Distinguishing Natural Infections of the Bovine Mammary Gland by Staphylococcus from Streptococcus spp. Using Quantitative Milk Proteomics

Bovine mastitis is the most frequent disease on dairy farms, which leads to a decrease in the health welfare of the animals and great economic losses. This study was aimed at determining the quantitative variations in the milk proteome caused by natural infection by Staphylococcus and Streptococcus species in order to gain further understanding of any discrepancies in pathophysiology and host immune responses, independent of the mastitis level. After identification of Staphylococcus (N = 51) and Streptococcus (N = 67) spp., tandem mass tag (TMT)-labeled quantitative proteomic and liquid chromatography-mass spectrometry (LC-MS/MS) techniques on a modular Ultimate 3000 RSLCnano system coupled to a Q Exactive Plus was applied on aseptically sampled milk from Holstein cows. Proteome Discoverer was used for protein identification and quantitation through the SEQUEST algorithm. Statistical analysis employing R was used to identify differentially abundant proteins between the groups. Protein classes, functions and functional-association networks were determined using the PANTHER and STRING tools and pathway over-representation using the REACTOME. In total, 156 master bovine proteins were identified (two unique peptides, p < 0.05 and FDR < 0.001), and 20 proteins showed significantly discrepant abundance between the genera (p < 0.05 and FDR < 0.5). The most discriminatory proteins per group were odorant-binding protein (higher in staphylococci) and fibrinogen beta chain protein (higher in streptococci). The receiver operating characteristic (ROC) curve showed that protein kinase C-binding protein NELL2, thrombospondin-1, and complement factor I have diagnostic potential for differentiating staphylococci and streptococci intramammary infection and inflammation. Improved understanding of the host response mechanisms and recognition of potential biomarkers of specific-pathogen mastitis, which may aid prompt diagnosis for control implementation, are potential benefits of this study.

Origin of Decomposition in a Family of Molybdenum Precursor Compounds

The bis(tert-butylimido)-molybdenum(VI) framework has been used successfully in the design of vapor-phase precursors for molybdenum-containing thin films, so understanding its thermal behavior is important for such applications. Here, we report the thermal decomposition mechanism for a series of volatile bis(alkylimido)-dichloromolybdenum(VI) adducts with neutral N,N'-chelating ligands, to probe the stability and decomposition pathways for these molecules. The alkyl groups explored were tert-butyl, tert-pentyl, 1-adamantyl, and a cyclic imido (from 2,5-dimethylhexane-2,5-diamine). We also report the synthesis of the new tert-octyl imido adducts, (^tOctN)₂MoCl₂·L (L = N,N,N',N'-tetramethylethylenediamine or 2,2'-bipyridine), which have been fully characterized by spectroscopic techniques as well as single-crystal X-ray diffraction and thermal analysis. We found that the decomposition of all compounds follows the same general pathway, proceeding first by the dissociation of the chelating ligand to give the coordinatively unsaturated species (RN)₂MoCl₂. Subsequent dimerization results in either an imido bridged adduct, [(RN)Mo(μ-NR)Cl₂]₂, or a chloride bridged adduct, [(RN)₂Mo(μ-Cl)Cl]₂, depending on the size of the R group. The dimeric species then likely undergoes an intramolecular γ-hydrogen transfer to yield a nitrido-amido adduct, (RHN)MoNCl₂, and an alkene. Ultimately, the resulting molybdenum species appears to decompose into free tert-alkylamine and Mo₂N or Mo₂C. The thermolysis reactions have been monitored using ¹H NMR spectroscopy, and the volatile decomposition products were analyzed using gas chromatography-mass spectrometry. A key intermediate has also been detected using electron ionization high-resolution mass spectrometry. Finally, a detailed computational investigation supports the mechanism outlined above and helps explain the relative stabilities of different N,N'-chelated bis(alkylimido)-dichloromolybdenum(VI) adducts.

Atomic layer deposition of PbCl2, PbBr2 and mixed lead halide (Cl, Br, I) PbXnY2-n thin films

Atomic layer deposition offers outstanding film uniformity and conformality on substrates with high aspect ratio features. These qualities are essential for mixed-halide perovskite films applied in tandem solar cells, transistors and light-emitting diodes. The optical and electronic properties of mixed-halide perovskites can be adjusted by adjusting the ratios of different halides. So far ALD is only capable of depositing iodine-based halide perovskites whereas other halide processes are lacking. We describe six new low temperature (≤100 °C) ALD processes for PbCl₂ and PbBr₂ that are crucial steps for the deposition of mixed-halide perovskites with ALD. Lead bis[bis(trimethylsilyl)amide]-GaCl₃ and -TiBr₄ processes yield the purest, crystalline, uniform and conformal films of PbCl₂ and PbBr₂ respectively. We show that these two processes in combination with a PbI₂ process from the literature deposit mixed lead halide films. The four less optimal processes revealed that reaction by-products in lead halide deposition processes may cause film etching or incorporate themselves into the film.

