scholarly journals Inhibition of Catalase by Antisense RNA Increases Susceptibility to Oxidative Stress and Chilling Injury in Transgenic Tomato Plants

1999 ◽  
Vol 124 (4) ◽  
pp. 330-336 ◽  
Author(s):  
Kanogwan Kerdnaimongkol ◽  
William R. Woodson
Keyword(s):  
Oxidative Stress ◽  
Transgenic Plants ◽  
Stress Tolerance ◽  
Catalase Activity ◽  
Chilling Stress ◽  
Chilling Injury ◽  
Fold Increase ◽  
Transgenic Tomato ◽  
Wild Type ◽  
Leaf Extracts

Transgenic tomatoes (Lycopersicon esculentum Mill. `Ohio 8245') expressing an antisense catalase gene (ASTOMCAT1) were used to test the hypothesis that modification of the reactive oxygen species scavenging mechanism in plants can lead to changes in oxidative stress tolerance. A 2- to 8-fold reduction in total catalase activity was detected in the leaf extracts of transformants. A 2-fold increase in levels of H2O2 was observed in the transgenic plants with reduced catalase activity. Electrophoretic characterization of multiple catalase isoforms revealed the specific suppression of CAT1 in transgenic plants. Homozygous plants carrying the antisense catalase transgene were used to study the effect of alteration in the expression of catalase on stress tolerance. Transgenic plants treated with 3% H2O2 showed visible damage within 24 hours and subsequently died. In contrast, wild-type and azygous control plants recovered from the treatment. Transgenic plants did not survive 4 °C chilling stress compared to control wild-type and azygous lines. Physiological analysis of these plants indicated that suppression of catalase activity in transgenic tomato led to enhanced sensitivity to oxidative stress. Our data support a role for catalase in oxidative stress defense system in tomato.

scholarly journals A Helicobacter hepaticus catalase mutant is hypersensitive to oxidative stress and suffers increased DNA damage

2007 ◽  
Vol 56 (4) ◽  
pp. 557-562 ◽  
Author(s):  
Yang Hong ◽  
Ge Wang ◽  
Robert J. Maier
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Catalase Activity ◽  
Insertional Mutagenesis ◽  
Specific Activity ◽  
Bacterial Species ◽  
Helicobacter Hepaticus ◽  
Wild Type ◽  
Crude Cell Extract ◽  
H Pylori

Catalase (KatA) is known to play an important role in oxidative stress resistance in many bacterial species and a homologue exists in Helicobacter hepaticus, a member of the enterohepatic Helicobacter species. Here, a katA mutant was constructed by insertional mutagenesis and its oxidative stress phenotype was investigated. Catalase activity was readily detected [196 units (mg protein crude cell extract)−1] in the wild-type, whereas the mutant strain was deficient in, but not devoid of, activity. In contrast, Helicobacter pylori katA strains lack detectable catalase activity and wild-type H. pylori generally contains higher specific activity than H. hepaticus. Wild-type H. hepaticus cells tolerated 6 % O2 for growth, whilst the katA mutant could not survive at this oxygen level. Even at the optimal O2 level, the growth of the H. hepaticus katA strain was severely inhibited, which is also in contrast to H. pylori katA strains. Wild-type H. hepaticus cells withstood exposure to 100 mM H2O2 but the katA mutant cells were killed by the same treatment. Wild-type cells suffered no significant DNA damage by H2O2 treatment (100 mM for 6 min), whilst the same treatment resulted in severe DNA fragmentation in the katA mutant. Thus H. hepaticus KatA plays an important role as an antioxidant protein.

