Acid Protease Activity Research Articles

Effects of metamifop on ammonia production and metabolism of Monopterus albus

The use of herbicides is believed to have an impact on the metabolism, physiology and biochemistry of fish. In this study, we studied the effects of metamifop on the production and metabolism of Monopterus. albus living in the water. According to the semi-lethal concentration of metamifop for 96 h, four MET concentration groups (0.2-, 0.4-, 0.6- and 0.8 mg L−1) were set up for 96 h exposure test. The ammonia discharge rate decreased, hemolymph ammonia content increased significantly, and hemolymph urea nitrogen content decreased at all time periods of metamifop exposure. In liver, the protein content decreased, the neutral protease content increased significantly (p < 0.01), amino acid content increased, and ATP content increased significantly (p < 0.01). In brain, the protein content increased, the activity of acid protease, neutral protease and alkaline protease all decreased, amino acid content decreased significantly (p < 0.01), and the content of ATP decreased. Glutamic-pyruvic transaminase (GPT) activity did not change in liver but decreased in brain. Glutamine synthetase (GS) activity decreased in liver and increased in brain. Glutaminase (GLS) activity decreased in liver and increased in brain. In conclusion, the liver and brain tissues of M. albus react differently to MET exposure. The liver mainly synthesizes energy through hydrolyzed protein, while the brain mainly synthesizes protein. Amino acids produced by protein hydrolysis cannot be converted to alanine for storage, and the degraded amino acids lead to the elevation of endogenous ammonia. MET inhibits the removal of ammonia from M. albus. Only liver tissue can detoxify the eel by converting ammonia into glutamine. Brain should have to tolerate high levels of endogenous ammonia.

Transcriptomic profiling revealed important roles of amino acid metabolism in fruiting body formation at different ripening times in Hypsizygus marmoreus.

Hypsizygus marmoreus is an industrial mushroom that is widely cultivated in East Asia. Its long postripening stage before fruiting severely limits its industrialized production. Five different mycelial ripening times (30, 50, 70, 90, and 100 d) were chosen and primordia (30P, 50P, 70P, 90P, and 110P) were collected for comparative transcriptomic analyses. The corresponding substrates (30F, 50F, 70F, 90F, and 110F) were used for nutrient content and enzyme activity determination. In pairwise comparisons between 110P and other primordia, a total of 1,194, 977, 773, and 697 differentially expressed genes (DEGs) were identified in 30P_110P, 50P_110P, 70P_110P, and 90P_110P, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) functional enrichment analyses revealed that the DEGs were mainly associated with amino acid metabolism, and lipid and carbohydrate metabolism pathways. Tyrosine, tryptophan, phenylalanine and histidine metabolism were enriched in all groups. Among the main carbon nutrients, the contents of cellulose and hemicellulose were high, and the lignin content decreased with the extension of the ripening time. Laccase had the highest activity, and acid protease activity decreased with the extension of the ripening time. The highly enrichment for amino acid metabolic pathways in primordia reveals that these pathways are essential for fruiting body formation in H. marmoreus, and these results will provide a basis for the optimization of its cultivation.

Accelerated Accumulation of γ-Aminobutyric Acid and Modifications on Its Metabolic Pathways in Black Rice Grains by Germination under Cold Stress

Germination can increase γ-aminobutyric acid (GABA) accumulation in grains, but the combined effects of germination and other external stress on rice grains have been little studied. In this investigation, enhanced accumulation of GABA and modification of its metabolic pathways in black rice grains were investigated during germination under cold stress. The combination of cold stress and germination resulted in a greater accumulation of GABA than germination alone. The treatment of cold stress at 0 °C for 1 h and germination for 72 h induced a maximum GABA content of 195.64 mg/100 g, 51.54% higher compared to the control, which was superior to any other treatment. We modified the metabolism of the GABA shunt to the orientation of GABA synthesis, in which the activity of glutamic acid decarboxylase and protease were stimulated. The total content of free amino acid indicated an upward trend as germination prolonged. The degradation of polyamines was partly promoted due to elevated diamine oxidase and polyamine oxidase activity, but the activity of amino-aldehyde dehydrogenase for the direct synthesis of GABA in the pathway was suppressed. The result implied that the GABA shunt might play a major role in enhancing GABA accumulation induced by cold stress and germination rather than the polyamines degradation pathway. This investigation provides a practical reference for GABA accumulation by germination under cold stress and a theoretical basis for the possible mechanism underlying the accelerating action.

