The potential contribution of aquatic wildlife to antibiotic resistance dissemination in freshwater ecosystems: A review

Antibiotic resistance (AR) is one of the major health threats of our time. The presence of antibiotics in the environment and their continuous release from sewage treatment plants, chemical manufacturing plants and animal husbandry, agriculture and aquaculture, result in constant selection pressure on microbial organisms. This presence leads to the emergence, mobilization, horizontal gene transfer and a selection of antibiotic resistance genes, resistant bacteria and mobile genetic elements. Under these circumstances, aquatic wildlife is impacted in all compartments, including freshwater organisms with partially impermeable microbiota. In this narrative review, recent advancements in terms of occurrence of antibiotics and antibiotic resistance genes in sewage treatment plant effluents source compared to freshwater have been examined, occurrence of antibiotic resistance in wildlife, as well as experiments on antibiotic exposure. Based on this current state of knowledge, we propose the hypothesis that freshwater aquatic wildlife may play a crucial role in the dissemination of antibiotic resistance within the environment. Specifically, we suggest that organisms with high bacterial density tissues, which are partially isolated from the external environment, such as fishes and amphibians, could potentially be reservoirs and amplifiers of antibiotic resistance in the environment, potentially favoring the increase of the abundance of antibiotic resistance genes and resistant bacteria. Potential avenues for further research (trophic transfer, innovative exposure experiment) and action (biodiversity eco-engineering) are finally proposed.

Development of an in vitro biofilm model for the study of the impact of fluoroquinolones on sewer biofilm microbiota

Sewer biofilms are likely to constitute hotspots for selecting and accumulating antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). This study aimed to optimize culture conditions to obtain in vitro biofilms, mimicking the biofilm collected in sewers, to study the impact of fluoroquinolones (FQs) on sewer biofilm microbiota. Biofilms were grown on coupons in CDC Biofilm Reactors®, continuously fed with nutrients and inoculum (1/100 diluted wastewater). Different culture conditions were tested: (i) initial inoculum: diluted wastewater with or without sewer biofilm, (ii) coupon material: concrete vs. polycarbonate, and (iii) time of culture: 7 versus 14 days. This study found that the biomass was highest when in vitro biofilms were formed on concrete coupons. The biofilm taxonomic diversity was not affected by adding sewer biofilm to the initial inoculum nor by the coupon material. Pseudomonadales, Burkholderiales and Enterobacterales dominated in the sewer biofilm composition, whereas in vitro biofilms were mainly composed of Enterobacterales. The relative abundance of qnrA, B, D and S genes was higher in in vitro biofilms than sewer biofilm. The resistome of sewer biofilm showed the highest Shannon diversity index compared to wastewater and in vitro biofilms. A PCoA analysis showed differentiation of samples according to the nature of the sample, and a Procrustes analysis showed that the ARG changes observed were linked to changes in the microbial community. The following growing conditions were selected for in vitro biofilms: concrete coupons, initial inoculation with sewer biofilm, and a culture duration of 14 days. Then, biofilms were established under high and low concentrations of FQs to validate our in vitro biofilm model. Fluoroquinolone exposure had no significant impact on the abundance of qnr genes, but high concentration exposure increased the proportion of mutations in gyrA (codons S83L and D87N) and parC (codon S80I). In conclusion, this study allowed the determination of the culture conditions to develop an in vitro model of sewer biofilm; and was successfully used to investigate the impact of FQs on sewer microbiota. In the future, this setup could be used to clarify the role of sewer biofilms in disseminating resistance to FQs in the environment.

Biogeography of microbial communities in high-latitude ecosystems: Contrasting drivers for methanogens, methanotrophs and global prokaryotes

Methane-cycling is becoming more important in high-latitude ecosystems as global warming makes permafrost organic carbon increasingly available. We explored 387 samples from three high-latitudes regions (Siberia, Alaska and Patagonia) focusing on mineral/organic soils (wetlands, peatlands, forest), lake/pond sediment and water. Physicochemical, climatic and geographic variables were integrated with 16S rDNA amplicon sequences to determine the structure of the overall microbial communities and of specific methanogenic and methanotrophic guilds. Physicochemistry (especially pH) explained the largest proportion of variation in guild composition, confirming species sorting (i.e., environmental filtering) as a key mechanism in microbial assembly. Geographic distance impacted more strongly beta diversity for (i) methanogens and methanotrophs than the overall prokaryotes and, (ii) the sediment habitat, suggesting that dispersal limitation contributed to shape the communities of methane-cycling microorganisms. Bioindicator taxa characterising different ecological niches (i.e., specific combinations of geographic, climatic and physicochemical variables) were identified, highlighting the importance of Methanoregula as generalist methanogens. Methylocystis and Methylocapsa were key methanotrophs in low pH niches while Methylobacter and Methylomonadaceae in neutral environments. This work gives insight into the present and projected distribution of methane-cycling microbes at high latitudes under climate change predictions, which is crucial for constraining their impact on greenhouse gas budgets.

Esophageal cancer - French intergroup clinical practice guidelines for diagnosis, treatments and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, RENAPE, SNFCP, AFEF, SFR)

INTRODUCTION

This document is a summary of the French intergroup guidelines regarding the management of esophageal cancer (EC) published in July 2022, available on the website of the French Society of Gastroenterology (SNFGE) (www.tncd.org).

METHODS

This collaborative work was conducted under the auspices of several French medical and surgical societies involved in the management of EC. Recommendations were graded in three categories (A, B and C), according to the level of evidence found in the literature until April 2022.

RESULTS

EC diagnosis and staging evaluation are mainly based on patient's general condition assessment, endoscopy plus biopsies, TAP CT-scan and 18F FDG-PET. Surgery alone is recommended for early-stage EC, while locally advanced disease (N+ and/or T3-4) is treated with perioperative chemotherapy (FLOT) or preoperative chemoradiation (CROSS regimen) followed by immunotherapy for adenocarcinoma. Preoperative chemoradiation (CROSS regimen) followed by immunotherapy or definitive chemoradiation with the possibility of organ preservation are the two options for squamous cell carcinoma. Salvage surgery is recommended for incomplete response or recurrence after definitive chemoradiation and should be performed in an expert center. Treatment for metastatic disease is based on systemic therapy including chemotherapy, immunotherapy or combined targeted therapy according to biomarkers testing such as HER2 status, MMR status and PD-L1 expression.

CONCLUSION

These guidelines are intended to provide a personalised therapeutic strategy for daily clinical practice and are subject to ongoing optimization. Each individual case should be discussed by a multidisciplinary team.

A deep learning system for detection of early Barrett's neoplasia: a model development and validation study

BACKGROUND

Computer-aided detection (CADe) systems could assist endoscopists in detecting early neoplasia in Barrett's oesophagus, which could be difficult to detect in endoscopic images. The aim of this study was to develop, test, and benchmark a CADe system for early neoplasia in Barrett's oesophagus.

