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Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many, if not all of the tannin hydroxyl groups with -NH2 groups. A tannin-aminated tannin (ATT) particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-linking the two by substituting tannin's hydroxyl groups with the -NH2 groups on the aminated tannin to form -NH-bridges between the two. The resulting particleboard coating gave encouraging results when pressed at 180°C for 3 min. Conversely, the system in which tannin was reacted/cross-liked with urea (ATU) by a similar amination reaction did not perform as well as the ATT system, and this even when a higher curing temperature and longer hot press time were used. In particular its water repellence was worse probably due to the presence of urea and such a system with lower reactivity. Nonetheless, substituting the tannin -OHs with the urea -NH2 groups appeared to also take place. ATT gave better results than ATU as regards water repellence and mechanical resistance as shown by the cross cut test. The ATT system was shown to be between 95% and 98% biosourced. The difference appeared to be due, by TMA analysis, to the much faster formation of the ATT hardened network leading to a better cross-linked polymer coating. The chemical species formed for both the ATT and ATU system were studied by MALDI ToF and CP MAS 13C NMR. [ABSTRACT FROM AUTHOR]

Introduction: Laboratory surveillance of Streptococcus pneumoniae serotypes plays a crucial role in effectively implementing vaccines to prevent invasive pneumococcal diseases. The conventional method of serotyping, known as the Quellung reaction, is both time-consuming and expensive. However, the emergence of MALDI-TOF MS technology has revolutionized microbiology laboratories by enabling rapid and cost-effective serotyping based on protein profiles. Objectives: In this study, we aimed to investigate the viability of utilizing MALDI-TOF MS technology as an adjunctive and screening method for capsular typing of Streptococcus pneumoniae. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates. Methods: Firstly, we established a comprehensive spectral database comprising isolates of serotypes present in the PCV13 vaccine, along with the top 10 most prevalent NON PCV13 serotypes based on local epidemiological data. This database served as a foundation for developing unsupervised models utilizing MALDI-TOF MS spectra, which enabled us to identify inherent patterns and relationships within the data. Our analysis involved a dataset comprising 215 new isolates collected from nationwide surveillance in Argentina. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates. Results: Although our findings revealed suboptimal performance in serotype classification, they provide valuable insights into the potential of machine learning algorithms in this context. The sensitivity of the models ranged from 0.41 to 0.46, indicating their ability to detect certain serotypes. The observed specificity consistently remained at 0.60, suggesting a moderate level of accuracy in identifying non-vaccine serotypes. These results highlight the need for further refinement and optimization of the algorithms to enhance their discriminative power and predictive accuracy in serotype identification.By addressing the limitations identified in this study, such as exploring alternative feature selection techniques or optimizing algorithm parameters, we can unlock the full potential of machine learning in robust and reliable serotype classification of S. pneumoniae. Our work not only provides a comprehensive evaluation of multiple machine learning models but also emphasizes the importance of considering their strengths and limitations. Conclusion: Overall, our study contributes to the growing body of research on utilizing MALDI-TOF MS and machine learning algorithms for serotype identification purposes.

Melamine-dialdehyde starch resins used for wood surface finishes have been developed. The reaction of melamine with dialdehyde starch has been shown to occur by FTIR and MALDI ToF spectrometry, with several oligomer species due to the reaction of the two materials being identified, and the resin thermal stability was studied by thermogravimetric analysis. The resins were prepared by two different procedures when it was realized that dialdehyde starch is sensitive to too high a temperature for prolonged times. The melamine-dialdehyde starch resins were applied on particleboard supports as a direct liquid surface finish and a resin-impregnated paper. The surface finishes were tested for adhesion by the cross-cut test, their initial sessile drop contact angle, and the contact angle evolution as a function of time. The best results were obtained by the resins catalyzed by 2% ammonium sulfate and applied to the support surface as a resin-impregnated paper hot pressed for 3 min at 200°C, although the results at 180°C also looked promising. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effectiveness of MALDI‑ToF mass spectrometry in the identification of collection and newly isolated strains of tularemia pathogen using the database “Protein profiles of mass spectra of microorganisms belonging to I–II pathogenicity groups for the MALDI Biotyper software”.Materials and methods. We investigated 142 strains of Francisella tularensis, including 59 collection strains and 83 newly isolated ones. Bacteriological, molecular-genetic and proteomic research methods were used to identify them. The acquisition of mass spectra, analysis, generation and expansion of reference libraries were performed on a mass analyzer “Microflex LT” using FlexControl v. 3.3, FlexAnalysis v. 3.3, and MALDI Biotyper 3.0 software packages. The cluster analysis was performed using the BioNumerics 7.6 software.Results and discussion. The possibility of identifying tularemia pathogen has been assessed using the extended database for MALDI Biotyper 3.0 “Protein profiles of mass spectra of microorganisms belonging to I–II pathogenicity groups for the MALDI Biotyper software”. During identification to the species level, the significance of mass spectrometry results for collection strains and newly isolated ones was 91.5 % and 97.6 %, respectively. In determining the genus appurtenance, the reliability of identification was 100 %. Thus, the MALDI‑ToF mass spectrometry method allows for accurate species and genus identification of F. tularensis strains. Based on the cluster analysis of 66 F. tularensis strains in BioNumerics 7.6 software using «Pearson correlation» and the UPGMA algorithm, the possibility of subspecies differentiation has been evaluated. Due to the similarity of protein profiles of F. tularensis strains, a clear differentiation into subspecies could not be achieved. It is necessary to use other options for sample preparation, new generation devices with higher resolution, as well as apply additional approaches and analysis tools for successful subspecific differentiation.

Identifying fungal clones propagated during outbreaks in hospital settings is a problem that increasingly confronts biologists. Current tools based on DNA sequencing or microsatellite analysis require specific manipulations that are difficult to implement in the context of routine diagnosis. Using deep learning to classify the mass spectra obtained during the routine identification of fungi by MALDI-TOF mass spectrometry could be of interest to differentiate isolates belonging to epidemic clones from others. As part of the management of a nosocomial outbreak due to Candida parapsilosis in two Parisian hospitals, we studied the impact of the preparation of the spectra on the performance of a deep neural network. Our purpose was to differentiate 39 otherwise fluconazole-resistant isolates belonging to a clonal subset from 56 other isolates, most of which were fluconazole-susceptible, collected during the same period and not belonging to the clonal subset. Our study carried out on spectra obtained on four different machines from isolates cultured for 24 or 48 h on three different culture media showed that each of these parameters had a significant impact on the performance of the classifier. In particular, using different culture times between learning and testing steps could lead to a collapse in the accuracy of the predictions. On the other hand, including spectra obtained after 24 and 48 h of growth during the learning step restored the good results. Finally, we showed that the deleterious effect of the device variability used for learning and testing could be largely improved by including a spectra alignment step during preprocessing before submitting them to the neural network. Taken together, these experiments show the great potential of deep learning models to identify spectra of specific clones, providing that crucial parameters are controlled during both culture and preparation steps before submitting spectra to a classifier. [ABSTRACT FROM AUTHOR]

