A comparison of the properties of the phosphofructokinases of the fat body and flight muscle of the adult male desert locust.
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ABSTRACT:
SUBMITTER: Walker PR
PROVIDER: S-EPMC1187520 | biostudies-other | 1969 Feb
REPOSITORIES: biostudies-other
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Project description:1. The pyruvate kinases of the desert locust fat body and flight muscle were partially purified by ammonium sulphate fractionation. 2. The fat-body enzyme is allosterically activated by very low (1mum) concentrations of fructose 1,6-diphosphate, whereas the flight-muscle enzyme is unaffected by this metabolite at physiological pH. 3. Flight-muscle pyruvate kinase is activated by preincubation at 25 degrees for 5min., whereas the fat-body enzyme is unaffected by such treatment. 4. Both enzymes require 1-2mm-ADP for maximal activity and are inhibited at higher concentrations. With the fat-body enzyme inhibition by ADP is prevented by the presence of fructose 1,6-diphosphate. 5. Both enzymes are inhibited by ATP, half-maximal inhibition occurring at about 5mm-ATP. With the fat-body enzyme ATP inhibition can be reversed by fructose 1,6-diphosphate. 6. The fat-body enzyme exhibits maximal activity at about pH7.2 and the activity decreases rapidly above this pH. This inactivation at high pH is not observed in the presence of fructose 1,6-diphosphate, i.e. maximum stimulating effects of fructose 1,6-diphosphate are observed at high pH. The flight-muscle enzyme exhibits two optima, one at about pH7.2 as with the fat-body enzyme and the other at about pH8.5. Stimulation of the enzyme activity by fructose 1,6-diphosphate was observed at pH8.5 and above.
| S-EPMC1187519 | biostudies-other
Project description:Background: Hypoxia can affect aerobic organisms profoundly. Biological responses to extreme hypoxia have been well studied. However, it is not well characterized how living organisms respond to mild hypoxia, and how they distinguish different levels of hypoxia. Results: We examined the transcriptional responses of locusts using microarrays to reveal their strategies to cope with mild hypoxia. Mitochondrial activities were systemically suppressed, mainly involving energy production and mitochondrial biogenesis. The functions of endoplasmic reticulum were activated to clear the dysfunctional proteins and rescue newly synthesized proteins. Glucose in cytosol was shunted from glycolysis to pentose phosphate pathway probably to tackle the oxidative stress by enhancing the production of reductive forces. Conclusions: Locusts’ responses to mild hypoxia differ from that to severe hypoxia . In severe hypoxia, glucose resources are shunted to glycolysis to produce ATP and tackle energy crisis; however, in mild hypoxia, they are diverted to produce reductive forces and deal with oxidative stress. Locusts are capable of distinguishing different levels of hypoxia and initiating proper defenses.
2012-12-12 | GSE33898 | GEO
Project description:Background: Hypoxia can affect aerobic organisms profoundly. Biological responses to extreme hypoxia have been well studied. However, it is not well characterized how living organisms respond to mild hypoxia, and how they distinguish different levels of hypoxia. Results: We examined the transcriptional responses of locusts using microarrays to reveal their strategies to cope with mild hypoxia. Mitochondrial activities were systemically suppressed, mainly involving energy production and mitochondrial biogenesis. The functions of endoplasmic reticulum were activated to clear the dysfunctional proteins and rescue newly synthesized proteins. Glucose in cytosol was shunted from glycolysis to pentose phosphate pathway probably to tackle the oxidative stress by enhancing the production of reductive forces. Conclusions: LocustsM-bM-^@M-^Y responses to mild hypoxia differ from that to severe hypoxia . In severe hypoxia, glucose resources are shunted to glycolysis to produce ATP and tackle energy crisis; however, in mild hypoxia, they are diverted to produce reductive forces and deal with oxidative stress. Locusts are capable of distinguishing different levels of hypoxia and initiating proper defenses. Simulated 4km altitude hypoxia treatment vs. normoxia control;direct comparison on 6 separate microarrays; each microarray compares one biological replicate of treatment and control; each biological replicate contains 10 individuals
2012-12-12 | E-GEOD-33898 | biostudies-arrayexpress
Project description:1. Glycogen phosphorylase of locust fat-body was partially purified by differential centrifugation and dissociation from glycogen particles at two pH values. 2. Optimum activity was obtained at pH6.6-6.7. 3. The calculated apparent K(m) values for glycogen and glucose 1-phosphate were 0.08% and 10-13mm respectively. 4. 5'-AMP activated in the range 5mum-1mm. 5. Glucose 6-phosphate is a competitive inhibitor for the substrate glucose 1-phosphate (K(i)=1.7mm). 5'-AMP abolishes this inhibition. Glucose weakly inhibits (K(i)=25-30mm), but trehalose does not inhibit even at 100mm. 6. It is suggested that glucose 6-phosphate is a major regulator of glycogen phosphorylase activity in locust fat-body.
