Spirocycles by transfer
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Recommendations for mitochondria transfer and transplantation nomenclature and characterization
Intercellular mitochondria transfer is an evolutionarily conserved process in which one cell delivers some of their mitochondria to another cell in the absence of cell division. This process has diverse functions depending on the cell types involved and physiological or disease context. Although mitochondria transfer was first shown to provide metabolic support to acceptor cells, recent studies have revealed diverse functions of mitochondria transfer, including, but not limited to, the maintenance of mitochondria quality of the donor cell and the regulation of tissue homeostasis and remodelling. Many mitochondria-transfer mechanisms have been described using a variety of names, generating confusion about mitochondria transfer biology. Furthermore, several therapeutic approaches involving mitochondria-transfer biology have emerged, including mitochondria transplantation and cellular engineering using isolated mitochondria. In this Consensus Statement, we define relevant terminology and propose a nomenclature framework to describe mitochondria transfer and transplantation as a foundation for further development by the community as this dynamic field of research continues to evolve.
Two types of motifs enhance human recall and generalization of long sequences
Whether it is listening to a piece of music, learning a new language, or solving a mathematical equation, people often acquire abstract notions in the sense of motifs and variables—manifested in musical themes, grammatical categories, or mathematical symbols. How do we create abstract representations of sequences? Are these abstract representations useful for memory recall? In addition to learning transition probabilities, chunking, and tracking ordinal positions, we propose that humans also use abstractions to arrive at efficient representations of sequences. We propose and study two abstraction categories: projectional motifs and variable motifs. Projectional motifs find a common theme underlying distinct sequence instances. Variable motifs contain symbols representing sequence entities that can change. In two sequence recall experiments, we train participants to remember sequences with projectional and variable motifs, respectively, and examine whether motif training benefits the recall of novel sequences sharing the same motif. Our result suggests that training projectional and variables motifs improve transfer recall accuracy, relative to control groups. We show that a model that chunks sequences in an abstract motif space may learn and transfer more efficiently, compared to models that learn chunks or associations on a superficial level. Our study suggests that humans construct efficient sequential memory representations according to the two types of abstraction we propose, and creating these abstractions benefits learning and out-of-distribution generalization. Our study paves the way for a deeper understanding of human abstraction learning and generalization.
Ultrafast exciton-phonon coupling and energy transfer dynamics in quasi-2D layered Ruddlesden-Popper perovskites
Understanding the performance of perovskite solar cells is critical for advancing sustainable energy solutions. Hot-drop casted quasi-2D Ruddlesden-Popper perovskites (RPPs) exhibit remarkable efficiency and stability, making them promising for commercial applications. However, the ultrafast energy transfer and exciton-phonon interactions in these materials remain unclear. Here, we show that using advanced techniques like two-dimensional electronic spectroscopy (2DES) and transient grating (TG), we can unravel energy dynamics in hot-drop casted RPP films. Our study reveals rapid energy transfer between perovskite layers occurring within 100–220 femtoseconds and highlights how exciton-phonon coupling drives structural changes in the material. Coherent vibrational signals identify key lattice and organic cation modes, providing insights into their role in energy dissipation. These findings deepen our understanding of how 2D perovskites work and pave the way for improving the efficiency and stability of next-generation optoelectronic devices.
Prevalence and transmission risk of colistin and multidrug resistance in long-distance coastal aquaculture
Due to the wide use of antibiotics, intensive aquaculture farms have been recognized as a significant reservoir of antibiotic resistomes. Although the prevalence of colistin resistance genes and multidrug-resistant bacteria (MDRB) has been documented, empirical evidence for the transmission of colistin and multidrug resistance between bacterial communities in aquaculture farms through horizontal gene transfer (HGT) is lacking. Here, we report the prevalence and transmission risk of colistin and multidrug resistance in 27 aquaculture water samples from 9 aquaculture zones from over 5000 km of subtropical coastlines in southern China. The colistin resistance gene mcr−1, mobile genetic element (MGE) intl1 and 13 typical antibiotic resistance genes (ARGs) were prevalent in all the aquaculture water samples. Most types of antibiotic (especially colistin) resistance are transmissible in bacterial communities based on evidence from laboratory conjugation and transformation experiments. Diverse MDRB were detected in most of the aquaculture water samples, and a strain with high-level colistin resistance, named Ralstonia pickettii MCR, was isolated. The risk of horizontal transfer of the colistin resistance of R. pickettii MCR through conjugation and transformation was low, but the colistin resistance could be steadily transmitted to offspring through vertical transfer. The findings have important implications for the future regulation of antibiotic use in aquaculture farms globally to address the growing threat posed by antibiotic resistance to human health.
Horizontal transfer of accessory chromosomes in fungi – a regulated process for exchange of genetic material?
Horizontal transfer of entire chromosomes has been reported in several fungal pathogens, often significantly impacting the fitness of the recipient fungus. All documented instances of horizontal chromosome transfers (HCTs) showed a marked propensity for accessory chromosomes, consistently involving the transfer of an accessory chromosome while other chromosomes were seldom, if ever, co-transferred. The mechanisms underlying HCTs, as well as the factors regulating the specificity of HCTs for accessory chromosomes, remain unclear. In this perspective, we provide an overview of the observed propensity in reported cases of horizontal chromosome transfers. We hypothesize the existence of a signal that distinguishes mobile, i.e., horizontally transferred, accessory chromosomes from the rest of the donor genome. Recent findings in Metarhizium robertsii and Magnaporthe oryzae, suggest that a mobile accessory chromosome may contain putative histones and/or histone modifiers, which could generate such a signal. Based on this, we propose that mobile accessory chromosomes may encode the machinery required for their own horizontal transmission, implying that HCT could be a regulated process. Finally, we present evidence of substantial differences in codon usage bias between core and accessory chromosomes in 14 out of 19 analysed fungal species and strains. Such differences in codon usage bias could indicate past horizontal transfers of these accessory chromosomes. Interestingly, HCT was previously unknown for many of these species, suggesting that the horizontal transfer of accessory chromosomes may be more widespread than previously thought, and therefore an important factor in fungal genome evolution.
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