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1.
Oncologist ; 28(8): e591-e599, 2023 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-36929946

RESUMO

BACKGROUND: For patients with cN0 and T1-2 breast cancer, sentinel lymph node biopsy (SLNB) can provide survival results equivalent to axillary lymph node dissection (ALND). However, whether it can be performed on T3-4c patients is still controversial. MATERIALS AND METHODS: Female patients diagnosed with cN0, T3-4c, and M0 breast cancer from 2004 to 2019 were identified using the surveillance, epidemiology and end results (SEER) database and divided into 2 groups, the SLNB group (1-5 regional lymph nodes examined) and the ALND group (≥10 regional lymph nodes examined). Finally, only those with pN0 disease were included in the SLNB group. The baseline differences in clinicopathological characteristics between groups were eliminated by propensity score matching (PSM). We also conducted subgroup analyses according to age, overall TNM stage, breast cancer subtypes, surgical approaches, radiation therapy, and chemotherapy. The primary endpoint was survival. RESULTS: With a mean follow-up of 75 months, a total of 186 deaths were reported among 864 patients. The overall survival (OS) and breast cancer-specific survival (BCSS) in the SLNB group were 78.2% and 87.5%, respectively, and that in the ALND group were 78.7% and 87.3%, respectively. The unadjusted hazard ratio (HR) for OS and BCSS in the SLNB group (vs. the ALND group) was 0.922 (95% CI, 0.691-1.230, P = .580) and 0.874 (95% CI, 0.600-1.273, P = .481), respectively. Besides, the OS and BCSS between the 2 groups were also similar in all subgroup analyses. CONCLUSIONS: SLNB may be performed on female patients with cN0, T3-4c, and M0 breast cancer.


Assuntos
Neoplasias da Mama , Linfonodo Sentinela , Humanos , Feminino , Biópsia de Linfonodo Sentinela/métodos , Neoplasias da Mama/patologia , Metástase Linfática/patologia , Estadiamento de Neoplasias , Excisão de Linfonodo/métodos , Linfonodos/patologia , Axila/patologia , Linfonodo Sentinela/cirurgia , Linfonodo Sentinela/patologia
2.
Biochem Biophys Res Commun ; 610: 99-106, 2022 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-35461073

RESUMO

Abnormal expression of mucin-type O-glycosylation has been reported to be associated with a variety of human cancers including gliomas. However, little is known about its contribution to the malignancy of Glioblastoma Multiforme (GBM), the deadliest form of brain tumors. Here, we conducted a detailed analysis of the expression profiles of GALNT gene family, which encode polypeptide-N-acetyl-galactosaminyltransferases (GalNAc-Ts) and are responsible for initiating O-glycans, both in the Cancer Genome Atlas (TCGA) and in the Chinese Glioma Genome Atlas (CGGA) databases. We discovered that GALNT12 is the only member within the GALNT family, whose expression demonstrated significant correlation with a worse prognosis of GBM. Genetic knockdown (KD) and knockout (KO) of GALNT12 in U87 MG, a representative GBM cell line with high GALNT12 expression, confirmed that GALNT12 deficiency leads to decreased cell proliferation, migration and invasion. Mechanism study revealed that GALNT12 KD and KO decreased the level of epidermal growth factor (EGF) and consequently attenuated Akt signaling within the cell. In summary, our results indicated that GALNT12 facilitates the malignant characteristics of GBM by influencing the PI3K/Akt/mTOR axis and may serve as a novel prognosis biomarker and a potential therapeutic target of GBM.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Glioma , N-Acetilgalactosaminiltransferases , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Glioblastoma/patologia , Glioma/patologia , Humanos , N-Acetilgalactosaminiltransferases/genética , N-Acetilgalactosaminiltransferases/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo
3.
Biochem Biophys Res Commun ; 517(4): 735-740, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31420167

