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2.
Sci Total Environ ; 802: 149938, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525687

RESUMO

Deltamethrin (DM), a type II pyrethroid insecticide, is widely used to control agricultural pests. However, its excessive use exerts a detrimental effect on the ecological environment and human health, indicating the need to study its potential risks in detail. In the present study, zebrafish embryos were exposed to varying concentrations of DM (0.1, 1, 10, and 25 µg/L) for 96 h to assess the alterations in the transcript levels of proteins of the estrogenic and dopaminergic pathways. In addition, its effect on zebrafish locomotor activity was studied. The mRNA expression of cyp19a1b, erα, erß2, fshr, gnrh2, gnrhr3, vtg3, dat, and dr1 significantly changed after exposing the embryos to DM. Deltamethrin at 10 and 25 µg/L significantly reduced the average swimming speed of zebrafish larvae. In addition, embryos injected with zebrafish estrogen receptor α (erα) and ß (erß) morpholinos and co-exposed to 25 µg/L DM for 96 h showed reduced expression of vtg3 mRNA compared to embryos exposed to 25 µg/L DM only. The locomotor activity of erα and erß knockdown zebrafish following DM exposure was increased significantly when compared with that of larvae exposed to 25 µg/L DM only. Our results demonstrated that DM altered the locomotor activity of zebrafish larvae and the transcript levels of the components of estrogenic and dopaminergic pathways; erα and erß knockdown weakened these effects.


Assuntos
Piretrinas , Peixe-Zebra , Animais , Embrião não Mamífero , Humanos , Larva , Nitrilas , Piretrinas/toxicidade , Receptores de Estrogênio/genética
3.
J Mech Behav Biomed Mater ; 126: 105009, 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34861520

RESUMO

Polyvinyl alcohol hydrogel (PVA-H) has been widely used in clinical transplantation because of its high water content, good biocompatibility and mechanical properties. However, PVA-H have some problems, such as low elongation at break, low fatigue resistance and high friction coefficient, which hinders its application in clinic. In this paper, a novel high-performance PVA hydrogel enhanced by chemical double crosslinking (CDC) method had been synthesized. The influences of chemical crosslinking agent concentration on mechanical properties, friction properties and fatigue properties of materials were systematically investigated, in order to meet the clinical application of artificial meniscus, artificial cartilage, nucleus pulposus and so on. As a result, due to the introduction of chemical bonds, CDC hydrogels have over 600% elongation at break, modulus loss after fatigue test was reduced by 42%, average coefficient during friction was reduced to 0.048, and biocompatibility performance was excellent. The PVA hydrogel enhanced by CDC method provides a new concept for us to prepare high-performance PVA hydrogel and a promising material to replace cartilage, meniscus, nucleus pulposus and other tissues.

4.
Int J Mol Sci ; 22(24)2021 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-34948380

RESUMO

Heavy metals negatively affect soil quality and crop growth. In this study, we compared the tolerance of six ryegrass cultivars to cobalt (Co2+), lead (Pb2+), and nickel (Ni2+) stresses by analyzing their physiological indexes and transcript levels of genes encoding metal transporters. Compared with the other cultivars, the cultivar Lm1 showed higher germination rates and better growth under Co2+, Pb2+, or Ni2+ treatments. After 48 h of Co2+ treatment, the total antioxidant capacity of all six ryegrass cultivars was significantly increased, especially that of Lm1. In contrast, under Pb2+ stress, total antioxidant capacity of five cultivars was significantly decreased, but that of Lm1 was unaffected at 24 h. Staining with Evans blue dye showed that the roots of Lm1 were less injured than were roots of the other five ryegrass cultivars by Co2+, Pb2+, and Ni2+. Lm1 translocated and accumulated lesser Co2+, Pb2+, and Ni2+ than other cultivars. In Lm1, genes encoding heavy metal transporters were differentially expressed between the shoots and roots in response to Co2+, Pb2+, and Ni2+. The aim of these researches could help find potential resource for phytoremediation of heavy metal contamination soil. The identified genes related to resistance will be useful targets for molecular breeding.

