Filament Protein Research Articles

Determining the Ideal Temperature and Fermentation Duration to Enhance Crude Protein Content and Reduce Crude Fiber in Rice Bran Using Solid-State Fermentation with Aspergillus niger (USM F4)

Solid-state fermentation (SSF) offers a sustainable method for enhancing the nutritional quality of agricultural residues such as red rice bran. This study aimed to determine the optimal temperature and duration for SSF of red rice bran, focusing specifically on increasing the crude protein (CP) content and reducing the crude fiber (CF) content. SFF of rice bran with Aspergillus niger (A. niger) USM F4 was conducted over 14 consecutive days at three different temperatures (25°C, 35°C, and 45°C). A total of 63 samples of rice bran were divided into three temperature groups, each containing 21 samples. Three samples per group were collected at 48-hour intervals over the 14-day fermentation period. The fermentation process for the collected samples at 48-hour intervals was halted by oven drying at 60°C for 24 hours. The fermented products were subjected to proximate analysis for crude protein (CP), ash, ether extract (EE), and crude fiber (CF) contents using the methods outlined by the Association of Official Analytical Chemists (AOAC). The results revealed a significant effect of temperature and fermentation duration on CP, ash, EE, and CF content when compared to the unfermented rice bran kept at room temperature (25oC). The peak values of CP and the highest degradation of CF across all temperature levels were observed on day 10 while the maximum increase in ash and EE content occurred on day 8. Among the temperature conditions, the highest CP values and the lowest CF values were recorded at 35°C. Conversely, the lowest improvements in CP and CF degradation were observed at 25°C on day 10. In conclusion, the optimal conditions for SSF of rice bran with A. niger to enhance CP content and degrade CF are a temperature of 35°C and a fermentation duration of 10 days.

Effect of Silk Fibroin on the Mechanical and Transport Properties of Agarose Hydrogels.

In this work, the effect of incorporating silk fibroin, a fibrous biocompatible protein, into physically cross-linked agarose hydrogels was investigated as a simple model study to examine how supramolecular fibrous structures influence the properties of the hydrogels. The rheological and transport properties were studied. Fibroin did not change the general viscoelastic properties of the investigated hydrogels but changed the viscoelastic moduli values and also the mesh size, as calculated from rheometry data. Fibroin influenced the mechanical properties depending on its concentration: at lower concentrations, it increased the mesh size, while at higher concentrations, it acted as a filler, decreasing the mesh size. Similarly, the storage and loss moduli were affected, either increasing or decreasing based on the fibroin concentration. The fibroin effect on the diffusion of two dyes differing in their charge was the result of a combination of structural effects, responsible also for changes in the rheological properties, and a result of electrostatic interactions between the charged groups. For positively charged methylene blue, low fibroin concentrations accelerated diffusion, while higher concentrations slowed it by filling network vacancies. In contrast, for negatively charged eosin-B, fibroin strongly impeded diffusion at all concentrations due to electrostatic repulsion, leading to its accumulation at the hydrogel interface. The findings of this work may contribute to an understanding of the behavior of the extracellular matrix or soft tissues as well as to the development of the tailored design of hydrogel materials.

Native Forbs Provide Pollinator Resources and Improve Forage Nutrient Composition, Animal Performance, and Pasture Productivity

Pollinator declines and expectations for more sustainable agriculture, including pasture-based enterprises, bring attention to strategies to enhance the habitat value of grazing lands. We evaluated native warm-season grass (NWSG) pastures with (FORB) and without (CONT) interseeded native forbs in 2021–2023. An analysis was conducted using R with the significance set at p ≤ 0.05. The grass appeared to be weakened predominantly by grazing management practices. Forb density and mass had an inverse relationship in seasons two and three. Total forage mass declined in response to increased grazing days and weakened stands. The forage nutritive compositions differed, with more stable, season-long crude protein and lower fiber concentrations in late-season FORB, which supported higher bodyweight gains and season-long average daily gain. Black-eyed Susan (Rudbeckia hirta; BESU), lanceleaf coreopsis (Coreopsis lanceolata; LCOR), and showy ticktrefoil (Desmodium canadensis; STTF) were the most abundant forbs, and BESU, LCOR, and purple coneflower (Echinacea purpurea; PURC) produced long flowering windows. Cattle grazed STTF, cup plant (Silphium perfoliatum; CUPP), and oxeye sunflower (Helopsis helianthoides) the most. Under continuous stocking, a blend of BESU, LCOR, PURC, STTF, and CUPP produced acceptable cattle gains and provided pollinator resources, suggesting that this model may be a viable means to enhance the sustainability of pastures.