RESUMO

Survival of a species depends on reproductive fitness and a plant's floral transition is controlled by developmental and environmental signals. In Arabidopsis, the floral integrators SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1) and FT (FLOWERING LOCUS T) sense various pathway signals to activate floral meristem identity genes. At high stress intensity, greater nuclear accumulation of the zinc-finger transcription factor OXS2 (OXIDATIVE STRESS 2) activates an early-flowering stress-escape response. Curiously, accumulation of OXS2 in the cytoplasm can delay flowering, prompting the hypothesis that in absence of stress, OXS2 helps to maintain vegetative growth. While the mechanism of stress-escape was identified as the OXS2-mediated transcription of SOC1, how cytoplasmic OXS2 delays flowering was unknown. Here, we report that OXS2 can interact indirectly with florigen FT and transcription factor FD (FLOWERING LOCUS D), the two proteins known to induce floral transition. By using 14-3-3Ω as a bridge linker, OXS2 can alter the subcellular distribution of FT. This lead to a speculation on how cytoplasmic OXS2 is able to prevent early flowering, by keeping FT from the nucleus.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fatores de Transcrição/metabolismo , Proteínas 14-3-3/metabolismo , Ligação Proteica
4.
Biochem Biophys Res Commun ; 519(3): 585-590, 2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31540691

RESUMO

Stress-induced regulation of flowering time insures evolutionary fitness. Stress-induced late flowering is thought to result from a plant evoking tolerance mechanism to wait out the stress before initiating reproduction. Stress-induced early flowering, on the other hand, is thought to be a stress-escape response. By shortening their life cycle to produce seeds before severe stress leads to death, this insures survival of the species at the cost of lower seed yield. Previously, we reported that overexpression of OXS3 (OXIDATIVE STRESS 3) could enhance tolerance to cadmium and oxidizing agents in Arabidopsis whereas an oxs3 null mutant was slightly more sensitive to these chemicals. In this study, we found that the absence of OXS3 also causes early flowering under a mild drought stress treatment. This contrasts with the behavior of wild type Ws4 and Col ecotypes that responded to the same condition by delaying flowering time. We tested the hypothesis that OXS3 might ordinarily exert a negative regulatory role on flowering during drought stress, which in its absence, would lead to stress-induced early flowering. In a search of whether OXS3 could interfere with regulators that activate flowering, we found that OXS3 could bind SOC1 in vitro and in vivo. Overexpression of OXS3 in a transient expression assay was found to repress the AP1 promoter, and the full repression effect required SOC1. It is possible that the OXS3/SOC1 interaction serves to prevent precocious flower development and prevent low seed set from a premature stress-induced flowering response.


Assuntos
Proteínas de Arabidopsis/metabolismo , Desastres , Secas , Flores/crescimento & desenvolvimento , Proteínas de Domínio MADS/metabolismo , Proteínas de Arabidopsis/genética , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Domínio MADS/genética
5.
ACS Appl Mater Interfaces ; 16(13): 15741-15751, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38518114

RESUMO

The ex vivo replication of the highly helical and fibril structures of load-bearing soft tissue is a challenging goal for the study of hydrogels. Inspired by nature, we prepared tissue-like physical gels based on curdlan and gelatin by self-assembly. The hybrid gels have a flexible fibril-matrix architecture, and the fibril orientation is highly tunable. The tensile strength of the gels can be tuned from ∼1.1 to ∼16.5 MPa. The coil-helix transition and nanofibril formation process in the self-assembly system was thoroughly investigated. These helical gels exhibit excellent cell compatibility, which supports adhesion and oriented growth of neural cells. Furthermore, the oriented nanofibrils in the gel are found to be associated with an upregulated expression of regeneration-related genes like N-cadherin (Cdh2) and neural growth factor (NGF). Owing to the strength and biomimetic structure, these gels have great potential in tissue engineering applications.


Assuntos
Gelatina , beta-Glucanas , Gelatina/química , Hidrogéis/farmacologia , Hidrogéis/química , Engenharia Tecidual
6.
J Adv Res ; 2024 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-39103048

