A new method to quantify how water repellency compromises soils' filtering function

Soil water repellency (SWR) is known to lead to preferential flow and to degrade the soil's filtering efficiency. However, no method is available to quantify directly how SWR affects the transport of reactive solutes. We propose a new method for conducting solute transport experiments in water‐repellent soils. It involves sequentially applying two liquids, one water, the other a reference fully wetting liquid, namely aqueous ethanol, to the same intact soil core with air‐drying between liquids. We applied this approach to quantify the impact of SWR on the filtering of the herbicide 2,4‐Dichlorophenoxyacetic acid (2,4‐D) in two Andosols. In batch experiments conducted prior to the transport experiments, 2,4‐D sorption was not influenced by aqueous ethanol for one soil. However, sorption in the second soil followed the co‐solvency theory, which predicts decreasing sorption with increasing solvent fractions. Thus, sorption experiments are necessary to complement our new method. Breakthrough curves were characterized by preferential flow with large initial concentrations, tailing and a long prevalence of solutes remaining in the soil. In the soil in which 2,4‐D sorption was unaffected by aqueous ethanol, SWR increased 2,4‐D losses by four and 50 times in the first 5‐mm outflow compared with the 2,4‐D losses with water. After 50‐mm outflow, the 2,4‐D losses were similar for one core, but in the other core they were still about four times greater with water than with aqueous ethanol. This method to quantify the reduction of the soil's filtering efficiency by SWR is needed for assessing the increased risk of groundwater contamination by solutes exogenously applied to water‐repellent soils.     

Characteristics of frozen-thawed spermatozoa cryopreserved with different concentrations of glycerol in captive Japanese black bears (Ursus thibetanus japonicus)

Seven mature Japanese black bears were used as semen donors, and a total of 7 semen samples collected from the animals by the electroejaculation method were cryopreserved in liquid nitrogen. Egg yolk-TRIS-citrate-glucose extender was used, and the effects of different final concentrations of glycerol, at 4-12% (v/v), on frozen-thawed spermatozoa were examined. No significant difference was observed in percent motility or percent abnormal morphology of frozen-thawed spermatozoa among the different glycerol concentrations. Percent viability and percent intact acrosomes of spermatozoa cryopreserved with 4 and 6% glycerol were significantly higher than those with 10 and 12% glycerol. These results suggest that a suitable glycerol concentration for freezing Japanese black bear semen within the range tested would be 4-6%.     

Identification of QTL controlling post-flowering period in soybean

The length of the reproductive period affects the grain yield of soybean (Glycine max [L.] Merr), and genetic control of the period might contribute to yield improvement. To detect genetic factor(s) controlling the reproductive period, a population of recombinant inbred lines (RILs) was developed from a cross between Japanese landrace ‘Ippon-Sangoh’ and, Japanese cultivar ‘Fukuyutaka’ which differ in their duration from flowering to maturation (DFM) relative to the difference in the duration from sowing to flowering (DSF). In the RIL population, the DFM correlated poorly (r = −0.16 to 0.34) with the DSF in all field trials over 3 years. Two stable QTLs for the DFM on chromosomes (Chr-) 10 and 11 as well as two stable QTLs for the DSF on Chr-10 and -16 were identified. The QTL on Chr-11 for the reproductive period (designated as qDfm1; quantitative trait locus for duration from flowering to maturation 1) affected all three trials, and the difference in the DFM between the Fukuyutaka and Ippon-Sangoh was mainly accounted for qDfm1, in which the Fukuyutaka allele promoted a longer period. qDfm1 affected predominantly the reproductive period, and thus it might be possible to alter the period with little influence on the vegetative period.     

