Blockchain technology: development and prospects.

Open AccessCCS ChemistryRESEARCH ARTICLES22 Dec 2022Unexpected Photocatalytic Degeneration of NAD+ for Inducing Apoptosis of Hypoxia Cancer Cells Shengpeng Xia, Haotian Bai, Endong Zhang, Wen Yu, Zhiqiang Gao, Fengting Lv, Yiming Huang, Daoben Zhu and Shu Wang Shengpeng Xia Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049 , Haotian Bai *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] E-mail Address: [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 , Endong Zhang Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 , Wen Yu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049 , Zhiqiang Gao Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049 , Fengting Lv Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 , Yiming Huang *Corresponding authors: E-mail Address: ba[email protected] E-mail Address: [email protected] E-mail Address: [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 , Daoben Zhu Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 and Shu Wang *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] E-mail Address: [email protected] Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 College of Chemistry, University of Chinese Academy of Sciences, Beijing 100049 https://doi.org/10.31635/ccschem.022.202202463 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Developing customized chemical reactions that could regulate a specific biological process on demand is regarded as an advanced and promising strategy for treating diseases. However, conventional chemical reactions become challenging in complex physiological environments, which demand mild reaction conditions, high efficiency, good biocompatibility, and strong controllability. Moreover, the effects of the achieved reactions on the real biological system are usually further lessened. Herein, we describe an advanced photocatalytic reaction that irreversibly converted nicotinamide adenine dinucleotide (NAD+) to nicotinamide and adenosine diphosphate (ADP)-ribose by the cationic conjugated poly(fluorene-co-phenylene) (PFP). This reaction was introduced to tumor cells and triggered cell apoptosis. Under white-light illumination, the photocatalytic reaction decreased the NAD+ ratio in tumor cells, disrupted the mitochondrial membrane potential, inhibited the synthesis of adenosine triphosphate (ATP), and effectively induced apoptosis. We propose a mechanism of the reaction where PFP is photoexcited to PFP*, and the obtained photoelectrons are transferred from PFP* to NAD+ to produce nicotinamide and another unstable intermediate, ADP-ribosyl radical. ADP-ribosyl radical quickly reacts with triethanolamine to form ADP-ribose. This intracellular utilization of a specific photocatalytic reaction could offer a new approach to affect biological function for efficient cancer treatment. Download figure Download PowerPoint Introduction Life is based on continuous cellular metabolism processes, where many substrates and products are often involved in various chemical reactions.1,2 These synergetic reactions, including intracellular redox, enzyme cascade, and reversible reaction, maintain homeostasis of the biological system in individual bodies.3 However, biological metabolic processes with erroneous chemical reactions can cause metabolic disorders and dysfunction, even injury, cancer, and autoimmune disease.4–7 Customized chemical reactions that could regulate specific biological processes are regarded as an advanced and promising strategy for treating diseases.8 However, the complex physiological environments, including the near-neutral pH, mild temperature, pressure, and hypoxic microenvironment, also put many preconditions on developing these reactions.9 The additional demands of excellent controllability and biocompatibility make these investigations more challenging.10 Moreover, cellular self-healing ability11 would further weaken the effects of these reactions because living cells prefer to maintain a chemical balance in the body. Cancer, with high morbidity and mortality, has significantly threatened human life.12–14 Hypoxic microenvironments often cause worse disease outcomes by protecting cancer cells against apoptosis and enhancing the ability of tumor metastasis.3,15,16 Nicotinamide adenine dinucleotide (NAD) is one of the most important coenzymes involved in intracellular redox reactions including cancer metabolism,17 and it generally exists in two forms including oxidized NAD+ and reduced NADH.18 NAD+/NADH levels can affect cancer cell growth by inhibiting the related energy production pathways,6 such as glycolysis, the tricarboxylic acid cycle, and the mitochondrial electron transport chain (ETC). Hence, regulation of NAD+/NADH levels provides an effective strategy for the inhibition of cancer cells by driving the NAD+ and NADH interconversion.8,19,20 However, the regulated ratio of NAD+/NADH can be gradually restored to rebalance the redox levels through the cell repair process.11 Photocatalytic reactions exhibit great potential in achieving desirable intracellular reactions due to the strong controllability, mild reaction conditions,21 and noninvasive remote regulation.22,23 But the poor biocompatibility of noble metal catalysts24,25 could be harmful to living organisms resulting in limited applications in vivo. In comparison, water-soluble conjugated polymers (WSCPs) possess high biocompatibility26–29 and electron transfer efficiency that are beneficial to their applications in photoinduced processes in living organisms.30–32 The ability of WSCPs to catalyze cell-mediated polymerizations33–36 could be exploited in intracellular photocatalytic reactions, which create NAD+/NADH imbalance and regulate cell activities. In this work, we report an emerging photocatalytic reaction and realize the irreversible decomposition of NAD+ to nicotinamide and adenosine diphosphate (ADP)-ribose by the cationic poly(fluorene-co-phenylene) (PFP). The chemical reaction was induced in hypoxic tumor cells to successfully disrupt the cell activity (Scheme 1). The mechanistic investigation shows that the PFP acts as the photocatalyst in the system, and the photoelectrons transfer from the excited PFP (PFP*) to NAD+ to yield nicotinamide and ADP-ribose instead of the naturally occurring bioactive NADH. Therefore, the photocatalytic reaction mediated by PFP irreversibly regulates NAD+ rather than the common strategy based on a reversible reaction between NAD+ and active NADH.3 Inside these tumor cells, the reaction compromises mitochondrial functions that are mainly manifested as blockage of ETC, decreased mitochondrial membrane potential (MMP), and decreased adenosine triphosphate (ATP) level. The disturbed cellular redox cycle and irreversible damage of mitochondria by PFP under irradiation can cause apoptosis and finally disrupt the tumor cell activity. Scheme 1 | Schematic illustration of the photocatalysis reaction by PFP for irreversibly converting NAD+ to nicotinamide and ADP-ribose and inducing apoptosis of hypoxia cancer cells. Download figure Download PowerPoint Experimental Section General methods and materials Cationic PFP was synthesized according to the reported literature procedure.32 All chemical reagents are commercially available and used without further purification. 5,5-Dimethyl-1-pyrroline N-oxide (DMPO) was purchased from Sigma-Aldrich (St. Louis, Missouri, USA). 4T1 cells were purchased from the cell culture center of the Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (Beijing, China). Roswell Park Memorial Institute 1640 medium (RPMI 1640) was purchased from Hyclone (Beijing, China). Fetal bovine serum was purchased from Sijiqing Biological Engineering Materials (Hangzhou, China). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was purchased from Xinjingke Biotechnology Co., Ltd. (Beijing, China). MMP assay kit (JC-1), ATP, and BCA Assay Kits were acquired from Beyotime Biotechnology (Shanghai, China). The NAD+/NADH Ratio Kit was purchased from AAT Bioquest (Pleasanton, California, USA). Deionized water was obtained from a Milli-Q system (Millipore, Bedford, MA, United States). 