Glomalin-related soil protein: Assessment of current detection and quantification tools

Despite the widely acknowledged importance of arbuscular mycorrhizal fungi (AMF) in soil ecology, quantifying their biomass and presence in field soils is hindered by tedious techniques. Hence biochemical markers may be useful, among which glomalin-related soil protein (GRSP) could show a particular promise. Presently GRSP is operationally defined, its identification resting solely on the methods used to extract it from soil (citric acid buffer and autoclaving) and the assays (Bradford/enzyme-linked immunosorbent assay (ELISA) with a monoclonal antibody) utilized to detect it. The current assumption is that most non-heat stable soil proteins except glomalin are destroyed during the harsh extraction procedure. However, this critical assumption has not been tested. The purpose of this research was to challenge the GRSP extraction process to determine the accuracy of the Bradford method as a measure of glomalin; and to provide some assessment of the specificity of the ELISA monoclonal antibody. In two studies we spiked soil samples either with known quantities of a glycoprotein (BSA: bovine serum albumin) or with leaf litter from specific sources. After extraction 41-84% of the added BSA was detected with the Bradford method. This suggests that the currently used extraction procedure does not eliminate all non-glomalin proteins. Also, ELISA cross-reactivity against BSA was limited, ranging from 3% to 14%. Additions of leaf litter also significantly influenced GRSP extraction and quantification suggesting that plant-derived proteins, as would occur in the field, had a similar effect as BSA. Litter additions decreased the immunoreactive protein values, suggesting interference with antibody recognition. We conclude that the use of GRSP, especially Bradford-based detection, in the assessment of AMF-derived substances within field soils is problematic, it may be inappropriate in situations of significant organic matter additions.     

基于布拉德福定律的海洋学科学术论文分布研究

本文以布拉德福定律为理论基础,以CNKI中的“中国期刊全文数据库”作为数据的统计源,对海洋学科的学术论文的分布进行研究,得知在数据库环境下该学科的期刊论文布基本符合布拉福德定律;同时利用该方法确定数据库中有关海洋学科的核心期刊,并将其与中文核心期刊要目总览进行对比分析。     

对布拉德福定律合理性的思考

学科复杂化发展趋势给布拉德福定律适用范围带来挑战,通过总结近年来对布拉德福定律本身及其合理性的一些研究,定性地分析说明布拉德福定律值得商榷,并提出布拉德福定律作为一个＂经验定律＂在实际研究与应用中应注意的问题,以期为今后对布拉德福定律乃至其他科学经验定律的研究与应用提供参考。