scholarly journals Curvulin and Phaeosphaeride A from Paraphoma sp. VIZR 1.46 Isolated from Cirsium arvense as Potential Herbicides

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2795 ◽  
Author(s):  
Ekaterina Poluektova ◽  
Yuriy Tokarev ◽  
Sofia Sokornova ◽  
Leonid Chisty ◽  
Antonio Evidente ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Herbicidal Activity ◽  
Cirsium Arvense ◽  
Gram Negative Bacteria ◽  
Active Metabolites ◽  
Solid Culture ◽  
Gram Negative ◽  
Natural Origin ◽  
Phytotoxic Activity ◽  
First Time

Phoma-like fungi are known as producers of diverse spectrum of secondary metabolites, including phytotoxins. Our bioassays had shown that extracts of Paraphoma sp. VIZR 1.46, a pathogen of Cirsium arvense, are phytotoxic. In this study, two phytotoxically active metabolites were isolated from Paraphoma sp. VIZR 1.46 liquid and solid cultures and identified as curvulin and phaeosphaeride A, respectively. The latter is reported also for the first time as a fungal phytotoxic product with potential herbicidal activity. Both metabolites were assayed for phytotoxic, antimicrobial and zootoxic activities. Curvulin and phaeosphaeride A were tested on weedy and agrarian plants, fungi, Gram-positive and Gram-negative bacteria, and on paramecia. Curvulin was shown to be weakly phytotoxic, while phaeosphaeride A caused severe necrotic lesions on all the tested plants. To evaluate phaeosphaeride A’s herbicidal efficacy, the phytotoxic activity of this compound in combination with five different adjuvants was studied. Hasten at 0.1% (v/v) was found to be the most potent and compatible adjuvant, and its combination with 0.5% (v/v) semi-purified extract of Paraphoma sp. VIZR 1.46 solid culture exhibited maximum damage to C. arvense plants. These findings may offer significant importance for further investigation of herbicidal potential of phaeosphaeride A and possibly in devising new herbicide of natural origin.

scholarly journals The antimicrobial potential of cannabidiol

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mark A. T. Blaskovich ◽  
Angela M. Kavanagh ◽  
Alysha G. Elliott ◽  
Bing Zhang ◽  
Soumya Ramu ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Modern Medicine ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
New Class ◽  
Clostridioides Difficile ◽  
Excellent Activity ◽  
Induce Resistance ◽  
First Time

AbstractAntimicrobial resistance threatens the viability of modern medicine, which is largely dependent on the successful prevention and treatment of bacterial infections. Unfortunately, there are few new therapeutics in the clinical pipeline, particularly for Gram-negative bacteria. We now present a detailed evaluation of the antimicrobial activity of cannabidiol, the main non-psychoactive component of cannabis. We confirm previous reports of Gram-positive activity and expand the breadth of pathogens tested, including highly resistant Staphylococcus aureus, Streptococcus pneumoniae, and Clostridioides difficile. Our results demonstrate that cannabidiol has excellent activity against biofilms, little propensity to induce resistance, and topical in vivo efficacy. Multiple mode-of-action studies point to membrane disruption as cannabidiol’s primary mechanism. More importantly, we now report for the first time that cannabidiol can selectively kill a subset of Gram-negative bacteria that includes the ‘urgent threat’ pathogen Neisseria gonorrhoeae. Structure-activity relationship studies demonstrate the potential to advance cannabidiol analogs as a much-needed new class of antibiotics.

Ultrastructural studies of Chlamydia psittaci 6BC variant strains. I. Ultrastructure of the surface layers of egg-passaged 6BC strain

1973 ◽  
Vol 19 (8) ◽  
pp. 887-894
Author(s):  
Linda Poffenroth ◽  
J. W. Costerton ◽  
Nonna Kordová ◽  
John C. Wilt
Keyword(s):  
Chick Embryo ◽  
Microscopic Examination ◽  
Electron Microscopic Examination ◽  
Chlamydia Psittaci ◽  
Gram Negative Bacteria ◽  
Surface Layers ◽  
Electron Microscopic ◽  
Gram Negative ◽  
Ultrastructural Studies ◽  
First Time

Electron microscopic examination of a semipurified Chlamydia psittaci 6BC strain attenuated in chick embryo yolk sac revealed for the first time two morphologically distinct small elementary bodies which differ both in the ultrastructure of their surface layers and in their buoyant densities in sucrose gradients. Also, the morphology of the surface layers of the larger reticulate forms in cell-free systems is described for the first time. Many points of difference between the surface envelopes and internal structure of chlamydial particles and those of Gram-negative bacteria are discussed.

