scholarly journals Autophagy-deficient Schizosaccharomyces pombe mutants undergo partial sporulation during nitrogen starvation

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3816-3826 ◽  
Author(s):  
Hiroyuki Mukaiyama ◽  
Shiro Kajiwara ◽  
Akira Hosomi ◽  
Yuko Giga-Hama ◽  
Naotaka Tanaka ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Nitrogen Source ◽  
Environmental Changes ◽  
Nitrogen Starvation ◽  
Nitrogen Sources ◽  
Vacuole Fusion ◽  
Sporulation Process

Autophagy is triggered when organisms sense radical environmental changes, including nutritional starvation. During autophagy, cytoplasmic components, including organelles, are enclosed within autophagosomes and are degraded upon lysosome–vacuole fusion. In this study, we show that processing of GFP-tagged Atg8 can serve as a marker for autophagy in the fission yeast Schizosaccharomyces pombe. Using this marker, 13 Atg homologues were also found to be required for autophagy in fission yeast. In budding yeast, autophagy-deficient mutants are known to be sterile, whereas in fission yeast we found that up to 30 % of autophagy-defective cells with amino acid auxotrophy were able to recover sporulation when an excess of required amino acids was supplied. Furthermore, we found that approximately 15 % of the autophagy-defective cells were also able to sporulate when a prototrophic strain was subjected to nitrogen starvation, which suggested that fission yeast may store sufficient intracellular nitrogen to allow partial sporulation under nitrogen-limiting conditions, although the majority of the nitrogen source is supplied by autophagy. Monitoring of the sporulation process revealed that the process was blocked non-specifically at various stages in the atg1Δ and atg12Δ mutants, possibly due to a shortage of amino acids. Taking advantage of this partial sporulation ability of fission yeast, we sought evidence for the existence of a recycling system for nitrogen sources during starvation.

scholarly journals Amino Acid Catabolism by an areA-Regulated Gene Encoding an l-Amino Acid Oxidase with Broad Substrate Specificity in Aspergillus nidulans

2005 ◽  
Vol 71 (7) ◽  
pp. 3551-3555 ◽  
Author(s):  
Meryl A. Davis ◽  
Marion C. Askin ◽  
Michael J. Hynes
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Nitrogen Sources ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Broad Substrate Specificity ◽  
Strong Growth

ABSTRACT The filamentous fungus Aspergillus nidulans can use a wide range of compounds as nitrogen sources. The synthesis of the various catabolic enzymes needed to breakdown these nitrogen sources is regulated by the areA gene, which encodes a GATA transcription factor required to activate gene expression under nitrogen-limiting conditions. The areA102 mutation results in pleiotropic effects on nitrogen source utilization, including better growth on certain amino acids as nitrogen sources. Mutations in the sarA gene were previously isolated as suppressors of the strong growth of an areA102 strain on l-histidine as a sole nitrogen source. We cloned the sarA gene by complementation of a sarA mutant and showed that it encodes an l-amino acid oxidase enzyme with broad substrate specificity. Elevated expression of this enzyme activity in an areA102 background accounts for the strong growth of these strains on amino acids that are substrates for this enzyme. Loss of function sarA mutations, which abolish the l-amino acid oxidase activity, reverse the areA102 phenotype. Growth tests with areA102 and sarA mutants show that this enzyme is the primary route of catabolism for some amino acids, while other amino acids are metabolized through alternative pathways that yield either ammonium or glutamate for growth.

scholarly journals The S. pombe CDK5 ortholog Pef1 regulates sexual differentiation through control of the TORC1 pathway and autophagy

2020 ◽  
Vol 133 (17) ◽  
pp. jcs247817
Author(s):  
Shinya Matsuda ◽  
Ushio Kikkawa ◽  
Haruka Uda ◽  
Akio Nakashima
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Sexual Differentiation ◽  
Environmental Changes ◽  
Nitrogen Starvation ◽  
General Strategy ◽  
Positive Regulation ◽  
Starvation Response ◽  
Double Deletion ◽  
Early Phases

