Identification of 2,4-diacetylphloroglucinol production in the genus Chromobacterium.

The compound 2,4-diacetylphloroglucinol (DAPG) is a broad-spectrum antibiotic that is primarily produced by Pseudomonas spp. DAPG plays an important role in the biocontrol disease suppressing activity of Pseudomonas spp. In the current study, we report the discovery of the DAPG biosynthetic cluster in strains of Chromobacterium vaccinii isolated from Brazilian aquatic environments and the distribution of the biosynthetic cluster in the Chromobacterium genus. Phylogenetic analysis of the phlD protein suggests the biosynthetic cluster probably entered the genus of Chromobacterium after a horizontal gene transfer event with a member of the Pseudomonas fluorescens group. We were able to detect trace amounts of DAPG in wild type cultures and confirm the function of the cluster with heterologous expression in Escherichia coli. In addition, we identified and verified the presence of other secondary metabolites in these strains. We also confirmed the ability of C. vaccinii strains to produce bioactive pigment violacein and bioactive cyclic depsipeptide FR900359. Both compounds have been reported to have antimicrobial and insecticidal activities. These compounds suggest strains of C. vaccinii should be further explored for their potential as biocontrol agents.

Reduction in Long-term Mortality After Sleeve Gastrectomy and Gastric Bypass Compared to Nonsurgical Patients With Severe Obesity.

OBJECTIVE: To separately compare the long-term risk of mortality among bariatric surgical patients undergoing either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) to large, matched, population-based cohorts of patients with severe obesity who did not undergo surgery. BACKGROUND: Bariatric surgery has been associated with reduced long-term mortality compared to usual care for severe obesity which is particularly relevant in the COVID-19 era. Most prior studies involved the RYGB operation and there is less long-term data on the SG. METHODS: In this retrospective, matched cohort study, patients with a body mass index ≥35 kg/m 2 who underwent bariatric surgery from January 2005 to September 2015 in three integrated health systems in the United States were matched to nonsurgical patients on site, age, sex, body mass index, diabetes status, insulin use, race/ethnicity, combined Charlson/Elixhauser comorbidity score, and prior health care utilization, with follow-up through September 2015. Each procedure (RYGB, SG) was compared to its own control group and the two surgical procedures were not directly compared to each other. Multivariable-adjusted Cox regression analysis investigated time to all-cause mortality (primary outcome) comparing each of the bariatric procedures to usual care. Secondary outcomes separately examined the incidence of cardiovascular-related death, cancer related-death, and diabetes related-death. RESULTS: Among 13,900 SG, 17,258 RYGB, and 87,965 nonsurgical patients, the 5-year follow-up rate was 70.9%, 72.0%, and 64.5%, respectively. RYGB and SG were each associated with a significantly lower risk of all-cause mortality compared to nonsurgical patients at 5-years of follow-up (RYGB: HR = 0.43; 95% CI: 0.35,0.54; SG: HR = 0.28; 95% CI: 0.13,0.57) Similarly, RYGB was associated with a significantly lower 5-year risk of cardiovascular-(HR = 0.27; 95% CI: 0.20, 0.37), cancer- (HR = 0.54; 95% CI: 0.39, 0.76), and diabetes-related mortality (HR = 0.23; 95% CI:0.15, 0.36). There was not enough follow-up time to assess 5-year cause-specific mortality in SG patients, but at 3-years follow-up, there was significantly lower risk of cardiovascular- (HR = 0.33; 95% CI:0.19, 0.58), cancer- (HR = 0.26; 95% CI:0.11, 0.59), and diabetes-related (HR = 0.15; 95% CI:0.04, 0.53) mortality for SG patients. CONCLUSION: This study confirms and extends prior findings of an association with better survival following bariatric surgery in RYGB patients compared to controls and separately demonstrates that the SG operation also appears to be associated with lower mortality compared to matched control patients with severe obesity that received usual care. These results help to inform the tradeoffs between long-term benefits and risks of bariatric surgery.

Trans-ancestral fine-mapping of MHC reveals key amino acids associated with spontaneous clearance of hepatitis C in HLA-DQß1.

