New Cyclic Cystine Bridged Peptides from the Sponge Suberites waedoensis

Two new peptides, chujamides A (1) and B (2), were isolated from the marine sponge Suberites waedoensis, which was collected from Korean waters. Based upon the results of the combined spectroscopic analyses, the structures of these compounds were determined to be proline-riched and cyclic cystine bridged dodeca- and undecapeptides. The absolute configurations of all amino acid residues were determined to be l by advanced Marfey’s analysis. The new compounds exhibited weak cytotoxicities against A549 and K562 cell-lines, and compound 2 also demonstrated moderate inhibitory activity against Na⁺/K⁺-ATPase.     

Fluorescence and NIR spectroscopic study on the water interaction in polycarbonate film

Water interactions in polycarbonate films have been studied using fluorescence and NIR Fourier transform spectroscopy. During water sorption process, the fluorescence emission spectra showed sensitive changes with the peak at 332 nm red shifted by 18 nm with water sorption. This red-shifted peak could be due to phenyl-2-phenoxybezoate, which is one of two major thermal degradation products in polycarbonate. In the spectra of phenyl-2-phenoxybenzoate in dimethyl formamide solution, a progressive red shift was also observed with the water addition. By using the NIR spectra, hydrogen-bonding interactions of the sorbed water with polycarbonate were investigated. It was found that water can be analyzed as free water S₀ or single hydrogen bonded water, S₁ while double hydrogen bonded water was negligible. During water immersion, most water species which are present as S₀ species decrease slightly, with a small increase in S₁ species. During desorption, S₀ species decrease sharply, while S1 species is reduced gradually. Two examples of S₁ structure in water-sorbed polycarbonate are proposed.     

Seaweeds and Their Natural Products for Preventing Cardiovascular Associated Dysfunction

Cardiovascular disease (CVD), which involves the onset and exacerbation of various conditions including dyslipidemia, activation of the renin–angiotensin system, vascular endothelial cell damage, and oxidative stress, is a leading cause of high mortality rates and accounts for one-third of deaths worldwide. Accordingly, as dietary changes in daily life are thought to greatly reduce the prevalence of CVD, numerous studies have been conducted to examine the potential use of foods and their bioactive components for preventing and treating CVD. In particular, seaweeds contain unique bioactive metabolites that are not found in terrestrial plants because of the harsh environment in which they survive, leading to in vitro and in vivo studies of their prevention and treatment effects. This review summarizes studies that focused on the beneficial effects of seaweeds and their natural products targeting markers involved in a cascade of mechanisms related to CVD pathogenesis. The purpose of this review is to describe the potential of seaweeds and their natural products for preventing and treating CVD based on in vivo and in vitro studies. This review provides a basis for future research in the field of marine drugs.     

Antihypertensive Effects of IGTGIPGIW Peptide Purified from Hippocampus abdominalis: p-eNOS and p-AKT Stimulation in EA.hy926 Cells and Lowering of Blood Pressure in SHR Model

The aim of this study was to assess the potential hypertensive effects of the IGTGIPGIW peptide purified from Hippocampus abdominalis alcalase hydrolysate (HA) for application in the functional food industry. We investigated the antihypertensive effects of IGTGIPGIW in vitro by assessing nitric oxide production in EA.hy926 endothelial cells, which is a major factor affecting vasorelaxation. The potential vasorelaxation effect was evaluated using 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate, a fluorescent stain. IGTGIPGIW significantly increased the expression of endothelial-derived relaxing factors, including endothelial nitric oxide synthase and protein kinase B, in EA.hy926 cells. Furthermore, oral administration of IGTGIPGIW significantly lowered the systolic blood pressure (183.60 ± 1.34 mmHg) and rapidly recovered the diastolic blood pressure (143.50 ± 5.55 mmHg) in the spontaneously hypertensive rat model in vivo. Our results demonstrate the antihypertensive activity of the IGTGIPGIW peptide purified from H. abdominalis and indicate its suitability for application in the functional food industry.     

