The Evolution of Unusually Small Amelogenin Genes in Cetaceans; Pseudogenization, X-Y Gene Conversion, and Feeding Strategy.

Among extant cetaceans, mysticetes are filter feeders that do not possess teeth and use their baleen for feeding, while most odontocetes are considered suction feeders, which capture prey by suction without biting or chewing with teeth. In the present study, we address the functionality of amelogenin (AMEL) genes in cetaceans. AMEL encodes a protein that is specifically involved in dental enamel formation and is located on the sex chromosomes in eutherians. The X-copy AMELX is functional in enamel-bearing eutherians, whereas the Y-copy AMELY appears to have undergone decay and was completely lost in some species. Consistent with these premises, we detected various deleterious mutations and/or non-canonical splice junctions in AMELX of mysticetes and four suction feeding odontocetes, Delphinapterus leucas, Monodon monoceros, Kogia breviceps, and Physeter macrocephalus, and in AMELY of mysticetes and odontocetes. Regardless of the functionality, both AMELX and AMELY are equally and unusually small in cetaceans, and even their functional AMELX genes presumably encode a degenerate core region, which is thought to be essential for enamel matrix assembly and enamel crystal growth. Furthermore, our results suggest that the most recent common ancestors of extant cetaceans had functional AMELX and AMELY, both of which are similar to AMELX of Platanista minor. Similar small AMELX and AMELY in archaic cetaceans can be explained by gene conversion between AMELX and AMELY. We speculate that common ancestors of modern cetaceans employed a degenerate AMELX, transferred from a decaying AMELY by gene conversion, at an early stage of their transition to suction feeders.

Comparative Morphology of the Lingual Papillae and Their Connective Tissue Cores in the Tongue of Pallas's Squirrel (Callosciurus erythraeus thai, Kloss, 1917).

We observed the morphology of the papilla linguae (filiform, fungiform, foliate, and vallate) and underlying connective tissue cores (CTCs) in Pallas's squirrel (Callosciurus erythraeus thai) using light and scanning electron microscopy. The tongue was caudally elongated and lacked the lingual torus. Filiform papillae were densely distributed along the dorsal surface of the apex, and the rostral and caudal parts of the corpus, but were attenuated in the lingual root. Two or three vallate papillae that were rounded or elongated were situated at the boundary between the caudal part of the corpus and lingual root, and foliate papillae and associated cone-like processes were observable in the lateral margin of the caudal end. The epithelial surface of filiform papillae had a main process and a few associated processes that varied between short and elongated, depending on the location. Filiform papillae CTCs appeared to have a few processes that caudally surrounded a concavity and were morphologically variable based on location. Moreover, fungiform papillae CTCs appeared to be columnar cores and had a shallow convex curve at the top. The Pallas's squirrel's tongue exhibited transitional morphological characteristics between Rodentia and other mammalian species, in that they lacked the lingual torus and had CTCs of lingual papillae that were somewhat morphologically similar to those of other non-Glires species, especially treeshrews and tamarins, rather than those of other Rodentia species.

Comparative morphology of the lingual papillae and their connective tissue cores in the tongue of the American mink, Neovison vison.

We observed the morphology of the lingual papillae (filiform, conical, fungiform, and vallate papillae, and lateral organ) and their connective tissue cores (CTCs) in the American mink (Neovison vison) using light and scanning electron microscopy. Filiform papillae were distributed on the apex linguae and rostral regions of the corpus linguae. Conical papillae were distributed over the caudal region and absent in the radix linguae. Numerous ridges were present in the radix linguae. Four to six vallate papillae were situated at the border between the corpus and radix linguae. Instead of foliate papillae, a pair of lateral organs was situated on the caudal edge of the corpus. The epithelial surface of each filiform papilla consisted of a single main process and 10-12 accessory processes. Notably, filiform papillae in the apex linguae exhibited morphological variation, and some were dome-like and lacked processes. In contrast, filiform papillae on the rostral part were not variable, were extended to a sharp tip, were associated with an eosinophilic stratum corneum, and lacked nuclei. The CTCs of the filiform papillae consisted of a main core and slender accessory cores surrounding a concavity. Those in the apex linguae were similar in appearance and consisted of main and adjacent accessory cores. The fungiform papillae had a dome-like epithelial surface and their CTCs were columnar, with upper concavities and flanges. The simplified lingual morphology of the American mink, particularly in the filiform papillae in the apex linguae, may be influenced by its diet and semiaquatic lifestyle.

