Exposure of mice to live Pseudomonas aeruginosa generates protective cell-mediated immunity in the absence of an antibody response

In previous studies we have elicited T cell-mediated protective immunity to the extra-cellular Gram-negative bacterium Pseudomonas aeruginosa by administering P. aeruginosa polysaccharide Ag and the anti-mitotic agent vinblastine sulfate to BALB/c mice. The current studies indicate that T cells which inhibit the growth of P. aeruginosa in vitro and protect granulocytopenic mice from P. aeruginosa infection can be generated by exposure of BALB/c mice to as few as 10(2) live bacteria without simultaneous administration of vinblastine. The in vitro inhibition of bacterial growth and mouse protection are P. aeruginosa immunotype specific. Exposure to 10(6) live bacteria is required to elicit a detectable antibody response. These findings indicate a potential role for T cells in resistance to P. aeruginosa infection in the large majority of individuals who lack anti-P. aeruginosa antibody.     

Effect of choline deprivation on the growth, morphology and ultrastructure of a choline-requiring mutant of Aspergillus nidulans

Abstract On minimal medium in the absence of added choline, conidiospores of the cho C3 choline-requiring mutant of Aspergillus nidulans germinated and grew normally for approximately 17 h at 37°C. After this period a characteristic aberant morphology was produced by the swelling of small regions at or close to the majority of hyphal apices, creating spherical structures up to 10 μm in diameter from hyphae which were typically 1–2 μm in diameter. During the swelling of these structures, apical extension showed and stopped. This apparently indicated a switch from polarised to unpolarised growth. Electron microscopic examination of ultrathin sections of the swellings indicated that they had thicker walls (158.2 ± 42.1 nm) than the immediately adjacent hyphae (88.0 ± 17.6 nm) and that wall thickness of the swellings increased with increasing age and size. However, the absence of any accumulation of cytoplasmic vesicles within the swellings indicated that they were not simply produced by diversion that they normal polarised flow of vesicles from the tip to the side walls of hyphae.     

Synthesis of the nascent strand of tRNAfMet from E coli.

Oligonucleotides corresponding to the total tRNAfMET FROM E. coli have been synthesized. These fragments were joined by using RNA ligase to yield quarter molecules. The 5'-quarter molecule showed 84% amino acid acceptor activity when it was combined with the natural three quarter molecule.     

OBSERVATIONS ON THE ECOLOGY OF LAMINARIA SINCLAIRII ON THREE NORTHERN OREGON BEACHES1,2

Laminaria sinclairii (Harvey) Furlow, Anderson and Eaton occurs only on the Pacific Coast, of North America and is usually restricted to rocks on beaches subjected, to moderate to heavy surf and a large seasonal fluctuation in sand level. It was observed and measured over a 2-year period-on 3 such beaches in northern Oregon. Growth, rate and, relative dominance are greatest in the lowest and most exposed parts of the inter tidal zone, where surf action and sand burial are greatest. The sand level begins to build up on the beach in April and continues to rise, burying the plants, throughout the summer, until the first, heavy storms in fall again remove the sand. Maximum growth occurs in early summer, prior to burial. The blades are lost in December and regenerated in January. Ripe sori are produced on the old blades just before they are lost and on the new blades just after they appear. The gametophyles which, develop from spores produced by these sori apparently do not usually produce sporophytes. In March and April there is considerable production of new stipes and blades from the haptera at the margins of the holdfast and this is apparently the chief means of reproduction.     

Dolichins A and B,two pterocarpans from bacteria-treated leaves of Dolichos biflorus

Two minor isoflavonoids isolated from bacteria-inoculated leaves of Dolichos biflorus have been identified as the 6aR; 11aR; 2′S and 6aR; 11aR; 2′S isomers of 3,9-dihydroxy-10-2′-hydroxy-3′-methyl-3′-butenyl pterocarpan.