ABSTRACT
Sexually mature planarians produce sex-inducing substances that induce postembryonic development of hermaphroditic reproductive organs in asexual freshwater planarians. Although the sex-inducing substances may be useful for elucidating the mechanism underlying this reproductive switch, the available information is limited. The potency of sex-inducing activity is conserved, at least at the order level. Recently, we showed that the sex-inducing activity in the land planarian Bipalium nobile was much higher than that in freshwater planarians. In the present study, we performed bioassay-guided fractionation of the sex-inducing substances produced by B. nobile and propose that crucial sex-inducing activity that triggers complete sexualization for asexual worms of the freshwater planarian Dugesia ryukyuensis is produced by additive and/or synergetic effects of various sex-inducing substances involved in ovarian development. The current study provided an isolation scheme for the minimum-required combination of sex-inducing substances for producing crucial sex-inducing activity.
Subject(s)
Planarians , Animals , Biological Assay , Fresh Water , Plant Extracts , Reproduction, AsexualABSTRACT
Two mammalian monoamine oxidases (MAO), MAO-A and MAO-B, are similar in primary structures but have unique substrate/inhibitor selectivities. Carp (Cyprinus carpio) contains a MAO enzyme (C-MAO) with properties different from MAO-A and MAO-B. To determine the molecular characteristics of C-MAO and its phylogenetic relationship with other fish and mammalian MAOs, the primary structure of C-MAO was estimated. The putative C-MAO cDNA encodes 526 amino acids with 59.001 Da, and the deduced amino acid sequence showed as much as 68.9% homology with some mammalian MAO-A proteins, 69.8% homology with some mammalian MAO-B proteins, and as much as 92.4% homology with some fish MAOs. Comparison of two regions in the polypeptide sequence of C-MAO determining possible substrate/inhibitor preferences of MAO-A and MAO-B showed both 79.5% homologies.
Subject(s)
Carps , Monoamine Oxidase/genetics , Monoamine Oxidase/metabolism , Amino Acid Sequence , Animals , Base Sequence , Binding Sites , Carps/genetics , Cell Membrane/metabolism , Cloning, Molecular , Conserved Sequence , DNA, Complementary/genetics , Evolution, Molecular , Flavin-Adenine Dinucleotide/metabolism , Humans , Molecular Sequence Data , Monoamine Oxidase/chemistry , Monoamine Oxidase Inhibitors/pharmacology , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Regarding therapeutic hypothermia for human neonatal hyperthermic hypoxic-ischemic encephalopathy (HIE), we investigated the motor function of a neonatal hyperthermic HIE rat model, and also performed systemic hypothermia using the model. Forty-two neonatal Wistar rats at 7-days-old were used in this study. The left common carotid artery of 34 neonatal rats was ligated under isoflurane anesthesia. We also established a sham group (S group, n = 8). After 1-h recovery, all rats were exposed to 8% oxygen at an ambient temperature (T (a)) of 40 degrees C for 15 min. Following insult, 16 rats were placed in a chamber at a T (a) of 30 degrees C (H group) and the other 18 rats at a T (a) of 37 degrees C after arterial ligation (N group), and all rats in the S group were placed in a chamber at a T (a) of 37 degrees C for 12 h. A Rota-Rod test was performed involving all rats at 8 weeks old. The rod was rotated at 5, 5, and 7 rpm on three consecutive days, respectively. Rats in the N group stayed on the rotating rod for a significantly shorter period than those in S and H groups only on the second day of measurement. The width of the insulted hemisphere in N group rats was significantly smaller than those in S and H groups. There was no significant correlation between S and H groups regarding the motor function and anatomy. These results suggest that neonatal hyperthermic hypoxic-ischemic insult impairs the motor function, which may be rescued by systemic hypothermia after insult.
