355 research outputs found
ADAP2 Is an Interferon Stimulated Gene That Restricts RNA Virus Entry
Interferon stimulated genes (ISGs) target viruses at various stages of their infectious life cycles, including at the earliest stage of viral entry. Here we identify ArfGAP with dual pleckstrin homology (PH) domains 2 (ADAP2) as a gene upregulated by type I IFN treatment in a STAT1-dependent manner. ADAP2 functions as a GTPase-activating protein (GAP) for Arf6 and binds to phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) and PI(3,4)P2. We show that overexpression of ADAP2 suppresses dengue virus (DENV) and vesicular stomatitis virus (VSV) infection in an Arf6 GAP activity-dependent manner, while exerting no effect on coxsackievirus B (CVB) or Sendai virus (SeV) replication. We further show that ADAP2 expression induces macropinocytosis and that ADAP2 strongly associates with actin-enriched membrane ruffles and with Rab8a- and LAMP1-, but not EEA1- or Rab7-, positive vesicles. Utilizing two techniquesβlight-sensitive neutral red (NR)-containing DENV and fluorescence assays for virus internalizationβwe show that ADAP2 primarily restricts DENV infection at the stage of virion entry and/or intracellular trafficking and that incoming DENV and VSV particles associate with ADAP2 during their entry. Taken together, this study identifies ADAP2 as an ISG that exerts antiviral effects against RNA viruses by altering Arf6-mediated trafficking to disrupt viral entry
Multicriteria Decision Model for Road Construction Project
. Construction of roads plays an important role in linking one area to another, and also acts as a substance for the local economy. However, the limitation of study on the project performance towards the road infrastructure construction project requires more precise attention. Thus, it requires distinct responsiveness from contractors to evaluate and cope with the risks. This study aims to identify the project execution risk factors involved in the road construction project, reference to a current case study from a federal government project Public Work Department (PWD) on the East Coast of Malaysia: Upgrading 14.7 kilometre (km) federal road from the Pekan town to Sungai Miang. This study will begin with the identification of the project execution risk factors, utilizing an extensive review of the literature. Next, the gathered risk factors will go through a pilot phase validation interview with road construction experts from the public work department (PWD) and also construction practitioners that are involved directly in the project case study. Findings found seven (7) main project execution risk factors involved in the road construction project, which include resource risk, land acquisition issue, project management issue, technical risk, service utility issue, unforeseen ground condition, and force majeure risk. Among the seven (7) factors twenty-one (21) project execution risk sub-factors, were further explored that are crucial to the project. The main contribution of this study is the final multi-criteria decision model obtained from literature searching cross-referenced to the real case study that may be beneficial to the road construction project team specifically
Network adaptation improves temporal representation of naturalistic stimuli in drosophila eye: II Mechanisms
Retinal networks must adapt constantly to best present the ever changing visual world to the brain. Here we test the hypothesis that adaptation is a result of different mechanisms at several synaptic connections within the network. In a companion paper (Part I), we showed that adaptation in the photoreceptors (R1-R6) and large monopolar cells (LMC) of the Drosophila eye improves sensitivity to under-represented signals in seconds by enhancing both the amplitude and frequency distribution of LMCs' voltage responses to repeated naturalistic contrast series. In this paper, we show that such adaptation needs both the light-mediated conductance and feedback-mediated synaptic conductance. A faulty feedforward pathway in histamine receptor mutant flies speeds up the LMC output, mimicking extreme light adaptation. A faulty feedback pathway from L2 LMCs to photoreceptors slows down the LMC output, mimicking dark adaptation. These results underline the importance of network adaptation for efficient coding, and as a mechanism for selectively regulating the size and speed of signals in neurons. We suggest that concert action of many different mechanisms and neural connections are responsible for adaptation to visual stimuli. Further, our results demonstrate the need for detailed circuit reconstructions like that of the Drosophila lamina, to understand how networks process information
Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers
We present a review of the interplay between the evolution of circumstellar
disks and the formation of planets, both from the perspective of theoretical
models and dedicated observations. Based on this, we identify and discuss
fundamental questions concerning the formation and evolution of circumstellar
disks and planets which can be addressed in the near future with optical and
infrared long-baseline interferometers. Furthermore, the importance of
complementary observations with long-baseline (sub)millimeter interferometers
and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics
Review"; The final publication is available at http://www.springerlink.co
Influence of Various Polymorphic Variants of Cytochrome P450 Oxidoreductase (POR) on Drug Metabolic Activity of CYP3A4 and CYP2B6
Cytochrome P450 oxidoreductase (POR) is known as the sole electron donor in the metabolism of drugs by cytochrome P450 (CYP) enzymes in human. However, little is known about the effect of polymorphic variants of POR on drug metabolic activities of CYP3A4 and CYP2B6. In order to better understand the mechanism of the activity of CYPs affected by polymorphic variants of POR, six full-length mutants of POR (e.g., Y181D, A287P, K49N, A115V, S244C and G413S) were designed and then co-expressed with CYP3A4 and CYP2B6 in the baculovirus-Sf9 insect cells to determine their kinetic parameters. Surprisingly, both mutants, Y181D and A287P in POR completely inhibited the CYP3A4 activity with testosterone, while the catalytic activity of CYP2B6 with bupropion was reduced to approximately βΌ70% of wild-type activity by Y181D and A287P mutations. In addition, the mutant K49N of POR increased the CLint (Vmax/Km) of CYP3A4 up to more than 31% of wild-type, while it reduced the catalytic efficiency of CYP2B6 to 74% of wild-type. Moreover, CLint values of CYP3A4-POR (A115V, G413S) were increased up to 36% and 65% of wild-type respectively. However, there were no appreciable effects observed by the remaining two mutants of POR (i.e., A115V and G413S) on activities of CYP2B6. In conclusion, the extent to which the catalytic activities of CYP were altered did not only depend on the specific POR mutations but also on the isoforms of different CYP redox partners. Thereby, we proposed that the POR-mutant patients should be carefully monitored for the activity of CYP3A4 and CYP2B6 on the prescribed medication
Macrophage Inhibitory Cytokine 1 (MIC-1/GDF15) Decreases Food Intake, Body Weight and Improves Glucose Tolerance in Mice on Normal & Obesogenic Diets
Food intake and body weight are controlled by a variety of central and peripheral factors, but the exact mechanisms behind these processes are still not fully understood. Here we show that that macrophage inhibitory cytokine-1 (MIC-1/GDF15), known to have anorexigenic effects particularly in cancer, provides protection against the development of obesity. Both under a normal chow diet and an obesogenic diet, the transgenic overexpression of MIC-1/GDF15 in mice leads to decreased body weight and fat mass. This lean phenotype was associated with decreased spontaneous but not fasting-induced food intake, on a background of unaltered energy expenditure and reduced physical activity. Importantly, the overexpression of MIC-1/GDF15 improved glucose tolerance, both under normal and high fat-fed conditions. Altogether, this work shows that the molecule MIC-1/GDF15 might be beneficial for the treatment of obesity as well as perturbations in glucose homeostasis
Effects of Four Host Plants on Biology and Food Utilization of the Cutworm, Spodoptera litura
Effects of four host plants, tobacco, Chinese cabbage, cowpea and sweet potato, on larval and pupal development and survival, and longevity and fecundity of adults of Spodoptera litura (F) (Lepidoptera: Noctuidae), were studied under laboratory conditions (26Β° C, 60β80% RH), as was the utilization of the four host plants and adaptation on tobacco. All of the biological parameters included in the study were affected by the host plants. In a choice test, S. litura females oviposited most on Chinese cabbage, least on tobacco, and intermediate on cowpea and sweet potato. S. litura larvae developed differently on the four host plants, from shortest to longest in the following order: Chinese cabbage, cowpea, sweet potato, and tobacco. Pupal development was shorter on cowpea than on the other three host plants, and males generally developed longer than females. More females than males were found among emerged adults, and male adults lived 1β2 d longer than females. Larvae survived best on cowpea (81.6%), followed by Chinese cabbage (75.5%), then sweet potato (66.1%), and worst on tobacco (49.2%). Pupal survival