1.Effects of a school based integrated horticulture curriculum intervention on 24 hour activity behaviors in third grade primary school students
YU Ruida, ZHANG Hao, RONG Siyu, YI Qing, QI Yufei
Chinese Journal of School Health 2026;47(2):199-202
Objective:
To explore the effects of the school based integrated horticulture curriculum intervention on 24 hour activity behaviors among third grade primary school students, so as to provide reference for promoting children s health.
Methods:
In September 2023, a convenience sampling method was used to select 90 third grade primary school students from a primary school in Changsha. Participants were randomly assigned to an intervention group ( n =45) and a control group ( n =45) using a random number table. From February to May 2024, the intervention group received a 12 week integrated curriculum intervention, consisting of two 60 minute sessions per week and covering horticultural practice, home-school collaborative tasks and nutrition knowledge education. The control group continued with routine labor education courses. The triaxial accelerometer and multi sensor sleep monitoring device were used to objectively measure light intensity physical activity (LPA), moderate to vigorous physical activity (MVPA), screen based sedentary behavior (SSB) and sleep (SLP), durations in both groups. Data were analyzed using generalized estimating equations (GEE) and Mann-Whitney U tests.
Results:
The time, group and interaction effects of MVPA time and SLP time before and after intervention in two groups of primary school students were not statistically significant (Wald χ 2=1.54, 2.97, 0.85 ; 0.75, 1.05, 0.48), and the group effect of LPA time (Wald χ 2=1.24) and the time and group effects (Wald χ 2=3.02, 1.18 ) were not statistically significant (all P >0.05). There were statistically significant time and interaction effects for LPA time, as well as interaction effect for SSB time in two groups of primary school students before and after intervention (Wald χ 2=4.78, 3.95, 12.60, all P <0.05). After intervention, LPA time of intervention group [152.23(59.15, 245.80)min] was higher than that of control group [120.70(29.90, 201.20)min], and SSB time of intervention group [55.50(30.00, 125.50)min] was lower than that of control group [220.00(60.00, 285.00)min], with statistically significant differences ( Z =-2.46, -4.48, both P <0.05).
Conclusion
The school horticulture curriculum effectively enhances daily LPA and reduces SSB among third grade primary school students.
2.Effects of SPBC1604.04 Gene Deletion on Mitotic Cell Dynamics in Schizosaccharomyces pombe
Jia-Ni XU ; Jia-Yi HE ; Lang-Lin ZHENG ; Shu-Rong HE ; Shuai MA ; Xiang DING ; Yi-Ling HOU
Progress in Biochemistry and Biophysics 2026;53(5):1471-1484
ObjectiveMitochondria are not only the central organelles responsible for cellular energy metabolism but also play essential roles in regulating cell cycle progression and cytoskeletal dynamics. In recent years, accumulating evidence has demonstrated that mitochondrial homeostasis is closely associated with mitotic progression and cytokinesis. Schizosaccharomyces pombe serves as a classical and well-established model organism. Because its cell cycle regulatory mechanisms are highly conserved throughout evolution, its genetic background is clearly defined, and experimental manipulation is efficient and convenient, it has been extensively applied in studies of cell growth, division, and reproductive mechanisms. The SPBC1604.04 gene encodes a previously uncharacterized mitochondrial carrier protein in Schizosaccharomyces pombe. This gene is located on chromosome II and spans 1 018 base pairs in length. It encodes a protein consisting of 238 amino acids with a predicted molecular mass of approximately 31.03 ku. Bioinformatic analysis predicts that this protein is responsible for the transport of thiamine pyrophosphate (TPP) into mitochondria. However, the effects of SPBC1604.04 gene deletion on mitotic cell dynamics under different temperature conditions have not been fully elucidated. MethodsThe SPBC1604.04 deletion strain of Schizosaccharomyces pombe was used as the experimental model. Fluorescent protein markers were constructed in the deletion background to label