Habitually professional phagocytes, including macrophages, eradicate microbial invaders from the human body without overt signs of infection. Despite this, there exist select bacteria that are ...professional pathogens, causing significant morbidity and mortality across the globe and Staphylococcus aureus is no exception. S. aureus is a highly successful pathogen that can infect virtually every tissue that comprises the human body causing a broad spectrum of diseases. The profound pathogenic capacity of S. aureus can be attributed, in part, to its ability to elaborate a profusion of bacterial effectors that circumvent host immunity. Macrophages are important professional phagocytes that contribute to both the innate and adaptive immune response, however from in vitro and in vivo studies, it is evident that they fail to eradicate S. aureus. This review provides an overview of the antimicrobial mechanisms employed by macrophages to combat bacteria and describes the immune evasion strategies and some representative effectors that enable S. aureus to evade macrophage-mediated killing.
An understanding of fanners' perceptions of pests and their existing pest control methods can make an important contribution to the development of effective integrated pest management strategies. ...While the relatively successful rice IPM technologies in Asia have been extensively documented in studies examining farmers' pest perceptions and management practices, studies examining, specifically, perceptions and management practices of West African rice farmers are rare. This may reflect the more limited success to date in the implementation of rice IPM strategies in the region. This paper describes rice pests, pest perceptions and management practices of smallholder rice farmers in the Ivory Coast. It was found that the major rice pests, as perceived by farmers, are weeds, vertebrates (birds and rodents) and insects. Farmers are generally unable to diagnose rice plant diseases and thus did not consider them as important production constraints. Implications are derived for an integrated pest management strategy that incorporates farmers' perceptions and builds on their existing cultural control practices.
The African rice gall midge, Orseolia oryzivora Harris and Gagne (Diptera: Cecidomyiidae), is an important pest of rice, Oryza sativa, in Burkina Faso as well as other countries in West and East ...Africa. In spite of its importance, little is known regarding the relationship between gall midge populations and grain yield losses. To determine yield losses the gall midge was reared in cages and adult midges were placed on caged plants of the rice variety ITA 123 at different population levels. The seven treatments consisted of different numbers of insects infested on the plants; 0 insect pairs (non-infested check), and 1, 5, 10, 15, 20 or 25 midge pairs/cage. The loss in yield in relation to the non-infested control was highly positively correlated (R
2
= 0.81) with the percentage of gall midge damaged tillers. The infestation by the insect on the plants resulted in the compensatory production of tillers which developed in response to the gall midge damage but the compensation was not sufficient to make up for the loss of yield due to the damaged tillers. Yield loss ranged from 0% in the control to 65.3% in the treatment with 25 pairs of adults. One per cent of tillers damaged resulted in 2% grain yield loss.
Iron is an essential nutrient for the survival and virulence of Pseudomonas aeruginosa. The pathogen expresses at least 15 different iron‐uptake pathways, the majority involving small iron chelators ...called siderophores. P. aeruginosa produces two siderophores, but can also use many produced by other microorganisms. This implies that the bacterium expresses appropriate TonB‐dependent transporters (TBDTs) at the outer membrane to import the ferric form of each of the siderophores used. Here, we show that the two α‐carboxylate‐type siderophores rhizoferrin‐Fe and staphyloferrin A‐Fe are transported into P. aeruginosa cells by the TBDT ActA. Among the mixed α‐carboxylate/hydroxamate‐type siderophores, we found aerobactin‐Fe to be transported by ChtA and schizokinen‐Fe and arthrobactin‐Fe by ChtA and another unidentified TBDT. Our findings enhance the understanding of the adaptability of P. aeruginosa and hold significant implications for developing novel strategies to combat antibiotic resistance.
Iron is a key nutrient for the growth of almost all bacteria. The pathogen Pseudomonas aeruginosa is able to express at least 15 different iron acquisition pathways, each involving a specific outer membrane transporter. Most of these iron‐uptake pathways rely on small iron chelators (siderophores) produced by other microorganisms. We identified the outer membrane transporters involved in the uptake of iron via two α‐carboxylate siderophores and three mixed α‐carboxylate/hydroxamate siderophores.
