Anti-hypercholesterolemic and anti-atherosclerotic effects of polarized-light therapy in rabbits fed a high-cholesterol diet

The effects of polarized-light therapy (PLT) on high-cholesterol diet (HCD)-induced hypercholesterolemia and atherosclerosis were investigated in comparison with that of lovastatin in rabbits. Hypercholesterolemia was induced by feeding male New Zealand white rabbits with 1% cholesterol in diet for 2 weeks and maintained with 0.5% cholesterol for 6 weeks, followed by normal diet for 2 weeks for recovery. Lovastatin (0.002% in diet) or daily 5-min or 20-min PLT on the outside surface of ears was started 2 weeks after induction of hypercholesterolemia. Hypercholesterolemic rabbits exhibited great increases in serum cholesterol and low-density lipoproteins (LDL) levels, and finally severe atheromatous plaques formation covering 57.5% of the arterial walls. Lovastatin markedly reduced both the cholesterol and LDL, but the reducing effect (47.5%) on atheroma formation was relatively low. By comparison, 5-min PLT preferentially decreased LDL, rather than cholesterol, and thereby potentially reduced the atheroma area to 42.2%. Notably, 20-min PLT was superior to lovastatin in reducing both the cholesterol and LDL levels as well as the atheromatous plaque formation (26.4%). In contrast to the increases in blood alanine transaminase and aspartate transaminase following lovastatin treatment, PLT did not cause hepatotoxicity. In addition, PLT decreased platelets and hematocrit level. The results indicate that PLT attenuates atherosclerosis not only by lowering blood cholesterol and LDL levels, but also by improving blood flow without adverse effects. Therefore, it is suggested that PLT could be a safe alternative therapy for the improvement of hypercholesterolemia and atherosclerosis.     

Monitoring of antibiotic resistance in bacteria isolated from laboratory animals

The drug resistance of microorganisms isolated from laboratory animals never treated with antibiotics is being reported consistently, while the number of laboratory animals used in medicine, pharmacy, veterinary medicine, agriculture, nutrition, and environmental and health science has increased rapidly in Korea. Therefore, this study examined the development of antimicrobial resistance in bacteria isolated from laboratory animals bred in Korea. A total of 443 isolates (7 species) containing 5 Sphingomonas paucimobilis, 206 Escherichia coli, 60 Staphylococcus aureus, 15 Staphylococcus epidermidis, 77 Enterococcus faecalis, 27 Citrobacter freundii, 35 Acinetobacter baumannii were collected from the nose, intestine, bronchus and reproductive organs of ICR mice and SD rats. Of these species, Acinetobacter baumannii and Enterococcus faecalis showed significant antimicrobial resistance according to the minimum inhibition concentration (MIC) in E-test. In case of Acinetobacter baumannii, several isolates showed MIC values 16-128 μg/mL for cefazolin and cefoxitin, and higher resistance (128-512 μg/mL) to nitrofurantoin than that of standard type. Resistance to cefazolin, cefoxitin and nitrofurantoin was detected in 17.14, 20.00, and 8.57% of the Acinetobacter baumannii isolates, respectively. In addition, 44.1% of the Enterococcus faecalis isolates collected from the laboratory animals were resistant to oxacillin concentration of 16-32 μg/mL range, while MIC value of standard type was below oxacillin concentration of 6 μg/mL. These results suggest that in rodent species of laboratory animals, Acinetobacter baumannii are resistance to cefazolin, cefoxitin and nitrofurantoin, whereas those of Enterococcus faecalis were resistance to oxacillin.     

Genome wide QTL mapping to identify candidate genes for carcass traits in Hanwoo (Korean Cattle)

Meat quality traits are the most economically important traits affecting the beef industry in Korea. We performed a whole genome quantitative trait locus (QTL) mapping study of carcass data in Hanwoo Korean cattle. Two hundred sixty-six Hanwoo steers from 65 sires were genotyped using a 10K Affymetrix SNP chip. The average SNP interval across the bovine genome was 1.5Mb. Associations between each individual SNP and four carcass traits [carcass weight (CWT), eye muscle area (EMA), back fat thickness (BFT), and marbling (MAR)] were assessed using a linear mixed model of each trait. Combined linkage and linkage disequilibrium analysis (LDLA) detected six potential QTL on BTA04, 06, 13, 16, 17, and 23 at the chromosome-wise level (P<0.05). Two MAR QTL were detected at 52.2 cM of BTA06 and 46.04 cM of BTA17. We identified three genes (ARAP2, LOC539460, and LOC511424) in the QTL region of BTA06 and seven genes (RPS14, SCARB1, LOC782103, BRI3BP, AACS, DHX37, and UBC) in the QTL region of BTA17. One significant QTL for CWT was detected at 100 cM on BTA04 and the corresponding QTL region spanned 1.7 cM from 99.7 to 101.4 cM. For EMA QTL, one significant QTL was detected at 3.9 cM of BTA23 and the most likely QTL interval was 1.4 cM, placing 15 candidate genes in the marker bracket. Finally, two QTL for BFT were identified at 68 cM on BTA13 and 24 cM on BTA16. The LPIN3 gene, which is functionally associated with lipodystrophy in humans, is located in the BFT QTL on BTA13. Thus, two potential candidate genes, acetoacetyl-CoA synthetase (AACS) and lipin (LPIN), were detected in QTL regions on BTA17 for MAR and BTA13 for BFT, respectively. In conclusion, LDLA analysis can be used to detect chromosome regions harboring QTL and candidate genes with a low density SNP panel, yielding relatively narrow confidence intervals regarding location.     

