Effects of Latent Infection of Stock Plants and Abundance of Thrips on the Occurrence of <Emphasis Type="Italic">Tomato spotted wilt virus </Emphasis>in Chrysanthemum Fields

DAS-ELISA proved to be reliable enough to detect a latent infection by Tomato spotted wilt virus (TSWV) in asymptomatic stock plants of chrysanthemum. A high density of Frankliniella occidentalis, the predominant vector, in the presence of latently infected stock plants resulted in a high incidence of disease in the chrysanthemum production field. The incidence of disease was low when the vector thrips were not abundant in spite of the presence of latently infected stock plants. These results suggest that an infestation of the vector thrips causes severe secondary spread of TSWV originating from latently infected stock plants in chrysanthemum production fields. Received 27 July 2001/ Accepted in revised form 27 November 2001     

Strong antiviral activity of heated and hydrated dolomite--preliminary investigation

Heated and hydrated naturally occurring dolomite showed very strong antiviral activity. Infectivity of avian and human influenza, avian infectious bronchitis (coronavirus), Newcastle disease (paramyxovirus) and avian laryngotracheitis (herpesvirus) viruses dropped at least 1,000 fold following contact with the dolomite for five minutes at 4 degrees C. Dolomite is expected to be useful to inhibit the incidence of emerging and re-emerging infectious diseases.     

Effect of ovary lipid of skipjack tuna on rat serum components after stress application

Lipid extracted from the ovary of skipjack tuna by the method that we developed is rich in phospholipid-type docosahexaenoic acid. The ovary lipid of skipjack tuna (OLS) was studied for its anti-stress activity in male Wistar rats, focusing on stress-related blood components: recovery from stress was examined after application of water immersion restraint stress. As a result, serum corticosterone (CORT) secretion was inhibited and decreased rapidly after stress application in rats given OLS compared with control rats. As CORT acts as a glucocorticoid, non-esterified fatty acid (NEFA) is expected to increase by stress application. However, the concentration tended to be lower in rats given OLS than in control rats. With respect to OLS concentration, OLS increased serum dehydroepiandrosterone, secretion concentration-dependently. In addition, as with the recovery study, it tended to inhibit the increase in NEFA. These results indicate that OLS may have an anti-stress activity against acute stress.     

Effects of feeding different levels of concentrate on growth and carcass characteristics in younger Japanese Black cattle

The effects of a higher concentrate feed during the raising period on the growth and carcass of Japanese Black cattle being fattened at a younger age were investigated using three pairs of artificially bred identical twins and three pairs of full‐sibs. The animals were fed the concentrate at 2.4%/day (2.4% group) and 1.2%/day (1.2% group) comparative bodyweight (BW) during the raising period. The BW and subcutaneous fat thickness were measured every month using ultrasonic equipment. The animals were slaughtered at the age of 24 months. The BW of the 2.4% group from the age of 6–10 months appeared to be higher than that of the 1.2% group (P < 0.1). The subcutaneous fat of the 2.4% group from the age of 7–11 months was thicker than that of the 1.2% group (P < 0.1). After those ages, the BW and subcutaneous fat of the two groups did not differ and there was no difference in the carcass characteristics between the two groups. Using a higher concentrate feed during the raising period for younger fattening of Japanese Black cattle influenced growth from the late half of the raising period to the early part of the fattening period.     

Development of X-ray computed tomography for live standing cattle

An X‐ray computed tomography (CT) system for live standing cattle was developed for studying the meat yield, carcass composition and so on. The gantry contained three X‐ray tubes and detectors that corresponded to each X‐ray tube. The system was able to operate while the animal remained standing. The scan area had a diameter of 900 mm. The Musculus longissimus and Musculus trapezius areas, and the back fat thickness in the CT image were evaluated and compared to the actual cross‐section of the carcass using eight cattle. The differences among the muscles, and the subcutaneous and intermuscular fat were easily recognized. The correlation coefficient between the CT image and the actual carcass photograph of the M. longissimus area and the back fat thickness was high (r = 0.84, r = 0.93, P < 0.01). The present study demonstrated that muscle, fat and bone can be clearly imaged from a live standing animal using X‐ray equipment.     

