Site of acid-base relevant ion transfer in the gills of rainbow trout (Oncorhynchus mykiss) exposed to environmental hypercapnia

In order to delineate the contribution of primary vs. secondary circulatory circuits in the gill for acid-base and ionic regulation, the flow and composition of the fluids in the central venous sinus (CVS) and the systemic circuit of rainbow trout were studied by application of a previously developed microcannulation technique during normocapnic and hypercapnic conditions. The average haematocrit (Hct) of blood from dorsal aorta (DA) and sinus venosus (SV) ranged from 20.1 to 26.7%, whereas average Hct in the fluid from the branchial vein (BV), representing drainage from the central venous sinus (CVS), was in the range of 4.2 to 7.0%. Under normocapnic conditions, the largest fraction of cardiac output, 92.9%, was directed through the systemic vascular circuit, whereas the CVS circuit was perfused with 7.1 % of cardiac output. Hypercapnia did not significantly affect the blood flow distribution between the two circuits. The pattern of acid-base regulation in dorsal aortic blood reflected the characteristic response of fish exposed to environmental hypercapnia. Upon initiation of environmental hypercapnia (2% CO₂), plasma P_{CO 2} was elevated in all three flow compartments (CVS, DA, SV), inducing an extracellular respiratory acidosis of about 0.4 pH units. pH and [HCO₃ ^-] values in the DA were consistently lower, than those for both CVS and SV sites throughout the hypercapnic period. During the 8h of exposure plasma bicarbonate concentration was elevated by about 12 mM, complemented by a fall in extracellular [Cl^-] of about 10 mM in all three compartments. The amount of HCO₃ ^- gained at the CVS site during 8h of hypercapnia (3.3 mmol · kg^-1) exceeds the amount accumulated in the extracellular space (2.1 mmol·kg^-1), suggesting the CVS as the main site of ionic acid-base regulation in trout.     

Community-based management of rural pine forests in a suburban village of Hiroshima prefecture, western Japan

Community-based management of a rural pine forest in a small suburban community, was examined and assessed. In particular, the study focused on theMatsutake project, which is an initiative seeking to help in the maintenance of a communal pine forest via the cultivation of theMatsutake mushroom by a local seniors’ group. From an ecological perspective, the maintenance work is found to be effective in the conservation and regeneration of the pine forest ecosystem, including its species diversity, especially in the herb layer. From a sociological perspective, theMatsutake project presented a valuable opportunity to strengthen connections not only within the seniors’ group, but also between senior citizens and other generations. However, subsidies for the project have tended to be gradually reduced, because it is difficult for non-involved community members to appreciate the benefits of the project. For the project to be sustainable, more widespread participation of the community is essential. A framework for wider analysis of local participatory forest management is also deemed necessary.     

Generation and alteration of norlignans in a transition zone during the drying of a Cryptomeria japonica log

Sugi (Cryptomeria japonica D. Don) produces secondary metabolite norlignans in xylem. Several norlignans are involved in the coloration of heartwood and defense of sapwood against microbial invasion. Their biosynthetic process should be well understood so that their properties can be exploited to improve the quality and utility of C. japonica wood. Unfortunately, information on the norlignan biosynthesis is limited because norlignans are mainly synthesized in a particular season in the transition zone (TZ) along with the heartwood formation, and is difficult to study. Although the generation of two norlignans of C. japonica, agatharesinol and (E)-hinokiresinol, has been reported, systems for producing other norlignans are not yet known. To establish a novel norlignan generating system, we examined the changes occurring in norlignans in a TZ during the process of drying a C. japonica log. On the day of felling, the TZ contained agatharesinol and (E)-hinokiresinol, which increased until they reached a maximum on day 40 after felling. Sequirin-C appeared on day 40 and increased to day 70. The generation of sequirin-C in the TZ can be used to investigate the biosynthetic process of heartwood norlignans. This study describes for the first time the changes that occur in the composition of norlignan during the drying of the TZ.     

Discrete sandwich compounds of monolayer palladium sheets

Despite the abundance of "sandwich" complexes, in which two cyclic aromatic hydrocarbon ligands flank a metal center, this motif has not been extended to sheets of multiple metal atoms. We prepared and isolated two such compounds. In the first, three palladium centers form a planar triangular array, capped by chlorides, between two cycloheptatrienyl ligands. In the second, a pentapalladium sheet adopts an edge-sharing triangle-trapezoid skeleton between two naphthacene rings. The compounds were characterized by x-ray crystallography and nuclear magnetic resonance spectroscopy. The nature of bonding in the clusters was analyzed by quantum calculations.     

