Algicidal effects on Heterosigma akashiwo and Chattonella marina (Raphidophyceae), and toxic effects on natural plankton assemblages by a thiazolidinedione derivative TD49 in a microcosm

The algicidal effects of the thiazolidinedione derivative TD49 on Heterosigma akashiwo and Chattonella marina (Raphidophyceae) were assessed, and the response of the planktonic community and environment to the algicide was evaluated in a microcosm, quantifying 12 L. The abundance of over 80 % of H. akashiwo and C. marina declined in a day significantly in microcosms to which TD49 was added (final concentration 2 μM), and this was correlated with an abrupt decline in the culture pH. The number of protists (i.e., ciliates) other than H. akashiwo and C. marina gradually increased with time in the TD49 treatments, implying that the decline in numbers of H. akashiwo and C. marina cells resulting from TD49 treatment was a major factor in the growth of the other organisms. However, TD49 may be toxic to aquatic zooplankton communities, even though it is a highly selective algicide for harmful algae bloom species. The study indicates that TD49 is an effective agent for the control for H. akashiwo and C. marina blooms in enclosed and eutrophic water bodies.     

Enhancing operational stability and exhibition of enzyme activity by removing water in the immobilized lipase‐catalyzed production of erythorbyl laurate

Erythorbyl laurate was continuously synthesized by esterification in a packed‐bed enzyme reactor with immobilized lipase from Candida antarctica. Response surface methodology based on a five‐level three‐factor central composite design was adopted to optimize conditions for the enzymatic esterification. The reaction variables, such as reaction temperature (10–70°C), substrate molar ratio ([lauric acid]/[erythorbic acid], 5–15), and residence time (8–40 min) were evaluated and their optimum conditions were found to be 56.2°C, 14.3, and 24.2 min, respectively. Under the optimum conditions, the molar conversion yield was 83.4%, which was not significantly different (P < 0.05) from the value predicted (84.4%). Especially, continuous water removal by adsorption on an ion‐exchange resin in a packed‐bed enzyme reactor improved operational stability, resulting in prolongation of half‐life (2.02 times longer compared to the control without water‐removal system). Furthermore, in the case of batch‐type reactor, it exhibited significant increase in initial velocity of molar conversion from 1.58% to 2.04%/min. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:882–889, 2013     

PKCδ as a Regulator for TGFβ1-Induced α-SMA Production in a Murine Nonalcoholic Steatohepatitis Model

The precise mechanism of TGFβ1 signaling in the progression of non-alcoholic steatohepatitis (NASH) has remained unclear. In particular, a potential regulatory mechanism by which PKCδ affects profibrogenic gene expression had never been explored. In this study, therefore, the role of PKCδ in TGFβ1 mediated α-SMA expression was investigated using NASH model mice. In preparation of the NASH model, male C57BL6/J mice were fed a methionine-choline-deficient (MCD) diet for 3 weeks, after which time they were intraperitoneally injected with lipopolysaccharide (LPS). In addition, Tlr4^Lps-d (CH3/HeJ) mice were used to demonstrate the TGFβ1 signaling’s dependency on TLR4 induction. Liver histology and hepatic hepatitis markers were investigated, and hepatic gene expression levels were determined by real-time PCR. Acute liver injury by LPS injection specifically elevated not only α-SMA expression but also phospho-PKCδ in this model. In contrast, Tlr4^Lps-d (CH3/HeJ) and blockade of TGFβ1 receptor by SB431542 resulted in a significant reduction of PKCδ activation and α-SMA expression. Moreover, the TGFβ1-induced α-SMA production was significantly reduced by a specific PKCδ inhibitor. These findings suggested that PKCδ plays a critical role in TGFβ1-induced α-SMA production in a NASH model. Thus, this was the first demonstration of the involvement of PKCδ in the regulation of α-SMA expression in NASH liver tissues, and the impaired induction of PKCδ phosphorylation by LPS in a steatohepatitis condition. Interestingly, treatment by PKCδ inhibitor caused dramatic reduction of myofibroblast activation, indicating that PKCδ represents a promising target for treating NASH.     

