1,721,021 research outputs found
Optical characterization and redescription of the South Pacific firefly Bourgeoisia hypocrita Olivier (Coleoptera: Lampyridae: Luciolinae)
No full textDeheyn, Dimitri D., Ballantyne, Lesley A. (2009): Optical characterization and redescription of the South Pacific firefly Bourgeoisia hypocrita Olivier (Coleoptera: Lampyridae: Luciolinae). Zootaxa 2129: 47-62, DOI: 10.5281/zenodo.18833
Anthropogenic contaminants in Venice Lagoon sediments and their pore fluids: Results from the SIOSED Project
No full textInvestigations of sediment geochemistry and interstitial water chemistry during SIOSED (Scripps Institution of Oceanography Sediment Research Project) revealed information about the characteristics and depth range of contamination in sediments associated with dredging operations in the Venice Lagoon, Italy. Results from gravity cores indicate that contamination ranges larger and deeper in sediments associated with Porto Marghera and the Venice Industrial Zone compared with sediments at greater distances from dredged shipping canals or pollution sources. The effects of sediment re-deposition were evaluated from a pore water chemistry study of artificial banks constructed by placing dredged canal sediments on top of background sediments. Rapid decreases in dissolved sulfate associated with increases in alkalinity, sulfide, and nutrients, such as ammonium and phosphate, indicate that sediment dredging led to enhanced bio-chemical diagenesis of organic matter near the surface of the re-deposited sediments. Continued diagenesis of organic matter in re-deposited sediments maintained extrema in alkalinity, dissolved sulfate, sulfide, and ammonium. The artificial banks retained their pore water signatures over the duration of the project. Sediment redistribution can thus cause important changes in pore water profiles, as observed from the chemistry in long cores studied in this program
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Investigation of Chaetopterus variopedatus Mucus Bioluminescence Utilizing Cofactor Fe2+ and other Metal Ions
Full text linkThe photoprotein of marine polychaete, Chaetopterus variopedatus, has been under investigation for decades because of its unique long-lasting light production ability and the potential of utilization in biochemical research as a reporter molecule. However, the exact light-producing mechanism remains unknown except that Fe2+ acts as the cofactor for the photoprotein. The goal of this thesis is to investigate this bioluminescence reaction pathway and to hopefully extract the previously unknown photoprotein. we discovered a preliminary relationship between Fe2+ (photoprotein cofactor) concentration and mucus bioluminescence—a stimulation-inhibition dose response curve where ferrous iron stimulates light at a low concentration (£ 0.1 mM added) and starts to inhibit light as concentration increases (> 0.1 mM). Evidence suggests that Co2+ and Zn2+ are both competitive inhibitors for binding to the cofactor site on photoprotein and for bioluminescence. Co2+ has a stronger affinity than Fe2+ while Zn2+ has a lower affinity compared to Fe2+. We were able to purify Fe2+ binding protein from the mucus complex using Fe2+-affinity column. By using Co2+ as a substitute cofactor, we extracted from the mucus a light-inducing protein (37 kDa), which is a potential candidate for photoprotein or a protein that plays a role in the light production pathway
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Characterization of the light producing system from the luminous brittlestar Ophiopsila californica (Echinodermata)
Full text linkLight producing proteins (photoproteins) are attractive molecules to study because of their potential applications in biotechnology and biomedicine. Photoproteins have been identified in several different phyla, however a photoprotein from the phylum Echinodermata has yet to be characterized. The goal in this work is to extract the calcium-dependent photoprotein from brittlestar Ophiopsila californica for purification and identification. The photoprotein was successfully extracted while maintaining activity. Three chromatographic techniques were used to separate the functional photoprotein from other constituents in the brittlestar extracts. The light producing fractions from each of these chromatography methods were analyzed using gel electrophoresis in attempt to identify a band that correlates with the amount of light production when comparing multiple fractions. A ~45 kDa band showed this positive correlation throughout each purification step. This band was characterized by ESI-QTOF-MS but did not result in the identification of a new photoprotein. Similar methods were attempted on isolated photocytes (light producing cells). However nearly all light producing activity was lost when attempting to extract the photoprotein from the cell. This indicated that the photoprotein relies on an intact membrane in order to function. This leads to the idea that the activation of this photoprotein could be different than the one previously proposed
