67 research outputs found
Hepatic lipogenesis gene expression in two experimental egg-laying lines divergently selected on residual food consumption
Two Rhode Island Red egg-laying lines have been divergently selected on residual food intake (low intake R- line, high intake R+ line) for 19 generations. In addition to direct response, correlated responses have altered several other traits such as carcass adiposity and lipid contents of several tissues, the R+ animals being leaner than the R- ones. In a search for the biological origin of the differences observed in fat deposit, the hepatic mRNA amounts of genes involved in lipid metabolism were investigated. No difference was found between lines for mRNA levels of ATP citrate-lyase, acetyl-CoA carboxylase, fatty acid synthase, malic enzyme and CCAAT/enhancer binding protein α, a transcription factor acting on several lipogenesis genes. The genes coding for stearoyl-CoA desaturase and apolipoprotein A1 displayed significantly lower mRNA levels in the R+ cockerels compared to the R-. All together these mRNA levels explained 40% of the overall variability of abdominal adipose tissue weight, suggesting an important role of both genes in the fatness variability
Several dystrophin-glycoprotein complex members are present in crude surface membranes but they are sodium dodecyl sulphate invisible in KCl-washed microsomes from mdx mouse muscle.
International audienceThe dystrophin-glycoprotein complex (DGC) is a large trans-sarcolemmal complex that provides a linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. In skeletal muscle, it consists of the dystroglycan, sarcoglycan and cytoplasmic complexes, with dystrophin forming the core protein. The DGC has been described as being absent or greatly reduced in dystrophin-deficient muscles, and this lack is considered to be involved in the dystrophic phenotype. Such a decrease in the DGC content was observed in dystrophin-deficient muscle from humans with muscular dystrophy and in mice with X-linked muscular dystrophy (mdx mice). These deficits were observed in total muscle homogenates and in partially membrane-purified muscle fractions, the so-called KCl-washed microsomes. Here, we report that most of the proteins of the DGC are actually present at normal levels in the mdx mouse muscle plasma membrane. The proteins are detected in dystrophic animal muscles when the immunoblot assay is performed with crude surface membrane fractions instead of the usually employed KCl-washed microsomes. We propose that these proteins form SDS-insoluble membrane complexes when dystrophin is absent
Messenger RNA levels and transcription rates of hepatic lipogenesis genes in genetically lean and fat chickens
Levels of body fat content in commercial meat chickens have prompted research in order to control the development of this trait. Based on experimentally selected divergent lean and fat lines, many studies have shown that liver metabolism has a major role in the fatness variability. In order to identify which genes are involved in this variability, we investigated the expression of several genes implicated in the hepatic lipid metabolism. The studied genes code for enzymes of fatty acid synthesis [ATP citrate-lyase (ACL), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), malic enzyme (ME), stearoyl-CoA desaturase (SCD1)], for an apolipoprotein [apolipoprotein A1 (APOA1)], and for the CCAAT/enhancer binding protein α (C/EBPα), which is a transcription factor implied in the regulation of several genes of lipid metabolism. The results show that the fat-line chickens display significantly higher hepatic transcription rates and mRNA levels than the lean-line chickens for the ACL, ME and APOA1 genes. This suggests that these genes could be responsible for the phenotypic fatness variability
The biocontrol bacterium Pseudomonas fluorescens Pf29Arp strain affects the pathogenesis-related gene expression of the take-all fungus Gaeumannomyces graminis var. tritici on wheat roots