METHODS

The CADe system was first pretrained with ImageNet followed by domain-specific pretraining with GastroNet. We trained the CADe system on a dataset of 14 046 images (2506 patients) of confirmed Barrett's oesophagus neoplasia and non-dysplastic Barrett's oesophagus from 15 centres. Neoplasia was delineated by 14 Barrett's oesophagus experts for all datasets. We tested the performance of the CADe system on two independent test sets. The all-comers test set comprised 327 (73 patients) non-dysplastic Barrett's oesophagus images, 82 (46 patients) neoplastic images, 180 (66 of the same patients) non-dysplastic Barrett's oesophagus videos, and 71 (45 of the same patients) neoplastic videos. The benchmarking test set comprised 100 (50 patients) neoplastic images, 300 (125 patients) non-dysplastic images, 47 (47 of the same patients) neoplastic videos, and 141 (82 of the same patients) non-dysplastic videos, and was enriched with subtle neoplasia cases. The benchmarking test set was evaluated by 112 endoscopists from six countries (first without CADe and, after 6 weeks, with CADe) and by 28 external international Barrett's oesophagus experts. The primary outcome was the sensitivity of Barrett's neoplasia detection by general endoscopists without CADe assistance versus with CADe assistance on the benchmarking test set. We compared sensitivity using a mixed-effects logistic regression model with conditional odds ratios (ORs; likelihood profile 95% CIs).

FINDINGS

Sensitivity for neoplasia detection among endoscopists increased from 74% to 88% with CADe assistance (OR 2·04; 95% CI 1·73-2·42; p<0·0001 for images and from 67% to 79% [2·35; 1·90-2·94; p<0·0001] for video) without compromising specificity (from 89% to 90% [1·07; 0·96-1·19; p=0·20] for images and from 96% to 94% [0·94; 0·79-1·11; ] for video; p=0·46). In the all-comers test set, CADe detected neoplastic lesions in 95% (88-98) of images and 97% (90-99) of videos. In the benchmarking test set, the CADe system was superior to endoscopists in detecting neoplasia (90% vs 74% [OR 3·75; 95% CI 1·93-8·05; p=0·0002] for images and 91% vs 67% [11·68; 3·85-47·53; p<0·0001] for video) and non-inferior to Barrett's oesophagus experts (90% vs 87% [OR 1·74; 95% CI 0·83-3·65] for images and 91% vs 86% [2·94; 0·99-11·40] for video).

INTERPRETATION

CADe outperformed endoscopists in detecting Barrett's oesophagus neoplasia and, when used as an assistive tool, it improved their detection rate. CADe detected virtually all neoplasia in a test set of consecutive cases.

FUNDING

Olympus.

Gut microbiota impairment following graphene oxide exposure is associated to physiological alterations in Xenopus laevis tadpoles

Graphene-based nanomaterials such as graphene oxide (GO) possess unique properties triggering high expectations for the development of technological applications. Thus, GO is likely to be released in aquatic ecosystems. It is essential to evaluate its ecotoxicological potential to ensure a safe use of these nanomaterials. In amphibians, previous studies highlighted X. laevis tadpole growth inhibitions together with metabolic disturbances and genotoxic effects following GO exposure. As GO is known to exert bactericidal effects whereas the gut microbiota constitutes a compartment involved in host homeostasis regulation, it is important to determine if this microbial compartment constitutes a toxicological pathway involved in known GO-induced host physiological impairments. This study investigates the potential link between gut microbial communities and host physiological alterations. For this purpose, X. laevis tadpoles were exposed during 12 days to GO. Growth rate was monitored every 2 days and genotoxicity was assessed through enumeration of micronucleated erythrocytes. Genomic DNA was also extracted from the whole intestine to quantify gut bacteria and to analyze the community composition. GO exposure led to a dose dependent growth inhibition and genotoxic effects were detected following exposure to low doses. A transient decrease of the total bacteria was noticed with a persistent shift in the gut microbiota structure in exposed animals. Genotoxic effects were associated to gut microbiota remodeling characterized by an increase of the relative abundance of Bacteroides fragilis. The growth inhibitory effects would be associated to a shift in the Firmicutes/Bacteroidetes ratio while metagenome inference suggested changes in metabolic pathways and upregulation of detoxification processes. This work indicates that the gut microbiota compartment is a biological compartment of interest as it is integrative of host physiological alterations and should be considered for ecotoxicological studies as structural or functional impairments could lead to later life host fitness loss.

A combined microbial and biogeochemical dataset from high-latitude ecosystems with respect to methane cycle

High latitudes are experiencing intense ecosystem changes with climate warming. The underlying methane (CH₄) cycling dynamics remain unresolved, despite its crucial climatic feedback. Atmospheric CH₄ emissions are heterogeneous, resulting from local geochemical drivers, global climatic factors, and microbial production/consumption balance. Holistic studies are mandatory to capture CH₄ cycling complexity. Here, we report a large set of integrated microbial and biogeochemical data from 387 samples, using a concerted sampling strategy and experimental protocols. The study followed international standards to ensure inter-comparisons of data amongst three high-latitude regions: Alaska, Siberia, and Patagonia. The dataset encompasses different representative environmental features (e.g. lake, wetland, tundra, forest soil) of these high-latitude sites and their respective heterogeneity (e.g. characteristic microtopographic patterns). The data included physicochemical parameters, greenhouse gas concentrations and emissions, organic matter characterization, trace elements and nutrients, isotopes, microbial quantification and composition. This dataset addresses the need for a robust physicochemical framework to conduct and contextualize future research on the interactions between climate change, biogeochemical cycles and microbial communities at high-latitudes.

Measurement(s)	microbial diversity • microbial abundances • cations and anions • trace elements
Technology Type(s)	MiSeq sequencing 16S rRNA gene • Real Time PCR • HPLC • ICP-MS
Sample Characteristic - Organism	bacteria • archaea
Sample Characteristic - Environment	lake water • lake sediment • wetland • peatland • soil • pond
Sample Characteristic - Location	Western Siberia • Alaska • Patagonia • Cape Horn province • Magellanic subantarctic ecoregion

Combining sequential extraction and 3D fluorescence to investigate the behavior of antibiotic and polycyclic aromatic hydrocarbons during solar drying of sewage sludge