There are several sources of mine drainage left over from past mining sites in the Central Slovakian neovolcanites. The neutral pH and high concentrations of sulphates and multiple potentially hazardous elements, such as zinc or manganese, are typical in this region. However, this environment could be home to specific microbiota. The aim of the study was to characterize bacterial populations in mine drainage in the Central Slovakian neovolcanites. Direct microscopic observations, cultivation methods, MALDI TOF mass spectrometry, and 16S rRNA gene sequencing of isolates were used for identification. Gram-positive and Gram-negative bacteria were almost equally represented in the mine water samples. The most abundant bacterium was the genus Bacillus spp. (43.48%). Another large group of bacteria consisted of Proteobacteria (34.78%), represented by Pseudomonas spp. (17.39%), Serratia spp. (13.04%), and Providencia spp. (4.35%). Our data confirm the presence of Bacillus spp. and Pseudomonas spp. as bacterial species occurring in an environment polluted by potentially hazardous elements, which may indicate their bioremediation potential. [ABSTRACT FROM AUTHOR]

Nocardia microorganisms are saprophytes, either non-pathogenic or pathogenic, causing nocardiosis. The clinically significant disease occurs in immunocompromised people, most often as pneumonia with cough, dyspnea, and fever. Antibiotic therapy, which is longer in time, is necessary. The main treatment is with sulfonamides, but the sensitivity of these bacteria varies. Therefore, the antibiotic susceptibility of the respective strain is important to apply combined therapy if needed. The risk of death without treatment is high, especially if the infection disseminates and the brain is involved. Antibacterial prophylaxis is therefore recommended in patients at high risk of nocardiosis. Our clinical case concerns an immunocompromised patient with isolated Nocardia from bronchoalveolar lavage (BAL).

Recently, the problem of increasing the productivity of farm animals is one of the most important for veterinary medicine. Since the animals “programmed” for maximum productivity by selection turned out to be excessively exposed to anthropogenic and biological negative factors, the result of this is a decrease in their productivity. Conducted toxicological, microbiological, mycological and chromatographic studies of the organic feed additive ˮGreenat“, which includes humic acids. It is promising to study the possibility of using preparations containing humic substances to increase the productivity of farm animals and poultry, to enhance the general nonspecific resistance of the body. Given that peat is the raw material for the manufacture of the additive, toxicity, mycological and microbiological indicators are extremely important. Toxicological studies (bioassays on rabbits and Colpoda steinii culture) proved the absence of toxic substances, as evidenced by the activity of the colpoda infusoria for 10 minutes and 3 hours of the study, and the absence of hyperemia and inflammation on the skin of the rabbit. The number of mold fungi does not exceed the allowable limits of 1.5x102 CFU/g (according to the norm 5.0x104), qualitative studies revealed and identified by mass spectrometry the mold fungi A. alternata; C. cladosporioides, which belong to saprophytes and get into the organic feed additive "Grinat" from the remains of plants during their decomposition. Microscopic fungi Alternaria spp. participate in the decomposition and mineralization of plant residues due to the polygalacturonase enzyme complex, which allows them to attach themselves and exist in various conditions. Cladosporium spp. found outdoors and indoors, in degraded organic debris, produce secondary metabolites such as antibiotics that are inhibitors of B. subtilis, E. coli, and C. albicans. Microbiologically, Maldi Tof mass spectrometry detected Bacillus megaterium, which belongs to soil bacteria, and Staphylococcus hominis, found as a harmless commensal on the skin of humans and animals. Chromatographically confirmed the presence of essential amino acids: leucine (0.120%), valine (0.089%), threonine (0.064%), phenylalanine (0.039%), isoleucine (0.024%), histidine (0.021), methionine (0.011%), lysine (0.05%), tryptophan (0.007%). Accordingly, conditionally replaceable and non-essential amino acids, which can help to avoid a shortage of feed components in animal diets.

Condensed tannin copolymerized with hyperbranched tris(2-aminoethyl)amine-urea formed by amine-amido deamination yields a particleboard thermosetting adhesive without any aldehydes satisfying the requirements of relevant standards for the particleboard internal bond strength. The tannin–triamine–urea cures well at 180 °C, a relatively low temperature for today's particleboard hot pressing. As aldehydes were not used, the formaldehyde emission was found to be zero, not even in traces due to the heating of wood. The effect is ascribed to the presence of many reactive sites, such as amide, amino, and phenolic groups belonging to the three reagents used. The tannin appears to function as an additional cross-linking agent, almost a nucleating agent, for the triamine–urea hyperbranched oligomers. Chemical analysis by MALDI ToF and 13C NMR has shown that the predominant cross-linking reaction is that of the substitution of the tannin phenolic hydroxyls by the amino groups of the triamine. The reaction of tannin with the still-free amide groups of urea is rather rare, but it may occur with the rarer tannin flavonoid units in which the heterocyclic ring is opened. Due to the temperature gradient between the surfaces and the board core in the particleboard during hot pressing, the type and the relative balance of covalent and ionic bonds in the resin structure may differ in the surfaces and the board core. [ABSTRACT FROM AUTHOR]

This article presents the first applied results of using citric acid in combinations with a melamine-urea-formaldehyde (MUF) resin for bonding wood veneers. The chemical reactions involved are shown based on a MALDI ToF analysis of the reaction of the MUF resin with citric acid. The preliminary results of the physical and mechanical properties of the LVL prepared are also presented. Veneers from Populus sp were used to manufacture 5-layer laminated veneer lumber (LVL) of small dimensions. Five combinations of the amount of citric acid, MUF spread rate and pressing parameters were tested. LVL bonded with 20% of citric acid + 100 g/m² of MUF, hotpressed using a 3-step process with maximum 1.5 MPa of pressure yielded the board with better dimensional stability and mechanical properties. It could be concluded that citric acid in combination with MUF can be used for bonding wood veneer and the research should be continued to study further the parameters involved and to enhance the results. [ABSTRACT FROM AUTHOR]

