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1.
Small ; 20(9): e2305490, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37852940

RESUMO

Accumulation of reactive oxygen species (ROS) in periodontitis exacerbates the destruction of alveolar bone. Therefore, scavenging ROS to reshape the periodontal microenvironment, alleviate the inflammatory response and promote endogenous stem cell osteogenic differentiation may be an effective strategy for treating bone resorption in periodontitis. In this study, sericin-hydroxyapatite nanoparticles (Se-nHA NPs) are synthesized using a biomimetic mineralization method. Se-nHA NPs and proanthocyanidins (PC) are then encapsulated in sericin/sodium alginate (Se/SA) using an electrostatic injection technique to prepare Se-nHA/PC microspheres. Microspheres are effective in scavenging ROS, inhibiting the polarization of macrophages toward the M1 type, and inducing the polarization of macrophages toward the M2 type. In normal or macrophage-conditioned media, the Se-nHA/PC microspheres effectively promoted the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). Furthermore, the Se-nHA/PC microspheres demonstrated anti-inflammatory effects in a periodontitis rat model by scavenging ROS and suppressing pro-inflammatory cytokines. The Se-nHA/PC microspheres are also distinguished by their capacity to decrease alveolar bone loss, reduce osteoclast activity, and boost osteogenic factor expression. Therefore, the biomimetic Se-nHA/PC composite microspheres have efficient ROS-scavenging, anti-inflammatory, and osteogenic abilities and can be used as a multifunctional filling material for inflammatory periodontal tissue regeneration.


Assuntos
Periodontite , Proantocianidinas , Sericinas , Humanos , Animais , Ratos , Osteogênese , Biomimética , Microesferas , Espécies Reativas de Oxigênio , Regeneração Óssea , Periodontite/terapia , Durapatita , Anti-Inflamatórios
2.
Chem Res Toxicol ; 37(1): 42-56, 2024 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-38091573

RESUMO

The chemokine receptor CXCR3 is functionally pleiotropic, not only recruiting immune cells to the inflamed liver but also mediating the pathological process of cholestatic liver injury (CLI). However, the mechanism of its involvement in the CLI remains unclear. Both alpha-naphthylisothiocyanate (ANIT) and triptolide are hepatotoxicants that induce CLI by bile acid (BA) dysregulation, inflammation, and endoplasmic reticulum (ER)/oxidative stress. Through molecular docking, CXCR3 is a potential target of ANIT and triptolide. Therefore, this study aimed to investigate the role of CXCR3 in ANIT- and triptolide-induced CLI and to explore the underlying mechanisms. Wild-type mice and CXCR3-deficient mice were administered with ANIT or triptolide to compare CLI, BA profile, hepatic recruitment of IFN-γ/IL-4/IL-17+CD4+T cells, IFN-γ/IL-4/IL-17+iNKT cells and IFN-γ/IL-4+NK cells, and the expression of ER/oxidative stress pathway. The results showed that CXCR3 deficiency ameliorated ANIT- and triptolide-induced CLI. CXCR3 deficiency alleviated ANIT-induced dysregulated BA metabolism, which decreased the recruitment of IFN-γ+NK cells and IL-4+NK cells to the liver and inhibited ER stress. After triptolide administration, CXCR3 deficiency ameliorated dysregulation of BA metabolism, which reduced the migration of IL-4+iNKT cells and IL-17+iNKT cells and reduced oxidative stress through inhibition of Egr1 expression and AKT phosphorylation. Our findings suggest a detrimental role of CXCR3 in ANIT- and triptolide-induced CLI, providing a promising therapeutic target and introducing novel mechanisms for understanding cholestatic liver diseases.


