Assessing Starch Retrogradation from the Perspective of Particle Order.

Starch retrogradation is a complex process involving changes in the multi-scale structure. In particular, the particle order of retrograded starch is unclear. In this study, we measured the radius of gyration (Rg) and radius of particles (R) of retrograded starch using small-angle X-ray scattering. Retrograded starch included various Rg, and the values of Rg depended on the length and state of the starch chains. With time, the standard deviations of R decreased due to the increase in particle uniformity. Based on these results, a new method for assessing the degree of starch retrogradation was established from the perspective of the particle order. The accuracy of the new method was verified through differential scanning calorimetry and scanning electron microscopy. The microstructures of the samples indicated that the retrograded starch granules contained substructures (primary particles) of different sizes. This study provides a new perspective for analyzing the structure of retrograded starch.

Improvement of resistant starch content and thermal-stability of starch-linoleic acid complex: An attempt application in extruded recombinant rice.

The utilization of resistant starch in food industry is restricted due to its susceptibility to thermal degradation. This work aimed to address this issue by preparing a starch-linoleic acid complex (RS5) via extrusion method combined with heat moisture treatment, obtaining VII-type crystal (melting temperature âˆ¼110 °C). The complex obtained through an 8-hour heat moisture treatment exhibited a high RS content of 46.7 %. The glycemic index (pGI) values predicted by two different methods for this complex were 54.5 and 64.2. The complex was further processed into recombinant rice, which exhibited similar textural properties to commercial rice products after cooking. Notably, the recombinant rice maintained an anti-enzyme structure (VII-type complex) as evidenced by its significant resistant starch content of 38.1 %, the lowest pGI values of 59.6 and 72.5. These findings could serve as a useful reference to aid in developing low glycemic index foods based on starch.

Structural properties of the intra- and interhelical cavities of V6-type crystalline starches.

V-type crystalline starch is known for its property to enhance aroma retention. Intra- and interhelical cavities are the first-order characteristics of V-type crystalline starch, which can affect its properties from microscopic level. This work aims to provide a detailed analysis of structural attributes of intra- and interhelical cavities and their influence on the properties of V-type crystalline starches. Helix deformation was caused due to the formation of interhelical cavities, which was reflected by the downfield shift of the signals for C1 and C4 as well as the appearance of an independent signal for C3 in 13C CP/MAS NMR spectra. Unit cell and lamellar structure formed by the aggregation of intrahelical cavities exhibited relatively low cell volume and high fractal dimension at crystal cell and lamellar levels. Toward a larger crystal, d-spacing increased with the formation of interhelical cavities, causing low-angle shifts of V-type crystalline starches in X-ray diffraction profiles. Intrahelical cavities enabled V6I-type crystalline starch to show high crystallinity per unit volume and a favorable short-range order, contributing greatly to the stable thermal properties. The flavor quality improvement in starch-based food is attributed to the structural characteristics of helical cavities and their relationship with the properties of V-type crystalline starches.

Organocatalytic allylic alkylation of alkyne-substituted MBH carbonates: access to quaternary carbon-containing 1,4-enynes.

A DABCO-catalyzed allylic alkylation of tertiary propargylic alcohol-derived MBH carbonates with nitromethane was developed. A series of substituted 1,4-enynes with an all-carbon quaternary stereocenter were efficiently obtained in moderate to high yields. The synthetic utility of the product was demonstrated by facile synthesis of 1,4-enyne-embedded 2-pyrrolidinones.

Identification and functional characterization of Interleukin-11 in goldfish (Carassius auratus L.).

Interleukin-11 (IL-11) is a versatile cytokine that modulates cellular differentiation and proliferation in various cell types and tissues. In this study, IL-11 gene from goldfish (Carassius auratus L.) has been identified and characterized. Goldfish IL-11 (gfIL-11) has an open reading frame (ORF) that spans 591 base pairs (bp). The ORF encodes a precursor protein consisting of 196 amino acids (aa), which includes a 26 aa signal peptide and a conserved domain belonging to the IL-11 superfamily. Based on phylogenetic analysis, gfIL-11 was found to be closely related to other IL-11 homologues identified in various fish species. The gfIL-11 transcript exhibited varied expression levels across all the analyzed tissues, with the highest expression observed in the gill and spleen. Treatment of goldfish head kidney leukocytes (HKLs) with LPS and live Aeromonas hydrophila, increased gfIL-11 mRNA expression level. Recombinant gfIL-11 protein (rgIL-11) induced a dose-dependent production of TNF-α and IFNγ from goldfish HKLs. Furthermore, the administration of rgIL-11 to goldfish HKLs triggered an increase in the expression of various transcription factors such as MafB, cJun, GATA2, and Egr1, which play a vital role in the differentiation of myeloid precursors into macrophages and monocytes. Our findings provide evidence that IL-11 is a crucial cytokine that promotes cell proliferation, immune response, and differentiation across various hematopoietic lineages and stages of goldfish.