Development of active jejunal glucose absorption in broiler chickens.

Growth in chickens, especially meat-type chickens (broilers), is extremely rapid, but studies on the regulatory mechanism of intestinal glucose absorption with growth are few, contradictory, and unclear. Here, we investigated the regulation of intestinal glucose absorption with growth in broiler chickens using oral glucose gavage, intestinal Evans blue transit, intestinal glucose absorption, scanning electron microscopy, and glucose absorption- and cell junction-related gene expression analyses. Peak blood glucose levels after oral glucose gavage occurred at 10 and 50 min in chickens at 1 wk (C1W) and 5 wk (C5W) of age, respectively. The area under the curve for glucose levels was greater for the C5W than the C1W (P = 0.035). The stain ratio in the small intestine in the C5W was lower than that in the C1W (P = 0.01), but there were no differences in the tissue regions stained with Evans blue and the migration distance of Evans blue from Meckel's diverticulum. In everted sac and Ussing chamber experiments, we observed reduced intestinal glucose uptake and electrogenic glucose absorption in the jejunum of the C5W. Phloridzin, an inhibitor of sodium/glucose cotransporter 1 (SGLT1), suppressed the glucose-induced short-circuit current in the C1W (P = 0.016) but not the C5W. Although the addition of NaCl solution stimulated the glucose-induced short-circuit current in the C1W, no differences between the treatments were observed (P = 0.056), which was also the case in the C5W. Additionally, tissue conductance was diminished in the C5W compared with that in the C1W. Moreover, in the C5W, the intestinal tract was more developed and the jejunal villi were enlarged. In conclusion, glucose absorption throughout the intestine could be greater in C5W than in C1W; however, reduced SGLT1 sensitivity, decreased ion permeability, and intestinal overdevelopment lead to decreased local glucose absorption in the jejunum with growth in broiler chickens. These data provide a detailed analysis of intestinal glucose absorption in growing broiler chickens, and can contribute to the development of novel feeds.

The red ruffed lemur, Varecia rubra (É. Geoffroy Saint-Hilaire, 1812): a comparative morphology investigation of lingual papillae and connective tissue cores.

The morphology of the lingual papillae (filiform, foliate, fungiform, and vallate papillae) and the underlying connective tissue core of the red ruffed lemur (Varecia rubra) of a strepsirrhines species were studied using light and scanning electron microscopy. The filiform papillae distributed at the root of the tongue were larger than the structures distributed at the body and apex. Six to eight vallate papillae were arranged in a Y-shape at the border between the lingual body and the lingual root. Foliate papillae were observed at the posterior lateral border of the tongue. Scanning electron microscopy revealed a primary process and numerous auxiliary processes in the epithelial layer of filiform papillae. After epithelial removal, the connective tissue core of the filiform papilla showed several protrusions surrounding an oval-shaped depression that extended slightly posteriorly, and a large, maple-shaped filiform papilla was seen in the posterior portion of the tongue. The connective tissue cores of the fungiform papillae exhibited a longitudinally ridged cylindrical structure. The connective tissue core of the foliate papillae had numerous tubular projections arranged along a groove with a salivary gland conduit at the base. As a Lemuridae species, the appearance of the fungiform and filiform papillae of the red ruffed lemur is similar to that reported in previous studies of the ring-tailed lemur, with some differences, especially in the filiform papillary connective tissue core at the base and tongue body border. These findings suggest the taxonomic and phylogenetic origins of the lemurs as well as the influence of dietary diversity.

Morphological and molecular phylogenetical identification of Tricodectes pinguis from Japanese black bears (Ursus thibetanus japonicus) in Aomori Prefecture, Japan.

Trichodectes pinguis, referred to commonly as the bear-biting louse, has been reported in several bear species. However, graphical (blurred or coarse) and genetic information on the louse is limited. In this study, we identified T. pinguis collected from Japanese black bears in the Aomori Prefecture, Japan. We confirmed 12S rDNA sequences derived from the collected T. pinguis and performed molecular phylogenetic analysis based on 12S rDNA. The analysis revealed the parasitic louse to be T. pinguis. Interestingly, the body size of T. pinguis found in this study was smaller than the previous recorded body size of them in Japan and Turkey. To better understand the biting louse infesting bears, morphometric and genetic information from other bear hosts needs to be accumulated.