Solar drying and liming are commonly used for sludge treatment, but little is known about their efficiency on antibiotics and Polycyclic Aromatic Hydrocarbons (PAHs) removal. This study aimed to investigate the removal of antibiotics and PAHs during solar drying of Limed Sludge (LS) and Non-Limed Sludge (NLS). Thus, organic matter fractionation and 3D fluorescence were used to assess the accessibility and the complexity of organic matter. 2 experiments have been conducted using LS and NLS for 45 days of drying in a pilot scale tunnel. Physicochemical results indicated significant decrease of water content (90%) for both sludge samples within 15 days of drying. For both treatments, the removal of total organic carbon and total nitrogen was low and similar for both treatments. Through this study, it has been confirmed that liming and drying contributed to a strong modification of the organic matter quality with an increase of its accessibility. On the other hand, drying alone increased the less accessible compartments, while the presence of lime affected the interconnexion between the organic matter pools. 3D fluorescence confirmed the obtained results and indicated that LS leads to obtaining more simple molecules in the most accessible compartments, while NLS leads to obtaining more complex molecules in the less accessible compartments. In addition, solar radiations and leaching may contribute to the significant removal (p < 0.01) of roxithromycin, benzo(a)anthracene, chrysene, benzo[k]fluoranthene, benzo[a]pyrene, and benzo(g, h, i) perylene in the presence of lime. Furthermore, the evolution of organic matter pools in terms of accessibility and complexity may drive the bioavailability of these pollutants, leading to their significant removal.

Temperature differently affected methanogenic pathways and microbial communities in sub-Antarctic freshwater ecosystems

Freshwater ecosystems are responsible for an important part of the methane (CH₄) emissions which are likely to change with global warming. This study aims to evaluate temperature-induced (from 5 to 20 °C) changes on microbial community structure and methanogenic pathways in five sub-Antarctic lake sediments from Magallanes strait to Cape Horn, Chile. We combined in situ CH₄ flux measurements, CH₄ production rates (MPRs), gene abundance quantification and microbial community structure analysis (metabarcoding of the 16S rRNA gene). Under unamended conditions, a temperature increase of 5 °C doubled MPR while microbial community structure was not affected. Stimulation of methanogenesis by methanogenic precursors as acetate and H₂/CO₂, resulted in an increase of MPRs up to 127-fold and 19-fold, respectively, as well as an enrichment of mcrA-carriers strikingly stronger under acetate amendment. At low temperatures, H₂/CO₂-derived MPRs were considerably lower (down to 160-fold lower) than the acetate-derived MPRs, but the contribution of hydrogenotrophic methanogenesis increased with temperature. Temperature dependence of MPRs was significantly higher in incubations spiked with H₂/CO₂ (c. 1.9 eV) compared to incubations spiked with acetate or unamended (c. 0.8 eV). Temperature was not found to shape the total microbial community structure, that rather exhibited a site-specific variability among the studied lakes. However, the methanogenic archaeal community structure was driven by amended methanogenic precursors with a dominance of Methanobacterium in H₂/CO₂-based incubations and Methanosarcina in acetate-based incubations. We also suggested the importance of acetogenic H₂-production outcompeting hydrogenotrohic methanogenesis especially at low temperatures, further supported by homoacetogen proportion in the microcosm communities. The combination of in situ-, and laboratory-based measurements and molecular approaches indicates that the hydrogenotrophic pathway may become more important with increasing temperatures than the acetoclastic pathway. In a continuously warming environment driven by climate change, such issues are crucial and may receive more attention.

Graphene-Based Nanomaterials Modulate Internal Biofilm Interactions and Microbial Diversity

Graphene-based nanomaterials (GBMs), such as graphene oxide (GO) and reduced graphene oxide (rGO), possess unique properties triggering high expectations for the development of new technological applications and are forecasted to be produced at industrial-scale. This raises the question of potential adverse outcomes on living organisms and especially toward microorganisms constituting the basis of the trophic chain in ecosystems. However, investigations on GBMs toxicity were performed on various microorganisms using single species that are helpful to determine toxicity mechanisms but fail to predict the consequences of the observed effects at a larger organization scale. Thus, this study focuses on the ecotoxicological assessment of GO and rGO toward a biofilm composed of the diatom Nitzschia palea associated to a bacterial consortium. After 48 and 144 h of exposure to these GBMs at 0, 0.1, 1, and 10 mg.L⁻¹, their effects on the diatom physiology, the structure, and the metabolism of bacterial communities were measured through the use of flow cytometry, 16S amplicon sequencing, and Biolog ecoplates, respectively. The exposure to both of these GBMs stimulated the diatom growth. Besides, GO exerted strong bacterial growth inhibition as from 1 mg.L⁻¹, influenced the taxonomic composition of diatom-associated bacterial consortium, and increased transiently the bacterial activity related to carbon cycling, with weak toxicity toward the diatom. On the contrary, rGO was shown to exert a weaker toxicity toward the bacterial consortium, whereas it influenced more strongly the diatom physiology. When compared to the results from the literature using single species tests, our study suggests that diatoms benefited from diatom-bacteria interactions and that the biofilm was able to maintain or recover its carbon-related metabolic activities when exposed to GBMs.

Ecotoxicological assessment of commercial boron nitride nanotubes toward Xenopus laevis tadpoles and host-associated gut microbiota

Despite the growing interest for boron nitride nanotubes (BNNT) due to their unique properties, data on the evaluation of the environmental risk potential of this emerging engineered nanomaterial are currently lacking. Therefore, the ecotoxicity of a commercial form of BNNT (containing tubes, hexagonal-boron nitride, and boron) was assessed in vivo toward larvae of the amphibian Xenopus laevis. Following the exposure, multiple endpoints were measured in the tadpoles as well as in bacterial communities associated to the host gut. Exposure to BNNT led to boron accumulation in host tissues and was not associated to genotoxic effects. However, the growth of the tadpoles increased due to BNNT exposure. This parameter was associated to remodeling of gut microbiome, benefiting to taxa from the phylum Bacteroidetes. Changes in relative abundance of this phylum were positively correlated to larval growth. The obtained results support the finding that BNNT are biocompatible as indicated by the absence of toxic effect from the tested nanomaterials. In addition, byproducts, especially free boron present in the tested product, were overall beneficial for the metabolism of the tadpoles.

Anaerobic oxidation of methane and associated microbiome in anoxic water of Northwestern Siberian lakes

Arctic lakes emit methane (CH₄) to the atmosphere. The magnitude of this flux could increase with permafrost thaw but might also be mitigated by microbial CH₄ oxidation. Methane oxidation in oxic water has been extensively studied, while the contribution of anaerobic oxidation of methane (AOM) to CH₄ mitigation is not fully understood. We have investigated four Northern Siberian stratified lakes in an area of discontinuous permafrost nearby Igarka, Russia. Analyses of CH₄ concentrations in the water column demonstrated that 60 to 100% of upward diffusing CH₄ was oxidized in the anoxic layers of the four lakes. A combination of pmoA and mcrA gene qPCR and 16S rRNA gene metabarcoding showed that the same taxa, all within Methylomonadaceae and including the predominant genus Methylobacter as well as Crenothrix, could be the major methane-oxidizing bacteria (MOB) in the anoxic water of the four lakes. Correlation between Methylomonadaceae and OTUs within Methylotenera, Geothrix and Geobacter genera indicated that AOM might occur in an interaction between MOB, denitrifiers and iron-cycling partners. We conclude that MOB within Methylomonadaceae could have a crucial impact on CH₄ cycling in these Siberian Arctic lakes by mitigating the majority of produced CH₄ before it leaves the anoxic zone. This finding emphasizes the importance of AOM by Methylomonadaceae and extends our knowledge about CH₄ cycle in lakes, a crucial component of the global CH₄ cycle.