ABSTRACTIn Schizosaccharomyces pombe, a general strategy for survival in response to environmental changes is sexual differentiation, which is triggered by TORC1 inactivation. However, mechanisms of TORC1 regulation in fission yeast remain poorly understood. In this study, we found that Pef1, which is an ortholog of mammalian CDK5, regulates the initiation of sexual differentiation through positive regulation of TORC1 activity. Conversely, deletion of pef1 leads to activation of autophagy and subsequent excessive TORC1 reactivation during the early phases of the nitrogen starvation response. This excessive TORC1 reactivation results in the silencing of the Ste11-Mei2 pathway and mating defects. Additionally, we found that pef1 genetically interacts with tsc1 and tsc2 for TORC1 regulation, and physically interacts with three cyclins, Clg1, Pas1 and Psl1. The double deletion of clg1 and pas1 promotes activation of autophagy and TORC1 during nitrogen starvation, similar to what is seen in pef1Δ cells. Overall, our work suggests that Pef1–Clg1 and Pef1–Pas1 complexes regulate initiation of sexual differentiation through control of the TSC–TORC1 pathway and autophagy.

scholarly journals The amino acid sequence of the small monomeric phosphoglycerate mutase from the fission yeast Schizosaccharomyces pombe

1994 ◽  
Vol 297 (3) ◽  
pp. 603-608 ◽  
Author(s):  
J Nairn ◽  
N C Price ◽  
L A Fothergill-Gilmore ◽  
G E Walker ◽  
J E Fothergill ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Phosphoglycerate Mutase ◽  
Yeast Saccharomyces Cerevisiae ◽  
Reading Frame ◽  
C Terminus ◽  
Contact Residues

The amino acid sequence of the monomeric 2,3-bisphosphoglycerate (BPG)-dependent phosphoglycerate mutase (PGAM) from the fission yeast Schizosaccharomyces pombe has been determined. Amino acid sequencing of proteolytic fragments of the enzyme showed the S. pombe mutase to be similar in sequence to the tetrameric enzyme of baker's yeast (Saccharomyces cerevisiae). An S. pombe cDNA library was screened using a PCR fragment generated from two oligonucleotides complementary to sequences encoding the regions at the two active-site histidine residues. The 0.63 kb cDNA encoded an open reading frame of 210 amino acids. This sequence agreed completely with sequences of peptides derived from the purified protein. The amino acid sequence of S. pombe PGAM is 43% identical with that of S. cerevisiae PGAM and shows an equally high degree of identity with BPG-dependent PGAMs from other sources. However, the sequence of the S. pombe enzyme differs from other BPG-dependent enzymes in three important ways: (i) it does not contain the alanine- and lysine-rich sequence of amino acids at the C-terminus which have been proposed to constitute a flexible tail involved in catalysis; (ii) the sequence spanning residues 122-146 (S. cerevisiae PGAM numbering) is not present in the S. pombe PGAM sequence; in the S. cerevisiae PGAM crystal structure this stretch of sequence has been shown to occur as an extended loop, part of which is involved in inter-subunit interactions; (iii) the amino acid sequence in the region of a second S. cerevisiae inter-subunit contact (residues 74-78) shows radical mutations in the S. pombe enzyme.

