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Cell Host & Microbe Jul 2022Acinetobacter baumannii is a leading cause of hospital-acquired infections, where outbreaks are driven by its ability to persist on surfaces in a desiccated state. Here,...
Acinetobacter baumannii is a leading cause of hospital-acquired infections, where outbreaks are driven by its ability to persist on surfaces in a desiccated state. Here, we show that A. baumannii causes more virulent pneumonia following desiccation and profile the genetic requirements for desiccation. We find that desiccation tolerance is enhanced upon the disruption of Lon protease, which targets unfolded and aggregated proteins for degradation. Notably, two bacterial hydrophilins, DtpA and DtpB, are transcriptionally upregulated in Δlon via the two-component regulator, BfmR. These proteins, both hydrophilic and intrinsically disordered, promote desiccation tolerance in A. baumannii. Additionally, recombinant DtpA protects purified enzymes from inactivation and improves the desiccation tolerance of a probiotic bacterium when heterologously expressed. These results demonstrate a connection between environmental persistence and pathogenicity in A. baumannii, provide insight into the mechanisms of extreme desiccation tolerance, and reveal potential applications for bacterial hydrophilins in the preservation of protein- and live bacteria-based pharmaceuticals.
Topics: Acinetobacter baumannii; Bacterial Proteins; Desiccation; Pentetic Acid; Virulence
PubMed: 35413266
DOI: 10.1016/j.chom.2022.03.019 -
Journal of Nuclear Medicine : Official... Jan 1976A source of error in cerebrospinal fluid (CSF) infusion tests is leakage at the dural puncture site. The addition of a bolus of radionuclide to the infusion fluid was...
A source of error in cerebrospinal fluid (CSF) infusion tests is leakage at the dural puncture site. The addition of a bolus of radionuclide to the infusion fluid was helpful in detecting the existence of leakage as shown by increased infusion pressure in six of eight patients studied with and without scintigraphic evidence of leakage. Comparison of CSF dynamics in 26 patients studied by infusion cisternography and conventional cisternography showed similar patterns, suggesting no alteration of CSF dynamics by the artificial CSF infusion. Combining the two tests, therefore, resulted in simple identification of the leakage and saved the patient time and discomfort.
Topics: Cisterna Magna; Humans; Hydrocephalus; Pentetic Acid; Radionuclide Imaging; Ytterbium
PubMed: 1244453
DOI: No ID Found -
Free Radical Biology & MedicineHydrogen sulfide (H₂S) is a ubiquitous gaseous signaling molecule that plays a vital role in numerous cellular functions and has become the focus of many research...
Hydrogen sulfide (H₂S) is a ubiquitous gaseous signaling molecule that plays a vital role in numerous cellular functions and has become the focus of many research endeavors, including pharmacotherapeutic manipulation. Among the challenges facing the field is the accurate measurement of biologically active H₂S. We have recently reported that the typically used methylene blue method and its associated results are invalid and do not measure bona fide H₂S. The complexity of analytical H₂S measurement reflects the fact that hydrogen sulfide is a volatile gas and exists in the body in various forms, including a free form, an acid-labile pool, and bound as sulfane sulfur. Here we describe a new protocol to discretely measure specific H₂S pools using the monobromobimane method coupled with RP-HPLC. This new protocol involves selective liberation, trapping, and derivatization of H₂S. Acid-labile H₂S is released by incubating the sample in an acidic solution (pH 2.6) of 100 mM phosphate buffer with 0.1mM diethylenetriaminepentaacetic acid (DTPA), in an enclosed system to contain volatilized H₂S. Volatilized H₂S is then trapped in 100 mM Tris-HCl (pH 9.5, 0.1 mM DTPA) and then reacted with excess monobromobimane. In a separate aliquot, the contribution of the bound sulfane sulfur pool was measured by incubating the sample with 1 mM TCEP (tris(2-carboxyethyl)phosphine hydrochloride), a reducing agent, to reduce disulfide bonds, in 100 mM phosphate buffer (pH 2.6, 0.1 mM DTPA), and H₂S measurement was performed in a manner analogous to the one described above. The acid-labile pool was determined by subtracting the free hydrogen sulfide value from the value obtained by the acid-liberation protocol. The bound sulfane sulfur pool was determined by subtracting the H₂S measurement from the acid-liberation protocol alone compared to that of TCEP plus acidic conditions. In summary, our new method allows very sensitive and accurate measurement of the three primary biological pools of H₂S, including free, acid-labile, and bound sulfane sulfur, in various biological specimens.
