Falling through the cracks: How do policies for alcohol marketing apply to zero alcohol products in Australia?

ISSUES

There is a decline in youth drinking, but also a causal link between alcohol marketing and drinking among young people. Therefore, novel alcohol marketing strategies should be scrutinised, particularly where children are exposed. This includes marketing for zero-alcohol products (ZAP) (containing 0.00% to 1.15% alcohol by volume), which has expanded considerably in recent times. This review examines how the current industry-managed regulatory approach to alcohol marketing applies to ZAPs in Western Australia.

APPROACH

The marketing mix (four Ps of marketing: product, promotion, place, price) was used as a framework to examine federal and state government policies and industry managed codes. Policies were included if they applied to marketing of alcohol products, for example, product labelling, promotion and advertising across various media, the place of purchase and pricing measures (taxation).

KEY FINDINGS

ZAPs were inconsistently defined, meaning that products between 0.05% and 1.15% alcohol by volume were covered under some but not all alcohol policy measures, and application to products under 0.5% alcohol by volume was limited.

IMPLICATIONS

Government policy should more clearly define alcohol marketing and whether ZAPs and other alcohol brand extensions should be treated in the same way as alcoholic products.

CONCLUSION

In Western Australia, the ways in which alcohol policy measures apply to ZAPs are limited and close attention must be paid to how ZAPs may provide additional marketing opportunities for the alcohol industry.

Consumer perceptions of nutrient content claims in Australia: A qualitative study

BACKGROUND

Nutrition and health claims influence consumer purchasing. Claims include content claims, which refer to the amount of a nutrient contained in a product, and health claims, which refer to health benefits of foods or nutrients in a product. Products that display a health claim must meet the Nutrient Profiling Scoring Criterion (NPSC). The present study aimed to explore consumer perceptions of content claims used on food and beverage labelling and advertisements.

METHODS

Semi-structured focus groups were conducted with Australian consumers. Analysis involved an inductive, reflexive approach to thematic analysis.

RESULTS

Six focus groups involving 26 participants were conducted. Four main interconnected themes were generated: (1) complex factors influence food choice; (2) content claim scepticism; (3) the difference between content and health claims is unclear; and (4) the regulation of content claims is not common knowledge. Content claims were used, although generally viewed through a lens of scepticism and mistrust, and seen as a promotional tool for the food industry. Product complexity appeared to increase content claim use as a result of consumer uncertainty of the content of complex products, such as ultraprocessed foods. Most participants were aware that content and health claims were in some way regulated. Overall, they did not know further detail, including the relevant regulatory body.

CONCLUSIONS

For content claims to support the consumer they need to be accurate and their use limited to healthier foods. This can be achieved by requiring products with content claims to meet NPSC thresholds, as required for products making health claims.

Chocolate unicorns and smiling teddy biscuits: analysis of the use of child-directed marketing on the packages of Australian foods

OBJECTIVE

The use of food packaging as a vehicle for marketing to children is under investigated. Our objective was to determine the prevalence and types of child-directed promotional techniques used on food packaging in Australia.

DESIGN

Based on existing literature and regulations, we developed a framework to classify on-pack child-directed promotional techniques involving the use of characters and other elements that appeal to children. We analysed the packaging of all products in eight food categories available for sale from supermarkets in 2019 and recorded the use of child-directed promotions on pack. We assessed the number and proportion of products displaying child-directed promotional techniques overall and assessed the healthiness of products using child-directed promotions against four indicators of healthiness to provide summary data overall and for the manufacturers who most frequently employed child-targeted strategies.

SETTING

Data were collected from the FoodSwitch database in Sydney, Australia.

RESULTS

901/8006 (11·3 %) products displayed one or more child-directed on-pack element. Most frequent was on foods for infants and young children (n 315), confectionery (n 283), snack foods (n 172) and dairy (n 168). Personified characters were the most commonly used element (n 512). Products using child-directed promotional techniques scored poorly on all four indicators of healthiness: mean health star rating 2·34 (out of 5); 81 % ultra-processed and 6·1 % and 4·5 % products eligible to market to children under Western Pacific and Mexican nutrient profiling schemes, respectively.

