Bildung Glucosinolat-abgeleiteter Nitrile in Wurzeln von Arabidopsis thaliana: Analytik von Indol-Glucosinolat-Abbauprodukten und Effekte auf die mikrobielle Gemeinschaft der Rhizosphäre

Arabidopsis thaliana is a glucosinolate containing plant, using the glucosinolate-myrosinase system as a chemical defense against insects and microbial pathogens, mainly by the effects of glucosinolate-derived isothiocyanates. Nitrile-specifier proteins (NSPs) act upon breakdown of glucosinolates and lead to the formation of simple nitriles at the expense of isothiocyanates and derived products. Roots of A. thaliana Col-0 express three NSPs: NSP1/-3/-4. The fate of indole glucosinolates, which are predominant in roots, upon breakdown is less well understood as methods for the detection and quantitation of breakdown products such as nitriles and carbinols are lacking. Moreover, the biological relevance of NSP abundance in roots is unknown. Effects of a lacking ability to form nitriles on soil microbes is conceivable. The following results were obtained and highlight the importance of especially aliphatic glucosinolate biosynthesis, but also of the ability to generate nitriles upon glucosinolate breakdown for the assembly of the bacterial/archaeal communities in the rhizosphere of A. thaliana: Derivatisation conditions were established which allow for a GC-MS based quantitation method for indolic carbinols and nitriles in plant homogenates. The quantitation method was successfully applied to homogenates of multiple A. thaliana lines, demonstrating an impact of NSPs on glucosinolate breakdown product profiles. NSP1 was identified as the main contributor to nitrile formation from indole glucosinolates while NSP3 did not contribute. The newly generated line nsp134 with non-functional alleles of NSP1, NSP3 and NSP4 was cha-racterised phytochemically. This demonstrated a lack of nitrile formation in homogenates of roots and rosettes. Mutant lines with defects in glucosinolate biosynthesis (cyp79b2/b3, myb28/29, qKO) or nitrile formation (nsp1-1, nsp3-2, nsp134) were grown for isolation of total community-DNA from the rhizosphere in comparison to Col-0. The bact./arch. community composition of the rhizosphere was analysed by DGGE and 16S rRNA gene amplicon sequencing. DGGE community fingerprinting targeting the bact./ arch. microbiota identified differences between all genotypes and Col-0, and a rhizosphere effect. Reduced alpha-diversity indices were observed in the bact./ arch. community of the myb28/29 mutant in comparison to Col-0. Effects on the beta-diversity were demonstrated for the rhizosphere community of all genotypes in comparison to Col-0. Alterations of the core microbiota were identified on the genus rather than the phylum level, with an influence on several taxa throughout all tested genotypes. The myb28/29, followed by the qKO genotype showed the strongest overall effects regarding beta-diversity and community composition, but NSP mutants also showed significant effects. For some genera, the effects of NSP deficiency were strikingly distinct from those of impaired glucosinolate biosynthesis, as expressed by opposing relative. This emphasised the differential reactions of microbial taxa in the rhizosphere to the absence or presence of aliphatic and indole glucosinolate-derived breakdown products.Als Glucosinolat-enthaltende Pflanze verwendet Arabidopsis thaliana das Glucosinolat-Myrosinase-System zur chemischen Verteidigung gegen Insekten und mikrobielle Pathogene, v.a. wegen der Effekte der Glucosinolat-abgeleiteten Isothiocyanate. Nitril-spezifizierende Proteine (NSPs) wirken auf den Abbau von Glucosinolaten ein und führen zur Bildung von Nitrilen auf Kosten von Isothiocyanaten und abgeleiteten Produkten. Wurzeln von A. thaliana Col-0 exprimieren drei NSPs: NSP1, NSP3 und NSP4. Das Schicksal der vorherrschend in den Wurzeln vorkommenden Indol-Glucosinolate beim Abbau ist weniger gut aufgeklärt, da Detektions- und Quantifizierungsmethoden für Carbinole und Nitrile fehlen. Außerdem ist die biologische Relevanz des NSP-Vorkommens in Wurzeln unbekannt. Effekte einer fehlenden Fähigkeit zur Nitril-Bildung auf Boden-Mikroorganismen sind denkbar. Folgende Ergebnisse wurden erzielt, die die Bedeutung von v.a. der Biosynthese aliphatischer Glucosinolate, aber auch von der Fähigkeit, Nitrile während des Glucosinolat-Abbaus herzustellen, für die Zusammenstellung der Bakterien-/Archaeen-Gemeinschaft in der Rhizosphäre von A. thaliana herausstellen: GC-MS-geeignete Derivatisierungsbedingungen für die Quantifizierung von indolischen Carbinolen und Nitrilen in Pflanzenhomogenaten wurden etabliert. Die Methode wurde erfolgreich auf Homogenate verschiedener A. thaliana-Linien angewandt. Hierbei konnte ein Einfluss von NSPs auf die Profile von Glucosinolat-Abbauprodukten gezeigt werden. NSP1 wurde als Haupt-Beiträger zur Nitrilbildung aus Indol-Glucosinolaten in Homogenaten identifiziert, während NSP3 nicht beitrug. Die neu hergestellte Linie nsp134 mit nicht-funktionellen Allelen von NSP1/-3/-4, wurde phytochemisch charakterisiert. Hierbei wurde ein Fehlen der Nitrilbildung aus Glucosinolaten in Wurzel- und Rosettenhomogenaten gezeigt. Neben Col-0 wurden verschiedene Mutanten mit entsprechenden Defekten in der Glucosinolat-Biosynthese (cyp79b2/b3, myb28/29, qKO) oder Nitrilbildung (nsp1-1, nsp3-2, nsp134) angezogen. Die total community-DNA wurde isoliert und per DGGE und 16S rRNA gene amplicon sequencing wurden Analysen der Bakt.-/Arch.-Gemeinschaft in der Rhizosphäre durchgeführt. DGGE-Fingerprinting der Bakt.-/Arch.-Gemeinschaft identifizierte Unterschiede zwischen allen Genotypen und Col-0, sowie einen Rhizosphären-Effekt. Reduzierte Alpha-Diversitäts-Indizes im Vergleich zu Col-0 wurden für die Bakt.-/Arch.-Gemeinschaft der myb28/29-Mutante beobachtet. Effekte auf die Beta-Diversität waren für alle Genotypen im Vergleich zu Col-0 nachweisbar. Veränderungen des Kernmikrobioms wurden stärker auf Genus- als auf Phylum-Ebene identifiziert. Der myb28/29-Genotyp, gefolgt qKO, hatte den stärksten Einfluss auf die Beta-Diversität und die Zusammensetzung der Rhizosphären-Gemeinschaft, aber auch für die NSP-Mutanten wurden signifikante Effekte beobachtet. Effekte auf ausgewählte Genera zeigten deutliche Unterschiede in Bezug auf NSP-Mangel verglichen mit beeinträchtigter Glucosinolat-Biosynthese, ausgedrückt durch gegenläufige relative Abundanzen der Taxa. Dies betonte die differentiellen Reaktionen der mikrobiellen Taxa auf die Ab- bzw. Anwesenheit von Abbauprodukten von aliphatischen und Indol-Glucosinolaten

