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1.
Inorg Chem ; 63(19): 8782-8790, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38691448

RESUMO

Potocatalytic hydrogen evolution represnets a promising way to achieve renewable energy sources. Dual heterojunctions with an inverse opal structure are proposed for addressing fundamental challenges (low surface area, inefficient light absorption, and poor charge separation) in photocatalytic water splitting. Inverse opal structure and Co3O4 were introduced to design and synthesize a ZnO/ZnS/Co3O4 (IO-ZnO/ZnS/Co3O4) photocatalyst. Morphology characterizations and photoelectric measurements reveal that the introduction of three-dimensional (3D) structures and dual heterojunctions improves light utilization efficiency and accelerates charge separation, greatly promoting photoelectric performance. The as-prepared IO-ZnO/ZnS/Co3O4 manifests superior photocurrent density (0.49 mA/cm2), which is 4 times higher than that of IO-ZnO/ZnS due to the existence of dual heterojunctions. The result is further confirmed by an enhanced H2 production rate (153.01 µmol/g/h) in pure water. Notably, excellent cycling stability is achieved in pure water because Co3O4 can rapidly capture photogenerated holes to inhibit severe photocorrosion of ZnO/ZnS. Therefore, this work presents a new insight into inhibiting photocorrosion of metal sulfides and promoting their photoelectric performance by combining 3D structures and dual heterojunctions.

2.
Eur J Pharmacol ; 968: 176423, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38365109

RESUMO

Calcific aortic valve disease (CAVD) is a progressive cardiovascular disorder involving multiple pathogenesis. Effective pharmacological therapies are currently unavailable. Sirtuin6 (SIRT6) has been shown to protect against aortic valve calcification in CAVD. The exact regulatory mechanism of SIRT6 in osteoblastic differentiation remains to be determined, although it inhibits osteogenic differentiation of aortic valve interstitial cells. We demonstrated that SIRT6 was markedly downregulated in calcific human aortic valves. Mechanistically, SIRT6 suppressed osteogenic differentiation in human aortic valve interstitial cells (HAVICs), as confirmed by loss- and gain-of-function experiments. SIRT6 directly interacted with Runx2, decreased Runx2 acetylation levels, and facilitated Runx2 nuclear export to inhibit the osteoblastic phenotype transition of HAVICs. In addition, the AKT signaling pathway acted upstream of SIRT6. Together, these findings elucidate that SIRT6-mediated Runx2 downregulation inhibits aortic valve calcification and provide novel insights into therapeutic strategies for CAVD.


Assuntos
Estenose da Valva Aórtica , Valva Aórtica/patologia , Calcinose , Sirtuínas , Humanos , Valva Aórtica/metabolismo , Regulação para Baixo , Osteogênese/genética , Células Cultivadas , Estenose da Valva Aórtica/genética , Estenose da Valva Aórtica/metabolismo , Estenose da Valva Aórtica/patologia , Sirtuínas/genética , Sirtuínas/metabolismo
3.
Cancer Lett ; 584: 216619, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38211651

RESUMO

The cystine/glutamate antiporter SLC7A11, as the key regulator of ferroptosis, functions to transport cystine for glutathione biosynthesis and antioxidant defense. Accumulating evidence has shown that SLC7A11 is overexpressed in multiple human cancers and promotes tumor growth and progression. However, the exact mechanism underlying this key protein remains unclear. In this study, we confirmed that SLC7A11 is S-palmitoylated in glioblastoma, and this modification is required for SLC7A11 protein stability. Moreover, we revealed that ZDHHC8, a member of the protein palmitoyl transferases (PATs), catalyzes S-palmitoylation of SLC7A11 at Cys327, thereby decreasing the ubiquitination level of SLC7A11. Furthermore, AMPKα1 directly phosphorylates ZDHHC8 at S299, strengthening the interaction between ZDHHC8 and SLC7A11, leading to SLC7A11 S-palmitoylation and deubiquitination. Functional investigations showed that ZDHHC8 knockdown impairs glioblastoma (GBM) cell survival via promoting intracellular ferroptosis events, which could be largely rescued by ectopic expression of SLC7A11. Clinically, ZDHHC8 expression positively correlates with SLC7A11 and AMPKα1 expression in clinical glioma specimens. This study underscores that ZDHHC8-mediated SLC7A11 S-palmitoylation is critical for ferroptosis resistance during GBM tumorigenesis, indicating a novel treatment strategy for GBM.


