Cell surface galactosylation is essential for nonsexual flocculation in Schizosaccharomyces pombe.

We have isolated fission yeast mutants that constitutively flocculate upon growth in liquid media. One of these mutants, the gsf1 mutant, was found to cause dominant, nonsexual, and calcium-dependent aggregation of cells into flocs. Its flocculation was inhibited by the addition of galactose but was not affected by the addition of mannose or glucose, unlike Saccharomyces cerevisiae FLO mutants. The gsf1 mutant coflocculated with Schizosaccharomyces pombe wild-type cells, while no coflocculation was found with galactose-deficient (gms1Delta) cells. Moreover, flocculation of the gsf1 mutant was also inhibited by addition of cell wall galactomannan from wild-type cells but not from gms1Delta cells. These results suggested that galactose residues in the cell wall glycoproteins may be receptors of gsf1-mediated flocculation, and therefore cell surface galactosylation is required for nonsexual flocculation in S. pombe.

Iodine deficiency disorders in the Maldives: A public health problem.

Because the Maldives is a country of islands it has been assumed, until now, that iodine deficiency disorders (IDD) are not a public health problem. However, no systematic scientific survey has been carried out to assess the status of IDD in the Maldives. This study represents the first IDD survey by the Government of the Republic of Maldives in association with UNICEF Maldives. Undertaken during June and July 1995, the survey adopted the EPI 30 Cluster sampling technique, as recommended by the Joint WHO/UNICEF/ICCIDD Consultation. Based on population proportion to size, a total of 30 clusters were chosen from sampling frames of all 200 islands. A total of 30 schools and 2834 children aged 6-12 years were surveyed. The total goitre rate was 23.6%, with grade 1 goitre contributing 22.5% of this figure. The prevalence of goitre was greater in girls (26.6%) than in boys (20.7%). The median urinary iodine level was 6.7 µg/dL and 65.5% of children had urinary iodine levels below 10 µg/dL. It is evident from this survey that IDD is a public health problem in the Maldives. Hence, efforts to control IDD should be instituted. The most common method of iodine supplementation is iodised salt. As tested in a non-representative sample of 39 salt samples, only 8% of salt had adequate iodine levels of approximately 15 p.p.m. Because all the atolls are affected there is a need to introduce universal salt iodization in the country.