Small Molecular Weight Components Research Articles

Partitioning of proteins and small molecular weight compounds from alfalfa juice during ultrafiltration

Ribulose-1,5-biphosphate-carboxylase/oxygenase (RuBisCO) from alfalfa is a promising source of alternative food protein, but it is challenging to purify. Ultrafiltration shows potential for concentrating and fractionating RuBisCO from low molecular weight compounds present in the extracted juice, but there is limited information on their partitioning depending on the membrane pore size. Therefore, the objective of this study was to evaluate the partitioning of various compounds from the juice depending on membrane pore size. It was hypothesized that both membrane pore sizes will retain RuBisCO but might partition low molecular weight compounds within the matrix differently. RuBisCO was fully retained by both the 300 and 100 kDa polyethersulfone (PES) membranes, while ash (29.7%–35.4% dry matter (DM)), non-protein nitrogen (2.38%–2.53% DM), and free N-terminals (10.13–10.34 mg glutamic equivalent/100 mg DM) were transmitted through both membranes. The retentates showed a distinct yellow color when filtering with 100 kDa membranes, but not when using 300 kDa membranes. Although no significant differences in total polyphenol permeation were observed through a spectrophotometric assay, a metabolomics screening analysis showed that the 100 kDa membranes had less transmission of the flavonoids apigenin, chrysoeriol, tricin, and tricin glycosides, which might contribute to the yellow color. These results reiterate the importance of measuring individual polyphenols using hyphenated techniques as opposed to spectrophotometric total reducing capacity. Sixteen saponins were identified and their permeation was lower in the 100 than the 300 kDa membranes, indicating a better potential for higher degree of protein refinement for the latter. This study demonstrates for the first time the difference in partitioning of the small molecular weight components, using PES membranes of similar chemistry but different size, during ultrafiltration of alfalfa juice.

The safety assessment of tampons: illustration of a comprehensive approach for four different products.

We illustrate a comprehensive tampon safety assessment approach that assures products can be used safely. Material biocompatibility, vaginal mucosa assessment, vaginal microbiome evaluation, and in vitro assessment of potential risk of staphylococcal toxic shock syndrome expressed through growth of Staphylococcus aureus (S. aureus) and production of TSST-1 are the four essential portions of the approach. Post-marketing surveillance informs of possible health effects that warrant follow up. The approach meets or exceeds US and international regulatory guidance and is described through the example of four tampon products. Each product is comprised mostly of large molecular weight components (cotton, rayon, polymers) that cannot pass the vaginal mucosa, are widely used across the industry, and replete with a vast body of safety data and a long history of safe use in the category. Quantitative risk assessment of all small molecular weight components assured a sufficient margin of safety supporting their use. Vaginal mucosa assessment confirmed that pressure points, rough edges and/or sharp contact points were absent. A randomized cross-over clinical trial (ClinicalTrials.gov Identifier: NCT03478371) revealed favorable comfort ratings, and few complaints of irritation, burning, stinging, or discomfort upon insertion, wear, and removal. Adverse events were few, mild in severity, self-limited and resolved without treatment. Vaginal microbiota assessment in vitro presented no adverse effect on microbial growth. Culture-independent microbiome analyses from vaginal swab samples obtained during the clinical trial showed no differences attributable to tampon usage, but instead due to statistically significant subject-to-subject variability. Growth of S. aureus and TSST-1 toxin production in the presence of any of the four products in vitro were statistically significantly reduced when compared to medium control alone. The data from the four elements of the comprehensive safety assessment approach illustrated herein confirm that tampons evaluated using this system can be used safely for menstrual protection. A post-marketing surveillance system that monitors and responds to in-market experiences indicated in-use tolerability of the product among consumers, thus confirming the conclusions of the pre-marketing safety assessment.