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindodicarbocyanine (DiD) was provided by Life Technologies (Waltham, Massachusetts, USA). UV–vis absorption spectra were measured by a Thermo Scientific Evolution 201 spectrophotometer (Thermo Fisher, Waltham, Massachusetts, USA), and the fluorescence spectra were taken on a Hitachi F-4500 fluorometer (Hitachi, Tokyo, Japan) equipped with a Xenon lamp excitation source. Ultraviolet photoelectron spectroscopy (UPS) was conducted on an AXIS ULTRA DLD instrument (Kratos, Manchester, UK). Electrochemistry measurements were conducted on an electrochemical workstation (Autolab PGATAT 302N, Metrohm, Herisau, Switzerland). NMR spectra were obtained from a Bruker Avance HD 400 MHz and Bruker AVANCE 600 MHz (Rheinstetten, Germany). The electron paramagnetic resonance (EPR) spectra were measured by Bruker Xenoe nano (Bruker EMXnano, Fällanden, Switzerland). The MTT assay was recorded on a microplate reader (BioTek, Winooski, Vermont, USA). Confocal laser scanning microscopy (CLSM) images were conducted on confocal laser scanning biological microscope (Olympus FV 1200-BX61, Olympus, Hataya, Japan). Intracellular NAD+/NADH ratio assay 4T1 cells were treated in the medium at 37 °C at a density of 5 × 105 cells/well in 6-well plates overnight. Then, the medium with PFP (8 μM) and triethanolamine (TEOA; 4 mM) was used to cultivate 4T1 cells at 37 °C for 12 h. The cells were transferred to a hypoxic environment (1% O2, 5% CO2, 37 °C) for 6 h. After irradiation with 50 mW/cm2 for 20 min, the cells were treated with 250 μL cell lysis buffer. The centrifugal supernatant was collected and used to measure intracellular NAD+/NADH ratio by commercial kit. MMP measurement The 4T1 were added in confocal dishes at a density of 8 × 104 cells/mL and treated in the RPMI medium containing PFP (8 μM) and TEOA (4 mM) at 37 °C for 12 h. Then the cells were incubated in 1% O2 and 5% CO2 at 37 °C for 6 h. After irradiation under white light with 50 mW/cm2 for 30 min, the 4T1 cells were incubated with JC-1 (5×) for 20 min. Then cells were rapidly washed three times by JC-1 (1.25×). The CLSM images were collected at 520–550 nm (λex, 488 nm), and 575–675 nm (λex, 488 nm), respectively. EPR A mixture of 100 μL PFP (1 mM, dimethyl sulfoxide), 20 μL TEOA (1 M), 100 μL DMPO (1 M), 200 μL NAD+ (50 mM), and 580 μL phosphate-buffered saline was irradiated under white light (50 mW/cm2), and the EPR spectra were recorded every 5 min. (Center of Field, 3443.90 G; Sweep Width, 200.0 G; Power, 5 mW; Power Attenuation, 20.00 dB; Modulation Amplitude, 1.0 G; Number of Scans, 6.) Results and Discussion Characteristics of photocatalyst To verify the feasibility of photocatalytic reaction of PFP to catalytically convert NAD+, the photophysical information, energy level, and fluorescence decay kinetics of PFP were collected accordingly. As shown in Figure 1a, PFP exhibited a maximum absorption wavelength of 380 nm, and the peak of fluorescence emission was 429 nm. The band gap of PFP was calculated with a standard method to be 2.97 eV.4 The photoelectric response under a solar simulator demonstrated the possible conversion of absorbed photons into excited electrons ( Supporting Information Figure S1). The highest occupied molecular orbital (HOMO) was determined to be −5.82 eV by UPS (Figure 1b), and the lowest unoccupied molecular orbital (LUMO) was calculated to be −2.85 eV with an optical band gap of 2.97 eV. The Ered and Eox of PFP were +1.32 V and −1.65 V (vs normal hydrogen electrode [NHE]), respectively, obtained by calculations described in the literature.37,38 The reduction potential of NAD+/NADH is −0.54 V versus NHE,39 which is lower than Ered of PFP (+1.32 V vs NHE), and, therefore, suitable to capture the electron from PFP*. The fluorescence decay kinetic curves show that the fluorescence lifetime of PFP decreased from 104 to 23 ns with the addition of NAD+ (Figure 1c). The electron-transfer pathway from PFP to NAD+ under illumination was predicted based on the HOMO/LUMO potential (Figure 1d). The electron captured from the HOMO of PFP could be transferred to NAD+ in the reaction process. All the above characterizations indicate that under illumination PFP generates the holes and electrons, and then the photoelectrons from the PFP HOMO to LUMO transition might reduce NAD+ into the product. The holes are consumed by TEOA whose redox potential (+0.53 V vs NHE) is more negative than PFP (+1.32 V vs NHE). Figure 1 | Material property characterizations of conjugated polymer PFP. (a) Normalized absorption and fluorescence spectrum (in H2O at 25 °C). (b) Ultraviolet photoelectron spectrum of PFP. (c) The fluorescence decay kinetic curves of PFP (10 μM) and PFP (10 μM) + NAD+ (1 mM) with 100 mM TEOA in H2O at 25 °C (λex: 405 nm). (d) The redox potential of the elements involved in the reaction pathway. Download figure Download PowerPoint The photocatalysis reaction to decompose NAD+ According to NMR and mass spectrometry, the photocatalytic reaction of NAD+ generated nicotinamide and ADP-ribose as the products (Figure 2a and Supporting Information Figure S2). Before illumination, 1H NMR peaks corresponding to the nicotinamide unit (a–d), adenine unit (g and h), and the two glycosidic protons (e and f) in NAD+ were identified (black trace), whereas PFP peaks were invisible due to the low concentration. After illumination, the complicated 1H NMR spectral pattern consisted of free nicotinamide (a′–d′, red trace), ADP-ribose (e′–h′), and unreacted NAD+ (not labeled). Major changes of the peaks of nicotinamide and the glycosidic proton e/e′ indicate that the photocatalytic cleavage occurred between nicotinamide and its adjacent ribose. In contrast, minor peak shifts of adenine and its adjacent glycosidic proton f/f′ suggest an intact glycoside on adenine. To further resolve the products, diffusion ordered spectroscopy (DOSY) was performed on the sample after 1 h illumination (Figure 2b). Peaks corresponding to the free nicotinamide exhibited two- to threefold higher diffusion coefficients than other major peaks, and the trend was consistent with the smaller molar mass of nicotinamide (122 g/mol) compared to NAD+ and ADP-ribose. Although the latter two compounds could not be resolved in 1H NMR or DOSY spectra, they were identified on the electrospray ionization-mass spectrometry (ESI-MS) spectrum. The peaks at m/z of 558.1 and 540.1 correspond to ADP-ribose and its dehydrated derivatives, respectively, (Figure 2c), and the peak at 662.1 is unreacted NAD+. To monitor the reaction progress to characterize the kinetics of the photocatalysis, the 1H NMR integrations of H(d) in NAD+ and H(d′) in nicotinamide were calculated (Figure 2d). After 1 h irradiation, 113 μM nicotinamide was obtained, and the products continued to accumulate with extended irradiation time. Figure 2 | The reaction of NAD+ with PFP as the photocatalyst. (a) 1H NMR (D2O) spectra of the reaction mixture before (black) and after illumination (red). (b) DOSY spectrum for further resolving nicotinamide in the illuminated reaction mixture. (c) Negative ion ESI-MS indicates photocatalytic generation of ADP-ribose. (d) Nicotinamide generation under an extended time of illumination. Download figure Download PowerPoint Intracellular catalysis study and therapeutic efficacy The intracellular catalytic effect of PFP photocatalyst on 4T1 cancer cells was investigated. The stability of the cationic conjugated PFP in various physiological solutions was measured ( Supporting Information Figure S3). The similar absorption spectra indicate excellent stability of the conjugated PFP skeleton as a photocatalyst. Meanwhile, the efficiency of this photocatalytic reaction was measured under hypoxic and acidic conditions to simulate the tumor microenvironment. As shown in Supporting Information Figure S4, the efficiency of the photocatalytic reaction was not affected by the low oxygen concentration or acidic pH. It indicates that this photocatalytic reaction mediated by PFP worked in the tumor microenvironment. To exclude the photosensitization effects of PFP, the reactive oxygen species (ROS) production capacity of PFP was measured by 2,7-dichlorodihydrofluorescein (DCFH; Supporting Information Figure S5). In contrast to the efficient photogeneration of ROS under aerobic conditions, negligible ROS were produced by the