Brucella abortus infection in indigenous Korean dogs

Three dogs reared on a dairy farm with a high incidence for Brucella abortus were serologically positive for B. abortus and no other Brucella spp. The identity of the organism was confirmed to be B. abortus by AMOS (abortus melitensis ovis suis)-polymerase chain reaction with specific primers for B. canis. One hundred percent homology of the canine isolate and the bovine pathogen isolated from the farm was demonstrated. The only possible source of infection was infected cattle on the same farm. It is suggested that dogs be routinely included in brucellosis surveillance and eradication programs.     

The effects of CO2 gas stunning on meat quality of cattle compared with captive bolt stunning

The aim of this study is to assess the effect of CO₂ gas stunning which has not been conducted until now in comparison with captive bolt stunning on the meat quality of cattle. A total of 40 steers were slaughtered following two stunning processes: CO₂ gas stunning (n=20), exposure at 70% CO₂ gas atmosphere for 140 sec; and captive bolt stunning (CBS, n=20). The slaughtered steers were classified into Group A (620–710 kg) and Group B (720–790 kg) by their live weight. CO₂ gas stunning decreases pH value (p<0.05) but increases lightness (p<0.001) and sarcomere length (p<0.001 and p<0.01 for Group A and Group B, respectively) in all live weight groups. Drip loss was increased with CO₂ gas stunning in Group A (620–710 kg of live weight) (p<0.05), whereas WBSF was decreased with CO₂ gas stunning in Group B (720–790 kg of live weight) (p<0.001). Therefore, CO₂ gas stunning negatively affects muscle pH and water-holding capacity in steers but CO₂ gas stunning can improve the tenderness and lightness compared with captive bolt stunning in cattle.     

Analysis of differentially expressed genes in soybean leaf tissue of tolerant and susceptible cultivars under flooding stress revealed by RNA sequencing

Journal of Crop Science and Biotechnology - Flooding stress causes severe yield reduction in soybean worldwide. The development of stress-tolerant cultivars could be an effective measure to reduce...     

Evaluation of soybean cultivars for resistance to phomopsis seed decay in Korea

Phomopsis seed decay (PSD), primarily caused by Phomopsis longicolla, is one of the most important seed-borne diseases and causes serious seed yield loss in soybean. This study was performed to evaluate reactions to P. longicolla in Korean soybean major elite cultivars, which were mainly used for parents of genetic mapping populations. The natural incidence of P. longicolla and other seed-borne fungi was determined in the fields at three different locations in South Korea during 2009–2010. The significant differences in sensitivity to seed-borne diseases were shown among cultivars. Taekwangkong exhibited the greatest resistance to P. longicolla with average incidence of 0.33% and other seed-borne fungi with average incidence of 6.17%. Moreover, Taekwangkong was free of P. longicolla infection both in Milyang and in Daegu. To confirm the effective resistance source, the Korean virulent strain of P. longicolla, SSLP-3, was inoculated artificially on soybean of R4–R7 growth stage in the greenhouse. Taekwangkong exhibited a higher level of resistance to P. longicolla with significantly lower incidence (8.67%) than any other Korean elite cultivars (78.0–99.33%) and the previously reported resistant PI genotypes (35.0–55.67%). Further verification of resistance in Taekwangkong to P. longicolla by testing germination vigor of healthy seeds in vitro showed a higher germination rate than those of the susceptible cultivars. It could be suggested that Taekwangkong is a newly identified resistance source and the better source of resistance to P. longicolla to develop breeding populations for exploiting resistance gene(s) in further studies.     

Topical application of epidermal growth factor accelerates wound healing by myofibroblast proliferation and collagen synthesis in rat

Recombinant human epidermal growth factor (rhEGF) stimulates the proliferation and migration of epithelial cells in human cell culture systems and animal models of partial-thickness skin wounds. This study investigated the effect of a topical rhEGF ointment on the rate of wound healing and skin re-epithelialization in a rat full thickness wound model, and verified whether or not the rhEGF treatment affected both myofibroblast proliferation and collagen synthesis in the dermis. When rhEGF (10 µg/g ointment) was applied topically twice a day for 14 days, there was significantly enhanced wound closure from the 5th to the 12th day compared with the control (ointment base treatment) group. A histological examination at the postoperative 7th day revealed that the rhEGF treatment increased the number of proliferating nuclear antigen immunoreactive cells in the epidermis layer. In addition, the immunoreactive area of alpha-smooth muscle actin and the expression of prolyl 4-hydroxylase were significantly higher than those of the control group. Overall, a topical treatment of rhEGF ointment promotes wound healing by increasing the rate of epidermal proliferation and accelerating the level of wound contraction related to myofibroblast proliferation and collagen deposition.     

