Neogene biomarker record of vegetation change in eastern Africa.

The evolution of C4 grassland ecosystems in eastern Africa has been intensely studied because of the potential influence of vegetation on mammalian evolution, including that of our own lineage, hominins. Although a handful of sparse vegetation records exists from middle and early Miocene terrestrial fossil sites, there is no comprehensive record of vegetation through the Neogene. Here we present a vegetation record spanning the Neogene and Quaternary Periods that documents the appearance and subsequent expansion of C4 grasslands in eastern Africa. Carbon isotope ratios from terrestrial plant wax biomarkers deposited in marine sediments indicate constant C3 vegetation from ∼24 Ma to 10 Ma, when C4 grasses first appeared. From this time forward, C4 vegetation increases monotonically to present, with a coherent signal between marine core sites located in the Somali Basin and the Red Sea. The response of mammalian herbivores to the appearance of C4 grasses at 10 Ma is immediate, as evidenced from existing records of mammalian diets from isotopic analyses of tooth enamel. The expansion of C4 vegetation in eastern Africa is broadly mirrored by increasing proportions of C4-based foods in hominin diets, beginning at 3.8 Ma in Australopithecus and, slightly later, Kenyanthropus This continues into the late Pleistocene in Paranthropus, whereas Homo maintains a flexible diet. The biomarker vegetation record suggests the increase in open, C4 grassland ecosystems over the last 10 Ma may have operated as a selection pressure for traits and behaviors in Homo such as bipedalism, flexible diets, and complex social structure.

Newly Developed Neutralized pH Icodextrin Dialysis Fluid: Nonclinical Evaluation.

A two-compartment system (NICOPELIQ; NICO, Terumo Co., Tokyo, Japan) has recently been developed to neutralize icodextrin peritoneal dialysis fluid (PDF). In this study, a nonclinical evaluation of NICO was carried out to evaluate biocompatibility as well as water transport ability. Glucose degradation products (GDPs) in the icodextrin PDFs were analyzed via high-performance liquid chromatography (HPLC). The cell viability of human peritoneal mesothelial cells derived from peritoneal dialysis effluent (PDE-HPMCs) was evaluated as well as the amount of lactate dehydrogenase (LDH) released after exposure to different PDFs (NICO and EXTRANEAL [EX, Baxter Healthcare Corp., Chicago, IL, USA]) and neutralized pH glucose PDF MIDPELIQ 250 (M250, Terumo). The water transport ability of NICO, EX, and M250 was tested using dialysis tube membranes with various pore sizes: 1, 2, 6-8, and 12-16 kDa. Although cell viability decreased by 30% after 30 min exposure to NICO, it was maintained for 6 h while a significant decrease was observed after 6 h exposure to EX. However, following adjustment of the pH to the same pre-exposure pH value, there was no significant difference in cell viability within the same pH group despite a doubling of the difference in the total amount of GDPs (44.6 ± 8.6 µM in NICO and 91.9 ± 9.5 µM in EX, respectively). In contrast, a significant decrease in cell viability was observed when the pH decreased to less than pH 6. Levels of released LDH, a cytotoxic marker, were within 5% after a 6-h exposure of NICO to PDE-HPMCs. There was no significant difference in water transport ability represented as overall osmotic gradients between NICO and EX. In conclusion, neutralization of icodextrin PDF is beneficial for maintaining cell viability and minimizing LDH release while water transport ability is comparable to the conventional icodextrin PDF.

Ambient mass spectrometry imaging of food natural products by angled direct analysis in real time high-resolution mass spectrometry.

Direct surface analysis in ambient conditions provides information on the position and chemical composition of an object at the time of investigation. An angled sampling probe is developed in this work for direct analysis in real time (DART) ionization high-resolution mass spectrometry. The DART ion source and the interface were modified for improved surface resolution, increased ion transfer efficiency, as well as enabling two-dimensional surface scanning. The angled probe DART-MS system was used for investigating a variety of food samples including fruit peels, ginseng root, plant leaves and sections of radish. Abundant signals and distinct chemical profiles are obtained in seconds, and spatial distribution of different molecules across the sample surfaces can be observed. In addition, the developed system can quickly identify the chemical changes when the surfaces were treated. The method is capable of directly evaluating food sample surfaces with different shapes, hardness, and conditions, without any sample pretreatments.

[Molecular Signatures of Dissolved Organic Matter in the Paihe River and Its Tributaries].

