Межфазный катализ: синтез гликозильных эфиров N-ацетилглюкозамина

В межфазной системе “твердое тело — органический растворитель” в присутствии каталитических количеств 15-краун-5 перацетат α-D-глюкозаминилхлорида легко образует гликозильные эфиры ряда карбоновых кислот. Полученные 1-0-β-ацилпиранозы идентифицированы с помощью ¹Н ЯМР спектроскопии.У міжфазній системі “тверде тіло — органічний розчинник” у присутності каталітичної кількості 15-краун-5 перацетат α-D-глюкозамінілхлориду легко утворює глікозильні естери ряду карбонових кислот. Отримані 1-O-β-ацилпіранози ідентифіковані за допомогою ¹Н ЯМР-спектроскопії.Peracetate of α-D-glucosaminyl chloride forms easily the N-acetylglucosamine glycosyl esters of the carboxylic acids range in the phase transfer system of “solid-organic solvent” in the presence of catalytic amounts of 15-crown-5. The structure of 1-O-β-acylpyranose synthesized was identified by ¹H NMR spectroscopy

Developmental regulation of chicken surfactant protein A and its localization in lung

AbstractSurfactant Protein A (SP-A) is a collagenous C-type lectin (collectin) that plays an important role in the early stage of the host immune response. In chicken, SP-A (cSP-A) is expressed as a 26 kDa glycosylated protein in the lung. Using immunohistochemistry, cSP-A protein was detected mainly in the lung lining fluid covering the parabronchial epithelia. Specific cSP-A producing epithelial cells, resembling mammalian type II cells, were identified in the parabronchi. Gene expression of cSP-A markedly increased from embryonic day 14 onwards until the time of hatch, comparable to the SP-A homologue chicken lung lectin, while mannan binding lectin and collectins CL-L1 and CL-K1 only showed slightly changed expression during development. cSP-A protein could be detected as early as ED 18 in lung tissue using Western blotting, and expression increased steadily until day 28 post-hatch. Our observations are a first step towards understanding the role of this protein in vivo

Тоталітарні режими: ідеологічне обґрунтування цілей, форм і методів володарювання

Розглянуто теоретичні аспекти взаємовпливу ідеології та конкретно-історичних форм володарювання на прикладі фашизму і націонал-соціалізму. Проаналізована сутність праворадикальної ідеології, причини її виникнення, форми впливу та можливі загрози у контексті демократичного розвитку.The article researches the theoretical aspects of the mutual influence of an ideology and particular-historical forms of reigning on the Fascism's and the National-Socialism's example. The author analyzes the essence of right- radical ideology, the reasons of its appearance, forms of its influence as well as probable threats in the context of democratic development

The interplay between salmonella and intestinal innate immune cells in chickens

Salmonellosis is a common infection in poultry, which results in huge economic losses in the poultry industry. At the same time, Salmonella infections are a threat to public health, since contaminated poultry products can lead to zoonotic infections. Antibiotics as feed additives have proven to be an effective prophylactic option to control Salmonella infections, but due to resistance issues in humans and animals, the use of antimicrobials in food animals has been banned in Europe. Hence, there is an urgent need to look for alternative strategies that can protect poultry against Salmonella infections. One such alternative could be to strengthen the innate immune system in young chickens in order to prevent early life infections. This can be achieved by administration of immune modulating molecules that target innate immune cells, for example via feed, or by in-ovo applications. We aimed to review the innate immune system in the chicken intestine; the main site of Salmonella entrance, and its responsiveness to Salmonella infection. Identifying the most important players in the innate immune response in the intestine is a first step in designing targeted approaches for immune modulation.The Punjab Educational Endowment Fund, Punjab, Pakistan.https://www.mdpi.com/journal/pathogensam2022Veterinary Tropical Disease

Perforin and granzyme A release as novel tool to measure NK cell activation in chickens