Assessing the Fate of Superparamagnetic Iron Oxide Nanoparticles Carrying Usnic Acid as Chemical Cargo on the Soil Microbial Community.

In the present study we evaluate the effect of superparamagnetic iron oxide nanoparticles (SPIONs) carrying usnic acid (UA) as chemical cargo on the soil microbial community in a dystrophic red latosol (oxysol). Herein, 500 ppm UA or SPIONs-framework carrying UA were diluted in sterile ultrapure deionized water and applied by hand sprayer on the top of the soil. The experiment was conducted in a growth chamber at 25 °C, with a relative humidity of 80% and a 16 h/8 h light-dark cycle (600 lx light intensity) for 30 days. Sterile ultrapure deionized water was used as the negative control; uncapped and oleic acid (OA) capped SPIONs were also tested to assess their potential effects. Magnetic nanostructures were synthesized by a coprecipitation method and characterized by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), zeta potential, hydrodynamic diameter, magnetic measurements, and release kinetics of chemical cargo. Uncapped and OA-capped SPIONs did not significantly affect soil microbial community. Our results showed an impairment in the soil microbial community exposed to free UA, leading to a general decrease in negative effects on soil-based parameters when bioactive was loaded into the nanoscale magnetic carrier. Besides, compared to control, the free UA caused a significant decrease in microbial biomass C (39%), on the activity of acid protease (59%), and acid phosphatase (23%) enzymes, respectively. Free UA also reduced eukaryotic 18S rRNA gene abundance, suggesting a major impact on fungi. Our findings indicate that SPIONs as bioherbicide nanocarriers can reduce the negative impacts on soil. Therefore, nanoenabled biocides may improve agricultural productivity, which is important for food security due to the need of increasing food production.

Microbial driving mechanism of soil conditioner on reducing cadmium uptake by rice and improving soil environment

Soil conditioners can reduce the transfer of heavy metal ions from the soil to crops and play a crucial role in safe food production. However, it remains unclear how soil conditioners reduce cadmium (Cd) accumulation in rice (Oryza sativa L.). In this study, five soil conditioners (U-, N-, T-, L-, and C-type) commonly used in China were selected, and the effects of soil conditioners on bacterial and fungal community diversity, soil enzyme activity, soil pH, and organic matter content were investigated through field experiments in two sites. The Cd content of rice was significantly reduced by 32.4–55.1 % in site I and 16.0–33.3 % in site II under the five soil conditioner treatments. The decrease in Cd content was related to the increase in soil pH, organic matter content, and Cd fixation-related flora caused by soil conditioner application. U-, N- and C-type conditioners increased soil pH, inducing an increase in the relative abundances of microbial populations related to Cd sorption and sequestration (Firmicutes, Nitrospirota, Actinobacteriota, and Methylomirabilota). U-, T-, and L-type conditioners increased soil organic matter, causing an increase in the relative abundance of microbial flora associated with macromolecule degradation, including bacteria (Acidobacteriota and Chloroflexi) and fungi (Ascomycota and Basidiomycota). Conditioner application reduced the availability of soil Cd; indirectly promoted the increased abundance of beneficial soil bacteria; and increased the activities of invertase, urease, dehydrogenase, catalase, and acid protease. In conclusion, soil conditioner reduces the effective soil Cd by adjusting soil pH and organic matter content, increasing Cd-passivating flora and Cd-tolerant flora. Soil conditioner also increases the abundance of other beneficial flora, enhances soil enzyme activity, promotes the microecological balance of soil under Cd stress, and finally reduces Cd accumulation in rice.

Ontogeny of digestive enzymes in clown anemonefish larvae, Amphiprion ocellaris (Perciformes: Pomacentridae)