We studied a strain of Bacillus isolated from an artisanal tannery in Salta, Argentina. It was identified as Bacillus licheniformis B6 by 16 S phylogenetic analysis and MALDI TOF (GenBank accession code No. KP776730). The synthesis of lipopeptides by B6 and their antibacterial activity against clinical pathogenic strains was analyzed both in the cell-free supernatant (CFS) and in the crude fraction of lipopeptides (LF). Overall, the CFS did not significantly reduce the viability of the studied strains (Staphylococcus aureus 269 and ATCC 43,300, Escherichia coli 4591 and 25,922, Klebsiella sp. 1087 and 1101). However, LF at 9 mg/mL reduced the viability of those pathogenic strains by 2 and 3 log orders compared to those of the control. When the effects of LF and ampicillin were compared, they showed different sensitivity against pathogenic strains. For example, E. coli 4591 was the strain most resistant to ampicillin, requiring 250 mg/mL of antibiotic to achieve the same inhibitory effect as 9 mg/mL of B6 LF. SEM observations of the effect of LF on biofilm formation by E. coli 4591 and Klebsiella sp. 1087 clearly showed that biofilm structures were destabilized, these strains turning into weak biofilm formers. Signals in the CFS and LF corresponding to kurstakin and iturin were identified by MALDI TOF. Interestingly, surfactin was detected, rather than lichenysin, the expected lipopeptide in B. licheniformis species. Signals of bacitracin and fengycins were also found, the latter with a higher number of homologues and relative intensity in the LF than the other lipopeptides. These results show that the lipopeptides synthesized by B. licheniformis B6 have both potential antibacterial and anti-biofilm activity against pathogenic bacteria of health importance. Highlights: Bacillus licheniformis B6 (Genbank accession code Nº KP776730, isolated from an artisanal tannery) synthesizes lipopeptides with biological activity. The crude fraction of lipopeptides (LF) had antagonistic action against Staphylococcus aureus 269 and ATCC 43300, Escherichia coli 4591 and 25922, Klebsiella sp. 1087 and 1101. 9 mg/mL of B6 LF were effective to inhibit E. coli 4591, whereas 250 mg/mL of ampicillin were necessary to elicit a similar effect. SEM observations of the effect of LF on biofilm formation by E. coli 4591 and Klebsiella sp. 1087 clearly showed that biofilm structures were destabilized. Signals in the LF corresponding to kurstakins and iturin were identified by MALDI TOF; surfactin was detected instead of lichenysin. [ABSTRACT FROM AUTHOR]

We present a case concerning a 65-year-old, previously healthy gentleman who was found to have infective endocarditis after presenting with a four-month history of constitutional symptoms. Blood tests taken in the community showed elevated inflammatory markers and a deterioration in renal function, which prompted his referral for inpatient investigations. Blood cultures and a transesophageal echocardiogram subsequently confirmed native valve endocarditis affecting both the aortic and mitral valves. Infective endocarditis is common in an infectious disease physician's daily practice, but this particular case is notable since the causative agent, Streptococcus sinensis , is an extremely rare viridans group Streptococcus , which has been reported only sporadically in other European countries. The patient was started on appropriate anti-microbial treatment and was scheduled for surgery to replace both affected valves. He developed signs and symptoms of congestive heart failure after 10 days of anti-microbial treatment and underwent dual valve replacement surgery. Despite optimal anti-microbial therapy and multiorgan support in a cardiac intensive care unit, the patient passed away two weeks after surgery as a result of ventilator-associated pneumonia., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Tabone Adami et al.)

Identifying fungal clones propagated during outbreaks in hospital settings is a problem that increasingly confronts biologists. Current tools based on DNA sequencing or microsatellite analysis require specific manipulations that are difficult to implement in the context of routine diagnosis. Using deep learning to classify the mass spectra obtained during the routine identification of fungi by MALDI-TOF mass spectrometry could be of interest to differentiate isolates belonging to epidemic clones from others. As part of the management of a nosocomial outbreak due to Candida parapsilosis in two Parisian hospitals, we studied the impact of the preparation of the spectra on the performance of a deep neural network. Our purpose was to differentiate 39 otherwise fluconazole-resistant isolates belonging to a clonal subset from 56 other isolates, most of which were fluconazole-susceptible, collected during the same period and not belonging to the clonal subset. Our study carried out on spectra obtained on four different machines from isolates cultured for 24 or 48 h on three different culture media showed that each of these parameters had a significant impact on the performance of the classifier. In particular, using different culture times between learning and testing steps could lead to a collapse in the accuracy of the predictions. On the other hand, including spectra obtained after 24 and 48 h of growth during the learning step restored the good results. Finally, we showed that the deleterious effect of the device variability used for learning and testing could be largely improved by including a spectra alignment step during preprocessing before submitting them to the neural network. Taken together, these experiments show the great potential of deep learning models to identify spectra of specific clones, providing that crucial parameters are controlled during both culture and preparation steps before submitting spectra to a classifier.

There are several sources of mine drainage left over from past mining sites in the Central Slovakian neovolcanites. The neutral pH and high concentrations of sulphates and multiple potentially hazardous elements, such as zinc or manganese, are typical in this region. However, this environment could be home to specific microbiota. The aim of the study was to characterize bacterial populations in mine drainage in the Central Slovakian neovolcanites. Direct microscopic observations, cultivation methods, MALDI TOF mass spectrometry, and 16S rRNA gene sequencing of isolates were used for identification. Gram-positive and Gram-negative bacteria were almost equally represented in the mine water samples. The most abundant bacterium was the genus Bacillus spp. (43.48%). Another large group of bacteria consisted of Proteobacteria (34.78%), represented by Pseudomonas spp. (17.39%), Serratia spp. (13.04%), and Providencia spp. (4.35%). Our data confirm the presence of Bacillus spp. and Pseudomonas spp. as bacterial species occurring in an environment polluted by potentially hazardous elements, which may indicate their bioremediation potential.

Nowadays ornithobacteriosis is widespread among industrial poultry in Ukraine and the world. The disease leads to significant economic losses. The large variation in the serotypes of the bacteria complicates the treatment of the disease. The study of microscopic changes that occur in organs during ornithobacteriosis will help to better understand the pathogenesis of the disease development. Ornithobacteriosis was diagnosed in clinically sick broiler chickens by bacteriological studies using Maldi Tof mass-spectrometry. As a result of the antibiotic sensitivity test, the pathogen was found to be sensitive to doxycycline, tilmicosin, rifampicin, cefazolin, amoxiclav and benzylpenicillin. Histological studies of internal organs – trachea, lungs, heart, kidneys, liver and spleen – were carried out. It was found that with spontaneous ornithobacteriosis of broiler chickens, the most expressive microscopic changes occur in the respiratory organs – the lungs and trachea and are characterized by a decrease in the lumen of the parabronchials due to edema of their walls and infiltration with lymphocytes, the absence of epithelium on the surface of the parabronchials, narrowing of the air capillaries of the parabronchial complexes, hemorrhages in the parenchyma of the parabronchial complexes, vasodilatation of the lung vessels and overflow of their blood vessels with blood cells, edema around the epithelium trachea, destruction of part of the tracheal mucosa epithelial cells, edema of its submucosa, expansion and overflow of blood vessels of the mucous membrane with blood cells. In the spleen there was a uniform diffuse edema of the parenchyma and a decrease in the number of lymphocytes in the lymphoid follicles; in the kidneys – expansion and overflow of the stroma blood vessels, uneven edema of the glomeruli of one part of the renal corpuscles and destruction of the glomeruli of another, granular degeneration of the convoluted and straight tubules of the kidneys; in the liver – edema, hemorrhage, violation of the hepatic lobules’ structure, expansion of the hepatic veins, granular degeneration of hepatocytes or their destruction; in the heart – edema of the myocardial interstitium, muscle fibers’ granular dystrophy, fragmentation of muscle fibers as a result of their rupture. Histological research of ORT infected chickens will lead to a better understanding the mechanism of pathological changes at the microscopic level, which will facilitate the development of more effective methods of treatment and prevention of the disease.

