236 research outputs found
No more time to stay ‘single’ in the detection of Anisakis pegreffii, A. simplex (s. s.) and hybridization events between them: a multi-marker nuclear genotyping approach
A multi-marker nuclear genotyping approach was performed on larval and adult specimens of Anisakis spp. (N = 689) collected from fish and cetaceans in allopatric and sympatric areas of the two species Anisakis pegreffii and Anisakis simplex
(s. s.), in order to: (1) identify specimens belonging to the parental taxa by using nuclear markers (allozymes loci) and sequence analysis of a new diagnostic nuclear DNA locus (i.e. partial sequence of the EF1 α−1 nDNA region) and (2) recognize hybrid categories. According to the Bayesian clustering algorithms, based on those markers, most of the individuals
(N = 678) were identified as the parental species [i.e. A. pegreffii or A. simplex (s. s.)], whereas a smaller portion (N = 11)
were recognized as F1 hybrids. Discordant results were obtained when using the polymerase chain reaction–restriction
fragment length polymorphisms (PCR–RFLPs) of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) on
the same specimens, which indicated the occurrence of a large number of ‘hybrids’ both in sympatry and allopatry.
These findings raise the question of possible misidentification of specimens belonging to the two parental Anisakis and
their hybrid categories derived from the application of that single marker (i.e. PCR–RFLPs analysis of the ITS of
rDNA). Finally, Bayesian clustering, using allozymes and EF1 α−1 nDNA markers, has demonstrated that hybridization
between A. pegreffii and A. simplex (s. s.) is a contemporary phenomenon in sympatric areas, while no introgressive hybridization takes place between the two species
Infection levels and species diversity of ascaridoid nematodes in Atlantic cod, Gadus morhua, are correlated with geographic area and fish size
Atlantic cod (Gadus morhua) is among the most important commercial fish species on the world market. Its
infection by ascaridoid nematodes has long been known, Pseudoterranova even being named cod worm. In the
present study, 755 individuals were sampled in the Barents, Baltic and North Seas during 2012–2014.
Prevalences for Anisakis in whole fish and in fillets in the different fishing areas varied from 16 to 100% and
from 12 to 90% respectively. Abundance was also greatly influenced by the sampling area. Generalized additive
model results indicate higher numbers of Anisakis in the North Sea, even after the larger body size was accounted
for. Numbers and prevalence of Anisakis were positively related to fish length or weight. The prevalence of
parasites in whole fish and in fillets was also influenced by the season, with the spring displaying a peak for the
prevalence in whole fish and, at the same time, a drop for the prevalence in fillets. Whereas 46% of cod had
Anisakis larvae in their fillets, the majority (39%) had parasites mainly in the ventral part of the fillet and only
12% had parasites in their dorsal part. This observation is of importance for the processing of the fish. Indeed,
the trimming of the ventral part of the cod fillet would allow the almost total elimination of ascaridoids except
for cod from the Baltic Sea where there was no difference between the dorsal and the ventral part.
The presence of other ascaridoid genera was also noticeable in some areas. For Pseudoterranova, the highest
prevalence (45%) in whole fish was observed in the Northern North Sea, whereas the other areas had prevalences between 3 and 16%. Contracaecum was present in every commercial size cod sampled in the Baltic Sea
with an intensity of up to 96 worms but no Contracaecum was isolated from the Central North Sea. Non-zoonotic
Hysterothylacium was absent from the Baltic Sea but with a prevalence of 83% in the Barents and the Northern
North Sea.