illumination of PFP under hypoxic conditions. It indicates that the influence of common ROS is not a major contributing factor in this antitumor system. As illustrated in Supporting Information Figure S6, CLSM images of 4T1 cells showed that the blue signal from PFP was surrounded by an entire membrane (labeled with DiD and emitting red signal), which elucidates the successful internalization of PFP. As shown in Supporting Information Figure S7, the PFP, which located in the lysosome, was taken up into cells over the incubation time and retained intracellularly for more than 72 h. This indicates that PFP has the potential to act as a long-term catalyst in cancer cells. To verify that the catalytic reaction could occur in cells, the intracellular NAD+/NADH ratio in hypoxic 4T1 cells treated with PFP under light irradiation was measured. As shown in Figure 3a, the NAD+/NADH ratio of the optical irradiation group treated with PFP decreased from 73% to 65% compared to the dark group. Thus, PFP can catalytically convert NAD+ into nicotinamide and ADP-ribose under white illumination. As an important coenzyme pair in the mitochondrial ETC, and a raw material for photocatalytic reactions, NAD+ can affect the function of mitochondria. The continuous depletion of NAD+ can lead to mitochondrial apoptosis, thereby affecting cell growth. So, the related MMP was measured to further investigate the influence of the explored photocatalytic reaction in hypoxic 4T1 cells. The commercial MMP probe JC-1 was used to visually observe the apoptosis of mitochondria after treatment with PFP and optical illumination. Typically, JC-1 characterizes the state of MMP (ΔΨm) by its monomer or J-aggregate. The J-aggregate initially attaches to the outer membrane of the normal mitochondria and emits red fluorescence. However, the ΔΨm decreases once the NADH-dependent oxidative phosphorylation (OXPHOS) process is inhibited,40 and the JC-1 changes to the monomer and shows green fluorescence, indicating the mitochondria goes into apoptosis (Figure 3b). As displayed in Figure 3c and Supporting Information Figure S8, 4T1 cells exhibited strong green fluorescence after being treated with PFP upon optical illumination in the hypoxic environment, suggesting that the ΔΨm decreased and the mitochondria may be undergoing apoptosis. The variations of the intracellular ATP level were subsequently measured to confirm the mitochondria damage. As shown in Figure 3d, the ATP level of 4T1 cells in the control group had negligible changes no matter with or without white-light illumination. However, the ATP level of the white-irradiation group decreased to 0.11 μg/mg protein (from 0.20 μg/mg protein), which indicates that the process of NAD+ cleavage and product production led to mitochondrial damage, further affecting the normal metabolic process and finally causing cell apoptosis. To visually show the therapeutic effect of the PFP system on 4T1 cancer cells, cell was performed accordingly. As shown in Figure and Supporting Information Figure the cells treated with PFP in the dark strong green of living cells, indicating a high and the promising of PFP, whereas over of the cells treated with PFP under illumination showed the red signal of cells, that PFP had an therapeutic effect on the of tumor cells under white-light illumination. The MTT assay was performed to the cell in the of of PFP. 4T1 cells had high cell even treated with a high concentration of PFP μM) in dark conditions (Figure further its However, upon white-light illumination, the 4T1 cell decreased as the concentration of PFP 2 4T1 cell after being treated with μM PFP, the good therapeutic efficacy of the photocatalytic system due to the catalytic decomposition of NAD+ by this system that in a metabolic process. TEOA and the nicotinamide involved in the system also exhibited negligible ( Supporting Information and As illustrated in Figure and Supporting Information Figure the apoptosis cell ratio of 4T1 cells after being treated with PFP under white-light illumination significantly from to whereas the control or including the white-light group and group. This indicates the good therapeutic efficacy of the photocatalytic system as as the and biocompatibility of optical and PFP respectively. To study the of the described photocatalytic system, two other tumor cell and were by MTT assay ( Supporting Information Figure concentration of PFP 1 the cell of and that the photocatalytic system was effective for various cancer cells, including human cancer cells. to the common strategy of regulation between NAD+ and active the metabolism regulation by PFP is an irreversible reaction, which can the cellular redox cycle and irreversible damage to mitochondria and even cells. The of the photocatalytic reaction to human cells was measured to study the effect of this photocatalytic reaction on normal cells ( Supporting Information Figure The cells high under light and dark conditions. Figure | of the cell apoptosis by PFP photocatalyst upon optical illumination. (a) of the intracellular NAD+ concentration by PFP under optical illumination for 30 min. (b) Schematic illustration of mitochondrial membrane potential changes by (c) Confocal laser scanning microscopy images to show mitochondrial membrane potential (ΔΨm) changes of 4T1 cells after incubation with PFP with or without optical The fluorescence of JC-1 was collected at 575–675 nm (λex, nm), 520–550 nm (λex, 488 nm), respectively. 50 (d) The intracellular ATP levels before and after catalysis by PFP under optical illumination for 30 min. of living and cells by and The fluorescence of and were collected at nm (λex, 488 nm), 575–675 nm (λex, nm), respectively. 200 of 4T1 cells after being treated with PFP μM) with or without white-light illumination (50 for 30 min. Apoptosis and of 4T1 cells after were according to the fluorescence in and Download figure Download PowerPoint The radical and biological characterizations of the photocatalysis reaction EPR assay was conducted to the specific mechanism of the above photocatalytic process. the radical would be by DMPO and to the species the collected radical signal under irradiation was as radical (Figure It that the NAD+ transferred to radical in this photocatalysis process under illumination. the of Figure the electron that NAD+ captured was from PFP*. on the above a mechanism of photocatalytic reaction by PFP is (Figure Under illumination, electrons from PFP* transfer to NAD+, radical and then the holes are captured by After electron ADP-ribose is obtained from the by the of To the of this system in the activity of production was by the catalytic reaction of acid with the conversion of acid to acid with the of and the reaction be inhibited NADH is by photocatalytic The activity of production was by the absorption at nm, which is the absorption of NADH. As shown in Figure the absorption at nm of photocatalytic products exhibited negligible with the addition of the acid and that the photocatalytic product could not be used as a coenzyme of active the absorption decreased significantly after the acid and Thus, photocatalytic products are to in the normal reactions, which that the products obtained in the photocatalytic reaction can not the cycle of the cells. Therefore, the photocatalytic reaction with the function of cancer cells and hypoxic tumor apoptosis. Figure 4 | The radical and biological characterizations of products from NAD+ by PFP under light illumination. (a) EPR spectrum of radical by DMPO under irradiation 50 (b) The mechanism of the photocatalytic reaction by PFP for irreversibly converting NAD+ to nicotinamide and ADP-ribose. (c) The absorption of the PFP + NAD+ group with under dark and compared to the NADH group. upon production under irradiation compared with NADH by Download figure Download PowerPoint In we report a new photocatalytic reaction where irradiated PFP irreversibly NAD+ to nicotinamide and ADP-ribose. The chemical reaction was used to apoptosis in hypoxic tumor cells of The cell demonstrated that the intracellular NAD+ is converted into nicotinamide and ADP-ribose instead of naturally bioactive which is from the pathway. As a reaction of the cellular redox cycle, the continuous depletion of NAD+ disrupted the balance of coenzyme

