Intracellular accumulation of polyphosphate by the yeast Candida humicola G-1 in response to acid pH

Cells of a newly isolated environmental strain of Candida humicola accumulated 10-fold more polyphosphate (polyP), during active growth, when grown in complete glucose-mineral salts medium at pH 5.5 than when grown at pH 7.5. Neither phosphate starvation, nutrient limitation, nor anaerobiosis was required to induce polyP formation. An increase in intracellular polyP was accompanied by a 4.5-fold increase in phosphate uptake from the medium and sixfold-higher levels of cellular polyphosphate kinase activity. This novel accumulation of polyP by C. humicola G-1 in response to acid pH provides further evidence as to the importance of polyP in the physiological adaptation of microbial cells during growth and development and in their response to environmental stresses.

Aminolaevulinic acid diffusion characteristics in 'in vitro' normal human skin and actinic keratosis: implications for topical photodynamic therapy

Background: The response rate of aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) in certain subtypes of actinic keratosis (AK), such as hypertrophic and hyperkeratotic lesions, is variable, an effect attributable to a supposed lack of ALA penetration. A detailed and depth-related profile of spatial ALA permeation in AK following drug administration would lead to a greater understanding of concentrations achievable before protoporphyrin IX biosynthesis and subsequent PDT.

Three component coupling reactions of N-acetyl-2-azetine-rapid stereoselective entry to 2,3,4-trisubstituted tetrahydroquinolines

N-Acetyl-2-azetine undergoes Lewis acid catalysed [4 + 2]-cycloaddition with imines derived from aromatic amines and gave a 1:1 mixture of exo-endo diastereoisomeric azetidine cycloadducts which reacted further with aromatic amine, to give 2,3,4-trisubsitituted tetrahydroquinolines in good to excellent yield, predominantly as one diastereoisomer.

Lipid content and fatty acid composition of the digital cushion of bulls offered different amounts of linseed

Previous research suggests that the digital cushion, a shock-absorbing structure in the claw, plays an important role in protecting cattle from lameness. This study aimed to assess the degree to which nutritional factors influence the composition of the digital cushion. This involved quantifying lipid content and fatty acid composition differences in digital cushion tissue from cattle offered diets with different amounts of linseed. Forty-six bulls were allocated to 1 of 4 treatments, which were applied for an average of 140 +/- 27 d during the finishing period. The treatments consisted of a linseed supplement offered once daily on top of the basal diet (grass silage:concentrate) at 0, 400, 800, or 1,200 g of supplement/animal per day. For each treatment, the concentrate offered was adjusted to ensure that total estimated ME intake was constant across treatments. Target BW at slaughter was 540 kg. Legs were collected in 3 batches after 120, 147 and 185 d on experiment. Six samples of the digital cushion were dissected from the right lateral hind claw of each animal. Lipids were extracted and expressed as a proportion of fresh tissue, and fatty acid composition of the digital cushion was determined by gas chromatography. Data were analyzed by ANOVA, with diet, location within the digital cushion, and their interactions as fixed effects and fat content (grams per 100 g of tissue) as a covariate. Linear or quadratic contrasts were examined. The lipid content of digital cushion tissue differed between sampling locations (P

Moisture-Activated Rheological Structuring of Nonaqueous Poloxamine–Poly(Acrylic Acid) Systems Designed as Novel Biomedical Implants

This study reports the formulation/characterisation of novel polymeric platforms designed to behave as low-viscosity systems in the nonaqueous state, however, following uptake of aqueous ?uids, exhibit rheological structuring and mucoadhesion. The rheological/mechanical and mucoadhesive properties of platforms containing poly(acrylic acid) (PAA, 1%, 3%, 5%, w/w) and poloxamines (Tetronic 904, 901, 704, 701, 304), both in the absence and presence of phosphate buffered saline (PBS, pH 7.4) are described. With the exception of Tetronic 904, all formulations exhibited Newtonian ?ow in the nonaqueous state, whereas, all aqueous formulations displayed pseudoplastic ?ow. The consistency and viscoelastic properties were dependent on the concentrations of PAA and PBS and Tetronic grade. PBS signi?cantly increased the consistency, viscoelasticity and mucoadhesion, reaching a maximum at a de?ned concentration of PBS that was dependent on PAA concentration and Tetronic grade. Formulations containing Tetronic 904 exhibited greatest consistency and elasticity both prior to and after dilution with PBS. Increasing PAA concentration enhanced the mucoadhesive properties. Prolonged drug release of metronidazole was observed from formulations containing 10% (w/w) PBS, 3% and, particularly, 5% (w/w) PAA. It is suggested that the physicochemical properties of formulations containing 3% or 5% (w/w) PAA and Tetronic 904, would render them suitable platforms for administration to body cavities.

