Hydrogen sulphide alleviates cadmium stress in Trigonella foenum-graecum by modulating antioxidant enzymes and polyamine content

Cadmium (Cd) toxicity reduces growth and yield of crops grown in metal-polluted sites. Research was conducted to estimate the potential of hydrogen sulphide (H₂ S) to mitigate toxicity caused by Cd in fenugreek seedlings (Trigonella foenum-graecum L.). Different concentrations of CdCl₂ (Cd1-1 mM, Cd2-1.5 mM, Cd3-2mM) and H₂ S (HS1-100 µM, HS2-150 µM, HS3-200 µM) were assessed. Seeds of fenugreek were primed with sodium hydrosulphide (NaHS), as H₂ S donor. Seedlings growing in Cd-spiked media treated with H₂ S were harvested after 2 weeks. Cd stress affected growth of fenugreek seedlings. Cd toxicity decreased leaf relative water content (LRWC), intercellular CO₂ concentration, net photosynthesis, stomatal conductance and transpiration. However, application of H₂ S significantly improved seedling morphological attributes by increasing the activity of antioxidant enzymes, i.e. APX, CAT and SOD, in Cd-contaminated soil. H₂ S treatment also regulated phenolic and flavonoid content. H₂ S-induced biosynthesis of spermidine (Spd) and putrescine (Put) could account for the enhancement of growth and physiological performance of fenugreek seedlings under Cd stress. H₂ S treatment also reduced H₂ O₂ production (38%) and electrolyte leakage (EL, 51%) in seedlings grown in different concentrations of Cd. It is recommended to evaluate the efficacy of H₂ S in alleviating Cd toxicity in other crop plants.

Single-step generation of fluorophore-encapsulated gold nanoparticle core-shell materials

We report a simple route to produce fluorophore-encapsulated gold nanoparticles (AuNPs) in a single step under aqueous conditions using the fluorophore 1-pyrenemethylamine (PMA). Different amounts of PMA were used and the resulting core-shell gold nanoparticles were analyzed using UV-visible absorption spectroscopy, fluorescence spectroscopy, and transmission and scanning electron microscopy. Electron microscopy analysis shows nanoparticles consisting of a gold nanoparticle core which is encapsulated with a lower contrast shell. In the UV-visible spectra, we observed a significant red shift (37 nm) of the localized surface plasmon resonance (LSPR) absorption maximum (lambda(max)) compared to citrate-stabilized AuNPs of a similar size. We attribute the prominent LSPR wavelength shift for PMA-AuNP conjugates to the increase in the local dielectric environment near the gold nanoparticles due to the shell formation. This simple, aqueous-based synthesis is a new approach to the production of fluorophore-encapsulated AuNPs that could be applicable in biological sensing systems and photonic device fabrication.

Viability of the acetabular bone bed at revision surgery following cemented primary arthroplasty

Loosening of total hip replacements is often associated with severe loss of periprosthetic bone. The notion exists that the remaining bone is sclerotic, avascular, and displays little osteogenic activity, and that it therefore potentially compromises the revitalization of bone grafts used to restore bony defects. To verify this opinion we studied the bone characteristics in acetabular bone biopsies taken at primary total hip arthroplasty (PTH) and revision total hip arthroplasty (RTH) for a cemented PTH. In 6 PTH patients and in 10 RTH patients, acetabular bone biopsies were taken from the roof, the center, and the lower rim of each acetabulum. Specimens were evaluated by light microscopy and histomorphometrically measured for specimen size, bone area, perimeter, active osteoid perimeter, number of vessels, and osteoclasts. The vascularity and vitality appeared to be comparable in the RTH and PTH bone biopsies. However, the trabecular organization of the RTH bone differed from that of the PTH biopsies. In the PTH biopsies, the trabeculae were running perpendicular to the subchondral bone layer, whereas in the RTH biopsies the layers of bone were oriented parallel to the implant surface. There was abundant remodeling activity in the RTH bone, with large quantities of active osteoid and osteoclasts. These histologic parameters differed, but not statistically significant, from the PTH biopsies. In conclusion, we found that at revision, the acetabular bone was viable with sufficient vascularity and remodeling activity to provide an acceptable recipient host bone bed for revision surgery combined with bone grafting.