BackgroundMycoplasma hominis is a small cell-wall-free organism, part of the normal microbiota of the genitourinary tract. It is rarely involved in extragenital infections, mainly joint, surgical-site, and respiratory infections.MethodsWe describe a case of M. hominis subdural empyema and lower limb surgical site infections, following decompressive craniotomy, after traumatic brain and extremities injury. In addition, a literature review of 34 cases M. hominis CNS infections was done.ResultsOur case depicts a 25-years old patient who developed subdural empyema and surgical site infections in his cranium and fibula. Both sites were cultured, and small pinpoint colonies grew on blood agar. MALDI-TOF MS identified M. hominis. Simultaneously 16S-rDNA PCR from CSF detected M. hominis. Antimicrobial treatment was switched to doxycycline with improvement. Literature review revealed 21 adults and 13 pediatric cases of M. hominis CNS infection. Risk factors in adults were head trauma, neurosurgery, or post-partum period.ConclusionsBased upon the literature reviewed, we postulate that adult patients with head trauma or neurosurgical procedure, rarely are infected either through direct contamination during the trauma, or by undergoing urgent, urinary catheterization, and may experience distant infection due to translocation of M. hominis into the bloodstream. In such cases diagnosis is delayed due to difficulties in growing and identifying the bacteria. Empiric antimicrobials are usually not effective against mycoplasmas. These factors contributed to the mortality in adult cases (15%). Our rare case highlights the necessity of combining classical microbiology routines with advanced molecular techniques to establish a diagnosis in complicated cases.

Diabetes mellitus has become a major global health issue. Currently, the use of antibiotics remains the best foundational strategy in the control of diabetic foot infections. However, the lack of accurate identification of pathogens and the empirical use of antibiotics at early stages of infection represents a non-targeted treatment approach with a poor curative effect that may increase the of bacterial drug resistance. Therefore, the timely identification of drug resistant bacteria is the key to increasing the efficacy of treatments for diabetic foot infections. The traditional identification method is based on bacterial morphology, cell physiology, and biochemistry. Despite the simplicity and low costs associated with this method, it is time-consuming and has limited clinical value, which delays early diagnosis and treatment. In the recent years, MALDI-TOF MS has emerged as a promising new technology in the field of clinical microbial identification. In this study, we developed a strategy for the identification of drug resistance in the diagnosis of diabetic foot infections using a combination of macro-proteomics and MALDI MS analysis. The macro-proteomics result was utilized to determine the differential proteins in the resistance group and the corresponding peptide fragments were used as the finger print in a MALDI MS analysis. This strategy was successfully used in the research of drug resistance in patients with diabetic foot infections and achieved several biomarkers that could be used as a finger print for 4 different drugs, including ceftazidime, piperacillin, levofloxacin, and tetracycline. This method can quickly confirm the drug resistance of clinical diabetic foot infections, which can help aid in the early treatment of patients.

A matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) method (Mass-Fix) as a replacement for gel-based immunofixation (IFE) has been recently described. To utilize Mass-Fix clinically, a validated automated method was required. Our aim was to automate the pre-analytical processing, improve positive specimen identification and ergonomics, reduce paper data storage and increase resource utilization without increasing turnaround time.Serum samples were batched and loaded onto a liquid handler along with reagents and a barcoded sample plate. The pre-analytical steps included: (1) Plating immunopurification beads. (2) Adding 10 μl of serum. (3) Bead washing. (4) Eluting the immunoglobulins (Igs), and reducing to separate the heavy and light Ig chains. The resulting plate was transferred to a second low-volume liquid handler for MALDI plate spotting. MALDI-TOF mass spectra were collected. Integrated in-house developed software was utilized for sample tracking, driving data acquisition, data analysis, history tracking, and result reporting. A total of 1,029 residual serum samples were run using the automated system and results were compared to prior electrophoretic results.The automated Mass-Fix method was capable of meeting the validation requirements of concordance with IFE, limit of detection (LOD), sample stability and reproducibility with a low repeat rate. Automation and integrated software allowed a single user to process 320 samples in an 8 h shift. Software display facilitated identification of monoclonal proteins. Additionally, the process maintains positive specimen identification, reduces manual pipetting, allows for paper free tracking, and does not significantly impact turnaround time (TAT).Mass-Fix is ready for implementation in a high-throughput clinical laboratory. [ABSTRACT FROM AUTHOR]

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In the present paper the laboratory isolation and identification of Bordatella bronchiseptica, the causative agent of canine tracheobronhitis, is described. A dog which suffered persistent cough, loss of appetite and fever was previously unsucceffully treated with antibiotics, which is why nasal swabs were taken and sent for microbiological assessment. The isolation of the causative agent was performed on routinely used standard solid growth mediums. The final identification of the isolate was done with MALDI-TOF (matrix-assisted laser desorption/ionization - time of flight) and real-time PCR (polymerase chain reaction) assays. Therapy based on the results of the antibiogram lead to successful recovery. The necessity of cooperation of veterinary clinicians and veterinary microbiologists for timely and reliable identification of the microbe(s) and selection of antimicrobials based on the results of the susceptibility testing is emphasized. The significance of the collaboration between microbiological veterinary laboratories and those dealing with human material is underlined. These can provide precise identification of zoonotic agents.

