No abstract

No abstract

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Some bacteria belonging to the genera Arthrobacter, Brevibacterium and Corynebac-.terium, so-called glutamic acid-producing bacteria, are highly important as they are used for the industrial fermentation production of various amino acids. The genetic breeding of such amino acid-producing strains has so far been carried out by conventional mutation and selection methods. After a phenol treatment of the supernatant, DNAwas recovered as ethanol precipitation. These DNA samples were analysed by agarose gel electrophoresis with a Tris-acetate buffer system as described by Sharp et al.7) As a result of the screening, two low-molecular-weight plasmids were found. One was found in Brevibacterium lactofermentum ATCC13869 Recentlyand named pAM330.The other was found in Corynebacterium glutamicum ATCC1 3058 and named pHM1519. They were purified.by the CsCl-EtBr equilibrium density gradient centrifugation method, and were confirmed to exist as closed circular molecules. The molecular weights of pAM330 and pHM1519 were determined as 3.0 Md and 1.8 Md, respectively, from electrophoretic mobility in a 0.8% agarose gel. Restriction enzyme analysis was carried out on those plasmids, and the results are shown in Fig. 1. The contents of pAM330 and pHM1519 were roughly analysed by the agarose gel electrophoresis method8'9* as follows: Cells were cultured in 4ml of the CM2Gmediumto the exponential growth phase, and 600 jig/ml of ampicillin was added to the culture medium to ensure the lysozyme digestion. The cells were harvested at 2.5 hr after the addition of ampicillin, and were lysed with lysozyme (lOmg/ml, 37°C 2hr) and SDS (4%). The lysis was completed by heating at 65°C for lOmin, followed by phenol extraction and ethanol precipitation. The DNAsamples were dissolved in TEN buffer and treated with RNase (20/ig/ml, 37°C fir 20min) and pronase (100/^g/ml, 37°C for 20min) sequentially.After phenol extraction and ethanol precipitation, the recovered DNAwas dissolved in TENbuffer, and electrophoresed in a 0.8% agarose gel. The photographs of the gel were taken under irradiation by ultra-violet light, and the negative films of them were analysed by a densitometer (Shimadzu CS-910). As a result, the amounts ofpAM330 and pHM1519 were approximately 1.4% and 9.1% of the total DNA, respectively.To estimate the

The opening of the Japan Sea backarc basin accompanied dextral, transtensional deformations in the NE Japan arc. To understand the intra-arc deformation we have studied paleomagnetism in the Uetsu area, NE Japan. Among the samples collected at 70 sites for paleomagnetic measurement reliable directions were obtained at 38 ones. About half of the sites yielded clockwise and the others show opposite declinations. Our data indicate that the northern Uetsu area rotated counterclockwise as a single block, whereas the southern Uetsu area was broken into a number of blocks that was rotated clockwise by the dextral transtension along the Nihonkoku-Miomote Line. Not only the Uetsu area but the entire eastern margin of the Japan Sea experienced such transtensional deformations in the Early to early Middle Miocene. The crust under NE Japan was broken into blocks but they rotated coherently with dextral transtension.