Molecular epidemiological investigation of Newcastle disease virus from domestic ducks in Korea

To expand the epidemiological understanding of Newcastle disease virus (NDV) found in domestic ducks in Korea, 14 NDV isolates from apparently healthy domestic ducks were biologically and genetically characterized. Thirteen and 1 isolates of NDV were categorized into lentogenic and velogenic viruses, respectively, based on in vivo pathogenicity tests. Twelve lentogenic viruses showed HA activity to horse RBCs, while 1 lentogenic virus and the velogenic virus were negative. Lentogenic viruses (n=13) had sequence motifs of (112)ERQERL(117) (n=1) or (112)GRQGRL(117) (n=12) at the F0 cleavage site, while the velogenic virus (n=1) had a sequence motif of (112)RRQKRF(117) at the same site. Phylogenetic analysis revealed that at least three distinct genotypes may exist in domestic ducks in Korea; one class I genotype (genotype 2), and two class II (genotypes I and VII) genotypes. The class I virus was most closely related to strains of genotype 2 which were isolated in birds from the USA, Germany and Denmark. Twelve lentogenic class II viruses were grouped together in genotype I, and were then divided into at least three clusters, namely Aomori-like, Ulster2C-like, and V4-like. The velogenic class II virus was assigned to genotype VII which represents viruses responsible for recent epidemics in many Asian countries including Korea. The epidemiological importance of domestic duck isolates of NDV in Korea is discussed.     

Authentication of Rice Using Near‐Infrared Reflectance Spectroscopy

The authentication of rice (Korean domestic rice vs. foreign rice) has been attempted using near‐infrared spectroscopy (NIRS). Two sample sets (n₁ = 280 and n₂ = 200) were used to obtain calibration equations and the spectral regions used for this study were 500–600 nm, 700–900nm, and 980–2,498 nm. Modified partial least square (MPLS) regression was used to develop the prediction model. The standard error of cross validation (SECV) and the r² were 0.165 and 0.91 respectively for 1st calibration set and 0.165 and 0.93 for 2nd calibration set respectively. The results of the independent validation (n₃ = 80) showed that all of 80 samples were identified correctly. Even though authentication of rice was performed successfully using NIRS, the calibration statistics in this study showed that further effort is needed for implementation of NIRS for authentication of rice for industry purposes.     

Induction of resistance against pine wilt disease caused by Bursaphelenchus xylophilus using selected pine endophytic bacteria

Pine wilt disease (PWD) is the most destructive disease threatening pine worldwide. The disease is mainly caused by the pine wood nematode, Bursaphelenchus xylophilus, which is vectored by pine sawyer longhorn-beetles, Monochamus spp. This study aimed to select resistance-inducing pine endophytic bacteria for management of PWD. To set up a defence-related genes expression pattern for screening, four chemical inducers (salicylic acid, γ-aminobutyric acid (GABA), β-aminobutyric acid and α-aminobutyric acid) were tested in vitro on pine calli and in vivo on pine seedlings. Treatment with GABA had the greatest reduction in PWD severity on pine seedlings. The pattern of defence-related gene expression in calli treated with GABA was used to select potential resistance-inducing bacterial strains. In addition, 92 bacterial strains were isolated from pine tree needles and stems and were tested for expression of defence-related genes in pine calli in vitro. Among the tested strains, 13 showed a similar pattern to GABA treatment in at least four tested defence-related genes and were selected for the seedling assay. From the seedling assay, three bacterial strains (16YSM-E48, 16YSM-P180 and 16YSM-P39) showed significant reduction in PWD severity compared to the untreated control. Moreover, among the selected strains, cell-free culture supernatant of strain 16YSM-P180 significantly reduced PWD severity in inoculated pine seedlings. The selected strains were identified based on the 16S rRNA sequence as Pseudomonas putida 16YSM-E48, Curtobacterium pusillum 16YSM-P180 and Stenotrophomonas rhizophila 16YSM-P39. These selected strains are suggested as potential alternatives for management of PWD by induction of systemic resistance.