Non-thiazolidinedione antihyperglycemic agents. Part 4: synthesis of ( )-, (R)-(+)- and (S)-(-)-enantiomers of 2-oxy-3-arylpropanoic acids

. Haigh, David; Birrell, Helen C.; Cantello, Barrie C. C.; Hindley, Richard M.; Ramaswamy, Anantha; Rami, Harshad K.; Stevens, Nicola C. Department of Medicinal Chemistry, SmithKline Beecham Pharmaceuticals, Essex, UK. Tetrahedron: Asymmetry (1999), 10(7), 1335-1351. Publisher: Elsevier Science Ltd., CODEN: TASYE3 ISSN: 0957-4166. Journal written in English. CAN 131:144536 AN 1999:369513 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R)) Abstract The synthesis of a new series of potent 2-oxy-3-arylpropanoic acid antihyperglycemic agents in both racemic and non-racemic form is described. (the biol. activity of these compds. was not reported here). Resoln. of racemic acids is accomplished via amide formation with either (S)-2-phenylglycinol or (S)-4-benzyl-2-oxazolidinone as complementary resolving agents. The target compds. were ?-alkoxy-4-[2-[(2-benzoxazolyl)amino]ethoxy]benzenepropanoic acid derivs.

N-H insertion reactions of rhodium carbenoids. Part 1. Preparation of  -amino acid and  -aminophosphonic acid derivatives.

Rh(II) acetate-catalyzed decompn. of diazophenylacetates PhC(N2)CO2Me 1 and PhC(N2)CO2R* 3 [R*OH = (-)-borneol, (+)-menthol, (-)-8-phenylmenthol] in the presence of a range of N-H compds. results in an N-H insertion reaction of the intermediate carbenoids and formation of N-substituted phenylglycine derivs. PhCH(NR1R2)CO2Me 2 [R1 = R2 = Et; R1 = 4-MeOC6H4, COCH2CHMe2, CO2CH2Ph, (S)-CH(CO2Me)CH2Ph, (S)-CHMePh, R2 = H; 64-83% yields] and PhCH(NR1R2)CO2R* 4 (R1 = R2 = Et; R1 = COMe, CO2Me, R2 = H; same R*; 37-71% yields). The corresponding reactions of di-Me ?-diazobenzylphosphonate PhC(N2)P(O)(OMe)2 5 with primary amines constitute a simple route to aminophosphonates PhCH(NHR)P(O)(OMe)2 6 (R = COMe, COEt, CO2CH2Ph, CO2CMe3, 4-ClC6H4, 4-MeC6H4, 4-MeOC6H4; 13-96% yields).

Thermophysical Properties of Amino Acid-Based Ionic Liquids

Ionic liquids (ILs) having either cations or anions derived from naturally occurring amino acids have been synthesized and characterized as amino acid-based ionic liquids (AAILs) In this work, the experimental measurements of the temperature dependence or density. viscosity, heat capacity, and thermal conductivity of several AAILs, namely, tributylmethylammonium serinate ([N-444][Ser], tributylmethylammonium taurmate ([N-444][Tau]) tributylmethylammonium lysinate a [N-444][ Lys]), tributylmethylammonium threonate ([N-444][Thr]), tetrabutylphosphonium serinate ([P-4444][Ser]), tetrabutylphosphonium taurmate ([P-4444][Tau]), tetrabutylphosphonium lysinate ([P-4444][Lys]), tetrabutylphosphonium threonate P-4444 Thr tetrabutylphosphonium prolinate P-4444 ((Pro(), tetrabutylphosphonium valinate ([P-4444][Val]), and tetrabutylphosphonium cysteinate ([P-4444][Cys]), are presented The influence of cations and anions on studied properties is discussed. On the basis of experimental data. the QSPR (quantitative structure property relationship) correlations and group contribution methods for thermophysical properties of AAILs have been developed, which form the basis for the development of the computer-aided molecular design (CAMD) of AAILs It has also been demonstrated that that the predictive data obtained by con elation methods ale in good agreement with the experimental data The correlations developed, herein. can thus be used to evaluate the studied thermophysical properties of AAILs for use in process design or in the CAMD of new AAILs

Investigation of swelling and network parameters of poly (ethylene glycol)-crosslinked poly (methyl vinyl ether-co-maleic acid) hydrogels

