Immobilization of microbial multienzyme preparation on calcium alginate beads as well as lyophilization with mosambi peel matrix improved its shelf-life and stability

The purpose of the current study was to evaluate the functional activity and storage viability (at 4 °C and 35 °C) of an immobilized as well as lyophilized multienzyme, viz., pectinase, cellulase, and amylase (PCA) that was produced by Bacillus subtilis NG105 under solid state fermentation (SSF) at 35 ℃ for 10 days using mosambi peel as a substrate. After SSF, the culture media was divided into two aliquots. From the first aliquot, the produced ME was extracted, precipitated, and further immobilized on calcium alginate beads (MEICA). In order to immobilize on mosambi peel matrix, the second aliquot was mixed with acetone and subsequently lyophilized (MELMP). Thus, ready MEICA and MELMP extracted 87.5 and 91.5% juice from mango pulp, respectively. In the reusability study, after 5 cycles, MEICA exhibited 23.8%, 24.4%, and 36.5% PCA activity, respectively. The PCA activity of MEICA and MELMP was examined after 60 days of storage at 4 ℃. The result revealed that the PCA for MEICA declined from 100 to 66%, 58.2%, and 64.5%, respectively, while for MELMP, it dropped from 100 to 84.2%, 82.1%, and 69.7%, respectively. Further, after 60 days of storage, the reduction of total protein content (TPC) in free multienzyme (FME), MEICA, and MELMP was 92.2%, 91.5%, and 36.3% observed, respectively. In the localization study, the maximum levels of multienzyme activity were found in cell exudates. This study demonstrated that immobilizing of multienzyme through lyophilization on waste substrates like mosambi peel boosted its stability and shelf-life along with greatly reducing the cost of products.

The role of the Flb protein family in the life cycle of Aspergillus niger

Genes flbA-E are involved in sporulation and vegetative growth in Aspergillus nidulans. Inactivation of either of these genes results in a fluffy phenotype with delayed or even abolished sporulation. Previously, a non-sporulating phenotype was obtained by inactivating flbA in Aspergillus niger, which was accompanied by lysis, thinner cell walls, and an increased secretome complexity. Here, we further studied the role of the flb genes of A. niger. Strains ΔflbA, ΔflbB and ΔflbE showed increased biomass formation, while inactivation of flbA-D reduced, or even abolished, formation of conidia. Strain ΔflbA was more sensitive to H2O2, DTT, and the cell wall integrity stress compounds SDS and Congo Red (CR). Also, ΔflbC was more sensitive to SDS, while ΔflbB, ΔflbD, and ΔflbE were more sensitive to CR. On the other hand, inactivation of flbE increased resistance to H2O2. Enzyme secretion was impacted when the Δflb strains were grown on xylose. Strain ΔflbE showed reduced xylanase, cellulase and amylase secretion. On the other hand, amylase secretion at the periphery of the ΔflbA colony was reduced but not in its center, while secretion of this enzyme was increased in the center of the ΔflbB colony but not at its periphery. Inactivation of flbC and flbD also impacted zonal cellulase and amylase activity. Together, the Flb protein family of A. niger function in biomass formation, sporulation, stress response, and protein secretion.

Linkage-Editing Pseudo-Glycans: A Reductive α-Fluorovinyl-C-Glycosylation Strategy to Create Glycan Analogs with Altered Biological Activities

The acetal (O-glycoside) bonds of glycans and glycoconjugates are chemically and biologically vulnerable, and therefore C-glycosides are of interest as more stable analogs. We hypothesized that, if the O-glycoside linkage plays a vital role in glycan function, the biological activities of C-glycoside analogs would vary depending on their substituents. Based on this idea, we adopted a "linkage-editing strategy" for the creation of glycan analogs (pseudo-glycans). We designed three types of pseudo-glycans with CH2 and CHF linkages, which resemble the O-glycoside linkage in terms of bond lengths, angles, and bulkiness, and synthesized them efficiently by means of fluorovinyl C-glycosylation and selective hydrogenation reactions. Application of this strategy to isomaltose (IM), an inducer of amylase expression, and α-GalCer, which activates iNKT cells, resulted in the discovery of CH2-IM, which shows increased amylase production ability, and CHF-α-GalCer, which shows activity opposite that of native α-GalCer, serving as an antagonist of iNKT cells.

From static to semi-dynamic in vitro digestion conditions relevant for the older population: starch and protein digestion of cooked lentils

In the context of adequately feeding the rising older population, lentils have an important potential as sources of (plant-based) protein as well as slowly digestible bio-encapsulated starch and fibre. This study evaluated in vitro digestion of protein and starch in lentils under conditions representing the gastrointestinal tract of older adults. Both static and semi-dynamic simulations were applied to analyze the effect of specific gastrointestinal conditions (healthy versus older adult) on macronutrient digestion patterns. Gastric proteolysis was strongly dependent on applied gastric pH (gradient), leading to a lower extent of protein hydrolysis for simulations relevant for older adults. Fewer and smaller (lower degree of polymerization, DP) bioaccessible peptides were formed during gastric proteolysis under older adult compared to healthy adult conditions. These differences, developed during the in vitro gastric phase, were compensated during small intestinal digestion, yielding similar final proteolysis levels regardless of the applied simulation conditions. In contrast, in the presence of saliva, amylolysis was generally accelerated under older adult conditions. Moreover, the current work highlighted the importance of considering saliva (or salivary amylase) incorporation in simulations where the applied gastric pH (gradient) allows salivary amylase activity. Under both healthy and older adult conditions, in vitro starch hydrolysis bio-encapsulated in cotyledon cells of cooked lentils was attenuated, compared to a white bread reference.

High level food-grade expression of maltogenic amylase in Bacillus subtilis through dal gene auxotrophic selection marker

As a food-safe microorganism, Bacillus subtilis has been widely utilized in the production of food enzyme, where a food-grade expression system without antibiotic is required. However, there is no mature system for such expression, since the recombinant plasmid in existing food-grade expression system is unstable especially in high-density fermentation. In this study, we constructed a food-grade expression system based on the dal gene auxotrophic selection marker. Specifically, maltogenic amylase (AmyM) was expressed in dal deletion strain without antibiotic, yielding an activity of 519 U/mL. To increase the expression of AmyM, the promoter of amyM (gene encoding AmyM) was optimized. Furthermore, we found that excessive expression of dal gene was detrimental to the stability of plasmid, and the ribosome binding site (RBS) of dal was mutated with the reduced synthesis of D-alanine. After that, AmyM activity increased to 1364 U/mL with the 100 % stability of plasmid. The 3-L fermentor cultivation was performed with the highest value ever reported in food-grade microorganisms, an activity of 2388 U/mL, showing the scale-up production capability of this system. Besides, it is also able to apply the system for other food enzymes, which indicating the great generalizability of this system for different application.

Challenges and prospects of microbial α-amylases for industrial application: a review

α-Amylases are essential biocatalysts representing a billion-dollar market with significant long-term global demand. They have varied applications ranging from detergent, textile, and food sectors such as bakery to, more recently, biofuel industries. Microbial α-amylases have distinct advantages over their plant and animal counterparts owing to generally good activities and better stability at temperature and pH extremes. With the scope of applications expanding, the need for new and improved α-amylases is ever-growing. However, scaling up microbial α-amylase technology from the laboratory to industry for practical applications is impeded by several issues, ranging from mass transfer limitations, low enzyme yields, and energy-intensive product recovery that adds to high production costs. This review highlights the major challenges and prospects for the production of microbial α-amylases, considering the various avenues of industrial bioprocessing such as culture-independent approaches, nutrient optimization, bioreactor operations with design improvements, and product down-streaming approaches towards developing efficient α-amylases with high activity and recyclability. Since the sequence and structure of the enzyme play a crucial role in modulating its functional properties, we have also tried to analyze the structural composition of microbial α-amylase as a guide to its thermodynamic properties to identify the areas that can be targeted for enhancing the catalytic activity and thermostability of the enzyme through varied immobilization or selective enzyme engineering approaches. Also, the utilization of inexpensive and renewable substrates for enzyme production to isolate α-amylases with non-conventional applications has been briefly discussed.

Rab7 localized on zymogen granules is involved in maturation but not in autophagy or regulated exocytosis in pancreatic acinar cells

Rab7 is known to function in the autophagy and endocytosis pathways in eukaryocytes and is related to various diseases. We recently reported that Rab7 plays a protective role against acute pancreatitis. However, its physiological function in exocytic cells remains unclear. Therefore, we investigated the role of Rab7 in pancreas-specific Rab7 knockout mice (Rab7Δpan). Immunofluorescence microscopy revealed that Rab7 colocalized with amylase in pancreatic acinar cells of wild-type mice, but not in Rab7Δpan mice. Western blotting confirmed Rab7 localization in the zymogen granule (ZG) membranes of wild-type mice. Cholecystokinin (CCK)-stimulated amylase secretion examined using isolated pancreatic acini was similar in Rab7Δpan and wild-type mice. In contrast, electron microscopy revealed that the diameters of ZGs were shorter and the number of ZGs was larger in the pancreatic acinar cells of Rab7Δpan mice than in those of wild-type mice. However, the number of ZGs decreased in both Rab7Δpan and wild-type mice after 24 h of starvation. In addition, the amount of amylase in the pancreas was decreased in both Rab7Δpan and wild-type mice. These data indicate that Rab7 localized on ZGs plays a crucial role in the maturation of ZGs but not in their autophagy or regulated exocytosis in pancreatic acinar cells.