mitochondria, microtubules, actin, myosin, the nuclear envelope, and chromosomes. Live-cell imaging was performed using a TCS-SP8 laser scanning confocal microscope under normal temperature conditions (25℃) and heat stress conditions (37℃). Time-lapse microscopy was applied to dynamically monitor mitochondrial morphology and distribution, spindle assembly and elongation, chromosome segregation, as well as the formation and constriction of the actomyosin ring during cytokinesis. ImageJ software was used for quantitative measurements, including microtubule length during mitosis, spindle length at different mitotic stages, mitochondrial fluorescence intensity as an indicator of mitochondrial content, actomyosin ring length, nuclear envelope area, and chromosome segregation timing. Statistical analyses were conducted to compare phenotypic differences between the wild-type and SPBC1604.04 deletion strains at both temperature conditions. Through these analyses, we systematically investigated the impact of SPBC1604.04 deletion on mitotic cell dynamics in fission yeast under both normal physiological conditions and temperature stress. ResultsAt 25℃, compared with wild-type cells, the SPBC1604.04Δ strain exhibited a pronounced tendency toward mitochondrial fragmentation, accompanied by abnormal mitochondrial content and a significant reduction in mitochondrial fluorescence intensity. These observations suggest impaired mitochondrial homeostasis under normal growth conditions. In addition, the constriction time of actomyosin ring during cytokinesis was markedly prolonged, indicating that deletion of SPBC1604.04 affects the dynamics of the contractile machinery. However, no obvious defects were observed in spindle assembly, spindle elongation, or chromosome segregation. Under heat stress at 37℃, mitochondrial morphology in the SPBC1604.04Δ strain showed a tendency to recover toward a continuous tubular network structure. Mitochondrial content was restored, fluorescence intensity increased, and the constriction time of the actomyosin ring returned to levels comparable to those of wild-type cells. These results indicate that the mitotic defects observed at normal temperature are partially or fully alleviated under heat stress conditions. ConclusionThis study demonstrates that deletion of the SPBC1604.04 gene leads to abnormal mitochondrial content in Schizosaccharomyces pombe. The mitochondrial carrier protein SPBC1604.04 participates in regulating actomyosin ring constriction during mitosis but does not appear to be directly involved in the regulation of spindle dynamics or chromosome segregation. Our findings provide key experimental evidence for understanding the functional link between the SPBC1604.04 gene, mitochondrial homeostasis, and mitotic regulation.
3.Effects of SPBC1604.04 Gene Deletion on Mitotic Cell Dynamics in Schizosaccharomyces pombe
Jia-Ni XU ; Jia-Yi HE ; Lang-Lin ZHENG ; Shu-Rong HE ; Shuai MA ; Xiang DING ; Yi-Ling HOU
Progress in Biochemistry and Biophysics 2026;53(5):1471-1484
ObjectiveMitochondria are not only the central organelles responsible for cellular energy metabolism but also play essential roles in regulating cell cycle progression and cytoskeletal dynamics. In recent years, accumulating evidence has demonstrated that mitochondrial homeostasis is closely associated with mitotic progression and cytokinesis. Schizosaccharomyces pombe serves as a classical and well-established model organism. Because its cell cycle regulatory mechanisms are highly conserved throughout evolution, its genetic background is clearly defined, and experimental manipulation is efficient and convenient, it has been extensively applied in studies of cell growth, division, and reproductive mechanisms. The SPBC1604.04 gene encodes a previously uncharacterized mitochondrial carrier protein in Schizosaccharomyces pombe. This gene is located on chromosome II and spans 1 018 base pairs in length. It encodes a protein consisting of 238 amino acids with a predicted molecular mass of approximately 31.03 ku. Bioinformatic analysis predicts that this protein is responsible for the transport of thiamine pyrophosphate (TPP) into mitochondria. However, the effects of SPBC1604.04 gene deletion on mitotic cell dynamics under different temperature conditions