Studies on a new antibiotic M-92 produced by Micromonospora. IV. Bactericidal action of the component VA-2.

Tani, Kato; Yamaguchi, Toutaro

doi:10.7164/antibiotics.36.289

Cited by 3 publications

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“…10,11 MMC produces intrastrand and interstrand cross-links in addition to monofunctional alkyl lesions in DNA 12 and at supra-inhibitory concentrations modulates the transcriptional expression of a large number of S. aureus genes. 13 Although the SOS response elicited by subinhibitory concentrations of ELB-21 appears to be more restricted than that associated with MMC, both induce prophage into the lytic cycle with concomitant release of phage particles.…”

Section: Introductionmentioning

confidence: 99%

The minor groove-binding agent ELB-21 forms multiple interstrand and intrastrand covalent cross-links with duplex DNA and displays potent bactericidal activity against methicillin-resistant Staphylococcus aureus

Rosado¹,

Rahman²,

Feuerbaum³

et al. 2011

Journal of Antimicrobial Chemotherapy

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ObjectivesThe antistaphylococcal pyrrolobenzodiazepine dimer ELB-21 forms multiple adducts with duplex DNA through covalent interactions with appropriately spaced guanine residues; it is now known to form interstrand and intrastrand adducts with oligonucleotide sequences of variable length. We determined the DNA sequence preferences of ELB-21 in relation to its capacity to exert a bactericidal effect by damaging DNA.MethodsFormation of adducts by ELB-21 and 12- to 14-mer DNA duplexes was investigated using ion-pair reversed phase liquid chromatography and mass spectrometry. Drug-induced changes in gene expression were measured in prophage-free Staphylococcus aureus RN4220 by microarray analysis.ResultsELB-21 preferentially formed intrastrand adducts with guanines separated by three nucleotide base pairs. Interstrand and intrastrand adducts were formed with duplexes both longer and shorter than the preferred target sequences. ELB-21 elicited rapid bactericidal effects against prophage-carrying and prophage-free S. aureus strains; cell lysis occurred following activation and release of resident prophages. Killing appeared to be due to irreparable damage to bacterial DNA and susceptibility to ELB-21 was governed by the capacity of staphylococci to repair DNA lesions through induction of the SOS DNA damage response mediated by the RecA-LexA pathway.ConclusionsThe data support the contention that ELB-21 arrests DNA replication, eliciting formation of ssDNA-RecA filaments that inactivate LexA, the SOS repressor, and phage repressors such as Cl, resulting in activation of the DNA damage response and de-repression of resident prophages. Above the MIC threshold, DNA repair is ineffective.

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Section: Introductionmentioning

confidence: 99%

The minor groove-binding agent ELB-21 forms multiple interstrand and intrastrand covalent cross-links with duplex DNA and displays potent bactericidal activity against methicillin-resistant Staphylococcus aureus

Rosado¹,

Rahman²,

Feuerbaum³

et al. 2011

Journal of Antimicrobial Chemotherapy

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Green and Sustainable Antibiofouling Coatings: A Review

Amir

Yusof

Ismail

2021

IOP Conf. Ser.: Earth Environ. Sci.

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Marine biofouling, the unwanted accumulation of living organisms on man-made structures is worsening every year. Biofouling in marine environment usually occurs in any wetted surface, submerged for a period of time in the seawater. This phenomenon happens in few stages started with conditioning and followed by attachment and colonization. Marine biofouling is a highly cost problem which requires unnecessary waste of financial source especially in fuel consumption and production time as well as safety problems. The currently used antibiofouling paint is reported to be highly toxic and threatening the marine organisms. The most commonly used antibiofouling agents are biocide-based such as the tributyl-n-tin (TBT), Sea Nine 211, Irgarol 1051, Diuron and the copper-based. The well-developed coating companies such as Hempel USA, SeaCoat Technology, Nippon Paint and many more has started their involvement in making the earths greener by introducing the non-biocide coating that is claimed to be as good as the biocide based antibiofouling coatings. Although the paints did not clearly state the antibiofouling agents used to replace biocide, the paints introduced are however, still has its own drawbacks. The secondary metabolites extractedfrom natural products as a defence mechanism is a potential green antibiofouling agent. Apart of its lower toxicity, natural products are also biodegradable. Further study on development of sustainable antibiofouling coating is crucial. This paper intended to review available green and sustainable antifouling compound used as paint or coating. The effectiveness and toxicity of the antifoulant will be critically reviewed.

