We report tumor targeting nanoparticles for optical/MR dual imaging based on self-assembled glycol chitosan to be a potential multimodal imaging probe. To develop an optical/MR dual imaging probe, biocompatible and water-soluble glycol chitosan (M(w) = 50 kDa) were chemically modified with 5beta-cholanic acid (CA), resulting in amphiphilic glycol chitosan-5beta-cholanic acid conjugates (GC-CA). For optical imaging near-infrared fluorescence (NIRF) dye, Cy5.5, was conjugated to GC-CA resulting in Cy5-labeled GC-CA conjugates (Cy5.5-GC-CA). Moreover, in order to chelate gadolinium (Gd(III)) in the Cy5.5-GC-CA conjugates, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was directly conjugated in Cy5.5-GC-CA. Finally, the excess GdCl(3) was added to DOTA modified Cy5.5-GC-CA conjugates in distilled water (pH 5.5). The freshly prepared Gd(III) encapsulated Cy5.5-GC-CA conjugates were spontaneously self-assembled into stable Cy5.5 labeled and Gd(III) encapsulated chitosan nanoparticles (Cy5.5-CNP-Gd(III)). The Cy5.5-CNP-Gd(III) was spherical in shape and approximately 350 nm in size. From the cellular experiment, it was demonstrated that Cy5.5-CNP-Gd(III) were efficiently taken up and distributed in cytoplasm (NIRF filter; red). When the Cy5.5-GC-Gd(III) were systemically administrated into the tail vein of tumor-bearing mice, large amounts of nanoparticles were successfully localized within the tumor, which was confirmed by noninvasive near-infrared fluorescence and MR imaging system simultaneously. These results revealed that the dual-modal imaging probe of Cy5.5-CNP-Gd(III) has the potential to be used as an optical/MR dual imaging agent for cancer treatment.
Nomenclature Wagner et al. (1999) for all native Hawaiian species USDA ARS-GRIN (www.ars-grin.gov/ npgs/) for M. maximus Abstract Questions: How does a highly degraded Hawaiian tropical dry lowland ecosystem dominated by the non-native invasive Megathyrsus maximus (guinea grass) respond to different restoration treatments (three native species outplanting treatments; four native broadcast seed treatments)? What effect do restoration treatments have on invasive and native species groundcover, biomass and physiological activity, and volumetric soil water content?Location: Waianae Kai Forest Reserve, Island of Oahu, Hawaii, USA. Methods:The invasive grass M. maximus was suppressed by initial mowing and pre-and post-planting herbicide applications. Native species were added in three outplant and four broadcast seed treatments in a complete randomized block design. Native species and M. maximus growth and ecophysiology, and volumetric soil water content were quantified for 8 mo following treatment establishment.Results: Native species outplant survival ranged from 38% to 67%. Cover of M. maximus was significantly reduced in all outplant treatments compared with control and treated control (mowing and herbicide without native species additions), but did not differ across outplant treatments. Of the native species, Dodonaea viscosa biomass was higher than Cordia subcordata, while other native species did not differ. Maximum photosynthetic rates (A max ) did not differ across species in July. However, in August (drier period), M. maximus exhibited lower A max than all native species except T. populnea, indicating adaptive dormancy during drought. Broadcast seeding with native species was not an effective restoration treatment, as field germination ranged from 0.5% to 2.3%.Conclusions: Ecological restoration of highly invaded Hawaiian tropical dry lowland ecosystems can be mediated through aggressive invasive species suppression and native species outplanting. Recommendations for restoration include initial removal of invasive grasses, adaptive suppression of grasses postoutplanting, and utilization of diverse native species assemblages that are ecophysiologically adapted to local conditions and competitive with M. maximus.
Hawai'i has served as a model system for studies of nutrient cycling and conservation biology. The islands may also become a laboratory for exploring new approaches to forest restoration because of a common history of degradation and the growing number of restoration projects undertaken. Approximately half of the native ecosystems of Hawai'i have been converted to non-native conditions. Many restoration projects have focused on intensively managed out plantings of native plants with emphasis on threatened and endangered species. While these projects have been effective in stabilizing plant populations, this model is often prohibitively expensive for restoration at the scale needed to protect watersheds and provide habitat for rare bird species. Here we suggest ways of rethinking ecological restoration that are applicable across the tropics, particularly on islands and fire-prone grasslands. First, we suggest making use of nonnative, non-invasive species to help reclaim degraded or invaded sites or as long-term components of planned restoration outcomes. Second, we suggest incorporating remote sensing techniques to refine where restoration is carried out. Finally, we suggest borrowing technologies in plant production, weed control, and site preparation from industrial forestry to lower restoration costs. These suggestions would result in ecosystems that differ from native reference systems in some cases but which could be applied to much larger areas than most current restoration efforts while providing important ecosystem services. We also stress that community involvement is key to successful restoration, as a major goal of almost all restoration projects is to re-connect the community with the forest.
Canopy nodulation of Acacia koa (koa) is the result of a unique symbiosis between the host adventitious root system and the bradyrhizobia residing in “pockets” within the canopy of koa. These canopy pockets contain trapped organic soils that are mainly derived from decomposing heartwood and phyllode litter of the host tree. These canopy soils have significantly higher levels of exchangeable cations, total nitrogen content, and significantly lower aluminum levels than the terrestrial soils. Canopy Bradyrhizobium isolates from separate koa trees of different locations do not share matching box‐polymerase chain reaction (PCR) fingerprints, showing that there is no single type that is specific to canopy nodulation. Within the canopy pocket of a single tree, however, we observed a homogenous Bradyrhizobium population that was distinct from the proximal terrestrial population. Canopy nodulation has only been observed on mature koa trees and may function in maintaining symbiosis under stresses occurring within the rhizosphere of the terrestrial environment.
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