Soil depth and soil water regime in a catchment where tropical dry evergreen and deciduous forests coexist

In several areas in Northeast Thailand, evergreen and deciduous forests coexist under uniform climatic conditions. To identify the factors that determine the distribution of these different forest types, we compared soil depth and soil physical properties between evergreen and deciduous forests, and monitored soil moisture conditions for a year in both forest types at the Sakaerat Environmental Research Station. The soil was significantly deeper under the evergreen forests (mean 97 cm) than under the deciduous forest (mean 64 cm). The soil under the evergreen forests retained much more water throughout the year than the soil under the deciduous forest, and there was also a clear tendency for the evergreen forests to occur in ravine areas, regardless of soil depth. It is possible that the evergreen trees can maintain transpiration during the dry season on thicker soils or in ravine areas, whereas shallower soils cannot provide enough water for these trees to maintain their evapotranspiration during the dry period. From the present study, we showed that soil water availability could be a significant factor determining the distribution of the deciduous and evergreen forests in our catchments.     

Changes in peripheral leukocyte populations of weak calf syndrome of Japanese black calves

To clarify the cellular immune condition in Japanese Black (JB) calves with a weak syndrome, peripheral leukocyte populations were analyzed by flow cytometry. Twenty JB calves were divided into two groups based on clinical observations; one group of calves was weak, because they had experienced an onset of diarrhea within 3 days after birth and needed treatment (Group 1 ;n=10), and the other group of calves was healthy (Group 2; n=10). With regard to leukocyte populations, CD8(+) cells and gamma delta T cells in Group 1 were markedly lower than those in Group 2 during the experimental periods. It is possible that immune-insufficiency might be based on T lymphocyte function in weak syndrome JB calves during the growth process.     

Detection of radiation-induced apoptosis using the comet assay

The electrophoresis pattern of apoptotic cells detected by the comet assay has a characteristic small head and spread tail. This image has been referred to as an apoptotic comet, but it has not been previously proven to be apoptotic cells by any direct method. In order to identify this image obtained by the comet assay as corresponding to an apoptotic cell, the frequency of appearance of apoptosis was examined using CHO-K1 and L5178Y cells which were exposed to gamma irradiation. As a method for detecting apoptosis, the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay was used. When the frequency of appearance of apoptotic cells following gamma irradiation was observed over a period of time, there was a significant increase in appearance of apoptosis when using the TUNEL assay. However, there was only a slight increase when using the comet assay. In order to verify the low frequency of appearance of apoptosis when using the comet assay, we attempted to use the TUNEL assay to stain the apoptotic comets detected in the comet assay. The apoptotic comets were TUNEL positive and the normal comets were TUNEL negative. This indicates that the apoptotic comets were formed from DNA fragments with 3'-hydroxy ends that are generated as cells undergo apoptosis. Therefore, it was understood that the characteristic pattern of apoptotic comets detected by the comet assay corresponds to cells undergoing apoptosis.     

Nucleotide Sequence of Citrus Tristeza Virus Seedling Yellows Isolate

The complete nucleotide sequence of a seedling-yellows-inducing isolate NUagA of Citrus tristeza virus (CTV) was determined. It consisted of 19302 nucleotides and contained 12 open reading frames (ORF) organized identically to those of previously sequenced isolates. This genome is the largest among the CTV genome sequenced so far ; it is 6 nucleotides (nt), 76 nt, 43 nt, and 53 nt longer than that of T36 (quick decline, Florida), VT (seedling yellows, Israel), T385 (mild, Spain), and SY568 (stem pitting, California), respectively. Sequence comparison of NUagA and the other isolates revealed approximately 90% identities throughout the 3′ half of the genome. The 5′ half of the genome was only about 70% identical to that of T36 but still high at about 90% to those of VT, SY568, and T385. Comparison of amino acid sequences on ORF1a encoding polyproteins, the most variable region, reflects the CTV isolate relationship ; NUagA is closely related to VT, SY568, and T385, but distantly related to T36. Received 29 May 2000/ Accepted in revised form 16 November 2000     

Determination of the distribution and reaction of polysaccharides in wood cell walls by the isotope tracer technique VIII: Selective radiolabeling of xylan in mature cell walls of magnolia (Magnolia kobus DC.) and visualization of its distribution by microautoradiography

To radiolabel xylan in mature cell walls selectively, magnolia (Magnolia kobus DC.) was administered withmyo-inositol-[2-³H] and allowed to metabolize for 1 month. The radiolabeled xylem tissue was then submitted to sulfuric acid hydrolysis and nitrobenzene oxidation. A large amount of radioactivity was found mainly in xylose, although slight activities were detected in glucose and in vanillin and syringaldehyde. The labeled tissue was submitted to a preparation of holocellulose followed by treatment with 24% potassium hydroxide (KOH). Radioactivity was distributed mainly in the KOH-soluble part of the holocellulose. These results indicate that most radioactivity was incorporated into xylan in the cell walls. The distribution of the incorporated radioactivity in the xylem tissue was visualized by microautoradiography. Radioactivities were distributed in the xylem more than 400 m from the cambium; and an inner layer of a secondary wall had formed at the labeled xylem. Consequently, selective radio-labeling of xylan was visualized in mature cell walls.Part of this report was presented at the 47th annual meeting of the Japan Wood Research Society, Kouchi, April 1997     

