Effects of various selective phosphodiesterase inhibitors on carbachol-induced contraction and cyclic nucleotide contents in the guinea pig gall bladder

The effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility and cyclic nucleotide contents in the guinea pig gall bladder were investigated. Various selective PDE inhibitors, vinpocetine (type 1), erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA, type 2), milrinone (type 3), Ro20-1724 (type 4), and zaprinast (type 5), inhibited CCh-induced contractions in a concentration-dependent manner. The rank order of potency for the gall bladder was Ro20-1724 > vinpocetine > EHNA > milrinone > zaprinast, which was different from that of the trachea, taenia coli, and aorta. In the presence of CCh (0.3 muM), vinpocetine, milrinone, and Ro20-1724 each increased cAMP content, but not cGMP. By contrast, zaprinast increased cGMP content, but not cAMP, and EHNA increased both cAMP and cGMP contents. These results suggest that vinpocetine-, milrinone-, and Ro20-1724-induced relaxation was correlated with cAMP, zaprinast-induced relaxation was correlated with cGMP, and that EHNA-induced relaxation was correlated with cAMP and cGMP in the guinea pig gall bladder. In conclusion, the effect of PDE inhibitors in the guinea pig gall bladder was different from those in smooth muscles, such as the trachea, taenia coli, and aorta.     

Simulation of Pastoral Management in Mongolia: An Integrated System Dynamics Model

High grazing density has given rise to concerns about grassland degradation in periurban areas in Mongolia. Moreover, whether livestock can increase without harming the vegetation in these areas in Mongolia and what types of policy measures should be implemented is not documented. As such, this study develops an integrated simulation model of grassland biomass, animal growth, and livestock management for a forest-steppe area in northern Mongolia and conducts a simulation on long-term changes. The simulations show that, under current conditions, the number of animals will continue to increase, while the grassland biomass will decrease. Cooperative grassland management would lead to an increase in grassland biomass and higher incomes for herders. Furthermore, herders’ population changes would have a significant impact on animal density adjustments, while the effects of conventional economic measures, such as a tax on animals, would be limited if all other conditions remain constant. Consequently, the synergistic effects of herder population changes and cooperative management can contribute toward maintaining the herders’ income while preserving the grassland ecosystem.     

Effects of high-K+, Na+-deficient solution on contractility of the smooth muscles of the bovine trachea

A high-K+, Na+-deficient (I-154 K+) solution induced contraction followed by gradual relaxation of the smooth muscles of the bovine trachea, while hyperosmotic addition of 65 mM KCl induced a large sustained contraction. Exposure of the muscle to the I-154 K+ solution induced an increase in the ratio of cellular water content and a sustained increase in oxidized flavoprotein fluorescence or reduced pyridine nucleotide fluorescence. The I-154 K+ solution also induced a sustained increase in [Ca2+]i level. Decreases in developed tension and increases in cellular water content were both prevented by the addition of sucrose or NaCl but not pyruvate. Substitution of KI for KCl in the I-154 K+ solution produced a greater inhibition of contraction, while substitution with K-propionate produced no inhibition of contraction. Moreover, decreases in developed tension and increases in cellular water content were both prevented by addition of 100 microM 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), but not 10 microM bumetanide or 1 mM acetazolamide. In conclusion, I-154 K+ solution induced-relaxation in the bovine trachea may be due to swelling of smooth muscle cells and the mechanism of swelling is probably involved in DIDS-sensitive anion movement.     

Comparative genetic mapping of homoeologous genes for the chlorina phenotype in the genus <Emphasis Type="Italic">Triticum</Emphasis>

Triticum monococcum L. (2n = 2x = 14, A^mA^m genome) is one of the most ancient of the domesticated crops in the Middle East, but it is not the ancestor of the A genome of durum wheat (T. durum Desf. 2n = 4x = 28, genomes BBAA) and bread wheat (T. aestivum L., 2n = 6x = 42, genomes BBAADD). It has been suggested that some differentiation has occurred between the A^m and A genomes. The chlorina mutants at the cn-A1 locus located on chromosome 7AL have been described in T. aestivum L. and T. durum, and a chlorina mutant has been found in T. monococcum. The aims of our study were to establish linkage maps for chlorina mutant genes on chromosome 7A of T. aestivum and T. durum and chromosome 7A^m of T. monococcum and to discuss the differentiation that has occurred between the A and A^m genomes. The chlorina mutant gene was found to be linked with Xhbg234 (8.0 cM) and Xgwm282 (4.3 cM) in F₂ plants of T. aestivum ANK-32A/T. petropavlovskyi k54716, and with Xbarc192 (19.5 cM) and Xgwm282 (12.0 cM) in F₂ plants of T. durum ANW5A-7A/T. carthlicum #521. Both the hexaploid and tetraploid wheats contained a common marker, Xgwm282. In F₂ lines of T. monococcum KT 3-21/T. sinskajae, the cn-A1 locus was bracketed by Xgwm748 (25.7 cM) and Xhbg412 (30.8 cM) on chromosome 7A^mL. The distal markers, Xhbg412, Xgwm282, and Xgwm332, were tightly linked in T. aestivum and T. durum. The common marker Xhbg412 indicated that the chlorina mutant genes are located on chromosome 7AL and that they are homoeologous mutations.     

