Metronidazole and tinnitus: A potential side effect?

As a healthcare profession, dentists have a role in ensuring the safety of prescribed medicines by reporting adverse drug reactions using the Yellow Card Scheme. This article briefly describes a case where metronidazole, an antibiotic commonly prescribed by dentists, may have caused ototoxicity and explores the evidence around this. It also highlights the method for reporting such effects.

bimA encodes a member of the tetratricopeptide repeat family of proteins and is required for the completion of mitosis in Aspergillus nidulans.

The recessive, temperature-sensitive bimA1 mutation of Aspergillus nidulans blocks nuclei in metaphase at restrictive temperature. To determine whether the bimA product is essential, integrative transformation was used to create a mutation in the bimA gene. The mutation was maintained in a heterokaryon and the phenotype of spores produced by the heterokaryon was analyzed. Molecular disruption of the wild-type bimA gene is recessive in the heterokaryon and causes a metaphase block, demonstrating that bimA is an essential gene for mitosis. bimA was cloned by DNA-mediated complementation of its mutant phenotype at restrictive temperature, and the nucleotide sequence of a full-length cDNA was determined. A single large open reading frame was identified in the cDNA sequence, which predicts a protein containing 806 amino acid residues that is related (30.4% identity) to the Schizosaccharomyces pombe nuc2+ gene product, which also is required for completion of mitosis. The sequence of the bimA gene indicates that it is a member of a family of mostly nuclear proteins that contain a degenerate 34 amino acid repeat, the TPR (tetratricopeptide repeat) gene family.

The organization of microtubules during anaphase and telophase spindle elongation in the rust fungus Puccinia.

The entire framework of microtubules (MTs) in the meiotic spindle of the rust fungus Puccinia has been reconstructed during the later stages of meiosis I, by tracking MTs through transverse serial sections. This spindle is of special interest because it elongates considerably during anaphase spindle elongation, from 5 microns at metaphase to 15 microns at telophase. The spindle is composed mainly of MTs from opposite poles which interdigitate or overlap in the middle of the spindle. In the overlap region, MTs from one pole seek out as near neighbors, MTs from the opposite pole at a preferred spacing of 43 to 55 nm. During anaphase elongation three changes in spindle structure occur: 1) the region of overlap decreases, but this reduction in overlap cannot account for all the increase in spindle length; 2) interdigitated MTs (MTs from one pole that are within 80 nm of a MT from the opposite pole) dramatically increase in length by MT polymerization and; 3) kinetochore MTs, free MTs (those unattached to the poles) and non-interdigitated polar MTs shorten and disappear. The mechanism of anaphase elongation and the control over MT polymerization and depolymerization during anaphase are discussed.