scholarly journals Homologous recombination as the main mechanism for DNA integration and cause of rearrangements in the filamentous ascomycete Ashbya gossypii.

Genetics ◽  
1995 ◽  
Vol 140 (3) ◽  
pp. 973-987 ◽  
Author(s):  
S Steiner ◽  
J Wendland ◽  
M C Wright ◽  
P Philippsen
Keyword(s):  
Resistance Gene ◽  
Gene Replacement ◽  
Phytopathogenic Fungus ◽  
Ashbya Gossypii ◽  
Aminoglycoside Resistance ◽  
Genetic Changes ◽  
Apparent Lack ◽  
Dna Integration ◽  
Filamentous Ascomycete ◽  
One Step

Abstract A slow and a fast growth phenotype were observed after transformation of the phytopathogenic fungus Ashbya gossypii using a plasmid carrying homologous DNA and as selectable marker the Tn903 aminoglycoside resistance gene expressed from a strong A. gossypii promoter. Transformations with circular plasmids yielded slowly and irregularly growing geneticin-resistant mycelia in which 1% of nuclei contained plasmid sequences. Occasionally, fast growing sectors appeared which were shown to be initiated by homologous integration of the transforming DNA. Transformants obtained with plasmids linearized within the homology region immediately exhibited fast radial growth. In all 28 transformants analyzed plasmid DNA was integrated homologously. Such apparent lack of nonhomologous recombination has so far not been observed in filamentous ascomycetes. In 14 transformants two to four tandemly integrated plasmid copies were found. They underwent several types of genetic changes, mainly in the older mycelium: excision of whole plasmid copies and rearrangements within the integrated DNA (inversions and deletions). These internal rearrangements involved 360-bp inverted repeats, remnants of IS-elements flanking the resistance gene, and 156-bp direct repeats, originating from the strong A. gossypii promoter. Improved vectors lacking sequence repetitions were constructed and used for stable one-step gene replacement in A. gossypii.

Methodological improvements in the expression of foreign genes and in gene replacement in the phytopathogenic fungus Botrytis cinerea

2007 ◽  
Vol 8 (6) ◽  
pp. 811-816 ◽  
Author(s):  
JUDITH NODA ◽  
NÉLIDA BRITO ◽  
JOSÉ J. ESPINO ◽  
CELEDONIO GONZÁLEZ
Keyword(s):  
Botrytis Cinerea ◽  
Gene Replacement ◽  
Phytopathogenic Fungus ◽  
Foreign Genes

High frequency one-step gene replacement in Trichoderma reesei. II. Effects of deletions of individual cellulase genes

1993 ◽  
Vol 241-241 (5-6) ◽  
pp. 523-530 ◽  
Author(s):  
Pirkko L. Suominen ◽  
Arja L. Mäntylä ◽  
Taina Karhunen ◽  
Satu Hakola ◽  
Helena Nevalainen
Keyword(s):  
Trichoderma Reesei ◽  
High Frequency ◽  
Gene Replacement ◽  
One Step

scholarly journals Co-occurrence of aminoglycoside resistance gene armA in non-Typhi Salmonella isolates producing CTX-M-15 in Algeria

2011 ◽  
Vol 66 (9) ◽  
pp. 2180-2181 ◽  
Author(s):  
N. Bouzidi ◽  
L. Aoun ◽  
M. Dekhil ◽  
S. A. Granier ◽  
L. Poirel ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Aminoglycoside Resistance

scholarly journals Characterization of IS18, an Element Capable of Activating the Silent aac(6′)-Ij Gene ofAcinetobacter sp. 13 Strain BM2716 by Transposition

1998 ◽  
Vol 42 (10) ◽  
pp. 2759-2761 ◽  
Author(s):  
Eric Rudant ◽  
Patrice Courvalin ◽  
Thierry Lambert
Keyword(s):  
Resistance Gene ◽  
Insertion Sequence ◽  
Resistant Mutant ◽  
Open Reading Frame ◽  
Inverted Repeats ◽  
Aminoglycoside Resistance ◽  
Reading Frame ◽  
Terminal Inverted Repeats ◽  
Hybrid Promoter

ABSTRACT Insertion sequence IS18 was detected by analysis of the spontaneous aminoglycoside resistant mutant Acinetobactersp. 13 strain BM2716-1. Insertion of the element upstream from the silent acetyltransferase gene aac(6′)-Ij created a hybrid promoter that putatively accounts for the expression of the aminoglycoside resistance gene. The 1,074-bp IS18 element contained partially matched (20 out of 26 bases) terminal inverted repeats, one of which overlapped the 3′ end of a 935-bp open reading frame potentially encoding a protein related to the transposases of the IS30 family. IS18 was found in 6 out of 29 strains of Acinetobacter sp. 13 but not in 10 strains each of A. baumannii and A. haemolyticus.

