scholarly journals The biosynthesis of serine and glycine in Pseudomonas AM1 with special reference to growth on carbon sources other than C1 compounds

1971 ◽  
Vol 121 (5) ◽  
pp. 753-762 ◽  
Author(s):  
W. Harder ◽  
J. R. Quayle
Keyword(s):  
Essential Role ◽  
Carbon Sources ◽  
Enzymic Activity ◽  
Serine Hydroxymethyltransferase ◽  
The Other ◽  
Wild Type ◽  
Phosphoserine Phosphatase ◽  
Wild Type Phenotype ◽  
Phosphoglycerate Dehydrogenase ◽  
Serine Biosynthesis

1. A mutant, 20S, of Pseudomonas AM1 was obtained that requires a supplement of serine to grow on succinate, lactate or ethanol. This mutant lacks phosphoserine phosphatase and revertants to wild-type phenotype regained this enzymic activity showing that the phosphorylated pathway of serine biosynthesis is necessary for growth on these three substrates. 2. The requirement for supplemental serine by mutant 20S could be met by glycine, suggesting that Pseudomonas AM1 can obtain C1 units from glycine. 3. Mutant 20S grows on C1 compounds at a lower rate compared with the wild type. Supplementation with serine stimulated the growth rate of the mutant suggesting that the phosphorylated pathway of serine biosynthesis plays some role, but not an essential role, during growth on C1 compounds. 4. A mutant, 82G, was obtained that requires a supplement of glycine to grow on succinate, lactate or ethanol. When grown in such supplemented media, the mutant lacks serine hydroxymethyltransferase and revertants to wild-type phenotype regained enzymic activity showing that during growth on succinate, lactate or ethanol, glycine is made from serine via serine hydroxymethyltransferase, and that the organism can obtain C1 units from glycine. 5. Mutant 82G grew on methanol and then contained serine hydroxymethyltransferase suggesting that this enzyme is necessary for growth on C1 compounds and that Pseudomonas AM1 may synthesize two such enzymes, one used in growth on C1 compounds, the other used in growth on other substrates. Mutant 82G might lack the latter enzyme. 6. Phosphoglycerate dehydrogenase is specifically inhibited by l-serine and the regulatory implications of this are discussed.

scholarly journals Aspects of glycine and serine biosynthesis during growth of Pseudomonas AM1 on C1 compounds

1971 ◽  
Vol 121 (5) ◽  
pp. 763-769 ◽  
Author(s):  
W. Harder ◽  
J. R. Quayle
Keyword(s):  
Serine Hydroxymethyltransferase ◽  
Aminotransferase Activity ◽  
Wild Type ◽  
Amino Groups ◽  
Auxotrophic Mutants ◽  
Wild Type Phenotype ◽  
Glyoxylate Aminotransferase ◽  
Serine Biosynthesis

1. Methanol or formate can replace serine or glycine as supplements for growth on succinate of the auxotrophic mutants 20S and 82G of Pseudomonas AM1, showing that the organism can synthesize glycine and serine in net fashion from C1 units. 2. Double mutants of Pseudomonas 20S and 82G have been prepared (20ST-1 and 82GT-1) that are unable to grow on succinate+1mm-glyoxylate, succinate+2mm-methanol or methanol alone. 3. Mutants 20ST-1 and 82GT-1 lacked serine–glyoxylate aminotransferase activity, and revertants to the phenotype of 20S and 82G regained serine–glyoxylate aminotransferase activity. A total revertant of 82GT-1 to wild-type phenotype regained activities of serine hydroxymethyltransferase and serine–glyoxylate aminotransferase. 4. The activity of serine–glyoxylate aminotransferase in methanol-grown Pseudomonas AM1 is eightfold higher than in the succinate-grown organism. 5. The combined results show that in Pseudomonas AM1 serine–glyoxylate aminotransferase is necessary for growth on C1 compounds and is involved in the conversion of methanol into glycine via glyoxylate. 6. It is suggested that the phosphorylated pathway of serine biosynthesis from phosphoglycerate replenishes the supply of α-amino groups necessary for the flow of glyoxylate through the main assimilatory pathway during growth on C1 compounds.

scholarly journals The UDP-Glc:Glycoprotein Glucosyltransferase Is Essential for Schizosaccharomyces pombe Viability under Conditions of Extreme Endoplasmic Reticulum Stress