Thermal Stability and Decomposition Pathways in Volatile Molybdenum(VI) Bis-imides

The vapor deposition of many molybdenum-containing films relies on the delivery of volatile compounds with the general bis(tert-butylimido)molybdenum(VI) framework, both in atomic layer deposition and chemical vapor deposition. We have prepared a series of (^tBuN)₂MoCl₂ adducts using neutral N,N'-chelates and investigated their volatility, thermal stability, and decomposition pathways. Volatility has been determined by thermogravimetric analysis, with the 1,4-di-tert-butyl-1,3-diazabutadiene adduct (5) found to be the most volatile (1 Torr of vapor pressure at 135 °C). Thermal stability was measured primarily using differential scanning calorimetry, and the 1,10-phenanthroline adduct (4) was found to be the most stable with an onset of decomposition of 303 °C. We have also investigated molybdenum compounds with other alkyl-substituted imido groups: these compounds all follow a similar decomposition pathway, γ-H activation, with varying reaction barriers. The tert-pentyl, 1-adamantyl, and a cyclic imido (from 2,5-dimethylhexane-2,5-diamine) were systematically studied to probe the kinetics of this pathway. All of these compounds have been fully characterized, including via single-crystal X-ray diffraction, and a total of 19 new structures are reported.

Synthesis, Characterization, and Thermal Study of Divalent Germanium, Tin, and Lead Triazenides as Potential Vapor Deposition Precursors

Only a few M-N bonded divalent group 14 precursors are available for vapor deposition, in particular for Ge and Pb. A majority of the reported precursors are dicoordinated with the Sn(II) amidinates, the only tetracoordinated examples. No Ge(II) and Pb(II) amidinates suitable for vapor deposition have been demonstrated. Herein, we present tetracoordinated Ge(II), Sn(II), and Pb(II) complexes bearing two sets of chelating 1,3-di-tert-butyltriazenide ligands. These compounds are thermally stable, sublime quantitatively between 60 and 75 °C (at 0.5 mbar), and show ideal single-step volatilization by thermogravimetric analysis.

A Rare Low-Spin CoIV Bis(β-silyldiamide) with High Thermal Stability: Steric Enforcement of a Doublet Configuration

Attempted preparation of a chelated Co^II β-silylamide resulted in the unprecedented disproportionation to Co⁰ and a spirocyclic cobalt(IV) bis(β-silyldiamide): [Co[(N^t Bu)₂ SiMe₂ ]₂ ] (1). Compound 1 exhibited a room-temperature magnetic moment of 1.8 B.M. and a solid-state axial EPR spectrum diagnostic of a rare S= 1 / 2 configuration for tetrahedral Co^IV . Ab initio semicanonical coupled-cluster calculations (DLPNO-CCSD(T)) revealed the doublet state was clearly preferred (-27 kcal mol^-1 ) over higher spin configurations only for the bulky tert-butyl-substituted analogue. Unlike other Co^IV complexes, 1 had remarkable thermal stability, and was demonstrated to form a stable self-limiting monolayer in preliminary atomic layer deposition (ALD) surface saturation experiments. The ease of synthesis and high stability make 1 an attractive starting point to investigate otherwise inaccessible Co^IV intermediates and for synthesizing new materials.

Designing Stability into Thermally Reactive Plumbylenes

Lead analogues of N-heterocyclic carbenes (NHPbs) are the least understood members of this increasingly important class of compounds. Here we report the design, preparation, isolation, structure, volatility, and decomposition pathways of a novel aliphatic NHPb: rac- N ², N ³-di- tert-butylbutane-2,3-diamido lead(II) (1Pb). The large steric bulk of the tert-butylamido moieties and rac-butane backbone successfully hinder redox decomposition pathways observed for diamidoethylene and -ethane backbone analogues, pushing the onset of thermal decomposition from below 0 °C to above 150 °C. With an exceptionally high vapor pressure of 1 Torr at 94 ± 2 °C and excellent thermal stability among Pb(II) complexes, 1Pb is a promising precursor for the chemical vapor deposition (CVD) and atomic layer deposition (ALD) of functional lead-containing materials.

