Species differences in acrylonitrile metabolism and toxicity between experimental animals and humans based on observations in human accidental poisonings

The high acute toxicity of acrylonitrile may be a result of its intrinsic biological reactivity or of its metabolite cyanide. Intravenous N-acetylcysteine has been recommended for treatment of accidental intoxications in acrylonitrile workers, but such recommendations vary internationally. Acrylonitrile is metabolized in humans and experimental animals via two competing pathways; the glutathione-dependent pathway is considered to represent an avenue of detoxication whilst the oxidative pathway leads to a genotoxic epoxide, cyanoethylene oxide, and to elimination of cyanide. Cases of acute acrylonitrile overexposure or intoxication have occurred within persons having industrial contact with acrylonitrile; the route of exposure was by inhalation and/or by skin contact. The combined observations lead to the conclusion of a much higher impact of the oxidative metabolism of acrylonitrile in humans than in rodents. This is confirmed by differences in the clinical picture of acute life-threatening intoxications in both species, as well as by differential efficacies of antidotes. A combination of N-acetylcysteine with sodium thiosulfate seems an appropriate measure for antidote therapy of acute acrylonitrile intoxications. Clinical observations also highlight the practical importance of human individual susceptibility differences. Furthermore, differential adduct monitoring, assessing protein adducts with different rates of decay, enables the development of more elaborated biological monitoring strategies for the surveillance of workers with potential acrylonitrile contact.

Species differences in the glutathione transferase GSTT1-1 activity towards the model substrates methyl chloride and dichloromethane in liver and kidney

Glutathione transferase (GST) GSTT1-1 is involved in the biotransformation of several chemicals widely used in industry, such as butadiene and dichloro methane DCM. The polymorphic hGSTT1-1 may well play a role in the development of kidney tumours after high and long-term occupational exposure against trichloroethylene. Although several studies have investigated the association of this polymorphism with malignant diseases little is known about its enzyme activity in potential extrahepatic target tissues. The known theta-specific substrates methyl chloride (MC) dichloromethane and 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) were used to assay GSTT1-1 activity in liver and kidney of rats, mice, hamsters and humans differentiating the three phenotypes (non-conjugators, low conjugators, high conjugators) seen in humans. In addition GSTT1-1 activity towards MC and DCM was determined in human erythrocytes. No GSTT1-1 activity was found in any tissue of non-conjugators (NC). In all organs high conjugators (HC) showed twofold higher activity towards MC and DCM than low conjugators (LC). The activity in human samples towards EPNP was too close to the detection limit to differentiate between the three conjugator phenotypes. GSTT1-1 activity towards MC was two to seven-times higher in liver cytosol than in kidney cytosol. The relation for MC between species was identical in both organs: mouse > HC > rat > LC > hamster > NC. In rats, mice and hamsters GSTT1-1 activity in liver cytosol towards DCM was also two to seven-times higher than in the kidney cytosol. In humans this activity was twice as high in kidney cytosol than in liver cytosol. The relation between species was mouse > rat > HC > LC > hamster > NC for liver, but mouse > HC > LC/rat > hamster/NC for kidney cytosol. The importance to heed the specific environment at potential target sites in risk assessment is emphasized by these results.

Capturing natural-colour 3D models of insects for species discovery and diagnostics

Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity - past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens "from all angles" and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. ("Natural-colour" is used to contrast with "false-colour", i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research, education, art, entertainment, biodiversity assessment and biosecurity control. © 2014 Nguyen et al.

High-performance gel filtration patterns of venoms from three species of wasps of the genus Polybia (hymenoptera, vespidae).

The profiles of high-performance gel filtration of venoms from Polybia paulista, Polybia ignobilis and Polybia occidentalis occidentalis showed 13 peaks distributed among the three species. These profiles presented similarities that permitted the chromatographic characterization of the genus Polybia and differences that permitted the identification of each species studied. Thus, the comparative analysis of chromatographic profiles of high-performance gel filtration of venoms may be used as an auxiliary tool in taxonomic studies of Polybia wasps.