Introduction: Microbial identification is important due to its impact on both the patient and public health, because the rapid and accurate diagnosis allows of correct antibiotic treatment and control of infection. Currently, clinical microbiology laboratories are undergoing significant changes due to the development of automation systems, which enables faster and more accurate diagnosis. These advances were possible due to technological progress and the search for new strategies that reduced the costs of these tools, making them more accessible. Objective: This study aimed to highlight the importance of the implantation of new and advanced technologies in microbiology laboratories. Methodology: A review of scientific literature was carried out in scientific databases. Development: Traditional techniques of microbiological diagnosis include direct methods such as staining methods and optical microscopy to indirect methods such as culture and biochemical tests. The main problem is the fact that these techniques take time to provide a response to the clinician and, in many cases, need well-trained technicians for the correct interpretation of the results. It is, therefore, becoming increasingly important to develop rapid and accurate techniques. The innovative techniques include molecular biology, immunoassays, and mass spectrometry. Final considerations: Access to new technologies makes it possible to solve diagnostic issues that are increasingly challenging and also contribute to the improvement of the clinical setting and public health. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop and evaluate matrix assisted LASER desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry imaging (MSI) of blood smear. Integrated light microscope and MALDI IT-TOF mass spectrometer, together with a matrix sublimation device, were used for analysis of blood smears coming from healthy male donors. Different blood plasma removal, matrix deposition, and instrumental settings were evaluated using the negative and positive ionization modes while agreement between the light microscopy images and the lateral distributions of cellular marker compounds served as the MSI quality indicator. Red and white blood cells chemical composition was analyzed using the differential m/z expression. Five seconds of exposure to ethanol followed by the 5 min of 9-aminoacridine or α-cyano-4-hydroxycinnamic acid deposition, together with two sets of instrumental settings, were selected for the MALDI TOF MSI experiments. Application of the thin and transparent matrix layers assured good correspondence between the LASER footprints and the preselected regions of interest. Cellular marker m/z signals coincided well with the appropriate cells. A metabolite databases search using the differentially expressed m/z produced hits which were consistent with the respective cell types. This study sets the foundations for application of blood smear MALDI TOF MSI in clinical diagnostics and research.

Identification and characterization of micro-organisms that cause infections are crucial for successful management of patients. For several decades, routine clinical microbiological diagnostic laboratories have been equipped with a growing panel of culture-dependent and culture-independent methods to investigate the microbial etiology of infectious diseases. Considering the disadvantages of traditional methods, multiplex PCR techniques have been routinely endorsed in clinical microbiology laboratories as rapid and sensitive diagnostic and prognostic tool including many PCR panels routinely used in microbial diagnostics. The great advance in medical biotechnology has been associated with development of Matrix-Associated Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI TOF MS). The power of MALDI TOF MS correctly identified 93.2% of organisms to the species level and 5.3% to the genus level. Recently, the application of next-generation sequencing (NGS) technology and its various methodological variants makes it possible to detect different types of microorganisms present within a microbial sample simultaneously, using a culture-independent approach and in a single sequencing run. Over the next 5 to 10 years, although it is unlikely to see NGS completely replacing the conventional culture and susceptibility methods, a wealth of NGS applications will be acquired in the vast majority of diagnostic microbiology laboratories worldwide, providing enhanced diagnostic capabilities and improving the quality of patients care. In Egyptian diagnostic microbiology laboratories, we have to ask ourselves; are we ready to subsist this new era? Sure the answer is: 'All things are ready, if our mind be so'. [ABSTRACT FROM AUTHOR]

Introduction: Laboratory surveillance of Streptococcus pneumoniae serotypes plays a crucial role in effectively implementing vaccines to prevent invasive pneumococcal diseases. The conventional method of serotyping, known as the Quellung reaction, is both time-consuming and expensive. However, the emergence of MALDI-TOF MS technology has revolutionized microbiology laboratories by enabling rapid and cost-effective serotyping based on protein profiles., Objectives: In this study, we aimed to investigate the viability of utilizing MALDI-TOF MS technology as an adjunctive and screening method for capsular typing of Streptococcus pneumoniae . Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates., Methods: Firstly, we established a comprehensive spectral database comprising isolates of serotypes present in the PCV13 vaccine, along with the top 10 most prevalent NON PCV13 serotypes based on local epidemiological data. This database served as a foundation for developing unsupervised models utilizing MALDI-TOF MS spectra, which enabled us to identify inherent patterns and relationships within the data. Our analysis involved a dataset comprising 215 new isolates collected from nationwide surveillance in Argentina. Our approach involved developing classification models based on MALDI-TOF MS to discern between Streptococcus pneumoniae strains originating from PCV13 (13-valent pneumococcal conjugate vaccine) and NON PCV13 isolates., Results: Although our findings revealed suboptimal performance in serotype classification, they provide valuable insights into the potential of machine learning algorithms in this context. The sensitivity of the models ranged from 0.41 to 0.46, indicating their ability to detect certain serotypes. The observed specificity consistently remained at 0.60, suggesting a moderate level of accuracy in identifying non-vaccine serotypes. These results highlight the need for further refinement and optimization of the algorithms to enhance their discriminative power and predictive accuracy in serotype identification.By addressing the limitations identified in this study, such as exploring alternative feature selection techniques or optimizing algorithm parameters, we can unlock the full potential of machine learning in robust and reliable serotype classification of S. pneumoniae . Our work not only provides a comprehensive evaluation of multiple machine learning models but also emphasizes the importance of considering their strengths and limitations., Conclusion: Overall, our study contributes to the growing body of research on utilizing MALDI-TOF MS and machine learning algorithms for serotype identification purposes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 THE AUTHORS.)

Background: Our objective was to determine the effect of the MALDI TOF on time to optimal antimicrobial therapy in bloodstream infections (BSI) compared to conventional methods. Methods: We reviewed all positive blood cultures from February 2012- 2014. The control group (CG) had pathogen identification using conventional methods and the intervention group (IG) with MALDI-TOF. Results: There were 199 cultures (CG, n=121, IG, n=78). The median time to species identification (hours) for the CG was 48, interquartile range (IQR) 37-57 vs. IG=17, IQR 14-23 (median difference 31, 95% Confidence Interval (CI) -38 to -25). Median time to optimal therapy (hours) for the CG was 28, IQR 2-64 vs. IG= 14.5, IQR 3-55 (median difference -13.5, 95% CI -31-13). By Cox regression MALDI TOF was not associated with reduced time to optimal therapy (hazard ratio (HR) 1.2, p=0.64). Conclusions: Species level identification is faster with MALDI TOF in BSI but does not allow for faster time to optimal antimicrobials. [ABSTRACT FROM AUTHOR]

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The controlled functionalization of polymers via anionic polymerization draws great attention not only because of the importance of introducing functionality into otherwise unfunctionalized polymers, but also because of the possibility to use the resulting macromonomers to make a variety of complex architectures. The versatile family of 1,1-diphenylethylene (DPE) derivatives is widely used to produce many different functionalized (co)polymers. DPE can be added either as an end-capping agent or be activated by butyllithium to initiate the polymerization. However, each approach faces potential problems in gaining precise control over the number of DPE moieties per chain. In this work, for the first time, the effectiveness of each approach is compared by the characterization of 1,1-bis(4- tert-butyldimethylsiloxyphenyl)ethylene functionalized polystyrene, synthesized via both the procedures. A combination of NMR, size exclusion chromatography, matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry, and interaction chromatography is used. To overcome the limitations of DPE derivatives, the use of a novel (protected) bisphenol F potassium initiator is proposed. [ABSTRACT FROM AUTHOR]

