Hydrophobic lung surfactant proteins B and C remain associated with surface film during dynamic cyclic area changes

AbstractThe biophysical activity of lung surfactant depends, to a large extent, on the presence of the hydrophobic surfactant proteins B (SP-B) and C (SP-C). The role of these proteins in lipid adsorption and lipid squeeze-out under dynamic conditions simulating breathing is not yet clear. Therefore, the aim of this study was to investigate the interaction of spread hydrophobic surfactant proteins with phospholipids in a captive-bubble surfactometer during rapid cyclic area changes (6 cycles/min). We found that SP-B and SP-C facilitated the rapid transport of lipids into the air–water interface in a concentration-dependent manner (threshold concentration ≥0.05:0.5 mol% SP-B/SP-C). Successive rapid cyclic area changes did not affect the concentration-dependent lipid adsorption process, suggesting that SP-B and SP-C remained associated with the surface film

Antimicrobial host defence peptides: functions and clinical potential

Cationic host defence peptides (CHDP), also known as antimicrobial peptides, are naturally occurring peptides that can combat infections through their direct microbicidal properties and/or by influencing the host's immune responses. The unique ability of CHDP to control infections as well as resolve harmful inflammation has generated interest in harnessing the properties of these peptides to develop new therapies for infectious diseases, chronic inflammatory disorders and wound healing. Various strategies have been used to design synthetic optimized peptides, with negligible toxicity. Here, we focus on the progress made in understanding the scope of functions of CHDP and the emerging potential clinical applications of CHDP-based therapies

Physiological consequences of inactivation of lgmB and lpxL1, two genes involved in lipid A synthesis in Bordetella bronchiseptica

To develop a Bordetella bronchiseptica vaccine with reduced endotoxicity, we previously inactivated lpxL1, the gene encoding the enzyme that incorporates a secondary 2-hydroxy-laurate in lipid A. The mutant showed a myriad of phenotypes. Structural analysis showed the expected loss of the acyl chain but also of glucosamine (GlcN) substituents, which decorate the phosphates in lipid A. To determine which structural change causes the various phenotypes, we inactivated here lgmB, which encodes the GlcN transferase, and lpxL1 in an isogenic background and compared the phenotypes. Like the lpxL1 mutation, the lgmB mutation resulted in reduced potency to activate human TLR4 and to infect macrophages and in increased susceptibility to polymyxin B. These phenotypes are therefore related to the loss of GlcN decorations. The lpxL1 mutation had a stronger effect on hTLR4 activation and additionally resulted in reduced murine TLR4 activation, surface hydrophobicity, and biofilm formation, and in a fortified outer membrane as evidenced by increased resistance to several antimicrobials. These phenotypes, therefore, appear to be related to the loss of the acyl chain. Moreover, we determined the virulence of the mutants in the Galleria mellonella infection model and observed reduced virulence of the lpxL1 mutant but not of the lgmB mutant

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

Validation of reference genes for quantitative RT-PCR studies in porcine oocytes and preimplantation embryos

<p>Abstract</p> <p>Background</p> <p>In the developing embryo, total RNA abundance fluctuates caused by functional RNA degradation and zygotic genome activation. These variations in the transcriptome in early development complicate the choice of good reference genes for gene expression studies by quantitative real time polymerase chain reaction.</p> <p>Results</p> <p>In order to identify stably expressed genes for normalisation of quantitative data, within early stages of development, transcription levels were examined of 7 frequently used reference genes (<it>B2M, BACT, GAPDH, H2A, PGK1, SI8</it>, and <it>UBC</it>) at different stages of early porcine embryonic development (germinal vesicle, metaphase-2, 2-cell, 4-cell, early blastocyst, expanded blastocyst). Analysis of transcription profiling by geNorm software revealed that <it>GAPDH, PGK1, S18</it>, and <it>UBC </it>showed high stability in early porcine embryonic development, while transcription levels of <it>B2M, BACT</it>, and <it>H2A </it>were highly regulated.</p> <p>Conclusion</p> <p>Good reference genes that reflect total RNA content were identified in early embryonic development from oocyte to blastocyst. A selection of either <it>GAPDH </it>or <it>PGK1</it>, together with ribosomal protein <it>S18 </it>(<it>S18</it>), and <it>UBC </it>is proposed as reference genes, but the use of <it>B2M, BACT</it>, or <it>H2A </it>is discouraged.</p

Evolutionary diversification of defensins and cathelicidins in birds and primates

Divergent evolution for more than 310 million years has resulted in an avian immune system that is complex and more compact than that of primates, sharing much of its structure and functions. Not surprisingly, well conserved ancient host defense molecules, such as defensins and cathelicidins, have diversified over time. In this review, we describe how evolution influenced the host defense peptides repertoire, its distribution, and the relationship between structure and biological functions. Marked features of primate and avian HDPs are linked to species-specific characteristics, biological requirements, and environmental challenge

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

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

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