Differential Modulation of Quorum Sensing Signaling through QslA in Pseudomonas aeruginosa Strains PAO1 and PA14

Two clinical isolates of the opportunist pathogen Pseudomonas aeruginosa named PAO1 and PA14 are commonly studied in research laboratories. Despite the isolates being closely related, PA14 exhibits increased virulence compared to that of PAO1 in various models. To determine which players are responsible for the hypervirulence phenotype of the PA14 strain, we elected a transcriptomic approach through RNA sequencing. We found 2,029 genes that are differentially expressed between the two strains, including several genes that are involved with or regulated by quorum sensing (QS), known to control most of the virulence factors in P. aeruginosa Among them, we chose to focus our study on QslA, an antiactivator of QS whose expression was barely detectable in the PA14 strain according our data. We hypothesized that lack of expression of qslA in PA14 could be responsible for higher QS expression in the PA14 strain, possibly explaining its hypervirulence phenotype. After confirming that QslA protein was highly produced in PAO1 but not in the PA14 strain, we obtained evidence showing that a PAO1 deletion strain of qslA has faster QS gene expression kinetics than PA14. Moreover, known virulence factors activated by QS, such as (i) pyocyanin production, (ii) H2-T6SS (type VI secretion system) gene expression, and (iii) Xcp-T2SS (type II secretion system) machinery production and secretion, were all lower in PAO1 than in PA14, due to higher qslA expression. However, biofilm formation and cytotoxicity toward macrophages, although increased in PA14 compared to PAO1, were independent of QslA control. Together, our findings implicated differential qslA expression as a major determinant of virulence factor expression in P. aeruginosa strains PAO1 and PA14.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen responsible for acute nosocomial infections and chronic pulmonary infections. P. aeruginosa strain PA14 is known to be hypervirulent in different hosts. Despite several studies in the field, the underlining molecular mechanisms sustaining this phenotype remain enigmatic. Here we provide evidence that the PA14 strain has faster quorum sensing (QS) kinetics than the PAO1 strain, due to the lack of QslA expression, an antiactivator of QS. QS is a major regulator of virulence factors in P. aeruginosa; therefore, we propose that the hypervirulent phenotype of the PA14 strain is, at least partially, due to the lack of QslA expression. This mechanism could be of great importance, as it could be conserved among other P. aeruginosa isolates.

Epstein-Barr virus-associated smooth muscle tumors in a composite tissue allograft and a pediatric liver transplant recipient

Epstein-Barr virus (EBV) is known to establish latent infections in B-lymphocytes that can cause lymphoproliferative disorders particularly in immunocompromised patients. More recently, the development of rare EBV-associated smooth muscle tumors has been reported in transplant recipients. We herein describe 2 new cases of EBV-associated post-transplant smooth muscle tumors (EBV-PTSMT), including the first in a facial composite tissue graft recipient. Among the striking features shared by these 2 patients were their young ages, the fact that they were naïve for EBV before the transplantation, that they developed a post-transplant lymphoproliferative disorder before the diagnosis of EBV-PTSMT, and that they responded favorably to reduction of immunosuppression. Radiological and histologic features of EBV-PTSMT are shown. Finally, pathophysiology and therapeutic management of EBV-PTSMT are discussed based on a comprehensive review of the literature.

The first simultaneous kidney-adrenal gland-pancreas transplantation: outcome at 1 year

Adrenal insufficiency is a rare but life-threatening disease. Replacement therapy sometimes fails to prevent an acute adrenal crisis and most often does not lead to restoration of well-being. We report here the 1-year outcome of the first simultaneous kidney-adrenal gland-pancreas transplantation in a 33-year-old patient with type 1 diabetes and concomitant autoimmune adrenal insufficiency. En bloc left adrenal gland and kidney grafts were anastomosed on the left iliac vessels in normal vascular conditions and the pancreas graft was anastomosed on the right iliac vessels. The immunosuppressive regimen was not modified by the addition of the adrenal gland. We observed no additional morbidity due to the adrenal gland transplantation, as there were no surgical complications. One-year kidney and pancreas graft functions were satisfactory (estimated glomerular filtration rate: 55 mL/min/1.73 m(2) and HbA1c: 4.8%). The adrenal graft functioned well at 12 months with a normalization of cortisol and aldosterone baseline levels. Functional imaging at 3 months showed good uptake of [(123) I]-metaiodobenzylguanidine by the adrenal graft. Transplantation of the adrenal gland en bloc with the left kidney appears to be a good therapeutic option in patients with adrenal insufficiency awaiting kidney or kidney-pancreas transplantation.

