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1.
Łukasz Wejnerowski Ewa Poniecka Jakub Buda Piotr Klimaszyk Agnieszka Piasecka Marcin Krzysztof Dziuba Gianmarco Mugnai Nozomu Takeuchi Krzysztof Zawierucha 《Journal of phycology》2023,59(5):939-949
Cryoconite, the dark sediment on the surface of glaciers, often aggregates into oval or irregular granules serving as biogeochemical factories. They reduce a glacier's albedo, act as biodiversity hotspots by supporting aerobic and anaerobic microbial communities, constitute one of the organic matter (OM) sources on glaciers, and are a feeder for micrometazoans. Although cryoconite granules have multiple roles on glaciers, their formation is poorly understood. Cyanobacteria are ubiquitous and abundant engineers of cryoconite hole ecosystems. This study tested whether cyanobacteria may be responsible for cryoconite granulation as a sole biotic element. Incubation of Greenlandic, Svalbard, and Scandinavian cyanobacteria in different nutrient availabilities and substrata for growth (distilled water alone and water with quartz powder, furnaced cryoconite without OM, or powdered rocks from glacial catchment) revealed that cyanobacteria bind mineral particles into granules. The structures formed in the experiment resembled those commonly observed in natural cryoconite holes: they contained numerous cyanobacterial filaments protruding from aggregated mineral particles. Moreover, all examined strains were confirmed to produce extracellular polymeric substances (EPS), which suggests that cryoconite granulation is most likely due to EPS secretion by gliding cyanobacteria. In the presence of water as the only substrate for growth, cyanobacteria formed mostly carpet-like mats. Our data empirically prove that EPS-producing oscillatorialean cyanobacteria isolated from the diverse community of cryoconite microorganisms can form granules from mineral substrate and that the presence of the mineral substrate increases the probability of the formation of these important and complex biogeochemical microstructures on glaciers. 相似文献
2.
The organization of DNA sequences in the mouse genome 总被引:1,自引:1,他引:0
Analysis of the organization of nucleotide sequences in mouse genome is carried out on total DNA at different fragment size, reannealed to intermediate value of Cot, by Ag+-Cs2SO4 density gradient centrifugation. — According to nuclease S-1 resistance and kinetic renaturation curves mouse genome appears to be made up of non-repetitive DNA (76% of total DNA), middle repetitive DNA (average repetition frequency 2×104 copies, 15% of total DNA), highly repetitive DNA (8% of total DNA) and fold-back DNA (renatured density 1.701 g/ml, 1% of total DNA).— Non-repetitive sequences are intercalated with short middle repetitive sequences. One third of non-repetitive sequences is longer than 4500 nucleotides, another third is long between 1800 and 4500 nucleotides, and the remainder is shorter than 1800 nucleotides. —Middle repetitive sequences are transcribed in vivo. The majority of the transcribed repeated sequences appears to be not linked to the bulk of non-repeated sequences at a DNA size of 1800 nucleotides. — The organization of mouse genome analyzed by Ag+-Cs2SO4 density gradient of reannealed DNA appears to be substantially different than that previously observed in human genome using the same technique. 相似文献
3.
Combined field surveys and laboratory studies were conducted in two Italian coastal lagoons, which differ for geomorphology,
hydrodynamics and eutrophication degree (Sacca di Goro and Lesina lagoons, Adriatic Sea). Research aimed at assessing with
a rapid technique the potential buffering capacity of sedimentary iron towards sulphides. In Spring and Summer 2004, the main
pools of iron and sulphides were analysed in the uppermost sediment horizon (0–5 cm) at four stations in each lagoon. In parallel,
experiments with laboratory incubations of sediment slurries were carried out at two sites in each lagoon in order to assess
the sediment capacity of binding and retaining sulphides. Sediment slurries were kept stirred and anoxic with N2 purging. Aliquots of dissolved sulphides (DS) were then added and DS concentrations were monitored until they were undetectable.