Topics: Adult; Animals; Bridged Bicyclo Compounds; Chemistry Techniques, Analytical; Chromatography, High Pressure Liquid; Humans; Hydrogen Sulfide; Male; Pentetic Acid; Phosphines; Sulfides; Volatilization; Young Adult
PubMed: 22561703
DOI: 10.1016/j.freeradbiomed.2012.04.007 -
International Journal of Molecular... Dec 2020is a valuable hardwood plant with a high economical value for its medicinal and ornamental qualities. The aim of this work was to investigate the effects of the iron...
is a valuable hardwood plant with a high economical value for its medicinal and ornamental qualities. The aim of this work was to investigate the effects of the iron (Fe) source and medium pH on the growth and development of in vitro. The Fe sources used, including non-chelated iron sulfate (FeSO), iron ethylenediaminetetraacetic acid (Fe-EDTA), and iron diethylenetriaminepentaacetic acid (Fe-DTPA), were supplemented to the Multipurpose medium with a final Fe concentration of 2.78 mg·L. The medium without any supplementary Fe was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70. The experiment was conducted in a culture room for six weeks with 25 °C day and night temperatures, and a 16-h photoperiod with a light intensity of 50 mmol·m·s photosynthetic photon flux density (PPFD). Both the Fe source and pH affected the growth and development of the micropropagated plants in vitro. The leaves were greener in the pH 4.70 and 5.70 treatments. The tissue Fe content decreased with the increase of the medium pH. The leaf chlorophyll content was similar between plants treated with FeSO and those with Fe-EDTA. The numbers of the shoots and roots of plantlets treated with FeSO were 2.5 and 2 times greater than those of the control, respectively. The fresh and dry weights of the shoot and the root were the greatest for plants treated with Fe-EDTA combined with pH 5.70. The calcium, magnesium, and manganese contents in the plantlets increased in the pH 5.70 treatments regardless of the Fe source. Supplementary Fe decreased the activity of ferric chelate reductase. Overall, although the plantlets absorbed more Fe at pH 4.70, Fe-EDTA combined with pH 5.70 was found to be the best for the growth and development of in vitro.
Topics: Antioxidants; Chlorophyll; Culture Media; Edetic Acid; FMN Reductase; Ferric Compounds; Ferrous Compounds; Hydrogen-Ion Concentration; Iron; Pentetic Acid; Photosynthesis; Plant Leaves; Plant Roots; Plant Stomata; Sorbus; Time Factors
PubMed: 33374479
DOI: 10.3390/ijms22010133 -
Radiation and Environmental Biophysics Nov 2023A major challenge in modelling the decorporation of actinides (An), such as americium (Am), with DTPA (diethylenetriaminepentaacetic acid) is the fact that standard...
A major challenge in modelling the decorporation of actinides (An), such as americium (Am), with DTPA (diethylenetriaminepentaacetic acid) is the fact that standard biokinetic models become inadequate for assessing radionuclide intake and estimating the resulting dose, as DTPA perturbs the regular biokinetics of the radionuclide. At present, most attempts existing in the literature are empirical and developed mainly for the interpretation of one or a limited number of specific incorporation cases. Recently, several approaches have been presented with the aim of developing a generic model, one of which reported the unperturbed biokinetics of plutonium (Pu), the chelation process and the behaviour of the chelated compound An-DTPA with a single model structure. The aim of the approach described in this present work is the development of a generic model that is able to describe the biokinetics of Am, DTPA and the chelate Am-DTPA simultaneously. Since accidental intakes in humans present many unknowns and large uncertainties, data from controlled studies in animals were used. In these studies, different amounts of DTPA were administered at different times after contamination with known quantities of Am. To account for the enhancement of faecal excretion and reduction in liver retention, DTPA is assumed to chelate Am not only in extracellular fluids, but also in hepatocytes. A good agreement was found between the predictions of the proposed model and the experimental results for urinary and faecal excretion and accumulation and retention in the liver. However, the decorporation from the skeletal compartment could not be reproduced satisfactorily under these simple assumptions.