SUMOylation of cardiac myosin binding protein-C reduces its phosphorylation and results in impaired relaxation following treatment with isoprenaline

Systolic and diastolic functions are coordinated in the heart by myofilament proteins that influence force of contraction and calcium sensitivity. Fine control of these processes is afforded by a variety of post-translation modifications that occur on specific proteins at different times during each heartbeat. Cardiac myosin binding protein-C is a sarcomeric accessory protein whose function is to interact transiently with actin, tropomyosin and myosin. Previously many different types of post-translational modification have been shown to influence the action of myosin binding protein-C and we present the first report that the protein can be modified covalently by the small ubiquitin like modifier protein tag. Analysis by mass spectrometry suggests that there are multiple modification sites on myosin binding protein-C for this tag and single point mutations did not serve to abolish the covalent addition of the small ubiquitin like modifier protein. Functionally, our data from both model human embryonic kidney cells and transfected neonatal cardiac myocytes suggests that the modification reduces phosphorylation of the filament protein on serine 282. In cardiac myocytes, the hypo-phosphorylation coincided with a significantly slower relaxation response following isoprenaline induced contraction. We hypothesise that this novel modification of myosin binding protein-C represents a new level of control that acts to alter the relaxation kinetics of cardiac myocytes.

Structural basis for adhesin secretion by the outer-membrane usher in type 1 pili

Gram-negative bacteria produce chaperone-usher pathway pili, which are extracellular protein fibers tipped with an adhesive protein that binds to a receptor with stereochemical specificity to determine host and tissue tropism. The outer-membrane usher protein, together with a periplasmic chaperone, assembles thousands of pilin subunits into a highly ordered pilus fiber. The tip adhesin in complex with its cognate chaperone activates the usher to allow extrusion across the outer membrane. The structural requirements to translocate the adhesin through the usher pore from the periplasm to the extracellular space remains incompletely understood. Here, we present a cryoelectron microscopy structure of a quaternary tip complex in the type 1 pilus system from Escherichia coli, which consists of the usher FimD, chaperone FimC, adhesin FimH, and the tip adapter FimF. In this structure, the usher FimD is caught in the act of secreting its cognate adhesin FimH. Comparison with previous structures depicting the adhesin either first entering or having completely exited the usher pore reveals remarkable structural plasticity of the two-domain adhesin during translocation. Moreover, a piliation assay demonstrated that the structural plasticity, enabled by a flexible linker between the two domains, is a prerequisite for adhesin translocation through the usher pore and thus pilus biogenesis. Overall, this study provides molecular details of adhesin translocation across the outer membrane and elucidates a unique conformational state adopted by the adhesin during stepwise secretion through the usher pore. This study elucidates fundamental aspects of FimH and usher dynamics critical in urinary tract infections and is leading to antibiotic-sparing therapeutics.

Optimal fertilization of Marandu grass with gelatin industry sludge

This study determined optimal fertilization levels for Marandu grass (Urochloa brizantha cv. Marandu) as a forage using sludge from the gelatin industry. The experiment was performed in a greenhouse with five treatments: three rates of gelatin sludge application (0, 200, and 300 m3 ha-1), an organo-mineral (100 m3 ha-1 + mineral: 60 mg dm-3 N), and pure mineral fertilizer (100 mg dm-3 N) with six replicates. Plant and stem height, number of tillers, leaves, leaves/tiller, chlorophyll index, dry mass (leaves, roots, and residue), crude protein, neutral and acid detergent fiber, macronutrient, and micronutrient concentrations were measured. Plant and stem height, number of tillers, leaves, and biomass production increased linearly as gelatin sludge dosage increased. There was a linear increase in crude protein with reduction in neutral detergent fiber and acid detergent fiber with increasing gelatin sludge fertilization. Gelatin sludge dosage did not affect the contents of P, Mg, S, Cu, and Fe. Only Mn had a positive linear response to gelatin sludge with reduction at the highest rate. The 300 m3 ha-1 dosage of gelatin sludge increased biomass production and chlorophyll index. In contrast, the organo-mineral fertilizer promoted higher crude protein and lower neutral detergent fiber concentrations in grass. The gelatin sludge dosage of 300 m3 ha-1 improved the nutritive value of Marandu grass compared to mineral fertilizer. Gelatin sludge is a promising pasture amendment for growing Marandu grass as it recycles industrial animal waste for a more integrated livestock-cropping system.

