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Extractive bioconversions in aqueous two-phase systems

Although extractive bioconversions in aqueous two-phase systems (ATPSs) have been studied for over a decade, this has not yet resulted in widespread industrial application. The main reasons are the cost of the phase-forming polymers and the complexity of ATPS behavior. A number of recent developments may give a new impetus to this technology. First of all, the use of extractive bioconversions in ATPSs has recently been extended to high-value protein products, while in the meantime the development of low-cost ATPSs is ongoing. Furthermore, novel chromatographic methods enable the analysis of polymer and metabolite compositions in complex ATPS mixtures, and recently employed statistical experimental designs provide a tool for efficient data gathering, while they also reveal synergistic effects between process parameters. Together, these developments open the way towards improved modeling of partitioning behavior in ATPSs.

Journal Article↗

Blind multiridge detection for automatic nondestructive testing using ultrasonic signals.

Ultrasonic imaging has been a significant means for nondestructive testing (NDT). Recently the NDT techniques via the ultrasonic instrumentation have shown the striking capability of the quality control for the material fabrication industry. To the best of our knowledge, all existing signal processing methods require either the a priori information of the ultrasonic signature signals or the manual segmentation operation to achieve the reliable parameters that characterize the corresponding mechanical properties. In this paper, we first provide a general mathematical model for the ultrasonic signals collected by the pulse-echo sensors, then design a totally blind novel signal processing NDT technique relying on neither a priori signal information nor any manual effort. Based on the automatic selection of optimal frame sizes using a proposed new criterion in our scheme, the signature signal can be blindly extracted for further robust multiridge detection. The detected ridge information can be used to estimate the transmission and attenuation coefficients associated with any arbitrary material sample for the fabrication quality control.

Journal Article↗

Application of aqueous two-phase systems in separation/purification of stroma free hemoglobin from animal blood.

Aqueous two-phase system (ATPS) is suitable for treatment of biological materials. It has been traditionally employed in the separation of product from fermentation broth, and in the extraction of large-molecule proteins from colloid solution. The separation method based on ATPS features simple, rapid and continuous operation with low equipment cost. A PEG/Salt aqueous two-phase system is studied, and developed for hemoglobin (Hb) separation from animal bloods. Stroma free hemoglobin (SFHb) was extracted from 200ml packed red blood cells by the two-stage aqueous two-phase system and subsequently was desalted and dialyzed by ultrafiltration. It took only 2.5hr to complete overall process to purify SFHb. The purity of SFHb was analyzed by HPLC and IEF (silver staining). Large partition coefficients of Hb have been observed with proper selection of PEG molecular weight, added concentrations of PEG and salt in each phase. The SFHb of very high purity which is free of other proteins (< 0.1% impurity) and phospholipids (< 2% impurities) may be obtained from human packed RBCs. A two-stage extraction design using ATPS separation concept is very simple and useful for purification of SFHb. The method may be further developed to offer potent technology for hemoglobin separation from animal blood and future production industry of blood substitutes.

Animals↗

[Determination of the inhibitory effect of a biologically active preparation on the reproduction of micro-organisms from the intestines of ruminants].

A procedure for the production of biologically active substances from pine and spruce needles was worked out within the research project Utilization of Tree Verdure. The product was referred to as a biologically active preparation. The fields of its possible uses include agriculture (animal production-feeding), cosmetics (production of pastes, soaps, etc.), pharmaceutical industry (after additional conditioning the product can be used for manufacturing medicinal drugs for the control of inflammatory diseases and the like). The biologically active preparation, i. e. the pine needle extract, was studied as to its effect on some of the most numerous microorganisms in the intestines of ruminants. As found, this preparation has a partial inhibitive action on the growth and reproduction of microorganisms. The biologically active preparation is an extract isolated from the needles by means of 0.3% sodium hydroxide. Besides extractive substances it also contains the residues of organellae of cellular nature (which got into the extract through the filter during the process of preparation) and a small amount of fibre (0.33%). The chemical composition of the biologically active preparation is varied: until now about 220 substances, many of which are biologically active, have been found to be present in the product.

Animals↗

Preliminary estimation of the rainfall chemical composition evaluated through the scavenging modeling for north-eastern Amazonian region (Amapá state, Brazil).

