Search Results (1,084)

This study optimized the process of extracting protein from black garlic using an alkaline dissolution and acid precipitation method through response surface methodology. The optimal extraction conditions were determined as a solid-to-liquid ratio of 1:50, an extraction time of 100 min, an extraction temperature of 30 °C, and an alkaline extraction pH of 9.0. Under these optimized conditions, the actual black garlic protein (BGP) extraction yield was 12.10% ± 0.21%, and the isoelectric point of the obtained BGP was 3.1. Subsequently, this study extracted black garlic protein under optimal conditions and subjected it to enzymatic hydrolysis using different enzymes (trypsin, pepsin, and their mixed enzymes). The functional characteristics, antioxidant activity, and hypoglycemic activity of black garlic protein before and after enzymatic hydrolysis were compared. Among the hydrolysates, the pepsin hydrolysate (BGPH-P) had the smallest particle size (188.57 ± 1.93 nm) and the highest Zeta potential (−29.93 ± 0.42 mV). Scanning electron microscopy showed that BGPH-P had the smallest and most dispersed particles. Fourier-transform infrared (FTIR) spectroscopy revealed that the dual enzymatic hydrolysis hydrolysate (BGPH-PT) exhibited the most stable structure. Compared to BGP, the hydrolysates demonstrated significantly improved solubility, water-holding capacity, and foaming ability (p < 0.05), while their emulsifying activity, emulsion stability, DPPH radical scavenging capacity, and hypoglycemic activity decreased. In summary, the BGP extracted using the optimized process demonstrated good antioxidant and hypoglycemic activities, while its enzymatic hydrolysate BGPH-P exhibited excellent solubility, water-holding capacity, and emulsifying properties, providing valuable insights for the further development of black garlic protein and its hydrolysates. Full article

Plant protease inhibitors are a ubiquitous feature of plant species and exert a substantial influence on plant stress responses. However, the KTI (Kunitz trypsin inhibitor) family responding to abiotic stress has not been fully characterized in Populus yunnanensis. In this study, we conducted a genome-wide study of the KTI family and analyzed their gene structure, gene duplication, conserved motifs, cis-acting elements, and response to stress treatment. A total of 29 KTIs were identified in the P. yunnanensis genome. Based on phylogenetic analysis, the PyKTIs were divided into four groups (1,2, 3, and 4). Promoter sequence analysis showed that the PyKTIs contain many cis-acting elements related to light, plant growth, hormone, and stress responses, indicating that PyKTIs are widely involved in various biological regulatory processes. RNA sequencing and real-time quantitative polymerase chain reaction analysis showed that KTI genes were differentially expressed under the inverted cutting stress of P. yunnanensis. Transcriptome analysis of P. yunnanensis leaves revealed that PyKTI16, PyKTI18, and PyKTI19 were highly upregulated after inverted cutting. Through the GEO query of Populus transcriptome data, KTI genes played a positive defense role in MeJa, drought, time series, and pathogen stress. This study provided comprehensive information for the KTI family in P. yunnanensis, which should be helpful for the functional characterization of P. yunnanensis KTI genes in the future. Full article

Triploid fish sometimes grow faster and larger than diploids, making them valuable in aquaculture. Their underdeveloped gonads redirect energy from reproduction to muscle growth. This study compared embryonic development and antioxidant responses between allotriploid and hybrid diploid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) after cold shock, aiming to support large-scale allotriploid production. The diploid group had a 99.08% fertilization rate and 82.87% hatching rate, while the triploid group had lower rates (95.71% fertilization, 39.63% hatching, 11.52% deformity). Triploids developed later, with higher incidences of abnormalities and mortality, especially in the gastrula and neuro-embryo stages. Triploid larvae exhibited shortened tails, abnormal yolk sacs, and impaired swimming. Flow cytometry showed triploids that had 1.55 times more DNA and larger red blood cells. Triploids had lower midgut trypsin and lipase levels than diploids (p < 0.05) but similar glucose, liver malondialdehyde, and total cholesterol levels (p > 0.05). However, they had higher liver and spleen lactate dehydrogenase, catalase, and alkaline phosphatase, along with lower spleen malondialdehyde and liver superoxide dismutase (p < 0.05). These findings offer insights into reducing mortality in allotriploid grouper aquaculture, aiding large-scale production efforts. Full article

