Publications by authors named "Beller H"

Article Synopsis
  • - Radical enzymes, particularly the glycyl radical enzyme (GRE) family, perform complex chemical reactions crucial for various biological functions, and they all include a key glycine residue that forms a vital α-carbon radical.
  • - Researchers found numerous noncanonical GRE homologs that use alanine, serine, or threonine instead of glycine, challenging previous assumptions about radical enzyme structure.
  • - These newly identified aminoacyl radical enzymes (AAREs) can generate stable α-carbon radicals when activated by specific partner enzymes and are common in microbial genomes, highlighting their significance and potential for novel chemical reactions.
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Objectives: To assess the prevalence and predictors of chronic pelvic pain in a general urology population presenting for evaluation of unrelated non-painful complaints.Generalized pelvic pain is estimated to afflict between 6% and 26% of women and is often multifactorial in aetiology. A paucity of prospective research exists to characterize chronic pelvic pain patterns and to understand related predictors.

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Introduction: COVID-19 has brought unprecedented challenges to the delivery of urological care. Following rapid implementation of remote video visits at our tertiary academic medical center serving a large rural population we describe and assess our experience with planned video visits and ongoing scheduling efforts.

Methods: Patients scheduled for video visits between April 14 and April 27, 2020 were included.

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Introduction: Telemedicine video visits are an under-utilized form of delivering health care. However due to the COVID-19 pandemic, practices are rapidly adapting telemedicine for patient care. We describe our experience in rapidly introducing video visits in a tertiary academic pediatric urology practice, serving primarily rural patients during the COVID-19 pandemic.

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Objective: To identify the incidence of radiation-induced urologic complication requiring procedural intervention following high-dose radiotherapy for cervical carcinoma, and to identify predictors of complication occurrence.

Materials And Methods: We performed a retrospective chart review of cervical cancer patients undergoing radiotherapy with primary focus on procedural complications (Clavien-Dindo ≥ III). Clinical data were collected including radiation dose, procedure performed, timing of complication, and need for additional procedures.

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Rapid evolution of telemedicine technology requires procedures in telemedicine to adapt frequently. An example in urology, telecystoscopy, allows certified advanced practice providers to perform cystoscopy, endoscopic examination of the bladder, in rural areas with real-time interpretation and guidance by an off-site urologist. We have previously shown the technological infrastructure for optimized video quality.

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Soil microbial biomass can reach its annual maximum pool size beneath the winter snowpack and is known to decline abruptly following snowmelt in seasonally snow-covered ecosystems. Observed differences in winter versus summer microbial taxonomic composition also suggests that phylogenetically conserved traits may permit winter- versus summer-adapted microorganisms to occupy distinct niches. In this study, we sought to identify archaea, bacteria, and fungi that are associated with the soil microbial bloom overwinter and the subsequent biomass collapse following snowmelt at a high-altitude watershed in central Colorado, United States.

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The long-term stability of U(IV) solid phases in anaerobic aquifers depends upon their reactivity in the presence of oxidizing chemical species and microbial catalysts. We performed flow-through column experiments under anaerobic conditions to investigate the mechanisms and dissolution rates of biogenic, noncrystalline UO(s) by chemical oxidants (nitrate and/or nitrite) or by , a widespread, denitrifying, chemolithoautotrophic model bacterium. Dissolution rates of UO(s) with dissolved nitrite were approximately 5 to 10 times greater than with nitrate alone.

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Purpose: In order to expand the availability of cystoscopy to underserved areas we have proposed using advanced practice providers to perform cystoscopy with real-time interpretation by the urologist on a telemedicine platform, termed "tele-cystoscopy." The purpose of this study is to have blinded external reviewers retrospectively compare multisite, prospectively collected video data from tele-cystoscopy with the video of traditional cystoscopy in terms of video clarity, practitioner proficiency and diagnostic capability.

Materials And Methods: Each patient underwent tele-cystoscopy by a trained advanced practice provider and traditional cystoscopy with an onsite urologist.

