828 research outputs found
First description of algal mutualistic endosymbiosis in a black coral (Anthozoa: Antipatharia)
No full textThe class Anthozoa is the largest metazoan group forming mutualistic symbioses with microalgae. These algal symbionts (most commonly dinoflagellates of the genus
) are distributed across most anthozoan orders. Records of algal cells in antipatharian (black coral) tissues have been reported, but no detailed descriptions of a mutualistic endosymbiosis exist. Here we report on zooxanthellate specimens of an unidentified black coral species within the genus
that were collected from reef slopes at depths of 15 to 38 m in the Indonesian Archipelago. Symbionts were abundant (~10⁷ symbionts cm
) and ultrastructural analysis revealed the presence of a distinct symbiosome surrounding the algae, as well as algal reproduction inside the gastrodermal layer. Molecular analysis revealed the algae to be closely related to the symbionts (
clade G) of clionid sponges. There was also evidence for additional symbionts in clade C at low abundance. Taken together, these findings (high abundance, taxonomic identity, presence of symbiosome,
reproduction, and depth distribution) strongly suggest that these algae are functioning as mutualists. This study confirms and describes the symbiosis between
and a black coral species of the genus
, supports the pervasiveness of mutualisms among anthozoan taxa, and highlights the diversity and flexibility of these symbiotic associations in a poorly studied group
Phylogenetic Relationships in the Gorgonian Family Plexauridae (Anthozoa: Octocorallia: Holaxonia) Based on Two Mitochondrial Genes: Evidence for Multiple Lineages
No full textHolaxonian octocorals are diverse and abundant on many marine hard substrates and, within this group, members of the Plexauridae are an important component of tropical reef assemblages. In the most recent morphological revision of octocorals, Bayer (1981) included the Paramuriceidae (as Stenogorgiinae) within the plexaurids based on a lack of distinguishing characters. As a result, the Plexauridae now comprises 31 genera and occurs throughout the tropics as well as at higher latitudes to depths of at least 900 m. To begin to understand historical relationships within this now large and diverse assemblage, and to test the monophyly of the family and some of its component genera, DNA sequences of two mitochondrial loci (msh1 and ND2, ~1212 bp) from 40 species in 21 genera from deep and shallow waters in the tropical western Atlantic, West and East Pacific (plus 5 taxa in the closely related Gorgoniidae and two outgroups) were analyzed. Results recover three strongly supported clades that correspond roughly to the Plexauridae, Paramuriceidae and Gorgoniidae, though their mutual relationships remain unclear. Representatives of several genera appear to be scattered among the 3 families ; e.g., Hypnogorgia sp. (Paramuriceidae) falls within a clade consisting of both Pacific and Atlantic Muricea spp. (Plexauridae), while Swiftia sp., Scleracis sp. and an Atlantic Thesea sp. (all Paramuriceidae) group with the gorgoniids. Some Atlantic and Pacific species of several plexaurid and paramuriceid genera were monophyletic (Muricea spp., Bebryce spp.), while others were not (Echinomuricea spp., Thesea spp., Villogorgia spp.). These molecular results indicate that current octocoral taxonomy needs revision
Six Characters In Search Of An Author
No full textProgram from the Little Theatre of Dallas' 1932 production of 'Six Characters In Search Of An Author,' written by Luigi Pirandello and directed by Charles Meredith. Setting arrangement by Alexandre Hogue. Cover art by Leon Dacus. Exhibitions by Olin Herman Travis and Kathryne Hail Travis
Biodiversity estimates and ecological interpretations of meiofaunal communities are biased by the taxonomic approach
No full textAccurate assessments of biodiversity are crucial to advising ecosystem-monitoring programs
and understanding ecosystem function. Nevertheless, a standard operating procedure to assess
biodiversity accurately and consistently has not been established. This is especially true for
meiofauna, a diverse community (>20 phyla) of small benthic invertebrates that have fundamental ecological roles. Recent studies show that metabarcoding is a cost-effective and timeeffective method to estimate meiofauna biodiversity, in contrast to morphological-based taxonomy. Here, we compare biodiversity assessments of a diverse meiofaunal community derived by applying multiple taxonomic methods based on comparative morphology, molecular phylogenetic analysis, DNA barcoding of individual specimens, and metabarcoding of environmental DNA. We show that biodiversity estimates are strongly biased across taxonomic methods and phyla. Such biases affect understanding of community structures and ecological interpretations. This study supports the urgency of improving aspects of environmental high-throughput sequencing and the value of taxonomists in correctly understanding biodiversity estimates
Molecular and Morphological Species Boundaries in the Gorgonian Octocoral Genus Pterogorgia (Octocorallia: Gorgoniidae).