The relationship between conidial dose,moulting and insect developmental stage on the susceptibility of cotton aphid,Aphis gossypii,to conidia of Lecanicillium attenuatum,an entomopathogenic fungus

The cotton aphid is one of the most serious pests of greenhouse vegetable crops worldwide. It is difficult to control because field populations usually include simultaneously several insect developmental stages. The current research evaluated an isolate (CS625) of Lecanicillium attenuatum, a fungal pathogen of aphids, as to its virulence against different developmental stages of cotton aphid, Aphis gossypii. The influence on mortality of several other factors also was examined: (a) insect moulting, (b) the number of conidia attached to insect cuticles and (c) germination rates of conidia on cuticles of aphids at various developmental stages. Mortality of cotton aphids treated with L. attenuatum conidia varied according to the developmental stage of the host, i.e. the LT_50s with third-instar nymphs and adults was shorter than with first-instar nymphs. The number of spores attached to the surface of first-instar nymphs was approximately one-half of that on third-instar nymphs and adults. Also, the level of spore germination on the surface of first-instar nymphs was lower than on the surface of other stages of the aphid. After moulting, the numbers of conidia attached to new insect cuticles were less than on exuviae. These results suggest that early nymphal stages of cotton aphids may escape fungal disease due, at least in part, to a combination of three factors: low numbers of conidia attached to their cuticles; low levels of conidial germination and rapid ecdyses, which removed conidia before their germ tubes penetrated the host hemolymph.     

Comparative evaluation of three Lactobacilli with strain-specific activities for rats when supplied in drinking water

To test the in vivo benefits of three lactobacilli and to compare their different efficacies based on strain-specific activities by using rats as an experimental model, a growth-promotion and a challenge trial were conducted. The three strains, Lactobacillus salivarius G1-1, Lactobacillus reuteri G22-2, and Lactobacillus reuteri G8-5 shared antimicrobial, bile-salt-hydrolase and amylolytic activities in vitro, respectively. In the 17 day growth-promotion trial, 48 rats were allotted to four treatments with 12 replicates per treatment: a control group, which received saline, as well as three experimental groups, which received 10⁸ cells/ml of one of the three lactobacilli in saline suspension. The results showed that compared with the control group, L. reuteri G8-5 significantly improved feed efficiency and decreased fecal pH values on days 8 and 17, concomitant with reduced faecal coliform counts on d 17 (p < 0.05). All treatments with lactobacilli caused an increase in the moisture content of the faeces and a decrease in the serum total cholesterol and blood urea nitrogen levels. High-density lipoprotein cholesterol was only elevated for rats which received L. reuteri G22-2. In the Salmonella-challenge trial, 40 rats were allotted to five treatments (8 replicates per treatment) which consisted of a positive control (infected, no Lactobacillus pretreatment), a negative control (uninfected, no Lactobacillus pretreatment) and three Lactobacillus-pretreated groups (10⁹ cells/ml in saline). The results showed that rats in all Lactobacillus pretreated groups were protected from infection with significantly higher weight gain, feed intake and feed efficiency compared with positive control rats (p < 0.05). Rats treated with L. salivarius G1-1 and L. reuteri G22-2 tended to exhibit higher weight gains than those pretreated with L. reuteri G8-5. Significantly lower Salmonella shedding in faeces, Salmonella numbers in the spleen and the relative weight of the spleen were observed in the Lactobacillus groups (p < 0.05). Based on the overall results, it can be concluded that not all strains within the same lactobacilli species show similar effects and that some of the beneficial functionalities to animals were strain-specific. Therefore strains for practical application need to be carefully selected based on their strain-specific characters.     