Kidney graft outcome and quality (after transplantation) from uncontrolled deceased donors after cardiac arrest

The use of uncontrolled deceased donors after cardiac arrest (uDDCA) has been developed in France to compensate for organ shortage. The quality of these kidneys remains unclear. We analyzed kidney graft function and histology from 27 uDDCA and compared them with kidneys from 30 extended criteria donors (ECD) and from 24 simultaneous pancreas kidney (SPK) donors as a control group of optimal deceased donors. Kidneys from ECD and SPK donors were preserved by static cold storage while kidneys from uDDCA were preserved by pulsatile perfusion. The uDDCA graft function at 3 years posttransplantation (estimated with MDRD and measured with inulin clearance) did not differ from that of the ECD group (eGFR 44.1 vs. 37.4 mL/min/1.73 m(2) , p = 0.13; mGFR 44.6 vs. 36.1 mL/min/1.73 m(2) , p = 0.07 in the uDDCA and ECD groups, respectively). The histological assessment of 3-month and 1-year protocol biopsies did not show differences for interstitial lesions between the uDDCA and ECD grafts (IF score at M3 was 30 vs. 28% and at M12 36 vs. 33%, p = NS). In conclusion, the results at 3 years with carefully selected and machine-perfused uDDCA kidneys have been comparable to ECD kidneys and encourage continuation of this program and development of similar programs.

Cutaneous bacillary angiomatosis in renal transplant recipients: report of three new cases and literature review

Bacillary angiomatosis (BA) is a rare vasculoproliferative disorder due to Bartonella henselae (BH) or Bartonella quintana. It can involve many organs, including the skin, and has been mainly reported in patients with acquired immunodeficiency syndrome. In organ transplant recipients (OTR), this disorder remains misdiagnosed and therapeutic guidelines are nonexistent. We report 3 cases of BA with skin involvement in OTR and review similar cases from the literature. BA manifests on the skin with violaceous lesions mimicking Kaposi sarcoma, and is associated with fever, lymphadenopathy, and liver, spleen, or lung nodules. Bartonellosis infections in OTR are due to BH, the agent causing cat-scratch disease (CSD), but BA comprises histologically a prominent vascular proliferation, which is usually lacking in CSD. Cultures and serologic tests are poorly reliable for the diagnosis, which relies on demonstration of BH within the lesions. A history of cat exposure exists in most cases and pediatric OTR are at higher risk. Prevention consists of regular use of a flea-control product in cats and prompt cleaning of scratches. Our cases highlight several original features of this rare condition, which could potentially improve the management of BA in OTR.

Carbon contamination of soft X-ray beamlines: dramatic anti-reflection coating effects observed in the 1 keV photon energy region

Carbon contamination is a general problem of under-vacuum optics submitted to high fluence. In soft X-ray beamlines carbon deposit on optics is known to absorb and scatter radiation close to the C K-edge (280 eV), forbidding effective measurements in this spectral region. Here the observation of strong reflectivity losses is reported related to carbon deposition at much higher energies around 1000 eV, where carbon absorptivity is small. It is shown that the observed effect can be modelled as a destructive interference from a homogeneous carbon thin film.

