Anatomy and Histology of the Eye of the Nutria : Evidence of Adaptation to a Semi-aquatic Life.

The nutria is a large, semi-aquatic rodent that, being invasive, is having a growing impact on the ecosystem in western Japan. Knowledge regarding physical adaptations to the nutria's lifestyle and habitual activities would be useful for effectively controlling and preventing their spread. Nutrias spend time on land and in water, feeding on agricultural crops and wild grasses growing near the waterside, as well as aquatic plants and shellfish.

Microbial community analysis in the gills of abalones suggested possible dominance of epsilonproteobacterium in .

Gills are important organs for aquatic invertebrates because they harbor chemosynthetic bacteria, which fix inorganic carbon and/or nitrogen and provide their hosts with organic compounds. Nevertheless, in contrast to the intensive researches related to the gut microbiota, much is still needed to further understand the microbiota within the gills of invertebrates. Using abalones as a model, we investigated the community structure of microbes associated with the gills of these invertebrates using next-generation sequencing.

A lambda-shaped retractor lentis muscle in the yellowfin goby Acanthogobius flavimanus.

We identified a morphologically uncommon piscine retractor lentis muscle in the yellowfin goby Acanthogobius flavimanus. This lentis muscle has a shape similar to the Greek small letter lambda (λ). The two legs of the muscle are attached to the retinal periphery at the ventral eyecup, while the tip is connected to the lens surface by a ligament.

Visual pigment genes and absorbance spectra in the Japanese sardine Sardinops melanostictus (Teleostei: Clupeiformes).

The spectral absorbance of photoreceptor visual pigments and the opsin gene class of the visual pigments was investigated in Sardinops melanostictus. Microspectrophotometric (MSP) measurements showed that the rod photoreceptors had peak absorbance spectra (λ) at 502 nm. The spectral sensitivity of single cones was centered at 393 nm.

Morphological characteristics of eyes and retinas of two sardines (Sardinops melanostictus and Etrumeus sadina, Clupeidae) and an anchovy (Engraulis japonicus, Engraulididae).

The morphology of the eyes and distribution of retinal ganglion cells in two sardine species (Sardinops melanostictus and Etrumeus sadina, Clupeidae) and the Japanese anchovy (Engraulis japonicus, Engraulididae) were investigated anatomically and histologically. The eyes of the sardines faced a slightly dorsolateral direction with the visual field extended obliquely upward. In contrast, the eyes in the anchovy were almost laterally directed.

Retinal ganglion cell topography in juvenile Pacific bluefin tuna Thunnus orientalis (Temminck and Schlegel).

The retinal ganglion cell distribution, which is known to reflect fish feeding behavior, was investigated in juvenile Pacific bluefin tuna Thunnus orientalis. During the course of examination, regularly arrayed cells with a distinctive larger soma, which may be regarded as motion-sensitive cells, were found. The topographical distribution of ordinary-sized ganglion cells, which is usually utilized to estimate fish visual axis and/or visual field characteristics, showed that the highest-density area, termed the area centralis, was localized in the ventral-temporal retina.

Three cone opsin genes determine the properties of the visual spectra in the Japanese anchovy, Engraulis japonicus (Engraulidae, Teleostei).

A complement of cone visual pigments was identified in the Japanese anchovy Engraulis japonicus, one of the engraulid fish species that has a retina specialized for polarization and color vision. The nature of the chromophore bound to opsin proteins was investigated using high performance liquid chromatography. The opsin genes were then cloned and sequenced, and the absorption spectra of different types of cones were obtained by microspectrophotometry.

Identification of mouse mutant cells exhibiting plastic mutant phenotype II; ionizing radiation-induced mutant phenotype plasticity is not dependent on DNA methylation of the hypoxanthine phosphoribosyl transferase gene in mouse FM3A cells.

As we previously reported, we isolated and examined mouse mutant cells exhibiting phenotypic plasticity. Approximately 10% of 6-thioguanine resistant (6TG(R)) cells derived from the irradiated cell population exhibited phenotypic plasticity and reverted to wild type HAT resistance (HAT(R)). Similar mutant cells were also identified in an un-irradiated wild type cell population, but at a lower frequency.

Relationship between catheter care and catheter-associated urinary tract infection at Japanese general hospitals: a prospective observational study.

Background: The risk factors for catheter-associated urinary tract infections (CAUTIs) that are associated with catheter care have not been examined in detail by prospective studies or randomised clinical trials.

Objectives: To examine the patterns of catheter care and to identify the CAUTI risk factors associated with catheter care.

Design: Prospective observational study.

Computational determination of refractive index distribution in the crystalline cones of the compound eye of Antarctic krill (Euphausia superba).

In order to understand how a compound eye channels light to the retina and forms an image, one needs to know the refractive index distribution in the crystalline cones. Direct measurements of the refractive indices require sections of fresh, unfixed tissue and the use of an interference microscope, but frequently neither is available. Using the eye of the Antarctic krill Euphausia superba (the main food of baleen whales) we developed a computational method to predict a likely refractive index distribution non-invasively from sections of fixed material without the need of an interference microscope.

Retinal topography of ganglion cells and putative UV-sensitive cones in two Antarctic fishes: Pagothenia borchgrevinki and Trematomus bernacchii (Nototheniidae).

Accessory corner cones (ACC) have recently been suggested to be UV-sensitive photoreceptor cells. With a view toward explaining prey detection, we examined the topography of retinal ganglion cells and ACCs in two Antarctic nototheniids occupying different ecological niches: the cryopelagic Pagothenia borchgrevinki and the benthic Trematomus bernacchii. Isodensity maps of retinal ganglion cells showed that the main visual axis, coincident with the feeding vector, was in a forward direction in both species.