Supplementation of amylase or amylase + xylanase improves performance and metabolism of broilers fed with diets containing newly harvested maize

How supplementation with amylase or amylase + xylanase in newly harvested maize-based diets affects broiler nutrient metabolism and performance is unclear. Thus, this study evaluated whether the supplementation of amylase (CN) or amylase + xylanase (CAX) improves performance and metabolism of broilers fed with newly harvested maize-based diets during a 6-week production. The results showed that the body weight gain of broilers fed with CA or CAX diet was higher than that with the control (CN) diet at 1-21 d of age; however, an opposite trend was observed for feed/gain (p < 0.05). Furthermore, 150, 64 and 35 different metabolites were found between CA/CN, CAX/CN and CAX/CA, respectively. Overall, amylase supplementation improved broiler growth performance at 1-21 d of age, and the positive effects of amylase on nutrient utilization were mostly related to nicotinate, retinol and glutathione metabolism improvement. Moreover, CAX diet increased apparent metabolizable energy and growth performance of broilers at 22-42 d of age, and the difference might be related to sphingolipid, porphyrin and chlorophyll metabolism regulation. The findings prove amylase + xylanase supplementation is an effective method to improve the nutritional value of newly harvested maize for broilers.

Purification and characterization of amylases from three freshwater fish species providing new insight application as enzyme molecular markers for zymography

Purification of amylases from digestive tracts of three freshwater fish species with Q-Sepharose Fast Flow and Sephacryl S-200 columns displayed two isoforms of amylases from Osteochilus hasselti (O1, O2) and three isoforms of those from both Hampala dispar (UB, H1, H2) and Puntioplites proctozystron (P1, P2, P3). The optimum pH values displayed at 7.0 and 8.0, while the optimum temperatures revealed at 40 and 50 °C. Almost isoenzyme activities were activated by NaCl and CaCl2, whereas EDTA and SDS strongly inhibited all enzymatic activities. Verification with an atomic absorption spectrophotometry exhibited the presence of Ca2+ ions in the range of 0.02-13.53 ppm per mg protein indicating that amylases are Ca2+ dependent. Molecular weight analysis revealed 12 to 147 kDa. The UB, O1, and H2 amylases with appropriate molecular masses of 64, 49, and 25 kDa validated with LC-MS/MS were selected. Three certain enzymes revealed high stability in a sample buffer after five cycles of freeze-thawing process upon storage at - 20 °C for 12 weeks. No protein degradation was observed on polyacrylamide gel, and the enzymes still displayed sharp and clear bands on zymograms. The result suggested that the purified fish amylases, which expressed high activities and stabilities, were potentially used as enzyme molecular weight markers for zymography.

The cholinesterase and C-reactive protein score is a potential predictor of pseudoaneurysm formation after pancreaticoduodenectomy in patients with soft pancreas

BACKGROUND

Pseudoaneurysm (PA) rupture after pancreaticoduodenectomy (PD) is a life-threatening complication. Most PA cases originate from postoperative pancreatic fistulas (POPFs). Although several risk factors for POPF have been identified, specific risk factors for PA formation remain unclear. Therefore, we retrospectively analyzed PD cases with soft pancreas and proposed a novel strategy for early detection of PA formation.

METHODS

Overall, 120 patients underwent PD between 2010 and 2020 at our institution; of these, 65 patients with soft pancreas were enrolled. We evaluated the clinicopathological factors influencing PA formation and developed a risk score to predict PA formation.

RESULTS

In total, 11 of the 65 patients developed PAs (PA formation group: PAG), and 8 of these 11 PAs ruptured. The median time to PA formation was 15 days, with a minimum of 5 days. The PAG was significantly older than the non-PA formation group, were predominantly men, and had comorbid diabetes mellitus. Pre- and intra-operative findings were similar between the two groups. Importantly, no significant differences were found in postoperative drain amylase levels and total drain amylase content. Cholinesterase and C-reactive protein (CRP) levels on postoperative day (POD) 3 were significantly different between the two groups. Multivariate analysis showed that cholinesterase ≤ 112 U/L and CRP ≥ 16.0 mg/dl on POD 3 were independent predictors of PA formation.

CONCLUSIONS

Decreased cholinesterase and elevated CRP on POD 3 (Cho-C score) are useful predictors of PA formation in cases with soft pancreas. In such cases, periodic computed tomography evaluations and strict drain management are necessary to prevent life-threatening hemorrhage.

Analysis of biochemical parameters in an experimental model of chronic pancreatitis in rats

BACKGROUND

Despite advanced research and great progress in understanding the chronic pancreatitis (CP) pathogenesis, no current causal treatment for the condition is available. For preclinical studies, the existence of a well-characterized CP animal model is essential. The aim of the study was to assess the impact of chronic pancreatitis on the antioxidant enzymes activity in rat blood serum and on the level of glutathione (intracellular antioxidant) in rat pancreas.

METHODS

The experiments were carried out on the Wistar Kyoto rats in two groups: control and study group (CP), in which chemical induction of pancreatitis with dibutyl dichloride was performed. Serum enzyme activities of amylase, lipase, catalase and superoxide dismutase were analyzed. The levels of the following biochemical parameters were also investigated: total protein, albumin, calcium, magnesium, and triglycerides. Levels of low-molecular-weight thiols: reduced (GSH) and oxidized (GSSG) glutathione, were determined in pancreatic homogenates.

RESULTS

Histopathological imaging of rat pancreatic parenchyma with induced inflammation confirmed focal lymphocytic interstitial chronic pancreatitis with fibrosis features and mild parenchymal atrophy, as well as pancreatic islets degeneration. In the CP group, we observed a statistically significant decrease in serum amylase and lipase activities and in total protein/albumin levels. Also, the elevated catalase activity was registered. In CP rats' tissues, we observed a 15-fold reduction in GSH levels. The other examined parameters remained unchanged. Clinically relevant are hypoalbuminemia and a moderate decrease in lipase activity. The described changes are most probably indicative of the impaired exocrine pancreas function, however without organ failure features.

Comparative Evaluation of Salivary Parameters in Tobacco Substance Abusers

BACKGROUND

Tobacco use by youth is ever-demanding, and it is increasingly distributed not only in India but also globally. Saliva is a complex oral bio-fluid, freely available, performing absolute tasks for maintaining oral health and homeostasis. It contains a plethora of significant constituents such as proline-rich proteins (PRPs), immunoglobulins, IgA, enzymes lysozyme, lactoferrin, peroxidases, amylase, etc. The basic ecological balance of the oral cavity is stabilized via salivary clearance by reduced aggregation and adherence of microorganisms by direct microbial activity. This balance of oral activity is also done by indirect mechanisms by immunological as well as non-immunological means and also by effectively regulating salivary pH flow rate. This institutional observational study was planned to assess and compare salivary parameters (pH, salivary flow rate), total proteins, α-amylase, calcium, phosphate, and IgA, of unstimulated whole saliva of both tobacco abusers and tobacco non-users.

METHODS

The Study consisted of 270 participants (Tobacco habit) group, n = 135 and Control (Healthy) group, n = 135 and were in the age range of 20-50 years. They were assessed for oral health status, followed by the analysis of salivary pH, flow rate, total proteins, amylase, calcium, phosphates, and IgA of unstimulated whole saliva.

RESULTS

Comparative evaluation of salivary parameters among groups found that varying tobacco abusers had increased salivary amylase, protein levels, and phosphate whereas decreased salivary pH, flow rate, IgA, and in the whole unstimulated saliva samples than those of non-tobacco users. This difference among groups was statistically significant. (p < 0.05), and calcium levels were not altered significantly.

CONCLUSIONS

This study concludes that salivary parameters are altered in tobacco abusers when compared to those of non-abusers, and it was more significant in smokeless tobacco abusers than in any other form of tobacco abuse.

Protein secretion zones during overexpression of amylase within the Gram-positive cell wall

BACKGROUND

Whereas the translocation of proteins across the cell membrane has been thoroughly investigated, it is still unclear how proteins cross the cell wall in Gram-positive bacteria, which are widely used for industrial applications. We have studied the secretion of α-amylase AmyE within two different Bacillus strains, B. subtilis and B. licheniformis.

RESULTS

We show that a C-terminal fusion of AmyE with the fluorescent reporter mCherry is secreted via discrete patches showing very low dynamics. These are visible at many places within the cell wall for many minutes. Expression from a high copy number plasmid was required to be able to see these structures we term "secretion zones". Zones corresponded to visualized AmyE activity on the surface of cells, showing that they release active enzymes. They overlapped with SecA signals but did not frequently co-localize with the secretion ATPase. Single particle tracking showed higher dynamics of SecA and of SecDF, involved in AmyE secretion, at the cell membrane than AmyE. These experiments suggest that SecA initially translocates AmyE molecules through the cell membrane, and then diffuses to a different translocon. Single molecule tracking of SecA suggests the existence of three distinct diffusive states of SecA, which change during AmyE overexpression, but increased AmyE secretion does not appear to overwhelm the system.

CONCLUSIONS

Because secretion zones were only found during the transition to and within the stationary phase, diffusion rather than passive transport based on cell wall growth from inside to outside may release AmyE and, thus, probably secreted proteins in general. Our findings suggest active transport through the cell membrane and slow, passive transition through the cell wall, at least for overexpressed proteins, in bacteria of the genus Bacillus.