On average, the total reactive iron (RFe), extracted with 6 N HCl, ranged from 170 to 400 μmol cm−3 in the Sacca di Goro stations, and comprised between 40 and 150 μmol cm−3 in the Lesina sites. The labile iron ferric quota (LFe: extractable with 0.5 N HCl) is considered representative of the microbially
reducible iron fraction and was highest in spring in Sacca di Goro (up to 20 μmol cm−3). Differences among stations evidenced by PCA analysis, can be inferred from RFe, LFe and AVS, which represent the iron buffer
and its saturation status, respectively. The sedimentary DS uptake was 6 μmol cm−3 of fresh sediment in Lesina and 8–12 μmol cm−3 in Sacca di Goro, indicating a direct relationship between DS removal and iron availability.
Guest editors: A. Razinkovas, Z. R. Gasiūnaitė, J. M. Zaldivar & P. Viaroli
European Lagoons and their Watersheds: Function and Biodiversity 相似文献
4.
Oxygenation measurement by multi‐wavelength oxygen‐dependent phosphorescence and delayed fluorescence: catchment depth and application in intact heart 下载免费PDF全文
Gianmarco M. Balestra Maurice C.G. Aalders Patricia A.C. Specht Can Ince Egbert G. Mik 《Journal of biophotonics》2015,8(8):615-628
Oxygen delivery and metabolism represent key factors for organ function in health and disease. We describe the optical key characteristics of a technique to comprehensively measure oxygen tension (PO2) in myocardium, using oxygen‐dependent quenching of phosphorescence and delayed fluorescence of porphyrins, by means of Monte Carlo simulations and ex vivo experiments. Oxyphor G2 (microvascular PO2) was excited at 442 nm and 632 nm and protoporphyrin IX (mitochondrial PO2) at 510 nm. This resulted in catchment depths of 161 (86) µm, 350 (307) µm and 262 (255) µm respectively, as estimated by Monte Carlo simulations and ex vivo experiments (brackets). The feasibility to detect changes in oxygenation within separate anatomical compartments is demonstrated in rat heart in vivo.
5.
Chiara Barbieri Paul Heggarty Daniele Yang Yao Gianmarco Ferri Sara De Fanti Stefania Sarno Graziella Ciani Alessio Boattini Donata Luiselli Davide Pettener 《American journal of physical anthropology》2014,155(4):600-609
The Yanesha are a Peruvian population who inhabit an environment transitional between the Andes and Amazonia. They present cultural traits characteristic of both regions, including in the language they speak: Yanesha belongs to the Arawak language family (which very likely originated in the Amazon/Orinoco lowlands), but has been strongly influenced by Quechua, the most widespread language family of the Andes. Given their location and cultural make‐up, the Yanesha make for an ideal case study for investigating language and population dynamics across the Andes‐Amazonia divide. In this study, we analyze data from high and mid‐altitude Yanesha villages, both Y chromosome (17 STRs and 16 SNPs diagnostic for assigning haplogroups) and mtDNA data (control region sequences and 3 SNPs and one INDEL diagnostic for assigning haplogroups). We uncover sex‐biased genetic trends that probably arose in different stages: first, a male‐biased gene flow from Andean regions, genetically consistent with highland Quechua‐speakers and probably dating back to Inca expansion; and second, traces of European contact consistent with Y chromosome lineages from Italy and Tyrol, in line with historically documented migrations. Most research in the history, archaeology and linguistics of South America has long been characterized by perceptions of a sharp divide between the Andes and Amazonia; our results serve as a clear case‐study confirming demographic flows across that ‘divide’. Am J Phys Anthropol 155:600–609, 2014. © 2014 The Authors. American journal of physical Anthropology published by Wiley Periodocals, Inc. 相似文献
6.
