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81.
Glucose-6 phosphatase (G6Pase), a key enzyme of glucose homeostasis, catalyses the hydrolysis of glucose-6 phosphate (G6P) to glucose and inorganic phosphate. A deficiency in G6Pase activity causes type 1 glycogen storage disease (GSD-1), mainly characterised by hypoglycaemia. Genetic analyses of the two forms of this rare disease have shown that the G6Pase system consists of two proteins, a catalytic subunit (G6PC) responsible for GSD-1a, and a G6P translocase (G6PT), responsible for GSD-1b. However, since their identification, few investigations concerning their structural relationship have been made. In this study, we investigated the localisation and membrane organisation of the G6Pase complex. To this aim, we developed chimera proteins by adding a fluorescent protein to the C-terminal ends of both subunits. The G6PC and G6PT fluorescent chimeras were both addressed to perinuclear membranes as previously suggested, but also to vesicles throughout the cytoplasm. We demonstrated that both proteins strongly colocalised in perinuclear membranes. Then, we studied G6PT organisation in the membrane. We highlighted FRET between the labelled C and N termini of G6PT. The intramolecular FRET of this G6PT chimera was 27%. The coexpression of unlabelled G6PC did not modify this FRET intensity. Finally, the chimera constructs generated in this work enabled us for the first time to analyze the relationship between GSD-1 mutations and the intracellular localisation of both G6Pase subunits. We showed that GSD1 mutations did neither alter the G6PC or G6PT chimera localisation, nor the interaction between G6PT termini. In conclusion, our results provide novel information on the intracellular distribution and organisation of the G6Pase complex. 相似文献
82.
Achard ME Stafford SL Bokil NJ Chartres J Bernhardt PV Schembri MA Sweet MJ McEwan AG 《The Biochemical journal》2012,444(1):51-57
The movement of key transition metal ions is recognized to be of critical importance in the interaction between macrophages and intracellular pathogens. The present study investigated the role of copper in mouse macrophage responses to Salmonella enterica sv. Typhimurium. The copper chelator BCS (bathocuproinedisulfonic acid, disodium salt) increased intracellular survival of S. Typhimurium within primary mouse BMM (bone-marrow-derived macrophages) at 24 h post-infection, implying that copper contributed to effective host defence against this pathogen. Infection of BMM with S. Typhimurium or treatment with the TLR (Toll-like receptor) 4 ligand LPS (lipopolysaccharide) induced the expression of several genes encoding proteins involved in copper transport [Ctr (copper transporter) 1, Ctr2 and Atp7a (copper-transporting ATPase 1)], as well as the multi-copper oxidase Cp (caeruloplasmin). Both LPS and infection with S. Typhimurium triggered copper accumulation within punctate intracellular vesicles (copper 'hot spots') in BMM as indicated by the fluorescent reporter CS1 (copper sensor 1). These copper hot spots peaked in their accumulation at approximately 18 h post-stimulation and were dependent on copper uptake into cells. Localization studies indicated that the copper hot spots were in discrete vesicles distinct from Salmonella containing vacuoles and lysosomes. We propose that copper hot spot formation contributes to antimicrobial responses against professional intracellular bacterial pathogens. 相似文献
83.
Genetics of canine olfaction and receptor diversity 总被引:1,自引:0,他引:1
Olfaction is a particularly important sense in the dog. Humans selected for this capacity during the domestication process, and selection has continued to be employed to enhance this ability. In this review we first describe the different olfactory systems that exist and the different odorant receptors that are expressed in those systems. We then focus on the dog olfactory receptors by describing the olfactory receptor gene repertoire and its polymorphisms. Finally, we discuss the different uses of dog olfaction and the questions that still need to be studied. 相似文献
84.
Zhang C Norris-Caneda KH Rottmann WH Gulledge JE Chang S Kwan BY Thomas AM Mandel LC Kothera RT Victor AD Pearson L Hinchee MA 《Plant physiology》2012,159(4):1319-1334
Pollen elimination provides an effective containment method to reduce direct gene flow from transgenic trees to their wild relatives. Until now, only limited success has been achieved in controlling pollen production in trees. A pine (Pinus radiata) male cone-specific promoter, PrMC2, was used to drive modified barnase coding sequences (barnaseH102E, barnaseK27A, and barnaseE73G) in order to determine their effectiveness in pollen ablation. The expression cassette PrMC2-barnaseH102E was found to efficiently ablate pollen in tobacco (Nicotiana tabacum), pine, and Eucalyptus (spp.). Large-scale and multiple-year field tests demonstrated that complete prevention of pollen production was achieved in greater than 95% of independently transformed lines of pine and Eucalyptus (spp.) that contained the PrMC2-barnaseH102E expression cassette. A complete pollen control phenotype was achieved in transgenic lines and expressed stably over multiple years, multiple test locations, and when the PrMC2-barnaseH102E cassette was flanked by different genes. The PrMC2-barnaseH102E transgenic pine and Eucalyptus (spp.) trees grew similarly to control trees in all observed attributes except the pollenless phenotype. The ability to achieve the complete control of pollen production in field-grown trees is likely the result of a unique combination of three factors: the male cone/anther specificity of the PrMC2 promoter, the reduced RNase activity of barnaseH102E, and unique features associated with a polyploid tapetum. The field performance of the PrMC2-barnaseH102E in representative angiosperm and gymnosperm trees indicates that this gene can be used to mitigate pollen-mediated gene flow associated with large-scale deployment of transgenic trees. 相似文献
85.
