Secondary metabolites of cyanobacteriaNostoc sp.

Cyanobacteria attracted much attention recently because of their secondary metabolites with potent biological activities and unusual structures. This paper reviews some recent studies on the isolation, structural, elucidation and biological activities of the bioactive compounds from cyanobacteriaNostoc species.

     

Differences in seasonality and temperature dependency of stand transpiration and canopy conductance between Japanese cypress (Hinoki) and Japanese cedar (Sugi) in a plantation

In this paper, we present an investigation of interspecies differences in transpiration of the 2 most common plantation forest tree species in Japan, both in the family Cupressaceae with different northern limits of native distribution, Japanese cypress (Hinoki; Chamaecyparis obtusa Sieb. et Zucc.) and Japanese cedar (Sugi; Cryptomeria japonica D. Don). The stem sap flow rate was measured in 2 nearby stands of similar leaf area index in a 42‐year‐old plantation. Single‐tree and stand‐scale transpiration rates (E_tre and E_sta, respectively) were observed during an ideal autumn environment. At the stand scale, mean sap flux density of Hinoki was greater than that of Sugi, whereas total sapwood area per ground area was smaller in Hinoki than Sugi. Because the 2 variables had counterbalancing effects on transpiration, E_sta of Hinoki was similar to (94% of) that of Sugi. This offset was also found between the mean E_tre of the 2 species. E_sta was similar between the stands from May to October, whereas E_sta of Sugi was notably greater than that of Hinoki from February to April. During these 3 months, the difference in cumulative E_sta was 21.7 mm, which accounted for 79% of the difference in annual E_sta between Hinoki and Sugi (192 and 219 mm/year, respectively). We found that canopy conductance (G_c) and its sensitivity to the mean vapour pressure deficit during daylight hours in Sugi were particularly high in early spring, whereas those in Hinoki shifted gradually throughout the growing season. This difference was related to the optimal temperature of G_c in Sugi, which was approximately 10 °C lower than that in Hinoki. Our results suggest that plantations of water‐conserving species such as Hinoki produce timber slowly but yield water resources generously. Moreover, for plantations of trees sensitive to high temperature, such as Sugi, managers should be concerned about possible future decline caused by anticipated global warming.     

Re-ionizing the universe without stars

Recent observations show that the measured rates of star formation in the early universe are insufficient to produce re-ionization, and therefore, another source of ionizing photons is required. In this Letter, we examine the possibility that these can be supplied by the fast accretion shocks formed around the cores of the most massive haloes (10.5<log M/M _⊙<12) on spatial scales of order 1 kpc. We model the detailed physics of these fast accretion shocks, and apply these to a simple 1-D spherical hydrodynamic accretion model for baryonic infall in dark matter halos with an Einasto density distribution. The escape of UV photons from these halos is delayed by the time taken to reach the critical accretion shock velocity for escape of UV photons; 220 km s⁻¹, and by the time it takes for these photons to ionize the surrounding baryonic matter in the accretion flow. Assuming that in the universe at large the baryonic matter tracks the dark matter, we can estimate the epoch of re-ionization in the case that accretion shocks act alone as the source of UV photons. We find that 50% of the volume (and 5-8% of the mass) of the universe can be ionized by z∼7–8. The UV production rate has an uncertainty of a factor of about 5 due to uncertainties in the cosmological parameters controlling the development of large scale structure. Because our mechanism is a steeply rising function of decreasing redshift, this uncertainty translates to a re-ionization redshift uncertainty of less than ±0.5. We also find that, even without including the UV photon production of stars, re-ionization is essentially complete by z∼5.8. Thus, fast accretion shocks can provide an important additional source of ionizing photons in the early universe.     

Contents of hepatic and renal metallothioneins in Hyposarcus pardalis: for construction of biomarker for heavy metal contamination in environments

The pollution of water by heavy metals is one of the most serious problems in the developing countries, where watercourses play important roles in transport and economic activities. The aim of this study was to examine whether Hyposarcus pardalis, a fish species widespread in the freshwater environment in Indonesia, could be used as a biomarker for environmental pollution by metals. To this effect, the concentrations of metallothioneins and metals in the livers and kidneys of H. pardalis were measured. In addition, to clarify the relationship between metallothionein concentrations and metal exposure, the concentrations of metallothioneins and metals were determined in the liver and the kidney of fish exposed to 50 and 500 ppb Cu and 500 ppb Mn, compared with those kept in clean water. Sufficient concentrations of metallothionein were detected in fish captured from Lake Rawakalong located in an industrial area in the suburbs of Jakarta. The results of exposure experiments suggested that H. pardalis retained a history of pollution in its organs for a long duration, and the metals bound to metallothioneins in the liver and kidney could be replaced with Cu following exposure. In conclusion, the hepatic and renal metallothioneins in H. pardalis are a useful candidate biomarker for monitoring heavy metal contamination.     

