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[en] Dietary cholesterol should be limited to less than 200 mg/ day. A single large egg yolk contains approximately 275 mg of cholesterol. Thus, consumption of a single egg yolk exceeds the recommended daily intake of cholesterol. This study was focused on determination of the effect of addition of increasing amount of β-cyclodextrin (β-CD) to encapsulate cholesterol in egg yolk. The quality of cholesterol-reduced egg yolk powder was evaluated by determining its nutritional composition and colour analysis. Increasing amount of β-CD (0-15 mM) was added in liquid egg yolk and the encapsulated cholesterol in the form of precipitate was removed. The supernatant was dried and the end product; cholesterol-reduced egg yolk powder (CREYP) was analyzed for moisture content, total lipid, fatty acids content, protein and colour. There were no significant difference (p>0.05) in term of total solid content. However, protein content of CREYP was significantly (p<0.05) reduced up to 7 mM β-CD and no further significant reduction was noticed with further addition of β-cyclodextrin. The appearance of the powder became lighter in colour as validated using chromameter; L*, a*, b*, C* and ho values. The results obtained from this study indicate that cholesterol can be successfully removed from egg yolk. However, slight reduction in protein content was observed. Nutritional composition of CREYP was minimally affected with the removal of encapsulated cholesterol. Therefore, cholesterol-reduced egg yolk powder can be utilized as an essential ingredient in any egg yolk based products. (author)
[en] Four new steroidal constituents, named phyllanthusergostanol, fraternustigmasterol, pyllanfraternusterol and cyclophyllanthusterol, have been isolated from the alchoholic extract of the roots of Phyllanthus Fraternus. The structure of these compounds have been established as ergoster-5, 20(22)-diene-3b, 24a-diol, stigmaster-5, 20(22)-diene-3-ol, stigmaster 9, 20(22)-diene-3b-yl acetate and 19-cyclocholester-25(26)-ene-3b, 18, 27-triol, respectively on the basis of chemical reactions and spectral data. (author)
[en] The Adult Health Study (AHS), a program of biennial medical surveillance of the atomic bomb survivors of Hiroshima and Nagasaki, conducted in the Clinics of the Radiation Effects Research Foundation in the two cities, comprised, in 1958, when the study began, some 20,000 individuals, about half of whom were within 2000 meters of the hypocenters in 1945 at the time of the bomb, the remaining half being either beyond 3000 meters or not in the city at that time. The program, now in its 13th cycle of examinations, was preceded by a number of earlier studies of various exposed and control populations, which, by the mid 1950s were considered to be inadequately defined and therefore not suitable for long-term epidemiological investigations of the late medical and biological effects of exposure among the survivors in the two cities. Although the AHS has yielded considerable data relating to radiation exposure (carcinomas, other somatic effects), it also is an invaluable and unique epidemiological resource for the study of health and disease in a well defined closed population. 37 references, 4 figures
[en] Daxx is a highly conserved nuclear transcriptional factor, which has been implicated in many nuclear processes including transcription and cell cycle regulation. Our previous study demonstrated Daxx also plays a role in regulation of intracellular cholesterol content. Daxx contains several domains that are essential for interaction with a growing number of proteins. To delineate the underlying mechanism of hypocholesterolemic activity of Daxx, we constructed a set of plasmids which can be used to overexpress different fragments of Daxx and transfected to HepG2 cells. We found that the C- terminal region Daxx626–740 clearly reduced intracellular cholesterol levels and inhibited the expression of SREBPs and SCAP. In GST pull-down experiments and Double immunofluorescence assays, Daxx626–740 was demonstrated to bind directly to androgen receptor (AR). Our findings suggest that the interaction of Daxx626-740 and AR abolishes the AR-mediated activation of SCAP/SREBPs pathway, which suppresses the de novo cholesterol synthesis. Thus, C-terminal domain of Daxx acts as a potential regulator of intracellular cholesterol content in HepG2 cells. - Highlights: • Daxx C-terminal domain reduces cholesterol levels. • Daxx C-terminal domain binds directly to AR. • The interaction of Daxx C-terminal domain and AR suppresses cholesterol synthesis.
[en] Background and Aims: Sterols have been reported to modulate conformation and hence the function of several membrane proteins. One such group is the Chloride Intracellular Ion Channel (CLIC) family of proteins. The CLIC protein family consists of six evolutionarily conserved protein members in vertebrates. These proteins are unusual, existing as both monomeric soluble proteins and as membrane bound proteins. We now for the first time demonstrate that the spontaneous membrane insertion of CLIC1 is dependent on the presence of cholesterol in membranes. Our novel findings also extend to the identification of a cholesterol-binding domain within CLIC1 that facilitates the spontaneous membrane insertion of the protein into membranes containing cholesterol. Methods: CLIC1 wild type (WT) and mutant proteins were purified by Ni-NTA followed by size‐exclusion chromatography. Langmuir monolayer film balance experiments were carried out using 1-Palmitoyl-2-oleoylphosphatidylcholine (POPC) alone, or in a 5:1 mole ratio combination with either one of the following sterols: Cholesterol (CHOL), β-Sitosterol (SITO), Ergosterol (ERG), Hydroxyecdysone (HYD) or Cholestane (CHOS). WT CLIC1 or mutant versions of CLIC1 were then injected into the aqueous subphase under the lipid film. Results: In lipid monolayers lacking sterols, CLIC1 did not insert. However significant membrane insertion occurred when CLIC1 was added to membranes containing cholesterol. Substitution of membrane cholesterol with either HYD, SITO or ERG, not only increased CLIC1’s membrane interaction but also increased its rate of insertion. Conversely, CLIC1 showed no insertion into monolayers containing CHOS, which lacked the intact sterol 3β-OH group. CLIC1 mutants G18A and G22A, did not insert in POPC:CHOL monolayers whereas the C24A mutant showed membrane insertion equivalent to WT CLIC1. X-ray and Neutron reflectivity, along with Small Angle X-ray Scattering techniques were subsequently used to probe structural features of the membrane bound CLIC1 and CLIC1-Cholesterol complex in solution. Conclusion: These findings confirm that the GXXXG motif within CLIC1 acts as a sterol binding site facilitating the protein’s membrane interaction and insertion. Critical to this process of spontaneous membrane insertion is the presence of an intact 3β-OH group within the sterol structure itself. Furthermore, additional double bonds and methylation of the steroid skeleton enhanced CLIC1 membrane insertion.
