Transamination of aminoalkylphosphonic acids with alpha ketoglutarate

Dialyzed homogenates prepared from Escherichia coli, Tetrahymena pyriformis, sea anemone (Anthopleura elegantissima), and mouse liver were tested for ability to transaminate 17 aminoalkylphosphonic acids with alpha-ketoglutarate. 2-Aminoethylphosphonic acid (2-AEP), which occurs naturally in Tetrahymena and anemone, was transaminated by these latter organisms more than any of the substances tested, but not by preparations from liver or E. coli. 3-Aminopropylphosphonic acid was transaminated by all preparations, but much less by Tetrahymena or anemone than was 2-AEP. 2-Amino-3-phosphonopropionic acid was transaminated by all preparations. 2-Amino-4-phosphonobutyric acid was transaminated by three of the preparations, but not by liver. Of the other 13 substances tested, the following gave positive results: DL-1,2-diaminoethylphosphonic acid with E. coli, DL-1,2-diaminoethylphosphonic and aminomethylphosphonic acids with Tetrahymena, DL-1-aminopropylphosphonic acid with anemone, and DL-1-aminoethylphosphonic and DL-1-aminobutylphosphonic acids with liver. The significance of these transaminations is discussed.     

Mechanism of manganese toxictty and tolerance of plants VII. effect of light intensity on manganese‐induced chlorosis

Effect of light intensity on Mn‐induced chlorosiss was investigated with bush bean (Phaseolus vulgaris L.) and corn (Zea mays L.) seedlings. The seedlings were grown in nutrient solutions containing different concentrations of Mn in enclosures which transmitted different percentages of the total solar radiation. At high levels of Mn in nutrient solution, the increase in light intensity increased the Mn uptake by the plant and resulted in a decrease in the chlorophyll content of the leaves. Even at similar levels of Mn concentrations within the leaves, high light intensity increased the severity of Mn‐induced chlorosis.

Photobleaching experiments were carried out with isolated chloroplasts suspended in media containing 0, 10^‐4 , 10^‐3,10^‐2 and 10^‐1 M Mn²⁺. Addition of Mn²⁺ to the medium decreased the extent of photobleacing of chlorophyll with increaing Mn²⁺ concentration up to 10^‐3 M . In concentrations of Mn²⁺ higher than 10^‐3 M, the extent of bleaching was increased again, accompanied by precipitation of oxidized manganese in the medium.

It is suggested that high light intensity stimulates not only the Mn uptake by the plant but also the destruction of chlorophyll when Mn in excess.     

Comparison of PCR assays for detection and quantification of Phomopsis sclerotioides in plant and soil

We developed a real-time PCR assay using a TaqMan probe (TM-qPCR) for specific detection and quantification of Phomopsis sclerotioides, causal agent of black root rot of cucurbit crops. The design of the primer sets and hybridization probe was based on the internal transcribed spacer region of the ribosomal DNA. The TM-qPCR assay was compared with a conventional, standard PCR (sPCR) assay and on a quantitative real-time PCR (SG-qPCR) assay based on SYBR Green I. The TM-qPCR assay had a detection limit of ca. 0.4 fg of P. sclerotioides DNA, which was approximately 100 times more sensitive than the sPCR assay and almost equivalent to the SG-qPCR assay. The TM-qPCR and SG-qPCR assays both were able to detect various quantities of P. sclerotioides DNA from diseased plants and infested soils, including DNA levels that were not detectable by the sPCR assay. However, the TM-qPCR was advantageous for samples containing PCR-inhibiting substances because its multiplex real-time PCR function allows the adjustment of cycle threshold values with an internal control. Based on the high specificity and sensitivity required for analyzing DNA in natural samples, the newly developed TM-qPCR assay was the most reliable tool for rapidly detecting and quantifying P. sclerotioides in plant and soil samples.     

Induction of Apoptotic Cell Death in Human Leukemia U937 Cells by C18 Hydroxy Unsaturated Fatty Acid Isolated from Red Alga Tricleocarpa jejuensis

Our previous studies have found that (±)-(E)-12-hydroxyoctadec-10-enoic acid (HOEA) isolated from the red alga Tricleocarpa jejuensis showed cytotoxic effects on various living organisms including harmful microalgae, Gram-positive bacteria, and mammalian tumor cells. Since natural products with apoptosis-inducing ability can be promising anti-cancer agents, in this study, we investigated the cytotoxic mechanism of HOEA on U937 cells focusing on apoptosis induction. HOEA showed much stronger cytotoxic and cytolytic effects on U937 cells than elaidic acid, which has similar structure but no 12-hydroxy group, suggesting that hydroxy group is important for the cytotoxicity of HOEA. HOEA induced apoptotic nuclear morphological changes, DNA fragmentation, and decrease in mitochondrial membrane potential. Furthermore, time-dependent increase in annexin V+/PI+ cell population in HOEA-treated U937 cells was detected. Among the apoptosis-related reagents, caspase-family inhibitor almost completely inhibited HOEA-induced DNA fragmentation. In the analyses using specific caspase-substrates, extremely high cleavage activity toward caspase-3/7/8 substrate was observed in HOEA-treated U937 cells, and weak activities of caspase-1 and -3 were detected. Analyses using specific caspase inhibitors suggested that caspase-3 and caspase-8 might be predominantly responsible for the cleavage activity. Activation of these caspases were also confirmed by western blotting in which significant levels of cleaved forms of caspase 3, caspase 8, and PARP were detected in HOEA-treated U937 cells. Our results suggest that HOEA is capable of inducing apoptosis in U937 cells in which caspase-3 and caspase-8 might play important roles. Since the cytotoxic effect of HOEA is not strictly specific to tumor cells, development of appropriate drug delivery system for selective tumor targeting is necessary for the clinical applications to reduce the possible side effects.     

