Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 451
Filtrar
1.
Environ Pollut ; 290: 118111, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34523529

RESUMO

Organic-matter decomposition has long been proposed as a tool to assess stream functional integrity, but this indicator largely depends on organic-matter selection. We assessed eight decomposition-based indicators along two well-known environmental gradients, a nutrient-enrichment gradient (0.2-1.4 mg DIN/L) in central Portugal and an acidification gradient (pH: 4.69-7.33) in north-eastern France to identify the most effective organic-matter indicator for assessing stream functional integrity. Functional indicators included natural leaf litter (alder and oak) in 10-mm and 0.5-mm mesh bags, commercial tea (Lipton green and rooibos teas in 0.25-mm mesh bags), wood sticks (wood tongue depressors) and cotton strips. Biotic indices based on benthic macroinvertebrates (IPtIN for Portugal and IBGN for France) were calculated to compare the effectiveness of structural and functional indicators in detecting stream impairment and to assess the relationship between both types of indicators. The effectiveness of organic-matter decomposition rates as a functional indicator depended on the stressor considered and the substrate used. Decomposition rates generally identified nutrient enrichment and acidification in the most acidic streams. Decomposition rates of alder and oak leaves in coarse-mesh bags, green and rooibos teas and wood sticks were positively related with pH. Only decomposition rates of rooibos tea and wood sticks were related with DIN concentration; decomposition rates along the nutrient-enrichment gradient were confounded by differences in shredder abundance and temperature among streams. Stream structural integrity was good to excellent across streams; the IPtIN index was unrelated to DIN concentration, while the IBGN index was positively related with pH. The relationships between decomposition rates and biotic indices were loose in most cases, and only decomposition rates of alder leaves in coarse-mesh bags and green tea were positively related with the IBGN. Commercial substrates may be a good alternative to leaf litter to assess stream functional integrity, especially in the case of nutrient enrichment.


Assuntos
Alnus , Rios , Ecossistema , Folhas de Planta , Portugal , Madeira
2.
Molecules ; 26(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201712

RESUMO

Alnus sibirica (AS) is distributed in Korea, Japan, China, and Russia and has reported anti-oxidant, anti-inflammatory, and reducing activities on atopic dermatitis-like skin lesions, along with other beneficial health properties. In the present study, we tried to prove the cancer-preventive activity against prostate cancer. The extracted and isolated compounds, oregonin (1), hirsutenone (2), and hirsutanonol (3), which were isolated from AS, were tested for anti-proliferative activity. To do this, we used the MTT assay; NF-κB inhibitory activity, using Western blotting; apoptosis-inducing activity using flow cytometry; DNA methylation activity, using methylation-specific polymerase chain reaction in androgen-dependent (LNCaP) and androgen-independent (PC-3) prostate cancer cell lines. The compounds (1-3) showed potent anti-proliferative activity against both prostate cancer cell lines. Hirsutenone (2) exhibited the strongest NF-κB inhibitory and apoptosis-inducing activities compared with oregonin (1) and hirsutanonol (3). DNA methylation activity, which was assessed for hirsutenone (2), revealed a concentration-dependent enhancement of the unmethylated DNA content and a reduction in the methylated DNA content in both PC-3 and LNCaP cells. Overall, these findings suggest that hirsutenone (2), when isolated from AS, may be a potential agent for preventing the development or progression of prostate cancer.


Assuntos
Alnus/química , Apoptose/efeitos dos fármacos , Catecóis/farmacologia , Proliferação de Células/efeitos dos fármacos , Desmetilação do DNA/efeitos dos fármacos , Diarileptanoides/farmacologia , Glutationa S-Transferase pi/metabolismo , Neoplasias da Próstata/prevenção & controle , Androgênios/farmacologia , Catecóis/química , Catecóis/isolamento & purificação , Linhagem Celular Tumoral , Diarileptanoides/química , Diarileptanoides/isolamento & purificação , Citometria de Fluxo , Humanos , Masculino , NF-kappa B/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo
3.
J Chem Ecol ; 47(7): 680-688, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34101117

