scholarly journals Functional and Structural Characterization of Pediococcus pentosaceus-Derived Biosurfactant and Its Biomedical Potential against Bacterial Adhesion, Quorum Sensing, and Biofilm Formation

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1371
Author(s):  
Mohd Adnan ◽  
Arif Jamal Siddiqui ◽  
Walid Sabri Hamadou ◽  
Syed Amir Ashraf ◽  
Md Imtaiyaz Hassan ◽  
...  
Keyword(s):  
Surface Tension ◽  
Pathogenic Bacteria ◽  
Cell Damage ◽  
Bacterial Cells ◽  
Environmental Friendliness ◽  
Pediococcus Pentosaceus ◽  
Emulsification Index ◽  
Biofilm Development ◽  
Biomedical Potential

Biosurfactants are surface-active molecules of microbial origin and alternatives to synthetic surfactants with various applications. Due to their environmental-friendliness, biocompatibility, biodegradability, effectiveness to work under various environmental conditions, and non-toxic nature, they have been recently recognized as potential agents with therapeutic and commercial importance. The biosurfactant produced by various probiotic lactic acid bacteria (LAB) has enormous applications in different fields. Thus, in vitro assessment of biofilm development prevention or disruption by natural biosurfactants derived from probiotic LAB is a plausible approach that can lead to the discovery of novel antimicrobials. Primarily, this study aims to isolate, screen, and characterize the functional and biomedical potential of biosurfactant synthesized by probiotic LAB Pediococcus pentosaceus (P. pentosaceus). Characterization consists of the assessment of critical micelle concentration (CMC), reduction in surface tension, and emulsification index (% EI24). Evaluation of antibacterial, antibiofilm, anti-QS, and anti-adhesive activities of cell-bound biosurfactants were carried out against different human pathogenic bacteria (B. subtilis, P. aeruginosa, S. aureus, and E. coli). Moreover, bacterial cell damage, viability of cells within the biofilm, and exopolysaccharide (EPS) production were also evaluated. As a result, P. pentosaceus was found to produce 4.75 ± 0.17 g/L biosurfactant, which displayed a CMC of 2.4 ± 0.68 g/L and reduced the surface tension from 71.11 ± 1.12 mN/m to 38.18 ± 0.58 mN/m. P. pentosaceus cells bound to the crude biosurfactant were found to be effective against all tested bacterial pathogens. It exhibited an anti-adhesion ability and impeded the architecture of the biofilm matrix by affecting the viability and integrity of bacterial cells within biofilms and reducing the total EPS content. Furthermore, the crude biosurfactant derived from P. pentosaceus was structurally characterized as a lipoprotein by GC-MS analysis, which confirms the presence of lipids and proteins. Thus, our findings represent the potent anti-adhesion and antibiofilm potential of P. pentosaceus crude biosurfactant for the first time, which may be explored further as an alternative to antibiotics or chemically synthesized toxic antibiofilm agents.

scholarly journals Non-Lytic Antibacterial Peptides That Translocate Through Bacterial Membranes to Act on Intracellular Targets

2019 ◽  
Vol 20 (19) ◽  
pp. 4877 ◽  
Author(s):  
Marlon H. Cardoso ◽  
Beatriz T. Meneguetti ◽  
Bruna O. Costa ◽  
Danieli F. Buccini ◽  
Karen G. N. Oshiro ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Synthesis ◽  
Pathogenic Bacteria ◽  
Biological Properties ◽  
Antibacterial Peptides ◽  
Bacterial Cells ◽  
Bacterial Membranes ◽  
Intracellular Targets

The advent of multidrug resistance among pathogenic bacteria has attracted great attention worldwide. As a response to this growing challenge, diverse studies have focused on the development of novel anti-infective therapies, including antimicrobial peptides (AMPs). The biological properties of this class of antimicrobials have been thoroughly investigated, and membranolytic activities are the most reported mechanisms by which AMPs kill bacteria. Nevertheless, an increasing number of works have pointed to a different direction, in which AMPs are seen to be capable of displaying non-lytic modes of action by internalizing bacterial cells. In this context, this review focused on the description of the in vitro and in vivo antibacterial and antibiofilm activities of non-lytic AMPs, including indolicidin, buforin II PR-39, bactenecins, apidaecin, and drosocin, also shedding light on how AMPs interact with and further translocate through bacterial membranes to act on intracellular targets, including DNA, RNA, cell wall and protein synthesis.

