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Sample records for parthenogenetic species dactylobiotus

  1. Dactylobiotus luci , a new freshwater tardigrade (Eutardigrada ...

    African Journals Online (AJOL)

    A new freshwater eutardigrade, Dactylobiotus luci sp. nov., is described from a permanent marsh pool (Zaphania's Pool) at 4225 m elevation in the Alpine zone of the Rwenzori Mountains, Uganda. The new species is most similar to D. dervizi Biserov, 1998 in the shape of the egg processes, absence of papillae and ...

  2. Cytogenetics of a parthenogenetic Arctic species of Micropsectra (Diptera, Chironomidae)

    Science.gov (United States)

    Porter, David L.; Martin, Jon

    2011-01-01

    Abstract Micropsectra sedna (Oliver, 1976) is a parthenogenetic midge from the Canadian Arctic. The parthenogenetic mechanism is apomictic thelytoky, with a restitutional division during oogenesis, as found in other parthenogenetic Chironomidae. It is triploid, with two similar chromosome sets, and the third is relatively dissimilar, pairing little with the diploid set. Two karyotypes were observed: a single individual with eight polytene elements in the salivary glands (3n=12), considered standard, while the majority of larvae showed only seven polytene chromosomes (3n=11). Hybrid speciation is considered likely, although chromosomal recombination following the origin of thelytoky has played some part in karyotype evolution. A single morphologically distinct larva was also found, which might be the donor of the haploid chromosome set. The apomictic restitutional system is compared to that of the other, independently derived, parthenogenetic Chironomids to assess the extent of similarity between species. PMID:24260638

  3. [Intra- and interspecific polymorphism of (AAT)n in microsatellite locus du47D in parthenogenetic species of the genus Darevskia].

    Science.gov (United States)

    Korchagin, V I; Vergun, A A; Godakova, S A; Tokarskaia, O N

    2013-03-01

    The molecular structure of the allelic variants of (AAT)n of the Du47D microsatellite locus was determined in parthenogenetic lizards Darevskia dahli, D. armeniaca, and D. rostombekovi. Comparative analysis of these alleles showed that they were characterized by perfect structure of microsatellite cluster, and were different in the number of (AAT) monomeric units, as well as in the combinations of species-specific substitutions and deletions in the microsatellite flanking regions. Molecular structure of microsatellite cluster, species-specific single nucleotide polymorphism (SNP), and different representation of alleles Du47 in the samples of parthenogenetic species examined point to the origin of the alleles from different bisexual species, which is consistent with the hybrid nature of unisexual species of the genus Darevskia. In addition, these data reflect different combination patterns of interspecific hybridization events with the participation of the same bisexual species upon the formation of hybrid genomes of parthenogenetic species. Possible application of the allelic variants of microsatellite loci of parthenogenetic lizards as the genetic markers for the analysis of the genomes of parthenogenetic species in the light of evolution, ecology, and parthenogenetic type of reproduction in vertebrates is discussed.

  4. Species delimitation in asexual insects of economic importance: The case of black scale (Parasaissetia nigra, a cosmopolitan parthenogenetic pest scale insect.

    Directory of Open Access Journals (Sweden)

    Yen-Po Lin

    Full Text Available Asexual lineages provide a challenge to species delimitation because species concepts either have little biological meaning for them or are arbitrary, since every individual is monophyletic and reproductively isolated from all other individuals. However, recognition and naming of asexual species is important to conservation and economic applications. Some scale insects are widespread and polyphagous pests of plants, and several species have been found to comprise cryptic species complexes. Parasaissetia nigra (Nietner, 1861 (Hemiptera: Coccidae is a parthenogenetic, cosmopolitan and polyphagous pest that feeds on plant species from more than 80 families. Here, we implement multiple approaches to assess the species status of P. nigra, including coalescence-based analyses of mitochondrial and nuclear genes, and ecological niche modelling. Our results indicate that the sampled specimens of P. nigra should be considered to comprise at least two ecotypes (or "species" that are ecologically differentiated, particularly in relation to temperature and moisture. The presence of more than one ecotype under the current concept of P. nigra has implications for biosecurity because the geographic extent of each type is not fully known: some countries may currently have only one of the biotypes. Introduction of additional lineages could expand the geographic extent of damage by the pest in some countries.

  5. [Reticulate evolution of parthenogenetic species of the Lacertidae rock lizards: inheritance of CLsat tandem repeats and anonymous RAPD markers].

    Science.gov (United States)

    Chobanu, D; Rudykh, I A; Riabinina, N L; Grechko, V V; Kramerov, D A; Darevskiĭ, I S

    2002-01-01

    The genetic relatedness of several bisexual and of four unisexual "Lacerta saxicola complex" lizards was studied, using monomer sequences of the complex-specific CLsat tandem repeats and anonymous RAPD markers. Genomes of parthenospecies were shown to include different satellite monomers. The structure of each such monomer is specific for a certain pair of bisexual species. This fact might be interpreted in favor of co-dominant inheritance of these markers in bisexual species hybridogenesis. This idea is supported by the results obtained with RAPD markers; i.e., unisexual species genomes include only the loci characteristic of certain bisexual species. At the same time, in neither case parthenospecies possess specific, autoapomorphic loci that were not present in this or that bisexual species.

  6. "Sexual" behavior in parthenogenetic lizards (Cnemidophorus).

    Science.gov (United States)

    Crews, D; Fitzgerald, K T

    1980-01-01

    All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Basic data on the behavior of parthenogens are lacking, however. We have discovered, from observations of captive Cnemidophorus uniparens, C. velox, and C. tesselatus, behavior patterns remarkably similar to the courtship and copulatory behavior of closely related sexual species. Briefly, in separately housed pairs, one lizard was repeatedly seen to mount and ride its cagemate and appose the cloacal regions. Dissection or palpation revealed that, in each instance, the courted animal was reproductively active, having ovaries containing large, preovulatory follicles, while the courting animal was either reproductively inactive or postovulatory, having ovaries containing only small, undeveloped follicles. These observations are significant for the questions they raise. For example, is this behavior a nonfunctional vestige of the species' ancestry, or is this behavior necessary for successful reproduction in the species (e.g., by priming reproductive neuroendocrine mechanisms as has been demonstrated in sexual species)?

  7. Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards.

    Science.gov (United States)

    Lutes, Aracely A; Neaves, William B; Baumann, Diana P; Wiegraebe, Winfried; Baumann, Peter

    2010-03-11

    Although bisexual reproduction has proven to be highly successful, parthenogenetic all-female populations occur frequently in certain taxa, including the whiptail lizards of the genus Aspidoscelis. Allozyme analysis revealed a high degree of fixed heterozygosity in these parthenogenetic species, supporting the view that they originated from hybridization events between related sexual species. It has remained unclear how the meiotic program is altered to produce diploid eggs while maintaining heterozygosity. Here we show that meiosis commences with twice the number of chromosomes in parthenogenetic versus sexual species, a mechanism that provides the basis for generating gametes with unreduced chromosome content without fundamental deviation from the classic meiotic program. Our observation of synaptonemal complexes and chiasmata demonstrate that a typical meiotic program occurs and that heterozygosity is not maintained by bypassing recombination. Instead, fluorescent in situ hybridization probes that distinguish between homologues reveal that bivalents form between sister chromosomes, the genetically identical products of the first of two premeiotic replication cycles. Sister chromosome pairing provides a mechanism for the maintenance of heterozygosity, which is critical for offsetting the reduced fitness associated with the lack of genetic diversity in parthenogenetic species.

  8. “Sexual” behavior in parthenogenetic lizards (Cnemidophorus)

    OpenAIRE

    Crews, David; Fitzgerald, Kevin T.

    1980-01-01

    All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Basic data on the behavior of parthenogens are lacking, however. We have discovered, from observations of captive Cnemidophorus uniparens, C. velox, and C. tesselatus, behavior patterns remarkably similar to the courtship and copulatory behavior of closely related sexual species. Briefly, in separately housed pairs, one lizard was repeatedly seen to mount and ride its cagema...

  9. Switch from sexual to parthenogenetic reproduction in a zebra shark.

    Science.gov (United States)

    Dudgeon, Christine L; Coulton, Laura; Bone, Ren; Ovenden, Jennifer R; Thomas, Severine

    2017-01-16

    Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating. The demonstration of parthenogenesis in these two conspecific individuals with different sexual histories provides further support that elasmobranch fishes may flexibly adapt their reproductive strategy to environmental circumstances.

  10. Inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (Meloidogyne spp.) as revealed by a bacterial parasite (Pasteuria penetrans).

    Science.gov (United States)

    Davies, K G; Rowe, J A; Williamson, V M

    2008-06-01

    Specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the Gram-positive bacterial hyperparasite Pasteuria penetrans. This bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. Endospore attachment of P. penetrans populations to second-stage juveniles of the root-knot nematode species Meloidogyne incognita and Meloidogyne hapla showed there were interactive differences between bacterial populations and nematode species. Infected females of M. incognita produced a few progeny which were used to establish two nematode lines from single infective juveniles encumbered with either three or 26 endospores. Single juvenile descent lines of each nematode species were produced to test whether cuticle variation was greater within M. hapla lines that reproduce by facultative meiotic parthenogenesis than within lines of M. incognita, which reproduces by obligate parthenogenesis. Assays revealed variability between broods of individual females derived from single second-stage juvenile descent lines of both M. incognita and M. hapla suggesting that progeny derived from a single individual can differ in spore adhesion in both sexual and asexual nematode species. These results suggest that special mechanisms that produced these functional differences in the cuticle surface may have evolved in both sexually and asexually reproducing nematodes as a strategy to circumvent infection by this specialised hyperparasite.

  11. High hydrostatic pressure treatment of porcine oocytes induces parthenogenetic activation

    DEFF Research Database (Denmark)

    Lin, Lin; Pribenszky, Csaba; Molnár, Miklós

    2010-01-01

    An innovative technique called high hydrostatic pressure (HHP) treatment has recently been reported to improve the cryosurvival of gametes and embryos in certain mammalian species, including the mouse, pig, and cattle. In the present study the parthenogenetic activation (PA) of pig oocytes caused...... by HHP treatment was investigated in different holding media with or without Ca(2+). The efficiency of activation was tested at different pressure levels and media including T2 (HEPES-buffered TCM-199 containing 2% cattle serum), and mannitol-PVA fusion medium with (MPVA + Ca(2+)) or without Ca(2...

  12. Wolbachia endosymbiont is essential for egg hatching in a parthenogenetic arthropod.

    NARCIS (Netherlands)

    Timmermans, M.J.T.N.; Ellers, J.

    2009-01-01

    Wolbachia pipientis can induce a range of sex ratio distortions including parthenogenesis. Recently Wolbachia has been detected in the diploid, parthenogenetic, collembolan species Folsomia candida. In this paper we address the effect of Wolbachia on reproduction in F. candida. Wolbachia infection

  13. MITOCHONDRIAL DNA ANALYSES AND THE ORIGIN AND RELATIVE AGE OF PARTHENOGENETIC CNEMIDOPHORUS: PHYLOGENETIC CONSTRAINTS ON HYBRID ORIGINS.

    Science.gov (United States)

    Moritz, C; Wright, J W; Brown, W M

    1992-02-01

    Within the genus Cnemidophorus, parthenogenesis has arisen by hybridization several times. This provides the opportunity to investigate general features of hybridization events that result in the formation of parthenogenetic lineages. The relationships of mtDNA from all bisexual species of Cnemidophorus known to be parents of parthenogens were investigated to evaluate phylogenetic constraints on the hybrid-origin of parthenogenesis. No phylogenetic clustering of the parental species, either maternal or paternal, was apparent. However, the combination of bisexual species that have resulted in parthenogenetic lineages are generally distantly related or genetically divergent. This contrasts with the expectation if parthenogenesis in hybrids is due to the action of a single rare allele, but is consistent with the hypothesis that some minimal level of divergence is necessary to stimulate parthenogenetic reproduction in hybrids. © 1992 The Society for the Study of Evolution.

  14. “Sexual” behavior in parthenogenetic lizards (Cnemidophorus)

    Science.gov (United States)

    Crews, David; Fitzgerald, Kevin T.

    1980-01-01

    All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Basic data on the behavior of parthenogens are lacking, however. We have discovered, from observations of captive Cnemidophorus uniparens, C. velox, and C. tesselatus, behavior patterns remarkably similar to the courtship and copulatory behavior of closely related sexual species. Briefly, in separately housed pairs, one lizard was repeatedly seen to mount and ride its cagemate and appose the cloacal regions. Dissection or palpation revealed that, in each instance, the courted animal was reproductively active, having ovaries containing large, preovulatory follicles, while the courting animal was either reproductively inactive or postovulatory, having ovaries containing only small, undeveloped follicles. These observations are significant for the questions they raise. For example, is this behavior a nonfunctional vestige of the species' ancestry, or is this behavior necessary for successful reproduction in the species (e.g., by priming reproductive neuroendocrine mechanisms as has been demonstrated in sexual species)? Images PMID:16592761

  15. Widespread failure to complete meiosis does not impair fecundity in parthenogenetic whiptail lizards.

    Science.gov (United States)

    Newton, Aracely A; Schnittker, Robert R; Yu, Zulin; Munday, Sarah S; Baumann, Diana P; Neaves, William B; Baumann, Peter

    2016-12-01

    Parthenogenetic species of whiptail lizards in the genus Aspidoscelis constitute a striking example of speciation by hybridization, in which first-generation hybrids instantly attain reproductive isolation and procreate as clonal all-female lineages. Production of eggs containing a full complement of chromosomes in the absence of fertilization involves genome duplication prior to the meiotic divisions. In these pseudo-tetraploid oocytes, pairing and recombination occur exclusively between identical chromosomes instead of homologs; a deviation from the normal meiotic program that maintains heterozygosity. Whether pseudo-tetraploid cells arise early in germ cell development or just prior to meiosis has remained unclear. We now show that in the obligate parthenogenetic species A. neomexicana the vast majority of oocytes enter meiosis as diploid cells. Telomere bouquet formation is normal, but synapsis fails and oocytes accumulate in large numbers at the pairing stage. Pseudo-tetraploid cells are exceedingly rare in early meiotic prophase, but they are the only cells that progress into diplotene. Despite the widespread failure to increase ploidy prior to entering meiosis, the fecundity of parthenogenetic A. neomexicana is similar to that of A. inornata, one of its bisexual ancestors. © 2016. Published by The Company of Biologists Ltd.

  16. [Study of allelic polymorphism of (GATA)n-containing loci in parthenogenetic lizards Darevskia unisexualis (Lacertidae)].

    Science.gov (United States)

    Korchagin, V I; Martirosian, I A; Omel'chenko, A V; Darevskiĭ, I S; Ryskov, A P; Tokarskaia, O N

    2004-10-01

    The genesis of mini- and microsatellite loci, which is under extensive study in humans and some other bisexual species, have been virtually overlooked in species with clonal mode of reproduction. Earlier, using multilocus DNA fingerprinting, we have examined variability of some mini- and microsatellite DNA markers in parthenogenetic lizards from the genus Darevskia. In particular, mutant (GATA)n-restrictive DNA fragments were found in Darevskia unisexualis. In the present study, we examined intraspecific polymorphism of three cloned loci of D. unisexualis--Du323, Du215, and Du281--containing (GATA)7GAT(GATA)2, GAT(GATA)9, and (GATA)10TA(GATA) microsatellite clusters, respectively. Different levels of intrapopulation and interpopulation variability of these loci were found. Locus Du281 showed the highest polymorphism--six allelic variants (in the sample of 68 DNA specimens). Three alleles were found for locus Du215. The Du325 locus was electrophoretically invariant. The primers chosen for loci Du323, Du215, and Du281 were also used for PCR analysis of homologous loci in two presumptive parental bisexual species, D. valentini and D. nairensis. The PCR products of the corresponding loci of the parental species had approximately the same size (approximately 200 bp) as their counterparts in D. unisexualis, but the polymorphism levels of the paternal, maternal, and hybrid species were shown to be somewhat different. These data on the structure of the D. unisexualis loci provide a possibility to study genetic diversity in the parthenogenetic species D. unisexualis and other related unisexual and bisexual species of this genus, which can provide new information on the origin of parthenogenetic species and on the phylogenetic relationships in the genus Darevskia. These data can also be used for resolving problems of marking the lizard genome, which is still poorly studied.

  17. DNA damage and micronuclei in parthenogenetic and bisexual Darevskia rock lizards from the areas with different levels of soil pollution.

    Science.gov (United States)

    Simonyan, Anna; Hovhannisyan, Galina; Sargsyan, Anzhela; Arakelyan, Marine; Minasyan, Seyran; Aroutiounian, Rouben

    2018-06-15

    Natural species are widely used as indicator organisms to estimate of the impact of environmental pollution. Here we present the results of first study of a reliability of parthenogenetic Darevskia аrmeniaca and bisexual Darevskia raddei rock lizards as sentinels for monitoring of environmental genotoxicity. The comet assay and micronucleus test were applied to the lizards sampled in six areas in Armenia and Artsakh with different levels of soil contamination. The results obtained showed a clear relationship between the pollution level of lizards' habitats and the frequency of DNA damage in the comet assay. Low baseline frequency of micronuclei in D. аrmeniaca and D. raddei, however, makes this parameter ineffective for environmental genotoxicity evaluation. The parthenogenetic lizards D. аrmeniaca showed higher sensitivity toward genotoxic pollutions compared with bisexual D. raddei living in the same environment. The correlations between soil content of heavy metals Cr, Cu, Zn, Mo, Pb and DNA damage in D. аrmeniaca and between Cu, As, Mo, Pb and DNA damage in D. raddei were revealed. Overall, the lizards D. raddei and D. аrmeniaca appeared to be sensitive species in detecting soil pollution in natural environment. The application of the comet assay in Darevskia lizard species can be considered as a more appropriate method than a micronucleus test. The use of parthenogenetic lizards D. аrmeniaca as bioindicator will permit to assess the environmental genotoxicity independent of the genetic polymorphism of bisexual species. Copyright © 2018. Published by Elsevier Inc.

  18. Optimal developmental stage for vitrification of parthenogenetically activated porcine embryos

    DEFF Research Database (Denmark)

    Li, Rong; Li, Juan; Kragh, Peter

    2012-01-01

    The objective of this experiment was to determine the optimal developmental stage to vitrify in-vitro cultured porcine parthenogenetically activated (PA) embryos. Embryos were vitrified by Cryotop on Day 4, 5 or 6 after oocyte activation (Day 0), and immediately after warming they were either time...

  19. Changes in Parthenogenetic Imprinting Patterns during Reprogramming by Cell Fusion.

    Directory of Open Access Journals (Sweden)

    Hyun Sik Jang

    Full Text Available Differentiated somatic cells can be reprogrammed into the pluripotent state by cell-cell fusion. In the pluripotent state, reprogrammed cells may then self-renew and differentiate into all three germ layers. Fusion-induced reprogramming also epigenetically modifies the somatic cell genome through DNA demethylation, X chromosome reactivation, and histone modification. In this study, we investigated whether fusion with embryonic stem cells (ESCs also reprograms genomic imprinting patterns in somatic cells. In particular, we examined imprinting changes in parthenogenetic neural stem cells fused with biparental ESCs, as well as in biparental neural stem cells fused with parthenogenetic ESCs. The resulting hybrid cells expressed the pluripotency markers Oct4 and Nanog. In addition, methylation of several imprinted genes except Peg3 was comparable between hybrid cells and ESCs. This finding indicates that reprogramming by cell fusion does not necessarily reverse the status of all imprinted genes to the state of pluripotent fusion partner.

  20. Developmental success, stability, and plasticity in closely related parthenogenetic and sexual lizards (Heteronotia, Gekkonidae).

    Science.gov (United States)

    Kearney, Michael; Shine, Richard

    2004-07-01

    was the case for their sexual relatives. Thus, the evolution of asexual reproduction in this species complex has modified both mean hatchling viability and the norms of reaction linking hatchling phenotypes to incubation temperature. Discussions on the reasons why parthenogenetic organisms are scarce in nature should take into account interactive effects such as these; future work could usefully try to tease apart the roles of parthenogenesis, its hybrid origin (and thus effects on ploidy and heterozygosity, etc.), and clonal selection in generating these divergent embryonic responses.

  1. Genome analysis of Diploscapter coronatus: insights into molecular peculiarities of a nematode with parthenogenetic reproduction.

    Science.gov (United States)

    Hiraki, Hideaki; Kagoshima, Hiroshi; Kraus, Christopher; Schiffer, Philipp H; Ueta, Yumiko; Kroiher, Michael; Schierenberg, Einhard; Kohara, Yuji

    2017-06-24

    Sexual reproduction involving the fusion of egg and sperm is prevailing among eukaryotes. In contrast, the nematode Diploscapter coronatus, a close relative of the model Caenorhabditis elegans, reproduces parthenogenetically. Neither males nor sperm have been observed and some steps of meiosis are apparently skipped in this species. To uncover the genomic changes associated with the evolution of parthenogenesis in this nematode, we carried out a genome analysis. We obtained a 170 Mbp draft genome in only 511 scaffolds with a N 50 length of 1 Mbp. Nearly 90% of these scaffolds constitute homologous pairs with a 5.7% heterozygosity on average and inversions and translocations, meaning that the 170 Mbp sequences correspond to the diploid genome. Fluorescent staining shows that the D. coronatus genome consists of two chromosomes (2n = 2). In our genome annotation, we found orthologs of 59% of the C. elegans genes. However, a number of genes were missing or very divergent. These include genes involved in sex determination (e.g. xol-1, tra-2) and meiosis (e.g. the kleisins rec-8 and coh-3/4) giving a possible explanation for the absence of males and the second meiotic division. The high degree of heterozygosity allowed us to analyze the expression level of individual alleles. Most of the homologous pairs show very similar expression levels but others exhibit a 2-5-fold difference. Our high-quality draft genome of D. coronatus reveals the peculiarities of the genome of parthenogenesis and provides some clues to the genetic basis for parthenogenetic reproduction. This draft genome should be the basis to elucidate fundamental questions related to parthenogenesis such as its origin and mechanisms through comparative analyses with other nematodes. Furthermore, being the closest outgroup to the genus Caenorhabditis, the draft genome will help to disclose many idiosyncrasies of the model C. elegans and its congeners in future studies.

  2. Increased capacity for sustained locomotion at low temperature in parthenogenetic geckos of hybrid origin.

    Science.gov (United States)

    Kearney, Michael; Wahl, Rebecca; Autumn, Kellar

    2005-01-01

    The evolution of parthenogenesis is typically associated with hybridization and polyploidy. These correlates of parthenogenesis may have important physiological consequences that need be taken into account in understanding the relative merits of sexual and parthenogenetic reproduction. We compared the thermal sensitivity of aerobically sustained locomotion in hybrid/triploid parthenogenetic races of the gecko Heteronotia binoei and their diploid sexual progenitors. Endurance times at low temperature (10 degrees , 12.5 degrees , and 15 degrees C, 0.05 km h(-1)) were significantly greater in parthenogenetic females than in sexual females. Comparison of oxygen consumption rates during sustained locomotion at increasing speeds (0.05, 0.10, 0.15, 0.20, 0.25, and 0.30 km h(-1), 25 degrees C) indicated that parthenogenetic lizards have higher maximum oxygen consumption rates and maximum aerobic speeds than do female sexual geckos. In addition, parthenogenetic geckos showed greater levels of voluntary activity at 15 degrees C than did sexual geckos, although this pattern appears strongest in comparison to male sexual forms. Parthenogenetic lineages of Heteronotia thus have an advantage over sexual lineages in being capable of greater aerobic activity. This result is opposite of that found in prior studies of parthenogenetic teiid lizards (genus Cnemidophorus) and highlights the idiosyncratic nature of phenotypic evolution in parthenogens of hybrid origin.

  3. Clonal diversity and clone formation in the parthenogenetic Caucasian rock Lizard Darevskia dahli [corrected].

    Science.gov (United States)

    Vergun, Andrey A; Martirosyan, Irena A; Semyenova, Seraphima K; Omelchenko, Andrey V; Petrosyan, Varos G; Lazebny, Oleg E; Tokarskaya, Olga N; Korchagin, Vitaly I; Ryskov, Alexey P

    2014-01-01

    The all-female Caucasian rock lizard species Darevskia dahli and other parthenogenetic species of this genus reproduce normally via true parthenogenesis. Previously, the genetic diversity of this species was analyzed using allozymes, mitochondrial DNA, and DNA fingerprint markers. In the present study, variation at three microsatellite loci was studied in 111 specimens of D. dahli from five populations from Armenia, and new information regarding clonal diversity and clone formation in D. dahli was obtained that suggests a multiple hybridization origin. All individuals but one were heterozygous at the loci studied. Based on specific allele combinations, 11 genotypes were identified among the individuals studied. Individuals with the same genotypes formed distinct clonal lineages: one major clone was represented by 72 individuals, an intermediate clone was represented by 21 individuals, and nine other clones were rare and represented by one or several individuals. A new approach based on the detection and comparison of genotype-specific markers formed by combinations of parental-specific markers was developed and used to identify at least three hybridization founder events that resulted in the initial formation of one major and two rare clones. All other clones, including the intermediate and seven rare clones, probably arose through postformation microsatellite mutations of the major clone. This approach can be used to identify hybridization founder events and to study clone formation in other unisexual taxa.

  4. Aseptic minimum volume vitrification technique for porcine parthenogenetically activated blastocyst.

    Science.gov (United States)

    Lin, Lin; Yu, Yutao; Zhang, Xiuqing; Yang, Huanming; Bolund, Lars; Callesen, Henrik; Vajta, Gábor

    2011-01-01

    Minimum volume vitrification may provide extremely high cooling and warming rates if the sample and the surrounding medium contacts directly with the respective liquid nitrogen and warming medium. However, this direct contact may result in microbial contamination. In this work, an earlier aseptic technique was applied for minimum volume vitrification. After equilibration, samples were loaded on a plastic film, immersed rapidly into factory derived, filter-sterilized liquid nitrogen, and sealed into sterile, pre-cooled straws. At warming, the straw was cut, the filmstrip was immersed into a 39 degree C warming medium, and the sample was stepwise rehydrated. Cryosurvival rates of porcine blastocysts produced by parthenogenetical activation did not differ from control, vitrified blastocysts with Cryotop. This approach can be used for minimum volume vitrification methods and may be suitable to overcome the biological dangers and legal restrictions that hamper the application of open vitrification techniques.

  5. Coping with living in the soil: : the genome of the parthenogenetic springtail Folsomia candida

    NARCIS (Netherlands)

    Faddeeva-Vakhrusheva, Anna; Kraaijeveld, Ken; Derks, Martijn F L; Anvar, Seyed Yahya; Agamennone, Valeria; Suring, Wouter; Kampfraath, Andries A.; Ellers, Jacintha; Le Ngoc, Giang; van Gestel, Cornelis A.M.; Mariën, Janine; Smit, Sandra; van Straalen, Nico M.; Roelofs, Dick

    2017-01-01

    BACKGROUND: Folsomia candida is a model in soil biology, belonging to the family of Isotomidae, subclass Collembola. It reproduces parthenogenetically in the presence of Wolbachia, and exhibits remarkable physiological adaptations to stress. To better understand these features and adaptations to

  6. Effect of zona pellucida on porcine parthenogenetically activated embryos

    DEFF Research Database (Denmark)

    Li, Rong; Liu, Ying; Li, Juan

    2011-01-01

    μg mL–1 cytochalasin B and 10 μg mL–1 cycloheximide in PZM-3 medium for 4 h. ZP was removed by 3.3 mg mL–1 pronase. Both zona-intact (PAZI) and zona-free (PAZF) embryos were cultured individually for 6 days either in time-lapse incubator (Embryoscope D, Unisense A/S, Aarhus, Denmark) for 15-min......). The timing of morulae was recorded when they completed compaction. Good blastocysts were defined when they expanded to 1.5 times larger than oocytes and formed regular blastocoel cavity with uniform colour and distribution of cells. Timing data were analysed by Student's t-test, while development rates....... 22, 234). In the present study, we expanded this study to include also the timing of early development and the resulting quality and robustness (for vitrification) of porcine PA embryos. Parthenogenetic activation was made first by an electric pulse (1.26 kV cm–1, 80 μs) and then by incubation with 5...

  7. Lower fecundity in parthenogenetic geckos than sexual relatives in the Australian arid zone.

    Science.gov (United States)

    Kearney, M; Shine, R

    2005-05-01

    Theoretical models of the advantage of sexual reproduction typically assume that reproductive output is equal in sexual and parthenogenetic females. We tested this assumption by comparing fecundity between parthenogenetic and sexual races of gekkonid lizards in the Heteronotia binoei complex, collected across a 1200 km latitudinal gradient through the Australian arid zone. Under laboratory conditions, parthenogenetic geckos had approximately 30% lower fecundity when compared with their sexual progenitors, irrespective of body size. Reflecting clutch-size constraints in gekkonids, this fecundity difference was mainly because of fewer clutches over a shorter period. When parthenogens were compared more broadly with all coexisting sexual races across the latitudinal gradient, parthenogens had lower fecundity than sexuals only when corrected for body size. Differences in fecundity between parthenogens and coexisting sexual races depended on which sexual race was considered. There was no significant relationship between fecundity and parasite (mite) load, despite significantly higher mite loads in parthenogens than in sexual races.

  8. Population structure of an invasive parthenogenetic gastropod in coastal lakes and estuaries of northern KwaZulu-Natal, South Africa.

    Directory of Open Access Journals (Sweden)

    Nelson A F Miranda

    Full Text Available BACKGROUND: Estuaries and coastal lakes receive little attention despite being heavily invaded by non-indigenous invasive species (NIS. In these situations, studies of population dynamics in invaded habitats can provide valuable insights into how NIS interact with new environments. Tarebia granifera is a prosobranch gastropod from south-east Asia which has invaded other sub-tropical parts of the world. This study addresses whether a small number of key environmental factors influences gastropod communities, and specifically how the population density and size structure of T. granifera were influenced by environmental change in estuaries and coastal lakes in southern Africa. METHODOLOGY/PRINCIPAL FINDINGS: T. granifera's density, number of brooded juveniles and size structure were measured at the St. Lucia Estuary, Mgobozeleni Estuary, Lake Sibaya and Lake Nhlange. Size structure was classified according to shell height (SH. All dissected individuals were found to be female and free from trematode infection. Salinity, water depth, temperature, and pH were the main factors correlated with population density of gastropod communities. T. granifera often reached densities well over 1000 ind. m(-2, displacing indigenous gastropods and becoming a dominant component of the benthic community. T. granifera successfully invaded estuaries despite frequent exposure to high salinity and desiccation, which could together eliminate >97% of the population. The persistence of T. granifera was ensured due to its high fecundity and the environmental tolerance of large adults (20-30 mm SH which carried an average of 158±12.8 SD brooded juveniles. Repeat introductions were not essential for the success of this parthenogenetic NIS. CONCLUSION/SIGNIFICANCE: There is a need for a broader study on the reproductive biology of T. granifera (including the previously overlooked "brood pouch ecology", which affects population dynamics and may be relevant to other

  9. The relationship between reproductive state and "sexually" dimorphic brain areas in sexually reproducing and parthenogenetic whiptail lizards.

    Science.gov (United States)

    Wade, J; Crews, D

    1991-07-22

    The anterior hypothalamus-preoptic area and ventromedial hypothalamus are sexually dimorphic in the reproductively active whiptail lizard Cnemidophorus inornatus. The anterior hypothalamus-preoptic area, which is involved in the control of male-typical copulatory behaviors, is larger in males, whereas the ventromedial hypothalamus, which is involved in the control of female-typical receptivity, is larger in females. In the parthenogenetic whiptail lizard C. uniparens, which is a direct descendant of C. inornatus and exhibits both male-like and female-like pseudosexual behaviors, both brain areas are comparable in size to those of female C. inornatus. This study was conducted to determine whether these brain areas change in size in either species or sex during a time of year when these animals are reproductively inactive, or after removal of the gonads. In male C. inornatus both brain areas changed during reproductive inactivity (either seasonally or surgically induced) and became equivalent to the size characteristic of reproductively active female C. inornatus. When corrected for brain size, the anterior hypothalamus-preoptic area was significantly smaller in intact hibernating and castrated males than in intact males from the summer breeding season. Conversely, the ventromedial hypothalamus was significantly larger in intact hibernating and castrated males than in intact males from the summer breeding season. The two brain areas were not significantly different among the groups of female C. inornatus or parthenogenetic C. uniparens. These results suggest that 1) the brain of whiptail lizards may differentiate seasonally and 2) the female state may be a neutral one to which the male brain reverts during reproductive inactivity.

  10. Comparative Study of Biological and Technological Characters in Three Generations of Silkworm Bombyxmori L. Ameiotic, Parthenogenetically Cloned Lines

    OpenAIRE

    Greiss, H.; Vassilieva, J.; Petkov, N.; Petkov, Z.

    2004-01-01

    Purpose: Detect any deviation in biologic and technologic characters of eight ameiotic-parthenogenetically cloned lines of Bombyx mori L. from different origins from a normal sexually reproduced control line in three generations.

  11. Differences in the genetic control of early egg development and reproduction between C. elegans and its parthenogenetic relative D. coronatus.

    Science.gov (United States)

    Kraus, Christopher; Schiffer, Philipp H; Kagoshima, Hiroshi; Hiraki, Hideaki; Vogt, Theresa; Kroiher, Michael; Kohara, Yuji; Schierenberg, Einhard

    2017-01-01

    The free-living nematode Diploscapter coronatus is the closest known relative of Caenorhabditis elegans with parthenogenetic reproduction. It shows several developmental idiosyncracies, for example concerning the mode of reproduction, embryonic axis formation and early cleavage pattern (Lahl et al. in Int J Dev Biol 50:393-397, 2006). Our recent genome analysis (Hiraki et al. in BMC Genomics 18:478, 2017) provides a solid foundation to better understand the molecular basis of developmental idiosyncrasies in this species in an evolutionary context by comparison with selected other nematodes. Our genomic data also yielded indications for the view that D. coronatus is a product of interspecies hybridization. In a genomic comparison between D. coronatus , C. elegans , other representatives of the genus Caenorhabditis and the more distantly related Pristionchus pacificus and Panagrellus redivivus , certain genes required for central developmental processes in C. elegans like control of meiosis and establishment of embryonic polarity were found to be restricted to the genus Caenorhabditis . The mRNA content of early D. coronatus embryos was sequenced and compared with similar stages in C. elegans and Ascaris suum . We identified 350 gene families transcribed in the early embryo of D. coronatus but not in the other two nematodes. Looking at individual genes transcribed early in D. coronatus but not in C. elegans and A. suum , we found that orthologs of most of these are present in the genomes of the latter species as well, suggesting heterochronic shifts with respect to expression behavior. Considerable genomic heterozygosity and allelic divergence lend further support to the view that D. coronatus may be the result of an interspecies hybridization. Expression analysis of early acting single-copy genes yields no indication for silencing of one parental genome. Our comparative cellular and molecular studies support the view that the genus Caenorhabditis differs

  12. Differences in the genetic control of early egg development and reproduction between C. elegans and its parthenogenetic relative D. coronatus

    Directory of Open Access Journals (Sweden)

    Christopher Kraus

    2017-10-01

    Full Text Available Abstract Background The free-living nematode Diploscapter coronatus is the closest known relative of Caenorhabditis elegans with parthenogenetic reproduction. It shows several developmental idiosyncracies, for example concerning the mode of reproduction, embryonic axis formation and early cleavage pattern (Lahl et al. in Int J Dev Biol 50:393–397, 2006. Our recent genome analysis (Hiraki et al. in BMC Genomics 18:478, 2017 provides a solid foundation to better understand the molecular basis of developmental idiosyncrasies in this species in an evolutionary context by comparison with selected other nematodes. Our genomic data also yielded indications for the view that D. coronatus is a product of interspecies hybridization. Results In a genomic comparison between D. coronatus, C. elegans, other representatives of the genus Caenorhabditis and the more distantly related Pristionchus pacificus and Panagrellus redivivus, certain genes required for central developmental processes in C. elegans like control of meiosis and establishment of embryonic polarity were found to be restricted to the genus Caenorhabditis. The mRNA content of early D. coronatus embryos was sequenced and compared with similar stages in C. elegans and Ascaris suum. We identified 350 gene families transcribed in the early embryo of D. coronatus but not in the other two nematodes. Looking at individual genes transcribed early in D. coronatus but not in C. elegans and A. suum, we found that orthologs of most of these are present in the genomes of the latter species as well, suggesting heterochronic shifts with respect to expression behavior. Considerable genomic heterozygosity and allelic divergence lend further support to the view that D. coronatus may be the result of an interspecies hybridization. Expression analysis of early acting single-copy genes yields no indication for silencing of one parental genome. Conclusions Our comparative cellular and molecular studies support the

  13. Phylogeography of competing sexual and parthenogenetic forms of a freshwater flatworm: patterns and explanations

    Directory of Open Access Journals (Sweden)

    Carranza Salvador

    2003-11-01

    Full Text Available Abstract Background Models of the maintenance of sex predict that one reproductive strategy, sexual or parthenogenetic, should outcompete the other. Distribution patterns may reflect the outcome of this competition as well as the effect of chance and historical events. We review the distribution data of sexual and parthenogenetic biotypes of the planarian Schmidtea polychroa. Results S. polychroa lives in allopatry or sympatry across Europe except for Central and North-Western Europe, where sexual individuals have never been reported. A phylogenetic relationship between 36 populations based on a 385 bp fragment of the mitochondrial cytochrome oxidase I gene revealed that haplotypes were often similar over large geographic distances. In North Italian lakes, however, diversity was extreme, with sequence differences of up to 5% within the same lake in both sexuals and parthenogens. Mixed populations showed "endemic" parthenogenetic lineages that presumably originated from coexisting sexuals, and distantly related ones that probably result from colonization by parthenogens independent from sexuals. Conclusions Parthenogens originated repeatedly from sexuals, mainly in Italy, but the same may apply to other Mediterranean regions (Spain, Greece. The degree of divergence between populations suggests that S. polychroa survived the ice ages in separate ice-free areas in Central, Eastern and Southern Europe and re-colonised Europe after the retreat of the major glaciers. Combining these results with those based on nuclear markers, the data suggest that repeated hybridisation between sexuals and parthenogenetic lineages in mixed populations maintains high levels of genetic diversity in parthenogens. This can explain why parthenogens persist in populations that were originally sexual. Exclusive parthenogenesis in central and western populations suggests better colonisation capacity, possibly because of inbreeding costs as well as hybridisation of sexuals

  14. Nematode assemblages associated with the parthenogenetic lizard Ameivula nativo in six restinga areas along the eastern coast of Brazil.

    Science.gov (United States)

    Menezes, V A; Mascarenhas, J C; Vrcibradic, D; Rocha, C F D

    2017-10-04

    We surveyed the nematode assemblages associated with populations of the parthenogenetic whiptail lizard Ameivula nativo from six coastal restinga areas in eastern Brazil: Setiba, Comboios and Guriri (State of Espirito Santo) and Guaratiba, Prado and Maraú (State of Bahia). A total of five nematode species (Physaloptera retusa, Physalopteroides venancioi, Skrjabinelazia intermedia, Subulura lacertilia and Parapharyngodon sp.) were recorded from the six different populations of A. nativo. There was considerable variation in overall prevalence of infection (1-42%) among study sites, but geographical distance among areas did not influence similarity in the composition of nematode assemblages. Overall intensity of infection was not affected by lizard body size and did not seem to affect host body condition, based on pooled data of all populations. The studied populations of the unisexual A. nativo had relatively low prevalences and intensities of infection compared to some bisexual congeners and to sympatric lizards from other families for which such data are available. We believe that the low richness of the nematode fauna associated with A. nativo, both locally and regionally, may reflect its narrow geographic distribution and the low diversity of habitats it occupies.

  15. Effect of a High Dose of Three Antibiotics on the Reproduction of a Parthenogenetic Strain of Folsomia candida (Isotomidae: Collembola)

    DEFF Research Database (Denmark)

    Giordano, R.; Weber, E; Waite, J

    2010-01-01

    Folsomia candida Willem (Isotomidae: Collembola) is an edaphic parthenogenetic species commonly used in ecotoxicity studies. We exposed F. candida to a high dose of three antibiotics, tylosin, ampicillin, and oxytetracycline, that target different bacterial groups. Possible toxic effects were...... assessed through egg production, hatching, and body size. All three antibiotics caused toxic effects. Treatment with oxytetracycline proved the most toxic. This group showed the smallest body size and lowest number of eggs laid, likely the result of a combination of antibiotic toxicity and avoidance...... of the antibiotic spiked food. Active toxin avoidance by F. candida in toxicological assays may play a role in minimizing their exposure to toxic compounds. Despite the administration of high doses of oxytetracycline, F. candida individuals remained infected with the intracellular bacteria Wolbachia indicating...

  16. Genetic homogeneity between two populations of the parthenogenetic lizard Aspidoscelis cozumela Homogeneidad genética entre dos poblaciones de la lagartija partenogenética Aspidoscelis cozumela

    Directory of Open Access Journals (Sweden)

    Norma L. Manríquez-Morán

    2008-12-01

    Full Text Available We used skin-grafting to assess the genetic variability between 2 populations of the parthenogenetic lizard Aspidoscelis cozumela. We transplanted 238 skin fragments among individuals of 2 coastal populations at Cozumel Island. Grafts belonging to individuals that survive more than 60 days suggested genetic homogeneity between both populations, consistent with the existence of only 1 clone within this unisexual species.Se utilizó el método de transplantes de piel para evaluar la variabilidad genética entre 2 poblaciones de la lagartija partenogenética Aspidoscelis cozumela. Se transplantaron 238 fragmentos de piel entre individuos de 2 poblaciones costeras de Isla Cozumel. Los transplantes pertenecientes a individuos que vivieron más de 60 días, mostraron homogeneidad genética entre ambas poblaciones, lo cual sugiere la existencia de 1 sólo clon dentro de esta especie unisexual.

  17. Paternal inheritance of B chromosomes in a parthenogenetic hermaphrodite

    NARCIS (Netherlands)

    Beukeboom, Leo W.; Seif, Miriam; Mettenmeyer, Thomas; Plowman, Amy B.; Michiels, Nicolaas K.

    1996-01-01

    B chromosomes are dispensable elements extra to the standard (A) chromosome complement. They have been described from many sexually reproducing species where they often exploit meiosis to accumulate from one generation to the next. Polycelis nigra is a simultaneously hermaphroditic flatworm that can

  18. Parallel origins of duplications and the formation of pseudogenes in mitochondrial DNA from parthenogenetic lizards (Heteronotia binoei; Gekkonidae).

    Science.gov (United States)

    Zevering, C E; Moritz, C; Heideman, A; Sturm, R A

    1991-11-01

    Analysis of mitochondrial DNAs (mtDNAs) from parthenogenetic lizards of the Heteronotia binoei complex with restriction enzymes revealed an approximately 5-kb addition present in all 77 individuals. Cleavage site mapping suggested the presence of a direct tandem duplication spanning the 16S and 12S rRNA genes, the control region and most, if not all, of the gene for the subunit 1 of NADH dehydrogenase (ND1). The location of the duplication was confirmed by Southern hybridization. A restriction enzyme survey provided evidence for modifications to each copy of the duplicated sequence, including four large deletions. Each gene affected by a deletion was complemented by an intact version in the other copy of the sequence, although for one gene the functional copy was heteroplasmic for another deletion. Sequencing of a fragment from one copy of the duplication which encompassed the tRNA(leu)(UUR) and parts of the 16S rRNA and ND1 genes, revealed mutations expected to disrupt function. Thus, evolution subsequent to the duplication event has resulted in mitochondrial pseudogenes. The presence of duplications in all of these parthenogens, but not among representatives of their maternal sexual ancestors, suggests that the duplications arose in the parthenogenetic form. This provides the second instance in H. binoei of mtDNA duplication associated with the transition from sexual to parthenogenetic reproduction. The increased incidence of duplications in parthenogenetic lizards may be caused by errors in mtDNA replication due to either polyploidy or hybridity of their nuclear genomes.

  19. Comparative study of biological and technological characters in three generations of silkworm Bombyx mori L. ameiotic, parthenogenetically cloned lines.

    Science.gov (United States)

    Greiss, H; Vassilieva, J; Petkov, N; Petkov, Z

    2004-11-01

    Detect any deviation in biologic and technologic characters of eight ameiotic-parthenogenetically cloned lines of Bombyx mori L. from different origins from a normal sexually reproduced control line in three generations. Comparative study of the three generations was conducted in SES, Vratza, unit of the National Center for Agrarian Sciences of Bulgaria after fixing all environmental rearing conditions. The ameiotic-parthen-clones displayed good parthenogenetic development, although total hatchability was significantly less than the sexually reproducing control populations. Survival rates between clones and control were not significantly different. All clones displayed significantly longer larval periods. Slight decline in second generation, and a steeper one in the third generation were observed for all eight cloned lines in cocoon weight, shell weight, and shell ratio and these differences were statistically significant. Cocoon yield was significantly lower than the control throughout the three generations. Our parthen-cloning method has a high rate of success in comparison to other cloning methods, the cloned progeny populations although were weaker technologically (cocoon weight, shell weight, and shell ratio), the biological characters (parthenogenetic development and survival rate) were not compromised. Further study is needed to determine the thermal needs of the cloned embryos and metabolic rate of all stages.

  20. Comparison of Teratoma Formation between Embryonic Stem Cells and Parthenogenetic Embryonic Stem Cells by Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Hongyan Tao

    2018-01-01

    Full Text Available With their properties of self-renewal and differentiation, embryonic stem (ES cells hold great promises for regenerative therapy. However, teratoma formation and ethical concerns of ES cells may restrict their potential clinical applications. Currently, parthenogenetic embryonic stem (pES cells have attracted the interest of researchers for its self-renewing and pluripotent differentiation while eliciting less ethic concerns. In this study, we established a model with ES and pES cells both stably transfected with a double-fusion reporter gene containing renilla luciferase (Rluc and red fluorescent protein (RFP to analyze the mechanisms of teratoma formation. Transgenic Vegfr2-luc mouse, which expresses firefly luciferase (Fluc under the promoter of vascular endothelial growth factor receptor 2 (Vegfr2-luc, was used to trace the growth of new blood vessel recruited by transplanted cells. Bioluminescence imaging (BLI of Rluc/Fluc provides an effective tool in estimating the growth and angiogenesis of teratoma in vivo. We found that the tumorigenesis and angiogenesis capacity of ES cells were higher than those of pES cells, in which VEGF/VEGFR2 signal pathway plays an important role. In conclusion, pES cells have the decreased potential of teratoma formation but meanwhile have similar differentiating capacity compared with ES cells. These data demonstrate that pES cells provide an alternative source for ES cells with the risk reduction of teratoma formation and without ethical controversy.

  1. Improved parthenogenetic development of vitrified-warmed bovine oocytes activated with 9% ethanol plus 6-DMAP

    DEFF Research Database (Denmark)

    Hou, Y -p; Liu, Ying; Dai, Y -p

    2009-01-01

    The objective was to compare various activation protocols on developmental potential of vitrified bovine oocytes. Bovine oocytes matured in vitro for 23 h were vitrified with EDFSF30 in open pulled straws. After warming, they were cultured in vitro for 1 h, followed by parthenogenetic activation....... Vitrified-warmed oocytes had a morphologically normal rate similar to that of controls (nonvitrified oocytes cultured in vitro for 24 h; 98.6% vs. 100%, P > 0.05). When vitrified-warmed oocytes were first activated with 7% ethanol for 5 min and then incubated in 6-dimethylaminopurin (6-DMAP) for 4 h...... (for 5 min) or in combination with 6-DMAP (4 h) was used to activate vitrified-warmed oocytes, cleavage rates ranged from 22.3% to 61.1% and blastocyst rates ranged from 1.1% to 30.6%. These rates were optimized when oocytes were treated with 9% ethanol plus 6-DMAP; this was verified in experiments...

  2. Effects of gamma irradiation of pollen on parthenogenetic haploid production in muskmelon (Cucumis melo L.)

    International Nuclear Information System (INIS)

    Cuny, F.; Grotte, M.; Dumas de Vaulx, R.; Rieu, A.

    1993-01-01

    The effects of increasing gamma ray exposures on muskmelon pollen of the Védrantais genotype were evaluated after autofertilization and hybridization with the F1.G1 genotype. Regardless of doses of between 0.15 and 1.6 kGy, fruit set and number of seeds per fruit were comparable to those of the control. The pollen tube from pollen irradiated with up to 2.5 kGy grew in styles and reached the ovules. When pollen was cultivated in vitro, relatively high doses of irradiation (1.6 kGy) were needed to reduce the level of germination. Radiation-induced changes in the generative nucleus led to the formation of two chromosomally unbalanced sperm cells (as indicated by the appearance of morphological dimorphism) which induced parthenogenetic development of the egg to form a haploid embryo. Haploid embryo production by gamma-irradiated pollen was genotype dependent. For exposures of between 0.15 and 2.5 kGy, the production of embryos was the same, about 3.4%; a maximum of 70% of these embryos placed in a specific culture medium produced haploid plants. The ploidy of the plantlets in vitro was determined by flow cytometry. No aneuploidy was detected. All resulting plants exhibited normal phenotypes. (author) [fr

  3. Ways Out of the Patenting Prohibition? Human Parthenogenetic and Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Schickl, Hannah; Braun, Matthias; Dabrock, Peter

    2017-06-01

    According to the judgement of the European Court of Justice in 2014, human parthenogenetic stem cells are excluded from the patenting prohibition of procedures based on hESC by the European Biopatent Directive, because human parthenotes are not human embryos. This article is based on the thesis that in light of the technological advances in the field of stem cell research, the attribution of the term 'human embryo' to certain entities on a descriptive level as well as the attribution of a normative protection status to certain entities based on the criterion of totipotency, are becoming increasingly unclear. The example of human parthenotes in particular demonstrates that totipotency is not at all a necessary condition for the attribution of the term 'human embryo'. Furthermore, the example of hiPSC and somatic cells particularly shows that totipotency is also not a sufficient condition for the attribution of a normative protection status to certain entities. Therefore, it is not a suitable criterion for distinguishing between human embryos worthy of protection and human non-embryos not worthy of protection. Consequently, this conclusion has repercussions for the patenting question. The strict delineation between an ethically problematic commercial use of human embryos and the concomitant patenting prohibition of hESC-based procedures and an ethically unproblematic commercial use of human non-embryos and the therefore either unrestrictedly permitted (cf. human parthenotes) or even unregulated (cf. hiPSC) patenting of procedures based on these alleged alternatives becomes increasingly blurred. © 2017 The Authors. Bioethics Published by John Wiley & Sons Ltd.

  4. Development capacity of pre- and postpubertal pig oocytes evaluated by somatic cell nuclear transfer and parthenogenetic activation

    DEFF Research Database (Denmark)

    Skovsgaard, Hanne; Li, Rong; Liu, Ying

    2013-01-01

    Most of the porcine oocytes used for in vitro studies are collected from gilts. Our aims were to study development capacity of gilt v. sow oocytes (pre- and postpubertal respectively) using 2 techniques illustrating development competence [parthenogenetic activation (PA) and somatic cell nuclear...... transfer (SCNT)], and to describe a simple method to select the most competent oocytes. Inside-ZP diameter of in vitro-matured gilt oocytes was measured (µm; small ≤110; medium >110; large ≥120). Gilt and sow oocytes were morphologically grouped as good (even cytoplasm, smooth cell membrane, visible...

