Prevalence of Rh, Kell, Kidd, Duffy, and MNS antigens in the Hispanic donor population of South Texas.

As population diversity in the United States expands, understanding antigen prevalence by ethnic group is essential. Differences in antigen prevalence among ethnicities have caused increased alloimmunization in chronically transfused patients. Recognizing these differences in patients and donors can reduce the risk of patients developing alloantibodies. Also, determining the antigen prevalence by ethnicity will improve the ability of blood centers to have compatible blood available. Thus far, there has not been significant published data on antigen prevalence of the U.S. Hispanic population. A retrospective cross-sectional study was performed to determine the prevalence of red blood cell (RBC) antigens, as determined by human erythrocyte antigen genotyping, in South Texas Hispanic blood donors. A total of 3455 donors, seen from 1 January 2015 to 31 May 2020, were included in the study. These donors met the inclusion criteria of self-selecting Hispanic ethnicity and successfully donating a RBC component. The antigen results for each included donor were entered into a data collection spreadsheet. The prevalence of each antigen was calculated. A binomial test was performed to determine if the observed results are statistically different as compared with the published prevalence of antigens in white and black populations. After statistical analysis, the p value for most antigens was statistically significant (p < 0.05). The Kidd blood group antigens were the only major antigens that did not show a significant difference. Cohen's h showed a large effect size for most antigens when compared with those of the black population and a small to medium effect size when compared with those of the white population. For most blood groups antigens, their prevalence in Hispanic donors was significantly different than that published for both white and black populations.

Lymphoid susceptibility to the Aggregatibacter actinomycetemcomitans cytolethal distending toxin is dependent upon baseline levels of the signaling lipid, phosphatidylinositol-3,4,5-triphosphate.

The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces G2 arrest and apoptosis in lymphocytes and other cell types. We have shown that the active subunit, CdtB, exhibits phosphatidylinositol-3,4,5-triphosphate (PIP3) phosphatase activity and depletes lymphoid cells of PIP3. Hence we propose that Cdt toxicity results from depletion of this signaling lipid and perturbation of phosphatidylinositol-3-kinase (PI-3K)/PIP3/Akt signaling. We have now focused on the relationship between cell susceptibility to CdtB and differences in the status of baseline PIP3 levels. Our studies demonstrate that the baseline level of PIP3, and likely the dependence of cells on steady-state activity of the PI-3K signaling pathway for growth and survival, influence cell susceptibility to the toxic effects of Cdt. Jurkat cells with known defects in both PIP3 degradative enzymes, PTEN and SHIP1, not only contain high baseline levels of PIP3, pAkt, and pGSK3ß, but also exhibit high sensitivity to Cdt. In contrast, HUT78 cells, with no known defects in this pathway, contain low levels of PIP3, pAkt, and pGSK3ß and likely minimal dependence on the PI-3K signaling pathway for growth and survival, and exhibit reduced susceptibility to Cdt. These differences in susceptibility to Cdt cannot be explained by differential toxin binding or internalization of the active subunit. Indeed, we now demonstrate that Jurkat and HUT78 cells bind toxin at comparable levels and internalize relatively equal amounts of CdtB. The relevance of these observations to the mode of action of Cdt and its potential role as a virulence factor is discussed.

Abiotic and biotic dynamics during the initial stages of high solids switchgrass degradation.

An understanding of the underlying dynamics of how biotic variables drive changes in abiotic parameters in the early stages of biomass biodegradation is essential for better control of the process. Probe hybridization was used to quantitatively study the growth of bacteria, yeast and fungi for three levels of initial moisture content (60, 65 and 75% MC) over a period of 64 h. Changes in abiotic parameters were also documented. By 64 h, samples were significantly differentiated both in temporal and spatial dimension, proving that considerable changes had occurred in these initial stages. Maximum carbon (C) conversion occurred in the 75% MC reactor at a peak value of 49%, with 40% and 37% in the 65 and 60% MC reactors, respectively. Higher temperature, higher pH, higher rates of O2 consumption and CO2 evolution were also observed in the highest moisture reactor; suggesting that of the three MCs studied, 75% MC was the optimal one for the process. MC during the process also proved to be important because it greatly influenced variation in the spatial dimension, further underscoring the importance of characterizing changes with bed height. Most importantly, we were able to positively correlate the rate of substrate degradation with bacterial biomass levels and highlight the critical role of bacteria in biological decomposition.

Gene expression levels as endophenotypes in genome-wide association studies of Alzheimer disease.

