Induction of heme oxygenase-1 expression in macrophages by diesel exhaust particle chemicals and quinones via the antioxidant-responsive element

Diesel exhaust particles (DEP) contain organic chemicals that contribute to the adverse health effects of inhaled particulate matter. Because DEP induce oxidative stress in the lung and in macrophages, effective antioxidant defenses are required. One type of defense is through the expression of the antioxidant enzyme, heme oxygenase I (HO-1). HO-1 as well as phase II detoxifying enzymes are induced via antioxidant response elements (ARE) in their promoters of that gene. We show that a crude DEP total extract, aromatic and polar DEP fractions, a benzo(a)pyrene quinone, and a phenolic antioxidant induce HO-1 expression in RAW264.7 cells in an ARE-dependent manner. N-acetyl cysteine and the flavonoid, luteolin, inhibited HO-1 protein expression. We also demonstrate that the same stimuli induce HO-1 mRNA expression in parallel with the activation of the SX2 enhancer of that gene. Mutation of the ARE core, but not the overlapping AP-1 binding sequence, disrupted SX2 activation. Finally, we show that biological agents, such as oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, could also induce HO-1 expression via an ARE-dependent mechanism. Prior induction of HO-1 expression, using cobalt-protoporphyrin, protected RAW264.7 cells against DEP-induced toxicity. Taken together, these data show that HO-1 plays an important role in cytoprotection against redox-active DEP chemicals, including quinones.     

NMR structure of oxidized glutaredoxin 3 from Escherichia coli

A high precision NMR structure of oxidized glutaredoxin 3 [C65Y] from Escherichia coli has been determined. The conformation of the active site including the disulphide bridge is highly similar to those in glutaredoxins from pig liver and T4 phage. A comparison with the previously determined structure of glutaredoxin 3 [C14S, C65Y] in a complex with glutathione reveals conformational changes between the free and substrate-bound form which includes the sidechain of the conserved, active site tyrosine residue. In the oxidized form this tyrosine is solvent exposed, while it adopts a less exposed conformation, stabilized by hydrogen bonds, in the mixed disulfide with glutathione. The structures further suggest that the formation of a covalent linkage between glutathione and glutaredoxin 3 is necessary in order to induce these structural changes upon binding of the glutathione peptide. This could explain the observed low affinity of glutaredoxins for S-blocked glutathione analogues, in spite of the fact that glutaredoxins are highly specific reductants of glutathione mixed disulfides.     

Effects of chronic cold exposure on the activities of cytochrome c oxidase, glutathione peroxidase and glutathione reductase in rat tissues (Rattus norvegicus)

The effects of cold acclimation on the activity levels of cytochrome c oxidase, glutathione peroxidase and glutathione reductase in various tissues of the rat (Rattus norvegicus) were investigated. One group was individually housed at 4 +/- 1 degrees C and the other at 24 +/- 1 degrees C for 6 months. Chronic cold acclimation resulted in significantly (P < 0.05) increased cytochrome c oxidase activity levels in liver, kidney, heart, interscapular brown adipose tissue and gastrocnemius muscle. The activity of glutathione peroxidase was significantly (P < 0.05) elevated in liver, interscapular brown adipose tissue, lung and muscle, whereas glutathione reductase was only significantly (P < 0.05) elevated in interscapular brown adipose tissue as a result of chronic cold exposure. The results obtained are possibly indicative of a positive compensatory response against the increased production of oxygen derived radicals as a result of chronic cold exposure.     

Vulnerability of Pathogenic Biofilms to Micavibrio aeruginosavorus

The host specificity of the gram-negative exoparasitic predatory bacterium Micavibrio aeruginosavorus was examined. M. aeruginosavorus preyed on Pseudomonas aeruginosa, as previously reported, as well as Burkholderia cepacia, Klebsiella pneumoniae, and numerous clinical isolates of these species. In a static assay, a reduction in biofilm biomass was observed as early as 3 hours after exposure to M. aeruginosavorus, and an ~100-fold reduction in biofilm cell viability was detected following a 24-h exposure to the predator. We observed that an initial titer of Micavibrio as low as 10 PFU/well or a time of exposure to the predator as short as 30 min was sufficient to reduce a P. aeruginosa biofilm. The ability of Micavibrio to reduce an existing biofilm was confirmed by scanning electron microscopy. In static and flow cell experiments, M. aeruginosavorus was able to modify the overall P. aeruginosa biofilm structure and markedly decreased the viability of P. aeruginosa. The altered biofilm structure was likely caused by an increase in cell-cell interactions brought about by the presence of the predator or active predation. We also conducted a screen to identify genes important for P. aeruginosa-Micavibrio interaction, but no candidates were isolated among the ~10,000 mutants tested.     

