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1.
World J Urol ; 40(5): 1203-1209, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35166893

RESUMEN

PURPOSE: We sought to objectively compare laser fiber degradation for holmium laser enucleation of the prostate (HoLEP) cases performed with 550 µm standard fibers versus 550 µm Moses 2.0 fiber in BPH mode on a macroscopic and microscopic level. METHODS: We prospectively collected outcomes for 50 standardized HoLEP cases using 550 µm Moses fiber with 2.0 BPH mode compared to our historical cohort of 50 patients using 550 µm standard fibers on regular mode. Macroscopic degradation length was the difference in length of exposed fiber at the start and end of each case. Five consecutive 550 µm standard fibers, five 550 µm Moses fibers and their respective controls underwent novel utilization of three objective corroborating imaging techniques: Brightfield high resolution microscopy, high resolution 3-D microCT and Confocal Reflection Surface Analysis. Mann-Whitney U, 2-tailed T tests and Chi-squared tests were used. RESULTS: Standard fibers demonstrated greater degradation than the Moses fibers with 2.0 BPH mode [2.9 cm (IQR 1.7-4.3 cm) vs 0.2 cm (IQR 0.1-0.4 cm), p < 0.01]. This difference remained significant when comparing degradation per energy used, per minute enucleation and per gram enucleated (all p < 0.05). None of the cases with Moses fiber and 2.0 BPH mode required intraoperative interruption to re-strip the fiber. Objective fiber degradation by three microscopic techniques confirmed more damage to the standard fibers with regular mode. CONCLUSION: Overall, use of the 550 µm Moses fiber with 2.0 BPH mode resulted in less fiber degradation compared to a standard 550 µm fiber with regular mode as confirmed using 4 corroborating macroscopic and microscopic techniques.


Asunto(s)
Terapia por Láser , Láseres de Estado Sólido , Hiperplasia Prostática , Resección Transuretral de la Próstata , Holmio , Humanos , Terapia por Láser/métodos , Láseres de Estado Sólido/uso terapéutico , Masculino , Próstata/cirugía , Hiperplasia Prostática/cirugía , Tecnología , Resultado del Tratamiento
2.
Environ Sci Technol ; 54(16): 10128-10140, 2020 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-32693580

RESUMEN

Microbial iron reduction is a ubiquitous biogeochemical process driven by diverse microorganisms in a variety of environments. However, it is often difficult to separate the biological from the geochemical controls on bioreduction of Fe(III) oxides. Here, we investigated the primary driving factor(s) that mediate secondary iron mineral formation over a broad range of environmental conditions using a single dissimilatory iron reducer, Orenia metallireducens strain Z6. A total of 17 distinct geochemical conditions were tested with differing pH (6.5-8.5), temperature (22-50 °C), salinity (2-20% NaCl), anions (phosphate and sulfate), electron shuttle (anthraquinone-2,6-disulfonate), and Fe(III) oxide mineralogy (ferrihydrite, lepidocrocite, goethite, hematite, and magnetite). The observed rates and extent of iron reduction differed significantly with kint between 0.186 and 1.702 mmol L-1 day-1 and Fe(II) production ranging from 6.3% to 83.7% of the initial Fe(III). Using X-ray absorption and scattering techniques (EXAFS and XRD), we identified and assessed the relationship between secondary minerals and the specific environmental conditions. It was inferred that the observed bifurcation of the mineralization pathways may be mediated by differing extents of Fe(II) sorption on the remaining Fe(III) minerals. These results expand our understanding of the controls on biomineralization during microbial iron reduction and aid the development of practical applications.


Asunto(s)
Compuestos Férricos , Firmicutes , Biomineralización , Hierro , Minerales , Oxidación-Reducción
3.
Environ Sci Technol ; 53(5): 2778-2787, 2019 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-30673286

RESUMEN

Subsurface environments often contain mixtures of contaminants in which the microbial degradation of one pollutant may be inhibited by the toxicity of another. Agricultural settings exemplify these complex environments, where antimicrobial leachates may inhibit nitrate bioreduction, and are the motivation to address this fundamental ecological response. In this study, a microfluidic reactor was fabricated to create diffusion-controlled concentration gradients of nitrate and ciprofloxacin under anoxic conditions in order to evaluate the ability of Shewanella oneidenisis MR-1 to reduce the former in the presence of the latter. Results show a surprising ecological response, where swimming motility allow S. oneidensis MR-1 to accumulate and maintain metabolic activity for nitrate reduction in regions with toxic ciprofloxacin concentrations (i.e., 50× minimum inhibitory concentration, MIC), despite the lack of observed antibiotic resistance. Controls with limited nutrient flux and a nonmotile mutant (Δ flag) show that cells cannot colonize antibiotic rich microenvironments, and this results in minimal metabolic activity for nitrate reduction. These results demonstrate that under anoxic, nitrate-reducing conditions, motility can control microbial habitability and metabolic activity in spatially heterogeneous toxic environments.