Changes in digestive enzyme activities during the early ontogeny of milkfish, Chanos chanos larvae

Knowledge of the developmental ontogeny of the digestive system and nutritional requirements of marine fish larvae is a primary requisite for their successful rearing under an optimal feeding regime. In this context, we assessed the activity profile of key digestive enzymes viz., trypsin, chymotrypsin, leucine aminopeptidase, lipase, amylase, and alkaline phosphatase during the early ontogeny of milkfish, Chanos chanos (0 day, 3 days, 6 days, 9 days, 12 days, 15 days, 18 days, 21 days, 25 days, and 30 days post-hatch). Larvae for this study were obtained from the successful breeding of milkfish at ICAR-Central Institute of Brackishwater Aquaculture, India. Growth curves (length and weight) of the larvae indicated a positive morphological development under a standardized feeding regime that comprised Chlorella salina, Brachionus plicatilis, Artemia salina nauplii, and commercial weaning feed for different larval stages. With respect to protein digestion, the specific activity of pancreatic enzymes trypsin and chymotrypsin and intestinal brush border leucine aminopeptidase showed two peaks at 3 dph and 15 dph, following the introduction of rotifer and Artemia nauplii. Similar bimodal peaks were observed for alkaline phosphatase and amylase activities, with the first peak at 3 dph and the second peak at 18 dph and 21 dph, respectively. Whereas in the case of lipase, high activity levels were observed at 0 dph, 3 dph, and 18 dph, with subsequent decreases and fluctuations. Overall, as most of the enzymes were found to have peak activities at 15 to 21 dph, this period can be potentially considered as the developmental window for weaning larvae from live to formulated feeds in milkfish hatcheries.

The effects of eugenol on histological, enzymatic, and oxidative parameters in the major salivary glands and pancreas of healthy male Wistar rats

OBJECTIVE

We evaluated the effects of eugenol on histological, enzymatic, and oxidative parameters in the pancreas, parotid, submandibular, and sublingual glands of healthy male rats.

DESIGN

Twenty-four adult Wistar rats were assigned into four groups (n = 6/group). Control rats received 2% Tween-20 (eugenol vehicle), whereas the other animals received 10, 20, and 40 mg kg-1 eugenol through gavage daily for 60 d. Major salivary and pancreatic glands were weighed and preserved fixed for microscopic analysis and frozen for in vitro assays.

RESULTS

Eugenol did not alter glands' weight and serum amylase activity regardless of the concentration. The highest dose of eugenol caused an increase in pancreatic amylase activity and a reduction of lipase activity from serum and pancreas. Eugenol at 40 mg kg-1 diminished the activity of SOD and FRAP in the submandibular gland and CAT and FRAP in the sublingual gland. However, it did not exert any effect on GST regardless of the gland. Additionally, 40 mg kg-1 eugenol increased MDA levels in pancreatic, parotid, and submandibular glands and NO levels in the sublingual. The concentrations of eugenol induced distinct responses in the glands regarding the activity of Na+/K+, Mg2+, and total ATPase activity. They also affected histomorphometrical and histochemistrical parameters in the submandibular gland only.

CONCLUSIONS

Results indicated that 40 mg kg-1 eugenol altered most of the biochemical and oxidatived parameters of digestive glands. Only submandibular glands presented histological changes after eugenol exposure suggesting potential implications for its function.

Nonalcoholic fatty liver disease aggravates acute pancreatitis through bacterial translocation and cholesterol metabolic dysregulation in the liver and pancreas in mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for severe acute pancreatitis (AP). The underlying mechanism remains unclear. We sought to determine how bacterial translocation and cholesterol metabolism in the liver and pancreas affect the severity of AP in NAFLD mice.

METHODS

C57BL/6N mice were fed on a high-fat diet (HFD) to generate the NAFLD model, and mice in the control group were provided with a normal diet (ND). After being anesthetized with ketamine/xylazine, mice got a retrograde infusion of taurocholic acid sodium into the pancreatic duct to induce AP, and sham operation (SO) was used as control. Serum amylase and Schmidt's pathological score system were used to evaluate AP severity. Bacterial loads, total cholesterol level, and cholesterol metabolic-associated molecules [low-density lipoprotein receptor (LDLR) and ATP-binding cassette transporter A1 (ABCA1)] were analyzed in the liver and pancreas.

RESULTS

Compared with the ND-AP group, mice in the HFD-AP group had severer pancreatitis, manifested with higher serum amylase levels and higher AP pathologic scores, especially the inflammation and hemorrhage scores. Compared with the HFD-SO group and ND-AP group, bacterial loads in the liver and pancreas were significantly higher in the HFD-AP group. Mice in the HFD-AP group showed a decreased LDLR expression and an increased ABCA1 expression in the pancreas, although there was no significant difference in pancreas total cholesterol between the HFD-AP group and the ND-AP group.

CONCLUSIONS

NAFLD aggravates AP via increasing bacterial translocation in the liver and pancreas and affecting pancreas cholesterol metabolism in mice.

Exploring the interactive mechanism of acarbose with the amylase SusG in the starch utilization system of the human gut symbiont Bacteroides thetaiotaomicron through molecular modeling

The α-amylase, SusG, is a principal component of the Bacteroides thetaiotaomicron (Bt) starch utilization system (Sus) used to metabolize complex starch molecules in the human gastrointestinal (GI) tract. We previously reported the non-microbicidal growth inhibition of Bt by the acarbose-mediated arrest of the Sus as a potential therapeutic strategy. Herein, we report a computational approach using density functional theory (DFT), molecular docking, and molecular dynamics (MD) simulation to explore the interactive mechanism between acarbose and SusG at the atomic level in an effort to understand how acarbose shuts down the Bt Sus. The docking analysis reveals that acarbose binds orthosterically to SusG with a binding affinity of -8.3 kcal/mol. The MD simulation provides evidence of conformational variability of acarbose at the active site of SusG and also suggests that acarbose interacts with the main catalytic residues via a general acid-base double-displacement catalytic mechanism. These results suggest that small molecule competitive inhibition against the SusG protein could impact the entire Bt Sus and eliminate or reduce the system's ability to metabolize starch. This computational strategy could serve as a potential avenue for structure-based drug design to discover other small molecules capable of inhibiting the Sus of Bt with high potency, thus providing a holistic approach for selective modulation of the GI microbiota.

Large scale microfluidic CRISPR screening for increased amylase secretion in yeast

Key to our ability to increase recombinant protein production through secretion is a better understanding of the pathways that interact to translate, process and export mature proteins to the surrounding environment, including the supporting cellular machinery that supplies necessary energy and building blocks. By combining droplet microfluidic screening with large-scale CRISPR libraries that perturb the expression of the majority of coding and non-coding genes in S. cerevisiae, we identified 345 genes for which an increase or decrease in gene expression resulted in increased secretion of α-amylase. Our results show that modulating the expression of genes involved in the trafficking of vesicles, endosome to Golgi transport, the phagophore assembly site, the cell cycle and energy supply improve α-amylase secretion. Besides protein-coding genes, we also find multiple long non-coding RNAs enriched in the vicinity of genes associated with endosomal, Golgi and vacuolar processes. We validated our results by overexpressing or deleting selected genes, which resulted in significant improvements in α-amylase secretion. The advantages, in terms of precision and speed, inherent to CRISPR based perturbations, enables iterative testing of new strains for increased protein secretion.

Incidence and risk factors of postoperative hyperamylasemia and pancreatitis following total knee arthroplasty: a retrospective study

BACKGROUND

Postoperative hyperamylasemia and pancreatitis are recognized complications after abdominal and spinal surgeries. The aim of this study is to investigate the incidence and identify risk factors for postoperative hyperamylasemia and pancreatitis following total knee arthroplasty.

METHODS

170 patients undergoing total knee arthroplasty were retrospectively identified from our database from January 2017 to January 2021. Patients were divided into normal and hyperamylasemia groups based on the presence of serum amylase level within or greater than the normal range. The diagnosis of postoperative pancreatitis was based on the 2012 revised Atlanta Classification of Acute Pancreatitis. Patient demographics, perioperative parameters were investigated with student t test, chi square test and multivariate logistic regression analysis.

RESULTS

43 patients (25.3%) exhibited postoperative hyperamylasemia while eight patients (4.7%) exhibited serum amylase < 5 times the normal upper limit. One patient (0.6%) was designated as having postoperative pancreatitis. More patients with Hypertriglyceridemia (HTG) were noted in hyperamylasemia group (P = 0.009) compared with normal group. Hyperamylasemia group showed higher preoperative serum amylase (74.95 vs. 55.62 IU/L, P < 0.001), higher intra-operative blood loss (IBL) (117.67 vs. 77.01 mL, P = 0.040) and longer surgical duration (132.98 vs. 107.01 min, P = 0.041). Multivariate logistic analysis revealed that HTG (OR = 0.189, P = 0.006), preoperative serum amylase (OR = 1.042, P < 0.001) and IBL (OR = 1.004, P = 0.022) were independent risk factors for postoperative hyperamylasemia.

CONCLUSIONS

A significant percentage of patients developed hyperamylasemia after total knee arthroplasty. Patients with HTG, higher preoperative serum amylase and higher IBL had an increased risk of developing postoperative hyperamylasemia and pancreatitis.

C-reactive protein postoperative values to predict clinically relevant postoperative pancreatic fistula after distal pancreatectomy

INTRODUCTION

despite significant medical and technological advances, the incidence of postoperative pancreatic fistula (POPF) after distal pancreatectomy (DP) is reported to be between 3-45 %. The main objective of this study was to analyze the early post-surgical risk factors for developing POPF after DP.

MATERIAL AND METHODS

a retrospective observational study was performed on a prospective basis of patients undergoing DP in a tertiary hospital from January 2011 to December 2021. Sociodemographic, preoperative analytical, tumor-related and postoperative complications variables were analyzed.

RESULTS

of the 52 patients analyzed, 71.8 % of the sample had postoperative drains amylase elevation. However, 25.7 % of the total had grade-B and/or grade-C POPF. Univariate logistic regression with the variables studied showed the following as risk factors for B-C or clinically relevant POPF: amylase values in drainage at the 5th postoperative day (POD) (p = 0.097; 1.01 [1-1.01]), preoperative BMI (p = 0.015; 1.27 [1.04-1.55]) and C-reactive protein (CRP) value at the 3rd POD (p = 0.034; 1.01 [1.01-1.02]). The ROC curve of CRP value at the 3rd POD showed an area under the curve of 0.764 (95 % CI: 0.6-0.93) and the best cut-off point was 190 mg/l (sensitivity 89 % and specificity 67 %).