Monitoring the ecological restoration effect of land reclamation in open-pit coal mining areas: An exploration of a fusion method based on ZhuHai-1 and Landsat 8 data.

Land reclamation is a long-term, dynamic process; postreclamation monitoring and management are particularly important, and the use of remote sensing technology is a good way to conduct ecological quality monitoring and evaluations. In this study, we fused ZhuHai-1 and Landsat 8 data; selected the best band combinations to calculate ecological quality indicators such as the inverted red-edge chlorophyll index, modified soil moisture monitoring index, normalized difference built-up and soil index and land surface temperature; and constructed the fusion remote sensing ecological index to monitor the ecological restoration effect of the reclaimed area in Pingshuo, China. The results showed that the inverted red-edge chlorophyll index and modified soil moisture monitoring index had positive contributions, the normalized difference built-up and soil index had a low impact on the ecological quality of the study area, and the land surface temperature had a negative effect on ecological quality. The environment of the reclaimed area was better than that of the surrounding areas where these areas were affected by mining. The mean value of the fusion remote sensing ecological index showed a trend of "rising first, then falling" with increasing reclamation time. The ecological quality of the reclaimed area was best in areas with 20-22 years of reclamation time. The ecological condition of the area has been declining for 25 years or more of reclamation, so it is suitable to apply artificial intervention to ensure good ecological quality. The use of remote sensing technology for monitoring the effects of ecological restoration can provide a reference basis for the targeted and accurate implementation of land reclamation management measures.

Transcriptome analysis of Cryptocaryon irritans tomont responding to Bacillus licheniformis treatment.

Cryptocaryon irritans is a ciliated obligate parasite that causes cryptocaryonosis (white spot disease) and poses great threat to marine fish farming. In recent years, the use of probiotics protects fish from pathogens, which has been identified as the sustainable and environmentally friendly tool to maintain the health and well-being of the host. Accordingly, Cryptocaryon irritans tomont and probiotic Bacillus strain (B.licheniformis, previously isolated from aquaculture water) were co-cultured to detect whether B. licheniformis has anti-C. irritants effect. The result showed that during 4-day incubation, B. licheniformi with 1 × 107 CFU/mL and 1 × 108 CFU/mL concentration effectively inhibited the incubation of C. irritans tomont, indicating that B. licheniformi could inhibit the transformation from reproductive tomont to infective theront of C. irritans. Later, C. irritans samples in the control (without B. licheniformi supplementation) and 1 × 107 CFU/mL B. licheniformi treatment group were sent for transcriptome analysis. Compare with the control group, a total of 3237 differentially expressed genes were identified, among which 626 genes were up-regulated and 2611 genes were down-regulated in 1 × 107 CFU/mL B. licheniformi group. Further Kyoto Encyclopedia of Genes and Genomes pathways analysis showed that anti-C. irritans mechanism of B. licheniformi was mainly involved in the energy metabolism (carbon metabolism, oxidative phosphorylation, biosynthesis of amino acids), transcription and translation (Ribosomes, spliceosomes, RNA transport, etc), lysosome-based degradation (lysosome, phagosome, protein processing in endoplasmic reticulum) and PI3K-Akt pathways. Our study findings raised the possibility of using marine microorganism B. licheniformi in handling aquaculture associated pathogen C. irritans, and preliminarily clarified the molecular mechanism.

Structural changes of thermally treated starch during digestion and the impact on postprandial glucose homeostasis.