Numerical modeling of scavenging processes has been compared with data obtained for rainwater and aerosol chemistry at Serra do Navio, in the state of Amapá in the Brazilian Amazon region. Sulfate, nitrate and ammonium concentrations were determined in rainwater samples collected from May 1995 until June 1997. The levels of these same chemicals were also determined in aerosols for the same period and region. Scavenging processes have been evaluated on a rainfall event basis, via numerical modeling, in order to simulate the rainwater concentrations and compare them with the observed data. RAMS (Regional Atmospheric Modeling System) was used to simulate cloud structures. A model of below-cloud scavenging was evaluated, as well. The determinations made from the results of the scavenging model are the following: a) aerosol vertical profiles are quite important to rainwater concentrations; b) modeled sulfate in rainwater is a better fit to the observed data values than ammonium and nitrate; c) the obtained sulfate aerosol concentrations samples are similar to ones found in the literature, although the sulfate concentrations in rainwater are much lower than other studies in the literature; d) the in-cloud scavenging process dominates, e) our modeled results, using an input gas vertical profile extracted from the ABLE2B experimental data set, present a smaller ratio between gas and aerosol scavenging than found in other studies in the literature, other studies may have had larger rainfall times, which increase the importance of gas phase scavenging.

Aerosols↗

Natural product source material use in the pharmaceutical industry: the Glaxo experience.

Glaxo PLC has had a significant involvement with Natural Product Source Materials for all of its commercial history and, most recently, has pursued this interest by use of such materials as templates for new lead discovery. Through the expertise and facilities in its Natural Products Discovery Department, Glaxo extracts relatively small quantities of plant material (typically 200-250 g dry weight) and cultures microorganisms from environmental samples (typically 10-50 g). Extracts and fermentation broths are screened in order to detect bioactive principles (BPs). If the potency, selectivity and specificity of the BP is acceptable, isolation, purification and structural elucidation follows. It is most unlikely, in our experience, that the BP itself will become a drug; it is much more likely that we shall need to initiate a medicinal chemistry synthesis program in order to try to produce a molecule that has both the essential biological and desirable chemical properties to become a drug development candidate. This synthetic process is often a long one and our confidence that such a process is worth undertaking is greatly improved if the BP is novel. An essential component of any medicinal chemistry strategy is that it allows us to obtain secure intellectual property rights through patents. Acquisition of product claim protection, the strongest form of patent protection, is of great importance. Safety testing and clinical development of the candidate drug can take 7-10 years, and often more, during which patent protection is constantly eroding. Recognizing that acquisition of Natural Products Source Materials is an issue of growing concern, Glaxo Research and Development Ltd. (GRD), in the early part of 1992, implemented a policy for plant supply. This policy was subsequently modified to embrace source materials such as environmental, soil and marine samples from which fungi, micro- and microorganisms may be obtained. As a direct consequence of this policy, Natural Product Source Materials supply agreements are only concluded with national and international organizations who possess the expertise to identify and collect the samples. It is equally important that our suppliers have the authority, which must be provided to GRD in writing, to collect such materials and to provide them to GRD for extraction and screening purposes. Such materials must be from sustainable and accessible sources. We will not seek to collect any endangered species. Though ethnomedical information can be helpful, it is not essential. Plants must be taxonomically classified. We reimburse the supplying institute for their efforts and their expertise, and recognize an obligation to offer a royalty to the institute in the event that drug discovery, with subsequent commercialization, owes its origin, however indirectly, to a material that it provided. In discussions with the institute, we insist that "a fair proportion' (>40%) of that royalty be used for the direct benefit of the people in the collection source area. In this context, GRD recognizes the importance of local training and education.

Drug Evaluation, Preclinical↗

Bioavailability study of tablet Bezafibrate 200 mg (Lipocor).

