Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
1.
Gastrointest Endosc ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38734256

RESUMO

BACKGROUND AND AIMS: After endoscopic full-thickness resection (EFTR), defects require a reliable and sustained closure. We present a novel, through-the-scope "bow-tie" (TTS-BT) closing device enabling direct defect closure without scope withdrawal. This preclinical study aimed to evaluate the feasibility and safety of this device for large defect closure after EFTR in a porcine model. METHODS: Exposed EFTR was performed for virtual lesions >2 cm in the stomach of 12 pigs. Subsequently, TTS-BT closing devices were used for defect closure. Conventional metal clips were used to close any remaining defects. Gastroscopy was performed for 8 weeks to examine the wound sites, and the pigs were subsequently killed. After killing the pigs, the wound healing was histologically verified by hematoxylin and eosin staining. The primary outcome was a successful closure rate; secondary outcomes were complete healing rate, closure time, and incidence of adverse events. RESULTS: The median long and short diameters of perforations were 4.0 cm (range, 3.0-6.0 cm) and 3.0 cm (range, 2.0-4.0 cm), respectively. Defect closure using novel TTS-BT closure devices and conventional metal clips was successfully performed in all pigs. Complete healing was achieved in the defects of 12 pigs. The median closure time was 13 minutes (range, 9-38 minutes). No serious adverse events occurred during the 8-week follow-up. CONCLUSIONS: The novel TTS-BT closure device is feasible and safe for closing large gastric perforations and could be a promising tool for clinical practice.

2.
Dis Colon Rectum ; 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39254197

RESUMO

BACKGROUND: Continuous advancements and breakthroughs in flexible gastrointestinal endoscopy have led to alternatives to colonic anastomosis. OBJECTIVE: This study aimed to evaluate the feasibility and safety of end-to-end colonic anastomosis using a single flexible endoscope with the novel through-the-scope "bow-tie" (TTS-BT) device and conventional metal clips in a porcine model. DESIGN: Animal study. SETTINGS: Animal laboratory at China Medical University. PATIENTS: Eight healthy pigs were included. INTERVENTIONS: Eight animals underwent total colonic severance and anastomoses with through-the-scope "bow-tie" devices and metal clips. MAIN OUTCOME MEASURES: The primary outcomes were the success rate of the anastomosis and survival rate during 3-month follow-up. Furthermore, the secondary outcomes were anastomotic site healing, reintervention rate, and rate of anastomotic complications such as bleeding, leakage, stenosis, and obstruction. Six pigs were euthanized, and necropsies were performed 3 months postoperatively, while two pigs were fed for long-term observation. The anastomotic stoma was histologically analyzed using Hematoxylin-eosin and Masson's trichrome staining. RESULTS: End-to-end colonic anastomoses were successfully performed using through-the-scope "bow-tie" devices, and satisfactory healing was achieved in all pigs. The success rate of anastomosis was 100% (8/8). All animals survived postoperatively without anastomotic complications, including bleeding, leakage, or obstruction; however, two cases of stenosis occurred (25%), and one case (12.5%) required reintervention. LIMITATIONS: Large-scale studies should be conducted to verify the feasibility and safety of the through-the-scope "bow-tie" device in other parts of the intestine. CONCLUSIONS: Flexible endoscopy with the through-the-scope "bow-tie" device is feasible and safe for intraluminal colonic anastomosis. This study may expand the indications for full-thickness endoscopic resection in the future. See Video abstract.

