Temporal changes in the diet composition and trophic level of walleye pollock (Gadus chalcogrammus) inhabiting the middle-eastern coast of Korea.

The influences of oceanographic changes on diet composition and trophic level for pollock (Gadus chalcogrammus) inhabiting the East Sea off the Korean coast were examined based on stomach content and stable isotope analyses during 2016 and 2017. The diets of pollock consisted mainly of benthic crustaceans (particularly carid shrimps and euphausiids) and cephalopods, with a predominance of teleosts in the diets of larger individuals in deeper habitats. In 2016, amphipods, carid shrimps and cephalopods featured strongly in pollock diets, and the contribution of amphipods decreased in the diets of larger individuals and deeper depths. In 2017, euphausiids dominated at shallower depths, whereas the contributions of carid shrimps and teleosts increased in deeper habitats. Body-size-related differences in carbon stable isotope (δ13C) values were present in both 2016 and 2017, but size-related differences in nitrogen stable isotope (δ15N) values were only observed in 2017. The increased contribution of euphausiids during 2017 resulted in a distinct decrease in the trophic level of pollock compared to co-occurring higher trophic level predators, which can be linked to changes in habitat water temperature. Combined stomach contents and isotopic analyses provide a more comprehensive understanding of how fish diets and trophic levels fluctuate with changes in the type and abundance of prey resources in response to environmental changes.

Spatial and temporal variations in trophic structure of fish assemblages in the Yellow Sea revealed by C and N stable isotopes.

In this study, we assessed spatial and temporal variations in the trophic structure of fish assemblages in the Yellow Sea during spring and summer 2022 and compared their isotopic niches between the Provisional Measure Zone (PMZ) and Korea's west areas (non-PMZ) within the Yellow Sea. Spatial and temporal differences in the diversity and dominant species of fish assemblages were found between the PMZ and non-PMZ areas between the seasons. The mean δ13C values of fish assemblages were relatively higher in the non-PMZ areas than in the PMZ areas. In contrast, no significant differences were found in the mean δ15N values between the areas. Generally, the isotopic niche indices were relatively narrow in the PMZ areas compared to those in the non-PMZ areas. Overall, these spatial differences between the PMZ and non-PMZ areas suggest different trophic diversity of fish assemblages, resulting from site-specific variations in environmental conditions and community composition.

Trophic response of fishes to rainfall variability in a temperate estuarine system of Korea: A stable isotope approach.

To assess the basal resources supporting food webs impacted by rainfalls, we compared stable isotope ratios (δ13C and δ15N) of fish consumers and organic matter sources between up- and down-sites in an estuary between seasons (June and September) and years (2018 and 2019) that showed different patterns of summer monsoon. Our study showed seasonal differences in the δ13C and δ15N values of basal resources and fish consumers in both years. At the up-site, significant differences of δ13C values of fish consumers were found between years, resulting from changing rainfall period, thereby causing a shift in food availability from terrigenous organic matter to periphyton. In contrast, at the down-site, the consistent isotopic values of fishes were observed in both years, suggesting that rainfall shift has a negligible impact on resources for fishes. Overall, the annual shift in resources for fishes in the estuary may be controlled by contrasting rainfall events.

Development of a Quantitative PCR Assay for Four Salmon Species Inhabiting the Yangyangnamdae River Using Environmental DNA.

