scholarly journals Soluble cytochromes c of a KCN-resistant mutant of an obligate methylotroph, Methylomonas sp.

1986 ◽  
Vol 50 (10) ◽  
pp. 2545-2552 ◽  
Author(s):  
Yoshiki TANI ◽  
Byung Dae YOON ◽  
Hideaki YAMADA
Keyword(s):  
Resistant Mutant ◽  
Obligate Methylotroph ◽  
Cytochromes C

Soluble Cytochromescof a KCN-resistant Mutant of an Obligate Methylotroph,Methylomonassp.

1986 ◽  
Vol 50 (10) ◽  
pp. 2545-2552
Author(s):  
Yoshiki Tani ◽  
Byung Dae Yoon ◽  
Hideaki Yamada
Keyword(s):  
Resistant Mutant ◽  
Obligate Methylotroph

scholarly journals The electron-transport chains of the obligate methylotroph Methylophilus methylotrophus

1980 ◽  
Vol 192 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Andrew R. Cross ◽  
Christopher Anthony
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Redox Potentials ◽  
Obligate Methylotroph ◽  
Methylophilus Methylotrophus ◽  
Cytochrome O ◽  
Cytochromes C ◽  
Band Absorption ◽  
Membrane Bound ◽  
Α Band

The cytochrome complement of Methylophilus methylotrophus and its respiratory properties were determined during batch culture and in continuous culture under conditions of methanol-, nitrogen- and O2-limitation. About 35% of the cytochrome c produced by the bacteria was released into the growth medium, and of the remaining cytochrome c about half was membrane-bound and half was soluble. Two cytochromes c were always present on membranes (redox potentials 375mV and 310mV), and these probably correspond to the soluble cytochromes c described previously [Cross & Anthony (1980) Biochem. J.192, 421–427]. A third minor component of cytochrome c (midpoint potential 356mV) was only detected on membranes of methanol-limited bacteria. M. methylotrophus always contained two membrane-bound cytochromes b with α-band absorption maxima of about 556 and 563nm (measured at room temperature) and midpoint potentials of 110 and 60mV respectively. There appeared to be relatively more of the cytochrome b563 in methanol-limited bacteria. A third b-type cytochrome with an α-band absorption maximum at 558 (at 77K) reacted with CO and had a high midpoint redox potential (260mV); it is thus a potential oxidase and hence is called cytochrome o. The roles of these cytochromes in electron transport were confirmed by investigating the patterns of respiratory inhibition. It is proposed that two cytochromes are physiological oxidases: cytochrome a+a3, which is present only in methanol-limited conditions, and the cytochrome o, which is induced 10-fold in conditions of methanol excess. Schemes for electron transport from methanol and NAD(P)H to O2 in M. methylotrophus under various limitations are proposed. Spectra and potentiometric titrations of cytochromes in whole cells and membranes of M. methylotrophus grown under various nutrient limitations have been deposited as Supplementary Publication SUP 50111 (10 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

scholarly journals The purification and properties of the soluble cytochromes c of the obligate methylotroph Methylophilus methylotrophus

1980 ◽  
Vol 192 (2) ◽  
pp. 421-427 ◽  
Author(s):  
A R Cross ◽  
C Anthony
Keyword(s):  
Molecular Weight ◽  
Isoelectric Point ◽  
Low Molecular Weight ◽  
Redox Potentials ◽  
Obligate Methylotroph ◽  
Methylophilus Methylotrophus ◽  
Midpoint Potential ◽  
Purification And Properties ◽  
Cytochromes C ◽  
Cytochrome Cl

The obligate methylotroph Methylophilus methylotrophus contains three distinct soluble cytochromes c. The major cytochromes, cytochrome cH (about 50% of the total) and cytochrome cL (about 42%), were similar in most respects to the cytochromes cH and cL of the facultative methylotroph Pseudomonas AM1 [O'Keeffe & Anthony (1980) Biochem. J. 192, 411-419]. Cytochrome cH had a high isoelectric point, a midpoint redox potential at pH 7.0 of 373 mV and a low molecular weight (8500). The cytochrome cL had a low isoelectric point, a midpoint potential of 310 mV and a molecular weight of 21,000. The third cytochrome, cytochrome cLM, was clearly distinct from cytochromes cH and cL. Like the cytochrome cL of Pseudomonas AM1, the cytochrome cL of M. methylotrophus had the lowest midpoint potential, it reacted most rapidly with methanol dehydrogenase and it combined to the greatest extent with CO. Cytochromes cH and L of M. methylotrophus differed from those from Pseudomonas AM1 in having unusually high midpoint redox potentials for non-photosynthetic bacteria and in exhibiting a split alpha-band at low temperatures.

Comparative Proteomic and Transcriptome Analysis of Nitron-Oligomycin Resistant Mutant Streptomyces fradiae-nitR+bld Strain

2020 ◽  
Vol 56 (9) ◽  
pp. 1151-1154
Author(s):  
O. B. Bekker ◽  
A. A. Vatlin ◽  
D. A. Mavletova ◽  
L. N. Lysenkova ◽  
A. E. Shchekotikhin ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Resistant Mutant ◽  
Streptomyces Fradiae

scholarly journals Moxifloxacin Activates the SOS Response in Mycobacterium tuberculosis in a Dose- and Time-Dependent Manner

2021 ◽  
Vol 9 (2) ◽  
pp. 255
Author(s):  
Angelo Iacobino ◽  
Giovanni Piccaro ◽  
Manuela Pardini ◽  
Lanfranco Fattorini ◽  
Federico Giannoni
Keyword(s):  
Gene Expression ◽  
Mycobacterium Tuberculosis ◽  
Physiological State ◽  
Transcriptional Response ◽  
Sos Response ◽  
Resistant Mutant ◽  
Time Dependent ◽  
Dependent Manner ◽  
Gyra Gene ◽  
Drug Concentrations

