Simultaneous growth of two cancer cell lines evidences variability in growth rates

Cancer cells co-cultured in vitro reveal unexpected differential growth rates that classical exponential growth models cannot account for. Two non-interacting cell lines were grown in the same culture, and counts of each species were recorded at periodic times. The relative growth of population ratios was found to depend on the initial proportion, in contradiction with the traditional exponential growth model. The proposed explanation is the variability of growth rates for clones inside the same cell line. This leads to a log-quadratic growth model that provides both a theoretical explanation to the phenomenon that was observed, and a better fit to our growth data

Draft Genome Sequence of the Flagellated Xanthomonas fuscans subsp. fuscans Strain CFBP 4884

Article de revue (Article scientifique dans une revue à comité de lecture)International audienceWe report the draft genome sequence of the flagellated strain CFBP 4884 of Xanthomonas fuscans subsp. fuscans, which was isolatedin an outbreak of common bacterial blight of beans along with non-flagellated strains. Comparative genomics will allowone to decipher the genomic diversity of strains cohabiting in epidemics.</p

Le lexique scientifique transdisciplinaire : une introduction

International audienc

Pest categorisation of Acrobasis pirivorella

The European Commission requested EFSA to conduct a pest categorisation of Acrobasis pirivorella (Lepidoptera: Pyralidae), a monophagous moth whose larvae exclusively feed on developing buds, flowers, and fruits of cultivated and wild Pyrus spp. A. pirivorella is a species with reliable methods available for identification. A. pirivorella occurs in north-east Asia only, causing significant damage in cultivated pears. It is regulated in the EU by Council Directive 2000/29/EC where it is listed in Annex IIAI. Within this regulation, plants for planting of Pyrus spp. is a closed pathway. This species has never been reported by Europhyt. Fruits and cut branches of Pyrus spp. are open pathways. Biotic and abiotic conditions are conducive for establishment and spread of A. pirivorella in the EU. Were A. pirivorella to establish, impact on pear production is expected. Considering the criteria within the remit of EFSA to assess its regulatory plant health status, A. pirivorella meets the criteria for consideration as a potential Union quarantine pest (it is absent from the EU, potential pathways exist and its establishment would cause an economic impact). Given that A. pirivorella is not known to occur in the EU, it fails to meet some of the criteria required for regulated non-quarantine pest (RNQP) status

Towards real-time metabolic profiling of a biopsy specimen during a surgical operation by 1H high resolution magic angle spinning nuclear magnetic resonance: a case report

<p>Abstract</p> <p>Introduction</p> <p>Providing information on cancerous tissue samples during a surgical operation can help surgeons delineate the limits of a tumoral invasion more reliably. Here, we describe the use of metabolic profiling of a colon biopsy specimen by high resolution magic angle spinning nuclear magnetic resonance spectroscopy to evaluate tumoral invasion during a simulated surgical operation.</p> <p>Case presentation</p> <p>Biopsy specimens (n = 9) originating from the excised right colon of a 66-year-old Caucasian women with an adenocarcinoma were automatically analyzed using a previously built statistical model.</p> <p>Conclusions</p> <p>Metabolic profiling results were in full agreement with those of a histopathological analysis. The time-response of the technique is sufficiently fast for it to be used effectively during a real operation (17 min/sample). Metabolic profiling has the potential to become a method to rapidly characterize cancerous biopsies in the operation theater.</p

Pest categorisation of Aleurocanthus spp

The Panel on Plant Health performed a pest categorisation of Aleurocanthus spp., a well-de fi ned insect genus of the white fl y family Aleyrodidae (Arthropoda: Hemiptera). Dif fi culties within the taxonomy of the genus give doubt about the ability to accurately identify some members to species level. Nevertheless, the genus is thought to currently include about ninety species mainly reported from tropical and subtropical areas. The genus is listed in Council Directive 2000/29/EC and is regulated on Citrus, Fortunella and Poncirus . Several Aleurocanthu s species are highly polyphagous; Aleurocanthu s spiniferus has hosts in 38 plant families; Aleurocanthu s woglumi has more than 300 hosts including Pyrus , Rosa and Vitis vinifera as well as Citrus . A. spiniferus is present in the EU in restricted areas of Italy and Greece, where it is under of fi cial control. No other Aleurocanthus spp. are known to occur in the EU. Host plants for planting, excluding seeds, and cut fl owers or branches are the main pathways for entry. Outside of the EU, the genus can be found in regions that have climate types which also occur within the EU, suggesting establishment is possible. Aleurocanthus spp. can be signi fi cant pests of crops that are also grown in the EU. Phytosanitary measures are available to reduce the likelihood of entry into the EU, e.g. sourcing host plants for planting from pest free areas. As a genus Aleurocanthus does satisfy all the criteria that are within the remit of EFSA to assess and required by risk managers to give it consideration as a Union quarantine pest. Aleurocanthus does not meet all of the criteria to allow it consideration by risk managers as a Union regulated non-quarantine pest (RNQP). Speci fi cally, Aleurocanthus is not widespread in the EU

Pest categorisation of Stagonosporopsis andigena.