Prunotto M Ghiggeri G Bruschi M Gabbiani G Lescuyer P Hocher B Chaykovska L Berrera M Moll S 《Journal of Proteomics》2011,74(10):1855-1870
Renal tubulo-interstitial fibrosis is a non-specific process, representing the final common pathway for all kidney diseases, irrespective of their initial cause, histological injury, or etiology, leading to gradual expansion of the fibrotic mass which destroys the normal structure of the tissue and results in organ dysfunction and, ultimately, in end-stage organ failure. Proteomic studies of the fibrotic pathophysiological mechanisms have been performed in cell cultures, animal models and human tissues, addressing some of the key issues. This article will review proteomic contribution to the raising current knowledge on renal fibrosis biology and also mention seminal open questions to which proteomic techniques and proteomists could fruitfully contribute. 相似文献
7.
Graft union formation in artichoke grafting onto wild and cultivated cardoon: An anatomical study 总被引:1,自引:0,他引:1
Alessandra Trinchera Gianmarco Pandozy Simona Rinaldi Paola Crinò Olindo Temperini Elvira Rea 《Journal of plant physiology》2013
In order to develop a non-chemical method such as grafting effective against well-known artichoke soil borne diseases, an anatomical study of union formation in artichoke grafted onto selected wild and cultivated cardoon rootstocks, both resistant to Verticillium wilt, was performed. The cardoon accessions Belgio (cultivated cardoon) and Sardo (wild cardoon) were selected as rootstocks for grafting combinations with the artichoke cv. Romolo. Grafting experiments were carried out in the autumn and spring. The anatomical investigation of grafting union formation was conducted by scanning electron microscopy (SEM) on the grafting portions at the 3rd, 6th, 10th, 12th day after grafting. For the autumn experiment only, SEM analysis was also performed at 30 d after grafting. 相似文献
8.
Gianmarco Rinaldi Erica Pranzini Joke Van Elsen Dorien Broekaert Cornelius M. Funk Mélanie Planque Ginevra Doglioni Patricia Altea-Manzano Matteo Rossi Vincent Geldhof Shao Thing Teoh Christina Ross Kent W. Hunter Sophia Y. Lunt Thomas G.P. Grünewald Sarah-Maria Fendt 《Molecular cell》2021,81(2):386-397.e7
9.
Green fluorescent protein (GFP) fusions, immunofluorescence microscopy, and cryo-electron tomography revealed that the chemoreceptors of the Lyme disease spirochete Borrelia burgdorferi form long, thin arrays near both cell poles. These arrays are in close proximity to the flagellar motors. This information provides a basis for further understanding motility, chemotaxis, and protein localization in spirochetes. 相似文献
10.
Justin D Walter Melanie Scherer Cedric A J Hutter Alisa A Garaeva Iwan Zimmermann Marianne Wyss Jan Rheinberger Yelena Ruedin Jennifer C Earp Pascal Egloff Michle Sorgenfrei Lea M Hürlimann Imre Gonda Gianmarco Meier Sille Remm Sujani Thavarasah Geert van Geest Rmy Bruggmann Gert Zimmer Dirk J Slotboom Cristina Paulino Philippe Plattet Markus A Seeger 《EMBO reports》2022,23(4)
The ongoing COVID‐19 pandemic represents an unprecedented global health crisis. Here, we report the identification of a synthetic nanobody (sybody) pair, Sb#15 and Sb#68, that can bind simultaneously to the SARS‐CoV‐2 spike RBD and efficiently neutralize pseudotyped and live viruses by interfering with ACE2 interaction. Cryo‐EM confirms that Sb#15 and Sb#68 engage two spatially discrete epitopes, influencing rational design of bispecific and tri‐bispecific fusion constructs that exhibit up to 100‐ and 1,000‐fold increase in neutralization potency, respectively. Cryo‐EM of the sybody‐spike complex additionally reveals a novel up‐out RBD conformation. While resistant viruses emerge rapidly in the presence of single binders, no escape variants are observed in the presence of the bispecific sybody. The multivalent bispecific constructs further increase the neutralization potency against globally circulating SARS‐CoV‐2 variants of concern. Our study illustrates the power of multivalency and biparatopic nanobody fusions for the potential development of therapeutic strategies that mitigate the emergence of new SARS‐CoV‐2 escape mutants. 相似文献