RESUMO

Past work shows a significant negative correlation between foliar oregonin concentration and western tent caterpillar (Malacosoma californicum Packard) feeding on red alder (Alnus rubra Bong.). Above an oregonin threshold of 20% leaf dry weight, little feeding by caterpillars is observed. Concentrations of defensive chemicals are influenced by plant genotype, environmental conditions, insect feeding, and the interactions of these factors. Our objective was to measure the effects of nitrogen (N) availability and wounding on foliar oregonin and condensed tannin concentrations in red alder genotypes. One-year-old seedlings from 100 half-sib red alder families were treated with two levels of ammonium nitrate (NH4NO3) for two growing seasons in a common garden. In the second year, leaves from 50 families from the fertilization experiment were used in a bioassay feeding experiment to determine the effects of N fertilization and genotype on WTC damage, and to identify a subset of 20 families with a range of damage to analyze for phytochemical composition. In separate experiments, wound-induction treatments were conducted outdoors and, in a greenhouse using the N treated trees in their third and fourth year, respectively. Foliar condensed tannin, oregonin and N concentrations were measured and ranked among the plant genotypes, and between the two N treatments and two wounding treatments. Results showed that oregonin and condensed tannin concentrations varied among the alder genotypes. Leaf N concentration was negatively correlated with concentration of oregonin. Neither of the measured phenolic compounds responded to wounding. The results suggest that red alder foliar oregonin and condensed tannin are likely constitutive defenses that are largely determined by genotype, and that the negative correlation of defense compounds with plant internal N status holds in this N-fixing tree.


Assuntos
Alnus/química , Diarileptanoides/química , Mariposas/efeitos dos fármacos , Compostos Fitoquímicos/farmacologia , Taninos/análise , Alnus/genética , Alnus/crescimento & desenvolvimento , Animais , Cromatografia Líquida de Alta Pressão , Diarileptanoides/farmacologia , Fertilizantes/análise , Genótipo , Herbivoria/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Mariposas/fisiologia , Nitrogênio/química , Nitrogênio/metabolismo , Compostos Fitoquímicos/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Plântula , Espectrofotometria Ultravioleta , Taninos/farmacologia
4.
Sci Total Environ ; 783: 147013, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-33872895

RESUMO

Human activities have greatly extended and intensified freshwater salinization, which threatens the structure and functioning of streams and rivers. Research on salt effects on in-stream processes has been strongly biased towards chronic salinization at constant levels. The aim of this study was to assess microbial mediated decomposition of two leaf species contrasting in quality (alder and oak) and associated descriptors, during salt-pulsed contamination (salinization period) and after cessation of salt additions (recovery period). Leaves were incubated in a mountain stream (central Portugal) longitudinally divided over 22 m. Half of the stream (salinized half) was subjected to daily short-term sharp salinity increases (conductivity up to ~48 mS cm-1) during 7 days while the other half (control half) was used as control. During the salinization period, salt exposure negatively affected mass loss and microbial respiration rate of alder (high-quality resource) while effects on fungal sporulation rate were independent of leaf quality. Fungal biomass was not impacted. After the recovery period, mass loss and respiration rate in both leaf species were similar between experimental stream halves. Fungal biomass associated with oak was enhanced and sporulation rate of alder, maintained in the previously salinized half, remained depressed. These results point out that the effects of salt pulses may be more deleterious in streams exclusively lined by high (vs. low) quality riparian trees as a result of a less efficient microbial-mediated leaf processing, and a reduced contribution to the conidial pool, even beyond the salinization period.


