Sword Bean (Canavalia gladiata) Pods Induce Differentiation in MC3T3-E1 Osteoblast Cells by Activating the BMP2/SMAD/RUNX2 Pathway

Sword bean (SB) contains various phytochemicals, such as flavonoids, tannins, saponins, and terpenoids. Although the evaluation of its potential functions, including antioxidant, anti-obesity, anti-inflammatory, liver protection, and antiangiogenic activities, has been widely reported, research on their use in osteoporosis prevention is insufficient. Furthermore, while various studies are conducted on SB, research on sword bean pods (SBP) is not yet active, and little is known about it. Therefore, this study investigated the effects of promoting osteoblast differentiation of MC3T3-E1 cells using SB and SBP extracts and their mechanisms. We show that SBP extracts increase osteoblast proliferation, mineralization-activated alkaline phosphatase (ALP), and collagen synthesis activities. Additionally, treatment with SBP extract increased the expression of markers related to osteoblast differentiation, such as ALP, SPARC, RUNX2, COL-I, BMP2, OCN, and OPN. It was confirmed that SBP induces differentiation by activating the BMP2/SMAD/RUNX2 pathway. We also show that SBP is more effective than SB, and SBP may be useful in assimilating bone minerals and preventing osteoporosis.

Ferulic Acid as a Protective Antioxidant of Human Intestinal Epithelial Cells

The intestinal epithelial barrier is the primary and most significant defense barrier against ingested toxins and pathogenic bacteria. When the intestinal epithelium barrier is breached, inflammatory response is triggered. GWAS data showed that endoplasmic reticulum (ER) stress markers are elevated in Inflammatory Bowel Disease (IBD) patients, which suggests ER stress regulation might alleviate IBD symptoms. Ferulic acid (FA) is a polyphenol that is abundant in plants and has antioxidant and anti-inflammatory properties, although it is unclear whether FA has these effects on the intestine. Therefore, we investigated the effect of FA in vitro and in vivo. It was found that FA suppressed ER stress, nitric oxide (NO) generation, and inflammation in polarized Caco-2 and T84 cells, indicating that the ER stress pathway was implicated in its anti-inflammatory activities. The permeability of polarized Caco-2 cells in the presence and absence of proinflammatory cytokines were decreased by FA, and MUC2 mRNA was overexpressed in the intestines of mice fed a high-fat diet (HFD) supplemented with FA. These results suggest that FA has a protective effect on intestinal tight junctions. In addition, mouse intestine organoids proliferated significantly more in the presence of FA. Our findings shed light on the molecular mechanism responsible for the antioxidant effects of FA and its protective benefits on the health of the digestive system.

Immature sword bean pods (Canavalia gladiata) inhibit adipogenesis in C3H10T1/2 cells and mice with high-fat diet-induced obesity

BACKGROUND

Sword bean (SB; Canavalia gladiata) is a perennial vine used as a food and medicinal plant in Asia. SB is rich in nutrients, such as flavonoids and urease, and has various functions, including beneficial effects on dysentery, nausea, and hemorrhoids, as well as anti-inflammatory and antioxidant activity. Various plant parts are used; however, little is known about the physiological effects of SB pods (SBP). In this study, the anti-obesity effects of SBP extract were evaluated.

METHODS

To investigate the anti-obesity effects of SBP extract, we confirmed the SBP extract downregulated lipogenesis-related genes and upregulated genes involved in lipolysis and brown adipocyte markers in differentiated C3H10T1/2 adipocytes in vitro. Next, we use a high-fat diet (HFD)-induced obesity mouse model to determine the anti-obesity effects of SBP extract.

RESULTS

Treatment with SBP extract significantly reduced adipocytes. The extract decreased the HFD-induced increases in body weight and plasma triglyceride levels in mice after 8 weeks. mRNA and protein levels of the adipogenesis and lipogenesis-related factors CCAAT/enhancer binding protein-β, CCAAT/enhancer binding protein-α, peroxisome proliferator-activated receptor-γ (PPARγ), and their target genes Ap2, SREBP-1c, FAS, and SCD-1 were reduced by SBP extract. In contrast, AMP-activated protein kinase and sirtuin1, involved in the thermogenic catabolism of fat, were activated by SBP extract in adipocytes and white adipose tissue, increasing the expression of peroxisome proliferator-activated receptor gamma coactivator-1α, peroxisome proliferator-activated receptor-α (PPARα), and uncoupling protein 1 and activating thermogenic activity.

CONCLUSION

SBP extract exerts an anti-obesity effect by inhibiting lipogenesis-related factors and activating fat-catabolizing factors; it is, therefore, a promising functional food and natural anti-obesity agent.

Fermentation of Chestnut (Catanea crenata Sieb) Inner Shell Enhances Anti-Obesity Effects in 3T3-L1 and C3H10T1/2 Adipocytes

Chestnut inner shell (CIS) is rich in phenols and flavonoids such as gallic acid and ellagic acid, which are known to exhibit effective antioxidant and anti-obesity properties. Fermentation using lactic acid bacteria can enhance the physiological activity by increasing the contents of such functional ingredients. In this study, we evaluated the anti-obesity effects of a CIS extract subjected to a fermentation process (fermented CIS [FCIS]). Treatment with CIS and FCIS extracts (125, 250, and 500 μg/mL) increased cell viability and did not induce apoptosis, indicating no toxicity. The extract suppressed the gene expression of adipogenic factors, peroxisome proliferation-activated receptor gamma, CCAAT/enhancer binding protein (C/EBP) alpha, and C/EBP beta (by 7.75% and 67.59%, 21.41% and 66.27% in 500 μg/mL, respectively), and consequently suppressed the expression of downstream lipogenic factors such as fatty acid synthase, stearoyl CoA desaturase-1, citrate synthase, and ATP citrate lyase. The expression of factors involved in fat catabolism and β-oxidation increased in a dose-dependent manner, thereby preventing fat accumulation. This observation was consistent with the significant decrease in the staining intensity for lipid droplets, which indicated that lipid accumulation was decreased by 15.46% and 29.44% in 3T3L-1 and 27.01% and 46.68% in C3H10T1/2. Together, these results demonstrate the higher anti-obesity effects of FCIS extract than that of CIS extract, indicating the potential applicability of FCIS as an effective natural raw material to curb obesity.