BACKGROUND: Late-onset Alzheimer disease (LOAD) is a common disorder with a substantial genetic component. We postulate that many disease susceptibility variants act by altering gene expression levels. METHODS: We measured messenger RNA (mRNA) expression levels of 12 LOAD candidate genes in the cerebella of 200 subjects with LOAD. Using the genotypes from our LOAD genome-wide association study for the cis-single nucleotide polymorphisms (SNPs) (n = 619) of these 12 LOAD candidate genes, we tested for associations with expression levels as endophenotypes. The strongest expression cis-SNP was tested for AD association in 7 independent case-control series (2,280 AD and 2,396 controls). RESULTS: We identified 3 SNPs that associated significantly with IDE (insulin degrading enzyme) expression levels. A single copy of the minor allele for each significant SNP was associated with approximately twofold higher IDE expression levels. The most significant SNP, rs7910977, is 4.2 kb beyond the 3' end of IDE. The association observed with this SNP was significant even at the genome-wide level (p = 2.7 x 10(-8)). Furthermore, the minor allele of rs7910977 associated significantly (p = 0.0046) with reduced LOAD risk (OR = 0.81 with a 95% CI of 0.70-0.94), as expected biologically from its association with elevated IDE expression. CONCLUSIONS: These results provide strong evidence that IDE is a late-onset Alzheimer disease (LOAD) gene with variants that modify risk of LOAD by influencing IDE expression. They also suggest that the use of expression levels as endophenotypes in genome-wide association studies may provide a powerful approach for the identification of disease susceptibility alleles.

Development and analysis of oxygen-sensing probes for in situ monitoring of unsaturated solid-state biodegradation processes.

Oxygen (O2) sensors have been developed for in situ measurement of O2 in high-solids degradation processes. The O2 sensor has been shown to withstand the corrosive environment of the biodegradation process with high humidity and temperatures exceeding 60 degrees C. Calibration tests prior to and after in situ operation showed the sensor to perform accurately and reproducibly after 71 days of in situ operation. A linear relationship between O2-sensor output and water vapor pressure was confirmed through calibration experiments. To compensate for the effect of water vapor pressure on O2-sensor measurements, O2 concentration was expressed on a dry air basis using the confirmed linear relationship. In situ O2-sensor output expressed on a dry air basis was found to follow trends of gas samples analyzed by gas chromatography with good agreement.

Engineering cellulase mixtures by varying the mole fraction of Thermomonospora fusca E5 and E3, Trichoderma reesei CBHI, and Caldocellum saccharolyticum beta-glucosidase.

In this study, different mole fractions of pure Thermomonospora fusca E(5) and E(3), plus Trichoderma reesei CBHI were studied for reducing sugar production at 2 h, degree of synergism, and cellulose binding. In addition, the effects of introducing the Caldocellum saccharolyticum beta-glucosidase into this cellulase system were investigated. The cellulases used were purified to homogeneity. Avicel PH 102 (4% w/w solution in 0.05 sodium acetate pH 5.5 buffer) was the substrate. Reactions were run at 50 degrees C for 2 h using total cellulase concentrations of 8.3 or 12.2 microM. A bimixture of T. fusca E(3) and T. reesei CBHI was very effective in hydrolyzing microcrystalline cellulose (9.1% conversion). The addition of endoglucanase E(5) to the mixture only increased conversion to 9.8%. However, when both E(5) and beta-glucosidase were added, conversion increased to 14%. It was also observed that increasing total cellulase concentration beyond 8.3 muM did little to increase percent conversion of cellulose into glucose. The results of the binding studies indicate no competition for binding sites between the endo- and exocellulases.

Activity studies of eight purified cellulases: Specificity, synergism, and binding domain effects.

The activities of six purified Thermomonospora fusca cellulases and Trichoderma reesei CBHI and CBHII were determined on filter paper, swollen cellulose, and CMC. A simple method to measure the soluble and insoluble reducing sugar products from the hydrolysis of filter paper was found to effectively distinguish between exocellulases and endocellulases. Endocellulases produced 34% to 50% insoluble reducing sugar and exocellulases produced less than 8% insoluble reducing sugar. The ability of a wide variety of mixtures of these cellulases to digest 5.2% of a filter paper disc in 16 h was measured quantitatively. The specific activities of the mixtures varied from 0.41 to 16.31 micromol cellobiose per minute per micromole enzyme. The degree of synergism ranged from 0.4 to 7.8. T. reesei CBHII and T. fusca E3 were found to be functionally equivalent in mixtures. The catalytic domains (cd) of T. fusca endocellulases E2 and E5 were purified and found to retain 93% and 100% of their CMC activity, respectively, but neither cd protein could digest filter paper to 5.2%. When E2cd and E5cd were substituted in synergistic mixtures for the native proteins, the mixtures containing E2cd retained 60%, and those containing E5cd retained 94% of the original activity. Addition of a beta-glucosidase was found to double the activity of the best synergistic mixture. Addition of CBHI to T. fusca crude cellulase increased its activity on filter paper 1.7-fold.

