Query: lysozyme

title: Fecal bacteria and metabolite responses to dietary lysozyme in a sow model from late gestation until lactation
abstract: Lysozyme (LZM) is a natural anti bacterial protein that is found in the saliva, tears and milk of all mammals including humans. Its anti bacterial properties result from the ability to cleave bacterial cell walls, causing bacterial death. The current study was conducted to investigate the effects of dietary LZM on fecal microbial composition and variation in metabolites in sow. The addition of LZM decreased the fecal short chain fatty acids (SCFAs) Zonulin and endotoxin in the serum, and feces, were decreased with lysozyme supplementation. Furthermore, fecal concentrations of lipocalin 2 and the pro inflammatory cytokine TNF a were also decreased while the anti inflammatory cytokine IL 10 was increased by lysozyme supplementation. 16S rRNA gene sequencing of the V3 V4 region suggested that fecal microbial levels changed at different taxonomic levels with the addition of LZM. Representative changes included the reduction of diversity between sows, decreased Bacteroidetes Actinobacteria Tenericutes and Spirochaetes during lactation as well as an increase in Lactobacillus These findings suggest that dietary lysozyme supplementation from late gestation to lactation promote microbial changes, which would potentially be the mechanisms by which maternal metabolites and inflammatory status was altered after LZM supplementation.

title: Broad Spectrum, Patient Adaptable Inhaled Niclosamide Lysozyme Particles are Efficacious Against Coronaviruses in Lethal Murine Infection Models
abstract: Niclosamide (NIC) has demonstrated promising in vitro antiviral efficacy against SARS CoV 2, the causative agent of the COVID 19 pandemic. Though NIC is already FDA approved, the oral formulation produces systemic drug levels that are too low to inhibit SARS CoV 2. As an alternative, direct delivery of NIC to the respiratory tract as an aerosol could target the primary site of for SARS CoV 2 acquisition and spread. We have developed a niclosamide powder suitable for delivery via dry powder inhaler, nebulizer, and nasal spray through the incorporation of human lysozyme (hLYS) as a carrier molecule. This novel formulation exhibits potent in vitro and in vivo activity against MERS CoV and SARS CoV 2 and may protect against methicillin resistance staphylococcus aureus pneumonia and inflammatory lung damage occurring secondary to CoV infections. The suitability of the formulation for all stages of the disease and low cost development approach will ensure wide spread utilization

title: Improved, two stage protein expression and purification via autoinduction of both autolysis and auto DNA/RNA hydrolysis conferred by phage lysozyme and DNA/RNA endonuclease
abstract: We report improved release of recombinant proteins in E. coli, which relies on combined cellular autolysis and DNA/RNA autohydrolysis, conferred by the tightly controlled autoinduction of both phage lysozyme and the non specific DNA/RNA endonuclease from S. marcescens. Autoinduction occurs in a two stage process wherein heterologous protein expression and autolysis enzymes are induced upon entry into stationary phase by phosphate depletion. Cytoplasmic lysozyme and periplasmic endonuclease are kept from inducing lysis until membrane integrity is disrupted. Post cell harvest, the addition of detergent (0.1% Triton X100) and a single 30 minutes freezer thaw cycle results in 90% release of protein (GFP) This cellular lysis is accompanied by complete oligonucleotide hydrolysis. The approach has been validated for shake flask cultures, high throughput cultivation in microtiter plates and larger scale stirred tank bioreactors. This tightly controlled system enables robust growth and resistance to lysis in routine media when cells are propagated and autolysis/hydrolysis genes are only induced upon phosphate depletion. Highlights Autoinduction of both cell lysis and nucleotide hydrolysis >90 lysis and DNA degradation Strains are stable to lysis in the absence of phosphate depletion.