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We recently reported the discovery of phenylacetate decarboxylase (PhdB), representing one of only ten glycyl-radical-enzyme reaction types known, and a promising biotechnological tool for first-time biochemical synthesis of toluene from renewable resources. Here, we used experimental and computational data to evaluate the plausibility of three candidate PhdB mechanisms, involving either attack at the phenylacetate methylene carbon or carboxyl group [via H-atom abstraction from COOH or single-electron oxidation of COO (Kolbe-type decarboxylation)]. In vitro experimental data included assays with F-labeled phenylacetate, kinetic studies, and tests with site-directed PhdB mutants; computational data involved estimation of reaction energetics using density functional theory (DFT).

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Isoprenol (3-methyl-3-buten-1-ol) is a drop-in biofuel and a precursor for commodity chemicals. Biological production of isoprenol via the mevalonate pathway has been developed and optimized extensively in Escherichia coli, but high ATP requirements and isopentenyl diphosphate (IPP) toxicity have made it difficult to achieve high titer, yield, and large-scale production. To overcome these limitations, an IPP-bypass pathway was previously developed using the promiscuous activity of diphosphomevalonate decarboxylase, and enabled the production of isoprenol at a comparable yield and titer to the original pathway.

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Article Synopsis
  • - This study focuses on understanding the carbon sources for active microbial populations in groundwater by analyzing the RNA of these microbes, particularly their ribosomal RNA (rRNA) signatures.
  • - A method was developed to extract and date RNA from a shallow aquifer in Colorado, revealing that over half of the microbial RNA was linked to autotrophic organisms, which create their own food from inorganic sources.
  • - The research highlights the significance of autotrophy in subsurface microbial communities and suggests that these microbes preferentially utilize dissolved organic matter rather than sedimentary sources in alluvial aquifers.
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The conversion of municipal solid waste (MSW) and lignocellulosic biomass blends to methyl ketones (MKs) was investigated by using bioderived ionic liquid (bionic liquid)-based hydrolysates followed by fermentation with an engineered Escherichia coli strain. The hydrolysates were produced by a one-pot process using six types of MSW-biomass blends, choline-based bionic liquids, and commercial enzymes. Based on the sugar yields, one blend (corn stover/MSW=95:5, w/w) and two bionic liquids {cholinium lysinate ([Ch][Lys]) and cholinium aspartate ([Ch] [Asp])} were selected for scale-up studies.

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Hexavalent chromium Cr(VI) is a common inorganic contaminant in industrial areas and represents a serious threat to human health due its toxicity. Here we report experimental results from a field-scale investigation of Cr(VI) bio-immobilization at Hanford 100H reservation, a U.S Department of Energy facility (Washington State, USA).

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The Design-Build-Test-Learn (DBTL) cycle, facilitated by exponentially improving capabilities in synthetic biology, is an increasingly adopted metabolic engineering framework that represents a more systematic and efficient approach to strain development than historical efforts in biofuels and biobased products. Here, we report on implementation of two DBTL cycles to optimize 1-dodecanol production from glucose using 60 engineered Escherichia coli MG1655 strains. The first DBTL cycle employed a simple strategy to learn efficiently from a relatively small number of strains (36), wherein only the choice of ribosome-binding sites and an acyl-ACP/acyl-CoA reductase were modulated in a single pathway operon including genes encoding a thioesterase (UcFatB1), an acyl-ACP/acyl-CoA reductase (Maqu_2507, Maqu_2220, or Acr1), and an acyl-CoA synthetase (FadD).

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Plants are an attractive sourceof renewable carbon for conversion to biofuels and bio-based chemicals. Conversion strategies often use a fraction of the biomass, focusing on sugars from cellulose and hemicellulose. Strategies that use plant components, such as aromatics and amino acids, may improve the efficiency of biomass conversion.

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Microbial toluene biosynthesis was reported in anoxic lake sediments more than three decades ago, but the enzyme catalyzing this biochemically challenging reaction has never been identified. Here we report the toluene-producing enzyme PhdB, a glycyl radical enzyme of bacterial origin that catalyzes phenylacetate decarboxylation, and its cognate activating enzyme PhdA, a radical S-adenosylmethionine enzyme, discovered in two distinct anoxic microbial communities that produce toluene. The unconventional process of enzyme discovery from a complex microbial community (>300,000 genes), rather than from a microbial isolate, involved metagenomics- and metaproteomics-enabled biochemistry, as well as in vitro confirmation of activity with recombinant enzymes.

