Assessing the microcystins concentration through optimized protein phosphatase inhibition assay in environmental samples.

Protein phosphatase (PPase) inhibition assay (PPIA) is widely used to analyze the concentration of microcystins (MCs) because it is comparatively less expensive and faster than other assays. This study aimed to optimize the PPIA by determining a suitable reaction terminator and an optimal methanol concentration in the sample. The most suitable reaction time was 90 min, with the corresponding methanol concentration in the sample being 15% or less. When p-nitrophenyl phosphate (pNPP) was used as a substrate, copper chloride solution was suitably used as a reaction terminator, and when 4-methylumbelliferyl phosphate (MUP) was used, a glycine buffer not only increased the measurement sensitivity of the reaction product but also terminated the enzymatic reaction. When PPase 1 and MUP were used as an enzyme and a substrate, respectively, the limit of quantitation for MC-leucine/arginine (LR) was 0.02 µg/L, whereas it was 0.1 µg/L when pNPP was used as a substrate. The proposed method facilitated the measurement of MC-LR concentration without additional pretreatments, such as concentration or purification; therefore, this method was suitable and feasible for the continuous monitoring of MCs in drinking water.

Reduced left ventrolateral prefrontal cortex activation during verbal fluency tasks is associated with suicidal ideation severity in medication-naïve young adults with major depressive disorder: A functional near-infrared spectroscopy study.

The reduction in the oxygenation dynamics in the prefrontal cortex (PFC) during cognitive tasks is a well-known occurrence in major depressive disorders (MDD). Studies focusing on oxygenation changes in the PFC in individuals with suicidal ideation are limited. Therefore, this study investigated and confirmed the presence of prefrontal dysfunction depending on the intensity of suicidal ideation among 77 young adults (45 patients with MDD and 32 healthy controls) using near-infrared spectroscopy (NIRS). All participants underwent assessment with the Beck Depression Inventory-II, Beck Anxiety Inventory, and Beck Scale for Suicidal ideation. NIRS revealed relative hypofunction in the left dorsolateral PFC, left ventrolateral PFC (LVLPFC), and both orbitofrontal cortices in young adults with MDD compared to that in the healthy controls during verbal fluency tasks. Furthermore, the oxyhaemoglobin changes in the LVLPFC mediated the indirect effect of depression severity on suicidal ideation intensity. Our results confirmed that functional NIRS is a useful auxiliary tool for objectively assessing the risk of suicidal ideation.

Bactericidal effect of extracts and metabolites of Robinia pseudoacacia L. on Streptococcus mutans and Porphyromonas gingivalis causing dental plaque and periodontal inflammatory diseases.

The mouth cavity hosts many types of anaerobic bacteria, including Streptococcus mutans and Porphyromonas gingivalis, which cause periodontal inflammatory diseases and dental caries. The present study was conducted to evaluate the antibacterial potential of extracts of Robinia pseudoacacia and its different fractions, as well as some of its natural compounds against oral pathogens and a nonpathogenic reference bacteria, Escherichia coli. The antibacterial activity of the crude extract and the solvent fractions (hexane, chloroform, ethyl acetate and butanol) of R. pseudoacacia were evaluated against S. mutans, P. gingivalis and E. coli DH5α by standard micro-assay procedure using conventional sterile polystyrene microplates. The results showed that the crude extract was more active against P. gingivalis (100% growth inhibition) than against S. mutans (73% growth inhibition) at 1.8 mg/mL. The chloroform and hexane fractions were active against P. gingivalis, with 91 and 97% growth inhibition, respectively, at 0.2 mg/mL. None of seven natural compounds found in R. pseudoacacia exerted an antibacterial effect on P. gingivalis; however, fisetin and myricetin at 8 µg/mL inhibited the growth of S. mutans by 81% and 86%, respectively. The crude extract of R. pseudoacacia possesses bioactive compounds that could completely control the growth of P. gingivalis. The antibiotic activities of the hexane and chloroform fractions suggest that the active compounds are hydrophobic in nature. The results indicate the effectiveness of the plant in clinical applications for the treatment of dental plaque and periodontal inflammatory diseases and its potential use as disinfectant for various surgical and orthodontic appliances.

Perceptions of cancer risk and cause of cancer risk in korean adults.

PURPOSE: The aims of the present study were to assess the prevalence of perceived risk for cancer; to explore associations between sociodemographics and family history of cancer and perceived cancer risk; to identify perceived cause of cancer risk; and to examine the associations between sociodemographics and family history of cancer and perceived cause of cancer risk. MATERIALS AND METHODS: This cross-sectional study was conducted among 1,009 participants aged 30-69 years, selected from a population-based database in October 2009 through multiple-stratified random sampling. Information was collected about the participants' perceived cancer risk and perceived cause of cancer risk. RESULTS: Overall, 59.5% of the respondents thought they had the chance of developing cancer. Female sex, younger age, lower income, and family history of cancer were positively associated with perceived cancer risk. The most important perceived cause of cancer risk was stress. There was a difference between sociodemographics and family history of cancer and perceived cause of cancer risk. CONCLUSION: Factors affecting perceptions of cancer risk and cause of cancer risk need to be addressed in risk communications. The results provide important directions for the development of educational strategies to promote awareness and self-appraisal of cancer risk and risk factors.

