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31.
Diversity of Siphonaria Sowerby I, 1823 (Gastropoda,Siphonariidae) in the Seychelles Bank and beyond
Molecular phylogenetic studies have shown that the characters of the reduced shell of the false limpets of the genus Siphonaria Sowerby I, 1823 are highly variable and often insufficient for species delimitation. The taxonomy and distribution of Siphonaria in the Indian Ocean are poorly known. We sampled Siphonaria in the Seychelles Bank to check the occurrence of recorded species using DNA sequences and to study the paths through which Siphonaria species have colonised the Seychelles Bank by reconstructing their phylogenetic relationships. Analyses of a dataset comprising 16 S rRNA gene sequences of 33 specimens from the Seychelles Bank and 300 additional Siphonaria sequences from other regions from GenBank with various methods for species delimitation resulted in 19–102 primary species hypotheses. Assemble Species by Automatic Partitioning provided a conservative estimate of the species number (42) in which several indisputable species were lumped. The results of Automatic Barcode Gap Discovery depended strongly on the assumed prior maximum intraspecific divergence, whereas the tree-based methods Generalised Mixed Yule Coalescent and Poisson Tree Processes resulted in high overestimates. The specimens from the Seychelles Bank represent three clades, belonging to the Siphonaria ‘atra’ group, the Siphonaria ‘normalis’ group and a possibly undescribed species recorded previously only from Hainan. At least two of the three species recorded from the Seychelles Bank came from the east, i.e., from the Coral Triangle in the Indo-Australian Archipelago, the region with the highest marine biodiversity worldwide. A major transport mechanism across the Indian Ocean was probably the South Equatorial Current. 相似文献
32.
Sven Rossel Patricia Kaiser Maya Bode-Dalby Jasmin Renz Silke Laakmann Holger Auel Wilhelm Hagen Pedro Martínez Arbizu Janna Peters 《Molecular ecology resources》2023,23(2):382-395
Species identification is pivotal in biodiversity assessments and proteomic fingerprinting by MALDI-TOF mass spectrometry has already been shown to reliably identify calanoid copepods to species level. However, MALDI-TOF data may contain more information beyond mere species identification. In this study, we investigated different ontogenetic stages (copepodids C1–C6 females) of three co-occurring Calanus species from the Arctic Fram Strait, which cannot be identified to species level based on morphological characters alone. Differentiation of the three species based on mass spectrometry data was without any error. In addition, a clear stage-specific signal was detected in all species, supported by clustering approaches as well as machine learning using Random Forest. More complex mass spectra in later ontogenetic stages as well as relative intensities of certain mass peaks were found as the main drivers of stage distinction in these species. Through a dilution series, we were able to show that this did not result from the higher amount of biomass that was used in tissue processing of the larger stages. Finally, the data were tested in a simulation for application in a real biodiversity assessment by using Random Forest for stage classification of specimens absent from the training data. This resulted in a successful stage-identification rate of almost 90%, making proteomic fingerprinting a promising tool to investigate polewards shifts of Atlantic Calanus species and, in general, to assess stage compositions in biodiversity assessments of Calanoida, which can be notoriously difficult using conventional identification methods. 相似文献
33.
Holger Hackstein Gerhard Jahn Holger Kirchner Gregor Bein 《Histochemistry and cell biology》1996,106(2):229-234
Radioactive in situ hybridization techniques or enzymatic detection procedures of hapten-modified human cytomegalovirus (HCMV)
probes have been widely used for studying the infection of peripheral blood leukocytes with HCMV. This report describes significant
improvements in terms of signal resolution which can be obtained by applying a highly sensitive fluorescence in situ hybridization
(FISH) technique in conjunction with a large subgenomic HCMV DNA probe. Three cosmid clones spanning 119.1 kb of the HCMV
genome (230 kb) were used to construct the digoxigenin-11-dUTP-labeled probe which was found to be superior to a total HCMV
probe representing the entire genome. Crucial hybridization parameters were analyzed systematically in order to ensure optimal
resolution power and sensitivity. The protocol was successfully applied to HCMV-infected fibroblasts and peripheral blood
leukocytes of 12 transplant patients and unambiguously facilitated the precise intracellular localization of HCMV genomes
in infected cells. Because of its excellent resolution properties, accompanied by the virtual absence by any background staining,
we recommend the use of this protocol as a sensitive approach for further virological analyses of the interactions between
HCMV and peripheral blood leukocytes at the single-cell level.
Accepted: 16 February 1996 相似文献
34.
35.
Molecular mechanisms of endotoxin activity 总被引:20,自引:0,他引:20
Jens Schletter Holger Heine Artur J. Ulmer Ernst T. Rietschel 《Archives of microbiology》1995,164(6):383-389
Endotoxin (lipopolysaccharide, LPS), a constitutent of the outer membrane of the cell wall of gramnegative bacteria, exerts
a wide variety of biological effects in humans. This review focuses on the molecular mechanisms underlying these activities
and discusses structure-function relationships of the endotoxin molecule, its interaction with humoral and cellular receptors
involved in cell activation, and transmembrane and intra-cellular signal transduction pathways. 相似文献
36.
Ferdinand Bohlmann Pahup Singh Jasmin Jakupovic Robert M. King Harold Robinson 《Phytochemistry》1982,21(2):371-374
An investigation of the aerial parts of Chromolaena chasleae afforded a prostaglandin-like acid, whose structure followed from the 1H NMR spectral data and from the reaction with periodate, which afforded a hemiacetal. From a new Chromolaena species, three novel cadinene derivatives were isolated, which were closely related to those isolated previously from this genus. 相似文献
37.
Ferdinand Bohlmann Wolfgang Kramp Jasmin Jakupovic Harold Robinson Robert M. King 《Phytochemistry》1982,21(2):399-403
The aerial parts of Baccharis minutiflora afforded in addition to known compounds eight new ent-kaurane derivatives, one being a homo kaurane, while the aerial parts of B. alatemoides gave two pairs of epimeric clerodane derivatives, which, however, had to be modified chemically before they could be separated. The stereochemistry of these diterpenes could not be elucidated with certainty. 相似文献
38.
Ferdinand Bohlmann Maniruddin Ahmed Harold Robinson Robert M. King 《Phytochemistry》1982,21(7):1675-1678
The investigation of the aerial parts of a variety of Enhydra fluctuans afforded in addition to 4-hydroxyfarnesyl acetate and fluctuadin five new melampolides elucidated by high field 1H NMR spectroscopy. The chemotaxonomic situation is discussed briefly. 相似文献
39.
Ferdinand Bohlmann Naleen Borthakur Robert M. King Harold Robinson 《Phytochemistry》1982,21(7):1793-1794
Calea reticulata afforded in addition to known compounds two new sesquiterpenes. These were germacrane and eudesmane derivatives, identified as germacra-4(15),5,10(14)-trien-1-one and 6-epi-β-verbesinol coumarate, respectively. 相似文献
40.
Ferdinand Bohlmann Rajinder K. Gupta Robert M.^King Harold Robinson 《Phytochemistry》1982,21(10):2593-2595
Calea villosa afforded three new sesquiterpene lactones, two furanoheliangolides and an epoxy- germacranolide, as well as several known compounds. The structures were elucidated by spectroscopic methods. 相似文献