Search

Approximately 30% of the world's land area is acidic soil (pH < 5.5), and aluminum (Al) toxicity and phosphorus (P) deficiency are two main constraints of plant growth in acidic soil. However, direct application of P fertilizer to acidic soil can form insoluble Al–P precipitates, thus reducing P availability. We used a split-root technique to experimentally investigate whether Eucalyptus seedlings can translocate P from root halves with no Al stress to root halves experiencing Al stress, thus ameliorating the Al toxicity of the latter. The results revealed that P application led to fixation of Al in the form of an Al–P precipitate in sand, thus relieving Al toxicity. In addition, the application of P increased the nutritive P supply and alleviated P deficiency within the plant. In Eucalyptus seedlings, increased P application to the root half without Al3+ exposure alleviated Al toxicity in the other root half. The extent of resistance to Al stress depended on the genotype of the Eucalyptus seedlings. Based on our findings, P can be applied to areas not only through roots, but also by other methods, such as leaf fertilization or application of nutrient solutions to the trunk, preferably avoiding the formation of Al–P precipitates in the soil. [ABSTRACT FROM AUTHOR]

The key structural requirement for the antitumor activity of 10-hydroxycamptothecin (HCPT) is the intact lactone moiety which is always instability and suffered from pH-dependent hydrolysis. The aim of this study was to evaluate the protection effects of liposomal encapsulation on the labile lactone ring. Mono-modal dispersed quasi-spherical liposomes with mean diameter of 145 nm and high drug entrapment efficiency of 90% were obtained under optimal conditions. The in vitro hydrolysis kinetics behaviors of lactone were studied in varied pH buffers. Compared to that of free HCPT in solution formulation, both the hydrolysis half-life and observed equilibrium constant of liposomal HCPT were increased significantly along with the decreased apparent hydrolysis rate constant. The plasma pharmacokinetics was studied by assessing the lactone stability versus time profiles in vivo following intravenous administration of free and liposomal HCPT. The liposomal encapsulation led to a twofold increase in the AUC values and significant decrease in the plasma clearance of lactone ( P < 0.05). There was a good correlation between in vitro and in vivo stability of HCPT-lactone. These results suggested a potential application of the novel liposome formulation for the stable delivery system of HCPT. [ABSTRACT FROM AUTHOR]

Despite its strong anti-tumor activity against human cancers, paclitaxel (Taxol®) suffers limited clinical applications due to the low aqueous solubility and lack of appropriate delivery vehicles. In an attempt to develop an alternative formulation of paclitaxel suitable for parenteral administration, paclitaxel-loaded lipid nanospheres were constructed as colloidal carrier system for controlled drug delivery. Alpha-tocopheryl succinate ( α-TOS), a semi-synthetic vitamin E analog, was employed as a new physiological acceptable lipid material to prepare nanoparticulates. A novel bottom-up process was performed by a modified spontaneous emulsification solvent-diffusion method, which is suitable for large industrial scale production. The influence of key parameters such as temperature and surfactant concentration on the size and uniformity of the distribution of nanospheres were investigated. Spherical particles with ∼ 100 nm of mean diameter and 90% of drug entrapment efficiency were obtained under optimal conditions. Physicochemical characterization of the particles reveals a molecular dispersion of paclitaxel in the lipidic matrix. The in vitro release behavior of paclitaxel from the developed nanospheres was characterized by an initial fast release, followed by a sustained release up to 72 h. The release mechanism suggests that paclitaxel release from the vehicles was dual controlled by both the diffusion of drug and corrosion of lipid matrix. These results demonstrate the principle suitability of α-TOS-based lipid nanospheres as a potential delivery system for paclitaxel delivery. [ABSTRACT FROM AUTHOR]

