Application of near-infrared spectroscopy in quality control and determination of adulteration of African essential oils

An evaluation has been made of the potential of near-infrared (NIR) technologies in the assessment of essential oil components and in the identification of individual essential oils. The results showed that cross-validation models are able to predict accurately almost all of the components of essential oils. In different cinnamon (Cinnamomum zeylanicum) and clove (Syzygium aromaticum) essential oils, which showed a similar composition, 23 components (representing 97.8-99.9% of the oil) were accurately predicted, as well as 20 components (93.0-99.1%) in Cinnamomum camphora (ravintsara), 32 components (92.3-98.1%) in Ravensara aromatica (ravensara), and 26 components (96.6-98.4%) in Lippia multiflora. For almost all of the components, the modelled and reference values obtained by GC-FID were highly correlated (r2 > or = 0.985) and exhibited a low variance (less than 5%). The model was also able to discriminate between the ravintsara and ravensara essential oils. It was shown that two commercial oils labelled as R. aromatica were actually ravintsara (C. camphora), revealing the misidentification of these essential oils in the marketplace. The study demonstrates the application of NIR technology as a quality control tool for the rapid identification of individual essential oils, for product authentication, and for the detection of adulteration.     

Reverse Engineering the Neuroblastoma Regulatory Network Uncovers MAX as One of the Master Regulators of Tumor Progression

Neuroblastoma is the most common extracranial tumor and a major cause of infant cancer mortality worldwide. Despite its importance, little is known about its molecular mechanisms. A striking feature of this tumor is its clinical heterogeneity. Possible outcomes range from aggressive invasion to other tissues, causing patient death, to spontaneous disease regression or differentiation into benign ganglioneuromas. Several efforts have been made in order to find tumor progression markers. In this work, we have reconstructed the neuroblastoma regulatory network using an information-theoretic approach in order to find genes involved in tumor progression and that could be used as outcome predictors or as therapeutic targets. We have queried the reconstructed neuroblastoma regulatory network using an aggressive neuroblastoma metastasis gene signature in order to find its master regulators (MRs). MRs expression profiles were then investigated in other neuroblastoma datasets so as to detect possible clinical significance. Our analysis pointed MAX as one of the MRs of neuroblastoma progression. We have found that higher MAX expression correlated with favorable patient outcomes. We have also found that MAX expression and protein levels were increased during neuroblastoma SH-SY5Y cells differentiation. We propose that MAX is involved in neuroblastoma progression, possibly increasing cell differentiation by means of regulating the availability of MYC:MAX heterodimers. This mechanism is consistent with the results found in our SH-SY5Y differentiation protocol, suggesting that MAX has a more central role in these cells differentiation than previously reported. Overexpression of MAX has been identified as anti-tumorigenic in other works, but, to our knowledge, this is the first time that the link between the expression of this gene and malignancy was verified under physiological conditions.     

Acquisition of thermotolerance during development of Blastocladiella emersonii

In the fungus Blastocladiella emersonii the synthesis of heat-shock proteins is developmentally regulated; particular subsets of heat-shock proteins are induced by heat shock during sporulation, germination and growth and some heat shock-related proteins are spontaneously expressed during sporulation (Bonato et al., 1987, Eur. J. Biochem., in press). Nevertheless, acquisition of thermotolerance can be induced at any stage of the life cycle. The development of thermotolerance is correlated with the enhanced synthesis of some heat-shock proteins: hsp 82a, hsp 82b, hsp 76, hsp 70, hsp 60, hsp 25, hsp 17b. Other hsps are not specifically involved in thermotolerance.     

Cytogenetic studies in six species of Scinax (Anura,Hylidae) clade Scinax ruber from northern and northeastern Brazil