Ackermannviridae bacteriophage against carbapenem-resistant Klebsiella pneumoniae of capsular type 64.

Lytic bacteriophages (phages) are promising clinically viable therapeutic options against carbapenem-resistant Klebsiella pneumoniae (CRKP). In China, the predominant strains are those assigned to sequence type 11 and capsular type 64 (ST11-KL64). The emergence of phage resistance is a major bottleneck hindering effective phage therapy, requiring more new phages to provide the flexibility for creating different phage cocktails. However, the majority of phages against ST11-KL64 CRKP belong to the genus Przondovirus of the family Autographiviridae, which limits the options for constructing cocktails. We recovered a novel lytic phage of the genus Taipeivirus within the family Ackermannviridae against ST11-KL64 CRKP from a river in China. We phenotypically characterized this phage and obtained its genome sequence for analysis. This phage can inhibit the growth of ST11-KL64 CRKP for 6.5 h at a 0.1 multiplicity of infection and exhibits a narrow host range, being unable to attack CRKP strains of the other 30 capsular types. This phage carries no genes encoding antimicrobial resistance, virulence, or lysogeny. It is stable across a wide range of temperatures and pH values, making it suitable for phage therapy. Unlike other Taipeivirus phages, P01 has two tail spike proteins and a unique tail fiber protein. The distinct tail composition of this phage contributes to its activity against ST11-KL64 CRKP and its narrow host range. Taken together, we recovered a phage of a novel viral species with the potential for therapy, which expands the phage biobank against CRKP.

Nucleation limited assembly and polarized growth of a de novo-designed allosterically modulatable protein filament.

The design of inducibly assembling protein nanomaterials is an outstanding challenge. Here, we describe the computational design of a protein filament formed from a monomeric subunit which binds a peptide ligand. The cryoEM structure of the micron scale fibers is very close to the computational design model. The ligand acts as a tunable allosteric modulator: while not part of the fiber subunit-subunit interfaces, the assembly of the filament is dependent on ligand addition, with longer peptides having more extensive interaction surfaces with the monomer promoting more rapid growth. Seeded growth and capping experiments reveal that the filaments grow primarily from one end. Oligomers containing 12 copies of the peptide ligand nucleate fiber assembly from monomeric subunit and peptide mixtures at concentrations where assembly occurs very slowly, likely by generating critical local concentrations of monomer in the assembly competent conformation. Following filament assembly, the peptide ligand can be exchanged with free peptide in solution, and it can be readily fused to any functional protein of interest, opening the door to a wide variety of tunable engineered materials.

Pengaruh Substitusi Tepung Ikan dengan Tepung Larva BSF dalam Ransum terhadap Konsumsi Protein Kasar, Lemak Kasar dan Serat Kasar pada Burung Puyuh

The research was carried out experimentally at the Non-Ruminant Livestock Laboratory, Faculty of Animal Husbandry, Hasanuddin University from April to June 2019. This research aims to determine the effect of substituting fish meal with BSF larvae meal in the ration on the consumption of crude protein, crude fat and crude fiber in quail. 60 female quail were used in this study using cages measuring 90 x 60 x 30 cm. This research method used a completely randomized design (CRD) consisting of four treatments and five replications, divided randomly based on treatment as follows: P0 Ration without adding BSF larval meal, P1 = BSF larval meal 3.183% (6.67% crude fish meal protein) , P2=BSF larval meal 6.370% (3.34% fish meal crude protein), P3=BSF larval meal 9.565% (0% fish meal crude protein). The variables observed were the consumption of crude protein, crude fat and crude fiber in quail. The data obtained were then analyzed using IBM SPSS Statistics 25 software. The results of the analysis of the effect of substituting fish meal with BSF larvae meal in the ration had no significant effect (P>0.05) on the consumption of crude protein, crude fat and crude fiber in quail.