scholarly journals TSPphg Lysin from the Extremophilic Thermus Bacteriophage TSP4 as a Potential Antimicrobial Agent against Both Gram-Negative and Gram-Positive Pathogenic Bacteria

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 192 ◽  
Author(s):  
Feng Wang ◽  
Xinyu Ji ◽  
Qiupeng Li ◽  
Guanling Zhang ◽  
Jiani Peng ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Infection Model ◽  
Bacterial Cells ◽  
Skin Damage ◽  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative

New strategies against antibiotic-resistant bacterial pathogens are urgently needed but are not within reach. Here, we present in vitro and in vivo antimicrobial activity of TSPphg, a novel phage lysin identified from extremophilic Thermus phage TSP4 by sequencing its whole genome. By breaking down the bacterial cells, TSPphg is able to cause bacteria destruction and has shown bactericidal activity against both Gram-negative and Gram-positive pathogenic bacteria, especially antibiotic-resistant strains of Klebsiella pneumoniae, in which the complete elimination and highest reduction in bacterial counts by greater than 6 logs were observed upon 50 μg/mL TSPphg treatment at 37 °C for 1 h. A murine skin infection model further confirmed the in vivo efficacy of TSPphg in removing a highly dangerous and multidrug-resistant Staphylococcus aureus from skin damage and in accelerating wound closure. Together, our findings may offer a therapeutic alternative to help fight bacterial infections in the current age of mounting antibiotic resistance, and to shed light on bacteriophage-based strategies to develop novel anti-infectives.

scholarly journals UVC Light Prophylaxis for Cutaneous Wound Infections in Mice

2012 ◽  
Vol 56 (7) ◽  
pp. 3841-3848 ◽  
Author(s):  
Tianhong Dai ◽  
Barbara Garcia ◽  
Clinton K. Murray ◽  
Mark S. Vrahas ◽  
Michael R. Hamblin
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Light Exposure ◽  
Dna Lesions ◽  
Bacterial Cells ◽  
Wound Infections ◽  
Content Type ◽  
Cutaneous Wound ◽  
Thickness Skin

ABSTRACTUVC light has long been known to be highly germicidal but has not been much developed as a therapy for infections. This study investigated the potential of UVC light for the prophylaxis of infections developing in highly contaminated superficial cutaneous wounds.In vitrostudies demonstrated that the pathogenic bacteriaPseudomonas aeruginosaandStaphylococcus aureuswere inactivated at UVC light exposures much lower than those needed for a similar effect on mammalian keratinocytes. Mouse models of partial-thickness skin abrasions infected with bioluminescentP. aeruginosaandS. aureuswere developed. Approximately 107bacterial cells were inoculated onto wounds measuring 1.2 by1.2 cm on the dorsal surfaces of mice. UVC light was delivered at 30 min after bacterial inoculation. It was found that for both bacterial infections, UVC light at a single radiant exposure of 2.59 J/cm2reduced the bacterial burden in the infected mouse wounds by approximately 10-fold in comparison to those in untreated mouse wounds (P< 0.00001). Furthermore, UVC light increased the survival rate of mice infected withP. aeruginosaby 58.3% (P= 0.0023) and increased the wound healing rate in mice infected withS. aureusby 31.2% (P< 0.00001). DNA lesions were observed in the UVC light-treated mouse wounds; however, the lesions were extensively repaired by 48 h after UVC light exposure. These results suggested that UVC light may be used for the prophylaxis of cutaneous wound infections.

scholarly journals Identification of Quorum-Sensing Inhibitors Disrupting Signaling between Rgg and Short Hydrophobic Peptides in Streptococci

