Advancing cell-based therapy in sepsis: An anesthesia outlook.

ABSTRACT: Sepsis poses a health challenge globally owing to markedly high rates of morbidity and mortality. Despite employing bundle therapy over two decades, approaches including transient organ supportive therapy and clinical trials focusing on signaling pathways have failed in effectively reversing multiple organ failure in patients with sepsis. Prompt and appropriate perioperative management for surgical patients with concurrent sepsis is urgent. Consequently, innovative therapies focused on remedying organ injuries are necessitated. Cell therapy has emerged as a promising therapeutic avenue for repairing local damage to vital organs and restoring homeostasis during perioperative treatment for sepsis. Given the pivotal role of immune cell responses in the pathogenesis of sepsis, stem cell-based interventions that primarily modulate immune responses by interacting with multiple immune cells have progressed into clinical trials. The strides made in single-cell sequencing and gene-editing technologies have advanced the understanding of disease-specific immune responses in sepsis. Chimeric antigen receptor (CAR)-immune cell therapy offers an intriguing option for the treatment of sepsis. This review provides a concise overview of immune cell therapy, its current status, and the strides made in the context of sepsis research, discussing potential strategies for the management of patients with sepsis during perioperative stages.

In situ measurement of viscoelastic properties of cellular monolayers via graphene strain sensing of elastohydrodynamic phenomena.

Recent advances recognize that the viscoelastic properties of epithelial structures play important roles in biology and disease modeling. However, accessing the viscoelastic properties of multicellular structures in mechanistic or drug-screening applications has challenges in repeatability, accuracy, and practical implementation. Here, we present a microfluidic platform that leverages elastohydrodynamic phenomena, sensed by strain sensors made from graphene decorated with palladium nanoislands, to measure the viscoelasticity of cellular monolayers in situ, without using chemical labels or specialized equipment. We demonstrate platform utility with two systems: cell dissociation following trypsinization, where viscoelastic properties change over minutes, and epithelial-to-mesenchymal transition, where changes occur over days. These cellular events could only be resolved with our platform's higher resolution: viscoelastic relaxation time constants of λ = 14.5 ± 0.4 s-1 for intact epithelial monolayers, compared to λ = 13.4 ± 15.0 s-1 in other platforms, which represents a 30-fold improvement. By rapidly assessing combined contributions from cell stiffness and intercellular interactions, we anticipate that the platform will hasten the translation of new mechanical biomarkers.

Modeling the Maturation of the Vocal Fold Lamina Propria Using a Bioorthogonally Tunable Hydrogel Platform.

Toward the goal of establishing an engineered model of the vocal fold lamina propria (LP), mesenchymal stem cells (MSCs) are encapsulated in hyaluronic acid (HA)-based hydrogels employing tetrazine ligation with strained alkenes. To mimic matrix stiffening during LP maturation, diffusion-controlled interfacial bioorthogonal crosslinking is carried out on the soft cellular construct using HA modified with a ferocious dienophile, trans-cyclooctene (TCO). Cultures are maintained in MSC growth media for 14 days to afford a model of a newborn LP that is homogeneously soft (nLP), a homogeneously stiffened construct zero (sLP0) or 7 days (sLP7) post cell encapsulation, and a mature LP model (mLP) with a stiff top layer and a soft bottom layer. Installation of additional HA crosslinks restricts cell spreading. Compared to the nLP controls, sLP7 conditions upregulate the expression of fibrous matrix proteins (Col I, DCN, and FN EDA), classic fibroblastic markers (TNC, FAP, and FSP1), and matrix remodeling enzymes (MMP2, TIMP1, and HAS3). Day 7 stiffening also upregulates the catabolic activities, enhances ECM turnover, and promotes YAP expression. Overall, in situ delayed matrix stiffening promotes a fibroblast transition from MSCs and enhances YAP-regulated mechanosensing.

The complex dynamics of the 2023 Kahramanmaras, Turkey, Mw 7.8-7.7 earthquake doublet.

The destructive 2023 moment magnitude (Mw) 7.8-7.7 earthquake doublet ruptured multiple segments of the East Anatolian Fault system in Turkey. We integrated multiscale seismic and space-geodetic observations with multifault kinematic inversions and dynamic rupture modeling to unravel the events' complex rupture history and stress-mediated fault interactions. Our analysis reveals three subshear slip episodes during the initial Mw 7.8 earthquake with a delayed rupture initiation to the southwest. The Mw 7.7 event occurred 9 hours later with a larger slip and supershear rupture on its western branch. Mechanically consistent dynamic models accounting for fault interactions can explain the unexpected rupture paths and require a heterogeneous background stress. Our results highlight the importance of combining near- and far-field observations with data-driven and physics-based models for seismic hazard assessment.