| S-EPMC1165786 | biostudies-other
Project description:Concentrations of glycolytic intermediates, amino acids and possible regulator substances were measured in extracts from locust thoracic muscles perfused under different conditions. The conversion of [(14)C]glucose into intermediates and CO(2) by muscle preparations was also followed. When muscles perfused with glucose were made anaerobic changes in metabolite concentrations occurred that could be accounted for by an activation of phosphofructokinase and pyruvate kinase. When butyrate and glucose were present in the perfusion medium the rate of glycolytic flux was lower than with glucose alone, and the aldolase reaction appeared to be inhibited. When butyrate alone was supplied to the muscle the concentrations of most glycolytic intermediates were similar to those found when glucose was supplied. Iodoacetate caused changes in concentrations of intermediates that appeared to result from inhibition of glyceraldehyde 3-phosphate dehydrogenase. Fluoroacetate-poisoned muscles showed a high citrate concentration, but no obvious site of inhibition by citrate was apparent in the glycolytic pathway. Mechanisms for control of glycolysis in locust flight muscle are discussed and related to the known properties of isolated enzymes. It is proposed that trehalase, hexokinase, phosphofructokinase, aldolase, and pyruvate kinase may be control enzymes in this tissue.
| S-EPMC1174560 | biostudies-other
Project description:Background: Responses to hypoxia have been investigated in many species; however, comparative study between conspecific geographical populations in different altitude regions is rare, especially for invertebrates . The migratory locust, Locusta migratoria, is widely distributed both on high-altitude Tibetan Plateau (TP) and on low-altitude North China Plain (NP). TP locusts have inhabited Tibetan Plateau since Quaternary glaciations events and thus probably have evolved superior capacity to deal with hypoxia. Results: Here we compared the hypoxic responses of TP and NP locusts from morphological, behavioral and physiological perspectives. We found that TP locusts were more tolerant of extreme hypoxia than NP locusts, with a lower proportion exhibiting stupor, a faster recovery time, and higher respiration rates. We compared the transcriptional profiles of field TP and NP locusts and found that their differences were possibly attributed to a combination of multiple factors, e.g. oxygen, UV radiation, temperature and nutrition. To evaluate why TP locusts respond to extreme hypoxia differently from NP locusts, we subjected them to extreme hypoxia and compared their transcriptional responses. We found that the aerobic metabolism was more active in TP locusts than in NP locusts. RNAi disruption of PDHE1b, an entry gene from glycolysis to TCA cycle, increased the ratio of stupor in Tibetan locusts and decreased the ATP content of Tibetan locusts in hypoxia, confirming the significant importance of this metabolic branch for TP locusts to conquer hypoxia. Conclusions: Here we show that TP locusts are better tolerant of hypoxia than NP locusts and the better capacity to modulate primary metabolism in TP locusts contributes to their superior tolerance of hypoxia compared to NP locusts.
2013-12-24 | GSE43327 | GEO
Project description:Background: Responses to hypoxia have been investigated in many species; however, comparative study between conspecific geographical populations in different altitude regions is rare, especially for invertebrates . The migratory locust, Locusta migratoria, is widely distributed both on high-altitude Tibetan Plateau (TP) and on low-altitude North China Plain (NP). TP locusts have inhabited Tibetan Plateau since Quaternary glaciations events and thus probably have evolved superior capacity to deal with hypoxia. Results: Here we compared the hypoxic responses of TP and NP locusts from morphological, behavioral and physiological perspectives. We found that TP locusts were more tolerant of extreme hypoxia than NP locusts, with a lower proportion exhibiting stupor, a faster recovery time, and higher respiration rates. We compared the transcriptional profiles of field TP and NP locusts and found that their differences were possibly attributed to a combination of multiple factors, e.g. oxygen, UV radiation, temperature and nutrition. To evaluate why TP locusts respond to extreme hypoxia differently from NP locusts, we subjected them to extreme hypoxia and compared their transcriptional responses. We found that the aerobic metabolism was more active in TP locusts than in NP locusts. RNAi disruption of PDHE1b, an entry gene from glycolysis to TCA cycle, increased the ratio of stupor in Tibetan locusts and decreased the ATP content of Tibetan locusts in hypoxia, confirming the significant importance of this metabolic branch for TP locusts to conquer hypoxia. Conclusions: Here we show that TP locusts are better tolerant of hypoxia than NP locusts and the better capacity to modulate primary metabolism in TP locusts contributes to their superior tolerance of hypoxia compared to NP locusts. FIELD POPULATION: TP locusts vs. NP locusts;direct comparison on 6 separate microarrays; each microarray compares one biological replicate; each biological replicate contains 10 individuals. LAB POPULATION: hypoxia-treated TP locusts vs TP locusts in normoxia; hypoxia-treated NP locusts vs NP locusts in normoxia; direct comparison on 6 separate microarrays; each microarray compares one biological replicate; each biological replicate contains 10 individuals.