Whey proteins have anti-fatigue activity, but there are few studies that have reported the ameliorative effects of branched-chain amino acid (BCAA) oligopeptides from whey proteins on fatigue in mice. The purposes of this study were to establish a process for the preparation of BCAA oligopeptides from whey protein and to investigate the anti-fatigue activity of BCAA oligopeptides. Whey proteins were hydrolyzed by trypsin and flavourzyme and purified by ethanol precipitation and reversed-phase high performance liquid chromatography (RP-HPLC). Fraction D’ was found to contain the highest content of BCAAs and a high proportion of low-molecular-weight peptides (<1 kDa; content: 81.48%). Subsequently, mass spectrometry identified 15 BCAA oligopeptides in Fraction D’, including three dipeptides, six tripeptides, two tetrapeptides, and four pentapeptides. In addition, animal experiments showed that BCAA oligopeptides significantly prolonged the residence time on the rod and swimming time of mice. Further studies showed that BCAA oligopeptides remarkably reduced serotonin (5-hydroxytryptamine, 5-HT) synthesis in the brain by down-regulating the plasma-free tryptophan (F-Trp)/BCAA ratio, thereby alleviating fatigue. Therefore, BCAA oligopeptides can be used as an auxiliary functional dietary molecule in functional products to exert anti-fatigue activity by regulating 5-HT synthesis. Full article

Porcine by-products have garnered attention as an excellent material for producing antioxidant peptides; however, understanding the antioxidant characteristics of protein hydrolyzates derived from specific parts remains limited. In this study, we compared the antioxidant properties of protein hydrolyzates derived from major porcine organs (heart, kidney, spleen, liver, and lung) and performed classification based on their antioxidative potential. Their chemical composition exhibited significant variations, with a high protein content ranging from 15.90 to 20.30 g/100 g. Alcalase achieved higher hydrolysis efficiency than trypsin, which induced limited degradation of some proteins, such as porcine serum albumin. The hydrolyzates exhibited superior radical scavenging activities compared to the raw materials, although their reducing power remained unaffected or, in some instances, decreased. Hierarchical and k-mean cluster analyses revealed distinct antioxidant profiles and Alcalase-hydrolyzed kidney and trypsin-hydrolyzed lung hydrolyzates were deemed the most promising candidates, with strong radical scavenging activities and reducing power. Our findings indicate that, even when processed in bulk rather than being obtained from specific parts, porcine by-products can produce hydrolyzates rich in antioxidant peptides through enzymatic hydrolysis. However, selectively processing porcine kidneys with Alcalase and lungs with trypsin is recommended to produce premium products with enhanced and balanced antioxidant properties. Full article

Antioxidants play an important role in maintaining health and enhancing food stability by neutralizing free radicals. This study aimed to extract antioxidant peptides from white-feathered chicken bones through enzymatic hydrolysis, optimize the enzymatic hydrolysis conditions, and further investigate the relevance between the amino acid composition, molecular weight, and antioxidant activity of the resulting chicken bone hydrolysate. Alcalase was the most effective enzyme for hydrolyzing cooked chicken bones compared with papain, pepsin, and trypsin, yielding hydrolysates with the highest DH and ABTS radical scavenging activity. The enzymatic conditions were optimized using single-factor experiments and response surface methodology (RSM). The optimal conditions were a substrate concentration of 10%, an enzyme-substrate ratio of 502.75 U/g, a hydrolysis temperature of 48.48 °C, and a hydrolysis time of 1.13 h. Under these conditions, the ABTS radical scavenging activity reached 83.43%. Amino acid composition analysis revealed that peptides from chicken bones were rich in glycine, glutamic acid, alanine, proline, and aspartic acid, which were associated with antioxidant functions. Among these peptides, those with a molecular weight below 3 kDa exhibited the highest antioxidant effects through membrane filtration. In summary, chicken bone hydrolysate exhibits potent antioxidant activity, nominating them for potential application as natural antioxidants investible in novel functional foods and pharmaceuticals. Full article

