Japan Agricultural Research Quarterly: JARQ
Online ISSN : 2185-8896
Print ISSN : 0021-3551
ISSN-L : 0021-3551
最新号
選択された号の論文の11件中1~11を表示しています
REVIEWS
Crop Science
  • Toshikazu KURANOUCHI, Mio NISHINAKA, Akiko TAKADA, Toru KUMAGAI, Makot ...
    原稿種別: review-article
    2020 年 54 巻 1 号 p. 1-6
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    Sweetpotato is among the most important crops originating from the tropics. Low soil temperature inhibits the thickening of sweetpotato roots. The growth of ordinary sweetpotato cultivars is thought to be limited below 15-16°C. In Japan, commercial sweetpotato production has recently been attempted in cool areas, in addition to warm areas, and a device for testing low-temperature tolerance in sweetpotato has been developed. In this system, containers fabricated from aluminum boards were filled with horticultural soil and set in a cooled water tank. Sweetpotatoes were cultivated at a soil temperature of 17°C for three weeks. Some lines exhibiting slight growth in low soil temperature conditions (14°C) were successfully bred, and achieved high yield from early planting in fields. It is important to breed low-temperature-tolerant sweetpotato lines achieving both high yield and high quality, in order to expand the crop’s cultivation range.

Animal Science
  • Misaki KOJIMA
    原稿種別: review-article
    2020 年 54 巻 1 号 p. 7-12
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    Drug metabolizing enzymes (DMEs) that exist primarily in the liver are one of the critical factors determining the susceptibility of animals and humans to xenobiotics such as drugs, and also metabolize steroid hormones and other endogenous compounds. Although sex and/or species differences in the constitutive gene expression levels of hepatic DMEs have been reported to date, the causes of such differences have yet to be completely explained. The DME genes of pigs have recently been identified. Because pigs are valuable animals for human pharmacological and toxicological studies, research on the gene expression of DMEs in pigs is being promoted. We have found sex and/or breed differences in the constitutive gene expression of hepatic DMEs, including cytochrome P450s, sulfotransferases, and UDP-glucuronosyltransferases, in Meishan and Landrace pigs. We propose that physiological serum testosterone level is a critical host factor producing these differences. This review discusses the testosterone-mediated gene expression of hepatic DMEs.

ARTICLES
Biotechnology
  • Satoshi SUZUKI, Ken-ichi KUSUMOTO
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 13-20
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    The production process of such traditional Japanese fermented foods as miso, shoyu and sake using Aspergillus oryzae has been highly optimized over a long history. However, new technology is needed to achieve further improvements in productivity or production efficiency. Light affects the gene expression and metabolic pathways of fungi. Thus, the development of technology that takes advantage of the light response of A. oryzae is important. In a previous study, we found that A. oryzae strains RIB40 and RIB1187 showed opposing manners of growth and conidiation in response to light. To elucidate the effect of light on genome-wide gene expression for both strains, we conducted transcriptome analysis by RNA sequencing. We also identified 453 differentially expressed genes (DEGs) between both strains by bioinformatic analysis. Of these 453 DEGs, we identified a total of 67 light-responsive DEGs between RIB40 and RIB1187. We also analyzed the expression patterns of fermentation-related digestive enzyme genes.

Agricultural Environment
  • Haruhiko INOUE, Akiko OKADA, Shigeru UENOSONO, Motofumi SUZUKI, Tomoya ...
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 21-29
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    An epidemiological investigation was conducted in the Amami Islands of Kagoshima Prefecture, Japan, to determine the pathogenesis of citrus greening disease, also known as citrus Huanglongbing (HLB) disease, especially in relation to trace metal nutrition. We sampled 11 sites with acidic soil and 46 sites with alkaline soil in private gardens on the islands of Tokunoshima and Amami Oshima. At the acidic sites, no HLB-infected citrus trees were detected using PCR amplification. In the private gardens, 38.6% of the trees tested were infected with HLB disease. By comparing soil pH values in those private gardens, we found that HLB infection was related to soil pH. Among trees growing in alkaline soil, 47.8% were infected, whereas none of the trees growing in acidic soil in the private gardens were infected. When comparing a distribution map of HLB-diseased trees with a soil component map of the five Amami Islands, HLB disease was not detected in acidic soil, but the distribution of HLB-diseased trees was similar to the location of alkaline soil. Microelement analysis of leaves from trees grown in alkaline soil revealed significantly lower levels of manganese (71.9%), copper (70.1%), zinc (52.3%), and iron (40.9%) compared with the leaves from trees grown in acidic soil. These results suggest that HLB disease prefers citrus growing in alkaline soil where the concentrations of Fe and Zn nutrients are reduced.