Brain regions associated with the reversal of cocaine conditioned place preference by environmental enrichment

In addition to the known preventive effects of environmental enrichment (EE) on drug addiction, we have recently shown that EE can also have "curative" effects and eliminate addiction-related behaviors in mice and rats. In the present study, using Fos immunohistochemistry, we investigated brain regions involved in the elimination of cocaine conditioned place preference (CPP) produced by a 30-day exposure to EE. A first group of mice was conditioned to cocaine in the CPP apparatus, a second group that served as control received cocaine in a cage different from the CPP apparatus and a third control group received only saline injections. At the end of conditioning, we kept mice abstinent in the animal facility, housing them in standard environments (SE) or EE for 30 days and then we tested them for expression of CPP. SE, but not EE mice, conditioned to cocaine showed long-lasting preferences for the cocaine-paired compartment. Expression of CPP was paralleled by significant increases in the expression of Fos in the anterior cingulate cortex, the lateral caudate putamen, the shell of the nucleus accumbens, the dentate gyrus of the hippocampus, the basolateral and central nuclei of amygdala, the bed nucleus of the stria terminalis, and the ventral tegmental area. In contrast, EE mice showed levels of expression of FOS similar to control groups. These results demonstrate that EE can eliminate context-induced cocaine seeking and that this effect appears associated with a general reduction in the activation of several brain regions implicated in relapse.

Time-resolved photoelectron spectroscopy using synchrotron radiation time structure

Synchrotron radiation time structure is becoming a common tool for studying dynamic properties of materials. The main limitation is often the wide time domain the user would like to access with pump-probe experiments. In order to perform photoelectron spectroscopy experiments over time scales from milliseconds to picoseconds it is mandatory to measure the time at which each measured photoelectron was created. For this reason the usual CCD camera-based two-dimensional detection of electron energy analyzers has been replaced by a new delay-line detector adapted to the time structure of the SOLEIL synchrotron radiation source. The new two-dimensional delay-line detector has a time resolution of 5 ns and was installed on a Scienta SES 2002 electron energy analyzer. The first application has been to characterize the time of flight of the photoemitted electrons as a function of their kinetic energy and the selected pass energy. By repeating the experiment as a function of the available pass energy and of the kinetic energy, a complete characterization of the analyzer behaviour in the time domain has been obtained. Even for kinetic energies as low as 10 eV at 2 eV pass energy, the time spread of the detected electrons is lower than 140 ns. These results and the time structure of the SOLEIL filling modes assure the possibility of performing pump-probe photoelectron spectroscopy experiments with the time resolution given by the SOLEIL pulse width, the best performance of the beamline and of the experimental station.

Fumagillin for treatment of intestinal microsporidiosis in renal transplant recipients

We report 10 cases of intestinal microsporidiosis due to Enterocytozoon bieneusi in renal transplant (RT) recipients who were treated with fumagillin. All patients presented with afebrile subacute diarrhea (median of 2 weeks), associated with abdominal cramps (n = 5), and weight loss (n = 6), a mean of 68 months after RT. The diagnosis was made by the identification of microsporidial spores in stools with the use of appropriate staining and confirmed by a specific polymerase chain reaction assay for E. bieneusi in 7 patients. Median CD4 cell count was 292 cells/mm(3). All patients received a median of 14 days of oral fumagillin (20 mg tid), and four patients also discontinued or tapered their immunosuppressive regimen (mycophenolate mofetil in 3, and azathioprine in 2). Clinical symptoms resolved rapidly with the clearance of microsporidial spores from stools in all patients. A severe but reversible thrombocytopenia was observed in one patient during fumagillin therapy, and another patient presented with abdominal cramps. Trough levels of tacrolimus measured in seven patients dropped below 5 ng/mL in six of them after 7-14 days of fumagillin. Intestinal microsporidiosis can cause subacute diarrhea in RT recipients. Fumagillin is an effective treatment with an acceptable safety profile, but monitoring of tacrolimus levels is warranted.

Parasites of recruiting coral reef fish larvae in New Caledonia

Recruiting coral reef fish larvae from 38 species and 19 families from New Caledonia were examined for parasites. We found 13 parasite species (Platyhelminthes: Monogenea, Cestoda and Trematoda) but no acanthocephalan, crustacean or nematode parasites. Over 23% of individual fish were infected. Didymozoid metacercariae were the most abundant parasites. We conclude that most of the parasites are pelagic species that become 'lost' once the fish larvae have recruited to the reef. Larval coral reef fish probably contribute little to the dispersal of the parasites of the adult fish so that parasite dispersal is more difficult than that of the fish themselves.

