Structural and biochemical characterization of the exopolysaccharide deacetylase Agd3 required for Aspergillus fumigatus biofilm formation

The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Deletion of a gene encoding a putative deacetylase, Agd3, leads to defects in GAG deacetylation, biofilm formation, and virulence. Here, we show that Agd3 deacetylates GAG in a metal-dependent manner, and is the founding member of carbohydrate esterase family CE18. The active site is formed by four catalytic motifs that are essential for activity. The structure of Agd3 includes an elongated substrate-binding cleft formed by a carbohydrate binding module (CBM) that is the founding member of CBM family 87. Agd3 homologues are encoded in previously unidentified putative bacterial exopolysaccharide biosynthetic operons and in other fungal genomes. The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Here, the authors study an A. fumigatus enzyme that deacetylates GAG in a metal-dependent manner and constitutes a founding member of a new carbohydrate esterase family.Bio-organic Synthesi

Absence of system xc⁻ on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis

Background: Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System x(c)- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration. Methods: Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system x(c)-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT(-/-)) mice and irradiated mice reconstituted in xCT(-/-) bone marrow (BM), to their proper wild type (xCT(+/+)) controls. Results: xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT(+/+) mice, xCT(-/-) mice were equally susceptible to EAE, whereas mice transplanted with xCT(-/-) BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected. Conclusions: Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system x(c)- on immune cells invading the CNS participates to EAE. Since a total loss of system x(c)- had no net beneficial effects, these results have important implications for targeting system x(c)- for treatment of MS

Ethnobotany of the Samburu of Mt. Nyiru, South Turkana, Kenya

Traditional plant use is of extremely high importance in many societies, and prevalent in African communities. This knowledge is however dwindling rapidly due to changes towards a more Western lifestyle. The influence of modern tourism cannot be neglected in this context. This paper examines the plant use of the Samburu of the Mt. Nyiru area in Northern Kenya. The Samburu pastoralists of Kenya are still amongst the most traditional communities of the country and have retained most of their knowledge about the use of a large part of the plants in their environment for a wide variety of purposes. The results indicate that the local population has a very high knowledge of the plants in their surroundings, and attributes a purpose to a large percentage of the plants found. 448 plant species were collected, identified and their Samburu names and traditional uses recorded. 199 species were reported as of "no use". The high proportion of 249 plant species however had some traditional use: The highest number (180 species) was used as fodder, followed by 80 species that had medicinal use. Firewood (59 species), construction (42 species), tools (31 species), food (29 species) and ceremonial use (19 species) ranked far behind. Traditionally the Samburu attribute most illnesses to the effect of pollutants that block or inhibit digestion. This can include "polluted" food, contagion through sick people as well as witchcraft. In most cases the treatment of illness involves herbal purgatives to cleanse the patient. There are however frequent indications of plant use for common problems like wounds, parasites, body aches and burns. The change from a nomadic to a more sedentary lifestyle, often observed in other areas of the country, has affected the Samburu of remote Mt. Nyiru to a much lesser extent and did so far not lead to a major loss of traditional plant knowledge. However, overgrazing and over-exploitation of plant resources have already led to a decline of the plant material available

Evidence of superficial knowledge regarding antibiotics and their use: Results of two cross-sectional surveys in an urban informal settlement in Kenya

<div><p>We assessed knowledge and practices related to antibiotic use in Kibera, an urban informal settlement in Kenya. Surveys was employed at the beginning (entry) and again at the end (exit) of a 5-month longitudinal study of AMR. Two-hundred households were interviewed at entry, of which 149 were also interviewed at exit. The majority (>65%) of respondents in both surveys could name at least one antibiotic, with amoxicillin and cotrimoxazole jointly accounting for 85% and 77% of antibiotics mentioned during entry and exit, respectively. More than 80% of respondents felt antibiotics should not be shared or discontinued following the alleviation of symptoms. Nevertheless, 66% and 74% of respondents considered antibiotics effective for treating colds and flu in the entry and exit surveys, respectively. There was a high (87%, entry; 70% exit) level of reported antibiotic use (past 12 months) mainly for colds/flu, coughs and fever, with >80% of respondents obtaining antibiotics from health facilities and pharmacies. Less than half of respondents remembered getting information on the correct use of antibiotics, although 100% of those who did reported improved attitudes towards antibiotic use. Clinicians and community pharmacists were highly trusted information sources. Paired household responses (n = 149) generally showed improved knowledge and attitudes by the exit survey although practices were largely unchanged. Weak agreement (κ = -0.003 to 0.22) between survey responses suggest both that unintended learning had not occurred, and that participant responses were not based on established knowledge or behaviors. Targeted public education regarding antibiotics is needed to address this gap.</p></div

