Sphaerularia vespae sp. nov. (Nematoda, Tylenchomorpha, Sphaerularioidea), an endoparasite of a common Japanese hornet, Vespa simillima Smith (Insecta, Hymenoptera, Vespidae)

Sphaerularia vespae sp. nov., an endoparasite of a common Japanese hornet, Vespa simillima is described from Hokkaido, Japan, and its molecular sequence profiles are given. This newly discovered nematode appears to belong to the genus Sphaerularia, judging from its characteristic parasitic form, the uterium, which looks like a sausage with many verrucae on its surface. Sphaerularia vespae sp. nov. is distinguished from S. bombi, the only other nominal species of the genus, by the morphology of the male bursa, female tail, and anterior end of parasitic juveniles. SSU, ITS, and D2D3 (LSU) DNA sequences were determined for S. vespae sp. nov. and compared with those from related nematodes obtained from the GenBank database. The sequences from S. vespae sp. nov. were close to those of S. bombi and several another tylenchid entomoparasitic nematodes. Sphaerularia vespae sp. nov. parasitizes overwintering gynes of the hornet and practically sterilizes them, as S. bombi does for bumblebee gynes.     

Sorbitol dehydrogenase overexpression potentiates glucose toxicity to cultured retinal pericytes

The polyol pathway consists of two enzymes, aldose reductase (AR) and sorbitol dehydrogenase (SDH). There is a growing body of evidence to suggest that acceleration of the polyol pathway is implicated in the pathogenesis of diabetic vascular complications. However, a functional role remains to be elucidated for SDH in the development and progression of diabetic retinopathy. In this study, cultured bovine retinal capillary pericytes were used to investigate the effects of SDH overexpression on glucose toxicity. High glucose modestly increased reactive oxygen species (ROS) generation, decreased DNA synthesis, and up-regulated vascular endothelial growth factor (VEGF) mRNA levels in cultured pericytes. SDH overexpression was found to significantly stimulate ROS generation in high glucose-exposed pericytes and subsequently potentiate the cytopathic effects of glucose. Fidarestat, a newly developed AR inhibitor, and N-acetylcysteine, an antioxidant, completely prevented these deleterious effects of SDH overexpression on pericytes. Furthermore, fidarestat administration was found to significantly prevent vascular hyperpermeability, the characteristic changes of the early phase of diabetic retinopathy, in streptozotocin-induced diabetic rats. Our present results suggest that SDH-mediated conversion of sorbitol to fructose and the resultant ROS generation may play an active role in the pathogenesis of diabetic retinopathy. Blockage of sorbitol formation by fidarestat could be a promising therapeutic strategy for the treatment of early phase of diabetic retinopathy.     

Fishery management in Japan

There are few legal marine protected areas in Japan rather than fishing-ban areas. Fishers did not seek legal fishing-ban areas but they did establish fishing-ban areas by autonomous bases. We briefly introduce the institutional history and features of Japanese coastal fishery management, including the past decade’s major legislative developments. Japan still has a decentralized co-management system involving fishers and the government, and ca. 98% of Japanese fishers are artisanal. There are several successful cases of coastal fisheries management in Japan. However, offshore industrial fisheries have problems in Japan. We compare coastal fisheries co-management between Japan and Chile. We finally discuss the possibility of improvement for Japanese fisheries.     

Neuronal differentiation of PC12 cells as a result of prevention of cell death by bcl-2

