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INDIRECT immunofluorescent techniques show that the sera of patients with pemphigus vulgaris contain immunoglobulins (IgG) which specifically bind to the presumed site of the intercellular space of stratified squamous epithelia1–3. Pretitres of these diagnostic antibodies reflect the progress of the disease as well as the patient's response to treatment4. There is considerable evidence that the IgG immunoglobulins1,5 and complement6 found in the intercellular spaces represent autoantibodies4. These data imply that the distribution of the IgG deposits corresponds to the primary lesion in this disease7,8.

IN epithelia classified as “leaky”, net transport efficiency of NaCl and water may be determined not only by cellular metabolic activity, but also by tight junction permeability and the conjugate physical driving forces acting between lumen and intercellular space. The significance of paracellular ion movement across leaky epithelia would become more apparent if a cytoplasmic mechanism for regulation of tight junctional permeability could be defined. The structure–function observations reported here suggest that the microfilament system may have such a function. Rapid and reversible increases in shunt path electrical resistance were observed in Necturus gallbladder exposed to plant cytokinins. In electron micrographs zeiotic transformation of the luminal membrane was associated with disruption of microfilaments and in freeze fracture, with reorientation and disorder of tight junctional elements.

IN a recent communication, Rees1 reported that midday closure in the oil palm was associated with water-strain and correlated in extent with total evaporation. There was also a relation with air temperature showing striking stomatal closure between 30° and 35° C., strongly reminiscent of the results of Heath and Orchard2 for the log Γ/leaf temperature relation in onion and coffee leaves and of those of Heath and Meidner3 for the stomatal aperture/leaf temperature relation in onion leaves closed at the tip. Rees concludes: “Although increasing leaf temperature may cause stomatal closure, it is clear that midday closure of stomata may also be influenced by water-strain …”. In work carried out with wheat leaves we found a relation between degree of water-strain and Γ (the minimum intercellular space carbon dioxide content2) which is very relevant to this conclusion.

Midday Closure of Stomata: Temperature Effects on the Minimum Intercellular Space Carbon Dioxide Concentration “Γ”