Seasonal changes in the deleterious effects of solar ultraviolet-B radiation on eggs of the twospotted spider mite, <Emphasis Type="Italic">Tetranychus urticae</Emphasis> (Acari: Tetranychidae)

Solar ultraviolet-B (UVB) radiation has deleterious effects on plant-dwelling mites. We assessed the biological effects of UVB radiation on the eggs of the twospotted spider mite, Tetranychus urticae Koch, under both near ambient (UV+) and UV-attenuated (UV−) conditions from spring to autumn and compared them to the effects of temperature and humidity. The ambient daily UVB irradiance increased from January to August and then decreased rapidly until December, whereas egg hatchability under UV+ was lowest in April (10.7%) and increased almost linearly until October (74.9–92.3%). In contrast, hatchability under UV− was consistently high (96.2–99.8%) through all seasons. For UV+, the stepwise multiple linear regression analysis supported the negative correlation of hatchability with cumulative UVB irradiance during egg periods (cumulative dose), but did not support that with the mean daily UVB irradiance (dose rate), suggesting that UVB-induced mortality in T. urticae eggs is cumulative dose dependent rather than dose rate dependent. The high mortality in April may have reflected the slower development caused by the relatively lower temperature and higher UVB radiation, increasing the cumulative dose, while the low mortality in October may have reflected the faster development caused by the relatively higher temperature and lower UVB radiation, decreasing the cumulative dose.     

Simultaneous determination of nefiracetam and its metabolites by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic assay was developed to simultaneously quantitate nefiracetam (NEF), a novel nootropic agent, and its three known oxidized metabolites (N-[(2,6-dimethylphenylcarbamoyl)methyl]succinamic acid (5-COOH-NEF), 4-hydroxy-NEF and 5-hydroxy-NEF) in human serum and urine. The quantitative procedure was based on solid-phase extraction with Sep-Pak C₁₈ and ultraviolet detection at 210 nm. The calibration curves of NEF and the metabolites were linear over a wide range of concentrations (0.5–21.5 nmol/ml for NEF and 0.4–9.5 nmol/ml for metabolites in serum and 4–86 nmol/ml for NEF and 8–190 nmol/ml for metabolites in urine). Intra- and inter-day assay coefficients of variation for the compounds were less than 10%. The limit of detection was 0.1 nmol/ml for NEF, 5-COOH-NEF and 4-hydroxy-NEF, and 0.2 nmol/ml for 5-hydroxy-NEF in both serum and urine. This method is applicable for the determination of NEF and its metabolites in human serum and urine with satisfactory accuracy and precision.     

Murine recombinant leukemia inhibitory factor modulates inhibitory effect of 1,25 dihydroxyvitamin D3 on alkaline phosphatase activity in MC3T3-E1 cells

We demonstrated murine leukemia inhibitory factor (mLIF) mRNA in osteoblastic MC3T3-E1 cells, but not mLIF in their conditioned medium. Recombinant mLIF had an inhibitory effect on alkaline phosphatase (ALP) activity, but not on DNA synthesis, in these mLIF-free cells. This inhibitory effect was not prostaglandin E2 dependent. mLIF also modulated the inhibitory effect of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] on ALP activity, partly via down regulation of 1,25(OH)2D3 binding sites. These results suggest that LIF may play a role in regulating osteoblast differentiation.     

Development of human health damage factors for PM<Subscript>2.5</Subscript> based on a global chemical transport model

Purpose

Health damage from ambient fine particulate matter (PM_2.5) shows large regional variations and can have an impact on a global scale due to its transboundary movement. However, existing damage factors (DFs) for human health in life cycle assessments (LCA) are calculated only for a few limited regions based on various regional chemical transport models (CTMs). The aim of this research is to estimate the human health DFs of PM_2.5 originating from ten different regions of the world by using one global CTM.

Methods

The DFs express changes in worldwide disability-adjusted life years (DALYs) due to unit emission of black carbon and organic carbon (BCOC), nitrogen oxides (NO _x ), and sulfur dioxide (SO₂). DFs for ten regions were calculated as follows. Firstly, we divided the whole world into ten regions. With a global CTM (MIROC-ESM-CHEM), we estimated the concentration change of PM_2.5 on the world caused by changes in the emission of a targeted precursor substance from a specific region. Secondly, we used population data and epidemiological concentration response functions (CRFs) of mortality and morbidity to estimate changes in the word’s DALYs occurring due to changes in the concentration of PM_2.5. Finally, the above calculations were done for all ten regions.

