Advancing Simultaneous Extraction and Sequential Single-Particle ICP-MS Analysis for Metallic Nanoparticle Mixtures in Plant Tissues.

Engineered nanoparticles (ENPs) have been increasingly used in agricultural operations, leading to an urgent need for robust methods to analyze co-occurring ENPs in plant tissues. In response, this study advanced the simultaneous extraction of coexisting silver, cerium oxide, and copper oxide ENPs in lettuce shoots and roots using macerozyme R-10 and analyzed them by single-particle inductively coupled plasma-mass spectrometry (ICP-MS). Additionally, the standard stock suspensions of the ENPs were stabilized with citrate, and the long-term stability (up to 5 months) was examined for the first time. The method performance results displayed satisfactory accuracies and precisions and achieved low particle concentration and particle size detection limits. Significantly, the oven drying process was proved not to impact the properties of the ENPs; therefore, oven-dried lettuce tissues were used in this study, which markedly expanded the applicability of this method. This robust methodology provides a timely approach to characterize and quantify multiple coexisting ENPs in plants.

Repeated Low-Level Blast Exposure Alters Urinary and Serum Metabolites.

Repeated exposure to low-level blast overpressures can produce biological changes and clinical sequelae that resemble mild traumatic brain injury (TBI). While recent efforts have revealed several protein biomarkers for axonal injury during repetitive blast exposure, this study aims to explore potential small molecule biomarkers of brain injury during repeated blast exposure. This study evaluated a panel of ten small molecule metabolites involved in neurotransmission, oxidative stress, and energy metabolism in the urine and serum of military personnel (n = 27) conducting breacher training with repeated exposure to low-level blasts. The metabolites were analyzed using HPLC-tandem mass spectrometry, and the Wilcoxon signed-rank test was used for statistical analysis to compare the levels of pre-blast and post-blast exposures. Urinary levels of homovanillic acid (p < 0.0001), linoleic acid (p = 0.0030), glutamate (p = 0.0027), and serum N-acetylaspartic acid (p = 0.0006) were found to be significantly altered following repeated blast exposure. Homovanillic acid concentration decreased continuously with subsequent repeat exposure. These results suggest that repeated low-level blast exposures can produce measurable changes in urine and serum metabolites that may aid in identifying individuals at increased risk of sustaining a TBI. Larger clinical studies are needed to extend the generalizability of these findings.

Optical Oxygen Sensor Patch Printed with Polystyrene Microparticles-based Ink on Flexible Substrate.

Optical oxygen sensors based on photoluminescence quenching have gained increasing attention as a superior method for continuous monitoring of oxygen in a growing number of applications. A simple and low-cost fabrication technique was developed to produce sensor arrays capable of two-dimensional oxygen tension measurement. Sensor patches were printed on polyvinylidene chloride film using an oxygen-sensitive ink cocktail, prepared by immobilizing Pt(II) mesotetra(pentafluorophenyl)porphine (PtTFPP) in monodispersed polystyrene microparticles. The dispersion media of the ink cocktail, high molecular weight polyvinyl pyrrolidone suspended in 50% ethanol (v/v in water), allowed adhesion promotion and compatibility with most common polymeric substrates. Ink phosphorescence intensity was found to vary primarily with fluorophore concentration and to a lesser extent with polystyrene particle size. The sensor performance was investigated as a function of oxygen concentrations employing two different techniques: a multi-frequency phase fluorometer and smart phone-based image acquisition. The printed sensor patch showed fast and repetitive response over 0-21% oxygen concentrations with high linearity (with R2 >0.99) in a Stern-Volmer plot, and sensitivity of I0/I21 >1.55. The optical sensor response on a surface was investigated further using two-dimensional images which were captured and analyzed under different oxygen environment. Printed sensor patch along with imaging read-out technique make an ideal platform for early detection of surface wounds associated with tissue oxygen.

Simultaneous Determination of Eight Urinary Metabolites by HPLC-MS/MS for Noninvasive Assessment of Traumatic Brain Injury.

