298 research outputs found
Irreversible Thiol Oxidation in Carbonic Anhydrase III: Protection by S-Glutathiolation and Detection in Aging Rats
Proteins with reactive sulfhydryls are central to many important metabolic reactions and also contribute to a variety of signal transduction systems. In this re- port, we examine the mechanisms of oxidative dam- age to the two reactive sulfhydryls of carbonic anhy- drase III. Hydrogen peroxide (H2O2), peroxy radicals, or hypochlorous acid (HOCl) produced irreversibly oxidized forms, primarily cysteine sulfinic acid or cys- teic acid, of carbonic anhydrase III if glutathione (GSH) was not present. When GSH was approximate- ly equimolar to protein thiols, irreversible oxidation was prevented. H2O2 and peroxyl radicals both gener- ated S-glutathiolated carbonic anhydrase III via par- tially oxidized protein sulfhydryl intermediates, while HOCl did not cause S-glutathiolation. Thus, oxidative damage from H2O2 or AAPH was prevented by protein S-glutathiolation, while a direct reaction between GSH and oxidant likely prevents HOCl-mediated pro- tein damage. In cultured rat hepatocytes, carbonic anhydrase III was rapidly S-glutathiolated by mena- dione. When hepatocyte glutathione was depleted, menadione instead caused irreversible oxidation. We hypothesized that normal depletion of glutathione in aged animals might also lead to an increase in irre- versible oxidation. Indeed, both total protein extracts and carbonic anhydrase III contained significantly more cysteine sulfinic acid in older rats compared to young animals. These experiments show that, in the absence of sufficient GSH, oxidation reactions lead to irreversible protein sulfhydryl damage in purified pro- teins, cellular systems, and whole animals
Glucose Reaction with Fumonisin B1 Partially Reduces Its Toxicity in Swine
Acute and subacute intraperitoneal doses of fumonisin B1 (FB1) were administered to test the efficacy of the FB1-glucose reaction products in detoxifying FB1 in swine. In the acute study at 11 µmol of FB1/kg of body weight, five of six pigs administered FB1 and four of six pigs administered FB1- glucose died from acute pulmonary edema. Analysis of weight gain, serum aspartate aminotransferase and γ-glutamyltransferase, total cholesterol, and pathological evaluation did not provide evidence of protection against FB1 toxicity by the FB1-glucose reaction products. In the subacute study at 5.5 µmol of FB1/kg of body weight, one pig administered FB1 died from liver damage. Analysis of serum aspartate aminotransferase, γ-glutamyltransferase, and total bilirubin showed protection against FB1 toxicity by the FB1-glucose reaction products. The levels of sphinganine and sphinganine/sphingosine ratios in serum and liver as well as pathologic findings provided definitive evidence of protection against the FB1 toxic effects by this detoxification procedure (p \u3c 0.05)
Fumonisin B-Glucose Reaction Products Are Less Toxic When Fed to Swine
The effects of fumonisin B-glucose reaction products in swine diets was examined. Pigs were fed diets containing 528 µmol of total fumonisin B/kg (FB), 528 µmol of total FB-glucose adducts/kg (FB-G, 122 µmol of unreacted FB/kg), or 0 µmol of total FB/kg for 15 days to test the efficacy of the FB-G reaction products in detoxifying FB. Weight gain in FB pigs was lower than in FB-G or controls, which was correlated with feed intake reduction in FB pigs. Serum aspartate aminotransferase, γ-glutamyltransferase, and total bilirubin in FB pigs were higher than in FB-G or control pigs. Serum sphinganine/shingosine ratios in FB pigs were higher than in FB-G or control pigs. Microscopic examination of tissues from FB pigs showed generalized liver necrosis and apoptosis with marked cellular pleomorphism and disorganized hepatic cords. The liver and kidneys in the FB-G group appeared to be normal. Tissues of controls were free of lesions. Results suggest that dietary FB-G products are less toxic to swine and may provide an detoxification approach in instances of widespread FB grain contamination (p \u3c 0.05)
A new species of Agaporomorphus Zimmermann, 1921 from Peru (Coleoptera, Dytiscidae, Copelatinae)
Agaporomorphus julianeae sp. n. is described from the Biological Field Station Panguana, in Huanuco province of central Peru. The new species belongs to the A. knischi-group sensu Miller 2005. Together with A. knischi Zimmermann, 1921 and A. colberti Miller & Wheeler, 2008 this is the third species of the genus with broadly enlarged male antennomeres. The new species can be separated from A. colberti and A. knischi by the smaller please expanded male antennomere VIII, and the form of the median lobe. Important species characters (median lobe, male antennae, metafemur, colour pattern) of the new species and A. knischi are figured, and the habitat, a temporary blackwater forest pond, and its species rich water beetle coenosis are illustrated and described in detail. The Brazilian A. mecolobus Miller, 2001, only known from the type material from Sao Paulo, is here recorded for Minas Gerais. Habitus photos of four additional Agaporomorphus species and Hydrodytes opalinus (Zimmermann, 1921) are provided. Altogether ten species of Agaporomorphus are now known
Mosaic patterns of diversification dynamics following the colonization of Melanesian islands
The fate of newly settled dispersers on freshly colonized oceanic islands is a central theme of island biogeography. The emergence of increasingly sophisticated methods of macroevolutionary pattern inference paves the way for a deeper understanding of the mechanisms governing these diversification patterns on lineages following their colonization of oceanic islands. Here we infer a comprehensive molecular phylogeny for Melanesian Exocelina diving beetles. Recent methods in historical biogeography and diversification rate inference were then used to investigate the evolution of these insects in space and time. An Australian origin in the mid-Miocene was followed by independent colonization events towards New Guinea and New Caledonia in the late Miocene. One colonization of New Guinea led to a large radiation of >150 species and 3 independent colonizations of New Caledonia gave rise to about 40 species. The comparably late colonizations of Vanuatu, Hawaii and China left only one or two species in each region. The contrasting diversification trajectories of these insects on Melanesian islands are likely accounted for by island size, age and availability of ecological opportunities during the colonization stage
Taxonomy and Biogeography without frontiers – WhatsApp, Facebook and smartphone digital photography let citizen scientists in more remote localities step out of the dark
Taxonomy and biogeography can benefit from citizen scientists. The use of social networking and open access cooperative publishing can easily connect naturalists even in more remote areas with in-country scientists and institutions, as well as those abroad. This enables taxonomic efforts without frontiers and at the same time adequate benefit sharing measures.