Potential Utilization of Defective Fruit Juice Products for Black Soldier Fly Cultivation to Reduce Waste Generation in the Beverage Industry

The waste of fruit juice and tea defective products has organic content that conventionally has the potential to be utilized as a medium or place for maggot growth, but until now it has not been equipped with supporting scientific studies. Therefore, the objectives of the study are: 1) Assessing the characteristics of fruit juice and tea product waste, 2) Assessing the effectiveness of maggot in reducing fruit juice and tea product waste. This research is experimental in nature using variations in the composition of fruit juice and tea product waste as a source of nutrition for maggot which is carried out for 12 days. This variation uses the Complete Randomized Design method with 3 (three) treatments, namely variations in the composition of 60% tea + 40% fruit juice waste (S1), 50% tea + 50% fruit juice waste (S2), and 40% tea + 60% fruit juice waste (S3) in duplo. In addition, this study was completed with a control treatment. The results showed that the characteristics of fruit juice and tea waste containing protein (3.78-4.59%), fat (0.90-1.31%), carbohydrates (28.15-29.15%), crude fiber (2.42-3.12%) can be used as maggot cultivation media. The highest protein and crude fiber contents were found in the S3 composition waste at 4.59% and 3.12%. Maggot cultivation results that showed the highest fat and carbohydrate content were found in S1 composition waste at 1.31% and 29.15%. The recommended composition variation is S1 composition with the highest substrate consumption value and waste reduction index of 57.47% and 20.06%.

Functionalization of silk with actinomycins from Streptomyces anulatus BV365 for biomedical applications.

Silk, traditionally acclaimed as the "queen of fiber," has been widely used thanks to its brilliant performance such as gentleness, smoothness and comfortableness. Owing to its mechanical characteristics and biocompatibility silk has a definitive role in biomedical applications, both as fibroin and fabric. In this work, the simultaneous dyeing and functionalization of silk fabric with pigments from Streptomyces anulatus BV365 were investigated. This strain produced high amounts of orange extracellular pigments on mannitol-soy flour agar, identified as actinomycin D, C2 and C3. The application of purified actinomycins in the dyeing of multifiber fabric was assessed. Actinomycins exhibited a high affinity towards protein fibers (silk and wool), but washing durability was maintained only with silk. Acidic condition (pH5) and high temperature (65°C) facilitated the silk dyeing. The morphologies and chemical components of the treated silk fabrics were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy. The results showed the pigments bind to the silk through interaction with the carbonyl group in silk fibroin rendering the functionalized, yet surface that does not cause skin irritation. The treated silk exhibited a remarkable antibacterial effect, while the biocompatibility test performed with 3D-reconstructed human epidermis model indicated safe biological properties, paving the way for future application of this material in medicine.

Hemp Seed (Cannabis sativa L.) Varieties: Lipids Profile and Antioxidant Capacity for Monogastric Nutrition.

The present research aimed to study the proximate composition, fatty acid profile, antiox-idant activity, total phenolic and N-trans-Caffeoyltyramine content of three distinct varieties of hemp seeds (Carmaenecta, Enectaliana and Enectarol, grown in a Mediterranean area (Central Italy), as feed in the diet of farm animals. Proximate composition was determined using the official methods of analyses; the fatty acid profile was determined by gas chromatography, total phenolic content (TPC) and the scavenging activity (DPPH• and ABTS•+) by the colorimetric method, and N-trans-Caffeoyltyramine content by HPLC analysis. The hemp seed Enectarol showed the highest total lipid content and the best antioxidant activity with the highest TPC, N-trans-Caffeoyltyramine content, and ABTS•+, and the lowest peroxidation index and DPPH•; Carmaenecta showed the best fatty acid profile and nutritional indices (atherogenic and thrombogenic indices and hypocholesterolemic/hypercholesterolemic ratio), and Enectaliana showed the highest crude protein and dietary fiber content. The differences observed in the chemical composition, fatty acid profile and antioxidant activity are because of the varieties, considering that all other growing conditions were the same. The results obtained suggest that hemp seed can be used as a source of lipid and protein in animal diets due to their valuable antioxidant activity and as a rich source of essential fatty acids.