Assuntos
Ferroptose , Glioblastoma , Humanos , Sistema y+ de Transporte de Aminoácidos/genética , Sistema y+ de Transporte de Aminoácidos/metabolismo , Linhagem Celular Tumoral , Cistina/metabolismo , Glioblastoma/metabolismo , Lipoilação , Fosforilação
4.
J Clin Med ; 12(8)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37109163

RESUMO

BACKGROUND: A patent false lumen (FL) in patients with thoracic endovascular aortic repair (TEVAR)-treated type B aortic dissection (TBAD) can cause a significant risk for late aortic expansion (LAE). We hypothesize that preoperative features can predict the occurrence of LAE. METHODS: Sufficient preoperative and postoperative follow-up clinical and imaging feature data for patients treated with TEVAR in the First Affiliated Hospital of Nanjing Medical University from January 2018 to December 2020 were collected. A univariate analysis and multivariable logistic regression analysis were used to find potential risk factors of LAE. RESULTS: Ninety-six patients were finally included in this study. The mean age was 54.5 ± 11.7 years and 85 (88.5%) were male. LAE occurred in 15 (15.6%) of 96 patients after TEVAR. Two preoperative factors showed strong associations with LAE according to the multivariable logistic regression analysis: preoperative partial thrombosis of the FL (OR = 10.989 [2.295-48.403]; p = 0.002) and the maximum descending aortic diameter (OR = 1.385 [1.100-1.743] per mm increase; p = 0.006). CONCLUSIONS: Preoperative partial thrombosis of the FL and an increase in the maximum aortic diameter are strongly associated with late aortic expansion. Additional interventions of the FL may help to improve the prognosis of patients with the high risk of late aortic expansion.

5.
Bioorg Chem ; 133: 106409, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36753963

RESUMO

Histone demethylation is a key post-translational modification of chromatin, and its dysregulation affects a wide array of nuclear activities including the maintenance of genome integrity, transcriptional regulation, and epigenetic inheritance. Lysine specific demethylase 6A (KDM6A, also known as UTX) is an Fe2+- and α-ketoglutarate- dependent oxidase which belongs to KDM6 Jumonji histone demethylase subfamily, and it can remove mono-, di- and tri-methyl groups from methylated lysine 27 of histone H3 (H3K27me1/2/3). Mounting studies indicate that KDM6A is responsible for driving multiple human diseases, particularly cancers and pharmacological inhibition of KDM6A is an effective strategy to treat varieties of KDM6A-amplified cancers in cellulo and in vivo. Although there are several reviews on the roles of KDM6 subfamily in cancer development and therapy, all of them only simply introduce the roles of KDM6A in cancer without systematically summarizing the specific mechanisms of KDM6A in tumorigenesis, which greatly limits the advances on the understanding of roles KDM6A in varieties of cancers, discovering targeting selective KDM6A inhibitors, and exploring the adaptive profiles of KDM6A antagonists. Herein, we present the structure and functions of KDM6A, simply outline the functions of KDM6A in homeostasis and non-cancer diseases, summarize the role of KDM6A and its distinct target genes/ligand proteins in development of varieties of cancers, systematically classify KDM6A inhibitors, sum up the difficulties encountered in the research of KDM6A and the discovery of related drugs, and provide the corresponding solutions, which will contribute to understanding the roles of KDM6A in carcinogenesis and advancing the progression of KDM6A as a drug target in cancer therapy.


Assuntos
Histona Desmetilases , Neoplasias , Humanos , Carcinogênese/metabolismo , Histona Desmetilases/metabolismo , Histonas/química , Histonas/metabolismo , Lisina/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/genética
7.
Environ Technol ; 44(1): 82-92, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34346854

RESUMO

To construct a simultaneous nitrification and denitrification-microbial fuel cell (SND-MFC) reactor for stable electricity generation, a heterotrophic nitrification-aerobic denitrification strain was isolated and purified from aerobic activated sludge from a sewage treatment plant. The strain with an optimal nitrogen removal performance, which was identified as Pseudomonas, was inoculated into the SND-MFC as a single strain. Different electrode materials and electrode distances (EDs) were investigated. The results showed that a maximum ammonium removal rate of 92.31% and a maximum power density of 134.28 mW/m3 were obtained by the SND-MFC using graphene film as the electrodes material. Decreasing the ED did not significantly improved the power generation performance of the pure strain SND-MFC at the initial stage. When the electrode distance of the SND-MFC was 4 cm, the best generation efficiency was achieved with a maximum power density of 151.84 mW/m3.


