Effects of aerobic exercise on metabolic syndrome improvement in response to weight reduction

Objective: The objective was to test effects of aerobic exercise training on metabolic syndrome (MetSyn) improvement in response to weight reduction. Research Methods and Procedures: A total of 459 overweight and obese women (age, 49 ± 9 years; BMI, 28 ± 3 kg/m²) were recruited for a baseline examination to test the relationship between cardiorespiratory fitness and metabolic syndrome prevalence; among these, 67 subjects with MetSyn were treated with 14‐week weight‐loss programs, which included low‐calorie diet and aerobic exercise. The MetSyn was defined according to the Examination Committee of Criteria for “Metabolic Syndrome” in Japan. Maximal oxygen uptake (V?o _2max) during a maximal cycling test was measured as an index of cardiorespiratory fitness at baseline and after the intervention. Results: In the baseline examination, age‐ and BMI‐adjusted odds ratios for MetSyn prevalence in the low, middle, and upper thirds of V?o _2max were 1.0 (referent), 0.50 (95% confidence interval, 0.26 to 0.95), and 0.39 (95% confidence interval, 0.14 to 0.96), respectively (linear trend, p = 0.02). The adjusted odds ratios for MetSyn improvement in the two interventions with diet alone and diet plus exercise were 1.0 and 3.68 (95% confidence interval, 1.02 to 17.6; p = 0.04), respectively. Discussion: These results suggest that adding aerobic exercise training to a dietary weight‐reduction program further improves MetSyn (adjusted odds ratio, 3.68) in obese women, compared with diet alone. Further studies on an association between V?o _2max change and MetSyn improvement are needed.     

Age-Associated Different Transcriptome Profiling in Zebrafish and Rats: an Insight into the Diversity of Vertebrate Aging

Marine Biotechnology - Most mammals, including humans, show obvious aging phenotypes, for example, loss of tissue plasticity and sarcopenia. In this regard, fish can be attractive models to study...     

Colour vision in the tropical giant mottled eel Anguilla marmorata as determined by classical conditioning test

Ichthyological Research - The giant mottled eel Anguilla marmorata Quoy & Gaimard is an important aquaculture candidate in eel farming industry. The high economic value of the species leads...     

Activation of group IV cytosolic phospholipase A2 in human eosinophils by phosphoinositide 3-kinase through a mitogen-activated protein kinase-independent pathway

Activation of group IV cytosolic phospholipase A(2) (gIV-PLA(2)) is the essential first step in the synthesis of inflammatory eicosanoids and in integrin-mediated adhesion of leukocytes. Prior investigations have demonstrated that phosphorylation of gIV-PLA(2) results from activation of at least two isoforms of mitogen-activated protein kinase (MAPK). We investigated the potential role of phosphoinositide 3-kinase (PI3K) in the activation of gIV-PLA(2) and the hydrolysis of membrane phosphatidylcholine in fMLP-stimulated human blood eosinophils. Transduction into eosinophils of Deltap85, a dominant negative form of class IA PI3K adaptor subunit, fused to an HIV-TAT protein transduction domain (TAT-Deltap85) concentration dependently inhibited fMLP-stimulated phosphorylation of protein kinase B, a downstream target of PI3K. FMLP caused increased arachidonic acid (AA) release and secretion of leukotriene C(4) (LTC(4)). TAT-Deltap85 and LY294002, a PI3K inhibitor, blocked the phosphorylation of gIV-PLA(2) at Ser(505) caused by fMLP, thus inhibiting gIV-PLA(2) hydrolysis and production of AA and LTC(4) in eosinophils. FMLP also caused extracellular signal-related kinases 1 and 2 and p38 MAPK phosphorylation in eosinophils; however, neither phosphorylation of extracellular signal-related kinases 1 and 2 nor p38 was inhibited by TAT-Deltap85 or LY294002. Inhibition of 1) p70 S6 kinase by rapamycin, 2) protein kinase B by Akt inhibitor, or 3) protein kinase C by Ro-31-8220, the potential downstream targets of PI3K for activation of gIV-PLA(2), had no effect on AA release or LTC(4) secretion caused by fMLP. We find that PI3K is required for gIV-PLA(2) activation and hydrolytic production of AA in activated eosinophils. Our data suggest that this essential PI3K independently activates gIV-PLA(2) through a pathway that does not involve MAPK.     