have not been fully elucidated. MethodsThe SPBC1604.04 deletion strain of Schizosaccharomyces pombe was used as the experimental model. Fluorescent protein markers were constructed in the deletion background to label mitochondria, microtubules, actin, myosin, the nuclear envelope, and chromosomes. Live-cell imaging was performed using a TCS-SP8 laser scanning confocal microscope under normal temperature conditions (25℃) and heat stress conditions (37℃). Time-lapse microscopy was applied to dynamically monitor mitochondrial morphology and distribution, spindle assembly and elongation, chromosome segregation, as well as the formation and constriction of the actomyosin ring during cytokinesis. ImageJ software was used for quantitative measurements, including microtubule length during mitosis, spindle length at different mitotic stages, mitochondrial fluorescence intensity as an indicator of mitochondrial content, actomyosin ring length, nuclear envelope area, and chromosome segregation timing. Statistical analyses were conducted to compare phenotypic differences between the wild-type and SPBC1604.04 deletion strains at both temperature conditions. Through these analyses, we systematically investigated the impact of SPBC1604.04 deletion on mitotic cell dynamics in fission yeast under both normal physiological conditions and temperature stress. ResultsAt 25℃, compared with wild-type cells, the SPBC1604.04Δ strain exhibited a pronounced tendency toward mitochondrial fragmentation, accompanied by abnormal mitochondrial content and a significant reduction in mitochondrial fluorescence intensity. These observations suggest impaired mitochondrial homeostasis under normal growth conditions. In addition, the constriction time of actomyosin ring during cytokinesis was markedly prolonged, indicating that deletion of SPBC1604.04 affects the dynamics of the contractile machinery. However, no obvious defects were observed in spindle assembly, spindle elongation, or chromosome segregation. Under heat stress at 37℃, mitochondrial morphology in the SPBC1604.04Δ strain showed a tendency to recover toward a continuous tubular network structure. Mitochondrial content was restored, fluorescence intensity increased, and the constriction time of the actomyosin ring returned to levels comparable to those of wild-type cells. These results indicate that the mitotic defects observed at normal temperature are partially or fully alleviated under heat stress conditions. ConclusionThis study demonstrates that deletion of the SPBC1604.04 gene leads to abnormal mitochondrial content in Schizosaccharomyces pombe. The mitochondrial carrier protein SPBC1604.04 participates in regulating actomyosin ring constriction during mitosis but does not appear to be directly involved in the regulation of spindle dynamics or chromosome segregation. Our findings provide key experimental evidence for understanding the functional link between the SPBC1604.04 gene, mitochondrial homeostasis, and mitotic regulation.
4.Mechanism of benzoapyrene-induced mitochondrial DNA damage mediated by PDX-1/TFAM pathway
Rong CUI ; Yi CHENG ; Li WANG ; Xiaohe ZHAI
Journal of Environmental and Occupational Medicine 2026;43(5):575-581
Background Previous studies have found that exposure to benzo[a]pyrene (BaP) can lead to functional impairment of the human pancreas. Pancreatic and duodenal homeobox factor 1 (PDX-1) may play a role in regulating mitochondrial function. It is hypothesized that BaP exposure may interfere with PDX-1 expression in human pancreatic ductal epithelial cells (H6C7), thereby affecting mitochondrial transcription factor A (TFAM). This process could induce mitochondrial DNA (mtDNA) damage, disrupt pancreatic development and function, and elevate the risk of diabetes onset. Objective To investigate the mechanism of BaP-induced mtDNA damage through disruption of the PDX-1/TFAM pathway in a H6C7 cell model. Methods A H6C7 cell injury model was established using different concentrations of BaP. Cell viability was determined using cell counting kit-8 (CCK-8). After 24 h of BaP exposure (5,10, and 20 μmol·L−1), cell morphological and mitochondrial membrane potential (MMP) changes were observed via confocalmicroscopy, and PDX-1/TFAM protein expression levels were assessed. Bioinformatics