scholarly journals Shadowing the Actions of a Predator: Backlit Fluorescent Microscopy Reveals Synchronous Nonbinary Septation of Predatory Bdellovibrio inside Prey and Exit through Discrete Bdelloplast Pores

2010 ◽  
Vol 192 (24) ◽  
pp. 6329-6335 ◽  
Author(s):  
A. K. Fenton ◽  
M. Kanna ◽  
R. D. Woods ◽  
S.-I. Aizawa ◽  
R. E. Sockett
Keyword(s):  
Cell Division ◽  
Outer Membrane ◽  
Fluorescent Microscopy ◽  
Gram Negative Bacteria ◽  
Bacterial Cell Division ◽  
Prey Cell ◽  
Gram Negative ◽  
A Genome ◽  
Predatory Bacteria ◽  
First Time

ABSTRACT The Bdellovibrio are miniature “living antibiotic” predatory bacteria which invade, reseal, and digest other larger Gram-negative bacteria, including pathogens. Nutrients for the replication of Bdellovibrio bacteria come entirely from the digestion of the single invaded bacterium, now called a bdelloplast, which is bound by the original prey outer membrane. Bdellovibrio bacteria are efficient digesters of prey cells, yielding on average 4 to 6 progeny from digestion of a single prey cell of a genome size similar to that of the Bdellovibrio cell itself. The developmental intrabacterial cycle of Bdellovibrio is largely unknown and has never been visualized “live.” Using the latest motorized xy stage with a very defined z-axis control and engineered periplasmically fluorescent prey allows, for the first time, accurate return and visualization without prey bleaching of developing Bdellovibrio cells using solely the inner resources of a prey cell over several hours. We show that Bdellovibrio bacteria do not follow the familiar pattern of bacterial cell division by binary fission. Instead, they septate synchronously to produce both odd and even numbers of progeny, even when two separate Bdellovibrio cells have invaded and develop within a single prey bacterium, producing two different amounts of progeny. Evolution of this novel septation pattern, allowing odd progeny yields, allows optimal use of the finite prey cell resources to produce maximal replicated, predatory bacteria. When replication is complete, Bdellovibrio cells exit the exhausted prey and are seen leaving via discrete pores rather than by breakdown of the entire outer membrane of the prey.

Fusobacterium nucleatum, the first Gram-negative bacterium demonstrated to produce polyglutamate

2009 ◽  
Vol 55 (5) ◽  
pp. 627-632 ◽  
Author(s):  
Thomas Candela ◽  
Marie Moya ◽  
Michel Haustant ◽  
Agnès Fouet
Keyword(s):  
In Silico Analysis ◽  
Fusobacterium Nucleatum ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
The Third ◽  
Gram Negative Organisms ◽  
First Time

Poly-γ-glutamate has been described in many Gram-positive organisms. When anchored to the surface, it is a capsule and as such a virulence factor. Based on sequence similarities, few Gram-negative organisms have been suggested to synthesize poly-γ-glutamate. For the first time, a Gram-negative bacterium, Fusobacterium nucleatum , is shown to produce and secrete poly-γ-glutamate. Putative poly-γ-glutamate-synthesizing genes from Gram-negative organisms have been compared with their Gram-positive homologs by in silico analysis, i.e., gene sequence and phylogenetic analysis. Clusters of three instead of four genes were highlighted by our screen. The products of the first two genes display similarity with their Gram-positive equivalents, yet the sequences from the Gram-negative organisms can be distinguished from those of the Gram-positives. Interestingly, the sequence of the predicted product of the third gene is conserved among Gram-negative bacteria but displays no similarity to that of either the third or fourth gene of the Gram-positive operons. It is suggested that, like for Gram-positive bacteria, poly-γ-glutamate has a role in virulence for pathogens and one in survival for other Gram-negative bacteria.

Antimicrobial Activity of Gentiana lutea L. Extracts

2009 ◽  
Vol 64 (5-6) ◽  
pp. 339-342 ◽  
Author(s):  
Katarina Šavikin ◽  
Nebojša Menković ◽  
Gordana Zdunić ◽  
Tatjana Stević ◽  
Dragoja Radanović ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Secondary Metabolites ◽  
Antimicrobial Effect ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Gram Negative ◽  
Gentiana Lutea ◽  
Methanolic Extracts ◽  
Pure Compounds

