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1.
Opt Express ; 32(11): 19645-19654, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38859094

RESUMO

Over the past decade, perovskite solar cells (PSCs) have attracted enormous attention due to their high performance. One key to fabricating high-quality perovskite films lies in controlling the volatilization rate of residual solvents during the annealing process. This study systematically investigates how different protective substrates affect the volatilization rate of residual solvent in perovskite films. By adjusting the direction and rate of evaporation, the supersaturation time of the solution was precisely controlled, leading to effective recrystallization of the grains. Concurrently, the annealing time was optimized to enhance film quality further. This optimization aimed to increase crystallinity, reduce defects, and thereby minimize non-radiative recombination centers. Implementing these methodologies, particularly the use of filter paper as a protective substrate during a 2-minute annealing process, significantly improved the fill factor (FF) and open-circuit voltage (VOC) of the PSCs. This led to a remarkable 5.26% improvement in power conversion efficiency (PCE) compared to control devices. The strategies employed in this work demonstrate significant potential in improving PSC film quality. This approach not only advances our understanding of film formation dynamics but also provides a practical guideline for future PSC fabrication.

2.
Mol Biol Rep ; 51(1): 634, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38727746

RESUMO

BACKGROUND: The Chinese soft-shelled turtle, Pelodiscus sinensis, exhibits distinct sexual dimorphism, with the males growing faster and larger than the females. During breeding, all-male offspring can be obtained using 17ß-estradiol (E2). However, the molecular mechanisms underlying E2-induced sexual reversal have not yet been elucidated. Previous studies have investigated the molecular sequence and expression characteristics of estrogen receptors (ERs). METHODS AND RESULTS: In this study, primary liver cells and embryos of P. sinensis were treated with ER agonists or inhibitors. Cell incubation experiments revealed that nuclear ERs (nERs) were the main pathway for the transmission of estrogen signals. Our results showed that ERα agonist (ERα-ag) upregulated the expression of Rspo1, whereas ERα inhibitor (ERα-Inh) downregulated its expression. The expression of Dmrt1 was enhanced after ERα-Inh + G-ag treatment, indicating that the regulation of male genes may not act through a single estrogen receptor, but a combination of ERs. In embryos, only the ERα-ag remarkably promoted the expression levels of Rspo1, Wnt4, and ß-catenin, whereas the ERα-Inh had a suppressive effect. Additionally, Dmrt1, Amh, and Sox9 expression levels were downregulated after ERß inhibitor (ERß-Inh) treatment. GPER agonist (G-ag) has a significant promotion effect on Rspo1, Wnt4, and ß-catenin, while the inhibitor G-Inh does not affect male-related genes. CONCLUSIONS: Overall, these results suggest that ERs play different roles during sexual reversal in P. sinensis and ERα may be the main carrier of estrogen-induced sexual reversal in P. sinensis. Further studies need to be performed to analyze the mechanism of ER action.


Assuntos
Receptores de Estrogênio , Tartarugas , Animais , Tartarugas/genética , Tartarugas/metabolismo , Masculino , Feminino , Receptores de Estrogênio/metabolismo , Receptores de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Receptor alfa de Estrogênio/genética , Estradiol/farmacologia , Estradiol/metabolismo , Caracteres Sexuais , Estrogênios/metabolismo , Estrogênios/farmacologia , beta Catenina/metabolismo , beta Catenina/genética , Fígado/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/efeitos dos fármacos
3.
Appl Microbiol Biotechnol ; 108(1): 89, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38194145