RESUMO

INTRODUCTION: Mitophagy, a selective form of autophagy responsible for maintaining mitochondrial homeostasis, regulates the antiviral immune response and acts as viral replication platforms to facilitate infection with various viruses. However, its precise role in herpes simplex virus 1 (HSV-1) infection and herpes simplex encephalitis (HSE) remains largely unknown. OBJECTIVES: We aimed to investigate the regulation of mitophagy by HSV-1 neurotropic infection and its role in viral encephalitis, and to identify small compounds that regulate mitophagy to affect HSV-1 infection. METHODS: The antiviral effects of compounds were investigated by Western blot, RT-PCR and plaque assay. The changes of Parkin (PRKN)-mediated mitophagy and Nuclear Factor kappa B (NFKB)-mediated neuroinflammation were examined by TEM, RT-qPCR, Western blot and ELISA. The therapeutic effect of taurine or PRKN-overexpression was confirmed in the HSE mouse model by evaluating survival rate, eye damage, neurodegenerative symptoms, immunohistochemistry analysis and histopathology. RESULTS: HSV-1 infection caused the accumulation of damaged mitochondria in neuronal cells and in the brain tissue of HSE mice. Early HSV-1 infection led to mitophagy activation, followed by inhibition in the later viral infection. The HSV-1 proteins ICP34.5 or US11 deregulated the EIF2S1-ATF4 axis to suppress PRKN/Parkin mRNA expression, thereby impeding PRKN-dependent mitophagy. Consequently, inhibition of mitophagy by specific inhibitor midiv-1 promoted HSV-1 infection, whereas mitophagy activation by PRKN overexpression or agonists (CCCP and rotenone) attenuated HSV-1 infection and reduced the NF-κB-mediated neuroinflammation. Moreover, PRKN-overexpressing mice showed enhanced resistance to HSV-1 infection and ameliorated HSE pathogenesis. Furthermore, taurine, a differentially regulated gut microbial metabolite upon HSV-1 infection, acted as a mitophagy activator that transcriptionally promotes PRKN expression to stimulate mitophagy and to limit HSV-1 infection both in vitro and in vivo. CONCLUSION: These results reveal the protective function of mitophagy in HSE pathogenesis and highlight mitophagy activation as a potential antiviral therapeutic strategy for HSV-1-related diseases.

7.
Crit Rev Oncol Hematol ; 185: 103962, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36921780

RESUMO

BACKGROUND: HER2-low (human epidermal growth factor receptor 2) breast cancer takes up 40-50% in all breast cancer subtypes. The survival difference between HER2-low and HER2-zero breast cancers remain uncertain. Therefore, the aim of this study was to compare survival outcome of the two subtypes and to explore the impact of hormone receptor status. METHODS: A comprehensive medical literature search was performed by searching PubMed, EMBASE, and the Cochrane Libraries up to August 2022. We included observational studies reporting hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). The results of individual studies were pooled by random-effects models using Stata 16.0. Seventeen articles with a total of 78984 breast cancer patients were included in the meta-analysis. RESULTS: We observed a statistically significant association between low HER2 expression and better breast cancer survival outcomes (OS: HR: 0.83; 95% confidence interval: 0.75, 0.90; DFS/RFS: HR: 0.83; 95% confidence interval: 0.75, 0.91). In a subgroup analysis, we found that HER2-low patients had better survival outcomes relative to hormone receptor-positive breast cancer patients (OS: HR: 0.87; 95% confidence interval: 0.81, 0.93; DFS/RFS: HR: 0.91; 95% confidence interval: 0.85, 0.96). Similarly, in triple-negative breast cancer patients, we also observed a positive association between HER2 low expression and better survival (OS: HR: 0.85; 95% confidence interval: 0.71, 0.98; DFS/RFS: HR: 0.85; 95% confidence interval: 0.74, 0.95). CONCLUSIONS: Our study showed that HER2-low breast cancer had better survival outcomes compared to HER2 negative breast cancer in patients with early stage breast cancer, regardless of hormone receptor status. REGISTRATION: This meta-analysis was registered with PROSPERO (CRD42022335704) on June 10, 2022. AVAILABILITY OF DATA AND MATERIALS: All data generated or analysed during this study are included in this published article [and its supplementary information files].