Anti-Inflammatory Effect of Immature Sword Bean Pod (Canavalia gladiata) in Lipopolysaccharide-Induced RAW264.7 Cells

Sword bean has been known as a traditional medicinal plant to treat cancer, sinus infection, and suppurative disease. It also possesses hypertension-relieving, antioxidation, and antibacterial effects. However, studies on the efficacy of sword bean are limited to mature beans. Few studies have focused on immature sword bean pod (ISBP). Therefore, this study aimed to investigate the anti-inflammatory effect of ISBP in RAW264.7 cells stimulated with lipopolysaccharide (LPS). After LPS-induced RAW264.7 cells were treated with ISBP at concentrations (0.5, 1, 2, and 5 mg/mL), levels of nitrite oxide (NO) and prostaglandin E2 (PGE2) production, protein, and mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), inflammatory cytokine secretion level, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity were determined. Under inflammatory conditions induced by LPS, ISBP reduced levels of inflammatory mediators NO and PGE2 by 60% and 23%, respectively. It also decreased protein and mRNA expression levels of iNOS and COX-2 known to synthesize inflammatory mediators. Inflammatory cytokines, interleukin (IL)-6, and IL-1β, levels were decreased, while interferon gamma level was increased by ISBP based on enzyme-linked immunosorbent assay (ELISA) and real time-polymerase chain reaction results. Finally, ISBP showed the ability to inhibit NF-κB activity. In conclusion, ISBP can alleviate inflammation by controlling inflammation-related substances, and may have efficacy as a healthful functional food and natural anti-inflammatory drug.

Antioxidant Effect of Lycium barbarum Leaf through Inflammatory and Endoplasmic Reticulum Stress Mechanism

Although the prevalence and incidence of inflammatory bowel disease (IBD), a defective immune response of the gastrointestinal tract, has been increasing in North America and Western Europe, recent studies have shown that this disease is also increasing rapidly in Asia. Several studies have been searching for functional foods that can prevent or reduce IBD symptoms because the drug treatments for IBD are expensive with complications. Genome-Wide Association Study (GWAS), an observational study of a genome-wide set of genetic variants in different individuals, showed that endoplasmic reticulum (ER) stress is one of the causes of IBD. Previously, we reported the effects of Lyciumbarbarum fruit and this study investigated the effects of Lycium barbarum leaf (LL) on inflammation and ER stress of the intestine. The paracellular permeability, antioxidant, and anti-inflammatory response were measured on polarized Caco-2 cells. The ER stress pathway and pro-inflammatory cytokines were evaluated on MEF-knockout cell lines, and on the intestines of the mice fed a high-fat diet with lipopolysaccharide-induced inflammation. Our data showed that the LL pretreatment strengthened the tight junction integrity and reduced NO production both in the presence and in the absence of inflammation. Furthermore, LL inhibited ER stress and inflammation via IRE1α and XBP1 in vitro as well as in the inflamed intestines of mice, highlighting the antioxidant and anti-inflammatory function of LL in an IRE1α-XBP1-dependent manner.

Anti-inflammatory effect of Lycium barbarum on polarized human intestinal epithelial cells

BACKGROUND/OBJECTIVES

Inflammatory Bowel Disease (IBD) has rapidly escalated in Asia (including Korea) due to increasing westernized diet patterns subsequent to industrialization. Factors associated with endoplasmic reticulum (ER) stress are demonstrated to be one of the major causes of IBD. This study was conducted to investigate the effect of Lycium barbarum (L. barbarum) on ER stress.

MATERIALS/METHODS

Mouse embryonic fibroblast (MEF) cell line and polarized Caco-2 human intestinal epithelial cells were treated with crude extract of the L. chinense fruit (LF). Paracellular permeability was measured to examine the effect of tight junction (TJ) integrity. The regulatory pathways of ER stress were evaluated in MEF knockout (KO) cell lines by qPCR for interleukin (IL) 6, IL8 and XBP1 spliced form (XBP1s). Immunoglobulin binding protein (BiP), XBP1s and CCAAT/enhancer-binding homologous protein (CHOP) expressions were measured by RT-PCR. Scanning Ion Conductance Microscopy (SICM) at high resolution was applied to observe morphological changes after treatments.

RESULTS

Exposure to LF extract strengthened the TJ, both in the presence and absence of inflammation. In polarized Caco-2 pretreated with LF, induction in the expression of proinflammatory marker IL8 was not significant, whereas ER stress marker XBP1s expression was significantly increased. In wild type (wt) MEF cells, IL6, CHOP and XBP1 spliced form were dose-dependently induced when exposed to 12.5–50 µg/mL extract. However, absence of XBP1 or IRE1α in MEF cells abolished this effect.

CONCLUSION

Results of this study show that LF treatment enhances the barrier function and reduces inflammation and ER stress in an IRE1α-XBP1-dependent manner. These results suggest the preventive effect of LF on healthy intestine, and the possibility of reducing the degree of inflammatory symptoms in IBD patients.

Immobilization of phenol-containing molecules on self-assembled monolayers on gold via surface chemistry

Various phenol-containing molecules such as flavonoids have a wide range of biological effects including anticancer, antimicrobial, and anti-inflammatory properties, and, therefore, they have become subjects of active research for various medicinal and biological applications. To construct applicable materials incorporated with phenol-containing molecules, strategies for immobilization of phenol-containing molecules on solid substrates are required. Although several immobilization methods have been devised and reported, mostly harnessing phenol functionality, however, development of a general immobilization method has been hampered due to its complicated chemical reactions and low reaction yields on surfaces. Furthermore, the use of phenol as a reaction center may compromise the biological activity of phenol-containing molecules. Here, we describe a simple, fast, and reliable method for the surface immobilization of phenol-containing molecules by introducing chemical functional groups, carboxylic acid, thiol, and azide, while maintaining phenol functionality by way of the Mannich-type condensation reaction. We examined the chemical functionalization of naphthol, tyrosine, and flavanone and their immobilization to the self-assembled monolayers on gold via various surface chemistries: the carbodiimide coupling reaction, Michael addition, and the 'click' reaction. We strongly believe our method can be a general and practical platform for immobilization of various phenol-containing molecules on surfaces of various materials.

Greenland records of aerosol source and atmospheric lifetime changes from the Eemian to the Holocene

The Northern Hemisphere experienced dramatic changes during the last glacial, featuring vast ice sheets and abrupt climate events, while high northern latitudes during the last interglacial (Eemian) were warmer than today. Here we use high-resolution aerosol records from the Greenland NEEM ice core to reconstruct the environmental alterations in aerosol source regions accompanying these changes. Separating source and transport effects, we find strongly reduced terrestrial biogenic emissions during glacial times reflecting net loss of vegetated area in North America. Rapid climate changes during the glacial have little effect on terrestrial biogenic aerosol emissions. A strong increase in terrestrial dust emissions during the coldest intervals indicates higher aridity and dust storm activity in East Asian deserts. Glacial sea salt aerosol emissions in the North Atlantic region increase only moderately (50%), likely due to sea ice expansion. Lower aerosol concentrations in Eemian ice compared to the Holocene are mainly due to shortened atmospheric residence time, while emissions changed little.

