In vivo gene transfer of PPAR gamma is insufficient to induce adipogenesis in skeletal muscle

Skeletal muscle contains several progenitor/stem cells with myogenicity as well as adipogenicity such as satellite cells. Our previous study demonstrated that forced expression of PPAR gamma is sufficient to induce transdifferentiation of predetermined myoblasts in vitro. In the present study, we examined whether introduction of PPAR gamma gene could induce adipogenesis of satellite cells in vivo. A plasmid vector containing enhanced green fluorescent protein (EGFP) or PPAR gamma gene was introduced into rat tibialis anterior muscle by electroporation. Histological analyses revealed that electroporation induces degenerative/regenerative response in skeletal muscle, including activation of satellite cells. When EGFP gene was introduced, newly formed myotubes resulted from fusion of activated satellite cells, showed EGFP expression, indicating that electroporation could transfect satellite cells with exogenously introduced gene. Gene transfer of PPAR gamma resulted in an increase of PPAR gamma-positive mononucleated cells on day 3 after electroporation but failed to induce adipogenesis thereafter. These results suggested that, in addition to an expression of PPAR gamma, niches that support adipogenesis are required for satellite cells to enter adipogenesis in vivo.     

Improved survival and growth performances with stocking density manipulation and shelter availability in bagrid catfish Mystus nemurus (Cuvier & Valenciennes 1840) larvae

Manipulation of stocking densities (10, 20, 30, 40 and 50 larvae L^?1), each with or without the presence of shelter was conducted to determine the effects on survival, cannibalism and growth performances of larval bagrid catfish Mystus nemurus (Valenciennes 1840) from 2 to 14 days after hatching. This study revealed that stocking density significantly affected survival, cannibalism, total length, feed intake, specific growth rate and final weight of bagrid catfish larvae. Significantly higher survival was observed at moderate stocking density of more than 20 but less than 50 larvae L^?1. Survival was significantly low beyond this threshold and was the lowest at 10 larvae L^?1, coincides with the highest cannibalism. Total length, feed intake, specific growth rate and final weight were significantly higher at 10 larvae L^?1. Shelter significantly improved total length and feed intake. No significant effects of stocking density and shelter were observed on the apparent feed conversion ratio and coefficient of variation. There was also no significant interaction between stocking density and shelter in all parameters. This study suggests that bagrid catfish larvae could be cultured at more than 20 but less than 50 larvae L^?1 with the availability of shelter for optimal larviculture condition.     

Induction of centrum defects in amberjack Seriola dumerili by exposure of embryos to hypoxia

ABSTRACT:   Artificially hatched Seriola species have the problem of malformation, mainly in their vertebrae, head, and mouth parts. To clarify the cause of vertebral malformation, the effects of hypoxia during embryogenesis on the induction of centrum defects was investigated in artificially hatched amberjack Seriola dumerili . Firstly, 7-somite stage embryos were exposed to waters of 0, 12.5, 25, 50, and 100% dissolved oxygen (DO) for 0.5, 1, 2, 3, 4, and 5 h to confirm the effective dose (DO concentration and duration of exposure) of hypoxia that induces somitic disturbances in newly hatched larvae. Exposure of embryos to 12.5% DO concentration for longer than 0.5 h induced somitic disturbances. Following this result, centrum defects in juveniles were investigated by an induction experiment with embryos exposed to 12.5% DO for 2 h at the gastrula, 1- or 2-somite, 10-somite, 15-somite, or heart beating stage. This experiment revealed that centrum defects were induced only during somitogenesis, and somitic disturbances were the premonitory symptom of centrum defects. These results indicate hypoxia during somitogenesis as a possible cause of centrum defects in amberjack.     

