RESUMEN
We report two bridging-diazene diiron complexes [Cp*Fe(8-quinolinethiolate)]2(µ-N2H2) (1-N2H2) and [Cp*Fe(1,2-Cy2PC6H4S)]2(µ-N2H2) (2-N2H2), synthesized by the reaction of hydrazine with the corresponding thiolate-based iron half-sandwich complex, [Cp*Fe(8-quinolinethiolate)]2 (1) and Cp*Fe(1,2-Cy2PC6H4S) (2). Crystallographic analysis reveals that the thiolate sites in 1-N2H2 and 2-N2H2 can engage in N-H···S hydrogen bonding with the diazene protons. 1-N2H2 is thermally stable in both solid and solution states, allowing for one-electron oxidation to afford a cationic diazene radical complex [1-N2H2]+ at room temperature. In contrast, 2-N2H2 tends to undergo N2H2/N2 transformation, leading to the formation of a Fe(III)-H species by the loss of N2. In addition to stabilizing HN=NH species through the hydrogen bonding, the thiolate-based ligands also seem to facilitate proton-coupled electron transfer, thereby promoting N-H cleavage.
RESUMEN
Organophosphate flame retardants (OPFRs) are widely used as substitutes for traditional brominated flame retardants, necessitating a reliable and sensitive method for biomonitoring their urinary metabolites to assess human exposure. This study conducted biomonitoring of 10 metabolites of OPFRs in 152 adults and assessed their association with oxidative stress biomarkers 8-hydroxydeoxyguanosine and 8-hydroxyguanosine. Urinary metabolites of OPFRs were released via enzymatic deconjugation. The addition of sodium chloride to the urine samples increases the ionic strength, inducing a salting-out effect that reduces the solubility of these compounds, thereby facilitating their extraction with a mixture of ethyl acetate and acetonitrile. Then, the metabolites of OPFRs were quantified by ultra-high performance liquid chromatography-tandem mass spectrometry, and we validated the method for linear range, precision, matrix effect, and method detection limit. The detection limit of the metabolites of OPFRs ranged from 0.01 to 0.2 µg/L, and these metabolites were detected with high frequencies ranging from 25.0 to 98.68% in the urine samples. The concentration of bis (2-chloroethyl) phosphate was significantly higher in males than in females, with the geometric mean concentration of 0.88 µg/L for males and 0.53 µg/L for females, respectively. Spearman correlation analysis revealed weak but statistically significant positive correlations among the urinary metabolites. Bayesian kernel machine regression analysis showed a significant positive association between elevated urinary concentrations of metabolites of OPFRs and increased oxidative stress levels. Di-n-butyl phosphate was identified as the metabolite that significantly contributed to the elevated level of 8-hydroxyguanosine.
Asunto(s)
Monitoreo Biológico , Retardadores de Llama , Límite de Detección , Extracción Líquido-Líquido , Compuestos Organofosforados , Estrés Oxidativo , Espectrometría de Masas en Tándem , Humanos , Retardadores de Llama/análisis , Retardadores de Llama/metabolismo , Espectrometría de Masas en Tándem/métodos , Femenino , Masculino , Cromatografía Líquida de Alta Presión/métodos , Adulto , Monitoreo Biológico/métodos , Compuestos Organofosforados/orina , Extracción Líquido-Líquido/métodos , Persona de Mediana Edad , Biomarcadores/orina , Adulto JovenRESUMEN
Exploring bidirectional CO2/HCO2- catalysis holds significant potential in constructing integrated (photo)electrochemical formate fuel cells for energy storage and applications. Herein, we report selective CO2/HCO2- electrochemical interconversion by exploiting the flexible coordination modes and rich redox properties of a versatile iron-thiolate platform, Cp*Fe(II)L (L = 1,2-Ph2PC6H4S-). Upon oxidation, this iron complex undergoes formate binding to generate a diferric formate complex, [(L-)2Fe(III)(µ-HCO2)Fe(III)]+, which exhibits remarkable electrocatalytic performance for the HCO2--to-CO2 transformation with a maximum turnover frequency (TOFmax) â¼103 s-1 and a Faraday efficiency (FE) â¼92(±4)%. Conversely, this iron system also allows for reduction at -1.85 V (vs Fc+/0) and exhibits an impressive FE â¼93 (±3)% for the CO2-to-HCO2- conversion. Mechanism studies revealed that the HCO2--to-CO2 electrocatalysis passes through dicationic [(L2)-â¢Fe(III)(µ-HCO2)Fe(III)]2+ generated by unconventional oxidation of the diferric formate species taking place at ligand L, while the CO2-to-HCO2- reduction involves a critical intermediate of [Fe(II)-H]- that was independently synthesized and structurally characterized.
