Biology and status of aquaculture for giant clams (Tridacnidae) in the Ryukyu Islands, southern Japan

The Ryukyu Islands consist of many islands located between Kyushu in mainland Japan and Taiwan. The islands in the south-western area of the Ryukyu Islands belong to the Okinawa Prefecture. The Ryukyu Islands are strongly affected by the Kuroshio Current and are renowned for their coral reefs with high diversity of tropical and subtropical species. Giant clams traditionally have been utilized as fisheries resources for a long time in this area. According to fisheries statistics, catches of Tridacna crocea in Okinawa have decreased drastically during the last 30 years and currently are less than one tenth of previous catches. Fishing can easily deplete stocks of giant clams because the clams inhabit shallow waters and take at least three years to attain sexual maturity. Techniques for the mass seed production and aquaculture of three species (T. crocea, T. squamosa, and T. derasa) were established in Okinawa. Four hundred thousand seeds of giant clams of 8 mm shell length (SL) are supplied to fishermen for use in aquaculture or stock enhancement every year. This paper will review the (1) biology of giant clams, (2) present status of aquaculture of giant clams in Okinawa, and (3) other studies on giant clams in southern Japan

Absence of in vivo mutagenicity of multi-walled carbon nanotubes in single intratracheal instillation study using F344 gpt delta rats

Abstract Introduction It is known that fibrous particles of micrometer length, such as carbon nanotubes, which have same dimensions as asbestos, are carcinogenic. Carcinogenicity of nanomaterials is strongly related to inflammatory reactions; however, the genotoxicity mechanism(s) is unclear. Indeed, inconsistent results on genotoxicity of multi-walled carbon nanotubes (MWCNTs) have been shown in several reports. Therefore, we analyzed the in vivo genotoxicity induced by an intratracheal instillation of straight MWCNTs in rats using a different test system\u2014the Pig-a gene mutation assay\u2014that can reflect the genotoxicity occurring in the bone marrow. Since lungs were directly exposed to MWCNTs upon intratracheal instillation, we also performed the gpt assay using the lungs. Findings We detected no significant differences in Pig-a mutant frequencies (MFs) between the MWCNT-treated and control rats. Additionally, we detected no significant differences in gpt MFs in the lung between the MWCNT-treated and control rats. Conclusions Our findings indicated that a single intratracheal instillation of MWCNTs was non-mutagenic to both the bone marrow and lung of rats

A 90-day Feeding Toxicity Study of l-Serine in Male and Female Fischer 344 Rats

A subchronic feeding study of l-serine (l-Ser) was conducted with groups of 10 male and 10 female Fischer 344 rats fed a powder diet containing 0, 0.06, 0.5, 1.5 or 5.0% concentrations of l-Ser for 90 days. There were no toxicologically significant, treatment-related changes with regards to body weight, food intake, water intake or urinalysis data. In several of the hematology, serum biochemistry and organ weight parameters, significant changes were observed between some of the treated groups and the controls. All these changes, however, were subtle and lacked any corresponding pathological findings. In addition, the increased or decreased values remained within the range of the historical control values. In fact, histopathological assessment revealed only sporadic and/or spontaneous lesions. In conclusion, the no-observed-adverse-effect-level (NOAEL) for l-Ser was, therefore, determined to be at least a dietary dose of 5.0% (2765.0 mg/kg body weight/day for males and 2905.1 mg/kg body weight/day for females) under the present experimental conditions

The outcomes of reconstruction using frozen autograft combined with iodine-coated implants for malignant bone tumors: Compared with non-coated implants

Objective: We perform reconstruction using frozen tumor bone treated by liquid nitrogen after excision of malignant bone tumors. To prevent post-operative infection, we use iodine-coated implants that we developed. The purpose of this study is to compare the outcome of reconstruction using frozen autograft with non-coated implants (group N) and iodine-coated implants (group I).Methods: Sixty-two patients were included in group N. The mean age was 31.9 ± 2.3 years. A total of 20 patients died and two were lost to follow-up, averaging 20.0 ± 2.9 months post-operatively, leaving 40 patients available for an assessment at a mean of 79.1 ± 5.8 months post-operatively. There were 38 patients in group I. The mean age was 29.8 ± 3.9 years. The mean follow-up period was 32.1 ± 3.0 months. All patients were alive at the latest follow-up. Survival of frozen bone was determined by Kaplan-Meier analysis.Results: In group N, survival of frozen bone was 80.7 ± 6.0% and 57.4 ± 10.2% at 5 and 10 years, respectively. Complications were encountered in 31 of 62 patients (50.0%), including deep infection in 10 (16.1%), fracture in 11 (17.7%), local soft-tissue recurrence in 6 (9.7%) and bone absorption in 4 (6.5%). In group I, survival of frozen bone was 86.7 ± 6.3% at 5 years. Complications were encountered in 8 of 38 patients (21.1%), including deep infection in one (2.6%), fracture in four (10.5%), local soft-tissue recurrence in two (5.3%) and bone absorption in one (2.6%). There was a significantly lower infection rate in group I (P = 0.032).Conclusion: Reconstruction using frozen autograft combined with iodine-coated implants for patients with malignant bone tumor is very useful method in which good limb function can be gained with minimized risk of infection. © The Author 2016. Published by Oxford University Press. All rights reserved.Article number hyw065 / Embargo Period 6 month

The Met268Pro Mutation of Mouse TRPA1 Changes the Effect of Caffeine from Activation to Suppression

The transient receptor potential A1 channel (TRPA1) is activated by various compounds, including isothiocyanates, menthol, and cinnamaldehyde. The sensitivities of the rodent and human isoforms of TRPA1 to menthol and the cysteine-attacking compound CMP1 differ, and the molecular determinants for these differences have been identified in the 5th transmembrane region (TM5) for menthol and TM6 for CMP1. We recently reported that caffeine activates mouse TRPA1 (mTRPA1) but suppresses human TRPA1 (hTRPA1). Here we aimed to identify the molecular determinant that is responsible for species-specific differences in the response to caffeine by analyzing the functional properties of various chimeras expressed in Xenopus oocytes. We initially found that the region between amino acids 231 and 287, in the distal N-terminal cytoplasmic region of mTRPA1, is critical. In a mutagenesis study of this region, we subsequently observed that introduction of a Met268Pro point mutation into mTRPA1 changed the effect of caffeine from activation to suppression. Because the region including Met-268 is different from other reported ligand-binding sites and from the EF-hand motif, these results suggest that the caffeine response is mediated by a unique mechanism, and confirm the importance of the distal N-terminal region for regulation of TRPA1 channel activity