Intake of foods upon thermal treatment is typically associated with an elevated postprandial glycemic response, which is one of the risk factors for type 2 diabetes development and progression. In this study, rice starch was thermally treated using aqueous phase (boil), air phase (bake), and lipid phase (fry). Peak blood glucose levels in C57 mice increased by 16.94 %, 12.60 %, and 8.1 % after ingestion of thermally treated starch (20.23, 19.48, and 18.70 mmol/L), compared with raw starch (17.30 mmol/L). The insulin response to the intake of thermally treated starch increased (4.73 %-6.83 % higher than the control), whereas the concentration of GLP-1, a hormone used to promote insulin secretion, decreased (1.54 %-8.56 % lower than the control). Furthermore, thermally treated starch accelerated food absorption by enhancing gastrointestinal digestion, exacerbating postprandial glucose fluctuation at the next meal. Structural characterization showed thermal treatment reduced starch branching density and degree of structure order, which were not conducive to preventing the attack of enzymes. During digestion, they were highly hydrolyzed into low-molecular-weight fragments, and the proportion of ultrashort chains substantially increased. These findings provide a better understanding of the fine structure of starch that promotes hypoglycemia and initially explain how diets high in thermally treated starch impair glucose balance.

Transcriptome profiling and differential expression analysis of altered immune-related genes in goldfish (Carassius auratus) infected with Aeromonas hydrophila.

Goldfish (Carassius auratus) have been employed as a model organism to investigate the innate immune system and host-pathogen interactions. A Gram-negative bacterium called Aeromonas hydrophila has been found to cause mass mortality due to infection in a wide variety of fish species in the aquatic system. In this study, damages in Bowman's capsule, inflammatory tubular (proximal and distilled convoluted) structure, and glomerular necrosis were observed in A. hydrophila-infected head kidney of goldfish. To increase the better understanding of immune mechanisms of host defense against A. hydrophila, we performed a transcriptome analysis in head kidney of goldfish at 3 and 7 days of post-infection (dpi). Comparing to the control group, 4638 and 2580 differentially expressed genes (DEGs) were observed at 3 and 7 dpi, respectively. The DEGs were subsequently enriched in multiple immune-related pathways including Protein processing in endoplasmic reticulum, Insulin signaling pathway, and NOD-like receptor signaling pathway. The expression profile of immune-related genes such as TRAIL, CCL19, VDJ recombination-activating protein 1-like, Rag-1, and STING was validated by qRT-PCR. Furthermore, the levels of immune-related enzyme (LZM, AKP, SOD, and CAT) activities were examined at 3 and 7 dpi. The knowledge gained from the current study will be helpful for better understanding of early immune response in goldfish after A. hydrophila challenge, which will aid in future research on prevention strategies in teleost.

Simultaneous improvement of the physical and biological properties of starch films by incorporating steviol glycoside-based solid dispersion.

Bioactive compounds are frequently incorporated into polysaccharides (e.g., starch) to form active biodegradable films for food packaging, but some of them are water insoluble (e.g., curcumin, CUR) that will make the films have undesirable performance. Herein, CUR was successfully solubilized into the aqueous starch film solution by steviol glycoside (STE, a natural sweetener)-based solid dispersion. The mechanisms of solubilization and film formation were explored through molecular dynamic simulation and various characterization methods. The results showed that the amorphous state of CUR combined with micellar encapsulation of STE achieved the solubilization of CUR. STE and starch chains cooperated to form the film via hydrogen bonding, while CUR was uniformly and densely distributed within the film in the form of needle-like microcrystals. The as-prepared film exhibited high flexibility, great moisture barrier, and excellent UV barrier (UV transmittance: ∼0 %). Compared with the film containing CUR alone, the as-prepared film possessed higher release efficiency, antibacterial activity, and pH response sensitivity due to the assistance of STE. Hence, the introduction of STE-based solid dispersion can simultaneously improve the biological and physical properties of starch films, which provides a green, nontoxic, and facile strategy for the perfect integration of hydrophobic bioactive compounds and polysaccharide-based films.

Characterization of the pro-inflammatory roles of the goldfish (Carassius auratus L.) M17 protein.

The interleukin-6 family of cytokines possesses a diversity of roles with significant redundancy. The roles of these molecules have been relatively well characterized in mammals, with limited attention in other species. Progress has been made in the discovery of homologous molecules in fish. Here we report the characterization of pro-inflammatory properties of recombinant goldfish M17. Recombinant goldfish M17 enhanced phagocytosis, primed production of reactive oxygen intermediates, and was chemotactic to macrophages. Treatment of goldfish macrophages with LPS, heat-killed and live Aeromonas hydrophila resulted in higher M17 mRNA levels. Recombinant M17 (RgM17) induced dose-dependent production of IFNγ and IL-1ß1 in goldfish macrophages. Furthermore, treatment of macrophages with rgM17 resulted in upregulation of transcription factors that were important in the differentiation of myeloid progenitors into monocytes/macrophages (Runx1 and GATA2). Our results indicate that goldfish M17 is an essential inflammatory cytokine for proliferation and differentiation of goldfish progenitor cells.

