Cell-free culture medium of <Emphasis Type=Italic>Burkholderia cepacia</Emphasis> improves seed germination and seedling growth in maize (<Emphasis Type=Italic>Zea mays</Emphasis>) and rice (<Emphasis Type=Italic>Oryza sativa</Emphasis>)

The saprophytic bacterium Burkholderia cepacia has been shown to play an active role as plant growth promoting bacteria (PGPB). In this study, the ability of cell-free culture medium (CFCM) of B. cepacia to improve early developmental stages of plants has been assessed on two agronomically important crops, maize (Zea mays) and rice (Oryza sativa). Treating maize and rice seeds for 45 min before germination significantly improved seed germination and consequent seedling growth. The effect of CFCM was confirmed by the increased biomass of the shoot and, mainly, the root systems of treated seedlings. Chromatographic characterization of the CFCM revealed that the spent culture medium of B. cepacia is a complex mix of different classes of metabolites including, among others, salicylic acid, indole-3-acetic acid (IAA) and several unidentified phenolic compounds. Fractionation of the CFCM components revealed that the impressive development of the root system of CFCM-treated seedlings is due to the synergistic action of several groups of components rather than IAA alone. The data presented here suggest that a CFCM of B. cepacia can be used to improve crop germination.     

Laboratory and Field Evaluation of the Partec CyFlow MiniPOC for Absolute and Relative CD4 T-Cell Enumeration

BackgroundA new CD4 point-of-care instrument, the CyFlow miniPOC, which provides absolute and percentage CD4 T-cells, used for screening and monitoring of HIV-infected patients in resource-limited settings, was introduced recently. We assessed the performance of this novel instrument in a reference laboratory and in a field setting in Senegal.MethodologyA total of 321 blood samples were obtained from 297 adults and 24 children, all HIV-patients attending university hospitals in Dakar, or health centers in Ziguinchor. Samples were analyzed in parallel on CyFlow miniPOC, FACSCount CD4 and FACSCalibur to assess CyFlow miniPOC precision and accuracy.ResultsAt the reference lab, CyFlow miniPOC, compared to FACSCalibur, showed an absolute mean bias of -12.6 cells/mm³ and a corresponding relative mean bias of -2.3% for absolute CD4 counts. For CD4 percentages, the absolute mean bias was -0.1%. Compared to FACSCount CD4, the absolute and relative mean biases were -31.2 cells/mm³ and -4.7%, respectively, for CD4 counts, whereas the absolute mean bias for CD4 percentages was 1.3%. The CyFlow miniPOC was able to classify HIV-patients eligible for ART with a sensitivity of ≥ 95% at the different ART-initiation thresholds (200, 350 and 500 CD4 cells/mm3). In the field lab, the room temperature ranged from 30 to 35°C during the working hours. At those temperatures, the CyFlow miniPOC, compared to FACSCount CD4, had an absolute and relative mean bias of 7.6 cells/mm³ and 2.8%, respectively, for absolute CD4 counts, and an absolute mean bias of 0.4% for CD4 percentages. The CyFlow miniPOC showed sensitivity equal or greater than 94%.ConclusionThe CyFlow miniPOC showed high agreement with FACSCalibur and FACSCount CD4. The CyFlow miniPOC provides both reliable absolute CD4 counts and CD4 percentages even under the field conditions, and is suitable for monitoring HIV-infected patients in resource-limited settings.     

Discovery of a potent series of non-steroidal non α-trifluoromethyl carbinol glucocorticoid receptor agonists with reduced lipophilicity

A novel series of indazole non-steroidal glucocorticoid receptor agonist has been discovered. This series features a sulfonamide central core and meta amides which interact with the extended ligand binding domain. This series has produced some of the most potent and least lipophilic agonists of which we are aware such as 20a (NFκB pIC₅₀ 8.3 (100%), c log P 1.9). Certain analogues in this series also display evidence for modulated pharmacology.     

Seasonal climate effects anemotaxis in newly emerged adult Anopheles gambiae Giles in Mali, West Africa

The direction and magnitude of movement by the malaria vector Anopheles gambiae Giles has been of great interest to medical entomologists for over 70 years. This direction of movement is likely to be affected by many factors, from environmental conditions and stage of life history of the mosquito to the existence of attractants in the vicinity. We report here the direction of movement of newly emerged An. gambiae in nature, around the village of Donéguébougou, Mali. We assessed the direction of movement for individual mosquitoes by placing them in a novel enclosure with exit traps oriented in the direction of the cardinal and intermediate points of the compass. We consistently found predominantly Southward directions of movement during 2009 and 2010, with an additional Eastward component during the dry season and a Westward one during the wet season. Our data indicate that wind has an important effect on the direction of movement, but that this effect varied by season: Average directions of movement were downwind during the dry season and upwind during the wet season. A switch in anemotactic response suggests that the direction of movement of An. gambiae relative to the wind immediately after emergence under varying conditions of humidity should be further investigated under controlled conditions.     

Temporal distribution and spatial pattern of abundance of the Rift Valley fever and West Nile fever vectors in Barkedji, Senegal

The temporal distribution and spatial pattern of abundance of mosquito vectors of Rift Valley fever (RVf) and West Nile fever (WNf) were studied during the 2005 and 2006 rainy seasons at Barkedji, Senegal. Mosquitoes were collected every two weeks with CDC light traps with dry ice at 79 sites including temporary ponds, barren, shrubby savannah, wooded savannah, steppes, and villages at different distances (between 0 and 600 m) from the nearest pond. The temporal distributions of these vectors varied between 2005 and 2006 and were positively correlated with rainfall for Aedes (Aedimorphus) vexans Patton, with rainfall after a lag time of one month for Culex (Culex) poicilipes (Theobald) and Culex (Culex) neavei Theobald. All the vectors had their highest abundances and parity rates between September and November. The highest vector abundances were observed in the barren and temporary ponds. The distance of trap location to the nearest ponds was negatively correlated to the abundance of the vectors. Taking into account the linear regression equations, it was predicted that mosquitoes would not disperse and be collected by the light trap, up to 1,500 m to the nearest ponds. The implications of these findings in the epidemiology and control of RVF and WNF at Barkedji are discussed.     

