Optimization of welan gum extraction and purification using lysozyme and alkaline protease

Welan gum, a natural polysaccharide produced by Sphingomonas sp. ATCC 31555, has attracted considerable attention in the scientific community due to its desirable properties. However, challenges, such as high viscosity, residual bacterial cells, carotenoids, and protein complexation, hinder the widespread application of welan gum. In this study, we established a method for the extraction and purification of welan gum using a synergistic approach with lysozyme and alkaline protease. Lysozyme hydrolysis conditions were optimized by applying response surface methodology, and the best results for bacterial cell removal were achieved at 11 000 U/g, 44 °C, and pH 9 after 3 h of treatment. Subsequently, we evaluated protein hydrolysis through computer simulation and identified alkaline protease as the most suitable enzyme. Through experimental investigations, we found that the optimal conditions for alkaline protease hydrolysis were 7500 U/g, 50 °C, pH 10, and 600 rpm. These conditions resulted in a sugar recovery rate of 76.1%, carotenoid removal rate of 89.5%, bacterial removal rate of 95.2%, and protein removal rate of 87.3% after 3 h of hydrolysis. The purified welan gum exhibited high transparency and purity. Structural characterization and antioxidant activity evaluation revealed that enzymatically purified welan gum has potential application prospects. Our study provides valuable insights into the optimal method for the enzymatic extraction and purification of welan gum. Such a method is conducive to the development of the multiple potential applications of welan gum. KEY POINTS: • A novel process for the synergistic purification of welan gum using lysozyme and alkaline protease was established. • In silico virtual digestion was employed to select the purification enzyme. • Welan gum with high transparency and purity was obtained.

Lipid Metabolism-Related Gene Markers Used for Prediction Prognosis, Immune Microenvironment, and Tumor Stage of Pancreatic Cancer

Recently, more and more evidence shows that lipid metabolism disorder has been observed in tumor, which impacts tumor cell proliferation, survival, invasion, metastasis, and response to the tumor microenvironment (TME) and tumor treatment. However, hitherto there has not been sufficient research to demonstrate the role of lipid metabolism in pancreatic cancer. This study contrives to get an insight into the relationship between the characteristics of lipid metabolism and pancreatic cancer. We collected samples of patients with pancreatic cancer from the Gene Expression Omnibus (GEO), the Therapeutically Applicable Research to Generate Effective Treatments (TARGET), and the International Cancer Genome Consortium (ICGC) databases. Firstly, we implemented univariate regression analysis to get prognosis-related lipid metabolism genes screened and a construction of protein-protein interaction (PPI) network ensued. Then, contingent on our screening results, we explored the molecular subtypes mediated by lipid metabolism-related genes and the correlated TME cell infiltration. Additionally, we studied the disparately expressed genes among disparate lipid metabolism subtypes and established a scoring model of lipid metabolism-related characteristics using the least absolute shrinkage and selection operator (LASSO) regression analysis. At last, we explored the relationship between the scoring model and disease prognosis, tumor stage, tumor microenvironment, and immunotherapy. Two subtypes, C1 and C2, were identified, and lipid metabolism-related genes were studied. The result indicated that the patients with subtype C2 have a significantly lower survival rate than that of the patients with subtype C1, and we found difference in abundance of different immune-infiltrating cells. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed the association of these differentially expressed genes with functions and pathways related to lipid metabolism. Finally, we established a scoring model of lipid metabolism-related characteristics based on the disparately expressed genes. The results show that our scoring model have a substantial effect on forecasting the prognosis of patients with pancreatic cancer. The lipid metabolism model is an important biomarker of pancreatic cancer. Using the model, the relationship between disease prognosis, molecular subtypes, TME cell infiltration characteristics, and immunotherapy in pancreatic cancer patients could be explored.

New Horizons in Probiotics: Unraveling the Potential of Edible Microbial Polysaccharides through In Vitro Digestion Models

In vitro digestion models, as innovative assessment tools, possess advantages such as speed, high throughput, low cost, and high repeatability. They have been widely applied to the investigation of food digestion behavior and its potential impact on health. In recent years, research on edible polysaccharides in the field of intestinal health has been increasing. However, there is still a lack of systematic reviews on the application of microbial-derived edible polysaccharides in in vitro intestinal models. This review thoroughly discusses the limitations and challenges of static and dynamic in vitro digestion experiments, while providing an in-depth introduction to several typical in vitro digestion models. In light of this, we focus on the degradability of microbial polysaccharides and oligosaccharides, with a particular emphasis on edible microbial polysaccharides typically utilized in the food industry, such as xanthan gum and gellan gum, and their potential impacts on intestinal health. Through this review, a more comprehensive understanding of the latest developments in microbial polysaccharides, regarding probiotic delivery, immobilization, and probiotic potential, is expected, thus providing an expanded and deepened perspective for their application in functional foods.

Effects of In Vitro Fermentation of Polysialic Acid and Sialic Acid on Gut Microbial Community Composition and Metabolites in Healthy Humans

The influence of polysialic acid (PSA) and sialic acid (SA) on the gut microbial community composition and metabolites in healthy humans was investigated using a bionic gastrointestinal reactor. The results indicated that PSA and SA significantly changed the gut microbiota and metabolites to different degrees. PSA can increase the relative abundances of Faecalibacterium and Allisonella, whereas SA can increase those of Bifidobacterium and Megamonas. Both can significantly increase the content of short-chain fatty acids. The results of metabolome analysis showed that PSA can upregulate ergosterol peroxide and gallic acid and downregulate the harmful metabolite N-acetylputrescine. SA can upregulate 4-pyridoxic acid and lipoic acid. PSA and SA affect gut microbiota and metabolites in different ways and have positive effects on human health. These results will provide a reference for the further development of PSA- and SA-related functional foods and health products.