Past climate changes in Greenland ice were accompanied by large aerosol concentration changes. Here, the authors show that by correcting for transport effects, reliable source changes for biogenic aerosol from North America, sea salt aerosol from the North Atlantic, and dust from East Asian deserts can be derived.

Application of the biotin-labeled toxin mutant for affinity isolation of associated proteins in the mammalian cells

Cholera toxin (CT), one of the AB₅ bacterial toxin families, is produced by Vibrio cholerae, breeches the intestinal epithelial barrier and enters host epithelial cells to cause the massive secretory diarrhea. This study focused on understanding the retro-translocation machinery of the bacterial toxin using biotin-avidin technology to explain toxin trafficking from the endoplasmic reticulum (ER) to the cytosol. Because the association between the A1 chain of CT and other components of the retro-translocation machinery is likely transient or very weak, the successful bioengineering of such a mutant to be trapped as an intermediate in ER is essential for affinity isolation and further analysis. Here, we prepared a mutant toxin that 15 amino acid Biotin Acceptor Peptide (BAP) was fused to the C-terminal of A1 chain of CT. Biotinylation efficiency of the BAP-inserted cholera toxin (BT) was nearly 100%. Moreover, BT was functionally toxic and successfully pulled down by NeutrAvidin in vitro and in vivo. However, NeutrAvidin-bound biotinylated BT was not toxic. These results suggest the possibility of a plug effect of the biotin-NeutrAvidin-BT complex stuck in the ER without retro-translocation to the cytosol. Therefore, this model might identify the interacting proteins with A1 chain of CT in the host cells by holding the moment of retro-translocation of the bacterial toxin. In conclusion, this study established the model using biotin-avidin technology to elucidate the molecular basis for retro-translocation of bacterial toxin from within the lumen of ER to the cytosol.

Development of a death education curriculum model for the general public using DACUM method

In order to analyze tasks of the death education curriculum for the public, DACUM method was used. A committee for DACUM was gathered and a survey was conducted on professors of health care, humanities and social sciences for an interdisciplinary study. In the survey used to verify the model for death education for the public, a compilation based on difficulty and importance factor shows that the 27 tasks including the psychological changes in terminally ill or suicidal patients, healing of stress, acceptance and understanding of death and suicide prevention were identified as needing to be included in the curriculum. The data thus concluded will have to be reviewed when they are applied to actual education to revise the education program to make it more appropriate.

Feasibility of high-pitch dual-source low-dose chest CT: Reduction of radiation and cardiac artifacts

PURPOSE

To compare the radiation dose and image quality, focused mainly on cardiac pulsation artifact, between high-pitch low-dose chest computed tomography (HP-LDCT) and standard low-dose chest CT (LDCT).

PATIENTS AND METHODS

One hundred patients underwent HP-LDCT (50 patients) or LDCT (50 patients). Scan parameters were the same except for the pitch and gantry rotation time: 3.0 vs. 1.2 and 0.28s vs. 0.5s, respectively. Objective image noise at five regions and subjective image quality, such as noise, artifacts, cardiac pulsation artifacts, and overall diagnostic acceptability, were evaluated using a five-point scale. The significance level for all tests was set at P<0.05.

RESULTS

The dose-length products (DLPs) with HP-LDCT and LDCT were 90.2±4.3mGycm and 103.1±6.4mGycm, respectively (P<0.01). DLP of HP-LDCT showed a 13% reduction versus LDCT. Objective image noise was not significantly different. Cardiac pulsation artifacts showed a significant reduction on HP-LDCT (P<0.01). Other subjective image quality parameters of HP-LDCT were similar to those of LDCT. The overall diagnostic acceptability of HP-LDCT was better than that of LDCT (P<0.01).

CONCLUSIONS

HP-LDCT showed a 13% mean radiation dose reduction with no deterioration in image quality due to cardiac pulsation artifacts.

Enhanced gene transfer to pancreatic islets using glucagon-like peptide-1

OBJECTIVE

The efficient transfer of genes into intact islets is difficult since islets exist as clusters of differentiated cells with little replication potential. Cell proliferation in response to growth factors is known to be accompanied by loosening of cell-to-cell contacts and increasing paracellular permeability. In this study, we investigated whether gene delivery into intact islet cells was facilitated by modulating β-cell proliferation.

METHODS

Isolated rat islets were pretreated with glucagon-like peptide (GLP)-1 or human growth hormone for 24 hours, or with 300 mg/dL of glucose for 48 hours before transduction with a suboptimal dose of recombinant adenoviral vector expressing green fluorescent protein (GFP) and β-galactosidase (multiplicity of infection of 25). Transduction efficiency was assessed by measuring β-galactosidase activity and GFP expression using enzyme-linked immunosorbent assay, flow cytometry, and fluorescence microscopy. The numbers of 7-aminoactinomycin D-positive dead cells and 5-ethynyl-2-deoxyuridine (EdU)-positive proliferating cells were also monitored using flow cytometry and fluorescence microscopy.

RESULTS

The transduction efficiency of rat islet cells by a suboptimal dose of viral vector was significantly improved by GLP-1 pretreatment, accompanied by enhanced cell viability and cell proliferation. An increased GFP expression in islet cells after GLP-1 pretreatment was observed among the increased numbers of EdU-positive proliferating cells.

CONCLUSION

Pretreatment of rat islets with GLP-1 enhanced the transduction efficiency of an adenoviral vector, reducing viral dose burden while improving islet cell viability. From a therapeutic standpoint, genetic modification of pancreatic islets combined with GLP-1 pretreatment may be a promising option for ex vivo gene therapy prior to islet transplantation.

Nano-electromechanical switch-CMOS hybrid technology and its applications

Si-based CMOS technology is facing a serious challenge in terms of power consumption and variability. The increasing costs associated with physical scaling have motivated a search for alternative approaches. Hybridization of nano-electromechanical (NEM)-switch and Si-based CMOS devices has shown a theoretical feasibility for power management, but a huge technical gap must be bridged before a nanoscale NEM switch can be realized due to insufficient material development and the limited understanding of its reliability characteristics. These authors propose the use of a multilayer graphene as a nanoscale cantilever material for a nanoscale NEM switchwith dimensions comparable to those of the state-of-the-art Si-based CMOS devices. The optimal thickness for the multilayer graphene (about five layers) is suggested based on an analytical model. Multilayer graphene can provide the highest Young's modulus among the known electrode materials and a yielding strength that allows more than 15% bending. Further research on material screening and device integration is needed, however, to realize the promises of the hybridization of NEM-switch and Si-based CMOS devices.

