1,720,975 research outputs found
Diversity of fish parasites in a South Carolina estuary - interesting infection patterns and taxonomic hurdles
No full textIn April and May of 2023, sampling of fish parasite fauna was conducted in the Stono River estuary, in South Carolina, USA. The sampling and the following research of collected parasites were done as part of a BioBlitz, which is a project with an aim of recording all living species within a chosen area, such as urban park or nature reserve. In this case, Stono River estuary is protected as a Stono Preserve area because of its history and the biodiversity present. In this study, 125 fish specimens of 12 genera (17 species) were caught and inspected for parasites; members of only six genera (nine species) were infected: Anchoa (A. mitchilli), Fundulus (F. confluentus, F. heteroclitus, F. majalis), Gambusia (G. holbrooki), Gobiosoma (G. bosc), Menidia (Menidia sp.) and Mugil (M. cephalus, M. curema). From these hosts, 130 parasites were collected, and identified based on their morphology and genetic markers (sequences of 28S, 18S and ITS rDNA). The 15 species observed belonged to different lineages of monopisthocotylan flatworms (Fundulotrema, Gyrodactylus, Ligophorus, Salsuginus), polyopisthocotylan flatworms (Metamicrocotyla) and copepods (Bomolochus, Caligus, Ergasilus, Naobranchia). From all screened hosts, species of Ligophorus have the highest mean intensity and prevalence, and Fundulotrema the lowest. Furthermore, M. cephalus harbors the highest parasite species richness (seven), and Anchoa mitchilli and Menidia sp. the lowest (one per each species). Some of the parasites identified present new records for the Atlantic coast of the USA. Sampled parasites show strong patterns of host-specificity and can be found in different habitats within the estuary, such as creeks, small lakes and water reservoirs. This study points to striking lack of molecular data available for North American fish parasites. Greater knowledge of fish parasite diversity in estuaries would help in understanding how parasite diversity is influenced by changing abiotic factors and global climate change
Diversity of fish parasites in a South Carolina estuary - interesting infection patterns and taxonomic hurdles
No full textIn April and May of 2023, sampling of fish parasite fauna was conducted in the Stono River estuary, in South Carolina, USA. The sampling and the following research of collected parasites were done as part of a BioBlitz, which is a project with an aim of recording all living species within a chosen area, such as urban park or nature reserve. In this case, Stono River estuary is protected as a Stono Preserve area because of its history and the biodiversity present. In this study, 125 fish specimens of 12 genera (17 species) were caught and inspected for parasites; members of only six genera (nine species) were infected: Anchoa (A. mitchilli), Fundulus (F. confluentus, F. heteroclitus, F. majalis), Gambusia (G. holbrooki), Gobiosoma (G. bosc), Menidia (Menidia sp.) and Mugil (M. cephalus, M. curema). From these hosts, 130 parasites were collected, and identified based on their morphology and genetic markers (sequences of 28S, 18S and ITS rDNA). The 15 species observed belonged to different lineages of monopisthocotylan flatworms (Fundulotrema, Gyrodactylus, Ligophorus, Salsuginus), polyopisthocotylan flatworms (Metamicrocotyla) and copepods (Bomolochus, Caligus, Ergasilus, Naobranchia). From all screened hosts, species of Ligophorus have the highest mean intensity and prevalence, and Fundulotrema the lowest. Furthermore, M. cephalus harbors the highest parasite species richness (seven), and Anchoa mitchilli and Menidia sp. the lowest (one per each species). Some of the parasites identified present new records for the Atlantic coast of the USA. Sampled parasites show strong patterns of host-specificity and can be found in different habitats within the estuary, such as creeks, small lakes and water reservoirs. This study points to striking lack of molecular data available for North American fish parasites. Greater knowledge of fish parasite diversity in estuaries would help in understanding how parasite diversity is influenced by changing abiotic factors and global climate change
Symbiotic interactions challenged by environmental stress in aquatic transitional habitats