2013-12-24 | E-GEOD-43327 | biostudies-arrayexpress
Project description:The involvement of associative learning cues has been demonstrated in several stages of feeding and food selection. Short neuropeptide F (sNPF), an insect neuropeptide whose effects on feeding behavior have previously been well established, may be one of the factors bridging feeding and learning behavior. Recently, it was shown in Drosophila melanogaster that the targeted reduction of Drome-sNPF transcript levels significantly reduced sugar-rewarded olfactory memory. While Drosophila mainly relies on olfactory perception in its food searching behavior, locust foraging behavior is likely to be more visually orientated. Furthermore, a feeding-dependent regulation of Schgr-sNPF transcript levels has previously been observed in the optic lobes of the locust brain, suggesting a possible involvement in visual perception of food and visual associative memory in this insect species. In this study, we describe the development of a robust and reproducible assay allowing visual associative memory to be studied in the desert locust, Schistocerca gregaria. Furthermore, we performed an exploratory series of experiments, studying the role of Schgr-sNPF in this complex process.
| S-EPMC4553487 | biostudies-literature
Project description:A maternal high-fat (HF) diet during pregnancy can lead to metabolic compromise, such as insulin resistance in adult offspring. Skeletal muscle mitochondrial dysfunction is one mechanism contributing to metabolic impairments in insulin resistant states. Therefore, the present study aimed to investigate whether mitochondrial dysfunction is evident in metabolically compromised offspring born to HF-fed dams. Sprague-Dawley dams were randomly assigned to receive a purified control diet (CD; 10% kcal from fat) or a high fat diet (HFD; 45% kcal from fat) for 10 days prior to mating, throughout pregnancy and during lactation. From weaning, all male offspring received a standard chow diet and soleus muscle was collected at day 150. Expression of the mitochondrial transcription factors nuclear respiratory factor-1 (NRF1) and mitochondrial transcription factor A (mtTFA) were downregulated in HF offspring. Furthermore, genes encoding the mitochondrial electron transport system (ETS) respiratory complex subunits were suppressed in HF offspring. Moreover, protein expression of the complex I subunit, NDUFB8, was downregulated in HF offspring (36%), which was paralleled by decreased maximal catalytic linked activity of complex I and III (40%). Together, these results indicate that exposure to a maternal HF diet during development may elicit lifelong mitochondrial alterations in offspring skeletal muscle.
| S-EPMC5114294 | biostudies-literature
Project description:DNA methylation is a widely conserved epigenetic modification that is established and maintained by the cooperative activity of DNA methyltransferases. While the complement of DNA methyltransferase genes can vary substantially between animal species, whole-genome methylation analyses have suggested that major features of animal methylomes are widely conserved. We have now used genome-scale bisulfite sequencing to analyze the methylome of the desert locust, Schistocerca gregaria, which represents an economically important pest with a high degree of phenotypic plasticity. Interestingly, in this system, DNA methylation appears to be both established and maintained by Dnmt1 methyltransferases, which distinguishes locusts from most other known organisms. Our results indicate that the S. gregaria methylome shares preferential methylation of CpG dinucleotides and exons with other animal methylomes. In contrast to other invertebrates, however, overall methylation levels were substantially higher and a significant fraction of transposons was methylated. Additionally, genes were densely methylated in a pronounced bimodal pattern, suggesting a role for DNA methylation in the regulation of locust gene expression. Altogether, our results uncover a unique pattern of genome methylation in locusts and also suggest that animal methylomes may be more diverse than previously thought.
2013-05-03 | GSE41214 | GEO