Dissolved organic matter (DOM) is an abundant and critical component of aquatic ecosystems, participating in many physicochemical and biogeochemical processes. The Paihe River is the only inflow river in the Jianghuai section of "Yangtze-Huaihe water diversion" clear water gallery project; however, its DOM molecular composition information and characteristics are still unclear. In this study, the molecular characterization of DOM in the Paihe River and Guangming Dayan River was determined using Orbitrap mass spectrometry. The Pearson's correlation and principal component analysis (PCA) were used to study the relationship between molecular composition information, characteristics, and sources of DOM in two rivers. The results showed that the molecular weight and oxygen content of DOM molecules in the Paihe River were relatively low; the molecular weight, aromaticity, and unsaturation of DOM molecules in the Guangming Dayan River were relatively high. From the element composition and compound composition of the two rivers' DOM, both rivers were mainly composed of CHO-compounds, lignin, and tannins derived from land plants, which indicates that both rivers were severely affected by terrestrial input. There were high percentages of CHOS, protein, and lipid compounds of DOM in the Paihe River. According to the results of the Pearson's correlation and PCA analyses, the DOM molecules of the Paihe River were also influenced by wastewater from sewage treatment plants, urbanization processes, and microbial activity. Molecular composition information and characteristics of DOM can provide a detailed reference to improve the theoretical support for the Paihe River clear water gallery project.

Importance of Locations of Iron Ions to Elicit Cytotoxicity Induced by a Fenton-Type Reaction.

The impact of the site of the Fenton reaction, i.e., hydroxyl radical (•OH) generation, on cytotoxicity was investigated by estimating cell lethality in rat thymocytes. Cells were incubated with ferrous sulfate (FeSO4) and hydrogen peroxide (H2O2), or pre-incubated with FeSO4 and then H2O2 was added after medium was replaced to remove iron ions or after the medium was not replaced. Cell lethality in rat thymocytes was estimated by measuring cell sizes using flow cytometry. High extracellular concentrations of FeSO4 exerted protective effects against H2O2-induced cell death instead of enhancing cell lethality. The pre-incubation of cells with FeSO4 enhanced cell lethality induced by H2O2, whereas a pre-incubation with a high concentration of FeSO4 exerted protective effects. FeSO4 distributed extracellularly or on the surface of cells neutralized H2O2 outside cells. Cytotoxicity was only enhanced when the Fenton reaction, i.e., the generation of •OH, occurred inside cells. An assessment of plasmid DNA breakage showed that •OH induced by the Fenton reaction system did not break DNA. Therefore, the main target of intracellularly generated •OH does not appear to be DNA.

Mechanical properties of a polymethyl methacrylate block for CAD/CAM dentures.

This study compared the mechanical properties and molecular distribution of a polymethyl methacrylate (PMMA) block (Dry) with specimens that were fabricated by a conventional method and cured in a wet environment (Control). Two specimen types were fabricated with heat-curing denture base resin. Dry specimens were polymerized at high pressure and in a dry system, while Control specimens were polymerized with a heat-curing method, in accordance with the manufacturer's recommended procedures. Specimens from each group were evaluated for three-point bending, water sorption and solubility, and color change, and by gel permeation chromatography (GPC). Mean values for the flexural strengths and moduli of the Dry specimens were significantly higher than those of the Control specimens (P > 0.05). Water sorption and discoloration values of the Dry group were significantly lower than those of the Control group. Mean weight-average molecular weights of the Dry group were higher than those of the Control group. As compared with the conventional method, the present method of fabricating PMMA blocks under high pressure yields superior mechanical properties for the denture base.

Effectiveness of the rapid test of polar compounds in frying oils as a function of environmental and compositional variables under restaurant conditions.

Effect of fried food, oil type, moisture, fatty acid and molecular distribution on the effectiveness of rapid test of Total Polar Compounds (TPC) in frying oil based on dielectric constant was explored. Effects of all factors were compared and found to be significant (P < 0.05). Throughout the life cycle of frying oil, its rapid results were correlated well with those of conventional chromatography (Y = 0.7625X + 3.681, R2 = 0.8734). But the discrepancy was found within selected TPC ranges of 0%-10% and 20%-30%. According to the definition of TPC, three potential reasons for the high TPC values of fresh oils were discussed. For the deteriorated oils, the triglyceride dimers, mono-unsaturated and di-unsaturated fatty acids were found to be the main compositional factors by stepwise multivariate regression analysis. Pieces of advice about the operation guideline, internal control indices, calibration, reference oil, sensor, and detection range were proposed for instrument users and producers.

Effect of ultrasonic-ionic liquid pretreatment on the hydrolysis degree and antigenicity of enzymatic hydrolysates from whey protein.

