Posts Tagged ‘Food’

Potential industrial biotechnology with cyanobacteria and eukaryotic microalgae

Monday, May 27th, 2013

Putting algae to work Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. Cyanobacteria are promising host organisms for the production of small molecules that can be secreted such as ethanol, butanol, fatty acids and other organic acids. Eukaryotic microalgae are interesting for products for which cellular storage is important such as proteins, lipids, starch and alkanes.

For the development of new and promising lines of production, strains of both cyanobacteria and eukaryotic microalgae have to be improved. Transformation systems are much better developed in cyanobacteria. However, several products would be preferably produced with eukaryotic microalgae. In the case of cyanobacteria a synthetic-systems biology approach has a great potential to exploit cyanobacteria as cell factories. For eukaryotic microalgae transformation systems need to be further developed. A promising strategy is transformation of heterologous (prokaryotic and eukaryotic) genes in established eukaryotic hosts such as Chlamydomonas reinhardtii.

Experimental outdoor pilots under containment for the production of genetically modified cyanobacteria and microalgae are in progress. For full scale production risks of release of genetically modified organisms need to be assessed. This review article summarizes potential and current biotechnological developments.

 

Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae. Curr Opin Biotechnol. 03 May 2013. pii: S0958-1669(13)00085-2. doi: 10.1016/j.copbio.2013.04.004
Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments. Cyanobacteria are promising host organisms for the production of small molecules that can be secreted such as ethanol, butanol, fatty acids and other organic acids. Eukaryotic microalgae are interesting for products for which cellular storage is important such as proteins, lipids, starch and alkanes. For the development of new and promising lines of production, strains of both cyanobacteria and eukaryotic microalgae have to be improved. Transformation systems have been much better developed in cyanobacteria. However, several products would be preferably produced with eukaryotic microalgae. In the case of cyanobacteria a synthetic-systems biology approach has a great potential to exploit cyanobacteria as cell factories. For eukaryotic microalgae transformation systems need to be further developed. A promising strategy is transformation of heterologous (prokaryotic and eukaryotic) genes in established eukaryotic hosts such as Chlamydomonas reinhardtii. Experimental outdoor pilots under containment for the production of genetically modified cyanobacteria and microalgae are in progress. For full scale production risks of release of genetically modified organisms need to be assessed.

 

The end of BSE

Tuesday, February 15th, 2011

cow The BSE epidemic cost us billions, and devastated the British farming industry. Now, that plague is at an end. Overall, as many as three million animals were infected; in the peak year, 1992, the UK saw 37,280 diagnoses. Yet there are good reasons why any celebrations have been put on hold. All told, around half a million infected animals entered the food chain. Although it remains unclear how many people ate the most infectious parts, it is clear that the majority of the British population was exposed. So far, the human equivalent of BSE, variant Creutzfeldt-Jakob disease (vCJD), has claimed 170 lives, mainly through consumption of BSE-infected beef. And because of the extraordinary incubation time of the disease, it is possible that many more cases may be waiting in the wings.

Read more: The end of BSE

Bacteriophages as biocontrol agents

Monday, December 6th, 2010

Bacteriophages as biocontrol agents Bacteriophages represent one of the most abundant biological entities in nature and have long been recognized for their potential use as therapeutic agents. In recent years overprescription of antibiotics and the concomitant development of antibiotic-resistant ‘super-bugs’ have highlighted the need for alternative strategies to combat infectious diseases. Consequently, a lot of phage research in the past two decades was aimed at assessing whether phage can be used to eliminate undesirable bacteria. Traceability is a requirement in modern food production, incorporating every step in the production process, commonly known as the ‘farm to fork’ concept (European Commission White paper on Food Safety, January 2000). Phages are omnipresent and are accidentally, yet regularly, consumed through ingestion of water and food. For this reason they are presumed to be safe as undesirable effects have not been reported. This, together with their specificity, makes them excellent tools for food safety purposes.

The ‘farm to fork’ concept identifies quality assurance steps at which bacterial contamination may occur, and which also represent critical points where phage treatments may be applied. The most frequently encountered food pathogens belong to one of the four dominant genera, Salmonella, enterotoxigenic Escherichia coli, Campylobacter and Listeria, along with less common infections by Clostridium spp., Staphylococcus aureus, Streptococcus suis and Cronobacter sakazakii. Phages targeting strains of each of these species have been identified and this review discusses the pros and cons of the use of phages as biocontrol, biosanitation and detection agents.

