Control of Photosynthesis in Amaranthus edulis Mutants with Reduced Amounts of PEP Carboxylase

1997 ◽  
Vol 24 (4) ◽  
pp. 469 ◽  
Author(s):  
Louisa V. Dever ◽  
Karen J. Bailey ◽  
Richard C. Leegood ◽  
Peter J. Lea
Keyword(s):  
Maximum Rate ◽  
Compensatory Mechanism ◽  
Wild Type ◽  
Pep Carboxylase ◽  
Temperature Changes ◽  
Rate Of Photosynthesis ◽  
Lower Maximum ◽  
Fine Adjustment ◽  
Control Coefficients ◽  
Wild Type Control

Mutants of the NAD-ME plant have been created using sodium azide. These contain reduced activities of PEP carboxylase ranging from 5 to 100% of wild-type. Those with greater than 50% of the wild-type PEPC content showed a lower maximum rate of photosynthesis and reduced carboxylation efficiency compared to the wild-type plants. The PEPC from these heterozygotes was less sensitive to malate inhibition than the PEPC of the wild-type plants and also had an increased phosphorylation state. Mutants containing 45 and 49% of wild-type PEPC exhibited a greater Amax than was observed for the 55, 66 and 70% mutants. We postulate that there is a compensatory mechanism that activates PEPC when the PEPC protein is less than 55% of the wild-type. Control coefficients were measured for PEP carboxylase from wild-type and heterozygous (55%) plants. Results suggest that activation of PEPC by phosphorylation and metabolites may be more an ‘on-off’ switch than a means of fine adjustment of PEPC activity in response to varying factors such as PEPC content, CO2 or temperature changes.

scholarly journals Overexpression of Mucin 1 Suppresses the Therapeutical Efficacy of Disulfiram against Canine Mammary Tumor

Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Ying Zhao ◽  
Zixiang Lin ◽  
Zhaoyan Lin ◽  
Chaoyu Zhou ◽  
Gang Liu ◽  
...  
Keyword(s):  
Mammary Tumor ◽  
Mammary Tumors ◽  
Expression Level ◽  
Canine Mammary Tumor ◽  
Wild Type ◽  
Mucin 1 ◽  
Mammary Tumor Cell ◽  
Mammary Tumor Cell Line ◽  
Canine Mammary Tumors ◽  
Wild Type Control

Mucin 1 (MUC1), a transmembrane protein, is closely associated with the malignancy and metastasis of canine mammary tumors; however, the role of overexpressed MUC1 in the development of cancer cells and response to drug treatment remains unclear. To address this question, we developed a new canine mammary tumor cell line, CIPp-MUC1, with an elevated expression level of MUC1. In vitro studies showed that CIPp-MUC1 cells are superior in proliferation and migration than wild-type control, which was associated with the upregulation of PI3K, p-Akt, mTOR, Bcl-2. In addition, overexpression of MUC1 in CIPp-MUC1 cells inhibited the suppressing activity of disulfiram on the growth and metastasis of tumor cells, as well as inhibiting the pro-apoptotic effect of disulfiram. In vivo studies, on the other side, showed more rapid tumor growth and stronger resistance to disulfiram treatment in CIPp-MUC1 xenograft mice than in wild-type control. In conclusion, our study demonstrated the importance of MUC1 in affecting the therapeutical efficiency of disulfiram against canine mammary tumors, indicating that the expression level of MUC1 should be considered for clinical use of disulfiram or other drugs targeting PI3K/Akt pathway.

scholarly journals Mating in Saccharomyces cerevisiae: The Role of the Pheromone Signal Transduction Pathway in the Chemotropic Response to Pheromone

Genetics ◽  
1997 ◽  
Vol 147 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Kathrin Schrick ◽  
Barbara Garvik ◽  
Leland H Hartwell
Keyword(s):  
Signal Transduction ◽  
Map Kinase ◽  
Transcriptional Activation ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Wild Type ◽  
Mating Partner ◽  
Map Kinase Cascade ◽  
Kinase Cascade ◽  
Wild Type Control

