RESUMEN
OBJECTIVE: We created a novel, high sensitivity immunochromatographic assay that allows for clear and precise quantitative analysis by employing innovative bimetallic nanoparticles with peroxide-like activity as markers for the preparation of the test strip. METHODS: Initially, we synthesized Pt-Pd bimetallic nanoparticles through the reduction of K2PtCl4 and Na2PdCl4 using ascorbic acid (AA) in an ultrasonic water bath. These bimetallic nanoparticles were then utilized to label purified antigens from the foot-and-mouth disease virus (FMDV) type O (FMDV-146S), resulting in the creation of antigen-captured nanomarkers. Upon completion of the antigen-antibody reaction, we introduced a color-developing agent (3,3',5,5'-tetramethylbenzidine) for cascade amplification, significantly enhancing detection sensitivity while ensuring clear and accurate quantitative analysis. RESULTS: The quantitative detection sensitivity achieved was 1:28/test, with a linear range spanning from 1:26 â¼ 1:29 /test. For FMDV type O positive serum, the detection sensitivity reached 96.7 %. Furthermore, this method exhibited a 95 % detection sensitivity for FMDV negative serum, FMDV type A and type Asiaâ positive sera, as well as sera positive for other common viral diseases in animals. In comparison to the OIE-recommended LPB-ELISA, this approach displayed higher correlation (correlation coefficient = 0.909). Innovation was at the core of establishing this immunochromatographic assay based on Pt-Pd bimetallic nanoparticles for the detection of FMDV antibodies. CONCLUSION: The findings revealed a striking 24-fold improvement in sensitivity when compared to colloidal gold, accompanied by a strong correlation coefficient (R2 > 0.9). This suggests a robust and consistent linear association in the results. This method represents a significant advancement in the field of rapid immunochromatographic assays, offering a promising alternative application for bimetallic nanoparticles.
Asunto(s)
Virus de la Fiebre Aftosa , Fiebre Aftosa , Animales , Fiebre Aftosa/diagnóstico , Serogrupo , Inmunoensayo/métodos , Ensayo de Inmunoadsorción Enzimática/métodos , Sensibilidad y EspecificidadRESUMEN
The purpose of study was to investigate the in vitro proliferation ability of PHA-induced CIK cells and traditionally prepared CIK cells, the effector cell level and its influence on killing activity to K562 cells, and to analyze the difference between them. The peripheral blood mononuclear cells(PBMNC) of healthy persons were isolated and divided into A and B group. The CIK cells in A group were obtained by using traditional culture method, the CIK cells in B group were prepared by PHA induction. During the cultivation, the cell survival rate and cell absolute value in the cell culture system were counted every 3 days. On day 15 of culture, the cell immunophenotype of 2 groups were detected by flow cytometry, and the ratios of CD3(+)CD56(+), CD3(+)CD8(+) and CD3(+)CD4(+) cells in total cell amount of culture system were accounted. Meantime, the killing activity to K562 cells in different effector-target ratios was detected by using CCK-8 kit between the 2 groups. The results showed that the method of preparing CIK by PHA induction promoted the cell proliferation more than that of the traditional method (P < 0.05), moreover, both the survival rate of cells in 2 groups was more than 90%. The CD3(+)CD8(+), CD3(+)CD56(+) cell ratio in 2 groups obviously increased. As compared with traditional method, the CD3(+)CD8(+) cell level in B group was enhanced (P < 0.05); but there were no statistical differences in increase of CD3(+)CD56(+) cell level and decrease of CD3(+)CD4(+) cell level between 2 groups. while the effector-target ratio is 5:1, 10:1, 20:1 and 40:1, the killing activity of PHA-induced CIK cells to K562 cells was more stronger than traditionally-prepared CIK cells (P < 0.05), moreover, along with increase of effector-target ratio, the difference of killing activity to K562 cells in 2 groups significantly increased. It is concluded that compared with traditional method for preparing CIK cells, the new way by PHA induction can increase the proliferation of CIK cells obviously, enhance the ratio of CD3(+)CD8(+) cells and strengthen the killing activity to the K562 cells. This new way provides a new source of CIK cells and reliable evidence for cyto-immune therapy of leukemia and other tumors.
