Structural and functional analogy between pneumolysin and proaerolysin

Pneumolysin and proaerolysin are bacterial toxins that form pores in host cells by oligomerization. We propose that they may have similar structures despite a poor sequence identity. The crystal structure of proaerolysin reveals a protein composed of four domains, arranged in the shape of an elongated comma. Electron microscopy of the pneumolysin monomer shows a similar arrangement of domains. The sequence of pneumolysin recognizes the template of proaerolysin from a library of protein folds. A three-dimensional model of pneumolysin has been constructed by the comparative approach using the structure of proaerolysin. This model, together with results on the activity of site- specific mutants and the positions of antigenic sites, has been used to propose functional roles of individual domains.      

Temperature stability range of the binary MoC phase

The MoC phase with the WC structure was prepared by a novel synthetic route that involved the stoichiometric disproportionation of a high-temperature phase, Mo ₃ C ₂ , to MoC and M0 ₂ C at 1000 °C. MoC was found to be thermodynamically stable at temperatures below 1080 °C. From consideration of equilibrium and calorimetric data, the thermodynamic properties of MoC can be established as S ₂₉₈ ⁰/R = 4.41(0.3) andΔH ₂₉₈ ⁰/R = -3430(800)K, Paper presented at the Calorimetry Conference, Asilomar, California.     

Determination of the Fe2+/Fe3+ Ratio in Nuclear Waste Glasses

The Fe²⁺/Fe³⁺ ratios of 47 simulated nuclear waste glass samples with ratios varying from 0.01 (oxidized) to 1.6 (reduced) were determined by wet-chemical and Mössbauer spectral analyses. The wet-chemical method involved the spectrophotometric determination of Fe²⁺ and total iron using remote spectroscopy with fiber optic chemical sensing. Interferences from other species present in these glasses were examined and alternative analytical techniques were investigated. Results of wet-chemical and Mössbauer spectral analysis were comparable; however, the wet-chemical method is probably preferable for the analysis of highly radioactive glasses until such glasses have been shown to have satisfactory Mössbauer spectra.     

Multiple Na,K-ATPase Subunits Colocalize in the Brush Border of Mouse Choroid Plexus Epithelial Cells

(1) Background: The unusual accumulation of Na,K-ATPase complexes in the brush border membrane of choroid plexus epithelial cells have intrigued researchers for decades. However, the full range of the expressed Na,K-ATPase subunits and their relation to the microvillus cytoskeleton remains unknown. (2) Methods: RT-PCR analysis, co-immunoprecipitation, native PAGE, mass spectrometry, and differential centrifugation were combined with high-resolution immunofluorescence histochemistry, proximity ligase assays, and stimulated emission depletion (STED) microscopy on mouse choroid plexus cells or tissues in order to resolve these issues. (3) Results: The choroid plexus epithelium expresses Na,K-ATPase subunits α1, α2, β1, β2, β3, and phospholemman. The α1, α2, β1, and β2, subunits are all localized to the brush border membrane, where they appear to form a complex. The ATPase complexes may stabilize in the brush border membrane via anchoring to microvillar actin indirectly through ankyrin-3 or directly via other co-precipitated proteins. Aquaporin 1 (AQP1) may form part of the proposed multi-protein complexes in contrast to another membrane protein, the Na-K-2Cl cotransporter 1 (NKCC1). NKCC1 expression seems necessary for full brush border membrane accumulation of the Na,K-ATPase in the choroid plexus. (4) Conclusion: A multitude of Na,K-ATPase subunits form molecular complexes in the choroid plexus brush border, which may bind to the cytoskeleton by various alternative actin binding proteins.     

Quality changes in beef complexus, serratus ventralis, vastus lateralis, vastus medialis, and longissimus dorsi muscles enhanced prior to aging

ABSTRACT:  Beef complexus (chuck), serratus ventralis (chuck), vastus lateralis (round), vatsus medialis (round), and longissimus dorsi (loin) muscles were enhanced (0.3% salt, 0.4% phosphate), vacuum packaged, and aged for 7 or 14 d. Enhancement increased positive sensory attributes (tenderness, juiciness, beef flavor, saltiness) and decreased negative attributes (off-flavors) of all muscles but had greater effects on some than on others. It increased the oily mouthfeel (10%) and saltiness (40%) and decreased the L * value and chroma of the complexus (chuck). It increased tenderness, juiciness, and beef flavor and decreased off-flavors, visual red and brown colors, shear value, and cook loss of the serratus ventrali (chuck) , vastus lateralis (round), vastus medialis (round), and longissiumus dorsi (loin). Aging slightly decreased rancid and liver off-flavor scores, visual brown color, and shear value and increased the hue angle and L * and b * values.     

