Low Molecular Weight Fraction Research Articles

Potential of algae-derived alginate oligosaccharides and β-glucan to counter inflammation in adult zebrafish intestine.

Alginate oligosaccharides (AOS) are natural bioactive compounds with anti-inflammatory properties. We performed a feeding trial employing a zebrafish (Danio rerio) model of soybean-induced intestinal inflammation. Five groups of fish were fed different diets: a control (CT) diet, a soybean meal (SBM) diet, a soybean meal+β-glucan (BG) diet and 2 soybean meal+AOS diets (alginate products differing in the content of low molecular weight fractions - AL, with 31% < 3kDa and AH, with 3% < 3kDa). We analyzed the intestinal transcriptomic and plasma metabolomic profiles of the study groups. In addition, we assessed the expression of inflammatory marker genes and histological alterations in the intestine. Dietary algal β-(1, 3)-glucan and AOS were able to bring the expression of certain inflammatory genes altered by dietary SBM to a level similar to that in the control group. Intestinal transcriptomic analysis indicated that dietary SBM changed the expression of genes linked to inflammation, endoplasmic reticulum, reproduction and cell motility. The AL diet suppressed the expression of genes related to complement activation, inflammatory and humoral response, which can likely have an inflammation alleviation effect. On the other hand, the AH diet reduced the expression of genes, causing an enrichment of negative regulation of immune system process. The BG diet suppressed several immune genes linked to the endopeptidase activity and proteolysis. The plasma metabolomic profile further revealed that dietary SBM can alter inflammation-linked metabolites such as itaconic acid, taurochenodeoxycholic acid and enriched the arginine biosynthesis pathway. The diet AL helped in elevating one of the short chain fatty acids, namely 2-hydroxybutyric acid while the BG diet increased the abundance of a vitamin, pantothenic acid. Histological evaluation revealed the advantage of the AL diet: it increased the goblet cell number and length of villi of the intestinal mucosa. Overall, our results indicate that dietary AOS with an appropriate amount of < 3kDa can stall the inflammatory responses in zebrafish.

Cadmium-treatment efficiency and membrane fouling during electrodialysis of wastewater discharged from zinc smelting

Zinc smelting wastewater contains high concentrations of Cd. Here, the treatment efficiency of Cd using electrodialysis was evaluated. In addition, scale accumulation of ion-exchange membrane (IEM) was analyzed, and fouling control was studied. The results showed that spacers effectively improved the limiting current density but accelerated foulant accumulation. The Cd-treatment efficiency improved to 85.4% without a spacer. Dissolved organic carbon (DOC) and hydrophobic DOC levels in diluted water decreased by 0.65 mg L−1 and 2.1 mg L−1, respectively; in contrast, hydrophilic DOC level increased by 1.45 mg L−1. Some of the hydrophobic DOC in the diluted water was converted to hydrophilic DOC and subsequently to low-molecular-weight (LMW) DOC. DOC level in the concentrated water did not change substantially, but the LMW fraction of the hydrophilic DOC increased. In the cation-exchange membrane, a material composed of calcium sulfate accumulated in the bottom layer, and hydroxides of divalent and trivalent ions accumulated on top of it. In contrast, the anion-exchange membrane was fouled by humic substances. In terms of fouling control, physical and acid cleaning of IEMs was more effective than the reversal operation.