Turning Males On: Activation of Male Courtship Behavior in Drosophila melanogaster

The innate sexual behaviors of Drosophila melanogaster males are an attractive system for elucidating how complex behavior patterns are generated. The potential for male sexual behavior in D. melanogaster is specified by the fruitless (fru) and doublesex (dsx) sex regulatory genes. We used the temperature-sensitive activator dTRPA1 to probe the roles of fruM- and dsx-expressing neurons in male courtship behaviors. Almost all steps of courtship, from courtship song to ejaculation, can be induced at very high levels through activation of either all fruM or all dsx neurons in solitary males. Detailed characterizations reveal different roles for fruM and dsx in male courtship. Surprisingly, the system for mate discrimination still works well when all dsx neurons are activated, but is impaired when all fruM neurons are activated. Most strikingly, we provide evidence for a fruM-independent courtship pathway that is primarily vision dependent

The Surveillance for Enteric Fever in Asia Project (SEAP), Severe Typhoid Fever Surveillance in Africa (SETA), Surveillance of Enteric Fever in India (SEFI), and Strategic Typhoid Alliance Across Africa and Asia (STRATAA) population-based enteric fever studies: a review of methodological similarities and differences.

Building on previous multicountry surveillance studies of typhoid and others salmonelloses such as the Diseases of the Most Impoverished program and the Typhoid Surveillance in Africa Project, several ongoing blood culture surveillance studies are generating important data about incidence, severity, transmission, and clinical features of invasive Salmonella infections in sub-Saharan Africa and South Asia. These studies are also characterizing drug resistance patterns in their respective study sites. Each study answers a different set of research questions and employs slightly different methodologies, and the geographies under surveillance differ in size, population density, physician practices, access to healthcare facilities, and access to microbiologically safe water and improved sanitation. These differences in part reflect the heterogeneity of the epidemiology of invasive salmonellosis globally, and thus enable generation of data that are useful to policymakers in decision-making for the introduction of typhoid conjugate vaccines (TCVs). Moreover, each study is evaluating the large-scale deployment of TCVs, and may ultimately be used to assess post-introduction vaccine impact. The data generated by these studies will also be used to refine global disease burden estimates. It is important to ensure that lessons learned from these studies not only inform vaccination policy, but also are incorporated into sustainable, low-cost, integrated vaccine-preventable disease surveillance systems

The Central Clock Neurons Regulate Lipid Storage in Drosophila

A proper balance of lipid breakdown and synthesis is essential for achieving energy homeostasis as alterations in either of these processes can lead to pathological states such as obesity. The regulation of lipid metabolism is quite complex with multiple signals integrated to control overall triglyceride levels in metabolic tissues. Based upon studies demonstrating effects of the circadian clock on metabolism, we sought to determine if the central clock cells in the Drosophila brain contribute to lipid levels in the fat body, the main nutrient storage organ of the fly. Here, we show that altering the function of the Drosophila central clock neurons leads to an increase in fat body triglycerides. We also show that although triglyceride levels are not affected by age, they are increased by expression of the amyloid-beta protein in central clock neurons. The effect on lipid storage seems to be independent of circadian clock output as changes in triglycerides are not always observed in genetic manipulations that result in altered locomotor rhythms. These data demonstrate that the activity of the central clock neurons is necessary for proper lipid storage

Integrating organizational, social, and individual perspectives in Web 2.0-based workplace e-learning