Biochemical identification of the OsMKK6–OsMPK3 signalling pathway for chilling stress tolerance in rice1

2012 ◽  
Vol 443 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Guosheng Xie ◽  
Hideki Kato ◽  
Ryozo Imai
Keyword(s):  
Protein Kinase ◽  
Low Temperature ◽  
Transgenic Plants ◽  
Stress Tolerance ◽  
Chilling Stress ◽  
Active Form ◽  
Signalling Pathway ◽  
Kinase Assay ◽  
Mapk Kinase

MAPK (mitogen-activated protein kinase) pathways have been implicated in stress signalling in plants. In the present study, we performed yeast two-hybrid screening to identify partner MAPKs for OsMKK (Oryza sativa MAPK kinase) 6, a rice MAPK kinase, and revealed specific interactions of OsMKK6 with OsMPK3 and OsMPK6. OsMPK3 and OsMPK6 each co-immunoprecipitated OsMKK6, and both were directly phosphorylated by OsMKK6 in vitro. An MBP (myelin basic protein) kinase assay of the immunoprecipitation complex indicated that OsMPK3 and OsMPK6 were activated in response to a moderately low temperature (12°C), but not a severely low temperature (4°C) in rice seedlings. A constitutively active form of OsMKK6, OsMKK6DD, showed elevated phosphorylation activity against OsMPK3 and OsMPK6 in vitro. OsMPK3, but not OsMPK6, was constitutively activated in transgenic plants overexpressing OsMKK6DD, indicating that OsMPK3 is an in vivo target of OsMKK6. Enhanced chilling tolerance was observed in the transgenic plants overexpressing OsMKK6DD. Taken together, our data suggest that OsMKK6 and OsMPK3 constitute a moderately low-temperature signalling pathway and regulate cold stress tolerance in rice.

scholarly journals NAFENOPIN-INDUCED HEPATIC MICROBODY (PEROXISOME) PROLIFERATION AND CATALASE SYNTHESIS IN RATS AND MICE

1974 ◽  
Vol 61 (2) ◽  
pp. 344-358 ◽  
Author(s):  
Jarnardan K. Reddy ◽  
Daniel L. Azarnoff ◽  
Donald J. Svoboda ◽  
Jada D. Prasad
Keyword(s):  
Catalase Activity ◽  
Fold Increase ◽  
Female Rats ◽  
Male Rats ◽  
Wild Type ◽  
Rapid Reduction ◽  
Male And Female ◽  
Male And Female Rats ◽  
Rats And Mice ◽  
Catalase Protein

Nafenopin (2-methyl-2[p-(1,2,3,4-tetrahydro-1-naphthyl)phenoxy]-propionic acid; Su-13437), a potent hypolipidemic compound, was administered in varying concentrations in ground Purina Chow to male and female rats, wild type (Csa strain) mice and acatalasemic (Csb strain) mice to determine the hepatic microbody proliferative and catalase-inducing effects. In all groups of animals, administration of nafenopin at dietary levels of 0.125% and 0.25% produced a significant and sustained increase in the number of peroxisomes. The hepatic microbody proliferation in both male and female rats and wild type Csa strain mice treated with nafenopin was of the same magnitude and was associated with a two-fold increase in catalase activity and in the concentration of catalase protein. The increase in microbody population in acatalasemic mice, although not accompanied by increase in catalase activity, was associated with a twofold increase in the amount of catalase protein. The absence of sex difference in microbody proliferative response in nafenopin-treated rats and wild type mice is of particular significance, since ethyl-α-p-chlorophenoxyisobutyrate (CPIB)-induced microbody proliferation and increase in catalase activity occurred only in males. Nafenopin can, therefore, be used as an inducer of microbody proliferation and of catalase synthesis in both sexes of rats and mice. The serum glycerol-glycerides were markedly lowered in all the animals given nafenopin, which paralleled the increase in liver catalase. All the above effects of nafenopin were fully reversed when the drug was withdrawn from the diet of male rats. During reversal, several microbody nucleoids were seen free in the hyaloplasm or in the dilated endoplasmic reticulum channels resulting from a rapid reduction in microbody matrix proteins after the withdrawal of nafenopin from the diet. Because of microbody proliferation and catalase induction with increasing number of hypolipidemic compounds, additional studies are necessary to determine the interrelationships of microbody proliferation, catalase induction, and hypolipidemia.

scholarly journals Ayurvedic Amalaki Rasayana promotes improved stress tolerance and thus has anti-aging effects in Drosophila melanogaster

