The Presence of Peptidoglycan O-Acetyltransferase in Various Staphylococcal Species Correlates with Lysozyme Resistance and Pathogenicity

ABSTRACT Human-pathogenic bacteria that are able to cause persistent infections must have developed mechanisms to resist the immune defense system. Lysozyme, a cell wall-lytic enzyme, is one of the first defense compounds induced in serum and tissues after the onset of infection. Recently, we showed that Staphylococcus aureus is resistant to lysozyme by O acetylating its peptidoglycan (PG) by O-acetyltransferase (OatA). We asked the question of which staphylococcal species PG is O acetylated. We applied various methods, such as genome analysis, PCR, Southern blotting, lysozyme sensitivity assay, and verification of O acetylation of PG by high-performance liquid chromatography (HPLC) analysis. PCR analysis using S. aureus-derived oatA primers and Southern blotting did not yield reliable results with other staphylococcal species. Therefore, we used the HPLC-based assay to directly detect PG O acetylation. Our studies revealed that the muramic acid was O acetylated only in pathogenic, lysozyme-resistant staphylococci (e.g., S. aureus, S. epidermidis, S. lugdunensis, and others). All nonpathogenic species were lysozyme sensitive. They can be divided into sensitive species (e.g., S. carnosus, S. gallinarum, and S. xylosus) and hypersensitive species (e.g., S. equorum, S. lentus, and S. arlettae). In all lysozyme-sensitive species, the analyzed PG was de-O-acetylated. When we transformed the oatA gene from lysozyme-resistant S. aureus into S. carnosus, the corresponding transformants also became lysozyme resistant.

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AMPK activates Parkin independent autophagy and improves post sepsis immune defense against secondary bacterial lung infections

Scientific Reports ◽

10.1038/s41598-021-90573-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nathaniel B. Bone ◽

Eugene J. Becker ◽

Maroof Husain ◽

Shaoning Jiang ◽

Anna A. Zmijewska ◽

...

Keyword(s):

Bacterial Infections ◽

Pathogenic Bacteria ◽

Inflammatory Responses ◽

Abdominal Sepsis ◽

Immune Defense ◽

Bacterial Killing ◽

Lung Infections ◽

Sepsis Survivors ◽

The Impact

AbstractMetabolic and bioenergetic plasticity of immune cells is essential for optimal responses to bacterial infections. AMPK and Parkin ubiquitin ligase are known to regulate mitochondrial quality control mitophagy that prevents unwanted inflammatory responses. However, it is not known if this evolutionarily conserved mechanism has been coopted by the host immune defense to eradicate bacterial pathogens and influence post-sepsis immunosuppression. Parkin, AMPK levels, and the effects of AMPK activators were investigated in human leukocytes from sepsis survivors as well as wild type and Park2−/− murine macrophages. In vivo, the impact of AMPK and Parkin was determined in mice subjected to polymicrobial intra-abdominal sepsis and secondary lung bacterial infections. Mice were treated with metformin during established immunosuppression. We showed that bacteria and mitochondria share mechanisms of autophagic killing/clearance triggered by sentinel events that involve depolarization of mitochondria and recruitment of Parkin in macrophages. Parkin-deficient mice/macrophages fail to form phagolysosomes and kill bacteria. This impairment of host defense is seen in the context of sepsis-induced immunosuppression with decreased levels of Parkin. AMPK activators, including metformin, stimulate Parkin-independent autophagy and bacterial killing in leukocytes from post-shock patients and in lungs of sepsis-immunosuppressed mice. Our results support a dual role of Parkin and AMPK in the clearance of dysfunctional mitochondria and killing of pathogenic bacteria, and explain the immunosuppressive phenotype associated Parkin and AMPK deficiency. AMPK activation appeared to be a crucial therapeutic target for the macrophage immunosuppressive phenotype and to reduce severity of secondary bacterial lung infections and respiratory failure.

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Overproduction of Ristomycin A by Activation of a Silent Gene Cluster in Amycolatopsis japonicum MG417-CF17

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03512-14 ◽

2014 ◽

Vol 58 (10) ◽

pp. 6185-6196 ◽

Cited By ~ 51

Author(s):

Marius Spohn ◽

Norbert Kirchner ◽

Andreas Kulik ◽

Angelika Jochim ◽

Felix Wolf ◽

...