5.
Mar Drugs ; 19(12)2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34940650

RESUMO

Alcalase, neutral protease, and pepsin were used to hydrolyze the skin of Takifugu flavidus. The T. flavidus hydrolysates (TFHs) with the maximum degree of hydrolysis (DH) and angiotensin-I-converting enzyme (ACE)-inhibitory activity were selected and then ultra-filtered to obtain fractions with components of different molecular weights (MWs) (<1, 1-3, 3-10, 10-50, and >50 kDa). The components with MWs < 1 kDa showed the strongest ACE-inhibitory activity with a half-maximal inhibitory concentration (IC50) of 0.58 mg/mL. Purification and identification using semi-preparative liquid chromatography, Sephadex G-15 gel chromatography, RP-HPLC, and LC-MS/MS yielded one new potential ACE-inhibitory peptide, PPLLFAAL (non-competitive suppression mode; IC50 of 28 µmmol·L-1). Molecular docking and molecular dynamics simulations indicated that the peptides should bind well to ACE and interact with amino acid residues and the zinc ion at the ACE active site. Furthermore, a short-term assay of antihypertensive activity in spontaneously hypertensive rats (SHRs) revealed that PPLLFAAL could significantly decrease the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of SHRs after intravenous administration. These results suggested that PPLLFAAL may have potential applications in functional foods or pharmaceuticals as an antihypertensive agent.

6.
Mar Drugs ; 19(12)2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34940654

RESUMO

Angiotensin-I-converting enzyme (ACE) is a crucial enzyme or receptor that catalyzes the generation of potent vasopressor angiotensin II (Ang II). ACE inhibitory peptides from fish showed effective ACE inhibitory activity. In this study, we reported an ACE inhibitory peptide from Takifugu bimaculatus (T. bimaculatus), which was obtained by molecular docking with acid-soluble collagen (ASC) hydrolysate of T. bimaculatus. The antihypertensive effects and potential mechanism were conducted using Ang-II-induced human umbilical vein endothelial cells (HUVECs) as a model. The results showed that FNLRMQ alleviated the viability and facilitated apoptosis of Ang-II-induced HUVECs. Further research suggested that FNLRMQ may protect Ang-II-induced endothelial injury by regulating Nrf2/HO-1 and PI3K/Akt/eNOS signaling pathways. This study, herein, reveals that collagen peptide FNLRMQ could be used as a potential candidate compound for antihypertensive treatment, and could provide scientific evidence for the high-value utilization of marine resources including T. bimaculatus.

7.
Artigo em Chinês | MEDLINE | ID: mdl-34743496

RESUMO

BACKGROUND: The curative potential of various bronchoscopic treatments such as electric snare, carbon dioxide freezing, argon plasma coagulation (APC), Neudymium-dopted Yttrium Aluminium Garnet (Nd:YAG) laser and photodynamic therapy (PDT) for the treatment of intraluminal tumor has been administered previously, but this regimen is not common in the treatment of typical carcinoid. The aim of this study is to investigate the curative effects both in short-term and long-term of interventional bronchoscopy in the treatment of typical carcinoid. METHODS: We retrospectively reviewed the clinical data of typical carcinoid patients who were treated with interventional bronchoscopy for tumor suppression and they were hospitalized in the Emergency General Hospital from December 2010 to December 2020, and Wilcoxon rank sum test and chi-square test were used for analysis. RESULTS: A total of 32 patients were included, including 18 cases of preoperative bronchial artery embolization (embolization rate 56%, 95%CI: 31%-79%). The grade score of dyspnea decreased from before treatment to after treatment, and the difference was statistically significant [(1.44±1.03) score vs (0.25±0.58) score, P=0.003]; The degree of bronchial stenosis decreased from pre-treatment to post-treatment, and the difference was statistically significant [(87.50%±13.90%) vs (17.50%±6.83%), P=0.000]; There was significant difference in bronchial diameter before and after treatment [(0.14±0.18) cm vs (0.84±0.29) cm, P=0.000]. CONCLUSIONS: Bronchoscopic interventional therapy has significant short-term and long-term effects in the treatment of typical carcinoid.