Isolation of myxoviruses from migratory waterfowls in San-in district,western Japan in winters of 1997-2000

Between November 1997 and February 2000, winter migratory waterfowls of several species staying in San-in district, western Japan were surveyed for influenza A virus and paramyxovirus at four stations. A total of 18 influenza A viruses was isolated from 1,404 fecal samples of whistling swans, pintails, mallards, and white-fronted geese. Five different hemagglutinins and eight neuraminidases were identified in the viruses isolated, in 11 different combinations, including H7N8 related to a subtype of a highly pathogenic chicken virus. In 2000, five lentogenic (non-pathogenic) Newcastle disease viruses were also isolated from white-fronted geese. These results suggested that possible precursor viruses for highly pathogenic avian myxoviruses are still brought into Japan by migratory waterfowls. The results also support the contention that continued surveillance of wild waterfowl population should be an integral part of control policies for these serious poultry diseases.     

Estimation of the carcass composition from a cross-section of the rib-loin from crossbred Japanese Black × Limousin F2 cattle by computer image analysis

The carcass composition of crossbred Japanese Black × Limousin F2 cattle was examined in order to find an accurate carcass composition equation. The test animals included 17 steers and 17 heifers. The 28 image measurements from the area encircling the vertical line to the thoracic vertebra and the line from the thoracic vertebra between the sixth and seventh rib‐bones were measured by computer image analysis. The relationships between the 29 parameters that added the carcass left side weight of the animal and the carcass composition were suggested. The carcass composition included muscle weight, muscle ratio, fat weight and fat ratio. The carcass composition from steers was estimated by an equation composed of these three or four parameters (R² = 90.80%, 79.30%, 90.75% and 73.70%, respectively). The selected parameters were measured without cutting the thoracic vertebra. The carcass composition from heifers was estimated by an equation composed of two to four parameters (R² = 96.15%, 90.98%, 93.60% and 88.22%, respectively). The parameters for the estimation of the muscle and fat weight, and muscle and fat ratio are very similar. Furthermore, the equations using the parameters could estimate the carcass composition from the Japanese Black × Limousin cattle resource population.     

In vitro but not in planta encapsidation of Rice gall dwarf virus core particles by the outer capsid P8 protein of Rice dwarf virus expressed in transgenic rice plants

Transencapsidation of the Rice gall dwarf virus (RGDV) inner core by the Rice dwarf virus (RDV) outer capsid P8 protein was examined in vitro and in planta. When RGDV core particles were incubated with an extract from RDV P8-transgenic rice leaf tissue, RDV P8 encapsidated the RGDV core particles to form double-shelled virus-like particles in vitro. In contrast, when RDV P8-transgenic rice plants were inoculated with RGDV, progeny RGDV particles contained RGDV P8 but RDV P8 was not detectable in the virions. No significant differences were found in acquisition by the vector insects and subsequent transmission rates between RGDV infecting nontransgenic rice plants and those infecting RDV P8-transgenic rice plants. These results indicate that mechanisms of and/or requirements for interactions between P8 and the inner core particles of phytoreoviruses differ between in vitro and in planta.     

Genotype by environment interactions (GEIs) for barley grain yield under salt stress condition

Changes in the relative genetic performance of genotypes across environments are referred to as genotype × environment interactions (GEIs). GEIs can affect barley breeding improvement for salt tolerance because it often complicates the evaluation and selection of superior genotypes. The present study evaluated the GEIs over 60 barley genotypes for yield components and grain yield in six salinity environments in North Delta, Egypt. Data were analyzed using the additive main effects and multiplicative interaction (AMMI) and Tai’s stability parameters. GEIs effects on yield explained 20.3, 20.1, 14.6, and 33.0% of the total variation besides, the first two principal components account for 67.3, 56.3, 64.3, and 83.7% of the explained variance in the four sets, respectively. Six genotypes namely G-4, G-7, G-20, G-34, G-36, and G-39 were found to be most stable and high yielding across environments (GY >2.00 t ha^-1), and located close to zero projection onto the AEC ordinate. Tai’s stability parameters demonstrated that these genotypes were more responsive to the environmental changes. The genotypes G-50 and G-53 showed perfect/static stability (α = -0.95, -0.91, respectively). In contrast, the genotype; G-36 had α = 0 and λ = 1.10, indicating parallel with the environmental effects followed by G-44. Overall, we found that GEIs for grain yield are highly significant in all sets, suggesting that responded differently across environments. This interaction may be a result of changes in genotypes’ relative performance across environments, due to their differential responses to various abiotic factors.     

Iristectorone K,a novel monocyclic triterpene ester from Iris germanica rhizomes growing in Turkey

A new monocyclic triterpene ester (1) was isolated from the rhizomes of Iris germanica from Turkey. Structure elucidation of compound (1) was carried out by the combined application of HMQC, HMBC, DEPT, COSY and NOESY experiments and named as iristectorone K.