Light and scanning electron microscopic study on the tongue and lingual papillae of the common raccoon, Procyon lotor.

We observed the external surface and connective tissue cores (CTCs), after exfoliation of the epithelium of the lingual papillae (filiform, fungiform, foliate and vallate papillae) of the common raccoon (Procyon lotor) using scanning electron microscopy and light microscopy. The tongue was elongated and their two-third width was almost fixed. Numerous filiform papillae were distributed along the anterior two-thirds of the tongue and fungiform papillae were distributed between the filiform papillae. Eight vallate papillae that had a weak circumferential ridge were distributed in a V-shape in the posterior part of the tongue and numerous taste buds were observable in the circumferential furrows of vallate papillae. Weak fold-like foliate papillae were observable at the lateral edge in the posterior part of the tongue and a few salivary duct orifices were observable beneath the foliate papillae. An islet-like structure with numerous taste buds, was observable on the deep part of the salivary duct of foliate papillae. Large conical papillae were distributed at the posterior part and root of the tongue. After removal of epithelium, filiform papillae of CTCs were appeared to be a thumb or cone-like main core and associating several finger-like short accessory cores. These cores were surrounded an oval concavity. The main core was situated behind the concavity and associated with accessory cores. CTCs of fungiform papillae were cylinder-like with numerous vertically running ridges and with a few concavities seen at the top of the cores. CTCs of vallate papillae and their surrounded circumferential ridge were covered with numerous pimple-like protrusions. The lingual papillae of Common raccoon's tongue had morphological feature of carnivore species.

Complete Genome Sequences of Two Strains of Francisella tularensis subsp. holarctica bv. japonica.

Francisella tularensis, a highly infectious bacterium, is the etiological agent of the zoonotic disease tularemia. It is widely distributed in the Northern Hemisphere, including Japan. Here, we have determined the complete genome sequences of two strains of F. tularensis subsp. holarctica bv. japonica isolated from hares in 2008 and 2009.

Avian influenza and Newcastle disease viruses from northern pintail in Japan: isolation, characterization and inter-annual comparisons during 2006-2008.

Since wild ducks constitute a vital element in the epizootiology of avian influenza viruses (AIVs) as well as avian paramyxoviruses (APMVs) and play a key role in the ecology and inter-species transmission of these viruses, it is crucial to elucidate the diversity and prevalence of these viruses within these bird populations. This report shows the presence, antigenic diversity, and inter-annual prevalence variations of AIVs in apparently healthy northern pintail (Anas acta) wintering in Japan. We also provide evidence that this host carries APMV-1: Newcastle disease virus (NDV) and other haemagglutinating viruses. Composite samples (n=2381) of fresh fecal materials were collected from northern pintail during November 2007-March 2008 at different locations of Tohoku district, main Island, Japan. We isolated 47 haemagglutinating viruses, out of which 25 were identified as AIVs, representing 9 combinations of 5 different haemagglutinin (HA) and 6 neuraminidase (NA) subtypes. Both H5 and H7 subtypes were identified and found to be low pathogenic. A further 11 viruses were grouped into APMV-1 (NDV). The rest of the viruses (n=11) remained to be identified. Some of the HA subtypes and NA subtypes detected during the first season reoccurred in the second season, as well as some of their combinations; yet, several new subtypes and combinations appeared during the second season. These findings indicate that different subtypes of AIVs, NDV and other haemagglutinating viruses circulate subclinically in the pintail populations sampled. Pintails should be regarded, potentially, as important spreaders of AIVs and NDVs, particularly due to their extensively ramified flyways, which include various inter-continental routes.

Pathological and microbiological studies of Japanese Hare (Lepus brachyurus angustidens) naturally infected with Francisella tularensis subsp. holarctica.

