Thammatorn and colleagues 2024

Thammatorn W, Kouba A, Nováková P, Žlábek V, Koubová A. 2024. Effects of diphenhydramine on crayfish cytochrome P450 activity and antioxidant defence mechanisms: First evidence of CYP2C- and CYP3A-like activity in marbled crayfish. Ecotoxicology and Environmental Safety 285: 117035. https://doi.org/10.1016/j.ecoenv.2024.117035

Abstract

Growing evidence has reported that diphenhydramine (DPH), an ionisable antihistamine, is widely present in surface waters across the world. Relative to vertebrates studied, its impact on invertebrates, particularly concerning cytochrome P450 (CYP) metabolism and oxidative stress, remains poorly understood. In this study, we aimed to investigate the effects of 2, 20, and 200 µg/L DPH on marbled crayfish (Procambarus virginalis) after 96-h exposure. Specifically, we assessed CYP activity, antioxidant enzyme responses, and acetylcholinesterase (AChE) activity in gills, muscle, and hepatopancreas. The crayfish CYP metabolised fluorogenic CYP-metabolic substrates of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) and dibenzylfluorescein (DBF), which evidenced the activity of CYP2C and CYP3A isoforms, well known in mammalian detoxification metabolism. Both BFC and DBF dealkylations showed a positive correlation with each other but were negatively correlated to water and haemolymph DPH concentrations. Exposure to 200 µg/L DPH elicited an apparent inhibition trend, albeit not significant, in BFC- and DBF-transformation activities in crayfish. Other tested 7-benzyloxyresorufin and 7-pentoxyresorufin substrates were poorly metabolised, suggesting their relatively low activity or the lack of mammalian-like CYP1A and CYP2B isoforms in marbled crayfish. The significant modulation of antioxidant enzymes was demonstrated in gills and hepatopancreas. The exposure to DPH did not alter the activity of AChE. Integrated biomarker response version 2 showed the highest cumulative effect of DPH exposure on gills, implying that gill tissue is the most reliable matrix for evaluating DPH toxicity. Activities of glutathione peroxidase and glutathione-S-transferase were the most deviated determinants among the investigated biomarkers, providing insights into the DPH toxicity in crayfish. This study brought the first insight into utilising the fluorogenically active substrates BFC and DBF to demonstrate the CYP involvement in the detoxification metabolism in marbled crayfish. Further, our results provided information on valuable antioxidant defence mechanisms and biomarker responses for a future DPH toxicity assessment in aquatic organisms.

 

Keywords: cytochrome P450 • oxidative stress • biomarker • aquatic invertebrate • antihistamine 

 

 

Marmorkrebs in Tanzania?

My usual Google alerts for marbled crayfish are usually misses, but this immediately caught my eye:

 

 

Transcript:

 

What if I told you a crayfish could clone itself and feed a nation? Welcome to the marbled crayfish saga.

 

Back in 1995 a reproductive accident in an aquarium created the marbled crayfish, a
freshwater Houdini that can clone itself. (That year is the first unambiguous record, not when the species originated, which was probably some time before that. And the origin may not have been an “accident in an aquarium.” This is unknowable. - ZF)

 

Sounds like sci-fi, right? This little critter with its army of identical offspring spread rapidly across continent in Tanzania where protein sources can be scarce and expensive. This invasive species turned into an unexpected hero. Locals quickly figured out that the marbled crayfish is not just easy to catch but also packed with nutrients. Talk about turning lemons into lemonade.

 

So from an accidental aquarium escapade to a cheap protein source for Tanzanians, the marbled crayfish is redefining what it means to be an invasive species. Nature enthusiasts, keep an eye out. This crayfish is making waves, one clone at a time.

 

If so, this would be the first record of marbled crayfish in Tanzania. But several things about this video make me skeptical.

 

The video has no references, so the source of this information is unknown. The last big review of crayfish introductions in Africa (Madzivanzira et al. 2020) makes only only mention of Tanzania:

 

(A)necdotal records suggest that P. clarkii may have established in the Kagera River, which enters Lake Victoria on the Uganda–Tanzania border.

 

I find it hard to believe that marbled crayfish are so widespread in Tanzania that there is no record in the scientific literature or anywhere else that I can find. (A Google search first brings up pictures of Tasmanian crayfish, so sure is the search engine that I must have meant Australia and not Africa.) It sounds like Tanzania has maybe been confused with Madagascar, where marbled crayfish are well established.

 

This crayfish clips show many species that are almost certainly not marbled crayfish. Only the very first shot seems to be marbled crayfish; the remainder seem to be Louisiana red swamp crayfish (Procambarus clarkii) and some other north American species (maybe Orconectes rusticus?).

 

Finally, the video implies, “How big a problem is it really if people can eat them?” I hate that this implies that we don’t have to take invasive species seriously.

Edit, 13 September 2024: The creator admitted this was suppressed to be Madagascar, not Tanzania. There’s a new video with the correct country.

References

Madzivanzira TC, South J, Wood LE, Nunes AL, Weyl OLF. 2020. A review of freshwater crayfish introductions in Africa. Reviews in Fisheries Science & Aquaculture 29(2): 218-241. https://doi.org/10.1080/23308249.2020.1802405

External links

Marbled Crayfish: From Aquarium Accident to Tanzania's Protein Powerhouse!

