Turbid water induces refuge behaviour of a commercially important ayu: A field experiment for interstream movement using multiple artificial streams

Riverine systems are inherently dendritic in nature, and turbid water may not necessarily flow equally throughout an entire catchment. Tributaries have the potential to serve as refugia from temporarily turbid water in the main stem. As ayu (Plecoglossus altivelis) are one of the important species for the inland fisheries industry and recreational fishing, their behaviour in a branched river network is a primary concern. We released ayu with radio‐transmitting tags into two experimental streams that joined at a downstream pool. Turbid water was released into one of the streams, and we identified whether avoidance movement of ayu between the two experimental streams was triggered by flowing turbid water. The suspended solid concentration elevated rapidly after adding the turbid water and was maintained at more than 400 mg/L for 3 hr. Avoidance movement of ayu was triggered when the suspended solid concentration exceeded approximately 200 mg/L. Then, most ayu moved from the turbid stream to the nonturbid one, leading to a difference in ayu density between the two streams. Therefore, we demonstrated that turbid water induced interstream movement of a commercially important ayu as refuge behaviour, suggesting that river connectivity is important for the persistence of the ayu.     

Preparation of amphiphilic lignin derivative as a cellulase stabilizer

A polymeric amphiphile, PE-AL, was prepared from acetic acid lignin (AL) obtained by acetic acid pulping of birch under atmospheric pressure with polyethylene glycol diglycidyl ether (PE) as the crosslinker. The behavior of PE-AL solutions and the complex formation of PE-AL with protein were investigated to clarify the function of this novel lignin derivative. The reduced viscosity of the amphiphile in aqueous solution was low (<0.3dl/g), and it decreased with increasing concentration in dilute solution. This suggested that the PE-AL in aqueous solution has a structure similar to that of Einstein's sphere and shrinks upon hydrophobic interaction among the structural moieties in AL and the exclusive volume effect. The amphiphilic PE-AL obviously formed a complex with bovine serum albumin (BSA) at 4°C with a reaction time of about 1 week. After complex formation with cellulase for 1 week, the cellulase activity of the resulting complex is significantly enhanced and is preserved after recycling the complex for hydrolysis of cellulosic materials several times.Part of this work was presented at the 48th Annual Meeting of the Japan Wood Research Society, Shizuoka, April 1998     

Three-dimensional live imaging of bovine embryos by optical coherence tomography

While embryo transfer (ET) is widely practiced, many of the transferred embryos fail to develop in cattle. To establish a more effective method for selecting bovine embryos for ET, here we quantified morphological parameters of living embryos using three-dimensional (3D) images non-invasively captured by optical coherence tomography (OCT). Seven Japanese Black embryos produced by in vitro fertilization that had reached the expanded blastocyst stage after 7 days of culture were transferred after imaged by OCT. Twenty-two parameters, including thickness and volumes of the inner cell mass, trophectoderm, and zona pellucida, and volumes of blastocoel and whole embryo, were quantified from 3D images. Four of the seven recipients became pregnant. We suggest that these 22 parameters can be potentially employed to evaluate the quality of bovine embryos before ET.     

The Dnmt3b splice variant is specifically expressed in in vitro-manipulated blastocysts and their derivative ES cells

Manipulation of preimplantation embryos in vitro, such as in vitro fertilization (IVF), in vitro culture (IVC), intracytoplasmic sperm injection (ICSI), somatic cell nuclear transfer (SCNT) and other assisted reproduction technologies (ART), has contributed to the development of infertility treatment and new animal reproduction methods. However, such embryos often exhibit abnormal DNA methylation patterns in imprinted genes and centromeric satellite repeats. These DNA methylation patterns are established and maintained by three DNA methyltransferases: Dnmt1, Dnmt3a and Dnmt3b. Dnmt3b is responsible for the creation of methylation patterns during the early stage of embryogenesis and consists of many alternative splice variants that affect methylation activity; nevertheless, the roles of these variants have not yet been identified. In this study, we found an alternatively spliced variant of Dnmt3b lacking exon 6 (Dnmt3bΔ6) that is specific to mouse IVC embryos. Dnmt3bΔ6 also showed prominent expression in embryonic stem (ES) cells derived from in vitro manipulated embryos. Interestingly, IVC blastocysts were hypomethylated in centromeric satellite repeat regions that could be susceptible to methylation by Dnmt3b. In vitro methylation activity assays showed that Dnmt3bΔ6 had lower activity than normal Dnmt3b. Our findings suggest that Dnmt3bΔ6 could induce a hypomethylation status especially in in vitro manipulated embryos.     

Effect of protein hydrolysate from Antarctic krill meat on the state of water and denaturation by dehydration of lizard fish myofibrils

ABSTRACT: To utilize Antarctic krill as functional food, protein hydrolysates were prepared by enzymatic hydrolysis. Their effects on the state of water in myofibrils of lizard fish and dehydration-induced denaturation were compared with those from two species of shrimp, glucose, and sodium glutamate. Peptides are major components in hydrolysates, occupying approximately 85–93% of the total materials. The Antarctic krill protein hydrolysates stabilized the bonding of water molecules, leading to suppressed denaturation of myofibrils during the dehydration process. Similar effects were observed for shrimp protein hydrolysates. The effect of the hydrolysate was less than that by glucose and sodium glutamate.     

