Diversity of grapevine yellows in Germany

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Diversity among mycoplasma-like organisms inducing grapevine yellows in France

As antibodies and molecular probes which were previously obtained for diagnosis of grapevine flavescence doree (FD; a yellows disease induced by a MLO), showed to be highly specific, a survey of grapevine samples collected in different viticultural areas in France was undertaken, using a PCR method with primers allowing amplification of a part of the 16S rRNA gene of most MLOs, and restriction analyses of the amplified products (AHRENS and SEEMÜLLER 1992). The presence of MLO was established in all the different grapevine samples, and their diversity was demonstrated. The typcial pattern yielded by FD sensu stricto-MLO was found in samples from southern vineyards, including a symptomless rootstock. Two different patterns were found in samples affected by bois noir disease of northern French vineyards, one of these patterns being previously undescribed. The present survey was non exhaustive and should be followed in the frame of a large collaboration between viticultural countries. It showed the diversity in causal agents of diseases which converge in symptomatology, and emphasizes on the need of specific diagnosis tools, for identification of each of the vector species, for epidemiological studies, and availability of planting material

A comparison of the phytoplasma associated with Australian grapevine yellows to other phytoplasmas in grapevine

The phytoplasma associated with Australian grapevine yellows (AGY) was compared to other phytoplasma diseases of grapevine using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Comparison of eight different Australian isolates suggests that only one type of phytoplasma is associated with this disease. Based on RFLP analysis of the 16S rRNA gene, it was shown that AGY is different from the tomato big bud and sweet potato little leaf phytoplasma strains which are widespread in Australia and that it represents the only other phytoplasma strain recorded in Australia to date. Restriction profiles of grapevine phytoplasmas using Mse I suggest that AGY is unique but most closely resembles those phytoplasmas associated with grapevine diseases in the stolbur group. Sequence analysis of the 16S rRNA gene and adjacent spacer region supports this association. The uniqueness of AGY was confirmed by PCR assays using non-ribosomal primers; the primer pair STOL11f/r2 specific for stolbur phytoplasmas did not result in amplification products in grapevines affected with AGY; the primer pair fMLOl/rMLOl which amplifies a region of the tuf gene from phytoplasmas in the aster yellows cluster, amplified AGY DNA confirming its association within this phylogenetic group. RFLP analysis of the tufPCR product again highlighted a distinction between AGY and other stolbur phytoplasmas occurring in grapevine. The only other phytoplasma in Australia which is in the stolbur group is associated with dieback in papaya, and it has the same RFLP profile of the tuf PCR product as AGY

Design, synthesis and biological evaluation of a new series of carvedilol derivatives that protect sensory hair cells from aminoglycoside-induced damage by blocking the mechanoelectrical transducer channel

Aminoglycosides (AGs) are broad-spectrum antibiotics used for the treatment of serious bacterial infections but have use-limiting side effects including irreversible hearing loss. Here, we assessed the otoprotective profile of carvedilol in mouse cochlear cultures and in vivo zebrafish assays and investigated its mechanism of protection which, we found, may be mediated by a block of the hair cell’s mechanoelectrical transducer (MET) channel, the major entry route for the AGs. To understand the full otoprotective potential of carvedilol, a series of 18 analogues were prepared and evaluated for their effect against AG-induced damage as well as their affinity for the MET channel. One derivative was found to confer greater protection than carvedilol itself in cochlear cultures and also to bind more tightly to the MET channel. At higher concentrations, both carvedilol and this derivative were toxic in cochlear cultures but not in zebrafish, suggesting a good therapeutic window under in vivo conditions

Whole genome sequencing of drug resistant Mycobacterium tuberculosis isolates from a high burden tuberculosis region of North West Pakistan

Tuberculosis (TB), caused by Mycobacterium tuberculosis bacteria, is a leading infectious cause of mortality worldwide, including in Pakistan. Drug resistant M. tuberculosis is an emerging threat for TB control, making it important to detect the underlying genetic mutations, and thereby inform treatment decision making and prevent transmission. Whole genome sequencing has emerged as the new diagnostic to reliably predict drug resistance within a clinically relevant time frame, and its deployment will have the greatest impact on TB control in highly endemic regions. To evaluate the mutations leading to drug resistance and to assess for evidence of the transmission of resistant strains, 81 M. tuberculosis samples from Khyber Pakhtunkhwa province (North West Pakistan) were subjected to whole genome sequencing and standard drug susceptibility testing for eleven anti-TB drugs. We found the majority of M. tuberculosis isolates were the CAS/Delhi strain-type (lineage 3; n = 57; 70.4%) and multi-drug resistant (MDR; n = 62; 76.5%). The most frequent resistance mutations were observed in the katG and rpoB genes, conferring resistance to isoniazid and rifampicin respectively. Mutations were also observed in genes conferring resistance to other first and second-line drugs, including in pncA (pyrazinamide), embB (ethambutol), gyrA (fluoroquinolones), rrs (aminoglycosides), rpsL, rrs and giB (streptomycin) loci. Whilst the majority of mutations have been reported in global datasets, we describe unreported putative resistance markers in katG, ethA (ethionamide), gyrA and gyrB (fluoroquinolones), and pncA. Analysis of the mutations revealed that acquisition of rifampicin resistance often preceded isoniazid in our isolates. We also observed a high proportion (17.6%) of pre-MDR isolates with fluoroquinolone resistance markers, potentially due to unregulated anti-TB drug use. Our isolates were compared to previously sequenced strains from Pakistan in a combined phylogenetic tree analysis. The presence of lineage 2 was only observed in our isolates. Using a cut-off of less than ten genome-wide mutation differences between isolates, a transmission analysis revealed 18 M. tuberculosis isolates clustering within eight networks, thereby providing evidence of drug-resistant TB transmission in the Khyber Pakhtunkhwa province. Overall, we have demonstrated that drug-resistant TB isolates are circulating and transmitted in North West Pakistan. Further, we have shown the usefulness of whole genome sequencing as a diagnostic tool for characterizing M. tuberculosis isolates, which will assist future epidemiological studies and disease control activities in Pakistan

Homozygosity for a missense mutation in the 67 kDa isoform of glutamate decarboxylase in a family with autosomal recessive spastic cerebral palsy: parallels with Stiff-Person Syndrome and other movement disorders

Background Cerebral palsy (CP) is an heterogeneous group of neurological disorders of movement and/or posture, with an estimated incidence of 1 in 1000 live births. Non-progressive forms of symmetrical, spastic CP have been identified, which show a Mendelian autosomal recessive pattern of inheritance. We recently described the mapping of a recessive spastic CP locus to a 5 cM chromosomal region located at 2q24-31.1, in rare consanguineous families. Methods Here we present data that refine this locus to a 0.5 cM region, flanked by the microsatellite markers D2S2345 and D2S326. The minimal region contains the candidate gene GAD1, which encodes a glutamate decarboxylase isoform (GAD67), involved in conversion of the amino acid and excitatory neurotransmitter glutamate to the inhibitory neurotransmitter γ-aminobutyric acid (GABA). Results A novel amino acid mis-sense mutation in GAD67 was detected, which segregated with CP in affected individuals. Conclusions This result is interesting because auto-antibodies to GAD67 and the more widely studied GAD65 homologue encoded by the GAD2 gene, are described in patients with Stiff-Person Syndrome (SPS), epilepsy, cerebellar ataxia and Batten disease. Further investigation seems merited of the possibility that variation in the GAD1 sequence, potentially affecting glutamate/GABA ratios, may underlie this form of spastic CP, given the presence of anti-GAD antibodies in SPS and the recognised excitotoxicity of glutamate in various contexts