Effects of bisphenol A (BPA) on placentation and survival of the neonates in mice

The effects of bisphenol A (BPA) on placentation have not been fully determined. The aim of this study was to clarify the structural changes of the placenta, abortion rate, and survival of neonates after BPA administration in mice. BPA (10 mg/kg/day) was administered to pregnant mice (BPA mice) subcutaneously from the first day of pregnancy (Day 0) to Day 7 (8 days total). The number of embryos and weights of whole uteri were measured on Days 10 and 12. Morphological changes in the placentae were examined by light microscopy on the corresponding days of pregnancy. The number of neonates was also counted. Survival rates were periodically calculated for neonates from the first day after parturition (P-Day 0) to P-Day 56. The number of embryos and weight of the uterus on Days 10 and 12 were significantly decreased by BPA injection. No notable differences were recognized between the left and right uteri. The proportion of the labyrinthine zone per whole placenta in the BPA mice became lower than that in the controls, and that of the metrial gland was higher in the BPA mice. The intervillous spaces of the placenta were narrower in the BPA mice. Degenerative changes were found in the trophoblastic giant cells and spongiotrophoblast layers of the BPA mice. The number of BPA mouse neonates was drastically decreased within 3 days after birth, and no mice survived after P-Day 56. The results suggest that BPA not only disrupts placental functions and leads to abortion through chronic stimulation of gene expression by binding to DNA but that it also affects the mortality of neonates through indirect exposure of embryos.     

利用ISSR标记进行菜用大豆和普通大豆的分类

ISSR标记技术因具有很高的多肽性而被广泛应用于遗传多样性研究.进行菜用大豆品种多样性研究将有助于育种家进行杂交亲本的合理选配.采用ISSR标记技术对37个菜用大豆品种(系)和13个普通大豆品种(系)进行了分类研究.结果表明:50个ISSR引物中有11个引物没有多肽性,其他39个引物共产生132条谱带,其中81条多肽性谱带,占61.4%.引物扩增的谱带数在l～7条之间,大小为830～3530 bp.每个引物平均扩增的谱带数和多肽性带数分别为3.3和2.1.聚类分析结果表明,可将供试的50个品种划分为3个类组,扁茎大豆Taikadai-zu单独一组,7个普通大豆(多数为中国选育)划归为B组,C组由日本菜用大豆和4个普通大豆组成.C组还可以划分成若干亚组,同一亚组的品种具有相似的性状,比如有一亚组的品种均是褐脐、茶色种皮、白花、不易炸荚.系选的品种和原始品种在分类图中也显示出其密切的亲缘关系.基于ISSR标记的分类可以反映菜用大豆的遗传关系,菜用大豆和普通大豆之间存在遗传多样性,合理保存菜用大豆种质将有助于未来大豆品质改良计划.     

Morphology of placentome in Korean water deer Hydropotes inermis argropus

The placenta of the Korean water deer was anatomically examined to accumulate basic information regarding its reproductive system. The convex placentomes with five to nine well-developed pedicles were observed in the whole uterine horns, and therefore, the placenta was classified as oligocotyledonary. The evidence indicating the migration of binucleate cells (BNCs) from trophectoderm to the uterine epithelium led to the histological classification of the placenta as synepitheliochorial. The number of fetuses was markedly higher than that in other ruminant species. However, the number of placentomes was found to be similar to the other Cervidae species. Therefore, these results suggest that the Korean water deer may possess special mechanisms or structures at the fetus attachment site to maintain this unusally high number of fetuses.     

Effect of removal of free oxides on changes in dispersibility and charge characteristics of soils

Changes in dispersibility and charge characteristics of two soils with different colloidal properties were investigated after various extracting treatments of free oxides. The soil samples were taken from the upland field in a reclaimed area (highly dispersive) and from the B horizon of an adjacent forest area (physically stable), both of which derived from the same parent material. Special attention was paid to selective extraction of Al and Fe oxides. After the extraction of free oxides by conventional methods such as DCB or oxalate treatment, dispersibility of the soils which always became too high made it difficult to relate the amounts of removed oxides with the changes in dispersibility. Thus, extractions by milder treatments were designed in order to remove varying amounts of free oxides using several organic salt solutions. Among the treatments, citrate and oxalate extracted more Al oxides, followed by tartrate. Dithionite, acetate, and NaCl extracted only trace amounts of Al oxides. This order seemed to be controlled by the stability constants of organo-Al complexes. The changes in dispersibility of the residual soil were related to the amount of extracted Al, especially for the forest soil, but not to Fe or Si. After these treatments, the amount of positive charges of the soil decreased while that of negative charges increased. For instance, the amount of total charges of the forest soil after DCB treatment was 1.5 times larger than that of the non-treated soil at the dispersion pH, which was mainly attributed to the removal of Al oxides. Although the amount of removed Al oxides was relatively small, the changes in dispersibility of the residual forest soil were drastic, indicating that free oxides (mainly Al) removed by milder treatments were the most external, active fractions. This interpretation suggests the practical importance of the release of amorphous sesquioxides in the natural weathering process in preventing the dispersion of potentially dispersive soils.     

