Development and growth of organs in living whole embryo and larval grafts in zebrafish

Abstract

Age-related systemic environments influence neurogenesis and organ regeneration of heterochronic parabiotic partners; however, the difficulty of manipulating small embryos prevents the effects of aged systemic environments on primitive organs at the developmental stage from being analysed. Here, we describe a novel transplantation system to support whole living embryos/larvae as grafts in immunodeficient zebrafish by the intrusion of host blood vessels into the grafts, allowing bodies similar to those of heterochronic parabiosis to be generated by subcutaneous grafting. Although grafted embryos/larvae formed most organs, not all organogenesis was supported equally; although the brain, eyes and the intestine usually developed, the liver, testes and heart developed insufficiently or even occasionally disappeared. Removal of host germ cells stimulated testis development in grafted embryos. These results indicate that primitive testes are susceptible to the systemic environments that originated from the germ cells of aged hosts and imply that the primitive liver and heart are similar. Upon applying this method to embryonic lethal mutants, various types of organs, including testes that developed in germ-cell-removed recipients, and viable offspring were obtained from the mutants. This unique transplantation system will lead to new insights into the age-related systemic environments that are crucial for organogenesis in vertebrates.

Embryonic and early larval development of Florida pompano, Trachinotus carolinus

“…In the present study, the embryonic pronephros of larval Florida pompano developed into the larval kidney during the first 7 dph. Mesonephric tubules and glomeruli increased in number, and interspersed hematopoietic islands Boglione et al, 1995;Crespo et al, 2001;Dias et al, 2022;Giménez & Estévez, 2008;Kawasaki et al, 2017;Koumoundouros et al, 2004;Nowak & Battaglene, 1996;Peruzzi et al, 2004;Sivaloganathan et al, 1996). The causes and effects of cystic calculi in these species remain unclear, but both environmental (salinity and temperature) and nutritional (dietary mineral and taurine) factors have been shown to play a role (Dias et al, 2022).…”

“…Interestingly, by ~96 hpf (3 dph) and 1 day after enriched rotifer feeding initiation, cystic calculi were visible in the early urinary bladder of many observed pompano larvae. Cystic calculi have been noted in other marine teleost larvae reared in aquaculture including sea bass, Dicentrarchus labrax , brown‐marbled grouper, Epinephelus fuscoguttatus , Japanese flounder, Paralichthys olivaceus , common dentex, Dentex dentex , gilthead sea bream, Sparus aurata , snapper, Pagrus auratus , mulloway, Argyrosomus hololepidotus , Australian bass, Macquaria novemaculeata , and striped trumpeter, Latris lineata (Allon et al, 2016; Boglione et al, 1995; Crespo et al, 2001; Dias et al, 2022; Giménez & Estévez, 2008; Kawasaki et al, 2017; Koumoundouros et al, 2004; Nowak & Battaglene, 1996; Peruzzi et al, 2004; Sivaloganathan et al, 1996). The causes and effects of cystic calculi in these species remain unclear, but both environmental (salinity and temperature) and nutritional (dietary mineral and taurine) factors have been shown to play a role (Dias et al, 2022).…”

Robust and local positional information within a fin ray directs fin length during zebrafish regeneration

“…Therefore, we performed fin ray grafting using the rag1 line, a zebrafish mutant that lacks immune B and T cells, as a host (Figure 5a). Studies have shown that grafted testis and whole embryos are maintained for a long time using the rag1 mutant line (Kawasaki, Maeno, Shiroishi, & Sakai, 2017;Kawasaki, Siegfried, & Sakai, 2016). First, we tested the ability of fins to regenerate in the rag1 homozygous mutant line and observed that the rag1 mutant line normally regenerates the fin (Figure 5b), indicating that humoral immunity is not critical for normal fin regeneration.…”

Embryonic Onset of Sexually Dimorphic Heart Rates in the Viviparous Fish, Gambusia holbrooki

“…Of the Poeciliids, G. holbrooki and G. affinis are the best examples of adaptation and survival under extreme environmental conditions [ 21 ] and are currently considered highly invasive species worldwide [ 22 ]. Such adaptive ability demands functional plasticity in organ development and their performance, with the heart the most critical for survival [ 23 ]. Studies in even the less hardy Poeciliids such as guppy, Poecilia reticulata , and Amazon molly, Poecilia formosa , have shown that they are less prone to heart diseases [ 17 , 24 ].…”

“…For example, in embryonic zebrafish migration of primordial germ cells (PGCs) towards the putative gonadal ridge coincides with heart formation by 24 h post-fertilisation [ 35 ]. Moreover, a recent study indicated that there is a relation between primitive testis development with that of heart and liver in embryonic zebrafish [ 23 ], suggesting that many aspects of organogenesis are closely related and those obviously may thus bear witness to more cryptic sex differentiation events that occur in parallel.…”