Published Papers - Ikeda Yuzuru

Evolutionary history influences the microbiomes of a female symbiotic reproductive organ in cephalopods

Nidhi Vijayan, Sarah J. McAnulty, Gustavo Sanchez, Jeffrey Jolly, Yuzuru Ikeda, Michele K. Nishiguchi, Elodie Réveillac, Camino Gestal, Blake L. Spady, Diana H. Li, Benjamin P. Burford, Allison H. Kerwin, Spencer V. Nyholm

Applied and Environmental Microbiology ( American Society for Microbiology )  90 ( 3 )   2024.02 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

ABSTRACT Many female squids and cuttlefishes have a symbiotic reproductive organ called the accessory nidamental gland (ANG) that hosts a bacterial consortium involved with egg defense against pathogens and fouling organisms. While the ANG is found in multiple cephalopod families, little is known about the global microbial diversity of these ANG bacterial symbionts. We used 16S rRNA gene community analysis to characterize the ANG microbiome from different cephalopod species and assess the relationship between host and symbiont phylogenies. The ANG microbiome of 11 species of cephalopods from four families (superorder: Decapodiformes) that span seven geographic locations was characterized. Bacteria of class Alphaproteobacteria, Gammaproteobacteria , and Flavobacteriia were found in all species, yet analysis of amplicon sequence variants by multiple distance metrics revealed a significant difference between ANG microbiomes of cephalopod families (weighted/unweighted UniFrac, Bray–Curtis, P = 0.001). Despite being collected from widely disparate geographic locations, members of the family Sepiolidae (bobtail squid) shared many bacterial taxa including (~50%) Opitutae (Verrucomicrobia) and Ruegeria (Alphaproteobacteria) species. Furthermore, we tested for phylosymbiosis and found a positive correlation between host phylogenetic distance and bacterial community dissimilarity (Mantel test r = 0.7). These data suggest that closely related sepiolids select for distinct symbionts from similar bacterial taxa. Overall, the ANGs of different cephalopod species harbor distinct microbiomes and thus offer a diverse symbiont community to explore antimicrobial activity and other functional roles in host fitness. IMPORTANCE Many aquatic organisms recruit microbial symbionts from the environment that provide a variety of functions, including defense from pathogens. Some female cephalopods (squids, bobtail squids, and cuttlefish) have a reproductive organ called the accessory nidamental gland (ANG) that contains a bacterial consortium that protects eggs from pathogens. Despite the wide distribution of these cephalopods, whether they share similar microbiomes is unknown. Here, we studied the microbial diversity of the ANG in 11 species of cephalopods distributed over a broad geographic range and representing 15–120 million years of host divergence. The ANG microbiomes shared some bacterial taxa, but each cephalopod species had unique symbiotic members. Additionally, analysis of host–symbiont phylogenies suggests that the evolutionary histories of the partners have been important in shaping the ANG microbiome. This study advances our knowledge of cephalopod–bacteria relationships and provides a foundation to explore defensive symbionts in other systems.

• Access this article

  DOI

Relationship between seasonal seagrass growth and egg case dynamics of the oval squid (Sepioteuthis lessoniana Férussac in Lesson, 1832) in the coastal waters of the Ryukyu Archipelago

Sho Kimoto, Ritsuki Kawabata, Yuzuru Ikeda

Regional Studies in Marine Science ( Elsevier BV )  67   103190 - 103190   2023.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

Allometry for Eyes and Optic Lobes in Oval Squid (Sepioteuthis lessoniana) with Special Reference to Their Ontogenetic Asymmetry

