Evidence of an Intracellular Reservoir in the Nasal Mucosa of Patients with Recurrent Staphylococcus aureus Rhinosinusitis

Severe infections due to Staphylococcus aureus require prolonged therapy for cure, and relapse may occur even years after the first episode. Persistence of S. aureus may be explained, in part, by nasal carriage of S. aureus which occurs in a large percentage of healthy humans and represents a major source of systemic infection. However, the persistence of internalized S. aureus within mucosal cells has not been evaluated in humans. Here, we provide the first in vivo evidence of intracellular reservoirs of S. aureus in humans, which were assessed in endonasal mucosa specimens from patients suffering from recurrent S. aureus rhinosinusitis due to unique, patient-specific bacterial clonotypes. Heavily infected foci of intracellular bacteria located in nasal epithelium, glandular, and myofibroblastic cells were revealed by inverted confocal laser scan fluorescence and electron microscopic examination of posttherapy intranasal biopsy specimens from symptom-free patients undergoing surgery on the sinuses. Intracellular residence may provide a sanctuary for pathogenic bacteria by protecting them from host defense mechanisms and antibiotic treatment during acute, recurrent S. aureus rhinosinusiti

New stable QTLs for berry weight do not colocalize with QTLs for seed traits in cultivated grapevine (Vitis vinifera L.)

International audienceBACKGROUND: In grapevine, as in other fruit crops, fruit size and seed content are key components of yield and quality; however, very few Quantitative Trait Loci (QTLs) for berry weight and seed content (number, weight, and dry matter percentage) have been discovered so far. To identify new stable QTLs for marker-assisted selection and candidate gene identification, we performed simultaneous QTL detection in four mapping populations (seeded or seedless) with various genetic backgrounds. RESULTS: For berry weight, we identified five new QTLs, on linkage groups (LGs) 1, 8, 11, 17 and 18, in addition to the known major QTL on LG 18. The QTL with the largest effect explained up to 31% of total variance and was found in two genetically distant populations on LG 17, where it colocalized with a published putative domestication locus. For seed traits, besides the major QTLs on LG 18 previously reported, we found four new QTLs explaining up to 51% of total variance, on LGs 4, 5, 12 and 14. The previously published QTL for seed number on LG 2 was found related in fact to sex. We found colocalizations between seed and berry weight QTLs only for the major QTL on LG 18 in a seedless background, and on LGs 1 and 13 in a seeded background. Candidate genes belonging to the cell number regulator CNR or cytochrome P450 families were found under the berry weight QTLs on LGs 1, 8, and 17. The involvement of these gene families in fruit weight was first described in tomato using a QTL-cloning approach. Several other interesting candidate genes related to cell wall modifications, water import, auxin and ethylene signalling, transcription control, or organ identity were also found under berry weight QTLs. CONCLUSION: We discovered a total of nine new QTLs for berry weight or seed traits in grapevine, thereby increasing more than twofold the number of reliable QTLs for these traits available for marker assisted selection or candidate gene studies. The lack of colocalization between berry and seed QTLs suggests that these traits may be partly dissociated

Polymorphisms in Plasmodium falciparum chloroquine resistance transporter and multidrug resistance 1 genes: parasite risk factors that affect treatment outcomes for P. falciparum malaria after artemether-lumefantrine and artesunate-amodiaquine.

Adequate clinical and parasitologic cure by artemisinin combination therapies relies on the artemisinin component and the partner drug. Polymorphisms in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multidrug resistance 1 (pfmdr1) genes are associated with decreased sensitivity to amodiaquine and lumefantrine, but effects of these polymorphisms on therapeutic responses to artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) have not been clearly defined. Individual patient data from 31 clinical trials were harmonized and pooled by using standardized methods from the WorldWide Antimalarial Resistance Network. Data for more than 7,000 patients were analyzed to assess relationships between parasite polymorphisms in pfcrt and pfmdr1 and clinically relevant outcomes after treatment with AL or ASAQ. Presence of the pfmdr1 gene N86 (adjusted hazards ratio = 4.74, 95% confidence interval = 2.29 - 9.78, P < 0.001) and increased pfmdr1 copy number (adjusted hazards ratio = 6.52, 95% confidence interval = 2.36-17.97, P < 0.001 : were significant independent risk factors for recrudescence in patients treated with AL. AL and ASAQ exerted opposing selective effects on single-nucleotide polymorphisms in pfcrt and pfmdr1. Monitoring selection and responding to emerging signs of drug resistance are critical tools for preserving efficacy of artemisinin combination therapies; determination of the prevalence of at least pfcrt K76T and pfmdr1 N86Y should now be routine

Contribution of teg49 Small RNA in the 5′ Upstream Transcriptional Region of sarA to Virulence in Staphylococcus aureus

