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Sample records for acoel isodiametra pulchra

  1. Characterization of the stem cell system of the acoel Isodiametra pulchra

    PubMed Central

    2009-01-01

    Background Tissue plasticity and a substantial regeneration capacity based on stem cells are the hallmark of several invertebrate groups such as sponges, cnidarians and Platyhelminthes. Traditionally, Acoela were seen as an early branching clade within the Platyhelminthes, but became recently positioned at the base of the Bilateria. However, little is known on how the stem cell system in this new phylum is organized. In this study, we wanted to examine if Acoela possess a neoblast-like stem cell system that is responsible for development, growth, homeostasis and regeneration. Results We established enduring laboratory cultures of the acoel Isodiametra pulchra (Acoela, Acoelomorpha) and implemented in situ hybridization and RNA interference (RNAi) for this species. We used BrdU labelling, morphology, ultrastructure and molecular tools to illuminate the morphology, distribution and plasticity of acoel stem cells under different developmental conditions. We demonstrate that neoblasts are the only proliferating cells which are solely mesodermally located within the organism. By means of in situ hybridisation and protein localisation we could demonstrate that the piwi-like gene ipiwi1 is expressed in testes, ovaries as well as in a subpopulation of somatic stem cells. In addition, we show that germ cell progenitors are present in freshly hatched worms, suggesting an embryonic formation of the germline. We identified a potent stem cell system that is responsible for development, homeostasis, regeneration and regrowth upon starvation. Conclusions We introduce the acoel Isodiametra pulchra as potential new model organism, suitable to address developmental questions in this understudied phylum. We show that neoblasts in I. pulchra are crucial for tissue homeostasis, development and regeneration. Notably, epidermal cells were found to be renewed exclusively from parenchymally located stem cells, a situation known only from rhabditophoran flatworms so far. For further

  2. Mesodermal Gene Expression in the Acoel Isodiametra pulchra Indicates a Low Number of Mesodermal Cell Types and the Endomesodermal Origin of the Gonads

    PubMed Central

    Chiodin, Marta; Børve, Aina; Berezikov, Eugene; Ladurner, Peter; Martinez, Pedro; Hejnol, Andreas

    2013-01-01

    Acoelomorphs are bilaterally symmetric small marine worms that lack a coelom and possess a digestive system with a single opening. Two alternative phylogenetic positions of this group within the animal tree are currently debated. In one view, Acoelomorpha is the sister group to all remaining Bilateria and as such, is a morphologically simple stepping stone in bilaterian evolution. In the other, the group is a lineage within the Deuterostomia, and therefore, has derived a simple morphology from a more complex ancestor. Acoels and the closely related Nemertodermatida and Xenoturbellida, which together form the Acoelomorpha, possess a very limited number of cell types. To further investigate the diversity and origin of mesodermal cell types we describe the expression pattern of 12 orthologs of bilaterian mesodermal markers including Six1/2, Twist, FoxC, GATA4/5/6, in the acoel Isodiametra pulchra. All the genes are expressed in stem cells (neoblasts), gonads, and at least subsets of the acoel musculature. Most are expressed in endomesodermal compartments of I. pulchra developing embryos similar to what has been described in cnidarians. Our molecular evidence indicates a very limited number of mesodermal cell types and suggests an endomesodermal origin of the gonads and the stem cell system. We discuss our results in light of the two prevailing phylogenetic positions of Acoelomorpha. PMID:23405161

  3. Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha)

    PubMed Central

    2013-01-01

    Introduction Regeneration is a widespread phenomenon in the animal kingdom, but the capacity to restore damaged or missing tissue varies greatly between different phyla and even within the same phylum. However, the distantly related Acoelomorpha and Platyhelminthes share a strikingly similar stem-cell system and regenerative capacity. Therefore, comparing the underlying mechanisms in these two phyla paves the way for an increased understanding of the evolution of this developmental process. To date, Isodiametra pulchra is the most promising candidate as a model for the Acoelomorpha, as it reproduces steadily under laboratory conditions and is amenable to various techniques, including the silencing of gene expression by RNAi. In order to provide an essential framework for future studies, we report the succession of regeneration events via the use of cytochemical, histological and microscopy techniques, and specify the total number of cells in adult individuals. Results Isodiametra pulchra is not capable of regenerating a new head, but completely restores all posterior structures within 10 days. Following amputation, the wound closes via the contraction of local muscle fibres and an extension of the dorsal epidermis. Subsequently, stem cells and differentiating cells invade the wound area and form a loosely delimited blastema. After two days, the posterior end is re-patterned with the male (and occasionally the female) genital primordium being apparent. Successively, these primordia differentiate into complete copulatory organs. The size of the body and also of the male and female copulatory organs, as well as the distance between the copulatory organs, progressively increase and by nine days copulation is possible. Adult individuals with an average length of 670 μm consist of approximately 8100 cells. Conclusion Isodiametra pulchra regenerates through a combination of morphallactic and epimorphic processes. Existing structures are “re-modelled” and provide a

  4. The nervous system of Isodiametra pulchra (Acoela) with a discussion on the neuroanatomy of the Xenacoelomorpha and its evolutionary implications

    PubMed Central

    2012-01-01

    Introduction Acoels are microscopic marine worms that have become the focus of renewed debate and research due to their placement at the base of the Bilateria by molecular phylogenies. To date, Isodiametra pulchra is the most promising “model acoel” as it can be cultured and gene knockdown can be performed with double-stranded RNA. Despite its well-known morphology data on the nervous system are scarce. Therefore we examined this organ using various microscopic techniques, including histology, conventional histochemistry, electron microscopy, and immunocytochemistry in combination with CLSM and discuss our results in light of recently established phylogenies. Results The nervous system of Isodiametra pulchra consists of a bilobed brain with a dorsal posterior commissure, a frontal ring and tracts, four pairs of longitudinal neurite bundles, as well as a supramuscular and submuscular plexus. Serotonin-like immunoreactivity (SLI) is displayed in parts of the brain, the longitudinal neurite bundles and a large part of the supramuscular plexus, while FMRFamide-like immunoreactivity (RFLI) is displayed in parts of the brain and a distinct set of neurons, the longitudinal neurite bundles and the submuscular plexus. Despite this overlap SLI and RFLI are never colocalized. Most remarkable though is the presence of a distinct functional neuro-muscular system consisting of the statocyst, tracts, motor neurons and inner muscles, as well as the presence of various muscles that differ with regard to their ultrastructure and innervation. Conclusions The nervous system of Isodiametra pulchra consists of an insunk, bilobed brain, a peripheral part for perception and innervation of the smooth body-wall musculature as well as tracts and motor neurons that together with pseudostriated inner muscles are responsible for steering and quick movements. The insunk, bilobed brains with two to three commissures found in numerous acoels are homologous and evolved from a ring

  5. To be or not to be a flatworm: the acoel controversy.

    PubMed

    Egger, Bernhard; Steinke, Dirk; Tarui, Hiroshi; De Mulder, Katrien; Arendt, Detlev; Borgonie, Gaëtan; Funayama, Noriko; Gschwentner, Robert; Hartenstein, Volker; Hobmayer, Bert; Hooge, Matthew; Hrouda, Martina; Ishida, Sachiko; Kobayashi, Chiyoko; Kuales, Georg; Nishimura, Osamu; Pfister, Daniela; Rieger, Reinhard; Salvenmoser, Willi; Smith, Julian; Technau, Ulrich; Tyler, Seth; Agata, Kiyokazu; Salzburger, Walter; Ladurner, Peter

    2009-01-01

    Since first described, acoels were considered members of the flatworms (Platyhelminthes). However, no clear synapomorphies among the three large flatworm taxa -- the Catenulida, the Acoelomorpha and the Rhabditophora -- have been characterized to date. Molecular phylogenies, on the other hand, commonly positioned acoels separate from other flatworms. Accordingly, our own multi-locus phylogenetic analysis using 43 genes and 23 animal species places the acoel flatworm Isodiametra pulchra at the base of all Bilateria, distant from other flatworms. By contrast, novel data on the distribution and proliferation of stem cells and the specific mode of epidermal replacement constitute a strong synapomorphy for the Acoela plus the major group of flatworms, the Rhabditophora. The expression of a piwi-like gene not only in gonadal, but also in adult somatic stem cells is another unique feature among bilaterians. These two independent stem-cell-related characters put the Acoela into the Platyhelminthes-Lophotrochozoa clade and account for the most parsimonious evolutionary explanation of epidermal cell renewal in the Bilateria. Most available multigene analyses produce conflicting results regarding the position of the acoels in the tree of life. Given these phylogenomic conflicts and the contradiction of developmental and morphological data with phylogenomic results, the monophyly of the phylum Platyhelminthes and the position of the Acoela remain unresolved. By these data, both the inclusion of Acoela within Platyhelminthes, and their separation from flatworms as basal bilaterians are well-supported alternatives.

  6. Acoel flatworms are not platyhelminthes: evidence from phylogenomics.

    PubMed

    Philippe, Hervé; Brinkmann, Henner; Martinez, Pedro; Riutort, Marta; Baguñà, Jaume

    2007-08-08

    Acoel flatworms are small marine worms traditionally considered to belong to the phylum Platyhelminthes. However, molecular phylogenetic analyses suggest that acoels are not members of Platyhelminthes, but are rather extant members of the earliest diverging Bilateria. This result has been called into question, under suspicions of a long branch attraction (LBA) artefact. Here we re-examine this problem through a phylogenomic approach using 68 different protein-coding genes from the acoel Convoluta pulchra and 51 metazoan species belonging to 15 different phyla. We employ a mixture model, named CAT, previously found to overcome LBA artefacts where classical models fail. Our results unequivocally show that acoels are not part of the classically defined Platyhelminthes, making the latter polyphyletic. Moreover, they indicate a deuterostome affinity for acoels, potentially as a sister group to all deuterostomes, to Xenoturbellida, to Ambulacraria, or even to chordates. However, the weak support found for most deuterostome nodes, together with the very fast evolutionary rate of the acoel Convoluta pulchra, call for more data from slowly evolving acoels (or from its sister-group, the Nemertodermatida) to solve this challenging phylogenetic problem.

  7. The unique developmental program of the acoel flatworm, Neochildia fusca.

    PubMed

    Henry, J Q; Martindale, M Q; Boyer, B C

    2000-04-15

    Acoel embryos exhibit a unique form of development that some investigators argue is related to that found in polyclad turbellarians and coelomate spiralians, which display typical quartet spiral cleavage. We generated the first cell-lineage fate map for an acoel flatworm, Neochildia fusca, using modern intracellular lineage tracers to assess the degree of similarity between these distinct developmental programs. N. fusca develops via a "duet" cleavage pattern in which second cleavage occurs in a leiotropically oblique plane relative to the animal-vegetal axis. At the four-cell stage, the plane of first cleavage corresponds to the plane of bilateral symmetry. All remaining cleavages are symmetrical across the sagittal plane. No ectomesoderm is formed; the first three micromere duets generate only ectodermal derivatives. Endomesoderm, including the complex assemblage of circular, longitudinal, and oblique muscle fibers, as well as the peripheral and central parenchyma, is generated by both third duet macromeres. The cleavage pattern, fate map, and origins of mesoderm in N. fusca share little similarity to that exhibited by other spiralians, including the Platyhelminthes (e.g., polyclad turbellarians). These findings are considered in light of the possible evolutionary origins of the acoel duet cleavage program versus the more typical quartet spiral cleavage program. Finally, an understanding of the cell-lineage fate map allows us to interpret the results of earlier cell deletion studies examining the specification of cell fates within these embryos and reveals the existence of cell-cell inductive interactions in these embryos.

  8. Graptemys pulchra Baur 1893: Alabama Map Turtle

    USGS Publications Warehouse

    Lovich, Jeffrey E.; Godwin, James C.; McCoy, C.J.; Rhodin, A. G. J.; Pritchard, P. C. H.; van Dijk, P. P.; Saumure, R.A.; Buhlmann, K.A.; Iverson, J.B.; Mittermeier, R.A.

    2014-01-01

    The Alabama Map Turtle, Graptemys pulchra (Family Emydidae), is a moderately large riverine species endemic to the Mobile Bay drainage system of Alabama, Georgia, and Mississippi. Sexual size dimorphism is pronounced, with adult females (carapace length [CL] to 273 mm) attaining more than twice the size of adult males (CL to 117 mm). The species is an inhabitant of relatively large, swift creeks and rivers, often with wide sandbars. Stream sections open to the sun and with abundant basking sites in the form of logs and brush are preferred. Six to seven clutches of 4–7 eggs are laid each year on river sandbars. Although the species is locally abundant, populations are threatened by habitat destruction, declines in their prey base, commercial collection, and vandalism. It is listed as a Species of Special Concern in Alabama.

  9. Functional brain regeneration in the acoel worm Symsagittifera roscoffensis

    PubMed Central

    Sprecher, Simon G.; Bernardo-Garcia, F. Javier; van Giesen, Lena; Hartenstein, Volker; Reichert, Heinrich; Neves, Ricardo; Bailly, Xavier; Martinez, Pedro; Brauchle, Michael

    2015-01-01

    ABSTRACT The ability of some animals to regrow their head and brain after decapitation provides a striking example of the regenerative capacity within the animal kingdom. The acoel worm Symsagittifera roscoffensis can regrow its head, brain and sensory head organs within only a few weeks after decapitation. How rapidly and to what degree it also reacquires its functionality to control behavior however remains unknown. We provide here a neuroanatomical map of the brain neuropils of the adult S. roscoffensis and show that after decapitation a normal neuroanatomical organization of the brain is restored in the majority of animals. By testing different behaviors we further show that functionality of both sensory perception and the underlying brain architecture are restored within weeks after decapitation. Interestingly not all behaviors are restored at the same speed and to the same extent. While we find that phototaxis recovered rapidly, geotaxis is not restored within 7 weeks. Our findings show that regeneration of the head, sensory organs and brain result in the restoration of directed navigation behavior, suggesting a tight coordination in the regeneration of certain sensory organs with that of their underlying neural circuits. Thus, at least in S. roscoffensis, the regenerative capacity of different sensory modalities follows distinct paths. PMID:26581588

  10. Development of real-time PCR assay for genetic identification of the mottled skate, Beringraja pulchra.

    PubMed

    Hwang, In Kwan; Lee, Hae Young; Kim, Min-Hee; Jo, Hyun-Su; Choi, Dong-Ho; Kang, Pil-Won; Lee, Yang-Han; Cho, Nam-Soo; Park, Ki-Won; Chae, Ho Zoon

    2015-10-01

    The mottled skate, Beringraja pulchra is one of the commercially important fishes in the market today. However, B. pulchra identification methods have not been well developed. The current study reports a novel real-time PCR method based on TaqMan technology developed for the genetic identification of B. pulchra. The mitochondrial cytochrome oxidase subunit 1 (COI) nucleotide sequences of 29 B. pulchra, 157 skates and rays reported in GenBank DNA database were comparatively analyzed and the COI sequences specific to B. pulchra was identified. Based on this information, a system of specific primers and Minor Groove Binding (MGB) TaqMan probe were designed. The assay successfully discriminated in 29 specimens of B. pulchra and 27 commercial samples with unknown species identity. For B. pulchra DNA, an average Threshold Cycle (Ct) value of 19.1±0.1 was obtained. Among 27 commercial samples, two samples showed average Ct values 19.1±0.0 and 26.7±0.1, respectively and were confirmed to be B. pulchra based on sequencing. The other samples tested showed undetectable or extremely weak signals for the target fragment, which was also consistent with the sequencing results. These results reveal that the method developed is a rapid and efficient tool to identify B. pulchra and might prevent fraud or mislabeling during the distribution of B. pulchra products.

  11. Phylogenetic distribution of microRNAs supports the basal position of acoel flatworms and the polyphyly of Platyhelminthes.

    PubMed

    Sempere, Lorenzo F; Martinez, Pedro; Cole, Charles; Baguñà, Jaume; Peterson, Kevin J

    2007-01-01

    Phylogenetic analyses based on gene sequences suggest that acoel flatworms are not members of the phylum Platyhelminthes, but instead are the most basal branch of triploblastic bilaterians. Nonetheless, this result has been called into question. An alternative test is to use qualitative molecular markers that should, in principle, exclude the possibility of convergent (homoplastic) evolution in unrelated groups. microRNAs (miRNAs), noncoding regulatory RNA molecules that are under intense stabilizing selection, are a newly discovered set of phylogenetic markers that can resolve such taxonomic disputes. The acoel Childia sp. has recently been shown to possess a subset of the conserved core of miRNAs found across deuterostomes and protostomes, whereas a polyclad flatworm-in addition to this core subset-possesses miRNAs restricted to just protostomes. Here, we examine another acoel, Symsagittifera roscoffensis, and three other platyhelminths. Our results show that the distribution of miRNAs in S. roscoffensis parallels that of Childia. In addition, two of 13 new miRNAs cloned from a triclad flatworm are also found in other lophotrochozoan protostomes, but not in ecdysozoans, deuterostomes, or in basal metazoans including acoels. The limited set of miRNAs found in acoels, intermediate between the even more reduced set in cnidarians and the larger and expanding set in the rest of bilaterians, is compelling evidence for the basal position of acoel flatworms and the polyphyly of Platyhelminthes.

  12. Whole-body acoel regeneration is controlled by Wnt and Bmp-Admp signaling.

    PubMed

    Srivastava, Mansi; Mazza-Curll, Kathleen L; van Wolfswinkel, Josien C; Reddien, Peter W

    2014-05-19

    Whole-body regeneration is widespread in the Metazoa, yet little is known about how underlying molecular mechanisms compare across phyla. Acoels are an enigmatic phylum of invertebrate worms that can be highly informative about many questions in bilaterian evolution, including regeneration. We developed the three-banded panther worm, Hofstenia miamia, as a new acoelomorph model system for molecular studies of regeneration. Hofstenia were readily cultured, with accessible embryos, juveniles, and adults for experimentation. We developed molecular resources and tools for Hofstenia, including a transcriptome and robust systemic RNAi. We report the identification of molecular mechanisms that promote whole-body regeneration in Hofstenia. Wnt signaling controls regeneration of the anterior-posterior axis, and Bmp-Admp signaling controls regeneration of the dorsal-ventral axis. Perturbation of these pathways resulted in regeneration-abnormal phenotypes involving axial feature duplication, such as the regeneration of two heads following Wnt perturbation or the regeneration of ventral cells in place of dorsal ones following bmp or admp RNAi. Hofstenia regenerative mechanisms are strikingly similar to those guiding regeneration in planarians. However, phylogenetic analyses using the Hofstenia transcriptome support an early branching position for acoels among bilaterians, with the last common ancestor of acoels and planarians being the ancestor of the Bilateria. Therefore, these findings identify similar whole-body regeneration mechanisms in animals separated by more than 550 million years of evolution.

  13. The chimerical and multifaceted marine acoel Symsagittifera roscoffensis: from photosymbiosis to brain regeneration.

    PubMed

    Bailly, Xavier; Laguerre, Laurent; Correc, Gaëlle; Dupont, Sam; Kurth, Thomas; Pfannkuchen, Anja; Entzeroth, Rolf; Probert, Ian; Vinogradov, Serge; Lechauve, Christophe; Garet-Delmas, Marie-José; Reichert, Heinrich; Hartenstein, Volker

    2014-01-01

    A remarkable example of biological engineering is the capability of some marine animals to take advantage of photosynthesis by hosting symbiotic algae. This capacity, referred to as photosymbiosis, is based on structural and functional complexes that involve two distantly unrelated organisms. These stable photosymbiotic associations between metazoans and photosynthetic protists play fundamental roles in marine ecology as exemplified by reef communities and their vulnerability to global changes threats. Here we introduce a photosymbiotic tidal acoel flatworm, Symsagittifera roscoffensis, and its obligatory green algal photosymbiont, Tetraselmis convolutae (Lack of the algal partner invariably results in acoel lethality emphasizing the mandatory nature of the photosymbiotic algae for the animal's survival). Together they form a composite photosymbiotic unit, which can be reared in controlled conditions that provide easy access to key life-cycle events ranging from early embryogenesis through the induction of photosymbiosis in aposymbiotic juveniles to the emergence of a functional "solar-powered" mature stage. Since it is possible to grow both algae and host under precisely controlled culture conditions, it is now possible to design a range of new experimental protocols that address the mechanisms and evolution of photosymbiosis. S. roscoffensis thus represents an emerging model system with experimental advantages that complement those of other photosymbiotic species, in particular corals. The basal taxonomic position of S. roscoffensis (and acoels in general) also makes it a relevant model for evolutionary studies of development, stem cell biology and regeneration. Finally, it's autotrophic lifestyle and lack of calcification make S. roscoffensis a favorable system to study the role of symbiosis in the response of marine organisms to climate change (e.g., ocean warming and acidification). In this article we summarize the state of knowledge of the biology of S

  14. The chimerical and multifaceted marine acoel Symsagittifera roscoffensis: from photosymbiosis to brain regeneration.

    PubMed

    Bailly, Xavier; Laguerre, Laurent; Correc, Gaëlle; Dupont, Sam; Kurth, Thomas; Pfannkuchen, Anja; Entzeroth, Rolf; Probert, Ian; Vinogradov, Serge; Lechauve, Christophe; Garet-Delmas, Marie-José; Reichert, Heinrich; Hartenstein, Volker

    2014-01-01

    A remarkable example of biological engineering is the capability of some marine animals to take advantage of photosynthesis by hosting symbiotic algae. This capacity, referred to as photosymbiosis, is based on structural and functional complexes that involve two distantly unrelated organisms. These stable photosymbiotic associations between metazoans and photosynthetic protists play fundamental roles in marine ecology as exemplified by reef communities and their vulnerability to global changes threats. Here we introduce a photosymbiotic tidal acoel flatworm, Symsagittifera roscoffensis, and its obligatory green algal photosymbiont, Tetraselmis convolutae (Lack of the algal partner invariably results in acoel lethality emphasizing the mandatory nature of the photosymbiotic algae for the animal's survival). Together they form a composite photosymbiotic unit, which can be reared in controlled conditions that provide easy access to key life-cycle events ranging from early embryogenesis through the induction of photosymbiosis in aposymbiotic juveniles to the emergence of a functional "solar-powered" mature stage. Since it is possible to grow both algae and host under precisely controlled culture conditions, it is now possible to design a range of new experimental protocols that address the mechanisms and evolution of photosymbiosis. S. roscoffensis thus represents an emerging model system with experimental advantages that complement those of other photosymbiotic species, in particular corals. The basal taxonomic position of S. roscoffensis (and acoels in general) also makes it a relevant model for evolutionary studies of development, stem cell biology and regeneration. Finally, it's autotrophic lifestyle and lack of calcification make S. roscoffensis a favorable system to study the role of symbiosis in the response of marine organisms to climate change (e.g., ocean warming and acidification). In this article we summarize the state of knowledge of the biology of S

  15. Coordinated spatial and temporal expression of Hox genes during embryogenesis in the acoel Convolutriloba longifissura

    PubMed Central

    Hejnol, Andreas; Martindale, Mark Q

    2009-01-01

    Background Hox genes are critical for patterning the bilaterian anterior-posterior axis. The evolution of their clustered genomic arrangement and ancestral function has been debated since their discovery. As acoels appear to represent the sister group to the remaining Bilateria (Nephrozoa), investigating Hox gene expression will provide an insight into the ancestral features of the Hox genes in metazoan evolution. Results We describe the expression of anterior, central and posterior class Hox genes and the ParaHox ortholog Cdx in the acoel Convolutriloba longifissura. Expression of all three Hox genes begins contemporaneously after gastrulation and then resolves into staggered domains along the anterior-posterior axis, suggesting that the spatial coordination of Hox gene expression was present in the bilaterian ancestor. After early surface ectodermal expression, the anterior and central class genes are expressed in small domains of putative neural precursor cells co-expressing ClSoxB1, suggesting an evolutionary early function of Hox genes in patterning parts of the nervous system. In contrast, the expression of the posterior Hox gene is found in all three germ layers in a much broader posterior region of the embryo. Conclusion Our results suggest that the ancestral set of Hox genes was involved in the anterior-posterior patterning of the nervous system of the last common bilaterian ancestor and were later co-opted for patterning in diverse tissues in the bilaterian radiation. The lack of temporal colinearity of Hox expression in acoels may be due to a loss of genomic clustering in this clade or, alternatively, temporal colinearity may have arisen in conjunction with the expansion of the Hox cluster in the Nephrozoa. PMID:19796382

  16. The chimerical and multifaceted marine acoel Symsagittifera roscoffensis: from photosymbiosis to brain regeneration

    PubMed Central

    Bailly, Xavier; Laguerre, Laurent; Correc, Gaëlle; Dupont, Sam; Kurth, Thomas; Pfannkuchen, Anja; Entzeroth, Rolf; Probert, Ian; Vinogradov, Serge; Lechauve, Christophe; Garet-Delmas, Marie-José; Reichert, Heinrich; Hartenstein, Volker

    2014-01-01

    A remarkable example of biological engineering is the capability of some marine animals to take advantage of photosynthesis by hosting symbiotic algae. This capacity, referred to as photosymbiosis, is based on structural and functional complexes that involve two distantly unrelated organisms. These stable photosymbiotic associations between metazoans and photosynthetic protists play fundamental roles in marine ecology as exemplified by reef communities and their vulnerability to global changes threats. Here we introduce a photosymbiotic tidal acoel flatworm, Symsagittifera roscoffensis, and its obligatory green algal photosymbiont, Tetraselmis convolutae (Lack of the algal partner invariably results in acoel lethality emphasizing the mandatory nature of the photosymbiotic algae for the animal's survival). Together they form a composite photosymbiotic unit, which can be reared in controlled conditions that provide easy access to key life-cycle events ranging from early embryogenesis through the induction of photosymbiosis in aposymbiotic juveniles to the emergence of a functional “solar-powered” mature stage. Since it is possible to grow both algae and host under precisely controlled culture conditions, it is now possible to design a range of new experimental protocols that address the mechanisms and evolution of photosymbiosis. S. roscoffensis thus represents an emerging model system with experimental advantages that complement those of other photosymbiotic species, in particular corals. The basal taxonomic position of S. roscoffensis (and acoels in general) also makes it a relevant model for evolutionary studies of development, stem cell biology and regeneration. Finally, it's autotrophic lifestyle and lack of calcification make S. roscoffensis a favorable system to study the role of symbiosis in the response of marine organisms to climate change (e.g., ocean warming and acidification). In this article we summarize the state of knowledge of the biology of S

  17. Structure of the central nervous system of a juvenile acoel, Symsagittifera roscoffensis.

    PubMed

    Bery, Amandine; Cardona, Albert; Martinez, Pedro; Hartenstein, Volker

    2010-09-01

    The neuroarchitecture of Acoela has been at the center of morphological debates. Some authors, using immunochemical tools, suggest that the nervous system in Acoela is organized as a commissural brain that bears little resemblance to the central, ganglionic type brain of other flatworms, and bilaterians in general. Others, who used histological staining on paraffin sections, conclude that it is a compact structure (an endonal brain; e.g., Raikova 2004; von Graff 1891; Delage Arch Zool Exp Gén 4:109-144, 1886). To address this question with modern tools, we have obtained images from serial transmission electron microscopic sections of the entire hatchling of Symsagittifera roscoffensis. In addition, we obtained data from wholemounts of hatchlings labeled with markers for serotonin and tyrosinated tubulin. Our data show that the central nervous system of a juvenile S. roscoffensis consists of an anterior compact brain, formed by a dense, bilobed mass of neuronal cell bodies surrounding a central neuropile. The neuropile flanks the median statocyst and contains several types of neurites, classified according to their types of synaptic vesicles. The neuropile issues three pairs of nerve cords that run at different dorso-ventral positions along the whole length of the body. Neuronal cell bodies flank the cords, and neuromuscular synapses are abundant. The TEM analysis also reveals different classes of peripheral sensory neurons and provides valuable information about the spatial relationships between neurites and other cell types within the brain and nerve cords. We conclude that the acoel S. roscoffensis has a central brain that is comparable in size and architecture to the brain of other (rhabditophoran) flatworms.

  18. Structure of the central nervous system of a juvenile acoel, Symsagittifera roscoffensis

    PubMed Central

    Cardona, Albert; Martinez, Pedro

    2010-01-01

    The neuroarchitecture of Acoela has been at the center of morphological debates. Some authors, using immunochemical tools, suggest that the nervous system in Acoela is organized as a commissural brain that bears little resemblance to the central, ganglionic type brain of other flatworms, and bilaterians in general. Others, who used histological staining on paraffin sections, conclude that it is a compact structure (an endonal brain; e.g., Raikova 2004; von Graff 1891; Delage Arch Zool Exp Gén 4:109-144, 1886). To address this question with modern tools, we have obtained images from serial transmission electron microscopic sections of the entire hatchling of Symsagittifera roscoffensis. In addition, we obtained data from wholemounts of hatchlings labeled with markers for serotonin and tyrosinated tubulin. Our data show that the central nervous system of a juvenile S. roscoffensis consists of an anterior compact brain, formed by a dense, bilobed mass of neuronal cell bodies surrounding a central neuropile. The neuropile flanks the median statocyst and contains several types of neurites, classified according to their types of synaptic vesicles. The neuropile issues three pairs of nerve cords that run at different dorso-ventral positions along the whole length of the body. Neuronal cell bodies flank the cords, and neuromuscular synapses are abundant. The TEM analysis also reveals different classes of peripheral sensory neurons and provides valuable information about the spatial relationships between neurites and other cell types within the brain and nerve cords. We conclude that the acoel S. roscoffensis has a central brain that is comparable in size and architecture to the brain of other (rhabditophoran) flatworms. PMID:20549514

  19. Dissociation of Circadian and Circatidal Timekeeping in the Marine Crustacean Eurydice pulchra

    PubMed Central

    Zhang, Lin; Hastings, Michael H.; Green, Edward W.; Tauber, Eran; Sladek, Martin; Webster, Simon G.; Kyriacou, Charalambos P.; Wilcockson, David C.

    2013-01-01

    Summary Background Tidal (12.4 hr) cycles of behavior and physiology adapt intertidal organisms to temporally complex coastal environments, yet their underlying mechanism is unknown. However, the very existence of an independent “circatidal” clock has been disputed, and it has been argued that tidal rhythms arise as a submultiple of a circadian clock, operating in dual oscillators whose outputs are held in antiphase i.e., ∼12.4 hr apart. Results We demonstrate that the intertidal crustacean Eurydice pulchra (Leach) exhibits robust tidal cycles of swimming in parallel to circadian (24 hr) rhythms in behavioral, physiological and molecular phenotypes. Importantly, ∼12.4 hr cycles of swimming are sustained in constant conditions, they can be entrained by suitable stimuli, and they are temperature compensated, thereby meeting the three criteria that define a biological clock. Unexpectedly, tidal rhythms (like circadian rhythms) are sensitive to pharmacological inhibition of Casein kinase 1, suggesting the possibility of shared clock substrates. However, cloning the canonical circadian genes of E. pulchra to provide molecular markers of circadian timing and also reagents to disrupt it by RNAi revealed that environmental and molecular manipulations that confound circadian timing do not affect tidal timing. Thus, competent circadian timing is neither an inevitable nor necessary element of tidal timekeeping. Conclusions We demonstrate that tidal rhythms are driven by a dedicated circatidal pacemaker that is distinct from the circadian system of E. pulchra, thereby resolving a long-standing debate regarding the nature of the circatidal mechanism. PMID:24076244

  20. Protective effect of Millettia pulchra polysaccharide on cognitive impairment induced by D-galactose in mice.

    PubMed

    Lin, Xing; Huang, Zhongshi; Chen, Xiaoyu; Rong, Yanping; Zhang, Shijun; Jiao, Yang; Huang, Quanfang; Huang, Renbin

    2014-01-30

    A polysaccharide (PMP) was isolated from Millettia pulchra and purified by DEAE-cellulose and Sephadex G-75 chromatography. The results showed that PMP was composed of d-glucose and d-arabinose in a molar ratio of 90.79% and 9.21%, with an average molecular weight of about 14,301 Da. Furthermore, the effect of PMP on cognitive impairment induced by d-galactose in mice was evaluated. Treatment with PMP significantly reversed d-galactose-induced learning and memory impairments, as measured by behavioral tests. One of the potential mechanisms of this action was to reduce oxidative stress and suppress inflammatory responses. Furthermore, our results also showed that PMP markedly reduced the content and deposition of β-amyloid peptide, improved the dysfunction of synaptic plasticity, increased the levels of acetylcholine, but decreased cholinesterase activity. These results suggest that PMP exerts an effective protection against d-galactose-induced cognitive impairment, and PMP may be a major bioactive ingredient in M. pulchra.