RESUMEN
Parent amido complexes are crucial intermediates in ammonia-based transformations. We report a well-defined ferric ammine system [Cp*Fe(1,2-Ph2PC6H4NH)(NH3)]+ ([1-NH3]+), which processes electrocatalytic ammonia oxidation to N2 and H2 at a mild potential. Through establishing elementary e-/H+ conversions with the ferric ammine, a formal Fe(IV)-amido species, [1-NH2]+, together with its conjugated Lewis acid, [1-NH3]2+, was isolated and structurally characterized for the first time. Mechanism studies indicated that further oxidation of [1-NH2]+ induces the reaction of the parent amido unit with NH3. The formation of hydrazine is realized by the non-innocent nature of the phenylamido ligand that facilitates the concerted transfer of one proton and two electrons.
RESUMEN
Osteolysis is a common medical condition characterized by excessive activity of osteoclasts and bone resorption, leading to severe poor quality of life. It is essential to identify the medications that can effectively suppress the excessive differentiation and function of osteoclasts to prevent and reduce the osteolytic conditions. It has been reported that Carnosol (Car), isolated from rosemary and salvia, has anti-inflammatory, antioxidative, and anticancer effects, but its activity on osteolysis has not been determined. In this study, we found that Car has a strong inhibitory effect on the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation dose-dependently without any observable cytotoxicity. Moreover, Car can inhibit the RANKL-induced osteoclastogenesis and resorptive function via suppressing NFATc1, which is a result of affecting MAPK, NF-κB and Ca2+ signaling pathways. Moreover, the particle-induced osteolysis mouse model confirmed that Car could be effective for the treatment of bone loss in vivo. Taken together, by suppressing the formation and function of RANKL-induced osteoclast, Car, may be a therapeutic supplementary in the prevention or the treatment of osteolysis.
Asunto(s)
Abietanos/uso terapéutico , Osteogénesis , Osteólisis/inducido químicamente , Osteólisis/tratamiento farmacológico , Ligando RANK/farmacología , Titanio/efectos adversos , Abietanos/farmacología , Animales , Resorción Ósea/complicaciones , Resorción Ósea/genética , Resorción Ósea/patología , Señalización del Calcio/efectos de los fármacos , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Modelos Biológicos , Inhibidor NF-kappaB alfa/metabolismo , FN-kappa B/metabolismo , Factores de Transcripción NFATC/metabolismo , Osteoclastos/efectos de los fármacos , Osteoclastos/metabolismo , Osteoclastos/patología , Osteogénesis/efectos de los fármacos , Osteogénesis/genética , Osteólisis/genética , Osteólisis/patología , Proteolisis/efectos de los fármacos , Cráneo/efectos de los fármacos , Cráneo/patologíaRESUMEN
BACKGROUND: The increase of augmented level and bone cement dose are accompanied by the rising incidence of cement leakage (CL) of cement-augmented pedicle screw instrumentation (CAPSI). But the effect and potential risks of the application of CAPSI to osteoporotic lumbar degenerative disease (LDD) have not been studied in the case of multilevel fixation. This study aimed to investigate the effectiveness and potential complications of using multilevel CAPSI for patients with osteoporotic LDD. METHODS: A total of 93 patients with multilevel LDD were divided into the CAPSI group (46 subjects) and the conventional pedicle screw (CPS) group (47 subjects), including 75 cases for three levels and 18 cases for four levels. Relevant data were compared between two groups, including baseline data, clinical results, and complications. RESULTS: In the CAPSI group, a total of 336 augmented screws was placed bilaterally. The CL was observed in 116 screws (34.52%). Three cemented screws (0.89%) were found loosened during the follow-up and the overall fusion rate was 93.47%. For perioperative complications, two patients (4.35%) experienced pulmonary cement embolism (PCE), one patient augmented vertebral fracture, and three patients (6.52%) wound infection. And in the CPS group, thirty-three screws (8.46%) suffered loosening in cranial and caudal vertebra with a fusion rate of 91.49%. The operation time and hospital stay of CAPSI group were longer than the CPS group, but CAPSI group has a lower screw loosening percentage (P<0. 05). And in terms of blood loss, perioperative complications, fusion rate, and VAS and ODI scores at the follow-up times, there were no significant differences between the two groups. CONCLUSIONS: Patients with osteoporotic LDD underwent multilevel CPS fixation have a higher rate of screw loosening in the cranial and caudal vertebra. The application of cemented pedicle screws for multilevel LDD can achieve better stability and less screw loosening, but it also accompanied by longer operating time, higher incidence of CL, PCE and wound infections. Selective cement augmentation of cranial and caudal pedicle screws may be a worthy strategy to decrease the complications.