Protocol for piloting a phone-based web survey to elicit barriers to accessing triage camps within community-based, Peek-powered eye screening programmes

Pilot study summaryTitle Piloting a phone-based web survey to elicit barriers to accessing triage camps within community-based, Peek-powered eye screening programmes Design Pilot test of an online survey sent via SMS to 1,600 parents/guardians of children who did not attend eye clinics having been found to have an eye need at school screening. We will perform the same pilot twice; once in Botswana and once in Nepal Aims To quantify the response rate among 16 different subgroups of recipients according to gender, location, wealth and assets. Note that we are not concerned with the responses at this pilot phase – only the suitability of the medium. Population Parents/guardians of children who did not attend screening within Botswana’s Peek-powered national school-based ‘Pono Yame’ programme, and participants in Nepal’s Peek-powered community screening programme Intervention A four-question online survey exploring barriers to attendance. The hyperlink will be sent via SMS. Non-responders will receive a single follow-up reminder 7 days later. Outcome measure Cumulative survey completion rates over the 31 days that follow the original SMS invitation. Duration All survey invitations will be sent on the same day. As such, the pilot will last 31 days

Protocol for an automated, pragmatic, embedded, adaptive randomised controlled trial: behavioural economics-informed mobile phone-based reminder messages to improve clinic attendance in a Botswanan school-based vision screening programme.

BACKGROUND: Clinic non-attendance rates are high across the African continent. Emerging evidence suggests that phone-based reminder messages could make a small but important contribution to reducing non-attendance. We will use behavioural economics principles to develop an SMS and voice reminder message to improve attendance rates in a school-based eye screening programme in Botswana. METHODS: We will test a new theory-informed SMS and voice reminder message in a national school-based eye screening programme in Botswana. The control will be the standard SMS message used to remind parents/guardians to bring their child for ophthalmic assessment. All messages will be sent twice. The primary outcome is attendance for ophthalmic assessment. We will use an automated adaptive approach, starting with a 1:1 allocation ratio. DISCUSSION: As far as we are aware, only one other study has used behavioural economics to inform the development of reminder messages to be deployed in an African healthcare setting. Our study will use an adaptive trial design, embedded in a national screening programme. Our approach can be used to trial other forms of reminder message in the future. TRIAL REGISTRATION: ISRCTN 96528723 . Registered on 5 January 2022