analysis combined with dual-luciferase reporter assays was used to confirm PDX-1 directly targeting the TFAM promoter. Following PDX-1 overexpression or silencing in BaP treated cells, flow cytometry was used to evaluate viability and apoptosis, while Western blot and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) measured PDX-1/TFAM expression and mitochondrial DNA copy number (mtDNA-cn). Results The cell injury model demonstrated that, compared with the control group, BaP exposure reduced cell viability, disrupted membrane integrity, induced nuclear fragmentation, and decreased MMP. Protein expression levels of PDX-1 and TFAM were significantly downregulated in the 10 and 20 μmol·L−1 groups (P<0.05). Dual-luciferase reporter assays confirmed that PDX-1 overexpression upregulated TFAM levels. Flow cytometry revealed that PDX-1 overexpression significantly reduced apoptosis rate (P<0.001), whereas PDX-1 silencing increased apoptosis rate (P<0.001). Compared with the BaP-only group, BaP+PDX-1 overexpression elevated TFAM protein and mRNA expression as well as mtDNA-cn (P<0.01), while BaP+siRNA-PDX-1 suppressed these parameters (P<0.001). Conclusion BaP exposure promotes apoptosis in human pancreatic cells. PDX-1, a key gene in pancreatic development, regulates the expression of TFAM, a core regulator of mitochondrial function. This interaction triggers changes in MMP and mtDNA-cn, activates the PDX-1/TFAM/mtDNA axis, and ultimately leads to pancreatic cell injury.
5.Mechanism of benzoapyrene-induced mitochondrial DNA damage mediated by PDX-1/TFAM pathway
Rong CUI ; Yi CHENG ; Li WANG ; Xiaohe ZHAI
Journal of Environmental and Occupational Medicine 2026;43(5):575-581
Background Previous studies have found that exposure to benzo[a]pyrene (BaP) can lead to functional impairment of the human pancreas. Pancreatic and duodenal homeobox factor 1 (PDX-1) may play a role in regulating mitochondrial function. It is hypothesized that BaP exposure may interfere with PDX-1 expression in human pancreatic ductal epithelial cells (H6C7), thereby affecting mitochondrial transcription factor A (TFAM). This process could induce mitochondrial DNA (mtDNA) damage, disrupt pancreatic development and function, and elevate the risk of diabetes onset. Objective To investigate the mechanism of BaP-induced mtDNA damage through disruption of the PDX-1/TFAM pathway in a H6C7 cell model. Methods A H6C7 cell injury model was established using different concentrations of BaP. Cell viability was determined using cell counting kit-8 (CCK-8). After 24 h of BaP exposure (5,10, and 20 μmol·L−1), cell morphological and mitochondrial membrane potential (MMP) changes were observed via confocalmicroscopy, and PDX-1/TFAM protein expression levels were assessed. Bioinformatics analysis combined with dual-luciferase reporter assays was used to confirm PDX-1 directly targeting the TFAM promoter. Following PDX-1 overexpression or silencing in BaP treated cells, flow cytometry was used to evaluate viability and apoptosis, while Western blot and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) measured PDX-1/TFAM expression and mitochondrial DNA copy number (mtDNA-cn). Results The cell injury model demonstrated that, compared with the control group, BaP exposure reduced cell viability, disrupted membrane integrity, induced nuclear fragmentation, and decreased MMP. Protein expression levels of PDX-1 and TFAM were significantly downregulated in the 10 and 20 μmol·L−1 groups (P<0.05). Dual-luciferase reporter assays confirmed that PDX-1 overexpression upregulated TFAM levels. Flow cytometry revealed that PDX-1 overexpression significantly reduced apoptosis rate (P<0.001), whereas PDX-1 silencing increased apoptosis rate (P<0.001). Compared with the BaP-only group, BaP+PDX-1 overexpression elevated TFAM protein and mRNA expression as well as mtDNA-cn (P<0.01), while BaP+siRNA-PDX-1 suppressed these parameters (P<0.001). Conclusion BaP exposure promotes apoptosis in human pancreatic cells. PDX-1, a key gene in pancreatic development, regulates the expression of TFAM, a core regulator of mitochondrial function. This interaction triggers changes in MMP and mtDNA-cn, activates the PDX-1/TFAM/mtDNA axis, and ultimately leads to pancreatic cell injury.