Separation of flavonoids and naphthopyrones from four Brazilian Paepalanthus species by droplet countercurrent chromatography

A general procedure was developed for the simultaneous separation of flavonoids and naphthopyrones from the polar extracts of the capitula from Brazilian everlasting plants is described. The ethanolic extracts of several species from the Paepalanthus genus (Eriocaulaceae) were fractionated by droplet countercurrent chromatography followed by column chromatography on pvp and sephadex LH-20. The isolated compounds were identified by spectrometric analysis and comparison with literature data. This approach led to the isolation of 9-O-β-D-glucopyranosylpaepalantine (1), 9-O-β-D-glucopyranosyl (1→6)allopyranosylpaepalantine (2), along with the flavonoids 6-methoxykaempferol (3), 3-O-β-D-glucopyranosyl-6-methoxykaempferol (4), patuletin (5), 3-Oβ-D-rutinosylpatuletin (6), 7-O-β-D-glucopyranosylquercetagetin (7), 5,7,4'-trihydroxy-6,3'-dimethoxyflavone (8) and 5,7,4'-trihydroxy-6,3'-dimethoxyflavonol (9).

rDNA-RFLP identification of Candida species in immunocompromised and seriously diseased patients

PCR was used to amplify a targeted region of the ribosomal DNA of 76 Candida spp. isolates from immunocompromised and seriously diseased patients. Thirty-seven strains isolated from different anatomical sites of 11 patients infected with HIV (Vitória, ES, Brazil), 26 isolates from patients under treatment at Odilon Behrens Hospital and 13 isolates from skin and urine samples from São Marcos Clinical Analysis Laboratory (Belo Horizonte, Brazil) were scored. Fragments of rDNA were amplified using primer pairs ITS1-ITS4, for the amplification of ITS1 and ITS2 regions, including the gene for the 5.8s subunit. Amplification resulted in fragments ranging in size from 350 to 950 bp. Amplicons were digested with eight restriction enzymes. A pattern of species-specificity among the different medically important Candida species could be identified following restriction digestion of the PCR products. Candida albicans was the species most frequently observed, except for the group of newborns under treatment at the Odilon Behrens Hospital and for the isolates from the clinical analysis laboratory. C. parapsilosis was the species most frequently observed in these two groups.

Strong selection against hybrids at a hybrid zone in the Ensatina ring species complex and its evolutionary implications

The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders E. eschscholtzii xanthoptica and E. eschscholtzii platensis hybridize in the central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was resampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (1) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730 m to 2000 m; (2) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over five generations; (3) there were very few if any putative F1s, but a relatively high number of backcrossed individuals in the central portion of transects: and (4) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit showed maximum values near the center of the zones. Using estimates of cline width and dispersal, we infer strong selection against hybrids. This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent selection and reinforces the value of Ensatina as a system for the study of divergence and speciation at multiple stages. © 2005 The Society for the Study of Evolution. All rights reserved.

Evaluating the karyotypic diversity in species of Hyla (Anura, Hylidae) with 2n = 30 chromosomes based on the analysis of ten species

Ten species of Hyla with 2n = 30 from Brazilian fauna were analysed cytogenetically. Hyla minuta is the unique presenting all bi-armed metacentric or submetacentric chromosomes in the karyotype, therefore, with the highest FN = 60. The remaining species have a variable number of uni-armed telocentric or subtelocentric chromosomes: H. cruzi, H. elianeae, and H. rubicundula with three pairs (FN = 54), H. berthalutzae, H. elegans, H. microps, and H. nana with four pairs (FN = 52), and H. nahdereri and H. sanborni with five pairs (FN = 50). The uni-armed elements are among pairs 5, 6, 7, 11, 14, and 15, which also appeared with metacentric or submetacentric morphology. The remaining chromosome pairs 1, 2, 3, 4, 8, 9, 10, 12, and 13 were never found to be telocentric or subtelocentric. AgNOR patterns are species-specific, the majority of the species exhibiting a single pair with AgNORs, with the exception of H. elegans and H. nana with more than one chromosome pair bearing this cytological marker. C banding was obtained in H. berthalutzae, H. cruzi, H. elegans, H. elianeae, H. microps, H. minuta, H. nahdereri, and H. nana, which showed positively stained centromeric heterochromatin. Our analysis confirms the great karyotypic diversity in the species of Hyla with 2n = 30, with no species sharing identical karyotypes.