ACTION OF VENOM OF VIPERA LEBETINA ON BLOOD COAGULATION in vitro

Aim. In this study we focused on the search of fibrinogen-targeted proteases in the venom of Vipera lebetina. Methods. Fractionation of the venom was performed using FPLC chromatographic system Acta Prime on Q Sepharose. Analysis of protein mixtures was performed using SDS-PAGE. Аction on blood coagulation system was analyzed using APTT assay [2]. Proteolytic action on fibrinogen and identification of protein components with fibrinolytic activity was performed using electrophoresis of mixture of fibrinogen solution (2 mg/ml) with venom`s fractions. For a comprehensive evaluation of the effect of the obtained fractions on hemostasis, an original approach with modified aggregatometry was used [3]. This approach made it possible to take into account the ability of fractions to activate platelets, initiate blood coagulation, or inhibit platelet aggregation. Hemolytic action of fractions was estimated using fresh human red cells. Amount of released hemoglobin was estimated by spectrophotometry on Optizen POP. Results. Crude venom of V. lebetina was fractionated using ion-exchange chromatography on Q Sepharose. Elution was performed using a stepwise gradient of NaCl (0.1, 0.2, 0.3, 0.5, and 0.7 M NaCl) in 0.05 M Tris-HCl buffer at pH 8.3. Fractions eluted at 0.1 and 0.2 M of NaCl contained several proteins with different molecular weights ranging from 75 kDa to low molecular weight fractions according to the SDS-PAGE. Proteins that cleave α- and β-chains of fibrinogen were found in fractions 0.1 and 0.2, indicating the presence of an enzyme with fibrinogenolytic activity in the venom of V. lebetina. The fractions 0.3, 0.5, and 0.7 did not show any significant fibrinogenolytic activity. After platelet aggregation study we concluded that fraction 0.1 contained a protein with fibrinogenolytic activity. An increase in platelet aggregation was observed for the fraction 0.2 after the addition of ADP. This may indicate the presence of an active compound that promotes platelet aggregation. Further research is necessary to determine its nature. Fractions 0.3, 0.5, and 0.7 had no effect on platelet aggregation. A decrease in blood plasma clotting time in APTT to 5 s and 7 s, compared to a control value of 70 s, was shown for fractions eluted at NaCl concentrations of 0.1 M and 0.2 M, respectively. The fractions 0.3, 0.5 had only a slight effect on reducing blood plasma clotting. A slightly increased level of hemolysis was shown in the presence of the unbound fraction and the whole venom. It can be suggested that proteins with phospholipase activity are present in the non-binded fraction. Conclusions. Thus, fibrinogen-specific proteases, hemolytic agents, activators of blood clotting were found in the venom of Vipera lebetina. Most of these compounds must to be purified and can be used for basic biochemical research.

Inhibition of Cytomegalovirus by Pentacta pygmaea Fucosylated Chondroitin Sulfate Depends on Its Molecular Weight.

Many viruses attach to host cells by first interacting with cell surface proteoglycans containing heparan sulfate (HS) glycosaminoglycan chains and then by engaging with specific receptor, resulting in virus entry. In this project, HS-virus interactions were targeted by a new fucosylated chondroitin sulfate from the sea cucumber Pentacta pygmaea (PpFucCS) in order to block human cytomegalovirus (HCMV) entry into cells. Human foreskin fibroblasts were infected with HCMV in the presence of PpFucCS and its low molecular weight (LMW) fractions and the virus yield at five days post-infection was assessed. The virus attachment and entry into the cells were visualized by labeling the purified virus particles with a self-quenching fluorophore octadecyl rhodamine B (R18). The native PpFucCS exhibited potent inhibitory activity against HCMV specifically blocking virus entry into the cell and the inhibitory activities of the LMW PpFucCS derivatives were proportional to their chain lengths. PpFucCS and the derived oligosaccharides did not exhibit any significant cytotoxicity; moreover, they protected the infected cells from virus-induced lytic cell death. In conclusion, PpFucCS inhibits the entry of HCMV into cells and the high MW of this carbohydrate is a key structural element to achieve the maximal anti-viral effect. This new marine sulfated glycan can be developed into a potential prophylactic and therapeutic antiviral agent against HCMV infection.

Source apportionment of polycyclic aromatic hydrocarbons in New York/New Jersey Harbour sediment

AbstractData on polycyclic aromatic hydrocarbons (PAHs) measured in surface sediment and cores in the New York/New Jersey Harbour under the Contamination Assessment and Reduction Project (CARP) was examined via Positive Matrix Factorization (PMF), which revealed six sources. Two represented the higher and lower molecular weight (MW) fractions of coal tar and/or creosote (pyrogenic) sources and explained 49% of PAH mass in the sediment samples. Two sources were related to uncombusted petroleum (petrogenic) sources, such as heavy fuel oil and crude oil, and explained 30% of PAH mass. The final two sources were related to combustion (pyrogenic) sources such as gasoline‐ and diesel‐fuelled vehicles and explained 21% of the PAH mass. Sediment cores revealed that Σ22PAH increased from the pre‐industrial period until about 1980 and then decreased because of efforts to control water pollution via mechanisms such as the Clean Water Act.