Validation of trans-acting elements that promote exon 7 skipping of SMN2 in SMN2-GFP stable cell line

Spinal muscular atrophy is a genetic disease in which the SMN1 gene is deleted. The SMN2 gene exists in all of the patients. Alternative splicing of these two genes are different. More than 90% of exon 7 included form is produced from SMN1 pre-mRNA, whereas only ～20% of exon 7 included form is produced from SMN2 pre-mRNA. Only exon 7 inclusion form produces functional protein. Exon 7 skipped SMN isoform is unstable. Here we constructed a GFP reporter system that recapitulates the alternative splicing of SMN1 and SMN2 pre-mRNA. We designed a system in which GFP protein is expressed only when exon 7 of is included in alternative splicing. The stable cell that expresses SMN1-GFP produces ～4 times more GFP protein than the stable cell line that expresses SMN2-GFP; as demonstrated by microscopy, FACS analysis and immunoblotting. In addition the ratio of exon 7 inclusion and skipping of SMN1-GFP and SMN2-GFP pre-mRNA was similar to endogenous SMN1 and SMN2 pre-mRNA as shown in RT-PCR. Furthermore the knockdown with hnRNP A1 shRNA, a known protein which promotes exon 7 skipping of SMN2, induces exon 7 inclusion of exon 7 in SMN2-GFP pre-mRNA in SMN2-GFP cell line. We conclude that we have established the stable cell lines that recapitulate alternative splicing of the SMN1 and SMN2 genes. The stable cell line can be used to identify the trans-acting elements with siRNA.     

Attractiveness of conspecific stink bugs to adult stink bug-baited traps in soybean fields

The attractiveness of live adult stink bugs used as baits in traps in soybean fields, Milyang, Korea, to conspecific stink bugs was evaluated. Both sexes of bean bug, Riptortus pedestris Fabricius (Hemiptera: Alididae), and one-banded stink bug, Piezodorus hybneri Gmelin (Hemiptera: Pentatomidae), were attracted to conspecific male adults-baited traps. Likewise, both sexes of brown-marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), and sole bug, Dolycoris baccarum L. (Hemiptera: Pentatomidae), were attracted to traps baited with conspecific male stink bugs. However, in Nezara antennata Scott (Hemiptera: Pentatomidae), both male and female used as baits in traps were attractive to conspecific adults. Accordingly, these results suggest that the only male adults of H. halys and D. baccarum and both sexes of N. antennata are attractive to conspecific male stink bugs.     

A quantile‐slicing approach for sufficient dimension reduction with censored responses

Sufficient dimension reduction (SDR) that effectively reduces the predictor dimension in regression has been popular in high‐dimensional data analysis. Under the presence of censoring, however, most existing SDR methods suffer. In this article, we propose a new algorithm to perform SDR with censored responses based on the quantile‐slicing scheme recently proposed by Kim et al. First, we estimate the conditional quantile function of the true survival time via the censored kernel quantile regression (Shin et al.) and then slice the data based on the estimated censored regression quantiles instead of the responses. Both simulated and real data analysis demonstrate promising performance of the proposed method.     

Estimation of paracellular conductance of primary rat alveolar epithelial cell monolayers.

Freshly isolated rat type II pneumocytes, when grown on permeable tissue culture-treated polycarbonate filters, form confluent alveolar epithelial cell monolayers (RAECM). Cells in RAECM undergo transdifferentiation, exhibiting over time morphological and phenotypic characteristics of type I pneumocytes in vivo. We recently reported that transforming growth factor-beta(1) (TGF-beta(1)) decreases overall monolayer resistance (R(te)) and stimulates short-circuit current in a dose-dependent manner. In this study, we investigated the effects of TGF-beta(1) (50 pM) or 10% newborn bovine serum (NBS) on modulation of paracellular passive ion conductance and its contribution to total passive ion conductance across RAECM. On days 5-7 in culture, tight-junctional resistance (R(tj), kOmegacm(2)) of RAECM, cultured in minimally defined serum-free medium (MDSF) with or without TGF-beta(1) or NBS, was estimated from the relationship between observed transmonolayer voltage and resistance after addition of gramicidin D to apical potassium isethionate Ringer solution under open-circuit conditions. NaCl Ringer solution bathed the basolateral side throughout the experimental period. Results showed that transmonolayer conductance (1/R(te)) and tight-junctional conductance (1/R(tj)) are 0.59 and 0.14 mS/cm(2) for control monolayers in MDSF, 1.59 and 0.38 mS/cm(2) for monolayers exposed to TGF-beta(1), and 0.38 and 0.18 mS/cm(2) for monolayers grown in the presence of NBS. The contributions to total transepithelial ion conductance by the paracellular pathway are estimated to be 23, 23, and 47% for control, TGF-beta(1)-exposed, and newborn bovine serum (NBS)-treated RAECM, respectively.