1,007 research outputs found

    1 H-cyclopropa[b]naphthalene: A novel ethylene antagonist for extending storage life and maintaining quality of climacteric and suppressed climacteric plums

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    Ethylene is a key trigger that governs the rate of fruit ripening, storability, and postharvest quality of fresh fruit. Efficient inhibition of ethylene action is essential to slow down the postharvest ripening processes, extend storage life and maintain optimum fruit quality during storage. Ethylene antagonist compounds with the likelihood of application as liquid formulation would facilitate managing ethylene broadly as both preharvest and/or postharvest treatments. This study examined the effects of different aqueous formulations of 1 H-cyclopropa[b]naphthalene (NC) as an ethylene antagonist in the cold stored (1 °C) Japanese plums ‘Angeleno’ (suppressed-climacteric) and ‘Tegan Blue’, which exhibit climacteric peaks, respectively. NC was applied as a 2 M spray solution prepared using only distilled water (NCA), 5% ethanol (NCE), 0.02% Tween 20 (NCT), 5% -cyclodextrin (NCD) or a 1 M fumigant for 18 h at ambient conditions (20 ± 1 °C). Regardless of formulation, NC retarded ethylene production in both the suppressed-climacteric and climactic cultivars. The capacity of NC to suppress ethylene production was relatively higher in ‘Angeleno’ than in ‘Tegan Blue’. Levels of bioactive compounds such as total phenols, total anthocyanins and total antioxidant capacity in fruit treated with NC were at par with the control. NC fumigation was the most effective treatment in suppressing ethylene production and maintaining fruit quality followed by NCE, NCT, NCD and NCA in both plum cultivars. Amongst the NC spray solutions, the ones with ethanol or Tween 20 as adjuvants outperformed other solutions. Ethylene production positively correlated with weight loss, SSC, SSC: TA and concentrations of individual sugars, but was negatively correlated with firmness, titratable acidity (TA) and individual organic acids in both cultivars. The results also support the notion that ethylene has a role in the synthesis of phenolic compounds and anthocyanin depending on the sugar substrates present in the phenylpropanoid and flavonoid pathways

    Postharvest fruit quality of apple influenced by ethylene antagonist fumigation and ozonized cold storage

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    The effects of two new ethylene antagonists namely 1H-cyclopropabenzene (BC) and 1H-cyclopropa[b]naphthalene (NC), as well as 1-methylcyclopropene (1-MCP) on ethylene production and fruit quality of Cripps Pink and Granny Smith apple in ozonized cold storage, were investigated. When compared to control, Cripps Pink fruit fumigated with BC and NC exhibited significantly lowest ethylene production and respiration, whilst the Granny Smith fruit treated with 1-MCP exhibited lowest ethylene production followed by NC and BC treatments. Application of ozone in cold storage maintained higher levels of sugars but elevated ethylene production in both the apple cultivars. No significant interaction was recorded between ethylene antagonists and ozone application in cold storage on the ethylene production, respiration and other fruit quality parameters. In conclusion, results suggest that BC and NC are potential ethylene antagonists in Cripps Pink and Granny Smith apples during the cold storage

    Postharvest fruit quality of apple influenced by ethylene antagonist fumigation and ozonized cold storage

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    The effects of two new ethylene antagonists namely 1H-cyclopropabenzene (BC) and 1H-cyclopropa[b]naphthalene (NC), as well as 1-methylcyclopropene (1-MCP) on ethylene production and fruit quality of Cripps Pink and Granny Smith apple in ozonized cold storage, were investigated. When compared to control, Cripps Pink fruit fumigated with BC and NC exhibited significantly lowest ethylene production and respiration, whilst the Granny Smith fruit treated with 1-MCP exhibited lowest ethylene production followed by NC and BC treatments. Application of ozone in cold storage maintained higher levels of sugars but elevated ethylene production in both the apple cultivars. No significant interaction was recorded between ethylene antagonists and ozone application in cold storage on the ethylene production, respiration and other fruit quality parameters. In conclusion, results suggest that BC and NC are potential ethylene antagonists in Cripps Pink and Granny Smith apples during the cold storage