Abstract The mating process in yeast has two distinct aspects. One is the induction and activation of proteins required for cell fusion in response to a pheromone signal; the other is chemotropism, i.e., detection of a pheromone gradient and construction of a fusion site available to the signaling cell. To determine whether components of the signal transduction pathway necessary for transcriptional activation also play a role in chemotropism, we examined strains with null mutations in components of the signal transduction pathway for diploid formation, prezygote formation and the chemotropic process of mating partner discrimination when transcription was induced downstream of the mutation. Cells mutant for components of the mitogen-activated protein (MAP) kinase cascade (ste5, ste20, ste11, ste7 or fus3 kss1) formed diploids at a frequency 1% that of the wild-type control, but formed prezygotes as efficiently as the wild-type control and showed good mating partner discrimination, suggesting that the MAP kinase cascade is not essential for chemotropism. In contrast, cells mutant for the receptor (ste2) or the β or γ subunit (ste4 and stel8) of the G protein were extremely defective in both diploid and prezygote formation and discriminated poorly between signaling and nonsignaling mating partners, implying that these components are important for chemotropism.

scholarly journals Overexpression of vesicle-associated membrane protein PttVAP27-17 as a tool to improve biomass production and the overall saccharification yields in Populus trees

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Madhavi Latha Gandla ◽  
Niklas Mähler ◽  
Sacha Escamez ◽  
Tomas Skotare ◽  
Ogonna Obudulu ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Biomass Production ◽  
Enzymatic Saccharification ◽  
Dry Weight ◽  
Populus Tremula ◽  
Transgenic Trees ◽  
Wild Type ◽  
Glucose Yield ◽  
Transgenic Lines ◽  
Wild Type Control

Abstract Background Bioconversion of wood into bioproducts and biofuels is hindered by the recalcitrance of woody raw material to bioprocesses such as enzymatic saccharification. Targeted modification of the chemical composition of the feedstock can improve saccharification but this gain is often abrogated by concomitant reduction in tree growth. Results In this study, we report on transgenic hybrid aspen (Populus tremula × tremuloides) lines that showed potential to increase biomass production both in the greenhouse and after 5 years of growth in the field. The transgenic lines carried an overexpression construct for Populus tremula × tremuloides vesicle-associated membrane protein (VAMP)-associated protein PttVAP27-17 that was selected from a gene-mining program for novel regulators of wood formation. Analytical-scale enzymatic saccharification without any pretreatment revealed for all greenhouse-grown transgenic lines, compared to the wild type, a 20–44% increase in the glucose yield per dry weight after enzymatic saccharification, even though it was statistically significant only for one line. The glucose yield after enzymatic saccharification with a prior hydrothermal pretreatment step with sulfuric acid was not increased in the greenhouse-grown transgenic trees on a dry-weight basis, but increased by 26–50% when calculated on a whole biomass basis in comparison to the wild-type control. Tendencies to increased glucose yields by up to 24% were present on a whole tree biomass basis after acidic pretreatment and enzymatic saccharification also in the transgenic trees grown for 5 years on the field when compared to the wild-type control. Conclusions The results demonstrate the usefulness of gene-mining programs to identify novel genes with the potential to improve biofuel production in tree biotechnology programs. Furthermore, multi-omic analyses, including transcriptomic, proteomic and metabolomic analyses, performed here provide a toolbox for future studies on the function of VAP27 proteins in plants.

scholarly journals Stress-induced expression of IPT gene in transgenic wheat reduces grain yield penalty under drought

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ailin Beznec ◽  
Paula Faccio ◽  
Daniel J. Miralles ◽  
Leonor G. Abeledo ◽  
Cecilia Decima Oneto ◽  
...  
Keyword(s):  
Grain Yield ◽  
Bread Wheat ◽  
Transcriptional Control ◽  
Field Conditions ◽  
Wild Type ◽  
Ipt Gene ◽  
Receptor Like Kinase ◽  
Biomass Components ◽  
Yield Penalty ◽  
Wild Type Control

Abstract Background The heterologous expression of isopentenyl transferase (IPT) under the transcriptional control of the senescence-associated receptor-like kinase (SARK) promoter delayed cellular senescence and, through it, increased drought tolerance in plants. To evaluate the effect of pSARK::IPT expression in bread wheat, six independent transgenic events were obtained through the biolistic method and evaluated transgene expression, phenology, grain yield and physiological biomass components in plants grown under both drought and well-irrigating conditions. Experiments were performed at different levels: (i) pots and (ii) microplots inside a biosafety greenhouse, as well as under (iii) field conditions. Results Two transgenic events, called TR1 and TR4, outperformed the wild-type control under drought conditions. Transgenic plants showed higher yield under both greenhouse and field conditions, which was positively correlated to grain number (given by more spikes and grains per spike) than wild type. Interestingly, this yield advantage of the transgenic events was observed under both drought and well-watered conditions. Conclusions The results obtained allow us to conclude that the SARK promoter-regulated expression of the IPT gene in bread wheat not only reduced the yield penalty produced by water stress but also led to improved productivity under well-watered conditions.

