| oxidative stress and antioxidants in overwintering larvae of cold-hardy goldenrod gall insects | antioxidant and pro-oxidant systems were studied in overwintering larvae of two cold-hardy gall insect species, the freeze-tolerant fly eurosta solidaginis and the freeze-avoiding moth epiblema scudderiana. an increase in the levels of the oxidized form of glutathione suggested slight oxidative stress in both species during the winter. freeze-tolerant eurosta solidaginis larvae generally had decreased activities of antioxidant enzymes in the winter, indicating that these larvae do not face incre ... | 1996 | 9319381 |
| regulation of hexokinase in a freeze avoiding insect: role in the winter production of glycerol. | hexokinase from larvae of the freeze-avoiding goldenrod gall moth, epiblema scudderiana, was purified 20-fold using chromatography on de52 sephadex, phosphocellulose, and blue dextran. final specific activity was 75.8 u/mg and sds-page gave a molecular weight of 94,000 for the monomer. arrhenius plot showed a break at 16 degrees or 12 degrees c in the absence vs. presence of 10% v/v glycerol, indicating a conformational change in the enzyme at lower temperatures but suggesting a stabilizing effe ... | 2001 | 11317333 |
| purification and characterization of protein phosphatase-1 from two cold-hardy goldenrod gall insects. | the catalytic subunit of protein phosphatase-1 (pp-1) was purified to homogeneity from final instar larvae (the overwintering stage) of freeze avoiding (epiblema scudderiana) and freeze tolerant (eurosta solidaginis) cold-hardy insects. arrhenius plots showed that activity of pp-1 from both species was strongly suppressed at low temperature. acidic shifts in ph optima and increased inhibition by okadaic acid were also observed when the enzymes were assayed at 4 degrees c compared with 24 degrees ... | 2002 | 11754094 |
| esmlp, a muscle-lim protein gene, is up-regulated during cold exposure in the freeze-avoiding larvae of epiblema scudderiana. | screening of a cdna library identified transcripts that were up-regulated by cold (4 or -20 degrees c) exposure in larvae of the freeze-avoiding goldenrod gall moth, epiblema scudderiana. one clone contained a full-length open reading frame encoding a protein of 94 amino acids. the gene product, with 79.1% of residues identical with the drosophila lim protein mlp60a, was named esmlp and contained a single lim domain and consensus sequences characteristic of a lim protein. transcript levels rose ... | 2001 | 11812047 |
| protein kinase a: purification and characterization of the enzyme from two cold-hardy goldenrod gall insects. | the catalytic subunit of protein kinase a (pkac) was purified to apparent homogeneity from two species of cold-hardy goldenrod gall insects, epiblema scudderiana and eurosta solidaginis. final specific activity for both enzymes was approximately 74.5 nmol of phosphate transferred per minute per milligram protein. molecular weights were 41 and 40 kda for e. scudderiana and e. solidaginis pkac, respectively. k(m) values at 24 degrees c for the artificial substrate, kemptide, were 38.1+/-4.9 and 3. ... | 2002 | 11891127 |
| responses of protein phosphatases and camp-dependent protein kinase in a freeze-avoiding insect, epiblema scudderiana. | larvae of the goldenrod gall moth, epiblema scudderiana, use the freeze avoidance strategy of winter cold hardiness and show multiple metabolic adaptations for subzero survival including accumulation of large amounts of glycerol as a colligative antifreeze. induction and regulation of cold hardiness adaptations requires the intermediary action of signal transduction enzymes. changes in the activities of several signaling enzymes including camp-dependent protein kinase (pka), protein phosphatases ... | 2006 | 16612809 |
| mitochondria of cold hardy insects: responses to cold and hypoxia assessed at enzymatic, mrna and dna levels. | winter survival for larvae of goldenrod gall insects, the freeze-avoiding epiblema scudderiana, and the freeze tolerant, eurosta solidaginis, includes entry into diapause (a torpid state of arrested development) and expression of a variety of cryoprotective adaptations. diapause and cold winter temperatures, as well as freezing in e. solidaginis, all strongly reduce the need for mitochondrial activity. to evaluate the responses of mitochondria to these conditions, we assessed the maximal activit ... | 2008 | 18252250 |
| in vivo assessment of cold adaptation in insect larvae by magnetic resonance imaging and magnetic resonance spectroscopy. | temperatures below the freezing point of water and the ensuing ice crystal formation pose serious challenges to cell structure and function. consequently, species living in seasonally cold environments have evolved a multitude of strategies to reorganize their cellular architecture and metabolism, and the underlying mechanisms are crucial to our understanding of life. in multicellular organisms, and poikilotherm animals in particular, our knowledge about these processes is almost exclusively due ... | 2008 | 19057644 |
| in cold-hardy insects, seasonal, temperature, and reversible phosphorylation controls regulate sarco/endoplasmic reticulum ca2+-atpase (serca). | winter cold hardiness of insects typically involves one of two major strategies for survival below 0 degrees c: freeze avoidance and freeze tolerance. the two strategies have some common features, including the accumulation of high concentrations of cryoprotectant polyols and the frequent occurrence of diapause. entry into the hypometabolic state of diapause requires coordinated suppression of major atp-consuming metabolic processes, and ion motive atpases are important targets for regulation. t ... | 2010 | 20491546 |
| reversible phosphorylation regulation of nadph-linked polyol dehydrogenase in the freeze-avoiding gall moth, epiblema scudderiana: role in glycerol metabolism. | larvae of the goldenrod gall moth, epiblema scudderiana, use a freeze avoidance strategy of cold hardiness to survive the winter. a key metabolic adaption that supports subzero survival is the accumulation of large amounts of glycerol as a colligative antifreeze. production of glycerol relies on polyol dehydrogenase (pdh) which catalyzes the nadph-dependent conversion of glyceraldehyde into glycerol. kinetic analysis of pdh from e. scudderiana revealed significant changes in properties as a resu ... | 2011 | 21400585 |
| amp-activated protein kinase and metabolic regulation in cold-hardy insects. | winter survival for many insects depends on cold hardiness adaptations as well as entry into a hypometabolic diapause state that minimizes energy expenditure. we investigated whether amp-activated protein kinase (ampk) could be involved in this adaptation in larvae of two cold-hardy insects, eurosta solidaginis that is freeze tolerant and epiblema scudderiana that uses a freeze avoidance strategy. ampk activity was almost 2-fold higher in winter larvae (february) compared with animals collected ... | 2011 | 21787782 |