Assuntos
1-Naftilisotiocianato , Colestase , Diterpenos , Fenantrenos , Animais , Camundongos , 1-Naftilisotiocianato/toxicidade , 1-Naftilisotiocianato/metabolismo , Interleucina-17/toxicidade , Interleucina-17/metabolismo , Interleucina-17/uso terapêutico , Interleucina-4/toxicidade , Interleucina-4/metabolismo , Interleucina-4/uso terapêutico , Simulação de Acoplamento Molecular , Fígado/metabolismo , Colestase/induzido quimicamente , Ácidos e Sais Biliares , Compostos de Epóxi
3.
J Acoust Soc Am ; 156(1): 359-368, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38994905

RESUMO

A noise attenuation performance test was conducted on earmuffs using a recoilless weapon launch platform in a confined space, along with two acoustic test fixtures (ATFs). The overpressure at the ATF's effective tympanic membrane comprised direct sound at 185 dB sound pressure level (SPL) and reflected sound at 179 dB SPL. Wearing earmuffs reduced these peaks to 162 dB SPL and 169 dB SPL, respectively. The reflected sound from walls was defined as delayed sound. An analytical model for earmuff noise attenuation simulated their effectiveness. The simulation revealed that when the earmuffs attenuated delayed sound, the acoustic impedance of acoustic leakage and the acoustic impedance of the earmuff material decreased by 96% and 50%, respectively. The negative overpressure zone between direct and delayed sound decreased the earmuffs' fit against the ATF. Additionally, the enclosed volume between the earmuff and the ear canal decreased by 12%. After the installation of bandages on the earmuffs, the overpressure peak of delayed sound was reduced by 5 dB. Furthermore, the acoustic impedance of the earmuff's sound leakage path and the acoustic impedance of the earmuff material deformation path increased by 100% and 809%, respectively.


Assuntos
Acústica , Dispositivos de Proteção das Orelhas , Pressão , Humanos , Desenho de Equipamento , Ruído , Som , Armas de Fogo , Adulto , Masculino , Fatores de Tempo , Modelos Teóricos
4.
Molecules ; 29(14)2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39064941

RESUMO

A novel axially chiral all-hydrocarbon cyclo[7] (1,3-(4,6-dimethyl)benzene (CDMB-7) was designed and synthesized using atroposelective[2 + 5] cyclization through Suzuki-Miyaura coupling. CDMB-7 adopts an irregular bowl-like shape with C2 symmetry and exhibits two diastereoisomers in its crystallographic structure. The conformational isomers of CDMB-7 racemates remain stable at high temperatures (393 K). High-performance liquid chromatography (HPLC) confirmed that a single chiral isomer will spontaneously undergo racemization within 30 min at room temperature. This finding opens up possibilities for achieving adaptive chirality in all-hydrocarbon cyclo[7] m-benzene macrocycles.

5.
J Gene Med ; 25(5): e3481, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36782035

RESUMO

BACKGROUND: Osteoporosis (OP) is a metabolic bone disease involving reduced bone mass. Adipose-derived stem cells (ASCs) play an important role in bone regeneration. Emerging evidence suggests that methyltransferase-like 3 (METTL3) plays a significant role in bone development and metabolism. Therefore, this study investigates changes to METTL3 in the osteogenic differentiation of adipose stem cells in osteoporotic rats (OP-ASCs) and explores ways to enhance their osteogenic ability. METHODS: An animal model of osteoporosis was established by removing both ovaries in rats. Real-time PCR and western blotting were performed to detect the expression of METTL3 and bone-related molecules, including runt-related transcription factor 2 (Runx2) and osteopontin (Opn). Furthermore, alkaline phosphatase staining was used to confirm the osteogenic potential of stem cells. Mettl3 small interfering RNA and Mettl3 overexpression lentivirus were used to assess the role of METTL3 in osteogenic differentiation of ASCs and OP-ASCs. RESULTS: The osteogenic differentiation capacity and Mettl3 expression significantly decreased in OP-ASCs. Moreover, Mettl3 silencing down-regulated the osteogenic ability of ASCs, and overexpression of Mettl3 recovered the impaired osteogenic capacity in OP-ASCs in vitro. CONCLUSION: The Mettl3 expression levels and osteogenic potential of OP-ASCs decreased. However, overexpression of METTL3 rescued the osteogenic ability of OP-ASCs, providing a new target for treatment of osteoporotic bone defects.