Pre-Hospital Risk Factors for Inpatient Death from Severe Febrile Illness in Malian Children

Background

Inpatient case fatality from severe malaria remains high in much of sub-Saharan Africa. The majority of these deaths occur within 24 hours of admission, suggesting that pre-hospital management may have an impact on the risk of case fatality.

Methods

Prospective cohort study, including questionnaire about pre-hospital treatment, of all 437 patients admitted with severe febrile illness (presumed to be severe malaria) to the paediatric ward in Sikasso Regional Hospital, Mali, in a two-month period.

Findings

The case fatality rate was 17.4%. Coma, hypoglycaemia and respiratory distress at admission were associated with significantly higher mortality. In multiple logistic regression models and in a survival analysis to examine pre-admission risk factors for case fatality, the only consistent and significant risk factor was sex. Girls were twice as likely to die as boys (AOR 2.00, 95% CI 1.08–3.70). There was a wide variety of pre-hospital treatments used, both modern and traditional. None had a consistent impact on the risk of death across different analyses. Reported use of traditional treatments was not associated with post-admission outcome.

Interpretation

Aside from well-recognised markers of severity, the main risk factor for death in this study was female sex, but this study cannot determine the reason why. Differences in pre-hospital treatments were not associated with case fatality.     

Control of Dioscorea alata microtuber dormancy and germination by jasmonic acid

Effects of appling exogenous jasmonic acid (JA) on the germination of Dioscorea alata L. microtubers were examined on Murashige and Skoog (MS) medium. Microtuber germination was promoted by JA (0.1 and 1 M) supplemented to the culture medium but higher concentrations (30 and 100 M) completely inhibited germination. When these inhibited microtubers were transferred to hormone-free medium, germination resumed.After transfer to greenhouse conditions, almost all plants (95%) from tubers previously cultivated on MS medium with 100 M JA survived and all acclimatized plants had produced tubers after 8 months. It is concluded that depending on JA concentration, both the germination and dormancy processes in D. alata microtubers were affected. The release from dormancy is easily obtained by transferring dormant microtubers to hormone-free medium.     

Multi-locus genotyping reveals established endemicity of a geographically distinct Plasmodium vivax population in Mauritania,West Africa

BackgroundPlasmodium vivax has been recently discovered as a significant cause of malaria in Mauritania, although very rare elsewhere in West Africa. It has not been known if this is a recently introduced or locally remnant parasite population, nor whether the genetic structure reflects epidemic or endemic transmission.Methodology/Principal findingsTo investigate the P. vivax population genetic structure in Mauritania and compare with populations previously analysed elsewhere, multi-locus genotyping was undertaken on 100 clinical isolates, using a genome-wide panel of 38 single nucleotide polymorphisms (SNPs), plus seven SNPs in drug resistance genes. The Mauritanian P. vivax population is shown to be genetically diverse and divergent from populations elsewhere, indicated consistently by genetic distance matrix analysis, principal components analyses, and fixation indices. Only one isolate had a genotype clearly indicating recent importation, from a southeast Asian source. There was no linkage disequilibrium in the local parasite population, and only a small number of infections appeared to be closely genetically related, indicating that there is ongoing genetic recombination consistent with endemic transmission. The P. vivax diversity in a remote mining town was similar to that in the capital Nouakchott, with no indication of local substructure or of epidemic population structure. Drug resistance alleles were virtually absent in Mauritania, in contrast with P. vivax in other areas of the world.Conclusions/SignificanceThe molecular epidemiology indicates that there is long-standing endemic transmission that will be very challenging to eliminate. The virtual absence of drug resistance alleles suggests that most infections have been untreated, and that this endemic infection has been more neglected in comparison to P. vivax elsewhere.     

Dynamics of lysozyme and its hydration water under an electric field

The effects of a static electric field on the dynamics of lysozyme and its hydration water are investigated by means of incoherent quasi-elastic neutron scattering (QENS). Measurements were performed on lysozyme samples, hydrated respectively with heavy water (D ₂O) to capture the protein dynamics and with light water (H ₂O), to probe the dynamics of the hydration shell, in the temperature range from 210 < T < 260 K. The hydration fraction in both cases was about ～ 0.38 gram of water per gram of dry protein. The field strengths investigated were respectively 0 kV/mm and 2 kV/mm ( ～2 × 10 ⁶ V/m) for the protein hydrated with D ₂O and 0 kV and 1 kV/mm for the H ₂O-hydrated counterpart. While the overall internal protons dynamics of the protein appears to be unaffected by the application of an electric field up to 2 kV/mm, likely due to the stronger intra-molecular interactions, there is also no appreciable quantitative enhancement of the diffusive dynamics of the hydration water, as would be anticipated based on our recent observations in water confined in silica pores under field values of 2.5 kV/mm. This may be due to the difference in surface interactions between water and the two adsorption hosts (silica and protein), or to the existence of a critical threshold field value E _c ～2–3 kV/mm for increased molecular diffusion, for which electrical breakdown is a limitation for our sample.