Soil Microbial Community Dynamics during the Decomposition Period of Winter Cover Crops

Across the Midwest United States, there is an increasing number of agriculturalists incorporating cover crops and reduced tillage residue management into sustainable nutrient management plans. However, the impact of these treatments on the soil microbial community, and subsequently, on soil nutrient cycling and inorganic nitrogen (N) availability, is largely unknown. Therefore, this research had two objectives: i) to determine the impact of cover crop species on soil and litter enzyme activity and soil nitrogen supply during the cover crop decomposition period, and ii) to evaluate the impact of cover crops and reduced tillage on the soil microbial community diversity and composition during the cover crop decomposition period. Enzyme activity was measured through β-glucosidase and urease activity assessments on soil and cover crop litter. Soil microbial communities were characterized using the small subunit (16S) rRNA gene sequences determined using the Illumina MiSeq system and analyzed with the QIIME bioinformatics pipeline. Results indicate that cover crops and tillage treatment significantly influenced soil and litter enzyme activity and inorganic N availability during the decomposition period. Specifically, soil β-glucosidase activity peaked in all cover crop treatments in 2016 and 2017 within six decomposition degree-days (DCDs) following cover crop termination. Both seasons, peak inorganic N availability occurred within seven DCDs from peak β-glucosidase activity. In addition, this study revealed that the structure of the soil microbiome changed during the decomposition period. This was evident through changes in microbial community ɑ- and β-diversity, and these differences were greater as the decomposition period progressed, most notably after DCD 2.9 when a majority of the cover crop decomposition occurred. Residue management treatment was also a significant determinant of the soil microbial community structure, and the impact of these treatments was greatest at DCD 6.4. The variation of the soil microbiome structure at the beginning and end of the decomposition period was greater than the variation during peak cover crop decomposition. Overall, it was concluded that DCD, cover crop treatment, and residue management treatment were important variables in explaining the variance of the genus level observations. This study increases our understanding of how the soil microbial community responds to carbon inputs during the decomposition of winter cover crops, leading to the identification of bacteria that are highly responsive to management practices during the cash crop growing season and having the largest effect in differentiating cover crop species. Understanding the abundance patterns of the microbiota that are influenced by management practices has the potential to help optimize agriculture management practices to promote beneficial microorganisms as the adoption of management practices such as cover cropping and reduced tillage residue management treatments continues

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Comparative genomics of the genus Roseburia reveals divergent biosynthetic pathways that may influence colonic competition among species

Roseburia species are important denizens of the human gut microbiome that ferment complex polysaccharides to butyrate as a terminal fermentation product, which influences human physiology and serves as an energy source for colonocytes. Previous comparative genomics analyses of the genus Roseburia have examined polysaccharide degradation genes. Here, we characterize the core and pangenomes of the genus Roseburia with respect to central carbon and energy metabolism, as well as biosynthesis of amino acids and B vitamins using orthology-based methods, uncovering significant differences among species in their biosynthetic capacities. Variation in gene content among Roseburia species and strains was most significant for cofactor biosynthesis. Unlike all other species of Roseburia that we analysed, Roseburia inulinivorans strains lacked biosynthetic genes for riboflavin or pantothenate but possessed folate biosynthesis genes. Differences in gene content for B vitamin synthesis were matched with differences in putative salvage and synthesis strategies among species. For example, we observed extended biotin salvage capabilities in R. intestinalis strains, which further suggest that B vitamin acquisition strategies may impact fitness in the gut ecosystem. As differences in the functional potential to synthesize components of biomass (e.g. amino acids, vitamins) can drive interspecies interactions, variation in auxotrophies of the Roseburia spp. genomes may influence in vivo gut ecology. This study serves to advance our understanding of the potential metabolic interactions that influence the ecology of Roseburia spp. and, ultimately, may provide a basis for rational strategies to manipulate the abundances of these species

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic