Destruxin E Decreases Beta-Amyloid Generation by Reducing Colocalization of Beta-Amyloid-Cleaving Enzyme 1 and Beta-Amyloid Protein Precursor

Alzheimer-disease-associated beta-amyloid (A beta) is produced by sequential endoproteolysis of beta-amyloid protein precursor (beta APP): the extracellular portion is shed by cleavage in the juxtamembrane region by beta-amyloid-cleaving enzyme (BACE)/beta-secretase, after which it is cleaved by presenilin (PS)/gamma-secretase near the middle of the transmembrane domain. Thus, inhibition of either of the secretases reduces A beta generation and is a fundamental strategy for the development of drugs to prevent Alzheimer disease. However, it is not clear how small compounds reduce A beta production without inhibition of the secretases. Such compounds are expected to avoid some of the side effects of secretase inhibitors. Here, we report that destruxin E (Dx-E), a natural cyclic hexadepsipeptide, reduces A beta generation without affecting BACE or PS/gamma-secretase activity. In agreement with this, Dx-E did not inhibit Notch signaling. We found that Dx-E decreases colocalization of BACE1 and beta APP, which reduces beta-cleavage of beta APP. Therefore, the data demonstrate that Dx-E represents a novel A beta-reducing process which could have fewer side effects than secretase inhibitors. Copyright (C) 2009 S. Karger AG, Base

The effect of pioneer carrion beetles on the emission of volatile organic compounds and carrion insect community assembly

Abstract Mechanisms of carrion insect succession have been interpreted separately from interspecific interactions between early and later colonists or from changes in volatile organic compounds perceived by insects resulting from the progression of decomposition. To link these perspectives, we examined through laboratory and field experiments whether the modification of volatile organic compounds by early colonists could be a mechanism of succession. In the laboratory experiment, we used Necrophila japonica (Coleoptera, Staphylinidae) as an early colonist and examined its effects on the emissions of important volatile attractants for carrion insects, dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) from carcasses. We collected DMDS and DMTS, using the static headspace method, under the following conditions: (i) rat carcass, (ii) rat carcass with artificial damage to the abdomen, (iii) rat carcass fed on by 10 Ne. japonica individuals, and (iv) 10 Ne. japonica individuals, and analyzed the collected gases using a gas chromatograph‐mass spectrometer. After 12 and 30 h, carcasses fed on by Ne. japonica emitted higher concentrations of DMDS and DMTS than in other conditions. In the field experiment, we examined the effects of DMDS and DMTS on the attraction of carrion insects using traps baited with a mixture of DMDS and DMTS, hexane (odors unrelated to carcasses), or an empty microtube. Traps baited with DMDS and DMTS attracted more necrophagous species and individuals than traps not baited with this combination. These results showed that accelerated emissions of DMDS and DMTS from carcasses caused by early colonists may contribute to community assembly during carrion insect succession

Polycyclic Aromatic Hydrocarbons in Sediments and Bivalves on the Pacific Coast of Japan: Influence of Tsunami and Fire.

Surface sediments and at least one edible bivalve species (Ruditapes philippinarum, Mytilus galloprovincialis, and Crassostrea gigas) were collected from each of seven intertidal sites in Japan in 2013. The sites had experienced varying levels of tsunami and fire disturbance following the major earthquake of 2011. Eight polycyclic aromatic hydrocarbons (PAHs) were identified and analyzed by gas chromatography-mass spectrometry. Total sediment PAH concentration (CT), the sum of the average concentrations of the eight PAHs, was 21-1447 μg kg-1-dry. Relative to the average level of one type of PAH in sediments collected around Japan in 2002 (benzo[a]pyrene = 21 μg kg-1-dry), five of the seven sites showed concentrations significantly lower than this average in 2013. The CTs for the three bivalves (134-450 μg kg-1-dry) were within the range of the previous reports (2.2-5335 μg kg-1-dry). The data suggest that the natural disaster did not increase PAH concentrations or affect the distribution within sediment or bivalves in Tohoku district. Although PAH concentrations at the sites pose no risk to human health, the findings highlight that the observed PAH levels derive from pre- rather than post-quake processes

Data from "The effect of pioneer<b> </b>carrion beetles on the emission of volatile organic compounds and carrion insect community assembly"

Raw data and R script for Statistical analyses in the paper "The effect of pioneer carrion beetles on the emission of volatile organic compounds and carrion insect community assembly" by Ito et al. (2023) Ecology and Evolution.</p

Description of sediment sampling sites.

<p>Description of sediment sampling sites.</p

Average concentrations (μg kg^-1-dry) of PAHs in bivalves (<i>n</i> = 3).

<p>Average concentrations (μg kg^-1-dry) of PAHs in bivalves (<i>n</i> = 3).</p

Average concentrations (μg kg^-1-dry) of PAHs in sediments (<i>n</i> = 3) versus sediment quality assessment guidelines.

<p>Average concentrations (μg kg^-1-dry) of PAHs in sediments (<i>n</i> = 3) versus sediment quality assessment guidelines.</p

Details of bivalve samples collected for analysis.

<p>Details of bivalve samples collected for analysis.</p

Total PAH concentrations in bivalves worldwide.

<p>Total PAH concentrations in bivalves worldwide.</p

Photograph of the Tona coast at high tide on 5 April 2011.

<p>(25 days after the tsunami, showing many submerged cars).</p