Phase II clinical trial of neoadjuvant anti-PD-1 (toripalimab) combined with axitinib in resectable mucosal melanoma

BACKGROUND

The outcome of patients with resectable mucosal melanoma is poor. Toripalimab combined with axitinib has shown impressive results in metastatic mucosal melanoma with an objective response rate of 48.3% and a median progression-free survival of 7.5 months in a phase Ib trial. It was hypothesized that this combination administered in the neoadjuvant setting might induce a pathologic response in resectable mucosal melanoma, so we conducted this trial.

PATIENTS AND METHODS

This single-arm phase II trial enrolled patients with resectable mucosal melanoma. Patients received toripalimab 3 mg/kg once every 2 weeks (Q2W) plus axitinib 5 mg two times a day (b.i.d.) for 8 weeks as neoadjuvant therapy, then surgery and adjuvant toripalimab 3 mg/kg Q2W starting 2 ± 1weeks after surgery for 44 weeks. The primary endpoint was the pathologic response rate according to the International Neoadjuvant Melanoma Consortium recommendations.

RESULTS

Between August 2019 and October 2021, 29 patients were enrolled and received treatment, of whom 24 underwent resection. The median follow-up time was 34.2 months (95% confidence interval 20.4-48.0 months). The pathologic response rate was 33.3% (8/24; 4 pathological complete responses and 4 pathological partial responses). The median event-free survival for all patients was 11.1 months (95% confidence interval 5.3-16.9 months). The median overall survival was not reached. Neoadjuvant therapy was tolerable with 8 (27.5%) grade 3-4 treatment-related adverse events and no treatment-related deaths. Tissue samples of 17 patients at baseline and after surgery were collected (5 responders and 12 nonresponders). Multiplex immunohistochemistry demonstrated a significant increase in CD3+ (P = 0.0032) and CD3+CD8+ (P = 0.0038) tumor-infiltrating lymphocytes after neoadjuvant therapy, particularly in pathological responders.

CONCLUSIONS

Neoadjuvant toripalimab combined with axitinib in resectable mucosal melanoma demonstrated a promising pathologic response rate with significantly increased infiltrating CD3+ and CD3+CD8+ T cells after therapy.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Effect of monosaccharide composition and proportion on the bioactivity of polysaccharides: A review

Polysaccharides have been widely used in pharmaceutical and food industries due to their diverse bioactivity, high safety, and few or no side effects. However, inability to quickly produce, screen, and synthesize bioactive polysaccharides is the limiting factor for their development and application. Structural features determine and influence the bioactivity of polysaccharides. Among them, monosaccharide is the basic unit of polysaccharide, which not only affects electrification, functional group, and bioactivity of polysaccharide but also is one of the simplest polysaccharide indexes to be detected. At present, effects of monosaccharide composition and proportion on anti-inflammatory, antioxidant, antitumor, immunomodulatory, antibacterial, and prebiotic activities of polysaccharides are reviewed. Further problems need to be considered during regulation and analysis of monosaccharide composition and proportion of polysaccharides. Overall, present work will provide help and reference for production, development, and structure-function investigation of polysaccharides based on their monosaccharide.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Antibacterial activity of a polysaccharide isolated from Artemisia argyi leaf against Staphylococcus aureus and mechanism investigation

Abuse of antibiotics has led to excessive amounts of antibiotic residues in food and environment, thus enhancing pathogenic bacterium resistance and threatening human health. Therefore, searching and developing safe and green antibiotic alternatives are necessary. In this study, an Artemisia argyi leaf polysaccharide (AALP) fraction was extracted and analyzed. Chemical composition analysis showed that the carbohydrate, uronic acid, protein, and polyphenol content in AALP were 68.3 % ± 4.13 %, 9.4 % ± 0.86 %, 1.79 % ± 0.27 %, and 0.16 % ± 0.035 %, respectively. Chromatographic results suggested that AALP contained rhamnose, arabinose, glucosamine, galactose, glucose, xylose, mannose, galacturonic acid, and glucuronic acid in a molar ratio of 9.26, 1.35, 1.18, 3.04, 48.51, 2.33, 31.26, 3.93, and 9.08; the weight average molecular weight, number average molecular weight, and polydispersity of AALP were 5.41 kDa, 4.63 kDa, and 1.168, respectively. Fourier transform infrared spectroscopy indicated that AALP constituted the polysaccharide-specific groups of CH, CO, and OH. Meanwhile, AALP showed a dose-dependent inhibitory effect on Staphylococcus aureus in the inhibition zone assay, and the minimal inhibitory concentration was 1.25 mg/mL. Furthermore, AALP disrupted the cell wall, depolarized the inner membrane potential, and inhibited the activities of succinate dehydrogenase and malate dehydrogenase in S. aureus.

Comparison of the Time and Accuracy of Intraoral Scans Performed by Dentists, Nurses, Postgraduates, and Undergraduates

OBJECTIVE

This study aimed to assess the scanning time (ST) and accuracy of 10 repeated upper and lower dentition scans by four groups of operators with different professional backgrounds.

METHODS

There were a total of 32 participants, including dentists, nurses, postgraduates, and undergraduates (n=8). They received the same training about intraoral scanning and then performed 10 repeat scans on the plaster maxillary and mandibular dentition models in a manikin head, with the first five scans being the T1 phase and the last five scans being the T2 phase. Each ST was recorded. Trueness and precision were evaluated by root mean square (RMS) value gained from alignments of corresponding virtual models. For statistical analysis, the paired-sample t-tests, one-way ANOVA, and Pearson correlation tests were employed (α=0.05).

RESULTS

Limiting the comparison in scan phase and scan target the sequence of STs for the four groups was the same (p<0.05), by which undergraduates, postgraduates, nurses, and dentists were in descending order. Undergraduates gained the best precision, followed by postgraduates, dentists, and nurses, in both maxillary and mandibular scanning (p<0.05). Compared with corresponding items of the T1 phase, the trueness of the T2 phase was much higher (p<0.05), while the ST of the T2 phase was much shorter (p<0.05).

