鹿角海萝的繁殖生物学及室内培养的研究

在鹿角海萝Gloiopeltis tenax藻体生育期内,观察了大连沿海鹿角海萝的自然生态及藻体生长过程;在繁殖期内定期采集种藻进行孢子放散,测定了藻体生长、孢子放散量与水温的关系;使用培养皿、贝壳等附着基采集四分孢子和果孢子并在室内进行培养。结果表明：1）鹿角海萝在大连沿海的生育期为10月至翌年7月,藻体在4月下旬至5月上旬生长最快,此阶段水温为6～9℃。2）鹿角海萝的繁殖期为4月下旬至6月下旬（水温6～12℃）,其中果孢子体在4月下旬至5月中旬（水温6～10℃）放散,放散高峰为5月上旬,最高放散量为0．9×10^6个／g;5月上旬至6月下旬（水温9～12℃）四分孢子体开始放散,高峰期为6月上旬,最高放散量为1．65×10^6个／g。3）四分孢子和果孢子附着后均可萌发形成盘状体,盘状体直径达250um左右时形成直立枝,盘状体和直立枝在每天上午和下午各干露2h条件下,生长速度明显快于对照组,直立枝经在室内培养成为鹿角海萝幼苗。     

Discovery and structure optimization of a novel corn herbicide,tolpyralate

Tolpyralate, a new selective postemergence herbicide developed for the weed control in corn, possesses a unique chemical structure with a 1-alkoxyethyl methyl carbonate group on the N-ethyl pyrazole moiety. This compound shows high herbicidal activity against many weed species, including glyphosate-resistant Amaranthus tuberculatus. Tolpyralate targets 4-hydroxyphenylpyruvate dioxygenase (4-HPPD), which is involved in the tyrosine degradation pathway. Inhibition of the enzyme destroys the chlorophyll, thereby killing the susceptible weeds. Details of tolpyralate discovery, structure optimization, and biological activities are described.     

Effects of beer and hop on ionotropic gamma-aminobutyric acid receptors

Beer induced the response of the ionotropic gamma-aminobutyric acid receptors (GABA(A) receptors) expressed in Xenopus oocytes, indicating the presence of gamma-aminobutyric acid (GABA)-like activity. Furthermore, the pentane extract of the beer, hop (Humulus lupulus L.) oil, and myrcenol potentiated the GABA(A) receptor response elicited by GABA. The GABA(A) receptor responses were also potentiated by the addition of aliphatic esters, most of which are reported to be present in beer flavor. Aliphatic esters showed the tendency to decrease in the potentiation of the GABA(A) receptor response with an increase in their carbon chain length. When myrcenol was injected to mice prior to intraperitoneal administration of pentobarbital, the pentobarbital-induced sleeping time of mice increased additionally. Therefore, the beer contained not only GABA-like activity but also the modulator(s) of the GABA(A) receptor response.     

Hydrogeochemical Conditions Affecting Acidification of Stream Water in Mountainous Watersheds

Acid deposition in eastern Asia will increase and freshwaters in Japan are likely to become acidified in future. In order to make long-term predictions about freshwater acidification, it is necessary to evaluate acid neutralization mechanisms in Japanese watersheds. Ikeda and Miyanaga (1999) earlier proposed a method of separating acid-neutralization capacity into chemical weathering and cation exchange. By this means, we were able to assess the effect of hydrogeochemical properties on chemical weathering and stream water chemistry for three watersheds in Japan. On the basis of this assessment, acid-neutralization stream water chemistry was predicted using the ILWAS (Integrated Lake-Watershed Acidification Study) model. The main factors determining acidification are the thickness of weatherd profile and chemical weathering rates. The principal results are: (1) for non-acidified watersheds in Japan, acid deposition is neutralized by chemical weathering of primary minerals; (2) freshwaters in Japanese watersheds will not acidify even if acid deposition increases to the extent found in an acidified watershed in the U.S.A.     

Generation of mouse induced pluripotent stem cells without viral vectors

Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by introducing Oct3/4 and Sox2 with either Klf4 and c-Myc or Nanog and Lin28 using retroviruses or lentiviruses. Patient-specific iPS cells could be useful in drug discovery and regenerative medicine. However, viral integration into the host genome increases the risk of tumorigenicity. Here, we report the generation of mouse iPS cells without viral vectors. Repeated transfection of two expression plasmids, one containing the complementary DNAs (cDNAs) of Oct3/4, Sox2, and Klf4 and the other containing the c-Myc cDNA, into mouse embryonic fibroblasts resulted in iPS cells without evidence of plasmid integration, which produced teratomas when transplanted into mice and contributed to adult chimeras. The production of virus-free iPS cells, albeit from embryonic fibroblasts, addresses a critical safety concern for potential use of iPS cells in regenerative medicine.     

