Application of the coastal ecosystem complex concept toward integrated management for sustainable coastal fisheries under oligotrophication

Harmonizing coastal fisheries with water-quality improvement has become an essential factor for the sustainable use of coastal ecosystem services. Here, we present the scope of our study based on an interdisciplinary approach including ecological actions, socio-economic actions and socio-psychological actions. We chose to focus on the interaction between oyster aquaculture and seagrass vegetation as a typical ecological action using the coastal ecosystem complex (CEC) concept. Coastal organisms have adapted their traits to the environment over a long period of time, so that restoration of the CEC represents reconstruction of the original process of coastal production. Subtidal seagrass vegetation with intertidal oyster reefs is the original CEC in Japan, which would be expected to enhance coastal production by improving the production efficiency without adding nutrients. A simple field experiment examining carbon and nitrogen contents and stable isotope ratios revealed that oyster spats cultivated on a tidal flat adjacent to seagrass beds had higher nitrogen contents and higher δ¹³C ratios than spats cultivated in an offshore area using only pelagic production. This result suggests that utilization of the CEC, which enables oysters to use both pelagic and benthic production, has potential to sustain a food provisioning service for humans, even in oligotrophic conditions.     

An angiotensin converting enzyme inhibitor,benazepril can be transformed to an active metabolite,benazeprilat, by the liver of dogs with ascitic pulmonary heartworm disease

To examine whether an angiotensin converting enzyme (ACE) inhibitor, benazepril, can be transformed to the active metabolite, benazeprilat, by severely injured liver of dogs with ascitic heartworm disease, benazepril hydrochloride was administered orally to dogs once daily for 7 consecutive days at a dose rate of 0.29 mg/kg to 0.63 mg/kg of body weight, and plasma benazepril and benazeprilat concentrations were determined on the 1st and 7th administration days. In 7 dogs with ascitic pulmonary heartworm disease, plasma benazeprilat concentrations tended to be higher than in 7 control dogs both on the 1st and 7th administration days. The peak concentration and area under the concentration-time curve tended to be greater in dogs of the ascites group than in control dogs, but the statistics could not detect significant differences in the time to peak concentration and t(1/2) between the control and ascites groups. Plasma ACE activities decreased after administration of benazepril. In dogs with ascitic heartworm disease, benazepril was readily transformed to benazeprilat by the liver, and was effective for suppression of plasma ACE activity.     

Phagocytosis of bovine blood and milk polymorphonuclear leukocytes after ozone gas administration in vitro

To determine the effects of ozone on the phagocytosis of bovine polymorphonuclear leukocytes (PMNs), ozone gas was administered in vitro on the blood and milk of healthy lactating cows, cows with acute mastitis, and cows with milk fever. In the blood of healthy dairy cattle, although there was no significant effect of ozone gas on the viability of the leukocytes, phagocytosis of PMNs significantly decreased. In contrast, ozone gas administration in vitro significantly increased phagocytosis of PMNs from the blood of cows with acute mastitis and milk fever, and from mastitic milk. These findings showed that ozone administration in vitro has positive and negative effects on bovine PMN phagocytosis, depending on the health status of the animal.     

Uptake and translocation of bleaching herbicidal compounds in radish seedlings

The relationship between the hydrophobicity of certain herbicidal compounds and the bleaching pattern caused on radish cotyledons was investigated. Seed treatment with diphenylpyridones, as well as with established herbicides, produced three types of bleaching pattern according to their hydrophobicity. The less hydrophobic compounds caused complete bleaching of both cotyledons, but the compounds with more hydrophobicity caused only partial bleaching. The critical points for whole or partial bleaching were in the range of log K_ow 4–5 (K_ow: octanol/water partition coefficient), and these values were changed slightly with their chemical classes. Uptake of compounds into the seed coat took place rapidly; these compounds were then translocated slowly from the seed coat to the embryo, namely, radicle, abaxial surface of one cotyledon and marginal areas of both cotyledons. Application of these compounds to roots resulted in initial translocation to marginal areas of both cotyledons, with subsequent translocation to the middle area. It is believed that compounds taken up into the radicle were translocated to both cotyledons in a manner similar to that following application to roots. These effects following uptake by seeds can be used as a translaminal and lateral transport assay for bleaching herbicidal compounds in cotyledons.     

Determination of lignin,holocellulose, and organic solvent extractives in fresh leaf,litterfall, and organic material on forest floor using near-infrared reflectance spectroscopy

We report the results of a study regarding the near-infrared reflectance spectra of various leaf stages from fresh to senescing, and to decomposing leaf. A broad absorbance feature increased in the region of 1100–1400nm with the advance of the leaf senescence and leaf decomposition. A decrease was seen in the region over 1440nm during the senescence and decomposition process. These differences of spectra showed the changes in constituents of leaf in terms of the degree of the senescence and decomposition. A comparison of multiple linear regression between the near-infrared reflectance spectra and proximate chemical analyses showed that near-infrared reflectance spectroscopy achieved a certain level of useful accuracy. We consider that near-infrared reflectance spectroscopy has the potential to predict the contents of carbon fractions in plant materials, and that this method can replace previous methods due to faster determination of carbon fractions, and its ability to significantly increase the number of samples that can be collected and measured.     