RESUMO

The industrial bacterium Bacillus licheniformis has long been used as a microbial factory for the production of enzymes due to its ability to secrete copious amounts of native extracellular proteins and its generally regarded as safe (GRAS) status. However, most attempts to use B. licheniformis to produce heterologous and cytoplasmic enzymes primarily via the general secretory (Sec) pathway have had limited success. The twin-arginine transport (Tat) pathway offers a promising alternative for the extracellular export of Sec-incompatible proteins because it transports full, correctly folded proteins. However, compared to the Sec pathway, the yields of the Tat pathway have historically been too low for commercial use. To improve the export efficiency of the Tat pathway, we identified the optimal Tat-dependent signal peptides and increased the abundance of the Tat translocases, the signal peptidase (SPase), and the intracellular chaperones. These strategic modifications significantly improved the Tat-dependent secretion of the cytoplasmic enzyme arginase into the culture medium using B. licheniformis. The extracellular enzymatic activity of arginase showed a 5.2-fold increase after these modifications. Moreover, compared to the start strain B. licheniformis 0F3, the production of extracellular GFP was improved by 3.8 times using the strategic modified strain B. licheniformis 0F13, and the extracellular enzymatic activity of SOX had a 1.3-fold increase using the strain B. licheniformis 0F14. This Tat-based production chassis has the potential for enhanced production of Sec-incompatible enzymes, therefore expanding the capability of B. licheniformis as an efficient cellular factory for the production of high-value proteins. KEY POINTS: • Systematic genetic modification of Tat-pathway in B. licheniformis. • Significant enhancement of the secretion capacity of Tat pathway for delivery the cytoplasmic enzyme arginase. • A new platform for efficient extracellular production of Sec-incompatible enzymes.


Assuntos
Arginase , Bacillus licheniformis , Via Secretória/genética , Bacillus licheniformis/genética , Citoplasma , Citosol
4.
Angew Chem Int Ed Engl ; 63(12): e202316394, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38248139

RESUMO

Advances in targeted covalent inhibitors (TCIs) have been made by using lysine-reactive chemistries. Few aminophiles possessing balanced reactivity/stability for the development of cell-active TCIs are however available. We report herein lysine-reactive activity-based probes (ABPs; 2-14) based on the chemistry of aryl fluorosulfates (ArOSO2 F) capable of global reactivity profiling of the catalytic lysine in human kinome from mammalian cells. We concurrently developed reversible covalent ABPs (15/16) by installing salicylaldehydes (SA) onto a promiscuous kinase-binding scaffold. The stability and amine reactivity of these probes exhibited a broad range of tunability. X-ray crystallography and mass spectrometry (MS) confirmed the successful covalent engagement between ArOSO2 F on 9 and the catalytic lysine of SRC kinase. Chemoproteomic studies enabled the profiling of >300 endogenous kinases, thus providing a global landscape of ligandable catalytic lysines of the kinome. By further introducing these aminophiles into VX-680 (a noncovalent inhibitor of AURKA kinase), we generated novel lysine-reactive TCIs that exhibited excellent in vitro potency and reasonable cellular activities with prolonged residence time. Our work serves as a general guide for the development of lysine-reactive ArOSO2 F-based TCIs.


Assuntos
Lisina , Fosfotransferases , Animais , Humanos , Lisina/química , Ligação Proteica , Espectrometria de Massas , Catálise , Mamíferos/metabolismo
5.
J Am Chem Soc ; 2023 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-36774655

RESUMO

Lysine-targeting irreversible covalent inhibitors have attracted growing interests in recent years, especially in the fields of kinase research. Despite encouraging progress, few chemistries are available to develop inhibitors that are exclusively lysine-targeting, selective, and cell-active. We report herein a 2-ethynylbenzaldehyde (EBA)-based, lysine-targeting strategy to generate potent and selective small-molecule inhibitors of ABL kinase by selectively targeting the conserved catalytic lysine in the enzyme. We showed the resulting compounds were cell-active, capable of covalently engaging endogenous ABL kinase in K562 cells with long-residence time and few off-targets. We further validated the generality of this strategy by developing EBA-based irreversible inhibitors against EGFR (a kinase) and Mcl-1 (a nonkinase) that covalently reacted with the catalytic and noncatalytic lysine within each target.