Keyword(s):

Mass Spectrometry ◽

Gene Cluster ◽

High Performance ◽

Pathogenic Bacteria ◽

Genome Mining ◽

Gene Clusters ◽

Von Willebrand Disease ◽

Biosynthesis Gene Cluster ◽

Content Type ◽

Bioinformatic Tools

ABSTRACTThe emergence of antibiotic-resistant pathogenic bacteria within the last decades is one reason for the urgent need for new antibacterial agents. A strategy to discover new anti-infective compounds is the evaluation of the genetic capacity of secondary metabolite producers and the activation of cryptic gene clusters (genome mining). One genus known for its potential to synthesize medically important products isAmycolatopsis. However,Amycolatopsis japonicumdoes not produce an antibiotic under standard laboratory conditions. In contrast to mostAmycolatopsisstrains,A. japonicumis genetically tractable with different methods. In order to activate a possible silent glycopeptide cluster, we introduced a gene encoding the transcriptional activator of balhimycin biosynthesis, thebbrgene fromAmycolatopsis balhimycina(bbrAba), intoA. japonicum. This resulted in the production of an antibiotically active compound. Following whole-genome sequencing ofA. japonicum, 29 cryptic gene clusters were identified by genome mining. One of these gene clusters is a putative glycopeptide biosynthesis gene cluster. Using bioinformatic tools, ristomycin (syn. ristocetin), a type III glycopeptide, which has antibacterial activity and which is used for the diagnosis of von Willebrand disease and Bernard-Soulier syndrome, was deduced as a possible product of the gene cluster. Chemical analyses by high-performance liquid chromatography and mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS), and nuclear magnetic resonance (NMR) spectroscopy confirmed thein silicoprediction that the recombinantA. japonicum/pRM4-bbrAbasynthesizes ristomycin A.

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Composition chimique de sèves xylémiques du genre Lycopersicon (Solanaceae) en relation avec l'environnement. I. Effet de la température

Canadian Journal of Botany ◽

10.1139/b90-255 ◽

1990 ◽

Vol 68 (9) ◽

pp. 1942-1947 ◽

Cited By ~ 5

Author(s):

Philippe Brunet ◽

Bruno Sarrobert ◽

Nicole Paris-Pireyre ◽

Ange-Marie Risterucci

Keyword(s):

Amino Acids ◽

Low Temperature ◽

High Performance ◽

Xylem Sap ◽

Lycopersicon Hirsutum ◽

Fresh Weight ◽

Sensitive Species ◽

Composition Chimique ◽

Analytical Processing ◽

Two Temperature

Two species of tomato, Lycopersicon esculentum Mill. var. EGE12P1 and Lycopersicon hirsutum Humb. & Bonpl. ecotype LA 1777, were submitted to two temperature treatments, 20 or 10 °C. After a short study of plant growth, we analysed the chemical composition (cations, anions, and amino acids) of xylem sap by high performance liquid chromatography. A comparison of fresh weight increase at 20 and 10 °C of both plant species showed that L. hirsutum was the least affected by low temperature. The volumes of secreted sap and the quantities of ions transported showed great disturbances in the sensitive species (L. esculentum), especially in the case of potassium. In xylem sap of both species studied, but only at 10 °C, we noticed the appearance of ammonium. The possibility of contamination during analytical processing was eliminated. Moreover, determinations of amino acids levels showed that ammonium did not arise from degradation of amides present in xylem sap. In any event, the proportion of nitrate absorbed and reduced in roots increased at low temperature; it is much more important in L. hirsutum and could constitute a tolerance factor to low temperatures. Key words: ammonium, low temperature, Lycopersicon, xylem sap.

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Touchable 3D hierarchically structured polyaniline nanoweb for capture and detection of pathogenic bacteria

Nano Convergence ◽

10.1186/s40580-021-00280-9 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Kyung Hoon Kim ◽

MinHo Yang ◽

Younseong Song ◽

Chi Hyun Kim ◽

Young Mee Jung ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Pathogenic Bacteria ◽