In order to determine the ultimate quality of any formulated dosage form and rationalize the therapeutic plan as well as to individualize the prescription, in vivo measurement of drug is the modem and specialized expertise of the clinical/research area of pharmacy practice, which provides effectiveness and assures the safety of drugs. All pharmacological, therapeutic or toxic responses are subject to reaching of drug at the site of action through connective tissue. Other than physico chemical properties of drug, there are numerous factors from manufacturing process to biochemical behaviour of the individual which resist in the absorption, distribution, metabolism and elimination of drugs in the biological system. Bezafibrate Tablet 200 mg (Lipocor) an oral conventional formulation manufactured by Efroze Chemical Industries (Pvt.) Ltd. was investigated for bioavailability followed by pharmacokinetic studies on adult, male, healthy, human local population. For this purpose, a sensitive, specific and validated method was used for the estimation of bezafibrate in blood. HPLC was performed on a reversed phase C18 column (flow rate 1.5 ml/min, UV = 230 nm) with 0.02 M buffer of KH2PO4 (Adjusted pH 3.5 with Phosphoric Acid) and Methanol (40: 60) whereas extraction of the drug from the plasma was carried out by deproteinization of plasma according to classical method described in previous studies (Obaid A. et al., 1999). Peak level (Tmax) of Bezafibrate Tablet 200 mg (Lipocor) was observed at about 1.42 +/- 0.53 hours after the dose and practically free Bezafibrate Tablet 200 mg (Lipocor) could be detected in blood after 9 hours. Cmax of the investigated formulation of Lipocor register mark or target was 1732 +/- 374.2 ng/ml. Area under curve (AUC) was 5198.65 +/- 1231.8 ng. hr/ml.

Journal Article↗

[Respiratory system reactions to organic aerosol exposure].

The effects of organic aerosols (coffee, teas, spices, confectionery, soy, animal feed) on the respiratory system of workers occupationally exposed to these aerosols are presented. Described are possible mechanisms responsible for the development of respiratory impairment. Our studies indicate the possibility of development of respiratory impairment in exposed workers. The prevalence of chronic respiratory symptoms and diseases varied from 2.7 to 56.3% and of acute symptoms from 9.9 to 78.9% of exposed workers. Statistically significant acute reductions of ventilatory capacity (FVC, FEV1, FEF50, FEF25) were recorded during the work shift. Described are some immunological changes which can develop in exposure to organic aerosols. Experimental studies with water organic dust extracts on isolated guinea pig trachea suggest that bronchoconstrictive changes in humans may be reproduced in non-sensitized guinea pigs. The need for taking preventive medical examinations in order to prevent development of respiratory and/or immunological impairment is stressed.

Adult↗

Regulation and quality control of herbal drugs in Korea.

Korea has a great diversity in resources of medicinal plants. The traditional herbal medicines and their preparations have been widely used in Korea as well as in China and Japan for thousands of years. One of the characteristics of Korean herbal medicine preparations is that all the herbal medicines are incorporated into an extractor at the same time and extracted with boiling water during the decoction process. In this process, a variety of interactions between the active components of several herbal medicines may occur. This is the main reason why quality control of oriental herbal drug is more difficult than that of western herbal drug. In this paper, we would like to present an overview of the characteristics of regulation and quality control of herbal medicines in Korea.

Drug Industry↗

Preliminary study of the stability of calix[4]arene crown compounds under radiolysis.

The extraction of (135)Cs from high activity waste arising from reprocessing of spent fuel can be achieved by using calix[4]arene crown compounds. The radiolytic degradation of calix[4]arene crowns as well as their solvent, o-nitrophenyloctyl ether (NPOE), was studied using electrospray ionization mass spectrometry (ESI-MS) (that formed Cs(+) or Na(+) adducts) in nitric acid, as well as by chemical ionization tandem mass spectrometry (MS/MS) experiments. The structures of major degradation products were identified with MS and specifically labelled nitric acid. Although NPOE and calix[4]arene crowns alone are relatively stable, under simulated conditions resembling the real industrial processes involving radiolysis in the presence of nitric acid, several products resulting from nitration and oxidation were observed.

Journal Article↗

DsrB gene-based DGGE for community and diversity surveys of sulfate-reducing bacteria.

A denaturing gradient gel electrophoresis (DGGE) method was developed to assess the diversity of dsrB (dissimilatory sulfite reductase beta-subunit)-genes in sulfate-reducing communities. For this purpose a PCR primer pair was optimized for the amplification of a approximately 350 bp dsrB gene fragment that after DGGE gel electrophoresis enabled us to discriminate between dsrB genes of different SRB-subgroups,-genera and -species. The dsrB-DGGE method revealed considerable genetic diversity when applied to DNA extracts obtained from aquifer samples that were derived from monitoring wells of an in situ metal precipitation (ISMP) pilot project conducted at the site of a non-ferrous industry or from environmental heavy metal contaminated samples. The sequences of the excised and sequenced DGGE bands represented dsrB genes of different SRB-subgroups,-genera and -species, thus confirming the broad applicability of the PCR primer pair. Linking the results of the physico-chemical follow-up of the field and lab experiments to the dsrB-DGGE data will provide a better understanding of the contribution of the SRB populations to the ongoing ISMP processes.

