scholarly journals Transcriptome Analysis of Aspergillus nidulans Exposed to Camptothecin-Induced DNA Damage

2006 ◽  
Vol 5 (10) ◽  
pp. 1688-1704 ◽  
Author(s):  
Iran Malavazi ◽  
Marcela Savoldi ◽  
Sônia Marli Zingaretti Di Mauro ◽  
Carlos Frederico Martins Menck ◽  
Steven D. Harris ◽  
...  
Keyword(s):  
Dna Damage ◽  
Aspergillus Nidulans ◽  
Mutant Strain ◽  
Deletion Mutant ◽  
Time Course ◽  
Excision Repair ◽  
Wild Type ◽  
Significant Difference ◽  
Mutant Strains ◽  
In The Wild

ABSTRACT We have used an Aspergillus nidulans macroarray carrying sequences of 2,787 genes from this fungus to monitor gene expression of both wild-type and uvsB ATR (the homologue of the ATR gene) deletion mutant strains in a time course exposure to camptothecin (CPT). The results revealed a total of 1,512 and 1,700 genes in the wild-type and uvsB ATR deletion mutant strains that displayed a statistically significant difference at at least one experimental time point. We characterized six genes that have increased mRNA expression in the presence of CPT in the wild-type strain relative to the uvsB ATR mutant strain: fhdA (encoding a forkhead-associated domain protein), tprA (encoding a hypothetical protein that contains a tetratrico peptide repeat), mshA (encoding a MutS homologue involved in mismatch repair), phbA (encoding a prohibitin homologue), uvsC RAD51 (the homologue of the RAD51 gene), and cshA (encoding a homologue of the excision repair protein ERCC-6 [Cockayne's syndrome protein]). The induced transcript levels of these genes in the presence of CPT require uvsB ATR. These genes were deleted, and surprisingly, only the ΔuvsC mutant strain was sensitive to CPT; however, the others displayed sensitivity to a range of DNA-damaging and oxidative stress agents. These results indicate that the selected genes when inactivated display very complex and heterogeneous sensitivity behavior during growth in the presence of agents that directly or indirectly cause DNA damage. Moreover, with the exception of UvsC, deletion of each of these genes partially suppressed the sensitivity of the ΔuvsB strain to menadione and paraquat. Our results provide the first insight into the overall complexity of the response to DNA damage in filamentous fungi and suggest that multiple pathways may act in parallel to mediate DNA repair.

Developmentally related changes in the production and expression of endo-β-1,4-glucanases in Aspergillus nidulans

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 288-292 ◽  
Author(s):  
P. S. Bagga ◽  
S. Sharma ◽  
D. K. Sandhu
Keyword(s):  
Aspergillus Nidulans ◽  
The Other ◽  
Wild Type ◽  
Stages Of Development ◽  
Experimental Conditions ◽  
The Third ◽  
Developmental Mutants ◽  
Mutant Strains ◽  
In The Wild ◽  
Low Levels

The production and electrophoretic expression of endoglucanase(s) were compared in the wild-type and three developmental mutants of Aspergillus nidulans. In the wild type, the production of endoglucanase and its distribution in extracellular and intracellular fractions varied with the age of the culture and the yield was better in stable cultures (production of conidia and cleistothecia) as compared with shake cultures (vegetative hyphae only). Two developmental mutants, aco-T69 and aco-40, which lack the development of conidia and cleistothecia, produced low levels of endoglucanase enzymes as compared with the wild type grown under similar conditions. On the other hand, in aco-90, a mutant capable of producing cleistothecia but no conidia, endoglucanase production was better. The results indicate a correlation between cleistothecial development and endoglucanase level. The electrophoretic studies revealed the presence of three forms of endoglucanase, i.e., EGI, EGII, and EGIII. The first two were detectable in the wild type as well as in mutant strains when grown under various experimental conditions and at all the stages of development. However, the third form could be observed only during cleistothecial development, indicating that this isozyme is developmentally regulated.Key words: endoglucanases, development, Aspergillus nidulans.

scholarly journals Escherichia coli MutM Suppresses Illegitimate Recombination Induced by Oxidative Stress

