Physicochemical Properties and Molecular Structures of Starches from Millet (Pennisetum typhoides) and Sorghum (Sorghum bicolor L. Moench) Cultivars in Nigeria

Some physicochemical properties and molecular structures of starches from millet (Pennisetum typhoides, Doro and Gero) and sorghum (Sorghum bicolor, red and white) in Nigeria were examined. Starch granules of millet and sorghum were 3–14 μm and 4–26 μm in diameter, respectively. Millet cultivars had similar peak viscosities (204–205 RVU) on pasting, while sorghum showed similar minimum viscosities (155–156 RVU). The actual amylose content (%) calculated from iodine affinity (IA, g/100 g) was 20.1 and 21.4 for sorghum and 21.3 for millet. The IA of amylopectin was high (1.27–1.42) and its average chain lengths were 20–21 with β‐amylolysis limit of 56%. Amylopectins showed a polymodal molecular weight distribution on a molar basis. The distributions differed among the samples with a higher amount of larger molecules in Doro and red sorghum. Weight‐ and molar‐based distributions of debranched amylopectins on HPSEC were polymodal with weight‐based distribution showing presence of long chains. Peak DP values for A+B₁ and B₂+B₃ chain fractions were 13–16 and 42–43, respectively. The (A+B₁)/(B₂+B₃) ratio on molar basis (9.0–11.5) was similar to maize and rice amylopectins. Peak DP on molar‐based distribution for white sorghum and millet amyloses were similar (490–540) and the DP_n range was narrow (1,060–1,300), but weight‐based distribution profiles differed. The average chain lengths were 260–270 with 3.9–4.8 chains per molecule.     

Influence of puddling procedures on the quality of rice paddy drainage water

Drainage water quality in rice paddies was strongly influenced by the puddling of soil in the paddy fields by tractors and in response to opening of drainage gates. The concentrations of contaminants in drainage water increased rapidly when the puddling process began and were maintained at high concentrations throughout the puddling period. Moreover, the high concentrations did not decrease immediately after the puddling procedures ceased. Additionally, the ratio of dissolved nitrogen and phosphorous to total nitrogen and total phosphorous increased daily during the last half of the puddling period, due to discharge of chemical fertilizers with the drainage water. Also, the loads of particulate nitrogen and phosphorus discharged during the puddling period were larger than the loads discharge during irrigation. The discharge from paddy fields during puddling also increased the total annual contaminant load.     

拖拉机队列自动控制系统

为了提高拖拉机田间作业效率,开发了拖拉机队列自动控制系统.建立了拖拉机队列模型,设计了队列控制方法.首先应用三阶样条曲线拟合先行拖拉机的行驶位置点,动态生成跟踪拖拉机的参考路径.然后设计了最优路径跟踪器,用来引导跟踪拖拉机沿着参考路径行驶.在平坦的草地上进行了拖拉机队列的自动控制试验,试验结果表明,跟踪拖拉机能够成功沿着先行拖拉机的轨迹行驶,横向偏差的平均值和均方根值分别小于0.015 m和0.079m.     

Relationships among fine roots, fungal hyphae and soil microarthropods among different soil microhabitats in a temperate coniferous forest of Chamaecyparis obtusa

The relationships between roots and soil communities are not well understood. We used the ingrowth-core method with L-, FH-, and M-layer substrates to investigate the relationships among soil organic carbon, fine root biomass, hyphal length and the numbers of soil microarthropods. The study was carried out in a temperate forest of the arbuscular mycorrhizal conifer, Chamaecyparis obtusa. The relationships among fine roots, fungi and soil microarthropods were different among soil substrates and faunal taxa. Soil carbon contents, fine root biomass, hyphal length and soil-microarthropod numbers were the highest in the FH-substrate, and the lowest in the M-substrate. For each substrate, the total numbers of soil microarthropods did not positively correlated with soil organic carbon. A positive correlation between fine root biomass and the soil microarthropod numbers was significant only in the M-substrate, but not in the L- and FH-substrates. In M-substrates, strong positive correlations were found between fine root biomass or hyphal length and Mesostigmata or Oribatida numbers, but Collembola numbers were not corelated. Further studies of the regulation mechanism of soil food web structures should note that the soil microarthropods have different responses to C sources according to soil conditions and trophic interactions.     