Rat pheochromocytoma PC12 cells die when cultured in serum-free medium. Neurotrophic factors can rescue PC12 cells from cell death, and induce neuronal differentiation. To further investigation the relationship among cell death, survival, and differentiation, the bcl-2 cDNA, which is known to prevent apoptosis in various types of cells, was transfected into PC12 cells. Six monoclonal bcl-2-transfected cell lines were isolated and confirmed to express mRNA and protein product of bcl-2. The wild-type and bcl-2-transfected PC12 cells were kept to adhere to collagen-coated dishes at the inintiation of serum-free experiments to avoid cellular damage due to detachment of the cells by triturtion. Even under the conditions, the control PC12 cells mostly died within 24 h, when cultured in serum-free medium whereas those expressing Bcl-2 survived even for 7 days in serum-free medium. Moreover, outgrowth of long processes in thebcl-2-transfected cells was only observed under the condition to keep the cells attached to the dishes in serum-free medium without any additive neurotrophic or growth factors. Neurofilament medium protein, which is a neuron-specific cytoskeletal component, was also expressed in the differentited cells, suggesting that the long processes in bcl-2-transfected PC12 cells are neurites. However, neuronal differentiation of PC12 cells expressing Bcl-2 was not observed when cultured in serum-containing medium. Accordingly, survival of PC12 cells expressing Bcl-2 under the condition which cells usually die may be accompanied with neuronal differentiation. 1994 John Wiley & Sons, Inc.     

Cloning and Characterization of Rat Cellular Nucleic Acid Binding Protein (CNBP) cDNA

We cloned and sequenced the cDNAs which code for rat cellularnucleic acid binding protein (CNBP). In-frame insertion/deletiondifferences were found among the clones at two sites in theopen reading frame, suggesting alternative splicing of the messageor the presence of multiple genes which code for this protein.The deduced amino acid sequence revealed that one rat CNBP sequencewas completely identical to its human counterpart. This strikingconservation, together with the fact that homologous genes havebeen found in various organisms including Schizosaccharomycespombe, suggests that CNBP plays a basic biological role in eukaryoticcells. The recombinant GST-CNBP fusion protein produced in Escherichiacoli bound to a G-rich single-stranded RNA and DNA in a sequence-specificmanner.     

Complete genome sequence of enterohemorrhagic Escherichia coli O157:H7 and genomic comparison with a laboratory strain K-12.

Escherichia coli O157:H7 is a major food-borne infectious pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Here we report the complete chromosome sequence of an O157:H7 strain isolated from the Sakai outbreak, and the results of genomic comparison with a benign laboratory strain, K-12 MG1655. The chromosome is 5.5 Mb in size, 859 Kb larger than that of K-12. We identified a 4.1-Mb sequence highly conserved between the two strains, which may represent the fundamental backbone of the E. coli chromosome. The remaining 1.4-Mb sequence comprises of O157:H7-specific sequences, most of which are horizontally transferred foreign DNAs. The predominant roles of bacteriophages in the emergence of O157:H7 is evident by the presence of 24 prophages and prophage-like elements that occupy more than half of the O157:H7-specific sequences. The O157:H7 chromosome encodes 1632 proteins and 20 tRNAs that are not present in K-12. Among these, at least 131 proteins are assumed to have virulence-related functions. Genome-wide codon usage analysis suggested that the O157:H7-specific tRNAs are involved in the efficient expression of the strain-specific genes. A complete set of the genes specific to O157:H7 presented here sheds new insight into the pathogenicity and the physiology of O157:H7, and will open a way to fully understand the molecular mechanisms underlying the O157:H7 infection.     

Corticotropin-releasing hormone and pituitary-adrenocortical responses in chronically stressed rats

Brain corticotropin-releasing hormone (CRH) concentration and pituitary adreno-cortical responses were examined in chronically stressed rats: body restraint stress (6 h/day) for 4 or 5 weeks. Stressed rats showed a reduction in weight gain. CRH concentration in the median eminence and the rest of the hypothalamus were not different between control and chronically immobilized rats. The anterior pituitary adenocorticotropic hormone (ACTH) concentration was elevated in chronically stressed rats, whereas plasma ACTH and corticosterone levels did not differ from the control values. The median eminence CRH concentration was reduced to the same extent at 5 min after onset of ether exposure (1 min) in chronically immobilized rats and controls. However, plasma ACTH and corticosterone showed greater responses to ether stress in chronically immobilized rats than in control rats. Plasma ACTH and corticosterone responses to exogenous CRH were not different between control and chronically immobilized rats, while the response to arginine vasopressin (AVP) was significantly greater in chronically immobilized rats. These results suggest that chronic stress caused an increase in the ACTH-secreting mechanism and that pituitary hypersensitivity to vasopressin might at least be partly responsible for this.