Studies on Ergothioneine. IX. Ergothioneine Stimulates Mouse Spermatozoa and Fertilization in vitro

The effects of ergothioneine on spermatozoa and ova were investigated in vitro and in vivo. Spermatozoa were treated with ergothioneine in vitro , and injected into the uterine cavity of female mice immediately after the induction of superovulation. The ova were recovered 24 hr later and assessed for fertilization. Preincubation of spermatozoa with ergothioneine resulted in a significant increase in the fertilization rate. When ova were inseminated in the same manner in vitro with spermatozoa treated with 0.1 or 1.0 mM of ergothioneine, the penetration rate was significantly increased. These results suggest that ergothioneine is effective in inducing both capacitation and the acrosome reaction of mouse spermatozoa. Ergothioneine at concentrations of 0.1 and 1.0 mM in the preincubation medium was also effective in inducing the acrosome reaction of guinea pig spermatozoa. However, it had no significant effect on the development of 2-cell ova in vitro .     

Effects of forest disturbances on aquatic insect assemblages

Natural and human‐made disasters such as floods and logging occur in and around rivers. Stream‐dwelling aquatic insects respond to these disturbances in various ways. Primary consumers among them rely greatly on algae and leaf litter from riparian vegetation as food. Therefore, once a disturbance such as a flood has occurred, insects may find it difficult to find food in a stream, and the aquatic insect assemblage can be impacted greatly as a result. Disturbances in riparian areas also increase fine sediment loads into streams, damaging habitat and altering the aquatic insect assemblage. Deforestation impacts not only terrestrial but also aquatic animals. In this review paper, aquatic insect assemblages are assessed according to alterations in land use in and around streams. Following this paper, it is expected that clarification of aquatic insect fauna and their life cycles will progress and that the distribution and habitat use of aquatic insects will be afforded greater attention in forest management.     

CD／5-FC自杀基因治疗系统对恶性人脑胶质瘤细胞影响的离体研究

在离体条件下探讨CD/5 FC自杀基因治疗系统对恶性人脑胶质瘤细胞的抗癌作用。通过将CD基因插入真核表达载体pcDNA3.0多克隆位点构建pCMVCD表达质粒 ,采用限制性内切酶消化鉴定所构建的质粒 ,并进行CD基因测序。采用LipofectAMINE2 0 0 0脂质体介导法将CD基因转染U2 5 1恶性人脑胶质瘤细胞 ,G4 18筛选获得抗性克隆 (取名为U2 5 1/CD细胞 ) ,使用不同浓度的 5 FC作用于U2 5 1/CD细胞 ,MTT法测定活性细胞比率。采用高效液相色谱法 (HPLC)检测 5 FC培养液内 5 FU的浓度。结果如下 :真核表达质粒pCMVCD构建成功 ,并通过酶切鉴定。U2 5 1细胞获得了质粒的成功转染。未转染的U2 5 1细胞对 5 FC不敏感 ,IC50 约为 6 5 0 0 μmol/L ,而转染基因后IC50 约为 10 μmol/L。基因转染使G4 18抗性细胞(U2 5 1/CD细胞 )对 5 FC高度敏感。并且加入不同浓度的 5 FC后 ,U2 5 1/CD细胞培养液内均能检测到 5 FU。实验结果表明 :CD/5 FC系统可以用于胶质瘤的治疗 ,CD基因修饰U2 5 1细胞及其表达的离体研究为胶质瘤基因治疗的在体研究提供依据。     

普遍野生稻和亚洲栽培稻遗传多样性的研究

用 ４４个 ＲＦＬＰ标记对来自中国、印度、泰国等亚洲 １０个国家的普通野生稻（简称普野,下同）和来自多个国家的７５个栽培稻品种,从多态位点的比率、等位基因数、基因型数、平均杂合度及平均基因多样性等多个方面,比较了不同国家和不同地区的普通野生稻、栽培稻籼粳亚种及栽培稻与普野之间遗传多样性的差异。结果表明：中国普野的遗传多样性最大;其次是印度普野;南亚普野的平均基因多样性大于东南亚普野,而多态位点的比率、等位基因数及基因型数等却低于东南亚普野;栽培稻的遗传多样性明显小于普通野生稻。在所检测的４４个位点中,栽培稻的多态位点数仅为野生稻的３／４,等位基因数约为野生稻的６０％,基因型种类约为野生稻的１／２。栽培稻中籼稻的遗传多样性高于粳稻。在平均每个位点的实际杂合度上,以中国普野杂合度最高,普通野生稻是栽培稻的２倍。说明从野生稻演化成栽培稻的过程中,经过自然选择和人工选择,杂合度降低,等位基因减少,基因多样性下降。     