From the issue entitled 'Special Issue: Emerging Social and Legal Aspect'E-learning is emerging as a popular approach of education in the workplace by virtue of its flexibility to access, just-in-time delivery, and cost-effectiveness. To improve social interaction and knowledge sharing in e-learning, Web 2.0 is increasingly utilized and integrated with e-learning applications. However, existing social learning systems fail to align learning with organizational goals and individual needs in a systemic way. The dominance of technology-oriented approaches makes elearning applications less goal-effective and poor in quality and design. To solve the problem, we address the requirement of integrating organizational, social, and individual perspectives in the development of Web 2.0 elearning systems. To fulfill the requirement, a key performance indicator (KPI)-oriented approach is presented in this study. By integrating a KPI model with Web 2.0 technologies, our approach is able to: 1) set up organizational goals and link the goals with expertise required for individuals; 2) build a knowledge network by linking learning resources to a set of competences to be developed and a group of people who learn and contribute to the knowledge network through knowledge creation, sharing, and peer evaluation; and 3) improve social networking and knowledge sharing by identifying each individual's work context, expertise, learning need, performance, and contribution. The mechanism of the approach is explored and elaborated with conceptual frameworks and implementation technologies. A prototype system for Web 2.0 e-learning has been developed to demonstrate the effectiveness of the approach. © Springer Science + Business Media, LLC 2009.postprin

Phosphodiesterase-5 Inhibition Mimics Intermittent Reoxygenation and Improves Cardioprotection in the Hypoxic Myocardium

Although chronic hypoxia is a claimed myocardial risk factor reducing tolerance to ischemia/reperfusion (I/R), intermittent reoxygenation has beneficial effects and enhances heart tolerance to I/R. Aim of the study: To test the hypothesis that, by mimicking intermittent reoxygenation, selective inhibition of phosphodiesterase-5 activity improves ischemia tolerance during hypoxia. Adult male Sprague-Dawley rats were exposed to hypoxia for 15 days (10% O2) and treated with placebo, sildenafil (1.4 mg/kg/day, i. p.), intermittent reoxygenation (1 h/day exposure to room air) or both. Controls were normoxic hearts. To assess tolerance to I/R all hearts were subjected to 30-min regional ischemia by left anterior descending coronary artery ligation followed by 3 h-reperfusion. Whereas hypoxia depressed tolerance to I/R, both sildenafil and intermittent reoxygenation reduced the infarct size without exhibiting cumulative effects. The changes in myocardial cGMP, apoptosis (DNA fragmentation), caspase-3 activity (alternative marker for cardiomyocyte apoptosis), eNOS phosphorylation and Akt activity paralleled the changes in cardioprotection. However, the level of plasma nitrates and nitrites was higher in the sildenafil+intermittent reoxygenation than sildenafil and intermittent reoxygenation groups, whereas total eNOS and Akt proteins were unchanged throughout. Conclusions: Sildenafil administration has the potential to mimic the cardioprotective effects led by intermittent reoxygenation, thereby opening the possibility to treat patients unable to be reoxygenated through a pharmacological modulation of NO-dependent mechanisms

An Autotetraploid Linkage Map of Rose (Rosa hybrida) Validated Using the Strawberry (Fragaria vesca) Genome Sequence

Polyploidy is a pivotal process in plant evolution as it increase gene redundancy and morphological intricacy but due to the complexity of polysomic inheritance we have only few genetic maps of autopolyploid organisms. A robust mapping framework is particularly important in polyploid crop species, rose included (2n = 4x = 28), where the objective is to study multiallelic interactions that control traits of value for plant breeding. From a cross between the garden, peach red and fragrant cultivar Fragrant Cloud (FC) and a cut-rose yellow cultivar Golden Gate (GG), we generated an autotetraploid GGFC mapping population consisting of 132 individuals. For the map we used 128 sequence-based markers, 141 AFLP, 86 SSR and three morphological markers. Seven linkage groups were resolved for FC (Total 632 cM) and GG (616 cM) which were validated by markers that segregated in both parents as well as the diploid integrated consensus map