Production of tocotrienols in seeds of cotton (Gossypium hirsutum L.) enhances oxidative stability and offers nutraceutical potential.

Upland cotton (Gossypium hirsutum L.) is an economically important multi-purpose crop cultivated globally for fibre, seed oil and protein. Cottonseed oil also is naturally rich in vitamin E components (collectively known as tocochromanols), with α- and γ-tocopherols comprising nearly all of the vitamin E components. By contrast, cottonseeds have little or no tocotrienols, tocochromanols with a wide range of health benefits. Here, we generated transgenic cotton lines expressing the barley (Hordeum vulgare) homogentisate geranylgeranyl transferase coding sequence under the control of the Brassica napus seed-specific promoter, napin. Transgenic cottonseeds had ~twofold to threefold increases in the accumulation of total vitamin E (tocopherols + tocotrienols), with more than 60% γ-tocotrienol. Matrix assisted laser desorption ionization-mass spectrometry imaging showed that γ-tocotrienol was localized throughout the transgenic embryos. In contrast, the native tocopherols were distributed unequally in both transgenic and non-transgenic embryos. α- Tocopherol was restricted mostly to cotyledon tissues and γ-tocopherol was more enriched in the embryonic axis tissues. Production of tocotrienols in cotton embryos had no negative impact on plant performance or yield of other important seed constituents including fibre, oil and protein. Advanced generations of two transgenic events were field grown, and extracts of transgenic seeds showed increased antioxidant activity relative to extracts from non-transgenic seeds. Furthermore, refined cottonseed oil from the two transgenic events showed 30% improvement in oxidative stability relative to the non-transgenic cottonseed oil. Taken together, these materials may provide new opportunities for cottonseed co-products with enhanced vitamin E profile for improved shelf life and nutrition.

Identification and classification of respiratory syncytial virus (RSV) strains by surface-enhanced Raman spectroscopy and multivariate statistical techniques.

There is a critical need for a rapid and sensitive means of detecting viruses. Recent reports from our laboratory have shown that surface-enhanced Raman spectroscopy (SERS) can meet these needs. In this study, SERS was used to obtain the Raman spectra of respiratory syncytial virus (RSV) strains A/Long, B1, and A2. SERS-active substrates composed of silver nanorods were fabricated using an oblique angle vapor deposition method. The SERS spectra obtained for each virus were shown to possess a high degree of reproducibility. Based on their intrinsic SERS spectra, the four virus strains were readily detected and classified using the multivariate statistical methods principal component analysis (PCA) and hierarchical cluster analysis (HCA). The chemometric results show that PCA is able to separate the three virus strains unambiguously, whereas the HCA method was able to readily distinguish an A2 strain-related G gene mutant virus (DeltaG) from the A2 strain. The results described here demonstrate that SERS, in combination with multivariate statistical methods, can be utilized as a highly sensitive and rapid viral identification and classification method.

Aligned silver nanorod arrays as substrates for surface-enhanced infrared absorption spectroscopy.

Preferentially aligned silver nanorod arrays prepared by oblique angle vapor deposition were evaluated as substrates for surface-enhanced infrared absorption (SEIRA) spectroscopy. These nanorod arrays have an irregular surface lattice and are composed of tilted, cylindrically shaped nanorods that have an average length of 868 nm +/- 95 nm and an average diameter of 99 nm +/- 29 nm. The overall enhancement factor for chemisorbed organic films of para-nitrobenzoic acid (PNBA) deposited onto the Ag nanorod arrays analyzed by external reflection SEIRA was calculated to be 31 +/- 9 compared to infrared reflection-absorption spectroscopy (IRRAS) obtained from a 500 nm Ag film substrate. This enhancement is attributed to the unique optical properties of the nanorod arrays as well as the increased surface area provided by the nanorod substrate. SEIRA reflection-absorbance intensity was observed with both p- and s-polarized incident radiation with angles of incidence ranging from 25 degrees to 80 degrees . The largest intensity was achieved with p-polarization and incident angles larger than 75 degrees . Polarization-dependent ultraviolet/visible/near-infrared (UV/Vis/NIR) spectra of the nanorod arrays demonstrate that the red-shifted surface plasmon peaks of the elongated nanorods may be partially responsible for the observed SEIRA response. The SEIRA detection limit for the Ag nanorod arrays was estimated to be 0.08 ng/cm(2). Surface-enhanced Raman scattering (SERS) and SEIRA analysis of chemisorbed PNBA utilizing the same nanorod substrate is demonstrated.