CONCLUSIONS

Australian children are targeted by promotional techniques on the packaging of unhealthy food products. Stronger regulation of these techniques is warranted to protect children's health.

Exploring the effects of added sugar labels on food purchasing behaviour in Australian parents: An online randomised controlled trial

Background

Evidence of the effects of front-of-pack added sugar labelling remains limited, especially for foods other than sugary drinks. More information is needed about which labels are likely to be most effective in reducing intended purchases of products with higher added sugar content in realistic contexts to inform policymakers’ decisions.

Objective

To determine the impact of added sugar labels on intended purchases of high sugar breakfast cereals, yoghurt, and non-alcoholic beverages.

Methods

Australian parents who were regular purchasers of relevant product categories completed an online parallel randomised controlled trial from 31 August 2020 to 13 February 2021. Participants selected their intended purchase from 10 products in each of packaged beverages, breakfast cereal, and yoghurt categories after randomisation to one of seven added sugar labelling conditions in current use or under consideration by the Australian Government. Logistic regressions assessed differences between intervention and control conditions in the odds of intended purchases of a high sugar product.

Results

2825 eligible participants were randomised with 2582 valid surveys analysed (Control n = 367; ‘Nutrition Information Panel (NIP) with Added Sugar’ n = 364; ‘Teaspoons of Sugar’ n = 369; ‘Warning’ n = 371; ‘Health Star Rating (HSR) using Total Sugar’ n = 368; ‘HSR with Added Sugar’ n = 371; ‘Sugar in the Ingredients List’ n = 372). No consistent effects were found on intended purchases of high sugar products overall or within product categories for any of the tested labels compared to controls (overall, ‘NIP with Added Sugar’: OR 1.00 [95%CI 0.83,1.20]; ‘Teaspoons of Sugar’: 0.94[0.80,1.11]; ‘Warning’: 1.10[0.93,1.30]; ‘HSR with Total Sugar’: 1.01[0.85,1.21]; ‘HSR with Added Sugar’: 1.09[0.92,1.30]; ‘Sugar in the Ingredients List’: 1.01[0.85,1.21]).

Conclusions

Findings reinforce the importance of ensuring nutrition labelling policies are introduced as part of a suite of interventions to influence both consumer and manufacturer behaviour.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12620000858998. Registered 28 August 2020, https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12620000858998.

Local government policies on healthy food promotion and obesity prevention: results from a national Australian survey

OBJECTIVE

Local governments (LGs) often own or manage sport and recreation facilities and can promote health in these settings by implementing healthy food policies. The primary aim of this study was to assess the policies, attitudes and practices of Australian LGs relating to obesity prevention and the provision of healthy food in this setting.

METHODS

In July 2020, all 539 Australian LGs were invited to complete a survey. We assessed LG priorities to obesity prevention, promoting healthy eating and public health as well as the presence of healthy food policies in sporting facilities.

RESULTS

203 (38%) LGs completed the survey. Improving public health was a high priority, while obesity prevention and promoting healthy eating were a medium priority. 22% of LGs reported that the priority given to promoting healthy food had increased over the previous year and stayed the same at 65%. Ten per cent of LGs had a healthy food and drink policy in sporting facilities, with 32% reporting having made changes without a policy. LGs located in major cities, with larger populations and with more facilities reported having made more healthy changes at their facilities.

CONCLUSION

Promoting health is a priority for LGs across Australia, but very few have policies relating to the food environments in their sporting facilities.

IMPLICATIONS FOR PUBLIC HEALTH

Ongoing monitoring is important to assess changes over time and identify LGs where greater support is required.

Implementation and sales impact of a capacity building intervention in Australian sporting facility food outlets: a longitudinal observational study

Background

Few studies have explored behavioural and financial impacts of retail initiatives after 2 years to address the unhealthy food environments common in local government sporting settings.

Aims

To evaluate the impact of a 2-year local government capacity building intervention in sporting facility food outlets on (1) the healthiness of refrigerated drink choices available and visible to customers, (2) healthiness of refrigerated drinks sold and (3) refrigerated drink revenue.