With the aim to reduce the antigenicity of whey protein hydrolysate in milk, the pretreatment method of coupling ultrasonic and ionic liquid (US-IL) and further enzymatic treatments were studied. Papain and alcalase were found to be suitable for ultrasonic-ionic liquid pretreatment. After ultrasound-ionic liquid treatment, the antigenic decline rates of ALA and BLG upon alcalase hydrolysis were 82.82% and 88.01%, and that of the papain hydrolysis was 81.87% and 88.46%, respectively. Upon ultrasonic-ionic liquid pretreatment, the molecular weight of whey protein did not change significantly, but the small molecular weight proportion of components in the enzymatic hydrolysate obviously increased. The findings showed that combining with US-IL pretreatment for further protease hydrolysis of whey proteins, the hydrolysate can be used in order to produce hypoallergenic bovine whey proteins.

Recent advances of ambient mass spectrometry imaging for biological tissues: A review.

Ambient mass spectrometry imaging (AMSI) is a molecular imaging technique developed in recent years for in situ and real time visualization of the distribution of chemical compounds in biological tissues without the need of labeling or staining. With the development for more than one decade, AMSI becomes a powerful molecular imaging technique in variousfields such as forensics, metabolomics, cancer diagnosis, and drug monitoring. In this review, we describe the recent advances of AMSI for imaging biological tissues in details. Three types of AMSI techniques based on different ionization mechanisms and analytical strategies are summarized, i.e., direct desorption/ionization of analytes for AMSI, desorption and then ionization of analytes for AMSI, and extraction of analytes for AMSI, and the features of them are presented from the aspects of tissue origin, target image molecule, and spatial resolution among others. In addition, future development directions for AMSI are discussed.

Effect of solid-state fermentation on proximate composition, anti-nutritional factor, microbiological and functional properties of lupin flour.

The effects of solid-state fermentation (SSF) with Aspergillus sojae, Aspergillus ficuum and their co-cultures on proximate composition, anti-nutritional factor, microbiological and functional properties of lupin flour (LF) were investigated. Fibre fractions, in vitro enzyme protein digestion (IVPD), total phenolic contents, protein molecular distribution and colour attributes were also evaluated. Samples differed in their proximate composition except ash and fibre contents. The microbiological counts of the fermented LFs were generally higher (p < 0.05) than that of the unfermented LF. Phytic acid content and IVPD decreased (p < 0.05) in the fermented LFs. Also, the fermented LFs showed decreased (p < 0.05) water absorption capacity but increased swelling capacity. In addition, fermented LFs demonstrated reduction in colour attributes. Thus, the study indicated that SSF using Aspergillus sojae and Aspergillus ficuum can influence the physical, chemical and functional properties of LF. LF has great potentials in developing new nutritious food products and feed formulations when subjected to SSF.

Asymmetric RNA Distribution among Cells and Their Secreted Exosomes: Biomedical Meaning and Considerations on Diagnostic Applications.

Over the past few years, exosomes and their RNA cargo have been extensively studied because of the fascinating biological roles they play in cell-to-cell communication, including the signal exchange among cancer, stromal, and immune cells, leading to modifications of tumor microenvironment. RNAs, especially miRNAs, stored within exosomes, seem to be among the main determinants of such signaling: their sorting into exosomes appears to be cell-specific and related to cellular physiopathology. Accordingly, the identification of exosomal miRNAs in body fluids from pathological patients has become one of the most promising activity in the field of biomarker discovery. Several analyses on the qualitative and quantitative distribution of RNAs between cells and their secreted exosomes have given rise to questions on whether and how accurately exosomal RNAs would represent the transcriptomic snapshot of the physiological and pathological status of secreting cells. Although the exact molecular mechanisms of sorting remain quite elusive, many papers have reported an evident asymmetric quantitative distribution of RNAs between source cells and their exosomes. This phenomenon could depend both on passive and active sorting mechanisms related to: (a) RNA turnover; (b) maintaining the cytoplasmic miRNA:target equilibrium; (c) removal of RNAs not critical or even detrimental for normal or diseased cells. These observations represent very critical issues in the exploitation of exosomal miRNAs as cancer biomarkers. In this review, we will discuss how much the exosomal and corresponding donor cell transcriptomes match each other, to better understand the actual reliability of exosomal RNA molecules as pathological biomarkers reflecting a diseased status of the cells.

Molecular weight distribution and fermentation of mechanically pre-treated konjac enzymatic hydrolysates.

There is interest in novel fibers as potential prebiotics for new and reformulated food products. Two konjac glucomannan (KGM) hydrolysates were developed by enzymatic hydrolysis with (KGMH I) or without (KGMH II) mechanical shear pre-treatment. These were characterized and evaluated as fermentation substrates using five lactobacilli and three bifidobacteria. Enzymatic treatment of native KGM reduced the average molecular weights of supernatant and pellet by ∼3-fold. Additional mechanical shear pre-treatment further reduced supernatant and pellet molecular weights by 5% and 35%, respectively. We postulated that pulverized and depolymerized short-chain KGM would better promote the growth of lactobacilli and bifidobacteria. Most lactobacilli fermented KGM hydrolysates. Lactobacillus acidophilus and Lactobacillus plantarum fermented KGMH I and II better than they fermented inulin. Overall, bifidobacteria were not strong fermenters of KGM hydrolysates. Both pulverization and enzymatic depolymerization significantly affected KGM molecular weight, suggesting that human gastrointestinal bacteria can utilize KGM hydrolysates with reduced weights.