High-throughput RNA sequencing technology has found the 5\u27 untranslated region of sarA to contain two putative small RNAs (sRNAs), designated teg49 and teg48. Northern blot analysis disclosed that teg49 and teg48 were detectable within the P3-P1 and P1 sarA promoter regions, respectively. Focusing on teg49, we found that this sRNA, consisting of 196 nucleotides, is transcribed in the same direction as the sarA P3 transcript. The expression of both P3 and teg49 transcripts is dependent on sigB and cshA, which encodes a DEAD box RNA helicase. Within the sRNA teg49, there are two putative hairpin-loop structures, HP1 and HP2. Transversion mutation of the HP1 loop produced a smaller amount of sarA P3 and P2 transcripts and SarA protein than the corresponding HP1 stem and the HP2 stem and loop mutations, leading to lower RNAII transcription and derepression of aur transcription. The HP1 loop mutant also exhibited less biofilm formation than the parental and complemented strains. Complementation with shuttle plasmid pEPSA5 carrying teg49 was able to reestablish sarA P3 and P2 transcription and augment RNAII expression in the HP1 loop mutant. We thus conclude that teg49, embedded within the extended promoter regions of sarA, is modulated by sigB and cshA and plays an important trans-acting role in modulating the transcription and ensuing expression of sarA

Contribution of teg49 Small RNA in the 5′ Upstream Transcriptional Region of sarA to Virulence in Staphylococcus aureus

High-throughput RNA sequencing technology has found the 5\u27 untranslated region of sarA to contain two putative small RNAs (sRNAs), designated teg49 and teg48. Northern blot analysis disclosed that teg49 and teg48 were detectable within the P3-P1 and P1 sarA promoter regions, respectively. Focusing on teg49, we found that this sRNA, consisting of 196 nucleotides, is transcribed in the same direction as the sarA P3 transcript. The expression of both P3 and teg49 transcripts is dependent on sigB and cshA, which encodes a DEAD box RNA helicase. Within the sRNA teg49, there are two putative hairpin-loop structures, HP1 and HP2. Transversion mutation of the HP1 loop produced a smaller amount of sarA P3 and P2 transcripts and SarA protein than the corresponding HP1 stem and the HP2 stem and loop mutations, leading to lower RNAII transcription and derepression of aur transcription. The HP1 loop mutant also exhibited less biofilm formation than the parental and complemented strains. Complementation with shuttle plasmid pEPSA5 carrying teg49 was able to reestablish sarA P3 and P2 transcription and augment RNAII expression in the HP1 loop mutant. We thus conclude that teg49, embedded within the extended promoter regions of sarA, is modulated by sigB and cshA and plays an important trans-acting role in modulating the transcription and ensuing expression of sarA

Characterization of RNA Helicase CshA and Its Role in Protecting mRNAs and Small RNAs of Staphylococcus aureus Strain Newman

The toxin MazFsa in Staphylococcus aureus is a sequence-specific endoribonuclease that cleaves the majority of the mRNAs in vivo but spares many essential mRNAs (e.g., secY mRNA) and, surprisingly, an mRNA encoding a regulatory protein (i.e., sarA mRNA). We hypothesize that some mRNAs may be protected by RNA-binding protein(s) from degradation by MazFsa. Using heparin-Sepharose-enriched fractions that hybridized to sarA mRNA on Northwestern blots, we identified among multiple proteins the DEAD box RNA helicase CshA (NWMN_1985 or SA1885) by mass spectroscopy. Purified CshA exhibits typical RNA helicase activities, as exemplified by RNA-dependent ATPase activity and unwinding of the DNA-RNA duplex. A severe growth defect was observed in the cshA mutant compared with the parent when grown at 25°C but not at 37°C. Activation of MazFsa in the cshA mutant resulted in lower CFU per milliliter accompanied by a precipitous drop in viability (∼40%) compared to those of the parent and complemented strains. NanoString analysis reveals diminished expression of a small number of mRNAs and 22 small RNAs (sRNAs) in the cshA mutant versus the parent upon MazFsa induction, thus implying protection of these RNAs by CshA. In the case of the sRNA teg049 within the sarA locus, we showed that the protective effect was likely due to transcript stability as revealed by reduced half-life in the cshA mutant versus the parent. Accordingly, CshA likely stabilizes selective mRNAs and sRNAs in vivo and as a result enhances S. aureus survival upon MazFsa induction during stress

The Role of Trust In The Exchange Relationship: The Case of The Kribi Fish Market

Fresh fish trade in Kribi, Cameroon is characterized by high uncertainty in a context of specific assets. Facing this uncertainty, actors have developed hybrid coordination mechanisms centered on contractual arrangements and networks. These implicit contractual arrangements involve price negotiation, delivery agreements between fishermen and buyers, as well as transactions including the provision of various types of credit. Supply networks help build trust among trading partners. Trust is based not only on strong ties through ethnic network but also on the trading partner‟s credibility brought about through repeated and lasting relationships. In theory our case study concurs with some of the Williamson‟s intuitions. The study further shows that the establishment of an "organized" market with a view to building transparency in the transactions has prompted the majority of actors to adopt this institution. At the same time, it has also loosened some of the social relationships otherwise indispensible in the absence of a viable marketing institution. Institutional trust does not, however, completely replace relational trust between actors given the low development of microcredit in the area.Keywords: Markets and Trade, Fisheries Economics, Markets and LabelsKeywords: Markets and Trade, Fisheries Economics, Markets and Label