Protective effects of a polysaccharide from Hizikia fusiformis against ethanol toxicity in rats

Hizikia fusiformis is an edible brown alga that is widely consumed in Korea, Japan, and China and possesses a number of potentially beneficial compounds, including antioxidants and anticoagulants. No reports have investigated potential H. fusiformis protectants against ethanol-induced peptic injury. We extracted a polysaccharide from H. fusiformis (Hf-PS-1) that exhibited protective effects against ethanol-induced peptic injury and related mechanisms in rats. Experimental animals were divided into three groups: control, ethanol-only, and ethanol+Hf-PS-1. The ethanol-only group exhibited decreased levels of total glutathione (GSH) and increased levels of jun N-terminal kinase (JNK) phosphorylation relative to the control group, whereas levels were significantly increased and decreased, respectively, in the ethanol+Hf-PS-1 group. The ethanol-only group also exhibited increased levels of extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation relative to the control group; these levels were not significantly different in the ethanol+Hf-PS-1 group. Hf-PS-1 appeared to reduce ethanol-induced gastric injury. Therefore, we suggest that Hf-PS-1 could protect against ethanol-induced peptic ulcers primarily through a mechanism associated with the inhibition of JNK activation.

Effect of a glycoprotein from Hizikia fusiformis on acetaminophen-induced liver injury

In this study, we isolated a glycoprotein from the brown alga Hizikia fusiformis (HFGP) and examined whether it could protect against Acetaminophen (AAP)-induced liver injury in vivo and in vitro. AAP, one of the most commonly abused drugs, may cause fatal liver injury. An analysis of the effects of HFGP on AAP toxicity in rats revealed that the serum glutamic pyruvic transaminase level was restored to the control level and glutathione level was also increased by co-treatment with HFGP and AAP. Furthermore, HFGP co-treatment decreased caspase-3/-9 activity. These results indicate that HFGP may inhibit AAP-induced liver injury in Sprague-Dawley rats. Several lines of evidence indicate that oxidative stress plays an important role in AAP-induced liver injury and mitogen-activated protein kinase (MAPK) signaling is involved in the regulation of oxidative stress. Therefore, Western blotting was used to determine which MAPK signaling pathway is involved in the protective effect of HFGP against AAP toxicity in HepG2 cells. We found that ERK activation was involved in the protective effect of HFGP against AAP-induced cell death. Therefore, we propose that MAPK signaling is involved in the protective effect of HFGP against AAP-induced liver injury.

Inhibitory effect of amygdalin on lipopolysaccharide-inducible TNF-alpha and IL-1beta mRNA expression and carrageenan-induced rat arthritis

Amygdalin is a cyanogenic glycoside plant compound found in the seeds of rosaceous stone fruits. We evaluated the antiinflammatory and analgesic activities of amygdalin, using an in vitro lipopolysaccharide (LPS)-induced cell line and a rat model with carrageenan-induced ankle arthritis. One mM amygdalin significantly inhibited the expression of TNF-alpha and IL-1beta mRNAs in LPS-treated RAW 264.7 cells. Amygdalin (0.005, 0.05, and 0.1 mg/kg) was intramuscularly injected immediately after the induction of carrageenan-induced arthritic pain in rats, and the anti-arthritic effect of amygdalin was assessed by measuring the weight distribution ratio of the bearing forces of both feet and the ankle circumference, and by analyzing the expression levels of three molecular markers of pain and inflammation (c-Fos, TNF-alpha, and IL-1beta) in the spinal cord. The hyperalgesia of the arthritic ankle was alleviated most significantly by the injection of 0.005 mg/kg amygdalin. At this dosage, the expressions of c-Fos, TNF-alpha, and IL-1beta in the spinal cord were significantly inhibited. However, at dosage greater than 0.005 mg/kg, the painrelieving effect of amygdalin was not observed. Thus, amygdalin treatment effectively alleviated responses to LPStreatment in RAW 264.7 cells and carrageenan-induced arthritis in rats, and may serve as an analgesic for relieving inflammatory pain.

Antinociceptive effect of amygdalin isolated from Prunus armeniaca on formalin-induced pain in rats

Amygdalin is a plant glucoside isolated from the stones of rosaceous fruits, such as apricots, peaches, almond, cherries, and plums. To investigate the pain-relieving activity of amygdalin, we induced pain in rats through intraplantar injection of formalin, and evaluated the antinociceptive effect of amygdalin at doses of 0.1, 0.5, 1.0, and 10.0 mg/kg-body weight by observing nociceptive behavior such as licking, biting and shaking, the number of Fos-immunoreactive neurons in the spinal cord, and the mRNA expression of inflammatory cytokines in the plantar skin. The intramuscular injection of amygdalin significantly reduced the formalin-induced tonic pain in both early (the initial 10 min after formalin injection) and late phases (10-30 min following the initial formalin injection). During the late phase, amygdalin did reduce the formalin-induced pain in a dose-dependent manner in a dose range less than 1 mg/kg. Molecular analysis targeting c-Fos and inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) also showed a significant effect of amygdalin, which matched the results of the behavioral pain analysis. These results suggest that amygdalin is effective at alleviating inflammatory pain and that it can be used as an analgesic with anti-nociceptive and anti-inflammatory activities.

The effect of polysaccharide extracted from the marine alga Capsosiphon fulvescens on ethanol administration

Seaweed extracts have recently been found to have antioxidant and antitumor activities. Capsosiphon fulvescens (Cf) is a green alga and nutrient-dense food source. In a previous study, we extracted polysaccharide from Cf (Cf-PS) and demonstrated its antitumor effect in gastric cancer cells. In this report, we describe the protective effect of Cf-PS against alcohol-induced gastric injury in rats and adenocarcinoma (AGS) cells. In vivo assay revealed stomach damage in rats treated with alcohol alone; however, the stomach condition of rats co-treated with Cf-PS and alcohol matched that of the control group. Cf-PS also inhibited alcohol-induced cell death in AGS cells. Compared with alcohol treatment alone, Cf-PS and alcohol co-treatment increased phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt but inhibited poly-ADP-ribose polymerase (PARP) cleavage. Thus, ERK1/2 and Akt activation are instrumental in the protective effect of Cf-PS against alcohol-induced cell death in AGS cells. Moreover, Cf-PS treatment reduced the expressions of cyclooxygenase-2 (COX-2) and the inducible form of nitric oxide (iNOS), proteins related to ulcers. These results suggest that Cf-PS could help protect against alcohol-induced peptic ulcers.

