A method of column chromatographic isolation of major phospholipid components on Escherichia coli

For the column chromatographic isolation of individual phospholipids from the total phospholipid mixture, silicic acid, DEAE cellulose, alumina and others, have been used as adsorbent. However, it must be emphasized that silicic acid (1, 2, 3, 4) is the most useful adsorbent for the separation of the total phospholipid mixture from each other in reasonable purity. VAN DEENEN reported that pure phosphatidyl glycerol was obtained from the lipid fraction of spinach leaves after repeated chromatography on silicic acid column (5). The phospholipid extracted from Escherichia coli B consists of abundant phosphatidyl ethanolamine (70-80 %), cardiolipin, phosphatidyl glycerol and other minor components as described in the previous paper (6). The high percentage content of phosphatidyl ethanolamine renders it difficult to separate the phospholipids by the column chromatography. Therefore, repeated chromatographies on the silicic acid column treated with sodium bicarbonate (7) and normal silicic acid column were employed for the isolation of the major components from the total phospholipid of E. coli B. Stepwise elution (4) was carried out with chloroform containing increasing proportions of methanol, and the eluent was divided into several fractions according to experience with thin-layer chromatography.</p

Transfer RNA Modification Enzymes from Thermophiles and Their Modified Nucleosides in tRNA

To date, numerous modified nucleosides in tRNA as well as tRNA modification enzymes have been identified not only in thermophiles but also in mesophiles. Because most modified nucleosides in tRNA from thermophiles are common to those in tRNA from mesophiles, they are considered to work essentially in steps of protein synthesis at high temperatures. At high temperatures, the structure of unmodified tRNA will be disrupted. Therefore, thermophiles must possess strategies to stabilize tRNA structures. To this end, several thermophile-specific modified nucleosides in tRNA have been identified. Other factors such as RNA-binding proteins and polyamines contribute to the stability of tRNA at high temperatures. Thermus thermophilus, which is an extreme-thermophilic eubacterium, can adapt its protein synthesis system in response to temperature changes via the network of modified nucleosides in tRNA and tRNA modification enzymes. Notably, tRNA modification enzymes from thermophiles are very stable. Therefore, they have been utilized for biochemical and structural studies. In the future, thermostable tRNA modification enzymes may be useful as biotechnology tools and may be utilized for medical science

Ballast saving balloons with a film of specific optical properties

Large plastic balloon play an important role for scientific observations at high altitude in the field of astrophysics and geophysics. In these observations, it has been well recognized that the long duration balloon flights are indispensable for precise observations. For a normal zero pressure balloon, we need to drop ballast to keep a level altitude during day and night to prevent from altitude excursions. This is due to the temperature change of lifting gas, and the duration of the balloon is limited when all the ballast on board the balloon has been exhausted. In this paper, we discuss a possibility of minimizing the temperature variation of the lifting gas using specific balloon films with suitable optical properties and show the optical properties of some test films for this purpose

Required Elements in tRNA for Methylation by the Eukaryotic tRNA (Guanine-N2-) Methyltransferase (Trm11-Trm112 Complex)

The Saccharomyces cerevisiae Trm11 and Trm112 complex (Trm11-Trm112) methylates the 2-amino group of guanosine at position 10 in tRNA and forms N2-methylguanosine. To determine the elements required in tRNA for methylation by Trm11-Trm112, we prepared 60 tRNA transcript variants and tested them for methylation by Trm11-Trm112. The results show that the precursor tRNA is not a substrate for Trm11-Trm112. Furthermore, the CCA terminus is essential for methylation by Trm11-Trm112, and Trm11-Trm112 also only methylates tRNAs with a regular-size variable region. In addition, the G10-C25 base pair is required for methylation by Trm11-Trm112. The data also demonstrated that Trm11-Trm112 recognizes the anticodon-loop and that U38 in tRNAAla acts negatively in terms of methylation. Likewise, the U32-A38 base pair in tRNACys negatively affects methylation. The only exception in our in vitro study was tRNAValAAC1. Our experiments showed that the tRNAValAAC1 transcript was slowly methylated by Trm11-Trm112. However, position 10 in this tRNA was reported to be unmodified G. We purified tRNAValAAC1 from wild-type and trm11 gene deletion strains and confirmed that a portion of tRNAValAAC1 is methylated by Trm11-Trm112 in S. cerevisiae. Thus, our study explains the m2G10 modification pattern of all S. cerevisiae class I tRNAs and elucidates the Trm11-Trm112 binding sites

International Journal of Offender Therapy and Comparative Criminology Responding to Threats of Violence Weapon Ownership and the Willingness to Respond to Threats With Violence: The United States and Japan

Abstract: Using data collected i