Fragmentation of cellulose by the major Thermomonospora fusca cellulases, Trichoderma reesei CBHI, and their mixtures.

In this study, the fragmentation activities of Thermomonospora fusca cellulases E(2), E(3), E(5), Trichoderma reesei CBHI, and their mixtures were measured to study synergism in fragmentation. Fragmentation studies revealed that only two pure cellulases, T. fusca E(2) and E(5) had significant fragmentation activity. T. fusca E(3) shows strong synergism in fragmentation both in the production of reducing sugars and in fragmentation with both T. fusca endoglucananses and with T. reesei CBHI. Most mixtures containing CBHI produced higher rates of fragmentation than comparable mixtures containing E(3). The highest rate and extent of reducing sugar formation and the highest fragmentation activity were obtained with a mixture of E(2), E(3), and CBHI.

Solute exclusion from cellulose in packed columns: experimental investigation and pore volume measurements.

A packed column approach was used in this investigation to determine pore volume and surface area distributions of several celluloses. Specific surface areas for Avicel PH 102, Solka Floc BW 300, and two size fractions of corn cobs that have been pretreated to remove lignin and hemicellulose were measured using this technique. In addition to measuring pore volume and specific surface area, the molecular diameters of several PEGs (polyethylene glycol) were estimated using viscosity measurements. Also, the influence of cellulose particle size, molecular diameter of PEGs, and PEG solution velocity on dispersion and tailing were investigated. Molecular diameter estimates from this investigation were 30%-35% lower than those reported in the literature. This discrepancy is due to earlier investigators using an inappropriate relationship for estimating molecular diameter from viscosity measurements. The precision of the column approach to solute exclusion was higher than that obtained by investigators using a batch approach. Dispersion increased with increasing particle size. Tailing of the elution curve was increased with increasing solute molecular diameter and elution rate. For a cellulase with a molecular diameter of 5.1 nm, estimated specific surface area ranged from 7.2 to 10.5 m(2) g(-1).

Solute exclusion from cellulose in packed columns: process modeling and analysis.

In this investigation, process modeling and analysis were used to explore the behavior of solute exclusion from cellulose in packed columns. The study focused on modeling the effects of dispersion, mass transport, and pore diffusion. Three mathematical models were used to predict the behavior of the columns: an equilibrium model, a mass transfer model, and a combined mass transfer and pore diffusion model. Computer implementations of these models were tested against experimental conditions where cellulose particle size and solution velocity were used to either amplify or minimize dispersion or skewness in the elution curves. For small cellulose particles (200-300 mesh), all three models accurately predicted the shape of the elution curve and the particle porosity. For larger particles (45-60 mesh), the mass transfer model and the combined mass and pore diffusion model best represented the behavior of the column. At high solution velocities (0.63 cm(3) min(-1)) and large particles, only the combined mass transfer and pore diffusion model accurately represent the column behavior. Sensitivity analysis revealed that the mass transfer coefficient had little effect on the elution curves for the range of values (10(-6)-10(-3) cm s(-1)) calculated from the experimental data. The combined mass transfer and pore diffusion model presented in this article can be used to design solute exclusion measurement experiments for the larger cellulose particles found in a commercial cellulose-to-ethanol plant.

Measurement of Net Fluxes of Ammonium and Nitrate at the Surface of Barley Roots Using Ion-Selective Microelectrodes : II. Patterns of Uptake Along the Root Axis and Evaluation of the Microelectrode Flux Estimation Technique.

Net fluxes of NH(4) (+) and NO(3) (-) into roots of 7-day-old barley (Hordeum vulgare L. cv Prato) seedlings varied both with position along the root axis and with time. These variations were not consistent between replicate plants; different roots showed unique temporal and spatial patterns of uptake. Axial scans of NH(4) (+) and NO(3) (-) net fluxes were conducted along the apical 7 centimeters of seminal roots of intact barley seedlings in solution culture using ion-selective microelectrodes in the unstirred layer immediately external to the root surface. Theoretically derived relationships between uptake and concentration gradients, combined with experimental observations of the conditions existing in our experimental system, permitted evaluation of the contribution of bulk water flow to ion movement in the unstirred layer, as well as a measure of the spatial resolution of the microelectrode flux estimation technique. Finally, a method was adopted to assess the accuracy of this technique.