Intestinal gluconeogenesis controls the neonatal development of hypothalamic feeding circuits

ObjectiveIntestinal gluconeogenesis (IGN) regulates adult energy homeostasis in part by controlling the same hypothalamic targets as leptin. In neonates, leptin exhibits a neonatal surge controlling axonal outgrowth between the different hypothalamic nuclei involved in feeding circuits and autonomic innervation of peripheral tissues involved in energy and glucose homeostasis. Interestingly, IGN is induced during this specific time-window. We hypothesized that the neonatal pic of IGN also regulates the development of hypothalamic feeding circuits and sympathetic innervation of adipose tissues. MethodsWe genetically induced neonatal IGN by overexpressing G6pc1 the catalytic subunit of glucose-6-phosphatase (the mandatory enzyme of IGN) at birth or at twelve days after birth. The neonatal development of hypothalamic feeding circuits was studied by measuring Agouti-related protein (AgRP) and Pro-opiomelanocortin (POMC) fiber density in hypothalamic nuclei of 20-day-old pups. The effect of the neonatal induction of intestinal G6pc1 on sympathetic innervation of the adipose tissues was studied via tyrosine hydroxylase (TH) quantification. The metabolic consequences of the neonatal induction of intestinal G6pc1 were studied in adult mice challenged with a high-fat/high-sucrose (HFHS) diet for 2 months. ResultsInduction of intestinal G6pc1 at birth caused a neonatal reorganization of AgRP and POMC fiber density in the paraventricular nucleus of the hypothalamus, increased brown adipose tissue tyrosine hydroxylase levels, and protected against high-fat feeding-induced metabolic disorders. In contrast, inducing intestinal G6pc1 12 days after birth did not impact AgRP/POMC fiber densities, adipose tissue innervation or adult metabolism. ConclusionThese findings reveal that IGN at birth but not later during postnatal life controls the development of hypothalamic feeding circuits and sympathetic innervation of adipose tissues, promoting a better management of metabolism in adulthood.

Differential immunological responses in lamb rumen and colon to alfalfa hay and wheat straw in a concentrate-rich diet: insights into microbe-host interactions.

The impact of a concentrate-rich (CR) diet on the gut microbiome and epithelium homeostasis is well documented. However, it has not been systematically studied whether and how host-microbial interaction contributes to the immune homeostasis in the rumen and colon of lambs fed alfalfa hay and wheat straw, alone or combined, in a CR diet. In all, 63 lambs (initial body weight, 16.69 ± 1.50 kg) were randomly allotted to three dietary groups, each consisting of three pens with seven lambs per pen. Over 14 weeks, the lambs were fed diets as follows: 60% concentrate supplemented with either 40% wheat straw (WG), 20% alfalfa hay combined with 20% wheat straw (MG), or 40% alfalfa hay (AG). The present findings showed that lambs in the AG group had greater (P < 0.05) IgG and lower (P = 0.067) tumor necrosis factor-alpha concentrations relative to those in the MG and WG groups. The 16S rRNA analysis highlighted that various bacterial phyla and genera in the rumen and colon preferentially degrade fiber and starch derived from alfalfa hay and wheat straw. The weighted gene co-expression network analysis revealed that the bacterial genera from the Firmicutes are broadly associated with genes involved in various signaling pathways, underscoring the potential role of Firmicutes as key drivers of host-microbial interactions under the present feeding conditions. These findings shed light on the fact that the rumen and colon immune homeostasis is distinctively influenced by diets of alfalfa hay, wheat straw, or their combination in a CR diet. Further studies should examine the prolonged effects of replacing wheat straw with alfalfa hay in a concentrate-rich diet formulated to provide equivalent neutral detergent fiber levels. This could reveal how various forage fibers influence host-microbial interactions and gut health.IMPORTANCEIn contemporary feedlots, a growing trend is to feed animals a concentrate-rich (CR) diet that could disrupt the synchronized interplay between microbes and host metabolism, leading to altered metabolic functions. Wheat straw and alfalfa hay have different levels of protein and neutral detergent fiber, each with varying rates of digestion. It is unclear how including alfalfa hay and wheat straw, alone or combined in a CR diet, influences the host-microbial consortia and immune homeostasis. Herein, we showed that rumen and colon showed differential immune responses to the alfalfa hay, wheat straw, or both. Bacterial genera preferentially degrade fiber and starch derived from alfalfa hay, wheat straw, or both. Bacterial genera from Firmicutes phylum play a pivotal role in driving the host-microbial interactions, as indicated by their extensive association with genes across various signaling pathways.