3.
Inorg Chem ; 63(17): 7631-7639, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38625102

RESUMO

Two novel MoO42--templated luminescent silver alkynyl nanoclusters with 20-nuclearity ([(MoO42-)@Ag20(C≡CtBu)8(Ph2PO2)7(tfa)2]·(tfa-) (1)) and 18-nuclearity ([(MoO42-)@Ag18(C≡CtBu)8(Ph2PO2)7]·(OH) (2)) (tfa = trifluoroacetate) were synthesized with the green light maximum emissions at 507 and 516 nm, respectively. The nanoclusters were investigated and characterized by single-crystal X-ray crystallography, electrospray ionization mass spectrum (ESI-MS), X-ray photoelectron spectroscopy, thermogravimetry (TG), photoluminescence (PL), ultraviolet-visible (UV-vis) spectroscopy, and density functional theory calculations (DFT). The two nanoclusters differ in their structure by a supplementary [Ag2(tfa)2] organometallic surface motif, which significantly participates in the frontier molecular orbitals of 1, resulting in similar bonding patterns but different optical properties between the two clusters. Indeed, both nanoclusters show strong temperature-dependent photoluminescence properties, which make them potential candidates in the fields of optical devices for further applications.

4.
Gastrointest Endosc ; 97(5): 859-870.e5, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36572125

RESUMO

BACKGROUND AND AIMS: Upper GI-tracheobronchial fistula is a morbid condition with high mortality. It is a challenge for endoscopists because currently available treatments have severe limitations. In this study we assessed the efficacy and safety of an occluder we invented for endoscopic closure of refractory upper GI-tracheobronchial fistulas. METHODS: This was a prospective, single-arm, single-center trial conducted between September 2020 and March 2022. All patients undergoing occluder placement were eligible to enroll. The primary endpoints were clinical success rate (CSR) and complete closure rate (CCR) at 3 months and safety. Secondary efficacy endpoints were technical success rates, CSRs and CCRs at 1 and 6 months, near-complete closure rates, change from baseline in body mass index (BMI), and health-related quality of life (HRQoL) at 1, 3, and 6 months. RESULTS: Twenty-eight patients (mean age, 63.2 years; 23 men) were enrolled. Eighteen through-the-scope occluders (TTSOs) and 10 through-the-overtube occluders (TTOOs) were implanted, with a technical success rate of 100%. The mean procedure time for the TTSO and TTOO groups were 28.0 ± 8.0 minutes and 31.8 ± 7.7 minutes, respectively. The CSRs at 1, 3, and 6 months were 92.9%, 96.4%, and 92.0% and the CCRs were 60.7%, 60.7%, and 60.0%, respectively. The mean BMI at 3 and 6 months and HRQoL at 1, 3, and 6 months were significantly increased compared with baseline (P < .05). Two completely occluded fistulas had 1-sided or complete healing by coverage of granulation tissue and re-epithelialized mucosa at a follow-up of 6 and 12 months. All 14 adverse events were either mild and transient or easily corrected. CONCLUSIONS: Our clinical outcomes suggest that this novel GI occluder is a safe and effective salvage option for patients with refractory upper GI-tracheobronchial fistulas. (Clinical trial registration number: ChiCTR2000038566.).


Assuntos
Fístula , Qualidade de Vida , Masculino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Endoscopia , Resultado do Tratamento , Estudos Retrospectivos
5.
Inorg Chem ; 62(7): 3047-3055, 2023 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-36734972

RESUMO

The iconic W@Au12 icosahedral bare cluster reaches the favorable closed-shell superatomic electron configuration 1S2 1P6 1D10, making it an 18-cluster electron (18-ce) superatom. Here, we pursue the evaluation of a ligand-protected counterpart based on the construction of a fully phosphine-protected [W@Au12(dppm)6] cluster strongly related to the characterized [Au13(dppm)6]5+ homometallic counterpart. The later cluster has the same total number of valence electrons as the former but is considered an 8-ce superatom with 1S2 1P6 configuration. The fundamental differences between 8- and 18-ce species are investigated. The character of the frontier orbitals varies from 1P/1D in the 8-ce case to a 1D/ligand for 18-ce species, enabling an efficient charge transfer toward the ligands upon irradiation, being interesting for electron injection in optoelectronic devices and black absorbers applications. Excited-state properties are also revisited, showing different geometrical and electronic structure variations between 8- and 18-ce species. Moreover, the continuum between the 8- and 18-ce limits has been explored by varying the nature of the encapsulated dopant between group 6 and group 11. The transition between the 8- and 18-ce counts can be formally situated between Pt (8-ce) and Ir (18-ce). Thus, 18-ce derivatives obtained as doped counterparts of homometallic gold clusters can introduce useful alternatives to achieve different properties in related structural motifs, which can be further explored owing to their extension of the well-established versatility of current gold nanoclusters.