Ultrastructural characterization of a pigment mutant of the red alga Palmaria palmata

1984 ◽  
Vol 62 (6) ◽  
pp. 1101-1107 ◽  
Author(s):  
C. M. Pueschel ◽  
J. P. van der Meer
Keyword(s):  
Red Alga ◽  
Palmaria Palmata ◽  
Wild Type ◽  
Ultrastructural Examination ◽  
Dark Treatment ◽  
Prolamellar Bodies ◽  
Ultrastructural Characterization ◽  
Wild Type Control

Ultrastructural examination of a green-pigmented mutant of the red alga Palmaria palmata (L.) O. Kuntze revealed unusual features of the chloroplasts. Encircling peripheral thylakoids, characteristic of the wild-type plastids and florideophyte plastids generally, were lacking. Parallel evenly spaced thylakoids occurred in groups, leaving large volumes of thylakoid-free stroma. Irregularly shaped, electron-dense inclusions with an amorphous substructure and diameters up to 3 μm occurred in some plastids. Cells of the sporeling holdfasts contained structures resembling prolamellar bodies. Attempts to induce formation of prolamellar bodies in blades by dark treatment for 5 weeks were unsuccessful. However, some plastids did develop highly corrugated thylakoids with the crests of one thylakoid apposed to the troughs of the adjacent thylakoid. Thylakoid morphology of the wild-type control was not altered by the absence of light.

scholarly journals Two site-directed mutations abrogate enzyme activity but have different effects on the conformation and cellular content of the N-acetylgalactosamine 4-sulphatase protein

1995 ◽  
Vol 307 (2) ◽  
pp. 457-463 ◽  
Author(s):  
D A Brooks ◽  
D A Robertson ◽  
C Bindloss ◽  
T Litjens ◽  
D S Anson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Cell Line ◽  
Protein Level ◽  
Structural Modification ◽  
Wild Type ◽  
Cellular Content ◽  
Control Protein ◽  
Wild Type Control

The sulphatase family of enzymes have regions of sequence similarity, but relatively little is known about either the structure-function relationships of sulphatases, or the role of highly conserved amino acids. The sequence of amino acids CTPSR at position 91-95 of 4-sulphatase has been shown to be highly conserved in all of the sequenced sulphatase enzymes. The cysteine at amino acid 91 of 4-sulphatase was selected for mutation analysis due to its potential role in either the active site, substrate-binding site or part of a key structural domain of 4-sulphatase and due to the absence of naturally occurring mutations in this residue in mucopolysaccharidosis type VI (MPS VI) patients. Two mutations, C91S and C91T, altering amino acid 91 of 4-sulphatase were generated and expressed in Chinese hamster ovary cells. Biochemical analysis of protein from a C91S cell line demonstrated no detectable 4-sulphatase enzyme activity but a relatively normal level of 4-sulphatase polypeptide (180% of the wild-type control protein level). Epitope detection, using a panel of ten monoclonal antibodies, demonstrated that the C91S polypeptide had a similar immunoreactivity to wild-type 4-sulphatase, suggesting that the C91S substitution does not induce a major structural change in the protein. Reduced catalytic activity associated with normal levels of 4-sulphatase protein have not been observed in any of the MPS VI patients tested and all show evidence of structural modification of 4-sulphatase protein with the same panel of antibodies [Brooks, McCourt, Gibson, Ashton, Shutter and Hopwood (1991) Am. J. Hum. Genet. 48, 710-719]. The loss of enzyme activity without a detectable protein conformation change suggests that Cys-91 may be a critical residue in the catalytic process. In contrast, analysis of protein from a C91T cell line revealed low levels of catalytically inactive 4-sulphatase polypeptide (0.37% of the wild-type control protein level) which had missing or masked epitopes, suggesting an altered protein structure or conformation. Subcellular fractionation studies of the C91T cell line demonstrated a high proportion of 4-sulphatase polypeptide content in organelles characteristic of microsomes. The aberrant intracellular localization and the reduced cellular content of 4-sulphatase polypeptide was consistent with the observed structural modification leading to retention and degradation of the protein within an early vacuolar compartment.