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 439-446 ◽  
Author(s):  
Masaaki Onda ◽  
Katsuhiro Hanada ◽  
Hirokazu Kawachi ◽  
Hideo Ikeda
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Double Strand Breaks ◽  
Illegitimate Recombination ◽  
Recombination Analysis ◽  
Wild Type ◽  
Strand Breaks ◽  
In The Wild

Abstract DNA damage by oxidative stress is one of the causes of mutagenesis. However, whether or not DNA damage induces illegitimate recombination has not been determined. To study the effect of oxidative stress on illegitimate recombination, we examined the frequency of λbio transducing phage in the presence of hydrogen peroxide and found that this reagent enhances illegitimate recombination. To clarify the types of illegitimate recombination, we examined the effect of mutations in mutM and related genes on the process. The frequency of λbio transducing phage was 5- to 12-fold higher in the mutM mutant than in the wild type, while the frequency in the mutY and mutT mutants was comparable to that of the wild type. Because 7,8-dihydro-8-oxoguanine (8-oxoG) and formamido pyrimidine (Fapy) lesions can be removed from DNA by MutM protein, these lesions are thought to induce illegitimate recombination. Analysis of recombination junctions showed that the recombination at Hotspot I accounts for 22 or 4% of total λbio transducing phages in the wild type or in the mutM mutant, respectively. The preferential increase of recombination at nonhotspot sites with hydrogen peroxide in the mutM mutant was discussed on the basis of a new model, in which 8-oxoG and/or Fapy residues may introduce double-strand breaks into DNA.

scholarly journals Blocks in the pseudouridimycin pathway unlock hidden metabolites in the Streptomyces producer strain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marianna Iorio ◽  
Sahar Davatgarbenam ◽  
Stefania Serina ◽  
Paolo Criscenzo ◽  
Mitja M. Zdouc ◽  
...  
Keyword(s):  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Systematic Investigation ◽  
Biosynthetic Gene ◽  
Wild Type ◽  
Bacterial Rna ◽  
Soil Isolate ◽  
Mutant Strains ◽  
In The Wild ◽  
Polymerase Inhibitor

AbstractWe report a metabolomic analysis of Streptomyces sp. ID38640, a soil isolate that produces the bacterial RNA polymerase inhibitor pseudouridimycin. The analysis was performed on the wild type, on three newly constructed and seven previously reported mutant strains disabled in different genes required for pseudouridimycin biosynthesis. The results indicate that Streptomyces sp. ID38640 is able to produce, in addition to lydicamycins and deferroxiamines, as previously reported, also the lassopeptide ulleungdin, the non-ribosomal peptide antipain and the osmoprotectant ectoine. The corresponding biosynthetic gene clusters were readily identified in the strain genome. We also detected the known compound pyridindolol, for which we propose a previously unreported biosynthetic gene cluster, as well as three families of unknown metabolites. Remarkably, the levels of most metabolites varied strongly in the different mutant strains, an observation that enabled detection of metabolites unnoticed in the wild type. Systematic investigation of the accumulated metabolites in the ten different pum mutants identified shed further light on pseudouridimycin biosynthesis. We also show that several Streptomyces strains, able to produce pseudouridimycin, have distinct genetic relationship and metabolic profile with ID38640.

scholarly journals N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways

2021 ◽  
Vol 22 (14) ◽  
pp. 7565
Author(s):  
Kyungho Woo ◽  
Dong Ho Kim ◽  
Man Hwan Oh ◽  
Ho Sung Park ◽  
Chul Hee Choi
Keyword(s):  
Bone Marrow ◽  
Quorum Sensing ◽  
Deletion Mutant ◽  
Transmembrane Protein ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Host Responses ◽  
Wild Type ◽  
Mutant Strains

Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.

scholarly journals RpoS-Dependent Stress Response and Exoenzyme Production in Vibrio vulnificus

2003 ◽  
Vol 69 (10) ◽  
pp. 6114-6120 ◽  
Author(s):  
A. Hülsmann ◽  
T. M. Rosche ◽  
I.-S. Kong ◽  
H. M. Hassan ◽  
D. M. Beam ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Stress Response ◽  
Mutant Strain ◽  
Environmental Changes ◽  
Vibrio Vulnificus ◽  
High Sensitivity ◽  
Striking Difference ◽  
Wild Type ◽  
Hydrolytic Activities ◽  
In The Wild

