Mantis Shrimp Research Articles

Transcriptome analysis and identification of differentially expressed genes between early and mature ovarian stages in the female mantis shrimp (Harpiosquilla raphidea) using RNA-Seq

Harpiosquilla raphidea, the largest of the mantis shrimps, is a commercially important crustacean species widely distributed in many countries of the Pacific Ocean. However, no data are currently available regarding the molecular mechanisms that regulate reproduction in this species. To address this knowledge gap, we performed transcriptome sequencing (RNA-Seq) of previtellogenic and vitellogenic ovaries of female H. raphidea, and compared the expression patterns of transcripts from the two resulting libraries to identify genes involved in ovarian development. A total of 418,635,748 clean reads were retrieved after removing adapter sequences and filtering out low-quality data. The reads were assembled into 242,861 unigenes with an average length of 585.27 base pairs (bp) and an N50 of 829 bp. A search of all unigenes against the NR (non-redundant protein), SwissProt, KEGG, GO, and COG databases yielded 53,111; 25,460; 27,255; 26,793; and 3838 unigene matches, respectively). Of the 53,111 unigenes identified in the NR database, 30,441 could be functionally annotated, 59.49% of which were significantly matched with the transcripts of L. vannamei. A total of 13,867 full-length transcripts and 11,441 partial transcripts were retrieved. In addition, using all-unigenes as a reference, a total of 12,765 simple sequence repeats (SSRs) were identified. DESeq2 analysis identified a total of 962 differentially expressed genes (DEGs) between previtellogenic and vitellogenic ovaries, 456 of which were upregulated and 506 downregulated. Five unigenes were validated by quantitative real-time PCR (qPCR). The results of both the RNA-Seq and qPCR analysis revealed that the H. raphidea vitellogenin gene (HrVtg) was upregulated in vitellogenic ovaries. The open reading frame of HrVtg was found to be 7455 bp long, corresponding to a polypeptide of 2485 amino acids. The important functional genes and pathways identified here provide a valuable dataset for understanding the molecular mechanisms controlling ovarian development in H. raphidea.

Biomimetic Bouligand chiral fibers array enables strong and superelastic ceramic aerogels

Ceramic aerogels are often used when thermal insulation materials are desired; however, they are still plagued by poor mechanical stability under thermal shock. Here, inspired by the dactyl clubs of mantis shrimp found in nature, which form by directed assembly into hierarchical, chiral and Bouligand (twisted plywood) structure exhibiting superior mechanical properties, we present a compositional and structural engineering strategy to develop strong, superelastic and fatigue resistance ceramic aerogels with chiral fibers array resembling Bouligand architecture. Benefiting from the stress dissipation, crack torsion and mechanical reinforcement of micro-/nano-scale Bouligand array, the tensile strength of these aerogels (170.38 MPa) is between one and two orders of magnitude greater than that of state-of-the-art nanofibrous aerogels. In addition, the developed aerogels feature low density and thermal conductivity, good compressive properties with rapid recovery from 80 % strain, and thermal stability up to 1200 °C, making them ideal for thermal insulation applications.

The Super Tough Saddle of Mantis Shrimp Derived from Strain Transformation Between Helical Fibers and Interlaminar Fibrils

AbstractMantis shrimps deliver one of the fastest strikes with their powerful dactyl clubs. The kinematic energy derived by a saddle storing and releasing mechanical energy with large deformation. As an exoskeleton, the toughness of saddles can achieve a remarkable value ≈15.28 ± 2.32 MJ m−3, which exceeds most bulk natural materials. The excellent toughness of saddles is mainly attributed to the synergy of the helical mineralized fiber architectures and interlaminar fibrils. The interlaminar fibrils connect adjacent mineralized fiber layers closely, enhancing the toughness through viscoelastic deformation during sliding and separating of adjacent layers. They further cooperate with rigid interlacing fiber structure induced by helical structure to transform little normal strain to large shear strain utilizing incompressibility of soft fibrils further to enhance strain energy for toughening. Inspired by unique laminated saddles, the laminate composites are designed with basalt fabrics achieving remarkable fracture toughness to solve the problem of delamination in traditional laminate composites with poor interlaminar toughness. The Mode I and Mode II interlaminar fracture toughness of bio‐inspired laminate composites respectively increase by 44% and 118% reaching 906.8 and 1394.6 J m−2, which provides an innovative bionic strategy for designing new generation structural engineering materials with excellent mechanical properties.

