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1.
Casearia sylvestris Sw. is a widespread neotropical tree utilized in popular medicine. Recent research ranked Casearia as one of the most promising genus in the search of drugs against cancer. Despite its wide distribution and pharmacological importance, no microsatellite markers have yet been developed for this genus. In this study, we provide 10 polymorphic microsatellite loci specifically designed for C. sylvestris, used to analyse 90 individuals distributed in two populations from São Paulo state, Brazil. On average, 12.3 alleles per locus were identified, showing the ability of the markers to detect microsatellite polymorphism in this species.  相似文献   

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Historical tectonism and climate oscillations can isolate and contract the geographical distributions of many plant species, and they are even known to trigger species divergence and ultimately speciation. Here, we estimated the nucleotide variation and speciation in three closely related Populus species, Populus tremuloides, P. tremula and P. davidiana, distributed in North America and Eurasia. We analysed the sequence variation in six single‐copy nuclear loci and three chloroplast (cpDNA) fragments in 497 individuals sampled from 33 populations of these three species across their geographic distributions. These three Populus species harboured relatively high levels of nucleotide diversity and showed high levels of nucleotide differentiation. Phylogenetic analysis revealed that P. tremuloides diverged earlier than the other two species. The cpDNA haplotype network result clearly illustrated the dispersal route from North America to eastern Asia and then into Europe. Molecular dating results confirmed that the divergence of these three species coincided with the sundering of the Bering land bridge in the late Miocene and a rapid uplift of the Qinghai‐Tibetan Plateau around the Miocene/Pliocene boundary. Vicariance‐driven successful allopatric speciation resulting from historical tectonism and climate oscillations most likely played roles in the formation of the disjunct distributions and divergence of these three Populus species.  相似文献   

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The emergence of multidrug resistant pathogens threatened the clinical efficacy of many existing antibiotics. This situation has been recognized globally as a serious concern and justifies further research to discover antimicrobial agents from natural origins including plant extracts. The aim of our work was to evaluate the antimicrobial activities of Scabiosa arenaria Forssk . extracts and pure compounds using a bioguided fractionation, and try to explain some traditional use of this genus. The best antimicrobial activity‐guided fractionation was obtained by BuOH fractions of flowers, fruits and (stems and leaves) against Escherichia coli, Pseudomonas aeruginosa and Candida albicans with minimum inhibitory concentration (MIC) values from 0.0195 to 5 mg/ml. Escherichia coli was the most affected bug, thus the MIC of fruits BuOH extract showed the best anti‐Escherichia coli activity (MIC = 0.0195 mg/ml), followed by the (stems and leaves) and flowers BuOH extracts; MIC = 0.078 and 0.15 mg/ml, respectively. Furthermore, the subfractions obtained from these three mixed fractions showed also an important antimicrobial activity against the three microorganisms, with MIC values between 0.0195 and 0.312 mg/ml. The fractionation of the aerial part BuOH fraction led to the isolation of oleanolic acid ( 1 ) and luteolin 7‐O‐glucopyranoside ( 2 ) which are reported here for the first time from Sarenaria. Both compounds showed good antimicrobial activities with MIC values ranging from 170 to 683 μm and 86 to 347 μm , respectively. These results support the use of the Scabiosa genus to inhibit the growth of tested pathogenic bacteria and yeasts which may reduce illnesses associated with their exposure.  相似文献   

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The study of the MeOH extract of the leaves of Campylospermum excavatum led to the isolation of a nitrile glucoside, named campyloside C ( 1 ) and an original derivative of ochnaflavone, 7‐O‐methylochnaflavone ( 2 ), along with three known biflavonoids, amentoflavone, sequoiaflavone, and sotetsuflavone ( 3 – 5 ). The linkage site of the sub‐units of 2 was confirmed by chemical correlation, after semi‐synthesis of a trimethoxylated derivative of ochnaflavone ( 2a ). The structures of these compounds as well as their relative and absolute configurations were assigned by 1D‐ and 2D‐NMR experiments, HR‐ESI‐MS and Electronic Circular Dichroism (ECD) calculations. A low‐pass J filter HMBC experiment was performed in order to define the configuration of the double bond of 1 . All of the biflavonoids were evaluated against protozoan parasites. Amentoflavone moderately inhibited the promastigote form of Leishmania infantum.  相似文献   

