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Campylobacter is the most common cause of foodborne bacterial illness worldwide. Faecal contamination of meat, especially chicken, during processing represents a key route of transmission to humans. There is a lack of insight into the mechanisms driving C. jejuni growth and survival within hosts and the environment. Here, we report a detailed analysis of C. jejuni fitness across models reflecting stages in its life cycle. Transposon (Tn) gene-inactivation libraries were generated in three C. jejuni strains and the impact on fitness during chicken colonisation, survival in houseflies and under nutrient-rich and -poor conditions at 4 °C and infection of human gut epithelial cells was assessed by Tn-insertion site sequencing (Tn-seq). A total of 331 homologous gene clusters were essential for fitness during in vitro growth in three C. jejuni strains, revealing that a large part of its genome is dedicated to growth. We report novel C. jejuni factors essential throughout its life cycle. Importantly, we identified genes that fulfil important roles across multiple conditions. Our comprehensive screens showed which flagella elements are essential for growth and which are vital to the interaction with host organisms. Future efforts should focus on how to exploit this knowledge to effectively control infections caused by C. jejuni.

Campylobacter is the most common cause of foodborne bacterial illness worldwide. Faecal contamination of meat, especially chicken, during processing represents a key route of transmission to humans. There is a lack of insight into the mechanisms driving C. jejuni growth and survival within hosts and the environment. Here, we report a detailed analysis of C. jejuni fitness across models reflecting stages in its life cycle. Transposon (Tn) gene-inactivation libraries were generated in three C. jejuni strains and the impact on fitness during chicken colonisation, survival in houseflies and under nutrient-rich and -poor conditions at 4 °C and infection of human gut epithelial cells was assessed by Tn-insertion site sequencing (Tn-seq). A total of 331 homologous gene clusters were essential for fitness during in vitro growth in three C. jejuni strains, revealing that a large part of its genome is dedicated to growth. We report novel C. jejuni factors essential throughout its life cycle. Importantly, we identified genes that fulfil important roles across multiple conditions. Our comprehensive screens showed which flagella elements are essential for growth and which are vital to the interaction with host organisms. Future efforts should focus on how to exploit this knowledge to effectively control infections caused by C. jejuni.

Genetic variation due to mutation and phase variation has a considerable impact on the commensal and pathogenic behaviours of Campylobacter jejuni. In this study, we provide an example of how second-site mutations can interfere with gene function analysis in C. jejuni. Deletion of the flagellin B gene (flaB) in C. jejuni M1 resulted in mutant clones with inconsistent motility phenotypes. From the flaB mutant clones picked for further analysis, two were motile, one showed intermediate motility and two displayed severely attenuated motility. To determine the molecular basis of this differential motility, a genome resequencing approach was used. Second-site mutations were identified in the severely attenuated and intermediate motility flaB mutant clones: a TA-dinucleotide deletion in fliW and an A deletion in flgD, respectively. Restoration of WT fliW, using a newly developed genetic complementation system, confirmed that the second-site fliW mutation caused the motility defect as opposed to the primary deletion of flaB. This study highlights the importance of (i) screening multiple defined gene deletion mutant clones, (ii) genetic complementation of the gene deletion and ideally (iii) screening for second-site mutations that might interfere with the pathways/mechanisms under study.

Sulphide-rich tailings constitute a major environmental concern due to the acid drainage (AD) production and release of potentially toxic elements (PTE). Therefore, the management of active mine dumps and the reclamation of inactive ones require to reduce the exposure of the possible environmental receptors to contamination. A common, critical feature of mine dumps is the heterogeneity of the tailing materials that may complicate the quantitative prediction of potential contamination. On the other hand, heterogeneity can be a key for a more rational and cost-effective remediation, given a good characterization of the dump materials. Moreover, mine wastes often contain valuable components and therefore a suitable solution is to make positive use of them. In fact, as mining and processing (comminution and concentration) constitute a major cost of the ore mineral cycle, the availability of partly-processed, although low-grade resources may represent an interesting opportunity of exploitation. The present work is a case-study for a quantitative flow-sheet-related approach to the aim of heterogeneous sulphide-rich tailing dumps management. We selected the former processing site of Reps, in the Mirdita District (northern Albania), where we characterized two tailing dumps and assessed the contamination. Moreover, we evaluated the concentration potential of commodities, namely pyrite and gold, from the tailing materials. We analysed the Reps tailing samples in order to evaluate mineralogy, grain size and bulk chemical composition, concentration of PTE, the presence and persistence of AD. The data set splits in two classes, based on the sulphide content. The reconstruction of the former processing flow-sheet allowed us to recognize this pattern as resulting from two distinct processing stages and to quantitatively improve the AD prediction results. We selected a shaking table concentration method for testing separation of pyrite and gold, by taking into consideration the nee

