Decellularization of Human Pancreatic Fragments with Pronounced Signs of Structural Changes.

A significant lack of donor organs restricts the opportunity to obtain tissue-specific scaffolds for tissue-engineering technologies. One of the acceptable solutions is the development of decellularization protocols for a human donor pancreas unsuitable for transplantation. A protocol of obtaining a biocompatible tissue-specific scaffold from decellularized fragments with pronounced human pancreas lipomatosis signs with preserved basic fibrillary proteins of a pancreatic tissue extracellular matrix was developed. The scaffold supports the adhesion and proliferation of human adipose derived stem cell (hADSCs) and prolongs the viability and insulin-producing function of pancreatic islets. Experiments conducted allow for the reliance on the prospects of using the donor pancreas unsuitable for transplantation in the technologies of tissue engineering and regenerative medicine, including the development of a tissue equivalent of a pancreas.

Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA.

DivIVA is a protein initially identified as a spatial regulator of cell division in the model organism Bacillus subtilis, but its homologues are present in many other Gram-positive bacteria, including Clostridia species. Besides its role as topological regulator of the Min system during bacterial cell division, DivIVA is involved in chromosome segregation during sporulation, genetic competence, and cell wall synthesis. DivIVA localizes to regions of high membrane curvature, such as the cell poles and cell division site, where it recruits distinct binding partners. Previously, it was suggested that negative curvature sensing is the main mechanism by which DivIVA binds to these specific regions. Here, we show that Clostridioides difficile DivIVA binds preferably to membranes containing negatively charged phospholipids, especially cardiolipin. Strikingly, we observed that upon binding, DivIVA modifies the lipid distribution and induces changes to lipid bilayers containing cardiolipin. Our observations indicate that DivIVA might play a more complex and so far unknown active role during the formation of the cell division septal membrane.

Incorporation of pentraxin 3 into hyaluronan matrices is tightly regulated and promotes matrix cross-linking.

Mammalian oocytes are surrounded by a highly hydrated hyaluronan (HA)-rich extracellular matrix with embedded cumulus cells, forming the cumulus cell·oocyte complex (COC) matrix. The correct assembly, stability, and mechanical properties of this matrix, which are crucial for successful ovulation, transport of the COC to the oviduct, and its fertilization, depend on the interaction between HA and specific HA-organizing proteins. Although the proteins inter-α-inhibitor (IαI), pentraxin 3 (PTX3), and TNF-stimulated gene-6 (TSG-6) have been identified as being critical for COC matrix formation, its supramolecular organization and the molecular mechanism of COC matrix stabilization remain unknown. Here we used films of end-grafted HA as a model system to investigate the molecular interactions involved in the formation and stabilization of HA matrices containing TSG-6, IαI, and PTX3. We found that PTX3 binds neither to HA alone nor to HA films containing TSG-6. This long pentraxin also failed to bind to products of the interaction between IαI, TSG-6, and HA, among which are the covalent heavy chain (HC)·HA and HC·TSG-6 complexes, despite the fact that both IαI and TSG-6 are ligands of PTX3. Interestingly, prior encounter with IαI was required for effective incorporation of PTX3 into TSG-6-loaded HA films. Moreover, we demonstrated that this ternary protein mixture made of IαI, PTX3, and TSG-6 is sufficient to promote formation of a stable (i.e. cross-linked) yet highly hydrated HA matrix. We propose that this mechanism is essential for correct assembly of the COC matrix and may also have general implications in other inflammatory processes that are associated with HA cross-linking.

Inter-α-inhibitor impairs TSG-6-induced hyaluronan cross-linking.

Under inflammatory conditions and in the matrix of the cumulus-oocyte complex, the polysaccharide hyaluronan (HA) becomes decorated covalently with heavy chains (HCs) of the serum glycoprotein inter-α-inhibitor (IαI). This alters the functional properties of the HA as well as its structural role within extracellular matrices. The covalent transfer of HCs from IαI to HA is catalyzed by TSG-6 (tumor necrosis factor-stimulated gene-6), but TSG-6 is also known as a HA cross-linker that induces condensation of the HA matrix. Here, we investigate the interplay of these two distinct functions of TSG-6 by studying the ternary interactions of IαI and TSG-6 with well defined films of end-grafted HA chains. We demonstrate that TSG-6-mediated cross-linking of HA films is impaired in the presence of IαI and that this effect suppresses the TSG-6-mediated enhancement of HA binding to CD44-positive cells. Furthermore, we find that the interaction of TSG-6 and IαI in the presence of HA gives rise to two types of complexes that independently promote the covalent transfer of heavy chains to HA. One type of complex interacts very weakly with HA and is likely to correspond to the previously reported covalent HC·TSG-6 complexes. The other type of complex is novel and binds stably but noncovalently to HA. Prolonged incubation with TSG-6 and IαI leads to HA films that contain, in addition to covalently HA-bound HCs, several tightly but noncovalently bound molecular species. These findings have important implications for understanding how the biological activities of TSG-6 are regulated, such that the presence or absence of IαI will dictate its function.