  1. Expanding our Understanding of the Seaweed Holobiont: RNA Viruses of the Red Alga Delisea pulchra

    PubMed Central

    Lachnit, Tim; Thomas, Torsten; Steinberg, Peter

    2016-01-01

    Marine seaweeds are holobionts comprised of the macroalgal hosts and their associated microbiota. While the composition of the bacterial component of seaweed microbiomes is increasingly studied, almost nothing is known about the presence, diversity and composition of viruses in macroalgae in situ. In this study, we characterize for the first time the viruses associated with a red macroalga, Delisea pulchra. Using transmission electron microscopy we identified diverse morphotypes of virus-like particles in D. pulchra ranging from icosahedral to bacilliform to coiled pleomorphic as well as bacteriophages. Virome sequencing revealed the presence of a diverse group of dsRNA viruses affiliated to the genus Totivirus, known to infect plant pathogenic fungi. We further identified a ssRNA virus belonging to the order Picornavirales with a close phylogenetic relationship to a pathogenic virus infecting marine diatoms. The results of this study shed light on a so far neglected part of the seaweed holobiont, and suggest that some of the identified viruses may be possible pathogens for a host that is already known to be significantly impacted by bacterial infections. PMID:26779145

  2. Antiinflammatory and Analgesic Activities of Ethanol Extract and Isolated Compounds from Millettia pulchra.

    PubMed

    Huo, Xiaowei; Zhang, Leilei; Gao, Li; Guo, Yan; Zhang, Lijing; Li, Liyong; Si, Jianyong; Cao, Li

    2015-01-01

    The plant Millettia pulchra was commonly used in folk medicine for the management of inflammation. However, there was no scientific rationale for these effects and the mechanism of action remained incompletely understood. The present study was designed to investigate the antiinflammatory and analgesic activities of an ethanol extract of the stem of M. pulchra (EMP) in vivo, and to explore the antiinflammatory activity of compounds isolated from EMP in vitro. We found that EMP reduced xylene-induced ear edema and relieved both acetic acid-induced pain and pain in the hot plate test. Additionally, a significant decrease in nitric oxide (NO) production was observed in cells treated with the isolated compounds. Lanceolatin B, which showed the greatest inhibition of NO synthesis among the compounds tested, also reduced levels of interleukin-1 beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB), and phosphorylation inhibitory kappa B alpha (p-IκBα) in a dose-dependent manner. These findings provide convincing evidence that EMP and the individual isolated compounds possess significant antiinflammatory and analgesic activities. PMID:26062514

  3. Protective effect of Millettia pulchra polysaccharide on cognitive impairment induced by D-galactose in mice.

    PubMed

    Lin, Xing; Huang, Zhongshi; Chen, Xiaoyu; Rong, Yanping; Zhang, Shijun; Jiao, Yang; Huang, Quanfang; Huang, Renbin

    2014-01-30

    A polysaccharide (PMP) was isolated from Millettia pulchra and purified by DEAE-cellulose and Sephadex G-75 chromatography. The results showed that PMP was composed of d-glucose and d-arabinose in a molar ratio of 90.79% and 9.21%, with an average molecular weight of about 14,301 Da. Furthermore, the effect of PMP on cognitive impairment induced by d-galactose in mice was evaluated. Treatment with PMP significantly reversed d-galactose-induced learning and memory impairments, as measured by behavioral tests. One of the potential mechanisms of this action was to reduce oxidative stress and suppress inflammatory responses. Furthermore, our results also showed that PMP markedly reduced the content and deposition of β-amyloid peptide, improved the dysfunction of synaptic plasticity, increased the levels of acetylcholine, but decreased cholinesterase activity. These results suggest that PMP exerts an effective protection against d-galactose-induced cognitive impairment, and PMP may be a major bioactive ingredient in M. pulchra. PMID:24299809

  4. Characteristics of hemolytic activity induced by skin secretions of the frog Kaloula pulchra hainana

    PubMed Central

    2013-01-01

    Background The hemolytic activity of skin secretions obtained by stimulating the frog Kaloula pulchra hainana with diethyl ether was tested using human, cattle, rabbit, and chicken erythrocytes. The skin secretions had a significant concentration-dependent hemolytic effect on erythrocytes. The hemolytic activity of the skin secretions was studied in the presence of osmotic protectants (polyethylene glycols and carbohydrates), cations (Mg2+, Ca2+, Ba2+, Cu2+, and K+), or antioxidants (ascorbic acid, reduced glutathione, and cysteine). Results Depending on their molecular mass, osmotic protectants effectively inhibited hemolysis. The inhibition of skin hemolysis was observed after treatment with polyethylene glycols (1000, 3400, and 6000 Da). Among divalent cations, only 1 mM Cu2+ markedly inhibited hemolytic activity. Antioxidant compounds slightly reduced the hemolytic activity. Conclusions The results suggested that skin secretions of K. pulchra hainana induce a pore-forming mechanism to form pores with a diameter of 1.36-2.0 nm rather than causing oxidative damage to the erythrocyte membrane. PMID:24499077

  5. A new species of Centris ( Centris) (Fabricius) from northeastern Brazil, with taxonomic notes on C. ( C.) pulchra Moure, Oliveira & Viana (Hymenoptera, Apidae)

    PubMed Central

    Mahlmann, Thiago; de Oliveira, Favízia Freitas

    2012-01-01

    Abstract We describe a new species of the bee genus Centris, Centris (Centris) byrsonimae Mahlmann & Oliveira sp. n., whose name has appeared as a nomen nudum in the literature since 1985. Further, a new species group of Centris s.str. is proposed, the pulchra group, based on morphological characters, which comprises the species Centris pulchra Moure, Oliveira & Viana, 2003 and Centris byrsonimae sp. n..Based on information from specimen labels studied and data from the literature, a list of plant species visited by the pulchra group is presented. The male genitalia and hidden metasomal sterna 7 and 8 of Centris pulchra are described for the first time. Typographic errors pertaining to the paratype labels reported in the original description of Centris pulchra are corrected. One female paratype of Centris pulchra is designated herein as a paratype of Centris byrsonimae sp. n. An updated list of species of Centris s.str. from northeastern Brazil is provided including references about geographic distributions as well as an identification key to the pulchra species group. PMID:23459508

  6. Community structure and functional gene profile of bacteria on healthy and diseased thalli of the red seaweed Delisea pulchra.

    PubMed

    Fernandes, Neil; Steinberg, Peter; Rusch, Doug; Kjelleberg, Staffan; Thomas, Torsten

    2012-01-01

    Disease is increasingly viewed as a major factor in the ecology of marine communities and its impact appears to be increasing with environmental change, such as global warming. The temperate macroalga Delisea pulchra bleaches in Southeast Australia during warm summer periods, a phenomenon which previous studies have indicated is caused by a temperature induced bacterial disease. In order to better understand the ecology of this disease, the bacterial communities associated with threes type of samples was investigated using 16S rRNA gene and environmental shotgun sequencing: 1) unbleached (healthy) D. pulchra 2) bleached parts of D. pulchra and 3) apparently healthy tissue adjacent to bleached regions. Phylogenetic differences between healthy and bleached communities mainly reflected relative changes in the taxa Colwelliaceae, Rhodobacteraceae, Thalassomonas and Parvularcula. Comparative metagenomics showed clear difference in the communities of healthy and diseased D. pulchra as reflected by changes in functions associated with transcriptional regulation, cation/multidrug efflux and non-ribosomal peptide synthesis. Importantly, the phylogenetic and functional composition of apparently healthy tissue adjacent to bleached sections of the thalli indicated that changes in the microbial communities already occur in the absence of visible tissue damage. This shift in unbleached sections might be due to the decrease in furanones, algal metabolites which are antagonists of bacterial quorum sensing. This study reveals the complex shift in the community composition associated with bleaching of Delisea pulchra and together with previous studies is consistent with a model in which elevated temperatures reduce levels of chemical defenses in stressed thalli, leading to colonization or proliferation by opportunistic pathogens or scavengers.

  7. Induction of metamorphosis in the sea urchin Holopneustes purpurascens by a metabolite complex from the algal host Delisea pulchra.

    PubMed

    Williamson, J E; De Nys, R; Kumar, N; Carson, D G; Steinberg, P D

    2000-06-01

    Most benthic invertebrates have complex life cycles with planktonic larvae that return to the substratum to settle and metamorphose into a benthic stage. Although naturally produced chemical cues have long been thought to be important for the settlement or metamorphosis of invertebrate larvae, few ecologically relevant chemical cues have been clearly identified. The marine echinoid Holopneustes purpurascens has a complex life cycle, with a planktonic, nonfeeding dispersive larva that metamorphoses into a benthic stage that lives in the canopy of subtidal benthic algae such as the red alga Delisea pulchra and the kelp Ecklonia radiata. Recently recruited juveniles are found primarily on D. pulchra, and we hypothesized that this was in response to a chemical cue produced by this alga. Competent larvae metamorphosed in the presence of D. pulchra, or seawater surrounding this alga, but not in response to the presence of E. radiata or its extracts. A cue for metamorphosis was isolated and characterized from D. pulchra and found to be a water-soluble complex of the sugar floridoside and isethionic acid in a 1:1 molar ratio. The floridoside-isethionic acid complex also triggered settlement in H. purpurascens; however, this response was less specific than metamorphosis and was reversible. Larvae of H. purpurascens also metamorphosed in the presence of several other species of red, but not brown or green, algae from their habitat. Floridoside is found only in red algae, suggesting that the floridoside-isethionic acid complex may be acting as a cue for metamorphosis in other red algae as well as in D. pulchra. PMID:10897447

  8. Radical modification of the A-P axis and the evolution of asexual reproduction in Convolutriloba acoels.

    PubMed

    Sikes, James M; Bely, Alexandra E

    2008-01-01

    Acoel worms in the genus Convolutriloba are remarkable in that closely related, morphologically very similar species reproduce asexually by dramatically different processes. Transverse fission, longitudinal fission, and reversed-polarity budding all occur within this genus, indicating an unparalleled ability to alter the A-P axis. Convolutriloba thus offers an exceptional opportunity to investigate the development and evolution of asexual reproduction. Molecular phylogenetic analysis indicates that reversed-polarity budding is ancestral and fission is derived for the genus. A clear difference between budding and fission is indicated by the development of the nervous system, which forms de novo during budding, but regenerates largely by extensions of remaining components of the nervous system during both types of fission. Despite this and other differences between fission and budding, localized muscle disorganization coupled with behaviorally mediated tearing are characteristic of both transverse fission and reversed-polarity budding (though not longitudinal fission), suggesting that a homologous tissue-separation mechanism underlies these two outwardly quite different asexual reproductive modes. We suggest that the ability to split the posterior axis field into two adjacent fields, manifested during both reversed-polarity budding and longitudinal fission, may have been a driving force behind the diversification of asexual reproductive mode in this group.

  9. Effects of Temperature Stress and Aquarium Conditions on the Red Macroalga Delisea pulchra and its Associated Microbial Community.

    PubMed

    Zozaya-Valdés, Enrique; Roth-Schulze, Alexandra J; Thomas, Torsten

    2016-01-01

    In recent years, there has been an increase in the rate and severity of diseases affecting habitat-forming marine organisms, such as corals, sponges, and macroalgae. Delisea pulchra is a temperate red macroalga that suffers from a bleaching disease that is more frequent during summer, when seawater temperatures are elevated and the alga's chemical defense is weakened. A bacterial cause for the disease is implied by previous studies showing that some isolated strains can cause bleaching in vitro and that host-associated microbial communities are distinct between diseased and healthy individuals. However, nothing is known about the successional events in the microbial community that occur during the development of the disease. To study this aspect in the future, we aimed here to develop an experimental setup to study the bleaching disease in a controllable aquarium environment. Application of a temperature stress (up to 27°C) did not cause a clear and consistent pattern of bleaching, suggesting that temperature alone might not be the only or main factor to cause the disease. The results also showed that the aquarium conditions alone are sufficient to produce bleaching symptoms. Microbial community analysis based on 16S rRNA gene fingerprinting and sequencing showed significant changes after 15 days in the aquarium, indicating that the native microbial associates of D. pulchra are not stably maintained. Microbial taxa that were enriched in the aquarium-held D. pulchra thalli, however, did not match on a taxonomic level those that have been found to be enriched in natural bleaching events. Together our observations indicate that environmental factors, other than the ones investigated here, might drive the bleaching disease in D. pulchra and that the aquarium conditions have substantial impact on the alga-associated microbiome.

  10. Effects of Temperature Stress and Aquarium Conditions on the Red Macroalga Delisea pulchra and its Associated Microbial Community

    PubMed Central

    Zozaya-Valdés, Enrique; Roth-Schulze, Alexandra J.; Thomas, Torsten

    2016-01-01

    In recent years, there has been an increase in the rate and severity of diseases affecting habitat-forming marine organisms, such as corals, sponges, and macroalgae. Delisea pulchra is a temperate red macroalga that suffers from a bleaching disease that is more frequent during summer, when seawater temperatures are elevated and the alga’s chemical defense is weakened. A bacterial cause for the disease is implied by previous studies showing that some isolated strains can cause bleaching in vitro and that host-associated microbial communities are distinct between diseased and healthy individuals. However, nothing is known about the successional events in the microbial community that occur during the development of the disease. To study this aspect in the future, we aimed here to develop an experimental setup to study the bleaching disease in a controllable aquarium environment. Application of a temperature stress (up to 27°C) did not cause a clear and consistent pattern of bleaching, suggesting that temperature alone might not be the only or main factor to cause the disease. The results also showed that the aquarium conditions alone are sufficient to produce bleaching symptoms. Microbial community analysis based on 16S rRNA gene fingerprinting and sequencing showed significant changes after 15 days in the aquarium, indicating that the native microbial associates of D. pulchra are not stably maintained. Microbial taxa that were enriched in the aquarium-held D. pulchra thalli, however, did not match on a taxonomic level those that have been found to be enriched in natural bleaching events. Together our observations indicate that environmental factors, other than the ones investigated here, might drive the bleaching disease in D. pulchra and that the aquarium conditions have substantial impact on the alga-associated microbiome. PMID:26925036

  11. Trees as huge flowers and flowers as oversized floral guides: the role of floral color change and retention of old flowers in Tibouchina pulchra.

    PubMed

    Brito, Vinícius L G; Weynans, Kevin; Sazima, Marlies; Lunau, Klaus

    2015-01-01

    Floral color changes and retention of old flowers are frequently combined phenomena restricted to the floral guide or single flowers in few-flowered inflorescences. They are thought to increase the attractiveness over long distances and to direct nearby pollinators toward the rewarding flowers. In Tibouchina pulchra, a massively flowering tree, the whole flower changes its color during anthesis. On the first day, the flowers are white and on the next 3 days, they change to pink. This creates a new large-scale color pattern in which the white pre-changed flowers contrast against the pink post-changed ones over the entire tree. We describe the spectral characteristics of floral colors of T. pulchra and test bumblebees' response to this color pattern when viewed at different angles (simulating long and short distances). The results indicated the role of different color components in bumblebee attraction and the possible scenario in which this flower color pattern has evolved. We tested bumblebees' preference for simulated trees with 75% pink and 25% white flowers resembling the color patterns of T. pulchra, and trees with green leaves and pink flowers (control) in long-distance approach. We also compared an artificial setting with three pink flowers and one white flower (T. pulchra model) against four pink flowers with white floral guides (control) in short-distance approach. Bumblebees spontaneously preferred the simulated T. pulchra patterns in both approaches despite similar reward. Moreover, in short distances, pollinator visits to peripheral, non-rewarding flowers occurred only half as frequently in the simulated T. pulchra when compared to the control. Thefore, this exceptional floral color change and the retention of old flowers in T. pulchra favors the attraction of pollinators over long distances in a deception process while it honestly directs them toward the rewarding flowers at short distances possibly exploring their innate color preferences.

  12. Trees as huge flowers and flowers as oversized floral guides: the role of floral color change and retention of old flowers in Tibouchina pulchra

    PubMed Central

    Brito, Vinícius L. G.; Weynans, Kevin; Sazima, Marlies; Lunau, Klaus

    2015-01-01

    Floral color changes and retention of old flowers are frequently combined phenomena restricted to the floral guide or single flowers in few-flowered inflorescences. They are thought to increase the attractiveness over long distances and to direct nearby pollinators toward the rewarding flowers. In Tibouchina pulchra, a massively flowering tree, the whole flower changes its color during anthesis. On the first day, the flowers are white and on the next 3 days, they change to pink. This creates a new large-scale color pattern in which the white pre-changed flowers contrast against the pink post-changed ones over the entire tree. We describe the spectral characteristics of floral colors of T. pulchra and test bumblebees’ response to this color pattern when viewed at different angles (simulating long and short distances). The results indicated the role of different color components in bumblebee attraction and the possible scenario in which this flower color pattern has evolved. We tested bumblebees’ preference for simulated trees with 75% pink and 25% white flowers resembling the color patterns of T. pulchra, and trees with green leaves and pink flowers (control) in long-distance approach. We also compared an artificial setting with three pink flowers and one white flower (T. pulchra model) against four pink flowers with white floral guides (control) in short-distance approach. Bumblebees spontaneously preferred the simulated T. pulchra patterns in both approaches despite similar reward. Moreover, in short distances, pollinator visits to peripheral, non-rewarding flowers occurred only half as frequently in the simulated T. pulchra when compared to the control. Thefore, this exceptional floral color change and the retention of old flowers in T. pulchra favors the attraction of pollinators over long distances in a deception process while it honestly directs them toward the rewarding flowers at short distances possibly exploring their innate color preferences. PMID

  13. Chemical mediation of ternary interactions between marine holobionts and their environment as exemplified by the red alga Delisea pulchra.

    PubMed

    Harder, Tilmann; Campbell, Alexandra H; Egan, Suhelen; Steinberg, Peter D

    2012-05-01

    The need for animals and plants to control microbial colonization is important in the marine environment with its high densities of microscopic propagules and seawater that provides an ideal medium for their dispersal. In contrast to the traditional emphasis on antagonistic interactions of marine organisms with microbes, emerging studies lend support to the notion that health and performance of many marine organisms are functionally regulated and assisted by associated microbes, an ecological concept defined as a holobiont. While antimicrobial activities of marine secondary metabolites have been studied in great depth ex-situ, we are beginning to understand how some of these compounds function in an ecological context to maintain the performance of marine holobionts. The present article reviews two decades of our research on the red seaweed Delisea pulchra by addressing: the defense chemistry of this seaweed; chemically-mediated interactions between the seaweed and its natural enemies; and the negative influence of elevated seawater temperature on these interactions. Our understanding of these defense compounds and the functional roles they play for D. pulchra extends from molecular interactions with bacterial cell signaling molecules, to ecosystem-scale consequences of chemically-controlled disease and herbivory. Delisea pulchra produces halogenated furanones that antagonize the same receptor as acylated homoserine lactones (AHL)-a group of widespread intercellular communication signals among bacteria. Halogenated furanones compete with and inhibit bacterial cell-to-cell communication, and thus interfere with important bacterial communication-regulated processes, such as biofilm formation. In a predictable pattern that occurs at the ecological level of entire populations, environmental stress interferes with the production of halogenated furanones, causing downstream processes that ultimately result in disease of the algal holobiont. PMID:22527059

  14. Genomes and Virulence Factors of Novel Bacterial Pathogens Causing Bleaching Disease in the Marine Red Alga Delisea pulchra

    PubMed Central

    Fernandes, Neil; Case, Rebecca J.; Longford, Sharon R.; Seyedsayamdost, Mohammad R.; Steinberg, Peter D.; Kjelleberg, Staffan; Thomas, Torsten

    2011-01-01

    Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolysins, and global regulatory mechanisms that may allow for the switch of Nautella sp. R11 to a pathogenic lifestyle. Many virulence effectors common in phytopathogenic bacteria are also found in the R11 genome, such as the plant hormone indole acetic acid, cellulose fibrils, succinoglycan and nodulation protein L. Comparative genomics with non-pathogenic Roseobacter strains and a newly identified pathogen, Phaeobacter sp. LSS9, revealed a patchy distribution of putative virulence factors in all genomes, but also led to the identification of a quorum sensing (QS) dependent transcriptional regulator that was unique to pathogenic Roseobacter strains. This observation supports the model that a combination of virulence factors and QS-dependent regulatory mechanisms enables indigenous members of the host alga's epiphytic microbial community to switch to a pathogenic lifestyle, especially under environmental conditions when innate host defence mechanisms are compromised. PMID:22162749

  15. Rapid Development of Microsatellite Markers with 454 Pyrosequencing in a Vulnerable Fish, the Mottled Skate, Raja pulchra

    PubMed Central

    Kang, Jung-Ha; Park, Jung-Youn; Jo, Hyun-Su

    2012-01-01

    The mottled skate, Raja pulchra, is an economically valuable fish. However, due to a severe population decline, it is listed as a vulnerable species by the International Union for Conservation of Nature. To analyze its genetic structure and diversity, microsatellite markers were developed using 454 pyrosequencing. A total of 17,033 reads containing dinucleotide microsatellite repeat units (mean, 487 base pairs) were identified from 453,549 reads. Among 32 loci containing more than nine repeat units, 20 primer sets (62%) produced strong PCR products, of which 14 were polymorphic. In an analysis of 60 individuals from two R. pulchra populations, the number of alleles per locus ranged from 1–10, and the mean allelic richness was 4.7. No linkage disequilibrium was found between any pair of loci, indicating that the markers were independent. The Hardy–Weinberg equilibrium test showed significant deviation in two of the 28 single-loci after sequential Bonferroni’s correction. Using 11 primer sets, cross-species amplification was demonstrated in nine related species from four families within two classes. Among the 11 loci amplified from three other Rajidae family species; three loci were polymorphic. A monomorphic locus was amplified in all three Rajidae family species and the Dasyatidae family. Two Rajidae polymorphic loci amplified monomorphic target DNAs in four species belonging to the Carcharhiniformes class, and another was polymorphic in two Carcharhiniformes species. PMID:22837688

  16. Characterization of flavonoids in the ethomedicine Fordiae Cauliflorae Radix and its adulterant Millettiae Pulchrae Radix by HPLC-DAD-ESI-IT-TOF-MSn.

    PubMed

    Fan, Lan-Lan; Yi, Tao; Xu, Feng; Zhang, Ya-Zhou; Zhang, Jian-Ye; Li, Dian-Peng; Xie, Yang-Jiao; Qin, Shan-Ding; Chen, Hu-Biao

    2013-01-01

    Fordiae Cauliflorae Radix (FC, the root of Fordia cauliflora Hemsl) and Millettiae Pulchrae Radix [MP, the root of Millettia pulchra (Benth.) Kurz var. laxior (Dunn) Z. Wei], which go under the same local name of "Daluosan", have long been used in Southern China for the treatment of stroke, paralysis, dementia in children, Alzheimer's disease and other diseases. The same local name and similar functions always confuse users. To further utilize these two ethnodrugs and identify them unambiguously, an HPLC-DAD-ESI-IT-TOF-MSn method was developed to separate and characterize the flavonoids in FC and MP. A total of 41 flavonoids were detected, of which six compounds were identified by comparing their retention time and MS data with those of the reference standards, and the others were tentatively identified based on their tandem mass spectrometry data obtained in the positive ion detection mode. Nineteen of these characterized compounds are reported from these two plants for the first time. PMID:24352055

  17. Guanidine Alkaloids from the Marine Sponge Monanchora pulchra Show Cytotoxic Properties and Prevent EGF-Induced Neoplastic Transformation in Vitro

    PubMed Central

    Dyshlovoy, Sergey A.; Tabakmakher, Kseniya M.; Hauschild, Jessica; Shchekaleva, Regina K.; Otte, Katharina; Guzii, Alla G.; Makarieva, Tatyana N.; Kudryashova, Ekaterina K.; Fedorov, Sergey N.; Shubina, Larisa K.; Bokemeyer, Carsten; Honecker, Friedemann; Stonik, Valentin A.; von Amsberg, Gunhild

    2016-01-01

    Guanidine alkaloids from sponges Monanchora spp. represent diverse bioactive compounds, however, the mechanisms underlying bioactivity are very poorly understood. Here, we report results of studies on cytotoxic action, the ability to inhibit EGF-induced neoplastic transformation, and the effects on MAPK/AP-1 signaling of eight rare guanidine alkaloids, recently isolated from the marine sponge Monanchora pulchra, namely: monanchocidin A (1), monanchocidin B (2), monanchomycalin C (3), ptilomycalin A (4), monanchomycalin B (5), normonanchocidin D (6), urupocidin A (7), and pulchranin A (8). All of the compounds induced cell cycle arrest (apart from 8) and programmed death of cancer cells. Ptilomycalin A-like compounds 1–6 activated JNK1/2 and ERK1/2, following AP-1 activation and caused p53-independent programmed cell death. Compound 7 induced p53-independent cell death without activation of AP-1 or caspase-3/7, and the observed JNK1/2 activation did not contribute to the cytotoxic effect of the compound. Alkaloid 8 induced JNK1/2 (but not ERK1/2) activation leading to p53-independent cell death and strong suppression of AP-1 activity. Alkaloids 1–4, 7, and 8 were able to inhibit the EGF-induced neoplastic transformation of JB6 P+ Cl41 cells. Our results suggest that investigated guanidine marine alkaloids hold potential to eliminate human cancer cells and prevent cancer cell formation and spreading. PMID:27428983

  18. Chemopreventive flavonoids from Millettia pulchra Kurz var-laxior (Dunn) Z.Wei (Yulangsan) function as Michael reaction acceptors.

    PubMed

    Wang, Wenli; Wang, Jian; Li, Ning; Zhang, Xiangrong; Zhao, Weihong; Li, Jiayuan; Si, Yingying

    2015-03-01

    Natural NQO1 [NAD(P)H quinine oxidoreductase 1] inducing agents play a critical role in cancer chemoprevention. The expression of NQO1 is regulated by Michael reaction acceptors (MRAs) via the Keap1/Nrf2/ARE signaling pathway. The aims of this study were to identify and characterize novel effective chemopreventive agents from naturally occurring products. Using bioassay-guided isolation approaches 16 bioactive MRAs from Millettia pulchra Kurz var-laxior (Dunn) Z.Wei, also called Yulangsan as a famous Zhuang medicine. The structures were elucidated as chalcone (1-7), flavonone (8-14), flavanone (15) and isoflavan (16). Their electrophilic abilities and NQO1 inducing activity were assessed using GSH (glutathione) rapid screening, and in vitro cell-based (Hepa 1c1c7 cells) assay, respectively. Compounds 3, 4, 6, 13, and 14 showed to have NQO1 inducing activity. Among them, compounds 4 and 14 interact with NQO1 at Gly 149, Gly 150, Phe 106, Typ 105 and His 161, revealed by molecular docking studies. PMID:25630222

  19. Guanidine Alkaloids from the Marine Sponge Monanchora pulchra Show Cytotoxic Properties and Prevent EGF-Induced Neoplastic Transformation in Vitro.

    PubMed

    Dyshlovoy, Sergey A; Tabakmakher, Kseniya M; Hauschild, Jessica; Shchekaleva, Regina K; Otte, Katharina; Guzii, Alla G; Makarieva, Tatyana N; Kudryashova, Ekaterina K; Fedorov, Sergey N; Shubina, Larisa K; Bokemeyer, Carsten; Honecker, Friedemann; Stonik, Valentin A; von Amsberg, Gunhild

    2016-01-01

    Guanidine alkaloids from sponges Monanchora spp. represent diverse bioactive compounds, however, the mechanisms underlying bioactivity are very poorly understood. Here, we report results of studies on cytotoxic action, the ability to inhibit EGF-induced neoplastic transformation, and the effects on MAPK/AP-1 signaling of eight rare guanidine alkaloids, recently isolated from the marine sponge Monanchora pulchra, namely: monanchocidin A (1), monanchocidin B (2), monanchomycalin C (3), ptilomycalin A (4), monanchomycalin B (5), normonanchocidin D (6), urupocidin A (7), and pulchranin A (8). All of the compounds induced cell cycle arrest (apart from 8) and programmed death of cancer cells. Ptilomycalin A-like compounds 1-6 activated JNK1/2 and ERK1/2, following AP-1 activation and caused p53-independent programmed cell death. Compound 7 induced p53-independent cell death without activation of AP-1 or caspase-3/7, and the observed JNK1/2 activation did not contribute to the cytotoxic effect of the compound. Alkaloid 8 induced JNK1/2 (but not ERK1/2) activation leading to p53-independent cell death and strong suppression of AP-1 activity. Alkaloids 1-4, 7, and 8 were able to inhibit the EGF-induced neoplastic transformation of JB6 P⁺ Cl41 cells. Our results suggest that investigated guanidine marine alkaloids hold potential to eliminate human cancer cells and prevent cancer cell formation and spreading. PMID:27428983

  20. Antibacterial and anti-inflammatory activities of an extract, fractions, and compounds isolated from Gochnatia pulchra aerial parts

    PubMed Central

    Lucarini, R.; Tozatti, M.G.; Silva, M.L.A.; Gimenez, V.M.M.; Pauletti, P.M.; Groppo, M.; Turatti, I.C.C.; Cunha, W.R.; Martins, C.H.G.

    2015-01-01

    This paper reports on the in vitro antibacterial and in vivo anti-inflammatory properties of a hydroethanolic extract of the aerial parts of Gochnatia pulchra (HEGP). It also describes the antibacterial activity of HEGP fractions and of the isolated compounds genkwanin, scutellarin, apigenin, and 3,5-O-dicaffeoylquinic acid, as evaluated by a broth microdilution method. While HEGP and its fractions did not provide promising results, the isolated compounds exhibited pronounced antibacterial activity. The most sensitive microorganism was Streptococcus pyogenes, with minimum inhibitory concentration (MIC) values of 100, 50 and 25 µg/mL for genkwanin and the flavonoids apigenin and scutellarin, respectively. Genkwanin produced an MIC value of 25 µg/mL against Enterococcus faecalis. A paw edema model in rats and a pleurisy inflammation model in mice aided investigation of the anti-inflammatory effects of HEGP. This study also evaluated the ability of HEGP to modulate carrageenan-induced interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) production. Orally administered HEGP (250 and 500 mg/kg) inhibited carrageenan-induced paw edema. Regarding carrageenan-induced pleurisy, HEGP at 50, 100, and 250 mg/kg diminished leukocyte migration by 71.43%, 69.24%, and 73.34% (P<0.05), respectively. HEGP suppressed IL-1β and MCP-1 production by 55% and 50% at 50 mg/kg (P<0.05) and 60% and 25% at 100 mg/kg (P<0.05), respectively. HEGP abated TNF-α production by macrophages by 6.6%, 33.3%, and 53.3% at 100, 250, and 500 mg/kg (P<0.05), respectively. HEGP probably exerts anti-inflammatory effects by inhibiting production of the pro-inflammatory cytokines TNF-α, IL-1β, and MCP-1. PMID:26200228

  1. Establishing the redox potential of Tibouchina pulchra (Cham.) Cogn., a native tree species from the Atlantic Rain Forest, in the vicinity of an oil refinery in SE Brazil.

    PubMed

    Esposito, Marisia Pannia; Domingos, Marisa

    2014-04-01

    The present study aimed to establish the seasonal variations in the redox potential ranges of young Tibouchina pulchra plants growing in the Cubatão region (SE Brazil) under varying levels of oxidative stress caused by air pollutants. The plants were exposed to filtered air (FA) and non-filtered air (NFA) in open-top chambers installed next to an oil refinery in Cubatão during six exposure periods of 90 days each, which included the winter and summer seasons. After exposure, several analyses were performed, including the foliar concentrations of ascorbic acid and glutathione in its reduced (AsA and GSH), total (totAA and totG) and oxidized forms (DHA and GSSG); their ratios (AsA/totAA and GSH/totG); the enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR); and the content of malondialdehyde (MDA). The range of antioxidant responses in T. pulchra plants varied seasonally and was stimulated by high or low air pollutant concentrations and/or air temperatures. Glutathione and APX were primarily responsible for increasing plant tolerance to oxidative stress originating from air pollution in the region. The high or low air temperatures mainly affected enzymatic activity. The content of MDA increased in response to increasing ozone concentration, thus indicating that the pro-oxidant/antioxidant balance may not have been reached. PMID:24407781

  2. Establishing the redox potential of Tibouchina pulchra (Cham.) Cogn., a native tree species from the Atlantic Rain Forest, in the vicinity of an oil refinery in SE Brazil.

    PubMed

    Esposito, Marisia Pannia; Domingos, Marisa

    2014-04-01

    The present study aimed to establish the seasonal variations in the redox potential ranges of young Tibouchina pulchra plants growing in the Cubatão region (SE Brazil) under varying levels of oxidative stress caused by air pollutants. The plants were exposed to filtered air (FA) and non-filtered air (NFA) in open-top chambers installed next to an oil refinery in Cubatão during six exposure periods of 90 days each, which included the winter and summer seasons. After exposure, several analyses were performed, including the foliar concentrations of ascorbic acid and glutathione in its reduced (AsA and GSH), total (totAA and totG) and oxidized forms (DHA and GSSG); their ratios (AsA/totAA and GSH/totG); the enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR); and the content of malondialdehyde (MDA). The range of antioxidant responses in T. pulchra plants varied seasonally and was stimulated by high or low air pollutant concentrations and/or air temperatures. Glutathione and APX were primarily responsible for increasing plant tolerance to oxidative stress originating from air pollution in the region. The high or low air temperatures mainly affected enzymatic activity. The content of MDA increased in response to increasing ozone concentration, thus indicating that the pro-oxidant/antioxidant balance may not have been reached.

  3. Response of stress indicators and growth parameters of Tibouchina pulchra Cogn. exposed to air and soil pollution near the industrial complex of Cubatão, Brazil.

    PubMed

    Klumpp, G; Furlan, C M; Domingos, M; Klumpp, A

    2000-01-31

    The present study was performed in the vicinity of the industrial complex of Cubatão, São Paulo, Brazil, in order to evaluate the response of 'manaca da serra' Tibouchina pulchra Cogn. (Melastomataceae), a common species of secondary Atlantic Rain Forest vegetation, to the impact of complex air pollution. Emphasis was given to changes of biochemical parameters such as ascorbic acid concentration, peroxidase activity, contents of water-soluble thiols, pH of leaf extract and buffering capacity. These plant factors are often used as early indicators of air pollution stress. Field experiments included sampling of leaves from mature trees in areas with different air pollution load (passive monitoring), exposure of saplings cultivated in uniform soil at these areas (active monitoring) and a study on the combined effects of contaminated soil and air pollution. In general, metabolic response of saplings was more accentuated than that of mature trees. Leaf extract pH and buffering capacity showed no or only small alterations in plants exposed to industrial emissions. In contrast, air pollution resulted in a distinct decrease in ascorbic acid contents and an increase in peroxidase activity and thiol concentrations in leaves. Cultivation of saplings in soil types from contaminated regions frequently caused the same modifications or enhanced the effects produced by air pollution. Growth analysis of exposed saplings demonstrated that a change of the relationship between above-ground and below-ground plant parts was the most obvious effect of air pollution and soil contamination. The experiments showed that even T. pulchra, a species considered resistant to air pollution, suffers metabolic disturbances by the present ambient air and soil quality. Although biochemical and physiological alterations were not related to a certain air pollution type, they could be used to estimate the overall pollution load and to map zones with different air quality.

  4. Physiological responses of the tropical tree Tibouchina pulchra Cogn under the influence of combustion of crude oil and natural gas at an oil refinery.

    PubMed

    Silva, Daiane T; Moraes, Regina M

    2013-04-01

    A refinery located on the slopes of a mountain range in the city of Cubatão (SE-Brazil) is the main source of sulfur dioxide (SO(2)) in the region. For this reason, the refinery replaced a system in which energy was produced from crude oil combustion in boilers with a system of energy and vapor co-generation in a thermoelectric power plant fueled by natural gas. The aim of this study was to investigate the responses of Tibouchina pulchra to the fuel switching. Saplings planted in pots were distributed throughout monitoring sites around the polluting source (sites I, II, III and IV) and in a site (V) far from emissions. Changes on the plants responses occur along the three fuel switching phases. During the last phase, increased carbon assimilation (Asat) and decreased stomatal conductance (gs) were observed in plants growing in sites II and III; as a consequence, intrinsic water use efficiency (iWUE) increased. However, the increase in Asat did not promote growth increase suggesting that changes at the refinery did not result in better air quality, but only in a change in the main contaminants.

  5. Evidence that halogenated furanones from Delisea pulchra inhibit acylated homoserine lactone (AHL)-mediated gene expression by displacing the AHL signal from its receptor protein.

    PubMed

    Manefield, M; de Nys, R; Kumar, N; Read, R; Givskov, M; Steinberg, P; Kjelleberg, S

    1999-02-01

    Acylated homoserine lactone (AHL)-mediated gene expression controls phenotypes involved in colonization, often specifically of higher organisms, in both marine and terrestrial environments. The marine red alga Delisea pulchra produces halogenated furanones which resemble AHLs structurally and show inhibitory activity at ecologically realistic concentrations in AHL bioassays. Evidence is presented that halogenated furanones displace tritiated OHHL [N-3-(oxohexanoyl)-L-homoserine lactone] from Escherichia coli cells overproducing LuxR with potencies corresponding to their respective inhibitory activities in an AHL-regulated bioluminescence assay, indicating that this is the mechanism by which furanones inhibit AHL-dependent phenotypes. Alternative mechanisms for this phenomenon are also addressed. General metabolic disruption was assessed with two-dimensional PAGE, revealing limited non-AHL-related effects. A direct chemical interaction between the algal compounds and AHLs, as monitored by 1H NMR spectroscopy, was shown not to occur in vitro. These results support the contention that furanones, at the concentrations produced by the alga, can control bacterial colonization of surfaces by specifically interfering with AHL-mediated gene expression at the level of the LuxR protein.

  6. Parameterization of the response of calcification to temperature and pCO2 in the coral Acropora pulchra and the alga Lithophyllum kotschyanum

    NASA Astrophysics Data System (ADS)

    Comeau, S.; Carpenter, R. C.; Lantz, C. A.; Edmunds, P. J.