Phenotypic changes in reproductive traits with changes in stock size of the starspotted smooth-hound Mustelus manazo in Tokyo Bay, Japan

Reproductive traits are among the primary determinants of population dynamics, and their changes could affect stock size. We investigated differences in reproductive traits of the starspotted smooth-hound Mustelus manazo in Tokyo Bay between the 1990s (a low-stock period) and the 2000s (a high-stock period). Peak timings of mating (May–July), ovulation (May–June), and parturition (May–June) were similar between the two periods. However, the size at first maturity in the 2000s was smaller than that in the 1990s for both sexes. In addition, embryo-related parameters differed greatly between the two periods. Slopes of size–fecundity regression in the 2000s decreased to 43–73 % of the 1990–1996 values, suggesting a substantial decline in fecundity during the 2000s. Frequency distribution of the maximum ovum diameter during the ovulation season showed two distinct two modes in 1990s while it showed a substantial dispersion during the 2000s, implying that changes occurred in the developmental pattern of ova in the ovary. Undeveloped eggs were present in the uteri with low frequency from September to May during the 2000s, but they were totally absent from September through May in the 1990s. The increased number of remnant undeveloped eggs that did not become embryos may explain the fecundity decline during the 2000s.     

Ammonia Emission from a Young Larch Ecosystem Afforested after Clear-Cutting of a Pristine Forest in Northernmost Japan

The present study aimed to elucidate the atmosphere–forest exchange of ammoniacal nitrogen (NH_X-N) at a young larch ecosystem. NH_X-N exchanges were measured at a remote site in northernmost Japan where 4-year-old larches were growing after a pristine forest had been clear-cut and subsequent dense dwarf bamboo (Sasa) had been strip-cut. The site was a clean area for atmospheric ammonia with mean concentrations of 0.38 and 0.11 μg N m^?3 in snowless and snow seasons, respectively. However, there was a general net emission of NH_X-N. The annual estimated emission of NH_X-N of 4.8 kg N ha^?1 year^?1 exceeded the annual wet deposition of 2.4 kg N ha^?1 year^?1, but the weekly exchange fluxes may have been underestimated by 28–60%. The main cause of the ammonia loss from the young larch ecosystem was probably enhanced nitrogen supply stimulated by the cutting of the pristine forest and Sasa, in particular, the Sasa.     

Flowering behaviors of the inflorescences of an alien plant (Plantago asiatica), an alpine plant (Plantago hakusanensis), and their hybrids on Mt. Hakusan,Japan

In the subalpine zone on Mt. Hakusan, Japan, Plantago asiatica, an alien plant, and Plantago hakusanensis, a native alpine species, grow sympatrically along with their putative hybrids. Here, their flowering behavior, which affects the frequency of hybridization and the colonizing ability of P. asiatica and its hybrids, is described. The flowering behavior of each species and of two F₁ hybrids from different seed parents was determined based on the position of the flower in the inflorescence by using a generalized linear mixed model. The percentage fruit set of individually bagged inflorescences was calculated to corroborate the assumptions of the opportunities for self‐pollination. All the flowers were protogynous; however, many P. asiatica anthers dehisced before browning of the stigma in the flower and the sex presentations in the inflorescence were asynchronous. The percentage of fruit set was high. Consequently, P. asiatica has the opportunity for self‐pollination within the flower and in the inflorescence. In contrast, the P. hakusanensis anthers dehisced after browning of the stigma in the flower; their sex presentation was synchronous in the inflorescence, showing negligible opportunities for self‐pollination, and the fruit set was low. Accordingly, in the field, P. hakusanensis might require pollination among the inflorescences for seed production and be actively outcrossed, while P. asiatica is able to outcross in the early flowering phase. Therefore, P. asiatica and P. hakusanensis have opportunities for hybridization. The F₁ hybrids exhibited intermediate flowering behavior and produced fruits, demonstrating the potential to reproduce by selfing.     

Antiangiogenic activity of brown algae fucoxanthin and its deacetylated product, fucoxanthinol

The antiangiogenic effects of fucoxanthin and a deacetylated product, fucoxanthinol, were examined. Fucoxanthin significantly suppressed HUVEC proliferation and tube formation at more than 10 microM, but it had no significant effect on HUVEC chemotaxis. The formation of blood vessel-like structures from CD31-positive cells was evaluated using embryonic stem cell-derived embryoid bodies. Fucoxanthin effectively suppressed the development of these structures at 10-20 microM, suggesting that it could suppress differentiation of endothelial progenitor cells into endothelial cells involving new blood vessel formation. Fucoxanthin and fucoxanthinol suppressed microvessel outgrowth in an ex vivo angiogenesis assay using a rat aortic ring, in a dose-dependent manner. These results imply that fucoxanthin having antiangiogenic activity might be useful in preventing angiogenesis-related diseases.     

柚木黑色条纹心材的颜色和化学特性

印尼岛的柚木心材在年轮周围显示了不规则的黑色条纹变化。本研究调查柚木黑色条纹心材的颜色和化学特性。利用色坐标（CIELAB）测定颜色特性（pH值、无机物含量、抽出物含量和特性）。结果表明：黑色条纹的颜色较对照少12-15个亮度单位。因此,黑色条纹的颜色与对照比较,有较多的红色,较少的黄色、色彩和色度。黑色条纹心材部分的pH值灰度含量和钙含量都比对照的高。黑色条纹的心材抽出物含量较对照的高。推测当生物活性物质（杀虫剂）明显增加时,心材显示发黑的过程可能是一种防御机制。