Adaptation of mycoplasmas to antimicrobial agents: Acholeplasma laidlawii extracellular vesicles mediate the export of ciprofloxacin and a mutant gene related to the antibiotic target.

This study demonstrated that extracellular membrane vesicles are involved with the development of resistance to fluoroquinolones by mycoplasmas (class Mollicutes). This study assessed the differences in susceptibility to ciprofloxacin among strains of Acholeplasma laidlawii PG8. The mechanisms of mycoplasma resistance to antibiotics may be associated with a mutation in a gene related to the target of quinolones, which could modulate the vesiculation level. A. laidlawii extracellular vesicles mediated the export of the nucleotide sequences of the antibiotic target gene as well as the traffic of ciprofloxacin. These results may facilitate the development of effective approaches to control mycoplasma infections, as well as the contamination of cell cultures and vaccine preparations.

Influence of the Ti-TiN-(Y,Ti,Al)N Nanolayer Coating Deposition Process Parameters on Cutting Tool Oxidative Wear during Steel Turning.

Ti-TiN-(Y,Ti,Al)N coatings with a three-layer architecture (adhesive Ti layer, transition TiN layer, and wear-resistant (Y,Ti,Al)N layer) were studied. When depositing coatings, three arc current values of the yttrium cathode were used: 65, 85, and 105 A. The yttrium contents in the coatings were 30, 47, and 63 at. %, respectively. When turning 1045 steel, a coating with 30 at. % yttrium showed better wear resistance compared to a commercial (Ti,Cr,Al)N coating. The coating with 63 at. % yttrium did not show an increase in wear resistance compared to the uncoated sample. Nanolayers with a high yttrium content are oxidized more actively compared to nanolayers with a high titanium content. Phase analysis shows partial retention of the initial phases (Y,Ti,Al)N and (Ti,Y,Al)N during the formation of the Y2O3 oxide phase in the outer layers of the coating and the presence of only the initial phases in the deep layers. Coating nanolayers with high contents of aluminum and yttrium lose their original structure to a greater extent during oxidation compared to layers without aluminum.

Information transfer in mammalian glycan-based communication.

Glycan-binding proteins, so-called lectins, are exposed on mammalian cell surfaces and decipher the information encoded within glycans translating it into biochemical signal transduction pathways in the cell. These glycan-lectin communication pathways are complex and difficult to analyze. However, quantitative data with single-cell resolution provide means to disentangle the associated signaling cascades. We chose C-type lectin receptors (CTLs) expressed on immune cells as a model system to study their capacity to transmit information encoded in glycans of incoming particles. In particular, we used nuclear factor kappa-B-reporter cell lines expressing DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN), macrophage C-type lectin (MCL), dectin-1, dectin-2, and macrophage-inducible C-type lectin (MINCLE), as well as TNFαR and TLR-1&2 in monocytic cell lines and compared their transmission of glycan-encoded information. All receptors transmit information with similar signaling capacity, except dectin-2. This lectin was identified to be less efficient in information transmission compared to the other CTLs, and even when the sensitivity of the dectin-2 pathway was enhanced by overexpression of its co-receptor FcRγ, its transmitted information was not. Next, we expanded our investigation toward the integration of multiple signal transduction pathways including synergistic lectins, which is crucial during pathogen recognition. We show how the signaling capacity of lectin receptors using a similar signal transduction pathway (dectin-1 and dectin-2) is being integrated by compromising between the lectins. In contrast, co-expression of MCL synergistically enhanced the dectin-2 signaling capacity, particularly at low-glycan stimulant concentration. By using dectin-2 and other lectins as examples, we demonstrate how signaling capacity of dectin-2 is modulated in the presence of other lectins, and therefore, the findings provide insight into how immune cells translate glycan information using multivalent interactions.

The inflammation-associated protein TSG-6 cross-links hyaluronan via hyaluronan-induced TSG-6 oligomers.