Perspectives in the Application of High, Medium, and Low Molecular Weight Oat β-d-Glucans in Dietary Nutrition and Food Technology—A Short Overview

For centuries human civilization has cultivated oats, and now they are consumed in various forms of food, from instant breakfasts to beverages. They are a nutrient-rich food containing linear mixed-linkage (1 → 3) (1 → 4)-β-d-glucans, which are relatively well soluble in water and responsible for various biological effects: the regulation of the blood cholesterol level, as well as being anti-inflammatory, prebiotic, antioxidant, and tumor-preventing. Numerous studies, especially in the last two decades, highlight the differences in the biological properties of the oat β-d-glucan fractions of low, medium, and high molecular weight. These fractions differ in their features due to variations in bioavailability related to the rheological properties of these polysaccharides, and their association with food matrices, purity, and mode of preparation or modification. There is strong evidence that, under different conditions, the molecular weight may determine the potency of oat-extracted β-d-glucans. In this review, we intend to give a concise overview of the properties and studies of the biological activities of oat β-d-glucan preparations depending on their molecular weight and how they represent a prospective ingredient of functional food with the potential to prevent or modulate various pathological conditions.

Differences in the spectral characteristics of dissolved organic matter binding to Cu(II) in wetland soils with moisture gradients

The environmental behavior of heavy metals in soil is significantly regulated by their binding with dissolved organic matter (DOM), which is affected by soil moisture contents. However, the mechanism of this interaction in soils with varying moisture is still not well understood. Using a combination of ultrafiltration, Cu(II) titration, and multispectral (ultraviolet-visible absorption, 3D fluorescence, Fourier transform infrared) analysis techniques, we studied the differences in the spectral characteristics and Cu(II) binding properties of soil dissolved organic matter (DOM) and its different molecular weight (MW) fractions with moisture gradients. We found that the abundance and spectral characters of soil DOM changed with increasing soil moisture, i.e., the increase in abundance while the decrease in aromaticity and humification index. The components of DOM, shown by Fluorescence region-integration (FRI) analysis, also changed, with an increase in the proportion of protein-like substances and a decrease of humic-like and fulvic-like substances. The overall Cu(II) binding potential of soil DOM diminished with increasing soil moisture, as indicated by the fluorescence parallel factor (PARAFAC) analysis. This is aligns with the changes in DOM composition, as the humic-like and fulvic-like fractions exhibited higher Cu(II) binding potential compared to the protein-like fractions. The low MW fraction of the MW-fractionated samples showed a stronger binding potential for Cu(II) compared to the high MW fraction. Finally, the active binding site of Cu(II) in DOM, as revealed by UV-difference spectroscopy and 2D-FTIR-COS analysis, decreased with increasing soil moisture, with the order of preferentially functional groups shifting from OH, NH, and CO to CN and CO. This study emphasizes the impact of moisture variations on the characteristics of DOM and its interaction with Cu(II), providing insight into the environmental fate of heavy metal contaminants in soil in areas with alternating land and water conditions.

Identification of Antioxidative Peptides Derived from Arthrospira maxima in the Biorefinery Process after Extraction of C-Phycocyanin and Lipids.

Arthrospira maxima has been identified as a sustainable source of rich proteins with diverse functionalities and bioactivities. After extracting C-phycocyanin (C-PC) and lipids in a biorefinery process, the spent biomass still contains a large proportion of proteins with potential for biopeptide production. In this study, the residue was digested using Papain, Alcalase, Trypsin, Protamex 1.6, and Alcalase 2.4 L at different time intervals. The resulting hydrolyzed product with the highest antioxidative activity, evaluated through their scavenging capability of hydroxyl radicals, superoxide anion, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), was selected for further fractionation and purification to isolate and identify biopeptides. Alcalase 2.4 L was found to produce the highest antioxidative hydrolysate product after four-hour hydrolysis. Fractionating this bioactive product using ultrafiltration obtained two fractions with different molecular weights (MW) and antioxidative activity. The low-molecular-weight fraction (LMWF) with MW <3 kDa had higher DPPH scavenging activity with the IC50 value of 2.97 ± 0.33 compared to 3.76 ± 0.15 mg/mL of the high-molecular-weight fraction (HMWF) with MW >3 kDa. Two stronger antioxidative fractions (F-A and F-B) with the respective significant lower IC50 values of 0.83 ± 0.22 and 1.52 ± 0.29 mg/mL were isolated from the LMWF using gel filtration with a Sephadex G-25 column. Based on LC-MS/MS analysis of the F-A, 230 peptides derived from 108 A. maxima proteins were determined. Notably, different antioxidative peptides possessing various bioactivities, including antioxidation, were detected with high predicted scores together with in silico analyses on their stability and toxicity. This study established knowledge and technology to further value-add to the spent A. maxima biomass by optimizing hydrolysis and fraction processes to produce antioxidative peptides with Alcalase 2.4 L after two products already produced in a biorefinery. These bioactive peptides have potential applications in food and nutraceutical products.