6.Clinical practice guidelines for intraoperative cell salvage in patients with malignant tumors
Changtai ZHU ; Ling LI ; Zhiqiang LI ; Xinjian WAN ; Shiyao CHEN ; Jian PAN ; Yi ZHANG ; Xiang REN ; Kun HAN ; Feng ZOU ; Aiqing WEN ; Ruiming RONG ; Rong XIA ; Baohua QIAN ; Xin MA
Chinese Journal of Blood Transfusion 2025;38(2):149-167
Intraoperative cell salvage (IOCS) has been widely applied as an important blood conservation measure in surgical operations. However, there is currently a lack of clinical practice guidelines for the implementation of IOCS in patients with malignant tumors. This report aims to provide clinicians with recommendations on the use of IOCS in patients with malignant tumors based on the review and assessment of the existed evidence. Data were derived from databases such as PubMed, Embase, the Cochrane Library and Wanfang. The guideline development team formulated recommendations based on the quality of evidence, balance of benefits and harms, patient preferences, and health economic assessments. This study constructed seven major clinical questions. The main conclusions of this guideline are as follows: 1) Compared with no perioperative allogeneic blood transfusion (NPABT), perioperative allogeneic blood transfusion (PABT) leads to a more unfavorable prognosis in cancer patients (Recommended); 2) Compared with the transfusion of allogeneic blood or no transfusion, IOCS does not lead to a more unfavorable prognosis in cancer patients (Recommended); 3) The implementation of IOCS in cancer patients is economically feasible (Recommended); 4) Leukocyte depletion filters (LDF) should be used when implementing IOCS in cancer patients (Strongly Recommended); 5) Irradiation treatment of autologous blood to be reinfused can be used when implementing IOCS in cancer patients (Recommended); 6) A careful assessment of the condition of cancer patients (meeting indications and excluding contraindications) should be conducted before implementing IOCS (Strongly Recommended); 7) Informed consent from cancer patients should be obtained when implementing IOCS, with a thorough pre-assessment of the patient's condition and the likelihood of blood loss, adherence to standardized internally audited management procedures, meeting corresponding conditions, and obtaining corresponding qualifications (Recommended). In brief, current evidence indicates that IOCS can be implemented for some malignant tumor patients who need allogeneic blood transfusion after physician full evaluation, and LDF or irradiation should be used during the implementation process.
7.Updates and amendments of the Chinese Pharmacopoeia 2025 Edition (Volume Ⅰ)
LI Hao ; SHEN Mingrui ; ZHANG Pang ; ZHAI Weimin ; NI Long ; HAO Bo ; ZHAO Yuxin ; HE Yi ; MA Shuangcheng ; SHU Rong
Drug Standards of China 2025;26(1):017-022
The Chinese Pharmacopoeia is the legal technical standard which should be followed during the research, production, use, and administration of drugs. At present, the new edition of the Chinese Pharmacopoeia is planned to be promulgated and implemented. This article summarizes and analyzes the main characteristics and the content of updates and amendments of the Chinese Pharmacopoeia 2025 Edition(Volume Ⅰ), to provide a reference for the correct understanding and accurate implementation the new edition of the pharmacopoeia.