Asunto(s)
Células Asesinas Inducidas por Citocinas/citología , Fitohemaglutininas/farmacología , Proliferación Celular , Humanos , Células K562 , Leucocitos MononuclearesRESUMEN
BACKGROUND: Phenyllactic acid (PLA), a novel antimicrobial compound with broad and effective antimicrobial activity against both bacteria and fungi, can be produced by many microorganisms, especially lactic acid bacteria. However, the concentration and productivity of PLA have been low in previous studies. The enzymes responsible for conversion of phenylpyruvic acid (PPA) into PLA are equivocal. METHODOLOGY/PRINCIPAL FINDINGS: A novel thermophilic strain, Bacillus coagulans SDM, was isolated for production of PLA. When the solubility and dissolution rate of PPA were enhanced at a high temperature, whole cells of B. coagulans SDM could effectively convert PPA into PLA at a high concentration (37.3 g l(-1)) and high productivity (2.3 g l(-1) h(-1)) under optimal conditions. Enzyme activity staining and kinetic studies identified NAD-dependent lactate dehydrogenases as the key enzymes that reduced PPA to PLA. CONCLUSIONS/SIGNIFICANCE: Taking advantage of the thermophilic character of B. coagulans SDM, a high yield and productivity of PLA were obtained. The enzymes involved in PLA production were identified and characterized, which makes possible the rational design and construction of microorganisms suitable for PLA production with metabolic engineering.
Asunto(s)
Bacillus/metabolismo , Ácido Láctico/metabolismo , Ácidos Fenilpirúvicos/metabolismo , Bacillus/enzimología , Calor , Cinética , L-Lactato Deshidrogenasa/metabolismo , NAD/metabolismo , Especificidad por SustratoRESUMEN
Highly efficient D-lactate production by Sporolactobacillus sp. strain CASD was demonstrated in this study. Peanut meal was found to be a better nutrient than yeast extract, soybean meal, soybean peptone, corn steep, liquor beef extract, and ammonium sulfate in the production of D-lactate. To improve the utilization of peanut meal, the material was enzymatically hydrolyzed and simultaneously utilized as the nitrogen source in D-lactate fermentation. Very high D-lactate production (207 g/L) was obtained using 40 g/L of peanut meal in 30-L fed-batch fermentation, with the average productivity of 3.8 g/(L·h) and optical purity of 99.3%. The production of such a high concentration of optically pure D-lactate by strain CASD, with the simultaneous enzymatic hydrolysis of peanut meal and fermentation, represents a new cost-efficient and integrated method for D-lactate production using agricultural by-products.
Asunto(s)
Arachis/metabolismo , Bacillales/enzimología , Bacillales/metabolismo , Ácido Láctico/metabolismo , Enzimas/metabolismo , Fermentación , Hidrólisis , Nitrógeno/metabolismoRESUMEN
D-lactic acid was produced by Sporolactobacillus sp. strain CASD in repeated batch fermentation with one- and two-reactor systems. The strain showed relatively high energy consumption in its growth-related metabolism in comparison with other lactic acid producers. When the fermentation was repeated with 10% (v/v) of previous culture to start a new batch, D-lactic acid production shifted from being cell-maintenance-dependent to cell-growth-dependent. In comparison with the one-reactor system, D-lactic acid production increased approximately 9% in the fourth batch of the two-reactor system. Strain CASD is an efficient D-lactic acid producer with increased growth rate at the early stage of repeated cycles, which explains the strain's physiological adaptation to repeated batch culture and improved performance in the two-reactor fermentation system. From a kinetic point of view, two-reactor fermentation system was shown to be an alternative for conventional one-reactor repeated batch operation.