Photoluminescence properties of anthophyllite

The photoluminescence (PL) spectra, optical excitation spectra and PL decay curves of anthophyllite from Canada were obtained at 300 and 10 K. The MnO content in the sample, determined using an electron probe microanalyzer, was high at 5.77 wt%. In the PL spectra obtained under 410-nm excitation, bright red bands with peaks at 651 and 659 nm were observed at 300 and 10 K, respectively. The origin of the red luminescence was ascribed to Mn²⁺ in anthophyllite from the analysis of the excitation spectra and PL decay times of 6.1–6.6 ms. In the PL spectra obtained under 240-nm excitation at 300 K, a small violet band with a peak at 398 nm was observed. On the violet band at 10 K, a vibronic structure was observed. The origin of the violet luminescence was attributed to a minor impurity in anthophyllite.     

Near-Infrared Colors of the Binary Kuiper Belt Object 1998 WW 31

We have measured near-infrared colorsof the binary Kuiper Belt object (KBO)1998 WW₃₁ using the Subaru Telescope withadaptive optics. The satellite was detectednear its perigee and apogee(0.18“ and 1.2” apart from the primary).The primary and the satellite have similar H–Kcolors, while the satellite is redder thanthe primary in J–H. Combined with the Rband magnitude previously published byVeillet et al., 2002, the color of the primaryis consistent with that of optically red KBOs. Thesatellite's R-, J-, H-colors suggest thepresence of ～1 μm absorption band dueto rock-forming minerals. If the surface of thesatellite is mainly composed by olivine, thesatellite's albedo is higher value than the canonicallyassumed value of 4%.     

Non-metamorphosed autochthonous Kuncha-Naudanda-Heklang Formations and their differences from those of the Kuncha nappe: A multichronological approach

Non-metamorphosed, autochthonous Lesser Himalayan sediments (LHS), which are correlated to the Kuncha and Naudanda Formations, were found in a narrow belt between the Main Boundary Thrust and the Lesser Himalayan Thrust at the base of the Kuncha nappe in southeastern Nepal. The autochthonous Naudanda Formation is comprised of cross-bedded and rippled orthoquartzite and yielded a maximum depositional age of 1795.1 Ma ±5.1 Ma using detrital zircons. Low-grade metamorphosed quartzite in the Kuncha nappe yielded a maximum depositional age of 1867.4 Ma ±3.4 Ma, although it is totally recrystallized. These ages and age distribution patterns of detrital zircon grains indicate that the meta-quartzite of the nappe is originally Naudanda Formation. A zircon fission-track age of the autochthonous Naudanda Formation shows partially annealed age of 864 Ma ±56 Ma, in contrast, that of the Kuncha nappe shows a totally annealed age of 11.9 Ma ±1.6 Ma. These results suggest that the autochthonous LHS have never undergone metamorphism during the Himalayan orogeny. We also discovered a non-metamorphosed Heklang Formation that rests on the Naudanda Formation, and designated it as a sub-type section on the basis of detailed lithostratigraphic study. It is characterized by black and light green slate with dolerite sills and ill-sorted quartzose sandstone, and correlated to the metamorphosed Dandagaon Phyllites in the Kathmandu area. Non-metamorphosed autochthonous formations distributed to the south of the nappe front suggest that they escaped from thermal metamorphism by hot nappe.     

A new ornithomimid dinosaur with North American affinities from the Late Cretaceous Qiupa Formation in Henan Province of China

A partial skeleton of the ornithomimid dinosaur, discovered from the Late Cretaceous Qiupa Formation of Luanchuan County, Tantou Basin, Henan Province, China, is described here and assigned to a new genus and species, Qiupalong henanensis, with unique features (a notch on the lateral surface of the lateral posterior process of the proximal end of tibia and a small pit at the contact between astragalus and calcaneum). A phylogenetic analysis in this study suggests that it is a derived ornithomimid and form a monophyly with North American ornithomimids (Struthiomimus altus and Ornithomimus edmontonicus), sharing two characters (straight pubic shaft and large acute angle between pubic shaft and boot). Some characters (small anterior process of the pubic boot and curved pedal unguals) are seen in basal ornithomimosaurs as well, but these features in Q. henanensis are reversal. Qiupalong is the first definitive ornithomimid from outside of the Gobi Desert and is the southern-most occurrence of Late Cretaceous ornithomimid from eastern Asia, demonstrating southern extension of ornithomimid distribution in Asia.