Polarized Raman spectroscopy was used to analyze aqueous solutions of sodium orthophosphate and orthovanadate over a wide concentration range (0.00891–0.702 mol/L) at 23 °C. The isotropic scattering profiles were obtained by measuring polarized Raman scattering spectra. Furthermore, R-normalized spectra were calculated and presented. The tetrahedral ions, VO43–(aq) and PO43–(aq), demand four Raman active bands which have been subsequently characterized and assigned. For the PO43–(aq) ion, the deformation modes ν2(e) and ν4(f2) appear at 415 and 557 cm–1, and these modes are depolarized. In the P–O stretching region, the strongest Raman band appears at 936.5 cm–1, which is totally polarized with a depolarization ratio (ρ-value) of 0.002. The broad and depolarized mode at 1010 cm–1 constitutes the antisymmetric stretching band ν3(f2). The Raman spectrum of VO43– shows two depolarized deformation modes ν2(e) and ν4(f2) at 327 and 345.6 cm–1, which are severely overlapped. These bands are very weak. The strongest band in the Raman spectrum of VO43–(aq) is the symmetric stretching mode ν1(a1) at 820.2 cm–1 which is totally polarized with a ρ-value at 0.004. The depolarized antisymmetric stretching mode ν3(f2) appeared at 785 cm–1 as a broad and weak band. Both anions are strongly hydrated and showed extensive hydrolysis in an aqueous solution. Orthovanadate is a much stronger base than orthophosphate in aqueous solution. Therefore, a large amount of NaOH was used to suppress the hydrolysis of VO43–(aq) sufficiently, so, it was possible to characterize the VO43– modes. Quantitative Raman spectroscopy was applied to follow the hydrolysis of PO43– over a wide concentration range from 0.00891 to 0.592 mol/L. The hydrolysis data allowed the calculation of the p Ka3 value for H3PO4 to be 12.330 ± 0.02 (25 °C). The hydrolysis of the VO43– ion is ∼21 times larger than that of the PO43–. The p Ka3 value for H3VO4 is estimated to be 13.65 ± 0.1 (25 °C).
Recent publications indicate that A. radioresistens can cause infections in humans, even though it is rarely reported in routine diagnostics. However, the fact that it is infrequently detected may be explained by the misidentification of the species by conventional methods. It is also likely that A. radioresistens is not considered clinically relevant and therefore not consistently included in diagnostic results. To elucidate the medical significance of this probably clinically underestimated bacterial species, we created a well-documented reference strain collection of 21 strains collected in routine diagnostics. For further analysis of A. radioresistens, it is essential to know which methods can be used to achieve a trustworthy identification. We, therefore, compared three methods widely used in routine diagnostics (MALDI-TOF MS, VITEK 2, and sequencing of housekeeping genes) in terms of secure and reliable identification of A. radioresistens. As reference methods, whole genome-based approaches were applied. VITEK 2 led to misidentification for four strains. However, MALDI-TOF MS and sequencing of housekeeping genes led to reliable and robust identifications.
NaHCOO(aq) and NaDCOO(aq) solutions were measured using Raman spectroscopy from dilute to concentrated solutions at 23 °C in water and heavy water from 50 to 4300 cm−1. A concentrated NaHCOO solution in heavy water was also measured. The Raman band parameters of HCOO−(aq) and DCOO−(aq) such as peak position, full width at half maximum (fwhm), integrated intensities, and depolarization values were determined. From the Raman spectroscopic data, it was concluded that the HCOO−(aq) and DCOO−(aq) symmetry is lower than C2v and probably as low as C1. In contrast to the solution state, $$\tt \normalsize \tt \normalsize {\text{HCO}}_{2}^{ - }$$ ( $$\tt \normalsize\tt\normalsize {\text{DCO}}_{2}^{ - }$$ ) possess C2v symmetry in the gas phase and the DFT frequencies are given. DFT frequencies on a cluster of HCOO−/DCOO− with five implicit water molecules in the first sphere and placed in a polarizable continuum deviate not more than 1–2% from the measured ones. In the Raman spectrum in NaHCOO(aq), a band doublet at 2730 cm−1 and 2820 cm−1 occurs instead of a single band. The band doublet is due to Fermi resonance and results from the interaction of the overtone of the bending C–H mode, 2ν6 at 1382 cm−1 and ν1. The undisturbed C–H stretching mode, ν1 amounts to 2785 cm−1. In DCOO−(aq), a Fermi doublet was also observed at 2030.5 and 2116.5 cm−1, and the undisturbed wavenumber position amounts to 2101 cm−1. Furthermore, a solution of HCOO− in D2O showed slightly changed frequencies compared with the ones in water caused by the solvent isotope effect. Ion pairing between Na+ and HCOO− characterizes the Raman spectrum at high solute concentrations which are melt-like enabling direct contact between the ions. A NaHCOO solution with high amounts of LiCl added showed large perturbations of the HCOO− bands especially νsCOO− and δ COO− of HCOO−and revealed a stronger affinity of Li+ toward HCOO−. The ion pairs formed are most likely contact ion pairs between Li+ and HCOO− which have different stoichiometry of Li+: HCOO− such as 1:1 and 2:1.
