The Characteristics and Expression Profile of Transferrin in the Accessory Nidamental Gland of the Bigfin Reef Squid during Bacteria Transmission

Abstract

The accessory nidamental gland (ANG) is a female reproductive organ found in most squid and cuttlefish that contains a consortium of bacteria. These symbiotic bacteria are transmitted from the marine environment and selected by the host through an unknown mechanism. In animals, a common antimicrobial mechanism of innate immunity is iron sequestration, which is based on the development of transferrin (TF)-like proteins. To understand this mechanism of host-microbe interaction, we attempted to characterize the role of transferrin in bigfin reef squid (Sepioteuthis lessoniana) during bacterial transmission. qPCR analysis showed that Tf was exclusively expressed in the outer layer of ANG,and this was confirmed by in situ hybridization, which showed that Tf was localized in the outer epithelial cell layer of the ANG. Western blot analysis indicated that TF is a soluble glycoprotein. Immunohistochemical staining also showed that TF is localized in the outer epithelial cell layer of the ANG and that it is mainly expressed in the outer layer during ANG growth. These results suggest that robust Tf mRNA and TF protein expression in the outer layer of the ANG plays an important role in microbe selection by the host during bacterial transmission.

Bacterial Dynamics in the Accessory Nidamental Gland of <i>Sepioteuthis lessoniana</i> throughout Maturation

“…In the case of S. lessoniana, this may be the result of host selection. Li et al (2019) indicated that the TF-like protein in the outer layer of the ANG played an important role in the selection of bacteria that are invaginated into the ANG of S. lessoniana. Even though the TF-like protein and lactotransferrin (LTF) may have antimicrobial functions in the host, both are considered to be essential for iron acquisition in Gram-negative bacteria.…”

“…Female S. lessoniana also have an ANG; however, information on the microbial community associated with this ANG is limited. Li et al (2019) hypothesized that as bacteria move from marine environments into the ANG, the transferrin (TF)-like protein of the host may play an essential role in microbial selection. During the maturation process, the ANG gradually transfers bacteria from the outer epithelial cell layer, invaginating bacteria into the ANG and forming tubule structures for bacterial colonies ( Li et al , 2019 ).…”

Decreased ferroportin in hepatocytes promotes macrophages polarize towards an M2-like phenotype and liver fibrosis

“…Immunohistochemical analysis was played according to the procedure reported by Hau-Wen Li 39 . Deparaffinization of the tissue sections was executed using a graded ethanol series, and then 0.3% hydrogen peroxide was used to block endogenous peroxidase activity.…”

Decreased Ferroportin in Hepatocytes Promotes Macrophages Polarize Towards an M2-Like Phenotype and Liver Fibrosis

“…Immunohistochemical analysis. Immunohistochemical analysis was played according to the procedure reported by Hau-Wen Li 35 . Depara nization of the tissue sections was executed using a graded ethanol series, and then 0.3% hydrogen peroxide was used to block endogenous peroxidase activity.…”