The rational design of direct Z-scheme heterostructural photocatalysts using solar energy is promising for energy conversion and environmental remediation, which depends on the precise regulation of redox active sites, rapid spatial separation and transport of photoexcited charge and a broad visible light response. The Bi2WO6 materials have been paid more and more attention because of their unique photochemical properties. In this study, S2− doped Bi2WO6-x coupled with twin crystal ZnIn2S4 nanosheets (Sov−BWO/T−ZIS) were prepared as an efficient photocatalyst by a simple hydrothermal method for the removal of tetracycline hydrochloride (TCH). Multiple methods (XRD, TEM, XPS, EPR, UV vis DRS, PL etc.) were employed to systematically investigate the morphology, structure, composition and photochemical properties of the as-prepared samples. The XRD spectrum indicated that the S2− ions were successfully doped into the Sov−BWO component. XPS spectra and photoelectrochemical analysis proved that S2− served as electronic bridge and promoted captured electrons of surface oxygen vacancies transfer to the valence band of T−ZIS. Through both experimental and in situ electron paramagnetic resonance (in situ EPR) characterizations, a defined direct Z-scheme heterojunction in S-BWO/T−ZIS was confirmed. The improved photocatalytic capability of S-BWO/T−ZIS results ascribed that broadened wavelength range of light absorption, rapid separation and interfacial transport of photoexcited charge, precisely regulated redox centers by optimizing the interfacial transport mode. Particularly, the Sov−50BWO/T−ZIS Z-scheme heterojunction exhibited the highest photodegradation rate was 95% under visible light irradiation. Moreover, this heterojunction exhibited a robust adsorption and degradation capacity, providing a promising photocatalyst for an organic pollutant synergistic removal strategy. [ABSTRACT FROM AUTHOR]

Ramie (Boehmeria nivea L.) is an important bast fiber crop. To study genetic background of this species, we isolated and characterized microsatellite markers of ramie. A genomic library containing inserts of rapid amplification of polymorphic DNA (RAPD) fragments was constructed, and screened by PCR amplification using anchored simple sequence repeats as primers. A total of 26 clones were identified as positives, and 13 microsatellite loci were found alter sequencing. The polymorphism of these 13 microsatellite loci was examined and the utility of simple sequence repeats (SSR) and inter-SSR (ISSR) marker systems for genetic characterization compared using 19 selected ramie cultivars. Both approaches successfully discriminated the 19 cultivars which differed in the amount of polymorphism detected. The level of polymorphism detected by SSR was 95.0 %, higher than that by ISSR (72.3 %), but the average polymorphism information content (PlC) of ISSR (0.651) was higher than that of SSR (0.441). The higher PlC value of ISSR suggests that ISSR is more efficient for fingerprinting ramie cultivars than SSR markers. However, because the SSR loci are codominant, they are more suitable for determining the homozygosity levels of ramie, constructing linkage map, quantitative trait loci study of complex traits and marker-assisted selection. [ABSTRACT FROM AUTHOR]

Nav1.8 is a tetrodotoxin-resistant voltage-gated sodium channel selectively expressed in primary sensory neurons. Peripheral inflammation and nerve injury induce Nav1.8 accumulation in peripheral nerves. However, the mechanisms and related significance of channel accumulation in nerves remains unclear. Here we report that KIF5B promotes the forward transport of Nav1.8 to the plasma membrane and axons in dorsal root ganglion (DRG) neurons of the rat. In peripheral inflammation induced through the intraplantar injection of complete Freund's adjuvant, increased KIF5 and Nav1.8 accumulation were observed in the sciatic nerve. The knock-down of KIF5B, a highly expressed member of the KIF5 family in DRGs, reduced the current density of Nav1.8 in both cultured DRG neurons and ND7-23 cells. Overexpression of KIF5B in ND7-23 cells increased the current density and surface expression of Nav1.8, which were abolished through brefeldin A treatment, whereas the increases were lost in KIF5B mutants defective in ATP hydrolysis or cargo binding. Overexpression of KIF5B also decreased the proteasome-associated degradation of Nav1.8. In addition, coimmunoprecipitation experiments showed interactions between the N terminus of Nav1.8 and the 511-620 aa sequence in the stalk domain of KIF5B. Furthermore, KIF5B increased Nav1.8 accumulation, Nav1.8 current, and neuronal excitability detected in the axons of cultured DRG neurons, which were completely abolished by the disruption of interactions between KIF5B and the N terminus of Nav1.8. Therefore, our results reveal that KIF5B is required for the forward transport and axonal function of Nav1.8, suggesting a mechanism for axonal accumulation of Nav1.8 in inflammatory pain.