Sex-specific regulation of AMP-activated protein kinase (AMPK) in the Pacific oyster Crassostrea gigas.

The hermaphrodite Pacific oyster Crassostrea gigas displays a high energy allocation to reproduction. We studied the expression of AMP-activated protein kinase (AMPK) during gametogenesis in the gonad and characterized the mRNA sequences of the AMPK subunits: the AMPK alpha mRNA sequence was previously characterized; we identified AMPK beta, AMPK gamma, and mRNAs of putative AMPK-related targets following bioinformatics mining on existing genomic resources. We analyzed the mRNA expression of the AMPK alpha, beta, and gamma subunits in the gonads of male and female oysters through a reproductive cycle, and we quantified the mRNA expression of genes belonging to fatty acid and glucose metabolism.

Regulation of a truncated isoform of AMP-activated protein kinase α (AMPKα) in response to hypoxia in the muscle of Pacific oyster Crassostrea gigas.

AMP-activated protein kinase α (AMPKα) is a key regulator of energy balance in many model species during hypoxia. In a marine bivalve, the Pacific oyster Crassostrea gigas, we analyzed the protein content of adductor muscle in response to hypoxia during 6 h. In both smooth and striated muscles, the amount of full-length AMP-activated protein kinase α (AMPKα) remained unchanged during hypoxia.

In vivo RNA interference of a gonad-specific transforming growth factor-β in the Pacific oyster Crassostrea gigas.

We investigated the role of oyster gonadal TGFβ (og-TGFβ) in the reproduction of Crassostrea gigas, using an in vivo RNA interference approach. We designed double-stranded RNA targeting og-TGFβ, which is specifically expressed in the somatic cells surrounding germ cells in the gonad of both male and female oysters. In vivo injection of this og-TGFβ dsRNA into the gonad led to knock-down phenotypes for both sexes, with significant reduction (77.

Metastasis suppressor NM23-H1 promotes repair of UV-induced DNA damage and suppresses UV-induced melanomagenesis.

Reduced expression of the metastasis suppressor NM23-H1 is associated with aggressive forms of multiple cancers. Here, we establish that NM23-H1 (termed H1 isoform in human, M1 in mouse) and two of its attendant enzymatic activities, the 3'-5' exonuclease and nucleoside diphosphate kinase, are novel participants in the cellular response to UV radiation (UVR)-induced DNA damage. NM23-H1 deficiency compromised the kinetics of repair for total DNA polymerase-blocking lesions and nucleotide excision repair of (6-4) photoproducts in vitro.

Microarray-based identification of gonad transcripts differentially expressed between lines of Pacific oyster selected to be resistant or susceptible to summer mortality.

Summer mortality of the Pacific oyster Crassostrea gigas is the result of a complex interaction between oysters, their environment, and pathogens. Heredity appears to be a major factor determining the sensitivity of oysters to summer mortality, allowing resistant (R) and susceptible (S) lines to be produced. We conducted genome-wide expression profiling of R and S gonads during the 3-month period preceding a summer mortality event, using a cDNA microarray that we designed.

Infrared spectroscopy: a reagent-free method to distinguish Alzheimer's disease patients from normal-aging subjects.

The physiopathogenesis of Alzheimer's disease (AD) is related to various biochemical mechanisms that may be reflected by changes in plasma components. In the current study, Fourier transform-infrared (FT-IR) spectroscopy was used to identify these biochemical variations by monitoring spectral differences in the plasma of 40 AD patients compared with those of 112 control subjects. A hierarchical classification in the whole mid-infrared region allowed a clear separation between AD and controls (C) that was optimized by using a restricted spectral range (1480-1428 cm(-1)).

Combination of a pesticide exposure and a bacterial challenge: in vivo effects on immune response of Pacific oyster, Crassostrea gigas (Thunberg).

To assess the impact of pollution induced by pesticides on Pacific oyster, Crassostrea gigas, health in France, in vivo effects of combined pesticide exposure and bacterial challenge on cell activities and gene expression in hemocytes were tested using flow cytometry and real-time PCR. As a first step, an in vivo model of experimental contamination was developed. Pacific oysters were exposed to a mixture of eight pesticides (atrazine, glyphosate, alachlor, metolachlor, fosetyl-alumimium, terbuthylazine, diuron and carbaryl) at environmentally relevant concentrations over a 7-day period.

Protein kinase CK2 acts as a signal molecule switching between the NDPK-A/AMPK alpha1 complex and NDPK-B.