Computed tomography features of acinar cell carcinoma of the pancreas

PURPOSE

To report the computed tomography (CT) features of pancreatic acinar cell carcinoma (ACC) and identify CT features that may help discriminate between pancreatic ACC and pancreatic ductal adenocarcinoma (PDA).

MATERIALS AND METHODS

The CT examinations of 20 patients (13 men, 7 women; mean age, 66.5±10.7 [SD] years; range: 51-88 years) with 20 histopathologically proven pancreatic ACC were reviewed. CT images were analyzed qualitatively and quantitatively and compared to those obtained in 20 patients with PDA. Comparisons were performed using univariate analysis with a conditional logistic regression model.

RESULTS

Pancreatic ACC presented as an enhancing (20/20; 100%), oval (15/20; 75%), well-delineated (14/20; 70%) and purely solid (13/20; 65%) pancreatic mass with a mean diameter of 52.6±28.0 (SD) mm (range: 24-120mm) in association with visible lymph nodes (14/20; 70%). At univariate analysis, well-defined margins (Odds ratio [OR], 7.00; P=0.005), nondilated bile ducts (OR, 9.00; P=0.007), visible lymph nodes (OR, 4.33; P=0.028) and adjacent organ involvement (OR, 5.67; P=0.02) were the most discriminating CT features to differentiate pancreatic ACC from PDA. When present, lymph nodes were larger in patients with pancreatic ACC (14±4.8 [SD]; range: 7-25mm) than in those with PDA (8.8±4.1 [SD]; range: 5-15mm) (P=0.039).

CONCLUSION

On CT, pancreatic ACC presents as an enhancing, predominantly oval and purely solid pancreatic mass that most frequently present with no bile duct dilatation, no visible lymph nodes, no adjacent organ involvement and larger visible lymph nodes compared to PDA.

Sub-oxycline methane oxidation can fully uptake CH4 produced in sediments: case study of a lake in Siberia

It is commonly assumed that methane (CH₄) released by lakes into the atmosphere is mainly produced in anoxic sediment and transported by diffusion or ebullition through the water column to the surface of the lake. In contrast to that prevailing idea, it has been gradually established that the epilimnetic CH₄ does not originate exclusively from sediments but is also locally produced or laterally transported from the littoral zone. Therefore, CH₄ cycling in the epilimnion and the hypolimnion might not be as closely linked as previously thought. We utilized a high-resolution method used to determine dissolved CH₄ concentration to analyze a Siberian lake in which epilimnetic and hypolimnetic CH₄ cycles were fully segregated by a section of the water column where CH₄ was not detected. This layer, with no detected CH₄, was well below the oxycline and the photic zone and thus assumed to be anaerobic. However, on the basis of a diffusion-reaction model, molecular biology, and stable isotope analyses, we determined that this layer takes up all the CH₄ produced in the sediments and the deepest section of the hypolimnion. We concluded that there was no CH₄ exchange between the hypolimnion (dominated by methanotrophy and methanogenesis) and the epilimnion (dominated by methane lateral transport and/or oxic production), resulting in a vertically segregated lake internal CH₄ cycle.

Gut microbiota of aquatic organisms: A key endpoint for ecotoxicological studies

Gut microbial communities constitute a compartment of crucial importance in regulation of homeostasis of multiple host physiological functions as well as in resistance towards environmental pollutants. Many chemical contaminants were shown to constitute a major threat for gut bacteria. Changes in gut microbiome could lead to alteration of host health. The access to high-throughput sequencing platforms permitted a great expansion of this discipline in human health while data from ecotoxicological studies are scarce and particularly those related to aquatic pollution. The main purpose of this review is to summarize recent body of literature providing data obtained from microbial community surveys using high-throughput 16S rRNA sequencing technology applied to aquatic ecotoxicity. Effects of pesticides, PCBs, PBDEs, heavy metals, nanoparticles, PPCPs, microplastics and endocrine disruptors on gut microbial communities are presented and discussed. We pointed out difficulties and limits provided by actual methodologies. We also proposed ways to improve understanding of links between changes in gut bacterial communities and host fitness loss, along with further applications for this emerging discipline.

Differences in resource use lead to coexistence of seed-transmitted microbial populations

Seeds are involved in the vertical transmission of microorganisms in plants and act as reservoirs for the plant microbiome. They could serve as carriers of pathogens, making the study of microbial interactions on seeds important in the emergence of plant diseases. We studied the influence of biological disturbances caused by seed transmission of two phytopathogenic agents, Alternaria brassicicola Abra43 (Abra43) and Xanthomonas campestris pv. campestris 8004 (Xcc8004), on the structure and function of radish seed microbial assemblages, as well as the nutritional overlap between Xcc8004 and the seed microbiome, to find seed microbial residents capable of outcompeting this pathogen. According to taxonomic and functional inference performed on metagenomics reads, no shift in structure and function of the seed microbiome was observed following Abra43 and Xcc8004 transmission. This lack of impact derives from a limited overlap in nutritional resources between Xcc8004 and the major bacterial populations of radish seeds. However, two native seed-associated bacterial strains belonging to Stenotrophomonas rhizophila displayed a high overlap with Xcc8004 regarding the use of resources; they might therefore limit its transmission. The strategy we used may serve as a foundation for the selection of seed indigenous bacterial strains that could limit seed transmission of pathogens.

MR imaging features of pancreatic acinar cell carcinoma

PURPOSE

This study aimed to report the magnetic resonance imaging (MRI) features of acinar cell carcinoma (ACC) of the pancreas including diffusion-weighted MRI findings.

MATERIALS AND METHODS

The MRI examinations of five patients (3 men, 2 women; median age, 61years) with histopathologically proven ACC of the pancreas were retrospectively reviewed. MR images were analyzed qualitatively (location, shape, homogeneity, signal intensity, vascular involvement and extrapancreatic extent of ACC) and quantitatively (tumor size, apparent diffusion coefficient [ADC] and normalized ADC of ACC).