  5. The optimal period of Ca-EDTA treatment for parthenogenetic activation of porcine oocytes during maturation culture

    OpenAIRE

    MORITA, Yasuhiro; TANIGUCHI, Masayasu; TANIHARA, Fuminori; ITO, Aya; NAMULA, Zhao; DO, Lanh Thi Kim; TAKAGI, Mitsuhiro; TAKEMOTO, Tatsuya; OTOI, Takeshige

    2016-01-01

    The changes triggered by sperm-induced activation of oocytes, which are required for normal oocyte development, can be mediated by other agents, thereby inducing the parthenogenesis. In this study, we exposed porcine oocytes to 1 mM Ca-EDTA, a metal-ion chelator, at various intervals during 48 hr of in vitro maturation to determine the optimum period of Ca-EDTA treatment for parthenogenetic activation. When the oocytes were cultured with or without Ca-EDTA from 36 hr (post-12), 24 hr (post-24...

  6. Laboratory synthesis of an independently reproducing vertebrate species.

    Science.gov (United States)

    Lutes, Aracely A; Baumann, Diana P; Neaves, William B; Baumann, Peter

    2011-06-14

    Speciation in animals commonly involves an extrinsic barrier to genetic exchange followed by the accumulation of sufficient genetic variation to impede subsequent productive interbreeding. All-female species of whiptail lizards, which originated by interspecific hybridization between sexual progenitors, are an exception to this rule. Here, the arising species instantaneously acquires a novel genotype combining distinctive alleles from two different species, and reproduction by parthenogenesis constitutes an effective intrinsic barrier to genetic exchange. Fertilization of diploid parthenogenetic females by males of sexual species has produced several triploid species, but these instantaneous speciation events have neither been observed in nature nor have they been reconstituted in the laboratory. Here we report the generation of four self-sustaining clonal lineages of a tetraploid species resulting from fertilization of triploid oocytes from a parthenogenetic Aspidoscelis exsanguis with haploid sperm from Aspidoscelis inornata. Molecular and cytological analysis confirmed the genetic identity of the hybrids and revealed that the females retain the capability of parthenogenetic reproduction characteristic of their triploid mothers. The tetraploid females have established self-perpetuating clonal lineages which are now in the third generation. Our results confirm the hypothesis that secondary hybridization events can lead to asexual lineages of increased ploidy when favorable combinations of parental genomes are assembled. We anticipate that these animals will be a critical tool in understanding the mechanisms underlying the origin and subsequent evolution of asexual amniotes.

  7. Sexual characteristics and spermatogenesis in males of the parthenogenetic gecko Lepidodactylus lugubris (Reptilia, Gekkonidae).

    Science.gov (United States)

    Röll, Beate; von Düring, Monika U G

    2008-01-01

    Obligately parthenogenetic lizards usually are all-female populations of hybrids producing diploid oocytes by premeiotic endomitosis and quasi-normal meiosis. In an all-female strain of the gekkonid lizard Lepidodactylus lugubris several phenotypic males arose spontaneously. The sexual characteristics of these males were studied using light and electron microscopy and compared with normal males of the bisexual genus Lygodactylus. Emphasis was layed on morphology of seminiferous tubules, occurrence of spermatogenic stages and ultrastructure of spermatozoa. The phenotypic males possessed preanal pores filled with secretions and a sexual nephric segment which were exactly the same as in normal, reproductively active males. In the testes, density and morphology of non-spermatogenic cell types, the Leydig and Sertoli cells, indicate a normal production of testicular testosterone and a normal function of the blood-testis barrier, respectively. Both in the normal and the phenotypic males, all meiotic cell types of spermatogenesis can be recognised in the seminiferous tubules and are apparently identical, indicating a normal meiosis without impairment in the phenotypic males. In contrast, the differentiation process of spermatids is markedly disturbed in the phenotypic males of L. lugubris. In the normal male, spermiogenesis results in mature spermatids and spermatozoa with small elongated nuclei, an acrosomal complex, and a flagellar tail possessing one axoneme. Spermatozoa fill both the lumen of most seminiferous tubules and the lumina of ductus epididymidis and ductus deferens. In the phenotypic male, spermiogenesis results in seemingly normal spermatids and in spermatozoa with large, non-elongated, deformed nuclei and/or irregular tails possessing more than one axoneme. Both the lumen of most seminiferous tubules and the lumina of the ductus epididymidis and the ductus deferens contain relatively few spermatozoa. We suggest that the phenotypic males inherited the

  8. Expression pattern of pluripotent markers in different embryonic developmental stages of buffalo (Bubalus bubalis) embryos and putative embryonic stem cells generated by parthenogenetic activation.

    Science.gov (United States)

    Singh, Karn P; Kaushik, Ramakant; Garg, Veena; Sharma, Ruchi; George, Aman; Singh, Manoj K; Manik, Radhey S; Palta, Prabhat; Singla, Suresh K; Chauhan, Manmohan S

    2012-12-01

    In this study, we describe the production of buffalo parthenogenetic blastocysts and subsequent isolation of parthenogenetic embryonic stem cell (PGESC)-like cells. PGESC colonies exhibited dome-shaped morphology and were clearly distinguishable from the feeder layer cells. Different stages of development of parthenogenetic embryos and derived embryonic stem cell (ESC)-like cells expressed key ESC-specific markers, including OCT-4, NANOG, SOX-2, FOXD3, REX-1, STAT-3, TELOMERASE, NUCLEOSTEMIN, and cMYC. Immunofluorescence-based studies revealed that the PGESCs were positive for surface-based pluripotent markers, viz., SSEA-3, SSEA-4, TRA 1-80, TRA 1-60, CD-9, and CD-90 and exhibited high alkaline phosphatase (ALP) activity. PGEC cell-like cells formed embryoid body (EB)-like structures in hanging drop cultures and when cultured for extended period of time spontaneously differentiated into derivatives of three embryonic germ layers as confirmed by RT-PCR for ectodermal (CYTOKERATIN8, NF-68), mesodermal (MSX1, BMP-4, ASA), and endodermal markers (AFP, HNF-4, GATA-4). Differentiation of PGESCs toward the neuronal lineage was successfully directed by supplementation of serum-containing media with retinoic acid. Our results indicate that the isolated ESC-like cells from parthenogenetic blastocyst hold properties of ESCs and express markers of pluripotency. The pluripotency markers were also expressed by early cleavage-stage of buffalo embryos.

  9. SEM study of diversity in the cyst surface topography of nine parthenogenetic Artemia (Crustacea: Anostraca) populations from China.

    Science.gov (United States)

    Asem, Alireza; Sun, Shi-Chun

    2014-12-01

    The cysts of nine Chinese populations of parthenogenetic Artemia were studied by scanning electron microscope. In the 270 cysts examined, 15 different morphological patterns were recognized with most of them not recorded in previous studies and the "tubercled shell surface" being the most common pattern. Results also displayed high intrapopulation variability, with the maximum of 11 patterns (in 30 cysts) recorded from the Barkol population. No positive correlation between the diversity of cyst shell patterns and ploidy compositions was found. Principal components analysis suggests higher similarity among coastal populations than among inland populations, which may be attributed to the identity of physicochemical conditions among coastal salterns and dissimilarity among inland saline lakes. © 2014 Wiley Periodicals, Inc.

  10. Effect of ambient light exposure of media and embryos on development and quality of porcine parthenogenetically activated embryos

    DEFF Research Database (Denmark)

    Li, Rong; Liu, Ying; Callesen, Henrik

    2015-01-01

    Light exposure is a common stress factor during in vitro handling of oocytes and embryos that originates from both microscope and ambient light. In the current study, the effect of two types of ambient light (daylight and laboratory light) on porcine parthenogenetically activated (PA) embryos...... was tested in two experiments: (1) ambient light on medium subsequently used for embryo in vitro development; and (2) ambient light exposure on activated oocytes before in vitro development. The results from Experiment 1 showed that exposure of culture medium to both types of ambient light decreased...... the percentage of blastocysts that showed good morphology, only after 24 h exposure. The results from Experiment 2 revealed a reduction in both blastocyst formation and quality when activated oocytes were exposed to both types of ambient light. This effect was seen after only 1 h exposure and increased with time...

  11. DNA methylation in porcine preimplantation embryos developed in vivo and produced by in vitro fertilization, parthenogenetic activation and somatic cell nuclear transfer

    DEFF Research Database (Denmark)

    Deshmukh, Rahul Shahaji; Østrup, Olga; Østrup, Esben

    2011-01-01

    DNA demethylation and remethylation are crucial for reprogramming of the differentiated parental/somatic genome in the recipient ooplasm upon somatic cell nuclear transfer. Here, we analyzed the DNA methylation dynamics during porcine preimplantation development. Porcine in vivo developed (IV......), in vitro fertilized (IVF), somatic cell nuclear transfer (SCNT) and parthenogenetically activated (PA) embryos were evaluated for DNA methylation quantification at different developmental stages. Fertilized (IV and IVF) one-cell stages lacked a substantial active demethylation of the paternal genome...

  12. DNA methylation in porcine preimplantation embryos developed in-vivo or produced by in-vitro fertilization, parthenogenetic activation and somatic cell nuclear transfer

    DEFF Research Database (Denmark)

    Deshmukh, Rahul Shahaji; Østrup, Olga; Østrup, Esben

    2011-01-01

    DNA demethylation and remethylation are crucial for reprogramming of the differentiated parental/somatic genome in the recipient ooplasm upon somatic cell nuclear transfer. Here, we analyzed the DNA methylation dynamics during porcine preimplantation development. Porcine in vivo developed (IV......), in vitro fertilized (IVF), somatic cell nuclear transfer (SCNT) and parthenogenetically activated (PA) embryos were evaluated for DNA methylation quantification at different developmental stages. Fertilized (IV and IVF) one-cell stages lacked a substantial active demethylation of the paternal genome...

  13. Equivalency of Buffalo (Bubalus Bubalis) Embryonic Stem Cells Derived From Fertilized, Parthenogenetic, and Hand-Made Cloned Embryos

    Science.gov (United States)

    Muzaffar, Musharifa; Selokar, Naresh L.; Singh, Karn P.; Zandi, Mohammad; Singh, Manoj K.; Shah, Riaz A.; Chauhan, Manmohan S.; Singla, Suresh K.; Palta, Prabhat

    2012-01-01

    Abstract This study was aimed at establishing buffalo embryonic stem cells (ESCs) from in vitro fertilized (IVF), parthenogenetic, and hand-made cloned (HMC) embryos and to check their equivalency in terms of stem cell marker expression, longevity, proliferation, and differentiation pattern. ESCs derived from all three sources were found by immunofluorescence to express the pluripotency markers SSEA-4, TRA-1-60, TRA-1-81, OCT4, and SOX2 and were able to form embryoid bodies containing cells expressing genes specific to endoderm (AFP, HNF4, and GATA4), mesoderm (MSX1, BMP4, and ASA), and ectoderm (cytokeratin 8 and NF68). Reverse transcriptase PCR (RT-PCR) showed cells from all sources to be positive for pluripotency markers OCT4, SOX2, NANOG, STAT3, REX1, FOXD3, NUCLEOSTEMIN, and TELOMERASE. Pluripotency markers OCT4, SOX2, NANOG, and c-MYC were also analyzed by real-time PCR. No significant differences were observed among ESCs from all three sources for all these genes except NANOG, whose expression was higher (pcells (1.603±0.315 and 1±0, respectively). Pluripotent, stable buffalo ESC lines derived from IVF, parthenogenesis, and HMC embryos may be genetically manipulated to provide a powerful tool for studies involving embryonic development, genomic imprinting, gene targeting, cloning, chimera formation, and transgenic animal production. PMID:22582863

  14. Investigating the genetic and epigenetic basis of big biological questions with the parthenogenetic marbled crayfish: A review and perspectives.

    Science.gov (United States)

    Vogt, Gunter

    2018-03-01

    In the last 15 years, considerable attempts have been undertaken to develop the obligately parthenogenetic marbled crayfish Procambarus virginalis as a new model in biology. Its main advantage is the production of large numbers of offspring that are genetically identical to the mother, making this crustacean particularly suitable for research in epigenetics. Now, a draft genome, transcriptome and genome-wide methylome are available opening new windows for research. In this article, I summarize the biological advantages and genomic and epigenetic features of marbled crayfish and, based on first promising data, discuss what this new model could contribute to answering of ''big'' biological questions. Genome mining is expected to reveal new insights into the genetic specificities of decapod crustaceans, the genetic basis of arthropod reproduction, moulting and immunity, and more general topics such as the genetic underpinning of adaptation to fresh water, omnivory, biomineralization, sexual system change, behavioural variation, clonal genome evolution, and resistance to cancer. Epigenetic investigations with the marbled crayfish can help clarifying the role of epigenetic mechanisms in gene regulation, tissue specification, adult stem cell regulation, cell ageing, organ regeneration and disease susceptibility. Marbled crayfish is further suitable to elucidate the relationship between genetic and epigenetic variation, the transgenerational inheritance of epigenetic signatures and the contribution of epigenetic phenotype variation to the establishment of social hierarchies, environmental adaptation and speciation. These issues can be tackled by experiments with highly standardized laboratory lineages, comparison of differently adapted wild populations and the generation of genetically and epigenetically edited strains.

  15. Effect of ambient light exposure of media and embryos on development and quality of porcine parthenogenetically activated embryos.

    Science.gov (United States)

    Li, Rong; Liu, Ying; Pedersen, Hanne Skovsgaard; Callesen, Henrik

    2015-06-01

    Light exposure is a common stress factor during in vitro handling of oocytes and embryos that originates from both microscope and ambient light. In the current study, the effect of two types of ambient light (daylight and laboratory light) on porcine parthenogenetically activated (PA) embryos was tested in two experiments: (1) ambient light on medium subsequently used for embryo in vitro development; and (2) ambient light exposure on activated oocytes before in vitro development. The results from Experiment 1 showed that exposure of culture medium to both types of ambient light decreased the percentage of blastocysts that showed good morphology, only after 24 h exposure. The results from Experiment 2 revealed a reduction in both blastocyst formation and quality when activated oocytes were exposed to both types of ambient light. This effect was seen after only 1 h exposure and increased with time. In conclusion, exposure to ambient light can be harmful to embryo development, both when medium is exposed for a long period of time and, to a greater extent, when the embryo itself is exposed for >1 h. In practice, it is therefore recommended to protect both culture medium and porcine embryos against ambient light during in vitro handling in the laboratory.

  16. Helminths infecting the parthenogenetic whiptail lizard Cnemidophorus nativo in a restinga habitat of Bahia State, Brazil.

    Science.gov (United States)

    Menezes, V A; Vrcibradic, D; Vicente, J J; Dutra, G F; Rocha, C F D

    2004-12-01

    A sample of 101 specimens of the unisexual whiptail lizard Cnemidophorus nativo (Squamata; Teiidae) from a coastal site in Bahia State, Brazil were examined for the presence of endoparasites. Of these, 35 (34.7%) harboured helminths. Six helminth species were recovered from C. nativo, including five nematodes (Physaloptera retusa, Physalopteroides venancioi, Subulura lacertilia, Skrjabinelazia intermedia and Parapharyngodon sp., and one cestode (Oochoristica ameivae), all representing new host records. Most lizards were infected by a single species of helminth and none by more than three. Infection rates were neither significantly influenced by host body size nor by environmental factors. The results are compared with data from studies on other whiptail species in both South and North America.

  17. Parthenogenetic embryonic stem cells with H19 siRNA-mediated knockdown as a potential resource for cell therapy.

    Science.gov (United States)

    Kwak, Minhye; Hong, Su; Yu, Seong-Lan; Sim, Bo-Woong; Seo, Jeong-Sun; Kang, Jaeku

    2012-02-01

    Embryonic stem (ES) cells are used in cell therapy and tissue engineering due to their ability to produce different cells types. However, studies of ES cells that are derived from fertilized embryos have raised concerns about the limitations imposed by ethical and political considerations. Therefore, many studies of stem cells use the stem cells that are derived from unfertilized oocytes and adult tissue. Although parthenogenetic embryonic stem (ESP) cells also avoid ethical and political dilemmas and can be used in cell-based therapy, the ESP cells exhibit growth retardation problems. Therefore, to investigate the potential for muscle growth from genetically modified ESP cells, we established four ES cell types, including normal embryonic stem (ESN) cells, ESP cells, ESP cells that overexpress the insulin-like growth factor 2 (Igf2) gene (ESI) and ESP cells with down-regulated H19 gene expression (ESH). Using these cells, we examined the expression profiles of genes that were related to imprinting and muscle using microarrays. The gene expression patterns of ESI and ESH cells were similar and were more closely related to the ESN pattern than that of the ESP cells. Differentiated ESH cells exhibited increased expression of bone morphologic protein 4 (BMP4), which is a mesoderm marker, compared with the differentiated ESI cells. We showed that Igf2 expression was induced by H19 silencing in the ESP cells via hypermethylation of the H19 imprinting control region 1 (ICR1). Moreover, the proportion of ESH-derived chimera was slightly higher than those produced from the ESP cells. In addition, we detected increased cell proliferation in the MEF cells following H19 knock-down. These results indicate that the ESH cells may be a source of cell-based therapy for conditions such as muscular atrophy.

  18. Involvement of Mos-MEK-MAPK pathway in cytostatic factor (CSF) arrest in eggs of the parthenogenetic insect, Athalia rosae.

    Science.gov (United States)

    Yamamoto, Daisuke S; Tachibana, Kazunori; Sumitani, Megumi; Lee, Jae Min; Hatakeyama, Masatsugu

    2008-01-01

    Extensive survey of meiotic metaphase II arrest during oocyte maturation in vertebrates revealed that the mitogen-activated protein kinase (MAPK) pathway regulated by the c-mos proto-oncogene product, Mos, has an essential role in cytostatic activity, termed cytostatic factor (CSF). In contrast, little is known in invertebrates in which meiotic arrest occurs in most cases at metaphase I (MI arrest). A parthenogenetic insect, the sawfly Athalia rosae, in which artificial egg activation is practicable, has advantages to investigate the mechanisms of MI arrest. Both the MAPK/extracellular signal-regulated protein kinase kinase (MEK) and MAPK were phosphorylated and maintained active in MI-arrested sawfly eggs, whereas they were dephosphorylated soon after egg activation. Treatment of MI-arrested eggs with U0126, an inhibitor of MEK, resulted in dephosphorylation of MAPK and MI arrest was resumed. The sawfly c-mos gene orthologue encoding a serine/threonine kinase was cloned and analyzed. It was expressed in nurse cells in the ovaries. To examine CSF activity of the sawfly Mos, synthesized glutathione S-transferase (GST)-fusion sawfly Mos protein was injected into MI-resumed eggs in which MEK and MAPK were dephosphorylated. Both MEK and MAPK were phosphorylated again upon injection. In these GST-fusion sawfly Mos-injected eggs subsequent mitotic (syncytial) divisions were blocked and embryonic development was ceased. These results demonstrated that the MEK-MAPK pathway was involved in maintaining CSF arrest in sawfly eggs and Mos functioned as its upstream regulatory molecule.

  19. Preclinical study of mouse pluripotent parthenogenetic embryonic stem cell derivatives for the construction of tissue-engineered skin equivalent.

    Science.gov (United States)

    Rao, Yang; Cui, Jihong; Yin, Lu; Liu, Wei; Liu, Wenguang; Sun, Mei; Yan, Xingrong; Wang, Ling; Chen, Fulin

    2016-10-22

    Embryonic stem cell (ESC) derivatives hold great promise for the construction of tissue-engineered skin equivalents (TESE). However, harvesting of ESCs destroys viable embryos and may lead to political and ethical concerns over their application. In the current study, we directed mouse parthenogenetic embryonic stem cells (pESCs) to differentiate into fibroblasts, constructed TESE, and evaluated its function in vivo. The stemness marker expression and the pluripotent differentiation ability of pESCs were tested. After embryoid body (EB) formation and adherence culture, mesenchymal stem cells (MSCs) were enriched and directed to differentiate into fibroblastic lineage. Characteristics of derived fibroblasts were assessed by quantitative real-time PCR and ELISA. Functional ability of the constructed TESE was tested by a mouse skin defects repair model. Mouse pESCs expressed stemness marker and could form teratoma containing three germ layers. MSCs could be enriched from outgrowths of EBs and directed to differentiate into fibroblastic lineage. These cells express a high level of growth factors including FGF, EGF, VEGF, TGF, PDGF, and IGF1, similar to those of ESC-derived fibroblasts and mouse fibroblasts. Seeded into collagen gels, the fibroblasts derived from pESCs could form TESE. Mouse skin defects could be successfully repaired 15 days after transplantation of TESE constructed by fibroblasts derived from pESCs. pESCs could be induced to differentiate into fibroblastic lineage, which could be applied to the construction of TESE and skin defect repair. Particularly, pESC derivatives avoid the limitations of political and ethical concerns, and provide a promising source for regenerative medicine.

  20. Analysis of expressed sequence tags of the cyclically parthenogenetic rotifer Brachionus plicatilis.

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    Koushirou Suga

    Full Text Available BACKGROUND: Rotifers are among the most common non-arthropod animals and are the most experimentally tractable members of the basal assemblage of metazoan phyla known as Gnathifera. The monogonont rotifer Brachionus plicatilis is a developing model system for ecotoxicology, aquatic ecology, cryptic speciation, and the evolution of sex, and is an important food source for finfish aquaculture. However, basic knowledge of the genome and transcriptome of any rotifer species has been lacking. METHODOLOGY/PRINCIPAL FINDINGS: We generated and partially sequenced a cDNA library from B. plicatilis and constructed a database of over 2300 expressed sequence tags corresponding to more than 450 transcripts. About 20% of the transcripts had no significant similarity to database sequences by BLAST; most of these contained open reading frames of significant length but few had recognized Pfam motifs. Sixteen transcripts accounted for 25% of the ESTs; four of these had no significant similarity to BLAST or Pfam databases. Putative up- and downstream untranslated regions are relatively short and AT rich. In contrast to bdelloid rotifers, there was no evidence of a conserved trans-spliced leader sequence among the transcripts and most genes were single-copy. CONCLUSIONS/SIGNIFICANCE: Despite the small size of this EST project it revealed several important features of the rotifer transcriptome and of individual monogonont genes. Because there is little genomic data for Gnathifera, the transcripts we found with no known function may represent genes that are species-, class-, phylum- or even superphylum-specific; the fact that some are among the most highly expressed indicates their importance. The absence of trans-spliced leader exons in this monogonont species contrasts with their abundance in bdelloid rotifers and indicates that the presence of this phenomenon can vary at the subphylum level. Our EST database provides a relatively large quantity of transcript

  1. Analysis of expressed sequence tags of the cyclically parthenogenetic rotifer Brachionus plicatilis.

    Science.gov (United States)

    Suga, Koushirou; Welch, David Mark; Tanaka, Yukari; Sakakura, Yoshitaka; Hagiwara, Atsushi

    2007-08-01

    Rotifers are among the most common non-arthropod animals and are the most experimentally tractable members of the basal assemblage of metazoan phyla known as Gnathifera. The monogonont rotifer Brachionus plicatilis is a developing model system for ecotoxicology, aquatic ecology, cryptic speciation, and the evolution of sex, and is an important food source for finfish aquaculture. However, basic knowledge of the genome and transcriptome of any rotifer species has been lacking. We generated and partially sequenced a cDNA library from B. plicatilis and constructed a database of over 2300 expressed sequence tags corresponding to more than 450 transcripts. About 20% of the transcripts had no significant similarity to database sequences by BLAST; most of these contained open reading frames of significant length but few had recognized Pfam motifs. Sixteen transcripts accounted for 25% of the ESTs; four of these had no significant similarity to BLAST or Pfam databases. Putative up- and downstream untranslated regions are relatively short and AT rich. In contrast to bdelloid rotifers, there was no evidence of a conserved trans-spliced leader sequence among the transcripts and most genes were single-copy. Despite the small size of this EST project it revealed several important features of the rotifer transcriptome and of individual monogonont genes. Because there is little genomic data for Gnathifera, the transcripts we found with no known function may represent genes that are species-, class-, phylum- or even superphylum-specific; the fact that some are among the most highly expressed indicates their importance. The absence of trans-spliced leader exons in this monogonont species contrasts with their abundance in bdelloid rotifers and indicates that the presence of this phenomenon can vary at the subphylum level. Our EST database provides a relatively large quantity of transcript-level data for B. plicatilis, and more generally of rotifers and other gnathiferan phyla, and

  2. Brine shrimp bioassay: importance of correct taxonomic identification of Artemia (Anostraca) species.

    Science.gov (United States)

    Ruebhart, David R; Cock, Ian E; Shaw, Glen R

    2008-08-01

    Despite the common use of the brine shrimp bioassay in toxicology, there is confusion in the literature regarding citation of the correct taxonomic identity of the Artemia species used. The genus Artemia, once thought to be represented by a single species Artemia salina, is now known to be composed of several bisexual species as well as parthenogenetic populations. Artemia franciscana is the best studied of the Artemia species and is considered to represent the vast majority of studies in which Artemia is used as an experimental test organism. We found that in studies referring to the use of A. salina, the zoogeography of the cyst harvest site indicated that the species used was actually A. franciscana. Those performing bioassays with Artemia need to exercise diligence in assigning correct species identification, as the identity of the test organism is an important parameter in assuring the validity of the results of the assay.

  3. Species differences in the regulation of tyrosine hydroxylase in Cnemidophorus whiptail lizards.

    Science.gov (United States)

    Woolley, Sarah C; Crews, David

    2004-09-05

    Evolution of behavioral phenotype involves changes in the underlying neural substrates. Cnemidophorus whiptail lizards enable the study of behavioral and neural evolution because ancestral species involved in producing unisexual, hybrid species still exist. Catecholaminergic systems modulate the expression of social behaviors in a number of vertebrates, including whiptails, and therefore we investigated how changes in catecholamine production correlated with evolutionary changes in behavioral phenotype by measuring the size and number of catecholamine producing (tyrosine hydroxylase-immunoreactive, or TH-ir) cells across the reproductive cycle in females from two related whiptail species. Cnemidophorusuniparens is a triploid, parthenogenetic species that arose from hybridization events involving the diploid, sexual species C. inornatus. Prior to ovulation, females from both species display femalelike receptive behaviors. However, after ovulation, only parthenogenetic individuals display malelike mounting behavior. In all nuclei measured, we found larger TH-ir cells in the parthenogen, a difference consistent with species differences in ploidy. In contrast, species differences in the number of TH-ir cells were nucleus specific. In the preoptic area and anterior hypothalamus, parthenogens had fewer TH-ir cells than females of the sexual species. Reproductive state only affected TH-ir cell number in the substantia nigra pars compacta (SNpc), and C. uniparens individuals had more TH-ir cells after ovulation than when previtellogenic. Thus, species differences over the reproductive cycle in the SNpc are correlated with species differences in behavior, and it appears that the process of speciation may have produced a novel neural and behavioral phenotype in the parthenogen.

  4. Female parthenogenetic apomixis and androsporogenetic parthenogenesis in embryonal cells of Araucaria angustifolia: interpolation of progenesis and asexual heterospory in an artificial sporangium.

    Science.gov (United States)

    Durzan, Don J

    2012-09-01

    Cell fate, development timing and occurrence of reproductive versus apomictic development in gymnosperms are shown to be influenced by culture conditions in vitro. In this study, female parthenogenetic apomixis (fPA), androsporogenetic parthenogenesis (mAP) and progenesis were demonstrated using embryonal initials of Araucaria angustifolia in scaled-up cell suspensions passing through a single-cell bottleneck in darkness and in an artificial sporangium (AS). Expression was based on defined nutrition, hormones and feedforward-adaptive feedback process controls at 23-25 °C and in darkness. In fPA, the nucleus of an embryonal initial undergoes endomitosis and amitosis, forming a diploid egg-equivalent and an apoptotic ventral canal nucleus in a transdifferentiated archegonial tube. Discharge of egg-equivalent cells as parthenospores and their dispersal into the aqueous culture medium were followed by free-nuclear conifer-type proembryogenesis. This replaced the plesiomorphic and central features of proembryogenesis in Araucariaceae. Protoplasmic fusions of embryonal initials were used to reconstruct heterokaryotic expressions of fPA in multiwell plates. In mAP, restitutional meiosis (automixis) was responsible for androsporogenesis and the discharge of monads, dyads, tetrads and polyads. In a display of progenesis, reproductive development was brought to an earlier ontogenetic stage and expressed by embryonal initials. Colchicine increased polyploidy, but androspore formation became aberrant and fragmented. Aberrant automixis led to the formation of chromosomal bouquets, which contributed to genomic silencing in embryonal initials, cytomixis and the formation of pycnotic micronucleated cells. Dispersal of female and male parthenospores displayed heteromorphic asexual heterospory in an aqueous environment.

  5. Sex-biased dispersal creates spatial genetic structure in a parthenogenetic ant with a dependent-lineage reproductive system.

    Science.gov (United States)

    Kuhn, A; Bauman, D; Darras, H; Aron, S

    2017-10-01

    Reproduction and dispersal are key aspects of species life history that influence spatial genetic structure in populations. Several ant species in the genus Cataglyphis have evolved a unique breeding system in which new reproductives (that is, queens and males) are produced asexually by parthenogenesis; in contrast, non-reproductives (that is, workers) are produced via sexual reproduction by mates from distinct genetic lineages. We investigated how these two coexisting reproductive methods affect population-level spatial genetic structure using the ant Cataglyphis mauritanica as a model. We obtained genotypes for queens and their male mates from 338 colonies, and we found that the two lineages present in the study population occurred with equal frequency. Furthermore, analysis of spatial genetic structure revealed strong sex-biased dispersal. Because queens were produced by parthenogenesis and because they dispersed over short distances, there was an extreme level of spatial structuring: a mosaic of patches composed of clonal queens was formed. Males, on the other hand, dispersed over several hundred metres and, thus, across patches, ensuring successful interlineage mating.

  6. Sex steroid hormones during the ovarian cycle of an all-female, parthenogenetic lizard and their correlation with pseudosexual behavior.

    Science.gov (United States)

    Moore, M C; Whittier, J M; Crews, D

    1985-11-01

    Cnemidophorus uniparens is a unisexual lizard that reproduces by parthenogenesis. Individuals of this species display male-like and female-like copulatory behaviors during different phases of the ovarian cycle suggesting that these pseudocopulatory behaviors are hormonally activated. To learn more about both the endocrinology of parthenogenesis and the possible hormonal activation of male-like copulatory behavior in female individuals, we (1) characterized changes in plasma levels of the sex steroid hormones progesterone, 5 alpha-dihydrotestosterone, testosterone, and 17 beta-estradiol during the ovarian cycle in both free-living and captive individuals, and (2) measured sex steroid hormones in plasma collected from captive individuals immediately after they expressed male-like or female-like copulatory behavior. In general, the pattern of secretion of ovarian hormones in C. uniparens appears to be similar to that of other oviparous vertebrates with similar reproductive cycles. Estradiol is elevated only during the preovulatory phase, whereas progesterone increases slightly during vitellogenesis and then increases dramatically following ovulation. Circulating levels of androgen are very low and are generally below the sensitivity of our radioimmunoassay at all stages of the ovarian cycle. The hormonal correlates of female-like copulatory behavior suggest that, as in other vertebrates, female receptivity is activated by a synergism of estradiol and progesterone. There is no evidence that the hormonal cycle has been altered to produce elevated levels of androgens during the phase of the cycle when male-like behavior is expressed. Rather it seems more likely that the central nervous system has evolved a novel response to a typical pattern of ovarian steroid hormone secretion. At present, the best hormonal correlate of male-like behavior is that changes in plasma levels of progesterone closely parallel changes in probability of expressing male-like behavior.

  7. Goat oocyte quality and competence to undergo IVM and embryo development after parthenogenetic activation from goats fed with different levels of cashew nut bran as source of dietary lipids.

    Science.gov (United States)

    Fernandes, C C L; Feltrin, C; Martins, L T; Gaudêncio Neto, S; Aguiar, L H; Silva, A M; Oliveira, C H A; Silva, L M; Silva, C M G; Bertolini, M; Rondina, D

    2014-07-15

    Lipid-rich and energy-dense diets can have significant effects on the reproductive physiology, including the ovarian function and fertility. The aim of this study was to assess the effect of cashew nut bran supplementation as a lipid source on follicle development, plasma and intrafollicular concentrations of cholesterol, and developmental competence of in vitro-matured goat oocytes. The inclusion of cashew nut bran as 24% of the goats' diet for 28 days increased the percentage and number of degenerated oocytes compared with the control (P diet. In conclusion, the inclusion of cashew nut bran as 24% of the diet of adult goats for 28 days changed plasma cholesterol levels and reduced the proportion of viable immature oocytes; however, the 12% and 24% diet supplementations with cashew nut bran did not interfere with competence of resulting viable oocytes to reach the metaphase II stage after IVM, and to develop after parthenogenetic activation. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Aquatic pollution may favor the success of the invasive species A. franciscana

    International Nuclear Information System (INIS)

    Varó, I.; Redón, S.; Garcia-Roger, E.M.; Amat, F.; Guinot, D.; Serrano, R.; Navarro, J.C.

    2015-01-01

    Highlights: • Artemia species display an elevated tolerance to high ranges of chlorpyrifos. • A. franciscana survived better and its fecundity was less affected by chlorpyrifos. • The higher fecundity of A. franciscana is a selective advantage in colonization processes. • Higher survival and biological fitness in A. franciscana indicate out-competitive advantages. - Abstract: The genus Artemia consists of several bisexual and parthenogenetic sibling species. One of them, A. franciscana, originally restricted to the New World, becomes invasive when introduced into ecosystems out of its natural range of distribution. Invasiveness is anthropically favored by the use of cryptobiotic eggs in the aquaculture and pet trade. The mechanisms of out-competition of the autochthonous Artemia by the invader are still poorly understood. Ecological fitness may play a pivotal role, but other underlying biotic and abiotic factors may contribute. Since the presence of toxicants in hypersaline aquatic ecosystems has been documented, our aim here is to study the potential role of an organophosphate pesticide, chlorpyrifos, in a congeneric mechanism of competition between the bisexual A. franciscana (AF), and one of the Old World parthenogenetic siblings, A. parthenogenetica (PD). For this purpose we carried out life table experiments with both species, under different concentrations of the toxicant (0.1, 1 and 5 μg/l), and analyzed the cholinesterase inhibition at different developmental stages. The results evidence that both, AF and PD, showed an elevated tolerance to high ranges of chlorpyrifos, but AF survived better and its fecundity was less affected by the exposure to the pesticide than that of PD. The higher fecundity of AF is a selective advantage in colonization processes leading to its establishment as NIS. Besides, under the potential selective pressure of abiotic factors, such as the presence of toxicants, its higher resistance in terms of survival and biological

  9. Aquatic pollution may favor the success of the invasive species A. franciscana

    Energy Technology Data Exchange (ETDEWEB)

    Varó, I., E-mail: inma@iats.csic.es [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain); Redón, S. [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain); Garcia-Roger, E.M. [Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Burjassot (Spain); Amat, F.; Guinot, D. [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain); Serrano, R. [Research Institute for Pesticides and Water (IUPA), Avda. Sos Baynat, s/n. University Jaume I, Castellón 12071 (Spain); Navarro, J.C. [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain)

    2015-04-15

    Highlights: • Artemia species display an elevated tolerance to high ranges of chlorpyrifos. • A. franciscana survived better and its fecundity was less affected by chlorpyrifos. • The higher fecundity of A. franciscana is a selective advantage in colonization processes. • Higher survival and biological fitness in A. franciscana indicate out-competitive advantages. - Abstract: The genus Artemia consists of several bisexual and parthenogenetic sibling species. One of them, A. franciscana, originally restricted to the New World, becomes invasive when introduced into ecosystems out of its natural range of distribution. Invasiveness is anthropically favored by the use of cryptobiotic eggs in the aquaculture and pet trade. The mechanisms of out-competition of the autochthonous Artemia by the invader are still poorly understood. Ecological fitness may play a pivotal role, but other underlying biotic and abiotic factors may contribute. Since the presence of toxicants in hypersaline aquatic ecosystems has been documented, our aim here is to study the potential role of an organophosphate pesticide, chlorpyrifos, in a congeneric mechanism of competition between the bisexual A. franciscana (AF), and one of the Old World parthenogenetic siblings, A. parthenogenetica (PD). For this purpose we carried out life table experiments with both species, under different concentrations of the toxicant (0.1, 1 and 5 μg/l), and analyzed the cholinesterase inhibition at different developmental stages. The results evidence that both, AF and PD, showed an elevated tolerance to high ranges of chlorpyrifos, but AF survived better and its fecundity was less affected by the exposure to the pesticide than that of PD. The higher fecundity of AF is a selective advantage in colonization processes leading to its establishment as NIS. Besides, under the potential selective pressure of abiotic factors, such as the presence of toxicants, its higher resistance in terms of survival and biological

  10. Clutch size in populations and species of cnemidophorines (Squamata: Teiidae on the eastern coast of Brazil

    Directory of Open Access Journals (Sweden)

    VANDERLAINE A. MENEZES

    2014-06-01

    Full Text Available We analyzed some reproductive aspects of 16 coastal populations, belonging to five lizard species (A. ocellifera, A. abaetensis, A. nativo, A. littoralis and C. lacertoides from different restinga habitats along the eastern coast of Brazil. This study aimed to evaluate to what extent the reproductive aspects vary geographically and among species. For each female, we recorded the number of vitellogenic follicles, size and color of the largest follicle, presence and size of corpora lutea, and number and size of oviductal eggs. Clutch size of almost all coastal populations/species of Ameivula had little variation and most clutches were composed of two eggs. There was a significant relationship between female size and the mean clutch size when females from different species were pooled. Mean egg volume, among species, varied from 420 to 655 mm3. Relative clutch mass varied from 0.129 to 0.159 and did not differ significantly among species. We concluded that the five coastal species studied (four bisexuals and one parthenogenetic had similar reproductive characteristics. Most of them presented multiple clutches, low clutch size and low relative clutch mass, similar to other species in the genus and to unisexual and bisexual species of the Teiidae family.

  11. Morphology of the European species of the aphid genus Eulachnus (Hemiptera: Aphididae: Lachninae) - A SEM comparative and integrative study.

    Science.gov (United States)

    Kanturski, Mariusz; Karcz, Jagna; Wieczorek, Karina

    2015-09-01

    Scanning electron microscopy (SEM) methods were used for the first time to elucidate the external morphology of the European species of the genus Eulachnus (Hemiptera: Aphididae: Lachninae), a representative genus of the conifer-feeding aphids tribe Eulachnini. We examined and compared the external morphology of apterous and alate viviparous females from the parthenogenetic generation as well as oviparous females and alate males belonging to the sexual generation. FE-SEM images based on HMDS and cryo-SEM preparation techniques revealed better image quality than the CPD technique in regard to surface tension and morphological signs of cell deteriorations (i.e., existence of depressions, drying artifacts and membrane blebs). Three morphologically different species groups "agilis", "brevipilosus" and "cembrae" were proposed due to the differences in head, antennae, legs and dorsal chaetotaxy as well as dorsal sclerotization. The most characteristic features and differences of representatives of these groups are presented and discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Endangered Species

    Science.gov (United States)

    EPA's Endangered Species Protection Program helps promote recovery of listed species. The ESPP determines if pesticide use in a geographic area may affect any listed species. Find needed limits on pesticide use in Endangered Species Protection Bulletins.

  13. Molecular evolution in Panagrolaimus nematodes: origins of parthenogenesis, hermaphroditism and the Antarctic species P. davidi

    Directory of Open Access Journals (Sweden)

    LaMunyon Craig W

    2009-01-01

    Full Text Available Abstract Background As exemplified by the famously successful model organism Caenorhabditis elegans, nematodes offer outstanding animal systems for investigating diverse biological phenomena due to their small genome sizes, short generation times and ease of laboratory maintenance. Nematodes in the genus Panagrolaimus have served in comparative development and anhydrobiosis studies, and the Antarctic species P. davidi offers a powerful paradigm for understanding the biological mechanisms of extreme cold tolerance. Panagrolaimus nematodes are also unique in that examples of gonochoristic, hermaphroditic and parthenogenetic reproductive modes have been reported for members of this genus. The evolutionary origins of these varying reproductive modes and the Antarctic species P. davidi, however, remain enigmatic. Results We collected nuclear ribosomal RNA gene and mitochondrial protein-coding gene sequences from diverse Panagrolaimus species and strains, including newly discovered isolates from Oregon, to investigate phylogenetic relationships in this nematode genus. Nuclear phylogenies showed that the species and strains historically identified as members of Panagrolaimus constitute a paraphyletic group, suggesting that taxonomic revision is required for Panagrolaimus and related nematode lineages. Strain-specific reproductive modes were mapped onto the molecular phylogeny to show a single origin of parthenogenesis from a presumably gonochoristic ancestor. The hermaphroditic strains were all placed outside a major monophyletic clade that contained the majority of other Panagrolaimus nematodes. Phylogenetic analyses of mitochondrial sequences showed that substantial molecular and geographic diversity exists within the clade of parthenogenetic strains. The Antarctic species P. davidi was found to be very closely related to two Panagrolaimus strains from southern California. Phylogenetic and molecular clock analyses suggested that P. davidi and the

  14. A review of the ever increasing threat to European crayfish from non-indigenous crayfish species

    Directory of Open Access Journals (Sweden)

    D.M. Holdich

    2009-01-01

    Full Text Available Non-indigenous crayfish species (NICS in Europe now outnumber indigenous crayfish species (ICS 2:1, and it has been predicted that they may dominate completely in the next few decades unless something is done to protect them. Of the ten NICS introduced at least nine have become established in areas occupied by four of the five ICS. A decline in stocks of ICS has been recorded in many countries in the face of increasing populations of NICS. Most European countries retain at least one ICS but all are under threat from habitat loss, deteriorating water quality, overfishing, climate change, and most importantly from NICS and crayfish plague. The threat to ICS is so great in some countries that “ark”sanctuary sites are being established.The three most widely-spread NICS are the North American species: Pacifastacus leniusculus, Orconectes limosus and Procambarus clarkii. These can be considered as “Old NICS”, which were introduced before 1975, compared with the “New NICS”, which were introduced after 1980, such as the North American species: Orconectes immunis, Orconectes juvenilis, Orconectes virilis, Procambarus sp. and Procambarus acutus; and the Australian species: Cherax destructor and Cherax quadricarinatus, all of which have much narrower ranges in Europe. The North American species are potentially capable of acting as vectors of crayfish plague. Outbreaks of this disease occur regularly where there are high concentrations of vectors.In addition to the NICS currently established in the wild, a further threat exists through the aquarium trade, where many American and Australian species are available via the internet and in aquarist centres. Owners of such species may discard them into the freshwater environment when they grow too big as with some Cherax spp. and Orconectes spp., or multiply too frequently as with Procambarus sp. (a parthenogenetic species. A conceptual model is presented as a possible way forward for protecting the

  15. Cost of reproduction in selected species of zooplankton (rotifers and cladocerans)

    NARCIS (Netherlands)

    Sarma, S.S.S.; Nandini, S.; Gulati, R.D.

    2002-01-01

    Reproduction is an energetically costly biological process. Among the freshwater zooplankton, rotifers and cladocerans reproduce parthenogenetically and the cost of reproduction can be estimated using the life table data from demographic studies. Reduced probability of future survival or future

  16. Differences in the reliance on cuticular hydrocarbons as sexual signaling and species discrimination cues in parasitoid wasps.

    Science.gov (United States)

    Buellesbach, Jan; Vetter, Sebastian G; Schmitt, Thomas

    2018-01-01

    Cuticular hydrocarbons (CHC) have been documented to play crucial roles as species- and sex-specific cues in the chemical communication systems of a wide variety of insects. However, whether they are sufficient by themselves as the sole cue triggering sexual behavior as well as preference of con- over heterospecific mating partners is rarely assessed. We conducted behavioral assays in three representative species of parasitoid wasps (Hymenoptera: Pteromalidae) to determine their reliance on CHC as species-specific sexual signaling cues. We found a surprising degree of either unspecific or insufficient sexual signaling when CHC are singled out as recognition cues. Most strikingly, the cosmopolitan species Nasonia vitripennis , expected to experience enhanced selection pressure to discriminate against other co-occurring parasitoids, did not discriminate against CHC of a partially sympatric species from another genus, Trichomalopsis sarcophagae . Focusing on the latter species, in turn, it became apparent that CHC are even insufficient as the sole cue triggering conspecific sexual behavior, hinting at the requirement of additional, synergistic sexual cues particularly important in this species. Finally, in the phylogenetically and chemically most divergent species Muscidifurax uniraptor, we intriguingly found both CHC-based sexual signaling as well as species discrimination behavior intact although this species is naturally parthenogenetic with sexual reproduction only occurring under laboratory conditions. Our findings implicate a discrepancy in the reliance on and specificity of CHC as sexual cues in our tested parasitioid wasps. CHC profiles were not sufficient for unambiguous discrimination and preference behavior, as demonstrated by clear cross-attraction between some of our tested wasp genera. Moreover, we could show that only in T. sarcophagae , additional behavioral cues need to be present for triggering natural mating behavior, hinting at an interesting

  17. SALMONELLA SPECIES

    African Journals Online (AJOL)

    DR. AMINU

    ... of Salmonella species serotypes in relation to age and sex among children, ..... However, most antimicrobials show sufficient selective toxicity to be of value in ... salmonellosis should be given good attention (Barrow et al., 2007). To reduce ...

  18. A new oomycete species parasitic in nematodes, Chlamydomyzium dictyuchoides sp. nov.: developmental biology and phylogenetic studies.

    Science.gov (United States)

    Beakes, Gordon W; Glockling, Sally L; James, Timothy Y

    2014-07-01

    The genus Chlamydomyzium is a little studied holocarpic oomycete parasite of nematodes of uncertain phylogenetic and taxonomic position. A new holocarpic species, Chlamydomyzium dictyuchoides, is described which has usually refractile cytoplasm and a dictyuchoid pattern of spore release. This new species infects bacteriotrophic rhabditid nematodes and was isolated from diverse geographical locations. Infection was initiated by zoospore encystment on the host surface and direct penetration of the cuticle. A sparsely branched, constricted, refractile thallus was formed which eventually occupied almost the entire host body cavity, often accompanied by complete dissolution of the host cuticle. Walled primary cysts formed throughout the thallus and each cyst released a single zoospore via an individual exit papillum, leaving a characteristic dictyuchoid wall net behind. At later stages of infection some thalli formed thick-walled stellate resting spores in uniseriate rows. Resting spore formation appeared to be parthenogenetic and was not accompanied by the formation of antheridial compartments. These spores had ooplast-like vacuoles and thick multi-layered walls, both of which suggest they were oospores. The maximum likelihood tree of sequences of the small ribosomal subunit (SSU) gene placed this new isolate in a clade before the main saprolegnialean and peronosporalean lines diverge. A second undescribed Chlamydomyzium sp., which has direct spore release forms a paraphyletic clade, close to C. dictyuchoides and Sapromyces. The fine structure of other documented Chlamydomyzium species was compared, including an undescribed (but sequenced) isolate, SL02, from Japan, Chlamydomyzium anomalum and Chlamydomyzium oviparasiticum. Chlamydomyzium as currently constituted is a paraphyletic genus that is part of a group of phylogenetically problematic early diverging clades that lie close to both the Leptomitales and Rhipidiales. Crown Copyright © 2014. Published by Elsevier

  19. Endangered Species Day | Endangered Species Coalition

    Science.gov (United States)

    Annual Top 10 Report Protecting the Endangered Species Act Wildlife Voices Stand for Wolves Endangered Campaigns Wildlife Voices Protecting the Endangered Species Act Annual Top 10 Report Endangered Species Day Stand for Wolves Vanishing BOOK: A Wild Success The Endangered Species Act at 40 Endangered Species The

  20. Morphological and biological study of Rhabdias spp. (Nematoda from african chameleons with description of a new species

    Directory of Open Access Journals (Sweden)

    Lhermitte-Vallarino N.

    2004-03-01

    Full Text Available Lung-dwelling females of Rhabdias (Rhabdiasidae, and possible migrating ceolomic young females were searched for in 46 chameleons, belonging to seven species. Rhabdias chamaeleonis, the single species identified to date in Africa, was found in Chamaeleo (Trioceros johnstoni and C. (T. hoehnelii, and redescribed ; the sizes of the buccal capsule and oesophagus were stable compared to the length of the female parasites, which varied from 6 mm to 22 mm in length. A second species, R. jarki n, sp., was identified from one C. (T. johnstoni ; it differed from R. chamaeleonis in the shape of anterior region, the longer and slender oesophagus (ratio bulb diameter-body diameter at that level about 1/5 instead of 1/2, the arrangement of the head papillae, the shape of the buccal capsule, and the anatomy of the genital apparatus : one of the ovaries (the anterior or posterior one according to the specimen had a band of small cells, among larger ovocytes of the synapsis zone, which were likely to generate the spermatozoa present in the oviducts, whereas these two elements were absent from R. chamaeleonis. The parasitic females of R. jarki thus appeared to be hermaphroditic, whereas those of R. chamaeleonis appeared to be parthenogenetic. The free living phase of these Rhabdias species was heterogonic. The infective larva of R. chamaeleonis was 360-590 µm long, unmotile and at third stage inside the maternal cuticle. The free-living male of R. jarki was described. The numerous infective larvae recovered from cultures of unidentified Rhabdias were all in maternal cuticle (one larva/female instead of two as in R. gemellipara from Calumma parsonii, from Madagascar and two kinds of larvae were identified, R. chamaeleonis and larvae 700-900 µm long provisionally identified to R. jarki. The behaviour of infective larvae and a few successful infections of insects suggest that, in the field, insect transport hosts are involved in transmission and in preventing

  1. Species concept and speciation

    Directory of Open Access Journals (Sweden)

    Amal Y. Aldhebiani

    2018-03-01

    Full Text Available Defining and recognizing a species has been a controversial issue for a long time. To determine the variation and the limitation between species, many concepts have been proposed. When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa. In this paper some of species concepts are discussed starting from the typological species concepts to the phylogenetic concept. Positive and negative aspects of these concepts are represented in addition to their application. Keywords: Species concept, Species limitation, Species, Taxonomy, Classification

  2. DNA barcodes to identify species and explore diversity in the Adelgidae (Insecta: Hemiptera: Aphidoidea)

    Science.gov (United States)

    R.G. Foottit; H.E.L. Maw; N.P. Havill; R.G. Ahern; M.E. Montgomery

    2009-01-01

    The Adelgidae are relatively small, cryptic insects, exhibiting complex life cycles with parthenogenetic reproduction. Due to these characteristics, the taxonomy of the group is problematic. Here, we test the effectiveness of the standard 658-bp barcode fragment from the 5'-end of the mitochondrial cytochrome c oxidase 1 gene (COI) in...

  3. Species accounts. Chapter 4

    Science.gov (United States)

    Margaret K. Trani; W. Mark Ford; Brian R., eds. Chapman

    2007-01-01

    Narrative accounts for each species are presented by several authors in a consistent format to convey specific information relative to that mammal. The orders are arranged phylogenetically; families and species are arranged alphabetically to facilitate finding a particular species.

  4. Alteration of sexual reproduction and genetic diversity in the kelp species Laminaria digitata at the southern limit of its range.

