Isoëtes sabatina (Isoëtaceae,Lycopodiopsida): Taxonomic distinctness and preliminary ecological insights     

Rossano Bolpagni  Sara Magrini  Andrea Coppi  Angelo Troìa  Janne Alahuhta  Marit Mjelde  Mattia M. Azzella 《水产资源保护:海洋与淡水生态系统》2021,31(10):2690-2696

1. Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres.
2. Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina.
3. To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species was carried out to describe its genetic distinctness, physical and chemical requirements and companion species.
4. The phylogenetic position of I. sabatina was investigated by applying standard DNA barcoding methods. Simultaneously, during summer 2019, the physical and chemical features of water and sediments of the I. sabatina population and five small Alpine lakes colonized by Isoëtes echinospora – a supposed close relative – were characterized. These data were then compared with the available data on the trophic requirements of the target obligate aquatic Isoëtes, together with Isoëtes lacustris and Isoëtes malinverniana.
5. The present survey confirmed the taxonomic and ecological distinctness of I. sabatina – providing the first evidence of genetic differentiation from I. echinospora. Isoëtes sabatina grows in waters with temperature, conductivity and total alkalinity up to 30°C, 561 μS cm⁻¹ and 3.45 meq L⁻¹, respectively.
6. The edaphic requirements of I. sabatina confirm its outstanding conservation value, and this study offers a basic understanding of how to prevent its extinction. Now, all possible actions must be taken immediately to save this species.

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Antioxidant and Antimicrobial Potential of the Bifurcaria bifurcata Epiphytic Bacteria     

André Horta  Susete Pinteus  Celso Alves  Nádia Fino  Joana Silva  Sara Fernandez  Américo Rodrigues  Rui Pedrosa 《Marine drugs》2014,12(3):1676-1689

Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.  相似文献   

Accurate Dereplication of Bioactive Secondary Metabolites from Marine-Derived Fungi by UHPLC-DAD-QTOFMS and a MS/HRMS Library     

Sara Kildgaard  Maria Mansson  Ina Dosen  Andreas Klitgaard  Jens C. Frisvad  Thomas O. Larsen  Kristian F. Nielsen 《Marine drugs》2014,12(6):3681-3705

In drug discovery, reliable and fast dereplication of known compounds is essential for identification of novel bioactive compounds. Here, we show an integrated approach using ultra-high performance liquid chromatography-diode array detection-quadrupole time of flight mass spectrometry (UHPLC-DAD-QTOFMS) providing both accurate mass full-scan mass spectrometry (MS) and tandem high resolution MS (MS/HRMS) data. The methodology was demonstrated on compounds from bioactive marine-derived strains of Aspergillus, Penicillium, and Emericellopsis, including small polyketides, non-ribosomal peptides, terpenes, and meroterpenoids. The MS/HRMS data were then searched against an in-house MS/HRMS library of ~1300 compounds for unambiguous identification. The full scan MS data was used for dereplication of compounds not in the MS/HRMS library, combined with ultraviolet/visual (UV/Vis) and MS/HRMS data for faster exclusion of database search results. This led to the identification of four novel isomers of the known anticancer compound, asperphenamate. Except for very low intensity peaks, no false negatives were found using the MS/HRMS approach, which proved to be robust against poor data quality caused by system overload or loss of lock-mass. Only for small polyketides, like patulin, were both retention time and UV/Vis spectra necessary for unambiguous identification. For the ophiobolin family with many structurally similar analogues partly co-eluting, the peaks could be assigned correctly by combining MS/HRMS data and m/z of the [M + Na]⁺ ions.  相似文献   

Aridity and geochemical drivers of soil micronutrient and contaminant availability in European drylands     

Eduardo Moreno-Jiménez  Alberto Orgiazzi  Arwyn Jones  Hugo Saiz  Sara Aceña-Heras  César Plaza 《European Journal of Soil Science》2022,73(1):e13163

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Soil texture affects soil microbial and structural recovery during grassland restoration     

Elizabeth M. Bach  Sara G. Baer  Clinton K. Meyer  Johan Six 《Soil biology & biochemistry》2010,42(12):2182-2191