6.
J Am Chem Soc ; 145(16): 9334-9342, 2023 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-37068218

RESUMO

Triple-negative breast cancer (TNBC) is highly aggressive with a poor clinical prognosis and no targeted therapy. The c-Myc protein is a master transcription factor and a potential therapeutic target for TNBC. In this study, we develop a PROTAC (PROteolysis TArgeting Chimera) based on TNA (threose nucleic acid) and DNA that effectively targets and degrades c-Myc. The TNA aptamer is selected in vitro to bind the c-Myc/Max heterodimer and appended to the E-box DNA sequence to create a high-affinity, biologically stable bivalent binder. The TNA-E box-pomalidomide (TEP) conjugate specifically degrades endogenous c-Myc/Max, inhibits TNBC cell proliferation, and sensitizes TNBC cells to the cyclin-dependent kinase inhibitor palbociclib in vitro. In a mouse TNBC model, combination therapy with TEP and palbociclib potently suppresses tumor growth. This study offers a promising nucleic acid-based PROTAC modality for both chemical biology studies and therapeutic interventions of TNBC.


Assuntos
Antineoplásicos , Neoplasias de Mama Triplo Negativas , Animais , Humanos , Camundongos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Fatores de Transcrição , Neoplasias de Mama Triplo Negativas/patologia , Genes myc
7.
Angew Chem Int Ed Engl ; 61(26): e202203878, 2022 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-35438229

RESUMO

Despite recent interests in developing lysine-targeting covalent inhibitors, no general approach is available to create such compounds. We report herein a general approach to develop cell-active covalent inhibitors of protein kinases by targeting the conserved catalytic lysine residue using key SuFEx and salicylaldehyde-based imine chemistries. We validated the strategy by successfully developing (irreversible and reversible) covalent inhibitors against BCR-ABL kinase. Our lead compounds showed high levels of selectivity in biochemical assays, exhibited nanomolar potency against endogenous ABL kinase in cellular assays, and were active against most drug-resistant ABL mutations. Among them, the salicylaldehyde-containing A5 is the first-ever reversible covalent ABL inhibitor that possessed time-dependent ABL inhibition with prolonged residence time and few cellular off-targets in K562 cells. Bioinformatics further suggested the generality of our strategy against the human kinome.


Assuntos
Proteínas de Fusão bcr-abl , Leucemia Mielogênica Crônica BCR-ABL Positiva , Humanos , Células K562 , Lisina/metabolismo , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia
8.
Small ; 16(34): e2002887, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32697420

RESUMO

Perovskite solar cells (PSCs) have attracted unprecedented attention due to their rapidly rising photoelectric conversion efficiency (PCE). In order to further improve the PCE of PSCs, new possible optimization path needs to be found. Here, quasi-heteroface PSCs (QHF-PSCs) is designed by a double-layer perovskite film. Such brand new PSCs have good carrier separation capabilities, effectively suppress the nonradiative recombination of the PSCs, and thus greatly improve the open-circuit voltage and PCE. The root cause of the performance improvement is the benefit from the additional built-in electric field, which is confirmed by measuring the external quantum efficiency under applied electric field and Kelvin probe force microscope. Meanwhile, an intermediate band gap perovskite layer can be obtained simply by combining a wide band gap perovskite layer with a narrow band gap perovskite layer. Tunability of the band gap is obtained by varying the film thicknesses of the narrow and wide band gap layers. This phenomenon is quite different from traditional inorganic solar cells, whose band gap is determined only by the narrowest band gap layer. It is believed that these QHF-PSCs will be an effective strategy to further enhance PCE in PSCs and provide basis to further understand and develop the perovskite materials platform.