CONCLUSIONS

CRP value at the 3rd POD is a predictive factor for POPF after DP. Early detection of patients at risk of POPF based on these characteristics could have an impact on their postoperative management.

Optimal timing of free total rhubarb anthraquinones on immune regulation in rats with severe acute pancreatitis

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb is the peeled and dried root of Rheum palmatum L., Rheum tanguticum Maxim. ex Balf. or Rheum officinale Baill. Free total rhubarb anthraquinones (FTRAs) isolated and extracted from rhubarb display the beneficial effects of anti-inflammation and immunological modulation. The timing of immune regulation is a major problem in the immunotherapy for severe acute pancreatitis (SAP). several studies reported that FTRAs could reduce systemic inflammatory responses by inhibiting early immune overactivity in the gut in rats with SAP. But, the optimal timing of rhubarb and FTRAs administration is not clear in clinical practice. Therefore, the time window for the best efficacy of rhubarb and FTRAs in the treatment of SAP patients should be further elucidated.

AIM OF THE STUDY

The main purpose of the present study was to evaluate the efficacy and optimal timing of immune modulation with FTRAs in the treatment of SAP in rats.

MATERIALS AND METHODS

FTRAs (22.5, 45 and 90 mg/kg), Rhubarb (RHU) (900 mg/kg, positive control) or normal saline (vehicle control) were initiated at 0 (immediately), 48 and 72 h every 12 h for three times in total. The therapeutic effects of FTRAs and RHU on pancreas and intestinal tissues injury, secondary infection with pseudomonas aeruginosa (PA), amylase, lipase, D-lactic acid (DLA), endotoxin (ET), proinflammatory and anti-inflammatory cytokines, macrophages, dendritic cells and regulatory T cells (Tregs) in the blood, small intestine and/or mesenteric lymph node (MLN) were determined in rats with SAP after treatment.

RESULTS

The results showed that administration of FTRAs at 0 h was superior to 48 h and 72 h, which significantly protected the injury of pancreas and intestinal tissues, reduced the mortality induced by secondary infection with PA, decreased the levels of amylase, lipase, DLA, ET, tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), IL-6, IL-8, IL-18 and Tregs, and increased the levels of IL-4, sTNF-αR, macrophages and dendritic cells, secretary immunoglobulin A (SIgA) in the blood and/or small intestinal tissues in rats with SAP.

CONCLUSIONS

In conclusion, our studies indicate that the treatment window of FTRAs for SAP is within 48 h of development, administration of FTRAs at the early stage (0 h, immune overreaction period) was the optimal time and superior to that of 48 h and 72 h for its therapeutic efficacy. The earlier the administration of FTRAs, the better the therapeutic efficacy. Therefore, our data may provide a scientific rationale for the clinical application and optimal timing of FTRAs in the treatment of SAP.

Evaluation of Biological Activities of Twenty Flavones and In Silico Docking Study

This work aimed to evaluate the biological activities of 20 flavones (M1 to M20) and discuss their structure–activity relationships. In vitro assays were established to assess their numerous biological activities (anti-α-amylase, anti-acetylcholinesterase, anti-xanthine oxidase, anti-superoxide dismutase, and anticancer cell lines (HCT-116, MCF7, OVCAR-3, IGROV-1, and SKOV-3 cells lines)). An in silico docking study was also established in order to find the relationship between the chemical structure and the biological activities. In vitro tests revealed that M5 and M13 were the most active in terms of anti-α-amylase activity (IC50 = 1.2 and 1.4 µM, respectively). M17 was an inhibitor of xanthine oxidase (XOD) and performed better than the reference (allopurinol), at IC50 = 0.9 µM. M7 presented interesting anti-inflammatory (IC50 = 38.5 µM), anti-supriode dismutase (anti-SOD) (IC50 = 31.5 µM), and anti-acetylcholinesterase (IC50 = 10.2 µM) activities. Those abilities were in concordance with its high scavenging activity in antioxidant ABTS and DPPH assays, at IC50 = 6.3 and 5.2 µM, respectively. Selectivity was detected regarding cytotoxic activity for those flavones. M1 (IC50 = 35.9 µM) was a specific inhibitor to the MCF7 cancer cell lines. M3 (IC50 = 44.7 µM) and M15 (IC50 = 45.6 µM) were particularly potent for the OVCAR-3 cell line. M14 (IC50 = 4.6 µM) contributed more clearly to inhibiting the colon cancer cell line (HCT116). M7 (IC50 = 15.6 µM) was especially active against the ovarian SKOV human cancer cell line. The results of the biological activities were supported by means of in silico molecular docking calculations. This investigation analyzed the contribution of the structure–activity of natural flavones in terms of their biological properties, which is important for their future application against diseases.

Promoter-proximal introns impact recombinant amylase expression in Saccharomyces cerevisiae

Consolidated bioprocessing (CBP) of starch requires recombinant Saccharomyces cerevisiae strains that produce raw starch-degrading enzymes and ferment the resultant sugars to ethanol in a single step. In this study, the native S. cerevisiae COX4 and RPS25A promoter-proximal introns were evaluated for enhanced expression of amylase genes (ateA, temA or temG_Opt) under the control of an S. cerevisiae promoter (ENO1P, TEF1P, TDH3P, or HXT7P). The results showed that different promoters and promoter-intron combinations differentially affected recombinant amylase production: ENO1P-COX4i and TDH3P-RPS25Ai were the best promoters for AteA, followed closely by HXT7P. The latter was also the best promoter for TemA and TemG production, followed closely by TDH3P-RPS25Ai for both these enzymes. Introducing promoter-proximal introns increased amylase activity up to 62% in Y294[ENO-COX-AteA] and Y294[TDH3-RPS-TemA], a significant improvement relative to the intron-less promoters. Strains co-expressing both an α-amylase and glucoamylase genes yielded up to 56 g/L ethanol from 20% w/v raw starch, with a higher carbon conversion observed with strains co-expressing TDH3P-RPS25Ai-temG_Opt than HXT7P-temG_Opt. The study showed that promoter-proximal introns can enhance amylase activity in S. cerevisiae and suggest that these alternative cassettes may also be considered for expression in more efficient ethanol-producing industrial yeast strains for raw starch CBP.

High carbohydrate increases amylase, plasma glucose, and gene expression related to glycolysis in giant gourami Osphronemus goramy

The present study elucidated hepatic molecular and physiological responses of giant gourami to high dietary carbohydrates. Two levels of dietary carbohydrate, normal carbohydrate (34%, NC) and high carbohydrate (53%, HC), were offered to the fish for 60 days. We evaluated the expression of genes that are related to carbohydrate metabolism, lipogenic capacities, amino acid catabolism, Krebs cycle, and energy sensing. In addition, we also observed the digestive enzyme activities, plasma glucose, glycogen content, whole-body composition, and growth performance of the fish. On day 30 after treatment, fish fed with high dietary carbohydrate level has significantly higher expression of gck, pk, hk, and ldh than the NC group (P < 0.05). In contrast, fish in the HC group had lower expression of irs1, igf-1, sdh, fbp, g6pc, gyp, and ampk compared to the NC fish (P < 0.05). On day 60 of the feeding trial, gck and hk expressions were still higher in the HC group (P < 0.05), and gyp, gdh, and ampk became increasingly expressed in the HC group. The increase of dietary carbohydrates resulted in significant increases in amylase and protease activity, plasma glucose, liver glycogen, crude protein, and lipid contents of the fish whole-body (P < 0.05). The high carbohydrate feeding reduced the fish growth rate but increased feed efficiency and did not affect mortality. In conclusion, giant gourami could utilize high carbohydrates due to a high amylase secretion, high modulation of carbohydrate metabolism, and large glucose storage capacity.

Toxicity of chronic waterborne zinc exposure in the hepatopancreas of white shrimp Litopenaeus vannamei

Zinc (Zn) is necessary for the survival of aquatic organisms; nevertheless, the accumulation of Zn in excessive amounts may have toxic consequences. Few studies focusing on the biochemical, morphological, and transcriptional effects of aqueous Zn in Litopenaeus vannamei have been reported, and the underlying toxic mechanism remains largely unknown. The present study was performed to investigate the growth performance, morphological alterations, physiological changes, and transcriptional responses after Zn exposure at 0 (control), 0.01, 0.1, and 1 mg/L concentrations for 30 days in white shrimp L. vannamei hepatopancreas. The results found that survival rate (SR) and growth performance were significantly reduced in 1 mg/L Zn group. Significant structural damage and significant Zn accumulation in hepatopancreas were observed. The activities of trypsin and amylase (AMS), and the total antioxidant capacity (T-AOC) were attenuated, while the production of reactive oxygen species (ROS) and malondialdehyde (MDA) content were significantly increased after Zn exposure. Many differentially expressed genes (DEGs) were obtained after Zn exposure, and the majority of these DEGs were downregulated. Ten DEGs involved in oxidative stress, immunological response, apoptosis, and other processes were selected for qRT-PCR validation and the expression profiles of these DEGs kept well consistent with the transcriptome data, which confirmed the accuracy and reliability of the transcriptome results. Subsequently, we screened 12 genes to examine the changes of expression in different concentrations in more detail. All the results implying that Zn exposure caused severe histopathological changes and increased Zn accumulation in hepatopancreas, altered immune, antioxidant and detoxifying response by regulating the gene expressions of related genes, and eventually might trigger apoptosis. These findings provide valuable information and a new perspective on the molecular toxicity of crustaceans in response to environmental heavy metal exposure.