A species-specific quantitative PCR (qPCR) assay using environmental DNA (eDNA) is a promising tool for both qualitative and quantitative analyses of target species directly from water samples. Despite its reliability, an eDNA-based qPCR assay pipeline has not yet developed to monitor salmon species inhabiting Korean waters, which have been rapidly decreasing. We designed species-specific primers for four Oncorhynchus species inhabiting the eastern coastal waters along the Korean Peninsula. These include primers for two native species (Oncorhynchus keta and O. masou) and two that were introduced (O. mykiss and O. kisutch). The limit of detection and limit of quantification for the four qPCR assays ranged from 4.11 to 10.38 copies and from 30 to 81 copies, respectively, indicating a high sensitivity and specificity across all four species. Following optimization, the qPCR assays were used for the quantitative analyses of the four Oncorhynchus species in the Yangyangnamdae River during the spawning and non-spawning seasons in the year 2019-2020, one of the main rivers where salmon migrate during the spawning season in Korea. The raw copy numbers in all of the examined samples were normalized by PCR inhibition rates to standardize and compare with other studies. Among the four Oncorhynchus species examined, the eDNA concentration of O. keta increased significantly (63.60-fold, p < 0.0001) during the spawning season (November) compared with that in the non-spawning season (March), suggesting that O. keta is the main salmon species migrating through the Yangyangnamdae River. In contrast, we did not detect any differences in eDNA concentration for the other three Oncorhynchus species between the spawning and non-spawning seasons, indicating that their presence does not alter during the year. Their eDNA concentration is also relatively low compared to O. keta, which suggests that small numbers of these three species are present in the river. Overall, these newly developed qPCR assays represent useful monitoring tools for the management of four salmon species in Korean waters.

Shifting resource utilization of the lacustrine shrimp Palaemon paucidens in temperate coastal lagoons of Korea as revealed by stable isotopes.

The spatial and seasonal variations in resource use of the lacustrine shrimp Palaemon paucidens were investigated in three different Korean lagoon systems in June and October 2018 by measuring their carbon and nitrogen stable isotope ratios. P. paucidens had much higher δ13C values at the permanently open lagoon (PL) as compared to the intermittently open lagoons (ILs), revealing a disparity in resource utilization. Isotopic niches of the shrimp were relatively wider at the PL than at the ILs, suggesting a greater diversity of carbon pathways in the PL system. These results indicate that the degree of water exchange with the sea, associated with lagoon geomorphology, may be a major factor influencing resource availability for P. paucidens. Our findings suggest that the duration and degree of inlet opening may affect dietary variation at the population level, and may be one of the key components of sustainable management for coastal lagoon ecosystems.

Development of the cephalopod-specific universal primer set and its application for the metabarcoding analysis of planktonic cephalopods in Korean waters.

Although spatiotemporal analysis of the cephalopod larvae provides the useful information for the effective management of their resources, it has been difficult mainly due to their low numbers in the mixed zooplankton net samples and difficulty in morphological identification. In order to analyze the planktonic cephalopods using next-generation sequencing (NGS), we have designed a cephalopod-specific universal (CPD) primer set targeting a region covering mitochondrial cytochrome b and ND6 genes based on the currently identified 36 complete cephalopod mitochondrial genome sequences in the GenBank database. The expected amplicon sizes by CPD primers were between 465 and 471 bp, which was applicable to the MiSeq system (Illumina, San Diego, CA, USA). NGS results of pooled DNAs from 8 months (including 739 zooplankton net samples) collected from Korean waters in 2016 showed the exclusive cephalopod sequences with little contaminant sequences supporting the specificity of CPD primer set. Total 47 representative cephalopod haplotypes (seven families and 10 genera) were obtained from 1,439,414 merged reads. Among the total analyzed haplotypes, Watasenia scintillans, Todarodes pacificus, and Sepiola birostrata were the most abundant species in Korean waters. Two "unidentified" clades in order Oegopsida were identified, which was showed less than 90% sequence identity but closely related to Enoploteuthidae and Idiosepiidae, respectively. Monthly changes in proportions of each haplotype were also identified, which may reflect its reproduction and spawning period. The larvae of W. scintillans was dominant from February to June, while high proportions of other cephalopod taxa were also identified from August to November. Only single haplotype was dominant in W. scintillans (Type 2) throughout the year, while two distinct haplotypes showed seasonal differences in T. pacificus.

Concentrations and Risk Assessment of Heavy Metals in Tissues of Walleye Pollock (Gadus chalcogrammus) Captured from the Northeastern Coast of Korea.