Development of a PCR Method to Detect a Mysid Species Causing False Positives in Tests for Crustacean Allergens

Mysids are small crustaceans that are closely related to shrimp/prawns and crabs but not subject to food allergen labeling requirements for raw materials. In the past, a processed food that contained Japanese smelt (wakasagi) was suspected of producing a false-positive result in shrimp/prawn and crab allergen test because of the presence of consumed mysids. However, there was no reported methods to confirm mysid presence. Therefore, we developed a PCR method to detect mysids. The developed PCR method had high specificity for a mysid species, with no amplification observed from samples of shrimp, crab, krill, mantis shrimp, or the meat of Japanese smelt. In addition, DNA extracted from the internal organs of Japanese smelt was amplified by this PCR method, and sequencing revealed mysid DNA. This confirmed that mysids remained in the internal organs of Japanese smelt following consumption. This PCR method for mysid detection even amplified Japanese smelt-containing processed food samples that were suspected to have produced a false-positive result in shrimp/prawn and crab ELISA. Thus, this PCR method would enable to detect such false positives are caused by mysid contamination.

A Design Method for Instantaneous Force Generation Based on a Mantis Shrimp With Exoskeleton Spring

A Design Method for Instantaneous Force Generation Based on a Mantis Shrimp With Exoskeleton Spring

How Oratosquilla oratoria compound eye response to the polarization of light: In the perspective of vision genes and related proteins

The special rhabdom structure of the mid-band ommatidium in compound eye contributes to the mantis shrimp being the only animal species known to science that can recognize circularly polarized light (CPL). Although the number of mid-band ommatidium of Oratosquilla oratoria is reduced, the mid-band ommatidium still has orthogonal geometric interleaved rhabdom and short oval distal rhabdom, which may mean that the O. oratoria has weakened circular polarized light vision (CPLV). Here we explored the molecular mechanisms of how O. oratoria response to the polarization of light. Based on the specific expression patterns of vision-related functional genes and proteins, we suggest that the order of light response by O. oratoria compound eye was first natural light, then left-circularly polarized light (LCPL), linearly polarized light, right-circularly polarized light (RCPL) and dark. Meanwhile, we found that the expression levels of vision-related functional genes and proteins in O. oratoria compound eye under RCPL were not significantly different from those in DL, which may imply that O. oratoria cannot respond to RCPL. Furthermore, the response of LCPL is likely facilitated by the differential expression of opsin and microvilli - related functional genes and proteins (arrestin and sodium-coupled neutral amino acid transporter). In conclusion, this study systematically illustrated for the first time how O. oratoria compound eye response to the polarization of light at the genetic level, and it can improve the visual ecological theory behind polarized light vision evolution.

Full-length transcriptome reveals the circularly polarized light response-related molecular genetic characteristics of Oratosquilla oratoria

The mantis shrimp is the only animal that can recognize circularly polarized light (CPL), but its molecular genetic characteristics are unclear. Multi-tissue level full-length (FL) transcriptome sequencing of Oratosquilla oratoria, a representative widely distributed mantis shrimp, was performed in the present study. We used comparative transcriptomics to explore the critical genes of O. oratoria selected by CPL and the GNβ gene associated with CPL signal transduction was hypothesized to be positively selected. Furthermore, the FL transcriptomes of O. oratoria compound eyes under five light conditions were sequenced and used to detect alternative splicing (AS). The ASs associated with CPL recognition mainly occurred in the LWS, ARR and TRPC regions. The number of FL transcripts with AS events and annotation information also provided evidence that O. oratoria could recognize LCPL. Additionally, 51 sequences belonging to the LWS, UV and Peropsin gene families were identified based on conserved 7tm domains. The LWS, UV and Peropsin opsins have similar 3D structures with seven domains across the cell membrane and conserved KSLRTPSN, DRY, and QAKK motifs. In conclusion, these results are undoubtedly valuable for perfecting the vision theory of O. oratoria and other mantis shrimp.

