Further Observations on Root Contraction

Further observations, by light and electron microscopy, on theanatomy of root contraction in Hyacinthus orientalis cvs. arereported, together with some comparisons with Narcissus andGladiolus. It is maintained that root contraction in these andsome other species is essentially a growth process, as previousinvestigators have shown, and that an understanding of the re-directedgrowth of the cortical cells which brings it about may be basedon the specialized structural features of their cell walls,here described. Physical, anatomical and comparative reasonsare given for our belief that the alternative explanation ofthe contractile process in Gladiolus which relates it to cellcollapse resulting from transpirational ‘pull’ isuntenable. anatomy, contraction, Hyacinthus, Narcissus, Gladiolus, root     

Further Observations on Acetylcholine Noise

THERE have been several reports of plant cell wall regeneration^1–4 and two reports of division following protoplast formation^{3, 4} but only one of sustained cell division³.     

Further Observations on the Pathogenesis of Acne

The composition of the lipid of the forehead skin surface and the sebum excretion rate were determined in 217 subjects and controls. Acne was associated with an increase in serum excretion rate and in the squalene and wax and sterol esters in surface lipid. The changes in sebum excretion rate and squalene were statistically significant only in women, but acne in men was associated with a significant decrease in the free fatty acid content or surface lipid.The increased amounts of squalene and wax esters may lead to pilosebaceous obstruction in acne subjects. The increased sebum excretion rate in acne may ensure increased production of sebaceous triglyceride substrate available for lipolysis to irritant free fatty acids, which may then mediate the inflammatory changes of acne.     

Further Observations on Asymmetrical Solute Movement across Membranes

The permeability of frog skin under the influence of urea hyperosmolarity has been studied. Flux ratio asymmetry has been demonstrated again for tracer mannitol. The inhibitors DNP, CN^-, and ouabain have been used to eliminate active sodium transport and it was found that urea hyperosmolarity produces asymmetrical mannitol fluxes on frog skins having no short-circuit current. These findings suggest that flux ratio asymmetry is due to solute interaction and is unrelated to sodium transport. Studies with a synthetic membrane show clearly that bulk flow of fluid can produce a "solvent drag" effect and change flux ratios. When bulk flow is blocked and solute gradients allowed their full expression, then solute interaction "solute drag" is easily demonstrable in a synthetic system.