Isolation of two cDNA clones from tomato containing two different superoxide dismutase sequences

A cDNA library was derived from the poly(A)⁺ RNA of young tomato leaves. The library was cloned in a gt11 system and screened by synthetic oligonucleotide probes having sequences that match the codes of conserved regions of amino acid sequences of Cu,Zn superoxide dismutase (SOD) proteins from a wide range of eukaryotic organisms. Two cDNAs were isolated, cloned and sequenced. One of the cDNAs, P31, had a full-size open reading frame of 456 bp with a deduced amino acid sequence having an 80% homology with the deduced amino acid sequence of the cytosolic SOD-2 cDNA of maize. The other cDNA, T10 (extended by T1), had a 651 bp open reading frame that revealed, upon computer translation, 90% homology to the amino acid sequence of mature spinach chloroplast SOD. The 5 end of the reading frame seems to code for a putative transit peptide. This work thus suggests for the first time an amino acid sequence for the transit peptide of chloroplast SOD. Northern hybridizations indicated that each of the P31 and T10 clones hybridized to a blotted poly(A)⁺ RNA species. These two species are differentially expressed in the plant organs: e.g., the species having the T10 sequence was detected in the leaves but not in roots, while the one with the P31 sequence was expressed in both leaves and roots. The cDNA clones P31 and T10 were also hybridized to Southern blots of endonuclease fragmented tomato DNA. The clones hybridized to specific fragments and no cross hybridization between the two clones was revealed under stringent hybridization conditions; the hybridization pattern indicated that, most probably, only one locus is coding for each of the two mRNA species.     

A novel site for streptomycin resistance in the “530 loop” of chloroplast 16S ribosomal RNA

The chloroplast gene for 16S rRNA was cloned from two maternally inherited streptomycin-resistant mutants ofNicotiana differing in degree of resistance at the whole plant and isolated chloroplast level. A single-nucleotide change in the 16S rRNA gene was detected for each mutant: a C to T transition at nucleotide 860 (Escherichia coli coordinate C₉₁₂) which is an often mutated site, and a novel transition of C to T at nucleotide 472 (E. coli coordinate C₅₂₅). The novel mutation is located in the phylogenetically conserved 530 loop.     

Differentiations of Chitin Content and Surface Morphologies of Chitins Extracted from Male and Female Grasshopper Species

In this study, we used Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) to investigate chitin structure isolated from both sexes of four grasshopper species. FT-IR, EA, XRD, and TGA showed that the chitin was in the alpha form. With respect to gender, two main differences were observed. First, we observed that the quantity of chitin was greater in males than in females and the dry weight of chitin between species ranged from 4.71% to 11.84%. Second, using SEM, we observed that the male chitin surface structure contained 25 – 90nm wide nanofibers and 90 – 250 nm nanopores, while no pores or nanofibers were observed in the chitin surface structure of the majority of females (nanofibers were observed only in M. desertus females). In contrast, the elemental analysis, thermal properties, and crystalline index values for chitin were similar in males and females. Also, we carried out enzymatic digestion of the isolated chitins using commercial chitinase from Streptomyces griseus. We observed that there were no big differences in digestion rate of the chitins from both sexes and commercial chitin. The digestion rates were for grasshoppers’ chitins; 88.45–95.48% and for commercial chitin; 94.95%.     

Advances and challenges in cancer treatment and nutraceutical prevention: the possible role of dietary phenols in BRCA regulation

Phytochemistry Reviews - Over the years, the attention towards the role of phytochemicals in dietary natural products in reducing the risk of developing cancer is rising. Cancer is the second...     

Chitosan film containing fucoidan as a wound dressing for dermal burn healing: Preparation and in vitro/in vivo evaluation

The aim of this study was to develop chitosan film containing fucoidan and to investigate its suitability for the treatment of dermal burns on rabbits. Porous films, thickness between 29.7 and 269.0 μm, were obtained by the solvent dropping method. Water vapor permeability (3.3–16.6/0.1 g), the swelling (0.67–1.77 g/g), tensile strength (7.1–45.8 N), and bioadhesion (0.076–1.771 mJ/cm²) of the films were determined. The thinnest films were obtained with the lowest chitosan concentration (P<.05). The water absorption capacity of the films sharply increased with the freeze-drying technique. The film having the thickness of 29.7 μm showed the highest amount of moisture permeability (16.6 g/0.1 g). Higher chitosan concentration significantly increased tensile strength of the films (P<.05). Using higher concentration of lactic acid made films more elastic and applicable, and these films were selected for in vivo studies. Seven adult male New Zealand white rabbits were used for the evaluation of the films on superficial dermal burns. Biopsy samples were taken at 7, 14, and 21 days after wounding, and each wound site was examined macroscopically and histopathologically. After 7 days treatment, fibroplasia and scar were observed on wounds treated with fucoidan-chitosan film. The best regenerated dermal papillary formation, best reepithelization, and the fastest closure of wounds were found in the fucoidan-chitosan film treatment group after 14 days compared with other treatment and control groups. It can be concluded that fucoidan-chitosan films might be a potential treatment system for dermal burns and that changing formulation variables can modulate the characterizations of the films. Published: May 24, 2007     

Tailoring the size distribution of ultrasound contrast agents: possible method for improving sensitivity in molecular imaging

Encapsulated microbubble contrast agents incorporating an adhesion ligand in the microbubble shell are used for molecular imaging with ultrasound. Currently available microbubble agents are produced with techniques that result in a large size variance. Detection of these contrast agents depends on properties related to the microbubble diameter such as resonant frequency, and current ultrasound imaging systems have bandwidth limits that reduce their sensitivity to a polydisperse contrast agent population. For ultrasonic molecular imaging, in which only a limited number of targeted contrast agents may be retained at the site of pathology, it is important to optimize the sensitivity of the imaging system to the entire population of contrast agent. This article presents contrast agents with a narrow size distribution that are targeted for molecular imaging applications. The production of a functionalized, lipid-encapsulated, microbubble contrast agent with a monodisperse population is demonstrated, and we evaluate parameters that influence the size distribution and demonstrate initial acoustic testing.