scholarly journals Class 1 Integron-Associated Tobramycin-Gentamicin Resistance in Campylobacter jejuni Isolated from the Broiler Chicken House Environment

2002 ◽  
Vol 46 (11) ◽  
pp. 3660-3664 ◽  
Author(s):  
Margie D. Lee ◽  
Susan Sanchez ◽  
Martha Zimmer ◽  
Umelaalim Idris ◽  
Mark E. Berrang ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Campylobacter Jejuni ◽  
Broiler Chicken ◽  
Aminoglycoside Resistance ◽  
Class 1 Integron ◽  
Integrase Gene ◽  
Conserved Sequence ◽  
Chicken House ◽  
Class 1 ◽  
Gentamicin Resistance

ABSTRACT Using PCR, we screened 105 isolates of poultry-associated Campylobacter jejuni for the presence of class 1 integrons. Of those isolates, 21% (22 of 105) possessed the integrase gene, but only 5 isolates produced an amplicon in a 5′-3′ conserved sequence PCR directed toward amplification of the resistance cassettes. DNA sequencing demonstrated that all five isolates possessed the aminoglycoside resistance gene, aacA4.

scholarly journals Regulation of exit from mitosis in multinucleate Ashbya gossypii cells relies on a minimal network of genes

2011 ◽  
Vol 22 (17) ◽  
pp. 3081-3093 ◽  
Author(s):  
Mark R. Finlayson ◽  
A. Katrin Helfer-Hungerbühler ◽  
Peter Philippsen
Keyword(s):  
Regulatory Networks ◽  
Temporal Constraints ◽  
Ashbya Gossypii ◽  
Metaphase Arrest ◽  
Minimal Network ◽  
Filamentous Ascomycete ◽  
Low Degree ◽  
Mitotic Exit Network ◽  
Early Anaphase ◽  
Core Components

In Saccharomyces cerevisiae, mitosis is coupled to cell division by the action of the Cdc fourteen early anaphase release (FEAR) and mitotic exit network (MEN) regulatory networks, which mediate exit from mitosis by activation of the phosphatase Cdc14. The closely related filamentous ascomycete Ashbya gossypii provides a unique cellular setting to study the evolution of these networks. Within its multinucleate hyphae, nuclei are free to divide without the spatial and temporal constraints described for budding yeast. To investigate how this highly conserved system has adapted to these circumstances, we constructed a series of mutants lacking homologues of core components of MEN and FEAR and monitored phenomena such as progression through mitosis and Cdc14 activation. MEN homologues in A. gossypii were shown to have diverged from their anticipated role in Cdc14 release and exit from mitosis. We observed defects in septation, as well as a partial metaphase arrest, in Agtem1Δ, Agcdc15Δ, Agdbf2/dbf20Δ, and Agmob1Δ. A. gossypii homologues of the FEAR network, on the other hand, have a conserved and more pronounced role in regulation of the M/G1 transition. Agcdc55Δ mutants are unable to sequester AgCdc14 throughout interphase. We propose a reduced model of the networks described in yeast, with a low degree of functional redundancy, convenient for further investigations into these networks.

scholarly journals Identification of Pathogenesis-Associated Genes by T-DNA–Mediated Insertional Mutagenesis in Botrytis cinerea: A Type 2A Phosphoprotein Phosphatase and an SPT3 Transcription Factor Have Significant Impact on Virulence

2012 ◽  
Vol 25 (4) ◽  
pp. 481-495 ◽  
Author(s):  
S. Giesbert ◽  
J. Schumacher ◽  
V. Kupas ◽  
J. Espino ◽  
N. Segmüller ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Protein Phosphatase ◽  
Insertional Mutagenesis ◽  
Single Copy ◽  
Gene Replacement ◽  
Gray Mold ◽  
Dna Integration ◽  
Bean Plants ◽  
Mold Fungus ◽  
Border Sequence

Agrobacterium tumefaciens–mediated transformation (ATMT) was used to generate an insertional mutant library of the gray mold fungus Botrytis cinerea. From a total of 2,367 transformants, 68 mutants showing significant reduction in virulence on tomato and bean plants were analyzed in detail. As reported for other fungal ATMT libraries, integrations were mostly single copy, occurred preferentially in noncoding (regulatory) regions, and were frequently accompanied by small deletions of the target sequences and loss of parts of the border sequence. Two T-DNA integration events that were found to be linked to virulence were characterized in more detail: a catalytic subunit of a PP2A serine/threonine protein phosphatase (BcPP2Ac) and the SPT3 subunit of a Spt-Ada-Gcn5-acetyltransferase (SAGA-like) transcriptional regulator complex. Gene replacement and silencing approaches revealed that both Bcpp2Ac and SPT3 are crucial for virulence, growth, and differentiation as well as for resistance to H2O2 in B. cinerea.