Structural conversion of the lignin subunit at the cinnamyl alcohol stage in Eucalyptus camaldulensis

The lignin biosynthetic pathway in Eucalyptus camaldulensis was investigated by feeding stems with deuterium-labeled precursor. Pentadeutero[,-D₂ OCD₃] coniferyl alcohol was synthesized and supplied to shoots of E. camaldulensis, and incorporation of the labeled precursor into lignin was traced by gas chromatography-mass spectrometry. In addition to the direct incorporation of labeled precursor into the guaiacyl unit, a pentadeuterium-labeled syringyl unit was detected. This finding indicates that the -deuterium atoms in the hydroxymethyl group of labeled coniferyl alcohol remain intact during modification of the aromatic ring. The relative level of trideuterium-labeled syringyl monomer (the result of conversion via the cinnamic acid pathway) was negligible, suggesting that the pathway at the monolignol stage is used for conversion of exogenously supplied precursor. Our results provide conclusive evidence of a novel alternative pathway for generation of lignin subunits at the monolignol stage even in plants that do not accumulate coniferin in lignifying tissues.     

Rapid method for detecting resistance to a QoI fungicide in Plasmopara viticola populations

BACKGROUND: The increasing occurrence of Qo inhibitor (QoI)‐fungicide‐resistant Plasmopara viticola (Berk. & MA Curtis) Berl. & DeToni populations is becoming a serious problem in the control of grapevine downy mildew worldwide. RESULTS: The authors have developed a rapid method for detecting resistance to a QoI fungicide, azoxystrobin, in P. viticola populations using the nested PCR‐RFLP method. With this method, a glycine‐to‐alanine substitution was discovered at codon 143 in the cytochrome b gene of P. viticola populations found in Japan. CONCLUSION: It is proposed that the nested PCR‐RFLP method is a high‐speed, sensitive and reliable tool for detecting azoxystrobin‐resistant P. viticola populations. Copyright © 2009 Society of Chemical Industry     

CO2稀释对生物质燃气燃烧与排放特性的影响

在一台火花点火发动机上,分别进行了CO2稀释对生物质燃气中可燃组分CH4、CO和H2的燃烧及排放性能影响的试验研究。研究结果表明,稀释燃烧能够有效降低NOx排放量;适当的稀释率对发动机的平均有效压力、循环变动以及热效率的影响较小,但过大的稀释率会导致部分燃烧。通过CO2稀释燃烧的手段,可以得到生物质燃气以一定热效率和NOx排放水平为指标的适宜燃料条件范围。     

An assessment of genetic diversity in wild and captive populations of endangered Japanese bitterling <Emphasis Type="Italic">Tanakia tanago</Emphasis> (Cyprinidae) using amplified fragment length polymorphism (AFLP) markers

ABSTRACT:   The Japanese bitterling Tanakia tanago (Cyprinidae) is on the verge of extinction in the wild, placing great importance on captive breeding programs for current conservation of the species. However, the loss of genetic diversity during captive breeding is an ongoing matter of concern. Since some captive populations have been almost monomorphic in mitochondrial DNA (mtDNA), this hampers assessments of their genetic diversity during captive breeding. To more accurately assess their genetic diversity, one wild and three captive populations were examined using amplified fragment length polymorphism (AFLP) markers. Estimates of average heterozygosity and nucleotide diversity ranged 0.0479–0.1920 and 0.0023–0.0088, respectively, enabling comparison of genetic diversity among the wild and captive populations, and among year-classes of captive populations. Significant differences in numbers of amplified fragments and proportions of polymorphic fragments were observed among year-classes of all populations. The indices of genetic diversity calculated from AFLP seemed to be, however, less sensitive to weak bottlenecks. No continuous decrease in genetic diversity in nuclear DNA was detected in presently captive populations. This supports the possibility of re-introduction of the captive populations into the original habitats, although survival and reproductive ability in the wild must be taken into consideration.     

Evaluation by weight change rate of dairy herd condition

The purpose of this study was to clarify whether weight change rate (WCR) is useful in evaluating herd health. Five herds (A, B, C, D, and E) were examined monthly for approximately 1 year to measure both WCR and BCS. WCR was calculated using the following equation: WCR (%) = (body weight of current month-body weight of the preceding month)/body weight of current month x 100. In addition, blood profiles were performed in each herd before and after calving. The incidence of periparturient diseases was higher in Herds A, B, and C compared with Herds D and E. Reproductive performance in Herds A and B was rather poor compared with Herds C, D, and E. There were significantly lower WCRs in Herd A compared with Herd C during the period of day -30 to day 30 after calving. According to the blood profiles, high levels of non-essential fatty acids (NEFA) were observed during the period of day -30 to -1 and high beta-hidroxybutyricacid (BHB) and low levels of glucose were observed at day 30 after calving in Herd A. A marked poor condition in Herd A during the peripaturient period was clearly expressed by low WCR in this experiment. WCR can express body condition of herds and is suggested to be a useful parameter in the determination of herd performance in field experiments.