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1.
Andrew J. Wright Marie Maar Christian Mohn Jacob Nabe-Nielsen Ursula Siebert Lasse Fast Jensen Hans J. Baag?e Jonas Teilmann 《PloS one》2013,8(2)
An unprecedented 85 harbour porpoises stranded freshly dead along approximately 100 km of Danish coastline from 7–15 April, 2005. This total is considerably above the mean weekly stranding rate for the whole of Denmark, both for any time of year, 1.23 animals/week (ranging from 0 to 20 during 2003–2008, excluding April 2005), and specifically in April, 0.65 animals/week (0 to 4, same period). Bycatch was established as the cause of death for most of the individuals through typical indications of fisheries interactions, including net markings in the skin and around the flippers, and loss of tail flukes. Local fishermen confirmed unusually large porpoise bycatch in nets set for lumpfish (Cyclopterus lumpus) and the strandings were attributed to an early lumpfish season. However, lumpfish catches for 2005 were not unusual in terms of season onset, peak or total catch, when compared to 2003–2008. Consequently, human activity was combined with environmental factors and the variation in Danish fisheries landings (determined through a principal component analysis) in a two-part statistical model to assess the correlation of these factors with both the presence of fresh strandings and the numbers of strandings on the Danish west coast. The final statistical model (which was forward selected using Akaike information criterion; AIC) indicated that naval presence is correlated with higher rates of porpoise strandings, particularly in combination with certain fisheries, although it is not correlated with the actual presence of strandings. Military vessels from various countries were confirmed in the area from the 7th April, en route to the largest naval exercise in Danish waters to date (Loyal Mariner 2005, 11–28 April). Although sonar usage cannot be confirmed, it is likely that ships were testing various equipment prior to the main exercise. Thus naval activity cannot be ruled out as a possible contributing factor. 相似文献
2.
Pei W. Thomas Timothy Spicer Michael Cammarata Jennifer S. Brodbelt Peter Hodder Walter Fast 《Bioorganic & medicinal chemistry》2013,21(11):3138-3146
Due to the global threat of antibiotic resistance mediated by New Delhi metallo-beta-lactamase-1 (NDM-1) and the lack of structurally diverse inhibitors reported for this enzyme, we developed screening and counter-screening assays for manual and automated formats. The manual assay is a trans-well absorbance-based endpoint assay in 96-well plates and has a Z′ factor of 0.8. The automated assay is an epi-absorbance endpoint assay in 384-well plates, has a Z′ factor of ?0.8, good signal/baseline ratios (>3.8), and is likely scalable for high-throughput screening (HTS). A TEM-1-based counter-screen is also presented to eliminate false positives due to assay interference or off-target activities. A pilot screen of a pharmacologically characterized compound library identified two thiol-modifying compounds as authentic NDM-1 inhibitors: p-chloromecuribenzoate (p-CMB) and nitroprusside. Recombinant NDM-1 has one Cys residue that serves as a conserved active-site primary zinc ligand and is selectively modified by p-CMB as confirmed by LC–MS/MS. However a C208D mutation results in an enzyme that maintains almost full lactamase activity, yet is completely resistant to the inhibitor. These results predict that covalent targeting of the conserved active-site Cys residue may have drawbacks as a drug design strategy. 相似文献
3.
Occurrence of two serologically distinct groups within Bacillus thuringiensis serotype 3 ab var. kurstaki 总被引:7,自引:0,他引:7
Two groups distinguishable on the basis of crystal serology have been identified within Bacillus thuringiensis var kurstaki (serotype 3 ab). The toxicities of these two groups to Trichoplusia ni and Heliothis virescens expressed as ratio also differed. It is suggested that serotype 3 ab be separated into two subgroups designated as K-1 and K-73. 相似文献
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6.
Paul S Marley Aboubacar Toure Jay Shebayan DA Aba AO Toure AG Diallo 《Archives Of Phytopathology And Plant Protection》2013,46(1):29-34
Fourteen elite sorghum lines were evaluated for their resistance to Striga hermonthica at three locations in Nigeria and Mali. Results showed that many of the lines especially MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64 (Keninkédié) and the check SRN 39 remained resistant to Striga in all locations with low emerged Striga counts, while SAMSORG 14 had the highest Striga infestation in all locations. Considerable variation in reaction to Striga infestation was observed on Séguètana, 97-SB-F5DT-63 (Wasa), 97-SB-F5DT-65, CMDT 38, CMDT 39 and CMDT 45 which were susceptible to Striga at Samaru, Nigeria but were resistant to Striga at both locations in Mali. Based on low Striga resistance and high grain yield, lines MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64, 97-SB-F5DT-65, CMDT 39 and SAMSORT 14 have been nominated for wider evaluation across more West African countries. 相似文献
7.