Assuntos
Neoplasias da Mama , Receptor ErbB-2 , Neoplasias de Mama Triplo Negativas , Feminino , Humanos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Prognóstico , Modelos de Riscos Proporcionais , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/mortalidade
8.
Plant Sci ; 330: 111641, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36806610

RESUMO

Chlorophylls are the major pigments that harvest light energy during photosynthesis in plants. Although reactions in chlorophyll biogenesis have been largely known, little attention has been paid to the post-translational regulation mechanism of this process. In this study, we found that four lysine sites (K128/340/350/390) of NADPH:protochlorophyllide oxidoreductase A (PORA), which catalyzes the only light-triggered step in chlorophyll biosynthesis, were acetylated after dark-grown seedlings transferred to light via acetylomics analysis. Etiolated seedlings with K390 mutation of PORA had a lower greening rate and decreased PORA acetylation after illumination. Importantly, K390 of PORA was found extremely conserved in plants and cyanobacteria via bioinformatics analysis. We further demonstrated that the acetylation level of PORA was increased by exposing the dark-grown seedlings to the histone deacetylase (HDAC) inhibitor TSA. Thus, the HDACs probably regulate the acetylation of PORA, thereby controlling this non-histone substrate to catalyze the reduction of Pchlide to produce chlorophyllide, which provides a novel regulatory mechanism by which the plant actively tunes chlorophyll biosynthesis during the conversion from skotomorphogenesis to photomorphogenesis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Arabidopsis/genética , Arabidopsis/metabolismo , Oxirredutases/genética , NADP , Proteínas de Arabidopsis/metabolismo , Acetilação , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Luz , Clorofila , Protoclorifilida
9.
Biotechnol Lett ; 34(4): 747-54, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22130741

RESUMO

Agrobacterium tumefaciens-mediated transformation of tobacco leaves (Nicotiana tabacum) is used to study gene expression in a heterologous genetic background. Here, the Cre-loxP recombination system was used to detect T-DNA transfer by two A. tumefaciens cells harboring different binary vectors. Cre, under the control of the CaMV 35S promoter, was cloned into one vector, and a loxP cassette into another vector. A mixture of A. tumefaciens, in which each cell contained either a Cre- or loxP-vector, was co-infiltrated into tobacco leaves. After two days, excision of loxP-flanked DNA was detected by PCR and used as an estimate for co-transformation events. Strongest excision (> 50%) was observed when the loxP cassette was cloned into vector pPZP112 and Cre into pISV2678. This fast and easy technique can be used to assess the co-transformation efficiency of tobacco cells in future studies.


Assuntos
Agrobacterium tumefaciens/genética , Nicotiana/genética , Nicotiana/microbiologia , Recombinação Genética , Transformação Genética , Caulimovirus , DNA Bacteriano/genética , Engenharia Genética/métodos , Vetores Genéticos , Biologia Molecular/métodos , Folhas de Planta/genética , Folhas de Planta/microbiologia , Plasmídeos , Reação em Cadeia da Polimerase
10.
Int J Biol Macromol ; 223(Pt A): 67-76, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36336158

RESUMO

Single helical ß-glucan is a one-dimensional host that can form a hybrid helix with DNAs/RNAs as delivery systems. However, unmodified ß-glucan has a gelling tendency and a single helical conformation is challenging to obtain. Therefore, in this study, we developed a ß-glucan formyl derivative with stable single helical conformation and no gelling tendency. Circular dichroism studies found that the formyl-ß-glucan could form a hybrid helix with DNA CpG-poly(dA). The hybrid helix delivery system showed improved activation on antigen-presenting cells, thereby upregulating the mRNA and protein levels of inflammatory factors, and had an immune-enhancing effect on ovalbumin (OVA) immunized mice. These results indicate that formyl-ß-glucan can be developed as a non-cationic supramolecular DNA delivery platform with low toxicity and high efficiency.


Assuntos
Vacinas , beta-Glucanas , Camundongos , Animais , beta-Glucanas/química , Poli A , Ovalbumina , DNA/química
11.
Int J Nanomedicine ; 17: 5303-5314, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36406639