    Directory of Open Access Journals (Sweden)

    Luz Valeria Oppliger

    Full Text Available Adaptation to marginal habitats at species range-limits has often been associated with parthenogenetic reproduction in terrestrial animals and plants. Laboratory observations have shown that brown algae exhibit a high propensity for parthenogenesis by various mechanisms. The kelp Laminaria digitata is an important component of the ecosystem in Northern European rocky intertidal habitats. We studied four L. digitata populations for the effects of marginality on genetic diversity and sexual reproduction. Two populations were marginal: One (Locquirec, in Northern Brittany was well within the geographic range, but was genetically isolated from other populations by large stretches of sandy beaches. Another population was at the range limits of the species (Quiberon, in Southern Brittany and was exposed to much higher seasonal temperature changes. Microsatellite analyses confirmed that these populations showed decreased genetic and allelic diversity, consistent with marginality and genetic isolation. Sporophytes from both marginal populations showed greatly diminished spore-production compared to central populations, but only the southern-limit population (Quiberon showed a high propensity for producing unreduced (2N spores. Unreduced 2N spores formed phenotypically normal gametophytes with nuclear area consistent with ≥2N DNA contents, and microsatellite studies suggested these were produced at least in part by automixis. However, despite this being the dominant path of spore production in Quiberon sporophyte individuals, the genetic evidence indicated the population was maintained mostly by sexual reproduction. Thus, although spore production and development showed the expected tendency of geographical parthenogenesis in marginal populations, this appeared to be a consequence of maladaptation, rather than an adaptation to, life in a marginal habitat.

  5. Agroforestry Species Switchboard

    DEFF Research Database (Denmark)

    Kindt, R.; John, I.; Ordonez, J.

    2016-01-01

    The current version of the Agroforestry Species Switchboard documents the presence of a total of 26,135 plant species (33,813 species including synonyms) across 19 web-based databases. When available, hyperlinks to information on the selected species in particular databases are provided. In total...

  6. Endangered Species Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of the Endangered Species Act (ESA) is to protect and recover imperiled species and the ecosystems upon which they depend. The U.S. Fish and Wildlife...

  7. Endangered Species Protection Bulletins

    Science.gov (United States)

    Endangered Species Protection Bulletins set forth geographically specific pesticide use limitations for the protection of threatened and endangered (listed) species and their designated critical habitat. Find out how to get and use Bulletins.

  8. Species diversity modulates predation

    NARCIS (Netherlands)

    Kratina, P.; Vos, M.; Anholt, B.R.

    2007-01-01

    Predation occurs in a context defined by both prey and non-prey species. At present it is largely unknown how species diversity in general, and species that are not included in a predator's diet in particular, modify predator–prey interactions.Therefore we studied how both the density and diversity

  9. Dual effect of fetal bovine serum on early development depends on stage-specific reactive oxygen species demands in pigs.

    Directory of Open Access Journals (Sweden)

    Seong-Eun Mun

    Full Text Available Despite the application of numerous supplements to improve in vitro culture (IVC conditions of mammalian cells, studies regarding the effect of fetal bovine serum (FBS on mammalian early embryogenesis, particularly in relation to redox homeostasis, are lacking. Herein, we demonstrated that early development of in vitro-produced (IVP porcine embryos highly depends on the combination of FBS supplementation timing and embryonic reactive oxygen species (ROS requirements. Interestingly, FBS significantly reduced intracellular ROS levels in parthenogenetically activated (PA embryos regardless of the developmental stage. However, the beneficial effect of FBS on early embryogenesis was found only during the late phase (IVC 4-6 days treatment group. In particular, developmental competence parameters, such as blastocyst formation rate, cellular survival, total cell number and trophectoderm proportion, were markedly increased by FBS supplementation during the late IVC phase. In addition, treatment with FBS elevated antioxidant transcript levels during the late IVC phase. In contrast, supplementation with FBS during the entire period (1-6 days or during the early IVC phase (1-2 days greatly impaired the developmental parameters. Consistent with the results from PA embryos, the developmental competence of in vitro fertilization (IVF or somatic cell nuclear transfer (SCNT embryos were markedly improved by treatment with FBS during the late IVC phase. Moreover, the embryonic stage-specific effects of FBS were reversed by the addition of an oxidant and were mimicked by treatment with an antioxidant. These findings may increase our understanding of redox-dependent early embryogenesis and contribute to the large-scale production of high-quality IVP embryos.

  10. Species choice, provenance and species trials among native Brazilian species

    Energy Technology Data Exchange (ETDEWEB)

    Drumond, M A

    1982-01-01

    Six papers from the conference are presented. Drumond, M.A., Potential of species native to the semi-arid tropics, 766-781, (Refs. 18), reports on Anadenanthera macrocarpa, Mimosa species, Schinopsis brasiliensis, Spondias tuberosa, Ziziphus joazeiro, Cnidoscolus phyllacanthus, Bursera leptophleos (leptophloeos), Tabebuia impetiginosa, Astronium urundeuva, and Mimosa caesalpinia. Monteiro, R.F.R., Speltz, R.M., Gurgel, J.T. do A.; Silvicultural performance of 24 provenances of Araucaria angustifolia in Parana, 814-824, (Refs. 8). Pires, C.L. da S., Kalil Filho, A.N., Rosa, P.R.F. da, Parente, P.R., Zanatto, A.C.S.; Provenance trials of Cordia alliodora in the State of Sao Paulo, 988-995, (Refs. 9). Nogueira, J.C.B., Siqueira, A.C.M.F., Garrido, M.A.O., Gurgel Garrido, L.M. do A., Rosa, P.R.F., Moraes, J.L. de, Zandarin, M.A., Gurgel Filho, O.A., Trials of some native species in various regions of the State of Sao Paulo, 1051-1063, (Refs. 9) describes Centrolobium tomentosum, Peltophorum dubium, Tabebuia vellosoi, Cariniana legalis, and Balfourodendron riedelianum. Batista, M.P., Borges, J.F., Franco, M.A.B.; Early growth of a native species in comparison with exotics in northeastern Para, Brazil, 1105-1110, (Refs. 3). Jacaranda copaia is compared with Gmelina arborea, Pinus caribaea various hondurensis, Eucalyptus deglupta, and E. urophylla. Lima, P.C.F., Souza, S.M. de, Drumond, M.A.; Trials of native forest species at Petrolina, Pernambuco, 1139-1148, (Refs. 8), deals with Anadenanthera macrocarpa, Piptadenia obliqua, Pithecellobium foliolosum, Astronium urundeuva, Schinopsis brasiliensis, Cassia excelsa, Caesalpinia pyramidalis, Parkia platycephala, Pseudobombax simplicifolium, Tabebuia impetiginosa, Caesalpinia ferrea, and Aspidosperma pyrifolium. 18 references.

  11. Cyst quality and hatching in parthenogenetic brine shrimp, Artemia

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.; Sumitra-Vijayaraghavan; Krishnakumari, L.; Ramaiah, N.

    ) enhance the percentage of hatching of the cysts. On the basis of naupliar size, low ash content and high protein content it can be suggested that this strain is likely to be preferred by predators...

  12. Parthenogenetic stem cells for tissue-engineered heart repair

    NARCIS (Netherlands)

    Didie, Michael; Christalla, Peter; Rubart, Michael; Muppala, Vijayakumar; Doeker, Stephan; Unsoeld, Bernhard; El-Armouche, Ali; Rau, Thomas; Eschenhagen, Thomas; Schwoerer, Alexander P.; Ehmke, Heimo; Schumacher, Udo; Fuchs, Sigrid; Lange, Claudia; Becker, Alexander; Tao, Wen; Scherschel, John A.; Soonpaa, Mark H.; Yang, Tao; Lin, Qiong; Zenke, Martin; Han, Dong-Wook; Schoeler, Hans R.; Rudolph, Cornelia; Steinemann, Doris; Schlegelberger, Brigitte; Kattman, Steve; Witty, Alec; Keller, Gordon; Field, Loren J.; Zimmermann, Wolfram-Hubertus

    Uniparental parthenotes are considered an unwanted byproduct of in vitro fertilization. In utero parthenote development is severely compromised by defective organogenesis and in particular by defective cardiogenesis. Although developmentally compromised, apparently pluripotent stem cells can be

  13. Using parthenogenetic lineages to identify advantages of sex

    NARCIS (Netherlands)

    Neiman, Maurine; Schwander, Tanja

    The overwhelming predominance of sexual reproduction in nature is surprising given that sex is expected to confer profound costs in terms of production of males and the breakup of beneficial allele combinations. Recognition of these theoretical costs was the inspiration for a large body of empirical

  14. Separation of chemical species

    International Nuclear Information System (INIS)

    Rentzepis, P.M.

    1977-01-01

    Isotopic separation is accomplished by (1) a second photon irradiation step for selective ionization of a first isotopic species and (2) selective precipitation of a generally immiscible liquid from the saturating vapor phase on the ionized species. The first photon corresponds with a sharply defined spectral portion of the irradiation which exclusively excites the first species to a vibrational level. The second photon further excites this species to its ionization level. Selective precipitation is by coulombic attraction between the ionized species and the vapor. The procedure is applicable to any vapor phase ionizable material

  15. Tardigrade eggs and exuviae in Antarctic lake sediments: insights into Holocene dynamics and origins of the fauna

    Directory of Open Access Journals (Sweden)

    Sandra J. MCINNES

    2007-09-01

    Full Text Available The preservation of tardigrade eggs and exuviae in Antarctic lake sediments provided an opportunity to assess post-glacial colonisation and Holocene tardigrade dynamics on the southern continent. Tardigrade eggs were recovered from five lakes, two from the maritime Antarctic and three from continental Antarctica. Eggs were identified from the following species: Dactylobiotus cf. ambiguus, Macrobiotus furciger, Macrobiotus blocki, Minibiotus weinerorum and Acutuncus antarcticus. Other, unornamented eggs were also observed. The preservation of some of these eggs in exuviae allowed identification to at least genus. Significant variations were observed in egg abundance within the sediment of each lake, and in one lake a species (Dactylobiotus cf. ambiguus became locally extinct, probably as the result of penguin-associated eutrophication. Tardigrades generally did not become abundant for a considerable period after the lakes’ formation. The presence of an in-part endemic fauna is consistent with slow colonisation from Antarctic sources rather than wind transport from extra-continental sites. Tardigrade eggs appear to be abundant in high-latitude lake sediments, and greater use could be made of these records when evaluating tardigrade dynamics during the Holocene.

  16. Consequences of outbreeding on phenotypic plasticity in Drosophila mercatorum wings

    DEFF Research Database (Denmark)

    Krag, Kristian; Thomsen, Hans Paarup; Faurby, Søren

    2009-01-01

    A multivariate morphometric investigation was conducted on wings of two parthenogenetic Drosophila mercatorum strains and offspring (F1) of crosses between these parthenogenetic strains with highly inbred sexual individuals of the same species. The parental flies and F1 offspring were reared at t...

  17. Detection of cryptic species

    International Nuclear Information System (INIS)

    Cockburn, A.F.; Jensen, T.; Seawright, J.A.

    1998-01-01

    Morphologically similar cryptic species are common in insects. In Anopheles mosquitoes morphologically described species are complexes of cryptic species. Cryptic species are of great practical importance for two reasons: first, one or more species of the complex might not be a pest and control efforts directed at the complex as a whole would therefore be partly wasted; and second, genetic (and perhaps biological) control strategies directed against one species of the complex would not affect other species of the complex. At least one SIT effort has failed because the released sterile insect were of a different species and therefore did not mate with the wild insects being targeted. We use a multidisciplinary approach for detection of cryptic species complexes, focusing first on identifying variability in wild populations using RFLPs of mitochondrial and ribosomal RNA genes (mtDNA and rDNA); followed by confirmation using a variety of other techniques. For rapid identification of wild individuals of field collections, we use a DNA dot blot assay. DNA probes can be isolated by differential screening, however we are currently focusing on the sequencing of the rDNA extragenic spacers. These regions are repeated several hundred times per genome in mosquitoes and evolve rapidly. Molecular drive tends to keen the individual genes homogeneous within a species. (author)

  18. Detection of cryptic species

    Energy Technology Data Exchange (ETDEWEB)

    Cockburn, A F; Jensen, T; Seawright, J A [United States Dept. of Agriculture, Agricultural Research Service, Medical and Veterinary Entomology Research Lab., Gainesville, FL (United States)

    1998-01-01

    Morphologically similar cryptic species are common in insects. In Anopheles mosquitoes morphologically described species are complexes of cryptic species. Cryptic species are of great practical importance for two reasons: first, one or more species of the complex might not be a pest and control efforts directed at the complex as a whole would therefore be partly wasted; and second, genetic (and perhaps biological) control strategies directed against one species of the complex would not affect other species of the complex. At least one SIT effort has failed because the released sterile insect were of a different species and therefore did not mate with the wild insects being targeted. We use a multidisciplinary approach for detection of cryptic species complexes, focusing first on identifying variability in wild populations using RFLPs of mitochondrial and ribosomal RNA genes (mtDNA and rDNA); followed by confirmation using a variety of other techniques. For rapid identification of wild individuals of field collections, we use a DNA dot blot assay. DNA probes can be isolated by differential screening, however we are currently focusing on the sequencing of the rDNA extragenic spacers. These regions are repeated several hundred times per genome in mosquitoes and evolve rapidly. Molecular drive tends to keen the individual genes homogeneous within a species. (author). 11 refs, 2 figs, 2 tabs.

  19. Chapter 16: Species Diversity

    African Journals Online (AJOL)

    zargaran

    2012-05-03

    May 3, 2012 ... rarefaction method was recorded in Pardanan, with 28 oak gall wasps species. Furthermore, the highest amount of Gini-Simpson and Shannon entropy index were recorded in Sardasht, while the highest evenness was recorded in Shalmash. Differences in the local distribution of oak species, especially.

  20. The Origin of Species

    NARCIS (Netherlands)

    Darwin, Charles

    2005-01-01

    In The Origin of Species Darwin outlined his theory of evolution, which proposed that species had been evolving and differentiating over time under the influence of natural selection. On its publication it became hugely influential, bringing about a seismic shift in the scientific view of humanitys

  1. Aquatic species and habitats

    Science.gov (United States)

    Danny C. Lee; James R. Sedell; Bruce E. Rieman; Russell F. Thurow; Jack E. Williams

    1998-01-01

    Continuing human activities threaten the highly prized aquatic resources of the interior Columbia basin. Precipitous declines in native species, particularly Pacific salmon, and a large influx of introduced species have radically altered the composition and distribution of native fishes. Fortunately, areas of relatively high aquatic integrity remain, much of it on...

  2. Support your local species

    DEFF Research Database (Denmark)

    Stärk, Johanna

    Nearly a quarter of all animal species within the European Union are threatened with extinction. Protecting many of these species will require the full spectrum of conservation actions from in-situ to ex-situ management. Holding an estimated 44% of EU Red Listed terrestrial vertebrates, zoos hereby...

  3. Extragastric Helicobacter species

    DEFF Research Database (Denmark)

    On, Stephen L.W.; Hynes, S.; Wadstrom, T.

    2002-01-01

    The genus Helicobacter has expanded at a rapid pace and no fewer than 31 species have been named since the proposal of the genus in 1989. Of these 31 species, 22 are principally associated with extragastric niches and there is increasing interest in the role of these taxa in diseases of humans...... and animals. Substantial evidence attests to certain species playing a role in the pathogenesis of enteric, hepatic and biliary disorders and some taxa demonstrate zoonotic potential. The importance of extragastric Helicobacters is likely to be an important topic for research in the near future. Here...

  4. The species in primatology.

    Science.gov (United States)

    Groves, Colin

    2014-01-01

    Biologists of the late eighteenth and early nineteenth centuries all bandied about the term "species," but very rarely actually said what they meant by it. Often, however, one can get inside their thinking by piecing together some of their remarks. One of the most nearly explicit-appropriately, for the man who wrote a book called The Origin of Species - was Charles Darwin: "Practically, when a naturalist can unite two forms together by others having intermediate characters, he treats the one as a variety of the other… He later translated this into evolutionary terms: "Hereafter, we shall be compelled to acknowledge that the only distinction between species and well-marked varieties is, that the latter are known, or believed, to be connected at the present day by intermediate gradations, whereas species were formerly thus connected"(1:484-5.) Copyright © 2014 Wiley Periodicals, Inc.

  5. Hierarchical species distribution models

    Science.gov (United States)

    Hefley, Trevor J.; Hooten, Mevin B.

    2016-01-01

    Determining the distribution pattern of a species is important to increase scientific knowledge, inform management decisions, and conserve biodiversity. To infer spatial and temporal patterns, species distribution models have been developed for use with many sampling designs and types of data. Recently, it has been shown that count, presence-absence, and presence-only data can be conceptualized as arising from a point process distribution. Therefore, it is important to understand properties of the point process distribution. We examine how the hierarchical species distribution modeling framework has been used to incorporate a wide array of regression and theory-based components while accounting for the data collection process and making use of auxiliary information. The hierarchical modeling framework allows us to demonstrate how several commonly used species distribution models can be derived from the point process distribution, highlight areas of potential overlap between different models, and suggest areas where further research is needed.

  6. Endangered Species: Pesticide Restrictions

    Science.gov (United States)

    Our goal is to protect threatened and endangered species and their habitats, without placing unnecessary burden on agriculture and pesticide users. Pesticide limitations are developed to ensure safe use of pesticides in order to meet this goal.

  7. Threatened & Endangered Species Occurrences

    Data.gov (United States)

    Kansas Data Access and Support Center — The database consists of a single statewide coverage of location records for 54 species contained in the Kansas Natural Heritage Inventory database of the Kansas...

  8. Sub specie aeternitatis

    Directory of Open Access Journals (Sweden)

    Laura Gioeni

    2012-10-01

    Full Text Available Per delineare il rapporto tra etica ed estetica nell'architettura e rispondere alla domanda principale «che cosa è o dovrebbe essere un buon architetto?», il saggio discute la tesi di Wittgenstein secondo cui «l'opera d'arte è l'oggetto visto sub specie aeternitatis e la vita buona è il mondo visto sub specie aeternitatis. Questa è la connessione tra arte ed etica».

  9. Genomic definition of species

    Energy Technology Data Exchange (ETDEWEB)

    Crkvenjakov, R.; Drmanac, R.

    1991-07-01

    The subject of this paper is the definition of species based on the assumption that genome is the fundamental level for the origin and maintenance of biological diversity. For this view to be logically consistent it is necessary to assume the existence and operation of the new law which we call genome law. For this reason the genome law is included in the explanation of species phenomenon presented here even if its precise formulation and elaboration are left for the future. The intellectual underpinnings of this definition can be traced to Goldschmidt. We wish to explore some philosophical aspects of the definition of species in terms of the genome. The point of proposing the definition on these grounds is that any real advance in evolutionary theory has to be correct in both its philosophy and its science.

  10. Bounding species distribution models

    Directory of Open Access Journals (Sweden)

    Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

    2011-10-01

    Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

  11. Bounding Species Distribution Models

    Science.gov (United States)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  12. Aquatic Nuisance Species Locator

    Science.gov (United States)

    Data in this map has been collected by the United States Geological Survey's Nonindigenous Aquatic Species program located in Gainesville, Florida (http://nas.er.usgs.gov/default.aspx). This dataset may have some inaccuracies and is only current to June 15, 2012. The species identified in this dataset are not inclusive of all aquatic nuisance species, but rather a subset identified to be at risk for transport by recreational activities such as boating and angling. Additionally, the locations where organisims have been identified are also not inclusive and should be treated as a guide. Organisms are limited to the following: American bullfrog, Asian clam, Asian shore crab, Asian tunicate, Australian spotted jellyfish, Chinese mitten crab, New Zealand mudsnail, Colonial sea squirt, Alewife, Bighead carp, Black carp, Flathead catfish, Grass carp, Green crab, Lionfish, Northern snakehead, Quagga mussel, Round Goby, Ruffe, Rusty crayfish, Sea lamprey, Silver carp, Spiny water flea, Veined rapa whelk, Zebra mussel

  13. Man as a Species.

    Science.gov (United States)

    Solem, Alan; And Others

    Written in 1964, the document represents experimental material of the Anthropology Curriculum Study Project. The objectives of the project were to discuss the evolution of man as distinguished from the evolution of other species and as related to culture, and to emphasize human diversity. Three brief essays are presented. The first, "The…

  14. Coevolution of Symbiotic Species

    OpenAIRE

    Leok, Boon Tiong Melvin

    1996-01-01

    This paper will consider the coevolution of species which are symbiotic in their interaction. In particular, we shall analyse the interaction of squirrels and oak trees, and develop a mathematical framework for determining the coevolutionary equilibrium for consumption and production patterns.

  15. Behavioral facilitation of reproduction in sexual and unisexual whiptail lizards.

    OpenAIRE

    Crews, D; Grassman, M; Lindzey, J

    1986-01-01

    All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Mating behavior accomplishes the transfer of gametes and stimulates the coordination of reproductive activity of the male and female. Cnemidophorus uniparens, a parthenogenetic species, is believed to have resulted from the hybridization of two extant gonochoristic species, Cnemidophorus inornatus and Cnemidophorus gularis. C. uniparens regularly and reliably perform behavio...

  16. Positive feedback in species communities

    NARCIS (Netherlands)

    Gerla, D.J.

    2012-01-01

    Sometimes the eventual population densities in a species community depend on the initial densities or the arrival times of species. If arrival times determine species composition, a priority effect has occurred. Priority effects may occur if the species community exhibits alternative stable states

  17. The functional biogeography of species

    DEFF Research Database (Denmark)

    Carstensen, Daniel W.; Dalsgaard, Bo; Svenning, Jens-Christian

    2013-01-01

    Biogeographical systems can be analyzed as networks of species and geographical units. Within such a biogeographical network, individual species may differ fundamentally in their linkage pattern, and therefore hold different topological roles. To advance our understanding of the relationship betw...... to distributions at the local community level. We finally discuss how our biogeographical species roles may correspond to the stages of the taxon cycle and other prominent theories of species assembly.......Biogeographical systems can be analyzed as networks of species and geographical units. Within such a biogeographical network, individual species may differ fundamentally in their linkage pattern, and therefore hold different topological roles. To advance our understanding of the relationship...... between species traits and large-scale species distribution patterns in archipelagos, we use a network approach to classify birds as one of four biogeographical species roles: peripherals, connectors, module hubs, and network hubs. These roles are based upon the position of species within the modular...

  18. Autecology of broadleaved species

    OpenAIRE

    Gonin, Pierre; Larrieu, Laurent; Coello, Jaime; Marty, Pauline; Lestrade , Marine; Becquey, Jacques; Claessens, Hugues

    2013-01-01

    Anyone involved in timber production needs some knowledge of autecology. With the renewed interest in hardwoods in the last 20 years, they are increasingly being introduced by planting or encouraged in natural stands. The results in terms of growth have not always met foresters’ expectations, due to technical problems and especially because the species are not always suited to the different sites. While the principle of establishing hardwoods is not in question, it is important to be aware of...

  19. Prior indigenous technological species

    Science.gov (United States)

    Wright, Jason T.

    2018-01-01

    One of the primary open questions of astrobiology is whether there is extant or extinct life elsewhere the solar system. Implicit in much of this work is that we are looking for microbial or, at best, unintelligent life, even though technological artefacts might be much easier to find. Search for Extraterrestrial Intelligence (SETI) work on searches for alien artefacts in the solar system typically presumes that such artefacts would be of extrasolar origin, even though life is known to have existed in the solar system, on Earth, for eons. But if a prior technological, perhaps spacefaring, species ever arose in the solar system, it might have produced artefacts or other technosignatures that have survived to present day, meaning solar system artefact SETI provides a potential path to resolving astrobiology's question. Here, I discuss the origins and possible locations for technosignatures of such a prior indigenous technological species, which might have arisen on ancient Earth or another body, such as a pre-greenhouse Venus or a wet Mars. In the case of Venus, the arrival of its global greenhouse and potential resurfacing might have erased all evidence of its existence on the Venusian surface. In the case of Earth, erosion and, ultimately, plate tectonics may have erased most such evidence if the species lived Gyr ago. Remaining indigenous technosignatures might be expected to be extremely old, limiting the places they might still be found to beneath the surfaces of Mars and the Moon, or in the outer solar system.

  20. Estimating Effects of Species Interactions on Populations of Endangered Species.

    Science.gov (United States)

    Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

    2016-04-01

    Global change causes community composition to change considerably through time, with ever-new combinations of interacting species. To study the consequences of newly established species interactions, one available source of data could be observational surveys from biodiversity monitoring. However, approaches using observational data would need to account for niche differences between species and for imperfect detection of individuals. To estimate population sizes of interacting species, we extended N-mixture models that were developed to estimate true population sizes in single species. Simulations revealed that our model is able to disentangle direct effects of dominant on subordinate species from indirect effects of dominant species on detection probability of subordinate species. For illustration, we applied our model to data from a Swiss amphibian monitoring program and showed that sizes of expanding water frog populations were negatively related to population sizes of endangered yellow-bellied toads and common midwife toads and partly of natterjack toads. Unlike other studies that analyzed presence and absence of species, our model suggests that the spread of water frogs in Central Europe is one of the reasons for the decline of endangered toad species. Thus, studying population impacts of dominant species on population sizes of endangered species using data from biodiversity monitoring programs should help to inform conservation policy and to decide whether competing species should be subject to population management.

  1. CHROMOSOMES OF WOODY SPECIES

    Directory of Open Access Journals (Sweden)

    Julio R Daviña

    2000-01-01

    Full Text Available Chromosome numbers of nine subtropical woody species collected in Argentina and Paraguay are reported. The counts tor Coutarea hexandra (2n=52, Inga vera subsp. affinis 2n=26 (Fabaceae and Chorisia speciosa 2n=86 (Bombacaceae are reported for the first time. The chromosome number given for Inga semialata 2n=52 is a new cytotype different from the previously reported. Somatic chromosome numbers of the other taxa studied are: Sesbania punicea 2n=12, S. virgata 2n=12 and Pilocarpus pennatifolius 2n=44 from Argentina

  2. Save Our Species: Protecting Endangered Species from Pesticides.

    Science.gov (United States)

    Environmental Protection Agency, Washington, DC.

    This full-size poster profiles 11 wildlife species that are endangered. Color illustrations of animals and plants are accompanied by narrative describing their habitats and reasons for endangerment. The reverse side of the poster contains information on the Endangered Species Act, why protecting endangered and threatened species is important, how…

  3. New species of Malaysian ferns

    NARCIS (Netherlands)

    Holttum, R.E.

    1962-01-01

    The present paper includes descriptions of several new species of ferns found among recent collections from various parts of Malaysia; also two new combinations of names of species which are of interest on account of their taxonomic history.

  4. Endangered Species Act Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Critical habitat (CH) is designated for the survival and recovery of species listed as threatened or endangered under the Endangered Species Act (ESA). Critical...

  5. New Malesian species of Viscaceae

    NARCIS (Netherlands)

    Barlow, Bryan A.

    1996-01-01

    Three new Malesian species of Viscaceae are described. Ginalloa flagellaris Barlow is distinguished as a species from New Guinea and New Britain, previously included within G. arnottiana Korthals. Viscum exile Barlow is recognized as a new species endemic to Celebes, related to V. ovalifolium.

  6. Lichen species preference by reindeer

    Energy Technology Data Exchange (ETDEWEB)

    Holleman, D F; Luick, J R

    1977-08-01

    The preference by reindeer for five species of lichens commonly found on Central Alaska rangelands was tested under controlled laboratory conditions. Results indicate that reindeer are strongly selective species in their lichen grazing habits. The five tested species ranged as follows in order of decreasing acceptibility: Caldonia alpestris, C. rangiferina, Stereocaulon paschale, Cetraria richardsonii, and Peltigera aphthosa.

  7. 75 FR 78974 - Endangered Species

    Science.gov (United States)

    2010-12-17

    ...-XA086 Endangered Species AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and... the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.) and the regulations governing the taking, importing, and exporting of endangered and threatened species (50 CFR 222-226). Permit...

  8. California Endangered Species Resource Guide.

    Science.gov (United States)

    California State Dept. of Education, Los Angeles.

    This document was developed in response to California Senate Bill No. 885, "The Endangered Species Education Project," that called for a statewide program in which schools adopt a local endangered species, research past and current efforts to preserve the species' habitat, develop and implement an action plan to educate the community…

  9. 76 FR 2348 - Endangered Species

    Science.gov (United States)

    2011-01-13

    .... 15596] Endangered Species AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and... requested permit has been issued under the authority of the Endangered Species Act of 1973, as amended (ESA... endangered and threatened species (50 CFR parts 222-226). The North Carolina Aquarium at Fort Fisher has been...

  10. Electrosmog and species conservation

    Energy Technology Data Exchange (ETDEWEB)

    Balmori, Alfonso, E-mail: abalmorimartinez@gmail.com

    2014-10-15

    Despite the widespread use of wireless telephone networks around the world, authorities and researchers have paid little attention to the potential harmful effects of mobile phone radiation on wildlife. This paper briefly reviews the available scientific information on this topic and recommends further studies and specific lines of research to confirm or refute the experimental results to date. Controls must be introduced and technology rendered safe for the environment, particularly, threatened species. - Highlights: • Studies have shown effects in both animals and plants. • Two thirds of the studies reported ecological effects. • There is little research in this area and further research is needed. • The technology must be safe. • Controls should be introduced to mitigate the possible effects.

  11. Management of invasive species

    DEFF Research Database (Denmark)

    Schou, Jesper Sølver; Jensen, Frank

    impact of the establishment of this invasive species is a substantial increase in the number of allergy cases, which we use as a measure of the physical damage. As valuation methods, we use both the cost-of-illness method and the benefit transfer method to quantify the total gross benefits of the two...... policy actions. Based on the idea of an invasion function, we identify the total and average net benefit under both prevention and mitigation. For both policy actions, the total and average net benefits are significantly positive irrespective of the valuation method used; therefore, both prevention...... and mitigation are beneficial policy actions. However, the total and average net benefits under mitigation are larger than the benefits under prevention, implying that the former policy action is more beneficial. Despite this result, we conclude that prevention, not mitigation, shall be used because...

  12. Prices and species diversity

    DEFF Research Database (Denmark)

    Sauer, Johannes

    of biodiversity and the appropriate incorporation in stochastic fron-tier models to achieve more realistic measures of production efficiency. We use the empirical example of tobacco production drawing from as well as affecting species diversity in the surrounding forests. We apply a shadow profit distance......In recent decades a significant amount of literature has been produced concerned with establishing a link between production efficiency and environmental efficiency with respect to quantitative modelling. This has been mainly addressed by focusing on the incorporation of undesirable outputs...... or the incorporation of environmentally det-rimental inputs. However, while the debate with respect to linear programming based DEA modelling is already at an advanced stage the corresponding one with respect to stochastic frontier modelling still needs considerable efforts. This contribution fo-cuses on the case...

  13. Reactive Oxygen Species

    DEFF Research Database (Denmark)

    Franchina, Davide G.; Dostert, Catherine; Brenner, Dirk

    2018-01-01

    T cells are a central component of defenses against pathogens and tumors. Their effector functions are sustained by specific metabolic changes that occur upon activation, and these have been the focus of renewed interest. Energy production inevitably generates unwanted products, namely reactive...... and transcription factors, influencing the outcome of the T cell response. We discuss here how ROS can directly fine-tune metabolism and effector functions of T cells....... oxygen species (ROS), which have long been known to trigger cell death. However, there is now evidence that ROS also act as intracellular signaling molecules both in steady-state and upon antigen recognition. The levels and localization of ROS contribute to the redox modeling of effector proteins...

  14. Introduced species as evolutionary traps

    Science.gov (United States)

    Schlaepfer, Martin A.; Sherman, P.W.; Blossey, B.; Runge, M.C.

    2005-01-01

    Invasive species can alter environments in such a way that normal behavioural decision-making rules of native species are no longer adaptive. The evolutionary trap concept provides a useful framework for predicting and managing the impact of harmful invasive species. We discuss how native species can respond to changes in their selective regime via evolution or learning. We also propose novel management strategies to promote the long-term co-existence of native and introduced species in cases where the eradication of the latter is either economically or biologically unrealistic.

  15. Insular species swarm goes underground

    DEFF Research Database (Denmark)

    P. S. Reboleira, Ana Sofia; Enghoff, Henrik

    2014-01-01

    Two new species of the genus Cylindroiulus Verhoeff, 1894, C. julesvernei and C. oromii, are described from the subterranean ecosystem of Madeira Island, Portugal. Species are illustrated with photographs and diagrammatic drawings. The new species belong to the Cylindroiulus madeirae......-group, an insular species swarm distributed in the archipelagos of Madeira and the Canary Islands. We discuss the differences between the new species and their relatives and present information on the subterranean environment of Madeira. An updated overview of the subterranean biodiversity of millipedes...

  16. Ring species as demonstrations of the continuum of species formation

    DEFF Research Database (Denmark)

    Pereira, Ricardo José Do Nascimento; Wake, David B.

    2015-01-01

    In the mid-20th century, Ernst Mayr (1942) and Theodosius Dobzhansky (1958) championed the significance of 'circular overlaps' or 'ring species' as the perfect demonstration of the gradual nature of species formation. As an ancestral species expands its range, wrapping around a geographic barrier......? What conditions favour their formation? Modelling studies have attempted to address these knowledge gaps by estimating the biological parameters that result in stable ring species (Martins et al. 2013), and determining the necessary topographic parameters of the barriers encircled (Monahan et al. 2012......). However, any generalization is undermined by a major limitation: only a handful of ring species are known to exist in nature. In addition, many of them have been broken into multiple species presumed to be evolving independently, usually obscuring the evolutionary dynamics that generate diversity. A paper...

  17. Species of Wadicosa (Araneae, Lycosidae): a new species from Madagascar.

    Science.gov (United States)

    Kronestedt, Torbjörn

    2017-05-10

    Since establishing the wolf spider genus Wadicosa Zyuzin, 1985 (Zyuzin 1985), eleven species have been accepted in it, either by transfer from Lycosa Latreille, 1804 or Pardosa C.L. Koch, 1847 or by original designation (WSC 2017). However, according to Kronestedt (1987), additional species wait to be formally transferred to Wadicosa. The genus is restricted to the Old World, with one species, Wadicosa jocquei Kronestedt, 2015, recently described from Madagascar and surrounding islands.

  18. Native species that can replace exotic species in landscaping

    Directory of Open Access Journals (Sweden)

    Elisabeth Regina Tempel Stumpf

    2015-08-01

    Full Text Available Beyond aesthetics, the contemporary landscaping intends to provide other benefits for humans and environment, especially related to the environmental quality of urban spaces and conservation of the species. A trend in this direction is the reduction in the use of exotic plants in their designs, since, over time, they can become agents of replacement of native flora, as it has occurred in Rio Grande do Sul with many species introduced by settlers. However, the use of exotic species is unjustifiable, because the flora diversity of the Bioma Pampa offers many native species with appropriate features to the ornamental use. The commercial cultivation and the implantation of native species in landscaped areas constitute innovations for plant nurseries and landscapers and can provide a positive reduction in extractivism, contributing to dissemination, exploitation and preservation of native flora, and also decrease the impact of chemical products on environment. So, this work intends to identify native species of Bioma Pampa with features and uses similar to the most used exotic species at Brazilian landscaping. The species were selected from consulting books about native plants of Bioma Pampa and plants used at Brazilian landscaping, considering the similarity on habit and architecture, as well as characteristics of leafs, flowers and/or fruits and environmental conditions of occurrence and cultivation. There were identified 34 native species able to properly replace exotic species commonly used. The results show that many native species of Bioma Pampa have interesting ornamental features to landscape gardening, allowing them to replace exotic species that are traditionally cultivated.

  19. Population genetics and cryptic species

    International Nuclear Information System (INIS)

    McPheron, Bruce A.

    2000-01-01

    Does the definition of a species matter for pest management purposes? Taxonomists provide us with tools - usually morphological characters - to identify a group of organisms that we call a species. The implication of this identification is that all of the individuals that fit the provided description are members of the species in question. The taxonomists have considered the range of variation among individuals in defining the species, but this variation is often forgotten when we take the concept of species to the level of management. Just as there is morphological variation among individuals, there is also variation in practically any character we might imagine, which has implications for the short and long term success of our management tactics. The rich literature on insecticide resistance should be a constant reminder of the fact that the pressure on pest survival and reproduction applied by our management approaches frequently leads to evolutionary changes within the pest species. The degree of variation within a particular species is a defining characteristic of that species. This level of variability may have very important implications for successful management, so it is very important to measure variation and, whenever possible, the genetic basis of that variation, in a target species. Population genetic approaches can provide evidence of genetic structure (or lack thereof) among populations of a species. These types of data can be used to discuss the movement of pest populations on a local or global scale. In other cases, we may have a complex of species that share some, but not all, characteristics. Species complexes that share morphological characters (i.e., cannot be easily distinguished) but not biological characters are referred to as sibling or cryptic species

  20. Confronting species distribution model predictions with species functional traits.

    Science.gov (United States)

    Wittmann, Marion E; Barnes, Matthew A; Jerde, Christopher L; Jones, Lisa A; Lodge, David M

    2016-02-01

    Species distribution models are valuable tools in studies of biogeography, ecology, and climate change and have been used to inform conservation and ecosystem management. However, species distribution models typically incorporate only climatic variables and species presence data. Model development or validation rarely considers functional components of species traits or other types of biological data. We implemented a species distribution model (Maxent) to predict global climate habitat suitability for Grass Carp (Ctenopharyngodon idella). We then tested the relationship between the degree of climate habitat suitability predicted by Maxent and the individual growth rates of both wild (N = 17) and stocked (N = 51) Grass Carp populations using correlation analysis. The Grass Carp Maxent model accurately reflected the global occurrence data (AUC = 0.904). Observations of Grass Carp growth rate covered six continents and ranged from 0.19 to 20.1 g day(-1). Species distribution model predictions were correlated (r = 0.5, 95% CI (0.03, 0.79)) with observed growth rates for wild Grass Carp populations but were not correlated (r = -0.26, 95% CI (-0.5, 0.012)) with stocked populations. Further, a review of the literature indicates that the few studies for other species that have previously assessed the relationship between the degree of predicted climate habitat suitability and species functional traits have also discovered significant relationships. Thus, species distribution models may provide inferences beyond just where a species may occur, providing a useful tool to understand the linkage between species distributions and underlying biological mechanisms.

  1. Balance of bacterial species in the gut

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Balance of bacterial species in the gut. Protective. Lactobacillus species. Bifidobacterium species. Selected E. coli. Saccharomyces boulardii. Clostridium butyricum.

  2. Quantifying the invasiveness of species

    Directory of Open Access Journals (Sweden)

    Robert Colautti

    2014-04-01

    Full Text Available The success of invasive species has been explained by two contrasting but non-exclusive views: (i intrinsic factors make some species inherently good invaders; (ii species become invasive as a result of extrinsic ecological and genetic influences such as release from natural enemies, hybridization or other novel ecological and evolutionary interactions. These viewpoints are rarely distinguished but hinge on distinct mechanisms leading to different management scenarios. To improve tests of these hypotheses of invasion success we introduce a simple mathematical framework to quantify the invasiveness of species along two axes: (i interspecific differences in performance among native and introduced species within a region, and (ii intraspecific differences between populations of a species in its native and introduced ranges. Applying these equations to a sample dataset of occurrences of 1,416 plant species across Europe, Argentina, and South Africa, we found that many species are common in their native range but become rare following introduction; only a few introduced species become more common. Biogeographical factors limiting spread (e.g. biotic resistance, time of invasion therefore appear more common than those promoting invasion (e.g. enemy release. Invasiveness, as measured by occurrence data, is better explained by inter-specific variation in invasion potential than biogeographical changes in performance. We discuss how applying these comparisons to more detailed performance data would improve hypothesis testing in invasion biology and potentially lead to more efficient management strategies.

  3. Uncommon Species and Other Features

    Data.gov (United States)

    Vermont Center for Geographic Information — The Vermont Fish and Wildlife Department's Natural Heritage Inventory (NHI) maintains a database of uncommon, rare, threatened and endangered species and natural...

  4. Incorporating Context Dependency of Species Interactions in Species Distribution Models.

    Science.gov (United States)

    Lany, Nina K; Zarnetske, Phoebe L; Gouhier, Tarik C; Menge, Bruce A

    2017-07-01

    Species distribution models typically use correlative approaches that characterize the species-environment relationship using occurrence or abundance data for a single species. However, species distributions are determined by both abiotic conditions and biotic interactions with other species in the community. Therefore, climate change is expected to impact species through direct effects on their physiology and indirect effects propagated through their resources, predators, competitors, or mutualists. Furthermore, the sign and strength of species interactions can change according to abiotic conditions, resulting in context-dependent species interactions that may change across space or with climate change. Here, we incorporated the context dependency of species interactions into a dynamic species distribution model. We developed a multi-species model that uses a time-series of observational survey data to evaluate how abiotic conditions and species interactions affect the dynamics of three rocky intertidal species. The model further distinguishes between the direct effects of abiotic conditions on abundance and the indirect effects propagated through interactions with other species. We apply the model to keystone predation by the sea star Pisaster ochraceus on the mussel Mytilus californianus and the barnacle Balanus glandula in the rocky intertidal zone of the Pacific coast, USA. Our method indicated that biotic interactions between P. ochraceus and B. glandula affected B. glandula dynamics across >1000 km of coastline. Consistent with patterns from keystone predation, the growth rate of B. glandula varied according to the abundance of P. ochraceus in the previous year. The data and the model did not indicate that the strength of keystone predation by P. ochraceus varied with a mean annual upwelling index. Balanus glandula cover increased following years with high phytoplankton abundance measured as mean annual chlorophyll-a. M. californianus exhibited the same

  5. Previously unknown species of Aspergillus.

    Science.gov (United States)

    Gautier, M; Normand, A-C; Ranque, S

    2016-08-01

    The use of multi-locus DNA sequence analysis has led to the description of previously unknown 'cryptic' Aspergillus species, whereas classical morphology-based identification of Aspergillus remains limited to the section or species-complex level. The current literature highlights two main features concerning these 'cryptic' Aspergillus species. First, the prevalence of such species in clinical samples is relatively high compared with emergent filamentous fungal taxa such as Mucorales, Scedosporium or Fusarium. Second, it is clearly important to identify these species in the clinical laboratory because of the high frequency of antifungal drug-resistant isolates of such Aspergillus species. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been shown to enable the identification of filamentous fungi with an accuracy similar to that of DNA sequence-based methods. As MALDI-TOF MS is well suited to the routine clinical laboratory workflow, it facilitates the identification of these 'cryptic' Aspergillus species at the routine mycology bench. The rapid establishment of enhanced filamentous fungi identification facilities will lead to a better understanding of the epidemiology and clinical importance of these emerging Aspergillus species. Based on routine MALDI-TOF MS-based identification results, we provide original insights into the key interpretation issues of a positive Aspergillus culture from a clinical sample. Which ubiquitous species that are frequently isolated from air samples are rarely involved in human invasive disease? Can both the species and the type of biological sample indicate Aspergillus carriage, colonization or infection in a patient? Highly accurate routine filamentous fungi identification is central to enhance the understanding of these previously unknown Aspergillus species, with a vital impact on further improved patient care. Copyright © 2016 European Society of Clinical Microbiology and

  6. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.

  7. 76 FR 74778 - Endangered Species

    Science.gov (United States)

    2011-12-01

    .... 16439] Endangered Species AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and... has been issued under the authority of the Endangered Species Act of 1973, as amended (ESA; 16 U.S.C. 1531 et seq.) and the regulations governing the taking, importing, and exporting of endangered and...

  8. [Yeast species in vulvovaginitis candidosa].

    Science.gov (United States)

    Nemes-Nikodém, Éva; Tamási, Béla; Mihalik, Noémi; Ostorházi, Eszter

    2015-01-04

    Vulvovaginal candidiasis is the most common mycosis, however, the available information about antifungal susceptibilities of these yeasts is limited. To compare the gold standard fungal culture with a new molecular identification method and report the incidence of yeast species in vulvovaginitis candidosa. The authors studied 370 yeasts isolated from vulvovaginal candidiasis and identified them by phenotypic and molecular methods. The most common species was Candida albicans (85%), followed by Candida glabrata, and other Candida species. At present there are no recommendations for the evaluation of antifungal susceptibility of pathogenic fungal species occurring in vulvovaginal candidiasis and the natural antifungal resistance of the different species is known only. Matrix Assisted Laser Desorption Ionization Time of Flight identification can be used to differentiate the fluconazole resistant Candida dubliniensis and the sensitive Candida albicans strains.

  9. Enolonium Species-Umpoled Enolates

    DEFF Research Database (Denmark)

    Arava, Shlomy; Kumar, Jayprakash N.; Maksymenko, Shimon

    2017-01-01

    Enolonium species/iodo(III) enolates of carbonyl compounds have been suggested to be intermediates in a wide variety of hypervalent iodine induced chemical transformations of ketones, including α-C-O, α-C-N, α-C-C, and alpha-carbon- halide bond formation, but they have never been characterized. We...... report that these elusive umpoled enolates may be made as discrete species that are stable for several minutes at-78 degrees C, and report the first spectroscopic identification of such species. It is shown that enolonium species are direct intermediates in C-O, C-N, C-Cl, and C-C bond forming reactions....... Our results open up chemical space for designing a variety of new transformations. We showcase the ability of enolonium species to react with prenyl, crotyl, cinnamyl, and allyl silanes with absolute regioselectivity in up to 92% yield....

  10. Species concepts, species delimitation and the inherent limitations

    Indian Academy of Sciences (India)

    Frank Zachos

    synchrony and to sexually reproducing organisms would not be a problem anymore ... approach to species delimitation that combines genetic data with .... The datasets or algorithms could then be modified so that the groups yielded conform.

  11. Genome Sequences of Oryza Species

    KAUST Repository

    Kumagai, Masahiko; Tanaka, Tsuyoshi; Ohyanagi, Hajime; Hsing, Yue-Ie C.; Itoh, Takeshi

    2018-01-01

    This chapter summarizes recent data obtained from genome sequencing, annotation projects, and studies on the genome diversity of Oryza sativa and related Oryza species. O. sativa, commonly known as Asian rice, is the first monocot species whose complete genome sequence was deciphered based on physical mapping by an international collaborative effort. This genome, along with its accurate and comprehensive annotation, has become an indispensable foundation for crop genomics and breeding. With the development of innovative sequencing technologies, genomic studies of O. sativa have dramatically increased; in particular, a large number of cultivars and wild accessions have been sequenced and compared with the reference rice genome. Since de novo genome sequencing has become cost-effective, the genome of African cultivated rice, O. glaberrima, has also been determined. Comparative genomic studies have highlighted the independent domestication processes of different rice species, but it also turned out that Asian and African rice share a common gene set that has experienced similar artificial selection. An international project aimed at constructing reference genomes and examining the genome diversity of wild Oryza species is currently underway, and the genomes of some species are publicly available. This project provides a platform for investigations such as the evolution, development, polyploidization, and improvement of crops. Studies on the genomic diversity of Oryza species, including wild species, should provide new insights to solve the problem of growing food demands in the face of rapid climatic changes.

  12. Genome Sequences of Oryza Species

    KAUST Repository

    Kumagai, Masahiko

    2018-02-14

    This chapter summarizes recent data obtained from genome sequencing, annotation projects, and studies on the genome diversity of Oryza sativa and related Oryza species. O. sativa, commonly known as Asian rice, is the first monocot species whose complete genome sequence was deciphered based on physical mapping by an international collaborative effort. This genome, along with its accurate and comprehensive annotation, has become an indispensable foundation for crop genomics and breeding. With the development of innovative sequencing technologies, genomic studies of O. sativa have dramatically increased; in particular, a large number of cultivars and wild accessions have been sequenced and compared with the reference rice genome. Since de novo genome sequencing has become cost-effective, the genome of African cultivated rice, O. glaberrima, has also been determined. Comparative genomic studies have highlighted the independent domestication processes of different rice species, but it also turned out that Asian and African rice share a common gene set that has experienced similar artificial selection. An international project aimed at constructing reference genomes and examining the genome diversity of wild Oryza species is currently underway, and the genomes of some species are publicly available. This project provides a platform for investigations such as the evolution, development, polyploidization, and improvement of crops. Studies on the genomic diversity of Oryza species, including wild species, should provide new insights to solve the problem of growing food demands in the face of rapid climatic changes.

  13. Species interactions and plant polyploidy.

    Science.gov (United States)

    Segraves, Kari A; Anneberg, Thomas J

    2016-07-01

    Polyploidy is a common mode of speciation that can have far-reaching consequences for plant ecology and evolution. Because polyploidy can induce an array of phenotypic changes, there can be cascading effects on interactions with other species. These interactions, in turn, can have reciprocal effects on polyploid plants, potentially impacting their establishment and persistence. Although there is a wealth of information on the genetic and phenotypic effects of polyploidy, the study of species interactions in polyploid plants remains a comparatively young field. Here we reviewed the available evidence for how polyploidy may impact many types of species interactions that range from mutualism to antagonism. Specifically, we focused on three main questions: (1) Does polyploidy directly cause the formation of novel interactions not experienced by diploids, or does it create an opportunity for natural selection to then form novel interactions? (2) Does polyploidy cause consistent, predictable changes in species interactions vs. the evolution of idiosyncratic differences? (3) Does polyploidy lead to greater evolvability in species interactions? From the scarce evidence available, we found that novel interactions are rare but that polyploidy can induce changes in pollinator, herbivore, and pathogen interactions. Although further tests are needed, it is likely that selection following whole-genome duplication is important in all types of species interaction and that there are circumstances in which polyploidy can enhance the evolvability of interactions with other species. © 2016 Botanical Society of America.

  14. Scale dependence in species turnover reflects variance in species occupancy.

    Science.gov (United States)

    McGlinn, Daniel J; Hurlbert, Allen H

    2012-02-01

    Patterns of species turnover may reflect the processes driving community dynamics across scales. While the majority of studies on species turnover have examined pairwise comparison metrics (e.g., the average Jaccard dissimilarity), it has been proposed that the species-area relationship (SAR) also offers insight into patterns of species turnover because these two patterns may be analytically linked. However, these previous links only apply in a special case where turnover is scale invariant, and we demonstrate across three different plant communities that over 90% of the pairwise turnover values are larger than expected based on scale-invariant predictions from the SAR. Furthermore, the degree of scale dependence in turnover was negatively related to the degree of variance in the occupancy frequency distribution (OFD). These findings suggest that species turnover diverges from scale invariance, and as such pairwise turnover and the slope of the SAR are not redundant. Furthermore, models developed to explain the OFD should be linked with those developed to explain species turnover to achieve a more unified understanding of community structure.

  15. Species-area relationships are controlled by species traits.

    Science.gov (United States)

    Franzén, Markus; Schweiger, Oliver; Betzholtz, Per-Eric

    2012-01-01

    The species-area relationship (SAR) is one of the most thoroughly investigated empirical relationships in ecology. Two theories have been proposed to explain SARs: classical island biogeography theory and niche theory. Classical island biogeography theory considers the processes of persistence, extinction, and colonization, whereas niche theory focuses on species requirements, such as habitat and resource use. Recent studies have called for the unification of these two theories to better explain the underlying mechanisms that generates SARs. In this context, species traits that can be related to each theory seem promising. Here we analyzed the SARs of butterfly and moth assemblages on islands differing in size and isolation. We tested whether species traits modify the SAR and the response to isolation. In addition to the expected overall effects on the area, traits related to each of the two theories increased the model fit, from 69% up to 90%. Steeper slopes have been shown to have a particularly higher sensitivity to area, which was indicated by species with restricted range (slope = 0.82), narrow dietary niche (slope= 0.59), low abundance (slope= 0.52), and low reproductive potential (slope = 0.51). We concluded that considering species traits by analyzing SARs yields considerable potential for unifying island biogeography theory and niche theory, and that the systematic and predictable effects observed when considering traits can help to guide conservation and management actions.