CONCLUSIONS

The operator's professional background affects the precision and scanning time but not the trueness. Most dental personnel have good access to the intraoral scanner. As the number of scans increased, the accuracy and scanning efficiency also improved.

Proton Therapy for Ocular Melanoma: A Dosimetric Comparison of Three Different Delivery Systems

PURPOSE/OBJECTIVE(S)

The purpose of this study is to compare the treatment plans for intraocular tumors with two types of Pencil Beam Scanning (PBS) machine configurations and compare them with the widely used uniform scanning (US)/scattering technique.

MATERIALS/METHODS

Two virtual PBS machines were constructed for ocular planning. The first machine (P1) consisted of a standard spot size and a 7.5cm WET range shifter (RS) positioned 50cm upstream from the aperture. The second machine (P2) had a smaller spot size and used a 4cm WET RS but had no aperture support. These PBS delivery systems resemble currently available models. Ten patients with different locations and sizes of intraocular tumors were planned with US using 2-3 conformal fields following our institution's intraocular criteria. PBS spot patterns for each machine were optimized using the same beam geometry as the US plan to achieve identical tumor coverage. PBS distribution was calculated using Monte Carlo. All air gaps were minimized as small as clinically achievable. PBS plans passed robustness criteria with all scenarios meeting CTV D95>95% with 2mm translational offsets and 3.5% range uncertainty.

RESULTS

The average conformity index (CI) of 95% reference isodose was better for both PBS techniques (P1: 1.43±0.22, P2:1.5±0.32) versus US (1.72±0.56) for all plans (p = 0.025, p = 0.034). The average CI of 50% reference isodose was worse for the P2 plans (10.4±3.3) compared to US (9.34±2.93). However, CI 50% for P1 plans was better than US (5.21±1.24, p<0.003). There were no significant improvements to OARs using P2. However, the mean dose to anterior structures ciliary body, lacrimal gland, and D0.03cc lens were significantly lower in the P1 plans than in the US plans (p<0.016).

CONCLUSION

Small spot size PBS systems without apertures can achieve similar coverage to US plans but have higher OAR dose. PBS systems with a standard spot size and reconfigured RS and apertures are better for anterior OAR sparing and is non-inferior to US planning of intraocular targets.

Promoting substrates uptake and curdlan synthesis of Agrobacterium sp. by attenuating the exopolysaccharide encapsulation

During curdlan production by Agrobacterium sp., the secreted exopolysaccharide (EPS) gradually encapsulated Agrobacterium sp., accompanied by cell aggregation, resulted in inhibited substrate uptake and curdlan synthesis. To relieve the EPS encapsulation effect, the shake-flask culture medium was quantitatively supplemented with 2 % to 10 % endo-β-1,3-glucanase (BGN), while obtaining curdlan with a decreased weight-average molecular weight ranging from 18.99 × 10⁴ Da to 3.20 × 10⁴ Da. In a 7-L bioreactor, the 4 % BGN supplement substantially attenuated the EPS encapsulation, resulting in increased glucose consumption and curdlan yield to 66.41 g/L and 34.53 g/L after fermentation of 108 h, which improved 43 % and 67 %, respectively compared with the control. The disruption of EPS encapsulation with BGN treatment accelerated the regeneration of ATP and UTP, resulting in sufficient uridine diphosphate glucose for curdlan synthesis. The upregulation of related genes at the transcription level reveals that the respiratory metabolic intensity, the energy regeneration efficiency, and the curdlan synthetase activity were enhanced. This study presents a simple and novel strategy of relieving the effects of EPS encapsulation on the metabolism of Agrobacterium sp. for the high-yield and value-added production of curdlan, which could be potentially applied in producing other EPSs.

A Comparative Study of the Effects of Whole Cereals and Refined Cereals on Intestinal Microbiota

Cereals are one of the most important foods on which human beings rely to sustain basic life activities and are closely related to human health. This study investigated the effects of different steamed buns on intestinal microbiota. Three steamed buns were prepared using refined flour (RF), 1:1 mixed flour (MF), and whole wheat flour (WF). In vitro digestion simulations were conducted using a bionic gastrointestinal reactor (BGR) to examine their influence on intestinal microbiota. The results showed that at 0.5% addition, butyric acid and short-chain fatty acids in WF were significantly different from those in RF and MF (p < 0.05). WF also promoted the proliferation of beneficial microbiota, such as Megamonas and Subdoligranulum. At 0.5%, 1.0%, and 1.5% additions of WF, acetic acid and short-chain fatty acids at 1.5% WF increased by 1167.5% and 11.4% from 0.5% WF, respectively, and by 20.2% and 7.6% from 1.0% WF, respectively. WF also promoted the proliferation of Bifidobacterium, Lactobacillus, and Bacteroides and inhibited the growth of pathogenic microbiota, such as Streptococcus, Enterococcus, and Klebsiella. These findings support the consumption of whole cereals and offer insights into the development of new functional foods derived from wheat.

Fusarium diversity associated with diseased cereals in China, with an updated phylogenomic assessment of the genus