Asunto(s)
Cementos para Huesos/efectos adversos , Degeneración del Disco Intervertebral/cirugía , Vértebras Lumbares/cirugía , Tornillos Pediculares/efectos adversos , Fusión Vertebral/instrumentación , Absorciometría de Fotón , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Tiempo de Internación , Vértebras Lumbares/patología , Masculino , Persona de Mediana Edad , Tempo Operativo , Osteoporosis/complicaciones , Osteoporosis/diagnóstico por imagen , Fracturas Osteoporóticas/cirugía , Falla de Prótesis/tendencias , Embolia Pulmonar/epidemiología , Estudios Retrospectivos , Factores de Riesgo , Fracturas de la Columna Vertebral/cirugía , Infección de la Herida Quirúrgica/epidemiologíaRESUMEN
BACKGROUND: Polymethylmethacrylate (PMMA) is commonly used for cement-augmented pedicle screw instrumentation (CAPSI) to improve the fixation stability and reduce the risk of screw loosening in the osteoporotic thoracolumbar spine. Biomechanical researches have shown that various dose of cement (1-3 ml) can be injected to enhance screw stability. To date, there have been no studies on the relationship between adjacent segment degeneration and the volume of PMMA. This study aimed to explore the influence of CAPSI with different volumes of PMMA in osteoporotic lumbar vertebrae over adjacent segments by using finite element analysis. METHODS: Seven different finite element models were reconstructed and simulated under different loading conditions, including (1) an intact model, (2) three single-level CAPSI models with different volumes of PMMA (1, 1.73, and 2.5 ml), and (3) three double-level CAPSI models with different volumes of PMMA (1, 1.73, and 2.5 ml). To improve the accuracy of the finite element analysis, the models of the injectable pedicle screw and bone cement were created by using a three-dimensional scanning machine and the CAPSI patient's CT data, respectively. The range of motion (ROM), the stress of intervertebral discs, and the stress of facet in the adjacent segment were comparatively analyzed among the different models. RESULTS: The ROMs of the different segments were compared with experimental data, with good agreement under the different load conditions (21.3°, 13.55°, 13.99°, and 6.11° in flexion, extension, bending, and rotation at L3-S1 level, respectively). Compared with the intact model, the ROM, disc stresses, and facet stress in adjacent segments were found to be higher in the six operative models. Otherwise, with a larger volume of PMMA injected, the ROM, disc stresses, and facet stress slightly increased at the adjacent segment. However, the differences were insignificant with the biggest difference less than 3.8%. CONCLUSIONS: CAPSI could increase the incidence of disk degeneration in the adjacent segment, while within a certain range, different volumes of PMMA provided an approximate impact over the adjacent segment degeneration.
Asunto(s)
Tornillos Pediculares , Fusión Vertebral , Fenómenos Biomecánicos , Cementos para Huesos , Análisis de Elementos Finitos , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/cirugía , Polimetil Metacrilato , Rango del Movimiento Articular , Fusión Vertebral/efectos adversosRESUMEN
OBJECTIVE: To simultaneously increase the thermostability and catalytic activity of barley ß-amylase. METHODS: The amino acid sequences of various barley ß-amylases with different enzyme properties were aligned, two amino acid residues R115 and T387 were identified to be important for barley ß-amylase properties. R115C and T387V were then generated using site-directed and saturation mutagenesis. RESULTS: R115C and T387V mutants increased the enzyme catalytic activity and thermostability, respectively. After combinational mutagenesis, the T50 value and t(1/2,60oC) value of R115C/T387V mutant reached 59.4⯰C and 48.8â¯min, which were 3.6⯰C higher and 29.5â¯min longer than those of wild-type. The kcat/Km value of mutant R115C/T387V were 59.82/s·mM, which were 54.7% higher than that of wild-type. The increased surface hydrophobicity and newly formed strong hydrogen bonds and salt bridges might be responsible for the enzyme thermostability improvement while the two additional hydrogen bonds formed in the active center may lead to the catalytic property enhancement. CONCLUSIONS: The mutant R115C/T387V showed high catalytic activity and thermostability indicating great potential for application in industry.
