Accumulation of calcium,magnesium, potassium and sodium with growth of individual leaves,petioles and stems of cucumber plants

Abstract

Accumulation of Ca, Mg, K and Na in each individual leaf, petiole and stem of the cucumber plant (Cucumis sativus L. cv. Kasairaku) was investigated in relation to the growth of these organs under water culture condition. Growth of each individual organ followed a sigmoidal curve showing two distinctive phases, the exponential and stationary phases. Accumulation patterns of these major cations showed a elose relationship with the growth characteristics of the organs.

1) Leaf Although the rate of accumulation of the cations declined during the stationary phase of growth, both Ca and Na accumulated in all the leaves throughout the whole period of growth. A higher Ca content was observed in the older leaves while the younger leaves showed a higher Na content. Mg and K accumulated during the exponential phase, whereas no appreciable accumulation was observed during the stationary phase.

2) Petiole and stem. Accumulation of Ca, Mg and Na continued throughout the whole period of growth. No deeline in the rate of accumulation of these cations was observed during the stationary phase unlike in the leaf, whereas K accumulation was observed only during the exponential phase of growth, as in the leaf.

All three organs showed that the content of these cations in each individual organ decreased during the exponential phase of growth. The rate of decrease was greater in younger organs than in older ones.     

Preparation of heavy meromyosin from the autolyzed squid mantle muscle homogenate

ABSTRACT:   Incubation of squid mantle muscle homogenate caused a selective cleavage of myosin into heavy meromyosin (HMM) and light meromyosin (LMM). HMM was isolated from the incubated homogenate by using ammonium sulfate fractionation. The purified HMM retained two types of light chain components. Its Mg²⁺-ATPase activity with or without F-actin showed a Ca-sensitivity. HMM was cleaved into subfragment-1 and subfragment-2 upon chymotryptic digestion with or without Ca²⁺, possessing different light chain composition. Two types of light chain component were kept intact when digested in the presence of Ca²⁺. Ca²⁺ stabilized HMM especially in a bound form to F-actin.     

Effects of night‐time light intensity on the survival rate and stress responses in juvenile Pacific bluefin tuna Thunnus orientalis (Temminck and Schlegel)

Land‐based cultured juvenile Pacific bluefin tuna Thunnus orientalis (PBT) have high mortality rates due to collisions or contacts with tank walls after about 30 days of hatching. To determine the effect of night‐time lighting on their survival, juvenile PBT were reared under four different night‐time light intensities (0, 5, 15 and 150 lx) for 9 days, followed by a 3‐day observation period. High‐intensity, night‐time lighting (150 lx) significantly improved the survival rate (75.8%; P < 0.001) compared with the unlit control group (0 lx, 64.3%). The survival rate in the high‐intensity group decreased after the end of the lighting period. Lighting did not influence whole‐body cortisol levels, glucose levels, or diel changes in plasma cortisol levels. In contrast, the survival rates of fish exposed to light intensities between 5 and 15 lx were slightly lower than that of the unlit control group. These results suggest that providing night‐time lighting of 150 lx or higher is an effective method for reducing the mortality of cultured PBT.     

Myosin denaturation in heated myofibrils of scallop adductor muscle

The thermal inactivation of Ca²⁺ ATPase of scallop myofibrils (0.1 M KCl, pH 7.5) was found to be unaffected by the presence of Ca²⁺. Monomeric myosin content and salt solubility decreased much faster than Ca²⁺ ATPase inactivation in both Ca and EDTA media, which was well explained by faster denaturation of the rod portion than subfragment-1 of myosin. In contrast, when the myofibrils were heated at 0.5 M KCl, a slow decrease in salt solubility was observed, which was also explained by slow denaturation of the rod portion of myosin. Myofibrils from scallop smooth muscle showed the same denaturation pattern as those from adductor muscle. These results show that mollusk myosin is not always stabilized by Ca²⁺.     

Heat- and light-treatment change the visible fluorescence of Akoya cultured pearls

We exposed Akoya cultured pearls separately to heat (60–120 °C) and artificial light to investigate changes to fluorescence in the visible range and yellowing. We found that for both heat-treated and light-treated pearls, the fluorescence peak shifted from 480 to 430 nm with an increase in fluorescence intensity. This change in intensity was more prominent in heat-treated pearls, with the initial speed of increase rising with treatment temperature; treatment at 100 °C caused the greatest increase in fluorescence intensity. However, aminoguanidine suppressed the heat-induced change in the fluorescence of an ethylenediaminetetraacetic acid–soluble nacreous layer matrix. These results suggest that the heated-induced changes in the fluorescence of Akoya cultured pearls were caused largely by a buildup of fluorescent advanced glycation end products through the Maillard reaction. Although heat treatment led to a large increase in fluorescence intensity of the peak at approximately 430 nm in a deoxygenized environment, hardly any change in fluorescence intensity was observed after light treatment in this environment. Moreover, a new shoulder peak appeared at about 460 nm after light treatment. These results suggest that the Maillard reaction was not a major factor in the light-induced changes in the fluorescence of Akoya cultured pearls.     