8.
Mar Drugs ; 19(11)2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34822510

RESUMO

Pufferfish is increasingly regarded by many as a delicacy. However, the tetrodotoxin (TTX) that accumulates in its body can be lethal upon consumption by humans. TTX is known to mainly accumulate in pufferfish skin, but the accumulation mechanisms are poorly understood. In this study, we aimed to explore the possible mechanism of TTX accumulation in the skin of the pufferfish Takifugu flavidus following treatment with TTX. Through liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, we detected 37.3% of toxin accumulated in the skin at the end of the rearing period (168 h). Transcriptome and proteome analyses revealed the mechanism and pathways of TTX accumulation in the skin of T. flavidus in detail. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes analyses strongly suggest that cardiac muscle contraction and adrenergic signaling in cardiomyocyte pathways play an important role in TTX accumulation. Moreover, some upregulated and downregulated genes, which were determined via RNA-Seq, were verified with qPCR analysis. This study is the first to use multi-omics profiling data to identify novel regulatory network mechanisms of TTX accumulation in the skin of pufferfish.

9.
Ecotoxicol Environ Saf ; 228: 113023, 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34839138

RESUMO

The extensively studied cAMP-dependent protein kinase A (PKA) is involved in the regulation of critical cell processes, including metabolism, gene expression, and cell proliferation. Therefore, PKA has been viewed increasingly as potential target for variety of drugs and environmental endocrine disruptors. Consequentially, the preparation of PKA protein became an important initial step for the subsequent exploration of PKA's character in endocrine disrupting effects of pesticides. To investigate PKA protein, which is potential to be the environmental endocrine toxicity target of triazole fungicides, a strategy to heterologously express protein kinase A catalytic alpha subunit of human (hPKAcα) and zebrafish (zPKAcα) in Escherichia coli (E. coli) BL21(DE3) host cells was demonstrated. After optimizing conditions and protein purification, we successfully obtained enzymatically active hPKAcα and zPKAcα. Western blot analysis indicated that the recombinant hPKAcα and zPKAcα still retained their characteristic antigenicity and binding activity, while in vitro kinase activity assays revealed that the recombinant hPKAcα and zPKAcα maintained enzyme activity. By in silico methods including homology modelling and molecular docking, the affinity of ligands and the models of hPKAcα and zPKAcα were further tested. The present study offered a valuable method to achieve the prokaryotic expression of a eukaryotic protein kinase and laid a foundation to facilitate further investigation of toxicological target of triazole pesticides.

10.
J Nanobiotechnology ; 19(1): 344, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34706736

RESUMO

BACKGROUND: The use of magnetic nanozymes (NZs) with the ability to synchronize gas therapy through photodynamic and chemotherapy in the treatment of breast cancer has received much attention. RESULTS: Hence, in this study, we designed a bovine lactoferrin-coated iron sulfide NZs containing doxorubicin (abbreviated as: FeS-Dox@bLf NZs) by wet-chemical synthesis method. Then, the physicochemical characteristics of synthesized NZs were explored by several methods. Also, the level of Fe2+, H2S and Dox releases from FeS-Dox@Lf NZs. Also, the cytotoxic effects of FeS-Dox@Lf NZs were investigated by cellular assays. After intravenous injections of NZs and laser irradiation, significant effects of FeS-Dox@Lf NZs on mice weight and tumor status were observed. Afterwards, not only the distribution of Dox in the body was examined by fluorescent, but also the time of Fe clearance and the amount of Dox and Fe retention in vital tissues were determined. The findings confirm that FeS-Dox@Lf NZs, in addition to targeted drug distribution in tumor tissue, resulted in superior therapeutic performance compared to free Dox due to reduced Dox side effects in vital tissues, and increased level of free radicals in 4T1 cells. CONCLUSION: Overall, FeS-Dox@Lf NZs with the ability to synchronize chemotherapy and gas therapy raised hopes for more effective treatment of breast cancer.

11.
Front Cell Dev Biol ; 9: 666303, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34631693

RESUMO

The WNT signaling pathway plays a crucial role in oviduct/fallopian development. However, the specific physiological processes regulated by the WNT pathway in the fallopian/oviduct function remain obscure. Benefiting from the Lgr4 knockout mouse model, we report the regulation of oviduct epithelial secretion by LGR4. Specifically, the loss of Lgr4 altered the mouse oviduct size and weight, severely reduced the number of oviductal epithelial cells, and ultimately impaired the epithelial secretion. These alterations were mediated by a failure of CTNNB1 protein accumulation in the oviductal epithelial cytoplasm, by the modulation of WNT pathways, and subsequently by a profound change of the gene expression profile of epithelial cells. In addition, selective activation of the WNT pathway triggered the expression of steroidogenic genes, like Cyp11a1 and 3ß-Hsd1, through the activation of the transcriptional factor NR5A2 in an oviduct primary cell culture system. As demonstrated, the LGR4 protein modulates a WNT-NR5A2 signaling cascade facilitating epithelial secretory cell maturation and steroidogenesis to safeguard oviduct development and function in mice.