  • Naruo MATSUMOTO, Saythong OUDTHACHID, Phanthasin KHANTHAVONG, Amphay S ...
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 31-40
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    The maize cultivation area in Lao PDR has increased since 2004, mostly without the use of fertilizer. For sustainable maize production, maintaining soil fertility is essential. This study aims to clarify nutrient removal by maize cultivation in fields located in the districts of Kenethao and Paklai in Xayabury Province—the main maize production area in Lao PDR. Field surveys were conducted at 27 plots in nine farmer fields in 2013 to measure maize production, collect plant samples for analyzing nutrient uptake and soil samples for analyzing nutrient stock in the soil, and interview farmers about cultivation practices and field history. N, P, and K removal by harvest from the fields totaled 51.7, 7.5, and 14.2 kg ha−1, respectively. Nutrient stock in the soil surface layer at 0-20 cm deep was 2980 kg ha−1 as total N, 10.1 kg ha−1 as available P, and 233 kg ha−1 as exchangeable K. N and K stocks in the soil were sufficient compared with N and K removal in maize at harvest, although available P in the soil was similar in amount compared to P removal by harvest. Most farmers did not apply any fertilizer for maize cultivation. The N, P, and K balances in the fields were estimated at −47.6, −7.4, and −14.3 kg ha−1, respectively, without fertilizer input, and were improved to −25.6, +1.4, and +5.5 kg ha−1, respectively, by applying chemical fertilizer.

Food
  • Junichiro MARUI, Sirinan SHOMPOOSANG, Wanchai PANTHAVEE
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 41-45
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    Khanom jeen is a traditional Thai noodle made from fermented rice flour. It is produced and consumed throughout Thailand. Noodle products in local markets usually maintain their quality without rotting for a few days at ambient temperature. However, producers occasionally suffer the problem of noodle liquefaction. Severe liquefaction occurs unpredictably within a day at the production site. In the present study, liquefaction was induced by treating noodles with McIlvaine buffer at pH 6.0 and pH 8.0, but was not induced when the noodles were treated with distilled water, McIlvaine buffers at pH 4.0, or 1% sodium lactate buffer at pH 4.0. This pH-induced liquefaction was suppressed when chloramphenicol was added to the buffers, suggesting that this phenomenon was associated with bacterial growth. An increase in reducing sugar, presumably derived from oligosaccharides by starch digestion in the noodles, was observed in accordance with α-amylase production under the liquefaction-inducing conditions. Different starch-digesting enzymes in the liquefaction process were observed using zymography. The noodles used in this study contained about 0.03% lactic acid. Maintaining the acidic environment in noodles to prevent bacterial digestion of starch should help retain the khanom jeen noodle structure.

  • Yasuhiro INATSU, Arranee CHOTIKO, Chiraporn ANANCHAIPATTANA
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 47-51
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    Fermented soybeans without salt (“Tua Nao”) are commonly produced and consumed in northern areas of Lao PDR and Thailand. Contamination of pathogenic Bacillus (B.) cereus during its production may cause toxic food poisoning. To evaluate the practical risk, we purchased 10 Lao and 23 Thai Tua Nao products from local markets in the northern areas of both countries, and then confirmed B. cereus contamination. Nine (90%) of the 10 Lao samples and 18 (78%) of the 23 Thai samples contained B. cereus. Two of the Thai isolates produced diarrheal enterotoxin confirmed by a reversed passive latex agglutination test (an immunological method). Emetic toxin coding gene (crs) was detected from two Lao isolates by the PCR method. These five (potential) toxin-producing B. cereus strains exhibited different random amplified polymorphic DNA (RAPD)-PCR patterns. Improvement of general hygiene control and the use of starter culture are considered necessary to prevent foodborne illnesses caused by B. cereus in fermented soybean produced in these countries.

