Simultaneous maturation of two discrete oocyte batches in ayu

Ayu Plecoglossus altivelis including amphidromous and landlocked populations, are known for batch spawning. Unusual clutches at ovulation were observed from rearing stocks that were naturally induced to sexual maturation. Two peaks occurred simultaneously in the frequency distribution of egg size, compared to normal fish, which have clutches with unimodal size distribution. The eggs in the small size class could be fertilized, and small-sized larvae hatched from these eggs. To explain the alteration in egg size through divergence from amphidromous to landlocked populations, the role of batch allocation among oocytes is discussed.     

Upregulation and antiapoptotic role of endogenous Alzheimer amyloid precursor protein in dorsal root ganglion neurons

The amyloid precursor protein (APP) is a transmembrane protein whose abnormal processing is associated with the pathogenesis of Alzheimer's disease. In this study, we examined the expression and role of cell-associated APP in primary dorsal root ganglion (DRG) neurons. When dissociated DRG cells prepared from mouse embryos were treated with nerve growth factor (NGF), neuronal APP levels were transiently elevated. DRG neurons treated with an antibody against cell surface APP failed to mature and underwent apoptosis. When NGF was withdrawn from the cultures after a 36-h NGF treatment, virtually all neurons underwent apoptosis by 48 h. During the course of apoptosis, some neurons with intact morphology contained increased levels of APP immunoreactivity, whereas the APP levels were greatly reduced in apoptotic neurons. Furthermore, affected neurons contained immunoreactivities for activated caspase-3, a caspase-cleaved APP fragment (APPDeltaC31), and Abeta. Downregulation of endogenous APP expression by treatment with an APP antisense oligodeoxynucleotide significantly increased the number of apoptotic neurons in NGF-deprived DRG cultures. Furthermore, overexpression of APP by adenovirus vector-mediated gene transfer reduced the number of apoptotic neurons deprived of NGF. These results suggest that endogenous APP is upregulated to exert an antiapoptotic effect on neurotrophin-deprived DRG neurons and subsequently undergoes caspase-dependent proteolysis.     

Skip of the routine habitat in an amphidromous migration of ayu

Ayu Plecoglossus altivelis is a typical amphidromous fish with ontogenic requirements for habitats among lower reaches of a river, the marine coastal area, and middle reaches of a river at the immature adult stage. Mature fish that had a small body size like ordinary young were found around the spawning ground. In comparison with standard adults, the migratory histories of the dwarf adults were examined using otolith microchemistry analysis. Sr:Ca ratio estimated that the dwarf fish were exposed to saline or brackish water after once moving into the river, whereas the standard-size fish migrated upstream.     

Molecular cloning and characterization of prokineticin receptors

Recent studies have identified two novel biofunctional proteins, termed prokineticin 1/EG-VEGF and prokineticin 2, which were mammalian homologues of mamba MIT1 and frog Bv8. Prokineticins have been demonstrated to exert their physiological functions through G-protein coupled receptors (GPCRs). In this study, we report the molecular identification of two endogenous prokineticin receptors, designated PK-R1 and PK-R2, through a search of the human genomic DNA database. PK-R1, locating in chromosome 2, and PK-R2, locating in chromosome 20p13, shared 87% homology, which was an extremely high value among known GPCRs. In functional assays, mammalian cells expressing PK-Rs responded to prokineticins in a concentration-dependent manner. Tissue distribution analysis revealed that expression of PK-R1 was observed in the testis, medulla oblongata, skeletal muscle and skin, while that of PK-R2 showed preferential expression in the central nervous system. The tissue distribution of PK-Rs reported in this paper suggests that the prokineticins play multifunctional roles in vivo.     

Territorial defense of an excess food supply by an algal grazing fish, ayu

The size of the territory defended by the grazing fish ayu, Plecoglossus altivelis, often increases with decreasing intruder pressure. This territorial extension occurs even after additional growth of the fish reaches a plateau due to a surplus supply of algal food. This raises questions about the ecological advantages of defending an apparently enlarged territory. Enclosures were used to carry out observations on fish maintained as: (i) individuals with algae attached to the whole bottom area (2.4m²); (ii) individuals with algae covering 0.8m²; and (iii) with three conspecifics (competitive use) with algae attached to 2.4m². In the competitive use enclosures, one (occasionally two) fish that exclusively foraged the area appeared in each of the groups. Algal resources were sufficiently renewable that no significant difference in growth rate was detected between the dominants of the competitive groups and the two types of solitary enclosures, indicating that the defended area supplied algal resources that exceeded the dominants ability to grow. All the territorial holders realized an increase in relative body weight, suggesting the occurrence of inhibition, which corresponds to Verners concept of superterritory. However, as inferred from the pheophytin/chlorophylla ratios, algae within a territory showed less senescence, perhaps owing to cropping by the dominant, and this was considered to be an adaptive response by the fish to an unpredictable food supply. In conclusion, the ayu conditionally defends a territory for long-term benefits, and inhibition is a consequence of facultative territory size and not a cause of it.     