Asunto(s)
Shewanella , Ciprofloxacina , Microfluídica , Nitratos , Óxidos de Nitrógeno
4.
Environ Sci Technol ; 53(14): 7996-8005, 2019 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-31269400

RESUMEN

A microfluidic gradient chamber (MGC) and a homogeneous batch culturing system were used to evaluate whether spatial concentration gradients of the antibiotic ciprofloxacin allow development of greater antibiotic resistance in Escherichia coli strain 307 (E. coli 307) compared to exclusively temporal concentration gradients, as indicated in an earlier study. A linear spatial gradient of ciprofloxacin and Luria-Bertani broth (LB) medium was established and maintained by diffusion over 5 days across a well array in the MGC, with relative concentrations along the gradient of 1.7-7.7× the original minimum inhibitory concentration (MICoriginal). The E. coli biomass increased in wells with lower ciprofloxacin concentrations, and only a low level of resistance to ciprofloxacin was detected in the recovered cells (∼2× MICoriginal). Homogeneous batch culture experiments were performed with the same temporal exposure history to ciprofloxacin concentration, the same and higher initial cell densities, and the same and higher nutrient (i.e., LB) concentrations as in the MGC. In all batch experiments, E. coli 307 developed higher ciprofloxacin resistance after exposure, ranging from 4 to 24× MICoriginal in all replicates. Hence, these results suggest that the presence of spatial gradients appears to reduce the driving force for E. coli 307 adaptation to ciprofloxacin, which suggests that results from batch experiments may over predict the development of antibiotic resistance in natural environments.


Asunto(s)
Ciprofloxacina , Infecciones por Escherichia coli , Antibacterianos , Farmacorresistencia Bacteriana , Escherichia coli , Humanos , Pruebas de Sensibilidad Microbiana
5.
Environ Sci Technol ; 51(1): 232-242, 2017 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-27943672

RESUMEN

Fermentative iron-reducing organisms have been identified in a variety of environments. Instead of coupling iron reduction to respiration, they have been consistently observed to use ferric iron minerals as an electron sink for fermentation. In the present study, a fermentative iron reducer, Orenia metallireducens strain Z6, was shown to use iron reduction to enhance fermentation not only by consuming electron equivalents, but also by generating alkalinity that effectively buffers the pH. Fermentation of glucose by this organism in the presence of a ferric oxide mineral, hematite (Fe2O3), resulted in enhanced glucose decomposition compared with fermentation in the absence of an iron source. Parallel evidence (i.e., genomic reconstruction, metabolomics, thermodynamic analyses, and calculation of electron transfer) suggested hematite reduction as a proton-consuming reaction effectively consumed acid produced by fermentation. The buffering effect of hematite was further supported by a greater extent of glucose utilization by strain Z6 in media with increasing buffer capacity. Such maintenance of a stable pH through hematite reduction for enhanced glucose fermentation complements the thermodynamic interpretation of interactions between microbial iron reduction and other biogeochemical processes. This newly discovered feature of iron reducer metabolism also has significant implications for groundwater management and contaminant remediation by providing microbially mediated buffering systems for the associated microbial and/or chemical reactions.


Asunto(s)
Compuestos Férricos/química , Hierro/química , Tampones (Química) , Minerales/química , Oxidación-Reducción
6.
Appl Environ Microbiol ; 82(21): 6440-6453, 2016 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-27565620

