Showing papers in "Jarq-japan Agricultural Research Quarterly in 2007"

Evaluation of CFD Accuracy for the Ventilation Study of a Naturally Ventilated Broiler House

Abstract: Using the CFD model, a new ventilation system design will be found later taking into consideration the ventilation efficiency such as uniformity, stability, and suitability of environmental factors in a naturally ventilated broiler house. Because conducting a field experiment for the ventilation study presented so many difficulties, a reliable 3-dimentional computational fluid dynamics (CFD) model had to be developed to investigate the natural ventilation. Before investigating its accuracy, a wind tunnel and particle image velocimetry (PIV) test was initially conducted to find their best experimental conditions and improve the PIV accuracy 13 15 A 1/20 scale model of a naturally ventilated broiler house was used to get qualitative and quantitative airflow distribution in the broiler house using the PIV and CFD. To improve the CFD accuracy, the PIV and CFD computed airflows in the broiler house were compared, particularly on the distribution, local air velocity, and turbulent intensity in the house. The quality of the mesh density and the design of the boundary condition, especially the wind velocity and turbulence profiles, were found to be very important for getting accurate results. Assuming the PIV results were accurate, the most accurate CFD results were obtained when using a RNG k-e turbulence numerical model. The average error of the CFD computed air velocity when using the RNG k-e models was -6.2%.

Biomethanol Production and CO2 Emission Reduction from Forage Grasses, Trees, and Crop Residues

Abstract: With a wide array of potentially renewable energy resources, the concept and proposed benefits evolving from the use of biofuels are inspiring. Recently, a new approach for gasification of biomass by partial oxidation and subsequent biomethanol production has been developed and is being evaluated at the "Norin Green No. 1 (renamed as Norin Biomass No. 1)" test plant in Nagasaki, Japan. To determine a useful protocol for producing biomethanol, various kinds of biomass resources, such as sawdust and bark of Japanese cedar, chipped Japanese larch, bamboo, salix, cut waste wood from demolition sites, sorghum, and bran, straw, and husks of rice were evaluated for their biofuel-use characteristics. From this analysis, lignocellulosic resources (wood materials) and rice bran were estimated to produce a high methanol yield (55% by weight), whereas rice straw and husks were estimated to produce lower methanol yield of 36% and 39%, respectively. On the basis of the data obtained from the test plant, the net heat yield by the methanol production of a full-scale commercial plant was estimated to be ca. 40%. Each of these products is a clean material, readily obtained and highly useful for biomethanol production. Developing nations interested in constructing a national energy policy should focus upon the establishment of a biofuel-based economy. Recycling of agricultural and forest industry by-products has been previously shown to reduce the demand for fossil fuels and provides a more ecologically friendly energy resource. Our research suggests that additional sources of biomethanol production could be developed through the utilization of cellulosic and lignocellulosic raw materials.

Development of New Sets of International Standard Differential Varieties for Blast Resistance in Rice (Oryza sativa L.)

Abstract: The IRRI-Japan Collaborative Research Project has been developing new sets of differential varieties for resistance to blast disease (Pyricularia grisea Sacc.) in rice (Oryza saliva L.). The first international standard differential variety set composed of monogenic lines for 24 kinds of resistance genes (Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pit. Pita. Pita-2, Piz, Piz-5 (= Pi2), Piz-t, Pil, Pi3 , Pi5(t), Pi7, Pi9, Pi11(t), Pi12(t), Pi19(t), and Pi20) was released and has been widely used in various countries. Furthermore, the project has been developing near-isogenic lines (NILs) for blast resistance with three kinds of genetic backgrounds, a Japonica-type variety Lijiangxintuanheigu (LTH), an Indica-type variety C039, and a newly developed 'universal susceptible' line US-2 which was derived from a cross between Indica and Japonica-type susceptible varieties. A total of 23 lines for 14 kinds of resistance genes, Pia, Pib, Pik, Pik-h, Pik-s, Pita, Pita-2, Piz-5 (= Pi2), Piz-t, Pil, Pi3, Pi5(t), Pi7, and Pi9, have been developed by the recurrent backcross method using the monogenic lines with the LTH genetic background. Twenty lines for 14 kinds of resistance genes, Pib, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pita, Pita-2, Piz-5 (= Pi2), Piz-t, Pil, Pi5(t), and Pi 7 have been developed with the CO39 genetic background. Moreover, a universal susceptible rice line, US-2, which has not been known to have any blast resistance genes in the genetic background, and can be cultivated easily under both tropical and temperate conditions, is also being used for the development of NILs as the next generation of differential varieties. These lines are offered as gene sources for breeding of blast resistance and as sets of international standard differential varieties used for the study of blast disease.