Natural killer (NK) cells are cytotoxic lymphocytes that are present in the circulation but also in many organs including spleen and gut, where they play an important role in the defense against infections. Interaction of NK cells with target cells leads to degranulation, which results in the release of perforin and granzymes in the direct vicinity of the target cell. Chicken NK cells have many characteristics similar to their mammalian counterparts and based on similarities with studies on human NK cells, surface expression of CD107 was always presumed to correlate with granule release. However, proof of this degranulation or in fact the actual presence of perforin (PFN) and granzyme A (GrA) in chicken NK cells and their release upon activation is lacking. Therefore, the purpose of the present study was to determine the presence of perforin and granzyme A in primary chicken NK cells and to measure their release upon degranulation, as an additional tool to study the function of chicken NK cells. Using human specific antibodies against PFN and GrA in fluorescent and confocal microscopy resulted in staining in chicken NK cells. The presence of PFN and GrA was also confirmed by Western blot analyses and its gene expression by PCR. Stimulation of NK cells with the pectin SPE6 followed by flow cytometry resulted in reduced levels of intracellular PFN and GrA, suggesting release of PFN and GrA. Expression of PFN and GrA reversely correlated with increased surface expression of the lysosomal marker CD107. Finally it was shown that the supernatant of activated NK cells, containing the NK cell granule content including PFN and GrA, was able to kill Escherichia coli. This study correlates PFN and GrA release to activation of chicken NK cells and establishes an additional tool to study activity of cytotoxic lymphocytes in chickens

Host defence peptides identified in human apolipoprotein B as promising antifungal agents

Therapeutic options to treat invasive fungal infections are still limited. This makes the development of novel antifungal agents highly desirable. Naturally occurring antifungal peptides represent valid candidates, since they are not harmful for human cells and are endowed with a wide range of activities and their mechanism of action is different from that of conventional antifungal drugs. Here, we characterized for the first time the antifungal properties of novel peptides identified in human apolipoprotein B. ApoB-derived peptides, here named r(P)ApoBLPro, r(P)ApoBLAla and r(P)ApoBSPro, were found to have significant fungicidal activity towards Candida albicans (C. albicans) cells. Peptides were also found to be able to slow down metabolic activity of Aspergillus niger (A. niger) spores. In addition, experiments were carried out to clarify the mechanism of fungicidal activity of ApoB-derived peptides. Peptides immediately interacted with C. albicans cell surfaces, as indicated by fluorescence live cell imaging analyses, and induced severe membrane damage, as indicated by propidium iodide uptake induced upon treatment of C. albicans cells with ApoB-derived peptides. ApoB-derived peptides were also tested on A. niger swollen spores, initial hyphae and branched mycelium. The effects of peptides were found to be more severe on swollen spores and initial hyphae compared to mycelium. Fluorescence live cell imaging analyses confirmed peptide internalization into swollen spores with a consequent accumulation into hyphae. Altogether, these findings open interesting perspectives to the application of ApoB-derived peptides as effective antifungal agents

Avian surfactant protein (SP)-A2 first arose in an early tetrapod before the divergence of amphibians and gradually lost the collagen domain

The air-liquid interface of the mammalian lung is lined with pulmonary surfactants, a mixture of specific proteins and lipids that serve a dual purpose-enabling air-breathing and protection against pathogens. In mammals, surfactant proteins A (SP-A) and D (SP -D) are involved in innate defence of the lung. Birds seem to lack the SP-D gene, but possess SP-A2, an additional SP-A-like gene. Here we investigated the evolution of the SP-A and SP-D genes using computational gene prediction, homology, simulation modelling and phylogeny with published avian and other vertebrate genomes. PCR was used to confirm the identity and expression of SP-A analogues in various tissue homogenates of zebra finch and turkey. In silico analysis confirmed the absence of SP-D-like genes in all 47 published avian genomes. Zebra finch and turkey SP-A1 and SP-A2 sequences, confirmed by PCR of lung homogenates, were compared with sequenced and in silico predicted vertebrate homologs to construct a phylogenetic tree. The collagen domain of avian SP-A1, especially that of zebra finch, was dramatically shorter than that of mammalian SP-A. Amphibian and reptilian genomes also contain avian-like SP-A2 protein sequences with a collagen domain. NCBI Gnomon-predicted avian and alligator SP-A2 proteins all lacked the collagen domain completely. Both avian SP-A1 and SP-A2 sequences form separate clades, which are most closely related to their closest relatives, the alligators. The C-terminal carbohydrate recognition domain (CRD) of zebra finch SP-A1 was structurally almost identical to that of rat SP-A. In fact, the CRD of SP-A is highly conserved among all the vertebrates. Birds retained a truncated version of mammalian type SP-A1 as well as a non-collagenous C-type lectin, designated SP-A2, while losing the large collagenous SP-D lectin, reflecting their evolutionary trajectory towards a unidirectional respiratory system. In the context of zoonotic infections, how these evolutionary changes affect avian pulmonary surface protection is not clear