Redox properties of quinohemoprotein amine dehydrogenase from Paracoccus denitrificans

Paracoccus denitrificans produces two primary enzymes for the amine oxidation, tryptophan-tryptophylquinone (TTQ)-containing methylamine dehydrogenase (MADH) and quinohemoprotein amine dehydrogenase (QH-AmDH). QH-AmDH has a novel cofactor, cysteine tryptophylquinone (CTQ) and two hemes c. In this work, the redox potentials of three redox centers in QH-AmDH were determined by a mediator-assisted continuous-flow column electrolytic spectroelectrochemical technique. Kinetics of the electron transfer from QH-AmDH to three kinds of metalloproteins, amicyanin, cytochrome c(550), and horse heart cytochrome c were examined on the basis of the theory of mediated-bioelectrocatalysis. All these metalloproteins work as a good electron acceptor of QH-AmDH and donate the electron to the terminal oxidase of P. denitrificans, which was revealed by reconstitution of the respiratory chain. These properties are in marked contrast with those of MADH, which shows high specificity to amicyanin. These electron transfer kinetics are discussed in terms of thermodynamics and structural property.     

Direct evidence for two distinct forms of the flavoprotein subunit of human mitochondrial complex II (succinate-ubiquinone reductase)

Succinate-ubiquinone reductase (complex II) is an important enzyme complex in both the tricarboxylic acid cycle and aerobic respiration. A recent study showed that defects in human complex II are associated with cancers as well as mitochondrial diseases. Mutations in the four subunits of human complex II are associated with a wide spectrum of clinical presentations. Such tissue-specific clinical symptoms suggest the presence of multiple isoforms of the subunits, but subunit isoforms have not been previously reported. In the present study, we identified two distinct cDNAs for the human flavoprotein subunit (Fp) from a single individual, and demonstrated expression of these two isoforms in skeletal muscle, liver, brain, heart and kidney. Interestingly, one of the Fp isoforms was encoded as an intronless gene.     

A comparative study on the hydroperoxide and thiol specificity of the glutathione peroxidase family and selenoprotein P

Glutathione peroxidase catalyzes the reduction of hydrogen peroxide and organic hydroperoxide by glutathione and functions in the protection of cells against oxidative damage. Glutathione peroxidase exists in several forms that differ in their primary structure and localization. We have also shown that selenoprotein P exhibits a glutathione peroxidase-like activity (Saito, Y., Hayashi, T., Tanaka, A., Watanabe, Y., Suzuki, M., Saito, E., and Takahashi, K. (1999) J. Biol. Chem. 274, 2866-2871). To understand the physiological significance of the diversity among these enzymes, a comparative study on the peroxide substrate specificity of three types of ubiquitous glutathione peroxidase (cellular glutathione peroxidase, phospholipid hydroperoxide glutathione peroxidase, and extracellular glutathione peroxidase) and of selenoprotein P purified from human origins was done. The specific activities and kinetic parameters against two hydroperoxides (hydrogen peroxide and phosphatidylcholine hydroperoxide) were determined. We next examined the thiol specificity and found that thioredoxin is the preferred electron donor for selenoprotein P. These four enzymes exhibit different peroxide and thiol specificities and collaborate to protect biological molecules from oxidative stress both inside and outside the cells.     

Spectroelectrochemical evaluation of redox potentials of cysteine tryptophylquinone and two hemes c in quinohemoprotein amine dehydrogenase from Paracoccus denitrificans

Quinohemoprotein amine dehydrogenase (QH-AmDH) from Paracoccus denitrificans has a novel cofactor cysteine tryptophylquinone (CTQ) in the smallest gamma subunit and two hemes c in the largest alpha subunit [Datta, S., Mori, Y., Takagi, K., Kawaguchi, K., Chen, Z., Okajima, T., Kuroda, S., Ikeda, T., Kano, K., Tanizawa, K., and Mathews, F. S. (2001) Proc. Natl. Acad. Sci. U.S.A. 98, 14268-14273]. The spectral change of QH-AmDH was assigned to the redox reaction of the hemes c alone. The redox potentials of the two hemes c with His and Met as the second axial ligands, respectively, were determined to be 0.149 and 0.235 V versus SHE at pH 7.0 by a mediator-assisted continuous-flow column electrolytic spectroelectrochemistry (MCES). The monomeric gamma subunit of QH-AmDH was isolated from urea-treated QH-AmDH. The fully oxidized and reduced forms of the gamma subunit exhibited a unique absorption band centered at 380 nm and a shoulder band around 315 nm, respectively, at neutral pH. The two-electron redox potential of CTQ in the isolated gamma subunit was evaluated to be 65 mV at pH 7.0 by MCES. The redox reaction was linked to the two-proton transfer at pH <8.6 and to a single-proton transfer at pH >8.6. The pK(a) value (K(a) being the acid dissociation constant) of 8.6 was assigned to one of the phenolic OH groups of the quinol form. Upon deprotonation, the red shift of the shoulder band was observed. The gamma subunit adsorbed on a glassy carbon electrode, and gave a direct but quasi-reversible electrochemical signal. Intra- and interprotein electron transfers of QH-AmDH are discussed from thermodynamic and structural points of view.