An adult male hare (Lepus brachyurus angustidens) was discovered in a moribund condition in the bush in the mountains of Aomori prefecture in Japan. Upon gross inspection, many ticks were found on the neck and the external ear regions, and more than half the ticks contained blood in the intestine. The skin around the tick bite wounds was alopecic and mildly thickened. At necropsy, enlargement of the cervical lymph nodes and spleen were observed. Histologically, acute necrotizing splenitis, lymphadenitis, hepatitis, pneumonia, myelitis, adrenalitis, and encephalitis with bacterial organisms were observed. The cutaneous lesions were chronic and cysts had formed in the areas marked by tick bites. Immunohistochemically, the organisms in the skin, liver, spleen, lymph nodes, lungs, adrenal glands, brain, bone marrow, and ticks were positive for F. tularensis antigen. Microbiological and polymerase chain reaction results were consistent with F. tularensis subsp. holarctica. Because the cutaneous lesions were more chronic than those in the visceral organs and F. tularensis was detected in the ticks, we inferred that F. tularensis was transmitted to the hare via tick bites.

Light and scanning electron microscopic study on the tongue and lingual papillae of the Japanese badgers, Meles meles anakuma.

We observed the three-dimensional structures of the external surface and connective tissue cores (CTCs), after exfoliation of the epithelium of the lingual papillae (filiform, fungiform and foliate papillae) of the Japanese badgers (Meles meles anakuma) using scanning electron microscopy and conventional light microscopy. Macroscopically, the tongue was elongated anterior-posteriorly and the apex rounded. Numerous filiform papillae and fungiform papillae were distributed all over the tongue except at the root. Seven vallate papillae were observed that had circumferential furrows and were arranged in V-shape. Numerous taste buds were observable in the furrows. Instead of foliate papillae, a lateral organ lacking taste buds was present on the lateral edge of the posterior tongue. Behind the vallate papillae, dome-like lingual tonsils that had globular tonsils were densely distributed in U-shaped arrangement. Rather long conical papillae were distributed around the vallate papillae. At the posterior end of the root of the tongue, lingual papillae were very much attenuated and only fold-like structure was seen. CTCs of filiform papillae had a main rod-like slender core and ovally arranged short accessory cores distributed around the main core. CTCs of fungiform papillae exhibited a columnar like appearance. The lingual papillae of Japanese badger's tongue fundamentally had morphological similarity with carnivore species, included the Pinnipedia.

Comparative morphology of the primate tongue.

To clarify the role of the primate tongue as a means to better understand the evolution of oral function among primates - an example of adaptation within the restricted phylogenetic group - we review the morphological knowledge of the tongues of extant primates in relation to phylogenetic classification. Prosimians tongues are more effective than those of Haplorhini for taking up food with the tongue alone, because they are capable of fine movement when outside the oral cavity. However, the role of the tongue in food uptake has diminished when juxtaposed with progress in hand manipulation of food and tools in Haplorhini, especially with the manipulation of tools by Homininae. This change in the tongue from prosimians to Homininae can be regarded as degeneration in food uptake by the tongue, although the functional role of the tongue within the oral cavity has not diminished. The distribution pattern and form of lingual papillae, except foliate papillae, are very similar among all reported primates species. Although foliate papillae are generally well developed in Haplorhini, most prosimian species have no foliate papillae, or a different type of papillae that substitute for foliate papillae. There are three vallate papillae in prosimian species and the New-World macaques, Platyrrhini. These papillae exhibit an inverted V-shape and are more numerous in Old World macaques, Catarrhini. These differences seem to be the result of phylogenetic origin.

Comparative morphology of the lingual papillae and their connective tissue cores in the tongue of the Abyssinian black-and-white colobus (Colobus guereza).

We observed the morphology of the lingual papillae (filiform, fungiform, foliate, and vallate) and their underlying connective tissue cores (CTCs) in Abyssinian black-and-white colobus monkeys using light and scanning electron microscopy. The tongues of both juvenile and senescent individuals were relatively short in the rostro-caudal direction, with a rounded apex. Lingual tori were absent. Numerous filiform papillae were distributed over the entire tongue, except at the lingual root. A pair of foliate papillae was present on both the lateral and caudal margins of the corpus. Three vallate papillae were distributed on the boundary between the caudal part of the body and the root in both juvenile and senescent individuals. Based on scanning electron microscopy observations, the morphologies of the filiform papillae differed between juvenile and senescent individuals. The epithelial surface of juvenile filiform papillae had a main process, but the associated processes were weak and the underlying CTCs displayed immature morphology. In contrast, the epithelial surface of senescent filiform papillae was associated with several accessory processes, and their underlying CTCs consisted of several auxiliary cores that nearly encircled the main core, forming a concavity in the papilla. CTCs of the filiform papillae showed variable morphology. Juvenile filiform CTCs exhibited a rather primitive morphology, resembling those of the hamster, mole, and Cape hyrax while, conversely, despite the basically folivorous diet of the Abyssinian black-and-white colobus, senescent filiform CTCs resembled those found in omnivorous primates, including members of the Callitrichinae and Homoidea, and also those in Carnivora (e.g., Canidae and Felidae).