HIGHLIGHTS: All heavy metals, except Hg, were well accumulated in liver compared with muscle and gonads. Estimated daily intakes of heavy metals were within 2% of the provisional maximum tolerable daily intakes, Hazard quotients of heavy metals were less than 1.0. Appropriate intake control of G. chalcogrammus is necessary to protect human health in the future.

Characterization of complete mitochondrial genome of two-spot swimming crab Charybdis bimaculata (Miers, 1886).

The two-spot swimming crab Charybdis bimaculata (Miers, 1886) is an important decapod species in the benthic ecosystem of Korean waters. In this study, we determined its complete mitochondrial genome by the combination of NGS analysis using MiSeq platform and PCR-based cloning method. The circular mitochondrial genome of C. bimaculata was 15,714 bp in length in which the standard set of 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes were encoded. Phylogenic analysis showed that C.bimaculata is most closely related to Charybdis feriata. The complete mitogenome sequence information of C. bimaculata would provide useful data for the conservation of their population in the Pacific ocean.

Molecular characterization of an adiponectin receptor homolog in the white leg shrimp, Litopenaeus vannamei.

Adiponectin (AdipoQ) and its receptors (AdipoRs) are strongly related to growth and development of skeletal muscle, as well as glucose and lipid metabolism in vertebrates. Herein we report the identification of the first full-length cDNA encoding an AdipoR homolog (Liv-AdipoR) from the decapod crustacean Litopenaeus vannamei using a combination of next generation sequencing (NGS) technology and bioinformatics analysis. The full-length Liv-AdipoR (1,245 bp) encoded a protein that exhibited the canonical seven transmembrane domains (7TMs) and the inversed topology that characterize members of the progestin and adipoQ receptor (PAQR) family. Based on the obtained sequence information, only a single orthologous AdipoR gene appears to exist in arthropods, whereas two paralogs, AdipoR1 and AdipoR2, have evolved in vertebrates. Transcriptional analysis suggested that the single Liv-AdipoR gene appears to serve the functions of two mammalian AdipoRs. At 72 h after injection of 50 pmol Liv-AdipoR dsRNA (340 bp) into L. vannamei thoracic muscle and deep abdominal muscle, transcription levels of Liv-AdipoR decreased by 93% and 97%, respectively. This confirmed optimal conditions for RNAi of Liv-AdipoR. Knockdown of Liv-AdipoR resulted in significant changes in the plasma levels of ammonia, 3-methylhistine, and ornithine, but not plasma glucose, suggesting that that Liv-AdipoR is important for maintaining muscle fibers. The chronic effect of Liv-AdipoR dsRNA injection was increased mortality. Transcriptomic analysis showed that 804 contigs were upregulated and 212 contigs were downregulated by the knockdown of Liv-AdipoR in deep abdominal muscle. The significantly upregulated genes were categorized as four main functional groups: RNA-editing and transcriptional regulators, molecular chaperones, metabolic regulators, and channel proteins.

Caffeine induces behavioural sensitization and overexpression of cocaine-regulated and amphetamine-regulated transcript peptides in mice.

