Anisotropy in the helicity modulus of a quantum 3D XY-model: application to YBCO

We present a variational study of the helicity moduli of an anisotropic quantum three-dimensional (3D) XY-model of YBCO in superconducting state. It is found that both the ab-plane and the c-axis helicity moduli, which are proportional to the inverse square of the corresponding magnetic field penetration depth, vary with temperature T as T to the fourth power in the zero temperature limit. Moreover, the c-axis helicity modulus drops with temperature much faster than the ab-plane helicity modulus because of the weaker Josephson couplings along the c-axis compared to those along the ab-plane. These findings are in disagreement with the experiments on high quality samples of YBCO.Comment: 9 pages, 1 figur

The cpn60 gene as an additional marker for 'Candidatus Phytoplasma asteris' strain differentiation.

The phytoplasma classification was firstly established using RFLP analysis with a number of restriction enzymes on 1,200 bp amplicons in their 16S rDNA. Obtained phytoplasma 16Sr groups have been shown to be consistent with the groups (clades) defined by phylogenetic analysis of near-full-length 16S rRNA gene sequences, confirming phylogenetical validity of this grouping. However the recent introduction of \u2018Candidatus\u2019 status, which is based on 16S sequences, does not always provides the molecular distinction necessary for epidemiological studies towards disease control. For \u2018Candidatus Phytoplasma asteris\u2019-related phytoplasmas numerous different diseases, plant species and insect vectors were described and attributed to different 16SrI subgroups. However because of the highly conserved nature of the 16S rRNA gene, and of the not uncommon presence of 16S rDNA interoperon sequence heterogeneity, more variable single copy genes were often shown to be more suitable for finer phytoplasma differentiation. Additional genes such as ribosomal protein (rp), secY, tuf, have been used for \u2018Ca. P. asteris\u2019-related strains differentiation corroborating the 16S rDNA designed subgroups. Several publically available sequences of the 3.6 kb phytoplasma fragments, containing cpn10, cpn60, amp and nadE genes allowed design of primers for specific amplification of 1,397 bp fragments containing phytoplasma cpn60 gene. Variability of amplified sequences was then studied in 27 \u2018Ca. P. asteris\u2019-related strains belonging to different 16SrI subgroups. The RFLP analyses of the amplified fragment with TruI and AluI restriction enzymes confirmed the reported differentiation among 16SrI-A, I-B, I-C, I-F and I-P subgroups, and showed further differentiation in strains assigned to 16SrI-A, 16SrI-B and 16SrI-C subgroups. However, analyses of cpn60 gene failed to discriminate strains in subgroups 16SrI-L and 16SrI-M (described on the basis of 16S rDNA interoperon heterogeneity) from strains in subgroup 16SrI-B, as it was also shown on tuf and rp genes. On the contrary, the 16SrI unclassified strain ca2006/5 from carrot (showing interoperon heterogeneity) was differentiable on both rp and cpn60 genes from the strains in subgroup 16SrI-B. These results indicate that interoperon sequence heterogeneity of strains AY2192, and PRIVA (16SrI-L), AVUT (16SrI-M), and ca2006/5 resulted in multigenic changes - one evolutionary step further - only in the latter case. Phylogenetic analyses carried out on full cpn60 gene (1,610 bp) are in agreement with 16Sr-based phylogeny, and confirmed also the further differentiation detected by RFLP analyses on specifically amplified and sequenced 1,397 bp fragments. Maximum sequence variability among the 16SrI group examined strains was 6.2% mismatches in cpn60 gene, while maximum reported sequence variability among the same phytoplasmas was 2.6% for 16S rDNA, 3.6% for tuf and 3.2% for rp genes

Caratterizzazione molecolare di \u2018Candidatus Phytoplasma asteris\u2019 in ortensia in Canada

Hydrangea species are infected by phytoplasmas belonging to subgroups 16SrI-A and 16SrI-B (aster yellows) inducing phyllody and virescence worldwide. In Japan some of the phytoplasma associated such disease were classified as \u2018Candidatus Phytoplasma japonicum\u2019, moreover 16SrXII-A phytoplasmas were identified in Bulgaria and more recently in Italy. The hydrangea phyllody disease was associated with 16SrI-B phytoplasmas in Canada, however no fine molecular characterization was carried out on the phytoplasmas in that country. Hydrangeas showing symptoms similar to those associated with phytoplasma diseases were found and collected from landscape areas in South-western Ontario, Canada. Phytoplasmas belonging aster yellows group were detected in all symptomatic samples tested by two different methodologies. Direct sequencing and sequence obtained after cloning of the 16Sr DNA gene show confirmation of reported classification and the amplification and sequencing of groEL gene confirm previous classification in subgroup 16SrI-B and allow to enclose aster yellows phytoplasmas in hydrangeas from Canada in the groELI-III group that up to now was only detected in Europe

GroEL gene characterization of \u201cbois noir\u201d phytoplasma from Serbia, Bulgaria and Italy

Stolbur phytoplasma belongs to ribosomal subgroup 16SrXII-A and is associated with \u2018bois noir\u2019 disease of grapevine. Sequence and RFLP analyses of 16S rDNA of stolbur phytoplasma show small or no variability among the strains that originate from different parts of the world (Garnier, 2000). However there are reports of molecular variability in other genes such as tuf, vmp1, stamp and secY genes (Pacifico et al., 2007; Cimerman et al., 2009; Fabre et al., 2011). So far, tuf gene is the only gene for which it has been shown that is related to specific herbaceous host and a vector population (Langer and Maixner, 2004). Encoded gene for large subunit of molecular chaperonin (groEL gene) has already been used as molecular marker for better identification of some bacterial species such as Salmonella and Staphylococcus, or for characterization of different serotypes of Streptococcus suis (Goh, 1996; Satheesh, 2002; Brousseau i sar., 2001). In previous reports, RFLP analysis of groEL gene was shown to be a useful tool in characterization of aster yellows strains and stolbur phytoplasma from different plant hosts (Mitrovi\u107 et al., 2011; Mitrovi\u107 and Duduk 2012). Therefore, variability of groEL gene of previously identified BN strains from Serbia, Bulgaria and Italy was investigated

