Enzymes Trypsin Research Articles

Structural analysis and inhibition capacity of dioscorin protein yam: Theoretical study by molecular docking and dynamic simulations.

Proteases such as trypsins in the gut of Spodoptera frugiperda are responsible for breaking down dietary proteins into amino acids necessary for insect growth and development. In this study, we characterized the insecticidal potential of dioscorin, the storage protein of yam (Dioscorea alata), using molecular docking and molecular dynamics simulations to determine the interactions between trypsin enzymes and the protein inhibitor dioscorin. To achieve this, we used the three-dimensional structures of the trypsin-like digestive enzymes of S. frugiperda, a pest of corn and cotton, as receptors or target molecules. We performed protein-protein docking using Cluspro software, estimation of the binding free energy, and information on the dynamic and time-dependent behavior of dioscorin-trypsin complexes using the NAMD package. Our computational analysis showed that dioscorin can bind to the digestive trypsins of S. frugiperda, as confirmed by the affinity energy values (-1022.4 to -1236.9), stability of the complexes during the simulation trajectory, and binding free energy values between -57.3 and -66.9 kcal/mol. Additionally, dioscorin uses two reactive sites to bind trypsin, but the largest contribution to the interaction energy is made by amino acid residues between amino acid backbone positions 8-14 by hydrogen bonds, hydrophobic, and Van der Waals (VdW) interactions. VdW is the energy that makes the greatest contribution to the binding energy. Collectively, our findings demonstrate, for the first time, the binding capacity of the yam protein dioscorin to the digestive trypsin of S. frugiperda. These promising results suggest a possible bioinsecticide action of dioscorin.

Application of enzymatically treated Artemisia annua L. on adult grass carp (Ctenopharyngodon idella): Improved growth performance, intestinal antioxidant capacity and apical junctional complex

The present study evaluated the effects of enzymatically treated Artemisia annua L. (EA) on the growth performance, intestinal antioxidant capacity, and apical junctional complex (AJC) of adult grass carp. In this experiment, 375 healthy grass carp (initial body weight 673.96 ± 1.24 g) were selected and randomly divided into 5 treatments, and fish in each group were fed diets with different levels of EA (0, 400, 800, 1200, and 1600 mg/kg) 9 weeks. The results showed that compared with the control group (0 mg/kg EA diet), the EA supplementation in the diet increased the percentage of weight gain (PWG), specific growth rate (SGR), and feed intake (FI) (P < 0.05), indicating that dietary EA supplementation improved the growth performance of adult grass carp. The dietary EA supplementation also enhanced the digestion and absorption ability of adult grass carp, which might be reflected by improving the activities of hepatopancreas digestive enzymes (trypsin, chymotrypsin, lipase, and amylase) and intestinal brush border enzymes (alkaline phosphatase, Na+/K+-ATPase, and γ-glutamyl transpeptidase), but EA did not affect the creatine kinase enzyme activity. Meanwhile, we explored the effect of dietary EA addition on the structural integrity of the grass carp intestine. We observed that dietary EA supplementation improved the antioxidant capacity of the intestine which be reflected by increasing the activities levels of superoxide dismutase (SOD) and catalase (CAT), which might be related to the binding protein Keap1a (not Keap1b)/ NF-E2-related factor-2 (Nrf2) signaling pathway. In addition, dietary EA supplementation enhanced the integrity of AJC by increasing the mRNA levels of intestinal tight junction proteins (TJs) (except claudin 11, claudin 12, claudin 15a) and adhere junction proteins (AJs) (E-cadherin, α-catenin, β-catenin, nectin, and afadin), which might be related to the Rho family GTPases (RhoA)/ Rho-associated protein kinase (ROCK)/ myosin light chain kinase (MLCK) signaling pathway. Collectively, dietary EA supplementation improved growth performance, digestion and absorption ability, and intestinal structural integrity in grass carp, which were associated with the activation of related signaling pathways and regulatory factors. Finally, by the growth indicator percent weight gain (PWG) and intestinal oxidative damage index protein carbonyl (PC), the optimum amounts of EA supplementation of adult grass carp (673–1726 g) were assessed to be 808.09 and 730.38 mg/kg diet, respectively.