Assuntos
Osteogênese , Osteoporose , Ratos , Animais , Tecido Adiposo , Diferenciação Celular , Células-Tronco , Osteoporose/metabolismo , Metiltransferases , Células Cultivadas
6.
Small ; 19(8): e2206400, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36504297

RESUMO

The fast electrochemical kinetics behavior and long cycling life have been the goals in developing anode materials for potassium ion batteries (PIBs). On account of high electron conductivity and theoretical capacity, transition metal selenides have been deemed as one of the promising anode materials for PIBs. Herein, a systematic structural manipulation strategy, pertaining to the confine of Fe3 Se4 particles by 3D graphene and the dual phosphorus (P) doping to the Fe3 Se4 /3DG (DP-Fe3 Se4 /3DG), has been proposed to fulfill the efficient potassium-ion (K-ion) evolution kinetics and thus boost the K-ion storage performance. The theoretical calculation results demonstrate that the well-designed dual P doping interface can effectively promote K-ion adsorption behavior and provide a low energy barrier for K-ion diffusion. The insertion-conversion and adsorption mechanism for multi potassium storage behavior in DP-Fe3 Se4 /3DG composite has been also deciphered by combining the in situ/ex situ X-ray diffraction and operando Raman spectra evidences. As expected, the DP-Fe3 Se4 /3DG anode exhibits superior rate capability (120.2 mA h g-1 at 10 A g-1 ) and outstanding cycling performance (157.9 mA h g-1 after 1000 cycles at 5 A g-1 ).

7.
Small ; 19(37): e2301738, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37140103

RESUMO

A drawback with lithium-ion batteries (LIBs) lies in the unstable lithium storage which results in poor electrochemical performance. Therefore, it's of importance to improve the electrochemical functionality and Li-ion transport kinetics of electrode materials for high-performance lithium storage. Here, a subtle atom engineering via injecting molybdenum (Mo) atoms into vanadium disulfide (VS2 ) to boost high capacity Li-ion storage is reported. By combining operando, ex situ monitoring and theoretical simulation, it is confirmed that the 5.0%Mo atoms impart flower-like VS2 with expanded interplanar spacing, lowered Li-ion diffusion energy barrier, and increased Li-ion adsorption property, together with enhanced e- conductivity, to boost Li-ion migration. A "speculatively" optimized 5.0% Mo-VS2 cathode that exhibits a specific capacity of 260.8 mA h g-1 at 1.0 A g-1 together with a low decay of 0.009% per cycle over 500 cycles is demonstrated. It is shown that this value is ≈1.5 times compared with that for bare VS2 cathode. This investigation has substantiated the Mo atom doping can effectively guide the Li-ion storage and open new frontiers for exploiting high-performance transition metal dichalcogenides for LIBs.

8.
J Nanobiotechnology ; 21(1): 266, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37563585

RESUMO

Bacterial infections can significantly impede wound healing and pose a serious threat to the patient's life. The excessive use of antibiotics to combat bacterial infections has led to the emergence of multi-drug-resistant bacteria. Therefore, there is a pressing need for alternative approaches, such as photothermal therapy (PTT), to address this issue. In this study, for the first time, CuS NPs with photothermal properties were synthesized using sericin as a biological template, named CuS@Ser NPs. This method is simple, green, and does not produce toxic and harmful by-products. These nanoparticles were incorporated into a mixture (XK) of xanthan gum and konjac glucomannan (KGM) to obtain XK/CuS NPs composite hydrogel, which could overcome the limitations of current wound dressings. The composite hydrogel exhibited excellent mechanical flexibility, photothermal response, and biocompatibility. It also demonstrated potent antibacterial properties against both Gram-positive and negative bacteria via antibacterial experiments and accelerated wound healing in animal models. Additionally, it is proved that the hydrogel promoted tissue regeneration by stimulating collagen deposition, angiogenesis, and reducing inflammation. In summary, the XK/CuS NPs composite hydrogel presents a promising alternative for the clinical management of infected wounds, offering a new approach to promote infected wound healing.