Qualitative and quantitative Raman and infrared measurements on sodium nitrate (NaNO 3 ) solutions have been carried out over a wide concentration range (5.56 × 10 –6 –7.946 mol/L) in water and heavy water. The Raman spectra were measured from 4000 cm –1 to low wavenumbers at 45 cm –1 . Band fit analysis on the profile of the 1047 cm –1 band, ν 1 (a[Formula: see text]) [Formula: see text] measured at high resolution at 0.90 cm –1 produced a small contribution at 1027 cm –1 of the isotopomer N 16 O 2 18 O(aq). The effect of solute concentration on the Raman and infrared bands has been systematically recorded. Extrapolation of the experimental data resulted in values for all the nitrate bands of the “free”, i.e., fully hydrated [Formula: see text](aq). However, even in dilute solutions, the vibrational symmetry of the hydrated [Formula: see text](aq) is broken and the antisymmetric N–O stretch, which is degenerate for the isolated anion, is split by 56 cm –1 . At concentrations >2.5 mol/L, direct contact between Na + and [Formula: see text] was observed and accompanied by large band parameter changes. DFT calculations on [Formula: see text](H 2 O) n ( n = 1–3) led to optimized geometries and vibrational frequencies which reproduced the measured ones within an accuracy of 1%. A hydrated gas phase species Na + (H 2 O) 10 [Formula: see text] was optimized resulting in the geometry and symmetry of the nitrate, which is bound in an antisymmetric bidentate fashion with the nitrate possessing C 1 . The ν 1 Na + (OH 2 ) breathing mode in aqueous solution appears at 189 cm −1 , whereas in heavy water, ν 1 Na + (OD 2 ) is shifted to 175.6 cm –1 due to the isotope effect. DFT calculations on hydrated Na + (OH 2 ) n gas phase clusters provided realistic Na + hydrate structures with n = 4 and 5, which resembled the measured frequency of ν 1 Na + OH 2 mode quite well. Quantitative Raman analysis employing the symmetric stretching band, ν 1 (a[Formula: see text]) [Formula: see text], has been carried out down to concentrations as low as 5.56 × 10 –6 mol/L. The in-plane deformation mode ν 4 (e′) in the Raman scattering at higher concentrations has been used as an indicator band for directly coordinated [Formula: see text].
The totally symmetric stretching mode $$\nu_{1}$$ Ln–(OH2) of the first hydration shells of all the rare earth (RE) ions across the series from lanthanum to lutetium has been measured on dilute aqueous perchlorate solutions at room temperature. An S-shaped relationship has been found between the $$\nu_{1}$$ Ln–(OH2) peak positions and the Ln–(OH2) bond distances of the lanthanide(III) aqua ions. While the light rare earth ions form nona-hydrates, the heavy ones form octa-hydrates and the rare earth ions in the middle of the series show non integer hydration numbers between 9 and 8. A relationship between wavenumber positions $$\nu_{1}$$ Ln–(OH2) and the Ln–(OH2) bond distances of the RE hydrates has been given. Recent quantum mechanical calculations support the given interpretation.