Optimization of submerged culture condition for the production of mycelial biomass and exopolysaccharides by Agrocybe cylindracea

The optimization of submerged culture conditions and nutritional requirements was studied for the production of exopolysaccharide (EPS) from Agrocybe cylindracea ASI-9002 using the statistically based experimental design in a shake flask culture. Both maximum mycelial biomass and EPS were observed at 25 degrees C. The optimal initial pH for the production of mycelial biomass and EPS were found to be pH 4.0 and pH 6.0, respectively. Subsequently, optimum concentration of each medium component was determined using the orthogonal matrix method. The optimal combination of the media constituents for mycelial growth was as follows: maltose 80 g/l, Martone A-1 6 g/l, MgSO4 x 7H2O 1.4 g/l, and CaCl2 1.1 g/l; for EPS production: maltose 60 g/l, Martone A-1 6 g/l, MgSO4 x 7H2O 0.9 g/l, and CaCl2 1.1 g/l. Under the optimal culture condition, the maximum EPS concentration achieved in a 5-l stirred-tank bioreactor indicated 3.0 g/l, which is about three times higher than that at the basal medium.

Morphological and rheological properties of the three different species of basidiomycetes Phellinus in submerged cultures

AIMS

The objective of this work was to investigate the morphological and rheological properties in submerged culture of the three different basidiomycetes Phellinus (P. baumii, P. gilvus and P. linteus) that produce pharmacologically important exopolysaccharides (EPS).

METHODS AND RESULTS

In flask cultures, pH proved to be a critical factor affecting mycelial growth, morphological change and EPS production. The macroscopic morphologies observed under different pHs in flask cultures were also comparable: i.e. starfish-like pellets with a lesser extent of free mycelium appeared in P. baumii, whereas smooth pellets with higher amounts of free mycelium were observed in P. gilvus and P. linteus. The pelleted fermentations were further characterized in a 5-l stirred-tank fermenter by image analysis with respect to mean diameter, core area and pellet circularity. Phellinus baumii showed the largest pellet size (5.2 mm in diameter), whereas P. linteus had extremely small and spherical pellets. The culture broth of P. baumii and P. gilvus yielded extremely high apparent viscosities, ranging from 5 to 7 Pa s.

CONCLUSIONS

Three important species of Phellinus showed significantly different morphological and rheological properties. The morphological variation of the three Phellinus species was closely linked to EPS productivity and the apparent viscosity of the whole broth.

SIGNIFICANCE AND IMPACT OF THE STUDY

The morphological change in the three species of Phellinus was a good indicator for identifying cell activity for EPS production. Our finding may be beneficial for further optimization of other fungal fermentation processes for large-scale production of EPS.

Production and molecular characteristics of four groups of exopolysaccharides from submerged culture of Phellinus gilvus

AIMS

The objective of the present study was to determine the optimal culture conditions for the production of four groups of exopolysaccharides (EPSs) in Phellinus gilvus by submerged culture and to investigate their molecular properties by multi-angle laser-light scattering (MALLS) analysis.

METHODS AND RESULTS

The optimal temperature and initial pH for the production of both mycelial biomass and EPSs in P. gilvus by submerged flask cultures were found to be 30 degrees C and pH 9.0, respectively. Glucose and corn steep powder were the most suitable carbon and nitrogen source for both mycelial biomass and EPS production. Optimal medium composition was determined to be glucose 30 g l-1, corn steep powder 5 g l-1, MgSO4 1.23 g l-1, KH2PO4 0.68 g l-1, and K2HPO4 0.87 g l-1. Four groups of EPSs (Fr-I, II, III, and IV) were obtained from the culture filtrates by gel filtration chromatography on Sepharose CL-4B and characterized by size exclusion chromatography (SEC) coupled with MALLS. The weight average molar mass (Mw) of Fr-I, Fr-II, Fr-III and Fr-IV were determined to be 8.628 x 106 (+/-129 420), 1.045 x 106 (+/-19 855), 61.09 x 104 (+/-1244), and 33.55 x 104 (+/-134) g mol-1, respectively.

CONCLUSIONS

Under optimal culture conditions, the maximum EPS production in a 5-l stirred fermenter indicated 5.3 g l-1 after 11 days of fermentation. The SEC/MALLS analysis revealed that Fr-I, which has extremely high molecular weight, was presumably an aggregate of complex polysaccharides forming a compact globular shape; whereas Fr-II was nearly spherical, Fr-III and Fr-IV were rod-like chains in an aqueous solution.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on the production of high amounts of EPSs from liquid-culture of the basidiomycete, P. gilvus. The SEC/MALLS approach used in this study could be useful in providing greater insight into the characterization of the mushroom polysaccharides without carrying out elaborate fractionation procedures prior to analysis.

Effect of aeration and agitation on the production of mycelial biomass and exopolysaccharides in an enthomopathogenic fungus Paecilomyces sinclairii

AIMS

The objective of the present study was to investigate the influence of aeration rate and agitation intensity on the production of mycelial biomass and exopolysaccharide (EPS) in Paecilomyces sinclairii.

METHODS AND RESULTS

The P. sinclairii was cultivated under various aeration and agitation conditions in a 5 l stirred-tank bioreactor. The highest mycelial biomass (30.5 g l-1) and EPS production (11.5 g l-1) were obtained at a high aeration rate (3.5 v.v.m.) and at a high agitation speed (250 rev min-1). The apparent viscosities (6000-8000 cP) of fermentation broth increased rapidly towards the end of fermentations at high aeration and agitation conditions.

CONCLUSIONS

The high level of dissolved oxygen achieved at a high aeration rate (3.5 v.v.m.) associated with higher hyphal density eventually resulted in enhanced EPS production. Agitation intensity was also proved to be a critical factor influencing on both the mycelial biomass and EPS production: high agitation speeds up to 250 rev min-1 were preferred to the yields of biomass and EPS production.

SIGNIFICANCE AND IMPACT OF THE STUDY

The critical effects of aeration and agitation in the culture process of P. sinclairii were found, which is widely applicable to other kinds of basidiomycetes or ascomycetes in their submerged culture processes.

Production of red pigment by submerged culture of Paecilomyces sinclairii

AIMS

From a survey of submerged culture of edible mushrooms, a high pigment-producing fungus Paecilomyces sinclairii was selected and its optimal culture conditions investigated.

METHODS AND RESULTS

The optimal culture conditions for pigment production were as follows: inoculum age, 3 d; temperature, 25 degrees C; initial pH, 6.0; carbon source, 1.5% (w/v) soluble starch; nitrogen source, 1.5% (w/v) meat peptone. Although addition of 10 mmol l(-1) CaCl2 to the culture medium slightly increased pigment production, most of the bio-elements examined had no notable or detrimental effect on pigment production.