The use of groEL gene in characterisation of aster yellows phytoplasmas in field collected samples

Amplification of fragments containing phytoplasma groEL gene sequence with a newly designed nested PCR system allowed to specifically detect the presence of \u2018Candidatus Phytoplasma asteris\u2019 in reference strains as well as in samples field collected and maintained as dry/freeze dried nucleic acids. After RFLP analyses it was possible to confirm further finer differentiation in strains enclosed in subgroup 16SrI-B by previous ribosomal gene classification

The use of groEL gene in characterisation of aster yellows phytoplasmas in field collected samples

Amplification of fragments containing phytoplasma groEL gene sequence with a newly designed nested PCR system allowed to specifically detect the presence of \u2018Candidatus Phytoplasma asteris\u2019 in reference strains as well as in samples field collected and maintained as dry/freeze dried nucleic acids. After RFLP analyses it was possible to confirm further finer differentiation in strains enclosed in subgroup 16SrI-B by previous ribosomal gene classification

Identifying potential phytoplasma vectors in infected carrot fields in Serbia.

Aster yellows (AY) phytoplasmas have been reported for the first time in Serbia in carrots showing yellows symptoms (Duduk et al., Bulletin of Insectology 60, 341-342. 2007). To prevent further dangerous spreading of the disease, identification of the insect species possibly vectoring this phytoplasma and detection insect-carried phytoplasmas were carried out. During 2007 and 2008 leafhoppers were trapped from the beginning of April to the end of October, in two sites in the South Ba\u10dka region of Serbia, where phytoplasma associated diseases were reported although in low percentages (about 3%). Adult leafhoppers were sampled at two-week intervals, in carrot fields and weeds nearby, by using double-sided, yellow sticky traps (25x10) and by sweep netting in both sites. Leafhoppers were stored in 96% ethanol and identified before extraction of nucleic acids. Phytoplasma detection in identified species was carried out by nested PCR-RFLP assays on 16S ribosomal gene. The presence of four known vectors of AY phytoplasmas was recorded: Anaceratagallia laevis (Ribaut), Macrosteles laevis (Ribaut), M. quadripunctulatus (Kirschbaum) and M. sexnotatus (Fallen). Other six leafhopper species, which are not known, according to literature, as AY vectors i.e. Anaceratagallia ribauti (Ossiannilsson), A. venosa (Fourcroy), Empoasca spp., Scaphoideus titanus (Ball), Psammotettix alienus (Dahlbom), P. striatus (Linnaeus) were identified. The other five identified species, Eupteryx mellissae (Curtis), Ophiola decumana (Kontkanen), Psammotettix confinis (Dahlbom), P. notatus (Melichar) and Errastanus ocellaris (Fall\ue9n), are not known described as vectors. AY phytoplasmas were detected in the following vector and non-vector leafhopper species: A. laevis, A. ribauti, M. quadripunctulatus, M. sexnotatus, O. decumana and P. confinis. Transmission experiments with previously unreported vector species are in progress to provide evidence of their vector abilities

Efficiency and selectivity of ionic liquids in microwave-assisted extraction of major lichen phenolic compounds: a scalable process with recycling of ionic liquids

International audienceINTRODUCTION: Pseudevernia furfuracea, a lichen used classically for cosmetic applications, contains interesting metabolites possessing antimicrobial and anti-inflammatory or antioxidant properties. OBJECTIVES: Ionic liquid combined to microwave-assisted extraction (IL-MAE) was successfully applied for metabolites extraction from Pseudevernia furfuracea. MATERIALS AND METHODS: Three imidazolium and pyridinium-based ionic liquids (ILs): 1,3-dimethylimidazolium methylsulphate [C(1) C(1) Im][MeSO(4) ], 1-ethyl-3-methylimidazolium ethylsulphate [C(2) C(1) Im][EtSO(4) ], and N-ethylpyridinium ethylsulphate [C(2) Py][EtSO(4) ] were assessed for this process. The efficiency of the extraction method was evaluated using thin-layer chromatography (TLC) coupled to a Camag® spectrophotodensitometer and using high-performance liquid chromatography (HPLC) analysis. RESULTS: ILs under MAE showed extraction time efficiency (15 min vs. 24 h for conventional heating) and high selectivity in extracting the targeted metabolites: atranorin (AT), methyl-β-orcinol carboxylate (MOC), fumarprotocetraric acid (Fum. Ac.), and physodic acid (Phys. Ac.) despite the increased degradation of AT under MAE. We showed a tunable selectivity of ILs towards extracting metabolites by changing anion or cation due to the modification of the interaction between the IL and the metabolites. While [C(2) Py][EtSO(4) ] was the most efficient IL and could extract all the targeted metabolites, [C(2) C(1) Im][EtSO(4) ] was the most selective. It fully extracted AT and partially Fum. Ac. Moreover, the lichen prepared by mixing procedure provided AT and Fum. Ac. more than the milled one. A 100 times scale-up extraction was successfully performed on mixed samples with full IL recycling after back extraction. CONCLUSION: IL-MAE is reliable for lichen metabolites extraction. The method is reproducible, scalable, with possible IL recycling, opening the door for potential industrial applications