We report a case of a 58-year-old male patient who underwent several surgeries following an accident. The bacterium Robinsoniella peoriensis was detected independently in multiple samples from both the right talus and tibia. The bacterium could only be identified using 16S rRNA gene sequencing.
The bacterial species Roseomonas mucosa is pathogenic in humans, and although it is rarely detected during routine diagnostics, it is becoming increasingly important clinically. For a long time, R. mucosa was regarded as a classic environmental bacterium. Recent studies, however, revealed that it is part of the physiological human skin flora and mainly affects immunocompromised patients. Furthermore, the use of catheter systems may increase the risk of contracting R. mucosa infections. The bacterium has been linked to severe infections, such as bacteraemia, osteomyelitis and cellulitis. Therefore, it is important to discern the best method of identifying R. mucosa in routine laboratory testing. To facilitate this testing, we compared three suitable methods for routine bacterial identification in the laboratory: VITEK 2, MALDI-TOF MS and 16S rRNA gene sequencing. Additionally, we conducted whole-genome sequencing (WGS) and calculated the average nucleotide identity (ANI). ANI is seen as the gold standard of strain identification; therefore, we decided to use it as a reference method. Both MALDI-TOF MS and 16S rRNA gene sequencing confidently identified the species. However, when using the VITEK 2 technique, isolates were misidentified as Roseomonas gilardii, Rhizobium radiobacter, or Sphingomonas paucimobilis. When conducting WGS and determining the ANI, it became obvious that one isolate belonged to the species R. gilardii rather than R. mucosa. Therefore (although not yet applicable in routine diagnostics), we suggest that WGS is presently the most appropriate technique to reliably identify Roseomonas mucosa. However, after expanding the Biotyper database, MALDI-TOF MS could also be an applicable method.
Raman spectra of aqueous Ho3+, Er3+, Tm3+, Yb3+, and Lu3+-perchlorate solutions were measured over a large wavenumber range from 50–4180 cm−1. In the low wavenumber range (terahertz region), strongly polarized Raman bands were detected at 387 cm−1, 389 cm−1, 391 cm−1, 394 cm−1, and 396 cm−1, respectively, which are fairly broad (full widths at half height at ~52 cm−1). These isotropic Raman bands were assigned to the breathing modes, ν1 Ln–O of the heavy rare earth (HRE) octaaqua ions, [Ln(H2O)8]3+. The strong polarization of these bands (depolarization degree ~0) reveals their totally symmetric character. The vibrational isotope effect was measured in Yb(ClO4)3 solutions in H2O and D2O and the shift of the ν1 mode in changing from H2O to D2O further supports the character of the band. The Ln–O bond distances of these HRE ions (Ho3+, Er3+, Tm3+, Yb3+, and Lu3+) follow the order of Ho–O > Er–O > Tm–O > Yb–O > Lu–O which correlates inversely with the band positions of the breathing modes of their corresponding octaaqua ions [Ln(OH2)8]3+. Furthermore, the force constants, kLn–O, were calculated for these symmetric stretching modes. Ytterbium perchlorate solutions were measured over a broad concentration range, from 0.240 mol·L−1 to 2.423 mol·L−1, and it was shown that with increasing solute concentration outer-sphere ion pairs and contact ion pairs were formed. At the dilute solution state (~0.3 mol·L−1), the fully hydrated ions [Yb(H2O)8]3+ exist, while at higher concentrations (CT > 2 mol·L−1), ion pairs are formed. The concentration behavior of Yb(ClO4)3 (aq) shows similar behavior to the one observed for La(ClO4)3(aq), Ce(ClO4)3(aq) and Lu(ClO4)3(aq) solutions. In ytterbium chloride solutions in water and heavy water, representative for the behavior of the other HRE ions, 1:1 chloro-complex formation was detected over the concentration range from 0.422–3.224 mol·L−1. The 1:1 chloro-complex in YbCl3(aq) is very weak, diminishing rapidly with dilution and vanishing at a concentration < 0.4 mol·L−1.
