Ultraviolet visual pigment in a vertebrate: a tetrachromatic cone system in the dace

Microspectrophotometric measurements of optically isolated photoreceptors in the Japanese dace, a cyprinid fish, revealed four spectroscopically distinguishable cone pigments and one rod pigment. A visual pigment that absorbs in the near ultraviolet was found in small single cones.     

Climate-driven increases in global terrestrial net primary production from 1982 to 1999

Recent climatic changes have enhanced plant growth in northern mid-latitudes and high latitudes. However, a comprehensive analysis of the impact of global climatic changes on vegetation productivity has not before been expressed in the context of variable limiting factors to plant growth. We present a global investigation of vegetation responses to climatic changes by analyzing 18 years (1982 to 1999) of both climatic data and satellite observations of vegetation activity. Our results indicate that global changes in climate have eased several critical climatic constraints to plant growth, such that net primary production increased 6% (3.4 petagrams of carbon over 18 years) globally. The largest increase was in tropical ecosystems. Amazon rain forests accounted for 42% of the global increase in net primary production, owing mainly to decreased cloud cover and the resulting increase in solar radiation.     

Detection and monitoring of ongoing aseismic slip in the Tokai region,central Japan

Analysis of global positioning system data shows that the rate of crustal deformations in the Tokai region of Japan, a seismic gap area, changed over the past 18 months. Kalman filtering analysis shows aseismic slip on the plate boundary in the western Tokai region centered on Lake Hamana, adjacent to the anticipated Tokai earthquake source area. The cumulative moment magnitude reaches 6.7 in June 2002 with a relative slip increase northeast of Lake Haman from January 2002. An existence of aseismic slip in the western Tokai supports the hypothesis of a silent event as the cause of uplifting several days before the 1944 Tonankai earthquake.     

Carotenoid Nostoxanthin Production by Sphingomonas sp. SG73 Isolated from Deep Sea Sediment

Carotenoids are used commercially for dietary supplements, cosmetics, and pharmaceuticals because of their antioxidant activity. In this study, colored microorganisms were isolated from deep sea sediment that had been collected from Suruga Bay, Shizuoka, Japan. One strain was found to be a pure yellow carotenoid producer, and the strain was identified as Sphingomonas sp. (Proteobacteria) by 16S rRNA gene sequence analysis; members of this genus are commonly isolated from air, the human body, and marine environments. The carotenoid was identified as nostoxanthin ((2,3,2′,3′)-β,β-carotene-2,3,2′,3′-tetrol) by mass spectrometry (MS), MS/MS, and ultraviolet-visible absorption spectroscopy (UV-Vis). Nostoxanthin is a poly-hydroxy yellow carotenoid isolated from some photosynthetic bacteria, including some species of Cyanobacteria. The strain Sphingomonas sp. SG73 produced highly pure nostoxanthin of approximately 97% (area%) of the total carotenoid production, and the strain was halophilic and tolerant to 1.5-fold higher salt concentration as compared with seawater. When grown in 1.8% artificial sea salt, nostoxanthin production increased by 2.5-fold as compared with production without artificial sea salt. These results indicate that Sphingomonas sp. SG73 is an efficient producer of nostoxanthin, and the strain is ideal for carotenoid production using marine water because of its compatibility with sea salt.     

Zinc nutrition and levels of endogenous lndole‐3‐acetic acid in radish shoots

Radish (Raphanus sativus cv. Akamaru‐Hatsukadaikon) was grown for several experiments in a glasshouse with zinc (Zn) supply in the nutrient solution. Lack of Zn resulted in stunted growth and reduced leaf of radish shoots were observed. Two‐dimensional thin layer chromatography (TLC) and gas chromatography‐mass spectrometry (GC‐MS) analysis revealed the presence of endogenous indole‐3‐acetic acid (IAA) in Zn‐deficient radish shoots. An estimate has been made of alkali‐labile (1 and 7N NaOH) IAA in Zn‐deficient radish shoots with the use of gas chromatography (GC). The level of 7N NaOH‐labile IAA (peptidic + ester + free) and IN NaOH‐labile IAA (ester + free) in Zn‐deficient radish shoots was almost the same as that of control radish shoots. These results suggest that Zn nutrition did not affect the level of endogenous IAA in radish shoots.     