A New Optimization Strategy of Highly Branched Poly(β-Amino Ester) for Enhanced Gene Delivery: Removal of Small Molecular Weight Components

Highly branched poly(β-amino ester) (HPAE) has become one of the most promising non-viral gene delivery vector candidates. When compared to other gene delivery vectors, HPAE has a broad molecular weight distribution (MWD). Despite significant efforts to optimize HPAE targeting enhanced gene delivery, the effect of different molecular weight (MW) components on transfection has rarely been studied. In this work, a new structural optimization strategy was proposed targeting enhanced HPAE gene transfection. A series of HPAE with different MW components was obtained through a stepwise precipitation approach and applied to plasmid DNA delivery. It was demonstrated that the removal of small MW components from the original HPAE structure could significantly enhance its transfection performance (e.g., GFP expression increased 7 folds at w/w of 10/1). The universality of this strategy was proven by extending it to varying HPAE systems with different MWs and different branching degrees, where the transfection performance exhibited an even magnitude enhancement after removing small MW portions. This work opened a new avenue for developing high-efficiency HPAE gene delivery vectors and provided new insights into the understanding of the HPAE structure-property relationship, which would facilitate the translation of HPAEs in gene therapy clinical applications.

Performance and mechanisms of dredged sludge dewaterability enhancement with slag-based polymeric titanium aluminum coagulant

In this work, blast furnace slag was successfully used to prepare five kinds of polymeric titanium aluminium flocculant (PTAC) with different polymerization degrees by two-step acid leaching method, which were applied as the effective dredged sludge conditioners. The results indicated that PTAC can obviously improve the sludge dewaterability. Compared with other four types of PTAC, PTAC0.6 showed the best sludge conditioning efficiency under the optimum dosage of 4 mg Al + Ti/g TSS. It can reduce the capillary suction time of the sediment by 81.4%, the specific resistance to filtration by 65.1%, and the moisture content of the mud cake from 81.9% to 45.81%. PTAC can significantly increase the zeta potential of the dredged sludge, while it has no obvious effect on the floc size D0.5. The electric neutralization substantially contributed to the conditioning of PTAC on dredged sludge dewatering. The concentration of dissolved organic carbon, total phosphorus in the residual water was significantly reduced after PTAC conditioning. PTAC can also remove large molecular weight components in dissolved organic matter by flocculation, or hydrolyze large molecular components into small and medium molecular weight components, furthermore reduce the concentration of these organic components. 3D-EEM analysis results showed that PTAC can effectively remove fulvic acid-like substances and some protein-like substances by flocculation, especially the removal effect of fulvic acid-like substances was more prominent.

Amino Acid Composition and Functional Properties of Different Molecular Weight Segments of Macadamia Peptides

In this study, macadamia peptides were produced by ultrasonic-assisted alkaline protease, and five components were separated by ultrafiltration centrifuge with different molecular weight (1kDa, 3kDa, 10kDa, 30kDa). The amino acid composition, solubility, water absorption capacity and emulsifying properties of five components were compared. Results showed that all macadamia peptide components were rich in amino acid species, the contents of essential and hydrophobic amino acids ranged from 189.59 to 281.10mg/g and 204.26 to 258.78mg/g, respectively. Meanwhile, the small molecular weight components (MP-1) showed the best solubility and water absorption capacity, large molecular weight components (MP-5) had the best emulsifying properties. This result indicated that the distribution of molecular weight had significant effects on the amino acid composition and functional properties of macadamia peptide components. This study provides a theoretical basis for the further development of macadamia peptide products.

Photodegradation of dissolved organic matter of chicken manure: Property changes and effects on Zn2+/Cu2+ binding property

Untreated livestock manure contains high concentrations of dissolved organic matter (DOM), which can enter the environment through leaching and eluviation, showing an important impact on the environment. In this research, fresh chicken manure from a large-scale chicken farm was collected as the source of DOM. The infrared spectrum of the original DOM was characterized. TOC analysis, UV spectrum and 3D fluorescence spectrum were used to measure the properties of DOM before and after photodegradation. Infrared spectroscopy results show that chicken manure DOM may contain aliphatic and aromatic compounds, alcohols, phenols, polysaccharides and some protein substances; In three systems, the order of TOC removal rates of DOM was water + UV system (85%) > > water + simulated sunlight system (7.2%) > ice + simulated sunlight system (4.5%); Changes of UV spectra, fluorescence spectra, molecular weight distribution and pH value show that, in three systems, as the illumination time increased, photodegradation reduced pH value of the systems, aromaticity and humus contents of DOM, while increased the proportion of medium and/or small molecular weight components of DOM. The amounts of all these changes were proportional to DOM photodegradation rates in the system. The binding ability of DOM with Cu2+ and Zn2+ in water solution decreased significantly after the photodegradation.