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Assessing the impact of climate-change related lower pH and lower salinity conditions on the physiology and behavior of a luminous marine invertebrate
Full text linkIncreases in water precipitation and ocean acidification___consequences of climate change and CO2 emissions___affects the physiology and behavior of marine invertebrates. We postulated changes would occur in nervous system-controlled predator defense mechanisms, including bioluminescence, arm regeneration, and neuro-coordination abilities, such as the ability to return to upright after being flipped upside down. This hypothesis was tested by exposing the luminous brittlestar Amphipholis squamata (Echinodermata) to conditions of lower pH (pH 7.7, from pH 7.9), lower salinity (25 PSU, from 33 PSU), and lower pH and salinity combined. Exposure to the changes in experimental seawater chemistry for up to 7 weeks resulted in slower flipping times in the low salinity and in the low pH treatments and in high levels of leaking light in their bioluminescence response. These results indicated a negative effect on the neuro-muscular coordination and possibly the neuro-control of the light production. Brittlestar arms exposed to lower pH and salinity conditions experienced stunted regenerative growth, evidenced by shorter and narrower regenerative arm tips that were also less calcified. Brittlestars demonstrated difficulty expressing normal (control) predator defense functions following a 7-week exposure to low salinity conditions suggesting long term exposure resulted in prolonged effects on maintenance and repair mechanisms sustaining the brittlestar defense strategies. These data suggest compensatory energy reallocation toward maintaining normal function of other vital processes under stress. Quantifying the brittlestars behavioral and physiological responses can provide a clue for how their survivability will be impacted under projected low pH and low salinity conditions in the future
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Metals concentration in salt marshes plants and kelp around San Diego: A window to environment quality
Full text linkThis project was developed into two avenues aiming at assessing levels of metals in kelp and salt marsh plants in the San Diego area. This information was then used to address whether metals levels found in kelp and salt marsh plants reflect bioavailable metals in the environment, which could help their use in environmental monitoring
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Etude de la bioluminescence chez l'ophiure amphipholis squamata (Delle Chiaje, 1828) (Echinodermata) :structure des sites photogènes; modalités de l'expression et fonction de la bioluminescence
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Bourgeoisia hypocrita Olivier
No full textBourgeoisia hypocrita (Olivier) (Figs 3 & 5) Luciola hypocrita Olivier, 1888: 60; 1902: 80. Bourgeoisia hypocrita (Olivier). Olivier, 1908: 17. McDermott, 1966: 118. Ballantyne, 1968: 124. Ballantyne & McLean, 1970: 234. Luciola nigra McDermott, 1966: 110 (unnecessary new name for L. atra Pic). syn. nov. Luciola atra Pic, 1928: 58. syn. nov. Type material. Holotypes. Luciola atra Pic. Male. FIJI 18.00 S, 178.00 labelled 1. handwritten Luciola sp. (Olivier dit); 2 handwritten Luciola atra n s; 3 symbol; 4 printed black ink Ins. Fiji (MNHN). Luciola hypocrita Olivier). Male. FIJI 18.00 S, 178.00 labelled 1. handwritten on pink paper Luciola hypocrita; printed Ern. Oliv.; 2 printed SPECIMEN TYPICUM ORIGINALE AUCTORIS Ern. Olivier; 3. handwritten Fidjie Ins. (MNHN). Other material examined. FIJI 18.00 S, 178.00 3 males (poor condition) 13 larvae, J. Brophy (ANIC). 18.04S, 178.27E, Viti-Levu, Colo-i-suva, 22.vii. 1987, G. B. Monteith QM berleaseate 786 plantation forest, 150m litter and moss, male (QM). Viti Levu, Fiji, Nananu-I-Ra, October 2007, D. D. Deheyn, 2 females (ANIC). Diagnosis. Distinguished from other Luciolinae males by the occurrence in Fiji, the dark deep greyish black dorsal colouration, the pale brown or yellow ventral colour with light organs restricted to anterolateral plaques in ventrite 6 only; females brachelytral with hind wings vestigial, elytra and pronotum coloured as for male, remainder of body paler brown or yellow; larvae (associated by label data) very deep charcoal greyblack, protergum with short paired rounded projections at posterolateral corners, thoracic terga with lateral projections and all abdominal terga except terminal with paired projections at posterolateral corners. As this is the only recorded species of firefly from Fiji the females and larvae are associated on that basis. Description. Male (Fig. 5) Body 8.4–8.9 mm long; approximately 3.0 mm wide; width/length 3 / 1. Colour. Pronotum (Figs 5 C, D, E) dull deep