The endoplasmic reticulum acetyl-CoA transporter AT-1 plays a role in the protective unfolded protein response in the exocrine pancreas

Pancreatic acinar cells are responsible for the synthesis and secretion of digestive enzymes. In order to sustain high rates of secretory protein production, acinar cells rely on adaptive mechanisms to mitigate endoplasmic reticulum (ER) stress and maintain secretory homeostasis. The adaptive unfolded protein response (UPR), mediated by the IRE1-XBP1s axis, is essential for acinar function and protects against cellular injury. Recent work has demonstrated that the ER acetyl-CoA transporter, AT-1, is necessary for nascent secretory protein acetylation and export out of the ER and is regulated by IRE1-XBP1s. Furthermore, AT-1 is rapidly downregulated during experimental pancreatitis. To investigate the role of AT-1 in exocrine pancreas function, we generated inducible, acinar-specific AT-1 knockout mice (Ela-Cre AT-1-/-). Loss of AT-1 produced a chronic pancreatitis phenotype characterized by inflammation, immune cell infiltration, tissue fibrosis, and aberrant intracellular activation of the proteolytic digestive enzyme trypsin. Despite the histological and biochemical dysfunction observed, Ela-Cre AT-1-/- mice grow normally, have typical lifespans, and do not lose pancreatic mass. Interestingly, XBP1s expression is significantly upregulated in Ela-Cre AT-1-/- and may confer a protective effect with loss of AT-1. Our data suggests a role for AT-1 in the IRE1-XBP1s axis and highlights the previously undescribed role of protein acetylation in exocrine pancreas physiology. Given the numerous potential downstream effects of dysregulated acetyl-CoA transport, this model will advance our understanding of pancreatic function and disease. NIH This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of Soybean Trypsin Inhibitor on Pancreatic Oxidative Damage of Mice at Different Growth Periods.

The bioactive components in soybeans have significant physiological functions. However, the intake of soybean trypsin inhibitor (STI) may cause metabolic disorders. To investigate the effect of STI intake on pancreatic injury and its mechanism of action, a five-week animal experiment was conducted, meanwhile, a weekly monitor on the degree of oxidation and antioxidant indexes in the serum and pancreas of the animals was carried out. The results showed that the intake of STI had irreversible damage to the pancreas, according to the analysis of the histological section. Malondialdehyde (MDA) in the pancreatic mitochondria of Group STI increased significantly and reached a maximum (15.7 nmol/mg prot) in the third week. Meanwhile, the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), trypsin (TPS), and somatostatin (SST) were decreased and reached minimum values (10 U/mg prot, 87 U/mg prot, 2.1 U/mg prot, 10 pg/mg prot) compared with the Group Control. The RT-PCR results of the expression of SOD, GSH-Px, TPS, and SST genes were consistent with the above. This study demonstrates that STI causes oxidative structural damage and pancreatic dysfunction by inducing oxidative stress in the pancreas, which could increase with time.

Trypsin-Based Chemoenzymatic Assay for Detection of Pollutants and Safety Assessment of Food Additives

Chemoenzymatic assay systems are widely used to detect toxicants in various samples, including food and environment specimens. These methods are based on the ability of various types of toxicant to specifically inhibit/activate the functions of individual enzymes or enzyme systems. The present study examines the possibility of using the proteolytic enzyme trypsin as a specific marker to detect protease inhibitors in different samples. The study shows that trypsin activity is not affected by various heavy metals, pesticides, or quinones at levels considerably greater than their maximum allowable concentrations (MACs) in water bodies. At the same time, the IC50 value for the food preservative potassium sorbate (E202) is 15 mg/L, which is substantially lower than its acceptable daily intake (ADI). The quenching of trypsin fluorescence in the presence of potassium sorbate suggests that inhibition could occur due to the binding of the preservative to the enzyme in the region adjacent to the active center. The trypsin was immobilized in starch gel to ensure its stability in the enzyme inhibition based assay. Single-use reagents were prepared as dry starch disks that could be stored over long periods. Their sensitivity to copper (II) chloride, potassium sorbate, and chromium (III) chloride was similar to the sensitivity of the free trypsin.