MicroRNA-320-3p promotes the progression of acute pancreatitis by blocking DNMT3a-mediated MMP8 methylation in a targeted manner

In this research, we screened out two genes upregulated in mice with acute pancreatitis (AP) by gene sequencing: microRNA (miR)-320-3p and matrix metalloprotease 8 (MMP8). This study was designed to determine whether miR-320-3p and MMP8 participate in AP development and explore the mechanisms, with a new idea for clinical diagnosis and treatment of AP. Expression of miR-320-3p, DNA methyltransferase 3a (DNMT3a), and MMP8 in mouse pancreatic tissues and AR42J cells was tested by RT-qPCR and western blot assays. Pancreatic pathological changes, serum amylase and lipase, and inflammatory factors in mouse serum and cell supernatant were measured by hematoxylin-eosin staining, automation analyzer, and enzyme-linked immunosorbent assay, respectively. Cell proliferation and apoptosis were determined by CCK-8 assay and flow cytometry. The interaction between miR-320-3p, DNMT3a, and MMP8 was verified by luciferase activity assay, ChIP-qPCR, and MSP assay. High expression of miR-320-3p and MMP8, and low expression of DNMT3a were observed in pancreatic tissues of AP mice and caerulein-induced AP cellular model. Downregulation of miR-320-3p alleviated injury of mouse pancreas, reduced the levels of serum amylase and lipase, and blocked inflammatory factor levels in AP mice. In caerulein-induced AP cellular models, inhibiting miR-320-3p facilitated proliferation and inhibited apoptosis. Upregulation of MMP8 resulted in the opposite results, which could be reversed by simultaneous inhibition of miR-320-3p. miR-320-3p targeted DNMT3a, and downregulating miR-320-3p promoted DNMT3a expression. Moreover, DNMT3a promoted DNA methylation in MMP8 promoter region, thereby inhibiting MMP8 expression in AP mouse and cellular models. This research suggests that miR-320-3p inhibits DNMT3a to reduce MMP8 methylation and increase MMP8 expression, thereby promoting AP progression.

Improving the Product Specificity of Maltotetraose-Forming Amylase from Pseudomonas saccharophila STB07 by Removing the Carbohydrate-Binding Module

Maltotetraose (G4) is composed of four glucose units linked by the α-1,4-glycosidic bond, which has excellent adaptability in food processing and specific physiological functions. Maltotetraose-forming amylases (MFAses) are used in the industry as a promising tool for G4 production. The MFAse from Pseudomonas saccharophila STB07 (MFA_PS), which belongs to the GH13, can preferentially hydrolyze substrates to G4. MFA_PS contains a carbohydrate-binding module (CBM). In this study, we removed the CBM to obtain the mutant MFA_PS-ΔCBM. We explored the aspects affecting the catalytic performance of enzymes through structural simulations and molecular docking. Results showed that when the CBM was removed, the thermal stability of MFA_PS was slightly reduced, and its catalytic ability for long-chain substrates, such as corn starch, was significantly reduced. However, the catalytic ability and product specificity of the substrates with shorter chain length, such as maltodextrin (DE 7-9), were improved. The G1-G7 (glucose (G1), maltose (G2), maltotriose (G3), maltotetraose (G4), maltopentaose (G5), maltohexaose (G6), and maltoheptaose (G7)) contents and G4 proportion of the mutant MFA_PS-ΔCBM reaction at 24 h were 11.1 and 11.6% higher than those of MFA_PS, respectively. The results also showed that the forces of MFA_PS on the substrate near the -4, -1, +1, and +3 subsites were critical for its product specificity.

New Biologically Hybrid Pharmacophore Thiazolidinone-Based Indole Derivatives: Synthesis, In Vitro Αlpha-Amylase and Αlpha-Glucosidase Along with Molecular Docking Investigations

Amylase and glucosidase enzymes are the primary harmful source in the development of the chronic condition known as diabetes mellitus. The main function of these enzymes is to break the macromolecules into simple sugar units which are directly involved in the solubility of blood, hence increasing blood glucose levels. To overcome this effect, there is a need for a potent and effective inhibitor that inhibits the conversion of macromolecules of sugar into its smaller units. In this regard, we synthesized thiazolidinone-based indole derivatives (1−20). The synthesized derivatives were evaluated for α-amylase and α-glucosidase inhibitory activity. Different substituted derivatives were found with moderate to good potentials having IC50 values ranging, for α-amylase, from 1.50 ± 0.05 to 29.60 ± 0.40 μM and, for α-glucosidase, from IC50 = 2.40 ± 0.10 to 31.50 ± 0.50 μM. Among the varied substituted compounds, the most active analogs four (1.80 ± 0.70 and 2.70 ± 0.70), five (1.50 ± 0.05 and 2.40 ± 0.10, respectively) of the series showed few folds better inhibitory activity than standard drug acarbose (IC50 = 10.20 ± 0.10 and 11.70 ± 0.10 μM, respectively). Moreover, structure−activity relationship (SAR) was established and binding interactions were analyzed for ligands and proteins (α-amylase and α-glucosidase) through a molecular docking study.

Artificial consortia of Bacillus amyloliquefaciens HM618 and Bacillus subtilis for utilizing food waste to synthetize iturin A

Food waste is a cheap and abundant organic resource that can be used as a substrate for the production of the broad-spectrum antifungal compound iturin A. To increase the efficiency of food waste biotransformation, different artificial consortia incorporating the iturin A producer Bacillus amyloliquefaciens HM618 together with engineered Bacillus subtilis WB800N producing lipase or amylase were constructed. The results showed that recombinant B. subtilis WB-A13 had the highest amylase activity of 23406.4 U/mL, and that the lipase activity of recombinant B. subtilis WB-L01 was 57.5 U/mL. When strain HM618 was co-cultured with strain WB-A14, the higher yield of iturin A reached to 7.66 mg/L, representing a 32.9% increase compared to the pure culture of strain HM618. In the three-strain consortium comprising strains HM618, WB-L02, and WB-A14 with initial OD₆₀₀ values of 0.2, 0.15, and 0.15, respectively, the yield of iturin A reached 8.12 mg/L, which was 38.6% higher than the control. Taken together, artificial consortia of B. amyloliquefaciens and recombinant B. subtilis can produce an increased yield of iturin A, which provides a new strategy for the valorization of food waste.

Effect of winter feeding frequency on growth performance, biochemical blood parameters, oxidative stress, and appetite-related genes in Takifugu rubripes

Tiger pufferfish (Takifugu rubripes) is one of Asia's most economically valuable aquaculture species. However, winter production of this species in North China is limited by low water temperature and unavailability of high-quality feed, resulting in high mortality and low profitability. Therefore, the aim of this study was to evaluate the effect of feeding frequency (F1: one daily meal; F2: two daily meals; F3: four daily meals; F4: continuous diurnal feeding using a belt feeder) on the growth performance, plasma biochemistry, digestive and antioxidant enzyme activities, and expression of appetite-related genes in T. rubripes (initial weight: 266.80 ± 12.32 g) cultured during winter (18.0 ± 1.0 °C) for 60 days. The results showed that fish in the F3 group had the highest final weight, weight gain rate, specific growth rate, survival rate, and best feed conversion ratio. Additionally, daily feed intake increased significantly with increasing feeding frequency. The protein efficiency and lipid efficiency ratios of fish in the F3 group were significantly higher than those of fish in the other groups. Furthermore, total cholesterol, triglycerides, and glucose levels increased with increasing feeding frequency, peaking in the F2 group and decreasing under higher feeding frequencies. The antioxidant (superoxide dismutase, catalase, glutathione, and glutathione peroxidase) and digestive (trypsin, amylase, and lipase) enzyme activities of fish in the F1 group were significantly higher than those of fish in the F3 and F4 groups. Additionally, there was a decrease in orexin expression with increasing feeding frequency. In contrast, the expression levels of tachykinin, cholecystokinin, and leptin increased with increasing feeding frequency, peaking in the F4 group. Overall, the findings of this study indicated that a feeding frequency of four meals per day was optimal for improved growth performance of pufferfish juveniles cultured during winter.

Effect of Exogenous Glycine Betaine on the Germination of Tomato Seeds under Cold Stress

Cold stress is known to influence tomato growth, development, and yield. In this study, we analyzed the germination of tomato seeds treated with exogenous glycine betaine (GB) at a low temperature (14 °C). The results showed that cold stress inhibited tomato seed germination, and pretreatment with exogenous GB reduced this inhibition and enhanced the germination rate (GR), germination index (GI), and viability of tomato seeds at low temperatures. Analysis of gene expression and metabolism revealed that GB positively regulated endogenous hormone gibberellin (GA) content and negatively regulated abscisic acid (ABA) content, while GB reduced the starch content in the seeds by up-regulating the amylase gene expression. Gene expression analysis showed that the key genes (SlSOD, SlPOD, and SlchlAPX) involved in reactive oxygen species (ROS) scavenging systems were up-regulated in GB-pretreated tomato seeds compared with the control. At the same time, levels of malondialdehyde and hydrogen peroxide were significantly lower, while the proline content and peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) levels were elevated compared with those in the control. These results demonstrate that exogenous GB as a positive regulator effectively alleviated the inhibition of tomato seed germination under cold stress by different signal pathways.

Acute toxic effects of thiamethoxam on Chinese mitten crab Eriocheir sinensis

The information about toxic effects of thiamethoxam on non-target aquatic organisms is still incomplete. The semi-static toxicity test method was used to investigate the acute toxic effects of thiamethoxam on Eriocheir sinensis. The results showed that the median lethal concentration (LC50) of thiamethoxam to E. sinensis at 96 h was 510 μg/L, and the safety concentration (SC) was 51 μg/L. After 96 h exposure to thiamethoxam, the survival rates of crabs at concentrations of 0, 151.11, 226.67, 340, and 510 μg/L were 100%, 76.19%, 64.29%, 61.91%, and 46.43%, respectively. A significant (P < 0.05) decrease of the number of hemocytes was observed in thiamethoxam groups. With the increase of thiamethoxam concentration, the phagocytic activity of hemocytes, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), and the activities of protease, amylase, and lipase of crabs increased firstly and then decreased, and the above indexes reached the maximum in 151.11 μg/L thiamethoxam group. Collectively, a high concentration of thiamethoxam (510 μg/L) had a great effect on the gene expression of immune metabolism-related factors in hepatopancreas and gill of crabs. These findings indicated that thiamethoxam exposure had the ability to impair immune and metabolic systems and resulted in the reduction of survival rate of crabs.