1998 ◽  
Vol 143 (3) ◽  
pp. 625-635 ◽  
Author(s):  
Sandra Fanchiotti ◽  
Fabiana Fernández ◽  
Cecilia D'Alessio ◽  
Armando J. Parodi
Keyword(s):  
Cell Viability ◽  
Schizosaccharomyces Pombe ◽  
Double Mutant ◽  
Expression Vector ◽  
The Other ◽  
Wild Type ◽  
Glucosidase Ii ◽  
Wild Type Phenotype ◽  
Polypeptide Chains ◽  
Mutant Cells

Interaction of monoglucosylated oligosaccharides with ER lectins (calnexin and/or calreticulin) facilitates glycoprotein folding but this interaction is not essential for cell viability under normal conditions. We obtained two distinct single Schizosaccharomyces pombe mutants deficient in either one of the two pathways leading to the formation of monoglucosylated oligosaccharides. The alg6 mutant does not glucosy- late lipid-linked oligosaccharides and transfers Man9GlcNAc2 to nascent polypeptide chains and the gpt1 mutant lacks UDP-Glc:glycoprotein glucosyltransferase (GT). Both single mutants grew normally at 28°C. On the other hand, gpt1/alg6 double-mutant cells grew very slowly and with a rounded morphology at 28°C and did not grow at 37°C. The wild-type phenotype was restored by transfection of the double mutant with a GT-encoding expression vector or by addition of 1 M sorbitol to the medium, indicating that the double mutant is affected in cell wall formation. It is suggested that facilitation of glycoprotein folding mediated by the interaction of monoglucosylated oligosaccharides with calnexin is essential for cell viability under conditions of extreme ER stress such as underglycosylation of proteins caused by the alg6 mutation and high temperature. In contrast, gls2/alg6 double-mutant cells that transfer Man9GlcNAc2 and that are unable to remove the glucose units added by GT as they lack glucosidase II (GII), grew at 37°C and had, when grown at 28°C, a phenotype of growth and morphology almost identical to that of wild-type cells. These results indicate that facilitation of glycoprotein folding mediated by the interaction of calnexin and monoglucosylated oligosaccharides does not necessarily require cycles of reglucosylation–deglucosylation catalyzed by GT and GII.

scholarly journals An unusual complementation in non-excitable mutants in Paramecium

2000 ◽  
Vol 76 (2) ◽  
pp. 125-133 ◽  
Author(s):  
ATSUSHI MATSUDA ◽  
YOSHIRO SAIMI ◽  
MIHOKO TAKAHASHI
Keyword(s):  
Genetic Relationship ◽  
The Other ◽  
Unusual Feature ◽  
Marker Genes ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Other Hand ◽  
Wild Type Phenotype ◽  
Allelic Interaction

A non-excitable behavioural mutant, d4-662, was previously characterized as the fourth pawn locus mutant pwD in Paramecium tetraurelia. We now provide data demonstrating that d4-662 is in fact controlled by a pwB allele that has the unusual feature of complementing other pwB alleles in heterozygous F1 progeny. Neither the cytoplasm nor the nucleoplasm of d4-662 cured the mutational defects of pwB and in the reverse combination of d4-662 and pwB, the result was the same. On the other hand, pwA, another non-excitable mutant, was cured upon cross-injection with d4-662 and mutants carrying trichocyst non-discharge marker genes were also cured. This evidence suggests that d4-662 is a new mutant belonging to pwB, and would be better designated as pwB662. Extensive crossbreeding analyses, however, showed an unusual genetic relationship between d4-662 and pwB (pwB95 or pwB96). When d4-662 was crossed with pwB mutants, many progeny expressing wild-type phenotype or mixed clones of wild-type and pawn cells were obtained in the F1. Less than 12·5% expressed the pawn phenotype. The appearance of wild-type progeny in this F1 strongly suggests that an inter-allelic interaction between pwB662 and other pwB alleles may occur during development of the macronucleus.

scholarly journals Pathways leading to and from serine during growth of Pseudomonas AM1 in C1 compounds or succinate

1970 ◽  
Vol 117 (3) ◽  
pp. 563-572 ◽  
Author(s):  
J. Heptinstall ◽  
J. R. Quayle
Keyword(s):  
Dehydrogenase Activity ◽  
Reductase Activity ◽  
Methanol Dehydrogenase ◽  
Wild Type ◽  
Hydroxypyruvate Reductase ◽  
Phosphoglycerate Dehydrogenase ◽  
Specific Activities ◽  
Phenazine Methosulphate ◽  
Serine Biosynthesis ◽  
Enrichment Step