Introduction: Clown anemonefish (Amphiprion ocellaris) is the most popular fish species in the marine aquarium trade, however, there is a lack of information on their digestive physiology during larvae ontogeny, valuable information that helps in the design of specific diets, as well as management protocols for the species. Objective: Characterize the early development of digestive enzymes of A. ocellaris during larvae ontogeny. Methods: From hatching until the 38th day after hatching (DAH), the specific activity of acid and alkaline proteases, trypsin, chymotrypsin, leucine aminopeptidase and lipase were analyzed, while acid and alkaline proteases zymograms were performed. Results: At hatching, all measured enzymes activities were detected. Acid proteases increased in activity from hatching until the 38th DAH. Alkaline proteases, trypsin, chymotrypsin, and leucine aminopeptidase showed the same pattern and maximum activity on the 8th DAH, decreasing at the 38th DAH. Lipase activity showed peaks on the 8th and 30th DAH. Acid zymogram showed a single band, appearing on the 8th DAH. A total of eight alkaline proteases were revealed (154.2, 128.1, 104.0, 59.8, 53.5, 41.9, 36.5 and 25.1 KDa), showing seven bands on the 1st DAH and all bands from the 3rd to 8th DAH, decreasing at two bands (41.9 and 25.1 KDa) in the 38th DAH. Conclusion: A. ocellaris shows a functional stomach on the 8th DAH, where the species on the 38th DAH shows digestive enzymatic pattern to omnivore with a tendency to carnivory. Objective: Characterize the early development of digesive enzymes of A. ocellaris during larval ontogeny. Methods: From hatching until the 38th days after hatching (DAH), the specific activity of acid and alkaline proteases, trypsin, chymotrypsin, leucine aminopeptidase and lipase were analysed, while acid and alkaline proteases zymograms were perfomed. Results: At hatching, all measured enzymes activities were detected. Acid proteases increased in activity from hatching until the 38th DAH. Alkaline proteases, trypsin, chymotrypsin and leucine aminopeptidase showed same pattern and maximum activity on the 8th DAH, decreasing at the 38th DAH. Lipase showed activity peaks on the 8th and 30th DAH. Acid zymogram showed a single band, appearing on the 8th DAH. Total of eight alkaline proteases were reveled (154.2, 128.1, 104.0, 59.8, 53.5, 41.9, 36.5 and 25.1 KDa), showing seven bands on the 1st DAH and all band from the 3rd to 8th DAH, decreasing at two bands (41.9 and 25.1 KDa) in the 38th DAH. Conclusion: Therefore, A. ocellaris shows functional stomach on the 8th DAH, where the species on the 38th DAH shows digestive enzymatic pattern to omnivore with a tendency to carnivory.

Effects of sowing methods on nitrogen compounds and protease activities of whole‐crop wheat silage

AbstractBackgroundWhole‐crop wheat (Triticum aestivum) has high nutritive value, and it has become one of the main sources of roughage for ruminants in some countries or regions. This study investigates the effects of no tillage on nitrogen compounds and protease activities of whole‐crop wheat silage.MethodsWheat was planted on the 9th day (NB9) and 5th day (NB5) before rice harvest and on the first day after rice harvest. Sowing before harvest involved no tillage and sowing after rice harvest involved either no tillage (NA1) or conventional tillage (CK).ResultsCompared to CK, the crude protein content of NB9 and NB5 decreased by 16.4% and 9.58%, respectively. With the delay of the sowing date, the contents of non‐protein nitrogen, rapidly degraded protein, and slowly degraded protein in whole‐plant wheat tended to increase. Compared to NA1 wheat silage, the NH3‐N content of NB9 and NB5 silages decreased by 52.7% and 34.4%, respectively. The acid protease activity of NA1 was significantly higher than that of other treatments (p &lt; 0.05).ConclusionsThere was no significant difference in the degree of protein degradation between NA1 and CK silages. Although the degree of protein degradation in early sowing was low, the degree of fermentation was also weak.

The differences in main components, enzyme activity, and microbial composition between substandard and normaljiuyao.

Jiuyao is a critical fermenting agent in traditional huangjiu brewing and it affects the quality of huangjiu. To assess and monitor the quality of jiuyao effectively we determined the differences between two common types of substandard jiuyao and normal jiuyao, with emphasis on the comparison of the main components, enzymatic activity, volatile substances, and microbial community structure. The water and starch content, acid protease activity, and esterification capability of type I substandard jiuyao were significantly lower than those of the normal jiuyao, and the protein contents, liquefaction capability, glycation capability, and neutral protease activity were substantially higher than those of the normal jiuyao. Type II substandard jiuyao had significantly lower indices than the normal group except for the starch and free amino acid content, which were significantly higher than those of the normal jiuyao. Significant differences were observed between substandard and normal jiuyao in the content of 21 volatile compounds. 2-Pentylfuran could be used as a marker of substandard jiuyao. Type I substandard jiuyao contained a higher abundance of aerobic Pediococcus and Marivita in comparison with the normal jiuyao. Type II substandard jiuyao consisted of a greater abundance of anaerobic Mucor and Staphylococcus. The quality of jiuyao was significantly affected by the water content. Due to the different abundances of aerobic and anaerobic bacteria in jiuyao, oxygen may also be an important parameter affecting the quality of jiuyao. We believe that the present study offers a theoretical basis for the evaluation and control of the quality of jiuyao. © 2023 Society of Chemical Industry.

