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Cetaceans accumulate high levels of environmental pollutants, yet their toxicological studies have been difficult due to technical and ethical issues. It is essential to identify and fill the curre...

Whales accumulate high levels of environmental pollutants. Exposure to polychlorinated biphenyls (PCBs) and their metabolites (OH-PCBs) could be linked to abnormal behavior, which may lead to mass stranding of marine mammals. Whales may thus suffer from adverse effects such as neuronal dysfunction, yet testing the neurotoxicity of these compounds has never been feasible for these species. This study established neurons chemically reprogrammed from fibroblasts of mass stranded melon-headed whales (Peponocephala electra) and used them for in vitro neurotoxicity assays. Exposure to 4-hydroxy-2',3,5,5'-tetrachlorobiphenyl (4'OH-CB72), a metabolite of PCBs, caused apoptosis in the reprogrammed neurons. Transcriptome analysis of 4'OH-CB72-treated whale neurons showed altered expressions of genes associated with oxidative phosphorylation, chromatin degradation, axonal transport, and neurodegenerative diseases. These results suggest that 4'OH-CB72 exposure may induce neurodegeneration through disrupted apoptotic processes. A comparison of the results with human reprogrammed neurons revealed the specific effects on the whale neurons. Our noninvasive approach using fibroblast-derived neurons is useful for hazard and risk assessments of neurotoxicity in whales.

Totally laparoscopic gastrectomy (TLG), which involves a complete intracorporeal gastric transection and the creation of an anastomosis, has been gradually adopted. However, a potential limitation of intracorporeal transection is the lack of tactile feedback, and whether this limitation influences oncological outcomes is unclear. The aim of this study is to evaluate the short- and long-term oncological safety of TLG using endoscopy-guided intracorporeal gastric transection for clinical stage (cStage) I gastric cancer. A total of 1875 consecutive patients who underwent laparoscopic gastrectomy for cStage I gastric cancer between January 2007 and March 2015 were enrolled in this study. Marking clips were preoperatively placed and a transection line was determined by perceiving it tactually in laparoscopy-assisted gastrectomy (LAG) or endoscopically in TLG. After propensity score matching, 1366 patients (683 each for LAG and TLG groups) were selected to primarily test the non-inferiority of TLG to that of LAG for relapse-free survival (RFS). In the propensity-matched population, the 5-year RFS rates of the LAG and TLG groups were 94.3% (95% confidence interval (CI) 92.2–95.8%), and 95.6% (95% CI 93.8–96.9%), respectively. The hazard ratio (TLG/LAG) was 0.77 (95% CI 0.48–1.24, P for non-inferiority

The spinal nerves supplying the wing membranes of Japanese little horseshoe bats, Rhinolophus cornutus were studied. The wing membrane was innervated by nerve branches of the radial, ulnar, and median nerves, showing that the membrane was formed from the skin of the forelimb rather than that of the thoracolumbar skin. The radial nerve was mainly composed of the ventral rami of C7-T1, the ulnar nerve by C8-T2, and the median nerve by C8-T1. These components of R. cornutus tended to be from a narrower range of spinal nerves and to position more caudally than those of humans. In addition, the ulnar nerve showed a distribution pattern different from that of other mammals.

A total of 62 skulls from two herds of melon-headed whales stranded on Japanese coasts were examined. Although the species originally had around 22 teeth in each tooth row, older specimens (30–35 years old) possessed only an average of 9.2 teeth on each side of the upper jaw. Significant shortening of the root caused the tooth loss observed in this species. In addition, we observed the following trends with respect to the pattern of tooth loss: (1) teeth are lost from the posterior to the anterior part of the tooth row, (2) the loss of teeth in the upper jaw precedes that in the lower jaw, and (3) tooth count decreases with age. The above-mentioned tendencies were found in both herds. Bony tissues at the alveoli seem to push out the teeth: the bottom of the tooth socket rises both during the root-shortening process and after the tooth falls out. There were no signs of accidental tooth loss such as resorption of alveolar bones due to gingival disease or injuries on alveolar bones by physical impacts. Therefore, the postnatal tooth count decrease is considered an ontogenetic event of this species. The ontogenetic decrease in tooth count coincides with the tendency of evolutionary tooth number reduction in odontocetes at two particular points, the secondary reduction from polyodontia and the more progressed decrease in teeth in the upper jaw than in the lower jaw. Therefore, the evolutionary tooth count reduction seems to be repeated in the lifetime of the melon-headed whale.