  16. Multiple mechanisms enable invasive species to suppress native species.

    Science.gov (United States)

    Bennett, Alison E; Thomsen, Meredith; Strauss, Sharon Y

    2011-07-01

    Invasive plants represent a significant threat to ecosystem biodiversity. To decrease the impacts of invasive species, a major scientific undertaking of the last few decades has been aimed at understanding the mechanisms that drive invasive plant success. Most studies and theories have focused on a single mechanism for predicting the success of invasive plants and therefore cannot provide insight as to the relative importance of multiple interactions in predicting invasive species' success. We examine four mechanisms that potentially contribute to the success of invasive velvetgrass Holcus lanatus: direct competition, indirect competition mediated by mammalian herbivores, interference competition via allelopathy, and indirect competition mediated by changes in the soil community. Using a combination of field and greenhouse approaches, we focus on the effects of H. lanatus on a common species in California coastal prairies, Erigeron glaucus, where the invasion is most intense. We found that H. lanatus had the strongest effects on E. glaucus via direct competition, but it also influenced the soil community in ways that feed back to negatively influence E. glaucus and other native species after H. lanatus removal. This approach provided evidence for multiple mechanisms contributing to negative effects of invasive species, and it identified when particular strategies were most likely to be important. These mechanisms can be applied to eradication of H. lanatus and conservation of California coastal prairie systems, and they illustrate the utility of an integrated set of experiments for determining the potential mechanisms of invasive species' success.

  17. Evolution of mutualism between species

    Energy Technology Data Exchange (ETDEWEB)

    Post, W.M.; Travis, C.C.; DeAngelis, D.L.

    1980-01-01

    Recent theoretical work on mutualism, the interaction between species populations that is mutually beneficial, is reviewed. Several ecological facts that should be addressed in the construction of dynamic models for mutualism are examined. Basic terminology is clarified. (PSB)

  18. Phase Two Protected Species Valuation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nonmarket valuation research has produced economic value estimates for a variety of threatened, endangered, and rare species around the world. Although over 40 value...

  19. 76 FR 1405 - Endangered Species

    Science.gov (United States)

    2011-01-10

    ... the understanding of the pelagic ecology of these species and allow more reliable assessments of... permit: (1) Was applied for in good faith, (2) will not operate to the disadvantage of such endangered or...

  20. Infrared spectra of mineral species

    CERN Document Server

    Chukanov, Nikita V

    2014-01-01

    This book details more than 3,000 IR spectra of more than 2,000 mineral species collected during last 30 years. It features full descriptions and analytical data of each sample for which IR spectrum was obtained.

  1. THE USE OF CASSAVA SPECIES

    African Journals Online (AJOL)

    User

    The plant is propagated from mature stems, which .... USE OF CASSAVA SPECIES AND ALUM IN WASTE WATER TREATMENT, .... acidity, total suspended solids, dissolved oxygen and ..... Rural Areas, MSc Thesis, Department of Water.

  2. Achromobacter species in cystic fibrosis

    DEFF Research Database (Denmark)

    Hansen, C R; Pressler, T; Ridderberg, W

    2013-01-01

    Achromobacter species leads to chronic infection in an increasing number of CF patients. We report 2 cases of Achromobacter ruhlandii cross-infection between patients after well-described indirect contact....

  3. Species Typing in Dermal Leishmaniasis

    Science.gov (United States)

    Dujardin, Jean-Claude

    2015-01-01

    SUMMARY Leishmania is an infectious protozoan parasite related to African and American trypanosomes. All Leishmania species that are pathogenic to humans can cause dermal disease. When one is confronted with cutaneous leishmaniasis, identification of the causative species is relevant in both clinical and epidemiological studies, case management, and control. This review gives an overview of the currently existing and most used assays for species discrimination, with a critical appraisal of the limitations of each technique. The consensus taxonomy for the genus is outlined, including debatable species designations. Finally, a numerical literature analysis is presented that describes which methods are most used in various countries and regions in the world, and for which purposes. PMID:25672782

  4. The Candida Pathogenic Species Complex

    Science.gov (United States)

    Turner, Siobhán A.; Butler, Geraldine

    2014-01-01

    Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity. PMID:25183855

  5. Phase One Protected Species Valuation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Nonmarket valuation research has produced economic value estimates for a variety of threatened, endangered, and rare species around the world. Although over 40 value...

  6. Theoretical microbial ecology without species

    Science.gov (United States)

    Tikhonov, Mikhail

    2017-09-01

    Ecosystems are commonly conceptualized as networks of interacting species. However, partitioning natural diversity of organisms into discrete units is notoriously problematic and mounting experimental evidence raises the intriguing question whether this perspective is appropriate for the microbial world. Here an alternative formalism is proposed that does not require postulating the existence of species as fundamental ecological variables and provides a naturally hierarchical description of community dynamics. This formalism allows approaching the species problem from the opposite direction. While the classical models treat a world of imperfectly clustered organism types as a perturbation around well-clustered species, the presented approach allows gradually adding structure to a fully disordered background. The relevance of this theoretical construct for describing highly diverse natural ecosystems is discussed.

  7. Species delimitation in the Stenocereus griseus (Cactaceae) species complex reveals a new species, S. huastecorum.

    Science.gov (United States)

    Alvarado-Sizzo, Hernán; Casas, Alejandro; Parra, Fabiola; Arreola-Nava, Hilda Julieta; Terrazas, Teresa; Sánchez, Cristian

    2018-01-01

    The Stenocereus griseus species complex (SGSC) has long been considered taxonomically challenging because the number of taxa belonging to the complex and their geographical boundaries remain poorly understood. Bayesian clustering and genetic distance-based methods were used based on nine microsatellite loci in 377 individuals of three main putative species of the complex. The resulting genetic clusters were assessed for ecological niche divergence and areolar morphology, particularly spination patterns. We based our species boundaries on concordance between genetic, ecological, and morphological data, and were able to resolve four species, three of them corresponding to S. pruinosus from central Mexico, S. laevigatus from southern Mexico, and S. griseus from northern South America. A fourth species, previously considered to be S. griseus and commonly misidentified as S. pruinosus in northern Mexico showed significant genetic, ecological, and morphological differentiation suggesting that it should be considered a new species, S. huastecorum, which we describe here. We show that population genetic analyses, ecological niche modeling, and morphological studies are complementary approaches for delimiting species in taxonomically challenging plant groups such as the SGSC.

  8. Species delimitation in the Stenocereus griseus (Cactaceae species complex reveals a new species, S. huastecorum.

    Directory of Open Access Journals (Sweden)

    Hernán Alvarado-Sizzo

    Full Text Available The Stenocereus griseus species complex (SGSC has long been considered taxonomically challenging because the number of taxa belonging to the complex and their geographical boundaries remain poorly understood. Bayesian clustering and genetic distance-based methods were used based on nine microsatellite loci in 377 individuals of three main putative species of the complex. The resulting genetic clusters were assessed for ecological niche divergence and areolar morphology, particularly spination patterns. We based our species boundaries on concordance between genetic, ecological, and morphological data, and were able to resolve four species, three of them corresponding to S. pruinosus from central Mexico, S. laevigatus from southern Mexico, and S. griseus from northern South America. A fourth species, previously considered to be S. griseus and commonly misidentified as S. pruinosus in northern Mexico showed significant genetic, ecological, and morphological differentiation suggesting that it should be considered a new species, S. huastecorum, which we describe here. We show that population genetic analyses, ecological niche modeling, and morphological studies are complementary approaches for delimiting species in taxonomically challenging plant groups such as the SGSC.

  9. Species selection for smallholder aquaculture

    OpenAIRE

    Brummett, R.E.

    1996-01-01

    Systems for selection of species for smallholder aquaculture are presented. These are: food fits; management decisions; and economic criteria. Food fits suggests categorizing pond food resources into a few categories based loosely on the instrinsic traits of food which effect their selectivity by predators. Using management decision techniques, potential polycultures might also be compared with each other and with monoculture. Under economic criteria (and for species known in local markets), ...

  10. Endangered Lilium Species of Turkey

    Directory of Open Access Journals (Sweden)

    Sevim Demir

    2018-01-01

    Full Text Available Turkey, which is among the major gene centers of the world and has a special place in plant genetic diversity. However, many plant genetic resources, including geophytes, are under genetic erosion because of the environmental and other problems and therefore face with the danger of extinction. Lilium ciliatum is endemic to North East Anatolia. IUCN (International Union for the Conservation of Natural Resources Red List Category of this species is Endangered (EN. Lilium ciliatum naturally grown in Zigana pass, Bayburt, Trabzon, Bulancak, Giresun and Gümüşhane is endangered and major threats of L. ciliatum are road construction and human disturbance related to ecotourism and recreation. It was reported that Lilium carniolicum naturally grown in Turkey is endangered although it isn’t in the IUCN Red List. Distribution areas of L. carniolicum are Trabzon, Rize, Artvin and it is also endemic to North East Anatolia. These species have high potential for use as ornamental plants with their colorful big flowers. In addition, the bulbs of these species are also used in the cosmetic industry and medicine. These are the main properties that increase the importance of L. ciliatum and L. carniolicum species. Therefore it is very important to protect the habitats of these species, ensure the continuity of their generations. The disappearance of these endemic species from our country means to disappear from the world. This review has been given in order to give some information about the endangered Lilium species of Turkey and conservation actions on these species in Turkey flora and take attention to the issue.

  11. Collective behaviour across animal species.

    Science.gov (United States)

    DeLellis, Pietro; Polverino, Giovanni; Ustuner, Gozde; Abaid, Nicole; Macrì, Simone; Bollt, Erik M; Porfiri, Maurizio

    2014-01-16

    We posit a new geometric perspective to define, detect, and classify inherent patterns of collective behaviour across a variety of animal species. We show that machine learning techniques, and specifically the isometric mapping algorithm, allow the identification and interpretation of different types of collective behaviour in five social animal species. These results offer a first glimpse at the transformative potential of machine learning for ethology, similar to its impact on robotics, where it enabled robots to recognize objects and navigate the environment.

  12. Thromboelastography in Selected Avian Species

    DEFF Research Database (Denmark)

    Andersen, Sophie Susanna Strindberg; Nielsen, Tenna W; Ribeiro, Ângela M

    2015-01-01

    Currently available assay methods and reagents are not optimized for evaluating avian hemostasis; therefore, assessing avian coagulopathies is challenging. Recently, thromboelastography (TEG), which measures the viscoelastic properties of blood, has been used clinically in mammalian species...... to diagnose and characterize hemostatic disorders. To evaluate TEG in healthy individuals of 6 avian species, we modified existing mammalian TEG protocols to allow analysis of citrated, avian whole-blood samples collected from scarlet ibis (Eudocimus ruber) (n = 13), American flamingos ( Phoenicopterus ruber...

  13. The nature of plant species.

    Science.gov (United States)

    Rieseberg, Loren H; Wood, Troy E; Baack, Eric J

    2006-03-23

    Many botanists doubt the existence of plant species, viewing them as arbitrary constructs of the human mind, as opposed to discrete, objective entities that represent reproductively independent lineages or 'units of evolution'. However, the discreteness of plant species and their correspondence with reproductive communities have not been tested quantitatively, allowing zoologists to argue that botanists have been overly influenced by a few 'botanical horror stories', such as dandelions, blackberries and oaks. Here we analyse phenetic and/or crossing relationships in over 400 genera of plants and animals. We show that although discrete phenotypic clusters exist in most genera (> 80%), the correspondence of taxonomic species to these clusters is poor (< 60%) and no different between plants and animals. Lack of congruence is caused by polyploidy, asexual reproduction and over-differentiation by taxonomists, but not by contemporary hybridization. Nonetheless, crossability data indicate that 70% of taxonomic species and 75% of phenotypic clusters in plants correspond to reproductively independent lineages (as measured by postmating isolation), and thus represent biologically real entities. Contrary to conventional wisdom, plant species are more likely than animal species to represent reproductively independent lineages.

  14. The Colletotrichum gloeosporioides species complex.

    Science.gov (United States)

    Weir, B S; Johnston, P R; Damm, U

    2012-09-15

    The limit of the Colletotrichum gloeosporioides species complex is defined genetically, based on a strongly supported clade within the Colletotrichum ITS gene tree. All taxa accepted within this clade are morphologically more or less typical of the broadly defined C. gloeosporioides, as it has been applied in the literature for the past 50 years. We accept 22 species plus one subspecies within the C. gloeosporioides complex. These include C. asianum, C. cordylinicola, C. fructicola, C. gloeosporioides, C. horii, C. kahawae subsp. kahawae, C. musae, C. nupharicola, C. psidii, C. siamense, C. theobromicola, C. tropicale, and C. xanthorrhoeae, along with the taxa described here as new, C. aenigma, C. aeschynomenes, C. alatae, C. alienum, C. aotearoa, C. clidemiae, C. kahawae subsp. ciggaro, C. salsolae, and C. ti, plus the nom. nov. C. queenslandicum (for C. gloeosporioides var. minus). All of the taxa are defined genetically on the basis of multi-gene phylogenies. Brief morphological descriptions are provided for species where no modern description is available. Many of the species are unable to be reliably distinguished using ITS, the official barcoding gene for fungi. Particularly problematic are a set of species genetically close to C. musae and another set of species genetically close to C. kahawae, referred to here as the Musae clade and the Kahawae clade, respectively. Each clade contains several species that are phylogenetically well supported in multi-gene analyses, but within the clades branch lengths are short because of the small number of phylogenetically informative characters, and in a few cases individual gene trees are incongruent. Some single genes or combinations of genes, such as glyceraldehyde-3-phosphate dehydrogenase and glutamine synthetase, can be used to reliably distinguish most taxa and will need to be developed as secondary barcodes for species level identification, which is important because many of these fungi are of biosecurity

  15. Terrestrial animals as invasive species and as species at risk from invasions

    Science.gov (United States)

    Deborah M. Finch; Dean Pearson; Joseph Wunderle; Wayne Arendt

    2010-01-01

    Including terrestrial animal species in the invasive species strategy plan is an important step in invasive species management. Invasions by nonindigenous species threaten nearly 50 percent of imperiled native species in the United States and are the Nation's second leading cause of species endangerment. Invasion and conversion of native habitats by exotic species...

  16. Malassezia Species and Pityriasis Versicolor

    Directory of Open Access Journals (Sweden)

    Gulin Rodoplu

    2016-01-01

    Full Text Available Malassezia species are found in part of the normal human cutaneous commensal flora, however it has been known for many years that the Malassezia yeasts are associated with a number of different human diseases ranging from pityriasis versicolor to seborrhoeic dermatitis. In addition, since the 1980s, they have been reported as causing opportunistic systemic infections. The taxonomy of Malassezia spp. has recently been modified to include 13 obligatorily lipophilic species, plus one non-obligatorily lipophilic species, which only rarely colonizes human hosts and currently the genus consist 14 species as M. furfur, M. pachydermatis, M. sympodialis, M. globosa, M. obtusa, M. slooffiae, M. restricta, M. dermatis, M. japonica, M. nana, M. yamatoensis, M. caprae, M. equina, M. cuniculi. Fastidious growth requirements of Malassezia yeasts defied the initial attempts to culture these organisms and their true identification and the relationship between different species only became apparent with the application of modern molecular techniques. The causative fungus is seen especially in such seborrheic areas as the scalp, face, trunk and upper back. Under the influence of various exogenous or endogenous predisposing factors, these yeasts change from the blastospore form to the mycelial form and become pathogenic. Diagnosis of pityriasis versicolor which is caused by Malassezia species is generally easy and lies on the basis of its clinical appearance and can be confirmed by mycological examination. The diagnosisis is mainly based on direct examination with potassium hydroxide (KOH and demonstration that represents pseudohyphae and blastoconidia as the typical %u201Cspaghetti and meatballs%u201D pattern. Characteristic features of the genus Malassezia include a distinctive morphology and an affinity for lipids in culture. Culture is necessary to recover the infecting strain, especially for epidemiologic purposes and also to test its antifungal susceptibility

  17. Phenotypic covariance at species' borders.

    Science.gov (United States)

    Caley, M Julian; Cripps, Edward; Game, Edward T

    2013-05-28

    Understanding the evolution of species limits is important in ecology, evolution, and conservation biology. Despite its likely importance in the evolution of these limits, little is known about phenotypic covariance in geographically marginal populations, and the degree to which it constrains, or facilitates, responses to selection. We investigated phenotypic covariance in morphological traits at species' borders by comparing phenotypic covariance matrices (P), including the degree of shared structure, the distribution of strengths of pair-wise correlations between traits, the degree of morphological integration of traits, and the ranks of matricies, between central and marginal populations of three species-pairs of coral reef fishes. Greater structural differences in P were observed between populations close to range margins and conspecific populations toward range centres, than between pairs of conspecific populations that were both more centrally located within their ranges. Approximately 80% of all pair-wise trait correlations within populations were greater in the north, but these differences were unrelated to the position of the sampled population with respect to the geographic range of the species. Neither the degree of morphological integration, nor ranks of P, indicated greater evolutionary constraint at range edges. Characteristics of P observed here provide no support for constraint contributing to the formation of these species' borders, but may instead reflect structural change in P caused by selection or drift, and their potential to evolve in the future.

  18. Aspergillus fumigatus and Related Species

    Science.gov (United States)

    Sugui, Janyce A.; Kwon-Chung, Kyung J.; Juvvadi, Praveen R.; Latgé, Jean-Paul; Steinbach, William J.

    2015-01-01

    The genus Aspergillus contains etiologic agents of aspergillosis. The clinical manifestations of the disease range from allergic reaction to invasive pulmonary infection. Among the pathogenic aspergilli, Aspergillus fumigatus is most ubiquitous in the environment and is the major cause of the disease, followed by Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Aspergillus nidulans, and several species in the section Fumigati that morphologically resemble A. fumigatus. Patients that are at risk for acquiring aspergillosis are those with an altered immune system. Early diagnosis, species identification, and adequate antifungal therapy are key elements for treatment of the disease, especially in cases of pulmonary invasive aspergillosis that often advance very rapidly. Incorporating knowledge of the basic biology of Aspergillus species to that of the diseases that they cause is fundamental for further progress in the field. PMID:25377144

  19. What is a Species? An Endless Debate

    Indian Academy of Sciences (India)

    Srimath

    a research scholar in ... perspectives are collectively termed as Phylogenetic Species ... tors view the origin of the species they study”. ..... explosion of molecular data has been the major driving force in unearthing cryptic species, it is no ...

  20. Vegetation composition and structure influences bird species ...

    African Journals Online (AJOL)

    Vegetation composition and structure influences bird species community ... variables on bird species diversity and richness of respective foraging guilds, and ... of the species assessed: (1) increasing closed cover due to woody plant density, ...

  1. Alien species recorded in the United Arab Emirates: an initial list of terrestrial and freshwater species

    Directory of Open Access Journals (Sweden)

    Pritpal Soorae

    2015-10-01

    Full Text Available Little is documented on the alien terrestrial and freshwater species in the United Arab Emirates. To address this, an assessment of terrestrial and freshwater alien species was conducted using various techniques such as a questionnaire, fieldwork data, networking with relevant people, and a detailed literature review. The results of the initial assessment show that there are 146 alien species recorded in the following seven major taxonomic groups: invertebrates 49 species, freshwater fish five species, amphibian one species, reptiles six species, birds 71 species, mammals six species and plants eight species. To inform decision makers a full list of the 146 species identified in this assessment is presented. 

  2. Man...An Endangered Species?

    Science.gov (United States)

    Department of the Interior, Washington, DC.

    The general theme of this 1968 yearbook is that man is a threatened species, facing overpopulation and unbridled technology - both self induced. The presentation is broad, relating to many aspects of conservation and natural resources in the United States in a descriptive, non-technical style. The yearbook is divided into major topics: Land…

  3. Phylogenetic relationships among Maloideae species

    Science.gov (United States)

    The Maloideae is a highly diverse sub-family of the Rosaceae containing several agronomically important species (Malus sp. and Pyrus sp.) and their wild relatives. Previous phylogenetic work within the group has revealed extensive intergeneric hybridization and polyploidization. In order to develop...

  4. Botrytis species on bulb crops

    NARCIS (Netherlands)

    Lorbeer, J.W.; Seyb, A.M.; Boer, de M.; Ende, van den J.E.

    2007-01-01

    Abstract. A number of Botrytis species are pathogens of bulb crops. Botrytis squamosa (teleomorph=Botrytotinia squamosa) causal agent of botrytis leaf blight and B. allii the causal agent of botrytis neck rotare two of the most important fungal diseases of onion. The taxonomics of several of the

  5. Endangered Species: An Educator's Handbook.

    Science.gov (United States)

    Smith, Jean, M., Comp.

    Presented are two articles, an annotated bibliography, and other information useful in teaching about endangered species, especially those found in Florida. The articles provide an ethical rationale, teaching suggestions, and a discussion of the value of wildlife. Descriptions of over 100 pertinent books, periodicals, movies, and filmstrips are in…

  6. Molecular Epidemiology of Fonsecaea Species

    NARCIS (Netherlands)

    Najafzadeh, M.J.; Sun, J.; Vicente, V.A.; Klaassen, C.H.W.; Bonifaz, A.; Gerrits van den Ende, A.H.G.; Menken, S.B.J.; de Hoog, G.S.

    2011-01-01

    To assess population diversities among 81 strains of fungi in the genus Fonsecaea that had been identified down to species level, we applied amplified fragment-length polymorphism (AFLP) technology and sequenced the internal transcribed spacer regions and the partial cell division cycle, β-tubulin,

  7. SARS – virus jumps species

    Indian Academy of Sciences (India)

    SARS – virus jumps species. Coronavirus reshuffles genes; Rotteir et al, Rotterdam showed the virus to jump from cats to mouse cells after single gene mutation ? Human disease due to virus jumping from wild or domestic animals; Present favourite animal - the cat; - edible or domestic.

  8. Species recovery in the United States: Increasing the effectiveness of the Endangered Species Act

    Science.gov (United States)

    Daniel M. Evans; Judy P. Che-Castaldo; Deborah Crouse; Frank W. Davis; Rebecca Epanchin-Niell; Curtis H. Flather; R. Kipp Frohlich; Dale D. Goble; Ya-Wei Li; Timothy D. Male; Lawrence L. Master; Matthew P. Moskwik; Maile C. Neel; Barry R. Noon; Camille Parmesan; Mark W. Schwartz; J. Michael Scott; Byron K. Williams

    2016-01-01

    The Endangered Species Act (ESA) has succeeded in shielding hundreds of species from extinction and improving species recovery over time. However, recovery for most species officially protected by the ESA - i.e., listed species - has been harder to achieve than initially envisioned. Threats to species are persistent and pervasive, funding has been insufficient...

  9. Optimal conservation of migratory species.

    Directory of Open Access Journals (Sweden)

    Tara G Martin

    Full Text Available BACKGROUND: Migratory animals comprise a significant portion of biodiversity worldwide with annual investment for their conservation exceeding several billion dollars. Designing effective conservation plans presents enormous challenges. Migratory species are influenced by multiple events across land and sea-regions that are often separated by thousands of kilometres and span international borders. To date, conservation strategies for migratory species fail to take into account how migratory animals are spatially connected between different periods of the annual cycle (i.e. migratory connectivity bringing into question the utility and efficiency of current conservation efforts. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report the first framework for determining an optimal conservation strategy for a migratory species. Employing a decision theoretic approach using dynamic optimization, we address the problem of how to allocate resources for habitat conservation for a Neotropical-Nearctic migratory bird, the American redstart Setophaga ruticilla, whose winter habitat is under threat. Our first conservation strategy used the acquisition of winter habitat based on land cost, relative bird density, and the rate of habitat loss to maximize the abundance of birds on the wintering grounds. Our second strategy maximized bird abundance across the entire range of the species by adding the constraint of maintaining a minimum percentage of birds within each breeding region in North America using information on migratory connectivity as estimated from stable-hydrogen isotopes in feathers. We show that failure to take into account migratory connectivity may doom some regional populations to extinction, whereas including information on migratory connectivity results in the protection of the species across its entire range. CONCLUSIONS/SIGNIFICANCE: We demonstrate that conservation strategies for migratory animals depend critically upon two factors: knowledge of

  10. The effects of melatonin on bovine uniparental embryos development in vitro and the hormone secretion of COCs

    Directory of Open Access Journals (Sweden)

    Shujuan Wang

    2017-07-01

    Full Text Available Melatonin is a unique multifunctional molecule that mediates reproductive functions in animals. In this study, we investigated the effects of melatonin on bovine parthenogenetic and androgenetic embryonic development, oocyte maturation, the reactive oxygen species (ROS levels in parthenogenetic and androgenetic embryos and cumulus—oocyte complexes (COCs hormone secretion with melatonin supplementation at four concentrations (0, 10, 20, and 30 pmol/mL, respectively. The results showed that melatonin significantly promoted the rates of bovine parthenogenetic and androgenetic embryonic cleavage and morula and blastocysts development (P < 0.05. The rate of cleavage was higher in the androgenetic embryo than that in the parthenogenetic embryo. Compared with the parthenogenetic embryos, the androgenetic embryos had a poor developmental competence from morula to blastocyst stage. Moreover, the levels of ROS were significantly lower in the parthenogenetic and androgenetic embryoes with melatonin-treated group than that of the control group (P < 0.05. Melatonin supplemented significantly increased the maturation rate of oocyte in vitro (P < 0.05. More importantly, melatonin significantly promoted the secretion of progesterone and estradiol by COCs (P < 0.05. To reveal the regulatory mechanism of melatonin on steroids synthesis, we found that steroidogenic genes (CYP11A1, CYP19A1 and StAR were upregulated, suggesting that melatonin regulated estradiol and progesterone secretion through mediating the expression of steroidogenic genes (CYP11A1, CYP19A1 and StAR. In addition, MT1 and MT2 were identified in bovine early parthenogenetic and androgenetic embryos using western blot. It could be concluded that melatonin had beneficial effects on bovine oocyte in vitro maturation, COC hormone secretion, early development of subsequent parthenogenetic and androgenetic embryos. It is inferred that melatonin could be used to enhance the efficiency of in

  11. Synopsis of the Oxyethira flavicornis species group with new Japanese Oxyethira species (Trichoptera, Hydroptilidae

    Directory of Open Access Journals (Sweden)

    Oláh, J.

    2013-06-01

    Full Text Available A brief synopsis of the Oxyethira flavicornis species group is produced by the examination of type materials. Diagrammatic drawings with similar style were prepared for all the known and for the new species. Short description of genus Oxyethira, subgenus Oxyethira, species group of Oxyethira flavicornis are presented together with the description of five species clusters: O. datra new species cluster, O. ecornuta new species cluster, O. flavicornis new species cluster, O. hiroshima new species cluster, O. tiunovae new species cluster. Five new species are described from the O. flavicornis species group: O chitosea sp. n., O. hena sp. n., O. hiroshima sp. n., O. kakida sp. n., O. mekunna sp. n. One new species is described from the Oxyethira grisea species group: Oxyethira ozea sp. n. and two new species from the Oxyethira ramosa species group: Oxyethira miea sp. n., Oxyethira okinawa sp. n.

  12. Floral reward in Ranunculaceae species

    Directory of Open Access Journals (Sweden)

    Bożena Denisow

    2016-04-01

    Full Text Available Floral reward is important in ecological and evolutionary perspectives and essential in pollination biology. For example, floral traits, nectar and pollen features are essential for understanding the functional ecology, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. We believe to present a synthetic description in the field of floral reward in Ranunculaceae family important in pollination biology and indicating connections between ecological and evolutionary approaches. The links between insect visitors’ behaviour and floral reward type and characteristics exist. Ranunculaceae is a family of aboot 1700 species (aboot 60 genera, distributed worldwide, however the most abundant representatives are in temperate and cool regions of the northern and southern hemispheres. The flowers are usually radially symmetric (zygomorphic and bisexual, but in Aconitum, Aquilegia are bilaterally symmetric (zygomorphic. Most Ranunculaceae flowers offer no nectar, only pollen (e.g., Ranunculus, Adonis vernalis, Thalictrum, but numerous species create trophic niches for different wild pollinators (e.g. Osmia, Megachile, Bombus, Andrena (Denisow et al. 2008. Pollen is a source of protein, vitamins, mineral salts, organic acids and hormones, but the nutritional value varies greatly between different plant species. The pollen production can differ significantly between Ranunculacea species. The mass of pollen produced in anthers differ due to variations in the number of developed anthers. For example, interspecies differences are considerable, 49 anthers are noted in Aquilegia vulgaris, 70 anthers in Ranunculus lanuginosus, 120 in Adonis vernalis. A significant intra-species differences’ in the number of anthers are also noted (e.g. 41 to 61 in Aquilegia vulgaris, 23-45 in Ranunculus cassubicus. Pollen production can be up to 62 kg per ha for Ranunculus acer

  13. ICRAF Species Switchboard. Version 1.2

    DEFF Research Database (Denmark)

    Kindt, R.; Ordonez, J.; Smith, E.

    2015-01-01

    The current version of the Agroforestry Species Switchboard documents the presence of a total of 26,135 plant species (33,813 species including synonyms) across 19 web-based databases. When available, hyperlinks to information on the selected species in particular databases are provided. In total...

  14. Parthenogenesis through the ice ages: A biogeographic analysis of Caucasian rock lizards (genus Darevskia).

    Science.gov (United States)

    Freitas, Susana; Rocha, Sara; Campos, João; Ahmadzadeh, Faraham; Corti, Claudia; Sillero, Neftali; Ilgaz, Çetin; Kumlutaş, Yusuf; Arakelyan, Marine; Harris, D James; Carretero, Miguel A

    2016-09-01

    Darevskia rock lizards include both sexual and parthenogenetic species, mostly distributed in the heterogeneous and ecologically diverse Caucasus. The parthenogenetic species originated via directional hybridogenesis, with only some of the sexual species known to serve as parentals. However, it remains unclear when and where these events happened and how many parental lineages were involved. A multilocus phylogeographic analysis was performed on the parthenogens D. unisexualis, D. bendimahiensis and D. uzzeli, and their putative maternal species D. raddei. Results show the parthenogenetic species all have relatively recent origins, approximately 200-70kyr ago, and at least three hybridization events were involved in their formation. Ecological niche models identify the region where hybridization events leading to the formation of D. unisexualis took place, namely in the northeast of the current distribution. Models also suggest that the sexual D. raddei might have undergone a habitat shift between the Last Interglacial and the Last Glacial Maximum. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Ranking species in mutualistic networks

    Science.gov (United States)

    Domínguez-García, Virginia; Muñoz, Miguel A.

    2015-02-01

    Understanding the architectural subtleties of ecological networks, believed to confer them enhanced stability and robustness, is a subject of outmost relevance. Mutualistic interactions have been profusely studied and their corresponding bipartite networks, such as plant-pollinator networks, have been reported to exhibit a characteristic ``nested'' structure. Assessing the importance of any given species in mutualistic networks is a key task when evaluating extinction risks and possible cascade effects. Inspired in a recently introduced algorithm -similar in spirit to Google's PageRank but with a built-in non-linearity- here we propose a method which -by exploiting their nested architecture- allows us to derive a sound ranking of species importance in mutualistic networks. This method clearly outperforms other existing ranking schemes and can become very useful for ecosystem management and biodiversity preservation, where decisions on what aspects of ecosystems to explicitly protect need to be made.

  16. Competitive intransitivity promotes species coexistence.

    Science.gov (United States)

    Laird, Robert A; Schamp, Brandon S

    2006-08-01

    Using a spatially explicit cellular automaton model with local competition, we investigate the potential for varied levels of competitive intransitivity (i.e., nonhierarchical competition) to promote species coexistence. As predicted, on average, increased levels of intransitivity result in more sustained coexistence within simulated communities, although the outcome of competition also becomes increasingly unpredictable. Interestingly, even a moderate degree of intransitivity within a community can promote coexistence, in terms of both the length of time until the first competitive exclusion and the number of species remaining in the community after 500 simulated generations. These results suggest that modest levels of intransitivity in nature, such as those that are thought to be characteristic of plant communities, can contribute to coexistence and, therefore, community-scale biodiversity. We explore a potential connection between competitive intransitivity and neutral theory, whereby competitive intransitivity may represent an important mechanism for "ecological equivalence."

  17. Charcoal anatomy of forest species

    Directory of Open Access Journals (Sweden)

    Graciela Inés Bolzon de Muñiz1

    2012-09-01

    Full Text Available Vegetal charcoal retains the anatomical structure of the wood and may permit its botanical identification, which depends on species characteristics, the charcoal fragments size and preservation state. Anatomical characterization of ten forest species charcoal was done envisaging the identification and control of illegal charcoal. Differences between gymnosperms and angiosperms are evident in carbonized wood. Vessel diameter was statistically different between wood and charcoal in Vatairea guianensis, Mezilaurus itauba, Calophyllum brasiliense e Qualea cf. acuminata, and vessel frequency in Vatairea guianensis, Manilkara huberi, Qualea cf. acuminata e Simarouba amara. The anatomical structure from wood, in general aspects, is constant during carbonization process using temperature of 450°C, being possible to identify the material by using its cellular components.

  18. Population Genomics of Paramecium Species.

    Science.gov (United States)

    Johri, Parul; Krenek, Sascha; Marinov, Georgi K; Doak, Thomas G; Berendonk, Thomas U; Lynch, Michael

    2017-05-01

    Population-genomic analyses are essential to understanding factors shaping genomic variation and lineage-specific sequence constraints. The dearth of such analyses for unicellular eukaryotes prompted us to assess genomic variation in Paramecium, one of the most well-studied ciliate genera. The Paramecium aurelia complex consists of ∼15 morphologically indistinguishable species that diverged subsequent to two rounds of whole-genome duplications (WGDs, as long as 320 MYA) and possess extremely streamlined genomes. We examine patterns of both nuclear and mitochondrial polymorphism, by sequencing whole genomes of 10-13 worldwide isolates of each of three species belonging to the P. aurelia complex: P. tetraurelia, P. biaurelia, P. sexaurelia, as well as two outgroup species that do not share the WGDs: P. caudatum and P. multimicronucleatum. An apparent absence of global geographic population structure suggests continuous or recent dispersal of Paramecium over long distances. Intergenic regions are highly constrained relative to coding sequences, especially in P. caudatum and P. multimicronucleatum that have shorter intergenic distances. Sequence diversity and divergence are reduced up to ∼100-150 bp both upstream and downstream of genes, suggesting strong constraints imposed by the presence of densely packed regulatory modules. In addition, comparison of sequence variation at non-synonymous and synonymous sites suggests similar recent selective pressures on paralogs within and orthologs across the deeply diverging species. This study presents the first genome-wide population-genomic analysis in ciliates and provides a valuable resource for future studies in evolutionary and functional genetics in Paramecium. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Haemolytic glycoglycerolipids from Gymnodinium species.

    Science.gov (United States)

    Parrish, C C; Bodennec, G; Gentien, P

    1998-03-01

    Glycoglycerolipids derived from microalgae can be a source of biologically active substances including toxins. Such glycolipids were analysed in two isolates of toxic marine dinoflagellates from European waters. The lipids of Gymnodinium mikimotoi contained 17% of monogalactosyl diacylglycerol (MGDG) and digalactosyl diacylglycerol (DGDG), while in Gymnodinium sp. the proportion was 35%. MGDG and DGDG from both species were haemolytic. The major unsaturated fatty acid in both algal glycolipids was 18:5 omega 3.

  20. Chemokines in teleost fish species.

    Science.gov (United States)

    Alejo, Alí; Tafalla, Carolina

    2011-12-01

    Chemokines are chemoattractant cytokines defined by the presence of four conserved cysteine residues which in mammals can be divided into four subfamilies depending on the arrangement of the first two conserved cysteines in their sequence: CXC (α), CC (β), C and CX(3)C classes. Evolutionarily, fish can be considered as an intermediate step between species which possess only innate immunity (invertebrates) and species with a fully developed acquired immune network such as mammals. Therefore, the functionality of their different immune cell types and molecules is sometimes also intermediate between innate and acquired responses. The first chemokine gene identified in a teleost was a rainbow trout (Oncorhynchus mykiss) chemokine designated as CK1 in 1998. Since then, many different chemokine genes have been identified in several fish species, but their role in homeostasis and immune response remains largely unknown. Extensive genomic duplication events and the fact that chemokines evolve more quickly than other immune genes, make it very difficult to establish true orthologues between fish and mammalian chemokines that would help us with the ascription of immune roles. In this review, we describe the current state of knowledge of chemokine biology in teleost fish, focusing mainly on which genes have been identified so far and highlighting the most important aspects of their expression regulation, due to the great lack of functional information available for them. As the number of chemokine genes begins to close down for some teleost species, there is an important need for functional assays that may elucidate the role of each of these molecules within the fish immune response. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Candida Species Biofilms’ Antifungal Resistance

    Science.gov (United States)

    Silva, Sónia; Rodrigues, Célia F.; Araújo, Daniela; Rodrigues, Maria Elisa; Henriques, Mariana

    2017-01-01

    Candida infections (candidiasis) are the most prevalent opportunistic fungal infection on humans and, as such, a major public health problem. In recent decades, candidiasis has been associated to Candida species other than Candida albicans. Moreover, biofilms have been considered the most prevalent growth form of Candida cells and a strong causative agent of the intensification of antifungal resistance. As yet, no specific resistance factor has been identified as the sole responsible for the increased recalcitrance to antifungal agents exhibited by biofilms. Instead, biofilm antifungal resistance is a complex multifactorial phenomenon, which still remains to be fully elucidated and understood. The different mechanisms, which may be responsible for the intrinsic resistance of Candida species biofilms, include the high density of cells within the biofilm, the growth and nutrient limitation, the effects of the biofilm matrix, the presence of persister cells, the antifungal resistance gene expression and the increase of sterols on the membrane of biofilm cells. Thus, this review intends to provide information on the recent advances about Candida species biofilm antifungal resistance and its implication on intensification of the candidiasis. PMID:29371527

  2. Linking Keystone Species and Functional Groups: A New Operational Definition of the Keystone Species Concept

    OpenAIRE

    Robert D. Davic

    2003-01-01

    The concept of the "keystone species" is redefined to allow for the a priori prediction of these species within ecosystems. A keystone species is held to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This operational definition links the community importance of keystone species to a specific ecosystem process, e.g., the regulation of species diversity, within functional groups ...

  3. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia

    2018-05-23

    Understanding what determines species\\' geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. \\'community structure\\') reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species\\' large-scale distributions, and this information can improve the predictions of species distributions.

  4. Alien species in the Finnish weed flora

    Directory of Open Access Journals (Sweden)

    T. HYVÖNEN

    2008-12-01

    Full Text Available The present study aimed at assessing the invasion of alien weed species in Finland based on a review of their occurrence in the Finnish weed flora. The evaluation was conducted for the three phases of the invasion process, i.e. introduction, naturalization and invasion. The literature review revealed that 815 alien weed species occur in Finland of which 314 are regarded as naturalized. Based on their occurrence in different climate zones, the risk of naturalization of new harmful alien weed species was deemed low for those species not currently found in Finland, but higher for species occurring as casual aliens in Finland. In the latter group, 10 species of concern were detected. Exploration of the distribution patterns of naturalized species within Finland revealed species occupancy to be dependent on the residence time of the species. Established neophytes can be expected to extend their ranges and to increase occupation of agricultural habitats in the future.;

  5. Natural Constraints to Species Diversification.

    Directory of Open Access Journals (Sweden)

    Eric Lewitus

    2016-08-01

    Full Text Available Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the

  6. Natural Constraints to Species Diversification.

    Science.gov (United States)

    Lewitus, Eric; Morlon, Hélène

    2016-08-01

    Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades) within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the deep-time evolution of

  7. Natural Constraints to Species Diversification

    Science.gov (United States)

    Lewitus, Eric; Morlon, Hélène

    2016-01-01

    Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades) within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the deep-time evolution of

  8. The Invasive Species Forecasting System

    Science.gov (United States)

    Schnase, John; Most, Neal; Gill, Roger; Ma, Peter

    2011-01-01

    The Invasive Species Forecasting System (ISFS) provides computational support for the generic work processes found in many regional-scale ecosystem modeling applications. Decision support tools built using ISFS allow a user to load point occurrence field sample data for a plant species of interest and quickly generate habitat suitability maps for geographic regions of management concern, such as a national park, monument, forest, or refuge. This type of decision product helps resource managers plan invasive species protection, monitoring, and control strategies for the lands they manage. Until now, scientists and resource managers have lacked the data-assembly and computing capabilities to produce these maps quickly and cost efficiently. ISFS focuses on regional-scale habitat suitability modeling for invasive terrestrial plants. ISFS s component architecture emphasizes simplicity and adaptability. Its core services can be easily adapted to produce model-based decision support tools tailored to particular parks, monuments, forests, refuges, and related management units. ISFS can be used to build standalone run-time tools that require no connection to the Internet, as well as fully Internet-based decision support applications. ISFS provides the core data structures, operating system interfaces, network interfaces, and inter-component constraints comprising the canonical workflow for habitat suitability modeling. The predictors, analysis methods, and geographic extents involved in any particular model run are elements of the user space and arbitrarily configurable by the user. ISFS provides small, lightweight, readily hardened core components of general utility. These components can be adapted to unanticipated uses, are tailorable, and require at most a loosely coupled, nonproprietary connection to the Web. Users can invoke capabilities from a command line; programmers can integrate ISFS's core components into more complex systems and services. Taken together, these

  9. Why some plant species are rare.

    Science.gov (United States)

    Wieger Wamelink, G W; Wamelink, G W Weiger; Goedhart, Paul W; Frissel, Joep; Frissel, Josep Y

    2014-01-01

    Biodiversity, including plant species diversity, is threatened worldwide as a result of anthropogenic pressures such as an increase of pollutants and climate change. Rare species in particular are on the verge of becoming extinct. It is still unclear as to why some plant species are rare and others are not. Are they rare due to: intrinsic reasons, dispersal capacity, the effects of management or abiotic circumstances? Habitat preference of rare plant species may play an important role in determining why some species are rare. Based on an extensive data set of soil parameters we investigated if rarity is due to a narrow habitat preference for abiotic soil parameters. For 23 different abiotic soil parameters, of which the most influential were groundwater-table, soil-pH and nutrient-contents, we estimated species responses for common and rare species. Based on the responses per species we calculated the range of occurrence, the range between the 5 and 95 percentile of the response curve giving the habitat preference. Subsequently, we calculated the average response range for common and rare species. In addition, we designed a new graphic in order to provide a better means for presentation of the results. The habitat preferences of rare species for abiotic soil conditions are significantly narrower than for common species. Twenty of the twenty-three abiotic parameters showed on average significantly narrower habitat preferences for rare species than for common species; none of the abiotic parameters showed on average a narrower habitat preference for common species. The results have major implications for the conservation of rare plant species; accordingly management and nature development should be focussed on the maintenance and creation of a broad range of environmental conditions, so that the requirements of rare species are met. The conservation of (abiotic) gradients within ecosystems is particularly important for preserving rare species.

  10. Rabbit embryonic stem cell lines derived from fertilized, parthenogenetic or somatic cell nuclear transfer embryos

    International Nuclear Information System (INIS)

    Fang, Zhen F.; Gai, Hui; Huang, You Z.; Li, Shan G.; Chen, Xue J.; Shi, Jian J.; Wu, Li; Liu, Ailian; Xu, Ping; Sheng, Hui Z.

    2006-01-01

    Embryonic stem cells were isolated from rabbit blastocysts derived from fertilization (conventional rbES cells), parthenogenesis (pES cells) and nuclear transfer (ntES cells), and propagated in a serum-free culture system. Rabbit ES (rbES) cells proliferated for a prolonged time in an undifferentiated state and maintained a normal karyotype. These cells grew in a monolayer with a high nuclear/cytoplasm ratio and contained a high level of alkaline phosphate activity. In addition, rbES cells expressed the pluripotent marker Oct-4, as well as EBAF2, FGF4, TDGF1, but not antigens recognized by antibodies against SSEA-1, SSEA-3, SSEA-4, TRA-1-10 and TRA-1-81. All 3 types of ES cells formed embryoid bodies and generated teratoma that contained tissue types of all three germ layers. rbES cells exhibited a high cloning efficiency, were genetically modified readily and were used as nuclear donors to generate a viable rabbit through somatic cell nuclear transfer. In combination with genetic engineering, the ES cell technology should facilitate the creation of new rabbit lines

  11. Construction and long term preservation of clonal transgenic silkworms using a parthenogenetic strain

    Czech Academy of Sciences Publication Activity Database

    Zabelina, Valeriya; Uchino, K.; Mochida, Y.; Yonemura, N.; Klymenko, V.; Sezutsu, H.; Tamura, T.; Sehnal, František

    2015-01-01

    Roč. 81, Oct 01 (2015), s. 28-35 ISSN 0022-1910 R&D Projects: GA MŠk(CZ) EE2.3.30.0032; GA ČR GAP502/10/2382 Institutional support: RVO:60077344 Keywords : silkworm * transgenesis * parthenogenesis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.267, year: 2015 http://www.sciencedirect.com/science/article/pii/S0022191015001304

  12. Sexual versus Asexual Reproduction: Distinct Outcomes in Relative Abundance of Parthenogenetic Mealybugs following Recent Colonization.

    Science.gov (United States)

    Tabata, Jun; Ichiki, Ryoko T; Tanaka, Hirotaka; Kageyama, Daisuke

    2016-01-01

    Asexual reproduction, including parthenogenesis in which embryos develop within a female without fertilization, is assumed to confer advantages over sexual reproduction, which includes a "cost of males." Sexual reproduction largely predominates in animals, however, indicating that this cost is outweighed by the genetic and/or ecological benefits of sexuality, including the acquisition of advantageous mutations occurring in different individuals and the elimination of deleterious mutations. But the evolution of sexual reproduction remains unclear, because we have limited examples that demonstrate the relative success of sexual lineages in the face of competition from asexual lineages in the same environment. Here we investigated a sympatric occurrence of sexual and asexual reproduction in the pineapple mealybug, Dysmicoccus brevipes. This pest invaded southwestern Japan, including Okinawa and Ishigaki Islands, in the 1930s in association with imported pineapple plants. Our recent censuses demonstrated that on Okinawa sexually reproducing individuals can coexist with and even dominate asexual individuals in the presence of habitat and resource competition, which is considered to be severe for this nearly immobile insect. Molecular phylogeny based on partial DNA sequences in the mitochondrial and nuclear genomes, as well as the endosymbiotic bacterial genome, revealed that the asexual lineage diverged from a common sexual ancestor in the relatively recent past. In contrast, only the asexual lineage exhibiting obligate apomictic thelytoky was discovered on Ishigaki. Co-existence of the two lineages cannot be explained by the results of laboratory experiments, which showed that the intrinsic rate of increase in the sexual lineage was not obviously superior to that of the asexual lineage. Differences in biotic and/or abiotic selective forces operating on the two islands might be the cause of this discrepancy. This biological system offers a unique opportunity to assess the relative success of sexual versus asexual lineages with an unusual morphology and life cycle.

  13. Evaluation of different feeds for optimal growth and survival of parthenogenetic brine shrimp, Artemia

    Digital Repository Service at National Institute of Oceanography (India)

    Sumitra-Vijayaraghavan; Krishnakumari, L.; Royan, J.P.

    intestinalis and Ulva fasciata). Rice bran yielded best growth at an optimal level of 0.1 and 0.5 mg.ml-1 d-1 respectively for 1-4 and 4-8 d old larvae. Rice bran was also the best food for outdoor cultures. Artemia fed rice bran took shortest time to reach...

  14. Development and quality of porcine parthenogenetically activated embryos after removal of zona pellucida

    DEFF Research Database (Denmark)

    Li, Rong; Liu, Ying; Pedersen, Hanne Skovsgaard

    2013-01-01

    at all developmental stages, but the difference was only significant at the five-cell stage. When compared with development of zona-intact embryos, ZP removal decreased the overall blastocyst percentage (83.9 ± 2.0 vs. 72.5 ± 2.9, respectively) and especially the percentage of good morphology (grades 1......, the developmental percentages, the frequency of apoptosis, and robustness after removal of the ZP by pronase. Three experiments were made between zona-free PA embryos and zona-intact embryos: (1) determination of the timing of developmental stages using time-lapse observations for 6 days; (2) determination...

  15. Effects of high hydrostatic pressure on genomic expression profiling of porcine parthenogenetic activated and cloned embryos

    DEFF Research Database (Denmark)

    Lin, Lin; Luo, Yonglun; Sørensen, Peter

    2014-01-01

    derived by PA or HMC. Hierarchical clustering depicted stage-specific genomic expression profiling. At the 4-cell and blastocyst stages, 103 and 163 transcripts were differentially expressed between the HMC and PA embryos, respectively (P

  16. Secondary queens in the parthenogenetic termite Cavitermes tuberosus develop through a transitional helper stage

    Czech Academy of Sciences Publication Activity Database

    Hellemans, S.; Fournier, D.; Hanus, Robert; Roisin, Y.

    2017-01-01

    Roč. 19, č. 6 (2017), s. 253-262 ISSN 1520-541X Institutional support: RVO:61388963 Keywords : facultative parthenogenesis * replacement queens * termites * asexual queen succession * ontogeny * Cavitermes Subject RIV: EG - Zoology OBOR OECD: Developmental biology Impact factor: 2.243, year: 2016

  17. SIS - Species and Stock Administrative Data Set

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Species and Stock Administrative data set within the Species Information System (SIS) defines entities within the database that serve as the basis for recording...

  18. Assessing Pesticides under the Endangered Species Act

    Science.gov (United States)

    EPA’s pesticide risk assessment and regulatory processes ensure that protections are in place for all populations of non-target species. We have developed risk assessment procedures to determine potential for harm to individuals of a listed species.

  19. Molecular Diagnosis of Pathogenic Sporothrix Species

    NARCIS (Netherlands)

    Rodrigues, Anderson Messias; de Hoog, G Sybren; de Camargo, Zoilo Pires

    2015-01-01

    BACKGROUND: Sporotrichosis is a chronic (sub)cutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species

  20. 76 FR 68776 - Invasive Species Advisory Committee

    Science.gov (United States)

    2011-11-07

    ... broad array of issues related to preventing the introduction of invasive species and providing for their...-2012 Invasive Species National Management Plan. The meeting is open to the public. An orientation...

  1. Species coextinctions and the biodiversity crisis.

    Science.gov (United States)

    Koh, Lian Pin; Dunn, Robert R; Sodhi, Navjot S; Colwell, Robert K; Proctor, Heather C; Smith, Vincent S

    2004-09-10

    To assess the coextinction of species (the loss of a species upon the loss of another), we present a probabilistic model, scaled with empirical data. The model examines the relationship between coextinction levels (proportion of species extinct) of affiliates and their hosts across a wide range of coevolved interspecific systems: pollinating Ficus wasps and Ficus, parasites and their hosts, butterflies and their larval host plants, and ant butterflies and their host ants. Applying a nomographic method based on mean host specificity (number of host species per affiliate species), we estimate that 6300 affiliate species are "coendangered" with host species currently listed as endangered. Current extinction estimates need to be recalibrated by taking species coextinctions into account.

  2. 77 FR 23740 - Invasive Species Advisory Committee

    Science.gov (United States)

    2012-04-20

    ... broad array of issues related to preventing the introduction of invasive species and providing for their... both ecological and management contexts, will center on topics that: (1) Pertain to invasive species...

  3. Endangered species toxicity extrapolation using ICE models

    Science.gov (United States)

    The National Research Council’s (NRC) report on assessing pesticide risks to threatened and endangered species (T&E) included the recommendation of using interspecies correlation models (ICE) as an alternative to general safety factors for extrapolating across species. ...

  4. Foliar flavonoids of nine species of Bauhinia

    OpenAIRE

    SALATINO, ANTONIO; BLATT, CECÍLIA T.T.; SANTOS, DÉBORAH Y.A.C. DOS; VAZ, ANGELA M.S.F.

