scholarly journals Bacteria autoaggregation: how and why bacteria stick together

2021 ◽  
Author(s):  
El-shama Q. A. Nwoko ◽  
Iruka N. Okeke
Keyword(s):  
Protein Interaction ◽  
Biofilm Formation ◽  
Ex Vivo ◽  
Therapeutic Targets ◽  
Phase Variation ◽  
Bacterial Adherence ◽  
Specific Interactions ◽  
Bacterial Cells ◽  
Qualitative And Quantitative

Autoaggregation, adherence between identical bacterial cells, is important for colonization, kin and kind recognition, and survival of bacteria. It is directly mediated by specific interactions between proteins or organelles on the surfaces of interacting cells or indirectly by the presence of secreted macromolecules such as eDNA and exopolysaccharides. Some autoaggregation effectors are self-associating and present interesting paradigms for protein interaction. Autoaggregation can be beneficial or deleterious at specific times and niches. It is, therefore, typically regulated through transcriptional or post-transcriptional mechanisms or epigenetically by phase variation. Autoaggregation can contribute to bacterial adherence, biofilm formation or other higher-level functions. However, autoaggregation is only required for these phenotypes in some bacteria. Thus, autoaggregation should be detected, studied and measured independently using both qualitative and quantitative in vitro and ex vivo methods. If better understood, autoaggregation holds the potential for the discovery of new therapeutic targets that could be cost-effectively exploited.

scholarly journals Quantifying fluorescent glycan uptake to elucidate strain-level variability in foraging behaviors of rumen bacteria

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Leeann Klassen ◽  
Greta Reintjes ◽  
Jeffrey P. Tingley ◽  
Darryl R. Jones ◽  
Jan-Hendrik Hehemann ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Ex Vivo ◽  
Rapid Assessment ◽  
Vital Role ◽  
Strain Level ◽  
Metabolic Phenotype ◽  
Specific Cell ◽  
Bacterial Cells ◽  
Carbohydrate Utilization

AbstractGut microbiomes, such as the microbial community that colonizes the rumen, have vast catabolic potential and play a vital role in host health and nutrition. By expanding our understanding of metabolic pathways in these ecosystems, we will garner foundational information for manipulating microbiome structure and function to influence host physiology. Currently, our knowledge of metabolic pathways relies heavily on inferences derived from metagenomics or culturing bacteria in vitro. However, novel approaches targeting specific cell physiologies can illuminate the functional potential encoded within microbial (meta)genomes to provide accurate assessments of metabolic abilities. Using fluorescently labeled polysaccharides, we visualized carbohydrate metabolism performed by single bacterial cells in a complex rumen sample, enabling a rapid assessment of their metabolic phenotype. Specifically, we identified bovine-adapted strains of Bacteroides thetaiotaomicron that metabolized yeast mannan in the rumen microbiome ex vivo and discerned the mechanistic differences between two distinct carbohydrate foraging behaviors, referred to as “medium grower” and “high grower.” Using comparative whole-genome sequencing, RNA-seq, and carbohydrate-active enzyme fingerprinting, we could elucidate the strain-level variability in carbohydrate utilization systems of the two foraging behaviors to help predict individual strategies of nutrient acquisition. Here, we present a multi-faceted study using complimentary next-generation physiology and “omics” approaches to characterize microbial adaptation to a prebiotic in the rumen ecosystem.

scholarly journals Antimicrobial and Antibiofilm Activity against Staphylococcus aureus of Opuntia ficus-indica (L.) Mill. Cladode Polyphenolic Extracts

Antioxidants ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 117 ◽  
Author(s):  
Federica Blando ◽  
Rossella Russo ◽  
Carmine Negro ◽  
Luigi De Bellis ◽  
Stefania Frassinetti
Keyword(s):  
Staphylococcus Aureus ◽  
Antioxidant Activity ◽  
Antioxidant Capacity ◽  
Biofilm Formation ◽  
Ex Vivo ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Total Phenolic ◽  
Antibiofilm Activity ◽  
Opuntia Ficus Indica

Plant extracts are a rich source of natural compounds with antimicrobial properties, which are able to prevent, at some extent, the growth of foodborne pathogens. The aim of this study was to investigate the potential of polyphenolic extracts from cladodes of Opuntia ficus-indica (L.) Mill. to inhibit the growth of some enterobacteria and the biofilm formation by Staphylococcus aureus. Opuntia ficus-indica cladodes at two stages of development were analysed for total phenolic content and antioxidant activity by Oxygen Radical Absorbance Capacity (ORAC) and Trolox equivalent antioxidant capacity (TEAC) (in vitro assays) and by cellular antioxidant activity in red blood cells (CAA-RBC) (ex vivo assay). The Liquid Chromatography Time-of-Flight Mass Spectrometry (LC/MS–TOF) analysis of the polyphenolic extracts revealed high levels of piscidic acid, eucomic acid, isorhamnetin derivatives and rutin, particularly in the immature cladode extracts. Opuntia cladodes extracts showed a remarkable antioxidant activity (in vitro and ex vivo), a selective inhibition of the growth of Gram-positive bacteria, and an inhibition of Staphylococcus aureus biofilm formation. Our results suggest and confirm that Opuntia ficus-indica cladode extracts could be employed as functional food, due to the high polyphenolic content and antioxidant capacity, and used as natural additive for food process control and food safety.

