Vacuolar control of subcellular cation distribution is a key parameter in the adaptation of Debaryomyces hansenii to high salt concentrations.

Debaryomyces hansenii is a halotolerant and Na+-includer yeast that can be isolated from different food and low-water activity products. It has also been defined as a marine-occurring yeast but key aspects for this salt tolerant behavior are far from being understood. Here, we searched for clues helping to elucidate the basis of this ability. Our results on growth, Rb+ transport, total K+ and Na+ content and vacuolar fragmentation are compatible with a yeast species adapted to cope with salt stress. On the other hand, we confirmed the existence of D. hansenii strategies that are generally observed in sensitive organisms, such as the production of glycerol as a compatible solute and the efficient vacuolar sequestration of Na+. We propose a striking role of D. hansenii vacuoles in the maintenance of constant cytosolic K+ values, even in the presence of extracellular Na+ concentration values more than two orders of magnitude higher than extracellular K+. Finally, the ability to deal with cytosolic Na+ levels significantly higher than those found in S. cerevisiae, shows the existence of important and specific salt tolerance mechanisms and determinants in D. hansenii.

[Diagnosis of peripheral neuropathies: syndromic, topographic, and etiological diagnoses]. / Diagnóstico das neuropatias periféricas: diagnósticos sindrômicos, topográficos e etiológicos.

A retrospective study was conducted to identify the syndromic, topographic and etiological diagnoses made for a group of 209 patients with peripheral neuropathies. Anamnesis and clinical-neurological examination were of fundamental importance for the syndromic and topographic diagnoses. Electromyography played an important role, especially with respect to the topographic diagnoses. The etiological diagnoses depended on additional complementary tests such as: blood glucose levels and blood glucose tolerance test; nutritional evaluation; family evaluation; nerve, skin, pharynx and maxillary sinus biopsies; qualitative tests for the presence of porphyrins in urine; urinary levels of delta-aminolevulinic acid and porphobilinogen; and radiological examinations. The most frequently encountered polyneuropathies were those consequent to alcoholism or to diabetes, and those of the acute demyelinating inflammatory or hereditary type. Among the cases of mononeuropathy, the most frequently diagnosed conditions were carpal tunnel syndromes, traumatic injury to the VII cranial nerve, and trigeminal neuralgias. Leprosy, brachial plexus injury and thoracic outlet compression syndrome predominated among the multineuropathies.