    Natural Nutrient Sources in the Cache River Watershed, Arkansas

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    The growth of the hypoxic ‘dead zone’ in the Gulf of Mexico in recent years has placed increased focus on potential sources of nutrient pollution, with most of the focus being placed on watersheds where practices, including fertilizer application and land alterations combine to increase non-point source runoff. In this study, nutrient concentrations in surface waters of altered and unaltered areas of the Cache River Watershed, Arkansas, were compared to determine if agricultural land usage was responsible for the majority of nutrient inputs. Results suggest that for dissolved nitrites and orthophosphates, agricultural (altered) sites contribute significantly more than relatively unaltered sites but that for dissolved nitrates, unaltered sites have a large contribution to overall nitrate concentrations, particularly in late summer and fall months

    Formation of a Unique Cluster of G-Quadruplex Structures in the HIV-1 nef Coding Region: Implications for Antiviral Activity

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    G-quadruplexes are tetraplex structures of nucleic acids that can form in G-rich sequences. Their presence and functional role have been established in telomeres, oncogene promoters and coding regions of the human chromosome. In particular, they have been proposed to be directly involved in gene regulation at the level of transcription. Because the HIV-1 Nef protein is a fundamental factor for efficient viral replication, infectivity and pathogenesis in vitro and in vivo, we investigated G-quadruplex formation in the HIV-1 nef gene to assess the potential for viral inhibition through G-quadruplex stabilization. A comprehensive computational analysis of the nef coding region of available strains showed the presence of three conserved sequences that were uniquely clustered. Biophysical testing proved that G-quadruplex conformations were efficiently stabilized or induced by G-quadruplex ligands in all three sequences. Upon incubation with a G-quadruplex ligand, Nef expression was reduced in a reporter gene assay and Nef-dependent enhancement of HIV-1 infectivity was significantly repressed in an antiviral assay. These data constitute the first evidence of the possibility to regulate HIV-1 gene expression and infectivity through G-quadruplex targeting and therefore open a new avenue for viral treatment. © 2013 Perrone et al

    Structural network heterogeneities and network dynamics: a possible dynamical mechanism for hippocampal memory reactivation

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    The hippocampus has the capacity for reactivating recently acquired memories [1-3] and it is hypothesized that one of the functions of sleep reactivation is the facilitation of consolidation of novel memory traces [4-11]. The dynamic and network processes underlying such a reactivation remain, however, unknown. We show that such a reactivation characterized by local, self-sustained activity of a network region may be an inherent property of the recurrent excitatory-inhibitory network with a heterogeneous structure. The entry into the reactivation phase is mediated through a physiologically feasible regulation of global excitability and external input sources, while the reactivated component of the network is formed through induced network heterogeneities during learning. We show that structural changes needed for robust reactivation of a given network region are well within known physiological parameters [12,13].Comment: 16 pages, 5 figure

    Increasing compliance with wearing a medical device in children with autism

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    Health professionals often recommend the use of medical devices to assess the health, monitor the well-being, or improve the quality of life of their patients. Children with autism may present challenges in these situations as their sensory peculiarities may increase refusals to wear such devices. To address this issue, we systematically replicated prior research by examining the effects of differential reinforcement of other behavior (DRO) to increase compliance with wearing a heart rate monitor in 2 children with autism. The intervention increased compliance to 100% for both participants when an edible reinforcer was delivered every 90 s. The results indicate that DRO does not require the implementation of extinction to increase compliance with wearing a medical device. More research is needed to examine whether the reinforcement schedule can be further thinned

    Gathering in the City: An Annotated Bibliography and Review of the Literature About Human-Plant Interactions in Urban Ecosystems