Ontogeny of digestive and immune system organs of larval and juvenile kelp grouper Epinephelus bruneus reared in the laboratory

ABSTRACT:   A histological examination was made of the ontogenetic development of the digestive and immune systems of the larval and juvenile kelp grouper Epinephelus bruneus reared in the laboratory. The liver, gall bladder, pancreas and the demarcating region between the intestines and rectum were formed within 3 days post-hatch (dph). During the preflexion phase (within 16 dph), revolution of the intestine concluded, and pharyngeal teeth and the mucous cells of the esophagus were differentiated. In the transitional period to the juvenile stage (25 dph), the blind sac of the stomach, gastric glands and pyloric caeca began to form. From the viewpoint of the differentiation phase of the adult-type digestive system, the kelp grouper is similar to Heterosomata, hitherto reported. The primordial thymus, kidney and spleen were present at 12, 1 and 6 dph, and the small lymphocytes in these lymphoid organs appeared at 21, 30 and 33 dph, respectively. The developmental sequence of the lymphoid organs and the appearance ages of the lymphoid organs and small lymphocytes in the lymphoid organs in the kelp grouper are similar to those of other marine fish previously reported, except for the Pacific bluefin tuna Thunnus orientalis .     

Arbuscular mycorrhizal dependency of different plant species and cultivars

The degree of plant growth change associated with arbuscular mycorrhizal (AM) colonization is expressed as mycorrhizal dependency (MD). In this review, previous reports on the differences in MD among plant species or cultivars were surveyed, and the factors affecting the differences are discussed. Mean values of MD were 44% for field crops (37 species), 56% for forage crops (46 species), 70% for wild grasses and forbs (140 species), 79% for trees (26 species), and 56% for all plants (250 species), indicating that the cultivated plant species showed a lower MD than the wild plant species. MD was negatively correlated with root morphological characteristics such as root length, root dry weight, root hair length, density of root hairs, the ability of roots to acquire phosphate from soil, and the phosphorus utilization efficiency of the host plant. Inoculation of arbuscular mycorrhizal fungi (AMF) for low input systems should be carried out in considering differences in MD.     

Quality Prediction of Rice Flour by Multiple Regression Model with Instrumental Texture Parameters of Single Cooked Milled Rice Grains

The purpose of this study was to develop highly accurate regression models with texture parameters of cooked milled rice grains for predicting pasting properties in terms of quality index of rice flour. Two methods were adopted as the texture measurement to acquire predictors for the models. In the calibration set, all the multiple regression models by a single‐grain method exhibited a higher R² than those by a three‐grain method. Each of the former models also showed a lower SEP and a higher RPD in the validation set. The prediction performance was best for consistency (RPD = 2.4). The single‐grain method was more advantageous for the pasting prediction. These results suggest that the models based on grain texture could predict rice flour quality.     

Plasma Membrane Lipids Are the Powerful Components for Early Stage Aluminum Tolerance in Triticale

The order of aluminum (Al) tolerance in triticale lines (ST2>ST22) after re-elongation in an Al-free 0.2 mM calcium (Ca) solution for 9 h (Ca period) following 1 h pretreatment with 20 μM Al (Al period) agreed with that after 24 h of Al treatment. Permeability of the plasma membrane (PM) of root-tip cells after the Ca period was significantly increased in Al-sensitive ST22. Al was accumulated more heavily in the root-tip portion of ST22 than in that of ST2, although similar amounts of malic and citric acid anions were released from both triticale lines. We established a new system examining lipid permeability using synthesized nylon-2,8 ultrathin and porous capsules trapped previously with 0.1% (w/v) methylene blue solution and coated thereafter with PM lipid isolated from root tips by a newly developed technique. Permeability of the PM lipid measured with time in 0.2 mM Ca with or without 50 μM Al photometrically ( A ₆₈₀) was significantly greater in Al-sensitive ST22 after 5 min of Al treatment. This is the first report to directly show the primary and early role of PM lipid in Al tolerance in triticale.     

Rhizosphere pH Profile of Rice Plant Influenced by Al Treatment

To study the mechanisms of Al tolerance in rice, we focused on the change of rhizosphere pH. The 4-d seedlings were treated with Al solution (0, 10, 50 mM) for 24 h. Then each sample was put on an agarose gel including bromocresol green, so that the color of the gel indicated pH change. During 2-h contact, the pH of rhizosphere was decreased gradually, especially for Al-treated samples, showing the specific pH profiles along the root axis. Pretreatment of sample plants with a decoupling reagent 2,4-dinitrophenol (DNP) or a plasma membrane H⁺-ATPase inhibitor Na₃VO₄ did not decrease rhizosphere pH. Therefore, it was suggested that the H⁺ secretion activity was involved with Al-tolerant mechanisms of rice.