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We previously engineered Escherichia coli to overproduce medium- to long-chain saturated and monounsaturated methyl ketones, which could potentially be applied as diesel fuel blending agents or in the flavor and fragrance industry. Recent efforts at strain optimization have focused on cofactor balance, as fatty acid-derived pathways face the systematic metabolic challenge of net NADPH consumption (in large part, resulting from the key fatty acid biosynthetic enzyme FabG [β-ketoacyl-ACP reductase]) and net NADH production. In this study, we attempted to mitigate cofactor imbalance by heterologously expressing NADH-dependent, rather than NADPH-dependent, versions of FabG identified in previous studies.

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Background: We previously developed an E. coli strain that overproduces medium-chain methyl ketones for potential use as diesel fuel blending agents or as flavors and fragrances. To date, the strain's performance has been optimized during growth with glucose.

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Hexavalent chromium, Cr(VI), is a widespread and toxic groundwater contaminant. Reductive immobilization to Cr(III) is a treatment option, but its success depends on the long-term potential for reduced chromium precipitates to remain immobilized under oxidizing conditions. In this unique long-term study, aquifer sediments subjected to reductive Cr(VI) immobilization under different biogeochemical regimes were tested for their susceptibility to reoxidation.

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Three-dimensional variably saturated flow and multicomponent biogeochemical reactive transport modeling, based on published and newly generated data, is used to better understand the interplay of hydrology, geochemistry, and biology controlling the cycling of carbon, nitrogen, oxygen, iron, sulfur, and uranium in a shallow floodplain. In this system, aerobic respiration generally maintains anoxic groundwater below an oxic vadose zone until seasonal snowmelt-driven water table peaking transports dissolved oxygen (DO) and nitrate from the vadose zone into the alluvial aquifer. The response to this perturbation is localized due to distinct physico-biogeochemical environments and relatively long time scales for transport through the floodplain aquifer and vadose zone.

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Organic matter deposits in alluvial aquifers have been shown to result in the formation of naturally reduced zones (NRZs), which can modulate aquifer redox status and influence the speciation and mobility of metals, affecting groundwater geochemistry. In this study, we sought to better understand how natural organic matter fuels microbial communities within anoxic biogeochemical hot spots (NRZs) in a shallow alluvial aquifer at the Rifle (CO) site. We conducted a 20-day microcosm experiment in which NRZ sediments, which were enriched in buried woody plant material, served as the sole source of electron donors and microorganisms.

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Tropical forests absorb large amounts of atmospheric CO through photosynthesis but elevated temperatures suppress this absorption and promote monoterpene emissions. Using CO labeling, here we show that monoterpene emissions from tropical leaves derive from recent photosynthesis and demonstrate distinct temperature optima for five groups (Groups 1-5), potentially corresponding to different enzymatic temperature-dependent reaction mechanisms within β-ocimene synthases. As diurnal and seasonal leaf temperatures increased during the Amazonian 2015 El Niño event, leaf and landscape monoterpene emissions showed strong linear enrichments of β-ocimenes (+4.

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Anaerobic bacterial biosynthesis of toluene from phenylacetate was reported more than two decades ago, but the biochemistry underlying this novel metabolism has never been elucidated. Here we report results of in vitro characterization studies of a novel phenylacetate decarboxylase from an anaerobic, sewage-derived enrichment culture that quantitatively produces toluene from phenylacetate; complementary metagenomic and metaproteomic analyses are also presented. Among the noteworthy findings is that this enzyme is not the well-characterized clostridial p-hydroxyphenylacetate decarboxylase (CsdBC).

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Chemolithoautotrophic bacteria that oxidize reduced sulfur compounds, such as HS, while fixing CO are an untapped source of renewable bioproducts from sulfide-laden waste, such as municipal wastewater. In this study, we report engineering of the chemolithoautotrophic bacterium to produce up to 52-fold more fatty acids than the wild-type strain when grown with thiosulfate and CO. A modified thioesterase gene from (') was integrated into the chromosome under the control of P or one of two native promoters.

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