Traumatic brain injury (TBI) is a serious public health concern for which sensitive and objective diagnostic methods remain lacking. While advances in neuroimaging have improved diagnostic capabilities, the complementary use of molecular biomarkers can provide clinicians with additional insight into the nature and severity of TBI. In this study, a panel of eight metabolites involved in distinct pathophysiological processes related to concussion was quantified using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Specifically, the newly developed method can simultaneously determine urinary concentrations of glutamic acid, homovanillic acid, 5-hydroxyindoleacetic acid, methionine sulfoxide, lactic acid, pyruvic acid, N-acetylaspartic acid, and F2α-isoprostane without intensive sample preparation or preconcentration. The method was systematically validated to assess sensitivity (method detection limits: 1-20 µg/L), accuracy (81-124% spike recoveries in urine), and reproducibility (relative standard deviation: 4-12%). The method was ultimately applied to a small cohort of urine specimens obtained from healthy college student volunteers. The method presented here provides a new technique to facilitate future work aiming to assess the clinical efficacy of these putative biomarkers for noninvasive assessment of TBI.

Cellular oxidative damage is more sensitive to biosynthetic rate than to metabolic rate: A test of the theoretical model on hornworms (Manduca sexta larvae).

We develop a theoretical model from an energetic viewpoint for unraveling the entangled effects of metabolic and biosynthetic rates on oxidative cellular damage accumulation during animal's growth, and test the model by experiments in hornworms. The theoretical consideration suggests that most of the cellular damages caused by the oxidative metabolism can be repaired by the efficient maintenance mechanisms, if the energy required by repair is unlimited. However, during growth a considerable amount of energy is allocated to the biosynthesis, which entails tradeoffs with the requirements of repair. Thus, the model predicts that cellular damage is more influenced by the biosynthetic rate than the metabolic rate. To test the prediction, we induced broad variations in metabolic and biosynthetic rates in hornworms, and assayed the lipid peroxidation and protein carbonyl. We found that the increase in the cellular damage was mainly caused by the increase in biosynthetic rate, and the variations in metabolic rate had negligible effect. The oxidative stress hypothesis of aging suggests that high metabolism leads to high cellular damage and short lifespan. However, some empirical studies showed that varying biosynthetic rate, rather than metabolic rate, changes animal's lifespan. The conflicts between the empirical evidence and the hypothesis are reconciled by this study.

Flue-gas-influenced heavy metal bioaccumulation by the indigenous microalgae Desmodesmus communis LUCC 002.

Desmodesmus communis LUCC 002 was cultivated using flue gas originating from a coal-fired power plant as a carbon dioxide (CO2) source. The flue gas contains various heavy metals. For investigating the fate of flue-gas-introduced metals on the cultivation system, bioaccumulation was measured in the microalgal biomass and milieu. The accumulated biomass was found to contain eight heavy metals: arsenic, chromium, barium, lead, selenium, silver, cadmium, and mercury. High heavy metal accumulations were also found in the control group of algae grown without the addition of flue gas at the same location. Further testing revealed that some of the heavy metals originated from well water used in the cultivation. The flue-gas-influenced bioaccumulation pattern of different heavy metals was observed. The responses of individual heavy metals and the influence of well water microbial flora on the algal growth were investigated, this study showed that hormesis was developed by the D. communis LUCC 002.

Isolation and screening of microalgae from natural habitats in the midwestern United States of America for biomass and biodiesel sources.

Native species of microalgae were isolated from natural water bodies in the Midwestern United States of America and were screened for the ultimate goal of mass cultivation in Missouri and the surrounding states, and for their potential as biomass and biodiesel sources. A number of different nutrient media recipes were utilized to isolate the maximum number of colonies from each field samples. These nutrient recipes were modified in order to optimize the isolation and growth dynamics of specific colonies. All of the isolates were categorized based on the morphological appearance of the culture and the microscopic cellular appearance of the isolated colonies. Isolates included many common green microalgae and cyanobacteria. Lipid content was determined for selected strains that demonstrated relatively quick growth. Scenedesmus sp. that demonstrated the high growth rate, resistance to invasion, and contained sufficient amounts of lipid was investigated for its potential as a sustainable biomass and biodiesel feedstocks.

Heavy metals, hematology, plasma chemistry, and parasites in adult hellbenders (Cryptobranchus alleganiensis).