9.
J Transl Med ; 17(1): 29, 2019 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-30654801

RESUMO

BACKGROUND: We set out to determine if the administration of subcutaneous (SQ) ALT-803 was non-inferior to standard intravesical BCG treatment in a carcinogen induced mouse (C57BL/6J) bladder cancer model. METHODS: Using this well-established carcinogen induced mouse model, we studied the effects of various dosing schemas of ALT-803 (SQ alone, SQ with intravesical BCG, intravesical alone, intravesical with intravesical BCG) compared to intravesical BCG alone (positive control) and PBS (negative control). The non-inferiority margin for the difference in bladder weight, as a surrogate for tumor mass, was defined as 7%. RESULTS: All treatment groups (i.e., ALT-803 SQ alone, ALT-803 SQ with intravesical BCG, ALT-803 intravesical alone, ALT-803 intravesical with intravesical BCG and intravesical BCG alone) demonstrated a significant reduction in tumor burden as evident by bladder weights and H&E stain (p < 0.005). Non-inferiority tests between the intravesical BCG alone group and the additional treatment groups showed that SQ ALT-803 alone (p = 0.04) and BCG plus SQ ALT-803 (p = 0.009) were non-inferior to intravesical BCG alone. In this model, we did not see an appreciable infiltration of CD4+ T, CD8+ T or CD161/KLRB1+ natural killer (NK) cells in the bladder/tumor. When assessing peripheral blood mononuclear cells, SQ ALT-803 alone resulted in a robust induction of CD8+ T cells (p < 0.01), NKG2D+ NK cells (p < 0.005) and CD3+/NKG2D+ NKT cells (p < 0.005) compared to other groups, while in splenic tissue, SQ ALT-803 alone resulted in a robust induction of CD3+/NKG2D+ NKT cells (p < 0.005) compared to other groups. CONCLUSION: Subcutaneous ALT-803 treatment alone or in combination with intravesical BCG was well tolerated and was not inferior to intravesical BCG alone. CD8+ T, NKG2D+ NK and CD3+/NKG2D+ NKT cell induction along with induction of key cytokines remain steadfast mechanisms behind ALT-803. The enhanced therapeutic index seen with BCG and ALT-803, administered SQ or intravesically, provides a powerful justification for the further development of these regimens.


Assuntos
Interleucina-15/agonistas , Proteínas/administração & dosagem , Proteínas/uso terapêutico , Neoplasias da Bexiga Urinária/tratamento farmacológico , Animais , Citocinas/sangue , Citocinas/urina , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Feminino , Interleucina-15/metabolismo , Linfócitos/metabolismo , Camundongos Endogâmicos C57BL , Mycobacterium bovis , Proteínas/farmacologia , Proteínas Recombinantes de Fusão , Resultado do Tratamento , Neoplasias da Bexiga Urinária/sangue , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/urina
11.
Appl Microbiol Biotechnol ; 103(10): 4003-4015, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30923871

RESUMO

Poly-γ-glutamic acid (γ-PGA) is an extracellularly produced biodegradable polymer, which has been widely used as agricultural fertilizer, mineral fortifier, cosmetic moisturizer, and drug carrier. This study firstly discovered that lichenysin, as a biosurfactant, showed the capability to enhance γ-PGA production in Bacillus licheniformis. The exogenous addition of lichenysin improved the γ-PGA yield up to 17.9% and 21.9%, respectively, in the native strain B. licheniformis WX-02 and the lichenysin-deficient strain B. licheniformis WX02-ΔlchAC. The capability of intracellular biosynthesis of lichenysin was positively correlated with γ-PGA production. The yield of γ-PGA increased by 25.1% in the lichenysin-enhanced strain B. licheniformis WX02-Psrflch and decreased by 12.2% in the lichenysin-deficient strain WX02-ΔlchAC. Analysis of key enzyme activities and gene expression in the TCA cycle, precursor glutamate synthesis, and γ-PGA synthesis pathway revealed that the existence of lichenysin led to increased γ-PGA via shifting the carbon flux in the TCA cycle towards glutamate and γ-PGA biosynthetic pathways, minimizing by-product formation, and facilitating the uptake of extracellular substrates and the polymerization of glutamate to γ-PGA. Insight into the mechanisms of enhanced production of γ-PGA by lichenysin would define the essential parameters involved in γ-PGA biosynthesis and provide the basis for large-scale production of γ-PGA.


