Intriguing olfactory proteins from the yellow fever mosquito,<Emphasis Type="Italic"> Aedes aegypti</Emphasis>

Four antennae-specific proteins (AaegOBP1, AaegOBP2, AaegOBP3, and AaegASP1) were isolated from the yellow fever mosquito, Aedes aegypti and their full-length cDNAs were cloned. RT-PCR indicated that they are expressed in female and, to a lesser extent, in male antennae, but not in control tissues (legs). AaegOBP1 and AaegOBP3 showed significant similarity to previously identified mosquito odorant-binding proteins (OBPs) in cysteine spacing pattern and sequence. Two of the isolated proteins have a total of eight cysteine residues. The similarity of the spacing pattern of the cysteine residues and amino acid sequence to those of previously identified olfactory proteins suggests that one of the cysteine-rich proteins (AaegOBP2) is an OBP. The other (AaegASP1) did not belong to any group of known OBPs. Structural analyses indicate that six of the cysteine residues in AaegOBP2 are linked in a similar pattern to the previously known cysteine pairing in OBPs, i.e., Cys-24–Cys-55, Cys-51–Cys-104, Cys-95–Cys-113. The additional disulfide bridge, Cys-38–Cys-125, knits the extended C-terminal segment of the protein to a predicted 2-helix. As indicated by circular dichroism (CD) spectra, the extra rigidity seems to prevent the predicted formation of a C-terminal -helix at low pH.Electronic Supplementary Material  Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

Concentrations of Heavy Metals in Muscle with Relation to the Growth of Two Marine Fish Species

Heavy metal concentrations in muscle and their relation to thegrowth of two marine fish species,including tonguefish( Cynoglossus arel) and mullet( Mugil cephalus),were studied. The samples were collected in Bach Dang estuary andconcentrations of heavy metals( As,Cd,Co,Mn,Cu,Zn,Pb,and V) in muscle of the fisheswere determined. The result showed that the accumulated trend of heavy metal is different between fish species. The concentration of As,Zn,Mn,V,Cu,Pb,Co and Cd in tonguefish were 73. 7 ± 30. 6,22. 82 ± 4.87,3. 44 ± 2. 13,1. 61 ± 0. 15,0. 71 ± 0. 13,0. 45 ± 0. 24,0. 03 ± 0. 02 and 0. 02 ± 0. 02 mg·g-1,respectively. Meanwhile the concentration of Zn,As,V,Mn,Cu,Pb,Co and Cd in mullet were 83. 41 ±19. 68,9. 78 ± 1. 92,1. 36 ± 0. 54,1. 29 ± 0. 51,0. 65 ± 0. 12,0. 42 ± 0. 20,0. 06 ± 0. 03 and0. 03 ± 0. 01mg·g-1,respectively. Comparison of metal levels among thesespecies indicated that the concentrations of As and Mn in tonguefish were significantly higher than those in mullet,whereas Zn levels in mullet were found to be higher than that in tonguefish. There is no significant differences of Cd,Co,Cu,Pb and V levels in muscle between two species. Significant inversed relationshipsbetween concentration levels of metals and lengths of tonguefish were found for Mn,Cu and Zn,butnot for As,Cd,Pb,and V. There were no significant relationships between the heavy metal concentrations and the length of mullet. In general,decreasesof the heavy metal concentrations corresponded to the increases of fish body lengths,particularly for As,Co,Cu,Mn and V and the exception for Cd. Terefore reduced risks were associated with consuming biggermullet fish,and increased risks of As and Cd were associated with consuming bigger tonguefish in Bach Dang river mouth.     

Trans-Pacific dispersal of loggerhead turtle hatchlings inferred from numerical simulation modeling

We used Lagrangian numerical simulations to examine the trans-Pacific dispersal processes of loggerhead turtle hatchlings. Ten thousand simulated particles were released from each of the three nesting regions in Japan and tracked for 5 years. Results showed many particles moving eastward, drifting in the Kuroshio Current followed by the Kuroshio Extension Current. However, no particles reached Baja California, a known feeding area, through passive processes, indicating that trans-Pacific transportation requires active swimming by turtles. The duration of the trans-Pacific dispersal was estimated to be at least 1.6–3.4 years, with some turtles drifting in the Kuroshio Countercurrent and remaining in the western Pacific even after 5 years. This indicates that as revealed by previous genetic studies, not all loggerheads always disperse along a trans-Pacific route. The findings showed that survival and expected growth rates varied widely according to ambient temperatures during drifting, which in turn depended on nesting location.     

Photosensitized degradation of Irgarol 1051 in water

Irgarol 1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine) is a herbicide analogue that is added to antifouling agents used on ships. Our former study on its degradation in sunlight suggested that unknown photosensitizers in natural waters accelerated the photodegradation to the degradation product, M1. In this study, the photodegradation of Irgarol in water was investigated in the presence of some photosensitizers. Test water containing Irgarol or M1, with or without photosensitizers, was irradiated with light from a UV-A fluorescent lamp for 48h. The concentrations of Irgarol and M1 in the test water were determined by HPLC after solid-phase extraction. M1 was more stable than Irgarol when irradiated in the presence of photosensitizers such as acetone, benzophenone, tryptophan, and rose bengal. Hydrogen peroxide (HP) accelerated the photodegradation of Irgarol, and the product M1 was degraded in the presence of more than 100mgl(-1) HP after 10h. Natural humic substances (NHS) also accelerated the photodegradation of Irgarol, but in this case, the product M1 persisted even when Irgarol was completely degraded. Photosensitized degradation of Irgarol by NHS may result in the accumulation of M1 in aquatic environments.     

