The synthesis of novel chromogenic enzyme substrates for detection of bacterial glycosidases and their applications in diagnostic microbiology

The preparation and evaluation of chromogenic substrates for detecting bacterial glycosidase enzymes is reported. These substrates are monoglycoside derivatives of the metal chelators catechol, 2,3-dihydroxynaphthalene (DHN) and 6,7-dibromo-2,3-dihydroxynaphthalene (6,7-dibromo-DHN). When hydrolysed by appropriate bacterial enzymes these substrates produced coloured chelates in the presence of ammonium iron(III) citrate, thus enabling bacterial detection. A β-d-riboside of DHN and a β-d-glucuronide derivative of 6,7-dibromo-DHN were particularly effective for the detection of S. aureus and E. coli respectively.     

Excess of unpaired males in one of the World's most endangered seabirds, the Chatham Island taiko Pterodroma magentae

The Chatham Island taiko Pterodroma magentae (tchaik) is one of the World's most endangered seabirds with a population size of between 120–150 individuals that includes only 8–15 breeding pairs. Molecular techniques were used to identify the sex of taiko, which is difficult to assign morphologically. Blood samples were obtained from almost the entire known living population and from some birds now thought to be dead. We report an approximately even sex ratio in taiko chicks and adults associated with breeding burrows, but a large male-biased ratio in non-breeding adult birds caught on the ground. This finding suggests that unpaired males may be having difficulty in attracting females to burrows and that this situation may be an example of the Allee effect, that reduced density of potential mates acts to decrease population productivity. Identification of the sex of taiko using a molecular technique has important implications for the conservation management of this critically endangered species, including the future transfer of taiko chicks to a predator-excluded breeding site.     

Human and mouse mutations in WDR35 cause short-rib polydactyly syndromes due to abnormal ciliogenesis

Defects in cilia formation and function result in a range of human skeletal and visceral abnormalities. Mutations in several genes have been identified to cause a proportion of these disorders, some of which display genetic (locus) heterogeneity. Mouse models are valuable for dissecting the function of these genes, as well as for more detailed analysis of the underlying developmental defects. The short-rib polydactyly (SRP) group of disorders are among the most severe human phenotypes caused by cilia dysfunction. We mapped the disease locus from two siblings affected by a severe form of SRP to 2p24, where we identified an in-frame homozygous deletion of exon 5 in WDR35. We subsequently found compound heterozygous missense and nonsense mutations in WDR35 in an independent second case with a similar, severe SRP phenotype. In a mouse mutation screen for developmental phenotypes, we identified a mutation in Wdr35 as the cause of midgestation lethality, with abnormalities characteristic of defects in the Hedgehog signaling pathway. We show that endogenous WDR35 localizes to cilia and centrosomes throughout the developing embryo and that human and mouse fibroblasts lacking the protein fail to produce cilia. Through structural modeling, we show that WDR35 has strong homology to the COPI coatamers involved in vesicular trafficking and that human SRP mutations affect key structural elements in WDR35. Our report expands, and sheds new light on, the pathogenesis of the SRP spectrum of ciliopathies.