The main effects of antagonistic rhizobacteria on plant pathogenic fungi are antibiosis, fungistasis or an indirect constraint through the induction of a plant defence response. To explore different biocontrol mechanisms, an in vitro confrontation assay was conducted with the rhizobacterium Pseudomonas fluorescens Pf29Arp as a biocontrol agent of the fungus Gaeumannomyces graminis var. tritici (Ggt) on wheat roots. In parallel with the assessment of disease extension, together with the bacterial and fungal root colonization rates, the transcript levels of candidate fungal pathogenicity and plant-induced genes were monitored during the 10-day infection process. The bacterial inoculation of wheat roots with the Pf29Arp strain reduced the development of Ggt-induced disease expressed as attack frequency and necrosis length. The growth rates of Ggt and Pf29Arp, monitored through quantitative polymerase chain reaction of DNA amounts with a part of the Ggt 18S rDNA gene and a specific Pf29Arp strain detection probe, respectively, increased throughout the interactions. Bacterial antagonism and colonization had no significant effect on root colonization by Ggt. The expression of fungal and plant genes was quantified in planta by quantitative reverse transcription-polymerase chain reaction during the interactions thanks to the design of specific primers and an innovative universal reference system. During the early stages of the tripartite interaction, several of the fungal genes assayed were down-regulated by Pf29Arp, including two laccases, a ÎČ-1,3-exoglucanase and a mitogen-activated protein kinase. The plant host glutathione-S-transferase gene was induced by Ggt alone and up-regulated by Pf29Arp bacteria in interaction with the pathogen. We conclude that Pf29Arp antagonism acts through the alteration of fungal pathogenesis and probably through the activation of host defences
Etude de la réponse neuronale dans un modÚle d'asphyxie cérébrale chez le rat nouveau-né (influence d'une hyperbilirubinémie associée)
L'hypoxie cĂ©rĂ©brale, par sa frĂ©quence et ses effets dĂ©lĂ©tĂšres, demeure un important facteur de risque en pĂ©riode pĂ©rinatale. Les effets d'une hypoxie transitoire ont Ă©tĂ© Ă©valuĂ©s Ă un stade oĂč le cerveau est trĂšs immature lorsque sa plasticitĂ© est optimale. Des rats de 1 jour ont Ă©tĂ© exposĂ©s pendant 20 mn, Ă 100% d'azote. Les lĂ©sions cĂ©rĂ©brales ont Ă©tĂ© recherchĂ©es dans diffĂ©rentes structures par morphomĂ©trie et comptage cellulaire. Les caractĂ©ristiques de la mort cellulaire ont Ă©tĂ© Ă©valuĂ©es par analyse de la morphologie nuclĂ©aire, la fragmentation d'ADN et par l'expression immunohistochimique de protĂ©ines spĂ©cifiques. Une exploration en IRM de diffusion et la mesure rĂ©gionale de l'activitĂ© de la cytochrome oxydase ont Ă©tĂ© utilisĂ©es en vue d'une approche plus fonctionnelle. Les lĂ©sions cĂ©rĂ©brales sont apparues au 4Ăšme jour aprĂšs rĂ©oxygĂ©nation et Ă©taient d'abord associĂ©es aux manifestations d'une nĂ©crose. Le maximum des dommages est atteint vers 6- 7Ăšme jours, avec un pic d' apoptose reflĂ©tĂ© par la condensation et la fragmentation de l' ADN ainsi que la surexpression de protĂ©ines pro-apoptotiques telles que p53, Dax et la caspase 3. Ces caractĂ©ristiques sont trĂšs proches de l'apoptose physiologique observĂ©e dans le cerveau de rat nouveau-nĂ©. Par la suite, une apparente rĂ©cupĂ©ration morphologique a Ă©tĂ© mise en Ă©vidence, tandis que des dĂ©ficits fonctionnels persistaient Ă long-terme. Le but ultime de ces Ă©tudes Ă©tant de contribuer au dĂ©veloppement de nouvelles stratĂ©gies de neuroprotection, l'influence d'un conditionnement par 10 mn d'hypoxie rĂ©alisĂ©e 6 heures avant l'exposition habituelle ainsi que l'effet d'une hypothermie Ă 26ÊżC ont Ă©tĂ© testĂ©s. Les rĂ©sultats ont montrĂ© une protection totale des neurones, le conditionnement Ă©tant spĂ©cifiquement associĂ© Ă une surexpression de protĂ©ines de survie telles que Dcl-2. Par ailleurs, un prĂ©traitement par un antagoniste des rĂ©cepteurs NMDA, le MK801, a seulement permis de retarder l'apparition des lĂ©sions. La sensibilitĂ© Ă l'hypoxie Ă©tant dĂ©pendante de l'Ă©tat maturationnel du cerveau, une Ă©tude a Ă©tĂ© entreprise sur des animaux ĂągĂ©s de 7 jours, Les rĂ©sultats ont montrĂ© que les dommages cĂ©rĂ©braux Ă©taient plus importants et plus prĂ©coces que dans le modĂšle prĂ©cĂ©dent, et qu'ils Ă©taient la consĂ©quence d'un processus nĂ©crotique. Dans ces conditions, le MK801 Ă©tait capable de protĂ©ger les neurones. Un accident hypoxique cĂ©rĂ©bral peut ĂȘtre associĂ© Ă une hyperbilirubinĂ©mie, une situation frĂ©quemment rencontrĂ©e en nĂ©onatologie. Une injection intrapĂ©ritonĂ©ale de bilirubine chez le rat de 1 jour, associĂ©e ou non Ă une agression hypoxique, a seulement provoquĂ© un ictĂšre physiologique sans rĂ©percussions cĂ©rĂ©brales. Ce modĂšle in vivo n'ayant pas permis l'induction d'un ictĂšre nuclĂ©aire, une statĂ©gie in vitro a Ă©tĂ© dĂ©veloppĂ©e. Sur un modĂšle de culture de neurones issus d'embryons de rats de 14 jours, les effets de la bilirubine non conjuguĂ©e ont Ă©tĂ© Ă©valuĂ©s sur la viabilitĂ© cellulaire, le mĂ©tabolisme Ă©nergĂ©tique et la synthĂšse protĂ©ique. La bilirubine a induit une mort neuronale retardĂ©e qui peut ĂȘtre Ă©vitĂ©e en prĂ©sence d'un inhibiteur de la synthĂšse protĂ©ique, la cycloheximide, et prĂ©sente les caractĂ©ristiques de l'apoptose. Enfin, l'association de l'hypoxie Ă la bilirubine a cumulĂ© les effets dĂ©lĂ©tĂšres sur les neurones in vitro, et l'utilisation d'inhibiteurs sĂ©lectifs des rĂ©cepteurs du glutamate suggĂšre que la neurotoxicitĂ© de la bilirubine est mĂ©diĂ©e par les rĂ©cepteurs NMDA.NANCY1-SCD Pharmacie-Odontologie (543952101) / SudocSudocFranceF