Association of an SNP marker in exon 24 of a class 3 phosphoinositide‐3‐kinase (PIK3C3) gene with production traits in Duroc pigs

A C?T single nucleotide polymorphism (SNP) on exon 24 of the porcine class 3 phosphoinositide‐3‐kinase (PIK3C3) gene is considered a possible genetic marker for selecting backfat (BF) thickness and carcass fat, although only one study has published results on its effects by performing experiments on a single resource family. We analyzed the association of this PIK3C3 polymorphism with production traits in 739 Duroc pigs. The C allele frequency was 67.9% in our study population. PIK3C3 polymorphism showed significant effects on average daily weight gain (ADG), BF thickness, intermuscular fat content (IMF), and the size of the loin eye muscle area (EMA). The C alleles increased ADG, BF and IMF, and decreased EMA. The predicted differences in traits between the homozygous pigs of the C and T alleles were 40 g/day for DG, 1.2 mm for BF, 0.44% for IMF, and 1.6 cm² for EMA. Furthermore, the statistical models for estimating the breeding values of each trait had lower Akaike's information criterion values when adding PIK3C3 genotype information. We therefore confirmed that the polymorphism in PIK3C3 (C2604T) has the potential to be a genetic marker for production traits in Duroc pigs.     

Evaluation of wood-based panel durability using bending properties after accelerated aging treatments

The durability of wood-based panels was evaluated by comparing the bending properties of panels subjected to five accelerated aging treatments with the bending properties of panels that had experienced 5 years of outdoor exposure in Shizuoka City, Japan. In each accelerated aging treatment, methylene diphenyl diisocyanate-bonded panels showed higher bending retention than phenol formaldehyde (PF)-bonded panels. The bending retentions after six repeated cycles of the JIS-B, APA D-1, and ASTM treatments showed a correspondence of nearly one-to-one in the data for the three different treatments. The Shizuoka City 5-year outdoor exposure test data showed that the bending retentions of all panels decreased with time. In particular, the bending retentions of PF resin-bonded particleboard and oriented strandboard made from aspen were less than 30% and 10% of the original values, respectively, after the 5-year exposure period. The deterioration of the bending properties after the 5-year outdoor exposure in Shizuoka City was the same as that for six repetitions of the ASTM treatment.     

Deep ultraviolet light-emitting hexagonal boron nitride synthesized at atmospheric pressure

Materials emitting light in the deep ultraviolet region around 200 nanometers are essential in a wide-range of applications, such as information storage technology, environmental protection, and medical treatment. Hexagonal boron nitride (hBN), which was recently found to be a promising deep ultraviolet light emitter, has traditionally been synthesized under high pressure and at high temperature. We successfully synthesized high-purity hBN crystals at atmospheric pressure by using a nickel-molybdenum solvent. The obtained hBN crystals emitted intense 215-nanometer luminescence at room temperature. This study demonstrates an easier way to grow high-quality hBN crystals, through their liquid-phase deposition on a substrate at atmospheric pressure.     

Small-Scale Preparation of Fluorescently Labeled Chemical Probes from Marine Cyclic Peptides,Kapakahines A and F

A number of bioactive marine natural products have been isolated so far, but it is still difficult to disclose their modes of action. In this study, we prepared fluorescently labeled chemical probes from the cytotoxic marine cyclic peptides kapakahines A (1) and F (2) to visualize their localization as the first step of the study of their modes of action. We used fluorescent dyes 3a or 3a/b (a 1:1 mixture of 3a and 3b) whose terminal N-hydroxysuccinimide (NHS) group can react with the free amino groups of kapakahines. The fluorescently labeled kapakahine A (Kap A-5-FL, 5a) stained P388 murine leukemia cells and HeLa human cervical cancer cells, while cells treated with fluorescently labeled kapakahine F (Kap F-5-FL, 6a) only weakly stained them. Further analysis of the confocal images of the stained cells with higher magnification (×100) indicated the localization of Kap A-5-FL (5a) in the cells. In this paper, we report the small-scale preparation and a new delivery method of fluorescent probes, as well as the application of these procedures to cell staining.     

Investigations on the water economy of volcanic ash soils

To elucidate the influence of climate and vegetation upon the vertical distribution of soil moisture and its seasonal change is one of the fundamental problems in the studies on water economy of volcanic ash soils, that cover the larger parts of Japan, and have characteristic soil-water system.¹⁾ Few data are now available in this field, despite the fact that management of volcanic ash soils is practically one of the most urgent problems in Japan.