Anisotropic swelling due to hydration constrains anisotropic elasticity in biomaterial fibers

Naturally occurring protein fibers often undergo anisotropic swelling when hydrated. Within a tendon, a hydrated collagen fibril’s radius expands by 40% but its length only increases by 5%. The same effect, with a similar relative magnitude, is observed for single hair shafts. Fiber hydration is known to affect elastic properties. Here we show that anisotropic swelling constrains the anisotropic linear elastic properties of fibers. First we show, using data from disparate previously reported studies, that anisotropic swelling can be described as an approximately linear function of water content. Then, under the observation that the elastic energy of swelling can be minimized by the anisotropic shape, we relate swelling anisotropy to elastic anisotropy — assuming radial (transverse) symmetry within a cylindrical geometry. We find an upper bound for the commonly measured axial Poisson ratio νzx<1/2. This is significantly below recently estimated values for collagen fibrils extracted from tissue-level measurements, but is consistent with both single hair shaft and single collagen fibril mechanical and hydration studies. Using νzx, we can then constrain the product γ≡(1−νxy)Ez/Ex — where νxy is the seldom measured transverse Poisson ratio and Ez/Ex is the ratio of axial to radial Young’s moduli.

Nanofilament organization in highly tough fibers based on lamin proteins

The escalating plastic pollution crisis necessitates sustainable alternatives, and one promising solution involves replacing petroleum-based polymers with fibrous proteins. This study focused on the recombinant production of intracellular fibrous proteins, specifically Caenorhabditis elegans lamin (Ce-lamin). Ce-lamins spontaneously organize within the cell nucleus, forming a network of nanofilaments. This intricate structure serves as an active layer that responds dynamically to mechanical strain and stress. Herein, we investigated the arrangement of nanofilaments into nanofibrils within wet-spun Ce-lamin fibers using alcoholic solutions as coagulants. Our goal was to understand their structural and mechanical properties, particularly in comparison with those produced with solutions containing Ca+2 ions, which typically result in the formation of nanofibrils with a collagen-like pattern. The introduction of ethanol solutions significantly altered this pattern, likely through rearrangement of the nanofilaments. Nevertheless, the resulting fibers exhibited superior toughness and strain, outperforming various synthetic fibers. The significance of the nanofilament structure in enhancing fiber toughness was emphasized through both the secondary structure transition during stretching and the influence of the Q159K point mutation. This study improves our understanding of the structural and mechanical aspects of Ce-lamin fibers, paving the way for the development of eco-friendly and high-quality fibers suitable for various applications, including medical implants and composite materials.

Molecular architecture of the assembly of Bacillus spore coat protein GerQ revealed by cryo-EM

Protein filaments are ubiquitous in nature and have diverse biological functions. Cryo-electron microscopy (cryo-EM) enables the determination of atomic structures, even from native samples, and is capable of identifying previously unknown filament species through high-resolution cryo-EM maps. In this study, we determine the structure of an unreported filament species from a cryo-EM dataset collected from Bacillus amyloiquefaciens biofilms. These filaments are composed of GerQ, a spore coat protein known to be involved in Bacillus spore germination. GerQ assembles into a structurally stable architecture consisting of rings containing nine subunits, which stacks to form filaments. Molecular dockings and model predictions suggest that this nine-subunit structure is suitable for binding CwlJ, a protein recruited by GerQ and essential for Ca2+-DPA induced spore germination. While the assembly state of GerQ within the spores and the direct interaction between GerQ and CwlJ have yet to be validated through further experiments, our findings provide valuable insights into the self-assembly of GerQ and enhance our understanding of its role in spore germination.

