SNP- and haplotype-based genome-wide association studies for growth, carcass, and meat quality traits in a Duroc multigenerational population

Average linkage disequilibrium coefficient (r2) values plotted against intermarker distance for all autosomal chromosomes. (PDF 407 kb

Changes on the Physiological Lactonase Activity of Serum Paraoxonase 1 by a Diet Intervention for Weight Loss in Healthy Overweight and Obese Women

Low caloric diet (LCD) is used for weight loss. Paraoxonase 1 (PON-1) is associated with the antioxidant functions of high-density lipoprotein (HDL). Among limited data on the relationships between obesity and PON-1, there has been no study on the effects of a stand-alone LCD on the physiological lactonase activity of PON-1. We investigated the prospective effects of LCD intervention (2 months) for weight loss on serum PON-1 activities (lactonase, arylesterase [mono-esterase] and tri-esterase) and HDL cholesterol (HDL-C), and their association with low-density lipoprotein cholesterol (LDL-C) in overweight and non-morbidly obese but otherwise healthy women (n = 30; mean age, 50.3 years; mean body mass index [BMI], 28.5 kg/m2). In addition to the data such as BMI, blood pressure, blood glucose and lipids, PON-1 activities were examined between pre- and post-intervention. The intervention reduced all metabolic outcomes, and PON-1 lactonase activity (determined with 5-[thiobutyl]butyrolactone) significantly decreased by 6.1%, paralleled by arylesterase (by 7.3%) and tri-esterase (by 7.8%). In multiple regression analysis, the percent change of PON-1 lactonase was significantly, positively and independently correlated to that of LDL-C (β = 0.51), HDL-C (β = 0.40), and BMI (β = 0.37). Our results showed that the solo diet treatment on weight loss might reduce serum PON-1 lactonase activity with reduced HDL-C and LDL-C. The relationship between the lactonase and LDL-C may be adaptive, plausibly hypothesizing less need for PON-1 activity as an antioxidant property to protect lipoproteins. Further research is needed to confirm this prediction

Water Status of Flower Buds and Leaves as Affected by High Temperature in Heat-Tolerant and Heat-Sensitive Cultivars of Snap Bean (Phaseolus vulgaris L.)

In snap bean {Phaseolus vulgaris L.), flower and pod abscission causes yield reduction under high-temperature conditions. A high temperature enhances transpiration and thus may induce temporal water deficiency in plants in the daytime. The objective of this study was to clarify the effect of a high temperature on the water status of floral organs at their most heat-sensitive stage. We compared the water potential and its components as well as gas exchange between the heat-tolerant cultivar, Haibushi, and heat-sensitive cultivar, Kentucky Wonder, grown under optimal (control) and high-temperature conditions. Haibushi showed higher pollen fertility under high temperature than Kentucky Wonder. Transpiration was enhanced under a high temperature, causing decrease of water potential in leaves and flower buds. The deterioration of water status in floral organs was larger in Kentucky Wonder than in Haibushi. We conclude that temporal deterioration of the water status in flower buds is one of the factors causing pollen damage

Diurnal Change in Water Balance of Heat-Tolerant Snap Bean (Phaseolus vulgaris) Cultivar and Its Association with Growth under High Temperature

A snap bean (Phaseolus vulgaris L.) cultivar Haibushi shows high productivity under high-temperature conditions. Together with intensive radiation, high temperature enhances transpiration and causes water deficit in plants even when they are irrigated enough. To characterize daily change in water balance of the heat-tolerant cultivar, we compared parameters of water balance, dry matter production and pod yield among cultivars. Four snap bean cultivars, Haibushi, Kurodane-Kinugasa, Oregon and Kentucky Wonder, were grown under optimal temperature (spring cropping) and high temperature (summer cropping) condition in the field. The daily water balance and gas exchange rate in the heat-tolerant cultivar Haibushi were compared with those in the heat-sensitive cultivar Kentucky Wonder, grown in 0.02 m2 Wagner pots. In the summer cropping in the field, dry matter production, pod yield, stomatal conductance, photosynthetic rate and transpiration rate were higher in Haibushi and Kurodane-Kinugasa than in the other cultivars. In a glasshouse, the sap flow rate was lower than the transpiration rate in the morning when the transpiration rate rapidly increased in both Haibushi and Kentucky Wonder. In spite of the higher transpiration rate, Haibushi showed a higher sap flow rate and smaller cumulative water loss in the morning than Kentucky Wonder. We conclude that better growth of the heat-tolerant snap bean cultivar Haibushi under high temperature was due to higher photosynthetic rate resulting from higher stomatal conductance during the daytime, which had a higher water uptake rate