High susceptibility of Djungarian hamsters (Phodopus sungorus) to the infection with Babesia microti supported by hemodynamics

As the comparative study was carried out on the susceptibility by the pursuit of parasitemia among the Djungarian, Syrian, and Chinese hamsters as well as BALB/c mice infected with the Syrian hamster-adapted Babesia microti strain, and Djungarian hamsters showed the highest parasitemia among them. Then, the other hematological parameters were pursued in the Djungarian hamsters infected with the hamster-adapted B. microti strain. Remarkable symptoms observed were hemoglobinuria clinically, anemia hematologically, and splenomegaly macroscopically during all over the observation period for 24 weeks post infection (PI). Parasitemia began to rise at 2 weeks and peaked at 4 weeks PI. After that, parasitemia decreased gradually but was maintained with a level of about 10% on average until 24 weeks PI at the end of the experiment. A decrease in the RBC count, Hb, and PCV, and an increase in the reticulocyte and WBC counts due to the development of immature neutrophils, lymphocytes and monocytes were recognized together with a rise of parasitemia. The hamsters had macrocytic hypochromic anemia due to the increase of MCV and the decrease of MCHC in the growth phase of the parasite. It was considered that the Djungarian hamsters will be useful for the infection examination, isolation, maintenance, and passage of B. microti in laboratory.     

Susceptibility of Chinese hamsters (Cricetulus griseus) to the infection of Babesia microti

Chinese hamsters were examined for the susceptibility to the infection with Babesia microti based on the hematological parameters during the course of infection. A marked decrease in the RBC count, Ht value, Hb concentration, and an increase in WBC count due to the development of neutrophils or monocytes were recognized with the progress of parasitemia. Remarkable clinical findings were anemia and persistent infection with a low level of parasite burden in the chronic and convalescent stages. From these findings, it was concluded that Chinese hamsters were susceptible to infection with B. microti and would be useful for infection examination with the parasite.     

Effects of introgressions from <Emphasis Type="Italic">Festuca pratensis</Emphasis> on winter hardiness of <Emphasis Type="Italic">Lolium perenne</Emphasis>

Previous studies reported that some genotypes with introgressed Festuca chromosome segment(s) in Lolium genome showed enhanced winter hardiness compared to Lolium. The aim of this study was to search comprehensively for the Festuca pratensis chromosome regions affecting winter hardiness-related traits when introgressed into the Lolium perenne genome. Association between F. pratensis introgression and winter hardiness-related traits (fall and winter hardiness indexes, early-spring dry matter yield, and freezing tolerance) were screened in the diploid introgression populations (n = 203) that had some F. pratensis chromosome segments introgressed. Eighty-four intron markers corresponding to unique rice genes randomly distributed across the genome were used for genotyping. Winter hardiness of almost all plants in the introgression populations was lower than that of the F. pratensis and triploid hybrid parents, but the average was higher than that of L. perenne. A significant positive effect of F. pratensis introgression on early-spring dry matter yield was detected on chromosome 7. This quantitative trait locus (QTL) was confirmed by linkage analysis using a backcross population with F. pratensis introgression in the target region of chromosome 7. However, the contribution of the newly identified QTL was rather small (6.7–9.6%), suggesting that superior winter hardiness of F. pratensis compared to L. perenne is conferred by multiple small-effect QTLs. We also detected a previously unreported negative effect of Festuca introgression on winter hardiness. Newly obtained QTL information in this study would contribute to the design of Festuca/Lolium hybrid breeding.     

Rainfall interception in a moso bamboo (Phyllostachys pubescens) forest

In recent years, moso bamboo (Phyllostachys pubescens) forest areas in Japan have rapidly expanded, and bamboo is now invading nearby natural or plantation forests. To date, only one study has examined the rainfall interception of a moso bamboo forest. In that study, it was reported that the interception ratio (interception/rainfall) of the bamboo forest did not exceed the interception ratios of other natural and plantation forests (n = 4) in Japan. To expand the current state of knowledge about rainfall interception of bamboo forests, we measured throughfall and stemflow at another bamboo forest site. Annual rainfall (Rf), throughfall (Tf), and stemflow (Sf) during the measurement period were 2,105, 1,556, and 322 mm, respectively. Annual rainfall interception at the plot (I) was 228 mm. Tf/Rf, Sf/Rf, and I/Rf were 73.9, 15.3, 10.8%, respectively. I/Rf was less than 20% throughout the year except in October, the month with lowest rainfall. We also summarized rainfall interception data from 19 other natural and plantation forests. The I/Rf value of our site did not exceed the I/Rf values of these natural and plantation forests (n = 19). Our data will be useful for assessing changes in water resources that result from replacement of natural or plantation forests by bamboo forests.     