Bacterial Pathogens ◽

Physical Contact ◽

Structural Deformation ◽

Pcr Analysis ◽

Mechanical Resistance ◽

Fluorescence Signal ◽

The Real

AbstractA bacteria-capturing platform is a critical function of accurate, quantitative, and sensitive identification of bacterial pathogens for potential usage in the detection of foodborne diseases. Despite the development of various nanostructures and their surface chemical modification strategies, relative to the principal physical contact propagation of bacterial infections, mechanically robust and nanostructured platforms that are available to capture bacteria remain a significant problem. Here, a three-dimensional (3D) hierarchically structured polyaniline nanoweb film is developed for the efficient capture of bacterial pathogens by hand-touching. This unique nanostructure ensures sufficient mechanical resistance when exposed to compression and shear forces and facilitates the 3D interfacial interactions between bacterial extracellular organelles and polyaniline surfaces. The bacterial pathogens (Escherichia coli O157:H7, Salmonella enteritidis, and Staphylococcus aureus) are efficiently captured through finger-touching, as verified by the polymerase chain reaction (PCR) analysis. Moreover, the real-time PCR results of finger-touched cells on a 3D nanoweb film show a highly sensitive detection of bacteria, which is similar to those of the real-time PCR using cultured cells without the capturing step without any interfering of fluorescence signal and structural deformation during thermal cycling. Graphic Abstract

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Abstract 456: Myxoma Viral Proteins, M-T7, Serp-1 and Serp-2, Alter Human Monocyte Gene Expression in Vitro

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.32.suppl_1.a456 ◽

2012 ◽

Vol 32 (suppl_1) ◽

Author(s):

Jennifer Davids ◽

Mee Y Bartee ◽

Richard W Moyer ◽

Alexandra R Lucas

Keyword(s):

Gene Expression ◽

Animal Models ◽

Arterial Occlusion ◽

Viral Proteins ◽

Immune Defense ◽

Pcr Analysis ◽

Monocytic Cells ◽

Plaque Growth ◽

Anti Inflammatory ◽

Significant Expression

Introduction: Atherosclerosis is characterized by ongoing chronic inflammation, cell damage, apoptosis and scar formation all of which can initiate plaque growth and arterial occlusion. These proteases are controlled by serine protease inhibitors, or serpins, which regulate apoptotic and inflammatory pathways. Complex DNA viruses, such as myxomavirus, have developed highly active immune defense systems which include viral serpins that inhibit inflammation at picogram to microgram doses. Serp-1, a secreted serpin, significantly reduces inflammatory cell activation, invasion and plaque growth in animal models and is in clinical trials. One cross-class serpin, Serp-2, has demonstrated anti-inflammatory and anti-apoptotic effects in a variety of animal models. M-T7, a secreted non-serpin chemokine binding protein, reduces vascular plaque and inflammation. Previous microarray experiments detected no significant changes with viral protein treatment alone, underscoring a need for activated cells. This study assesses the effects of viral proteins with anti-inflammatory and anti-atherogenic activity on atherosclerosis-related gene expression changes in activated human monocytes. Methods: Triplicate samples of THP-1 human monocytic cells were incubated with saline, 10μM camptothecin alone or in combination with individual serpins (500ng/million cells) for 30 mins at 37°C. Real-time RT-PCR analysis was performed. Results: At 30m, the viral proteins elicited significant expression changes in THP-1 monocytes for genes in purported atherosclerotic pathways. CCL2 was upregulated by Serp-1 (P = 0.0031). PDGFB was significantly increased by Serp-1 (P = 0.0203) and to a lesser extent by Serp-2 and M-T7. M-T7 significantly upregulated L-Selectin (P = 0.0023). Serp-2 significantly downregulated Lipoprotein(a) (P =0.0500). Conclusion: Significant expression changes were detected in human monocytic cells after treatment with three unique anti-inflammatory viral proteins. Differential regulation of genes such as PDGFB underscores the multifaceted approach viral proteins take toward controlling inflammation. Altering atherogenic responses in monocytic cells represents a new potential therapeutic target for inflammatory vascular diseases.

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Keratinocyte Expression of Human β Defensin 2 following Bacterial Infection: Role in Cutaneous Host Defense

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.10.1.161-166.2003 ◽

2003 ◽

Vol 10 (1) ◽

pp. 161-166 ◽

Cited By ~ 50

Author(s):

James G. H. Dinulos ◽

Laurel Mentele ◽

L. Page Fredericks ◽

Beverly A. Dale ◽

Gary L. Darmstadt

Keyword(s):

