RESUMO
The paralepidid species Lestidiops distans (Ege, 1953) is redescribed on the basis of adult specimens collected from the eastern Atlantic Ocean. Observations on the holotype, a detailed description, and full data of the adults are provided. The complete lateral line running to the caudal fin base found in L. distans is a rare condition, with only some species in the family possessing this character. The distribution range of L. distans, from Senegal (14°N) to Namibia (22°S) along the coastline of the eastern Atlantic Ocean, is revised accordingly. Comments on a congener, Lestidiops cadenati (Maul, 1962), that co-occurs in the western Atlantic are provided.
Assuntos
Peixes , Animais , Oceano AtlânticoRESUMO
Understanding the physicochemical modulation of functional molecules is the primary step in exploring novel stimuli-responsive materials, and preventing the π-π stacking configuration of π-conjugated molecules has been an effective strategy of vapochromic material development, such as of nanoporous frameworks. Nevertheless, the more complicated synthetic strategy should in fact be applied in many circumstances. In this study, we explore a facile supramolecular strategy where the commodity plastic, syndiotactic-poly(methyl methacrylate) (st-PMMA), is utilized to wrap C60 to form the inclusion complex. The structural characterization revealed that C60s in the st-PMMA supramolecular helix had a lower coordination number (CN = 2) compared to the face-centered-cubic packing of pure C60s (CN = 12). Since the st-PMMA/C60 helical complex has structural flexibility, the π-π stacking structure of C60 was further interrupted by the intercalation of toluene vapors, and the complete isolation of C60 in the complex induced the desired vapochromic behavior. Furthermore, the aromatic interaction between C60 and aromatic solvent vapors enabled the st-PMMA/C60 inclusion complex to selectively encapsulate chlorobenzene, toluene, etc., and induce the color change. The st-PMMA/C60 inclusion complex exhibited a transparent film of sufficient structural integrity such that it can still induce a reversible color change after several cycles. As a result, a new strategy has been discovered for the development of novel vapochromic materials via host-guest chemistry.
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A strategy to obtain chiral silica using an achiral stereoregular polymer with polyhedral oligomeric silsesquioxane (POSS) side chains is described herein. The preferred helical conformation of the POSS-containing polymer could be achieved by mixing isotactic polymethacrylate-functionalized POSS (it-PMAPOSS) and a chiral dopant. The array structure of POSS molecules, which are placed along the helical conformation, is memorized even after removing the chiral dopant at high temperatures, leading to a chiral silica compound with exclusive optical activity after calcination.
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To turn on the fluorescence of the native green fluorescence protein (GFP) chromophore, 4-hydroxybenzylidene-dimethylimidazolinone (HBDI), in an artificial supramolecular system has been a challenging task, because it requires high local environmental rigidity. This work shows that the formation of H-aggregates of an HBDI-containing organogelator results in two orders of magnitude fluorescence enhancement (Φf =2.9 vs. 0.02 %), in which the inter-HBDI OHâ â â OH H-bonds play a crucial role. The aggregation-induced fluorescence enhancement of HBDI has important implications on the origin of the high fluorescence quantum efficiency of HBDI in the GFP ß-barrel and on the supramolecular strategy for a full fluorescence recovery of HBDI. These results reveal a new approach to designing rigid chromophore aggregates for high-performance optoelectronic properties.
Assuntos
Proteínas de Fluorescência Verde/química , Fluorescência , Ligação de Hidrogênio , Estrutura MolecularRESUMO
BACKGROUND: Parkinson's disease (PD) is the second most common degenerative disorder of the central nervous system that impairs motor skills and cognitive function. To date, the disease has no effective therapies. The identification of new drugs that provide benefit in arresting the decline seen in PD patients is the focus of much recent study. However, the lengthy time frame for the progression of neurodegeneration in PD increases both the time and cost of examining potential therapeutic compounds in mammalian models. An alternative is to first evaluate the efficacy of compounds in Caenorhabditis elegans models, which reduces examination time from months to days. n-Butylidenephthalide is the naturally-occurring component derived from the chloroform extract of Angelica sinensis. It has been shown to have anti-tumor and anti-inflammatory properties, but no reports have yet described the effects of n-butylidenephthalide on PD. The aim of this study was to assess the potential for n-butylidenephthalide to improve PD in C. elegans models. METHODOLOGY/PRINCIPAL FINDINGS: In the current study, we employed a pharmacological strain that expresses green fluorescent protein specifically in dopaminergic neurons (BZ555) and a transgenic strain that expresses human α-synuclein in muscle cells (OW13) to investigate the antiparkinsonian activities of n-butylidenephthalide. Our results demonstrate that in PD animal models, n-butylidenephthalide significantly attenuates dopaminergic neuron degeneration induced by 6-hydroxydopamine; reduces α-synuclein accumulation; recovers lipid content, food-sensing behavior, and dopamine levels; and prolongs life-span of 6-hydroxydopamine treatment, thus revealing its potential as a possible antiparkinsonian drug. n-Butylidenephthalide may exert its effects by blocking egl-1 expression to inhibit apoptosis pathways and by raising rpn-6 expression to enhance the activity of proteasomes. CONCLUSIONS/SIGNIFICANCE: n-Butylidenephthalide may be one of the effective neuroprotective agents for PD.
