Elemental affinity for siderite found in a Japanese paddy subsoil

ABSTRACT

Siderite (FeCO₃), a type of carbonate mineral, is very occasionally recognized as a nodule in anoxic soils and sediments. During siderite formation, elements are expected to be accumulated or excluded between siderite and bulk soil. Therefore, we verified the affinity of 40 elements for siderite found in the gley horizon of a smectite-rich paddy field in northeastern Japan from the elemental concentration of the soil and the siderite dissolved in 2.88 mol L^?1 hydrochloric acid (10% HCl). The concentration ratio of the target element of the soil to the siderite was expressed by the product of the dimensionless R₀ value and ratio of titanium (Ti) concentration of the soil to the siderite (C_siderite /C_soil) = R₀ (Ti_siderite /Ti_soil). The affinity of each element for the siderite was analyzed by comparing the R₀ values. In comparison with Ti used as the reference element, P, Cr, Co and Mo were accumulated (R₀ > 1.0), and alkali metals, such as Li, Na and K, and chalcophile elements, such as Cu, Zn, Cd and Pb, tended to be equal or excluded from the siderite (R₀ ≦1.0). Of the group 2 elements, Ca, Sr and Ba were accumulated, while Mg was excluded. The affinity of Mn for siderite exceeded that of Fe as the main component of the siderite, which reflects the fact that siderite was formed in a fresh water condition. The siderite size did not influence the elemental affinity. Observation of micromorphology using a scanning electron microscope showed that the siderite nodules were aggregations of siderite particles and clays, suggesting that the siderite grew by taking in clay around it. The rare earth element (REE) distribution pattern showed a tendency not to increase linearly but to increase with forming a concave curve at the intervals of the four elements with the increase of atomic number (i.e. tetrad effects). Although these findings are from the lower horizons of anoxic soils, the elemental affinity for siderite of this study is useful in order to elucidate the complex elemental dynamics in the anoxic environment.     

Oxidative Stress Produced by Xanthine Oxidase Induces Apoptosis in Human Extravillous Trophoblast Cells

Oxidative stress has been recognized as an important factor in the pathophysiology of preeclampsia. It has been reported that the expression of xanthine oxidase (XO) in the cytotrophoblast and plasma hydrogen peroxide (H₂O₂) level are significantly higher in preeclamptics than in control women. The aim of this study was to clarify the biological influence of reactive oxygen species (ROS) produced by XO on extravillous trophoblast (EVT) cells. TCL1 cells, a human immortalized EVT cell line, were incubated with xanthine and XO (X/XO). We then measured the cell number, urate level of the culture media and the apoptotic cell ratio. Similar experiments were performed with additional administration of allopurinol, catalase, L-NAME or D-NAME, and with administration of H₂O₂ in substitution for X/XO. We assessed the effects of H₂O₂ on invasion ability, tube-like formation and protein expression of HIF1A and ITGAV of TCL1. Finally, the apoptotic cell ratio using primary cultured trophoblasts was measured following exposure to H₂O₂. X/XO decreased the relative cell number and increased the urate level and apoptotic cell ratio significantly. Elevation of the urate level and apoptotic cell ratio was attenuated by allopurinol and catalase, respectively. L-NAME and D-NAME had no influence on these effects. H₂O₂ also decreased the relative cell number. Pretreatment with H₂O₂ significantly inhibited the invasion ability, tube-like formation and HIF1A and ITGAV of TCL1. H₂O₂ also induced apoptosis in primary cultured trophoblasts. In conclusion, ROS produced by XO induced apoptosis and affected EVT function including invasion and differentiation.     

Season- and Age-related Reproductive Changes Based on Fecal Androgen Concentrations in Male Koalas,Phascolarctos cinereus

The purposes of the present study were to clarify age- and season- related androgen patterns, and to compare the reproductive physiology between Japanese captive koala populations and Australian populations. To measure fecal androgens, feces were collected from male koalas (4.2 to 13.8 years of age) kept in Japanese zoos. Fecal androgens were extracted with methanol from the lyophilized samples and determined by enzyme immunoassay using 4-androstene-3,17-dione antibody. Fecal androgen concentration in male koalas increased after sexual maturation and remained relatively high until old age. In the survey with the Japanese zoo studbook of koalas, copulation (conception) month showed a pyramid shape with a peak in March to June (60.7%) in koalas born and reared in Japanese zoos and from July to April with the highest concentration in September to January (69.7%) in Australian institutes. Japanese zoo koala populations have a characteristic physiological cycle adapted to Japan''s seasonal changes. The suitable month of year for copulation or conception in Japan is diametrically opposed to that in Australia. Mean fecal androgen concentrations by month in the males born and reared in Japan indicated annual changes with the highest concentration in May and the lowest value in November. Fecal androgen analysis may be a noninvasive alternative tool to monitor circulating testosterone and may be helpful in understanding reproductive activity and physiology in male koalas.     