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Chaitanya Aggarwal ◽  
Juan Cristobal Jimenez ◽  
Hyun Lee ◽  
George E. Chlipala ◽  
Kiira Ratia ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Communication Networks ◽  
Drug Targets ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Chemical Compounds ◽  
Content Type ◽  
Hydrophobic Peptides ◽  
Biofilm Development

ABSTRACTBacteria coordinate a variety of social behaviors, important for both environmental and pathogenic bacteria, through a process of intercellular chemical signaling known as quorum sensing (QS). As microbial resistance to antibiotics grows more common, a critical need has emerged to develop novel anti-infective therapies, such as an ability to attenuate bacterial pathogens by means of QS interference. Rgg quorum-sensing pathways, widespread in the phylumFirmicutes, employ cytoplasmic pheromone receptors (Rgg transcription factors) that directly bind and elicit gene expression responses to imported peptide signals. In the human-restricted pathogenStreptococcus pyogenes, the Rgg2/Rgg3 regulatory circuit controls biofilm development in response to the short hydrophobic peptides SHP2 and SHP3. Using Rgg-SHP as a model receptor-ligand target, we sought to identify chemical compounds that could specifically inhibit Rgg quorum-sensing circuits. Individual compounds from a diverse library of known drugs and drug-like molecules were screened for their ability to disrupt complexes of Rgg and FITC (fluorescein isothiocyanate)-conjugated SHP using a fluorescence polarization (FP) assay. The best hits were found to bind Rgg3in vitrowith submicromolar affinities, to specifically abolish transcription of Rgg2/3-controlled genes, and to prevent biofilm development inS. pyogeneswithout affecting bacterial growth. Furthermore, the top hit, cyclosporine A, as well as its nonimmunosuppressive analog, valspodar, inhibited Rgg-SHP pathways in multiple species ofStreptococcus. The Rgg-FITC-peptide-based screen provides a platform to identify inhibitors specific for each Rgg type. Discovery of Rgg inhibitors constitutes a step toward the goal of manipulating bacterial behavior for purposes of improving health.IMPORTANCEThe global emergence of antibiotic-resistant bacterial infections necessitates discovery not only of new antimicrobials but also of novel drug targets. Since antibiotics restrict microbial growth, strong selective pressures to develop resistance emerge quickly in bacteria. A new strategy to fight microbial infections has been proposed, namely, development of therapies that decrease pathogenicity of invading organisms while not directly inhibiting their growth, thus decreasing selective pressure to establish resistance. One possible means to this goal is to interfere with chemical communication networks used by bacteria to coordinate group behaviors, which can include the synchronized expression of genes that lead to disease. In this study, we identified chemical compounds that disrupt communication pathways regulated by Rgg proteins in species ofStreptococcus. Treatment of cultures ofS. pyogeneswith the inhibitors diminished the development of biofilms, demonstrating an ability to control bacterial behavior with chemicals that do not inhibit growth.

scholarly journals Rhamnose Binding Protein as an Anti-Bacterial Agent—Targeting Biofilm of Pseudomonas aeruginosa

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 355 ◽  
Author(s):  
Tse-Kai Fu ◽  
Sim-Kun Ng ◽  
Yi-En Chen ◽  
Yuan-Chuan Lee ◽  
Fruzsina Demeter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Lung Epithelial Cells ◽  
Bacterial Agent ◽  
Lung Epithelial ◽  
Biofilm Development

More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.

scholarly journals Role of Multicellular Aggregates in Biofilm Formation

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Kasper N. Kragh ◽  
Jaime B. Hutchison ◽  
Gavin Melaugh ◽  
Chris Rodesney ◽  
Aled E. L. Roberts ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Single Cells ◽  
Subsequent Development ◽  
Relative Fitness ◽  
Bacterial Cells ◽  
Ecological Benefit ◽  
Multicellular Aggregates ◽  
Biofilm Development

