Effects of Copaifera duckei Dwyer oleoresin on the cell wall and cell division of Bacillus cereus

2013 ◽  
Vol 62 (7) ◽  
pp. 1032-1037 ◽  
Author(s):  
Elizabeth Cristina Gomes dos Santos ◽  
Claudio Luis Donnici ◽  
Elizabeth Ribeiro da Silva Camargos ◽  
Adriana Augusto de Rezende ◽  
Eloisa Helena de Aguiar Andrade ◽  
...  
Keyword(s):  
Cell Wall ◽  
Antibacterial Activity ◽  
Cell Division ◽  
Bacillus Cereus ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Bactericidal Action ◽  
Transmission Electron ◽  
Sds Page ◽  
Division Process

The aim of this work was to evaluate the antibacterial activity of Copaifera duckei oleoresin and to determine its possible mechanism of action against bacteria of clinical and food interest. The antibacterial activity was determined by agar diffusion and dilution methods; the mechanism of action by transmission electron microscopy and by SDS-PAGE; the bioactive compounds by bioautography; and the chemical analysis by GC/MS. Oleoresin showed activity against nine of the 11 strains of bacteria tested. Bacillus cereus was the most sensitive, with a MIC corresponding to 0.03125 mg ml−1 and with a bactericidal action. Oleoresin acted on the bacterial cell wall, removing proteins and the S-layer, and interfering with the cell-division process. This activity probably can be attributed to the action of terpenic compounds, among them the bisabolene compound. Gram-negative bacteria tested were not inhibited. C. duckei oleoresin is a potential antibacterial, suggesting that this oil could be used as a therapeutic alternative, mainly against B. cereus.

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

AUTORADIOGRAPHIC STUDIES OF BACTERIAL CELL WALL REPLICATION: I. CELL WALL GROWTH OF BACILLUS CEREUS IN THE PRESENCE OF CHLORAMPHENICOL

1967 ◽  
Vol 13 (4) ◽  
pp. 341-350 ◽  
Author(s):  
K. L. Chung
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Bacillus Cereus ◽  
First Generation ◽  
Third Generation ◽  
Cell Wall Synthesis ◽  
Daughter Cells ◽  
Entire Cell ◽  
Wall Growth ◽  
The Difference

The pattern of cell wall synthesis as measured by the incorporation of tritiated alanine into the cell wall of Bacillus cereus, and the number of synthesizing sites in the cell wall were studied by the direct and the reverse autoradiographic labelling methods.In the absence of chloramphenicol, the new cell wall was initiated at two or three segments, and later increased to four or five segments which continued to elongate but not to increase in number until the bacilli had made preparation for cell division. Shortly before the centripetal growth of the cell wall and constriction to separate daughter cells, two to three more new wall-segments were added to those already present. The second and third generation cells retained some old wall-segments from the first-generation mother, which remained as discrete clusters of grains, and could easily be distinguished from the new segments.In the presence of chloramphenicol, the new wall was initiated at 8 to 10 sites. Further incubation resulted in the uniform incorporation of labels at multiple sites along the entire cell length.The patterns of new wall replication as studied by the two methods were compared. To account for the difference in synthesizing sites when chloramphenicol is present, it is suggested that the cells have either used the maximum number of sites or have completely bypassed all the sites and allowed the tritiated alanine to diffuse into the wall to become incorporated.

Antibacterial activity of a microemulsion loaded with cephalosporin

Biologia ◽  
2016 ◽  
Vol 71 (7) ◽  
Author(s):  
Mayson H. Alkhatib ◽  
Magda M. Aly ◽  
Ohud A. Saleh ◽  
Hana M. Gashlan
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Activities ◽  
Distilled Water ◽  
Gram Negative Bacteria ◽  
Food Technology ◽  
Cremophor El ◽  
Gram Negative ◽  
Transmission Electron ◽  
Pharmaceutical Industries ◽  
Ethyl Decanoate

AbstractMicroemulsions (MEs), isotropic mixture of water, oil, surfactant and most frequently cosurfactant, have gained great interest in the pharmaceutical industries and food technology due to their great potential to act as antimicrobials as well as nanocarriers for antibiotics. In this study, the antibacterial activities of a ME, composed of 23.5% Cremophor EL, 12.5% transcutol, 30% ethyl decanoate and 34% distilled water, against Gram-positive and Gram-negative bacteria and its potential as a nanocarrier for cephalosporine (CEPH/ME) were assessed. The morphological structures of the ME and CEPH/ME, revealed by transmission electron microscopy, were spherical and their droplet diameters were 15.55 ± 3.17 nm and 10.56 ± 2.32 nm, respectively. ME was found to have great antibacterial activity against