Assuntos
Alnus , Rios , Fungos , Humanos , Folhas de Planta , Portugal , Salinidade
5.
Acta Biomed ; 92(1): e2021037, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33682836

RESUMO

BACKGROUND Usually, the number of injections required to achieve the maintenance dose in subcutaneous immunotherapy (SCIT) is relatively small for some of the currently used allergens, but this may still be uncomfortable for patients, thus compromising adherence and compliance. OBJECTIVE The purpose of this study was to evaluate the safety and tolerability of a dose acceleration of a conventional induction schedule using an allergoid extract of grass pollen, birch, hazel, and alder, needed to achieve the ideal maintenance dose. METHODS In this open-label study, 34 patients with allergic rhinoconjunctivitis, with or without asthma, were treated with SCIT using an allergoid for grass pollen or birch or mix trees with an increase in accelerated induction dose comprising only 3 injections, one per week, compared to a conventional induction pattern in five injections (once a week). Safety determination was assessed by evaluating local and systemic adverse events. Tolerability was evaluated by patients and physicians who performed the treatment. RESULTS No treatment-related adverse events were observed in any of the patients undergoing rush SCIT. No local reactions, no systemic reactions of any degree (WAO Grade) have been observed. Tolerability has always been rated as very good by both patients and physician. CONCLUSIONS The induction phase, needed to achieve the monthly maintenance dose for a pollen extract, can be greatly accelerated, ensuring a tolerability comparable to that of the conventional schedule.


Assuntos
Alnus , Asma , Rinite Alérgica Sazonal , Alérgenos , Alergoides , Asma/terapia , Betula , Criança , Humanos , Poaceae , Pólen , Rinite Alérgica Sazonal/terapia
6.
J Chem Ecol ; 47(2): 215-226, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33475940

RESUMO

Plants synthesize a wide range of bioactive secondary metabolites to defend against pests and pathogens. Red alder (Alnus rubra) bark, root, and leaf extract have a long history of use in traditional medicine and hygiene. Diarylheptanoids, especially oregonin ((5S)-1,7-bis(3,4-dihydroxyphenyl)-5-(ß-D-xylopyranosyloxy)-heptan-3-one), have been identified as major bioactive constituents. Diarylheptanoids have become a focus of research following reports of their antioxidant, antifungal, and anti-cancer activities. Recent data suggest that high oregonin concentration is associated with resistance of red alder leaves to western tent caterpillar (Malacosoma californicum) defoliation. Here we test effects of this compound directly on leaf-eating insects. Purified oregonin was examined in insect choice and toxicity tests using lepidopteran caterpillars. The compound exhibited significant anti-feedant activity against cabbage looper (Trichoplusia ni), white-marked tussock moth (Orgyia leucostigma), fall webworm (Hyphantria cunea), and M. californicum at concentrations corresponding to oregonin content of the most resistant alder clones in previous experiments. Toxicity tests were carried out with cabbage looper larvae only, but no contact or ingested toxicity was detected. Our results suggest that oregonin at levels found in red alder leaves early in the growing season may contribute to protecting red alder from leaf-eating insects.


Assuntos
Alnus/metabolismo , Diarileptanoides/metabolismo , Herbivoria , Mariposas/fisiologia , Animais , Casca de Planta/metabolismo , Folhas de Planta/metabolismo , Testes de Toxicidade
7.
Phytochem Anal ; 32(4): 554-561, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33094496

RESUMO

INTRODUCTION: The diarylheptanoid xyloside oregonin ((5S)-1,7-bis(3,4-dihydroxyphenyl)-5-(ß-d-xylopyranosyloxy)-heptan-3-one) has significant medicinal potential and is found at high concentration in leaves and bark of red alder (Alnus rubra). OBJECTIVES: To establish inexpensive and easily scaled methods for the extraction and purification of oregonin from timber by-products. METHODS: We developed a method combining aqueous extraction with spray drying of red alder extract into a powder, thus reducing the need for organic solvents used in traditional Soxhlet extraction or in solvent partitioning. Flash chromatography was utilised to purify oregonin from crude spray-dried alder extract. RESULTS: Crude spray-dried alder extract was comprised of an average of 9% of the diarylheptanoid compound oregonin. Less than 10% thermal degradation of oregonin was observed using extraction temperatures between 25°C and 50°C, followed by spray drying. The structure of purified oregonin was validated using high-performance liquid chromatography (HPLC), mass spectrometry (MS), ultraviolet spectroscopy (UV), and nuclear magnetic resonance (NMR). CONCLUSION: The developed method was robust, repeatable, and yielded purified oregonin of greater than > 95% purity (average of 95.8%). Our analysis represents the most complete NMR characterisation of oregonin reported to date.