Spontaneous clearance of acute hepatitis C virus (HCV) infection is associated with single nucleotide polymorphisms (SNPs) on the MHC class II. We fine-mapped the MHC region in European (n = 1,600; 594 HCV clearance/1,006 HCV persistence) and African (n = 1,869; 340 HCV clearance/1,529 HCV persistence) ancestry individuals and evaluated HCV peptide binding affinity of classical alleles. In both populations, HLA-DQß1Leu26 (p valueMeta = 1.24 × 10-14) located in pocket 4 was negatively associated with HCV spontaneous clearance and HLA-DQß1Pro55 (p valueMeta = 8.23 × 10-11) located in the peptide binding region was positively associated, independently of HLA-DQß1Leu26. These two amino acids are not in linkage disequilibrium (r2 < 0.1) and explain the SNPs and classical allele associations represented by rs2647011, rs9274711, HLA-DQB1∗03:01, and HLA-DRB1∗01:01. Additionally, HCV persistence classical alleles tagged by HLA-DQß1Leu26 had fewer HCV binding epitopes and lower predicted binding affinities compared to clearance alleles (geometric mean of combined IC50 nM of persistence versus clearance; 2,321 nM versus 761.7 nM, p value = 1.35 × 10-38). In summary, MHC class II fine-mapping revealed key amino acids in HLA-DQß1 explaining allelic and SNP associations with HCV outcomes. This mechanistic advance in understanding of natural recovery and immunogenetics of HCV might set the stage for much needed enhancement and design of vaccine to promote spontaneous clearance of HCV infection.

Atmospheric Occurrence of Legacy Pesticides, Current Use Pesticides, and Flame Retardants in and around Protected Areas in Costa Rica and Uganda.

Protected areas have developed alongside intensive changes in land use and human settlements in the neighboring landscape. Here, we investigated the occurrence of 21 organochlorine pesticides (OCPs), 14 current use pesticides (CUPs), 47 halogenated flame retardants (HFRs), and 19 organophosphate esters (OPEs) in air around Las Cruces (LC) and La Selva (LS) Biological Stations, Costa Rica, and Kibale National Park (KNP), Uganda using passive air samplers (PAS) with polyurethane foam (PUF) discs (PAS-PUF). Significantly higher concentrations of CUPs were observed around LS, while LC had a higher concentration of OCPs. Land use analysis indicated that LS had a higher fraction of agriculture than LC (33% vs 14%), suggesting the higher CUPs concentration at LS was related to pesticide intensive crops, while higher OCPs concentration at LC may be attributed to the area's long agricultural history characterized by small-scale subsistence farming or long-range transport. In Uganda, CUPs and OCPs were generally lower than in Costa Rica, but high concentrations of HFRs were observed inside KNP, possibly due to human activity at research camps near the protected forest. This is the first study that documented the occurrence of anthropogenic chemicals in the air at protected areas with tropical forests.

Using hyper as a molecular probe to visualize hydrogen peroxide in living plant cells: a method with virtually unlimited potential in plant biology.

Reactive oxygen species (ROS) are highly reactive reduced oxygen molecules that play a myriad of roles in animal and plant cells. In plant cells, the production of ROS occurs as a result of aerobic metabolism during respiration and photosynthesis. Therefore mitochondria, chloroplasts, and peroxisomes constitute an important source of ROS. However, they can be produced in response to many physiological stimuli such as pathogen attack, hormone signaling, abiotic stresses, or during cell wall organization and plant morphogenesis. Monitoring ROS in plant cells has been limited to biochemical assays and use of fluorescent probes, however, the irreversible oxidation of the fluorescent dyes make it impossible to visualize dynamic changes of ROS. Hyper is a recently developed live cell probe for H2O2 and consists of a circularly permutated YFP (cpYFP) inserted into the regulatory domain of the Escherichia coli hydrogen peroxide (H2O2) sensor OxyR rendering it a H2O2 specific ratiometric, and therefore quantitative probe. Herein, we describe a protocol for using Hyper as a dynamic probe for H2O2 in Arabidopsis with virtually unlimited potential to detect H2O2 throughout the plant and under a broad range of developmental and environmental conditions.