Complete mitochondrial genome of the rare hypogean gobiid, Luciogobius pallidus, from Korea.

The rare hypogean gobiid, Luciogobius pallidus, inhabits mainly in groundwater, spring, or upper rocky tidal regions in Korea and Japan. In this paper, the complete mitochondrial genome sequence of L. pallidus was firstly determined. The gene composition and order of L. pallidus were similar to most of the other fishes. The total length of the rare hypogean gobiid mitochondrial genome is 16,480 bp, including 13 protein-coding genes, 22 tRNA, 2 rRNA and 1 control region (CR). All genes were encoded on the heavy (H)-strand, with the exceptions of ND6 and eight tRNA genes, as found in other vertebrates. The CR (833 bp in length) is located between the tRNA-Pro and tRNA-Phe genes and contains three central conserved sequence blocks (CSB-D, CSB-E and CSB-F), three conserved sequence blocks (CSB-1, CBS-2 and CBS-3), and its 3' end embeds a poly-T-nucleotide sequence.

Antibacterial effect of crude extract and metabolites of Phytolacca americana on pathogens responsible for periodontal inflammatory diseases and dental caries.

BACKGROUND: The oral cavity is the store house of different species of microorganisms that are continuously engaged in causing diseases in the mouth. The present study was conducted to evaluate the antibacterial potential of crude extracts of the aerial parts of Phytolacca americana and its natural compounds against two oral pathogens, Porphyromonas gingivalis and Streptococcus mutans, which are primarily responsible for periodontal inflammatory diseases and dental caries, as well as a nonpathogenic Escherichia coli. METHODS: Crude extract and fractions from the aerial parts of P. americana (0.008-1.8 mg/mL) were evaluated for their potential antibacterial activity against two oral disease causing microorganisms by micro-assays. The standard natural compounds present in P. americana, kaempferol, quercetin, quercetin 3-glucoside, isoqueritrin and ferulic acid, were also tested for their antibacterial activity against the pathogens at 1-8 µg/mL. RESULTS: The crude extract was highly active against P. gingivalis (100% growth inhibition) and moderately active against S. mutans (44% growth inhibition) at 1.8 mg/mL. The chloroform and hexane fraction controlled the growth of P. gingivalis with 91% and 92% growth inhibition at a concentration of 0.2 mg/mL, respectively. Kaempferol exerted antibacterial activity against both the pathogens, whereas quercetin showed potent growth inhibition activity against only S. mutans in a concentration dependent manner. CONCLUSION: The crude extract, chloroform fraction, and hexane fraction of P. americana possesses active natural compounds that can inhibit the growth of oral disease causing bacteria. Thus, these extracts have the potential for use in the preparation of toothpaste and other drugs related to various oral diseases.

Cognitive Enhancing and Neuroprotective Effect of the Embryo of the Nelumbo nucifera Seed.

The aim of the present study was to evaluate the effect of ENS on cognitive impairment induced by scopolamine and its potential neuroprotective effect against glutamate-induced cytotoxicity in HT22 cell and to investigate the underlying mechanisms. ENS (3, 10, 30, and 100 mg/kg), scopolamine (1 mg/kg), and donepezil (1 mg/kg) were administered to mice during a test period. Scopolamine impaired memory and learning in a water maze test and a passive avoidance test. The neuroprotective effect of ENS (10 and 100 µg/mL) was investigated on glutamate-induced cell death in HT22 cells by MTT assay. We investigated acetylcholinesterase inhibition in hippocampus and antioxidant activity, ROS levels, and Ca(2+) influx in HT22 cells to elucidate the potential mechanisms of ENS. We found that ENS significantly ameliorated scopolamine-induced memory impairment and inhibited AChE activity in hippocampus. In vitro, ENS showed potent neuroprotective effects against glutamate-induced neurotoxicity in the HT22 cell. In addition, ENS induced a decrease in ROS production and intercellular Ca(2+) accumulation and showed DPPH radical and H2O2 scavenging activity. In conclusion, ENS showed both a memory improving effect and a neuroprotective effect. Our results indicate that ENS may be of use in the treatment and prevention of neurodegenerative disorders.

Quantification of toxigenic Microcystis spp. in freshwaters by quantitative real-time PCR based on the microcystin synthetase A gene.

A method to estimate the abundance of toxigenic Microcystis in environmental samples by using quantitative real-time PCR was developed and optimized. The basis of this method is the amplification of a highly conserved region of the mcyA gene within the microcystin synthetase gene cluster. Using this method, the average copy number of mcyA gene per cell in toxigenic Microcystis strains was estimated. The molecular markers and method developed in this study can be used to monitor toxigenic strains of Microcystis in Korean freshwaters, in which harmful cyanobacterial blooms are routinely found.