Access to 2-Arylquinazolines via Catabolism/Reconstruction of Amino Acids with Insertion of Dimethyl Sulfoxide

2021 ◽  
Author(s):  
Jin-Tian Ma ◽  
Li-Sheng Wang ◽  
Zhi Chai ◽  
Xin-Feng Chen ◽  
Bo-Cheng Tang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dimethyl Sulfoxide ◽  
Nitrogen Source ◽  
Carbon And Nitrogen ◽  
First Time

Quinazoline skeletons are synthesized by amino acids catabolism/reconstruction combined with dimethyl sulfoxide insertion/cyclization for the first time. The amino acid acts as a carbon and nitrogen source through HI-mediated catabolism...

scholarly journals Amino acids whose intracellular levels change most during aging alter chronological lifespan of fission yeast

2020 ◽  
Author(s):  
Charalampos Rallis ◽  
Michael Mülleder ◽  
Graeme Smith ◽  
Yan Zi Au ◽  
Markus Ralser ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Fission Yeast ◽  
Yeast Cells ◽  
Total Amino Acid ◽  
Wild Type ◽  
Chronological Lifespan ◽  
Biomarkers Of Aging ◽  
Concentration Changes ◽  
Amino Acid Levels

AbstractAmino acid deprivation or supplementation can affect cellular and organismal lifespan, but we know little about the role of concentration changes in free, intracellular amino acids during aging. Here, we determine free amino-acid levels during chronological aging of non-dividing fission yeast cells. We compare wild-type with long-lived mutant cells that lack the Pka1 protein of the protein kinase A signalling pathway. In wild-type cells, total amino-acid levels decrease during aging, but much less so in pka1 mutants. Two amino acids strongly change as a function of age: glutamine decreases, especially in wild-type cells, while aspartate increases, especially in pka1 mutants. Supplementation of glutamine is sufficient to extend the chronological lifespan of wild-type but not of pka1Δ cells. Supplementation of aspartate, on the other hand, shortens the lifespan of pka1Δ but not of wild-type cells. Our results raise the possibility that certain amino acids are biomarkers of aging, and their concentrations during aging can promote or limit cellular lifespan.

Amino acid uptake systems in Bacteroides ruminicola

1979 ◽  
Vol 25 (10) ◽  
pp. 1161-1168 ◽  
Author(s):  
Roselynn M. W. Stevenson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nitrogen Sources ◽  
Amino Acid Uptake ◽  
Defined Medium ◽  
High Rate ◽  
Transport Systems ◽  
Acid Uptake ◽  
Chemical Structures ◽  
Kinetic Inhibition

Uptake of amino acids by Bacteroides ruminicola was observed in cells grown in a complete defined medium, containing ammonia as the nitrogen source. A high rate of uptake occurred only in fresh medium, as an inhibitory substance, possibly acetate, apparently accumulated during growth. All amino acids except proline were taken up and incorporated into cold trichloroacetic acid precipitable material. Different patterns of incorporation and different responses to 2,4-dinitrophenol and potassium ferricyanide indicated multiple uptake systems were involved. Kinetic inhibition patterns suggested six distinct systems were present for amino acid uptake, with specificities related to the chemical structures of the amino acids. Thus, the failure of free amino acids to act as sole nitrogen sources for growth of B. ruminicola is not due to the absence of transport systems for these compounds.

Fission yeast autophagy induced by nitrogen starvation generates a nitrogen source that drives adaptation processes

2007 ◽  
Vol 12 (2) ◽  
pp. 155-170 ◽  
Author(s):  
Toshiki A. Kohda ◽  
Kayoko Tanaka ◽  
Mami Konomi ◽  
Mamiko Sato ◽  
Masako Osumi ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Nitrogen Source ◽  
Nitrogen Starvation ◽  
Adaptation Processes

scholarly journals The Schizosaccharomyces pombe homolog of Saccharomyces cerevisiae HAP2 reveals selective and stringent conservation of the small essential core protein domain.