Production and purification of fucoxanthins and β-carotenes from Halopteris scoparia and their effects on digestive enzymes and harmful bacteria

ABSTRACT Algae constitute a significant part of marine biodiversity. They represent a renewable source of bioactive metabolites from drug development and therapeutic fields. Fucoxanthin and β-carotene from the brown macroalgae Halopteris scoparia, were extracted using conventional organic solvent extraction, then purified, to homogeneity, based on various chromatographic principles. Their effects on digestive enzymes and harmful bacteria were investigated. The capacities of both purified pigments to inhibit α-amylase and trypsin enzymes were evaluated. Purified fucoxanthin and β-carotene exhibited interesting α-amylase inhibition activities, with IC50 of 300 and 500 µg/mL, respectively. Moreover, trypsin inhibition activities were detected using purified these two pigments. The antibacterial potential of the purified pigments was evaluated. β-carotene showed to be a great antibacterial natural compound against gram-positive and gram-negative bacteria such as Listeria monocytogenes, Staphylococcus aureus and Salmonella enterica with Minimal Inhibitory Concentration (MIC) of about 0.225, 0.1125, 0.225 µg/mL, respectively. Those findings are in favor of the exploitation of H. scoparia pigments in therapeutic fields as an antidiabetic source directly by the inhibition of α-amylase and trypsin as well as antibacterial agents against gastrointestinal infections.

Formation and Characterization of Self-Assembled Rice Protein Hydrolysate Nanoparticles as Soy Isoflavone Delivery Systems

In this study, soy isoflavones-loaded nanoparticles were prepared using rice proteins (RPs) hydrolyzed by four types of enzyme (alcalase, neutrase, trypsin, and flavorzyme). After optimizing the preparation conditions, the encapsulation efficiency (EE) of the nanoparticles ranged from 61.16% ± 0.92% to 90.65% ± 0.19%. The RPs that were hydrolyzed by flavorzyme with a molecular weight of <5 KDa showed better characters on the formation of nanoparticles, and the formed nanoparticles had the highest EE and loading capacity (9.06%), the smallest particle size (64.77 nm), the lowest polymer dispersity index (0.19), and the lowest zeta potential (-25.64 mV).The results of Fourier transform ion cyclotron resonance, X-ray diffraction, and fluorescence spectroscopy showed that the nanoparticles were successfully encapsulated. The study of interaction showed that the formation of nanoparticles may depend mainly on hydrogen bonds, but other interactions, such as hydrophobic interactions and electrostatic interactions, cannot be ignored. After encapsulation, the pH stability, temperature stability, ionic stability, and oxidation resistance of the nanoparticles were enhanced. Moreover, the in vitro release experiment showed that the encapsulated nanoparticles had a certain protective effect on soybean isoflavones. In summary, rice protein hydrolysates are promising carriers for soybean isoflavones.

Physicochemical, Microbiological, and Sensory Properties of Set-Type Yoghurt Supplemented with Camel Casein Hydrolysate

The microbiological, rheological, and sensory properties of set-type yoghurt were investigated in the presence of camel and cow casein hydrolysates produced by the action of trypsin enzymes. The hydrolysates significantly decreased the fermentation and coagulation time of the yoghurt production. The rate of pH decrease was significantly (p &lt; 0.05) higher in samples treated with cow casein hydrolysate in comparison with control samples. Compared with the control, the cell growth of the yoghurt culture increased with the supplementation of the casein hydrolysate. Moreover, the survival of lactic acid bacteria (LAB) was enhanced by the addition of hydrolysates. The fortification of cow milk with camel and cow casein hydrolysates contributed to a significant improvement of the rheological and sensory properties of yoghurt. In conclusion, camel and cow casein hydrolysate could be used as a supplement in set-type yoghurt production with a potential beneficial effect on fermentation time, survival of total bacterial count, and overall acceptability.

Postprandial pattern of digestive enzymes and protein turnover in meagre (Argyrosomus regius) juveniles.