Tumor necrosis factor-stimulated gene-6 (TSG-6) is a hyaluronan (HA)-binding protein that plays important roles in inflammation and ovulation. TSG-6-mediated cross-linking of HA has been proposed as a functional mechanism (e.g. for regulating leukocyte adhesion), but direct evidence for cross-linking is lacking, and we know very little about its impact on HA ultrastructure. Here we used films of polymeric and oligomeric HA chains, end-grafted to a solid support, and a combination of surface-sensitive biophysical techniques to quantify the binding of TSG-6 into HA films and to correlate binding to morphological changes. We find that full-length TSG-6 binds with pronounced positive cooperativity and demonstrate that it can cross-link HA at physiologically relevant concentrations. Our data indicate that cooperative binding of full-length TSG-6 arises from HA-induced protein oligomerization and that the TSG-6 oligomers act as cross-linkers. In contrast, the HA-binding domain of TSG-6 (the Link module) alone binds without positive cooperativity and weaker than the full-length protein. Both the Link module and full-length TSG-6 condensed and rigidified HA films, and the degree of condensation scaled with the affinity between the TSG-6 constructs and HA. We propose that condensation is the result of protein-mediated HA cross-linking. Our findings firmly establish that TSG-6 is a potent HA cross-linking agent and might hence have important implications for the mechanistic understanding of the biological function of TSG-6 (e.g. in inflammation).

Medical Evacuation and Liquidation of the Medical-Sanitary Aftereffects in Crisis.

The following article was cleared for publication following peer review and upon the Editor-in-Chief's decision. The manuscript is an addition to the global health literature. The manuscript reads uneven in the current English version, but the topic and concepts presented are of global interest and add to the disaster planning, response, and recovery knowledge base.Crisis situations (CS) are, unfortunately, happening in present days in each world side. And in this case, medical evacuation (ME) becomes necessary to save human lives. The presented study is regarding the description and analysis of the phases, peculiarities, and perspectives of ME organization and development. The study characterized the inter-sectoral method of the planning, and realization of crisis outcomes liquidation is provided. Four main ways of the realization of approaches that could guarantee the development of the ME system were found. Also has been identified the number of main problems which the ME system faces. Among them are lack of personnel/equipment in the medical crews; high time of transportation; the noise pollution and vibration in time of evacuation by air; the infection and exposure risk of the evacuation aircrews in the places of mass destruction weapons usage; the organizational and legislative problems of the foreign citizens' evacuation; and ME of the persons from the oil and gas production places.

Spectroscopic study of antimicrobial peptides: Structure and functional activity.

Amphibians are a natural source of a large number of peptides with a wide range of functional activities. Here, a complex of spectroscopic methods including NMR-, FTIR-, CD-, and UV-spectroscopy was applied to characterize the structure and functional activity of megin-1, a peptide isolated from amphibian skin. The three-dimensional structure of two forms of the peptide was determined using solution NMR spectroscopy. Thermodynamic characteristics of the process of peptide transformation from linear to cyclic form were obtained. Antibacterial and antimycotic properties of the peptide, as well as its protease inhibitory activities, were analyzed.

In vitro reconstitution of Escherichia coli divisome activation.

The actin-homologue FtsA is essential for E. coli cell division, as it links FtsZ filaments in the Z-ring to transmembrane proteins. FtsA is thought to initiate cell constriction by switching from an inactive polymeric to an active monomeric conformation, which recruits downstream proteins and stabilizes the Z-ring. However, direct biochemical evidence for this mechanism is missing. Here, we use reconstitution experiments and quantitative fluorescence microscopy to study divisome activation in vitro. By comparing wild-type FtsA with FtsA R286W, we find that this hyperactive mutant outperforms FtsA WT in replicating FtsZ treadmilling dynamics, FtsZ filament stabilization and recruitment of FtsN. We could attribute these differences to a faster exchange and denser packing of FtsA R286W below FtsZ filaments. Using FRET microscopy, we also find that FtsN binding promotes FtsA self-interaction. We propose that in the active divisome FtsA and FtsN exist as a dynamic copolymer that follows treadmilling filaments of FtsZ.

Real-time monitoring of peptidoglycan synthesis by membrane-reconstituted penicillin-binding proteins.

Peptidoglycan is an essential component of the bacterial cell envelope that surrounds the cytoplasmic membrane to protect the cell from osmotic lysis. Important antibiotics such as ß-lactams and glycopeptides target peptidoglycan biosynthesis. Class A penicillin-binding proteins (PBPs) are bifunctional membrane-bound peptidoglycan synthases that polymerize glycan chains and connect adjacent stem peptides by transpeptidation. How these enzymes work in their physiological membrane environment is poorly understood. Here, we developed a novel Förster resonance energy transfer-based assay to follow in real time both reactions of class A PBPs reconstituted in liposomes or supported lipid bilayers and applied this assay with PBP1B homologues from Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii in the presence or absence of their cognate lipoprotein activator. Our assay will allow unravelling the mechanisms of peptidoglycan synthesis in a lipid-bilayer environment and can be further developed to be used for high-throughput screening for new antimicrobials.