Previous studies on Escherichia coli demonstrated that sub-minimum inhibitory concentration (MIC) of fluoroquinolones induced the SOS response, increasing drug tolerance. We characterized the transcriptional response to moxifloxacin in Mycobacterium tuberculosis. Reference strain H37Rv was treated with moxifloxacin and gene expression studied by qRT-PCR. Five SOS regulon genes, recA, lexA, dnaE2, Rv3074 and Rv3776, were induced in a dose- and time-dependent manner. A range of moxifloxacin concentrations induced recA, with a peak observed at 2 × MIC (0.25 μg/mL) after 16 h. Another seven SOS responses and three DNA repair genes were significantly induced by moxifloxacin. Induction of recA by moxifloxacin was higher in log-phase than in early- and stationary-phase cells, and absent in dormant bacilli. Furthermore, in an H37Rv fluoroquinolone-resistant mutant carrying the D94G mutation in the gyrA gene, the SOS response was induced at drug concentrations higher than the mutant MIC value. The 2 × MIC of moxifloxacin determined no significant changes in gene expression in a panel of 32 genes, except for up-regulation of the relK toxin and of Rv3290c and Rv2517c, two persistence-related genes. Overall, our data show that activation of the SOS response by moxifloxacin, a likely link to increased mutation rate and persister formation, is time, dose, physiological state and, possibly, MIC dependent.

scholarly journals Bacterial Resistance to Antisense Peptide Phosphorodiamidate Morpholino Oligomers

2012 ◽  
Vol 56 (12) ◽  
pp. 6147-6153 ◽  
Author(s):  
Susan E. Puckett ◽  
Kaleb A. Reese ◽  
Georgi M. Mitev ◽  
Valerie Mullen ◽  
Rudd C. Johnson ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Acyl Carrier Protein ◽  
Essential Gene ◽  
Resistant Mutant ◽  
Resistant Isolate ◽  
Carrier Protein ◽  
Bacterial Gene ◽  
Content Type ◽  
Bacterial Gene Expression ◽  
Phosphorodiamidate Morpholino Oligomers

ABSTRACTPeptide phosphorodiamidate morpholino oligomers (PPMOs) are synthetic DNA mimics that bind cRNA and inhibit bacterial gene expression. The PPMO (RFF)3RXB-AcpP (where R is arginine, F, phenylalanine, X is 6-aminohexanoic acid, B is β-alanine, and AcpP is acyl carrier protein) is complementary to 11 bases of the essential geneacpP(which encodes acyl carrier protein). The MIC of (RFF)3RXB-AcpP was 2.5 μM (14 μg/ml) inEscherichia coliW3110. The rate of spontaneous resistance ofE. colito (RFF)3RXB-AcpP was 4 × 10−7mutations/cell division. A spontaneous (RFF)3RXB-AcpP-resistant mutant (PR200.1) was isolated. The MIC of (RFF)3RXB-AcpP was 40 μM (224 μg/ml) for PR200.1. The MICs of standard antibiotics for PR200.1 and W3110 were identical. The sequence ofacpPwas identical in PR200.1 and W3110. PR200.1 was also resistant to other PPMOs conjugated to (RFF)3RXB or peptides with a similar composition or pattern of cationic and nonpolar residues. Genomic sequencing of PR200.1 identified a mutation insbmA, which encodes an active transport protein. In separate experiments, a (RFF)3RXB-AcpP-resistant isolate (RR3) was selected from a transposome library, and the insertion was mapped tosbmA. Genetic complementation of PR200.1 or RR3 withsbmArestored susceptibility to (RFF)3RXB-AcpP. Deletion ofsbmAcaused resistance to (RFF)3RXB-AcpP. We conclude that resistance to (RFF)3RXB-AcpP was linked to the peptide and not the phosphorodiamidate morpholino oligomer, dependent on the composition or repeating pattern of amino acids, and caused by mutations insbmA. The data further suggest that (RFF)3R-XB PPMOs may be transported across the plasma membrane by SbmA.

scholarly journals CHROMOSOMAL BASIS OF THE MEROZYGOSITY IN A PARTIALLY DIPLOID MUTANT OF PNEUMOCOCCUS

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 667-678
Author(s):  
Mary Lee S Ledbetter ◽  
Rollin D Hotchkiss
Keyword(s):  
High Efficiency ◽  
Point Mutations ◽  
Resistant Mutant ◽  
Chromosomal Marker ◽  
Structural Abnormality ◽  
C Cells ◽  
Wild Type ◽  
Chromosomal Locus ◽  
Low Efficiency ◽  
Derivatives Of

ABSTRACT A sulfonamide-resistant mutant of pneumococcus, sulr-c, displays a genetic instability, regularly segregating to wild type. DNA extracts of derivatives of the strain possess transforming activities for both the mutant and wild-type alleles, establishing that the strain is a partial diploid. The linkage of sulr-c to strr-61, a stable chromosomal marker, was established, thus defining a chromosomal locus for sulr-c. DNA isolated from sulr-c cells transforms two mutant recipient strains at the same low efficiency as it does a wild-type recipient, although the mutant property of these strains makes them capable of integrating classical "low-efficiency" donor markers equally as efficiently as "high efficiency" markers. Hence sulr-c must have a different basis for its low efficiency than do classical low efficiency point mutations. We suggest that the DNA in the region of the sulr-c mutation has a structural abnormality which leads both to its frequent segregation during growth and its difficulty in efficiently mediating genetic transformation.

Sign in / Sign up

Export Citation Format

Share Document