scholarly journals In-Situ Feeding in the Northern Krill, Meganyctiphanes norvegica: A DNA Analysis of Gut Contents

2010 ◽  
Author(s):  
◽  
Alison Cleary
Keyword(s):  
Dna Analysis ◽  
Gut Contents ◽  
Meganyctiphanes Norvegica ◽  
In Situ Feeding

scholarly journals In situ feeding as a new management tool to conserve orphaned Eurasian lynx (lynx lynx)

2021 ◽  
Author(s):  
Joe Premier ◽  
Martin Gahbauer ◽  
Franz Leibl ◽  
Marco Heurich
Keyword(s):  
Management Tool ◽  
Lynx Lynx ◽  
Eurasian Lynx ◽  
In Situ Feeding

Parasites in Antarctic krill guts inferred from DNA sequences

2019 ◽  
Vol 31 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Alison C. Cleary ◽  
Maria C. Casas ◽  
Edward G. Durbin ◽  
Jaime Gómez-Gutiérrez
Keyword(s):  
Dna Sequences ◽  
High Frequency ◽  
Dna Analysis ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Gut Contents ◽  
The West ◽  
West Antarctic ◽  
Wide Range

AbstractThe keystone role of Antarctic krill,Euphausia superbaDana, in Southern Ocean ecosystems, means it is essential to understand the factors controlling their abundance and secondary production. One such factor that remains poorly known is the role of parasites. A recent study of krill diet using DNA analysis of gut contents provided a snapshot of the parasites present within 170E. superbaguts in a small area along the West Antarctic Peninsula. These parasites includedMetschnikowiaspp. fungi,Haptoglossasp. peronosporomycetes,LankesteriaandParalecudinaspp. apicomplexa,Stegophorussp. nematodes, andPseudocolliniaspp. ciliates. Of these parasites,Metschnikowiaspp. fungi andPseudocolliniaspp. ciliates had previously been observed inE. superba, as had other genera of apicomplexans, though notLankesteriaandParalecudina.In contrast, nematodes had previously only been observed in eggs ofE. superba, and there are no literature reports of peronosporomycetes in euphausiids.Pseudocolliniaspp., parasitoids which obligately kill their host, were the most frequently observed infection, with a prevalence of 12%. The wide range of observed parasites and the relatively high frequency of infections suggest parasites may play a more important role than previously acknowledged inE. superbaecology and population dynamics.

Microbial characteristics of a methanogenic phenol-degrading sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 73-78 ◽  
Author(s):  
T. Zhang ◽  
S. Z. Ke ◽  
Y. Liu ◽  
H.P. Fang
Keyword(s):  
Dna Analysis ◽  
Pcr Amplification ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Chain Reaction ◽  
Microbial Characteristics ◽  
Polymerase Chain ◽  
Anaerobic Sludge Blanket

Microbial properties of a methanogenic granular phenol-degrading sludge were characterized using the 16S rRNA/DNA-based techniques, including polymerase chain reaction (PCR) amplification, cloning, DNA sequencing, and fluorescence in situ hybridization (FISH). The sludge was sampled from an upflow anaerobic sludge blanket reactor, which removed 98% of phenol (up to 1260 mg/l) in wastewater at 26°C with 12 hours of hydraulic retention. Based on DNA analysis, the Eubacteria in the sludge was composed of 13 operational taxonomy units (OTUs). Two OTUs, one resembling Clostridium and the other remotely resembling Desulfotomaculum, were likely responsible for the conversion of phenol to benzoate, which was further degraded by five Syntrophus-resembling OTUs to acetate and H2/CO2; methanogens lastly converted acetate and H2/CO2 into methane. The role of six remaining OTUs remains unclear. Overall, the sludge was composed of 26±6% Eubacteria and 74±9% methanogens, of which 54±6% were acetotrophic Methanosaetaceae, 14±3% and 3±2% were hydrogenotrophic Methanomicrobiales and Methanobacteriaceae, respectively.