Data on proteomic profiling of extracellular vesicles of Acholeplasma laidlawii strains with increased resistance to antibiotics of different classes - ciprofloxacin and tetracycline.

To elucidate the regularities of adaptation of the representatives of class Mollicutes to antimicrobials and to identify the promising targets for eradication of mycoplasma infections and contaminations the comparative analysis of the molecular basis of bacterial resistance to antibiotics of different classes is needed. Previously, we presented the data on the whole-genome sequences of Acholeplasma laidlawii strains with different susceptibility to ciprofloxacin (GenBank: LXYB00000000.1), tetracycline (GenBank: NELO00000000.2) and melittin (GenBank: NELN00000000.2) as well as the data on cell and extracellular vesicle proteomes of melittin-resistant A. laidlawii strain [1]. The lists of extracellular vesicle proteins secreted by A. laidlawii strains with the increased resistance to ciprofloxacin (PG8R10) and tetracycline (PG8RTet) are presented here. The vesicle proteome profiles were obtained by 1D SDS-PAGE and liquid chromatography-mass spectrometry.

Data on the genome and proteome profiles of ciprofloxacin-resistant Acholeplasma laidlawii strains selected under different conditions in vitro.

Acholeplasma laidlawii is widespread hypermutable bacteria (class Mollicutes) capable of infecting humans, animals, plants, which is the main contaminant of cell cultures and vaccine preparations. The mechanisms of the development of antimicrobial resistance of this bacterium are associated with the secretion of extracellular vesicles, which can mediate the lateral transfer of antibiotic resistance determinants. We compared the genome profiles of ciprofloxacin-resistant A.laidlawii strains PG8r1 (MIC 10 µg/ml) and PG8r3 (MIC 10 µg/ml) selected under different in vitro conditions - when ciprofloxacin-sensitive (MIC 0.5 µg/ml) A.laidlawii PG8B strain was cultured at increasing concentrations of ciprofloxacin in a broth medium alone, and with vesicles derived from the ciprofloxacin-resistant (MIC 20 µg/ml) A.laidlawii PG8R10c-2 strain, respectively. Genome profiles of PG8c-3 (obtained from a single colony of the strain PG8B) and PG8R10c-2 were analyzed too. Patterns of the quinolone target genes (gyrA, gyrB, parE, parC) containing in extracellular vesicles of PG8c-3, PG8R10c-2, PG8r1 and PG8r3 were determined. Genome sequencing was performed on the NextSeq Illumina platform. Search and annotation of single nucleotide polymorphisms were performed using Samtools and SnpEff, respectively. We also compared cellular proteomes of PG8c-3, PG8r1 and PG8r3. The cellular proteome profiles of the A. laidlawii strains were determined by two-dimensional gel electrophoresis and MALDI-TOF/TOF MS. This work presents data on single nucleotide polymorphisms (SNPs) found in the genomes of the ciprofloxacin-resistant strains selected under different in vitro conditions and proteins that were differentially expressed in the cells of ciprofloxacin-resistant strains selected under different conditions in vitro.

Diffusion and capture permits dynamic coupling between treadmilling FtsZ filaments and cell division proteins.

Most bacteria accomplish cell division with the help of a dynamic protein complex called the divisome, which spans the cell envelope in the plane of division. Assembly and activation of this machinery are coordinated by the tubulin-related GTPase FtsZ, which was found to form treadmilling filaments on supported bilayers in vitro1, as well as in live cells, in which filaments circle around the cell division site2,3. Treadmilling of FtsZ is thought to actively move proteins around the division septum, thereby distributing peptidoglycan synthesis and coordinating the inward growth of the septum to form the new poles of the daughter cells4. However, the molecular mechanisms underlying this function are largely unknown. Here, to study how FtsZ polymerization dynamics are coupled to downstream proteins, we reconstituted part of the bacterial cell division machinery using its purified components FtsZ, FtsA and truncated transmembrane proteins essential for cell division. We found that the membrane-bound cytosolic peptides of FtsN and FtsQ co-migrated with treadmilling FtsZ-FtsA filaments, but despite their directed collective behaviour, individual peptides showed random motion and transient confinement. Our work suggests that divisome proteins follow treadmilling FtsZ filaments by a diffusion-and-capture mechanism, which can give rise to a moving zone of signalling activity at the division site.