    2016-09-01

    The response of tropical corals and calcifying algae to ocean acidification (OA) and warming has received much attention in the past decade. However, most studies have evaluated the response of organisms to two or three temperature treatments, which does not allow the functional relationship between calcification and temperature under ambient and future pCO2 to be determined. This study tested the hypothesis that the relationship between calcification and temperature is affected by OA in the coral Acropora pulchra and the calcified alga Lithophyllum kotschyanum. Pieces of each organism were incubated under five (24-30 °C) or six (24-31.5 °C) temperatures crossed with two pCO2 levels (400 and 1000 μatm), and calcification was assessed in trials conducted in the spring and summer. The response of coral calcification to temperature was a positive asymmetric parabola with a maximum at ~28 °C under both pCO2 levels and in both seasons; the effects of pCO2 on calcification were largest at ~28 °C and lowest in both cool and warm temperatures. In contrast, calcification of the alga at both levels of pCO2 was unaffected by temperature in spring, but declined linearly with temperature in summer. This study demonstrates that the calcification response of coral reef organisms to the crossed effect of warming and OA is complex and cannot be fully assessed without using multiple temperature treatments that are ecologically relevant.

  7. A novel form of pigment-dispersing hormone in the central nervous system of the intertidal marine isopod, Eurydice pulchra (leach).

    PubMed

    Wilcockson, David C; Zhang, Lin; Hastings, Michael H; Kyriacou, Charalambos P; Webster, Simon G

    2011-02-15

    Pigment-dispersing factor (PDF) is well known as a circadian clock output factor, which drives daily activity rhythms in many insects. The role of its homologue, pigment-dispersing hormone (PDH), in the regulation of circadian and/or circatidal rhythmicity in crustaceans is, however, poorly understood. The intertidal isopod crustacean, Eurydice pulchra has well-defined circatidal (12.4-hour) activity rhythms. In this study we show that this runs parallel to a circadian (24-hour) cycle of chromatophore dispersion. As a first step in determining the potential role of PDH in these rhythms, we have identified a novel form of PDH expressed in this species. Because conventional homology cloning was unsuccessful, we employed immuno-identification and Edman microsequencing to determine the primary structure of this peptide. From this, cDNA cloning identified the nucleotide encoding sequence and thus facilitated description of PDH neurons by in situ hybridization and immunohistochemistry. We show them to be morphologically similar to those that co-ordinate circadian activity rhythms in insects. In animals expressing both tidal (activity) and circadian (chromatophore) rhythms, however, there was no evidence for a corresponding periodicity in the expression of pdh transcript, as determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in Eurydice heads. It is therefore suggested that any role for PDH in daily/tidal timing in Eurydice is not mediated at the transcriptional level, rather rhythms in neurohemal release may be important in such co-ordination. PMID:21192084

  8. The effect of 17-methoxyl-7-hydroxy-benzene-furanchalcone isolated from Millettia pulchra on myocardial ischemia in vitro and in vivo.

    PubMed

    Jian, Jie; Qing, Feizhang; Zhang, Shijun; Huang, Jianchun; Huang, Renbin

    2012-08-01

    The effect of 17-methoxyl-7-hydroxy-benzene-furanchalcone isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z. Wei on rat myocardial ischemia has been investigated. An in vitro cardiocyte apoptosis model and an in vivo myocardial ischemia model were used to elucidate the mechanism of 17-methoxyl-7-hydroxy-benzene-furanchalcone. In contrast to hydrogen peroxide (H2O2, 100 µmol/L), 17-methoxyl-7-hydroxy-benzene-furanchalcone in vitro (255 and 510 µmol/L) increased the quantity of total superoxide dismutase and the protein expression of B cell lymphoma/leukemia-2, while it inhibited cardiocyte apoptosis, the release of malondialdehyde and tumor necrosis factor α, and protein expression of nuclear factor κ Bp65 and Bcl-2-associated X protein. Furthermore, pretreatment with MHBFC in vivo (10 and 20 mg/kg) decreased heart rate, systolic pressure, diastolic pressure, average pressure, left ventricular systolic pressure, the largest upstroke velocity of the left ventricular pressure (+ dp/dtmax), total antioxidative capability, myoglobin isoenzyme of creatine kinase, and inducible nitric oxide synthase, while it increased endothelial nitric oxide synthase, ATPases, left ventricular diastolic pressure, left ventricular end-diastolic pressure, the largest descendent velocity of the left ventricular pressure (-dp/dtmax) and the interval from the beginning of left ventricular contraction to +dp/dtmax (t - dp/dtmax), all in a dose-dependent manner. Our present results suggest that 17-methoxyl-7-hydroxy-benzene-furanchalcone is an attractive antimyocardial ischemia agent mostly because of its negative heart rate and negative inotropic effects, the reduction in myocardial oxidative damage, and the modulating expression of genes associated with apoptosis, which improves diastolic function. PMID:22700048

  9. Determination of five flavonoids in different parts of Fordia cauliflora by ultra performance liquid chromatography/triple-quadrupole mass spectrometry and chemical comparison with the root of Millettia pulchra var. laxior

    PubMed Central

    2013-01-01

    Background The root of Fordia cauliflora Hemsl (FC) has long been used in southern China for the treatment of rheumatism, bruises, dementia in children, and valetudinarianism. However, sometimes it is mixed with other parts. And it has always been confused with the root of Millettia pulchra (Benth.) Kurz var. laxior (Dunn) Z. Wei (MP) by the local people. The chemical differences between the two ethnic drugs are not clear until now. The aim of this study is to develop a precise and accurate method to characterize and quantify multiple chemical components of FC, which is helpful for the quality evaluation and identification of FC. Results A method coupling ultra performance liquid chromatography (UPLC) with triple-quadrupole mass spectrometry (QqQ-MS) was first developed for simultaneous determination of five flavonoids in different parts of FC and the root of MP, based on a UPLC-diode array detection (DAD) fingerprint method. All calibration curves showed good linearity (R2>0.99) within test ranges. The overall LOD and LOQ were lower than 2.5 ng/mL and 5.0 ng/mL, respectively. The RSDs for intra- and inter-day of five analytes were less than 2.83% and 3.04%, respectively. Recovery studies for the quantified compounds were found to be within the range 93.6-99.8% with RSD less than 5.73%. The results suggest that the root, traditionally used medicinal part, yields the highest flavanoid content in FC. Pachycarin A, 3′,4′-dimethoxy(2′′,3′′:7,8) furanoflavone, karanjachromene and isoderricin A can be used to differentiate between FC and MP samples. Conclusions The present method is specific, precise and reliable, and is suitable for characterizing and quantifying multiple chemical components of FC. PMID:23870070

  10. Interception of nutrient rich submarine groundwater discharge seepage on European temperate beaches by the acoel flatworm, Symsagittifera roscoffensis.

    PubMed

    Carvalho, Liliana F; Rocha, Carlos; Fleming, Alexandra; Veiga-Pires, Cristina; Aníbal, Jaime

    2013-10-15

    Submarine groundwater discharge (SGD) occurs in intertidal areas, representing a largely unquantified source of solute fluxes to adjacent coastal zones, with nitrogen being constantly the keynote chemical of concern. In Olhos de Água SGD is present as groundwater springs or merely sub-aerial runoff. The occurrence of the flatworm Symsagittifera roscoffensis is described for the first time in Olhos de Água in connection to seepage flows. To assess the impact of this symbiotic flatworm on the nitrogen associated to groundwater discharge flow at the beach, nitrate uptake experiments were conducted in laboratory microcosms. Our results show that S. roscoffensis actively uptakes nitrate at different rates depending on light availability, with rates ≈ 10 times higher than that of its symbiotic microalgae alone. This supports the hypothesis that S. roscoffensis could be an important in situ nitrate interceptor, potentially playing a biological role on the transformation of groundwater-borne nitrate loads at the land-ocean boundary.

  11. Spawning Characteristics and Artificial Hatching of Female Mottled Skate, Beringraja pulchra in the West Coast of Korea

    PubMed Central

    Kang, Hee-Woong; Jo, Yeong-Rok; Kang, Duk-Yong; Jeong, Gyeong-Suk; Jo, Hyun-Su

    2013-01-01

    The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at 8°C, 13°C, 18°C, water temperature (12.8 to 24.2°C), and the best hatching temperature was 18°C. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate. PMID:25949140

  12. Lipid biosynthesis in the marine flatworm Convoluta roscoffensis and its algal symbiont Platymonas convoluta.

    PubMed

    Meyer, H; Provasoli, L; Meyer, F

    1979-06-21

    As a part of an investigations on the lipid metabolism in Platyhelminthes, the acoel Convoluta roscoffensis, which harbors the green alga Platymonas convoluta as a symbiont, was studied. Isotopic tracer experiments established that the acoel lacks the ability to synthesize de novo long-chain saturated and unsaturated fatty acids and depends on its algal symbiont for these compounds. The acoel's fatty acid composition closely resembles that of the alga but differs from those of other animals; the acoel's polyunsaturated fatty acids are of the plant type (omega 3 family) rather than of the animal type (omega 6 family). The acoel also lacks the ability to synthesize sterols de novo. It contains 24-methylenecholesterol synthesized by the algae and, in addition, significant amounts of cholesterol, which is probably a host modification product of the algal sterol. With fatty acids provided by the symbiont, the acoel has the ability to synthesize its own complex lipids. The acoel contains relatively large amounts of triglyceride, phosphatidylcholine, and ethanolamine plasmalogen. These compounds are either not present at all or present only in minute amounts in the symbiotic alga. Since acoels belong to the most primitive forms of the present-day flatworms, the observed metabolic defects in this organism suggest that mechanisms for the biosynthesis of fatty acids and sterols were lost early during the evolution of the Platyhelminthes, and that this phenomenon is widespread within the phylum.

  13. Mitochondrial genome data support the basal position of acoelomorpha and the polyphyly of the platyhelminthes

    SciTech Connect

    Ruiz-Trillo, Inaki; Riutort, Marta; Fourcade, H. Matthew; Baguna, Jaume; Boore, Jeffrey L.

    2004-05-01

    We determined 9.7, 5.2, and 6.8 kb, respectively, of the mitochondrial genomes of the acoel Paratomella rubra, the nemertodermatid Nemertoderma westbladi and the free-living rhabditophoran platyhelminth Microstomum lineare. The identified gene arrangements are unique among metazoans, including each other, sharing no more than one or two single gene boundaries with a few distantly related taxa. Phylogenetic analysis of the amino acid sequences inferred from the sequenced genes confirms that the acoelomorph flatworms (acoels + nemertodermatids) do not belong to the Platyhelminthes, but are, instead, the most basal extant bilaterian group. Therefore, the Platyhelminthes, as traditionally constituted, is a polyphyletic phylum.

  14. Mitochondrial genome data support the basal position of Acoelomorpha and the polyphyly of the Platyhelminthes.

    PubMed

    Ruiz-Trillo, Iñaki; Riutort, Marta; Fourcade, H Matthew; Baguñà, Jaume; Boore, Jeffrey L

    2004-11-01

    We determined 9.7, 5.2, and 6.8 kb, respectively, of the mitochondrial genomes of the acoel Paratomella rubra, the nemertodermatid Nemertoderma westbladi, and the free-living rhabditophoran platyhelminth Microstomum lineare. The identified gene arrangements are unique among metazoans, including each other, sharing no more than one or two single gene boundaries with a few distantly related taxa. Phylogenetic analysis of the amino acid sequences inferred from the sequenced genes confirms that the acoelomorph flatworms (acoels+nemertodermatids) do not belong to the Platyhelminthes, but are, instead, the most basal extant bilaterian group. Therefore, the Platyhelminthes, as traditionally constituted, is a polyphyletic phylum.

  15. Hidden diversity of Acoelomorpha revealed through metabarcoding

    PubMed Central

    Arroyo, Alicia S.; López-Escardó, David; de Vargas, Colomban

    2016-01-01

    Animals with bilateral symmetry comprise the majority of the described species within Metazoa. However, the nature of the first bilaterian animal remains unknown. As most recent molecular phylogenies point to Xenacoelomorpha as the sister group to the rest of Bilateria, understanding their biology, ecology and diversity is key to reconstructing the nature of the last common bilaterian ancestor (Urbilateria). To date, sampling efforts have focused mainly on coastal areas, leaving potential gaps in our understanding of the full diversity of xenacoelomorphs. We therefore analysed 18S rDNA metabarcoding data from three marine projects covering benthic and pelagic habitats worldwide. Our results show that acoels have a greater richness in planktonic environments than previously described. Interestingly, we also identified a putative novel clade of acoels in the deep benthos that branches as sister group to the rest of Acoela, thus representing the earliest-branching acoel clade. Our data highlight deep-sea environments as an ideal habitat to sample acoels with key phylogenetic positions, which might be useful for reconstructing the early evolution of Bilateria. PMID:27677819

  16. Determination of total sulfur in lichens and plants by combustion-infrared analysis. [Medicago sativa L. ; Vitis labruscana Bailey; Festuca sp. ; Fraxinum pennsylvanica Marsh. ; Paremelia chlorochroa Tuck. ; P. sulcata Tayl. ; Juniperus scopulorum Sarg. ; Artemisia tridentata Nuttl; Lycopersicum esculentum Mill. ; Triticum compactum Host; Agropyron smithii Rydb. ; Salix pulchra Cham

    SciTech Connect

    Jackson, L.L.; Engleman, E.E.; Peard, J.L.

    1985-01-01

    Sulfur was determined in plants and lichens by combustion of the sample and infrared detection of evolved sulfur dioxide using an automated sulfur analyzer. Vanadium pentaoxide was used as a combustion accelerator. Pelletization of the sample prior to combustion was not found to be advantageous. Washing studies showed that leaching of sulfur was not a major factor in the sample preparation. The combustion-IR analysis usually gave higher sulfur content than the turbidimetric analysis as well as shorter analysis time. Relative standard deviations of less than 7% were obtained by the combustion-IR technique when sulfur levels in plant material range from 0.05 to 0.70%. Determination of sulfur in National Bureau of Standards botanical reference materials showed good agreement between the combustion-IR technique and other instrumental procedures. Seven NBS botanical reference materials were analyzed.

  17. The phylogenetic position of Acoela as revealed by the complete mitochondrial genome of Symsagittifera roscoffensis

    PubMed Central

    2010-01-01

    Background Acoels are simply organized unsegmented worms, lacking hindgut and anus. Several publications over recent years challenge the long-held view that acoels are early offshoots of the flatworms. Instead a basal position as sister group to all other bilaterian animals was suggested, mainly based on molecular evidence. This led to the view that features of acoels might reflect those of the last common ancestor of Bilateria, and resulted in several evo-devo studies trying to interpret bilaterian evolution using acoels as a proxy model for the "Urbilateria". Results We describe the first complete mitochondrial genome sequence of a member of the Acoela, Symsagittifera roscoffensis. Gene content and circular organization of the mitochondrial genome does not significantly differ from other bilaterian animals. However, gene order shows no similarity to any other mitochondrial genome within the Metazoa. Phylogenetic analyses of concatenated alignments of amino acid sequences from protein coding genes support a position of Acoela and Nemertodermatida as the sister group to all other Bilateria. Our data provided no support for a sister group relationship between Xenoturbellida and Acoela or Acoelomorpha. The phylogenetic position of Xenoturbella bocki as sister group to or part of the deuterostomes was also unstable. Conclusions Our phylogenetic analysis supports the view that acoels and nemertodermatids are the earliest divergent extant lineage of Bilateria. As such they remain a valid source for seeking primitive characters present in the last common ancestor of Bilateria. Gene order of mitochondrial genomes seems to be very variable among Acoela and Nemertodermatida and the groundplan for the metazoan mitochondrial genome remains elusive. More data are needed to interpret mitochondrial genome evolution at the base of Bilateria. PMID:20942955

  18. Combined large and small subunit ribosomal RNA phylogenies support a basal position of the acoelomorph flatworms.

    PubMed Central

    Telford, Maximilian J; Lockyer, Anne E; Cartwright-Finch, Chloë; Littlewood, D Timothy J

    2003-01-01

    The phylogenetic position of the phylum Platyhelminthes has been re-evaluated in the past decade by analysis of diverse molecular datasets. The consensus is that the Rhabditophora + Catenulida, which includes most of the flatworm taxa, are not primitively simple basal bilaterians but are related to coelomate phyla such as molluscs. The status of two other groups of acoelomate worms, Acoela and Nemertodermatida, is less clear. Although many characteristics unite these two groups, initial molecular phylogenetic studies placed the Nemertodermatida within the Rhabditophora, but placed the Acoela at the base of the Bilateria, distant from other flatworms. This contradiction resulted in scepticism about the basal position of acoels and led to calls for further data. We have sequenced large subunit ribosomal RNA genes from 13 rhabditophorans + catenulids, three acoels and one nemertodermatid, tripling the available data. Our analyses strongly support a basal position of both acoels and nemertodermatids. Alternative hypotheses are significantly less well supported by the data. We conclude that the Nemertodermatida and Acoela are basal bilaterians and, owing to their unique body plan and embryogenesis, should be recognized as a separate phylum, the Acoelomorpha. PMID:12803898

  19. Combined large and small subunit ribosomal RNA phylogenies support a basal position of the acoelomorph flatworms.

    PubMed

    Telford, Maximilian J; Lockyer, Anne E; Cartwright-Finch, Chloë; Littlewood, D Timothy J

    2003-05-22

    The phylogenetic position of the phylum Platyhelminthes has been re-evaluated in the past decade by analysis of diverse molecular datasets. The consensus is that the Rhabditophora + Catenulida, which includes most of the flatworm taxa, are not primitively simple basal bilaterians but are related to coelomate phyla such as molluscs. The status of two other groups of acoelomate worms, Acoela and Nemertodermatida, is less clear. Although many characteristics unite these two groups, initial molecular phylogenetic studies placed the Nemertodermatida within the Rhabditophora, but placed the Acoela at the base of the Bilateria, distant from other flatworms. This contradiction resulted in scepticism about the basal position of acoels and led to calls for further data. We have sequenced large subunit ribosomal RNA genes from 13 rhabditophorans + catenulids, three acoels and one nemertodermatid, tripling the available data. Our analyses strongly support a basal position of both acoels and nemertodermatids. Alternative hypotheses are significantly less well supported by the data. We conclude that the Nemertodermatida and Acoela are basal bilaterians and, owing to their unique body plan and embryogenesis, should be recognized as a separate phylum, the Acoelomorpha.

  20. ‘Appalachian Joy’ is a supernumery, white-bracted cultivar of cornus florida resistant to powdery mildew

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wholesale nursery industry in Tennessee contributes more than $200 million to the annual economy of the state and are in excess of $50 million annually for flowering dogwood (Cornus florida). Two fungal diseases, dogwood anthracnose and powdery mildew (Discula destructiva and Erysiphe pulchra, r...

  1. A Ploidy Difference Represents an Impassable Barrier for Hybridisation in Animals. Is There an Exception among Botiid Loaches (Teleostei: Botiidae)?

    PubMed Central

    Bohlen, Jörg; Šlechtová, Vendula; Šlechta, Vlastimil; Šlechtová, Vera; Sember, Alexandr; Ráb, Petr

    2016-01-01

    One of the most efficient mechanisms to keep animal lineages separate is a difference in ploidy level (number of whole genome copies), since hybrid offspring from parents with different ploidy level are functionally sterile. In the freshwater fish family Botiidae, ploidy difference has been held responsible for the separation of its two subfamilies, the evolutionary tetraploid Botiinae and the diploid Leptobotiinae. Diploid and tetraploid species coexist in the upper Yangtze, the Pearl River and the Red River basins in China. Interestingly, the species ‘Botia’ zebra from the Pearl River basin combines a number of morphological characters that otherwise are found in the diploid genus Leptobotia with morphological characters of the tetraploid genus Sinibotia, therefore the aim of the present study is to test weather ‘B.’ zebra is the result of a hybridisation event between species from different subfamilies with different ploidy level. A closer morphological examination indeed demonstrates a high similarity of ‘B.’ zebra to two co-occurring species, the diploid Leptobotia guilinensis and the tetraploid Sinibotia pulchra. These two species thus could have been the potential parental species in case of a hybrid origin of ‘B.’ zebra. The morphologic analysis further reveals that ‘B.’ zebra bears even the diagnostic characters of the genera Leptobotia (Leptobotiinae) and Sinibotia (Botiinae). In contrast, a comparison of six allozyme loci between ‘B.’ zebra, L. guilinensis and S. pulchra showed only similarities between ‘B.’ zebra and S. pulchra, not between ‘B.’ zebra and L. guilinensis. Six specimens of ‘B.’ zebra that were cytogenetically analysed were tetraploid with 4n = 100. The composition of the karyotype (18% metacentric, 18% submetacentric, 36% subtelocentric and 28% acrocentric chromosomes) differs from those of L. guilinensis (12%, 24%, 20% and 44%) and S. pulchra (20%, 26%, 28% and 26%), and cannot be obtained by any

  2. Distinctive features of cilia in metazoans and their significance for systematics.

    PubMed

    Tyler, S

    1979-01-01

    A comparative study of epidermal cilia in the Turbellaria and Nemertea has revealed features in these organelles that are specific to certain taxonomic groups. Turbellarians of the order Acoela, in particular, have a characteristic pattern of axonemal filament termination in the distal tips of their cilia and a characteristic ciliary rootlet system that is not seen in other turbellarian orders nor in other metazoans. Each epidermal cilium in acoels has a typical 9 + 2 axonemal pattern through the main part of its length, but near its distal tip there is an abrupt shelf-life narrowing at which filaments 4-7 terminate; filaments 1, 2, 8 and 9 continue into the thinner distal-most part of the shaft along with singlet microtubules from the axonemal center. The rootlet system in acoel cilia involves an interconnecting pattern with lateral connectives. The unique structure of these cilia has systematic and phylogenetic significance for the Acoela, and it is argued that ultrastructural characters in general, including characters of organelles, can be validly applied to the phylogeny and systematics of the Metazoa.

  3. Development and juvenile anatomy of the nemertodermatid Meara stichopi (Bock) Westblad 1949 (Acoelomorpha)

    PubMed Central

    2014-01-01

    Introduction Nemertodermatida is the sister group of the Acoela, which together form the Acoelomorpha, a taxon that comprises bilaterally symmetric, small aquatic worms. While there are several descriptions of the embryology of acoel species, descriptions of nemertodermatid development are scarce. To be able to reconstruct the ground pattern of the Acoelomorpha it is crucial to gain more information about the development of several nemertodermatid species. Here we describe the development of the nemertodermatid Meara stichopi using light and fluorescent microscopic methods. Results We have collected Meara stichopi during several seasons and reconstruct the complex annual reproductive cycle dependent on the sea cucumber Parastichopus tremulus. Using common fluorescent markers for musculature (BODIPY FL-phallacidin) and neurons (antibodies against FMRFamide, serotonin, tyrosinated-tubulin) and live imaging techniques, we followed embryogenesis which takes approximately 9–10 weeks. The cleavage pattern is stereotypic up to the 16-cell stage. Ring- and longitudinal musculature start to develop during week 6, followed by the formation of the basiepidermal nervous system. The juvenile is hatching without mouth opening and has a basiepidermal nerve net with two dorsal neurite bundles and an anterior condensation. Conclusions The development of Meara stichopi differs from the development of Acoela in that it is less stereotypic and does not follow the typical acoel duet cleavage program. During late development Meara stichopi does not show a temporal anterior to posterior gradient during muscle and nervous system formation. PMID:25024737

  4. A Flatworm from the Genus Waminoa (Acoela: Convolutidae) Associated with Bleached Corals in Western Australia.

    PubMed

    Cooper, Crystal; Clode, Peta L; Thomson, Damian P; Stat, Michael

    2015-10-01

    A flatworm isolated from bleached colonies of the coral Coscinaraea marshae at Rottnest Island, Western Australia, is described using a combination of morphological and molecular systematics. This flatworm shares morphological features characteristic of the genus Waminoa (Acoelomorpha: Acoela), including the presence of two algal symbionts, but appears to have genital regions different from those of other described species of Waminoa. The design of new oligonucleotide primers enabled the amplification of partial 18S rDNA of the Rottnest Island acoel specimens, and phylogenetic analysis positioned them within Waminoa, confirming their placement in the genus. Furthermore, Waminoa specimens from Rottnest Island grouped into a sister clade to Waminoa brickneri, indicating that the morphological and genetic differences observed are most likely intraspecific and due to geographic variation. As such, we name these Rottnest Island specimens W. cf. brickneri, but highlight that key differences warrant further exploration before assignment to this species can be confirmed. This is the first acoel flatworm described from Western Australia and contributes to our understanding of the diversity and evolutionary relationship of the Acoela.

  5. Results of Surveys for Special Status Reptiles at the Site 300 Facilities of Lawrence Livermore National Laboratory

    SciTech Connect

    Woollett, J J

    2008-09-18

    The purpose of this report is to present the results of a live-trapping and visual surveys for special status reptiles at the Site 300 Facilities of Lawrence Livermore National Laboratory (LLNL). The survey was conducted under the authority of the Federal recovery permit of Swaim Biological Consulting (PRT-815537) and a Memorandum of Understanding issued from the California Department of Fish and Game. Site 300 is located between Livermore and Tracy just north of Tesla road (Alameda County) and Corral Hollow Road (San Joaquin County) and straddles the Alameda and San Joaquin County line (Figures 1 and 2). It encompasses portions of the USGS 7.5 minute Midway and Tracy quadrangles (Figure 2). Focused surveys were conducted for four special status reptiles including the Alameda whipsnake (Masticophis lateralis euryxanthus), the San Joaquin Whipsnake (Masticophis Hagellum ruddock), the silvery legless lizard (Anniella pulchra pulchra), and the California horned lizard (Phrynosoma coronanum frontale).

  6. Differential physiological responses of two congeneric scleractinian corals to mineral accretion and an electric field

    NASA Astrophysics Data System (ADS)

    Borell, E. M.; Romatzki, S. B. C.; Ferse, S. C. A.

    2010-03-01

    Despite increasing popularity of ‘electric’ reefs as a means for reef restoration, there is a distinct lack of quantitative evidence supporting the alleged benefits of this method. This study investigated the effects of an electric field versus an electric field in combination with a cathode on coral growth (skeletal extension) rates, coral survival, zooxanthella densities, chlorophyll a (chl a) concentrations, and chlorophyll fluorescence of Acropora pulchra and A. yongei. Coral transplants were grown for 4 months under three treatment conditions: (1) on an iron cathode, (2) on bamboo inside an electric field, or (3) on bamboo in the absence of an electric field. Contrary to predictions, coral growth rates of both species were highest inside the electric field and not on the cathode. Except for chl a concentrations, the cathode had a significant adverse effect on all measured variables for A. yongei but not for A. pulchra. Treatment had no effect on the survival of A. pulchra, while mortality rates of A. yongei were significantly higher in the presence of mineral accretion compared to the electric field and control. A. yongei on the cathode featured low zooxanthella densities, depressed electron transport rates (rETR) and maximum quantum yield ( F v/ F m), and reduced growth. By contrast, treatment had no effect on the fluorescence characteristics of A. pulchra, and zooxanthella densities were highest for corals on the cathode, coincident with high growth rates relative to the control. Overall, the data indicate that the proposed benefits of the mineral accretion technology to meet important objectives of reef rehabilitation with regard to colony growth and survival should be considered with caution.

  7. A comprehensive analysis of the microbial communities of healthy and diseased marine macroalgae and the detection of known and potential bacterial pathogens

    PubMed Central

    Zozaya-Valdes, Enrique; Egan, Suhelen; Thomas, Torsten

    2015-01-01

    Microorganisms are increasingly being recognized as the causative agents in the diseases of marine higher organisms, such as corals, sponges, and macroalgae. Delisea pulchra is a common, temperate red macroalga, which suffers from a bleaching disease. Two bacterial strains, Nautella italica R11 and Phaeobacter gallaeciensis LSS9, have been shown in vitro to cause bleaching symptoms, but previous work has failed to detect them during a natural bleaching event. To provide a link between in vitro observations and natural occurrences of the disease, we employ here deep-sequencing of the 16S rRNA gene to comprehensively analyze the community composition of healthy and diseased D. pulchra samples from two separate locations. We observed operational taxonomic units (OTUs) with 100% identity and coverage to the 16S RNA gene sequence of both in vitro pathogens, but only the OTU with similarity to strain LSS9 showed a statistically significant higher abundance in diseased samples. Our analysis also reveals the existence of other bacterial groups within the families Rhodobacteraceae and Flavobacteriaceae that strongly contribute to difference between diseased and healthy samples and thus these groups potentially contain novel macroalgal pathogens and/or saprophytes. Together our results provide evidence for the ecological relevance of one kind of in vitro pathogen, but also highlight the possibility that multiple opportunistic pathogens are involved in the bleaching disease of D. pulchra. PMID:25759688

  8. Demographic consequences of disease in a habitat-forming seaweed and impacts on interactions between natural enemies.

    PubMed

    Campbell, Alexandra H; Vergés, Adriana; Steinberg, Peter D

    2014-01-01

    Diseases affecting natural ecosystems are increasing in frequency and severity, but unless obviously catastrophic, the consequences of disease outbreaks are often overlooked, relative to other ecological processes (e.g., predation, competition). Disease can have profound effects on individuals and can also strongly influence interactions between infected hosts and their natural enemies. We investigated whether a novel bleaching disease affected the survival or performance of a habitat-forming red seaweed, Delisea pulchra. In addition, we investigated bidirectional, multipartite interactions between this seaweed host, its pathogens, and consumers. Although we found no negative impacts of disease on survival of D. pulchra, bleaching had substantial, negative consequences for affected individuals, including a dramatic drop in fecundity and a significant decrease in size. In the first direct demonstration of bacterial disease-mediated herbivory of seaweeds, herbivores generally preferred to consume bleached tissue in feeding trials, and we also found higher densities of herbivores on bleached than co-occurring, healthy algae at sites where herbivores were abundant. In a conceptually reciprocal test of the effects of herbivores on infection, we showed that simulated herbivory increased susceptibility to bleaching when algae were also exposed to cultures of a bacterial pathogen. Given the high proportions of D. pulchra affected by bleaching during peak periods, the impacts of this disease are likely to have important implications at the population level. This work highlights complex interactions between habitat-forming organisms and their natural enemies and further emphasizes the need to consider disease in ecological research.

  9. High resistance of Acropora coral gametes facing copper exposure.

    PubMed

    Puisay, Antoine; Pilon, Rosanne; Hédouin, Laetitia

    2015-02-01

    Pollution by heavy metals remains today an important threat to the health of humans and ecosystems, but there is still a paucity of data on the response of early life stages of key organisms. In this context, the present work assessed the fertilization success rate of two Acropora species (A. cytherea and A. pulchra) from the French Polynesia reefs exposed to six increasing copper concentrations in seawater. The two species showed a relatively high tolerance to copper (4h30-EC50 was 69.4 ± 4.8 μg L(-1) and 75.4 ± 6.4 μg L(-1) for A. cytherea and A. pulchra, respectively). As Cu concentration increases, an increasing proportion of deformed embryos was recorded (67.6% and 58.5% for A. cytherea and A. pulchra, respectively, at 220 μg Cu L(-1)). These results demonstrated thus, that high levels of copper could negatively impair the normal fertilization process of coral gametes and therefore alter the renewal of coral populations. Since the two Acropora species investigated in this study displayed a high resistance to copper, these results should be considered in the context of multiple stressors associated with climate change, where rising temperature or ocean acidification may significantly exacerbate copper toxicity.

  10. Mortality of exotic and native seeds in invaded and uninvaded habitats

    NASA Astrophysics Data System (ADS)

    Orrock, John L.; Hoisington-López, Jessica L.

    2009-09-01

    We examined seed survival in exotic- and native-dominated grasslands by placing seeds of a once-pervasive native grass species, Nassella pulchra, and two of the most common, widespread exotic grass species, Avena fatua and Bromus hordeaceus, in mesh bags in the field for 3 months. Compared to germination of unexposed seeds not placed in the field, exotic species experienced an approximately 40% reduction in viability, whereas the mortality experienced by the native species was <20%. Despite these differences, germination rates of exposed seeds were similar between native and exotic species because native N. pulchra seeds had lower initial viability prior to entering the seed bank. Seed mortality did not differ based on whether seeds were placed in habitats dominated by exotic or native grasses. Rather, our results suggest that re-establishment of native N. pulchra must focus on maximizing seed viability and survival, and that A. fatua and B. hordeaceus overcome relatively higher losses of viable seeds in the seed bank, potentially by producing large numbers of highly viable seeds.

  11. Observations on some unusual cell types in the enigmatic worm Xenoturbella (phylum uncertain).

    PubMed

    Israelsson, O

    2006-08-01

    The inner epithelially organized gastrodermis of the enigmatic simple worms of the genus Xenoturbella contains numerous partly phagocytized cells of two kinds, ciliated cells (PCCs) and muscle cells (PMCs). PCCs and PMCs have features of undifferentiated cells and do not derive from differentiated adult cells. Homology of phagocytized cells to pulsatile bodies in acoel and nemertodermatid flatworms is therefore rejected. The phagocytized cells might represent an hitherto unknown process of regeneration in Xenoturbella. The phagocytized material contains as much DNA as in all mitochondria and nuclei of the living cells. This is probably caused by lack of digestion of nucleic acids. The genome size of Xenoturbella bocki was determined. It has a C-value of about 0.55 pg.

  12. Soil Warming and Fertilization Effects on Growth Ring Widths of Arctic Shrubs - Application of a Novel Dendroecological Approach.

    NASA Astrophysics Data System (ADS)

    Iturrate Garcia, M.; Heijmans, M.; Schweingruber, F. H.; Niklaus, P. A.; Schaepman-Strub, G.

    2015-12-01

    Climate warming is suggested as the main driver of shrub expansion in arctic tundra regions. Shrub expansion may have consequences on biodiversity and climate, especially through its feedbacks with the energy budget. A better understanding of shrub expansion mechanisms, including growth rate patterns and stem anatomy changes, and their sensitivity to climate is needed in order to quantify related feedbacks. We present a novel dendroecological approach to determine the response of three arctic shrub species to increased soil temperature and nutrients. A full factorial block-design experiment was run for four years with a total of thirty plots. Six individuals of each species were sampled from each plot to test for treatment effects on growth rate and stem anatomy. We compared the ring width of the four years of experiment with the one of the four previous years. The preliminary results for Betula nana and Salix pulchra suggest a significant effect of the treatments on the growth ring width. The response is stronger in Salix pulchra than in Betula nana individuals. And, while Salix pulchra is more sensitive to the combined soil warming and fertilization treatment, Betula nana is to the fertilization treatment. We could not observe an effect of treatment on the stem anatomy, likely because bark thickness co-varies with age. We found significant positive correlations of cork, cortex and phloem thickness with xylem thickness (used as a proxy of age), and a significant difference in stem anatomy between species. The results suggest species-specific growth sensitivity to soil warming and nutrient enhancement. The use of experimental dendroecology by manipulating environmental conditions according to future climate scenarios and testing effects on shrub anatomy and annual growth will increase our understanding on shrub expansion mechanisms. Ongoing plant trait analysis and consecutive application in a 3D radiative transfer model will allow to quantify the feedback of

  13. Contribution of relative growth rate to root foraging by annual and perennial grasses from California oak woodlands.

    PubMed

    Aanderud, Zachary T; Bledsoe, Caroline S; Richards, James H

    2003-08-01

    Plants forage for nutrients by increasing their root length density (RLD) in nutrient-rich soil microsites through root morphological changes resulting in increased root biomass density (RBD), specific root length (SRL), or branching frequency (BF). It is commonly accepted that fast-growing species will forage more than slow-growing species. However, foraging responses may be due solely to differences in relative growth rates (RGR). There is little evidence, after the effects of RGR are removed, that the fast versus slow foraging theory is correct. In a pot study, we evaluated foraging of four grass species that differed in RGR: one fast-growing annual species, Bromus diandrus, two intermediate-growing species, annual Bromus hordeaceus and perennial Elymus glaucus, and one slow-growing perennial species, Nassella pulchra. We harvested plants either at a common time (plants varied in size) or at a common leaf number (plants similar size, surrogate for common biomass). By evaluating species at a common time, RGR influenced foraging. Conversely, by evaluating species at a common leaf number, foraging could be evaluated independent of RGR. When RGR was allowed to contribute to foraging (common time harvest), foraging and RGR were positively correlated. B. diandrus (fast RGR) foraged to a greater extent than did E. glaucus (intermediate RGR) and N. pulchra (slow RGR). E. glaucus (intermediate RGR) foraged to a greater extent than N. pulchra (slow RGR). Root growth within nutrient-rich microsites was due to significant increases in RBD, not to modifications of SRL or BF. However, when RGR was not allowed to influence foraging (common leaf number harvest), none of the four species significantly enhanced RLD in nutrient-rich compared to control microsites. This suggests that RGR strongly influenced the ability of these grass species to forage and also supports the need to evaluate plastic root traits independent of RGR.