CONCLUSIONS

Under the optimal conditions obtained in the flask culture tested, a ninefold increase in pigment production (4.4 g l(-1)) was achieved using a 5(-l) batch fermenter. Paecilomyces sinclairii secreted water-soluble red pigment into the culture medium. The pigment colour was strongly dependent on the pH of the solution: red at pH 3-4, violet at pH 5-9 and pink at pH 10-12.

SIGNIFICANCE AND IMPACT OF THE STUDY

The high concentration of pigment (4.4 g l(-1)) produced by P. sinclairii demonstrates the possibility of commercial production of pigment by this strain, considering its relatively high production yield and light stability.

Effect of agitation intensity on the exo-biopolymer production and mycelial morphology in Cordyceps militaris

AIMS

The influence of agitation intensity on Cordyceps militaris morphology and exo-biopolymer production was investigated in a 5 litre stirred vessel using a six-blade Rushton turbine impeller.

METHODS AND RESULTS

The mycelial morphology of C. militaris was characterized by means of image analysis, which included mean diameter, circularity, roughness and compactness of the pellets. The morphological parameters of the pellets grown under different stirring conditions were significantly different, which correspondingly altered exo-biopolymer production yields.

CONCLUSIONS

The compactness of the pellets was found to be the most critical parameter affecting exo-biopolymer biosynthesis; more compact pellets were formed at 150 rev min(-1) with maximum exo-biopolymer production (15 g l(-1)).

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study suggest that morphological change of pellets is a good indicator for identifying the cell activity for exo-biopolymer production.

Influence of nutritional conditions on the mycelial growth and exopolysaccharide production in Paecilomyces sinclairii

AIMS

The objective of the study was to optimize the submerged culture conditions for the production of exopolysaccharide from Paecilomyces sinclairii.

METHODS AND RESULTS

The optimal temperature and initial pH for exopolysaccharide production by Paecilomyces sinclairii in shake flask culture were found to be 30 degrees C and 6.0, respectively. Sucrose (60 g l(-1)) and corn steep powder (10 g l(-1)) were the most suitable carbon and nitrogen source for exopolysaccharide production.

CONCLUSIONS

Under optimal culture medium, the maximum exopolysaccharide concentration in a 5-l stirred-tank fermenter indicated 7.4 g l(-1), which was approximately three times higher than that in basal medium. The maximum specific growth rates (micro max) and yield coefficient (Y(P/S)) in the optimal culture medium was 0.16 h(-1) and 0.19, respectively.

SIGNIFICANCE AND IMPACT OF THE STUDY

The optimal culture conditions reported in this article can be widely applied to the processes for submerged cultures of other mushrooms.

Mycelial growth and exo-biopolymer production by submerged culture of various edible mushrooms under different media

AIMS

The effect of synthetic media on the submerged mycelial growth and exo-biopolymer production in various edible mushrooms was investigated in shake flask culture.

METHODS AND RESULTS

Among 19 mushrooms examined, the relatively high yield in mycelial biomass and exo-biopolymer production was achieved in potato malt peptone (PMP) medium. In particular, Ganoderma lucidum NO. 1 and Phellinus linteus KCTC 6190 showed favourable growth in PMP medium with exo-biopolymer concentration of 1170 and 1520 mg l(-1), respectively.

CONCLUSIONS

Enhanced exo-biopolymer production was achieved from Ganoderma lucidum NO. 1 and Phellinus linteus KCTC 6190 in a 5L batch fermentor, indicating approximately 5000 and 2410 mg l(-1), respectively.

SIGNIFICANCE AND IMPACT OF THE STUDY

The exo-biopolymer production and mycelial growth from various mushrooms were found to be strongly controlled by different complex media.

Isolation and properties of arginase from a shade plant, ginseng (Panax ginseng C.A. Meyer) roots

Arginase (EC 3.5.3.1) was purified to homogeneity from root tissues of three-year-old ginseng (Panax ginseng C.A. Meyer), shade plant, and was found to be an extraordinarily large molecule relatively stable to heat. The enzyme was decameric having a molecular mass of 352,000 Da, with an optimal temperature and pH of 60 degrees C and 9.5, respectively. Analogues of arginine could not replace it as substrate, and a cysteine residue is at or near the active site. Maximum activity was obtained with Mn(2+) and Co(2+) also activated the proteins, whereas, both agmatine and 5'-deoxy-methylthioadenosine were inhibitors. Specific activities of the enzyme in sliced ginseng roots were increased by plant hormones such as GA(3), IAA, kinetin and putrescine, whereas the activities of the purified enzyme were unaffected by putrescine. Increases in arginase activities by these plant hormones could affect metabolism of polyamine intracellularly.

Induction of G(2)/M phase arrest and apoptosis by a new synthetic anti-cancer agent, DW2282, in promyelocytic leukemia (HL-60) cells

We studied the effect of DW2282-,[(S)-(+)-4-phenyl-1-[N-(4-aminobenzoyl)-indoline-5-sulfonyl-4,5-dihydro-2-imidazolone].hydrochloride], a newly developed anti-cancer agent, on cell proliferation, cell cycle progression, and induction of apoptosis in human promyelocytic leukemia (HL-60) cells. DW2282, a diarylsulfonylurea compound, was cytotoxic to HL-60 cells, with an IC(50) of 1.0 microg/mL. Treatment with DW2282 fragmented DNA in a concentration- and time-dependent manner, suggesting that these cells underwent apoptosis. Flow cytometric analysis further confirmed that DW2282-treated HL-60 cells were hypodiploid, in terms of DNA content, and were arrested at the G(2)/M phase. The cell cycle arrest was reversible upon the removal of DW2282. HL-60 cells also underwent distinct morphological changes in response to DW2282 treatment, including the appearance of elongated cells with conical tails and other apoptotic characteristics. G(2)/M phase cell cycle arrest was accompanied by a decrease in the levels of cdc2, a protein that plays a critical role for progression through the G(2)/M phase. Treatment of HL-60 cells with DW2282 was also associated with decreased levels of the anti-apoptotic protein Bcl-2, activation of caspase-3, and proteolytic cleavage of poly(ADP-ribose) polymerase. Taken together, these results demonstrate that DW2282 dramatically suppressed HL-60 cell growth by inducing apoptosis after G(2)/M phase arrest. These findings are consistent with the possibility that G(2)/M phase arrest was mediated by the down-regulation of cdc2 levels in HL-60 cells. The data also suggest that DW2282 triggered apoptosis by decreasing Bcl-2 levels and activating caspase-3 protease. These results provide important new information towards understanding the mechanisms by which DW2282 and other diarylsulfonylureas mediate their therapeutic effects.