Methods

52 sporting facilities within 8 local governments from Victoria, Australia, participated in an intervention between March 2018 and February 2020 by limiting 'red' (least healthy) drinks to ≤20% of refrigerator display and increasing 'green' (healthiest) drinks to ≥50% of display. Mixed models assessed changes in mean percentage of 'red', 'amber' and 'green' drinks displayed over time, compared with baseline.Facilities provided electronic weekly itemised sales data (December 2015 to February 2020). Weekly volume of 'red' or 'green' drinks sold as a proportion of total drinks sold, and total refrigerated drinks revenue were compared preimplementation and postimplementation using mixed models (seasonal facilities), and mixed-effect interrupted time series models (non-seasonal facilities).

Results

Display of 'red' drinks decreased by mean -17.1 percentage points (pp) (95% CI -23.9 to -10.3) and 'green' drinks increased 16.1 pp (95% CI 9.30, 22.9) between baseline and 18-month audits.At nine seasonal facilities, compared with the summer preimplementation, the mean volume of 'red' drinks sold decreased by -19.0 pp (95% CI -28.6, to -9.51) and refrigerated drink revenue decreased by-AU$81.8 (95% CI -AU$123 to -AU$40.8) per week. At 15 non-seasonal facilities, by February 2020, the volume of 'red' drinks sold decreased on average by -11.0 pp (95% CI -21.6 to -0.41) with no change in drink revenue.

Conclusion

Reducing the display of unhealthy drinks can be an effective public health policy to improve the healthiness of customer purchases, provided there is consideration of potential impacts on revenue.

Policies to restrict unhealthy food and beverage advertising in outdoor spaces and on publicly owned assets: A scoping review of the literature

Unhealthy food marketing influences attitudes, preferences, and consumption of unhealthy foods, leading to excess weight gain. Outdoor advertising is highly visible (often displayed on publicly owned assets), but the evidence supporting regulation is unclear. This systematic scoping review of academic and grey literature aimed to (1) describe potential health and economic impacts of implementing government-led policies that restrict unhealthy food advertising in outdoor spaces or on public assets (including studies examining prevalence of advertising, associations with health outcomes and interventional studies); (2) identify and describe existing policies; and (3) identify factors perceived to have influenced policy implementation. Thirty-six academic studies were eligible for inclusion. Most reported on prevalence of unhealthy food advertising, demonstrating high prevalence around schools and in areas of lower socioeconomic position. None examined health and economic impacts of implemented policies. Four jurisdictions were identified with existing regulations; five had broader marketing or consumer protection policies that captured outdoor food marketing. Facilitators of policy implementation included collaboration, effective partnerships, and strong political leadership. Barriers included lobbying by food, media, and advertising industries. Implementation of food marketing policies in outdoor spaces and on public assets is feasible and warranted. Strong coalitions and leadership will be important to drive the policy agenda forward.

The characteristics and extent of food industry involvement in peer-reviewed research articles from 10 leading nutrition-related journals in 2018

Introduction

There is emerging evidence that food industry involvement in nutrition research may bias research findings and/or research agendas. However, the extent of food industry involvement in nutrition research has not been systematically explored. This study aimed to identify the extent of food industry involvement in peer-reviewed articles from a sample of leading nutrition-related journals, and to examine the extent to which findings from research involving the food industry support industry interests.

Methods

All original research articles published in 2018 in the top 10 most-cited nutrition- and dietetics-related journals were analysed. We evaluated the proportion of articles that disclosed involvement from the food industry, including through author affiliations, funding sources, declarations of interest or other acknowledgments. Principal research findings from articles with food industry involvement, and a random sample of articles without food industry involvement, were categorised according to the extent to which they supported relevant food industry interests.

Results

196/1,461 (13.4%) articles reported food industry involvement. The extent of food industry involvement varied by journal, with The Journal of Nutrition (28.3%) having the highest and Paediatric Obesity (3.8%) having the lowest proportion of industry involvement. Processed food manufacturers were involved in the most articles (77/196, 39.3%). Of articles with food industry involvement, 55.6% reported findings favourable to relevant food industry interests, compared to 9.7% of articles without food industry involvement.

Conclusion

Food industry involvement in peer-reviewed research in leading nutrition-related journals is commonplace. In line with previous literature, this study has shown that a greater proportion of peer-reviewed studies involving the food industry have results that favour relevant food industry interests than peer-reviewed studies without food industry involvement. Given the potential competing interests of the food industry, it is important to explore mechanisms that can safeguard the integrity and public relevance of nutrition research.