Elucidation of the mechanism of subunit exchange in \u03b1B crystallin oligomers

AlphaB crystallin (αB-crystallin) is a key protein for maintaining the long-term transparency of the eye lens. In the eye lens, αB-crystallin is a “dynamical” oligomer regulated by subunit exchange between the oligomers. To elucidate the unsettled mechanism of subunit exchange in αB-crystallin oligomers, the study was carried out at two different protein concentrations, 28.5 mg/mL (dense sample) and 0.45 mg/mL (dilute sample), through inverse contrast matching small-angle neutron scattering. Interestingly, the exchange rate of the dense sample was the same as that of the dilute sample. From analytical ultracentrifuge measurements, the coexistence of small molecular weight components and oligomers was detected, regardless of the protein concentration. The model proposed that subunit exchange could proceed through the assistance of monomers and other small oligomers; the key mechanism is attaching/detaching monomers and other small oligomers to/from oligomers. Moreover, this model successfully reproduced the experimental results for both dense and dilute solutions. It is concluded that the monomer and other small oligomers attaching/detaching mainly regulates the subunit exchange in αB-crystallin oligomer.

Double filtration plasmapheresis: Review of current clinical applications.

Double filtration plasmapheresis (DFPP) is a semi-selective blood purification modality derived from the plasma exchange (PE) modality. In the DFPP treatment, two types of filters with different pore sizes are used: a plasma separator and a plasma component separator. Blood is separated into plasma and blood cells using a plasma separator. The separated plasma is fractionated into large and small molecular weight components by a plasma component separator. Large molecular weight components, including pathogenic substances, are discarded. Small molecular weight components, including valuable substances such as albumin, are returned to the patient. The advantage of DFPP is that the volume of replacement fluid can be significantly reduced compared to PE. By selecting the optimal pore size model for the plasma component separator, DFPP can be applied to various disorders. The clinical applications of DFPP are reviewed based on recent articles on metabolic disorders, organ transplants, rheumatic disorders, neurological disorders, and dermatologic disorders.

Analysis of organic foulants in the coagulation-microfiltration process for the treatment of Taihu Lake

ABSTRACTThis paper analysed organic foulants in the coagulation-microfiltration process for Taihu Lake treatment. High-performance size-exclusion chromatography (HPSEC) and fluorescence excitation–emission matrices (EEM) were applied to elucidate the influence of characteristics of organics on microfiltration (MF) membrane fouling. Results showed that coagulation pretreatment could extend the operation duration of MF based on the fact that pretreatment could effectively remove macromolecular substances as well as a portion of small molecular weight (MW) organics. The analysis of foulants indicated that organics of strong hydrophobic acids (SHA) and neutral hydrophilic (Neut) fractions (based on hydrophobicity) and medium and small MW components (based on MW distribution) contributed greatly to irreversible fouling. EEM fluorescence analysis of chemical solutions exhibited that aromatic proteins and soluble microbial products were mainly a response to irreversible fouling.