RESUMEN

A novel halophilic and metal-reducing bacterium, Orenia metallireducens strain Z6, was isolated from briny groundwater extracted from a 2.02 km-deep borehole in the Illinois Basin, IL. This organism shared 96% 16S rRNA gene similarity with Orenia marismortui but demonstrated physiological properties previously unknown for this genus. In addition to exhibiting a fermentative metabolism typical of the genus Orenia, strain Z6 reduces various metal oxides [Fe(III), Mn(IV), Co(III), and Cr(VI)], using H2 as the electron donor. Strain Z6 actively reduced ferrihydrite over broad ranges of pH (6 to 9.6), salinity (0.4 to 3.5 M NaCl), and temperature (20 to 60°C). At pH 6.5, strain Z6 also reduced more crystalline iron oxides, such as lepidocrocite (γ-FeOOH), goethite (α-FeOOH), and hematite (α-Fe2O3). Analysis of X-ray absorption fine structure (XAFS) following Fe(III) reduction by strain Z6 revealed spectra from ferrous secondary mineral phases consistent with the precipitation of vivianite [Fe3(PO4)2] and siderite (FeCO3). The draft genome assembled for strain Z6 is 3.47 Mb in size and contains 3,269 protein-coding genes. Unlike the well-understood iron-reducing Shewanella and Geobacter species, this organism lacks the c-type cytochromes for typical Fe(III) reduction. Strain Z6 represents the first bacterial species in the genus Orenia (order Halanaerobiales) reported to reduce ferric iron minerals and other metal oxides. This microbe expands both the phylogenetic and physiological scopes of iron-reducing microorganisms known to inhabit the deep subsurface and suggests new mechanisms for microbial iron reduction. These distinctions from other Orenia spp. support the designation of strain Z6 as a new species, Orenia metallireducens sp. nov. IMPORTANCE: A novel iron-reducing species, Orenia metallireducens sp. nov., strain Z6, was isolated from groundwater collected from a geological formation located 2.02 km below land surface in the Illinois Basin, USA. Phylogenetic, physiologic, and genomic analyses of strain Z6 found it to have unique properties for iron reducers, including (i) active microbial iron-reducing capacity under broad ranges of temperatures (20 to 60°C), pHs (6 to 9.6), and salinities (0.4 to 3.5 M NaCl), (ii) lack of c-type cytochromes typically affiliated with iron reduction in Geobacter and Shewanella species, and (iii) being the only member of the Halanaerobiales capable of reducing crystalline goethite and hematite. This study expands the scope of phylogenetic affiliations, metabolic capacities, and catalytic mechanisms for iron-reducing microbes.


Asunto(s)
Firmicutes/clasificación , Firmicutes/aislamiento & purificación , Sedimentos Geológicos/microbiología , Metales/metabolismo , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , ADN Ribosómico , Compuestos Férricos/metabolismo , Firmicutes/genética , Firmicutes/metabolismo , Genes de ARNr , Genoma Bacteriano , Geobacter/metabolismo , Compuestos de Hierro/metabolismo , Minerales/metabolismo , Oxidación-Reducción , Filogenia , ARN Ribosómico 16S , Shewanella/metabolismo
7.
Int J Syst Evol Microbiol ; 66(10): 3964-3971, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27406851

RESUMEN

A Gram-stain-negative, microaerophilic rod-shaped organism designated as strain Z9T was isolated from groundwater of 1.7 km depth from the Mt. Simon Sandstone of the Illinois Basin, Illinois, USA. Cells of strain Z9T were rod shaped with dimensions of 0.3×(1-10) µm and stained Gram-negative. Strain Z9T grew within the temperature range 20-60 °C (optimum at 30-40 °C), between pH 5 and 8 (optimum 5.2-5.8) and under salt concentrations of 1-5 % (w/v) NaCl (optimum 2.5 % NaCl). In addition to growth by fermentation and nitrate reduction, this strain was able to reduce Fe(III), Mn(IV), Co(III) and Cr(VI) when H2 or organic carbon was available as the electron donor, but did not actively reduce oxidized sulfur compounds (e.g. sulfate, thiosulfate or S0). The G+C content of the DNA from strain Z9T was 36.1 mol%. Phylogenetic analysis of the 16S rRNA gene from strain Z9T showed that it belongs to the class Bacilli and shares 97 % sequence similarity with the only currently characterized member of the genus Tepidibacillus, T.fermentans. Based on the physiological distinctness and phylogenetic information, strain Z9T represents a novel species within the genus Tepidibacillus, for which the name Tepidibacillus decaturensis sp. nov. is proposed. The type strain is Z9T (=ATCC BAA-2644T=DSM 103037T).


Asunto(s)
Bacillaceae/clasificación , Agua Subterránea/microbiología , Hierro/metabolismo , Filogenia , Bacillaceae/genética , Bacillaceae/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Illinois , Oxidación-Reducción , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
8.
Environ Sci Technol ; 49(20): 12094-104, 2015 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-26348257