We present new distribution and habitat data for diving beetles of Bali island, Indonesia, as a proof of concept. The species Hydaticus luczonicus Aubé, 1838 and Eretes griseus (Fabricius, 1781) are reported from Bali for the first time. The total number of Dytiscidae species known from Bali is now 34
Barcoding Fauna Bavarica – Capturing Central European Animal Diversity
The Barcoding Fauna Bavarica (BFB) is an All Species
Barcoding campaign ran by the Zoologische Staatssammlung in
Munich and the Canadian Centre for DNA Barcoding (www.
faunabavarica.de). Core funding comes from the Bavarian Ministry
for Science, Research and the Arts and from Genome Canada
through the Ontario Genomics Institute. The initial funding period is
from 2009–2013. Bavaria has the highest biodiversity of all German
states, with at least 35000 animal species reported, representing a
significant portion of the central European species diversity.
Ecoregions include high altitude biomes, foothill areas and forested
lowlands. The Zoologische Staatssammlung (ZSM) is one of the
largest German natural history research institutions. It holds the
world’s largest collection of Lepidoptera and Germany’s largest
Hymenoptera collection. Since mid-2009, the BFB project has
contributed DNA barcode records from 7208 specimens representing
3000 species and is therefore, after less than one year, one of the
most comprehensive sources for local DNA barcode data. The focus
groups for the initial phase were Lepidoptera (1820 species
barcoded), bees (316 species), ants (39 species) and aquatic insects
(322 species). Work on these focal groups will continue during 2010,
with the goal to complete 80% of the Bavarian focal group species by
the end of the year. New focal groups are Diptera, Mollusca, all
Vertebrata and terrestrial Coleoptera, targeting 2000 species in 2010.
Most tissue samples come from specimens in the ZSM collection,
and where this was not feasible from freshly collected and identified
specimens. This rapid progress reflects the strong involvement of
taxonomists throughout the process, which is one of our key missions.
We have implemented a system which co-ordinates vouchers stored
in our main collection, with tissues as well as DNA samples in our
DNA bank
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Pleistocene climate change promoted rapid diversification of aquatic invertebrates in Southeast Australia
Background: The Pleistocene Ice Ages were the most recent geohistorical event of major global impact, but their consequences for most parts of the Southern hemisphere remain poorly known. We investigate a radiation of ten species of Sternopriscus, the most species-rich genus of epigean Australian diving beetles. These species are distinct based on genital morphology but cannot be distinguished readily by mtDNA and nDNA because of genotype sharing caused by incomplete lineage sorting. Their genetic similarity suggests a Pleistocene origin. Results: We use a dataset of 3858 bp of mitochondrial and nuclear DNA to reconstruct a phylogeny of Sternopriscus using gene and species trees. Diversification analyses support the finding of a recent rapid speciation event with estimated speciation rates of up to 2.40 species per MY, which is considerably higher than the proposed average rate of 0.16 species per MY for insects. Additionally, we use ecological niche modeling and analyze data on habitat preferences to test for niche divergence between species of the recent Sternopriscus radiation. These analyses show that the species can be characterized by a set of ecological variables referring to habitat, climate and altitude. Conclusions: Our results suggest that the repeated isolation of populations in glacial refugia might have led to divergent ecological adaptations and the fixation of morphological traits supporting reproductive isolation and therefore may have promoted speciation. The recent Sternopriscus radiation fulfills many characteristics of a species flock and would be the first described example of an aquatic insect species flock. We argue that the species of this group may represent a stage in speciation past the species flock condition because of their mostly broad and often non-overlapping ranges and preferences for different habitat types.Organismic and Evolutionary Biolog
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