Price Promotions by Food Category and Product Healthiness in an Australian Supermarket Chain, 2017-2018

Objectives. To examine the prevalence and magnitude of price promotions in a major Australian supermarket and how they differ between core (healthy) and discretionary (less healthy) food categories.Methods. Weekly online price data (regular retail price, discount price, and promotion type) on 1579 foods were collected for 1 year (April 2017 to April 2018) from the largest Australian supermarket chain. Products audited were classified according to Australian Dietary Guidelines definitions of core and discretionary foods and according to their Health Star Rating (a government-endorsed nutrient profiling scheme).Results. On average, 15.1% (95% confidence interval [CI] = 14.7%, 15.3%) of core foods and 28.8% (95% CI = 28.6%, 29.0%) of discretionary foods were price promoted during a given week. Average discounts were -15.4% (95% CI = -16.4, -14.4) for core products and -25.9% (95% CI = -26.8, -25.1) for discretionary products. The percentage of products on price promotion and the size of the discount were larger for products with a lower Health Star Rating (P < .05).Conclusions. Price promotions were more prevalent and greater in magnitude for discretionary foods than for core foods. Policies to reduce the prevalence and magnitude of price promotions on discretionary foods could improve the healthiness of food purchased from supermarkets.

Diagnostic decision support systems

Diagnostic decision support systems are ready for prime time. We used them in a general medical clinic and found that they could suggest new diagnostic possibilities, focus thinking about clinical problems, and serve as a tool for recertification preparation. In addition, we have found diagnostic decision support systems useful for the novice clinician (fourth-year medical students and interns). These tools serve as a reminder system for learners, suggesting questions to ask the patient, physical exam components to complete, and tests to order. The novice clinician may also use these systems in preparing case presentations. The systems reviewed vary in the ways we described earlier, and there is no one "best buy." Which program is right for you depends on how much detail you want, whether you prefer a CD or internet format, and in what setting you practice. Demos are available from most vendors: Try them out, make a choice, and get on with the business of enhanced diagnostic decision making.

Expression of soluble, recombinant alphavbeta3 integrin fragments in Escherichia coli

No prokaryotic expression of integrin alphavbeta3 has been reported so far. We report here the expression of C-terminally truncated alphavbeta3 receptors in E. coli considering the known features required for dimerization and ligand binding. The expressed protein was insoluble despite of the addition of 'solubilizers' to the culture medium. Osmotic stress conditions combined with added exogenous solutes resulted in a small part of soluble receptor. The alphavbeta3 variants were purified from inclusion bodies or from soluble cytoplasmic maltose binding protein fusions. Heterodimerization of the subunits was proved by immunoprecipitation assays. Receptor-ligand binding was found to depend on the concentration. A competition assay with RGD peptides referred to unspecific receptor-ligand interaction. The latter fact was consistent with the finding that soluble receptors did not bind on RGD peptide-coupled sepharose (GRGDSPK sepharose).

The use of elements of the E. coli Ntr-system for the design of an optimized recombinant expression system for high cell density cultivations

The inducible glnA promoter 2 of the E. coli glutamine synthetase gene is suitable as an expression unit for the production of recombinant proteins at low and high cell densities. It is active when the concentration of ammonium as the sole nitrogen source in the culture medium is below 1 mM. This nitrogen regulatory system was optimized by introduction of expression cassettes consisting of additional elements of the ntr-system. These artificial constructions result in enhanced recombinant gene expression in the production phase. Furthermore, the basic recombinant protein level during the growth phase is reduced due to a tighter promoter control. A three- to four-fold higher accumulation of chloramphenicol-acetyltransferase (as reporter protein) and of anti-EGF-receptor miniantibodies was achieved by increasing the amount of the final regulator molecule NtrC approximately P via plasmidal co-expression of the ntrC gene. The introduction of a modified glnA promoter 1 inverse to glnAp2 lowered the basic activity of glnAp2 to about one half. It is assumed that under nitrogen excess conditions sigma 70-RNA polymerase binds at glnAp1 and thereby prevents most of the binding of sigma 54-RNA polymerase at glnAp2. The optimized expression systems were successfully applied in low and high cell density cultivations. In the fed-batch phase of high cell density cultivations recombinant protein formation was induced through external nitrogen limitation under FIA-controlled concentration of glucose as carbon source.

