start-ver=1.4 cd-journal=joma no-vol=205 cd-vols= no-issue=22 article-no= start-page=3487 end-page=3504 dt-received= dt-revised= dt-accepted= dt-pub-year=2002 dt-pub=200211 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Hatching controlled by the circatidal clock, and the role of the medulla terminalis in the optic peduncle of the eyestalk, in an estuarine crab Sesarma haematocheir en-subtitle= kn-subtitle= en-abstract= kn-abstract=Embryos attached to the female crab Sesarma haematocheir hatch synchronously within 1 h. Hatching is also synchronized near the time of the expected nocturnal high tide. These events are governed by a single circatidal clock (or pacemaker) in the female crab. The present study examined the role of the optic peduncle of the eyestalk on hatching and hatching synchrony. Surgery was performed either from the tip of the eyestalk [to remove the region of the optic peduncle from the compound eye–retina complex to the medulla interna (MI)] or from a small triangle 'window' opened on the eyestalk exoskeleton [to create lesions on the medulla terminalis (MT) of the optic peduncle]. Neither hatching nor hatching synchrony was affected by removal of the region of the optic peduncle from the compound eye–retina complex to the MI: the circatidal rhythm also remained. Removal of the MI probably caused damage to the sinus gland and the bundle of axons running from the sinus gland to the X organ. Nevertheless, maintenance of highly synchronized hatching indicates that the X organ–sinus gland system is not related to hatching. Hatching and hatching synchrony were not affected by dorsal-half cuts of the MT: the timing of hatching was not affected either. By contrast, transverse and ventral-half cuts of the MT caused severe damage to most females; hatching of many females was suppressed, while hatching of some females was either periodic, at intervals of approximately 24 h, or arrhythmic for a few days. The bundle of neuronal axons is tangled in the MT, and the axons inducing hatching pass through the ventral half of the MT. Complete incision of these axon bundles may have suppressed hatching. Incomplete incision of the axon bundle or partial damage to the neurons may have caused periodic or arrhythmic patterns of hatching. There are two possible roles for MT in hatching. One possibility is that neurons in the MT only induce hatching under the control of the circatidal pacemaker located in a site somewhere other than the optic peduncle. Another possibility is that the circatidal pacemaker is actually present in the MT. The second possibility seems more plausible. Each embryo has a special 48–49.5 h developmental program for hatching. This program could be initiated by the circatidal pacemaker in the female, and hatching synchrony may also be enhanced by the same pacemaker. en-copyright= kn-copyright= en-aut-name=SaigusaMasayuki en-aut-sei=Saigusa en-aut-mei=Masayuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=Laboratory of Behavior and Evolution, Graduate School of Natural Science and Technology, Okayama University en-keyword=circatidal pacemaker kn-keyword=circatidal pacemaker en-keyword=estuarine crab kn-keyword=estuarine crab en-keyword=gentle-release kn-keyword=gentle-release en-keyword=behavior kn-keyword=behavior en-keyword=hatching synchrony kn-keyword=hatching synchrony en-keyword=medulla terminalis kn-keyword=medulla terminalis en-keyword=optic peduncle kn-keyword=optic peduncle en-keyword=eyestalk kn-keyword=eyestalk en-keyword=neuronal pathway kn-keyword=neuronal pathway en-keyword=vigorous-release behavior kn-keyword=vigorous-release behavior en-keyword=Sesarma kn-keyword=Sesarma en-keyword=haematocheir. kn-keyword=haematocheir. END start-ver=1.4 cd-journal=joma no-vol=207 cd-vols= no-issue=4 article-no= start-page=621 end-page=632 dt-received= dt-revised= dt-accepted= dt-pub-year=2004 dt-pub=20042 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Purification and cDNA cloning of the ovigerous-hair stripping substance (OHSS) contained in the hatch water of an estuarine crab Sesarma haematocheir en-subtitle= kn-subtitle= en-abstract= kn-abstract=

The egg attachment system of an estuarine crab Sesarma haematocheir is formed on the maternal ovigerous hairs just after egg laying, and slips off these hairs just after hatching. The stripping is caused by an active factor that we call OHSS (ovigerous-hair stripping substance), which is released by the embryo upon hatching. OHSS was purified, and its active form had a molecular mass of 25·kDa. The cDNA of OHSS cloned from an embryonic cDNA library was 1759·bp long, encoding 492 amino acids in a single open reading frame (ORF). The C-terminal part of the predicted protein was composed of a trypsin-like serine protease domain, with homology to counterparts in other animals of 33–38%. The predicted protein (54.7·kDa) secreted as a zymogen may be cleaved post-translationally, separating the Cterminal from the N-terminal region. The OHSS gene was expressed in the embryo at least 2 weeks before hatching. Expression was also detected in the zoea larva 1 day after hatching and in the brain of the female. However, it was not detected in the muscle, hepatopancreas or ovigerous seta of the female. Ultrastructural analysis indicated that the material investing maternal ovigerous hair, i.e. the outermost layer (E1) of the egg case, is attached at the special sites (attachment sites) arranged at intervals of 130–160·nm on the hair. It is suggested that OHSS acts specifically at these sites, lysing the bond with the coat, thus disposing of the embryo attachment system. This enables the female to prepare the next clutch of embryos without ecdysis.