Caffeine Affects Myotube Size As Well As Regulates Protein Degradation and Protein Synthesis Pathways in C2C12 Skeletal Muscle Cells

[Background]: Caffeine has been implicated in energy metabolism regulation in skeletal muscle. However, it is unclear whether caffeine affects the regulation of skeletal muscle size. In the present study, we evaluated the effect of caffeine on muscle size as well as accompanied changes of ubiquitin–proteasome system and Akt/mammalian target of rapamycin (mTOR)/p70 s6 kinase (p70S6K) signaling. [Methods]: Differentiated C2C12 myotubes were incubated with caffeine (0, 0.1, 1.0, 3.0 mM) for 24 hours. We then estimated the protein content, myotube diameter, and the expression levels of muscle RING finger 1 (MuRF1) messenger RNA (mRNA), atrogin-1/muscle atrophy F-box (MAFbx) mRNA, K48-linked polyubiquitin, phosphorylated 5′-AMP-activated protein kinase (AMPK) α Thr172, 72-kDa heat shock protein (HSP72), HSP72 mRNA, inhibitor κBα (IκBα), phosphorylated forkhead box class O3a (FoxO3a) Ser253, myogenin mRNA, microRNA (miR)-23a, phosphorylated Akt Ser473, and phosphorylated p70S6K Thr389. [Results]: Protein content and myotube diameter were lower in myotubes treated with caffeine (≥1 mM) compared with untreated cells. The expression levels of MuRF1 and atrogin-1/MAFbx mRNA and K48-linked polyubiquitin were increased by caffeine treatment. However, phosphorylated AMPKα Thr172, HSP72 protein and mRNA, IκBα, phosphorylated FoxO3a Ser253, and miR-23a expression were not affected by caffeine treatment. Myogenin mRNA expression was upregulated in response to caffeine treatment. The expressions of phosphorylated Akt Ser473 and p70S6K Thr389 were suppressed by caffeine. [Conclusions]: Caffeine might affect muscle size by stimulating ubiquitin–proteasome system and inhibiting Akt/mTOR/p70S6K signaling, partly through an AMPK-independent mechanism

Involvement of AMPK in regulating slow-twitch muscle atrophy during hindlimb unloading in mice

AMPK is considered to have a role in regulating skeletal muscle mass. However, there are no studies investigating the function of AMPK in modulating skeletal muscle mass during atrophic conditions. In the present study, we investigated the difference in unloading-associated muscle atrophy and molecular functions in response to 2-wk hindlimb suspension between transgenic mice overexpressing the dominant-negative mutant of AMPK (AMPK-DN) and their wild-type (WT) littermates. Male WT (n = 24) and AMPK-DN (n = 24) mice were randomly divided into two groups: an untreated preexperimental control group (n = 12 in each group) and an unloading (n = 12 in each group) group. The relative soleus muscle weight and fiber cross-sectional area to body weight were decreased by ∼30% in WT mice by hindlimb unloading and by ∼20% in AMPK-DN mice. There were no changes in puromycin-labeled protein or Akt/70-kDa ribosomal S6 kinase signaling, the indicators of protein synthesis. The expressions of ubiquitinated proteins and muscle RING finger 1 mRNA and protein, markers of the ubiquitin-proteasome system, were increased by hindlimb unloading in WT mice but not in AMPK-DN mice. The expressions of molecules related to the protein degradation system, phosphorylated forkhead box class O3a, inhibitor of κBα, microRNA (miR)-1, and miR-23a, were decreased only in WT mice in response to hindlimb unloading, and 72-kDa heat shock protein expression was higher in AMPK-DN mice than in WT mice. These results imply that AMPK partially regulates unloading-induced atrophy of slow-twitch muscle possibly through modulation of the protein degradation system, especially the ubiquitin-proteasome system