13 July 2023

Arianoutsou and colleagues 2023

Arianoutsou M, Adamopoulou C, Andriopoulos P, Bazos I, Christopoulou A, Galanidis A, Kalogianni E, Karachle PK, Kokkoris Y, Martinou AF, Zenetos A, Zikos A. 2023. HELLAS-ALIENS. The invasive alien species of Greece: time trends, origin and pathways. NeoBiota 86: 45-79. https://doi.org/10.3897/neobiota.86.101778


The current paper presents the first effort to organize a comprehensive review of the Invasive Alien Species (IAS) of Greece. For this purpose, a database was developed with fields of information on the taxonomy, origin, ecology and pathways of introduction of terrestrial, freshwater and marine species. Our database includes a) taxa in the Union’s list that are present in Greece, b) taxa already present in Greece and considered to be invasive, and c) taxa highly likely to enter Greece in the next 10 years and become invasive. The Database served as the starting point for the compilation of the National List of Alien Invasive Species (HELLAS-ALIENS) in compliance with the EU Regulation 1143/2014. Overall, the HELLAS-ALIENS comprises 126 species, i.e. 32 terrestrial and freshwater plant species, 14 terrestrial invertebrates, 28 terrestrial vertebrates, 30 freshwater fishes and invertebrates and 22 marine species. Terrestrial invertebrates, birds and mammals are mainly of Asiatic origin. Most of the terrestrial plants have their native geographical distribution in the Americas (North and South). Most of the freshwater invertebrates and fishes are of North American origin, while the majority of the marine species are of Indo-Pacific origin. The first records of IAS concern terrestrial plant species, and date back to the 19th century, while those in freshwater and marine ecosystems seem to have been systematically recorded some decades later. Regarding the pathways of introduction, most of the taxa arrived in Greece or are expected to arrive through escape from confinement and unaided. The majority of the terrestrial, freshwater and marine species have been evaluated as of High-risk for the indigenous biodiversity and only 3% of the species listed have been evaluated of Low-risk. Our results provide an important baseline for management and action plans, as required by the priorities set by the European Union through the Biodiversity Strategy for 2030.


Keywords: European Union • Invasive Alien Species Regulation • pathways of introduction • risk assessments • temporal trends


(Note: Marmorkrebs are listed as “Taxa not currently present in Greece but highly likely to be introduced within the next 10 years.”)

Open access

12 July 2023

Roy 2023

Illinois State University logo.
Roy RS. 2023. Identification of gap junction genes involved in the tail-flip escape circuit of marbled crayfish. MSc thesis, Illinois State University. Illinois State University ProQuest Dissertations Publishing. 30313359. https://www.proquest.com/openview/0976de027582da67e16ba85b62d594dc/1


Escape responses are highly stereotyped behaviors that enable organisms to avoid threats in their environment. To ensure the rapid and robust execution of these behaviors, they are often mediated by dedicated neuronal circuits with fast feed-forward signal propagation. Rectifying electrical synapses, which allow electrical current to preferentially flow only in one direction, are a hallmark of such circuits, and facilitate rapid and stereotyped neuronal signaling for fast, reflexive behaviors. In vitro studies have suggested that it is the heterotypic distribution of the gap junction proteins (called innexins in invertebrates), i.e., possessing different innexins in pre- and postsynaptic neurons, that enables the rectification of the electrical synapse. However, the presence of distinct pre- and postsynaptic gap junction proteins and the functional roles of these proteins have not been established in escape circuits. I am using the tail-flip escape behavior of crayfish, a classical behavioral model for understanding escape responses, to study gap junction proteins. The neuronal circuitry of the crayfish tail-flip behavior has been largely worked out, with specialized giant neurons identified for the two major types of escape modes in the animal – the lateral giant (LG) and medial giant (MG) tail-flip. In both MG and LG escape circuits, rectifying electrical synapses facilitate rapid signal transmission from primary afferents to the
motor neurons. However, the innexin proteins expressed in the crayfish nervous system and contributing to these rectifying synapses are unknown. To address this gap in knowledge, I use the marbled crayfish (Procambarus virginalis), the only crayfish species with identified genome and transcriptome. Employing bioinformatics, I identified five putative innexin genes (named Inx1 - Inx5), four of which were expressed in the nervous system and likely contribute to tail flip escape responses. Four of the five putative innexins (Inx2 – 5) were expressed in the ventral nerve cord and three of them (Inx2, 3 and 5) were also expressed in the brain. To test the contribution of these innexins to the escape behavior, I used RNA interference to reduce innexin expression. This was followed by behavioral assays to test whether MG and LG tail flips were altered by the RNAi treatment. My results indicate that reduction in expression of two of the five identified innexins, i.e., Inx2 and Inx3, using RNAi resulted in a significant delay in the onset of the LG tail-flip. This suggests that these two innexin proteins contribute to the formation of gap junction channels in the LG tail-flip circuit. In contrast, no significant effect was found for the MG tail-flip following the same RNAi approach. From these results, I conclude that there are four innexin proteins that are expressed in marbled crayfish nervous system and are homologousto other invertebrate innexins. Moreover, marbled crayfish innexin 2 and 3 constitute the gap junction channels that form electrical synapses in the LG tail-flip circuit and are important for robust signal transmission.