ABSTRACT Vibrio vulnificus is an estuarine bacterium capable of causing rapidly fatal infections through both ingestion and wound infection. Like other opportunistic pathogens, V. vulnificus must adapt to potentially stressful environmental changes while living freely in seawater, upon colonization of the oyster gut, and upon infection of such diverse hosts as humans and eels. In order to begin to understand the ability of V. vulnificus to respond to such stresses, we examined the role of the alternate sigma factor RpoS, which is important in stress response and virulence in many pathogens. An rpoS mutant of V. vulnificus strain C7184o was constructed by homologous recombination. The mutant strain exhibited a decreased ability to survive diverse environmental stresses, including exposure to hydrogen peroxide, hyperosmolarity, and acidic conditions. The most striking difference was a high sensitivity of the mutant to hydrogen peroxide. Albuminase, caseinase, and elastase activity were detected in the wild type but not in the mutant strain, and an additional two hydrolytic activities (collagenase and gelatinase) were reduced in the mutant strain compared to the wild type. Additionally, the motility of the rpoS mutant was severely diminished. Overall, these studies suggest that rpoS in V. vulnificus is important for adaptation to environmental changes and may have a role in virulence.

scholarly journals Aspergillus nidulans Protein O-Mannosyltransferases Play Roles in Cell Wall Integrity and Developmental Patterning

2009 ◽  
Vol 8 (10) ◽  
pp. 1475-1485 ◽  
Author(s):  
Thanyanuch Kriangkripipat ◽  
Michelle Momany
Keyword(s):  
Cell Wall ◽  
Aspergillus Nidulans ◽  
Double Mutant ◽  
Elevated Temperatures ◽  
Cell Wall Integrity ◽  
Wild Type ◽  
Spatial Cues ◽  
Developmental Patterning ◽  
In The Wild ◽  
Increased Sensitivity

ABSTRACT Protein O-mannosyltransferases (Pmts) initiate O-mannosyl glycan biosynthesis from Ser and Thr residues of target proteins. Fungal Pmts are divided into three subfamilies, Pmt1, -2, and -4. Aspergillus nidulans possesses a single representative of each Pmt subfamily, pmtA (subfamily 2), pmtB (subfamily 1), and pmtC (subfamily 4). In this work, we show that single Δpmt mutants are viable and have unique phenotypes and that the ΔpmtA ΔpmtB double mutant is the only viable double mutant. This makes A. nidulans the first fungus in which all members of individual Pmt subfamilies can be deleted without loss of viability. At elevated temperatures, all A. nidulans Δpmt mutants show cell wall-associated defects and increased sensitivity to cell wall-perturbing agents. The Δpmt mutants also show defects in developmental patterning. Germ tube emergence is early in ΔpmtA and more frequent in ΔpmtC mutants than in the wild type. In ΔpmtB mutants, intrahyphal hyphae develop. All Δpmt mutants show distinct conidiophore defects. The ΔpmtA strain has swollen vesicles and conidiogenous cells, the ΔpmtB strain has swollen conidiophore stalks, and the ΔpmtC strain has dramatically elongated conidiophore stalks. We also show that AN5660, an ortholog of Saccharomyces cerevisiae Wsc1p, is modified by PmtA and PmtC. The Δpmt phenotypes at elevated temperatures, increased sensitivity to cell wall-perturbing agents and restoration to wild-type growth with osmoticum suggest that A. nidulans Pmts modify proteins in the cell wall integrity pathway. The altered developmental patterns in Δpmt mutants suggest that A. nidulans Pmts modify proteins that serve as spatial cues.

scholarly journals Activation of 2,4-Diaminoquinazoline in Mycobacterium tuberculosis by Rv3161c, a Putative Dioxygenase

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Eduard Melief ◽  
Shilah A. Bonnett ◽  
Edison S. Zuniga ◽  
Tanya Parish
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Type A ◽  
Wild Type ◽  
Metabolite Analysis ◽  
Content Type ◽  
Data Support ◽  
In The Wild

ABSTRACT The diaminoquinazoline series has good potency against Mycobacterium tuberculosis. Resistant isolates have mutations in Rv3161c, a putative dioxygenase. We carried out metabolite analysis on a wild-type strain and an Rv3161c mutant strain after exposure to a diaminoquinazoline. The parental compound was found in intracellular extracts from the mutant but not the wild type. A metabolite consistent with a monohydroxylated form was identified in the wild type. These data support the hypothesis that Rv3161c metabolizes diaminoquinazolines in M. tuberculosis.