Previously we elucidated the molecular interaction between the nucleoside diphosphate kinase A (NDPK-A)/AMP-activated protein kinase (AMPK) alpha1 complex, discovering a process we termed "substrate channeling." Here, we investigate the protein-protein interaction of the substrate channeling complex with the pleiotropic protein kinase, CK2 (formerly casein kinase 2). We show that CK2 is part of the NDPK-A/AMPK alpha1 complex under basal (background AMPK activity) conditions, binding directly to each of the complex components independently.

Understanding the molecular basis of the interaction between NDPK-A and AMPK alpha 1.

Nucleoside diphosphate kinase (NDPK) (nm23/awd) belongs to a multifunctional family of highly conserved proteins (approximately 16 to 20 kDa) including two well-characterized isoforms (NDPK-A and -B). NDPK catalyzes the conversion of nucleoside diphosphates to nucleoside triphosphates, regulates a diverse array of cellular events, and can act as a protein histidine kinase. AMP-activated protein kinase (AMPK) is a heterotrimeric protein complex that responds to the cellular energy status by switching off ATP-consuming pathways and switching on ATP-generating pathways when ATP is limiting.

Acute oxidative stress is associated with cell proliferation in the mouse liver.

Oxidative stress is known to produce tissue injury and to activate various signaling pathways. To investigate the molecular events linked to acute oxidative stress in mouse liver, we injected a toxic dose of paraquat. Liver necrosis was first observed, followed by histological marks of cell proliferation.

NDPK-A (but not NDPK-B) and AMPK alpha1 (but not AMPK alpha2) bind the cystic fibrosis transmembrane conductance regulator in epithelial cell membranes.

Cystic fibrosis (CF) results from mutations within the cystic fibrosis transmembrane-conductance regulator (CFTR) protein. The AMP-activated protein kinase (AMPK) is a heterotrimer composed of different isoforms of the alphabetagamma subunits, where the alpha1 catalytic subunit binds CFTR. Nucleoside diphosphate kinase (NDPK, NM23/awd) converts nucleoside diphosphates to nucleoside triphosphates but also acts as a protein kinase.

Expression patterns of nm23 genes during mouse organogenesis.

Nucleoside di-phosphate kinase enzyme (NDPK) isoforms, encoded by the nm23 family of genes, may be involved in various cellular differentiation and proliferation processes. We have therefore analyzed the expression of nm23-M1, -M2, -M3, and -M4 during embryonic mouse development. In situ hybridization data has revealed the differential expression of nm23 mRNA during organogenesis.

Increased lung metastasis in transgenic NM23-Null/SV40 mice with hepatocellular carcinoma.

Background: The metastasis-suppressing role of the NM23 gene in the metastatic spread of solid tumors is still debated. We examined the role of NM23 in tumor development and metastatic dissemination by using transgenic mice that lack mouse NM23 (NM23-M1) in two mouse models of hepatocellular carcinoma (HCC) that recapitulate all steps of tumor progression.

Methods: We induced HCC in mice that contained (NM23-M1(+/+)) or lacked (NM23-M1(-/-)) NM23-M1 by diethylnitrosamine injection or by a crossing scheme that transferred a transgene that leads to liver expression of simian virus 40 large T antigen (ASV mice).

Nm23-M2/NDP kinase B induces endogenous c-myc and nm23-M1/NDP kinase A overexpression in BAF3 cells. Both NDP kinases protect the cells from oxidative stress-induced death.

The nm23 gene family encodes nucleoside diphosphate kinases (NDPKs) which supply the cell with (d)NTPs. The human NDPKB, also known as the PuF protein, binds the c-myc promoter and transactivates the c-myc protooncogene. We have now studied the effects of mouse NDPKA and NDPKB overexpression on endogenous c-myc transactivation in the mouse BAF3 and the rat PC12 cell lines.

Oxidative and antioxidative status in pregnant women with either gestational or type 1 diabetes.

Objectives: To evaluate oxidative and antioxidative status in pregnant diabetic women between 26 and 32 weeks of gestation.

Design And Methods: Free and total malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX), and vitamins A and E were determined in plasma and erythrocytes of 54 pregnant women. Among these, 27 were diabetics with either gestational diabetes mellitus (GDM), sub-group I, or previous insulin-dependent diabetes mellitus (type 1 diabetes), sub-group II.

Differential expression of nm23 genes in adult mouse dorsal root ganglia.

Nm23 has been identified as a gene family encoding different isoforms of nucleoside diphosphate kinase (NDPK). This protein is a key enzyme in nucleotide metabolism and has been shown to play important roles in various cellular functions. In the present study, we have investigated the expression of three isotypes in mouse dorsal root ganglia.