RESULTS

All ACC were visible on MRI, presenting as an oval pancreatic mass (5/5; 100%), with moderate and heterogeneous enhancement (5/5; 100%), with a median transverse diameter of 43mm (Q₁, 35; Q₃, 82mm; range: 30-91mm). Tumor capsule was visible in 4/5 ACC (80%) and Wirsung duct enlargement in 2/5 ACC (40%). On diffusion-weighted MRI, all ACC (5/5; 100%) were hyperintense on the 3 b value images. Median ADC value of ACC was 1.061×10^-3mm²/s (Q₁, 0.870×10^-3mm²/s; Q₃, 1.138×10^-3mm²/s; range: 0.834-1.195×10^-3mm²/s). Median normalized ADC ratio of ACC was 1.127 (Q₁, 1.071; Q₃, 1.237; range: 1.054-1.244).

CONCLUSIONS

On MRI, ACC of the pancreas presents as a large, oval pancreatic mass with moderate and heterogeneous enhancement after intravenous administration of a gadolinium chelate, with restricted diffusion and a median ADC value of 1.061×10^-3mm²/s on diffusion-weighted MRI. Further studies however are needed to confirm our findings obtained in a limited number of patients.

Transfer and Ecotoxicity of Titanium Dioxide Nanoparticles in Terrestrial and Aquatic Ecosystems: A Microcosm Study

With the advancement in nanotechnology, particularly the use of TiO₂ nanoparticles (NPs), there is a need to study their release into the environment and assess the related risk in an environmentally relevant contamination scenario. In the present study, the transfer and toxicity of TiO₂ NPs in microcosms mimicking terrestrial and aquatic ecosystems were evaluated. The contaminated soil was prepared by spiking natural soils, with these then used as the basis for all exposure systems including preparation of soil leachates for amphibian exposure. Results demonstrated significant reductions in bacterial (-45%) and archaeal (-36%) nitrifier abundance; significant translocation of Ti to M. truncatula leaves (+422%); significant reductions in plant height (-17%), number of leaves (-29%), and aboveground biomass (-53%); nonsignificant Ti uptake in snail foot and viscera, and excretion in feces; and genotoxicity to X. laevis larvae (+119% micronuclei). Our study highlights a possible risk of engineered TiO₂ NPs in the environment in terms of trophic transfer and toxicity in both terrestrial and aquatic environments.

A pressurized liquid extraction approach followed by standard addition method and UPLC-MS/MS for a fast multiclass determination of antibiotics in a complex matrix

In this work a fast analytical method for the determination of macrolides, tetracyclines and fluoroquinolones in a compost originating from a mixture of sewage sludge, palm waste and grass was developed by ultra-high performance liquid chromatography coupled to mass spectrometry (U-HPLC/MS). Antibiotics were extracted from compost by using the accelerated solvent extraction (ASE). The chromatographic separation was carried out on a T3 Cortecs C18 column using a mobile phase gradient mixture of water acidified with 1% of formic acid and acetonitrile. Recoveries of 24-30%, 53-93%, 33-57%, 69-135% and 100-171% were obtained for roxithromycin (ROX), chlortetracycline (CTC), oxytetracycline (OTC), enrofloxacin (ENR) and ciprofloxacin (CIP), respectively. As the most part of antibiotics showed significant matrix effect (ME), the method was validated using the standard addition method (SAM) to correct the observed ME. Instrumental variation, of LC/MS system, showed that 93.75% of the relative standard deviation (RSD %) are below 15%, although the organic load of extracts. This analytical method was applied to assess the fate of antibiotics during composting. Two composting experiments were conducted separately after spiking sludge at 2 different concentrations levels. The resulting elimination rates were of 52-76, 69-100, 100 and 24-50% for ROX, CTC, OTC and CIP, respectively. These results suggest that composting process contributes to the removal of residuals concentrations of macrolides and tetracyclines while the fluoroquinolones persist in the final compost product.

Human and veterinary antibiotics during composting of sludge or manure: Global perspectives on persistence, degradation, and resistance genes

Wastewater treatment plant effluent, sludge and manure are the main sources of contamination by antibiotics in the whole environment compartments (soil, sediment, surface and underground water). One of the major consequences of the antibiotics discharge into the environment could be the prevalence of a bacterial resistance to antibiotic. In this review, four groups of antibiotics (Tetracyclines, Fluoroquinolones, Macrolides and Sulfonamides) were focused for the background on their wide spread occurrence in sludge and manure and for their effects on several target and non-target species. The antibiotics concentrations range between 1 and 136,000 μg kg^-1 of dry matter in sludge and manure, representing a potential risk for the human health and the environment. Composting of sludge or manure is a well-known and used organic matter stabilization technology, which could be effective in reducing the antibiotics levels as well as the antibiotic resistance genes. During sludge or manure composting, the antibiotics removals range between 17-100%. The deduced calculated half-lives range between 1-105 days for most of the studied antibiotics. Nevertheless, these removals are often based on the measurement of concentration without considering the matter removal (lack of matter balance) and very few studies are emphasized on the removal mechanisms (biotic/abiotic, bound residues formation) and the potential presence of more or less hazardous transformation products. The results from the few studies on the fate of the antibiotic resistance genes during sludge or manure composting are still inconsistent showing either decrease or increase of their concentration in the final product. Whether for antibiotic or antibiotic resistance genes, additional researches are needed, gathering chemical, microbiological and toxicological data to better understand the implied removal mechanisms (chemical, physical and biological), the interactions between both components and the environmental matrices (organic, inorganic bearing phases) and how composting process could be optimized to reduce the discharge of antibiotics and antibiotic resistance genes into the environment.

Evaluation of the antibiotics effects on the physical and chemical parameters during the co-composting of sewage sludge with palm wastes in a bioreactor

The objective of this study was to investigate thermal and physicochemical parameters of sewage sludge-palm waste mixtures contaminated by different families of antibiotics (tetracyclines, macrolides and fluoroquinolones) during co-composting. Sludge was spiked with chlortetracycline (CTC), oxytetracycline (OTC), roxithromycin (RXY), enrofloxacin (ENR) and ciprofloxacin (CIP). Antibiotics were spiked at a low level, medium level, high level and a control without antibiotics was conducted. The results showed that the organic matter degradation was delayed and the carbon/nitrogen (C/N) ratio was affected by an increase of the antibiotics concentration. The presence of antibiotics, especially at high level, delayed the coming of the temperature maxima, and disturbed the thermophilic phase. The calorific model showed that the heat release is affected during the thermophilic phase when high antibiotics concentrations were used. In addition, the microbiological approach showed that the adsorption of antibiotics on the rachis could be probably responsible of the fungi inhibition especially during the maturation phase. Therefore, the medium and high levels of antibiotics affected the thermal, physical and chemical parameters as well as the compost quality.