To face climate change, searching for alternative crops resistant to drought and heat stress becomes necessary, along with efficient germplasm management. Old landraces well-adapted to local climatic conditions, pests, and pathogens could be used as a source of desired traits. Cowpea (Vigna unguiculata L. Walp.), grown mainly in the tropical and subtropical areas, presents superior drought and heat stress adaptation compared to other legumes. Limited information is available on field performance and nutrient qualities of cowpea landraces originating from southern Bulgaria. The aim of the present study was to compare in field conditions and their impacts on plant performance, yield, and the seed biochemical composition of Bulgarian cowpea accessions, including fourteen landraces and one variety. Higher-yielding, earlier-maturing accessions were discerned. Among the landraces studied, B1E0103 was the most productive under the agro-climatic conditions in Sadovo, central Bulgaria; BOE0035 had the earliest maturity. The seed moisture content was 11.5 ± 0.3%, and the energy value was 347.9 ± 1.2 kcal/100 g. The crude protein content varied from 22.5 to 27%, the lipids were 1.6–2.55%, the carbohydrates were 56.5–61.4%, ash was 3.8–4.3%, dietary fibers were 3.1–4.5%, tannins were 16–22%, phenols were 1.3–4.4 mg/g, flavonoids were 1.85–3.7 mg/g, and the trypsin-inhibiting activity was 0.7–2.5 units/mg FW, with the lowest in BOE0010, the variety “Hrisi”, and B1E0103 and the highest in B0E0035, A9E1230, and A8E0562. Landraces are promising genetic material for future research and breeding purposes. Full article

Rhodopseudomonas palustris (RP) are known anaerobic bacteria with probiotic properties containing several bioactive compounds and enzymes that benefit aquatic animals. However, studies on the use of RP on aquatic animal species are limited. This study investigated the effects of dietary supplementation with RP formulation on the growth, non-specific immunity, and disease resistance of juvenile ivory shells (Babylonia areolata). The experiment was conducted for 8 weeks, with B. areolata fed a control diet (RP0) and four diets containing four different RP formulations, with doses of 1 (RP1), 5 (RP2), 10 (RP3), and 20 (RP4) g/kg, respectively. Higher levels of R. palustris in the formulation led to increased final weight, weight gain, and specific growth rate in B. areolata. The crude protein content was significantly higher in the RP4 group compared to the RP0 group. However, there was no significant difference in the crude lipid content. Higher levels of R. palustris in the RP4 formulation group increased the trypsin and lipase activities. Dietary supplementation with RP significantly increased the total antioxidant capacity, superoxide dismutase, and catalase activities and decreased the malondialdehyde content in B. areolata. Acid phosphatase and alkaline phosphatase activities were significantly increased in the RP4 group compared to the RP0 group. Dietary RP significantly increased the expression levels of antioxidant-related (superoxide dismutase, Cu/Zn-superoxide dismutase, glutathione S-transferase A-like, ferritin) and immune-related (acid phosphatase, cytochrome c) genes. Higher levels of R. palustris in the formulations RP3 and RP4 increased the survival rate of B. areolata challenged with Vibrio parahaemolyticus. These findings indicate that R. palustris preparation could improve growth performance, muscle composition, and digestive capacity and may act as an immune booster for preventing disease in B. areolata. Full article

