[Quantification of antigen of Mycoplasma capricolum subsp. capripneumoniae by optical assay]

Mycoplasma capricolum subsp. capripneumoniae (Mccp) is the cause of contagious caprine pleuropneumonia (CCPP) in goats. Inactivated vaccines and capsular polysaccharide (CPS) indirect hemagglutination reagents are available for prevention and serological detection, but high culture costs and complex antigen quantification have been plagued by production staff. In order to solve these problems in production practice, a sugar fermentation medium with an initial pH value of 7.8, which could improve the production of two antigens simultaneously, was screened out by changing the initial pH value based on previous Mccp metabolomics analysis. Since phenol red can be identified by UV absorption spectrum and cetyltrimethylammonium bromide (CTAB) can bind to anionic capsular polysaccharide, a UV spectrum measurement method for analyzing the culture stage reached by Mccp and a CTAB precipitation test for relative quantification of capsular polysaccharide antigen content in the fermentation broth were established. The UV spectrum observation method can guide the production of Mccp according to the growth curve of Mccp, which greatly reduces the monitoring time of the traditional CCU method and improves the accuracy of the original eye-observation method. The established CTAB precipitation test can complete the monitoring of CPS content within 5 hours, which greatly reduces the time required compared with the traditional differential technique, and its accuracy was verified by the phenol-sulfuric acid method. The optimized culture medium and the two correlation comparison methods established in this study can effectively reduce the production cost of Mccp and improve the production efficiency. The two assays have been used in the research at our laboratory, which provides experimental data for further improvement of the production process of CCPP inactivated vaccine and capsular polysaccharide as well as rapid quantification.

Rapid Identification of Different Grades of Huangshan Maofeng Tea Using Ultraviolet Spectrum and Color Difference

Tea is an important beverage in humans’ daily lives. For a long time, tea grade identification relied on sensory evaluation, which requires professional knowledge, so is difficult and troublesome for laypersons. Tea chemical component detection usually involves a series of procedures and multiple steps to obtain the final results. As such, a simple, rapid, and reliable method to judge the quality of tea is needed. Here, we propose a quick method that combines ultraviolet (UV) spectra and color difference to classify tea. The operations are simple and do not involve complex pretreatment. Each method requires only a few seconds for sample detection. In this study, famous Chinese green tea, Huangshan Maofeng, was selected. The traditional detection results of tea chemical components could not be used to directly determine tea grade. Then, digital instrument methods, UV spectrometry and colorimetry, were applied. The principal component analysis (PCA) plots of the single and combined signals of these two instruments showed that samples could be arranged according to grade. The combined signal PCA plot performed better with the sample grade descending in clockwise order. For grade prediction, the random forest (RF) model produced a better effect than the support vector machine (SVM) and the SVM + RF model. In the RF model, the training and testing accuracies of the combined signal were all 1. The grades of all samples were correctly predicted. From the above, the UV spectrum combined with color difference can be used to quickly and accurately classify the grade of Huangshan Maofeng tea. This method considerably increases the convenience of tea grade identification.

Effects of riboflavin and ultraviolet light treatment on pathogen reduction and platelets

BACKGROUND

Pathogen reduction technology has become an accepted method for limiting transfusion-transmitted infections (TTIs). Riboflavin and ultraviolet light (RUV) treatment of platelets (PLTs) is an optional means of pathogen inactivation owing to its safety, effectiveness, and ease of use. However, the literature on effects of ultraviolet (UV) light spectra and doses on pathogen reduction is still contradictory.

METHODS

We tested the effectiveness of killing Escherichia coli following RUV exposure with one broad-spectrum and two narrow-spectrum light sources centered at 311 and 365 nm and at successively higher doses by limited dilution survival assays. After comparing the effectiveness of E coli and phage inactivation (n = 6) and the changes in PLT count and metabolism caused by RUV treatment with optimized UV light at increasing doses, we confirmed our results by using four model virus systems that represent common TTIs, as well as PLT function and activation assays at an optimized light dose.

RESULTS

The narrow-spectrum UV, centered at 311 nm, optimally reduced the E coli titer with a light dose ≥8.11 J/mL, resulting in the same trend of E coli and phage reduction at different light doses. At 8.11 J/mL, 311-nm narrow-spectrum UV had a good inactivation effect on E coli and phages, eliminating many viruses, and resulted in acceptable PLT quality after RUV treatment and during storage for 4 days.

CONCLUSIONS

Our data suggest restricting exposure to narrow-spectrum UV centered at 311 nm can increase E coli elimination and potentially optimize virus titer reduction without significantly compromising PLT quality.

[Control of Coagulant Dosing for Humic Substances Based on Ultraviolet Spectrum Analysis]

Humic substance (HS) is a main component of dissolved organic matter in the aquatic environment and significantly affects water treatment processes. To investigate the applicability and principle of UV spectrum analysis for coagulation control, laboratory jar tests were conducted with synthetic waters that had varying concentrations of HS and kaolinite. Thus, the influence of water quality conditions on the optimal coagulant dose (OCD) was determined and further correlated to Specific Ultraviolet Absorbance (SUVA₂₅₄) and the ultraviolet spectral slopes of the coagulated water. Subsequently, the relationship between the UV spectral slopes and organic fractionation was further identified by using size exclusion chromatography (SEC). The results showed that the coagulant demands of the synthetic waters were positively related to dissolved organic carbon (DOC). Consequently, a stoichiometric relationship (0.61 mg·mg^-1 calculated as Al/DOC) was found between the coagulant demand and initial DOC of the synthetic water. As the coagulant dose increased, SUVA₂₅₄ decreased from 8.9 L·(mg·m)^-1 to a steady level of 2.0 L·(mg·m)^-1 and the removal efficiency of DOC was positively correlated with SUVA₂₅₄. Spectral slopes in different wavelength ranges had showed similar tendencies, with S_275-295 having the best correlation with SUVA₂₅₄ (R²=0.81). Furthermore, SEC results demonstrated that coagulation preferentially removed humic substances, leading to reduced humification. As a result, S_275-295 had the highest correlation with the portion of UVA₂₅₄ contributed by humic substances in water. Therefore, online measurement of ultraviolet spectral slopes was an important aspect in the control of coagulant dosing.