The Fluorescence Response of Four Crystalline Starches According to Ultrasound-Assisted Starch-Salicylic Acid Inclusions.

Fluorescence has shown its superior performance in the fields of starch physicochemical properties, starch-based materials, and the interactions of starch with small molecules. However, it has not been well explored in the fluorescence characteristics of starch. Herein, the fluorescence properties of four crystalline starches (A-type tapioca starch, B-type potato starch, C-type pea starch, and V-type starch, prepared with corn starch and stearic acid) were investigated using salicylic acid (SA) as an indicator. The results of inverted fluorescence microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis indicated that SA could be included by starch. X-ray diffraction analysis further demonstrated that the inclusion of SA did not change the crystalline of the four crystal types of starches, which could provide a prerequisite for comparing the different fluorescence properties of the four crystal types of starches. Fluorescence enhancements of the four inclusions were 264.5 (B-type), 206 (C-type), 51.2 (V-type), and 28 (A-type). These results provide new insights for analyzing the fluorescence response of starch.

Construction of TiO2/starch nanocomposite cryogel for ethylene removal and banana preservation.

Perishability caused by natural plant hormone ethylene has attracted great attention in the field of fruit and vegetable (F&V) preservation. Various physical and chemical methods have been applied to remove ethylene, but the eco-unfriendliness and toxicity of these methods limit their application. Herein, a novel starch-based ethylene scavenger was developed by introducing TiO2 nanoparticles into starch cryogel and applying ultrasonic treatment to further improve ethylene removal efficiency. As a porous carrier, the pore wall of cryogel provided dispersion space, which increased the area of TiO2 exposed to UV light, thereby endowing starch cryogel with ethylene removal capacity. The photocatalytic performance of scavenger reached the maximum ethylene degradation efficiency of 89.60 % when the TiO2 loading was 3 %. Ultrasonic treatment interrupted starch molecular chains and then promoted their rearrangement, increasing the material specific surface area from 54.6 m2/g to 225.15 m2/g and improving the ethylene degradation efficiency by 63.23 % compared with the non-sonicated cryogel. Furthermore, the scavenger exhibits good practicability for removing ethylene as a banana package. This work provides a new carbohydrate-based ethylene scavenger, utilizing as a non-food contact inner filler of F&V packaging in practical applications, which exhibits great potential in F&V preservation and broadens the application fields of starch.

Electronic and magnetic properties of charged point defects in monolayer CrI3.

The two-dimensional magnetic material CrI3 has gained considerable attention owing to its promising applications in photoelectric and spin-related devices. Recently, various structural defects in CrI3 have been identified; however, the charge states of these defects have been mainly ignored. Here, we report on an investigation of the charged defects in monolayer CrI3, focused on the electronic and magnetic properties of the five most stable point defects using first-principles calculations. For positively charged I vacancies and negatively charged Cr vacancies, a blue- and red-shift of defect states near the Fermi level can be observed because of the atom relaxation. Our results also indicate that, among the five defects, the Cr interstitial defect has the smallest ionization energy of 0.34 eV, which makes its ionization easiest. Furthermore, a 0.2 µB enhancement of the magnetic moment on the nearest Cr atom can be found for the I vacancy and Cr interstitial defect. The investigation contributes to the atomic-scale comparison and understanding of the charged defects of monolayer CrI3.

Nigericin treatment activates endoplasmic reticulum apoptosis pathway in goldfish kidney leukocytes.

