Hyphal cells of filamentous fungi grow at their tips in a method analogous to pollen tube and root hair elongation. This process, generally referred to as tip growth, requires precise regulation of the actin cytoskeleton, and characterizing the various actin structures in these cell types is currently an active area of research. Here, the actin marker Lifeact was used to document actin dynamics in the filamentous fungus Aspergillus nidulans. Contractile double rings were observed at septa, and annular clusters of puncta were seen subtending growing hyphal tips, corresponding to the well-characterized subapical endocytic collar. However, Lifeact also revealed two additional structures. One, an apical array, was dynamic on the face opposite the tip, while a subapical web was dynamic on the apical face and was located several microns behind the growth site. Each was observed turning into the other over time, implying that they could represent different localizations of the same structure, although hyphae with a subapical web grew faster than those exhibiting an apical array. The subapical web has not been documented in any filamentous fungus to date, and is separate from the networks of F-actin seen in other tip-growing organisms surrounding septa or stationary along the plasmalemma.

Objectives: This study sought to investigate the prevalence of atrial septal aneurysms in the paediatric population and to define coexisting abnormalities and their incidence. Background: Few papers refer to the prevalence of atrial septal aneurysms in childhood. Methods: We enrolled a total of 4522 children aged more than 12 months who underwent a transthoracic echocardiography. Atrial septal aneurysm was defined as a protrusion of the interatrial septum or part of it >15 mm beyond the plane of the atrial septum or phasic excursion of the interatrial septum during the cardiorespiratory cycle of at least 15 mm in total amplitude and a diameter of the base of the aneurysm of at least 15 mm. Results: Atrial septal aneurysms were found in 47 children (1.04%). They involved almost the entire septum in 14 patients (28.89%) and were limited to the fossa ovalis in 33 (71.11%). An atrial septal aneurysm was an isolated structural defect in 17 (35.56%). In 30 (64.44%) patients, it was associated with interatrial shunting – atrial septal defect and patent foramen ovale. At the echo follow-up after a year, no changes were recorded. Conclusions: Prevalence of atrial septal aneurysms is almost 1%. The most common abnormalities associated are interatrial shunts, that is, a patent foramen ovale and an atrial septal defect. From a medical point of view, it is suggested that no action is to be taken during childhood, as a child with an atrial septal aneurysm is not at increased risk compared with a child without one. Follow-up is scheduled on an individual basis.

Eosinophilic angiocentric fibrosis (EAF) is a rare inflammatory fibrosing condition of unknown aetiology that involves the nose or larynx producing mucosal thickening and severe obstructive symptoms. We report the first case affecting a male. He presented with nasal obstruction requiring septoplasty. The clinical and histopathological features of the condition are discussed and a comparison is made with the seven previous reported cases.

Raphe-like vestiges have been found regularly in two new taxa which presumably belong to Fragilaria, one of them livingin several lakes of the Kerguelen Islands, the other in the Yellowstone National Park, Wyoming, U.S.A. The latter onepossesses septa-like elements as integrated parts of a girdle band. Other septa-like elements can occur in different speciesof Fragilaria. They represent appendices of the valvocopula, located beneath the transapical costae. Structures like linkingspines on marginal parts of the valve face occur in an Achnanthes species. Most of these characters seem to havebeen unknown in these taxa until recently.