Genome-wide identification and transcriptome-based expression profiling of E2 gene family: Implication for potential roles in gonad development of Crassostrea gigas.

In this study, we investigated the role of E2 ubiquitin conjugating enzymes (E2) in the Pacific oyster Crassostrea gigas, with a focus on their involvement in gonad development. We identified 34 E2 genes clustered into nine subgroups and 24 subfamilies. The gene structure and intron-exon location were conserved within the same subfamily, but motif variation suggested functional diversity. Tissue transcriptome analyses revealed that most E2 genes were broadly expressed, with UBE2CL showing specific expression in the female gonad. Expression profiling of E2 genes during early embryo-larvae development stages suggested that five E2 genes were highly expressed in early embryo development, indicating their involvement in cell division processes. Furthermore, by profiling the expression of E2 genes in different gonadal developmental stages, we observed a gradual increase in expression for four genes during gametogenesis, with significantly higher expression in the female gonad at the maturation stage. Similarly, five E2 genes displayed elevated expression levels in the male gonad at the maturation stage, indicating their crucial roles in gonadal development and gametogenesis. Our study provides valuable insights into the potential functions of the E2 gene family in C. gigas, shedding light on the molecular mechanisms underlying gonad development in oysters.

Simultaneous Preparation of Chitin and Flavor Protein Hydrolysates from the By-Products of Shrimp Processing by One-Step Fermentation with Lactobacillus fermuntum.

One-step fermentation, inoculated with Lactobacillus fermentum (L. fermentum) in shrimp by-products, was carried out to obtain chitin and flavor protein hydrolysates at the same time. The fermentation conditions were optimized using response surface methodology, resulting in chitin with a demineralization rate of 89.48%, a deproteinization rate of 85.11%, and a chitin yield of 16.3%. The surface of chitin after fermentation was shown to be not dense, and there were a lot of pores. According to Fourier transform infrared spectroscopy and X-ray diffraction patterns, the fermented chitin belonged to α-chitin. More than 60 volatiles were identified from the fermentation broth after chitin extraction using gas chromatography-ion transfer spectrometry analysis. L. fermentum fermentation decreased the intensities of volatile compounds related to unsaturated fatty acid oxidation or amino acid deamination. By contrast, much more pleasant flavors related to fruity and roasted aroma were all enhanced in the fermentation broth. Our results suggest an efficient one-step fermentation technique to recover chitin and to increase aroma and flavor constituents from shrimp by-products.

Antibacterial Effect of Shrimp By-Products Hydrolysate on Specific Spoilage Organisms of Squid.

In order to further develop and utilize shrimp processing by-products, in this study, a novel antibacterial hydrolysate of shrimp by-products by pepsin hydrolysis (SPH) was prepared. The antibacterial effect of SPH on specific spoilage organisms of squid after end storage at room temperature (SE-SSOs) was investigated. SPH showed an antibacterial effect on the growth of SE-SSOs, with (23.4 ± 0.2) mm of inhibition zone diameter. The cell permeability of SE-SSOs was enhanced after SPH treatment for 12 h. Some bacteria were twisted and shrunk, while pits and pores formed and intracellular contents leaked under scanning electron microscopy observation. The flora diversity of SE-SSOs treated with SPH was determined by a 16S rDNA sequencing technique. Results showed that SE-SSOs were mainly composed of the phyla of Firmicutes and Proteobacteria, among which Paraclostridium (47.29%) and Enterobacter (38.35%) were dominant genera. SPH treatment resulted in a significant reduction in the relative abundance of the genus Paraclostridium and increased the abundance of Enterococcus. Linear discriminant analysis (LDA) of LEfSe conveyed that SPH treatment had a significant impact on altering the bacterial structure of SE-SSOs. The 16S PICRUSt of Cluster of Orthologous Group (COG) annotation revealed that SPH treatment for 12 h could significantly increase the function of transcription level [K], while SPH treatment for 24 h could downregulate post-translational modifications, protein turnover, and chaperone metabolism functions [O]. In conclusion, SPH has a proper antibacterial effect on SE-SSOs and can change the flora structure of SE-SSOs. These findings will provide a technical basis for the development of inhibitors of squid SSOs.

BiRPN-YOLOvX: A weighted bidirectional recursive feature pyramid algorithm for lung nodule detection.