Soil respiration and soil CO<Subscript>2</Subscript> concentration in a tropical forest,Thailand

Soil respiration and soil carbon dioxide (CO₂) concentration were investigated in a tropical monsoon forest in northern Thailand, from 1998 to 2000. Soil respiration was relatively high during the rainy season and low during the dry season, although interannual fluctuations were large. Soil moisture was widely different between the dry and wet seasons, while soil temperature changed little throughout the year. As a result, the rate of soil respiration is determined predominantly by soil moisture, not by soil temperature. The roughly estimated annual soil respiration rate was 2560gCm^–2year^–1. The soil CO₂ concentration also increased in the rainy season and decreased in the dry season, and showed clearer seasonality than soil respiration did.     

覆盖作物对土壤物理特性及旋耕作业的影响分析

覆盖作物可改善土壤持水能力,但是对土壤硬度的影响与土壤含水率有关。对覆盖作物进行耕前割倒作业可解决旋耕作业时在旋耕刀辊上产生的缠绕问题。大量作物残茬置于土壤表层会影响后续作物的播种质量和出芽率,所以对于干物质量大的覆盖作物不宜直接采用旋耕作业。     

Variation in Amylase Activities in Radish (<Emphasis Type="Italic">Raphanus sativus</Emphasis>) Cultivars

The radish (Raphanus sativus) is a root vegetable of the Brassicaceae family which shows amylolytic activity in the taproot. However, there is little information about differences in these amylolytic activities among radish cultivars. We analyzed the amylase activities and starch contents of 7 kinds of radish cultivars. The Koshin cultivar showed the highest amylase activity, with a level approximately 6 times higher than that of the Sobutori cultivar, which had the lowest. Cultivars with higher amylase activities showed higher starch contents. These results suggest that there are intraspecies variations in amylolytic activities in radishes, and positive correlations between amylase activity and starch content.     

Effects of heavy metal accumulation in apple orchard soils on microbial biomass and microbial activities

Abstract

The effects of heavy metals (Cu, Pb, and As) accumulated in apple orchard surface soils on the microbial biomass, dehydrogenase activity, and soil respiration were investigated. The largest concentrations of total Cu, Pb, and As found in the soils used were 1,010, 926, and 166 mg kg^?1 soil, respectively. The amounts of microbial biomass C and N, expressed on a soil organic C and soil total N basis, respectively, were each negatively correlated with the amounts of total, 0.1 M HCI-extractable, and 0.1 M CaCl₂-extractable Cu as logarithmic functions, the correlation coefficient being lowest for the 0.1 M CaCl₂extractable Cu. Nevertheless, they were not correlated with the soil pH which was controlling the solubility of Cu in 0.1 M CaCl₂. The dehydrogenase activity expressed per unit of soil organic C was also negatively correlated with the amounts of total, 0.1 M HCI-extractable Cu, and 0.1 M CaCl₂-extractable Cu as logarithmic functions. However, the correlation coefficient was highest for the 0.1 M CaCl₂-extractable Cu. Although the soil respiration per unit of soil total organic C did not show any significant correlations with the total concentrations of heavy metals, it showed negative significant correlations with the amount of 0.1 M HCI-extractable Cu, and to a greater extent, with the amount of 0.1 M CaCl₂-extractable Cu. Both the dehydrogenase activity and respiration per unit of soil total organic C increased significantly with increasing soil pH. These results suggested that in apple orchard soils with heavy metal accumulation the microbial biomass was adversely affected by the slightly soluble Cu, whereas the microbial activities by the readily soluble Cu whose amount depended on the soil pH. The respiration per unit of microbial biomass C showed a positive significant correlation with the logarithmic concentration of total Cu. Furthermore, the contribution of fungi to substrate-induced respiration increased with increasing total Cu content in the soils.     

Sequential synaptic excitation and inhibition shape readiness discharge for voluntary behavior

How do animals initiate voluntary behavior? A key phenomenon in neuroscience is the readiness or preparatory neural activity in specific regions of the animal brain. The neurons and synaptic mechanisms mediating this activity are unknown. We found that the readiness discharge is shaped by sequential synaptic excitation and inhibition in the brain of crayfish (Procambarus clarkii). The readiness discharge neurons extended axon collaterals that appeared to activate recurring local interneurons. Therefore, we propose that the readiness discharge is formed by sequential synaptic events within the brain without feedback signals from downstream ganglia. The circuit involved is suited for signal processing for self-generated voluntary initiation of behavior.