α-amylase can effectively inhibit the activity of digestive enzymes and alter nutrient absorption. The impact of ovum hydrolysates of sea cucumbers on α-amylase activity was investigated in this study. The protein hydrolysates generated using different proteases (pepsin, trypsin, and neutral protease) and molecular weights (less than 3000 and more than 3000) were investigated. The results showed that all three different hydrolysates demonstrated calcium-chelating activity and induced a fluorescence-quenching effect on α-amylase. The sea cucumber ovum hydrolysate with a molecular weight of less than 3000 Da, isolated using trypsin, showed the most effective inhibitory effect on α-amylase, with an inhibition rate of 53.9%, and the inhibition type was identified as mixed forms of inhibition. In conclusion, the generation and utilization of protein hydrolysates from sea cucumber ovum as a functional food ingredient could be a potential approach to add value to low-cost seafood by-products. Full article

Numerous studies have explored alternative protein sources to fishmeal (FM) to enhance fish diets, yet limited research exists on their effects on maturation. This study assessed the impact of replacing FM with soy protein concentrate (SPC) supplemented with lysine and methionine on growth and gonadal development in olive flounder (Paralichthys olivaceus). Three diets were tested: a control (Con) diet with 60% FM and two diets replacing FM with 25% (LF1) and 50% (LF2) SPC. Fish were fed to apparent satiation twice daily for 12 months. Growth performance and feed intake were not significantly different between groups. However, the gonadosomatic index varied with diet. Muscle composition and amino acid levels were similar across treatments, though n-3 fatty acids were higher in Con. Spermatogonia was increased, and spermatogenesis was impaired in SPC groups. At 12 months, oocytes in Con diets had absorbed yolk globules, whereas this was absent in SPC groups. Growth-related genes in the brain (growth hormones and insulin-like growth factor) were increased with higher SPC, while follicle-stimulating and luteinizing hormones decreased. Estrogen receptor α levels were elevated in SPC groups. Vitellogenin gene expression in gonads was highest in Con, while liver expression peaked in LF2. The expression of digestive enzymes, chymotrypsin2, and trypsin2 was highest in LF2, while lipase genes were lower. In summary, up to 50% FM replacement with SPC, with amino acid supplementation, supported growth performance and muscle composition without adverse effects on growth in olive flounder but influenced gonadal development. Full article

Rice-fish farming is an ancient and enduring aquaculture model in China. This study aimed to assess the variations in digestive enzymes, antioxidant properties, glucose metabolism, and nutritional content between Carassius auratus reared in paddy fields and ponds. Notably, the levels of amylase and trypsin in C. auratus from rice paddies were considerably higher compared to those from ponds. Additionally, the hepatic catalase (CAT) activity in fish from paddy (2.45 ± 0.16 U/mg) exceeded that of their pond counterparts (2.27 ± 0.25 U/mg). Regarding glucose metabolism, the activities of key enzymes such as Na+/K+-ATPase (NKA) (paddy: 82.45 ± 6.11 U/g; pond: 78.53 ± 7.18 U/g), hexokinase (HK) (paddy: 9.55 ± 0.58 U/g; pond: 8.83 ± 0.72 U/g), glucokinase (GK) (paddy: 4.09 ± 0.21 IU/g; pond: 3.44 ± 0.33 IU/g), glucose-6-phosphatase (G6Pase) (paddy: 85.71 ± 4.49 IU/g; pond: 79.12 ± 9.34 IU/g), and glucose-6-phosphate dehydrogenase (G6PDH) (paddy: 47.23 ± 3.22 U/g; pond: 42.31 ± 4.93 U/g) were significantly elevated in rice paddy-cultured fish compared to those in ponds. Conversely, phosphor-pyruvate kinase (PK) (paddy: 418.15 ± 31.89 U/g; pond: 570.16 ± 56.06 U/g) activity was markedly reduced in the paddy group. Hepatic glycogen content (paddy: 15.70 ± 0.98 ng/g; pond: 14.91 ± 1.24 ng/g) was also substantially higher in fish from paddy, although no significant differences in muscle glycogen content (paddy: 7.14 ± 0.59 ng/g; pond: 6.70 ± 0.52 ng/g) were observed between the two environments. In terms of nutritional composition, fish raised in paddy exhibited higher crude protein (paddy: 18.46 ± 0.47 g/100 g muscle; pond: 15.57 ± 0.25 g/100 g muscle) and crude ash (paddy: 1.19 ± 0.02 g/100 g muscle; pond: 0.97 ± 0.02 g/100 g muscle) than those in ponds, whereas the crude fat (paddy: 0.87 ± 0.04 g/100 g muscle; pond: 1.66 ± 0.04 g/100 g muscle) was notably lower in paddy fish. Furthermore, fish from rice paddies had a greater total content of monounsaturated fatty acids (MUFA) (paddy: 4.25 ± 0.24 g/100 g muscle; pond: 6.73 ± 0.27 g/100 g muscle), non-essential amino acids (NEAA) (paddy: 9.04 ± 0.3 g/100 g muscle; pond: 7.19 ± 0.21 g/100 g muscle), and delicious amino acids (DAA) (paddy: 7.11 ± 0.2 g/100 g muscle; pond: 5.45 ± 0.19 g/100 g muscle) compared to those from pond cultures. These findings suggest that rice-fish co-culture systems can yield healthier and more environmentally sustainable aquatic products by improving feed digestion and optimizing nutrient metabolism. Full article