This study examined whether repeated administration of caffeine would induce behavioural sensitization and overexpression of cocaine-regulated and amphetamine-regulated transcript (CART) peptides in mice. The involvement of dopaminergic receptors and adenosine receptors in caffeine-induced behavioural sensitization and CART overexpression was studied. The relevance of D1R and D2R, and A1R and A(2A)R in the overexpression of CART peptides in mouse striatum was also evaluated. Repeated administration of caffeine induced behavioural sensitization in mice. Significant increases in CART mRNA levels were observed on day 3 and peaked at day 5 of caffeine administration, and then decreased gradually. Higher proportions of CART⁺ cells were observed in the dorsolateral and ventrolateral part of the caudate putamen than in the nucleus accumbens shell and core. The behavioural sensitization induced by caffeine was inhibited by dopaminergic receptor antagonists and adenosine receptor agonists. D1R and D2R, and cyclic AMP (cAMP)/protein kinase A (PKA)/phospho-cAMP response element-binding protein (pCREB) signalling were activated by caffeine, but A1R and A(2A)R were inhibited. Overexpression of caffeine-induced CART peptides and pCREB activity were blocked by N-cyclopentyladenosine (CPA, an A1R agonist) and 4-[2-[[6-amino-9-(N-ethyl-ß-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS 21680, an A(2A)R agonist), but not by R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH 23390, a D1R antagonist) or raclopride (a D2R antagonist). Caffeine-induced overexpression of CART peptides was associated with the inhibition of A1R and A(2A)R, and the activation of cAMP/PKA/pCREB signalling. Moreover, the A(2A)R-D2R heterodimer might be involved in the overexpression of CART peptides induced by caffeine.

3,4,5-Trimethoxycinnamic acid (TMCA), one of the constituents of Polygalae Radix enhances pentobarbital-induced sleeping behaviors via GABAAergic systems in mice.

These experiments were performed to investigate whether 3,4,5-trimethoxycinnamic acid (TMCA), one of the constituents derived from Polygalae Radix, enhances pentobarbital-induced sleeping behaviors, and to alter sleep architecture through the γ-aminobutyric acid (GABA)ergic systems in mice. TMCA decreased the locomotor activity. TMCA prolonged total sleep time, and reduced sleep latency induced by pentobarbital, similar to muscimol, a GABAA agonist. From the electrocencephalogram recording for 6 h after TMCA administration, the number of sleep/wake cycles were reduced by TMCA. TMCA also increased the total sleep time and non-rapid eye movement (NREM) sleep. In addition, TMCA increased Cl(-) influx in primary cultured cerebellar granule cells of mice. TMCA increased the activation of glutamic acid decarboxylase (GAD) and the expressions of γ-subunit of GABAA receptors in the cerebellar granule cells. However, α- and ß-subunits proteins of GABAA receptors were not increased. Therefore, TMCA would increase pentobarbital induced-sleep and NREM sleep in mice. These results indicate that TMCA may enhance sleep and alter sleep architecture through GABAAergic systyems.

Cordycepin Increases Nonrapid Eye Movement Sleep via Adenosine Receptors in Rats.

Cordycepin (3'-deoxyadenosine) is a naturally occurring adenosine analogue and one of the bioactive constituents isolated from Cordyceps militaris/Cordyceps sinensis, species of the fungal genus Cordyceps. It has traditionally been a prized Chinese folk medicine for the human well-being. Because of similarity of chemical structure of adenosine, cordycepin has been focused on the diverse effects of the central nervous systems (CNSs), like sleep regulation. Therefore, this study was undertaken to know whether cordycepin increases the natural sleep in rats, and its effect is mediated by adenosine receptors (ARs). Sleep was recorded using electroencephalogram (EEG) for 4 hours after oral administration of cordycepin in rats. Sleep architecture and EEG power spectra were analyzed. Cordycepin reduced sleep-wake cycles and increased nonrapid eye movement (NREM) sleep. Interestingly, cordycepin increased θ (theta) waves power density during NREM sleep. In addition, the protein levels of AR subtypes (A1, A2A, and A2B) were increased after the administration of cordycepin, especially in the rat hypothalamus which plays an important role in sleep regulation. Therefore, we suggest that cordycepin increases theta waves power density during NREM sleep via nonspecific AR in rats. In addition, this experiment can provide basic evidence that cordycepin may be helpful for sleep-disturbed subjects.

ESM-1 regulates cell growth and metastatic process through activation of NF-κB in colorectal cancer.