A subsample of worms was identified with genetic-molecular tools and assigned to the species A. simplex (s.s.),
A. pegreffii, P. decipiens (s.s.), P. krabbei, C. osculatum and H. aduncum. In addition to high prevalence and
abundance values, the cod sampled in this study presented a diversity of ascaridoid nematodes with a majority of
fish displaying a co-infection. Out of 295 whole infected fish, 269 were co-infected by at least 2 genera
Differences in gene expression profiles of seven target proteins in third-stage larvae of anisakis simplex (Sensu stricto) by sites of infection in blue whiting (micromesistius poutassou)
The third-stage larvae of the parasitic nematode genus Anisakis tend to encapsulate in different tissues including the musculature of fish. Host tissue penetration and degradation involve both mechanic processes and the production of proteins encoded by an array of genes. Investigating larval gene profiles during the fish infection has relevance in understanding biological traits in the parasite’s adaptive ability to cope with the fish hosts’ defense responses. The present study aimed to investigate the gene expression levels of some proteins in L3 of A. simplex (s.s.) infecting different tissues of blue whiting Micromesistius poutassou, a common fish host of the parasite in the NE Atlantic. The following genes encoding for Anisakis spp. proteins were studied: Kunitz-type trypsin inhibitor (TI), hemoglobin (hb), glycoprotein (GP), trehalase (treh), zinc metallopeptidase 13 (nas 13), ubiquitin-protein ligase (hyd) and sideroflexin 2 (sfxn 2). Significant differences in gene transcripts (by quantitative real-time PCR, qPCR) were observed in larvae located in various tissues of the fish host, with respect to the control. ANOVA analysis showed that relative gene expression levels of the seven target genes in the larvae are linked to the infection site in the fish host. Genes encoding some of the target proteins seem to be involved in the host tissue migration and survival of the parasite in the hostile target tissues of the fish host
Long-term investigation of the ‘soft flesh’ condition in Northeast Atlantic mackerel induced by the myxosporean parasite Kudoa thyrsites (Cnidaria, Myxozoa). Temporal trends and new molecular epidemiological observations
Northeast Atlantic (NEA) mackerel (Scomber scombrus, Scombridae) represents an economically important target for the Norwegian pelagic fishing industry. Despite the commercial significance of NEA mackerel, little is known about the infections with the myxosporean parasite Kudoa thyrsites (Kudoidae). The parasite may cause post-mortem myoliquefaction of the fish skeletal muscle and therefore reduce the quality of the fish product. In this study, we examined 'soft flesh' occurrence in commercial size groups of NEA 'autumn mackerel' caught between 2007 and 2020, and investigated the prevalence and density of K. thyrsites (qPCR) and how they related to the occurrence of 'soft flesh'. The present study is the first long-term investigation of the occurrence of K. thyrsites-induced 'soft flesh' in NEA mackerel. After appearing stable for over a decade, the 'soft flesh' occurrence increased three-to six-fold in 2019 and 2020. This increase, together with the findings that 'soft flesh' seems primarily to affect the commercially most valuable mackerel size group (>400 g), may have important implications for the fishing industry and the fishery management. Molecular analysis (qPCR) suggests that the prevalence of K. thyrsites is substantially higher than 'soft flesh' occurrence. The majority (87.4%, n = 76/87) of infected mackerel did not develop 'soft flesh' and only individuals with high parasite density in the musculature (12.6%, n = 11/87) showed the condition. Therefore, qPCR analyses should be used for estimating the prevalence of K. thyrsites in fish. The method may also be used to assess the risk of NEA mackerel to develop post-mortem 'soft flesh'
Characterization of Pseudoterranova ceticola (Nematoda: Anisakidae) larvae from meso/bathypelagic fishes off Macaronesia (NW Africa waters)
The genus Pseudoterranova includes parasite species of cetaceans and pinnipeds. The third stage larva (L3) of seal-infecting species occur in second intermediate or paratenic fish hosts mainly in neritic waters. This study firstly describes a Pseudoterranova L3 from meso/bathypelagic fishes off Macaronesia. L3s were morphologically and genetically studied by light microscopy and sequencing of the mtDNA cox2 and entire ITS rDNA genes. Bayesian inferences were performed with sequences from the larvae and selected sequences from GenBank. The nematode L3s were molecularly identified as Pseudoterranova ceticola, a parasite of kogiid whales. Such larvae were collected from Bolinichthys indicus, Chauliodus danae, Eupharynx pelecanoides, Diaphus rafinesquii, D. mollis, Diretmus argenteus and Maulisia argipalla. They mainly occurred in the viscera of these fishes. Pseudoterranova ceticola L3 were small (< 12 mm) and whitish, and a prominent characteristic is a circumoral ridge extending from the ventral boring tooth which differentiate them from Pseudoterranova spp. L3 maturing in pinnipeds and Terranova sensu lato