Fusarium species are important cereal pathogens that cause severe production losses to major cereal crops such as maize, rice, and wheat. However, the causal agents of Fusarium diseases on cereals have not been well documented because of the difficulty in species identification and the debates surrounding generic and species concepts. In this study, we used a citizen science initiative to investigate diseased cereal crops (maize, rice, wheat) from 250 locations, covering the major cereal-growing regions in China. A total of 2 020 Fusarium strains were isolated from 315 diseased samples. Employing multi-locus phylogeny and morphological features, the above strains were identified to 43 species, including eight novel species that are described in this paper. A world checklist of cereal-associated Fusarium species is provided, with 39 and 52 new records updated for the world and China, respectively. Notably, 56 % of samples collected in this study were observed to have co-infections of more than one Fusarium species, and the detailed associations are discussed. Following Koch's postulates, 18 species were first confirmed as pathogens of maize stalk rot in this study. Furthermore, a high-confidence species tree was constructed in this study based on 1 001 homologous loci of 228 assembled genomes (40 genomes were sequenced and provided in this study), which supported the "narrow" generic concept of Fusarium (= Gibberella). This study represents one of the most comprehensive surveys of cereal Fusarium diseases to date. It significantly improves our understanding of the global diversity and distribution of cereal-associated Fusarium species, as well as largely clarifies the phylogenetic relationships within the genus. Taxonomic novelties: New species: Fusarium erosum S.L. Han, M.M. Wang & L. Cai, Fusarium fecundum S.L. Han, M.M. Wang & L. Cai, Fusarium jinanense S.L. Han, M.M. Wang & L. Cai, Fusarium mianyangense S.L. Han, M.M. Wang & L. Cai, Fusarium nothincarnatum S.L. Han, M.M. Wang & L. Cai, Fusarium planum S.L. Han, M.M. Wang & L. Cai, Fusarium sanyaense S.L. Han, M.M. Wang & L. Cai, Fusarium weifangense S.L. Han, M.M. Wang & L. Cai. Citation: Han SL, Wang MM, Ma ZY, Raza M, Zhao P, Liang JM, Gao M, Li YJ, Wang JW, Hu DM, Cai L (2023). Fusarium diversity associated with diseased cereals in China, with an updated phylogenomic assessment of the genus. Studies in Mycology 104: 87-148. doi: 10.3114/sim.2022.104.02.

Synchronous Fabrication of Custom One-piece Glass Fiber Post-and-core and Zirconia Crown by a Fully Digital Workflow

Combined crown and post-and-core treatment often requires multiple intermittent appointments and takes a long time. This article describes a novel method for simultaneously fabricating a custom glass fiber post-and-core and the corresponding crown. The critical step, defined as a post-and-core virtual try-in, is to construct a virtual crown abutment that mimics the profile of a real one gained after post-cementation and tooth preparation. The fully digital workflow optimizes the treatment and saves time by accomplishing restorations on the first visit.

[Clinical effect evaluation of immediate implant and immediate restoration with socket-shield technique in aesthetic area: a retrospective study with up to 5-year follow-up]

Objective: To evaluate the clinical effect of socket-shield technique for 5 years after immediate implantation and immediate restoration in aesthetic area. Methods: The retrospective study was conducted between July, 2013 and July, 2020. A total of 29 patients, with 34 implants, who received immediate implantation and immediate restoration with socket-shield technique in the esthetic zone in Department of Fourth Clinical Division, Peking University School and Hospital of Stomatology were included in this study. The implants survival rate, complications and the pink esthetic score (PES) were evaluated (60.2±26.7) months (13-101 months) after operation. The digital models before treatment and at the final follow-up were obtained, to measure the changes of soft tissue. The labial alveolar bone recession was measured by cone-beam CT. Results: All 34 implants survived during follow-up. The PES was (12.80±1.05), there was no significant difference in PES scores between dental positions (F=1.77, P=0.150). The gingival margin recession was (0.12±0.09) mm, and labial contour change at 2 mm apical to the gingival zenith was (0.45±0.17) mm. The labial alveolar bone recession was (0.14±0.46) mm. Conclusions: Immediate implant with socket-shield technique could maintain the gingival margin and labial alveolar bone, and preserve the soft tissue contour well to achieve good esthetic outcome.

Polymer-based graphene composite molding: a review

Polymer-based graphene composite products with high mechanical properties, heat resistance, corrosion resistance and electrical conductivity are obtained by different molding technologies. Although these processes conveniently realize the molding of polymer composites, it is often difficult to control the product quality because of the fluctuation of the temperature and pressure threshold. At the same time, a high temperature or external load will carbonize polymer composites or cause excessive porosity to influence the compacted density and electrical conductivity. In this review, additive manufacturing, injection molding, extrusion molding, hot pressing, spark plasma sintering, electromagnetic-assisted molding and other processing methods were introduced. Meanwhile, the powder molding mechanism and material constitutive model were introduced, providing appropriate molding methods and theoretical guidance based on the performance of raw materials and the performance requirements of products.

[Correlation between dyslipidemia and the risk of papillary thyroid carcinoma]

Objective: To investigate the correlation between dyslipidemia and the risk of papillary thyroid carcinoma (PTC). Methods: A case-control study was conducted. PTC patients diagnosed by pathology in Tianjin Medical University Cancer Institute and Hospital from April 2014 to August 2019 were enrolled as the experimental group, and healthy controls in the physical examination center at the same time were also enrolled as the control group. The demographic data and blood lipid parameters of the subjects were collected. Multivariate logistic analyses were used to assess the correlation between dyslipidemia and the risk of PTC. Results: A total of 2 000 cases of PTC were enrolled, with a mean age of (42±12) years, including 1 419 females (71.0%) and 581 males (29.0%). There were 4 524 cases in the control group, with a mean age of (42±9) years, including 3 311 females (73.2%) and 1 213 males (26.8%). There was no statistically difference in age and gender between the two groups (both P>0.05). Compared with the control group, triglyceride (TG) [(1.7±1.1) vs (1.4±1.0) mmol/L, P<0.001] and low-density lipoprotein (LDL) [(2.9±0.8) vs (2.8±0.7) mmol/L, P=0.015] increased in peripheral blood of PTC patients, while high-density lipoprotein (HDL) [(1.3±0.4) vs (1.4±0.3) mmol/L, P<0.001] decreased, but the difference was not statistically significant in total cholesterol (TC) [(4.9±1.0) vs (4.9±0.8) mmol/L, P=0.172]. After adjusting for age and gender, increase of TC (OR=1.20, 95%CI: 1.06-1.34, P=0.003), TG (OR=1.73, 95%CI: 1.55-1.94, P<0.001), LDL (OR=1.21, 95%CI: 1.08-1.36, P=0.001), LDL/HDL (OR=1.77, 95%CI: 1.56-2.02, P<0.001) and decrease of HDL (OR=3.15, 95%CI: 2.78-3.58, P<0.001) were the related factors of PTC. Conclusions: Compared with the control group, patients with PTC have higher level of TG and LDL and lower level of HDL. Dyslipidemia is an important factor related to the risk of PTC.