  14. Ancestor–descendant relationships in evolution: origin of the extant pygmy right whale, Caperea marginata

    PubMed Central

    Tsai, Cheng-Hsiu; Fordyce, R. Ewan

    2015-01-01

    Ancestor–descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, †Miocaperea pulchra, and its sole living relative, the enigmatic pygmy right whale Caperea marginata, the latter represented by both adult and juvenile specimens. †Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR—the first so far identified within baleen whales (Cetacea: Mysticeti). The †Miocaperea–Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium. PMID:25589485

  15. Ancestor-descendant relationships in evolution: origin of the extant pygmy right whale, Caperea marginata.

    PubMed

    Tsai, Cheng-Hsiu; Fordyce, R Ewan

    2015-01-01

    Ancestor-descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, †Miocaperea pulchra, and its sole living relative, the enigmatic pygmy right whale Caperea marginata, the latter represented by both adult and juvenile specimens. †Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR-the first so far identified within baleen whales (Cetacea: Mysticeti). The †Miocaperea-Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium.

  16. A taxonomic study of the beetle cockroaches (Diploptera Saussure) from China, with notes on the genus and species worldwide (Blattodea: Blaberidae: Diplopterinae).

    PubMed

    Li, Xinran; Wang, Zongqing

    2015-09-14

    Four taxa of beetle cockroaches (Diploptera Saussure, 1864) from South China are described and illustrated, viz., two new species D. elliptica sp. n. and D. naevus sp. n., one new subspecies D. nigrescens guani subsp. n. and one widespread known species D. punctata (Eschscholtz, 1822). The genus and known species from around the world are discussed based on types and other specimens. D. pulchra Anisyutkin, 2007 is now regarded as a junior synonym of D. bicolor Hanitsch, 1925. Whether the populations of D. punctata represent or not different species needs to be studied in the future. A key, a distribution map, and photos of species are provided.

  17. Two new species of Acrocephalomyia Ibáñez-Bernal & Hernández-Ortiz, 2012 from Brazil (Diptera: Ropalomeridae) and a key to known species.

    PubMed

    Alvim, Edgar; Ale-Rocha, Rosaly

    2016-01-01

    Two new species of Acrocephalomyia Ibáñez-Bernal & Hernández-Ortiz (Diptera, Ropalomeridae) are described. The genus currently includes three species, the type species from Costa Rica, Acrocephalomyia zumbadoi Ibáñez-Bernal & Hernández-Ortiz, and two new species from Brazil herein described, A. torulosa sp. nov., (State of Mato Grosso do Sul, Midwest) and A. pulchra sp. nov. (State of Amazonas, North). A key for the known species of Acrocephalomyia is given and characters of the male terminalia are described and discussed for the first time, with special attention to the "epiphallus". PMID:27395862

  18. Coupled long-term summer warming and deeper snow alters species composition and stimulates gross primary productivity in tussock tundra.

    PubMed

    Leffler, A Joshua; Klein, Eric S; Oberbauer, Steven F; Welker, Jeffrey M

    2016-05-01

    Climate change is expected to increase summer temperature and winter precipitation throughout the Arctic. The long-term implications of these changes for plant species composition, plant function, and ecosystem processes are difficult to predict. We report on the influence of enhanced snow depth and warmer summer temperature following 20 years of an ITEX experimental manipulation at Toolik Lake, Alaska. Winter snow depth was increased using snow fences and warming was accomplished during summer using passive open-top chambers. One of the most important consequences of these experimental treatments was an increase in active layer depth and rate of thaw, which has led to deeper drainage and lower soil moisture content. Vegetation concomitantly shifted from a relatively wet system with high cover of the sedge Eriophorum vaginatum to a drier system, dominated by deciduous shrubs including Betula nana and Salix pulchra. At the individual plant level, we observed higher leaf nitrogen concentration associated with warmer temperatures and increased snow in S. pulchra and B. nana, but high leaf nitrogen concentration did not lead to higher rates of net photosynthesis. At the ecosystem level, we observed higher GPP and NEE in response to summer warming. Our results suggest that deeper snow has a cascading set of biophysical consequences that include a deeper active layer that leads to altered species composition, greater leaf nitrogen concentration, and higher ecosystem-level carbon uptake.

  19. Does beach nourishment have long-term effects on intertidal macroinvertebrate species abundance?

    NASA Astrophysics Data System (ADS)

    Leewis, Lies; van Bodegom, Peter M.; Rozema, Jelte; Janssen, Gerard M.

    2012-11-01

    Coastal squeeze is the largest threat for sandy coastal areas. To mitigate seaward threats, erosion and sea level rise, sand nourishment is commonly applied. However, its long-term consequences for macroinvertebrate fauna, critical to most ecosystem services of sandy coasts, are still unknown. Seventeen sandy beaches - nourished and controls - were sampled along a chronosequence to investigate the abundance of four dominant macrofauna species and their relations with nourishment year and relevant coastal environmental variables. Dean's parameter and latitude significantly explained the abundance of the spionid polychaete Scolelepis squamata, Beach Index (BI), sand skewness, beach slope and latitude explained the abundance of the amphipod Haustorius arenarius and Relative Tide Range (RTR), recreation and sand sorting explained the abundance of Bathyporeia sarsi. For Eurydice pulchra, no environmental variable explained its abundance. For H. arenarius, E. pulchra and B. sarsi, there was no relation with nourishment year, indicating that recovery took place within a year after nourishment. Scolelepis squamata initially profited from the nourishment with "over-recolonisation". This confirms its role as an opportunistic species, thereby altering the initial community structure on a beach after nourishment. We conclude that the responses of the four dominant invertebrates studied in the years following beach nourishment are species specific. This shows the importance of knowing the autecology of the sandy beach macroinvertebrate fauna in order to be able to mitigate the effects of beach nourishment and other environmental impacts.

  20. Coupled long-term summer warming and deeper snow alters species composition and stimulates gross primary productivity in tussock tundra.

    PubMed

    Leffler, A Joshua; Klein, Eric S; Oberbauer, Steven F; Welker, Jeffrey M

    2016-05-01

    Climate change is expected to increase summer temperature and winter precipitation throughout the Arctic. The long-term implications of these changes for plant species composition, plant function, and ecosystem processes are difficult to predict. We report on the influence of enhanced snow depth and warmer summer temperature following 20 years of an ITEX experimental manipulation at Toolik Lake, Alaska. Winter snow depth was increased using snow fences and warming was accomplished during summer using passive open-top chambers. One of the most important consequences of these experimental treatments was an increase in active layer depth and rate of thaw, which has led to deeper drainage and lower soil moisture content. Vegetation concomitantly shifted from a relatively wet system with high cover of the sedge Eriophorum vaginatum to a drier system, dominated by deciduous shrubs including Betula nana and Salix pulchra. At the individual plant level, we observed higher leaf nitrogen concentration associated with warmer temperatures and increased snow in S. pulchra and B. nana, but high leaf nitrogen concentration did not lead to higher rates of net photosynthesis. At the ecosystem level, we observed higher GPP and NEE in response to summer warming. Our results suggest that deeper snow has a cascading set of biophysical consequences that include a deeper active layer that leads to altered species composition, greater leaf nitrogen concentration, and higher ecosystem-level carbon uptake. PMID:26747269

  1. Multiple pathways for invasion of anurans on a Pacific island

    USGS Publications Warehouse

    Christy, M.T.; Savidge, J.A.; Rodda, G.H.

    2007-01-01

    Since 1937, thirteen species of non-indigenous anurans have made their way to Guam. Of these, at least six have established breeding populations. Various pathways led to the introduction of these species to the island. The only anuran intentionally introduced was Chaunus marinus (formerly Bufo marinus), which was brought to Guam as a biocontrol agent. Kaloula picta, K. pulchra, Polypedates leucomystax, and probably Litoria fallax arrived as stowaways via maritime or air-transport vessels. Eleutherodactylus coqui and Euhyas (formerly Eleutherodactylus) planirostris appear to have entered Guam through the horticultural trade. Specimens of Pseudacris regilla were found among agricultural products and Christmas trees. Five species have been transported to Guam via the aquacultural trade. The importation of tilapia, milkfish, and white shrimp from China, Hong Kong, Taiwan, and the Philippines was associated with the introduction to Guam of Fejervarya cancrivora, F. limnocharis sensu lato, Microhyla pulchra, Polypedates megacephalus, and Sylvirana guentheri (formerly Rana guentheri). Presently, no quarantine or containment guidelines have been established for Guam's aquacultural industry. ?? 2007 The Authors.

  2. VarR controls colonization and virulence in the marine macroalgal pathogen Nautella italica R11

    PubMed Central

    Gardiner, Melissa; Fernandes, Neil D.; Nowakowski, Dennis; Raftery, Mark; Kjelleberg, Staffan; Zhong, Ling; Thomas, Torsten; Egan, Suhelen

    2015-01-01

    There is increasing evidence to suggest that macroalgae (seaweeds) are susceptible to infectious disease. However, to date, little is known about the mechanisms that facilitate the colonization and virulence of microbial seaweed pathogens. One well-described example of a seaweed disease is the bleaching of the red alga Delisea pulchra, which can be caused by the bacterium Nautella italica R11, a member of the Roseobacter clade. This pathogen contains a unique luxR-type gene, varR, which we hypothesize controls its colonization and virulence. We show here that a varR knock-out strain is deficient in its ability to cause disease in D. pulchra and is defective in biofilm formation and attachment to a common algal polysaccharide. Moreover complementation of the varR gene in trans can restore these functions to the wild type levels. Proteomic analysis of bacterial cells in planktonic and biofilm growth highlight the potential importance of nitrogen scavenging, mobilization of energy reserves, and stress resistance in the biofilm lifestyle of N. italica R11. Moreover, we show that VarR regulates the expression of a specific subset of biofilm-associated proteins. Taken together these data suggest that VarR controls colonization and persistence of N. italica R11 on the surface of a macroalgal host and that it is an important regulator of virulence. PMID:26528274

  3. Four newly recorded free-living marine nematodes (Comesomatidae) from the East China Sea

    NASA Astrophysics Data System (ADS)

    Hua, Er; Zhang, Zhinan

    2007-01-01

    Three species in genus Sabatieria and one in genus Cervonema from the East China Sea were recorded. S. breviseta is characterized by uniformly punctuated coarse dots, large amphids of 5.5 turns (♂) and prominent gubernaculum median piece. The characters of S. breviseta agree quite well with the European original descriptions and only differ in the male amphid turns (5.5 vs. 4.0 turns) and unmodified preanal supplements (5-7 vs. 6). S. pulchra can be recognized by amphid 2.75 turns, irregularly arranged lateral dots, and the first three supplements anterior to the anus, which are more widely spaced than the following ones. The excretory system of S. breviseta and S. pulchra shows sexual dimorphism. S. celtica is defined by amphids 2.00-2.25 turns, weakly developed pharyngeal bulb, curved apophyses and 12-13 conspicuous supplements. C. deltensis is characterized by amphids 4.75 turns, ovate pharyngeal posterior bulb, sperm dimorphism, 7 thin preanal supplements, and long tail cylindrical portion (50%-53% of tail length). All the three Sabatieria species are for the first time recorded in Chinese waters. C. deltensis was originally isolated from the Bohai Sea and Yellow Sea and newly recorded in the East China Sea.

  4. Recent records of alien anurans on the Pacific Island of Guam

    USGS Publications Warehouse

    Christy, M.T.; Clark, C.S.; Gee, D.E.; Vice, D.; Vice, D.S.; Warner, M.P.; Tyrrell, C.L.; Rodda, G.H.; Savidge, J.A.

    2007-01-01

    Eight anuran species were recorded for the first time in Guam in the period May 2003-December 2005, all apparently the result of arrivals to the island since 2000. Three of the eight species (Rana guentheri, Polypedates megacephalus, and Eleutherodactylus planirostris) had well-established breeding populations by 2005. A further three (Fejevarya cf. livinocharis, Fejervarya cancrivora, and Microhyla pulchra) were recorded from a number of individuals, but it is not known whether these species have established breeding populations. Two species (Kaloula pulchra and Eleutherodactylus coqui) appear to be incidental transportations to the island that have not established. Before 2003, five anuran species, all introductions, had been recorded from Guam. Three of these, Polypedates leucomystax, Pseudacris regilla, and Kaloula picta, were detected on Guam in incoming cargo but destroyed. Two species established: Bufo marinus was deliberately introduced and the Australian hylid Litoria fallax was probably an accidental introduction. Successful establishment of anurans on Guam has increased the risk of frog introductions to nearby islands. By providing additional food sources for the brown tree snake (Boiga irregularis), anuran introductions have increased the chance that B. irregularis might substantially increase in numbers and in turn increase the risk of the snake being accidentally transported to other islands. ?? 2007 by University of Hawai'i Press All rights reserved.

  5. Differential ecophysiological response of deciduous shrubs and a graminoid to long-term experimental snow reductions and additions in moist acidic tundra, Northern Alaska.

    PubMed

    Pattison, Robert R; Welker, Jeffrey M

    2014-02-01

    Changes in winter precipitation that include both decreases and increases in winter snow are underway across the Arctic. In this study, we used a 14-year experiment that has increased and decreased winter snow in the moist acidic tussock tundra of northern Alaska to understand impacts of variation in winter snow depth on summer leaf-level ecophysiology of two deciduous shrubs and a graminoid species, including: instantaneous rates of leaf gas exchange, and δ(13)C, δ(15)N, and nitrogen (N) concentrations of Betula nana, Salix pulchra, and Eriophorum vaginatum. Leaf-level measurements were complemented by measurements of canopy leaf area index (LAI) and depth of thaw. Reductions in snow lowered summer leaf photosynthesis, conductance, and transpiration rates by up to 40% compared to ambient and deep snow conditions for Eriophorum vaginatum, and reduced Salix pulchra conductance and transpiration by up to 49%. In contrast, Betula nana exhibited no changes in leaf gas exchange in response to lower or deeper snow. Canopy LAI increased with added snow, while reduced winter snow resulted in lower growing season soil temperatures and reduced thaw depths. Our findings indicate that the spatial and temporal variability of future snow depth will have individualistic consequences for leaf-level C fixation and water flux by tundra species, and that these responses will be manifested over the longer term by changes in canopy traits, depth of thaw, soil C and N processes, and trace gas (CO2 and H2O) exchanges between the tundra and the atmosphere.

  6. Evolution of basal deuterostome nervous systems.

    PubMed

    Holland, Linda Z

    2015-02-15

    Understanding the evolution of deuterostome nervous systems has been complicated by the by the ambiguous phylogenetic position of the Xenocoelomorpha (Xenoturbellids, acoel flat worms, nemertodermatids), which has been placed either as basal bilaterians, basal deuterostomes or as a sister group to the hemichordate/echinoderm clade (Ambulacraria), which is a sister group of the Chordata. None of these groups has a single longitudinal nerve cord and a brain. A further complication is that echinoderm nerve cords are not likely to be evolutionarily related to the chordate central nervous system. For hemichordates, opinion is divided as to whether either one or none of the two nerve cords is homologous to the chordate nerve cord. In chordates, opposition by two secreted signaling proteins, bone morphogenetic protein (BMP) and Nodal, regulates partitioning of the ectoderm into central and peripheral nervous systems. Similarly, in echinoderm larvae, opposition between BMP and Nodal positions the ciliary band and regulates its extent. The apparent loss of this opposition in hemichordates is, therefore, compatible with the scenario, suggested by Dawydoff over 65 years ago, that a true centralized nervous system was lost in hemichordates.

  7. [Molecular phylogeny of gastrotricha based on 18S rRNA genes comparison: rejection of hypothesis of relatedness with nematodes].

    PubMed

    Petrov, N B; Pegova, A N; Manylov, O G; Vladychenskaia, N S; Miuge, N S; Aleshin, V V

    2007-01-01

    Gastrotrichs are meiobenthic free-living aquatic worms whose phylogenetic and intra-group relationships remain unclear despite some attempts to resolve them on the base of morphology or molecules. In this study we analysed complete sequences of the 18S rRNA gene of 15 taxa (8 new and 7 published) to test numerous hypotheses on gastrotrich phylogeny and to verify whether controversial interrelationships from previous molecular data could be due to the short region available for analysis and the poor taxa sampling. Data were analysed using both maximum likelihood and Bayesian inference. Results obtained suggest that gastrotrichs, together with Gnathostomulida, Plathelminthes, Syndermata (Rotifera + Acanthocephala), Nemertea and Lophotrochozoa, comprise a clade Spiralia. Statistical tests reject phylogenetic hypotheses regarding Gastrotricha as close relatives of Nematoda and other Ecdysozoa or placing them at the base of bilaterian tree close to acoels and nemertodermatides. Within Gastrotricha, Chaetonotida and Macrodasyida comprise two well supported clades. Our analysis confirmed the monophyly of the Chaetonotidae and Xenotrichulidae within Chaetonida as well as Turbanellidae and Thaumastodermatidae within Macrodasyida. Mesodasys is a sister group of the Turbanellidae, and Lepidodasyidae appears to be a polyphyletic group as Cephalodasys forms a separate lineage at the base of macrodasyids, whereas Lepidodasys groups with Neodasys between Thaumastodermatidae and Turbanellidae. To infer a more reliable Gastrotricha phylogeny many species and additional genes should be involved in future analyses. PMID:17685227

  8. Expression pattern of Piwi-like genes in adult Myzostoma cirriferum (Annelida).

    PubMed

    Weigert, Anne; Helm, Conrad; Hausen, Harald; Zakrzewski, Anne-C; Bleidorn, Christoph

    2013-09-01

    Piwi-like genes are a subgroup of Argonaute genes which participate as gene regulators by gene silencing. In most bilaterians, such as mouse, human, insects, and zebrafish, their expression is mostly limited to gonadal stem cells. But there are some striking exceptions to this pattern; flatworms and acoels also express Piwi-like genes in somatic stem cells, due to their unique replacement system. Annelid species like Capitella teleta and Platynereis dumerilii express these genes in cells of the posterior growth zone as well as in gonadal stem cells. To investigate the expression pattern of Piwi-like genes in another annelid, we established in situ hybridization for adult Myzostoma cirriferum. Piwi-like gene transcripts recovered in an mRNA-seq library of pooled adult stages of M. cirriferum were expanded using RACE PCR, cloned and sequenced. ML analysis confirmed the identity of both transcripts as part of the Piwi1-like or Piwi2-like subfamily of Argonaute proteins. The results of in situ hybridization studies show that the expression of both Piwi-like genes, Mc-Piwi1 and Mc-Piwi2, is clearly located only in gonadal stem cells, and as such we did not find any evidence for the existence of a posterior growth zone nor expression in somatic stem cells.

  9. Genealogical correspondence of a forebrain centre implies an executive brain in the protostome-deuterostome bilaterian ancestor.

    PubMed

    Wolff, Gabriella H; Strausfeld, Nicholas J

    2016-01-01

    Orthologous genes involved in the formation of proteins associated with memory acquisition are similarly expressed in forebrain centres that exhibit similar cognitive properties. These proteins include cAMP-dependent protein kinase A catalytic subunit (PKA-Cα) and phosphorylated Ca(2+)/calmodulin-dependent protein kinase II (pCaMKII), both required for long-term memory formation which is enriched in rodent hippocampus and insect mushroom bodies, both implicated in allocentric memory and both possessing corresponding neuronal architectures. Antibodies against these proteins resolve forebrain centres, or their equivalents, having the same ground pattern of neuronal organization in species across five phyla. The ground pattern is defined by olfactory or chemosensory afferents supplying systems of parallel fibres of intrinsic neurons intersected by orthogonal domains of afferent and efferent arborizations with local interneurons providing feedback loops. The totality of shared characters implies a deep origin in the protostome-deuterostome bilaterian ancestor of elements of a learning and memory circuit. Proxies for such an ancestral taxon are simple extant bilaterians, particularly acoels that express PKA-Cα and pCaMKII in discrete anterior domains that can be properly referred to as brains. PMID:26598732

  10. Biodiversity Meets Neuroscience: From the Sequencing Ship (Ship-Seq) to Deciphering Parallel Evolution of Neural Systems in Omic's Era.

    PubMed

    Moroz, Leonid L

    2015-12-01

    The origins of neural systems and centralized brains are one of the major transitions in evolution. These events might occur more than once over 570-600 million years. The convergent evolution of neural circuits is evident from a diversity of unique adaptive strategies implemented by ctenophores, cnidarians, acoels, molluscs, and basal deuterostomes. But, further integration of biodiversity research and neuroscience is required to decipher critical events leading to development of complex integrative and cognitive functions. Here, we outline reference species and interdisciplinary approaches in reconstructing the evolution of nervous systems. In the "omic" era, it is now possible to establish fully functional genomics laboratories aboard of oceanic ships and perform sequencing and real-time analyses of data at any oceanic location (named here as Ship-Seq). In doing so, fragile, rare, cryptic, and planktonic organisms, or even entire marine ecosystems, are becoming accessible directly to experimental and physiological analyses by modern analytical tools. Thus, we are now in a position to take full advantages from countless "experiments" Nature performed for us in the course of 3.5 billion years of biological evolution. Together with progress in computational and comparative genomics, evolutionary neuroscience, proteomic and developmental biology, a new surprising picture is emerging that reveals many ways of how nervous systems evolved. As a result, this symposium provides a unique opportunity to revisit old questions about the origins of biological complexity.

  11. Marine zooplankton studies in Brazil: a brief evaluation and perspectives.

    PubMed

    Lopes, Rubens M

    2007-09-01

    Marine zooplankton research in Brazil has been primarily descriptive, with most studies focusing on community structure analysis and related issues. The composition and spatial distribution of several taxonomic groups are currently well known, although less-abundant and small-sized taxa as well as initial stages of almost all species have received little attention. Some numerically important taxa such as heterotrophic protists, ctenophores, acoel turbellarians and ostracods remain virtually unstudied. Large sectors of the continental shelf have not been sampled in detail, particularly those areas influenced by the North Brazil Current (5 degrees N-15 degrees S). Zooplankton abundance and biomass in offshore waters have seldom been quantified, and information on the distribution and vertical migration of meso- and bathypelagic species are lacking. Additional faunistic assessments must target those less-studied taxa and geographical locations. However, priority in ecological studies should be given to process-oriented investigations aimed at understanding the mechanisms controlling zooplankton distribution, trophic interactions within pelagic food webs and production cycles in relation to the physical environment. An effort should be made to incorporate state-of-the-art sampling technology and analytical methods into future research projects.

  12. An integrated view of precambrian eumetazoan evolution.

    PubMed

    Davidson, E H; Erwin, D H

    2009-01-01

    The eumetazoan clade of modern animals includes cnidarians, acoels, deuterostomes, and protostomes. Stem group eumetazoans evolved in the late Neoproterozoic, possibly before the Marinoan glaciation, according to a variety of different kinds of evidence. Here, we combine this evidence, including paleontological observations, results from molecular and morphological phylogeny, and paleoecological considerations, with deductions from the organization of the gene regulatory networks that underlie development of the bilaterian body plan. Eumetazoan body parts are morphologically complex in detail, and modern knowledge of gene regulatory network structure shows that the control circuitry required for their development is hierarchical and multilayered. Among the consequences is that the kernels of the networks that control the early allocation of spatial developmental fate canalize the possibilities of downstream evolutionary change, a mechanism that can account for the appearance of distinct clades in early animal evolution. We reconstruct preeumetazoan network organization and consider the process by which the eumetazoan regulatory apparatus might have been assembled. A strong conclusion is that the evolutionary process generating the genomic programs responsible for developmental formulation of basic eumetazoan body plans was in many ways very different from the evolutionary changes that can be observed at the species level in modern animals. PMID:20375317

  13. Neuroglobins, pivotal proteins associated with emerging neural systems and precursors of metazoan globin diversity.

    PubMed

    Lechauve, Christophe; Jager, Muriel; Laguerre, Laurent; Kiger, Laurent; Correc, Gaëlle; Leroux, Cédric; Vinogradov, Serge; Czjzek, Mirjam; Marden, Michael C; Bailly, Xavier

    2013-03-01

    Neuroglobins, previously thought to be restricted to vertebrate neurons, were detected in the brain of a photosymbiotic acoel, Symsagittifera roscoffensis, and in neurosensory cells of the jellyfish Clytia hemisphaerica. For the neuroglobin of S. roscoffensis, a member of a lineage that originated either at the base of the bilateria or of the deuterostome clade, we report the ligand binding properties, crystal structure at 2.3 Å, and brain immunocytochemical pattern. We also describe in situ hybridizations of two neuroglobins specifically expressed in differentiating nematocytes (neurosensory cells) and in statocytes (ciliated mechanosensory cells) of C. hemisphaerica, a member of the early branching animal phylum cnidaria. In silico searches using these neuroglobins as queries revealed the presence of previously unidentified neuroglobin-like sequences in most metazoan lineages. Because neural systems are almost ubiquitous in metazoa, the constitutive expression of neuroglobin-like proteins strongly supports the notion of an intimate association of neuroglobins with the evolution of animal neural systems and hints at the preservation of a vitally important function. Neuroglobins were probably recruited in the first protoneurons in early metazoans from globin precursors. Neuroglobins were identified in choanoflagellates, sponges, and placozoans and were conserved during nervous system evolution. Because the origin of neuroglobins predates the other metazoan globins, it is likely that neuroglobin gene duplication followed by co-option and subfunctionalization led to the emergence of globin families in protostomes and deuterostomes (i.e. convergent evolution).

  14. The nervous system of Xenacoelomorpha: a genomic perspective.

    PubMed

    Perea-Atienza, Elena; Gavilán, Brenda; Chiodin, Marta; Abril, Josep F; Hoff, Katharina J; Poustka, Albert J; Martinez, Pedro

    2015-02-15

    Xenacoelomorpha is, most probably, a monophyletic group that includes three clades: Acoela, Nemertodermatida and Xenoturbellida. The group still has contentious phylogenetic affinities; though most authors place it as the sister group of the remaining bilaterians, some would include it as a fourth phylum within the Deuterostomia. Over the past few years, our group, along with others, has undertaken a systematic study of the microscopic anatomy of these worms; our main aim is to understand the structure and development of the nervous system. This research plan has been aided by the use of molecular/developmental tools, the most important of which has been the sequencing of the complete genomes and transcriptomes of different members of the three clades. The data obtained has been used to analyse the evolutionary history of gene families and to study their expression patterns during development, in both space and time. A major focus of our research is the origin of 'cephalized' (centralized) nervous systems. How complex brains are assembled from simpler neuronal arrays has been a matter of intense debate for at least 100 years. We are now tackling this issue using Xenacoelomorpha models. These represent an ideal system for this work because the members of the three clades have nervous systems with different degrees of cephalization; from the relatively simple sub-epithelial net of Xenoturbella to the compact brain of acoels. How this process of 'progressive' cephalization is reflected in the genomes or transcriptomes of these three groups of animals is the subject of this paper.

  15. [Molecular phylogeny of gastrotricha based on 18S rRNA genes comparison: rejection of hypothesis of relatedness with nematodes].

    PubMed

    Petrov, N B; Pegova, A N; Manylov, O G; Vladychenskaia, N S; Miuge, N S; Aleshin, V V

    2007-01-01

    Gastrotrichs are meiobenthic free-living aquatic worms whose phylogenetic and intra-group relationships remain unclear despite some attempts to resolve them on the base of morphology or molecules. In this study we analysed complete sequences of the 18S rRNA gene of 15 taxa (8 new and 7 published) to test numerous hypotheses on gastrotrich phylogeny and to verify whether controversial interrelationships from previous molecular data could be due to the short region available for analysis and the poor taxa sampling. Data were analysed using both maximum likelihood and Bayesian inference. Results obtained suggest that gastrotrichs, together with Gnathostomulida, Plathelminthes, Syndermata (Rotifera + Acanthocephala), Nemertea and Lophotrochozoa, comprise a clade Spiralia. Statistical tests reject phylogenetic hypotheses regarding Gastrotricha as close relatives of Nematoda and other Ecdysozoa or placing them at the base of bilaterian tree close to acoels and nemertodermatides. Within Gastrotricha, Chaetonotida and Macrodasyida comprise two well supported clades. Our analysis confirmed the monophyly of the Chaetonotidae and Xenotrichulidae within Chaetonida as well as Turbanellidae and Thaumastodermatidae within Macrodasyida. Mesodasys is a sister group of the Turbanellidae, and Lepidodasyidae appears to be a polyphyletic group as Cephalodasys forms a separate lineage at the base of macrodasyids, whereas Lepidodasys groups with Neodasys between Thaumastodermatidae and Turbanellidae. To infer a more reliable Gastrotricha phylogeny many species and additional genes should be involved in future analyses.

  16. Morphological and molecular study of the poorly known species Pseudanisakis rajae (Yamaguti, 1941) (Nematoda: Acanthocheilidae) from elasmobranchs in the Yellow Sea and Taiwan Strait off the coast of China.

    PubMed

    Li, Liang; Gibson, David I; Liu, Yuan-Yuan; Zhang, Lu-Ping

    2012-02-01

    Ascaridoid nematodes identified as Pseudanisakis rajae (Yamaguti, 1941) were collected from the skates Bathyraja smirnovi (Soldatov & Pavlenko), Okamejei kenojei (Müller & Henle) and Raja pulchra Liu (Rajiformes: Rajidae) in the Yellow Sea and Taiwan Strait off the coast of China. Their examination using light microscopy and, for the first time, scanning electron microscopy revealed erroneous and previously unreported morphological features, necessitating the redescription of this little known species. In addition, specimens of P. rajae collected from the three different hosts were characterised using molecular methods by sequencing and analysing the internal transcribed spacer (ITS) of the ribosomal DNA. These new morphological and molecular data enabled an updated diagnosis of this nematode and the presentation of an identification key to the species of Pseudanisakis Layman & Borovkova, 1926. PMID:22183921

  17. Ethnobotanical study of some Ghanaian anti-malarial plants.

    PubMed

    Asase, Alex; Oteng-Yeboah, Alfred A; Odamtten, George T; Simmonds, Monique S J

    2005-06-01

    An ethnobotanical study was conducted in the Wechiau Community Hippopotamus Sanctuary area in Ghana, through interviews and quadrate studies, to investigate the range and abundance of species used in the treatment of malaria. Forty-one species belonging to 17 families were encountered during the study. Of the 17 families studied Leguminosae and Anacardiaceae predominated in terms of number of species used to treat malaria. Eight plant species namely, Afraegle paniculata (Rutaceae), Haematostaphis barteri (Anacardiaceae), Indigo era pulchra (Leguminosae), Monanthotaxis sp. (Annonaceae), Ozoroa insignis (Anacardiaceae), Strychnos innocua (Loganiaceae), Strychnos spinosa (Loganiaceae) and Xeroderris stuhlmannii (Leguminosae) have not previously been documented for the treatment of malaria in Ghana. The results are discussed and recommendations made for future research to support the conservation and sustainable harvesting of the species reported to have medicinal properties. PMID:15894138

  18. A taxonomic catalogue of Japanese nemerteans (phylum Nemertea).

    PubMed

    Kajihara, Hiroshi

    2007-04-01

    A literature-based taxonomic catalogue of the nemertean species (Phylum Nemertea) reported from Japanese waters is provided, listing 19 families, 45 genera, and 120 species as valid. Applications of the following species names to forms previously recorded from Japanese waters are regarded as uncertain: Amphiporus cervicalis, Amphiporus depressus, Amphiporus lactifloreus, Cephalothrix filiformis, Cephalothrix linearis, Cerebratulus fuscus, Lineus vegetus, Lineus bilineatus, Lineus gesserensis, Lineus grubei, Lineus longifissus, Lineus mcintoshii, Nipponnemertes pulchra, Oerstedia venusta, Prostoma graecense, and Prostoma grande. The identities of the taxa referred to by the following four nominal species require clarification through future investigations: Cosmocephala japonica, Dicelis rubra, Dichilus obscurus, and Nareda serpentina. The nominal species established from Japanese waters are tabulated. In addition, a brief history of taxonomic research on Japanese nemerteans is reviewed.

  19. Long-term coral community records from Lugger Shoal on the terrigenous inner-shelf of the central Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Perry, C. T.; Smithers, S. G.; Johnson, K. G.

    2009-12-01

    Long-term (millennial timescale) records of coral community structure can be developed from the analysis of corals preserved in radiometrically dated reef cores. Here, we present such a record (based on six cores) from Lugger Shoal, a turbid zone, nearshore reef on the inner-shelf of the central Great Barrier Reef. Lugger Shoal initiated growth ~800 cal yBP. It is constructed of large in situ Porites bommies, between which a framework of coral rubble (dominated by Acropora pulchra, Montipora mollis, Galaxea fascicularis and Cyphastrea serailia) has accumulated. Reef accretion occurred under conditions of net long-term fine-grained, terrigenous sediment accumulation, and with a coral community dominated throughout by a consistent, but low diversity, suite of coral taxa. This dataset supports recent suggestions that nearshore coral communities that establish themselves under conditions that are already close to the thresholds for coral survival may be resilient to water quality deteriorations associated with human activities.

  20. New porcellioidean gastropods from early Devonian of Royal Creek area, Yukon Territory, Canada, with notes on their early phylogeny

    USGS Publications Warehouse

    Fryda, J.; Blodgett, R.B.; Lenz, A.C.; Manda, S.

    2008-01-01

    This paper presents a description of new gastropods belonging to the superfamily Porcellioidea (Vetigastropoda) from the richly diverse Lower Devonian gastropod fauna of the Road River Formation in the Royal Creek area, Yukon Territory. This fauna belongs to Western Canada Province of the Old World Realm. The Pragian species Porcellia (Porcellia) yukonensis n. sp. and Porcellia (Paraporcellia) sp. represent the oldest presently known members of subgenera Porcellia (Porcellia) and Porcellia (Paraporcellia). Their simple shell ornamentation fits well with an earlier described evolutionary trend in shell morphology of the Porcellinae. Late Pragian to early Emsian Perryconcha pulchra n. gen. and n. sp. is the first member of the Porcellioidea bearing a row of tremata on adult teleoconch whorls. The occurrence of this shell feature in the Porcellioidea is additional evidence that the evolution of the apertural slit was much more complicated than has been proposed in classical models of Paleozoic gastropod evolution. Copyright ?? 2008, The Paleontological Society.

  1. Tundra in the rain: differential vegetation responses to three years of experimentally doubled summer precipitation in Siberian shrub and Swedish bog tundra.