Growth and Nitrogen Availability of Red Pine Seedlings under High Nitrogen Load and Elevated Ozone

To evaluate the effect of increasing nitrogen (N) deposition and tropospheric ozone (O₃) concentrations on N-saturated forest ecosystems, we investigated the response of Japanese red pine (Pinus densiflora), an N-saturation sensitive tree species, to increasing N load under elevated O₃ concentrations. One-year-old seedlings of red pine were treated with three levels of N supply (0, 50 and 100 mg N L^-1 fresh soil volume) under two levels of atmospheric O₃ concentration (< 5 and 60 ppb) for two growing seasons. Nitrogen treatment did not stimulate dry matter production of the seedlings. Growth inhibition was observed in the highest N treatment under low O₃ and in the two higher N treatments under elevated O₃. Irrespective of the O₃ concentration, increasing N supply negatively affected root growth and mycorrhizal development in fine roots, resulting in a reduction in P and Mg uptake from the soil. Net photosynthetic rate was significantly reduced by both the highest N treatment under low O₃ and the two higher N treatments under elevated O₃, together with decreased N-availability to Rubisco. Nitrogen assimilated from NO₃ ^- to amino acid in the needles was not affected by the treatments. However, needle protein concentration was reduced by the highest N-treatment under low O₃ and by the two higher N-treatments under elevated O₃. These results suggest that elevated O₃ potentially disturbs the N-availability in the form of protein including Rubisco, and may advance the negative effects of excessive N-deposition on N-sensitive plant species in N-saturated forests.     

Environmental geochemistry of technetium

Technetium-99 (⁹⁹Tc) is a radioactive isotope with a half-life of 2.13 × 10⁵ year. ⁹⁹Tc is a major radionuclide contaminant of concern for the world. Therefore, detailed understanding of ⁹⁹Tc environmental chemistry is important for protecting human and ecological health. Here, we review the aqueous geochemistry of ⁹⁹Tc, focusing on chemical properties and behavior of ⁹⁹Tc in the hydrosphere and pedosphere. We describe the general chemistry of Tc including coordination chemistry, isotope chemistry and solid-state chemistry. Then we present anthropogenic and indigenous sources of ⁹⁹Tc and their environmental distribution. We also discuss the radiotoxicity of ⁹⁹Tc and the use of ⁹⁹Tc for medical purpose. Tc biogeochemistry is described through sorption and desorption reactions at the mineral–water interface, thermodynamic of surface complexation, abiotic and biotic redox reaction of Tc(VII). Finally, we summarize the ⁹⁹Tc remediation technologies including cement waste forms, natural remediation, vitrification, nuclear waste transmutation.     

Growth history and inshore migration of the tropical eel, Anguilla marmorata, in the Pacific

A comparative study of the otolith microstructure and microchemistry of Anguilla marmorata glass eels in the western North Pacific (Japan, Taiwan, the Philippines, Indonesia) determined the timing of metamorphosis and age at recruitment to freshwater habitats with a view to learning about the early life history and recruitment of this species of tropical anguillid eel, which has a wide range throughout much of the western Pacific and parts of the Indian Ocean. Three new samples (from Japan, Taiwan, Indonesia) were analyzed and statistically compared along with two other previously published samples that were analyzed using the same techniques. Ages at metamorphosis and recruitment, respectively, were 123ᆡ.4 days (mean-SD) and 154ᆥ.0 days in specimens from Japan, 116ᆢ.6 days and 145ᆣ.6 days in those from Taiwan, 120ᆡ.0 days and 154ᆡ.5 days in the Philippines stock and 132Nj.7 days and 159ᆟ.7 days, and 120ᆣ.6 days and 152ᆣ.2 days in the Indonesian stock. The average duration of the period of metamorphosis estimated from otolith microstructure was very similar (15-17 days) in the specimens from all locations. A close linear relationship was found between the ages at metamorphosis and recruitment at all locations, suggesting that individuals that metamorphosed earlier were recruited to freshwater habitats at a younger age. Back-calculated hatching dates ranged over about 6 months of the year, suggesting that this species may spawn throughout much of the year. It is hypothesized that specimens from all four sites are from the same spawning population originating in a spawning area in the North Equatorial Current of the western North Pacific.     

A putative octopamine/tyramine receptor mediating appetite in a hungry fly

In the blowfly Phormia regina, experience of simultaneous feeding with d-limonene exposure inhibits proboscis extension reflex (PER) due to decreased tyramine (TA) titer in the brain. To elucidate the molecular mechanism of TA signaling pathway related to the associated feeding behavior, we cloned cDNA encoding the octopamine/TA receptor (PregOAR/TAR). The deduced protein is composed of 607 amino acid residues and has 7 predicted transmembrane domains. Based on homology and phylogenetic analyses, this protein belongs to the OAR/TAR family. The PregOAR/TAR was mainly expressed in head, with low levels of expression in other tissues at adult stages. Gene expression profile is in agreement with a plethora of functions ascribed to TA in various insect tissues. The immunolabeled cell bodies and processes were localized in the medial protocerebrum, outer layer of lobula, antennal lobe, and subesophageal ganglion. These results suggest that decrease of TA level in the brain likely affects neurons expressing PregOAR/TAR, causing mediation of the sensitivity in the sensillum and/or output of motor neurons for PER.