Assuntos
Alnus , Diarileptanoides , Casca de Planta , Folhas de Planta , Secagem por Atomização
8.
Ann Bot ; 127(3): 337-346, 2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33211793

RESUMO

BACKGROUND AND AIMS: Forest peatlands represent 25 % of global peatlands and store large amounts of carbon (C) as peat. Traditionally they have been drained in order to increase forestry yield, which may cause large losses of C from the peat. Rewetting aims to stop these losses and to restore the initial storage function of the peatlands. As roots represent major peat-forming elements in these systems, we sampled roots with diameter <5 mm in a drained and a rewetted forest peatland in north-east Germany to evaluate differences in tree biomass investments below ground, root functional characteristics and root age. METHODS: We cored soil next to Alnus glutinosa stems and sorted root biomass into <1, 1-2 and 2-5 mm diameter classes. We measured biomass distribution and specific root area (SRA) in 10-cm depth increments down to 50 cm, and estimated root age from annual growth rings. KEY RESULTS: Root biomass in the rewetted site was more than double that in the drained site. This difference was mostly driven by very fine roots <1 mm, which accounted for 51 % of the total root biomass and were mostly (75 %) located in the upper 20 cm. For roots <1 mm, SRA did not differ between the sites. However, SRA of the 1-2 mm and 2-5 mm diameter roots was higher in the drained than in the rewetted site. Root age did not differ between sites. CONCLUSIONS: The size-dependent opposite patterns between root biomass and their functional characteristics under contrasting water regimes indicate differences between fine and coarse roots in their response to environmental changes. Root age distribution points to similar root turnover rates between the sites, while higher root biomass in the rewetted site clearly indicates larger tree C stocks below ground under rewetting, supporting the C sink function of the ecosystem.


Assuntos
Alnus , Biomassa , Ecossistema , Florestas , Raízes de Plantas , Solo
9.
Int J Phytoremediation ; 23(4): 415-425, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32976720

RESUMO

Alders, as an N-fixing species, are widely used as a phytomelioration species at post-industrial sites. The paper presents the effects of litter decomposition of different alder species-black alder, gray alder, and green alder-on changes to the soil solution chemistry of Technosols developed from two types of substrates: lignite combustion waste and sandy substrates from a former sand quarry. Under controlled conditions, the 13-week experiment investigated pH, electrical conductivity (EC), and the chemical parameters-dissolved organic carbon (DOC), dissolved nitrogen (DON), and macroelements S, Ca, Mg, K, and Na content-of filtrates in composites consisting of substrate and litter from alder species was investigated. Alder litter accelerated nutrient leaching processes from soil substrates and had the greatest impact on sandy substrates because fast leaching was possible at low absorption capacity characteristics. Higher leaching rates in sandy substrates were also observed, especially in the cases of DOC, DON, K, and P, in comparison to combustion waste substrates. In the first phase of the experiment in sandy soil substrates, the dominant process is the leaching of DOC from dead organic matter, while in the case of combustion waste, calcium leaching prevails in the first phase. Among the investigated species, black alder had the greatest impact on the chemistry of substrates and solutions, and the dynamic of these processes has a different path at various substrates.


Assuntos
Alnus , Biodegradação Ambiental , Carbono , Carvão Mineral , Laboratórios , Areia , Solo
10.
Microb Ecol ; 81(1): 14-25, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32623497