Asunto(s)
Sustitución de Aminoácidos , Hordeum/enzimología , beta-Amilasa/química , beta-Amilasa/genética , beta-Amilasa/metabolismo , Arginina/genética , Estabilidad de Enzimas , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Conformación Proteica , Ingeniería de Proteínas , Alineación de Secuencia , Treonina/genéticaRESUMEN
Acetaldehyde is synthesized by yeast during the main fermentation period of beer production, which causes an unpleasant off-flavor. Therefore, there has been extensive effort toward reducing acetaldehyde to obtain a beer product with better flavor and anti-staling ability. In this study, we discovered that acetaldehyde production in beer brewing is closely related with the intracellular NADH equivalent regulated by the citric acid cycle. However, there was no significant relationship between acetaldehyde production and amino acid metabolism. A reverse engineering strategy to increase the intracellular NADH/NAD+ ratio reduced the final acetaldehyde production level, and vice versa. This work offers new insight into acetaldehyde metabolism and further provides efficient strategies for reducing acetaldehyde production by the regulating the intracellular NADH/NAD+ ratio through cofactor engineering.
Asunto(s)
Acetaldehído/metabolismo , Cerveza/microbiología , Ingeniería Metabólica/métodos , NAD/metabolismo , Genética Inversa/métodos , Saccharomyces/genética , Saccharomyces/metabolismo , FermentaciónRESUMEN
OBJECTIVE: To improve the aroma profile of beer by using metabolic engineering to increase the availability of cytosolic NADH in lager yeast. RESULTS: To alter NADH levels in lager yeast, the native FDH1 (YOR388C) encoding NAD+-dependent formate dehydrogenase was overexpressed in the yeast strain M14, yielding strain M-FDH1. This led to a simultaneous increase of NADH availability and NADH/NAD+ ratio in the M-FDH1 strain during fermentation. At the end of the main fermentation period, ethanol production by strain M-FDH1 was decreased by 13.2%, while glycerol production was enhanced by 129.4%, compared to the parental strain respectively. The production of esters and fusel alcohols by strains M14 and M-FDH1 was similar. By contrast, strain M-FDH1 generally produced less organic acids and off-flavor components than strain M14, improving the beer aroma. CONCLUSIONS: Increased NADH availability led to rerouting of the carbon flux toward NADH-consuming pathways and accelerated the NADH-dependent reducing reactions in yeast, greatly impacting the formation of aroma compounds and improving the beer aroma.
Asunto(s)
Cerveza/microbiología , Microbiología de Alimentos/métodos , Microbiología Industrial/métodos , Ingeniería Metabólica/métodos , NAD/metabolismo , Odorantes/análisis , Saccharomyces cerevisiae/metabolismo , Etanol/metabolismo , Fermentación , Saccharomyces cerevisiae/genéticaRESUMEN
PURPOSE: To evaluate the incidence, type and risk factors of cement leakage (CL) with cement-augmented pedicle screw instrumentation (CAPSI) in degenerative lumbosacral disease. METHODS: Two hundred and two patients using a total of 950 cement-augmented screws were enrolled. CL was classified into three types: type S: leakage via segmental veins; type B: leakage via basivertebral veins; and type I: leakage via pedicle screw instrumentation to paravertebral soft tissue. The age, gender, operation stage (primary or later stage), body mass index, bone mineral density, the number and type of augmented screw, the position of the tip of screw (lateral or internal part of vertebral body), the position of screw (left or right side), the volume of bone cement, location of the augmented vertebra (lumbar or sacrum), the type of CL and complications were recorded. Binary logistic regression correlation was used to analyze risk factors of veins leakage (type S and type B). RESULTS: The CL was observed in 165 patients (81.68%) and 335 screws (35.26%), leakage types of S, B and I were seen in 255 (76.12%), 77 (22.99%), and 30 (8.96%) of screws, respectively. Besides, double or multiple routes of leakage were seen in 27 screws. Number of augmented screw was a risk factor for vein leakage (OR 0.58; 95% CI 0.44-0.77; P = 0.000). Furthermore, the doses of cement (OR 0.79; 95% CI 0.61-0.99; P = 0.038) and the position of screw (OR 0.39; 95% CI 0.29-0.53; P = 0.000) were identified as risk factors for type S, and the doses of bone cement (OR 0.37; 95% CI 0.25-0.54; P = 0.000) and the position of the tip of screw (OR 0.07; 95% CI 0.04-0.13; P = 0.000) were risk factors for type B. CONCLUSIONS: CAPSI bears a high risk of asymptomatic CL, with a higher rate of leakage into segmental veins and basivertebral veins. As is known, more augmented screws and larger doses of cement are risk factors for veins leakage (type S and type B), while the tip of screw approaching to the midline of the vertebral body is another risk factor to type B. Thus, the CL could be reduced by the amelioration of operative techniques and procedures. These slides can be retrieved under Electronic Supplementary Material.