Yuma Sakurai, Yuzuru Ikeda

Symmetry ( MDPI AG )  14 ( 4 ) 644 - 644   2022.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Eyes develop in relation to body size and brain area for visual processing in some vertebrates. Meanwhile, it is well known that many animals exhibit left–right asymmetry in both morphology and behavior, namely, lateralization. However, it remains unclear whether the eyes and visual processing brain areas synchronously develop for their asymmetry. Oval squid (Sepioteuthis lessoniana) exhibits lateralization of optic lobe volume and left or right eye usage toward specific targets during their ontogeny. We address the question of how left–right asymmetry of the eyes and optic lobes exhibit an allometric pattern. To examine this question, we estimated the left and right volumes of eyes and optic lobes using microcomputed tomography. We found that, for the optic lobe volume, the right enlargement that appeared at ages 45 and 80 days then shifted to the left at age 120 days. In contrast, the volume of eyes did not show any left–right asymmetries from hatching to age 120 days. We also found that the volume of the eyes and optic lobes showed a slower increase than that of the whole-body size. Within these two visually related organs, the eyes grew faster than the optic lobes until age 120 days. These results are discussed in the context of the survival strategy of oval squid that form schools, two months post-hatching.

• Access this article

  DOI

Visual and brain lateralization during the posthatching phase in squid under solitary and group conditions

Yuma Sakurai, Yuzuru Ikeda

Animal Behaviour ( Elsevier BV )  183   13 - 28   2022.01 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

Evaluation of Visual and Tactile Perception by Plain-Body Octopus (<i>Callistoctopus aspilosomatis</i>) of Prey-Like Objects.

Kawashima S, Ikeda Y

Zoological science ( Zoological Science )  38 ( 6 ) 495 - 505   2021.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI
• Search related information
  PubMed

Morphology of the suckers for hunting behavior in broadclub cuttlefish (Sepia latimanus)

Omura A.

Ecological Research ( Ecological Research )  37 ( 1 ) 156 - 162   2021.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

Plain-body Octopus's (<i>Callistoctopus aspilosomatis</i>) Learning About Objects via Both Visual and Tactile Sensory Inputs: a Pilot Study

Kawashima, S; Yasumuro, H; Ikeda, Y

ZOOLOGICAL SCIENCE ( Zoological Science )  38 ( 5 ) 383 - 396   2021.10 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Although various recognizing abilities have been revealed for octopuses, they predominantly deal with only a few species. Therefore, cognition diversity among other octopus species that have been overlooked needs to be investigated. We investigated whether plain-body octopus can learn a symbolic stimulus, for the reason that this octopus is abundant around Okinawa Island with a complex coral community landscape. Attention was paid to whether an octopus can learn a stimulus based solely on visual information without previous experience of learning it tactilely as well as visually. Furthermore, we examined whether different sensory inputs affect learning in octopuses. First, we tested whether octopuses can be conditioned to three different stimuli (object, picture, and video of a white cross). Octopuses that were presented an object or a picture could learn to touch them. However, octopuses that were presented a video could not learn to touch the stimulus. Second, we showed a video to octopuses that had already learned about an object or a picture to investigate whether the octopuses, having experienced a target using visual and tactile senses, can recognize a video of the target based solely on visual information. Octopuses could learn to touch the video. When a conditioned stimulus and a novel stimulus were simultaneously presented on a computer screen, an octopus that had learned an object more often selected the conditioned stimulus when compared with an octopus that had experienced only a picture. These findings suggest that octopuses use multisensory information to recognize a specific object.

• Access this article

  DOI
• Search related information
  PubMed

Plain-body octopus's (Callistoctopus aspilosomatis) learning about objects via both visual and tactile sensory inputs: A pilot study.

Sumire Kawashima, Haruhiko Yasumuro, Yuzuru Ikeda

Zoological Science   38 ( 5 ) 383 - 396   2021.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

Sociality and communication of cephalopods

Yuzuru Ikeda

Aquabiology   43 ( 2 ) 154 - 158   2021.04

Type of publication: Research paper (scientific journal)

Ontogenetic trajectories of septal spacing in modern cuttlefishes are phylogenetically dependent

Noba K.

