Assessment of the water quality of two rivers in Hanoi City and its suitability for irrigation water

The To Lich and Kim Nguu Rivers in Hanoi City are the main sources of irrigation water for suburban agricultural land and fish farm. Wastewater from the industrial plants located along these rivers has been discharged, and has degraded the water quality of the rivers. This study describes the chemical properties of water from the rivers, focusing on heavy metal pollution and the suitability of water quality for irrigation water. Water from the rivers was heavily polluted with organic matter and heavy metals such as Pb, Cu, Zn, Cr, Cd and Ni. Dissolved oxygen, chemical oxygen deman, and total suspended solids, and the concentrations of all heavy metals exceeded the Vietnamese standard for surface water quality in all investigated sites. The concentrations of some heavy metals such as Cu, Cd, Cr and Ni were above the internationally recommended WHO maximum level for irrigation water. A wide variation in the heavy metal concentration of water due to metal types is the result of wastewater discharged from different industrial sources.     

Ultrastructural studies of spermatia of grey mould (<Emphasis Type="Italic">Botryotinia fuckeliana</Emphasis>)

To investigate maturation of spermatia of Botryotinia fuckeliana, we examined micro-structural changes in spermatia in liquid culture. Three to four spherical lipid bodies were seen in the center of the cell at the start of culturing. After 3–7 days, maturing spermatia had developed large mitochondria along with extensively developed granular endoplasmic reticulum. In contrast, the lipid bodies decreased not only in number but also in size over time. The results obtained here suggest that the maturation of spermatia involves active cell metabolism using the energy supply from lipid bodies.     

Bending creep behavior of hot-pressed wood under cyclic moisture change conditions

This study examined the bending creep behavior of hot-pressed wood during cyclic moisture changes. Sugi (Cryptomerica japonica D. Don) specimens were pressed in the radial direction under six combinations of nominal compressive strain (33% and 50%) and press temperatures (140°C, 170°C, 200°C). Creep tests were conducted at 20°C with three cyclic relative humidity changes between 65% and 95% under 25% of short-breaking stress. The effect of moisture content (MC) change on elastic compliance and mechanosorptive (MS) compliance was investigated. The relation between MS compliance and thickness swelling was studied. The results indicated that total compliance increased over the history of cyclic moisture changes; and its behavior was closely related to the changes in MC and thickness swelling. The total compliance increased during adsorption and decreased during desorption. Elastic compliance increased linearly with MC and was dependent on press temperature and compression. With increasing MC change, MS compliance increased during adsorption and decreased during desorption. The first adsorption led to greater MS compliance than did the subsequent adsorption with the same amount of MC change. In general, the elastic parameterK _E and the MS parameterK _Mincreased with compression and decreased as the press temperature increased. The MS parameterK _M was apparently greater than the elastic parameterK _E. The MS parameterK _M increased with swelling coefficient K_SW of the hot-pressed specimen during adsorption and decreased with an increasing shrinkage coefficientK _SH during desorption.     

An enzyme-linked immunosorbent assay using canine coronavirus-infected CRFK cells as antigen for detection of anti-coronavirus antibody in cat

From the reasons that canine coronavirus (CCV) grows more efficiently than feline coronavirus in a cell culture and they are mutually related in their antigenicities, an enzyme-linked immunosorbent assay (ELISA) using CCV-infected feline kidney (CRFK) cells as substrate antigens was developed for detection of anti-coronavirus antibodies in cats. It was indispensable for generating coronavirus-specific ELISA antibody activities that the sample was applied to the mock-infected, normal CRFK cells in parallel with the CCV-infected cells and then the optical density values given by the mock-infected cell antigen were subtracted from those given by the virus-infected cell antigen. On the basis of ELISA antibody titers obtained in sera from the cats experimentally infected with CCV and from the spontaneous feline infectious peritonitis (FIP) cases, the ELISA described in the present study was found to be applicable as a simple and easy serologic test which was able to detect anti-coronavirus antibodies as efficiently as the indirect immunofluorescence assay with homologous FIP virus.     

Caulogenic callus induction and adventitious bud formation from embryos of long-term stored seeds ofPicea jezoensis

Caulogenic calli with a high differentiation potency were induced from mature embryos ofPicea jezoensis seeds stored over a long time, for 29 years, resulting in the active formation of adventitious buds. Embryos began to induce calli within 3 weeks of cultivating on LP medium containing 3 μM BAP and 1 μM 2,4-D. Then, the calli proliferated and transformed into caulogenic calli with bud primordia in 8 weeks. The caulogenic calli increased actively with the addition of 500 mg/l ofl-glutamine in the medium. Furthermore, caulogenic calli, induced on LP medium containingl-glutamine, resulted in the formation of adventitious buds, which elongated after transferring the calli into LP medium with 0.1 μM BAP, but withoutl-glutamine. It appears that the number of adventitious buds and the process of shoot elongation are influenced by the kind of nitrogen contained in the medium for callus induction. A part of this study was presented at the 107th Annual Meeting of the Japanese Forestry Society (1996).     