Nigericin has been reported to induce apoptosis and pyroptosis in mammalian models. However, the effects and mechanism underlying the immune responses of teleost HKLs induced by nigericin remain enigmatic. To decipher the mechanism after nigericin treatment, the transcriptomic profile of goldfish HKLs was analyzed. The results demonstrated that a total of 465 differently expressed genes (DEGs) with 275 up-regulated and 190 down-regulated genes were identified between the control and nigericin treated groups. Among them, the top 20 DEG KEGG enrichment pathways were observed including apoptosis pathways. In addition, the expression level of selected genes (ADP4, ADP5, IRE1, MARCC, ALR1, DDX58) by quantitative real-time PCR showed a significant change after treatment with nigericin, which was generally identical to the expression patterns of the transcriptomic data. Furthermore, the treatment could induce cell death of HKLs, which was confirmed by LDH release and annexin V-FITC/PI assays. Taken together, our results support the idea that nigericin treatment might activate the IRE1-JNK apoptosis pathway in goldfish HKLs, which will provide insights into the mechanisms underlying HKLs immunity towards apoptosis or pyroptosis regulation in teleosts.

Structure, thermal stability, and in vitro digestibility of rice starch-protein hydrolysate complexes prepared using different hydrothermal treatments.

In this study, rice starch-protein hydrolysate (WPH-S) complexes with high resistant starch (RS) content were prepared by heat-moisture treatment (HMT) and annealing (ANN). The effects of different hydrothermal treatments on the structure and thermal stability of the WPH-S complexes and their relationship with starch digestibility were further discussed. The results showed that RS contents of ANN-WPH-S complexes (35.09-40.26 g/100 g) were higher than that of HMT-WPH-S complexes (24.15-38.74 g/100 g). Under hydrothermal treatments, WPH decreased the hydrolysis kinetic constant (k) of starch form 4.07 × 10-2-4.63 × 10-2 min-1 to 3.29 × 10-2-3.67 × 10-2 min-1. HMT and ANN promoted hydrogen bonding between WPH and starch molecules, thus increasing the molecular size of starch. In addition, the shear stability of WPH-S mixture was improved with the hysteresis loop area decreased after HMT/ANN treatments, resulting in a more stable structure. Most importantly, the hydrothermal treatment made the scatterers of WPH-S complexes denser and the surface smoother. Especially after ANN treatment, the WPH60-S complex formed a denser aggregate structure, which hindered the in vitro digestion of starch to a certain extent. These results enrich our understanding of the regulation of starch digestion by protein hydrolysates under different hydrothermal treatments and have guiding significance for the development of foods with a low glycemic index.

Effect of copper sulphate on Cryptocaryon irritans based on metabolome analysis.

Cryptocaryon irritans is one of the most harmful marine parasites in mariculture. Copper sulphate is often used to kill parasites and the influence of copper sulphate on the tomont stage of C. irritans was explored in this study. The results showed that excystment rate was not significantly affected when tomonts were exposed to 5 mg/L (76.7%) and 10 mg/L (78.9%) of copper sulphate for 3 h. However, excystment rate was significantly inhibited when exposed to 15 mg/L (33.3%) for 3 h and 5 mg/L (28.9%), 10 mg/L (33.3%) and 15 mg/L (33.3%) for 6 h. After treatment with high concentrations of copper sulphate, the interior of the tomonts was fuzzy under the microscope, and the division process could not be observed. Metabolomic results combined with preliminary transcriptome analysis results showed that the tomonts were induced to produce linoleate, riboflavin, inositol and other substances under the stress of Cu2+ , which affected the antioxidant mechanism of the body. Using MDA content determination and antioxidant enzyme activity analysis, copper sulphate was found to cause oxidative damage to tomonts by affecting the generation of metabolites, leading to the death of tomonts.

Starch digestion retarded by wheat protein hydrolysates with different degrees of hydrolysis.

Wheat protein hydrolysates (WPH) were prepared by pepsin hydrolysis for 30, 60, and 120 min (WPH30, WPH60, and WPH120). The mixed system of rice starch and WPH was hydrothermally treated to explore the effect of WPH with different degrees of hydrolysis on starch digestion. WPH reduced the first-order rate coefficient (k) of starch digestion. Especially, WPH30 reduced the k value the most and formed the highest slowly digestible starch content due to the entanglement of starch chains and long-chain peptides. WPH60 and WPH120 with more hydrophobic peptides and polar amino acids than WPH30 tended to form hydrogen bonds with starch molecules due to less steric hindrance. Particularly, the complexation of WPH60 promoted the formation of dense aggregate structure and hindered the enzymatic hydrolysis of starch to a certain extent, thereby increasing the resistant starch content. These findings provide significant guidance for the preparation of hypoglycemic reformed food.