Cell Rupture (cell + rupture)

Distribution by Scientific Domains


Selected Abstracts


Comparison of conventional and ultrasound-assisted extraction of carvone and limonene from caraway seeds

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2004
Smain Chemat
Abstract Extraction experiments with hexane were carried out at atmospheric pressure in Soxhlet, conventional and ultrasound extractions of ,aked caraway seeds, and detailed results are given for two major plant extract components, carvone and limonene. The results indicate that carvone yield and plant extract quality are better in ultrasound extraction compared to those given by conventional methodology. Extraction rates of carvone and limonene reported that ultrasound-assisted extraction was 1.3,2 times more rapid, depending on temperature, than a conventional system, according to the rate constant obtained during the initial 10 minutes of extraction. Moreover, the SEM micrographs provided more evidence for the mechanical effects of ultrasound, mainly appearing on cell walls and shown by the destruction of cells, faulitating the release of their contents, in contrast to conventional maceration or extraction, which involve diffusion of plant extracts across glandular walls and causing cell rupture over longer time periods. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Study of the bio-production of carotenoids by Sporidiobolus salmonicolor (CBS 2636) using pre-treated agro-industrial substrates

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2008
Eunice Valduga
Abstract BACKGROUND: The increasing industrial demand for carotenoids has aroused interest in their bio-production, and the need to reduce production costs has encouraged the use of low cost industrial substrates, such as agro-industrial residues. Thus the objective of this research was the bio-production of carotenoids by Sporidiobolus salmonicolor using agro-industrial substrates (corn steep liquor and sugarcane molasses), pre-treated with acids (sulphuric and phosphoric). RESULTS: Bio-production was carried out in an orbital shaker using a 10% (v/v) inoculum, incubation at 25 °C, and agitation at 180 rpm for 120 h in a non-illuminated environment. The carotenoids were recovered using liquid N2 combined with dimethylsulphoxide for cell rupture, and an acetone/methanol mixture (7:3 v/v) for extraction. CONCLUSION: The complete second-order design allowed for optimisation of the carotenoid concentration obtained from industrial substrates pre-treated with acids (sulphuric and phosphoric), obtaining a total carotenoid content of 541.5 µg L,1 using 10 g L,1 sugarcane molasses, 5 g L,1 corn steep liquor and 5 g L,1 yeast hydrolysate at 25 °C, with agitation at 180 rpm and an initial pH of 4.0. Copyright © 2008 Society of Chemical Industry [source]


Oxidative metabolism by Thalassiosira weissflogii (Bacillariophyceae) of a diol-ester of okadaic acid, the diarrhetic shellfish poisoning

JOURNAL OF PHYCOLOGY, Issue 2 2000
Anthony J. Windust
Previous investigations into the comparative toxicity of the diarrhetic shellfish poisoning (DSP) toxins to Thalassiosira weissflogii (Grun.) Fryxell et Hasle found that this diatom oxidatively metabolized okadaic acid diol-ester (OA diol-ester) to a more water-soluble product. This oxidative transformation of OA diol-ester by the diatom is significant for two reasons. First, it is known that dinophysistoxin-4 (DTX-4), the primary DSP toxin produced by the dinoflagellate Exuviaella lima (Ehr.) Butschli, will be hydrolyzed to the diol-ester following cell rupture (e.g. ingestion by a predator). Second, it implies that the ester, an uncharged, lipophilic intermediate, can easily enter cells and therefore may play an important role in the uptake and transfer of DSP toxins through the food web. It has been suggested that the water soluble DTX-4 may also be the form in which DSP toxins are excreted from the producing cell. Therefore, the stability of DTX-4 was examined when incubated either in fresh seawater medium into which washed cells of E. lima were introduced or in seawater medium conditioned by E. lima cells. Rapid hydrolysis of DTX-4 to the diol-ester took place in both cases. Thus, regardless of the route by which DTX-4 is liberated from the cell, either by cell disruption or excretion, the diol-ester will be the dominant form of the toxin to challenge associated organisms. To examine the metabolism of OA diol-ester by T. weissflogii in more detail, serial cultures of the diatom were challenged with OA diol-ester at a concentration of 2.0 ,g·mL,1. The metabolism and fate of the diol-ester in both cellular and medium fractions were monitored over 3 days using liquid chromatography with either ultraviolet (LC-UV) or mass spectrometric (LC-MS) detection. During the course of the experiment, all of the diol-ester was metabolized. LC-MS analysis revealed the presence of multiple oxidative products of OA diol-ester in the medium fraction, including a carboxylic acid derivative. The major metabolites were isolated in sufficient quantity to permit structural elucidation by NMR and MS. All the metabolites identified resulted from oxidation of the diol-ester side chain with the primary sites of attack at the terminal, subterminal, and unsaturated carbons. OA was found in both cellular and medium fractions, and its production was directly correlated with the metabolism of the diol-ester. The relative partitioning of both OA diol-ester and its oxidation products between cells and medium supports the contention that OA diol-ester can readily enter cells, be metabolized, and then excreted in more water-soluble forms. [source]


Micro biochemical engineering to accelerate the design of industrial-scale downstream processes for biopharmaceutical proteins

BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2008
N.J. Titchener-Hooker
Abstract The article examines how a small set of easily implemented micro biochemical engineering procedures combined with regime analysis and bioprocess models can be used to predict industrial scale performance of biopharmaceutical protein downstream processing. This approach has been worked on in many of our studies of individual operations over the last 10 years and allows preliminary evaluation to be conducted much earlier in the development pathway because of lower costs. It then permits the later large scale trials to be more highly focused. This means that the risk of delays during bioprocess development and of product launch are reduced. Here we draw the outcomes of this research together and illustrate its use in a set of typical operations; cell rupture, centrifugation, filtration, precipitation, expanded bed adsorption, chromatography and for common sources, E. coli, two yeasts and mammalian cells (GS-NSO). The general approach to establishing this method for other operations is summarized and new developments outlined. The technique is placed against the background of the scale-down methods that preceded it and complementary ones that are being examined in parallel. The article concludes with a discussion of the advantages and limitations of the micro biochemical engineering approach versus other methods. Biotechnol. Bioeng. 2008;100: 473,487. © 2008 Wiley Periodicals, Inc. [source]