China has traditionally placed tremendous importance on agricultural research. Meanwhile, in recent years, sustainable agriculture has been increasingly highlighted in both policy agenda and the capital market. However, while terms like environmental friendliness, low carbon, organic and green agriculture have become buzzwords in the media, few meaningful discussions have been raised to examine the relationship between science and technology (S&T) development and sustainable agriculture. What's more, some environmentalists stress that sustainable agriculture should abandon modern agriculture's heavy reliance on science and industrialization, making the link between agricultural S&T and sustainable agriculture seem problematic. What is the truth? If S&T are to play an important role in advancing sustainable agriculture, what is the current status of the field? What factors have caused the sustainable development of agriculture in China? At an online forum organized by the National Science Review (NSR), Hepeng Jia, commissioned by NSR executive editor-in-chief Mu-ming Poo, asked four scientists in the field to examine the dynamic relationship between sustainable agriculture and agricultural S&T in the Chinese context. Jikun Huang Agricultural economist at Peking University, Beijing, China Xiaofeng Luo Agricultural economist at Huazhong Agricultural University, Wuhan, China Jianzhong Yan Agricultural and environmental scientist at Southwest University, Chongqing, China Yulong Yin Veterinary scientist at Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China Hepeng Jia (Chair) Science communication scholar at Cornell University, Ithaca, NY, USA