Base Sequence↗

Degradation of aflatoxins in peanut kernels/flour by gaseous ozonation and mild heat treatment.

Aflatoxins occur naturally in many agricultural crops causing health hazards and economic losses. Despite improved handling, processing and storage, they remain a problem in the peanut industry. Therefore, new ways to detoxify contaminated products are needed to limit economic/health impacts and add value to the peanut industry. The study was conducted (1) to evaluate the effectiveness of ozonation and mild heat in breaking down aflatoxins in peanut kernels and flour, and (2) to quantify aflatoxin destruction compared with untreated samples. Peanut samples were inoculated with known concentrations of aflatoxins B1, B2, G1 and G2. Samples were subjected to gaseous ozonation and under various temperatures (25, 50, 75 degrees C) and exposure times (5, 10, 15 min). Ozonated and non-ozonated samples were extracted in acetonitrile/water, derivatized in a Kobra cell and quantified by high-performance liquid chromatography. Ozonation efficiency increased with higher temperatures and longer treatment times. Regardless of treatment combinations, aflatoxins B1 and G1 exhibited the highest degradation levels. Higher levels of toxin degradation were achieved in peanut kernels than in flour. The temperature effect lessened as the exposure time increased, suggesting that ozonation at room temperature for 10-15 min could yield degradation levels similar to those achieved at higher temperatures while being more economical.

Aflatoxin B1↗

Evaluation of a local exhaust system used in the manufacture of small parts made of reinforced plastic.

Fiber-reinforced plastics are used to manufacture a large variety of products, particularly for the transportation sector. Hand lay-up molding and projection molding are the main methods of manufacture. The users of these processes are exposed to appreciable emissions of styrene; in Quebec, more than 3000 workers work in this industry. A statistical analysis of styrene concentrations measured over a five-year period by the Institut de recherche en santé et en sécurité du travail (IRSST, Occupational Health and Safety Research Institute) reveals that for all of the main manufacturing sectors involved, between 40 percent and 78 percent of the results exceed the exposure standard of 50 ppm. This study evaluated the effectiveness of a ventilated table in controlling worker exposure to styrene and acetone in a shop that manufactures fiber-reinforced plastics parts. The evaluated local extraction system consists of a ventilated table with a surface area of 1.2 m x 1.2 m. During molding, the styrene emissions are exhausted through the ventilated table as well as through the slots in a lateral hood. Replacement air, introduced vertically through a supply air shower located above the worker, limits the diffusion of contaminants toward the worker's breathing zone. The reduction in worker exposure to styrene and acetone during hand lay-up molding was measured in the breathing zone for two sizes of molds. The results show that exhaust ventilation reduced the styrene concentrations by 91 percent and that the introduction of replacement air increased the efficiency of the ventilated table to 96 percent. The evaluation performed indicates that the ventilated table adequately controls worker exposure to styrene and acetone during the molding of small components.

Acetone↗

Use of two short-term tests to evaluate the genotoxicity of river water treated with different concentration/extraction procedures.

The genotoxicity of river water samples was evaluated by the Salmonella mutagenicity assay and by the microscreen phage-induction assay. Different processes of sample treatment were compared using the following assays: different volumes of a non-concentrated sample (direct method); concentrated sample fractionated into portions with acid, basic and neutral activity (liquid-liquid extraction method); sample submitted to extraction of volatile substances (volatile extraction method). Samples that were positive to the Salmonella assay by the direct concentration method lost this activity after liquid-liquid extraction. This difference was related to the loss of substances that volatilize during the extraction process. The study of volatile product concentrates confirmed the role of these compounds in inducing activity present in some samples. The microscreen phage-induction assay proved to be a good screening assay for genotoxic compounds present in small concentration in environmental samples. We conclude that, whenever possible, samples should be treated by the direct method in different volumes to prevent the loss of genotoxic substances.

Brazil↗

The adjuvants aerosil 200 and Gelita-Sol-P influence on the technological characteristics of spray-dried powders from Passiflora edulis var. flavicarpa.