RESUMO

The invasion of native riparian forests by exotic tree species can lead to profound changes in the ecological integrity of freshwater ecosystems. We assessed litter decomposition of native (Alnus glutinosa and Quercus robur) and invasive (Acacia melanoxylon and Acacia dealbata) tree species, and associated microbial activity and community structure, after being immersed for conditioning in 3 reference and 3 "invaded" streams in Serra da Lousã (central Portugal) and used in microcosms simulating stream conditions. Litter decomposition differed among species, in the order: Al. glutinosa > Q. robur > (Ac. melanoxylon ~ Ac. dealbata). Alnus glutinosa litter decomposed faster probably because it was soft and had high nitrogen concentration for decomposers. Quercus robur litter decomposed slower most likely because it was tough and had high polyphenol and low nitrogen concentrations. Acacia melanoxylon litter was the toughest and had a thick cuticle that likely acted as a physical barrier for microbial colonization. In Ac. dealbata, the small-sized leaflets and high lignin concentration may have limited microbial litter decomposition. Litter decomposition was faster in "invaded" streams, probably because they were N-limited and increases in nitrogen concentration in water, promoted by Acacia species invasion, stimulated microbial activity on litter. The aquatic hyphomycete community structure differed among litter species and between stream types, further suggesting that microbes were sensitive to litter characteristics and water nutrient concentrations. Overall, the invasion of native riparian forests by Acacia species may affect microbial decomposer activity, thus altering important stream ecosystem processes, such as litter decomposition and nutrient cycles.


Assuntos
Acacia/metabolismo , Bactérias/crescimento & desenvolvimento , Fungos/crescimento & desenvolvimento , Espécies Introduzidas , Rios/química , Rios/microbiologia , Alnus/microbiologia , Biomassa , Ecologia , Florestas , Microbiota , Fixação de Nitrogênio/fisiologia , Portugal , Quercus/microbiologia
11.
Environ Geochem Health ; 43(1): 77-89, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32728949

RESUMO

Metal(loid) pollution of soils has important negative effects on the environment and human health. For the rehabilitation of these soils, some eco-innovative strategies, such as phytoremediation, could be chosen. This practice could establish a plant cover to reduce the toxicity of the pollutants and stabilize the soil, preventing soil erosion and water leaching; this technique is called phytoremediation. For this, plants need to be tolerant to the pollutants present; thus, phytoremediation can have better outcomes if endemic species of the polluted area are used. Finally, to further improve phytoremediation success, amendments can be applied to ameliorate soil conditions. Different amendments can be used, such as biochar, a good metal(loid) immobilizer, compost, a nutrient-rich product and iron sulfate, an efficient arsenic immobilizer. These amendments can either be applied alone or combined for further positive effects. In this context, a mesocosm experiment was performed to study the effects of three amendments, biochar, compost and iron sulfate, applied alone or combined to a former mine technosol, on the soil properties and the phytoremediation potential of two endemic species, Alnus sp. and Betula sp. Results showed that the different amendments reduced soil acidity and decreased metal(loid) mobility, thus improving plant growth. Both species were able to grow on the amended technosols, but alder seedlings had a much higher growth compared to birch seedlings. Finally, the combination of compost with biochar and/or iron sulfate and the establishment of endemic alder plants could be a solution to rehabilitate a former mine technosol.


Assuntos
Alnus/metabolismo , Betula/metabolismo , Mineração , Poluentes do Solo/metabolismo , Alnus/crescimento & desenvolvimento , Betula/crescimento & desenvolvimento , Biodegradação Ambiental , Carvão Vegetal/metabolismo , Compostagem , Compostos Ferrosos/metabolismo , Humanos , Metaloides/metabolismo , Metais/metabolismo , Plântula/crescimento & desenvolvimento
12.
Allergy ; 76(6): 1743-1753, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33301602

RESUMO

BACKGROUND: In addition to known allergens, other proteins in pollen can aid the development of an immune response in allergic individuals. The contribution of the "unknown" protein allergens is apparent in phylogenetically related species where, despite of high homology of the lead allergens, the degree of allergenic potential can vary greatly. The aim of this study was to identify other potentially allergenic proteins in pollen of three common and highly related allergenic tree species: birch (Betula pendula), hazel (Corylus avellana) and alder (Alnus glutinosa). METHODS: For that purpose, we carried out a comprehensive, comparative proteomic screening of the pollen from the three species. In order to maximize protein recovery and coverage, different protein extraction and isolation strategies during sample preparation were employed. RESULTS: As a result, we report 2500-3000 identified proteins per each of the pollen species. Identified proteins were further used for a number of annotation steps, providing insight into differential distribution of peptidases, peptidase inhibitors and other potential allergenic proteins across the three species. Moreover, we carried out functional enrichment analyses that, interestingly, corroborated high species similarity in spite of their relatively distinct protein profiles. CONCLUSION: We provide to our knowledge first insight into proteomes of two very important allergenic pollen types, hazel and alder, where not even transcriptomics data are available, and compared them to birch. Datasets from this study can be readily used as protein databases and as such serve as basis for further functional studies.