Sergios A. Nicolaou Alan G. Fast Eiko Nakamaru-Ogiso Eleftherios T. Papoutsakis 《Applied and environmental microbiology》2013,79(23):7210-7219
Reactive oxygen species are generated by redox reactions and the Fenton reaction of H2O2 and iron that generates the hydroxyl radical that causes severe DNA, protein, and lipid damage. We screened Escherichia coli genomic libraries to identify a fragment, containing cueR, ybbJ, qmcA, ybbL, and ybbM, which enhanced resistance to H2O2 stress. We report that the ΔybbL and ΔybbM strains are more susceptible to H2O2 stress than the parent strain and that ybbL and ybbM overexpression overcomes H2O2 sensitivity. The ybbL and ybbM genes are predicted to code for an ATP-binding cassette metal transporter, and we demonstrate that YbbM is a membrane protein. We investigated various metals to identify iron as the likely substrate of this transporter. We propose the gene names fetA and fetB (for Fe transport) and the gene product names FetA and FetB. FetAB allows for increased resistance to oxidative stress in the presence of iron, revealing a role in iron homeostasis. We show that iron overload coupled with H2O2 stress is abrogated by fetA and fetB overexpression in the parent strain and in the Δfur strain, where iron uptake is deregulated. Furthermore, we utilized whole-cell electron paramagnetic resonance to show that intracellular iron levels in the Δfur strain are decreased by 37% by fetA and fetB overexpression. Combined, these findings show that fetA and fetB encode an iron exporter that has a role in enhancing resistance to H2O2-mediated oxidative stress and can minimize oxidative stress under conditions of iron overload and suggest that FetAB facilitates iron homeostasis to decrease oxidative stress. 相似文献
8.
Walter Fast Larry D. Sutton 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(8):1648-1659
Metallo-β-lactamases represent an emerging clinical threat due to their ability to render ineffective an entire class of antibiotics. Accordingly, this family of enzymes has been suggested as an attractive target for drug design. Progress toward developing effective inhibitors as well as the development of reporter substrates is reviewed. Inhibitors are classified into six classes and known binding interactions with metallo-β-lactamases are summarized. The development of chromogenic and fluorogenic reporter substrates is also reviewed with respect to current and prospective applications to future inhibitor and diagnostic discovery, mechanistic studies, and biological imaging. Despite progress in molecular probe development, the sequence and structural diversity within the metallo-β-lactamase family continue to present substantial hurdles for rational ligand design. 相似文献
9.
Bacillus thuringiensis crystal toxin: Ultrastructural studies of its effect on silkworm midgut cells
Bacillus thuringiensis crystal toxin induced a cytoplasmic response in columnar cells within 1 min after ingestion although external symptoms were not exhibited by larvae until 15 min after ingestion. Microvilli became less consistently uniform in diameter; their organized internal microfilaments were disrupted and disappeared. The cisternae of rough endoplasmic reticulum were enlarged and denuded of ribosomes. By 5 min after ingestion, microvilli of some columnar cells disappeared entirely and gross ultrastructural changes were observed in other regions of the cells. Up to 5 min after ingestion there were few, if any, ultrastructural changes observed within goblet cells. Mitochondria in columnar cells were swollen but did not exhibit the condensed configuration reported by other workers. Both the buffer system used in the fixation medium and its osmolarity influenced the changes in the ultrastructure of midgut cells exposed to B. thuringiensis crystal toxin. 相似文献
10.
Etienne Karita Matt A Price Shabir Lakhi William Kilembe Anatoli Kamali Eugene Ruzagira Eric Hunter Paul Farmer Susan Allen Gwynn Stevens Paramesh Chetty Sabrina Welsh Annie Yang Jill Gilmour Pat Fast The IAVI Africa HIV Prevention Partnership 《PloS one》2015,10(8)