    PubMed

    Keuper, Frida; Parmentier, Frans-Jan W; Blok, Daan; van Bodegom, Peter M; Dorrepaal, Ellen; van Hal, Jurgen R; van Logtestijn, Richard S P; Aerts, Rien

    2012-01-01

    Precipitation amounts and patterns at high latitude sites have been predicted to change as a result of global climatic changes. We addressed vegetation responses to three years of experimentally increased summer precipitation in two previously unaddressed tundra types: Betula nana-dominated shrub tundra (northeast Siberia) and a dry Sphagnum fuscum-dominated bog (northern Sweden). Positive responses to approximately doubled ambient precipitation (an increase of 200 mm year(-1)) were observed at the Siberian site, for B. nana (30 % larger length increments), Salix pulchra (leaf size and length increments) and Arctagrostis latifolia (leaf size and specific leaf area), but none were observed at the Swedish site. Total biomass production did not increase at either of the study sites. This study corroborates studies in other tundra vegetation types and shows that despite regional differences at the plant level, total tundra plant productivity is, at least at the short or medium term, largely irresponsive to experimentally increased summer precipitation.

  2. The scarab beetle tribe Pentodontini (Coleoptera: Scarabaeidae: Dynastinae) of Colombia: taxonomy, natural history, and distribution.

    PubMed

    López-García, Margarita M; Gasca-Álvarez, Héctor J; Amat-García, Germán

    2015-11-27

    Pentodontini is the most diverse tribe of Dynastinae (Coleoptera: Scarabaeidae), and most of the genera are restricted to a single biogeographic region. In this work, the taxonomic composition of the Pentodontini in Colombia was determined, and genera and species were diagnosed based on external morphology and male genitalia. Records of 1,580 specimens from 31 departments and 398 localities in Colombia were obtained from 24 species in the genera Bothynus Hope, Denhezia Dechambre, Euetheola Bates, Hylobothynus Ohaus, Oxyligyrus Arrow, Parapucaya Prell, Pucaya Ohaus, and Tomarus Erichson. Oxyligyrus cayennensis Endrödi, Tomarus cicatricosus (Prell), and T. pullus (Prell) are reported for the first time from Colombia. Pucaya punctata Endrödi is reduced to synonymy with Pucaya pulchra Arrow. Possible changes in the classification of Denhezia Dechambre are discussed. Dichotomous keys are provided for Colombian genera and species. Taxonomic descriptions and distribution maps are included for all species.

  3. Graptemys pearlensis Ennen, Lovich, Kreiser, Selman, and Qualls 2010 – Pearl River Map Turtle

    USGS Publications Warehouse

    Ennen, Joshua R.; Lovich, Jeffrey E.; Jones, Robert L.; Rhodin, A. G. J.; Pritchard, P. C. H.; van Dijk, P. P.; Saumure, R.A.; Buhlmann, K.A.; Iverson, J.B.; Mittermeier, R.A.

    2016-01-01

    The Pearl River Map Turtle, Graptemys pearlensis (Family Emydidae), is a moderate-sized aquatic turtle endemic to the Pearl River drainage of Louisiana and Mississippi. This taxon has long been a cryptic species, as it was considered part of G. pulchra before 1992 and part of G. gibbonsi until 2010. Graptemys pearlensis exhibits sexual dimorphism, with adult females being considerably larger (carapace length to 295 mm) than adult males (CL to 121 mm). In the 1960s and 1970s, the species was commonly found in higher abundance than the sympatric G. oculifera, a federally listed species. However, due to habitat degradation and the precipitous decline of native mollusks, the species is now found in lower numbers than G. oculifera throughout much of its range. The current IUCN Red List status is Endangered; however, very little is known about the natural history and ecology of the species, which will make conservation efforts challenging.

  4. Tadpoles of three common anuran species from Thailand do not prey on mosquito larvae.

    PubMed

    Weterings, Robbie

    2015-12-01

    Tadpoles are often considered to be predators of mosquito larvae and are therefore beneficial for the control of certain disease vectors. Nevertheless, only a few species have actually been recorded to prey on mosquito larvae. The mosquito larvae predation rates of tadpoles of three common Thai anuran species (Bufo melanostictus, Kaloula pulchra and Hylarana raniceps) were experimentally tested. Tadpoles in varying developmental stages were used to assess a size/age effect on the predation rate. In addition, different instars of Culex quinquefasciatus were used in order to assess a prey size effect on the predation rates. All three species failed to show any evidence of mosquito larvae predation. Neither small nor large tadpoles fed on mosquito larvae. Prey size also did not affect predation. Although tadpoles do not feed on mosquito larvae, there may be other direct or indirect inter-specific interactions that adversely impact the development of larvae in shared habitats with tadpoles.

  5. Spatial polychaeta habitat potential mapping using probabilistic models

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Kuk; Oh, Hyun-Joo; Koo, Bon Joo; Ryu, Joo-Hyung; Lee, Saro

    2011-06-01

    The purpose of this study was to apply probabilistic models to the mapping of the potential polychaeta habitat area in the Hwangdo tidal flat, Korea. Remote sensing techniques were used to construct spatial datasets of ecological environments and field observations were carried out to determine the distribution of macrobenthos. Habitat potential mapping was achieved for two polychaeta species, Prionospio japonica and Prionospio pulchra, and eight control factors relating to the tidal macrobenthos distribution were selected. These included the intertidal digital elevation model (DEM), slope, aspect, tidal exposure duration, distance from tidal channels, tidal channel density, spectral reflectance of the near infrared (NIR) bands and surface sedimentary facies from satellite imagery. The spatial relationships between the polychaeta species and each control factor were calculated using a frequency ratio and weights-of-evidence combined with geographic information system (GIS) data. The species were randomly divided into a training set (70%) to analyze habitat potential using frequency ratio and weights-of-evidence, and a test set (30%) to verify the predicted habitat potential map. The relationships were overlaid to produce a habitat potential map with a polychaeta habitat potential (PHP) index value. These maps were verified by comparing them to surveyed habitat locations such as the verification data set. For the verification results, the frequency ratio model showed prediction accuracies of 77.71% and 74.87% for P. japonica and P. pulchra, respectively, while those for the weights-of-evidence model were 64.05% and 62.95%. Thus, the frequency ratio model provided a more accurate prediction than the weights-of-evidence model. Our data demonstrate that the frequency ratio and weights-of-evidence models based upon GIS analysis are effective for generating habitat potential maps of polychaeta species in a tidal flat. The results of this study can be applied towards

  6. Spawning times, reproductive compatibilities and genetic structuring in the Acropora aspera group: evidence for natural hybridization and semi-permeable species boundaries in corals.

    PubMed

    Van Oppen, Madeleine J H; Willis, Bette L; Van Rheede, Teun; Miller, David J

    2002-08-01

    Species boundaries among five sympatric coral species of the Indo-Pacific Acropora aspera group were examined by a combination of in vitro breeding trials, comparisons of spawning times and DNA sequence analysis of ribosomal DNA internal transcribed spacer (rDNA ITS) and 5.8S regions. The breeding trials showed that reproductive compatibility exists between at least some colonies of all the species pairs tested, suggesting a large potential for natural hybridization and introgression. The Acropora ITS regions exhibited extremely high levels of variability (up to approximately 62% for ITS1, approximately 11% for 5.8S and approximately 43% for ITS2), but most of the variation was shared among four of the five species, A. millepora, A. papillare, A. pulchra and A. spathulata, consistent with extensive introgression. Phylogenetic analyses did not resolve these four species as distinct clusters across a wide biogeographic region stretching from the southern Great Barrier Reef to Papua New Guinea. However, most colonies of the fifth species, A. aspera, constituted a distinct clade in phylogenetic analyses. This is consistent with our observations of a semi-permeable temporal barrier involving differences in spawning times between this and the other four species. Although the majority of colonies of all five species generally spawned within 90 min of each other, in two out of four years, gametes were absent prior to mass spawning episodes from at least some A. aspera colonies. Hence, our data suggest that transient reproductive barriers may be the result of year-to-year variation in the date of spawning and that this difference in spawning time contributes to the genetic structure detected among Acropora species in this group. Occasional leakage through the reproductive barrier was confirmed by the observation of A. aspera xA. pulchra F1 hybrids, identified based on additivity of ITS sequences.

  7. Silicoflagellate Fluxes in Cuenca Alfonso, Mexico During the 2002-2003 El Niño Event

    NASA Astrophysics Data System (ADS)

    Alvarez, I. G.; Martínez-López, A.; Silverberg, N.

    2007-05-01

    Changes in the circulation and water mass patterns in the Gulf of California are closely associated with changes in atmospheric circulation. At the interannual scale, such changes are associated with events like El Niño, which in the Gulf are characterized by greater penetration of tropical-equatorial water. Subsamples of sediment trap material, collected between January 2002 and February 2004 were examined with the aim of inferring average oceanographic conditions in Cuenca Alfonso, Bahia de La Paz and those during the relatively mild 2002- 03 El Niño. Analysis of the silicoflagellate data series reveals seasonal and interannual relationships between the silicoflagellate fluxes and the dynamics of the water column. Comparison of silicoflagellate fluxes with those of the diatom group indicate that the former represent 0-52% of their combined flux. Both silicate groups generally co-vary but show differences in intensity. Thirteen taxa made up the silicoflagellate species composition. The simultaneous occurrence of Dictyocha epiodon and Distephanus speculum with Dictyocha calida and Dictyocha californica during August 2002 to May 2003, indicated the presence of both California Current Water and Equatorial Surface Water in the area close to Cuenca Alfonso. This favored the increase, mainly in November-December, in the flux of the dominant species, Octactis pulchra (as high as 7 x 106 skeletons m-2 day-1). Spring, on the other hand, was notable for a drop in the total silicoflagellate flux, probably due to the influence of the El Niño event. The subsequent increase in species typical of warm water and the replacement of the dominant species (O. pulchra) by Dictyocha messanensis var messanensis, suggest that the effects of El Niño extended to the fall of 2003.

  8. Production, exportation and preservation of silicoflagellates in Alfonso Basin, Gulf of California

    NASA Astrophysics Data System (ADS)

    Martínez-López, Aída; Álvarez-Gómez, Irela G.; Pérez-Cruz, Ligia; Verdugo-Díaz, Gerardo; Villegas-Aguilera, María Magdalena

    2016-03-01

    Limited areas of sea floor have the physiochemical conditions that allow for the formation and preservation of high resolution (yearly or close to yearly) laminated sediments that can function as a historic proxy for past oceanographic and climate conditions. We evaluated and established the fidelity of the sedimentary record in recording these signals by analyzing silicoflagellates production, changes in species composition, skeletal settling and their subsequent burial in bottom sediments at Alfonso Basin. The data series from December 2005 to February 2008 showed similar tendencies in both the vertical flux and overlying euphotic zone (Zeu) production of silicoflagellates. Both series were numerically dominated by Octactis pulchra with maxima values being recorded for the mixed water column period. Observed differences occurred during the studied years in both magnitude and in flux composition. The presence of a mixed assemblage with (warm-temperate-cold) species such as Dictyocha fibula var. robusta, Dictyocha epiodon and Distephanus speculum could be explained by a synchronization of trends between a predominantly positive Pacific Decadal Oscillation and a positive North Pacific Gyre Oscillation climate phases that were the background conditions underlying the early 2006 through 2007 El Niño event. A Morisita's similarity index value of 97.5% between winter trap and Zeu samples combined with an annualized settling factor of 0.45, suggests that Alfonso Basin is a favorable settling environment for silicoflagellates. However, core-top sediments showed an attenuation of record fidelity (burial factor = 0.25) resulting in a modified record for the production and settling of skeletons. O. pulchra that were not preserved in sediments as the dominant species and with this removal, the signal was also lost of the highest silicoflagellate production season (Mixing-cyclonic eddy periods) from the sedimentary record of the Alfonso Basin.

  9. Variability in the effects of macroalgae on the survival and growth of corals: the consumer connection.

    PubMed

    Bulleri, Fabio; Couraudon-Réale, Marine; Lison de Loma, Thierry; Claudet, Joachim

    2013-01-01

    Shifts in dominance from corals to macroalgae are occurring in many coral reefs worldwide. Macroalgal canopies, while competing for space with coral colonies, may also form a barrier to herbivorous and corallivorous fish, offering protection to corals. Thus, corals could either suffer from enhanced competition with canopy-forming and understorey macroalgae or benefit from predator exclusion. Here, we tested the hypothesis that the effects of the brown, canopy-forming macroalga, Turbinaria ornata, on the survival and growth of corals can vary according to its cover, to the presence or absence of herbivorous and corallivorous fish and to the morphological types of corals. Over a period of 66 days, two coral species differing in growth form, Acropora pulchra and Porites rus, were exposed to three different covers of T. ornata (absent versus medium versus high), in the presence or absence of fish. Irrespective of the cover of T. ornata, fish exclusion reduced mortality rates of A. pulchra. Following fish exclusion, a high cover of T. ornata depressed the growth of this branched coral, whilst it had no effect when fish species were present. P. rus suffered no damage from corallivorous fish, but its growth was decreased by high covers of T. ornata, irrespective of the presence or absence of fish. These results show that negative effects of T. ornata on some coral species are subordinate to those of fish predation and are, therefore, likely to manifest only on reefs severely depleted of predators. In contrast, space dominance by T. ornata may decrease the growth of other coral species regardless of predation intensity. In general, this study shows that susceptibility to predation may determine the severity of the effects of canopy-forming macroalgae on coral growth.

  10. A Stable Thoracic Hox Code and Epimorphosis Characterize Posterior Regeneration in Capitella teleta

    PubMed Central

    de Jong, Danielle M.; Seaver, Elaine C.

    2016-01-01

    Regeneration, the ability to replace lost tissues and body parts following traumatic injury, occurs widely throughout the animal tree of life. Regeneration occurs either by remodeling of pre-existing tissues, through addition of new cells by cell division, or a combination of both. We describe a staging system for posterior regeneration in the annelid, Capitella teleta, and use the C. teleta Hox gene code as markers of regional identity for regenerating tissue along the anterior-posterior axis. Following amputation of different posterior regions of the animal, a blastema forms and by two days, proliferating cells are detected by EdU incorporation, demonstrating that epimorphosis occurs during posterior regeneration of C. teleta. Neurites rapidly extend into the blastema, and gradually become organized into discrete nerves before new ganglia appear approximately seven days after amputation. In situ hybridization shows that seven of the ten Hox genes examined are expressed in the blastema, suggesting roles in patterning the newly forming tissue, although neither spatial nor temporal co-linearity was detected. We hypothesized that following amputation, Hox gene expression in pre-existing segments would be re-organized to scale, and the remaining fragment would express the complete suite of Hox genes. Surprisingly, most Hox genes display stable expression patterns in the ganglia of pre-existing tissue following amputation at multiple axial positions, indicating general stability of segmental identity. However, the three Hox genes, CapI-lox4, CapI-lox2 and CapI-Post2, each shift its anterior expression boundary by one segment, and each shift includes a subset of cells in the ganglia. This expression shift depends upon the axial position of the amputation. In C. teleta, thoracic segments exhibit stable positional identity with limited morphallaxis, in contrast with the extensive body remodeling that occurs during regeneration of some other annelids, planarians and acoel

  11. A Stable Thoracic Hox Code and Epimorphosis Characterize Posterior Regeneration in Capitella teleta.

    PubMed

    de Jong, Danielle M; Seaver, Elaine C

    2016-01-01

    Regeneration, the ability to replace lost tissues and body parts following traumatic injury, occurs widely throughout the animal tree of life. Regeneration occurs either by remodeling of pre-existing tissues, through addition of new cells by cell division, or a combination of both. We describe a staging system for posterior regeneration in the annelid, Capitella teleta, and use the C. teleta Hox gene code as markers of regional identity for regenerating tissue along the anterior-posterior axis. Following amputation of different posterior regions of the animal, a blastema forms and by two days, proliferating cells are detected by EdU incorporation, demonstrating that epimorphosis occurs during posterior regeneration of C. teleta. Neurites rapidly extend into the blastema, and gradually become organized into discrete nerves before new ganglia appear approximately seven days after amputation. In situ hybridization shows that seven of the ten Hox genes examined are expressed in the blastema, suggesting roles in patterning the newly forming tissue, although neither spatial nor temporal co-linearity was detected. We hypothesized that following amputation, Hox gene expression in pre-existing segments would be re-organized to scale, and the remaining fragment would express the complete suite of Hox genes. Surprisingly, most Hox genes display stable expression patterns in the ganglia of pre-existing tissue following amputation at multiple axial positions, indicating general stability of segmental identity. However, the three Hox genes, CapI-lox4, CapI-lox2 and CapI-Post2, each shift its anterior expression boundary by one segment, and each shift includes a subset of cells in the ganglia. This expression shift depends upon the axial position of the amputation. In C. teleta, thoracic segments exhibit stable positional identity with limited morphallaxis, in contrast with the extensive body remodeling that occurs during regeneration of some other annelids, planarians and acoel

  12. A Stable Thoracic Hox Code and Epimorphosis Characterize Posterior Regeneration in Capitella teleta.

    PubMed

    de Jong, Danielle M; Seaver, Elaine C

    2016-01-01

    Regeneration, the ability to replace lost tissues and body parts following traumatic injury, occurs widely throughout the animal tree of life. Regeneration occurs either by remodeling of pre-existing tissues, through addition of new cells by cell division, or a combination of both. We describe a staging system for posterior regeneration in the annelid, Capitella teleta, and use the C. teleta Hox gene code as markers of regional identity for regenerating tissue along the anterior-posterior axis. Following amputation of different posterior regions of the animal, a blastema forms and by two days, proliferating cells are detected by EdU incorporation, demonstrating that epimorphosis occurs during posterior regeneration of C. teleta. Neurites rapidly extend into the blastema, and gradually become organized into discrete nerves before new ganglia appear approximately seven days after amputation. In situ hybridization shows that seven of the ten Hox genes examined are expressed in the blastema, suggesting roles in patterning the newly forming tissue, although neither spatial nor temporal co-linearity was detected. We hypothesized that following amputation, Hox gene expression in pre-existing segments would be re-organized to scale, and the remaining fragment would express the complete suite of Hox genes. Surprisingly, most Hox genes display stable expression patterns in the ganglia of pre-existing tissue following amputation at multiple axial positions, indicating general stability of segmental identity. However, the three Hox genes, CapI-lox4, CapI-lox2 and CapI-Post2, each shift its anterior expression boundary by one segment, and each shift includes a subset of cells in the ganglia. This expression shift depends upon the axial position of the amputation. In C. teleta, thoracic segments exhibit stable positional identity with limited morphallaxis, in contrast with the extensive body remodeling that occurs during regeneration of some other annelids, planarians and acoel

  13. The Contemporary State of Development of Free-living Nematodes of the Northwestern Black Sea

    NASA Astrophysics Data System (ADS)

    Kulakova, I.

    2007-05-01

    -50% of density of colonization. Besides Sabatieria abissalis on the Romanian shelf transects (35% of density), Sabatieria pulchra occurs from 12 to 35%. Sabatieria pulchra dominates on the Ukrainian shelf. Literature data have shown that the ecological niches of these close related species diverge spatially. Sabatieria abissalis prefer to inhabit the upper layers of sediment with adequate oxygen, while Sabatieria pulchra inhabits sediment layers with low oxygen content in silt sediments. At deep water stations where the anthropogenic load is less, k-dominance curves for species biomass and abundance (ABC curves) showing stable unpolluted nematode communities. The amount of dominating species increased with Sabatieria abissalis prevailing. The results of this study illustrate the part played by nematodes in the formation of quantitative parameters of meiobenthos in this area. This kind of meiobenthos is the most suitable for practical biological monitoring of the Black Sea. The increase or decrease in nematode species diversity gives evidence of the state of meiobenthos communities.

  14. Free-Nematodes in the NW Black Sea meiobenthos - diversity, abundance, distribution and importance as indicator of hypoxic waters

    NASA Astrophysics Data System (ADS)

    Muresan, M.; Gomoiu, M.-T.

    2012-04-01

    The aim of this study performed within EU FP7 Hypox Project was to get deeper knowledge about species of nematodes that could be indicators for stressful biotic conditions as low oxygen concentration due to phenomena of seasonal hypoxia. The Nematodes come from meiobenthos sampling (using a multi corer with 4 tubes, Mark II type, lowered into the sea from R/V "Mare Nigrum" board) performed in May and September 2010 and April 2011 along four transects crossing the Romanian continental shelf from where 87 meiobenthos samples were collected. In the studied area 96 species of nematodes were found. The authors analyzed the nematodes populations' distribution on four profiles: Sf. Gheorghe, Portita, Constanta and Mangalia. The qualitative and quantitative structure of nematodes populations was compared. 41 species were found on Mangalia profile, 47 species on Portita profile, 48 species on Constanta profile and 85 species on Sf. Gheorghe profile. The greatest densities were found on Constanta profile with an average of 369.607indvs/m-2. The most frequent and abundant species were: Sabatieria pulchra, Sabatieria abyssalis, Terschellingia longicaudata, Viscosia cobbi, Axonolaimus ponticus. The species assemblages were assessed for depth gradient distribution, 7 depth intervals being set from 20 to 210 m. The greatest diversity was noted in 61-100 m depth interval, while the lowest between 0-20 m. On the contrary, in terms of density of individuals (indvs/m-2), highest densities were obtained in shallow waters between 21-30 m. As far as the depth increases, the species assemblages change, becoming more favorable to species like Halalaimus ponticus, Metachromadora macrouthera, Halanonchus bullatus, Linhomoneidae species. However, on the first place still remained Sabatieria abyssalis. The vertical distribution of nematodes in sediments was analyzed for the surface layer 0-5 cm and sub-surface layer 5-10 cm, the dominant species in both layers being: Sabatieria pulchra, S

  15. Characterizing Variation of Isotopic Markers in Northern Alaskan Caribou Forages

    NASA Astrophysics Data System (ADS)

    VanSomeren, L.; Barboza, P. S.; Gustine, D. D.; Parrett, L. S.; Stricker, C. A.

    2013-12-01

    Isotopic markers in feces and tissues are a potential tool for monitoring the importance of feeding areas for migratory herbivores such as caribou (Rangifer tarandus). Many of these techniques are currently limited by gaps in our knowledge of how these isotopic signatures vary over the landscape. We collected seven species of preferred caribou forages along a latitudinal gradient in the summer ranges of the Central Arctic (9 sites) and Teshekpuk Lake (4 sites) caribou herds during 2011 and 2012. We analyzed forages at peak protein content and at the end of the season to characterize temporal, species-specific, and spatial variation in isotopic markers. The availability of C and N was measured by digestion in vitro. Isotopic signatures of digested samples were used to calculate fractionation that would bias the isotopic signature of feces. The range of values for isotopes (all values ‰) of nitrogen (δ15N -9.5 - +4.3), and sulfur (δ34S -3.6 - +15.5) were greater than those for carbon (δ13C -30.5 - -24.9). Small declines in forage δ13C with latitude (Carex aquatilis, Eriophorum vaginatum, Salix pulchra, and S. richardsonii [all P < 0.01]), season (all species except C. bigelowii [all P ≤ 0.01]), and season x year (S. richardsonii; P = 0.01) were probably associated with changes in water availability. Fractionation of δ13C in early season forages was 0.1 × 1.0 and positively related to C availability (58% × 15%; P < 0.01) with the greatest fractionation for the highly digestible forb Pedicularis langsdorfii (1.43 × 0.44; P < 0.01). Sedges (Carex and Eriophorum) were significantly higher in δ15N than Salix spp. and other dicots (2.0 × 1.1 vs. -2.9 × 2.2; P < 0.01). For Salix spp., δ15N was consistent over the season and between years. Fractionation of δ15N in early season forages was 0.2 × 1.8 and not related to N availability (60% × 17%). For S. pulchra, δ34S may indicate usage of coastal habitats over foothills because δ34S was higher on the

  16. High resolution paleoceanography of the Guaymas Basin, Gulf of California, during the past 15 000 years

    USGS Publications Warehouse

    Barron, J.A.; Bukry, D.; Bischoff, J.L.

    2004-01-01

    Deep Sea Drilling Project Site 480 (27??54.10???N, 111??39.34???W; 655 m water depth) contains a high resolution record of paleoceanographic change of the past 15 000 years for the Guaymas Basin, a region of very high diatom productivity within the central Gulf of California. Analyses of diatoms and silicoflagellates were completed on samples spaced every 40-50 yr, whereas ICP-AES geochemical analyses were completed on alternate samples (sample spacing 80-100 yr). The B??lling-Aller??d interval (14.6-12.9 ka) (note, ka refers to 1000 calendar years BP throughout this report) is characterized by an increase in biogenic silica and a decline in calcium carbonate relative to surrounding intervals, suggesting conditions somewhat similar to those of today. The Younger Dryas event (12.9-11.6 ka) is marked by a major drop in biogenic silica and an increase in calcium carbonate. Increasing relative percentage contributions of Azpeitia nodulifera and Dictyocha perlaevis (a tropical diatom and silicoflagellate, respectively) and reduced numbers of the silicoflagellate Octactis pulchra are supportive of reduced upwelling of nutrient-rich waters. Between 10.6 and 10.0 ka, calcium carbonate and A. nodulifera abruptly decline at DSDP 480, while Roperia tesselata, a diatom indicative of winter upwelling in the modern-day Gulf, increases sharply in numbers. A nearly coincident increase in the silicoflagellate Dictyocha stapedia suggests that waters above DSDP 480 were more similar to the cooler and slightly more saline waters of the northern Gulf during much of the early and middle parts of the Holocene (???10 to 3.2 ka). At about 6.2 ka a stepwise increase in biogenic silica and the reappearance of the tropical diatom A. nodulifera marks a major change in oceanographic conditions in the Gulf. A winter shift to more northwesterly winds may have occurred at this time along with the onset of periodic northward excursions (El Nin??o-driven?) of the North Equatorial Countercurrent

  17. Conformational landscape of an amyloid intra-cellular domain and Landau-Ginzburg-Wilson paradigm in protein dynamics

    NASA Astrophysics Data System (ADS)

    Dai, Jin; Niemi, Antti J.; He, Jianfeng

    2016-07-01

    The Landau-Ginzburg-Wilson paradigm is proposed as a framework, to investigate the conformational landscape of intrinsically unstructured proteins. A universal Cα-trace Landau free energy is deduced from general symmetry considerations, with the ensuing all-atom structure modeled using publicly available reconstruction programs Pulchra and Scwrl. As an example, the conformational stability of an amyloid precursor protein intra-cellular domain (AICD) is inspected; the reference conformation is the crystallographic structure with code 3DXC in Protein Data Bank (PDB) that describes a heterodimer of AICD and a nuclear multi-domain adaptor protein Fe65. Those conformations of AICD that correspond to local or near-local minima of the Landau free energy are identified. For this, the response of the original 3DXC conformation to variations in the ambient temperature is investigated, using the Glauber algorithm. The conclusion is that in isolation the AICD conformation in 3DXC must be unstable. A family of degenerate conformations that minimise the Landau free energy is identified, and it is proposed that the native state of an isolated AICD is a superposition of these conformations. The results are fully in line with the presumed intrinsically unstructured character of isolated AICD and should provide a basis for a systematic analysis of AICD structure in future NMR experiments.

  18. Conformational landscape of an amyloid intra-cellular domain and Landau-Ginzburg-Wilson paradigm in protein dynamics.

    PubMed

    Dai, Jin; Niemi, Antti J; He, Jianfeng

    2016-07-28

    The Landau-Ginzburg-Wilson paradigm is proposed as a framework, to investigate the conformational landscape of intrinsically unstructured proteins. A universal Cα-trace Landau free energy is deduced from general symmetry considerations, with the ensuing all-atom structure modeled using publicly available reconstruction programs Pulchra and Scwrl. As an example, the conformational stability of an amyloid precursor protein intra-cellular domain (AICD) is inspected; the reference conformation is the crystallographic structure with code 3DXC in Protein Data Bank (PDB) that describes a heterodimer of AICD and a nuclear multi-domain adaptor protein Fe65. Those conformations of AICD that correspond to local or near-local minima of the Landau free energy are identified. For this, the response of the original 3DXC conformation to variations in the ambient temperature is investigated, using the Glauber algorithm. The conclusion is that in isolation the AICD conformation in 3DXC must be unstable. A family of degenerate conformations that minimise the Landau free energy is identified, and it is proposed that the native state of an isolated AICD is a superposition of these conformations. The results are fully in line with the presumed intrinsically unstructured character of isolated AICD and should provide a basis for a systematic analysis of AICD structure in future NMR experiments.

  19. A new species of Moennigia (Trichostrongylina: Molineidae) a parasite of Chaetophractus spp. (Xenarthra: Dasypodidae) from Argentina.

    PubMed

    Ezquiaga, María C; Navone, Graciela T

    2014-08-01

    Moennigia celinae n. sp. collected from the small intestine of Chaetophractus vellerosus and Chaetophractus villosus (Xenarthra, Dasypodidae) from Argentina is herein described. This new species belongs to the genus Moennigia because it possesses a short uterus with few eggs, atrophied distal branch of the ovejector, vulva near the anus, and a conical tail. The new species has a synlophe with 17 symmetrical ridges and slight ventro-dorsal orientation. The spicule length:body length ratio is similar to that of the other species parasitic of Dasypodidae; however, Moennigia celinae n. sp. differs from Moennigia pintoi and Moennigia lutzi because the latter lack a gubernaculum, and from Moennigia complexus, Moennigia moennigi, Moennigia filamentosus, Moennigia intrusa, Moennigia littlei, Moennigia pulchra and Moennigia dessetae by the latter having very complex spicules with 2 or 3 points at the distal extremity. Moreover, Moennigia celinae n. sp. differs from Moennigia virilis by the length and shape of its spicules. Moennigia celinae n. sp. can be distinguished from Moennigia travassosi by the shape of the dorsal ray of the caudal bursa. Moennigia celinae n. sp. resembles Moennigia pseudopulchra but the gubernaculum of the latter is V-shaped. This is the second report of a species of Moennigia in Argentina and the first for the genus Chaetophractus. PMID:24552210

  20. Revision of the genus Turris Batsch, 1789 (Gastropoda: Conoidea: Turridae) with the description of six new species

    PubMed Central

    Kilburn, Richard N.; Fedosov, Alexander E.; Olivera, Baldomero M.

    2012-01-01

    The taxonomy of the genus Turris Batsch, 1789, type genus of the family Turridae, widespread in shallow-water habitats of tropic Indo-Pacific, is revised. A total of 31 species of Turris, are here recognized as valid. New species described: Turris chaldaea, Turris clausifossata, Turris guidopoppei, Turris intercancellata, Turris kantori, T. kathiewayae. Homonym renamed: Turris bipartita nom. nov. for Pleurotoma variegata Kiener, 1839 (non Philippi, 1836). New synonymies: Turris ankaramanyensis Bozzetti, 2006 = Turris tanyspira Kilburn, 1975; Turris imperfecti, T. nobilis, T. pulchra and T. tornatum Röding, 1798, and Turris assyria Olivera, Seronay & Fedosov, 2010 = T. babylonia; Turris dollyi Olivera, 2000 = Pleurotoma crispa Lamarck, 1816; Turris totiphyllis Olivera, 2000 = Turris hidalgoi Vera-Peláez, Vega-Luz & Lozano-Francisco, 2000; Turris kilburni Vera-Peláez, Vega-Luz & Lozano-Francisco, 2000 = Turris pagasa Olivera, 2000; Turris (Annulaturris) munizi Vera-Peláez, Vega-Luz & Lozano-Francisco, 2000 = Gemmula lululimi Olivera, 2000. Revised status: Turris intricata Powell, 1964, Pleurotoma variegata Kiener, 1839 (non Philippi, 1836) and Pleurotoma yeddoensis Jousseaume, 1883, are regarded as full species (not subspecies of Turris crispa). Neotype designated: For Pleurotoma garnonsii Reeve, 1843, to distinguish it from Turris garnonsii of recent authors, type locality emended to Zanzibar. New combination: Turris orthopleura Kilburn, 1983, is transferred to genus Makiyamaia, family Clavatulidae. PMID:23847408

  1. γ-Alkylidene-γ-lactones and isobutylpyrrol-2(5H)-ones analogues to rubrolides as inhibitors of biofilm formation by gram-positive and gram-negative bacteria.

    PubMed

    Pereira, Ulisses A; Barbosa, Luiz C A; Maltha, Célia R A; Demuner, Antônio J; Masood, Mohammed A; Pimenta, Andréa L

    2014-02-15

    Several molecules have been discovered that interfere with formation of bacterial biofilms, opening a new strategy for the development of more efficient treatments in case of antibiotic resistant bacteria. Amongst the most active compounds are some natural brominated furanones from marine algae Delisea pulchra that have proven to be able to control pathogenic biofilms. We have recently reported that some rubrolide analogues are able to inhibit biofilm formation of Enterococcus faecalis. In the present Letter we describe results of the biological evaluation of a small library of 28 compounds including brominated furanones and the corresponding lactams against biofilm formation of Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis and Streptococcus mutans. Our results showed that in general these compounds were more active against biofilms of S. epidermidis and P. aeruginosa, with little or no inhibition of planktonic bacterial growth. In some cases they were able to prevent biofilm formation of P. aeruginosa at concentrations as low as 0.6 μg/mL (1.3 μM, compound 3d) and 0.7 μg/mL (1.3 μM, 3f). Results also indicate that, in general, lactams are more active against biofilms than their precursors, thus designating this class of molecules as good candidates for the development of a new generation of antimicrobial drugs targeted to biofilm inhibition.

  2. The Contribution of Moss to Plot-Based Spectral Signals in Moist Acidic Low Arctic Tundra

    NASA Astrophysics Data System (ADS)

    May, J. L.; Beamish, A. L.

    2015-12-01

    To determine the contribution of moss to peak season normalized difference index (NDVI) field measurement of intact vegetation communities were compared to communities with individual species and litter successively removed until only the moss layer remained. Spectral measurements (n=3) were collected using a field radiometer in five upland and five lowland plots in a moist acidic tundra ecosystem at the Imnaviat Creek Watershed, North Slope Alaska. After spectral measurements were taken individual species were removed in the same order in each plot by clipping them at the moss layer. As individual species were removed NDVI values decreased. Decreases were greatest when dwarf shrub species Salix richardsonii sb. pulchra and Betula nana were removed. Notable increases in NDVI were observed once standing litter was removed. The NDVI values of the moss layer were comparable to intact vegetation communities depending on the bryophyte species composition. This suggests that the NDVI signal of moss is largely masked by vascular species but represents a significant factor missing from overall, large-scale NDVI signals. The results of this study corroborate recent data that points to the mismatch between ground based NDVI and aerial and satellite derived NDVI. This preliminary case study provides a strong basis for better characterization of the contribution of moss to NDVI for improved correction of air and space borne imagery.

  3. Ontogeny of behavioural adaptations in beach crustaceans: some temporal considerations for integrated coastal zone management and conservation

    NASA Astrophysics Data System (ADS)

    Naylor, E.; Kennedy, F.

    2003-10-01

    So-called "typical" behavioural responses of coastal animals to particular stimuli have previously been shown often to vary cyclically in phase with diel or tidal cycles in the environment. Less well-studied are differences in the behaviour of adults and juveniles of the same species at the same time of day or tidal state, or in response to the same stimulus. Experimental studies of such differences in behaviour are reviewed and compared for three species of beach crustaceans, namely, the crab Carcinus maenas, the isopod Eurydice pulchra and the amphipod Orchestoidea tuberculata. Juvenile, but not adult, Carcinus will entrain circatidal rhythmicity after exposure to artificial tidal cycles of immersion/emersion; juvenile, but not adult, Eurydice express pronounced free-running circatidal swimming rhythms at neap tides as well as at springs; and, in Orchestoidea, juveniles and adults express patterns of daily locomotor activity that are complementary, both on the shore and in the laboratory. These ontogenetic differences are discussed in relation to distributional and behavioural differences between adults and juveniles in each species, drawing attention to their adaptive significance and wider implications for coastal management and conservation.

