SNIPPETS

www.saafost.org.za
Volume 21. Number 6. 2016
013-075NPO


Public Acceptance of Food Products from Genome-Edited Crops

Genome editing techniques, such as CRISPR/Cas9 system, can achieve transgene-free gene modifications and is expected to generate a wide range of plants. However, the public perception against GMOs suggests that people will initially be hesitant to accept these plants.

Tetsuya Ishii and Motoko Araki from Hokkaido University in Japan explored the bottlenecks of consumer acceptance of transgene-free food crops developed through genome editing and made recommendations. People should not pursue a zero-risk bias regarding such crops. Developers should also aim to produce cultivars with traits that would satisfy consumer needs, aside from those for farmers only.

Moreover, developers must also investigate off-target mutations in resultant plants and initially refrain from multiplex genome editing. In terms of regulation, the government should consider their status and establish appropriate regulations. The government should also promote communication between the public and developers.

If people are knowledgeable of the benefits of genome-edited plants and trust in the regulations, then transgene-free crops could gradually be integrated into our society.

For more on this study, read the article in Plant Cell Reports. Crop Biotech Update 1 Dec. 2016.

Eat your fibre or face the flesh-eating microbe cannibals

�Eat your bran even if it tastes horrible � its good for you!� Many of us remember this advice from decades ago. While fibre has been a good cure as a bulking agent for exciting disorders like constipation, it has a dull image and has faded into the background behind trendier (and more commercial) food messages like gluten, cholesterol, saturated fat and sugar. Often it can be the hardest item to find on the food label. (But fibre�s fortunes may now be on the turn. New research in the journal Cell sheds light on how fibre works to protect the gut. Ed)

An international team used special mice born and raised in sterile conditions with no gut microbes of their own. Normally, all animals from birth have a massive microbe community living mainly in the lower intestine (colon). In humans, this reaches 100 trillion microbes � outnumbering our own cells.

These microbes (mainly bacteria but also viruses and fungi) have co-evolved with us and produce many of our vitamins, hormones and chemicals. They are also key to regulating our immune systems, weight and mood. Abnormalities have been linked to many disorders. Humans have around 17 digestive enzymes and microbes have thousands � the primary role of microbes is digesting high fibre foods (that we can�t) to extract the key nutrients.

In the experiment, the sterile mice received a transplant of 14 well-known bacteria that normally grow in the human gut. They were then starved of fibre, which led the microbes to change their normal eating habits and instead feed on the natural layer of mucus (made up of tasty carbs) that lines the gut. This would be fine for short periods of time, when the body has time to regenerate the layer, but when it is prolonged � as in people on long-term junk food diets � the mucus layer becomes dangerously thin.

The new study showed that when the mucus layer is thinner because of a lack of fibre the gut is much more susceptible to infections. Microbes more easily cross the gut wall into the blood stream. As well as infections this also causes irritation and inflammation of the colon � called colitis. This is believed to be the basis of many common modern gut problems. The team tried to rectify the problem by feeding the mice with prebiotics. They found that while real unprocessed fibre did the trick, when the mice were fed processed, supplement fibre, like inulin powder, it didn�t work nearly as well.
https://theconversation.com/eat-your-fibre-or-face-the-flesh-eating-microbe-cannibals-69126. November 22, 2016

New study: Salmonella thrives in salad bags

Research is showing that green leafy salads containing lettuce and spinach are subject to colonisation by food poisoning bacteria, most frequently Salmonella, E. coli and Listeria. In 2014, beansprouts contaminated with Salmonella infected more than 100 people in the US, a quarter of whom were hospitalised. In February 2016, more than 50 people in Victoria, Australia developed salmonellosis after eating bagged salad leaves, while in July 2016, 161 people fell ill in the UK after eating mixed salad leaves and two people died. The EU league table of sources of food poisoning outbreaks now ranks green salads as the second most common source of food-borne illness.

Our project does not indicate any increased risk to eating leafy salads, but it does provide a better understanding of the factors contributing to salad-associated food poisoning risks and highlights the need for continued good practice in salad leaf production and preparation. Public Health England advises thorough washing of all salad leaves and other soil grown vegetables.

With regards to eating leafy salads, which are a nutritious part of the diet, they should be stored, prepared and used according to the guidance on the pack � including refrigeration and use-by instructions. Avoid bags of salad with mushed up leaves, avoid any bags or salad containers that look swollen, store in the fridge and use the salad as quickly as possible after purchase to minimise the growth of any pathogens that might be present.

It is not at all likely that you will become ill from eating salads, but they are consumed raw and so vigilance is needed.

https://theconversation.com/new-study-salmonella-thrives-in-salad-bags-68863

Genome Sequence of 5,310-Year-Old Maize Cob Provides Insights on Its Early Domestication

Researchers from the Natural History Museum of Denmark published a study of a 5,310-year-old maize cob from the Tehuacan Valley of Mexico, providing new insights into the early stages of maize domestication.

In the gene-by-gene analysis, the ancient sample shows many key genes had already been modified through human selection, including the lack of a hard seed coat and changes in flowering time. Archaeological evidence suggests that 5,000 years ago, people who planted and consumed maize likely lived in small groups of people from extended families, which explains why the ancient Tehuacan Valley maize is morphologically and genetically so distinct from modern corn.

Jazm�n Ramos Madrigal, one of the authors of the study said that these ancient people moved seasonally and mostly consumed wild plants and animals, supplementing their diets with some domesticated plants. It was only during later periods with higher populations and socially stratified societies that maize became a staple. She cites the Olmecs (~1200 BC) and the Maya (200BC � 1000 AD), who required reliable and predictable food sources to support their cities, and it was at that point that maize would have undergone further selection for important traits. Crop Biotech Update. 23 Nov 2016.

For more details, visit the University of Copenhagen website.

Snippets - contributions are welcome. Edited and produced by Dr. B Cole. - drcole@cybersmart.co.za / Fax 011 660 6444 with the help of the Northern Branch Committee.