scholarly journals Candida albicans forms biofilms on the vaginal mucosa

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3635-3644 ◽  
Author(s):  
M. M. Harriott ◽  
E. A. Lilly ◽  
T. E. Rodriguez ◽  
P. L. Fidel ◽  
M. C. Noverr
Keyword(s):  
Biofilm Formation ◽  
Ex Vivo ◽  
Microscopic Analysis ◽  
Vaginal Mucosa ◽  
First Time ◽  
Established Role ◽  
Type Strains

Current understanding of resistance and susceptibility to vulvovaginal candidiasis challenges existing paradigms of host defence against fungal infection. While abiotic biofilm formation has a clearly established role during systemic Candida infections, it is not known whether C. albicans forms biofilms on the vaginal mucosa and the possible role of biofilms in disease. In vivo and ex vivo murine vaginitis models were employed to examine biofilm formation by scanning electron and confocal microscopy. C. albicans strains included 3153A (lab strain), DAY185 (parental control strain), and mutants defective in morphogenesis and/or biofilm formation in vitro (efg1/efg1 and bcr1/bcr1). Both 3153A and DAY815 formed biofilms on the vaginal mucosa in vivo and ex vivo as indicated by high fungal burden and microscopic analysis demonstrating typical biofilm architecture and presence of extracellular matrix (ECM) co-localized with the presence of fungi. In contrast, efg1/efg1 and bcr1/bcr1 mutant strains exhibited weak or no biofilm formation/ECM production in both models compared to wild-type strains and complemented mutants despite comparable colonization levels. These data show for the first time that C. albicans forms biofilms in vivo on vaginal epithelium, and that in vivo biotic biofilm formation requires regulators of biofilm formation (BCR1) and morphogenesis (EFG1).

scholarly journals Phage φAB6-Borne Depolymerase Combats Acinetobacter baumannii Biofilm Formation and Infection

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 279
Author(s):  
Md. Shahed-Al-Mahmud ◽  
Rakesh Roy ◽  
Febri Gunawan Sugiokto ◽  
Md. Nazmul Islam ◽  
Ming-Der Lin ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Capsular Polysaccharide ◽  
Foley Catheter ◽  
Inhibition Zone ◽  
Control Group ◽  
Bacterial Cells ◽  
Bacterial Lawn

Biofilm formation is one of the main causes of increased antibiotic resistance in Acinetobacter baumannii infections. Bacteriophages and their derivatives, such as tail proteins with depolymerase activity, have shown considerable potential as antibacterial or antivirulence agents against bacterial infections. Here, we gained insights into the activity of a capsular polysaccharide (CPS) depolymerase, derived from the tailspike protein (TSP) of φAB6 phage, to degrade A. baumannii biofilm in vitro. Recombinant TSP showed enzymatic activity and was able to significantly inhibit biofilm formation and degrade formed biofilms; as low as 0.78 ng, the inhibition zone can still be formed on the bacterial lawn. Additionally, TSP inhibited the colonization of A. baumannii on the surface of Foley catheter sections, indicating that it can be used to prevent the adhesion of A. baumannii to medical device surfaces. Transmission and scanning electron microscopy demonstrated membrane leakage of bacterial cells treated with TSP, resulting in cell death. The therapeutic effect of TSP in zebrafish was also evaluated and the results showed that the survival rate was significantly improved (80%) compared with that of the untreated control group (10%). Altogether, we show that TSP derived from φAB6 is expected to become a new antibiotic against multi-drug resistant A. baumannii and a biocontrol agent that prevents the formation of biofilms on medical devices.

scholarly journals Staphylococcus aureus cell wall structure and dynamics during host-pathogen interaction

2021 ◽  
Vol 17 (3) ◽  
pp. e1009468
Author(s):  
Joshua A. F. Sutton ◽  
Oliver T. Carnell ◽  
Lucia Lafage ◽  
Joe Gray ◽  
Jacob Biboy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Walls ◽  
Ex Vivo ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Bacterial Cells ◽  
Human Macrophages ◽  
Structure And Dynamics

