International Symposium: Conservation study on crayfish and invasive alien decapod species : case study on species from the Mediterranean region
14 Oct 2023
シンポジウム趣旨：日本甲殻類学会は外国会員と国外からの大会参加も増えて国際化が進んでいる。この動きを加速するために欧州の甲殻類学の専門家による講演を行う。また日本甲殻類学会は研究領域と会員層の多様化も進んでいる。新しい領域である希少な淡水甲殻類保全を一般市民が実践する例を紹介する。
Organizer：Tadashi Kawai
Gastroliths and biomineralization related gene expression in crayfish
Amir Sagi
Department of Life Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel. National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel
Prof. Amir Sagi studies reproduction and growth in commercially important crustaceans to understand sex differentiation and how these animals/organisms grow their exoskeletons. He received The Crustacean Society Excellence Research Award in 2015. He served President of International Society for Invertebrate Reproduction and Development.
His research on sex differentiation has already led to several successful commercial applications creating single-sex populations of crustaceans. Research in this area is important to the food industry, where larger males fetch a premium price, and he is also working towards using crustaceans as biocontrol agents for pests and invasive species. In addition, his work on crustacean exoskeletons can contribute to the development of products for bone substitutes and tooth regeneration.
Abstract: Having a rigid exoskeleton, crustacean growth processes demand a repetitive molting cycle. During the molt cycle crustaceans form their cuticular structures and many crustacean species, such as crayfish, develop functional structures such as gastroliths, in a specific timing, making them ideal structural biology study organisms. Gastroliths are calcium storage organs deposited on either side of the stomach, growing along the molt cycle, and collapsing into the stomach at ecdysis to serve as mineral sources for calcification of the exoskeleton after molting. The formation of such structures involves growth of the organic matrix including chitin and cuticular proteins, and mineral deposition. The process of gastrolith development in crayfish involves the construction of an extracellular chitinous scaffold over which mostly stabilized amorphous calcium carbonate is deposited. These structures involve a wide repertoire of structural and functional proteins including ion transporters. Based on a molt-related transcriptomic library from crayfish, cuticular and gastrolith protein encoding-genes were mined using a multigenic binary patterning approach developed specifically for the study of structural proteins in crustacean cuticle and gastroliths. Several proteins were studied with respect to cuticular structures and ion transport into exoskeletal biomineralization sites of calcium carbonate.
The gastroliths also serve as an indexed tool to monitor crayfish molt cycle through a Molt Mineralization Index (MMI). Using MMI values the molt cycle could be precisely timed and the molecular background behind growth and biomineralization could be studied. This way molt related transcriptomic libraries were constructed and functional genomics tools such as RNA interference (RNAi) and CRISPR applied to discover the function of relevant proteins. RNAi manipulations significantly affected molt cycle outputs suggesting important functions to several cuticular proteins and ion transporters. Precise functional genomic research and applications of genome editing will contribute to further understanding of the physiological background behind the extremely efficient biomineralization processes in crayfish.
Alien Crustacea Decapoda in the Mediterranean Region: Three Case Studies
Gianna Innocenti
University Museum System, Natural History Museum, University of Florence, via Romana 17, 50125 Firenze (FI), Italy
Dr. Gianna Innocenti is a Decapod taxonomist working on marine and freshwater species and habitats. She has a M.Sc. in Natural Science and she is the curator of the Crustaceans and Echinoderms collections of the Zoological Section of the Natural History Museum, Florence University since 1997. She is a specialist of Decapod Crustaceans. She has produced more than 80 papers in peer review journals, 7 book chapters and 1 book.
Abstract: The introduction of non-native species (NNS) is a significant driver of biodiversity change. Some introductions can alter community dynamics, and lead to the displacement or reduction of native species, affecting the overall health and functioning of marine environments, i.e. the disruption of native ecosystems.
Spatial and temporal spread of NNS in the Mediterranean Sea advanced concurrently with successive enlargements of the Suez Canal, with range expansion of Atlantic species, and increases in mean seawater temperatures and in the prevalence, duration and severity of marine heat waves. The invasion poses a challenge for the environmental policies of the Mediterranean countries in terms of commitment towards conservation of biological diversity.
Eighty-eight non-native decapod species have been recorded in the Mediterranean. This presentation will examine the ecological and economic examples impacts of the portunid crabs Callinectes sapidus and Charybdis longicollis, and the percnid Percnon gibbesi.
The red swamp crayfish Procambarus clarkii in Europe
Elena Tricarico
Department of Biology, University of Florence, Italy
Dr. Elena Tricarico is a behavioural ecologist working on aquatic environments. Since her master, she has been dealing with behaviour and biological invasions, and in the last years she is very active in education and dissemination activities with stakeholders and public on these topics. She is used to work in national and international teams with a multidisciplinary approach, having participated in 19 national projects and 24 international projects. She is a lead author of Chapter 2 for the "Thematic assessment of invasive alien species and their control" at worldwide level conducted by IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services). In 2022, she joined the EICAT (Environmental Impact Classification for Alien Taxa) Authority. She has produced more than 124 papers in peer-review journals, 12 book chapters, 2 books, 60 technical reports for national and European projects.