1991 ◽  
Vol 11 (2) ◽  
pp. 611-619 ◽  
Author(s):  
J T Olesen ◽  
J D Fikes ◽  
L Guarente
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Transcriptional Activation ◽  
Core Protein ◽  
Protein Domain ◽  
Yeast Saccharomyces Cerevisiae ◽  
Acid Protein ◽  
Ccaat Box

The fission yeast Schizosaccharomyces pombe is immensely diverged from budding yeast (Saccharomyces cerevisiae) on an evolutionary time scale. We have used a fission yeast library to clone a homolog of S. cerevisiae HAP2, which along with HAP3 and HAP4 forms a transcriptional activation complex that binds to the CCAAT box. The S. pombe homolog php2 (S. pombe HAP2) was obtained by functional complementation in an S. cerevisiae hap2 mutant and retains the ability to associate with HAP3 and HAP4. We have previously demonstrated that the HAP2 subunit of the CCAAT-binding transcriptional activation complex from S. cerevisiae contains a 65-amino-acid "essential core" structure that is divisible into subunit association and DNA recognition domains. Here we show that Php2 contains a 60-amino-acid block that is 82% identical to this core. The remainder of the 334-amino-acid protein is completely without homology to HAP2. The function of php2 in S. pombe was investigated by disrupting the gene. Strikingly, like HAP2 in S. cerevisiae, the S. pombe gene is specifically involved in mitochondrial function. This contrasts to the situation in mammals, in which the homologous CCAAT-binding complex is a global transcriptional activator.

scholarly journals A mixed nitrogen diet and compartmentalized utilization for Mycobacterium tuberculosis replicating in host cells: results of a systems-based analysis

2019 ◽  
Author(s):  
Khushboo Borah ◽  
Martin Beyss ◽  
Axel Theorell ◽  
Huihai Wu ◽  
Piyali Basu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Mycobacterium Tuberculosis ◽  
Nitrogen Source ◽  
Nitrogen Metabolism ◽  
Nitrogen Sources ◽  
Spectral Ratio ◽  
Host Cells ◽  
Ratio Analysis ◽  
Nitrogen Donor

Nitrogen metabolism of Mycobacterium tuberculosis (Mtb) is crucial for the survival and virulence of this pathogen inside host macrophages but little is known about the nitrogen sources acquired from the host or their route of assimilation. Here we performed a systems-based analysis of nitrogen metabolism in intracellullar Mtb and developed 15N-Flux Spectral Ratio Analysis (FSRA) to probe the metabolic cross-talk between the host cell and Mtb. We demonstrate that intracellular Mtb acquires nitrogen from multiple amino acids in the macrophage including glutamate, glutamine, aspartate, alanine, glycine and valine, with glutamine being the predominant nitrogen donor. Each nitrogen source is uniquely assimilated into specific intracellular pools indicating compartmentalised metabolism. This was not observed for in vitro-grown Mtb indicating that there is a switch in nitrogen metabolism when the pathogen enters the intracellular environment. These results provide clues about the potential metabolic targets for development of innovative anti-tuberculosis therapies.

scholarly journals Senescence and entrenchment in evolution of amino acid sites

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
A. V. Stolyarova ◽  
E. Nabieva ◽  
V. V. Ptushenko ◽  
A. V. Favorov ◽  
A. V. Popova ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Adaptive Evolution ◽  
Protein Evolution ◽  
Environmental Changes ◽  
Acid Sites ◽  
Analytical Modelling ◽  
Site Change ◽  
A Site ◽  
Positively Selected Sites

Abstract Amino acid propensities at a site change in the course of protein evolution. This may happen for two reasons. Changes may be triggered by substitutions at epistatically interacting sites elsewhere in the genome. Alternatively, they may arise due to environmental changes that are external to the genome. Here, we design a framework for distinguishing between these alternatives. Using analytical modelling and simulations, we show that they cause opposite dynamics of the fitness of the allele currently occupying the site: it tends to increase with the time since its origin due to epistasis (“entrenchment”), but to decrease due to random environmental fluctuations (“senescence”). By analysing the genomes of vertebrates and insects, we show that the amino acids originating at negatively selected sites experience strong entrenchment. By contrast, the amino acids originating at positively selected sites experience senescence. We propose that senescence of the current allele is a cause of adaptive evolution.

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