[Risk factors of recurrence or metastasis in patients with medullary thyroid carcinoma]

Objective: To analyze the risk factors of recurrence or metastasis of medullary thyroid carcinoma (MTC) and the influencing factors of disease-free survival (DFS). Methods: The clinicopathological data of MTC patients who visited Tianjin Medical University Cancer Institute and Hospital and underwent surgery from August 2014 to August 2019 were retrospectively analyzed. The patients were divided into recurrence or metastasis group and no recurrence or metastasis group. Multivariate logistic regression analysis was used to analyze the risk factors for recurrence or metastasis. Kaplan-Meier survival analysis and Cox regression analysis were used to determine the risk factors of DFS. Results: A total of 158 MTC patients were enrolled in final analysis, including 83 females and 75 males, with a median age of 52 (19-74) years. There were 146 cases of sporadic MTC (92.4%) and 12 cases of familial MTC (7.6%), respectively. Bilateral thyroid lesions presented in 33 cases (20.9%) and multiple lesions presented in 57 cases (36.1%), respectively. The median follow-up time was 59.7 (10.0-93.0) months and the median DFS was 55.5 (0-92.9) months. Presence of multifocality, the largest tumor size>2 cm, T3/4, N1b, clinical stage Ⅲ/Ⅳ, lymph node metastasis ratio (LNR)>0.3, preoperative calcitonin>2 000 ng/L, postoperative calcitonin>40 ng/L and no biochemical cure were significantly correlated with the recurrence or metastasis and DFS of MTC (all P<0.05). Clinical stage Ⅲ/Ⅳ (OR=36.57, 95%CI: 1.33-1 006.98, P=0.033), the largest tumor size>2 cm (OR=5.81, 95%CI: 1.01-33.33, P=0.049), multifocality (OR=3.64, 95%CI: 1.03-12.88, P=0.045) and postoperative calcitonin>40 ng/L (OR=15.03, 95%CI: 1.39-162.61, P=0.026) were independent risk factors of recurrence or metastasis. Clinical stage Ⅲ/Ⅳ (HR=19.39, 95%CI:1.40-268.19, P=0.027), the largest tumor size>2 cm (HR=3.64, 95%CI: 1.02-13.02, P=0.047) and postoperative calcitonin>40 ng/L (HR=10.68, 95%CI: 1.34-84.95, P=0.025) were influencing factors for DFS (all P<0.05). Conclusion: The larger tumor size, advanced clinical stage and higher postoperative calcitonin at the initial treatment of MTC are risk factors for recurrence or metastasis and influencing factors for DFS.

[Correlations of serum TgAb and TPOAb and clinicopathological features of PTC in children and adolescents]

Objective: To analyze the correlations between serum thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb) and clinicopathological features in children and adolescents with papillary thyroid carcinoma (PTC). Methods: A retrospective analysis was conduced on the clinicopathological data of children and adolescents (age≤21 years old) with PTC admitted to Tianjin Medical University Cancer Hospital from 2011 to 2019, and then, we used χ² test or Fisher's exact probability test to compare the differences in clinicopathological characteristics between groups with different TgAb and TPOAb status and multivariate logistic regression model analysis to evaluate independent predictors of cervical lymph node metastasis. Results: A total of 304 patients, including 89 males and 215 females, aged 5-21 years (median age 19 years), were enrolled in this study. The comparison between groups with different TgAb and TPOAb status showed that there were significant differences in gender, preoperative thyroglobulin (Tg) level, primary tumor location, number of primary tumors and maximum tumor diameter (all P<0.05), which suggested that TgAb⁺group (n=81) and TPOAb⁺group (n=84) had relatively better primary tumor characteristics. Patitents with TgAb⁺and TPOAb⁺were more common in females and their preoperative Tg level was mostly within the normal range, and there were significant differences in primary tumor location, number of primary tumors and maximum tumor diameter between TgAb⁺and TgAb^-(223 cases) groups (all P<0.05). There was significant difference in the maximum tumor diameter between TPOAb⁺and TPOAb^-(220 cases) groups (P<0.05). Analysis of risk factors for cervical lymph node metastasis showed that independent risk factors for central lymph node metastasis were maximum tumor diameter>2 cm (OR=2.84, 95%CI: 1.59-5.07, P<0.001) and extra-thyroid extension (OR=0.32, 95%CI: 0.17-0.60, P<0.001), and independent risk factors for lateral neck lymph node metastasis included age≤14 years old (OR=0.34, 95%CI: 0.18-0.67, P=0.002), preoperative Tg⁺(OR=2.16, 95%CI: 1.10-4.24, P=0.026) and maximum tumor diameter>2 cm (OR=3.99, 95%CI: 2.33-6.82, P<0.001). Conclusion: It is recommended to test routinely serum TgAb and TPOAb before surgery in children and adolescents with PTC. Preoperative Tg⁺, age≤14 years, maximum tumor diameter>2 cm, and extra-thyroid extension are risk factors for cervical lymph node metastasis.

Encapsulation of polyphenols in pH-responsive micelles self-assembled from octenyl-succinylated curdlan oligosaccharide and its effect on the gut microbiota

An amphiphilic polymer based on octenyl succinic anhydride-modified curdlan oligosaccharide (MCOS) was synthesized. The critical micelle concentration of MCOS was 3.91 μg·mL-1. MCOS could self-assemble into spherical micelles with a particle size of 230.1 nm and a zeta potential of - 37.9 mV. When used for polyphenol encapsulation, the loading capacity of curcumin and quercetin-co-encapsulated micelles was higher than that of single-polyphenol encapsulated micelles. In vitro gastrointestinal release test showed that the MCOS micelle presented a pH-dependent release, released a little polyphenol in simulated gastric fluid, but presented sustained release in the simulated intestinal fluid. The gastrointestinal-digested polyphenol-loaded micelles exhibited excellent antioxidant ability. In vitro human fecal fermentation indicated that the MCOS carrier could promote the production of short-chain fatty acids by gut microbiota and exhibited the highest relative abundance of Megamonas. In addition, the supplementation of curcumin and quercetin-co-loaded MCOS micelles increased the relative abundance of Bifidobacterium and inhibited the growth of Escherichia_Shigella. These findings indicated that the MCOS carrier can be potentially used for the colon-targeted delivery of hydrophobic polyphenols due to its pH-responsive property.