8.Design, synthesis and anti-Alzheimer's disease activity evaluation of cinnamyl triazole compounds
Wen-ju LEI ; Zhong-di CAI ; Lin-jie TAN ; Mi-min LIU ; Li ZENG ; Ting SUN ; Hong YI ; Rui LIU ; Zhuo-rong LI
Acta Pharmaceutica Sinica 2025;60(1):150-163
19 cinnamamide/ester-triazole compounds were designed, synthesized and evaluated for their anti-Alzheimer's disease (AD) activity. Among them, compound
9.The Mechanism of Blue Light in Inactivating Microorganisms and Its Applications in The Food and Medical Fields
Ruo-Hong BI ; Rong-Qian WU ; Yi LÜ ; Xiao-Fei LIU
Progress in Biochemistry and Biophysics 2025;52(5):1219-1228
Blue light inactivation technology, particularly at the 405 nm wavelength, has demonstrated distinct and multifaceted mechanisms of action against both Gram-positive and Gram-negative bacteria, offering a promising alternative to conventional antibiotic therapies. For Gram-positive pathogens such as Bacillus cereus, Listeria monocytogenes, and methicillin-resistant Staphylococcus aureus (MRSA), the bactericidal effects are primarily mediated by endogenous porphyrins (e.g., protoporphyrin III, coproporphyrin III, and uroporphyrin III), which exhibit strong absorption peaks between 400-430 nm. Upon irradiation, these porphyrins are photoexcited to generate cytotoxic reactive oxygen species (ROS), including singlet oxygen, hydroxyl radicals, and superoxide anions, which collectively induce oxidative damage to cellular components. Early studies by Endarko et al. revealed that (405±5) nm blue light at 185 J/cm² effectively inactivated L. monocytogenes without exogenous photosensitizers, supporting the hypothesis of intrinsic photosensitizer involvement. Subsequent work by Masson-Meyers et al. demonstrated that 405 nm light at 121 J/cm² suppressed MRSA growth by activating endogenous porphyrins, leading to ROS accumulation. Kim et al. further elucidated that ROS generated under 405 nm irradiation directly interact with unsaturated fatty acids in bacterial membranes, initiating lipid peroxidation. This process disrupts membrane fluidity, compromises structural integrity, and impairs membrane-bound proteins, ultimately causing cell death. In contrast, Gram-negative bacteria such as Salmonella, Escherichia coli, Helicobacter pylori, Pseudomonas aeruginosa, and Acinetobacter baumannii exhibit more complex inactivation pathways. While endogenous porphyrins remain central to ROS generation, studies reveal additional photodynamic contributors, including flavins (e.g., riboflavin) and bacterial pigments. For instance, H. pylori naturally accumulates protoporphyrin and coproporphyrin mixtures, enabling efficient 405 nm light-mediated inactivation without antibiotic resistance concerns. Kim et al. demonstrated that 405 nm light at 288 J/cm² inactivates Salmonella by inducing genomic DNA oxidation (e.g., 8-hydroxy-deoxyguanosine formation) and disrupting membrane functions, particularly efflux pumps and glucose uptake systems. Huang et al. highlighted the enhanced efficacy of pulsed 405 nm light over continuous irradiation for E. coli, attributing this to increased membrane damage and optimized ROS generation through frequency-dependent photodynamic effects. Environmental factors such as temperature, pH, and osmotic stress further modulate susceptibility, sublethal stress conditions (e.g., high salinity or acidic environments) weaken bacterial membranes, rendering cells more vulnerable to subsequent ROS-mediated damage. The 405 nm blue light inactivates drug-resistant Pseudomonas aeruginosa through endogenous porphyrins, pyocyanin, and pyoverdine, with the inactivation efficacy influenced by bacterial growth phase and culture medium composition. Intriguingly, repeated 405 nm exposure (20 cycles) failed to induce resistance in A. baumannii, with transient tolerance linked to transient overexpression of antioxidant enzymes (e.g., superoxide dismutase) or stress-response genes (e.g., oxyR). For Gram-positive bacteria, porphyrin abundance dictates sensitivity, whereas in Gram-negative species, membrane architecture and accessory pigments modulate outcomes. Critically, ROS-mediated damage is nonspecific, targeting DNA, proteins, and lipids simultaneously, thereby minimizing resistance evolution. The 405 nm blue light technology, as a non-chemical sterilization method, shows promise in medical and food industries. It enhances infection control through photodynamic therapy and disinfection, synergizing with red light for anti-inflammatory treatments (e.g., acne). In food processing, it effectively inactivates pathogens (e.g., E. coli, S. aureus) without altering food quality. Despite efficacy against multidrug-resistant A. baumannii, challenges include device standardization, limited penetration in complex materials, and optimization of photosensitizers/light parameters. Interdisciplinary research is needed to address these limitations and scale applications in healthcare, food safety, and environmental decontamination.