Nicotinamide mononucleotide supplementation reverses vascular dysfunction and oxidative stress with aging in mice

We tested the hypothesis that supplementation of nicotinamide mononucleotide (NMN), a key NAD⁺ intermediate, increases arterial SIRT1 activity and reverses age‐associated arterial dysfunction and oxidative stress. Old control mice (OC) had impaired carotid artery endothelium‐dependent dilation (EDD) (60 ± 5% vs. 84 ± 2%), a measure of endothelial function, and nitric oxide (NO)‐mediated EDD (37 ± 4% vs. 66 ± 6%), compared with young mice (YC). This age‐associated impairment in EDD was restored in OC by the superoxide () scavenger TEMPOL (82 ± 7%). OC also had increased aortic pulse wave velocity (aPWV, 464 ± 31 cm s^?1 vs. 337 ± 3 cm s^?1) and elastic modulus (EM, 6407 ± 876 kPa vs. 3119 ± 471 kPa), measures of large elastic artery stiffness, compared with YC. OC had greater aortic production (2.0 ± 0.1 vs. 1.0 ± 0.1 AU), nitrotyrosine abundance (a marker of oxidative stress), and collagen‐I, and reduced elastin and vascular SIRT1 activity, measured by the acetylation status of the p65 subunit of NFκB, compared with YC. Supplementation with NMN in old mice restored EDD (86 ± 2%) and NO‐mediated EDD (61 ± 5%), reduced aPWV (359 ± 14 cm s^?1) and EM (3694 ± 315 kPa), normalized production (0.9 ± 0.1 AU), decreased nitrotyrosine, reversed collagen‐I, increased elastin, and restored vascular SIRT1 activity. Acute NMN incubation in isolated aortas increased NAD⁺ threefold and manganese superoxide dismutase (MnSOD) by 50%. NMN supplementation may represent a novel therapy to restore SIRT1 activity and reverse age‐related arterial dysfunction by decreasing oxidative stress.     

Characterization of Pseudomonas aeruginosa phage KPP21 belonging to family Podoviridae genus N4‐like viruses isolated in Japan

Bacteriophages (phages) belonging to the family Podoviridae genus N4‐like viruses have been used as therapeutic agent in phage therapy against Pseudomonas aeruginosa infections. P. aeruginosa phage KPP21 was isolated in Japan, and phylogenetically investigated the phages belonging to this viral genus. Morphological and genetic analyses confirmed that phage KPP21 belongs to the family Podoviridae genus N4‐like viruses. Moreover, phylogenetic analyses based on putative DNA polymerase and major virion protein showed that P. aeruginosa phages belonging to the genus N4‐like viruses are separated into two lineages and that phage KPP21 is in the same clade as phage LUZ7.     

New haplotype and inter‐strain reproductive compatibility of Wolbachia‐uninfected alfalfa weevil,Hypera postica (Coleoptera: Curculionidae), in Japan

Hypera postica is a univoltine invasive pest of alfalfa, Medicago sativa, in North America. In Japan, H. postica was first found in 1982 from Fukuoka and Okinawa Prefectures and became a serious pest of Chinese milk vetch, Astragalus sinicus, cultivated as a honey source for humans and green manure for rice. In North America, three strains, Western, Eastern and Egyptian, have been identified and the Western strain is infected with Wolbachia, which causes complete inter‐strain reproductive incompatibility. In contrast, only Western and Egyptian strains had been reported throughout Japan and none of the Western strain examined for the Fukuoka populations in northern Kyushu was infected with Wolbachia. First, we screened populations from northern Kyushu collected since 1982 for geographical and chronological distribution of the Eastern strain. The Eastern strain has been found at low frequencies since 1985 and is still present in 2014. Second, we experimentally tested our hypothesis that inter‐strain crosses between uninfected Western‐strain males and Egyptian‐strain females should produce viable offspring. We crossbred virgin adults reared individually from field‐collected larvae and confirmed that the F₁ eggs of crosses between the Western‐strain males and the Egyptian‐strain females develop successfully into larvae.     

A New Heterotrophic Cryptomonad: Hemiarma marina n. g., n. sp.

We report a new heterotrophic cryptomonad Hemiarma marina n. g., n. sp. that was collected from a seaweed sample from the Republic of Palau. In our molecular phylogenetic analyses using the small subunit ribosomal RNA gene, H. marina formed a clade with two marine environmental sequences, and the clade was placed as a sister lineage of the freshwater cryptomonad environmental clade CRY1. Alternatively, in the concatenated large and small subunit ribosomal RNA gene phylogeny, H. marina was placed as a sister lineage of Goniomonas. Light and electron microscopic observations showed that H. marina shares several ultrastructural features with cryptomonads, such as flattened mitochondrial cristae, a periplast cell covering, and ejectisomes that consist of two coiled ribbon structures. On the other hand, H. marina exhibited unique behaviors, such as attaching to substrates with its posterior flagellum and displaying a jumping motion. H. marina also had unique periplast arrangement and flagellar transitional region. On the basis of both molecular and morphological information, we concluded that H. marina should be treated as new genus and species of cryptomonads.     

Differential expression of moesin in cells of hematopoietic lineage and lymphatic systems

 Moesin is a member of the ERM family consisting of ezrin, radixin, and moesin. The protein is located in the plasma membrane similarly to ezrin and radixin, and is thought to regulate cellular movements and morphological changes. Using monoclonal antibody CR-22, the specificity of which against human moesin was confirmed by immunoprecipitation and western blotting analysis, we immunohistochemically stained various formalin-fixed and paraffin-embedded human tissues, in particular, clots of bone marrow and lymphatic tissues, to examine moesin expression in cells of hematopoietic lineage and lymphatic systems. In the bone marrow, moesin was expressed in myeloid cells, while little staining was detected in erythroid cells. Moesin was highly expressed in both the center and the periphery of mature megakaryocytes. In the lymphatic tissues, moesin was strongly expressed by T-lymphocytes in the paracortex. In the mantle zone, the periphery of the germinal center, moesin was expressed by small lymphocytes which were identified as B-lymphocytes. Furthermore, in areas of inflammation, moesin was expressed in both the center and the periphery of neutrophils, whereas in some neutrophils in distant areas, moesin was localized at the cellular periphery. These results suggest that differential expression of moesin in these cells is involved in their morphology and specialized functions. Accepted: 19 December 1997