12.
Front Microbiol ; 12: 738282, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34650539

RESUMO

The gene encoding a putative phosphatidate phosphatase (PAP) from tolerant saline-alkali (TSA) Chlorella, ChPAP, was identified from a yeast cDNA library constructed from TSA Chlorella after a NaCl treatment. ChPAP expressed in yeast enhanced its tolerance to NaCl and sorbitol. The ChPAP protein from a GFP-tagged construct localized to the plasma membrane and the lumen of vacuoles. The relative transcript levels of ChPAP in Chlorella cells were strongly induced by NaCl and sorbitol as assessed by northern blot analyses. Thus, ChPAP may play important roles in promoting Na-ion movement into the cell and maintaining the cytoplasmic ion balance. In addition, ChPAP may catalyze diacylglycerol pyrophosphate to phosphatidate in vacuoles.

13.
Int J Mol Sci ; 22(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34502271

RESUMO

Adonis amurensis is a perennial herbaceous flower that blooms in early spring in northeast China, where the night temperature can drop to -15 °C. To understand flowering time regulation and floral organogenesis of A. amurensis, the MIKCc-type MADS (Mcm1/Agamous/ Deficiens/Srf)-box genes were identified and characterized from the transcriptomes of the flower organs. In this study, 43 non-redundant MADS-box genes (38 MIKCc, 3 MIKC*, and 2 Mα) were identified. Phylogenetic and conserved motif analysis divided the 38 MIKCc-type genes into three major classes: ABCDE model (including AP1/FUL, AP3/PI, AG, STK, and SEPs/AGL6), suppressor of overexpression of constans1 (SOC1), and short vegetative phase (SVP). qPCR analysis showed that the ABCDE model genes were highly expressed mainly in flowers and differentially expressed in the different tissues of flower organs, suggesting that they may be involved in the flower organ identity of A. amurensis. Subcellular localization revealed that 17 full-length MADSs were mainly localized in the nucleus: in Arabidopsis, the heterologous expression of three full-length SOC1-type genes caused early flowering and altered the expression of endogenous flowering time genes. Our analyses provide an overall insight into MIKCc genes in A. amurensis and their potential roles in floral organogenesis and flowering time regulation.


Assuntos
Adonis/genética , Flores/genética , Flores/metabolismo , Proteínas de Domínio MADS/classificação , Proteínas de Domínio MADS/genética , Proteínas de Plantas/genética , Arabidopsis/genética , Flores/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Genes de Plantas/fisiologia , Proteínas de Domínio MADS/química , Proteínas de Domínio MADS/metabolismo , Modelos Genéticos , Componentes Aéreos da Planta/genética , Componentes Aéreos da Planta/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Transcriptoma
14.
Metallomics ; 13(7)2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34160615

RESUMO

Homeostasis of microelements in organisms is vital for normal metabolism. In plants, the cation diffusion facilitator (CDF) protein family, also known as metal tolerance proteins (MTPs), play critical roles in maintaining trace metal homeostasis. However, little is known about these proteins in wheat. In this study, we characterized the MTP family of Triticum urartu, the donor of 'A' genome of Triticum aestivum, and analysed their phylogenetic relationships, sequence signatures, spatial expression patterns in the diploid wheat, and their transport activity when heterologously expressed. Nine MTPs were identified in the T. urartu genome database, and were classified and designated based on their sequence similarity to Arabidopsis thaliana (Arabidopsis) and Oryza sativa MTPs. Phylogenetic and sequence analyses indicated that the triticum urartu metal tolerance protein (TuMTP)s comprise three Zn-CDFs, two Fe/Zn-CDFs, and four Mn-CDFs; and can be further classified into six subgroups. Among the TuMTPs, there are no MTP2-5 and MTP9-10 counterparts but two MTP1/8/11 orthologs in relation to AtMTPs. It was also shown that members of the same cluster share similar sequence characteristic, i.e. number of introns, predicted transmembrane domains, and motifs. When expressed in yeast, TuMTP1 and TuMTP1.1 conferred tolerance to Zn and Co but not to other metal ions; while TuMTP8, TuMTP8.1, TuMTP11, and TuMTP11.1 conferred tolerance to Mn. When expressed in Arabidopsis, TuMTP1 localized to the tonoplast and significantly enhanced Zn and Co tolerance. TuMTPs showed diverse tissue-specific expression patterns. Taken together, the closely clustered TuMTPs share structural features and metal specificity but play diverse roles in the homeostasis of microelements in plant cells.

