288 research outputs found
Carbon flux for the Caribbean giant barrel sponge Xestospongia muta (Sponge-loop)
Dataset: Carbon fluxBenthic suspension feeders are an important component of aquatic ecosystems, as they mediate benthic-pelagic coupling and the flow of energy and nutrients. There is increasing evidence that sponges are particularly important benthic suspension feeders in aquatic systems and especially on Caribbean coral reefs, where their biomass surpasses that of any other benthic group. The present study investigated the flux of particulate and dissolved organic carbon mediated by the Caribbean giant barrel sponge, Xestospongia muta. A total of 1 L of both incurrent (ambient) and excurrent seawater was collected in situ on Conch Reef, Key Largo, Florida, from 32 individuals with paired 100 mL syringes. Following seawater sample collection, the dimensions of each sponge were measured to obtain sponge volume estimates. Pumping rates were calculated from sponge volume using the relationship of McMurray et al. (2014). For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/685783NSF Division of Ocean Sciences (NSF OCE) OCE-155858
Phenotypic plasticity in the Caribbean sponge Callyspongia vaginalis (Porifera: Haplosclerida)
Sponge morphological plasticity has been a long-standing source of taxonomic difficulty. In the Caribbean, several morphotypes of the sponge Callyspongia vaginalis have been observed. To determine the taxonomic status of three of these morphotypes and their relationship with the congeneric species C. plicifera and C. fallax, we compared the spicule composition, spongin fiber skeleton and sequenced fragments of the mitochondrial genes 16S and COI and nuclear genes 28S and 18S ribosomal RNA. Phylogenetic analyses with ribosomal markers 18S and 28S rRNA confirmed the position of our sequences within the Callyspongiidae. None of the genetic markers provided evidence for consistent differentiation among the three morphotypes of C. vaginalis and C. fallax, and only C. plicifera stood as a distinct species. The 16S mtDNA gene was the most variable molecular marker for this group, presenting a nucleotide variability (π = 0.024) higher than that reported for COI. Unlike recent studies for other sponge genera, our results indicate that species in the genus Callyspongia maintain a high degree of phenotypic plasticity, and that morphological characteristics may not reflect reproductive boundaries in C. vaginalis
Plasticidad fenotípica de la esponja Callyspongia vaginalis (Porifera: Haplosclerida)
Sponge morphological plasticity has been a long-standing source of taxonomic difficulty. In the Caribbean, several morphotypes of the sponge Callyspongia vaginalis have been observed. To determine the taxonomic status of three of these morphotypes and their relationship with the congeneric species C. plicifera and C. fallax, we compared the spicule composition, spongin fiber skeleton and sequenced fragments of the mitochondrial genes 16S and COI and nuclear genes 28S and 18S ribosomal RNA. Phylogenetic analyses with ribosomal markers 18S and 28S rRNA confirmed the position of our sequences within the Callyspongiidae. None of the genetic markers provided evidence for consistent differentiation among the three morphotypes of C. vaginalis and C. fallax, and only C. plicifera stood as a distinct species. The 16S mtDNA gene was the most variable molecular marker for this group, presenting a nucleotide variability (π = 0.024) higher than that reported for COI. Unlike recent studies for other sponge genera, our results indicate that species in the genus Callyspongia maintain a high degree of phenotypic plasticity, and that morphological characteristics may not reflect reproductive boundaries in C. vaginalis.La gran plasticidad morfológica de ciertas esponjas dificulta una correcta clasificación taxonómica. En el Caribe, se han observado varios morfotipos de la esponja Callyspongia vaginalis a nivel de colores y formas. Con el fin de determinar su clasificación taxonómica, se muestrearon y analizaron tres morfotipos de C. vaginalis y sus especies congenéricas C. plicifera y C. fallax. Para cada muestra, se observó la composición espicular y del esqueleto dermal y se secuenciaron parte de los genes mitocondriales 16S y COI y parte de los genes ribosomales 28S y 18S. Los análisis filogenéticos con los genes ribosomales 18S y 28S confirmaron la posición taxonómica de las secuencias obtenidas. Ninguno de los marcadores genéticos utilizados reveló diferencias consistentes entre los tres morfotipos de C. vaginalis y C. fallax, y sólo C. pleicifera apareció en los análisis como una especie distinta. El gen mitocondrial 16S fue el marcador molecular más variable para este grupo, presentando una variabilidad nucleotídica (p = 0.024) superior a la descrita para COI. Nuestros resultados indican que las especies del género Callyspongia presentan una gran plasticidad fenotípica y que estas diferencias morfológicas no suponen barreras reproductivas para C. vaginalis