    1999-01-01

    Foliar flavonoids of nine species of Bauhinia were isolated and identified. All the compounds correspond to glycosides derived from kaempferol, quercetin, isorhamnetin and myricetin. Derivatives of the latter aglyconhe seem to be rare in Bauhinia. Derivatives of isorhamnetin are commonly found in species of subgenus Bauhinia and were not detected in the two species of subgenus Phanera. Flavonoid patterns of species of the former subgenus are in general more complex than those of the latter. ...

  5. New species of Cystolepiota from China

    Directory of Open Access Journals (Sweden)

    Meng-Lin Xu

    2016-10-01

    Full Text Available In this paper, a new species, Cystolepiota pseudofumosifolia, is introduced. C. pseudofumosifolia is characterized by granulose or powdery pileus with an anatomic structure that is loosely globose, as well as ellipsoid cells in chains in the pileus covering the cheilocystidia. This new species is compared to the related and similar Cystolepiota species in morphology and molecular phylogeny based on Internal transcribed spacer sequences. Both types of data support our specimens as a new species in the genus Cystolepiota.

  6. Biodiversity in the cyclic competition system of three species according to the emergence of mutant species

    Science.gov (United States)

    Park, Junpyo

    2018-05-01

    Understanding mechanisms which promote or hinder existing ecosystems are important issues in ecological sciences. In addition to fundamental interactions such as competition and migration among native species, existing ecosystems can be easily disturbed by external factors, and the emergence of new species may be an example in such cases. The new species which does not exist in a current ecosystem can be regarded as either alien species entered from outside or mutant species born by mutation in existing normal species. Recently, as existing ecosystems are getting influenced by various physical/chemical external factors, mutation due to anthropogenic and environmental factors can occur more frequently and is thus attracting much attention for the maintenance of ecosystems. In this paper, we consider emergences of mutant species among self-competing three species in the cyclic dominance. By defining mutation as the birth of mutant species, we investigate how mutant species can affect biodiversity in the existing ecosystem. Through microscopic and macroscopic approaches, we have found that the society of existing normal species can be disturbed by mutant species either the society is maintained accompanying with the coexistence of all species or jeopardized by occupying of mutant species. Due to the birth of mutant species, the existing society may be more complex by constituting two different groups of normal and mutant species, and our results can be contributed to analyze complex ecosystems of many species. We hope our findings may propose a new insight on mutation in cyclic competition systems of many species.

  7. Linking Keystone Species and Functional Groups: A New Operational Definition of the Keystone Species Concept

    Directory of Open Access Journals (Sweden)

    Robert D. Davic

    2003-07-01

    Full Text Available The concept of the "keystone species" is redefined to allow for the a priori prediction of these species within ecosystems. A keystone species is held to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This operational definition links the community importance of keystone species to a specific ecosystem process, e.g., the regulation of species diversity, within functional groups at lower trophic levels that are structured by competition for a limited resource. The a priori prediction of keystone species has applied value for the conservation of natural areas.

  8. Unimodal models to relate species to environment

    NARCIS (Netherlands)

    Braak, ter C.J.F.

    1987-01-01

    To assess the impact of environmental change on biological communities knowledge about species-environment relationships is indispensable. Ecologists attempt to uncover the relationships between species and environment from data obtained from field surveys. In the survey, species are scored on their

  9. 3 CFR - The Endangered Species Act

    Science.gov (United States)

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false The Endangered Species Act Presidential Documents Other Presidential Documents Memorandum of March 3, 2009 The Endangered Species Act Memorandum for the Heads of Executive Departments and Agencies The Endangered Species Act (ESA), 16 U.S.C. 1531 et seq...

  10. 75 FR 29359 - Invasive Species Advisory Committee

    Science.gov (United States)

    2010-05-25

    ... Council is co-chaired by the Secretary of the Interior, the Secretary of Agriculture, and the Secretary of... of the most invaded marine/coastal environments in the world, with over 50 invasive species that... development of state invasive species councils. DATES: Meeting of the Invasive Species Advisory Committee...

  11. Endangered Species & Biodiversity: A Classroom Project & Theme

    Science.gov (United States)

    Lauro, Brook

    2012-01-01

    Students discover the factors contributing to species losses worldwide by conducting a project about endangered species as a component of a larger classroom theme of biodiversity. Groups conduct research using online endangered- species databases and present results to the class using PowerPoint. Students will improve computer research abilities…

  12. The Gilbertiodendron ogoouense species complex (Leguminosae

    NARCIS (Netherlands)

    Burgt, van der X.M.; Mackinder, B.A.; Wieringa, J.J.; Estrella, de la Manuel

    2015-01-01

    The Gilbertiodendron ogoouense species complex consists of 14 tree species. Eight species are here newly described and one is here reinstated: G. bambolense Burgt; G. breteleri Burgt; G. ebo Burgt & Mackinder; G. ecoukense (Pellegr.) Burgt; G. maximum Burgt & Wieringa; G. minkebense Burgt

  13. Brachyspira Species and Gastroenteritis in Humans

    NARCIS (Netherlands)

    Westerman, L.J.; Boer, de R.F.; Roelfsema, J.H.; Friesema, I.H.M.; Kortbeek, L.M.; Wagenaar, J.A.; Bonten, M.J.M.; Kusters, J.G.

    2013-01-01

    Brachyspira species have been implicated as a potential cause of gastroenteritis in humans; this is, however, controversial. In 733 gastroenteritis cases and 464 controls, we found 29 samples positive for Brachyspira species (2.3% of cases and 2.6% of controls; P = 0.77). Brachyspira species were

  14. Brachyspira Species and Gastroenteritis in Humans

    NARCIS (Netherlands)

    Westerman, L J; de Boer, R F; Roelfsema, J H; Friesema, I H M; Kortbeek, L M; Wagenaar, J A; Bonten, M J M; Kusters, J G

    Brachyspira species have been implicated as a potential cause of gastroenteritis in humans; this is, however, controversial. In 733 gastroenteritis cases and 464 controls, we found 29 samples positive for Brachyspira species (2.3% of cases and 2.6% of controls; P = 0.77). Brachyspira species were

  15. 22 CFR 216.5 - Endangered species.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Endangered species. 216.5 Section 216.5 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ENVIRONMENTAL PROCEDURES § 216.5 Endangered species. It is A... endangered or threatened species and their critical habitats. The Initial Environmental Examination for each...

  16. Invasive Species Science Update (No. 7)

    Science.gov (United States)

    Dean Pearson; Yvette Ortega; Jack Butler

    2014-01-01

    Invasive Species Science Updates are designed to keep managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, as well as highlight breaking news related to invasive species issues. The newsletter is produced by the RMRS Invasive Species Working Group (ISWG), which is a core group of scientists who volunteer to coordinate...

  17. Do invasive plant species alter soil health?

    Science.gov (United States)

    Invasive species may alter soil characteristics or interact with the soil microbial community to yield a competitive advantage. Our objectives were to determine: if invasive plant species alter soil properties important to soil health; and the long-term effects of invasive plant species on soil pro...

  18. Options in dealing with marine alien species

    NARCIS (Netherlands)

    Pelt-Heerschap, van H.M.L.; Sneekes, A.C.; Foekema, E.M.

    2015-01-01

    Invasive species can have strong impact on the local ecosystem, not only substantial impact on the local ecosystem, but also on economy and human health. This review on marine alien species outlines aspects of prevention, eradication and control strategies. When managing invasive species, prevention

  19. Species rarity: definition, causes, and classification

    Science.gov (United States)

    Curtis H. Flather; Carolyn Hull Sieg

    2007-01-01

    In virtually all ecological communities around the world, most species are represented by few individuals, and most individuals come from only a few of the most common species. Why this distribution of species abundances is so regularly observed among different taxonomic sets in geographically diverse systems is a question that has received considerable theoretical and...

  20. New french uranium mineral species

    International Nuclear Information System (INIS)

    Branche, G.; Chervet, J.; Guillemin, C.

    1952-01-01

    In this work, the authors study the french new uranium minerals: parsonsite and renardite, hydrated phosphates of lead and uranium; kasolite: silicate hydrated of uranium and lead uranopilite: sulphate of uranium hydrated; bayleyite: carbonate of uranium and of hydrated magnesium; β uranolite: silicate of uranium and of calcium hydrated. For all these minerals, the authors give the crystallographic, optic characters, and the quantitative chemical analyses. On the other hand, the following species, very rare in the french lodgings, didn't permit to do quantitative analyses. These are: the lanthinite: hydrated uranate oxide; the α uranotile: silicate of uranium and of calcium hydrated; the bassetite: uranium phosphate and of hydrated iron; the hosphuranylite: hydrated uranium phosphate; the becquerelite: hydrated uranium oxide; the curite: oxide of uranium and lead hydrated. Finally, the authors present at the end of this survey a primary mineral: the brannerite, complex of uranium titanate. (author) [fr

  1. Satellite tracking of threatened species

    Science.gov (United States)

    Williams, M.; Lunsford, A.; Ellis, D.; Robinson, J.; Coronado, P.; Campbell, W.

    1998-01-01

    In 1990, a joint effort of two U.S. federal agencies, NASA Goddard Space Flight Center (GSFC) and the Patuxent Wildlife Research Center, began. We initially joined forces in a project that used satellite telemetry to discover the winter home of a tiny dwindling population of Siberian Cranes. Since then several projects have emerged, and a web site was created to follow some of these activities. This web site is called the Satellite Tracking of Threatened Species and its location is http://sdcd.gsfc.nasa.gov/ISTO/satellite_tracking. It describes the overall program, and links you to three subsections that describe the projects in more detail: Satellite Direct Readout, Birdtracks, and Birdworld.

  2. Ensemble forecasting of species distributions.

    Science.gov (United States)

    Araújo, Miguel B; New, Mark

    2007-01-01

    Concern over implications of climate change for biodiversity has led to the use of bioclimatic models to forecast the range shifts of species under future climate-change scenarios. Recent studies have demonstrated that projections by alternative models can be so variable as to compromise their usefulness for guiding policy decisions. Here, we advocate the use of multiple models within an ensemble forecasting framework and describe alternative approaches to the analysis of bioclimatic ensembles, including bounding box, consensus and probabilistic techniques. We argue that, although improved accuracy can be delivered through the traditional tasks of trying to build better models with improved data, more robust forecasts can also be achieved if ensemble forecasts are produced and analysed appropriately.

  3. Core-satellite species hypothesis and native versus exotic species in secondary succession

    Science.gov (United States)

    Martinez, Kelsey A.; Gibson, David J.; Middleton, Beth A.

    2015-01-01

    A number of hypotheses exist to explain species’ distributions in a landscape, but these hypotheses are not frequently utilized to explain the differences in native and exotic species distributions. The core-satellite species (CSS) hypothesis predicts species occupancy will be bimodally distributed, i.e., many species will be common and many species will be rare, but does not explicitly consider exotic species distributions. The parallel dynamics (PD) hypothesis predicts that regional occurrence patterns of exotic species will be similar to native species. Together, the CSS and PD hypotheses may increase our understanding of exotic species’ distribution relative to natives. We selected an old field undergoing secondary succession to study the CSS and PD hypotheses in conjunction with each other. The ratio of exotic to native species (richness and abundance) was observed through 17 years of secondary succession. We predicted species would be bimodally distributed and that exotic:native species ratios would remain steady or decrease through time under frequent disturbance. In contrast to the CSS and PD hypotheses, native species occupancies were not bimodally distributed at the site, but exotic species were. The exotic:native species ratios for both richness (E:Nrichness) and abundance (E:Ncover) generally decreased or remained constant throughout supporting the PD hypothesis. Our results suggest exotic species exhibit metapopulation structure in old field landscapes, but that metapopulation structures of native species are disrupted, perhaps because these species are dispersal limited in the fragmented landscape.

  4. The nuclear question: rethinking species importance in multi-species animal groups.

    Science.gov (United States)

    Srinivasan, Umesh; Raza, Rashid Hasnain; Quader, Suhel

    2010-09-01

    1. Animals group for various benefits, and may form either simple single-species groups, or more complex multi-species associations. Multi-species groups are thought to provide anti-predator and foraging benefits to participant individuals. 2. Despite detailed studies on multi-species animal groups, the importance of species in group initiation and maintenance is still rated qualitatively as 'nuclear' (maintaining groups) or 'attendant' (species following nuclear species) based on species-specific traits. This overly simplifies and limits understanding of inherently complex associations, and is biologically unrealistic, because species roles in multi-species groups are: (i) likely to be context-specific and not simply a fixed species property, and (ii) much more variable than this dichotomy indicates. 3. We propose a new view of species importance (measured as number of inter-species associations), along a continuum from 'most nuclear' to 'least nuclear'. Using mixed-species bird flocks from a tropical rainforest in India as an example, we derive inter-species association measures from randomizations on bird species abundance data (which takes into account species 'availability') and data on 86 mixed-species flocks from two different flock types. Our results show that the number and average strength of inter-species associations covary positively, and we argue that species with many, strong associations are the most nuclear. 4. From our data, group size and foraging method are ecological and behavioural traits of species that best explain nuclearity in mixed-species bird flocks. Parallels have been observed in multi-species fish shoals, in which group size and foraging method, as well as diet, have been shown to correlate with nuclearity. Further, the context in which multi-species groups occur, in conjunction with species-specific traits, influences the role played by a species in a multi-species group, and this highlights the importance of extrinsic factors in

  5. Ecological impacts of non-native species

    Science.gov (United States)

    Wilkinson, John W.

    2012-01-01

    Non-native species are considered one of the greatest threats to freshwater biodiversity worldwide (Drake et al. 1989; Allen and Flecker 1993; Dudgeon et al. 2005). Some of the first hypotheses proposed to explain global patterns of amphibian declines included the effects of non-native species (Barinaga 1990; Blaustein and Wake 1990; Wake and Morowitz 1991). Evidence for the impact of non-native species on amphibians stems (1) from correlative research that relates the distribution or abundance of a species to that of a putative non-native species, and (2) from experimental tests of the effects of a non-native species on survival, growth, development or behaviour of a target species (Kats and Ferrer 2003). Over the past two decades, research on the effects of non-native species on amphibians has mostly focused on introduced aquatic predators, particularly fish. Recent research has shifted to more complex ecological relationships such as influences of sub-lethal stressors (e.g. contaminants) on the effects of non-native species (Linder et al. 2003; Sih et al. 2004), non-native species as vectors of disease (Daszak et al. 2004; Garner et al. 2006), hybridization between non-natives and native congeners (Riley et al. 2003; Storfer et al. 2004), and the alteration of food-webs by non-native species (Nystrom et al. 2001). Other research has examined the interaction of non-native species in terms of facilitation (i.e. one non-native enabling another to become established or spread) or the synergistic effects of multiple non-native species on native amphibians, the so-called invasional meltdown hypothesis (Simerloff and Von Holle 1999). Although there is evidence that some non-native species may interact (Ricciardi 2001), there has yet to be convincing evidence that such interactions have led to an accelerated increase in the number of non-native species and cumulative impacts are still uncertain (Simberloff 2006). Applied research on the control, eradication, and

  6. Microbial species delineation using whole genome sequences.

    Science.gov (United States)

    Varghese, Neha J; Mukherjee, Supratim; Ivanova, Natalia; Konstantinidis, Konstantinos T; Mavrommatis, Kostas; Kyrpides, Nikos C; Pati, Amrita

    2015-08-18

    Increased sequencing of microbial genomes has revealed that prevailing prokaryotic species assignments can be inconsistent with whole genome information for a significant number of species. The long-standing need for a systematic and scalable species assignment technique can be met by the genome-wide Average Nucleotide Identity (gANI) metric, which is widely acknowledged as a robust measure of genomic relatedness. In this work, we demonstrate that the combination of gANI and the alignment fraction (AF) between two genomes accurately reflects their genomic relatedness. We introduce an efficient implementation of AF,gANI and discuss its successful application to 86.5M genome pairs between 13,151 prokaryotic genomes assigned to 3032 species. Subsequently, by comparing the genome clusters obtained from complete linkage clustering of these pairs to existing taxonomy, we observed that nearly 18% of all prokaryotic species suffer from anomalies in species definition. Our results can be used to explore central questions such as whether microorganisms form a continuum of genetic diversity or distinct species represented by distinct genetic signatures. We propose that this precise and objective AF,gANI-based species definition: the MiSI (Microbial Species Identifier) method, be used to address previous inconsistencies in species classification and as the primary guide for new taxonomic species assignment, supplemented by the traditional polyphasic approach, as required. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  7. Alien species on the coasts of Turkey

    Directory of Open Access Journals (Sweden)

    M.E. CINAR

    2005-12-01

    Full Text Available The compilation of data on alien species reported from the Turkish coasts yielded a total of 263 species belonging to 11 systematic groups, of which Mollusca had the highest number of species (85 species, followed by Crustacea (51, fishes (43 and phytobenthos (39. The Black Sea is represented by a total of 20 alien species, the Sea of Marmara by 48 species, the Aegean Sea by 98 species and the Levantine Sea by 202 species. The majority of aliens found in the Black Sea and the Sea of Marmara were transported via shipping, whereas the Levantine coast is extensively subjected to Lessepsian migration. Benthic habitats (soft and hard substrata comprise 76% of the total alien species and the pelagic environment is inhabited by thirty-nine species. Almost 50% of aliens collected from the Turkish coasts were found only at 0-10 m depth. Eight species occur at depths deeper than 100 m. The impacts of aliens on the benthic and pelagic ecosystems are presented.

  8. Genomic definition of species. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    Crkvenjakov, R.; Drmanac, R.

    1993-03-01

    A genome is the sum total of the DNA sequences in the cells of an individual organism. The common usage that species possess genomes comes naturally to biochemists, who have shown that all protein and nucleic acid molecules are at the same time species- and individual-specific, with minor individual variations being superimposed on a consensus sequence that is constant for a species. By extension, this property is attributed to the common features of DNA in the chromosomes of members of a given species and is called species genome. Our proposal for the definition of a biological species is as follows: A species comprises a group of actual and potential biological organisms built according to a unique genome program that is recorded, and at least in part expressed, in the structures of their genomic nucleic acid molecule(s), having intragroup sequence differences which can be fully interconverted in the process of organismal reproduction.

  9. Genomic definition of species. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Crkvenjakov, R.; Dramanac, R.

    1992-06-01

    A genome is the sum total of the DNA sequences in the cells of an individual organism. The common usage that species possess genomes comes naturally to biochemists, who have shown that all protein and nucleic acid molecules are at the same time species and individual-specific, with minor individual variations being superimposed on a consensus sequence that is constant for a species. By extension, this property is attributed to the common features of DNA in the chromosomes of members of a given species and is called (species) genome. The definition of species based on chromosomes, genes, or genome common to its member organisms has been implied or mentioned in passing numerous times. Some population biologists think that members of species have similar ``homeostatic genotypes,`` which are to a degree resistant to mutation or environmental change in the production of a basic phenotype.

  10. Sea Cucumber (Holothuroidea Species of Turkey

    Directory of Open Access Journals (Sweden)

    Mehmet AYDIN

    2016-11-01

    Full Text Available There are nearly 1200 sea cucumber species in the world oceans, while only 37 species from Holothuroidea class lives in the Mediterranean Sea. This preliminary study aims identification sea cucumbers species of the Turkish waters. The sea cucumber samples used in this study were obtained from a series of different studies between the years of 2008 and 2014. Identification of the species are mainly based on the morphometric characteristics while some of species are determined from their calcareous spicules. Eight sea species were identified in this research which are; Holothuria tubulosa, Holothuria polii, Holothuria mammata, Holothuria (Platyperona sanctori, Holothuria forskali, Stichopus regalis, Synaptula reciprocans and Stereoderma kirschbergi. There are limited number of studies in the literature focusing on the identification of the sea cucumber species spread in our seas. Therefore, this study is believed to play an important role in guiding future researches.

  11. Fisheries oceanography of northern pelagic fish species

    DEFF Research Database (Denmark)

    Tsoukali, Stavroula

    for marine organisms. One of the impacts will be the time that species start to spawn, and there is already evidence for earlier spawning in some North Sea fish species. A change like that may likely have a chain reaction, affecting larval stages and whether they will live in environments with high food...... of the species they consume now and increased availability of new species. In addition, there will likely be economic impacts on the local fishing communities. How species respond to climate change is a field of research that receives great attention because the responses will affect the management of fisheries......People are familiar with marine fish species and the great variety of different species that are available in the market, such as herring, cod and sole. What may not be well known is that every individual fish goes through a long, risky journey during its life before reaching maturity. Most...

  12. Four new species of Pteromalus Swederus (Hymenoptera: Chalcidoidea: Pteromalidae) and redescriptions of three other species

    NARCIS (Netherlands)

    Gijswijt, M.J.

    1999-01-01

    A key to the European species of the Pteromalus altus group is presented. The relationship between this group and species of the genus Euphorbia (Euphorbiaceae) is confirmed. One new species: P. villosae, associated with Euphorbia villosa Waldst. & Kit.is presented. Two new species of the albipennis

  13. Palpi aplenty: New species in the Chrysotus longipalpus species group (Diptera: Dolichopodidae)

    Science.gov (United States)

    Justin B. Runyon; Renato S. Capellari

    2018-01-01

    Four new Nearctic species belonging to the Chrysotus longipalpus species group are described: Chrysotus keyensis sp. nov. (Florida), Chrysotus mccreadiei sp. nov. (Alabama), Chrysotus mystax sp. nov. (Alabama), and Chrysotus plumarista sp. nov. (Alabama). This brings the number of known species in this group to twelve. A key to species of males of the C. longipalpus...

  14. A globally-distributed alien invasive species poses risks to United States imperiled species.

    Science.gov (United States)

    McClure, Meredith L; Burdett, Christopher L; Farnsworth, Matthew L; Sweeney, Steven J; Miller, Ryan S

    2018-03-28

    In the midst of Earth's sixth mass extinction event, non-native species are a driving factor in many imperiled species' declines. One of the most widespread and destructive alien invasive species in the world, wild pigs (Sus scrofa) threaten native species through predation, habitat destruction, competition, and disease transmission. We show that wild pigs co-occur with up to 87.2% of imperiled species in the contiguous U.S. identified as susceptible to their direct impacts, and we project increases in both the number of species at risk and the geographic extent of risks by 2025. Wild pigs may therefore present a severe threat to U.S. imperiled species, with serious implications for management of at-risk species throughout wild pigs' global distribution. We offer guidance for efficient allocation of research effort and conservation resources across species and regions using a simple approach that can be applied to wild pigs and other alien invasive species globally.

  15. Bacillus cereus and related species.

    Science.gov (United States)

    Drobniewski, F A

    1993-10-01

    Bacillus cereus is a gram-positive aerobic or facultatively anaerobic spore-forming rod. It is a cause of food poisoning, which is frequently associated with the consumption of rice-based dishes. The organism produces an emetic or diarrheal syndrome induced by an emetic toxin and enterotoxin, respectively. Other toxins are produced during growth, including phospholipases, proteases, and hemolysins, one of which, cereolysin, is a thiol-activated hemolysin. These toxins may contribute to the pathogenicity of B. cereus in nongastrointestinal disease. B. cereus isolated from clinical material other than feces or vomitus was commonly dismissed as a contaminant, but increasingly it is being recognized as a species with pathogenic potential. It is now recognized as an infrequent cause of serious nongastrointestinal infection, particularly in drug addicts, the immunosuppressed, neonates, and postsurgical patients, especially when prosthetic implants such as ventricular shunts are inserted. Ocular infections are the commonest types of severe infection, including endophthalmitis, panophthalmitis, and keratitis, usually with the characteristic formation of corneal ring abscesses. Even with prompt surgical and antimicrobial agent treatment, enucleation of the eye and blindness are common sequelae. Septicemia, meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections are other manifestations of severe disease. B. cereus produces beta-lactamases, unlike Bacillus anthracis, and so is resistant to beta-lactam antibiotics; it is usually susceptible to treatment with clindamycin, vancomycin, gentamicin, chloramphenicol, and erythromycin. Simultaneous therapy via multiple routes may be required.

  16. Antibiotic resistance in Burkholderia species.

    Science.gov (United States)

    Rhodes, Katherine A; Schweizer, Herbert P

    2016-09-01

    The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Species longevity in North American fossil mammals.

    Science.gov (United States)

    Prothero, Donald R

    2014-08-01

    Species longevity in the fossil record is related to many paleoecological variables and is important to macroevolutionary studies, yet there are very few reliable data on average species durations in Cenozoic fossil mammals. Many of the online databases (such as the Paleobiology Database) use only genera of North American Cenozoic mammals and there are severe problems because key groups (e.g. camels, oreodonts, pronghorns and proboscideans) have no reliable updated taxonomy, with many invalid genera and species and/or many undescribed genera and species. Most of the published datasets yield species duration estimates of approximately 2.3-4.3 Myr for larger mammals, with small mammals tending to have shorter species durations. My own compilation of all the valid species durations in families with updated taxonomy (39 families, containing 431 genera and 998 species, averaging 2.3 species per genus) yields a mean duration of 3.21 Myr for larger mammals. This breaks down to 4.10-4.39 Myr for artiodactyls, 3.14-3.31 Myr for perissodactyls and 2.63-2.95 Myr for carnivorous mammals (carnivorans plus creodonts). These averages are based on a much larger, more robust dataset than most previous estimates, so they should be more reliable for any studies that need species longevity to be accurately estimated. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  18. A Theory of Flagship Species Action

    Directory of Open Access Journals (Sweden)

    Paul Jepson

    2015-01-01

    Full Text Available The flagship species approach is an enduring strategy in conservation. Academic discussion on flagship species has focussed on two dimensions: on what basis should they be selected and how have they been put to use. Here we consider a third dimension, namely the manner in which flagship species act and have the capacity to galvanise and influence conservation outcomes. Drawing on concepts from the social sciences, viz. affordance, framing, and actor-networks; we discuss examples of flagship species to propose a theory of flagship species action. In brief, our theory posits that a flagship species is one with traits that afford the assembly of relatively coherent networks of associations with ideational elements located in pre-existing cultural framings. These associations give rise to opportunities to align with deep cultural frames, contemporary cultural phenomena and political economy such that when a conservation action is introduced, forms of agency cause the species and human publics to change. The species becomes re-framed (or reinvigorated as a cultural asset speaking for a wider nature, publics and political agendas. Further our theory posits that species with traits that enrol in idea networks incorporating human fears, will have limited flagship capacity. This is because the ability of the representations produced to align with frames incorporating collective aspirations is constrained. In terms of applied conservation practice, our theory suggests that: a key criteria for selecting potential flagship species is presence in existing cultural frames, that effective deployment of flagship species requires an understanding of the species′ cultural associations, and a species ability to galvanise action may be limited to certain times and places. Furthermore, once deployed conservation interests will never have full control over the flagship species: it may act in uncertain and unexpected ways.

  19. Competition between species of small mammals

    International Nuclear Information System (INIS)

    Grant, P.R.

    1978-01-01

    Interspecific competition has often been inferred from its results. In evolutionary time it has been responsible for patterns of regularity in the structure of mammalian communities, and in the morphological and ecological characteristics of the constituent species. In contemporary time it gives rise to reciprocal (complementary) numbers and distributions of two or more species. These inferences are strengthened by recent experimental demonstrations of competition between species of North American rodents. Recent observations and experiments are reviewed. The most thoroughly studied competitors are two species of microtine rodents, Microtus pennsylvanicus and Clethrionomys gapperi. Species which compete for space have been studied experimentally more often than have food competitors. Overt aggression is frequently implicated, but its importance in nature in relation to other means of interaction (e.g. through vocal or scent communication) is not known. The definitive study of competition for food between mammal species has yet to be performed

  20. Radiation protection of non-human species

    International Nuclear Information System (INIS)

    Leith, I.S.

    1993-01-01

    The effects of radiation on non-human species, both animals and plants, have long been investigated. In the disposal of radioactive wastes, the protection of non-human species has been investigated. Yet no radiation protection standard for exposure of animals and plants per se has been agreed. The International Commission on Radiological Protection has long taken the view that, if human beings are properly protected from radiation, other species will thereby be protected to the extent necessary for their preservation. However, the International Atomic Energy Agency has found it necessary to investigate the protection of non-human species where radioactivity is released to an environment unpopulated by human beings. It is proposed that the basis of such protection, and the knowledge of radiation effects on non-human species on which it is based, suggest a practical radiation protection standard for non-human species. (1 tab.)

  1. On the Mass Distribution of Animal Species

    Science.gov (United States)

    Redner, Sidney; Clauset, Aaron; Schwab, David

    2009-03-01

    We develop a simple diffusion-reaction model to account for the broad and asymmetric distribution of adult body masses for species within related taxonomic groups. The model assumes three basic evolutionary features that control body mass: (i) a fixed lower limit that is set by metabolic constraints, (ii) a species extinction risk that is a weakly increasing function of body mass, and (iii) cladogenetic diffusion, in which daughter species have a slight tendency toward larger mass. The steady-state solution for the distribution of species masses in this model can be expressed in terms of the Airy function. This solution gives mass distributions that are in good agreement with data on 4002 terrestrial mammal species from the late Quaternary and 8617 extant bird species.

  2. Aging and immortality in unicellular species.

    Science.gov (United States)

    Florea, Michael

    2017-10-01

    It has been historically thought that in conditions that permit growth, most unicellular species do not to age. This was particularly thought to be the case for symmetrically dividing species, as such species lack a clear distinction between the soma and the germline. Despite this, studies of the symmetrically dividing species Escherichia coli and Schizosaccharomyces pombe have recently started to challenge this notion. They indicate that E. coli and S. pombe do age, but only when subjected to environmental stress. If true, this suggests that aging may be widespread among microbial species in general, and that studying aging in microbes may inform other long-standing questions in aging. This review examines the recent evidence for and against replicative aging in symmetrically dividing unicellular organisms, the mechanisms that underlie aging, why aging evolved in these species, and how microbial aging fits into the context of other questions in aging. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Costs Associated with Endangered Species Act Compliance

    Science.gov (United States)

    2013-08-01

    August 2013 2 on economic costs or values related to endangered species costs or values, focuses primarily on Contingent Valuation Method studies...of species preservation (Lew, Layton, and Rowe 2010; Wallmo 2006). Most studies consider public valuation of species preservation, and not costs of...2012, NMFS 2006, U.S. Army Engineer, Mississippi Valley Division 2012, Kozlowski 1993, PFMC 2002) and through development of expenditure categories

  4. The transformer species of the Ukrainian Polissya

    Directory of Open Access Journals (Sweden)

    Protopopova Vira V.

    2015-09-01

    Full Text Available The investigation results of the transformer species participation (Echinocystis lobata (Michx. Torr. & A. Gray, Heracleum sosnowskyi Manden., Impatiens glandulifera Royle, I. parviflora DC., Reynoutria japonica Houtt., Robinia pseudoacacia L. in different plant communities of the Ukrainian Polissya (Forest zone of Ukraine are presented. All the abovementioned species are strong edificators in the region that can significantly change important species composition parameters of communities and character of landscape.

  5. Species - San Diego Co. [ds121

    Data.gov (United States)

    California Natural Resource Agency — This is the Biological Observation Database point layer representing baseline observations of sensitive species (as defined by the MSCP) throughout San Diego County....

  6. Biological species in the viral world.

    Science.gov (United States)

    Bobay, Louis-Marie; Ochman, Howard

    2018-06-05

    Due to their dependence on cellular organisms for metabolism and replication, viruses are typically named and assigned to species according to their genome structure and the original host that they infect. But because viruses often infect multiple hosts and the numbers of distinct lineages within a host can be vast, their delineation into species is often dictated by arbitrary sequence thresholds, which are highly inconsistent across lineages. Here we apply an approach to determine the boundaries of viral species based on the detection of gene flow within populations, thereby defining viral species according to the biological species concept (BSC). Despite the potential for gene transfer between highly divergent genomes, viruses, like the cellular organisms they infect, assort into reproductively isolated groups and can be organized into biological species. This approach revealed that BSC-defined viral species are often congruent with the taxonomic partitioning based on shared gene contents and host tropism, and that bacteriophages can similarly be classified in biological species. These results open the possibility to use a single, universal definition of species that is applicable across cellular and acellular lifeforms.

  7. Use of species-specific PCR for the identification of 10 sea cucumber species

    Science.gov (United States)

    Wen, Jing; Zeng, Ling

    2014-11-01

    We developed a species-specific PCR method to identify species among dehydrated products of 10 sea cucumber species. Ten reverse species-specific primers designed from the 16S rRNA gene, in combination with one forward universal primer, generated PCR fragments of ca. 270 bp length for each species. The specificity of the PCR assay was tested with DNA of samples of 21 sea cucumber species. Amplification was observed in specific species only. The species-specific PCR method we developed was successfully applied to authenticate species of commercial products of dehydrated sea cucumber, and was proven to be a useful, rapid, and low-cost technique to identify the origin of the sea cucumber product.

  8. Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands

    Science.gov (United States)

    Keeley, Jon E.

    2003-01-01

    Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species-area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m2) exhibit different species-area relationships and different species abundance patterns. The species-area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species-area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small-stature annual species in California and the lack of annuals in Australian heathlands. Species-area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species-area curves initially rise rapidly between 1 and 100 m2. Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m2 but more rapidly between 100 and 1000 m2due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species-area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species-area curves, and this may be tied to patterns of life form distribution.

  9. Population genetic structure of the lettuce root aphid, Pemphigus bursarius (L.), in relation to geographic distance, gene flow and host plant usage.

    Science.gov (United States)

    Miller, N J; Birley, A J; Overall, A D J; Tatchell, G M

    2003-09-01

    Microsatellite markers were used to examine the population structure of Pemphigus bursarius, a cyclically parthenogenetic aphid. Substantial allele frequency differences were observed between populations on the primary host plant (collected shortly after sexual reproduction) separated by distances as low as 14 km. This suggested that migratory movements occur over relatively short distances in this species. However, the degree of allele frequency divergence between populations was not correlated with their geographical separation, indicating that isolation by distance was not the sole cause of spatial genetic structuring. Significant excesses of homozygotes were observed in several populations. Substantial allele frequency differences were also found between aphids on the primary host and those sampled from a secondary host plant after several parthenogenetic generations at the same location in two successive years. This could have been due to the existence of obligately parthenogenetic lineages living on the secondary host or genetically divergent populations confined to different secondary host plant species but sharing a common primary host.

  10. Two new species of nocturnal bees of the genus Megalopta (Hymenoptera: Halictidae) with keys to species.

    Science.gov (United States)

    Gonzalez, Victor H; Griswold, Terry; Ayala, Ricardo

    2010-03-01

    Megalopta Smith, 1853, is a Neotropical genus of nocturnal or crepuscular bees. Two subgenera are recognized with most of its nearly 30 species placed in the nominate subgenus. Species of Megalopta s. str. are more commonly collected than species of Noctoraptor Engel et al. 1997, all presumably parasites of Megalopta s. str. Two new species of Megalopta are described here: M. (Megalopta) tetewana, n. sp., from Mexico and M. (Noctoraptor) huaoranii, n. sp., from Ecuador. Identification keys to the Central American species of Megalopta s. str. and the species of the parasitic subgenus Noctoraptor are presented.

  11. The species velocity of trees in Alaska

    Science.gov (United States)

    Morrison, B. D.; Napier, J.; de Lafontaine, G.; Heath, K.; Li, B.; Hu, F.; Greenberg, J. A.

    2017-12-01

    Anthropogenic climate change has motivated interest in the paleo record to enhance our knowledge about past vegetation responses to climate change and help understand potential responses in the future. Additionally, polar regions currently experience the most rapid rates of climate change globally, prompting concern over changes in the ecological composition of high latitude ecosystems. Recent analyses have attempted to construct methods to estimate a species' ability to track climate change by computing climate velocity; a measure of the rate of climate displacement across a landscape which may indicate the speed an organism must migrate to keep pace with climate change. However, a challenge to using climate velocity in understanding range shifts is a lack of species-specificity in the velocity calculations: climate velocity does not actually use any species data in its analysis. To solve the shortcomings of climate velocity in estimating species displacement rates, we computed the "species velocity" of white spruce, green and grey alder populations across the state of Alaska from the Last Glacial Maximum (LGM) to today. Species velocity represents the rate and direction a species is required to migrate to keep pace with a changing climate following the LGM. We used a species distribution model to determine past and present white spruce and alder distributions using statistically downscaled climate data at 60m. Species velocity was then derived from the change in species distribution per year by the change in distribution over Alaska (km/yr). High velocities indicate locations where the species environmental envelope is changing drastically and must disperse rapidly to survive climate change. As a result, high velocity regions are more vulnerable to distribution shifts and higher risk of local extinction. Conversely, low species velocities indicate locations where the local climate envelope is shifting relatively slowly, reducing the stress to disperse quickly

  12. Evaluating species richness: biased ecological inference results from spatial heterogeneity in species detection probabilities

    Science.gov (United States)

    McNew, Lance B.; Handel, Colleen M.

    2015-01-01

    Accurate estimates of species richness are necessary to test predictions of ecological theory and evaluate biodiversity for conservation purposes. However, species richness is difficult to measure in the field because some species will almost always be overlooked due to their cryptic nature or the observer's failure to perceive their cues. Common measures of species richness that assume consistent observability across species are inviting because they may require only single counts of species at survey sites. Single-visit estimation methods ignore spatial and temporal variation in species detection probabilities related to survey or site conditions that may confound estimates of species richness. We used simulated and empirical data to evaluate the bias and precision of raw species counts, the limiting forms of jackknife and Chao estimators, and multi-species occupancy models when estimating species richness to evaluate whether the choice of estimator can affect inferences about the relationships between environmental conditions and community size under variable detection processes. Four simulated scenarios with realistic and variable detection processes were considered. Results of simulations indicated that (1) raw species counts were always biased low, (2) single-visit jackknife and Chao estimators were significantly biased regardless of detection process, (3) multispecies occupancy models were more precise and generally less biased than the jackknife and Chao estimators, and (4) spatial heterogeneity resulting from the effects of a site covariate on species detection probabilities had significant impacts on the inferred relationships between species richness and a spatially explicit environmental condition. For a real dataset of bird observations in northwestern Alaska, the four estimation methods produced different estimates of local species richness, which severely affected inferences about the effects of shrubs on local avian richness. Overall, our results

  13. Species-specific associations between overstory and understory tree species in a semideciduous tropical forest

    Directory of Open Access Journals (Sweden)

    Flaviana Maluf Souza

    2015-03-01

    Full Text Available We investigated the occurrence of associations between overstory and understory tree species in a semideciduous tropical forest. We identified and measured all trees of nine canopy species with diameter at breast height ≥4.8 cm in a 10.24 ha plot and recorded all individuals beneath their canopies ("understory individuals" within the same diameter class. The total density of understory individuals did not significantly differ under different overstory species. One overstory species (Ceiba speciosa showed higher understory species richness compared with five other species. There was a strong positive association between three overstory species (Esenbeckia leiocarpa, Savia dictyocarpa, and C. speciosa and the density of seven understory species (Balfourodendron riedelianum, Chrysophyllum gonocarpum, E. leiocarpa, Holocalyx balansae, Machaerium stipitatum, Rhaminidium elaeocarpum, and S. dictyocarpa. These results probably reflect the outcome of a complex set of interactions including facilitation and competition, and further studies are necessary to better understand the magnitude and type of the effects of individual overstory species on understory species. The occurrence of species-specific associations shown here reinforces the importance of non-random processes in structuring plant communities and suggest that the influence of overstory species on understory species in high-diversity forests may be more significant than previously thought.

  14. New Species of Orchids from Vietnam

    Directory of Open Access Journals (Sweden)

    Leonid V. Averyanov

    2007-12-01

    Full Text Available Identification of herbarium specimens collected in course of field exploration works in Vietnam during 2005-2007 revealed ten species of orchids new for science. Illustrated descriptions are provided for each discovered species, which are named as Anoectochilus papillosus, Arundina caespitosa, Bulbophyllum paraemarginatum, B. sinhoënse, Cheirostylis foliosa, Goodyera rhombodoides, Liparis rivularis, Oberonia multidentata, O. trichophora and Sunipia nigricans.

  15. Xanthomendoza borealis - a bipolar lichen species

    DEFF Research Database (Denmark)

    LIndblom, Louise; Søchting, Ulrik

    It has been uncertain whether the two xanthorioid taxa known as Xanthoria mawsonii and Xanthomen-doza borealis truly are distinct species or if they should best be treated as one species. They are morphologically very similar, but inhabit two disjunct geographical areas, that is, circumpolar on t...

  16. Rapid molecular technique to distinguish Fusarium species

    CSIR Research Space (South Africa)

    Lodolo, EJ

    1993-03-01

    Full Text Available The nuclear DNA (nDNA) of different isolates of three closely related, toxin-producing Fusarium species, F. moniliforme, F. nygamai and F. napiforme, was compared to ascertain the sensitivity of a molecular method to distinguish these three species...

  17. Antibiotic susceptibilities of Salmonella species prevalent among ...

    African Journals Online (AJOL)

    This study was conducted to assess the prevalence of Salmonella species among children having diarrhea in Katsina State, Nigeria. A total of 220 diarrhea stool samples of children aged five years and below (0-5 years) were collected and screened for Salmonella species using culture technique. Presumptively positive ...

  18. In vitro propagation of Fraxinus species

    Science.gov (United States)

    J.W. Van Sambeek; J.E. Preece

    2007-01-01

    The genus Fraxinus, a member of the Oleaceae family, includes over 65 ash species native to the temperate regions of the northern hemisphere (Miller, 1955). Several of the ash species are important forest trees noted for their tough, highly resistant to shock, straight grained wood as well as being excellent shade trees for parks and residential...

  19. Molecular characterization of thermophilic Campylobacter species ...

    African Journals Online (AJOL)

    We identified two species of thermophilic Campylobacter in companion dogs in Jos. Majority of C. jejuni were isolated from mucoid faeces while mixed infections of the two species were more common among diarrhoeic dogs. Pet owners should observe strict hand hygiene especially after handling dogs or their faeces to ...

  20. Two New American Species of Hordeum (Poaceae)

    DEFF Research Database (Denmark)

    Bothmer, Roland Von; Jacobsen, Niels; Bagger Jørgensen, Rikke

    1985-01-01

    Two new species of Hordeum are described, viz. the diploid H. erectifolium, native to Argentina, and H. guatemalense, native to Guatemala.......Two new species of Hordeum are described, viz. the diploid H. erectifolium, native to Argentina, and H. guatemalense, native to Guatemala....

  1. New and noteworthy Malesian species of Loranthaceae

    NARCIS (Netherlands)

    Barlow, Bryan A.

    1995-01-01

    Ten new or noteworthy Malesian species of Loranthaceae are discussed. The known area of the relictual Cecarria obtusifolia (Merrill) Barlow is increased to include Flores and Timor. Dendrophthoe curvata (Blume) Miquel is accepted as a distinct species. The status of Dendrophthoe falcata (L. f.)

  2. On two new species of Cercopithecus

    NARCIS (Netherlands)

    Jentink, F.A.

    1886-01-01

    In 1877 our Museum received a Cercopithecus died in the Zoological Garden at Rotterdam. Professor Schlegel thought it to be a new species and called it Cercopithecus signatus, but he never described it. As it seems to me to be a very good species I describe it under the name given by Schlegel. It

  3. Species diversity of Trichoderma in Poland

    Science.gov (United States)

    Fifteen species of Trichoderma were identified from among 118 strains originating from different regions and ecological niches in Poland. This low number indicates low species diversity of Trichoderma in this Central European region. Using the ITS1-ITS2 regions, 64 strains were positively identified...

  4. Prevalence of Cryptosporidium species and Giardia intestinalis ...

    African Journals Online (AJOL)

    Cryptosporidium species and Giardia intestinalis cause diarrheal infections in humans and other vertebrate animals globally and are considered to be of great public health importance. The study was conducted to determine the prevalence Cryptosporidium species and G. intestinalis infections among patients attending ...

  5. New species of haematozoa in Phalacrocoracidae and ...

    African Journals Online (AJOL)

    New species of haematozoa, namely Leucocytozoon ugwidi sp. nov. from the Cape Cormorant Phalacrocorax capensis and Haemoproteus skuae sp. nov. from the Subantarctic Skua Catharacta antarctica, are described. These are the first species to be recorded from the families Phalacrocoracidae and Stercorariidae, ...

  6. Metabolite production by differnt Ulocladium species

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Hollensted, Morten

    2008-01-01

    Ulocladium, which is phylogenetically related to Alternaria, contains species that are food spoilers and plant pathogens, but also species that have potential as enzyme producers and bio-control agents. Ulocladium spp. are often found on dead vegetation, in soil, air and dust, but also on food...

  7. Species hybridization in the genus Pinus

    Science.gov (United States)

    Peter W. Garrett

    1979-01-01

    Results of a breeding program in which a large number of pine species were tested indicate that a number of species and hybrids may be useful in the northeastern United States. Austrian black pine x Japanese black pine and hybrids containing Japanese red pine all had good growth rates. While none of the soft pines grew faster than eastern white pine, a number of...

  8. Toward reassessing data-deficient species.

    Science.gov (United States)

    Bland, Lucie M; Bielby, Jon; Kearney, Stephen; Orme, C David L; Watson, James E M; Collen, Ben

    2017-06-01

    One in 6 species (13,465 species) on the International Union for Conservation of Nature (IUCN) Red List is classified as data deficient due to lack of information on their taxonomy, population status, or impact of threats. Despite the chance that many are at high risk of extinction, data-deficient species are typically excluded from global and local conservation priorities, as well as funding schemes. The number of data-deficient species will greatly increase as the IUCN Red List becomes more inclusive of poorly known and speciose groups. A strategic approach is urgently needed to enhance the conservation value of data-deficient assessments. To develop this, we reviewed 2879 data-deficient assessments in 6 animal groups and identified 8 main justifications for assigning data-deficient status (type series, few records, old records, uncertain provenance, uncertain population status or distribution, uncertain threats, taxonomic uncertainty, and new species). Assigning a consistent set of justification tags (i.e., consistent assignment to assessment justifications) to species classified as data deficient is a simple way to achieve more strategic assessments. Such tags would clarify the causes of data deficiency; facilitate the prediction of extinction risk; facilitate comparisons of data deficiency among taxonomic groups; and help prioritize species for reassessment. With renewed efforts, it could be straightforward to prevent thousands of data-deficient species slipping unnoticed toward extinction. © 2016 Society for Conservation Biology.

  9. Preliminary observations on the species composition and ...

    African Journals Online (AJOL)

    Majority of the mushrooms appear during the rain season and are equally available during the short and long rains. This suggests that most species will grow well throughout the year whenever moisture level in the substrate is adequate irrespective of the season. Some of the species especially the Polypores (Ganoderma ...

  10. Taxonomy of Penicillium citrinum and related species

    NARCIS (Netherlands)

    Houbraken, J.; Frisvad, J.C.; Samson, R.A.

    2010-01-01

    Penicillium citrinum and related species have been examined using a combination of partial beta-tubulin, calmodulin and ITS sequence data, extrolite patterns and phenotypic characters. It is concluded that seven species belong to the series Citrina. Penicillium sizovae and Penicillium steckii are

  11. Some new or noteworthy species of Mortierella

    NARCIS (Netherlands)

    Gams, W.

    1976-01-01

    Twenty-two species of Mortierella are described and distributed over the sections defined by Gams (1970) which include the following new species: Section Pusilla: M. roseo-nana; Section Alpina: M. globalpina and M. polygonia Section Simplex: M. amoeboidea; Section Hygrophila : M. elongatula, M.

  12. DNA species surveillance: Monitoring bushmeat poaching and ...

    African Journals Online (AJOL)

    DNA species identification has applications in such areas as forensic science, systematics, conservation genetics and agriculture. One key anthropogenic activity threatening large wildlife fauna is illegal exploitation. In Kenya, species identification of raw and processed meat products remains a constraint to effective ...

  13. Distribution of crayfish species in Hungarian waters

    NARCIS (Netherlands)

    Mercédesz, Ludányi; Peeters, E.T.H.M.; Kiss, B.; Roessink, I.

    2016-01-01

    Three native crayfish species, i.e.~Astacus astacus, Astacus leptodactylus and Austropotamobius torrentium, occur in Hungary. Lately, however, non-indigenous crustaceans have also invaded the country Their most recent distribution and impact on the occurrences of the native species is not clear.

  14. Grain Unloading Of Arsenic Species In Rice

    Science.gov (United States)

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dim...

  15. SERI Aquatic Species Program: 1983 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    1984-03-01

    During 1983 research was carried out under three tasks: biological, engineering, and analysis. Biological research was aimed at screening for promising species of microalgae, macroalgae, and emergent plants that could be cultivated for energy products. Promising species were studied further to improve yields.

  16. ENDANGERED SPECIES SENSITIVITY AND ECOLOGICAL RISK ASSESSMENT

    Science.gov (United States)

    he U.S. Environmental Protection Agency (EPA), U.S. Fish & Wildlife Service, and National Marine Fisheries Service share a common responsibility for the protection of our nation's aquatic species under the Endangered Species Act (ESA) of 1973. The EPA, under the Federal Insectici...

  17. antimicrobial susceptibility pattern of Salmonella species

    African Journals Online (AJOL)

    user

    ABSTRACT. Treatment of enteric fever is increasingly becoming very challenging due to the increasing wave of antibiotic resistance. This study is a review of the contemporary antimicrobial susceptibility pattern of. Salmonella species. The antimicrobial susceptibility pattern of Salmonella species to a wide range of.

  18. Endangered Species (Plants). LC Science Tracer Bullet.

    Science.gov (United States)

    Niskern, Diana, Comp.

    This guide is intended for those who wish to study the literature dealing with various aspects of endangered plant species. This document includes the following sections, some of which are bibliographies: (1) "Introductions to the Topic"; (2) "Subject Headings" (for endangered species of plants used by the Library of Congress); (3) "General…

  19. Endangered Species: Real Life in Two Dimensions

    Science.gov (United States)

    Henderson, Lynette K.

    2012-01-01

    The focus of "Endangered Species: Real Life in Two Dimensions" is to create awareness about a critical environmental issue. There is a special urgency to this project because large numbers of animal species are currently endangered or on the brink of extinction. In addition to being enlightened about this important topic through research, students…

  20. Multiple bacterial species reside in chronic wounds

    DEFF Research Database (Denmark)

    Gjødsbøl, Kristine; Christensen, Jens Jørgen; Karlsmark, Tonny

    2006-01-01

    species present were identified. More than one bacterial species were detected in all the ulcers. The most common bacteria found were Staphylococcus aureus (found in 93.5% of the ulcers), Enterococcus faecalis (71.7%), Pseudomonas aeruginosa (52.2%), coagulase-negative staphylococci (45.7%), Proteus...

  1. Multiplexed microsatellite markers for seven Metarhizium species

    Science.gov (United States)

    Cross-species transferability of 41 previously published simple sequence repeat (SSR) markers was assessed for 11 species of the entomopathogenic fungus Metarhizium. A collection of 65 Metarhizium isolates including all 54 used in a recent phylogenetic revision of the genus were characterized. Betwe...

  2. The Invasive Plant Species Education Guide

    Science.gov (United States)

    Mason, Kevin; James, Krista; Carlson, Kitrina; D'Angelo, Jean

    2010-01-01

    To help high school students gain a solid understanding of invasive plant species, university faculty and students from the University of Wisconsin-Stout (UW-Stout) and a local high school teacher worked together to develop the Invasive Plant Species (IPS) Education Guide. The IPS Education Guide includes nine lessons that give students an…

  3. The Drosophila bipectinata species complex: phylogenetic ...

    Indian Academy of Sciences (India)

    Navya

    *For Correspondence. e-mail: bashisthsingh2004@rediffmail.com, ... A species complex constitutes groups of closely related species which have diverged ..... there is a strong reproductive isolation too (See review by Singh and Banerjee 2016) .... figure both the loops touch the chromocenter and in our microphotograph ...