Molecular Characterization of Aged Bitumen with Selective and Nonselective Ionization Methods by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. 3. Investigation on Molecular Fractions Obtained by Gel Permeation Chromatography

Long-term aging of bitumen causes formation of oxidation products that can be associated with polar and strongly interacting functional groups leading to a tremendous influence on bitumen properties. This can lead to an aggregation of the most polar molecules in the asphaltene fraction. Other types of aggregation have also been described in the literature, with larger and more aliphatic compounds through wax interactions. These aggregate phases can be studied using gel permeation chromatography (GPC) for the separation of heavy petroleum products based on their molecular weight. Three molecular weight fractions of native bitumen and its aged state by a long-term pressure aging vessel (PAV-72h) were obtained with low molecular weight (LMW), medium molecular weight (MMW), and high molecular weight (HMW) fractions. To characterize oxidative aging on each fraction at the molecular level, Fourier transform ion cyclotron resonance (FTICR) was used. Indeed, the ultrahigh resolution and mass accuracy of this analyzer allow to attribute molecular formulas to each signal of complex matrices unambiguously. An electrospray ionization (ESI) source was used to selectively ionize acid molecules, while atmospheric pressure photoionization source (APPI) was used to have a nonselective ionization of low polarity molecules from bitumen. With both ionization sources, the LMW fraction exhibited the most aromatic and heteroelement-enriched molecules. In terms of variation with aging, the LMW fraction showed the most pronounced variations. Molecular maps evidenced the occurrence of low DBE oxidation markers for Oz and OzSy families. Low variations were observed on distributions of MMW and HMW fractions. Concerning HMW, these unexpected results, obtained by ESI and APPI ionization sources, may be due to a protection of the molecules against oxidation within aggregates. In addition, APPI results underlined that the higher molecular weight distribution containing most of the aggregate molecules was mainly composed of large aliphatic molecules. Overall, this study demonstrated that oxidation products corresponded to small and aliphatic molecules majorly found in the LMW fraction and that aggregated molecules form HMW fraction were relatively protected from oxidation.

Ultrasound-assisted H2O2 directional-modification of powdered activated carbon for the enhanced adsorption of secondary effluent organic matter from printing and dyeing processes

The physicochemical properties of powdered activated carbon (PAC) are important factors affecting its adsorption performance, which is also related to the characteristics of target organic pollutants. In this study, the key indicators affecting the adsorption performance of PAC were identified, and the physicochemical properties of PACs were modified by hydrogen peroxide and/or ultrasound in a targeted manner to improve the adsorption performance. The results indicated the adsorption properties of printing and dyeing secondary effluent organic matter (EfOM) in terms of CODcr and UV absorbance at 254 nm (UV254) positively correlated with mesoporous volume, average pore size and acid group content of PAC. After modification, the mesoporous volume and average pore size of PAC increased, and the number of acidic groups increased, thus enhancing the adsorption efficiency. EfOM removal characteristics showed that PAC preferentially adsorbed unsaturated bonds or aromatic compounds, tryptophan-like proteins, soluble microbial metabolites and low molecular weight fractions below 1 kDa. In addition, the relative contents of specific surface area, pore volume and oxygen-containing functional groups (O-CO, C-OH, CO/O-C-O) of PAC decreased after adsorption, indicating that EfOM adsorption was a physical and chemical process, including pore filling, hydrophobic interaction and chemical bond force interaction. In general, PACs with larger mesoporous volume, average pore size and abundant acid groups possessed good adsorption performance towards EfOM.