Involvement of sex steroids,luteinizing hormone and thyroid hormones in upstream and downstream swimming behavior of land-locked sockeye salmon <Emphasis Type="Italic">Oncorhynchus nerka</Emphasis>

The involvement of testosterone (T), estradiol-17β (E₂), 11-ketotestosterone (11-KT), 17,20β-dihydroxy-4-pregnene-3-one (DHP), luteinizing hormone (LH), thyroxine (T₄), and triiodothyronine (T₃) in the regulation of downstream and upstream movement (swimming behavior) was investigated in land-locked sockeye salmon Oncorhynchus nerka, using an artificial raceway. During the downstream migratory period, T implant resulted in high plasma T levels and inhibited the occurrence of downstream swimming behavior (negative rheotaxis) in yearling (1+) immature smolts. In terms of upstream behavior, 2-year-old (2+) males exhibited high plasma T and 11-KT levels, while 2+ females had elevated T and DHP levels. In 1+ immature fish, a T implant induced upstream swimming behavior (positive rheotaxis). In experiments 1 and 3, the plasma T₄ and T₃ levels of non-migrants tended to be higher than those of migrants. In contrast, no marked changes in plasma and pituitary LH were found in both downstream and upstream migrants. These results suggest that sex steroids, such as T, play significant roles in the regulation of downstream and upstream swimming behaviors in land-locked sockeye salmon.     

Horizontal and vertical variations in survival rates of juvenile bivalves,Anadara kagoshimensis (Tokunaga, 1906), Ruditapes philippinarum (Adams & Reeve, 1850) and Atrina sp., experimentally caged in the inner area of the Sea of Ariake,Japan

International Aquatic Research - In the inner area of the Sea of Ariake, rearing experiments were conducted to examine how the survival rates of juveniles of three bivalve species (Anadara...     

Effects of fat coated rumen bypass lysine and methionine on performance of dairy cows fed a diet deficient in lysine and methionine

Two experiments were conducted to evaluate the effect of fat coated rumen bypass lysine (RPLys) and methionine (RPMet) on the lactation performance of dairy cows. In Experiment 1, three lactating cows were supplied with RPLys and fat coated DL‐Met which was highly protected (H‐RPMet) as an indigestible marker, and total fecal emission was collected for 72 h following administration. Measuring the proportional difference in fecal excretion of lysine derived from RPLys relative to methionine derived from H‐RPMet, the intestinal availability of RPLys was estimated to be 66.2%. In Experiment 2, 20 multiparous Holstein cows producing approximately 40 kg/day of milk were assigned to two treatments; fed RPLys (16 g/day as lysine) and RPMet (6.5 g/day as methionine) or none (control) from 5 to 21 weeks postpartum. The consumption of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were significantly more in the control cows throughout the experimental period. Their milk protein yield, the contents of their milk protein and milk fat were higher by 0.03 kg (P = 0.03), 0.06% (P < 0.001) and 0.11% (P = 0.07), respectively, in the treatment group compared to the control. These results suggest that the RPLys and RPMet used in this study improved the lactation performance of dairy cows.     

An improved transformation system for Lombardy poplar (Populus nigra var. italica)

We report an improved transformation system for Lombardy poplar (Populus nigra var. italica). A new binary vector, pBF2, with 11 unique restriction enzyme sites and the normal neomycin phosphotransferase II (NPTII) gene was constructed for the transformation of Lombardy poplar. Genetically transformed adventitious shoots were directly regenerated after cocultivation of stem segments with Agrobacterium tumefaciens EHA105 that harbored a binary vector with genes for the NPTII and enhanced green fluorescent protein. Successful transformation was confirmed by fluorescence microscopy, immunoblotting and Southern blotting analyses, and resistance to kanamycin and geneticin. This transformation system requires less time than our previous method for the regeneration of transgenic shoots. When explants were incubated on a smedium containing dithiothreitol, the transformation frequency increased to approximately 20%.     

PDE4 and PDE5 regulate cyclic nucleotide contents and relaxing effects on carbachol-induced contraction in the bovine abomasum

The effects of various selective phosphodiesterase (PDE) inhibitors on carbachol (CCh)-induced contraction in the bovine abomasum were investigated. Various selective PDE inhibitors, vinpocetine (type 1), erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA, type 2), milrinone (type 3), Ro20-1724 (type 4), vardenafil (type 5), BRL-50481 (type 7) and BAY73-6691 (type 9), inhibited CCh-induced contractions in a concentration-dependent manner. Among the PDE inhibitors, Ro20-1724 and vardenafil induced more relaxation than the other inhibitors based on the data for the IC₅₀ or maximum relaxation. In smooth muscle of the bovine abomasum, we showed the expression of PDE4B, 4C, 4D and 5 by RT-PCR analysis. In the presence of CCh, Ro20-1724 increased the cAMP content, but not the cGMP content. By contrast, vardenafil increased the cGMP content, but not the cAMP content. These results suggest that Ro20-1724-induced relaxation was correlated with cAMP and that vardenafil-induced relaxation was correlated with cGMP in the bovine abomasum. In conclusion, PDE4 and PDE5 are the enzymes involved in regulation of the relaxation associated with cAMP and cGMP, respectively, in the bovine abomasum.