Difference in content ratio of components among horse serum transferrin variants

Each of five genetic variants of horse serum transferrin (Tf), D, F, H, O, and R, was separated into two bands by polyacrylamide gel isoelectric focusing (PAGIEF). The more acidic band, termed component a, was more abundant than the other one, termed component b, in all variants. Components a and b of TFO variant were immunologically indistinguishable from each other by double immunodiffusion test. Determination of the content ratio of component a to component b in each variant revealed that the variants were classified into two groups: one group (D, F, and H) had a relatively high ratio within a range from 3.4 to 4.0 and the other group (O and R) had a relatively low ratio of 1.8 to 2.3. From these results and reference data on carbohydrate compositions of components a and b, it was proposed that there is a difference in glycosylation between the two groups.     

Antibody reactivity to Cryptosporidium parvum in saliva of calves after experimental infection

Antibodies against Cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. Salivary anti-C. parvum IgA antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. Salivary anti-C. parvum IgG antibody levels showed a gradual increase along with the change in IgA antibody levels during the infection. In contrast, serum anti-C. parvum IgA antibody levels showed only a slight increase between days 15 and 30 post-challenge. Serum anti-C. parvum IgG antibody levels rose on day 12 post-challenge and one calf maintained relatively high level up to the end of the experiment. In immunoblotting, an antigen with a molecular mass of 15 kDa was found to react strongly to salivary IgA antibody and a 27 kDa antigen to react to serum IgG antibody.     

Variation of tensile strength with annual rings for lumber from the Japanese larch

To examine the effectiveness of long rotation forestry and the potential of complete utilization of Japanese larch (Larix kaempferi Carriere), we designed a tensile test using the lumber from six 87-year-old sample trees. Results showed that strength properties of lumber varied greatly in the radial direction within trees, but all sample trees showed a similar trend. There was little difference in dynamic Young's modulus but a large difference in tensile strength (TS) between the lumber and small clear specimens from undestroyed parts of the lumber. These differences decreased with an increase in ring number and became constant after 30 years. The presence and distribution of knots markedly affected the TS; and among the knot indices, the knot number (Kn) and knot area ratio of a maximum single knot (Km) proved to be effective for explaining the effect of knots. The distribution of Kn and Km in the radial direction agreed with the variation of TS in the radial direction. By investigating the variation patterns of lumber and small clear specimens in the radial direction, it was found that the strength properties of both required a long time, about 30 years, to reach a relatively constant state.Part of this report was presented at the 49th annual meeting of the Japan Wood Research Society, Tokyo, April 1999     

A Spontaneous Oligodendroglioma in the Lumbar Portion of the Spinal Cord in a Young BrlHan:WIST@Jcl (GALAS) Rat

Oligodendroglioma is a rare tumor originating from oligodendrocytes found mainly in the cerebrum in aged rats. Only a few reports have shown spontaneous occurrence of this tumor in the spinal cord, and no report has mentioned its occurrence in young rats. We encountered a case of spontaneous oligodendroglioma in the lumbar portion of the spinal cord in a young (9 weeks old) female BrlHan:WIST@Jcl (GALAS) rat. Here we report the detailed histopathological and immunohistochemical characteristics of this case. No clinical signs, no gross lesions at necropsy, and no specific changes in hematology or blood biochemistry were observed. The tumor was located in the dorsal funiculus in the lumbar portion of the spinal cord and widely spread to the dorsal root nerve. The neoplastic cells showed a sheet-like growth pattern and had small round nuclei, clear cytoplasm and distinct cell borders that resulted in a honeycomb pattern. No mitotic figures or other histological lesions were observed. The neoplastic cells were positively stained for Olig2 and PCNA. The present case was considered to be a low-grade oligodendroglioma based on the histological and immunohistochemical features. To our knowledge, our case is considered to be extremely rare and the first report in a young rat.     

Mica polytypes: systematic description and identification

X-ray studies of mica specimens from a variety of geological localities show that biotite and certain lithium-rich mica samples are composed of a mixture of different polytypes. Many of the biotite structures are new complex polytypes not before reported. A new method of designating mica polytypes is proposed. Techniques are described for the systematic generation of all the possible layer-stacking sequences of mica polytypes and for the verification of the stacking sequences in newly discovered forms.