Critical minority fractions causing membrane fouling in reclaimed water: Fouling characteristics, mechanisms and control strategies

In regard to membrane-based technologies of wastewater reclamation, the reported key foulants were faced with dilemma that they could not be effectively separated and extracted from reclaimed water for thorough investigation. In this study, the crucial foulants were proposed as “critical minority fraction (FCM)”, representing the fraction with molecular weight (MW) > 100 kDa which could be easily separated by physical filtration using MW cut-off membrane of 100 kDa with fairly high recovery ratio. FCM with low dissolved organic carbon (DOC) concentration (∼1 mg/L) accounted for less than 20% of the total DOC in reclaimed water, while contributed to more than 90% of the membrane fouling, and thus FCM could be considered as a “perfect criminal” causing membrane fouling. Furthermore, pivotal fouling mechanism was attributed to the significant attractive force between FCM and membranes, which led to severe fouling development due to the aggregation of FCM on membrane surface. Fluorescent chromophores of FCM were concentrated in regions of proteins and soluble microbial products, with proteins and polysaccharides accounted for 45.2% and 25.1% of the total DOC, specifically. FCM was further fractionated into six fractions, among which hydrophobic acids and hydrophobic neutrals were the dominant components in terms of DOC content (∼80%) as well as fouling contribution. Regarding to these pronounced properties of FCM, targeted fouling control strategies including ozonation and coagulation were applied and proved to achieve remarkable fouling control effect. High-performance size-exclusion chromatography results suggested that ozonation achieved distinct transformation of FCM into low MW fractions, while coagulation removed FCM directly, thus leading to effective fouling alleviation. Therefore, the investigation of the critical foulants was expected to help glean valuable insight into the fouling mechanism and develop targeted fouling control technologies in practical applications.

Surface-enhanced Raman spectroscopy of centrifuged blood serum samples of diabetic type II patients by using 50KDa filter devices

Blood serum contains essential biochemical information which are used for early disease diagnosis. Blood serum consisted of higher molecular weight fractions (HMWF) and lower molecular weight fractions (LMWF). The disease biomarkers are lower molecular weight fraction proteins, and their contribution to disease diagnosis is suppressed due to higher molecular weight fraction proteins. To diagnose diabetes in early stages are difficult because of the presence of huge amount of these HMWF. In the current study, surface-enhanced Raman spectroscopy (SERS) are employed to diagnose diabetes after centrifugation of serum samples using Amicon ultra filter devices of 50 kDa which produced two fractions of whole blood serum of filtrate, low molecular weight fraction, and residue, high molecular weight fraction. Furthermore SERS is employed to study the LMW fractions of healthy and diseased samples. Some prominent SERS bands are observed at 725 cm−1, 842 cm−1, 1025 cm−1, 959 cm−1, and 1447 cm−1 due to small molecular weight proteins, and these biomarkers helped to diagnose the disease early stage. Moreover, chemometric techniques such as principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) are employed to check the potential of surface-enhanced Raman spectroscopy for the differentiation and classifications of the blood serum samples. SERS can be employed for the early diagnosis and screening of biochemical changes during type II diabetes.

Rainbow Trout (Oncorhynchus mykiss) as Source of Multifunctional Peptides with Antioxidant, ACE and DPP-IV Inhibitory Activities.

The present study aimed at characterizing the possible biological activities of the multifunctional low molecular weight fractions (<3 kDa) peptides isolated from rainbow trout (Oncorhynchus mykiss) obtained by enzymatic hydrolysis. The fish protein hydrolysate (FPH) was tested for its antioxidant property along with its angiotensin converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. In particular, the 2,2-diphenyl-1-picrylhydrazyl (DPPH), the ferric reducing antioxidant power (FRAP), the oxygen radical absorbance capacity (ORAC) assay and the 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays were carried out for the evaluation of the in vitro antioxidant activity. The cell-free ACE and DPP-IV inhibitory activity assays were also estimated, showing a dose-dependent inhibition. These biological properties were additionally quantified at the cellular level using human intestinal Caco-2 cells. Namely, the antioxidant activity was determined by evaluating the capability of the hydrolysate to reduce the H2O2-induced reactive oxygen species (ROS) and lipid peroxidation levels, and the DPP-IV activity assays show a reduction of enzyme activity of up to 27.57 ± 3.7% at 5 mg/mL. The results indicate that Oncorhynchus mykiss-derived peptides may have potential employment as health-promoting ingredients.

