浑善达克沙地牧户经营与草地变化的实证分析

本文以浑善达克沙地牧户调查数据为基础,在草地畜牧业可持续发展理论指导下,通过对牧户经营现状以及草地变化状况的实证分析,明确了牧户经营基本特点、经营收入支出构成与草地资源变化特征,并提出调整畜种结构,适当增加牛的饲养比重;科学管理,提高牲畜出栏率;加强牲畜改良,提高良种比率;完善草畜平衡制度,加强监督、执法力度等对策。     

A possible function of Nik-related kinase in the labyrinth layer of delayed delivery mouse placentas

In mice and humans, Nik-related protein kinase (Nrk) is an X-linked gene that encodes a serine/threonine kinase belonging to GCK group 4. Nrk knockout (Nrk KO) mice exhibit delayed delivery, possibly due to defective communication between the Nrk KO conceptus and its mother. However, the mechanism of delayed labor remains largely unknown. Here, we found that in pregnant mothers with the Nrk KO conceptus, the serum progesterone (P4) and placental lactogen (PL-2) concentrations in late pregnancy were higher than those in the wild type. Moreover, we demonstrated that Nrk is expressed in trophoblast giant cells (TGCs) and syncytiotrophoblast-2 (SynT-2) in the labyrinth layer of the mouse placenta. In the human placenta, NRK is also expressed in Syn-T in villi. Both human Syn-T and mouse TGCs of the labyrinth layer are present within fetal tissues that are in direct contact with the maternal blood. The labyrinth layer of the Nrk KO conceptus was gigantic, with enlarged cytoplasm and Golgi bodies in the TGCs. To investigate the function of Nrk in the labyrinth layer, a differentially expressed gene (DEG) analysis was performed. The DEG analysis revealed that labor-promoting factors, such as prostaglandins, were decreased, and pregnancy-maintaining factors, such as the prolactin family and P4 receptor, were increased. These findings suggest that the Nrk KO mice exhibit delayed delivery owing to high P4 concentrations caused by the hypersecretion of pregnancy-maintaining factors, such as PL-2, from the placenta.     

Seroconversion of anti-Getah virus antibody among Japanese native Noma horses around 2012

Getah virus (GETV), an arthropod-borne virus transmitted by mosquitoes, has been isolated from several animals. GETV infection in horses shows clinical signs such as fever, rash, and edema in the leg. Noma horses are one of the eight Japanese native horses. The present study aimed to clarify the occurrence of GETV infection in Noma horses. Serum samples collected from Noma horses were analyzed using a virus neutralization test and enzyme-linked immunosorbent assay and showed that the anti-GETV antibody titers in the samples collected in 2017 were significantly higher than those collected in 2012. We concluded that a seroconversion of anti-GETV antibodies was occurred in the Noma horse population around 2012, providing evidence of the GETV epidemic in Japan circa 2012.     

Embryo and fetal position during pregnancy by ultrasonographic examinations in bottlenose dolphin (Tursiops truncatus)

From 2012 to 2017, serial ultrasonographic evaluation of 5 healthy bottlenose dolphins, Tursiops truncatus, were performed over the course of 6 pregnancies in Enoshima Aquarium. A total of 98 ultrasonographic examinations were included in the study. In three out of six cases, two embryos were observed between umbilicus and genital slit, and side of umbilicus in the dam’s body. All embryos were located in right below the peritoneum and observed from 308 to 325 days pre-partum. These days were corresponding to from 58 to 61 days after copulation respectively. The diameter of the embryo sac was approximately 4 cm. In three cases, the fetal head was located in the dam’s left lateral between umbilicus and genital slit from approximately 90 days pre-partum to the parturition. A snout of fetus is at the top of the uterine horn, and the tail lies close to the cervix. All six calves were fluke-first births (breech presentation). It was conjectured that the contraction of the dam’s uterus during parturition forced the fetus to invert, and the fetal tail fluke was expelled from the dam’s body. In three cases, judging from orientation of fetal tail fluke faced towards left side of the dam, a fetal position might be RSL (Right Sacrum-Lateral) within the birth canal. In the other three cases, the left and right positions of the fetus and the dam’s body are reversed during pregnancy and parturition.     

Flagellin glycosylation is ubiquitous in a broad range of phytopathogenic bacteria

Glycosylation of flagellin is known to be involved in filament stabilization, motility, and virulence in Pseudomonas syringae. Here we investigated flagellin glycosylation in other phytopathogenic bacteria. Analyses of deduced amino acid sequences, glycostaining, and molecular masses of purified flagellins revealed that flagellins from all phytopathogenic bacteria investigated were glycosylated. Furthermore, the flagellin in a glycosylation-defective mutant of Xanthomonas campestris pv. campestris (Xcc) had a reduced molecular mass, and motility and virulence of the mutant toward host leaves decreased. These results suggest that flagellin glycosylation is ubiquitous in most phytopathogenic bacteria and that flagellin glycosylation is required for virulence in Xcc.     

Specific detection of potentially allergenic peach and apple in foods using polymerase chain reaction

Two PCR methods were developed for specific detection of the trnS-trnG intergenic spacer region of Prunus persica (peach) and the internal transcribed spacer region of Malus domestica (apple). The peach PCR amplified a target-size product from the DNA of 6 P. persica cultivars including 2 nectarine and 1 flat peach cultivar, but not from those of 36 nontarget species including 6 Prunus and 5 other Rosaceae species. The apple PCR amplified a target-size product from the DNA of 5 M. domestica cultivars, but not from those of 41 nontarget species including 7 Maloideae and 9 other Rosaceae species. Both methods detected the target DNA from strawberry jam and cookies spiked with peach and apple at a level equivalent to about 10 μg of total soluble proteins of peach or apple per gram of incurred food. The specificity and sensitivity were considered to be sufficient for the detection of trace amounts of peach or apple contamination in processed foods.     