In recent years, Chinese scientists have achieved significant progress in paleontological discoveries and scientific studies. Series of studies published in top journals, such as Science, Nature and Proceedings of the National Academy of Sciences of the United States of America (PNAS), have astonished the world by presenting beautiful fossils that furnish robust evidence to enrich the understanding of organismic evolution, major extinctions and stratigraphy. It has been portrayed as the heyday in the paleontology of China. What is the status of the field? What factors have caused the avalanche of fossil discoveries in China? What implications can these new discoveries provide for our understanding of current evolution theories? How, given their significant contribution to the world's paleontology scholarship, can Chinese scientists play a due leadership role in the field? At an online forum organized by the National Science Review (NSR), its associate editor-in-chief, Zhonghe Zhou, asked four scientists in the field as well as NSR executive editor-in-chief Mu-ming Poo to join the discussion.Jin MengPaleobiologist at American Museum of Natural HistoryMu-ming PooNeurobiologist at Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShuzhong ShenStratigrapher at Nanjing Institute of Geology and Paleontology, Chinese Academy of SciencesShuhai XiaoPaleobiologist and geobiologist at Virginia Polytechnic Institute and State UniversityZhonghe Zhou (Chair)Paleobiologist at Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences

Jun Deng (left) received his B.Sc. from Lanzhou University and his Ph.D. from the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences (2014) with Professor Ang Li. After a short period of postdoctoral research in the lab of Professor Andrew Myers at Harvard University (2014–2016), he was appointed a Pioneer ‘Hundred Talents Program’ Researcher at Kunming Institute of Botany, Chinese Academy of Sciences in 2017. In December 2020, he moved to Nankai University where he is a professor at the College of Chemistry. He received the Thieme Journals Award (2020). His research focuses on natural product total synthesis and medicinal chemistry. Yefeng Tang (right) earned his B.S. from Lanzhou University (1995–1999) and his M.S. from the Institute of Materia Medica, Chinese Academy of Medical Science (1999–2002). From 2003 to 2006, he pursued his Ph.D. under the guidance of Professor Zhen Yang and Professor Jiahua Chen at Peking University. Subsequently, he conducted postdoctoral research with Prof. K. C. Nicolaou at The Scripps Research Institute between 2006 and 2009. In 2010, he commenced his independent career at the School of Pharmaceutical Sciences, Tsinghua University, where he is now a tenured professor. His primary research interests encompass the total synthesis of natural products, the development of synthetic methodologies, and the discovery of antiviral and anti-aging drugs.

