Seasonal Bioaccumulation of Heavy Metals by Medicinal Leech Hirudo verbana

2018 ◽  
Vol 54 (5) ◽  
pp. 56-62
Author(s):  
L. V. Chornaya ◽  
L. A. Kovalchuk ◽  
N. V. Mikshevich
2020 ◽  
Vol 17 (168) ◽  
pp. 20200300
Author(s):  
Tim Kampowski ◽  
Lara-Louise Thiemann ◽  
Lukas Kürner ◽  
Thomas Speck ◽  
Simon Poppinga

Haematophagous ectoparasites must ensure a reliable hold to their host during blood meals and, therefore, have evolved a broad spectrum of versatile and effective attachment mechanisms. The Mediterranean medicinal leech ( Hirudo verbana ), for example, uses suction on both smooth and textured air-tight substrates. However, preliminary studies showed that H. verbana is also capable of attaching itself to air-permeable substrates, where suction does not work. Using high-speed videography and mechanical tests, we comparatively investigated the attachment of H. verbana on both smooth and textured air-tight as well as on porous artificial substrates, also considering the influence of mucus on sucker surfaces. In general, the leech-specific locomotion cycle did not differ between the tested surfaces, and the leeches were able to reliably attach to both air-tight and porous substrates. From our results, we conclude that suction is presumably the primary attachment mechanism of H. verbana . However, secondary mechanisms such as mechanical interlocking with surface asperities and pores or capillary forces occurring at the interface between the mucus-covered suckers and the substratum are also employed. In any case, the rich repertoire of applicable attachment principles renders the organs of H. verbana functionally highly resilient.


2016 ◽  
Vol 13 (117) ◽  
pp. 20160096 ◽  
Author(s):  
Tim Kampowski ◽  
Laura Eberhard ◽  
Friederike Gallenmüller ◽  
Thomas Speck ◽  
Simon Poppinga

Medicinal leeches use their suction discs for locomotion, adhesion to the host and, in the case of the anterior disc, also for blood ingestion. The biomechanics of their suction-based adhesion systems has been little understood until now. We investigated the functional morphology of the anterior and posterior suckers of Hirudo verbana by using light and scanning electron microscopy. Furthermore, we analysed the adhesion qualitatively and quantitatively by conducting behavioural and mechanical experiments. Our high-speed video analyses provide new insights into the attachment and detachment processes and we present a detailed description of the leech locomotion cycle. Pull-off force measurements of the anterior and posterior suction organs on seven different substrates under both aerial and water-submersed conditions reveal a significant influence of the surrounding medium, the substrate surface roughness and the tested organ on attachment forces and tenacities.


2017 ◽  
Author(s):  
Andrew M. Lehmkuhl ◽  
Arunkumar Muthusamy ◽  
Daniel A. Wagenaar

Summary statementCues from water movement help aquatic predators find their prey. We study how the nervous system of the medicinal leech processes visual and mechanical information derived from surface waves.AbstractSensitivity to water waves is a key modality by which aquatic predators can detect and localize their prey. For one such predator, the medicinal leech, Hirudo verbana, behavioral responses to visual and mechanical cues from water waves are well documented. Here, we quantitatively characterized the response patterns of a multisensory interneuron, the S cell, to mechanically and visually cued water waves. The frequency dependence of the S-cell response matched the behavioral response well, in that sensitivity was higher for low frequencies in the visual modality and for high frequencies in the mechanical modality. We demonstrated that neither the cephalic ganglia nor the tail brain is required for the S cell to respond to visually cued water waves. The direction of spike propagation within the S- cell system did follow the direction of wave propagation under certain circumstances, but it is unlikely that downstream neuronal targets can use this information. In terms of overall firing rate, the S cell response was not direction selective. Accordingly we propose a role for the S cell in the detection of waves but not in the localization of their source.


2020 ◽  
Vol 37 (3) ◽  
pp. 207-211
Author(s):  
Bahadır Ugural ◽  
Ramazan Serezli

Breeding medicinal leeches in controlled environments is extremely important in order to prevent their extinction. Moreover, due to medicinal leeches coming into contact with the patient's blood, breeding medicinal leeches in hygienic conditions is essential to prevent possible complications. In this study, breeding patterns of Hirudo verbana were studied in controlled conditions and the effects of various moist environments were examined. Peat, hydrogel and chopped sponge materials were compared in terms of number of cocoon and offspring in medicinal leech breeding. Peat and hydrogel environments didn’t show any statistically significant difference for number of cocoon and offspring breeding. Cocoon per leech was 3.13 ± 0.74 for peat and 2.80 ± 0.56 for hydrogel respectively. Offspring per cocoon was 11.81 ± 2.27 for peat and 12.52 ± 1.98 for hydrogel (P>0.05) respectively. In conclusion, hydrogel could be a new material for medicinal leech cocoon deposition environment especially for laboratory breeders.


