The full repertoire of Drosophila gustatory receptors for detecting an aversive compound.

The ability to detect toxic compounds in foods is essential for animal survival. However, the minimal subunit composition of gustatory receptors required for sensing aversive chemicals in Drosophila is unknown. Here we report that three gustatory receptors, GR8a, GR66a and GR98b function together in the detection of L-canavanine, a plant-derived insecticide. Ectopic co-expression of Gr8a and Gr98b in Gr66a-expressing, bitter-sensing gustatory receptor neurons (GRNs) confers responsiveness to L-canavanine. Furthermore, misexpression of all three Grs enables salt- or sweet-sensing GRNs to respond to L-canavanine. Introduction of these Grs in sweet-sensing GRNs switches L-canavanine from an aversive to an attractive compound. Co-expression of GR8a, GR66a and GR98b in Drosophila S2 cells induces an L-canavanine-activated nonselective cation conductance. We conclude that three GRs collaborate to produce a functional L-canavanine receptor. Thus, our results clarify the full set of GRs underlying the detection of a toxic tastant that drives avoidance behaviour in an insect

Common and Distinct Pathways for Cellular Activities in FGF-2 Signaling Induced by IL-1␤ in Corneal Endothelial Cells

PURPOSE. To determine the mechanism by which IL-1␤ induces FGF-2 and to elucidate the signaling pathways of IL-1␤-induced FGF-2 in corneal endothelial cells (CECs). METHODS. Expression and/or activation of FGF-2, p38, ERK1/2, and Akt was analyzed by immunoblot analysis. Cell proliferation was measured by MTT assay. Pharmacologic inhibitors were used to block PI 3-kinase, p38, or ERK1/2. RESULTS. Brief stimulation of CECs with IL-1␤ activated PI 3-kinase and p38 in a biphasic fashion. The first wave of activation, triggered by IL-1␤, involves the inductive activity of IL-1␤ on FGF-2 production; the second wave of activation, triggered by the induced FGF-2, involves the promotion of cellular activities. In both pathways, p38 acts downstream to PI 3-kinase. The inductive activity of IL-1␤ on FGF-2 is further evidenced by the conditioned medium, which contains a large amount of FGF-2. Stimulation of CECs with IL-1␤ also activated ERK1/2 in a delayed fashion. The IL-1␤-induced FGF-2 exerted cellular activities using distinct pathways: the second wave of activation of PI 3-kinase and p38 was involved in cell migration, whereas cell proliferation was simultaneously stimulated by ERK1/2 and the second wave of PI 3-kinase. Likewise, the conditioned medium demonstrated cellular activities and pathways identical with those observed in cells treated with IL-1␤. CONCLUSIONS. These data suggest that CECs produce FGF-2 by IL-1␤ stimulation through PI 3-kinase and p38. The IL-1␤-induced FGF-2 facilitates cell migration via PI 3-kinase and p38, whereas it stimulates cell proliferation using PI 3-kinase and ERK1/2 in parallel pathways. (Invest Ophthalmol Vis Sci

Information quality assessment in Korean manufacturing organization

Information quality is a complex problem. Issues relating to information quality are strongly embedded in the context of the operations of information systems. Information quality issues, therefore, have qualitative as well as quantitative underpinnings, which affect on the various dimensions of information quality. In order to improve information quality, it is essential to assess its various dimensions. This assessment provides the gaps that work as the building blocks for improving quality of information. However, assessing information quality dimensions is extremely intricate because each dimension depends upon other dimensions, which makes it difficult to objectively assess these dimensions. This research utilizes a product perspective of information and applies Six-Sigma methodology to assess information quality. It describes a case study of a Korean manufacturing organization where analytical hierarchy process and quality function deployment was utilized to determine the mutual relationships of information quality dimensions and critical to information quality factors.<br /

An Evaluation of Relative Damage to the Powertrain System in Tracked Vehicles

The objective of this study was to improve the reliability of the endurance test for the powertrain system of military tracked vehicles. The measurement system that measures the driving duty applied to the powertrain system caused by mobility on roads consists of eight analog channels and two pulse channels, including the propeller shaft output torques for the left and right sides. The data obtained from this measurement system can be used to introduce a new technology that produces the output torque of a torque converter and that can be applied to analyze the revolution counting for the endurance and road mobility in the front unit and represent the relative fatigue damages analysis technique and its results according to the driven roads through a cumulative fatigue method