Modulation of the far-upstream enhancer of the rat alpha-fetoprotein gene by members of the ROR alpha, Rev-erb alpha, and Rev-erb beta groups of monomeric orphan nuclear receptors

Expression of the oncodevelopmental alpha-fetoprotein (AFP) gene is tightly regulated and occurs in the yolk sac, fetal liver and intestine, and cancerous liver cells. Transcription of the AFP gene is under the control of three enhancers that are very tissue specific. We have shown that the most upstream of these enhancers, located at -6 kb, works through the combined action of liver-enriched factors and nuclear receptors that bind to three regions of this DNA regulatory element. This study showed that orphan nuclear receptors of the ROR alpha, Re-verb alpha, and Rev-erb beta groups can bind as monomers with high affinity and specificity to an evolutionarily conserved AGGTCA motif in the functionally important region 1 of this AFP enhancer. Transient transfection experiments performed with human HepG2 hepatoma cells showed that overproduction of ROR alpha 4 stimulated the activity of the AFP enhancer in a dose-dependent manner, while that of Rev-erb alpha and Rev-erb beta had the opposite effect. These effects were highly specific and required the integrity of the AGGTCA motif. The action of these nuclear receptors also occurred in the context of the entire 7-kb regulatory region of the rat AFP gene. These results suggest that altering the amounts or activities of these orphan receptors in cells of hepatic or endodermal origin could modulate AFP gene expression in response to a variety of developmental or carcinogenic stimuli.

[Spawn and spat collecting relationship in Mimachlamys gloriosa (Reeve, 1853) and Brachtechlamys vexillum (Reeve, 1853), Pectinids of New Caledonia]

Pectinidae spat collecting was carried out during a period of 1.5 years in the southern lagoon of New Caledonia. The majority of spat collected were constituted by Mimachlamys gloriosa and Brachtechlamys vexillum larvae. Settlement showed quantitative variations during the year with a maximum in June-September and a minimum (close to zero) in summer (February). However, although adult stocks maintain a stable density and spawn all the year round, spawning intensity shows a maximum in austral summer, contrarily to the recruitment. Therefore, spawning and spat collecting present no correlation and high values of the gonadic index are not followed by numerous spat collecting. These two tropical species present an opportunistic reproductive model.

Endoparasite species richness of new caledonian butterfly fishes: host density and diet matter

Ecological factors may influence the number of parasites encountered and, thus, parasite species richness. These factors include diet, gregarity, conspecific and total host density, habitat, body size, vagility, and migration. One means of examining the influence of these factors on parasite species richness is through a comparative analysis of the parasites of different, but related, host species. In contrast to most comparative studies of parasite species richness of fish, which have been conducted by using data from the literature, the present study uses data obtained by the investigators. Coral reef fishes vary widely in the above ecological factors and are frequently parasitized by a diverse array of parasites. We, therefore, chose to investigate how the above ecological factors influence parasite species richness in coral reef fishes. We investigated the endoparasite species richness of 21 species of butterfly fishes (Chaetodontidae) of New Caledonia. We mapped the diet characters on the existing butterfly fish phylogeny and found that omnivory appears to be ancestral. We also mapped the estimated endoparasite species richness, coded from low to high parasite species richness, on the existing butterfly fish phylogeny and found that low parasite species richness appears to be associated with the ancestral state of omnivory. Different dietary and social strategies appear to have evolved more than once, with the exception of obligate coralivory, which appears to have evolved only once. Finally, after controlling for phylogenetic relationships, we found that only the percentage of plankton in the diet and conspecific host density were positively correlated with endoparasite species richness.

Intoxication from Veratrum album

Two new cases of Veratrum poisoning are described. Clinical symptoms occurred quickly, within 30 min. Vomiting, a fall in blood pressure and bradycardia were observed. The outcome was favourable in both cases, producing a cure without sequellae. Examination of the literature showed that such cases are nearly always accidental, resulting from the difficulty in distinguishing Veratrum album and Gentiana.