E-Type Delayed Fluorescence of a Phosphine-Supported Cu_2(μ-NAr_2)_2 Diamond Core: Harvesting Singlet and Triplet Excitons in OLEDs
A highly emissive bis(phosphine)diarylamido dinuclear copper(I) complex (quantum yield = 57%) was shown to exhibit E-type delayed fluorescence by variable temperature emission spectroscopy and photoluminescence decay measurement of doped vapor-deposited films. The lowest energy singlet and triplet excited states were assigned as charge transfer states on the basis of theoretical calculations and the small observed S_1−T_1 energy gap. Vapor-deposited OLEDs doped with the complex in the emissive layer gave a maximum external quantum efficiency of 16.1%, demonstrating that triplet excitons can be harvested very efficiently through the delayed fluorescence channel. The function of the emissive dopant in OLEDs was further probed by several physical methods, including electrically detected EPR, cyclic voltammetry, and photoluminescence in the presence of applied current
Fast Detection of Two Smenamide Family Members Using Molecular Networking.
Caribbean sponges of the genus Smenospongia are a prolific source of chlorinated secondary metabolites. The use of molecular networking as a powerful dereplication tool revealed in the metabolome of S. aurea two new members of the smenamide family, namely smenamide F (1) and G (2). The structure of smenamide F (1) and G (2) was determined by spectroscopic analysis (NMR, MS, ECD). The relative and the absolute configuration at C-13, C-15, and C-16 was determined on the basis of the conformational rigidity of a 1,3-disubstituted alkyl chain system (i.e., the C-12/C-18 segment of compound (1). Smenamide F (1) and G (2) were shown to exert a selective moderate antiproliferative activity against cancer cell lines MCF-7 and MDA-MB-231, while being inactive against MG-63
The pathology of sponge orange band disease affecting the Caribbean barrel sponge Xestospongia muta
The aim of this study was to examine sponge orange band (SOB) disease affecting the prominent Caribbean sponge Xestospongia muta. Scanning and transmission electron microscopy revealed that SOB is accompanied by the massive destruction of the pinacoderm. Chlorophyll a content and the main secondary metabolites, tetrahydrofurans, characteristic of X. muta, were significantly lower in bleached than in healthy tissues. Denaturing gradient gel electrophoresis using cyanobacteria-specific 16S rRNA gene primers revealed a distinct shift from the Synechococcus/Prochlorococcus clade of sponge symbionts towards several clades of unspecific cyanobacteria, including lineages associated with coral disease (i.e. Leptolyngbya sp.). Underwater infection experiments were conducted by transplanting bleached cores into healthy individuals, but revealed no signs of SOB development. This study provided no evidence for the involvement of a specific microbial pathogen as an etiologic agent of disease; hence, the cause of SOB disease in X. muta remains unidentified
Transitoriness in cancer patients: a cross-sectional survey of lung and gastrointestinal cancer patients
Objective: Despite earlier diagnosis and advancements in treatment, cancer remains a leading cause of death in the world (13% of all deaths according to the World Health Organization) among men and women. Cancer accounts for approximately 20% of the deaths in the USA every year. Here, we report the findings from a cross-sectional survey of psychosocial factors in lung and gastrointestinal cancer patients. The aim of the study was to explore the associations among transitoriness, uncertainty, and locus of control (LOC) with quality of life. Transitoriness is defined as a person's confrontation with life's finitude due to a cancer diagnosis. Methods: A total of 126 patients with lung or gastrointestinal cancer completed eight self-reporting questionnaires addressing demographics, spiritual perspective, symptom burden, transitoriness, uncertainty, LOC, and quality of life. Results: Transitoriness, uncertainty, and