Properties and metal binding behaviors of sediment dissolved organic matter (SDOM) in lakes with different trophic states along the Yangtze River Basin: A comparison and summary

The nature of sediment dissolved organic matter (SDOM) can reflect the environmental background, nutritional status and human activities and is an important part of lakes. The differences in the binding capacity of heavy metals and organic matter in lake sediments with different trophic states at the catchment scale and the mechanism of the differences in binding are still unclear. To solve this problem, we collected bulk SDOMs (< 0.7 μm) from 6 respective lakes (from upstream to downstream) in the Yangtze River Basin (YRB) to qualitatively and quantitatively characterize their properties and metal binding behaviors using excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-FARAFAC) and two-dimensional correlation spectroscopy of synchronous fluorescence spectroscopy and Fourier transform infrared spectroscopy (2D-SF-COS and 2D-FTIR-COS). The results showed that sediment dissolved organic carbon (SDOC) was mainly enriched in low molecular weight (LMW: < 1 kDa) fractions. The total fluorescence intensity (Fmax) of SDOM from upstream was larger than that from downstream (p = 0.033), and humic-like fluorophores were dominant in these lakes. The Fmax of sediment humic-like components (C1+C2) was closely related to the trophic levels of the lakes. Protein-like substances and oxygen-containing functional groups (C−OH, C=O, and C−O) were preferred in the reaction between SDOM and copper (Cu2+) or cadmium (Cd2+), while a unique binding path was exhibited in the moderately eutrophic DCL. In terms of fluorophore types, higher Cu2+-binding abilities (LogKCu) were observed in the humic-like matter for the lakes in the upper reaches and tryptophan-like matter for the lakes from the midstream and downstream areas of the YRB. Although Cd2+ complexed only with humic-like matter, LogKCd was higher than LogKCu. In terms of molecular weight (MW), the LogKCu/Cd of components were enhanced after MW fractionation. The HMW (0.7 μm – 1 kDa) components possessed higher LogKCu in most lakes (except for CHL and C4). The different fluorophores and molecular weight fractions in SDOM make an important contribution to reducing the ecological risks of heavy metals in lakes.

Levan Production in Shake Flask and Fermenter Influence of Feeding Strategy on Levan Yield and Molecular Weight Distribution

Effect of feeding strategy on levan production was studied in a shake flask and a 5 L lab scale fermenter. In a shake flask, levan specific substrate yield (YP/S) increased from 0.35 g levan/g sucrose to 0.48 g levan/g sucrose with repeated batch feeding. In a 3 L reactor, levan productivity of 7.18 g/L h was obtained with the fed-batch mode of fermentation. The gel permeation chromatography results indicate that higher initial sucrose concentration under the fed-batch mode operation resulted in the formation of low molecular weight fractions (4 and 10 kDa). Thus, fed-batch fermentation favors levan production resulting in higher yield and productivity and also affects the molecular weight distribution of the biopolymer.

Selection of Temperature regimes for conditioning and flotation of diamond-bearing kimberlite with compound collectors

The condition for stable fixation of a collector on the surface of diamonds and their flotation is the use of collectors of the optimal fractional composition and the choice of the optimum temperature regime of the process. To determine the parameters of the diamond flotation regime, the regularities of the phase transitions of asphaltene-tar fractions at increasing temperature and diluting F-5 with technical diesel fraction were established. It was demonstrated that increasing the collector temperature leads to the transfer of asphaltenetar fractions to a dissolved and finely dispersed state. To an even greater extent, dissolving asphaltene-tar fractions is facilitated by the addition of medium- and low-molecular weight fractions of oil, for instance, a technical diesel fraction.It was revealed that the KM-10, KM-14, and KM-18 reagents, being compounds of F-5 fuel oil with technical diesel fraction (10–18 % DF), were characterized by optimal viscosity and ability to displace aqueous phase from a diamond surface, thus ensuring stable hydrophobization and high floatability of diamonds. The optimal temperature regime has been selected, which involved maintaining the temperature at the stage of conditioning with the collector at +30–40 °С, at which the maximum selective fixation of compound collectors on the diamond surface, characterized by the value of the limiting wetting angle, was achieved. The flotation tests have confirmed that the best results are achieved at a temperature of +30–40 °С at the conditioning stage and +14–24 °С at the flotation stage. At +24 °С, the best results were obtained for the relatively less diluted KM-10 and KM-14 fuel oils obtained by diluting F-5 fuel oil with a technical diesel fraction at the diluent volume fractions of 10 and 14 %. The diamond recovery achieved in the flotation tests was 3.8–4.5 % higher than when using the traditional collector, F-5 fuel oil. At +14 °С, the highly diluted fuel oil, KM-18 with a volume fraction of 18 % of the technical diesel fraction, demonstrated better collecting abilities.The optimal compositions of the collector and the regimes of feed preparation and flotation were tested at a foam separation unit. The tests showed that it is possible to increase diamond recovery into concentrate by 2.3–4.5 %. The recommendations are provided on the use of thermal conditioning in the foam separation cycle and maintaining the conditioning medium temperature at +30–40 °С and the foam separation temperature at +14–24 °С.