Lactococcus sp. as Potential Probiotic Lactic Acid Bacteria

Abstract: The most widely used probiotic bacteria are lactobacilli and bifidobacteria, which have been isolated from the human gastrointestinal tract. The development of new probiotic strains, which are more feasible and beneficial organisms, is awaited in the dairy industry. Lactococci would be promising species because of their extensive usage in manufacturing dairy products such as cheese and fermented milk. However, there have been few studies on the probiotic activity of lactococci since they are traditionally not considered to be natural inhabitants of the human gastrointestinal tract. Recently, several works showed the possibility of the presence of lactococci in the flora of the human or animal gastrointestinal tract. In this review, we would like to propose Lactococcus sp. as new probiotic bacteria.

Response of Tomato Root Systems to Environmental Stress under Soilless Culture

Abstract: We investigated the effects of root-zone environment, humidity around the roots and nutrient solution on the activity and morphology of tomato roots grown in wet-sheet culture (exposed to air) or deep flow technique (submerged in solution) Differences in root external and internal structure between treatment groups could be interpreted as adaptive responses to the root environment The exposed roots could adapt more readily to extremes of temperature than those in the solution Those adaptations occurred through short-term physiological responses and long-term additive morphological responses We also evaluated the facilitating effects of the flow of nutrient solution on root respiration and nutrient uptake rate Where the root system was split between humid air and nutrient solution, roots in the solution absorbed and supplied nitrogen more efficiently per dry weight than did roots in air Split root systems between humid air and nutrient solution showed stable growth of tomato plants Our observations of root plasticity will help the establishment of growing systems that support high yield and stable production

Cucurbitacin C—Bitter Principle in Cucumber Plants

Abstract: Cucumber plants contain a bitter substance, cucurbitacin C. The compound was isolated from cucumber leaves using preparatory HPLC (high performance liquid chromatography) to investigate the relationship between its content and bitterness of the plant parts. An analytical method for cucurbitacin C using HPLC was also established. A Japanese popular cultivar, 'Sharp 1' contained the compound in the leaves but not in the fruits, while a unique cultivar with white skin 'Shinsyo Hakuhi' contained it both in leaves and fruits. The stem end of 'Shinsyo Hakuhi' fruit contained higher amounts of it than other fruit parts. Cucurbitacin C is a strongly bitter component and its threshold level was less than 0.1 mg/L. The bitter sensation felt when biting the plant parts could be interpreted as corresponding to the content of cucurbitacin C.

Microbial Control of Fresh Produce using Electrolyzed Water

Abstract: The demand for fresh salad vegetables, such as iceberg lettuce, has increased worldwide in recent years. Numerous sanitizers have been examined for their effectiveness in killing or removing pathogenic bacteria on fresh produce. However, most of the sanitizers are made from the dilution of condensed solutions which involves some risk in handling and is troublesome. A sanitizer that is not produced from the dilution of a hazardous condensed solution is required for practical use. Electrolyzed water and ozonated water were investigated for bactericidal effects on fresh-cut produce as a convenient and safe alternative sanitizer. Although the efficacy of acidic electrolyzed water (AcEW) as a sanitizing agent was dependent on the kind of produce treated, AcEW could be sufficiently effective to offer an alternative solution to conventional sanitizers, such as sodium hypochlorite solution (150 ppm). A novel produce-washing procedure using a combination of alkaline electrolyzed water (AIEW), AcEW and mild heat demonstrated significant bactericidal effect compared with the treatment with ambient temperature. Besides the bactericidal effect, the progress of browning on lettuce was suppressed by using mild heat treatment. Furthermore, as a novel usage of AcEW, we examined the use of AcEW-ice for preserving vegetables. AcEW-ice inactivated the spoilage and pathogenic bacteria on lettuce and reduced the temperature of lettuce during storage.

Diversity and Community Structure of Macrobenthic Fauna in Shrimp Aquaculture Ponds of the Gulf of Thailand

