957 research outputs found
Phytoplasma: Ecology and genomic diversity
No full textThe recent development of molecular-based probes such as mono- and polyclonal antibodies, cloned phytoplasma DNA fragments, and phytoplasma-specific primers for polymerase chain reaction (PCR) has allowed for advances in detection and identification of uncultured phytoplasmas (formerly called mycoplasma-like organisms). Comprehensive phylogenetic studies based on analysis of 16S ribosomal RNA (rRNA) or both 16S rRNA and ribosomal protein gene operon sequences established the phylogenetic position of phytoplasmas as members of the class Mollicutes, and the revealed phylogenetic interrelationships among phytoplasmas formed a basis for their classification. Based on restriction fragment length polymorphism (RFLP) analysis of PCR-amplified 16S rRNA gene sequences, phytoplasmas are currently classified into 14 groups and 38 subgroups that are consistent with groups delineated based on phylogenetic analysis using parsimony of 16S rRNA gene sequences. In the past decades, numerous phytoplasma strains associated with plants and insect vectors have been identified using molecular-based tools. Genomic diversity of phytoplasma groups appears to be correlated with their sharing common insect vectors, host plants, or both in nature. The level of exchange of genetic information among phytoplasma strains in a given group is determined by three-way, vector-phytoplasma-plant interactions. A putative mechanism for the creation of new ecological niches and the evolution of new ecospecies is proposed
‘Candidatus Phytoplasma asteris’, a novel phytoplasma taxon associated with aster yellows and related diseases.
No full textAster yellows (AY) group (16SrI) phytoplasmas are associated with over 100 economically
important diseases worldwide and represent the most diverse and widespread phytoplasma
group. Strains that belong to the AY group form a phylogenetically discrete subclade within the
phytoplasma clade and are related most closely to the stolbur phytoplasma subclade, based on
analysis of 16S rRNA gene sequences. AY subclade strains are related more closely to their
culturable relatives, Acholeplasma spp., than any other phytoplasmas known. Within the AY
subclade, six distinct phylogenetic lineages were revealed. Congruent phylogenies obtained by
analyses of tuf gene and ribosomal protein (rp) operon gene sequences further resolved the
diversity among AY group phytoplasmas. Distinct phylogenetic lineages were identified by RFLP
analysis of 16S rRNA, tuf or rp gene sequences. Ten subgroups were differentiated, based on
analysis of rp gene sequences. It is proposed that AY group phytoplasmas represent at least one
novel taxon. Strain OAY, which is a member of subgroups 16SrI-B, rpI-B and tufI-B and is
associated with evening primrose (Oenothera hookeri ) virescence in Michigan, USA, was selected
as the reference strain for the novel taxon ‘Candidatus Phytoplasma asteris’. A comprehensive
database of diverse AY phytoplasma strains and their geographical distribution is presented
Molecular identification of a new phytoplasma associated with alfalfa witches'-broom in Oman
No full textAlfalfa (Medicago sativa) plants showing witches'-broom symptoms typical of phytoplasmas were observed from Al-Batinah, Al-Sharqiya, Al-Bureimi, and interior regions of the Sultanate of Oman. Phytoplasmas were detected from all symptomatic samples by the specific amplification of their 16S-23S rRNA gene. Polymerase chain reaction (PCR), utilizing phytoplasma-specific universal primer pairs, consistently amplified a product of expected lengths when DNA extract from symptomatic samples was used as template. Asymptomatic plant samples and the negative control yielded no amplification. Restriction fragment length polymorphism profiles of PCR-amplified 16S-23S rDNA of alfalfa using the P1/P7 primer pair identified phytoplasmas belonging to peanut witches'-broom group (16SrII or faba bean phyllody). Restriction enzyme profiles showed that the phytoplasmas detected in all 300 samples belonged to the same ribosomal group. Extensive comparative analyses on P1/P7 amplimers of 20 phytoplasmas with Tru9I, Tsp509I, HpaII, TaqI, and RsaI clearly indicated that this phytoplasma is different from all the other phytoplasmas employed belonging to subgroup 16SrII, except tomato big bud phytoplasma from Australia, and could be therefore classified in subgroup 16SrII-D. The alfalfa witches'-broom (AlfWB) phytoplasma P1/P7 PCR product was sequenced directly after cloning and yielded a 1,690-bp product. The homology search showed 99% similarity (1,667 of 1,690 base identity) with papaya yellow crinkle (PapayaYC) phytoplasma from New Zealand. A phylogenetic tree based on 16S plus spacer regions sequences of 35 phytoplasmas, mainly from the Southern Hemisphere, showed that AlfWB is a new phytoplasma species, with closest relationships to PapayaYC phytoplasmas from New Zealand and Chinese pigeon pea witches'-broom phytoplasmas from Taiwan but distinguishable from them considering the different associated plant hosts and the extreme geographical isolation
Phylogeny and classification of the Sciaroidea (Diptera: Bibionomorpha): Where do we stand after Amorim & Rindal (2007)?