Effect of processing conditions on warpage of film insert molded parts

In order to investigate effects of injection molding conditions on viscoelastic behavior and thermal deformation of film insert molded (FIM) parts, injection molding was performed with various conditions such as injection speed, melt temperature, and packing time. It was shown that variation of the warpage was decreased monotonically with increasing injection speed and exhibited a bell-shaped curve as a function of melt temperature. Warpage variation was not affected by the packing time significantly and the proportional relationship between warpage of the film insert molded part and shrinkage of the injection molded part without film was observed. The FIM specimens produced with unannealed films showed the warpage reversal phenomenon (WRP) during annealing and the magnitude of reversed warpage was affected significantly by the injection parameters and the extent of thermal shrinkage of the unannealed film. Warpage of the FIM specimen was predicted by three dimensional numerical flow and stress analyses and the predicted values showed a good agreement with the experimental results.     

Identification of a cluster of oligonucleotide repeat sequences and its practical implication in melon (<Emphasis Type="Italic">Cucumis melo</Emphasis> L.) breeding

A cluster of oligonucleotide repeat sequences was identified that is linked to the melon (Cucumis melo L.) andromonoecious (a) locus, which controls andromonoecy. Six different repeat units, ranging from 11 to 49 base pairs, were clustered within a 0.6-kb intergenic region. The number of repeat units varied from two to six. After sequence analysis of diverse melon germplasms, four haplotypes of this cluster were identified. Length variations among the four haplotypes resulted from insertion or deletion of repeat sequences. Particularly, a tandem array of six repeats of 21 nucleotides was a hotspot for insertion/deletion mutations. A simple PCR-based marker was developed to identify haplotypes of this cluster based on the length polymorphism. In practice, this marker was successfully used in genetic purity tests of melon F₁ hybrid cultivars. Four self-pollinated contaminants, which were confirmed by phenotypic examination in grow-out tests, were easily discriminated from 99 F₁ hybrid individuals. In addition, the genetic distance between this marker and the andromonoecious (a) locus was calculated as 7.9 cM, after analyzing melon F₂ populations originating from a cross between monoecious and andromonoecious parental lines. Therefore, this marker will be useful as a recombinant selection marker in marker-assisted backcrossing of monoecy in melon breeding programs.     

Estimation of genetic distance and its predictability of F<Subscript>1</Subscript> hybrid performance in barley

Heterotic performance of hybrids is dependent upon the amount of genetic variability among parents and combining ability of alleles at the loci associated with target traits. This study was carried out to determine if (1) pedigree-based genetic distance could explain molecular levels of genetic diversity, and (2) molecular marker-based genetic distance could predict the degree of hybrid performance in barley. The average value of Random Amplified Polymorphic DNA (RAPD)-based genetic similarity for all 58 genotypes was 0.641. Twenty-two hulless barley and eight malt barley varieties showed low levels of genetic diversity with higher similarity values than the average of all or of the hulled barley variety pool. Coefficients of parentage (COPs) computed for 1,653 pairs of 58 Korean barley varieties ranged from 0 to 0.984 with a mean of 0.048. Correlation between the genealogical and RAPD-based genetic similarity matrices was 0.256 (P < 0.01). Correlation values for the related and for all (related + unrelated) genotype pairs were almost similar to each other, indicating that the unrelated genotypes share a large portion of genomes alike in state, not identical by descent. RAPD-based genetic similarity estimates among parents were poorly correlated with their hybrid performance such as 1,000-grain weight (r = 0.34), biomass yield (r = −0.12), and grain yield (r = −0.04) for 11 genotype pairs of hulled barley. However, correlations between heterozygosity at marker loci and hybrid performance for biomass and grain yield slightly increased when two F1 hybrids were excluded in the analysis due to their low yield.     

Effects of exposure to genistein and estradiol on reproductive development in immature male mice weaned from dams adapted to a soy-based commercial diet

Genistein, a soybean-originated isoflavone, is widely consumed by humans for putative beneficial health effects but its estrogenic activity may adversely affect the development of male reproductive system. Twenty one-day-old ICR mice weaned from dams fed with a soybean-based diet throughout gestation and lactation were exposed by gavage to genistein (2.5 mg/kg b.w./day) or 17beta-estradiol (7.5 microg/kg b.w./day) for five weeks. Corn oil was used as a negative control. The animals were fed with a casein-based AIN-76A diet throughout the experimental periods. There were no significant differences in body and organ weights of mice among experimental groups. No significant differences in sperm counts and sperm motile characteristics were found between control and genistein groups. Treatment of 17beta-estradiol caused a significant decrease in prostate weight and epididymal sperm counts compared to the control (p<0.05). The levels of phospholipid hydroxide glutathione peroxidase in the testis and prostate of mice exposed to genistein or 17beta-estradiol were significantly higher than that of the control mice (p<0.05). 17beta-estradiol treatment caused degeneration and apoptosis of germ cells in the testis, depletion and degeneration in the epididymal epithelium, and hyperplasia of mucosal fold region in the prostate of mice. Genistein treatment did not cause any lesion in the testis, epididymis, and prostate. These results suggest that dietary uptake of genistein during juvenile period may not affect male reproductive development and functions.