LOC were significantly associated with one another (r = 0.3267, p = 0.0002/r = 0.1994, p = 0.0252, respectively). LOC/belief in chance has a significant inverse relationship with patients' quality of life (r = −0.2505, p = 0.0047). Transitoriness, uncertainty, and LOC were found to have a significant inverse relationship with patients' quality of life (transitoriness state: r = −0.5363, p = 0.0000/trait: r = −0.4629, p = 0.0000/uncertainty: r = −0.4929, p = 0.0000/internal LOC: r = 0.1759, p = 0.0489/chance LOC: r = −0.2505, p = 0.0047). Conclusion: Transitoriness, uncertainty, and LOC are important concepts as they adversely influence patients' quality of life. Incorporating this finding into the care of cancer patients may provide them with the support they need to cope with treatment and maintenance of a positive quality of lif
Unusual morphotypes of the giant barrel sponge off the coast of Barbados
Giant barrel sponges (GBSs) belong to a cryptic species complex (Xestospongia spp.) and are found on tropical reefs worldwide. Over their range, including most of the Caribbean, GBSs have a cylindrical shape, with variation in height, diameter and surface complexity. However, off the southwest coast of Barbados, GBSs mostly exhibit a clam shape or a tub shape, interspersed with a few that have the normal barrel morphotype, suggesting that this variation is not due to environmental factors. Haplotype identification (mtDNA-COI) of six clam and six normal sponges indicated no clear genetic differentiation based on morphotype; hence, this morphological variation remains unexplained
Constraining the bright-end of the UV luminosity function for z 7-9 galaxies: results from CANDELS/GOODS-South
The recent Hubble Space Telescope near-infrared imaging with the Wide-Field Camera #3 (WFC 3) of the Great Observatories Origins Deep Survey South (GOODS-S) field in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) programme covering nearly 100 arcmin2, along with already existing Advanced Camera for Surveys optical data, makes possible the search for bright galaxy candidates at redshift z ≈ 7–9 using the Lyman break technique. We present the first analysis of z′-drop z ≈ 7 candidate galaxies in this area, finding 19 objects. We also analyse Y-drops at z ≈ 8, trebling the number of bright (HAB < 27 mag) Y-drops from our previous work, and compare our results with those of other groups based on the same data. The bright high-redshift galaxy candidates we find serve to better constrain the bright end of the luminosity function at those redshift, and may also be more amenable to spectroscopic confirmation than the fainter ones presented in various previous work on the smaller fields (the Hubble Ultra Deep Field and the WFC 3 Early Release Science observations). We also look at the agreement with previous luminosity functions derived from WFC 3 drop-out counts, finding a generally good agreement, except for the luminosity function of Yan et al. at z ≈ 8, which is strongly ruled out
The HMA-LMA dichotomy revisited: an electronmicroscopical survey of 56 sponge species
The dichotomy between high microbial abundance (HMA) and low microbial abundance (LMA) sponges has been long recognized. In the present study, 56 sponge species from three geographic regions (greater Caribbean, Mediterranean, Red Sea) were investigated by transmission electron microscopy for the presence of microorganisms in the mesohyl matrix. Additionally, bacterial enumeration by DAPI-counting was performed on a subset of samples. Of the 56 species investigated, 28 were identified as belonging to the HMA and 28 to the LMA category. The sponge orders Agelasida and Verongida consisted exclusively of HMA species, and the Poecilosclerida were composed only of LMA sponges. Other taxa contained both types of microbial associations (e.g., marine Haplosclerida, Homoscleromorpha, Dictyoceratida), and a clear phylogenetic pattern could not be identified. For a few sponge species, an intermediate microbial load was determined, and the microscopy data did not suffice to reliably determine HMA or LMA status. To experimentally determine the HMA or LMA status of a sponge species, we therefore recommend a combination of transmission electron microscopy and 16S rRNA gene sequence data. This study significantly expands previous reports on microbial abundances in sponge tissues and contributes to a better understanding of the HMA-LMA dichotomy in sponge-microbe symbioses
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