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Search Results: 1 - 10 of 220877 matches for " Birgit C Schlick-Steiner "
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A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture
Munetoshi Maruyama, Florian M Steiner, Christian Stauffer, Toshiharu Akino, Ross H Crozier, Birgit C Schlick-Steiner
BMC Evolutionary Biology , 2008, DOI: 10.1186/1471-2148-8-237
Abstract: We recovered two well supported major lineages. One includes Acanthomyops, Austrolasius, Chthonolasius, and Lasius pallitarsis, which we confirm to represent a seventh subgenus, the other clade contains Dendrolasius, and Lasius sensu stricto. The subgenus Cautolasius, displaying neither social parasitism nor fungiculture, probably belongs to the second clade, but its phylogenetic position is not resolved at the cutoff values of node support we apply. Possible causes for previous problems with reconstructing the Lasius phylogeny include use of other reconstruction techniques, possibly more prone to instabilities in some instances, and the inclusion of phylogenetically distorting characters.By establishing an updated phylogenetic framework, our study provides the basis for a later formal taxonomic revision of subgenera and for studying the evolution of various ecologically and sociobiologically relevant traits of Lasius, although there is need for future studies to include nuclear genes and additional samples from the Nearctic. Both social parasitism and fungiculture evolved twice in Lasius, once in each major lineage, which opens up new opportunities for comparative analyses. The repeated evolution of social parasitism has been established for other groups of ants, though not for temporary social parasitism as found in Lasius. For fungiculture, the independent emergence twice in a monophyletic group marks a novel scenario in ants. We present alternative hypotheses for the evolution of both traits, with one of each involving loss of the trait. Though less likely for both traits than later evolution without reversal, we consider reversal as sufficiently plausible to merit independent testing.Ants of the Northern-hemispheric, temperate genus Lasius (Formicinae) are scientifically significant, in terms of relative abundance and ecological impact [1,2]. Because of the diversity of their signal and defense chemistry, Lasius ants are organisms widely used in chemical ecolog
The Evolution of Invasiveness in Garden Ants
Sylvia Cremer, Line V. Ugelvig, Falko P. Drijfhout, Birgit C. Schlick-Steiner, Florian M. Steiner, Bernhard Seifert, David P. Hughes, Andreas Schulz, Klaus S. Petersen, Heino Konrad, Christian Stauffer, Kadri Kiran, Xavier Espadaler, Patrizia d'Ettorre, Nihat Akta?, J?rgen Eilenberg, Graeme R. Jones, David R. Nash, Jes S. Pedersen, Jacobus J. Boomsma
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003838
Abstract: It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects.
Population Fluctuation and Vertical Distribution of the Soybean Looper (Chrysodeixis includes) in Soybean Culture  [PDF]
Daniele Zulin, Crébio J. ávila, Eunice C. Schlick-Souza
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.97113
Abstract: The objective of this work was to study the population fluctuation and the vertical distribution of the Chrysodeixis includes (Walker) (Lepidoptera: Noctuidae) in the leaf canopy of soybeans. The experiments were conducted under field conditions in the experimental area of the Embrapa Agropecuária Oeste during the 2014/2015 harvest. Adult monitoring was performed using Delta-type traps, baited with the pest sexual pheromone. The eggs were collected in the soybean plants and the caterpillars monitored through the beat cloth. The population peaks of C. includes occurred in the reproductive period of the soybean plants, although the adults were also found in the season soybean. Although there was no significant relationship between the trapped adults and the immature forms of
Direct and Indirect Effect of Bt Cotton and No Bt Cotton on the Development and Reproduction of the Predator Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae)  [PDF]
Alexa G. Santana, Crébio J. áVila, Harley N. de Oliveira, Patrícia P. Bellon, Eunice C. Schlick-Souza
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.86098
Abstract: This paper aimed to evaluate the direct and indirect effects of Bt cotton and no Bt cotton on the development and reproduction of the predator Podisus nigrispinus (Dallas). The experiments related to the direct and indirect effects on immature and adult stages of the predator were conducted, respectively, in greenhouse and laboratory of the Embrapa Agropecuária Oeste in Dourados, Mato Grosso do Sul State, Brazil. To evaluate the indirect effects of Bt cotton and non-Bt, larvae of Spodoptera frugiperda (Smith) were fed with these plants and later offered to the predator. To evaluate the direct effect of the Bt cotton and non-Bt, the predator P. nigrispinus was kept in contact with these