6.
Inorg Chem ; 62(26): 10185-10192, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37338814

RESUMO

The metallophilic properties, spherical configuration, and flexible coordination of silver ions make them prone to create various coordination modes and structural features. Therefore, with the increase of the complexities of self-assembly, the effect of various synthetic conditions in the final structure of silver compounds becomes diverse and attractive. In this study, two new silver polyclusters, 16- and 21-nuclearity, protected by multiple ligands including alkynyl, trifluoroacetate, and diphenylphosphinate, were synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and Fourier transform infrared (FTIR) spectroscopy. The optical properties and thermal stability of the polyclusters were studied by solid-state ultraviolet-visible (UV-vis) absorption and solid UV-vis diffuse reflectance spectra and gravimetric analysis, respectively. The formation of the two polyclusters can be fine-controlled by simply adjusting the stoichiometric ratio of diphenylphosphinate ligands to silver precursors under the same synthetic condition, leading to the different coordination modes between ligands and Ag centers. This work shows a facile and template-free method to synthesize and control the silver polycluster assembly, encouraging further development of new polyclusters with the potential for various applications.

7.
Phys Chem Chem Phys ; 25(27): 17901-17906, 2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37395071

RESUMO

Illustrating the molecular structure of metal nanoclusters with the protection of multiple ligands is a prerequisite to understand structure-property relationships of nano or bulk materials with hybrid interfaces. Reported herein is the synthesis, total structure and electronic structure analysis of a new Ag/Cu alloy nanocluster with triple-ligand protection. The cluster with the formula of Ag10Cu16(C8H9S)16(PPh3)4(CF3CO2)8 has been attained in one-pot in a simple way. X-ray single crystal analysis displays its unique metal framework and more importantly rich interface structures. The ligands of phosphine, thioate and carboxylic acid are coordinated to the surface of the cluster in distinctive modes. The electronic structure of the cluster has been revealed by density functional theory, showing that it is a 2-electron superatom with jellium configurations of 1S2. In good accordance with the closure of the geometric and electronic structures, the cluster exhibits moderate stability, which makes it a candidate for further application in many fields.

8.
Plant J ; 106(5): 1401-1413, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33745166

RESUMO

Naringenin, the biochemical precursor for predominant flavonoids in grasses, provides protection against UV damage, pathogen infection and insect feeding. To identify previously unknown loci influencing naringenin accumulation in rice (Oryza sativa), recombinant inbred lines derived from the Nipponbare and IR64 cultivars were used to map a quantitative trait locus (QTL) for naringenin abundance to a region of 50 genes on rice chromosome 7. Examination of candidate genes in the QTL confidence interval identified four predicted uridine diphosphate-dependent glucosyltransferases (Os07g31960, Os07g32010, Os07g32020 and Os07g32060). In vitro assays demonstrated that one of these genes, Os07g32020 (UGT707A3), encodes a glucosyltransferase that converts naringenin and uridine diphosphate-glucose to naringenin-7-O-ß-d-glucoside. The function of Os07g32020 was verified with CRISPR/Cas9 mutant lines, which accumulated more naringenin and less naringenin-7-O-ß-d-glucoside and apigenin-7-O-ß-d-glucoside than wild-type Nipponbare. Expression of Os12g13800, which encodes a naringenin 7-O-methyltransferase that produces sakuranetin, was elevated in the mutant lines after treatment with methyl jasmonate and insect pests, Spodoptera litura (cotton leafworm), Oxya hyla intricata (rice grasshopper) and Nilaparvata lugens (brown planthopper), leading to a higher accumulation of sakuranetin. Feeding damage from O. hyla intricata and N. lugens was reduced on the Os07g32020 mutant lines relative to Nipponbare. Modification of the Os07g32020 gene could be used to increase the production of naringenin and sakuranetin rice flavonoids in a more targeted manner. These findings may open up new opportunities for selective breeding of this important rice metabolic trait.


