Biomass accumulations and the distribution of nitrogen and phosphorus within three<Emphasis Type="Italic">Quercus acutissima</Emphasis> stands in central Korea

Above- and belowground biomass and nitrogen (N) and phosphorus (P) distribution within threeQuercus acutissima stands were investigated in central Korea. The average age (year) and diameter at breast height (DBH, cm) were 10.8 and 7.9 for Stand 1, 38.2 and 17.1 for Stand 2, and 44.0 and 20.7 for Stand 3, respectively. Fifteen trees were destructively harvested for dimension analysis of component biomass (stem wood, stem bark, foliage, branches, and roots) plus N and P concentrations. Total biomass (t ha^-1) was 88.7 for Stand 1, 154.9 for Stand 2, and 278.1 for Stand 3 while N and P contents in all tree components (kg ha^-1) were 483.3 and 52.2, 697.1 and 55.0, and 1113.9 and 83.7. Nitrogen concentrations were highest in the foliage, followed by the stem bark, branches or roots, and stem wood. In contrast, P concentrations were greatest in the roots, then foliage, branches, stem bark, and stem wood. In general, N and P concentrations in these components significantly decreased with tree age and DBH, while N and P contents significantly increased with age and size. These relationships were stronger for size than for age. Our current data could be utilized to estimate N and P budgets for silvicultural practices, including fertilization, thinning, and harvesting.     

<Emphasis Type="Italic">Lactobacillus curvatus</Emphasis> WiKim38 isolated from kimchi induces IL-10 production in dendritic cells and alleviates DSS-induced colitis in mice

Probiotics such as lactobacilli and bifidobacteria have healthpromoting effects by immune modulation. In the present study, we examined the immunomodulatory properties of Lactobacillus curvatus WiKim38, which was newly isolated from baechu (Chinese cabbage) kimchi. The ability of L. curvatus WiKim38 to induce cytokine production in bone marrow-derived dendritic cells (BMDCs) was determined by enzyme-linked immunosorbent assay. To evaluate the molecular mechanisms underlying L. curvatus Wikim38-mediated IL-10 production, Western blot analyses and inhibitor assays were performed. Moreover, the in vivo anti-inflammatory effects of L. curvatus WiKim38 were examined in a dextran sodium sulfate (DSS)-induced colitis mouse model. L. curvatus WiKim38 induced significantly higher levels of IL-10 in BMDCs compared with that induced by LPS. NF-κB and ERK were activated by L. curvatus WiKim38, and an inhibitor assay revealed that these pathways were required for L. curvatus WiKim38-induced production of IL-10 in BMDCs. An in vivo experiment showed that oral administration of L. curvatus WiKim38 increased the survival rate of mice with DSS-induced colitis and improved clinical signs and histopathological severity in colon tissues. Taken together, these results indicate that L. curvatus Wikim38 may have health-promoting effects via immune modulation, and may thus be applicable for therapy of various inflammatory diseases.     

Enhanced cellular delivery and transfection efficiency of plasmid DNA using positively charged biocompatible colloidal gold nanoparticles

Efficient and safe nonviral gene delivery systems are a prerequisite for the clinical application of therapeutic genes. In this study, we report an enhancement of the transfection efficiency of plasmid DNA, via the use of positively charged colloidal gold nanoparticles (PGN). Plasmid DNA encoding for murine interleukin-2 (pVAXmIL-2) was complexed with PGN at a variety of ratios. The delivery of pVAXmIL-2 into C2C12 cells was dependent on the complexation ratios between PGN and the plasmid DNA, presented the highest delivery at a ratio of 2400:1. After complexation with DNA, PGN showed significantly higher cellular delivery and transfection efficiency than did the polyethylenimines (PEI) of different molecular weights, such as PEI25K (m.w. 25 kd) and PEI2K (m.w. 2 kd). PGN resulted in a cellular delivery of pVAXmIL-2 6.3-fold higher than was seen with PEI25K. The PGN/DNA complex resulted in 3.2- and 2.1-fold higher murine IL-2 protein expression than was seen in association with the PEI25K/DNA and PEI2K/DNA complexes, respectively. Following intramuscular administration, PGN/DNA complexes showed more than 4 orders of magnitude higher expression levels as compared to naked DNA. Moreover, the PGN/DNA complexes showed higher cell viability than other cationic nonviral vectors. Collectively, the results of this study suggest that the PGN/DNA complexes may harbor the potential for development into efficient and safe gene delivery vehicles.     