Asunto(s)
Cementos para Huesos/efectos adversos , Vértebras Lumbares/cirugía , Tornillos Pediculares , Complicaciones Posoperatorias/etiología , Sacro/cirugía , Enfermedades de la Columna Vertebral/cirugía , Fusión Vertebral/instrumentación , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Fusión Vertebral/efectos adversos , Fusión Vertebral/métodos , Resultado del TratamientoRESUMEN
ß-Amylase is of important biotechnological aid in maltose syrup production. In this study, the extraction condition of ß-amylase from brewer's malt and the optimal dosage of ß-amylase in maltose syrup production were optimized using response surface methodology and uniform design method. The optimal extraction condition of ß-amylase from brewer's malt was composed of 1:17 (g/v) material/liquid ratio, 44°C extraction temperature, pH 6.4 buffer pH, 2.3 H extraction time, and 1.64 g L-1 NaSO3 dosage with a predicted ß-amylase activity of 1,290.99 U g-1 , which was close to the experimental ß-amylase activity of 1,230.22 U g-1 . The optimal dosages of ß-amylase used in maltose syrup production were 455.67 U g-1 starch and its application in maltose syrup production led to a 68.37% maltose content in maltose syrup, which was 11.2% and 28.9% higher than those using ß-amylases from soybean and microbe (P < 0.01). Thus, ß-amylase from brewer's malt was beneficial for production of high maltose syrup.
Asunto(s)
Grano Comestible/metabolismo , Maltosa/biosíntesis , Edulcorantes/metabolismo , beta-Amilasa/aislamiento & purificación , Biotecnología , Fermentación , Concentración de Iones de Hidrógeno , Temperatura , beta-Amilasa/metabolismoRESUMEN
Saccharomyces cerevisiae strains with favorable characteristics are preferred for application in industries. However, the current ability to reprogram a yeast cell on the genome scale is limited due to the complexity of yeast ploids. In this study, a method named genome replication engineering-assisted continuous evolution (GREACE) was proved efficient in engineering S. cerevisiae with different ploids. Through iterative cycles of culture coupled with selection, GREACE could continuously improve the target traits of yeast by accumulating beneficial genetic modification in genome. The application of GREACE greatly improved the tolerance of yeast against acetic acid compared with their parent strain. This method could also be employed to improve yeast aroma profile and the phenotype could be stably inherited to the offspring. Therefore, GREACE method was efficient in S. cerevisiae engineering and it could be further used to evolve yeast with other specific characteristics.