Visual spectral sensitivity of photopic juvenile Pacific bluefin tuna (Thunnus orientalis)

Although Pacific bluefin tuna is a species that relies on vision, its photopic visual function is not well known; we therefore recorded electroretinograms to investigate photopic spectral sensitivity in juveniles of this species (49-81?days post-hatch; standard length 74-223?mm). The peak spectral sensitivity wavelength was 505?nm. We estimated that two (λ(max)?=?512-515?nm and 423-436?nm) or three (λ(max)?=?512-515?nm, 423-436?nm, and 473?nm) types of cone visual pigments contribute to photopic vision; these spectral sensitivities are adapted to surface water habitats in clear ocean and coastal water.     

Effect of titanium surface calcium and magnesium on adhesive activity of epithelial-like cells and fibroblasts

In the present study, we investigated the hydrothermal treatment of titanium with divalent cation solutions and its effect in promoting the adhesion of gingival epithelial cells and fibroblasts in vitro. Gingival keratinocyte-like Sa3 cells or fibroblastic NIH3T3 cells were cultured for 1 h on experimental titanium plates hydrothermally-treated with CaCl(2) (Ca) or MgCl(2) (Mg) solution, or distilled water (DW). The number and adhesive strengths of attached cells on the substrata were then analyzed. The number of Sa3 cells adhering to the Ca- and Mg-treated plates was significantly larger than in the DW group, but the strength of this adhesion did not differ significantly between groups. In contrast, NIH3T3 cell adhesion number and strength were increased in both the Ca and Mg groups compared to the DW group. Fluorescent microscopic observation indicated that, in all groups, Sa3 had identical expression levels of integrin β4 and development of actin filaments, whereas NIH3T3 cells in the Ca and Mg groups displayed much stronger punctate cytoplasmic signals for vinculin and more bundle-shaped actin filaments than cells in the DW group. As a result, it was indicated that the hydrothermal treatment of titanium with Ca or Mg solution improved the integration of soft tissue cells with the substrata, which may facilitate the development of a soft tissue barrier around the implant.     

Towards integrated research in fisheries science

In this paper we present a call for a re-directing fisheries science towards an integrated scientific activity which includes the trajectory of fish from eggs and their life underwater to consumption on the table. We propose that integrated research in fisheries science be defined as “interdisciplinary research for society and human well-being which deals with the sustainability of dynamic fisheries systems, taking various knowledge, values, and needs into account.” As an integrative discipline, fisheries science offers many advantages to overcoming the limitations of the traditional sciences. The ability to conduct traditional research activities based on each academic discipline is a prerequisite to participating in integrated research. However, “additional processes” are needed, such as the introduction of new integrated thinking, joint determination of the research framework, mutual learning by participating researchers, interaction with stakeholders, among others. Integrated research in fisheries science would allow overall influences to be analyzed, including exogenous factors such as environmental changes and other marine industries. Walleye pollock Theragra chalcogramma provides a good model species for analyzing future scenarios of the structure of the industry as well as potential strategies for addressing and considering the effects of other highly fluctuating resources. One of the most challenging topics is identifying possible paths from a depleted stock to its future recovery. Scientific analyses on “How fast?” “Who should bear the costs?” “When it will occur”, etc., should be conducted by close interactions with stakeholders.     

Laboratory observations on the vertical swimming behavior of Japanese common squid Todarodes pacificus paralarvae as they ascend into warm surface waters

This study examined the effect of warm temperature on the survival of paralarvae of Japanese common squid Todarodes pacificus and on their swimming behavior as they ascended to the surface. Observations were conducted on paralarvae in Petri dishes and in 85-cm-tall, cylindrical tanks that had a warmer upper layer and cooler lower layer separated by a small thermocline. Paralarvae were obtained through artificial fertilization and reared in Petri dishes at six experimental temperatures between 20.9 and 30.4 °C. Paralarvae reared at lower temperatures survived longer than those reared at warmer temperatures, and survival decreased at temperatures above 24 °C. When the mean temperatures in the upper layer of the tanks were 24.4–26.0 °C, the paralarvae ascended through the thermocline to the surface, but when the mean temperatures in the upper layer were 29.7–29.8 °C, paralarvae stopped ascending at the thermocline. These results show that paralarvae have a temperature preference but ascend to the surface in the unfavorable temperature range. The results suggest that increasing surface temperatures at spawning grounds will negatively affect both the survival and behavior of T. pacificus paralarvae.