Assuntos
Alnus , Corylus , Alérgenos , Betula , Humanos , Pólen , Proteômica , Árvores
13.
Tree Physiol ; 41(7): 1122-1142, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33367874

RESUMO

Highly host-specific eriophyoid gall- and erineum-forming mites infest a limited range of broadleaf species, with the mites from the genus Eriophyes particularly widespread on Alnus spp. and Tilia spp. Once infected, the infections can be massive, covering a large part of leaf area and spreading through the plant canopy, but the effects of Eriophyes mite gall formation on the performance of host leaves are poorly understood. We studied the influence of three frequent Eriophyes infections, E. inangulis gall-forming mites on Alnus glutinosa, and E. tiliae gall-forming and E. exilis erineum-forming mites on Tilia cordata, on foliage morphology, chemistry, photosynthetic characteristics, and constitutive and induced volatile emissions. For all types of infections, leaf dry mass per unit area, net assimilation rate per area and stomatal conductance strongly decreased with increasing severity of infection. Mite infections resulted in enhancement or elicitation of emissions of fatty acid-derived volatiles, isoprene, benzenoids and carotenoid breakdown products in an infection severity-dependent manner for all different infections. Monoterpene emissions were strongly elicited in T. cordata mite infections, but these emissions were suppressed in E. inangulis-infected A. glutinosa. Although the overall level of mite-induced emissions was surprisingly low, these results highlight the uniqueness of the volatile profiles and offer opportunities for using volatile fingerprints and overall emission rates to diagnose infections by Eriophyes gall- and erineum-forming mites on temperate trees and assess their impact on the physiology of the affected trees.


Assuntos
Alnus , Ácaros , Animais , Fotossíntese , Folhas de Planta , Tilia , Árvores
14.
Syst Appl Microbiol ; 43(6): 126134, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33059155

RESUMO

We describe a new Frankia species, for three non-isolated strains obtained from Alnus glutinosa in France and Sweden, respectively. These strains can nodulate several Alnus species (A. glutinosa, A. incana, A. alnobetula), they form hyphae, vesicles and sporangia in the root nodule cortex but have resisted all attempts at isolation in pure culture. Their genomes have been sequenced, they are significantly smaller than those of other Alnus-infective species (5Mb instead of 7.5Mb) and are very closely related to one another (ANI of 100%). The name Candidatus Frankia nodulisporulans is proposed. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene and draft genome sequences reported in this study for AgTrS, AgUmASt1 and AgUmASH1 are MT023539/LR778176/LR778180 and NZ_CADCWS000000000.1/CADDZU010000001/CADDZW010000001, respectively.


Assuntos
Alnus/microbiologia , Frankia/classificação , Filogenia , Nódulos Radiculares de Plantas/microbiologia , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , França , Frankia/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Suécia
15.
Int J Syst Evol Microbiol ; 70(10): 5453-5459, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32910750

RESUMO

The members of the genus Frankia are, with a few exceptions, a group of nitrogen-fixing symbiotic actinobacteria that nodulate mostly woody dicotyledonous plants belonging to three orders, eight families and 23 genera of pioneer dicots. These bacteria have been characterized phylogenetically and grouped into four molecular clusters. One of the clusters, cluster 1 contains strains that induce nodules on Alnus spp. (Betulaceae), Myrica spp., Morella spp. and Comptonia spp. (Myricaceae) that have global distributions. Some of these strains produce not only hyphae and vesicles, as other cluster 1 strains do, but also numerous sporangia in their host symbiotic tissues, hence their phenotype being described as spore-positive (Sp+). While Sp+ strains have resisted repeated attempts at cultivation, their genomes have recently been characterized and found to be different from those of all described species, being markedly smaller than their phylogenetic neighbours. We thus hereby propose to create a 'Candidatus Frankia alpina' species for some strains present in nodules of Alnus alnobetula and A. incana that grow in alpine environments at high altitudes or in subarctic environments at high latitudes.


