Enzymatic method for measuring the absolute value of oxygen concentration

An enzymatic method for measuring the absolute concentration of oxygen in aqueous solutions, using 4-hydroxybenzoate 3-monooxygenase and glucose oxidase, is described. The monooxygenase is used for quantitative oxidation of 4-hydroxybenzoate and NADPH with oxygen into 3,4-dihydroxybenzoate and NADP+; the amount of oxygen can be measured as the amount of NADPH decreased by the reaction. The monooxygenase reaction is performed in a syringe, a closed system. After the completion of the monooxygenase reaction, glucose oxidase is added to the assay solution to consume the oxygen from the atmosphere; this enables us to measure the NADPH concentration in the solution spectrophotometrically in an open system and to check the anaerobicity of closed systems. The oxygen concentrations at 25 degrees C of oxygen-saturated and air-saturated water were 1.10 and 0.23 mM, respectively. The value for argon-bubbled water was zero within the experimental error; this justifies the assay system. Thus, it is shown that a sample containing 8 microM-1.1 mM oxygen can be measured by this method.     

Therapeutic activity of plant-derived alkaloid conophylline on metabolic syndrome and neurodegenerative disease models

Increasing metabolic syndromes including type-2 diabetes mellitus, obesity, and steatohepatitis are serious problems in most countries in the world. Neurodegenerative diseases such as Alzheimer, Parkinson’s, and Huntington’s diseases are increasing in many countries. However, therapy for these diseases is not sufficient yet. Thus, effective chemotherapy for these diseases is being expected. Conophylline is an alkaloid isolated from the leaves of Ervatamia microphylla and related plants. It was found to induce beta-cell differentiation in the precursor pancreatic cells. Oral administration of this compound ameliorated type-2 diabetes mellitus model in mice and rats. Later, fibrosis of the pancreatic islets was found to be greatly reduced by conophylline in the pancreatic islets. It also inhibited chemically induced liver cirrhosis. Further study indicated that conophylline inhibited non-alcoholic steatohepatitis in the model mice. On the one hand, loss of autophagy often causes protein aggregation to give neural cell death. Conophylline was found to activate autophagy in cultured neural cells. Activation of autophagy ameliorated cellular models of Parkinson’s and Huntington’s diseases. Thus, conophylline is likely to be useful for the development of chemotherapy for metabolic and neurodegenerative diseases.     

Eribulin regresses a doxorubicin‐resistant Ewing's sarcoma with a FUS‐ERG fusion and CDKN2A‐deletion in a patient‐derived orthotopic xenograft (PDOX) nude mouse model

Ewing's sarcoma is a recalcitrant tumor greatly in need of more effective therapy. The aim of this study was to determine the efficacy of eribulin on a doxorubicin (DOX)‐resistant Ewing's sarcoma patient derived orthotopic xenograft (PDOX) model. The Ewing's sarcoma PDOX model was previously established in the right chest wall of nude mice from tumor resected form the patient's right chest wall. In the previous study, the Ewing's sarcoma PDOX was resistant to doxorubicin (DOX) and sensitive to palbociclib and linsitinib. In the present study, the PDOX models were randomized into three groups when the tumor volume reached 60 mm³: G1, untreated control (n = 6); G2, DOX treated (n = 6), intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, Eribulin treated (n = 6, intravenous (i.v.) injection, weekly for 2 weeks). All mice were sacrificed on day 15. Changes in body weight and tumor volume were assessed two times per week. Tumor weight was measured after sacrifice. DOX did not suppress tumor growth compared to the control group (P = 0.589), consistent with the previous results in the patient and PDOX. Eribulin regressed tumor size significantly compared to G1 and G2 (P = 0.006, P = 0.017) respectively. No significant difference was observed in body weight among any group. Our results demonstrate that eribulin is a promising novel therapeutic agent for Ewing's sarcoma.     

Hierarchical genetic structure of native masu salmon populations in Hokkaido,Japan

Identification of the spatial extent of genetic structuring that may be influenced by evolutionary, ecological and historical factors is critical for effective conservation or management strategies. Masu salmon Oncorhynchus masou is commonly distributed in Far East, however, many local populations have been under threats of decline due to habitat destruction, overexploitation, and genetic introgression. To reveal the spatial genetic structure of native masu salmon populations in Hokkaido, masu salmon samples were collected from 16 rivers in which there was no official record of artificial releases of any masu salmon stock and were analyzed using 15 microsatellite loci. A Bayesian assignment test revealed that masu salmon populations were divided into two genetically distinct groups: the northeastern and southwestern groups. For within-group genetic structure, all populations, except for geographically proximate populations, were significantly different from each other. AMOVA revealed that genetic variation at among-group level based on groups identified assignment test was greater than that of groups based on geographic locations. There was no significant IBD for the 16 populations. However, the Mantel test revealed significant IBD for the northeastern group, but did not for the southwestern group. This study suggested that native masu salmon populations in Hokkaido exhibit a hierarchical genetic structure that is largely a result of their precise homing behavior. The results of this study also highlight the importance of defining populations by using genetic data rather than by using predefined populations based on geographic locations for the correct determination of genetic structure.     