Diagnosis of acute overt gastrointestinal bleeding with CT-angiography: Comparison of the diagnostic performance of individual acquisition phases

PURPOSE

To compare the respective values of arterial phase, portal venous phase and combination of phases using 64-section multidetector computed tomography (MDCT) for diagnosing acute overt gastrointestinal bleeding (AOGIB).

PATIENTS AND METHODS

Forty-nine patients with AOGIB were included. There were 30 men and 19 women, with a mean age of 65.4±15.6 (SD) years [range, 34-91years]. Two observers reviewed MDCT examinations in consensus for presence of active bleeding, location of bleeding site and nature of causative lesion. The different acquisition phases were reviewed independently.

RESULTS

AOGIB was identified in 28/49 patients (57%) with the multiphasic set, in 26/49 patients (53%) with arterial phase and in 25/49 patients (51%) with portal venous phase. Multiphasic set helped locate the bleeding site in 40/49 patients (82%). The cause was elucidated in 23/49 patients (47%) with multiphasic set. The differences between set performances were not statistically significant. Sensitivity for depicting AOGIB with the multiphasic set was 92% and specificity was 76%.

CONCLUSION

Multiphasic 64-section MDCT has high diagnostic performances in patients with AOGIB. Further studies with a larger population are needed to reach statistical significance and demonstrate better diagnostic performance of multiphasic MDCT in comparison with the arterial or portal phase alone.

Self-assembling peptide matrix for the prevention of esophageal stricture after endoscopic resection: a randomized controlled trial in a porcine model

Esophageal stricture formation after extensive endoscopic resection remains a major limitation of endoscopic therapy for early esophageal neoplasia. This study assessed a recently developed self-assembling peptide (SAP) matrix as a wound dressing after endoscopic resection for the prevention of esophageal stricture. Ten pigs were randomly assigned to the SAP or the control group after undergoing a 5-cm-long circumferential endoscopic submucosal dissection of the lower esophagus. Esophageal diameter on endoscopy and esophagogram, weight variation, and histological measurements of fibrosis, granulation tissue, and neoepithelium were assessed in each animal. The rate of esophageal stricture at day 14 was 40% in the SAP-treated group versus 100% in the control group (P = 0.2). Median interquartile range (IQR) esophageal diameter at day 14 was 8 mm (2.5-9) in the SAP-treated group versus 4 mm (3-4) in the control group (P = 0.13). The median (IQR) stricture indexes on esophagograms at day 14 were 0.32 (0.14-0.48) and 0.26 (0.14-0.33) in the SAP-treated and control groups, respectively (P = 0.42). Median (IQR) weight variation during the study was +0.2 (-7.4; +1.8) and -3.8 (-5.4; +0.6) in the SAP-treated and control groups, respectively (P = 0.9). Fibrosis, granulation tissue, and neoepithelium were not significantly different between the groups. The application of SAP matrix on esophageal wounds after a circumferential endoscopic submucosal dissection delayed the onset of esophageal stricture in a porcine model.

Topical hemostatic powder promotes reepithelialization and reduces scar formation after extensive esophageal mucosal resection

The development of techniques for endoscopic resection has provided new strategies for radical conservative treatment of superficial esophageal neoplasms, even those that are circumferential, such as Barrett's neoplasia. However, it is necessary to prevent the formation of scar tissue that can be responsible for esophageal strictures following circumferential resection. Preliminary data have suggested the possible efficacy of a hemostatic powder in the promotion of wound healing. The study aims to assess the effectiveness of Hemospray (Cook Medical) in a swine model of post-endoscopic esophageal stricture. Our prospective controlled study included 21 pigs. A 6-cm circumferential submucosal dissection of the esophagus (CESD) was performed in each pig. Group 1 (n = 11) only underwent CESD and Group 2 (n = 10) had repeated Hemospray applications after CESD. Clinical, endoscopic, and radiological monitoring were performed, blood levels of four inflammatory or pro-fibrotic cytokines were assessed, and histological analysis was performed. Median esophageal diameter was greater in the group treated with Hemospray (2 mm [1-3] vs. 3 mm [2-4], P = 0.01), and the rate of symptomatic esophageal stricture was 100% and 60% in Groups 1 and 2, respectively (P = 0.09). The thicknesses of esophageal fibrosis and inflammatory cell infiltrate were significantly lower in Group 2 than in Group 1 (P = 0.002 and 0.0003, respectively). The length of the neoepithelium was greater in Group 2 than in Group 1 (P = 0.0004). Transforming growth factor-β levels were significantly lower in Group 2 than in Group 1 (P = 0.01). The application of Hemospray after esophageal CESD reduces scar tissue formation and promotes reepithelialization, and therefore is a promising therapeutic approach in the prevention of post-endoscopic esophageal stricture.

Diagnostic yield of 24-hour esophageal manometry in non-cardiac chest pain

BACKGROUND

In the past, ambulatory 24-h manometry has been shown useful for the evaluation of patients with non-cardiac chest pain (NCCP). With the diagnostic improvements brought by pH-impedance monitoring and high-resolution manometry (HRM), the contribution of ambulatory 24-h manometry to the diagnosis of esophageal hypertensive disorders has become uncertain. Our aim was to assess the additional diagnostic yield of ambulatory manometry to HRM and ambulatory pH-impedance monitoring in this patient population.

METHODS

All patients underwent 24-h ambulatory pressure-pH-impedance monitoring and HRM. Patients had retrosternal pain as a predominant symptom and no explanation after cardiologic and digestive endoscopic evaluations. Diagnostic measurements were analyzed by two independent physicians.

KEY RESULTS

Fifty-nine patients met the inclusion criteria; 37.3% of the patients had their symptoms explained by abnormalities on pH-impedance monitoring and 6.8% by ambulatory manometry. Functional chest pain was diagnosed in 52.5% of the patients. High-resolution manometry, using the Chicago Classification v3.0 criteria alone, did not identify any of the four patients with esophageal spasm on ambulatory manometry. However, taking into account other abnormalities, such as simultaneous (rapid) or repetitive contractions, HRM had a sensitivity of 75% and a specificity of 98.2% for the diagnosis of esophageal spasm.

CONCLUSIONS & INFERENCES

In the work-up of NCCP, ambulatory 24-h manometry has a low additional diagnostic yield. However, it remains the best technique to identify esophageal spasm as the cause of symptoms. This is particularly useful when an unequivocal diagnosis is needed before treatment.

Systematic review: the prevention of oesophageal stricture after endoscopic resection

BACKGROUND

Extensive endoscopic resections for the treatment of early oesophageal neoplasia can result in fibro-inflammatory strictures that require repeated interventions, which significantly alter the patients' quality of life.

AIMS

To review current evidence about the prevention of oesophageal strictures following endoscopic resections.

METHODS

Systematic search of PubMed and Embase from inception to March 2015 using appropriate keywords. All original publications in English were included, and articles on the treatment of oesophageal stricture were excluded.