  4. Revision, cladistic analysis and biogeography of Typhochlaena C. L. Koch, 1850, Pachistopelma Pocock, 1901 and Iridopelma Pocock, 1901 (Araneae, Theraphosidae, Aviculariinae)

    PubMed Central

    Bertani, Rogério

    2012-01-01

    Abstract Three aviculariine genera endemic to Brazil are revised. Typhochlaena C. L. Koch, 1850 is resurrected, including five species; Pachistopelma Pocock, 1901 includes two species; and Iridopelma Pocock, 1901, six species. Nine species are newly described: Typhochlaena amma sp. n., Typhochlaena costae sp. n., Typhochlaena curumim sp. n., Typhochlaena paschoali sp. n., Pachistopelma bromelicola sp. n., Iridopelma katiae sp. n., Iridopelma marcoi sp. n., Iridopelma oliveirai sp. n. and Iridopelma vanini sp. n. Three new synonymies are established: Avicularia pulchra Mello-Leitão, 1933 and Avicularia recifiensis Struchen & Brändle, 1996 are junior synonyms of Pachistopelma rufonigrum Pocock, 1901 syn. n., and Avicularia palmicola Mello-Leitão, 1945 is a junior synonym of Iridopelma hirsutum Pocock, 1901 syn. n. Pachistopelma concolor Caporiacco, 1947 is transferred to Tapinauchenius Ausserer, 1871, making the new combination Tapinauchenius concolor (Caporiacco, 1947) comb. n. Lectotypes are newly designed for Pachistopelma rufonigrum Pocock, 1901 , Iridopelma hirsutum Pocock, 1901 and Pachistopelma concolor Caporiacco, 1947. Cladistic analyses using both equal and implied weights were carried out with a matrix comprising 62 characters and 38 terminal taxa. The chosen cladogram found with X-Pee-Wee and concavity 6 suggests they are monophyletic. All species are keyed and mapped and information on species habitat and area cladograms are presented. Discussion on biogeography and conservation is provided. PMID:23166476

  5. Revision, cladistic analysis and biogeography of Typhochlaena C. L. Koch, 1850, Pachistopelma Pocock, 1901 and Iridopelma Pocock, 1901 (Araneae, Theraphosidae, Aviculariinae).

    PubMed

    Bertani, Rogério

    2012-01-01

    Three aviculariine genera endemic to Brazil are revised. Typhochlaena C. L. Koch, 1850 is resurrected, including five species; Pachistopelma Pocock, 1901 includes two species; and Iridopelma Pocock, 1901, six species. Nine species are newly described: Typhochlaena ammasp. n., Typhochlaena costaesp. n., Typhochlaena curumimsp. n., Typhochlaena paschoalisp. n., Pachistopelma bromelicolasp. n., Iridopelma katiaesp. n., Iridopelma marcoisp. n., Iridopelma oliveiraisp. n. and Iridopelma vaninisp. n. Three new synonymies are established: Avicularia pulchra Mello-Leitão, 1933 and Avicularia recifiensis Struchen & Brändle, 1996 are junior synonyms of Pachistopelma rufonigrum Pocock, 1901 syn. n., and Avicularia palmicola Mello-Leitão, 1945 is a junior synonym of Iridopelma hirsutum Pocock, 1901 syn. n.Pachistopelma concolor Caporiacco, 1947 is transferred to Tapinauchenius Ausserer, 1871, making the new combination Tapinauchenius concolor (Caporiacco, 1947)comb. n. Lectotypes are newly designed for Pachistopelma rufonigrum Pocock, 1901 , Iridopelma hirsutum Pocock, 1901 and Pachistopelma concolor Caporiacco, 1947. Cladistic analyses using both equal and implied weights were carried out with a matrix comprising 62 characters and 38 terminal taxa. The chosen cladogram found with X-Pee-Wee and concavity 6 suggests they are monophyletic. All species are keyed and mapped and information on species habitat and area cladograms are presented. Discussion on biogeography and conservation is provided. PMID:23166476

  6. Hybridization of two megacephalic map turtles (testudines: emydidae: Graptemys) in the Choctawhatchee River drainage of Alabama and Florida

    USGS Publications Warehouse

    Godwin, James; Lovich, Jeffrey E.; Ennen, Joshua R.; Kreiser, Brian R.; Folt, Brian; Lechowicz, Chris

    2014-01-01

    Map turtles of the genus Graptemys are highly aquatic and rarely undergo terrestrial movements, and limited dispersal among drainages has been hypothesized to drive drainage-specific endemism and high species richness of this group in the southeastern United States. Until recently, two members of the megacephalic “pulchra clade,” Graptemys barbouri andGraptemys ernsti, were presumed to be allopatric with a gap in both species' ranges in the Choctawhatchee River drainage. In this paper, we analyzed variation in morphology (head and shell patterns) and genetics (mitochondrial DNA and microsatellite loci) from G. barbouri, G. ernsti, and Graptemys sp. collected from the Choctawhatchee River drainage, and we document the syntopic occurrence of those species and back-crossed individuals of mixed ancestry in the Choctawhatchee River drainage. Our results provide a first counter-example to the pattern of drainage-specific endemism in megacephalic Graptemys. Geologic events associated with Pliocene and Pleistocene sea level fluctuations and the existence of paleo-river systems appear to have allowed the invasion of the Choctawhatchee system by these species, and the subsequent introgression likely predates any potential human-mediated introduction.

  7. Twelve new species and fifty-three new provincial distribution records of Aleocharinae rove beetles of Saskatchewan, Canada (Coleoptera, Staphylinidae)

    PubMed Central

    Klimaszewski, Jan; Larson, David J.; Labrecque, Myriam; Bourdon, Caroline

    2016-01-01

    Abstract One hundred twenty species of aleocharine beetles (Staphylinidae) are recognized in the province of Saskatchewan. Sixty-five new provincial records, including twelve new species and one new North American record, are presented. Oligota inflata (Mannerheim), a Palearctic species, is newly recorded for North America. The following twelve species are described as new to science: Acrotona pseudopygmaea Klimaszewski & Larson, sp. n., Agaricomorpha pulchra Klimaszewski & Larson, sp. n. (new genus record for Canadian fauna), Aleochara elisabethae Klimaszewski & Larson, sp. n., Atheta (Dimetrota) larsonae Klimaszewski & Larson, sp. n., Atheta (Microdota) pseudopittionii Klimaszewski & Larson, sp. n., Atheta (Microdota) spermathecorum Klimaszewski & Larson, sp. n., Atheta (sensu lato) richardsoni Klimaszewski & Larson, sp. n., Brachyusa saskatchewanae Klimaszewski & Larson, sp. n., Dochmonota langori Klimaszewski & Larson, sp. n., Dochmonota simulans Klimaszewski & Larson, sp. n., Dochmonota websteri Klimaszewski & Larson, sp. n., and Oxypoda domestica Klimaszewski & Larson, sp. n. Colour images of habitus and black and white images of the median lobe of the aedeagus, spermatheca, and tergite and sternite VIII are presented for all new species, Oligota inflata Mannerheim and Dochmonota rudiventris (Eppelsheim). A new synonymy is established: Tetralina filitarsus Casey, syn. n. = Tetralina helenae Casey, now placed in the genus Brachyusa Mulsant & Rey. PMID:27587977

  8. Temperature-dependent acute toxicity of methomyl pesticide on larvae of 3 Asian amphibian species.

    PubMed

    Lau, Edward Tak Chuen; Karraker, Nancy Elizabeth; Leung, Kenneth Mei Yee

    2015-10-01

    Relative to other animal taxa, ecotoxicological studies on amphibians are scarce, even though amphibians are experiencing global declines and pollution has been identified as an important threat. Agricultural lands provide important habitats for many amphibians, but often these lands are contaminated with pesticides. The authors determined the acute toxicity, in terms of 96-h median lethal concentrations, of the carbamate pesticide methomyl on larvae of 3 Asian amphibian species, the Asian common toad (Duttaphrynus melanostictus), the brown tree frog (Polypedates megacephalus), and the marbled pygmy frog (Microhyla pulchra), at 5 different temperatures (15 °C, 20 °C, 25 °C, 30 °C, and 35 °C) to examine the relationships between temperature and toxicity. Significant interspecific variation in methomyl sensitivity and 2 distinct patterns of temperature-dependent toxicity were found. Because high proportions of malformation among the surviving tadpoles were observed, a further test was carried out on the tree frog to determine effect concentrations using malformation as the endpoint. Concentrations as low as 1.4% of the corresponding 96-h median lethal concentrations at 25 °C were sufficient to cause malformation in 50% of the test population. As the toxicity of pesticides may be significantly amplified at higher temperatures, temperature effects should not be overlooked in ecotoxicological studies and derivation of safety limits in environmental risk assessment and management.

  9. Morphological variability in tree root architecture indirectly affects coexistence among competitors in the understory.

    PubMed

    Aschehoug, Erik T; Callaway, Ragan M

    2014-07-01

    Interactions between plants can have strong effects on community structure and function. Variability in the morphological, developmental, physiological, and biochemical traits of plants can influence the outcome of plant interactions and thus have important ecological consequences. However, the ecological ramifications of trait variability in plants are poorly understood and have rarely been tested in the field. We experimentally tested the effects of morphological variation in root architecture of Quercus douglasii trees in the field on interactions between understory plants and community composition. Our results indicate that variability among Q. douglasii tree root systems initiates a striking reversal in the competitive effects of dominant understory grass species on a less common species. Trees with a deep-rooted morphology facilitated exotic annual grasses and these annual grasses, in turn, competitively excluded the native perennial bunchgrass, Stipapulchra. In contrast, Q. douglasii trees with shallow-rooted morphologies directly suppressed the growth of exotic annual grasses and indirectly released S. pulchra individuals from competition with these annual grasses. Morphological variation in the root architecture of Q. douglasii created substantial conditionality in the outcomes of competition among species which enhanced the potential for indirect interactions to sustain coexistence and increase community diversity.

  10. Systematics and biology of Xylocopa subgenus Schonnherria (Hymenoptera, Apidae) in Argentina

    PubMed Central

    Lucia, Mariano; Gonzalez, Victor H.; Abrahamovich, Alberto H.

    2015-01-01

    Abstract Biological information on the species of the large carpenter bee Xylocopa subgenus Schonnherria occurring in Argentina is revised. Based on the appraisal of museum specimens, the study of type material, and field surveys conducted across 15 provinces between 2007 and 2011, the following seven species are recognized for the country: Xylocopa bambusae Schrottky, Xylocopa chrysopoda Schrottky, Xylocopa macrops Lepeletier de Saint Fargeau, Xylocopa simillima Smith Xylocopa splendidula Lepeletier de Saint Fargeau, Xylocopa pulchra Smith, and Xylocopa viridis Smith. Previous literature records of Xylocopa dimidiata Latreille, Xylocopa subcyanea Pérez, and Xylocopa varians Smith for the province of Misiones appear to have been misidentified specimens, although the presence of these species in Argentina cannot be entirely ruled out given the proximity of this province to Brazil and Paraguay where they occur; Xylocopa boops Maidl was described from a male specimen with unusually enlarged eyes and is newly synonymized under Xylocopa macrops. Males and females of all species are diagnosed, described, and figured, including details of the male genitalia. Taxonomic comments, data on the geographical distribution and nesting substrates, and identification keys to all Argentinean species of Schonnherria are provided. The nesting biologies of Xylocopa splendidula and Xylocopa viridis are documented. PMID:26798288

  11. Synthesis, quorum sensing inhibition and docking studies of 1,5-dihydropyrrol-2-ones.

    PubMed

    Goh, Wai-Kean; Gardner, Christopher R; Chandra Sekhar, Kondapalli V G; Biswas, Nripendra N; Nizalapur, Shashidhar; Rice, Scott A; Willcox, Mark; Black, David StC; Kumar, Naresh

    2015-12-01

    Gram-negative bacteria such as Pseudomonas aeruginosa and Escherichia coli use N-acylated l-homoserine lactones (AHLs) as autoinducers (AIs) for quorum sensing (QS), a chief regulatory and cell-to-cell communication system. QS is responsible for social adaptation, virulence factor production, biofilm production and antibiotic resistance in bacteria. Fimbrolides, a class of halogenated furanones isolated from the red marine alga Delisea pulchra, have been shown to exhibit promising QS inhibitory activity against various Gram-negative and Gram-positive bacterial strains. In this work, various lactam analogues of fimbrolides viz., 1,5-dihydropyrrol-2-ones, were designed and synthesized via an efficient lactamization protocol. All the synthesized analogues were tested for QS inhibition against the E. coli AHL-monitor strain JB357 gfp (ASV). Compound 17a emerged as the most potent compound, followed by 9c, with AIC40 values (the ratio of synthetic inhibitor to natural AHL signaling molecule that is required to lower GFP expression to 40%) of 1.95 and 19.00, respectively. Finally, the potential binding interactions between the synthesized molecules and the LasR QS receptor were studied by molecular docking. Our results indicate that 1,5-dihydropyrrol-2-ones have the ability to serve as potential leads for the further development of novel QS inhibitors as antimicrobial therapeutics. PMID:26547407

  12. Characterization of fatty acid composition in healthy and bleached corals from Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Bachok, Zainudin; Mfilinge, Prosper; Tsuchiya, Makoto

    2006-11-01

    Under bleaching conditions, corals lose their symbiotic zooxanthellae, and thus, the ability to synthesize fatty acids (FAs) from photosynthetically derived carbon. This study investigated the lipid content and FA composition in healthy and bleached corals from the Odo reef flat in Okinawa, southern Japan, following a bleaching event. It was hypothesized that the FA composition and abundance would change as algae are lost or die, and possibly microbial abundance would increase in corals as a consequence of bleaching. The lipid content and FA composition of three healthy coral species ( Pavona frondifera, Acropora pulchra, and Goniastrea aspera) and of partially bleached and completely bleached colonies of P. frondifera were examined. The FA composition did not differ among healthy corals, but differed significantly among healthy, partially bleached, and completely bleached specimens of P. frondifera. Completely bleached corals contained significantly lower lipid and total FA content, as well as lower relative amounts of polyunsaturated FAs and higher relative amounts of saturated FAs, than healthy and partially bleached corals. Furthermore, there was a significantly higher relative concentration of monounsaturated FAs and odd-numbered branched FAs in completely bleached corals, indicating an increase in bacterial colonization in the bleached corals.

  13. Historical biogeography and speciation in the neotropical highlands: molecular phylogenetics of the jay genus Cyanolyca.

    PubMed

    Bonaccorso, Elisa

    2009-03-01

    Phylogenetic relationships were studied in the genus Cyanolyca, an assemblage of jays distributed from Mexico south to Bolivia. Given its fragmented distribution along the humid forests of the Neotropics, the genus Cyanolyca is a model group for exploring hypotheses on biogeography and speciation. Phylogenetic analyses were based on two mitochondrial and three nuclear loci; taxon sampling includes all species in the genus and most subspecies. Maximum parsimony, maximum likelihood, and Bayesian analyses produced trees that were congruent and highly robust at both terminal and deep nodes of the phylogeny. Cyanolyca comprises two major clades: one contains the Mesoamerican "dwarf" jays, and the other consists of two main groups--C. cucullata+C. pulchra and the "core" South American species. Prior hypotheses of relationships were explored statistically using Maximum Likelihood and Bayesian approaches. Dispersal-Vicariance analysis revealed the importance of the Northern Andes as a major center for biological diversification, and the effects of dispersal across the Panamanian Land Bridge in the composition of South American and Mesoamerican avifaunas. Phylogenetic patterns are highly congruent with an allopatric mode of speciation. Implications of these results are discussed in the context of the biogeography of Neotropical montane forests.

  14. Conformational landscape of an amyloid intra-cellular domain and Landau-Ginzburg-Wilson paradigm in protein dynamics.

    PubMed

    Dai, Jin; Niemi, Antti J; He, Jianfeng

    2016-07-28

    The Landau-Ginzburg-Wilson paradigm is proposed as a framework, to investigate the conformational landscape of intrinsically unstructured proteins. A universal Cα-trace Landau free energy is deduced from general symmetry considerations, with the ensuing all-atom structure modeled using publicly available reconstruction programs Pulchra and Scwrl. As an example, the conformational stability of an amyloid precursor protein intra-cellular domain (AICD) is inspected; the reference conformation is the crystallographic structure with code 3DXC in Protein Data Bank (PDB) that describes a heterodimer of AICD and a nuclear multi-domain adaptor protein Fe65. Those conformations of AICD that correspond to local or near-local minima of the Landau free energy are identified. For this, the response of the original 3DXC conformation to variations in the ambient temperature is investigated, using the Glauber algorithm. The conclusion is that in isolation the AICD conformation in 3DXC must be unstable. A family of degenerate conformations that minimise the Landau free energy is identified, and it is proposed that the native state of an isolated AICD is a superposition of these conformations. The results are fully in line with the presumed intrinsically unstructured character of isolated AICD and should provide a basis for a systematic analysis of AICD structure in future NMR experiments. PMID:27475398

  15. 2(5H)-Furanone, epigallocatechin gallate, and a citric-based disinfectant disturb quorum-sensing activity and reduce motility and biofilm formation of Campylobacter jejuni.

    PubMed

    Castillo, Sandra; Heredia, Norma; García, Santos

    2015-01-01

    Brominated furanone and epigallocatechin gallate (EGCG) are naturally occurring polyphenolic compounds that can be derived from sources such as Delisea pulchra algae and green tea, respectively. These compounds may have potential health benefits and antimicrobial properties. Biofilm formation and bacterial motility are virulence factors that seem to be involved in the autoinducer 2 (AI-2)-mediated quorum sensing (QS) response of Campylobacter. In this study, the anti-QS activities of 2(5H)-furanone, EGCG, and a citric-based disinfectant were tested against Campylobacter jejuni. The minimal bactericidal concentration (MBC) was determined by a microdilution method, and the AI-2 activity was measured by bioluminescence. For motility tests, subinhibitory concentrations of each compound were mixed with semisolid Muller Hinton agar. Biofilm formation was quantified in broth-containing microplates after staining with safranin. The MBC of tested compounds ranged from 0.3 to 310 μg/mL. Subinhibitory concentrations of all of the antimicrobial compounds significantly decreased (19 to 62 %) the bacterial motility and reduced biofilm formation. After treatment with EGCG, furanone, and the disinfectant, AI-2 activity was decreased by 60 to 99 % compared to control. In conclusion, 2(5H)-furanone, EGCG, and the disinfectant exert bactericidal effects against C. jejuni and disturb QS activity and reduce motility and biofilm formation. These compounds may be naturally occurring alternatives to control C. jejuni.

  16. Revision, cladistic analysis and biogeography of Typhochlaena C. L. Koch, 1850, Pachistopelma Pocock, 1901 and Iridopelma Pocock, 1901 (Araneae, Theraphosidae, Aviculariinae).

    PubMed

    Bertani, Rogério

    2012-01-01

    Three aviculariine genera endemic to Brazil are revised. Typhochlaena C. L. Koch, 1850 is resurrected, including five species; Pachistopelma Pocock, 1901 includes two species; and Iridopelma Pocock, 1901, six species. Nine species are newly described: Typhochlaena ammasp. n., Typhochlaena costaesp. n., Typhochlaena curumimsp. n., Typhochlaena paschoalisp. n., Pachistopelma bromelicolasp. n., Iridopelma katiaesp. n., Iridopelma marcoisp. n., Iridopelma oliveiraisp. n. and Iridopelma vaninisp. n. Three new synonymies are established: Avicularia pulchra Mello-Leitão, 1933 and Avicularia recifiensis Struchen & Brändle, 1996 are junior synonyms of Pachistopelma rufonigrum Pocock, 1901 syn. n., and Avicularia palmicola Mello-Leitão, 1945 is a junior synonym of Iridopelma hirsutum Pocock, 1901 syn. n.Pachistopelma concolor Caporiacco, 1947 is transferred to Tapinauchenius Ausserer, 1871, making the new combination Tapinauchenius concolor (Caporiacco, 1947)comb. n. Lectotypes are newly designed for Pachistopelma rufonigrum Pocock, 1901 , Iridopelma hirsutum Pocock, 1901 and Pachistopelma concolor Caporiacco, 1947. Cladistic analyses using both equal and implied weights were carried out with a matrix comprising 62 characters and 38 terminal taxa. The chosen cladogram found with X-Pee-Wee and concavity 6 suggests they are monophyletic. All species are keyed and mapped and information on species habitat and area cladograms are presented. Discussion on biogeography and conservation is provided.

  17. [The pollination of Krameria bahiana B.B. Simpson by bees in the Coastal Sand Plains of Bahia, Brazil].

    PubMed

    Gimenes, Miriam; Lobão, Cybelle da S

    2006-01-01

    The flowers of K. bahiana mainly produce oil as floral resource for their visitors. Oil collecting bees usually show morphological and behavioral adaptation for their collection. This study focused on the analysis of interactions between the flowers of K. bahiana and their visiting bees, aiming for the efficiency of the pollination, in an area of the Coastal Sand Plains of Bahia State, Brazil. From February/2001 to February/2002 and from May to October/2002 observations were accomplished about the phenology and morphology of the plants and the floral visitors' behavior. The flowers of the inflorescences are zigomorphic, small sized, pink and present a pair of petals modified in epithelial elaiophores, which are responsible for the production of oil. These flowers were visited especially by bees of the genus Centris: C. leprieuri Spinola, C. tarsata Smith, C. trigonoides Lepeletier and C. pulchra Moure, Oliveira & Viana. The bees collected only oil in the flowers, by scratching the elaiophores and then transferring it to scopa located on the tibia and basitarsus of the hind legs. During those actions, the bees often contact the reproductive structures of the flowers, resulting in pollination. C. leprieuri was the most frequent bee during this study, thus considered the effective pollinator. Megachile dentipes Vachal also visited the flowers of K. bahiana, collecting only pollen. However, these bees were considered sporadic pollinators because they were not frequent in the flowers of K. bahiana in the months of observation. PMID:17061790

  18. Assessing redox potential of a native tree from the Brazilian Atlantic Rainforest: a successful evaluation of oxidative stress associated to a new power generation source of an oil refinery.

    PubMed

    Esposito, Marisia Pannia; Pedroso, Andrea Nunes Vaz; Domingos, Marisa

    2016-04-15

    The antioxidant responses in saplings of Tibouchina pulchra (a native tree from the Brazilian Atlantic Rainforest) exposed around an oil refinery in the city of Cubatão (SE Brazil), varied during the exchange of its power generation source, from boilers fueled with oil to a thermoelectric fueled with natural gas. The redox potential changed in response to an interaction of air pollution and meteorological parameters, indicating that the pro-oxidant/antioxidant balance was not reached after the exchange of the power generation system. The gain in environmental quality in the region was not achieved as expected due the technological modernization, at least relative to oxidative stressors. These conclusions were based on results of analyses of enzymatic antioxidants: superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR); non-enzymatic antioxidants: reduced, oxidized and total ascorbic acid (AsA, DHA, totAA) and glutathione (GSH, GSSG, totG), their redox state (AsA/totAA and GSH/totG) and an indicator of lipid peroxidation (MDA). We also applied exploratory multivariate statistics in order to verify if the temporal sequence of changes in the plant redox capacity coincided with changes in the profile of air pollution, climatic conditions or with their interactions and if the environmental benefits that would supposedly be promoted by the mentioned exchange of power generation system were achieved in the region. PMID:26851758

  19. Species-level diversity of belowground structure in savanna woody plants

    NASA Astrophysics Data System (ADS)

    O'Donnell, F. C.; Caylor, K. K.; Bhattachan, A.; Dintwe, K.; D'Odorico, P.; Okin, G. S.

    2013-05-01

    Using compressed air, we excavated individual trees and shrubs and mapped their coarse root systems on a three-dimensional grid system up to 1.5 m depth. We excavated four woody savanna species at three sites spanning a climate gradient on the Kalahari Transect in southern Africa. Overall, species was more important than site in determining both large-scale and small-scale root system structure. The species excavated fell into two groups that coexisted across the climate gradient. Acacia mellifera and Terminalia sericea had straight roots in a laterally-extensive and relatively shallow system. Boscia albitrunca and Ochna pulchra had sinuous roots that were mostly concentrated beneath the canopy and were more prevalent in deep than near-surface soil layers, departing from the conventional model of decreasing root abundance with depth. The shallow-rooted species had small taproots, though it is unlikely that they reached the water table. Deep- and shallow-rootedness appear to correlate with other characteristics such as growth form (tree or shrub) and drought deciduousness. Acacia mellifera Boscia albitrunca

  20. Biogeochemical characterization of an undisturbed highly acidic, metal-rich bryophyte habitat, east-central Alaska, U.S.A.

    USGS Publications Warehouse

    Gough, L.P.; Eppinger, R.G.; Briggs, P.H.; Giles, S.

    2006-01-01

    We report on the geochemistry of soil and bryophyte-laden sediment and on the biogeochemistry of willows growing in an undisturbed volcanogenic massive sulfide deposit in the Alaska Range ecoregion of east-central Alaska. We also describe an unusual bryophyte assemblage found growing in the acidic metal-rich waters that drain the area. Ferricrete-cemented silty alluvial sediments within seeps and streams are covered with the liverwort Gymnocolea inflata whereas the mosses Polytrichum commune and P. juniperinum inhabit the area adjacent to the water and within the splash zone. Both the liverwort-encrusted sediment and Polytrichum thalli have high concentrations of major and trace metal cations (e.g., Al, As, Cu, Fe, Hg, La, Mn, Pb, and Zn). Soils in the area do not reflect the geochemical signature of the mineral deposit and we postulate they are influenced by the chemistry of eolian sediments derived from outside the deposit area. The willow, Salix pulchra, growing mostly within and adjacent to the larger streams, has much higher concentrations of Al, As, Cd, Cr, Fe, La, Pb, and Zn when compared to the same species collected in non-mineralized areas of Alaska. The Cd levels are especially high and are shown to exceed, by an order of magnitude, levels demonstrated to be toxic to ptarmigan in Colorado. Willow, growing in this naturally occurring metal-rich Red Mountain alteration zone, may adversely affect the health of browsing animals. ?? 2006 Regents of the University of Colorado.

  1. A Link No Longer Missing: New Evidence for the Cetotheriid Affinities of Caperea

    PubMed Central

    Marx, Felix G.; Fordyce, R. Ewan

    2016-01-01

    The origins of the enigmatic pygmy right whale Caperea marginata, the only living member of its subfamily (Neobalaeninae), are an outstanding mystery of cetacean evolution. Its strikingly disparate morphology sets Caperea apart from all other whales, and has turned it into a wildcard taxon that holds the key to understanding modern baleen whale diversity. Morphological cladistics generally ally this species with right whales, whereas molecular analyses consistently cluster it with rorquals and grey whales (Balaenopteroidea). A recent study potentially resolved this conflict by proposing that Caperea belongs with the otherwise extinct Cetotheriidae, but has been strongly criticised on morphological grounds. Evidence from the neobalaenine fossil record could potentially give direct insights into morphological transitions, but is currently limited to just a single species: the Late Miocene Miocaperea pulchra, from Peru. We show that Miocaperea has a highly unusual morphology of the auditory region, resulting from a–presumably feeding-related–strengthening of the articulation of the hyoid apparatus with the skull. This distinctive arrangement is otherwise only found in the extinct Cetotheriidae, which makes Miocaperea a “missing link” that demonstrates the origin of pygmy right whales from cetotheriids, and confirms the latter’s resurrection from the dead. PMID:27711216

  2. A new species of Moennigia (Trichostrongylina: Molineidae) a parasite of Chaetophractus spp. (Xenarthra: Dasypodidae) from Argentina.

    PubMed

    Ezquiaga, María C; Navone, Graciela T

    2014-08-01

    Moennigia celinae n. sp. collected from the small intestine of Chaetophractus vellerosus and Chaetophractus villosus (Xenarthra, Dasypodidae) from Argentina is herein described. This new species belongs to the genus Moennigia because it possesses a short uterus with few eggs, atrophied distal branch of the ovejector, vulva near the anus, and a conical tail. The new species has a synlophe with 17 symmetrical ridges and slight ventro-dorsal orientation. The spicule length:body length ratio is similar to that of the other species parasitic of Dasypodidae; however, Moennigia celinae n. sp. differs from Moennigia pintoi and Moennigia lutzi because the latter lack a gubernaculum, and from Moennigia complexus, Moennigia moennigi, Moennigia filamentosus, Moennigia intrusa, Moennigia littlei, Moennigia pulchra and Moennigia dessetae by the latter having very complex spicules with 2 or 3 points at the distal extremity. Moreover, Moennigia celinae n. sp. differs from Moennigia virilis by the length and shape of its spicules. Moennigia celinae n. sp. can be distinguished from Moennigia travassosi by the shape of the dorsal ray of the caudal bursa. Moennigia celinae n. sp. resembles Moennigia pseudopulchra but the gubernaculum of the latter is V-shaped. This is the second report of a species of Moennigia in Argentina and the first for the genus Chaetophractus.

  3. Assessing redox potential of a native tree from the Brazilian Atlantic Rainforest: a successful evaluation of oxidative stress associated to a new power generation source of an oil refinery.

    PubMed

    Esposito, Marisia Pannia; Pedroso, Andrea Nunes Vaz; Domingos, Marisa

    2016-04-15

    The antioxidant responses in saplings of Tibouchina pulchra (a native tree from the Brazilian Atlantic Rainforest) exposed around an oil refinery in the city of Cubatão (SE Brazil), varied during the exchange of its power generation source, from boilers fueled with oil to a thermoelectric fueled with natural gas. The redox potential changed in response to an interaction of air pollution and meteorological parameters, indicating that the pro-oxidant/antioxidant balance was not reached after the exchange of the power generation system. The gain in environmental quality in the region was not achieved as expected due the technological modernization, at least relative to oxidative stressors. These conclusions were based on results of analyses of enzymatic antioxidants: superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR); non-enzymatic antioxidants: reduced, oxidized and total ascorbic acid (AsA, DHA, totAA) and glutathione (GSH, GSSG, totG), their redox state (AsA/totAA and GSH/totG) and an indicator of lipid peroxidation (MDA). We also applied exploratory multivariate statistics in order to verify if the temporal sequence of changes in the plant redox capacity coincided with changes in the profile of air pollution, climatic conditions or with their interactions and if the environmental benefits that would supposedly be promoted by the mentioned exchange of power generation system were achieved in the region.

  4. Characterization of the adhesive areas in Sepia tuberculata (Mollusca, Cephalopoda).

    PubMed

    von Byern, Janek; Scott, Robyn; Griffiths, Charles; Micossi, Andrea; Grunwald, Ingo; Cyran, Norbert

    2011-10-01

    Adhesion in cephalopods is either mechanical, involving a reduced-pressure system of the arm and tentacle suckers, or is chemically mediated by special adhesive gland structures (as proposed for Euprymna, Idiosepius, and Nautilus). Four species of Sepia (S. typica, S. papillata, S. pulchra, and S. tuberculata) possess grooved structures on the ventral mantle surface and on the fourth arm pair, which are used to attach mechanically to the substratum. Because these areas are often partly covered with sand or debris, it has been hypothesized that chemical substances were involved in this attachment process. This study provides a histochemical and ultrastructural description of the glandular epithelium in the adhesive area of Sepia tuberculata. Two specific glandular cells (Type 1 and Type 2) are present in the epithelium, which differ clearly in their granule size and cellular structure. The aggregation of both cell types and their simultaneous secretion suggest that the secretions of both cell types work synergistically providing a two-component adhesive system which supports the primarily mechanical sucker adhesion by making the arm surface sticky.

  5. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound.

    PubMed

    Hentzer, Morten; Riedel, Kathrin; Rasmussen, Thomas B; Heydorn, Arne; Andersen, Jens Bo; Parsek, Matthew R; Rice, Scott A; Eberl, Leo; Molin, Søren; Høiby, Niels; Kjelleberg, Staffan; Givskov, Michael

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR by expression of an unstable version of the green-fluorescent protein (Gfp). Gfp-based reporter technology has been applied for non-destructive, single-cell-level detection of quorum sensing in laboratory-based P. aeruginosa biofilms. It is reported that a synthetic halogenated furanone compound, which is a derivative of the secondary metabolites produced by the Australian macroalga Delisea pulchra, is capable of interfering with AHL-mediated quorum sensing in P. aeruginosa. It is demonstrated that the furanone compound specifically represses expression of a PlasB-gfp reporter fusion without affecting growth or protein synthesis. In addition, it reduces the production of important virulence factors, indicating a general effect on target genes of the las quorum sensing circuit. The furanone was applied to P. aeruginosa biofilms established in biofilm flow chambers. The Gfp-based analysis reveals that the compound penetrates microcolonies and blocks cell signalling and quorum sensing in most biofilm cells. The compound did not affect initial attachment to the abiotic substratum. It does, however, affect the architecture of the biofilm and enhances the process of bacterial detachment, leading to a loss of bacterial biomass from the substratum.

  6. Twelve new species and fifty-three new provincial distribution records of Aleocharinae rove beetles of Saskatchewan, Canada (Coleoptera, Staphylinidae).

    PubMed

    Klimaszewski, Jan; Larson, David J; Labrecque, Myriam; Bourdon, Caroline

    2016-01-01

    One hundred twenty species of aleocharine beetles (Staphylinidae) are recognized in the province of Saskatchewan. Sixty-five new provincial records, including twelve new species and one new North American record, are presented. Oligota inflata (Mannerheim), a Palearctic species, is newly recorded for North America. The following twelve species are described as new to science: Acrotona pseudopygmaea Klimaszewski & Larson, sp. n., Agaricomorpha pulchra Klimaszewski & Larson, sp. n. (new genus record for Canadian fauna), Aleochara elisabethae Klimaszewski & Larson, sp. n., Atheta (Dimetrota) larsonae Klimaszewski & Larson, sp. n., Atheta (Microdota) pseudopittionii Klimaszewski & Larson, sp. n., Atheta (Microdota) spermathecorum Klimaszewski & Larson, sp. n., Atheta (sensu lato) richardsoni Klimaszewski & Larson, sp. n., Brachyusa saskatchewanae Klimaszewski & Larson, sp. n., Dochmonota langori Klimaszewski & Larson, sp. n., Dochmonota simulans Klimaszewski & Larson, sp. n., Dochmonota websteri Klimaszewski & Larson, sp. n., and Oxypoda domestica Klimaszewski & Larson, sp. n. Colour images of habitus and black and white images of the median lobe of the aedeagus, spermatheca, and tergite and sternite VIII are presented for all new species, Oligota inflata Mannerheim and Dochmonota rudiventris (Eppelsheim). A new synonymy is established: Tetralina filitarsus Casey, syn. n. = Tetralina helenae Casey, now placed in the genus Brachyusa Mulsant & Rey. PMID:27587977

  7. Twelve new species and fifty-three new provincial distribution records of Aleocharinae rove beetles of Saskatchewan, Canada (Coleoptera, Staphylinidae).