After a meal, a sequence of physiological changes occurs in animals in response to digestion, absorption and assimilation of the ingested nutrients. These processes are very important for the aquaculture sector since they will define the efficiency by which food is converted into growth, thus contributing to reduce the production costs and also undigested food in the effluents. Here we investigated the activity of digestive enzymes in the midgut and the protein degradation systems following a single meal to define postprandial patterns of action in hepatic and muscle tissues of meagre juveniles. Fish were fed with a single meal followed by a period of 24h without feed. The activity of several digestive enzymes (α-amylase, trypsin, aminopeptidase, alkaline and acid phosphatases) plus the analysis of key players of the ubiquitin-proteasome (UPS) and autophagy-lysosomal (ALS) systems were examined just before feeding (0h, basal point) and 2, 4, 6, 8 and 24h after food ingestion. Digestion was activated around 4h after food ingestion and nutrients available for protein degradation 2h later. This work provided information about the short-term physiological effects induced by a single meal to support scientists' decision when planning a specific study involving digestion and protein degradation, and also to fish farmers on how to better manage feeding protocols when producing A. regius juveniles. Our results suggested that meagre juveniles, under the experimental conditions used, can be fed every 4h, time when digestion starts, however further studies should be addressed to find the optimal feeding regime for this juvenile species.

ERRATUM: Evaluation of the Anti-inflammatory, Antioxidant, and Protease Inhibitory Activity of the Crude Methanol Extract of Portulaca oleracea

Protease inhibitors have considerable applications in biomedicine, biotechnology, and therapy. The aim of the study was to evaluate the methanol crude extracts of aerial portions of Portulaca oleracea (P. oleracea) for anti-inflammatory, antioxidant, and protease inhibitor activities, and to evaluate their inhibitory action against various therapeutically significant proteases. A modified colorimetric assay was used to analyze the protease inhibitors on trypsin and other therapeutic enzymes. P. oleracea crude leaf extract exhibited 79.92% antioxidant and 75% anti-inflammatory activity. Analysis of the effects of crude P. oleracea extract on the values of enzyme kinetics (Km, Vmax) was determined by Lineweaver-Burk reciprocal plot. It was found that the extract exhibited a potent inhibitory effect on the Vmax (µmole/min) of the chymotrypsin 26.0, trypsin 18.0, papain 8.33, and elastase 10.0, when compared to control 41.0, 73.0, 11.11, and 20.3, respectively. While no effect on Km except for elastase which was decreased from 0.026 mM for the control to 0.01 mM. It was found that this effect showed a powerful inhibition in a different way. There is a mixed non-competitive inhibition on elastase as well as pure non-competitive inhibition on chymotrypsin, trypsin, and papain. The crude extract contained 53.3%, 55.7%, 14.9%, and 26.9%, respectively, of protease inhibitors for the therapeutic protease enzymes trypsin, papain, chymotrypsin, and elastase. Therefore, trypsin, papain, chymotrypsin, and elastase have been inhibited by the crude extract of P. oleracea. Characterization of the crude extract indicated potent anti-inflammatory and antioxidant effects.

Assessment of zootechnical parameters, intestinal digestive enzymes, haemato-immune responses, and hepatic antioxidant status of Pangasianodon hypophthalmus fingerlings reared under different stocking densities