Three tests were conducted over a 2-year period in lowland irrigated rice fields on the WARDA Research Station at Bouake, Cote d'Ivoire, to obtain information on the strepsipteran parasitism of white ...leafhoppers, Cofana spectra and C. unimaculata. Rice cultivars were sampled with a sweep net to collect leafhoppers for determination of the relative abundance of the two leafhopper species and the effect of rice cultivar and rice crop age on the leafhopper populations and percent strepsipteran parasitism. Dissections of the leafhoppers were made to determine the relative number of the various parasitic stages in the leafhoppers. Cofana unimaculata populations were higher than those of C. spectra while C. spectra parasitism by Halictophagus australensis Perkins (Strepsiptera: Halictophagidae) was higher than that of C. unimaculata. In two tests, there was a relationship between length of rice cultivar duration and C. unimaculata populations with populations being highest on the short duration cultivars. On most cultivars there was no correlation between Cofana populations and percentage parasitism, nor was there a relationship between cultivar growth duration and percent parasitism. The number of the various stages of the parasite was similar in both Cofana species with the male pupal parasitic stage being most common.
This article represents the proceedings of a symposium at the RSA meeting in Montreal, Canada. The organizer was Andrey E. Ryabinin, and the chair was George F. Koob. The presentations were (1) ...Introduction, by Stephen C. Heinrichs; (2) Role of CRF and its receptors in the hypothalamic-pituitary-adrenal response to alcohol, by Soon Lee and Catherine Rivier; (3) A role for CRF in the allostasis of alcohol dependence, by George F. Koob and Amanda J. Roberts; (4) CRF and alcohol: Lessons from knockouts, microinjections, and microdialysis, by M. Foster Olive, Kristin K. Mehmert, R. Camarini, Joseph A. Kim, Heather N. Koenig, Michelle A. Nannini, and Clyde W. Hodge; and (5) Selective sensitivity of urocortin-containing neurons to alcohol self-administration, by Andrey E. Ryabinin and Ryan K. Bachtell.
This article seeks to clarify how autonomous vehicles (AV) could affect urban planning and the built environment, to what extent these effects are compatible with municipalities’ existing objectives, ...and what lessons can be drawn from that. The paper combines a systematic review of the literature, a quantitative online survey, and qualitative interviews with representatives from urban transport planning authorities in Germany. Four concrete ‘use-cases’ were applied to structure the survey.
Results show that respondents are rather skeptical about the compatibility of AV with existing transport and urban planning objectives, above all to strengthen non-motorized transportation and to promote public transportation. Particularly, automating private motorized travel appears not to match municipal planning perspectives. On the contrary, transport planners think that shared autonomous vehicles as a complement to public transport systems are more appropriate to support urban development strategies. Their most prominent concern with respect to AV is the expectation that car travel will increase with AV, propagating problems like congestion and negative environmental effects. However, survey respondents expect that effects differ quite strongly depending on how AV will occur.
As a lesson, the study suggests that different AV use-cases should receive specific attention to explore their potentials and challenges. The study likewise suggests to, given the discrepancy between the objectives of urban transport planning and federal government‘s policy focus, consider consolidating the communal strategic positions on research and development priorities. The results indicate a demand for studies that demonstrate how AV can respond to more fundamental challenges and goals that city planner’s face. Given the wide range of potential implications, the study suggests to broaden the debate from its present primary focus on the transport planning domain to city planning and development.
Staphylococcus aureus is a significant cause of human infection. Here, we demonstrate that mutations in the transcriptional repressor of purine biosynthesis, purR, enhance the pathogenic potential of ...S. aureus. Indeed, systemic infection with purR mutants causes accelerated mortality in mice, which is due to aberrant up-regulation of fibronectin binding proteins (FnBPs). Remarkably, purR mutations can arise upon exposure of S. aureus to stress, such as an intact immune system. In humans, naturally occurring anti-FnBP antibodies exist that, while not protective against recurrent S. aureus infection, ostensibly protect against hypervirulent S. aureus infections. Vaccination studies support this notion, where anti-Fnb antibodies in mice protect against purR hypervirulence. These findings provide a novel link between purine metabolism and virulence in S. aureus.
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