Ozark (Cryptobranchus alleganiensis bishopi) and eastern hellbenders (C. a. alleganiensis) from seven rivers in Missouri, USA, were collected to investigate essential information on hematology, parasites, and plasma chemistry and levels of select heavy metals (Hg, Pb, Cd, Cr, and Co) in the animals' blood. The body masses of Ozark hellbenders were much smaller than those of eastern hellbenders. Blood parasites were detected in Ozark hellbenders, but not eastern hellbenders. The higher frequency in occurrence of eosinophils in Ozark hellbenders (8.8-16.8%) than in eastern hellbenders (highest at 6.6%) might result from the infection of parasites. Seven of the 18 hematology and plasma parameters (hematocrit, basophils, eosinophils, K, P, Ca, and chloride) showed significant differences between subspecies. The blood levels of heavy metals Co, Hg, and Pb differed significantly between subspecies. Ozark hellbenders had higher blood levels of Co (p<0.001), while blood levels of Hg and Pb were higher in eastern hellbenders. The levels of chromium (Cr) and cadmium (Cd) were not different between subspecies and among rivers. The eastern hellbenders at Niangua River and the Ozark hellbenders at the North Fork of the White River had lower Hg levels compared to eastern and Ozark hellbenders at other sites. All together, our findings provide important baseline information for managing this endangered species.

Comprehensive profiling of isoflavones, phytosterols, tocopherols, minerals, crude protein, lipid, and sugar during soybean (Glycine max) germination.

Isoflavone, phytosterol, tocopherol, mineral, protein, lipid, and sugar contents of soybeans were analyzed during 7-day germination with or without exposure to light. The levels of phytosterols and tocopherols increased significantly during the 3 day germination. Although malonyl glycosides were the predominant forms of isoflavones in soybean seeds, 77% of malonyl daidzin and 30% of malonyl genistin were converted to corresponding daidzin, daidzein, genistin, and genistein during the germination period. Slight decreases in malonal glycidin and malonyl glycidin concentrations were also observed while the total molar concentration of isoflavones remained constant. An increase of approximately 4% in the protein level was accompanied by a 5-6% reduction in the carbohydrate and lipid contents after the 7-day germination. Mineral (Ca, Cr, Fe, Zn Cu, K, Mg, Mn) levels did not vary much during germination, and the presence of light during germination had only a little, if any, effect on the levels of the micro- and macronutrients in soybeans.

Compositional monosaccharide analysis of transgenic corn glycoproteins by HPLC with fluorescence detection and LC-MS with sonic spray ionization.

Transgenic corn offers an attractive, cost-effective means for the large-scale production of engineered glycoproteins suitable for pharmaceutical purposes. A glycoprotein expressed in transgenic corn theoretically should not contain glycans because glycosylation sites have been genetically altered. A sensitive and reliable analytical method is developed to investigate this particular protein for the presence of glycans by monitoring the monosaccharide composition. Identification and quantitation of low-level monosaccharides in the glycoprotein hydrolyzate are accomplished by derivatization prior to high-performance liquid chromatography (HPLC)-fluorescence and liquid chromatography (LC)-sonic spray ionization (SSI)-mass spectrometry (MS) analyses. LC-SSI-MS is used to confirm the results from HPLC-fluorescence analysis and to positively identify the compositional monosaccharides. Glucosamine, glucose, mannose, arabinose, xylose, and sialic acid are found in the transgenic corn derived glycoprotein at less than one moiety per protein, which indicates heterogeneity of the particular glycoprotein. In addition to the compositional analysis of low-level monosaccharides in glycoprotein by HPLC-fluorescence, the utility of SSI for the LC-MS analysis of derivatized monosaccharides is demonstrated in this paper.

Enzymatic synthesis and characterization of l-methionine and 2-hydroxy-4-(methylthio)butanoic acid (HMB) co-oligomers.

Oligomers of l-methionine (Met) and its hydroxy analogue, 2-hydroxy-4-(methylthio)butanoic acid (d,l-HMB) were synthesized with the proteolytic enzyme papain. The Met homooligomers and HMB-Met co-oligomers obtained through the enzymatic reactions were subjected to persulfonation and separated with reverse phase liquid chromatography (RPLC). The separated oligomers were characterized with electrospray ionization-mass spectrometry (ESI-MS). The oligomers were also characterized with matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The results showed that co-oligomers were predominantly composed of 4-8 Met residues and one HMB residue. The data also suggest that in the co-oligomers, HMB is attached at the N-terminal end of the oligopeptide chain.