Abstract: To compare the diversity and community structure of macrobenthic fauna inhabiting shrimp aquaculture ponds, quantitative samplings using a multilayer cylinder were carried out in culture experimental ponds at Samut Songkhram, along the innermost part of the Gulf of Thailand. A total of 25 species/taxa of macrobenthic organisms were identified from the six aquaculture ponds; four ponds used for active shrimp (Penaeus monodon Fabricius) culture and two ponds planted with mangrove stands (Rhizophora mucronata Lamarck). The dominant species belonged to three taxonomic categories; that is, (1) sedentary, tube-dwelling spionid, Polydora sp., free-living nereid, Perinereis sp., and some other polychaetes (Annelida), (2) gastropods such as Cerithidea cingulata, Cerithium coralium, Thiara riqueti ,a nd Stenothyra spp. which live on the surface or in the shallow layer of the substratum (Mollusca), and (3) barnacles, Balanus sp., and some small arthropods such as ostracods, copepods, harpacticoids, amphipods, and dipterans (Arthropoda). Maximum density and biomass exceeded 10,000 individuals/m 2 and 600 g/m 2 , respectively, and gastropods were the most dominant and representative taxa in most of the ponds. Species composition was clearly distinguished between the shrimp culture ponds and the mangrove planted ponds. Population density, species richness and species diversity indices of macrobenthic organisms in the bottom of the mangrove planted ponds were significantly higher than those of the shrimp culture ponds, suggesting that mangrove was important for maintaining and increasing the biodiversity. There was a tendency that epibenthic mollusks and arthropods decreased evidently as the depth increased from the surface to the deeper layers, while annelids were found not only in the surface layer but also in the moderately deeper layer. A possibility that Penaeus monodon fed on some macrobenthic organisms under the cultured conditions was discussed.

Dependence of Solar Radiation Transport in Rice Canopies on Developmental Stage

Abstract: Solar radiation in a rice canopy plays an important role in the energy balance on both the plant leaves and soil/water surface. A simple model was derived from the two-stream model to estimate two important factors characterizing radiation in a plant canopy, namely, transmissivity of the canopy (τc) and the albedo of the canopy (ref), from the absorption coefficient of leaves (a) and leaf inclination factor (F). To clarify the seasonal variation in a and F with growth, season-long observations were conducted in paddy fields during three different cropping seasons. Values of a were almost constant throughout the growing period; however, values of F tended to increase with growth. Values ofF were larger than 0.5 (the theoretical value for random leaf distribution) in the late growth stage mainly due to the alterations in leaf geometry with the change in leaf inclination angle along a more horizontal axis after flowering, while in contrast, values of F were less than 0.5 in the early growth stage mainly due to the distribution bias of leaves after transplanting. Seasonal variation in F during different cropping seasons could commonly be expressed as a function of developmental stage (DVS). Using this function, τ and ref could be estimated with more accuracy. The proposed radiation model and function is expected to be applicable in more accurate evaluation of solar radiation, dry matter production and soil/water temperature in paddy fields.

The Effect of Water Deficit in Typical Soil Types on the Yield and Water Requirement of Soybean (Glycine max [L.] Merr.) in Indonesia

Abstract: An experiment was conducted with the objective to investigate the influence of available water deficit in typical soil types on the yield and crop water requirement of soybeans in Indonesia. This research was conducted in a plastic greenhouse of the University of Lampung from June to August 2005. A factorial experiment was arranged in randomized block design with three replications. The soil type (S) was the first factor with two different soil types, Ultisol (S1), and Latosol (S2). Water deficit (D) was the second factor with five levels including D1 (0-20%), D2 (20-40%), D3 (40-60%), D4 (60-80%), and D5 (80-100%) of water deficit from the total available water (TAW). For example, D1 (0-20%) meant that water was given to maintain the available water depletion between 0% and 20% of TAW in the root zone. Yield under full irrigation in Ultisol (21.3 g/pot) was 2.3 times as much as in Latosol (9.3 g/pot). Yield efficiency (the ratio of yield to crop water requirement) in Ultisol was the greatest under deficit irrigation of 30% of available water deficit (0.0083 g/g), which was 1.26 times as much as under full irrigation (0.0066 g/g). However, yield efficiency of Latosol was the greatest under full irrigation (0.0049 g/g). Therefore, yield efficiency of soybean in Ultisol was 1.8 times as much as in Latosol.

Performance of Grass Strips for Sediment Control in Okinawa

Abstract: Reddish fine sediment runoff from upland fields has been one of the causes of coastal environmental pollution in Okinawa, Japan. Planting grass strips is a well-known measure to reduce runoff of non-point-source pollutants from agricultural fields. In this study, we investigated the performance of a centipede grass (Eremochloa ophiuroides (Munro) Hack.) strip for reducing sediment runoff from an upland field in Okinawa, focusing on strip length and sediment aggregate size as factors affecting performance. Field experiments were conducted in field plots with a 4.0-m by 31.5-m bare source area on a Kunigami-Maji soil using three strip lengths (0.5, 1.5 and 3.0 m) under natural conditions. The sediment removal efficiencies were 24% for the 0.5-m strip, 36 to 54% for the 1.5-m strip and 73% for the 3.0-m strip. The strips trapped well the sediment aggregates larger than 0.02 mm in diameter, regardless of strip length. The longer strip trapped more aggregates of the 0.002-0.02-mm size class, which were dominant in the eroded sediment runoff from the plots. The strips poorly trapped aggregates smaller than 0.002 mm. The sediment trapping resulted primarily from deposition of sediment due to slowdown of surface flow.