Zerjal T Rousselet A Mhiri C Combes V Madur D Grandbastien MA Charcosset A Tenaillon MI 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(8):1521-1537
Transposable elements are the major component of the maize genome and presumably highly polymorphic yet they have not been
used in population genetics and association analyses. Using the Transposon Display method, we isolated and converted into
PCR-based markers 33 Miniature Inverted Repeat Transposable Elements (MITE) polymorphic insertions. These polymorphisms were
genotyped on a population-based sample of 26 American landraces for a total of 322 plants. Genetic diversity was high and
partitioned within and among landraces. The genetic groups identified using Bayesian clustering were in agreement with published
data based on SNPs and SSRs, indicating that MITE polymorphisms reflect maize genetic history. To explore the contribution
of MITEs to phenotypic variation, we undertook an association mapping approach in a panel of 367 maize lines phenotyped for
26 traits. We found a highly significant association between the marker ZmV1-9, on chromosome 1, and male flowering time. The variance explained by this association is consistent with a flowering delay
of +123 degree-days. This MITE insertion is located at only 289 nucleotides from the 3′ end of a Cytochrome P450-like gene,
a region that was never identified in previous association mapping or QTL surveys. Interestingly, we found (i) a non-synonymous
mutation located in the exon 2 of the gene in strong linkage disequilibrium with the MITE polymorphism, and (ii) a perfect
sequence homology between the MITE sequence and a maize siRNA that could therefore potentially interfere with the expression
of the Cytochrome P450-like gene. Those two observations among others offer exciting perspectives to validate functionally
the role of this region on phenotypic variation. 相似文献
86.
Effects of ocean acidification on learning in coral reef fishes 总被引:2,自引:0,他引:2
Ferrari MC Manassa RP Dixson DL Munday PL McCormick MI Meekan MG Sih A Chivers DP 《PloS one》2012,7(2):e31478
Ocean acidification has the potential to cause dramatic changes in marine ecosystems. Larval damselfish exposed to concentrations of CO(2) predicted to occur in the mid- to late-century show maladaptive responses to predator cues. However, there is considerable variation both within and between species in CO(2) effects, whereby some individuals are unaffected at particular CO(2) concentrations while others show maladaptive responses to predator odour. Our goal was to test whether learning via chemical or visual information would be impaired by ocean acidification and ultimately, whether learning can mitigate the effects of ocean acidification by restoring the appropriate responses of prey to predators. Using two highly efficient and widespread mechanisms for predator learning, we compared the behaviour of pre-settlement damselfish Pomacentrus amboinensis that were exposed to 440 μatm CO(2) (current day levels) or 850 μatm CO(2), a concentration predicted to occur in the ocean before the end of this century. We found that, regardless of the method of learning, damselfish exposed to elevated CO(2) failed to learn to respond appropriately to a common predator, the dottyback, Pseudochromis fuscus. To determine whether the lack of response was due to a failure in learning or rather a short-term shift in trade-offs preventing the fish from displaying overt antipredator responses, we conditioned 440 or 700 μatm-CO(2) fish to learn to recognize a dottyback as a predator using injured conspecific cues, as in Experiment 1. When tested one day post-conditioning, CO(2) exposed fish failed to respond to predator odour. When tested 5 days post-conditioning, CO(2) exposed fish still failed to show an antipredator response to the dottyback odour, despite the fact that both control and CO(2)-treated fish responded to a general risk cue (injured conspecific cues). These results indicate that exposure to CO(2) may alter the cognitive ability of juvenile fish and render learning ineffective. 相似文献
87.