RESUMEN

The ability of Pseudomonas stutzeri strain DCP-Ps1 to drive CaCO3 biomineralization has been investigated in a microfluidic flowcell (i.e., micromodel) that simulates subsurface porous media. Results indicate that CaCO3 precipitation occurs during NO3(-) reduction with a maximum saturation index (SIcalcite) of ∼1.56, but not when NO3(-) was removed, inactive biomass remained, and pH and alkalinity were adjusted to SIcalcite ∼ 1.56. CaCO3 precipitation was promoted by metabolically active cultures of strain DCP-Ps1, which at similar values of SIcalcite, have a more negative surface charge than inactive strain DCP-Ps1. A two-stage NO3(-) reduction (NO3(-) → NO2(-) → N2) pore-scale reactive transport model was used to evaluate denitrification kinetics, which was observed in the micromodel as upper (NO3(-) reduction) and lower (NO2(-) reduction) horizontal zones of biomass growth with CaCO3 precipitation exclusively in the lower zone. Model results are consistent with two biomass growth regions and indicate that precipitation occurred in the lower zone because the largest increase in pH and alkalinity is associated with NO2(-) reduction. CaCO3 precipitates typically occupied the entire vertical depth of pores and impacted porosity, permeability, and flow. This study provides a framework for incorporating microbial activity in biogeochemistry models, which often base biomineralization only on SI (caused by biotic or abiotic reactions) and, thereby, underpredict the extent of this complex process. These results have wide-ranging implications for understanding reactive transport in relevance to groundwater remediation, CO2 sequestration, and enhanced oil recovery.


Asunto(s)
Carbonato de Calcio/metabolismo , Modelos Teóricos , Pseudomonas stutzeri/metabolismo , Biomasa , Carbonato de Calcio/química , Precipitación Química , Desnitrificación , Agua Subterránea , Concentración de Iones de Hidrógeno , Cinética , Minerales/química , Minerales/metabolismo , Nitratos/química , Nitratos/metabolismo , Permeabilidad , Porosidad
9.
BMC Genomics ; 15: 591, 2014 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-25016412

RESUMEN

BACKGROUND: Corals represent symbiotic meta-organisms that require harmonization among the coral animal, photosynthetic zooxanthellae and associated microbes to survive environmental stresses. We investigated integrated-responses among coral and zooxanthellae in the scleractinian coral Acropora formosa in response to an emerging marine pollutant, the munitions constituent, 1,3,5-trinitro-1,3,5 triazine (RDX; 5 day exposures to 0 (control), 0.5, 0.9, 1.8, 3.7, and 7.2 mg/L, measured in seawater). RESULTS: RDX accumulated readily in coral soft tissues with bioconcentration factors ranging from 1.1 to 1.5. Next-generation sequencing of a normalized meta-transcriptomic library developed for the eukaryotic components of the A. formosa coral holobiont was leveraged to conduct microarray-based global transcript expression analysis of integrated coral/zooxanthellae responses to the RDX exposure. Total differentially expressed transcripts (DET) increased with increasing RDX exposure concentrations as did the proportion of zooxanthellae DET relative to the coral animal. Transcriptional responses in the coral demonstrated higher sensitivity to RDX compared to zooxanthellae where increased expression of gene transcripts coding xenobiotic detoxification mechanisms (i.e. cytochrome P450 and UDP glucuronosyltransferase 2 family) were initiated at the lowest exposure concentration. Increased expression of these detoxification mechanisms was sustained at higher RDX concentrations as well as production of a physical barrier to exposure through a 40% increase in mucocyte density at the maximum RDX exposure. At and above the 1.8 mg/L exposure concentration, DET coding for genes involved in central energy metabolism, including photosynthesis, glycolysis and electron-transport functions, were decreased in zooxanthellae although preliminary data indicated that zooxanthellae densities were not affected. In contrast, significantly increased transcript expression for genes involved in cellular energy production including glycolysis and electron-transport pathways was observed in the coral animal. CONCLUSIONS: Transcriptional network analysis for central energy metabolism demonstrated highly correlated responses to RDX among the coral animal and zooxanthellae indicative of potential compensatory responses to lost photosynthetic potential within the holobiont. These observations underscore the potential for complex integrated responses to RDX exposure among species comprising the coral holobiont and highlight the need to understand holobiont-species interactions to accurately assess pollutant impacts.


Asunto(s)
Antozoos/genética , Dinoflagelados/genética , Transcriptoma/efectos de los fármacos , Triazinas/farmacología , Contaminantes Químicos del Agua/farmacología , Animales , Antozoos/efectos de los fármacos , Antozoos/metabolismo , Dinoflagelados/efectos de los fármacos , Dinoflagelados/metabolismo , Anotación de Secuencia Molecular , Análisis de Secuencia por Matrices de Oligonucleótidos , Estrés Fisiológico , Simbiosis
10.
Environ Microbiol ; 16(6): 1695-708, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24238218