Related posts

Why people can’t take invasive crayfish seriously

Marmorkrebs featured in Indian news article

India Today has a nice little feature on animals that reproduce asexually. I am a little disappointed that marbled crayfish only come in at the middle of the list, but the photo they used is nice.

External links

7 animals that reproduce without mating

Musil and colleagues 2024

Musil M, Let M, Riebel M, Balzani P, Kouba A. 2024. Non-native three-spined stickleback, a small but voracious predator of invasive crayfish. Journal of Vertebrate Biology 73: 24060. https://doi.org/10.25225/jvb.24060

Abstract

Numerous fish and crayfish species are invasive in freshwater ecosystems, where they interact. In this study, we performed two experiments to investigate adult three-spined stickleback Gasterosteus aculeatus predation on early juvenile invasive crayfish in Europe. The first experiment focused on evaluating predation upon early juveniles of three invasive species (the marbled crayfish Procambarus virginalis, the spiny-cheek crayfish Faxonius limosus, and the signal crayfish Pacifastacus leniusculus) with varying exposure times (one, three and six hours), revealing crayfish species-specific vulnerabilities and the role of exposure duration. Marbled and spiny-cheek crayfish juveniles were more susceptible to three-spined stickleback predation than signal crayfish. Nevertheless, larger signal crayfish suffered more damage caused by the fish predator. The second experiment assessed the role of size in predation efficiency, using three different size groups of marbled crayfish juveniles as prey of adult three-spined sticklebacks during three hours of exposure. In this second experiment, we found the predation level to be size-dependent, with the smallest group of juveniles (20-80 mg) being preyed upon the most, and the largest group (250-350 mg) the least. The efficient predation of the three-spined stickleback on large juvenile crayfish underscores its potential ecological impacts also on native crayfish.

Keywords: behavioural ecology • biological invasion • non-native crayfish • non-native fish • predation

Boštjančić and colleagues 2022

Boštjančić LL, Francesconi C, Rutz C, Hoffbeck L, Poidevin L, Kress A, Jussila J, Makkonen J, Feldmeyer B, Bálint M, Schwenk K, Lecompte O, Theissinger K. 2022. Dataset of the de novo assembly and annotation of the marbled crayfish and the noble crayfish hepatopancreas transcriptomes. BMC Research Notes 15(1): 281. https://doi.org/10.1186/s13104-022-06137-6

Abstract

Objectives

Crayfish plague disease, caused by the oomycete pathogen Aphanomyces astaci represents one of the greatest risks for the biodiversity of the freshwater crayfish. This data article covers the de novo transcriptome assembly and annotation data of the noble crayfish and the marbled crayfish challenged with Ap. astaci. Following the controlled infection experiment (Francesconi et al. in Front Ecol Evol, 2021, https://doi.org/10.3389/fevo.2021.647037), we conducted a differential gene expression analysis described in (Boštjančić et al. in BMC Genom, 2022, https://doi.org/10.1186/s12864-022-08571-z)

Data description

In total, 25 noble crayfish and 30 marbled crayfish were selected. Hepatopancreas tissue was isolated, followed by RNA sequencing using the Illumina NovaSeq 6000 platform. Raw data was checked for quality with FastQC, adapter and quality trimming were conducted using Trimmomatic followed by de novo assembly with Trinity. Assembly quality was assessed with BUSCO, at 93.30% and 93.98% completeness for the noble crayfish and the marbled crayfish, respectively. Transcripts were annotated using the Dammit! pipeline and assigned to KEGG pathways. Respective transcriptome and raw datasets may be reused as the reference transcriptome assemblies for future expression studies.

 

Keywords: freshwater crayfish • Astacus astacus • Procambarus virginalis • crayfish plague • RNA sequencing

Toutain and colleagues 2024

Toutain M, Soto I, Oficialdegui FJ, Balzani P, Cuthbert RN, Haubrock PJ, Kouba A. 2024. Ecological importance of crayfish claws in consumption of mobile benthic prey. Aquatic Sciences 86(4): 103. https://doi.org/10.1007/s00027-024-01107-5

Abstract

Trophic interactions are a critical component of ecosystem stability, governing prey-predator relationships. Crayfish are involved in numerous interactions within freshwater communities and, when non-native, they can negatively impact the structure and dynamics of ecosystems. During biotic interactions or unsuccessful molts, they are able to autotomize one or more claws, which can lead to changes in ecological performance among individuals. Because crayfish claws play an important role in feeding behavior, this creates an overlooked biotic context that could influence trophic interactions and impact on prey communities. It has been shown previously that crayfish claws have a minor role in predation of slow, soft prey, but their function concerning fast hard-bodied prey remains poorly studied. Here, we investigate whether the number of claws on marbled crayfish Procambarus virginalis modulates its ecological impact (focusing on predation rate) using functional response analyses against more mobile hard-bodied prey. We showed that the number of claws in P. virginalis significantly influenced the rate of predation on the prey Gammarus fossarum, with crayfish with two claws exhibiting a higher attack rate and lower handling time than clawless individuals. In addition, we found that non-trophic interactions increased with prey density, with generally antagonistic interactions between crayfish that reduced prey risk irrespective of claw presence. The influence of biotic contexts such as claw presence, prey density and prey type, as well as consumer density, should be considered in inferences of trophic and non-trophic interactions, as well as ecological impacts of invasive species.

 

Keywords: functional response • Procambarus virginalis • Gammarus fossarum • non-trophic interaction strength • competition