Role of \u3cem\u3eCryptococcus neoformans\u3c/em\u3e Pyruvate Decarboxylase and Aldehyde Dehydrogenase Enzymes in Acetate Production and Virulence

The basidiomycete Cryptococcus neoformans is is an invasive opportunistic pathogen of the central nervous system and the most frequent cause of fungal meningitis. C. neoformans enters the host by inhalation and protects itself from immune assault in the lungs by producing hydrolytic enzymes, immunosuppressants, and other virulence factors. C. neoformans also adapts to the environment inside the host, including producing metabolites that may confer survival advantages. One of these, acetate, can be kept in reserve as a carbon source or can be used to weaken the immune response by lowering local pH or as a key part of immunomodulatory molecules. Thus, cryptococcosis could be treated by targeting acetate production. The Smith laboratory has identified two potential pathways for acetate production. The xylulose-5-phosphate/fructose-6-phosphate phosphoketolase (Xfp) - acetate kinase (Ack) pathway, previously thought to be present only in bacteria, converts phosphoketose sugars to acetate through acetyl-phosphate. The pyruvate decarboxylase (Pdc) and acetaldehyde dehydrogenase (Ald) pathway, found in other fungi, converts pyruvate to acetate through acetaldehyde. The genes encoding enzymes from these pathways have been shown to be upregulated during infection, suggesting that acetate production may be a necessary and required part of cryptococcal infection. In Saccharomyces cerevisiae, Pdc works with one or more aldehyde dehydrogenases to produce acetate. Eight of the nine C. neoformans aldehyde dehydrogenases and the sole Pdc all contributed to the cellular acetate pool, and loss of some of these enzymes reduced cell survival during growth on various carbon sources, under oxidative or nitrosative stress, under pseudo-hypoxia conditions, and when the cell wall integrity was disrupted. In addition, deletion mutants of of some of these enzymes affected capsule formation and melanization, two primary determinants of Cryptococcus, and led to decreased virulence in macrophages and Galleria mellonella, an invertebrate model of infection. Metabolic adaptability is an important attribute for fungal pathogens to successfully infect and cause disease. Carbon metabolism is critical for virulence in C. neoformans, but little is known about which carbon sources are utilized during infection. Lung alveolar macrophages, the a first line of host defense against C. neoformans infection, provide a glucose- and amino acid-poor environment, and nonpreferred carbon sources such as lactate and acetate are likely important early in establishment of a pulmonary infection. A global screening was undertaken to identify C. neoformans proteins necessary in acetate utilization, as possible drug targets. From two libraries, together comprising 3936 gene knockouts, 41 mutants failed to grow on media with either glucose or acetate as the carbon source, or on both media. Of the known proteins lacking in these mutants, most function in gluconeogenesis, arginine biosynthesis, or mitochondrial transmembrane transport. Overall, this work elucidated the roles of C. neoformans acetate production and utilization pathways in virulence

Improvement Of Molecular Methods For Detection Of Pathogenic Escherichia Coli.

Diarrhea is one of the leading causes of illnesses and death among children in developing countries, where an estimated 1.3 billion episodes and 4 to 10 million deaths occur each year in children below 5 years of age. The common pathogens of diarrhea are diarrheagenic Escherichia coli (DEC), Group A rotavirus, Shigella spp, Salmonella spp, Campylobacter, and Vibrio cholerae. Microbiological insights including phenotypic and genotypic characterisation are valuable approaches with application in management and prevention of diarrheal outbreaks by E. coli. In the present study, the Random Amplified polymorphic DNA (RAPD) fingerprinting technique allowed genetic diversity assessment of 25 E. coli isolates. Six out of 20 arbitrary primers namely, OPAE 4, 9, 10, 11, 12 and 18 produced DNA fingerprinting patterns providing the discriminatory power and the display of the potential epidemiological and diagnostic markers. A highly significant finding from the DNA fingerprinting is the display of a predominant band at a size of 308 bp when arbitrar

Digital Preservation: Handling Large Collections Case Study: Digitizing Egyptian Press Archive at Centre for Economic, Judicial, and Social Study and Documentation(CEDEJ)

Managing the digitization of large collections is quite a challenge not only in terms of quantity, but also in terms of text and material quality, designing the workflow system which organizes the operations, and handling metadata. This has been the focus of the Bibliotheca Alexandrina during its partnership with the Centre for Economic, Judicial, and Social Study and Documentation (CEDEJ), to digitize more than 800,000 pages of press articles dating back to 1976. This triggered a need to design a workflow to manage such a massive collection proficiently. This required simultaneous intervention of four main aspects; data analysis, developing a digitization workflow , implementing and installing the necessary software tools for metadata entry, and publishing the digital archive. This paper demonstrates the workflow system implemented to manage this massive press collection, yielding more than 400,000 items to date. It illustrates the BA’s Digital Assets Factory (DAF); the nucleus of the digitization process ,and the tools and stages implemented for ingesting data into the system. The outflow is also discussed in terms of organizing and grouping multipart press clips, in addition to reviewing and validating the output. The paper also discusses the challenges of associating the accessible online archive with a powerful search engine supporting multidimensional search

Adaptive Two-stage Stochastic Programming with an Application to Capacity Expansion Planning