    PubMed

    Klimaszewski, Jan; Larson, David J; Labrecque, Myriam; Bourdon, Caroline

    2016-01-01

    One hundred twenty species of aleocharine beetles (Staphylinidae) are recognized in the province of Saskatchewan. Sixty-five new provincial records, including twelve new species and one new North American record, are presented. Oligota inflata (Mannerheim), a Palearctic species, is newly recorded for North America. The following twelve species are described as new to science: Acrotona pseudopygmaea Klimaszewski & Larson, sp. n., Agaricomorpha pulchra Klimaszewski & Larson, sp. n. (new genus record for Canadian fauna), Aleochara elisabethae Klimaszewski & Larson, sp. n., Atheta (Dimetrota) larsonae Klimaszewski & Larson, sp. n., Atheta (Microdota) pseudopittionii Klimaszewski & Larson, sp. n., Atheta (Microdota) spermathecorum Klimaszewski & Larson, sp. n., Atheta (sensu lato) richardsoni Klimaszewski & Larson, sp. n., Brachyusa saskatchewanae Klimaszewski & Larson, sp. n., Dochmonota langori Klimaszewski & Larson, sp. n., Dochmonota simulans Klimaszewski & Larson, sp. n., Dochmonota websteri Klimaszewski & Larson, sp. n., and Oxypoda domestica Klimaszewski & Larson, sp. n. Colour images of habitus and black and white images of the median lobe of the aedeagus, spermatheca, and tergite and sternite VIII are presented for all new species, Oligota inflata Mannerheim and Dochmonota rudiventris (Eppelsheim). A new synonymy is established: Tetralina filitarsus Casey, syn. n. = Tetralina helenae Casey, now placed in the genus Brachyusa Mulsant & Rey.

  8. Moss Mediates the Influence of Shrub Species on Soil Properties and Processes in Alpine Tundra

    PubMed Central

    Williamson, Scott N.; Barrio, Isabel C.; Helgadóttir, Ágústa; HiK, David S.

    2016-01-01

    In tundra ecosystems, bryophytes influence soil processes directly and indirectly through interactions with overstory shrub species. We experimentally manipulated moss cover and measured seasonal soil properties and processes under two species of deciduous shrubs with contrasting canopy structures, Salix planifolia pulchra and Betula glandulosa-nana complex. Soil properties (seasonal temperature, moisture and C:N ratios) and processes (seasonal litter decomposition and soil respiration) were measured over twelve months. Shrub species identity had the largest influence on summer soil temperatures and soil respiration rates, which were higher under Salix canopies. Mosses were associated with lower soil moisture irrespective of shrub identity, but modulated the effects of shrubs on winter soil temperatures and soil C:N ratios so that moss cover reduced differences in soil winter temperatures between shrub species and reduced C:N ratios under Betula but not under Salix canopies. Our results suggest a central role of mosses in mediating soil properties and processes, with their influence depending on shrub species identity. Such species-dependent effects need to be accounted for when forecasting vegetation dynamics under ongoing environmental changes. PMID:27760156

  9. [Low water temperature tolerance and responding mode of scleractinian corals in Sanya Bay].

    PubMed

    Li, Shu; Yu, Ke-fu; Shi, Qi; Chen, Tian-ran; Zhao, Mei-xia

    2009-09-01

    In an experimental temperature-regulated mesocosm, the low water temperature tolerance of five dominant scleractinian coral species Pavona decussate, Acropora pulchra, Acropora florida, Acropora valida, and Porites lutea in Sanya Bay was investigated, and their responding modes to the cold water stress were analyzed. The tolerance of test corals to low water temperature was closely related to their morphologies, with the branching corals being the most vulnerable to bleaching and death by separating the symbiotic polyps from their skeletons. The lethal low water temperature for branching Acropora corals was 14 degrees C lasting for 3 days, and that for foliose P. decussate was 12 degrees C lasting for 10 days. Massive P. lutea corals responded to low water temperature by forming mucus membrane, which helped to prevent the further losing of symbiotic algae. The corals showing strong tolerance to high water temperature also had strong tolerance to low water temperature, and had similar responding modes to both high and low water temperature, i.e., the corals didn't extend their tentacle first, followed by the continuous release of mucus and the discharge of symbiotic zooxanthellae, and finally, bleached and died.

  10. The cell's view of animal body-plan evolution.

    PubMed

    Lyons, Deirdre C; Martindale, Mark Q; Srivastava, Mansi

    2014-10-01

    An adult animal's form is shaped by the collective behavior of cells during embryonic development. To understand the forces that drove the divergence of animal body-plans, evolutionary developmental biology has focused largely on studying genetic networks operating during development. However, it is less well understood how these networks modulate characteristics at the cellular level, such as the shape, polarity, or migration of cells. We organized the "Cell's view of animal body plan evolution" symposium for the 2014 The Society for Integrative and Comparative Biology meeting with the explicit goal of bringing together researchers studying the cell biology of embryonic development in diverse animal taxa. Using a broad range of established and emerging technologies, including live imaging, single-cell analysis, and mathematical modeling, symposium participants revealed mechanisms underlying cells' behavior, a few of which we highlight here. Shape, adhesion, and movements of cells can be modulated over the course of evolution to alter adult body-plans and a major theme explored during the symposium was the role of actomyosin in coordinating diverse behaviors of cells underlying morphogenesis in a myriad of contexts. Uncovering whether conserved or divergent genetic mechanisms guide the contractility of actomyosin in these systems will be crucial to understanding the evolution of the body-plans of animals from a cellular perspective. Many speakers presented research describing developmental phenomena in which cell division and tissue growth can control the form of the adult, and other presenters shared work on studying cell-fate specification, an important source of novelty in animal body-plans. Participants also presented studies of regeneration in annelids, flatworms, acoels, and cnidarians, and provided a unifying view of the regulation of cellular behavior during different life-history stages. Additionally, several presentations highlighted technological

  11. The cell's view of animal body-plan evolution.

    PubMed

    Lyons, Deirdre C; Martindale, Mark Q; Srivastava, Mansi

    2014-10-01

    An adult animal's form is shaped by the collective behavior of cells during embryonic development. To understand the forces that drove the divergence of animal body-plans, evolutionary developmental biology has focused largely on studying genetic networks operating during development. However, it is less well understood how these networks modulate characteristics at the cellular level, such as the shape, polarity, or migration of cells. We organized the "Cell's view of animal body plan evolution" symposium for the 2014 The Society for Integrative and Comparative Biology meeting with the explicit goal of bringing together researchers studying the cell biology of embryonic development in diverse animal taxa. Using a broad range of established and emerging technologies, including live imaging, single-cell analysis, and mathematical modeling, symposium participants revealed mechanisms underlying cells' behavior, a few of which we highlight here. Shape, adhesion, and movements of cells can be modulated over the course of evolution to alter adult body-plans and a major theme explored during the symposium was the role of actomyosin in coordinating diverse behaviors of cells underlying morphogenesis in a myriad of contexts. Uncovering whether conserved or divergent genetic mechanisms guide the contractility of actomyosin in these systems will be crucial to understanding the evolution of the body-plans of animals from a cellular perspective. Many speakers presented research describing developmental phenomena in which cell division and tissue growth can control the form of the adult, and other presenters shared work on studying cell-fate specification, an important source of novelty in animal body-plans. Participants also presented studies of regeneration in annelids, flatworms, acoels, and cnidarians, and provided a unifying view of the regulation of cellular behavior during different life-history stages. Additionally, several presentations highlighted technological

  12. Identification, Characterization, and Diel Pattern of Expression of Canonical Clock Genes in Nephrops norvegicus (Crustacea: Decapoda) Eyestalk.

    PubMed

    Sbragaglia, Valerio; Lamanna, Francesco; M Mat, Audrey; Rotllant, Guiomar; Joly, Silvia; Ketmaier, Valerio; de la Iglesia, Horacio O; Aguzzi, Jacopo

    2015-01-01

    The Norway lobster, Nephrops norvegicus, is a burrowing decapod with a rhythmic burrow emergence (24 h) governed by the circadian system. It is an important resource for European fisheries and its behavior deeply affects its availability. The current knowledge of Nephrops circadian biology is phenomenological as it is currently the case for almost all crustaceans. In attempt to elucidate the putative molecular mechanisms underlying circadian gene regulation in Nephrops, we used a transcriptomics approach on cDNA extracted from the eyestalk, a structure playing a crucial role in controlling behavior of decapods. We studied 14 male lobsters under 12-12 light-darkness blue light cycle. We used the Hiseq 2000 Illumina platform to sequence two eyestalk libraries (under light and darkness conditions) obtaining about 90 millions 100-bp paired-end reads. Trinity was used for the de novo reconstruction of transcriptomes; the size at which half of all assembled bases reside in contigs (N50) was equal to 1796 (light) and 2055 (darkness). We found a list of candidate clock genes and focused our attention on canonical ones: timeless, period, clock and bmal1. The cloning of assembled fragments validated Trinity outputs. The putative Nephrops clock genes showed high levels of identity (blastx on NCBI) with known crustacean clock gene homologs such as Eurydice pulchra (period: 47%, timeless: 59%, bmal1: 79%) and Macrobrachium rosenbergii (clock: 100%). We also found a vertebrate-like cryptochrome 2. RT-qPCR showed that only timeless had a robust diel pattern of expression. Our data are in accordance with the current knowledge of the crustacean circadian clock, reinforcing the idea that the molecular clockwork of this group shows some differences with the established model in Drosophila melanogaster.

  13. Unusually high food availability in Kaikoura Canyon linked to distinct deep-sea nematode community

    NASA Astrophysics Data System (ADS)

    Leduc, D.; Rowden, A. A.; Nodder, S. D.; Berkenbusch, K.; Probert, P. K.; Hadfield, M. G.

    2014-06-01

    Kaikoura Canyon, on the eastern New Zealand continental margin, is the most productive, non-chemosynthetic deep-sea habitat described to date, with megafaunal biomass 100-fold higher than those of other deep-sea habitats. The present study, which focused on free-living nematodes, provides the first comparison of faunal community structure and diversity between Kaikoura Canyon and nearby open slope habitats. Results show substantially higher food availability in the canyon relative to open slope sediments, which probably reflects greater levels of primary productivity above the canyon, coupled with downwelling and/or topographically-induced channelling, which serves to concentrate surface-derived organic matter along the canyon axis. This high food availability appears to be responsible for the elevated nematode biomass in Kaikoura Canyon, with values exceeding all published nematode biomass data from canyons elsewhere. There was also markedly lower local species diversity of nematodes inside the canyon relative to the open slope habitat, as well as a distinct community structure. The canyon community was dominated by species, such as Sabateria pulchra, which were absent from the open slope and are typically associated with highly eutrophic and/or disturbed environments. The presence of these taxa, as well as the low observed diversity, is likely to reflect the high food availability, and potentially the high levels of physically and biologically induced disturbance within the canyon. Kaikoura Canyon is a relatively small habitat characterised by different environmental conditions that makes a disproportionate contribution to deep-sea diversity in the region, despite its low species richness.

  14. Experimental biological effects assessment associated with on-shore brine discharge from the creation of gas storage caverns

    NASA Astrophysics Data System (ADS)

    Quintino, Victor; Rodrigues, Ana Maria; Freitas, Rosa; Ré, Ana

    2008-09-01

    Most of the studies on biological and ecological effects associated with brine discharge into the marine environment are related to the operation of desalination plants, for the production of freshwater. In this study we analysed the biological effects of a brine effluent from a completely different source, produced from the lixiviation of rock salt caves, for the creation of natural gas storage caverns. Lethal and sub-lethal endpoints following exposure to the brine were studied in a range of macrofauna species characteristic of the soft and hard bottom habitats in the vicinity of the discharge area, namely the isopod Eurydice pulchra, the annelids Sabellaria alveolata and Ophelia radiata, the sea-urchin Paracentrotus lividus and the bivalve Mytilus galloprovincialis. In a first series of experiments, brine, with salinity above 300, was diluted in distilled water to a salinity value close to that of the seawater in the discharge area (salinity 36) and, surprisingly, none of the exposed species was able to survive or develop into viable larvae. A second series of experiments exposed the species to brine diluted with seawater, simulating more realistic discharge circumstances. All the tested species at all the measured endpoints (adult survival, larval abnormal development, sperm fertilization success) showed negative biological effects in brine solutes always at a lower salinity than that of a salinity control obtained with concentrated seawater. The sub-lethal experiments with larval development of P. lividus, S. alveolata and M. galloprovincialis, and the fertilization success of P. lividus gave EC 50 values for the brine solute with salinity in the range of 40.9-43.5, whereas the EC 50 values for the concentrated seawater were in the range of salinity 44.2-49.0. It is hypothesised that differences in the ionic composition of the brine cause the inability of the species to tolerate the exposure to brine.

  15. Evolution of Surface Water Conditions in the Gulf of California During the Past 2000 years: Implications for the North American Monsoon

    NASA Astrophysics Data System (ADS)

    Barron, J. A.; Bukry, D.; Addison, J. A.; McGann, M.; Schwartz, V.; McGeehin, J. P.; McClymont, E.

    2015-12-01

    High-resolution analyses of diatoms, silicoflagellates, biogenic silica, and alkenones in laminated sediment cores from the Guaymas Basin (central Gulf of California) reveal pronounced changes in surface water conditions over the past 2000 years. Prior to ~AD 1200, surface waters in the western Guaymas Basin (boxcore MD02-2517c2 at 27.4850° N, 112.0743°W, water depth 887 m) were characterized by high biologic productivity with alternating assemblages of productive diatoms (Thalassionema nitzschioides, Fragilariopsis doliolus) and silicoflagellates (Octactis pulchra, Dictyocha stapedia). Beginning at ~ AD 1200 productivity declined abruptly in two steps (at ~AD 1200 and ~1500) that were marked by increases in the relative abundance of tropical diatoms and silicoflagellates. In contrast, eastern Guaymas Basin Kasten Core BAM80 E-17 (27.920° N, 111.610°W, 620 m of water depth), was dominated by high biosiliceous productivity during the past 2000 years with increases corresponding to solar minima, arguing that an intensification of winter northwest winds drove coastal upwelling. In both Guaymas Basin records silicoflagellate assemblages suggest surface-water cooling during Medieval Climate Anomaly (MCA; ~AD 800-1200) relative to the intervals before and after. Together, these records support a cooler La Niña-like MCA followed by a warmer El Niño-like Little Ice Age, similar to results obtained from the Santa Barbara Basin to the north. During La Niñas, the Intertropical Convergence Zone (ITCZ) occupies a more northerly position in the eastern tropical Pacific, facilitating summertime surges of Pacific tropical moisture up the Gulf and higher monsoonal precipitation in the southwestern US. A modeling study by Song Feng et al. (2008, JGR) of the broader MCA (AD 800-1300) utilizes La Niña-like Pacific sea surface temperatures to argues for an intensified North American Monsoon during the MCA. Limited terrestrial proxy records from Arizona and New Mexico are

  16. Stage-dependent border cell and carbon flow from roots to rhizosphere.

    PubMed

    Odell, Ryan E; Dumlao, Matthew R; Samar, Danial; Silk, Wendy K

    2008-04-01

    Rising CO(2) levels in the atmosphere have drawn attention to the important role of soil in sequestering carbon. This project goal was to quantify soil carbon deposition associated with border cell release and exudation from root growth zones. Carbon was measured with a Carlo Erba C/N analyzer in soil from the rhizosphere of mature grasses and, in separate experiments, in soil collected around root growth zones. Root border cells in "rhizosphere soil" (silica sand) were counted using a compound microscope after soil sonication and extraction with surfactant. For sand-grown Bromus carinatus, Zea mays, and Cucumis sativus, young seedlings (with roots shorter than 2 cm) released thousands of border cells, while older root tips released only hundreds. For a variety of native annual and perennial grasses and invasive annual grasses (Nassella pulchra, B. carinatus, B. diandrus, B. hordeaceus, Vulpia microstachys, Aegilops triuncialis, Lolium multiflorum, Zea mays), the rhizosphere of mature root systems contained between 18 and 32 μg C g(-1) sand more than that of the unplanted controls. Spatial analysis of the rhizosphere around the cucumber growth zone confirmed C enrichment there. The root tip provided C to the rhizosphere: 4.6 μg C in front of the growing tip, with the largest deposition, 20.4 μg C, to the rhizosphere surrounding the apical 3 mm (root cap/meristem). These numbers from laboratory studies represent the maximum C that might be released during flooding in soils. Scaling up from the organ scale to the field requires a growth analysis to quantify root tip distributions in space and time.

  17. Species composition and seasonal abundance of Chaetognatha in the subtropical coastal waters of Hong Kong

    NASA Astrophysics Data System (ADS)

    Tse, P.; Hui, S. Y.; Wong, C. K.

    2007-06-01

    Species composition, species diversity and seasonal abundance of chaetognaths were studied in Tolo Harbour and the coastal waters of eastern Hong Kong. Tolo Harbour is a semi-enclosed and poorly flushed bay with a long history of eutrophication. It opens into the eastern coast of Hong Kong which is fully exposed to water currents from the South China Sea. Zooplankton samples were collected monthly from July 2003 to July 2005 at six stations. Twenty species of chaetognaths were identified. They included six species of the genus Aidanosagitta ( Aidanosagitta neglecta, Aidanosagitta delicata, Aidanosagitta johorensis, Aidanosagitta regularis, Aidanosagitta bedfordii and Aidanosagitta crassa), four species of the genus Zonosagitta ( Zonosagitta nagae, Zonosagitta bedoti, Zonosagitta bruuni and Zonosagitta pulchra), three species of the genus Ferosagitta ( Ferosagitta ferox, Ferosagitta tokiokai and Ferosagitta robusta) and one species each from the genera Serratosagitta ( Serratosagitta pacifica), Decipisagitta ( Decipisagitta decipiens), Flaccisagitta ( Flaccisagitta enflata), Krohnitta ( Krohnitta pacifica), Mesosagitta ( Mesosagitta minima), Pterosagitta ( Pterosagitta draco) and Sagitta ( Sagitta bipunctata). The most abundant species were Flaccisagitta enflata, A. neglecta and A. delicata. Averaged over the entire study period, the densities of Flaccisagitta enflata, A. neglecta and A. delicata were 9.3, 6.6 and 5.2 ind. m -3, respectively. Overall, these species constituted 39.7%, 28.2% and 22.0% of all chaetognaths collected in the study. Averaged over the entire study, the density of most of the low abundance species was <0.6 ind. m -3. Flaccisagitta enflata occurred throughout the year at all sampling stations. Aidanosagitta neglecta occurred at all sampling stations, but was most common in summer. Aidanosagitta delicata was most common in Tolo Harbour during summer. Tolo Harbour supported larger populations, but fewer species of chaetognaths than the

  18. Inferring extinction of mammals from sighting records, threats, and biological traits.

    PubMed

    Fisher, Diana O; Blomberg, Simon P

    2012-02-01

    For species with five or more sightings, quantitative techniques exist to test whether a species is extinct on the basis of distribution of sightings. However, 70% of purportedly extinct mammals are known from fewer than five sightings, and such models do not include some important indicators of the likelihood of extinction such as threats, biological traits, search effort, and demography. Previously, we developed a quantitative method that we based on species' traits in which we used Cox proportional hazards regression to calculate the probability of rediscovery of species regarded as extinct. Here, we used two versions of the Cox regression model to determine the probability of extinction in purportedly extinct mammals and compared the results of these two models with those of stationary Poisson, nonparametric, and Weibull sighting-distribution models. For mammals with five or more sightings, the stationary Poisson model categorized all but two critically endangered (flagged as possibly extinct) species in our data set as extinct, and results with this model were consistent with current categories of the International Union for the Conservation of Nature. The scores of probability of rediscovery for individual species in one version of our Cox regression model were correlated with scores assigned by the stationary Poisson model. Thus, we used this Cox regression model to determine the probability of extinction of mammals with sparse records. On the basis of the Cox regression model, the most likely mammals to be rediscovered were the Montane monkey-faced bat (Pteralopex pulchra), Armenian myotis (Myotis hajastanicus), Alcorn's pocket gopher (Pappogeomys alcorni), and Wimmer's shrew (Crocidura wimmeri). The Cox model categorized two species that have recently disappeared as extinct: the baiji (Lipotes vexillifer) and the Christmas Island pipistrelle (Pipistrellus murrayi). Our new method can be used to test whether species with few records or recent last

  19. Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.

    PubMed

    Khorsand Rosa, Roxaneh; Oberbauer, Steven F; Starr, Gregory; Parker La Puma, Inga; Pop, Eric; Ahlquist, Lorraine; Baldwin, Tracey

    2015-12-01

    Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover

  20. Tidal exchange of zooplankton between Lough Hyne and the adjacent coast

    NASA Astrophysics Data System (ADS)

    Rawlinson, K. A.; Davenport, J.; Barnes, D. K. A.

    2005-01-01

    Plankton samples collected in November 2002, February, May and August 2003 were used to examine seasonal variation in tidal exchange of zooplankton biomass, abundance and species composition between Lough Hyne Marine Nature Reserve and the adjacent Atlantic coast. Micro- to mesozooplankton were collected by pump over 24-h sampling periods during spring and neap tides from the narrow channel connecting the semi-enclosed water body to the Atlantic. Sample biomass (dry weight) and total zooplankton abundance peaked in the summer and were lowest in winter, showing a positive relationship with temperature. Zooplankton biomass, total abundance and numbers of holo- and meroplankton revealed import during some diel cycles and export in others. However, the tidal import of these planktonic components was generally dominant, especially during May. The greatest import of numbers of holoplankters and meroplanktonic larvae occurred during May and August, respectively. There was no significant variation in sample biomass between periods of light and dark, but some variation in zooplankton abundance could be explained by this diel periodicity. Significant differences in sample assemblage composition between flood and ebb tide samples were always observed, except during winter neap tides. There was a net import of the copepods Temora longicornis and Oithona helgolandica and the larval stages of Mytilus edulis during spring and summer. Proceraea cornuta and Capitellid trochophores were imported during winter, and a hydrozoan of the genus Obelia during the spring spring tides. Seasonal export from the lough was shown by Pseudopolydora pulchra larvae (autumn and spring), Serpulid trochophores (autumn) and veligers of the bivalve Anomia ephippium (summer). It is suggested that the direction of tidal exchange of meroplanktonic taxa is related to the distribution of the adult populations. Copepod naupliar stages dominated the assemblages except during May spring tides when the copepod

  1. Identification, Characterization, and Diel Pattern of Expression of Canonical Clock Genes in Nephrops norvegicus (Crustacea: Decapoda) Eyestalk

    PubMed Central

    Sbragaglia, Valerio; Lamanna, Francesco; M. Mat, Audrey; Rotllant, Guiomar; Joly, Silvia; Ketmaier, Valerio; de la Iglesia, Horacio O.; Aguzzi, Jacopo

    2015-01-01

    The Norway lobster, Nephrops norvegicus, is a burrowing decapod with a rhythmic burrow emergence (24 h) governed by the circadian system. It is an important resource for European fisheries and its behavior deeply affects its availability. The current knowledge of Nephrops circadian biology is phenomenological as it is currently the case for almost all crustaceans. In attempt to elucidate the putative molecular mechanisms underlying circadian gene regulation in Nephrops, we used a transcriptomics approach on cDNA extracted from the eyestalk, a structure playing a crucial role in controlling behavior of decapods. We studied 14 male lobsters under 12–12 light-darkness blue light cycle. We used the Hiseq 2000 Illumina platform to sequence two eyestalk libraries (under light and darkness conditions) obtaining about 90 millions 100-bp paired-end reads. Trinity was used for the de novo reconstruction of transcriptomes; the size at which half of all assembled bases reside in contigs (N50) was equal to 1796 (light) and 2055 (darkness). We found a list of candidate clock genes and focused our attention on canonical ones: timeless, period, clock and bmal1. The cloning of assembled fragments validated Trinity outputs. The putative Nephrops clock genes showed high levels of identity (blastx on NCBI) with known crustacean clock gene homologs such as Eurydice pulchra (period: 47%, timeless: 59%, bmal1: 79%) and Macrobrachium rosenbergii (clock: 100%). We also found a vertebrate-like cryptochrome 2. RT-qPCR showed that only timeless had a robust diel pattern of expression. Our data are in accordance with the current knowledge of the crustacean circadian clock, reinforcing the idea that the molecular clockwork of this group shows some differences with the established model in Drosophila melanogaster. PMID:26524198

  2. Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.

    PubMed

    Khorsand Rosa, Roxaneh; Oberbauer, Steven F; Starr, Gregory; Parker La Puma, Inga; Pop, Eric; Ahlquist, Lorraine; Baldwin, Tracey

    2015-12-01

    Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover

  3. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

    USGS Publications Warehouse

    Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

    2006-01-01

    Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

  4. Taxonomist’s Nightmare … Evolutionist’s Delight †: An Integrative Approach Resolves Species Limits in Jumping Bristletails Despite Widespread Hybridization and Parthenogenesis

    PubMed Central

    Dejaco, Thomas; Gassner, Melitta; Arthofer, Wolfgang; Schlick-Steiner, Birgit C.; Steiner, Florian M.

    2016-01-01

    Accurate species delimitation is fundamental to biology. Traditionally, species were delimited based on morphological characters, sometimes leading to taxonomic uncertainty in morphologically conserved taxa. Recently, multiple taxonomically challenging cases have benefited from integrative taxonomy—an approach that highlights congruence among different disciplines and invokes evolutionary explanations for incongruence, acknowledging that different methods can mirror different stages of the speciation continuum. Here, we used a cohesive protocol for integrative taxonomy to revise species limits in 20 nominal species and 4 morphospecies of an ancestrally wingless insect group, the jumping bristletail genus Machilis from the European Eastern Alps. Even though morphologically conserved, several small-scale endemic species have been described from the Eastern Alps based on variation in hypodermal pigmentation patterns—a highly questionable character. As valuable as these endemics are for conservation, they have never been verified by alternative methods. Using traditional morphometrics, mitochondrial DNA, ribosomal DNA, and amplified fragment-length polymorphism markers, we identify six nominal species as taxonomic junior synonyms (Machilis alpicola Janetschek, 1953 syn. n. under M. vagans Wygodzinsky, 1941; M. ladensis Janetschek, 1950 syn. n., M. robusta Wygodzinsky, 1941 syn. n., and M. vicina Wygodzinsky, 1941 syn. n. under M. inermis Wygodzinsky, 1941; M. aleamaculata Wygodzinsky, 1941 syn. n. under M. montana Wygodzinsky, 1941; M. pulchra Janetschek, 1950 syn. n. under M. helleri Verhoeff, 1910) and describe two new species (Machilis cryptoglacialis sp. n. and Machilis albida sp. n.), one uncovered from morphological crypsis and one never sampled before. Building on numerous cases of incongruence among data sources, we further shed light on complex evolutionary histories including hybrid speciation, historical and recent hybridization, and ongoing speciation

  5. Annotated type catalogue of the Chrysididae (Insecta, Hymenoptera) deposited in the collection of Radoszkowski in the Polish Academy of Sciences, Kraków

    PubMed Central

    Rosa, Paolo; Wiśniowski, Bogdan; Xu, Zai-fu

    2015-01-01

    Abstract A critical and annotated catalogue of 183 types of Hymenoptera Chrysididae belonging to 124 taxa housed in the Radoszkowski collection is given. Radoszkowski type material from other institutes has also been checked. Six lectotypes are designated in Kraków (ISEA-PAN): Chrysis acceptabilis Radoszkowski, 1891; Chrysis persica Radoczkowsky, 1881; Chrysis daphnis Mocsáry, 1889; Chrysis lagodechii Radoszkowski, 1889; Chrysis remota Mocsáry, 1889 and Chrysis vagans Radoszkowski, 1877. The lectotype of Brugmoia pellucida Radoszkowski, 1877 is designated in Moscow (MMU). Four new combinations are proposed: Philoctetes araraticus (Radoszkowski, 1890), comb. n.; Pseudomalus hypocrita (du Buysson, 1893), comb. n.; Chrysis eldari (Radoszkowski, 1893), comb. n.; and Chrysura mlokosewitzi (Radoszkowski, 1889), comb. n.. Ten new synonyms are given: Chrysis auropunctata Mocsáry, 1889, syn. n. of Chrysis angolensis Radoszkovsky, 1881; Chrysis chrysochlora Mocsáry, 1889, syn. n. and Chrysis viridans Radoszkowski, 1891, syn. n. of Chrysis keriensis Radoszkowski, 1887; Chrysis angustifrons var. ignicollis Trautmann, 1926, syn. n. of Chrysis eldari (Radoszkowski, 1893); Chrysis maracandensis var. simulatrix Radoszkowski, 1891, syn. n. of Chrysis maracandensis Radoszkowski, 1877; Chrysis pulchra Radoszkovsky, 1880, syn. n. of Spinolia dallatorreana (Mocsáry, 1896); Chrysis rubricollis du Buysson, 1900, syn. n. of Chrysis eldari (Radoszkowski, 1893); Chrysis subcoerulea Radoszkowski, 1891, syn. n. of Chrysis chlorochrysa Mocsáry, 1889; Chrysis therates Mocsáry, 1889, syn. n. of Chrysis principalis Smith, 1874; and Notozus komarowi Radoszkowski, 1893, syn. n. of Elampus obesus (Mocsáry, 1890). One species is revaluated: Chrysis chalcochrysa Mocsáry, 1887. Chrysis kizilkumiana Rosa is the new name for Chrysis uljanini Radoszkowski & Mocsáry, 1889 nec Radoszkowski, 1877. Pictures of seventy-seven type specimens are given. PMID:25829848

  6. Increasing NDVI values in northern Alaska: studies that mix shrub density, spectral and CO2 exchange measurements

    NASA Astrophysics Data System (ADS)

    Anderson-Smith, A.; Lewis, A.; Sullivan, P.; Welker, J. M.

    2010-12-01

    Delineating the mechanisms and consequences of changes in tundra landscapes is central to predicting the functional ecology of Alaska in the 21st Century. Evidence has been mounting during the last decade that shrub communities are expanding in the Arctic and Normalized Difference Vegetation Index (NDVI) values which measure surface greenness are rising. Several studies have suggested that NDVI increases are being driven by increases in shrub abundance. While it is clear that NDVI has increased across vegetation types, it is not clear that NDVI values are increasing in moist acidic tundra (MAT), the most extensive vegetation type in arctic Alaska and the one most likely to be changed by global warming. The MAT is important to large mammal herbivores such as caribou which provide subsistence for indigenous people. The focus of this research was to determine what rising NDVI values actually mean in the MAT. The degree to which tundra community composition affects NDVI is still very poorly understood. In order to clarify the role of shrub encroachment per se as opposed to other functional groups in driving increases in NDVI, we measured functional group composition in moist acidic tundra in conjunction with hand-held measures of NDVI and direct CO2 exchange measurements to explicitly link spectral properties, shrub, graminoid and bryophyte density and trace gas feedbacks to atmospheric chemistry. Point frame data shows a shrub coverage of Betula nana (Dwarf Birch) and Salix pulchra (Diamond Leaf Willow) combined of 5% to 35% in MAT. Our results seem to indicate that high shrub density (>30%) corresponds to peak season NDVI values greater than .75 whereas low shrub density correspond to values below .65 (R2=.66). Furthermore, NDVI is closely correlated with canopy leaf area and greater leaf area is associated with higher rates of gross and net ecosystem CO2 uptake.

  7. The effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone on the pressure overload-induced progression of cardiac hypertrophy to cardiac failure.

    PubMed

    Huang, Jianchun; Tang, XiaoJun; Liang, Xingmei; Wen, Qingwei; Zhang, Shijun; Xuan, Feifei; Jian, Jie; Lin, Xing; Huang, Renbin

    2014-01-01

    We investigated the effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC), which was isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z.Wei (Papilionaceae) (MKL), on the progression of cardiac hypertrophy to failure in a rat model of abdominal aortic banding (AAB)-induced pressure overloading. Endothelial dysfunction is central to pressure overload-induced cardiac hypertrophy and failure. It would be useful to clarify whether MHBFC could prevent this dysfunction. The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using the progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats exhibited a greater progression to heart failure and had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, and evidence of left ventricular hypertrophy (LVH). LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These symptoms could be prevented by treatment with MHBFC at daily oral doses of 6 and 12 mg/kg for 6 weeks. The progression to cardiac failure, which was demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial natriuretic peptide (ANP) mRNA, could also be prevented. Furthermore, MHBFC partialy rescued the downregulated nitric oxide signaling system, whereas inhibited the upregulated endothelin signaling system, normalizing the balance between these two systems. MHBFC protected the endothelium and prevented the pressure overload-induced progression of cardiac hypertrophy to cardiac failure. PMID:24622486

  8. The Effects of 17-Methoxyl-7-Hydroxy-Benzene-Furanchalcone on the Pressure Overload-Induced Progression of Cardiac Hypertrophy to Cardiac Failure

    PubMed Central

    Liang, Xingmei; Wen, Qingwei; Zhang, Shijun; Xuan, Feifei; Jian, Jie; Lin, Xing; Huang, Renbin

    2014-01-01

    We investigated the effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC), which was isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z.Wei (Papilionaceae) (MKL), on the progression of cardiac hypertrophy to failure in a rat model of abdominal aortic banding (AAB)-induced pressure overloading. Endothelial dysfunction is central to pressure overload-induced cardiac hypertrophy and failure. It would be useful to clarify whether MHBFC could prevent this dysfunction. The effects of pressure overload were assessed in male Sprague–Dawley rats 6 weeks after AAB using the progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats exhibited a greater progression to heart failure and had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, and evidence of left ventricular hypertrophy (LVH). LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These symptoms could be prevented by treatment with MHBFC at daily oral doses of 6 and 12 mg/kg for 6 weeks. The progression to cardiac failure, which was demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial natriuretic peptide (ANP) mRNA, could also be prevented. Furthermore, MHBFC partialy rescued the downregulated nitric oxide signaling system, whereas inhibited the upregulated endothelin signaling system, normalizing the balance between these two systems. MHBFC protected the endothelium and prevented the pressure overload-induced progression of cardiac hypertrophy to cardiac failure. PMID:24622486

  9. Long-term deeper snow causes changes in litter quality, soil C and N storage in moist acidic tundra in Northern Alaska

    NASA Astrophysics Data System (ADS)

    Miller, O.; Xu, D.; Gonzalez-Meler, M. A.; Welker, J. M.; Filley, T. R.

    2013-12-01

    Tundra ecosystems store over one third of the global terrestrial organic C pool and have the potential to release large amounts of CO2 as organic matter decomposition is expected to increase as climate warms and precipitation changes. However, a warming climate and increased snow pack soil thermal insulation is expected to shift dominant vegetative cover type affecting above and below ground litter quality, soil organic matter storage depth, and decomposition rates in respective soils. These changes can affect the magnitude and even direction of soil C storage in the Arctic tundra.. At a sixteen-year snow fence experiment at Toolik Lake, as part of the International Tundra Experiment (ITEX), increased snow pack resulted in a shift from a Sphagnum moss-dominated mixed graminoid-deciduous ecosystem (moist tussock tundra) to one covered largely by deciduous shrubs and Carex in more water-saturated soil conditions. We investigated relationships between shifting dominance of plant species and impacts to soils using a multiproxy isotope and biomarker approach in plants and soils from the areas with control, deep, intermediate, and low snow pack. A comparison of the same plant species (Betula nana, Carex bigelowii, Eriophorum vaginatum, Salix pulchra, and Sphagnum spp.) along the snow zones showed leaf tissue C-to-N ratio decreasing in the deep snow areas when compared to control and low snow pack areas, driven by an increase in plant N content. Root and stem tissue was impacted similarly across the experimental treatments. Changes in soil δ13C and δ15N values with depth and along the transect demonstrate impacts to C and N cycling. These results demonstrate litter quality and soil carbon storage feedbacks in response to snow pack thermal insulation that could influence litter accumulation, decay rates and the chemical nature of soil carbon under climate conditions with deeper snow in winter.

  10. Identification, Characterization, and Diel Pattern of Expression of Canonical Clock Genes in Nephrops norvegicus (Crustacea: Decapoda) Eyestalk.