In our previous study, we reported that endothelial cell specific molecule-1 (ESM-1) was increased in tissue and serum from colorectal cancer patients and suggested that ESM-1 can be used as a potential serum marker for early detection of colorectal cancer. The aim of this study was to evaluate the role of ESM-1 as an intracellular molecule in colorectal cancer. ESM-1 expression was knocked down by small interfering RNA (siRNA) in colorectal cancer cells. Expression of ESM-1 siRNA decreased cell survival through the Akt-dependent inhibition of NF-κB/IκB pathway and an interconnected reduction in phospho-Akt, -p38, -ERK1, -RSK1, -GSK-3α/ß and -HSP27, as determined by a phospho-MAPK array. ESM-1 silencing induced G(1) phase cell cycle arrest by induction of PTEN, resulting in the inhibition of cyclin D1 and inhibited cell migration and invasion of COLO205 cells. Consistently, ESM-1 overexpression in HCT-116 cells enhanced cell proliferation through the Akt-dependent activation of NF-κB pathway. In addition, ESM-1 interacted with NF-κB and activated NF-κB promoter. This study demonstrates that ESM-1 is involved in cell survival, cell cycle progression, migration, invasion and EMT during tumor invasion in colorectal cancer. Based on our results, ESM-1 may be a useful therapeutic target for colorectal cancer.

Dysregulation of overexpressed IL-32α in hepatocellular carcinoma suppresses cell growth and induces apoptosis through inactivation of NF-κB and Bcl-2.

IL-32 is a newly discovered cytokine. Recently, various reports suggest that it plays a role as a proinflammatory mediator and may be involved in several cancer carcinogenesis. However, IL-32 expression in hepatocellular carcinoma (HCC) remains unclear. In this study, we investigated the expression and role of IL-32α in hepatocellular carcinoma, because IL-32 was identified as an upregulated gene in hepatocellular carcinoma tissues compared to nontumorous regions using DNA microarray. IL-32α was overexpressed in tissue and serum from patients with HCC and localized in the cytoplasm and nucleus of hepatocellular carcinoma tumor cells. Moreover, secreted IL-32α concentration in the serum of patients with hepatocellular carcinoma was elevated as compared with those in the normal serum using a developed sandwich ELISA. Furthermore, IL-32α suppression in hepatocellular carcinoma decreased expression of phospho-p38 MAPK, NF-κB, and antiapoptotic protein Bcl-2 and induced expression of proapoptotic proteins as well as p53 and PUMA resulting in the suppression of cell growth and induction of intrinsic apoptosis. Based on our results, we suggest that IL-32α is involved in the progression of hepatocellular carcinoma and may be a useful biomarker for diagnosis and therapeutic target of hepatocellular carcinoma.

Repeated Administration of Korea Red Ginseng Extract Increases Non-Rapid Eye Movement Sleep via GABAAergic Systems.

The current inquiry was conducted to assess the change in sleep architecture after long periods of administration to determine whether ginseng can be used in the therapy of sleeplessness. Following post-surgical recovery, red ginseng extract (RGE, 200 mg/ kg) was orally administrated to rats for 9 d. Data were gathered on the 1st, 5th, and 9th day, and an electroencephalogram was recorded 24 h after RGE administration. Polygraphic signs of unobstructed sleep-wake activities were simultaneously recorded with sleep-wake recording electrodes from 11:00 a.m. to 5:00 p.m. for 6 h. Rodents were generally tamed to freely moving polygraphic recording conditions. Although the 1st and 5th day of RGE treatment showed no effect on power densities in non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, the 9th day of RGE administration showed augmented α-wave (8.0 to 13.0 Hz) power densities in NREM and REM sleep. RGE increased total sleep and NREM sleep. The total percentage of wakefulness was only decreased on the 9th day, and the number of sleep-wake cycles was reduced after the repeated administration of RGE. Thus, the repeated administration of RGE increased NREM sleep in rats. The α-wave activities in the cortical electroencephalograms were increased in sleep architecture by RGE. Moreover, the levels of both α- and ß-subunits of the γ-aminobutyric acid (GABA)A receptor were reduced in the hypothalamus of the RGE-treated groups. The level of glutamic acid decarboxylase was over-expressed in the hypothalamus. These results demonstrate that RGE increases NREM sleep via GABAAergic systems.

