Intracellular topography of rhodopsin bleaching

In a vertebrate eye, the photoreceptor cells are aligned so that most of the light passes through them lengthwise. At the light-transducing outer segment region of the photoreceptor, photons are absorbed in a time-varying, spatially dependent fashion. Because the transduction event is spatially localized around the site of photon absorption, the spatiotemporal patterns of light absorption in outer segments are an important receiver input characteristic. This aspect of receptor biophysics has now been measured; the results were consistent with a theoretical model proposed for bleaching of a pigment in an unstirred layer.     

fgf20 is essential for initiating zebrafish fin regeneration

Epimorphic regeneration requires the presence or creation of pluripotent cells capable of reproducing lost organs. Zebrafish fin regeneration is mediated by the creation of blastema cells. Here, we characterize the devoid of blastema (dob) mutant that fails fin regeneration during initial steps, forms abnormal regeneration epithelium, and does not form blastema. This mutation has no impact on embryonic survival. Dob results from an fgf20a null mutation, Y148S. Fgf20a is expressed during initiation of fin regeneration at the epithelial-mesenchymal boundary and later overlaps with the blastema marker msxb. Thus, fgf20a has a regeneration-specific requirement, initiating fin regeneration, and controlling blastema formation.     

Improvement of the NH2OH-HCl-HOAc method for extracting manganese and iron oxides in Japanese Andisols and other soil types in Japan

Abstract

We evaluated the validity of Tessier’s method as applied to the extraction of manganese (Mn) and iron (Fe) oxides in Japanese Andisols and other soil types in Japan. Using the original Tessier’s extractant mixture, 0.04 mol L^?1 hydroxylamine hydrochloride in 25% acetic acid (0.04 mol L^–1 NH₂OH-HCl in 25% HOAc), we found that substantial amounts of short-range-ordered Fe oxides were not extracted from allophanic Andisol samples and that considerable amounts of total Fe oxides were not extracted from all soil types. Relatively high extraction pH and large amounts of short-range-ordered Fe oxides in the Andisol samples might be responsible for incomplete extraction. Stoichiometric calculation indicated that the concentration of NH₂OH-HCl might be insufficient for complete extraction of Fe oxides. The extracted amounts of Mn and Fe increased with increasing concentration of NH₂OH-HCl in the extractant, and most of the Mn and Fe oxides in the soil samples, including samples with as much as 5.6% Fe, were extracted with 0.6 mol L^–1 NH₂OH–HCl in 25% HOAc. As judged from the simultaneous dissolution of aluminum (Al) and silicon (Si) minerals, extraction selectivity of Fe oxides with 0.6 mol L^–1 NH₂OH-HCl in 25% HOAc was comparable to that of the original Tessier’s method and better than that of a modified Community Bureau of Reference (BCR) sequential extraction procedure or a method using an extractant consisting of a mixture of oxalate and ascorbate, especially for Andisol samples.     

Distribution of CD163-positive cell and MHC class II-positive cell in the normal equine uveal tract

Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immunehomeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder,little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated thedistribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using animmunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used.Indirect immunofluorescence was performed using the primary antibodies CD163, MHC class II (MHC II) and CD20.To demonstrate the site of their greatest distribution, positive cells were manually counted in 3 differentparts of the uveal tract (ciliary body, iris and choroid), and their average number was assessed bystatistical analysis. The distribution of pleomorphic CD163- and MHC II-expressed cells was detectedthroughout the equine uveal tract, but no CD20-expressed cells were detected. The statistical analysisdemonstrated the distribution of CD163- and MHC II-positive cells focusing on the ciliary body. These resultsdemonstrated that the ciliary body is the largest site of their distribution in the normal equine uveal tract,and the ciliary body is considered to play important roles in uveal and/or ocular immune homeostasis. The dataprovided in this study will help further understanding of equine ocular immunity in the normal state and mightbe beneficial for understanding of mechanisms of ocular disorders, such as equine uveitis.     