Low temperature decreased insecticidal protein contents of cotton and its physiological mechanism.

Low temperature delayed cotton growth, increased abscission of reproductive organs, and seriously reduced quality and yield. Moreover, failed or unstable performance of insecticidal resistance due to adverse environments have been reported. In order to study the impact of low temperature on the insecticidal protein contents at square stage in Bacillus Thuringenesis (Bt) transgenic cotton, different temperature regimes and durations were imposed on two Bt cotton cultivars, Sikang1 (the conventional cultivar, SK1) and Sikang3 (the hybrid cultivar, SK3). Low temperature stress exhibited a significant inhibitory effect on insecticidal protein expression in squares and leaves of Bt transgenic cotton plants, with insecticidal protein contents decreased up to 30% with decreasing temperature. In addition, the threshold temperature resulting in significant reduction of insecticidal protein contents symbolized a rising trend as stress duration extended, together with a greater reduction observed. Thus, at square stage, the detrimental influence of low temperature on Bt protein contents was closely related to the low temperature level and duration. The square Bt protein content was positively correlated with leaf Bt protein content, but was more sensitive to low temperature. Across the whole treatment duration in both years, square Bt protein level was significantly negatively correlated with malondialdehyde (MDA) contents, as well as the activities of catalase (CAT) and superoxide dismutase (SOD), indicating the negative effect of cold induced oxidative stress on Bt protein contents. The reduced Bt protein contents under low temperature were also related to altered N metabolism. Glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities, as well as soluble protein contents in squares reduced, and greater reduction was recorded with decreasing temperature. In contrast, the free amino acid contents, and peptidase and protease activities increased, and greater elevation was noted with decreasing temperature. These results suggested in Bt cotton production, it is necessary to be alert to low temperature disasters that may last for more than 24 hours and lower than 15-17°C during the square stage, which may lead to reduced insecticidal resistance causing serious economic losses.

Bran from composite grain mixture as an object of deep processing. Part 1. Protein-proteinase complex

Deep processing of grain bran is an important, promising direction that allows the use of by-products (secondary products) of flour milling in order to obtain valuable food components for the creation of enriched food products, as well as specialized grain-based products. Polycomponent bran, obtained during the joint processing of cereals (wheat), legumes (lentils) and oilseeds (flax), in terms of its chemical composition and the state of the proteinproteinase complex, is a unique raw material that can be used for further processing. In particular, it is suitable for the use in producing hydrolysates and other structurally modified products using enzymatic biocatalytic methods. An assessment of the chemical composition and biochemical characteristics of new types of bran showed a high protein content, in which the proportion of the albumin-globulin fraction predominated (78.5-86%), while a significant part of the protein (7.6-10%) was strongly bonded to other biopolymers. The bran proteolytic enzymes acting in the neutral (pH 6.8) and acidic (pH 3.8) pH zones were isolated and studied. It was shown that lentil-flax bran was characterized by the highest proteolytic activity, while the activity of neutral proteinases exceeded the activity of acid proteinases in all three variants: 1.32, 1.37 and 1.56 times, respectively. It was established that protein inhibitors of trypsin and their own proteinases were present in all studied bran types. They inhibited the activity of acid proteinases to a greater extent than neutral ones (% inhibition): 37.5 versus 28.2 (option 1); 32.3 versus 24.5 (option 2); 48.6 versus 32.4 (option 3). The molecular weight, according to gel chromatography, was as follows: neutral proteinases 250,000 200,000 Da, acid proteinases 100,000 75,000 Da. Protein inhibitors isolated from multicomponent bran had a molecular weight of 25,000-20,000 Da. The data obtained will be used in experimental studies on targeted biocatalysis in order to obtain products of a given composition and properties.