Multi-stage stochastic programming is a well-established framework for sequential decision making under uncertainty by seeking policies that are fully adapted to the uncertainty. Often such flexible policies are not desirable, and the decision maker may need to commit to a set of actions for a number of planning periods. Two-stage stochastic programming might be better suited to such settings, where the decisions for all periods are made here-and-now and do not adapt to the uncertainty realized. In this paper, we propose a novel alternative approach, where the stages are not predetermined but part of the optimization problem. Each component of the decision policy has an associated revision point, a period prior to which the decision is predetermined and after which it is revised to adjust to the uncertainty realized thus far. We motivate this setting using the multi-period newsvendor problem by deriving an optimal adaptive policy. We label the proposed approach as adaptive two-stage stochastic programming and provide a generic mixed-integer programming formulation for finite stochastic processes. We show that adaptive two-stage stochastic programming is NP-hard in general. Next, we derive bounds on the value of adaptive two-stage programming in comparison to the two-stage and multi-stage approaches for a specific problem structure inspired by the capacity expansion planning problem. Since directly solving the mixed-integer linear program associated with the adaptive two-stage approach might be very costly for large instances, we propose several heuristic solution algorithms based on the bound analysis. We provide approximation guarantees for these heuristics. Finally, we present an extensive computational study on an electricity generation capacity expansion planning problem and demonstrate the computational and practical impacts of the proposed approach from various perspectives

Solid lipid nanoparticles preparation and characterization.

The presents study aimed to prepare and characterize Solid Lipid Nanoparticles (SLNs) from palm oil materials. Hydrogenated palm oil and lecithin incorporated with surfactant were mixed and formed by High Pressure Homogenization (HPH) at elevated temperature. Appropriate analytical methods are needed for the characterization of SLN. The use of several analytical techniques is a necessity such as particle size which determined using Photon Correlation Spectroscopy (PCS). The change of particle charge was studied by Zeta Potential (ZP) measurements, while the melting and recrystallization behavior characterized by Differential Scanning Calorimetry (DSC). Data showed physical stability of the formulation. In conclusion, the SLN presented here are well suited for several applications including drug delivery

Методика выбора параметров ПИ-регулятора для интервальной системы автоматического управления

Разработана процедура выбора настроек линейного регулятора, обеспечивающих максимальную степень устойчивости системы с интервальными параметрами. В основу процедуры положены оценка корневых робастных показателей качества (колебательности и степень устойчивости) с применением коэффициентного подхода

Effect of Arginine and nano-hydroxyapatite application on the hypersensitivity and color change of bleached enamel : a randomized controlled clinical trial

To evaluate the effect of 2.5% Arginine and nano-hydroxyapatite (nHA) application on the post-bleaching hypersensitivity (HS) and color change in a randomized controlled trial. Sixty-four participants were randomly allocated to four groups (n=16) accor

Extraction of essential oil from Nigella sativa using supercritical carbon dioxide : study of antibacterial activity.

The antimicrobial activity of N. sativa essential oil obtained by supercritical fluid extraction by carbon dioxide was investigated against Gram Positive and Gram negative strains, isolated from clinical specimens. Best conditions for Black cumin oil extraction are obtained at 400 bar, 40°C and a solvent flow rate of 25 g min-1. The seed extracts were prepared by supercritical fluid extraction method. Filter paper discs impregnated with varying concentrations of N. sativa extract were tested by the disk diffusion method. Methicillin Resistant Staphylococcus Aureus (MRSA) ATCC strain (700968), E. coli ATCC strain (25922), E. coli 0157 ATCC strain (12799), Extended-Spectrum Beta-Lactamase (ESBL) Klebsiella pneumoniae ATCC strain (700603), Carbapenam Resistant acenitobacter Baumanii (CRAB) clinical strain and Vibrio cholerae 01 Ogawa and 0139 Bengal clinical strains were investigated. The inhibition zones of the Mueller Hinton agar in different extract concentrate ion showed that at 25 mg 20 μL-1, 50 mg 20 μL-1 and 100 mg 20 μL-1, the inhibition zones increased accordingly in S. aureu. However, N. sativa was found to be inactive against ESBL producers (E. coli and K. pneumoniae)

Molecular characterization of horseshoe crab anti-lipopolysaccharide factor C-peptide for hybridization-based detection method of gram negative bacteria.

Recent advances in molecular techniques have revolutionized the detection of microorganism. The development of a molecular-based technique for detection of the three different targets of Enterbacteriacae was undertaken. Primer and probe were designed based on specific pepted of novel hemolymph protein of horseshoe crabs (Factor C anti-LPS) Tachypleus tridentatus that is believed to be involved in the binds to the lipopolysaccharide of Escherichia coli, Salmonella and Vibrio cholerae. The aim of our study the exploit part of cell wall polysaccharide in the development of improved detection method based on molecular approaches. In the gene detection assay, Lipopolysaccharide gene of Salmonella, V. cholera and E. coil were hybridized to anti-LPS factor gene found in the biolysate of the marine animals. The wzm and wzt genes encoding O-polysaccharide genes were amplified in these pathogens and the LPS factor C were amplified from the marine lysate. Development of a PCR-based technique for detection of the food-borne pathogens particularly Sa Salmonella, V. cholera and E. coil were achieved. Thus rapid, sensitive and reliable techniques for the detection of food-borne pathogens developed