Ecology,physiology and genetics of a phycodnavirus infecting the noxious bloom-forming raphidophyte <Emphasis Type="Italic">Heterosigma akashiwo</Emphasis>

Abstract:   Heterosigma akashiwo virus (HaV) is a large icosahedral virus (∼0.2 μm) harboring a double-stranded DNA (dsDNA) genome (∼294 kbp). The virus is the only member of the genus Raphidovirus in the family Phycodnaviridae. Since its first discovery, a number of ecologic, physiologic and genetic studies about HaV have been conducted; especially, the relationship between H. akashiwo and HaV in nature was studied and viral infection is now regarded as a significant factor influencing the dynamics and termination of H. akashiwo blooms. HaV infection has considerable impacts on H. akashiwo populations in both aspects of fluctuation in biomass (quantity) and changes in clonal composition (quality). Partial sequencing of the HaV genome revealed that a number of genes showed considerable similarity to those of other protist-infecting viruses; still, the phylogenetic position of HaV suggested a number of enigmas in host–virus coevolution. Here are summarized the ecology, physiology and genetics of HaV especially from the viewpoint of the host–virus relationship.     

Chemical structures of the condensed tannins in the fruits of Diospyros species

The structural variety of the condensed tannins (proanthocyanidins) in the fruits of 16Diospyros species are reported. Eleven species contained condensed tannins mostly consisting of a mixture of catechin (CA) and gallocatechin (GCA) repeating units; the other five species did not. The GCA content in the CA-GCA total varied from 0.3% to 84.6%. The number of esterified gallic acid per one flavan repeating unit (degree of galloylation, DG) ranged from 0.01 to 0.89. The GCA content was found to be proportional to the DG values. Thus, 16Diospyros species tested may be classified into five groups by the analytical data of their condensed tannins. It may be interesting to compare their structural characteristics with those of the condensed tannins in other fruits, leaves, woods, and barks from the viewpoint of their biosynthesis and function in the plants.Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1995     

Responses to the Standard for Exchange of Nonclinical Data (SEND) in non-US countries

The Standard for the Exchange of Nonclinical Data (SEND), adopted by the US FDA, is part of a set of regulations and guidances requiring the submission of standardized electronic study data for nonclinical and clinical data submissions. SEND is the nonclinical implementation of SDTM (Study Data Tabulation Model), the standard electronic format for clinical regulatory submissions to FDA. SEND, SDTM, and the associated Controlled Terminology have been developed by CDISC (Clinical Data Interchange Standards Consortium). In order to successfully implement SEND, interdisciplinary contributions between sponsors and CROs, need a model for task allocation. This is being undertaken by the Pharmaceutical Users Software Exchange (PhUSE). Because SEND is currently the preferred submission format of the US FDA only and will become required by it starting in December 2016, only American academic societies and companies are actively involved. An exception to this is the INHAND initiative, which leads the way in standardizing terminology for toxicological pathology. On the other hand, international globalization of other clinical and nonclinical practices is not feasible because there are substantial differences between the US and non-US countries in CRO involvement in drug development. Thus, non-US countries must consider and develop approaches to SEND that meet their needs. This paper summarizes the activities of the major organizations involved in SEND development and implementation, discusses the effective use of SEND, and details a compliance scheme (research material of the Showa University School of Medicine) illustrating how pharmaceutical companies can complete a large amount of work up to an FDA application with the effective utilization of CROs and solution providers.     

Nitrogen-fixing activity in decomposing litter of three tree species at a watershed in eastern Japan

Nitrogen fixation during litter decomposition was studied for 34 months using litterbags containing newly fallen litter of coniferous species Cryptomeria japonica and Pinus densiflora and that of deciduous species Quercus serrata. Litterbags were set in contact with the forest floor in a deciduous broad-leaved forest near the top of a slope and in a C. japonica stand at the middle of the slope at a watershed in eastern Japan. Nitrogen-fixing activity, estimated by acetylene reduction after 16 and 19 months of incubation, was 62.65–3.86 nmoles C₂H₄ h⁻¹ g⁻¹ DW in Cryptomeria litter, but only 1.07–0.09 in Pinus and 0.72–0.04 in Quercus. The rate of N increase in decomposing litter was highest in Cryptomeria. Fungal biomass in decomposing litter, estimated by ergosterol content, increased during the initial 16 months of incubation in Cryptomeria and Quercus, and during the initial 19 months of incubation in Pinus. The litter decomposition rate was highest in Cryptomeria among the three species, due to increased N content and fungal biomass in Cryptomeria litter. Thus, N increase in decomposing Cryptomeria litter affects the subsequent N dynamics and decomposition pattern.     

Cathepsin K-dependent toll-like receptor 9 signaling revealed in experimental arthritis

Cathepsin K was originally identified as an osteoclast-specific lysosomal protease, the inhibitor of which has been considered might have therapeutic potential. We show that inhibition of cathepsin K could potently suppress autoimmune inflammation of the joints as well as osteoclastic bone resorption in autoimmune arthritis. Furthermore, cathepsin K-/- mice were resistant to experimental autoimmune encephalomyelitis. Pharmacological inhibition or targeted disruption of cathepsin K resulted in defective Toll-like receptor 9 signaling in dendritic cells in response to unmethylated CpG DNA, which in turn led to attenuated induction of T helper 17 cells, without affecting the antigen-presenting ability of dendritic cells. These results suggest that cathepsin K plays an important role in the immune system and may serve as a valid therapeutic target in autoimmune diseases.     