Comparative analysis of the relationship between Cs and K in soil and plant parts toward control of Cs accumulation in rice

The effect of soil exchangeable potassium (K) and cesium (Cs) levels on Cs uptake and accumulation in different parts of rice (Oryza sativa L.) plants were examined using paddy soils with diverse exchangeable K and Cs in pot experiments. Aboveground Cs uptake decreased with higher exchangeable K and was linearly correlated with exchangeable Cs/K ratios, indicating competitive absorption of these elements by roots. Variation in Cs concentration in brown rice among soils was also related to the exchangeable Cs/K ratio. The exchangeable Cs/K ratio was positively reflected in the Cs/K concentration ratio in each plant part, with a specific slope, suggesting that Cs transport was coordinated with K transport and that there were regulated discriminations of Cs against K in the translocation process among parts. The Cs/K ratio was higher in brown rice and dead leaves than in active leaves, stems and husks. The distribution of Cs accumulation in brown rice was 14.5% on average, but it was variable and negatively related to K concentration in the stem. The Cs distribution in aboveground plant parts also decreased with higher K concentration in the root. These results imply the importance of the competitiveness with K in the root absorption and translocation of Cs within the plant. Based on the observed relationship between Cs and K, effective K management and other measures to control Cs accumulation in plant parts are discussed.     

Springiness of Pancake and Its Relation to Binding of Prime Starch to Tailings in Stored Wheat Flour

Wheat flours were stored at room temperature (15–25°C), 40, 60, 80, and 100°C for various times. The baking performance of these flours was then evaluated in terms of the springiness of pancakes (recovery from crushing). Baking performance improved with increased storage time at each temperature. Brabender Amylograph tests of the flours indicated that the onset temperature in viscosity decreased with increased storage time at each temperature. When the flours were fractionated by acetic acid (pH 3.5) with mortar and pestle, recoveries of the water-solubles and gluten fractions were unchanged, but recoveries of prime starch and tailings fractions changed remarkably with increased storage time. On the other hand, those changes were not observed when flours were fractionated with a Waring blender. The binding of prime starch to tailings was correlated significantly with baking performance.     

Heavy metal contamination of agricultural soil and countermeasures in Japan

Many heavy metals exist in minute amounts in natural agricultural soil. However, when their amounts exceed a certain level due to pollutants brought from outside, soil contamination occurs and agricultural products become contaminated. There have been many cases in Japan of heavy metal contamination originating from old mines and smelters, and soil contamination of agricultural land has become a social issue. In particular, cadmium (Cd) is one of the most harmful heavy metals. If agricultural products absorb an excessive amount of Cd, they may adversely affect people’s health, and therefore allowable concentrations are regulated by law. If agricultural land has become contaminated with Cd, measures for minimizing the absorption of Cd by agricultural crops are necessary; these include: (1) soil dressing, (2) water management (paddy field), (3) chemical cleaning of soil, (4) phytoextraction, and (5) use of different varieties and rootstock. Other heavy metals such as arsenic, lead, copper, zinc, and mercury also sometimes cause contamination of agricultural soil.     

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.     

Structural and physiological responses of the C4 grass Sorghum bicolor to nitrogen limitation

Nitrogen (N) is one of the major nutrients influencing photosynthesis and productivity of C₄ plants as well as C₃ plants. C₄ photosynthesis operates through close coordination between mesophyll (M) and bundle sheath (BS) cells. However, how the development of structural and physiological traits in leaves of C₄ plants is regulated under N limitation remains uncertain. We investigated structural and physiological responses of leaves of the NADP-ME-type C₄ grass Sorghum bicolor to N limitation. Plants were grown under four levels of N supply (.05 to .6 g N per 5-L pot). Decreasing N supply resulted in decreases in net photosynthetic rate, stomatal conductance, leaf N and chlorophyll contents, and the activity ratio of phosphoenolpyruvate carboxylase to ribulose 1,5-bisphosphate carboxylase/oxygenase and increases in δ¹³C values and photosynthetic N use efficiency. Low-N leaves were thinner and had smaller photosynthetic cells, especially in M, resulting in lower M/BS tissue area ratio, and contained smaller and fewer chloroplasts. The BS chloroplasts in the low-N leaves accumulated abundant starch grains. The number of thylakoids per granal stack was reduced in M chloroplasts but not in BS chloroplasts. The low-N leaves had thicker cell walls, especially in the BS cells, which might be associated with less negative δ¹³C values, and fewer plasmodesmata in the BS cells. These data reveal structural and physiological responses of C₄ plants to N limitation, most of which would be related to cellular N allocation, light use, CO₂ diffusion and leakiness, and metabolite transport under N limitation.