1. The following enzymes of the phosphorylated pathway of serine biosynthesis have been found in methanol- and succinate-grown Pseudomonas AM1: phosphoglycerate dehydrogenase, phosphoserine-α-oxoglutarate aminotransferase and phosphoserine phosphohydrolase. Their specific activities were similar in the organism grown on either substrate. 2. A procedure for preparation of auxotrophic mutants of Pseudomonas AM1 is described involving N-methyl-N′-nitro-N-nitrosoguanidine as mutagen and a penicillin enrichment step. 3. A mutant, M-15A, has been isolated that is unable to grow on methanol and that lacks phenazine methosulphate-linked methanol dehydrogenase. The mutant is able to grow on methylamine, showing that the amine is not oxidized by way of methanol. 4. Loss of methanol dehydrogenase activity in mutant M-15A led to loss of phenazine methosulphate-linked formaldehyde dehydrogenase activity showing that the same enzyme is probably responsible for both activities. 5. A mutant, 20B-L, has been isolated that cannot grow on any C1 compound tested but can grow on succinate. 6. Mutant 20B-L lacks hydroxypyruvate reductase, and revertants that regained the ability to grow on methanol, methylamine and formate contained hydroxypyruvate reductase activity at specific activities similar to that of the wild-type organism. This shows that hydroxypyruvate reductase is necessary for growth on methanol, methylamine and formate but not for growth on succinate. 7. The results suggest that during growth of Pseudomonas AM1 on C1 compounds, serine is converted into 3-phosphoglycerate by a non-phosphorylated pathway, whereas during growth on succinate, phosphoglycerate is converted into serine by a phosphorylated pathway.

scholarly journals Enzymic imbalance in serine metabolism in rat hepatomas

1986 ◽  
Vol 233 (2) ◽  
pp. 617-620 ◽  
Author(s):  
K Snell ◽  
G Weber
Keyword(s):  
Cancer Cells ◽  
Serine Hydroxymethyltransferase ◽  
Cell Renewal ◽  
Regenerating Liver ◽  
High Cell ◽  
Serine Dehydratase ◽  
Phosphoglycerate Dehydrogenase ◽  
Serine Biosynthesis ◽  
Serine Metabolism

The activity of 3-phosphoglycerate dehydrogenase was high in tissues of high cell-renewal capacity, and was increased in neonatal and regenerating liver and, more markedly, in hepatomas. Serine hydroxymethyltransferase activity was present in hepatomas, whereas other enzymes of serine utilization (serine dehydratase and serine aminotransferase) were absent. This enzymic imbalance couples serine biosynthesis preferentially to nucleotide precursor formation in cancer cells.

scholarly journals The Bacillus thuringiensis PlcR-Regulated Gene inhA2 Is Necessary, but Not Sufficient, for Virulence

2003 ◽  
Vol 185 (9) ◽  
pp. 2820-2825 ◽  
Author(s):  
Sinda Fedhila ◽  
Michel Gohar ◽  
Leyla Slamti ◽  
Patricia Nel ◽  
Didier Lereclus
Keyword(s):  
Bacillus Thuringiensis ◽  
Dna Sequence ◽  
Insecticidal Activity ◽  
Oral Infection ◽  
The Other ◽  
Gene Products ◽  
Wild Type ◽  
Transcriptional Fusion ◽  
Dnase I Footprinting ◽  
Wild Type Phenotype

ABSTRACT We previously reported that Bacillus thuringiensis strain 407 Cry 32− secretes a zinc-requiring metalloprotease, InhA2, that is essential for virulence in orally infected insects. Analysis of the inhA2-lacZ transcriptional fusion showed that inhA2 expression is repressed in a PlcR− background. Using DNase I footprinting experiments, we demonstrated that PlcR activates inhA2 transcription directly by binding to a DNA sequence showing a one-residue mismatch with the previously reported PlcR box. It was previously reported that PlcR is essential for B. thuringiensis virulence in oral infection by contributing to the synergistic properties of the spores on the insecticidal activity of the Cry1C protein. We used complementation experiments to investigate whether the PlcR− phenotype was due to the absence of InhA2. The results indicated that overexpression of inhA2 in the ΔplcR strain did not restore the wild-type phenotype. However, virulence was fully restored in the ΔinhA2 complemented mutant. Thus, inhA2 is the first example of a PlcR-regulated gene found to be directly involved in virulence. However, it is not sufficient for pathogenicity when the other members of the PlcR regulon are lacking. This suggests that InhA2 may act in concert with other PlcR-regulated gene products to provide virulence.

