Morphological analysis of corneal opacity in Shiba dog with GM1 gangliosidosis

GM1 gangliosidosis is one of the inherited metabolic lysosomal storage disorders characterized by neurological symptoms caused by beta-galactosidase deficiency and consequent accumulation of GM1 ganglioside in neuronal cells. Shiba dogs affected with GM1 gangliosidosis have been found to suffer from corneal opacity. In our morphological analysis, keratocyte enlargement was induced by abnormal intracellular accumulation of neutral carbohydrates, resulting in the loss of normal arrangement of collagen fibrils in the opaque cornea was found to be associated with the disorder. We therefore conclude that corneal opacity in this Shiba dog with GM1 gangliosidosis may be caused by neutral carbohydrate accumulation in lysosomes, swelling and dysfunction of keratocytes, and subsequent irregular arrangement of collagen fibrils in the corneal proper substance.     

Development of a culture protocol for Rhodomonas sp. Hf-1 strain through laboratory trials

Fisheries Science - Rhodomonas sp. Hf-1 is a marine microalgal strain with a high nutritional value. In order to produce this microalga effectively and inexpensively in a hatchery, its production...     

Interannual variation of the diet shifts and their effects on the fatness and growth of age‐0 Pacific bluefin tuna (Thunnus orientalis) off the southwestern Pacific coast of Japan

We investigated the effect of feeding habits on the fatness (length–weight relationship (LW)) and otolith growth of age‐0 Pacific bluefin tuna (PBF) (fork length (FL) of 15.0–29.9 cm) collected off the southwestern Pacific coast of Japan from July to August during 2010–2015. The feeding rate on Clupeiformes (FRc) was substantially influenced by the path of the Kuroshio Current during early summer. We suggest that the following patterns occurred in the feeding habits of PBF. In 2012 and 2014, the short distance from the coast to the Kuroshio provided high overlap between PBF and Clupeiformes and increased the opportunity for feeding, and this pattern likely caused the observed diet shift from Crustacea to Clupeiformes by smaller PBF in the studied years than those in other years. In 2011 and 2015, the encounter probability for Clupeiformes might have been low due to the long distance to the Kuroshio Current, which led PBF to actively consume non‐Clupeiformes Teleostei. In contrast, in August 2010 and 2015, PBF did not encounter Clupeiformes or other Teleostei and may have been forced to feed on a large number of Crustacea; this effect was likely due to high water temperatures. Despite the interannual fluctuation in the timing of the diet shift and the feeding intensity (FI), these factors did not contribute to growth in length; rather, they contributed to fatness. Considering size‐dependent mortality in the larval stage, these results suggest that only fast‐growing individuals survive, even if the feeding conditions drastically change.     

Age validation,growth and annual reproductive cycle of chub mackerel <Emphasis Type="Italic">Scomber japonicus</Emphasis> off the waters of northern Kyushu and in the East China Sea

The age and growth of chub mackerel Scomber japonicus collected from the East China Sea and the northern waters off Kyushu between June 2000 and June 2001 were determined by observing the otolith surface after dipping it in xylene. The translucent and opaque zones on the otolith surface were identified, and the number of translucent zones was counted. Monthly changes in the frequency of fish with translucent zones on the otolith margin, and in the marginal increments, indicated that the translucent zones were formed between April and June. The seasonal pattern of annulus formation on the otolith became clear by observing the otoliths of fish with known ages, and the otolith formation in wild fish was consistent with that of fish with known ages. The mean gonadosomatic index of male and female fish was high from March to May, and spawning females were observed from mid-March to mid-May. The estimated ages were 1–5 years for males and 1–6 years for females. The von Bertalanffy growth parameters did not significantly differ between male and female. The model was obtained as FL _t=406×{1−exp[−0.372×(t+1.68)]     

Age, growth, and reproductive characteristics of dolphinfish Coryphaena hippurus in the waters off west Kyushu, northern East China Sea