Structure and origin of the J Anomaly Ridge, western North Atlantic Ocean

Author Posting. © American Geophysical Union, 1982. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 87, no. B11 (1982): 9389–9407, doi:10.1029/JB087iB11p09389.The J Anomaly Ridge is a structural ridge or step in oceanic basement that extends southwest from the eastern end of the Grand Banks. It lies beneath the J magnetic anomaly at the young end (M-4 to M-0) of the M series magnetic anomalies. Its structural counterpart beneath the J anomaly in the eastern Atlantic is the Madeira-Tore Rise, but this feature has been overprinted by post-middle Cretaceous deformation and volcanism. In order to study the origin and evolution of the J Anomaly Ridge-Madeira-Tore Rise system, we obtained seismic refraction and multichannel reflection profiles across the J Anomaly Ridge near 39°N latitude. The western ridge flank consists of a series of crustal blocks downdropped along west-dipping normal faults, but the eastern slope to younger crust is gentle and relatively unfaulted. The western flank also is subparallel to seafloor isochrons, becoming younger to the south. Anomalously smooth basement caps the ridge crest, and it locally exhibits internal, eastward-dipping reflectors similar in configuration to those within subaerially emplaced basalt flows on Iceland. When isostatically corrected for sediment load, the northern part of the J Anomaly Ridge has basement depths about 1400 m shallower than in our study area, and deep sea drilling has shown that the northern ridge was subaerially exposed during the middle Cretaceous. We suggest that most of the system originated under subaerial conditions at the time of late-stage rifting between the adjacent Grand Banks and Iberia. The excess magma required to form the ridge may have been vented from a mantle plume beneath the Grand Banks-Iberia rift zone and channelled southward beneath the rift axis of the abutting Mid-Atlantic Ridge. Resulting edifice-building volcanism constructed the ridge system between anomalies M-4 and M-0, moving southward along the ridge axis at about 50 mm/yr. About M-0 time, when true drift began between Iberia and the Grand Banks, this southward venting rapidly declined. The results were rapid return of the spreading axis to normal elevations, division of the ridge system into the separate J Anomaly Ridge and Madeira-Tore Rise, and unusually fast subsidence of at least parts of these ridges to depths that presently are near normal. This proposed origin and evolutionary sequence for the J Anomaly Ridge-Madeira-Tore Rise system closely matches events of uplift and unconformity development on the adjacent Grand Banks.This research was supported by the Office of Naval Research, contracts N00014-75-C-0210 and N00014-80-C-0098 to Lamont-Doherty Geological Observatory and contract N00014-79-C-0071 to Woods Hole Oceanographic Institution

A seismic refraction line across Norfolk

AbstractA simple seismic refraction line some 115 km long has been made across Norfolk to provide constraints on the depth to the ‘igneous/metamorphic’ basement. Shots were fired in the Wash and off the coast near Lowestoft and attempts were made to record at approximately 2 km intervals along the line. Recording quality was only fair, resulting in incomplete coverage of the line, and this restricts the quality of interpretation. The results show a refractor of about 6.05 km s−1 revealed over the whole line with no first-arrival evidence of the 4.5–5.5 km s−1 velocity expected from Palaeozoic sediments. Using estimated velocities of 2.4 km s−1 for the post-Palaeozoic succession, 4.5–5.5 km s−1 for the Palaeozoic succession and an estimated sub-crop position of the basement on the sub-Mesozoic floor, models are produced which suggest that the Palaeozoic sediments are no more than 600–1500 m thick at the eastern end of the line, depending on the Palaeozoic velocity assumed.</jats:p

Seismic velocities of granulites from the Seiland Petrographic Province (N. Norway): Implications for Scandinavian lower continental crust

Compressional and shear wave velocities have been measured in the laboratory at up to 1.0 GPa effective pressure on a suite of granulite facies rocks from the Seiland Petrographic Province. The suite may be of Precambrian age and the measurements were made to test a proposal that the suite represents lower continental crust. Compressional wave velocities at 0.4 GPa effective pressure range from 6.41–6.97 km s-1 with a mean of 6.71 km s-1 . Measurements of the parameter (∂V/∂Tp) suggest a value of a –0.8 x 10-3 km s-1 ºC-1 , and the temperature corrected mean velocity of about 6.5 km s-1 at 20 km depth is comparable to that found in parts of the lower crust in Scandinavia. The mean Poisson's ratio of 0.29 at 0.4 GPa is slightly higher than that found (0.276), but could be reduced if heterogeneity in the suite and the effect of higher pressures are taken into account. The occurrence of lower continental crust as a thrust slice in the Province is consistent with current ideas on the geological evolution of this area. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ARK: https://n2t.net/ark:/88439/y080958 Permalink: https://geophysicsjournal.com/article/260 &nbsp