Publications by authors named "K Buchmann"

211 Publications

Control of parasitic diseases in aquaculture.

Authors:
Kurt Buchmann

Parasitology 2022 Aug 11:1-50. Epub 2022 Aug 11.

Laboratory of Aquatic Pathobiology, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen,Frederiksberg C., Denmark.

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http://dx.doi.org/10.1017/S0031182022001093DOI Listing
August 2022

Introduced European bison () in a confined forest district: A ten year parasitological survey.

Int J Parasitol Parasites Wildl 2022 Aug 21;18:292-299. Epub 2022 Jul 21.

Section of Parasitology and Aquatic Pathobiology, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C., Denmark.

In the year 2012 a total of seven individuals (one bull and six cows) of European bison () were introduced to a fenced 200 ha area in a forest district (Almindingen, Island Bornholm, Denmark) in the Baltic Sea. In 2017 the herd was supplemented by introduction of another bull. The animals all originated from a population in the Polish Bialowieza forest. Faecal samples were recovered with intervals and subjected to a copro-parasitological investigation (applying egg flotation, sedimentation and Baermann technique). In addition, parasites were sampled during necropsy of animals euthanized or found dead three years after introduction. The animals carried a range of parasite types including trematodes (liver fluke and rumen fluke), cestodes (), nematodes ( trichurids and other gastrointestinal nematodes (GIN) including and ). Egg and larval morphology also suggested presence of GIN genera and The trematodes did not establish a life cycle in the recipient area, as judged by examination of calves born in the new area, but the cestode and several nematode species occurred in these animals. Especially was successfully spread and occurred together with GIN at moderate to high infection intensities at most sampling points. The reproduction among bison in the herd was high during the first few years. The exact birth rate is unknown but up to 24 calves are believed to be born during the ten year study period. Mortality among adults and calves occurred and in early June 2022 the total number of live animals was 11 (seven males, three females, one calf). The possible impact of the parasite infections on the bison health and future wildlife infection status is discussed.
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http://dx.doi.org/10.1016/j.ijppaw.2022.07.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9350870PMC
August 2022

Small, charged proteins in salmon louse (Lepeophtheirus salmonis) secretions modulate Atlantic salmon (Salmo salar) immune responses and coagulation.

Sci Rep 2022 05 14;12(1):7995. Epub 2022 May 14.

Department of Biological Sciences, SLRC-Sea Lice Research Centre, University of Bergen, Pb. 7803, 5020, Bergen, Norway.

Little is known about glandular proteins secreted from the skin- and blood-feeding ectoparasite salmon louse (Lepeophtheirus salmonis). The labial gland has ducts extending into the oral cavity of the lice, and the present study aimed to identify novel genes expressed by this gland type and to investigate their role in modulation of host parameters at the lice feeding site. Five genes associated with labial gland function were identified and named Lepeophteirus salmonis labial gland protein (LsLGP) 1-4 and 1 like (LsLGP1L). All LsLGPs were predicted to be small charged secreted proteins not encoding any known protein domains. Functional studies revealed that LsLGP1 and/or LsLGP1L regulated the expression of other labial gland genes. Immune dampening functions were indicated for LsLGP2 and 3. Whereas LsLGP2 was expressed throughout the parasitic life cycle and found to dampen inflammatory cytokines, LsLGP3 displayed an increased expression in mobile stages and appeared to dampen adaptive immune responses. Expression of LsLGP4 coincided with moulting to the mobile pre-adult I stage where hematophagous feeding is initiated, and synthetic LsLGP4 decreased the clotting time of Atlantic salmon plasma. Results from the present study confirm that the salmon louse secretes immune modulating and anti-coagulative proteins with a potential application in new immune based anti-salmon louse treatments.
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http://dx.doi.org/10.1038/s41598-022-11773-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9107468PMC
May 2022

Neutrophils and aquatic pathogens.

Authors:
Kurt Buchmann

Parasite Immunol 2022 06 22;44(6):e12915. Epub 2022 Mar 22.

Laboratory of Aquatic Pathobiology, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

Introduction: Neutrophilic granulocytes are short-lived cells continuously circulating in the vascular system of vertebrates. They play a basic and decisive role in the innate immune defence of the hosts against all types of pathogenic microorganisms.