Assuntos
Infecções Bacterianas , Hidrogéis , Animais , Hidrogéis/farmacologia , Cicatrização , Antibacterianos/farmacologia , Colágeno
9.
Yi Chuan ; 45(7): 617-623, 2023 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-37503585

RESUMO

Infantile neuroaxonal dystrophy (INAD) is a rare autosomal recessive neurodegenerative disease characterized by early hypotonia, and rapid progression to psychomotor development regression, pyramidal tract positivity, and spastic quadriplegia. In this report, we describe a Chinese patient with INAD who presented with hypotonia, delayed motor and language development, and subsequently improved with rehabilitation training. Genetic testing revealed that the patient had compound heterozygous PLA2G6 gene variants, with the heterozygous c.496dupG (p.Glu166fsTer32) variant inherited from her father and the heterozygous c.2189T>G (p.Met730Arg) variant inherited from her mother. The p.Met730Arg was a novel variant. The protein structure predicts that the structural stability of the mutant protein may change, and the in vivo experimental results show that the expression of the mutant protein decrease. This study enriches the PLA2G6 gene mutation spectrum, and improves the clinicians' diagnostic awareness of INAD.


Assuntos
Distrofias Neuroaxonais , Doenças Neurodegenerativas , Humanos , Criança , Feminino , Doenças Neurodegenerativas/genética , Hipotonia Muscular/genética , Testes Genéticos , Mutação , Distrofias Neuroaxonais/genética
10.
Appl Opt ; 60(13): 3779-3783, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33983311

RESUMO

Based on our previous research on optical needles with arbitrary three-dimensional (3D) polarization, we investigate the relationship between the electric field and spin angular momentum (SAM). We have realized optical needles with arbitrary 3D spin-orientation and SAM per photon. To our best knowledge, it is the first time to obtain optical needles whose SAM can be customized on both direction and size. The relative error between the obtained spin and customized spin is always less than 5% even if SAM per photon is very small.

11.
Int J Mol Sci ; 20(19)2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31569598

RESUMO

The interests of developing antimicrobial biomaterials based on silk sericin from Bombyx mori cocoon, have been shooting up in the last decades. Sericin is a valuable natural protein owing to its hydrophilicity, biodegradability, and biocompatibility. Here, we fabricated a sponge with antibacterial capacities for potential wound dressing application. By co-blending of sericin, polyvinyl alcohol (PVA) and zinc oxide nanoparticles (ZnONPs), the ZnONPs-sericin/PVA composite sponge (ZnONPs-SP) was successfully prepared after freeze-drying. Scanning electron microscopy showed the porous structure of ZnONPs-SP. Energy dispersive spectroscopy indicated the existence of Zn in the sponge. X-ray diffractometry revealed the hexagonal wurtzite structure of ZnONPs. Fourier transform infrared spectroscopy showed the biologic coupling of ZnONPs and sericin resulted in a decrease of α-helix and random coil contents, and an increase of ß-sheet structure in the sponge. The swelling experiment suggested ZnONPs-SP has high porosity, good hydrophilicity, and water absorption capability. The plate bacterial colony counting coupled with growth curve assays demonstrated that the composite sponge has an efficiently bacteriostatic effect against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, the cell compatibility analysis suggested the composite sponge has excellent cytocompatibility on NIH3T3 cells. In all, ZnONPs-SP composite sponge has significant potentials in biomaterials such as wound dressing and tissue engineering.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Nanopartículas Metálicas/química , Polivinil/química , Polivinil/farmacologia , Sericinas/química , Óxido de Zinco/química , Animais , Bombyx/química , Sobrevivência Celular , Nanopartículas Metálicas/ultraestrutura , Camundongos , Testes de Sensibilidade Microbiana , Células NIH 3T3 , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
12.
Molecules ; 24(3)2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30704137