Fitness Characters in Parasexual Recombinants of the Rice Blast Fungus, Pyricularia oryzae

Abstract: We examined the fitness characters in parasexual recombinants derived from cocultures of two isolates, NAO-02 (race 133.1) and TH77-1 (race 047.0), of the rice blast fungus, Pyricularia oryzae, in liquid yeast extract medium. The cocultured isolates were transferred to oatmeal agar to produce a conidial inoculum. Then, the conidial suspension was sprayed on the japonica rice cultivar Akiyutaka, which has two resistance genes to rice blast: Pik and Piz. Three pathogenic variants were isolated from the typical leaf blast lesions that were subsequently produced. We used randomly amplified polymorphic DNA (RAPD) to examine whether the variants were derived from parasexual recombination between the parents. Eleven RAPDs indicated that the variants possessed genomic DNA from both parents. After inoculating Akiyutaka 7 times in succession, the variants maintained their original pathogenicity. The parasexual recombinants produced more conidia and larger lesions on the host than did parent TH77-1, but fewer conidia and smaller lesions than parent NAO-02. Disease development on plants inoculated with either variant or a parental isolate was also midway between the disease caused by each of the parents in a field containing a single cultivar, but the variant caused the most severe disease in a plot with a mixture of cultivars. These results suggest that parasexual recombination produces variation in fitness.

Effects of Different Kinds of Fertilizer and Application Methods on δ15N Values of Tomato

Abstract: Effects of different kinds of fertilizer and application methods on tomato yields and inorganic nutrient contents were investigated. The contribution of nitrogen usage to tomato production for each fertilizer application was also estimated by the stable isotope ratio of nitrogen. LSR (low sulfate slow-release fertilizer, LSR plot), daily application of liquid OK-F-1 fertilizer (OK-F-1 plot) and PEL (manure pellet fertilizer, PEL plot) yielded most among the eight different treatments. Fruit quality as measured by nitrogen content (related to amino acid content) was higher in the OK-F-1 treatment. In the conventional fertilization of mixing fertilizer in soil, roots absorbed soil nitrogen which affected the δ 15 N values of fruits, while in the daily application of liquid fertilizer (fertigation) there was little observed influence of soil nitrogen on the δ 15 N values of the upper parts of tomato. These results suggested that fertigation is an effective fertilization method which preserved soil nitrogen.

Use of Self-Compatibility and Modifier Genes for Breeding and Genetic Analysis in Common Buckwheat ( Fagopyrum esculentum )

Abstract: Common buckwheat plants have heteromorphic self-incompatibility. Using two self-fertilizing lines, we revealed that there are two distinct systems of sell-compatibility, one using a self-compatible allele, S', the other using modifier genes located outside the S locus and suppressing the functions of the S-locus genes. S h appears to have been produced by recombination in the S supergene (gi s I P PA/gi S I p PA), in which each gene is functional. The modifier genes control the intensity of self-incompatibility and have three distinctive features: (1) Pollen shows cross-compatibility with styles of all flower types, although the compatibility is influenced by the genetic background of those plants. (2) Flower morphology of F 1 plants is controlled by the genotype of the S locus. (3) F 1 plants show high self-compatibility, although the level of self-compatibility is influenced by genetic background. The use of these genes for buckwheat breeding is discussed.

CFD Modeling to Improve the Design of a Fog System for Cooling Greenhouses

Abstract: A CFD model was developed to simulate the air temperature and relative humidity distribution in greenhouses adopting fog-cooling systems using FLUENT. The developed model was validated using the data from a fog-cooling experiment in a single-span greenhouse without plants. The measured and simulated air temperatures varied from 0.1 to 1.4°C and the differences of relative humidity varied 0.3-6.0%. The validated model was then used to evaluate the design of a fog-cooling system in a multi-span glasshouse. The optimal system design was determined in terms of the cooling efficiency and the special uniformity of air temperature and relative humidity. The simulations demonstrated that the best performance of the cooling system occurred when the fog nozzles were located at the height of 2.3 m above the floor and at a distance of 1.9 m from the sidewalls with uniform row-to-row spacing of 3.7 m. The most effective location of the nozzles was within the air entry from the sidewall ventilator inlets of the greenhouse. However, it was important not to wet the sidewalls with the fog. This study suggested that the CFD model developed could be a useful tool to design and evaluate the fog-cooling systems in greenhouses with various configurations.

