Ecchordosis physaliphora and its variants: proposed new classification based on high-resolution fast MR imaging employing steady-state acquisition.

OBJECTIVES: To propose a new classification for ecchordosis physaliphora (EP) using fast imaging employing steady-state acquisition (FIESTA). METHODS: We evaluated 974 consecutive patients and selected for further study 78 (8.0 %) who manifested an excrescence on the dorsal surface of the clivus (DSC) and/or clivus lesions. Lesions were defined as "classical EP" when they appeared as a hyperintense excrescence (cyst-like component) on DSC. Other lesions were defined as "possible EP". RESULTS: Of the 78 patients, 17 (22 %) were diagnosed with classical EP, the other 61 with possible EP. The 61 patients with possible EP were further classified into "incomplete EP = EP bud" (n = 55, 90.2 %), characterised by a T2 hypointense protrusion of the clivus, and into "EP variant" (n = 6, 9.8 %), characterised by hyperintense lesions within only clivus. FIESTA findings of incomplete EP were similar to those of classical EP except for lack of the hyperintense excrescence on DSC. Most lesions were located at the level of the Dorello canal at the midline of the craniospinal axis. CONCLUSION: Our results suggest that the magnetic resonance imaging appearance of EP is diverse. Based on our FIESTA results we propose a new classification for EP, i.e. classical EP, incomplete EP (EP bud) and EP variant. KEY POINTS: • Ecchordosis physaliphora (EP) is a rare benign cystic congenital lesion arising from notochord. • The classical type of EP is frequently associated with a T2 hypointense protrusion. • T2 hypointense protrusions without clivus cysts may represent an incomplete type of EP. • Third type of EP variant only harbours lesions within the clivus.

Identification of proteins and developmental expression of RNAs encoded by the 65A cuticle protein gene cluster in Drosophila melanogaster.

Proteins of the third instar larval cuticle of Drosophila melanogaster, LCP5-LCP9, were purified and their N-terminal sequences determined. Three of these proteins (LCP5, 6, and 8) were found to be encoded by two multicopy genes previously mapped to the gene cluster at 65A 5-6 on the left arm of the third chromosome. The analysis of the patterns of developmental expression of the 8 distinct genes at this site showed that all but two were expressed during larval life. The patterns fell into three groups: one where expression was all through larval life, one where expression was primarily in the third instar, and one only during the production of the adult cuticle. One duplicated gene was not expressed in the Canton S strain at any time from the embryo to adult ecdysis. These findings indicate that there is not a unique set of cuticle proteins in the third versus the first and second instar larval cuticles and indicates that overlapping gene sets in several different gene clusters encode the proteins of the cuticle of different developmental stages.

Sequence, structure and evolution of the ecdysone-inducible Lsp-2 gene of Drosophila melanogaster.

The Lsp-2 gene encodes a major larval serum protein (hexamerin) of Drosophila melanogaster. Transcription of Lsp-2 is controlled by 20-hydroxyecdysone. Here we report the analysis of the structure of the Lsp-2 gene including the adjacent 5' and 3' sequences. In contrast to all other known hexamerin genes, Lsp-2 does not contain an intron. The Lsp-2 mRNA measures 2312 bases, as deduced from experimental determination of the transcription-start and stop sites and conceptual translation results in a 718 amino acid hexamerin subunit, including a 21-amino-acid signal peptide. While the calculated molecular mass of the native 697-amino-acid subunit is 83.5 kDa, mass spectrometry gave a value of 74.5 kDa. We detected in the Lsp-2 gene a 2052-bp antisense ORF that probably does not code for any protein. An unusual accumulation of rarely used codon triplets was found at the 5' and 3' ends of the Lsp-2 ORF. The calculated secondary structure matches well with that of arthropod hemocyanins. Electron micrographs show for LSP-2 hexamers a cubic shape, which can not be easily reconciled with its hexameric structure. Phylogenetic analysis revealed that LSP-2 diverged from the LSP-1 like hexamerins after separation of the Diptera from other insect orders.

A cluster of cuticle protein genes of Drosophila melanogaster at 65A: sequence, structure and evolution.

A 36-kb genomic DNA segment of the Drosophila melanogaster genome containing 12 clustered cuticle genes has been mapped and partially sequenced. The cluster maps at 65A 5-6 on the left arm of the third chromosome, in agreement with the previously determined location of a putative cluster encompassing the genes for the third instar larval cuticle proteins LCP5, LCP6 and LCP8. This cluster is the largest cuticle gene cluster discovered to date and shows a number of surprising features that explain in part the genetic complexity of the LCP5, LCP6 and LCP8 loci. The genes encoding LCP5 and LCP8 are multiple copy genes and the presence of extensive similarity in their coding regions gives the first evidence for gene conversion in cuticle genes. In addition, five genes in the cluster are intronless. Four of these five have arisen by retroposition. The other genes in the cluster have a single intron located at an unusual location for insect cuticle genes.

Denaturation and renaturation of a beta-1,6;1,3-glucan, lentinan, associated with expression of T-cell-mediated responses.

Correlation between the higher structure and biological functions of lentinan, a beta-1,6;1,3-glucan capable of potentiating T- and non-T-cell-mediated responses, were investigated by measurements of optical rotation and some biological responses. The addition of urea or dimethyl sulfoxide decreased specific rotation at 589 nm, [alpha]D, of lentinan in a concentration-dependent manner and the removal of these denaturants resulted in the recovery of [alpha]D values. Measurements of optical rotatory dispersion in the spectral region between 600 and 200 nm showed the change in the higher structure of lentinan more clearly. Denaturation and renaturation of lentinan using urea and dimethyl sulfoxide were associated with the decrease and the recovery of antitumor activity against P-815 mastocytoma and vascular dilation and hemorrhage-inducing activity, found to be T-cell-mediated responses. Lentinan was also denatured by NaOH and the transition of [alpha]D values and optical rotatory dispersion curves were seen in the manner of two concentration-dependent phases. Removal of NaOH led to the recovery of optical rotation of lentinan and its antitumor and vascular dilation and hemorrhage-inducing activity. However, recovery of these bioactivities was more difficult in the case of the higher concentrations of NaOH above 2% than the lower ones. During the process of renaturation of lentinan, random aggregation may take place. An increase of serum acute phase proteins, a non-T-cell-mediated response caused by lentinan, was not affected by the change of the higher structure of lentinan.

The cuticle proteins of Drosophila melanogaster: genetic localization of a second cluster of third-instar genes.

Five third-instar larval cuticle protein genes are placed on the left arm of the third chromosome. For these five genes, 12 variants and two induced mutants are described. All the naturally occurring variants are codominant. One EMS-induced mutant is characterized by the codominant appearance of a new protein, and a second by a recessive mutation that codes for a modifier of third-instar larval cuticle protein 5 (L3CP-5). All but the putative modifier gene map to within less than 0.3 map units of each other on the left arm of the third chromosome at approximately 11. We propose that these genes constitute a cluster of third-instar cuticle protein genes. The induced recessive mutant maps outside of the cluster to a region also on the left arm of the third chromosome. The proteins and their genes should prove useful for both developmental and evolutionary studies.