Gluconacetobacter xylinus possesses a constitutive membrane-bound oxidase system for the use of ethanol. Its alcohol dehydrogenase complex (ADH) was purified to homogeneity and characterized. It is a ...119-kDa heterodimer (68 and 41 kDa subunits). The peroxidase reaction confirmed the presence of haem C in both subunits. Four cytochromes c per enzyme were determined by pyridine hemochrome spectroscopy. Redox titrations of the purified ADH revealed the presence of four haem c redox centers, with apparent mid-point potential values (Em₇) of −33, +55, +132 and +310 mV, respectively. The ADH complex contains one mol of pyrroloquinoline quinone as determined by HPLC. The enzyme was purified in full reduced state; oxidation was induced by potassium ferricyanide and substrate restores full reduction. Activity responses to pH were sharp, showing two distinct optimal pH values (i.e. pH 5.5 and 6.5) depending on the electron acceptor used. Purified ADH oxidizes primary alcohols (C2-C6) but not methanol. Noteworthy, aliphatic aldehydes (C1-C4) were also good substrates. Myxothiazol and antymicin A were powerful inhibitors of the purified ADH complex, most likely acting at the ubiquinone acceptor site in subunit II.
BACKGROUND: Screening for active TB using active case-finding (ACF) may reduce TB incidence, prevalence, and mortality; however, yield of ACF interventions varies substantially across populations. We ...systematically reviewed studies reporting on ACF to calculate the number needed
to screen (NNS) for groups at high risk for TB.METHODS: We conducted a literature search for studies reporting ACF for adults published between November 2010 and February 2020. We determined active TB prevalence detected through various screening strategies and calculated crude
NNS for - TB confirmed using culture or Xpert® MTB/RIF, and weighted mean NNS stratified by screening strategy, risk group, and country-level TB incidence.RESULTS: We screened 27,223 abstracts; 90 studies were included (41 in low/moderate and 49 in medium/high TB
incidence settings). High-risk groups included inpatients, outpatients, people living with diabetes (PLWD), migrants, prison inmates, persons experiencing homelessness (PEH), healthcare workers, and miners. Screening strategies included symptom-based screening, chest X-ray and Xpert testing.
NNS varied widely across and within incidence settings based on risk groups and screening methods. Screening tools with higher sensitivity (e.g., Xpert, CXR) were associated with lower NNS estimates.CONCLUSIONS: NNS for ACF strategies varies substantially between adult risk groups.
Specific interventions should be tailored based on local epidemiology and costs.
Abstract Lyme disease (LD), caused by Borrelia burgdorferi, is the most common vector-borne disease in the United States and Europe. Despite the standard 2–4 weeks' antibiotic treatment, ...approximately 10%–20% of patients will develop posttreatment LD syndrome, a condition that is poorly understood. One of the probable causes is thought to be the presence of B. burgdorferi persister forms that are not effectively killed by the current LD antibiotics. In this study, we evaluated nitroxoline, an antibiotic used to treat urinary tract infections, for its activity against a stationary-phase culture enriched with persister forms of B. burgdorferi . Nitroxoline was found to be more active than doxycycline and equally active as cefuroxime (standard LD antibiotics) against B. burgdorferi . Importantly, the nitroxoline two-drug combinations nitroxoline + cefuroxime and nitroxoline + clarithromycin, as well as the nitroxoline three-drug combination nitroxoline + cefuroxime + clarithromycin, were as effective as the persister drug daptomycin-based positive control three-drug combination cefuroxime + doxycycline + daptomycin, completely eradicating stationary-phase B. burgdorferi in the drug-exposure experiments and preventing regrowth in the subculture study. Future studies should evaluate these promising drug combinations in a persistent LD mouse model.
BACKGROUND: Systematic screening for active TB is recommended for all people living with HIV (PLWH); however, case detection remains poor globally. We investigated the yield of active case finding ...(ACF) by calculating the number needed to screen (NNS) to detect a case of active
TB among PLWH.METHODS: We identified studies reporting ACF for TB among PLWH published from November 2010 to February 2020. We calculated crude NNS for Xpert- or culture-confirmed TB and weighted mean NNS stratified by screening approach, population/risk group, and country TB burden.RESULTS:
Of the 27,221 abstracts screened, we identified 58 studies eligible for inclusion, including 5 in low/moderate TB incidence settings and 53 in medium/high incidence settings. Populations screened for TB included inpatients, outpatients not receiving antiretroviral therapy (ART), outpatients
receiving ART, those with CD4 < 200 cells/µL, children aged ≤15 years, pregnant PLWH, and PLWH in prisons. Screening tools included symptom-based screening, chest X-ray, C-reactive protein levels, and Xpert. The weighted mean NNS varied across groups but was consistently low, ranging
from 4 among inpatients in moderate/high TB burden settings to 137 among pregnant PLWH in moderate/high TB burden settings.CONCLUSIONS: ACF is a high yield intervention among PLWH. Approaches to screening should be tailored to local epidemiological and health-system contexts, and
sensitive screening tools such as Xpert should be implemented where feasible.