  • Kaori FUJITA, Philavanh BOUTSAVATH, Xaypunya MAHATHILATH, Masataka SAI ...
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 53-61
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    Common freshwater food fishes such as the Walking Catfish (Clarias batrachus), Broadhead Catfish (Clarias macrocephalus), Climbing Perch (Anabas testudineus), and Striped Snakehead (Channa striata) are widely consumed in Southeast Asia, including Lao PDR. Quantitative differences in the nutritional value of these fishes were evaluated by seasons and sizes as essential nutritional information toward improving the nutritional status of each country’s residents. Size (weight and total length) and proximate composition (moisture, protein, fat, and ash contents) of the above fishes were measured quarterly over a year, with the sample fishes being separated into three size groups (large, medium, and small). Fishes of the “small” group tended to have higher moisture, protein, and ash contents than those of the “large” group across the species. In contrast, the “large” group tended to have higher fat content than those of the “small” group. In addition, seasonal fluctuations of fat content were observed in three species except the Walking Catfish, and are considered to be relevant to the reproductive cycles of each species. All the results obtained here are essential information for informing consumers of the nutritional value of the above species by species and by seasons/sizes.

Social Science
  • Tatsuji KOIZUMI, Gen FURUHASHI
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 63-91
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    Rice is not strictly a homogeneous commodity, with the international rice market largely divided into the japonica and indica rice markets. Both follow different market structures and the international prices of japonica and indica show different trends. We projected and simulated the future global japonica and indica rice markets under climate change in the long term, using a partial equilibrium model. The Rice Economy Climate Change (RECC) model thus developed covers the japonica and indica rice markets in 24 countries and regions as the entire world rice market. The simulation results suggest that the international price of japonica rice will be more volatile than that of indica rice, and that both price indicators will exhibit different trends due to the impact of long-term climate change.

Animal Science
  • Manabu YAMAGUCHI, Akira WATANABE, Naoki TAKENOUCHI, Hiroyuki SUZUKI, M ...
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 93-100
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    The growth characteristics of five male Japanese Black calves that were produced by embryo transfer to, born from, and nursed by Japanese Shorthorn surrogate dams (BS-group) were compared with those of five male Japanese Shorthorn calves that were delivered from dams of the same breed after natural mating (SS-group). The birth weights of the BS-group calves were lower (P < 0.01) than those of the SS-group calves. During the first two months, the daily weight gain of the SS-group calves was greater (P < 0.05) than that of the BS-group calves. However, between the third and fourth months, the daily weight gain of the BS-group calves was greater (P > 0.05). During the first two months, the chest girth was smaller (P < 0.05) in the BS-group calves than in the SS-group calves, but was similar in both groups by the age of four months. Although the gains in chest depth, body length, and withers height of the BS-group calves were inferior to those of the SS-group calves during the first two months, these gains were all superior to those of the SS-group calves during the next two months. Trends in age-related changes in plasma total cholesterol concentrations significantly differed between both groups. The SS-group dams lost much more weight during early lactation than did the BS-group dams (P > 0.05). No difference was observed in the blood components of the dams in either group. In summary, the BS-group calves were relatively small at birth, and their growth performance was inferior to that of the SS-group calves during the first two months. At around two months of age, the Japanese Black embryo-transfer calves began to suckle larger amounts of milk from their surrogate dams and showed rapid growth that was comparable to that of larger framed Japanese Shorthorn calves.

  • Zhe GONG, Kensuke KAWAMURA, Naoto ISHIKAWA, Masakazu GOTO, Wulan TUYA, ...
    原稿種別: research-article
    2020 年 54 巻 1 号 p. 101-112
    発行日: 2020/01/01
    公開日: 2020/02/14
    ジャーナル フリー

    To assess the dynamics of vegetation growth and phenology in the Inner Mongolia Autonomous Region in China, a time series of Normalized Difference Vegetation Index (NDVI) data from 1983 to 2013, derived from the Advanced Very High-Resolution Radiometer-Vegetation Health Product (AVHRR-VHP), was applied to detect linear trends, seasonal phenology transition dates, and growing seasons. Overall, Inner Mongolia became warmer and drier during the study period. A significant increasing cumulative NDVI trend was found for 30.30% of the total vegetation covered area. The restored area was mainly in the western desert steppe. The degraded area was primarily located in the northeastern meadow and typical steppe regions. However, a severe drought was detected during 1993-2003, when approximately 27.56% of the total vegetation covered area experienced a significant decreasing NDVI trend. The length of the growing season (LOS) during 1983-2013 was shortened due to the delayed start of the growing season (SOS) and advanced timing of the end of the growing season (EOS). However, this trend was reversed during the more recent decade (2003-2013). The phenology was closely associated with climate change, especially precipitation. The variability of vegetation responses to climate change was also assessed, indicating that most types of vegetation had recently recovered and that the restored areas had a varied spatial distribution.

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