  4. CONSERVATION PROGRAMS THAT PROMOTE INVASIVE SPECIES

    Science.gov (United States)

    Invasive plant species are degrading the structure and function of ecosystems throughout the world. Although most state and federal conservation agencies in the U.S. attempt to reduce the impact of invasive species, some agency activities can contribute to the spread of invasive...

  5. Invasive plant species in hardwood tree plantations

    Science.gov (United States)

    Rochelle R. Beasley; Paula M. Pijut

    2010-01-01

    Invasive plants are species that can grow and spread aggressively, mature quickly, and invade an ecosystem causing economic and environmental damage. Invasive plants usually invade disturbed areas, but can also colonize small areas quickly, and may spread and dominate large areas in a few short years. Invasive plant species displace native or desirable forest...

  6. New species of Maerua (Capparaceae) from Angola

    NARCIS (Netherlands)

    Abreu, J.A.; Martins, E.S.; Catarino, L.

    2014-01-01

    Genus Maerua has around 60 species represented on the African continent, of which three have been reported for Angola. Two new species of Maerua (Capparaceae) from Angola are here described. Both are closely similar to M. juncea subsp. juncea, being distinguished by floral traits such as the

  7. 76 FR 30955 - Invasive Species Advisory Committee

    Science.gov (United States)

    2011-05-27

    ... Commerce. The duty of the Council is to provide national leadership regarding invasive species issues... broad array of issues related to preventing the introduction of invasive species and providing for their... with Western-based scientists and practitioners on problems and potential solutions, as well as...

  8. Fatal attraction: rare species in the spotlight.

    Science.gov (United States)

    Angulo, Elena; Deves, Anne-Laure; Saint Jalmes, Michel; Courchamp, Franck

    2009-04-07

    The exploitation of rare and endangered species can end in the species's extinction because the increased value people associate with rarity increases the economic incentive to exploit the last individuals, creating a positive feedback loop. This recently proposed concept, called the anthropogenic Allee effect (AAE), relies on the assumption that people do value rarity, but this remains to be established. Moreover, it also remains to be determined whether attraction to rarity is a trait confined to a minority of hobbyists (e.g. wildlife collectors, exotic pet owners) or characteristic of the general public. We estimated how much the general public valued rare species compared with common ones, using five different metrics related to personal investment: time spent, physical effort, unpleasantness, economic investment and risk. We surveyed the visitors of a zoo. To see the rare species, the visitors to the zoo invested more time in searching and contemplation, they were ready to expend more physical effort, they tolerated more unpleasant conditions, they were willing to pay more and, finally, they risked more to obtain (steal) a rare species. Our results provide substantial evidence of how the general public places more value on rare species, compared with common species. This confirms the AAE as an actual process, which in addition concerns a large part of the population. This has important consequences for the conservation of species that are rare now, or that could become so in the future.

  9. Characterization of Aspergillus species associated with ...

    African Journals Online (AJOL)

    About 82 triphala powder samples were analyzed for the association of different fungi. Results reveal the predominance of Aspergillus as the major genera with six predominant species namely, A. niger, A. flavus, A. fumigatus, A. terreus, A. nidulans and A. amstelodami. Therefore, these six isolated Aspergillus species were ...

  10. Novel Pestivirus Species in Pigs, Austria, 2015.

    Science.gov (United States)

    Lamp, Benjamin; Schwarz, Lukas; Högler, Sandra; Riedel, Christiane; Sinn, Leonie; Rebel-Bauder, Barbara; Weissenböck, Herbert; Ladinig, Andrea; Rümenapf, Till

    2017-07-01

    A novel pestivirus species was discovered in a piglet-producing farm in Austria during virologic examinations of congenital tremor cases. The emergence of this novel pestivirus species, provisionally termed Linda virus, in domestic pigs may have implications for classical swine fever virus surveillance and porcine health management.

  11. Emergent neutrality drives phytoplankton species coexistence

    Science.gov (United States)

    Segura, Angel M.; Calliari, Danilo; Kruk, Carla; Conde, Daniel; Bonilla, Sylvia; Fort, Hugo

    2011-01-01

    The mechanisms that drive species coexistence and community dynamics have long puzzled ecologists. Here, we explain species coexistence, size structure and diversity patterns in a phytoplankton community using a combination of four fundamental factors: organism traits, size-based constraints, hydrology and species competition. Using a ‘microscopic’ Lotka–Volterra competition (MLVC) model (i.e. with explicit recipes to compute its parameters), we provide a mechanistic explanation of species coexistence along a niche axis (i.e. organismic volume). We based our model on empirically measured quantities, minimal ecological assumptions and stochastic processes. In nature, we found aggregated patterns of species biovolume (i.e. clumps) along the volume axis and a peak in species richness. Both patterns were reproduced by the MLVC model. Observed clumps corresponded to niche zones (volumes) where species fitness was highest, or where fitness was equal among competing species. The latter implies the action of equalizing processes, which would suggest emergent neutrality as a plausible mechanism to explain community patterns. PMID:21177680

  12. Finessing atlas data for species distribution models

    NARCIS (Netherlands)

    Niamir, A.; Skidmore, A.K.; Toxopeus, A.G.; Munoz, A.R.; Real, R.

    2011-01-01

    Aim The spatial resolution of species atlases and therefore resulting model predictions are often too coarse for local applications. Collecting distribution data at a finer resolution for large numbers of species requires a comprehensive sampling effort, making it impractical and expensive. This

  13. 77 FR 70456 - Receipt of Applications for Endangered Species Permits

    Science.gov (United States)

    2012-11-26

    ...: TE-13844A Applicant: Aquatic Resources Management, Lexington, Kentucky. Applicant requests amendment... fish species, twelve (12) fresh-water mussel species, one (1) snake species, one (1) insect species and...

  14. ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

    Science.gov (United States)

    Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

  15. Biodiversity hotspots house most undiscovered plant species.

    Science.gov (United States)

    Joppa, Lucas N; Roberts, David L; Myers, Norman; Pimm, Stuart L

    2011-08-09

    For most organisms, the number of described species considerably underestimates how many exist. This is itself a problem and causes secondary complications given present high rates of species extinction. Known numbers of flowering plants form the basis of biodiversity "hotspots"--places where high levels of endemism and habitat loss coincide to produce high extinction rates. How different would conservation priorities be if the catalog were complete? Approximately 15% more species of flowering plant are likely still undiscovered. They are almost certainly rare, and depending on where they live, suffer high risks of extinction from habitat loss and global climate disruption. By using a model that incorporates taxonomic effort over time, regions predicted to contain large numbers of undiscovered species are already conservation priorities. Our results leave global conservation priorities more or less intact, but suggest considerably higher levels of species imperilment than previously acknowledged.

  16. New species in Aspergillus section Terrei

    DEFF Research Database (Denmark)

    Samson, R. A.; Peterson, S. W.; Frisvad, Jens Christian

    2011-01-01

    . clade including the type isolate of A. niveus (CBS 115.27) constitutes a lineage closely related to A. carneus. Fennellia nivea, the hypothesized teleomorph is not related to this clade. Aspergillus allahabadii, A. niveus var. indicus, and two species originally placed in section Versicolores, A......Section Terrei of Aspergillus was studied using a polyphasic approach including sequence analysis of parts of the beta-tubulin and calmodulin genes and the ITS region, macro- and micromorphological analyses and examination of extrolite profiles to describe three new species in this section. Based....... floccosus, A. terreus var. africanus, A. terreus var. aureus, while Aspergillus hortai is recognised at species level. Aspergillus terreus NRRL 4017 is described as the new species A. pseudoterreus. Also included in section Terrei are some species formerly placed in sections Flavipedes and Versicolores. A...

  17. Actinomyces Species Isolated from Breast Infections

    Science.gov (United States)

    Loh, S. F.; Morris, T.; Hughes, H.; Dixon, J. M.

    2015-01-01

    Actinomycosis is a chronic infection caused by Actinomyces species characterized by abscess formation, tissue fibrosis, and draining sinuses. The spectrum of infections caused by Actinomyces species ranges from classical invasive actinomycosis to a less invasive form of superficial skin and soft tissue infection. We present a review detailing all Actinomyces species isolated from breast infections in NHS Lothian between 2005 and 2013, Actinomyces species isolated from breast infections referred to the United Kingdom Anaerobe Reference Unit between 1988 and 2014, and cases describing Actinomyces breast infections published in the medical literature since 1994. Actinomyces species are fastidious organisms which can be difficult to identify and are likely to be underascertained as a cause of breast infections. Due to improved diagnostic methods, they are increasingly associated with chronic, recurrent breast infections and may play a more significant role in these infections than has previously been appreciated. PMID:26224846

  18. Region effects influence local tree species diversity.

    Science.gov (United States)

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

  19. The Porphyra species of Helgoland (Bangiales, Rhodophyta)

    Science.gov (United States)

    Kornmann, P.; Sahling, P.-H.

    1991-03-01

    This revision of seven Porphyra species of Helgoland was based on a study of the structure of their fertile thalli and the behaviour of their spores. Regarding the reproductive organization the species may be arranged in two groups. P. leucosticta and P. purpureo-violacea are obligate monoecious species. Asexual thalli have never been observed in the field. The other five species are generally dioecious. Isomorphic sexual thalli and asexually propagating ones are mixed in uniform populations. Carpospores originating from sexual fusion develop into the diploid Conchocelis phase. Sporangia of asexual plants, though homologous in formation, produce spores of different kinds: aplanospores that give rise to the vegetative thallus directly (in P. umbilicalis, P. insolita n. sp. and P. ochotensis) and spores that develop into haploid Conchocelis (in P. laciniata and in P. linearis). P. laciniata — formerly considered synonymous with P. purpurea — is an independent species.

  20. Effects of species' characteristics on nongovernmental organizations' attitudes toward species conservation policy

    NARCIS (Netherlands)

    Knegtering, E; Hendrickx, L.C W P; van der Windt, H.J.; Schoot Uiterkamp, A.J.M.

    The authors examined the willingness of nongovernmental organizations (NGOs) to support public species conservation measures as a function of species characteristics, NGOs' interests, and interests harmed by the measures. In an experiment, 39 policy makers from nature conservation, mobility and

  1. ConSpeciFix: Classifying prokaryotic species based on gene flow.

    Science.gov (United States)

    Bobay, Louis-Marie; Ellis, Brian Shin-Hua; Ochman, Howard

    2018-05-16

    Classification of prokaryotic species is usually based on sequence similarity thresholds, which are easy to apply but lack a biologically-relevant foundation. Here, we present ConSpeciFix, a program that classifies prokaryotes into species using criteria set forth by the Biological Species Concept, thereby unifying species definition in all domains of life. ConSpeciFix's webserver is freely available at www.conspecifix.com. The local version of the program can be freely downloaded from https://github.com/Bobay-Ochman/ConSpeciFix. ConSpeciFix is written in Python 2.7 and requires the following dependencies: Usearch, MCL, MAFFT and RAxML. ljbobay@uncg.edu.

  2. Genetic sorting of subordinate species in grassland modulated by intraspecific variation in dominant species.

    Directory of Open Access Journals (Sweden)

    Danny J Gustafson

    Full Text Available Genetic variation in a single species can have predictable and heritable effects on associated communities and ecosystem processes, however little is known about how genetic variation of a dominant species affects plant community assembly. We characterized the genetic structure of a dominant grass (Sorghastrum nutans and two subordinate species (Chamaecrista fasciculata, Silphium integrifolium, during the third growing season in grassland communities established with genetically distinct (cultivated varieties or local ecotypes seed sources of the dominant grasses. There were genetic differences between subordinate species growing in the cultivar versus local ecotype communities, indicating that intraspecific genetic variation in the dominant grasses affected the genetic composition of subordinate species during community assembly. A positive association between genetic diversity of S. nutans, C. fasciculata, and S. integrifolium and species diversity established the role of an intraspecific biotic filter during community assembly. Our results show that intraspecific variation in dominant species can significantly modulate the genetic composition of subordinate species.

  3. New species of Moenkhausia Eigenmann, 1903 (Characiformes: Characidae with comments on the Moenkhausia oligolepis species complex

    Directory of Open Access Journals (Sweden)

    Ricardo C. Benine

    Full Text Available A new species of Moenkhausia is described from tributaries of the rio Paraguay, Brazil. The new species is diagnosed from congeners by characters related to body coloration, the number of lateral line scales, the degree of poring of the lateral line, and number of scales rows above and below the lateral line. Molecular analyses using partial sequences of the mitochondrial gene Cytochrome Oxidase I from specimens of the new species and specimens belonging to morphologically similar species demonstrated that the new species is easily differentiated by their high genetic distance and by their position in the phylogenetic hypothesis obtained through the Maximum Parsimony methodology. The analyses of three samples of M. oligolepis also revealed that they have high genetic distances and belong to different monophyletic groups suggesting that this species corresponds to a species complex rather than a single species.

  4. 75 FR 38069 - Injurious Wildlife Species; Listing the Boa Constrictor, Four Python Species, and Four Anaconda...

    Science.gov (United States)

    2010-07-01

    ... Python Species, and Four Anaconda Species as Injurious Reptiles AGENCY: Fish and Wildlife Service... regulations to add Indian python (Python molurus, including Burmese python Python molurus bivittatus), reticulated python (Broghammerus reticulatus or Python reticulatus), Northern African python (Python sebae...

  5. Spatial Complementarity and the Coexistence of Species

    Science.gov (United States)

    Velázquez, Jorge; Garrahan, Juan P.; Eichhorn, Markus P.

    2014-01-01

    Coexistence of apparently similar species remains an enduring paradox in ecology. Spatial structure has been predicted to enable coexistence even when population-level models predict competitive exclusion if it causes each species to limit its own population more than that of its competitor. Nevertheless, existing hypotheses conflict with regard to whether clustering favours or precludes coexistence. The spatial segregation hypothesis predicts that in clustered populations the frequency of intra-specific interactions will be increased, causing each species to be self-limiting. Alternatively, individuals of the same species might compete over greater distances, known as heteromyopia, breaking down clusters and opening space for a second species to invade. In this study we create an individual-based model in homogeneous two-dimensional space for two putative sessile species differing only in their demographic rates and the range and strength of their competitive interactions. We fully characterise the parameter space within which coexistence occurs beyond population-level predictions, thereby revealing a region of coexistence generated by a previously-unrecognised process which we term the triadic mechanism. Here coexistence occurs due to the ability of a second generation of offspring of the rarer species to escape competition from their ancestors. We diagnose the conditions under which each of three spatial coexistence mechanisms operates and their characteristic spatial signatures. Deriving insights from a novel metric — ecological pressure — we demonstrate that coexistence is not solely determined by features of the numerically-dominant species. This results in a common framework for predicting, given any pair of species and knowledge of the relevant parameters, whether they will coexist, the mechanism by which they will do so, and the resultant spatial pattern of the community. Spatial coexistence arises from complementary combinations of traits in each

  6. Neosilba (Tephritoidea: Lonchaeidae) species reared from coffee in Brazil, with description of a new species

    Energy Technology Data Exchange (ETDEWEB)

    Striki, Pedro Carlos; Prado, Angelo Pires do, E-mail: apprado@unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Biologia. Dept. de Parasitologia

    2006-07-01

    Neosilba species are believed to be secondary invaders of fruit, so, little attention has been paid to its presence in coffee fruits. In this article we present a key to Neosilba species present in coffee fruits and describe a new species that is considered a primary invader. We hope this will help researchers working with coffee fruits to better quantify the economic importance of Neosilba species associated with coffee fruits. (author)

  7. Neosilba (Tephritoidea: Lonchaeidae) species reared from coffee in Brazil, with description of a new species

    International Nuclear Information System (INIS)

    Striki, Pedro Carlos; Prado, Angelo Pires do

    2006-01-01

    Neosilba species are believed to be secondary invaders of fruit, so, little attention has been paid to its presence in coffee fruits. In this article we present a key to Neosilba species present in coffee fruits and describe a new species that is considered a primary invader. We hope this will help researchers working with coffee fruits to better quantify the economic importance of Neosilba species associated with coffee fruits. (author)

  8. Two new species of nocturnal bees of the genus Megalopta (Hymenoptera: Halictidae) with keys to species

    OpenAIRE

    Gonzalez, Victor H; Griswold, Terry; Ayala, Ricardo

    2010-01-01

    Megalopta Smith, 1853, is a Neotropical genus of nocturnal or crepuscular bees. Two subgenera are recognized with most of its nearly 30 species placed in the nominate subgenus. Species of Megalopta s. str. are more commonly collected than species of Noctoraptor Engel et al. 1997, all presumably parasites of Megalopta s. str. Two new species of Megalopta are described here: M. (Megalopta) tetewana, n. sp., from Mexico and M. (Noctoraptor) huaoranii, n. sp., from Ecuador. Identification keys to...

  9. Dna c-values of 20 invasive alien species and 3 native species in south china

    OpenAIRE

    Gong Ni; Wang Yu-Tao; Björn Lars Olof; Li Shao-Shan

    2014-01-01

    Cultivated fields and forests in South China are experiencing serious damage due to invasive alien plants. We investigated the relation between DNA C-values and invasiveness. The DNA C-values of 23 species ranged from 0.39 pg to 3.37 pg. Herbs, perennials and native species had higher mean DNA C-values than shrubs, annuals and invasive alien species. DNA C-values decreased with increasing invasiveness. Paederia scandens, a harmful native species, has the lo...

  10. Invading species in the Eel River, California: Successes, failures, and relationships with resident species

    Science.gov (United States)

    Brown, L.R.; Moyle, P.B.

    1997-01-01

    We examined invasions of non-native fishes into the Eel River, California. At least 16 species of fish have been introduced into the drainage which originally supported 12-14 fish species. Our study was prompted by the unauthorized introduction in 1979 of Sacramento squawfish, Ptychocheilus grandis, a large predatory cyprinid. From 1986 to 1990, we conducted growth and diet studies of squaw fish, conducted intensive surveys of the distribution and habitat associations of both native and introduced species, and examined the nature of species-habitat and interspecies relationships. We found no evidence for increased growth or expanded feeding habits, compared to native populations, of Sacramento squawfish as they invaded the Eel River drainage. Ten of the introduced species were well established, with four species limited to a reservoir and six species established in streams. The success or failure of introductions of stream species appeared to be a function of the ability of a species to survive the fluctuating, highly seasonal, flow regime. The present mixture of native and exotic species has not formed stable fish assemblages but it seems likely that four habitat-associated assemblages will develop. The overall effect of the successful species introductions has been to assemble a group of species, with some exceptions, that are native to and occur together in many California streams. The assemblages now forming are similar to those found in other California streams. The assemblage characterized by squawfish and suckers is likely to be resistant to invasion, in the absence of human caused habitat modifications.

  11. Rare species contribute disproportionately to the functional structure of species assemblages.

    Science.gov (United States)

    Leitão, Rafael P; Zuanon, Jansen; Villéger, Sébastien; Williams, Stephen E; Baraloto, Christopher; Fortunel, Claire; Mendonça, Fernando P; Mouillot, David

    2016-04-13

    There is broad consensus that the diversity of functional traits within species assemblages drives several ecological processes. It is also widely recognized that rare species are the first to become extinct following human-induced disturbances. Surprisingly, however, the functional importance of rare species is still poorly understood, particularly in tropical species-rich assemblages where the majority of species are rare, and the rate of species extinction can be high. Here, we investigated the consequences of local and regional extinctions on the functional structure of species assemblages. We used three extensive datasets (stream fish from the Brazilian Amazon, rainforest trees from French Guiana, and birds from the Australian Wet Tropics) and built an integrative measure of species rarity versus commonness, combining local abundance, geographical range, and habitat breadth. Using different scenarios of species loss, we found a disproportionate impact of rare species extinction for the three groups, with significant reductions in levels of functional richness, specialization, and originality of assemblages, which may severely undermine the integrity of ecological processes. The whole breadth of functional abilities within species assemblages, which is disproportionately supported by rare species, is certainly critical in maintaining ecosystems particularly under the ongoing rapid environmental transitions. © 2016 The Author(s).

  12. Protectiveness of Species Sensitivity Distribution Hazard Concentrations for Acute Toxicity Used in Endangered Species Risk Assessment

    Science.gov (United States)

    A primary objective of threatened and endangered species conservation is to ensure that chemical contaminants and other stressors do not adversely affect listed species. Assessments of the ecological risks of chemical exposures to listed species often rely on the use of surrogate...

  13. Tree structural and species diversities in Okwangwo Forest, Cross ...

    African Journals Online (AJOL)

    Tree species were grouped into abundance classes. A total of 125 tree species belonging to 36 families and 96 genera were recorded in the area with Margaleffs index of species richness of 2.2754. Most (99) of the tree species encountered were threatened/endangered, 23 species were rare with only 3 tree species ...

  14. Estimating tree species richness from forest inventory plot data

    Science.gov (United States)

    Ronald E. McRoberts; Dacia M. Meneguzzo

    2007-01-01

    Montreal Process Criterion 1, Conservation of Biological Diversity, expresses species diversity in terms of number of forest dependent species. Species richness, defined as the total number of species present, is a common metric for analyzing species diversity. A crucial difficulty in estimating species richness from sample data obtained from sources such as inventory...

  15. Identifying ambassador species for conservation marketing

    Directory of Open Access Journals (Sweden)

    E.A. Macdonald

    2017-10-01

    Full Text Available Conservation relies heavily on external funding, much of it from a supportive public. Therefore it is important to know which species are most likely to catalyse such funding. Whilst previous work has looked at the physical attributes that contribute to a species' appeal, no previous studies have tried to examine the extent to which a species' sympatriots might contribute to it's potential as flagship for wider conservation. Therefore, here we estimate ‘flexibility’ and ‘appeal’ scores for all terrestrial mammals (n = 4320 and identify which of these might serve as ambassadors (defined as both highly appealing and flexible. Relatively few mammals (between 240 and 331 emerged as ambassadors, with carnivores featuring heavily in this group (representing 5% of terrestrial mammals but 39% of ambassadors. ‘Top ambassadors’ were defined as those with both flexibility and appeal scores greater than 1 standard deviation above the mean. Less than a quarter of the 20 most endangered and evolutionary distinct species in this study were classed as ambassadors, highlighting the need for surrogate species to catalyse conservation effort in areas with such priority species. This is the first global analysis bringing together flexibility and appeal for all terrestrial mammals, and demonstrates an approach for determining how best to market species in order to achieve maximal conservation gain in a world with urgent conservation need but limited resources.

  16. Design and construction of "synthetic species".

    Directory of Open Access Journals (Sweden)

    Eduardo Moreno

    Full Text Available Synthetic biology is an area of biological research that combines science and engineering. Here, I merge the principles of synthetic biology and regulatory evolution to create a new species with a minimal set of known elements. Using preexisting transgenes and recessive mutations of Drosophila melanogaster, a transgenic population arises with small eyes and a different venation pattern that fulfils the criteria of a new species according to Mayr's Biological Species Concept. The population described here is the first transgenic organism that cannot hybridize with the original wild type population but remains fertile when crossed with other identical transgenic animals. I therefore propose the term "synthetic species" to distinguish it from "natural species", not only because it has been created by genetic manipulation, but also because it may never be able to survive outside the laboratory environment. The use of genetic engineering to design artificial species barriers could help us understand natural speciation and may have practical applications. For instance, the transition from transgenic organisms towards synthetic species could constitute a safety mechanism to avoid the hybridization of genetically modified animals with wild type populations, preserving biodiversity.

  17. Fusarium Species and Their Associated Mycotoxins.

    Science.gov (United States)

    Munkvold, Gary P

    2017-01-01

    The genus Fusarium includes numerous toxigenic species that are pathogenic to plants or humans, and are able to colonize a wide range of environments on earth. The genus comprises around 70 well-known species, identified by using a polyphasic approach, and as many as 300 putative species, according to phylogenetic species concepts; many putative species do not yet have formal names. Fusarium is one of the most economically important fungal genera because of yield loss due to plant pathogenic activity; mycotoxin contamination of food and feed products which often render them unaccep for marketing; and health impacts to humans and livestock, due to consumption of mycotoxins. Among the most important mycotoxins produced by species of Fusarium are the trichothecenes and the fumonisins. Fumonisins cause fatal livestock diseases and are considered potentially carcinogenic mycotoxins for humans, while trichothecenes are potent inhibitors of protein synthesis. This chapter summarizes the main aspects of morphology, pathology, and toxigenicity of the main Fusarium species that colonize different agricultural crops and environments worldwide, and cause mycotoxin contamination of food and feed.

  18. Species coexistence in a changing world.

    Science.gov (United States)

    Valladares, Fernando; Bastias, Cristina C; Godoy, Oscar; Granda, Elena; Escudero, Adrián

    2015-01-01

    The consequences of global change for the maintenance of species diversity will depend on the sum of each species responses to the environment and on the interactions among them. A wide ecological literature supports that these species-specific responses can arise from factors related to life strategies, evolutionary history and intraspecific variation, and also from environmental variation in space and time. In the light of recent advances from coexistence theory combined with mechanistic explanations of diversity maintenance, we discuss how global change drivers can influence species coexistence. We revise the importance of both competition and facilitation for understanding coexistence in different ecosystems, address the influence of phylogenetic relatedness, functional traits, phenotypic plasticity and intraspecific variability, and discuss lessons learnt from invasion ecology. While most previous studies have focused their efforts on disentangling the mechanisms that maintain the biological diversity in species-rich ecosystems such as tropical forests, grasslands and coral reefs, we argue that much can be learnt from pauci-specific communities where functional variability within each species, together with demographic and stochastic processes becomes key to understand species interactions and eventually community responses to global change.

  19. Phylogenetic and Phylogenomic Definition of Rhizopus Species

    Directory of Open Access Journals (Sweden)

    Andrii P. Gryganskyi

    2018-06-01

    Full Text Available Phylogenomic approaches have the potential to improve confidence about the inter-relationships of species in the order Mucorales within the fungal tree of life. Rhizopus species are especially important as plant and animal pathogens and bioindustrial fermenters for food and metabolite production. A dataset of 192 orthologous genes was used to construct a phylogenetic tree of 21 Rhizopus strains, classified into four species isolated from habitats of industrial, medical and environmental importance. The phylogeny indicates that the genus Rhizopus consists of three major clades, with R. microsporus as the basal species and the sister lineage to R. stolonifer and two closely related species R. arrhizus and R. delemar. A comparative analysis of the mating type locus across Rhizopus reveals that its structure is flexible even between different species in the same genus, but shows similarities between Rhizopus and other mucoralean fungi. The topology of single-gene phylogenies built for two genes involved in mating is similar to the phylogenomic tree. Comparison of the total length of the genome assemblies showed that genome size varies by as much as threefold within a species and is driven by changes in transposable element copy numbers and genome duplications.

  20. Recent advances in probabilistic species pool delineations

    Directory of Open Access Journals (Sweden)

    Dirk Nikolaus Karger

    2016-07-01

    Full Text Available A species pool is the set of species that could potentially colonize and establish within a community. It has been a commonly used concept in biogeography since the early days of MacArthur and Wilson’s work on Island Biogeography. Despite their simple and appealing definition, an operational application of species pools is bundled with a multitude of problems, which have often resulted in arbitrary decisions and workarounds when defining species pools. Two recently published papers address the operational problems of species pool delineations, and show ways of delineating them in a probabilistic fashion. In both papers, species pools were delineated using a process-based, mechanistical approach, which opens the door for a multitude of new applications in biogeography. Such applications include detecting the hidden signature of biotic interactions, disentangling the geographical structure of community assembly processes, and incorporating a temporal extent into species pools. Although similar in their conclusions, both ‘probabilistic approaches’ differ in their implementation and definitions. Here I give a brief overview of the differences and similarities of both approaches, and identify the challenges and advantages in their application.

  1. Pushing the pace of tree species migration.

    Directory of Open Access Journals (Sweden)

    Eli D Lazarus

    Full Text Available Plants and animals have responded to past climate changes by migrating with habitable environments, sometimes shifting the boundaries of their geographic ranges by tens of kilometers per year or more. Species migrating in response to present climate conditions, however, must contend with landscapes fragmented by anthropogenic disturbance. We consider this problem in the context of wind-dispersed tree species. Mechanisms of long-distance seed dispersal make these species capable of rapid migration rates. Models of species-front migration suggest that even tree species with the capacity for long-distance dispersal will be unable to keep pace with future spatial changes in temperature gradients, exclusive of habitat fragmentation effects. Here we present a numerical model that captures the salient dynamics of migration by long-distance dispersal for a generic tree species. We then use the model to explore the possible effects of assisted colonization within a fragmented landscape under a simulated tree-planting scheme. Our results suggest that an assisted-colonization program could accelerate species-front migration rates enough to match the speed of climate change, but such a program would involve an environmental-sustainability intervention at a massive scale.

  2. Cryptic species as a window into the paradigm shift of the species concept.

    Science.gov (United States)

    Fišer, Cene; Robinson, Christopher T; Malard, Florian

    2018-02-01

    The species concept is the cornerstone of biodiversity science, and any paradigm shift in the delimitation of species affects many research fields. Many biologists now are embracing a new "species" paradigm as separately evolving populations using different delimitation criteria. Individual criteria can emerge during different periods of speciation; some may never evolve. As such, a paradigm shift in the species concept relates to this inherent heterogeneity in the speciation process and species category-which is fundamentally overlooked in biodiversity research. Cryptic species fall within this paradigm shift: they are continuously being reported from diverse animal phyla but are poorly considered in current tests of ecological and evolutionary theory. The aim of this review is to integrate cryptic species in biodiversity science. In the first section, we address that the absence of morphological diversification is an evolutionary phenomenon, a "process" counterpart to the long-studied mechanisms of morphological diversification. In the next section regarding taxonomy, we show that molecular delimitation of cryptic species is heavily biased towards distance-based methods. We also stress the importance of formally naming of cryptic species for better integration into research fields that use species as units of analysis. Finally, we show that incorporating cryptic species leads to novel insights regarding biodiversity patterns and processes, including large-scale biodiversity assessments, geographic variation in species distribution and species coexistence. It is time for incorporating multicriteria species approaches aiming to understand speciation across space and taxa, thus allowing integration into biodiversity conservation while accommodating for species uncertainty. © 2018 John Wiley & Sons Ltd.

  3. Review: Allee effects in social species.

    Science.gov (United States)

    Angulo, Elena; Luque, Gloria M; Gregory, Stephen D; Wenzel, John W; Bessa-Gomes, Carmen; Berec, Ludek; Courchamp, Franck

    2018-01-01

    Allee effects have important implications for many aspects of basic and applied ecology. The benefits of aggregation of conspecific individuals are central to Allee effects, which have led to the widely held assumption that social species are more prone to Allee effects. Robust evidence for this assumption, however, remains rare. Furthermore, previous research on Allee effects has failed to adequately address the consequences of the different levels of organisation within social species' populations. Here, we review available evidence of Allee effects and model the role of demographic and behavioural factors that may combine to dampen or strengthen Allee effects in social species. We use examples across various species with contrasting social structure, including carnivores, bats, primates and eusocial insects. Building on this, we provide a conceptual framework that allows for the integration of different Allee effects in social species. Social species are characterised by nested levels of organisation. The benefits of cooperation, measured by mean individual fitness, can be observed at both the population and group levels, giving rise to "population level" and "group level" Allee effects respectively. We also speculate on the possibility of a third level, reporting per capita benefits for different individuals within a group (e.g. castes in social insects). We show that group size heterogeneity and intergroup interactions affect the strength of population-level demographic Allee effects. Populations with higher group size heterogeneity and in which individual social groups cooperate demonstrate the weakest Allee effects and may thus provide an explanation for why extinctions due to Allee effects are rare in social species. More adequately accounting for Allee effects in social species will improve our understanding of the ecological and evolutionary implications of cooperation in social species. © 2017 The Authors. Journal of Animal Ecology © 2017 British

  4. Economics of Harmful Invasive Species: A Review

    Directory of Open Access Journals (Sweden)

    George Marbuah

    2014-07-01

    Full Text Available The purpose of this study is to review theoretical and empirical findings in economics with respect to the challenging question of how to manage invasive species. The review revealed a relatively large body of literature on the assessment of damage costs of invasive species; single species and groups of species at different geographical scales. However, the estimated damage costs show large variation, from less than 1 million USD to costs corresponding to 12% of gross domestic product, depending on the methods employed, geographical scale, and scope with respect to inclusion of different species. Decisions regarding optimal management strategies, when to act in the invasion chain and which policy to choose, have received much less attention in earlier years, but have been subject to increasing research during the last decade. More difficult, but also more relevant policy issues have been raised, which concern the targeting in time and space of strategies under conditions of uncertainty. In particular, the weighting of costs and benefits from early detection and mitigation against the uncertain avoidance of damage with later control, when the precision in targeting species is typically greater is identified as a key challenge. The role of improved monitoring for detecting species and their spread and damage has been emphasized, but questions remain on how to achieve this in practice. This is in contrast to the relatively large body of literature on policies for mitigating dispersal by trade, which is regarded as one of the most important vectors for the spread of invasive species. On the other hand, the literature on how to mitigate established species, by control or adaptation, is much more scant. Studies evaluating causes for success or failure of policies against invasive in practice are in principal non-existing.

  5. An updated checklist of mosquito species (Diptera: Culicidae) from Madagascar

    Science.gov (United States)

    Tantely, Michaël Luciano; Le Goff, Gilbert; Boyer, Sébastien; Fontenille, Didier

    2016-01-01

    An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species). This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species), Aedes (35 species), Anopheles (26 species), Coquillettidia (3 species), Culex (at least 50 species), Eretmapodites (4 species), Ficalbia (2 species), Hodgesia (at least one species), Lutzia (one species), Mansonia (2 species), Mimomyia (22 species), Orthopodomyia (8 species), Toxorhynchites (6 species), and Uranotaenia (73 species). Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%). Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27%) with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar. PMID:27101839

  6. An updated checklist of mosquito species (Diptera: Culicidae from Madagascar

    Directory of Open Access Journals (Sweden)

    Tantely Michaël Luciano

    2016-01-01

    Full Text Available An updated checklist of 235 mosquito species from Madagascar is presented. The number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species. This annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. The 235 species belong to 14 genera: Aedeomyia (3 species, Aedes (35 species, Anopheles (26 species, Coquillettidia (3 species, Culex (at least 50 species, Eretmapodites (4 species, Ficalbia (2 species, Hodgesia (at least one species, Lutzia (one species, Mansonia (2 species, Mimomyia (22 species, Orthopodomyia (8 species, Toxorhynchites (6 species, and Uranotaenia (73 species. Due to non-deciphered species complexes, several species remain undescribed. The main remarkable characteristic of Malagasy mosquito fauna is the high biodiversity with 138 endemic species (59%. Presence and abundance of species, and their association, in a given location could be a bio-indicator of environmental particularities such as urban, rural, forested, deforested, and mountainous habitats. Finally, taking into account that Malagasy culicidian fauna includes 64 species (27% with a known medical or veterinary interest in the world, knowledge of their biology and host preference summarized in this paper improves understanding of their involvement in pathogen transmission in Madagascar.

  7. Cross-species amplification of 105 Lolium perenne SSR loci in 23 species within the Poaceae

    DEFF Research Database (Denmark)

    Jensen, Louise Bach; Holm, Preben Bach; Lübberstedt, Thomas

    2007-01-01

    Amplification of 105 Lolium perenne SSR markers was studied in 23 grass species representing seven tribes from three subfamilies of Poaceae. Twelve of the SSR markers are published for the first time. Between 2% and 96% of the SSR markers could be amplified within a given species. A subset of eight...... SSR markers was evaluated for polymorphism across nine of the 23 grass species. Four to seven of the markers were polymorphic within each species, with an average detection of 2.4 alleles per species....

  8. Dna c-values of 20 invasive alien species and 3 native species in south china

    Directory of Open Access Journals (Sweden)

    Gong Ni

    2014-01-01

    Full Text Available Cultivated fields and forests in South China are experiencing serious damage due to invasive alien plants. We investigated the relation between DNA C-values and invasiveness. The DNA C-values of 23 species ranged from 0.39 pg to 3.37 pg. Herbs, perennials and native species had higher mean DNA C-values than shrubs, annuals and invasive alien species. DNA C-values decreased with increasing invasiveness. Paederia scandens, a harmful native species, has the lowest DNA C-value among the perennials, indicating that native species with low nuclear content may also possess an invasive potential.

  9. Metabolite production by species of Stemphylium

    DEFF Research Database (Denmark)

    Olsen, Kresten Jon Kromphardt; Rossman, Amy; Andersen, Birgitte

    2018-01-01

    metabolites were found to be important for distinguishing species, while some unknown metabolites were also found to have important roles in distinguishing species of Stemphylium. This study is the first of its kind to investigate the chemical potential of Stemphylium across the whole genus.......Morphology and phylogeny has been used to distinguish members of the plant pathogenic fungal genus Stemphylium. A third method for distinguishing species is by chemotaxonomy. The main goal of the present study was to investigate the chemical potential of Stemphylium via HPLC-UV-MS analysis, while...

  10. Reservoirs of Non-baumannii Acinetobacter Species

    Science.gov (United States)

    Al Atrouni, Ahmad; Joly-Guillou, Marie-Laure; Hamze, Monzer; Kempf, Marie

    2016-01-01

    Acinetobacter spp. are ubiquitous gram negative and non-fermenting coccobacilli that have the ability to occupy several ecological niches including environment, animals and human. Among the different species, Acinetobacter baumannii has evolved as global pathogen causing wide range of infection. Since the implementation of molecular techniques, the habitat and the role of non-baumannii Acinetobacter in human infection have been elucidated. In addition, several new species have been described. In the present review, we summarize the recent data about the natural reservoir of non-baumannii Acinetobacter including the novel species that have been described for the first time from environmental sources and reported during the last years. PMID:26870013

  11. Tree Species Identity Shapes Earthworm Communities

    DEFF Research Database (Denmark)

    Schelfhout, Stephanie; Mertens, Jan; Verheyen, Kris

    2017-01-01

    Earthworms are key organisms in forest ecosystems because they incorporate organic material into the soil and affect the activity of other soil organisms. Here, we investigated how tree species affect earthworm communities via litter and soil characteristics. In a 36-year old common garden...... of soil and foliar litter, and determined the forest floor turnover rate and the density and biomass of the earthworm species occurring in the stands. Tree species significantly affected earthworm communities via leaf litter and/or soil characteristics. Anecic earthworms were abundant under Fraxinus, Acer...

  12. Fort Collins Science Center: Invasive Species Science

    Science.gov (United States)

    Stohlgren, Tom

    2004-01-01

    Invasive, non-native species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like "biological wildfires," they can quickly spread, and they affect nearly all terrestrial and aquatic ecosystems. Invasive species have become the greatest environmental challenge of the 21st century in terms of economic, environmental, and human health costs, with an estimated impact in the U.S. of over $138 billion per year. Managers of Department of the Interior and other public and private lands and waters rank invasive species as their top resource management problem.

  13. Fatty acid composition of forage herb species

    DEFF Research Database (Denmark)

    Warner, D.; Jensen, Søren Krogh; Cone, J.W.

    2010-01-01

    The use of alternative forage species in grasslands for intensive livestock production is receiving renewed attention. Data on fatty acid composition of herbs are scarce, so four herbs (Plantago lanceolata, Achillea millefolium, Cichorium intybus, Pastinaca sativa) and one grass species (timothy......, Phleum pratense) were sown in a cutting trial. The chemical composition and concentration of fatty acids (FA) of individual species were determined during the growing season. Concentrations of crude protein and FA were generally higher in the herbs than in timothy. C. intybus had the highest nutritive...

  14. Species Diversity Enhances Predator Growth Rates

    International Nuclear Information System (INIS)

    Olson, M.H.; Jacobs, R.P.; O'Donnell, E.B.

    2007-01-01

    Predators can be important top-down regulators of community structure and are known to have both positive and negative effects on species diversity. However, little is known about the reciprocal effects of species diversity on predators. Across a set of 80 lakes in Connecticut, USA, we found a strong positive correlation between prey species diversity (using the Shannon-Weiner Diversity Index) and growth rates of largemouth bass (Micropterus salmoides). This correlation was strongest for small predators and decreased with body size. Although the underlying mechanisms are not known, the correlation is not driven by total fish abundance, predator abundance, or productivity.

  15. Predictions For New, Exotic Actinide Species

    International Nuclear Information System (INIS)

    Pyykko, P.

    2002-01-01

    The approach. New, simple chemical species can be predicted by studying isoelectronic series using ab initio quantum chemistry. We currently use in most cases relativistic pseudopotentials and handle the electron correlation using density functional theory (DFT) or wave-function-based methods, from MP2 to CCSD(T). Typical codes are Gaussian 98, Turbomole or MolCas. For full four-component Dirac-Fock calculations, the DREAMS code of K. G. Dyall has been utilized. For mapping out the possible new species, complete maps of all possibilities are made, whenever possible, and the new species typically occur along the coast-line of the 'island of stability' of already known species

  16. antimicrobial susceptibility pattern of Salmonella species

    African Journals Online (AJOL)

    user

    GLOBAL JOURNAL OF COMMUNITY MEDICINE VOL. 2 NO. 1 & 2 2009: 5 - ... This study is a review of the contemporary antimicrobial susceptibility pattern of. Salmonella species. ... south-east Asia, parts of Latin America, the. Caribbean, and ...

  17. Metabolomic analysis of three Mollicute species.

    Directory of Open Access Journals (Sweden)

    Anna A Vanyushkina

    Full Text Available We present a systematic study of three bacterial species that belong to the class Mollicutes, the smallest and simplest bacteria, Spiroplasma melliferum, Mycoplasma gallisepticum, and Acholeplasma laidlawii. To understand the difference in the basic principles of metabolism regulation and adaptation to environmental conditions in the three species, we analyzed the metabolome of these bacteria. Metabolic pathways were reconstructed using the proteogenomic annotation data provided by our lab. The results of metabolome, proteome and genome profiling suggest a fundamental difference in the adaptation of the three closely related Mollicute species to stress conditions. As the transaldolase is not annotated in Mollicutes, we propose variants of the pentose phosphate pathway catalyzed by annotated enzymes for three species. For metabolite detection we employed high performance liquid chromatography coupled with mass spectrometry. We used liquid chromatography method - hydrophilic interaction chromatography with silica column - as it effectively separates highly polar cellular metabolites prior to their detection by mass spectrometer.

  18. Luminescence properties of uranyl-acetate species

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, Hannes; Moll, Henry [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

    2017-06-01

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) was applied to characterize uranium(VI)- acetate species based on their luminescence properties. In contrast to previous interpretations, no indications were detected for the existence of the 1: 3 complex.

  19. Influence of estuaries on shelf foraminiferal species

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Dabhol-bhatkal stretch of the west coast of India is marked by a number of estuaries. Cavarotalia annectens is selected to monitor the influence of these estuaries on the inner shelf foraminiferal fauna. The percentage distribution of this species...

  20. CONSERVATION METHODS OF ENDANGERED SPECIES GUNDU ...

    African Journals Online (AJOL)

    user

    Department of Forestry, Akperan Orshi College of Agriculture Yandev, Gboko ... conservation measure, an endangered species finally goes into extinction, that ... either for tourism, scientific studies/ .... economic, educational, scientific, cultural.

  1. New trends in species distribution modelling

    Science.gov (United States)

    Zimmermann, Niklaus E.; Edwards, Thomas C.; Graham, Catherine H.; Pearman, Peter B.; Svenning, Jens-Christian

    2010-01-01

    Species distribution modelling has its origin in the late 1970s when computing capacity was limited. Early work in the field concentrated mostly on the development of methods to model effectively the shape of a species' response to environmental gradients (Austin 1987, Austin et al. 1990). The methodology and its framework were summarized in reviews 10–15 yr ago (Franklin 1995, Guisan and Zimmermann 2000), and these syntheses are still widely used as reference landmarks in the current distribution modelling literature. However, enormous advancements have occurred over the last decade, with hundreds – if not thousands – of publications on species distribution model (SDM) methodologies and their application to a broad set of conservation, ecological and evolutionary questions. With this special issue, originating from the third of a set of specialized SDM workshops (2008 Riederalp) entitled 'The Utility of Species Distribution Models as Tools for Conservation Ecology', we reflect on current trends and the progress achieved over the last decade.

  2. Cooperation and the Endangered Species Act

    International Nuclear Information System (INIS)

    Palmer, S.C.

    1991-01-01

    Passage of the Endangered Species Act in 1973 set the stage for some of the nations most polemic environmental battles. One of these is in the Colorado River Basin which is home to four native and rare fish species. Acrimonious confrontation has characterized the consultations under the ESA regarding these fish species. In 1983, the U.S. Fish and Wildlife Service announced that no new water depletions such as for hydropower plants, from the Upper Colorado River Basin would be allowed. This created no small stir among basin states and water developers and a negotiated solution was sought. The result was the Recovery Implementation Program for Endangered Fish Species in the Upper Colorado River Basin. This paper reports that models of political negotiation indicate conceptually, that the Recovery Program with its decisions made by unanimity of consensus, its open process and sharing of information, its shared budget and users fees, is a vehicle of political compromise and cooperation

  3. Bioeconomic analysis supports the endangered species act.

    Science.gov (United States)

    Salau, Kehinde R; Fenichel, Eli P

    2015-10-01

    The United States Endangered Species Act (ESA) was enacted to protect and restore declining fish, wildlife, and plant populations. The ESA mandates endangered species protection irrespective of costs. This translates to the restriction of activities that harm endangered populations. We discuss criticisms of the ESA in the context of public land management and examine under what circumstance banning non-conservation activity on multiple use federal lands can be socially optimal. We develop a bioeconomic model to frame the species management problem under the ESA and identify scenarios where ESA-imposed regulations emerge as optimal strategies. Results suggest that banning harmful activities is a preferred strategy when valued endangered species are in decline or exposed to poor habitat quality. However, it is not optimal to sustain such a strategy in perpetuity. An optimal plan involves a switch to land-use practices characteristic of habitat conservation plans.

  4. The Drosophila bipectinata species complex: phylogenetic ...

    Indian Academy of Sciences (India)

    PARUL BANERJEE

    c Indian Academy of Sciences. RESEARCH ARTICLE. The Drosophila bipectinata species complex: phylogenetic relationship among different members based on chromosomal variations. PARUL BANERJEE and BASHISTH N. SINGH. ∗. Genetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi ...

  5. A cross-species alignment tool (CAT)

    DEFF Research Database (Denmark)

    Li, Heng; Guan, Liang; Liu, Tao

    2007-01-01

    BACKGROUND: The main two sorts of automatic gene annotation frameworks are ab initio and alignment-based, the latter splitting into two sub-groups. The first group is used for intra-species alignments, among which are successful ones with high specificity and speed. The other group contains more...... sensitive methods which are usually applied in aligning inter-species sequences. RESULTS: Here we present a new algorithm called CAT (for Cross-species Alignment Tool). It is designed to align mRNA sequences to mammalian-sized genomes. CAT is implemented using C scripts and is freely available on the web...... at http://xat.sourceforge.net/. CONCLUSIONS: Examined from different angles, CAT outperforms other extant alignment tools. Tested against all available mouse-human and zebrafish-human orthologs, we demonstrate that CAT combines the specificity and speed of the best intra-species algorithms, like BLAT...

  6. Marine linefish programme priority species list

    CSIR Research Space (South Africa)

    Wallace, JH

    1983-05-01

    Full Text Available in Durban in April 1982. For each species, information is presented on; distribution, angling status, preferred habitat, growth, reproduction, catch statistics and further research work required. The publication is intended to act as a working document...

  7. Germplasm characterization of three jabuticaba tree species

    Directory of Open Access Journals (Sweden)

    Moeses Andrigo Danner

    2011-09-01

    Full Text Available The purpose of this study was to characterize cultivated genotypes of three jabuticaba species (Plinia cauliflora, P. trunciflora, and P. jaboticaba. Phenology and fruit growth, as well as leaf, flower and fruit traits were evaluated. Variability in all traits was observed among genotypes of the three jabuticaba species. The trait peduncle size is indicated for differentiation of the three species under study. The leaf and fruit sizes of the genotypes P. trunciflora 3, P. trunciflora 4, P. trunciflora 5 and P. jaboticaba 1 differ from those described in the literature for these species, indicating the formation of ecotypes. Jabuticaba fruit skin contains high anthocyanin and flavonoid concentrations, with potential use in food and pharmaceutical industries.

  8. Density of Threatened and Endangered Species

    Data.gov (United States)

    California Natural Resource Agency — A compiled density of threatened and endangered species built around 2000m wide hexagonal cells. The dataset was created by generating a blank hex grid, intersecting...

  9. Invasive species unchecked by climate - response

    DEFF Research Database (Denmark)

    Burrows, Michael T.; Schoeman, David S.; Duarte, Carlos M.

    2012-01-01

    environments. This may be particularly true in the world's boreal oceans as melting sea ice facilitates new migratory passages between the Atlantic and Pacific Oceans. Moreover, as the ebb and flow of biodiversity intensifies under anthropogenic climate change, novel climates and communities of species......Hulme points out that observed rates of range expansion by invasive alien species are higher than the median speed of isotherm movement over the past 50 years, which in turn has outpaced the rates of climate-associated range changes of marine and terrestrial species. This is not surprising, given...... of climate-change-induced range shifts between native and alien species are meaningful only after the initial invasive spread has reached a stable range boundary. A focus on regions with high velocities of climate change, and on regions such as the tropics where novel thermal niches are being created, should...

  10. Osmoregulation in three species of Ambassidae (Osteichthyes ...

    African Journals Online (AJOL)

    1989-07-25

    Jul 25, 1989 ... the temperature tolerance ranges of the three species (Martin. 1988) suggest that ..... dependent on the period spent in freshwater (Holliday 1971;. Nordlie 1985). .... GILLES, R. 1975. Mechanisms of ion and osmoregulation.

  11. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia; Estrada, Alba; Font, Xavier; Matias, Miguel G.; Meireles, Catarina; Mendoza, Manuel; Honrado, Joao P.; Prasad, Hari D.; Vicente, Joana R.; Early, Regan

    2018-01-01

    spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. 'community structure') reflects assembly processes occurring at small scales

  12. Sensory quality criteria for five fish species

    DEFF Research Database (Denmark)

    Warm, Karin; Nielsen, Jette; Hyldig, Grethe

    2000-01-01

    Sensory profiling has been used to develop one sensory vocabulary for five fish species: cod (Gadus morhua), saithe (Pollachius virens), rainbow trout (Salmo gardineri), herring (Clupea harengus) and flounder (Platichthys flessus). A nine- member trained panel assessed 18 samples with variation i...... variation and by presenting references, panel discussions and interpreting plots from multivariate data analysis. The developed profile can be used as a sensory wheel for these species, and with minor changes it may be adapted to similar species......Sensory profiling has been used to develop one sensory vocabulary for five fish species: cod (Gadus morhua), saithe (Pollachius virens), rainbow trout (Salmo gardineri), herring (Clupea harengus) and flounder (Platichthys flessus). A nine- member trained panel assessed 18 samples with variation...

  13. On two new species of Siriella (Mysidacea)

    Digital Repository Service at National Institute of Oceanography (India)

    Panampunnayil, S.U.

    Descriptions of two new mysids, Siriella africana ap. nov. collected from Agulhas Bank and S. intermedia sp. nov. collected from Laccadives are given. The present paper contains observations on two species of mysidacea collected from the Indian...