Resistance of squash cultivars to Aphis gossypii
Baldin, Edson LL;Marchi, Lia S;Schlick, Eunice C;
Horticultura Brasileira , 2009, DOI: 10.1590/S0102-05362009000300020
Abstract: the cucurbitaceae plants are damaged by attack of a wide spectrum of insects and microorganisms. among the sucker insects causing damages on squash cucurbita pepo (l.), the aphid aphis gossypii (glover) (hemiptera: aphididae) is pointed as one of the most important, once their nymphs and adults suck the sap of the leaves continuously, besides being potential vector of virus. the present research evaluated different cultivars, aiming to identify the resistance against this aphid. the cultivars novita, sandy, caserta cac melhorada, novita plus, samira, af-2858 and caserta ts were used in laboratory assays (t= 25±2oc; rh= 70±10% and fotophase= 12 h). in the immature phase the duration of nymphal instars was evaluated, the total duration and their viability, confining individuals on leaf disks from cultivars. in the adult phase the duration of reproductive period, the fecundity and the biological cycle were observed. the cultivar 'sandy' expressed high level of antibiosis and feeding non-preference against a. gossypii, increasing the nymphal stage and causing mortality near to 70%. besides, this cultivar reduced the production of nymphs and the longevity of the insects. the 'novita plus' cultivar also induced significant nymphal mortality, however in lower levels than those verified in 'sandy', indicating a moderate resistance.
Hair Anomalies in a 6-Year-Old Girl  [PDF]
M. Wruhs, C. Bergthaler, F. Breier, A. Steiner, P. Sator
Case Reports in Clinical Medicine (CRCM) , 2016, DOI: 10.4236/crcm.2016.53015
Abstract: Monilehtrix is a rare inherited hair shaft disorder with considerable variations in age of onset severity and course. We present a 6-year-old girl with monilethrix and discuss different aspects of the disease and its treatment.
A sketch of Arnfried Antonius (1934 - 2010)
Sascha C.C Steiner
Revista de Biología Tropical , 2012,
Synthetic Biology of Proteins: Tuning GFPs Folding and Stability with Fluoroproline
Thomas Steiner, Petra Hess, Jae Hyun Bae, Birgit Wiltschi, Luis Moroder, Nediljko Budisa
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001680
Abstract: Background Proline residues affect protein folding and stability via cis/trans isomerization of peptide bonds and by the Cγ-exo or -endo puckering of their pyrrolidine rings. Peptide bond conformation as well as puckering propensity can be manipulated by proper choice of ring substituents, e.g. Cγ-fluorination. Synthetic chemistry has routinely exploited ring-substituted proline analogs in order to change, modulate or control folding and stability of peptides. Methodology/Principal Findings In order to transmit this synthetic strategy to complex proteins, the ten proline residues of enhanced green fluorescent protein (EGFP) were globally replaced by (4R)- and (4S)-fluoroprolines (FPro). By this approach, we expected to affect the cis/trans peptidyl-proline bond isomerization and pyrrolidine ring puckering, which are responsible for the slow folding of this protein. Expression of both protein variants occurred at levels comparable to the parent protein, but the (4R)-FPro-EGFP resulted in irreversibly unfolded inclusion bodies, whereas the (4S)-FPro-EGFP led to a soluble fluorescent protein. Upon thermal denaturation, refolding of this variant occurs at significantly higher rates than the parent EGFP. Comparative inspection of the X-ray structures of EGFP and (4S)-FPro-EGFP allowed to correlate the significantly improved refolding with the Cγ-endo puckering of the pyrrolidine rings, which is favored by 4S-fluorination, and to lesser extents with the cis/trans isomerization of the prolines. Conclusions/Significance We discovered that the folding rates and stability of GFP are affected to a lesser extent by cis/trans isomerization of the proline bonds than by the puckering of pyrrolidine rings. In the Cγ-endo conformation the fluorine atoms are positioned in the structural context of the GFP such that a network of favorable local interactions is established. From these results the combined use of synthetic amino acids along with detailed structural knowledge and existing protein engineering methods can be envisioned as a promising strategy for the design of complex tailor-made proteins and even cellular structures of superior properties compared to the native forms.