The temperature-dependent expression of type II secretion system controls extracellular product secretion and virulence in mesophilic Aeromonas salmonida SRW-OG1

Aeromonas salmonicida is a typical cold water bacterial pathogen that causes furunculosis in many freshwater and marine fish species worldwide. In our previous study, the pathogenic A. salmonicida (SRW-OG1) was isolated from a warm water fish, Epinephelus coioides was genomics and transcriptomics analyzed. Type II secretion system was found in the genome of A. salmonicida SRW-OG1, while the expressions of tatA, tatB, and tatC were significantly affected by temperature stress. Also, sequence alignment analysis, homology analysis and protein secondary structure function analysis showed that tatA, tatB, and tatC were highly conservative, indicating their biological significance. In this study, by constructing the mutants of tatA, tatB, and tatC, we investigated the mechanisms underlying temperature-dependent virulence regulation in mesophilic A. salmonida SRW-OG1. According to our results, tatA, tatB, and tatC mutants presented a distinct reduction in adhesion, hemolysis, biofilm formation and motility. Compared to wild-type strain, inhibition of the expression of tatA, tatB, and tatC resulted in a decrease in biofilm formation by about 23.66%, 19.63% and 40.13%, and a decrease in adhesion ability by approximately 77.69%, 80.41% and 62.14% compared with that of the wild-type strain. Furthermore, tatA, tatB, and tatC mutants also showed evidently reduced extracellular enzymatic activities, including amylase, protease, lipase, hemolysis and lecithinase. The genes affecting amylase, protease, lipase, hemolysis, and lecithinase of A. salmonicida SRW-OG1 were identified as cyoE, ahhh1, lipA, lipB, pulA, HED66_RS01350, HED66_RS19960, aspA, fabD, and gpsA, which were notably affected by temperature stress and mutant of tatA, tatB, and tatC. All above, tatA, tatB and tatC regulate the virulence of A. salmonicida SRW-OG1 by affecting biofilm formation, adhesion, and enzymatic activity of extracellular products, and are simultaneously engaged in temperature-dependent pathogenicity.

Research Note. Amylase supplementation improves starch and amino acids digestibility of faba bean for broilers

This study aimed to investigate the effect of amylase on the nutritional value and nitrogen-corrected apparent metabolizable energy (AME_N) of faba bean (FB) seeds in broiler chicken nutrition. The study was conducted on a total of 84, one-day-old male broiler chickens (Ross 308). The birds were fed a reference corn-soybean meal diet form d 1 to 16, and they were divided into three groups (1st day). The first group (1) was fed the same reference diet as in the first part, whereas 50% of the reference diet was replaced by FB seeds in experimental groups (2 and 3). Group 3 was supplemented with amylase, which contained 0.14 g/kg dry matter (DM). At the end of the study period, excreta and digesta samples were collected from all groups to estimate the nutritional value. Some fraction of starch found in the seeds was part of starch which is resistant to digestion (143.9 g/kg DM). The addition of exogenous amylase to the diet increased the apparent ileal digestibility of DM, CP, and starch in FB seeds. The AME_N value increased as a result of enzyme addition (P < 0.05). The group 3 showed higher apparent ileal digestibility of essential amino acids (Lys, Leu, Phe, His) as well as nonessential amino acids (Tyr, Ala, Pro) in FB seeds. It could be concluded that FB seeds supplemented with exogenous amylase have a greater nutrition value for broiler chickens.

Paeoniflorin Can Improve Acute Lung Injury Caused by Severe Acute Pancreatitis through Nrf2/ARE Pathway

Objective

To evaluate the potential therapeutic effect of paeoniflorin on acute lung injury induced by severe acute pancreatitis (SAP) and to initially explore the possible protective mechanisms of paeoniflorin.

Method

The SAP lung injury rat model was established by retrograde injection of 5% sodium taurocholate to the cholangiopancreatic duct. H&E staining was used to detect pathological changes in rat lung tissue. W/D ratio method, serum amylase (AMY), and lipase activity were used to assess the degree of lung injury in rats. Oxidation indicators such as LDH, MDA, and SOD in lung tissue were measured. Levels of inflammatory factors TNF-α, IL-6, and IL-10 were measured in bronchoalveolar lavage fluid (BALF). At the same time, Western blot was used to detect the expression of related proteins in the Nrf2/ARE signaling pathway.

Results

In SAP rats, paeoniflorin treatment could significantly alleviate lung injury conditions such as pulmonary edema and inflammatory cell infiltration in lung tissue and reduce serum amylase and lipase activities. Paeoniflorin can reduce the content of LDH and MDA in lung tissue and increase the content of SOD. In addition, ELISA results showed that paeoniflorin could inhibit the levels of TNF-α and IL-6 in BALF and upregulate the levels of IL-10. Paeoniflorin could upregulate the expression of Nrf2/ARE signaling pathway proteins Cyt-Nrf2, HO-1, and NQO1 in lung tissue of SAP rats.

Conclusion

Paeoniflorin may improve acute lung injury in rats with severe pancreatitis by inhibiting inflammation and oxidative stress response. These effects may be related to activating the Nrf2/ARE signaling pathway.

Programming an Orthogonal Self-Assembling Protein Cascade Based on Reactive Peptide-Protein Pairs for In Vitro Enzymatic Trehalose Production

Trehalose is an important rare sugar that protects biomolecules against environmental stress. We herein introduce a dual enzyme cascade strategy that regulates the proportion of cargos and scaffolds, to maximize the benefits of enzyme immobilization. Based upon the self-assembling properties of the shell protein (EutM) from the ethanolamine utilization (Eut) bacterial microcompartment, we implemented the catalytic synthesis of trehalose from soluble starch with the coimmobilization of α-amylase and trehalose synthase. This strategy improved enzymatic cascade activity and operational stability. The cascade system enabled the efficient production of trehalose with a yield of ∼3.44 g/(L U), 1.5 times that of the free system. Moreover, its activity was maintained over 12 h, while the free system was almost completely inactivated after 4 h, demonstrating significantly enhanced thermostability. In conclusion, an attractive self-assembly coimmobilization platform was developed, which provides an effective biological process for the enzymatic synthesis of trehalose in vitro.

Exocrine pancreas function is impaired in adult relatives of patients with type 1 diabetes

AIMS

Alterations of the exocrine pancreas have been reported in type 1 diabetes, but their contribution to the pathogenesis of the disease is poorly understood. Here, we investigated markers of exocrine pancreas dysfunction in individuals at-risk of developing type 1 diabetes.

METHODS

Serum P-amylase and lipase levels were assessed in samples obtained from healthy controls, patients with new onset type 1 diabetes, relatives participating to the TrialNet Pathway to Prevention who were, at blood collection, autoantibody negative or positive for a single autoantibody (low-risk individuals), and positive for multiple autoantibodies (high-risk individuals). Linear mixed models were adopted to estimate variation of pancreatic enzymes among the groups and to evaluate the influence of high-risk HLA genotypes and residual beta cell function on exocrine pancreas function.

RESULTS

In adults, but not children, reduced levels of P-amylase and lipase were shown in at-risk individuals, including (for P-amylase levels only) those at low-risk, and in T1Dnew. Furthermore, while high-risk HLA genotypes negatively affected P-amylase levels in autoantibody negative adult individuals, fasting C-peptide levels did not correlate with pancreatic enzyme levels.

CONCLUSIONS

Exocrine pancreas dysfunction precedes the onset of type 1 diabetes in adult at-risk individuals and may be unrelated to fasting C-peptide levels.

Effects of orchiectomy and testosterone replacement therapy on redox balance and salivary gland function in Wistar rats

The objective of this study was to investigate the effects of orchiectomy (ORX) and testosterone replacement therapy (TRT) on redox balance and function of salivary glands. Forty-five young adult male Wistar rats (3 months old) were either castrated bilaterally or underwent fictitious surgery (SHAM) and were subsequently distributed into 3 groups: SHAM, ORX, and TRT (castrated rats that received an intramuscular injection of testosterone cypionate 10 mg/kg/weekly). All treatments started 4 weeks after castration (4 months old) and lasted 4 weeks (5 months old). At the end of treatment, pilocarpine-induced salivary secretion was collected to analyze salivary flow rate and biochemistry composition, and the parotid (PG) and submandibular (SMG) glands were sampled for redox balance markers and histomorphometric analyses. ORX increased salivary flow rate, calcium, phosphate, and chloride, and decreased total protein and amylase, while not changing the salivary buffer capacity, pH, sodium, and potassium compared to SHAM. TRT restored all salivary parameters to SHAM values. ORX increased oxidative lipid and protein damage, total antioxidant capacity, and uric acid in both salivary glands compared to SHAM. Superoxide dismutase, catalase, and glutathione peroxidase activities were greater only in the SMG of the ORX group in relation to SHAM. ORX decreased duct and acini area, while increasing connective tissue in the PG. On the other hand, ORX reduced duct area and increased acini area in the SMG compared to SHAM. TRT restored the redox balance and histomorphometric parameters to close to SHAM values in both salivary glands. Orchiectomy-induced salivary gland dysfunction was characterized by an increase in the salivary flow rate and changes in the secretion of total protein, amylase, and electrolytes, which are key factors, considered important for maintaining oral health status. To sum up, orchiectomy impaired the redox balance of the salivary glands. Our results also showed that TRT reversed the oxidative damage, morphological alterations, and salivary gland dysfunction induced by orchiectomy. Therefore, these results suggest an important action of testosterone on the redox balance and secretory ability of salivary glands.