15.
Biochem Biophys Res Commun ; 561: 88-92, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-34020143

RESUMO

Cold-regulated (COR) genes are considered downstream functional genes in the cold-response pathway. However, we identified a plasma membrane-type, AtCor413pm1, as a regulatory gene for the abscisic acid (ABA) response, and found that ABA induced it predominantly in Arabidopsis roots, vasculature, stipules, and guard cells. Differentially expressed genes combined with qPCR analysis revealed the expressions of three ABA-responsive genes (AtDTX50, AtABR1, and AtCIPK20) were significantly altered in the ABA-treated atcor413pm1 mutant, compared to the wild-type. Furthermore, the ABA-induced transient Ca2+ oscillation in the plasma membrane of atcor413pm1 roots was different from that observed in the wild-type. Our results revealed that AtCor413pm1 might play a role in the cross-talk between the ABA and stress response pathways.


Assuntos
Ácido Abscísico/farmacologia , Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Mutação , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Membrana Celular/metabolismo , Temperatura Baixa , Reguladores de Crescimento de Plantas/farmacologia , Transdução de Sinais
16.
Chemosphere ; 281: 130868, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34010720

RESUMO

In this paper, a simple and efficient regeneration technology of low-temperature pickling regeneration process is proposed for Cu(II)-adsorbed activated carbon fiber felts (ACFFs). The regeneration process mainly uses the strong oxidation of acidic regenerant above boiling point to regenerate ACFFs in a confined space. With no demand for high temperature and high pressure, the regeneration process achieves a high efficiency regeneration and a remarkable enhancement of Cu(II) adsorptivity simultaneously for Cu(II)-adsorbed ACFFs. After parameter optimization, the pickling temperature of 383 K, pickling time of 3 h and HNO3 concentration of 150 g/L are adopted as optimum process parameters for the reutilization of ACFFs. The regeneration rates of ACFFs in five cycles are maintained at 424.08%-829.59%. Analytical results show that the enhancement of Cu(II) adsorptivity is mainly caused by the remarkable enhancement of specific surface area (increased by 106.08%), micropore volume (increased by 102.17%) and more abundant surface chemical structure (particularly carboxyl and nitro group) after treated by the regeneration process.


Assuntos
Carvão Vegetal , Adsorção , Fibra de Carbono , Oxirredução , Temperatura
17.
Mar Drugs ; 19(4)2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33806251

RESUMO

The von Willebrand factor type D (VWD) domain in vitellogenin has recently been found to bind tetrodotoxin. The way in which this protein domain associates with tetrodotoxin and participates in transporting tetrodotoxin in vivo remains unclear. A cDNA fragment of the vitellogenin gene containing the VWD domain from pufferfish (Takifugu flavidus) (TfVWD) was cloned. Using in silico structural and docking analyses of the predicted protein, we determined that key amino acids (namely, Val115, ASP116, Val117, and Lys122) in TfVWD mediate its binding to tetrodotoxin, which was supported by in vitro surface plasmon resonance analysis. Moreover, incubating recombinant rTfVWD together with tetrodotoxin attenuated its toxicity in vivo, further supporting protein-toxin binding and indicating associated toxicity-neutralizing effects. Finally, the expression profiling of TfVWD across different tissues and developmental stages indicated that its distribution patterns mirrored those of tetrodotoxin, suggesting that TfVWD may be involved in tetrodotoxin transport in pufferfish. For the first time, this study reveals the amino acids that mediate the binding of TfVWD to tetrodotoxin and provides a basis for further exploration of the molecular mechanisms underlying the enrichment and transfer of tetrodotoxin in pufferfish.