A non-coat protein synthesized in tobacco mesophyll protoplasts infected by tobacco mosaic virus

Summary A high molecular weight protein unrelated to the viral coat was detected in tobacco mesophyll protoplasts infected by tobacco mosaic virus.     

Light, nutrients and primary productivity in Lake Biwa: An evaluation of the current ecosystem situation

Simple correlation and multiple regression analyses were performed to examine the relationship between primary productivity and environmental factors in the north basin of Lake Biwa. The primary production rates used in the analyses were estimated monthly or bimonthly during the growing season (April–November) in 1992, 1996 and 1997 with the ¹³C method. Elemental (C, N and P) contents of seston were used to assess nutrient conditions. Analyses revealed that 86% of variance in depth-integrated primary production rates (areal PP) can be explained by changes in light intensity, and sestonic C, N and P concentrations. Water temperature had no effect on areal PP. To assess relative effects of light and nutrients on PP, the P:B ratio was estimated by normalizing PP with sestonic C. The areal P:B ratio correlated most significantly with the sestonic N:P ratio, followed by light intensity. When regression analyses were made at each depth, however, the P:B ratio correlated significantly only with the sestonic N:P ratio at 0 and 1 m depths, while light intensity was also incorporated into the regressions at deeper than 2.5 m. In these regressions, the P:B ratio was negatively correlated with sestonic N:P ratio but positively with light intensity. The results suggest that the primary production rate in this lake was mainly limited by P relative to N supply rates, but was not free from light limitation in a large part of the epilimnion. In Lake Biwa, the vertical water mixing regime as well as the nutrient supply seem to be important in determining the growth and composition of primary producers, since the surface mixing layer extends into 10–15 m depths during most of the growing season.     

Linking microhabitat availability and local density of rainbow trout in low-gradient Japanese streams

Quantification of reach-based microhabitat availability for rainbow trout (Oncorhynchus mykiss), considering their microhabitat requirements in two low-gradient streams, northern Japan, was attempted to test for habitat space limitation of local trout density. Underwater observations revealed that fish selected microhabitats of moderate current velocity, relatively greater depth and shorter distance to overhead cover in both streams, although habitat features used and available differed slightly between the streams. Habitat space for fish potentially available in the channel environment was evaluated using principal component analysis (PCA) of both available and used microhabitat. A close relationship was evident in both streams between reach-based microhabitat availability and fish density, which was assessed by a three-pass removal method. Direct estimates of fish microhabitat availability using PCA can contribute to accurate predictions of local fish density and provide insight into the mechanisms responsible for fish–habitat relationships in streams.     

Age-based demography and reproductive biology of three <Emphasis Type="Italic">Epinephelus</Emphasis> groupers, <Emphasis Type="Italic">E. polyphekadion,E. tauvina,</Emphasis> and <Emphasis Type="Italic">E. howlandi</Emphasis> (Serranidae), inhabiting coral reefs in Okinawa

The demography and reproductive biology of three Epinephelus groupers (Serranidae), namely E. polyphekadion, E. tauvina, and E. howlandi in the Yaeyama Islands, Okinawa, were examined based on age assessment using otoliths and gonadal histology. The maximum ages for these three species were 26 year, 23 year, and 17 year. The von Bertalanffy growth functions were also determined for each species. The size and age at 50% female maturity were estimated to be 358 mm in total length (TL) and 6.0 year for E. polyphekadion, 371 mm TL and 6.7 year for E. tauvina, and 327 mm TL and 4.1 year for E. howlandi, respectively. Significant differences between the sexes in size and age frequencies were found in all three species, with males being larger and older than females, or transitional individuals. These results strongly indicated that the population of these three grouper species showed monandric protogynous hermaphroditism. The sex ratios of E. polyphekadion and E. tauvina were biased in favor of females, but that of E. howlandi was equivalent between sexes. The relative sizes of ripe testes indicated that the intensity of sperm competition varied among species suggesting different mating system of each species. Reproductive seasonality was similar among species, with active vitellogenesis coinciding with the annual rise in water temperature. The active spawning period was determined to be between April and May for E polyphekadion, in May for E. howlandi, and from March to June for E. tauvina.