Impact of Prior Pulsed Electric Field and Chitooligosaccharide Treatment on Trypsin Activity and Quality Changes in Whole and Beheaded Harpiosquillid Mantis Shrimp during Storage in Iced Water.

Harpiosquillid mantis shrimp (Harpiosquilla raphidea) (HMS) without and with beheading pretreated with pulsed electric field (PEF) (15 kV/cm, 800 pulses, 5 min) were soaked in chitooligosaccharide (COS) solution at varying concentrations (0, 1 and 2%, w/v) for 20 min and stored for 3 days in iced water. Changes in the trypsin activity, color, texture, protein pattern, TCA soluble peptide content, histological images, protein secondary structure and microbial load were monitored during the storage. The beheaded HMS pretreated with PEF and soaked in 2% COS solution showed the maximum efficacy in inhibiting trypsin activity and proteolysis, thus retaining muscle proteins, especially myosin heavy chain, actin and troponin T as well as shear force up to day 3. Pronounced muscle destruction in the whole HMS was displayed by a decreased mean grey index and fiber gapping. Such changes were lowered by the beheading and PEF/2% COS treatment (2% COS-BH). Nevertheless, no marked change in the secondary structure including α-helix, β-sheets, β-turns and random coil were observed among any of the samples. The microbiological analysis revealed that the total viable count (TVC) was below 6 log CFU/g till day 2 in all samples. Nonetheless, the 2% COS-BH sample had the lowest psychrophilic bacterial count and Enterobacteriaceae count at day 3, compared to the others. Thus, the combination of the prior PEF and 2% COS treatment of beheaded HMS could effectively inhibit proteases, retard the microbial growth and maintain the quality of HMS stored in iced water.

Performance of sorting grids on catching elasmobranchs in a multispecies Mediterranean bottom trawl fishery

Elasmobranchs are among the most threatened long-lived marine species in the Mediterranean Sea. Incidental catch and intense fishing effort are considered the major threats to their conservation. To date, no Mediterranean countries has adopted specific technical measures within current conservation plans to mitigate potential impacts on vulnerable elasmobranchs. This study aimed to evaluate the effectiveness of new elasmobranch bycatch reducing devices (BRD) in a Mediterranean multispecies bottom trawl fishery (northern central Adriatic Sea, one of the most exploited basins in the Mediterranean). Specifically, two types of grids were tested: a novel shark excluder device (SED) and a flexible grid (Flexgrid). Effectiveness was evaluated in terms of bycatch and commercial catch reduction, relying on the different sizes of elasmobranchs and the main commercial species. Results showed that preliminary tests with SED were effective in excluding elasmobranch species. Catches made with this grid showed no significant difference for targeted crustacean (mantis shrimp, Squilla mantis), however, commercial losses were shown for some large bony fish. Flexgrid did not affect the catches of the main target species, such as the red mullet (Mullus barbatus), European hake (Merluccius merluccius) and mantis shrimp, but also retained small-spotted catshark (Scyliorhinus canicula). The effectiveness of the grids apparently was affected by the small size of the elasmobranchs captured. The study showed that SED and Flexgrid are valuable solutions for elasmobranchs if combined with other conservation measures (e.g. seasonal fishing closure in critical areas and good practices). Finally, strong cooperation between fishers, scientists, and managers is critical to identify the best management options in a regulatory framework where only a few elasmobranch species are formally protected. Interestingly, the study also yielded the identification of two potential aggregation-nursery areas for the small-spotted catshark (Scyliorhinus canicula) and the common smooth-hound (Mustelus mustelus).