RESULTS

Of the 461 hits, 62 studies were included in the analysis. Among the wound-protective strategies, polyglycolic acid sheets showed the most convincing evidence with a 37.5% stricture rate and excellent safety. Regenerative medicine, using cell sheets of autologous keratinocytes, resulted in a 25% stricture rate, although with cost and availability concerns. Among anti-proliferative treatment modalities, steroid treatment, either endoscopically injected triamcinolone in the resection wound or orally administered prednisolone, proved effective with an overall stricture rate of 13.5%, with safety concerns regarding late oesophageal perforations and infectious morbidity. Among mechanical treatment options, poorly effective and high-risk preventive balloon dilation tend to be replaced by prophylactic covered stent, with 18-28% stricture rates.

CONCLUSIONS

Although oral or locally injected steroids are promising options, no currently available technique is sufficiently efficient and devoid of significant safety concerns to recommend its routine use for the prevention of strictures after extensive endoscopic resection. Improving our knowledge in the mechanisms of oesophageal wound healing will guide the development of novel methods for stricture prevention.

New urban wastewater treatment with autotrophic membrane bioreactor at low chemical oxygen demand/N substrate ratio

The potential for total nitrogen removal from municipal wastewater has been evaluated in an autotrophic membrane bioreactor running with a low chemical oxygen demand (COD)/N ratio to simulate its combination with an upstream physicochemical process that retains a large proportion of organic matter. The tests were conducted in a laboratory scale submerged membrane bioreactor loaded with a synthetic influent. Nitrogen loading rate was 0.16 kgN-NH4+.m(-3).d(-1) and sodium acetate was added as a carbon source. Results have shown that nitrogen elimination can reach 85% for a COD/N ratio of 5, with COD removal exceeding 97%. However, a COD/N ratio of 3.5 was found to be the limiting factor for successfully reaching the overall target value of 10 mgN.L(-1) in the effluent. Nevertheless, low COD/N ratios make it possible to work with low total suspended solid concentrations in the bioreactor, which greatly facilitates membrane fouling control by a simple aeration and backwashing strategy.

Bacterial-fungal interactions: hyphens between agricultural, clinical, environmental, and food microbiologists

Bacteria and fungi can form a range of physical associations that depend on various modes of molecular communication for their development and functioning. These bacterial-fungal interactions often result in changes to the pathogenicity or the nutritional influence of one or both partners toward plants or animals (including humans). They can also result in unique contributions to biogeochemical cycles and biotechnological processes. Thus, the interactions between bacteria and fungi are of central importance to numerous biological questions in agriculture, forestry, environmental science, food production, and medicine. Here we present a structured review of bacterial-fungal interactions, illustrated by examples sourced from many diverse scientific fields. We consider the general and specific properties of these interactions, providing a global perspective across this emerging multidisciplinary research area. We show that in many cases, parallels can be drawn between different scenarios in which bacterial-fungal interactions are important. Finally, we discuss how new avenues of investigation may enhance our ability to combat, manipulate, or exploit bacterial-fungal complexes for the economic and practical benefit of humanity as well as reshape our current understanding of bacterial and fungal ecology.

A novel fingerprint method to assess the diversity of methanogens in microbial systems

Understanding the ecology of methanogens in natural and engineered environments is a prerequisite to predicting or managing methane emissions. In this study, a novel high-throughput fingerprint method was developed for determining methanogen diversity and relative abundance within environmental samples. The method described here, designated amplicon length heterogeneity PCR of the mcrA gene (LH-mcrA), is based on the natural length variation in the mcrA gene. The mcrA gene encodes the alpha-subunit of the methyl-coenzyme M reductase, which is involved in the terminal step of methane production by methanogens. The methanogenic communities from stored swine and dairy manures were distinct from each other. To validate the method, methanogenic communities in a plug flow-type bioreactor (PFBR) treating swine manure were characterized using LH-mcrA method and correlated to mcrA gene clone libraries. The diversity and relative abundance of the methanogenic groups were assessed. Methanobrevibacter, Methanosarcinaceae, Methanoculleus, Methanogenium, Methanocorpusculum and one unidentified group were assigned to particular LH-mcrA amplicons. Particular phylotypes related to Methanoculleus were predominant in the last compartment of the PFBR where the bulk of methane was produced. LH-mcrA method was found to be a reliable, fast and cost-effective alternative for diversity assessment of methanogenic communities in microbial systems.

Influence of feed characteristics on the removal of micropollutants during the anaerobic digestion of contaminated sludge

The removal of 13 polycyclic aromatic hydrocarbons, 7 polychlorobiphenyls and nonylphenol was measured during the continuous anaerobic digestion of five different sludge samples. The reactors were fed with one of the following: primary/secondary sludge (PS/SS), thermally treated PS, cellulose-added SS, or SS augmented with dissolved and colloidal matter (DCM). These various feeding conditions induced variable levels of micropollutant bioavailability (assumed to limit their biodegradation) and overall metabolism (supposed to be linked to micropollutant metabolism throughout co-metabolism). On the one hand, overall metabolism was higher with secondary sludge than with primary and the same was observed for micropollutant removal. However, when overall metabolism was enhanced thanks to cellulose addition, a negative influence on micropollutant removal was observed. This suggests that either the co-metabolic synergy would be linked to a specific metabolism or co-metabolism was not the limiting factor in this case. On the other hand, micropollutant bioavailability was presumably diminished by thermal treatment and increased by DCM addition. In both cases, micropollutant removal was reduced. These results suggest that neither overall metabolism nor bioavailability would absolutely limit micropollutant removal. Each phenomenon might alternatively predominate depending on the feed characteristics.

PAH fate during the anaerobic digestion of contaminated sludge: Do bioavailability and/or cometabolism limit their biodegradation?

The anaerobic removal of 13 Polycyclic Aromatic Hydrocarbons (PAHs) was measured in five continuous anaerobic digestors with different feed sludge, in which abiotic losses were neglected. These feeds were chosen to generate different levels of PAH bioavailability and cometabolism within the reactors. Based on the accurate modelling of PAH sorption in sludge, the aqueous fraction (including free and sorbed-to-dissolved-and-colloidal-matter PAHs) was demonstrated to be bioavailable, which validated a widespread assumption about micropollutants bioavailability in sludge. It was also demonstrated that bioavailability is not the only influencing factor. Indeed, PAHs biodegradation resulted from a combination of bioavailability and cometabolism. An equation adapted from Criddle (1993, The Kinetics of Cometabolism. Biotechnology and Bioengineering 41, 1048-1056) that takes into account both mechanisms was shown to fit the experimental data, with dry matter removal rate identified as the criteria for cometabolism. The existence of a threshold of dry matter cometabolism was suggested, below which PAHs removal would not be possible. The parameters of the Criddle equation were demonstrated to depend on PAH molecular structure, and the results suggest that they would also be influenced by substrate composition and microbial population. This research provided original outcomes for the assessment of micropollutants fate. Indeed, the understanding of the driving mechanisms was improved, which has implications for the optimization of micropollutants removal.

