Academia Sinica Logo

Neutrinos only have weak couplings with matter – it requires on average hundreds of light years of water to interact once. Detection and studies of neutrinos are therefore formidable experimental challenges. Nuclear reactors provide an intense source of low energy neutrinos, allowing the studies of neutrino elastic scattering with the atomic nucleus at full quantum-mechanical coherency. The TEXONO experiment led by Dr. Henry Tsz King Wong at the Institute of Physics, Academia Sinica, has proposed in 2005 and since been pursuing this research program with the Kuo-Sheng Reactor Neutrino Laboratory at the Second Nuclear Power Station in Taiwan, pioneering advances in several generations of novel germanium ionization detectors with increasing sensitivities at lower energy. No excesses of neutrino events were observed from data taken prior to the Reactor decommissioning in 2023. New upper limit of 4.7 times the Standard Model predicted cross-sections was placed. The research was published on March 27, 2025 in Physical Review Letters, sets the stage of imminent positive observation with the next-generation detectors, and opens the windows of sensitive searches of new physics.

The newest issue of Academia Economic Papers has been published

The newest issue of Taiwan Economic Forecast and Policy has been published.

Bacteria in polymicrobial environments face threats from phages, competing bacteria, and predatory eukaryotes. While bacterial defenses protect against these threats, their tradeoffs remain underexplored. Here, we investigated the fitness costs of phage resistance in Salmonella enterica, showing that phage-resistant variants suffer competitive disadvantages when co-cultured with rival bacteria. These strains exhibit lipopolysaccharide (LPS) deficiencies, increasing their susceptibility to type VI secretion system (T6SS)-mediated attacks. Mutational analysis and atomic force microscopy revealed that the long O-antigen of LPS acts as a protective shield against T6SS intoxication. Additionally, phages with LPS-targeting endoglycosidases can cleave the O-antigen, independently weakening bacterial competitiveness. Our findings highlight two distinct mechanisms by which phage-driven LPS modifications influence bacterial interactions, revealing tradeoffs that shape microbial competition in polymicrobial communities. This study was published in The EMBO Journal on March 10, 2025. The first authors are Chia-En Tsai, a Ph.D. candidate in the TIGP-MCB program, and Feng-Qi Wang, a master-level research assistant in the Ting lab. This work was conducted in collaboration with Research Fellow, Ing-Shouh Hwang, from the Institute of Physics. The research was funded by the Academia Sinica Career Development Award and the National Science and Technology Council's 2030 Cross-Generation Young Scholars Program – Excellent Young Scholars.

Viruses are widespread infectious agents, but we know little about their origin times due to the general absence of fossil records. The research team of Chuan Ku, Institute of Plant and Microbial Biology, developed a host-calibrated dating method and inferred the evolutionary timescale of giant viruses (Nucleocytoviricota), which cause important diseases (e.g., Mpox, African swine fever) and infect various eukaryotes. The team found that giant viruses are much younger than eukaryotes, originated in an era with significantly higher oxygen levels than before (consistent with their high demand for mitochondria and energy), and spread across all major lineages of eukaryotes through extensive host shifts within the last hundreds of millions of years. This study was published on February 20, 2025 in Molecular Biology and Evolution, and was funded by Academia Sinica Career Development Award and National Science and Technology Council. The first author is Hwee Sze Tee, a postdoctoral research fellow.

A research team led by Dr. Yin-Ru Chiang from the Biodiversity Research Center, Academia Sinica has isolated and characterized a novel anaerobic bacterium from the intestine of the giant mudskipper. This bacterium can convert testosterone (the primary male hormone in humans) into estrogen in an oxygen-free environment. This discovery challenges the traditional scientific understanding that estrogen production requires oxygen and aromatase (a monooxygenase unique to vertebrates). Genomic analysis reveals that this bacterium possesses a special gene cluster that produces a novel methyltransferase, generating estrogen by removing the methyl group between the A/B rings of testosterone. This anaerobic bacterium uses one of the Earth's earliest metabolic pathways (namely Wood-Ljungdahl pathway) to utilize the obtained methyl groups for energy production and cell construction. This new discovery in microbial metabolism suggests that anaerobic bacteria may have possessed the ability to produce estrogen early in Earth's evolutionary history. The research also partially explains why some invertebrates have estrogen in their bodies despite lacking aromatase. Furthermore, the identification of estrogen-producing bacteria in animal guts opens new avenues for potential microbiome-based hypoestrogenism therapies to supplement estrogen in menopausal or ovariectomized females, offering an innovative alternative to current hormone replacement strategies. Future research will prioritize investigating whether anaerobic estrogenesis and corresponding bacteria occur in the intestines of humans and other mammals. The research findings were published in the Proceedings of the National Academy of Sciences (PNAS) on March 08, 2025.