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Examination of material held at the Palaeontological Institute, Moscow, enables the identification of two novel chasmataspidid species: Nahlyostaspis bergstroemi gen. et sp. nov. and Skrytyaspis andersoni gen. et sp. nov. ‘Eurypterusstoermeri and ‘Tylopterellamenneri are both redescribed as chasmataspidids, having previously been assigned to Eurypterida. ‘T’. menneri is transferred to the new genus Dvulikiaspis gen. nov. An identical prosomal structure is identified in ‘Eurypterusstoermeri and Heteroaspis novojilovi from the Devonian of Germany and the two species are synonymized, with ‘Estoermeri having priority. The previous synonymy of H. novojilovi with Diploaspis casteri is rejected. The presence of ophthalmic ridges is confirmed within Diploaspididae, and new structural characteristics of their bucklers are identified.  相似文献   

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Gracilariaceae are mostly pantropical red algae and include ~230 species in seven genera. Infrafamilial classification of the group has long been based on reproductive characters, but previous phylogenies have shown that traditionally circumscribed groups are not monophyletic. We performed phylogenetic analyses using two plastid (universal plastid amplicon and rbcL) and one mitochondrial (cox1) loci from a greatly expanded number of taxa to better assess generic relationships and understand patterns of character distributions. Our analyses produce the most well‐supported phylogeny of the family to date, and indicate that key characteristics of spermatangia and cystocarp type do not delineate genera as commonly suggested. Our results further indicate that Hydropuntia is not monophyletic. Given their morphological overlap with closely related members of Gracilaria, we propose that Hydropuntia be synonymized with the former. Our results additionally expand the known ranges of several Gracilariaceae species to include Brazil. Lastly, we demonstrate that the recently described Gracilaria yoneshigueana should be synonymized as G. domingensis based on morphological and molecular characters. These results demonstrate the utility of DNA barcoding for understanding poorly known and fragmentary materials of cryptic red algae.  相似文献   

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The defatted fractions of the Faramea hyacinthina and Ftruncata (Rubiaceae) leaf MeOH extracts showed in vitro non‐cytotoxic and anti‐dengue virus serotype 2 (DENV2) activity in human hepatocarcinoma cell lineage (HepG2). Submitting these fractions to the developed RP‐SPE method allowed isolating the antiviral flavanone (2S)‐isosakuranetin‐7‐Oβ‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 1 ) from both species and yielded less active sub‐fractions. The new diastereoisomeric epimer pair (2S) + (2R) of 5,3′,5′‐trihydroxyflavanone‐7‐Oβ‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 2a / 2b ) from Fhyacinthina; the known narigenin‐7‐Oβ‐d ‐apiofuranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 3 ) from both species; rutin ( 4 ) and quercetin‐4′‐β‐d ‐O‐glucopyranosyl‐3‐O‐rutinoside ( 5 ) from Fhyacinthina, and kaempferol‐3‐O‐rutinoside ( 6 ), erythroxyloside A ( 7 ) and asperuloside ( 8 ) from Ftruncata have been isolated from these sub‐fractions. Compounds 4  –  8 are reported for the first time in Faramea spp.  相似文献   

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Pinus palustris (longleaf pine) savannas depend on contiguous grass cover to facilitate frequent surface fires. Enhanced flowering, seed production, and germination may be linked to season of fires. We assessed the effect of month of prescribed fire (February, April, May, and July) on percentage of plants with flowering culms (FCs%), FC/area, FC/plant, seed production, and germination for five warm seasons, fall‐flowering grasses. Multivariate analysis indicated the response of flowering and fruiting to burn month varied among the grass species. The dominant species, Sporobolus junceus and Schizachyrium scoparium var. stoloniferum, had greater numbers of most flowering characteristics when burnt during April, May, and July. Aristida purpurascens had increased FC/plant after May and July burns. In contrast, Ar. mohrii had the fewest FC/plant and seeds/FC when burnt in July. Germination was greatest (26–60%) for Ar. purpurascens. Seeds collected following July burns for Ar. purpurascens and Ar. ternarius and after May burns for S. junceus were within the highest germination values recorded. Germination of Sc. scoparium var. stoloniferum was very low after February and July burns (≤5%). With Ar. mohrii, only seed collected following February (2%) and April burns (3%) germinated. April, May, and July fires increased seed production of dominant matrix grasses, thus facilitating the potential for recruitment of these species and facilitating seed collection from potential donor sites for ground‐layer restoration projects. Varying prescribed fire burn month captured variation in flowering characteristics among these grasses.  相似文献   

