A Rich and Highly Endemic Decapod Crustacean Fauna from the Middle Jurassic of North-east France

Decapod crustaceans are relatively widespread in Jurassic deposits of Europe and a small number have been collected from the north-east of France. A new fossil of a macrurous decapod assigned to Eryma burgundiaca sp. nov., an erymid lobster, is described from this area and comparisons are made with closely allied species from Europe. Probable pagurid anomurous decapods are represented by Orhomalus magnificus sp. nov., Palaeopagurus acutus sp. nov. and Palaeopagurus neraudeaui sp. nov. No brachyurous decapods are presently known from the fauna. Based on the associated ammonites, the material is considered to be Callovian in age.     

Plasmid stability in immobilized and free recombinant Escherichia coli JM105(pKK223-200): importance of oxygen diffusion, growth rate, and plasmid copy number

Stability of the plasmid pKK223-200 in Escherichia coli JM105 was studied for both free and immobilized cells during continuous culture. The relationship between plasmid copy number, xylanase activity, which was coded for by the plasmid, and growth rate and culture conditions involved complex interactions which determined the plasmid stability. Generally, the plasmid stability was enhanced in cultured immobilized cells compared with free-cell cultures. This stability was associated with modified plasmid copy number, depending on the media used. Hypotheses are presented concerning the different plasmid instability kinetics observed in free-cell cultures which involve the antagonistic effects of plasmid copy number and plasmid presence on the plasmid-bearing/plasmid-free cell growth rate ratio. Both diffusional limitation in carrageenan gel beads, which is described in Theoretical Analysis of Immobilized-Cell Growth, and compartmentalized growth of immobilized cells are proposed to explain plasmid stability in immobilized cells.     

Bactericidal effect of hydrogen peroxide on Salmonella typhimurium in liquid whole egg

The effect of hydrogen peroxide on Salmonella typhimurium in whole egg was evaluated. The bactericidal effects observed on the test organism at 5 degrees and 20 degrees C were found to be similar. There was a 99% kill in the presence of 0.5% and 1.0% H2O2. Addition of the test organism and H2O2 after pre-heating the egg material at 40 degrees C for 15 min caused a rapid kill which was 10,000-fold greater than that produced by H2O2 alone.     

Radioactive labeling techniques for the identification of G antigen in the human Rh blood group system

The G antigen is one of the erythrocyte membrane Rh antigens. The amount of Rh antigen present on the red blood cell is about 10(-15) g and radioactive labeling of membrane proteins is a useful method for its identification and characterization. In this paper, we compare 4 labeling techniques. Using a human monoclonal anti-Rh(G) antibody and an immunofixation technique, we located the G antigen on a polypeptide of an average molecular weight of 28,000 Da.