Assuntos
Alnus/microbiologia , Frankia/classificação , Fixação de Nitrogênio , Filogenia , Nódulos Radiculares de Plantas/microbiologia , Técnicas de Tipagem Bacteriana , Magnoliopsida/microbiologia , Simbiose
16.
PLoS One ; 15(9): e0238004, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32877417

RESUMO

Fire severity affects both ecosystem N-loss and post-fire N-balance. Climate change is altering the fire regime of interior Alaska, although the effects on Siberian alder (Alnus viridis ssp. fruticosa) annual N-fixation input (kg N ha-1 yr-1) and ecosystem N-balance are largely unknown. We established 263 study plots across two burn scars within the Yukon-Tanana Uplands ecoregion of interior Alaska. Siberian alder N-input was quantified by post-fire age, fire severity, and stand type. We modeled the components of Siberian alder N-input using environmental variables and fire severity within and across burn scars and estimated post-fire N-balance using N-loss (volatilized N) and N-gain [biological N-fixation and atmospheric deposition]. Mean nodule-level N-fixation rate was 70% higher 11-years post-fire (12.88 ± 1.18 µmol N g-1 hr-1) than 40-years post-fire (7.58 ± 0.59 µmol N g-1 hr-1). Structural equation modeling indicated that fire severity had a negative effect on Siberian alder density, but a positive effect on live nodule biomass (g nodule m-2 plant-1). Post-fire Siberian alder N-input was highest in 11-year old moderately burned deciduous stands (11.53 ± 0.22 kg N ha-1 yr-1), and lowest in 11-year old stands that converted from black spruce to deciduous dominance after severe fire (0.06 ± 0.003 kg N ha-1 yr-1). Over a 138-year fire return interval, N-gains in converted black spruce stands are estimated to offset 15% of volatilized N, whereas N-gains in burned deciduous stands likely exceed volatilized N by an order of magnitude. High Siberian alder density and nodule biomass drives N-input in burned deciduous stands, while low N-fixer density (including Siberian alder) limits N-input in high severity black spruce stands not underlain by permafrost. A severe fire regime that converts black spruce stands to deciduous dominance without alder recruitment may induce progressive N-losses which alter boreal forest ecosystem patterns and processes.


Assuntos
Alnus/crescimento & desenvolvimento , Ecossistema , Incêndios , Fixação de Nitrogênio , Nitrogênio/análise , Nitrogênio/metabolismo , Árvores/crescimento & desenvolvimento , Alaska , Alnus/metabolismo , Taiga , Árvores/metabolismo
17.
Genes (Basel) ; 11(7)2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32659930

RESUMO

Diploid Alnus glutinosa s. str. and autotetraploid A. rohlenae form a narrow hybrid zone in a study area in southern Serbia, which results in triploid hybrid formation. The vast majority of previous studies have been focused on studies of maternal plants, but the offspring resulting from their crossing have not been much studied. Here, we use the variability of microsatellites and chloroplast DNA between these species and their putative hybrids to create an overall picture of the development of the hybrid zone and its predicted type. To elucidate the gene transfer within both species, the origins of individual ploidies and especially the role of triploid hybrids, a germination experiment was carried out linked with a flow cytometry study of the resulting seedlings. The tension zone model seems to offer the most adequate explanation of our observations, with selection against triploid hybrids and the spatial positioning of the hybrid zone. Despite selection against them, the triploid hybrids play an important role in the exchange of genes between the two species and therefore serve as a bridge for introgression. The presence of fertile triploids is essential for enriching the haplotype diversity between these species and for the development of new genetic lineages.