Rheological properties, molecular distribution, and microstructure of Fortunella margarita (Lour.) swingle polysaccharides.

Fortunella margarita polysaccharides (FMPS) are one of the main bioactive components of F. margarita. The activity is related to their rheological properties and structure. The objective of this study was to investigate the relationship between rheological properties, molecular distribution, and microstructure of crude FMPS (C-FMPS) and purified FMPS (P-FMPS). The results showed that both of solutions were shear-thinning pseudoplastic fluids with flow properties in line with the Power Law model. The pseudoplasticity of P-FMPS was stronger compared to C-FMPS. Additionally, the molecular weight and polydispersity of P-FMPS were greater, whereas the molecular radius was less compared to C-FMPS. The surface of C-FMPS was rough and dense whereas P-FMPS displayed a smooth network structure by environment scanning electron microscopy. According to confocal laser scanning microscopy, C-FMPS dispersed in the medium without connected network, whereas the network of P-FMPS was unevenly distributed in the medium and the shape was compact and smooth. The molecular distribution and microstructure of P-FMPS were attributed to the purification process while rearrangement and aggregation of polysaccharide molecules took place, which resulted in the significant difference of rheological properties between C-FMPS and P-FMPS.

Molecular distribution of amino acid substitutions on neuraminidase from the 2009 (H1N1) human influenza pandemic virus.

The pandemic influenza AH1N1 (2009) caused an outbreak of human infection that spread to the world. Neuraminidase (NA) is an antigenic surface glycoprotein, which is essential to the influenza infection process, and is the target of anti-flu drugs oseltamivir and zanamivir. Currently, NA inhibitors are the pillar pharmacological strategy against seasonal and global influenza. Although mutations observed after NA-inhibitor treatment are characterized by changes in conserved amino acids of the enzyme catalytic site, it is possible that specific amino acid substitutions (AASs) distant from the active site such as H274Y, could confer oseltamivir or zanamivir resistance. To better understand the molecular distribution pattern of NA AASs, we analyzed NA AASs from all available reported pandemic AH1N1 NA sequences, including those reported from America, Africa, Asia, Europe, Oceania, and specifically from Mexico. The molecular distributions of the AASs were obtained at the secondary structure domain level for both the active and catalytic sites, and compared between geographic regions. Our results showed that NA AASs from America, Asia, Europe, Oceania and Mexico followed similar molecular distribution patterns. The compiled data of this study showed that highly conserved amino acids from the NA active site and catalytic site are indeed being affected by mutations. The reported NA AASs follow a similar molecular distribution pattern worldwide. Although most AASs are distributed distantly from the active site, this study shows the emergence of mutations affecting the previously conserved active and catalytic site. A significant number of unique AASs were reported simultaneously on different continents.

Intermolecular interaction of phosphatidylinositol with the lipid raft molecules sphingomyelin and cholesterol.

Diacylphosphatidylinositol (PI) is the starting reactant in the process of phosphatidylinositide-related signal transduction mediated through the lipid raft domain. We investigated intermolecular interactions of PI with major raft components, sphingomyelin (SM) and cholesterol (Chol), using surface pressure-molecular area (π-A) isotherm measurements. The classical mean molecular area versus composition plot showed that the measured mean molecular areas are smaller in PI/Chol mixed monolayers and larger in PI/SM mixed monolayers than those calculated on the basis of the ideal additivity. These results indicate that PI interacts attractively with Chol and repulsively with SM. In addition, we energetically evaluated the interaction of PI with SM/Chol mixtures and found that the mixing energy of PI/SM/Chol ternary monolayers decreased as the molar ratio of Chol to SM increased. In order to quantitatively analyze the distribution of PI we calculated the chemical potentials of mixing of PI into the SM/Chol mixed monolayer and into the dioleoylphosphatidylcholine (DOPC) monolayer, which was used as a model for the fluid matrix, on the basis of partial molecular area analysis. Analysis using the chemical potential of mixing of PI suggested that partition of PI molecules between these two monolayers can be changed by a factor of about 1.7 in response to change in Chol molar fraction in the SM/Chol mixed monolayer from 0.3 to 0.6 when the concentration of PI in the DOPC monolayer is kept constant at 7 mol%.