowledge on optimization of plant architecture in order to increase yield potential is still limited. Recently, CRISPR/Cas9 system has revolutionized genome editing, and has been widely utilized to edit the genomes of a diverse range of crop plants. RESULTS: In the present study, we employed the CRISPR/Cas9 system to mutate four genes encoding SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors of the SPL9 family in soybean. These four GmSPL9 genes are negatively regulated by GmmiR156b, a target for the improvement of soybean plant architecture and yields. The soybean Williams 82 was transformed with the binary CRISPR/Cas9 plasmid, assembled with four sgRNA expression cassettes driven by the Arabidopsis thaliana U3 or U6 promoter, targeting different sites of these four SPL9 genes via Agrobacterium tumefaciens-mediated transformation. A 1-bp deletion was detected in one target site of the GmSPL9a and one target site of the GmSPL9b, respectively, by DNA sequencing analysis of two T0-generation plants. T2-generation spl9a and spl9b homozygous single mutants exhibited no obvious phenotype changes; but the T2 double homozygous mutant spl9a/spl9b possessed shorter plastochron length. In T4 generation, higher-order mutant plants carrying various combinations of mutations showed increased node number on the main stem and branch number, consequently increased total node number per plants at different levels. In addition, the expression levels of the examined GmSPL9 genes were higher in the spl9b-1 single mutant than wild-type plants, which might suggest a feedback regulation on the expression of the investigated GmSPL9 genes in soybean. CONCLUSIONS: Our results showed that CRISPR/Cas9-mediated targeted mutagenesis of four GmSPL9 genes in different combinations altered plant architecture in soybean. The findings demonstrated that GmSPL9a, GmSPL9b, GmSPL9c and GmSPL9 function as redundant transcription factors in regulating plant architecture in soybean.


Assuntos
Sistemas CRISPR-Cas/genética , Edição de Genes , Soja/genética , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Homozigoto , Mutagênese Sítio-Dirigida , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Soja/anatomia & histologia , Fatores de Transcrição/genética
17.
Sci Rep ; 9(1): 5990, 2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-30979945

RESUMO

As major environment factors, drought or high salinity affect crop growth, development and yield. Transgenic approach is an effective way to improve abiotic stress tolerance of crops. In this study, we comparatively analyzed gene structures, genome location, and the evolution of syntaxin proteins containing late embryogenesis abundant (LEA2) domain. GmSYP24 was identified as a dehydration-responsive gene. Our study showed that the GmSYP24 protein was located on the cell membrane. The overexpression of GmSYP24 (GmSYP24ox) in soybean and heteroexpression of GmSYP24 (GmSYP24hx) in Arabidopsis exhibited insensitivity to osmotic/drought and high salinity. However, wild type soybean, Arabidopsis, and the mutant of GmSYP24 homologous gene of Arabidopsis were sensitive to the stresses. Under the abiotic stresses, transgenic soybean plants had greater water content and higher activities of POD, SOD compared with non-transgenic controls. And the leaf stomatal density and opening were reduced in transgenic Arabidopsis. The sensitivity to ABA was decreased during seed germination of GmSYP24ox and GmSYP24hx. GmSYP24hx induced up-regulation of ABA-responsive genes. GmSYP24ox alters the expression of some aquaporins under osmotic/drought, salt, or ABA treatment. These results demonstrated that GmSYP24 played an important role in osmotic/drought or salt tolerance in ABA signal pathway.