Particulate Component Emission Characteristic from a Diesel Bus with DOC and CDPF

A diesel bus was tested with a China City Bus Cycle (CCBC) on a heavy chassis dynamometer, and the components of the particulate emissions with different after-treatment equipment were investigated. Results showed that OC was less than EC in the particulates of the bus emissions without the use of after-treatment equipment. The organic components were mainly fatty acids (60.9%) and n-alkanes (32.4%), with a few hopanes and PAHs. Fatty acid components were mainly C16:0, C18, C14, and C18:1. The n-alkanes were mainly C18-C24, with C21H44 and C22H46 accounting for the greatest portion. PAH mass was concentrated in medium and small molecular weight components, such as Pyr, FL, and PA. While PAH toxicity was dominated by medium and high molecular weight components, BaP was the most toxic, followed by B(b+k)F, BaA, and IcdP. The total toxicity of the PAHs decreased by 2.7% after DOC treatment and continued to decrease by 89.6%-93.8% after CDPF treatment. After-treatment equipment significantly reduced the OC+EC emissions by 18.9% (DOC) and 70.5%-72.5% (CDPF), but the reduction rate varied from one component to another. The different precious metal loadings of the CDPF did not obviously affect the reduction rate.

Towards quantitative mass spectrometry-based metabolomics in microbial and mammalian systems.

Metabolome analyses are a suite of analytical approaches that enable us to capture changes in the metabolome (small molecular weight components, typically less than 1500 Da) in biological systems. Mass spectrometry (MS) has been widely used for this purpose. The key challenge here is to be able to capture changes in a reproducible and reliant manner that is representative of the events that take place in vivo Typically, the analysis is carried out in vitro, by isolating the system and extracting the metabolome. MS-based approaches enable us to capture metabolomic changes with high sensitivity and resolution. When developing the technique for different biological systems, there are similarities in challenges and differences that are specific to the system under investigation. Here, we review some of the challenges in capturing quantitative changes in the metabolome with MS based approaches, primarily in microbial and mammalian systems.This article is part of the themed issue 'Quantitative mass spectrometry'.

Elasticity Dominated Surface Segregation of Small Molecules in Polymer Mixtures.

We study the phenomenon of migration of the small molecular weight component of a binary polymer mixture to the free surface using mean field and self-consistent field theories. By proposing a free energy functional that incorporates polymer-matrix elasticity explicitly, we compute the migrant volume fraction and show that it decreases significantly as the sample rigidity is increased. A wetting transition, observed for high values of the miscibility parameter can be prevented by increasing the matrix rigidity. Estimated values of the bulk modulus suggest that the effect should be observable experimentally for rubberlike materials. This provides a simple way of controlling surface migration in polymer mixtures and can play an important role in industrial formulations, where surface migration often leads to decreased product functionality.

Comparison between moving bed-membrane bioreactor and conventional membrane bioreactor systems. Part I: membrane fouling

The combination of moving bed biofilm reactor and traditional membrane bioreactor (MBR) shows great potential to be widely used in Liaohe River basin for wastewater treatment. The aim of this research is to compare the bioreactor performance and membrane fouling between integrated fixed-film activated sludge membrane bioreactor (IFAS–MBR) and MBR. Two lab-scale reactors were operated in parallel to treat synthetic municipal wastewater with continuous operation. The results indicated that both systems had the same high removal efficiency of ammonium, while the IFAS–MBR showed a higher ability to remove COD. The trans-membrane pressure in the MBR was higher than that in the IFAS–MBR during the entire operation, due to a higher total modified fouling index of the mixed liquor and the resultant higher membrane fouling potential. The concentrations of extracellular polymeric substances and soluble microbial products were higher in MBR, despite the functional groups were almost similar in two reactors. The conventional MBR had more small molecular weight components (<1 kDa) and soluble microbial metabolites. This seems to cause pore blocking, which directly results in membrane flux declining and membrane resistance rising in the MBR system. In addition, the MBR was characterized by a serious membrane fouling as more dense deposits were observed by scanning electron microscopy. On the contrary, the IFAS–MBR showed a lower membrane fouling tendency during the whole operation.