Assuntos
Bacillus licheniformis/efeitos dos fármacos , Bacillus licheniformis/metabolismo , Vias Biossintéticas/efeitos dos fármacos , Lipoproteínas/metabolismo , Peptídeos Cíclicos/metabolismo , Ácido Poliglutâmico/análogos & derivados , Tensoativos/metabolismo , Carbono/metabolismo , Análise do Fluxo Metabólico , Ácido Poliglutâmico/biossíntese
12.
Cell Physiol Biochem ; 44(6): 2201-2211, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29253845

RESUMO

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) has been regarded as a risk factor for thrombosis and atherosclerosis. Since it has been shown that PAI-1 can activate macrophages through Toll-like receptor-4, we sought to investigate the role of PAI-1 in the tumor microenvironment. METHODS: The expression and distribution patterns of PAI-1 and transforming growth factor beta (TGF-ß) were measured in 60 non-small cell lung cancer (NSCLC) tumors. A statistical correlation analysis was performed between PAI-1 and TGF-ß expression and distribution in each tumor. The distribution of tumor-associated macrophages (TAMs) was also measured and its correlation to PAI-1 levels was analyzed. Levels of secreted CCL-17, CCL-22, IL-6 and TGF-ß were measured in cell cultures of human macrophage cell lines THP-1 and U937 treated with PAI-1. Levels of secreted PAI-1 were monitored in cell cultures of human NSCLCs cell lines 95D and A549 treated with TGF-ß. Secreted proteins were measured in cell culture supernatants using ELISA. Changes in downstream signaling pathways were investigated using western blot. RESULTS: PAI-1 and TGF-ß were found to be overexpressed in human NSCLCs. PAI-1 expression was tightly correlated to TGF-ß expression as well as the percentage of TAMs. PAI-1 treatment increased the expression of TAM-associated cytokines and chemokines, including CCL-17, CCL-22, and IL-6. PAI-1 treatment was also observed to enhance TGF-ß expression in macrophage cell lines through an IL-6 autocrine/paracrine manner. The effects on TGF-ß expression were blocked by NF-κB and STAT3 inhibition. Interestingly, TGF-ß also increased levels of secreted PAI-1 in NSCLC cells through SMAD3-dependent signaling, therefore resulting in a feed-forward loop. However, this loop could be blocked by NF-κB, STAT3 and SMAD3 signaling inhibition, as well as treatment with a high concentration of TGF-ß. CONCLUSION: PAI-1 and TGF-ß promote NSCLC tumor cells and TAMs and might be valuable targets for cancer immunosuppression.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/imunologia , Tolerância Imunológica , Neoplasias Pulmonares/imunologia , Macrófagos/imunologia , Inibidor 1 de Ativador de Plasminogênio/imunologia , Fator de Crescimento Transformador beta1/imunologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Feminino , Humanos , Interleucina-6/análise , Interleucina-6/imunologia , Pulmão/imunologia , Pulmão/patologia , Neoplasias Pulmonares/patologia , Macrófagos/patologia , Masculino , NF-kappa B/análise , NF-kappa B/imunologia , Inibidor 1 de Ativador de Plasminogênio/análise , Receptor 4 Toll-Like/análise , Receptor 4 Toll-Like/imunologia , Fator de Crescimento Transformador beta1/análise
13.
Microb Cell Fact ; 16(1): 70, 2017 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-28438200