[en] We report here a novel carrier of quantum dots (QDs) for intracellular labeling. Monodisperse hybrid nanoparticles (38 nm in diameter) of QDs were prepared by simple mixing with nanogels of cholesterol-bearing pullulan (CHP) modified with amino groups (CHPNH2). The CHPNH2-QD nanoparticles were effectively internalized into the various human cells examined. The efficiency of cellular uptake was much higher than that of a conventional carrier, cationic liposome. These hybrid nanoparticles could be a promising fluorescent probe for bioimaging
[en] A model was developed that can be used to study the effect of gradual cholesterol intake by food on the HPA axis dynamics. Namely, well defined oscillatory dynamics of vital neuroendocrine hypothalamic-pituitary-adrenal (HPA) axis has proven to be necessary for maintaining regular basal physiology and formulating appropriate stress response to various types of perturbations. Cholesterol, as a precursor of all steroid HPA axis hormones, can alter the dynamics of HPA axis. To analyse its particular influence on the HPA axis dynamics we used stoichiometric model of HPA axis activity, and simulate cholesterol perturbations in the form of finite duration pulses, with asymmetrically distributed concentration profile. Our numerical simulations showed that there is a complex, nonlinear dependence between the HPA axis responsiveness and different forms of applied cholesterol concentration pulses, indicating the significance of kinetic modelling, and dynamical systems theory for the understanding of large-scale self-regulatory, and homeostatic processes within this neuroendocrine system.
[en] Zingiber officinale var. Rubrum (ZOR) is cultivated for its medicinal value despite the constraints of longer life cycle. The study has established an efficient and reproducible protocol to micropropagate ZOR using buds generated on the surface of the ginger. Surface sterilized young buds of 0.5-1 cm and 2-4 cm cultured on Murashige and Skoog (MS) supplemented with BAP showed the highest survival rate (55-65%) and produced the highest average number of microshoots per explant (3.2±0.06) respectively. MS medium supplemented with different concentrations and combinations of auxin and cytokinin were used to evaluate shoot multiplication and root induction. BAP concentrations between 3.0-5.0 mg/L was very effective in promoting microshoots and resulted in 100% of microshoot propagation. Microshoots cultured on MS medium supplemented with 3 mg/L BAP and 0.5 mg/L NAA produced the highest number of shoots while 0-0.5 mg/L BAP enhanced shoot length and 3mg/L NAA in combination with BAP produced highest number of roots. Microshoots maintained on MS medium supplemented with 4.5% sucrose produced the highest number of plantlets (23±2.5) and roots per explants (15.4±2.4) meanwhile reducing the length of lateral roots (2.6±0.2). (author)
[en] Leaf epidermal studies have been carried out on eleven species belonging to Fagopyrum Mill., and Rumex L. of the family Polygonaceae. Comprehensive micro morphological studies of Fagopyrum Mill., and Rumex L. species have been made for the first time. The use of light microscopy has made possible in depth to study leaf surface features such as shape of epidermal cells, stomatal pattern, their distribution on adaxial and abaxial leaf surface and trichome types. Epidermal cell shapes are variable but generally polygonal. Five different stomatal patterns are reported for Polygonaceae. Variation among glandular and non glandular trichomes is also noted. Crystalliferous cells are recorded for the first time in Rumex nepalensis Spreng. This anatomical study has taxonomic importance, on the basis of which identification keys are prepared. (author)
[en] Methyl (3R*,5S*)-(E)-3,5-dihydroxy-9,9-diphenyl-6,8-nonadienoate (1) is a competitive inhibitor of HMG-CoA reductase, the rate-limiting step in cholesterol biosynthesis. We synthesized 1 with a tritium label at C3 in order to investigate tissue selectivity. The synthesis began with β-phenyl-cinnamaldehyde which was homologated to (E)-5,5-diphenyl-2,4-pentadienal in three steps. Addition of the dianion of methyl acetoacetate gave methyl (E)-5-hydroxy-9,9-diphenyl-3-oxo-6,8-nonadienoate. Diastereoselective introduction of the tritium label was achieved using tritium labelled sodium borohydride, triethylborane and a catalytic amount of pivalic acid. The radiochemical yield for this step was 7.5%, the specific activity was 13.3 mCi/mmole, and the product was >95% radiochemically pure. This method may be applicable to the preparation of other radiolabelled HMG-CoA reductase inhibitors which possess a 3,5-dihydroxy acid moiety. (author)