Continuous bioprocessing: The real thing this time?: 10th Annual bioProcessUK Conference,December 3–4, 2013, London,UK

The Annual bioProcessUK Conference has acted as the key networking event for bioprocess scientists and engineers in the UK for the past 10 years. The following article is a report from the sessions that focused on continuous bioprocessing during the 10^th Annual bioProcessUK Conference (London, December 2013). These sessions were organized by the ‘EPSRC Centre for Innovative Manufacturing in Emergent Macromolecular Therapies’ hosted at University College London. A plenary lecture and workshop provided a forum for participants to debate topical issues in roundtable discussions with industry and academic experts from institutions such as Genzyme, Janssen, Novo Nordisk, Pfizer, Merck, GE Healthcare and University College London. The aim of these particular sessions was to understand better the challenges and opportunities for continuous bioprocessing in the bioprocessing sector.     

Biologic-response-modifier-induced indoleamine 2,3-dioxygenase activity in human peripheral blood mononuclear cell cultures

Degradation of tryptophan to kynurenine, catalyzed by indoleamine 2,3-dioxygenase (IDO), has been augmented in human epithelial cell lines treated with human interferon-gamma (HuIFN-gamma). Several human biologic response modifiers, including HuIFN-gamma, HuIFN-beta, HuIFN-alpha, interleukin 2 (HuIL-2), and tumor necrosis factor alpha, have now been assessed for their ability to enhance tryptophan degradation in human peripheral blood mononuclear cell (PMC) cultures. PMC were isolated from normal donors, cultivated in RPMI 1640 medium containing [3H]tryptophan, and treated with individual biologic response modifiers. At various intervals, culture supernatants were removed, fractionated by reversed-phase high performance liquid chromatography, and radioactivity in resultant fractions was determined. Significantly increased amounts of tryptophan catabolites were observed after treatment with HuIFN-gamma, HuIFN-beta, HuIFN-alpha, and HuIL-2, but not human tumor necrosis factor alpha. Often, greater than 30% of available tryptophan was degraded by treated PMC cultures. Although antibodies to HuIFN-alpha, HuIFN-beta, and HuIFN-gamma specifically neutralized the induction of IDO activity in PMC by their respective HuIFN, only anti-HuIFN-gamma antibody also neutralized HuIL-2-induced IDO activity. Furthermore, T24 bladder carcinoma cells, in which IDO was induced by HuIFN-gamma but not by the other biologic response modifiers, were induced to degrade tryptophan by supernatants of HuIL-2-stimulated PMC cultures, but not by HuIFN-beta-stimulated PMC culture supernatants. Thus, whereas HuIL-2 indirectly induced IDO in PMC cultures by stimulating production of HuIFN-gamma, all cases of interferons appeared to induce IDO directly in PMC cultures.     

Ecology of heath communities dominated by Cassiope tetragona at Alexandra Fiord, Ellesmere Island, Canada

At a high arctic lowland on Ellesmere Island, heath communities dominated by Cassiope tetragona were widespread, and occurred in a variety of habitats that differred in time of snowmelt, relative site moisture, soil thaw depth, and air and soil temperature. Cover, standing crop, and production were dominated by woody plants, notably Cassiope tetragona and Dryas integrifolia . The Cassiope -dominated heaths were similar in composition to those at other Canadian high arctic localities, but were less similar to localities in Greenland and Spitzbergen. Compositional relationships among Cassiope -dominated heaths in different habitats at the study site may be largely determined by two interrelated environmental factors, time of snowmelt and site moisture.
Aboveground vascular plant biomass was concentrated near the ground surface, resulting in simple vertical structure that takes advantage of relatively warm soil and air temperatures in summer, and a protective snow cover in winter. Aboveground vascular plant standing crop was largely comprised of attached dead tissue, and there were equal proportions of above- and belowground biomass. Low community production was due to dominance by long-lived, slow-growing species, and to short growing seasons and cold temperatures. Overall character of Cassiope -dominated heaths reflects the conservative, stress tolerant growth strategy of the dominant species, Cassiope tetragona .     

Retrovirus-mediated transfer of an adenovirus gene encoding an integral membrane protein is sufficient to down regulate the receptor for epidermal growth factor.

We have used retrovirus-mediated gene transfer to introduce sequences encoding a 10,400-molecular-weight (10.4K) adenovirus protein previously shown to down regulate the receptor for epidermal growth factor (EGF) into two murine cell lines that possess human EGF receptors (EGF-Rs). Assays for receptor expression showed that acute infection resulted in rapid, constitutive down regulation of the EGF-R via a pathway that appears to be endosome mediated. This represents the first demonstration that 10.4K expression in the absence of other virus-encoded proteins is sufficient to elicit this response. The usefulness of this approach for the study of 10.4K-mediated signal transduction in cells with a nontransformed phenotype is discussed.     

Ferricrocin functions as the main intracellular iron-storage compound in mycelia ofNeurospora crassa

Summary Neurospora crassa produces several structurally distinct siderophores: coprogen, ferricrocin, ferrichrome C and some minor unknown compounds. Under conditions of iron starvation, desferricoprogen is the major extracellular siderophore whereas desferriferricrocin and desferriferrichrome C are predominantly found intracellularly. Mössbauer spectroscopic analyses revealed that coprogen-bound iron is rapidly released after uptake in mycelia of the wild-typeN.crassa 74A. The major intracellular target of iron distribution is desferriferricrocin. No ferritin-like iron pools could be detected. Ferricrocin functions as the main intracellular iron-storage peptide in mycelia ofN. crassa. After uptake of ferricrocin in both the wild-typeN. crassa 74A and the siderophore-free mutantN. crassa arg-5 ota aga, surprisingly little metabolization (11%) could be observed. Since ferricrocin is the main iron-storage compound in spores ofN. crassa, we suggest that ferricrocin is stored in mycelia for inclusion into conidiospores.