Chemical characterization and biological effect of exopolysaccharides synthesized by Antarctic yeasts Cystobasidium ongulense AL101 and Leucosporidium yakuticum AL102 on murine innate immune cells.

The current study aimed to investigate exopolysaccharides (EPSs) produced by two Antarctic yeasts isolated from soil and penguin feathers samples collected on Livingston Island (Antarctica). The strains were identified as belonging to the species Leucosporidium yakuticum (LY) and Cystobasidium ongulense (CO) based on molecular genetic analysis. The EPS production was investigated using submerged cultivation. Different chemical, chromatographic, and spectral analyses were employed to characterize EPSs. LY accumulated 5.5g/L biomass and 4.0g/L EPS after 120h of cultivation, while CO synthesized 2.1g/L EPS at the end of cultivation, and the biomass amount reached 5.5g/L. LY-EPS was characterized by a higher total carbohydrate content (80%) and a lower protein content (18%) by comparison with CO-EPS (62%, 30%). The LY-EPS mainly consisted of mannose (90mol%), whereas CO-EPS had also glucose, galactose, and small amounts of uronic acids (8-5mol%). Spectral analyses (FT-IR and 1D, 2D NMR) revealed that LY-EPS comprised a typical β-(1 → 4)-mannan. Branched (hetero)mannan, together with β/α-glucans constituted the majority of CO-EPS. Unlike LY-EPS, which had a high percentage of high molecular weight populations, CO-EPS displayed a large quantity of lower molecular weight fractions and a higher degree of heterogeneity. LY-EPS (100 ng/mL) elevated significantly interferon gamma (IFN-γ) production in splenic murine macrophages and natural killer (NK) cells. The results indicated that newly identified EPSs might affect IFN-γ signaling and in turn, might enhance anti-infectious responses. The data obtained also revealed the potential of EPSs and yeasts for practical application in biochemical engineering and biotechnology.

In vivo anti-tumor activity of Lignosus rhinocerus TM02® using a MCF7-xenograft NCr nude mice model

Ethnopharmacological relevanceLignosus rhinocerus (Cooke) Ryvarden (also known as Tiger Milk mushroom, TMM), is a basidiomycete belonging to the Polyporaceae family. It has been documented to be used by traditional Chinese physicians and indigenous people in Southeast Asia to treat a variety of illnesses, such as gastritis, arthritis, and respiratory conditions, as well as to restore patients' physical well-being. TMM has also been used in folk medicine to treat cancer. For example, people from the indigenous Kensiu tribe of northeast Kedah (Malaysia) apply shredded TMM sclerotium mixed with water directly onto breast skin to treat breast cancer, while Chinese practitioners from Hong Kong, China prescribe TMM sclerotium as a treatment for liver cancer. L. rhinocerus has previously been demonstrated to possess selective anti-proliferative properties in vitro, however pre-clinical in vivo research has not yet been conducted. Aim of studyThis study aimed to examine the anti-tumor activities of L. rhinocerus TM02®, using two different sample preparations [cold water extract (CWE) and fraction] via various routes of administration (oral and intraperitoneal) on an MCF7-xenograft nude mouse model. This study also investigated the inhibitory effect of TM02® CWE and its fractions against COX-2 in vitro using LPS-induced RAW264.7 macrophages, on the basis of the relationship between COX-2 and metastasis, apoptosis resistance, as well as the proliferation of cancer cells. Materials and methodsThe first preparation, L. rhinocerus TM02® sclerotium powder (TSP) was dissolved in cold water to obtain the cold water extract (CWE). It was further fractionated based on its molecular weight to obtain the high (HMW), medium (MMW) and low (LMW) molecular weight fractions. The second preparation, known as the TM02® rhinoprolycan fraction (TRF), was obtained by combining the HMW and MMW fractions. TSP was given orally to mimic the daily consumption of a supplement; TRF was administered intraperitoneally to mimic typical tumorous cancer treatment with a rapid and more thorough absorption through the peritoneal cavity. Another experiment was conducted to examine changes in COX-2 activity in LPS-induced RAW264.7 macrophages after a 1-h pre-treatment with CWE, HMW, and MMW. ResultsOur results revealed that intraperitoneal TRF-injection (90 μg/g BW) for 20 days reduced initial tumor volume by ∼64.3% (n = 5). The percentage of apoptotic cells was marginally higher in TRF-treated mice vs. control, suggesting that induction of apoptosis as one of the factors that led to tumor shrinkage. TSP (500 μg/g BW) oral treatment (n = 5) for 63 days (inclusive of pre-treatment prior to tumor inoculation) effectively inhibited tumor growth. Four of the five tumors totally regressed, demonstrating the effectiveness of TSP ingestion in suppressing tumor growth. Although no significant changes were found in mouse serum cytokines (TNF-α, IL-5, IL-6 and CCL2), some increasing and decreasing trends were observed. This may suggest the immunomodulatory potential of these treatments that can directly or indirectly affect tumor growth. Pre-treatment with CWE, HMW and MMW significantly reduced COX-2 activity in RAW264.7 macrophages upon 24 h LPS-stimulation, suggesting the potential of L. rhinocerus TM02® extract and fractions in regulating M1/M2 polarization. ConclusionBased on the findings of our investigation, both the rhinoprolycan fraction and crude sclerotial powder from L. rhinocerus TM02® demonstrated tumor suppressive effects, indicating that they contain substances with strong anticancer potential. The antitumor effects of L. rhinocerus TM02® in our study highlights the potential for further explorations into its mechanism of action and future development as a prophylactic or adjunct therapeutic against tumorous cancer.

