Biology subjects

Seeber, J.

Publications and source records attributed to Seeber, J..

2 recordsLinked to original sources

bioRxiv2022

Comparison of microbial communities from diverse biological matrices using mock community as an in situ positive control

Metataxonomy has become the standard for characterizing the diversity and composition of microbial communities associated with multicellular organisms and their environment. Understanding the interactions between the microbiotas within the same ecosystem is essential for fully understanding the role of microorganisms in evolutionary and ecological processes; however, such comparative studies across diverse biological samples are rare. In particular, currently available protocols assume a uniform DNA extraction, amplification and sequencing efficiency for all sample types and taxa. The addition of a mock community (MC) to biological samples before the DNA extraction step could aid identification of technical biases, but the impact of MC on diversity estimates is unknown. Here, standardized aliquots of bovine faecal samples with high or low biomass were extracted with high or low doses of MC, characterized using standard Illumina technology for metataxonomics, and analysed with custom bioinformatic pipelines. We showed that a MC was an informative in situ positive control provided an estimate of 16S rRNA sample gene copies (which allowed a more direct measure of community size), and detected sample outliers. However, we also demonstrated that if the recommended dose of MC is added to a sample with low biomass, diversity estimates were distorted. Using our results, we recommend MC doses for a range of sample types, including rhizosphere soil, whole invertebrates, and vertebrate faecal samples. ImportanceThe simultaneous processing of the sample microbiota with a known number of readily identifiable MC cells (co-extracted with the sample cells) or SNA (co-amplified with the sample DNAs) can be a valuable in situ positive control. However, guidelines regarding their application are very limited and do not consider the effect of these controls on sample diversity estimates. We demonstrate that a MC co-extracted with the study sample provides several advantages, such as highlighting bias in DNA extraction of gram positive, identifying potential sample outliers and inferring the number of 16S rRNA gene copies in the sample. However, the incorporation of a MC requires prior knowledge of sample biomass, as high ratios of MC to sample microbiota lead to biased sample diversity estimates. Practical advice on determining the appropriate MC dose for a wide range of sample types, including rhizosphere soil, whole invertebrates and mammalian faecal samples are provided.

ecology↗

bioRxiv2022

Global monitoring of soil animal communities using a common methodology

Here we introduce the Soil BON Foodweb Team, a cross-continental collaborative network that aims to monitor soil animal communities and food webs using consistent methodology at a global scale. Soil animals support vital soil processes via soil structure modification, direct consumption of dead organic matter, and interactions with microbial and plant communities. Soil animal effects on ecosystem functions have been demonstrated by correlative analyses as well as in laboratory and field experiments, but these studies typically focus on selected animal groups or species at one or few sites with limited variation in environmental conditions. The lack of comprehensive harmonised large-scale soil animal community data including microfauna, mesofauna, and macrofauna, in conjunction with related soil functions, limits our understanding of biological interactions in soil communities and how these interactions affect ecosystem functioning. To provide such data, the Soil BON Foodweb Team invites researchers worldwide to use a common methodology to address six long-term goals: (1) to collect globally representative harmonised data on soil micro-, meso-, and macrofauna communities; (2) to describe key environmental drivers of soil animal communities and food webs; (3) to assess the efficiency of conservation approaches for the protection of soil animal communities; (4) to describe soil food webs and their association with soil functioning globally; (5) to establish a global research network for soil biodiversity monitoring and collaborative projects in related topics; (6) to reinforce local collaboration networks and expertise and support capacity building for soil animal research around the world. In this paper, we describe the vision of the global research network and the common sampling protocol to assess soil animal communities and advocate for the use of standard methodologies across observational and experimental soil animal studies. We will use this protocol to conduct soil animal assessments and reconstruct soil food webs on the sites included in the global soil biodiversity monitoring network, Soil BON, allowing us to assess linkages among soil biodiversity, vegetation, soil physico-chemical properties, and ecosystem functions. In the present paper, we call for researchers especially from countries and ecoregions that remain underrepresented in the majority of soil biodiversity assessments to join us. Together we will be able to provide science-based evidence to support soil biodiversity conservation and functioning of terrestrial ecosystems.

ecology↗