Topics: Humans; Rats; Animals; Pentetic Acid; Americium; Models, Biological; Chelating Agents; Plutonium
PubMed: 37831188
DOI: 10.1007/s00411-023-01046-z -
The Western Journal of Medicine Jan 1988Smoke inhalation causes most of the deaths in fire-related injuries, with pulmonary edema as a major determinant in the outcome of smoke-inhalation injury. The... (Review)
Review
Smoke inhalation causes most of the deaths in fire-related injuries, with pulmonary edema as a major determinant in the outcome of smoke-inhalation injury. The pathophysiology of pulmonary edema is thought to be related to the products of incomplete combustion. Damage to the integrity of the alveolar epithelium is one of the determinants of the development of smoke-induced pulmonary edema. In recent studies using lung clearance of aerosolized pentetic acid (DTPA [diethylenetriaminepentaacetic acid]) labeled with technetium Tc 99m to assess the permeability of the alveolar epithelium, several factors were identified that may increase a person's susceptibility to smoke-induced acute lung injury. These are increased initial alveolar permeability and alterations in the number and activity of alveolar macrophages. Clinical measurement of (99m)TcDTPA clearance may provide a sensitive and convenient method for the early detection and serial assessment of smoke-induced alveolar epithelial permeability changes.
Topics: Animals; Burns, Inhalation; Humans; Organometallic Compounds; Pentetic Acid; Pulmonary Edema; Rabbits; Technetium Tc 99m Pentetate
PubMed: 3277334
DOI: No ID Found -
Regulatory Toxicology and Pharmacology... Aug 2018Aminocarboxylic acid (ethylenediamine-based) chelating agents, such as DTPA and EDTA, are widely used in a variety of products and processes. Recently the European RAC... (Review)
Review
Aminocarboxylic acid (ethylenediamine-based) chelating agents, such as DTPA and EDTA, are widely used in a variety of products and processes. Recently the European RAC proposed to classify DTPA as a developmental toxicant Category 1B according to CLP. This paper provides unequivocal and significant evidence that developmental effects cannot be considered an intrinsic property of the chelating substances themselves since: (1) animals fed a zinc deficient diet during gestation exhibit developmental toxicity of a similar nature and severity to that observed in studies involving such chelates, (2) sufficient supplementation of zinc in the diet, or administration of zinc bound chelates, completely negates the developmental effects. Moreover, the bioavailability of DTPA is very low with >95% of oral doses excreted unchanged via the feces within 24 h. If DTPA would possess the intrinsic property to be developmentally toxic, simple zinc supplementation should not be sufficient to negate these effects. Furthermore, the relevance of classification is highly questionable since worker or consumer exposure could not lead to a scenario whereby sufficient zinc deficiency would manifest itself. Therefore classification of DTPA for such effects is not protective of human health; instead it leads to onerous and disproportionate restrictions being placed on this substance.
Topics: Animals; Chelating Agents; Humans; Pentetic Acid; Zinc
PubMed: 29964121
DOI: 10.1016/j.yrtph.2018.06.019 -
International Journal of Environmental... Apr 2019Chelators including DTPA (diethylene triamine pentaacetic acid) and oxalic acid were selected for inducing phytoextraction of heavy metals (HMs) from Pb-, Tl-, and...