No full textMost gorgonian octocoral species are described using diagnostic characteristics of their sclerites (microscopic skeletal components). Species in the genus Pterogorgia, however, are separated primarily by differences in their calyx and branch morphology. Specimens of a morphologically unusual Pterogorgia collected from Saba Bank in the NE Caribbean Sea were found with calyx morphology similar to P. citrina and branch morphology similar to P. guadalupensis. In order to test morphological species boundaries, and the validity of calyx and branch morphology as systematic characters, a phylogenetic analysis was undertaken utilizing partial gene fragments of three mitochondrial (mtMutS, cytochrome b, and igr4; 726bp total) and two nuclear (ITS2, 166bp; and SRP54 intron, 143bp) loci. The datasets for nuclear and mitochondrial loci contained few phylogenetically informative sites, and tree topologies did not resolve any of the morphological species as monophyletic groups. Instead, the mitochondrial loci and SRP54 each recovered two clades but were slightly incongruent, with a few individuals of P. guadalupensis represented in both clades with SRP54. A concatenated dataset of these loci grouped all P. anceps and P. guadalupensis in a clade, and P. citrina and the Pterogorgia sp. from Saba Bank in a sister clade, but with minimal variation/resolution within each clade. However, in common with other octocoral taxa, the limited genetic variation may not have been able to resolve whether branch variation represents intraspecific variation or separate species. Therefore, these results suggest that there are at least two phylogenetic lineages of Pterogorgia at the species level, and the atypical Pterogorgia sp. may represent an unusual morphotype of P. citrina, possibly endemic to Saba Bank. Branch morphology does not appear to be a reliable morphological character to differentiate Pterogorgia species (e.g., branches "flat" or "3-4 edges" in P. guadalupensis and P. anceps, respectively), and a re-evaluation of species-level characters (e.g., sclerites) is needed
Zoonotic potential of Giardia duodenalis and Cryptosporidium spp. and prevalence of intestinal parasites in young dogs from different populations on Prince Edward Island, Canada
No full textThe prevalence of Giardia duodenalis, Cryptosporidium spp. and other intestinal parasites was determined in dogs <1 year old from Prince Edward Island, Canada. Fecal samples were collected from the local animal shelter (n=62), private veterinary clinics (n=78) and a pet store (n=69). Intestinal parasites isolated included G. duodenalis, Cryptosporidium spp., Toxocara canis, Isospora spp. and Uncinaria stenocephala. To estimate the zoonotic risk associated with these infections, genotypes of G. duodenalis and Cryptosporidium spp. were determined using 16S rRNA and Hsp70 gene sequencing, respectively. Dogs from the pet store had the highest prevalence of intestinal parasites (78%, 95% CI: 68-88%), followed by the private veterinary clinics (49%, 95% CI: 37-60%), and the local animal shelter (34%, 95% CI: 22-46%). The majority G. duodenalis belonged to host-adapted assemblages D (47%, 95% CI: 31-64%) and C (26%, 95% CI: 13-43%), respectively. Zoonotic assemblages A and B were isolated alone or in mixed infections from 16% (95% CI: 6-31%) of G. duodenalis-positive dogs. All Cryptosporidium spp. were the host-adapted C. canis. While host-adapted, non-zoonotic G. duodenalis genotypes were more common, the presence of G. duodenalis assemblages A and B, T. canis, and U. stenocephala suggests that these dogs may present a zoonotic risk. The zoonotic risk from Cryptosporidium-infected dogs was minimal.Fabienne D. Uehlinger, Spencer J. Greenwood, J. Trenton McClure, Gary Conboy, Ryan O’Handley, Herman W. Barkem
The concepts of "validity" and "phenomenon" in philosophy by Herman Lotze and Edmund Husserl
No full textУ статті розглянуто питання співвідношення фундаментальних понять емпіричної метафізики
Германа Лотце та феноменології Едмунда Гусерля. Автор аналізу є розвиток поняття
феномену та значущості в реалістичному, трансцендентальному та екзистенційному варіантах
феноменології E. Гусерля, а також вплив на їх формування філософських розробок Г. Лотце.In the article author describes a question of correlation between fundamental concepts of empirical
metaphysic by Herman Lotze and Edmund Husserl's phenomenology. The author analyses the development
of concepts "phenomenon" and "validity" at realistic, transcendental, and existentional variants of
phenomenology by E. Husserl and its influence by H. Lotze's philosophical investigations
SPECTROSCOPY OF FUNDAMENTAL AND OVERTONE BANDS OF PYRROLE
No full textA. Held and M. Herman, Chem. Phys., 190 (1995) 407. C. Douketis and J.P. Reilly. J. Chem. Phys., 96 (1992) 3431.Author Institution: Laboratoire de Chimie Physique Mol\'{e}culaire, CP160/09, Universit\'e Libre de BruxellesWe have recorded the absorption spectrum of pyrrole at high resolution up to the near infrared range, using a Fourier transform (FT) . We present the rotational analysis of the two strongest fundamental bands, , the N-H stretch and the symmetric CH bend. A very detailed rotational assignment is performed. resulting into extensive sets of rotional parameters. The results will be presented and compared to previous literature results available for the N-H stretch The vibrational identification of the various bands observed on the FT spectrum up to the early overtone range will be discussed
Henri Matisse Drawing: An Eye-Hand Interaction Study Based on Archival Film.
No full textHenri Matisse (1869-1954) attached fundamental importance to his drawings, in particular to the famous Themes et Variations series. These were accomplished following a precise method, starting with arduous life studies and evolving into brilliant spontaneous drawings. A 1946 archival documentary film showing the artist drawing four portraits of his grandson Gerard was shot in such a way as to allow the present author to undertake a detailed eye-hand interaction analysis of the drawing process.
It was found that Matisse’s temporal working rhythm and use of motor memory resulted in a more direct approach than that used by most painters. Taken together with remarks the artist made throughout his lifetime, these results provide a cognitive interpretation of his drawing method
The infant in the news-sheet; an ode against the age.
No full textWoodcut on front and back cover.Cover-title.Mode of access: Internet.Bancroft pfPS3537.S336.I5: Herman G. Scheffauer Collection (C-H 89)Bancroft pfPS3537.S336.I5: Author's signed presentation copy to Beatrice Marshall, Berlin, Nov. 1921.BANC; pfPS3537.S336.I5: In author's handwriting at the bottom of p. [27]: Every line is proof of insanity ?! not of genius as the self deluded author imagined
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