Larval and pupal toxicity effects of Plectranthus amboinicus, Bacillus sphaericus and predatory copepods for the control of the dengue vector, Aedes aegypti

The efficacy of copepod Mesocyclops aspericornis (Daday) combined with the larvicide Bacillus sphaericus (Bs) and a plant extract of Plectranthus amboinicus leaf abstract (PALE), used jointly and singly, was studied against Aedes aegypti in the laboratory. P. amboinicus leaf extract of 20, 40, 60, 80 and 100 ppm caused significant mortality against Ae. aegypti larvae. The LC₅₀ and LC₉₀ values for I to IV instars larvae and pupae were 26.12, 35.36, 45.76, 52.32 and 63.82 ppm, respectively. The LC₉₀ values for I to IV instars larvae and pupae were 82.53, 92.65, 108.06, 119.47 and 131.71 ppm, respectively. Under laboratory conditions, copepods treatment produced 7.9% predatory efficiency against 1st instar larvae of Ae. aegypti, at a copepod:larvae ratio of 1:10. When copepod treatment was combined with PALE this was increased to 8.7. The treatment of copepods combined with Bs and PALE yielded a better and more sustainable result (9.6%) than the agents used individually. This predation efficiency may be caused by detrimental effects of the P. amboinicus active principle compound (carvacrol) on the mosquito larvae. Our results suggest that the combined application of microbial insecticide (Bs), copepods and P. amboinicus leaf extract may be used to control Aedes populations.     

Structural transformation of oyster,hard clam,and sea urchin shells after calcination and their antibacterial activity against foodborne microorganisms

Fisheries Science - The aim of this study was to evaluate the antibacterial properties of oyster, hard clam, and sea urchin shell powders as a result of calcination. After subjection to calcination...     

Distribution and migration of Japanese common squid, Todarodes pacificus, in the southwestern part of the East (Japan) Sea

Data on squid catches of Korean and Japan, water temperatures at depth of 100 m, and night-visible images of fishing boats collected in the East (Japan) Sea from 1970 to 1999 were analyzed to examine the distribution and migration of the Japanese common squid, Todarodes pacificus, in the southwestern part of the East (Japan) Sea. The main fishing grounds detected from squid catch in each grid (0.5° latitude × 0.5° longitude) by Korean squid fishery and night-visible images provided by the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) were situated in the southwestern part of the East (Japan) Sea. The distribution and migration route was illustrated from squid catch in each grid and DMSP OLS image. In years of high catches, the fishing grounds were situated mainly between Ulleung Island and the eastern coastal waters of Korea, while in years of low catches they were situated between Ulleung Island and the Yamato Bank in the central East (Japan) Sea. The center of fishing activity began moving northward from around the Korea/Tsushima strait to the northern boundary of the Tsushima Warm Current in March, reaching into the Yamato Bank in September, and then returning to the strait by February. The northward and southward migration routes differed; the northward migration route occurred closer to the mainland coast of Korea than the southward migration route did. This work suggests T. pacificus begin their northward migration almost 2 months earlier than previously suggested.     

DEMAND FOR AQUACULTURE PRODUCTS IN TAIWAN: AN APPLICATION OF THE GENERALIZED MODEL

ABSTRACT

Policy decisions on what aquaculture products to develop require information on consumer demand for cultured species. However, information on the structure of demand for aquaculture products is limited and what few studies there are in Taiwan, where aquaculture is a major industry, suffer from methodological problems. To clear up some of these problems, we used modified nonnested testing techniques and performance forecasting to determine which generalized models could best estimate the demand for Taiwanese aquaculture products. The results of modified nonnested testing of the aquaculture demand system showed that prices predetermined and quantities predetermined could be used to estimate demand. The generalized ordinary demand model was able to better forecast performance than the generalized inverse demand model. We used the likelihood ratio test to discriminate among the four competing models for the generalized ordinary model; the AIDS model could be more suitably applied to the data. A more general model that is able to incorporate different dynamic structures (partial adjustment, first autoregressive, and static). This general framework is applied to the AIDS model. The first autoregressive AIDS model we used to calculate the own and cross-price elasticities for milkfish, tilapia, shrimp, shellfish, and carps found that price elasticities varied across fish type, that some products had high long-run own price elasticities, and that the demand for aquaculture products was largely determined by inertia.     