The inhibitory effect of dextranases from Bacillus velezensis and Pseudomonas stutzeri on Streptococcus mutans biofilm.

Dental caries is a breakdown of the teeth enamel due to harmful bacteria, lack of oral hygiene, and sugar consumption. The acid-producing bacterium Streptococcus mutans is the leading cause of dental caries. Dextranase is an enzyme that can degrade dextran to low molecular weight fractions, which have many therapeutic and industrial applications. The purpose of the present study was to isolate a novel dextranase-producing bacteria from a source (molasses). The cell-free extracts containing dextranases were tested as antibiofilm agents. Dextranase-producing bacteria were identified using phenotypic and genotypic methods such as 16S rRNA gene sequencing and enzymatic characterization. The highest six dextranase-producing bacterial isolates were Bacillus species. The best conditions for dextranase productivity were obtained after 72 hours of culture time at pH 7. The addition of glucose to the medium enhanced the production of the enzymes. The cell-free extract of the six most active isolates showed remarkable activity against biofilm formation by Streptococcus mutans ATCC 25175. The highest inhibition activities reached 60% and 80% for Bacillus velezensis and Pseudomonas stutzeri, respectively. Therefore, our study added to the current dextranase-producing bacteria with potential as a source of dextranases.

Structural Characterization and In Vivo Anti-Inflammatory Activity of Fucoidan from Cystoseira crinita (Desf.) Borry.

The aim of this study was to evaluate the effects of fucoidan isolated from C. crinita on histamine-induced paw inflammation in rats, and on the serum levels of TNF-α, IL-1β, IL-6, and IL-10 in rats during systemic inflammation response. The levels of TNF-α in a model of acute peritonitis in rats were also investigated. The isolated crude fucoidan was identified as a sulfated xylogalactofucan with high, medium, and low molecular weight fractions and a content of fucose of 39.74%, xylose of 20.75%, and galactose of 15.51%. Fucoidan from C. crinita showed better anti-inflammatory effects in the rat paw edema model, and this effect was present during all stages of the experiment. When compared to controls, a commercial fucoidan from F. vesiculosus, the results also displayed anti-inflammatory activity on the 60th, 90th, and 120th minute of the experiment. A significant decrease in serum levels of IL-1β in rats treated with both doses of C. crinita fucoidan was observed in comparison to controls, whereas TNF-α concentrations were reduced only in the group treated with fucoidan from C. crinita at the dose of 25 mg/kg bw. In the model of carrageenan-induced peritonitis, we observed a tendency of decrease in the levels of the pro-inflammatory cytokine TNF-α in peritoneal fluid after a single dose of C. crinita fucoidan, but this did not reach the statistical significance margin. Single doses of C. crinita fucoidan did not alter serum levels of the anti-inflammatory cytokine IL-10 in animals with lipopolysaccharide-induced systemic inflammation.