Oxidosqualene cyclases (OSCs) catalyze the cyclization of an acyclic substrate into various polycyclic triterpenes through a series of cation-π cyclization and 1,2-rearrangement processes. The mechanisms by which OSCs control the fate of intermediate carbocation to generate each specific triterpene product have not yet been determined. The formation of ubiquitous sterol precursors in plants, cycloartenol and Cucurbitaceae-specific cucurbitadienol, only differs by the extent of the 1,2-rearrangement of methyl and hydride. In the present study, we identified critical residues in cycloartenol synthase and cucurbitadienol synthase that were primarily responsible for switching product specificities between the two compounds. The mutation of tyrosine 118 to leucine in cycloartenol synthase resulted in the production of cucurbitadienol as a major product, while the mutation of the corresponding residue leucine 125 to tyrosine in cucurbitadienol synthase resulted in the production of parkeol. Our discovery of this "switch" residue will open up future possibilities for the rational engineering of OSCs to produce the desired triterpenes.

The genus Mesoplodon (Cetacea: Odontoceti: Ziphiidae) is one of the few cetacean genera with the karyotype 2n = 42. The 2n = 42 karyotype of M. europaeus and M. carlhubbsi is largely consistent with the general cetacean karyotype 2n = 44, although other 2n = 42 karyotypes do not exhibit clear homologies with the general cetacean karyotype. Therefore, the chromosomes of Mesoplodon species may be the key to understanding cetacean karyological evolution. In the present study, the male karyotypes of M. stejnegeri and M. carlhubbsi were examined. In both species, the diploid number of the male karyotype was 42. Both species had the following characteristics: 1) a huge subtelocentric X chromosome with a large C-block; 2) a small metacentric Y chromosome; 3) nucleolus organizer regions (NORs) in the terminal regions of a large autosome and one or two small metacentric autosomes; 4) small metacentric autosomes; 5) large submetacentric and subtelocentric autosomes; 6) less accumulated C-heterochromatin in the centromeric region; and 7) heteromorphism in C-heterochromatin accumulation between homologues. Characteristics 1 and 3 are peculiar to only the karyotypes of Mesoplodon species, whereas characteristics 4, 5, 6, and 7 are also found in the species with the general cetacean karyotype 2n = 44.

Pool-based batch active learning is aimed at choosing training inputs from a 'pool' of test inputs so that the generalization error is minimized. P-ALICE (Pool-based Active Learning using Importance-weighted least-squares learning based on Conditional Expectation of the generalization error) is a state-of-the-art method that can cope with model misspecification by weighting training samples according to the importance (i.e., the ratio of test and training input densities). However, importance estimation in the original P-ALICE is based on the assumption that the number of training samples to gather is small, which is not always true in practice. In this paper, we propose an alternative scheme for importance estimation based on the inclusion probability, and show its validity through numerical experiments.

Birds have long been considered indicator species of biodiversity and so ecologists use them as indices of abundance and diversity in order to assess environmental health. These indices are based on surveys which assess the number of species and number of individuals counted in an area over a set time. We can modify citizen science approaches as a way to increase the involvement of undergraduate students in research. However, undergraduate students may have little experience in ecological surveying. Therefore, we tested whether bird counts collected by inexperienced undergraduates were consistent and repeatable among observers. We also examined bird communities at three sites of different size in and around Kyoto University in Kyoto Prefecture. First, we found that there was a high level of consistency among inexperienced observers. We also found a positive relationship between urban park size and avian abundance and diversity. Finally, we found that the bird communities at the two larger sites were most similar to one another whilst the community at the smallest site was quite distinct from the two larger sites. Therefore, this study shows that using citizen science methods may be an effective tool for gathering meaningful scientific data with inexperienced undergraduate observers.

We measured 145 bottlenose dolphin skulls to examine the effects of size on skull shape. We found that the rostral length and the width of the temporal fossa showed highly positive allometry. These differences, as a result of size, reflect the growth of the feeding apparatus. The positive allometry of the rostral length implies an extension of the range for food catching and an increase in mouth-closing speed. The positive allometry of the temporal fossa width reflects the development of the temporal muscle. On the other hand, the positive allometry of both the rostral length and the temporal fossa width seem to indicate a contradictory effect on occlusal force. However, the occlusal force estimated by bony characters increased by the condylobasal length. These trends were observed not only in immature specimens but also in mature specimens of different sizes. This fact means that the change of the skull shape in immature specimens is caused by the development of the feeding apparatus, while tha...

