Preliminary Study On Tooth Morphology Structure,and Early Development Of Siniperca Chuatsi

Teeth are important feeding organs for carnivorous fishes.Siniperca chuatsi is a carnivorous fish with large crack and well-developed teeth that help it grasp food,prevent prey from escaping and improve its hunting efficiency.In this paper,the distribution,morphology and number of teeth of S.chuatsi,were observed by anatomical microscope.The tooth structure,elemental composition and chemical composition were observed and detected by alizarin red staining,tissue section,scanning electron microscope,X-ray energy spectrum and infrared spectroscopy.The development time,number and column number of the teeth at the early stage of S.chuatsi were observed by anatomical microscope and tissue section,the mineralization time of the teeth was also observed by cartilaginous bone staining and Von kossa staining,and the expression of alkaline phosphatase during tooth mineralization was observed by immunohistochemistry.The relative gene expression levels of cellular junction gap protein 43 and calcium-binding protein d28 k were observed by fluorescence quantitative PCR during tooth mineralization,which provide some basic data for the study of tooth morphology,structure and development.The results are as follows:(1)In order to understand the morphology and structure of tooth of Siniperca chuatsi,the distribution,morphology and number of tooth of S.chuatsi were observed by anatomical microscope.The tooth structure,elemental composition and chemical composition of S.chuatsi were observed and detected by alizarin red staining,tissue section,scanning electron microscope,X-ray energy spectrum and infrared spectroscopy.The results show that the tooth of S.chuatsi have maxillary tooth,mandibular tooth,vomerine tooth,palatal tooth and pharyngeal tooth.Among them,canine tooth were detected in front of maxillary tooth and the inner line of mandibular tooth,the rest are villous tooth.The tooth of the vomerine,the palate and the pharynx are all villous.Both canine and villous tooth have transparent enamel on the outer layer and dentin on the inner layer surrounding the medullary cavity.Dentin structure is loose with pores;the tip of the tooth forms the enamel cap;The central pulp cavity contains pulp tissue.The surfaces of canine and villous teeth are composed of glazed columns.The main elements of canine teeth and villous tooth are carbon(C),oxygen(O),nitrogen(N),calcium(Ca)and phosphorus(P),and the main inorganic components of canine tooth and villous tooth are carbonate hydroxyapatite.The results show that S.chuatsi has more advanced tooth with canines in maxillary and mandibular tooth.The canine tooth and villous tooth have similar structure and chemical composition,which help S.chuatsi to hunt and swallow live bait.(2)In order to understand the tooth development and mineralization process of S.chuatsi,the changes of tooth occurrence time,number and column number of 1-55 days fishes were observed by anatomical microscope and tissue section.The tooth mineralization time was observed by cartilaginous bone staining and von kossa staining.Elemental changes during tooth mineralization were determined by X-ray energy spectrometry.The expression of alkaline phosphatase during tooth mineralization was observed by immunohistochemistry,and the relative expression levels of cell junction gap protein 43 and calcium-binding protein d28 k in the tooth mineralization process were observed by fluorescence quantitative PCR experiments.The results showed that the maxillary tooth and mandibular tooth of S.chuatsi appeared at 3d,the pharyngeal tooth appeared at 5d,the palate tooth appeared at 8d and the vomerine tooth appeared at 12 d.The mandibular dentition were fully developed at 8d,while maxillary dentition at 11 d.In the maxillary and mandibular tooth,villous tooth developed firstly,canine tooth began to develop at 18 days,and there was a marked difference in size between canine tooth and villous tooth at 30 days.Maxillary tooth,mandibular tooth,palatal tooth and pharyngeal tooth began to be mineralized at 11 d,basically mineralized at 12 d,and completely mineralized at 14 d.The vomerine tooth strarted mineralization at 12 d,basic mineralization at 13 d,and complete mineralization at 14 d.During the tooth mineralization,the contents of Ca and P increase significantly,but the Ca/P ratio has no significant difference.The alkaline phosphatase showed positive reaction in the enamel and dentin at 10 d and 12 d,and the cell junction gap protein 43 and calcium-binding protein d28 k increased significantly at 12 d and decreased significantly at 14 d.The results showed that the maxillary tooth,mandibular tooth,palatal tooth,pharyngeal tooth and vomerine tooth of S.chuatsi all appeared at 12 d and were completely mineralized at 14 d,which is helpful to the early feeding.