2016 ◽  
Author(s):  
Vibha Dwivedi ◽  
Subhash C. Lakhotia
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Drosophila Melanogaster ◽  
Stress Tolerance ◽  
Healthy Aging ◽  
Phyllanthus Emblica ◽  
Wild Type ◽  
Aging Effects ◽  
Sod Activity ◽  
Normal Food

AbstractEthnopharmacological relevanceAmalaki Rasayana (AR) is a common Ayurvedic herbal formulation of Phyllanthus emblica fruits and other ingredients and is used for general good health and healthy aging. We earlier reported it to improve life history traits and to suppress neurodegeneration as well as induced apoptosis in Drosophila.Aim of the studyTo examine effects of dietary AR supplement on cell stress responses in Drosophila melanogaster.Materials and methodsLarvae/flies, reared on normal food or on that supplemented with 0.5% (w/v) AR, were exposed to crowding, thermal or oxidative stress and examined for survival, stress tolerance and levels of lipid peroxides, SOD and HSPs.ResultsWild type larvae/flies reared on AR supplemented food survived the various cell stresses much better than those reared on normal food. AR-fed mutant park13 or DJ-1βDelta93 (Parkinson’s disease model) larvae, however, showed only partial or no protection, respectively, against paraquat-induced oxidative stress, indicating essentiality of DJ-1β for AR mediated oxidative stress tolerance. AR feeding reduced the accumulation of reactive oxygen species (ROS) and lipid peroxidation even in aged (35 day old) wild type flies while enhancing superoxide dismutase (SOD) activity. We show for the first time that while Hsp70 or Hsp83 expression under normal or stress conditions was not differentially affected by AR feeding, Hsp27 levels were elevated in AR fed wild type control as well as heat shocked larvae. Therefore, besides the known anti-oxidant activity of Phyllanthus emblica fruits, dietary AR also enhances cellular levels of Hsp27.ConclusionIn the context of the reported “anti-aging” and “healthy-aging” effects of AR, the present in vivo study on a model organisms shows that AR feeding significantly improves tolerance to a variety of cell stresses through reduced ROS and lipid peroxidation and enhanced SOD activity and Hsp27. Such improved cellular defences following dietary AR provide better homeostasis and thereby improve the life-span and quality of organism’s life.

scholarly journals Overexpression of AtAHL20 causes delayed flowering in Arabidopsis via repression of  FT expression

2020 ◽  
Author(s):  
Reuben Tayengwa ◽  
Pushpa Sharma-Koirala ◽  
Courtney F. Pierce ◽  
Breanna E Werner ◽  
Michael M Neff
Keyword(s):  
Drought Stress ◽  
Transgenic Plants ◽  
Gene Family ◽  
Stress Tolerance ◽  
Flowering Time ◽  
Camelina Sativa ◽  
Negative Regulator ◽  
Wild Type ◽  
Late Flowering ◽  
Drought Stress Tolerance

Abstract Background The 29-member Arabidopsis AHL gene family is classified into three main classes based on nucleotide and protein sequence evolutionary differences. These differences include the presence or absence of introns, type and/or number of conserved AT-hook and PPC domains. AHL gene family members are divided into two phylogenetic clades, Clade-A and Clade-B. A majority of the 29 members remain functionally uncharacterized. Furthermore, the biological significance of the DNA and peptide sequence diversity, observed in the conserved motifs and domains found in the different AHL types, is a subject area that remains largely unexplored. Results Transgenic plants overexpressing AtAHL20 flowered later than the wild type. Transcript accumulation analyses showed that 35S:AtAHL20 plants contained reduced FT, TSF, AGL8 and SPL3 mRNA levels. Similarly, overexpression of AtAHL20’s orthologue in Camelina sativa, Arabidopsis’ closely related Brassicaceae family member species, conferred a late-flowering phenotype via suppression of CsFT expression. In addition, 35S:AtAHL20 seedlings exhibited suppressed hypocotyl length and enhanced water stress tolerance. However, overexpression of an aberrant AtAHL20 gene harboring a missense mutation in the AT-hook domain’s highly conserved R-G-R core motif abolished the late-flowering phenotype. Data from targeted yeast-two-hybrid assays showed that AtAHL20 interacted with itself and several other Clade-A Type-I AHLs which have been previously implicated in flowering-time regulation: AtAHL22, AtAHL27 and AtAHL29. Conclusion We showed via gain-function analysis that AtAHL20 is a negative regulator of FT expression, as well as other downstream flowering time regulating genes. A similar outcome in Camelina sativa transgenic plants overexpressing CsAHL20 suggest that this is a conserved function. Additionally, overexpression of AtAHL20 resulted in shorter hypocotyls and enhanced drought stress tolerance compared to wild-type plants. Our results demonstrate that AtAHL20 is a negative regulator of transition to flowering and hypocotyl elongation, but a positive regulator of drought stress tolerance.