Sensitivity of normal and mutant strains of Escherichia coli to actinomycin-D

1972 ◽  
Vol 18 (6) ◽  
pp. 909-915 ◽  
Author(s):  
A. P. Singh ◽  
K.-J. Cheng ◽  
J. W. Costerton ◽  
E. S. Idziak ◽  
J. M. Ingram
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Wild Type Strain ◽  
Actinomycin D ◽  
Cytoplasmic Membrane ◽  
Cell Envelope ◽  
Coli Strain ◽  
Wild Type ◽  
Mutant Strains ◽  
In The Wild

The site of the cell barrier to actinomycin-D uptake was studied using a wild-type Escherichia coli strain P and its cell envelope-defective filamentous mutants, strains 6γ and 12γ, both of which 'leak' β-galactosidase and alkaline phosphatase into the medium during growth indicating both membrane and cell-wall defects. Actinomycin-D entered the cells of these two mutant strains as evidenced by the inhibition of both 14C-uracil incorporation and synthesis of the induced β-galactosidase system. Under similar conditions, no inhibition occurred in the wild-type strain and its sucrose-lysozyme prepared spheroplasts. Actinomycin-D did, however, inhibit the above-mentioned systems in the wild-type sucrose-lysozyme spheroplasts prepared in the presence of 2 mM EDTA. The experimental data indicate that although the cell wall may act as a primary barrier or sieve to actinomycin-D, the cytoplasmic membrane should be considered the final and determinative barrier to this antibiotic.

scholarly journals Autoproteolysis of YscU of Yersinia pseudotuberculosis Is Important for Regulation of Expression and Secretion of Yop Proteins

2009 ◽  
Vol 191 (13) ◽  
pp. 4259-4267 ◽  
Author(s):  
Ann-Catrin Björnfot ◽  
Moa Lavander ◽  
Åke Forsberg ◽  
Hans Wolf-Watz
Keyword(s):  
Type Iii Secretion ◽  
Calcium Concentration ◽  
Wild Type Strain ◽  
Yersinia Pseudotuberculosis ◽  
Secretion System ◽  
Wild Type ◽  
Regulation Of Expression ◽  
Significant Difference ◽  
In The Wild ◽  
Needle Protein

ABSTRACT YscU of Yersinia can be autoproteolysed to generate a 10-kDa C-terminal polypeptide designated YscUCC. Autoproteolysis occurs at the conserved N↓PTH motif of YscU. The specific in-cis-generated point mutants N263A and P264A were found to be defective in proteolysis. Both mutants expressed and secreted Yop proteins (Yops) in calcium-containing medium (+Ca2+ conditions) and calcium-depleted medium (−Ca2+ conditions). The level of Yop and LcrV secretion by the N263A mutant was about 20% that of the wild-type strain, but there was no significant difference in the ratio of the different secreted Yops, including LcrV. The N263A mutant secreted LcrQ regardless of the calcium concentration in the medium, corroborating the observation that Yops were expressed and secreted in Ca2+-containing medium by the mutant. YscF, the type III secretion system (T3SS) needle protein, was secreted at elevated levels by the mutant compared to the wild type when bacteria were grown under +Ca2+ conditions. YscF secretion was induced in the mutant, as well as in the wild type, when the bacteria were incubated under −Ca2+ conditions, although the mutant secreted smaller amounts of YscF. The N263A mutant was cytotoxic for HeLa cells, demonstrating that the T3SS-mediated delivery of effectors was functional. We suggest that YscU blocks Yop release and that autoproteolysis is required to relieve this block.

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