Five isonitrogenous and isolipidic diets (Diet 1–Diet 5, with Diet 1 as the control) were formulated to replace 0%, 20%, 40%, 60%, and 80% of fishmeal with American cockroach residue. Juvenile Cyprinus carpio (initial body weight approximately 74 g) were randomly assigned to these diets for a 10-week feeding trial. The Diet 3 group (40% replacement) showed significantly higher final body weight, weight gain rate, specific growth rate, and protein efficiency ratio compared to other groups. No significant differences were observed in crude protein, ash, and total amino acid content across the diets. Groups fed Diet 1 and Diet 2 exhibited higher intestinal trypsin, lipase, α-amylase, and hepatic trypsin activities. Serum triglyceride (TG) levels were highest in the Diet 5 group. Hepatic aspartate aminotransferase (AST) activity was significantly lower in the Diet 3 and Diet 5 groups compared to Diet 1. Serum urea nitrogen levels followed a non-linear trend, initially increasing, then decreasing, and rising again with increasing fishmeal replacement. No significant differences were found in serum total protein (TP) levels among the dietary groups. Intestinal villus number, muscle layer thickness, villus height, villus width, and crypt depth remained consistent across groups. However, goblet cell numbers were significantly reduced at the 60% replacement level, which could impair intestinal barrier function. Diet 3 showed higher serum and hepatic total superoxide dismutase (T-SOD) activity, while Diet 2 had the highest hepatic total antioxidant capacity (T-AOC) activity. Hepatic malondialdehyde (MDA) levels were lowest in the Diet 2 and Diet 5 groups. Immunoglobulin M (IgM) levels showed an increasing trend with higher fishmeal replacement levels. In conclusion, replacing fishmeal with American cockroach residue did not adversely affect growth performance or body composition in juvenile C. carpio. Substituting 20–40% of fishmeal with American cockroach residue enhanced antioxidant capacity and immune function in juvenile C. carpio. Full article

Cytophaga is a genus of Gram-negative bacteria occurring in soil and the gut microbiome. It is closely related to pathogenic Flavobacterium spp. that cause severe diseases in fish. Cytophaga strain L43-1 secretes cytophagalysin (CPL1), a 137 kDa peptidase with reported collagenolytic and gelatinolytic activity. We performed highly-confident structure prediction calculations for CPL1, which identified 11 segments and domains, including a signal peptide for secretion, a prosegment (PS) for latency, a metallopeptidase (MP)-like catalytic domain (CD), and eight immunoglobulin (Ig)-like domains (D3–D10). In addition, two short linkers were found at the D8–D9 and D9–D10 junctions, and the structure would be crosslinked by four disulfide bonds. The CPL1 CD was found closest to ulilysin from Methanosarcina acetivorans, which assigns CPL1 to the lower-pappalysin family within the metzincin clan of MPs. Based on the structure predictions, we aimed to produce constructs spanning the full-length enzyme, as well as PS+CD, PS+CD+D3, and PS+CD+D3+D4. However, we were successful only with the latter three constructs. We could activate recombinant CPL1 by PS removal employing trypsin, and found that both zymogen and mature CPL1 were active in gelatin zymography and against a fluorogenic gelatin variant. This activity was ablated in a mutant, in which the catalytic glutamate described for lower pappalyins and other metzincins was replaced by alanine, and by a broad-spectrum metal chelator. Overall, these results proved that our recombinant CPL1 is a functional active MP, thus supporting the conclusions derived from the structure predictions. Full article

