[Hallucinations. Diagnostic orientation].
Explore the source record for details and available documents.
Hallucinations↗
Biomedical subjects
A Pham
Publications and source records attributed to A Pham.
The Suppressor of fused gene encodes a novel PEST protein involved in Drosophila segment polarity establishment.
Suppressor of fused, Su(fu), was identified as a semi-dominant suppressor of the putative serine/threonine kinase encoded by the segment polarity gene fused in Drosophila melanogaster. The amorphic Su(fu) mutation is viable, shows a maternal effect and displays no phenotype by itself. Su(fu) mutations are often found associated to karmoisin (kar) mutations but two complementation groups can be clearly identified. By using a differential hybridization screening method, we have cloned the Su(fu) region and identified chromosomal rearrangements associated with Su(fu) mutations. Two classes of cDNAs with similar developmental patterns, including a maternal contribution, are detectable in the region. Transformation experiments clearly assigned the Su(fu)+ function to one of these transcription units while the other one can be most likely assigned to the kar+ function. Surprisingly the 5' end of the kar RNA mapped within the 3' untranslated region of the Su(fu) transcribed sequence. The Su(fu) gene encodes a 53-kD protein, which contains a PEST sequence and shows no significant homologies with known proteins. Genetic analysis shows that proper development requires a fine tuning of the genetic doses of fu and Su(fu) both maternally and zygotically. These results, together with previous genetic and molecular data, suggest that fused and Suppressor of fused could act through a competitive posttraductionnal modification of a common target in the hedgehog signaling pathway.
Amino Acid Sequence↗
Segmental polarity in Drosophila melanogaster: genetic dissection of fused in a Suppressor of fused background reveals interaction with costal-2.
fused (fu) is a segment polarity gene that encodes a putative serine/threonine kinase. A complete suppressor of the embryonic and adult phenotypes of fu mutants, Suppressor of fused (Su(fu)), was previously described. The amorphic Su(fu) mutation is viable and displays no phenotype by itself. We have used this suppressor as a tool to perform a genetic dissection of the fu gene. Analysis of the interaction between Su(fu) and 33 fu alleles shows that they belong to three different classes. Defects due to class I fu alleles are fully suppressed by Su(fu). Class II fu alleles lead to a new segment polarity phenotype in interaction with Su(fu). This phenotype corresponds to embryonic and adult anomalies similar to those displayed by the segment polarity mutant costal-2 (cos-2). Class II alleles are recessive to class I alleles in a fu[I]/fu[II];Su(fu)/Su(fu) combination. Class 0 alleles, like class I alleles, confer a normal segmentation phenotype in interaction with Su(fu). However class II alleles are dominant over class 0 alleles in a fu[0]/fu[II];Su(fu)/Su(fu) combination. Alleles of class I and II correspond to small molecular events, which may leave part of the Fu protein intact. On the contrary, class 0 alleles correspond to large deletions. Several class I and class II fu mutations have been mapped, and three mutant alleles were sequenced. These data suggest that class I mutations affect the catalytic domain of the putative Fu kinase and leave the carboxy terminal domain intact, whereas predicted class II proteins have an abnormal carboxy terminal domain. Su(fu) enhances the cos-2 phenotype and cos-2 mutations interact with fu in a way similar to Su(fu). All together these results suggest that a close relationship might exist between fu, Su(fu) and cos-2 throughout development. We thus propose a model where the Fu+ kinase is a posterior inhibitor of Costal-2+ while Su(fu)+ is an activator of Costal-2+. The expression pattern of wingless and engrailed in fu and fu;Su(fu) embryos is in accordance with this interpretation.
Alleles↗
Effect of type III group B streptococcal capsular polysaccharide on invasion of respiratory epithelial cells.
Group B streptococcal (GBS) capsular polysaccharide is an important virulence factor, and its role in invasion of cultured respiratory epithelial cells was investigated. A type III GBS clinical isolate, COH1, and asialo and unencapsulated isogenic transposon capsule mutants of it were compared in an in vitro invasion assay. The results demonstrated that capsule attenuated the invasion process. Invasion was not affected when the A549 epithelial cells were preincubated with purified type III GBS capsular polysaccharide. Polyclonal type III GBS capsule antibody inhibited invasion by COH1 but did not affect invasion by the capsule mutants. Serotypes Ia, Ib, Ia/c, II, and III all invaded respiratory epithelial cells but demonstrated some strain variation in magnitude of invasion. These observations led us to conclude that type III capsular polysaccharide was not essential for invasion of respiratory epithelial cells by GBS and that bacterial factors other than capsule were responsible for respiratory epithelial cell invasion.
Bacterial Toxins↗
[Baroreceptors capable of inducing the biosynthesis and release of prostaglandins (PG) and of modulating adrenergic neurotransmission in the myocardium].
In the isolated Rabbit heart, high pressure, on the one hand, inhibits the noradrenaline release, and on the other hand, induces both the biosynthesis and release of PGs(PGE2,PGF2 alpha) from the auricles and mainly from the right auricle i.e. where the sympathetic nerve endings are the most numerous. Therefore, high pressure, by a negative feedback process, plays a great part in moderating the adrenergic neurotransmission responsible for the hypertension. These effects result from a supplementary pressure which acts on the walls of coronary arteries and arterioles and modifies their distensibility. It thus appears that in the walls of arteries and arterioles there are baroreceptors which are sensitive to the pressure variations in order to regulate adrenergic neurotransmission, by means of a reflex path still unknown.
Animals↗