Contributions of salmon-derived nitrogen to riparian vegetation in the northwest Pacific region

We examined the relationship between the annual escapement of salmon and the δ ¹⁵N of willow (Salix spp.) leaves to evaluate the contribution of marine-derived nutrients (MDN) to riparian vegetation around the Pacific Northwest and Northeast regions. Foliar δ ¹⁵N values ranged from −3.42‰ to 4.65‰. The value increased with increasing density of carcasses up to 500 fish/km and 1500 fish/km. δ ¹⁵N values were variable at carcass densities below 500 fish/km. Possible factors affecting the fluctuation of δ ¹⁵N at reference sites are: (1) denitrification; (2) the presence of N₂-fixing trees, such as alder; and (3) agricultural runoff. δ ¹⁵N values at the sites with carcass densities over 500 fish/km were consistently high, while a value of δ ¹⁵N below zero was observed at only one site (Rusha River; δ ¹⁵N = −1.87‰). At this site, most adult pink salmon returned to limited locations near the estuary because steeper channel gradients acted as a migration barrier, resulting in the negative δ ¹⁵N value. Nevertheless, we concluded that our results showed evidence of the feedback of MDN to terrestrial vegetation, although the use of the δ ¹⁵N value as a terrestrial end member at spawning sites is limited. If the relationship between the enrichment index, which is expressed as the values using a mixing model, and salmon abundance was estimated, the availability of MDN in riparian ecosystems could possibly be evaluated and will lead to the establishment of escapement goals. An erratum to this article is available at .     

New method to evaluate water-soluble antioxidant activity based on protein structural change

A simple method to evaluate antioxidant activities of water-soluble ingredients of foods has been developed. Protective effects of antioxidants against hypochlorite radical or hydroxyl radical have been studied by comparing changes in absorbance of myoglobin (a standard reference) at 409 nm. Protective ratio, defined by absorbance changes of myoglobin with or without the antioxidant, was a good indicator to quantitatively evaluate the antioxidant activity against the hypochlorite radical or the hydroxyl radical, respectively. Radar charts indicating the antioxidant activities against DPPH (1,1-diphenyl-2-picrylhydrazyl), hypochlorite radical, and hydroxyl radical clearly differentiated the characteristics of five antioxidants including carnosine, glutathione, and vitamin C. By comparison of the radar charts, antioxidant activity of bonito meat hydrolysate was found to have similar characteristics to that of carnosine. The simple method proposed in this study would be useful for evaluating and characterizing the activities of water-soluble antioxidants contained in various food materials.     

Short term change of urinary N-acetyl-beta-D-glucosaminidase in reduced kidney mass with renal artery ligation

The aim of the present study was to evaluate short term urinary NAG levels in a model of reduced kidney mass. The half and quarter kidney mass were made from ligation of the renal artery. Both groups decreased in the level of excreted NAG on day 1 and 2 after operation. On day 5 after operation, both groups achieved urinary enzyme levels comparable to that of the sham-operated group. The remaining compensated nephrons held normal range of excreted urinary NAG levels, although reduced number of nephrons resulted in a decline in urinary NAG levels.     

Segmentation of the Pathophysiological Stages of Diabetic Changes in the db/db Mouse

The db/db mouse is one of the diabetes mellitus animal models and if the pathophysiological stages of diabetic changes in the mouse model could simulate the stages in human diabetes, the db/db mouse could be used to better evaluate drug candidates. Blood insulin, HbA1c levels and morphological features of pancreatic islets in db/db mice were evaluated to determine the pathophysiological stage. At 6 weeks of age, db/db mice showed the highest level of plasma insulin and lowest level of HbA1c, and histopathological examination revealed enlarged islets with a circular shape and hypertrophic islet cells. By 9 and 12 weeks of age, the plasma insulin levels had decreased to mid levels and HbA1c had increased to mid to high levels; histopathological examination at this time revealed two types of islets coexisting, enlarged circular islets and small irregular-shaped islets. By 15 and 22 weeks of age, plasma insulin had decreased further to low levels and HbA1c was at its highest level; the histopathological examination at this time revealed an increase in irregular-shaped and small islets. Based on blood insulin levels, HbA1c levels and histopathology findings in the db/db mice in this study, the clinical staging of diabetic changes were recognized. The pathophysiological stages of diabetes mellitus in this animal model were similar to the stages in humans.     

Effects of cycloheximide treatment on in-vitro development of porcine parthenotes and somatic cell nuclear transfer embryos

This study aimed to verify the beneficial effect of cycloheximide (CHX) treatment on the development of porcine somatic cell nuclear transfer (NT) embryos, which were constructed with enucleated oocytes and cumulus cells by using a single direct current (DC) pulse. In the first experiment, a single DC pulse applied to the induction of fusion and activation of NT embryos gave a high fusion rate. However, cleavage and subsequent development of fused couplets (NT embryos) to the blastocyst stage were poor. Experiment 2 was conducted to determine whether CHX treatment could enhance metaphase II (M II) oocyte activation and improve the subsequent parthenogenetic development. After giving the DC pulse and incubation with or without CHX, M II oocytes incubated with CHX showed higher cleavage and development to blastocysts compared with those incubated without CHX (P < 0. 05). Experiment 3 was carried out to verify the beneficial effect of CHX on the development of NT embryos. The NT embryos treated with the DC pulse and CHX treatment showed higher cleavage and subsequent development compared with those treated with the DC pulse alone (P < 0.05) . The present study demonstrates that CHX treatment enhances the electrical stimulus-induced activation of oocytes and NT embryos, and improves the subsequent development of parthenotes and NT embryos. The results indicate that protein synthesis inhibition treatment required for the induction of oocyte activation promotes the development of NT embryos.