Acid and alkaline phosphatases of Capnocytophaga species. III. The relationship of the enzymes to the cell wall

1983 ◽  
Vol 29 (10) ◽  
pp. 1369-1381 ◽  
Author(s):  
Thomas P. Poirier ◽  
Stanley C. Holt
Keyword(s):  
Cell Wall ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Marker Enzyme ◽  
Transmission Electron ◽  
Sds Page ◽  
Triton X ◽  
Relationship Of ◽  
The Relationship ◽  
Cell Fragments

Acid (AcP) and alkaline phosphatase (AlP) were localized by physicobiochemical techniques. Greater than 53% of the phosphatases were detected, following sonication, in a low speed centrifugation pellet while osmotically shocked and spheroplasted Capnocytophaga species released only 9–28% and 11–43% of the cellular phosphatases, respectively. French pressure cell disruption was more effective in releasing the phosphatases. Cell fragments were separated into cell wall, cytoplasmic membrane, and soluble fractions as determined by marker enzyme, chemical composition, transmission electron microscopy, sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS–PAGE) protein analysis, and gel diffusion. AcP and AlP was partitioned between the isolated cell wall (31–46%) and soluble material (33–61%), with greater than 60% of the phosphatases remaining with the cell wall following Triton X-100 treatment. The amount of phosphatase at the surface of intact C. ochracea was quantitated by specific 125I-protein labelling.

scholarly journals Antibacterial mechanism of rhodomyrtone involves the disruption of nucleoid segregation checkpoint in Streptococcus suis

2020 ◽  
Author(s):  
Apichaya Traithan ◽  
Pongsri Tongtawe ◽  
Jeeraphong Thanongsaksrikul ◽  
Supayang Voravuthikunchai ◽  
Potjanee Sriman
Keyword(s):  
Cell Division ◽  
Early Stage ◽  
Streptococcus Suis ◽  
Transmission Electron Micrograph ◽  
Antibacterial Mechanism ◽  
Bacterial Cell Division ◽  
Transmission Electron ◽  
Inhibition Concentration ◽  
Division Process ◽  
Z Ring

Abstract Rhodomyrtone has been recently demonstrated to possess a novel antibiotic mechanism of action against Gram-positive bacteria which involves multiple targets, resulting in the interference of several bacterial biological processes including cell division. The present study aims to closely look at the downstream effect of rhodomyrtone treatment on nucleoid segregation in Streptococcus suis, an important zoonotic pathogen. Minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values of rhodomyrtone against recombinant S. suis ParB-GFP, a nucleoid segregation reporter strain, were 0.5 and 1 µg/ml, respectively, equivalent to the potency of vancomycin. Using fluorescence live-cell imaging, we demonstrated that rhodomyrtone at 2 × MIC caused incomplete nucleoid segregation and septum misplacement, leading to the generation of anucleated cells. FtsZ immune-staining of rhodomyrtone-treated S. suis for 30 min revealed that although large amount of FtsZ was trapped in the region of high fluidity membrane, it appeared to be able to polymerize to form a complete Z-ring. However, the Z-ring was shifted away from midcell. Transmission electron micrograph further confirmed disruption of nucleoid segregation and septum misplacement at 120 min following rhodomyrtone treatment. Asymmetric septum formation resulted in either generation of minicells without nucleoid, septum formed over incomplete segregated nucleoid (guillotine effect), or formation of multi-constriction of Z-ring within a single cell. This finding spotlights on antibacterial mechanism of rhodomyrtone involves the early stage in bacterial cell division process.

scholarly journals Genetic interaction mapping highlights key roles of the Tol-Pal complex

2021 ◽  
Author(s):  
Wee Boon Tan ◽  
Shu-Sin Chng
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Genetic Interaction ◽  
Strong Interactions ◽  
Growth Defects ◽  
Transposon Insertion ◽  
Complex Functions ◽  
Division Process ◽  
Transposon Insertion Sequencing ◽  
Periplasmic Glucan