Scinax species are still underrepresented in cytogenetic studies, mainly with respect to populations from northeastern and northern Brazil. In this study, we provide new chromosomal information on Scinax boesemani, S. camposseabrai, S. garbei, S. pachycrus, S. trilineatus and S. x-signatus, all belonging to clade S. ruber. They were collected at two locations in the Caatinga biome (northeastern Brazil) and at one in the Amazon (northern Brazil) biomes. Chromosomes were analyzed by conventional staining, C-banding, Ag-NOR staining, and fluorochrome staining. All species shared a modal diploid value of 2n = 24 and fundamental arm number (FN) of 48. Moreover, both chromosomal size and morphology were similar to other species in this Scinaxclade. C-banding revealed centromeric heterochromatin in all species, along with terminal species-specific C-bands in some species. Active nucleolar organizer regions (Ag-NORs) were identified at 11q in most species, except for S. boesemani and S. garbei (Ag-NORs at interstitial region of 8q). Differing from most anurans, GC-rich regions were not restricted to NORs, but also coincident with some centromeric and terminal C-bands. These data contribute to the cytotaxonomy of Scinax by providing chromosomal markers and demonstrating the occurrence of microstructural rearrangements and inversions on chromosomal evolution of Scinax.     

In vitro regeneration of Echinacea purpurea from leaf explants

Efficient plant regeneration was achieved via organogenesis from callus cultures derived from leaf tissue of Echinacea purpurea. Proliferating shoot cultures were obtained by placing leaf explants on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP) and naphthaleneacetic acid (NAA) combinations. MS medium supplemented with BAP (4.44 M) and NAA (0.054 M) was the most effective, providing high shoot regeneration frequencies (100%) associated with a high number of shoots per explant (7.7 shoots/explant). Plantlets were rooted on MS medium alone or in combination with different concentrations of indole-3-butyric acid (IBA), and high rooting and survival was achieved using MS media without plant growth regulators (PGR). All plantlets survived acclimatization producing healthy plants in the greenhouse. This study demonstrated that adventitious shoot regeneration of E. purpurea from leaf explants can be a useful method for the multiplication of this important medicinal plant.     

Micropropagation and acclimatization of Hedeoma multiflorum

A method for the micropropagation of Hedeoma multiflorum Benth from shoot tips or nodal segments was developed. Proliferating microshoot cultures were obtained by placing shoot tips or nodal segments on half-strength Murashige and Skoog (1962) medium supplemented with 22.2 μM BA or 22.2 μM BA plus 0.05 μM NAA. Individual shoots were excised and transferred into rooting medium containing auxins (IBA, NAA or IAA). Rooting of shoots was better on half-strength MS medium containing 0.6 μM IAA than on half-strength MS medium without growth regulators. Rooted plantlets were successfully acclimatized to soil. Preconditioning at different sucrose concentrations prior to acclimatization had no effect on plant establishment, but influenced plant quality. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of heat shock on S6 phosphorylation during the development of Blastocladiella emersonii

Summary Changes in phosphorylation of ribosomal protein S6 during heat shock, induction of thermotolerance and recovery from heat shock at different stages of Blastocladiella emersonii development were investigated. Independently of the initial state of S6 phosphorylation (maximal or intermediate), a rapid and complete dephosphorylation of S6 is induced by heat shock and S6 remains unphosphorylated during the acquired thermotolerance. During recovery from heat shock rephosphorylation of S6 occurs always to the levels characteristic of that particular stage, coincidently with the turn off of heat shock protein synthesis.     

cAMP regulation of cell differentiation in Dictyostelium discoideum and the role of the cAMP receptor

DNA polymerases and DNA ligases have been studied during development of the amphibian, axolotl. Three forms of DNA polymerase, I, II, and III, with sedimentation coefficients in sucrose of 9, 6, and 3.1 S, respectively, have been found in the axolotl egg. The activity of these three DNA polymerases is unchanged during early embryonic development. The activity of DNA polymerase III then increases significantly, beginning at the tailbud stage, while the activity of DNA polymerase II increases at the larval stage. DNA polymerase I does not show significant variations during this time. On the basis of their catalytic properties, it appears that DNA polymerases I and II are α-type DNA polymerases whereas DNA polymerase III is a β-type enzyme. Two different DNA ligases are found in the axolotl, one showing a sedimentation coefficient in sucrose of 8.2 S (heavy form) and the other, 6 S (light form). The 6 S enzyme is the major DNA ligase activity found in the egg before and after fertilization. Its activity then decreases during embryonic development. It can be observed again, as the only DNA ligase activity, in some adult tissues. The 8.2 S enzyme appears during the first division cycle of the fertilized egg, is present at all stages of embryonic development, and is absent from the adult tissues tested. Properties of the two DNA ligases at different stages of embryonic development have also been compared.