Many biotic and abiotic factors influence recovery of soil communities following prolonged disturbance. We investigated the role of soil texture in the recovery of soil microbial community structure and changes in microbial stress, as indexed by phospholipid fatty acid (PLFA) profiles, using two chronosequences of grasslands restored from 0 to 19 years on silty clay loam and loamy fine sand soils in Nebraska, USA. All restorations were formerly cultivated fields seeded to native warm-season grasses through the USDA’s Conservation Reserve Program. Increases in many PLFA concentrations occurred across the silty clay loam chronosequence including total PLFA biomass, richness, fungi, arbuscular mycorrhizal fungi, Gram-positive bacteria, Gram-negative bacteria, and actinomycetes. Ratios of saturated:monounsaturated and iso:anteiso PLFAs decreased across the silty clay loam chronosequence indicating reduction in nutrient stress of the microbial community as grassland established. Multivariate analysis of entire PLFA profiles across the silty clay loam chronosequence showed recovery of microbial community structure on the trajectory toward native prairie. Conversely, no microbial groups exhibited a directional change across the loamy fine sand chronosequence. Changes in soil structure were also only observed across the silty clay loam chronosequence. Aggregate mean weighted diameter (MWD) exhibited an exponential rise to maximum resulting from an exponential rise to maximum in the proportion of large macroaggregates (>2000 μm) and exponential decay in microaggregates (<250 μm and >53 μm) and the silt and clay fraction (<53 μm). Across both chronosequences, MWD was highly correlated with total PLFA biomass and the biomass of many microbial groups. Strong correlations between many PLFA groups and the MWD of aggregates underscore the interdependence between the recovery of soil microbial communities and soil structure that may explain more variation than time for some soils (i.e., loamy fine sand). This study demonstrates that soil microbial responses to grassland restoration are modulated by soil texture with implications for estimating the true capacity of restoration efforts to rehabilitate ecosystem functions.  相似文献   

Copper localization in Cannabis sativa L. grown in a copper-rich solution     

Laura Arru  Sara Rognoni  Micaela Baroncini  Piera Medeghini Bonatti  Pierdomenico Perata 《Euphytica》2004,140(1-2):33-38

Summary With the aim to examine its potential as a renewable resource to decontaminate polluted soils, electron microscopy combined with X-ray microanalysis was used to investigate the localization of copper in Cannabis sativa grown in hydroponic copper-rich culture. Cu was found to accumulate preferentially in the upper leaf epidermal cells; it was also detected in spiculae and in abaxial trichomes too. Primary bast fibres seem to be not involved in copper accumulation.  相似文献   

从温室种植者百强榜看美国温室花卉业的过去现在未来     

Sara Tambascio  周艳萍 《中国花卉园艺》2007,(15):47-49

为了庆祝美国温室种植者百强榜的20岁生日,本文回顾了温室行业这20年来走过的岁月,展望了温室行业的未来。  相似文献   

The use of a water budget model and yield maps to characterize water availability in a landscape     

Dennis Timlin  Yakov Pachepsky  Charles Walthall  Sara Loechel 《Soil & Tillage Research》2001,58(3-4):219-231

Crop yield maps may contain substantial corollary information regarding the distribution of yield related soil properties across a landscape. One of these properties is water holding capacity (WHC). Since WHC is an important parameter for crop models and is also critical for crop yield, our objective was to determine if WHC could be estimated by matching simulated yield with yield map data. We collected soil cores for water retention measurements and recorded plant phenological stages from 60 plots on four transects over two growing seasons (1997 and 1998). Soil cores were also sampled on 40 other locations set out on a grid pattern. We utilized a simple water budget model that uses the relative transpiration ratio to calculate relative yield from available water in the soil profile. Rainfall, potential evapotranspiration and soil water holding capacity are input. An optimization program varies the WHC to produce a grain yield similar to the one from the yield map at a particular location. This analysis was carried out over several scales by averaging yields over 55 m×71 m, 27 m×35 m, and 11 m×14 m areas. Yield data from 2 years were used. Yields from the transects in both years were significantly related to measured WHC in the surface 0–10 cm of soil. The calculated stress indices from the water budget model and estimated available WHC calculated for the 1997 data were similar to those calculated for the 1998 data where data were aggregated in 27 by 35 m or larger blocks. The contour map of estimated WHC was similar to the map of measured WHC for some features though there were also some differences. Use of multiple years of yield data are required to give stable results for estimated water holding capacities.. This information could be used in a farm management plan by allowing a producer to classify a field into areas that are buffered against drought and areas more susceptible to drought.  相似文献   

Interaction of contaminated sediment from a salt marsh with estuarine water: evaluation by leaching and ecotoxicity assays and salts from leachate evaporation     

Sara Peres  M. Clara F. Magalhães  Maria Manuela Abreu  Sara Leitão  Ana Santos  Maria José Cerejeira 《Journal of Soils and Sediments》2016,16(5):1612-1624

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Crystal Structure of Hexaazaoctadecahydrocoronene Dication [HAOC]2+, a Singlet Benzene Dication     

Miller JS  Dixon DA  Calabrese JC 《Science (New York, N.Y.)》1988,240(4856):1185-1188

The structures of hexaazaoctadecahydrocoronene, [HAOC](n) (n = O, + 2), have been determined by single-crystal x-ray diffraction. Although HAOC is aromatic, its dication has a localized structure that is based upon Jahn-Teller-distorted cyanine/p-phenylenediammonium fragments. The structure is consistent with the singlet ground state as determined by magnetic susceptibility and contrasts with the simplest Hückel expectation of a triplet ground state.  相似文献