New species, occurrence records and observations of predation by deep-sea Asteroidea (Echinodermata) from the North Atlantic by NOAA ship Okeanos Explorer

Zootaxa ◽  
2020 ◽  
Vol 4766 (2) ◽  
pp. 201-260 ◽  
Author(s):  
CHRISTOPHER L. MAH
Keyword(s):  
North Atlantic ◽  
Deep Sea ◽  
Substantial Contribution ◽  
The North ◽  
In Situ Observations ◽  
The North Atlantic ◽  
Feeding Observations ◽  
Occurrence Records ◽  
In Situ Feeding

Exploratory cruises by the NOAA Ship Okeanos Explorer have resulted in a substantial contribution in our understanding of deep-sea echinoderm biodiversity, biology, and ecology in the North Atlantic. This includes the description and in situ feeding observations of two, new corallivorous goniasterid species, Evoplosoma nizinskiae n. sp. and Sibogaster bathyheuretor n. sp. Significant in situ observations include a synchronous feeding event including multiple goniasterid asteroids and a cidaroid urchin on a large demosponge, providing new data for understanding echinoderm feeding behavior, including agonistic behavior, in deep-sea settings and new, in situ feeding observations for 28 deep-sea species including the myxasterid Pythonaster atlantidis, the korethrasterid Remaster palmatus and the poorly understood hippasterine goniasterids, Gilbertaster caribaea and Sthenaster emmae. 

scholarly journals Multifrequency target strength of northern krill (Meganyctiphanes norvegica) swimming horizontally

2011 ◽  
Vol 69 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Lucio Calise ◽  
Tor Knutsen
Keyword(s):  
Length Distribution ◽  
Ex Situ ◽  
Target Strength ◽  
Acoustic Backscatter ◽  
Acoustic Measurements ◽  
Acoustic Beams ◽  
Meganyctiphanes Norvegica ◽  
Acoustic Identification ◽  
Made In

Abstract Calise, L., and Knutsen, T. 2012. Multifrequency target strength of northern krill (Meganyctiphanes norvegica) swimming horizontally. – ICES Journal of Marine Science, 69: 119–130. Multifrequency acoustic measurements on ex situ horizontally swimming krill were made in a novel experimental setting. An ensemble of northern krill (Meganyctiphanes norvegica) was introduced to a large enclosure (a mesocosm), and acoustic backscatter was sampled using a multifrequency (70, 120, and 200 kHz) echosounder (Simrad EK60). Two submerged lamps were placed at opposite sides of the mesocosm and switched on and off to induce the krill, by light attraction, to swim horizontally through the acoustic beams. By tracking echoes, animal displacement, swimming speed, and target strength (TS) by frequency were estimated. The dominant and secondary modes of the total-length distribution were 21.8 ± 3.0 and 27.8 ± 2.7 mm, respectively. Although krill orientation was assumed stable and the ping rate was high, the range and inter-ping variability of the average TS values were large, decreasing and increasing with frequency, respectively. The overall TS frequency response observed and concurrent measurements at 120 and 200 kHz confirm the theoretical expectation that the acoustic backscatter from the investigated organisms were confined to the Rayleigh and Geometric scattering regions, a finding that might both aid acoustic identification and size-group separation of in situ northern krill.

scholarly journals Occurrence of Gonadoblastoma in Females with Turner Syndrome and Y Chromosome Material: A Population Study*

2000 ◽  
Vol 85 (9) ◽  
pp. 3199-3202 ◽  
Author(s):  
Claus Højbjerg Gravholt ◽  
Jens Fedder ◽  
Rune Weis Naeraa ◽  
Jørn Müller
Keyword(s):  
Risk Factor ◽  
Turner Syndrome ◽  
Y Chromosome ◽  
Carcinoma In Situ ◽  
Dna Analysis ◽  
Epidemiological Studies ◽  
Histopathological Evaluation ◽  
Primer Sets ◽  
Chromosome Material

Abstract The presence of Y chromosome material in patients with Turner syndrome is a risk factor for the development of gonadoblastoma. However, no cases with gonadoblastoma or other ovarian malignancies have been found in epidemiological studies of cancer, morbidity, or mortality in Turner syndrome. We examined 114 females with Turner syndrome for the presence of Y chromosome material by PCR. Initially, five different primer sets were used. Y Chromosome-positive individuals were further examined with an additional four primer sets. We found 14 (12.2%; 95% confidence interval, 6.9–19.7%) patients who had Y chromosome material. The karyotype in 7 of these patients did not suggest the presence of Y chromosome material. Seven of the patients had been ovariectomized before entering the study due to verified Y chromosome material, whereas three patients were operated upon after the DNA analysis. The histopathological evaluations showed that 1 of the 10 ovariectomized patients actually had a gonadoblastoma. The rest of the patients did not have gonadoblastoma or carcinoma in situ on histopathological evaluation. Three patients (age, >50 yr) positive for Y chromosome material chose not to have ovariectomy performed, and detailed ultrasonographies did not suggest the presence of gonadoblastoma. The frequency of Y chromosome material is high in Turner syndrome (12.2%), but the occurrence of gonadoblastoma among Y-positive patients seems to be low (7–10%), and the risk may have been overestimated in previous studies, perhaps due to problems with selection bias. This study emphasizes the need for prospective unbiased studies.

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