2019 ◽  
Author(s):  
Emily Ann McClure ◽  
Michael C. Nelson ◽  
Amy Lin ◽  
Joerg Graf

ABSTRACTLeeches are found in terrestrial, aquatic, and marine habitats on all continents. Sanguivorous leeches have been used in medicine for millennia. Modern scientific uses include studies of neurons, anticoagulants, and gut microbial symbioses.Hirudo verbana, the European medicinal leech, maintains a gut community dominated by two bacterial symbionts,Aeromonas veroniiandMucinivorans hirudinis, which sometimes account for as much as 97% of the total crop microbiota. The highly simplified gut anatomy and microbiome ofH. verbanamake it an excellent model organism for studying gut microbial dynamics. The North American medicinal leech,Macrobdella decora,is a hirudinid leech native to Canada and the northern U.S.A. In this study we show thatM. decorasymbiont communities are very similar to those inH. verbana.This similarity allowed for an extensive study in which wild caught animals were sampled to determine effects of geographic separation, time of collection, and feeding on the microbiome. Through 16S V4 rRNA deep sequencing we show that: i) theM. decoragut and bladder microbial communities are distinct, ii) theM. decoragut community is affected by feeding and long periods of starvation, and iii) geographic separation does not appear to affect the overall gut microbial community structure. We propose thatM. decorais a replacement forH. verbanafor studies of wild-caught animals and offer evidence for the conservation of annelid symbionts. Successful culturing and comparison of dominant symbionts fromM. decoraandH. verbenawill provide the ability to assess host-symbiont co-evolution in future work.IMPORTANCEBuilding evidence implicates the gut microbiome in regulating animal digestion, nutritional acquisition, immune regulation, development, and even mood regulation. Because of the difficulty of assigning causative relationships in complex gut microbiomes a simplified model for testing hypotheses is necessary. Previous research inHirudo verbanahas suggested this animal as a highly simplified and tractable animal model of gut symbioses. Our data show thatMacrobdella decoramay work just as well asH. verbanawithout the drawback of being an endangered organism and with the added convenience of easy access to field-caught specimens. The similarity of the microbial community structure of species from two different continents reveals the highly-conserved nature of the microbial symbionts in sanguivorous leeches and confirms the medicinal leech as a highly simplified, natural animal model in which to study gut symbioses.


2020 ◽  
Author(s):  
Riley T. Paulsen ◽  
Diing D.M. Agany ◽  
Jason Petersen ◽  
Christel M. Davis ◽  
Erik A. Ehli ◽  
...  

The medicinal leech, Hirudo verbana, is a powerful model organism for investigating fundamental neurobehavioral processes. The well-documented arrangement and properties of H. verbana’s nervous system allows changes at the level of specific neurons or synapses to be linked to physiological and behavioral phenomena. Juxtaposed to the extensive knowledge of H. verbana’s nervous system is a limited, but recently expanding, portfolio of molecular and multi-omics tools. Together, the advancement of genetic databases for H. verbana will complement existing pharmacological and electrophysiological data by affording targeted manipulation and analysis of gene expression in neural pathways of interest. Here, we present the first draft genome assembly for H. verbana, which is approximately 250 Mbp in size and consists of 61,282 contigs. Whole genome sequencing was conducted using an Illumina sequencing platform followed by genome assembly with CLC-Bio Genomics Workbench and subsequent functional annotation. Ultimately, the diversity of organisms for which we have genomic information should parallel the availability of next generation sequencing technologies to widen the comparative approach to understand the involvement and discovery of genes in evolutionarily conserved processes. Results of this work hope to facilitate comparative studies with H. verbana and provide the foundation for future, more complete, genome assemblies of the leech.


2008 ◽  
Vol 74 (19) ◽  
pp. 6151-6154 ◽  
Author(s):  
Alison S. Laufer ◽  
Mark E. Siddall ◽  
Joerg Graf

ABSTRACT FDA-approved, postoperative use of leeches can lead to bacterial infections. In this study, we used culture-dependent and culture-independent approaches to characterize the digestive-tract microbiota of Hirudo orientalis. Surprisingly, two Aeromonas species, A. veronii and A. jandaei, were cultured. Uncultured Rikenella-like bacteria were most similar to isolates from Hirudo verbana.


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