Abstract: The red swamp crayfish Procambarus clarkii has been widely introduced in Europe for aquaculture and ornamental purposes since 1970s, establishing several abundant populations, especially in the southern countries. Italy is, indeed, one of the most affected countries by the species: P. clarkii was introduced in the 1980s and is now present in almost all the 20 Italian regions, main islands included. In Europe and Italy, besides being a vector of crayfish plague, which is responsible for large-scale disappearance of native crayfish species, it causes severe impacts on diverse aquatic ecosystems, due to its rapid life cycle, dispersal capacities, burrowing activities and high population densities. Most studies showed the decline of macrophytes and predation on several species (amphibians, molluscs, and macroinvertebrates), highlighting how this biodiversity loss leads to changes in ecosystem service. It can cause also important economic damages, inducing the collapse of banks thanks to its digging activity and impacting the rice production by consuming the young plants. For its ecological impacts, the species has been included in the list of Invasive Alien Species of Union concern linked to the EU Regulation 1143/2014, and its management is mandatory for the European Member States, Italy included. An integrated approach is recommended to tackle this species and several measures have been applied to control and reduce its populations. Some successful management projects will be illustrated during the presentation.
Crustacean molt physiology: phosphate transporter in crayfish biomineralization
Shai Avraham Shaked (1, 2) Simy Weil (1), Rivka Manor (1), Eliahu David Aflalo (1,3,) Jerry Eichler (1) & Amir Sagi (1, 2)
1) Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel. 2)The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel. 3)Department of Life Sciences, Achva Academic College, Shikmim, Israel
Dr. Shai Avraham Shaked (Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel. The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel)
Abstract: Crustacean molt physiology is widely studied with processes ranging from developing a larger exoskeleton for growth to morphological changes in a new exoskeleton. The Redclaw crayfish Cherax quadricarinatus is used as a model animal to study the molt cycle, its physiology and key proteins involved in biomineralization of the exoskeleton. Like many other invertebrates, crustaceans mineralize their exoskeletons primarily by calcium carbonate in different polymorphs. C. quadricarinatus utilizes the stabile amorphous form of CaCO3 (ACC) in parts of its exoskeleton and gastroliths (transient calcium storage organs). The stabilization of amorphous calcium carbonate was thought to be controlled by phosphate ions (Pi), thus the role of phosphate transporters in crayfish molt cycle and mineralization was studied. A molt-related transcriptomic library and a novel binary patterning approach were exploited to reveal a SLC20A2 transport protein encoding gene in the crayfish C. quadricarinatus. Functional genomics experiments using RNAi demonstrated that Cq-SLC20A2 transport of phosphate to the mineralization site of amorphous calcium carbonate (ACC) at the exoskeleton. Following silencing, increased crystallinity of ACC was demonstrated at the gastroliths together with noted reduction in phosphate content (Fig. 1). This first discovery of the involvement of Cq-SLC20 in crustacean exoskeletal mineralization through phosphate active transport sheds light on long hypothesized putative role for Pi in CaCO3 biomineralization.
Figure 1. Pi content in gastroliths during the molt cycle following RNAi-induced loss-of-function of CqSLC20A2. Calcium and phosphate distribution in a representative control animal injected with dsGFP (left) and calcium and phosphate distribution in a representative animal of the silenced group injected with dsCqSLC20A2 (right). Purple – calcium. Red – Phosphate.
Monosex prawns and crayfish as environmental biocontrol agents against pest snails
Sharon Moscovitz (1), Shai Avraham Shaked (1, 2), Hanin Wattad (1), Hanoch Glassner (3), Eliahu D. Aflalo (1, 4), Ofer Ovadia (1) & Amir Sagi (1,2)
1) Department of Life Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel. 2) National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva, Israel. 3) Eden Research Station, Beit She'an, Israel. 4 Department of Life Sciences, Achva Academic College, Shikmim, Israel
Sharon Moscovitz (Department of Life Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel)
We examined the predation abilities of prawns on four species of aquacultural pest SBD transmitting snails which are found together in the field: Melanoides tuberculata, Tarebia granifera, Thiara scabra and Pseudosuccinea columella. The prawn was previously proven a successful size-selective predator of M. tuberculata and T. scabra in the lab and field. In our following food-choice experiment, M. rosenbergii was successful in predating all four species, showing a preference for the soft-shelled snail first (P. columella) and the hard-shelled snail the least (T. scabra).
We subsequently examined the predation abilities of C. quadricarinatus against the hard-shelled species, and size-grade preferences by presenting small and medium snails. We found it a faster predator than the prawn, and very efficient with nearly 100% predation of the snails in both sizes.
We will discuss both predators as biocontrol agents in snail-struck areas and in agricultural polyculture, with the ability to choose the better suiting crustacean for the specific snail-control purpose. Furthermore, considering the requirements of biocontrol agents to be noninvasive themselves, we encourage strictly monosex crustacean populations as safely monitored biocontrol, and an additive crop on their own, as a win-win-win sustainable snail and SBD solution.
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