Assuntos
Proteínas de Peixes/metabolismo , Takifugu/metabolismo , Tetrodotoxina/metabolismo , Vitelogeninas/metabolismo , Fator de von Willebrand/metabolismo , Animais , Proteínas de Peixes/genética , Simulação de Acoplamento Molecular , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Vitelogeninas/genética , Fator de von Willebrand/genética
18.
ACS Appl Mater Interfaces ; 13(14): 16846-16858, 2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33784813

RESUMO

Graphene oxide (GO) has been widely used as an additive of polyacrylonitrile (PAN)-based carbon nanofibers (CNFs) to optimize its crystal structure and improve the mechanical performances of nanofibers. However, the homogeneous dispersion of GO nanosheets among entangled PAN molecular chains is always challenging, and the poor dispersion of GO severely limits its positive effects on both the structure and performances of CNFs. Considering this issue, this paper provides for the first time an effective solution to achieve rapid and uniform introduction of GO in PAN-based nanofibers via in situ polymerization, and the optimization of the nanofiber structure by GO is systematically studied in three consecutive stages (polymerization, electrospinning, and carbonization) of the production process. During in situ polymerization, PAN is tightly attached on GO nanosheets to form PAN/GO nanocomposites, and this interaction is maintained throughout the spinning process. Not only the arrangement of PAN molecular chains but also the crystal size of the final turbostratic structure of CNFs is considerably improved by the interaction between PAN and GO. Besides, the direct proof that GO nanosheets promote the crystallization and orientation of the nanofiber matrix is presented. As a result, the tensile strength of CNFs is remarkably increased by 2.45 times with 0.5 wt % addition of GO. In summary, this paper provides a method for efficiently introducing nanoscale additives into PAN-based nanofibers and gives insights into the production of high-performance CNFs with the addition of GO.

19.
iScience ; 24(1): 101952, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33458611

RESUMO

As a promising target for alternative antimicrobials, bacterial recombinase A (RecA) protein has attracted much attention for its roles in antibiotic-driven SOS response and mutagenesis. Naphthalene polysulfonated compounds (NPS) such as suramin have previously been explored as antibiotic adjuvants targeting RecA, although the underlying structural bases for RecA-ligand interactions remain obscure. Based on our in silico predictions and documented activity of NPS in vitro, we conclude that the analyzed NPS likely interact with Tyr103 (Y103) and other key residues in the ATPase activity center (pocket A). For validation, we generated recombinant RecA proteins (wild-type versus Y103 mutant) to determine the binding affinities for RecA protein interactions with suramin and underexamined NPS in isothermal titration calorimetry. The corresponding dissociation constants (K d) ranged from 11.5 to 18.8 µM, and Y103 was experimentally shown to be critical to RecA-NPS interactions.

20.
Nat Plants ; 7(1): 60-72, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33398157

RESUMO

Cereal crop production is severely affected by seed-borne bacterial diseases across the world. Locally occurring disease resistance in various crops remains elusive. Here, we have observed that rice plants of the same cultivar can be differentiated into disease-resistant and susceptible phenotypes under the same pathogen pressure. Following the identification of a seed-endophytic bacterium as the resistance-conferring agent, integration of high-throughput data, gene mutagenesis and molecular interaction assays facilitated the discovery of the underlying mode of action. Sphingomonas melonis that is accumulated and transmitted across generations in disease-resistant rice seeds confers resistance to disease-susceptible phenotypes by producing anthranilic acid. Without affecting cell growth, anthranilic acid interferes with the sigma factor RpoS of the seed-borne pathogen Burkholderia plantarii, probably leading to impairment of upstream cascades that are required for virulence factor biosynthesis. The overall findings highlight the hidden role of seed endophytes in the phytopathology paradigm of 'disease triangles', which encompass the plant, pathogens and environmental conditions. These insights are potentially exploitable for modern crop cultivation threatened by globally widespread bacterial diseases.


Assuntos
Resistência à Doença , Endófitos , Oryza/imunologia , Doenças das Plantas/imunologia , Sementes/imunologia , Burkholderia/metabolismo , Resistência à Doença/fisiologia , Endófitos/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Sementes/microbiologia , Sphingomonas/fisiologia
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