Assuntos
Fontes de Energia Bioelétrica , Nitrificação , Desnitrificação , Eletricidade , Esgotos , Processos Heterotróficos , Nitrogênio
8.
Environ Sci Pollut Res Int ; 30(12): 33598-33608, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36484942

RESUMO

Land use is an effective way to reduce carbon emission in the recycling process of municipal sludge compost; meanwhile, heavy metals (HMs) in the sludge can be phytoextracted by ornamental plants. As an eco-friendly soil amendment, citric acid (CA) has been reported to be of great potential aid to phytoremediation, and its effect on ryegrass (Lolium perenne L.) extraction of HMs (Zn, Ni, Pb, Cu, and Cd) from municipal sewage sludge compost-amended (MSSC) soils has been investigated through pot experiments in the study. The growth of ryegrass was significantly promoted under 2 and 4 mmol kg-1 CA treatments. The concentrations of HMs in MSSC soil after 45-day planting were significantly reduced ([Formula: see text]), and they were further reduced except for Cu while CA treated. The acid-extractable fraction of HMs in the soil was increased significantly as CA treated, and further improvement could be found when CA dose increased, which was due to the decreased soil pH and the complexation of CA with metal ions. The phytoremediation factor (PRF) was proposed to assess the phytoremediation efficiency, which was obtained as a ratio of the product of the biomass and metal concentration of plant shoot between the CA-treated group and the control group. When the CA dose was 6 mmol kg-1, the average PRF of five heavy metals reached 2.29, and Cd was the highest (3.72), demonstrating that CA had great promotion on phytoremediation of heavy metals. This study made a contribution to the research of phytoremediation in sludge land use by demonstrating ryegrass as an ideal bioaccumulator for heavy metals, especially for Cd.


Assuntos
Compostagem , Lolium , Metais Pesados , Poluentes do Solo , Esgotos , Solo , Cádmio , Ácido Cítrico , Poluentes do Solo/análise , Metais Pesados/análise
9.
Appl Opt ; 61(13): 3819-3826, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36256425

RESUMO

With the development of laser metrology, the dual-comb system has natural superiority in the measuring fields. Specifically, distance and velocity represent a basic state for the target in space. We propose an application mode of the dual-comb interferometry integrated into the field programmable gate array. A high-speed parallel processor truly gives full play to the benefit of the data processing rate. The algorithm of the peak extraction and the address matching also bring an efficient working mode into the whole scheme. To verify the performance of this system, we devise a series of experiments for distance and velocity, respectively. The data processing rate of the distance is 425 Hz and that of the corresponding average velocity is 0.425 Hz, which is flexible for different measuring conditions. The experimental results show that the difference can be well within 252.8 µm at 5 m range and 284.9 µm/s over 0.5 m/s.