A 3-month experiment was designed to investigate the effects of different stocking densities on growth, stress markers, intestinal digestive enzymes, hepatic antioxidant biomarkers, serum immunity, and survivability of striped catfish, Pangasianodon hypophthalmus. The relationship between fish stocking densities and water quality parameters was also assessed. Healthy fish (n = 1260 individuals, 17.52 ± 0.20 g) were raised in twelve fiberglass tanks. Triplicate fish groups with stocking densities of 60, 90, 120, or 150 fish per 1 m3 were designed, further referred to as SD60, SD90, SD120, and SD150 groups. Fish feeding was done using a commercially purchased well-balanced diet three times per day with a feeding rate of 3% of the wet fish weight. Results revealed that un-ionized ammonia, nitrite, and pH were significantly elevated, and dissolved oxygen levels were decreased significantly with increasing the stocking densities. The survival rates and growth significantly decreased with increasing fish stocking densities. The intestinal lipase, protease, trypsin, and amylase enzymes decreased significantly (P < 0.05) along with increased stocking densities. Moreover, significant decreases were noticed in total protein, lysozyme activity, and globulin levels when the stocking density was higher than 60 fish/m3. Conversely, serum stress biomarkers (such as blood glucose and cortisol), transaminases, alkaline phosphatase, and blood urea nitrogen were significantly elevated with increasing stocking densities. Hepatic CAT, SOD, and T-AOC were decreased; meanwhile, hepatic MDA levels were significantly increased, together with the stocking rates. In the end, we found that the SD150 group recorded the lowest growth rates, immune responses, and antioxidant capacity and the highest stress markers as blood glucose and cortisol. In this context, we can conclude that the stocking 60 fish/m3 resulted in better growth, survival, immunity, antioxidant status, and overall performances of striped catfish.Graphical

Effects of Dietary Rare Earth Chitosan Chelate on Performance, Egg Quality, Immune and Antioxidant Capacity, and Intestinal Digestive Enzyme Activity of Laying Hens.

Rare earth chitosan chelate salt (RECC) is a potential feed additive and is a product of the chelation effect between rare earth ions and chitosan. This research study aims to explore the effects of dietary RECC on performance, egg quality, intestinal digestive function, and the immune and antioxidant capacity of laying hens in the late phase of production. A total of 360 56-week-old Dawu Jinfeng laying hens were randomly allotted into four treatment groups with six replicates per treatment and 15 birds per replicate. The laying hens were fed the basal diet supplemented with, respectively, 0 (control: CON), 100 (R1), 200 (R2), and 400 (R3) mg/kg for 8 weeks. Dietary RECC significantly improved average daily feed intake (ADFI) and average daily egg yield in both linear and quadratic manner (p < 0.05). In addition, albumen height and HU were improved significantly (p < 0.05) in a dose-dependent manner of RECC. In addition, a significant decrease (p < 0.05) in serum TP, IgA, and MDA for the R1 group and IgG in the R2 group were notable, while the increase in serum TP and decrease in T-AOC were found for R3 dietary group compared to CON (p < 0.05). The level of intestinal IL-2 and TNF-α was decreased by dietary RECC (p < 0.01). The activities of the digestive enzyme (α-Amylase, lipase, and Trypsin) showed a quadratic change with an increase and then decrease in response to increasing dose of RECC, 200 mg/kg RECC significantly increased the activity of lipase and Trypsin (p < 0.01). Supplementation of dietary RECC at low doses compared to higher doses impacted positive effects on the antioxidant capacity and immune function (p < 0.05). The utilization of RECC as a feed additive in the diet of aged laying hens exerted beneficial effects on egg production, albumen quality, humoral immunity, inflammatory response, and activity of digestive enzymes. Thus, the regulation of antioxidant capacity and duodenal function via increased enzyme activity and immune and inflammatory response were critical to the improvement of laying performance and egg quality in aged hens. The optimal supplemental dose is 100-200 mg/kg.

Effects of Panax notoginseng Water Extract on Immune Responses and Digestive Enzymes in White Shrimp Litopenaeus vannamei

Panax notoginseng (Burk) F. H. Chen is a traditional Chinese herbal medicine commonly used in clinical applications. This study examined the effects of the Panax notoginseng water extract (PNWE) on the immune responses and digestive enzyme activity of Litopenaeus vannamei (L. vannamei). The PNWE (50, 100, and 200 μg (g shrimp)-1) was injected into L. vannamei to analyze the immune response parameters, including the total haemocyte count (THC), granular haemocytes (GC), semi-granular haemocytes (SGC), hialin haemocyte (HC), the respiratory burst (RB), the phagocytic ratio (PR), the phagocytic index (PI), and phenoloxidase (PO). We evaluated the activity of the intestinal digestive enzymes (trypsin, chymotrypsin, amylase, and lipase), the histopathology, and the intestine Vibrio numbers. The results showed that different concentrations of the PNWE significantly increased THC, GC, SGC, PO and RB activity, the PR, and the PI of L. vannamei while reducing the HC. In addition, the PNWE also significantly increased the chymotrypsin, trypsin, and amylase activity of L. vannamei. Furthermore, 50 µg (g shrimp)-1 of PNWE regulated the lipase activity. Additionally, different concentrations of the PNWE significantly reduced the Vibrio numbers in the intestine without damaging the hepatopancreas and intestine tissues. These results indicate that the PNWE improves the immune responses of L. vannamei by increasing the haemocyte count and regulating intestinal digestive enzymes.