Blockchain technology originated in 2008 when an author codenamed Satoshi Nakamoto published the paper titled “Bitcoin: A Peer-To-Peer Electronic Cash System.” The publication presented an innovative combination of computing-related concepts – peer-to-peer (P2P) networks, cryptography, digital signature, hash functions, and a new consensus algorithm for distributed networks. The Bitcoin network utilizes blockchain technology to process and record transactions securely, and performs online payments without needing a trusted third party. Transactions are validated and recorded in blocks stored in ledger format at network nodes. A “block” refers to the network state stored in sequential blocks containing transactions, hence the term blockchain. One of the limitations of Bitcoin is that its blockchain only allows the sending of monetary transactions. In 2013, Vitalik Buterin, a former member of the Bitcoin community, proposed a platform for developing decentralized applications called Ethereum. This blockchain can run the so-called “Smart Contracts”, or computational codes (programs) that run autonomously and reliably on the blockchain.

The recent move towards more Computer Science in school in the UK has obvious implications for teacher education, both for in-service and pre-service teachers. In England and other parts of the UK we have seen an unprecedented rate of change in the way that curricula are changing from a focus on learning to use software applications to the introduction of Computer Science throughout primary and secondary schools. In this paper we describe some of the challenges that we have faced, the progress made in the integration of CS, and the support provided for teachers in their professional development. Current developments seek to support teachers with varying needs in a holistic way and we propose a transformational model of professional development [1] for CS, both for in-service teachers as well as forming the basis of new teacher training programmes.KeywordsCS teacher educationteacher professional developmentCS secondary school education

China places a great emphasis on boosting its innovative capability, which it says is key to meeting the challenges in economic development and global competition. At the heart of the matter is how the country could produce its own agent of innovation—creative graduates and postgraduates. In a forum chaired by National Science Review's executive associate editor Mu-ming Poo, five panelists from top universities discuss the problems and challenges of higher education in China and in what ways the system needs to be reformed. Yuanfang Chen Physician and Vice Chair of Peking Union Medical College's Expert Committee on Education in Beijing Song Gao Chemist and Vice President of Peking University in Beijing Ke Gong Electronic Engineer and President of Nankai University in Tianjin Yigong Shi Biologist and Dean of Tsinghua University's School of Life Sciences in Beijing Chia-Wei Woo Physicist and Founding President of Hong Kong University of Science and Technology in Hong Kong Mu-ming Poo (Chair) Neuroscientist and Director of Chinese Academy of Sciences’ Institute of Neuroscience in Shanghai

SARS-CoV-2's origin should be investigated worldwide for pandemic prevention

2025 International Conference on Surface Science Technology and Applications (ICSSTA 2025) Conference Announcement Hangzhou, China July 18- July 21, 2025 Conference Theme: Innovation in Surface Science and Technology and International Exchange and Cooperation Surface Science and Technology, as an interdisciplinary and comprehensive technology, mainly focuses on the study of various phenomena and processes occurring on the surface and interface at the atomic or molecular level. It has involved many basic and applied disciplines, including physics, chemistry, mathematics, material science, biology and engineering, and is one of the most active frontier disciplines in the world at present. It has now laid the foundation of technology development in modern industry. In order to bridge the gap between the basic science of surface and interface and the wide applications of surface technology, the 1 st International Conference on Surface Science Technology and Applications was held in 2023 in Chongqing, China. Following the successful ICSSTA 2023, the 2 nd International Conference on Surface Science Technology and Application” (ICSSTA 2025), jointly organized by Southwest Institute of Technology and Engineering, Beihang University, Harbin Institute of Technology, Zhejiang University and other leading Chinese research institutions, will be held in Hangzhou, China from July 18 to 21, 2025. Under the theme “Innovation in Surface Science and Technology and International Exchange and Cooperation”, the conference will feature plenary and keynote presentations by academicians from the Chinese Academy of Sciences, Chinese Academy of Engineering, European Academy of Sciences, and renowned international experts. This gathering will facilitate extensive and in-depth exchanges among scholars, industry leaders, and researchers worldwide, focusing on the latest scientific achievements and industrial developments in surface science technologies. Through interdisciplinary dialogues and strategic partnership building, the conference aims to propel the high-quality advancement of this critical discipline. List of Conference Organizers are available in this PDF.