Host Defense ◽

Staphylococcus Epidermidis ◽

Pathogenic Bacteria ◽

Skin Surface ◽

Immune Defense ◽

Skin Infections ◽

Reverse Transcription Pcr ◽

Relative Tolerance ◽

Disease Induction ◽

Stimulation Of

ABSTRACT Human β defensin 2 (hβD-2) is thought to play an important role in cutaneous immune defense. We hypothesized that (i) keratinocyte expression of hβD-2, measured by reverse transcription-PCR, would be upregulated in response to challenge with pathogenic bacteria, particularly highly adherent strains of Streptococcus pyogenes and Staphylococcus aureus, and (ii) hβD-2 would have potent antimicrobial activity against pathogenic but not commensal organisms. Expression of hβD-2 was induced consistently by S. aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa, whereas strains of S. pyogenes were poor and variable inducers of hβD-2. No correlation was found between levels of bacterial adherence and keratinocyte expression of hβD-2. S. pyogenes was significantly more sensitive to killing by hβD-2 than S. epidermidis. We conclude that the ability to induce hβD-2 expression in combination with sensitivity to its antimicrobial effects may contribute to the rarity of skin infections with the gram-negative bacterial organisms, whereas lack of stimulation of hβD-2 expression by S. pyogenes may be important in its ability to evade innate defenses and cause skin disease. Induction of expression of hβD-2 but relative tolerance to it may enable S. epidermidis to survive on the skin surface and modulate hβD-2 expression when the stratum corneum barrier is disrupted.

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Human Cytomegalovirus Transmission from the Uterus tothe Placenta Correlates with the Presence of Pathogenic Bacteria andMaternalImmunity

Journal of Virology ◽

10.1128/jvi.77.24.13301-13314.2003 ◽

2003 ◽

Vol 77 (24) ◽

pp. 13301-13314 ◽

Cited By ~ 85

Author(s):

Lenore Pereira ◽

Ekaterina Maidji ◽

Susan McDonagh ◽

Olga Genbacev ◽

Susan Fisher

Keyword(s):

Dna Sequences ◽

Intrauterine Growth Restriction ◽

Cytomegalovirus Infection ◽

Pathogenic Bacteria ◽

Pcr Analysis ◽

Herpes Simplex Viruses ◽

Intrauterine Growth ◽

Biopsy Specimens ◽

Decidual Cells ◽

Maternal Fetal Interface

ABSTRACT Prenatal cytomegalovirus infection may cause pregnancy complications such as intrauterine growth restriction and birth defects. How virus from the mother traverses the placenta is unknown. PCR analysis of biopsy specimens of the maternal-fetal interface revealed that DNA sequences from cytomegalovirus were commonly found with those of herpes simplex viruses and pathogenic bacteria. Cytomegalovirus DNA and infected cell proteins were found more often in the decidua than in the placenta, suggesting that the uterus functions as a reservoir for infection. In women with low neutralizing titers, cytomegalovirus replicated in diverse decidual cells and placental trophoblasts and capillaries. In women with intermediate to high neutralizing titers, decidual infection was suppressed and the placenta was spared. Overall, cytomegalovirus virions and maternal immunoglobulin G were detected in syncytiotrophoblasts, villus core macrophages, and dendritic cells. These results suggest that the outcome of cytomegalovirus infection depends on the presence of other pathogens and coordinated immune responses to viral replication at the maternal-fetal interface.

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Characteristic of Hybrid Cellulose-Amino Functionalized POSS-Silica Nanocomposite and Antimicrobial Activity

Journal of Nanomaterials ◽

10.1155/2015/936590 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 7

Author(s):

Sivalingam Ramesh ◽

Jaehwan Kim ◽

Joo-Hyung Kim

Keyword(s):

