Unraveling the Diversity of GJB2 Mutations in Nonsyndromic Hearing Loss: A Comprehensive Study in the Moroccan Population.

Introduction: Despite the high genetic heterogeneity of hearing loss, mutations in the GJB2 gene are a major cause of autosomal recessive nonsyndromic hearing loss (NSHL) worldwide. However, the mutation profile of GJB2 in NSHL is under-investigated in Morocco, especially among simplex cases. This study aimed to identify the spectrum and frequency of GJB2 mutations in the Moroccan population among simplex and multiplex families with NSHL.

Immune activation and regulatory T cells in Mycobacterium tuberculosis infected lymph nodes.

Background: Lymph node tuberculosis (LNTB) is the most frequent extrapulmonary form of tuberculosis (TB). Studies of human tuberculosis at sites of disease are limited. LNTB provides a unique opportunity to compare local in situ and peripheral blood immune response in active Mycobacterium tuberculosis (Mtb) disease.

[Cervical tuberculous lymphadenitis: the location of surgery].

Introduction: In spite of the current effectiveness of antibacillary chemotherapy in most tubercular sites, peripheral lymph node involvement continues to pose a challenge to treatment.

Patients And Methods: It is a retrospective study, from 2002 to 2005, of 326 patients treated at the otorhinolaryngology department of Hassan II University Hospital, Fez, Morocco, for cervical lymph node tuberculosis.

Results: The tuberculosis of lymph nodes accounts for more than 23% of all affections managed in our department.

Arg82p is a bifunctional protein whose inositol polyphosphate kinase activity is essential for nitrogen and PHO gene expression but not for Mcm1p chaperoning in yeast.

In Saccharomyces cerevisiae, the synthesis of inositol pyrophosphates is essential for vacuole biogenesis and the cell's response to certain environmental stresses. The kinase activity of Arg82p and Kcs1p is required for the production of soluble inositol phosphates. To define physiologically relevant targets of the catalytic products of Arg82p and Kcs1p, we used DNA microarray technology.

Yeast epiarginase regulation, an enzyme-enzyme activity control: identification of residues of ornithine carbamoyltransferase and arginase responsible for enzyme catalytic and regulatory activities.

In the presence of ornithine and arginine, ornithine carbamoyltransferase (OTCase) and arginase form a one-to-one enzyme complex in which the activity of OTCase is inhibited whereas arginase remains catalytically active. The mechanism by which these nonallosteric enzymes form a stable complex triggered by the binding of their respective substrates raises the question of how such a cooperative association is induced. Analyses of mutations in both enzymes identify residues that are required for their association, some of them being important for catalysis.

The proper folding of a long C-terminal segment of the yeast Lys14p regulator is required for activation of LYS genes in response to the metabolic effector.

Transcription of lysine genes in Saccharomyces cerevisiae is dependent on Lys14p and on alpha-aminoadipate semialdehyde (alphaAASA), an intermediate of the pathway. The two-thirds C-terminal end of Lys14p is sufficient to ensure the activation function of the protein and its modulation by alphaAASA. Here, we show that no single discrete domain of Lys14p is able to activate transcription and that most of the deleted LexA-Lys14p proteins are inactive even in the presence of a high alphaAASA concentration.