Peptidoglycan is the major structural component of the Staphylococcus aureus cell wall, in which it maintains cellular integrity, is the interface with the host, and its synthesis is targeted by some of the most crucial antibiotics developed. Despite this importance, and the wealth of data from in vitro studies, we do not understand the structure and dynamics of peptidoglycan during infection. In this study we have developed methods to harvest bacteria from an active infection in order to purify cell walls for biochemical analysis ex vivo. Isolated ex vivo bacterial cells are smaller than those actively growing in vitro, with thickened cell walls and reduced peptidoglycan crosslinking, similar to that of stationary phase cells. These features suggested a role for specific peptidoglycan homeostatic mechanisms in disease. As S. aureus penicillin binding protein 4 (PBP4) has reduced peptidoglycan crosslinking in vitro its role during infection was established. Loss of PBP4 resulted in an increased recovery of S. aureus from the livers of infected mice, which correlated with enhanced fitness within murine and human macrophages. Thicker cell walls correlate with reduced activity of peptidoglycan hydrolases. S. aureus has a family of 4 putative glucosaminidases, that are collectively crucial for growth. Loss of the major enzyme SagB, led to attenuation during murine infection and reduced survival in human macrophages. However, loss of the other three enzymes Atl, SagA and ScaH resulted in clustering dependent attenuation, in a zebrafish embryo, but not a murine, model of infection. A combination of pbp4 and sagB deficiencies resulted in a restoration of parental virulence. Our results, demonstrate the importance of appropriate cell wall structure and dynamics during pathogenesis, providing new insight to the mechanisms of disease.

scholarly journals COMBINATORIAL EFFECT OF D-AMINOACIDS AND TETRACYCLINE AGAINST PSEUDOMONAS AERUGINOSA BIOFILM

2016 ◽  
Vol 8 (11) ◽  
pp. 216
Author(s):  
H. Jayalekshmi ◽  
C. Harikrishnan ◽  
Sajin Sali ◽  
N. Kaushik ◽  
Norin Mary G. Victus ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Wound Dressing ◽  
Ex Vivo ◽  
Multidrug Resistant ◽  
Antibiofilm Activity ◽  
Porcine Skin ◽  
Clinical Strains ◽  
Microtitre Plate Assay

Objective: The present study attempted to evaluate the anti-biofilm activity of D-amino acids (D-AAs) on Pseudomonas aeruginosa and determine if the combination of D-AAs with tetracycline enhances the anti-biofilm activity in vitro and ex vivo.Methods: Different D-AAs were tested for antibiofilm activity against wild type P. aeruginosa PAO1 and two multidrug resistant P. aeruginosa clinical strains in the presence of sub inhibitory concentrations of tetracycline using crystal violet microtitre plate assay. Results were further validated using in vitro wound dressing and ex vivo porcine skin models followed by cytotoxicity and hemocompatibility studies.Results: D-tryptophan (5 mmol) showed 61 % reduction in biofilm formation of P. aeruginosa. Interestingly combinatorial effect of 5 mmol D-tryptophan and 0.5 minimum inhibitory concentration (MIC) (7.5µg/ml) tetracycline showed 90% reduction in biofilm formation. 5 mmol D-methionine shows 28 % reduction and combination with tetracycline shows 41% reduction in biofilm formation of P. aeruginosa. D-leucine and D-tyrosine alone or in combination with tetracycline did not show significant anti-biofilm activity. D tryptophan-tetracycline combination could reduce 80 % and 77 % reduction in biofilm formation in two multi drug resistant P. aeruginosa clinical strains. D-tryptophan-tetracycline-combination could also reduce 76% and 66% reduction in biofilm formation in wound dressing model and porcine skin explant respectively. The cytotoxicity and hemocompatibility studies did not show significant toxicity when this combination was used.Conclusion: The results established the potential therapeutic application of D-tryptophan alone or in combination with tetracycline for treating biofilm associated clinical problems caused by P. aeruginosa.

scholarly journals S-Layer Protein Mediates the Stimulatory Effect of Lactobacillus helveticus MIMLh5 on Innate Immunity

2012 ◽  
Vol 79 (4) ◽  
pp. 1221-1231 ◽  
Author(s):  
Valentina Taverniti ◽  
Milda Stuknyte ◽  
Mario Minuzzo ◽  
Stefania Arioli ◽  
Ivano De Noni ◽  
...  
Keyword(s):  
Cell Line ◽  
Ex Vivo ◽  
Lactobacillus Helveticus ◽  
Human Macrophage ◽  
Mouse Bone Marrow ◽  
Similar Response ◽  
Bacterial Cells ◽  
Necrosis Factor Alpha ◽  
Anti Inflammatory