We examined the skulls of 72 bottlenose dolphins from the Indian and western Pacific Oceans to clarify the systematics in genusTursiops. We also examined type skulls ofTursiops aduncus (Ehrenberg, 1832),T. eurynome (Gray, 1846),T. catalania (Gray, 1862),Delphinus (Steno) gadamu Owen 1866,T. dawsoni Lydekker 1908, andT. truncatus (Montagu, 1821). The specimens were divided into two groups, A and B, based on rostrum length and characters of the basal part of the rostrum. The rostrum of group A was longer and tapered abruptly near the base, whereas that of group B was shorter and tapered more gradually throughout its length. Group A contained specimens from western, central, and eastern Asia, Africa, and Australasia. Group B contained specimens from central and eastern Asia and Australasia. The six type skulls were also clearly divided into two groups; the type skulls ofT. aduncus, T. catalania, andDelphinus (Steno) gadamu were included in group A, whereas the type skulls ofT. truncatus, T. eurynome, andT. dawsoni were included in group B. This grouping was consistent with the genetic status. Therefore, we identified group A specimens asT. aduncus and group B specimensT. truncatus, the oldest scientific names related to the two groups.

We analyzed the skulls of 27 bottlenose dolphins (Tursiops spp.) from the waters around Japan to clarify their systematics. We divided the Japanese bottlenose dolphins into two morphological groups. Group A was comprised of six specimens from the coastal waters of the Amami Islands, Amakusa-Shimoshima Island, and Mikura Island. Group B included 21 specimens from other waters around Japan. Comparisons with type specimens showed that Groups A and B were identical to the types of T. aduncus and T. truncatus, respectively. These results support previous molecular studies on some specimens identified as T. aduncus.

The condition of mtDNA in hair shafts preserved in a museum was examined using 30 study skins of masked palm civets, Paguma larvata (Viverridae), collected between 1924 and 2011. Comparisons of extracts from fresh and burnt alum-fixed hair shafts showed that burnt alum, which is commonly used in taxidermy, had no harmful effect on the amount of total DNA and lengths of the mtDNA fragments. Burnt alum-fixed hair shafts had a tendency to develop a small degree of melanin hindering PCR amplification compared with fresh hair shafts, although that observation was not supported statistically (Wilcoxon signed-rank test, Z = -0.183, P = 0.855). However, the amount of total DNA decreased after preparation of specimen in an exponential relation (regression of log DNA amount with year, regression analysis, F = 7.065, P = 0.013). Nevertheless, the oldest specimen, collected in 1924, yielded 1341.5 ng of DNA per 100 hair shafts, which was sufficient for PCR amplification. In addition, the mtDNA fragment length and amount of melanin in the hair shaft were not significantly correlated with the passage of time after preparation (F = 0.244, P = 0.625 for mtDNA fragment length; F = 0.039, P = 0.845 for the amount of melanin). Therefore, hair shafts prepared and preserved by chemical treatment in museums are good sources of mtDNA and useful for genetic analysis.

We investigate the $\ensuremath{\alpha}+d$ elastic scattering and the radiative capture reaction of ${}^{2}$H(${\ensuremath{\alpha},\phantom{\rule{-0.16em}{0ex}}\ensuremath{\gamma})}^{6}$Li based on the $\ensuremath{\alpha}$ + $p$ + $n$ three-body model. The $\ensuremath{\alpha}+d$ scattering states are described by using the complex-scaled solutions of the Lippmann-Schwinger equation. We calculate the elastic phase shifts for the $\ensuremath{\alpha}+d$ scattering and the radiative capture cross section of ${}^{6}$Li. We evaluate the contributions of the $\ensuremath{\alpha}$ + $p$ + $n$ structures in those observables. It is found that in the $\ensuremath{\alpha}+d$ scattering process, the deuteron breakup and the rearrangement to the ${}^{5}$He $+$ $p$ and ${}^{5}$Li $+$ $n$ channels play prominent roles in reproducing the observed phase shifts and radiative capture cross section.

The local model fitting (LMF) method is one of the useful single-shot surface profiling algorithms. The measurement principle of the LMF method relies on the assumption that the target surface is locally flat. Based on this assumption, the height of the surface at each pixel is estimated from pixel values in its vicinity. Therefore, we can estimate flat areas of the target surface precisely, whereas the measurement accuracy could be degraded in areas where the assumption is violated, because of a curved surface or sharp steps. In this paper, we propose to overcome this problem by weighting the contribution of the pixels according to the degree of satisfaction of the locally flat assumption. However, since we have no information on the surface profile beforehand, we iteratively estimate it and use this estimation result to determine the weights. This algorithm is named the iteratively-reweighted LMF (IRLMF) method. Experimental results show that the proposed algorithm works excellently.