Formation of Methyl Mercaptan in Paddy Soils (II)

In the previous paper₁₎, the authors proposed a method for determining methyl mercaptan formed in paddy soils. In this method, methyl mercaptan was expelled by nitrogen gas from Paddy soils, and was introduced into 4% mercuric CYanide solution after separation from hydrogen sulfide by hydrous calcium chloride and lead acetate (solid). The methyl mercaptan caught by mercuric cyanide solution was measured by colorimetric method using dimethyl-p-phenylenediamine and ferric chloride solutions. And then, the analysis of several field soils was conducted by using this method.     

Vermiculite-Type Clay Minerals in Some “Kuroboku” Soils Distributed in Mie Prefecture of West Japan

In the past several years, the occurrence of vermiculite-type clay minerals and the problem of the formation of Al-interlayers have attracted the intensive attention of soil clay mineralogists. A number of papers have appeared in Japan, in Which the identification data of the vermiculite-type minerals with stable 14 Å spacing were given. (Matsui 1959, 1960; Kanno 1961b, Kato 1961, 1962a, 1962b; Egawa 1963).     

Studies on The Mechanism of Root Damage of Rice Plants in The Peat Paddy Field (Part 2)

In the previous paper (1), it was assumed chat some inhibitory soil substances in submergel peaty soil, such as ferrous iron, sulfide, organic acids, and unknown minor organic substances like humus subordinaten might have contributed to root damage. This assumption is draven from the results of the soil leachate experiments. Two other subjects to be investigated for full understanding of the mechanistu of root damageare are:     

Clay mineral composition of some volcanogenous soils in Indonesia and the Philippines

Clay fractions of three Andosols and a Latosol occurring in Indonesia, and two Alluvial Soils derived from pyroclastic sediments in the Philippines were examined by means of chemical analyses, X-ray diffraction, differential thermal analysis, thermogravimetry, infrared absorption spectroscopy, and electron microscopy. The results are summarized as follows.

Allophane is a dominant clay mineral of young volcanogenous soils occurring in the tropics. Small amounts of halloysite, gibbsite, and imogolite are also found in some of the young volcanogenous soils. Halloysite and imogolite are relatively abundant in the surface soil, while gibbsite is more abundant in the subsoil. In the clay fraction of the young volcanogenous soils in the tropics, α-cristobalite is often present, but quartz occurs rarely. Small amounts of feldspars are also present in the Philippine soils. 2 : 1-type minerals are found to a small extent in some of the sample soils. The above results agree well with the results for Japanese Andosols, except for a difference in the primary mineral composition.     

The infrared absorption band of allophane near 1,650 cm-1

In the infrared absorption (IR) spectrum of the water in allophane, two kind of the absorption band within on region is found near 3,450 and 1,650cm^-1 associated with O-H stretching vibration and O-H deformation vibration, respectively. The maximum of IR band associated with stretching vibration in allophane specimens dried under the relative humidity of 30% at the room temperature, was situated at 3,467 cm^-1 for the Misotsuchi and at 3,461 cm^-1 for the Kanumatsuchi (4). The band was shifted to higher wave-number as heating the specimen till 300°C (4). In this note, the situation of IR band associated with O-H deformation vibration of the water adsorbed on allophanes was exactly measured, because it was hardly done in the past.     

Nitrogen fixation in paddy soils

The 4 long-term experimental plots (Umbric haplaquept) with different fertilizer treatment at Cent. Agric. Exp. Sta. in Konosu City, Saitama Prefecture, were used for the sites of investigation. The 4 plots were NF (applied with no fertilizer), IF (applied with inorganic fertilizers), GM (applied with green manure and CaCO₂), and OM (applied with manure and inorganic fertilizers). Flooded water, floating weed, upper (0-2cm) and lower (2-10cm) parts of Apg horizon and rhizosphere were collected from each plot before flooding, during flooding, and after drainage. These samples were analyzed for N₂-fixing activity by acetylene reduction method, pH, Eh, and contents of Fe²⁺, NH₄ ⁺, chlorophyll-type compounds, and water-soluble carbohydrates.

The N₂-fixing activity of all samples showed almost the same pattern of change with time: very low before flooding, rapidly increased after flooding, the maximum value at the maximum tillering stage of rice plant, declined afterwards and reached a very low value after drainage.

Rough estimation of the “N₂-fixing capacity” of each part of the paddy field revealed that the most important site of the N₂ fixation was the reduced Apg horizon, that the importance of flooded water and/or the oxidized layer in the N₂ fixation was rather low except in infertile soil, and that the role of rhizosphere in the N₂ fixation could not be neglected also in Japan.

Reduced condition and content of easily decomposable organic substances were judged to be main factors which control the N₂-fixing activity in the flooded soil on the basis of correlations between the Nt-fixing activity and several analytical data of the paddy soils.