RESUMO

BACKGROUND: Signal peptide peptidases play an important role in the removal of remnant signal peptides in the cell membrane, a critical step for extracellular protein production. Although these proteins are likely a central component for extracellular protein production, there has been a lack of research on whether protein secretion could be enhanced via overexpression of signal peptide peptidases. RESULTS: In this study, both nattokinase and α-amylase were employed as prototypical secreted target proteins to evaluate the function of putative signal peptide peptidases (SppA and TepA) in Bacillus licheniformis. We observed dramatic decreases in the concentrations of both target proteins (45 and 49%, respectively) in a sppA deficient strain, while the extracellular protein yields of nattokinase and α-amylase were increased by 30 and 67% respectively in a strain overexpressing SppA. In addition, biomass, specific enzyme activities and the relative gene transcriptional levels were also enhanced due to the overexpression of sppA, while altering the expression levels of tepA had no effect on the concentrations of the secreted target proteins. CONCLUSIONS: Our results confirm that SppA, but not TepA, plays an important functional role for protein secretion in B. licheniformis. Our results indicate that the sppA overexpression strain, B. licheniformis BL10GS, could be used as a promising host strain for the industrial production of heterologous secreted proteins.


Assuntos
Ácido Aspártico Endopeptidases/genética , Bacillus licheniformis/genética , Expressão Gênica , Subtilisinas/metabolismo , alfa-Amilases/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Bacillus licheniformis/enzimologia , Bacillus licheniformis/metabolismo , Biomassa , Sinais Direcionadores de Proteínas/genética , Transporte Proteico , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Subtilisinas/genética , Transcrição Gênica , alfa-Amilases/genética
14.
Appl Microbiol Biotechnol ; 101(16): 6375-6383, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28601894

RESUMO

Lichenysin is categorized into the family of lipopeptide biosurfactants and has a variety of applications in the petroleum industry, bioremediation, pharmaceuticals, and the food industry. Currently, large-scale production is limited due to the low yield. This study found that lichenysin production was repressed by supplementation of extracellular amino acids. The global transcriptional factor CodY was hypothesized to prevent lichenysin biosynthesis under an amino acid-rich condition in Bacillus licheniformis. Thus, the codY null strain was constructed, and lichenysin production was increased by 31.0% to 2356 mg/L with the addition of precursor amino acids, and the lichenysin production efficiency was improved by 42.8% to 98.2 mg/L• h. Correspondingly, the transcription levels of the lichenysin synthetase gene lchAA, and its corresponding regulator genes comA, degQ, and degU, were upregulated. Also, the codY deletion enhanced biosynthesis of lichenysin precursor amino acids (Gln, Ile, Leu, and Val) and reduced the formation of byproducts, acetate, acetoin, and 2,3-butanediol. This study firstly reported that lichenysin biosynthesis was negatively regulated by CodY and lichenysin production could be further improved with the precursor amino acid amendment in the codY null strain.


Assuntos
Aminoácidos/farmacologia , Bacillus licheniformis/efeitos dos fármacos , Bacillus licheniformis/metabolismo , Lipoproteínas/biossíntese , Peptídeos Cíclicos/biossíntese , Fatores de Transcrição/deficiência , Bacillus licheniformis/genética , Proteínas de Bactérias/genética , Proteínas de Ligação a DNA/genética , Regulação Bacteriana da Expressão Gênica , Ligases/genética , Transativadores/genética , Fatores de Transcrição/genética
15.
Appl Microbiol Biotechnol ; 101(19): 7155-7164, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28804802

RESUMO

Bacillus licheniformis WX-02 is a well-studied strain to produce poly-γ-glutamic acid (γ-PGA) with numerous applications. This study is to improve WX-02 strain's capability of assimilating glycerol, a major byproduct of biofuels industries, through metabolic manipulation. Through gene knockout, the GlpK pathway was identified as the sole functional glycerol catabolism pathway, while the DhaK pathway was inactive for this strain under either aerobic or anaerobic conditions. The enhancement of glycerol utilization was attempted by substituting the native glpFK promoter with the constitutive promoter (P43), ytzE promoter (PytzE), and bacABC operon promoter (PbacA), respectively. The glycerol consumptions of the corresponding mutant strains WX02-P43glpFK, WX02-PytzEglpFK, and WX02-PbacAglpFK were 30.9, 26.42, and 18.8% higher than that of the WX-02 strain, respectively. The γ-PGA concentrations produced by the three mutant strains were 33.71, 23.39, and 30.05% higher than that of WX-02 strain, respectively. When biodiesel-derived crude glycerol was used as the carbon source, the mutant WX02-P43glpFK produced 16.63 g L-1 of γ-PGA, with a productivity of 0.35 g L-1 h-1. Collectively, this study demonstrated that glycerol can be used as an effective substrate for producing γ-PGA by metabolic engineering B. licheniformis strains.