ABSTRACTThe ability to positively affect host health through the modulation of the immune response is a feature of increasing importance in measuring the probiotic potential of a bacterial strain. However, the identities of the bacterial cell components involved in cross talk with immune cells remain elusive. In this study, we characterized the dairy strainLactobacillus helveticusMIMLh5 and its surface-layer protein (SlpA) usingin vitroandex vivoanalyses. We found that MIMLh5 and SlpA exert anti-inflammatory effects by reducing the activation of NF-κB on the intestinal epithelial Caco-2 cell line. On the contrary, MIMLh5 and SlpA act as stimulators of the innate immune system by triggering the expression of proinflammatory factors tumor necrosis factor alpha and COX-2 in the human macrophage cell line U937 via recognition through Toll-like receptor 2. In the same experiments, SlpA protein did not affect the expression of the anti-inflammatory cytokine interleukin-10. A similar response was observed following stimulation of macrophages isolated from mouse bone marrow or the peritoneal cavity. These results suggest that SlpA plays a major role in mediating bacterial immune-stimulating activity, which could help to induce the host's defenses against and responses toward infections. This study supports the concept that the viability of bacterial cells is not always essential to exert immunomodulatory effects, thus permitting the development of safer therapies for the treatment of specific diseases according to a paraprobiotic intervention.

The role of microRNA in modulating myocardial ischemia-reperfusion injury

2011 ◽  
Vol 43 (10) ◽  
pp. 534-542 ◽  
Author(s):  
Yumei Ye ◽  
Jose R. Perez-Polo ◽  
Jinqiao Qian ◽  
Yochai Birnbaum
Keyword(s):  
Heart Disease ◽  
Reperfusion Injury ◽  
Fas Ligand ◽  
Ischemia Reperfusion Injury ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Therapeutic Targets ◽  
In Vitro Models

MicroRNAs (miRNAs) are small (∼22 nt) noncoding single-stranded RNA molecules that downregulate gene expression. Studies have shown that miRNAs control diverse aspects of heart disease, including hypertrophy, remodeling, heart failure, and arrhythmia. Recently, several studies have suggested that miRNAs contribute to ischemia-reperfusion injury by altering key signaling elements, thus making them potential therapeutic targets. By altering the expression of various key elements in cell survival and apoptosis [such as phosphoinositide 3-kinase (PI3K), phosphatase and tensin homolog deleted on chromosome 10 (PTEN), Bcl-2, Mcl-1, heat shock protein (HSP)60, HSP70, HSP20, programmed cell death 4 (Pdcd4), LRRFIP1, Fas ligand (FasL), Sirt-1, etc.], miRNAs alter the response to ischemia-reperfusion injury. Studies using various in vivo, ex vivo, and in vitro models have suggested the possible involvement of miR-1, miR-21, miR-29, miR-92a, miR-133, miR-199a, and miR-320 in ischemia-reperfusion injury and/or remodeling after myocardial infarction. Thus miRNAs could be potential therapeutic targets for the treatment of heart disease. Inhibiting miRNAs by antisense strategies or pharmacological approaches is likely to emerge as an alternative and safe method for conferring short- and intermediate-term protection against ischemia-reperfusion injury.

Activity of Metal-Azole Complexes Against Biofilms of Candida albicans and Candida glabrata

2020 ◽  
Vol 26 (14) ◽  
pp. 1524-1531 ◽  
Author(s):  
Livia D. Pereira ◽  
Taissa Vila ◽  
Luana P. Borba-Santos ◽  
Wanderley de Souza ◽  
Maribel Navarro ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Biofilm Formation ◽  
Candida Glabrata ◽  
Ex Vivo ◽  
Drug Efficacy ◽  
Ex Vivo Model ◽  
In Vitro Susceptibility ◽  
Poor Patient Compliance ◽  
Nail Infection

Background: Onychomycosis is a chronic nail infection caused by fungi frequently resistant to antifungal treatments. Recalcitrance in nail infections is a result of reduced antifungal penetration due to biofilm formation, combined with poor patient compliance with the treatment, which can be as long as 18 months. Objective: Metal-drug complexation is a widely used strategy to increase drug efficacy. Therefore, the aim of this work was to evaluate the antifungal and anti-biofilm activity of several metal-azole complexes against Candida albicans and Candida glabrata. Methods: Susceptibility assays and scanning electron microscopy were performed to determine the anti-biofilm activity of eight metal-azole complexes in vitro and ex-vivo, using human nail fragments. Results: In vitro susceptibility assays showed that complexation of both Au(I) and Zn(II) to clotrimazole and ketoconazole improved the anti-biofilm activity compared to the azole alone. Using an ex-vivo model of biofilm formation on fragments of human nails, we also demonstrate the improved efficacy of metal-azole complexes against biofilms of C. albicans and C. glabrata that resembles the onychomycosis structure. Noteworthy, biofilms of C. glabrata were more susceptible to the optimized complexes than those of C. albicans. Conclusion: In conclusion, metal-azole complexes used in this work show promising anti-biofilm activity and further clinical studies should confirm its potential for the treatment of Candida-associated onychomycosis.

Sign in / Sign up

Export Citation Format

Share Document