ABSTRACT: An alkaliphilic isosaccharinic acid polymicrobial floc forming community operating under intermediate level waste conditions at pH 11. Targeted loci cultured
Project description:To describe the transcriptional changes associated with polymicrobial-sepsis induced myocardial depression in wild type and iNOS deficient mice. Keywords: myocardium, contractility, differential gene expression, nitric oxide synthase, infection We compared the transcriptional profile of C57/BL6 WT mice and congenic B6 129P2-Nos2tm1Lau/J mice after 48 hrs of polymicrobial sepsis induced by caecal ligation and perforation. 48 hours after surgery, mice were anaesthetised (intraperitoneal 100 mg/kg ketamine and 10 mg/kg xylazine). The right common carotid artery was cannulated (Millar Mikro-Tip pressure transducing catheter: 1.4F sensor, 2F catheter; Houston TX). Pressure tracings from the aorta and left ventricle were recorded (SonoLAB software; Sonometrics Corp., London Ontario Canada) and analysed using Cardiosoft and Origin 6.0 (Sonometrics Corp., and Microcal Software, Northampton MA). The heart was removed, emptied of blood, and snap frozen.
Project description:Many human infections are polymicrobial in origin, and interactions among community inhabitants shape colonization patterns and pathogenic potential1. However, few interspecies interactions have been functionally dissected at the molecular level or characterized on a systems level. Periodontitis, which is the sixth most prevalent infectious disease worldwide2, ensues from the action of dysbiotic polymicrobial communities3. The keystone pathogen Porphyromonas gingivalis and the accessory pathogen Streptococcus gordonii interact to form communities in vitro and exhibit increased fitness in vivo3, 4. The mechanistic basis of this polymicrobial synergy, however, has not been fully elucidated. Here we show that streptococcal 4 aminobenzoate/para-amino benzoic acid (pABA) is required for maximal accumulation of P. gingivalis in dual species communities. Metabolomic and proteomic data showed that exogenous pABA is utilized for folate biosynthesis, and leads to decreased stress and elevated expression of fimbrial interspecies adhesins. Moreover, pABA increased the colonization and survival of P. gingivalis in a murine oral infection model. However, pABA also caused a reduction in virulence in vivo and suppressed extracellular polysaccharide production by P. gingivalis. Collectively, these data reveal a multidimensional aspect to P. gingivalis-S. gordonii interactions and establish pABA as a critical cue produced by a partner species that enhances fitness of P. gingivalis while diminishing virulence.
Project description:We systematically assessed the transcriptomic changes of livers of MxCreFthD/D vs. Fthlox/lox mice after induction of polymicrobial sepsis using Cecal Ligation and Puncture. Data indicates a distinct set of genes differentially regulated between MxCreFthD/D and Fthlox/lox mice after sepsis induction reflecting altered iron and glucose metabolism.
Project description:The interaction of clinically relevant microorganisms is the focus of various studies, e.g. the interaction between the pathogenic yeast, Candida albicans, and the bacterium, Pseudomonas aeruginosa and these interactions can alter the outcome of infection, growth dynamics of each species and antimicrobial resistance of pathogens. During infection, both C. albicans and P. aeruginosa can elicit the release arachidonic acid (AA) from host cells membranes through the action of phospholipases. This polyunsaturated fatty acid can be transformed into immune-modulating compounds, termed eicosanoids, by both host-derived and microbial-derived enzymatic reactions. In its free form, AA can affect the growth of both C. albicans and P. aeruginosa, inhibiting the morphogenesis of C. albicans as well as reducing resistance towards antifungal agents. However, the mechanism of this is unknown. Previous studies on the effect of polyunsaturated fatty acids have indicated a possible alteration in plasma membrane organisation and permeability. Our group aimed to address how AA affects C. albicans in both single species biofilms, as well as in polymicrobial biofilms with P. aeruginosa. RNAseq was performed on single and polymicrobial biofilms in the presence and absence of a sub-inhibitory (100 µM) concentration of AA. Differential expression was determined between C. albicans single species biofilms in the presence and absence of AA. Secondly, the influence of co-incubation of C. albicans with P. aeruginosa in the absence of AA was evaluated to identify novel facets of interaction not previously identified, and to establish a baseline to determine the effect of AA on C. albicans in polymicrobial biofilms. Lastly, the effect of AA on C. albicans in polymicrobial biofilms was determined through comparison with polymicrobial biofilms in the absence of AA. This study provides a comprehensive analysis of the effect of AA and both co-incubation of C. albicans with P. aeruginosa focused on the transcriptome.