Asunto(s)
Evolución Molecular Dirigida , Ingeniería Genética/métodos , Microbiología Industrial/métodos , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Acetaldehído/química , Ácido Acético/metabolismo , Cerveza , Replicación del ADN , ADN Polimerasa Dirigida por ADN/metabolismo , Fermentación , Microbiología de Alimentos , Variación Genética , Genoma Fúngico , Mutación , Fenotipo , Plásmidos/metabolismoRESUMEN
PURPOSE: Re-collapse of cemented vertebrae occasionally occurs after percutaneous augmentation. However, the potential risks still remain unclear. Several articles have reported some possible risk factors which were not consistent or comprehensive. This study aimed to make a retrospective review on patients with osteoporotic vertebral compression fracture (OVCF) after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) and to further analyse the risk factors for treated vertebral refracture. METHODS: All patients receiving the PKP/PVP with bilateral approach were retrospectively reviewed from January 2014 to January 2016, among whom 230 patients with single level augmentation (30 in refracture group and 200 in the non-refracture group) were enrolled according to inclusion criteria. The following covariates were reviewed: gender, age, height, weight, body mass index (BMI), bone mineral density (BMD), serum bone turnover markers, surgical parameters including approach, cement volume, anterior height, and Cobb angle restoration. Binary logistic regression analysis was used to determine the relative risk of re-collapse of cemented vertebrae. RESULTS: Regarding the patient data, weight, BMI, and BMD were of statistical significance in refracture group (P < 0.01), among which only low BMD was a risk factor to cemented vertebral re-collapse (P = 0.022, OR = 4.197). In respect of surgical variables, the better restoration of anterior height and Cobb angle was found in refracture group (P < 0.05), both of which might increase the refracture risk but not be risk factors (P = 0.065, OR = 0.891, and P = 0.937, OR = 0.996, respectively). Besides, less injected cement (3.30 ± 0.84 ml vs 4.46 ± 1.10 ml, P = 0.000, OR = 19.433) and PKP (P = 0.007, OR = 13.332) significantly boosted the potential risk of refracture (P < 0.001). CONCLUSION: Patients with low BMD, or undergoing PKP, or receiving a low volume of injected cement might have a high risk of re-collapse in surgical vertebrae.
Asunto(s)
Fracturas por Compresión/cirugía , Cifoplastia/efectos adversos , Fracturas Osteoporóticas/cirugía , Fracturas de la Columna Vertebral/cirugía , Vertebroplastia/efectos adversos , Anciano , Anciano de 80 o más Años , Cementos para Huesos/efectos adversos , Densidad Ósea , Femenino , Humanos , Cifoplastia/métodos , Masculino , Persona de Mediana Edad , Recurrencia , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento , Vertebroplastia/métodosRESUMEN
ß-Alanine is an important precursor for the production of food additives, pharmaceuticals, and nitrogen-containing chemicals. Compared with the conventional chemical routes for ß-alanine production, the biocatalytic routes using L-aspartate-α-decarboxylase (ADC) are more attractive when energy and environment are concerned. However, ADC's poorly understood properties and its inherent mechanism-based inactivation significantly limited the application of this enzyme. In this study, three genes encoding the ADC enzymes from Escherichia coli, Corynebacterium glutamicum, and Bacillus subtilis were overexpressed in E. coli. Their properties including specific activity, thermostability, and mechanism-based inactivation were characterized. The ADC enzyme from B. subtilis, which had higher specific activity and thermostability than the others, was selected for further study. In order to improve its activity and relieve its mechanism-based inactivation by molecular engineering so as to improve its catalytic stability, a high-throughput fluorometric assay of ß-alanine was developed. From a library of 4000 mutated enzymes, two variants with 18-22% higher specific activity and 29-64% higher catalytic stability were obtained. The best variant showed 50% higher ß-alanine production than the wild type after 8 h of conversion of L-aspartate, showing great potential for industrial biocatalytic production of ß-alanine.
Asunto(s)
Ingeniería Genética/métodos , Glutamato Descarboxilasa/genética , Glutamato Descarboxilasa/metabolismo , beta-Alanina/biosíntesis , Ácido Aspártico/metabolismo , Bacillus subtilis/enzimología , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Biocatálisis , Corynebacterium glutamicum/enzimología , Corynebacterium glutamicum/genética , Estabilidad de Enzimas , Escherichia coli/enzimología , Escherichia coli/genética , Glutamato Descarboxilasa/biosíntesis , Glutamato Descarboxilasa/química , Ingeniería Metabólica/métodosRESUMEN
INTRODUCTION: The impaired erectile response in spontaneously hypertensive rats (SHR) is caused by increased signaling of RhoA/Rho-kinase and decreased signaling of nitric oxide (NO). Icariin improves erectile function via upregulating multitargets in NO/cyclic guanosine monophosphate (NO/cGMP) pathway, which breviscapine accomplishes by downregulating RhoA/Rho-kinase pathway. AIM: To investigate the effect and mechanism of icariin combined with breviscapine on the erectile function of SHR. METHODS: Five 12-week-old male Wistar-Kyoto (WKY) rats and 20 age-matched male SHR were evenly randomized into WKY rats control group, SHR control group, icariin-treated group, breviscapine-treated group, and combined treatment group treated by vehicle, icariin, breviscapine, and icariin plus breviscapine, respectively, by gavage for four successive weeks. Maximum intracavernosal pressure/mean arterial pressure (ICPmax/MAP) and the expression of endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS), phosphodiesterase type 5 inhibitors (PDE5), and Rho-associated, coiled-coil containing protein kinase 1 and 2 (ROCK1 and ROCK2) in the cavernous tissues were determined. RESULTS: The ICPmax/MAP in the combined treatment group was significantly increased compared with SHR control group, icariin-treated group, and breviscapine-treated group. The expression of eNOS and nNOS was significantly higher in the combined treatment group than in SHR control group, icariin-treated group, and breviscapine-treated group (P < 0.05). The expression of PDE5 was significantly lower in the icariin-treated group than in SHR control group (P < 0.05). The expression of ROCK1 was significantly lower in the combined treatment group than in other groups (P < 0.05). The expression of ROCK2 was significantly higher in SHR control group than in WKY rats control group, icariin-treated group, and combined treatment group (P < 0.05). Among these groups, the expression of eNOS and nNOS was the strongest, and ROCK1 was the lowest in WKY rats control group. CONCLUSION: Icariin combined with breviscapine has synergistic effects on erectile function of SHR through different signal pathways.
