Search results for "Mutant"

Following the very initial growth of biological RNA viral clones

2005

Due to their extremely high genetic diversity, which is a direct consequence of high mutation rates, RNA viruses are often described as molecular quasispecies. According to this theory, RNA virus populations cannot be understood in terms of individual viral clones, as they are clouds of interconnected mutants, but this prediction has not yet been demonstrated experimentally. The goal of this study was to determine the fitness of individual clones sampled from a given RNA virus population, a necessary previous step to test the above prediction. To do so, limiting dilutions of a vesicular stomatitis virus population were employed to isolate single viral clones and their initial growth dynamic…

Polymorphisms of inversions and Adh alleles in eye colour mutant experimental populations of Drosophila melanogaster

1987

Transgenic Expression of a Toxin-Coding Killer Virus of the Yeast Zygosaccharomyces bailii in Saccharomyces cerevisiae: Genetic Evidence for a Possib…

1996

The killer toxin-secreting yeast Zygosaccharomyces bailii 412 contains two cytoplasmically inherited double-stranded RNA (dsRNA) viruses (ZbV-L, ZbV-M) responsible for the expression of a killer phenotype in its infected host. While ZbV-L functions as a classical helpervirus by providing capsid (cap) and RNA polymerase functions (cap/pol) necessary for packaging and replication of both viruses, M-dsRNA-containing killer viruses (ZbV-M) are satellites of ZbV-L that contain the genetic information for toxin production only. Both viruses were shown to be sufficient to confer the Z. bailii killer phenotype upon transfected spheroplasts of a S. cerevisiae non-killer strain, resulting in toxin-se…

Chromatin structure of the yeast SUC2 promoter in regulatory mutants

1992

We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. Thes…

Open and closed inflorescences: more than simple opposites

2010

The absence of a terminal flower in inflorescences (‘open inflorescences’) is currently explained by the maintenance of putative stem-cells in the central zone (CZ) of the inflorescence meristem (IM) governed by the CLAVATA– WUSCHEL regulatory loop. Disruption of this regulatory pathway, as in Arabidopsis TERMINAL FLOWER LOCUS 1 mutants, leads to terminal flower production. However, recent studies in other taxa reveal novel mechanisms of inflorescence termination; for example, the SEPALLATA-like MADS-box floral identity gene GERBERA REGULATOR OF CAPITULUM DEVELOPMENT 2 in Gerbera excludes the retention of a CZ as an ontogenetic cause for the openness of these inflorescences. Moreover, compa…

An Enriched European Eel Transcriptome Sheds Light upon Host-Pathogen Interactions with Vibrio vulnificus.

2015

Infectious diseases are one of the principal bottlenecks for the European eel recovery. The aim of this study was to develop a new molecular tool to be used in host-pathogen interaction experiments in the eel. To this end, we first stimulated adult eels with different pathogen- associated molecular patterns (PAMPs), extracted RNA from the immune-related tissues and sequenced the transcriptome.We obtained more than 2x106 reads that were assembled and annotated into 45,067 new descriptions with a notable representation of novel transcripts related with pathogen recognition, signal transduction and the immune response. Then, we designed a DNA-microarray that was used to analyze the early immun…

Analysis of composition, morphology, and biosynthesis of cuticular wax in wild type bilberry (Vaccinium myrtillus L.) and its glossy mutant

2021

Abstract In this study, cuticular wax load, its chemical composition, and biosynthesis, was studied during development of wild type (WT) bilberry fruit and its natural glossy type (GT) mutant. GT fruit cuticular wax load was comparable with WT fruits. In both, the proportion of triterpenoids decreased during fruit development concomitant with increasing proportions of total aliphatic compounds. In GT fruit, a higher proportion of triterpenoids in cuticular wax was accompanied by a lower proportion of fatty acids and ketones compared to WT fruit as well as lower density of crystalloid structures on berry surfaces. Our results suggest that the glossy phenotype could be caused by the absence o…

High osmolarity glycerol (HOG) signalling in Magnaporthe oryzae: Identification of MoYPD1 and its role in osmoregulation, fungicide action, and patho…

2015

AbstractThis study comprises a first functional analysis of an YPD1-homologue in filamentous phytopathogenic fungi and its role in the HOG signalling pathway. We generated a gene deletion mutant of the gene MoYPD1 in Magnaporthe oryzae and characterized the resulting mutant strain. We have shown that MoYpd1p is a component of the phosphorelay system acting in the HOG pathway due to its Y2H protein interaction with the HKs MoHik1p and MoSln1p as well as with the response regulator MoSsk1p. Fungicidal activity of fludioxonil was reported to be based on the inhibition of MoHik1p resulting in hyperactivation of the HOG signalling pathway and lethality. Western analysis proved that both, osmotic…

Rapid adaptation of signaling networks in the fungal pathogen Magnaporthe oryzae

2019

Abstract Background One fundamental question in biology is how the evolution of eukaryotic signaling networks has taken place. “Loss of function” (lof) mutants from components of the high osmolarity glycerol (HOG) signaling pathway in the filamentous fungus Magnaporthe oryzae are viable, but impaired in osmoregulation. Results After long-term cultivation upon high osmolarity, stable individuals with reestablished osmoregulation capacity arise independently from each of the mutants with inactivated HOG pathway. This phenomenon is extremely reproducible and occurs only in osmosensitive mutants related to the HOG pathway – not in other osmosensitive Magnaporthe mutants. The major compatible so…

Characterization of a novel open reading frame, urf a, in the mitochondrial genome of fission yeast: correlation of urf a mutations with a mitochondr…

1991

Between the genes for tRNA(gin) and tRNA(ile) an open reading frame of 227 amino acids has been identified which is unique among known mitochondrial genomes and which has been termed urf a (Lang et al. 1983; Kornrumpf et al. 1984). It uses the "mitochondrial" genetic code, i.e., it contains a TGA codon, whereas all other protein-encoding genes, and all but one intronic open reading frame, use the "standard" genetic code (UGG for tryptophan). A previous paper has demonstrated that "mutator" strains show an increased formation of mitochondrial drug-resistant and respiration-deficient mutants (including deletions). In this paper we show that the mutator activity is correlated with mutations in…