In vivo EPR pharmacokinetic evaluation of the redox status and the blood brain barrier permeability in the SOD1G93A ALS rat model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder affecting the motor pathways of the central nervous system. Although a number of pathophysiological mechanisms have been described in the disease, post mortem and animal model studies indicate blood-brain barrier (BBB) disruption and elevated production of reactive oxygen species as major contributors to disease pathology. In this study, the BBB permeability and the brain tissue redox status of the SOD1^G93A ALS rat model in the presymptomatic (preALS) and symptomatic (ALS) stages of the disease were investigated by in vivo EPR spectroscopy using three aminoxyl radicals with different cell membrane and BBB permeabilities, Tempol, 3-carbamoyl proxyl (3CP), and 3-carboxy proxyl (3CxP). Additionally, the redox status of the two brain regions previously implicated in disease pathology, brainstem and hippocampus, was investigated by spectrophotometric biochemical assays. The EPR results indicated that among the three spin probes, 3CP is the most suitable for reporting the intracellular redox status changes, as Tempol was reduced in vivo within minutes (t_1/2 =2.0±0.5min), thus preventing reliable kinetic modeling, whereas 3CxP reduction kinetics gave divergent conclusions, most probably due to its membrane impermeability. It was observed that the reduction kinetics of 3CP in vivo, in the head of preALS and ALS SOD1^G93A rats was altered compared to the controls. Pharmacokinetic modeling of 3CP reduction in vivo, revealed elevated tissue distribution and tissue reduction rate constants indicating an altered brain tissue redox status, and possibly BBB disruption in these animals. The preALS and ALS brain tissue homogenates also showed increased nitrilation, superoxide production, lipid peroxidation and manganese superoxide dismutase activity, and a decreased copper-zinc superoxide dismutase activity. The present study highlights in vivo EPR spectroscopy as a reliable tool for the investigation of changes in BBB permeability and for the unprecedented in vivo monitoring of the brain tissue redox status, as early markers of ALS.

Iron-sulfur cluster damage by the superoxide radical in neural tissues of the SOD1(G93A) ALS rat model

Extensive clinical investigations, in hand with biochemical and biophysical research, have associated brain iron accumulation with the pathogenesis of the amyotrophic lateral sclerosis (ALS) disease. The origin of iron is still not identified, but it is proposed that it forms redox active complexes that can participate in the Fenton reaction generating the toxic hydroxyl radical. In this paper, the state of iron in the neural tissues isolated from SOD1(G93A) transgenic rats was investigated using low temperature EPR spectroscopy and is compared with that of nontransgenic (NTg) littermates. The results showed that iron in neural tissues is present as high- and low-spin, heme and non-heme iron. It appears that the SOD1(G93A) rat neural tissues were most likely exposed in vivo to higher amounts of reactive oxygen species when compared to the corresponding NTg tissues, as they showed increased oxidized [3Fe-4S](1+) cluster content relative to [4Fe-4S](1+). Also, the activity of cytochrome c oxidase (CcO) was found to be reduced in these tissues, which may be associated with the observed uncoupling of heme a3 Fe and CuB in the O2-reduction site of the enzyme. Furthermore, the SOD1(G93A) rat spinal cords and brainstems contained more manganese, presumably from MnSOD, than those of NTg rats. The addition of potassium superoxide to all neural tissues ex vivo, led to the [4Fe-4S]→[3Fe-4S] cluster conversion and concurrent release of Fe. These results suggest that the superoxide anion may be the cause of the observed oxidative damage to SOD1(G93A) rat neural tissues and that the iron-sulfur clusters may be the source of poorly liganded redox active iron implicated in ALS pathogenesis. Low temperature EPR spectroscopy appears to be a valuable tool in assessing the role of metals in neurodegenerative diseases.

Imaging Reactive Oxygen Species-Induced Modifications in Living Systems

SIGNIFICANCE

Reactive Oxygen Species (ROS) may regulate signaling, ion channels, transcription factors, and biosynthetic processes. ROS-related diseases can be due to either a shortage or an excess of ROS.

RECENT ADVANCES

Since the biological activity of ROS depends on not only concentration but also spatiotemporal distribution, real-time imaging of ROS, possibly in vivo, has become a need for scientists, with potential for clinical translation. New imaging techniques as well as new contrast agents in clinically established modalities were developed in the previous decade.