Keywords: electrical synapses • giant neurons • gap junctions • innexins • escape response •
tail-flip • RNA interference

Vogt 2023b

Cover to "Epigenetics in Aquaculture"

Vogt G. 2023. Epigenetics in Crustaceans. In: Piferrer F, Wang H-P (eds.), Epigenetics in Aquaculture, pp. 355-381. https://doi.org/10.1002/9781119821946.ch16


This chapter summarizes research on epigenetics in crustaceans and outlines possible applications in crustacean aquaculture. Information on epigenetic mechanisms and their role in gene and phenotype expression, development, ecology, and evolution is mainly available for brine shrimps and water fleas that are cultured as live feed for fish and shellfish larviculture, and for representatives of shrimps, crayfish, and crabs that are cultured for human consumption. The best-investigated crustaceans, with respect to epigenetics, are parthenogenetic lineages of Artemia brine shrimps and Daphnia water fleas and the obligatory parthenogenetic crayfish Procambarus virginalis. Most of the work has been done on DNA methylation followed by histone modifications. The topics studied cover the involvement of epigenetic mechanisms in gene regulation, tissue differentiation, phenotypic variation, development, growth, reproduction, aging, environmental adaptation, resistance to toxicants and pathogens, training of immunity, sex determination, transgenerational inheritance of acquired characters, and speciation. The knowledge gathered has not yet been applied in crustacean aquaculture, but the data suggest that epigenetic interventions have good potential to improve the growth and reproduction of cultured species, manipulate sex, and increase resistance to environmental stressors and diseases.

05 July 2023

Artem and colleagues, 2023

Logo for World Scientific News
Artem O, Oleh M, Iryna H. 2023.  Physiological and biochemical adaptations’ assessment of the marbled crayfish Procambarus virginalis (Lyko, 2017) as an invasive specie (sic) of Ukraine. World Scientific News 182: 57-76. http://www.worldscientificnews.com/article-in-press/2023-2/182-2023/http://www.worldscientificnews.com/wp-content/uploads/2023/06/WSN-182-2023-57-76.pdf (direct link to PDF)


Marbled crayfish are the typical invasive hydrobionts spreaded over the lot of world`s waterbodies and create the populations that can reproduce in the presence of only one triploid female, thereby the threat of biodiversity appears and increase the competition with local species. Due to the appearance of the marbled crayfish Procambarus virginalis (Lyko, 2017) in the open Ukrainian waterbodies, there is necessity to research it`s adaptation possibilities to the ecological factors to predict it`s possible spread and naturalization. The research aim was to determine the physiological and biochemical features of the adaptations of marbled crayfish as a new species inhabiting the aquatic ecosystems of Ukraine under the conditions of toxicological load on the aquatic ecosystem. The obtained research results indicate significant changes in individual cytological and biochemical indicators of marbled crayfish under the impact of heavy metal ions. A change in these parameters may indicate a rapid cellular response of the crustacean species to the toxic effect of heavy metals. These indicators can be used in the future in studying the adaptation of marbled crayfish in natural waterbodies.

Keywords: heavy metals • marble crayfish • physiology • adaptation

Logo for open access

01 July 2023

Roy and collegues 2023

"Food Chemistry" journal cover
Roy K, Das K, Petraskova E, Kouba A. 2023. Protein from whole-body crayfish homogenate may be a high supplier of leucine or branched-chain amino acids – A call for validation on genus Procambarus sp. Food Chemistry 427: 136728. https://doi.org/10.1016/j.foodchem.2023.136728


Essential proteinogenic branched-chain amino acids (BCAA), particularly leucine (Leu) have been investigated for their role in enhancing human myofibrillar protein synthesis and biomedical research on tumor models. However, only a few protein sources in our current foor system have high enough BCAA or Leu coefficients (% of total amino acids) to be considered as supplements for food, sport, or biomedical research. Mostly dairy-sourced proteins such as casein and whey or rarely plant source such as maize gluten are typically regarded as the gold standards. This study hypothesized that protein isolates derived from the whole-body homogenate (including the chitinous exoskeleton) of procambarid crayfish might exhibit unusually high BCAA and Leu content. The study provides open-access data on the amino acid compositions of two procambarid crayfish (Procambarus virginalis and P. clarkii), as well as a comparison with casein. The mentioned crayfish species could offer 6.36–7.39 g Leu 100 g−1 dry matter (at 43–48% protein only). Crayfish whole-body protein isolates exhibit a Leu coefficient (18.41±2.51% of total amino acids) and a BCAA coefficient (28.76±2.39% of total amino acids), which is comparable to or higher than of casein (Leu coefficient 8.65±0.08%; BCAA coefficient 20.03±0.73%). However, it is important to interpret these results with caution, due to the challenges associated with leucine and isoleucine separation, as well as potential interactions within the sample matrices. Hence, international validation of these findings is recommended.


Keywords: crayfish protein • human muscle protein synthesis • leucine isoleucine valine • amino acids