Light and scanning electron microscopic study on the lingual papillae and their connective tissue cores of the Cape hyrax Procavia capensis.

We examined the epithelial surface and connective tissue cores (CTCs) of each lingual papilla on the Paenungulata, Cape hyrax (Procavia capensis), by scanning electron microscopy and light microscopy. The tongue consisted of a lingual apex, lingual body and lingual root. Filiform, fungiform and foliate papillae were observed on the dorsal surface of the tongue; however, fungiform papillae were quite diminished on the lingual prominence. Moreover, no clearly distinguishable vallate papillae were found on the tongue. Instead of vallate papillae, numerous dome-like large fungiform papillae were arranged in a row just in front of the rather large foliate papillae. Foliate papillae were situated in the one-third postero-lateral margin of the lingual body. The epithelium of filiform papillae was covered by a keratinized layer with kerato-hyaline granules, whereas weak keratinization was observed on the interpapillary epithelium. The external surface of the filiform papillae was conical in shape. CTCs of the filiform papillae were seen as a hood-like core with a semicircular concavity in the anterior portion of each core. Large filiform papillae were distributed on the lingual prominence. The CTCs of large filiform papillae after exfoliation of their epithelium consisted of a concave primary core and were associated with several small protrusions. The surface of fungiform papillae was smooth and dome-like. After removal of the epithelium, CTCs appeared as a flower bud-like primary core and were associated with several protrusions that were arranged on the rim of the primary core. Several taste buds were found on the top of the dorsal part of the epithelium of both fungiform and large fungiform papillae. Well-developed foliate papillae were seen and numerous taste buds could be observed in the lateral wall of the epithelium in a slit-like groove. The morphological characteristics of the tongue of the Cape hyrax had similarities with other Paenungulata such as Sirenia. However, three-dimensional characteristics, especially CTCs of lingual papillae, exhibited multiple similarities with rodents, insectivores and artiodactyls.

Morphology of the tongue in a newborn Stejneger's beaked whale (Mesoplodon stejnegeri).

This light and scanning electron microscopic (SEM) study on the tongue of a newborn Stejneger's beaked whale (Mesoplodon stejnegeri) demonstrated a clear difference in its form from than that of other cetacean and adult Stejneger's beaked whales. This newborn Stejneger's beaked whale had a spoon-like shaped tongue. The dorsal surface in the center part of the tongue was flat and did not have papillae, but there were marginal papillae and small papillae on the anterior part of the tongue. In the posterior of the tongue, hillock-shaped papillae with taste buds on the epithelium were observed.

Differential Distribution of Salmonella Serovars and Campylobacter spp. Isolates in Free-Living Crows and Broiler Chickens in Aomori, Japan.

Salmonella and Campylobacter cause foodborne enteritis mainly via the consumption of raw/undercooked contaminated poultry meat and products. Broiler flocks are primarily colonized with these bacteria; however, the underlying etiology remains unclear. The present study was conducted in order to obtain further information on the prevalence and genotypic distribution of Salmonella and Campylobacter in free-living crows and broiler flocks in a region for 2 years, thereby facilitating estimations of the potential risk of transmission of C. jejuni from crows to broiler flocks. Salmonella serovars Bredeney and Derby were isolated from 8 and 3 out of 123 captured crows, respectively, both of which are not common in broiler chickens. Campylobacter were isolated from all 89 crows tested and C. jejuni was prevalent (85 crows). Pulsed field gel electrophoresis showed broad diversity in the crow isolates of C. jejuni. However, 3 crow isolates and 2 broiler isolates showing similar banding patterns were assigned to different sequence types in multi-locus sequence typing. These results indicate that crows do not share Salmonella serovars with broilers, and harbor various genotypes of C. jejuni that differ from those of broiler flocks. Thus, our results indicate that crows are not a potential vector of these bacteria to broiler flocks in this region.