Aims: Gluconacetobacter xylinum is well known for its ability to produce large amounts of cellulose, however, little is known about its cell physiology. Our goal was to study the respiratory ...metabolism and components of the respiratory system of this bacterium in static cultures. To reach our goal, a medium formulation had to be designed to improve cell growth and cellulose production together with a novel method for the recovery of cells from cellulose pellicles.
Methods and Results: Successive modifications of a nutrient medium improved G. xylinum cell growth 4·5‐fold under static culture conditions. A blender homogenization procedure for the releasing of cells from the cellulose matrix gave a high yield of cells recovered. Respiratory activities of purified cells were greatly stimulated by exogenous substrates and showed to be resistant to KCN. Unexpectedly, exogenous NADH was oxidized at high rates. Cytochromes a, b, c and d were identified after spectral analyses.
Conclusions: Partial bioenergetic characterization of G. xylinum cells allowed us to propose a scheme for its respiratory system. In addition, the growth medium for biomass production and the procedure for the efficient recovery of cells from cellulose pellicles were significantly improved.
Significance and Impact of the Study: This work provides the first‐ever bioenergetic characterization of G. xylinum grown in static cultures. In addition, a novel methodology to obtain purified cells in suitable quantities for biochemical research is described.
Considering the potential applications of cadmium oxide (CdO) thin films in optoelectronics, this work aims to investigate the structural, optical, compositional, and morphological properties of CdO ...thin films obtained by converting CdCO3 thin films into CdO by thermal annealing. The established method consists of thermal treatment for 2 h at different temperatures for CdO thin film obtention. The CdO thin films were characterized by ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TGA). The direct band gap of the CdO thin films obtained was 2.39 and 2.43 eV. These values are in the range reported in the literature for CdO thin films and are related to direct transitions of electrons between valence and conduction bands. Furthermore, the HR-TEM and XRD analysis confirmed a cubic crystalline structure for CdO thin films. The low-resolution and high-resolution XPS spectra further confirm the expected chemical composition of CdO thin films.
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•Successfully obtention of CdO thin films by head treated CdCO3 thin films.•Optical bandgap by Tauc Method and d(lnα)d(hν) confirm a direct bandgap of 2.39 eV.•High resolution XPS spectra confirm the chemical state and bonding energy of the CdO thin films.•The CdO thin films have a cubic polycrystalline structure confirmed by XRD and HR-TEM techniques.
We studied whether mitochondrial functions and Ca2+ metabolism were altered in Wistar Kyoto normotensive (WKY) and spontaneous hypertensive rats (SHR). Ca2+ uptake was decreased in SHR compared to ...WKY rats. Accumulation of Ca2+ was more efficient in WKY than in SHR rats. mDeltaPsi was lower in SHR compared to WKY rats. Basal complex IV activity was higher in SHR than WKY rats, whereas basal L-citrulline production, an indicator of nitric oxide synthesis, was decreased in SHR and dependent on Ca2+ concentration (p<0.05). Impact of Ca2+ was counteracted by EGTA. These data show an age-dependent decreased mitochondrial functions in brain mitochondria during hypertension.
The purpose of this paper is establishing two stables and originals formulations routes for the synthesis of cadmium carbonate (CdCO3) by chemical bath deposition (CBD) and the analysis of the ...physical properties of the synthesized materials, such as optical, chemical, structural and morphological properties by using characterization techniques such as optical absorption by diffuse reflectance, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning electron microscopy (SEM) and Raman. The direct bandgaps values related to direct transitions of electrons from the valence band to the conduction band of CdCO3 thin films are 3.81 and 3.79 eV. By X-ray diffraction (XRD) technique was determined as a hexagonal structure with space group R-3c (167) for CdCO3 thin films. Finally, the expected chemical composition of CdCO3 thin films was proving by the low- and high-resolution X-ray Photoelectron Spectroscopy (XPS) spectra. The Raman spectra show five vibrational characteristics frequencies of CdCO3 and evidencing that the synthesized thin films correspond to CdCO3.
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•Successfully obtention of two originals formulations for CdCO3 thin films synthesized by CBD method.•Optical and XRD results indicate a direct bandgap of 3.81 and 3.79 eV, and a hexagonal polycrystalline structure for CdCO3 thin films.•The morphological study revealed rods and spherical agglomerated formations of 10 and 1 μm, respectively.•High definition XPS spectra confirm the chemical composition of the CdCO3 thin films-.•The Raman spectra confirm the composition of CdCO3 thin films by five vibrational characteristical frequencies of CdCO3.
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