Co-operative effects of protein engineering and vector optimization on high yield expression of functional bivalent miniantibodies in Escherichia coli

The volumetric yield of functional phosphocholine-binding miniantibodies could be increased in E. coli fermentations by the combination of the following approaches: Firstly, miniantibody mutants with amino acid exchanges in the VH chain leading to improved folding were expressed. Secondly, the expression vector was stabilized by an efficient suicide system to prevent plasmid loss. Thirdly, the cells were grown to high cell densities in a stirred tank reactor.

High-cell-density cultivation of microorganisms

High-cell-density cultivation (HCDC) is required to improve microbial biomass and product formation substantially. An overview of HCDC is given for microorganisms including bacteria, archae and eukarya (yeasts). Problems encountered by HCDC and their possible solutions are discussed. Improvements of strains, different types of bioreactors and cultivation strategies for successful HCDC are described. Stirred-tank reactors with and without cell retention, a dialysis-membrane reactor, a gas-lift reactor and a membrane cyclone reactor used for HCDC are outlined. Recently modified traditional feeding strategies and new ones are included, in particular those for unlimited growth to very dense cultures. Emphasis is placed on robust fermentation control because of the growing industrial interest in this field. Therefore, developments in the application of multivariate statistical control, artificial neural networks, fuzzy control and knowledge-based supervision (expert systems) are summarized. Recent advances using Escherichia coli--the pioneer organism for HCDC--are outlined.

Effect of ppGpp on Escherichia coli cyclopropane fatty acid synthesis is mediated through the RpoS sigma factor (sigmaS)

Strains of Escherichia coli carrying mutations at the relA locus are deficient in cyclopropane fatty acid (CFA) synthesis, a phospholipid modification that occurs as cultures enter stationary phase. RelA protein catalyzes the synthesis of guanosine-3',5'-bisdiphosphate (ppGpp); therefore, ppGpp was a putative direct regulator of CFA synthesis. The nucleotide could act by increasing either the activity or the amount of CFA synthase, the enzyme catalyzing the lipid modification. We report that the effect of RelA on CFA synthesis is indirect. In vitro and in vivo experiments show no direct interaction between ppGpp and CFA synthase activity. The relA effect is due to ppGpp-engendered stimulation of the synthesis of the alternative sigma factor, RpoS, which is required for function of one of the two promoters responsible for expression of CFA synthase.

Expression and secretion of functional miniantibodies McPC603scFvDhlx in cell-wall-less L-form strains of Proteus mirabilis and Escherichia coli: a comparison of the synthesis capacities of L-form strains with an E. coli producer strain

The paper describes the synthesis of the phosphorylcholine-binding miniantibody McPC603scFvDhl x in cell-wall-less L-form strains of Escherichia coli and Proteus mirabilis. Cells of these strains were transformed with the plasmid pACK02scKan, carrying the miniantibody (miniAb) coding sequence under the control of the lac promoter. L-form transformants of both species were able to synthesize the functional miniAb as an extracellular soluble product. The highest quantities were obtained by P. mirabilis L-form strains after induction with 5 mM isopropyl beta-D-thiogalactopyranoside (IPTG). Yields of 45-75 mg/l total antibody protein and of 10-18 mg/l functional miniAb were estimated in the growth medium of shaking cultures 40-80 h after induction with IPTG. About 10% of the active miniAb remained cell-bound. The yields of functional miniAb could be optimized by lowering the growth temperature from 37 degrees C to 26-32 degrees C and by supplementation of the medium with 80 mM sodium fumarate. A comparison of the specific activities revealed that the P. mirabilis L-form strains have a similar synthesis capacity (2-4 mg functional miniAb/g cell dry weight) to that of the producer strain E. coli RV308. The results show that the processes of correct folding and assembling of the miniAb molecules are possible without the periplasmic compartment.