Bacteriophages as biocontrol agents of food pathogens. Curr Opin Biotechnol. Nov 4 2010
Bacteriophages have long been recognized for their potential as biotherapeutic agents. The recent approval for the use of phages of Listeria monocytogenes for food safety purposes has increased the impetus of phage research to uncover phage-mediated applications with activity against other food pathogens. Areas of emerging and growing significance, such as predictive modelling and genomics, have shown their potential and impact on the development of new technologies to combat food pathogens. This review will highlight recent advances in the research of phages that target food pathogens and that promote their use in biosanitation, while it will also discuss its limitations.

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You Are Not What You Eat

Wednesday, November 17th, 2010

These are the bacteria that live in your gut The types of gut bacteria that populate the guts of primates depend on the species of the host as well as where the host lives and what they eat. A new study examines the gut microbial communities in great apes, showing that a host’s species, rather than their diet, has the greatest effect on gut bacteria diversity.

Bacteria are crucial to human health. They enhance the immune system, protect against toxins, and assist in the maturation and renewal of intestinal cells. Gut microbes outnumber our own cells by 10 to 1 but little is known about how certain species come to populate our stomachs, which are sterile at birth. What causes this variation within microbial communities has been a matter of debate. Some scientists have argued that diet and habitat play the most prominent roles. The new research finds that diversity in the composition of these gut communities, not including those occasional transients and unwelcome visitors such as pathogenic bacteria, depends primarily upon the host species.

Using genetic markers, the researchers measured the diversity and abundance of various microbial species found in fecal matter of five great ape species collected in their native ranges and discovered that bacterial populations assorted to species. Moreover, the relationships of the microbial communities matched that of their host. In other words, not only is it possible to differentiate chimpanzees from humans by examining the microbial populations within their guts, but these gut microbes have been tracking the evolution of their hosts for millions of years.

Evolutionary Relationships of Wild Hominids Recapitulated by Gut Microbial Communities. (2010) PLoS Biol 8(11): e1000546. doi:10.1371/journal.pbio.1000546
Multiple factors over the lifetime of an individual, including diet, geography, and physiologic state, will influence the microbial communities within the primate gut. To determine the source of variation in the composition of the microbiota within and among species, we investigated the distal gut microbial communities harbored by great apes, as present in fecal samples recovered within their native ranges. We found that the branching order of host-species phylogenies based on the composition of these microbial communities is completely congruent with the known relationships of the hosts. Although the gut is initially and continuously seeded by bacteria that are acquired from external sources, we establish that over evolutionary timescales, the composition of the gut microbiota among great ape species is phylogenetically conserved and has diverged in a manner consistent with vertical inheritance.

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Are your tomatos looking dodgy?

Monday, November 8th, 2010

Tomato yellow leaf curl Tomato yellow leaf curl virus (TYLCV) poses a serious threat to tomato production throughout the temperate regions of the world. A new analysis suggests that the virus probably arose somewhere in the Middle East between the 1930s and 1950s and that its global spread only began in the 1980s after the emergence of two strains – TYLCV-Mld and -IL. In agreement with other work, it finds that the highly invasive TYLCV-IL strain has jumped at least twice to the Americas – once from the Mediterranean basin in the early 1990s and once from Asia in the early 2000s. Although the results corroborate historical accounts of TYLCV-like symptoms in tomato crops in the Jordan Valley in the late 1920s, they indicate that the region around Iran is both the current center of TYLCV diversity and is the site where the most intensive ongoing TYLCV evolution is taking place. The analysis indicates that this region is epidemiologically isolated suggesting that novel TYLCV variants found there are probably not direct global threats, and identifies the Mediterranean basin as the main launch-pad of global TYLCV movements.

The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World. (2010) PLoS Pathog 6(10): e1001164. doi:10.1371/journal.ppat.1001164
The ongoing global spread of Tomato yellow leaf curl virus (TYLCV; Genus Begomovirus, Family Geminiviridae) represents a serious looming threat to tomato production in all temperate parts of the world. Whereas determining where and when TYLCV movements have occurred could help curtail its spread and prevent future movements of related viruses, determining the consequences of past TYLCV movements could reveal the ecological and economic risks associated with similar viral invasions. Towards this end we applied Bayesian phylogeographic inference and recombination analyses to available TYLCV sequences (including those of 15 new Iranian full TYLCV genomes) and reconstructed a plausible history of TYLCV’s diversification and movements throughout the world. In agreement with historical accounts, our results suggest that the first TYLCVs most probably arose somewhere in the Middle East between the 1930s and 1950s (with 95% highest probability density intervals 1905–1972) and that the global spread of TYLCV only began in the 1980s after the evolution of the TYLCV-Mld and -IL strains. Despite the global distribution of TYLCV we found no convincing evidence anywhere other than the Middle East and the Western Mediterranean of epidemiologically relevant TYLCV variants arising through recombination. Although the region around Iran is both the center of present day TYLCV diversity and the site of the most intensive ongoing TYLCV evolution, the evidence indicates that the region is epidemiologically isolated, which suggests that novel TYLCV variants found there are probably not direct global threats. We instead identify the Mediterranean basin as the main launch-pad of global TYLCV movements.