The induction of plant immunity by Pathogen Associated Molecular Patterns (PAMPs) constitutes a powerful strategy for crop protection. PAMPs indeed induce general defense responses in plants and thus increase plant resistance to pathogens. Phytophthora infestans culture filtrates (CCFs) are known to induce defense responses and decrease the severity of soft rot due to Pectobacterium atrosepticum in potato tubers. The aim of this study was to identify and characterize the active compounds from P. infestans filtrate. The filtrate was fractionated by gel filtration, and the protection effects against P. atrosepticum and the ability to induce PAL activity were tested for each fraction. The fraction active in protection (F1) also induced PAL activity, as did the whole filtrate. Three elicitins (INF1, INF4 and INF5) were identified in F1b, subfraction of F1, by MALDI-TOF-MS and MS/MS analyses. However, deproteinized F1b still showed biological activity against the bacterium, revealing the presence of an additional active compound. GC-MS analyses of the deproteinized fraction highlighted the presence of a galactan-based complex polysaccharide. These experiments demonstrate that the biological activity of the CCF against P. atrosepticum results from a combined action of three elicitins and a complex polysaccharide, probably through the activation of general defense responses.

BACKGROUND: Liver regeneration (LR) after 2/3 partial hepatectomy (PH) is one of the most studied models of cell, organ, and tissue regeneration. Although the transcriptional profile analysis of regenerating liver has been carried out by many reserachers, the dynamic protein expression profile during LR has been rarely reported up to date. Therefore, this study aims to detect the global proteomic profile of the regenerating rat liver following 2/3 hepatectomy, thereby gaining some insights into hepatic regeneration mechanism. RESULTS: Protein samples extracted from the sham-operated and the regenerating rat livers at 6, 12, 24, 72, 120 and 168 h after PH were separated by IEF/SDS-PAGE and then analyzed by MALDI-TOF/TOF mass spectrometry. Compared to sham-operated groups, there were totally 220 differentially expressed proteins (including 156 up-regulated, 62 down-regulated, and 2 up/down-regulated ones) identified in the regenerating rat livers, and most of them have not been previously related to liver regeneration. According to the expression pattern analysis combined with gene functional analysis, it showed that lipid and carbohydrate metabolism were enhanced at the early phase of LR and continue throughout the regeneration process. Ingenuity Pathway Analysis indicated that YWHAE protein (one of members of the 14-3-3 protein family) was located at the center of pathway networks at all the timepoints after 2/3 hepatectomy under our experimental conditions, maybe suggesting a central role of this protein in regulating liver regeneration. Additionally, we also revealed the role of Cdc42 (cell division cycle 42) in the termination of LR. CONCLUSIONS: For the first time, our proteomic analysis suggested an important role of YWHAE and pathway mediated by this protein in liver regeneration, which might be helpful in expanding our understanding of LR amd unraveling the mechanisms of LR.

Thermal decomposition of dinitrotoluene (DNT) isomers and formed products were studied. Initial stage of thermal decomposition was the field of interests because decomposition of even a few percent of a substance may cause hazard. The generation of impurities at the initial stage of decomposition was examined on the basis of the decrease of the original substance melting enthalpy and the increase of impurities fraction determined with cryometric method. MALDI TOF was used as the independent method of formed compounds molar masses determination. Samples of DNT isomers at raised temperature (up till 480 K) undergo aggregation leading to macromolecular substances. Regardless the substituents position, the initial phase of decomposition leads to same intermediate products. Mass spectra of DNT isomers thermally conditioned contain strong signals m/ z, among others, 688, 1063, 1137, 1211. Thermogravimetric analysis revealed that observed difficulties with studying the decomposition initial stage are related to high vapor pressure below decomposition temperature, what especially concerns 2,6-DNT isomer. [ABSTRACT FROM AUTHOR]

Canastra cheese is a cheese with geographical indication recognized by the Brazilian National Institute of Industrial Protection under number IG201002. It is produced in seven municipalities in the state of Minas Gerais in a region called Serra da Canastra. In this work, samples of milk, “pingo” (natural starter), whey and Canastra cheese were collected on a farm in Medeiros-MG/Brazil to evaluate the yeast microbiota and select yeasts for whey fermentation to produce ethanol and volatile aromatic compounds of relevance in the production of cheese. Thirty-nine isolates capable of fermenting lactose in a synthetic medium were identified by MALDI-TOF as Kluyveromyces lactis (29), Torulaspora delbrueckii (7) and Candida intermedia (3). Eleven isolates of K. lactis and three of T. delbrueckii efficiently fermented lactose until 4th day, and due to this reason were selected for cheese whey fermentation with Brix 12, 14 and 18. Generally, the isolates T. delbrueckii B14, B35, and B20 and K. lactis B10 were the most effective regardless of the initial Brix value. The identification of these four isolates by MALDI TOF was confirmed by sequencing of the ITS region. In the fermentation of cheese whey 14 Brix, T. delbrueckii B14 and B35, respectively yielded 24.06 g/L and 16.45 g/L of ethanol, while K. lactis B10 was more efficient in the consumption of lactose. In sequential culture with K. lactis B10 inoculated 48 h after T. delbrueckii B14, 97.82% of the total sugars were consumed resulting in the production of 19.81 g/L ethanol and 39 aromatic volatile compounds. The most abundant compounds were 3-methyl-1-butanol, octanoic acid and ethyl decanoate, which are reported as important for the aroma and flavor of cheeses. Based in our results, B10 isolate inoculated 48 h after B14 isolate is a promising yeast inoculum to be used for fermentation of dairy substrates. [ABSTRACT FROM AUTHOR]

Mechanisms of coke formation and growth transformation on MOR zeolite were investigated using a microbalance at 623 K for two propene pressures: 0.1 and 1 bar. The low and high coking pressures correspond to laboratory and industrial conditions, respectively. Initial coke deposition is faster at high pressure, but the maximum uptake is higher at low pressure. The complete determination of chemical composition of coke has required the use of a lot of techniques (IRFT, GC–MS, MALDI-TOF). From the change of chemical composition of coke, it can be proposed by different mechanisms of growth of coke molecules trapped in the zeolite micropores. The coke grows under industrial conditions (high olefins pressure) by successive alkylation/cyclization/aromatization reactions, while under laboratory conditions (low olefins pressure) the growth proceeds preferentially by condensation of coke molecules. [ABSTRACT FROM AUTHOR]

We describe a MALDI-TOF ion detector based on freestanding silicon nanomembrane technology. The detector is tested in a commercial MALDI-TOF mass spectrometer with equimolar mixtures of proteins. The operating principle of the nanomembrane detector is based on phonon-assisted field emission from these silicon nanomembranes, in which impinging ion packets excite electrons in the nanomembrane to higher energy states. Thereby the electrons can overcome the vacuum barrier and escape from the surface of the nanomembrane via field emission. Ion detection is demonstrated of apomyoglobin (16,952 Da), aldolase (39,212 Da), bovine serum albumin (66,430 Da), and their equimolar mixtures. In addition to the three intact ions, a large number of fragment ions are also revealed by the silicon nanomembrane detector, which are not observable with conventional detectors.