Micropollutant and sludge characterization for modeling sorption equilibria

The sorption of hydrophobic micropollutants in sludge is one of the major mechanisms which drive their fate within wastewater treatment systems. The objective of this study was to investigate the influence of both sludge and micropollutant characteristics on the equilibria of sorption to particles and to dissolved and colloidal matter (DCM). For this purpose, the equilibrium constants were measured for 13 polycyclic aromatic hydrocarbons, 5 polychlorobiphenyls and the nonylphenol, and five different sludge types encountered in treatment systems: a primary sludge, a secondary sludge, the same secondary sludge after thermal treatment, after anaerobic digestion, and after both treatments. After thermal treatment, no more sorption to DCM was observed. Anaerobic biological treatment was shown to enhance micropollutants sorption to particles and to DCM of one logarithmic unit, due to matter transformation. Partial least-squares linear regressions of sorption data as a function of micropollutant and sludge properties revealed that sludge physical and chemical characteristics were more influential than micropollutant characteristics. Two models were provided to predict the sorption of such micropollutants in any sludge. To our knowledge, this is the first time that a three-compartment approach is used to accurately model micropollutant sorption in sludge and to understand the driving mechanisms.

A three-compartment model for micropollutants sorption in sludge: methodological approach and insights

In sludge resulting from wastewater treatment, organic micropollutants sorb to particles and to dissolved/colloidal matter (DCM). Both interactions may influence their physical and biological fate throughout the wastewater treatment processes. To our knowledge, sludge has never been considered as a three-compartment matrix, in which micropollutants coexist in three states: freely dissolved, sorbed-to-particles and sorbed-to-DCM. A methodology is proposed to concomitantly determine equilibrium constants of sorption to particles (K(part)) and to DCM (K(DCM)). Polycyclic Aromatic Hydrocarbons (PAHs) were chosen as model compounds for the experiments. The logarithm of estimated equilibrium constants ranged from 3.1 to 4.3 and their usual correlation to PAH hydrophobicity was verified. Moreover, PAH affinities for particles and for DCM could be compared. Affinity for particles was found to be stronger, probably due to their physical and chemical characteristics. This work provided a useful tool to assess the freely dissolved, sorbed-to-particles and sorbed-to-DCM concentrations of contaminants, which are necessary to accurately predict their fate. Besides, guidelines to investigate the link between sorption and the fundamental concept of bioavailability were proposed.

Preclinical identification of biomarkers of response to mTOR inhibitors and subsequent application in a phase II trial of sirolimus in pancreatic cancer patients refractory to gemcitabine

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Background: Treatment for advanced pancreatic cancer refractory to gemcitabine has not been defined. We conducted an efficacy study in pancreatic cancer xenografts to identify biomarkers of response to mTOR inhibition and attempted to translate the results by conducting a phase II trial of sirolimus in this patient population. Methods: 19 direct pancreatic xenografts were treated with temsirolimus (20mg/Kg IP daily) for 28 days. Tumors were profiled with array CGH and gene expression arrays at baseline. TGI were calculated at 28 days. Patients refractory to gemcitabine were included in the clinical trial. Sirolimus was administered at 5mg/day for 28 days. Primary endpoint was 6 month survival rate (6mSR). Secondary endpoints included: baseline evaluation of AKT pathway activation, pharmacodynamic assessment of p-S6K in PBMC, pharmacokinetics and toxicity analysis. Results: In the preclinical study, mTOR sensitive tumors showed upregulation of genes involved in the renal cell cancer pathway. CGH identified focal gains in N-Ras and K-Ras and homozygous deletions of FHIT in sensitive cases. Overall, these genetic changes induced AKT pathway activation, and led us to explore high baseline p-S6K expression as a predictor of outcome in the clinical phase. Patient characteristics: Median age: 64 (39–77). 11 patients had received ≥ 2 prior lines of chemotherapy. 6mSR was 20%. 6mSR in the subgroup of patients who received rapamycin as first line chemotherapy after progression to gemcitabine was 34%. Baseline tumor p-S6K was not predictive for survival. Early pharmacodynamic changes in p-S6K in PBMC 6 hours after treatment initiation were correlated with survival (R2= 0.65). Treatment was well tolerated. The most common grade 3 adverse event was hyperglycemia in 10% of the patients. 7 (23%) patients achieved stable disease. Conclusions: Rapamycin is well tolerated in this setting. Early pharmacodynamic changes in p-S6K in PBMC were correlated with survival. Preclinical findings leading to activation of the AKT pathway in all sensitive cases warrants further validation studies. Efficacy data is limited by the selection of a heavily pretreated and poor prognosis population (DFS≤47 days).

No significant financial relationships to disclose.

The plant pathogenic fungus Gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain Pseudomonas fluorescens Pf29Arp

In soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. Direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. An in vitro confrontation bioassay between the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) and the biocontrol bacterial strain Pseudomonas fluorescens Pf29Arp was set up to analyse bacterial transcriptional changes induced by the fungal mycelium at three time-points of the interaction before cell contact and up until contact. For this, a Pf29Arp shotgun DNA microarray was constructed. Specifity of Ggt effect was assessed in comparison with one of two other filamentous fungi, Laccaria bicolor and Magnaporthe grisea. During a commensal interaction, Ggt increased the growth rate of Pf29Arp. Before contact, Ggt induced bacterial genes involved in mycelium colonization. At contact, genes encoding protein of stress response and a patatin-like protein were up-regulated. Among all the bacterial genes identified, xseB was specifically up-regulated at contact by Ggt but down-regulated by the other fungi. Data showed that the bacterium sensed the presence of the fungus early, but the main gene alteration occurred during bacterial-fungal cell contact.

Reduced levels of uridine diphosphate glucose pyrophosphorylase activity in fetal and neonatal human and guinea pig liver

Uridine diphosphate glucose pyrophosphorylase (UDPGPP) is the first enzyme in the bilirubin conjugation pathway. A study aiming to screen for red blood cell UDPGPP deficiency in newborns with hyperbilirubinemia was carried out. No individuals with severe UDPGPP deficiency were found, however, levels of UDPGPP in premature and at term newborns were lower than in adults. These findings led to the study of UDPGPP in human fetal, neonatal and adult liver, using guinea pig tissues as a parallel control. UDPGPP activities in fetal and neonatal samples were also significantly lower than in adult ones in both species. Therefore, it is postulated that the reduced levels of UDPGPP in fetal and neonatal liver could be a factor which contributes to the pathogenesis of the physiologic jaundice in human newborns.