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Beware the buffet

Wednesday, August 18th, 2010

Screenshot Even if we have never succumbed to it, we are all familiar with the sickness caused by noroviruses due to high-profile media coverage of outbreaks in various closed communities, such as hospitals and cruise ships. In this article in Microbiology Today, Ian Goodfellow and David Brown ask, how extensive are noroviruses in our food chain and what can be done to prevent outbreaks in future?

In the catering industry, education of food handlers is key. Clear guidelines for good practice in food preparation need to be strictly adhered to and policed. Whilst it is generally accepted that there remains an ongoing risk from oysters, etc, since sewage contamination of estuarine waters is likely to continue and depuration is ineffective for viruses, the development of sensitive screening procedures for identifying contamination has the potential to reduce the risk. Further improvements in decontamination of contaminated food and environmental settings will undoubtedly aid in minimizing the effects of norovirus contamination and outbreaks. Until such times that vaccines and/or antivirals are available, as consumers, good hygiene and common sense are the most effective protection against norovirus infection, i.e. increased hand washing, as well as avoidance of shared food sources/ utensils and pre-prepared food during outbreaks.

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Food security and microbiology

Wednesday, August 11th, 2010

Potato blight As the human population continues to grow, ever greater demands are placed on food production. In this article in Microbiology Today, Monica Winstanley and Celia Caulcott ask, what contribution can microbiologists make to ensure that the supply of food to all people is secure in this uncertain and changing world?

Around 800 million people lack food security, which means they do not have adequate access to safe and nutritious food. The global population is expected to exceed 9 billion by 2050, and demand for food is likely to increase further because of growing affluence and urbanization, climate change and competition for land. Research can make a unique contribution to averting a potentially greater crisis: by increasing yields and reducing losses in crop and livestock production; by optimizing food processing, manufacture and distribution; by reducing waste and losses due to spoilage; and by understanding and addressing economic and social factors that shape consumers’ needs.

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All you can eat?

Wednesday, August 4th, 2010

Screenshot The UK is not self-sufficient in food production, and we are completely reliant on imported food to feed the nation. In this article in Microbiology Today, Niamh Murphy asks, how can we be sure that the food we import is safe for human consumption?

The food chain is global; ingredients used to produce a simple home cooked meal are often sourced worldwide, but this is not a new phenomenon in the UK. British store cupboards have benefited from imported food since the discovery of the new world and the introduction of potatoes into the diet in the 16th century. Extensive trade networks set up in the 17th and 18th centuries brought spices and tea from India and China, with further foods to follow. Global trade supports farmers and the worldwide economy. The global market allows alternative sources of food to be found to ensure a constant, year-round supply. Importing food has provided consumers in the UK with a cheap, plentiful and wide range of foods, although the negative effects on the environment due to transportation of foods over hundreds or thousands of miles (food miles) has raised concerns over the necessity of importing out-of season or exotic foods purely for choice.

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How bacterial plant pathogens escape their fate

Wednesday, July 28th, 2010

Screenshot The immune system of plants can be unstable in the face of rapidly evolving micro-organisms, and pathogens that can evade recognition can spread with alarming speed through a plant population. In this article in Microbiology Today, Gail Preston and Dawn Arnold ask, what is the reason for this inherent instability, and how can disease control be improved?

Plants, unlike animals, lack an adaptive immune system that allows them to recognize and defend against novel pathogenic micro-organisms. Instead they rely on a heritable, innate immune system in which plant receptors recognize the presence or activity of microbial molecules known as elicitors. Plants exposed to infection can increase the effectiveness of their immune system by increasing the speed and strength of their defence mechanisms. However, pathogens that have the ability to evade recognition can spread rapidly through plant populations. The instability of receptor-dependent resistance in the face of rapid microbial evolution creates one of the most fundamental challenges in plant breeding. In this article we discuss why receptordependent resistance breaks down in the face of pathogen evolution and consider whether knowledge of pathogen evolution can provide insights to improve disease control.

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