en-copyright= kn-copyright= en-aut-name=GusevOleg en-aut-sei=Gusev en-aut-mei=Oleg kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IkedaHideki en-aut-sei=Ikeda en-aut-mei=Hideki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=OkochiTetsushi en-aut-sei=Okochi en-aut-mei=Tetsushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=LeeJae Min en-aut-sei=Lee en-aut-mei=Jae Min kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HatakeyamaMasatsugu en-aut-sei=Hatakeyama en-aut-mei=Masatsugu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KobayashiChiyoko en-aut-sei=Kobayashi en-aut-mei=Chiyoko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=AgataKiyokazu en-aut-sei=Agata en-aut-mei=Kiyokazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=YamadaHidenori en-aut-sei=Yamada en-aut-mei=Hidenori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=SaigusaMasayuki en-aut-sei=Saigusa en-aut-mei=Masayuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama Univeristy affil-num=4 en-affil= kn-affil=National Institute of Agrobiological Sciences affil-num=5 en-affil= kn-affil=National Institute of Agrobiological Sciences, Owashi affil-num=6 en-affil= kn-affil=RIKEN, Hyougo affil-num=7 en-affil= kn-affil=RIKEN, Hyougo affil-num=8 en-affil= kn-affil=Okayama Univresity affil-num=9 en-affil= kn-affil=Okayama University en-keyword=crab kn-keyword=crab en-keyword=Sesarma (or Chiromantes) haematocheir kn-keyword=Sesarma (or Chiromantes) haematocheir en-keyword=ovigerous hair kn-keyword=ovigerous hair en-keyword=embryo attachment system kn-keyword=embryo attachment system en-keyword=investment coat kn-keyword=investment coat en-keyword=stripping kn-keyword=stripping en-keyword= ovigerous-hair stripping substance (OHSS) kn-keyword= ovigerous-hair stripping substance (OHSS) en-keyword= serine protease. kn-keyword= serine protease. END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue= article-no= start-page=33 end-page=37 dt-received= dt-revised= dt-accepted= dt-pub-year=1988 dt-pub=198804 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=海産生物における実験動物化について思うこと en-subtitle= kn-subtitle= en-abstract= kn-abstract= en-copyright= kn-copyright= en-aut-name=SaigusaMasayuki en-aut-sei=Saigusa en-aut-mei=Masayuki kn-aut-name=三枝誠行 kn-aut-sei=三枝 kn-aut-mei=誠行 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学教養部自然系 END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue= article-no= start-page=6 end-page=12 dt-received= dt-revised= dt-accepted= dt-pub-year=1992 dt-pub=199206 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=瀬戸内の森と林―自然林の生育とその生態的機能を考える― en-subtitle= kn-subtitle= en-abstract= kn-abstract= en-copyright= kn-copyright= en-aut-name=SaigusaMasayuki en-aut-sei=Saigusa en-aut-mei=Masayuki kn-aut-name=三枝誠行 kn-aut-sei=三枝 kn-aut-mei=誠行 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学教養部自然系 END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=9 end-page=18 dt-received= dt-revised= dt-accepted= dt-pub-year=2002 dt-pub=20020920 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Sedimentary environments of mangrove swamp in the Funaura Bay, Iriomote Island, Okinawa Prefecture, Southwest Japan kn-title=西表島船浦湾におけるマングローブ干潟の堆積環境 ―堆積物と生物遺骸の保存状況について― en-subtitle= kn-subtitle= en-abstract= kn-abstract=The distribution of conch shell contained in clastic sediments in the mangrove swamps in the Funaura Bay, Iriomote Island, Okinawa Prefecture was studied. The sediments in the mangrove swamp are mainly composed of up to 90% sands. The sand clasts are inferred to be derived from the sandstone of Miocene Yaeyama Group. The conch shells are richer in the muddy fraction than the sandy fraction. Many Terebralia palustris inhabit the mangrove swamp. However few dead shells were also observed in the sediments. Effect of selective transportation hermit crabs is considered to be the cause of this distribution. en-copyright= kn-copyright= en-aut-name=AzumaHiroyuki en-aut-sei=Azuma en-aut-mei=Hiroyuki kn-aut-name=東裕行 kn-aut-sei=東 kn-aut-mei=裕行 aut-affil-num=1 ORCID= en-aut-name=SaigusaMasayuki en-aut-sei=Saigusa en-aut-mei=Masayuki kn-aut-name=三枝誠行 kn-aut-sei=三枝 kn-aut-mei=誠行 aut-affil-num=2 ORCID= en-aut-name=FukudaHiroshi en-aut-sei=Fukuda en-aut-mei=Hiroshi kn-aut-name=福田宏 kn-aut-sei=福田 kn-aut-mei=宏 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=The Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Department of Biology, Faculity of Science, Okayama University affil-num=3 en-affil= kn-affil=Faculity of Agriculture, Okayama University en-keyword=conch shell kn-keyword=conch shell en-keyword=Mangrove swamp kn-keyword=Mangrove swamp en-keyword=Terebralia palustris kn-keyword=Terebralia palustris END