RESUMO

Silk sericin (SS) is a type of natural macromolecular protein with excellent hydrophilicity, biocompatibility and biodegradability, but also has very poor mechanical properties. To develop sericin-based wound dressings, we utilized polyvinyl alcohol (PVA) to reinforce the mechanical property of sericin by blending PVA and sericin, then modified zinc oxide nanoparticles (ZnO NPs) on SS/PVA film with the assistance of polydopamine (PDA) to endow SS/PVA film with antibacterial activity. Scanning electron microscopy, energy dispersive spectroscopy and X-ray powder diffraction demonstrated ZnO NPs were well grafted on PDA-SS/PVA film. Fourier transform infrared spectra suggested PDA coating and ZnONPs modification did not alter the structure of sericin and PVA. Water contact angle and swelling tests indicated the excellent hydrophilicity and swellability of ZnO NPs-PDA-SS/PVA composite film. Mass loss analysis showed ZnO NPs-PDA-SS/PVA film had excellent stability. The mechanical performance test suggested the improved tensile strength and elongation at break could meet the requirement of ZnO NPs-PDA-SS/PVA film in biomaterial applications. The antibacterial assay suggested the prepared ZnO NPs-PDA-SS/PVA composite film had a degree of antimicrobial activity against Escherichia coli and Staphylococcus aureus. The excellent hydrophilicity, swellability, stability, mechanical property and antibacterial activity greatly promote the possibility of ZnO NPs-PDA-SS/PVA composite film in antibacterial biomaterials application.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Indóis/química , Nanopartículas/química , Polímeros/química , Álcool de Polivinil/química , Sericinas/química , Óxido de Zinco/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
13.
Molecules ; 24(4)2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30781833

RESUMO

Enzymatic activity assays are essential and critical for the study of enzyme kinetics. Adenylate kinase (Adk) plays a fundamental role in cellular energy and nucleotide homeostasis. To date, assays based on different principles have been used for the determination of Adk activity. Here, we show a spectrophotometric analysis technique to determine Adk activity with bromothymol blue as a pH indicator. We analyzed the effects of substrates and the pH indicator on the assay using orthogonal design and then established the most optimal assay for Adk activity. Subsequently, we evaluated the thermostability of Adk and the inhibitory effect of KCl on Adk activity with this assay. Our results show that this assay is simple, rapid, and precise. It shows great potential as an alternative to the conventional Adk activity assay. Our results also suggest that orthogonal design is an effective approach, which is very suitable for the optimization of complex enzyme reaction conditions.


Assuntos
Adenilato Quinase/química , Espectrofotometria/métodos , Azul de Bromotimol/química , Homeostase , Concentração de Íons de Hidrogênio , Cinética , Fosforilação , Cloreto de Potássio/química
14.
Biochem Biophys Res Commun ; 502(2): 250-254, 2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-29803677

RESUMO

Adenosine kinase (ADK) plays an important role in the growth and development of organisms. A convenient, quick, reliable, sensitive and low-cost assay for ADK activity is of great significance. Here, we found the reaction system with bromothymol blue as the pH indicator had a maximum absorption peak at 614 nm. The absorbance change in 614 nm was positively correlated with the generated hydrogen ions in the reaction catalyzed by ADK. Then, we demonstrated this assay was feasible for ADK activity. Further, we analyzed the effects of buffer, bromothymol blue concentrations on the sensitivity of the assay, and investigated the sensitivity of ADK contents and adenosine concentration on the assay. Finally, we calculated the Km and Vmax of ADK from Bombyx mori with this assay. Our results suggested this assay was quick, convenient, reliable, sensitive and economic for the activity of ADK. It is an excellent alternative for the conventional ADK assays.


Assuntos
Adenosina Quinase/análise , Colorimetria/métodos , Adenosina Quinase/química , Adenosina Quinase/metabolismo , Animais , Bombyx/enzimologia , Azul de Bromofenol , Azul de Bromotimol , Soluções Tampão , Colorimetria/estatística & dados numéricos , Corantes , Estudos de Viabilidade , Concentração de Íons de Hidrogênio , Cinética , Espectrofotometria
15.
Int J Mol Sci ; 19(10)2018 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-30248951

RESUMO

Silver nanoparticles (AgNPs) are extensively applied for their broad-spectrum and excellent antibacterial ability in recent years. Polydopamine (PDA) has great advantages for synthesizing large amounts of AgNPs, as it has multiple sites for silver ion binding and phenolic hydroxyl structure to reduce silver ions to AgNPs. Here, we mixed sericin and agar solution and dried at 65 °C to prepare a sericin (SS)/Agar composite film, and then coated polydopamine (PDA) on the surface of SS/Agar film by soaking SS/Agar film into polydopamine solution, subsequently synthesizing high-density AgNPs with the assistance of PDA to yield antibacterial AgNPs-PDA- SS/Agar film. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectra indicated the successful synthesis of high-density AgNPs on the surface of PDA-SS/Agar film. PDA coating and AgNPs modification did not affect the structure of sericin and agar. Furthermore, water contact angle, water absorption and mechanical property analysis showed that AgNPs-PDA-SS/Agar film had excellent hydrophilicity and proper mechanical properties. Inhibition zone and growth curve assays suggested the prepared film had excellent and long-lasting antibacterial ability. In addition, it had excellent cytocompatibility on the fibroblast NIH/3T3 cells. The film shows great potential as a novel kind of wound dressing.