Two Distinct Functional Patterns of Hepatitis C Virus (HCV)-Specific T Cell Responses in Seronegative,Aviremic Patients

In hepatitis C Virus (HCV) high-risk groups, HCV-specific T cell responses have been detected in seronegative, aviremic persons who have no evidence of HCV infection. Herein, we investigated functional profiles of HCV-specific T-cell responses in seronegative, aviremic patients of a HCV high-risk group. Seventy seven hemodialysis patients with chronic renal disease were analyzed by IFN-γ ELISpot assays, and eight of 71 (11.3%) seronegative, aviremic patients displayed HCV-specific T-cell responses. Their HCV-specific memory T cells were characterized by assessing cytokine polyfunctionality, known to provide antiviral protection. By intracellular staining of IFN-γ, TNF-α, IL-2 and MIP-1β, we identified two distinct populations in the seronegative, aviremic patients: polyfunctional responders and TNF-α-predominant responders. In further analysis, occult HCV infection was excluded as a cause of the HCV-specific T cell response via secondary nested RT-PCR of HCV RNA in peripheral blood mononuclear cell samples. HCV-specific T cells targeted multiple epitopes including non-structural proteins in a single patient, implying that their T cells might have been primed by HCV proteins synthesized within the host. We conclude that HCV-specific memory T cells of seronegative, aviremic patients arise from authentic HCV replication in the host, but not from current occult HCV infection. By functional pattern of HCV-specific T cells, there are two distinct populations in these patients: polyfunctional responders and TNF-α-predominant responders.     

The Ambiguous Base-Pairing and High Substrate Efficiency of T-705 (Favipiravir) Ribofuranosyl 5′-Triphosphate towards Influenza A Virus Polymerase

T-705 (Favipiravir) is a broad-spectrum antiviral molecule currently in late stage clinical development for the treatment of influenza virus infection. Although it is believed that T-705 potency is mediated by its ribofuranosyl triphosphate (T-705 RTP) metabolite that could be mutagenic, the exact molecular interaction with the polymerase of influenza A virus (IAVpol) has not been elucidated. Here, we developed a biochemical assay to measure the kinetics of nucleotide incorporation by IAVpol in the elongation mode. In this assay, T-705 RTP was recognized by IAVpol as an efficient substrate for incorporation to the RNA both as a guanosine and an adenosine analog. Compared to natural GTP and ATP, the discrimination of T-705 RTP was about 19- and 30-fold, respectively. Although the single incorporation of the ribonucleotide monophosphate form of T-705 did not efficiently block RNA synthesis, two consecutive incorporation events prevented further primer extension. In comparison, 3′-deoxy GTP caused immediate chain termination but was incorporated less efficiently by the enzyme, with a discrimination of 4,900-fold relative to natural GTP. Collectively, these results provide the first detailed biochemical characterization to evaluate the substrate efficiency and the inhibition potency of nucleotide analogs against influenza virus polymerase. The combination of ambiguous base-pairing with low discrimination of T-705 RTP provides a mechanistic basis for the in vitro mutagenic effect of T-705 towards influenza virus.     

Trends in the Rates of Peripartum Hysterectomy and Uterine Artery Embolization

The objective of this study was to determine the trends in national rates of peripartum hysterectomy (PH) and uterine arterial embolization (UAE) in Korea. We used data collected by the Health Insurance Review & Assessment Service of Korea and analyzed data from patients who gave birth during the period from 2005 to 2008. There were 1785,178 deliveries during the study period, including 2636 cases of PH (1.48 per 1000 deliveries). The PH rate in 2005 was 1.57 per 1000 deliveries and in 2008 it was 1.33 per 1000 deliveries. UAE was performed in 161 women (incidence, 0.38 per 1000 deliveries) and 447 women (incidence, 0.98 per 1000 deliveries) in 2005 and 2008, respectively. In Korea, the rate of PH decreased slightly, while the rate of UAE rate increased dramatically during the period from 2005 to 2008. Further studies are needed to evaluate the effects of UAE on the rate of PH performed.     

