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.     

Formation of follicular cysts in cattle and therapeutic effects of controlled internal drug release

Follicular cysts in cattle result from excessive growth of the dominant follicle without ovulation and still constitute a major reproductive disorder in this species. One key hormonal characteristic of cows with follicular cysts is the lack of an LH surge, although they have increased plasma estradiol concentrations. Another is a relatively high level of pulsatile secretion of LH that promotes continued growth of the dominant follicle. These LH characteristics seem to result from a functional abnormality in the feedback regulation of LH secretion by estradiol. Treatment with controlled internal drug release devices that increase circulating progesterone levels is effective in resolving follicular cystic conditions by 1) lowering pulsatile LH secretion and 2) restoring the ability of the hypothalamo-pituitary axis to generate an LH surge in response to an increase in circulating estradiol.     

Genetic variability of drought-avoidance root traits in the mini-core germplasm collection of chickpea (Cicer arietinum L.).

Extensive and deep root systems have been recognized as one of the most important traits for improving chickpea (Cicer arietinum L.) productivity under progressively receding soil moisture conditions. However, available information on the range of variation for root traits is still limited. Genetic variability for the root traits was investigated using a cylinder culture system during two consecutive growth seasons in the mini-core germplasm collection of ICRISAT plus several wild relatives of chickpea. The largest genetic variability was observed at 35 days after sowing for root length density (RLD) (heritability, h ² = 0.51 and 0.54) across seasons, and followed by the ratio of plant dry weight to root length density with h ² of 0.37 and 0.50 for first and second season, respectively. The root growth of chickpea wild relatives was relatively poor compared to C. arietinum, except in case of C. reticulatum. An outstanding genotype, ICC 8261, which had the largest RLD and one of the deepest root system, was identified in chickpea mini-core germplasm collection. The accession ICC 4958 which was previously characterized as a source for drought avoidance in chickpea was confirmed as one with the most prolific and deep root system, although many superior accessions were also identified. The chickpea landraces collected from the Mediterranean and the west Asian region showed a significantly larger RLD than those from the south Asian region. In addition, the landraces originating from central Asia (former Soviet Union), characterized by arid agro-climatic conditions, also showed relatively larger RLD. As these regions are under-represented in the chickpea collection, they might be interesting areas for further germplasm exploration to identify new landraces with large RLD. The information on the genetic variability of chickpea root traits provides valuable baseline knowledge for further progress on the selection and breeding for drought avoidance root traits in chickpea.     

In vitro effect of recombinant human granulocyte colony-stimulating factor on canine neutrophil apoptosis

Apoptosis is essential in eliminating neutrophils (polymorphonuclear leukocytes: PMNs) in animals. The suppression of PMN apoptosis is believed to be beneficial in eradicating pathogens and is implicated in the pathogenesis of human inflammatory diseases. In the present study, canine PMNs were stimulated with recombinant human granulocyte colony-stimulating factor (rhG-CSF) to investigate the in vitro effect on the apoptosis of canine PMNs. Apoptotic cell rates were assessed by flow cytometry in relation to the ability of PMNs to produce reactive oxygen species (ROS). Canine PMN apoptosis was markedly suppressed by rhG-CSF treatment, in association with the retention of the PMN ability to produce ROS. The addition of cycloheximide abolished this suppression by rhG-CSF. Moreover, canine PMNs, which were stimulated by rhG-CSF, expressed high levels of anti-apoptotic mcl-1 gene mRNA, as quantified by real-time polymerase chain reaction method. The results suggest that PMNs, stimulated by G-CSF, could work effectively over a longer period to eliminate pathogens, and that the prolongation of the PMN life-span might occasionally aggravate tissue injuries in dogs. In addition, the suppression of PMN apoptosis seems to be mediated by the induction of anti-apoptotic mcl-1 gene expression.     

Detection of fungi producing infection-inhibiting metabolites against <Emphasis Type="Italic">Alternaria alternata</Emphasis> Japanese pear pathotype from fungi inhabiting internal tissues of Japanese pear shoots

Fungi inhabiting Japanese pear were isolated from internal tissues of cv. Nijisseiki, and culture filtrates (CFs) of 100 isolates were evaluated for their inhibitory activity against infection by Alternaria alternata Japanese pear pathotype. CFs of 11 isolates inhibited lesion formation on the pear by the pathogen. Among these isolates, CFs of five isolates inhibited spore germination. CFs of the six other isolates inhibited appressorial formation, infection hypha formation, AK-toxin production, or a combination of these actions. Analysis of sequence homology in the rDNA ITS1 regions of these isolates showed that most isolates had high homology with some fungal endophytes.     

Characterization of Staphylococcus intermedius from pigeons, dogs, foxes, mink, and horses by pulsed-field gel electrophoresis

Staphylococcus intermedius from pigeons, dogs, foxes, mink, and horses, was characterized by pulsed-field gel electrophoresis (PFGE) to evaluate the use of this typing method for discriminating among strains. SmaI cut the chromosomal DNA into 7-13 fragments ranging from approximately 48 kb to 655 kb, with most of the detectable fragments being smaller than 172 kb. S. intermedius from various animals had a high degree of restriction fragment length polymorphism. Pigeon strains have a similar genotype, despite the difference in their isolation area. Phage typing indicated that the dog, fox, and mink strains belong to the canine I or canine II type. The PFGE method further differentiated the mink strains from the dog and fox strains with regard to three fragments between 256 kb and 570 kb. As such, genomic DNA fingerprinting by PFGE appears to be an effective technique for discriminating S. intermedius strains from various animals. A combination of PFGE typing and phage typing would provide more detailed information than the single method for ecological investigations of S. intermedius.     

Intestinal Tritrichomonas suis (=T. foetus) infection in Japanese cats

Tritrichomonas suis (=T. foetus) has recently been reported to be a causative agent of chronic large-bowel diarrhea in cats. While the disease was previously attributed to Pentatrichomonas hominis, the etiologic agent for feline trichomonal diarrhea was identified as T. suis. Although feline trichomonosis due to T. suis has been reported at prevalences ranging from 14 to 31% in Europe and the U.S., no reports of the pathogen have been published to date in Japan. In 2008, however, we encountered a case of feline trichomonosis at the Veterinary Teaching Hospital of Hokkaido University. The parasite was identified as T. suis by nested PCR amplification of partial internal transcribed spacer region 1 and 5.8S ribosomal RNA gene sequences with T. suis-specific primers and DNA sequencing of the amplified products. We then conducted surveys for feline trichomonosis in three different animal hospitals using either cultivation and/or PCR-based assays. The results revealed that 13 of 147 samples (8.8%) were positive for T. suis, and that 5 of the 13 infected cats, which ranged between 1 month and 7.5 years-old, showed chronic diarrhea. Seven of the infected cats were purebred and 6 were mixed breed. These findings suggested that feline trichomonosis is prevalent in Japan, and that T. suis may play a role as a causative agent of feline chronic diarrhea.     

Decreased apoptotic polymorphonuclear leukocyte rate in dogs with pyometra

Polymorphonuclear neutrophil (PMN) apoptosis was examined in three dogs with pyometra by TUNEL assay in a 24-hr incubation period and compared with that in healthy control dogs (n=5). The incidence of apoptotic PMNs in dogs with pyometra was 26.4 +/- 5% and that in healthy dogs was 54.3 +/- 7%. The results indicated that apoptotic PMN rates in dogs with pyometra were significantly lower than those in control dogs (p<0.05), suggesting the prolongation of PMN survival.