10.
Front Plant Sci ; 13: 968719, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36247600

RESUMO

Karst ecosystems represent a typical heterogeneous habitat, and it is ubiquitous with varying interactive patches of rock and soil associated with differential weathering patterns of carbonate rocks. Arbuscular mycorrhizae fungi (AMF) play an important role in regulating plant growth and nutrition in heterogeneous karst habitats. However, it remains unclear how AMF affects the growth and nutrition of plants in heterogeneous karst soil with varying patches and weathering gravel. A heterogeneous experiment with Bidens pilosa L. was conducted in a grid microcosm through patching karst soil with different gravel contents. The experimental treatments included the AMF treatments inoculated with (M+) or without (M-) fungus Glomus etunicatum; the substrate patchiness treatments involved different sizes of the homogeneous patch (Homo), the heterogeneous large patch (Hetl), and the heterogeneous small patch (Hets); the substrate gravel treatments in the inner patch involved the free gravel (FG), the low gravel (LG) 20% in 80% soil, and the high gravel (HG) 40% in 60% soil. Plant traits related to growth and nutrients were analyzed by comparing substrate gravel content and patch size. The results showed that AMF was more beneficial in increasing the aboveground biomass of B. pilosa under the LG and HG substrates with a higher root mycorrhizal colonization rate than under the FG substrate with a lower root mycorrhizal colonization rate. AMF enhanced higher growth and nutrients for B. pilosa under the LG and HG substrates than under the FG substrate and under the Hets than under the Hetl. Moreover, AMF alleviated the limited supply of N for B. pilosa under all heterogeneous treatments. Furthermore, the response ratio LnRR of B. pilosa presented that the substrate gravel promoted the highest growth, N and P absorption than the substrate patchiness with M+ treatment, and the gravel content had a more effect on plant growth and nutrition as compared to the patch size. Overall, this study suggests that plant growth and nutrition regulated by AMF mainly depend on the substrate gravel content rather than the spatial patchiness in the heterogeneous karst habitat.

11.
J Kidney Cancer VHL ; 9(2): 32-38, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36118793

RESUMO

Cardiac metastases from renal cell carcinoma (RCC) are very rare. We describe the case of a woman with RCC with cardiac metastases involving the entire right atrium, penetrating through the myocardium, with extension into the tricuspid valve and right ventricle. This report highlights the unique challenge of the diagnosis and treatment of cardiac metastases in RCC.

12.
Front Oncol ; 12: 993775, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36119505

RESUMO

Breast cancer (BC) is a common malignancy that mainly occurred in women and it has become the most diagnosed cancer annually since 2020. Berberine (BBR), an alkaloid extracted from the Berberidacea family, has been found with broad pharmacological bioactivities including anti-inflammatory, anti-diabetic, anti-hypertensive, anti-obesity, antidepressant, and anticancer effects. Mounting evidence shows that BBR is a safe and effective agent with good anticancer activity against BC. However, its detailed underlying mechanism in BC treatment remains unclear. Here, we will provide the evidence for BBR in BC therapy and summarize its potential mechanisms. This review briefly introduces the source, metabolism, and biological function of BBR and emphasizes the therapeutic effects of BBR against BC via directly interacting with effector proteins, transcriptional regulatory elements, miRNA, and several BBR-mediated signaling pathways. Moreover, the novel BBR-based therapeutic strategies against BC improve biocompatibility and water solubility, and the efficacies of BBR are also briefly discussed. Finally, the status of BBR in BC treatment and future research directions is also prospected.

13.
Transl Oncol ; 26: 101510, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36122506

RESUMO

Several different signaling pathways and molecular mechanisms have been identified as responsible for controlling critical functions in human cancer cells, such as selective growth and proliferative advantage, altered stress response favoring overall survival, vascularization, invasion and metastasis, metabolic rewiring, an abetting microenvironment, and immune modulation. This concise summary will provide a selective review of recent studies of key signal transduction pathways, including mitogen-activated protein kinase (MAPK) pathway, Phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling, and Wnt/ß-catenin signaling pathway, which are altered in cancer cells, as the novel and promising therapeutic targets.

14.
Microsc Res Tech ; 85(11): 3589-3599, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35869784

RESUMO

The pollution of lead (Pb (II)) to water resources is becoming more and more serious. It is always a difficult problem to find efficient and low-cost adsorbents. Chicken manure (CM) and Chinese medicine residue (CMR) were modified with potassium dihydrogen phosphate (KH2 PO4 ) and pyrolyzed to obtain a modified material (PBC) for the treatment of Pb(II) in an aqueous solution. A variety of characterization analysis results could prove that KH2 PO4 was successfully introduced to PBC. By adjusting the initial pH, the zeta potential of PBC varies from -3.2 to -43.1 mV, it could be seen that PBC had excellent applicability in the broad range pH value (1.0-6.0). Experimental and model results showed that R2 of the pseudo-first order kinetic model and the pseudo-second order kinetic model are greater than 0.99, indicating that that physical and chemical adsorption played a significant role in Pb(II) removal by PBC. An adsorption isotherm analysis showed that the adsorption capacity n in this study is greater than 1, confirming that PBC has a good adsorption effect on Pb (II). R2 of the Langmuir model of PBC is 0.981, and its maximum adsorption capacity of Pb(II) could reach 599.4 mg/g. Environmentally friendly PBC could be used as an effective adsorbent to remove Pb(II) from aqueous systems. RESEARCH HIGHLIGHTS: Chicken manure and Chinese medicine residue were converted into biochar to improve utilization. The modified biochar exhibited extraordinary Pb(II) adsorption capacity. Adsorption mechanisms: Surface complexation, ions exchange, coprecipitation, and so on. Remained great Pb(II) removal efficiency at different pH and Pb(II) concentration.