ESM-1 silencing decreased cell survival, migration, and invasion and modulated cell cycle progression in hepatocellular carcinoma.

Endothelial cell-specific molecule-1 (ESM-1) is a secretory proteoglycan comprising a mature polypeptide of 165 amino acids and a single dermatan sulfate. The aim of this study was to evaluate endothelial cell-specific molecule-1 (ESM-1) as a hepatocellular carcinoma (HCC) marker and to analyze the effect of ESM-1 gene silencing in hepatocellular carcinoma cells. RT-PCR and Western Blot analysis revealed overexpression of ESM-1 in human HCC liver tissue and in serum from patients with HCC. Sandwich ELISA assay was used for quantitative analysis of ESM-1 in serum. Levels of ESM-1 were significantly elevated in the serum of patients with HCC (n = 40) as compared to serum from patients with hepatitis (AH, n = 40; CH, n = 39) or liver cirrhosis (n = 40) or from healthy subjects (n = 40). The accuracy of ESM-1 for HCC was higher than that of α-fetoprotein (AFP) according to ROC curve analysis. Expression of ESM-1 siRNA decreased cell survival through the inhibition of NF-κB pathway and induced cell cycle arrest by PTEN induction resulting in the inhibition of cyclin D1 in SK-Hep1 cells. Furthermore, ESM-1 silencing inhibited cell migration and invasion of SK-Hep1 cells. This study demonstrates that ESM-1 as a potential tumor marker is overexpressed in most tissues and serum in the presence of HCC and is involved with cell survival, cell cycle progression, migration, and invasion of hepatocellular carcinoma cells. Based on our results, we suggest that ESM-1 or a combination of ESM-1 and AFP is useful markers for diagnosis of HCC and ESM-1 may be useful therapeutic target of hepatocellular carcinoma.

Development of a fluorescent microsphere immunoassay for cystatin B (CSTB) in serum of patients with hepatocellular carcinoma.

BACKGROUND: Serum cystatin B (CSTB) concentrations have been reported to be increased in patients with hepatocellular carcinoma compared to concentrations seen in normal subjects. In this study, we developed a "fluorescent microsphere immunoassay" (FMI) capable of specifically detecting CSTB in serum. METHODS: The FMI used a microparticle conjugated polyclonal antibody to CSTB and biotinylated monoclonal antibody as capture protein and probe protein, respectively. The results were obtained using the Bio-Plex(200) system. RESULTS: The dose-response relationship between CSTB and fluorescent intensity showed linearity in the range 0-1000 pg/mL and 7 pg/mL, sensitivity lower than 11.2 pg/mL. This result revealed that the FMI system was more sensitive than enzyme-linked immunoassay (ELISA). Additionally, the FMI system used smaller sample volumes compared to ELISA. CONCLUSIONS: We measured CSTB with both the FMI and an ELISA procedure and compared the two methods. The CSTB concentrations in serum specimens as measured with the FMI assay system were similar to those measured with ELISA. Thus, the new FMI using the Bio-Plex system may be useful for detection of CSTB in human serum.

Identification of endothelial cell-specific molecule-1 as a potential serum marker for colorectal cancer.