No full textEstuaries present transitional habitats between freshwater and marine ecosystems. They are known for their changing abiotic conditions, influenced by daily and seasonal changes in sea levels, changes in temperature, and river influx. Estuaries are also significantly impacted by climate change, which affects them through changes of sea levels, water temperature, salinity and acidity. These changes will increase the environmental stress experienced by aquatic organisms and their symbiotic communities, which include bacteria and metazoan parasites, and influence their symbiotic relationships. The impact of climate change and environmental stress on aquatic estuarine organisms is underexplored on the level of symbiotic communities. This project is focused on understanding the effects of global climate change on these communities. We will research the diversity present in fish-parasite-microbiome communities on the east coast of the United States of America using the Atlantic mummichog (Fundulus heteroclitus) as a fish host model species; identify mechanisms of stress response to salinity change in fish ectoparasites; describe the genomic landscape of salinity tolerance in a symbiont community; and model the possible direction of change in a symbiont community under the influence of climate change. The project started with the research of ectoparasites of estuarine fishes from South Carolina. Species of Anchoa, Fundulus, Gambusia, Gobiosoma, Menidia and Mugil (n=11) were screened for the presence of ectoparasites. In total, 15 species belonging to different lineages of monopisthocotylan flatworms (Gyrodactylus, Ligophorus, Salsuginus), polyopisthocotylan flatworms (Metamicrocotyla) and copepods (Bomolochus, Caligus, Ergasilus, Naobranchia). From all screened hosts species Ligophorus have the highest mean intensity and prevalence. Furthermore, M. cephalus harbors the highest parasite species richness (seven). Some of the parasites identified present new records for the study area. These parasites show strong patterns of host-specificity and can be found in different habitats within the estuary, such as creeks, small lakes and water reservoirs
Symbiotic interactions challenged by environmental stress in aquatic transitional habitats
No full textEstuaries present transitional habitats between freshwater and marine ecosystems. They are known for their changing abiotic conditions, influenced by daily and seasonal changes in sea levels, changes in temperature, and river influx. Estuaries are also significantly impacted by climate change, which affects them through changes of sea levels, water temperature, salinity and acidity. These changes will increase the environmental stress experienced by aquatic organisms and their symbiotic communities, which include bacteria and metazoan parasites, and influence their symbiotic relationships. The impact of climate change and environmental stress on aquatic estuarine organisms is underexplored on the level of symbiotic communities. This project is focused on understanding the effects of global climate change on these communities. We will research the diversity present in fish-parasite-microbiome communities on the east coast of the United States of America using the Atlantic mummichog (Fundulus heteroclitus) as a fish host model species; identify mechanisms of stress response to salinity change in fish ectoparasites; describe the genomic landscape of salinity tolerance in a symbiont community; and model the possible direction of change in a symbiont community under the influence of climate change. The project started with the research of ectoparasites of estuarine fishes from South Carolina. Species of Anchoa, Fundulus, Gambusia, Gobiosoma, Menidia and Mugil (n=11) were screened for the presence of ectoparasites. In total, 15 species belonging to different lineages of monopisthocotylan flatworms (Gyrodactylus, Ligophorus, Salsuginus), polyopisthocotylan flatworms (Metamicrocotyla) and copepods (Bomolochus, Caligus, Ergasilus, Naobranchia). From all screened hosts species Ligophorus have the highest mean intensity and prevalence. Furthermore, M. cephalus harbors the highest parasite species richness (seven). Some of the parasites identified present new records for the study area. These parasites show strong patterns of host-specificity and can be found in different habitats within the estuary, such as creeks, small lakes and water reservoirs