The growth and reproductive characteristics of dolphinfish Coryphaena hippurus collected in the waters off western Kyushu from May 2008 to April 2011 were determined based on scale and otolith readings and gonad histological examinations, respectively. Based on annual increments in scales and daily increments in sagittal otoliths, the von Bertalanffy growth curves in male and females were determined as $ FL_{t} = 1049[1 - \exp \{ - 0.835(t + 6.975 \times 10^{ - 14} )\} ] $ and $ FL_{t} = 938[1 - \exp \{ - 1.029(t + 6.975 \times 10^{ - 14} )\} ] $ , respectively, where FL _t is the mean fork length (mm) at age t. The spawning period was found to last from June to August for dolphinfish, based on an examination of the monthly changes in the gonadosomatic index and histological observations. Therefore, based on the relationship between the fork length and the developmental stage of the testes or ovaries, male and female dolphinfish were found to reach sexual maturity by the following spawning season after hatching in the northern East China Sea.     

Expression and localization of estrogen receptors α and β mRNA in medullary bone of laying hens

The aim of this study was to observe the expression and localization of estrogen receptor (ER) α and ER β mRNA in the medullary bone of laying hens. First, medullary bone, liver, kidney, and shell gland of the oviduct tissues were dissected from laying hens. Then, the total cellular RNA was isolated from each tissue specimen, and the ER α and ER β mRNA expression was observed using semiquantitative RT‐PCR. Second, the localization of ER α mRNA in the medullary bone was detected with in situ hybridization using digoxigenin‐11‐UTP‐labeled cRNA probes. As a result, the expression of ER α mRNA was higher than that of ER β mRNA in the medullary bone, liver, and shell gland of the oviduct from laying hens. In the kidney, ER α mRNA expression was lower than that of ER β mRNA. The expression pattern of ER α and ER β mRNA of the medullary bone was similar to that of the shell gland of the oviduct. Moreover, ER α mRNA was intensively expressed in osteoblasts on the medullary bone surface and bone marrow stromal cells but was not expressed in osteoclasts. These results suggest that in medullary bone, estrogen action may be regulated not by ER β but by ER α.     

GM2-gangliosidosis variant 0 (Sandhoff-like disease) in a family of Japanese domestic cats

A five-month-old, female Japanese domestic shorthair cat with proportionate dwarfism developed neurological disorders, including ataxia, decreased postural responses and generalised body and head tremors, at between two and five months of age. Leucocytosis due to lymphocytosis with abnormal cytoplasmic vacuolations was observed. The concentration of G(M2)-ganglioside in its cerebrospinal fluid was markedly higher than in normal cats, and the activities of beta-hexosaminidases A and B in its leucocytes were markedly reduced. On the basis of these biochemical data, the cat was diagnosed antemortem with G(M2)-gangliosidosis variant 0 (Sandhoff-like disease). The neurological signs became more severe and the cat died at 10 months of age. Histopathologically, neurons throughout the central nervous system were distended, and an ultrastructural study revealed membranous cytoplasmic bodies in these distended neurons. The compound which accumulated in the brain was identified as G(M2)-ganglioside, confirming G(M2)-gangliosidosis. A family study revealed that there were probable heterozygous carriers in which the activities of leucocyte beta-hexosaminidases A and B were less than half the normal value. The Sandhoff-like disease observed in this family of Japanese domestic cats is the first occurrence reported in Japan.     

Magnetic resonance imaging of neuronal ceroid lipofuscinosis in a border collie

A castrated male border collie 23 months of age weighing 19.4 kg was referred to the Animal Medical Center of Nihon University with complaints of visual disturbance and behavioral abnormality, hyperacusis and morbid fear. The MRI examination revealed the slight dilated cerebral sulci and cerebellar fissures and left ventricular enlargement. This is the first report of MRI findings of canine neuronal ceroid lipofuscinosis.