The genus Myroides comprises several species of Gram-negative, non-motile, and non-fermenting bacteria, which have been regarded as non-pathogenic for decades. Multiple recent reports, however, underscore the pathogenic potential that Myroides sp. possesses for humans. These bacteria seem to be resistant to a wide range of antibiotics (including ß-lactams and aminoglycosides). Therefore, treatment options are limited. Knowledge of antimicrobial resistance, however, is based on only one meaningful comprehensive study and on data published from case reports. This lack of data motivated us to test 59 strains from our Myroides collection (43 M. odoratimimus and 16 M. odoratus) for resistance against 20 commonly used antibiotics. We also performed molecular analyses to reveal whether our bacteria harbor the genus-specific M. odoratimimus metallo-ß-lactamase (MUS-1) or the M. odoratus metallo ß-lactamase (TUS-1), and other ß-lactamases, which may provide an explanation for the extended antimicrobial resistance.
Diarrhea-positive hemolytic-uremic syndrome (HUS) is a renal disorder that results from infections with Shiga-toxin (Stx)-producing Escherichia coli. The aim of this study was to establish well-defined refined murine models of HUS that can serve as preclinical tools to elucidate molecular mechanisms of disease development. C57BL/6J mice were subjected to different doses of Stx2 purified from an E. coli O157:H7 patient isolate. Animals received 300 ng/kg Stx2 and were sacrificed on day 3 to establish an acute model with fast disease progression. Alternatively, mice received 25 ng/kg Stx2 on days 0, 3, and 6, and were sacrificed on day 7 to establish a subacute model with moderate disease progression. Indicated by a rise in hematocrit, we observed dehydration despite volume substitution in both models, which was less pronounced in mice that underwent the 7-day regime. Compared with sham-treated animals, mice subjected to Stx2 developed profound weight loss, kidney dysfunction (elevation of plasma urea, creatinine, and neutrophil gelatinase-associated lipocalin), kidney injury (tubular injury and loss of endothelial cells), thrombotic microangiopathy (arteriolar microthrombi), and hemolysis (elevation of plasma bilirubin, lactate dehydrogenase, and free hemoglobin). The degree of complement activation (C3c deposition), immune cell invasion (macrophages and T lymphocytes), apoptosis, and proliferation were significantly increased in kidneys of mice subjected to the 7-day but not in kidneys of mice subjected to the 3-day regime. However, glomerular and kidney volume remained mainly unchanged, as assessed by 3D analysis of whole mount kidneys using CD31 staining with light sheet fluorescence microscopy. Gene expression analysis of kidneys revealed a total of only 91 overlapping genes altered in both Stx2 models. In conclusion, we have developed two refined mouse models with different disease progression, both leading to hemolysis, thrombotic microangiopathy, and acute kidney dysfunction and damage as key clinical features of human HUS. While intrarenal changes (apoptosis, proliferation, complement deposition, and immune cell invasion) mainly contribute to the pathophysiology of the subacute model, prerenal pathomechanisms (hypovolemia) play a predominant role in the acute model. Both models allow the further study of the pathomechanisms of most aspects of human HUS and the testing of distinct novel treatment strategies.
Aqueous solutions of Lu3+- perchlorate, triflate and chloride were measured by Raman spectroscopy. A weak, isotropic mode at 396 cm−1 (full width at half height (fwhh) at 50 cm−1) was observed in perchlorate and triflate solutions. This mode was assigned to the totally symmetric stretching mode of [Lu(OH2)8]3+, ν1LuO8. In Lu(ClO4)3 solutions in heavy water, the ν1LuO8 symmetric stretch of [Lu(OD2)8]3+ appears at 376.5 cm−1. The shift confirms the theoretical isotopic effect of this mode. In the anisotropic scattering of aqueous Lu(ClO4)3, five bands of very low intensity were observed at 113 cm−1, 161.6 cm−1, 231 cm−1, 261.3 cm−1 and 344 cm−1. In LuCl3 (aq) solutions measured over a concentration range from 0.105–3.199 mol·L−1 a 1:1 chloro-complex was detected. Its equilibrium concentration, however, disappeared rapidly with dilution and vanished at a concentration < 0.5 mol·L−1. Quantitative Raman spectroscopy allowed the detection of the fractions of [Lu(OH2)8]3+, the fully hydrated species and the mono-chloro complex, [Lu(OH2)7Cl]2+. In a ternary LuCl3/HCl solution, a mixtrure of chloro-complex species of the type [Lu(OH2)8−nCln]+3−n (n = 1 and 2) were detected. DFT geometry optimization and frequency calculations are reported for Lu3+- water cluster in vacuo and with a polarizable dielectric continuum (PC) model including the bulk solvent implicitly. The bond distance and angle for [Lu(OH2)8]3+ within the PC are in good agreement with data from structural experiments. The DFT frequencies for the Lu-O modes of [Lu(OH2)8]3+ and its deuterated analog [Lu(OD2)8]3+ in a PC are in fair agreement with the experimental ones. The calculated hydration enthalpy of Lu3+ (aq) is slightly lower than the experimental value.