First DNA barcoding-based record of Lysiosquilla maculata (Crustacea: Stomatopoda) from Chennai coast, Tamil Nadu, India

The taxonomic identification of mantis shrimp Lysiosquilla maculata was performed through DNA barcoding analysis of specimens collected from the Kasimedu fishing port, Chennai coast, Tamil Nadu, India. The mitochondrial cytochrome oxidase subunit I (mtCOI) gene with a region of 650 bp was sequenced for phylogenetic analysis. In the present record, mitochondrial gene sequences were used to identify the mantis shrimp. This is the first confirmed DNA barcoding record from Indian waters, whose mtCOI sequence was deposited in GenBank. The Neighbor-joining method was used for phylogenetic analysis. The calculated pairwise genetic distance with five closely related species ranged from 0.01 to 0.094%. The morphological and molecular analysis confirm that the specimens collected correspond to L. maculata.

Invited Session III: Diversity in chromatic processing across the animal kingdom: Color vision in stomatopod crustaceans.

Stomatopod crustaceans, commonly known as mantis shrimp, have perhaps the most unusual color-vision systems of any animals. The uniqueness is possible because stomatopods have compound eyes. Here, each unit, or ommatidium, acts as an independent visual detector, with its own corneal lens, internal optics, and set of photoreceptors. Ommatidia tuned to different wavelengths can be individually placed in the eye to build unusual color systems. In mantis shrimps, the receptors responsible for color vision are limited to six parallel rows of ommatidia that together form an equatorial belt, called the midband. Various receptors in these ommatidia are tuned to eight narrow-band spectral channels in the visible spectrum plus up to four additional ultraviolet channels. Thus, there is a total of twelve different color receptors for color vision. How these color channels are analyzed in the complex set of optic lobes existing behind the retina is only partly understood. It appears that stomatopods use both opponent and labelled-line color channels. Oddly, these animals appear to have limited ability to discriminate between spectral lights, but they have outstanding color constancy. Color vision, and color processing, in stomatopods is probably unlike that of any other animal group.

Design and Control of a Novel Bionic Mantis Shrimp Robot

Design and Control of a Novel Bionic Mantis Shrimp Robot

Izod impact resistance of 3D printed discontinuous fibrous composites with Bouligand structure

The Bouligand structure found in the dactyl club of mantis shrimps is known for its impact resistance. However, Bouligand-inspired reinforced composites with 3D shapes and impact resistance characteristics have not yet been demonstrated. Herein, direct ink writing was used to 3D print composites reinforced with glass microfibers assembled into Bouligand structures with controllable pitch angles. The energy absorption levels of the Bouligand composites under impact were found to surpass those of composites with unidirectional microfiber alignment. Additionally, the Bouligand composites with a pitch angle of 40° exhibited a maximum energy absorption of 2.4 kJ/m2, which was 140% higher than that of the unidirectional composites. Furthermore, the characterization of the topography of the fractured surface, supplemented with numerical simulations, revealed a combination of crack twisting and crack bridging mechanisms. Flexural tests conducted on the composites with a pitch angle of 40° revealed that these composites had the strongest properties, including a flexural strength of 36.9 MPa, a stiffness of 2.26 GPa, and energy absorption of 8 kJ/m2. These findings are promising for the microstructural design of engineered composites using direct ink writing for applications in aerospace, transportation, and defense.

A Rarely Reported Crustacean Species, Rissoides pallidus (Giesbrecht, 1910) (Stomatopoda, Squillidae), Caught in the Strait of Sicily Waters (Central Mediterranean Sea)

The mantis shrimp Rissoides pallidus (Giesbrecht, 1910) is a rarely reported crustacean species in the central Mediterranean Sea. In December 2020, during a trawl survey off Mazara del Vallo harbor (Strait of Sicily), two specimens of R. pallidus were captured on coastal detritus and coastal terrigenous mud bottoms at about 132 and 152 m depths. Additional information specific to biometrics, bottom types, depth preference, habitats, and geographic distribution of this crustacean species are provided.

