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Biomedical subjects

E A Burgess

Publications and source records attributed to E A Burgess.

At least 19 recordsLinked to original sources
PubMed1998

Control of distal antennal identity and tarsal development in Drosophila by spineless-aristapedia, a homolog of the mammalian dioxin receptor.

We report the molecular characterization of the spineless (ss) gene of Drosophila, and present evidence that it plays a central role in defining the distal regions of both the antenna and leg. ss encodes the closest known homolog of the mammalian dioxin receptor, a transcription factor of the bHLH-PAS family. Loss-of-function alleles of ss cause three major phenotypes: transformation of distal antenna to leg, deletion of distal leg (tarsal) structures, and reduction in size of most bristles. Consistent with these phenotypes, ss is expressed in the distal portion of the antennal imaginal disc, the tarsal region of each leg disc, and in bristle precursor cells. Ectopic expression of ss causes transformation of the maxillary palp and distal leg to distal antenna, and induces formation of an ectopic antenna in the rostral membrane. These effects indicate that ss plays a primary role in specifying distal antennal identity. In the tarsus, ss is expressed only early, and is required for later expression of the tarsal gene bric à brac (bab). Ectopic expression causes the deletion of medial leg structures, suggesting that ss plays an instructive role in the establishment of the tarsal primordium. In both the antenna and leg, ss expression is shown to depend on Distal-less (Dll), a master regulator of ventral appendage formation. The antennal transformation and tarsal deletions caused by ss loss-of-function mutations are probably atavistic, suggesting that ss played a central role in the evolution of distal structures in arthropod limbs.

Alleles↗
PubMed1990

Direct control of antennal identity by the spineless-aristapedia gene of Drosophila.

Loss-of-function mutations in the spineless-aristapedia gene of Drosophila (ssa mutants) cause transformations of the distal antenna to distal second leg, deletions or fusions of the tarsi from all three legs, a general reduction in bristle size, and sterility. Because ssa mutants are pleiotropic, it has been suggested that ss+ has some rather general function and that the ssa antennal transformation is an indirect consequence of perturbations in the expression of other genes that more directly control antennal or second leg identity. Here we test whether the ssa transformation results from aberrant expression of Antennapedia (Antp), a homeotic gene thought to specify directly the identity of the second thoracic segment. We find that Antp-ssa mitotic recombination clones in the distal antenna behave identically to Antp+ ssa clones, and are transformed to second leg. This demonstrates that the ssa antennal transformation is independent of Antp+, and suggests that ss+ may itself directly define distal antennal identity. The results also reveal that Antp+ is not required for the development of distal second leg structures, as these develop apparently normally in Antp- ssa antennal clones. Because Antp- mutations cause deletions or transformations that are restricted to proximal structures, whereas ssa alleles cause similar defects that are distally restricted, we suggest that ss+ and Antp+ may play similar, but complementary, roles in the distal and proximal portions of appendages, respectively.

Alleles↗
PubMed1984

Inducibility of heat shock polypeptides in cells containing hyperacetylated histones.

We have examined the effect of sodium butyrate on the levels of histone acetylation, the pattern of protein synthesis and the inducibility of heat shock polypeptides (hsps) in cultured trout fibroblasts. Maximal levels of histone acetylation are achieved upon treatment of these cells with 5 mM butyrate for 24 h. No significant changes in the pattern of protein synthesis, as detected by two-dimensional gel electrophoresis, are apparent under these conditions, although changes in the levels of three polypeptides are seen at shorter times of exposure to butyrate. Heat shock polypeptides are inducible at normal levels in butyrate-treated cells. This is in contrast to the ability of butyrate to inhibit the activation of steroid-inducible genes in some systems.

Acetylation↗
PubMed1980

Three instances of neonatal death with hyperammonaemia, each resulting from a different cause.

We report here the results of a study of three unrelated patients, K., M. and R., each of whom died in the neonatal period in St Sophia's Children's Hospital, Athens, Greece, after a normal pregnancy and delivery. Liver functions tests and blood cultures gave normal results in each case and autopsy did not reveal any specific findings. All had gross hyperammonaemia and were considered to have possible urea cycle defects.

Amino Acids↗
PubMed1978

Acute neonatal and benign citrullinaemia in one sibship.

Citrullinaemia was diagnosed in an infant who died at age 8 days. The clinical picture was of the disease in its acute neonatal form. A sib has a blood citrulline of 100 times normal and about 10% of normal argininosuccinic acid synthetase activity in cultured fibroblasts. Clinically he is normal with an IQ of 94 on the Wechsler Intelligence Scale for Children.

Amino Acid Metabolism, Inborn Errors↗
PubMed1978

Neonatal hyperammonaemia with complete absence of liver carbamyl phosphate synthetase activity.

Two newborn infants, male (A) and female (B), with lethal hyperammonaemia are described in the same family. In both, symptoms started on the second day of life. Lethargy and hypotonia were the most prominent initial findings and were followed by convulsions and coma. In both, blood ammonia levels rose to 570 mumol/u (795 microgram/100 ml) a few hours before death, which occurred on the third and fourth day of life respectively. Assay of liver urea cycle enzymes in baby B showed a complete absence of mitochondrial carbamyl phosphate synthetase activity.

Amino Acid Metabolism, Inborn Errors↗
PubMed1978

Sucrase-isomaltase deficiency. A follow-up report.

Nine children with sucrase-isomaltase deficiency were assessed up to 10 years after diagnosis. All children continued to have episodes of diarrhoea associated with sucrose ingestion. Sucrose tolerance tests showed that malabsorption of sucrose persists into adolescence. Three older patients were unaware of their condition and were eating normal diets with unrestricted amounts of sucrose. They complained of gastrointestinal symptoms which improved after sucrose restriction.

Child, Preschool↗