Raman spectra of aqueous La3+, Ce3+, Pr3+, Nd3+ and Sm3+ - perchlorate solutions were measured and weak strongly polarized Raman bands were detected at 343 cm-1, 344 cm-1, 347 cm-1, 352 cm-1 and 363 cm-1, respectively. The full width at half height for these bands is quite broad (∼50 cm-1) in the isotropic spectrum and the band width increases with increasing solute concentration. The polarized Raman bands were assigned to the breathing modes of the nona-aqua ions of the mentioned rare earth ions. Published structural results confirmed that these ions exist as nona-hydrates in aqueous solutions [Ln(H2O)9]3+. The Ln-O bond distances of these rare earth ions correlate well with the band positions of the nona-aqua ions [Ln(OH2)9]+3 (Ln = La3+, Ce3+, Pr3+, Nd3+ and Sm3+) and the force constants were calculated for these breathing modes. The strength of the force constants increase with decreasing the Ln-O bond distances (La-O > Ce-O > Pr-O > Nd-O > Sm-O). While the fully hydrated ions are stable in dilute perchlorate solutions (∼0.2 mol L-1), in concentrated perchlorate solutions outer-sphere ion pairs and contact ion pairs are formed (C > 1.5 mol L-1). In a hydrate melt at 161 °C of Ce(ClO4)3 plus 6H2O, the contact ion pairs are the dominate species. The Raman bands of the ligated perchlorate and the Ce-O breathing mode of the partially hydrated ion pair at 326 cm-1 were measured and characterized. In cerium chloride solutions chloro-complex formation was detected over the measured concentration range from 0.270-2.167 mol L-1. The chloro-complexes in CeCl3(aq) are weak and diminish rapidly with dilution and disappear at a concentration <0.1 mol L-1. In a CeCl3 solution, with additional HCl, a series of chloro-complex species of the type [Ce(OH2)9-nCln]+3-n (n = 1, 2) were detected.
Aqueous solutions of La(CH3CO2)3, NaCH3CO2 and La(ClO4)3 were studied using Raman spectroscopy. In dilute NaCH3CO2 solution, acetate is fully hydrated and forms only minor amounts of ion pairs. The characteristic Raman bands are discussed and assigned. In fairly dilute La(ClO4)3 solutions, the La3+(aq) ion occurs as the nonahydrate. The separation of the carboxylate bands, νas – νs (Δ-value), in NaCH3CO2(cr) compared to La(CH3CO2)3·1.5H2O(cr) correlates with the bonding type of acetate which is “ionic” in the former but bidentate chelating/tridentate chelating in the latter. Other acetate bands such as the deformation mode of the CO2 moiety, δ CO2, and the two rocking vibrations (ρ), as well as the C–C stretch show marked differences in their band positions in NaCH3CO2(cr) compared to the ones in La(CH3CO2)3·1.5H2O(aq). In a ternary solution of La(CH3CO2)3/LaCl3 with a molar ratio La3+(aq): \( {\text{CH}}_{3} {\text{CO}}_{2}^{ - } \)(aq) = 3.87: 1.00), the bands of the bound acetate on La3+ were characterized and compared to those of fully hydrated acetate, \( {\text{CH}}_{3} {\text{CO}}_{2}^{ - } \left( {\text{aq}} \right) \). In this solution, almost all acetate is ligated to La3+ in a bidentate fashion and two complex species could be identified (molar ratios La3+: \( {\text{CH}}_{3} {\text{CO}}_{2}^{ - } \) = 1:1 and 1:2, respectively). In La(CH3CO2)3 solutions in H2O and D2O strong acetato complexes are formed and the bands of the bound acetate were characterized and compared with the ones of the fully hydrated acetate modes. A dilution series down to 0.0037 mol·L−1 in La(CH3CO2)3(aq) and to 0.0150 mol·L−1 in La(CH3CO2)3(D2O) showed that two acetate complexes are formed in these solutions. Again, it was shown that in these solutions the bound acetates on La3+ exist as bidentate ligands. DFT frequencies of the acetate on clusters {La(OH2)7O2CCH3)}2+ and {La(OH2)5(O2CCH3)2}+ compared well with the measured values. By determining the ligation number, \( \bar{n} \), it can be established that in dilute solutions, below 0.04 mol·L−1, a complex with a 1:1 stoichiometry (La3+: \( {\text{CH}}_{3} {\text{CO}}_{2}^{ - } \)) exists in equilibrium with “free” acetate while in more concentrated solutions a 1:2 complex also forms. La3+(aq) hydrolysis is slight and very small equilibrium concentrations of CH3COOH were detected (C–C stretch at 893 cm−1). From quantitative Raman measurements, K 1 was determined to be 160 ± 10 at 22 °C.