Lethaia ( Lethaia )  53 ( 4 ) 563 - 573   2020.10 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

Tropical Octopus <i>Abdopus aculeatus</i> Can Learn to Recognize Real and Virtual Symbolic Objects.

Kawashima S, Takei K, Yoshikawa S, Yasumuro H, Ikeda Y

The Biological bulletin ( Biological Bulletin )  238 ( 1 ) 12 - 24   2020.02 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI
• Search related information
  PubMed

The diverse morphology of decapodiform cephalopods: A summer lecture

Ayano Omura, Yuzuru Ikeda

Contemporary Mathematics and Science Education   1 ( 1 ) ep20005   2020 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Survival of squid, Aka-ika, Sepioteuthis sp. 1, hatched from egg cases exposed to stressful conditions during the early-middle embryonic stage of development

Akira Amida, Hisaya Washitake, Takuma Kimura, Tetsuya Umino, Yuzuru Ikeda

Aquaculture Science   67 ( 3 ) 241 - 248   2020 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Development of a contrast-enhanced micro computed tomography protocol for the oval squid (Sepioteuthis lessoniana) brain.

Sakurai Y, Ikeda Y

Microscopy research and technique ( Microscopy Research and Technique )  82 ( 11 ) 1941 - 1952   2019.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI
• Search related information
  PubMed

Preliminary report of specific behaviours of juvenile greater blue-ringed octopus Hapalochlaena lunulata (Quoy and Gaimard, 1832)

Kawashima Sumire, Amida Akira, Ikeda Yuzuru

MOLLUSCAN RESEARCH ( Molluscan Research )  39 ( 4 ) 291 - 295   2019.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI

タコにおける視覚・触覚にもとづく行動:タコは世界をクロスモーダルに知覚しているのか?

川島 菫, 池田 譲

動物心理学研究 ( 日本動物心理学会 )  69 ( 2 ) 91 - 99   2019 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

<p>Octopuses, a member of molluscan class, possess well-developed nervous system such as lens eyes that is anatomically similar to our own, and the relative proportion of brain to body is equivalent to vertebrates. Octopuses are also characterized with their muscular highly sensitive sensory receptors, namely, suckers on their arms. Due to these biological uniqueness, octopuses have been a target for psychological studies and were reported their advanced abilities for learning and memory, which are achieved via visual and tactile perceptions. All of these findings have come from experiments that tested single sensory perception (i.e., visual or tactile). On the other hand, it is known in vertebrates that they can integrate multiple sensory information, by which they can vividly image their environments. In this review, we will briefly introduce our knowledge for biology of octopuses with special reference to their cognition, and we will shed light on an idea for cross-modal perception in octopuses, which is based on our on-going projects for visual and tactile learning, and manipulation of arms in tropical octopuses inhabiting the coastal waters of the Ryukyu Archipelago.</p>

• Access this article

  DOI

胚発生期にストレス条件に置かれたアオリイカ類アカイカ型の生残

網田 全, 和志武 尚弥, 木村 琢磨, 海野 徹也, 池田 譲

水産増殖 ( 日本水産増殖学会 )  67 ( 3 ) 241 - 248   2019 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

<p>琉球列島近海の水深50-100 m に海上保安庁が設置した流速計に，アオリイカ類アカイカ型の卵塊が異なる3 つの年に産み付けられた。これら卵塊のうちの1 つは，採集直後の25時間程度，海水を含まないビニールパックに容れて冷蔵庫（8℃）に保存された。その後，この卵塊を閉鎖型循環水槽にて飼育したところ，正常発生を経て高率で孵化が見られ，孵化個体は4 か月間にわたり生残した。 一方，琉球列島近海の水深15-20 m に設置した人工産卵礁に産み付けられた孵化直近のアオリイカ類アカイカ型卵塊を採集し，前記の卵塊と同様の条件で飼育したところ，高率で孵化し，一部は性成熟に達した。これら2 つの卵塊由来の孵化個体の生残，成長を比較したところ，両者に違いは見られなかった。本研究はアオリイカ類アカイカ型の卵および孵化個体の初めての長期飼育記録であり，本種の卵嚢がストレス時に胚を防衛する機能を有することを示すものである。</p>