Project description:The objectives of this investigation were to examine changes in the host transcriptional profiles during a polymicrobial periodontal pathogens Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia infection using a murine calvarial model of inflammation and bone resorption. P. gingivalis FDC 381, T. denticola ATCC 35404, and T. forsythia ATCC 43037 was injected into the subcutaneous soft tissue over the calvaria of BALB/c mice for 3 days, after which the soft tissues and calvarial bones were excised. RNA was isolated from infected soft tissues and calvarial bones and analyzed for transcript profiles using Murine GeneChipM-BM-. MG-MOE430A Affymetrix arrays to provide a molecular profile of the events that occur following infection of these tissues. We used mouse microarrays to detail the molecular profile of the events that occur following infection of calvarial and bone tissues and identified distinct classes of up- and down-regulated genes during this process. P. gingivalis/T. denticola/T. forsythia was injected at 5 x 108 each (N = 10) into the soft tissues overlying the calvaria of the mice for 3 days. A control group (N = 9) was injected with vehicle once daily for 3 days. Mice were euthanized 8 h after the last injection. The calvarial bones and overlying soft tissues from 5 mice in each group were excised, snap frozen in liquid nitrogen, and stored at M-bM-^@M-^S80M-BM-0C until RNA isolation. Total RNA was isolated from the frozen calvarial tissue and calvarial bone from each mouse (Polymicrobial bacteria infected and control animals, N = 5 in each group) with Trizol reagent (Invitrogen, CA). Equal amounts of RNA from samples were labeled and hybridized on a mouse GeneChip following the protocol described in the GeneChip Expression Analysis Technical manual (Affymetrix, Santa Clara, CA). After hybridization, the GeneChip arrays were stained and scanned in an Affymetrix GCS 3000 7G Scanner.
Project description:Innate immunity is fundamental to recognition and clearance of bacterial infection. The relevant cells and molecules that orchestrate an effective response, however, remain incompletely understood. Here we describe a previously unknown population of B cells, which we have named innate response activator (IRA) B cells that recognize bacteria directly through TLR-4-MyD88 and protect against polymicrobial sepsis. IRA-B cells have a unique IgM high CD23 low CD43 + CD93+ GM-CSF+ signature, develop and diverge from B1a B cells, require BAFFR, and adhere to tissue via VLA-4 and LFA-1. B cell subsets are sorted from the spleen and peritoneum of C57BL/6 mice that were given intraperitoneal injections of LPS once daily for four days.
Project description:Staphylococcus aureus (Sa) and Acinetobacter baumannii (Ab) are frequently co-isolated from polymicrobial infections that are severe and recalcitrant to therapy. Here, we apply a combination of wet-lab experiments and in silico modeling to unveil the intricate nature of the Ab/Sa interaction using both, representative laboratory strains and strains co-isolated from clinical samples. This comprehensive methodology allowed uncovering Sa's capability to exert a partial interference on Ab by the expression of phenol-soluble modulins. Additionally, we observed a cross-feeding mechanism, wherein Sa supports Ab's growth by providing acetoin as an alternative carbon source. This study marks the pioneering work to dissect Ab/Sa interaction dynamics wherein competitive and cooperative dynamics can intertwine. Through our findings, we illuminate the ecological mechanisms underpinning their coexistence in the context of polymicrobial infections. Our research not only enriches our understanding but also opens doors to potential therapeutic avenues in managing these challenging infections.