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Seeds ofDactyloctenium Willd. andEleusine Gaertn. may be distinguished from each other by spermoderm patterns.Dactyloctenium seeds are transversed by ridges crossed by wavy lines forming a verrucated, reticulate pattern.Eleusine seeds have a pitted, tuberculate spermoderm pattern. 相似文献
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Catalina VelascoCharpentier Felipe PizarroMora Nelso P. Navarro Nelson Valdivia 《Ecology and evolution》2021,11(3):1214
Habitat complexity is one of the most important factors modulating species diversity. This feature comprises several interrelated attributes, such as number, size, and spatial arrangement of complexity‐forming elements. However, the separate and joint effects of these attributes on diversity and community structure are still not well understood. Here, we assess the relationships between several structural‐complexity attributes of the subantarctic kelp Lessonia flavicans and species richness, total abundance, and structure of kelp‐associated macrobenthic communities. We predicted that longer thalli and larger holdfasts favor greater species richness and total abundance of invertebrate organisms. To test the prediction, an observational sampling program was established in two sites of the Strait of Magellan. Uni‐ and multivariate analyses revealed both positive and negative effects of kelp structural‐complexity attributes on diversity. Holdfast diameter and maximum frond length, followed by thallus wet weight, had the strongest positive fits to species richness and total abundance; the number of stipes, on the other hand, was negatively associated with both response variables. Longer fronds were associated with greater abundances of spirorbid polychaetes. Larger holdfasts supported larger abundances of Nereididae and Terebelidae polychaetes and the limpet Nacella mytilina. Contrarily, kelps with longer fronds and more stipes supported fewer amphipods. In this way, we demonstrate that different dimensions of habitat complexity can have contrasting effects on diversity and community structure, highlighting the fundamental role of multiple dimensions of kelp habitat complexity for local biodiversity. 相似文献
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Mariam Hachimi Catalina Grabowski Silvia Campanario Gonzalo Herranz Gabriel Baonza Juan M. Serrador Sergio Gomez-Lopez Maria D. Barea Minerva Bosch-Fortea Darren Gilmour Michel Bagnat Alejo E. Rodriguez-Fraticelli Fernando Martin-Belmonte 《Current biology : CB》2021,31(4):696-706.e9
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Antonio Miralles Catalina Ribas Gabriel Olmos Jesús A. García-Sevilla 《Journal of neurochemistry》1993,61(5):1602-1610
Abstract— The alkylating agent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) is a peptide-coupling agent that is being used to inactivate irreversibly α2-adrenoceptors and other receptors. The aim of the present study was to assess the in vitro and in vivo effects of EEDQ on the newly discovered brain l2-imidazoline sites, located mainly in mitochondria. Preincubation of rat cortical membranes with EEDQ (10?8-10?5M) markedly decreased (20–90%) the specific binding of the selective antagonist [3H]R821002 to α2-adrenoceptors without affecting that of [3H]idazoxan (in the presence of adrenaline) to l2-imidazoline sites. In EEDQ-pretreated membranes (10?5M, 30 min at 25°c), the density of l2-imidazoline sites (Bmax= 80 ± 4 fmol/mg of protein) was not different from that determined in untreated membranes in the presence of 10?6M (-)-adrenaline (Bmax= 83 ± 4 fmol/mg of protein), and both densities were lower (24%, p < 0.05) than the total native density of [3H]idazoxan binding sites (Bmax= 107 ± 6 fmol/mg of protein) (l2-imidazoline sites plus a2-adrenoceptors). Treatment of rats with an optimal dose of EEDQ (1.6 mg/kg, i.p., for 2 h to 30 days) reduced maximally at 6 h (by 95 ± 1%) the specific binding of [3H]-R821002 to α2-adrenoceptors, but also the binding of [3H]idazoxan to l2-imidazoline sites (by 44 ± 5%). Pretreatment with yohimbine (10 mg/kg, i.p.) fully protected against EEDQ-induced α2-adrenoceptor inactivation. In contrast, pretreatment with cirazoline (1 mg/kg, i.p.), did not protect against EEDQ-induced inactivation of l2-imidazoline sites. Treatment with EEDQ (1.6 mg/kg, i.p., for 6 h) did not alter the density of brain monoamine oxidase-A sites labeled by [3H]Ro 41–1049 or that of monoamine oxidase-B sites labeled by [3H]Ro 19–6327 (lazabemide), two relevant mitochondrial markers. Competition experiments with cirazoline against the specific binding of [3H]idazoxan to l2-imidazoline sites demonstrated the presence of the expected two affinity states for the drug in EEDQ-pretreated membranes as well as in rats treated with EEDQ. The results indicate that EEDQ in vitro is a useful tool for quantitating l2-imidazoline sites when using [3H]-imidazoline ligands that also recognize α2-adrenoceptors. In vivo, however, EEDQ is also able to inactivate partially brain l2-imidazoline sites probably by an indirect mechanism. Key Words: Brain l2-imidazoline sites—[3H]-Idazoxan—α2-Adrenoceptors—[3H] R821002—N -Ethoxycarbonyl-2-ethoxy-li2-dihydroquinoline—Monoamine oxidase-A—[3H]Ro 41–1049—Monoamine oxidase-B—[3H]Ro 19–6327. 相似文献