title: Discovering loop conformational flexibility in T4 lysozyme mutants through artificial intelligence aided molecular dynamics
abstract: Proteins sample a variety of conformations distinct from their crystal structure. These structures, their propensities, and pathways for moving between them contain enormous information about protein function that is hidden from a purely structural perspective. Molecular dynamics simulations can uncover these higher energy states but often at a prohibitively high computational cost. Here we apply our recent statistical mechanics and artificial intelligence based molecular dynamics framework for enhanced sampling of protein loops in three mutants of the protein T4 lysozyme. We are able to correctly rank these according to the stability of their excited state. By analyzing reaction coordinates, we also obtain crucial insight into why these specific perturbations in sequence space lead to tremendous variations in conformational flexibility. Our framework thus allows accurate comparison of loop conformation populations with minimal prior human bias, and should be directly applicable to a range of macromolecules in biology, chemistry and beyond.

title: Ligand protein interactions in lysozyme investigated through a dual resolution model
abstract: A fully atomistic (AT) modeling of biological macromolecules at relevant length and time scales is often cumbersome or not even desirable, both in terms of computational effort required and a posteriori analysis. This difficulty can be overcome with the use of multiresolution models, in which different regions of the same system are concurrently described at different levels of detail. In enzymes, computationally expensive AT detail is crucial in the modeling of the active site in order to capture, for example, the chemically subtle process of ligand binding. In contrast, important yet more collective properties of the remainder of the protein can be reproduced with a coarser description. In the present work, we demonstrate the effectiveness of this approach through the calculation of the binding free energy of hen egg white lysozyme with the inhibitor di N acetylchitotriose. Particular attention is payed to the impact of the mapping, that is, the selection of AT and coarse grained residues, on the binding free energy. It is shown that, in spite of small variations of the binding free energy with respect to the active site resolution, the separate contributions coming from different energetic terms (such as electrostatic and van der Waals interactions) manifest a stronger dependence on the mapping, thus pointing to the existence of an optimal level of intermediate resolution.

title: Tissue Specificity in Social Context Dependent lysozyme Expression in Bumblebees
abstract: Group living at high densities may result in the enhanced transmission of pathogens. Social insects are obligate group living species, which often also exhibit high relatedness and frequent social interactions amongst individuals, resulting in a high risk of disease spread. Social species seem to exhibit immune systems that provide colonies of social insects with a certain level of flexibility for adjustment of immune activity according to the risk of disease spread. In bumblebees, Bombus terrestris, it was demonstrated that in group kept individuals, immune component activity and immune gene expression is increased, potentially as a prophylactic adaptation. Here, I tested whether social environment influences the gene expression pattern of two lysozyme genes, which are components of the antimicrobial response of the bumblebee. In addition, I tested gene expression activation in different tissues (gut, fat body) The analysis revealed that the gene, the density of individuals, the tissue, and the interaction of the latter are the main factors that influence the expression of lysozyme genes. This is the first report of a tissue specific response towards the social environment. This has implications for gene regulation, which must be responsive to social context dependent information.

title: Fish lysozyme gene family evolution and divergent function in early development.
abstract: Lysozymes are an ancient group of antimicrobial enzymes of the innate immune system. Here we provide a comparative analysis of the evolution and function of lysozymes during early development in fish, the most speciose vertebrate group. In fishes, lineage and species specific evolution of both C type (chicken or conventional) and G type (goose type) genes occurred. Phylogenetic analysis revealed that the teleost lysozyme G type members group with the tetrapod homologues but the teleost C type form three different clusters with the tetrapods. Most of the teleost C type cluster with tetrapod Lyz but there are some that group with the mammalian Lyzl1/2 and LALBA. This suggests that early in gnathostome evolution these genes already existed and that lyzl1/2 and lalba genes are present in fish and tetrapods. Gene synteny analysis to confirm sequence orthologies failed to identify conserved genome regions between teleosts and other vertebrates lysozyme gene regions suggesting that in the ancestral bony fish genome lyz, lyzl1/2, lalba and lyg precursor genes were transposed to different chromosome regions. The homologue of the mammalian lactalbumin (LALBA) gene was identified for the first time in teleosts and was expressed in skin and during egg and larval development. Lysozyme activity was detected in teleost eggs and varied between species and in the gilthead sea bream lyg and lalba transcript abundance differed in eggs and larvae from different brood stock suggesting differences exist in maternal innate immune protection.