RESUMO

Aim: This study focuses on constructing of an anti-inflammatory drug delivery system by encapsulation of berberine in the ß-glucan nanoparticles and evaluates its effect on treating ulcerative colitis. Methods: ß-Glucan and the anti-inflammatory drug berberine (BER) are self-assembled into nanoparticles to construct a drug delivery system (GLC/BER). The interaction between the drug and the carrier was characterized by circular dichroism, ultraviolet-visible spectroscopy, and dynamic light scattering. The anti-inflammatory effect of the GLC/BER was evaluated through a lipopolysaccharide (LPS)-induced RAW264.7 macrophage inflammation model and a sodium sulfate (DSS)-induced C57BL/6 mouse ulcerative colitis model. Results: The GLC/BER nanoparticles have a particle size of 80-120 nm and a high encapsulation efficiency of 37.8±4.21%. In the LPS-induced RAW264.7 macrophage inflammation model, GLC/BER significantly promoted the uptake of BER by RAW264.7 cells. RT-PCR and ELISA assay showed that it could significantly inhibit the inflammatory factors including IL-1ß, IL-6 and COX-2. Furthermore, GLC/BER shows inhibiting effect on the secretion of pro-inflammatory factors such as IL-1ß and IL-6, down-regulating the production of nitrite oxide; in animal studies, GLC/BER was found to exert a relieving effect on mice colitis. Conclusion: The study found that GLC/BER has an anti-inflammatory effect in vitro and in vivo, and the GLC carrier improves the potency and bioavailability of BER, providing a new type of nanomedicine for the treatment of colitis.


Assuntos
Berberina , Colite Ulcerativa , Colite , Nanopartículas , beta-Glucanas , Camundongos , Animais , Berberina/farmacologia , Berberina/uso terapêutico , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/tratamento farmacológico , Lipopolissacarídeos , Interleucina-6 , Camundongos Endogâmicos C57BL , Macrófagos , Colite/induzido quimicamente , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Inflamação/tratamento farmacológico
12.
Int J Biol Macromol ; 216: 528-536, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35809670

RESUMO

Chemical modification of polysaccharides is important for expanding their applications and gaining new insights into their structure-property relationships. Here we reported the synthesis, characterization, and anti-viral activities of laminarin acetyl derivatives. The chemical structure and chain conformation of acetylated laminarin were characterized by FT-IR, H1 NMR, AFM, UV-vis spectrum, and induced circular dichroism based on a modified Congo Red assay (ICD-CR assay). The inhibition effect of laminarin and its acetyl derivatives on HSV-1 was evaluated by viral plaque assay and virus-associated DNA/protein change. Acetylation modification was found to trigger the conformation transition of laminarin from triple helix to single helix, and the extent of transition can be tuned by the degree of substitution. The single helical acetylated laminarins were found to be stable in neutral aqueous solution and exhibited no cytotoxicity. However, the acetylated laminarin exhibited declined antiviral activity after modification.


Assuntos
Antivirais , Ésteres , Antivirais/farmacologia , Dicroísmo Circular , Glucanos/química , Glucanos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Front Plant Sci ; 13: 882884, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35909755

RESUMO

Salinity adversity has been a major environmental stressor for plant growth and reproduction worldwide. Semi-mangrove Clerodendrum inerme, a naturally salt-tolerant plant, can be studied as a successful example to understand the biological mechanism of saline resistance. Since it is a sophisticated and all-round scale process for plants to react to stress, our greenhouse study interpreted the response of C. inerme to salt challenge in the following aspects: morphology, osmotic protectants, ROS production and scavenging, ion homeostasis, photosynthetic efficiency, and transcriptome reprogramming. The results drew an overview picture to illustrate the tolerant performance of C. inerme from salt acclimatization (till medium NaCl level, 0.3 mol/L) to salinity stress (high NaCl level, 0.5 mol/L). The overall evaluation leads to a conclusion that the main survival strategy of C. inerme is globally reshaping metabolic and ion profiles to adapt to saline adversity. These findings uncover the defense mechanism by which C. inerme moderates its development rate to resist the short- and long-term salt adversity, along with rebalancing the energy allocation between growth and stress tolerance.