Towards Electrochemical Sensor Based on Molecularly Imprinted Polypyrrole for the Detection of Bacteria-Listeria monocytogenes.

Detecting bacteria-Listeria monocytogenes-is an essential healthcare and food industry issue. The objective of the current study was to apply platinum (Pt) and screen-printed carbon (SPCE) electrodes modified by molecularly imprinted polymer (MIP) in the design of an electrochemical sensor for the detection of Listeria monocytogenes. A sequence of potential pulses was used to perform the electrochemical deposition of the non-imprinted polypyrrole (NIP-Ppy) layer and Listeria monocytogenes-imprinted polypyrrole (MIP-Ppy) layer over SPCE and Pt electrodes. The bacteria were removed by incubating Ppy-modified electrodes in different extraction solutions (sulphuric acid, acetic acid, L-lysine, and trypsin) to determine the most efficient solution for extraction and to obtain a more sensitive and repeatable design of the sensor. The performance of MIP-Ppy- and NIP-Ppy-modified electrodes was evaluated by pulsed amperometric detection (PAD). According to the results of this research, it can be assumed that the most effective MIP-Ppy/SPCE sensor can be designed by removing bacteria with the proteolytic enzyme trypsin. The LOD and LOQ of the MIP-Ppy/SPCE were 70 CFU/mL and 210 CFU/mL, respectively, with a linear range from 300 to 6700 CFU/mL.

Partial dietary fishmeal replacement with mixture of plant protein sources supplemented with exogenous enzymes modify growth performance, digestibility, intestinal morphology, haemato-biochemical and immune responses for Nile tilapia, Oreochromis niloticus

For the aquaculture sector, expanding the amount of plant proteins substituting fish meal (FM) is favorable. This study was conducted to evaluate the properties of diets containing a blend of plant protein sources (cotton seed meal, sunflower meal and jojoba (CSJ)) instead of FM and supplemented with a mixture of exogenous enzymes on the growth performance, intestinal morphology, blood indices, activity of endogenous and digestibility also, immune response of Nile tilapia, Oreochromis niloticus. Three groups of the experimental diet (29.5% crude protein) and (18.76 MJ kg −1 gross energy) were performed. The first group CSJ1 was (FM: CSJ = 2:1), the second group diet CSJ2 was (FM: CSM = 2:2) and the third CSJ3 was (FM: CSJ = 2:1), the replaced was based on content of protein. All groups of diets were supplemented with mixture of enzymes (Protease, pepsin, trypsin, xylanase and amylase) at 0 and 0.5 g kg −1 diet therefore six diet was formulated. Fingerlings (6.30 ± 0.09 g) were randomly allocated into eighteen plastic tank (450 L capacity) in triplicate per each treatment (25 fish/ treatment) for 90 days. After 90-days of the feeding trial, results indicated that the highest wight gain and best FCR, higher (P < 0.05) activity of trypsin and lipase, apparent digestibility coefficient of nutrients were detected in fish fed diet of FM: CSJ 2:1 and 2:2 supplemented with 0.5 g enzymes mixture kg−1 diet with insignificant differences between group. The diet incorporating FM: CSJ 2:1 with 0.5 g enzymes mixture showed the maximum (P < 0.05) villi length/width, ASA, and MSR values. Fish fed a diet containing FM: CSJ 1:2, and supplemented with 0.5 g of an enzyme mixture kg−1 diet had the maximum Hb, Htc, RBCs and WBCs values (P < 0.05). The highest (P < 0.05) TP and GL value was estimated in diet containing FM: CSJ; 1:2 without the addition of enzymes mixture. while, the best (P < 0.05) value of ALT and AST were showed in diet containing FM: CSJ 2:1 without the addition of enzymes. The highest TAC, GSH and SOD values were recorded by fish fed diet containing FM: CSJ 1:2 or 2:2 with 0.5 g enzymes mixture kg−1 diet. Fish fed diets comprising various ratios of FM: CSJ with 0.5 g enzymes mixture kg−1 diet had the lowest (P < 0.05) MDA value. In conclusion, using mixture of enzymes (protease, pepsin, trypsin, xylanase and amylase) at 0.5 g kg−1 in combination with a high blend of CSJ instead of FM; 2:2 improved the growth performance, digestibility, digestive enzyme, intestinal morphology, blood indices, and immune response of Nile tilapia.