Ixodes ricinus is vector in the transmission of many important infectious diseases in human and animals. There is still minimal information available on the bacterial agents associated with ticks found in Slovakia. We performed a survey of the bacterial communities associated with Ixodes ricinus collected from forest area near a great city aglomeration. Bacterial 16S rRNA hypervariable region amplicon libraries prepared from the Ixodes ricinus females were sequenced on Illumina MiSeq platform. We detected a total of 107 bacterial genera and order Clostridiales and class Bacilli (with more than 100 reads). Dominant taxa included the tick endosymbionts e.g. spotted fever group (Rickettsia 21998 reads) and Coxiella (10715 reads). Second dominant species was mycoplasma Spiroplasma ixodetis (9554 reads). Dominant enviromental soil bacteria were Pseudomonas (6741 reads), Nocardiodes (4753 reads), Brevundimonas (2797 reads), Devosia (2797 reads) Aureimonas (1398 reads), Actinomycetospora (964 reads), Terrimonas (962 reads), Pedobacter (1139 reads), Methylobacterium (956 reads), Rhodococcus (945 reads), Williamsia (832 reads), Rhizobium (787 reads), Mesorhizobium (631 reads), Rhizobium (602 reads) and Spirosoma (486 reads) . Firmicutes were only 280 reads with 151 reads of Clostridia and 128 reads of Bacilli (include Staphylococcus and Bacillus ). The cultivation and Maldi Tof analysis revealed seven species of coagulase negative staphylococci (CoNS) i.e., Staphylococcus epidermidis, S. capitis, S.haemolyticus, S.hominis, S. pasteuri, S.chromogenes, S.warneri and Micrococcus luteus. Antibiotic resistant CoNS with msrA and blaZ genes were detected. Five species of bacilli i.e. Bacillus cereus, B. licheniformis, B. thuringiensis and B. mycoides and two species of Brevibacillus i.e. B. parabrevis and B. agri were detected by Maldi Tof, also. The results of the next generation sequencing revealed a new look at the complexity of the Ixodes ricinus microbiome. [ABSTRACT FROM AUTHOR]

The reaction of citric acid with wood veneers was studied by Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CP MAS 13C NMR) and matrix assisted laser desorption ionization time of flight (MALDI ToF) mass spectrometry. The analysis showed that reactions of citric acid occurred with both lignin and carbohydrate constituents of wood. The reactions occurring are esterifications between the carboxylic acid functions of citric acid and the numerous aromatic and aliphatic hydroxyl groups of the main wood constituents. Reaction of citric acid with glucose as a simple model compound of carbohydrates hydroxyl groups also yielded reactions leading to linear and branched oligomers by esterification. The result indicate that the reactions of esterification are accompanied in parallel by some internal rearrangements of lignin. The applied results on bonding wide flat wood surfaces such as veneers to obtain LVL panels yielded excellent strength results even if the conditions of pressing were more drastic than what is usual for this application. The applied bonding results have shown that citric acid has great potential to be used as a bio-binder for wood veneers.

The main goal of this study was to produce cachaça using a mixed inoculum of Saccharomyces cerevisiae and Meyerozyma caribbica and characterize the produced beverage using HPLC, GC–FID, GC–MS and sensorial analysis. Additionally, the use of MALDI-TOF as a tool to characterize and monitor pure and mixed inocula fermenting sugar cane juice was also evaluated. Vat fermentations were carried out for three consecutive batches using autoclaved 16 °Brix sugar cane juice fermented by a mixed inoculum of M. caribbica 10 7 cells/mL and S. cerevisiae 10 8 cells/mL. The cachaça produced by the mixed culture of M. caribbica and S. cerevisiae showed the highest concentration of volatile compounds associated with good sensory descriptors such as ethyl hexanoate (114.11 μg/L), 2-phenylethyl acetate (2.77 μg/L), a-terpineol (0.45 μg/L), b-citronellol (2.47 μg/L), and geraniol (0.24 μg/L). This beverage consequently showed greater acceptance in the sensorial analysis for taste and aroma, especially by younger panelists. The feasibility of MALDI-TOF use under studied conditions was demonstrated by the comparison of the results obtained from yeast cultivation in YPD broth, YPD agar and sugar cane juice, showing that there was no interference of sugar cane juice in protein profile. The results obtained from MALDI-TOF analysis showed that the protein extraction directly from sugar cane juice under fermentation, without the traditional plating step, allowed the distinction between mixed and pure inocula even under different M. caribbica populations and Brix degrees. [ABSTRACT FROM AUTHOR]

2,3-Dinitrotoluene (2,3-DNT) thermal decomposition and its products were studied. Main attention was paid on the initial stage of decomposition, because the degradation of even a few percent of high energetic compound may cause significant hazard. Partial decomposition of 2,3-DNT was performed conditioning at the temperature range of 457-568 K. Impurities production at the initial stage of decomposition was determined by the analysis of melting enthalpy decrease with cryometric method. Mean self-aggregation number of the initial substance was defined and determined to estimate the molecular mass of products of 2,3-DNT thermal conditioning. MALDI TOF method was used for independent molecular mass verification. 2,3-DNT is thermally stable substance. Heating of its sample from the ambient temperature to 486 K with the heating rate of 2 K min does not cause thermal decomposition. Very good reproducibility of melting process performed on the same sample was obtained. Only prolonged conditioning at raised temperature leads to initial substance loss. Two competitive reactions, aggregation and decomposition, were run during 2,3-DNT thermal conditioning. Heating with low heating rate leads to products with higher molecular masses. Two different results prove that: MALDI TOF analysis and the melting enthalpy decrease which is higher than the increase in impurities content determined with cryometric method. Mass spectrum of the thermally conditioned 2,3-DNT samples includes strong signals with (among others) following m/ z values: 551, 687, 1062, 1137, 1211. Formed macromolecular compounds were stable until the temperature of 500 K. [ABSTRACT FROM AUTHOR]

