Wild birds, in particular waterfowl, are common reservoirs of low pathogenic avian influenza viruses, and infected individuals could spread the viruses during migrations. We used satellite telemetry to track the spring migration of the mallard ducks (Anas platyrhynchos) that winter in Japan. We studied their migration routes, distribution of stopover and breeding sites, and timing of migration movements. We tracked 23 mallards from four different wintering sites. Nine of the 23 mallards reached presumable breeding sites, where migration terminated. The migration routes of the birds greatly differed not only among the wintering sites but also within the same wintering site, although the general feature of the routes was shared among birds within the same wintering site. The mallards used several stopover sites, and they typically stayed for a long period (about one to four weeks) at a site between migration intervals of two to three days. Stopover sites were located in northeast Japan, the eastern coastline of South Korea and North Korea, and the interior of Far Eastern Russia. Mallards from three different wintering sites used a stopover area near the middle part of the Ussuri river in Russia. The terminal sites, which were presumably also breeding sites, were distributed widely over northeast Asia and Far Eastern Russia. These results suggest that mallards that winter in Japan originate from breeding areas widely distributed across eastern Asia. Mallards could potentially transmit avian influenza viruses between Japan and a broad region of northeastern Asia.

The Bonin Islands White-eye, Apalopteron familiare, is the sole endemic avian species surviving on the Bonin Islands. The current distribution of this species is limited to only three islands of the Hahajima Island group: Hahajima, Imotojima, and Mukohjima. Imotojima and Mukohjima, which are small satellite islands of Hahajima, are about 3.6 km and 5.5 km, respectively, from the larger island. To investigate genetic and morphological differences among A. familiare populations on these islands, we assayed 634 bp of mitochondrial control region sequence for 132 birds from five locations among the three islands. We detected five haplotypes: two endemic haplotypes each on Hahajima and Imotojima and one on Mukohjima. Principal component analysis based on eight morphological characters of 162 birds from the three island populations revealed that birds from the small satellite islands had significantly different beak morphological characters. Our findings indicate that over-sea dispersal is rare in A. familiare, even when islands are separated by only a few kilometers, and suggest that little movement occurs on Hahajima. Thus, each population on each island should be conserved as an evolutionarily significant unit. The low dispersal ability of this species suggests that it is vulnerable to habitat fragmentation. Although the populations are currently stable and do not require rapid countermeasures, they should be monitored, especially those on the smaller islands.

We collected Chinese cobras (Naja atra) from one island (Dinghai) and four mainland (Huangshan, Lishui, Quanzhou, and Baise) populations in southeastern China, and used sequence data derived from the ND2 (1032 bp) and cytochrome b (1117 bp) genes and molecular variance estimates to investigate the population genetic structure of the species. Our sequence data show that: (1) the three eastern (Dinghai, Huangshan, and Lishui) populations are genetically segregated from the two southern (Quanzhou and Baise) populations; (2) the Quanzhou and Baise populations consist of two well-defined subclades, suggesting that the two populations have been well differentiated; (3) N. atra from the Huangshan population do not differ from those from the Lishui population, and lineage sorting in the northeastern part of the cobra’s distributional range has not yet been completed because of the young age of Zhoushan Islands. The three eastern populations, the Quanzhou population, and the Baise population should be regarded as different management units (MUs). For these MUs, we suggest that in-situ protection measures should be taken because of their genetic uniqueness. Re-introductions or translocations are required to protect or re-establish natural populations of N. atra, but great care should be taken to enhance or retain local genetic variation.