Novel Ultrastructural Features of Clinostomum cutaneum in Nile tilapia revealed by Scanning Electron Microscopy
No full textThe parasitic trematode Clinostomum presents a huge challenge to freshwater fish species, particularly Nile tilapia (Oreochromis niloticus), which plays a vital role in both aquaculture and wild fisheries. In a parasitological survey of 157 Nile tilapia samples from fish farms in the Upper Tana River Region, Kenya, 17.2% of the samples dissected and screened for parasites were found to be infected with Clinostomum metacercariae, encysted in the buccal cavity, skin and gills. This study used an integrative identification approach that combined traditional morphological techniques with ultrastructural analysis using scanning electron microscopy (SEM) and molecular methods targeting ribosomal regions (ITS1, 5.8S, ITS2, and 28S). The Clinostomum metacercariae were identified both morphologically and molecularly as C. cutaneum and C. phalacrocoracis. SEM revealed some new ultrastructural features specific to C. cutaneum. One of these is an excretory pore surrounded by minute, spiny papillae, a feature which had not been reported in previous studies. Another finding we observed was the presence of an everted cirrus in the metacercariae, a feature seen in the adult stage of C. cutaneum. However, in our samples, the cirrus lacked basal papillae, showing that there is morphological variation between the adult and metacercarial stages. Additionally, the tegumental area around the genital pore was surrounded by dome-shaped papillae. Our findings, therefore, provide new taxonomic features for the metacercariae of C. cutaneum and demonstrate the value of SEM as a complementary tool for more precise parasite identification and species differentiation
Monomyxum ligophori n. sp. in a ParasiteBlitz: monopisthocotylans as myxozoan hosts in South Carolina and monophyly of a cosmopolitan hyperparasitic clade
No full textA ParasiteBlitz event offers a brief, intense opportunity to discover diverse parasite species and to reveal life cycles of heteroxenous parasite taxa. In this study, we describe Monomyxum ligophori n. sp., a hyperparasitic myxozoan (Monomyxidae) proliferating in two dactylogyrid mono-pisthocotylan flatworms (Ligophorus saladensis, Ligophorus mugilinus) infecting mugilid fishes (Mugil cephalus, Mugil curema) on the Atlantic coast of North America. Furthermore, we used DNA barcoding to infer the parasite's complex life cycle, matching its hyperparasitic myxospore stages with actinospore stages infecting the polychaete Streblospio benedicti found in the same locality during the ParasiteBlitz and also reported previously from the same region. Thus we report the first life cycle of a myxozoan that most likely does not require a vertebrate host. Hyperparasitic myxozoans are rare with only five species reported worldwide to infect flat-worms. This study provides more information on the previously discussed host specificity towards monopisthocotylan hosts of these monomyxid myxozoan hyperparasites. Notably, Monomyxum ligophori n. sp. was detected in two out of four gill-infecting parasitic flatworms (being absent in Ligophorus uruguayensis and Metamicrocotyla macracantha) found infecting the same fish individuals during the ParasiteBlitz. Our molecular data and phylogenetic analysis support the previously suggested common origin of Monomyxum species infecting monopistho-cotylan flatworms, and contribute to understanding the life cycle and host interactions of this unique hyperparasitic myxozoan lineage.This work was supported by a DIOS Incentive Fund Project, Hasselt University (M.P.M.V. and N.K., grant number DIOS/OEYLRODE/2022/001, contract number R-12947); the Special Research Fund (BOF) of Hasselt University (M.P.M.V., grant number BOF20TT06, M.T, grant number 23KP05VHOM and N.K., grant number BOF21PD01); the Belgian Federal Science Policy Office (4255-FED-tWIN-G3 program, Prf-2022-049); a DepartmentofCommerceNOAAFederalAward(grantnumberNA22OAR4170114); a Brain Pool programme for outstanding overseas researchers of the National Research Foundation of Korea (grant number 2021H1D3A2A02081767); a Tartar Research Fund, Department of Microbiology, Oregon State University (S.D.A.); and a USFWS award (grant number F22AP01952); infrastructure was funded by EMBRC Belgium– FWO project GOH3817N.
Acknowledgements.