Triploidization modulates intestinal microbiota and promotes growth in Carassius auratus

Intestinal microbiota plays a key role in modulating host growth. However, the effect of triploidization on intestinal microflora and fast growth has not been fully explored. Here, autotriploid Carassius auratus (3nRR, 3n = 150) derived from Carassius auratus red var. (♀, RCC, 2n = 100) × autotetraploid fish (♂, 4nRR, 4n = 200) was established. Intestinal microbial community analysis of RCC and 3nRR was performed by 16S rRNA gene sequencing. Gut characteristics, growth rate, and digestive enzyme activity of the two groups of fish were explored. Significant changes in gut assemblages were observed in 3nRR fish. Differences in intestinal characteristics (structure, relative gut density, relative gut length, relative gut mass, and Zihler's index) were observed between RCC and 3nRR groups. Associations between microbial assemblages and intestinal characteristics were evaluated. Growth rate and activities of intestinal digestive enzymes (cellulase, amylase and trypsin) were higher in 3nRR compared with that in RCC. Spearman's correlation analysis showed a positive correlation between bacteria orders (Clostridiales, Micrococcales and Lactobacillales) and fast growth in 3nRR. In summary, the findings indicated that triploidization caused changes in gut microbiota and characteristics, and digestive enzyme activity. The relative abundance of several bacteria species was positively correlated with fast growth in 3nRR. The present study provided new insights into the growth mechanism of 3nRR and its interaction with intestinal microorganisms.

Will ocean acidification affect the digestive physiology and gut microbiota of whelk Brunneifusus ternatanus?

To understand the physiological responses of the Brunneifusus ternatanus to future ocean acidification (OA), histology, enzyme activity and gut bacterial composition at different pH levels (Control: C group, pH 8.1; Exposure period: EP group, pH 7.3) for 28 days were studied under laboratory conditions. Microbiota composition was analyzed using 16S rRNA gene amplicon sequencing. Enzyme activities of trypsin (TRY), lipase (LPS), amylase (AMS), and lysozyme (LZM) were used as biochemical indicators, as well as weight gain rate (WGR), specific growth rate (SGR) as growth indicators. The stress caused by OA resulted in alterations to the intestine, including partially swollen and degranulated enterocytes and rough endoplasmic reticulum (RER). The relative abundance of the core phylum in the acidified group changed significantly, showing an increase in Tenericutes and a decrease in Proteobacteria. Firmicutes/Bacteroides ratio declined from 4.38 in the control group to 1.25 in the EP group. We found that the enzymes TRY, LPS, and AMS activities were inhibited at reduced pH, which was positively correlated with the dominant genera Mycoplasma and Bacteroides; while LZM activities showed a significant increment, but showing a strong negative correlation. Furthermore, both WG and SRG values showed a depression at low pH lever. These results suggest that if anthropogenic CO2 emissions continue to accelerate, OA could negatively impact the whelk’s health, compromising their growth performance and even survival. These findings will benefit the future risk assessments of OA or other related emerging environmental issues.

Will ocean acidification affect the digestive physiology and gut microbiota of whelk Brunneifusus ternatanus?