  14. Quantifying Temporal Genomic Erosion in Endangered Species.

    Science.gov (United States)

    Díez-Del-Molino, David; Sánchez-Barreiro, Fatima; Barnes, Ian; Gilbert, M Thomas P; Dalén, Love

    2018-03-01

    Many species have undergone dramatic population size declines over the past centuries. Although stochastic genetic processes during and after such declines are thought to elevate the risk of extinction, comparative analyses of genomic data from several endangered species suggest little concordance between genome-wide diversity and current population sizes. This is likely because species-specific life-history traits and ancient bottlenecks overshadow the genetic effect of recent demographic declines. Therefore, we advocate that temporal sampling of genomic data provides a more accurate approach to quantify genetic threats in endangered species. Specifically, genomic data from predecline museum specimens will provide valuable baseline data that enable accurate estimation of recent decreases in genome-wide diversity, increases in inbreeding levels, and accumulation of deleterious genetic variation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Endangered Species Litigation and Associated Pesticide Limitations

    Science.gov (United States)

    EPA has been subject to several citizen suits. As a result we have conducted scientific assessments and made effects determinations for various pesticide products as related to specific species of concern.

  16. ESUSA: US endangered species distribution file

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, J.; Calef, C.E.

    1979-10-01

    This report describes a file containing distribution data on endangered species of the United States of Federal concern pursuant to the Endangered Species Act of 1973. Included for each species are (a) the common name, (b) the scientific name, (c) the family, (d) the group (mammal, bird, etc.), (e) Fish and Wildlife Service (FWS) listing and recovery priorities, (f) the Federal legal status, (g) the geographic distribution by counties or islands, (h) Federal Register citations and (i) the sources of the information on distribution of the species. Status types are endangered, threatened, proposed, formally under review, candidate, deleted, and rejected. Distribution is by Federal Information Processing Standard (FIPS) county code and is of four types: designated critical habitat, present range, potential range, and historic range.

  17. EXTRACTION AND ANTIOXIDANT ACTIVITIES OF TWO SPECIES ...

    African Journals Online (AJOL)

    2013-06-30

    Jun 30, 2013 ... Origanum vulgare were investigated and also the total phenolic and ... species majorana, and vulgare respectively; also the DPPH of essential oil of Origanum ... inflammatory, antimicrobial and antioxidant activities[10] .

  18. Clonal growth and plant species abundance.

    Science.gov (United States)

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-08-01

    Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf-height-seed) traits and by actual performance in the botanical garden. Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area - height - seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially underlying clonal growth effects on abundance. Garden

  19. The Endangered Species Act and Sound Science

    Science.gov (United States)

    2006-10-05

    population segment” under ESA? ! If a species is wide-ranging and begins, on its own, to reappear in an area it once occupied (as with a few wolves in... Yellowstone ), should these animals be regarded as a “resident population” for purposes of ESA? ! Should a formerly widely-distributed species (such as bald... wolves ), and is delisted as soon as possible (as with bald eagles and Florida panthers). Representatives of many scientific or environmental

  20. Invasive Species - A Threat to the Homeland?

    Science.gov (United States)

    2003-04-07

    species of weeds, diseases and organisms on both my farm and the surrounding woodlands. Some of these species include soybean cyst nematode, soybean aphid ...natural enemies in their new environment. Parasites, pathogens , or predators that would inhibit or limit their spread are few or non-existent. In...tested, and fielded to control the genetically modified organism. Serums would be less effective, and diagnosis of human pathogens could change and

  1. Isoprene emission from tropical tree species

    International Nuclear Information System (INIS)

    Padhy, P.K.; Varshney, C.K.

    2005-01-01

    Foliar emission of isoprene was measured in nine commonly growing tree species of Delhi, India. Dynamic flow enclosure technique was used and gas samples were collected onto Tenax-GC/Carboseive cartridges, which were then attached to the sample injection system in the gas chromatograph (GC). Eluting compounds were analysed using a flame ionisation detector (FID). Out of the nine tree species, isoprene emission was found in six species (Eucalyptus sp., Ficus benghalensis, Ficus religiosa, Mangifera indica, Melia azedarach, and Syzygium jambolanum), whereas, in the remaining three tree species (Alstonia scholaris, Azadirachta indica, and Cassia fistula) no isoprene emission was detected or the levels of emission were negligible or below the detection limit (BDL). Among six tree species, the highest hourly emission (10.2±6.8 μg g -1 leaf dry weight, average of five seasons) was observed in Ficus religiosa, while minimum emission was from Melia azedarach (2.2±4.9 μg g -1 leaf dry weight, average of five seasons). Isoprene emission (average of six species), over five seasons, was found to vary between 3.9 and 8.5 μg g -1 leaf dry weight during the rainy season. In addition, significant diurnal variation in isoprene emission was observed in each species. The preliminary estimate made in this study on the annual biogenic VOC emission from India may probably be the first of its kind from this part of the world. - Isoprene flux (diurnal and seasonal) from some tropical tree species was estimated and a regional comparison was made

  2. Isoprene emission from tropical tree species

    Energy Technology Data Exchange (ETDEWEB)

    Padhy, P.K. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)]. E-mail: padhypk2003@yahoo.com; Varshney, C.K. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)

    2005-05-01

    Foliar emission of isoprene was measured in nine commonly growing tree species of Delhi, India. Dynamic flow enclosure technique was used and gas samples were collected onto Tenax-GC/Carboseive cartridges, which were then attached to the sample injection system in the gas chromatograph (GC). Eluting compounds were analysed using a flame ionisation detector (FID). Out of the nine tree species, isoprene emission was found in six species (Eucalyptus sp., Ficus benghalensis, Ficus religiosa, Mangifera indica, Melia azedarach, and Syzygium jambolanum), whereas, in the remaining three tree species (Alstonia scholaris, Azadirachta indica, and Cassia fistula) no isoprene emission was detected or the levels of emission were negligible or below the detection limit (BDL). Among six tree species, the highest hourly emission (10.2{+-}6.8 {mu}g g{sup -1} leaf dry weight, average of five seasons) was observed in Ficus religiosa, while minimum emission was from Melia azedarach (2.2{+-}4.9 {mu}g g{sup -1} leaf dry weight, average of five seasons). Isoprene emission (average of six species), over five seasons, was found to vary between 3.9 and 8.5 {mu}g g{sup -1} leaf dry weight during the rainy season. In addition, significant diurnal variation in isoprene emission was observed in each species. The preliminary estimate made in this study on the annual biogenic VOC emission from India may probably be the first of its kind from this part of the world. - Isoprene flux (diurnal and seasonal) from some tropical tree species was estimated and a regional comparison was made.

  3. The ethics of reviving long extinct species.

    Science.gov (United States)

    Sandler, Ronald

    2014-04-01

    There now appears to be a plausible pathway for reviving species that have been extinct for several decades, centuries, or even millennia. I conducted an ethical analysis of de-extinction of long extinct species. I assessed several possible ethical considerations in favor of pursuing de-extinction: that it is a matter of justice; that it would reestablish lost value; that it would create new value; and that society needs it as a conservation last resort. I also assessed several possible ethical arguments against pursuing de-extinction: that it is unnatural; that it could cause animal suffering; that it could be ecologically problematic or detrimental to human health; and that it is hubristic. There are reasons in favor of reviving long extinct species, and it can be ethically acceptable to do so. However, the reasons in favor of pursuing de-extinction do not have to do with its usefulness in species conservation; rather, they concern the status of revived species as scientific and technological achievements, and it would be ethically problematic to promote de-extinction as a significant conservation strategy, because it does not prevent species extinctions, does not address the causes of extinction, and could be detrimental to some species conservation efforts. Moreover, humanity does not have a responsibility or obligation to pursue de-extinction of long extinct species, and reviving them does not address any urgent problem. Therefore, legitimate ecological, political, animal welfare, legal, or human health concerns associated with a de-extinction (and reintroduction) must be thoroughly addressed for it to be ethically acceptable. © 2013 Society for Conservation Biology.

  4. Relation of chironomids with Aeromonas species

    Directory of Open Access Journals (Sweden)

    Sivan eLaviad

    2016-05-01

    Full Text Available Chironomids (Diptera: Chironomidae, also known as non-biting midges, are one of the most abundant groups of insects in aquatic habitats. They undergo a complete metamorphosis of four life stages of which three are aquatic (egg, larva, pupa, and the adult emerges into the air. Chironomids serve as a natural reservoir of Aeromonas and Vibrio cholerae species. Here we review existing knowledge about the mutual relations between Aeromonas species and chironomids. Using 454-pyrosequencing of the 16S rRNA gene, we found that the prevalence of Aeromonas species in the insects’ egg masses and larvae was 1.6% and 3.3% of the insects’ endogenous microbiota, respectively. Aeromonas abundance per egg mass remained stable during a six-month period of bacterial monitoring. Different Aeromonas species were isolated and some demonstrated the ability to degrade the insect’s egg masses and to prevent eggs hatching. Chitinase was identified as the enzyme responsible for the egg mass degradation. Different Aeromonas species isolated from chironomids demonstrated the potential to protect their host from toxic metals. Aeromonas is a causative agent of fish infections. Fish are frequently recorded as feeding on chironomids. Thus, fish might be infected with Aeromonas species via chironomid consumption. Aeromonas strains are also responsible for causing gastroenteritis and wound infections in humans. Different virulence genes were identified in Aeromonas species isolated from chironomids. Chironomids may infest drinking water reservoirs, hence be the source of pathogenic Aeromonas strains in drinking water. Chironomids and Aeromonas species have a complicated mutual relationship.

  5. Phylogeny and species traits predict bird detectability

    Science.gov (United States)

    Solymos, Peter; Matsuoka, Steven M.; Stralberg, Diana; Barker, Nicole K. S.; Bayne, Erin M.

    2018-01-01

    Avian acoustic communication has resulted from evolutionary pressures and ecological constraints. We therefore expect that auditory detectability in birds might be predictable by species traits and phylogenetic relatedness. We evaluated the relationship between phylogeny, species traits, and field‐based estimates of the two processes that determine species detectability (singing rate and detection distance) for 141 bird species breeding in boreal North America. We used phylogenetic mixed models and cross‐validation to compare the relative merits of using trait data only, phylogeny only, or the combination of both to predict detectability. We found a strong phylogenetic signal in both singing rates and detection distances; however the strength of phylogenetic effects was less than expected under Brownian motion evolution. The evolution of behavioural traits that determine singing rates was found to be more labile, leaving more room for species to evolve independently, whereas detection distance was mostly determined by anatomy (i.e. body size) and thus the laws of physics. Our findings can help in disentangling how complex ecological and evolutionary mechanisms have shaped different aspects of detectability in boreal birds. Such information can greatly inform single‐ and multi‐species models but more work is required to better understand how to best correct possible biases in phylogenetic diversity and other community metrics.

  6. The temporal variability of species densities

    International Nuclear Information System (INIS)

    Redfearn, A.; Pimm, S.L.

    1993-01-01

    Ecologists use the term 'stability' to mean to number of different things (Pimm 1984a). One use is to equate stability with low variability in population density over time (henceforth, temporal variability). Temporal variability varies greatly from species to species, so what effects it? There are at least three sets of factors: the variability of extrinsic abiotic factors, food web structure, and the intrinsic features of the species themselves. We can measure temporal variability using at least three statistics: the coefficient of variation of density (CV); the standard deviation of the logarithms of density (SDL); and the variance in the differences between logarithms of density for pairs of consecutive years (called annual variability, hence AV, b y Wolda 1978). There are advantages and disadvantages to each measure (Williamson 1984), though in our experience, the measures are strongly correlated across sets of taxonomically related species. The increasing availability of long-term data sets allows one to calculate these statistics for many species and so to begin to understand the various causes of species differences in temporal variability

  7. Malaria vector species in Colombia: a review

    Directory of Open Access Journals (Sweden)

    James Montoya-Lerma

    2011-08-01

    Full Text Available Here we present a comprehensive review of the literature on the vectorial importance of the major Anopheles malaria vectors in Colombia. We provide basic information on the geographical distribution, altitudinal range, immature habitats, adult behaviour, feeding preferences and anthropophily, endophily and infectivity rates. We additionally review information on the life cycle, longevity and population fluctuation of Colombian Anopheles species. Emphasis was placed on the primary vectors that have been epidemiologically incriminated in malaria transmission: Anopheles darlingi, Anopheles albimanus and Anopheles nuneztovari. The role of a selection of local, regional or secondary vectors (e.g., Anopheles pseudopunctipennis and Anopheles neivai is also discussed. We highlight the importance of combining biological, morphological and molecular data for the correct taxonomical determination of a given species, particularly for members of the species complexes. We likewise emphasise the importance of studying the bionomics of primary and secondary vectors along with an examination of the local conditions affecting the transmission of malaria. The presence and spread of the major vectors and the emergence of secondary species capable of transmitting human Plasmodia are of great interest. When selecting control measures, the anopheline diversity in the region must be considered. Variation in macroclimate conditions over a species' geographical range must be well understood and targeted to plan effective control measures based on the population dynamics of the local Anopheles species.

  8. Inducible Clindamycin Resistance in Staphylococcus Species

    International Nuclear Information System (INIS)

    Afridi, F. I.; Zeb, M.; Farooqi, B. J.; Murtaza, G.; Hussain, A.

    2014-01-01

    Objective: To determine the frequency of inducible clindamycin resistance in clinical isolates of Staphylococcus species by phenotypic D-test. Study Design: Observational study. Place and Duration of Study: Ziauddin University Hospital, Karachi, from July to December 2011. Methodology: Consecutive clinical isolates of Staphylococcus species were collected and identified by conventional microbiological techniques. Antimicrobial susceptibility testing and inducible clindamycin resistance was carried out by performing D-test using CLSI criteria. Methicillin resistance was detected by using Cefoxitin disk as a surrogate marker. Statistical analysis was performed by SPSS version-17. Results: A total of 667 clinical isolates of Staphylococcus species were obtained during the study period. In these isolates, 177 (26.5%) were Staphylococcus aureus, and 490 (73.5%) were coagulase negative Staphylococci. The total frequency of inducible clindamycin resistance among isolates of Staphylococcus species was 120/667 (18%). Frequency of inducible clindamycin resistance among coagulase negative Staphylococci group and Staphylococcus aureus group were 18.57% and 16.38% respectively. Median age of patients in D-test positive group was 19.5 (1 - 54) years. Conclusion: The frequency of inducible clindamycin resistance among Staphylococcus species may differ in different hospital setup. Clinical microbiology laboratories should implement testing simple and effective D-test on all Staphylococcus species. D-test positive isolates should be reported clindamycin resistant to decrease treatment failure. (author)

  9. Chilli anthracnose disease caused by Colletotrichum species.

    Science.gov (United States)

    Than, Po Po; Prihastuti, Haryudian; Phoulivong, Sitthisack; Taylor, Paul W J; Hyde, Kevin D

    2008-10-01

    Anthracnose disease is one of the major economic constraints to chilli production worldwide, especially in tropical and subtropical regions. Accurate taxonomic information is necessary for effective disease control management. In the Colletotrichum patho-system, different Colletotrichum species can be associated with anthracnose of the same host. Little information is known concerning the interactions of the species associated with the chilli anthracnose although several Colletotrichum species have been reported as causal agents of chilli anthracnose disease worldwide. The ambiguous taxonomic status of Colletotrichum species has resulted in inaccurate identification which may cause practical problems in plant breeding and disease management. Although the management and control of anthracnose disease are still being extensively researched, commercial cultivars of Capsicum annuum that are resistant to the pathogens that cause chilli anthracnose have not yet been developed. This paper reviews the causal agents of chilli anthracnose, the disease cycle, conventional methods in identification of the pathogen and molecular approaches that have been used for the identification of Colletotrichum species. Pathogenetic variation and population structure of the causal agents of chilli anthracnose along with the current taxonomic status of Colletotrichum species are discussed. Future developments leading to the disease management strategies are suggested.

  10. Phytochemistry and Pharmacology of Berberis Species

    Science.gov (United States)

    Mokhber-Dezfuli, Najmeh; Saeidnia, Soodabeh; Gohari, Ahmad Reza; Kurepaz-Mahmoodabadi, Mahdieh

    2014-01-01

    The genus Berberis (Berberidaceae) includes about 500 species worldwide, some of which are widely cultivated in the north-eastern regions of Iran. This genus consists of spiny deciduous evergreen shrubs, characterized by yellow wood and flowers. The cultivation of seedless barberry in South Khorasan goes back to two hundred years ago. Medicinal properties for all parts of these plants have been reported, including: Antimicrobial, antiemetic, antipyretic, antioxidant, anti-inflammatory, anti-arrhythmic, sedative, anti-cholinergic, cholagogic, anti-leishmaniasis, and anti-malaria. The main compounds found in various species of Berberis, are berberine and berbamine. Phytochemical analysis of various species of this genus revealed the presence of alkaloids, tannins, phenolic compounds, sterols and triterpenes. Although there are some review articles on Berberis vulgaris (as the most applied species), there is no review on the phytochemical and pharmacological activities of other well-known species of the genus Berberis. For this reason, the present review mainly focused on the diverse secondary metabolites of various species of this genus and the considerable pharmacological and biological activities together with a concise story of the botany and cultivation. PMID:24600191

  11. Rare species are valued big time.

    Directory of Open Access Journals (Sweden)

    Elena Angulo

    Full Text Available BACKGROUND: It has recently been postulated that the value humans place on rarity could cause the extinction of rare species. This is because people are willing to pay the high costs of exploiting the last individuals. Many hobbies, such as ecotourism or the keeping of exotic pets may cause this effect--known as the anthropogenic Allee effect. However, the entire theory relies on the insofar undemonstrated assumption that people do value rarity. METHODOLOGY/PRINCIPAL FINDINGS: In order to quantify how much people valued rare species relative to common ones, we created online slideshows of photographs of either rare or common species on an Internet web site. The slideshow with photographs of rare species attracted more visitors, and visitors spent, in general, more time waiting to view it. CONCLUSIONS/SIGNIFICANCE: We provide evidence that people value rare more than common species. As we did not target consumers of a specific market, this finding suggests that the anthropogenic Allee effect is likely be driven by a large part of the population. Given the substantial participation in our online experiment, we highlight the potential of the world wide web resource as a tool for conservation action. However, the evidence presented here that the general public value rare species, combined with the assumption that anthropogenic Allee effect is operating, implies that conservationists should be prudent when using rarity to promote conservation.

  12. Assessing species saturation: conceptual and methodological challenges.

    Science.gov (United States)

    Olivares, Ingrid; Karger, Dirk N; Kessler, Michael

    2018-05-07

    Is there a maximum number of species that can coexist? Intuitively, we assume an upper limit to the number of species in a given assemblage, or that a lineage can produce, but defining and testing this limit has proven problematic. Herein, we first outline seven general challenges of studies on species saturation, most of which are independent of the actual method used to assess saturation. Among these are the challenge of defining saturation conceptually and operationally, the importance of setting an appropriate referential system, and the need to discriminate among patterns, processes and mechanisms. Second, we list and discuss the methodological approaches that have been used to study species saturation. These approaches vary in time and spatial scales, and in the variables and assumptions needed to assess saturation. We argue that assessing species saturation is possible, but that many studies conducted to date have conceptual and methodological flaws that prevent us from currently attaining a good idea of the occurrence of species saturation. © 2018 Cambridge Philosophical Society.

  13. Reptilian reovirus: a new fusogenic orthoreovirus species

    International Nuclear Information System (INIS)

    Duncan, Roy.; Corcoran, Jennifer; Shou Jingyun; Stoltz, Don

    2004-01-01

    The fusogenic subgroup of orthoreoviruses contains most of the few known examples of non-enveloped viruses capable of inducing syncytium formation. The only unclassified orthoreoviruses at the species level represent several fusogenic reptilian isolates. To clarify the relationship of reptilian reoviruses (RRV) to the existing fusogenic and nonfusogenic orthoreovirus species, we undertook a characterization of a python reovirus isolate. Biochemical, biophysical, and biological analyses confirmed the designation of this reptilian reovirus (RRV) isolate as an unclassified fusogenic orthoreovirus. Sequence analysis revealed that the RRV S1 and S3 genome segments contain a novel conserved 5'-terminal sequence not found in other orthoreovirus species. In addition, the gene arrangement and the coding potential of the bicistronic RRV S1 genome segment differ from that of established orthoreovirus species, encoding a predicted homologue of the reovirus cell attachment protein and a unique 125 residue p14 protein. The RRV S3 genome segment encodes a homologue of the reovirus sigma-class major outer capsid protein, although it is highly diverged from that of other orthoreovirus species (amino acid identities of only 16-25%). Based on sequence analysis, biological properties, and phylogenetic analysis, we propose this python reovirus be designated as the prototype strain of a fifth species of orthoreoviruses, the reptilian reoviruses

  14. Diversity of cuticular wax among Salix species and Populus species hybrids.

    Science.gov (United States)

    Cameron, Kimberly D; Teece, Mark A; Bevilacqua, Eddie; Smart, Lawrence B

    2002-08-01

    The leaf cuticular waxes of three Salix species and two Populus species hybrids, selected for their ability to produce high amounts of biomass, were characterized. Samples were extracted in CH(2)Cl(2) three times over the growing season. Low kV SEM was utilized to observe differences in the ultrastructure of leaf surfaces from each clone. Homologous series of wax components were classified into organic groups, and the variation in wax components due to clone, sample time, and their interaction was identified. All Salix species and Populus species hybrids showed differences in total wax load at each sampling period, whereas the pattern of wax deposition over time differed only between the Salix species. A strong positive relationship was identified between the entire homologous series of alcohols and total wax load in all clones. Similarly strong relationships were observed between fatty acids and total wax load as well as fatty acids and alcohols in two Salix species and one Populus species hybrid. One Salix species, S. dasyclados, also displayed a strong positive relationship between alcohols and alkanes. These data indicate that species grown under the same environmental conditions produce measurably different cuticular waxes and that regulation of wax production appears to be different in each species. The important roles cuticular waxes play in drought tolerance, pest, and pathogen resistance, as well as the ease of wax extraction and analysis, strongly suggest that the characteristics of the cuticular wax may prove to be useful selectable traits in a breeding program.

  15. Reconciliation with non-binary species trees.

    Science.gov (United States)

    Vernot, Benjamin; Stolzer, Maureen; Goldman, Aiton; Durand, Dannie

    2008-10-01

    Reconciliation extracts information from the topological incongruence between gene and species trees to infer duplications and losses in the history of a gene family. The inferred duplication-loss histories provide valuable information for a broad range of biological applications, including ortholog identification, estimating gene duplication times, and rooting and correcting gene trees. While reconciliation for binary trees is a tractable and well studied problem, there are no algorithms for reconciliation with non-binary species trees. Yet a striking proportion of species trees are non-binary. For example, 64% of branch points in the NCBI taxonomy have three or more children. When applied to non-binary species trees, current algorithms overestimate the number of duplications because they cannot distinguish between duplication and incomplete lineage sorting. We present the first algorithms for reconciling binary gene trees with non-binary species trees under a duplication-loss parsimony model. Our algorithms utilize an efficient mapping from gene to species trees to infer the minimum number of duplications in O(|V(G) | x (k(S) + h(S))) time, where |V(G)| is the number of nodes in the gene tree, h(S) is the height of the species tree and k(S) is the size of its largest polytomy. We present a dynamic programming algorithm which also minimizes the total number of losses. Although this algorithm is exponential in the size of the largest polytomy, it performs well in practice for polytomies with outdegree of 12 or less. We also present a heuristic which estimates the minimal number of losses in polynomial time. In empirical tests, this algorithm finds an optimal loss history 99% of the time. Our algorithms have been implemented in NOTUNG, a robust, production quality, tree-fitting program, which provides a graphical user interface for exploratory analysis and also supports automated, high-throughput analysis of large data sets.

  16. The status of Botryosphaeriaceae species infecting grapevines

    Directory of Open Access Journals (Sweden)

    Jose Ramón URBEZ-TORRES

    2011-12-01

    Full Text Available Normal 0 MicrosoftInternetExplorer4 Normal 0 MicrosoftInternetExplorer4 Species in the Botryosphaeriaceae have a cosmopolitan distribution, and occur on a wide range of annual and perennial hosts including grapevines. To date, morphological and taxonomic studies, as well as analyses of nucleotide sequences of multiple genes, have allowed the identification of at least 21 different species in the Botryosphaeriaceae occurring in grapevines worldwide. Grapevine disease symptoms caused by members of this family include leaf spots, fruit rots, shoot dieback, bud necrosis, vascular discoloration of the wood, and perennial cankers, and their current status as pathogens is reviewed. Additionally, the disease name Botryosphaeria dieback is proposed here to describe the different grapevine trunk disease symptoms caused by species of Botryosphaeriaceae. Much has been written during the last decade about the association between species in the Botryosphaeriaceae and grapevine trunk diseases, which has contributed to a better understanding of the role that these fungal taxa play in grapevine diseases. Although virulence has been shown to vary between species and isolates of the same species in different countries, these fungi have become well-recognized as important grapevine pathogens worldwide. Latest and novel findings from studies conducted in different countries, on disease etiology and species distribution, epidemiology and biology are discussed. Much progress has been achieved in the development and implementation of novel diagnostic and detection techniques.Vineyard sanitation techniques, as well as chemical, biological, and cultural control strategies available at the present time to reduce the infection caused by botryosphaeriaceous fungi, are presented in this review. 

  17. New species of Auritella (Inocybaceae) from Cameroon, with a worldwide key to the known species.

    Science.gov (United States)

    Matheny, P Brandon; Henkel, Terry W; Séné, Olivier; Korotkin, Hailee B; Dentinger, Bryn T M; Aime, M Catherine

    2017-12-01

    Two new species in the genus Auritella ( Inocybaceae ) are described as new from tropical rainforest in Cameroon. Descriptions, photographs, line drawings, and a worldwide taxonomic key to the described species of Auritella are presented. Phylogenetic analysis of 28S rDNA and rpb2 nucleotide sequence data suggests at least five phylogenetic species that can be ascribed to Auritella occur in the region comprising Cameroon and Gabon and constitute a strongly supported monophyletic subgroup within the genus. Phylogenetic analysis of ITS data supports the conspecificity of numerous collections attributed to the two new species as well as the monophyly of Australian species of Auritella . This work raises the known number of described species of Auritella to thirteen worldwide, four of which occur in tropical Africa, one in tropical India, and eight in temperate and tropical regions of Australia. This is the first study to confirm an ectomycorrhizal status of Auritella using molecular data.

  18. Molluscan indicator species and their potential use in ecological status assessment using species distribution modeling.

    Science.gov (United States)

    Moraitis, Manos L; Tsikopoulou, Irini; Geropoulos, Antonios; Dimitriou, Panagiotis D; Papageorgiou, Nafsika; Giannoulaki, Marianna; Valavanis, Vasilis D; Karakassis, Ioannis

    2018-05-24

    Marine habitat assessment using indicator species through Species Distribution Modeling (SDM) was investigated. The bivalves: Corbula gibba and Flexopecten hyalinus were the indicator species characterizing disturbed and undisturbed areas respectively in terms of chlorophyll a concentration in Greece. The habitat suitability maps of these species reflected the overall ecological status of the area. The C. gibba model successfully predicted the occurrence of this species in areas with increased physical disturbance driven by chlorophyll a concentration, whereas the habitat map for F. hyalinus showed an increased probability of occurrence in chlorophyll-poor areas, affected mainly by salinity. We advocate the use of C. gibba as a proxy for eutrophication and the incorporation of this species in monitoring studies through SDM methods. For the Mediterranean Sea we suggest the use of F. hyalinus in SDM as an indicator of environmental stability and a possible forecasting tool for salinity fluctuations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Reproductive Impacts of Endocrine-Disrupting Chemicals on Wildlife Species: Implications for Conservation of Endangered Species.

    Science.gov (United States)

    Tubbs, Christopher W; McDonough, Caitlin E

    2018-02-15

    Wildlife have proven valuable to our understanding of the potential effects of endocrine-disrupting chemicals (EDCs) on human health by contributing considerably to our understanding of the mechanisms and consequences of EDC exposure. But the threats EDCs present to populations of wildlife species themselves are significant, particularly for endangered species whose existence is vulnerable to any reproductive perturbation. However, few studies address the threats EDCs pose to endangered species owing to challenges associated with their study. Here, we highlight those barriers and review the available literature concerning EDC effects on endangered species. Drawing from other investigations into nonthreatened wildlife species, we highlight opportunities for new approaches to advance our understanding and potentially mitigate the effects of EDCs on endangered species to enhance their fertility.

  20. Biological review of 82 species of coral petitioned to be included in the Endangered Species Act

    Science.gov (United States)

    Brainard, Russell E.; Birkeland, Charles; Eakin, C. Mark; McElhany, Paul; Miller, Margaret W.; Patterson, Matt; Piniak, G.A.

    2011-01-01

    list 83 coral species as threatened or endangered under the U.S. Endangered Species Act. The petition was based on a predicted decline in available habitat for the species, citing anthropogenic climate change and ocean acidification as the lead factors among the various stressors responsible for the potential decline. The NMFS identified 82 of the corals as candidate species, finding that the petition provided substantive information for a potential listing of these species. The NMFS established a Biological Review Team (BRT) to prepare this Status Review Report that examines the status of these 82 candidate coral species and evaluates extinction risk for each of them. This document makes no recommendations for listing, as that is a separate evaluation to be conducted by the NMFS.

  1. Proactive Conservation Program: Species of Concern :: NOAA Fisheries

    Science.gov (United States)

    Invertebrates & Plants Species of Concern Threatened & Endangered Health & Stranding Marine Mammals : Species of Concern Species of Concern List | Grants and Technical Resources/Links bluefin tuna Bluefin Tuna (Thunnus thynnus) Photo: NOAA Species of Concern are those species about which we have some

  2. Effects of habitat structure and altitudinal gradients on avian species ...

    African Journals Online (AJOL)

    ... effect on bird species diversity. Bird species diversity increased with increase in tree height. A significant decline in bird species diversity with increased number of trees and canopy cover was noted. This result probably suggests an accumulation of forest edge species and generalist species in the less forested habitat.

  3. Delineating probabilistic species pools in ecology and biogeography

    OpenAIRE

    Karger, Dirk Nikolaus; Cord, Anna F; Kessler, Michael; Kreft, Holger; Kühn, Ingolf; Pompe, Sven; Sandel, Brody; Sarmento Cabral, Juliano; Smith, Adam B; Svenning, Jens-Christian; Tuomisto, Hanna; Weigelt, Patrick; Wesche, Karsten

    2016-01-01

    Aim To provide a mechanistic and probabilistic framework for defining the species pool based on species-specific probabilities of dispersal, environmental suitability and biotic interactions within a specific temporal extent, and to show how probabilistic species pools can help disentangle the geographical structure of different community assembly processes. Innovation Probabilistic species pools provide an improved species pool definition based on probabilities in conjuncti...

  4. Two new species of the Phanaeus endymion species group (Coleoptera, Scarabaeidae, Scarabaeinae).

    Science.gov (United States)

    Moctezuma, Victor; Sánchez-Huerta, José Luis; Halffter, Gonzalo

    2017-01-01

    Phanaeus bravoensis sp. n. is described from the coniferous-oak forests in the state of Guerrero, and P. huichol sp. n. from coniferous-oak forests and cloud forests in Jalisco and Nayarit. The new species are closely related to P. halffterorum and P. zoque respectively. Morphological trait combination, geographic distribution, and trophic habits show important differences among the studied species. A distribution map and an updated key to separate the species are included.

  5. Discordance between morphological and molecular species boundaries among Caribbean species of the reef sponge Callyspongia

    OpenAIRE

    DeBiasse, Melissa B; Hellberg, Michael E

    2015-01-01

    Sponges are among the most species-rich and ecologically important taxa on coral reefs, yet documenting their diversity is difficult due to the simplicity and plasticity of their morphological characters. Genetic attempts to identify species are hampered by the slow rate of mitochondrial sequence evolution characteristic of sponges and some other basal metazoans. Here we determine species boundaries of the Caribbean coral reef sponge genus Callyspongia using a multilocus, model-based approach...

  6. Indicator species of essential forest tree species in the Burdur district.

    Science.gov (United States)

    Negiz, Mehmet Güvenç; Eser, Yunus; Kuzugüdenll, Emre; Izkan, Kürşad

    2015-01-01

    The forests of Burdur district for long have been subjected to over grazing and individual selection. As a result of this, majority of the forest areas in the district were degraded. In the district, afforestation efforts included majority of forestry implementations. It is well known that selecting suitable species plays an important role for achieving afforestation efforts. In this context, knowing the indicator species among the target species would be used in afforestation efforts, studies on the interrelationships between environmental factors and target species distribution is vital for selecting suitable species for a given area. In this study, Anatolian Black pine (Pinus nigra), Red pine (Pinus brutia), Crimean juniper (Juniperus excelsa) and Taurus cedar (Cedrus libani), essential tree species, were considered as target species. The data taken from 100 sample plots in Burdur district was used. Interspecific correlation analysis was performed to determine the positive and negative indicator species among each of the target species. As a result of ICA, 2 positive (Berberis crataegina, Juniperus oxycedrus), 2 negative (Phillyrea latifolia, Quercus coccifera) for Crimean Juniper, I positive (Juniperus oxycedrus), 3 negative (Onopordium acanthium, Fraxinus ornus, Phillyrea latifolia) for Anatolian black pine, 3 positive (Paliurus spina-christi, Quercus coccifer, Crataegus orientalis), 2 negative (Berberis crataegina, Astragalus nanus) for Red pine and 3 positive (Berberis crataegina, Rhamnus oleoides, Astragalus prusianus) 2 negative (Paliurus spina-christi, Quercus cerris) for Taurus cedarwere defined as indicator plant species. In this way, practical information was obtained for selecting the most suitable species, among the target species, for afforestation efforts in Burdur district.

  7. Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

    Directory of Open Access Journals (Sweden)

    Alexander Bjarnason

    2017-08-01

    Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

  8. Two-species occupancy modeling accounting for species misidentification and nondetection

    Science.gov (United States)

    Chambert, Thierry; Grant, Evan H. Campbell; Miller, David A. W.; Nichols, James; Mulder, Kevin P.; Brand, Adrianne B,

    2018-01-01

    1. In occupancy studies, species misidentification can lead to false positive detections, which can cause severe estimator biases. Currently, all models that account for false positive errors only consider omnibus sources of false detections and are limited to single species occupancy. 2. However, false detections for a given species often occur because of the misidentification with another, closely-related species. To exploit this explicit source of false positive detection error, we develop a two-species occupancy model that accounts for misidentifications between two species of interest. As with other false positive models, identifiability is greatly improved by the availability of unambiguous detections at a subset of site-occasions. Here, we consider the case where some of the field observations can be confirmed using laboratory or other independent identification methods (“confirmatory data”). 3. We performed three simulation studies to (1) assess the model’s performance under various realistic scenarios, (2) investigate the influence of the proportion of confirmatory data on estimator accuracy, and (3) compare the performance of this two-species model with that of the single-species false positive model. The model shows good performance under all scenarios, even when only small proportions of detections are confirmed (e.g., 5%). It also clearly outperforms the single-species model.

  9. Bias correction in species distribution models: pooling survey and collection data for multiple species.

    Science.gov (United States)

    Fithian, William; Elith, Jane; Hastie, Trevor; Keith, David A

    2015-04-01

    Presence-only records may provide data on the distributions of rare species, but commonly suffer from large, unknown biases due to their typically haphazard collection schemes. Presence-absence or count data collected in systematic, planned surveys are more reliable but typically less abundant.We proposed a probabilistic model to allow for joint analysis of presence-only and survey data to exploit their complementary strengths. Our method pools presence-only and presence-absence data for many species and maximizes a joint likelihood, simultaneously estimating and adjusting for the sampling bias affecting the presence-only data. By assuming that the sampling bias is the same for all species, we can borrow strength across species to efficiently estimate the bias and improve our inference from presence-only data.We evaluate our model's performance on data for 36 eucalypt species in south-eastern Australia. We find that presence-only records exhibit a strong sampling bias towards the coast and towards Sydney, the largest city. Our data-pooling technique substantially improves the out-of-sample predictive performance of our model when the amount of available presence-absence data for a given species is scarceIf we have only presence-only data and no presence-absence data for a given species, but both types of data for several other species that suffer from the same spatial sampling bias, then our method can obtain an unbiased estimate of the first species' geographic range.

  10. Seasonal species interactions minimize the impact of species turnover on the likelihood of community persistence.

    Science.gov (United States)

    Saavedra, Serguei; Rohr, Rudolf P; Fortuna, Miguel A; Selva, Nuria; Bascompte, Jordi

    2016-04-01

    Many of the observed species interactions embedded in ecological communities are not permanent, but are characterized by temporal changes that are observed along with abiotic and biotic variations. While work has been done describing and quantifying these changes, little is known about their consequences for species coexistence. Here, we investigate the extent to which changes of species composition impact the likelihood of persistence of the predator-prey community in the highly seasonal Białowieza Primeval Forest (northeast Poland), and the extent to which seasonal changes of species interactions (predator diet) modulate the expected impact. This likelihood is estimated extending recent developments on the study of structural stability in ecological communities. We find that the observed species turnover strongly varies the likelihood of community persistence between summer and winter. Importantly, we demonstrate that the observed seasonal interaction changes minimize the variation in the likelihood of persistence associated with species turnover across the year. We find that these community dynamics can be explained as the coupling of individual species to their environment by minimizing both the variation in persistence conditions and the interaction changes between seasons. Our results provide a homeostatic explanation for seasonal species interactions and suggest that monitoring the association of interactions changes with the level of variation in community dynamics can provide a good indicator of the response of species to environmental pressures.

  11. Socially-parasitic Myrmica species (Hymenoptera, Formicidae) of Himalaya, with the description of a new species.

    Science.gov (United States)

    Bharti, Himender; Radchenko, Alexander; Sasi, Sishal

    2016-01-01

    A new socially-parasitic species, Myrmica latra sp. n. is described based on a queen and male from Indian Himalaya. Its queen differs from other species by the distinctly narrower petiole and postpetiole, blunt and non-divergent propodeal spines, and a darker body colour. The taxonomic position of the three known Himalayan socially-parasitic Myrmica species is discussed, and Myrmica ereptrix Bolton 1988 is transferred to the smythiesii species-group. It is supposed that Myrmica nefaria Bharti 2012 is a temporary social parasite, but Myrmica ereptrix and Myrmica latra sp. n. are permanent social parasites, and a key for their identification is provided.

  12. Onychiurid species from Wanda Mountains in China, with descriptions of two new species (Collembola, Onychiuridae)

    Science.gov (United States)

    Sun, Xin; Wu, Donghui

    2014-01-01

    Abstract A checklist of onychiurid species from the Wanda Mountains in China is presented. Eighteen species belonging to twelve genera have been found, including two new species. Bionychiurus qinglongensis sp. n. can be easily distinguished from other known species of the genus by the absence of pseudocelli on Th. I tergum and fewer number of vesicles in postantennal organ. Onychiurus heilongjiangensis sp. n. is diagnosed by pseudocellar formulae as 32/133/33352 dorsally and 3/011/31120 ventrally, parapseudocellar formula as 0/000/111001+1m, ratio of anal spine/unguis as 0.6, unguiculus without inner basal lamella, and male ventral organ absent. PMID:25147452

  13. Reconciliation of Gene and Species Trees

    Directory of Open Access Journals (Sweden)

    L. Y. Rusin

    2014-01-01

    Full Text Available The first part of the paper briefly overviews the problem of gene and species trees reconciliation with the focus on defining and algorithmic construction of the evolutionary scenario. Basic ideas are discussed for the aspects of mapping definitions, costs of the mapping and evolutionary scenario, imposing time scales on a scenario, incorporating horizontal gene transfers, binarization and reconciliation of polytomous trees, and construction of species trees and scenarios. The review does not intend to cover the vast diversity of literature published on these subjects. Instead, the authors strived to overview the problem of the evolutionary scenario as a central concept in many areas of evolutionary research. The second part provides detailed mathematical proofs for the solutions of two problems: (i inferring a gene evolution along a species tree accounting for various types of evolutionary events and (ii trees reconciliation into a single species tree when only gene duplications and losses are allowed. All proposed algorithms have a cubic time complexity and are mathematically proved to find exact solutions. Solving algorithms for problem (ii can be naturally extended to incorporate horizontal transfers, other evolutionary events, and time scales on the species tree.

  14. SPECIES DIVERSITY AND STABILITY OF BIRD COMMUNITIES

    Directory of Open Access Journals (Sweden)

    Matsyura M.V.

    2011-12-01

    Full Text Available When comparing the suggested stability indicators, we obtained statistically significant correlations for indicators of annual stability of species and total number and standard deviation of the logarithm of the number. Annual Stability Index can be applied with a high degree of reliability as a characteristic of the averaged structure of the community and its pyramid of abundances. The results of correlation analysis confirm our assumptions about the correlation between stability over the years and indices of species diversity and relative uniformity.The final task of the study was to create a mathematical model of stability, where the independent variables are the indices of species diversity. The calculation of these indices allows forecasting birds’ community stability. According to the result of multiple regression for the indicators of diversity and stability of the breeding birds’ community highest correlation coefficients were obtained fro Shannon index and Simpson's dominance Index.Community stability could be determined by its overall species diversity. When considering the stability of community its diversity should be considered as a combination of uniformity of their total number and number of species. The most suitable predictors for the community stability were the nonparametric index of dominance and information-statistical indices, since they considered simultaneously evenness and richness. The community stability is subject of the complexity of its internal communications pattern.

  15. Diversity in protein glycosylation among insect species.

    Directory of Open Access Journals (Sweden)

    Gianni Vandenborre

    Full Text Available BACKGROUND: A very common protein modification in multicellular organisms is protein glycosylation or the addition of carbohydrate structures to the peptide backbone. Although the Class of the Insecta is the largest animal taxon on Earth, almost all information concerning glycosylation in insects is derived from studies with only one species, namely the fruit fly Drosophila melanogaster. METHODOLOGY/PRINCIPAL FINDINGS: In this report, the differences in glycoproteomes between insects belonging to several economically important insect orders were studied. Using GNA (Galanthus nivalis agglutinin affinity chromatography, different sets of glycoproteins with mannosyl-containing glycan structures were purified from the flour beetle (Tribolium castaneum, the silkworm (Bombyx mori, the honeybee (Apis mellifera, the fruit fly (D. melanogaster and the pea aphid (Acyrthosiphon pisum. To identify and characterize the purified glycoproteins, LC-MS/MS analysis was performed. For all insect species, it was demonstrated that glycoproteins were related to a broad range of biological processes and molecular functions. Moreover, the majority of glycoproteins retained on the GNA column were unique to one particular insect species and only a few glycoproteins were present in the five different glycoprotein sets. Furthermore, these data support the hypothesis that insect glycoproteins can be decorated with mannosylated O-glycans. CONCLUSIONS/SIGNIFICANCE: The results presented here demonstrate that oligomannose N-glycosylation events are highly specific depending on the insect species. In addition, we also demonstrated that protein O-mannosylation in insect species may occur more frequently than currently believed.

  16. Pain, Cannabis Species, and Cannabis Use Disorders

    Science.gov (United States)

    Cohen, Nicole L.; Heinz, Adrienne J.; Ilgen, Mark; Bonn-Miller, Marcel O.

    2016-01-01

    Objective: The purpose of this study was to examine whether individuals who used medical cannabis for chronic pain were at increased risk for cannabis use problems compared with individuals who used medical cannabis for other reasons (e.g., anxiety, insomnia, and muscle spasms). An additional aim was to determine whether individuals who used cannabis for chronic pain, as well as those who reported greater within-group pain levels, demonstrated a species preference (i.e., sativa, indica, hybrids) and the extent to which species preference was associated with cannabis use problems. Method: Participants were 163 medical cannabis users (77% male), recruited from a medical marijuana dispensary in California, who completed assessments of medical cannabis use motives, history, preferences (species type), and problems, as well as current pain level. Results: Individuals who used cannabis to manage chronic pain experienced fewer cannabis use problems than those who did not use it for pain; among those who used it for pain, the average pain level in the past week was not associated with cannabis use problems. Furthermore, individuals who used cannabis for chronic pain were more likely to use indica over sativa. Preference for indica was associated with fewer cannabis use problems than preference for hybrid species. Conclusions: Individuals who use cannabis to manage chronic pain may be at a lower risk for cannabis use problems, relative to individuals who use it for other indications, potentially as a function of their species preference. PMID:27172585

  17. Bracken: estimating species abundance in metagenomics data

    Directory of Open Access Journals (Sweden)

    Jennifer Lu

    2017-01-01

    Full Text Available Metagenomic experiments attempt to characterize microbial communities using high-throughput DNA sequencing. Identification of the microorganisms in a sample provides information about the genetic profile, population structure, and role of microorganisms within an environment. Until recently, most metagenomics studies focused on high-level characterization at the level of phyla, or alternatively sequenced the 16S ribosomal RNA gene that is present in bacterial species. As the cost of sequencing has fallen, though, metagenomics experiments have increasingly used unbiased shotgun sequencing to capture all the organisms in a sample. This approach requires a method for estimating abundance directly from the raw read data. Here we describe a fast, accurate new method that computes the abundance at the species level using the reads collected in a metagenomics experiment. Bracken (Bayesian Reestimation of Abundance after Classification with KrakEN uses the taxonomic assignments made by Kraken, a very fast read-level classifier, along with information about the genomes themselves to estimate abundance at the species level, the genus level, or above. We demonstrate that Bracken can produce accurate species- and genus-level abundance estimates even when a sample contains multiple near-identical species.

  18. Atomic collisions research with excited atomic species

    International Nuclear Information System (INIS)

    Hoogerland, M.D.; Gulley, R.J.; Colla, M.; Lu, W.; Milic, D.; Baldwin, K.G.H.; Buckman, S.J.

    1999-01-01

    Measurements and calculations of fundamental atomic collision and spectroscopic properties such as collision cross sections, reaction rates, transition probabilities etc. underpin the understanding and operation of many plasma and gas-discharge-based devices and phenomena, for example plasma processing and deposition. In almost all cases the complex series of reactions which sustains the discharge or plasma, or produces the reactive species of interest, has a precursor electron impact excitation, attachment, dissociation or ionisation event. These processes have been extensively studied in a wide range of atomic and molecular species and an impressive data base of collision cross sections and reaction rates now exists. However, most of these measurements are for collisions with stable atomic or molecular species which are initially in their ground electronic state. Relatively little information is available for scattering from excited states or for scattering from unstable molecular radicals. Examples of such species would be metastable excited rare gases, which are often used as buffer gases, or CF 2 radicals formed by electron impact dissociation in a CF 4 plasma processing discharge. We are interested in developing experimental techniques which will enable the quantitative study of such exotic atomic and molecular species. In this talk I would like to outline one such facility which is being used for studies of collisions with metastable He(2 3 S) atoms

  19. Exploring similarities among many species distributions

    Science.gov (United States)

    Simmerman, Scott; Wang, Jingyuan; Osborne, James; Shook, Kimberly; Huang, Jian; Godsoe, William; Simons, Theodore R.

    2012-01-01

    Collecting species presence data and then building models to predict species distribution has been long practiced in the field of ecology for the purpose of improving our understanding of species relationships with each other and with the environment. Due to limitations of computing power as well as limited means of using modeling software on HPC facilities, past species distribution studies have been unable to fully explore diverse data sets. We build a system that can, for the first time to our knowledge, leverage HPC to support effective exploration of species similarities in distribution as well as their dependencies on common environmental conditions. Our system can also compute and reveal uncertainties in the modeling results enabling domain experts to make informed judgments about the data. Our work was motivated by and centered around data collection efforts within the Great Smoky Mountains National Park that date back to the 1940s. Our findings present new research opportunities in ecology and produce actionable field-work items for biodiversity management personnel to include in their planning of daily management activities.

  20. Species richness, area and climate correlates

    DEFF Research Database (Denmark)

    Nogues, David Bravo; Bastos Araujo, Miguel

    2006-01-01

    affects: (1) the selection of climate variables entering a species richness model; and (2) the accuracy of models in predicting species richness in unsampled grid cells. Location Western Europe. Methods Models are developed for European plant, breeding bird, mammal and herptile species richness using...... seven climate variables. Generalized additive models are used to relate species richness, climate and area. Results We found that variation in the grid cell area was large (50 × 50 km: 8-3311 km2; 220 × 220: 193-55,100 km2), but this did not affect the selection of variables in the models. Similarly...... support the assumption that variation in near-equal area cells may be of second-order importance for models explaining or predicting species richness in relation to climate, although there is a possibility that drops in accuracy might increase with grid cell size. The results are, however, contingent...

  1. Pain, Cannabis Species, and Cannabis Use Disorders.

    Science.gov (United States)

    Cohen, Nicole L; Heinz, Adrienne J; Ilgen, Mark; Bonn-Miller, Marcel O

    2016-05-01

    The purpose of this study was to examine whether individuals who used medical cannabis for chronic pain were at increased risk for cannabis use problems compared with individuals who used medical cannabis for other reasons (e.g., anxiety, insomnia, and muscle spasms). An additional aim was to determine whether individuals who used cannabis for chronic pain, as well as those who reported greater within-group pain levels, demonstrated a species preference (i.e., sativa, indica, hybrids) and the extent to which species preference was associated with cannabis use problems. Participants were 163 medical cannabis users (77% male), recruited from a medical marijuana dispensary in California, who completed assessments of medical cannabis use motives, history, preferences (species type), and problems, as well as current pain level. Individuals who used cannabis to manage chronic pain experienced fewer cannabis use problems than those who did not use it for pain; among those who used it for pain, the average pain level in the past week was not associated with cannabis use problems. Furthermore, individuals who used cannabis for chronic pain were more likely to use indica over sativa. Preference for indica was associated with fewer cannabis use problems than preference for hybrid species. Individuals who use cannabis to manage chronic pain may be at a lower risk for cannabis use problems, relative to individuals who use it for other indications, potentially as a function of their species preference.

  2. 77 FR 30261 - Petition To List 83 Species of Coral as Threatened or Endangered Under the Endangered Species Act...

    Science.gov (United States)

    2012-05-22

    ... List 83 Species of Coral as Threatened or Endangered Under the Endangered Species Act (ESA) AGENCY... Diversity (CBD) to list 83 coral species as threatened or endangered under the Endangered Species Act (ESA... the U.S. Endangered Species Act (Status Review Report) and the draft Management Report for 82 Corals...

  3. Current understanding of multi-species biofilms

    DEFF Research Database (Denmark)

    Yang, Liang; Liu, Yang; Wu, Hong

    2011-01-01

    every year worldwide to deal with damage to equipment, contaminations of products, energy losses, and infections in human beings resulted from microbial biofilms. Microorganisms compete, cooperate, and communicate with each other in multi-species biofilms. Understanding the mechanisms of multi......Direct observation of a wide range of natural microorganisms has revealed the fact that the majority of microbes persist as surface-attached communities surrounded by matrix materials, called biofilms. Biofilms can be formed by a single bacterial strain. However, most natural biofilms are actually......-species biofilm formation will facilitate the development of methods for combating bacterial biofilms in clinical, environmental, industrial, and agricultural areas. The most recent advances in the understanding of multi-species biofilms are summarized and discussed in the review....