RESUMEN

A low-diversity microbial community, dominated by the γ-proteobacterium Halomonas sulfidaeris, was detected in samples of warm saline formation porewater collected from the Cambrian Mt. Simon Sandstone in the Illinois Basin of the North American Midcontinent (1.8 km/5872 ft burial depth, 50°C, pH 8, 181 bars pressure). These highly porous and permeable quartz arenite sandstones are directly analogous to reservoirs around the world targeted for large-scale hydrocarbon extraction, as well as subsurface gas and carbon storage. A new downhole low-contamination subsurface sampling probe was used to collect in situ formation water samples for microbial environmental metagenomic analyses. Multiple lines of evidence suggest that this H. sulfidaeris-dominated subsurface microbial community is indigenous and not derived from drilling mud microbial contamination. Data to support this includes V1-V3 pyrosequencing of formation water and drilling mud, as well as comparison with previously published microbial analyses of drilling muds in other sites. Metabolic pathway reconstruction, constrained by the geology, geochemistry and present-day environmental conditions of the Mt. Simon Sandstone, implies that H. sulfidaeris-dominated subsurface microbial community may utilize iron and nitrogen metabolisms and extensively recycle indigenous nutrients and substrates. The presence of aromatic compound metabolic pathways suggests this microbial community can readily adapt to and survive subsurface hydrocarbon migration.


Asunto(s)
Halomonas/genética , Microbiología del Agua , Genes Bacterianos , Illinois , Redes y Vías Metabólicas/genética , Metagenoma , Microbiota/genética , Anotación de Secuencia Molecular , Datos de Secuencia Molecular , Filogenia , Cuarzo , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
11.
Sci Rep ; 14(1): 12222, 2024 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-38806601

RESUMEN

Calcification of aortic valve leaflets is a growing mortality threat for the 18 million human lives claimed globally each year by heart disease. Extensive research has focused on the cellular and molecular pathophysiology associated with calcification, yet the detailed composition, structure, distribution and etiological history of mineral deposition remains unknown. Here transdisciplinary geology, biology and medicine (GeoBioMed) approaches prove that leaflet calcification is driven by amorphous calcium phosphate (ACP), ACP at the threshold of transformation toward hydroxyapatite (HAP) and cholesterol biomineralization. A paragenetic sequence of events is observed that includes: (1) original formation of unaltered leaflet tissues: (2) individual and coalescing 100's nm- to 1 µm-scale ACP spherules and cholesterol crystals biomineralizing collagen fibers and smooth muscle cell myofilaments; (3) osteopontin coatings that stabilize ACP and collagen containment of nodules preventing exposure to the solution chemistry and water content of pumping blood, which combine to slow transformation to HAP; (4) mm-scale nodule growth via ACP spherule coalescence, diagenetic incorporation of altered collagen and aggregation with other ACP nodules; and (5) leaflet diastole and systole flexure causing nodules to twist, fold their encasing collagen fibers and increase stiffness. These in vivo mechanisms combine to slow leaflet calcification and establish previously unexplored hypotheses for testing novel drug therapies and clinical interventions as viable alternatives to current reliance on surgical/percutaneous valve implants.


Asunto(s)
Válvula Aórtica , Calcinosis , Fosfatos de Calcio , Colágeno , Osteopontina , Fosfatos de Calcio/metabolismo , Humanos , Válvula Aórtica/metabolismo , Válvula Aórtica/patología , Osteopontina/metabolismo , Calcinosis/metabolismo , Calcinosis/prevención & control , Colágeno/metabolismo , Durapatita/metabolismo , Durapatita/química , Estenosis de la Válvula Aórtica/metabolismo , Estenosis de la Válvula Aórtica/patología , Colesterol/metabolismo
12.
Sci Rep ; 12(1): 18371, 2022 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-36319741

RESUMEN

Shock wave lithotripsy (SWL) is an effective and commonly applied clinical treatment for human kidney stones. Yet the success of SWL is counterbalanced by the risk of retained fragments causing recurrent stone formation, which may require retreatment. This study has applied GeoBioMed experimental and analytical approaches to determine the size frequency distribution, fracture patterns, and reactive surface area of SWL-derived particles within the context of their original crystal growth structure (crystalline architecture) as revealed by confocal autofluorescence (CAF) and super-resolution autofluorescence (SRAF) microscopy. Multiple calcium oxalate (CaOx) stones were removed from a Mayo Clinic patient using standard percutaneous nephrolithotomy (PCNL) and shock pulse lithotripsy (SPL). This produced approximately 4-12 mm-diameter PCNL-derived fragments that were experimentally treated ex vivo with SWL to form hundreds of smaller particles. Fractures propagated through the crystalline architecture of PCNL-derived fragments in a variety of geometric orientations to form rectangular, pointed, concentrically spalled, and irregular SWL-derived particles. Size frequency distributions ranged from fine silt (4-8 µm) to very fine pebbles (2-4 mm), according to the Wentworth grain size scale, with a mean size of fine sand (125-250 µm). Importantly, these SWL-derived particles are smaller than the 3-4 mm-diameter detection limit of clinical computed tomography (CT) techniques and can be retained on internal kidney membrane surfaces. This creates clinically undetectable crystallization seed points with extremely high reactive surface areas, which dramatically enhance the multiple events of crystallization and dissolution (diagenetic phase transitions) that may lead to the high rates of CaOx kidney stone recurrence after SWL treatment.