No ideal serum markers for screening colorectal cancer (CRC) have been identified. The aim of this study was to determine the usefulness of endothelial cell-specific molecule-1 (ESM-1) as a serum marker for CRC. Illumina microarray was carried out to search CRC-related biomarkers. cDNA microarray detected that ESM-1 was one of the overexpressed genes in CRC. Overexpression of ESM-1 mRNA was confirmed in tissues of CRC by RT-PCR and real-time PCR. Immunohistochemical staining showed strong expression of ESM-1 in the cytoplasm of tumor cells. Overexpression of ESM-1 in human serum with CRC was found by Western blot analysis. For quantitative analysis of ESM-1 in serum, we determined the ESM-1 levels in serum specimens using an ELISA kit. We showed that the ESM-1 levels in the serum of patients with CRC were significantly elevated (70.1 ± 29.7 pg/mL) compared to healthy subjects (29.7 ± 14.9 pg/mL). The accuracy, sensitivity, and specificity of ESM-1 for CRC were 0.94, 99%, and 73%, respectively, by receiver operating characteristics curve analysis. The positive predictive value and negative predictive value were 63% and 95%, respectively. The likelihood ratios of a positive or negative test result were 73 and 0.27, respectively. When analyzed with a Cox regression model, a higher serum ESM-1 level (≥76.0 pg/mL) was correlated with poor prognosis. This study suggests that expression of ESM-1 is increased in tissue and serum of CRC patients and that ESM-1 can be used as a potential serum marker for the early detection of CRC.

Evaluation of annexin II as a potential serum marker for hepatocellular carcinoma using a developed sandwich ELISA method.

Annexin II (Annexin A2, ANXA2) is a 36 kDa calcium-dependent phospholipid-binding protein that is located on the surface of most eukaryotic cells. ANXA2 is involved in several biological processes, including anti-inflammatory effects, Ca27+-dependent exocytosis, immune responses, Ca2+ transport and phospholipase A2 regulation. In our previous study, ANXA2 was identified as an up-regulated gene in hepatocellular carcinoma (HCC) tissue by cDNA microarray. In the present study, we have evaluated ANXA2 as a tumor-associated marker of HCC. We determined the ANXA2 levels in human liver tissues with HCC using real-time RT-PCR and Western blot analysis. For quantitative analysis of the ANXA2 protein in body fluids, we developed a sandwich ELISA system in which a polyclonal antibody and a monoclonal antibody specific to ANXA2 were employed as a capture antibody and a probe antibody, respectively. We detected the ANXA2 concentration in human serum using our newly developed system and evaluated its usefulness as a tumor marker. Overexpression of ANXA2 in human liver tissue was confirmed by real-time RT-PCR and Western blot analysis. The sandwich ELISA system for ANXA2 was developed for the detection of ANXA2 in human samples. The dose-response relationship between ANXA2 and optical density was linear in the range of 0-10 microg/ml and the sensitivity was 0.02 microg/ml. We determined the ANXA2 concentration in serum specimens using the newly developed sandwich ELISA. The serum ANXA2 concentrations of the patients with HCC (53.38+/-36.23 microg/ml) were significantly elevated when compared with those of normal individuals (28.81+/-24.94 microg/ml). These results suggest that expression of ANXA2 may be increased in HCC patients and may play an important role in liver cancer progression. This new ELISA method can be used as a tool for the detection of ANXA2 in human serum, particularly for cancer diagnostics.

A micro-thermoelectric gas sensor for detection of hydrogen and atomic oxygen.

This paper demonstrates the fabrication and performance of a micro-thermoelectric gas sensor for an effective and inexpensive gas analysis system. The proposed micro-thermoelectric gas sensor was fabricated by using a surface micromachining technique. The sensing mechanism, consisting of thermoelectric material and a novel metal catalyst, was fabricated on the highly thermally resistive layer for reduced heat transfer to the substrate allowing for a simple fabrication process. The micro-thermoelectric gas sensor detects target gas species by measuring the reaction heat of the catalytic reaction between the target gas and a novel metal catalyst using Cu-Bi thermopiles. The catalytic reaction occurs only on the hot junction of the sensing thermopile where the metal catalyst is deposited. In order to reduce the external thermal noise, a difference between the output voltage of the sensing and the reference thermopiles was measured by using a differential amplifier. The response of the fabricated sensor was linear to temperature difference. The fabricated sensor can be used to detect various concentrations of hydrogen and atomic oxygen, where the output voltage linearly increased with the gas concentration.