We report on a 62 year old patient who developed sepsis due to an infection caused by Porphyromonas pogonae, a recently described species of the bacterial genus Porphyromonas. This is the first case of an invasive infection with this pathogen.
There are a number of rare and, therefore, insufficiently described bacterial pathogens which are reported to cause severe infections especially in immunocompromised patients. In most cases only few data, mostly published as case reports, are available which investigate the role of such pathogens as an infectious agent. Therefore, in order to clarify the pathogenic character of such microorganisms, it is necessary to conduct epidemiologic studies which include large numbers of these bacteria. The methods used in such a surveillance study have to meet the following criteria: the identification of the strains has to be accurate according to the valid nomenclature, they should be easy to handle (robustness), economical in routine diagnostics and they have to generate comparable results among different laboratories. Generally, there are three strategies for identifying bacterial strains in a routine setting: 1) phenotypic identification characterizing the biochemical and metabolic properties of the bacteria, 2) molecular techniques such as 16S rRNA gene sequencing and 3) mass spectrometry as a novel proteome based approach. Since mass spectrometry and molecular approaches are the most promising tools for identifying a large variety of bacterial species, these two methods are described. Advances, limitations and potential problems when using these techniques are discussed.
Wild-type human interleukin-10 (hIL-10) is a non-covalent homodimer with a short half-life, thus limiting its therapeutic applications in vivo. To avoid loss of function due to dimer dissociation, we designed a synthetic hIL-10 analog by bridging both monomers via a 15 amino acid-long peptide spacer in a C-terminal to N-terminal fashion. For secretory expression in Escherichia coli, a 1156 bp fragment was generated from template vector pAZ1 by fusion PCR encoding a T7 promoter region and the signal sequence of the E. coli outer membrane protein F fused in frame to two tandem E. coli codon-optimized mature hIL-10 genes connected via a 45 nucleotide linker sequence. The construct was cloned into pUC19 for high-level expression in E. coli BL21 (DE3). The mean concentrations of hIL-10 fusion protein in the periplasm and supernatant of E. coli at 37 °C growth temperature were 130 ± 40 and 2 ± 1 ng/ml, respectively. The molecular mass of the recombinant protein was assessed via matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) analysis, indicating correct processing of the signaling sequence in E. coli. In vitro biological activity was shown by phosphorylation of signal transducer and activator of transcription protein 3 and suppression of tumor necrosis factor α secretion in lipopolysaccharide-stimulated macrophages.
Sodium acetate and acetate-d3solutions in water and heavy water were studied using Raman spectroscopy over a wide concentration range from 40–4200 cm−1and DFT calculations were performed on acetate–water clusters.