title: Intestinal lysozyme liberates Nod1 ligands from microbes to direct insulin trafficking in pancreatic beta cells
abstract: Long range communication between intestinal symbiotic bacteria and extra intestinal organs can occur through circulating bacterial signal molecules, through neural circuits, or through cytokines or hormones from host cells. Here we report that Nod1 ligands derived from intestinal bacteria act as signal molecules and directly modulate insulin trafficking in pancreatic beta cells. The cytosolic peptidoglycan receptor Nod1 and its downstream adapter Rip2 are required for insulin trafficking in beta cells in a cell autonomous manner. Mechanistically, upon recognizing cognate ligands, Nod1 and Rip2 localize to insulin vesicles, recruiting Rab1a to direct insulin trafficking through the cytoplasm. Importantly, intestinal lysozyme liberates Nod1 ligands into the circulation, thus enabling long range communication between intestinal microbes and islets. The intestine islet crosstalk bridged by Nod1 ligands modulates host glucose tolerance. Our study defines a new type of inter organ communication based on circulating bacterial signal molecules, which has broad implications for understanding the mutualistic relationship between microbes and host.

title: Lipopolysaccharide Deficient Acinetobacter baumannii Due to Colistin Resistance Is Killed by Neutrophil Produced Lysozyme
abstract: Acinetobacter baumannii causes nosocomial infections due to its multidrug resistance and high environmental adaptability. Colistin is a polypeptide antibacterial agent that targets lipopolysaccharide (LPS) and is currently used to control serious multidrug resistant Gram negative bacterial infections, including those caused by A. baumannii. However, A. baumannii may acquire colistin resistance by losing their LPS. In mouse models, LPS deficient A. baumannii have attenuated virulence. Nevertheless, the mechanism through which the pathogen is cleared by host immune cells is unknown. Here, we established colistin resistant A. baumannii strains and analyzed possible mechanisms through which they are cleared by neutrophils. Colistin resistant, LPS deficient strains harbor mutations or insertion sequence (IS) in lpx genes, and introduction of intact lpx genes restored LPS deficiency. Analysis of interactions between these strains and neutrophils revealed that compared with wild type, LPS deficient A. baumannii only weakly stimulated neutrophils, with consequent reduced levels of reactive oxygen species (ROS) and inflammatory cytokine production. Nonetheless, neutrophils preferentially killed LPS deficient A. baumannii compared to wild type strains. Moreover, LPS deficient A. baumannii strains presented with increased sensitivities to antibacterial lysozyme and lactoferrin. We revealed that neutrophil secreted lysozyme was the antimicrobial factor during clearance of LPS deficient A. baumannii strains. These findings may inform the development of targeted therapeutics aimed to treat multidrug resistant infections in immunocompromised patients who are unable to mount an appropriate cell mediated immune response.

title: Novel Single Nucleotide Polymorphisms of Lysozyme (C Type) Gene in Donkey (Equus Asinus) Populations in Marmara Province of Turkey
abstract: The major antimicrobial proteins in donkey milk are lysozyme, lactoferrin, lactoperoxidase and immunoglobulins. Lysozyme has an important role in the host defense by way it inhibits the pathogenic bacteria. The aim of this study is to investigate the Lysozyme (LYZ) gene polymorphism in 82 donkeys reared in Thrace region of Turkey. 716 bp long partial 5' UTR, exon 1, intron 1, exon 2 regions of LYZ gene were amplified and PCR products were analyzed via DNA sequencing. Three novel single nucleotide polymorphisms (SNPs) were identified as g.1782775A>G, g.1782924A>G and g.1782960T>C in the first intron of LYZ gene. The partial DNA sequence of LYZ gene in donkeys was reported in the present study and sequences of LYZ were entered to NCBI Genbank database with the accession number: MK984689 MK984692. This SNP may have an effect on immune system and milk traits in donkeys and additional studies are needed to confirm this assumption for donkey breeding.