Comparative Analysis of Approaches and Treatment Results of Patients with Early and Nonearly Rheumatoid Arthritis.

The article presents the results of a comparative analysis of different therapy regimens impact on the effectiveness of treatment of patients with early and late rheumatoid arthritis in steady-state. Data on ongoing basis anti-inflammatory therapy of rheumatoid arthritis and the treatment of associated conditions were obtained by continuous copying from case histories of hospital department patients. The observations lasted 12 months. The activity of rheumatoid arthritis before and after the treatment was determined by the DAS 28 (Disease Activity Score) index. The treatment results were evaluated as per the laboratory research and the DAS 28 index, including the counting of painful and swollen joints, erythrocyte sedimentation rate, and health assessment of the patient on a visual analogue scale.

An integrated assay to probe endothelial glycocalyx-blood cell interactions under flow in mechanically and biochemically well-defined environments.

Cell-cell and cell-glycocalyx interactions under flow are important for the behaviour of circulating cells in blood and lymphatic vessels. However, such interactions are not well understood due in part to a lack of tools to study them in defined environments. Here, we develop a versatile in vitro platform for the study of cell-glycocalyx interactions in well-defined physical and chemical settings under flow. Our approach is demonstrated with the interaction between hyaluronan (HA, a key component of the endothelial glycocalyx) and its cell receptor CD44. We generate HA brushes in situ within a microfluidic device, and demonstrate the tuning of their physical (thickness and softness) and chemical (density of CD44 binding sites) properties using characterisation with reflection interference contrast microscopy (RICM) and application of polymer theory. We highlight the interactions of HA brushes with CD44-displaying beads and cells under flow. Observations of CD44+ beads on a HA brush with RICM enabled the 3-dimensional trajectories to be generated, and revealed interactions in the form of stop and go phases with reduced rolling velocity and reduced distance between the bead and the HA brush, compared to uncoated beads. Combined RICM and bright-field microscopy of CD44+ AKR1 T-lymphocytes revealed complementary information about the dynamics of cell rolling and cell morphology, and highlighted the formation of tethers and slings, as they interacted with a HA brush under flow. This platform can readily incorporate more complex models of the glycocalyx, and should permit the study of how mechanical and biochemical factors are orchestrated to enable highly selective blood cell-vessel wall interactions under flow.

Glycosaminoglycans in extracellular matrix organisation: are concepts from soft matter physics key to understanding the formation of perineuronal nets?

Conventional wisdom has it that proteins fold and assemble into definite structures, and that this defines their function. Glycosaminoglycans (GAGs) are different. In most cases the structures they form have a low degree of order, even when interacting with proteins. Here, we discuss how physical features common to all GAGs-hydrophilicity, charge, linearity and semi-flexibility-underpin the overall properties of GAG-rich matrices. By integrating soft matter physics concepts (e.g. polymer brushes and phase separation) with our molecular understanding of GAG-protein interactions, we can better comprehend how GAG-rich matrices assemble, what their properties are, and how they function. Taking perineuronal nets (PNNs)-a GAG-rich matrix enveloping neurons-as a relevant example, we propose that microphase separation determines the holey PNN anatomy that is pivotal to PNN functions.

Antimicrobial resistance in mollicutes: known and newly emerging mechanisms.

This review is devoted to the mechanisms of antibiotic resistance in mollicutes (class Bacilli, subclass Mollicutes), the smallest self-replicating bacteria, that can cause diseases in plants, animals and humans, and also contaminate cell cultures and vaccine preparations. Research in this area has been mainly based on the ubiquitous mollicute and the main contaminant of cell cultures, Acholeplasma laidlawii. The omics technologies applied to this and other bacteria have yielded a complex picture of responses to antimicrobials, including their removal from the cell, the acquisition of antibiotic resistance genes and mutations that potentially allow global reprogramming of many cellular processes. This review provides a brief summary of well-known resistance mechanisms that have been demonstrated in several mollicutes species and, in more detail, novel mechanisms revealed in A. laidlawii, including the least explored vesicle-mediated transfer of short RNAs with a regulatory potency. We hope that this review highlights new avenues for further studies on antimicrobial resistance in these bacteria for both a basic science and an application perspective of infection control and management in clinical and research/production settings.

Genome Sequences of Acholeplasma laidlawii Strains with Increased Resistance to Tetracycline and Melittin.

Acholeplasma laidlawii is a well-suited model for studying the molecular basis for adapting mollicutes to environmental conditions. Here, we present the whole-genome sequences of two strains of A. laidlawii with increased resistance to tetracycline and melittin.