rates were relatively high (91.4 β 95.9%) in all four host plant treatments, although that on sweet potato was lower than those on the other three host plants. Pupal weights on tobacco and sweet potato were similar, but both were lower than those on Chinese cabbage and cowpea. Generally, male pupae weighed less than female pupae. Numbers of eggs oviposited by female S. litura were highest on sweet potato, followed by those on cowpea, Chinese cabbage, and lowest on tobacco. Relative food consumption rate was highest on sweet potato, followed by that on cowpea, Chinese cabbage, and lowest on tobacco. In contrast, S. litura larvae that fed on tobacco had higher efficiency of conversion of digested food, highest efficiency of conversion of ingested food, and lowest approximate digestibility as compared with larvae that fed on other host plants. The potential causes for S. litura outbreaks on tobacco are discussed
The Role of Cilostazol, a Phosphodiesterase 3 Inhibitor, on Oocyte Maturation and Subsequent Pregnancy in Mice
It is important to identify effective contraceptive drugs that cause minimal disruption to physiological processes. Phosphodiesterase 3 (PDE3) inhibitors suppress meiosis in oocytes by decreasing the level of cAMP and blocking the extrusion of the first polar body. In this study, we tested the PDE3 inhibitor, cilostazol, as a potential contraceptive agent. The effects of cilostazol treatment in vitro and in vivo on the suppression of oocyte maturation in a mouse model were investigated. The results indicated that treatment with increasing concentrations of cilostazol led to a dose-dependent arrest in meiosis progression. The effective in vitro concentration was 1 Β΅M and was 300 mg/kg in vivo. The effect of cilostazol was reversible. After removal of the drug, meiosis resumed and mouse oocytes matured in vitro, and showed normal chromosome alignment and spindle organization. After fertilization using an ICSI method, the oocytes showed normal morphology, fertilization rate, embryo cleavage, blastocyst formation, and number of viable pups when compared with controls. The offspring showed similar body weight and fertility. In vivo, the mice became infertile if the drug was injected sequentially, and became pregnant following discontinuation of cilostazol. More importantly, no side effects of cilostazol were observed in treated female mice as demonstrated by blood pressure and heart rate monitoring. It is concluded that cilostazol, a drug routinely used for intermittent claudication, can effectively inhibit oocyte maturation in vitro and in vivo, does not affect the developmental potential of oocytes following drug removal and has few side effects in female mice treated with this drug. These findings suggest that cilostazol may be a potential new contraceptive agent that may facilitate an efficacy and safety study of this drug
Identification of a Functional Genetic Variant at 16q12.1 for Breast Cancer Risk: Results from the Asia Breast Cancer Consortium
Genetic factors play an important role in the etiology of breast cancer. We carried out a multi-stage genome-wide association (GWA) study in over 28,000 cases and controls recruited from 12 studies conducted in Asian and European American women to identify genetic susceptibility loci for breast cancer. After analyzing 684,457 SNPs in 2,073 cases and 2,084 controls in Chinese women, we evaluated 53 SNPs for fast-track replication in an independent set of 4,425 cases and 1,915 controls of Chinese origin. Four replicated SNPs were further investigated in an independent set of 6,173 cases and 6,340 controls from seven other studies conducted in Asian women. SNP rs4784227 was consistently associated with breast cancer risk across all studies with adjusted odds ratios (95% confidence intervals) of 1.25 (1.20β1.31) per allele (Pβ=β3.2Γ10β25) in the pooled analysis of samples from all Asian samples. This SNP was also associated with breast cancer risk among European Americans (per allele OR β=β1.19, 95% CI β=β1.09β1.31, Pβ=β1.3Γ10β4, 2,797 cases and 2,662 controls). SNP rs4784227 is located at 16q12.1, a region identified previously for breast cancer risk among Europeans. The association of this SNP with breast cancer risk remained highly statistically significant in Asians after adjusting for previously-reported SNPs in this region. In vitro experiments using both luciferase reporter and electrophoretic mobility shift assays demonstrated functional significance of this SNP. These results provide strong evidence implicating rs4784227 as a functional causal variant for breast cancer in the locus 16q12.1 and demonstrate the utility of conducting genetic association studies in populations with different genetic architectures
- β¦