Assuntos
Pirólise , Poluentes Químicos da Água , Adsorção , Animais , Carvão Vegetal , Galinhas , Concentração de Íons de Hidrogênio , Íons , Cinética , Chumbo , Esterco/análise , Medicina Tradicional Chinesa , Fósforo , Água/química , Poluentes Químicos da Água/análise
15.
Artigo em Inglês | MEDLINE | ID: mdl-35742611

RESUMO

The environmental pollution caused by logistics packaging in China has attracted increasing attention in recent years, and circular packaging is considered an effective means to solve the aforementioned problem. Therefore, this study considers the uncertainty of the external environment; constructs a stochastic game model of circular logistics-packaging promotion, which consists of environmental regulators, logistics enterprises, and consumers; collects data related to logistics packaging in China to describe the current circular-packaging promotion dilemma; and conducts a parameter-sensitivity analysis. The results show that (1) after a short period of fluctuation, the environmental regulator will lock in the "strong regulation" strategy, whereas logistics enterprises and consumers will quickly lock in the "no promotion" and "negative use" strategies. (2) The change in the initial probability will affect the rate of strategy evolution of the gaming system. (3) The "strong regulatory" strategy of environmental regulators and the increase in the number of circular-packaging cycles can help establish a logistics-recycling-packaging system. (4) The increase in recycling incentives can cause consumers to shift toward "active use" strategies, but this has accelerated the rate at which logistics companies lock into "no promotion" strategies. (5) The increase in the intensity of random interference will raise the fluctuation of the evolution of the game subject. For logistics enterprises, moderate random interference helps them evolve toward the "promotion" strategy.


Assuntos
Gerenciamento de Resíduos , China , Embalagem de Produtos , Reciclagem , Gerenciamento de Resíduos/métodos
16.
Org Lett ; 24(22): 3987-3992, 2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35639094

RESUMO

A nickel-catalyzed reductive cross-coupling reaction of aryl cyclopropyl ketones with easily accessible unactivated alkyl bromides to access aryl alkyl ketones has been developed. This strategy facilitates access to various of γ-alkyl-substituted ketones via ring opening of cyclopropyl ketones (26 examples, 50-90% yield). Initial mechanistic studies revealed that the reaction proceeds via radical cleavage of the alkyl bromide.

17.
AMB Express ; 12(1): 57, 2022 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-35567691

RESUMO

Acetone-butanol-ethanol (ABE) fermentation is a traditional way for solvents production through bioconversion by Clostridium species. It is still a challenge to obtain metabolic engineering strains with high ABE yield. Screening strains with remarkable characteristics from nature and improving ABE yield by mutation are viable approaches. Clostridium beijerinckii XH 0906, a newly isolated strain, produces butanol and isopropanol (BI) as the main end-products (9.1 g/L BI) during fermentation with glucose as the sole carbon source. The screening process for this strain was performed under aerobic conditions rather than anaerobic environment. Thus, it is a robust stain capable of oxygen-tolerant BI fermentation. Furthermore, C. beijerinckii XH 0906 fermented xylose and glucose simultaneously to produce BI. A mutant strain obtained by ultraviolet (UV) mutagenesis, C. beijerinckii XH 29, had improved BI production capacity and could produce 17.0 g/L BI and 18.4 g/L BI using glucose or corn stover hydrolysate, respectively as the carbon source. Interestingly, C. beijerinckii XH 29 also produced up to 19.3 g/L isopropanol through fermentation of a glucose-acetone mix. These results indicate that C. beijerinckii XH 29 is an excellent BI producer with great potential for industrial applications.