scholarly journals Changes in the Fluorescence Tracking of NaV1.6 Protein Expression in a BTBR T+Itpr3tf/J Autistic Mouse Model

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Musaad A. Alshammari ◽  
Mohammad R. Khan ◽  
Fawaz Alasmari ◽  
Abdulaziz O. Alshehri ◽  
Rizwan Ali ◽  
...  
Keyword(s):  
Mouse Model ◽  
Western Blot ◽  
Neuronal Excitability ◽  
Autism Spectrum ◽  
Wild Type ◽  
Western Blot Assay ◽  
Critical Determinant ◽  
Molecular Features ◽  
Voltage Gated Sodium Channels ◽  
Wild Type Control

The axon initial segment (AIS), the site of action potential initiation in neurons, is a critical determinant of neuronal excitability. Growing evidence indicates that appropriate recruitment of the AIS macrocomplex is essential for synchronized firing. However, disruption of the AIS structure is linked to the etiology of multiple disorders, including autism spectrum disorder (ASD), a condition characterized by deficits in social communication, stereotyped behaviors, and very limited interests. To date, a complete understanding of the molecular components that underlie the AIS in ASD has remained elusive. In this research, we examined the AIS structure in a BTBR T+Itpr3tf/J mouse model (BTBR), a valid model that exhibits behavioral, electrical, and molecular features of autism, and compared this to the C57BL/6J wild-type control mouse. Using Western blot studies and high-resolution confocal microscopy in the prefrontal frontal cortex (PFC), our data indicate disrupted expression of different isoforms of the voltage-gated sodium channels (NaV) at the AIS, whereas other components of AIS such as ankyrin-G and fibroblast growth factor 14 (FGF14) and contactin-associated protein 1 (Caspr) in BTBR were comparable to those in wild-type control mice. A Western blot assay showed that BTBR mice exhibited a marked increase in different sodium channel isoforms in the PFC compared to wild-type mice. Our results provide potential evidence for previously undescribed mechanisms that may play a role in the pathogenesis of autistic-like phenotypes in BTBR mice.

scholarly journals Decreased-activity mutants of phosphoglucose isomerase in the cytosol and chloroplast of Clarkia xantiana. Impact on mass-action ratios and fluxes to sucrose and starch, and estimation of Flux Control Coefficients and Elasticity Coefficients

1989 ◽  
Vol 261 (2) ◽  
pp. 457-467 ◽  
Author(s):  
A L Kruckeberg ◽  
H E Neuhaus ◽  
R Feil ◽  
L D Gottlieb ◽  
M Stitt
Keyword(s):  
Light Intensity ◽  
Starch Synthesis ◽  
Phosphoglucose Isomerase ◽  
Wild Type ◽  
Low Light ◽  
Subcellular Compartment ◽  
Flux Control Coefficients ◽  
Substrate Ratio ◽  
Control Coefficients ◽  
Clarkia Xantiana

1. Subcellular-compartment-specific decreased-activity mutants of phosphoglucose isomerase in Clarkia xantiana were used to analyse the control of sucrose and starch synthesis during photosynthesis. Mutants were available in which the plastid phosphoglucose isomerase complement is decreased to 75% or 50% of the wild-type level, and the cytosol complement to 64%, 36% or 18% of the wild-type level. 2. The effects on the [product]/[substrate] ratio and on fluxes to sucrose or starch and the rate of photosynthesis were studied with the use of saturating or limiting light intensity to impose a high or low flux through these pathways. 3. Removal of a small fraction of either phosphoglucose isomerase leads to a significant shift of the [product]/[substrate] ratio away, from equilibrium. We conclude that there is no ‘excess’ of enzyme over that needed to maintain its reactants reasonably close to equilibrium. 4. Decreased phosphoglucose isomerase activity can also alter the fluxes to starch or sucrose. However, the effect on flux does not correlate with the extent of disequilibrium, and also varies depending on the subcellular compartment and on the conditions. 5. The results were used to estimate Flux Control Coefficients for the chloroplast and cytosolic phosphoglucose isomerases. The chloroplast isoenzyme exerts control on the rate of starch synthesis and on photosynthesis in saturating light intensity and CO2, but not at low light intensity. The cytosolic enzyme only exerts significant control when its complement is decreased 3-5-fold, and differs from the plastid isoenzyme in exerting more control in low light intensity. It has a positive Control Coefficient for sucrose synthesis, and a negative Control Coefficient for starch synthesis. 6. The Elasticity Coefficients in vivo of the cytosolic phosphoglucose isomerase were estimated to lie between 5 and 8 in the wild-type. They decrease in mutants with a lowered complement of cytosolic phosphoglucose isomerase. 7. The implications of these results for regulation and for evolution are discussed.