Substituting fish meal with a bacteria protein (Methylococcus capsulatus, Bath) grown on natural gas: Effects on growth non-specific immunity and gut health of spotted seabass (Lateolabrax maculatus)

This study aimed to evaluate effects of substituting fish meal (FM) by methanotroph (Methylococcus capsulatus, Bath) bacteria meal (FeedKind®, FK) on growth performance, non-specific immunity and gut health of Lateolabrax maculatus. Six iso-nitrogenous diets were formulated with 0, 3.5%, 7%, 10.5%, 14% and 17.5% FK to substitute 0 (control group, FM content: 35%), 10%, 20%, 30%, 40% and 50% fish meal, referred to as FM, FK3.5, FK7, FK10.5, FK14, and FK17.5 respectively. Fish (initial body weight: 11.00 ± 0.02 g) were fed experimental diets for 56 days. Results showed that growth of fish fed the FK3.5 diets was significantly increased (P < 0.05) but that there was no significant difference (P > 0.05) in growth of the other groups (FK7-FK17.5) compared with control group. Although survival of fish in the 50% substitution group was significantly decreased (P < 0.05) compared with the other groups, there was no overall trend in the survival data. The activities of serum acid phosphatase (ACP), alkaline phosphatase (AKP), gut lipase and protease and the contents of serum total protein and albumin in the FK3.5 group were significantly higher than those of control group (P < 0.05). In contrast, the activities/contents of serum ACP, AKP, lysozyme and complement 4 in the FK10.5, FK14 and FK17.5 groups were significantly decreased compared with control group. There was no significant difference in gut mucosal structure among all groups. The analysis of gut flora showed that the relative abundance of Lactobacillus in the FK7 and FK10.5 groups was significantly higher than other groups. In conclusion, dietary FK inclusion level up to 14% of total diet to replace 40% FM is possible without negatively affecting the growth performance of spotted seabass. Furthermore, the replacement of FM with 3.5% FK enhances the growth and immune, and substituting 20–30% of FM by 7–10.5% FK increased the abundance of beneficial bacteria in intestine of fish.

Characteristics of nitrogen distribution and its response to microecosystem changes in green infrastructure with different woody plants

With the acceleration of urbanization, N pollution in rainfall runoff has become the primary cause of eutrophication. In order to control N pollution in rainfall runoff, green infrastructure (GI) has been widely implemented. However, little is known about the process through which plants, especially woody plants, affect N distribution and the microecosystem in GI. Limited information suggests that woody plants mainly affect N distribution and alter the microecosystem through the influence of their roots. Therefore, laboratory tests were conducted to investigate the roles of the taproot plant Sophora japonica and the fibrous root plant Malus baccata and the resultant changes at the microecosystem level regarding N removal in a column-scale GI. After one year of growth, analysis of the morphological traits of the roots revealed that the average root length and diameter of S. japonica were approximately 2.3 and 1.8 times greater than those of M. baccata, respectively. An investigation of microbial diversity revealed that in comparison to the control GI system without plants, the GI systems with S. japonica and M. baccata hosted 45.68% and 59.88% more Actinobacteria, respectively. Further, the soil urease (S-UE) activities in the GI systems with S. japonica and M. baccata were 13.6% and 98.8% higher than that in the control, respectively, and the soil acid protease (S-ALPT) activities were 20.5% and 25.4% higher than that in the control, respectively. Compared to the control and the S. japonica GI system, the NH3–N content in the soil of the M. baccata GI was 94.4% and 15.2% lower, respectively, and the NO3–N content was 57.3% and 12.7% lower, respectively. The M. baccata GI system had the lowest NH3–N and NO3–N contents because it was most abundant in Actinobacteria and Arthrobacter and had the highest S-UE and S-ALPT activities. The results may be useful for improving N removal in GI containing different woody plants, and by extension for improving control of N pollution from rainfall runoff.

Microbial Community, Co-Occurrence Network Relationship and Fermentation Lignocellulose Characteristics of Broussonetia papyrifera Ensiled with Wheat Bran.