BACKGROUND: Lung cancer has the second highest cancer mortality rate in the world today. Although lung cancer screening using CT images is a common way for early lung cancer detection, accurately detecting lung nodules remains a challenged issue in clinical practice. OBJECTIVE: This study aims to develop a new weighted bidirectional recursive pyramid algorithm to address the problems of small size of lung nodules, large proportion of background region, and complex lung structures in lung nodule detection of CT images. METHODS: First, the weighted bidirectional recursive feature pyramid network (BiPRN) is proposed, which can increase the ability of network model to extract feature information and achieve multi-scale fusion information. Second, a CBAM_CSPDarknet53 structure is developed to incorporate an attention mechanism as a feature extraction module, which can aggregate both spatial information and channel information of the feature map. Third, the weighted BiRPN and CBAM_CSPDarknet53 are applied to the YOLOvX model for lung nodule detection experiments, named BiRPN-YOLOvX, where YOLOvX represents different versions of YOLO. To verify the effectiveness of our weighted BiRPN and CBAM_ CSPDarknet53 algorithm, they are fused with different models of YOLOv3, YOLOv4 and YOLOv5, and extensive experiments are carried out using the publicly available lung nodule datasets LUNA16 and LIDC-IDRI. The training set of LUNA16 contains 949 images, and the validation and testing sets each contain 118 images. There are 1987, 248 and 248 images in LIDC-IDRI's training, validation and testing sets, respectively. RESULTS: The sensitivity of lung nodule detection using BiRPN-YOLOv5 reaches 98.7% on LUNA16 and 96.2% on LIDC-IDRI, respectively. CONCLUSION: This study demonstrates that the proposed new method has potential to help improve the sensitivity of lung nodule detection in future clinical practice.

Rapid character scoring and tabulation of large leaf-image libraries using Adobe Bridge.

Premise: Digital image libraries are an integral part of specimen-based research. However, coding and extracting metadata for hundreds of specimens on a personal computer can be complex. In addition, most existing workflows require downsampling or platform switching and do not link character data directly to the images. Methods and Results: We demonstrate a method to code and embed into images the standard leaf architecture and insect-damage characters that are widely used in paleobotany. Using the visual file browser Adobe Bridge, customizable and searchable keywords can be applied directly and reversibly to individual full-resolution images, and the data can be extracted and formatted into a matrix using scripts. Conclusions: Our approach is intuitive and acts as a digital mimic and complement to the experience of sorting and analyzing specimens in-person. Keywords can be easily customized for other data types that require visual sorting using image libraries.

Exploration on the Influencing Factors of Overseas Students' Online Chinese Learning Intention During the Epidemic Period.

In the information age, online teaching has become an essential field of educational development. The work aims to analyze the factors influencing learning intention of Overseas Students (OSs) during the Coronavirus Disease 2019 (COVID-19). The work adopts the method of Unified Theory of Acceptance and Use of Technology (UTAUT), and implements the influencing factor model of open source software online Chinese learning (OCL). Specifically, the OSs of five colleges and universities in Fuzhou are taken as the research objects. The data is collected through questionnaire survey (QS) and Spss25.0 to analyze the reliability and validity of the data, and Amos23.0 is used to validate the model. The results present that autonomy and self-discipline have become the necessary factors affecting open source software OCL, and personal interests and hobbies are the main factors affecting open source software OCL. Meantime, perceived interest, self-learning management, effort expectation, community influence, performance expectation, and promotion conditions have a significant positive impact on the willingness to promote Chinese learning, and their influence degree increases in turn. The conclusion can provide a novel online teaching and learning strategy for open source software under the COVID-19 situation.

First fossil-leaf floras from Brunei Darussalam show dipterocarp dominance in Borneo by the Pliocene.