Assuntos
Flavanonas/metabolismo , Flavonoides/metabolismo , Glucosiltransferases/metabolismo , Gafanhotos/fisiologia , Hemípteros/fisiologia , Oryza/genética , Doenças das Plantas/imunologia , Acetatos/metabolismo , Animais , Mapeamento Cromossômico , Ciclopentanos/metabolismo , Glucosiltransferases/genética , Metiltransferases/genética , Metiltransferases/metabolismo , Oryza/enzimologia , Oryza/imunologia , Oryza/parasitologia , Oxilipinas/metabolismo , Melhoramento Vegetal , Doenças das Plantas/parasitologia , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Locos de Características Quantitativas/genética
9.
Inorg Chem ; 61(23): 8623-8628, 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35640274

RESUMO

The controlled structural modification of ligand-protected gold clusters is evaluated by a proper variation of the size and shape of N-heterocyclic carbene (NHC) ligands. Density functional theory calculations show that the Au13 core of [Au13(NHC)8Br4]+ can be shaped into an icosahedron and/or a so far unexpected cuboctahedron depending on the sterical effect inferred by the NHC ligand side arms. As a result, the cluster properties can be modified, encouraging further exploration on controlled core isomerization in ligated gold cluster chemistry.

10.
J Phys Chem A ; 126(4): 536-545, 2022 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-35044183

RESUMO

Atomically precise gold nanoclusters (AuNCs) belong to a relevant area offering useful templates with tunable properties toward functional nanostructures. In this work, we explored the feasible incorporation of N-heterocyclic carbenes (NHCs), as part of the protecting-ligand shell in AuNCs. Our results, which are based on the substitution of phosphine ligands in experimentally characterized AuNCs by NHCs in various eight-electron superatoms Au13 and M4Au9 (M = Cu, Ag), indicate similar electronic structure and stability but somewhat different optical properties. These findings support the feasible obtention of novel targets for explorative synthetic efforts featuring NHC ligands on medium-sized species based on the recurrent Au13 icosahedral core. The hypothetical species appear to be interesting templates for building blocks in nanostructured materials with tuned properties, which encourage experimental exploration of ligand versatility in homo- and heterometallic superatomic clusters.

11.
Inorg Chem ; 60(11): 8173-8180, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34033476

RESUMO

The development of well-defined atomically precise heteronuclear nanoclusters passivated by protecting ligands is presently a booming area, owing to the fact that doping well-known homonuclear nanostructures allows fine-tuning of their properties. Here, we explore by means of density functional theory calculations the possibility of doping the central gold atom in the classical [Au13(dppe)5Cl2]3+cluster (1) by Os. Although both [Au13(dppe)5Cl2]3+ and [Os@Au12(dppe)5Cl2] have the same total number of electrons, we show that they are not isoelectronic within the formalism of the superatom model, being respectively an 8- and an 18-electron species. It results that they exhibit similar structures but present significantly different optical behaviors (ultraviolet/visible and circular dichroism). Similar results are obtained for the Ru and Fe relatives. Emission properties indicate some redshift of the T1→S1 decay with respect to [Au13(dppe)5Cl2]3+, involving an equatorial distortion of the Au12Cl2 core in the T1 state, rather than the axial distortion afforded by 1. The sizable highest occupied molecular orbital-lowest unoccupied molecular orbital gaps found for the three doped species suggest that further experimental exploration of different stable doped species derived from the ligand-protected Au12Cl2 core should be encouraged.