he influence of poly(ethylene glycol) (PEG) plasticiser content and molecular weight on the physicochemical properties of films cast from aqueous blends of poly(methyl vinyl ether-co-maleic acid) was investigated using thermal analysis, swelling studies, scanning electron microscopy (SEM) and attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy revealed a shift of the CO peak from 1708 to 1731 cm-1, indicating that an esterification reaction had occurred upon heating, thus producing crosslinked films. Higher molecular weight PEGs (10,000 and 1000 Da, respectively), having greater chain length, producing hydrogel networks with lower crosslink densities and higher average molecular weight between two consecutive crosslinks. Accordingly, such materials exhibited higher swelling rates. Hydrogels crosslinked with a low molecular weight PEG (PEG 200) showed rigid networks with high crosslink densities and, therefore, lower swelling rates. Polymer:plasticizer ratio alteration did not yield any discernable patterns, regardless of the method of analysis. The polymer–water interaction parameter (?) increased with increases in the crosslink density. SEM studies showed that porosity of the crosslinked films increased with increasing PEG MW, confirming what had been observed with swelling studies and thermal analysis, that the crosslink density must be decreased as the Mw of the crosslinker is increased. Hydrogels containing PMVE/MA/PEG 10,000 could be used for rapid delivery of drug, due to their low crosslink density. Moderately crosslinked PMVE/MA/PEG 1000 hydrogels or highly crosslinked PMVE/MA/PEG 200 systems could then be used in controlling the drug delivery rates. We are currently evaluating these systems, both alone and in combination, for use in sustained release drug delivery devices.

Separation of acid-dyes mixture by bamboo derived active carbon

In the present study, the activated carbon is produced using phosphoric acid treatment of the waste bamboo scaffolding and activated at either 400 or 600 °C. The effect of acid to bamboo ratio (Xp) up to 2.4 has been studied. The BET surface area increased with increasing Xp and activating temperature. BET surface area up to 2500 m2/g carbon has been produced. In order to simulate effluent treatment from textile industry, the produced carbon was tested for its dye adsorption capacities. Two acid dyes with different molecular sizes were used, namely Acid Yellow 117 (AY117) and Acid Blue 25 (AB25). In a single component system, it was found that dye with smaller molecular size, AB25, was readily adsorbed onto the carbon while the larger size dye, AY117, showed little adsorption. As a result, it is possible to tailor-make the carbon for the adsorption of dye mixtures in industrial applications, especially textile dyeing, i.e. molecular sieve effect. A binary AY117–AB25 mixture was used to test the possibility of the molecular sieve effect. Furthermore, experimental results were fitted to equilibrium isotherm models, Langmuir, Freundlich and Sips for the single component system. For the binary component system, extended single-component equilibrium isotherm models were used to predict the experimental data.

Development of ELISAs for detecting domoic acid, okadaic acid, and saxitoxin and their applicability for the detection of marine toxins in samples collected in Belgium

Okadaic acid, a diarrhetic shellfish poison, domoic acid, an amnesic shellfish poison, and saxitoxin, a paralytic shellfish poison, are three of the best-known marine biotoxins. The mouse bioassay is the method most widely used to detect many of these toxins in shellfish samples, but animal welfare concerns have prompted researchers to seek alternative methods of detection. In this study, three direct competitive enzyme-linked immunosorbent assays (ELISAs), each based on antibodies raised in rabbits against a conjugate of the analyte of interest, were developed for marine biotoxin detection in mussel, oyster, and scallop. One assay was for okadaic acid, one for saxitoxin, and one for domoic acid usually detected and quantified by high-performance liquid chromatography-ultraviolet light (HPLC-UV). All three compounds and a number of related toxins were extracted quickly and simply from the shellfish matrices with a 9 : 1 mixture of ethanol and water before analysis. The detection capabilities (CC values) of the developed ELISAs were 150 mu g kg-1 for okadaic acid, 50 mu g kg-1 for domoic acid, and 5 mu g kg-1 or less for saxitoxin. The assays proved satisfactory when used over a 4-month period for the analysis of 110 real samples collected in Belgium.

Immunobiosensor detection of domoic acid as a screening test in bivalve molluscs: Comparison with liquid chromatography-based analysis

A rapid and sensitive immuno-based screening method was developed to detect domoic acid (DA) present in extracts of shellfish species using a surface plasmon resonance-based optical biosensor. A rabbit polyclonal antibody raised against DA was mixed with standard or sample extracts and allowed to interact with DA immobilized onto a sensor chip surface. The characterization of the antibody strongly suggested high cross-reactivity with DA and important isomers of the toxin. The binding of this antibody to the sensor chip surface was inhibited in the presence of DA in either standard solutions or sample extracts. The DA chip surface proved to be highly stable, achieving approximately 800 analyses per chip without any loss of surface activity. A single analytical cycle (sample injection, chip regeneration, and system wash) took 10 min to complete. Sample analysis (scallops, mussels, cockles, oysters) was achieved by simple extraction with methanol. These extracts were then filtered and diluted before analysis. Detection limits in the ng/g range were achieved by the assay; however, the assay parameters chosen allowed the test to be performed most accurately at the European Union's official action limit for DA of 20 mu g/g. At this concentration, intra- and interassay variations were measured for a range of shellfish species and ranged from 4.5 to 7.4% and 2.3 to 9.7%, respectively.

Dose-dependent effects of folic acid on blood concentrations of homocysteine: a meta-analysis of the randomized trials

Background: Dietary supplementation with B vitamins that lower blood homocysteine concentrations is expected to reduce cardiovascular disease risk, but there has been uncertainty about the optimum regimen to use for this purpose.