The Malay Archipelago is one of the most biodiverse regions on Earth, but it suffers high extinction risks due to severe anthropogenic pressures. Paleobotanical knowledge provides baselines for the conservation of living analogs and improved understanding of vegetation, biogeography, and paleoenvironments through time. The Malesian bioregion is well studied palynologically, but there have been very few investigations of Cenozoic paleobotany (plant macrofossils) in a century or more. We report the first paleobotanical survey of Brunei Darussalam, a sultanate on the north coast of Borneo that still preserves the majority of its extraordinarily diverse, old-growth tropical rainforests. We discovered abundant compression floras dominated by angiosperm leaves at two sites of probable Pliocene age: Berakas Beach, in the Liang Formation, and Kampong Lugu, in an undescribed stratigraphic unit. Both sites also yielded rich palynofloral assemblages from the macrofossil-bearing beds, indicating lowland fern-dominated swamp (Berakas Beach) and mangrove swamp (Kampong Lugu) depositional environments. Fern spores from at least nine families dominate both palynological assemblages, along with abundant fungal and freshwater algal remains, rare marine microplankton, at least four mangrove genera, and a diverse rainforest tree and liana contribution (at least 19 families) with scarce pollen of Dipterocarpaceae, today's dominant regional life form. Compressed leaves and rare reproductive material represent influx to the depocenters from the adjacent coastal rainforests. Although only about 40% of specimens preserve informative details, we can distinguish 23 leaf and two reproductive morphotypes among the two sites. Dipterocarps are by far the most abundant group in both compression assemblages, providing rare, localized evidence for dipterocarp-dominated lowland rainforests in the Malay Archipelago before the Pleistocene. The dipterocarp fossils include winged Shorea fruits, at least two species of plicate Dipterocarpus leaves, and very common Dryobalanops leaves. We attribute additional leaf taxa to Rhamnaceae (Ziziphus), Melastomataceae, and Araceae (Rhaphidophora), all rare or new fossil records for the region. The dipterocarp leaf dominance contrasts sharply with the family's <1% representation in the palynofloras from the same strata. This result directly demonstrates that dipterocarp pollen is prone to strong taphonomic filtering and underscores the importance of macrofossils for quantifying the timing of the dipterocarps' rise to dominance in the region. Our work shows that complex coastal rainforests dominated by dipterocarps, adjacent to swamps and mangroves and otherwise similar to modern ecosystems, have existed in Borneo for at least 4-5 million years. Our findings add historical impetus for the conservation of these gravely imperiled and extremely biodiverse ecosystems.

Improved fatty acid profile reduces body fat and arterial stiffness in obese adolescents upon combinatorial intervention with exercise and dietary restriction.

OBJECTIVE: In order to examine the effect of 4-week combinatorial intervention with exercise training and dietary restriction on serum fatty acids, and to explore the correlation of intervention-induced improvement of serum fatty acid profile with the reduction of body fat and arterial stiffness. METHODS: Thirty-three obese adolescents were randomized into the intervention (n = 19) and control (n = 14) groups. The participants from the intervention group were subjected to 4-week combinatorial intervention with exercise training and dietary restriction while the participants from the control group maintained regular activities and diet habits. Anthropometry, serum fatty acids and arterial stiffness were measured before and after 4-week intervention. RESULTS: The participants upon combinatorial intervention revealed the improved body compositions and serum fatty acid profile, and reduced arterial stiffness when compared with their basal levels and the control participants (p < 0.05). Moreover, the decrease in myristic acid, stearic acid, arachidic acid, behenic acid, palmitoleic acid, and dihomo-γ-linolenic acid, was associated with the reduction in body fat. A positive correlation between arachidonic acid and left brachial ankle pulse velocity was observed, and the increase in docosahexaenoic acid was associated with the reduction of left brachial ankle pulse wave velocity and the enhancement of right ankle brachial index. CONCLUSION: The 4-week combinatorial intervention is a useful strategy to improve serum fatty acid profile along with the reduction of body fat and arterial stiffness in obese adolescents.

Enabling In Vivo Photocatalytic Activation of Rapid Bioorthogonal Chemistry by Repurposing Silicon-Rhodamine Fluorophores as Cytocompatible Far-Red Photocatalysts.

Chromophores that absorb in the tissue-penetrant far-red/near-infrared window have long served as photocatalysts to generate singlet oxygen for photodynamic therapy. However, the cytotoxicity and side reactions associated with singlet oxygen sensitization have posed a problem for using long-wavelength photocatalysis to initiate other types of chemical reactions in biological environments. Herein, silicon-Rhodamine compounds (SiRs) are described as photocatalysts for inducing rapid bioorthogonal chemistry using 660 nm light through the oxidation of a dihydrotetrazine to a tetrazine in the presence of trans-cyclooctene dienophiles. SiRs have been commonly used as fluorophores for bioimaging but have not been applied to catalyze chemical reactions. A series of SiR derivatives were evaluated, and the Janelia Fluor-SiR dyes were found to be especially effective in catalyzing photooxidation (typically 3%). A dihydrotetrazine/tetrazine pair is described that displays high stability in both oxidation states. A protein that was site-selectively modified by trans-cyclooctene was quantitatively conjugated upon exposure to 660 nm light and a dihydrotetrazine. By contrast, a previously described methylene blue catalyst was found to rapidly degrade the protein. SiR-red light photocatalysis was used to cross-link hyaluronic acid derivatives functionalized by dihydrotetrazine and trans-cyclooctenes, enabling 3D culture of human prostate cancer cells. Photoinducible hydrogel formation could also be carried out in live mice through subcutaneous injection of a Cy7-labeled hydrogel precursor solution, followed by brief irradiation to produce a stable hydrogel. This cytocompatible method for using red light photocatalysis to activate bioorthogonal chemistry is anticipated to find broad applications where spatiotemporal control is needed in biological environments.