12.
Chemistry ; 26(24): 5508-5514, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32045497

RESUMO

The electronic structure of the spherical Mackay icosahedral nanosized cluster Pd55 (PiPr3 )12 (µ3 -CO)20 is analyzed by using DFT calculations. Results reveal that it can be considered as a regular superatom with a "magic" electron count of 20, characterized by a 1S2 1P6 1D10 2S2 jellium configuration. Its open shell nature is associated with partial occupation of non-jellium, 4d-type, levels located on the interior of the Pd55 kernel. This shows that the superatom model can be used to rationalize the bonding and stability of spherical ligated group 10 clusters, despite their apparent 0-electron count.

13.
Inorg Chem ; 59(20): 15240-15249, 2020 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-33021784

RESUMO

The structure and bonding of a series of selected phosphine-protected gold clusters (Aun-P) of nuclearity varying from n = 6 to 13 were investigated by density functional theory (DFT) calculations and compared to those of the hypothetical homologues in which phosphines were replaced by N-heterocyclic carbene (NHC) analogues (Aun-C). Both the Aun-P and Aun-C series exhibit similar stabilities and structural features, except for n = 6, where some differences are noted. The NHC ligands are found to be even slightly more strongly bonded to the gold core (by a few kilocalories per mole per ligand) than phosphines. Investigation of the optical properties of both series using time-dependent DFT calculations indicates similarities in the nature and energies of the UV-vis optical transitions and, consequently, relatively similar shapes of the simulated spectra, with a general blue-shift tendency when going from Aun-P to Aun-C. The fluorescence behavior observed experimentally for some of the Aun-P species is expected to occur also for their Aun-C analogues, which can be extended to other carbene-ligand-protected nanoclusters. Our results show that it should be possible to stabilize gold clusters with NHC ligands, in relation to the seminal Au13-ligand-protected core, offering novel building blocks for the design of nanostructured materials with various properties.

14.
Molecules ; 20(1): 1676-85, 2015 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-25608855

RESUMO

In order to find and develop new botanical pesticides against tobacco storage pests, bioactivity screening was performed. The essential oil obtained from the aerial parts of Liriope muscari was investigated by GC/MS and GC/FID. A total of 14 components representing 96.12% of the oil were identified and the main compounds in the oil were found to be methyl eugenol (42.15%) and safrole (17.15%), followed by myristicin (14.18%) and 3,5-dimethoxytoluene (10.60%). After screening, the essential oil exhibit potential insecticidal activity. In the progress of assay, it showed that the essential oil exhibited potent contact toxicity against Tribolium castaneum, Lasioderma serricorne and Liposcelis bostrychophila adults, with LD50 values of 13.36, 11.28 µg/adult and 21.37 µg/cm2, respectively. The essential oil also exhibited strong repellency against the three stored product insects. At the same concentrations, the essential oil was more repellent to T. castaneum than to L. serricorne adults. The results indicate that the essential oil of Liriope muscari has potential to be developed into a natural insecticide or repellent for controlling insects in stored tobacco and traditional Chinese medicinal materials.


Assuntos
Besouros/efeitos dos fármacos , Repelentes de Insetos/toxicidade , Liriope (Planta)/química , Nicotiana/parasitologia , Óleos Voláteis/toxicidade , Controle Biológico de Vetores , Animais , Óleos Voláteis/química
15.
Molecules ; 20(12): 21939-45, 2015 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-26670226

RESUMO

The essential oil obtained by hydrodistillation from Alpinia kwangsiensis rhizomes was investigated by GC-MS. A total of 31 components representing 92.45% of the oil were identified and the main compounds in the oil were found to be camphor (17.59%), eucalyptol (15.16%), ß-pinene (11.15%) and α-pinene (10.50%). These four compounds were subsequently isolated and the essential oil and four isolated compounds exhibited potent insecticidal activity against Lasioderma serricorne adults. During the assay, it was shown that the essential oil exhibited both potential contact (LD50 = of 24.59 µg/adult) and fumigant (LC50 = of 9.91 mg/L air) toxicity against Lasioderma serricorne. The study revealed that the insecticidal activity of the essential oil can be attributed to the synergistic effects of its diverse major components, which indicates that oil of Alpinia kwangsiensis and its isolated compounds have potential to be developed into natural insecticides to control insects in stored grains and traditional Chinese medicinal materials.