  4. Assessing species vulnerability to climate change

    Science.gov (United States)

    Pacifici, Michela; Foden, Wendy B.; Visconti, Piero; Watson, James E. M.; Butchart, Stuart H. M.; Kovacs, Kit M.; Scheffers, Brett R.; Hole, David G.; Martin, Tara G.; Akçakaya, H. Resit; Corlett, Richard T.; Huntley, Brian; Bickford, David; Carr, Jamie A.; Hoffmann, Ary A.; Midgley, Guy F.; Pearce-Kelly, Paul; Pearson, Richard G.; Williams, Stephen E.; Willis, Stephen G.; Young, Bruce; Rondinini, Carlo

    2015-03-01

    The effects of climate change on biodiversity are increasingly well documented, and many methods have been developed to assess species' vulnerability to climatic changes, both ongoing and projected in the coming decades. To minimize global biodiversity losses, conservationists need to identify those species that are likely to be most vulnerable to the impacts of climate change. In this Review, we summarize different currencies used for assessing species' climate change vulnerability. We describe three main approaches used to derive these currencies (correlative, mechanistic and trait-based), and their associated data requirements, spatial and temporal scales of application and modelling methods. We identify strengths and weaknesses of the approaches and highlight the sources of uncertainty inherent in each method that limit projection reliability. Finally, we provide guidance for conservation practitioners in selecting the most appropriate approach(es) for their planning needs and highlight priority areas for further assessments.

  5. Autofluorescence in eleocytes of some earthworm species.

    Directory of Open Access Journals (Sweden)

    Barbara Płytycz

    2006-04-01

    Full Text Available Immunocompetent cells of earthworms, coelomocytes, comprise adherent amoebocytes and granular eleocytes (chloragocytes. Both cell populations can be expelled via dorsal pores of adult earthworms by exposure to an electric current (4.5 V for 1 min. Analysis by phase contrast/fluorescence microscopy and flow cytometry demonstrated that eleocyte population of several species exhibits a strong autofluorescence. A high percentage (11-35% of autofluorescent eleocytes was recorded in Allolobophora chlorotica, Dendrodrilus rubidus, Eisenia fetida, and Octolasion sp. (O. cyaneum, O. tyrtaeum tyrtaeum and O. tyrtaeum lacteum. In contrast, autofluorescent coelomocytes were exceptionally scarce (less than 1% in representative Aporrectodea sp. (A. caliginosa and A. longa and Lumbricus sp. (L. castaneus, L. festivus, L. rubellus, L. terrestris. Thus, this paper for the first time describes profound intrinsic fluorescence of eleocytes in some--but not all--earthworm species. The function (if any and inter-species differences of the autofluorescent coelomocytes still remain elusive.

  6. The prairie dog as a keystone species

    Science.gov (United States)

    Kotliar, Natasha B.; Miller, Brian J.; Reading, Richard P.; Clark, Timothy W.; Hoogland, John L.

    2006-01-01

    The prairie dog has a pronounced impact on its grassland ecosystem (King 1955; Uresk and Bjugstad 1983; Miller et al. 1994; Society for Conservation Biology 1994; Wuerthner 1997; Johnsgard 2005). They maintain short vegetation by their grazing and by selective removal of tall plants and shrubs; provide shelter, foraging grounds, and nesting habitat for a diverse array of animals; serve as prey for many predators; and alter soil chemistry.Do these impacts mean that the prairie dog is a keystone species? To investigate, we first scrutinize the definition for a keystone species. We then document both vertebrates and invertebrates that associate with prairie dogs and their colony-sites. We examine ecosystem processes at colony-sites, and then assess whether the prairie dog is a legitimate keystone species. Finally, we explore the implications of keystone status for the conservation of prairie dogs.

  7. Forms and genesis of species abundance distributions

    Directory of Open Access Journals (Sweden)

    Evans O. Ochiaga

    2015-12-01

    Full Text Available Species abundance distribution (SAD is one of the most important metrics in community ecology. SAD curves take a hollow or hyperbolic shape in a histogram plot with many rare species and only a few common species. In general, the shape of SAD is largely log-normally distributed, although the mechanism behind this particular SAD shape still remains elusive. Here, we aim to review four major parametric forms of SAD and three contending mechanisms that could potentially explain this highly skewed form of SAD. The parametric forms reviewed here include log series, negative binomial, lognormal and geometric distributions. The mechanisms reviewed here include the maximum entropy theory of ecology, neutral theory and the theory of proportionate effect.

  8. Taxonomy of Penicillium citrinum and related species

    DEFF Research Database (Denmark)

    Houbraken, J.A.M.P.; Frisvad, Jens Christian; Samson, A.F.

    2010-01-01

    are related to P. citrinum, P. gorlenkoanum is revived, Penicillium hetheringtonii sp. nov. and Penicillium tropicoides sp. nov. are described here as new species, and the combination Penicillium tropicum is proposed. Penicillium hetheringtonii is closely related to P. citrinum and differs in having slightly......Penicillium citrinum and related species have been examined using a combination of partial beta-tubulin, calmodulin and ITS sequence data, extrolite patterns and phenotypic characters. It is concluded that seven species belong to the series Citrina. Penicillium sizovae and Penicillium steckii...... broader stipes, metulae in verticils of four or more and the production of an uncharacterized metabolite, tentatively named PR1-x. Penicillium tropicoides resembles P. tropicum, but differs in the slow maturation of the cleistothecia, slower growth at 30A degrees C and the production of isochromantoxins...

  9. WHITE BLISTER SPECIES (Albuginaceae ON WEEDS

    Directory of Open Access Journals (Sweden)

    Karolina Vrandečić

    2011-06-01

    Full Text Available The obligate fungi inside the family Albuginaceae are widespread world wide and cause white rust or white blister disease. Mycopopulation of weeds has been researched within the project „The role of weeds in epidemiology of row-crop diseases“. The aim of this research was to identify white blister species occurring on weeds in Eastern Croatia. Weed plants with disease symptoms characteristic for white blister species have been collected since 2001 on location Slavonia and Baranja country. Determination of white blister species was based on morphological characters of pathogen and the host. Wilsoniana bliti was determined on Amaranthus retroflexus and Amaranthus hybridus leaves. Capsella bursa pastoris is a host for Albugo candida. Ambrosia artemisiifolia is a host for Pustula sp. and Cirsium arvense was found to be host for Pustula spinulosa. Wilsoniana portulaceae was determined on Portulaca oleracea.

  10. Distribution of Vulpia species (Poaceae in Poland

    Directory of Open Access Journals (Sweden)

    Ludwik Frey

    2011-01-01

    Full Text Available The distribution of four species of the genus Vulpia [V. myuros (L. C.C. Gmel., V. bromoides (L. S.F. Gray, V. ciliata Dumort. and V. geniculata (L. Link] reported in Poland has been studied. Currently, V. myuros and especially V. bromoides are very rare species, and their greatest concentration can be found only in the Lower Silesia region. The number of their localities decreased after 1950 and it seems resonable to include both species in the "red list" of threatened plants in Poland: V. myuros in the EN category, V. bromoides in the CR category. V. ciliata and V. geniculata are very rare ephemerophytes and their localities not confirmed during ca 60 years are of historical interest only.

  11. Computational botany methods for automated species identification

    CERN Document Server

    Remagnino, Paolo; Wilkin, Paul; Cope, James; Kirkup, Don

    2017-01-01

    This book discusses innovative methods for mining information from images of plants, especially leaves, and highlights the diagnostic features that can be implemented in fully automatic systems for identifying plant species. Adopting a multidisciplinary approach, it explores the problem of plant species identification, covering both the concepts of taxonomy and morphology. It then provides an overview of morphometrics, including the historical background and the main steps in the morphometric analysis of leaves together with a number of applications. The core of the book focuses on novel diagnostic methods for plant species identification developed from a computer scientist’s perspective. It then concludes with a chapter on the characterization of botanists' visions, which highlights important cognitive aspects that can be implemented in a computer system to more accurately replicate the human expert’s fixation process. The book not only represents an authoritative guide to advanced computational tools fo...

  12. Capsular Polysaccharide Expression in Commensal Streptococcus Species

    DEFF Research Database (Denmark)

    Skov Sørensen, Uffe B; Yao, Kaihu; Yang, Yonghong

    2016-01-01

    Expression of a capsular polysaccharide is considered a hallmark of most invasive species of bacteria, including Streptococcus pneumoniae, in which the capsule is among the principal virulence factors and is the basis for successful vaccines. Consequently, it was previously assumed that capsule....... pneumoniae evolved by import of cps fragments from commensal Streptococcus species, resulting in a mosaic of genes of different origins. The demonstrated antigenic identity of at least eight of the numerous capsular polysaccharide structures expressed by commensal streptococci with recognized serotypes of S...... of Streptococcus pneumoniae and is the basis for successful vaccines against infections caused by this important pathogen. Contrasting with previous assumptions, this study showed that expression of capsular polysaccharides by the same genetic mechanisms is a general property of closely related species...

  13. Combinatorial Cis-regulation in Saccharomyces Species

    Directory of Open Access Journals (Sweden)

    Aaron T. Spivak

    2016-03-01

    Full Text Available Transcriptional control of gene expression requires interactions between the cis-regulatory elements (CREs controlling gene promoters. We developed a sensitive computational method to identify CRE combinations with conserved spacing that does not require genome alignments. When applied to seven sensu stricto and sensu lato Saccharomyces species, 80% of the predicted interactions displayed some evidence of combinatorial transcriptional behavior in several existing datasets including: (1 chromatin immunoprecipitation data for colocalization of transcription factors, (2 gene expression data for coexpression of predicted regulatory targets, and (3 gene ontology databases for common pathway membership of predicted regulatory targets. We tested several predicted CRE interactions with chromatin immunoprecipitation experiments in a wild-type strain and strains in which a predicted cofactor was deleted. Our experiments confirmed that transcription factor (TF occupancy at the promoters of the CRE combination target genes depends on the predicted cofactor while occupancy of other promoters is independent of the predicted cofactor. Our method has the additional advantage of identifying regulatory differences between species. By analyzing the S. cerevisiae and S. bayanus genomes, we identified differences in combinatorial cis-regulation between the species and showed that the predicted changes in gene regulation explain several of the species-specific differences seen in gene expression datasets. In some instances, the same CRE combinations appear to regulate genes involved in distinct biological processes in the two different species. The results of this research demonstrate that (1 combinatorial cis-regulation can be inferred by multi-genome analysis and (2 combinatorial cis-regulation can explain differences in gene expression between species.

  14. Nocardiopsis species: Incidence, ecological roles and adaptations.

    Science.gov (United States)

    Bennur, Tahsin; Kumar, Ameeta Ravi; Zinjarde, Smita; Javdekar, Vaishali

    2015-05-01

    Members of the genus Nocardiopsis are ecologically versatile and biotechnologically important. They produce a variety of bioactive compounds such as antimicrobial agents, anticancer substances, tumor inducers, toxins and immunomodulators. They also secrete novel extracellular enzymes such as amylases, chitinases, cellulases, β-glucanases, inulinases, xylanases and proteases. Nocardiopsis species are aerobic, Gram-positive, non-acid-fast, catalase-positive actinomycetes with nocardioform substrate mycelia and their aerial mycelia bear long chains of spores. Their DNA possesses high contents of guanine and cytosine. There is a marked variation in properties of the isolates obtained from different ecological niches and their products. An important feature of several species is their halophilic or halotolerant nature. They are associated with a variety of marine and terrestrial biological forms wherein they produce antibiotics and toxins that help their hosts in evading pathogens and predators. Two Nocardiopsis species, namely, N. dassonvillei and N. synnemataformans (among the thirty nine reported ones) are opportunistic human pathogens and cause mycetoma, suppurative infections and abscesses. Nocardiopsis species are present in some plants (as endophytes or surface microflora) and their rhizospheres. Here, they are reported to produce enzymes such as α-amylases and antifungal agents that are effective in warding-off plant pathogens. They are prevalent as free-living entities in terrestrial locales, indoor locations, marine ecosystems and hypersaline habitats on account of their salt-, alkali- and desiccation-resistant behavior. In such natural locations, Nocardiopsis species mainly help in recycling organic compounds. Survival under these diverse conditions is mediated by the production of extracellular enzymes, antibiotics, surfactants, and the accumulation of compatible solutes. The accommodative genomic features of Nocardiopsis species support their existence

  15. The Drosophila bipectinata species complex: degree of sterility and ...

    Indian Academy of Sciences (India)

    sophila bipectinata species complex, comprising four closely related species namely D. bipectinata, D. parabipectinata,. D. malerkotliana and D. ... vials with four males (two each from the respective parental species, to increase the probability ...

  16. Cryptic Sebastes norvegicus species in Greenland waters revealed by microsatellites

    DEFF Research Database (Denmark)

    Saha, Atal; Hauser, Lorenz; Hedeholm, Rasmus

    2017-01-01

    Identification of cryptic species can have profound implications in fishery management, conservation and biodiversity contexts. In the North Atlantic, the genus Sebastes is currently represented by four species, although additional cryptic species have been assumed. The connectivity of the gene...

  17. Genetic factors in Threatened Species Recovery Plans on three continents

    Science.gov (United States)

    Threatened species' recovery planning is applied globally to stem the current species extinction crisis. Evidence supports a key role of genetic processes, such as inbreeding depression, in determining species viability. We examined whether genetic factors are considered in threa...

  18. Variation in biofouling on different species of Indian timbers

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Wagh, A.B.

    Biofouling on twenty species of wood exposed in waters of Mormugao Harbour, Goa, India have been presented. Macrofouling biomass varied from species to species. Maximum biomass was recorded on Artocarpus chaplasha (4 kg/m2) and minimum on Hopea...

  19. Hypoxylon species on beech and other broadleaves

    Directory of Open Access Journals (Sweden)

    Milijašević Tanja

    2004-01-01

    Full Text Available Fungi in the genus Hypoxylon cause wood decay and most of them are saprophytes on dead wood or parasites of weakness. The following species in this genus were identified in this study performed at several localities in Serbia and Montenegro: H. deustum, H. fragiforme, H. nummularium, H. multiforme, H. rubiginosum and H. fuscum. Among them the most significant species is H. deustum, the fungus causing root and butt rot of standing beech trees. It was recorded from all coppice and high forests of beech. This paper presents the morphological characteristics of the recorded fungi their range, plant hosts and significance.

  20. Functional biology of sympatric krill species

    DEFF Research Database (Denmark)

    Agersted, Mette Dalgaard; Nielsen, Torkel Gissel

    2016-01-01

    Here we compare the functional biology of the sympatric krill species, Meganyctiphanes norvegica and Thysanoessa inermis. For M. norvegica, we investigated functional responses on diatoms and copepods, together with prey size spectra on plankton ,400 mm and copepods in the size range 500–3220 mm....... For T. inermis, only prey size spectrum on plankton ,400 mm were investigated. The prey size ranges of both species include organisms ,400 mm, and they consequently graze on several trophic levels. However, T. inermis feed on cells ,10 mm equivalent spherical diameter (ESD), whereas M. norvegica only...

  1. Molecular activation analysis for chemical species studies

    International Nuclear Information System (INIS)

    Chai Zhifang; Mao Xueying; Wang Yuqi; Sun Jingxin; Qian Qingfang; Hou Xiaolin; Zhang Peiqun; Chen Chunying; Feng Weiyu; Ding Wenjun; Li Xiaolin; Li Chunsheng; Dai Xiongxin

    2001-01-01

    The Molecular Activation Analysis (MAA) mainly refers to an activation analysis method that is able to provide information about the chemical species of elements in systems of interest, though its exact definition has remained to be assigned. Its development is strongly stimulated by the urgent need to know the chemical species of elements, because the bulk contents or concentrations are often insignificant for judging biological, environmental or geochemical effects of elements. In this paper, the features, methodology and limitation of MAA were outlined. Further, the up-to-date MAA progress made in our laboratory was introduced as well. (author)

  2. A new dimension in documenting new species

    DEFF Research Database (Denmark)

    Akkari, Nesrine; Enghoff, Henrik; Metscher, Brian D.

    2015-01-01

    We review the state-of-the-art approaches currently applied in myriapod taxonomy, and we describe, for the first time, a new species of millipede (Ommatoiulus avatar n. sp., family Julidae) using high-resolution X-ray microtomography (microCT) as a substantive adjunct to traditional morphological...... examination. We present 3D models of the holotype and paratype specimens and discuss the potential of this non-destructive technique in documenting new species of millipedes and other organisms. The microCT data have been uploaded to an open repository (Dryad) to serve as the first actual millipede cybertypes...

  3. A new alamellate Hygrocybe species from Ecuador

    DEFF Research Database (Denmark)

    Læssøe, Thomas; Boertmann, David

    2008-01-01

    The first known species of Hygrocybe with a smooth hymenophore is described based on material from the eastern slopes of Andean Ecuador. It is considered as incertae sedis in the genus due to a lack of conclusive morphological characters and in the absence of sequence data.......The first known species of Hygrocybe with a smooth hymenophore is described based on material from the eastern slopes of Andean Ecuador. It is considered as incertae sedis in the genus due to a lack of conclusive morphological characters and in the absence of sequence data....

  4. FEATURES DIGESTION OF STURGEON SPECIES (ACIPENSERIDAE (REVIEW

    Directory of Open Access Journals (Sweden)

    M. Simon

    2016-09-01

    Full Text Available Purpose. To review scientific sources are about the anatomical, physiological and biochemical characteristics of the digestive system and proper digestion process in the sturgeon species (Acipenseridae. Outline the common anatomical and morphological characteristics of the gastrointestinal tract. Consider the activity of digestive enzymes and the influence of various factors. Findings. Review of scientific papers reveals that although the digestion of sturgeon are broadly similar to those of the cartilaginous and bony fish, there are a number of species specificity. In particular, sturgeon enzymes have a wider temperature and hydrogen ranges. It is confirmed that temperature adaptations of digestive system poikilothermic organ-isms are realised mainly thanks to reorganisations of fermental systems. It is shown that enzymes in sturgeons are adjustable, as their activity level significantly changes under the influence of divalent metal ions (Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+. The assumption that evolutionary adaptation of hydrolytic function of intestines of fishes to temperature conditions of an inhabitancy takes place, apparently, is made. The paper describes the effect of sex and age factors on the level of activity of enzymes of sturgeons. Set out the regularities of circadian rhythms of the fish of this family. Showed specific features of the liver and its involvement in lipid metabolism and antioxidant defense system. Practical value. The knowledge of hydrolysis characteristics of a diet of sturgeon species is important for the efficiency estimation of feeding and understanding of evolutionary and ecological aspects of digestion physiology. Systematized data on the digestive system of fish sturgeon species are of interest a wide range of research in two main areas. Firstly, although the sturgeon are relict species, but the adaptation of their digestive system is still going on, allowing you to analyze the evolutionary development of the

  5. Big data of tree species distributions

    DEFF Research Database (Denmark)

    Serra-Diaz, Josep M.; Enquist, Brian J.; Maitner, Brian

    2018-01-01

    are currently available in big databases, several challenges hamper their use, notably geolocation problems and taxonomic uncertainty. Further, we lack a complete picture of the data coverage and quality assessment for open/public databases of tree occurrences. Methods: We combined data from five major...... and data aggregation, especially from national forest inventory programs, to improve the current publicly available data.......Background: Trees play crucial roles in the biosphere and societies worldwide, with a total of 60,065 tree species currently identified. Increasingly, a large amount of data on tree species occurrences is being generated worldwide: from inventories to pressed plants. While many of these data...

  6. 77 FR 15701 - Highly Migratory Species; 2006 Consolidated Highly Migratory Species Fishery Management Plan...

    Science.gov (United States)

    2012-03-16

    ... Species Fishery Management Plan; Amendment 4 AGENCY: National Marine Fisheries Service (NMFS), National.... SUMMARY: This fishery management plan (FMP) amendment addresses Atlantic highly migratory species (HMS... to create an HMS Caribbean Small Boat Commercial Permit (CSBP) allowing fishing for and sales of...

  7. Invasive Species Science Branch: research and management tools for controlling invasive species

    Science.gov (United States)

    Reed, Robert N.; Walters, Katie D.

    2015-01-01

    Invasive, nonnative species of plants, animals, and disease organisms adversely affect the ecosystems they enter. Like “biological wildfires,” they can quickly spread and affect nearly all terrestrial and aquatic ecosystems. Invasive species have become one of the greatest environmental challenges of the 21st century in economic, environmental, and human health costs, with an estimated effect in the United States of more than $120 billion per year. Managers of the Department of the Interior and other public and private lands often rank invasive species as their top resource management problem. The Invasive Species Science Branch of the Fort Collins Science Center provides research and technical assistance relating to management concerns for invasive species, including understanding how these species are introduced, identifying areas vulnerable to invasion, forecasting invasions, and developing control methods. To disseminate this information, branch scientists are developing platforms to share invasive species information with DOI cooperators, other agency partners, and the public. From these and other data, branch scientists are constructing models to understand and predict invasive species distributions for more effective management. The branch also has extensive herpetological and population biology expertise that is applied to harmful reptile invaders such as the Brown Treesnake on Guam and Burmese Python in Florida.

  8. Species composition of a soil invertebrate multi-species test system determines the level of ecotoxicity

    DEFF Research Database (Denmark)

    Sechi, Valentina; D'Annibale, Alessandra; Maraldo, Kristine

    2014-01-01

    A soil multi-species, SMS, experimental test system consisting of the natural microbial community, five collembolan species and a predatory mite along with either Enchytraeus crypticus or the earthworm Eisenia fetida were exposed to α-cypermethrin. A comparison of the performance of these two typ...

  9. The Quercus feeding Stigmella species of the West Palaearctic: new species, key and distribution (Lepidoptera: Nepticulidae)

    NARCIS (Netherlands)

    Nieukerken, van E.J.; Johansson, R.

    2003-01-01

    The species of the Stigmella ruficapitella group occurring in the Western Palaearctic and feeding on Quercus are reviewed. We recognise 19 species, five of which are described as new: Stigmella fasciata sp. n. on Quercus pubescens from Slovenia, Croatia, Greece and Turkey, S. cocciferae sp. n. on Q.

  10. Usefulness of the wildlife species as a focal species in the forest ...

    African Journals Online (AJOL)

    yasinucarlı

    2011-03-14

    Mar 14, 2011 ... keystone species are the most important species in that ecosystems to sustainability. ... bear, Wolf and Eurasian Lynx can be also used as a flagship, indicator and ... Washington's Pacific coast. ... sidered keystones because their effect is not dispro- ..... conservation of South American terrestrial mammals.

  11. A new Amazonian species from the Drosophila annulimana species group (Diptera, Drosophilidae

    Directory of Open Access Journals (Sweden)

    Marco S. Gottschalk

    2012-12-01

    Full Text Available Drosophila caxiuana sp. nov., Drosophila subgenus, is described and illustrated. This new species was collected in the Amazonian Biome (Caquajó river, Portel, Pará, Brazil and is an atypical species to the group due the unusual morphology of the male terminalia.

  12. A Framework for Spatial Risk Assessments: Potential Impacts of Nonindigenous Invasive Species on Native Species

    Directory of Open Access Journals (Sweden)

    Craig R. Allen

    2006-06-01

    Full Text Available Many populations of wild animals and plants are declining and face increasing threats from habitat fragmentation and loss as well as exposure to stressors ranging from toxicants to diseases to invasive nonindigenous species. We describe and demonstrate a spatially explicit ecological risk assessment that allows for the incorporation of a broad array of information that may influence the distribution of an invasive species, toxicants, or other stressors, and the incorporation of landscape variables that may influence the spread of a species or substances. The first step in our analyses is to develop species models and quantify spatial overlap between stressor and target organisms. Risk is assessed as the product of spatial overlap and a hazard index based on target species vulnerabilities to the stressor of interest. We illustrate our methods with an example in which the stressor is the ecologically destructive nonindigenous ant, Solenopsis invicta, and the targets are two declining vertebrate species in the state of South Carolina, USA. A risk approach that focuses on landscapes and that is explicitly spatial is of particular relevance as remaining undeveloped lands become increasingly uncommon and isolated and more important in the management and recovery of species and ecological systems. Effective ecosystem management includes the control of multiple stressors, including invasive species with large impacts, understanding where those impacts may be the most severe, and implementing management strategies to reduce impacts.

  13. 78 FR 65974 - Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast...

    Science.gov (United States)

    2013-11-04

    ... Management Councils, the 18 states in the Atlantic and Gulf of Mexico, both the U.S. Virgin Islands and... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XC935 Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast Data, Assessment...

  14. 76 FR 65700 - Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast...

    Science.gov (United States)

    2011-10-24

    .... Virgin Islands and Puerto Rico, and each of the constituent interstate commissions: the Atlantic States... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA776 Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast Data, Assessment...

  15. 77 FR 59842 - Atlantic Highly Migratory Species; 2006 Consolidated Highly Migratory Species Fishery Management...

    Science.gov (United States)

    2012-10-01

    ... vessels permitted in the Atlantic tunas General category in Puerto Rico and 10 in the U.S. Virgin Islands... [Docket No. 080603729-2454-02] RIN 0648-AW83 Atlantic Highly Migratory Species; 2006 Consolidated Highly... management plan (FMP) amendment addresses Atlantic highly migratory species (HMS) fishery management measures...

  16. 77 FR 19164 - Atlantic Highly Migratory Species; 2006 Consolidated Highly Migratory Species Fishery Management...

    Science.gov (United States)

    2012-03-30

    ... RIN 0648-XB121 Atlantic Highly Migratory Species; 2006 Consolidated Highly Migratory Species Fishery..., United States Virgin Islands (USVI) St. Thomas, USVI, San Juan, Puerto Rico (PR), Ponce, PR, and Mayaguez... INFORMATION CONTACT: Greg Fairclough or Randy Blankinship at 727-824-5399. SUPPLEMENTARY INFORMATION: Atlantic...

  17. Multilocus phylogeny and coalescent species delimitation in Kotschy's gecko, Mediodactylus kotschyi: Hidden diversity and cryptic species

    Czech Academy of Sciences Publication Activity Database

    Kotsakiozi, P.; Jablonski, D.; Ilgaz, Ç.; Kumlutaş, Y.; Avci, A.; Meiri, S.; Itescu, Y.; Kukushkin, O.; Gvoždík, Václav; Scillitani, G.; Roussos, S. A.; Jandzik, D.; Kasapidis, P.; Lymberakis, P.; Poulakakis, N.

    2018-01-01

    Roč. 125, August (2018), s. 177-187 ISSN 1055-7903 Institutional support: RVO:68081766 Keywords : Gekkonidae * Divergence times * Species delimitation * Species complex * Systematics * Eastern Mediterranean Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 4.419, year: 2016

  18. Setting maximum sustainable yield targets when yield of one species affects that of other species

    DEFF Research Database (Denmark)

    Rindorf, Anna; Reid, David; Mackinson, Steve

    2012-01-01

    species. But how should we prioritize and identify most appropriate targets? Do we prefer to maximize by focusing on total yield in biomass across species, or are other measures targeting maximization of profits or preserving high living qualities more relevant? And how do we ensure that targets remain...

  19. The Scirtothrips perseae species-group (Thysanoptera), with one new species from avocado, Persea americana.

    Science.gov (United States)

    Mound, Laurence A; Hoddle, Mark S

    2016-02-12

    Following recent molecular studies on avocado thrips, a new species is described from Costa Rica, Ecuador, and Colombia from the young leaves of avocado, Persea americana. Scirtothrips hansoni sp.n. is closely related to the Californian pest, S. perseae, and also to S. astrictus from Costa Rica that remains known from a single female. An illustrated key to these three species is provided.

  20. Species composition and abundance of Brevipalpus spp. on different citrus species in Mexican orchards.

    Science.gov (United States)

    Salinas-Vargas, D; Santillán-Galicia, M T; Valdez-Carrasco, J; Mora-Aguilera, G; Atanacio-Serrano, Y; Romero-Pescador, P

    2013-08-01

    We studied the abundance of Brevipalpus spp. in citrus orchards in the Mexican states of Yucatan, Quintana Roo and Campeche. Mites were collected from 100 trees containing a mixture of citrus species where sweet orange was always the main species. Eight collections were made at each location from February 2010 to February 2011. Mites from the genus Brevipalpus were separated from other mites surveyed and their abundance and relationships with the different citrus species were quantified throughout the collection period. A subsample of 25% of the total Brevipalpus mites collected were identified to species level and the interaction of mite species and citrus species were described. Brevipalpus spp. were present on all collection dates and their relative abundance was similar on all citrus species studies. The smallest number of mites collected was during the rainy season. Brevipalpus phoenicis (Geijskes) and Brevipalpus californicus (Banks) were the only two species present and they were found in all locations except Campeche, where only B. phoenicis was present. Yucatan and Campeche are at greater risk of leprosis virus transmission than Quintana Roo because the main vector, B. phoenicis, was more abundant than B. californicus. The implications of our results for the design of more accurate sampling and control methods for Brevipalpus spp. are discussed.

  1. Evaluation of a multiple-species approach to monitoring species at the ecoregional scale

    Science.gov (United States)

    Patricia N. Manley; William J. Zielinski; Matthew D. Schlesinger; Sylvia R. Mori

    2004-01-01

    Monitoring is required of land managers and conservation practitioners to assess the success of management actions. "Shortcuts" are sought to reduce monitoring costs, most often consisting of the selection of a small number of species that are closely monitored to represent the status of many associated species and environmental correlates. Assumptions...

  2. Species status and conservation issues of New Zealand's endemic Latrodectus spider species (Araneae: Theridiidae)

    DEFF Research Database (Denmark)

    Vink, Cor J; Sirvid, Phillip J; Malumbres-Olarte, Jagoba

    2008-01-01

    New Zealand has two endemic widow spiders, Latrodectus katipo Powell, 1871 and L. atritus Urquhart, 1890. Both species face many conservation threats and are actively managed. The species status of the Latrodectus spiders of New Zealand was assessed using molecular (COI, ITS1, ITS2...

  3. Preliminary data on Saga pedo – specific habitats

    Directory of Open Access Journals (Sweden)

    LUPU N. Gabriel

    2007-10-01

    Full Text Available Due to its exceptional size (from 53 to 75 mm of body to which one adds an oviscapte approximately 35 mm Saga pedo is considered one off the largest insect of Europe. Its exclusively carnivorous diet and parthenogenetic reproduction makes it an exceptional insect. The present paper gives an overview on the habitats from northern Dobrogea where this species occurs.

  4. Toxicity testing with the collembolans Folsomia fimetaria and Folsomia candida and the results of a ringtest

    DEFF Research Database (Denmark)

    Krogh, Paul Henning

    A ringtest was performed to introduce collembolans for the OECD test guideline programme. One species, the parthenogenetic Folsomia candida, is already an approved ISO standard while the sexually reproducing Folsomia fimetaria is introduced in the draft test guideline as an alternative to F. cand...

  5. New Species of Calamus (Palmae from Lao and Myanmar

    Directory of Open Access Journals (Sweden)

    Andrew Henderson

    2007-06-01

    Full Text Available This paper concerns southern Asian species of Calamus from Beccari’s Groups V and VI. Calamus floribundus var. depauperatus is recognized as a distinct species, C. meghalayensis; C. kingianus is recognized as a distinct species from northeastern India and the Lao population of C. kingianus is recognized as a separate species, C. evansii; recently collected specimens from northern Myanmar are recognized as two distinct species, C. hukaungensis and C. spicatus; C. hypoleucus is recognized as a distinct species from Myanmar and the Lao population of C. hypoleucus is recognized as a distinct species, C minor. Nomenclature, descriptions, illustrations, specimens examined, and distribution maps are given for the new species.

  6. Valuing local endangered species. The role of intra-species substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Maria L. [Department of Economic Analysis, Universidade de Santiago (Spain); IDEGA, Universidade de Santiago de Compostela, Campus Sur, Avda das Ciencias, S/N. 15782, Santiago de Compostela (Spain); Ojea, Elena [IDEGA, Universidade de Santiago de Compostela, Campus Sur, Avda das Ciencias, S/N. 15782, Santiago de Compostela (Spain)

    2008-12-01

    Valuation of endangered species is important in many circumstances, and particularly when assessing the impact of large accidental oil spills. Previous studies have tested the effects of including in the contingent valuation survey reminders about the existence of diverse substitutes (in terms of other natural resources also in danger of extinction in the same area, other programs to be valued, or alternative uses of money). We include a reminder about the existence of the same biological species not being under danger of extinction elsewhere. We believe this reminder allows individuals to make an easy assessment of the biological scarcity of the species they are supposed to value. Thus, the key difference with previous studies is that valuation of endangered species is combined with an assessment of preferences towards conservation of local and native species. Our WTP results are not sensitive to the information provided about other foreign substitutes. Implications of this finding are discussed. (author)

  7. Valuing local endangered species. The role of intra-species substitutes

    International Nuclear Information System (INIS)

    Loureiro, Maria L.; Ojea, Elena

    2008-01-01

    Valuation of endangered species is important in many circumstances, and particularly when assessing the impact of large accidental oil spills. Previous studies have tested the effects of including in the contingent valuation survey reminders about the existence of diverse substitutes (in terms of other natural resources also in danger of extinction in the same area, other programs to be valued, or alternative uses of money). We include a reminder about the existence of the same biological species not being under danger of extinction elsewhere. We believe this reminder allows individuals to make an easy assessment of the biological scarcity of the species they are supposed to value. Thus, the key difference with previous studies is that valuation of endangered species is combined with an assessment of preferences towards conservation of local and native species. Our WTP results are not sensitive to the information provided about other foreign substitutes. Implications of this finding are discussed. (author)

  8. Cross-species amplification of microsatellite loci developed for Passiflora edulis Sims. in related Passiflora Species

    Directory of Open Access Journals (Sweden)

    Gilmara Alvarenga Fachardo Oliveira

    2013-10-01

    Full Text Available The aim of this study was to evaluate the selected 41 SSR markers developed for yellow passion fruit (Passiflora edulis f. flavicarpa Sims. for their transferability to 11 different Passiflora species. Twenty-one SSR were successfully amplified in 10 wild species of passion fruit producing 101 bands. All the markers were amplifiable for at least one species. The mean transferability was 68,8%, ranging from 15,4% (primer PE11 to 100 % (PE13, PE18, PE37, PE41 and PE88. Transferability was higher for the species from the Passiflora subgenus than for those from the Decaloba and Dysosmia subgenus. The results indicated a high level of nucleotide sequence conservation of the primer regions in the species evaluated, and consequently, they could potentially be used for the establishment of molecular strategies for use in passion fruit breeding and genetics.

  9. SESAM – a new framework integrating macroecological and species distribution models for predicting spatio-temporal patterns of species assemblages

    DEFF Research Database (Denmark)

    Guisan, Antoine; Rahbek, Carsten

    2011-01-01

    Two different approaches currently prevail for predicting spatial patterns of species assemblages. The first approach (macroecological modelling, MEM) focuses directly on realized properties of species assemblages, whereas the second approach (stacked species distribution modelling, S-SDM) starts...

  10. Cryptic Species Due to Hybridization: A Combined Approach to Describe a New Species (Carex: Cyperaceae).

    Science.gov (United States)

    Maguilla, Enrique; Escudero, Marcial

    2016-01-01

    Disappearance of diagnostic morphological characters due to hybridization is considered to be one of the causes of the complex taxonomy of the species-rich (ca. 2000 described species) genus Carex (Cyperaceae). Carex furva s.l. belongs to section Glareosae. It is an endemic species from the high mountains of the Iberian Peninsula (Spain and Portugal). Previous studies suggested the existence of two different, cryptic taxa within C. furva s.l. Intermediate morphologies found in the southern Iberian Peninsula precluded the description of a new taxa. We aimed to determine whether C. furva s.l. should be split into two different species based on the combination of morphological and molecular data. We sampled ten populations across its full range and performed a morphological study based on measurements on herbarium specimens and silica-dried inflorescences. Both morphological and phylogenetic data support the existence of two different species within C. furva s.l. Nevertheless, intermediate morphologies and sterile specimens were found in one of the southern populations (Sierra Nevada) of C. furva s.l., suggesting the presence of hybrid populations in areas where both supposed species coexist. Hybridization between these two putative species has blurred morphological and genetic limits among them in this hybrid zone. We have proved the utility of combining molecular and morphological data to discover a new cryptic species in a scenario of hybridization. We now recognize a new species, C. lucennoiberica, endemic to the Iberian Peninsula (Sierra Nevada, Central system and Cantabrian Mountains). On the other hand, C. furva s.s. is distributed only in Sierra Nevada, where it may be threatened by hybridization with C. lucennoiberica. The restricted distribution of both species and their specific habitat requirements are the main limiting factors for their conservation.

  11. INVENTORY OF THE INVASIVE ALIE N PLANT SPECIES IN INDONESIA

    Directory of Open Access Journals (Sweden)

    SRI S UDARMIYATI T JITROSOEDIRDJO

    2005-01-01

    Full Text Available An inventory of the alien plant species in Indone sia based on the existing references and herbarium specimens concluded that 1936 alien plant species ar e found in Indonesia which belong to 187 families. Field studies should be done to get the complete figur es of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be iden tified, followed by studies on the assessment of losses, biology, management and their possible utilizations. Alien plant species are imported to Indonesia for cultivation, collection of the botanical garden, as experimental plants or other curiosities. Aside from plants purposely imported, there are also introduced plant propagules conta-minating imported agricultural products. These alien plant species can be beneficial or have a potential of being invasive. The alien cultivated species consisted of 67% of the total number. More than half of the cultivated plants are ornamental plants. Some of th e species are naturalized or escaped from cultivation and become wild and invasive. Some other natura lized species, adapted well without any problems of invasion. There are 339 species or 17% of the species r ecorded as weeds. The highest record of weeds is found in the family of Poaceae (57 species, follo wed by Asteraceae (53 species and Cyperaceae (35 species. There are 6 families having more than 10 species of weeds: Amaranthaceae, Asteraceae, Cyperaceae, Euphorbiaceae, Poaceae, and Rubiaceae. Three families have more than 100 species: Asteraceae 162 species, Poaceae 120 species, and Papillionaceae 103 species. Five species of aquatic and 20 species of terrestrial plants considered as important alien plant species in Indonesia were identified and some of their distributions noted

  12. Are Humans the Most Intelligent Species?

    Directory of Open Access Journals (Sweden)

    Robert P. Erickson

    2014-09-01

    Full Text Available Hunt and Jaeggi [1] nicely summarize the point that within the academic field of intelligence, we do not have a commonly understandable definition of what intelligence is. Still the term is used extensively and with consensus to the effect that humans are the most intelligent species. An example is given of this problem, and a definition and solution are suggested.

  13. Molecular species identification and population genetics of ...

    African Journals Online (AJOL)

    Molecular genetic techniques, such as DNA barcoding and genotyping, are increasingly being used to assist with the conservation and management of chondrichthyans worldwide. Southern Africa is a shark biodiversity hotspot, with a large number of endemic species. According to the IUCN Red List, a quarter of South ...

  14. Evaluation of two okra species [Abelmoschusesculentus (L ...

    African Journals Online (AJOL)

    DizMat_Ogwu

    2014-02-26

    Feb 26, 2014 ... African Journal of Biotechnology. Full Length Research Paper. Evaluation of two okra species ..... Amakiri JO, Onofeghara FA (1984). Effect of crude oil pollution on the growth of Zea mays, Abelmoschusesculentusand capsicum frutescans. Oil Pet. Pollut. 1:199-206. Ariyo OJ (1993). Genetic diversity in west ...

  15. Population dynamics of Pseudo-nitzschia species ...

    African Journals Online (AJOL)

    The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es Salaam. Samples ...

  16. A new Species of Spadella (Benthic Chaetognatha)

    NARCIS (Netherlands)

    Alvariño, Angeles

    1970-01-01

    According to the literature, the genus Spadella Langerhans includes several species, Sp. cephaloptera (Busch) 1851, Sp. schizoptera Conant 1895, Sp. moretonensis Johnston & Taylor 1919, Sp. sheardi Mawson 1944, Sp. johnstoni Mawson 1944, Sp. angulata Tokioka 1951, Sp. nana Owre 1963, Sp. pulchella

  17. Is Echinococcus intermedius a valid species?

    Science.gov (United States)

    Medical and veterinary sciences require scientific names to discriminate pathogenic organisms in our living environment. Various species concepts have been proposed for metazoan animals. There are, however, constant controversies over their validity because of lack of a common criterion to define ...

  18. Geographic distribution of wild potato species

    NARCIS (Netherlands)

    Hijmans, R.J.; Spooner, D.M.

    2001-01-01

    The geographic distribution of wild potatoes (Solanaceae sect. Petota) was analyzed using a database of 6073 georeferenced observations. Wild potatoes occur in 16 countries, but 88% of the observations are from Argentina, Bolivia, Mexico, and Peru. Most species are rare and narrowly endemic: for 77

  19. Invasive species in southern Nevada [Chapter 4

    Science.gov (United States)

    Mathew L. Brooks; Steven M. Ostoja; Jeanne C. Chambers

    2013-01-01

    Southern Nevada contains a wide range of topographies, elevations, and climatic zones emblematic of its position at the ecotone between the Mojave Desert, Great Basin, and Colorado Plateau ecoregions. These varied environmental conditions support a high degree of biological diversity (Chapter 1), but they also provide opportunities for a wide range of invasive species...

  20. Spatial patterns of species diversity in Kenya

    NARCIS (Netherlands)

    Oindo, B.O.

    2001-01-01

    The most striking feature of Earth is the existence of life and the most striking feature of life is its diversity. Explaining patterns of species diversity is one of the most complex problems in ecology. This is because diversity is usually the outcome of many contributing factors whose relative

  1. Mannheimia Species Associated with Ovine Mastitis▿

    OpenAIRE

    Omaleki, Lida; Barber, Stuart R.; Allen, Joanne L.; Browning, Glenn F.

    2010-01-01

    Mannheimia glucosida, M. haemolytica, and M. ruminalis were isolated from cases of acute mastitis in ewes. M. glucosida was found to be a common cause of clinical mastitis in sheep. Selected phenotypic tests in addition to genotyping were needed to definitively identify Mannheimia species causing ovine mastitis.

  2. Antibacterial potential components of Bacillus species and ...

    African Journals Online (AJOL)

    Honey is a sweet viscous liquid produced by honey bee, Apis mellifera from the nectar of plants. Honey is a natural product that has been used from ancient times till now as food and for medicinal purpose. This study was carried out to determine the mode of action of Bacillus species and antibiotics residues in branded and ...

  3. Environmental Politics and the Endangered Species Act.

    Science.gov (United States)

    Sahr, David

    2000-01-01

    Explores the controversial issue of the Endangered Species Act (ESA) discussing the Act and the scope of the extinction problem. Reviews the arguments for and against the ESA, addresses the tactics that have been used in the political struggle over the ESA, and highlights the future of the ESA. Includes teaching activities. (CMK)

  4. Darwin's Book: On the Origin of Species

    Science.gov (United States)

    Hodge, Jonathan

    2013-09-01

    This essay is an interpretation of Charles Darwin's Origin of Species. It focuses on the contents of the Origin as Darwin intended them to be understood and the background to the work, thus revealing the originality (or otherwise) of the work.

  5. Biodiversity and the exotic species threat

    Science.gov (United States)

    Peter S. White

    1998-01-01

    Exotic species invasions, called by one conservation biologist the "least reversible" of all human impacts, cause harm to economies (e.g., fisheries, wildlife populations, tourism), the environment (e.g., in the form of broadcast of pesticides and herbicides), human health and wellbeing (e.g., allergic responses and the increase in fire severity in some...

  6. Unparalleled rates of species diversification in Europe

    Science.gov (United States)

    Valente, Luis M.; Savolainen, Vincent; Vargas, Pablo

    2010-01-01

    The most rapid species radiations have been reported from ‘evolutionary laboratories’, such as the Andes and the Cape of South Africa, leading to the prevailing view that diversification elsewhere has not been as dramatic. However, few studies have explicitly assessed rates of diversification in northern regions such as Europe. Here, we show that carnations (Dianthus, Caryophyllaceae), a well-known group of plants from temperate Eurasia, have diversified at the most rapid rate ever reported in plants or terrestrial vertebrates. Using phylogenetic methods, we found that the majority of species of carnations belong to a lineage that is remarkably species-rich in Europe, and arose at the rate of 2.2–7.6 species per million years. Unlike most previous studies that have inferred rates of diversification in young diverse groups, we use a conservative approach throughout that explicitly incorporates the uncertainties associated with phylogenetic inference, molecular dating and incomplete taxon sampling. We detected a shift in diversification rates of carnations coinciding with a period of increase in climatic aridity in the Pleistocene, suggesting a link between climate and biodiversity. This explosive radiation suggests that Europe, the continent with the world's best-studied flora, has been underestimated as a cradle of recent and rapid speciation. PMID:20106850

  7. Alien invasive species and international trade

    Science.gov (United States)

    Emergency control measures for invasive species often rely on use of pesticides and other destructive practices. Public concern about pesticide contamination of the ground water and the environment has lead to increased restrictions on the use of pesticides for control of many destructive invasive ...

  8. (OLIGOCHAETA) FROM SOUTH AFRICAN RIVERS Two species

    African Journals Online (AJOL)

    portion and may be regarded as a chamber of the ampulla, though its walls may be con- voluted. The duct ..... fall within known variation for the species: dimensions, number of segments, form of the ...... 01igochaeta in Das Tierrich, 10, Berlin.

  9. Some new Australasian species of Xyris

    NARCIS (Netherlands)

    Royen, van P.

    1954-01-01

    During the study of the Xyridaceae of the Malaysian area it was desirable to study those of Australia and Continental Asia as well. The Malaysian species now have, in the meantime, been published (Flora Malesiana, ser. 1, 4, 1953, 366—376). To the new taxa described in Blumea 7, 1953, 307—308 the

  10. On the Origins of a Vibrio species

    DEFF Research Database (Denmark)

    Vesth, Tammi Camilla; Wassenaar, Gertrude Maria; Hallin, Peter Fischer

    2010-01-01

    Thirty-two genome sequences of various Vibrionaceae members are compared, with emphasis on what makes V. cholerae unique. As few as 1,000 gene families are conserved across all the Vibrionaceae genomes analysed; this fraction roughly doubles for gene families conserved within the species V. chole...

  11. Karyotype of some Thai Hypoxidaceae species

    Directory of Open Access Journals (Sweden)

    Ladda Eksomtramage

    2013-08-01

    Full Text Available Somatic chromosome numbers and karyotypes of nine species in three genera of Thai Hypoxidaceae were determinedin root tips. All species are diploid with 2n = 18 and asymmetrical karyotypes including metacentric (m submetacentric (smsubtelocentric (st and also telocentric (t in some species. Satellite chromosomes (SAT were observed in all species studiedexcept in C. latifolia. The karyotypes of Curculigo ensifolia 4m+8sm+6st(2SAT, C. latifolia 2m+14sm+2st, C. megacarpa2m+12sm+4st(2SAT, C. villosa 4m+10sm(2SAT+4st, Hypoxis aurea 2m+8sm+8st(2SAT, Molineria capitulata 2m+10sm+2st (2SAT+4t, M. trichocarpa 2m+10sm+6st(2SAT, M. gracilis and M. latifolia 4m+8sm+4st (2SAT+2t are reported forthe first time. The chromosome relative length of Curculigo, Hypoxis and Molineria range between 3.44-9.55, 4.03-8.12 and3.64-8.97, respectively.

  12. Immunological detection of Fusarium species in cornmeal.

    Science.gov (United States)

    Iyer, M S; Cousin, M A

    2003-03-01

    An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect Fusarium species in foods. Antibodies to proteins extracted from the mycelia of Fusarium graminearum and Fusarium moniliforme (verticillioides) were produced in New Zealand white rabbits. These antibodies detected 13 Fusarium species in addition to the producer strains. Levels of Fusarium semitectum and Fusarium tricinctum strains were below the detection threshold. The specificity of the assay was tested against 70 molds and yeasts belonging to 23 genera. One strain of Monascus species and one strain of Phoma exigua were detected; however, these two molds are not common contaminants of cereal grains or foods and should not interfere with the assay. The indirect ELISA's detection limits for F. graminearum and F. moniliforme were 0.1 and 1 microg of mold mycelium per ml of a cornmeal mixture, respectively. When spores of each mold were added individually to cornmeal mixtures (at ca. 10 spores per g) and incubated at 25 degrees C, these spores were detected by the indirect ELISA when they reached levels of 10(2) to 10(3) CFU/ml after 24 to 36 h. The indirect ELISA developed here shows promise for the detection of Fusarium species in grains or foods.

  13. The South African species of Teucrium (Lamiaceae

    Directory of Open Access Journals (Sweden)

    L. E. Codd

    1977-11-01

    Full Text Available While writing up the three South African species of  Teucrium for the Flora o f Southern Africa it became necessary to replace two well-known names as follows:  T. trifidum Retz. (1779 ( = T.  capense Thunb., 1800 and  T. kraussii Codd  {=T. riparium Hochst., 1845, non Rafin., 1838.

  14. Island Species Richness Increases with Habitat Diversity

    NARCIS (Netherlands)

    Hortal, J.; Triantis, K.A.; Meiri, S.; Thebault, E.M.C.; Sfenthourakis, S.

    2009-01-01

    Species richness is commonly thought to increase with habitat diversity. However, a recent theoretical model aiming to unify niche and island biogeography theories predicted a hump-shaped relationship between richness and habitat diversity. Given the contradiction between model results and previous

  15. Self-thinning in four pine species

    NARCIS (Netherlands)

    Brunet-Navarro, Pau; Sterck, Frank J.; Vayreda, Jordi; Martinez-Vilalta, Jordi; Mohren, Frits

    2016-01-01

    Key message: Self-thinning lines are species- and climate-specific, and they should be used when assessing the capacity of different forest stands to increase biomass/carbon storage. Context: The capacity of forests to store carbon can help to mitigate the effects of atmospheric CO2

  16. Reserve design to maximize species persistence

    Science.gov (United States)

    Robert G. Haight; Laurel E. Travis

    2008-01-01

    We develop a reserve design strategy to maximize the probability of species persistence predicted by a stochastic, individual-based, metapopulation model. Because the population model does not fit exact optimization procedures, our strategy involves deriving promising solutions from theory, obtaining promising solutions from a simulation optimization heuristic, and...

  17. Vanishing Species: The Planet in Crisis

    Indian Academy of Sciences (India)

    Permanent link: https://www.ias.ac.in/article/fulltext/reso/015/04/0321-0336. Keywords. Species; mass extinction; biotic crisis; hotspot. Author Affiliations. Uttam Saikia1 Narayan Sharma Abhijit Das. High Altitude Zoology Field Station, Zoological Survey of India, Saproon, Solan, H.P.173211. Resonance – Journal of Science ...

  18. Radiocaesium accumulation by different plant species

    International Nuclear Information System (INIS)

    Filiptsova, G.G.

    2000-01-01

    Using the model object influence of mineral nutritions level on radiocaesium accumulation by different plant species has been studied. It was shown the wheat roots accumulation the minimal value on radiocaesium on normal potassium level, the rye roots accumulation maximal level radiocaesium. (authors)

  19. Species status of Mill Creek Elliptio

    Energy Technology Data Exchange (ETDEWEB)

    Davis, G.M. [Academy of Natural Sciences (United States); Mulvey, M. [Savannah River Ecology Lab., Aiken, SC (United States)

    1993-12-31

    This report discusses environmental effects of the Savannah River Plant on aqautic populations in Mill Creek and surrounding tributaries. Of particular concern was the status of Elliptio. Genetics and phenotypic characteristics have shown that the current classification system is not adequate for these populations. The appendices characterize genetic variability at different loci, electrophoretic data, allele frequencies, sympatric species, and anatomical characters.

  20. Multiple bacterial species reside in chronic wounds

    DEFF Research Database (Denmark)

    Gjødsbøl, Kristine; Christensen, Jens Jørgen; Karlsmark, Tonny

    2006-01-01

    . aeruginosa were found to be significantly larger than ulcers without the presence of P. aeruginosa (P wound is colonised by multiple bacterial species and that once they are established many of them persist in the wound. Our results suggest that the presence...... of P. aeruginosa in venous leg ulcers can induce ulcer enlargement and/or cause delayed healing....