Biomarkers of NAFLD progression: a lipidomics approach to an epidemic

The spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and cirrhosis. Recognition and timely diagnosis of these different stages, particularly NASH, is important for both potential reversibility and limitation of complications. Liver biopsy remains the clinical standard for definitive diagnosis. Diagnostic tools minimizing the need for invasive procedures or that add information to histologic data are important in novel management strategies for the growing epidemic of NAFLD. We describe an "omics" approach to detecting a reproducible signature of lipid metabolites, aqueous intracellular metabolites, SNPs, and mRNA transcripts in a double-blinded study of patients with different stages of NAFLD that involves profiling liver biopsies, plasma, and urine samples. Using linear discriminant analysis, a panel of 20 plasma metabolites that includes glycerophospholipids, sphingolipids, sterols, and various aqueous small molecular weight components involved in cellular metabolic pathways, can be used to differentiate between NASH and steatosis. This identification of differential biomolecular signatures has the potential to improve clinical diagnosis and facilitate therapeutic intervention of NAFLD.

TLR ligands of ryegrass pollen microbial contaminants enhance Th1 and Th2 responses and decrease induction of Foxp3hi regulatory T cells

Microbial contamination of grass pollens could affect sensitization, subsequent allergic response, and efficacy of allergen-specific immunotherapy. We investigated whether bacterial immunomodulatory substances can direct PBMC responses of allergic and nonatopic subjects against ryegrass pollen (RGP) toward Th1, Th2, or regulatory T (Treg) cells. Aqueous extracts of RGP with high or low LPS were fractionated into large and small molecular weight (MW) components by diafiltration. CFSE-labeled PBMCs from allergic and nonatopic subjects were stimulated with RGP extracts (RGPEs) and analyzed for cytokine secretion and T-cell responses. High LPS RGPE increased IFN-γ(+) Th1 and IL-4(+) Th2 effector cell induction and consistently decreased CD4(+) Foxp3(hi) Treg-cell induction. IL-10-producing T-cell frequency was unaltered, but IL-10 secretion was increased by high LPS RGPE. RGPE-stimulation of TLR-transfected cell lines revealed that high LPS pollen also contained a TLR2-ligand, and both batches a TLR9-ligand. Beta-1,3-glucans were detected in large and small MW fractions and were also T-cell stimulatory. In conclusion, coexposure to allergen and proinflammatory microbial stimuli does not convert an established Th2- into a Th1-response. Instead, proinflammatory responses are exacerbated and Foxp3(hi) Treg-cell induction is decreased. These findings show that adjuvants for specific immunotherapy should enhance Treg cells rather than target immune deviation from Th2 to Th1.

Vapour‐mediated ion activation for enhanced SIMS imaging

The success of time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) imaging is dependent on effective sputtering and ionisation of analytes from the sample surface imaged. Although there have been significant advances in SIMS analysis, thanks to the advent of cluster ion beams, this has largely been in the sputtering process. Ionisation is still largely ineffective, and improvements in this direction would significantly enhance SIMS imaging. We are specifically interested in improving the capabilities of SIMS imaging for detecting metabolites (small molecular weight components of metabolism) in biological cells and tissues. Here, we report a method to enhance the signal intensities of diagnostic ions and improve SIMS imaging of metabolites using a vapour‐mediated ion activation approach. Exposure of a synthetic cocktail of metabolites to ammonia vapour showed a greater than threefold increase in the deprotonated ion signals for some of the metabolites in the cocktail. However, room temperature exposure resulted in changes to the sample morphology, indicating that the sample surface was disrupted. It was possible to increase the ion yield and retain the sample morphology when the treatment was carried out at 4 °C. Application of the methodology to a plant tissue section showed the detection of signals that were not observed in the samples that were not treated. This is a promising approach that can be applied to enhance the detection of diagnostic ions for the ToF‐SIMS analysis of organic and biological samples. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Economic benefits of membrane technology vs. evaporator

European Union food ingredients production operations face operating cost challenges. Ingredient production steps frequently incorporate product recovery steps employing centrifugation, rotary vacuum filtration, evaporation and spray drying demanding high energy inputs. Product and process waste streams contain small molecular weight components that can be concentrated, desalted or, in some applications, fractionated with membrane filtration technology. Substantial capital and operating cost benefits together with selective separations can be derived by use of low energy consumption membrane technology as a complete stand alone process step or in conjunction with evaporation enabling product recovery and water for reuse. Reverse osmosis membrane technology can offer greater than 75% reduction in operating cost when compared with 5 multi-effect evaporation with thermal vapour re-compression process. Mechanical vapour recompression evaporators offer the lowest operating cost, similar to membrane technology, but with a considerably higher capital investment. Many companies which employ evaporation as a standard de-watering step in the manufacture of products such as dairy food ingredients, sugars, sweeteners, beverages, organic acids, renewable source bio-fuels, etc., can potentially reduce their carbon foot print with membrane technology.