Assuntos
Indóis/química , Nanopartículas Metálicas/química , Polímeros/química , Sericinas/química , Prata/química , Ágar/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Indóis/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Células NIH 3T3 , Polímeros/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Molhabilidade , Difração de Raios X
16.
Molecules ; 23(7)2018 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-30041405

RESUMO

Silk sericin is a protein from a silkworm's cocoon. It has good biocompatibility, hydrophilicity, bioactivity, and biodegradability. However, sericin could not be used in biomedical materials directly because of its frangible characteristic. To develop multifunctional sericin-based materials for biomedical purposes, we prepared a sericin/agar (SS/agar) composite film through the blending of sericin and agar and repetitive freeze-thawing. Then, we synthesized silver nanoparticles (AgNPs) in situ on the surface of the composite film to endow it with antibacterial activity. Water contact angle, swelling and losing ratio, and mechanical properties analysis indicated that the composite film had excellent mechanical property, hydrophilicity, hygroscopicity, and stability. Scanning electron microscopy and X-ray photoelectron spectroscopy analysis confirmed the successful modification of AgNPs on the composite film. X-ray powder diffraction showed the face-centered cubic structures of the AgNPs. This AgNPs modified composite film exhibited an excellent antibacterial capability against Escherichia coli and Staphylococcus aureus. Our study develops a novel AgNPs/sericin/agar composite film with enhanced mechanical performance and an antimicrobial property for potential biomedical applications.


Assuntos
Ágar/química , Antibacterianos/química , Antibacterianos/farmacologia , Fenômenos Mecânicos , Sericinas/química , Prata/química , Testes de Sensibilidade Microbiana , Nanocompostos/química , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Molhabilidade , Difração de Raios X
17.
Int J Syst Evol Microbiol ; 67(5): 1177-1184, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28073398

RESUMO

Arbuscular mycorrhizal fungi (AMF, subphylum Glomeromycotina) are symbionts of most terrestrial plants. They commonly harbour endobacteria of a largely unknown biology, referred to as MRE (Mollicutes/mycoplasma-related endobacteria). Here, we propose to accommodate MRE in the novel genus 'Candidatus Moeniiplasma.' Phylogeny reconstructions based on the 16S rRNA gene sequences cluster 'Ca.Moeniiplasma' with representatives of the class Mollicutes, whereas phylogenies derived from amino acid sequences of 19 genes indicate that it is a discrete lineage sharing ancestry with the members of the family Mycoplasmataceae. Cells of 'Ca.Moeniiplasma' reside directly in the host cytoplasm and have not yet been cultivated. They are coccoid, ~500 nm in diameter, with an electron-dense layer outside the plasma membrane. However, the draft genomes of 'Ca.Moeniiplasma' suggest that this structure is not a Gram-positive cell wall. The evolution of 'Ca.Moeniiplasma' appears to be driven by an ultrarapid rate of mutation accumulation related to the loss of DNA repair mechanisms. Moreover, molecular evolution patterns suggest that, in addition to vertical transmission, 'Ca.Moeniiplasma' is able to transmit horizontally among distinct Glomeromycotina host lineages and exchange genes. On the basis of these unique lifestyle features, the new species 'Candidatus Moeniiplasma glomeromycotorum' is proposed.