Broussonetia papyrifera has a high lignocellulose content leading to poor palatability and low digestion rate of ruminants. Thus, dynamic profiles of fermentation lignocellulose characteristics, microbial community structure, potential function, and interspecific relationships of B. papyrifera mixing with wheat bran in different ratios: 100:0 (BP100), 90:10 (BP90), 80:20 (BP80), and 65:35 (BP65) were investigated on ensiling days 5, 15, 30, and 50. The results showed that adding bran increased the degradation rate of hemicellulose, neutral detergent fiber, and the activities of filter paper cellulase, endoglucanase, acid protease, and neutral protease, especially in the ratio of 65:35. Lactobacillus, Pediococcus, and Weissella genus bacteria were the dominant genera in silage fermentation, and Pediococcus and Weissella genus bacteria regulated the process of silage fermentation. Compared with monospecific B. papyrifera silage, adding bran significantly increased the abundance of Weissella sp., and improved bacterial fermentation potential in BP65 (p < 0.05). Distance-based redundancy analysis showed that lactic acid bacteria (LAB) were significantly positive correlated with most lignocellulose content and degrading enzymes activities, while Monascus sp. and Syncephalastrum sp. were opposite (p < 0.05). Co-occurrence network analysis indicated that there were significant differences in microbial networks among different mixing ratios of B. papyrifera silage prepared with bran. There was a more complex, highly diverse and less competitive co-occurrence network in BP65, which was helpful to silage fermentation. In conclusion, B. papyrifera ensiled with bran improved the microbial community structure and the interspecific relationship and reduced the content of lignocellulose.

Characterizing the gastrointestinal development and digestive enzyme ontogeny of larval Amphiprion ocellaris

Clownfish (Amphiprion ocellaris) are the most recognizable and popular marine aquarium fish and are a key commodity for marine ornamental fish producers. Although these fish have been raised in captivity for decades, producers are still experiencing issues regarding larval survival, reliance on live feeds, and post-larval deformities. To improve the culture process, the ontogeny of larval development and digestive capacity should be elucidated. The morphological development, digestive enzyme ontogeny, and digestive tract development of A. ocellaris was examined in a 16-day trial. Standard microplate assays were conducted to quantify the activity of trypsin, lipase, and acid protease enzymes from 24 h before hatching to 15 days post hatch (DPH). Histology was used to visualize morphological changes in the digestive tract throughout the larval period. At hatching, A. ocellaris has functional eyes, an open mouth, and a coiled, differentiated digestive tract. Trypsin and lipase activities were detectable before hatching and increased significantly later in the larval period. Gastric gland formation was observed at 6 DPH, with stomach functionality occurring between 7 and 9 DPH, indicated by gastric gland proliferation and an increase in acid protease activity. The results from this study may be used to inform weaning protocols to maximize larval growth and survival while minimizing the use of costly live feeds.

Poly‐β‐hydroxybutyrate concentration, microbial enzymes activity, and nutritional value in biofloc system using different carbon sources and C/N ratios in common carp, Cyprinus carpio culture

AbstractThis experiment was designed with three carbon sources (Dextrin, wheat bran, and corn starch), each with two carbon to nitrogen (C/N) ratios (19 and 30) for 4 weeks. The data obtained from two variables (carbon sources, C/N ratio) were analyzed with a two‐way analysis of variance. At the end of the experiment, the results indicated that the use of varying carbon sources and C/N ratios significantly changed the nutritional value of microbial flocs (p &lt; 0.05). Also, the results showed that both variables significantly affected the main groups of saturated, mono‐unsaturated, and polyunsaturated fatty acids in the microbial flocs (p &lt; 0.05). Dextrin flowing corn starch at a low C/N ratio significantly increased poly‐β‐hydroxybutyrate accumulation in microbial flocs (p &gt; 0.05). The microbial enzyme profile changed in all carbon sources but C/N ratios did not affect microbial enzymes in the treatments except in a significantly higher value for amylase and acidic protease activity at a C/N ratio of 30 (p &lt; 0.05). Also, at the end of the experiment, total bacteria and Lactobacillus count were affected by carbon sources and the highest density was observed in wheat bran and Dextrin respectively. These findings may encourage farmers to consider specific carbon sources and C/N ratios based on culture conditions and species requirements.

CBD Supplementation Has a Positive Effect on the Activity of the Proteolytic System and Biochemical Markers of Honey Bees (Apis mellifera) in the Apiary.