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Currently, the control of termites is mainly carried out with the use of chemical pesticides, which although effective, pose risks to the environment and to human beings. An alternative to using such chemical pesticides is natural products such as essential oils in insecticidal action. Despite the fact of being effective, essential oils are unstable, poorly soluble in water, and degrade from the action of light, oxygen even at moderate temperatures. Thus, the nanostructuring of essential oils could circumvent such problems and ensure its effectiveness. The following study aimed to assess for the first time the effects of nanostructured systems of essential oils of Cymbopogon flexuosus, Eucalyptus globulus and Melaleuca alternifolia in subterranean termites (Coptotermes gestroi). The results showed that the solid lipid nanoparticles of M. alternifolia have both repellent and insecticide action. The following study showed that nanostructuring of essential oils with insecticidal action is a promising tool in the fight against termites.  相似文献   

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Simocephalus vetulus is a large (2.0–4.0 mm at maturity) cladoceran often found in the littoral region of lakes and ponds, and capable of moderate growth rates even on poor‐quality cyanobacterial diets. It frequently co‐occurs with fishes and similar sized ostracods such as Heterocypris incongruens, but little is known of its response to fish kairomones or its interactions with potential competitors. We studied the demographic responses of S. vetulus fed the green alga Scenedesmus acutus, Microcystis cf. aeruginosa strain A, Microcystis cf. aeruginosa strain B, or Limnothrix sp. Experiments were conducted separately and together in the presence of Heterocypris incongruens and cichlid fish (Oreochromis) kairomones. A diet of Limnothrix sp. resulted in the lowest population growth rate (0.21±0.023 d?1), while on diets of S. acutus or Microcystis, population growth was higher (0.30±0.009 d?1). The presence of ostracods resulted in significantly higher growth rates of S. vetulus fed Limnothrix (0.33±0.01 d?1), but not Microcystis or S. acutus. Regardless of the diet, the presence of fish kairomones resulted in significantly higher growth rates as compared with controls, particularly when ostracods were also present. Coexistence with ostracods may be beneficial to S. vetulus, particularly when food quality is poor.  相似文献   

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This study has been aimed at providing a qualitative and quantitative evaluation of selected phytochemicals such as phenolic acids, flavonoids, oleuropein, fatty acids profile, and volatile oil compounds, present in wild olive leaves harvested in Portugal, as well as at determining their antioxidant and cytotoxic potential against human melanoma HTB‐140 and WM793, prostate cancer DU‐145 and PC‐3, hepatocellular carcinoma Hep G2 cell lines, as well as normal human skin fibroblasts BJ and prostate epithelial cells PNT2. Gallic, protocatechuic, p‐hydroxybenzoic, vanillic acids, apigenin 7‐O‐glucoside, luteolin 7‐O‐glucoside, and rutin were identified in olive leaves. The amount of oleuropein was equal to 22.64 g/kg dry weight. (E)‐Anethole (32.35%), fenchone (11.89%), and (Z)‐3‐nonen‐1‐ol (8%) were found to be the main constituents of the oil volatile fraction, whereas palmitic, oleic, and alpha‐linolenic acid were determined to be dominating fatty acids. Olive leaves methanol extract was observed to exerted a significant, selective cytotoxic effect on DU‐145 and PC‐3 cell lines. Except the essential oil composition, evaluated wild olive leaves, with regard to their quantitative and qualitative composition, do not substantially differ from the leaves of other cultivars grown for industrial purposes and they reveal considerable antioxidant and cytotoxic properties. Thus, the wild species may prove to be suitable for use in traditional medicine as cancer chemoprevention.  相似文献   