Welcome to this Special Edition of the Australian Journal of Chemistry, entitled Frontiers in Sino-Australian Polymer Science and Engineering, which showcases recent progress in Australian and Chinese polymer research. The articles contained in this special issue are drawn from key polymer chemistry and engineering laboratories from both countries, whose leaders met in January 2013 for an intensive week of scientific exchange. Polymers are a part of daily life for all of us, be it in health, food packaging, personal electronics, or one of the many industrial applications that polymers are used in; they surround us everywhere, every day. Polymers are therefore a key component of material science and engineering, and polymer research has been a strength of many research institutions in both countries for a long time. Australia and China can look back with pride on more than three decades of successful polymer science and technology cooperation, which includes discoveries and improvements in areas as diverse as water conservation, mining efficiency, medical research, cleaner energy, food security, and disaster management. The two nations have many complementary research strengths in the field of polymers: while Australian researchers are world leaders in advancing polymer synthesis and characterization (e.g. nitroxide-mediated radical polymerization (NMP) and reversible addition– fragmentation chain transfer (RAFT) polymerization methods), Chinese polymer chemists excel at developing industrial applications for polymers (e.g. polymer membranes for clean energy technologies, chemical fibre technologies). Both the Australian and the Chinese governments recognise the importance of research in the area of polymer science and engineering, and polymer science has featured on the list of important research areas in both countries for many years. It is currently listed among the six most important research areas by the Chinese government and is represented in the Australian government’s National Research Priority ‘Frontier Technologies for Building and Transforming Australian Industries’ with its associated priority goal ‘Advanced Materials’. Thanks to funding provided by the Australia-China Science andResearch Fund, an initiative of the AustralianGovernment’s Department of Innovation, Industry, Science, Research and Tertiary Education (DIISRTE), I, with Dr Katharina Ladewig (The University of Melbourne) as activity coordinator, had the pleasure of leading a delegation of outstanding Australian polymer scientists on an official visit to key polymer science and research laboratories in China earlier in 2013. The Australian delegation comprised Drs Cyrille Boyer, Xiaojuan Hao, Professors David Lewis, Dan Li, Martina Stenzel, Dr San Thang, Professors Xungai Wang, Andrew Whittaker, and Dr Xiaoqing Zhang. The 1st Australia China Polymer Mission included attendance of the 1st China–Australia Polymer Meeting (CAPM) hosted by Professor Meifang Zhu at Donghua University (20–21 January 2013; Fig. 1) and subsequent visits of the delegation to the Chinese Academy of Sciences (CAS) in Beijing, Donghua University, Fudan University, Nankai University, Peking University, Shanghai Jiao Tong University, Tianjin University, and Tsinghua University (Fig. 2). The Chinese participants at the 1st CAPM and subsequent hosts at their respective home institutions were Professors Amin Cao, Chao Gao, Junpo He, Zhibo Li, Linqi Shi, Jing Shen, Xinhua Wan, Xu-Ming Xie, Shuguang Yang, Xiaoyan Yuan, Jiong-Xin Zhao, and Jongfeng Zhou. Both the 1st CAPM and the subsequent visits were a great success andwe all look forward to intensified collaborations and scientific discussions in the near future. The key outcomes of the bilateral talks held as part of CAPM were:

PrefaceThe proceedings were written by participants of the International Symposium on Earth Observation for One Belt and One Road (EOBAR) held 16-17 May, 2016 in Beijing, China. Sponsored by the Division of Earth Sciences of the Chinese Academy of Sciences (CAS) and hosted by the Institute of Remote Sensing and Digital Earth, CAS, the conference has aimed to provide an international platform under the theme “quicker, better, broader understanding of One Belt and One Road (OBOR)” for scientists engaged in OBOR researches and earth observation applications.The main topic of the symposium has been well represented by the 58 papers selected in the peer review. The symposium chairman was Huadong GUO (Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences). The Chairs of Scientific Committee was Guanhua XU (Ministry of Science and Technology of the People’s Republic of China), Yong CHEN (China Earthquake Administration) and Valery. G. Bondur (Institute for Scientific Research of Aerospace Monitoring “AEROCOSMOS”, Russian Academy of Sciences). The Organizing Committee was chaired by Bingfang WU (Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences) and Yongwei LIU (Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences).We appreciate the efforts of all the authors who contributed to this conference, and particularly acknowledge the accepted papers for their high quality. We would like to thank the Division of Earth Sciences of CAS, Bureau of International Cooperation of CAS, Group on Earth Observations (GEO), Chinese Academy of Sciences National Natural Science Foundation, without whose generous support, the symposium could not have taken place. Special thanks also go to the staff at IOP Publishing Ltd., UK.Xinwu LI, Jie Liu, Zhongchang SunInstitute of Remote Sensing and Digital EarthChinese Academy of Sciences, China

