modified-methods-for-loading-high-throughput-dna-extraction-plates

Modified Methods for Loading of High-Throughput DNA Extraction Plates Reduce Potential for Contamination

High-throughput DNA sequencing techniques have contributed substantially to advances in our understanding of relationships among microbial communities, ...

University of Wyoming

As the range of bark beetles expands into new forests and woodlands, the need to understand their effects on multiple trophic levels becomes increasingly important. To date, much attention has been paid to the aboveground processes affected by bark beetle infestation, with a focus on photoautotrophs and ecosystem level processes. However, indirect effects of bark beetle on belowground processes, especially the structure and function of soil microbiota remains largely a black box. Our study examined the impacts of bark beetle-induced tree mortality on soil microbial community structure and function using high-throughput sequencing of the soil bacterial and fungal communities and measurements of extracellular enzyme activities. The results suggest bark beetle infestation affected edaphic conditions through increased soil water content, pH, electrical conductivity, and carbon/nitrogen ratio and altered bulk and rhizosphere soil microbial community structure and function. Finally, increased enzymatic activity suggests heightened microbial decomposition following bark beetle infestation. With this increase in enzymatic activity, nutrients trapped in organic substrates may become accessible to seedlings and potentially alter the trajectory of forest regeneration. Our results indicate the need for incorporation of microbial processes into ecosystem level models. Belowground impacts of bark beetle infestation have not been explored as thoroughly as their aboveground counterparts. In order to accurately model impacts of bark beetle-induced tree mortality on carbon and nutrient cycling and forest regeneration, the intricacies of soil microbial communities must be examined. In this study, we investigated the structure and function of soil bacterial and fungal communities following bark beetle infestation. Our results show bark beetle infestation to impact soil conditions, as well as soil microbial community structure and function.

Structural and Functional Dynamics of Soil Microbes following Spruce Beetle Infestation.

Diet may be a significant determinant of insect gut microbiome composition. However, the extent to which dietary shifts shape both the composition and relevant functions of insect gut microbiomes, and ultimately, impact host energy balance (i.e., metabolic phenotype) is not well understood. We investigated the impacts of diet switching on  females maintained on dog food (DF) diet relative to those fed a comparatively sub-optimal cellulose-amended dog food (CADF) diet for four weeks. After this period, dietary shift resulted in a significantly higher average mass-specific standard metabolic rate (SMR) in CADF-fed females compared to DF-fed females. We also uncovered significant C-enrichment in DF-fed insect samples relative to CADF-fed insect samples and lowered bacterial essential amino acid (EAA) provisioning in CADF-fed samples. Differences in SMR and EAA provisioning were not accompanied by significant differences in overall microbiome composition between the two groups. However, cellulolytic and nitrogen-fixing bacterial families dominant in wild omnivorous cockroaches and wood-feeding termites were significantly enriched in CADF-fed females than in DF-fed females, at the end of the study. We propose that these changes in microbiome composition after dietary shifts are associated with changes in EAA provisioning and possibly SMR. Further studies are needed to comprehensively understand the relative importance of gut microbial functions among the complexity of factors known to underscore SMR responses in insects under varying dietary conditions.

Article	Year
Structural and Functional Dynamics of Soil Microbes following Spruce Beetle Infestation. Applied and environmental microbiology\| PubMed ID: 31732575	2020
The role of the gut microbiome in mediating standard metabolic rate after dietary shifts in the viviparous cockroach, . The Journal of experimental biology\| PubMed ID: 32393544	2020

Gordon F. Custer

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