Chelators including DTPA (diethylene triamine pentaacetic acid) and oxalic acid were selected for inducing phytoextraction of heavy metals (HMs) from Pb-, Tl-, and Pb-Tl- contaminated soil, in which heavy metals leakage was highly remarkable. Results showed that compared with the control group without chelating agent under planting conditions, the extraction efficiency (i.e., uptake coefficient) of Pb, Tl increased by 86%, 43% from Pb-Tl- contaminated soil in the presence of oxalic acid, and there was no significant change in heavy metal leakage under rainfall conditions. It was the best phytoremediation scheme in this work. Under rainfall conditions, the HMs concentration in the leachate showed a linear decreasing trend. Acid rain promoted the leakage of heavy metals, and the average leached amount of Tl increased by 1.47 times under acid rain conditions. However, for Pb, DTPA was the main influencing factor, followed by acid rain.
Topics: Biodegradation, Environmental; Chelating Agents; Lead; Oxalic Acid; Pentetic Acid; Soil; Soil Pollutants; Thallium
PubMed: 31013864
DOI: 10.3390/ijerph16081328 -
Angiogenesis Jun 2010During the early stages of angiogenesis, following stimulation of endothelial cells by vascular endothelial growth factor (VEGF), the vascular wall is breached, allowing... (Review)
Review
During the early stages of angiogenesis, following stimulation of endothelial cells by vascular endothelial growth factor (VEGF), the vascular wall is breached, allowing high molecular weight proteins to leak from the vessels to the interstitial space. This hallmark of angiogenesis results in deposition of a provisional matrix, elevation of the interstitial pressure and induction of interstitial convection. Albumin, the major plasma protein appears to be an innocent bystander that is significantly affected by these changes, and thus can be used as a biomarker for vascular permeability associated with angiogenesis. Traditionally, albumin leak in superficial organs was followed by colorimetry or morphometry with the use of albumin binding vital dyes. Over the last years, the introduction of tagged-albumin that can be detected by various imaging methods, such as magnetic resonance imaging and positron emission tomography, opened new possibilities for quantitative three dimension dynamic analysis of permeability in any organ. Using these tools it is now possible to follow not only vascular permeability, but also interstitial convection and lymphatic drain. Active uptake of tagged albumin by caveolae-mediated endocytosis opens the possibility for using labeled albumin for vital staining of cells and cell tracking. This approach was used for monitoring recruitment of perivascular stroma fibroblasts associated with tumor angiogenesis.
Topics: Animals; Biotin; Capillary Permeability; Diagnostic Imaging; Humans; Lymphatic System; Pentetic Acid; Serum Albumin; Serum Albumin, Bovine; Staining and Labeling
PubMed: 20512410
DOI: 10.1007/s10456-010-9170-4 -
Journal of Medicinal Chemistry Apr 2022This study aims to establish new labeling methods for no-carrier-added radio-Pt (Pt) and to evaluate the in vitro properties of Pt-labeled agents compared with those of...
This study aims to establish new labeling methods for no-carrier-added radio-Pt (Pt) and to evaluate the in vitro properties of Pt-labeled agents compared with those of agents labeled with the common emitter In. Pt was complexed with the DNA-targeting dye Hoechst33258 via diethylenetriaminepentaacetic acid (DTPA) or the sulfur-containing amino acid cysteine (Cys). The intranuclear fractions of Pt- and In-labeled Hoechst33258 were comparable, indicating that the labeling for Pt via DTPA or Cys and the labeling for In via DTPA worked equally well. Pt showed a DNA-binding/cellular uptake ratio of more than 1 order of magnitude greater than that of In. [Pt]Pt-Hoechst33258 labeled via Cys showed a higher cellular uptake than that labeled via DTPA, resulting in a very high DNA-binding fraction of [Pt]Pt-Cys-Hoechst33258 and extensive DNA damage. Our labeling methods of radio-Pt, especially via Cys, promote the development of radio-Pt-based agents for use in Auger electron therapy targeting DNA.
Topics: Cysteine; DNA; Electrons; Pentetic Acid
PubMed: 35358392
DOI: 10.1021/acs.jmedchem.1c02209