Genetic characteristics of Korean weedy rice (Oryza sativa L.) by RFLP analysis

Summary The genetic characteristics and classification of 24 strains of Korean weedy rice, two strains of foreign red rice, three Japonica cultivars, one Tongil cultivar and one Indica cultivar (Oryza sativa L.) were investigated at the DNA level using the restriction fragment length polymorphism (RFLP) method. Eighty-three random combinations between six restriction enzymes and forty genomic DNA probes (RG# and KR#) were assayed. Thirty-seven (92.5%) out of the forty probes used showed polymorphisms among the 31 accessions assayed. A high level of polymorphism was found between short and long grain type Korean weedy rices, whereas fewer polymorphisms were presented among strains within each grain type. A dendrogram summarizing genetic similarity coefficients among thirty-one accessions was constructed based on their DNA polymorphisms. The Korean weedy rice strains were classified into two groups identical to the short and long grain types classified by morphological and physiological characters. From the RFLP analysis, it was deduced that the short grain strains of Korean weedy rice belonged to Japonica, while the long grain strains were closer to Indica than to Japonica, and were differentiated into a local ecotype surviving in the growth conditions in the southern part of the Korean peninsula.     

Antioxidative activity of microencapsulated gamma-oryzanol on high cholesterol-fed rats

The effectiveness of microencapsulated gamma-oryzanol (M-gamma-OZ) was evaluated as an antioxidant in Sprague-Dawley rats. Lard containing 100 ppm of gamma-OZ (HCD III) or 100 ppm of M-gamma-OZ (HCD IV) was heated in an oven for 7 days, and the heat-treated lard as an ingredient in a high cholesterol diet (HCD) formulation was tested for analyzing in vivo cholesterol and lipid profiles. The HCDs containing fresh lard (HCD I) and heat-treated lard (HCD II) were fed to the rats for 4 weeks as control groups A and B, respectively, in this experiment. The liver thiobarbituric acid reactive substances values of group C (fed with HCD III) and group D (with HCD IV) were significantly lower (p < 0.05) than that of negative control, group B. One of the cholesterol oxidation products, 7-ketocholesterol, was not detected from group D, indicating that microencapsulation preserved antioxidative activity effectively. The levels of serum total cholesterol and lipoproteins, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein were also affected by heat-induced lipid oxidation.The M-gamma-OZ evidently decreased LDL-cholesterol content and increased HDL-cholesterol in blood samples of tested rats. These results suggested that the M-gamma-OZ was not only effective in inhibiting the hypercholesterolemia of serum and liver but also reduced the oxidation degree of lipids and cholesterol. Therefore, this microencapsulation can be a good potential technique to protect the antioxidant activity of gamma-OZ from heat-induced lipid oxidation.     

Seroprevalence of Canine Herpesvirus‐1 in the Belgian Dog Population in 2000

Canine herpesvirus‐1 (CHV‐1) is known to be associated with fertility and fecundity disorders as well as neonatal mortality in puppies of less than 3 weeks of age. The virus is presumed to be enzootic in dogs all over the world and recent studies in several European countries suggest a high seroprevalence among the dog population. In the year 2000, a total of 647 Belgian canine sera from 102 privately owned patients and 545 breeding dogs were analysed with an enzyme‐linked immunosorbent assay (ELISA). Furthermore 77 of the samples were submitted to two serum neutralization (SN) tests for comparison. An overall CHV‐1 seroprevalence of 45.75% was observed in the Belgian dog population. No significant differences could be observed based on breeding status, reason for consultation or sex. The correlation between the ELISA and both SN tests appeared to be moderate with a significantly greater sensitivity of the ELISA. This study also demonstrated that the CHV‐1 seroprevalence in the Belgian dog population is similar to that in other recently investigated European countries and that the incidence in breeding units is not necessarily higher than in non‐breeding dogs.     