18.
World J Gastroenterol ; 25(8): 1012-1023, 2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30833806

RESUMO

BACKGROUND: The lethal-7 (let-7) family members and their targets are involved in the development and progression of tumors. Let-7-related polymorphisms have been reported to be associated with tumorigenesis and prognosis. In gastric cancer, however, the related studies are limited. AIM: To investigate the role of let-7-related microRNA polymorphisms in the tumorigenesis and prognosis of gastric cancer in a Chinese population. METHODS: A total of 898 gastric cancer patients and 992 tumor-free controls were recruited into this study from 2008 to 2013. Gastric cancer patients were followed periodically. Ten single nucleotide polymorphisms (SNPs) in the let-7 gene region or their target mRNAs were genotyped using the MassARRAY system and their associations with the risk for or overall survival of gastric cancer were analyzed. RESULTS: All the ten SNPs were in Hardy-Weinberg equilibrium. The C allele of the rs3811463 polymorphism in the 3'-untranslated region (UTR) of LIN28A was associated with a lower risk of gastric cancer [odds ratio (OR) = 0.74, 95% confidence interval (CI): 0.61-0.88, P = 0.001] after adjustment for age and Helicobacter pylori status. Seven hundred and thirty-five gastric cancer patients who had undergone radical tumorectomy were included in the survival analysis and their 5-year survival rate was 53.9% (95%CI: 50.1%-57.6%). The rs10889677 in the 3'-UTR of IL23R was corresponded to the prognosis of gastric cancer in a dose-response manner, in which the death risk increased by 25% [hazard ratio (HR) = 1.25, 95%CI: 1.04-1.45, P = 0.011] with each increase in the number of C alleles after controlling for other potential clinicopathological parameters. CONCLUSION: The let-7-related polymorphism rs3811463 in LIN28A is associated with the susceptibility to gastric cancer and the let-7-related polymorphism rs10889677 in IL23R is associated with the prognosis of gastric cancer.


Assuntos
Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/metabolismo , Proteínas de Ligação a RNA/genética , Receptores de Interleucina/genética , Neoplasias Gástricas/genética , Regiões 3' não Traduzidas/genética , Idoso , Grupo com Ancestrais do Continente Asiático/genética , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Prognóstico , Neoplasias Gástricas/mortalidade , Análise de Sobrevida
19.
Molecules ; 24(5)2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30866466

RESUMO

Red coleoptiles can help crops to cope with adversity and the key genes that are responsible for this trait have previously been isolated from Triticum aestivum, Triticum urartu, and Aegilops tauschii. This report describes the use of transcriptome analysis to determine the candidate gene that controls the trait for white coleoptiles in T. monococcum by screening three cultivars with white coleoptiles and two with red coleoptiles. Fifteen structural genes and two transcription factors that are involved in anthocyanin biosynthesis were identified from the assembled UniGene database through BLAST analysis and their transcript levels were then compared in white and red coleoptiles. The majority of the structural genes reflected lower transcript levels in the white than in the red coleoptiles, which implied that transcription factors related to anthocyanin biosynthesis could be candidate genes. The transcript levels of MYC transcription factor TmMYC-A1 were not significantly different between the white and red coleoptiles and all of the TmMYC-A1s contained complete functional domains. The deduced amino acid sequence of the MYB transcription factor TmMYB-A1 in red coleoptiles was homologous to TuMYB-A1, TaMYB-A1, TaMYB-B1, and TaMYB-D1, which control coleoptile color in corresponding species and contained the complete R2R3 MYB domain and the transactivation domain. TmMYB-a1 lost its two functional domains in white coleoptiles due to a single nucleotide deletion that caused premature termination at 13 bp after the initiation codon. Therefore, TmMYB-A1 is likely to be the candidate gene for the control of the red coleoptile trait, and its loss-of-function mutation leads to the white phenotype in T. monococcum.


Assuntos
Cotilédone/genética , Perfilação da Expressão Gênica/métodos , Fatores de Transcrição/genética , Triticum/anatomia & histologia , Antocianinas/biossíntese , Cotilédone/anatomia & histologia , Regulação da Expressão Gênica de Plantas , Sequenciamento de Nucleotídeos em Larga Escala , Mutação , Proteínas de Plantas/genética , Locos de Características Quantitativas , Análise de Sequência de RNA , Triticum/genética
20.
Sci Total Environ ; 670: 300-307, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-30904643

RESUMO

Adsorption of dissolved organic matter (DOM) onto soils plays an important role in the mobility and stabilization of organic carbon in soils; however, little attention has been paid to changes in the molecular components of soil DOM during adsorption on soils. In the present study, molecular fractionation of DOM induced by adsorption on a red soil was investigated using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The results indicated that compounds high in unsaturation or polarity or rich in oxygen had a high affinity to soil surfaces, while aliphatic compounds with few oxygenated groups and low polarity compounds were preferentially retained in solution. Among soil fractions with different particle sizes, the fine clay fraction with high iron content and surface area was the main contributor to the adsorptive fractionation of DOM. Comparison of the molecular fractionation of DOM derived from adsorption on soil with iron removed and on soil minerals with various iron contents and surface areas further indicated that iron containing minerals in the soil provided the major adsorptive sites and determined the molecular fractionation of DOM at the soil-water interface. The results provide molecular information for further understanding mechanisms underlying the persistence and mobility of organic carbon in soils.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA