Project description:Analysis of microbial community composition in arctic tundra and boreal forest soils using serial analysis of ribosomal sequence tags (SARST). Keywords: other
Project description:Accurate description of a microbial community is an important first step in understanding the role of its components in ecosystem function. A method for surveying microbial communities termed Serial Analysis of Ribosomal DNA (SARD) is described here. Through a series of molecular cloning steps, short DNA sequence tags are recovered from the fifth variable (V5) region of the prokaryotic 16S rRNA gene from microbial communities. These tags are ligated to form concatemers comprised of 20-40 tags which are cloned and identified by DNA sequencing. Four agricultural soil samples were profiled with SARD to assess the method’s utility. A total of 37,008 SARD tags comprising 3,127 unique sequences were identified. Comparison of duplicate profiles from one soil genomic DNA preparation revealed the method was highly reproducible. The large numbers of singleton tags together with non-parametric richness estimates indicated a significant amount of sequence tag diversity remained undetected with this level of sampling. The abundance classes of the observed tags were scale-free and conformed to a power law distribution. Numerically, the majority of the total tags observed belonged to abundance classes that were each present at less than 1% of the community. Over 99% of the unique tags individually made up less than 1% of the community. Therefore, from either numerical or diversity standpoints, low abundant taxa comprised a significant proportion of the microbial communities examined and could potentially make a large contribution to ecosystem function. SARD may provide a means to explore the ecological role of these rare members of microbial communities in qualitative and quantitative terms. Keywords: SARD profiles, culture-independent study, microbial community survey, microbial census
Project description:Honey promotes health and is an effective non-pharmacological home remedy against common respiratory infections. However, industrial processing and manipulation of raw honey can have a detrimental effect on its biological activities, including antibacterial ones, and hence its health-benefiting qualities. Therefore, this study aimed to compare the honey’s antibacterial activity, its total protein content, and the abundance of the most dominant bee-derived proteins in honey between raw (n=92) and supermarket (n=17) samples. We showed that raw honey samples were much more effective in inhibiting the growth of Staphylococcus aureus with a median minimal inhibitory concentration (MIC) value of 4.5% compared to supermarket honey samples ceasing bacterial growth with a median MIC value of 36%. Moreover, raw honey samples contained significantly higher amounts of total protein as well as the content of particular bee-derived proteins (major royal jelly protein 1 (MRJP1), glucose oxidase (GOX), and α-glucosidase) in contrast to supermarket honey samples. These data hint that some marketed honey samples could be deliberately manipulated with syrup, especially those that exhibited low protein content. In addition, the supermarket honey sample with the lowest protein content contained α-amylase (diastase) from Aspergillus oryzae. Strikingly, the content of this foreign enzyme in honey was roughly 60 times higher than the naturally occurring bee α-amylase. Our findings highlight the burning need to refine and monitor the specific quality parameters, ensuring the authenticity of honey and maintaining its reputation as a functional food.
Project description:This is the first metaproteomics-based featuring of the microbial community harbured in the traditional raw milk Caprino Nicastrese cheese