Molecular basis of the differences between normal and tumor tissues of gastric cancer

To be able to describe the differences between the normal and tumor tissues of gastric cancer at a molecular level would be essential in the study of the disease. We investigated the gene expression pattern in the two types of tissues from gastric cancer by performing expression profiling of 86 tissues on 17K complementary DNA microarrays. To select for the differentially expressed genes, class prediction algorithm was employed. For predictor selection, samples were first divided into a training (n=58), and a test set (n=28). A group of 894 genes was selected by a t-test in a training set, which was used for cross-validation in the training set and class (normal or tumor) prediction in the test set. Smaller groups of 894 genes were individually tested for their ability to correctly predict the normal or tumor samples based on gene expression pattern. The expression ratios of the 5 genes chosen from microarray data can be validated by real time RT-PCR over 6 tissue samples, resulting in a high level of correlation, individually or combined. When a representative predictor set of 92 genes was examined, pathways of 'focal adhesion' (with gene components of THBS2, PDGFD, MAPK1, COL1A2, COL6A3), 'ECM-receptor interaction' pathway (THBS2, COL1A2, COL6A3, FN1) and 'TGF-beta signaling' (THBS2, MAPK1, INHBA) represent some of the main differences between normal and tumor of gastric cancer at a molecular level.     

Imperfect mimicry of host begging calls by a brood parasitic cuckoo: a cue for nestling rejection by hosts?

Coevolutionary interactions between avian brood parasites and their hosts often lead to the evolution of discrimination and rejection of parasite eggs or chicks by hosts based on visual cues, and the evolution of visual mimicry of host eggs or chicks by brood parasites. Hosts may also base rejection of brood parasite nestlings on vocal cues, which would in turn select for mimicry of host begging calls in brood parasite chicks. In cuckoos that exploit multiple hosts with different begging calls, call structure may be plastic, allowing nestlings to modify their calls to match those of their various hosts, or fixed, in which case we would predict either imperfect mimicry or divergence of the species into host-specific lineages. In our study of the little bronze-cuckoo (LBC) Chalcites minutillus and its primary host, the large-billed gerygone Gerygone magnirostris, we tested whether: (1) hosts use nestling vocalizations as a cue to discriminate cuckoo chicks; (2) cuckoo nestlings mimic the host begging calls throughout the nestling period; and (3) the cuckoo begging calls are plastic, thereby facilitating mimicry of the calls of different hosts. We found that the begging calls of LBCs are most similar to their gerygone hosts shortly after hatching (when rejection by hosts typically occurs) but become less similar as cuckoo chicks get older. Begging call structure may be used as a cue for rejection by hosts, and these results are consistent with gerygone defenses selecting for age-specific vocal mimicry in cuckoo chicks. We found no evidence that LBC begging calls were plastic.     

Production and partial characterization of biosurfactant produced by Streptomyces sp. R1

The present study focused on developing a wild-type actinomycete isolate as a model for a non-pathogenic filamentous producer of biosurfactants. A total of 33 actinomycetes isolates were screened and their extracellular biosurfactants production was evaluated using olive oil as the main substrate. Out of 33 isolates, 32 showed positive results in the oil spreading technique (OST). All isolates showed good emulsification activity (E₂₄) ranging from 84.1 to 95.8%. Based on OST and E₂₄ values, isolate R1 was selected for further investigation in biosurfactant production in an agitated submerged fermentation. Phenotypic and genotypic analyses tentatively identified isolate R1 as a member of the Streptomyces genus. A submerged cultivation of Streptomyces sp. R1 was carried out in a 3-L stirred-tank bioreactor. The influence of impeller tip speed on volumetric oxygen transfer coefficient (k _L a), growth, cell morphology and biosurfactant production was observed. It was found that the maximum biosurfactant production, indicated by the lowest surface tension measurement (40.5 ± 0.05 dynes/cm) was obtained at highest k _L a value (50.94 h⁻¹) regardless of agitation speed. The partially purified biosurfactant was obtained at a concentration of 7.19 g L⁻¹, characterized as a lipopeptide biosurfactant and was found to be stable over a wide range of temperature (20–121 °C), pH (2–12) and salinity [5–20% (w/v) of NaCl].

     

Molecular authentication of two medicinal plants <Emphasis Type="Italic">Ligularia fischeri</Emphasis> and <Emphasis Type="Italic">Ligularia stenocephala</Emphasis> using allele-specific PCR (AS-PCR) strategy

Ligularia fischeri (Gom-chi) and Ligularia stenocephala (Gon-dal-bi) are popular edible herbs in Korea. L. fischeri is used to treat jaundice, hepatitis, rheumatoid arthritis, and scarlet fever, while L. stenocephala is used to treat anxiety, weakness, and menstrual disorders. The herbal medicinal activities of these two herbs differ, but they are very difficult to distinguish based on their morphologies, especially in their dried forms. In an effort to distinguish these two plant species, we sequenced three barcoding genes in plastids, matK, rbcL, and trnH-psbA. From the analysis of sequence variations, we detected five single nucleotide polymorphisms (SNPs) between two the species. Allele specific (AS)-primers in the SNPs were employed in discrimination of the two species. Of the five AS-primer sets, one primer pair in matK gene showed reproducibly distinguishable PCR amplification between plants of L. fischeri and L. stenocephala. The method is reproducible and efficient, and is the first reported molecular method to discriminate between L. fischeri and L. stenocephala.