larvae that mature in poikilotherms. The shape of the tail: conical, long, pointed, ventrally curved and lacking mucron also distinguish these larvae from those of the pinniped-infecting Pseudoterranova spp. Phylogenetic analyses based on mtDNA cox2 and ITS rDNA sequences suggest that P. ceticola is closely related to Skrjabinisakis spp., and not with Pseudoterranova spp. parasitizing pinnipeds. The related species Skrjabinisakis paggiae, S. brevispiculata and S. physeteris (until recently belonging to genus Anisakis), are as P. ceticola also parasites of physeteroid cetaceans. The morphology and morphological variation of the larvae of the cetacean parasite P. ceticola is thoroughly described for the first time. These L3 can readily be morphologically distinguished from those of the pinniped-infecting Pseudoterranova spp. The parasite likely completes its life cycle in the mesopelagic and bathypelagic realm, with meso/bathypelagic fish as 2nd intermediate or paratenic hosts and kogiids as final host. Thus, Pseudoterranova from cetaceans appear to be morphologically, genetically, and ecologically differentiated to those from pinnipeds, suggesting that they are not congeneric.publishedVersio
Wave Packet Echoes in the Motion of Trapped Atoms
We experimentally demonstrate and systematically study the stimulated revival
(echo) of motional wave packet oscillations. For this purpose, we prepare wave
packets in an optical lattice by non-adiabatically shifting the potential and
stimulate their reoccurence by a second shift after a variable time delay. This
technique, analogous to spin echoes, enables one even in the presence of strong
dephasing to determine the coherence time of the wave packets. We find that for
strongly bound atoms it is comparable to the cooling time and much longer than
the inverse of the photon scattering rate
Camallanus cotti Fujita, 1927 (Nematoda, Camallanoidea) in ornamental aquarium fishes: pathology and morphology
Efficiency of Collisionally-activated dissociation and 193-nm photodissociation of peptide ions in fourier transform mass spectrometry
AbstractFor tandem mass spectrometry, the Fourier transform instrument exhibits advantages for the use of collisionally-activated dissociation (CAD). The CAD energy deposited in larger ions can be greatly increased by extending the collision time to as much as 120 s, and the efficiency of trapping and measuring CAD product ions in many times greater than the found for triple-quadrupole or magnetic sector instruments, although the increased pressure from the collision gas is an offsetting disadvantage. A novel system that uses the same laser for photodesorption of ions and their subsequent photodissociation can produce complete dissociation of larger oligopeptide ions and unusually abundant fragment ions. In comparison to CAD, much more internal energy can be deposited in the primary ions using 193-nm photons, sufficient to dissociate peptide ions of m/z > 2000. Mass spectra closely resembling ion photodissociation spectra can also be obtained by neutral photodissociation (193-nm laser irradiation of the sample) followed by ion photodesorption
Urinary antihypertensive drug metabolite screening using molecular networking coupled to high-resolution mass spectrometry fragmentation
Introduction
Mass spectrometry is the current technique of choice in studying drug metabolism. High-resolution mass spectrometry in combination with MS/MS gas-phase experiments has the potential to contribute to rapid advances in this field. However, the data emerging from such fragmentation spectral files pose challenges to downstream analysis, given their complexity and size.
Objectives
This study aims to detect and visualize antihypertensive drug metabolites in untargeted metabolomics experiments based on the spectral similarity of their fragmentation spectra. Furthermore, spectral clusters of endogenous metabolites were also examined.
Methods
Here we apply a molecular networking approach to seek drugs and their metabolites, in fragmentation spectra from urine derived from a cohort of 26 patients on antihypertensive therapy. The mass spectrometry data was collected on a Thermo Q-Exactive coupled to pHILIC chromatography using data dependent analysis (DDA) MS/MS gas-phase experiments.
Results
In total, 165 separate drug metabolites were found and structurally annotated (17 by spectral matching and 122 by classification based on a clustered fragmentation pattern). The clusters could be traced to 13 drugs including the known antihypertensives verapamil, losartan and amlodipine. The molecular networking approach also generated clusters of endogenous metabolites, including carnitine derivatives, and conjugates containing glutamine, glutamate and trigonelline.
Conclusions
The approach offers unprecedented capability in the untargeted identification of drugs and their metabolites at the population level and has great potential to contribute to understanding stratified responses to drugs where differences in drug metabolism may determine treatment outcome
Correlations of chemical mass shifts of para-substituted acetophenones and benzophenones with brown’s σp+ constants
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