Deep weathering and landscape evolution in a tropical plateau

The thick weathering profiles of humid tropical areas are an important, yet generally neglected, source of information on landscape evolution. Six complete profiles of the weathering mantle were sampled by drilling on the three stepped levels of the Campos do Jordão Plateau, on the NW flank of the Continental Rift of Southeastern Brazil. Mineralogical and micromorphological analyses of drill core samples, complemented by geochemical interpretations and by previous data on the upper saprolite, indicate continuity of a general lateritic trend during the entire process of mantle formation. Lateritization phases of different intensity were defined and considered to reflect adjustment to changes in environmental conditions created by the gradual uplift of the plateau to its present position. Older and more superficial materials related to intense lateritic weathering are characterized by allitization with direct formation of gibbsite from silicates, probably related to tropical climates existing immediately before the formation of the continental rift, during the Paleogene, and also before any significant increase in altitude. Monosialitization phase with general kaolinitization and restricted indirect formation of gibbsite from silicates could be associated to less aggressive climates that followed the Neogene (Miocene?) accentuation of uplift rates along the continental rift. The changes produced by uplift in the tropical climate eventually favored the development of a podzolization trend in soils above 1800 m.     

Effect of ground cover on splash and sheetwash erosion over a steep forested hillslope: A plot-scale study

The contributions and relationships of erosion by splash and overland flow over a steep slope in a Japanese beech forest in plots with different percentages of ground cover were examined. Three erosion plots (2 m wide × 5 m long) with average understory coverage of 1%, 45%, and 94% were installed. Sediment transported by rain splash and by overland flow was sampled separately. For the plots with sparse, moderate, and high understory coverage, the average proportions of splash soil to total soil erosion during the monitoring period were 16%, 32%, and 18%, respectively. A significant correlation between the amount of splash soil and precipitation was found in the plots with 1% and 45% understory coverage, whereas no statistical relationship was identified for the plot with high understory coverage. At the sparse ground cover plot showing the largest sediment movement, the contribution of splash transport decreased with increasing precipitation. The amount of sheetwash erosion was significantly correlated with the amount of splash soil under the condition of sparse ground cover. This relationship was more pronounced during high precipitation events and the rainy season. Splash contribution to the sediment transport was in the range of 0.8%–76.7%, 2.8%–81% and 2.1%–60.8% for plot with high, moderate and low ground cover, respectively. The sparse ground cover showed the largest variation of splash and sheetwash contribution in soil erosion. This variability was due to variation in ground cover and soil surface wetness condition which led to a variation of detachment and non-linear relationship of sheetwash splash.     

Polyphenol composition of a functional fermented tea obtained by tea-rolling processing of green tea and loquat leaves

Phenolic constituents of a new functional fermented tea produced by tea-rolling processing of a mixture (9:1) of tea leaves and loquat leaves were examined in detail. The similarity of the phenolic composition to that of black tea was indicated by high-performance liquid chromatography comparison with other tea products. Twenty-five compounds, including three new catechin oxidation products, were isolated, and the structures of the new compounds were determined to be (2R)-2-hydroxy-3-(2,4,6-trihydroxyphenyl)-1-(3,4,5-trihydroxyphenyl)-1-propanone 2-O-gallate, dehydrotheasinensin H, and acetonyl theacitrin A by spectroscopic methods. In addition, theacitrinin A and theasinensin H were obtained for the first time from commercial tea products. Isolation of these new and known compounds confirms that reactions previously demonstrated by in vitro model experiments actually occur when fresh tea leaves are mechanically distorted and bruised during the production process.     

Expressions of lipid oxidation markers, N(ε)-hexanoyl lysine and acrolein in cisplatin-induced nephrotoxicity in rats

The purpose of this study was to evaluate whether N(ε)-hexanoyl lysine (N(ε)-HEL) and acrolein reflect the severity of cisplatin-induced nephrotoxicity. Immunoexpression of N(ε)-HEL and acrolein in kidneys and their urinary concentration were examined up to day 4 post-cisplatin injection in rats. Cisplatin-induced tubular injury was observed histopathologically on days 2-4 after injection and became more severe time-dependently. On days 2-4, N(ε)-HEL and acrolein were immunostained in the cytoplasm of damaged tubular cells. Their immunostaining intensity and urinary levels increased as tubular injury became more severe. These results suggest that expressions of N(ε)-HEL and acrolein were associated with the pathogenesis of cisplatin-induced nephrotoxicity.     

Molecular and phenotypic characteristics of Salmonella enterica serovar 4,5,12:i:- isolated from cattle and humans in Iwate Prefecture, Japan

A total of 15 isolates of Salmonella enterica serovar 4,5,12:i:- obtained from diseased cows and patients in Iwate Prefecture, Japan, were characterized to clarify the genetic basis of this serovar. S. Typhimurium- specific IS200 was detected from all the isolates. A 94-kb plasmid and the spvB gene were detected from all but one of the 15 isolates. The results of PCR mapping of the fljAB operon and its flanking regions indicate that there are deletions or mutations in this chromosomal region. These data suggest that the 15 isolates are monophasic variants of S. Typhimurium. Epidemiological relationships between the isolates obtained from cattle and humans were not suspected based on the comparison of data employing plasmid profiling and pulsed-field gel electrophoresis.     