ABSTRACT In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development of Pseudomonas aeruginosa biofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation. IMPORTANCE During the past decades, there has been a consensus around the model of development of a biofilm, involving attachment of single planktonic bacterial cells to a surface and the subsequent development of a mature biofilm. This study presents results that call for a modification of this rigorous model. We show how free floating biofilm aggregates can have a profound local effect on biofilm development when attaching to a surface. Our findings show that an aggregate landing on a surface will eventually outcompete the biofilm population arising from single cells attached around the aggregate and dominate the local biofilm development. These results point to a regime where preformed biofilm aggregates may have a fitness advantage over planktonic cells when it comes to accessing nutrients. Our findings add to the increasingly prominent comprehension that biofilm lifestyle is the default for bacteria and that planktonic single cells may be only a transition state at the most.

scholarly journals Antagonistic Effects of Lactobacillus plantarum on Candida albicans in ME-180 Cervical Carcinoma Cell Culture

2021 ◽  
Vol 13 (11) ◽  
Author(s):  
Young Sam Yuk ◽  
Young Ki Lee ◽  
Ga-Yeon Kim
Keyword(s):  
Candida Albicans ◽  
Lactobacillus Plantarum ◽  
Cervical Carcinoma ◽  
Defense Mechanisms ◽  
Pathogenic Bacteria ◽  
Early Stage ◽  
Cell Damage ◽  
Inhibitory Effects ◽  
Antagonistic Effects ◽  
Biofilm Development

Background: Candida albicans is an yeast species that colonizes the vaginal and oral mucosa of healthy women. However, it exhibits pathogenicity when the balance between yeast and mucous membranes and host defense mechanisms is disrupted. Objectives: To develop an auxiliary treatment for vaginitis, we evaluated the inhibitory effects of a probiotic bacterial strain isolated from kimchi on C. albicans. Methods: Lactobacillus plantarum, which exhibits potent inhibitory activity against pathogenic bacteria and is resistant to broad-spectrum antibiotics, was isolated from commercially kimchi in Korea, and its antagonistic effects on C. albicans were examined in a mixed culture with ME-180 cervical carcinoma cells. Results: Candida albicans caused extensive damage in ME-180 cells. In ME-180 cells inoculated with L. plantarum and then with C. albicans, the extent of cell damage increased as the concentration of the C. albicans culture increased. However, in ME-180 cells inoculated with L. plantarum at 106 CFU/mL or at a higher concentration, the extent of cell damage increased substantially with the concentration of C. albicans, indicating that L. plantarum inhibited the growth of C. albicans. Conclusions: Lactobacillus plantarum did not directly inhibit the growth of C. albicans but may have inhibited biofilm development at an early stage, thereby preventing the growth and mucosal adhesion of C. albicans. Further investigation of the safety, side effects, and metabolism of L. plantarum and its potential infectivity in animals is required before the L. plantarum isolate can be used to treat vaginitis.

scholarly journals Long-term social dynamics drive loss of function in pathogenic bacteria

2015 ◽  
Vol 112 (34) ◽  
pp. 10756-10761 ◽  
Author(s):  
Sandra Breum Andersen ◽  
Rasmus Lykke Marvig ◽  
Søren Molin ◽  
Helle Krogh Johansen ◽  
Ashleigh S. Griffin
Keyword(s):  
Social Interactions ◽  
Pathogenic Bacteria ◽  
Social Dynamics ◽  
Natural Populations ◽  
Population Level ◽  
Evolutionary Change ◽  
Bacterial Cells ◽  
Loss Of Function

Laboratory experiments show that social interactions between bacterial cells can drive evolutionary change at the population level, but significant challenges limit attempts to assess the relevance of these findings to natural populations, where selection pressures are unknown. We have increasingly sophisticated methods for monitoring phenotypic and genotypic dynamics in bacteria causing infectious disease, but in contrast, we lack evidence-based adaptive explanations for those changes. Evolutionary change during infection is often interpreted as host adaptation, but this assumption neglects to consider social dynamics shown to drive evolutionary change in vitro. We provide evidence to show that long-term behavioral dynamics observed in a pathogen are driven by selection to outcompete neighboring conspecific cells through social interactions. We find thatPseudomonas aeruginosabacteria, causing lung infections in patients with cystic fibrosis, lose cooperative iron acquisition by siderophore production during infection. This loss could be caused by changes in iron availability in the lung, but surprisingly, we find that cells retain the ability to take up siderophores produced by conspecifics, even after they have lost the ability to synthesize siderophores. Only when cooperative producers are lost from the population is the receptor for uptake lost. This finding highlights the potential pitfalls of interpreting loss of function in pathogenic bacterial populations as evidence for trait redundancy in the host environment. More generally, we provide an example of how sequence analysis can be used to generate testable hypotheses about selection driving long-term phenotypic changes of pathogenic bacteria in situ.

