Search results for "PIGMENTATION"
showing 10 items of 134 documents
Decreasing the chlorophyll a/b ratio in reconstituted LHCII: Structural and functional consequences
1999
Trimeric (bT) and monomeric (bM) light-harvesting complex II (LHCII) with a chlorophyll a/b ratio of 0.03 were reconstituted from the apoprotein overexpressed in Escherichia coli. Chlorophyll/xanthophyll and chlorophyll/protein ratios of bT complexes and 'native' LHCII are rather similar, namely, 0.28 vs 0. 27 and 10.5 +/- 1.5 vs 12, respectively, indicating the replacement of most chlorophyll a molecules with chlorophyll b, leaving one chlorophyll a per trimeric complex. The LD spectrum of the bT complexes strongly suggests that the chlorophyll b molecules adopt orientations similar to those of the chlorophylls a that they replace. The circular dichroism (CD) spectra of bM and bT complexes…
Vibrio palustris sp. nov. and Vibrio spartinae sp. nov., two novel members of the Gazogenes clade, isolated from salt-marsh plants (Arthrocnemum macr…
2017
Two bacterial strains, EAod9T and SMJ21T, isolated from salt-marsh plants, were determined to be related to species of the genus Vibrio from from 16S rRNA sequence comparisons. Their closest phylogenetic relatives are members of the Gazogenes clade, Vibrio mangrovi and Vibrio rhizosphaerae , which show the greatest similarity to the SMJ21TrRNA sequence (97.3 and 97.1 %, respectively), while EAod9T had less than 97.0 % similarity to any other species of the genus Vibrio . Both strains share the basic characteristics of the genus Vibrio , as they are Gram-stain negative, motile, slightly halophilic, facultatively anaerobic bacteria. In addition, they are oxidase-negative and unable to grow on…
Euzebyella saccharophila gen. nov., sp. nov., a marine bacterium of the family Flavobacteriaceae.
2010
Strain 7SM30T , an aerobic marine, Gram-negative, heterotrophic and yellow- to orange-pigmented bacterium isolated from seawater from Castellón, Spain, was characterized using a polyphasic approach. Analysis of the 16S rRNA gene sequence showed that the isolate represented a novel lineage within the family Flavobacteriaceae. The most closely related genera were Pseudozobellia, Zobellia and Kriegella. Cells of strain 7SM30T were non-motile rods that required sea salts for growth, used a wide variety of carbohydrates as sole carbon and energy sources and, unlike species of the genera Pseudozobellia and Zobellia, did not possess flexirubin-type pigment or hydrolyse agar. Strain 7SM30T containe…
A rapid and reliable size-exclusion chromatographic method for determination of kojic dipalmitate in skin-whitening cosmetic products
2007
A size-exclusion chromatographic method has been developed to determine the relatively novel skin-whitening agent called kojic dipalmitate (KDP) in skin-whitening cosmetic products. Preliminary experiments were carried out in order to select the solvent for standard and sample solution, and also for mobile phase composition. A PLGel Mixed-D (polystyrene/divinylbenzene co-polymer) column and isocratic mobile phase of pure tetrahydrofuran (at 1.5 mL min(-1) flow rate) were used. Detection was carried out by means of an UV/vis spectrometry detector set at 248 nm. A study of interferences reveals that KDP can be determined without interferences coming from cosmetic matrices. Most other cosmetic…
Towards noncontact skin melanoma selection by multispectral imaging analysis
2011
A clinical trial comprising 334 pigmented and vascular lesions has been performed in three Riga clinics by means of multispectral imaging analysis. The imaging system Nuance 2.4 (CRi) and self-developed software for mapping of the main skin chromophores were used. Spe- cific features were observed and analyzed for malignant skin melanomas: notably higher absorbance (especially as the difference of optical density relative to the healthy skin), uneven chromophore distribution over the lesion area, and the possibility to select the "melanoma areas" in the correla- tion graphs of chromophores. The obtained results indicate clinical potential of this technology for noncontact selec- tion of mel…
Biochemical approach on the conservation of drug molecules during hair fiber formation
1997
A biochemical concept for the endogenous incorporation of drug molecules into growing hair is presented. It is based on the principles of transport across biomembranes, on the principles of biotransformation and drug melanin affinity. The approach gives explanations for current observations in hair analysis, which up to date have not been understood sufficiently. Phenomena such as the ratio of parent drug to metabolite in hair, the dependence of incorporation on the physico-chemical properties of the drug, the independence of drug incorporation on active melanogenesis (incorporation into non-pigmented hair) as well as the dependence of drug content on hair pigmentation are elucidated.
Adverse drug reactions in the oral cavity
2012
Several drugs may have a number of adverse reactions (ADRs) involving the oro-facial region. The dose of the drug and the time required for the reaction to take place are relevant parameters; nonetheless, ADRs mechanisms are not always known and ADRs are not always predictable since aspects other than drug pharmacodynamics and/or pharmacokinetics, as well as various interacting variables contribute to the final outcome. All tissues and many functions of the oral cavity can be affected. In particular, salivary function is fre- quently involved and hypo-salivation is the main manifestation; several mucosal lesions with different morphology (ulcerations, vesiculo- bullous lesions, white lesion…
Ovicide-induced serosa degeneration and its impact on embryonic development in Manduca sexta (Insecta: Lepidoptera)
2003
Abstract Eggs of Manduca sexta treated with the ovicide Ov. 165049 turn orange, and the embryos later die. The orange pigmentation is at first confined to the serosa, and is accompanied by pathological changes of serosal cells. Lipid vesicles aggregate and spindle-shaped electron-lucent vesicles—normally forming a single layer below the apical cell surface—greatly accumulate. The mitochondria swell considerably, and their matrices become electron-lucent. Subsequently, the serosal cells develop additional features of necrosis. They form many autophagic vacuoles which contain mostly degradating mitochondria, but also segregated rough endoplasmic reticulum (rER) and glycogen granules. The whol…
Temporal relationship between genetic and warning signal variation in the aposematic wood tiger moth (Parasemia plantaginis).
2013
Many plants and animals advertise unpalatability through warning signals in the form of colour and shape. Variation in warning signals within local populations is not expected because they are subject to directional selection. However, mounting evidence of warning signal variation within local populations suggests that other selective forces may be acting. Moreover, different selective pressures may act on the individual components of a warning signal. At present, we have a limited understanding about how multiple selection processes operate simultaneously on warning signal components, and even less about their temporal and spatial dynamics. Here, we examined temporal variation of several w…
Changes in predator community structure shifts the efficacy of two warning signals in Arctiid moths
2013
Summary 1. Polymorphism in warning coloration is puzzling because positive frequency-dependent selection by predators is expected to promote monomorphic warning signals in defended prey. 2. We studied predation on the warning-coloured wood tiger moth (Parasemia plantaginis )b y using artificial prey resembling white and yellow male colour morphs in five separate populations with different naturally occurring morph frequencies. 3. We tested whether predation favours one of the colour morphs over the other and whether that is influenced either by local, natural colour morph frequencies or predator community composition. 4. We found that yellow specimens were attacked less than white ones rega…