Underlying mechanisms of different polysaccharides on the texture characteristics and protein digestibility of soybean curd

This study aimed to investigate the effects of the addition of potato starch (PS) and guar gum (GG) at different concentrations (0.4 and 0.8%) on the physical properties, protein conformation, and in vitro digestibility of soybean curd. The results indicated that the PS acted as a filler in the protein structure, enhancing the firmness, springiness, and chewiness of the soybean curd. GG encapsulated the disorganized filamentous protein matrix, increasing the adhesiveness of the soybean curd. The addition of GG and PS reduced the hydrophobic interactions and disulfide bonds responsible for cross-linking soybean curd proteins, while forming more hydrogen bonds with the proteins (p < 0.05). GG formed the most hydrogen bonds with the proteins, as well as reduced β-sheet content and transformed into more random coil and β-turn (p < 0.05). Also, the addition of GG (particularly at 0.8%) significantly reduced the degree of protein hydrolysis (31.98%) in soybean curd, resulting in fewer small molecular weight peptides and lower total amino acid content (3386.79 μg/g protein) at the end of in vitro digestion (p < 0.05). In contrast, the addition of a small amount of PS (0.4%) did not affect the protein digestibility of soybean curd. This study clarified the impact of polysaccharide additions on modifying the soybean curd texture and protein digestibility.

Abstract B079: Disassembly of embryonic keratin filaments promotes pancreatic cancer metastases

Abstract Keratin 17 (K17), an intermediate filament protein typically expressed during embryonic development, is a hallmark of one of the most aggressive pancreatic ductal adenocarcinoma (PDAC) subtypes. Its expression is also associated with poor patient survival and resistance to first-line therapies. However, the mechanistic roles of K17 in malignancy remain largely unexplored. Here, we demonstrate that K17 expression and disassembly enhance tumor growth, increase metastatic potential, and shorten overall survival. Using the Clinical Proteomic Tumor Analysis Consortium (CPTAC) stratified by K17 phosphorylation status, we found that increased K17 phosphorylation correlated with worse survival. Mass spectrometry of untreated PDAC patient samples identified a phosphorylation hotspot at serines 10-13, which is conserved across species and type I keratin proteins. We found that K17 phosphorylation, mediated by the PKC/MEK/RSK pathway, led to increased disassembly and nuclear translocation in pancreatic cancer cells. Mice with phosphomimetic mutations at the serine hotspot showed increased metastases and decreased survival compared to wild-type and phosphorylation-resistant K17. Lastly, detergent-soluble nuclear K17 promoted metastasis- related genes in both patient and murine tumors. These findings suggest that disassembly of K17 mediated by phosphorylation at serines 10-13 is sufficient to promote metastases and decrease overall survival in PDAC. This opens the door for further investigation into K17 phosphorylation as a novel therapeutic target to enhance PDAC patient survival, especially in those with more aggressive, chemoresistant subtypes. Citation Format: Deanne E Yugawa, Ryan Kawalerski, Mariana Torrente Gonçalves, Chun-Hao Pan, Robert Tseng, Lucia Roa-Pena, Cindy V Leiton, Luke A Torre-Healy, Taryn Boyle, Sumedha Chowdhury, Natasha T Snider, Kenneth R Shroyer, Luisa F Escobar-Hoyos. Disassembly of embryonic keratin filaments promotes pancreatic cancer metastases [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B079.

Anthocyanin-rich grape pomace extract encapsulated in protein fibers: Colorimetric profile, in vitro release, thermal resistance, and biological activities

Red wine grape pomace is an important source of bioactive compounds with biological activities of interest. Grape pomace extract can be encapsulated in ultrafine fibers using the electrospinning technique. Encapsulation is used to increase stability and protect the phenolic compounds in the extract. In this study, zein fibers were developed for encapsulation of grape pomace extract (0 %, 5 %, 10 %, and 15 % w/w). The extract was evaluated for colorimetric profile, whereas the ultrafine zein fibers carrying the extract were assessed for morphology, loading capacity, in vitro release profile, thermal and thermogravimetric properties, thermal resistance, hydrophilicity, and antioxidant and antimicrobial activities. The grape pomace extract changed color depending on pH, ranging from pink (pH 1) to yellow (pH 13 and 14). The fibers presented a smooth and uniform structure, with diameters of approximately 450 nm and a loading capacity of up to 82 %. The membranes of ultrafine fibers demonstrated hydrophilic behavior, and the in vitro release profile was dependent on the concentration of the added extract. Furthermore, the fibers were observed thermally protect the encapsulated compounds and maintain their antioxidant and antimicrobial activities. These findings indicate that the produced material has potential applications in the development of active and intelligent packaging for the food industry.