Assuntos
Micorrizas , Filogenia , Simbiose , Tenericutes/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Evolução Molecular , Plantas/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tenericutes/genética , Tenericutes/isolamento & purificação
18.
Molecules ; 22(5)2017 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-28468293

RESUMO

Silk sericin has great potential as a biomaterial for biomedical applications due to its good hydrophilicity, reactivity, and biodegradability. To develop multifunctional sericin materials for potential antibacterial application, a one-step synthesis method for preparing silver nanoparticles (AgNPs) modified on polydopamine-coated sericin/polyvinyl alcohol (PVA) composite films was developed. Polydopamine (PDA) acted as both metal ion chelating and reducing agent to synthesize AgNPs in situ on the sericin/PVA composite film. Scanning electron microscopy and energy dispersive spectroscopy analysis revealed that polydopamine could effectively facilitate the high-density growth of AgNPs as a 3-D matrix. X-ray diffractometry studies suggested the synthesized AgNPs formed good face-centered cubic crystalline structures. Contact angle measurement and mechanical test indicated AgNPs modified PDA-sericin/PVA composite film had good hydrophilicity and mechanical property. The bacterial growth curve and inhibition zone assays showed the AgNPs modified PDA-sericin/PVA composite film had long-term antibacterial activities. This work develops a new method for the preparation of AgNPs modified PDA-sericin/PVA film with good hydrophilicity, mechanical performance and antibacterial activities for the potential antimicrobial application in biomedicine.


Assuntos
Antibacterianos/síntese química , Indóis/química , Nanopartículas Metálicas/química , Polímeros/química , Álcool de Polivinil/química , Sericinas/química , Prata/química , Adsorção , Antibacterianos/farmacologia , Bandagens , Materiais Revestidos Biocompatíveis/química , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Nanocompostos/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resistência à Tração , Molhabilidade
19.
Chaos ; 24(3): 033117, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25273197

RESUMO

The stability of a binary airfoil with feedback control under stochastic disturbances, a non-Gaussian colored noise, is studied in this paper. First, based on some approximated theories and methods the non-Gaussian colored noise is simplified to an Ornstein-Uhlenbeck process. Furthermore, via the stochastic averaging method and the logarithmic polar transformation, one dimensional diffusion process can be obtained. At last by applying the boundary conditions, the largest Lyapunov exponent which can determine the almost-sure stability of the system and the effective region of control parameters is calculated.

20.
Sheng Wu Gong Cheng Xue Bao ; 40(1): 211-225, 2024 Jan 25.
Artigo em Zh | MEDLINE | ID: mdl-38258642

RESUMO

The banana Fusarium wilt (BFW) caused by Fusarium oxysporum f. sp. cubense tropical race4 (FocTR4) is difficult to control worldwide, which causes a huge economic losse to banana industry. The purpose of this study was to screen Trichoderma strains with antagonistic activity against FocTR4, to isolate and purify the active compound from the fermentation broth, so as to provide important biocontrol strains and active compound resources. In this work, Trichoderma strains were isolated and screened from the rhizosphere soil of crops, and the strains capable of efficiently inhibiting FocTR4 were screened by plate confrontation, and further confirmed by testing inhibition for the conidial germination and mycelial growth of FocTR4. The phylogenetic tree clarified the taxonomic status of the biocontrol strains. Moreover, the active components in the fermentation broth of the strains were separated and purified by column chromatography, the structure of the most active component was analyzed by nuclear magnetic resonance spectroscopy (NMR), the BFW control effect was tested by pot experiments. We obtained a strain JSHA-CD-1003 with antagonistic activity against FocTR4, and the inhibition rate from plate confrontation was 60.6%. The fermentation broth of JSHA-CD-1003 completely inhibited the germination of FocTR4 conidia within 24 hours. The inhibition rate of FocTR4 hyphae growth was 52.6% within 7 d. A phylogenetic tree was constructed based on the ITS and tef1-α gene tandem sequences, and JSHA-CD-1003 was identified as Trichoderma brevicompactum. Purification and NMR identification showed that the single active compound was trichodermin, and the minimum inhibitory concentration (MIC) was 25 µg/mL. Pot experiments showed that the fermentation broth of strain JSHA-CD-1003 was effective against BFW. The control rate of leaf yellowing was 47.4%, and the rate of bulb browning was 52.0%. Therefore, JSHA-CD-1003 effectively inhibited FocTR4 conidial germination and mycelium growth through producing trichodermin, and showed biocontrol effect on banana wilt caused by FocTR4, thus is a potential biocontrol strain.


Assuntos
Fusarium , Hypocreales , Musa , Filogenia , Tricodermina
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