Release of miniantibodies from E. coli cells into the supernatant at low and high cell densities

By chemical permeabilization of E. coli cells with detergents and membrane active peptides considerable amounts of the periplasmic anti-PC-miniantibodies can be released. Releases of active miniantibodies of 31%, respectively of 38%, were obtained by exposing low cell density suspensions to nonionic detergents like Triton X-100 and tetraethyleneglycolmonodecylether. At high cell densities releasing levels of 40% and 56% were observed for these detergents. The addition of cationic, membrane active peptides (PMBN, polylysine 115, magainin II and melittin) led to release of up to 20% of active miniantibodies at low cell densities. The excretion of miniantibodies at low cell densities was increased up to 35% by phospholipase A2. Interestingly, the membrane associating properties of the anti-PC-miniantibodies influenced the permeability of the outer membrane and the excretion of beta-lactamase.

High volumetric yields of functional dimeric miniantibodies in Escherichia coli, using an optimized expression vector and high-cell-density fermentation under non-limited growth conditions

Functional bivalent miniantibodies, directed against the epidermal growth factor receptor, accumulated to more than 3 gl-1 in high-cell-density cultures of Escherichia coli RV308(pHKK) on a pilot scale. The miniantibodies consist of scFv fragments with a C-terminal hinge followed by a helix-turn-helix motif, which homodimerizes in vivo. The improved expression vector pHKK is characterized by the hoklsok suicide system, improving plasmid maintenance, and the inducible lac pl o promoter system with the very strong T7g10 Shine-Dalgarno sequence. The expression unit is flanked by terminators. The prototrophic RV308 cells were cultivated in glucose mineral salt medium and reached a cell density of 145 g dry biomass l-1 after 33 h. After induction, growth continued almost unchanged for a further 4 h with concomitant miniantibody formation. In the fedbatch phase, the concentration of glucose was kept almost constant at the physiological level of approximately 1.5 gl-1, using on-line flow injection analysis for control. Surprisingly, E. coli RV308(pHKK) did not accumulate significant amounts of the metabolic by-product acetate under these unlimited aerobic growth conditions.

Influence of phospholipid composition on excretion of beta-lactamase from a stringent/relaxed Escherichia coli K 12 strain pair

In comparison to stringent (relA+) controlled Escherichia coli cells, relaxed (relA) controlled E. coli cells excreted more recombinant beta-lactamase into the culture medium. The analysis of the composition of phospholipid fractions of the cells yielded increased levels of phosphatidylserine in relaxed controlled cells. We added various phospholipid vesicles to growing cells in order to influence the excretion rate via their incorporation in the membranes. The addition of vesicles to phosphatidic acid, phosphatidylglycerol and phosphatidylserine reduced the excretion of beta-lactamase whereas vesicles of phosphatidylethanolamine and phosphatidylcholine decreased or increased the excretion of beta-lactamase in dependence on the individual fatty acid residues of the added phospholipids. The lower the degree of saturation of the added phospholipids the more permeable was the cell envelope for beta-lactamase.

Formation of recombinant proteins in Escherichia coli under control of a nitrogen regulated promoter at low and high cell densities

The use of a modified Escherichia coli glnAP2 promoter results in the formation of both homologous and heterologous, cytoplasmic and periplasmic recombinant proteins in a nitrogen concentration dependent manner. As in the E. coli nitrogen regulatory system, glnAP2 controlled gene expression is induced when ammonium concentration in the growth medium is below 1 mM (nitrogen limitation), otherwise only extremely low expression of recombinant genes is observed. Both high cell density cultivations (HCDC) and low cell density cultivations (LCDC) gave similar results for inducibility and formation of the following recombinant proteins: chloramphenicol-acetyltransferase, phosphorylcholine binding mini-antibodies (scFv-dhlx of McPC603) and K1-streptokinase. Recombinant proteins were formed in quantities of about 2-3% of total cellular protein. At low cell densities, slightly higher quantities resulted under partial nitrogen limitations than under total nitrogen limitation. In contrast, high cell density cultivations resulted in lower product concentrations at partial nitrogen limitation compared with total nitrogen limitation. These lowered product concentrations were probably due to the very high amounts of K+ or Na+ ions which accumulated during pH-regulation, thereby disturbing growth. HCDC under partial nitrogen limitation decreased proteolysis of recombinant proteins, therefore reduced amounts of proteases are considered to be responsible.