Methanolic extracts of flowers and leaves of Gentiana lutea L., together with the isolated compounds mangiferin, isogentisin and gentiopicrin, were used to investigate the antimicrobial activity of the plant. A variety of Gram-positive and Gram-negative bacteria as well as the yeast Candida albicans has been included in this study. Both extracts and isolated compounds showed antimicrobial activity with MIC values ranging from 0.12 - 0.31 mg/ml. Our study indicated that the synergistic activity of the pure compounds may be responsible for the good antimicrobial effect of the extracts. Quantification of the secondary metabolites was performed using HPLC

scholarly journals Novel Modifications of Nonribosomal Peptides from Brevibacillus laterosporus MG64 and Investigation of Their Mode of Action

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Zhibo Li ◽  
Reinder H. de Vries ◽  
Parichita Chakraborty ◽  
Chunxu Song ◽  
Xinghong Zhao ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Secondary Metabolites ◽  
Cell Membrane ◽  
Synergistic Effect ◽  
Mode Of Action ◽  
Nonribosomal Peptides ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Brevibacillus Laterosporus ◽  
Reductase Domain

ABSTRACT Nonribosomal peptides (NRPs) are a class of secondary metabolites usually produced by microorganisms. They are of paramount importance in different applications, including biocontrol and pharmacy. Brevibacillus spp. are a rich source of NRPs yet have received little attention. In this study, we characterize four novel bogorol variants (bogorols I to L, cationic linear lipopeptides) and four succilins (succilins I to L, containing a succinyl group that is attached to the Orn3/Lys3 in bogorols I to L) from the biocontrol strain Brevibacillus laterosporus MG64. Further investigation revealed that the bogorol family of peptides employs an adenylation pathway for lipoinitiation, different from the usual pattern, which is based on an external ligase and coenzyme A. Moreover, the formation of valinol was proven to be mediated by a terminal reductase domain and a reductase encoded by the bogI gene. Furthermore, succinylation, which is a novel type of modification in the family of bogorols, was discovered. Its occurrence requires a high concentration of the substrate (bogorols), but its responsible enzyme remains unknown. Bogorols display potent activity against both Gram-positive and Gram-negative bacteria. Investigation of their mode of action reveals that bogorols form pores in the cell membrane of both Gram-positive and Gram-negative bacteria. The combination of bogorols and relacidines, another class of NRPs produced by B. laterosporus MG64, displays a synergistic effect on different pathogens, suggesting the great potential of both peptides as well as their producer B. laterosporus MG64 for broad applications. Our study provides a further understanding of the bogorol family of peptides as well as their applications. IMPORTANCE NRPs form a class of secondary metabolites with biocontrol and pharmaceutical potential. This work describes the identification of novel bogorol variants and succinylated bogorols (namely, succilins) and further investigates their biosynthetic pathway and mode of action. Adenylation domain-mediated lipoinitiation of bogorols represents a novel pathway by which NRPs incorporate fatty acid tails. This pathway provides the possibility to engineer the lipid tail of NRPs without identifying a fatty acid coenzyme ligase, which is usually not present in the biosynthetic gene cluster. The terminal reductase domain (TD) and BogI-mediated valinol formation and their effect on the biological activity of bogorols are revealed. Succinylation, which is rarely reported in NRPs, was discovered in the bogorol family of peptides. We demonstrate that bogorols combat bacterial pathogens by forming pores in the cell membrane. We also report the synergistic effect of two natural products (relacidine B and bogorol K) produced by the same strain, which is relevant for competition for a niche.

scholarly journals Antiadherent and Antibiofilm Activity ofHumulus lupulusL. Derived Products: New Pharmacological Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Marcin Rozalski ◽  
Bartlomiej Micota ◽  
Beata Sadowska ◽  
Anna Stochmal ◽  
Dariusz Jedrejek ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Culture Medium ◽  
Antimicrobial Properties ◽  
Antibiofilm Activity ◽  
Pharmacological Properties ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Abiotic Surfaces ◽  
First Time ◽  
Plant Compounds

New antimicrobial properties of products derived fromHumulus lupulusL. such as antiadherent and antibiofilm activities were evaluated. The growth of gram-positive but not gram-negative bacteria was inhibited to different extents by these compounds. An extract of hop cones containing 51% xanthohumol was slightly less active againstS. aureusstrains (MIC range 31.2–125.0 μg/mL) than pure xanthohumol (MIC range 15.6–62.5 μg/mL). The spent hop extract, free of xanthohumol, exhibited lower but still relevant activity (MIC range 1-2 mg/mL). There were positive coactions of hop cone, spent hop extracts, and xanthohumol with oxacillin against MSSA and with linezolid against MSSA and MRSA. Plant compounds in the culture medium at sub-MIC concentrations decreased the adhesion ofStaphylococcito abiotic surfaces, which in turn caused inhibition of biofilm formation. The rate of mature biofilm eradication by these products was significant. The spent hop extract at MIC reduced biofilm viability by 42.8%, the hop cone extract by 74.8%, and pure xanthohumol by 86.5%. When the hop cone extract or xanthohumol concentration was increased, almost complete biofilm eradication was achieved (97–99%). This study reveals the potent antibiofilm activity of hop-derived compounds for the first time.