Seasonal changes of azimuthal,radial, and tree-to-tree variations in sap flux affect stand transpiration estimates in a <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> forest,central Taiwan

Stand transpiration (E) estimated using the sap flux methods is affected by the azimuthal, radial, and tree-to-tree variations of sap flux. Although several studies have examined the relative importance of the three variations in estimating E, the seasonality of the three variations remains unknown. In the current study, we attempted to clarify whether the relative importance of these three variations could show seasonal changes. Using sap flux data measured in a subtropical cloud forest from August 2010 to July 2011, we calculated the differences resulting from omitting the three variations in estimating E. The effects of the three variations in estimating E showed seasonality. The azimuthal and tree-to-tree variations were more pronounced during winter, whereas the radial variation was more pronounced during summer. However, the effect of tree-to-tree variation was consistently much larger than the other two variations throughout the study period. The tree-to-tree variation is more important in estimating E monthly, seasonally and annually than both the azimuthal and radial variations, although all three variations have shown seasonality. In addition, the sensor allocation for summer would be acceptable for the practical estimation of E if aiming at the long time scale.     

Genetic analysis of antixenosis resistance to the common cutworm (Spodoptera litura Fabricius) and its relationship with pubescence characteristics in soybean (Glycine max (L.) Merr.)

The common cutworm (CCW, Spodoptera litura Fabricius) is one of the most serious pests of soybean (Glycine max (L.) Merr.). Previously, two quantitative trait loci (QTLs) for antibiosis resistance to CCW, CCW-1 and CCW-2, were detected in the resistant cultivar Himeshirazu. In this study, we conducted an anti-xenosis bioassay using a recombinant inbred population derived from a cross between a susceptible cultivar Fukuyutaka and Himeshirazu to perform QTL analysis. Two QTLs for antixenosis resistance, qRslx1 and qRslx2, were identified on Chrs 7 and 12, and the resistant alleles of qRslx1 and qRslx2 were derived from Himeshirazu and Fukuyutaka, respectively. The position of qRslx1 is similar to that of CCW-1. We also analyzed pubescence characteristics because they have been reported to be associated with soybean insect resistance. Two QTLs for pubescence length (on Chrs 7 and 12) and two QTLs for pubescence density (on Chrs 1 and 12) were identified. The pubescence QTLs on Chrs 7 and 12 were located near qRslx1 and qRslx2, respectively. These results suggest that the antixenosis resistance could be controlled genetically by the identified QTLs and that the pubescence characteristics might contribute to the soybean antixenosis resistance to CCW.     

Molecular cloning and biochemical characterization of medaka (Oryzias latipes) lysosomal neu4 sialidase

Glycoconjugates are known to be involved in many physiological events in vertebrates. Sialidase is one of the glycosidases, which removes sialic acid from glycoconjugates. In mammals, the properties and physiological functions of sialidases have been investigated, while there is little understanding of fish sialidase. Here, to investigate the significance of fish neu4 sialidase, neu4 gene was cloned from medaka brain mRNA and identified. Sialidase-specific motifs (GPG, YRVP and Asp-Box) were well conserved in the medaka neu4 polypeptide. Optimal pH of medaka neu4 sialidase was 4.6, but its activity was sustained even at neutral and weak alkaline pH. The neu4 considerably cleaved sialic acid from 4-methylumbelliferyl-N-acetyl-α-d-neuraminic acid and sialyllactose, but not from ganglioside and fetuin, which are good substrates for human NEU4. neu4 activity was mostly detected in mitochondria/lysosome fraction after biochemical fractionation, and indirect immunofluorescence assays revealed neu4 localization in lysosome in neu4 overexpressed cells. Next, developmental change in medaka neu4 and other sialidase mRNA levels were estimated by real-time PCR. Each sialidases showed different expression patterns in embryonic development: neu4 was up-regulated at late developmental stage in embryo, and neu3a mRNA level was quite high in 0.5 dpf. On the other hand, neu3b expression was drastically increased after hatching, suggesting that each sialidase may play a different role in embryonic development.