CRITICAL ISSUES

An ideal imaging technique should determine ROS changes with high spatio-temporal resolution, detect physiologically relevant variations in ROS concentration, and provide specificity toward different redox couples. Furthermore, for in vivo applications, bioavailability of sensors, tissue penetration, and a high signal-to-noise ratio are additional requirements to be satisfied.

FUTURE DIRECTIONS

None of the presented techniques fulfill all requirements for clinical translation. The obvious way forward is to incorporate anatomical and functional imaging into a common hybrid-imaging platform. Antioxid. Redox Signal. 24, 939-958.

Determination of anisomycin in tissues and serum by LC-MS/MS: application to pharmacokinetic and distribution studies in rats

The first study on anisomycin pharmacokinetics in rats using a new preparation method for tissues and serum and LC-MS/MS analysis.

In vivo evaluation of different alterations of redox status by studying pharmacokinetics of nitroxides using magnetic resonance techniques

Free radicals, particularly reactive oxygen species (ROS), are involved in various pathologies, injuries related to radiation, ischemia-reperfusion or ageing. Unfortunately, it is virtually impossible to directly detect free radicals in vivo, but the redox status of the whole organism or particular organ can be studied in vivo by using magnetic resonance techniques (EPR and MRI) and paramagnetic stable free radicals - nitroxides. Here we review results obtained in vivo following the pharmacokinetics of nitroxides on experimental animals (and a few in humans) under various conditions. The focus was on conditions where the redox status has been altered by induced diseases or harmful agents, clearly demonstrating that various EPR/MRI/nitroxide combinations can reliably detect metabolically induced changes in the redox status of organs. These findings can improve our understanding of oxidative stress and provide a basis for studying the effectiveness of interventions aimed to modulate oxidative stress. Also, we anticipate that the in vivo EPR/MRI approach in studying the redox status can play a vital role in the clinical management of various pathologies in the years to come providing the development of adequate equipment and probes.

Analysis of (7)Be behaviour in the air by using a multilayer perceptron neural network

A multilayer perceptron artificial neural network (ANN) model for the prediction of the (7)Be behaviour in the air as the function of meteorological parameters was developed. The model was optimized and tested using (7)Be activity concentrations obtained by standard gamma-ray spectrometric analysis of air samples collected in Belgrade (Serbia) during 2009-2011 and meteorological data for the same period. Good correlation (r = 0.91) between experimental values of (7)Be activity concentrations and those predicted by ANN was obtained. The good performance of the model in prediction of (7)Be activity concentrations could provide basis for construction of models which would forecast behaviour of other airborne radionuclides.

Increased survival after irradiation followed by regeneration of bone marrow stromal cells with a novel thiol-based radioprotector

Aim

To investigate the survival of laboratory rats after irradiation and to study the cellularity of their bone marrow and the multipotential mesenchymal stem cells (BM-MSCs) in groups treated with or without a new thiol-based radioprotector (GM2011)

Methods

Animals were irradiated by a Cobalt gamma source at 6.7 Gy. Treated animals were given i.p. GM2011 30 minutes before and 3 and 7 hours after irradiation. Controls consisted of sham irradiated animals without treatment and animals treated without irradiation. After 30 days post-irradiation, animals were sacrificed and bone marrow cells were prepared from isolated femurs. A colony forming unit-fibroblast (CFU-F) assay was performed to obtain the number of BM-MSCs.

Results

In the treated group, 87% of animals survived, compared to only 30% in the non-treated irradiated group. Irradiation induced significant changes in the bone marrow of the treated rats (total bone marrow cellularity was reduced by ~ 60% – from 63 to 28 cells ×10⁶/femur and the frequency of the CFU-F per femur by ~ 70% – from 357 to 97), however GL2011 almost completely prevented the suppressive effect observed on day 30 post-irradiation (71 cells ×10⁶/femur and 230 CFU-F/femur).

Conclusion

Although the irradiation dosage was relatively high, GL2011 acted as a very effective new radioprotector. The recovery of the BN-MSCs and their counts support the effectiveness of the studied radioprotector.

Brain iron MRI: a biomarker for amyotrophic lateral sclerosis

PURPOSE

To evaluate the usefulness of MRI detection of hypointensity areas (iron deposits) in the brain using a dedicated MRI technique in patients with ALS in establishing this sign as a potential surrogate biomarker that correlates with the severity of disease.