scholarly journals Triclosan-Induced Aminoglycoside-Tolerant Listeria monocytogenes Isolates Can Appear as Small-Colony Variants

2014 ◽  
Vol 58 (6) ◽  
pp. 3124-3132 ◽  
Author(s):  
Vicky G. Kastbjerg ◽  
Line Hein-Kristensen ◽  
Lone Gram
Keyword(s):  
Listeria Monocytogenes ◽  
Active Transport ◽  
Aminoglycoside Resistance ◽  
Carbohydrate Utilization ◽  
Genetic Changes ◽  
Content Type ◽  
Persistent Infections ◽  
Food Borne ◽  
Gentamicin Resistance ◽  
Small Colony

ABSTRACTExposure of the human food-borne pathogenListeria monocytogenesto sublethal concentrations of triclosan can cause resistance to several aminoglycosides. Aminoglycoside-resistant isolates exhibit two colony morphologies: normal-size and pinpoint colonies. The purposes of the present study were to characterize the small colonies ofL. monocytogenesand to determine if specific genetic changes could explain the triclosan-induced aminoglycoside resistance in both pinpoint and normal-size isolates. Isolates from the pinpoint colonies grew poorly under aerated conditions, but growth was restored by addition of antibiotics. Pinpoint isolates had decreased hemolytic activity under stagnant conditions and a changed spectrum of carbohydrate utilization compared to the wild type and isolates from normal-size colonies. Genome sequence comparison revealed that all seven pinpoint isolates had a mutation in a heme gene, and addition of heme caused the pinpoint isolates to revert to normal colony size. Triclosan-induced gentamicin-resistant isolates had mutations in several different genes, and it cannot be directly concluded how the different mutations caused gentamicin resistance. However, since many of the mutations affected proteins involved in respiration, it seems likely that the mutations affected the active transport of the antibiotic and thereby caused resistance by decreasing the amount of aminoglycoside that enters the bacterial cell. Our study emphasizes that triclosan likely has more targets than justfabIand that exposure to triclosan can cause resistance to antibiotics that enters the cell via active transport. Further studies are needed to elucidate ifL. monocytogenespinpoint isolates could have any clinical impact, e.g., in persistent infections.

scholarly journals Emergence of Multidrug-Resistant Uropathogens harboring ESBL, Carbapenem, Aminoglycosides and AmpC resistant genes from Northern India

2018 ◽  
Author(s):  
Varsha Rani Gajamer ◽  
Amitabha Bhattacharjee ◽  
Deepjyoti Paul ◽  
Birson Ingti ◽  
Arunabha Sarkar ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Antibiotic Resistance Gene ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Aminoglycoside Resistance ◽  
Antibiotic Resistant ◽  
Northern India ◽  
Carbapenem Resistant ◽  
Resistant Genes ◽  
Esbl Producers

ABSTRACTExtended-spectrum β-lactamase (ESBL) producing bacteria acts as a serious threat, and its co-existence with other antibiotic resistant gene makes the clinical scenario worse nowadays. Therefore in this study, we investigated the occurrence of ESBL genes coexisting with carbapenem, AmpC and aminoglycoside resistance gene in uropathogens. Out of 1516 urine samples, 454 showed significant bacteriuria with a prevalence rate of 29.94 %. Escherichia coli (n=340) were found to be the most predominant uropathogen followed by Klebsiella pneumoniae (n=92), Pseudomonas aeruginosa (n=10) and Proteus mirabilis (n=9). Among the total uropathogens, sixty-three ESBL-producers were identified which included blaCTX-M-15 (n=32), followed by blaCTX-M-15 + blaOXA-2 (n=15), blaCTX-M-15 + blaOXA-2 + blaTEM (n=6), blaOXA-2 (n=5), blaOXA-2 + blaSHV-76 (n=1), blaTEM+SHV-76 (n= 1) and blaTEM (n=1). All ESBL genes were found on plasmid incompatibility types: HI1, I1, FIA+FIB, FIA and Y and were horizontally transferable. Among 63 ESBL-producers, 59 isolates harboured carbapenem-resistant genes which included blaNDM-5 (n=48), blaNDM-5 + blaOXA-48 (n=5), blaNDM-5 + blaIMP (n=5) and blaNDM-5 + blaIMP + blaVIM (n=1). The ESBL producing uropathogens also harbored 16S rRNA methylase genes which included rmtB (n=9), rmtA (n=4), rmtC (n=1) and ArmA (n=1) followed by AmpC genes which includes CIT (n=8) and DHA-1 (n=1) genes. Imipenem and gentamicin were found to be more effective. We speculating, this is the first report showing the prevalence of multidrug-resistant uropathogens in this area demanding regular surveillance for such resistance mechanisms which will be useful for health personnel to treat ESBL infection and its co-existence with another antibiotic resistance gene.

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