10.Effect of The Hydrophilic Amino Acids on Self-assembly Behavior of Short Bola-like Peptides
Xin-Xin GAO ; Yu HAN ; Yi-Lin ZHOU ; Xi-Ya CHEN ; Yu-Rong ZHAO
Progress in Biochemistry and Biophysics 2025;52(5):1290-1301
ObjectiveBola-like short peptides exhibit novel self-assembly properties due to the formation of peptide dimers via hydrogen bonding interactions between their C-terminals. In this configuration, hydrophilic amino acids are distributed at both terminals, making these peptides behave similarly to Bola peptides. The electrostatic repulsive interactions arising from the hydrophilic amino acids at each terminal can be neutralized, thereby greatly promoting the lateral association of β-sheets. Consequently, assemblies with significantly larger widths are typically the dominant nanostructures for Bola-like peptides. To investigate the effect of hydrophilic amino acids on the self-assembly behavior of Bola-like peptides, the peptides Ac-RI3-CONH2 and Ac-HI3-CONH2 were designed and synthesized using the Bola-like peptide Ac-KI3-CONH2 as a template. Their self-assembly behavior was systematically examined. MethodsAtomic force microscopy (AFM) and transmission electron microscopy (TEM) were employed to characterize the morphology and size of the assemblies. The secondary structures of the assemblies were analyzed using circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. Small-angle neutron scattering (SANS) was used to obtain detailed structural information at a short-length scale. Based on these experimental results, the effects of hydrophilic amino acids on the self-assembly behavior of Bola-like short peptides were systematically analyzed, and the underlying formation mechanism was explored. ResultsThe aggregation process primarily involved three steps. First, peptide dimers were formed through hydrogen bonding interactions between their C-terminals. Within these dimers, the hydrophilic amino acids K, R, and H were positioned at both terminals, enabling the peptides to self-assemble in a manner similar to Bola peptides. Next, β-sheets were formed via hydrogen bonding interactions along the peptide backbone. Finally, self-assemblies were generated through the lateral association of β-sheets. The results demonstrated that both Ac-KI3-CONH2 and Ac-RI3-CONH2 could self-assemble into double-layer nanotubes with diameters of approximately 200 nm. These nanotubes were formed by the edge fusion of helical ribbons, which initially emerged from twisted ribbons. Notably, the primary assemblies of these peptides exhibited opposite chirality: nanofibers formed by Ac-KI3-CONH2 displayed left-handed chirality, whereas those formed by Ac-RI3-CONH2 exhibited right-handed chirality. This reversal in torsional direction was primarily attributed to the different abilities of K and R to form hydrogen bonds with water. In contrast, Ac-HI3-CONH2 formed narrower twisted ribbons with a significantly reduced width of approximately 30 nm, which was attributed to the strong steric hindrance caused by the imidazole rings. The multilayer height of these ribbons was mainly due to the unique structure of the imidazole rings, which can function as both hydrogen bond donors and acceptors, thereby promoting aggregate growth in the vertical direction. ConclusionThe final morphology of the self-assemblies resulted from a delicate balance of various non-covalent interactions. By altering the types of hydrophilic amino acid residues in Bola-like short peptides, the relative strength of non-covalent interactions that drive assembly formation can be effectively regulated, allowing precise control over the morphology and chirality of the assemblies. This study provides a simple and effective approach for constructing diverse self-assemblies and lays a theoretical foundation for the development of functional biomaterials.


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