Complete mitochondiral genome of the Korean red fox Vulpes vulpes (Carnivora, Canidae).

The complete mitochondrial genome sequence of Vulpes vulpes consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region (CR). CR is located between the tRNA-Pro and tRNA-Phe genes and is 1173 base pairs (bp) in length. It consists of a short non-repetitive sequence followed by 8-bp 5'-ACACACGT-3' tandem repeat between conserved sequence black I and conserved sequence black II.

Simultaneous quantification of cyanobacteria and Microcystis spp. using real-time PCR.

In order to develop a protocol to quantify cyanobacteria and Microcystis simultaneously, the primers and probe were designed from the conserved regions of 16S rRNA gene sequences of cyanobacteria and Microcystis, respectively. Probe match analysis of the Ribosomal Database Project showed that the primers matched with over 97% of cyanobacterial 16S rRNA genes, indicating these can be used to amplify cyanobacteria specifically. The TaqMan probe, which is located between two primers, matched with 98.2% of sequences in genus GpXI, in which most Microcystis strains are included. The numbers of cyanobacterial genes were estimated with the emission of SYBR Green from the amplicons with two primers, whereas those of Microcystis spp. were measured from the fluorescence of CAL Fluor Gold 540 emitted by exonuclease activity of Taq DNA polymerase in amplification. It is expected that this method enhances the accuracy and reduces the time to count cyanobacteria and potential toxigenic Microcystis spp. in aquatic environmental samples.

Complete mitochondrial genome sequence of the Korean water deer Hydropotes inermis argyropus (Cervidae, Capreolinae).

The complete mitochondrial genome sequence of Hydropotes inermis argyropus consists of 13 protein-coding, 22 tRNA, and two rRNA genes, and 1 control region (CR). Three overlaps among the 13 protein-coding genes were found: ATP8/ATP6, ND4L/ND4, and ND5/ND6. The CR was located between the tRNA-Pro and tRNA-Phe genes and is 928 bp in length. The typical conserved domains, such as TAS and CSB, were identified in the CR.

Establishment of an axenic culture of microcystin-producing Microcystis aeruginosa isolated from a Korean reservoir.

In order to establish an axenic (bacteria-free) culture of Microcystis aeruginosa NIER 10039 isolated from a Korean reservoir, the culture was subjected to sequential treatment, including ultrasonication, washing, and addition of antibiotics. Three broad-spectrum antibiotics, namely, kanamycin, ampicillin, and imipenem, were applied separately in that order. Axenicity of the culture was confirmed by cultivation on bacterial media and observation under epifluorescence and scanning electron microscopes. We are the first to establish an axenic culture of a Microcystis strain isolated from Korean reservoirs and can be used in physiological and molecular studies to control toxic Microcystis blooms.

Molecular characterization of polychlorinated biphenyl-dechlorinating populations in contaminated sediments.

Polychlorinated biphenyl (PCB)-dechlorinating microorganisms were characterized in PCB-contaminated sediments using amplified ribosomal DNA restriction analysis (ARDRA). The sediments were prepared by spiking Aroclor 1248 into PCB-free sediments, and were inoculated with microorganisms eluted from St. Lawrence River sediments. PCB-free sediments inoculated with the same inoculum served as the control. Four restriction fragment length polymorphism (RFLP) groups in the eubacterial and two in the archaeal domain were found exclusively in PCB-spiked sediment clone libraries. Sequence analysis of the four eubacterial clones showed homology to Escherichia coli, Lactosphaera pasteurii, Clostridium thermocellum, and Dehalobacter restrictus. The predominant archaeal sequence in the PCB-spiked sediment clone library was closely related to Methanosarcina barkeri, which appear to support earlier findings that methanogens are involved in PCB dechlorination. When the dot-blot hybridization was performed between the sediment DNA extract and the probes designed with eubacterial RFLP groups, the intensity of two of eubacterial RFLP groups, which showed high sequence homology to C. pascui and D. restrictus, was highly correlated with the number of dechlorinating microorganisms suggesting these two members intend to contribute to PCB dechlorination.

Effects of sulfate concentration on the anaerobic dechlorination of polychlorinated biphenyls in estuarine sediments.

In order to determine the effects of sulfate concentration on the anaerobic dechlorination of polychlorinated biphenyls, sediments spiked with Aroclor 1242 were made into slurries using media which had various sulfate concentrations ranging from 3 to 23 mM. The time course of dechlorination clearly demonstrated that dechlorination was inhibited at high concentration of sulfate due to less dechlorination of meta-substituted congeners. When the dechlorination patterns were analyzed by the calculation of Euclidean distance, the dechlorination pathway in the 3 mM sulfate samples was found to be different from that observed in the 13 mM samples, although the extent of dechlorination in these two samples was similar. It is possible that the dechlorination in the high sulfate concentration samples is inhibited by the suppression of growth of methanogen, which have been shown to be meta-dechlorinating microorganisms.