scholarly journals E-cigarette aerosol exacerbates cardiovascular oxidative stress in mice with an inactive aldehyde dehydrogenase 2 enzyme

2021 ◽  
Author(s):  
Xuan Yu ◽  
Xiaocong Zeng ◽  
Feng Xiao ◽  
Ri Chen ◽  
Pritam Sinharoy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Aldehyde Dehydrogenase ◽  
Genetic Variant ◽  
Lipid Peroxide ◽  
Fold Increase ◽  
Protein Carbonyl ◽  
World Population ◽  
Wild Type ◽  
Aldehyde Dehydrogenase 2 ◽  
Aerosol Exposure

Aims: E-cigarette aerosol containing aldehydes, including acetaldehyde, are metabolized by the enzyme aldehyde dehydrogenase 2 (ALDH2). However, little is known how aldehyde exposure from e-cigarettes, when coupled with an inactivating ALDH2 genetic variant, ALDH2*2 (present in 8% of the world population), affects cardiovascular oxidative stress. The aim of this study was to determine how e-cigarette aerosol exposure, when coupled with genetics, impacts cardiovascular oxidative stress in wild type ALDH2 and ALDH2*2 knock-in mice. Methods and Results: Using selective ion flow mass spectrometry, we determined that e-cigarette aerosol contains acetaldehyde that are 10-fold higher than formaldehyde or acrolein. Next, using wild type ALDH2 and ALDH2*2 knock-in rodents, we identified organ-specific differences in ALDH2 with the heart having 1.5-fold less ALDH2 enzyme activity relative to the liver and lung. In isolated cardiac myocytes, acetaldehyde exposure (30seconds, 0.1-1μM) caused a 4-fold greater peak in calcium levels for ALDH2*2 relative to ALDH2 cardiomyocytes. ALDH2*2 cardiomyocytes exposed to acetaldehyde also demonstrated a 2-fold increase in ROS production and 2.5-fold increase in 4HNE protein adducts relative to ALDH2 cardiomyocytes. For intact rodents, ALDH2*2 knock-in mice exposed to e-cigarette aerosol had an increased heart rate beginning 5 days after exposure compared to wild type ALDH2 mice (775±30bpm versus 679±33bpm, respectively, *p<0.01, n=7-8 per group). E-cigarette aerosol exposure also exacerbated oxidative stress in ALDH2*2 heart homogenates, including a 1.3-fold higher protein carbonyl level, a 1.7-fold higher lipid peroxide level and 1.5-fold greater phosphorylation of NF-κB relative to wild type ALDH2 homogenates. Conclusions: The increased oxidative stress from e-cigarette aerosol aldehydes triggers the proinflammatory NF-κB pathway. As ALDH2 expression and activity is lower in the heart relative to the lung, the heart could be more susceptible to increases in cardiovascular oxidative stress from e-cigarette aerosol; particularly for those carrying an ALDH2*2 genetic variant which limits acetaldehyde metabolism.

scholarly journals Overexpression of Mannitol-1-Phosphate Dehydrogenase Increases Mannitol Accumulation and Adds Protection Against Chilling Injury in Petunia

2005 ◽  
Vol 130 (4) ◽  
pp. 605-610 ◽  
Author(s):  
Yu-Jen Chiang ◽  
C. Stushnoff ◽  
A.E. McSay ◽  
M.L. Jones ◽  
H.J. Bohnert
Keyword(s):  
Chilling Stress ◽  
Chilling Injury ◽  
Dry Weight ◽  
Wild Type ◽  
Gene Encoding ◽  
E Coli ◽  
Horticultural Crops ◽  
Transgenic Lines ◽  
And Control