Glutaredoxin1 knockout promotes high-fat diet-induced obesity in male mice but not in female ones.

This study aims to explore how a high-fat diet and glutaredoxin1 (Glrx1) deficiency affect the development of obesity in male and female mice. A high-fat diet induced great differences in calorie intake and body weight gain between male and female mice; furthermore, the Glrx1 deficiency made male mice more sensitive to a high-fat diet than females. Male mice had higher glucose intolerance, and Glrx1 deficiency aggravated gender differences in glucose intolerance. Glrx1 deficiency aggravated high-fat diet-induced hyperlipidemia. The mRNA levels of HMGCR, Srebf-1c, Srebf-2, CD36, FASN and SCD1 were consistently lower in females than in males. Glrx1 deficiency exacerbated high-fat diet induced liver injury and oxidative stress. Diet but not gender or genotype altered the composition of gut microbiota. These findings provide a new insight into the different susceptibilities to obesity caused by a high-fat diet between males and females.

An image dataset of cleared, x-rayed, and fossil leaves vetted to plant family for human and machine learning.

Leaves are the most abundant and visible plant organ, both in the modern world and the fossil record. Identifying foliage to the correct plant family based on leaf architecture is a fundamental botanical skill that is also critical for isolated fossil leaves, which often, especially in the Cenozoic, represent extinct genera and species from extant families. Resources focused on leaf identification are remarkably scarce; however, the situation has improved due to the recent proliferation of digitized herbarium material, live-plant identification applications, and online collections of cleared and fossil leaf images. Nevertheless, the need remains for a specialized image dataset for comparative leaf architecture. We address this gap by assembling an open-access database of 30,252 images of vouchered leaf specimens vetted to family level, primarily of angiosperms, including 26,176 images of cleared and x-rayed leaves representing 354 families and 4,076 of fossil leaves from 48 families. The images maintain original resolution, have user-friendly filenames, and are vetted using APG and modern paleobotanical standards. The cleared and x-rayed leaves include the Jack A. Wolfe and Leo J. Hickey contributions to the National Cleared Leaf Collection and a collection of high-resolution scanned x-ray negatives, housed in the Division of Paleobotany, Department of Paleobiology, Smithsonian National Museum of Natural History, Washington D.C.; and the Daniel I. Axelrod Cleared Leaf Collection, housed at the University of California Museum of Paleontology, Berkeley. The fossil images include a sampling of Late Cretaceous to Eocene paleobotanical sites from the Western Hemisphere held at numerous institutions, especially from Florissant Fossil Beds National Monument (late Eocene, Colorado), as well as several other localities from the Late Cretaceous to Eocene of the Western USA and the early Paleogene of Colombia and southern Argentina. The dataset facilitates new research and education opportunities in paleobotany, comparative leaf architecture, systematics, and machine learning.

Structural Changes and Evolution of Peptides During Chill Storage of Pork.

In this work, we investigated changes in protein structures in vacuum-packed pork during chill storage and its impact on the in vitro protein digestion. Longissimus dorsi muscles were vacuum packed and stored at 4°C for 3 days. Samples were subjected to Raman spectroscopy, in vitro digestion and nano LC-MS/MS. The 3 d samples had lower α-helix content, but higher ß-sheet, ß-turn, and random coil contents than the 0 d samples (P < 0.05). SDS-PAGE revealed significant protein degradation in the 3 d samples and the differences in digested products across the storage time. Proteome analysis indicated that the 3 d samples had the higher susceptibility to digestion. Increasing protein digestibility was mainly attributed to the degradation of myofibrillar proteins. Thus, exposure of more enzymatic sites in loose protein structure during chill storage could increase protein degradation in meat.

Influence of salting process on the structure and in vitro digestibility of actomyosin.