Because of their complex life styles, amphibians and reptiles living in wetlands require both aquatic and terrestrial buffer zones in their protected conservation areas. Due to steep declines in wild populations, the gold-spotted pond frog (Rana chosenica) is listed as vulnerable by the IUCN. However, lack of data about its movements and use of habitat prevents effective conservation planning. To determine the habitat use and home range of this species, we radio-tracked 44 adult frogs for 37 days between 10 July and 4 Nov. 2007 to observe three different populations in the breeding season, non-breeding season, and late fall. The gold-spotted pond frog was very sedentary; its daily average movement was 9.8 m. Frogs stayed close to breeding ponds (within 6.6 m), and did not leave damp areas surrounding these ponds, except for dormancy migration to terrestrial sites such as dried crop fields. The average distance of dormancy migration of seven frogs from the edge of their breeding ponds was 32.0 m. The average size of an individual’s home range was 713.8 m² (0.07 ha). The year-round population home range, which accounts for the home ranges of a population of frogs, was determined for two populations to be 8,765.0 m² (0.88 ha) and 3,700.9 m² (0.37 ha). Our results showed that to conserve this endangered species, appropriately sized wetlands and extended terrestrial buffer areas surrounding the wetlands (at least 1.33 ha, diameter 130 m) should be protected.

Aeolosomatidae are cosmopolitan meiofaunal Annelida characterised by small size and almost exclusively asexual reproduction. This study is the first report on the chromosome morphology of two aeolosomatid species. Giemsa staining and propidium iodide labelling were performed. The somatic chromosome number of Aeolosoma viride was 2n=30 with many biarmed elements, whereas A. hemprichi showed 60 small chromosomes with a dot-like appearance. Asexual reproduction, with its clonal transmission of chromosomal repatternings, probably ensures the fixation of new karyotypes in species of Aeolosoma.

Vitellogenin (VTG), a yolk-precursor protein in oviparous vertebrates, is a useful biomarker for reproductive physiology and environmental estrogenic pollution. To examine interspecific applicability of an enzyme-linked immunosorbent assay (ELISA) for quantifying Chinemys reevesii VTG, we observed cross-reactivity between a polyclonal antibody against Chinemys reevesii VTG and the VTGs from other turtle species: Chelydra serpentina (Chelydridae), Macrochelys temminckii (Chelydridae), and Pelodiscus sinensis (Trionychidae), which are phylogenetically distant from Chinemys reevesii (Geoemydidae). The VTGs of the three species were induced by injecting estradiol 17β into the turtles and purified by using the EDTA-MgCl₂ precipitation method. The purified VTG appeared as a 200-kDa protein in sodium dodecylsulfate polyacrylamide gel electrophoresis, indicating that the molecular mass of the VTGs of the three species was similar to that of Chinemys reevesii VTG. The purified VTGs were serially diluted (0.004–2 μg/ml) and applied to the ELISA. Although the VTGs of the two chelydrid turtles showed cross-reactivity in a concentration-dependent manner, the degree of cross-reactivity was only 22.8–41.2% (mean=30.0%) and 19.7–53.0% (mean=33.2%) for Chelydra serpentina VTG and Macrochelys temminckii VTG, respectively. The ELISA may therefore be theoretically applicable to measure relative levels of the VTGs of these two species, but the absolute concentration values may be inaccurate. Pelodiscus sinensis VTG showed almost no cross-reactivity (8.0–9.7%, mean=8.9%) at any concentration tested, thus indicating the inapplicability of the ELISA to quantify Pelodiscus sinensis VTG. There are thus limitations in extending the applicability of the ELISA across species, even within the order Testudines.

The proteoglycan aggregate of the cartilage is composed of aggrecan, link protein (LP), and hyaluronan, providing resistance to compression in joints and cartilage structures. To further understand the function of LP during the process of chondrogenesis and bone formation in zebrafish, we cloned the zebrafish cDNA for hyaluronan and proteoglycan link protein 1 (crtl1/hapln1) and examined the expression of the gene during embryogenesis using in-situ hybridization. crtl1/hapln1 expression is first observed in the adaxial cells at the bud- stage. Throughout somitogenesis, crtl1/hapln1 is expressed in the sclerotomes, floor plate, and hypochord. In addition, crtl1/hapln1 is expressed in rhombomeres 3 and 5, pharyngeal arches, telecephalon, otic vesicles, and pectral fins. During chondrocranial/skull formation, crtl1/hapln1 expression is highest at around 4 dpf and is colocalized with aggrecan in the cartilaginous arches and with dermacan in the dermal bones.