C-reactive protein identifies patients at risk of postpancreatectomy hemorrhage

Background

Postpancreatectomy hemorrhage grade C (PPH C) is a dreaded complication after pancreaticoduodenectomy (PD) with high mortality rate. Concurrent risk factors for PPH C have been difficult to recognize. Connection between postoperative pancreatic fistulas (POPF) and PPH C is well known, but POPF is often unknown prior to the PPH. The aim of this retrospective study was to define potential predictive factors for PPH C.

Methods

Retrospectively, 517 patients who underwent PD between 2003 and 2018 were included in the study. Twenty-three patients with PPH C were identified, and a matched control group of 92 patients was randomly selected. Preoperative data (body mass index, cardiovascular disease, history of abdominal surgery, biliary stent, C-reactive protein (CRP), ASA-score), perioperative data (bleeding, pancreatic anastomosis, operation time), and postoperative data (CRP, drain amylase, POPF, biliary fistula) were analyzed as potential predictors of PPH C.

Results

High postoperative CRP (median 140 mg/L on day 5 or 6) correlated with the development of PPH C (p < 0.05). Postoperative drain amylase levels were not clinically relevant for occurrence of PPH C. Grade C POPF or biliary leak was observed in the majority of the PPH C patients, but the leaking anastomoses were not detected before the bleeding started.

Discussion

High postoperative CRP levels are related to an increased risk of PPH C.

Different Effects of Lard and Vegetable Blend Oil on Intestinal Microorganisms, Enzyme Activity and Blood Routine in Mice

The intake of moderate oils and fats is necessary to maintain the body's energy balance, and the fatty acid composition of different oils and fats varies in their nutrition and function. The study aimed to investigate the effects of lard and vegetable blend oil on gut microbiota, intestinal enzyme activities, and blood routine. Kunming mice were assigned to the three groups: (1) Control group (CK) was gavage administration with distilled water, (2) Plant oil group (ZWY) was gavage administration with edible vegetable blend oil, (3) Lard group (DWY) was gavage administration with lard. After 42 days, microbiological, digestive enzymes, and blood routine were performed. Compared with the CK group, Escherichia coli, Lactobacilli, and Bifidobacteria were significantly decreased (p < 0.05), the activities of protease, cellulase, amylase, and xylanase were markedly reduced (p < 0.05), the hemoglobin was significantly increased (p < 0.05) in the ZWY group and DWY groups, and the hematocrit was increased in the ZWY group (p < 0.05), while other routine blood indices were increased (p > 0.05). Compared to the ZWY group, the activity of cellulase and amylase were significantly increased (p < 0.05), the intestinal microorganism and the routine blood indexes had no significant difference in the DWY group. Lard and vegetable blend oil diet affected the composition of the intestinal microorganisms, and the functions of digestive enzymes. Meanwhile, the levels of digestive enzymes may be correlated with the intestinal microbiota.

IRAG2 Interacts with IP3-Receptor Types 1, 2, and 3 and Regulates Intracellular Ca2+ in Murine Pancreatic Acinar Cells

The inositol 1,4,5-triphosphate receptor-associated 2 (IRAG2) is also known as Jaw1 or lymphoid-restricted membrane protein (LRMP) and shares homology with the inositol 1,4,5-triphosphate receptor-associated cGMP kinase substrate 1 (IRAG1). IRAG1 interacts with inositol trisphosphate receptors (IP₃ receptors /IP₃R) via its coiled-coil domain and modulates Ca²⁺ release from intracellular stores. Due to the homology of IRAG1 and IRAG2, especially in its coiled-coil domain, it is possible that IRAG2 has similar interaction partners like IRAG1 and that IRAG2 also modulates intracellular Ca²⁺ signaling. In our study, we localized IRAG2 in pancreatic acinar cells of the exocrine pancreas, and we investigated the interaction of IRAG2 with IP₃ receptors and its impact on intracellular Ca²⁺ signaling and exocrine pancreatic function, like amylase secretion. We detected the interaction of IRAG2 with different subtypes of IP₃R and altered Ca²⁺ release in pancreatic acinar cells from mice lacking IRAG2. IRAG2 deficiency decreased basal levels of intracellular Ca²⁺, suggesting that IRAG2 leads to activation of IP₃R under unstimulated basal conditions. Moreover, we observed that loss of IRAG2 impacts the secretion of amylase. Our data, therefore, suggest that IRAG2 modulates intracellular Ca²⁺ signaling, which regulates exocrine pancreatic function.

Gfi1 Loss Protects against Two Models of Induced Diabetes

Background: Although several approaches have revealed much about individual factors that regulate pancreatic development, we have yet to fully understand their complicated interplay during pancreas morphogenesis. Gfi1 is transcription factor specifically expressed in pancreatic acinar cells, whose role in pancreas cells fate identity and specification is still elusive. Methods: In order to gain further insight into the function of this factor in the pancreas, we generated animals deficient for Gfi1 specifically in the pancreas. Gfi1 conditional knockout animals were phenotypically characterized by immunohistochemistry, RT-qPCR, and RNA scope. To assess the role of Gfi1 in the pathogenesis of diabetes, we challenged Gfi1-deficient mice with two models of induced hyperglycemia: long-term high-fat/high-sugar feeding and streptozotocin injections. Results: Interestingly, mutant mice did not show any obvious deleterious phenotype. However, in depth analyses demonstrated a significant decrease in pancreatic amylase expression, leading to a diminution in intestinal carbohydrates processing and thus glucose absorption. In fact, Gfi1-deficient mice were found resistant to diet-induced hyperglycemia, appearing normoglycemic even after long-term high-fat/high-sugar diet. Another feature observed in mutant acinar cells was the misexpression of ghrelin, a hormone previously suggested to exhibit anti-apoptotic effects on β-cells in vitro. Impressively, Gfi1 mutant mice were found to be resistant to the cytotoxic and diabetogenic effects of high-dose streptozotocin administrations, displaying a negligible loss of β-cells and an imperturbable normoglycemia. Conclusions: Together, these results demonstrate that Gfi1 could turn to be extremely valuable for the development of new therapies and could thus open new research avenues in the context of diabetes research.

Association among starch storage, metabolism, related genes and growth of Moso bamboo (Phyllostachys heterocycla) shoots

BACKGROUND

Both underground rhizomes/buds and above-ground Moso bamboo (Phyllostachys heterocycla) shoots/culms/branches are connected together into a close inter-connecting system in which nutrients are transported and shared among each organ. However, the starch storage and utilization mechanisms during bamboo shoot growth remain unclear. This study aimed to reveal in which organs starch was stored, how carbohydrates were transformed among each organ, and how the expression of key genes was regulated during bamboo shoot growth and developmental stages which should lay a foundation for developing new theoretical techniques for bamboo cultivation.

RESULTS

Based on changes of the NSC content, starch metabolism-related enzyme activity and gene expression from S0 to S3, we observed that starch grains were mainly elliptical in shape and proliferated through budding and constriction. Content of both soluble sugar and starch in bamboo shoot peaked at S0, in which the former decreased gradually, and the latter initially decreased and then increased as shoots grew. Starch synthesis-related enzymes (AGPase, GBSS and SBE) and starch hydrolase (α-amylase and β-amylase) activities exhibited the same dynamic change patterns as those of the starch content. From S0 to S3, the activity of starch synthesis-related enzyme and starch amylase in bamboo rhizome was significantly higher than that in bamboo shoot, while the NSC content in rhizomes was obviously lower than that in bamboo shoots. It was revealed by the comparative transcriptome analysis that the expression of starch synthesis-related enzyme-encoding genes were increased at S0, but reduced thereafter, with almost the same dynamic change tendency as the starch content and metabolism-related enzymes, especially during S0 and S1. It was revealed by the gene interaction analysis that AGPase and SBE were core genes for the starch and sucrose metabolism pathway.

CONCLUSIONS

Bamboo shoots were the main organ in which starch was stored, while bamboo rhizome should be mainly functioned as a carbohydrate transportation channel and the second carbohydrate sink. Starch metabolism-related genes were expressed at the transcriptional level during underground growth, but at the post-transcriptional level during above-ground growth. It may be possible to enhance edible bamboo shoot quality for an alternative starch source through genetic engineering.

Toxicity of Bioactive Molecule Andrographolide against Spodoptera litura Fab and Its Binding Potential with Detoxifying Enzyme Cytochrome P450

Spodoptera litura Fab. is a polyphagous pest causing damage to many agriculture crops leading to yield loss. Recurrent usage of synthetic pesticides to control this pest has resulted in resistance development. Plant-derived diterpenoid compound andrographolide was isolated from the leaves of Andrographis paniculata. It was analysed by gas chromatography-mass spectroscopy and quantified by HPLC. Nutritional indices and digestive enzymatic profile were evaluated. Third, fourth and fifth instar larvae were treated with different concentrations of andrographolide. At 3, 6 and 9 ppm-treated concentrations the larvae showed decreased RGR, RCR, ECI, ECD values with adverse increase in AD. The digestive enzymes were significantly inhibited when compared with control. Conspicuously, andrographolide showed pronounced mortality of S. litura by inhibition of enzyme secretion and intake of food. The binding ability of andrographolide with CYTP450 showed high affinity with low binding energy. Andrographolide has the potential to be exploited as a biocontrol agent against S. litura as an eco-friendly pesticide.

Safety of Irreversible Electroporation Ablation of the Pancreas

OBJECTIVES

To evaluate the safety of irreversible electroporation (IRE) on swine pancreatic tissue including its effects on peripancreatic vessels, bile ducts, and bowel.