Identification and antioxidant activity of novel chlorogenic acid derivatives from bamboo (Phyllostachys edulis)

One known and two novel antioxidant compounds have been isolated from bamboo (Phyllostachys edulis). The butanol-soluble extract of the bamboo leaves was found to have a significant antioxidant activity, as measured by scavenging the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and the superoxide anion radical (O(2)(-)) in the xanthine/xanthine oxidase assay system. Antioxidant activity-directed fractionation of the extract led to the isolation and characterization of three structural isomeric chlorogenic acid derivatives: 3-O-(3'-methylcaffeoyl)quinic acid (1), 5-O-caffeoyl-4-methylquinic acid (2), and 3-O-caffeoyl-1-methylquinic acid (3). Compounds 2 and 3 were isolated and characterized for the first time from the natural products. In the DPPH scavenging assay as well as in the iron-induced rat microsomal lipid peroxidation system, compounds 2 (IC(50) = 8.8 and 19.2 microM) and 3 (IC(50) = 6.9 and 14.6 microM) showed approximately 2-4 times higher antioxidant activity than did chlorogenic acid (IC(50) = 12.3 and 28.3 microM) and other related hydroxycinnamates such as caffeic acid (IC(50) =13.7 and 25.5 microM) and ferulic acid (IC(50) = 36.5 and 56.9 microM). Among the three compounds, compound 1 yielded the weakest antioxidant activity, and the DPPH scavenging and lipid peroxidation inhibitory activity (IC(50) = 16.0 and 29.8 microM) was lower than those of chlorogenic and caffeic acids. All three compounds exhibited both superoxide scavenging activities and inhibitory effects on xanthine oxidase. Their superoxide anion (O(2)(-)) scavenging activities (IC(50) = 1, 4.3 microM; 2, 2.8 microM; and 3, 1.2 microM) were markedly stronger than those of ascorbic acid (IC(50) = 56.0 microM), alpha-tocopherol (IC(50) > 100 microM), and other test compounds, although their inhibition effects on xanthine oxidase may contribute to the potent scavenging activity. alpha-Tocopherol exerted a significant inhibitory effect (65.5% of the control) on superoxide generation in 12-O-tetradecanoylphorbol-13-acetate-induced human promyelocytic leukemia HL-60 cells, and compound 3 showed moderate activity (36.0%). On the other hand, other compounds including 1, 2, chlorogenic acid, and other antioxidants were weakly active (24.8-10.1%) in the suppression of superoxide generation.

Infrared laser spectroscopy of jet-cooled carbon clusters: structure of triplet C6

We report the first structural characterization of the triplet isomer of C6. Forty-one rovibrational/fine structure transitions in the nu 4(sigma u) antisymmetric stretch fundamental of the C6 cluster have been measured by diode laser absorption spectroscopy of a supersonic carbon cluster beam. The observed spectrum is characteristic of a centrosymmetric linear triplet state with cumulene-type bonding. The measured ground state rotational constant B0 = 0.048 479 (10)cm-1 and the effective bond length r(eff) = 1.2868 (1) angstroms are in good agreement with ab initio predictions for the linear triplet (3 sigma g-) state of C6.

Optimization of submerged culture conditions for the mycelial growth and exo-biopolymer production by Cordyceps militaris

AIMS

The objective of the present study was to determine the optimal culture conditions for exo-biopolymer production by Cordyceps militaris in shake flask culture.

METHODS AND RESULTS

The optimal temperature and initial pH for both mycelial growth and exo-biopolymer production by Cordyceps militaris in shake flask culture were found to be 20 degrees C and 6.0, respectively. Sucrose (40 g x l(-1)) and corn steep powder (10 g x l(-1)) were the most suitable carbon and nitrogen source for both mycelial growth and exo-biopolymer production.

CONCLUSION

Under optimal culture conditions, the maximum exo-biopolymer concentration in a 5-l jar fermenter indicated 10.3 g x l(-1), which was approximately three times higher than that in shake flask culture.

SIGNIFICANCE AND IMPACT OF THE STUDY

This process can have a significant impact on the industrial scale when sucrose and corn steep powder were used as carbon and nitrogen source.

Effects of gamma radiation on the allergenic and antigenic properties of milk proteins

This study was carried out to evaluate the application of food irradiation technology as a method for reducing milk allergies. Bovine alpha-casein (ACA) and beta-lactoglobulin (BLG) were used as milk proteins. Using milk-hypersensitive patients' immunoglobulin E (IgE) and rabbit IgGs individually produced to ACA and BLG, the changes of allergenicity and antigenicity of irradiated proteins were observed by competitive indirect enzyme-linked immunosorbent assay. Allergenicity and antigenicity of the irradiated proteins were changed with different slopes of the inhibition curves. The disappearance of the band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and increase of the turbidity showed that solubility of the proteins decreased by radiation, and this decrease might be caused by agglomeration of the proteins. These results indicated that epitopes on milk allergens were structurally altered by gamma irradiation.

Oxygen diffusive barriers of rat distal colon: role of subepithelial tissue, mucosa, and mucus gel layer

The contributions of subepithelial tissue, mucosa, and mucus gel layer as restraints for oxygen diffusion in rat distal colon in vitro were assessed by comparing oxygen transfer through preparations of isolated submucosa, isolated mucosa with and without the superficial mucus gel layer, and mucosa-submucosa mounted as flat sheets in a diffusion chamber. One side of the chamber was gassed with 95% O2-5% CO2 while the time course of oxygen concentration rise was measured in the continuously stirred opposite side, initially equilibrated with near-zero oxygen solution. The procedure does not affect epithelial viability. Diffusion in isolated mucosa was the same before and after KCN (5 mM) treatment, suggesting that epithelial oxygen consumption does not influence transfer rates. Subepithelial tissue, mucosa, and mucus gel layer are roughly responsible, respectively, for 12%, 56%, and 32% of oxygen diffusive hindrance. Diffusion coefficients range from 13% (mucosa-submucosa) to 54% (isolated submucosa) of that of water. Subepithelial tissue accounts for about 12% of total diffusive restraint.

Occurrence of aflatoxin M1 in Korean dairy products determined by ELISA and HPLC

The occurrence of aflatoxin M1 (AFM1) in pasteurized milk and dairy products was investigated by using direct competitive enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC). The recoveries of AFM1 from the samples spiked at levels between 5 and 500 pg/ml were 88.0-106.5% for pasteurized milk and 84.0-94.0% for yoghurt by ELISA. By HPLC, the recoveries were 103-120% for pasteurized milk and 87.0-93.0% for yoghurt. The limits of detection were found to be 2 pg/ml by ELISA and 10 pg/ml by HPLC. Among a total of 180 samples collected in Seoul, Korea, the incidence of AFM1 in pasteurized milk, infant formula, powdered milk and yoghurt was 76, 85, 75, and 83%, respectively, with a mean concentration of 18, 46, 200, and 29 pg/g, respectively, when determined by ELISA. These results obtained by ELISA were closely related to those by HPLC for AFM1 (r2 = 0.9783).