Localization of rDNA sites in holocentric chromosomes of three species of triatomines (Heteroptera, Triatominae).

Chromatin organization in the holocentric chromosomes of three triatomines species was cytologically studied by fluorescent in situ hybridization with a 45S rDNA probe of Drosophila melanogaster to localize ribosomal genes. In Triatoma tibiamaculata, metaphases I showed telomeric highlights in a single, larger bivalent. In T. protacta, hybridization was detected in one of the telomeres of an autosomal chromosome. In T. platensis, there were highlights in a single, smaller chromosome (X chromosome). The results obtained did not agree with the expected localization of rDNA genes in the sex chromosomes of triatomines, as demonstrated by silver impregnation, and suggest that the chromosome reorganization that occurred in this group during evolution may be a more important mechanism involved in rDNA distribution.

Taxonomic and phylogenetic relationships between neotropical species of ticks from genus Amblyomma (Acari: Ixodidae) inferred from second internal transcribed spacer sequences of rDNA

The accurate specific identification of ticks is essential for the study, control and prevention of tick-borne diseases. Herein, we determined ribosomal nucleotide sequences of the second internal transcribed spacer (ITS2) of 15 Neotropical hard tick species of the genus Amblyomma Koch found in Brazil. Most of the studied ticks accidentally parasite humans and potentially act as vectors of zoonoses. Lengths of the ITS2 sequences ranged from 956 to 1,207 bp, whereas GC content varied from 62.4 to 66.9%. A matrix of ITS2 divergence was calculated with the ITS2 sequence data obtained showing divergence levels varying from 1.5 to 28.8%. The analysis indicated that this molecular marker can be useful for Amblyomma-specific identification. Phylogenetic inferences based on the ITS2 sequences were used to assess some issues in subgenus taxonomy. © 2007 Entomological Society of America.

True branched nostocalean cyanobacteria from tropical aerophytic habitats and molecular assessment of two species from field samples

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

PRP8 intein in cryptic species of Histoplasma capsulatum: Evolution and phylogeny

The PRP8 intein is the most widespread intein among the Kingdom Fungi. This genetic element occurs within the prp8 gene, and is transcribed and translated simultaneously with the gene. After translation, the intein excises itself from the Prp8 protein by an autocatalytic splicing reaction, subsequently joining the N and C terminals of the host protein, which retains its functional conformation. Besides the splicing domain, some PRP8 inteins also have a homing endonuclease (HE) domain which, if functional, makes the intein a mobile element capable of becoming fixed in a population. This work aimed to study (1) The occurrence of this intein in Histoplasma capsulatum isolates (n=. 99) belonging to different cryptic species collected in diverse geographical locations, and (2) The functionality of the endonuclease domains of H. capsulatum PRP8 inteins and their phylogenetic relationship among the cryptic species. Our results suggest that the PRP8 intein is fixed in H. capsulatum populations and that an admixture or a probable ancestral polymorphism of the PRP8 intein sequences is responsible for the apparent paraphyletic pattern of the LAmA clade which, in the intein phylogeny, also encompasses sequences from LAmB isolates. The PRP8 intein sequences clearly separate the different cryptic species, and may serve as an additional molecular typing tool, as previously proposed for other fungi genus, such as Cryptococcus and Paracoccidioides. © 2013 Elsevier B.V.