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Toxin‐producing blooms of dinoflagellates in the genus Alexandrium have plagued the inhabitants of the Salish Sea for centuries. Yet the environmental conditions that promote accelerated growth of this organism, a producer of paralytic shellfish toxins, is lacking. This study quantitatively determined the growth response of two Alexandrium isolates to a range of temperatures and salinities, factors that will strongly respond to future climate change scenarios. An empirical equation, derived from observed growth rates describing the temperature and salinity dependence of growth, was used to hindcast bloom risk. Hindcasting was achieved by comparing predicted growth rates, calculated from in situ temperature and salinity data from Quartermaster Harbor, with corresponding Alexandrium cell counts and shellfish toxin data. The greatest bloom risk, defined at μ >0.25 d?1, generally occurred from April through November annually; however, growth rates rarely fell below 0.10 d?1. Except for a few occasions, Alexandrium cells were only observed during the periods of highest bloom risk and paralytic shellfish toxins above the regulatory limit always fell within the periods of predicted bloom occurrence. While acknowledging that Alexandrium growth rates are affected by other abiotic and biotic factors, such as grazing pressure and nutrient availability, the use of this empirical growth function to predict higher risk time frames for blooms and toxic shellfish within the Salish Sea provides the groundwork for a more comprehensive biological model of Alexandrium bloom dynamics in the region and will enhance our ability to forecast blooms in the Salish Sea under future climate change scenarios.  相似文献   

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To characterize Aspergillus section Nigri strains involved in the ochratoxin A (OTA) contamination of Tunisian wine and table grapes, a total of 33 strains were analysed. A molecular characterization of the isolates was performed by the amplification of internal transcribed spacer (ITS1‐5.8S rDNA‐ITS2) region combined with amplicon sequencing. Analysis of similarity between the obtained sequences and those deposited in the GenBank database was performed. Twelve strains were confirmed to belong to the Aspergillus carbonarius species. Strains belonging to the Aspergillus niger aggregate group were classified by in silico RFLP assay into two patterns N and T, corresponding to A. niger and Aspergillus tubingensis. Among the 21 OTA producing isolates analysed, 13 showed the T‐type pattern and 8 showed the N‐type pattern. The presented method showed to be a reliable alternative to the classic RFLP method. Our findings unambiguously revealed that multiple aspergilli species isolated from wine and table grape in Tunisia are able to produce OTA.  相似文献   

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Length‐weight relationships (LWRs) are presented for three hill stream fish species belonging to the family Cyprinidae namely, Barilius barila (Hamilton, 1822), Opsarius tileo (Hamilton, 1822) and Cyprinion semiplotum (McClelland, 1839). Fishes were collected on a monthly basis from January 2016 to December 2017 with the help of cast net (270 cm length, 1.2 cm mesh size) and gillnet (7,500 cm length × 130 cm depth, 5 cm mesh size) from the Manas river in Assam, India.. A new length record for the FishBase LWR database was observed in B. barila.   相似文献   

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Besides heat stress, the 70 kDa heat shock proteins (HSP70s) have been shown to respond to cold stress. However, the involved cis‐acting elements remain unknown. The hsp70 gene from the green macroalga Ulva prolifera (Uphsp70) has been cloned, from which one heat shock element HSE and one low‐temperature‐responsive element LTR were found in the promoter. Using the established transient expression system and quantitative GUS assay, a series of element deletion experiments were performed to determine the functions of HSE and LTR in response to temperature stress. The results showed that under cold stress, both HSE and LTR were indispensable, since deletion leads to complete loss of promoter activity. Under heat stress, although the HSE could respond independently, coexistence with LTR was essential for high induced activity of the Uphsp70 promoter. Therefore, synergistic effects exist between HSE and LTR elements in response to temperature stress in Ulva, and extensive bioinformatics analysis showed that the mechanism is widespread in algae and plants, since LTR coexists widely with HSE in the promoter region of hsp70. Our findings provide important supplements to the knowledge of algal and plant HSP70s response to temperature stress. We speculated that for algal domestication and artificial breeding, HSE and LTR elements might serve as potential molecular targets to temperature acclimation.  相似文献   

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