scholarly journals Enterobacterial Repetitive Intergenic Consensus Sequences as Molecular Targets for Typing of Mycobacterium tuberculosis Strains

1998 ◽  
Vol 36 (1) ◽  
pp. 128-132 ◽  
Author(s):  
Leonardo A. Sechi ◽  
Stefania Zanetti ◽  
Ilaria Dupré ◽  
Giovanni Delogu ◽  
Giovanni Fadda
Keyword(s):  
Genetic Diversity ◽  
Mycobacterium Tuberculosis ◽  
Molecular Targets ◽  
Clinical Isolates ◽  
Gram Negative Bacteria ◽  
Enterobacterial Repetitive Intergenic Consensus ◽  
Gram Negative ◽  
Consensus Sequences ◽  
First Time

The presence of enterobacterial repetitive intergenic consensus (ERIC) sequences was demonstrated for the first time in the genome ofMycobacterium tuberculosis; these sequences have been found in transcribed regions of the chromosomes of gram-negative bacteria. In this study genetic diversity among clinical isolates of M. tuberculosis was determined by PCR with ERIC primers (ERIC-PCR). The study isolates comprised 71 clinical isolates collected from Sardinia, Italy. ERIC-PCR was able to identify 59 distinct profiles. The results obtained were compared with IS6110 and PCR-GTG fingerprinting. We found that the level of differentiation obtained by ERIC-PCR is greater than that obtained by IS6110fingerprinting and comparable to that obtained by PCR-GTG. This method of fingerprinting is rapid and sensitive and can be applied to the study of the epidemiology of M. tuberculosis infections, especially when IS6110 fingerprinting is not of any help.

Evaluating H2O2 in Living Bacteria by Ratiometric Fluorescent Probe

2022 ◽  
Vol 905 ◽  
pp. 210-217
Author(s):  
Qian Qian Chen
Keyword(s):  
Fluorescent Probe ◽  
Living Cells ◽  
Gram Negative Bacteria ◽  
Signal Molecule ◽  
Gram Negative ◽  
Key Factor ◽  
Live Bacteria ◽  
First Time ◽  
Living Bacteria ◽  
Ratiometric Fluorescent Probe

Hydrogen peroxide (H2O2) is a significant signal molecule in physiological and pathological processes. Levels of H2O2 in bacteria are proved to be a key factor in immune response. To sum up, detection of H2O2 levels in living bacteria is remarkable for further study of its physiological and pathological effects. Herein, we propose a novel ratiometric fluorescent probe (Nahp) to detect H2O2 in living cells and bacteria. In addition, based on boronate, Nahp has satisfactory selectivity and sensitivity toward H2O2 (LOD = 0.158 μM). Furthermore, with excellent detection performance to H2O2, Nahp is successfully used for fluorescent bioimaging of H2O2 and measuring H2O2 accumulation in bacteria. Most importantly, the probe was also used to image H2O2 in three Gram-negative bacteria, clearly revealing for the first time significant differences in H2O2 expression levels in live bacteria.

Composition and Antimicrobial Activity of the Essential Oil of a Wild Kiwi

2011 ◽  
Vol 322 ◽  
pp. 160-163
Author(s):  
Yin Lu ◽  
Hong Chen
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Fungal Species ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Leaf Oil ◽  
First Time

A medicinal wild kiwi in China, Actinidia valvata Dunn, has been well known for its activities against leprosy and cancers. The compositions and the antimicrobial activity of its leaf oil were reported for the first time. The oil obtained by hydrodistillation and analyzed by GC and GC-MS, was characterized by the high content of monoterpenes. Linalool (48.14%) is the major component identified, followed by 1,2-dimethyl-lindoline (7.94%), linolenic acid methylester (6.57%) and (E)-phytol (5.29%). The antimicrobial activity of the oil was evaluated against four bacterial and three fungal species. The results showed that it exhibited a mild antibacterial activity against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), a significant activity against Gram-negative bacteria (Escherichia coli), and no activity on Pseudomonas aeruginosa. The test fungi were more sensitive to the oil, with a MIC range of 0.78~1.56 μL/mL than bacteria in the range which were significantly higher from 0.78 to 25.50 μL/mL.

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