Asunto(s)
Cálculos Renales , Litotricia , Nefrolitotomía Percutánea , Humanos , Oxalato de Calcio , Litotricia/métodos , Cálculos Renales/terapia , Riñón , Resultado del Tratamiento
13.
Sci Rep ; 12(1): 1239, 2022 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-35075188

RESUMEN

Travertine crystal growth ripples are used to reconstruct the early hydraulic history of the Anio Novus aqueduct of ancient Rome. These crystalline morphologies deposited within the aqueduct channel record the hydraulic history of gravity-driven turbulent flow at the time of Roman operation. The wavelength, amplitude, and steepness of these travertine crystal growth ripples indicate that large-scale sustained aqueduct flows scaled directly with the thickness of the aqueous viscous sublayer. Resulting critical shear Reynolds numbers are comparable with those reconstructed from heat/mass transfer crystalline ripples formed in other natural and engineered environments. This includes sediment transport in rivers, lakes, and oceans, chemical precipitation and dissolution in caves, and melting and freezing in ice. Where flow depth and perimeter could be reconstructed from the distribution and stratigraphy of the travertine within the Anio Novus aqueduct, flow velocity and rate have been quantified by deriving roughness-flow relationships that are independent of water temperature. More generally, under conditions of near-constant water temperature and kinematic viscosity within the Anio Novus aqueduct channel, the travertine crystal growth ripple wavelengths increased with decreasing flow velocity, indicating that systematic changes took place in flow rate during travertine deposition. This study establishes that travertine crystal growth ripples such as those preserved in the Anio Novus provide a sensitive record of past hydraulic conditions, which can be similarly reconstructed from travertine deposited in other ancient water conveyance and storage systems around the world.

14.
Sci Total Environ ; 779: 146503, 2021 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-34030234

RESUMEN

In order to explore the impact of antibiotics on the bacterial metabolic cycling of nitrate within contaminated soil and groundwater environments, we compared the effects of polymyxin B (PMB) and ciprofloxacin (CIP) concentration gradients on the distribution and activity of a wild type (WT) and a flagella deficient mutant (Δflag) of Shewanella oneidensis MR-1 in a microfluidic gradient chamber (MGC). Complementary batch experiments were performed to measure bacteriostatic versus bactericidal concentrations of the two antibiotics, as well as their effect on nitrate reduction. Prior work demonstrated that PMB disrupts cell membranes while CIP inhibits DNA synthesis. Consistent with these modes of action, batch results from this work show that PMB is bactericidal at lower concentrations than CIP relative to their respective minimum inhibitory concentrations (MICs) (≥5× MICPMB vs. ≥20× MICCIP). Concentration gradients from 0 to 50× the MIC of both antibiotics were established in the MGC across a 2-cm interconnected pore network, with nutrients injected at both concentration boundaries. The WT cells could only access and reduce nitrate in regions of the MGC with PMB at <18× MICPMB, whereas this occurred with CIP up to 50× MICCIP; and cells extracted from these MGCs showed no antibiotic resistance. The distribution of Δflag cells was further limited to lower antibiotic concentrations (≤1× MICPMB, ≤43× MICCIP) due to inability of movement. These results indicate that S. oneidensis access and reduce nitrate in bactericidal regions via chemotactic migration without development of antibiotic resistance, and that this migration is inhibited by acutely lethal bactericidal levels of antibiotics.


Asunto(s)
Antibacterianos , Nitratos , Antibacterianos/toxicidad , Ciprofloxacina/toxicidad , Farmacorresistencia Microbiana/genética , Pruebas de Sensibilidad Microbiana , Microfluídica , Nitratos/toxicidad , Shewanella
15.
ISME J ; 15(10): 2920-2932, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33927341

RESUMEN

Spatial concentration gradients of antibiotics are prevalent in the natural environment. Yet, the microbial response in these heterogeneous systems remains poorly understood. We used a microfluidic reactor to create an artificial microscopic ecosystem that generates diffusive gradients of solutes across interconnected microenvironments. With this reactor, we showed that chemotaxis toward a soluble electron acceptor (nitrate) allowed Shewanella oneidensis MR-1 to inhabit and sustain metabolic activity in highly toxic regions of the antibiotic ciprofloxacin (>80× minimum inhibitory concentration, MIC). Acquired antibiotic resistance was not observed for cells extracted from the reactor, so we explored the role of transient adaptive resistance by probing multidrug resistance (MDR) efflux pumps, ancient elements that are important for bacterial physiology and virulence. Accordingly, we constructed an efflux pump deficient mutant (∆mexF) and used resistance-nodulation-division (RND) efflux pump inhibitors (EPIs). While batch results showed the importance of RND efflux pumps for microbial survival, microfluidic studies indicated that these pumps were not necessary for survival in antibiotic gradients. Our work contributes to an emerging body of knowledge deciphering the effects of antibiotic spatial heterogeneity on microorganisms and highlights differences of microbial response in these systems versus well-mixed batch conditions.