Chimeric Peptidomimetic Antibiotic Efficiently Neutralizes Lipopolysaccharides (LPS) and Bacteria-Induced Activation of RAW Macrophages

Peptide antibiotics have gathered attention given the urgent need to discover antimicrobials with new mechanisms of action. Their extended role as immunomodulators makes them interesting candidates for the development of compounds with dual mode of action. The objective of this study was to test the anti-inflammatory capacity of a recently reported chimeric peptidomimetic antibiotic (CPA) composed of polymyxin B nonapeptide (PMBN) and a macrocyclic β-hairpin motif (MHM). We investigated the potential of CPA to inhibit lipopolysaccharide (LPS)-induced activation of RAW264.7 macrophages. In addition, we elucidated which structural motif was responsible for this activity by testing CPA, its building blocks, and their parent compounds separately. CPA showed excellent LPS neutralizing activity for both smooth and rough LPSs. At nanomolar concentrations, CPA completely inhibited LPS-induced nitric oxide, TNF-α, and IL-10 secretion. Murepavadin, MHM, and PMBN were incapable of neutralizing LPS in this assay, while PMB was less active compared to CPA. Isothermal titration calorimetry showed strong binding between the CPA and LPS with similar binding characteristics also found for the other compounds, indicating that binding does not necessarily correlate with neutralization of LPS. Finally, we showed that CPA-killed bacteria caused significantly less macrophage activation than bacteria killed with gentamicin, heat, or any of the other compounds. This indicates that the combined killing activity and LPS neutralization of CPA can prevent unwanted inflammation, which could be a major advantage over conventional antibiotics. Our data suggests that immunomodulatory activity can further strengthen the therapeutic potential of peptide antibiotics and should be included in the characterization of novel compounds

Human Cryptic Host Defence Peptide {GVF}27 Exhibits Anti-Infective Properties against Biofilm Forming Members of the Burkholderia cepacia Complex

Therapeutic solutions to counter Burkholderia cepacia complex (Bcc) bacteria are challenging due to their intrinsically high level of antibiotic resistance. Bcc organisms display a variety of potential virulence factors, have a distinct lipopolysaccharide naturally implicated in antimicrobial resistance. and are able to form biofilms, which may further protect them from both host defence peptides (HDPs) and antibiotics. Here, we report the promising anti-biofilm and immunomodulatory activities of human HDP GVF27 on two of the most clinically relevant Bcc members, Burkholderia multivorans and Burkholderia cenocepacia. The effects of synthetic and labelled GVF27 were tested on B. cenocepacia and B. multivorans biofilms, at three different stages of formation, by confocal laser scanning microscopy (CLSM). Assays on bacterial cultures and on human monocytes challenged with B. cenocepacia LPS were also performed. GVF27 exerts, at different stages of formation, antibiofilm effects towards both Bcc strains, a significant propensity to function in combination with ciprofloxacin, a relevant affinity for LPSs isolated from B. cenocepacia as well as a good propensity to mitigate the release of pro-inflammatory cytokines in human cells pre-treated with the same endotoxin. Overall, all these findings contribute to the elucidation of the main features that a good therapeutic agent directed against these extremely leathery biofilm-forming bacteria should possess

Mode of action of teixobactins in cellular membranes

The natural antibiotic teixobactin kills pathogenic bacteria without detectable resistance. The difficult synthesis and unfavourable solubility of teixobactin require modifications, yet insufficient knowledge on its binding mode impedes the hunt for superior analogues. Thus far, teixobactins are assumed to kill bacteria by binding to cognate cell wall precursors (Lipid II and III). Here we present the binding mode of teixobactins in cellular membranes using solid-state NMR, microscopy, and affinity assays. We solve the structure of the complex formed by an improved teixobactin-analogue and Lipid II and reveal how teixobactins recognize a broad spectrum of targets. Unexpectedly, we find that teixobactins only weakly bind to Lipid II in cellular membranes, implying the direct interaction with cell wall precursors is not the sole killing mechanism. Our data suggest an additional mechanism affords the excellent activity of teixobactins, which can block the cell wall biosynthesis by capturing precursors in massive clusters on membranes