Petunia ×hybrida (Hook) Vilm. cv. Mitchell was transformed with an E. coli gene encoding mannitol-1-phosphate dehydrogenase (mtlD). Four plant lines that grew on kanamycin and contained the mtlD transgene were identified. Two of these lines contained high levels of mannitol [high-mannitol lines M3 and M8; mean mannitol = 3.39 μmol·g-1 dry weight (DW)] compared to nontransformed wild-type plants (0.86 μmol·g-1 DW), while two lines had mannitol levels similar to wild-type plants (low-mannitol lines M2 and M9; mean mannitol = 1.05 μmol·g-1 DW). Transgenic and control plants were subjected to chilling stress (3 ± 0.5 °C day/0 ± 0.5 °C night, 12-hour photoperiod and 75% relative humidity) to evaluate the role of mannitol in chilling tolerance. Based upon foliage symptoms and membrane leakage after a 3-week chilling treatment, the high-mannitol containing lines, M3 and M8, were more tolerant of chilling stress than the low-mannitol containing transgenic lines, M2 and M9, and wild-type. Under nonchilling conditions mannitol was the only carbohydrate that differed among transgenic lines, but all carbohydrates were present. When subjected to chilling stress, mannitol levels dropped by 75%, sucrose by 52%, and inositol by 54% in the low-mannitol lines (M2 and M9). In M3 and M8, the high-mannitol lines, mannitol levels decreased by 36%, sucrose by 25%, and inositol by 56%, respectively. Raffinose increased 2- to 3-fold in all lines following exposure to low-temperature chilling stress. In the higher mannitol lines only 0.04% to 0.06% of the total osmotic potential generated from all solutes could be attributed to mannitol, thus its action is more like that of an osmoprotectant rather than an osmoregulator. This study demonstrates that metabolic engineering of osmoprotectant synthesis pathways can be used to improve stress tolerance in horticultural crops.

scholarly journals The Novel ncRNA OsiR Positively Regulates Expression of katE2 and is Required for Oxidative Stress Tolerance in Deinococcus radiodurans

2020 ◽  
Vol 21 (9) ◽  
pp. 3200 ◽  
Author(s):  
Lihua Gao ◽  
Xiaonan Chen ◽  
Ye Tian ◽  
Yongliang Yan ◽  
Yuhua Zhan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Stress Tolerance ◽  
Catalase Activity ◽  
Target Genes ◽  
Deinococcus Radiodurans ◽  
Oxidative Stress Response ◽  
Sequencing Analysis ◽  
Translation Efficiency ◽  
Oxidative Stress Tolerance

Deinococcus radiodurans is a polyextremophilic bacterium well known for its extreme resistance to irradiation, oxidative stress, and other damaging conditions. Many small noncoding RNAs (ncRNAs) in D. radiodurans have been identified by deep sequencing analysis and computational predictions. However, the precise roles of ncRNAs and their target genes in the oxidative stress response have not been investigated. Here, we report the identification and characterization of a novel ncRNA named OsiR (for oxidative stress-induced ncRNA). Oxidative stress tolerance analysis showed that deleting osiR significantly decreased viability, total antioxidant capacity, and catalase activity in D. radiodurans under oxidative stress conditions. Comparative phenotypic and qRT-PCR analyses of an osiR mutant identify a role of OsiR in regulating the expression of the catalase gene katE2. Microscale thermophoresis and genetic complementation showed that a 21-nt sequence in the stem–loop structure of OsiR (204–244 nt) directly base pairs with its counterpart in the coding region of katE2 mRNA (843–866 nt) via a 19 nt region. In addition, deletion of katE2 caused a significant reduction of catalase activity and oxidative stress tolerance similar to that observed in an osiR mutant. Our results show that OsiR positively regulates oxidative stress tolerance in D. radiodurans by increasing the mRNA stability and translation efficiency of katE2. This work provides a new regulatory pathway mediated by ncRNA for the oxidative stress response that most likely contributes to the extreme tolerances of D. radiodurans.

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