Analysis of differential strategies to enhance detection of low‐abundance proteins in the bovine serum proteome

Serum‐based biomarkers hold propitious applications for addressing livestock health, and management. However, discovery of protein biomarkers in complex biological fluids like serum is wholly intractable due to the large dynamic range of protein concentrations; that is, ?10–12 high abundance proteins constitute >90% of the total protein content and effectively mask proteomic detection of low‐abundance biomarkers. Toward addressing this limitation, we test a continuous elution size‐based fractionation method, and two approaches that use affinity interaction‐based separation of proteins in preparing bovine serum, and compare liquid chromatography tandem mass spectrometry protein identification to neat serum. Our results identify the high‐abundance proteins in bovine serum, and demonstrate dynamic range compression and improved protein identification with the different enrichment methods. Although these findings indicate the highest protein number identified in bovine serum (445 proteins, all methods combined), and by any single sample processing method (312 proteins) to date, they still remain lower than levels deemed necessary for biomarker discovery. As such, this investigation revealed limitations to resolving the bovine serum proteome, and the need for species‐specific tools for immunodepleting high‐abundance proteins. In concert, this study represents a step toward advancing sample preparation methods for bovine serum biomarker identification.     

microRNAs作为结核分枝杆菌感染标志物的研究进展

微小RNA(microRN.As)是一类长度约为22个核苷酸的非编码单链RNA分子,它参与基因转录后的表达调控,在免疫系统的调控和运行中具有重要作用。结核分枝杆菌是典型的胞内寄生菌,其感染能够引起人畜共患结核病。从microRNAs与结核免疫机制的相关性以及在结核分枝杆菌感染过程中巨噬细胞、外周血单核细胞及血清中microRNAs表达谱变化等方面,进行综述microRNAs作为结核分枝杆菌感染标志物的研究现状,以期为动物结核病检测提供理论参考。     

Study of cadmium (Cd)-induced oxidative stress in Eisenia fetida based on mathematical modelling

As a sensitive biological indicator, earthworms are widely used to monitor various pollutants of soil and provide an early warning for soil pollution. However, because many indices are involved in the exposure-induced oxidative stress response, practical applications of these indices are quite inconvenient. Therefore, it is appropriate to investigate the key monitoring index for use in early warning and pollution monitoring. Using Eisenia fetida as an experimental model in an indoor simulation experiment, the mathematical modelling of the effect on oxidative stress in earthworms under cadmium (Cd) stress was studied. The test lasted 40 d, with the removal of one earthworm every 10 d. The Cd²⁺ concentration gradient was set as 0, 1, 10, 20, 100, 200, 400, and 800 mg kg^-1 dry weight. The earthworms were divided into two sections from the clitellum for the determination of total protein (TP) and peroxidase (POD), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GPX), catalase (CAT), malondialdehyde (MDA), and acetylcholinesterase (AChE) activities. Results showed that POD was the key index of oxidative stress in head tissues after 10 d of exposure, TP was the key index at 20 d, and POD became the key index again at 30 and 40 d. By contrast, in tail tissues, MDA and SOD were the key indices at an exposure time of 10 d, GPX at 20 d, CAT and TP at 30 d, and POD and MDA at 40 d. These results contribute to establishing a scientific method for ecotoxicological diagnosis and revealing the mechanism of soil Cd toxicity.     

Effect of drying treatment on the respiratory quinone profile in soil

Recently, the analysis of the microbial community structure in soil has received a great deal of attention. Various analytical methods based on biomarkers have been developed: 16S-rDNA, total DNA, phospholipid fatty acids, ergosterols, muramic acids, etc. (Tunlid and White 1992; Carter and Lynch 1993). In a previous paper, we reported that respiratory quinones are useful biomarkers to characterize the microbial community structure in soil (Fujie et al. 1998). In these analyses, only fresh moist soils or frozen soils had been used as samples. However, the soil samples are generally stored in the dark after air drying in many research institutes and experimental stations. It was considered that the analysis of microbial communities in dried soil samples was not possible.

In this paper, we observed that the drying of soils did not affect the proportions of quinone species in soil although the treatment decreased the amount of extracted quinones. These findings suggest that the analysis of the respiratory quinone profile of dried soils reflects the micro biota present in fresh moist soils before drying.     

PFOA对土壤酶活性的影响

Perfluorooctanoic acid (PFOA) is a popular additive of the chemical industry; its effect on activities of important soil enzymes is not well understood. A laboratory incubation experiment was carried out to analyze the PFOA-induced changes in soil urease, catalase, and phosphatase activities. During the entire incubation period, the activities of the three soil enzymes generally declined with increasing PFOA concentration, following certain dose-response relationships. The values of EC 10 , the contaminant concentration at which the biological activity is inhibited by 10%, of PFOA for the soil enzyme activity calculated from the modeling equation of the respective dose-response curve suggested a sensitivity order of phosphatase > catalase > urease. The effect of PFOA on soil enzyme activities provided a basic understanding of the eco-toxicological effect of PFOA in the environment. Results of this study supported using soil phosphatase as a convenient biomarker for ecological risk assessment of PFOA-polluted soils.     

土壤微生物群落对高剂量的新鲜橄榄油厂废水的响应

An incubation experiment was designed in order to determine the further microbiological response to an addition (500 m³ ha^-1) of fresh olive mill wastewater (FOMWW) in a soil that has been frequently amended with uncontrolled doses of OMWW since 90s in an active disposal site (ADS soil). To achieve this aim, the phospholipid fatty acid (PLFA) profiles, microbial biomass C (C_mic), and dehydrogenase (DHA) and urease activities (URA) were monitored at the beginning (T₀), 3 h (T₁) and 97 d (T_f, i.e., the end) of incubation after FOMWW addition. After the FOMWW addition, an increase in the ratio of fungal to bacterial PLFAs was observed in ADS soil. Moreover, a relative increase of monounsaturated fatty acids (MUFAs) with respect to saturated fatty acids (SATFA) was found in the ADS soil. An increase of the Gram-positive to Gram-negative ratio was observed in this soil at the end of the incubation. While DHA and Cmic increased in the ADS soil after FOMWW addition, URA showed a decrease. Fungi and Gram-positive bacterial biomass experienced an increase after addition of a high dose of FOMWW in laboratory conditions.