The first lace bug from Chiapas amber (Totolapa,Mexico) (Hemiptera: Tingidae)

Leptopharsa tacanae sp. nov., the first Tingidae from Mexican amber, is described and its morphological affinities are discussed.     

A systematic study of labelling an α-helix in a protein with a lanthanide using IDA-SH or NTA-SH tags

The previously published IDA-SH and NTA-SH tags are small synthetic lanthanide-binding tags derived from cysteine, which afford site-specific lanthanide labelling by disulfide-bond formation with a cysteine residue of the target protein. Following attachment to a single cysteine in an α-helix, sizeable pseudocontact shifts (PCS) can be observed, if the lanthanide is immobilized by additional coordination to a negatively charged amino-acid side chain that is located in a neighboring turn of the helix. To identify the best labelling strategy for PCS measurements, we performed a systematic study, where IDA-SH or NTA-SH tags were ligated to a cysteine residue in position i of an α-helix, and aspartate or glutamate residues were placed in the positions i ? 4 or i + 4. The largest anisotropy components of the magnetic susceptibility tensor were observed for an NTA-SH tag in position i with a glutamate residue in position i ? 4. While the NTA-SH tag produced sizeable PCSs regardless of the presence of nearby carboxyl groups of the protein, the IDA-SH tag generated a good lanthanide binding site only if an aspartate was placed in position i + 4. The findings provide a firm basis for the design of site-directed mutants that are suitable for the reliable generation of PCSs in proteins with paramagnetic lanthanides.     

Complete Genome and Molecular Epidemiological Data Infer the Maintenance of Rabies among Kudu (Tragelaphus strepsiceros) in Namibia

Rabies in kudu is unique to Namibia and two major peaks in the epizootic have occurred since it was first noted in 1977. Due to the large numbers of kudu that were affected, it was suspected that horizontal transmission of rabies occurs among kudu and that rabies was being maintained independently within the Namibian kudu population – separate from canid cycles, despite geographic overlap. In this study, it was our aim to show, through phylogenetic analyses, that rabies was being maintained independently within the Namibian kudu population. We also tested, through complete genome sequencing of four rabies virus isolates from jackal and kudu, whether specific mutations occurred in the virus genome due to host adaptation. We found the separate grouping of all rabies isolates from kudu to those of any other canid species in Namibia, suggesting that rabies was being maintained independently in kudu. Additionally, we noted several mutations unique to isolates from kudu, suggesting that these mutations may be due to the adaptation of rabies to a new host. In conclusion, we show clear evidence that rabies is being maintained independently in the Namibian kudu population – a unique phenomenon with ecological and economic impacts.     

Media Reporting of Neuroscience Depends on Timing,Topic and Newspaper Type

The rapid developments in neuroscientific techniques raise high expectations among the general public and therefore warrant close monitoring of the translation to the media and daily-life applications. The need of empirical research into neuroscience communication is emphasized by its susceptibility to evoke misconceptions and polarized beliefs. As the mass media are the main sources of information about (neuro-)science for a majority of the general public, the objective of the current research is to quantify how critically and accurately newspapers report on neuroscience as a function of the timing of publication (within or outside of periods of heightened media attention to neuroscience, termed “news waves”), the topic of the research (e.g. development, health, law) and the newspaper type (quality, popular, free newspapers). The results show that articles published during neuroscience news waves were less neutral and more optimistic, but not different in accuracy. Furthermore, the overall tone and accuracy of articles depended on the topic; for example, articles on development often had an optimistic tone whereas articles on law were often skeptical or balanced, and articles on health care had highest accuracy. Average accuracy was rather low, but articles in quality newspapers were relatively more accurate than in popular and free newspapers. Our results provide specific recommendations for researchers and science communicators, to improve the translation of neuroscience findings through the media: 1) Caution is warranted during periods of heightened attention (news waves), as reporting tends to be more optimistic; 2) Caution is also warranted not to follow topic-related biases in optimism (e.g., development) or skepticism (e.g., law); 3) Researchers should keep in mind that overall accuracy of reporting is low, and especially articles in popular and free newspapers provide a minimal amount of details. This indicates that researchers themselves may need to be more active in preventing misconceptions to arise.