METHODS

Eighteen Yorkshire pigs underwent IRE ablation of the pancreas successfully and without clinical complications. Contrast-enhanced computed tomography angiography and laboratory studies before the IRE ablation with follow-up computed tomography angiography, laboratory testing, and pathological examination up to 4 weeks postablation were performed.

RESULTS

In a subset of cases, anatomic peripancreatic vessel narrowing was seen by 1 week postablation, persisting at 4 weeks postablation, without apparent functional impairment of blood flow. Laboratory studies revealed elevated amylase and lipase at 24 hours post-IRE, suggestive of acute pancreatitis, which normalized by 4 weeks post-IRE. There was extensive pancreatic tissue damage 24 hours after IRE with infiltration of immune cells, which was gradually replaced by fibrotic tissue. Ductal regeneration without loss of pancreatic acinar tissue and glandular function was observed at 1 and 4 weeks postablation.

CONCLUSIONS

In our study, we demonstrated and confirmed the safety and minimal complications of IRE ablation in the pancreas and its surrounding vital structures. These results show the potential of IRE as an alternative treatment modality in patients with pancreatic cancer, especially those with locally advanced disease.

Ghee Butter from Bovine Colostrum Reduces Inflammation in the Mouse Model of Acute Pancreatitis with Potential Involvement of Free Fatty Acid Receptors

Acute pancreatitis (AP) is an inflammatory disease that causes severe tissue damage. Ghee butter from bovine colostrum (GBBC) is a clarified butter produced by heating milk fat to 40 °C and separating the precipitating protein. As colostrum mainly contains fatty acids (FAs), immunoglobulins, maternal immune cells, and cytokines, we hypothesized that it may exert anti-inflammatory effects. We investigated the effects of GBBC on experimental AP in mice. Two intraperitoneal (ip) injections of L-arginine (8%) were given 1 h apart to generate the AP murine model. After 12 h from the first L-arginine injection, mice were divided into the following experimental groups: AP mice treated with GBBC (oral gavage (po) every 12 h) and non-treated AP mice (po vehicle every 12 h). Control animals received vehicle only. At 72 h, mice were euthanized. Histopathological examination along with myeloperoxidase (MPO) and amylase/lipase activity assays were performed. In a separate set of experiments, FFAR1 and FFAR4 antagonists were used to verify the involvement of respective receptors. Administration of GBBC decreased MPO activity in the pancreas and lungs along with the microscopical severity of AP in mice. Moreover, treatment with GBBC normalized pancreatic enzyme activity. FFAR1 and FFAR4 antagonists tended to reverse the anti-inflammatory effect of GBBC in mouse AP. Our results suggest that GBBC displays anti-inflammatory effects in the mouse model of AP, with the putative involvement of FFARs. This is the first study to show the anti-inflammatory potential of a nutritional supplement derived from GBBC.

Modulatory effects of laurel-leaf cistus (Cistus laurifolius) ethanolic extract on innate immune responses and disease resistance in common carp (Cyprinus carpio)

Medicinal herbs are used for growth promotion, disease control and other health benefits in aquaculture industry. Here, we examined the effect of dietary laurel-leaf cistus (Cistus laurifolius) ethanolic extract on growth performance, digestive enzyme activity, haematological profile and nonspecific immune responses in common carp (Cyprinus carpio). In addition, resistance against Aeromonas hydrophila infection was examined. Common carp was fed diets containing 0 (Control), 0.1 (CL0.1), 0.5 (CL0.5) and 1 (CL1) g kg^-1 laurel-leaf cistus extract for 45 days. After 30 days, superoxide anion production (SAP) increased in CL0.1 and CL0.5 fish groups and at the end of the study all experimental fish groups had higher SAP compared to that of the control (P ˂ 0.05). Lysozyme activity (LA) was elevated in CL0.5 and CL1 treated groups on 30th day (P < 0.05), and this increase was only observed in C0.1 fish group at the end of study compared to control (P ˂ 0.05). Myeloperoxidase activity was significantly increased in CL0.5 and CL1 fish groups at the end of study. IL-1βgene expression was significantly increased in treated fish in a dose-depended manner. Similar results were observed for transcription of IL-6 and IL-8 (P < 0.05). Anti-inflammatory cytokines, IL-10 and TGF-β were highly up-regulated in the intestine and head kidney of CL treated fish groups compared to control (P < 0.05). At the end of experiment, significantly higher final body weight, weight gain, and specific growth rate were obtained in CL0.1 treated fish group compared to control. However, growth was negatively affected in CL1 fish group (P < 0.05). CL1 fish group had also a significantly higher FCR. Amylase activity was significantly increased in all experimental fish groups compared to control (P ˂ 0.05). Trypsin activity was decreased in CL0.1 and CL1 fish groups (P ˂ 0.05). WBC and RBC were significantly increased (P ˂ 0.05) in CL0.5 and CL1 fish groups, whereas haemoglobin, haematocrit, mean cell, mean cell haemoglobin contents were no significantly changed among control and treatment groups. Result of challenge test with A. hydrophila exhibited that survival rate in all treatment groups was significantly higher than that of control. These findings demonstrated that laurel-leaf cistus at 0.1 g kg^-1 can be a suitable candidate for growth promotion, immune system induction and infection control in fish.

Dietary bile acid supplementation reveals beneficial effects on intestinal healthy status of tongue sole (Cynoglossus semiliaevis)

The aim of this study was to investigate the effects of dietary bile acids (BAs) on intestinal healthy status of tongue sole in terms of immunity, antioxidant status, digestive ability, mucosal barrier-related genes expression and microbiota. Three experimental diets were prepared with BA levels at 0 mg/kg (CT), 300 mg/kg (BA1) and 900 mg/kg (BA2) in a commercial basal diet. Each diet was fed to three replicates with 120 fish (10.87 ± 0.32 g) in each tank. After an 8-week feeding trial, growth parameters were significantly enhanced in both BAs supplementary groups (P < 0.05), and compared with CT group, survival rate in BA2 group was significantly improved (P < 0.05). Intestinal lysozyme activity and contents of immunoglobulin M and complement 3 were significantly increased in both BAs supplementary groups (P < 0.05), suggesting an enhancement effect on the non-specific immune response. BAs inclusion also significantly improved intestinal antioxidant capabilities by increasing antioxidase activities and decreasing malondialdehyde levels. In addition, compared with CT group, intestinal digestive ability was substantially enhanced as indicated by the significantly increased lipase activity in BA2 group (P < 0.05) and significantly increased amylase activity in BA1 and BA2 groups (P < 0.05). Coincidentally, BAs inclusion significantly upregulated the relative expression of intestinal mucosal barrier-related genes (P < 0.05). Further, dietary BAs distinctly remodeled intestinal microbiota by decreased the abundance of some potential pathogenic bacteria. In conclusion, dietary BAs supplementation is an effective way to improve the intestinal healthy status of tongue sole.

Development of a novel multi-strain wheat Qu with high enzyme activities for Huangjiu fermentation

BACKGROUND

Wheat Qu has long been used as a fermentation starter to produce Huangjiu. Wheat Qu quality depends on its microbial community structure and the hydrolytic enzymes generated by the micro-organisms.

RESULTS

Strain YF1 and YF2 were successfully screened as they exhibited high acidic protease (231.9 ± 1.4 U g^-1 ) and cellulase (7.1 ± 0.6 U g^-1 ) activities. Based on a morphological and sequence analysis of the internal transcribed spacer (ITS) gene, YF1 and YF2 were identified as Rhizopus oryzae and Aspergillus niger, respectively. Cooked wheat Qu was produced using mixed fungal starter fermentations with Aspergillus oryzae SU-16, YF1, and YF2. For Qu-making, the optimized conditions for fermentation time, water content, and inoculum size were 47.8 h, 69.4%, and 6.1%, respectively. Under these conditions, compared with single-strain cooked wheat Qu, enzyme activities of amylase, acidic protease, and cellulase increased by 27.4%, 657.1%, and 1276.2%, respectively. Short peptides and free amino acids contents increased by 19.6% and 131.8%, respectively. This wheat Qu was used for Huangjiu brewing, and the alcohol content increased by approximately 14.6% because of the increased starch hydrolysis efficiency mainly attributed to its high enzyme activity.

CONCLUSION

Using mixed fungal strains as starter cultures may be an efficient strategy to improve wheat Qu quality, with great potential for application in industrial Huangjiu production. © 2021 Society of Chemical Industry.

Differential responses of salivary cortisol, amylase, and chromogranin A to academic stress

Salivary biomarkers have been widely used to help diagnose stress, anxiety, and/or depression. This study aimed to compare the responses of three commonly investigated salivary stress biomarkers that represent the hypothalamic-pituitary-adrenal activity (cortisol; sCort) and the sympathetic activity (alpha-amylase; sAA and chromogranin A; sCgA), using academic oral presentation as a model of stress. Twenty postgraduate dental students attended the seminar class as presenter and audience. The presenters' performances were evaluated by the instructors suggesting more stress than the audience. The saliva was collected two times: before attending class and after an academic presentation (for presenters) or during the class (for audience). The pulse rates (PR) were also recorded. The results showed that the levels of all three biomarkers, as well as PR, were significantly higher in the presenter group compared with the audience group; however, the changes were most prominent with sCort and sAA (99.56 ± 12.76% for sCort, 93.48 ± 41.29% for sAA, 16.86 ± 6.42% for sCgA, and 15.06 ± 3.41% for PR). When compared between pre-post presentation, the levels of sCgA were not different, while those of sCort and sAA were significantly increased. These results suggest more sensitive reactivity to academic stress of sCort and sAA compared with sCgA and that the response of sCgA did not necessarily follow sAA pattern even though both are claimed to reflect the sympathetic activity. More studies are needed to elucidate the roles of sCgA in stress.