charcoal grey; MN slightly paler grey and semitransparent; MS and elytra shiny deep grey almost black; head deep grey between eyes, antennae and palpi paler brownish grey; ventral body colour pale brown (Fig. 5 B) (yellow in Suva male Fig. 5 A) except for waxy white light organs in anterolateral areas of V 6; legs with pale brown or yellow coxae and base of femora, posterior face of rest of femora mid brown, anterior face of femora mid brown in apical half, tibiae and tarsi dark brown; all tergites pale brown (yellow in Suva male). Pronotum (Figs 5 C, D, E, F) 1.6–1.7 mm long; 2.5–2.8 mm wide; Width/length 1.5; 1 / 5 as long as whole body; dorsal surface lacking irregularities in posterolateral areas and longitudinal groove in lateral areas; punctation broad, shallow, dense. Anterior margin not explanate. Pronotum wider across posterior area than rest; pronotal width subequal to humeral width; anterolateral corners rounded obtuse; lateral margins in anterior half diverge posteriorly slightly; lateral margins in posterior half converge with rounded convergence (pronotum close to sub-parallel-sided); lacking indentation at mid-point, margins may be very shallowly indented at about 1 / 4 their length from posterior margin; lateral margins lacking sinuousity in either horizontal or vertical plane; lateral margins lacking indentation in lateral margin just anterior to posterolateral corner, and irregularities at corner; posterolateral corners rounded obtuse; posterolateral corners project as far as median posterior margin, separated by shallow emargination. Hypomera closed. Median area of hypomeron not elevated vertically; anterior area of hypomeron not closely adpressed, posterior area flat closely adpressed; pronotal width/GHW 1.6. Elytron (Figs 5 C, D): punctation moderately dense, irregular, punctures not well defined in outline, not linear, not as large as pronotum, nor widely and evenly spaced; apices not deflexed; epipleuron and suture extend beyond mid-point, to apex but not as ridge around apex, with neither thickened in apical half; 2 interstitial lines (1, 2) not exceeding suture; elytral carina absent; in horizontal specimen viewed from below epipleuron at base either covering or almost covering humerus, in horizontal specimen viewed from above epipleuron becoming visible at sides of elytron anterior to posterior margin of MS; epipleuron developed as lateral ridge along most of length; sutural margins approximate along most of length in closed elytra; lateral margins slightly convex sided. Head (Figs 5 G, H): GHW 1.8–2.0 mm; SIW 0.2–0.3 mm; SIW/GHW 1 / 9; ASD W, non-lunate, not strongly flattened, inner margin not dentate. Antennae 11 segmented; filiform; length>GHW and 4 times as long as wide; lacking paraprocts; slightly asymmetrical in posterior area where sheath sternite emarginated on right side from point of attachment of tergite; sternite not angulate on L or R sides, not subparallel-sided, posterior margin entire, rounded, not emarginated on either side preapically; anterior half of sternite broad, apically rounded; tergite lacking lateral arms extending anteriorly at sides of sheath sternite; tergite lacking projecting pieces along posterior margin of tergite 9; anterior margin of tergite 9 lacking transverse band. Aedeagus L/W W; lacking tubercles along anterior margin, posterolateral corners bifurcate into two slender apically rounded projections; margins of median line slightly and irregularly ridged; posterolateral corners of terga 2, 3 with single slender apically rounded projection inclined obliquely to median line; posterior margin of terga 1–3 broadly rounded, slightly produced to either side of mid line; lateral margins of terga 2, 3 irregular; posterolateral corners of terga 4–11 (abdominal segments 1–8) bifurcated into slender apically rounded projections inclining obliquely to median line; posterior margin of terga 4–11 to either side of median line like that for thoracic terga, highest point of the area produced into small rounded area; lateral margins of terminal tergum entire, lacking projections, converging slightly posteriorly, with posterolateral corners rounded, not produced, posterior margin rounded; punctures in anterior half of terga 2–11 larger than rest, paler than rest; with whitish brush of hairs from apex of tibiotarsus, enveloping the apical tarsungulus. Head of general form of Pteroptyx valida (Ballantyne & Menayah, 2002), flattened, subrectangular, with well developed epicranial suture extending along either side of frontoclypeus to anterior margin which is slightly and narrowly medially emarginated; mandibles lacking inner teeth.Published as part of Deheyn, Dimitri D. & Ballantyne, Lesley A., 2009, Optical characterization and redescription of the South Pacific firefly Bourgeoisia hypocrita Olivier (Coleoptera: Lampyridae: Luciolinae), pp. 47-62 in Zootaxa 2129 on pages 51-56, DOI: 10.5281/zenodo.18833
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