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Studies on a new antibiotic M-92 produced by Micromonospora. II. Isolation and physicochemical properties of M-92 and its components.

Tani

Takaishi

1982

J. Antibiot.

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A new antibiotic complex, M-92 was isolated from the whole fermentation broth of Micromonospora verruculosa MCRL 0404. The whole broth was mixed with talc and filtered. The filter cake thus obtained was extracted with acidic methanol to give a crude powder of M-92 complex, which was then separated into A (acidic) and N (neutral or weakly acidic) groups. The A group components are soluble in alkaline water (pH 8.5), while the N group components are not. These components were further separated into six major components designated VA-2, BA-4, BA-5, BN-1, BN-2 and BN-3 by silica gel column chromatography.Components with the letter "V" are reddish violet and those with "B" are blue.The IR and UV spectra of these components suggest that their chromophores may be the same or very closely related to one another.The molecular formula of BN-3 was determined to be C28H23NO8 by mass spectrometry.The results of various spectroscopies on BN-3 suggest that M-92 components consisted of chromophores in which juglone (5-hydroxynaphthoquinone) is conjugated with naphthazarin (5,8-dihydroxynaphthoquinone).In screening for new antibiotics produced by Micromonospora, we found that a new strain for which the name Micronionospora verruculosa sp. nov.1) was proposed, produced a new antibiotic complex named M-92 which was exceedingly active against some Gram-positive and Gram-negative bacteria.M-92 complex was extracted with acidic methanol from the mycelial cake. Crude complex was then separated into six major components designated VA-2, BA-4, BA-5, BN-1, BN-2 and BN-3 by silica gel H column chromatography. They were acidic or neutral in nature and blue or violet in color. This paper deals with the isolation and purification of the M-92 components and their physicochemical properties. Biological properties of these components will be reported in the succeeding paper2). The structural elucidation of these components is now under way. Isolation and PurificationIsolation of a crude powder of the M-92 complex was achieved as shown in Chart 1. Thus, 24 g of a crude powder of the M-92 complex was obtained from 1,000 liters of fermentation broth.According to the procedures shown in Chart 2, the chloroform solution of the M-92 complex was separated into A group (acidic substances) which is soluble in alkaline water (Na2CO3, pH 8.5) and N group (weakly acidic or neutral substances) which is insoluble. The A group components in the chloroform layer were washed with water and then evaporated to dryness in vacuo. Thus, 6.5 g of a crude powder of the A group components and 10.4 g of a crude powder of the N group components were obtained from 20 g of crude M-92 complex.The isolation and purification of the A group components were carried out by silica gel H [Merck, impregnated with 0.5 M Mcllvain buffer (pH 5)] column chromatography as shown in Chart 3. Then,

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Studies on a new antibiotic M-92 produced by Micromonospora. IV. Bactericidal action of the component VA-2.

Cited by 3 publications

References 0 publications

The minor groove-binding agent ELB-21 forms multiple interstrand and intrastrand covalent cross-links with duplex DNA and displays potent bactericidal activity against methicillin-resistant Staphylococcus aureus

The minor groove-binding agent ELB-21 forms multiple interstrand and intrastrand covalent cross-links with duplex DNA and displays potent bactericidal activity against methicillin-resistant Staphylococcus aureus

Green and Sustainable Antibiofouling Coatings: A Review

Studies on a new antibiotic M-92 produced by Micromonospora. II. Isolation and physicochemical properties of M-92 and its components.

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