Nipah Virus Survey of Flying Foxes in Malaysia

Abstract: An outbreak of Nipah virus infection occurred in 1998 in Malaysia in which a total of more than 1 million pigs were culled and 109 people died from this disease. Samples were collected from frugivorous bats living in Malaysia that were considered to be a natural reservoir of Nipah virus. There were two kinds of fruit bats, the so-called flying fox and the small fruit bat. Samples were collected from small fruit bats and flying foxes caught by mist net traps. No antibody and no Nipah virus were detected from the samples of small fruit bat. However, an average 18% and 63% positive for antibody were detected from the samples of flying foxes living in the islands (Island flying fox) and peninsula of Malaysia (Malayan flying fox) respectively. Nipah virus was not isolated from either of the flying foxes. However, Nipah virus gene was detected from Malayan flying fox by real-time PCR. Reovirus like virus and other unknown viruses were isolated from Malayan flying foxes. From these results, flying fox was an important natural reservoir of Nipah virus and especially Malayan flying fox was considered to be more important as a natural reservoir.

Comparative Study on Energy and Nitrogen Metabolism of Brahman Cattle and Sheep Given Ruzi Grass Hay with Different Levels of Soybean Meal

Abstract: Metabolism trials were conducted on six wethers and four Brahman steers given Ruzi grass hay with different levels of soybean meal in order to compare the effects of protein levels on energy and nitrogen balances, and fiber digestion between the two animal species. Crude protein (CP) contents in four dietary treatments were 3.4%, 6.9%, 10.4%, and 13.9% with the different levels of soybean meal supplement. Digestibilities of crude fiber, neutral detergent fiber and acid detergent fiber were greatly improved in sheep by the supplement of soybean meal until the CP content in the whole ration reached 10%. The difference was more than 10 units in each fiber fraction. While in cattle, fiber fraction digestibilities in the animals given Ruzi grass hay without soybean meal supplement were relatively high. The values were then improved by the smallest amount of supplement (6.9% CP). Beyond this level, there was no effect of the supplement. Although digestibility of CP was lower in sheep when no protein supplement was given, it was higher in sheep when high protein diets were given (10.4 and 13.9% CP). The total digestible nutrient and digestible energy contents well represented overall features of the differences in nutrient digestibilities between sheep and cattle. With lower levels of soybean meal supplement, these values were lower in sheep than in cattle. While, with higher levels of the supplement, there was no difference in the values between the animals. Sheep are often studied as a model animal for cattle in order to examine nutritive value of feed resources. It was suggested in the design of feeding trials using sheep, that CP content of whole ration, in which a target feed resource is included, should be more than 10%.

Immunohistochemical Study of Lymphomas of Abdominal Cavity Origin in Two Cows with Bovine Leukemia Virus

Abstract: Lymphoid neoplasms of abdominal cavity origin were found in two cows infected with bovine leukemia virus (BLV). Case 1 was a 3-year-old Japanese Black cow affected with a B-1 B cell lymphoma. Case 2 was a 14-year-old Japanese Black cow that developed a γδ T cell lymphoma. Immunohistochemically, CD79a-positive lymphoma cells were observed in case 1, whereas CD3-, WC1- or perforin-positive ones were seen in case 2. Despite the expression of CD5 in both lymphomas, the reactivity was surface or cytoplasmic in case 1 and surface membrane in case 2. Erythrophagia by tumor cells of both cases was considered to be due to the fact that their normal counterparts were more primitive forms than conventional lymphocytes.

Characteristics of the adsorption of dissolved organic matter by charcoals carbonized at different temperatures

Abstract: We investigated the adsorptive volume and rate, adsorption isotherm, and the pH dependence of charcoals obtained from carbonizing cedar (Cryptomeria japonica D. Don) wood chips at various temperatures; these charcoals were used to remove dissolved organic matter (DOM) that was eluted from rice-straw. In order to confirm the adsorption characteristics, three experiments were carried out in the laboratory. The adsorption characteristics were estimated by determining the total organic carbon (TOC) concentration, adsorption isotherm and the pH in solutions. Results showed that the trend of DOM adsorption effect by charcoals was categorized into two groups: group-1 (charcoals carbonized at less than 750°C) and group-2 (charcoals carbonized at more than 850°C). Group-2 adsorbed a greater amount of DOM and at a more rapid rate than group-1. The adsorption isotherm for group-2 followed the Freundlich model. In particular, the Freundlich constants, K and 1/N, for the charcoal carbonized at 1,050°C indicated that this charcoal had higher adsorption volume and adsorption intensity for DOM than other charcoals. Furthermore, this charcoal adsorbed TOC irrespective of the initial pH value in sample water. This indicated that charcoals carbonized at 1,050°C could change the pH value of the water contaminated with acid to neutral.

