Distribution of growth hormone-like immunoreactive cells and somatostatin receptors in the nervous system and Hatschek's pit of amphioxus, Branchiostoma belcheri

Using immunohistochemical method and double staining technique, the localization of growth hormone (GH) and somatostatin receptors in the nervous system and Hatschek's pit of amphioxus has been investigated. The results showed that the growth hormone-like nerve cells and endocrine cells as well as three subtypes of somatostatin receptors exist in the nervous system and Hatschek's pit, and GH-like nerve cells and endocrine cells co-exist with three subtypes of somatostatin receptors in the brain vesicle and Hatschek's pit. It is suggested that a primitive control system of inhibitory growth hormone secretion in Hatschek's pit could have been developed in amphioxus, as in vertebrates. The present study provides new evidence for the endocrinology and the evolution of Hatschek's pit.     

Distribution of growth hormone-like immunoreactive cells and somatostatin receptors in the nervous system and Hatschek''s pit of amphioxus, Branchiostoma belcheri

Using immunohistochemical method and double staining technique, the localization of growth hormone (GH) and somatostatin receptors in the nervous system and Hatschek's pit of amphioxus has been investigated. The results showed that the growth hormone-like nerve cells and endocrine cells as well as three subtypes of somatostatin receptors exist in the nervous system and Hatschek's pit, and GH-like nerve cells and endocrine cells co-exist with three subtypes of somatostatin receptors in the brain vesicle and Hatschek's pit. It is suggested that a primitive control system of inhibitory growth hormone secretion in Hatschek's pit could have been developed in amphioxus, as in vertebrates. The present study provides new evidence for the endocrinology and the evolution of Hatschek's pit.     

Distribution of growth hormone-like immunoreactive cells and somatostatin receptors in the nervous system and Hatschek''''s pit of amphioxus, Branchiostoma belcheri

Using immunohistochemical method and double staining technique, the localization of growth hormone (GH) and somatostatin receptors in the nervous system and Hatschek's pit of amphioxus has been investigated. The results showed that the growth hormone-like nerve cells and endocrine cells as well as three subtypes of somatostatin receptors exist in the nervous system and Hatschek s pit, and GH-like nerve cells and endocrine cells co-exist with three subtypes of somatostatin receptors in the brain vesicle and Hatschek s pit. It is suggested that a primitive control system of inhibitory growth hormone secretion in Hatschek s pit could have been developed in amphioxus, as in vertebrates. The present study provides new evidence for the endocrinology and the evolution of Hatschek's pit.     

Chemical Structure and Biological Activity of Humic Substances Define Their Role as Plant Growth Promoters

Humic substances (HS) are dominant components of soil organic matter and are recognized as natural, effective growth promoters to be used in sustainable agriculture. In recent years, many efforts have been made to get insights on the relationship between HS chemical structure and their biological activity in plants using combinatory approaches. Relevant results highlight the existence of key functional groups in HS that might trigger positive local and systemic physiological responses via a complex network of hormone-like signaling pathways. The biological activity of HS finely relies on their dosage, origin, molecular size, degree of hydrophobicity and aromaticity, and spatial distribution of hydrophilic and hydrophobic domains. The molecular size of HS also impacts their mode of action in plants, as low molecular size HS can enter the root cells and directly elicit intracellular signals, while high molecular size HS bind to external cell receptors to induce molecular responses. Main targets of HS in plants are nutrient transporters, plasma membrane H⁺-ATPases, hormone routes, genes/enzymes involved in nitrogen assimilation, cell division, and development. This review aims to give a detailed survey of the mechanisms associated to the growth regulatory functions of HS in view of their use in sustainable technologies.