Genetic evidence for differentiation of Ggt populations into two major clades
International audienc
Ggt genetic diversity and development of detection method to test the competition between strains on wheat roots
International audienc
The biocontrol bacterium Pseudomonas fluoresens Pf29Arp strain affects the pathogenesis-related gene expression of the take-all fungus Gaeumannomyces graminis var. tritici on wheat roots
International audienceAntagonistic rhizobacteria can act on plant pathogenic fungi through antibiosis, fungistasis, or induction of a plant defense response. To explore different biocontrol mechanisms, an in vitro confrontation assay was conducted with the rhizobacterium Pseudomonas fluorescens Pf29Arp as a biocontrol agent of the fungus Gaeumannomyces graminis var. tritici (Ggt) on wheat roots. During the 10-day infection process, the disease extension, the bacterial and fungal root colonization rates, and the transcript levels of candidate fungal pathogenicity genes were monitored. The development of the Ggt-induced disease (attack frequency and necrosis length) was reduced in Pf29Arp-inoculated wheat roots. Throughout the interactions, the growth rates of Pf29Arp increased and the bacterial antagonism and colonization had no significant effect on root colonization by Ggt. The expression of fungal genes was quantified in planta by quantitative reverse transcription-polymerase chain reaction and an innovative universal reference system. During the early stages of the tripartite interaction, several of the fungal genes assayed were down-regulated by Pf29Arp, including two laccases, a ÎČ-1, 3-exoglucanase, and a mitogen-activated protein kinase. We conclude that Pf29Arp antagonism acts through the alteration of fungal pathogenesis
Messenger RNA levels and transcription rates of hepatic lipogenesis genes in genetically lean and fat chickens
Levels of body fat content in commercial meat chickens have prompted
research in order to control the development of this trait. Based on
experimentally selected divergent lean and fat lines, many studies
have shown that liver metabolism has a major role in the fatness
variability. In order to identify which genes are involved in this
variability, we investigated the expression of several genes implicated
in the hepatic lipid metabolism. The studied genes code for enzymes of
fatty acid synthesis [ATP citrate-lyase (ACL), acetyl-CoA carboxylase (ACC),
fatty acid synthase (FAS), malic enzyme (ME), stearoyl-CoA desaturase
(SCD1)], for an apolipoprotein [apolipoprotein A1 (APOA1)], and for
the CCAAT/enhancer binding protein (C/EBP), which is
a transcription factor implied in the regulation of several genes of
lipid metabolism. The results show that the fat-line chickens display
significantly higher hepatic transcription rates and mRNA levels than
the lean-line chickens for the ACL, ME and APOA1 genes. This suggests
that these genes could be responsible for the phenotypic fatness variability.Niveaux d'ARNm et taux de transcription hépatiques de gÚnes de la
lipogénÚse chez des poulets génétiquement gras et maigres.
L'engraissement excessif du poulet de chair a conduit à développer des
recherches afin de maßtriser ce caractÚre défavorable. De
nombreuses études, effectuées sur des lignées expérimentales de poulets
gras et maigres obtenues par sélection divergente, ont montré que le
métabolisme hépatique joue un rÎle majeur dans la variabilité de
l'état d'engraissement. Dans le but d'identifier les gÚnes impliqués
dans cette variabilité, le niveau d'expression hépatique de différents
gÚnes impliqués dans le métabolisme des lipides a été analysé. Les gÚnes
étudiés codent pour des enzymes de la synthÚse des acides gras
[ATP citrate-lyase (ACL), acétyl-CoA carboxylase (ACC), synthase des
acides gras (FAS), enzyme malique (ME), stéaroyl-CoA désaturase (SCD1)],
pour une apolipoprotéine [apolipoprotéine A1 (APOA1)], et pour C/EBP
(CCAAT/enhancer binding protein ), un facteur de transcription
régulant plusieurs gÚnes du métabolisme des lipides. Les résultats montrent
que les poulets de la lignée grasse présentent des taux de transcription
et des niveaux de messagers hépatiques des gÚnes ACL, EM et APOA1
significativement plus élevés que ceux de la lignée maigre. Ce résultat
suggĂšre que ces gĂšnes pourraient ĂȘtre responsables de la variabilitĂ©
d'engraissement observée
- âŠ