Use of micelles in studying drug-binding sites: simulation of the tubulin-bound fluorescence of colchicine

Enhancement of the fluorescence intensity of colchicine occurs in media of low polarity and appreciable viscosity; this is suggested to be the basis of the intensification of its fluorescence when it is bound to and immobilized in tubulin. We show here that the tubulin-bound fluorescence features of colchicine are largely reconstructed upon solubilizing it in chosen micellar aggregates that offer optimal polarities and microviscosities. Triton X-100 and bile salt micelles intensify the colchicine emission but the maximal effects are obtained with tetrameric aggregates of the peptide melittin. Estimates of the polarity, microviscosity and binding-site dimensions of colchicine are obtained using this mimetic approach. Our results suggest that well chosen micellar systems act as good models to reconstruct and analyze the spectral properties of molecules immobilized in their binding sites.     

An in vitro demonstration of peroxisome proliferation and increase in peroxisomal β-oxidation system mRNAs in cultured rat hepatocytes treated with ciprofibrate

Using the normal adult rat hepatocytes, plated on rat tail collagen-coated dishes and fed a chemically defined medium, we demonstrate here that ciprofibrate at 0.1 mM concentration, increases significantly the mRNA levels of fatty acyl-CoA oxidase, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional protein, and thiolase (the three enzymes of the β-oxidation system), and causes peroxisome proliferation. Increase in mRNA levels of these genes was evident within 1 h and was maximal 24 h after the addition of ciprofibrate. In hepatocytes cultured in the absence of ciprofibrate, the basal levels of these enzymes were low and further declined with time. Concomitant treatment of hepatocytes with cycloheximide did not inhibit or superinduce the mRNA levels, indicating that this induction may represent a primary (direct) effect of this compound on the expression of these genes and does not apparently involve short-lived repressor protein(s).     

Lipids of Cuscuta reflexa and changes in lipids of its host plants after infection

The lipid level (fresh weight basis) of Cuscuta reflexa Roxb. was related to the lipid content of the host plants Meilicago saliva L., Helianthus annuus L., Pisum sativum L. and Lantana camara L. Parasitizing by the dodder significantly increased the total lipid level of the hosts. The increase was mainly due to enhancement in the neutral lipid fraction.
The level of phospholipid in the parasite was always higher than in its hosts. Phospholidyl choline and phosphatidyl ethanolamine constituted about 65% of the total phospholipid of Cuscuta. This was followed by phosphatidyl inositol (ca 20%) and phosphatidyl glycerol (ca 12%). Phosphatidic acid constituted only ca 3% of the phospholipids of Cuscuta. Although the total phospholipid levels of various host plants were not affected as a result of the infection by Cuscuta, a significant decrease occurred in the levels of phosphatidyl eholine and phosphatidyl ethanolamine as well as marked increases in phosphatidyl inositol and phosphatidic acid. The infected tissue showed an increase in phospholipase D activity as compared with the controls. The results have been discussed in relation to changes in permeability of the infected tissue.     

DETERMINATION OF GUSTATORY SUCROSE THRESHOLD IN WATER BY USE OF A LINEAR SUCROSE GRADIENT

A novel experimental method was developed which allows the determination of the threshold concentration of sucrose by use of a linear sucrose gradient in water. With this method a continuous tasting of the test-liquid is possible. A panel of 15 persons experienced in taste-testing was used. Three gradients of different steepness were applied: 0 to 1.5% (w/w) sucrose in 2 min (I), 3 min (II) and 4 min (III). The results of the new method were compared with those of the standard method (DIN). With gradients I and II we found values which were significantly higher than those of the standard method (I: 0.49% (w/w); II: 0.46% (w/w); DIN: 0.31% (w/w)), whereas with gradient III the same threshold value was found as with the DIN-Method (III: 0.32% (w/w)).     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Cissogenin,a pregnane genin from Marsdenia tenacissima

A new polyhydroxy pregnane designated as cissogenin has been isolated from the seeds of Marsdenia tenacissima. Its structure has been established as 3β,11α,12β,14β,20 S-pentahydroxy-pregn-5-ene.     

Probiotic Attributes and Inhibitory Effects of Lactobacillus plantarum MYS84 against the Growth and Biofilm Formation of Pseudomonas aeruginosa

Microbiology - Manufacture of fermented foods/products, which, apart from basic nutrition, have health-promoting effects, is flourishing. Within the field of fermented foods, rapidly expanding is...     

Proteomic profiling of serum samples from chikungunya-infected patients provides insights into host response

Background

Chikungunya is a highly debilitating febrile illness caused by Chikungunya virus, a single-stranded RNA virus, which is transmitted by Aedes aegypti or Aedes albopictus mosquito species. The pathogenesis and host responses in individuals infected with the chikungunya virus are not well understood at the molecular level. We carried out proteomic profiling of serum samples from chikungunya patients in order to identify molecules associated with the host response to infection by this virus.

Results

Proteomic profiling of serum obtained from the infected individuals resulted in identification of 569 proteins. Of these, 63 proteins were found to be differentially expressed (≥ 2-fold) in patient as compared to control sera. These differentially expressed proteins were involved in various processes such as lipid metabolism, immune response, transport, signal transduction and apoptosis.

Conclusions

This is the first report providing a global proteomic profile of serum samples from individuals infected with the chikungunya virus. Our data provide an insight into the proteins that are involved as host response factors during an infection. These proteins include clusterin, apolipoproteins and S100A family of proteins.     

Delimitation of the maritime boundary in the gulf of Maine area

The compulsory dispute settlement regime included in the 1982 Law of the Sea Convention is recognized as one of the most comprehensive in a modern international convention. Yet, in the recent application of this regime, the question has arisen as to whether the procedural prerequisites associated with the LOS Convention's compulsory dispute settlement mechanism are so arduous as to avoid binding and compulsory jurisdiction in most instances. This article addresses that question by examining, in particular, the reasoning of the Southern Bluefin Tuna arbitration tribunal, which found Article 281 of Section 1 of the LOS Convention to bar jurisdiction to the compulsory dispute settlement mechanism prescribed by the Convention, and offers suggestions as to how states might distinguish or overcome the barriers imposed by the Southern Bluefin Tuna tribunal in future cases.     

Auto-validation of fluorescent primer extension genotyping assay using signal clustering and neural networks

Background

SNP genotyping typically incorporates a review step to ensure that the genotype calls for a particular SNP are correct. For high-throughput genotyping, such as that provided by the GenomeLab SNPstream^® instrument from Beckman Coulter, Inc., the manual review used for low-volume genotyping becomes a major bottleneck. The work reported here describes the application of a neural network to automate the review of results.

Results

We describe an approach to reviewing the quality of primer extension 2-color fluorescent reactions by clustering optical signals obtained from multiple samples and a single reaction set-up. The method evaluates the quality of the signal clusters from the genotyping results. We developed 64 scores to measure the geometry and position of the signal clusters. The expected signal distribution was represented by a distribution of a 64-component parametric vector obtained by training the two-layer neural network onto a set of 10,968 manually reviewed 2D plots containing the signal clusters.

Conclusion

The neural network approach described in this paper may be used with results from the GenomeLab SNPstream instrument for high-throughput SNP genotyping. The overall correlation with manual revision was 0.844. The approach can be applied to a quality review of results from other high-throughput fluorescent-based biochemical assays in a high-throughput mode.