18.
Environ Sci Pollut Res Int ; 29(3): 3853-3863, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34402012

RESUMO

Biochar (BC) obtained by the co-pyrolysis of municipal sewage sludge (MSS) and sunflower seed shells (SSS) was utilized to support nanoscale zero-valent iron particles (nZVI) for the synthesis of a composite material (nZVI-BC) for Cr(VI) removal from aqueous systems. A series of characterization methods confirmed successful immobilization of nZVI on the surface of biochar with no aggregation. Batch experiments showed that the initial pH, initial Cr(VI) concentration, and nZVI-BC dose all significantly affected the Cr(VI) removal using nZVI-BC. The kinetics for Cr(VI) removal via nZVI-BC could be better explained by the pseudo-second-order (PSO) adsorption model. Adsorption isotherms analysis demonstrated the superior Cr(VI) removal capability of nZVI-BC in comparison to bare nZVI and BC. nZVI-BC can be reused after the regeneration process by applying 0.1 M H2SO4 and 0.1 M NaBH4 solutions. The reaction mechanism for Cr(VI) removal might involve its chemical reduction on the nZVI-BC surface. Overall, environmentally friendly nZVI-BC was highly efficient in Cr(VI) removal from aqueous systems.


Assuntos
Ferro , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cromo , Esgotos , Poluentes Químicos da Água/análise
19.
Front Plant Sci ; 12: 769989, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34868168

RESUMO

The rind appearance of melon is one of the most vital commercial quality traits which determines the preferences and behavior of consumers toward the consumption of melon. In this study, we constructed an F2 population derived from SC (mottled rind) and MG (non-mottled rind) lines for mapping the mottled rind gene(s) in melon. Genetic analysis showed that there were two dominant genes (CmMt1 and CmMt2) with evidence of epistasis controlling the mottled rind. Meanwhile, the phenotypic segregation ratio implied that the immature rind color had an epistatic effect on the mottled rind, which was regulated by CmAPRR2. A Kompetitive Allele-Specific PCR (KASP) DNA marker (CmAPRR2 SNP(G/T) ) was developed and shown to co-segregate with rind color, confirming that CmAPRR2 was CmMt1. Using bulked segregant analysis sequencing and KASP assays, CmMt2 was fine-mapped to an interval of 40.6 kb with six predicted genes. Functional annotation, expression analysis, and sequence variation analyses confirmed that AtCPSFL1 homolog, MELO3C026282, was the most likely candidate gene for CmMt2. Moreover, pigment content measurement and transmission electron microscopy analysis demonstrated that CmMt2 might participate in the development of chloroplast, which, in turn, decreases the accumulation of chlorophyll. These results provide insight into the molecular mechanism underlying rind appearance and reveal valuable information for marker-assisted selection breeding in melon.

20.
Viruses ; 13(10)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34696380

RESUMO

Most endolysins of dsDNA phages are exported by a holin-dependent mechanism, while in some cases endolysins are exported via a holin-independent mechanism. However, it is still unclear whether the same endolysins can be exported by both holin-dependent and holin-independent mechanisms. This study investigated the lysis system of OP2-like phage X2 infecting Xanthomonas oryzae pv. oryzae, causing devastating bacterial leaf blight disease in rice. Based on bioinformatics and protein biochemistry methods, we show that phage X2 employs the classic "holin-endolysin" lysis system. The endolysin acts on the cell envelope and exhibits antibacterial effects in vitro, while the holin facilitates the release of the protein into the periplasm. We also characterized the role of the transmembrane domain (TMD) in the translocation of the endolysin across the inner membrane. We found that the TMD facilitated the translocation of the endolysin via the Sec secretion system. The holin increases the efficiency of protein release, leading to faster and more efficient lysis. Interestingly, in E. coli, the expression of either holin or endolysin with TMDs resulted in the formation of long rod shaped cells. We conclude that the TMD of X2-Lys plays a dual role: One is the transmembrane transport while the other is the inhibition of cell division, resulting in larger cells and thus in a higher number of released viruses per cell.


Assuntos
Bacteriófagos/enzimologia , Bacteriófagos/genética , Endopeptidases/genética , Proteínas Virais/genética , Xanthomonas/virologia , Bacteriólise , Bacteriófagos/classificação , Endopeptidases/metabolismo , Escherichia coli/genética , Filogenia
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