The appearance of cytoplasmic membranes of Escherichia coli cells in freeze-fracture electron microscopy after stringent and relaxed response

Guanosine-5'-diphosphate-3'-diphosphate (ppGpp), an effector for many metabolic pathways, is synthesized by the relA gene product after amino acid limitation. Studies of stringent controlled Escherichia coli CP78 (relA+) and relaxed controlled E. coli CP79 (relA-) were carried out to test whether these strains differ in the appearance of their cytoplasmic membranes after induction of stringent and relaxed response. Cytoplasmic membrane structures of the cells were investigated by freeze-fracture electron microscopy after cooling the cells. The obtained micrographs showed a net-like distribution of the particles in the cytoplasmic membranes of relaxed controlled cells whereas such a pattern was not detectable in the stringent controlled counterparts.

Influence of stringent and relaxed response on excretion of recombinant proteins and fatty acid composition in Escherichia coli

In contrast to stringent (relA+) cells of Escherichia coli, relaxed (relA) cells excreted recombinant proteins (beta-lactamase, interferon alpha 1) into the culture medium during amino acid limitation. Comparative analyses of overall fatty acid composition in relA+ cells and relA cells were performed and revealed that, in wild-type cells, drastic alterations occurred during the stringent response. The portion of saturated fatty acids (C16:0) and the fractions of cyclopropane fatty acids (C17cyc and C19cyc) increased whereas the portions of unsaturated fatty acids (C16:1 and C18:1) decreased. In cells of the relaxed mutant, no significant changes in the overall composition of the fatty acids were observed after the onset of amino acid limitation. These results indicate that a change in fatty acid composition of membrane lipids after starvation of cells may be responsible for the prevention of loss of cellular proteins into the culture medium in stringent controlled cells of Escherichia coli.

Improved bivalent miniantibodies, with identical avidity as whole antibodies, produced by high cell density fermentation of Escherichia coli

The combination of single-chain Fv-fragments (scFv) with a C-terminal, flexible linking region followed by a designed or natural dimerization domain provides a versatile system for targeted association of functional fragments in the periplasmic space of Escherichia coli. For homodimerization in vivo, two scFv fragments with a C-terminal hinge followed by a helix-turn-helix motif form "miniantibodies" with significantly higher avidity than in the case of leucine zipper containing constructs. The favorable design probably results in an antiparallel four-helix bundle and brings the homodimer to the same avidity as the whole IgA antibody, from which the binding site was taken. The molecular weight of the bivalent miniantibody is almost the same as that of a monovalent Fab fragment. We report here a high-cell density fermentation of E. coli producing these miniantibodies and a work-up procedure suitable for large scale production. Without any need of subsequent chemical coupling in vitro, approximately 200 mg/l of functional dimeric miniantibodies can be directly obtained from the E. coli culture.

High-cell-density cultivation of Escherichia coli

High-cell-density cultivations of Escherichia coli in glucose-mineral-salt media produce more than 100 g dry cells litre-1 in special fed-batch modes with feeding of glucose and ammonia only. The specific growth rate can be adjusted to allow optimum recombinant protein generation.

Improvement of recombinant gene expression in Escherichia coli for glucose-controlled continuous and fed-batch cultures

Escherichia coli TG1 (pHRW500) permanently expressed the human interferon alpha 1 gene (ifn alpha 1) directed by the tryptophan promoter (trpP.O) during continuous and fed-batch cultivation with a limited supply of glucose. The expression of ifn alpha 1 could be improved after insertion of the catabolite activator region (cap) upstream to trpP.O during cultivation of the modified E. coli TG1(pHRW500cap) in glucose-controlled continuous and fed-batch cultures. The cap-mediated stimulatory effect on the expression of cap-trpP.O-ifn alpha 1 increased with decreasing dilution rate. These results are in line with the increase in the level of cAMP with declining dilution rate and the well-known positive effects of cAMP-catabolite gene activator protein (CAP) at the transcriptional level. In addition, expression of the galactokinase gene (trpP.O-galK) in E. coli TG1(pDR720) could be improved in the same way with cap-trpP.O-galK in E. coli TG1(pDR720cap). Determinations of plasmid copy numbers, cellular amounts of galactokinase-mRNA, activity of galactokinase (AGalK) and the concentration of galactokinase at various dilution rates (D) strengthen the conclusion that the increase in AGalK with decreasing D was indeed due to the cap-mediated enhancement of transcription of the galK gene. We suggest that expression of other recombinant genes directed by various promoters that allow permanent transcription during growth with limited glucose supply in chemostat and fed-batch fermentors can be improved by appropriate insertion of the cap region.