Assuntos
Alnus/genética , Introgressão Genética , Genoma de Cloroplastos , Repetições de Microssatélites , Variação Genética , Poliploidia , Seleção Genética
18.
Molecules ; 25(15)2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32717959

RESUMO

In the present study, we isolated a lignan ((-)-(2R,3R)-1,4-O-diferuloylsecoisolariciresinol, DFS) from Alnus japonica and evaluated its antiobesity potential in vitro. We also determined its mechanism of action in a mouse pre-adipocyte 3T3-L1 cell line. DFS dose- and day-dependently inhibited adipogenesis by downregulation of adipogenic factors and lipid metabolism-regulating factors during adipocyte differentiation. In particular, DFS suppressed cell cycle-regulating factors and induced G0/G1 cell cycle arrest, implying that it had an inhibitory effect on mitotic clonal expansion which occurred at an early stage of adipogenesis. DFS also suppressed adipogenesis through decreasing Akt phosphorylation and increasing the level of Forkhead box protein-O1 (FOXO1). These results suggest that DFS may be a pharmacological candidate for the development of antiobesity, therapeutic, and nutraceutical products.


Assuntos
Adipogenia/efeitos dos fármacos , Alnus/química , Proteína Forkhead Box O1/metabolismo , Lignanas/farmacologia , Regulação para Cima , Células 3T3-L1 , Animais , Ciclo Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Camundongos , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo
19.
Sci Rep ; 10(1): 9864, 2020 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-32555419

RESUMO

This study investigated the potential role of a nitrogen-fixing early-coloniser Alnus Nepalensis D. Don (alder) in driving the changes in soil bacterial communities during secondary succession. We found that bacterial diversity was positively associated with alder growth during course of ecosystem development. Alder development elicited multiple changes in bacterial community composition and ecological networks. For example, the initial dominance of actinobacteria within bacterial community transitioned to the dominance of proteobacteria with stand development. Ecological networks approximating species associations tend to stabilize with alder growth. Janthinobacterium lividum, Candidatus Xiphinematobacter and Rhodoplanes were indicator species of different growth stages of alder. While the growth stages of alder has a major independent contribution to the bacterial diversity, its influence on the community composition was explained conjointly by the changes in soil properties with alder. Alder growth increased trace mineral element concentrations in the soil and explained 63% of variance in the Shannon-diversity. We also found positive association of alder with late-successional Quercus leucotrichophora (Oak). Together, the changes in soil bacterial community shaped by early-coloniser alder and its positive association with late-successional oak suggests a crucial role played by alder in ecosystem recovery of degraded habitats.


Assuntos
Alnus/crescimento & desenvolvimento , Alnus/microbiologia , Bactérias/metabolismo , Ecossistema , Microbiologia do Solo , Biodiversidade , Fenômenos Químicos , Fixação de Nitrogênio , Solo/química
20.
Int J Biometeorol ; 64(10): 1637-1647, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32507988

RESUMO

Alnus pollen has been frequently detected in the atmosphere of different airborne sampling sites of Southern Spain. However, Alnus sp. populations are very scarce and fragmented in the area, being restricted to a few river valleys in the southwest, and other further away regions of the Iberian Peninsula. This leads to think that the airborne pollen detected could be mainly the result of a medium- or long-distant transport. So, the aim of this study was to characterize the annual patterns of airborne Alnus pollen detected at three different locations of Malaga province, as well as to determine its possible origin, the pollen dispersion potential of these Alnus isolated populations, and their possible reproductive connectivity. Pollen sampling was conducted by means of three Hirst-type volumetric pollen traps. Samples were mounted and counted following the recommendations of the Spanish Aerobiology Network and the European Aeroallergen Society. The possible pollen sources were detected by means of a combination of meteorological information and backward air trajectories analysis. A high inter-annual variability in the annual pollen integrals was found in all the stations, favouring certain meteorological conditions a long-range transport and, therefore, causing the high concentrations detected in some specific days. Alnus pollen seems to have a heterogeneous origin with prevalence of the long-distant transport, which would suggest a possible reproductive connection among distant populations.


Assuntos
Alnus , Alérgenos , Monitoramento Ambiental , Europa (Continente) , Pólen , Estações do Ano , Espanha
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...