The newest issue of Disquisitions on the Past & Present has been published by the Institute of History and Philology. Articles in this issue (Vol. 43) include

Flourishing Era: Imperial Authority and Local Governance in the Qing China begins with an edict issued in the 50th year of Emperor Kangxi’s reign for a fixed land tax quota, often known for the quote “the increase in population shall never result in additional taxes.

Proper gene expression relies on finely tuned RNA stability, yet its regulatory mechanisms remain unclear. Dr. Chien-Ling Lin’s group at the Institute of Molecular Biology employed massively parallel reporter assays to dissect the regulatory rules of RNA degradation systematically. Statistical modeling by Dr. Yen-Tsung Huang’s team at the Institute of Statistical Sciences revealed that exposure of UA dinucleotides drives RNA degradation. Consistently, fast-turnover genes, such as those regulating innate immunity and appetite, exhibit high UA-dinucleotide ratios in their untranslated regions (UTRs), and mutations that increase UA content reduce RNA half-life. This simple rule may serve as a screening tool for UTR mutation-mediated pathologies and guide the design of synthetic RNAs for therapeutic applications.

A research team led by Dr. Ko-Hsuan Chen from the Biodiversity Research Center, Academia Sinica, discovered an unusual nitrogen-fixing cyanobacterium-fungus symbiosis, now named Phyllosymbia. The symbiosis consists of a filamentous cyanobacteria species (Symbiothallus taiwanensis) that constructs the main three-dimensional leaf-like structure, while the fungal species (Serendipita cyanobacteriicola) resides within the transparent sheath of the cyanobacteria. This structure highlights a unique symbiosis in which the cyanobacteria construct the main body and the fungi are embedded within, offering new insights into the complex interactions between organisms. The study was led by Dr. Ko-Hsuan Chen from the Biodiversity Research Center, Academia Sinica. Participants from the Biodiversity Research Center include Dr. Che-Chih Chen (now affiliated with National Museum of Natural Science), Qiao-Yi Xie, Yi-Ying Chien, Wen-Hong Wang, Dr. Sen-Ling Tang, and Dr. Po-Shun Chuang. The Research Center for Applied Sciences supported the study by providing advanced microscopy imaging techniques through its Optical Microscopy Core Facility. Participants from this center include Dr. Bi-Chang Chen, Chiao-Hui Tu, and Xuejiao Tian. Dr. Romain Darnajoux from the Centre National de la Recherche Scientifique (CNRS), France, also contributed to the study. The research has been published in Science Advances on February 12, 2025, and was selected as the cover story. Illustration：Yi-Ju Li.

The latest issue of《Bulletin of the Institute of Mathematics Academia Sinica New Series》has been published. Articles in this issue include:

Achieving a full understanding of the most catastrophic cosmic events—like supernovae and neutron star mergers—has long been hampered by the elusive quantum behavior of neutrinos, tiny particles whose collective quantum oscillations play a crucial role. Using advanced quantum kinetic transport simulations, researchers found that the key quantum oscillations at microscopic scales average out over larger scales, enabling this effect to be accurately modeled using a simple effective classical transport framework. This innovative approach significantly reduces computational challenges, paving the way for astrophysicists to conduct detailed simulations that could revolutionize our understanding of these phenomena. This research was conducted by physicists from IoP, including Dr. Meng-Ru Wu and Dr. Manu George, along with collaborators Dr. Zewei Xiong (GSI, Germany) and Dr. Chun-Yu Lin (NCHC, Taiwan). The study was published on February 7, 2025, in Physical Review Letters.