Simple SummaryThe purpose of our study was to determine how CBD extract influences resistance in the hemolymph (insect blood) of honey bees in the hive test. The bees were divided into 3 groups: (CSy) bees fed with CBD in sugar syrup; (CSt) cotton strip with CBD placed in hive, (C) control bees fed sugar syrup. To determine the state of immunity, we used the analysis of the activity of the proteolytic system and biochemical markers, such as “liver tests”, and the concentration of selected ions and key compounds for the functioning of the organism. CBD extract increased the total protein concentration, proteases and their inhibitor activities in each age (except for acidic protease activities in the 21st and 28th day and alkaline protease inhibitor activities in the 28th day in the CSt group), increased concentrations of markers: ALP, AST, ALT; and glucose; triglycerides; cholesterol and creatinine. A decrease in concentration in experimental groups was noticed for urea acid and albumin compared to group C. Higher activities/concentrations of most of parameters were obtained in the CSy compared to the CSt and C. The CBD supplementation can positively influence bees’ resistance.We examined how CBD extract influences the activity of the immune system in the hemolymph of honey bees in the hive test. The bees were divided into 3 groups: (CSy) bees fed with CBD in sugar syrup with glycerin; (CSt) cotton strip with CBD placed in hive bees fed pure sugar syrup, (C) control bees fed sugar syrup with glycerin. CBD extract increased the total protein concentrations, proteases and their inhibitor activities in each age (the except for acidic protease activities in the 21st and 28th day and alkaline protease inhibitor activities in the 28th day in CSt group) in comparison with group C. In the groups with the extract there was also an increase in the enzymatic marker activities: ALP, AST (decrease on day 28 for CSt), ALT; and non-enzymatic marker concentrations: glucose; triglycerides; cholesterol and creatinine. The urea acid and albumin concentrations were lower in CSy and CSt groups compared to the C group (higher concentration of albumin was displayed by control bees). Higher activities/concentrations of most of biochemical parameters were obtained in the CSy compared to the CSt and C. CBD supplementation can positively influence workers’ immune system.

Influence of the biofloc bacterial community on the digestive activity of Nile tilapia (Oreochromis niloticus)

High-throughput sequencing was performed to study the diversity of bacterial communities in the water of an aquaculture production system using Biofloc technology (BFT) and its effect on the activity of digestive enzymes in Nile tilapia, Oreochromis niloticus. Sex-reversed juveniles were reared in six circular indoor tanks (1 m3) for 12 weeks. The following treatments were performed: biofloc with 0% protein restriction in the diet (BFTH = high protein diet); biofloc with 11% dietary protein restriction (BFTL = low protein diet), and clear water control with 0% dietary protein restriction (CW). Biofloc groups showed a higher bacterial diversity and a completely different composition compared to CW, with significant increase of Actinobacteria and Planctomycetes and a decrease in Verrumicrobia and Fusobacteria. At the genus level, Flavobacterium, Thermomonas, Comamonas, Microbacterium, and Intestinibacter present in BFT significantly correlated with the activity of trypsin, aminopeptidase, and alkaline proteases. Twenty percent of the difference between the biofloc groups was due to the higher activity of acid proteases and aminopeptidases. The metagenome prediction revealed metabolic pathways differentially expressed in BFTH and BFTL. Most were similarly expressed in both treatments; except for the CoA degradation pathway I, which was expressed in BFTL, and the biosynthesis of isoprene II and mevalonate II in BFTH. The biofloc microbiota provided enzymes that, in synergy with the endogenous digestive enzymes of the fish, improved digestion and nutrient assimilation. The study provides knowledge on the exogenous enzymatic contribution and diversity of the bacterial groups present in the biofloc; the contribution of these microorganisms in digestive metabolism and fish performance is also highlighted.

Soil quality and r – K fungal communities in plantations after conversion from subtropical forest

Intensive clear-cutting of natural forests and conversion to monoculture plantations are ongoing worldwide, leading to the degradation of soil quality and microbial functions. Here, we compared soil quality index (SQI) and fungal communities in a natural forest (Forest) and four 5-year-old monoculture plantations, including Camellia oleifera (Oil), Amygdalus persica (Peach), Myrica rubra (Berry) and Cunninghamia lanceolate (Fir) in a subtropical region of China. After conversion, soil pH in the plantations rose up to 0.31, but organic carbon and total nitrogen contents, sucrase, acid protease, glutaminase, acid and alkaline phosphatase activities decreased by 83%, 59%, 40%, 64%, 66%, 94% and 59%, respectively. Correspondingly, the SQI dropped by 65%. High-throughput sequencing of the ITS1 region demonstrated an increase in α-diversity and a striking difference in β-diversity of fungi following conversion. Changes in the dominant fungal taxa following forest conversion to plantations were interpreted by r- and K-selection of life strategies. Conversion increased the fungal groups with r-strategies, such as Ascomycota and Zygomycota, but decreased the fungal groups with K-strategies, such as Basidiomycota. Genera affiliated to those phyla including Pseudophialophora, Rhytisma increased, but Russula decreased. Redundancy analysis and structural equation modeling indicated that the diversity and composition of fungal communities changed with soil degradation, which was mainly driven by increased pH and total phosphorus content, but decreased C/N ratio and C and N related enzymes activities. Overall, the conversion of forest to monoculture plantations decreased soil quality and the abundance of K-strategists, retarded the decomposition of persistent organic matter, but boosted the prevalence of r-strategists in a more diverse fungal community.