Fabrication of a smart drug delivery system based on hollow Ag2S@mSiO2 nanoparticles for fluorescence-guided synergistic photothermal chemotherapy

A novel near-infrared (NIR) light-triggered smart nanoplatform has been developed for cancer targeting and imaging-guided combined photothermal-chemo treatment. Notably, Ag₂S has a dual function of photothermal therapy and fluorescence imaging, which greatly simplifies the structure of the system. It can emit fluorescence at 820 nm under an excitation wavelength of 560 nm. The phase-change molecule of 1-tetradecanol (TD) is introduced as a temperature-sensitive gatekeeper to provide the nanocarrier with controlled release capability of doxorubicin (DOX). The nanocarrier (HAg₂S@mSiO₂-TD/DOX) shows a high drug loading capacity of 26.3% and exhibits an apparent NIR-responsive DOX release property. Under NIR irradiation, the photothermal effect of HAg₂S nanocores facilitated the release of DOX through the melting of TD. The cytotoxicity test shows that the nanocarriers have good biocompatibility. As the same time, the synergistic combination leads to a better cancer inhibition effect than individual therapy alone in vitro. Cell uptake tests indicate that the carriers have excellent fluorescence imaging ability and high cellular uptake for HepG2 cells. This work provides a new strategy for the fabrication of smart nanocarriers with simple structures for fluorescence-mediated combination cancer therapy. Fabrication of a smart drug delivery system based on hollow Ag₂S@mSiO₂ nanoparticles for fluorescence-guided synergistic photothermal chemotherapy.

Video-assisted superior mediastinal lymphadenectomy for papillary thyroid cancer: a case report

Superior mediastinal lymph node metastases in papillary thyroid cancer are uncommon. The clinical characteristics and surgical strategy of superior mediastinal lymph node metastases remain unclear. Superior mediastinal lymphadenectomy can be accomplished either by a transcervical or transsternal approach. Transsternal approach for superior mediastinal lymphadenectomy can cause great damage; transcervical approach sometimes results in inadequate exposure. Here we report our experience of a papillary thyroid cancer patient with superior mediastinal lymph node metastases who underwent video-assisted superior mediastinal lymphadenectomy. A 49-year-old woman diagnosed with papillary thyroid cancer in left thyroid underwent unilateral lobectomy and ipsilateral central and lateral node dissection in the local hospital 4 years ago. Currently lymph node metastases were found in mediastinum and the right neck, some of which were adjacent to the right innominate vein. Unilateral lobectomy, ipsilateral central and lateral node dissection, and video-assisted superior mediastinal lymphadenectomy were successfully performed by transcervical approach. Subsequently, the patient received thyroxine suppression therapy and adjuvant radioiodine treatment. Video-assisted superior mediastinal lymphadenectomy, providing adequate exposure for a complete superior mediastinal lymphadenectomy, is proved to be safe and feasible.

Antioxidant and anti-inflammatory properties of an aminoglycan-rich exopolysaccharide from the submerged fermentation of Bacillus thuringiensis

Proteins from Bacillus thuringiensis are widely used as biopesticides but little is known about its exopolysaccharides. The exopolysaccharide BPS-2 was extracted from B. thuringiensis IX-01 after high-cell-density fermentation. BPS-2 is a heteropolysaccharide (molecular weight 29.36 kDa) composed of D-galactosamine, arabinose, glucosamine, glucose, and mannose in molar ratios 5.53: 1.77:4.74:3.24:1. In vitro upper gastrointestinal simulations showed that BPS-2 has strong anti-digestive capacity, with scavenging of DPPH, hydroxyl, ABTS, and superoxide anions radicals of 31.34 ± 1.67 %, 32.43 ± 3.01 %, 34.31 ± 2.12 %, and 48.53 ± 3.55 %, respectively, after BPS-2 entered the colon. It significantly inhibited production of lipopolysaccharide-induced nitric oxide and multiple pro-inflammatory cytokines and had proliferative effects on RAW 264.7 cells. BPS-2 inhibited malondialdehyde secretion and elevated activities of glutathione peroxidase, superoxide dismutase, and total antioxidants, significantly improving the antioxidant status of inflammation model cells. This first report of the in vitro anti-inflammation and antioxidant properties of BPS-2 from B. thuringiensis provides a basis for biopharmaceutical applications.

Emulsifying properties and bioavailability of clove essential oil Pickering emulsions stabilized by octadecylaminated carboxymethyl curdlan

In the present study, clove essential oil (CEO) Pickering emulsions were stabilized by octadecylamine-modified carboxymethyl curdlan (CMCD-ODA) at different pH values. The droplet size and negatively charged zeta potential of the CMCD-ODA emulsions decreased as the pH increased from 3.0 to 11.0. Rheology results indicated that the CMCD-ODA polymer/emulsion prepared at pH 5.0 showed higher apparent viscosity and viscoelasticity than other pH conditions, which might prevent droplets from flocculating. The Pickering emulsions obtained at pH 5.0 were spherical droplets with a uniform size distribution and a mean diameter of 9.54 μm, and they exhibited excellent stability during 28 days of storage. The morphological structures of the emulsions investigated by confocal laser scanning microscopy and scanning electron microscopy indicated that the CMCD-ODA Pickering emulsion obtained at pH 5.0 was stabilized by loading amphiphilic CMCD-ODA polymer around the spherical oil droplets and forming a weak gel network structure. The CEO-loaded CMCD-ODA emulsions had higher antioxidant capacity than free CEO after 28 days of storage at pH 5.0. Given the good emulsion stability, antioxidant activity, and great antibacterial effect, the CEO-loaded carboxymethyl curdlan Pickering emulsion has promising applications in food, cosmetic, and biomedicine industries.