The Panel on Plant Health performed a pest categorisation of Stagonosporopsis andigena, the causal agent of black blight of potato, for the EU. The pest is a well-defined fungal species and reliable methods exist for its detection and identification. S. andigena is present in Bolivia and Peru. The pest is not known to occur in the EU and is listed in Annex IAI of Directive 2000/29/EC as Phoma andina, meaning its introduction into the EU is prohibited. The major cultivated host is Solanum tuberosum (potato); other tuber-forming Solanum species and wild solanaceous plants are also affected. All hosts and pathways of entry of the pest into the EU are currently regulated. Host availability and climate matching suggest that S. andigena could establish in parts of the EU and further spread mainly by human-assisted means. The pest affects leaves, stems and petioles of potato plants causing lesions and premature leaf drop but not the underground parts, including tubers. The disease causes yield reductions up to 80%, depending on the susceptibility of potato cultivars. Early application of fungicide sprays and cultivation of resistant potato cultivars are the most effective measures for disease management. The pest introduction in the EU would potentially cause impacts to potato production. The main uncertainties concern the host range, the maximum period the pest survives on host debris in soil, the maximum distance over which conidia of the pest could be dispersed by wind-blown rain, and the magnitude of potential impacts to the EU. S. andigena meets all the criteria assessed by EFSA for consideration as potential Union quarantine pest. The criteria for considering S. andigena as a potential Union regulated non-quarantine pest are not met, since the pest is not known to occur in the EU

Pest categorisation of Thecaphora solani

The Panel on Plant Health performed a pest categorisation of the fungus Thecaphora solani, the causal agent of smut of potato, for the EU. The identity of the pest is well established and reliable methods exist for its detection and identification. T. solani is present in Bolivia, Chile, Colombia, Ecuador, Mexico, Panama, Peru and Venezuela. The pathogen is not known to occur in the EU and is listed in Annex IAI of Directive 2000/29/EC, meaning its introduction into the EU is prohibited. The major host is Solanum tuberosum (potato), but various other tuber-forming Solanum species are also affected. The pest has also been reported on Solanum lycopersicum (tomato), and wild solanaceous plants are also affected. All the major hosts and pathways of entry are currently regulated. Host availability and climate matching suggest that T. solani could establish in parts of the EU and further spread by human-assisted means. The disease induces gall formation on potato tubers, stolons and underground stem parts, reducing yield and making tubers unmarketable. The pest introduction in the EU would potentially cause impacts to potato production. In the infested areas, the only available strategy to control the disease and prevent it from spreading is the application of quarantine and sanitation measures and the cultivation of resistant varieties. The main uncertainties concern the host range, the biology and epidemiology of the pest, and the potential of the pest to enter the EU through three unregulated minor pathways. T. solani meets all the criteria assessed by EFSA for consideration as potential Union quarantine pest. The criteria for considering T. solani as a potential Union regulated non-quarantine pest are not met, since the pest is not known to occur in the EU

A novel molecular typing system for pathogenic xanthomonads

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated sequences (cas) form hypervariable loci which are widely distributed in prokaryotes. The repetitive region is characterized by short interspersed unique spacer sequences which often match to bacteriophagederived DNA, thus providing immunity against foreign genetic elements, in particular bacteriophages. Bacteria of the genus Xanthomonas cause diseases on over 400 different host plants, including many economically important crops, such as rice, wheat, citrus, and banana plants. We screened more than 300 strains of Xanthomonas, representing ten different species (44 pathovars), for the presence of CRISPR loci. Only a few pathovars were found to possess a CRISPR locus, among them X. axonopodis pv. vasculorum, X. axonopodis pv. cassavae, X. campestris pv. raphani, X. citri pv. citri, X. oryzae pv. oryzae (Xoo), X. translucens, and X. vasicola pv. musacearum. Presence/absence of CRISPR loci appeared to be conserved at the pathovar level, except for Xoo. The apparent absence of CRISPR loci from African Xoo isolates confirms previous results showing that African Xoo isolates form a phylogenetic group that is distant from the Asian Xoo group. Comparative genomics suggested that the common ancestor of all xanthomonads had two CRISPR loci which in most species/pathovars got lost during evolution. Based on DNA sequence information about the terminal spacers of 32 Asian Xoo CRISPR loci we postulate that the common ancestor of these strains had all the spacers which are nowadays still found in a few strains and that some spacers got lost during evolution in some Xoo lineages. This work represents the first proof of concept of CRISPR analysis as a molecular tool for high-resolution strain typing, phylogenetic studies, and global surveillance of a phytopathogen

Pest categorisation of Popillia japonica.

The Panel on Plant Health performed a pest categorisation of Popillia japonica (Coleoptera: Scarabaeidae) for the EU. P. japonica is a distinguishable species listed in Annex IAII of Council Directive 2000/29/EC. It is native to Japan but established in the USA in the early 20th century. It spreads from New Jersey to most US states east of the Mississippi, some to the west and north into Canada. P. japonica feeds on over 700 plant species. Adults attack foliage and fruit surfaces. They can cause serious injury to tree fruits and soft fruit, vegetable crops, ornamental herbaceous plants, shrubs, vines and trees. Larvae are root feeders regarded as serious pests of lawns and turf, vegetables and nursery stock. Adults emerge during the summer and can fly short distances on warm sunny days. The life cycle is usually completed in one year. In cooler regions, development takes two years. P. japonica occurs in the EU in the Azores (Portugal), Lombardy and Piedmont (Italy) where it is under official control. Adults are suspected of being able to spread on aircraft as hitchhikers, i.e. without host plants. Soil accompanying plants for planting provides a pathway for further introductions. Hosts are widely available within the EU. Climatic conditions across central and parts of southern EU are suitable for development in one year. Across parts of northern Europe development over two years is likely. Without control, impacts could be expected on a range of plants. Phytosanitary measures are available to reduce the likelihood of introduction of P. japonica. All criteria assessed by EFSA for consideration as a potential Union quarantine pest are met. Plants for planting are not necessarily the main means of spread so P. japonica does not satisfy all criteria necessary for it to be regarded as a Union regulated non-quarantine pest (RNQP)