Asunto(s)
Medicamentos Herbarios Chinos/administración & dosificación , Flavonoides/administración & dosificación , Erección Peniana/efectos de los fármacos , Animales , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 5/metabolismo , Quimioterapia Combinada , Masculino , Óxido Nítrico Sintasa de Tipo I/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Pene/efectos de los fármacos , Pene/enzimología , Pene/metabolismo , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Quinasas Asociadas a rho/metabolismoRESUMEN
The release and accumulation of perchlorate into the environment have raised concerns about safety to food, however, the dietary risk of perchlorate in honey have not yet received attention. Herein, we investigated the pollution characteristics and assessed the human health risks of perchlorate in honey from China. A total of 151 honey samples collected from 20 provinces of China were analyzed, and overall detection frequencies was 95.4 %. The levels of perchlorate ranged from below limit of quantitation to 612 µg/kg, with a mean value of 34.5 µg/kg. Lychee honey samples had the highest mean perchlorate concentration (163 µg/kg). The mean concentration of perchlorate in the honey samples produced in South China was significantly higher than that in honey from Southwest China, East China and North China (P < 0.05). The health risk assessment showed that mean hazard quotient (HQ) values of different honey for children (ranged from 0.0108 to 0.400) and adults (ranged from 0.0123 to 0.453) were less than 1. This result indicated that mean pollution levels of perchlorate in various honey were unlikely to pose health risk. However, perchlorate concentrations in two lychee honey samples had associated HQ values were >1, suggesting potential health risks. This work not only offers valuable information for honey consumer, but also important reference for comparison of honey samples in the future. ENVIRONMENTAL IMPLICATION: Perchlorate contamination has become a hot environmental issue in connection with human health due to its potential thyroid toxicity and widespread occurrence in environment and foods. Honey not only was widely beloved by consumers worldwide but also considered a potential indicator of environmental pollution. Here, a national investigation and risk assessment of perchlorate levels in different types of honey from China was conducted. The results describe the perchlorate contamination were extensive in honey samples, mean levels of perchlorate in various honey were unlikely to cause health risks. However, significantly high level of contamination in lychee honey should be of concern.
Asunto(s)
Miel , Niño , Adulto , Humanos , Percloratos , Contaminación Ambiental , China , Medición de RiesgoRESUMEN
OBJECTIVE: The floating calcified tissue in floating calcified lumbar disc herniation (FCLDH) is hard and often adheres to the dura mater, which can easily cause nerve root damage during surgery, making the operation challenging. We proposed the classification of FCLDH and a new technique for removing floating calcified tissue and reported the clinical efficacy and safety of this new technique in clinical practice. METHODS: From January 2019 to October 2021, 24 patients (13 males and 11 females, 46.4 ± 7.72 years) with L5-S1 floating calcified lumbar disc herniation were treated with percutaneous endoscopic interlaminar discectomy (PEID). According to FCLDH classification, a total of Type Ia: nine cases, Type Ib: five cases, Type IIa: four cases, and Type IIa: six cases were included. The visual analogue scale (VAS) and Oswestry disability index (ODI) were recorded pre-operatively and 3 days postoperatively, 6 months postoperatively, and at the last follow-up. The postoperative curative effect was evaluated according to the modified MacNab criteria. Computed tomography (CT) and magnetic resonance imaging (MRI) of the lumbar spine were performed 3 days after surgery to evaluate the efficacy of the surgery. RESULTS: All patients successfully underwent PEID. The VAS and ODI scores at 3 days postoperatively, 6 months postoperatively, and at the last follow-up were significantly improved and statistically significant compared to those of the preoperative period (p < 0.05). All the patients were followed up for 12-24 months (mean, 16.6 ± 4.6 months). At the last follow-up, according to the modified MacNab criteria, 15 cases were excellent, eight were good, and one was fair. The combined excellent and good rate was 95.83% (23/24). Postoperative review revealed that all floating calcified tissues were effectively removed and the nerve roots were adequately decompressed without complications such as cerebrospinal fluid leakage and lumbar spine infection. CONCLUSION: The classification of FCLDH we proposed can well guide the selection of surgical plans. PEID combined with floating calcified tissue removal technology has good efficacy in the treatment of L5-S1 FCLDH, ensuring accurate removal of calcified tissue, reducing complications and improving the quality of life of affected individuals.