A radioimmunoassay method for detection of DNA based on chemical immobilization of anti-DNA antibody

High selectivity provided by biomolecules such as antibodies and enzymes has been exploited during the last two decades for development of biosensors. Of particular importance are efficient immobilization methods for biomolecules in order to preserve their biological activities. In this study, we have evaluated immobilization strategies for an anti-DNA antibody on a self-assembled monolayer of omega-functionalized thiols. The antibody was immobilized via peptide bond formation between the primary amines in the antibody and the carboxyl groups on the self-assembled monolayer. The peptide bond coupling was achieved by activating COOH groups on the surface through N-Hydroxysuccimide (NHS)-ester formation, followed by acylation of NH2 group in the antibody. DNA binding activity of the immobilized antibody was examined by counting beta emission from 35S-labeled DNA.

Analysis of Corynebacterium glutamicum methionine biosynthetic pathway: isolation and analysis of metB encoding cystathionine gamma-synthase

The metB gene encoding cystathionine y-synthase, the second enzyme of methionine biosynthetic pathway, was isolated from a pSL109-based Corynebacterium glutamicum gene library via complementation of an Escherichia coli metB mutant. A DNA-sequence analysis of the cloned DNA identified an open-reading frame of 1161 bp which encodes a protein with the molecular weight of 41,655 comprising of 386 amino acids. The putative protein product showed good amino acid-sequence homology to its counterpart in other organisms. Introduction of a plasmid carrying the cloned metB into the C. glutamicum resulted in a 10-fold increase in cystathionine gamma-synthase activities, demonstrating the identity of the cloned gene. The C. glutamicum metB mutant which was generated by the site-specific integration of the cloned DNA into its chromosome did not lose the ability to grow on glucose minimal medium lacking supplemental methionine. The growth rate of the mutant strain was also comparable to that of the parental strain. These data indicate that, in addition to the transsulfuration pathway, other methionine biosynthetic pathways may be present in C. glutamicum.

Nrg1 is a transcriptional repressor for glucose repression of STA1 gene expression in Saccharomyces cerevisiae

Expression of genes encoding starch-degrading enzymes is regulated by glucose repression in the yeast Saccharomyces cerevisiae. We have identified a transcriptional repressor, Nrg1, in a genetic screen designed to reveal negative factors involved in the expression of STA1, which encodes a glucoamylase. The NRG1 gene encodes a 25-kDa C2H2 zinc finger protein which specifically binds to two regions in the upstream activation sequence of the STA1 gene, as judged by gel retardation and DNase I footprinting analyses. Disruption of the NRG1 gene causes a fivefold increase in the level of the STA1 transcript in the presence of glucose. The expression of NRG1 itself is inhibited in the absence of glucose. DNA-bound LexA-Nrg1 represses transcription of a target gene 10.7-fold in a glucose-dependent manner, and this repression is abolished in both ssn6 and tup1 mutants. Two-hybrid and glutathione S-transferase pull-down experiments show an interaction of Nrg1 with Ssn6 both in vivo and in vitro. These findings indicate that Nrg1 acts as a DNA-binding repressor and mediates glucose repression of the STA1 gene expression by recruiting the Ssn6-Tup1 complex.

Emotional and behavioural problems in primary school children from nuclear and extended families in Korea

The changes occurring within Korean society provide an opportunity for studying the influence of family structure on children's emotional and behavioural problems. Children aged 7-13 years from two Korean cities were assessed for emotional and behavioural problems in school by their teachers, using the Children's Behaviour Questionnaire. In Study 1, 326 children from extended families were compared with demographically matched nuclear family children in the same school classes. In Study 2, a further sample of 204 extended family children was compared with pair-matched nuclear family children, in order to replicate the findings. Children from Study 1 were followed up 2.5 years later. Children from extended families had lower behaviour problems scores and the prevalence of serious problems was lower in extended family children. These differences were most marked in relation to externalising behaviour problems and were stable over the studies and time. Grandparents in extended families may increase children's resiliency by providing sources of attachment, affection, and knowledge, as well as having indirect effects through their support of parents. Consistent with recent ideas about the cognitive bases for behaviour problems, it may be that rules for behaviour derived from traditional cultural beliefs and values are internalised by children from extended families and generalise to prevent behaviour problems in school.

Characterization of silicon-carbon clusters by infrared laser spectroscopy: the nu 3(sigma u) band of linear Si2C3

The nu 3(sigma u) fundamental vibration of 1 sigma g+ Si2C3 has been observed using a laser vaporization-supersonic cluster beam-diode laser spectrometer. Forty rovibrational transitions were measured in the range of 1965.8 to 1970.9 cm-1 with a rotational temperature of 10-15 K. A least-squares fit of these transitions yielded the following molecular constants: nu 3(sigma u)=1968.188 31(18) cm-1, B"=0.031 575 1(60) cm-1, and B'=0.031 437 4(57) cm-1. These results are in excellent agreement with recent Fourier transform infrared (FTIR) measurements of Si2C3 trapped in a solid Ar matrix [J. Chem. Phys. 100, 181(1994)] and with ab initio calculations [J. Chem. Phys. 100, 175 (1994)] which suggest cumulenic-like bonding for Si2C3, analogous to the isovalent C5 carbon cluster.

Infrared laser spectroscopy of the linear C13 carbon cluster

The infrared absorption spectrum of a linear, 13-atom carbon cluster (C13) has been observed by using a supersonic cluster beam-diode laser spectrometer. Seventy-six rovibrational transitions were measured near 1809 wave numbers and assigned to an antisymmetric stretching fundamental in the 1 sigma g+ ground state of C13. This definitive structural characterization of a carbon cluster in the intermediate size range between C10 and C20 is in apparent conflict with theoretical calculations, which predict that clusters of this size should exist as planar monocyclic rings.

Infrared laser spectroscopy of jet-cooled carbon clusters: the bending dynamics of linear C9

We report improved measurements for the nu 6 antisymmetric stretch fundamental and observation of the (nu 6 + nu 15)-nu 15 and (nu 6 + 2 nu 15)-2 nu 15 hot bands of the linear C9 carbon cluster by direct absorption diode laser spectroscopy of a supersonic carbon cluster beam. Analysis of these bands characterizes C9 as a semirigid molecule with a bending potential similar to that of C5 and further evidences the alternation in degree of rigidity of linear carbon clusters with the g-u symmetry of the HOMO.