Assuntos
Alpinia/química , Besouros/efeitos dos fármacos , Inseticidas/química , Inseticidas/farmacologia , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Rizoma/química , Animais , Cromatografia Gasosa-Espectrometria de Massas , Inseticidas/isolamento & purificação , Óleos Voláteis/isolamento & purificação
16.
Dalton Trans ; 53(36): 15190-15197, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39221584

RESUMO

Copper nanoclusters have attracted significant interest in the field of materials science due to their high abundance, complex structure, and unique properties. However, there is a limited amount of research on the relationship between structure and properties. In this study, we synthesized and comprehensively characterized two new Cu9 nanoclusters, [Cu9(PhSe)6(PPh2O2)3] (Cu9-1) and [Cu9(CH3OPhS)6(PPh2O2)3] (Cu9-2), in order to investigate the effect of ligands on photoluminescence. Both clusters have the same metal skeleton and similar distribution of ligands, with the only difference being the surface ligands (PhSe vs. CH3OPhS). Interestingly, the photoluminescence lifetime of Cu9-2 was found to be 3.2 times longer than that of Cu9-1. Furthermore, a notable Stokes shift (ST) was observed in the emission spectra of the two clusters. Single-crystal X-ray analysis revealed the formation of hydrogen bonds between neighboring clusters of Cu9-2, which influenced intramolecular interactions. Additionally, the methoxy groups in Cu9-2, acting as conjugated electron donors, promoted intramolecular charge transfer and π-π interaction. This study is expected to inspire further research on surface ligand engineering for controlling the properties of copper nanoclusters beyond photoluminescence.

17.
Dalton Trans ; 53(40): 16740-16746, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39347686

RESUMO

Low-valent palladium nanoparticles are efficient species promoting catalytic activity and selectivity in a number of chemical reactions. Recently, an atom-centered cuboctahedral Pd13 motif has been characterized as a ligand-protected [Pd13(Tr)6]2+ cluster featuring a 1s2 superatomic shell structure. In this report, we describe the ligand-cluster of and endohedral-cage interaction in [Pd13(Tr)6]2+, which accounts for a favorable situation in the overall cluster. In addition, the spherical aromatic properties of the cluster were evaluated to understand the behavior of the ligand-protected Pd13 cluster core. Our results indicate a sizable interaction towards carbon-based ligands in an overall spherical aromatic cluster featuring a long-range shielding cone. Thus, [Pd13(Tr)6]2+ is rationalized as the first ligand-protected palladium cluster to date exhibiting spherical aromatic properties, serving as a stable building block for molecule-based materials or as a dopant in porous carbon materials.

18.
Sci Rep ; 14(1): 9277, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38653787

RESUMO

Crop disease detection and crop baking stage judgement require large image data to improve accuracy. However, the existing crop disease image datasets have high asymmetry, and the poor baking environment leads to image acquisition difficulties and colour distortion. Therefore, we explore the potential of the self-attention mechanism on crop image datasets and propose an innovative crop image data-enhancement method for recurrent generative adversarial networks (GANs) fused with the self-attention mechanism to significantly enhance the perception and information capture capabilities of recurrent GANs. By introducing the self-attention mechanism module, the cycle-consistent GAN (CycleGAN) is more adept at capturing the internal correlations and dependencies of image data, thus more effectively capturing the critical information among image data. Furthermore, we propose a new enhanced loss function for crop image data to optimise the model performance and meet specific task requirements. We further investigate crop image data enhancement in different contexts to validate the performance and stability of the model. The experimental results show that, the peak signal-to-noise ratio of the SM-CycleGAN for tobacco images and tea leaf disease images are improved by 2.13% and 3.55%, and the structural similarity index measure is improved by 1.16% and 2.48% compared to CycleGAN, respectively.