Genetic and breeding analysis of blast resistance in elite indica-type rice (Oryza sativa L.) bred in international rice research institute

Abstract: Using a new differential system which is based on the gene-for-gene relationship between rice resistance genes and blast races, at least seven kinds of genes, Pi20, Pita, Pik‡ (one of the Pik allele genes except for Pik-s), Pik-s, Pib, Piz-t, and Pii or Pi3, were estimated in 42 International Rice Research Institute (IRRI)-bred rice (Oryza sativa L.) varieties using 14 blast isolates from the Philippines. Moreover, genetic analyses based on the segregation of BC 1 F 2 populations derived from the crosses between IRRI varieties and susceptible rice, C039, as recurrent parents, and allelism tests with differential varieties, were performed to identify and confirm these estimated genes using 10 varieties among them. A total of 7 genes, Pi20, Pita, Pik‡, Pia, Pib, Pik-s, and Piz-t, were identified. In some varieties, the four genes Pia, Pib, Pik-s, and Piz-t that were not estimated by reaction patterns in the previous analysis, were identified by these genetic analyses. Among the genes identified, Pib and Pik alleles (Pik-s or Pik‡) were considered widely distributed.

Susceptibility of Fish Species Cultured in Mangrove Brackish Area to Piscine Nodavirus

Abstract: Susceptibility of orange-spotted grouper Epinephelus coioides, Asian sea bass Lates calcarifer, mangrove red snapper Lutjanus argentimaculatus, milkfish Chanos chanos, and rabbitfish Siganus guttatus to piscine nodavirus from orange-spotted grouper was studied by experimental infection. The fish were intraperitoneally injected with 0.05 mL of the filtrate homogenate of infected organs from diseased grouper at 10 6.8 , 10 5 8 or 10 4 .TCID 50 /fish, while the control group received 0.05 mL of Hanks' balanced salt solution. Clinical signs such as lethargy, anorexia and darkened pigmentation were observed in the orange-spotted grouper, Asian sea bass, mangrove red snapper, and milkfish injected with high and medium doses of the homogenate. Although no or little mortality occurred in the experimentally-infected fish 10 days post-inoculation, viral nervous necrosis specific lesions such as severe necrosis and vacuolation in the brain and retina were produced in these four fish species. The virus was reisolated in SSN-1 cells inoculated with the filtrated tissue homogenate of survivors in all doses for all four fish species. However, in the experimentally infected rabbitfish no histological lesion was observed, and no virus was reisolated. These results indicate that grouper, sea bass, mangrove red snapper, and milkfish are susceptible to the piscine nodavirus isolated from diseased grouper.

Characterization of Cucumber Cultivars by Mechanical Stress Distributions during the Compression Process

Abstract: Firm, crispy and crunchy texture is an important factor of plant-based foods. Pre- and post- failure processes of cucumber cultivars were examined to explore the mechanical properties that determine cultivar-specific crispy and crunchy texture. Spatial distribution of mechanical properties, which can be a very important characteristic in relation to food textural quality, was visualized and characterized for the mechanically complex and heterogeneous structure of cucumber fruits. A multiple-point sheet sensor system, which shows time series of spatial stress distribution on a sample, successively demonstrated the characteristics of the stress distribution in each tissue of cucumbers and its differences among cultivars during the prefailure process of compression tests. For the postfailure process, it was confirmed how fractures occur, as either a major global fracture event or a number of sequential small local fractures. The two-dimensional information about postfailure events enabled us to relate the structural fracture phenomenon to the force-strain property of each cultivar. This technique is applicable to other food materials to explore the relationships among their mechanical properties, structure, and texture.

Application of Acidified Sodium Chlorite Prewashing Treatment to Improve the Food Hygiene of Lightly Fermented Vegetables

Abstract: Sanitation efficacy of prewashing with acidified sodium chlorite (ASC) for the production of lightly fermented Chinese cabbage was evaluated. The treatment of raw cut Chinese cabbage with ASC for 15 min significantly reduced the level of pathogens without causing apparent changes in color. The population of natural microflora on the leaves was reduced by about 2.0 log CFU/g just after washing with ASC, which is significantly better than what was achieved with a control distilled water wash (P < 0.05). In a control experiment, viable aerobic bacteria increased gradually when incubated at 10°C, however, ASC washed cut Chinese cabbage maintained a lower microbial level. The treatment of cut Chinese cabbage with ASC reduced the population of artificially inoculated Escherichia coli 0157:1-17, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes by 2.4 log CFU/g. The sanitation efficacy of ASC was 1.6 log CFU/g higher than that of distilled water washing. The viable cell counts of all pathogenic bacteria tested remained constant during 8 days of storage at 10°C for both washing treatments with the exception of L. monocytogenes. In the case of L. monocytogenes, the viable cell counts after ASC washing treatment increased gradually with time. No significant difference in color, odor, taste, and texture change in raw leaves or fermented ones was observed with an ASC wash compared to a distilled water wash. These results suggested that prewashing with ASC could control the bacterial growth in lightly fermented Chinese cabbage without changing its quality.

Localization of Quantitative Trait Loci for Yield Components in a Cross Oriental × Occidental Barley Cultivar (Hordeum vulgare L.)

Abstract: Ninety-nine recombinant inbred lines (RILs) were grown for three years and yield components were evaluated. Composite interval mapping showed that the vrs1 and uzu genes consistently controlled grain weight per plant. The analyses also identified a new QTL of kernel length on chromosome 3H, a QTL for kernel width on chromosome 6H and a QTL for thousand-kernel weight on chromosome 2H. The QTL generated in this study may be a useful target for marker-assisted selection in breeding programs.

Studies on Biocontrol of Air-borne Plant Disease by a Filamentous Fungus Producing Antifungal Volatiles

Abstract: Microorganisms isolated from wheat leaf surfaces were screened for inhibition of wheat powdery mildew. A new screening method, in which wheat leaves were inoculated with Blumeria graminis f. sp. tritici and incubated with the cultured microorganisms under non-contact conditions, was developed in our study. Among these strains, a fungus designated as Kyu-W63 had an especially strong inhibitory effect. Kyu-W63 had a strong aromatic odor when being cultured. Nuclear magnetic resonance analysis revealed that Kyu-W63 produced two types of volatile substances, 5-pentyl-2-furaldehyde and 5-(4-pentenyl)-2-furaldehyde. Although the two are known to be nematicidal substances, the antifungal activity of 5-(4-pentenyl)-2-furaldehyde is first confirmed in our study. In contrast, 5-pentyl-2-furaldehyde was found to have strong suppression activities to various fungal species in this study, although it has been reported to suppress the growth of yeast, Nematospora coryli. Strain Kyu-W63 completely agreed with Irpex lacteus in the rDNA internal transcribed spacer (ITS) sequences, and strain Kyu-W63 was inferred to be I. lacteus. Biocontrol of parsley powdery mildew, caused by Oidium sp., was examined using a filamentous fungus, Kyu-W63 that produces antifungal volatiles, for 3 years under greenhouse conditions. Kyu-W63 treatment significantly inhibited disease severity compared to control plots. In addition, Kyu-W63 suppressed other harmful fungi such as Penicillium sp. and Aspergillus sp. which are plant pathogens or human allergens existing in the environment.

Tree Biomass of Planted Forests in the Tropical Dry Climatic Zone: Values in the Tropical Dry Climatic Zones of the Union of Myanmar and the Eastern Part of Sumba Island in the Republic of Indonesia

Abstract: We measured the values for biomass and mean annual biomass increment (MAI) of planted forests in two parts of the Tropical Dry climatic zone (mean annual precipitation [MAP] < 1,000 mm) and in one site adjacent to one of the two parts and outside the Tropical Dry climatic zone to provide a comparison value for wet forests in the same region. MAI values of four planted forests averaged 2.60 (±1.61 SD) Mg ha -1 y -1 at a MAP of 637 mm in the central dry zone of Myanmar. The MAI of exotic fast-growing tree species (Eucalyptus camaldulensis Dehn.) did not differ significantly from those of three native non-fast-growing tree species in the central dry zone of Myanmar. MAI values appeared to be lower on land with a high gravel content in the soil or with a higher degree of erosion. In the eastern part of Sumba Island in Indonesia, MAI of planted Tectona grandis L. forest equaled 3.76 Mg ha -1 y -1 at a MAP of 500 mm and 4.49 Mg ha -1 y -1 at a MAP of 1,500 mm. A Leucaena leucocephala de Wit stand produced a higher MAI (9.62 Mg ha -1 y -1 ) at a MAP of 500 mm. The MAI values for fast-growing tree species that we measured or collected in the Tropical Dry climatic zone were less than 20% of those recorded in the Tropical Moist and Tropical Wet climatic zones and about one-third the value for forests of non-fast-growing tree species. Accordingly, fast-growing tree species may not be capable of achieving their fast growth rates under the Tropical Dry climate. This information will be useful in developing land-use programs based on plantation forestry in dry forest areas.

