Nagahama Institute of Bio-Science and Technology

The performance of inverted perovskite solar cells (PSCs) employing bio-inspired chlorophyll (Chl)-based hole transport materials (HTMs) is frequently limited by interfacial losses and non-radiative recombination. We address this challenge through a molecular-level interface engineering strategy, implementing a novel dopant-free, dual-function polymeric HTM. Synthesized via electrochemical polymerization, the polymeric copper serinyl pyropheophorbide-a features an extended π-conjugated framework for efficient hole extraction. Subsequent surface modification with trifluoroacetate anions at the amino acid terminals generates Lewis base sites that coordinate with undercoordinated Pb2 + ions at the HTM/perovskite interface, enabling simultaneous defect passivation and crystallization control. The optimized devices achieve a champion power conversion efficiency (PCE) of 24.5 %—a record for Chl-based HTMs—with an exceptional fill factor of 85.3 %. Crucially, these PSCs demonstrate outstanding operational stability, retaining 93.2 % of their initial PCE after 2700 h under ambient conditions (unencapsulated). By elucidating the structure-property-performance relationships, this work not only underscores the significant potential of dopant-free Chl-derived materials for next-generation photovoltaics but also provides generalizable insights into multifunctional interfacial modification for highly efficient and stable perovskite devices.

Ornamental medaka strains derived from wild Japanese medaka (Oryzias latipes species complex) are bred worldwide. Over 200 years of selective breeding have produced over 700 strains with a wide variety of phenotypes, including diverse body coloration, scales, eyeball morphology, and fin and body shapes. In this study, we first identified and described 34 phenotypes in ornamental medaka strains. To understand the genomic basis of this phenotypic diversity and the domestication process, we performed whole-genome sequencing on 181 individuals of 86 ornamental Japanese medaka strains. Population genomic analyses revealed that modern ornamental medaka strains are genetically closer to the wild Southern Japan population of the Kansai-Setouchi regions, suggesting the origin of ornamental strains. In addition, the gene loci poc1a, tyr, nme2a, and gabrr2b have undergone selection during domestication. We performed genome-wide association studies analysis for 29 phenotypes observed in ornamental medaka strains and identified strong candidate genes for some phenotypes, including kcnq5a for hirenaga and swallow, bmp5 for deme, adcy5 for orochi, and kitlga for aurora, respectively. We found that loss of exon 8 of adcy5 caused melanism, a dark body color phenotype, in medaka, providing a molecular insight into this phenomenon in vertebrates and human familial dyskinesia. In addition, we uncovered the predominant candidate peaks of genome-wide association studies, including a total of 3,328 genes associated with 26 phenotypes. Our findings highlight the potential of population genomics to explore genotype-phenotype correlations and the genomic basis of body coloration and morphogenesis in medaka.

ABSTRACT We sequenced the nearly complete mitochondrial genome of the hammerhead flatworm Bipalium nobile Kawakatsu and Makino, 1982 using short-read sequencing technology, yielding a 16,018 bp genome comprising 12 protein-coding genes, 22 tRNA genes, and 2 rRNA genes. The composition and order of genes were consistent with those observed in the closely related species Bipalium kewense and Diversibipalium multilineatum , except for the position of tRNA-Glu. Phylogenetic analysis based on all mitochondrial proteins from species within the family Geoplanidae supports the monophyly of a clade comprising B. nobile, B. kewense , and D. multilineatum . The mitochondrial genome sequence obtained in this study provides a valuable resource for investigating the genetic diversity and population structure of B. nobile , a soil-dwelling predator with the potential for global spread as an invasive organism.

Understanding the minimal genetic changes underlying the earliest stages of speciation remains a central challenge in evolutionary biology. However, most model systems used to study early speciation involve pronounced ecological divergence, making it difficult to isolate the initial genetic changes associated with speciation. Here, we examined genetic differences between the cryptic cricket species Loxoblemmus campestris and L. sylvestris, which inhabit the same geographic region without pronounced ecological or morphological divergence. Despite their morphological similarity, the two species exhibited small but consistent molecular phylogenetic divergence in both mitochondrial and nuclear genomes. To investigate the genetic differences between these species, we conducted population genomic and comparative genomic analyses. We identified amino acid substitutions that were fixed within species, including both homozygous and consistently maintained heterozygous variants, across single-copy orthologous genes. Notably, only three genes— Raf, Slit, and Sur-8—had amino acid mutations with low evolutionary probability under neutral expectations and these substitutions are fixed within each species. All three genes are key components of the Ras/MAPK signaling pathway. These findings suggest that early speciation in L. campestris and L. sylvestris may have involved a limited number of mutations with potentially large functional effects, rather than widespread genomic divergence, prior to pronounced phenotypic differentiation. Cryptic Loxoblemmus species provide a useful model for understanding the earliest genomic events of speciation in the absence of pronounced phenotypic divergence.

Data science methodologies can be applied to “molecular archeology.” By statistically inferring ancestral gene or protein sequences from a molecular phylogeny, researchers can recreate ancient molecules for laboratory experiments, allowing direct examination of their properties and structures. This review summarizes studies that applied this approach to investigate how whales and seals readapted to deep-sea diving through the evolutionary modification of myoglobins.