Gait changes precede overt arthritis and strongly correlate with symptoms and histopathological events in pristane-induced arthritis
Markus H Hoffmann, Rudolf Hopf, Birgit Niederreiter, Heinz Redl, Josef S Smolen, Günter Steiner
Arthritis Research & Therapy , 2010, DOI: 10.1186/ar2950
Abstract: Arthritis was induced in DA.rats by injection of 150 μl 2,6,10,4-tetramethyl-pentadecane (pristane) at the base of the tail and changes in locomotor behaviour of the affected paws were monitored using the CatWalk quantitative gait analysis system. The pathologic events occurring in the joints of pristane-injected animals were studied before onset, at onset, and during acute phase of arthritis by histological methods.Gait analysis revealed that changes in locomotion such as reduced paw print areas and stance phase time are already apparent before the onset of clinically discernible arthritis symptoms (erythema, paw swelling) and correlate with PIA scores. In agreement with these findings, inflammatory tenosynovitis could be observed by histology already before the onset of erythema and swelling of the respective paws. In the most heavily affected rats also irregularities in step sequence patterns occurred A kinetic analysis of clinical and histological findings demonstrated that gait changes precede the pathological changes occurring during the acute phase of pristane-induced arthritis.Gait analysis allows for pinpointing the initial inflammatory changes in experimental arthritis models such as pristane-induced arthritis. Analysis of early clinically relevant symptoms in arthritis models may facilitate the search for novel therapeutics to interfere with pain, inflammation and joint destruction in patients suffering from inflammatory arthritis.Arthritis is a clinical entity characterized by joint swelling, stiffness and spontaneous or motion-related pain. Impairment of physical function, that is, disability, is the major complication of arthritis and the degree of its reversibility depends on both our potential to interfere with the active disease process as well as with joint damage, given that the latter is currently not reversible [1].Our current knowledge on the pathogenesis of chronic inflammatory joint diseases such as rheumatoid arthritis (RA) is still limited.
A recent increase in the abundance of the echinoid Diadema antillarum in Dominica (Lesser Antilles): 2001-2005
Steiner,S. C. C; Williams,S. M;
Revista de Biología Tropical , 2006,
Abstract: diadema antillarum populations at many caribbean locations have failed to recover from the pathogen-induced mortality events of the 1980s. it has become clear that the massive decline of this herbivorous urchin and the wide-spread absence of a population recovery lead to numerous long-term ecological consequences and reef degradation. while few quantitative studies on pre-mortality exist, great effort has been put forth to monitor remaining populations and their recovery. however, the patchy distribution of d. antillarum coupled with paucity of long-term studies based on the same methods applied at the same locations undermines the value of local as well as regional comparisons. in dominica, ongoing quantitative assessments of d. antillarum began in 2001. surveys of d. antillarum abundance are being carried out in 4-month intervals at six 100 m2 sites; spread over 38 km along the west coast. the density of d. antillarum has differed significantly between sites, ranging from 0.81(sd= 0.04) to 3.13 m-2 (sd= 2.10), and increased by 61.11% during the first five years of this study. seasonal fluctuations, possibly related to spawning aggregations, are also evident. the current abundance of d. antillarum on dominican reefs contrasts that of caribbean locations with recorded incidents of mass mortality events, and in some cases resembles pre-mortality densities from the early 1970s. prior to this study, no systematic quantitative assessments of d. antillarum were carried out in dominica. it is thus unclear in what way dominica?s d. antillarum were affected by the mass mortality events observed elsewhere in the 1980s. the increase in d. antillarum density so far observed may thus be the recovery from a pathogen-induced disturbance or from hurricane lenny in november 1999. locally, d. antillarum is important grazer on dominican?s reefs, where over-fishing has drastically reduced the number of herbivorous fishes. on a regional scale, the island?s d. antillarum may represent a
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