Poly(phenylsilsesquioxanes) of regular ladder like structure were synthesized by condensation of [PhSi(O)OH] 4 obtained in situ from sodium cyclosiloxanolate {(Na + ) 4 [PhSi(O)O − ] 4 } nL (L = iPrOH, H 2 O). The composition of oligomers present in the reaction mixture was analysed with MALDI ToF during the course of polycondensation. Redistribution of siloxane bonds and cyclization of macromolecules were detected. Cyclic LPSQ-Ph species and silsesquioxane redistribution in basic medium was also observed for oligo(phenylsilsesquioxanes) obtained by stepwise coupling polymerization. TGA and FTIR analysis of thermal decomposition process indicated significant differences in the course of structural rearrangements at high temperatures for both types of polysilsesquioxanes. [ABSTRACT FROM AUTHOR]

The effect of acidic ionic liquid (IL) as a new catalyst on the properties of wood-based panels bonded with urea-glyoxal (UG) resins was investigated. Different levels of N-methyl-2-pyrrolidone hydrogen sulfate ([HNMP] HSO4 (0, 1, 2, 3 wt %)) were added to prepared UG resin. The resin was then used for preparing laboratory particleboard panels. Then, the properties of the prepared panels were evaluated. The structure of the prepared UG resin was studied by 13C NMR, and thermal curing behavior of the resin before and after the addition of IL was measured by DSC. Additionally, the main oligomers formed in the UG reaction were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectroscopy. The results indicated that IL can be used as an efficient catalyst for UG resin. The physicochemical tests indicated that the addition of [HNMP] HSO4 from 0 to 3 wt % decreased the pH value of the glue-mix, and the pH decreased on curing to the same level as urea-formaldehyde resins. The gel accelerated with increasing catalyst content and with the decreasing of the pH in the UG resin. The panels prepared with IL had higher mechanical strength and dimensional stability compared to those made from UG resins containing NH4Cl. Scanning electron microscope (SEM) micrographs showed that the panels prepared with ionic liquid presented low porous. DSC analysis showed that the addition of IL to the UG resin decrease the energy of activation of the curing reaction to render possible cross-linking. The MALDI TOF results indicated a preponderant linearity of the oligomers formed, implying a high energy of activation of curing for UG resins. [ABSTRACT FROM AUTHOR]

We demonstrate mechanical modulation of phonon-assisted field emission in a free-standing silicon nanomembrane detector for time-of-flight mass spectrometry of proteins. The impacts of ion bombardment on the silicon nanomembrane have been explored in both mechanical and electrical points of view. Locally elevated lattice temperature in the silicon nanomembrane, resulting from the transduction of ion kinetic energy into thermal energy through the ion bombardment, induces not only phonon-assisted field emission but also a mechanical vibration in the silicon nanomembrane. The coupling of these mechanical and electrical phenomenon leads to mechanical modulation of phonon-assisted field emission. The thermal energy relaxation through mechanical vibration in addition to the lateral heat conduction and field emission in the silicon nanomembrane offers effective cooling of the nanomembrane, thereby allowing high resolution mass analysis. [ABSTRACT FROM AUTHOR]

The ghrelin hormone is a 28 amino acid peptide esterified on serine 3 with octanoic acid. Ghrelin is inactivated by hydrolysis of the ester bond. Previous studies have relied on inhibitors to identify human butyrylcholinesterase (BChE) as the hydrolase in human plasma that converts ghrelin to desacyl ghrelin. The reaction of BChE with ghrelin is unusual because the rate of hydrolysis is very slow and the substrate is ten times larger than standard BChE substrates. These unusual features prompted us to re-examine the reaction, using human BChE preparations that were more than 98% pure. Conversion of ghrelin to desacyl ghrelin was monitored by MALDI TOF mass spectrometry. It was found that 5 different preparations of pure human BChE all hydrolyzed ghrelin, including BChE purified from human plasma, from Cohn fraction IV-4, BChE immunopurified by binding to monoclonals mAb2 and B2 18-5, and recombinant human BChE purified from culture medium. We reasoned that it was unlikely that a common contaminant that could be responsible for ghrelin hydrolysis would appear in all of these preparations. km was <1 μM, and kcat was ∼1.4 min −1 . A Michaelis–Menten analysis employing these kinetic values together with serum concentrations of ghrelin and BChE demonstrated that BChE could hydrolyze all of the ghrelin in serum in ∼1 h. It was concluded that BChE is physiologically relevant for the hydrolysis of ghrelin. [ABSTRACT FROM AUTHOR]

Since the emergence of proteomics methods, many proteins specific for renal cell carcinoma (RCC) have been identified. Despite their usefulness for the specific diagnosis of RCC, such proteins do not provide spatial information on the diseased tissue. Therefore, the identification of cancerspecific proteins that include information on their specific location is needed. Recently, matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) based imaging mass spectrometry (IMS) has emerged as a new tool for the analysis of spatial distribution as well as identification of either proteins or small molecules in tissues. In this report, surgical tissue sections of papillary RCC were analyzed using MALDI-IMS. Statistical analysis revealed several discriminative cancer-specific m/z-species between normal and diseased tissues. Among these m/z-species, two particular proteins, S100A11 and ferritin light chain, which are specific for papillary RCC cancer regions, were successfully identified using LC-MS/MS following protein extraction from independent RCC samples. The expressions of S100A11 and ferritin light chain were further validated by immunohistochemistry of human tissues and tissue microarrays (TMAs) of RCC. In conclusion, MALDI-IMS followed by LCMS/ MS analysis in human tissue identified that S100A11 and ferritin light chain are differentially expressed proteins in papillary RCC cancer regions. [ABSTRACT FROM AUTHOR]

Isosorbide and isomannide are polycondensed in solution with trimesoyl chloride at a concentration of 0.06 mol L−1 for the synthesis of cyclic and multicyclic polyesters. The feed ratio diol/trimesoyl chloride is varied from 1.0/1.0 to 1.6/1.0. As all obtained polyesters prove insoluble, innovative solvent-free matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI ToF MS) is performed for their characterization. The influence of the stereochemistry is shown to be of great importance for the cyclization trend. Both isosorbide and isomannide lead mainly to cyclic and multicyclic structures at a feed ratio of 1.0/1.0 and 1.1/1.0. Isomannide gives higher fractions of multicyclic structures. The products are characterized by complementary techniques such as 13C cross polarization magic angle spinning nuclear magnetic resonance (13C CP-MAS NMR) and differential scanning calorimetry measurements. Application as a cryptands for the uptake of metal ions in aqueous media is followed by inductively coupled plasma atomic emission spectroscopy (ICP AES) analysis and reveal efficient toward large range of metals with tunable selectivity depending on the starting diol. [ABSTRACT FROM AUTHOR]