Exercise Can Reverse the Phenotype of Biglycan Deficient Mice

2003 ◽  
Author(s):  
Joseph M. Wallace ◽  
Rupak M. Rajachar ◽  
Xiao-Dong Chen ◽  
Songtao Shi ◽  
Matthew R. Allen ◽  
...  
Keyword(s):  
Skeletal Development ◽  
Skeletal Growth ◽  
Treadmill Running ◽  
Wild Type ◽  
Connective Tissues ◽  
Cross Sectional ◽  
Age Dependent ◽  
Skeletal Phenotype ◽  
Deficient Mice ◽  
Wild Type Control

Biglycan (Bgn) is a small leucine-rich proteoglycan (SLRP) that is enriched in bone and other skeletal connective tissues and is responsible, in part, for the regulation of postnatal skeletal growth (Bianco, 1990). Mice lacking Bgn display reduced skeletal development and a lower peak bone mass that leads to age-dependent osteopenia (Xu, 1998). We hypothesized that mechanical loading could reverse the skeletal phenotype of Bgn knockout mice. To test this hypothesis, we determined the effects of treadmill running on the geometric, mechanical and mineral properties of Bgn deficient mice bones. After sacrifice, femora and tibiae were tested in 4 point bending and cross-sectional geometric properties and bone mineral parameters were measured. Exercise was able to partially reverse the skeletal phenotype of the Bgn knockouts by increasing both the geometric and mechanical properties of the tibiae to values equal to or greater than those of wild type control mice.

scholarly journals Characterization of gamma irradiation-induced mutations in Arabidopsis mutants deficient in non-homologous end joining

2020 ◽  
Vol 61 (5) ◽  
pp. 639-647
Author(s):  
Yan Du ◽  
Yoshihiro Hase ◽  
Katsuya Satoh ◽  
Naoya Shikazono
Keyword(s):  
Gamma Rays ◽  
Wild Type ◽  
End Joining ◽  
Complex Type ◽  
Single Base ◽  
In The Wild ◽  
Non Homologous End Joining ◽  
Dna Ends ◽  
Wild Type Control

Abstract To investigate the involvement of the non-homologous end joining (NHEJ) pathway in plant mutagenesis by ionizing radiation, we conducted a genome-wide characterization of the mutations induced by gamma rays in NHEJ-deficient Arabidopsis mutants (AtKu70−/− and AtLig4−/−). Although both mutants were more sensitive to gamma rays than the wild-type control, the AtKu70−/− mutant was slightly more sensitive than the AtLig4−/− mutant. Single-base substitutions (SBSs) were the predominant mutations in the wild-type control, whereas deletions (≥2 bp) and complex-type mutations [i.e. more than two SBSs or short insertion and deletions (InDels) separated by fewer than 10 bp] were frequently induced in the mutants. Single-base deletions were the most frequent deletions in the wild-type control, whereas the most common deletions in the mutants were 11–30 bp. The apparent microhomology at the rejoined sites of deletions peaked at 2 bp in the wild-type control, but was 3–4 bp in the mutants. This suggests the involvement of alternative end joining and single-strand annealing pathways involving increased microhomology for rejoining DNA ends. Complex-type mutations comprising short InDels were frequently detected in the mutants, but not in the wild-type control. Accordingly, NHEJ is more precise than the backup pathways, and is the main pathway for rejoining the broken DNA ends induced by ionizing radiation in plants.

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