New probable mechanosensory cell groups were found in Polyandrocarpa misakiensis. In this species, the tunic with epithelium penetrates into the oral and atrial tentacles (oral and atrial tentacular tunic), which is continuous with a tunic layer intervening between the descending and ascending epithelium of the siphons. In the oral tentacles, the tunic only extends into the basal part, but in the atrial siphon the tunic extends the full length of the tentacle. Intraepithelial sensory cells were found in the basal part of the oral and atrial tentacular tunic. These sensory cells are usually solitary or paired in the atrial tentacles, and a few cells are grouped together in the oral tentacles. In the oral tentacles, the apicolateral parts of the sensory cells are joined together by two types of junctions, i.e., adherent junctions and modified tight junctions. The supporting cells and sensory cells are connected by adherent junctions. Certain sensory cells are coupled to what seem to be neurosecretory cells. The sensory cells have one apical cilium surrounded by microvilli and a basal axonal process. The apical cytoplasm of the sensory cells has a few organelles. The basal cytoplasm of the sensory cells is dense with rough endoplasmic reticulum, mitochondria, lipid droplets, and dense bodies. The morphology of these sensory cells is comparable with that of the ciliated intraepithelial sensory neurons found in many tunicates, such as those of cupular organ and capusular organ.

Wind-sensitive giant interneurons (GIs) in the cricket Gryllus bimaculatus show functional recovery after unilateral cercal ablation. Physiological properties such as threshold velocity and response magnitude (number of action potentials elicited) of GIs 8-1, 9-1, 9-2 and 9-3 to an air puff stimulus were investigated in crickets reared under the condition that permitted free walking for 6 days after unilateral cercal ablation (“6-day-free” crickets). The results were compared to those previously obtained from crickets 1 day after unilateral cercal ablation (“1-day-free” crickets) to clarify functional changes during an early 5-day period after the sensory deprivation. Each GI showed a large functional change, despite the short period after the ablation. However, the degree of physiological change was different from one GI to another and from one stimulus direction to another. The direction at which the GIs showed physiological change during the 5-day period coincided well with that at which the GIs received excitatory sensory inputs from filiform hairs on the remaining cercus. It seems that the synaptic connection or efficacy between sensory neurons of filiform hairs with particular directionality on the one remaining cercus and GIs increased during the 5-day recovery period.

Follicle rupture during ovulation is a well-regulated biological process of extracellular matrix degradation in the vertebrate ovary. Although proteolytic enzymes responsible for the rupture have recently been identified in the medaka, Oryzias latipes, the lack of knowledge about the ovarian expression and distribution of extracellular matrix components in lower vertebrates prevents the understanding of this process’s molecular mechanism. To approach the problem, we cloned a cDNA coding for the medaka collagen type-I α1 chain and examined its mRNA expression in the fish ovary. The deduced amino acid sequence of the collagen type-I α1 chain was homologous to those of the proteins from other vertebrate species. The α1 chain mRNA was expressed in various tissues of the adult fish. In the ovary sections of mature female fish, this mRNA was detected in a line surrounding ovarian follicles of all sizes. A comparison with the distribution of gelatinase B mRNA in follicles that had just ovulated indicated that the collagen type-I α1 gene is expressed in the theca cells. The current results strongly suggest that collagen type I is synthesized by theca cells and is localized in the same cell layer of the follicles.

A new species of mudskipper (Gobiidae: Oxudercinae) from northern Australia is described. This species was previously misidentified as P. novaeguineaensis Eggert, 1935. Periophthalmus takita sp. nov. can be distinguished from its congeners by the following suite of characters: modally VIII spines in the first dorsal fin; second dorsal and anal fins with I, 11–12 rays; shape and color pattern of the first and second dorsal fins; and the extent of fusion between the two innermost rays of the pelvic fin. A re-diagnosis of P. novaeguineaensis is provided, as well as a revised key to the genus Periophthalmus.