Assuntos
Bacillus licheniformis/metabolismo , Glicerol/metabolismo , Engenharia Metabólica , Ácido Poliglutâmico/análogos & derivados , Bacillus licheniformis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cromossomos Bacterianos/genética , Cromossomos Bacterianos/metabolismo , Deleção de Genes , Técnicas de Inativação de Genes , Óperon , Ácido Poliglutâmico/biossíntese , Regiões Promotoras Genéticas
16.
World J Microbiol Biotechnol ; 33(5): 84, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28378222

RESUMO

Nattokinase (EC 3.4.21.62) is a profibrinolytic serine protease with a potent fibrin-degrading activity, and it has been produced by many host strains. Compared to other fibrinolytic enzymes (urokinase, t-PA and streprokinase), nattokinase shows the advantages of having no side effects, low cost and long life-time, and it has the potential to be used as a drug for treating cardiovascular disease and served as a functional food additive. In this review, we focused on screening of producing strains, genetic engineering, fermentation process optimization for microbial nattokinase production, and the extraction and purification of nattokinase were also discussed in this particular chapter. The selection of optimal nattokinase producing strain was the crucial starting element for improvement of nattokinase production. Genetic engineering, protein engineering, fermentation optimization and process control have been proved to be the effective strategies for enhancement of nattokinase production. Also, extraction and purification of nattokinase are critical for the quality evaluation of nattokinase. Finally, the prospect of microbial nattokinase production was also discussed regarding the recent progress, challenge, and trends in this field.


Assuntos
Bactérias/metabolismo , Engenharia Genética/métodos , Subtilisinas/isolamento & purificação , Bactérias/classificação , Fermentação , Microbiologia de Alimentos , Humanos , Subtilisinas/metabolismo
17.
J Bacteriol ; 197(7): 1276-87, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25645554

RESUMO

UNLABELLED: In the bacterium Myxococcus xanthus, starvation triggers the formation of multicellular fruiting bodies containing thousands of stress-resistant spores. Recent work showed that fruiting body development is regulated by a cascade of transcriptional activators called enhancer binding proteins (EBPs). The EBP Nla6 is a key component of this cascade; it regulates the promoters of other EBP genes, including a downstream-functioning EBP gene that is crucial for sporulation. In recent expression studies, hundreds of Nla6-dependent genes were identified, suggesting that the EBP gene targets of Nla6 may be part of a much larger regulon. The goal of this study was to identify and characterize genes that belong to the Nla6 regulon. Accordingly, a direct repeat [consensus, C(C/A)ACGNNGNC] binding site for Nla6 was identified using in vitro and in vivo mutational analyses, and the sequence was subsequently used to find 40 potential developmental promoter (88 gene) targets. We showed that Nla6 binds to the promoter region of four new targets (asgE, exo, MXAN2688, and MXAN3259) in vitro and that Nla6 is important for their normal expression in vivo. Phenotypic studies indicate that all of the experimentally confirmed targets of Nla6 are primarily involved in sporulation. These targets include genes involved in transcriptional regulation, cell-cell signal production, and spore differentiation and maturation. Although sporulation occurs late in development, all of the developmental loci analyzed here show an Nla6-dependent burst in expression soon after starvation is induced. This finding suggests that Nla6 starts preparing cells for sporulation very early in the developmental process. IMPORTANCE: Bacterial development yields a remarkable array of complex multicellular forms. One such form, which is commonly found in nature, is a surface-associated aggregate of cells known as a biofilm. Mature biofilms are structurally complex and contain cells that are highly resistant to antibacterial agents. When starving, the model bacterium Myxococcus xanthus forms a biofilm containing a thin mat of cells and multicellular structures that house a highly resistant cell type called a myxospore. Here, we identify the promoter binding site of the transcriptional activator Nla6, identify genes in the Nla6 regulon, and show that several of the genes in the Nla6 regulon are important for production of stress-resistant spores in starvation-induced M. xanthus biofilms.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Myxococcus xanthus/fisiologia , Mutação , Myxococcus xanthus/genética , Myxococcus xanthus/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Transdução de Sinais , Esporos Bacterianos/fisiologia
18.
Glycoconj J ; 32(3-4): 113-8, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25796617