Fellow parasitologists and team members of the ParasiteBlitz namely I. de Buron (College of Charleston), K.M.Hill-Spanik (College of Charleston), S. Georgieva (Bulgarian Academy of Sciences), D.M. Díaz-Morales (University of Duisburg-Essen and Centre for Water and Environmental Research, Essen), M.R. Kendrick (South Carolina Department of Natural Resources, Charleston), W.A. Roumillat (College of Charleston), and G.K.Rothman(CollegeofCharlestonandSouthCarolina DepartmentofNatural Resources, Charleston) are acknowledgedfortheircrucialsupportinretrievaland screening of fish host specimens. The College of Charleston Foundation allowed usage of Stono Preserve. Dr. Matt Rutter (Academic Director of the Stono Preserve Field Station) is thanked for logistical support of the ParasiteBlitz event. Wewouldliketo thank all the people from the College of Charleston involved in the administrative and field support including Dr. Seth Pritchard, Dr. Eric McElroy, Dr. Courtney Murren, Pete Meier, Greg Townsley, Josie Shostak, Reagan Fauser, Maya Mylott, and Haley Anderson. Michelle Taliercio, Graham Wagner, Jordan Parish, Grace Lewis, and Kevin Spanik from the South Carolina Department of Natural Resources in Charleston helped with collection of fis
Novel Ultrastructural Features of Clinostomum cutaneum in Nile tilapia revealed by Scanning Electron Microscopy
No full textThe parasitic trematode Clinostomum presents a huge challenge to freshwater fish species, particularly Nile tilapia (Oreochromis niloticus), which plays a vital role in both aquaculture and wild fisheries. In a parasitological survey of 157 Nile tilapia samples from fish farms in the Upper Tana River Region, Kenya, 17.2% of the samples dissected and screened for parasites were found to be infected with Clinostomum metacercariae, encysted in the buccal cavity, skin and gills. This study used an integrative identification approach that combined traditional morphological techniques with ultrastructural analysis using scanning electron microscopy (SEM) and molecular methods targeting ribosomal regions (ITS1, 5.8S, ITS2, and 28S). The Clinostomum metacercariae were identified both morphologically and molecularly as C. cutaneum and C. phalacrocoracis. SEM revealed some new ultrastructural features specific to C. cutaneum. One of these is an excretory pore surrounded by minute, spiny papillae, a feature which had not been reported in previous studies. Another finding we observed was the presence of an everted cirrus in the metacercariae, a feature seen in the adult stage of C. cutaneum. However, in our samples, the cirrus lacked basal papillae, showing that there is morphological variation between the adult and metacercarial stages. Additionally, the tegumental area around the genital pore was surrounded by dome-shaped papillae. Our findings, therefore, provide new taxonomic features for the metacercariae of C. cutaneum and demonstrate the value of SEM as a complementary tool for more precise parasite identification and species differentiation
Scanning Electron Microscopy Reveals New Ultrastructural Features in Metacercariae of Clinostomum cutaneum (Digenea: Clinostomidae) Infecting Oreochromis niloticus (Actinopterygii: Cichlidae) in Kenya
No full textClinostomum is a genus of parasitic trematodes found worldwide, infecting a wide range of hosts, including freshwater fishes, snails, birds and occasionally humans. In this study, clinostomid metacercariae were collected from Nile tilapia raised in fish farms in the Upper Tana River region, Kenya. The prevalence of infection was 17.2%, with metacercariae infecting the skin, gills and buccal cavity of the fish. Using light microscopy, scanning electron microscopy (SEM) and molecular methods targeting both the ribosomal (ITS1, 5.8S, ITS2) and mitochondrial (COI) regions, the metacercariae were identified as C. cutaneum, C. phalacrocoracis, C. tilapiae and Euclinostomum heterostomum. The three species of Clinostomum have previously been reported to infect fish and piscivorous birds while E. heterostomum is the first report for Kenya. SEM analysis revealed new ultrastructural features of C. cutaneum, including an excretory pore surrounded by minute spiny papillae, an everted cirrus and dome-shaped papillae on the tegumental area around the genital pore. The cirrus lacked basal papillae, showing morphological variation between the adult and metacercarial stages. Our study, therefore, provides new insights into the phenotypic identification of flukes that may be pathogenic to fishes and humans and, therefore, of scientific and practical importance
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
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