[Isobavachalcone induces cell death through multiple pathways in human breast cancer MCF-7 cells]

OBJECTIVE

To explore the effects of isobavachalcone (IBC) on cell death of human breast cancer MCF-7 cells and explore the possible mechanism.

METHODS

MCF-7 cells were treated with different concentrations of IBC, and the changes in cell proliferation were assessed using MTT assay. Apoptosis of MCF-7 cells following treatment with 10, 20, and 40 μmol/L IBC was analyzed using flow cytometry with annexin V-FITC/PI double staining and fluorescence microscopy, and the expressions of apoptosis- and autophagy-related proteins (Bax, Bcl-2, Akt, p-Akt, p62, and LC3) were detected with Western blotting. Electron microscopy was used to observe the changes in submicrostructure of the cells following treatment with 40 μmol/L IBC. JC-1 assay kit, ATP assay kit, and reactive oxygen species (ROS) kit were used to determine the effect of IBC on mitochondrial function of the cells.

RESULTS

MTT assay showed that IBC significantly inhibited the proliferation of MCF-7 cells in a concentration- and time-dependent manner, with IC₅₀ values of 38.46, 31.31, and 28.26 μmol/L at 24, 48, and 72 h, respectively. IBC also concentration-dependently induced apoptosis of MCF-7 cells. IBC-induced cell death was inhibited by z-VAD-fmk, a caspase inhibitor (P < 0.05), but not by the necroptosis inhibitor necrostatin-1 (Nec-1). Western blotting showed that IBC-induced MCF-7 cell apoptosis by increasing Bax expression and down-regulating the expressions of Bcl-2, Akt and p-Akt-473 (all P < 0.05). With the increase of IBC concentration, the expression of autophagy-related protein p62 and the LC3-II/I ratio increased progressively. Electron microscopy revealed the presence of autophagic bodies in IBC-treated MCF-7 cells. IBC treatment also resulted in decreased mitochondrial membrane potential and intracellular ATP level and increased ROS accumulation in MCF-7 cells (P < 0.05).

CONCLUSION

IBC is capable of inducing both apoptosis and autophagy in MCF-7 cells, suggesting the potential value of IBC as a lead compound in the development of anti-breast cancer agents.

Efficient precious metal Rh(III) adsorption by waste P. pastoris and P. pastoris surface display from high-density culture

Rhodium is one of the most used precious metals in catalysis both in laboratory reactions and industrial processes. However, the adsorption of Rh(III) by microorganisms has been seldomly reported. In this work, waste P. pastoris and recombinant P. pastoris with surface-displayed Rh metal peptides (P. pastoris GS-R) from high-density culture were used as novel adsorbents to study Rh(III) adsorption. Under the optimal adsorption conditions of biomass of 0.25 g L^-1, pH of 1.2, temperature of 30 °C, and adsorption time of 2 h in simulated wastewater, the maximum adsorption ratios of 55.69% (110.1 mg g^-1) and 75.03% (142.11 mg g^-1) were achieved for waste P. pastoris and P. pastoris GS-R, respectively. Using the two adsorbents, the adsorption kinetic models fit the quasi-second-order equation, and isotherm models followed the Langmuir and Temkin equations, respectively. P. pastoris GS-R showed high adsorption capacity (48.49%) and selectivity (65.86%) in electroplating wastewater, and the desorption ratio reached 34.49% after treatment with 2 M HNO₃ and ultrasonic wave. Therefore, an environmental-friendly strategy was developed for the recovery of Rh(III) and other precious metals by using P. pastoris.

Absorption and Conversion of SO2 in Functional Ionic Liquids: Effect of Water on the Claus Reaction

The absorption of SO₂ from flue gas and its conversion to chemicals is important in the industry. Functional ionic liquids (ILs) have been broadly used to absorb SO₂ in flue gas, but seldom convert it to chemicals. As we know, water is inevitable in a desulfurization process. In this work, three functional ILs (monoethanolaminium lactate-[MEA][Lac], 1,1,3,3-tetramethylguanidinium lactate-[TMG][Lac], tetraethylammonium lactate-[N₂₂₂₂][Lac]) with or without water were used as absorbents to absorb SO₂ in flue gas, and then the absorbed SO₂ in the absorbents was converted to sulfur via a Claus reaction. The result shows that the three ILs can efficiently absorb SO₂ and convert it to sulfur. But the addition of water in the ILs can reduce the conversion of absorbed SO₂, and the conversion increases with increasing the acidity of absorbents. To explain this phenomenon, we studied the Claus reaction in H₂SO₃, NaHSO₃ and Na₂SO₃ aqueous solutions. It turns out that the conversion of the Claus reaction is related to the species of S (IV) in the order of the oxidability: H₂SO₃ > HSO₃ ^- > SO₃ ^2-, and their proportions dependent on the pH of solutions. On the basis of the absorption mechanism of SO₂ in functional ILs aqueous solution, H₂S reacts with HSO₃ ^- and SO₃ ^2- with weaker oxidability, resulting in the lower conversion. Importantly, we found that the addition of lactic acid could increase the conversion of SO₂ via the Claus reaction.