Fibrillar microfilaments associated with a high-amylose rice, goami 2, a mutant of ilpumbyeo, a high-quality japonica rice

The ultrastructure of cooked and malt-treated cooked rice of Ilpumbyeo (IP) and its mutant Goami 2 (G2), which have extreme contrasts in physicochemical properties, cooking quality, and ultrastructural characteristics in raw grains (1, 2), was compared. In cooked rice of IP, starch granules in endosperm cells were evenly coalesced, appearing as homogeneously smooth sheetlike matrix and/or globules, whereas those in G2 were a heterogeneously coarse matrix in which a novel structural feature, the microfilaments, was embedded. In malt-treated cooked rice of IP, most starch was hydrolyzed by the malt enzymes, appearing as empty vacuoles surrounded by the cell wall, whereas that in G2 was highly resistant to malt treatment, remaining as distinct structural features, the malt-resistant compound starch granules. The property of G2's compound starch granules, which are tolerant of mechanical and chemical treatments thereby retaining their structural integrity (2) and of cooking and malt treatment thereby retaining their physical hardness, appears to play a major role in determining the quality of cooked rice of G2.     

Metabolic dependence of green tea on plucking positions revisited: a metabolomic study

The dependence of global green tea metabolome on plucking positions was investigated through (1)H nuclear magnetic resonance (NMR) analysis coupled with multivariate statistical data set. Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection on latent structure-discriminant analysis (OPLS-DA), were employed for a finding metabolic discrimination among fresh green tea leaves plucked at different positions from young to old leaves. In addition to clear metabolic discrimination among green tea leaves, elevations in theanine, caffeine, and gallic acid levels but reductions in catechins, such as epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epigallocatechin-3-gallate (EGCG), glucose, and sucrose levels were observed, as the green tea plant grows up. On the other hand, the younger the green tea leaf is, the more theanine, caffeine, and gallic acid but the lesser catechins accumlated in the green tea leaf, revealing a reverse assocation between theanine and catechins levels due to incorporaton of theanine into catechins with growing up green tea plant. Moreover, as compared to the tea leaf, the observation of marked high levels of theanine and low levels of catechins in green tea stems exhibited a distinct tea plant metabolism between the tea leaf and the stem. This metabolomic approach highlights taking insight to global metabolic dependence of green tea leaf on plucking position, thereby providing distinct information on green tea production with specific tea quality.     

In vitro isolation and characterization of bovine Neospora caninum in Korea

The brains of nine aborted bovine fetuses and two newborn calves born from dams suspected to be infected with Neospora caninum were homogenized and inoculated into Vero cells. All fetuses and calves were from cows determined as seropositive to N. caninum by an IFA test. Sera and thoracic fluids of all fetuses and calves also revealed high antibody titer to N. caninum by IFAT ranging from 1:800 to 1:3200. N. caninum was isolated from the brains of one aborted fetus and one newborn calf when the brain homogenates were grown continuously in Vero cell culture. N. caninum tachyzoites, giemsa-positive, were first observed on Days 45 and 56 postinoculation in the newborn calf and the aborted fetus, respectively. The isolates (KBA-1 and KBA-2) were morphologically and ultrastructurally similar to previously published Neospora isolates. The isolated parasites were confirmed as N. caninum by means of the antigenic reactivities, immunostaining, PCR and southern blotting, and electron microscopy.     

Direct evidence of surface infestation of seeds and tubers by Plasmodiophora brassicae and quantification of spore loads

Using quantitative PCR, DNA of Plasmodiophora brassicae, the causal agent of clubroot, was detected and quantified on canola, pea and wheat seeds, as well as on potato tubers, all harvested from clubroot‐infested fields in Alberta, Canada. Quantifiable levels of infestation were found on seven of the 46 samples analysed, and ranged from <1·0 × 10³ to 3·4 × 10⁴ resting spores per 10 g seeds; the vast majority (80–100%) of resting spores on these samples were viable, as determined by Evan’s blue vital staining. However, the levels of infestation found were generally lower than that required to cause consistent clubroot symptoms in greenhouse plant bioassays. While the occurrence of P. brassicae resting spores on seeds and tubers harvested from clubroot‐infested fields suggests that seedborne dissemination of this pathogen is possible, practices such as commercial seed cleaning may be sufficient to effectively mitigate this risk.