The palliative efficacy of modified Mohs paste for controlling canine and feline malignant skin wounds

In veterinary medicine, the management of malignant skin wounds is highly challenging. We conducted a study on seven case animals (four dogs and three cats) which presented with malignant skin wounds. All seven animals had signs and symptoms which were controlled following treatment with a modified Mohs paste. Upon obtaining informed consent from their owners, the animals requiring management of malignant wounds were enrolled in this study. The modified Mohs paste was prepared by mixing zinc chloride, zinc oxide starch powder, glycerin, and distilled water. The modified Mohs paste was topically applied to and left to remain on the malignant wounds for one hour, under controlled conditions. Once the paste was removed, the wounds were irrigated with a solution of sterile saline. At the first examination, the wounds of each animal were observed for signs of exudate, malodor, and bleeding. In every case, visible improvement was observed immediately after the modified Mohs paste treatment. Specifically, the size of the malignant wounds, and the number of times the dressing gauze required changing, significantly decreased (p < 0.05 and p < 0.01, respectively). The open malignant skin wounds caused by mammary gland tumors disappeared in two cases. The Mohs paste has been shown to be a viable option for the palliative treatment in canine and feline malignant skin wound management.     

Sarcoplasmic Reticulum Ca2+-ATPase Activity and Glycogen Content in Various Fiber Types after Intensive Exercise in Thoroughbred Horses

To find a new parameter indicating muscle fitness in Thoroughbred horses, we examined time-dependent recovery of glycogen content and sarcoplasmic reticulum (SR) Ca²⁺-ATPase activity of skeletal muscle after intensive treadmill running. Two repeated 50-sec running sessions (13 m/sec) were performed on a flat treadmill (approximately 90%VO₂max). Muscle samples of the middle gluteal muscle were taken before exercise (pre) and 1 min, 20 min, 60 min, and 24 hr after exercise. Muscle fiber type composition was determined in the pre muscle samples by immunohistochemical staining with monoclonal antibody to myosin heavy chain. SR Ca²⁺-ATPase activity of the muscle and glycogen content of each muscle fiber type were determined with biochemical analysis and quantitative histochemical staining, respectively. As compared to the pre value, the glycogen content of each muscle fiber type was reduced by 15–27% at 1 min, 20 min, and 60 min after the exercise and recovered to the pre value at 24 hr after exercise test. These results indicate that 24 hr is enough time to recover glycogen content after short-term intensive exercise. The mean value of the SR Ca²⁺-ATPase activity showed a slight decrease (not significant) immediately after exercise, and complete recovery at 60 min after exercise. There were no significant relationship between the changes in glycogen content of each muscle fiber type and SR Ca²⁺-ATPase. Although further studies are needed, SR Ca²⁺-ATPase is not a useful parameter to detect muscle fitness, at least in Thoroughbred horses.     

The smell and odorous components of dried shiitake mushroom, Lentinula edodes V: changes in lenthionine and lentinic acid contents during the drying process

This study on dried shiitake mushroom [Lentinula edodes (Berk.) Pegler] focuses on the behavior of the aromatic lenthionine compound and its precursor, lentinic acid, during the drying process. Only a small amount of lenthionine was present after the drying process, regardless of the drying temperature or time; however, the amount increased during the rehydration process using pH 8.0 buffer. The lenthionine content after incubation in the buffer was correlated with the lentinic acid content in the dried shiitake mushroom. The lentinic acid content increased signifi cantly during the drying process at 40°C up to 4 h. The results show that the characteristic smell of dried shiitake mushroom was weak after drying, and that rehydration in a mild alkaline solution was necessary to increase the smell. The lentinic acid content of dried shiitake could serve as an indicator of the smell produced by rehydration and would be useful in screening to select odor-rich strains. Moderate heating likely caused the increase in lentinic acid content, which might be related to a reaction to heat.     

Effect of support on the growth of a woody vine,Wisteria floribunda DC. (Leguminosae)

Seedling ofWisteria floribunda, which belongs to the twiner type of climbing plants, were planted in nursery and the effect of support on the growth of the seedlings was tested. The seedlings were grown with 240 cm-height and 120 cm-height supports (the culms of a dwarf bamboo), and without support. Positive effect of the supports and its length were observed for stem length ofW. floribunda at the end of the growing season. The positive effect of support was also observed for total dry weight. Total dry weight with 240 cm-height support reached more than the double of the seedlings without support. These effects of the support were attributed to die-back behavior of the twining stem, which detached from the support or did not encounter the support. Diameter of the stems without support showed a rapid decrease toward the stem tip, while that with support were relatively constant when they were twining around the support. The existence of the support also affected the dry matter allocation in this species; supported seedlings allocated larger proportion of biomass to current-year stems than unsupported seedlings, although the allocation to the roots was smaller in the supported treatments. Support availability may be critical for the establishment and further growth of the seedlings ofW. floribunda which regenerate at the forest edge and canopy gaps. A part of this report was presented at the 107th Annual Meeting of the Japanese Forestry Society, at Tsukuba, April, 1996.