Thus far, no manufacturing process able to support industrialization has been reported for the recombinant human brain-derived neurotrophic factor (rhBDNF). Here, we described the setup of a new protocol for its production in Escherichia coli (E. coli) and its purification to homogeneity. A synthetic gene, codifying for the neurotrophin precursor, was inserted into an E. coli expression vector and transformed into BL21 (DE3) strain. The recombinant protein accumulates, at high yields, into inclusion bodies. With the developed strategy, more than 50% of the precursor can be refolded. The protein is successively digested by trypsin and the rhBDNF mature form is finally purified by two additional chromatographic steps If the wild-type precursor can be efficiently obtained by the proposed methodology, its pro-peptide remotion, through enzymatic digestion, is however problematic. To circumvent this difficulty, the precursor hinge region, containing the natural furin recognition site, was engineered to be more specifically cleaved by trypsin. Notwithstanding the substitution of three residues in the pro-region carboxyterminal, the precursor correctly refolds and is efficiently cleaved to generate a biologically active mature rhBDNF. This efficient high-yield process fills the current need of a scalable protocol to produce GMP-grade material and unlocks the rhBDNF employment in future clinical investigations. Full article

Malondialdehyde (MDA) is a reactive carbonyl compound produced through lipid peroxidation during feed storage, which poses a significant threat to fish health. This study aimed to evaluate the effects of dietary MDA on the growth rate, gastrointestinal health, and muscle quality of striped catfish (Pangasianodon hypophthalmus). A basal diet (M0) containing 34% crude protein and 10.5% crude lipid was formulated. Each group was sprayed with malondialdehyde solution (0, 5, 10, 20, 40, and 80 mg/kg, on dietary crude lipid basis; 0, 0.53, 1.07, 2.13, 4.26, and 8.52 mg/kg, on dietary basis) before feeding, respectively. Each diet was randomly assigned to triplicates of 30 striped catfish (initial weight 31.38 g) per net cage. After 8 weeks, dietary inclusion of MDA regardless of level significantly depressed the growth rate and feed utilization. The extent of structural damage to the gastrointestinal tract increased progressively with increasing dietary MDA levels. The extent of damage to the intestinal biological barrier (intestinal microbial structure), chemical barrier (trypsin, lipase, amylase, and maltase activity), physical barrier (zonula occludent-2, occludin, claudin 7α, and claudin 12 relative expression), and immune barrier (contents of complement 4, complement 3, immunoglobulin M, and lysozyme activity) was dose-related to dietary MDA. Moreover, a linear decline in the activities of intestinal antioxidant enzymes (catalas, superoxide dismutase, et al.) and anti-inflammatory factor (transforming growth factor beta1, interleukin 10) relative expression was noted alongside an increase in dietary MDA content. In contrast, the relative expression levels of intestinal inflammatory factor (interleukin 8, transcription factor p65, tumor necrosis factor alpha) relative expression displayed an opposing trend. Additionally, dietary MDA exerted a linear influence on muscle color and texture characteristics. In conclusion, high doses of MDA (5–80 mg/kg) reduced the growth performance of striped catfish, attributed to linear damage to the gastrointestinal tract, a linear decrease in antioxidant function, and the occurrence of an inflammatory response. High doses of MDA (>40 mg/kg) were observed to significantly increase dorsal muscle b-value and induce muscle yellowing. Full article