19.
Front Microbiol ; 14: 1296916, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38075935

RESUMO

Introduction: Tobacco black shank is a devastating soil-borne disease caused by the oomycete Phytophthora nicotianae, severely hamper tobacco production worldwide. However, the synergistic effect of biocontrol bacteria and marine polysaccharides/oligosaccharides on tobacco black shank control was few documented. Methods: In this study, Bacillus amyloliquefaciens CAS02 (CAS02) and chitooligosaccharide (COS) were screened firstly, and their synergistic antagonistic effect against P. nicotianae and the underlying mechanism were investigated in vitro and in vivo. Results: In vitro experiments showed that, compared with the application of CAS02 or COS alone, co-application of CAS02 and COS significantly increased the inhibition rate against P. nicotianae by 11.67% and 63.31%, respectively. Furthermore, co-application of CAS02 and COS disrupted the structure of mycelia to a greater extent. The co-application of CAS02 and COS showed synergistic effect, with the relative control effect maintained above 60% during the 60-day pot experiment, significantly higher than that of application CAS02 or COS alone. The combined application of CAS02 and COS reduced the relative abundance of P. nicotianae in the rhizosphere soil and increased the relative abundance of bacterial taxa potentially involved in disease suppression, such as Nocardioides, Devosia and Bradyrhizobium. Meanwhile, CAS02 and COS synergistically activated salicylic acid (SA), ethylene (ET), and hypersensitive response (HR) defense signaling pathways in tobacco plants. Discussion: Our findings demonstrate that co-application of CAS02 and COS remarkably improve the relative control effect against tobacco black shank through multiple pathways and provide a promising strategy for the efficient green control of tobacco black shank.

20.
Pol J Microbiol ; 72(1): 47-60, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36929894

RESUMO

For decades chlorine dioxide has been used in water disinfection with excellent results. As the scope of application expands, chlorine dioxide has the potential for soil disinfection. We used amplicon sequencing and gas chromatography-mass spectrometry to compare the changes of four mixed rhizosphere microbial community samples and 12 tobacco leaf volatile samples four months after the flood irrigation with chlorine dioxide in different concentrations (0, 2, 4, 8 mg/l). Phenotypic data of 60 tobacco plants were also collected. The effects of chlorine dioxide on rhizosphere microorganisms were positively correlated with dose gradients. Bacteria responded more strongly in both community structure and metabolic pathways than fungi. Five new bacterial phyla (Firmicutes, Bacteroidota, Myxococcota, Patescibacteria, Verrucomicroboata) appeared in chlorine dioxide treatment groups, while the fungal community only appeared as one new fungal phylum (Basidomycota). Alterations in 271 predicted metabolic bacterial pathways were found. However, in the fungal community were only 10 alternations. The correlations between leaf volatile compounds and rhizosphere microorganisms under the influence of chlorine dioxide treatment could be observed based on network results. However, natural connectivity had already been declining rapidly when less than 20% of the network's nodes were removed. Therefore, the microbe-metabolite network is not stable. It might be why chlorine dioxide treatments did not significantly affect tobacco quality (p = 0.754) and phenotype (p = 0.867). As a comprehensive investigation of chlorine dioxide in agriculture, this study proves the effectiveness and safety of chlorine dioxide soil disinfection and widens the application range of chlorine dioxide.


Assuntos
Microbiota , Nicotiana , Rizosfera , Bactérias/genética , Solo/química , Microbiologia do Solo , Raízes de Plantas/microbiologia , Fungos/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA