Relationship between increment of groundwater level at the beginning of irrigation period and paddy filed area in the Tedori River Alluvial Fan Area, Japan

There are many paddy fields and large amounts of groundwater in the Tedori River Alluvial Fan in Ishikawa Prefecture, Japan. Water infiltration from paddy fields during irrigation may significantly contribute to groundwater recharge. Groundwater recharge is known to be one outcome of paddy farming, and in general is usually related to land use. However, a decreased area of paddy fields because of socioeconomic factors such as urbanization and increasing area of fallow fields has possibly affected the groundwater environment. Evaluation of the quantitative effect of paddy fields on groundwater is necessary for groundwater conservation. This study examined the relationship between differences in the depth of groundwater from just before the irrigation period to just after the first irrigation of paddy fields (increments of groundwater levels) in observation wells and the area of paddy fields around each well. The paddy areas within circular buffer zones, which were delineated at 0.2 km intervals between 0.2 and 2.0 km centered on each observation well, were calculated. A positive relationship was found between the rise in groundwater and the area of paddy field within different buffer zones at most wells. In addition, in the middle or upper part of the fan, the effect of changes in the area of paddy fields surrounding the well on the groundwater level rise was greater than that on the lower part of the fan.     

Black band of Jew’s marrow caused by <Emphasis Type="Italic">Lasiodiplodia theobromae</Emphasis>

Stem rot and wilt of Jew’s marrow (nalta jute, Corchorus olitorius) were found on Is. Okinawa, Okinawa Prefecture, Japan, in March 2000. An anamorphic fungus, Lasiodiplodia theobromae was isolated repeatedly from the diseased plants and demonstrated to cause the disease. We coined the Japanese name “kurogare-byô” of Jew’s marrow for the present disease because it was new to Japan, although it had already been reported in India and Bangladesh as black band of the plant.     

Infection of a group of boar-hunting dogs with Paragonimus westermani in Miyazaki Prefecture, Japan

A 5-year-old male mixed-bred boar-hunting dog with a Plott hound background weighing 23 kg was brought to the Veterinary Teaching Hospital, University of Miyazaki, in October 2002. The dog was diagnosed with active infection with the lung fluke Paragonimus westermani by serological testing and also by detection of parasite eggs in his feces. Subsequent examination of four other dogs working with this dog as a boar-hunting team revealed that all five dogs were infected with P. westermani.     

Regulatory network of hrp gene expression in Xanthomonas oryzae pv. oryzae

Like other plant-pathogenic bacteria, Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, has hrp genes that are indispensable for its virulence. The hrp genes are involved in the construction of the type III secretion (T3S) apparatus, through which dozens of virulence-related proteins, called effectors, are directly secreted into plant cells to suppress and disturb plant immune systems and/or induce plant susceptibility genes. The expression of hrp genes is strictly regulated and induced only in plants and in certain nutrient-poor media. Two proteins, HrpG and HrpX, are known as key regulators for hrp gene expression. Great efforts by many researchers have revealed unexpectedly that, besides HrpG and HrpX, many regulators are involved in this regulation, some of which also regulate the expression of virulence-related genes other than hrp. Moreover, it has been found that HrpG and HrpX regulate not only hrp genes and effector genes but also genes unrelated to the T3S system. These findings suggest that the expression of the hrp gene is orchestrally regulated with other virulence-related genes by a complicated, sophisticated regulatory network in X. oryzae pv. oryzae.     

Influence of riders’ skill on plasma cortisol levels of horses walking on forest and field trekking courses

The aim of this study was to evaluate the influence of rider's skill on the plasma cortisol levels of trekking horses on two courses, walking on field and forest courses (about 4.5 to 5.1 km each). Three riders of different skills did horse trekking (HT) in a tandem line under a fixed order: advanced‐leading, beginner‐second and intermediate‐last. A total of six horses were used and they experienced all positions in both courses; a total of 12 experiments were done. Blood samples were obtained before HT, immediately after and 2 h after HT. As a control, additional blood samples were obtained from the same horses on non‐riding days. Irrespective of the course and the rider's skill, the cortisol level before HT was higher than that of control (P < 0.05). In both courses, the cortisol levels immediately after HT ridden by the advanced rider were higher than that of control (P < 0.05). However, in every case, the cortisol level 2 h after HT was closely similar to the level of the control. Thus, we concluded the stress of trekking horse was not sufficient to disturb the circadian rhythm of the cortisol level, irrespective of the course and the rider's skill.     

Screening of Dried Plant Seed Extracts for Adiponectin Production Activity and Tumor Necrosis Factor-Alpha Inhibitory Activity on 3T3-L1 Adipocytes

To search for dried plant seeds with potent anti-diabetes activity, we conducted a large scale screening for inhibitory activity on tumor necrosis factor-alpha and facilitating activity on adiponectin production in vitro. These activities in 3T3-L1 adipocytes were screened from ethanol extracts of 20 kinds of dried plant seed marketed in Japan. komatsuna (Brassica rapa var. perviridis), common bean (Phaseolus vulgaris L.), qing geng cai (Brassica rapa var. chinensis), green soybean (Glycine max), spinach (Spinacia oleracea L.) and sugar snap pea (Pisum sativum L.) markedly enhanced adiponectin production (11.3 ~ 12.7 ng/ml) but Japanese radish (Raphanus sativus), edible burdock (Arctium lappa L.), bitter melon (Momordica charantia) and broccoli (Brassica oleracea var. italica) did not (0.9 ~ 2.7 ng/ml). All adiponectin-production-enhancing seeds except spinach (2.7 pg/ml) and okra (Abelmoschus esculentus) (6.6 pg/ml) effectively decreased tumor necrosis factor-alpha levels (0.0 pg/ml). We further examined the effects on free radical scavenging activities in the dried seed extracts. Although scavenging activity correlated well with total phenolic content of samples, no correlation was observed with adiponectin production. These results point to the potential of dried seed extracts as a means to modify the activity of tumor necrosis factor-alpha for the adiponectin production.     

Comparison of the glucosinolate-myrosinase systems among daikon (Raphanus sativus, Japanese white radish) varieties

Myrosinase is a cytosolic plant enzyme present in daikon ( Raphanus sativus, Japanese white radish) roots that hydrolyzes 4-methylthio-3-butenyl glucosinolate (MTBGLS) into the natural pungent agent 4-methylthio-3-butenyl isothiocyanate (MTBITC), which possesses antimicrobial, antimutagenic, and anticarcinogenic properties. The concentration of MTBGLS, myrosinase activity, and production of MTBITC in seven daikon varieties (one conventional and six heirlooms) were determined to rank the activity of the glucosinolate-myrosinase system and identify critical factors influencing the production of MTBITC. The six heirloom varieties produced 2.0-11.5 times higher levels of MTBITC as compared to the conventional variety, Aokubi, which is consumed by the present Japanese population. The myrosinase was located exclusively in the outer epidermal layer in Aokubi, and MTBGLS was widely distributed throughout the root tissue. Although the skin is a potentially rich source of myrosinase in Aokubi, the skin is usually peeled off in the current practice of preparing daikon for cooking. New practices are therefore proposed for the preparation of daikon tubers that eliminate the peeling of the skin to avoid removing the enzyme needed to convert MTBGLS to the health-beneficial MTBITC. It is also concluded that the consumption of heirloom daikon varieties in addition to changes in food preparation will optimize the health benefits of daikon.