Nutritional Study of Silicon in Graminaceous Crops (Part 1)

Silicon in crop plants has been studied in various ways, for example, in elucidating its effects on phosphorus and nitrogen uptake by roots, or increase of resistance to diseases and insect pests, Graminaceous crops generally contain much more silicon in them than other families of plants, Remarkable effects of silicon application to plants On their growth appear especially in case they have contained about 5 to 10% of silicon before-hand. When silicon content in plants, on the other hand, is quite low, such as less than 0.5% for dry matter, plants show retardation of their grOwth at both vegetative and reproductive stages. It may be deduced that silicon applied to plants might play a role in different ways in cases where they have already had either considerable or quite small amounts of silicon. While the former case has been studied very much, extreme deficiency of silicon in plants has been investigated very little^1)-8). Experiments reported here were designed for elucidating roles of silicon in its defiCient plants and getting information about the essentiality of silicon for them.     

Nutritional Study of Silicon in Graminaceous Crops (Part 2)

It was reported in the previous paper₁₎ that rice plants showed retardation of their vegetative growth and decrease of degree of seed setting when their silicon content was extremely low. It was concluded from these facts that silicon might most probably be essential for rice. But physiological functions or behaviours of silicon in plants should be clarified in order to solve this problem completely. Uptake and disttibution of silicon in rice plants were first investigated here, especially compared with phosphorus. A possibility of using silicon radioactive isotope (₃₁Si) for this kind of experiment was also investigated. Although tracer techniques have been greatly developed in elucidating behaviours or physiological functions of various elements in plants, radioactive silicon isotopes have been used very little in this field of science because of this very short half lives. Recently Rothbuhr and Scott ²⁾ reported having used radioactive silicon isotope for uptake experiments by plants in Harwell, England. Since a nuclear reactor (JRR-I) in the Japanese Atomic Energy Research Institute started to work in 1959, radioactive isotopes which have rather short half lives have become available for plant experiments in Japan. Methods of preparation of ³¹Si for plant experiments were examined and by using ³¹Si it was studied how silicon was absorbed and translocated by rice and wheat under some particular environmental conditions, and also how the uptake and distribution of it in rice plants were affected by various kinds of metabolic inhibitors.     

Magnesium in barley plants on magnesium-deficient soils

Working with fused phosphate containing Mg, we have known some of the Mg-deficient areas in Shizuoka prefecture as a field problem. In these areas, crop plants develop visual hunger signs, resulting in restricted growth and reduced yield. The manurial effect of Mg-salt added or fused phosphate is remarkably excellent in these areas or soils.     

Importance of 2,4-DAPG in the biological control of brown patch by Pseudomonas fluorescens HP72 and newly identified genes involved in 2,4-DAPG biosynthesis

The Pseudomonas fluorescens strain HP72 used as biocontrol agent was isolated from the roots of creeping bentgrass on brown patch-suppressive soil. This strain can suppress brown patch disease caused by Rhizoctonia solani. The analysis of secondary metabolites from strain HP72 revealed that it produced known antifungal compounds, 2,4-diacetylphloroglucinol (2,4-DA-PG), HCN, and a fluorescent siderophore. In the present study, the Tn5inserted mutants of strain HP72, which did not show any antifungal activity, were selected. None of the mutants produced 2,4-DA-PG but they produced a fluorescent siderophore, while some strains produced HCN. Therefore, it is suggested that 2,4-DA-PG plays a major role in the biological control of brown patch disease caused by R. solani. In the genomic region where Tn5 was inserted, two open reading frames (ORFs A and B), which are not included in the 2,4-DAPG gene cluster of HP72, were detected. It was demonstrated that ORFs A and flare involved in the regulation of 2,4-DAPG biosynthesis.