Single-atom nanozymes with axial ligand-induced self-adaptive conformation in alkaline medium boost chemiluminescence

Mimicking the structure of natural enzymes for designing advanced alternatives provides great opportunities to address the bottleneck of enzyme-involved chemiluminescence(CL). Herein, according to theoretical calculations, we found that an endogenous axial ligand of M-N-C single-atom nanozymes(SAzymes), originating from OH-spontaneously bonding to the metal center in an alkaline medium, can self-adaptively change its strength to facilitate intermediate steps. Furthermore, the lowest energy barrier of the rate-determining step and the strongest affinity and fastest electron transfer with luminol anion endow CoN-C with the highest peroxidase-like activity. Guided by the theoretical calculations, a series of M-N-C SAzymes(M=Fe, Co,Ni) were synthesized to boost CL, where Co-N-C SAzymes with superior catalytic activity and high selective generation of O_(2)·- were validated. As a proof-of-concept, Co-N-C SAzymes were employed for sensitive detection of acetylcholinesterase and organophosphorus pesticide.

Surrogate production of genome-edited sperm from a different subfamily by spermatogonial stem cell transplantation

The surrogate reproduction technique,such as inter-specific spermatogonial stem cells(SSCs)transplantation(SSCT),provides a powerful tool for production of gametes derived from endangered species or those with desirable traits.However,generation of genome-edited gametes from a different species or production of gametes from a phylogenetically distant species such as from a different subfamily,by SSCT,has not succeeded.Here,using two small cyprinid fishes from different subfamilies,Chinese rare minnow(gobiocypris rarus,for brief:Gr)and zebrafish(danio rerio),we successfully obtained Gr-derived genome-edited sperm in zebrafish by an optimized SSCT procedure.The transplanted Gr SSCs supported the host gonadal development and underwent normal spermatogenesis,resulting in a reconstructed fertile testis containing Gr spermatids and zebrafish testicular somatic cells.Interestingly,the surrogate spermatozoa resembled those of host zebrafish but not donor Gr in morphology and swimming behavior.When pou5f3 and chd knockout Gr SSCs were transplanted,Gr-derived genome-edited sperm was successfully produced in zebrafish.This is the first report demonstrating surrogate production of gametes from a different subfamily by SSCT,and surrogate production of genome-edited gametes from another species as well.This method is feasible to be applied to future breeding of commercial fish and livestock.

Cilia regulate meiotic recombination in zebrafish

Meiosis is essential for evolution and genetic diversity in almost all sexual eukaryotic organisms.The mechanisms of meiotic recombination,such as synapsis,have been extensively investigated.However,it is still unclear whether signals from the cytoplasm or even from outside of the cell can regulate the meiosis process.Cilia are microtubule-based structures that protrude from the cell surface and function as signaling hubs to sense extracellular signals.Here,we reported an unexpected and critical role of cilia during meiotic recombination.During gametogenesis of zebrafish,cilia were specifically present in the prophase stages of both primary spermatocytes and primary oocytes.By developing a germ cell-specific CRISPR/Cas9 system,we demonstrated that germ cell-specific depletion of ciliary genes resulted in compromised double-strand break repair,reduced crossover formation,and increased germ cell apoptosis.Our study reveals a previously undiscovered role for cilia during meiosis and suggests that extracellular signals may regulate meiotic recombination via this particular organelle.