AbstractThe conserved Tol-Pal trans-envelope complex is important for outer membrane (OM) stability and cell division in Gram-negative bacteria. It has been proposed to mediate OM constriction during cell division via tethering to the cell wall. Yet, recent studies suggest that the complex has additional roles in OM lipid homeostasis and septal cell wall separation. How the Tol-Pal complex functions to facilitate these many processes is unclear. To gain insights into its role(s), we applied transposon insertion sequencing, and report here a detailed network of genetic interactions with the tol-pal locus in Escherichia coli. We found one positive and >20 negative strong interactions based on fitness. Disruption of genes responsible for osmoregulated periplasmic glucan biosynthesis restores fitness and OM barrier function, but not cell division defects, in tol-pal mutants. In contrast, deletions of genes involved in OM homeostasis and cell wall remodelling give rise to synthetic growth defects in strains lacking Tol-Pal, especially exacerbating OM barrier and/or cell division defects. Notably, the ΔtolA mutant having additional defects in OM protein assembly (ΔbamB) exhibited severe division phenotypes, even under conditions where the single mutants divide normally; this highlights the possibility for OM phenotypes to indirectly influence the cell division process. Overall, our work provides insights into the intricate nature of Tol-Pal function, and reinforces the model that this complex plays crucial roles in cell wall-OM tethering, cell wall remodelling, and in particular, OM homeostasis.

scholarly journals Unveiling the Mechanism of Action of 7α-acetoxy-6β-hydroxyroyleanone on an MRSA/VISA Strain: Membrane and Cell Wall Interactions

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 983
Author(s):  
Filipe Pereira ◽  
Teresa Figueiredo ◽  
Rodrigo F. M. de Almeida ◽  
Catarina A. C. Antunes ◽  
Catarina Garcia ◽  
...  
Keyword(s):  
Cell Wall ◽  
Antibacterial Activity ◽  
Lipid Bilayers ◽  
Mechanism Of Action ◽  
Resistant Bacteria ◽  
High Antibacterial Activity ◽  
Cell Wall Disruption ◽  
Low Cytotoxicity ◽  
Mrsa Strains ◽  
Interesting Alternative

The number of cases of failure in the treatment of infections associated with resistant bacteria is on the rise, due to the decreasing efficacy of current antibiotics. Notably, 7α-Acetoxy-6β-hydroxyroyleanone (AHR), a diterpene isolated from different Plectranthus species, showed antibacterial activity, namely against Methicillin-resistant Staphylococcus aureus (MRSA) strains. The high antibacterial activity and low cytotoxicity render this natural compound an interesting alternative against resistant bacteria. The aim of this study is to understand the mechanism of action of AHR on MRSA, using the MRSA/Vancomycin-intermediate S. aureus (VISA) strain CIP 106760, and to study the AHR effect on lipid bilayers and on the cell wall. Although AHR interacted with lipid bilayers, it did not have a significant effect on membrane passive permeability. Alternatively, bacteria treated with this royleanone displayed cell wall disruption, without revealing cell lysis. In conclusion, the results gathered so far point to a yet undescribed mode of action that needs further investigation.

scholarly journals Antibacterial mechanism of rhodomyrtone involves the disruption of nucleoid segregation checkpoint in Streptococcus suis

2020 ◽  
Author(s):  
Apichaya Traithan ◽  
Pongsri Tongtawe ◽  
Jeeraphong Thanongsaksrikul ◽  
Supayang Voravuthikunchai ◽  
Potjanee Sriman
Keyword(s):  
Cell Division ◽  
Early Stage ◽  
Streptococcus Suis ◽  
Antibacterial Mechanism ◽  
Bacterial Cell Division ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Inhibition Concentration ◽  
Division Process ◽  
Z Ring

Abstract Rhodomyrtone has been recently demonstrated to possess a novel antibiotic mechanism of action against Gram-positive bacteria which involved the multiple targets, resulting in the interference of several bacterial biological processes including the cell division. The present study aims to closely look at the downstream effect of rhodomyrtone treatment on nucleoid segregation in Streptococcus suis, an important zoonotic pathogen. The minimum inhibition concentration (MIC) and the minimum bactericidal concentration (MBC) values of rhodomyrtone against the recombinant S. suis ParB-GFP, a nucleoid segregation reporter strain, were 0.5 and 1 µg/ml, respectively, which were equivalent to the potency of vancomycin. Using the fluorescence live-cell imaging, we demonstrated that rhodomyrtone at 2 × MIC caused incomplete nucleoid segregation and septum misplacement, leading to the generation of anucleated cells. FtsZ immune-staining of rhodomyrtone-treated S. suis for 30 min revealed that the large amount of FtsZ was trapped in the region of high fluidity membrane and appeared to be able to polymerize to form a complete Z-ring. However, the Z-ring was shifted away from the midcell. Transmission electron microscopy further confirmed the disruption of nucleoid segregation and septum misplacement at 120 min following the rhodomyrtone treatment. Asymmetric septum formation resulted in either generation of minicells without nucleoid, septum formed over incomplete segregated nucleoid (guillotine effect), or formation of multi-constriction of Z-ring within a single cell. This finding spotlights on antibacterial mechanism of rhodomyrtone involves the early stage in bacterial cell division process.