Asunto(s)
Discectomía Percutánea , Desplazamiento del Disco Intervertebral , Masculino , Femenino , Humanos , Desplazamiento del Disco Intervertebral/cirugía , Vértebras Lumbares/cirugía , Calidad de Vida , Estudios Retrospectivos , Endoscopía/métodos , Discectomía Percutánea/métodos , Discectomía , Resultado del TratamientoRESUMEN
Background: Intervertebral disc degeneration (IDD) is a common musculoskeletal disorder that contributes significantly to disability and healthcare costs. Serum urate concentration has been implicated in the development of various musculoskeletal conditions. While previous observational studies have suggested an association between the two conditions, it might confound the effect of serum urate concentrations on IDD. This Mendelian randomization (MR) study aimed to investigate the causal relationship between serum urate concentration and IDD. Methods: We performed a two-sample MR analysis using summary-level data from genome-wide association studies (GWAS) of serum urate concentration (n = 13 585 994 European ancestry) and IDD (n = 16 380 337 European ancestry). Single nucleotide polymorphisms (SNPs) significantly associated with serum urate concentration (p < 5 × 10-8) were selected as instrumental variables. The associations between genetically predicted serum urate concentration and IDD were estimated using the inverse-variance weighted (IVW) method, with sensitivity analyses employing the weighted median, MR-Egger, and MR-PRESSO approaches to assess the robustness of the findings. Results: In the primary IVW analysis, genetically predicted serum urate concentration was unrelated associated with IDD (odds ratio [OR] = 1.00, 95% confidence interval (CI): 1.00-1.00, p = 0.17)). The results remained consistent across the sensitivity analyses, and no significant directional pleiotropy was detected (MR-Egger intercept: p = 0.15). Conclusions: This MR study provides evidence that there is no causal relationship between serum urate concentration and IDD. It suggests previous observational associations may be confounded. Serum urate levels are unlikely to be an important contributor to IDD.
RESUMEN
Osteoporosis is a systemic disease characterized by an imbalance in bone homeostasis, where osteoblasts fail to fully compensate for the bone resorption induced by osteoclasts. Corylifol A, a flavonoid extracted from Fructus psoraleae, has been identified as a potential treatment for this condition. Predictions from network pharmacology and molecular docking studies suggest that Corylifol A exhibits strong binding affinity with NFATc1, Nrf2, PI3K, and AKT1. Empirical evidence from in vivo experiments indicates that Corylifol A significantly mitigates systemic bone loss induced by ovariectomy by suppressing both the generation and activation of osteoclasts. In vitro studies further showed that Corylifol A inhibited the activation of PI3K-AKT and MAPK pathways and calcium channels induced by RANKL in a time gradient manner, and specifically inhibited the phosphorylation of PI3K, AKT, GSK3 ß, ERK, CaMKII, CaMKIV, and Calmodulin. It also diminishes ROS production through Nrf2 activation, leading to a decrease in the expression of key regulators such as NFATcl, C-Fos, Acp5, Mmp9, and CTSK that are involved in osteoclastogenesis. Notably, our RNA-seq analysis suggests that Corylifol A primarily impacts mitochondrial energy metabolism by suppressing oxidative phosphorylation. Collectively, these findings demonstrate that Corylifol A is a novel inhibitor of osteoclastogenesis, offering potential therapeutic applications for diseases associated with excessive bone resorption.