Molecular Identification and Phylogenetic Analysis of Bioluminescent Bacteria Isolated from Selected Marine Crustacean in Manila Bay, Philippines

Bioluminescent bacteria (BLB) are the most widely distributed light-emitting microorganisms, most of which are found as symbionts of free-living marine organisms, including the crustacean species. In this study, 4 out of 7 marine crustaceans in the northeastern section of Manila Bay were found to contain bioluminescent bacteria. Marine crustacean species namely Thenus orientalis (Oriental Slipper Lobster), Oratosquilla oratoria (Mantis Shrimp), Penaeus monodon (Giant Tiger Prawn), Litopenaeus vannamei (Whiteleg shrimp), Scylla serrata (Mud Crab), Portunus pelagicus (Blue Swimming Crab), and Charybdis feriata (Crucifix crab), were swabbed after collection. Bioluminescent bacteria were isolated from the inner surface of the carapace, eyes, abdomen, and abdominal segments of the crustacean samples. All glowing colonies were isolated and upscaled. Only bioluminescent bacteria from T. orientalis, O. oratoria, and P. monodon completed the isolation process and were identified using 16S rRNA gene sequencing for phylogenetic analysis. Furthermore, results from molecular identification through Nucleotide BLAST identified that it was Vibrio alginolyticus and Mucus bacterium. At the same time, the presence of Vibrio rumoiensis was also identified which was proved to be understudied and needs exploration. This study was aimed to identify the present bioluminescent bacteria in selected marine crustaceans in Manila Bay, Philippines through microbiological isolation, molecular identification, and phylogenetic reconstruction.

Numerical study on energy absorption performance of novel bionic helmet liner

In this paper, by introducing the pyramid-shaped spine configuration of durian shells and bidirectional corrugated configuration of jaw feet of mantis shrimps into the helmet liner, a bidirectional staggered rectangular frustum liner was designed. Finite element simulation of impact was carried out on liners with various pyramid-shaped cell structures, and the kinetic behavior of the liners of different structures during impact compression was studied. The results showed that the decrease in the inclination angle of the outer walls of pyramid-shaped cells and the bidirectional-cell design can both improve the specific energy absorption of the helmet, and that the bidirectional staggered rectangular frustum helmet has the highest specific energy absorption, 2.7 times that of the gradient lattice or 1.3 times that of the honeycomb helmet. This is because the bidirectional staggered rectangular frustum cell design enhances the connection between adjacent cell walls, resulting in a larger deformation area during the impact process and participation of more material in energy storage, thus significantly improving the overall energy absorption performance.

An ingenious composite microstructure of mantis shrimp appendage for improving impact resistance

Mantis shrimp appendage, as an important weapon for hunting, have remarkable impact resistance due to their unique microstructure. In this study, the appendages were subjected to falling ball impact tests and their fracture surfaces were observed by scanning electron microscopy. It was observed that the outer layer was prone to brittle fracture, while the inner layer was more flexible and turned the brittle fracture into a ductile fracture. Our study supported the idea that the unique microstructures in the appendages act as barriers against crack growth and therefore play a leading role in the toughening of the entire appendage structure. Based on the bionic inspiration of the appendage microstructure, a bionic composite structure was designed, which consists of a rigid outer layer and a flexible inner layer. The fibers in the flexible layer show a longitudinal and sinusoidal arrangement to provide shielding to the crack tip when the fracture occurs. The toughening mechanism of the microstructure was further corroborated through finite element simulations, which demonstrated that the longitudinal arrangement of fibers played a pivotal role in spreading stress concentration and thereby delaying the fracture process. The sinusoidal arrangement of fibers was also found to be instrumental in not only bridging the rigid and flexible layers, but also in directing the deviation of the crack path. This work was enlightening for the structural design of impact-resistant composites.

Comparative transcriptome analysis of eyes reveals the adaptive mechanism of mantis shrimp (oratosquilla oratoria) induced by a dark environment.