MATERIALS AND METHODS

Forty-six ALS patients and 26 age-matched controls were examined by MRI. The ALS Functional Rating Scale (ALSFRS) score was determined before the first MRI examination. The sub-set of 25 ALS patients was re-examined around 6 months after the first MRI examination. The MRI examination consisted of routine T1W, T2W, and FLAIR sequences with the addition of a thin slice heavily T2* weighted sequence to accentuate magnetic susceptibility artifacts.

RESULTS

T2*W sequence is superior to any other MRI sequence in detecting hypointensities in the brain of ALS patients. Hypointensities were found only in the precentral gyruses gray matter (PGGM) and were detected in 42 patients. The extent of hypointensities was measured and scored (0-3) and correlated with ALSFRS (r = -0.545). Twenty-five patients were re-examined 6 months later, and the majority of them showed the shift toward higher MRI scores. No control subjects had hypointensities in PGGM.

CONCLUSION

The detection of hypointensities in PGGM appears to be a very promising surrogate MRI biomarker for ALS due to its simplicity, high sensitivity and specificity, suitability for longitudinal studies, and relationship with the pathogenesis of the disease.

Distribution of natural radionuclides in surface soils in the vicinity of abandoned uranium mines in Serbia

The activity concentrations of natural radionuclides in soils from the area affected by uranium mining at Stara Planina Mountain in Serbia were studied and compared with the results obtained from an area with no mining activities (background area). In the affected area, the activity concentrations ranged from 1.75 to 19.2 mg kg(-1) for uranium and from 1.57 to 26.9 mg kg(-1) for thorium which is several-fold higher than those in the background area. The Th/U, K/U, and K/Th activity ratios were also determined and compared with data from similar studies worldwide. External gamma dose rate in the air due to uranium, thorium, and potassium at 1 m above ground level in the area affected by uranium mining was found to be 91.3 nGy h(-1), i.e., about two-fold higher than that in background area. The results of this preliminary study indicate the importance of radiological evaluation of the area and implementation of remedial measures in order to prevent further dispersion of radionuclides in the environment.

Imaging cellular markers of neuroinflammation in the brain of the rat model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurological disorder affecting upper and lower motoneurons. Since immune disbalance is known to be an important manifestation of the disease, working with the familial ALS rat model, hSODG93A (containing multiple copies of the human SOD1 G93A mutation), we were particularly interested in following by live magnetic resonance imaging (MRI) the immune cells labeled by ultra small paramagnetic iron oxide (USPIO) nanoparticles. In addition, microglial activation was studied by immunocytochemistry. MRI of USPIO labeled Tcells revealed CD4+ lymphocyte infiltration in the midbraininterbrain region while the CD8+ cells were more confined to the brainstem region. By way of gadolinium (Gd) contrast it was also confirmed that the bloodbrain barrier (BBB) was compromised. Moreover, it was revealed that the regions of BBB breakthrough were congruent with the MRI foci of Tcell infiltration. Immunocytochemistry revealed microglial activation and fusion, possibly phagocytic interactions with neurons in the hippocampus and brainstem. These observations prove the existence of an elaborate inflammatory process in the brain of hSODG93A rats, and also demonstrates the complexity and multifocality of ALS as having its inflammatory manifestations also in the central nervous system (hippocampus) distinct from clinically described motor foci of degeneration.

Decreased oxygen transfer capacity of erythrocytes as a cause of 5-fluorouracil related ischemia

Various mechanisms have been proposed to account for chemotherapy related ischemia, but none of them can explain the available clinical data. In order to explore the possibility that the decreased ability of erythrocytes to deliver oxygen to the heart could be responsible for cardiotoxicity, we have performed an ex vivo and in vivo study of the effects of cisplatin/5-FU on erythrocytes, using a variety of biophysical techniques. Combining EPR and microscopy it was concluded that both cardiotoxic 5-FU and non-cardiotoxic cisplatin have similar effects on the erythrocyte membrane, thus eliminating those changes as a potential source of cardiotoxicity. On the contrary, 31P-NMR and polarography showed that the effects of these cytostatics on the intracellular milieu differ significantly. 5-FU provoked a pronounced decrease of the O2 level in blood and affected the metabolism of phosphate compounds, while cisplatin had no such effects. When combined these two drugs showed synergistic effects, which matches the higher frequency of cardiotoxicity of the combination relative to the sole application of 5-FU. Preliminary results acquired on blood of patients receiving cisplatin/5-FU therapy verified observations obtained ex vivo. These results open a possibility of applying NMR in preclinical trials of new drugs in order to predict their ischemic potential.