Enzyme activity of Aspergillus section Nigri strains isolated from the Korean fermentation starter, nuruk.

Aspergillus section Nigri is a fungus used industrially because of its ability to produce enzymes such as cellulolytic, amylolytic and proteolytic enzymes. In this study, we obtained twenty-eight strains of Aspergillus section Nigri from the traditional Korean fermentation starter, nuruk, which is known as a mixed culture of enzymatic filamentous fungi and yeasts. All strains were identified as Aspergillus section Nigri through combined phylogenetic analysis using partial β-tubulin and calmodulin gene sequences. The cellulase, amylase and protease activities of Korean strains were measured and compared with ten reference strains of Aspergillus niger. Most Korean strains showed higher cellulolytic activity than reference strains, and Aspergillus neoniger KCN5 showed the highest β-glucosidase activity. Two-thirds of the Korean strains showed similar levels of α- and glucoamylase activity as the reference strains. The protease activity of Aspergillus section Nigri strains was the highest at pH 3.0, and A. niger KSJ2 showed the highest acidic protease activity. By comparing ten reference strains and twenty-eight Korean strains, our results suggested useful Aspergillus section Nigri strains from nuruk with high enzyme activity, such as KCN5 and KSJ2, and their potential for industrial applications as enzyme producers.

Effects of intrinsic tannins on proteolysis dynamics, protease activity, and metabolome during sainfoin ensiling.

Condensed tannins (CT) from sainfoin have a high capacity to inhibit proteolysis. A previous study reported that CT from sainfoin can inhibit lactic acid bacteria activity and decrease ammonium-nitrogen (N) content during sainfoin ensiling; however, no study has focused on the metabolome of ensiled sainfoin. The objective of the present study was to investigate the effects of CT [following supplementation of deactivated CT with polyethylene glycol (PEG)] on protease activity, keystone bacteria, and metabolome during sainfoin ensiling. According to the results, PEG amendment increased non-protein N, amino acid, and soluble protein contents significantly (in the 49.08–59.41, 116.01–64.22, and 23.5–41.94% ranges, respectively, p < 0.05) during ensiling, whereas neutral detergent-insoluble protein and acid detergent-insoluble protein were decreased significantly (in the 55.98–64.71 and 36.58–57.55% ranges, respectively, p < 0.05). PEG supplementation increased aminopeptidase and acid protease activity after 3 days of ensiling (p < 0.05) and increased carboxypeptidase activity during the entire ensiling process (p < 0.05). The keystone bacteria changed following PEG addition (Stenotrophomonas, Pantoea, and Cellulosimicrobium in the control vs. Microbacterium, Enterococcus, and Brevundimonas in the PEG-treated group). In total, 510 metabolites were identified after 60 days of sainfoin ensiling, with 33 metabolites annotated in the Kyoto Encyclopedia of Genes and Genomes database. Among the metabolites, phospholipids were the most abundant (72.7% of 33 metabolites). In addition, 10 upregulated and 23 downregulated metabolites were identified in the PEG-treated group when compared with the control group, after 60 days of ensiling (p < 0.05). Pediococcus (correlated with 20 metabolites, R2 > 0.88, p < 0.05) and Lactobacillus (correlated with 16 metabolites, R2 > 0.88, p < 0.05) were the bacteria most correlated with metabolites. The results suggested antagonistic effects between Lactobacillus and Pediococcus during ensiling. The decreased proteolysis during sainfoin ensiling was mainly attributed to the inhibition of protease activity by CT, particularly carboxypeptidase activity. In addition, proteolysis decreased partly due to CT inhibiting Pediococcus activity during ensiling, with Pediococcus being significantly and positively correlated with dopamine after 60 days of ensiling (R2 = 0.8857, p < 0.05).