Get PDFEine Publikation zur Phylogenie der Sciaroidea von D. Amorim und E. Rindal aus dem Jahr 2007 wird besprochen. Die phylogenetische Hypothese, die die Autoren aus ihrer quantitativen morphologischen Analyse abgeleitet haben, wird von ihnen benutzt, um eine Neuklassifikation der Sciaroidea vorzuschlagen. Diese unterscheidet sich grundlegend von bisherigen Klassifikationen. In der vorliegenden Besprechung wird an Beispielen aufgezeigt, dass die von Amorim und Rindal benutzte Merkmalsmatrix auf verheerende Weise fehlerhaft ist, sowohl was die eingesetzten Taxa als auch die verwendeten Merkmale betrifft. Im Ergebnis muss festgestellt werden, dass diese Verwandtschaftsanalyse nicht wiederholbar und die daraus resultierende Verwandtschaftshypothese weder nachprüfbar noch widerlegbar ist. Deshalb wird nahegelegt, die in Rede stehende Publikation nicht zur Begründung etwaiger Änderungen an der bestehenden Sciaroidea-Klassifikation heranzuziehen.StichwörterDiptera, Sciaroidea, phylogeny, family classification, review.A paper on the phylogeny of the Sciaroidea by D. Amorim and E. Rindal from 2007 is reviewed. The phylogenetic hypothesis derived from morphological quantitative analysis is used by these authors to propose a new classification of the Sciaroidea which differs significantly from previous classifications. In the present review it is shown by way of examples that the data matrix used by Amorim and Rindal is fatally flawed in terms of both the employed taxa and characters. As a result, the analysis is not repeatable and the hypothesis resulting from it is neither testable nor rebuttable. It is suggested that the paper in question should not be used as a basis for changes in the traditional classification of the Sciaroidea.KeywordsDiptera, Sciaroidea, phylogeny, family classification, review
Molecular identification of 16SrII-D subgroup phytoplasmas associated with chickpea and faba bean in Sudan
Get PDF[EN] In January 2011, symptomatic chickpea and faba bean plants were observed in fields located in the Gezira state (Sudan). Faba bean plants showed yellowing and stunting, whereas chickpea plants presented yellowing, reddening and little leaves. The disease etiology was investigated using nested polymerase chain reaction (PCR) with phytoplasma-specific primers which amplify a fragment of the 16S rRNA gene. Sequencing and restriction fragment length polymorphism (RFLP) analyses revealed that the tested phytoplasmas belonged to the group 16SrII. Phylogenetic analyses of the 16S rRNA gene of the obtained sequences indicated that the chickpea and faba bean phytoplasmas from Sudan were more closely related to the phytoplasmas subgroup 16SrII-D. To our knowledge, this is the first report of phytoplasmas from the group 16SrII-D infecting chickpea in Sudan, and faba bean worldwide.Alfaro Fernández, AO.; Mai Abdala, A.; Abdelraheem, FM.; Saeed, EAE.; Font San Ambrosio, MI. (2012). Molecular identification of 16SrII-D subgroup phytoplasmas associated with chickpea and faba bean in Sudan. European Journal of Plant Pathology. 133(4):791-795. https://doi.org/10.1007/s10658-012-9975-7S7917951334Akthar, K. P., Shah, T. M., Atta, B. M., Dickinson, M., Jamil, F. F., Haq, M. A., et al. (2008). Natural occurrence of phytoplasma associated with chickpea phyllody disease in Pakistan—a new record. Plant Pathology, 57, 771.Bertaccini, A., & Duduk, B. (2009). Phytoplasma and phytoplasma diseases: a review of recent research. Phytopathologia Mediterranea, 48, 355–378.Deng, S., & Hiruki, C. (1991). Genetic relatedness between two non-culturable micoplasma-like organisms revealed by nucleic acid hybridization and polymerase chain reaction. Phytopathology, 81, 1475–1479.Green, M. J., & Thompson, D. A. (1999). Easy and efficient DNA extraction from woody plants for the detection of phytoplasmas by polymerase chain reaction. Plant Disease, 83, 482–485.Gundersen, D. E., & Lee, I. M. (1996). Ultrasensitive detection of phytoplasmas by nested-PCR assays using two universal primer pairs. Phytopathologia Mediterranea, 35, 144–151.IRPCM. (2004). “Candidatus Phytoplasma”, a taxon for the wall-less, non-helical prokaryotes that colonize plant phloem and insects. International Journal of Systematic and Evolutionary Microbiology, 54, 1243–1255.Jones, P., & Cockbain, A. J. (1984). Association of a mycoplasma-like organism with broad bean phyllody in the Sudan. Plant Pathology, 33, 599–602.Khan, A. J., Botti, S., Al-Subhi, A. M., Gundersen-Rindal, D. E., & Bertaccini, A. F. (2002). Molecular identification of a new phytoplasma associated with Alfalfa witches’—broom in Oman. Phytopathology, 92, 1038–1047.Lee, I.