Description of three new species of Hepatozoon (Apicomplexa, Hepatozoidae) from Rattlesnakes (Crotalus durissus terrificus) based on molecular, morphometric and morphologic characters

Hepatozoon spp. are commonly found infecting snakes. Since the latter are parasitized by diverse forms and data in the literature show divergence, we studied Hepatozoon spp. diversity on Crotalus durissus terrificus snakes using both molecular and morphological approaches. Naturally infected animals were employed. Blood was collected, blood smears were prepared and an aliquot was stored at -20. °C for DNA extraction. Five specimens of C. durissus terrificus were selected, each of them infected with one gamont type. Morphological and morphometric analyses of the found gamonts led to their grouping into three populations. For molecular characterization, seven oligonucleotide pairs that amplify distinct regions of rDNA gene were tested by adopting the PCR technique. Only the oligonucleotide pairs HepF300/Hep900 and HEMO1/HEMO2 were efficient in amplifying and distinguishing different isolates of Hepatozoon spp. from snakes. The better results were obtained when both oligonucleotide pairs were used in association. Based on the molecular and morphologic differences, three new species were proposed: Hepatozoon cuestensis sp. nov.; Hepatozoon cevapii sp. nov. and Hepatozoon massardii sp. nov. This is the first description of new Hepatozoon species from snakes, based on molecular characterization and morphological data, in South America. © 2013 Elsevier Inc.

Production and carbon allocation in monocultures and mixed-species plantations of Eucalyptus grandis and Acacia mangium in Brazil

Introducing nitrogen-fixing tree species in fast-growing eucalypt plantations has the potential to improve soil nitrogen availability compared with eucalypt monocultures. Whether or not the changes in soil nutrient status and stand structure will lead to mixtures that out-yield monocultures depends on the balance between positive interactions and the negative effects of interspecific competition, and on their effect on carbon (C) uptake and partitioning. We used a C budget approach to quantify growth, C uptake and C partitioning in monocultures of Eucalyptus grandis (W. Hill ex Maiden) and Acacia mangium (Willd.) (treatments E100 and A100, respectively), and in a mixture at the same stocking density with the two species at a proportion of 1 : 1 (treatment MS). Allometric relationships established over the whole rotation, and measurements of soil CO2 efflux and aboveground litterfall for ages 4-6 years after planting were used to estimate aboveground net primary production (ANPP), total belowground carbon flux (TBCF) and gross primary production (GPP). We tested the hypotheses that (i) species differences for wood production between E. grandis and A. mangium monocultures were partly explained by different C partitioning strategies, and (ii) the observed lower wood production in the mixture compared with eucalypt monoculture was mostly explained by a lower partitioning aboveground. At the end of the rotation, total aboveground biomass was lowest in A100 (10.5 kg DM m(-2)), intermediate in MS (12.2 kg DM m(-2)) and highest in E100 (13.9 kg DM m(-2)). The results did not support our first hypothesis of contrasting C partitioning strategies between E. grandis and A. mangium monocultures: the 21% lower growth (delta B-w) in A100 compared with E100 was almost entirely explained by a 23% lower GPP, with little or no species difference in ratios such as TBCF/GPP, ANPP/TBCF, delta B-w/ANPP and delta B-w/GPP. In contrast, the 28% lower delta B-w in MS than in E100 was explained both by a 15% lower GPP and by a 15% lower fraction of GPP allocated to wood growth, thus partially supporting our second hypothesis: mixing the two species led to shifts in C allocations from above- to belowground, and from growth to litter production, for both species.

Species-Specific Relationships between Water Transparency and Male Coloration within and between Two Closely Related Lake Victoria Cichlid Species

Environmental variation in signalling conditions affects animal communication traits, with possible consequences for sexual selection and reproductive isolation. Using spectrophotometry, we studied how male coloration within and between populations of two closely related Lake Victoria cichlid species (Pundamilia pundamilia and P. nyererei) covaries with water transparency. Focusing on coloration patches implicated in sexual selection, we predicted that in clear waters, with broad-spectrum light, (1) colours should become more saturated and (2) shift in hue away from the dominant ambient wavelengths, compared to more turbid waters. We found support for these predictions for the red and yellow coloration of P. nyererei but not the blue coloration of P. pundamilia. This may be explained by the species difference in depth distribution, which generates a steeper gradient in visual conditions for P. nyererei compared to P. pundamilia. Alternatively, the importance of male coloration in intraspecific sexual selection may differ between the species. We also found that anal fin spots, that is, the orange spots on male haplochromine anal fins that presumably mimic eggs, covaried with water transparency in a similar way for both species. This is in contrast to the other body regions studied and suggests that, while indeed functioning as signals, these spots may not play a role in species differentiation.