Leach MC Klaus K Miller AL Scotto di Perrotolo M Sotocinal SG Flecknell PA 《PloS one》2012,7(4):e35656
Background
Current behaviour-based pain assessments for laboratory rodents have significant limitations. Assessment of facial expression changes, as a novel means of pain scoring, may overcome some of these limitations. The Mouse Grimace Scale appears to offer a means of assessing post-operative pain in mice that is as effective as manual behavioural-based scoring, without the limitations of such schemes. Effective assessment of post-operative pain is not only critical for animal welfare, but also the validity of science using animal models.Methodology/Principal Findings
This study compared changes in behaviour assessed using both an automated system (“HomeCageScan”) and using manual analysis with changes in facial expressions assessed using the Mouse Grimace Scale (MGS). Mice (n = 6/group) were assessed before and after surgery (scrotal approach vasectomy) and either received saline, meloxicam or bupivacaine. Both the MGS and manual scoring of pain behaviours identified clear differences between the pre and post surgery periods and between those animals receiving analgesia (20 mg/kg meloxicam or 5 mg/kg bupivacaine) or saline post-operatively. Both of these assessments were highly correlated with those showing high MGS scores also exhibiting high frequencies of pain behaviours. Automated behavioural analysis in contrast was only able to detect differences between the pre and post surgery periods.Conclusions
In conclusion, both the Mouse Grimace Scale and manual scoring of pain behaviours are assessing the presence of post-surgical pain, whereas automated behavioural analysis could be detecting surgical stress and/or post-surgical pain. This study suggests that the Mouse Grimace Scale could prove to be a quick and easy means of assessing post-surgical pain, and the efficacy of analgesic treatment in mice that overcomes some of the limitations of behaviour-based assessment schemes. 相似文献88.
Douglas P. Chivers Xiaoxia Zhao Grant E. Brown Tracy A. Marchant Maud C. O. Ferrari 《Evolutionary ecology》2008,22(4):561-574
In a series of experiments, we investigated the effects of food availability and risk frequency on the dynamics of predator-induced
changes in growth and morphology of prey fish using goldfish (Carassius auratus) as our test species. In experiment 1, we fed goldfish high or low food rations and exposed them to either alarm cues from
conspecifics, cues from swordtails or a water control. After 60 days, goldfish in the alarm cue treatment significantly increased
their body depth and body weight but had smaller body length than goldfish exposed to swordtails cues or water, likely reducing
their vulnerability to gape-limited predators. Importantly, food level had an impact on the amplitude of the morphological
changes. In experiment 2, goldfish were exposed to two different frequencies of predation cues or a water control for 50 days.
The cues were either continued or discontinued from day 51 to 100, and all cues were resumed from day 101 to 150. We found
that goldfish exposed to predation cues increased their depth and weight at a faster rate than did the goldfish exposed to
water, and of particular significance was the fact that frequency of risk had an effect on the amplitude of the change. When
the cues were interrupted, the increase in growth rate parameters was reduced to the level of the goldfish exposed to water.
However, when the cues were resumed, the rate increased to match the growth rate of the goldfish that were continuously exposed
to the cues. Finally, we staged encounters between goldfish of differing morphologies and yellow perch (Perca flavescens) and found that deep-bodied goldfish had better survival than the shallow-bodied ones. These experiments illustrate the dynamic
nature of inducible morphological defences. 相似文献
89.
90.
Romestaing C Piquet MA Letexier D Rey B Mourier A Servais S Belouze M Rouleau V Dautresme M Ollivier I Favier R Rigoulet M Duchamp C Sibille B 《American journal of physiology. Endocrinology and metabolism》2008,294(1):E110-E119
Nonalcoholic fatty liver disease (NAFLD) has become common liver disease in Western countries. There is accumulating evidence that mitochondria play a key role in NAFLD. Nevertheless, the mitochondrial consequences of steatohepatitis are still unknown. The bioenergetic changes induced in a methionine- and choline-deficient diet (MCDD) model of steatohepatitis were studied in rats. Liver mitochondria from MCDD rats exhibited a higher rate of oxidative phosphorylation with various substrates, a rise in cytochrome oxidase (COX) activity, and an increased content in cytochrome aa3. This higher oxidative activity was associated with a low efficiency of the oxidative phosphorylation (ATP/O, i.e., number of ATP synthesized/natom O consumed). Addition of a low concentration of cyanide, a specific COX inhibitor, restored the efficiency of mitochondria from MCDD rats back to the control level. Furthermore, the relation between respiratory rate and protonmotive force (in the nonphosphorylating state) was shifted to the left in mitochondria from MCDD rats, with or without cyanide. These results indicated that, in MCDD rats, mitochondrial ATP synthesis efficiency was decreased in relation to both proton pump slipping at the COX level and increased proton leak although the relative contribution of each phenomenon could not be discriminated. MCDD mitochondria also showed a low reactive oxygen species production and a high lipid oxidation potential. We conclude that, in MCDD-fed rats, liver mitochondria exhibit an energy wastage that may contribute to limit steatosis and oxidative stress in this model of steatohepatitis. 相似文献