    PubMed

    Sbragaglia, Valerio; Lamanna, Francesco; M Mat, Audrey; Rotllant, Guiomar; Joly, Silvia; Ketmaier, Valerio; de la Iglesia, Horacio O; Aguzzi, Jacopo

    2015-01-01

    The Norway lobster, Nephrops norvegicus, is a burrowing decapod with a rhythmic burrow emergence (24 h) governed by the circadian system. It is an important resource for European fisheries and its behavior deeply affects its availability. The current knowledge of Nephrops circadian biology is phenomenological as it is currently the case for almost all crustaceans. In attempt to elucidate the putative molecular mechanisms underlying circadian gene regulation in Nephrops, we used a transcriptomics approach on cDNA extracted from the eyestalk, a structure playing a crucial role in controlling behavior of decapods. We studied 14 male lobsters under 12-12 light-darkness blue light cycle. We used the Hiseq 2000 Illumina platform to sequence two eyestalk libraries (under light and darkness conditions) obtaining about 90 millions 100-bp paired-end reads. Trinity was used for the de novo reconstruction of transcriptomes; the size at which half of all assembled bases reside in contigs (N50) was equal to 1796 (light) and 2055 (darkness). We found a list of candidate clock genes and focused our attention on canonical ones: timeless, period, clock and bmal1. The cloning of assembled fragments validated Trinity outputs. The putative Nephrops clock genes showed high levels of identity (blastx on NCBI) with known crustacean clock gene homologs such as Eurydice pulchra (period: 47%, timeless: 59%, bmal1: 79%) and Macrobrachium rosenbergii (clock: 100%). We also found a vertebrate-like cryptochrome 2. RT-qPCR showed that only timeless had a robust diel pattern of expression. Our data are in accordance with the current knowledge of the crustacean circadian clock, reinforcing the idea that the molecular clockwork of this group shows some differences with the established model in Drosophila melanogaster. PMID:26524198

  11. Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans.

    PubMed

    Estrada, Marta; Delgado, Maximino; Blasco, Dolors; Latasa, Mikel; Cabello, Ana María; Benítez-Barrios, Verónica; Fraile-Nuez, Eugenio; Mozetič, Patricija; Vidal, Montserrat

    2016-01-01

    We examine the large-scale distribution patterns of the nano- and microphytoplankton collected from 145 oceanic stations, at 3 m depth, the 20% light level and the depth of the subsurface chlorophyll maximum, during the Malaspina-2010 Expedition (December 2010-July 2011), which covered 15 biogeographical provinces across the Atlantic, Indian and Pacific oceans, between 35°N and 40°S. In general, the water column was stratified, the surface layers were nutrient-poor and the nano- and microplankton (hereafter phytoplankton, for simplicity, although it included also heterotrophic protists) community was dominated by dinoflagellates, other flagellates and coccolithophores, while the contribution of diatoms was only important in zones with shallow nutriclines such as the equatorial upwelling regions. We applied a principal component analysis to the correlation matrix among the abundances (after logarithmic transform) of the 76 most frequent taxa to synthesize the information contained in the phytoplankton data set. The main trends of variability identified consisted of: 1) A contrast between the community composition of the upper and the lower parts of the euphotic zone, expressed respectively by positive or negative scores of the first principal component, which was positively correlated with taxa such as the dinoflagellates Oxytoxum minutum and Scrippsiella spp., and the coccolithophores Discosphaera tubifera and Syracosphaera pulchra (HOL and HET), and negatively correlated with taxa like Ophiaster hydroideus (coccolithophore) and several diatoms, 2) a general abundance gradient between phytoplankton-rich regions with high abundances of dinoflagellate, coccolithophore and ciliate taxa, and phytoplankton-poor regions (second principal component), 3) differences in dominant phytoplankton and ciliate taxa among the Atlantic, the Indian and the Pacific oceans (third principal component) and 4) the occurrence of a diatom-dominated assemblage (the fourth principal

  12. Environmental Limits of Tall Shrubs in Alaska's Arctic National Parks.

    PubMed

    Swanson, David K

    2015-01-01

    We sampled shrub canopy volume (height times area) and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss) on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this information to predict the location of future shrub expansion. The study area covers over 80,000 km2 and has mostly tundra vegetation. Large canopy volumes were uncommon, with volumes over 0.5 m3/m2 present on just 8% of plots. Shrub canopy volumes were highest where mean July temperatures were above 10.5°C and on weakly acid to neutral soils (pH of 6 to 7) with deep summer thaw (>80 cm) and good drainage. On many sites, flooding helped maintain favorable soil conditions for shrub growth. Canopy volumes were highest where the typical snow loss date was near 20 May; these represent sites that are neither strongly wind-scoured in the winter nor late to melt from deep snowdrifts. Individual species varied widely in the canopy volumes they attained and their response to the environmental factors. Betula sp. shrubs were the most common and quite tolerant of soil acidity, cold July temperatures, and shallow thaw depths, but they did not form high-volume canopies under these conditions. Alnus viridis formed the largest canopies and was tolerant of soil acidity down to about pH 5, but required more summer warmth (over 12°C) than the other species. The Salix species varied widely from S. pulchra, tolerant of wet and moderately acid soils, to S. alaxensis, requiring well-drained soils with near neutral pH. Nearly half of the land area in ARCN has mean July temperatures of 10.5 to 12.5°C, where 2°C of warming would bring temperatures into the range needed for all of the potential tall shrub species to form large canopies. However, limitations in the other environmental factors would probably prevent the formation of large shrub canopies

  13. Biostratigraphical, paleoecological and paleobiogeographical interest of Guembelitria species across the Cretaceous-Paleogene transition at Atlantic realm (Bidart, SW France) and comparaison with Tethys realm

    NASA Astrophysics Data System (ADS)

    Gallala, N.; Zaghbib-Turki, D.; Turki, M. M.; Arenillas, I.; Arz, J. A.; Molina, E.

    2009-04-01

    At the Bidart section, the extinction rate at the K/Pg boundary reach about 95 % of the planktic foraminiferal species; whereas the Cretaceous survivors persisting along the Danian could be restricted to opportunist species as G. cretacea and G. cf. trifolia, and probably some generalist species of Hedbergella and Heterohelix. The Guembelitria cretacea species, present a biostratigraphical interest, and define the Guembelitria cretacea biozone of the lower Danian interval. This biozone is marked by the presence of Guembelitria cretacea, G. trifolia, Hedbergella holmdelensis, H. monmouthensis, Heterohelix punctulata, H. glabrans, H. labellosa, H. planata, H. pulchra, H. globulosa, and H. navarroensis. The ecological opportunist or disaster species Guembelitria cretacea (>63 µm) is present in very low frequencies (<2.5%) in late Maastrichtian faunal assemblages of normal open marine environments in the Bidart section but more abundant at the lower Danian Gt. Cretacea biozone. During this early Danian biozone (Gt. cretacea and Pv. eugubina zone), the relative abundance of Guembelitria increased. They reached about 40%. This high Guembelitria abundance compared with the frequencies of the other species at the lower Danian of Bidart section is marked-contrasts with the very high abundances (80%) generally found in the basal Danian throughout the Tethys (El Kef GSSP and Ellès sections in Tunisia). There are several possible explanations for this difference of abundance of the Guembelitria genera in the Bidart section: this section located at the Atlantic realm, represents a post-K/Pg environment with less biotic stress than observed throughout the Tethys realm. Consequently, the Guembelitria blooming at the lower Danian is related to two conditions: the post K/Pg environment stress conditions throughout the Tethys, the Atlantic or the Antarctic realm and the biozone thickness related to the sedimentation rate deposits. Therefore, these taxa were really survivors and

  14. Spectral determination of concentrations of functionally diverse pigments in increasingly complex arctic tundra canopies.

    PubMed

    Boelman, Natalie T; Magney, Troy S; Logan, Barry A; Griffin, Kevin L; Eitel, Jan U H; Greaves, Heather; Prager, Case M; Vierling, Lee A

    2016-09-01

    As the Arctic warms, tundra vegetation is becoming taller and more structurally complex, as tall deciduous shrubs become increasingly dominant. Emerging studies reveal that shrubs exhibit photosynthetic resource partitioning, akin to forests, that may need accounting for in the "big leaf" net ecosystem exchange models. We conducted a lab experiment on sun and shade leaves from S. pulchra shrubs to determine the influence of both constitutive (slowly changing bulk carotenoid and chlorophyll pools) and facultative (rapidly changing xanthophyll cycle) pigment pools on a suite of spectral vegetation indices, to devise a rapid means of estimating within canopy resource partitioning. We found that: (1) the PRI of dark-adapted shade leaves (PRIo) was double that of sun leaves, and that PRIo was sensitive to variation among sun and shade leaves in both xanthophyll cycle pool size (V + A + Z) (r (2) = 0.59) and Chla/b (r (2) = 0.64); (2) A corrected PRI (difference between dark and illuminated leaves, ΔPRI) was more sensitive to variation among sun and shade leaves in changes to the epoxidation state of their xanthophyll cycle pigments (dEPS) (r (2) = 0.78, RMSE = 0.007) compared to the uncorrected PRI of illuminated leaves (PRI) (r (2) = 0.34, RMSE = 0.02); and (3) the SR680 index was correlated with each of (V + A + Z), lutein, bulk carotenoids, (V + A + Z)/(Chla + b), and Chla/b (r (2) range = 0.52-0.69). We suggest that ΔPRI be employed as a proxy for facultative pigment dynamics, and the SR680 for the estimation of constitutive pigment pools. We contribute the first Arctic-specific information on disentangling PRI-pigment relationships, and offer insight into how spectral indices can assess resource partitioning within shrub tundra canopies. PMID:27193900

  15. Assessing seedbank recruitment windows of opportunity in thaw slump thermokarsts

    NASA Astrophysics Data System (ADS)

    Huebner, D. C.; Bret-Harte, M. S.

    2013-12-01

    explained by lower seedbank quality but higher recruitment in younger lobes due to greater viable seed input and turnover, particularly of short-lived seeds such as willow, whereas older lobes and undisturbed tundra may have larger seedbanks whose recruitment of new individuals may be limited under natural conditions. Age cohort comparisons between willow species (Salix pulchra or S. glauca), as expected, found over 80% of individuals sampled at the young lobe between 3-4 y.a., while outside showed more variable distribution across six cohorts spanning five to 35 y.a. For both birch and willow, there was more cohort variability in the older lobe than outside, suggesting recruitment outcomes could have site-species interactions.

  16. Potential and limitations of Sr/Ca ratios in coccolith carbonate: new perspectives from cultures and monospecific samples from sediments.

    PubMed

    Stoll, Heather M; Ziveri, Patricia; Geisen, Markus; Probert, Ian; Young, Jeremy R

    2002-04-15

    The Sr/Ca ratio of coccoliths was recently proposed as a potential indicator of past growth rates of coccolithophorids, marine algae, which play key roles in both the global carbonate and carbon cycles. We synthesize calibrations of this proxy through laboratory culture studies and analysis of monospecific coccolith assemblages from surface sediments. Cultures of coccolithophorids Helicosphaera carteri, Syracosphaera pulchra and Algirospira robusta confirm a 1-2% increase in Sr/Ca per degrees C previously identified in Emiliania huxleyi and Gephyrocapsa oceanica. This effect is not due merely to increases in growth rate with temperature and must be considered in palaeoceanographic studies. In light-limited cultures of E. huxleyi, Calcidiscus leptoporus and G. oceanica at constant temperature, coccolith Sr/Ca ratios vary by 10% across the range of possible growth and calcification rates for a given species. Among different species under similar culture conditions, Sr/Ca ratios vary by 30%. Although the highest ratios are in the cells with highest calcification and organic carbon fixation rates, at lower rates there is much scatter, indicating that different mechanisms control interspecific and intraspecific coccolith Sr/Ca variations. In field studies in the Equatorial Pacific and Somalia coastal region, coccolith Sr/Ca correlates with upwelling intensity and productivity. A more dynamic response is observed in larger coccoliths like C. leptoporus (23-55% variation in Sr/Ca) than in smaller coccoliths of G. oceanica or Florisphaera profunda (6-15% variation in Sr/Ca). This response suggests that, despite temperature effects, coccolith Sr/Ca has potential as an indicator of coccolithophorid productivity. If the variable Sr/Ca response of different species accurately reflects their variable productivity response to upwelling (and not different slopes of Sr/Ca with productivity), coccolith Sr/Ca could provide useful data on past changes in coccolith ecology. The

  17. Seasonal greening of an Arctic ecosystem in response to early snowmelt and climate warming: do plant community responses differ from species responses?

    NASA Astrophysics Data System (ADS)

    Steltzer, H.; Weintraub, M. N.; Sullivan, P.; Wallenstein, M. D.; Schimel, J.; Darrouzet-Nardi, A.; Shory, R.; Livensperger, C.; Melle, C.; Segal, A. D.; Daly, K.; Tsosie, T.

    2011-12-01

    In the Arctic and around the world, earlier plant growth and a longer growing season are indications that warmer temperatures or other global changes are changing the seasonality of the Earth's ecosystems. These changes in plant life histories have multi-trophic level consequences that affect food webs and biogeochemical cycles. Both the response of the plant community and of individual species can affect food and habitat resources for animals or nutrient resources for microbes. Our aim was to determine if the response of an Arctic plant community differs from individual species responses to climate change. For two years in an early snowmelt and climate warming experiment in moist acidic tussock tundra, we observed the seasonal greening of the ecosystem through near-surface measurements of surface greenness and through direct observations of the timing of plant life history events for five to eight common species that differ in growth form. In 2010 when snowmelt was accelerated by 4 days, earlier snowmelt alone or in combination with climate warming extended the life history of the dominant graminoids (E. vaginatum and C. bigelowii) and willow (S. pulchra) by 3 to 4 days. For these species, new leaf production began earlier, while the timing of senescence was similar to the controls. The effect of earlier snowmelt on the life histories of birch (B. nana) and cranberry (V. vitis-idaea) was less, but warming alone tended to increase life history duration. Warming led to earlier leaf expansion for birch and delayed senescence for cranberry. We found that the onset of greening for the plant community began four days earlier, due to the earlier loss of snow cover, and that warming accelerated the rate of greening. Peak season ended 4 days earlier in response to earlier snowmelt and climate warming, due to earlier senescence by birch. In 2011, our manipulation of the snowpack by increasing energy absorption accelerated snowmelt by 15 days and control plots were snowfree

  18. Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans

    PubMed Central

    Estrada, Marta; Delgado, Maximino; Blasco, Dolors; Latasa, Mikel; Cabello, Ana María; Benítez-Barrios, Verónica; Fraile-Nuez, Eugenio; Mozetič, Patricija; Vidal, Montserrat

    2016-01-01

    We examine the large-scale distribution patterns of the nano- and microphytoplankton collected from 145 oceanic stations, at 3 m depth, the 20% light level and the depth of the subsurface chlorophyll maximum, during the Malaspina-2010 Expedition (December 2010-July 2011), which covered 15 biogeographical provinces across the Atlantic, Indian and Pacific oceans, between 35°N and 40°S. In general, the water column was stratified, the surface layers were nutrient-poor and the nano- and microplankton (hereafter phytoplankton, for simplicity, although it included also heterotrophic protists) community was dominated by dinoflagellates, other flagellates and coccolithophores, while the contribution of diatoms was only important in zones with shallow nutriclines such as the equatorial upwelling regions. We applied a principal component analysis to the correlation matrix among the abundances (after logarithmic transform) of the 76 most frequent taxa to synthesize the information contained in the phytoplankton data set. The main trends of variability identified consisted of: 1) A contrast between the community composition of the upper and the lower parts of the euphotic zone, expressed respectively by positive or negative scores of the first principal component, which was positively correlated with taxa such as the dinoflagellates Oxytoxum minutum and Scrippsiella spp., and the coccolithophores Discosphaera tubifera and Syracosphaera pulchra (HOL and HET), and negatively correlated with taxa like Ophiaster hydroideus (coccolithophore) and several diatoms, 2) a general abundance gradient between phytoplankton-rich regions with high abundances of dinoflagellate, coccolithophore and ciliate taxa, and phytoplankton-poor regions (second principal component), 3) differences in dominant phytoplankton and ciliate taxa among the Atlantic, the Indian and the Pacific oceans (third principal component) and 4) the occurrence of a diatom-dominated assemblage (the fourth principal

  19. Temporal and spatial variability in export production in the SE Pacific Ocean: evidence from siliceous plankton fluxes and surface sediment assemblages

    NASA Astrophysics Data System (ADS)

    Romero, Oscar E.; Hebbeln, Dierk; Wefer, Gerold

    2001-12-01

    Flux of siliceous plankton and taxonomic composition of diatom and silicoflagellate assemblages were determined from sediment trap samples collected in coastal upwelling-influenced waters off northern Chile (30°S, CH site) under "normal" or non-El Niño (1993-94) and El Niño conditions (1997-98). In addition, concentration of biogenic opal and siliceous plankton, and diatom and silicoflagellate assemblages preserved in surface sediments are provided for a wide area between 27° and 43°S off Chile. Regardless of the year, winter upwelling determines the maximum production pattern of siliceous microorganisms, with diatoms numerically dominating the biogenic opal flux. During the El Niño year the export is markedly lower: on an annual basis, total mass flux diminished by 60%, and diatom and silicoflagellate export by 75%. Major components of the diatom flora maintain much of their regular seasonal cycle of flux maxima and minima during both sampling periods. Neritic resting spores (RS) of Chaetoceros dominate the diatom flux, mirroring the influence of coastal-upwelled waters at the CH trap site. Occurrence of pelagic diatoms species Fragilariopsis doliolus, members of the Rhizosoleniaceae, Azpeitia spp. and Nitzschia interruptestriata, secondary components of the assemblage, reflects the intermingling of warmer waters of the Subtropical Gyre. Dictyocha messanensis dominates the silicoflagellate association almost year-around, but Distephanus pulchra delivers ca. 60% of its annual production in less than three weeks during the winter peak. The siliceous thanatocoenosis is largely dominated by diatoms, whose assemblage shows significant qualitative and quantitative variations from north to south. Between 27° and 35°S, the dominance of RS Chaetoceros, Thalassionema nitzschioides var. nitzschioides and Skeletonema costatum reflects strong export production associated with occurrence of coastal upwelling. Both highest biogenic opal content and diatom concentration

  20. Coccolithophores in the upwelling waters of Portugal: Four years of weekly distribution in Lisbon bay

    NASA Astrophysics Data System (ADS)

    Silva, A.; Palma, S.; Moita, M. T.

    2008-10-01

    Gephyrocapsa species can be used as proxies of surface productivity waters during spring and summer while Coccolithus pelagicus indicates the presence of upwelling fronts. Calcidiscus leptoporus is a tracer of the convergence of subtropical oceanic waters onto the shelf, during winter while Coronosphaera mediterranea, Syracosphaera pulchra, Helicosphaera carteri and Rhabdosphaera clavigera revealed the presence of those waters during the short period that characterized the transition from upwelling to downwelling seasons.

  1. Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans.

    PubMed

    Estrada, Marta; Delgado, Maximino; Blasco, Dolors; Latasa, Mikel; Cabello, Ana María; Benítez-Barrios, Verónica; Fraile-Nuez, Eugenio; Mozetič, Patricija; Vidal, Montserrat

    2016-01-01

    We examine the large-scale distribution patterns of the nano- and microphytoplankton collected from 145 oceanic stations, at 3 m depth, the 20% light level and the depth of the subsurface chlorophyll maximum, during the Malaspina-2010 Expedition (December 2010-July 2011), which covered 15 biogeographical provinces across the Atlantic, Indian and Pacific oceans, between 35°N and 40°S. In general, the water column was stratified, the surface layers were nutrient-poor and the nano- and microplankton (hereafter phytoplankton, for simplicity, although it included also heterotrophic protists) community was dominated by dinoflagellates, other flagellates and coccolithophores, while the contribution of diatoms was only important in zones with shallow nutriclines such as the equatorial upwelling regions. We applied a principal component analysis to the correlation matrix among the abundances (after logarithmic transform) of the 76 most frequent taxa to synthesize the information contained in the phytoplankton data set. The main trends of variability identified consisted of: 1) A contrast between the community composition of the upper and the lower parts of the euphotic zone, expressed respectively by positive or negative scores of the first principal component, which was positively correlated with taxa such as the dinoflagellates Oxytoxum minutum and Scrippsiella spp., and the coccolithophores Discosphaera tubifera and Syracosphaera pulchra (HOL and HET), and negatively correlated with taxa like Ophiaster hydroideus (coccolithophore) and several diatoms, 2) a general abundance gradient between phytoplankton-rich regions with high abundances of dinoflagellate, coccolithophore and ciliate taxa, and phytoplankton-poor regions (second principal component), 3) differences in dominant phytoplankton and ciliate taxa among the Atlantic, the Indian and the Pacific oceans (third principal component) and 4) the occurrence of a diatom-dominated assemblage (the fourth principal

  2. Spectral determination of concentrations of functionally diverse pigments in increasingly complex arctic tundra canopies.

    PubMed

    Boelman, Natalie T; Magney, Troy S; Logan, Barry A; Griffin, Kevin L; Eitel, Jan U H; Greaves, Heather; Prager, Case M; Vierling, Lee A

    2016-09-01

    As the Arctic warms, tundra vegetation is becoming taller and more structurally complex, as tall deciduous shrubs become increasingly dominant. Emerging studies reveal that shrubs exhibit photosynthetic resource partitioning, akin to forests, that may need accounting for in the "big leaf" net ecosystem exchange models. We conducted a lab experiment on sun and shade leaves from S. pulchra shrubs to determine the influence of both constitutive (slowly changing bulk carotenoid and chlorophyll pools) and facultative (rapidly changing xanthophyll cycle) pigment pools on a suite of spectral vegetation indices, to devise a rapid means of estimating within canopy resource partitioning. We found that: (1) the PRI of dark-adapted shade leaves (PRIo) was double that of sun leaves, and that PRIo was sensitive to variation among sun and shade leaves in both xanthophyll cycle pool size (V + A + Z) (r (2) = 0.59) and Chla/b (r (2) = 0.64); (2) A corrected PRI (difference between dark and illuminated leaves, ΔPRI) was more sensitive to variation among sun and shade leaves in changes to the epoxidation state of their xanthophyll cycle pigments (dEPS) (r (2) = 0.78, RMSE = 0.007) compared to the uncorrected PRI of illuminated leaves (PRI) (r (2) = 0.34, RMSE = 0.02); and (3) the SR680 index was correlated with each of (V + A + Z), lutein, bulk carotenoids, (V + A + Z)/(Chla + b), and Chla/b (r (2) range = 0.52-0.69). We suggest that ΔPRI be employed as a proxy for facultative pigment dynamics, and the SR680 for the estimation of constitutive pigment pools. We contribute the first Arctic-specific information on disentangling PRI-pigment relationships, and offer insight into how spectral indices can assess resource partitioning within shrub tundra canopies.

  3. Environmental Limits of Tall Shrubs in Alaska's Arctic National Parks.

    PubMed

    Swanson, David K

    2015-01-01

    We sampled shrub canopy volume (height times area) and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss) on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this information to predict the location of future shrub expansion. The study area covers over 80,000 km2 and has mostly tundra vegetation. Large canopy volumes were uncommon, with volumes over 0.5 m3/m2 present on just 8% of plots. Shrub canopy volumes were highest where mean July temperatures were above 10.5°C and on weakly acid to neutral soils (pH of 6 to 7) with deep summer thaw (>80 cm) and good drainage. On many sites, flooding helped maintain favorable soil conditions for shrub growth. Canopy volumes were highest where the typical snow loss date was near 20 May; these represent sites that are neither strongly wind-scoured in the winter nor late to melt from deep snowdrifts. Individual species varied widely in the canopy volumes they attained and their response to the environmental factors. Betula sp. shrubs were the most common and quite tolerant of soil acidity, cold July temperatures, and shallow thaw depths, but they did not form high-volume canopies under these conditions. Alnus viridis formed the largest canopies and was tolerant of soil acidity down to about pH 5, but required more summer warmth (over 12°C) than the other species. The Salix species varied widely from S. pulchra, tolerant of wet and moderately acid soils, to S. alaxensis, requiring well-drained soils with near neutral pH. Nearly half of the land area in ARCN has mean July temperatures of 10.5 to 12.5°C, where 2°C of warming would bring temperatures into the range needed for all of the potential tall shrub species to form large canopies. However, limitations in the other environmental factors would probably prevent the formation of large shrub canopies

  4. Environmental Limits of Tall Shrubs in Alaska’s Arctic National Parks

    PubMed Central

    Swanson, David K.

    2015-01-01

    We sampled shrub canopy volume (height times area) and environmental factors (soil wetness, soil depth of thaw, soil pH, mean July air temperature, and typical date of spring snow loss) on 471 plots across five National Park Service units in northern Alaska. Our goal was to determine the environments where tall shrubs thrive and use this information to predict the location of future shrub expansion. The study area covers over 80,000 km2 and has mostly tundra vegetation. Large canopy volumes were uncommon, with volumes over 0.5 m3/m2 present on just 8% of plots. Shrub canopy volumes were highest where mean July temperatures were above 10.5°C and on weakly acid to neutral soils (pH of 6 to 7) with deep summer thaw (>80 cm) and good drainage. On many sites, flooding helped maintain favorable soil conditions for shrub growth. Canopy volumes were highest where the typical snow loss date was near 20 May; these represent sites that are neither strongly wind-scoured in the winter nor late to melt from deep snowdrifts. Individual species varied widely in the canopy volumes they attained and their response to the environmental factors. Betula sp. shrubs were the most common and quite tolerant of soil acidity, cold July temperatures, and shallow thaw depths, but they did not form high-volume canopies under these conditions. Alnus viridis formed the largest canopies and was tolerant of soil acidity down to about pH 5, but required more summer warmth (over 12°C) than the other species. The Salix species varied widely from S. pulchra, tolerant of wet and moderately acid soils, to S. alaxensis, requiring well-drained soils with near neutral pH. Nearly half of the land area in ARCN has mean July temperatures of 10.5 to 12.5°C, where 2°C of warming would bring temperatures into the range needed for all of the potential tall shrub species to form large canopies. However, limitations in the other environmental factors would probably prevent the formation of large shrub canopies

  5. Rainfall, nitrogen deposition and fire disturbance impacts in a California coastal grassland

    NASA Astrophysics Data System (ADS)

    Potts, D. L.; Winston, G.; Rocha, A.; Suding, K. N.; Goulden, M. L.

    2007-12-01

    In semi-arid ecosystems, shifts in soil moisture availability may mediate the response of individual species, communities and ecosystems to disturbance or changes in nutrient availability. How these interactive effects scale through different levels of ecological organization is poorly understood but essential for robust predictions of the effects of environmental change. In 2007, a year of record low rainfall, we conducted a prescribed fire in a coastal grassland in Orange County California. Within both burned and unburned portions of the grassland, we increased and decreased rainfall (with water addition and rainout shelters, respectively) and increased nitrogen (with N fertilization) in all possible treatment combinations. We asked the question: can physiological responses of the dominant species predict changes in ecosystem function to these interactive environmental manipulations? The native perennial bunchgrass, Nassella pulchra had higher rates of CO 2 uptake and stomatal conductance than the nonnative annual grass, Bromus diandrus across rainfall treatments in both the burned and unburned areas. Both species maintained relatively constant physiological responses regardless of environmental manipulation. Thus, based on these resilient individual-level responses, we predicted that ecosystem-responses would be relatively resilient to the environmental changes. Consistent with this prediction, burning and nitrogen did not strongly affect ecosystem function. However, we detected relatively large responses at the ecosystem level in response to rainfall manipulations, and these effects were generally consistent across burning and N fertilization treatments. Ecosystem respiration, photosynthesis (GEE) and evapotranspiration (ET) declined in response to rainfall removal but did not respond to increases in rainfall. In contrast, the response of annual net primary productivity (ANPP) and a canopy spectral index (NDVI) was greatest in rainfall addition plots. NDVI was

  6. Climate change effects on vegetation in Northeastern Siberian tundra - How does shrub growth relate to local climate and what are potential effects of shrub expansion on permafrost thawing?

    NASA Astrophysics Data System (ADS)

    Blok, Daan; Schaepman-Strub, Gabriela; Heijmans, Monique; Sass-Klaassen, Ute; Bartholomeus, Harm; Knyazikhin, Yuri; Berendse, Frank

    2010-05-01

    The Siberian tundra is one of the key permafrost regions in the Arctic because of its large spatial extent and carbon-rich yedoma soils. Changes in permafrost thaw and concomitant carbon losses to the atmosphere can have large impacts on the global climate. Permafrost thaw is believed to strongly increase this century as a result of predicted increasing air temperature. At the same time, Arctic vegetation growth and composition is predicted to respond to future climate change. Deciduous shrubs are expected to benefit most from climate warming by increasing growth and expanding their range to higher latitudes. Evidence for recent increases in deciduous shrub cover in the Arctic region is limited thus far to small areas in Alaska. We examined if deciduous shrubs at our research site in the Indigirka lowlands, Northeastern Siberia, show a growth response to the main climate variables, temperature and precipitation. We constructed tree-ring width chronologies for two key Arctic deciduous shrub species, Betula nana and Salix pulchra, dating back roughly 60 years. The ring widths records are compared to summer-warmth index and summer-precipitation data from the closest climate station, approximately 30 km from our site in order to detect the climate factor that mainly determines shrub growth. On a larger scale, recent increases in Arctic productivity, measured as Arctic greenness (Normalized Difference Vegetation Index, NDVI), suggest that shrubs may have expanded during the 80ies and 90ies of the last century. Spectral reflectance data of varying vegetation composition measured at the tundra site were reduced to NDVI to link up with long-term NDVI data. We used a multiple regression analysis to estimate how variation in NDVI is explained by plant fractional cover of different plant functional types (graminoids, deciduous shrubs, evergreen shrubs, forbs, mosses and lichens). Deciduous shrub cover was the only significant explanatory parameter in the model after parameter

  7. Evaluating the Effectiveness of Native Grass Riparian Buffer Strips to Reduce Pesticide Runoff

    NASA Astrophysics Data System (ADS)

    Grossman, K.; Brown, D. L.

    2007-12-01

    Organophosphate pesticides such as diazinon have been a major source of non-point source water pollution in the Sacramento Valley watershed of central California. Diazinon is commonly listed as a pollutant for many tributaries of the Sacramento River on the US Clean Water Act section 303(d) list of impaired waterways. This pesticide is applied either aerially or as a foliar spray to nut and stone-fruit orchards during dormancy, which coincides with the rainy season in northern California. A study was conducted to determine if planting native grasses in the riparian zone was effective in reducing the amount of diazinon entering the surface water in streams flowing through these orchards. Native grasses have deeper root systems and were hypothesized to be more effective in sorbing diazinon and preventing its runoff than non-native grasses. In 2004, nine 20 foot by 20 foot riparian buffer plots were constructed along the banks of the South Fork of Walker Creek, west of the town of Orland in the Sacramento Valley. Three of the nine plots were maintained as bare ground, three were left with resident weeds including dense non-native grasses, and three were planted with native grasses, which included purple needlegrass (Nassella pulchra), creeping wildrye (Elymus triticoides), and deergrass (Muhlenbergia rigens). The experimental design simulated orchard runoff by applying mixtures of water and diazinon at observed field concentrations. The pesticide load was evenly applied across the top of each buffer plot at a rate consistent with local runoff rates in an average storm. Rainfall on the buffer plots was simulated with overhead sprinklers at a rate of 0.75 inches per hour, also an average storm for this area. Runoff was monitored at the downslope side of the plots with flumes funneled to large holding tanks. From these tanks, composite water samples were collected after runoff had ceased. The samples were analyzed for diazinon concentration, nitrates, and total suspended

  8. Influence of solar activity on the development of calcareous nannofossils from a Middle Holocene costal paleo-ria (SW Portugal)

    NASA Astrophysics Data System (ADS)

    Hernández, Armand; Cachão, Mário; Trigo, Ricardo M.; Conceição Freitas, M.

    2015-04-01

    A 27 m long core was recovered from a present day flat-floored small fluvial valley, tributary of the Mira River (SW Portugal) allowing to span almost the complete Holocene sedimentary sequence directly overlaying Paleozoic schists and greywackes. A high resolution study of its micropaleontological content (Alday et al. 2006) was performed and 5 sedimentary stages were established: i) a coccolith-barren lower fluvial stage; ii) a coccolith intermittent lower estuarine stage; iii) a coccolith rich marine (ria) stage; iv) a coccolith intermittent upper estuarine/lagoonal stage and v) a coccolith-barren upper fluvial stage. The usefulness of calcareous nannofossils as natural tracers of the marine sedimentation contributing with valuable information for environmental reconstructions has been thoroughly demonstrated. Here, we present a high-resolution paleoenvironmental reconstruction from the interpreted marine (ria) section of the core, between 8.8k and 4.8k cal yr BP using most abundant calcareous nannofossils. Factor Analysis retrieved two major factors from the coccolith assemblages. Factor 1 (24% var.) is related to oceanic affinity community (e.g. Gephyrocapsa muellerae, Syracosphaera pulchra and Umbilicosphaera sibogae) whereas Factor 2 (23% var.) is linked to coastal neritic taxa (e.g. Ascidian spicules, Gephyrocapsa oceanica, Coccolithus pelagicus braarudii, Heliscosphaera carteri and Braarudosphaera bigelowii). These scores showed the existence of two episodes (8.8k to 7.4k and 5.8k to 5.2k cal yr BP) of marine colonization inside the paleoecological succession of the Holocene paleo-ria (8.8k and 4.8k cal yr BP). In order to establish the relationship between the solar activity and calcareous nannofossils sedimentation, cyclicity on the studied time series was investigated by performing spectral analysis on Factor 1 (F1) and Factor 2 (F2) scores. F1 score periodogram discloses three significant periodicities (460, 350 and 236-yrs) whereas F2 score

  9. The Regional Geochemistry of Soils and Willow in a Metamorphic Bedrock Terrain, Seward Peninsula, Alaska, 2005, and Its Possible Relation to Moose

    USGS Publications Warehouse

    Gough, L.P.; Lamothe, P.J.; Sanzolone, R.F.; Drew, L.J.; Maier, J.A.K.

    2009-01-01

    In 2005 willow leaves (all variants of Salix pulchra) and A-, B-, and C-horizon soils were sampled at 10 sites along a transect near the Quarry prospect and 11 sites along a transect near the Big Hurrah mine for the purpose of defining the spatial variability of elements and the regional geochemistry of willow and soil over Paleozoic metamorphic rocks potentially high in cadmium (Cd). Willow, a favorite browse of moose (Alces alces), has been shown by various investigators to bioaccumulate Cd. Moose in this region show clinical signs of tooth wear and breakage and are declining in population for unknown reasons. A trace element imbalance in their diet has been proposed as a possible cause for these observations. Cadmium, in high enough concentrations, is one dietary trace element that potentially could produce such symptoms. We report both the summary statistics for elements in willow and soils and the results of an unbalanced, one-way, hierarchical analysis of variance (ANOVA) (general linear model, GLM), which was constructed to measure the geochemical variability in willow (and soil) at various distance scales across the Paleozoic geologic unit high in bioavailable Cd. All of the geochemical data are presented in the Appendices. The two locations are separated by approximately 80 kilometers (km); sites within a location are approximately 0.5 kilometers apart. Duplicate soil samples collected within a site were separated by 0.05 km or slightly less. Results of the GLM are element specific and range from having very little regional variability to having most of their variance at the top (greater than 80 km) level. For willow, a significant proportion of the total variance occurred at the 'between locations' level for ash yield, barium (Ba), Cd, calcium (Ca), cobalt (Co), nickel (Ni), and zinc (Zn). For soils, concentrations of elements in all three soil horizons were similar in that most of the variability in the geochemical data occurred at the 'between locations