Prevalence of Borna disease virus antibodies in healthy Japanese black cattle in Kyushu

Epidemiological studies have demonstrated that asymptomatic infection of Borna disease virus (BDV) is found in various species of animals in Japan. Recent reports have also revealed that neurological diseases caused by this virus could exist in horses, cattle, a dog, and cats in this country. In this study, we investigated seroprevalence of BDV antibodies in Japanese black cows reared in Kyushu, the southernmost main island of Japan, using ELISA and Western-immunoblotting. Of 101 serum samples, 11 (10.9%) and 21(20.7%) sera were identified as having antibodies to the BDV N and P antigens, respectively. Among the positive sera, three cows (2.9%) were seropositive for both of the antigens. Furthermore, interestingly, only female cows showed antibodies to P, whereas N antibodies were detected in male and female cows with a comparative ratio. Together with previous studies, our results indicate that BDV might be widely spread in cattle raised in Japan. Furthermore, this is the first report to show that beef cattle, Japanese black cattle, have antibodies against a possible zoonotic pathogen, BDV.     

Correlation between villous height and the disaccharidase activity in the small intestine of piglets from nursing to growing

Early weaning induces villous atrophy in the small intestine. Reduction in villous height in the small intestine after weaning is associated with reductions in brush‐border enzyme activity. Body weight gain after weaning is, therefore, correlated with villous height. This evidence suggested that the maintenance of small intestinal structure and function after weaning is important for the growth of young pigs. On the other hand, the relationship between villous height and the activity of the digestive enzymes in the small intestine has not been studied with piglets from the suckling to the growing period. Five suckling piglets, four piglets in the proximal stage of weaning, four pigs in the distal stage of weaning and four growing pigs were used. The activities of lactase (LA), sucrase (SA) and maltase (MA) were determined. LA showed a positive correlation with villous height in weaning. SA and MA were positively correlated with villous height from suckling to growing. In a previous study, non‐infectious dyspeptic diarrhea was frequently observed in growing piglets on Japanese swine farms. The maintenance of villous height to retain disaccharidase activity may prevent dyspepsic diarrhea in this stage.     

Relationship of European persimmon (Diospyros kaki Thunb.) cultivars to Asian cultivars, characterized using AFLPs

Sixty one persimmon (Diospyros kaki Thunb.) selections, including 17 Italian, 11 Spanish, 13 Japanese, six Korean, five Chinese, one Israeli, and eight of unknown origin, were evaluated for genetic differences by AFLP analysis. Relationships among cultivars were evaluated by UPGMA clustering, Neighbor Joining, and MultiDimensional Scaling. While similarities among groups were generally less than 0.60, both UPGMA and Neighbor Joining separated European and Asian cultivars. Spanish and Italian cultivars were not separated by any of the analyses, suggesting that they share a common gene pool, while Japanese, Chinese and Korean cultivars formed distinct clusters. Diversity within groups was greater than diversity between groups. Most cultivars were quite polymorphic (only 0.60–0.80 similarity between cultivars). In addition, the presence of several Japanese cultivars in the European group and a group of European cultivars nested between Chinese and Korean groups suggest that similar, but different progenitors were used in the development of the present European cultivars. ‘Kaki Tipo’ selections from different sources were clearly different by AFLP analysis, indicating that they are separate cultivars.     

Effect of dietary fish oil intake on ubiquitin ligase expression during muscle atrophy induced by sciatic nerve denervation in mice

Dietary fish oil intake improves muscle atrophy in several atrophy models however the effect on denervation‐induced muscle atrophy is not clear. Thus, the aim of this study was to investigate the effects of dietary fish oil intake on muscle atrophy and the expression of muscle atrophy markers induced by sciatic nerve denervation in mice. We performed histological and quantitative mRNA expression analysis of muscle atrophy markers in mice fed with fish oil with sciatic nerve denervation. Histological analysis indicated that dietary fish oil intake slightly prevented the decrease of muscle fiber diameter induced by denervation treatment. In addition, dietary fish oil intake suppressed the MuRF1 (tripartite motif‐containing 63) expression up‐regulated by denervation treatment, and this was due to decreased tumor necrosis factor‐alpha (TNF‐α) production in skeletal muscle. We concluded that dietary fish oil intake suppressed MuRF1 expression by decreasing TNF‐α production during muscle atrophy induced by sciatic nerve denervation in mice.     

Improved porcine model for Shiga toxin‐producing Escherichia coli infection by deprivation of colostrum feeding in newborn piglets

Porcine edema disease (ED) is a toxemia caused by enteric infection with Shiga toxin 2e (Stx2e)‐producing Escherichia coli (STEC). ED occurs most frequently during the weaning period and is manifested as emaciation associated with high mortality. In our experimental infection with a specific STEC strain, we failed to cause the suppression of weight gain in piglets, which is a typical symptom of ED, in two consecutive experiments. Therefore, we examined the effects of deprivation of colostrum on the sensitivity of newborn piglets to STEC infection. Neonatal pigs were categorized into two groups: one fed artificial milk instead of colostrum in the first 24 h after birth and then returned to the care of their mother, the other breastfed by a surrogate mother until weaning. The oral challenge with 10¹¹ colony‐forming units of virulent STEC strain on days 25, 26 and 27 caused suppression of weight gain and other ED symptoms in both groups, suggesting that colostrum deprivation from piglets was effective in enhancing susceptibility to STEC. Two successive STEC infection experiments using colostrum‐deprived piglets reproduced this result, leading us to conclude that this improved ED piglet model is more sensitive to STEC infection than the previously established models.