Modification of cellulose acetate with oligomeric polycaprolactone by reactive processing: Efficiency, compatibility, and properties

AbstractOligomeric polycaprolactone (oPCL) was used for the modification of cellulose acetate by reactive processing in an internal mixer at 180°C, 50 rpm, 60 min reaction time, and 45 wt % caprolactone (CL) content. The product of the reaction was characterized by several analytical techniques and its mechanical properties were determined by dynamic mechanical thermal analysis and tensile testing. The synthesized oPCL contained small and large molecular weight components. The small molecular weight fraction plasticized cellulose acetate externally and helped fusion. Although composition and structure did not differ considerably from each other when CL monomer or polycaprolactone oligomer was used for modification, the grafting of a few long chains had considerable effect on some properties of the product. The large molecular weight chains attached to CA increased the viscosity of the melt considerably and resulted in larger deformability. oPCL homopolymer is not miscible with cellulose acetate and migrates to the surface of the polymer. Exuded polycaprolactone oligomers crystallize on the surface but can be removed very easily. More intense conditions may favor the grafting of long chains leading to polymers with advantageous properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Deficiency in Microfibril-associated Glycoprotein-1 Leads to Complex Phenotypes in Multiple Organ Systems

Microfibril-associated glycoprotein-1 (MAGP-1) is a small molecular weight component of the fibrillin-rich microfibril. Gene-targeted inactivation of MAGP-1 reveals a complex phenotype that includes increased body weight and size due to excess body fat, an altered wound healing response in bone and skin, and a bleeding diathesis. Elastic tissues rich in MAGP-1-containing microfibrils develop normally and show normal function. The penetrance of MAGP-1-null phenotypes is highly variable and mouse strain-dependent, suggesting the influence of modifier genes. MAGP-1 was found to bind active transforming growth factor-beta (TGF-beta) and BMP-7 with high affinity, suggesting that it may be an important modulator of microfibril-mediated growth factor signaling. Many of the phenotypic traits observed in MAGP-1-deficient mice are consistent with loss of TGF-beta function and are generally opposite those associated with mutations in fibrillin-1 that result in enhanced TGF-beta signaling. Increased body size and fat deposition in MAGP-1-mutant animals are particularly intriguing given the localization of obesity traits in humans to the region on chromosome 1 containing the MAGP-1 gene.

Characterization of tar from sawdust gasified in the pressurized fluidized bed

The paper investigated the features of tar releasing from sawdust gasification in a new designed pressurized fluidized bed. Gel permeation chromatography (GPC) was used to determine the average molecular weight and the molecular weight distribution of sawdust gasified tar, also a photodiode array (PDA) detector was used in parallel to analyze the Ultraviolet (UV) spectra from 210 to 380 nm. At the pressure of 0.5–2.0 MPa and 800 °C, tar had the similar molecular weight distribution and the average molecular weight, the UV spectra absorbed at 254 nm revealed tar of sawdust air gasification at different pressures had aromatic character which increased with the increment of the pressure. By increasing the temperature from 700 to 900 °C, the relative amount of different molecular weight distribution fractions showed that tar contained higher fractions of small molecular weight components. It so gave an indication that tar progressively broke down with the increment of temperature under gasification conditions. The results from the UV absorbed in 254 nm showed a similar aromatic characteristic between 700 and 900 °C, which expressed the presence of larger polynuclear aromatic ring systems, unsaturated conjugated long chain alkyl, heterocyclic structures and alkyl of heteroatom substitutions.