The current digital and technological changes make bitcoin trading more and more popular. Virtual money (cryptocurrency) is no longer just a fashion, but it is more and more often used in practice on the Internet, and there are no statutory provisions in Polish law, which can lead to many legal complications. Bitcoin first appeared in 2008 thanks to a user disguised as Satoshi Nakamoto who published an article titled Bitcoin: A Peer-to-Peer Electronic Cash System. The concept of bitcoin was published in a nine-page document, and the essence of the concept was the actual creation, launch and placement of a software based on a very complex algorithm for generating bitcoin, based on e.g. on blockchain technology. Satoshi proposed a solution to the problem that had existed since the inception of the Internet, ie how to create a universal electronic payment system. The basic idea of the creator of the bitcoin system was to maintain the anonymity of transactions and property and to exclude unnecessary intermediaries from circulation. From the point of view of computer science, the bitcoin network is a decentralized database of information about the flow of certain numerical values between accounts of system users, where the above numerical values constitute the bitcoin currency. The state and public institutions, in turn, decide on the issue of this currency, its size and creation.The issue of bitcoin forces lawyers to investigate primarily at the level of civil law. The article presents the issues of bitcoin at the level of Polish civil law, and above all de lege lata considerations in the field of both civil and family law regarding the issue of bitcoin division after the divorce of spouses. Discrepancies appearing in the Polish doctrine on the civil law assessment of the nature of bitcoin are presented.

At its core, a blockchain is simply a database for storing digital information where each of time-stamped, published data is together with all preceding and subsequent blocks. What makes blockchain unique from traditional data storage is that data is not stored or controlled within a centralized database, but rather database management is shared by a decentralized network of trustless nodes that each maintain an identical copy of the blockchain. Before data can be published to the blockchain, it must first be validated by a majority of network nodes—typically referred to as or, depending on the consensus methodology used. This concept of “distributed consensus” makes the blockchain inherently tamper resistant and ensures that only verified transactions will be published to the blockchain.1 The two primary consensus methodologies used in blockchain technology today are , first popularized in 2008 by the founder(s) of the Bitcoin2 blockchain, and , which has been used extensively in the development of derivative blockchain projects to help solve the issues of scalabil- 1 Samantha Ravich, “Leveraging Blockchain Technology to Protect the National Security Industrial Base,” July 10, 2017, https://www.fdd.org/analysis/memos/2017/07/10/leveraging-block chain-technology-to-protect-the-national-security-industrial-base/ 2 Satoshi Nakamoto, “Bitcoin: A Peer-to-Peer Electronic Cash System,” 2008, https://bicoin.org/ bitcoin.pdf ity and energy consumption associated with proof-of-workbased blockchains.

In the past years, we have been hearing a lot about cryptocurrency and Blockchain which has brought new scope and technology into the hands of developers and common man. Blockchain technology was first introduced in a whitepaper which went like this: “Bitcoin: A Peer-to-Peer Electronic Cash System,” by Satoshi Nakamoto in 2008. Though Blockchain being a completely new field, many companies are trying to implement Blockchain too. A Blockchain contains of a block which contains a hash of cryptography of the previous block, timestamp and transaction data. The main purpose of this project is to create a Proof-Of-Existence of any type of file or record on the platform of Blockchain. Once submitted, we shall be uploading the file’s unique signature with its associated information into the Private Decentralized Public Ledger. Records stored here can be extracted later to prove that this particular file existed on particular date & time with the associated information uploaded. It is impossible to duplicate the document’s signature or modify the past records both technologically and computationally. Therefore POE can be used to prove any file’s existence in legal matters. It can also be an important part in any organization which will obviously have records of deals, bonds, customer details, employee details etc which if made to generate a POE for each of them, then will be secure and safe because this is something which cannot be hacked.

Cryptocurrency is a relatively young research field. Since its development, when Bitcoin was lanced (2008) (Satoshi, N.: Bitcoin: A Peer-to-Peer Electronic Cash System (2008)), until today it become a highly volatile market with more than 9 thousand types of cryptocurrencies (CoinMarketCap: preţurile criptomonedelor de ast˘azî in funcţie de capitalizare de piaţă (2021)). In latest years several algorithms and techniques have been developed in order to predict the cryptocurrency price evolution. However, a general classification of the available methods has not been proposed yet. For these reasons, in this paper the main ideas underlying cryptocurrency price forecasting are presented and compared. In the first part of the paper is presented the general framework of cryptocurrency development, namely Blockchain Technology and e-Business social environment. In the second part several techniques for cryptocurrency price prediction are presented and their main characteristics are discussed. The last section concludes.KeywordsBitcoinPrice forecastingBlockchainCryptocurrency