14.
ACS Appl Mater Interfaces ; 13(31): 36747-36756, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34325510

RESUMO

The bacterial exopolysaccharide Curdlan has a unique collagen-like triple helical structure and immune-modulation activities. Although there have been several types of Curdlan gels reported for antibacterial or wound healing purposes, none of them exhibit favorable mechanical properties for clinically applicable wound healing materials. Herein, we present a two-step approach for preparing Ag-embedded Curdlan hydrogels that are highly soft but are very stretchable compared with common polysaccharide-based hydrogels. Ag ions were first reduced in a diluted Curdlan solution to form AgNP-decorated triple helices. Then, the aqueous solution consisting of Curdlan/Ag nanoparticles was mixed with a dimethyl sulfoxide solution consisting of a high concentration of Curdlan. This mixing triggered the conformation transformation of Curdlan random coils into triple helices, and then the helices were further packed into semicrystalline nanofibrils of ∼20 nm in diameter. Due to the presence of semicrystalline fibrils, this novel Curdlan hydrogel exhibits a fracture strain of ∼350% and fracture stress of ∼0.2 MPa at a water content of ∼97%. This nanofibril hydrogel supported the attachment, spreading, and growth of fibroblasts and effectively inhibited the growth of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Moreover, the hydrogels downregulated NO production and proinflammatory gene expression levels in lipopolysaccharide (LPS)-stimulated macrophages but did not change the anti-inflammatory gene expression levels in IL-4-stimulated macrophages. In an animal study, these hydrogels accelerated wound healing in a bacteria-infected mice skin wound model. These results validate the further development of Curdlan/AgNPs nanofibril hydrogels in clinical wound management.


Assuntos
Antibacterianos/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Hidrogéis/uso terapêutico , Nanofibras/uso terapêutico , Prata/uso terapêutico , beta-Glucanas/uso terapêutico , Animais , Antibacterianos/química , Antibacterianos/toxicidade , Anti-Inflamatórios/química , Anti-Inflamatórios/toxicidade , Configuração de Carboidratos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Hidrogéis/química , Hidrogéis/toxicidade , Masculino , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Nanopartículas Metálicas/toxicidade , Camundongos , Camundongos Endogâmicos BALB C , Células NIH 3T3 , Nanofibras/química , Nanofibras/toxicidade , Prata/química , Prata/toxicidade , Pele/patologia , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Infecções Cutâneas Estafilocócicas/patologia , Staphylococcus aureus/efeitos dos fármacos , Resistência à Tração , Cicatrização/efeitos dos fármacos , beta-Glucanas/química , beta-Glucanas/toxicidade
15.
Physiol Plant ; 133(2): 254-65, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18346082

RESUMO

Petal pigmentation is the most important aspect in natural flower coloration. In the present study, the inhibition of petal pigmentation by exogenous ammonium was investigated. Ray floret petals detached from inflorescences of Gerbera hybrida (Shenzhen No. 5) were cultured in vitro on media supplied with different forms of nitrogen and its assimilated compounds. The expression of a set of genes involved in anthocyanin biosynthesis and regulation was determined by Northern blotting assay. It was found that ammonium (NH4+), not nitrate (NO3-), in millimolar concentrations inhibited anthocyanin accumulation. The expressions of Gerbera chalcone synthase 1 (GCHS1), Gerbera chalcone synthase 2 (GCHS2) and Gerbera dihydroflavonol-4-reductase (GDFR) decreased, while six other related genes showed no significant changes after NH4+ treatment. Further studies on NH4+ function indicated that glutamine (Gln) acted as a downstream factor of NH4+ to suppress petal pigmentation. Both exogenous Gln and NH4+ were found to inhibit anthocyanin accumulation in the petals, and the application of Gln was also found to inhibit the expressions of GCHS1, GCHS2 and GDFR. The application of NH4+ also resulted in an increase in the activity of Gerbera glutamine synthetase (EC 6.3.1.2) along with a rapid increase of Gln content. When methionine sulfoximine, an inhibitor of glutamine synthetase (GS), was added, it was found to block the NH4+-induced inhibition of pigmentation. From these experiments, we conclude that the NH4+-induced suppression of petal pigmentation is not because of NH4+ toxicity, and the inhibition of pigmentation caused by the addition of exogenous NH4+ is the result of its assimilation into Gln.


Assuntos
Asteraceae/efeitos dos fármacos , Asteraceae/metabolismo , Flores/efeitos dos fármacos , Flores/metabolismo , Pigmentação/efeitos dos fármacos , Compostos de Amônio Quaternário/farmacologia , Antocianinas/biossíntese , Asteraceae/enzimologia , Asteraceae/genética , Azasserina/farmacologia , Células Cultivadas , Flores/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Glutamato-Amônia Ligase/metabolismo , Ácido Glutâmico/farmacologia , Glutamina/farmacologia , Metionina Sulfoximina/farmacologia , Fatores de Tempo
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