• Access this article

  DOI

Activity rhythms of the shallow-water octopuses Octopus laqueus and Abdopus aculeatus with special reference to its relation to light and tidal cycles

Yuzuru Ikeda, Ryoko Yanagisawa

Biological Rhythm Research ( Taylor and Francis Ltd. )  49 ( 4 ) 566 - 580   2018.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

Patterns of activity and inactivity were experimentally measured for two shallow-water octopuses, Octopus laqueus (n = 8) and Abdopus aculeatus (n = 4), inhabiting the Ryukyu Archipelago. Octopuses that were collected from the coastal waters of Okinawa Island were held in experimental tanks under controlled light conditions (L, light D, dark 12L:12D, LD conditions 12D:12D, DD conditions). Behaviors of these two species were continuously recorded for 9 to 10 days. Under LD conditions, O. laqueus were active for 7 to 14 min during daytime and 298 to 339 min at night, and under DD conditions, for 97 to 140 min during daytime and 71 to 169 min at night. A. aculeatus were active for 49 to 99 min during daytime and 138 to 185 min at night under LD conditions, whereas under DD conditions, they were active for 36 to 56 min during daytime and 55 to 154 min at night. Continuous duration for activity cycles was 39 ± 7.6 h under LD conditions and 42 ± 2.6 h under DD conditions in O. laqueus, and 38 ± 7.4 h under LD conditions and 42 ± 2.8 h under DD conditions in A. aculeatus. Ratios for active duration to inactive duration did not differ between LD condition and DD condition both in O. laqueus and A. aculeatus.

• Access this article

  DOI

Environmental enrichment affects the ontogeny of learning, memory, and depth perception of the pharaoh cuttlefish Sepia pharaonis.

Yasumuro H, Ikeda Y

Zoology (Jena, Germany) ( Elsevier GmbH )  128   27 - 37   2018.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

　View Summary

We investigated the effects of environmental enrichment on the cognitive abilities of pharaoh cuttlefish, Sepia pharaonis, which were reared from day seven in four different environments: isolated, poor, standard, and enriched. First, we used “prawn-in-the-tube” to test whether environmental enrichment affects the ontogeny of learning and memory of S. pharaonis. The results showed that cuttlefish could usually learn the task regardless of their age and environment. At early age (74 – 81 d), cuttlefish from the isolated environment memorized the task for 24 h. However, at later age (104 – 171 d), the isolated cuttlefish were unable to remember the task. In addition, cuttlefish from the poor environment could not memorize the task at all ages examined. Cuttlefish from the standard environment could memorize the task in later ages (134 – 171 d). In contrast, cuttlefish from the enriched environment could memorize the task at all ages examined. Second, we examined the effect of environmental enrichment on the ontogeny of depth perception of S. pharaonis by observing their hunting behavior. Distance from the prey during hunting was always greater in isolated cuttlefish than those from the other three environments. In addition, hunting success and number of prey captured were always lowest in the isolated cuttlefish for all ages. In contrast, hunting success was always the highest in cuttlefish from the enriched environment. These variations in behavior among cuttlefish raised in different environments suggest that the visual/tactic input derived from social and physical factors of the surrounding environment could promote maturation of learning, memory, and depth perception in S. pharaonis.

• Access this article

  DOI
• Search related information
  PubMed

Visual Stimuli for the Induction of Hunting Behavior in Cuttlefish Sepia pharaonis.

Shinzato S, Yasumuro H, Ikeda Y

The Biological bulletin ( Biological Bulletin )  234 ( 2 ) 106 - 115   2018.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

• Access this article

  DOI
• Search related information
  PubMed