Occurrence of glucosamine in higher plants

Occurrence of the unknown basic ninhydrin positive substance in young plant tissue supplied with a high level of ammonium nitrogen has been reported in the previous paper (1). This substance disappeared when the supply of ammonium nitrogen was stopped or the source of nitrogen was changed from ammonium nitrogen to nitrace nitrogen, and this substance was verg scarcely detected when the level of ammonium nitrogen in culture solution was as low as 3 ppm or the foren of nitrogen source was nitrace nitrogen. It is very interesting to identify this substance, as the occurrence of this substance is a distinctive character of the plant which han been supplied with a higher level of ammonium nitrogen and has developed the symptoms of ammonia toxicity.     

Responses to aluminium of suspension-cultured tobacco cells in a simple calcium solution

In a simple solution containing 3 mM CaCl₂ and 3% sucrose (pH 4.5), tobacco cells (Nicotiana tabacum L.) at the logarithmic phase of growth remained viable at least for 24 h. In this medium, the toxic effect of aluminium (Al) on the plasma membrane was investigated for up to 24 h. After the addition of Al to the cell suspension, Al started to accumulate immediately in the cells, and a maximum value was observed at 9 h. Al induced callose deposition, but did not enhance significantly the uptake of Evans blue (a nonpermeating dye), the per oxidation of lipids and the leakage of potassium (K) ions. Furthermore, the AI-treated cells were stained with fluorescein diacetate (FDA) as much as untreated control cells. These results suggest that the accumulation of Al does not damage the membrane. The addition of Fe(II) to the cells which had been exposed to Al for 12 h resulted in immediate lipid peroxidation and Evans blue uptake several hours later. A combination of Al and Fe(II) caused the K leakage, and enhanced the deposition of callose more than Al alone. These results suggest that the accumulation of Al sensitizes the membrane to the Fe(II)-mediated peroxidation of lipids, and that the Al-enhanced per oxidation of lipids is a direct cause of the loss of integrity of the plasma membrane (or cell death) in the Ca medium.     

Uptake of 15 trace elements in arbuscular mycorrhizal marigold: Measured by the multitracer technique

The effect of arbuscular mycorrhizal (AM) colonization on the uptake of trace elements in marigold (Tagetes patula L.) was studied using a multitracer consisting of radionuclides of ⁷Be, ²²Na, ⁴⁶Sc, ⁵¹Cr, ⁵⁴Mn, ⁵⁹Fe, ⁵⁶Co, ⁶⁵Zn, ⁷⁴As, ⁷⁵Se, ⁸³Rb, ⁸⁵Sr, ⁸⁸Y, ⁸⁸Zr, and ^95mTc. Marigold plants were grown under controlled environmental conditions in sand culture either without mycorrhizas or in association with an AM fungus, Glomus etunicatum. The multitracer was applied to the pot, and plants were harvested at 7 and 21 d after tracer application. We found that the uptake of ⁷Be, ²²Na, ⁵¹Cr, ⁵⁹Fe, ⁶⁵Zn, and ^95mTc was higher in the mycorrhizal marigolds than in the non-mycorrhizal ones, while that of ⁴⁶Sc, ⁵⁶Co, ⁸³Rb, and ⁸⁵Sr was lower in the mycorrhizal marigolds than in the non-mycorrhizal ones. Thus, the multitracer technique enabled to analyze the uptake of various elements by plant simultaneously. It is suggested that this technique could be used to analyze the effects of AM colonization on the uptake of trace elements by plant.     

Response of determinate- and semi-determinate-types of common bean to elevated CO2 concentration in the atmosphere

The growth of determinate-type and semi-determinate -type plants of common beam (Phaseolus vulgaris L.) was studied at elevated (700 μL L^-1) and ambient (350 μL L^p-1) CO, concentrations in an open-top chamber. Successive changes in dry matter production and in the number of stems and branches were investigated. To evaluate the sink-source balance at different CO₂ concentrations, ¹³CO₂ was introduced to the leaves during the pod filling stage and the ¹³C distribution profile was analyzed. In the elevated CO₂ treatment, no significant differences in dry matter production were observed for the determinate -type plants, unlike in the semi-determinate-type ones, where the volume was 1.3 times bigger than those in the ambient CO₂ treatment. This enhanced growth in the semi-determinatetype plants mainly involved the branches. Starch accumulation in leaves at elevated CO₂ concentratton was up to 200 and 300 mg glucose g DML^-1 for determinate- and semi-determinate-types, respectively. Though the increased accumulation of starch under elevated CO₂ treatment was more pronounced in the semi-determinate-type plants, it appeared that photosynthesis was not down-regulated. The net assimilation rate of the semi-determinate-type plants in the elevated CO₂ treatment was generally higher than that in the ambient CO₂ treatment. The semi-determinate-type plants could take advantage of the elevated CO₂ treatment for the distribution of photosynthates to branches, while in the determinate-type plants the growth of the branches could not be expanded, and consequently plant growth was not enhanced by elevated CO₂ treatment.