Application of truncated nucleocapsid protein (N) for serotyping ELISA of murinae-associated hantavirus infection in rats

Truncated recombinant nucleocapsid proteins (trNs) that lack N-terminally located cross-reactive epitopes of four Murinae rodent-associated hantaviruses, Seoul virus (SEOV), Thailand virus, Hantaan virus (HTNV) and Dobrava-Belgrade virus, were produced by using a baculovirus expression system. ELISA with the trNs as antigens enabled serotyping of immune sera from rats experimentally inoculated with the corresponding hantaviruses with cut-off OD values of 60% of those of whole N of HTNV. The trN-based ELISA could serotype 12 out of 13 sera obtained from wild rodents (Rattus norvegicus) naturally infected with SEOV using the 60% cut-off value. These results indicate that screening with whole N followed by serotyping with trNs using a cut-off OD value of 60% of that of whole N is a useful method for serological surveillance of Murinae-associated hantavirus infection among rodents.     

Radioactive cesium and potassium in cattle living in the ‘zone in preparation for the lifting of the evacuation order’ of the Fukushima nuclear accident

To contribute to the reconstruction of livestock industry in Fukushima, radioactive cesium (¹³⁴Cs, ¹³⁷Cs) and potassium (⁴°K) were measured in various tissues of beef cattle living in an area where the evacuation order will be lifted in the near future. Radioactive cesium concentration was less than 100 Bq/kg in most of the samples. Skeletal muscles and kidney had the highest concentrations of radioactive cesium, whereas the liver was lowest among samples, excepting blood. Radioactive cesium concentration in the sirloin, tenderloin and top round was significantly higher than that in the neck muscle. Radioactive cesium concentration in the urine was not correlated with that in the blood, but the relationship became proportional when corrected with urinary ⁴°K. Distribution of ⁴°K was similar but not identical to that of radioactive cesium. These results suggest that it will be possible to resume livestock production in this area after the decontamination measures are completed and the evacuation order is lifted. Contamination level of living cattle can be estimated not only by blood samples but also by urine samples. If 50–100 Bq/kg of cesium is detected in the neck muscle at a slaughterhouse, the cattle should be reinspected using a sample from different muscles.     

When do rice terraces become rice terraces?

Paddy and Water Environment - Rice terraces located on sloped hills in mountainous areas are sometimes abandoned because of lack of labor and difficulties associated with cultivation. Recently,...     

A comparative epidemiological study of hantavirus infection in Japan and Far East Russia

Hantaviruses are causative agents of some severe human illnesses, including hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). The viruses are maintained by rodent hosts, and humans acquire infection by inhaling virus-contaminated excreta from infected animals. To examine the epidemiology of hantavirus infections in Japan and Far East Russia, we conducted epidemiological surveys in these regions. In Japan, anti-hantavirus antibodies were found in four rodent species, Clethrionomys rufocanus, Rattus norvegicus, R. rattus, and Apodemus speciosus. Although no new HFRS cases have been officially reported over the past 20 years in Japan, one member of the Japan Ground Self-Defense Force did test positive for hantavirus antibody. Repeated surveys in Far East Russia have revealed that two distinct hantavirus types cause severe HFRS in this region. Hantavirus sequences identified from A. peninsulae, fetal HFRS cases in Vladivostok, and Amur virus are highly similar to each other (> 92% identity), but they are less similar (approximately 84% identity) to the prototypical Hantaan virus, which is carried by A. agrarius. Phylogenetic analysis also indicates that Amur and A. peninsulae-associated viruses are distinct from Hantaan virus, suggesting that A. peninsulae is the reservoir animal for Amur virus, which causes severe HFRS. From HFRS patients in the Khabarovsk region, we identified viruses with nucleotide sequences that are more similar to Far East virus (> 96%identity) than to the Hantaan (88-89% identity) or Amur (81-83% identity) viruses. Phylogenetic analysis also indicates that the viruses from Khabarovsk HFRS patients are closely related to the Far East virus, and distinct from Amur virus.     

Obstructive nephropathy induced with DL-potassium hydrogen tartrate in F344 rats

We experienced obstructive nephropathy in F344 rats treated with DL-potassium hydrogen tartrate (PHT) in a 13-week oral repeated dose toxicity study. Six-week-old male and female F344/DuCrj rats were fed a diet containing up to 2.0% PHT for 13 weeks. Microscopical findings including irregular dilation of the distal tubule lumen, foreign body giant cells, inflammatory cell infiltration, and regeneration of renal tubules were observed focally or multifocally in the renal cortex and/or medulla in the 0.5% and higher dosage groups of both sexes. The severity of these lesions increased in a dose-dependent manner. In the urinalysis, an increase in protein and white blood cells or the concentration of tartaric acid was detected in the 0.5% PHT and higher dosage groups of both sexes or males, respectively, though conventional blood biochemical analysis did not indicate failure of renal function. These results indicate that the PHT induces obstructive nephropathy in rats. There were no other treatment-related changes in other organs.