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    The past decade has seen resurgence in interest in gathering wild plants and fungi in cities. In addition to gathering by individuals, dozens of groups have emerged in U.S., Canadian, and European cities to facilitate access to nontimber forest products (NTFPs), particularly fruits and nuts, in public and private spaces. Recent efforts within cities to encourage public orchards and food forests, and to incorporate more fruit and nut trees into street tree planting programs indicate a growing recognition among planners that gathering is an important urban activity. Yet the academic literature has little to say about urban gathering practices or the people who engage in them. This annotated bibliography and literature review is a step toward filling the gap in knowledge about the socioecological roles of NTFPs in urban ecosystems in the United States. Our objectives are to demonstrate that gathering—the collecting of food and raw materials—is a type of human-plant interaction that warrants greater attention in urban green space management, and to provide an overview of the literature on human-plant interactions—including gathering—in urban environments. Our review found that very few studies of urban gathering have been done. Consequently, we included gathering field guides, Web sites, and articles from the popular media in our search. These sources, together with the small number of scientific studies of urban gathering, indicated that people derive numerous benefits from gathering plants and fungi in U.S. cities. Gathering provides useful products, encourages physical activity, offers opportunities to connect with and learn about nature, helps strengthen social ties and cultural identities, and, in some contexts, can serve as a strategic tool for ecological restoration. These benefits parallel those identified in environmental psychology and cultural ecology studies of the effects of gardening and being in nature. The literature on human-plant interactions also emphasizes that humans need to be treated as endogenous factors in dynamic, socially and spatially heterogeneous urban ecosystems. Spatially explicit analyses of human-plant interactions show that the distribution of wealth and power within societies affects the composition, species distribution, and structure of urban ecologies. Our review also indicates that tensions exist between NTFP gatherers and land managers, as well as between gatherers and other citizens over gathering, particularly in public spaces. This tension likely is related to perceptions about the impact these practices have on cherished species and spaces. We conclude that gathering is an important urban activity and deserves a greater role in urban management given its social and potential ecological benefits. Research on urban gathering will require sensitivity to existing power imbalances and the use of theoretical frameworks and methodologies that assume humans are integral and not always negative components of ecosystems

    Downregulation of Mcl-1 has anti-inflammatory pro-resolution effects and enhances bacterial clearance from the lung

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    Phagocytes not only coordinate acute inflammation and host defense at mucosal sites, but also contribute to tissue damage. Respiratory infection causes a globally significant disease burden and frequently progresses to acute respiratory distress syndrome, a devastating inflammatory condition characterized by neutrophil recruitment and accumulation of protein-rich edema fluid causing impaired lung function. We hypothesized that targeting the intracellular protein myeloid cell leukemia 1 (Mcl-1) by a cyclin-dependent kinase inhibitor (AT7519) or a flavone (wogonin) would accelerate neutrophil apoptosis and resolution of established inflammation, but without detriment to bacterial clearance. Mcl-1 loss induced human neutrophil apoptosis, but did not induce macrophage apoptosis nor impair phagocytosis of apoptotic neutrophils. Neutrophil-dominant inflammation was modelled in mice by either endotoxin or bacteria (Escherichia coli). Downregulating inflammatory cell Mcl-1 had anti-inflammatory, pro-resolution effects, shortening the resolution interval (R(i)) from 19 to 7 h and improved organ dysfunction with enhanced alveolar–capillary barrier integrity. Conversely, attenuating drug-induced Mcl-1 downregulation inhibited neutrophil apoptosis and delayed resolution of endotoxin-mediated lung inflammation. Importantly, manipulating lung inflammatory cell Mcl-1 also accelerated resolution of bacterial infection (R(i); 50 to 16 h) concurrent with enhanced bacterial clearance. Therefore, manipulating inflammatory cell Mcl-1 accelerates inflammation resolution without detriment to host defense against bacteria, and represents a target for treating infection-associated inflammation
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