Production of prebiotic gellan oligosaccharides based on the irradiation treatment and acid hydrolysis of gellan gum

Biologically active gellan oligosaccharides (GOSs), newly found plant elicitors and biostimulants, are produced from the hydrolysis of gellan gum. Traditional hydrolysis with concentrated acid suffers from the problems of high pollution and low functional oligosaccharide yield because the process is difficult to control. Irradiation (⁶⁰Co γ-ray) with a dosage ranging from 0 kGy to 175 kGy was used to degrade gellan gum efficiently and cleanly into low molecular weight (M_w) gellan with an average M_w ranging from 449,119 Da to 72,903 Da. The low M_w gellan irradiated at 70 kGy was further hydrolyzed with low concentration acid (0.5 mol/L HCl) to produce GOSs with DPs mainly 4 and 8, indicating that the Rha-β-(1 → 3)-Glc bonds in gellan gum were easily cut to produce residues with tetrasaccharide repeat subunits. Besides antioxidant activity, GOSs were also proved with prebiotic activity by in vitro fecal fermentation in a self-designed bionic intestinal reactor.

Exopolysaccharide synthesis repressor genes (exoR and exoX) related to curdlan biosynthesis by Agrobacterium sp

Curdlan is a neutral, water-insoluble, unbranched, linear β-(1,3)-glucan. This study explored the roles of exoR and exoX in curdlan biosynthesis in Agrobacterium sp. ATCC 31749. The microcapsule biosynthesis of ΔexoR strain was reduced, and the motility of this strain increased remarkably compared with the wild-type (WT) strain during the cell growth phase. The curdlan yields of ΔexoR and ΔexoX strains enhanced by 19% and 17%, and the glucose utilization increased by 12% and 11%, respectively, compared with the WT strain during batch fermentation. By contrast, the curdlan yields of exoR and exoX overexpression strains decreased by 28% and 33%, respectively. The gel strength produced by ΔexoR and exoX overexpression strains decreased compared with the WT strain. RT-qPCR analysis at the transcriptional level revealed that key genes in exopolysaccharide synthesis and central metabolic pathways were up-regulated in ΔexoX and ΔexoR strains during gel production. Metabolomics analysis of ΔexoR and ΔexoX mutants proved the rates of central metabolic and electron transport chain were accelerated.

Food-Grade Expression of Manganese Peroxidases in Recombinant Kluyveromyces lactis and Degradation of Aflatoxin B1 Using Fermentation Supernatants

Aflatoxins are naturally occurring high-toxic secondary metabolites, which cause worldwide environmental contaminations and wastes of food and feed resources and severely threaten human health. Thus, the highly efficient methods and technologies for detoxification of aflatoxins are urgently needed in a long term. In this work, we report the construction of recombinant Kluyveromyces lactis strains GG799(pKLAC1-Phsmnp), GG799(pKLAC1-Plomnp), GG799(pKLAC1-Phcmnp), and then the food-grade expression of the three manganese peroxidases in these strains, followed by the degradation of aflatoxin B₁ (AFB₁) using the fermentation supernatants. The expression of the manganese peroxidases was achieved in a food-grade manner since Kluyveromyces lactis is food-safe and suitable for application in food or feed industries. The inducible expression process of the optimal recombinant strain GG799(pKLAC1-Phcmnp) and the aflatoxin B₁ degradation process were both optimized in detail. After optimization, the degradation ratio reached 75.71%, which was an increase of 49.86% compared to the unoptimized results. The degradation product was analyzed and determined to be AFB₁-8,9-dihydrodiol. The recombinant strain GG799(pKLAC1-Phcmnp) supernatants degraded more than 90% of AFB₁ in the peanut samples after twice treatments. The structural computational analysis for further mutagenesis of the enzyme PhcMnp was also conducted in this work. The food-grade recombinant yeast strain and the enzyme PhcMnp have potential to be applied in food or feed industries.

Evidence of a shared binding site for Bacillus thuringiensis Cry1Ac and Cry2Aa toxins in Cnaphalocrocis medinalis cadherin

Insect midgut cadherins function as receptors and play critical roles as protein receptors of insecticidal Bacillus thuringiensis (Bt) toxins used as biopesticides and in Bt transgenic crops worldwide. Here, we cloned and characterized the full-length midgut cadherin (CmCad) cDNA from the rice leaffolder (Cnaphalocrocis medinalis), a destructive pest of rice in many Asian countries. Expression of recombinant proteins corresponding to the extracellular domain of CmCad allowed testing binding of Cry proteins. Results from in vitro ligand blotting and enzyme-linked immunosorbent assays supported that the extracellular domain of CmCad contains regions recognized by both Cry1Ac and Cry2Aa. Molecular modelling and docking simulations indicated that binding to both Cry1Ac and Cry2Aa is localized primarily within a CmCad motif corresponding to residues T1417-D1435. A recombinant CmCad protein produced without residues T1417-D1435 lacked binding to Cry1Ac and Cry2Aa, confirmed our modelling predictions that CmCad has a shared Cry1Ac and Cry2Aa binding site. The potential existence of a shared binding region in CmCad suggests that caution should be taken when using combinations of Cry1Ac and Cry2Aa in pyramided transgenic rice, as their combined use could speed the evolution of resistance to both toxins.

Analysis of microbial diversity in the root of Astragalus mongholicus

Abstract The dry root of Astragalus mongholicus has therapeutic effects such as tonifing the middle - jiao, replenishing qi, solidifing the surface, promoting diuresis, dispelling sepsis outwards and nourishing muscle. There are some slices having black spots after slicing the root of astragalus. The diversity of endophytic fungi between slices with black spots and normal slices was analysed in this paper. The endophytic fungal sequences obtained by high-throughput sequencing were 298,044 and 297,396, and the 116 OTU subsets obtained after clustering belonged to 3 phyla, 9 classes, 22 orders, 38 families and 46 genera. The dominant classes were Eurotiomycetes and Leotiomycetes. The dominant order is Eurotiales and Helotiales. The dominant families are Helotiales_fam_Incertae_sedis and Aspergillaceae. The dominant genera are Cadophora and Aspergillus. There are some peculiar fungal flora in both normal slices and spotted slices. The study on endophytic fungi diversity of astragalus slices will provide some help for drug development of this plant.