普通野生稻和亚洲栽培稻遗传多样性的研究

用４４个ＲＦＬＰ标记对来自中国、印度、泰国等亚洲１０个国家的普通野生稻（简称普野,下同）和来自多个国家的７５个栽培稻品种,从多态位点的比率、等位基因数、平均杂合度及平均基因多样性等多个方面,比较了不同国家和不同地区的普通野生稻、栽培稻灿粳亚种及栽培与普野之间遗传多样性的差异。结果表明：中国普野的遗传多样性最大;其次是印度普野;南亚普野的平均基因多样性大于东南亚普野;而多态位点的比率、等位基因数及基     

Irradiance heterogeneity within crown affects photosynthetic capacity and nitrogen distribution of leaves in Cedrela sinensis

Because light conditions in the forest understory are highly heterogeneous, photosynthetic acclimation to spatially variable irradiance within a crown is important for crown‐level carbon assimilation. The effect of variation in irradiance within the crown on leaf nitrogen content and photosynthetic rate was examined for pinnate compound leaves in saplings of Cedrela sinensis, a pioneer deciduous tree. Five shading treatments, in which 0, 25, 50, 75 and 100% of leaves were shaded, were established by artificial heavy shading using shade screen umbrellas with 25% transmittance. Although the nitrogen content of leaves was constant regardless of shading treatment, ribulose 1·5‐bisphosphate carboxylase/oxygenase (Rubisco) content and light‐saturated photosynthetic capacity were lower in shade leaves within partially shaded crowns than within fully shaded crowns. Shade leaves within partially shaded crowns contained higher amount of amino acids. Most shade leaves died in partially shaded crowns, whereas more than half of shade leaves survived in totally shaded crowns. Assumptions on photosynthetic acclimation to local light conditions cannot explain why shade leaves have different photosynthetic capacities and survival rates in between partially and totally shaded crowns. Irradiance heterogeneity within the crown causes a distinct variation in photosynthetic activity between sun and shaded leaves within the crown.     

Genetic diversity increases regional variation in phenological dates in response to climate change

Climate change is inducing changes in the phenological timings of organisms. Genetic diversity could influence phenological responses to climate change, but empirical evidence is very limited. We estimated the regional variation across Japan in flowering and leaf budburst dates of plants based on a dataset of phenological timings from 1953 to 2005. The observed plants' genetic diversities varied according to human cultivation. The within-species variations of phenological response to temperature as well as regional variations were less in the plant populations with lower genetic diversity. Thus, genetic diversity influences the variation in phenological responses of plant populations. Under increased temperatures, low variation in phenological responses may allow drastic changes in the phenology of plant populations with synchronized phenological timings. Our findings indicate that we should pay attention to maintaining genetic diversity of populations to alleviate changes in phenology due to future climate change.     

TOTAL CELL NUMBER AND NUMBER OF THE PRIMARY MESENCHYME CELLS IN WHOLE, 1/2 AND 1/4 LARVAE OF CLYPEASTER JAPONICUS*

Total cell number and number of the primary mesenchyme cells of 1/2 and 1/4 larvae were counted at several developmental stages after hatching in comparison with those of a whole larva, using Clypeaster japonicus as material. To obtain partial larvae, blastomeres were isolated at the 2- or 4-cell stage in Ca-free sea water and cultured in natural sea water at around 23°C. Isolated blastomeres cleaved as in situ, namely, as a part of an embryo. Although each partial embryo tended to spread into a plate, it acquired spherical shape prior to hatching of control whole embryo and developed normally in terms of both developmental rate and morphogenesis. Total cell number of a whole larva was about 620 just after hatching and increased almost linearly until i t reached 1850 at the pluteus stage. A half and quarter larvae contained roughly 1/2 and 1/4, respectively, of the number of cells of whole larva through all stages counted. Numbers of the primary mesenchyme cells in the partial larvae, however, tended to be slightly larger than a half or a fourth of that in whole larva. In whole larva, 35, 50, 56 and 58 was counted at the mesenchyme blastula, early gastrula, late gastrula and pluteus stage, respectively.