Asunto(s)
Ciprofloxacina , Nitratos , Antibacterianos/farmacología , Proteínas Bacterianas , Quimiotaxis , Ciprofloxacina/farmacología , Farmacorresistencia Bacteriana Múltiple , Ecosistema , Proteínas de Transporte de Membrana , Pruebas de Sensibilidad Microbiana , Shewanella
16.
Sci Rep ; 11(1): 2230, 2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33500473

RESUMEN

The Scleractinian corals Orbicella annularis and O. faveolata have survived by acclimatizing to environmental changes in water depth and sea surface temperature (SST). However, the complex physiological mechanisms by which this is achieved remain only partially understood, limiting the accurate prediction of coral response to future climate change. This study quantitatively tracks spatial and temporal changes in Symbiodiniaceae and biomolecule (chromatophores, calmodulin, carbonic anhydrase and mucus) abundance that are essential to the processes of acclimatization and biomineralization. Decalcified tissues from intact healthy Orbicella biopsies, collected across water depths and seasonal SST changes on Curaçao, were analyzed with novel autofluorescence and immunofluorescence histology techniques that included the use of custom antibodies. O. annularis at 5 m water depth exhibited decreased Symbiodiniaceae and increased chromatophore abundances, while O. faveolata at 12 m water depth exhibited inverse relationships. Analysis of seasonal acclimatization of the O. faveolata holobiont in this study, combined with previous reports, suggests that biomolecules are differentially modulated during transition from cooler to warmer SST. Warmer SST was also accompanied by decreased mucus production and decreased Symbiodiniaceae abundance, which is compensated by increased photosynthetic activity enhanced calcification. These interacting processes have facilitated the remarkable resiliency of the corals through geological time.


Asunto(s)
Trastornos del Sueño-Vigilia/fisiopatología , Animales , Antozoos/fisiología , Cambio Climático , Dinoflagelados/fisiología , Femenino , Angiografía por Resonancia Magnética , Masculino , Fotosíntesis/fisiología
17.
Nat Rev Urol ; 18(7): 404-432, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-34031587

RESUMEN

GeoBioMed - a new transdisciplinary approach that integrates the fields of geology, biology and medicine - reveals that kidney stones composed of calcium-rich minerals precipitate from a continuum of repeated events of crystallization, dissolution and recrystallization that result from the same fundamental natural processes that have governed billions of years of biomineralization on Earth. This contextual change in our understanding of renal stone formation opens fundamentally new avenues of human kidney stone investigation that include analyses of crystalline structure and stratigraphy, diagenetic phase transitions, and paragenetic sequences across broad length scales from hundreds of nanometres to centimetres (five Powers of 10). This paradigm shift has also enabled the development of a new kidney stone classification scheme according to thermodynamic energetics and crystalline architecture. Evidence suggests that ≥50% of the total volume of individual stones have undergone repeated in vivo dissolution and recrystallization. Amorphous calcium phosphate and hydroxyapatite spherules coalesce to form planar concentric zoning and sector zones that indicate disequilibrium precipitation. In addition, calcium oxalate dihydrate and calcium oxalate monohydrate crystal aggregates exhibit high-frequency organic-matter-rich and mineral-rich nanolayering that is orders of magnitude higher than layering observed in analogous coral reef, Roman aqueduct, cave, deep subsurface and hot-spring deposits. This higher frequency nanolayering represents the unique microenvironment of the kidney in which potent crystallization promoters and inhibitors are working in opposition. These GeoBioMed insights identify previously unexplored strategies for development and testing of new clinical therapies for the prevention and treatment of kidney stones.