RESUMO

Liver glycogen (involved in maintaining blood-sugar levels) is a hyperbranched glucose polymer containing ß particles (diameter ~20 nm), which can form composite α particles (diameter ~50-300 nm), and includes a small but significant amount of bound protein. Size distributions of glycogen from livers of healthy and diabetic mice were examined using size-exclusion chromatography with two separate eluents: aqueous eluent and dimethylsulfoxide (DMSO) eluent. Morphologies were examined with transmission electron microscopy. Diabetic glycogen (DG) exhibited many α particles in the mild water-based solvent, but in DMSO, which breaks H bonds, these degraded to ß particles; α particles however were always present in healthy glycogen (HG). This DG fragility shows the binding of ß into α particles is different in HG and DG. The diabetic α particle fragility may be involved with the uncontrolled blood-sugar release symptomatic of diabetes: small ß particles degrade more easily to glucose than α particles. This has implications for diabetes management.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Glicogênio/química , Fígado/química , Animais , Cromatografia em Gel , Feminino , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Transmissão
20.
Chin Med J (Engl) ; 137(3): 338-349, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38105538

RESUMO

BACKGROUND: Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer associated with poor prognosis and limited treatment options. The androgen receptor (AR) has emerged as a potential therapeutic target for luminal androgen receptor (LAR) TNBC. However, multiple studies have claimed that anti-androgen therapy for AR-positive TNBC only has limited clinical benefits. This study aimed to investigate the role of AR in TNBC and its detailed mechanism. METHODS: Immunohistochemistry and TNBC tissue sections were applied to investigate AR and nectin cell adhesion molecule 4 (NECTIN4) expression in TNBC tissues. Then, in vitro and in vivo assays were used to explore the function of AR and estrogen receptor beta (ERß) in TNBC. Chromatin immunoprecipitation sequencing (ChIP-seq), co-immunoprecipitation (co-IP), molecular docking method, and luciferase reporter assay were performed to identify key molecules that affect the function of AR. RESULTS: Based on the TNBC tissue array analysis, we revealed that ERß and AR were positive in 21.92% (32/146) and 24.66% (36/146) of 146 TNBC samples, respectively, and about 13.70% (20/146) of TNBC patients were ERß positive and AR positive. We further demonstrated the pro-tumoral effects of AR on TNBC cells, however, the oncogenic biology was significantly suppressed when ERß transfection in LAR TNBC cell lines but not in AR-negative TNBC. Mechanistically, we identified that NECTIN4 promoter -42 bp to -28 bp was an AR response element, and that ERß interacted with AR thus impeding the AR-mediated NECTIN4 transcription which promoted epithelial-mesenchymal transition in tumor progression. CONCLUSIONS: This study suggests that ERß functions as a suppressor mediating the effect of AR in TNBC prognosis and cell proliferation. Therefore, our current research facilitates a better understanding of the role and mechanisms of AR in TNBC carcinogenesis.


Assuntos
Androgênios , Neoplasias de Mama Triplo Negativas , Humanos , Androgênios/uso terapêutico , Receptor beta de Estrogênio/genética , Receptor beta de Estrogênio/metabolismo , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Receptores Androgênicos/uso terapêutico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Simulação de Acoplamento Molecular , Linhagem Celular Tumoral
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