scholarly journals The Zebrafish Perivitelline Fluid Provides Maternally-Inherited Defensive Immunity

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1274
Author(s):  
Javiera F. De la Paz ◽  
Consuelo Anguita-Salinas ◽  
César Díaz-Celis ◽  
Francisco P. Chávez ◽  
Miguel L. Allende
Keyword(s):  
Pathogenic Bacteria ◽  
Protein Composition ◽  
In Silico Analysis ◽  
Edwardsiella Tarda ◽  
Bacterial Cells ◽  
In Vivo Experiments ◽  
Perivitelline Fluid ◽  
Protein Classes

In the teleost egg, the embryo is immersed in an extraembryonic fluid that fills the space between the embryo and the chorion and partially isolates it from the external environment, called the perivitelline fluid (PVF). The exact composition of the PVF remains unknown in vertebrate animals. The PVF allows the embryo to avoid dehydration, to maintain a safe osmotic balance and provides mechanical protection; however, its potential defensive properties against bacterial pathogens has not been reported. In this work, we determined the global proteomic profile of PVF in zebrafish eggs and embryos, and the maternal or zygotic origin of the identified proteins was studied. In silico analysis of PVF protein composition revealed an enrichment of protein classes associated with non-specific humoral innate immunity. We found lectins, protease inhibitors, transferrin, and glucosidases present from early embryogenesis until hatching. Finally, in vitro and in vivo experiments done with this fluid demonstrated that the PVF possessed a strong agglutinating capacity on bacterial cells and protected the embryos when challenged with the pathogenic bacteria Edwardsiella tarda. Our results suggest that the PVF is a primitive inherited immune extraembryonic system that protects the embryos from external biological threats prior to hatching.

scholarly journals Establishment of a Real-Time PCR-Based Approach for Accurate Quantification of Bacterial RNA Targets in Water, Using Salmonella as a Model Organism

2004 ◽  
Vol 70 (6) ◽  
pp. 3618-3623 ◽  
Author(s):  
Axel Fey ◽  
Stefan Eichler ◽  
S�bastien Flavier ◽  
Richard Christen ◽  
Manfred G. H�fle ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Target Genes ◽  
Model Organism ◽  
Housekeeping Genes ◽  
Environmental Water ◽  
Bacterial Cells ◽  
Rt Pcr ◽  
Rna Molecules ◽  
Accurate Quantification

ABSTRACT Quantitative PCR (Q-PCR) is a fast and efficient tool to quantify target genes. In eukaryotic cells, quantitative reverse transcription-PCR (Q-RT-PCR) is also used to quantify gene expression, with stably expressed housekeeping genes as standards. In bacteria, such stable expression of housekeeping genes does not occur, and the use of DNA standards leads to a broad underestimation. Therefore, an accurate quantification of RNA is feasible only by using appropriate RNA standards. We established and validated a Q-PCR method which enables the quantification of not only the number of copies of target genes (i.e., the number of bacterial cells) but also the number of RNA copies. The genes coding for InvA and the 16S rRNA of Salmonella enterica serovar Typhimurium were selected for the evaluation of the method. As DNA standards, amplified fragments of the target genes were used, whereas the same DNA standards were transcribed in vitro for the development of appropriate RNA standards. Salmonella cultures and environmental water samples inoculated with bacteria were then employed for the final testing. Both experimental approaches led to a sensitive, accurate, and reproducible quantification of the selected target genes and RNA molecules by Q-PCR and Q-RT-PCR. It is the first time that RNA standards have been successfully used for a precise quantification of the number of RNA molecules in prokaryotes. This demonstrates the potential of this approach for determining the presence and metabolic activity of pathogenic bacteria in environmental samples.

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