Coupling Agent ◽

High Performance ◽

Pathogenic Bacteria ◽

Sol Gel ◽

Hybrid Nanocomposites ◽

Morphological Properties ◽

Regenerated Cellulose ◽

Polyhedral Oligomeric Silsesquioxanes ◽

Covalent Crosslinking ◽

Silica Hybrid

Recently, cellulose has much attention as an emerging renewable nanomaterial which holds promising properties having unique piezoelectricity, insulating, and biodegradable nature for various applications. Also, the modified properties of cellulose by appropriate chemical modifications in various functional groups with outstanding properties or significantly improved physical, chemical, biological, and electronic properties will widen the way for it to be utilized in different usages. Therefore, in this paper, cellulose-functionalized polyhedral oligomeric silsesquioxanes (POSS) based materials were considered an important class of high-performance hybrid nanocomposite materials. To functionalize the regenerated cellulose, amino functionalized POSS material was synthesized via sol-gel covalent crosslinking process in presence of amino coupling agent. In this reaction, tetraethoxsilane (TEOS) andγ-aminopropyltriethoxy silane (γ-APTES) as coupling agent for metal precursors were selected. The chemical structure of cellulose-amine functionalized bonding and covalent crosslinking hybrids was confirmed by FTIR and1H NMR spectral analysis. From the TEM results, well-dispersed hybrid cellulose-functionalized POSS-silica composites are observed. The resulting cellulose-POSS-silica hybrid nanocomposites materials provided significantly improved the optical transparency, and thermal and morphological properties to compare the cellulose-silica hybrid materials. Further, antimicrobial test against pathogenic bacteria was carried out.

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Comparison of an oligo-chip based assay with PCR method to measure the prevalence of tick-borne pathogenic bacteria in central Slovakia

Biologia ◽

10.2478/s11756-008-0007-1 ◽

2008 ◽

Vol 63 (1) ◽

Cited By ~ 1

Author(s):

Elena Kocianová ◽

Dušan Blaškovič ◽

Katarína Smetanová ◽

Katarína Schwarzová ◽

Vojtech Boldiš ◽

...

Keyword(s):

Francisella Tularensis ◽

Coxiella Burnetii ◽

Pathogenic Bacteria ◽

Spotted Fever ◽

Close Correlation ◽

Borrelia Burgdorferi Sensu Lato ◽

Pcr Analysis ◽

Spotted Fever Group ◽

Specific Pcr ◽

Wide Range

AbstractTicks are well-known vectors for a wide range of pathogenic microorganisms. We examined the presence of Rickettsia spp., Anaplasma spp., Borrelia spp., Coxiella burnetii and Francisella tularensis in Ixodes ricinus ticks collected in central Slovakia using oligo-chip based assay. Rickettsiae were detected in 5.6% of examined ticks. Borreliae and anaplasmae were identified in 2.1% and 2.8% ticks, respectively. All tested samples were negative for presence of Coxiella burnetii and Francisella tularensis. All these results were compared with those obtained by PCR analysis, and a close correlation between them was found. In addition, rickettsiae of spotted fever group (SFG), Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato were found in ticks using genera or species-specific PCR methods. They are circulating in 10 out of 18 studied localities.

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Toward Understanding the Function of Amelogenin Using Transgenic Mice

Advances in Dental Research ◽

10.1177/08959374960100021501 ◽

1996 ◽

Vol 10 (2) ◽

pp. 208-214 ◽

Cited By ~ 1

Author(s):

K. Ibaraki-O'Connor ◽

K. Nakata ◽

M.F. Young

Keyword(s):

Southern Blotting ◽

Signal Sequence ◽

Transgenic Animals ◽

Full Length ◽

Pcr Analysis ◽

Coding Region ◽

Chain Reaction ◽

Mammalian Expression ◽

Ectopic Production ◽

Polymerase Chain

The purpose of this study was to establish transgenic mouse lines as a tool to investigate the function of amelogenin during mineralization by causing ectopic production of amelogenin and studying its effect. The mouse amelogenin (mAme) was cloned from a 16-day-old whole mouse embryo cDNA library and was determined to be "full-length" mouse amelogenin (with a complete coding region) by comparison with the mouse amelogenin reported previously by Snead et al. (1985) and Lau et al. (1992). The overexpression construct contained: (1) the rat osteocalcin (OC) promoter (1.8 kb); (2) the adenovirus splicing casettes, including introgenic (Int) sequence (0.3 kb); (3) the full-length mAme cDNA (0.8 kb); and (4) the polyadenylation signal sequence from the pSG5 mammalian expression vector. Both Southern blotting and polymerase chain-reaction (PCR) analyses were performed, by means of a specific probe and a pair of oligodeoxynucleotides to OclntmAme(A)+, respectively. The animals which showed transgene-positive in both analyses were further used to establish F1 animals. Heterozygocity was confirmed with F1 animals by PCR analysis of DNA from the F0 x FVB/N pups. Three independent transgenic F1 heterozygous lines (640t, 706t, and 708t) have now been established. The generation of F2 homozygous lines is under way. The heterozygous transgenic animals are currently being analyzed for alterations in the morphology and structure of various bone tissues.

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