The light-dark cycle significantly impacts the growth and development of animals. Mantis shrimps (Oratosquilla oratoria) receive light through their complex photoreceptors. To reveal the adaptive expression mechanism of the mantis shrimp induced in a dark environment, we performed comparative transcriptome analysis with O. oratoria cultured in a light environment (Oo-L) as the control group and O. oratoria cultured in a dark environment (Oo-D) as the experimental group. In the screening of differentially expressed genes (DEGs) between the Oo-L and Oo-D groups, a total of 88 DEGs with |log2FC| > 1 and FDR < 0.05 were identified, of which 78 were upregulated and 10 were downregulated. Then, FBP1 and Pepck were downregulated in the gluconeogenesis pathway, and MKNK2 was upregulated in the MAPK classical pathway, which promoted cell proliferation and differentiation, indicating that the activity of mantis shrimp was slowed and the metabolic rate decreases in the dark environment. As a result, the energy was saved for its growth and development. At the same time, we performed gene set enrichment analysis (GSEA) on all DEGs. In the KEGG pathway analysis, each metabolic pathway in the dark environment showed a slowing trend. GO was enriched in biological processes such as eye development, sensory perception and sensory organ development. The study showed that mantis shrimp slowed down metabolism in the dark, while the role of sensory organs prominent. It provides important information for further understanding the energy metabolism and has great significance to study the physiology of mantis shrimp in dark environment.

Effects of proteases on textural softening and changes in physical property of harpiosquillid mantis shrimp (Harpiosquilla raphidea) during the iced storage

SummaryRapid softening of texture is a major problem associated with quality loss and consumer rejection of harpiosquillid mantis shrimp (Harpiosquilla raphidea) (HMS). Effects of endogenous proteases in muscles and digestive tract on protein degradation and softening were investigated. Scanning electron microscopic and histological images indicated drastic destruction of muscle during iced storage. Based on autolysis, maximal activity was found at pH 8.5 and 55 °C, and serine proteases including trypsin were dominant. Cathepsin B and L + B in muscle were altered throughout storage, while trypsin remained constant in HMS meat for 1–3 days. Firmness and toughness decreased and coincided with augmented degradation of myofibrillar proteins and collagen. Trypsin from the digestive tract was contaminated into the abdomen during iced storage, therefore inducing drastic hydrolysis of muscle proteins. This phenomenon caused the undesirable pasty/mushy texture associated with the loss in firmness and toughness of meat within 3 days of storage.

Biomineralization of mantis shrimp dactyl club following molting: Apatite formation and brominated organic components

The stomatopod Odontodactylus scyllarus uses weaponized club-like appendages to attack its prey. These clubs are made of apatite, chitin, amorphous calcium carbonate, and amorphous calcium phosphate organized in a highly hierarchical structure with multiple regions and layers. We follow the development of the biomineralized club as a function of time using clubs harvested at specific times since molting. The clubs are investigated using a broad suite of techniques to unravel the biomineralization history of the clubs. Nano focus synchrotron x-ray diffraction and x-ray fluorescence experiments reveal that the club structure is more organized with more sub-regions than previously thought. The recently discovered impact surface has crystallites in a different size and orientation than those in the impact region. The crystal unit cell parameters vary to a large degree across individual samples, which indicates a spatial variation in the degree of chemical substitution. Energy dispersive spectroscopy and Raman spectroscopy show that this variation cannot be explained by carbonation and fluoridation of the lattice alone. X-ray fluorescence and mass spectroscopy show that the impact surface is coated with a thin membrane rich in bromine that forms at very initial stages of club formation. Proteomic studies show that a fraction of the club mineralization protein-1 has brominated tyrosine suggesting that bromination of club proteins at the club surface is an integral component of the club design. Taken together, the data unravel the spatio-temporal changes in biomineral structure during club formation. Statement of significanceMantis shrimp hunt using club-like appendages that contain apatite, chitin, amorphous calcium carbonate, and amorphous calcium phosphate ordered in a highly hierarchical structure. To understand the formation process of the club we analyze clubs harvested at specific times since molting thereby constructing a club formation map. By combining several methods ranging from position resolved synchrotron X-ray diffraction to proteomics, we reveal that clubs form from an organic membrane with brominated protein and that crystalline apatite phases are present from the very onset of club formation and grow in relative importance over time. This reveals a complex biomineralization process leading to these fascinating biomineralized tools.