Soluble ICAM-5, a Product of Activity Dependent Proteolysis,Increases mEPSC Frequency and Dendritic Expression of GluA1

Matrix metalloproteinases (MMPs) are zinc dependent endopeptidases that can be released from neurons in an activity dependent manner to play a role in varied forms of learning and memory. MMP inhibitors impair hippocampal long term potentiation (LTP), spatial memory, and behavioral correlates of drug addiction. Since MMPs are thought to influence LTP through a β₁ integrin dependent mechanism, it has been suggested that these enzymes cleave specific substrates to generate integrin binding ligands. In previously published work, we have shown that neuronal activity stimulates rapid MMP dependent shedding of intercellular adhesion molecule-5 (ICAM-5), a synaptic adhesion molecule expressed on dendrites of the telencephalon. We have also shown that the ICAM-5 ectodomain can interact with β₁ integrins to stimulate integrin dependent phosphorylation of cofilin, an event that occurs with dendritic spine maturation and LTP. In the current study, we investigate the potential for the ICAM-5 ectodomain to stimulate changes in α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor (AMPAR) dependent glutamatergic transmission. Single cell recordings show that the ICAM-5 ectodomain stimulates an increase in the frequency, but not the amplitude, of AMPA mini excitatory post synaptic currents (mEPSCs). With biotinylation and precipitation assays, we also show that the ICAM-5 ectodomain stimulates an increase in membrane levels of GluA1, but not GluA2, AMPAR subunits. In addition, we observe an ICAM-5 associated increase in GluA1 phosphorylation at serine 845. Concomitantly, ICAM-5 affects an increase in GluA1 surface staining along dendrites without affecting an increase in dendritic spine number. Together these data are consistent with the possibility that soluble ICAM-5 increases glutamatergic transmission and that post-synaptic changes, including increased phosphorylation and dendritic insertion of GluA1, could contribute. We suggest that future studies are warranted to determine whether ICAM-5 is one of a select group of synaptic CAMs whose shedding contributes to MMP dependent effects on learning and memory.     

Topical application of capsaicin reduces visceral adipose fat by affecting adipokine levels in high‐fat diet‐induced obese mice

Objective:

Visceral obesity contributes to the development of obesity‐related disorders such as diabetes, hyperlipidemia, and fatty liver disease, as well as cardiovascular diseases. In this study, we determined whether topical application of capsaicin can reduce fat accumulation in visceral adipose tissues.

Methods and Results:

We first observed that topical application of 0.075% capsaicin to male mice fed a high‐fat diet significantly reduced weight gain and visceral fat. Fat cells were markedly smaller in the mesenteric and epididymal adipose tissues of mice treated with capsaicin cream. The capsaicin treatment also lowered serum levels of fasting glucose, total cholesterol, and triglycerides. Immunoblot analysis and RT‐PCR revealed increased expression of adiponectin and other adipokines including peroxisome proliferator‐activated receptor (PPAR) α, PPARγ, visfatin, and adipsin, but reduced expression of tumor necrosis factor‐α and IL‐6.

Conclusions:

These results indicate that topical application of capsaicin to obese mice limits fat accumulation in adipose tissues and may reduce inflammation and increase insulin sensitivity.     

Selective Degradation of Host MicroRNAs by an Intergenic HCMV Noncoding RNA Accelerates Virus Production

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Effects of landscape and management on ground‐dwelling insect assemblages of farmland in Jeju Island,Korea

Granite‐derived soils are widespread in the farmland of Korea in general. In contrast, Jeju Island has mainly volcanic ash soils. Soils and weather condition in Jeju Island created a unique agricultural system. We identified the features of ground‐dwelling insects in farmlands of Jeju Island. This study was conducted in four areas (Samdal‐ri and Susan‐ri in Seogwipo city, and Dongmyeong‐ri and Suwon‐ri in Jeju city) in Jeju Island, Korea. Field surveys were carried out twice in summer (June) and autumn (September) in 2013. Ground‐dwelling insects were sampled quantitatively by using pitfall traps. As a result, in total 3322 individuals, 137 species, 48 families and 8 orders were investigated in farmlands of Jeju Island. Especially, members of Coleoptera and Hymenoptera accounted for a large proportion of ground‐dwelling insect communities. The numbers of species and individuals for major taxonomic groups showed significant regional and seasonal differences. This study implied that the seasonal and regional differences of ground‐dwelling insect communities were affected by surrounding land use patterns, life history patterns of each taxonomic group and farmland management.