Scanning electron microscopic study on the tongue and lingual papillae of the adult Spotted seal, Phoca largha.

We observed the external surface and connective tissue cores (CTCs) of the lingual papillae (filiform, fungiform and vallate papillae) of adult Spotted seals (Phoca largha) using SEM and light microscopy. The tongue was V-shaped and its apex was rather rounded. On the dorsal surface from apex to the one-third posterior of the tongue, the lingual mucosa was densely covered by filiform papillae, with a scatted distribution of dome-like fungiform papillae, which have orthokeratinized epithelium. At the posterior part of the tongue, filiform papillae were totally diminished and their epithelium was parakeratinized. Approximately 6-7 vallate papillae were arranged in a V-shape on the posterior of the tongue. After removal of the epithelium, the CTCs of the filiform papillae that were distributed at apex consisted of a primary core and approximately 5-6 rod-shaped small accessory cores. The CTCs of filiform papillae that were distributed at anterior part of the tongue lacked primary protrusions and possessed approximately 10-15 rod shaped small accessory cores that were arranged in a horseshoe manner. The CTCs offungiform papillae had cylindrical primary cores and were fringed with accessory protrusion. In the Vallate papillae, taste buds were only seen at the dorsal epithelium.

Comparative morphological study on the stereo-structure of the lingual papillae and their connective tissue cores of the American beaver (Castor canadensis).

The lingual papillae and the connective tissue cores (CTC) of the American beaver were examined by light and scanning electron microscopy. The tongue of American beaver was about 9 cm in length, 3.5 cm in width, and has a lingual prominence. Four types of papillae (filiform, fungiform, vallate and foliate papillae) were observed. The filiform papillae can be classified into three types (filiform, large filiform and dorm-like papillae). Filiform papillae distributed on the anterior tongue and posterior of the lingual prominence consisted of a posterior thick main process and several small accessory processes. After removal of the epithelium, the CTCs of the filiform papillae had U-shaped, horseshoe-like primary cores with 10-15 rod-shaped small accessory cores. Large filiform papillae were distributed at the anterior margin of the lingual prominence. Dome-like papillae were distributed at the top of lingual prominence. Fungiform papillae were observed two types. Fungiform papillae, which were distributed at the anterior tongue, were round shaped. Fungiform papillae of the posterior of the lingual prominence were large and surrounded with a papillary groove. At the posterior of the tongue, three vallate papillae were arranged in a triangular pattern. Foliate papillae were on 22 to 25 parallel ridges and grooves.

Effects of environmental radiation on testes and spermatogenesis in wild large Japanese field mice (Apodemus speciosus) from Fukushima.

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident that occurred after the Great East Japan Earthquake in March 2011 released large quantities of radionuclides to the environment. The long-term effects of radioactive cesium (Cs) on biota are of particular concern. We investigated the accumulation of radioactive Cs derived from the FDNPP accident, and chronic effects of environmental radionuclides on male reproduction, in the large Japanese field mouse (Apodemus speciosus). In 2013 and 2014, wild mice were captured at 2 sites in Fukushima Prefecture and at 2 control sites that were distant from Fukushima. Although the median concentrations of (134)Cs and (137)Cs in the mice from Fukushima exceeded 4,000 Bq/kg, there were no significant differences in the apoptotic cell frequencies or the frequencies of morphologically abnormal sperm among the capture sites. Thus, we conclude that radiation did not cause substantial male subfertility in Fukushima during 2013 and 2014, and radionuclide pollution levels in the study sites would not be detrimental to spermatogenesis of the wild mice in Fukushima.

Survey of Francisella tularensis in Wild Animals in Japan in Areas Where Tularemia is Endemic.

Samples taken from 428 wild animals and 126 ticks, collected from a tularemia-endemic area in Japan between 2005 and 2013, were analyzed for the presence of Francisella tularensis. F. tularensis was isolated from a Japanese hare carcass whereas the samples from live animals and ticks were negative for F. tularensis by real-time PCR. Our results suggest that F. tularensis is still present in Japan although its prevalence is considerably low even in areas where tularemia is endemic.