Methods: Based on a literature study, the functions of neutrophils and cells with similar functions are described. The study places special emphasis on organisms in the aquatic environment and the pathogens occurring in that particular environment.

Results: The evolutionary origin of this specific cell type is not clear, but its most basic traits (recognition of foreign elements, extracellular trap release, phagocytosis and elimination of ingested material) are found in phagocytes in members of evolutionary ancient invertebrate groups spanning from amoebae, sponges, sea-anemones, mollusks (snails and mussels), arthropods (crustaceans and insects) to echinoderms (sea stars and sea urchins). Their functions as innate immune sentinels and effector cells in these groups are well described. Neutrophilic granulocytes with elongated and lobed nuclei (possibly allowing cell movements through narrow extracellular spaces and leaving space for phagosomes) occur in vertebrates including fish, amphibians, reptiles, birds and mammals although the morphology of the nucleus, stainability of cytoplasmic granula, and the antimicrobial armament vary among groups. Following the pathogen invasion of a fish host, the neutrophils migrates from the vascular system into the infection focus. They apply their PRRs (including TLRs) to recognize the invader as non-self, produce netosis by casting extracellular chromatin containing traps in the microenvironment. These nets assist the immobilization of invading microbes and prevents their further spread. The cells attach to and engulf the microbes by phagocytosis, whereafter they eliminate the pathogen in phagolysosomes equipped with a range of killing mechanisms and attract, by release of chemokines, additional immune cells (monocytes, macrophages and lymphocytes) to the site of invasion. Their role in innate immunity of fish hosts towards aquatic pathogens has been elucidated by in vivo and in vitro studies. Neutrophils interact with virus (e.g. IPNV and VHSV), bacteria (e.g. Aeromonas, Vibrio, Edwardsiella, Mycobacterium and Renibacterium) and parasites, including monogeneans (Gyrodactylus), cestodes (Diphyllobothrium), trematodes (Diplostomum) and ciliates (Ichthyophthirius and Philasterides). Despite the decisive function of neutrophils in innate immunity and early protection, the excessive production of ROS, RNS and NETs may lead to pathological disturbances in the host, which are exacerbated if the pathogens evolve immune evasion mechanisms.

Conclusion: Neutrophils in aquatic organisms play a central role in innate immunity but may serve as a toll and a support in acquired protection. The strong impact of the cellular reactions not only on pathogen but also on host tissues emphasizes that an optimal immune reaction is balanced, involves targeted and specific effector mechanisms, which leaves a minimum of collateral damage in host organs.
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http://dx.doi.org/10.1111/pim.12915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9285616PMC
June 2022

Toxicity of the antiparasitic lipopeptide biosurfactant SPH6 to green algae, cyanobacteria, crustaceans and zebrafish.

Aquat Toxicol 2022 Feb 30;243:106072. Epub 2021 Dec 30.

Laboratory of Aquatic Pathobiology, Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark. Electronic address:

A lipopeptide with biosurfactant properties produced by the bacterium Pseudomonas H6 (SPH6) has antiparasitic effects and may serve as an alternative to chemotherapeutants against aquatic pathogens in aquaculture. We have elucidated its ecotoxicological potential by short-term standardized tests, including a growth rate inhibition test with algae (Raphidocelis subcapitata), a lethality test on the cyanobacteria Phormidium autumnale, a lethality test using crustaceans (Daphnia magna), a fish embryo acute toxicity test and a fish acute toxicity test using zebrafish (Danio rerio). The decrease of the biosurfactant concentration in zebrafish test water during 24 h was measured. The toxicity for crustaceans was highest (LC = 20 mg/L), followed by the test with the zebrafish embryo (LC = 27 mg/L). The juvenile zebrafish fish (complete mortality occurred between 40 and 80 mg/L), the cyanobacteria (LC = 80 mg/L) and the green algae (EC = 170 mg/L) showed higher tolerance. The determination of SPH6 concentrations in fish tank (up to 50% elimination over 24 h) suggested that the compound may become adsorbed to tank walls, absorbed by fish or degraded. Further studies should determine its impact under different environmental settings (e.g. temperature) relevant for different branches of the aquaculture sector.
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http://dx.doi.org/10.1016/j.aquatox.2021.106072DOI Listing
February 2022
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