Anaerobic oxidation of methane: mechanisms, bioenergetics, and the ecology of associated microorganisms

Microbially mediated anaerobic oxidation of methane (AOM) moderates the input of methane, an important greenhouse gas, to the atmosphere by consuming methane produced in various marine, terrestrial, and subsurface environments. AOM coupled to sulfate reduction has been most extensively studied because of the abundance of sulfate in marine systems, but electron acceptors otherthan sulfate are more energetically favorable. Phylogenetic trees based on 16S rRNA gene clone libraries derived from microbial communities where AOM occurs show evidence of diverse, methanotrophic archaea (ANME) closely associated with sulfate-reducing bacteria, but these organisms have not yet been isolated as pure cultures. Several biochemical pathways for AOM have been proposed, including reverse methanogenesis, acetogenesis, and methylogenesis, and both culture-dependent and independent techniques have provided some clues to howthese communities function. Still, questions remain regarding the diversity, physiology, and metabolic restrictions of AOM-related organisms.     

Effect of dietary vitamin E supplementation on textural and aroma attributes of enhanced beef clod roasts in a cook/hot-hold situation

The objective of this study was to evaluate the effects of supplementing vitamin E into the diets of finishing cattle on quality characteristics of beef pumped with a phosphate/salt solution (enhanced) the cooked and held in a simulated foodservice situation. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-α-tocopheryl-acetate (E+). Paired clod roasts were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% phosphate in the finished product. Following injection, clods were allowed to equilibrate then frozen. A flavor profile panel evaluated texture attributes and aroma characteristics of roasts immediately after cooking and after 1 and 2 h of hot-holding. Pumping improved taste and textural attributes of the hot-held clod roasts. Dietary vitamin E supplementation reduced thiobarbituric acid reactive substances (TBARS) from ～0.61 to ～0.42, but over the 2-h time period, did not significantly improve aroma quality of beef roasts.     

Excitation control design of local machines in a large-scale power system by using dynamic equivalencing technique

A linear optimal control design for machine excitation is developed to improve the local system stability in a large-scale power system. Dynamic equivalents for the external system are used to provide the controller with information about the original external system. The paper investigates whether external system information helps the controller to stabilize the local system and whether the dynamic equivalents are a reliable source of that information. The validity and accuracy of the proposed method is demonstrated by simulated tests on two sample power systems.     

The case for technology in developing regions

Alongside good governance, technology is considered among the greatest enablers for improved quality of life. However, the majority of its benefits have been concentrated in industrialized nations and therefore limited to a fraction of the world's population. We believe that technology has a large role to play in developing regions, that "First World" technology to date has been a poor fit in these areas, and that there is thus a need for technology research for developing regions. Despite the relative infancy of technology studies in developing regions, anecdotal evidence suggests that access to technology has a beneficial economic impact. Cellular telephony is probably the most visible application, but there are many others, some of which we cover in this article. The World Bank's infoDev site catalogs hundreds of information and communications technologies (ICT) projects, albeit not all successful. Most of these projects use existing off-the-shelf technology designed for the industrialized world. Although it is clear that there are large differences in assumptions related to cost, power, and usage, there has been little work on how technology needs in developing regions differ from those of industrialized nations. We argue that Western market forces continue to meet the needs of developing regions accidentally at best.     

Using interval arithmetic for robust state feedback design

A problem of a modal P-regulator synthesis for a linear multivariable dynamical system with uncertain (interval) parameters in state space is considered. The designed regulator has to place all coefficients of the system characteristic polynomial within assigned intervals. We have developed the approach proposed earlier in Dugarova and Smagina (Avtomat. i Telemech. 11 (1990) 176) and proved a direct correlation between interval system controllability and existence of robust modal P-regulator.