ABSTRACT
It is well established that the targeted receptor for ciguatoxin (CTX) in mammalian tissues is the sodium channel, affecting the influx of sodium into cells and altering the action potential and function of the cell. Since the syntheses of fragments of CTX has become available, our focus has been on the receptor functions of the west sphere AB and east sphere JKLM fragments using the neuroblastoma cell assay, guinea pig atrium assay, and the membrane immunobead assay (MIA). The data presented here suggest that the west sphere AB of the ciguatoxin molecule is the active portion and is responsible for the activation of the sodium channels.
Subject(s)
Ciguatoxins/pharmacology , Neurons/drug effects , Sodium Channels/drug effects , Animals , Cell Line, Tumor , Ciguatoxins/antagonists & inhibitors , Ciguatoxins/chemistry , Epitopes , Guinea Pigs , Heart Atria/drug effects , Heart Atria/physiopathology , Male , Mice , Myocardial Contraction/drug effects , Myocardial Contraction/physiology , Neuroblastoma/metabolism , Neuroblastoma/pathology , Neurons/metabolism , Neurons/pathology , Seafood/analysis , Sodium Channels/metabolism , Structure-Activity Relationship , SwineABSTRACT
The fabA gene of Escherichia coli encodes beta-hydroxydecanoyl thioester dehydrase (HDDase), a pivotal enzyme in the biosynthesis of the unsaturated fatty acid cis-vaccenic acid, through the anaerobic pathway. This enzyme is specific to bacterial fatty acid biosynthetic pathways, although other enzymes for fatty acid synthesis are very similar in plants and bacteria. We constructed chimaeric plant expression vectors, pfab21 and pfab22, carrying the fabA gene under the transcriptional control of the cauliflower mosaic virus (CaMV) promoter of 35S RNA. In pfab21, fabA was placed directly under the control of the CaMV 35S promoter; whereas in pfab22, the DNA sequence coding for the chloroplast-targeting transit peptide (TP) of the pea ribulose-1,5-bisphosphate carboxylase (RuBisCo) small subunit was fused to the fabA gene in order to allow transport of HDDase to the chloroplast, the organelle responsible for de novo fatty acid biosynthesis in plants. Transgenic plants of Nicotiana tabacum were obtained by Agrobacterium-mediated transformation with pfab21 or pfab22. Expression of fabA transcripts of sizes expected from the chimaeric constructs was shown by RNA blot hybridization. The HDDase protein derived from pfab22 was correctly processed and transported to chloroplasts in transformed plants. The enzymatic activity of HDDase was also detected in chloroplasts isolated from the transformants derived from pfab22 (but not pfab21) and in total leaf protein of all transformants. However, no significant changes were observed in the fatty acid compositions, including cis-vaccenic acid, of leaf chloroplasts and self-fertilized seeds. These results are discussed in relation with the possible structural organization of plant fatty acid synthase.
Subject(s)
Chloroplasts/metabolism , Escherichia coli/genetics , Hydro-Lyases/genetics , Nicotiana/genetics , Plants, Toxic , Base Sequence , Biological Transport , DNA Primers , Escherichia coli/enzymology , Fatty Acid Synthase, Type II , Fatty Acids/analysis , Genes, Bacterial , Genetic Vectors , Hydro-Lyases/metabolism , Molecular Sequence Data , Plants, Genetically Modified/chemistry , RNA, Messenger/genetics , Nicotiana/chemistry , Nicotiana/metabolism , Transformation, GeneticABSTRACT
Craniofacial surgery for craniosynostosis is now often performed, and many cases have been reported. Twinning among these cases is of particular interest. An extremely rare case of cranial reshaping of concordant dizygotic twins with trigonocephaly is described in this report.
Subject(s)
Craniosynostoses/surgery , Diseases in Twins , Frontal Bone/surgery , Female , Frontal Bone/abnormalities , Humans , Infant, Newborn , Male , Surgery, Plastic/methods , Twins, DizygoticABSTRACT
Analysis of foot pressures in cases of reconstructed adactyly of the lateral toes is presented. Two cases with adactyly of the 4th and 5th toes in which new toes were created by cross-knee tubed pedicle flap were chosen and foot pressures of both the operated foot and the contralateral normal foot were measured postoperatively. The results did not indicate any functional disturbance after this method of reconstruction.