Direct observation of DNA target searching and cleavage by CRISPR-Cas12a

Cas12a (also called Cpf1) is a representative type V-A CRISPR effector RNA-guided DNA endonuclease, which provides an alternative to type II CRISPR-Cas9 for genome editing. Previous studies have revealed that Cas12a has unique features distinct from Cas9, but the detailed mechanisms of target searching and DNA cleavage by Cas12a are still unclear. Here, we directly observe this entire process by using single-molecule fluorescence assays to study Cas12a from Acidaminococcus sp. (AsCas12a). We determine that AsCas12a ribonucleoproteins search for their on-target site by a one-dimensional diffusion along elongated DNA molecules and induce cleavage in the two DNA strands in a well-defined order, beginning with the non-target strand. Furthermore, the protospacer-adjacent motif (PAM) for AsCas12a makes only a limited contribution of DNA unwinding during R-loop formation and shows a negligible role in the process of DNA cleavage, in contrast to the Cas9 PAM.

Deficiency of peroxiredoxin 2 exacerbates angiotensin II-induced abdominal aortic aneurysm

Abdominal aortic aneurysm: Potential enzyme biomarker identified An enzyme with antioxidant properties may provide a biomarker and therapeutic agent to help treat abdominal aortic aneurysm (AAA). AAA involves the structural deterioration of the aorta through chronic inflammation and oxidative stress, and can trigger life-threatening artery rupture. An antioxidant enzyme called peroxiredoxin 2 (PRDX2) is increased in patients with ruptures, but whether its role in AAA is beneficial or detrimental is unclear. Goo Taeg Oh at the Ewha Womans University in Seoul, Jong-Gil Park at the Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea, and co-workers examined the effect of PRDX2 on AAA progression. PRDX2 suppressed structural damage in mice, limiting artery dilation and protein degradation. Loss of PRDX2 accelerated AAA development. Measuring levels of PRDX2 may indicate AAA severity in patients, while boosting the enzyme could repair aortic damage

Large-scale preparation of active caspase-3 in E. coli by designing its thrombin-activatable precursors

<p>Abstract</p> <p>Background</p> <p>Caspase-3, a principal apoptotic effector that cleaves the majority of cellular substrates, is an important medicinal target for the treatment of cancers and neurodegenerative diseases. Large amounts of the protein are required for drug discovery research. However, previous efforts to express the full-length caspase-3 gene in <it>E. coli </it>have been unsuccessful.</p> <p>Results</p> <p>Overproducers of thrombin-activatable full-length caspase-3 precursors were prepared by engineering the auto-activation sites of caspase-3 precursor into a sequence susceptible to thrombin hydrolysis. The engineered precursors were highly expressed as soluble proteins in <it>E. coli </it>and easily purified by affinity chromatography, to levels of 10–15 mg from 1 L of <it>E. coli </it>culture, and readily activated by thrombin digestion. Kinetic evaluation disclosed that thrombin digestion enhanced catalytic activity (<it>k</it>_cat/<it>K</it>_<it>M</it>) of the precursor proteins by two orders of magnitude.</p> <p>Conclusion</p> <p>A novel method for a large-scale preparation of active caspase-3 was developed by a strategic engineering to lack auto-activation during expression with amino acid sequences susceptible to thrombin, facilitating high-level expression in <it>E. coli</it>. The precursor protein was easily purified and activated through specific cleavage at the engineered sites by thrombin, generating active caspase-3 in high yields.</p

Moment and shear capacity of Ply-lam composed with plywood and structural timber under out-of-plane bending

The aim of this study was to investigate the moment and shear capacity of Ply-lam which is composed with plywood and structural timber. The moment and shear capacity of Ply-lam were predicted by using prediction methodologies for typical cross-laminated timber (CLT). The predicted values by the methodologies were verified by comparison with measured capacities. Fifty-eight specimens of Ply-lam (five layers) were manufactured and half of the specimens were tested for bending (span-to-depth ratio (Rsd) was 25:1). The other specimens were tested for rolling shear (Rsd)) in accordance with EN 16351. The results show that typical prediction methods for structural properties of CLT can also be used to predict those of Ply-lam, since the measured values were higher than the predicted values. In rolling shear test, 52% specimens failed by bending at the bottom layer. This indicates that the rolling shear test method in EN 16351 was not suitable for Ply-lam because the typical CLT would be reinforced by replacing the cross layer with plywood. Thus, the span-to-depth ratio needs to be reduced for hybrid CLT like Ply-lam.This project funded by Korea Forest Service (Korea Forestry Promotion Institute)