Mycoplasma ovis detected in free-living Japanese serows, Capricornis crispus

Nineteen blood samples collected from free-ranging wild Japanese serows, Capricornis crispus, between 2006 and 2008 in Iwate prefecture were examined for the hemoplasma infection by real-time PCR targeting the 16S rRNA gene. Five (26.3%) out of the 19 samples were positive in real-time PCR with an average melting temperature at 85.18 °C. The positive samples in the real-time PCR were reconfirmed by conventional PCR, and one of them was successful for direct DNA sequencing. The nucleotide sequence of the 16S rRNA gene of the representative stain was identical to that of Mycoplasma ovis. This was the first demonstration of hemotropic mycoplasma infections among the free-living Japanese serows in Japan.     

Expressions of protein oxidation markers, dityrosine and advanced oxidation protein products in acetaminophen-induced liver injury in rats

The purpose of this study was to evaluate whether dityrosine and advanced oxidation protein products (AOPP) were useful as biomarkers for monitoring the development of acetaminophen-induced liver injury. Dityrosine immunoexpression in the liver along with plasma AOPP concentration was examined up to 24 hr post-acetaminophen injection in rats. The histopathological changes in the liver appeared 3 hr after acetaminophen injection and became exacerbated with time. The immunohistological expression of dityrosine was also first detected in the damaged hepatocytes 3 hr after the injection and became more accentuated at 6, 12 and 24 hr in accompanying with the elevation of plasma AOPP concentration. These results suggested that dityrosine and AOPP expressions might be useful biomarkers for monitoring the development of acetaminophen-induced liver injury.     

Induction of a Th-1-biased IgG subclass response against equine herpesvirus type 1 in horses previously infected with type 4 virus

An immunoglobulin G (IgG) subclass response against equine herpesvirus type 1 (EHV-1) infection was investigated in horses that were na?ve to EHV-1/4 and those that had previously been exposed to EHV-4. The IgG subclass response was determined by an ELISA using EHV-1-specific recombinant gG protein as an antigen. In most horses na?ve to EHV-1/4, IgGa, IgGb, and IgG(T) were induced after experimental infection with EHV-1. In contrast, a subclass response dominated by IgGa and IgGb, with no apparent increase in IgG(T), was observed after EHV-1 infection in horses previously infected with EHV-4. Horses naturally infected with EHV-1 in the field showed similar responses. These results indicated that pre-infection with EHV-4 induced a Th-1-biased IgG subclass response against subsequent EHV-1 infection.     

Differential kinetic activities of glycerol kinase among African trypanosome species: phylogenetic and therapeutic implications

African trypanosome species are causative agents for sleeping sickness in humans and nagana disease in cattle. Trypanosoma brucei can generate ATP via a reverse reaction with glycerol kinase (GK) when alternative oxidase (AOX) is inhibited; thus, GK is considered to be a crucial target for chemotherapy combined with AOX. However, the energy metabolism systems of African trypanosome species other than T. brucei are poorly understood. Thus, GK genes were surveyed from genome databases and cloned by PCR from T. vivax and T. congolense. Then, recombinant GK proteins (rGK) of T. vivax, T. congolense and T. brucei were expressed and purified. Kinetic analysis of these rGK proteins revealed that the K(m) values of T. congolense rGK for ADP and G-3-P substrates were lower than those of T. vivax and T. brucei. The expression level of GK molecules was highest in T. congolense cells and lowest in T. vivax cells. Based on these results, effective combination dosages of ascofuranone, a specific inhibitor of AOX, and glycerol, an inhibitor of the GK reverse reaction, were determined by using in vitro-cultured trypanosome cells.     

Bovine oocytes in secondary follicles grow in medium containing bovine plasma after vitrification

There has been no culture system that supports the growth of bovine oocytes for more than 2 weeks. In the present study, bovine secondary follicles were cultured for 4 weeks, and the effects of supplemented protein components and FSH in the culture medium on the growth of the oocytes were examined. The effect of vitrification of secondary follicles on the subsequent oocyte growth was also examined. Secondary follicles (150 to 200 μm in diameter) containing growing oocytes (approximately 60 μm in diameter) were dissected from ovaries and cultured in a medium supplemented with FSH (0, 25 or 50 ng/ml) and one of the following four kinds of protein components: bovine serum albumin (BSA), bovine plasma (BPL), fetal calf serum (FCS) and bovine follicular fluid (BFF). In BSA- and BPL-supplemented media with 0 or 25 ng/ml FSH, more than 50% of follicles showed no degenerative signs during culture, and oocytes significantly increased in size after 4 weeks (P<0.05). Higher percentages of granulosa cell-enclosed oocytes were recovered from the follicles cultured in BPL-supplemented media with 0 and 25 ng/ml FSH, and the oocytes grew to 90 μm or more in diameter. In FCS- and BFF-supplemented media, FSH increased the numbers of degenerating follicles. Next, vitrified-warmed secondary follicles were cultured in BPL-supplemented medium. One third of the follicles showed no degenerative signs, and the oocytes increased in diameter to 88.8 ± 3.1 μm after 4 weeks of culture. These results suggest that a BPL-supplemented medium supports oocyte growth in bovine secondary follicles for 4 weeks, even after vitrification and warming of the follicles.