The PhcA virulence regulator in the vascular wilt pathogen Ralstonia solanacearum responds to cell density via quorum sensing. To understand the timing of traits that enable R. solanacearum to establish itself inside host plants, we created a ΔphcA mutant that is genetically locked in a low-cell-density condition. Comparing levels of gene expression of wild-type R. solanacearum and the ΔphcA mu...

The evidence is now strong that magnesium plays an important role in the interactions between myosin, actin and ATP which are associated with the physiological activity of muscle. Although calcium activates the adenosine triphosphatase ofboth L-myosin and isolated myofibrils, in the presence of this cation alone neither contraction (Ashley, Arasimavicius & Hass, 1956) nor relaxation (Bendall, 1...

1. The antigenicity of four soya-bean-based infant formulas (Prosobee powder, Prosobee liquid concentrate (Mead Johnson, Uxbridge, Middx), Wysoy (Wyeth, Maidenhead, Berks) and Formula S (Cow and Gate, Trowbridge, Wilts] was measured by enzyme-linked immunosorbent assays (ELISAs) specific for glycinin and beta-conglycinin. Results were compared with in vivo assessments of antigenicity using guin...

When high tensions are developed in the water columns within the xylem of a shoot, the shoot wilts. If such wilting is induced by plugging a stem with gelatin immediately upon cutting, very rapid recovery results if the plugged portion is cut off under water in such a way as to prevent the entrance of air into the stem. Such recovery was observed by DIXON and BARLEE (1) as long as no gas entere...

Cephalosporin C, an antibiotic with structure (I) (Abraham & Newton, 1961; Hodgkin & Maslen, 1961), was first isolated from an impure preparation of the chemically related penicillin NJ [(D-4amino-4-carboxybutyl)penicillin] that had been obtained from the culture fluid of a Cephalosporium sp. (Newton & Abraham, 1956; Abraham & Newton, 1956). The amount of cephalosporin C produced by this organi...

report of a series of 16 cases of Hodgkin's disease involving Waldeyer's ring.' In our series there was involvement of the nasopharynx in eight cases but, unlike the Swedish report, our cases were all ones in which biopsy of the nasopharynx was indicated by symptoms related to this area. In two of our patients the disease was primary in the nasopharynx; the other six had more widespread disease...

Higher plants contain potentially vast sources of nutrients for the myriad bacterial species in their environment, and most bacteria are small enough to pass through stomates and other natural openingsinto the apoplast-the anteroom for these riches. However, surprisingly few bacteria raid the nutrient stores of living plant cells, apparently because the metabolic intimacy involved in parasitism...