Preparation of board-like moldings from composites of isolated lignins and waste paper II: effect of inorganic salt addition on board performance and evaluation of practical use of MDF

Board-shaped composites with medium density (MDF) were prepared from isolated lignins and waste newspaper, in addition to preparation of the composites with high density (HB). The board properties of both composites concerning bending strength and water resistance were improved by the addition of hardwood acetic acid lignin (HAL). The internal bond strength and water resistance of MDF, in particular the degree of thickness swelling (TS), were also improved by prolonged molding time. Adding inorganic salts contributed to the improvement of TS. The effect depended on the charge of the cation. Considering practical utilization of lignin-based MDF as a structural material, its performance was evaluated by combination of the single-shear test of nailed joints and the modulus of rigidity. As a result, this MDF had sufficient strength to be utilized as an internal shear wall material. Therefore, lignin can be considered as an alternative to conventional adhesives for the production of boards such as HB and MDF.     

Preparation of activated carbon moldings from the mixture of waste newspaper and isolated lignins: mechanical strength of thin sheet and adsorption property

To expand the utilization of waste newspapers and lignin, activated carbon (AC) sheets, as an example of AC moldings, were prepared from those mixtures. The isolated lignins used were softwood and hardwood acetic acid lignins (SAL and HAL), softwood kraft lignin (KL), and wheat-straw lignin (WSL). The mixtures were molded into precursory sheets by thermal compression and then converted to AC sheets by carbonization and steam activation. The flexural strength of the precursory sheets was dramatically improved by additing the lignins compared to that of sheets without lignin. The strength of several sheets was more than 25 MPa. This suggested that lignins act as adhesives. SAL and HAL sheets with 40% newspaper were strengthened by the carbonization, whereas the strength of other lignin sheets was depressed. Finally, the AL-based AC sheets showed higher flexural strength (>6MPa) than others. Most of the AC sheets had adsorption ability comparable to that of commercially available AC powder and granules. The capacities were almost independent of paper content. Among the AC moldings tested, the AL-based AC sheets showed the fastest adsorption top-chlorophenol. Thus, viable AC moldings can be prepared from lignin-wastepaper mixtures, particularly SAL and HAL.     

Ultrastructural characteristics of two distinct gonadotropes (GTH I- and GTH II-cells) in the pituitary of rainbow trout Oncorhynchus mykiss

The salmonid pituitary produces two chemically distinct gonadotropins (GTHI and GTHII). Ultrastructural characteristics of GTHI- and GTHII-producing cells were studied in the trout pituitary with electronmicroscopic immunocytochemistry using antisera against salmon GTHIβ- and IIβ-subunits. In pituitaries from vitellogenic fish, GTHI-cells were characterized by numerous dilated cisternae of the granular endoplasmic reticulum (GER) and a small number of Iβ-positive granules (diameter, 100–300 nm), whereas GTHIIβ-immunoreactivity was found on granules (diameter, 200–400 nm) and large globules (diameter, 500–4000 nm) in apparently different cells (GTHII-cells). Distinct cellular distributions of GTHI and GTHII were maintained during gametogenesis, although morphological characteristics of GTHI- and GTHII-cells overlapped each other due to changes in number and size of the granules, globules and cisternae of the GER. Interestingly, the globules in the GTHI-cells were immunonegative for GTHIβ, although in the GTHII-cells they were always stained with GTHIIβ-antiserum. These results confirm that GTHIβ and GTHIIβ are synthesized in distinctly different cell-types in the salmonid pituitary and indicate that morphological characteristics cannot be used to distinguish these two cell-types.

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Résumé L'hypophyse des salmonidés produit deux gonadotropines (GTHI et GTHII) chimiquement distinctes. Les caractéristiques ultrastructurales des cellules produisant la GTHI et la GTHII ont été étudiées par immunocytochimie en microscopie électronique en utilisant des anticorps dirigés contre les sousunités GTHIβ et GTHIIβ de saumon. Chez les poissons en vitellogenèse, les cellules à GTHI se caractèrisent par un réticulum endoplasmique granulaire (REG) contenant de nombreuses citernes dilatées et un petit nombre de granules positives à la GTHIβ (diamètre 100–300 nm) tandis qu'une immunoréactivité à la GTHII était trouvée sur des granules (diamètre 200–4000 nm) et de grands globules (diamètre 500–4000 nm) dans des cellules apparemment différentes (cellules à GTHII). Des distributions cellulaires distinctes de la GTHI et la GTHII se sont maintenues à des stades plus avancées de la gamétogenèse, bien que les caractéristiques morphologiques des cellules à GTHI et GTHII se recoupent suite à des changements dans le nombre et la taiile des granules, des globules et des citernes du REG. II est à remarquer que les globules prśents dans les cellules à GTHI étaient immunonégatifs à la GTHIβ alors que dans les cellules à GTHII ils étaient toujours marqués par l'anticorps contre la GTHIIβ. Ces résultats confirment que, dans l'hypophyse des salmonidés, les GTHIβ et GTHIIβ sont synthetisées dans des types cellulaires différents et indiquent que des caractéristiques morphologiques ne peuvent être utilisées pour distinguer ces deux types cellulaires.

     

Utilization of wood cell wall components

This article summarizes current utilizations of wood cell wall components in relation to biorefinery of woody biomass as a separation method of its constituents. Especially, utilization of isolated lignins, involving transformation and molding, are demonstrated with respect to productions of carbon fibers and their further functionalization, such as developments of activated carbon fibers and electrodes for second battery and electric double-layer capacitor.