Results and discussion

DFs of BCOC, NO _x , and SO₂ for ten regions were estimated. The range of DFs could be up to one order of magnitude among the ten regions in each of the target substances. While population density was an important parameter, variation in transport of PM_2.5 on a continental level occurring due to different emission regions was found to have a significant influence on DFs. Especially for regions of Europe, Russia, and the Middle East, the amount of damage which occurred outside of the emitted region was estimated at a quarter, a quarter, and a third of their DFs, respectively. It was disclosed that the DFs will be underestimated if the transboundary of PM_2.5 is not taken into account in those regions.

Conclusions

The human health damage factors of PM_2.5 produced by BCOC, NO _x , and SO₂ are estimated for ten regions by using one global chemical transport model. It became clear that the variation of transport for PM_2.5 on a continental level greatly influences the regionality in DFs. For further research to quantify regional differences, it is important to consider the regional values of concentration response function (CRF) and DALY loss per case of disease or death.

     

High-performance liquid chromatographic method for determination of DX-9065a, a novel anticoagulant, in human urine and feces using cation-exchange solid-phase extraction

A simple HPLC method for determination of DX-9065a in human urine and feces was developed. The drug was extracted by Bond Elut CBA, a cation-exchange solid-phase extraction cartridge. The extracted drug was analyzed by HPLC with UV detection at 242 nm. With this extraction procedure, no interfering peaks were observed. The method developed was validated and showed adequate precision and accuracy. This method was applied to human clinical samples obtained from healthy Japanese volunteers who had orally received the drug. Using this method, the excretion profile of the drug in human after oral administration was revealed for the first time.     

Transient movement of helix F revealed by photo-induced inactivation by reaction of a bulky SH-reagent to cysteine-introduced pharaonis phoborhodopsin (sensory rhodopsin II).

Pharaonis phoborhodopsin (ppR) is a photosensor of negative phototaxis in Natronomonas (Natronobacterium) pharaonis, an alkalophilic halophile. This protein has seven transmembrane helices into which a chromophore, all-trans retinal, binds to a specific lysine residue (located in helix G)via a protonated Schiff base. Various mutants were engineered to have a single cysteine in the F-helix. In the presence of a bulky fluorescent SH-reagent, MIANS, (2-(4'-maleimidylanilino)naphthalene-6-sulfonic acid, illumination decreased the photoreactivity or flash-yield (absorbance deflection immediately after the flash) of the L163C ppR mutant (in which Leu-163 was replaced with Cys) without changing the photocycling rate. The fluorescence of the isolated protein increased with increasing illumination. These observations suggest that during photocycling, the space around Cys-163 in the F-helix might open, permitting reaction with the relatively large molecule. This reaction occurred only at the M-state and not at the O-state. The implications are discussed.     

The fine structure of the proliferative cells of the mouse intestine as revealed by electron microscopic autoradiography with 3H-thymidine

Summary The duodenal and colonic epithelia in mice were observed with electron microscopic autoradiography 2, 5 and 24 hours after a single injection of ³H-thymidine. After 2 hours, in the duodenum, silver grains are found in many undifferentiated cells, in a few young goblet cells, in some crystal-containing cells, and in some lymphocytes. In the colon after 2 hours silver grains are seen in some undifferentiated cells, and in many young goblet cells. Undifferentiated cells are characterized by a few short microvilli, poorly developed rough-surfaced endoplasmic reticulum, abundant free ribosomes, and a few apical moderately dense granules. In normal animals, absorptive cells seem to arise from undifferentiated cells, and goblet cells — from younger goblet cells. Undifferentiated cells could also become young goblet cells. Crystal-containing cells, which may not be of epithelial origin, proliferate in the epithelium in the adult animal.     

Response of cell surface glycosyl transferases to dibutyryl adenosine-3',5' cyclic monophosphate in virus-transformed and normal cells.

Galactosyl and sialyl transferases in the plasma membrane of SV40-transformed mouse cells were inhibited by 0.5 mM dibutyryl adenosine-3′,5′ cyclic monophosphate (db-cAMP) while those of normal cells did not respond to this compound. The differential effects of dibutyryl adenosine-3′,5′ cyclic monophosphate on the membrane-bound glycosyl transferases were observed both in isolated plasma membrane and in intact cell membrane. It is suggested that some of the morphological restorations of normal cell characteristics during reverse transformation are partly due to the direct effect of this compound on the cell membrane.