Passiflora edulis (passionflower) is a plant widely used in the Brazilian popular medicine and phytopharmaceutical industry for its sedative activity. This work refers to the development of spray-dried powders (SDPs) from the 40% ethanolic extractive solution of P. edulis aerial parts. The SDPs were prepared with a Büchi 190 Mini-spray dryer using as drying adjuvants Aerosil 200 alone (SDP1), an Aerosil 200: Gelita-Sol-P (1:1) mixture (SDP2) and an Aerosil 200:Gelita-Sol-P (1:3) mixture (SDP3). All the powders were obtained using 40 parts adjuvant and 60 parts extract dried residue. The comparison criteria applied were particle size distribution, hygroscopicity at 95%, 60%, and 35% relative humidity (RH), as well as the flavonoid process recovery. The particle size distributions were analyzed by way of (a) normal distribution parameters, (b) the RRSB grid and (c) considering diameter values in terms of an equivalent sphere. All the powders presented nonnormal distribution, and the RRSB analysis appeared to be, therefore, the analysis method of choice. The total flavonoid recovery was around 80%, and it was practically not affected by the SDP1, SDP2, and SDP3 compositions. At the 60% and 90% RH atmospheres, the SDP3 and SDP2 moisture uptakes were higher than that of the SDP1. All the formulations were, on the contrary, stable at 35% RH, showing a slight moisture loss tendency. The results showed in sum that the SDP prepared using Aerosil 200 as the drying adjuvant alone presented the best technological characteristics of all.

Adjuvants, Pharmaceutic↗

Industrial-scale production and rapid purification of an archaeal beta-glycosidase expressed in Saccharomyces cerevisiae.

The application of enzymes isolated from extreme thermophiles in biotechnological processes is hampered by their unconventional fermentation conditions. The expression, in mesophilic hosts, of genes encoding for thermophilic proteins enables these difficulties to be overcome and permits the production of enzymes in high yield by using conventional fermentation plants and an efficient enzyme purification utilizing heat precipitation of host proteins. The beta-glycosidase gene from Sulfolobus solfataricus, a thermoacidophilic archaeon growing at 87 degrees C and pH 3.5, has been cloned and expressed in Saccharomyces cerevisiae (baker's yeast). The fermentation of a S. cerevisiae strain on a 100-litre scale and the two-step purification of the expressed beta-glycosidase by cell autolysis and extracts thermal precipitation is described. This procedure, after 72 h of autolysis, gave a yield 56-fold higher with respect to that obtained with the beta-glycosidase from S. solfataricus.

Biotechnology↗

Toxicity characteristic leaching procedure and iron treatment of brass foundry waste.

The Toxicity Characteristic Leaching Procedure (TCLP) is used by the United States Environmental Protection Agency to determine if wastes contain extractable components subject to hazardous waste regulations. This paper examines the limitations of the TCLP and the way it is used by studying a particular example. Waste casting sand from brass foundries to which iron metal has been added passes the TCLP test but when placed in a landfill for several years may start to leach lead, copper, and zinc. Results of TCLP tests of waste sand alone and with the additives iron metal, zinc metal, hydrous ferric oxide, and hematite are reported. Three processes were studied: reduction by metallic iron, sorption by hydrous ferric oxide, and precipitation of hydroxides. Lead, copper, and zinc behave differently with respect to these three processes, and their measurement allows some deductions as to what is occurring in a TCLP test or a landfill. Iron addition does not result in long-term stabilization of a waste placed in the ground. The chemistry of a laboratory extraction can be very different from the chemistry of a waste placed in the environment. Wastes that are treated to pass the TCLP test, but are not permanently stabilized, are a threat to the environment.

Hazardous Waste↗

Fluorometric determination of nitrite in cured meats.

An indirect fluorometric method for determining sodium nitrite in meat products is presented. The extracted sodium nitrite is consumed in a diazotization reaction with a measured excess of sulfanilic acid. Fluorescamine, which acts selectively with primary amines such as sulfanilic acid, is a fluorogenic reagent for the excess amine. The amine consumed, calculated by difference from the total originally present, is directly related to the sodium nitrite content of the sample. Interferences from amino acids and soluble proteins in the meat extract are eliminated by judicious use of a secondary peak in the fluorescence spectra (436 nm excitation, 495 nm fluorescence) combined with measurement at low pH (3.30). The recoveries of sodium nitrite ranged from 83.2 to 99.6% with an average of 93.4 and a standard deviation of +/- 5.28% for 11 determinations.

Food Additives↗