Salting process is widely used in the process of meat products, whereas few studies have revealed the digestibility of actomyosin after salting treatment, which is closely related with the nutrition of meat. This work reported effect of salting on the structural change and digestibility of actomyosin before and after heat treatment. Actomyosin in 0.4 M and 0.8 M of NaCl had higher content of disulfide bonds, and actomyosin in 0.4 M NaCl showed the largest particle sizes before and after heat treatment. In addition, actomyosin in 0.6 M and 0.8 M of NaCl was oxidized more severely after heat treatment. Based on peptidomics analysis by using liquid chromatography tandem mass spectrometry (LC-MS/MS), actomyosin in 0.6 M was digested more easily, which was followed by sample in 0.8 M and 0.4 M of NaCl in descending order. The lowest digestibility of actomyosin in 0.4 M NaCl was related with its higher content of disulfide bond and severer aggregation behavior. The lower digestibility of actomyosin in 0.8 M NaCl should be related with the higher content of disulfide bonds and surface oxidation. These results highlight the crucial role of salting process in affecting the digestibility of meat protein.

Pork Meat Proteins Alter Gut Microbiota and Lipid Metabolism Genes in the Colon of Adaptive Immune-Deficient Mice.

SCOPE: Excessive consumption of processed meat has been linked to an increasing risk of gut diseases. It is investigated how pork meat proteins affect colon homeostasis between normal and immune-compromised mice. METHODS AND RESULTS: Immune-deficient mice (Rag1-/- ) and wild-type mice are fed a diet that contains 20% casein or protein isolated from cooked pork or dry-cured pork for 3 months. Rag1-/- mice show greater variations in transcriptome responses and higher microbial diversity than wild-type mice after consumption of the pork meat protein diets. Intake of pork meat protein diets also increases body weight and induces colonic oxidative stress, low-grade inflammation, and gene expression involved in immune function, cell cycle, and migration. Key genes like Hmox1, Ppara, and Pparg are highly upregulated by pork meat protein. These changes are associated with decreased abundances of Blautia, Bifidobacterium, and Alistipes and increased abundances of Akkermansia muciniphila and Ruminococcaceae. CONCLUSION: Pork meat proteins affect colon health in both wild-type and Rag1-/- mice by altering the microbiome profile under the complex interaction with adaptive immunity. The findings herein give a new insight into the understanding of meat intake, immunity, and gut health.

Enhanced electrochemical phosphate recovery from livestock wastewater by adjusting pH with plant ash.

In the field of environmental wastewater treatment, it is a very meaningful topic to recover phosphate from swine wastewater in the form of struvite precipitation. The solution pH is one of the important influencing factors in the process of struvite precipitation. In this paper, an attempt was made to recover the phosphate from swine wastewater by adding plant ash. Experimental results have revealed that aeration can be replaced by optimal plant ash adding mode to increase the phosphate recovery efficiency. With the dosages of plant ash and magnesium metal were respectively 11.66 and 3.33 g/L the phosphate recovery efficiency reached 97.69% in 60 min. The efficiency was still above 95% after repeatedly using magnesium pellet for 3 times. The economic evaluation further revealed that the recovery cost of the proposed method was 0.62 $/kg PO4-P.

Influence of hydrothermal treatment on the structural and digestive changes of actomyosin.

BACKGROUND: Heat treatment induces both structural and digestive change of meat protein. However, little has been revealed regarding the associations between structural changes and digested peptides of myofibrillar proteins. This work investigated the effects of heat treatment on the structures and in vitro digestibility of actomyosin, and the peptidomics of the digests were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). RESULTS: Heat treatment resulted in unfolding and aggregation behavior of actomyosin according to the results of surface hydrophobicity and particle size. Formation of disulfide bonds and increase in carbonyl groups that occurred during heat treatment of actomyosin indicated the oxidation of specific residues. Unfolding behavior could elevate digestibility of actomyosin by exposing residues, based on the identification of peptides in digests of actomyosin using LC-MS/MS. However, the disulfide bond proved to reduce the action of digestive proteases, since the peptides number (increased from 56 to 86 in sample heated at 70 °C for 30 min) and peptides intensity in digests largely increased after the addition of dithiothreitol (DTT). Heating at higher temperature (100 °C) induced severer aggregation and oxidation, which resulted in lower digestibility of actomyosin than that heated at 70 °C by burying or damaging partial cleavage sites for digestive proteases. CONCLUSIONS: This work highlights the huge influence of heat treatment on the multi-scale structures of myofibrillar proteins, which largely changed the peptides composition in protein digests. © 2019 Society of Chemical Industry.