Ammonia as an important nitrogen source for the photosynthetic growth of Rhodospirillum rubrum

The growth of Rhodospirillum rubrum strain K was poor in a glutamatemalate(G-3-X) medium under light-anaerobic conditions. The supplementof ammonia to the G-3-X medium remarkably stimulated the growth.No such stimulation by ammonia was observed under dark-aerobicconditions. The other bacterium, strain M, also showed a similartendency for the ammonia requirement, though its growth in theG-3-X medium was much more abundant as compared to that of strainK. Casamino acid was found to contain stimulating factors for growth.Among the amino acids, arginine and/or histidine were effective.The other factor in casamino acid was found to be ammonia. The crude extracts of strains K and M contained glutamic dehydrogenaseas judged by the formation of glutamate from -ketoglutarateand ammonia. The highly reduced state of the cell componentsunder lightanaerobic conditions, appears to limit the formationof ammonia from glutamate. Ammonia was a preferable nitrogensource to glutamate under the conditions employed. ¹Present address: Institute for Agricultural Research, TohokuUniversity, Sendai. ²Present address: Sanitary Engineering Research Laboratory,Sanitary Engineering Department, Sumitomo Machinery Co. Ltd.,Hiratsuka.     

Cytoplasmic control of mitosis in true slime mold, Physarum polycephalum

To resolve the problem of whether mitosis is controlled by anuclear or cytoplasmic stimulus, plasmodia from various periodsof the mitotic cycle were fused with one another. Mitosis inthe fused plasmodiura occurred about midway between mitosesof the donors. Treatment with cyclohcximide during the G₂-period.delayed the next mitosis for a period equal to the time of treatment. (Received March 2, 1971; )     

Effect of Ca2+ on the retention of glycerol and amino acids in Dunaliella tertiolecta

When D. tertiolecta cells, previously incubated in a 0.5 kmol m⁻³ NaCl medium with 1mol m⁻³ Ca²⁺, were transferred to an isotonic NaCl medium without Ca²⁺, the intracellular glycerol, as well as intracellular amino acids, was transiently lost to the medium within 30 min. The transient leakage of glycerol and amino acids was enhanced by the addition of EGTA (1 mol m⁻³), while the addition of SrCl₂ (1 mol m ⁻³) or polyamines such as spermidine (5 mol m⁻³) and spermine (5 mol m⁻³) restrained the leakage caused by the lack of external Ca²⁺ of intracellular glycerol and amino acids.     

Chromosomal localization of silkworm (Bombyx mori) sericin gene 1 and chymotrypsin inhibitor 13 using fluorescence in situ hybridization

The chromosomal locations of two single-copy genes, Ser-1 and CI-13, in silkworm (Bombyx mori) were detected at the molecular cytogenetics level by fluorescence in situ hybridization in the study. The results showed that Ser-1 is located near the distal end of the 11th linkage group, relatively at the 12.5±1.4 position in pachytene; and that CI-13 has been mapped near the distal end of the 2nd linkage group, relatively at the 8.2±1.2 position in pachytene. Furthermore, their location model map-FISH map on silkworm chromosome was drawn. The FISH technique and its application to silkworm are also discussed in this paper.     

应用飞秒时间分辨瞬态吸收光谱研究蛋白质中距离相关长程电荷转移：光合细菌天线复合体LH2与TiO2纳米颗粒超分子组装体个例初探

蛋白质在生物体内电荷转移过程中所起的作用迄今仍然是一个有争议的问题,其争论焦点是蛋白质在生物电荷转移过程中是否提供特殊的电子传递通道或者是仅仅作为普通的有机介质。应用飞秒时间分辨瞬态吸收光谱研究由光合细菌天线分子和平均粒径为8nm的TiO2组装而成的超分子系统中长程电荷转移,晶体结构研究表明,光合细菌天线分子具有由多个α-脱辅基和β-脱辅基蛋白跨膜螺旋构成的双层空心柱面体结构,其中α-脱辅基蛋白跨膜螺旋构成的小环状体套于β-脱辅基蛋白跨膜螺旋构成的大环状体中,小环状体的空腔直径约为3.6nm。光合色素细菌叶绿素和β-胡萝卜素分子处于两环之间。细菌叶绿素距离外周胞质膜最近,预计为1nm。本研究试图将TiO2纳米颗粒部分装入光合细菌膜蛋白的腔体中,探讨细菌叶绿素与TiO2纳米颗粒间进行的光致长程电荷转移,进而揭示蛋白质在电荷转移过程中所起的作用。实验观察到细菌叶绿素B850在LH2/TiO2中的基态漂白恢复的时间常数明显地比在LH2中短,应用长程电荷转移模型。将蛋白质视为普通介电媒体。由电荷转移速率推算得到细菌叶绿素与TiO2纳米颗粒最近表面的距离为0.6nm。表明TiO2纳米颗粒已经成功地部分装入光合细菌天线分子的空腔中。     

Non-histone Proteins Associated with Chromatin of Spirogyra during the Conjugation Process

Non-histone proteins were isolated from purified chromatin of Spirogyra sp. at different stages of the life cycle. Conjugation- specific acidic proteins were separated by DEAE-Sephadex A50 column chromatography. The protein fraction includes an inhibitor of chromatin-directed RNA synthesis.     

PHYSIOLOGY OF LIGHT-REQUIRING GERMINATION IN ERAGROSTIS SEEDS

The photorequirement for the germination of Eragrostis seedsdecreases with the progress of their after-ripening, and thegermination occurs whether in continuous light or in darknessat the final stage of after-ripening. The dehydration of seedsor the puncturing of seed coats also results in a decrease ofphotorequirement for germination. The rate of water absorptionof seeds increases with the germination capacity under continuousdark condition. However, there is no correlation between therespiration rate and the germination capacity; respiration isstimulated in the punctured seeds, but not in the after-ripenedseeds. The after-ripened or punctured seeds which no longer have aphotorequirement become light-sensitive again, when they areallowed to germinate in the air of low oxygen concentrations.The assumption is presented that the permeability to oxygenof the seed coat may be a factor controlling the seed germinationof this species. (Received August 21, 1964; )