High cell density fermentation of recombinant Escherichia coli with computer-controlled optimal growth rate

In recent years recombinant DNA technology has enabled us to produce various proteins of therapeutic importance with microorganisms. As an appropriate host organism, E. coli plays a dominant role. Yields of E. coli dry cell mass in shaker flask culture range from 1-2 g/L, whereas in fermentors up to 10 g dry cells/L can be achieved. ZIMET and GBF have developed a high cell density fermentation process that produces E. coli (on a glucose/mineral salt medium) up to more than 100 g dry cells/L in a special fed-batch mode. This cultivation strategy prevents oxygen limitation and hence the accumulation of acetate and other metabolic byproducts. The specific growth rate can be adjusted so that product formation reaches its optimum value. An example of the production of alpha1-interferon is presented. The high cell density fermentations were realized in 30- and 450-L Chemap fermentors (ZIMET) and in a three-stage bioreactor scale-up system (72, 300, and 1,500 L) developed in cooperation with GBF and B. Braun Melsungen AG. Multiloop controllers were used to control the process variables.

High cell density cultivation of Escherichia coli at controlled specific growth rate

A high cell density cultivation (HCDC) for growth of Escherichia coli in an especially designed glucose/mineral salt medium is proposed. The HCDC essentially starts as a batch process which is followed by a two-phase fed-batch cultivation. After unlimited growth at mu max = 0.45 h-1 in the batch part, growth was controlled at a reduced specific growth rate (mu = 0.11 h-1 less than mu max) over a period of 3 doubling times in which the biomass concentration increased from 12 to 95 g 1(-1) (phase 1 of fed-batch cultivation). Control of growth (mu) was realized by a PO2 control loop (by variation of glucose feeding) and a mu control loop (by variation of agitation speed N) while the actual mu was calculated from the off-gas composition. If the agitation rate cannot be increased anymore the mu controller is switched off (end of phase 1). In the following phase 2, mu declines, however, the still acting pO2 (glucose) controller guarantees sufficient O2 supply till the end of the cultivation with a biomass concentration of 110 g 1(-1) (dry mass). The proposed HCDC suppresses generation of inhibitory by-products and the high yield coefficients indicate the economy of the process.

High cell density fermentation of recombinant Escherichia coli expressing human interferon alpha 1

A defined medium was developed which, by means of a specific fed-batch mode, allows growth of the recombinant Escherichia coli strain TG1 (pBB210) up to a cell density of 60 g dry weight/l. Apart from glucose and aqueous ammonia fed as carbon and nitrogen sources, it was necessary to supply other nutrients or O2-enriched air. Aqueous ammonia also served for pH control. The pO2 level was kept at 20% saturation via closed-loop controls operating the two output variables of stirrer speed and glucose feeding rate. This fed-batch method prevented significant accumulation of acetate and other metabolic by-products. The recombinant E. coli expressed interferon alpha 1 more efficiently at a lower specific growth rate (muPr approximately 0.15 h-1) than at the maximum specific growth rate (mu max = 0.45 h-1). Therefore, fermentation in the batch phase at mu max was only allowed to continue up to a medium cell density. In the succeeding fed-batch phase, the specific growth rate was reduced to muPr by increasing the stirrer speed according to an empirically developed time scale.

Synergistic effect of cobalt on the induction by A-factor of the formation of aerial mycelium and anthracyclines by a blocked mutant of Streptomyces griseus

Cobalt ions synergistically supported the inducing effect of A-factor 1a on the formation of aerial mycelium and anthracyclines by the blocked S. griseus mutant 86. This suggested an involvement of effector 1a in the transport or metabolism of this trace element. In accordance with the proposed role of 1a as an autoregulatory secondary metabolite, the parent strain S. griseus JA 3933 secreted 1a into the medium after a decrease of the specific growth rate and before the onset of antibiotic production.