Hypergranular γδ T-cell lymphoma in a heifer

Abstract: Lymphoma with large granular lymphocyte (LGL) morphology in a heifer is described. The most noticeable macroscopic finding was neoplastic involvement of the skin, mucosae of the alimentary tract, urinary bladder, and uterus. Histologically, lymphoma cells with large numbers of fine eosinophilic granules predominated in the neoplastic tissue, and the granules were positive for perforin. Surface CD3, CD5 or WC1 was expressed by some neoplastic cells. In addition to the epitheliotropism that is a feature of ordinary yδ T-cell lymphoma, the neoplastic cells showed angiodestruction and erythrophagocytosis. These phenomena were thought to result from marked activation of neoplastic yδ T-cells. The present lymphoma was distinct from the previously reported bovine NK-like T-cell lymphoma in its tissue distribution, cytomorphology, cytochemistry, and immunophenotype. Since this lymphoma was regarded as a cytologic variant of γδ T-cell lymphoma, the term hypergranular γδ T-cell lymphoma seemed to be more appropriate than γδ T-cell LGL lymphoma.

Influence of Irrigation Level, Growth Stages and Cultivars on Leaf Gas Exchange Characteristics in Snap Bean (Phaseolus vulgaris) under Subtropical Environment

Abstract: This study was conducted to clarify the genotypic differences in diurnal variations in leaf gas exchange characteristics and the effect of irrigation levels, growth stages and cultivars on leaf water status, gas exchange characteristics and seed yields. Associations of leaf water status with photosynthetic rate in five cultivars of snap bean were also determined. Diurnally, leaf gas exchange was highest at 9:30 h, decreased but remained constant between 11:30 to 14:15 h and then decreased up to 16:15 h. Cultivars Haibushi and Ishigaki-2 displayed higher photosynthetic activity throughout the day. The cultivars having higher seed yield showed higher leaf conductance, transpiration rate and leaf vapor pressure deficit at floral bud initiation stage and higher leaf water potential and relative water content in the irrigated plot at flowering stage. The cultivars with slow development of leaf water deficit displayed higher rates of photosynthesis and vice versa. The results showed that midday hours showed large genotypic differences in leaf gas exchange characteristics with constancy of photosynthetically active radiation. Therefore, screening of snap bean cultivars can be made during midday hours for gas exchange characteristics irrespective of growth stages and irrigation levels. Cultivars maintaining higher leaf water content with increasing water deficit can be selected for higher rates of photosynthesis.

Oviposition and Immature Development of the Parasitoid Fly Compsilura concinnata (Meigen) (Diptera: Tachinidae)

Abstract: Compsilura concinnata is a gregarious tachinid which lays eggs directly into a host larva with a sickle-shaped ovipositor. The oviposition and immature development of C. concinnata was examined using the noctuid moth Mythimna separata as a host. C. concinnata females usually laid one egg per single ovipositional attack, but occasionally laid more than one egg at a time. Also, the females often deposited no eggs in both moving and non-moving hosts, suggesting that this imperfect oviposition was not caused by the defense behaviour of the host. Successful development from egg to adult was obtained within a temperature range of 15.0-27.5°C. At 30°C, this fly could pupariate but failed to emerge as an adult. The developmental time from oviposition to adult emergence decreased with rising temperature. The lower developmental threshold from oviposition to adult emergence was 7.7°C for females and 8.7°C for males. The total effective temperature from oviposition to adult emergence was 404.4 degree-days for females and 342.1 degree-days for males.

Emergence, Oviposition and Larval Behaviors in the Teak Beehole Borer (Xyleutes ceramica Wlk.) in Northern Thailand (Lepidoptera: Cossidae)

Abstract: Adult emergence, oviposition and larval behaviors of the teak beehole borer (Xyleutes ceramica), a major pest moth of teak, were studied in the laboratory and the plantations in northern Thailand. Adult moths emerged mostly in March prior to the beginning of the rainy season. Females laid the greatest number of eggs on the first night after mating. Cumulative percentage of deposited eggs reached 79.2% on the 2nd night. The number of deposited eggs, which was estimated from weight, was 12,489 per female ranging from 3,666 to 21,094. A highly significant linear relationship existed between the numbers of eggs and the weight of an egg batch. Mated female longevity was 7 days on average. Eggs were laid in a mass mostly beneath the scales of bark of teak trunks in the field. An ovipositing female staying on a young teak tree in nature was also observed dropping her eggs to the ground. This is the first record of the finding of eggs and the oviposition behaviors of the moth in the field. Experimentally released larvae showed positive geotaxis both on the cut logs and on the living teak trunks. On the living teak trunks, larvae frequently changed their boring sites before June, but in early July, 37.5% of surviving larvae remained in the same boring sites as in the previous month and 78.6% in early August. All larvae settled down in particular boring sites in September. Control tactics for the teak beehole borer were also discussed in view of the oviposition behaviors.