Acaricidal activities of apiol and its derivatives from Petroselinum sativum seeds against Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Tyrophagus putrescentiae

The acaricidal effects of an active constituent derived from Petroselinum sativum seeds and its derivatives were determined using impregnated fabric disk bioassay against Dermatophagoides farinae , Dermatophagoides pteronyssinus , and Tyrophagus putrescentiae and compared with that of synthetic acaricide. The acaricidal constituent of P. sativum was isolated by various chromatographic techniques and identified as apiol. On the basis of LD(50) values against D. farinae and D. pteronyssinus, apiol (0.81 and 0.94 μg/cm(2)) was 12.4 and 10.2 times more toxic than benzyl benzoate (10.0 and 9.58 μg/cm(2)), respectively. In acaricidal studies of apiol derivatives, 3,4-methylenedioxybenzonitrile (0.04, 0.03, and 0.59 μg/cm(2)) was 250, 319, and 20.7 times more toxic than benzyl benzoate (10.0, 9.58, and 12.2 μg/cm(2)) against D. farinae, D. pteronyssinus, and T. putrescentiae. In structure-activity relationships, the acaricidal activities of apiol derivatives could be related to allyl (-C(3)H(5)) and methoxy (-OCH(3)) functional groups. Furthermore, apiol and its derivatives could be useful for natural acaricides against these three mite species.     

Novel tripeptides with α-glucosidase inhibitory activity isolated from silk cocoon hydrolysate

Active compounds with antidiabetic potential were isolated from silk peptide E5K6 by consecutive ultrafiltration and gel filtration using Biogel P-2 and RS-HPLC using a YMC-Pack Pro C18 column. The highest α-glucosidase inhibitory activity of silk peptide E5K6 resulted from fractions with MW <1 kDa. The activities of gel-filtered fractions from silk peptide E5K6 of <1 kDa were assayed in vitro, demonstrating that the fourth peak (F4) had the highest α-glucosidase inhibitory activity (IC(50) = 37.1 mg/mL). F4 of silk peptide E5K6 was separated by HPLC into two peaks. Moreover, the purified compounds were identified as Gly-Glu-Tyr (GEY, MW = 367 Da) and Gly-Tyr-Gly (GYG, MW = 295 Da) according to amino acid sequences, and their α-glucosidase inhibitory activities (IC(50)) were 2.7 and 1.5 mg/mL, respectively.     

Genome sequence of Theileria parva, a bovine pathogen that transforms lymphocytes

We report the genome sequence of Theileria parva, an apicomplexan pathogen causing economic losses to smallholder farmers in Africa. The parasite chromosomes exhibit limited conservation of gene synteny with Plasmodium falciparum, and its plastid-like genome represents the first example where all apicoplast genes are encoded on one DNA strand. We tentatively identify proteins that facilitate parasite segregation during host cell cytokinesis and contribute to persistent infection of transformed host cells. Several biosynthetic pathways are incomplete or absent, suggesting substantial metabolic dependence on the host cell. One protein family that may generate parasite antigenic diversity is not telomere-associated.     

A method of capability evaluation for upland soils

As one of the important capability determinants of upland soils, fertility was taken up as the object of evaluation in this study.

On the basis of correlation analysis, factor analysis (FA) was applied to a set of 12 variates (humus, total nitrogen, available nitrogen, clay. sand, total phosphorus, Bray-P. HC1-P, CEC, percentage base saturation. exchangeable calcium, and pH).

Four mutually independent and clearly definable fertility component factors were consistently extracted from the 12 variates for the entire set of 94 surface soil samples and for different strata of the samples. The fertility status of each sample soil could be objectively designated by the scores of the four factors.

As a means of summarizing the information obtained, taxonomic distances between all pairs of the samples were computed from these 4 factor scores and subjected to numerical taxonomy. Six fertility groups were formulated, each of which was characterized by one or more of the fertility components. This fertility classification based on the present state of soil properties could be of use in pointing to the proper direction of fertility amelioration and improvement for each group of Boils.     

Real-time identification of the draft system using neural network

Making a good model is one of the most important aspects in the field of a control system. If one makes a good model, one is now ready to make a good controller for the system. The focus of this thesis lies on system modeling, the draft system in specific. In modeling for a draft system, one of the most common methods is the “least-square method”; however, this method can only be applied to linear systems. For this reason, the draft system, which is non-linear and a time-varying system, needs a new method. This thesis proposes a new method (the MLS method) and demonstrates a possible way of modeling even though a system has input noise and system noise. This thesis proved the adaptability and convergence of the MLS method.