scholarly journals Fungal Cell Wall Septation and Cytokinesis Are Inhibited by Bleomycins

2003 ◽  
Vol 47 (10) ◽  
pp. 3281-3289 ◽  
Author(s):  
Carol W. Moore ◽  
Judith McKoy ◽  
Robert Del Valle ◽  
Donald Armstrong ◽  
Edward M. Bernard ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Division ◽  
Cell Walls ◽  
Intact Cell ◽  
Fungal Growth ◽  
Fungal Cell ◽  
Transmission Electron ◽  
Mother And Daughter ◽  
Fungal Organisms

ABSTRACT When the essential and distinctive cell walls of either pathogenic or nonpathogenic fungi break, cytoplasmic membranes rupture and fungi die. This fungicidal activity was discovered previously on nonproliferating Saccharomyces cerevisiae cells treated briefly with the oxidative tool and anticancer drug family of bleomycins. The present studies investigated effects of bleomycin on growing fungal organisms. These included the medically important Aspergillus fumigatus and Cryptococcus neoformans, as well as the emerging human pathogen and fungal model, S. cerevisiae. Bleomycin had its highest potency against A. fumigatus. Scanning electron microscopy and thin-section transmission electron microscopy were used to study morphological growth characteristics. Killing and growth inhibition were also measured. Long, thin, and segmented hyphae were observed when A. fumigatus was grown without bleomycin but were never observed when the mold was grown with the drug. Bleomycin arrested conidial germination, hyphal development, and the progression and completion of cell wall septation. Similarly, the drug inhibited the construction of yeast cell wall septa, preventing cytokinesis and progression in the cell division cycle of S. cerevisiae. Even when cytoplasms of mother and daughter cells separated, septation and cell division did not necessarily occur. Bizarre cell configurations, abnormally thickened cell walls at mother-daughter necks, abnormal polarized growth, large undivided cells, fragmented cells, and empty cell ghosts were also produced. This is the first report of a fungicidal agent that arrests fungal growth and development, septum formation, and cytokinesis and that also preferentially localizes to cell walls and alters isolated cell walls as well as intact cell walls on nongrowing cells.

scholarly journals Bacterial Growth and Cell Division: a Mycobacterial Perspective

2008 ◽  
Vol 72 (1) ◽  
pp. 126-156 ◽  
Author(s):  
Erik C. Hett ◽  
Eric J. Rubin
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Active Tuberculosis ◽  
Gram Negative Bacteria ◽  
Complex Cell ◽  
Causative Agents ◽  
The Many ◽  
Mycobacterial Cell Wall ◽  
Wall Components ◽  
Normal Architecture

SUMMARY The genus Mycobacterium is best known for its two major pathogenic species, M. tuberculosis and M. leprae, the causative agents of two of the world's oldest diseases, tuberculosis and leprosy, respectively. M. tuberculosis kills approximately two million people each year and is thought to latently infect one-third of the world's population. One of the most remarkable features of the nonsporulating M. tuberculosis is its ability to remain dormant within an individual for decades before reactivating into active tuberculosis. Thus, control of cell division is a critical part of the disease. The mycobacterial cell wall has unique characteristics and is impermeable to a number of compounds, a feature in part responsible for inherent resistance to numerous drugs. The complexity of the cell wall represents a challenge to the organism, requiring specialized mechanisms to allow cell division to occur. Besides these mycobacterial specializations, all bacteria face some common challenges when they divide. First, they must maintain their normal architecture during and after cell division. In the case of mycobacteria, that means synthesizing the many layers of complex cell wall and maintaining their rod shape. Second, they need to coordinate synthesis and breakdown of cell wall components to maintain integrity throughout division. Finally, they need to regulate cell division in response to environmental stimuli. Here we discuss these challenges and the mechanisms that mycobacteria employ to meet them. Because these organisms are difficult to study, in many cases we extrapolate from information known for gram-negative bacteria or more closely related GC-rich gram-positive organisms.

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