To understand the physiological responses of the Brunneifusus ternatanus to future ocean acidification (OA), histology, enzyme activity and gut bacterial composition at different pH levels (Control : C group, pH 8.1; Exposure period : EP group, pH 7.3) for 28 days were studied under laboratory conditions. Microbiota composition was analyzed using 16S rRNA gene amplicon sequencing. Enzyme activities of trypsin (TRY), lipase (LPS), amylase (AMS), and lysozyme (LZM) were used as biochemical indicators, as well as weight gain rate (WGR), specific growth rate (SGR) as growth indicators. The stress caused by OA resulted in alterations to the intestine, including partially swollen and degranulated enterocytes and rough endoplasmic reticulum (RER). The relative abundance of the core phylum in the acidified group changed significantly, showing an increase in Tenericutes and a decrease in Proteobacteria. Firmicutes/Bacteroides ratio declined from 4.38 in the control group to 1.25 in the EP group. We found that the enzymes TRY, LPS, and AMS activities were inhibited at reduced pH, which was positively correlated with the dominant genera Mycoplasma and Bacteroides; while LZM activities showed a significant increment, but showing a strong negative correlation. Furthermore, both WG and SRG values showed a depression at low pH lever. These results suggest that if anthropogenic CO2 emissions continue to accelerate, OA could lead to a negative impact on the whelk health, also compromising their growth performance and even survival. These findings will benefit the future risk assessments of OA or other related emerging environmental issue.

Trypsin/α-Amylase Inhibitors from Capsicum chinense Seeds: Characterization and Antifungal Activity against Fungi of Agronomic Importance.

Protease inhibitors (PIs) have attracted attention due to their important roles in plant defense. The objective of this work was to characterize and evaluate the antimicrobial activity of the peptides of a family of serine PIs from Capsicum chinense Jacq. seeds. Initially, PIs were extracted from the seeds and subjected to purification by chromatography, resulting in three different peptide enriched fractions (PEFs) termed PEF1, PEF2 and PEF3. Subsequently, the PEF3 was subjected to trypsin inhibition assays, α-amylase activity assays, antimicrobial activity assays on phytopathogenic fungi, and assays to determine the likely mechanisms of action. The PEF3 was composed of three protein bands with molecular masses ranging between 6 and 14 kDa. The amino acid residues of the ~6 kDa band showed high similarity with serine PIs. PEF3 inhibited the activity of the enzymes trypsin, human salivary α-amylase, and Tenebrio molitor larval α-amylase and inhibited the growth of phytopathogenic fungi, showing 83.7% loss of viability in Fusarium oxysporum. PEF3 induced reactive oxygen species in Colletotrichum lindemuthianum and F. oxysporum to dissipate their mitochondrial membrane potential and activated caspases in C. lindemuthianum. Our results reinforce the importance of PIs in plant defense mechanisms against phytopathogenic fungi as well as in their biotechnological applications for the control of plant pathogens.

Anticancer Activity of Venom Protein Hydrolysis Fraction of Equatorial Spitting Cobra (&lt;i&gt;Naja sumatrana&lt;/i&gt;)

Bioactive peptides play an important role in targeting cancer cells. Venom protein from Naja sumatrana can be explored as a source of bioactive peptides. This research aims to identify and study the molecular docking of bioactive peptides (BPs) from trypsin hydrolysate of N. sumatrana venom protein which was fractionated using an SPE C18 column. The venom of N. sumatrana was hydrolyzed with trypsin enzyme. The protein hydrolysate was then fractionated using an RP-SPE HyperSep Retain PEP column, and the peptide fractions were tested for their anticancer activity against MCF-7 breast cancer cells using the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Identification of peptides in the active fraction was carried out through high-resolution mass spectrometry. The identified peptides were molecularly docked with the EGFR receptor using AutoDock Vina. The results showed that the degree of hydrolysis was 74.7%. The 75% methanol fraction is the active fraction against MCF-7 cells, with an IC50 value of 4.80 μg/mL and a selectivity index of 5.00. Peptide-active anticancer fractions with the sequence of NSLLVK, SSLLVK and TVPVKR were successfully identified and exhibited high binding affinity values, good RMSD values, and the most suitable model for the epidermal growth factor receptor.