Cleft lip with or without cleft palate (CL/P) is a complex trait with evidence that the clinical spectrum includes both microform and subepithelial lip defects. We identified missense and nonsense mutations in the BMP4 gene in 1 of 30 cases of microform clefts, 2 of 87 cases with subepithelial defects in the orbicularis oris muscle (OOM), 5 of 968 cases of overt CL/P, and 0 of 529 controls. These results provide confirmation that microforms and subepithelial OOM defects are part of the spectrum of CL/P and should be considered during clinical evaluation of families with clefts. Furthermore, we suggest a role for BMP4 in wound healing. © 2009 The American Society of Human Genetics.

Contains fulltext : 69885.pdf (publisher's version ) (Closed access), AIM AND METHOD: We analysed DNA samples isolated from individuals born with cleft lip and cleft palate to identify deletions and duplications of candidate gene loci using array comparative genomic hybridisation (array-CGH). RESULTS: Of 83 syndromic cases analysed we identified one subject with a previously unknown 2.7 Mb deletion at 22q11.21 coinciding with the DiGeorge syndrome region. Eighteen of the syndromic cases had clinical features of Van der Woude syndrome and deletions were identified in five of these, all of which encompassed the interferon regulatory factor 6 (IRF6) gene. In a series of 104 non-syndromic cases we found one subject with a 3.2 Mb deletion at chromosome 6q25.1-25.2 and another with a 2.2 Mb deletion at 10q26.11-26.13. Analyses of parental DNA demonstrated that the two deletion cases at 22q11.21 and 6q25.1-25.2 were de novo, while the deletion of 10q26.11-26.13 was inherited from the mother, who also has a cleft lip. These deletions appear likely to be causally associated with the phenotypes of the subjects. Estrogen receptor 1 (ESR1) and fibroblast growth factor receptor 2 (FGFR2) genes from the 6q25.1-25.2 and 10q26.11-26.13, respectively, were identified as likely causative genes using a gene prioritization software. CONCLUSION: We have shown that array-CGH analysis of DNA samples derived from cleft lip and palate subjects is an efficient and productive method for identifying candidate chromosomal loci and genes, complementing traditional genetic mapping strategies.

The structure and basic properties of graphite are reviewed. Natural graphite is mined from ore containing 3-20% graphite which is subjected to wet grinding to liberate graphite flakes, followed by flotation and drying and classification of the flakes. Higher purity is achieved through chemical purification by leaching with hydrofluoric and hydrochloric acid or by hydration with caustic soda followed by hydrochloric acid leaching. Purification can also be achieved by thermal treatment at above 2 000 degrees C. Synthetic graphite is obtained from carbon precursors such as petroleum and coal tar-based cokes which are graphitised by heat treatment at above 2 500 degrees C in the absence of oxygen. Graphite powders are produced by ball, mechanical, hammer or jet mills. Fine particles are produced using air classifiers. Additional processing is required for shape surface modification. Expanded graphite is produced by subjecting intercalated natural graphite flakes to thermal shock. Applications of graphite include batteries, fuel cells, friction materials, carbon brushes, lubricants in tribology, thermally conductive polymers and refractories., The structure and basic properties of graphite are reviewed. Natural graphite is mined from ore containing 3-20% graphite which is subjected to wet grinding to liberate graphite flakes, followed by flotation and drying and classification of the flakes. Higher purity is achieved through chemical purification by leaching with hydrofluoric and hydrochloric acid or by hydration with caustic soda followed by hydrochloric acid leaching. Purification can also be achieved by thermal treatment at above 2 000 degrees C. Synthetic graphite is obtained from carbon precursors such as petroleum and coal tar-based cokes which are graphitised by heat treatment at above 2 500 degrees C in the absence of oxygen. Graphite powders are produced by ball, mechanical, hammer or jet mills. Fine particles are produced using air classifiers. Additional processing is required for shape surface modification. Expanded graphite is produced by subjecting intercalated natural graphite flakes to thermal shock. Applications of graphite include batteries, fuel cells, friction materials, carbon brushes, lubricants in tribology, thermally conductive polymers and refractories.