-M., Gundersen-Rindal, D. E., Davis, R. E., & Bartoszyk, I. M. (1998). Revised classification scheme of phytoplasmas based on RFLP analyses of 16S rRNA and ribosomal protein genes sequences. International Journal of Systematic Bacteriology, 48, 1153–1169.Lee, I. M., Davis, R. E., & Gundersen-Rindal, D. E. (2000). Phytoplasma: phytopathogenic mollicutes. Annual Review of Microbiology, 5, 221–255.Schneider, B., Seemüller, E., Smart, C. D., & Kirkpatrick, B. C. (1995). Phylogenetic classification of plant pathogenic mycoplasma-like organisms or phytoplasmas. In S. Razin & J. G. Tully (Eds.), Molecular and diagnostic procedures in Micoplasmology, vol. 1 (pp. 369–380). San Diego: Academic Press.Schneider, B., Gibb, K. S., & Seemüller, E. (1997). Sequence and RFLP analysis of the elongation factor Tu gene used in differentiation and classification of phytoplasmas. Microbiology, 143, 3381–3389.Tamura, K., Peterson, D., Peterson, N., Stecher, G., Nei, M., & Kumar, S. (2011). MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods. Molecular Biology and Evolution, 28, 2731–2739.White, D. T., Blackall, L. L., Scott, T., & Walsh, K. B. (1998). Phylogenetic positions of phytoplasmas associated with dieback, yellow crinkle and mosaic diseases of papaya, and their proposed inclusion in “Candidatus Phytoplasma australiense” and a new taxon “Candidatus Phytoplasma australasia”. International Journal of Systematic Bacteriology, 48, 941–951
Intrathecal levels of vitamin D and IgG in multiple sclerosis
No full textBackground- Intrathecal synthesis of IgG is a hallmark of multiple sclerosis (MS). Vitamin D may modulate B-cell function and dampen the synthesis of IgG. Objective- To investigate the relation between vitamin D levels in cerebrospinal fluid and serum and intrathecal synthesis of IgG. Methods- 25-hydroxyvitamin D (25(OH)D) and IgG were assessed in cerebrospinal fluid and serum in 40 patients with MS. Results- There was no significant correlation between the IgG index and 25(OH)D levels in cerebrospinal fluid or serum. The levels of 25(OH)D in cerebrospinal fluid and serum did not differ between patients with and without intrathecal synthesis of IgG. There was a non-significant trend towards a positive correlation between the concentrations of 25(OH)D and IgG in the cerebrospinal fluid, but not in serum. Conclusion- Physiological variation in vitamin D does not exert a major impact on intrathecal synthesis of IgG in MS. © 2011 John Wiley & Sons A/S
Characterization and transcriptional analysis of protein tyrosine phosphatase genes and an ankyrin repeat gene of the parasitoid Glyptapanteles indiensis polydnavirus in the parasitized host
No full textOhakunea chilensis Freeman
No full textOhakunea chilensis Freeman (Figs. 32–37) The species has been redescribed recently by Jaschhof & Hippa (2003), and no additions are necessary. We illustrate here some aspects of the species important for character analysis. Material examined. 1 ♂, S. CHILE, Llanquihue prov., Casa Pangue, F. & M. Edwards, 4–10.xii.1926, B.M. 1927, Paul Freeman det.; 2 ♂♂, CHILE, Dalcahue, I. Chiloé, i.1962, L. E. Peña col., Det. D. S. Amorim 1983; 1 ♀, same data, but iv.1968, L. E. Peña col., Det. D. S. Amorim 1983 (MZSP).Published as part of DE SOUZA AMORIM, DALTON & RINDAL, EIRIK, 2007, Phylogeny of the Mycetophiliformia, with proposal of the subfamilies Heterotrichinae, Ohakuneinae, and Chiletrichinae for the Rangomaramidae (Diptera, Bibionomorpha), pp. 1-92 in Zootaxa 1535 (1) on page 18, DOI: 10.11646/zootaxa.1535.1.1, http://zenodo.org/record/508851
Norway 1943
No full textRelief shown by contours and spot heights.
Title varies: Deutsche Heereskarte. --Truppenkart. --Bildplankarte.
The sheets entitled Bildplankarte are photo maps.
Maps are based on Norwegian originals.
On most sheets: Als Schiesskart geeignet, Nur für den Dienstgebrauch.
Some sheets have military grid.C 26 O Molde (Nordteil) -- C 26 O Molde (Südteil) -- C 26 W Haram (Südteil) -- C 27 O Örskog (Nordteil) -- C 27 W Borgund (Nordteil) -- D 25 W Bremsnes (Südteil) -- D 26 O Nesset (Südteil) -- D 26 W Bolsöy (Nordteil) -- D 26 W Bolsöy (Südteil) -- D 27 O Romsdalen (Nordteil) -- D 27 W Voll (Nordteil) -- E 25 O Rindal (Südteil) -- E 25 W Halsa (Südteil) -- E 26 O Trollheimen (Nordteil) -- E 26 O Trollheimen (Südteil) -- E 26 W Stangvik (Südteil) -- E 27 O Romfo (Nordteil) -- E 27 W Aura (Nordteil).Color;1:50,00
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