Normal Synaptonemal Complex and Abnormal Recombination Nodules in Two Alleles of the Drosophila Meiotic Mutant mei-W68

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1337-1356 ◽  
Author(s):  
Adelaide T C Carpenter
Keyword(s):  
Electron Microscopy ◽  
Synaptonemal Complex ◽  
High Frequency ◽  
Serial Section ◽  
The Other ◽  
Wild Type ◽  
Recombination Nodules ◽  
Section Electron ◽  
Serial Section Electron Microscopy ◽  
Section Electron Microscopy

Abstract The meiotic phenotypes of two mutant alleles of the mei-W68 gene, 1 and L1, were studied by genetics and by serial-section electron microscopy. Despite no or reduced exchange, both mutant alleles have normal synaptonemal complex. However, neither has any early recombination nodules; instead, both exhibit high numbers of very long (up to 2 μm) structures here named “noodles.” These are hypothesized to be formed by the unchecked extension of identical but much shorter structures ephemerally seen in wild type, which may be precursors of early recombination nodules. Although the mei-W68L1 allele is identical to the mei-W681 allele in both the absence of early recombination nodules and a high frequency of noodles (i.e., it is amorphic for the noodle phene), it is hypomorphic in its effects on exchange and late recombination nodules. The differential effects of this allele on early and late recombination nodules are consistent with the hypothesis that Drosophila females have two separate recombination pathways—one for simple gene conversion, the other for exchange.

scholarly journals A Screen for Genes That Function in Abscisic Acid Signaling in Arabidopsis thaliana

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1247-1255 ◽  
Author(s):  
Eiji Nambara ◽  
Masaharu Suzuki ◽  
Suzanne Abrams ◽  
Donald R McCarty ◽  
Yuji Kamiya ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Growth And Development ◽  
Plant Hormone ◽  
The Other ◽  
Aba Signaling ◽  
Wild Type ◽  
Plant Growth And Development ◽  
Diverse Range ◽  
Abscisic Acid Signaling ◽  
Aba Insensitive

Abstract The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development under a diverse range of environmental conditions. To identify genes functioning in ABA signaling, we have carried out a screen for mutants that takes advantage of the ability of wild-type Arabidopsis seeds to respond to (−)-(R)-ABA, an enantiomer of the natural (+)-(S)-ABA. The premise of the screen was to identify mutations that preferentially alter their germination response in the presence of one stereoisomer vs. the other. Twenty-six mutants were identified and genetic analysis on 23 lines defines two new loci, designated CHOTTO1 and CHOTTO2, and a collection of new mutant alleles of the ABA-insensitive genes, ABI3, ABI4, and ABI5. The abi5 alleles are less sensitive to (+)-ABA than to (−)-ABA. In contrast, the abi3 alleles exhibit a variety of differences in response to the ABA isomers. Genetic and molecular analysis of these alleles suggests that the ABI3 transcription factor may perceive multiple ABA signals.

scholarly journals Adaptive Laboratory Evolution of Cupriavidus necator H16 for Carbon Co-Utilization with Glycerol

2019 ◽  
Vol 20 (22) ◽  
pp. 5737 ◽  
Author(s):  
Miriam González-Villanueva ◽  
Hemanshi Galaiya ◽  
Paul Staniland ◽  
Jessica Staniland ◽  
Ian Savill ◽  
...  
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Carbon Sources ◽  
Strain Engineering ◽  
Cupriavidus Necator ◽  
Superior Performance ◽  
Wild Type ◽  
Adaptive Laboratory Evolution ◽  
Laboratory Evolution ◽  
Cupriavidus Necator H16

Cupriavidus necator H16 is a non-pathogenic Gram-negative betaproteobacterium that can utilize a broad range of renewable heterotrophic resources to produce chemicals ranging from polyhydroxybutyrate (biopolymer) to alcohols, alkanes, and alkenes. However, C. necator H16 utilizes carbon sources to different efficiency, for example its growth in glycerol is 11.4 times slower than a favorable substrate like gluconate. This work used adaptive laboratory evolution to enhance the glycerol assimilation in C. necator H16 and identified a variant (v6C6) that can co-utilize gluconate and glycerol. The v6C6 variant has a specific growth rate in glycerol 9.5 times faster than the wild-type strain and grows faster in mixed gluconate–glycerol carbon sources compared to gluconate alone. It also accumulated more PHB when cultivated in glycerol medium compared to gluconate medium while the inverse is true for the wild-type strain. Through genome sequencing and expression studies, glycerol kinase was identified as the key enzyme for its improved glycerol utilization. The superior performance of v6C6 in assimilating pure glycerol was extended to crude glycerol (sweetwater) from an industrial fat splitting process. These results highlight the robustness of adaptive laboratory evolution for strain engineering and the versatility and potential of C. necator H16 for industrial waste glycerol valorization.

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