Asunto(s)
Biomineralización/fisiología , Cálculos Renales/química , Nefrolitiasis/metabolismo , Apatitas , Oxalato de Calcio , Fosfatos de Calcio , Cristalización , Durapatita , Fenómenos Geológicos , Humanos , Cálculos Renales/clasificación , Nefrolitiasis/fisiopatología , Transición de Fase
18.
Kidney360 ; 2(2): 298-311, 2021 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-35373025

RESUMEN

Background: Human kidney stones form via repeated events of mineral precipitation, partial dissolution, and reprecipitation, which are directly analogous to similar processes in other natural and manmade environments, where resident microbiomes strongly influence biomineralization. High-resolution microscopy and high-fidelity metagenomic (microscopy-to-omics) analyses, applicable to all forms of biomineralization, have been applied to assemble definitive evidence of in vivo microbiome entombment during urolithiasis. Methods: Stone fragments were collected from a randomly chosen cohort of 20 patients using standard percutaneous nephrolithotomy (PCNL). Fourier transform infrared (FTIR) spectroscopy indicated that 18 of these patients were calcium oxalate (CaOx) stone formers, whereas one patient formed each formed brushite and struvite stones. This apportionment is consistent with global stone mineralogy distributions. Stone fragments from seven of these 20 patients (five CaOx, one brushite, and one struvite) were thin sectioned and analyzed using brightfield (BF), polarization (POL), confocal, super-resolution autofluorescence (SRAF), and Raman techniques. DNA from remaining fragments, grouped according to each of the 20 patients, were analyzed with amplicon sequencing of 16S rRNA gene sequences (V1-V3, V3-V5) and internal transcribed spacer (ITS1, ITS2) regions. Results: Bulk-entombed DNA was sequenced from stone fragments in 11 of the 18 patients who formed CaOx stones, and the patients who formed brushite and struvite stones. These analyses confirmed the presence of an entombed low-diversity community of bacteria and fungi, including Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, and Aspergillus niger. Bacterial cells approximately 1 µm in diameter were also optically observed to be entombed and well preserved in amorphous hydroxyapatite spherules and fans of needle-like crystals of brushite and struvite. Conclusions: These results indicate a microbiome is entombed during in vivo CaOx stone formation. Similar processes are implied for brushite and struvite stones. This evidence lays the groundwork for future in vitro and in vivo experimentation to determine how the microbiome may actively and/or passively influence kidney stone biomineralization.


Asunto(s)
Oxalato de Calcio , Cálculos Renales , Bacterias/genética , Oxalato de Calcio/análisis , Fosfatos de Calcio , Hongos , Humanos , Cálculos Renales/química , ARN Ribosómico 16S , Estruvita
19.
Environ Sci Technol ; 44(20): 7833-8, 2010 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-20804136

RESUMEN

A microfluidic pore structure etched into a silicon wafer was used as a two-dimensional model subsurface sedimentary system (i.e., micromodel) to study mineral precipitation and permeability reduction relevant to groundwater remediation and geological carbon sequestration. Solutions containing CaCl(2) and Na(2)CO(3) at four different saturation states (Ω = [Ca(2+)][CO(3)(2-)]/K(spCaCO(3))) were introduced through two separate inlets, and they mixed by diffusion transverse to the main flow direction along the center of the micromodel resulting in CaCO(3) precipitation. Precipitation rates increased and the total amount of precipitates decreased with increasing saturation state, and only vaterite and calcite crystals were formed (no aragonite). The relative amount of vaterite increased from 80% at the lowest saturation state (Ω(v) = 2.8 for vaterite) to 95% at the highest saturation state (Ω(v) = 4.5). Fluorescent tracer tests conducted before and after CaCO(3) precipitation indicate that pore spaces were occluded by CaCO(3) precipitates along the transverse mixing zone, thus substantially reducing porosity and permeability, and potentially limiting transformation from vaterite to the more stable calcite. The results suggest that mineral precipitation along plume margins can decrease both reactant mixing during groundwater remediation, and injection and storage efficiency during CO(2) sequestration.


Asunto(s)
Carbonato de Calcio/química , Sedimentos Geológicos/química , Microscopía , Modelos Teóricos , Permeabilidad , Espectrometría Raman
20.
Artículo en Inglés | MEDLINE | ID: mdl-33344934

RESUMEN

Successful Scholar-Athletes are physically, intellectually, and emotionally committed to high-level achievement in both their academic and sport endeavors. This requires development of an integrated skill-set that includes teamwork, a strong work ethic, commitment, leadership, time management, and physical and emotional health. The identity crosses all perceived boundaries of race, gender, ethnicity, sexual orientation, religion, disability, social, and economic status. A nationwide paradigm shift is urgently needed to recognize and tap into these skills for all scholar-athletes, which are the same tools required to succeed in all professions from science and technology to law, medicine, business and the arts. This article addresses the misperceptions and low expectations that much of our society has for the high school and collegiate Scholar-Athlete. While recognizing the efforts of programs that are working to recalibrate the high school athlete's self perceptions, awaken recognition of their own academic potential, and permit them to achieve successful careers and make invaluable professional contributions to society.

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