Articles of the Month 2021
Archive of previous entries
Biopharmaceutical proteins such as antibodies are typically produced in mammalian cells, including the human cell line HEK-293T. The yield of such proteins can be improved by cell line engineering, which aims to balance cell growth, viability and productivity. In June's article of the month, Kronenberg et al. show that a plant regulatory protein known as NtFT4, which controls flowering in response to day length in tobacco, can improve the proliferation of several human cell lines without compromising viability or productivity. The transfection of HEK-293T cells usually reduces the density of viable cells, but the expression of NtFT4 overcomes this hurdle and allows the dense cultivation of transfected cells and thereby increases the yield of a recombinant antibody by more than 30%. This engineering strategy could be combined with other forms of process optimization to boost the yield of recombinant proteins even further.
Article details: Kronenberg J et al. (2021) The tobacco phosphatidylethanolamine-binding protein NtFT4 simultaneously improves vitality, growth and protein yield in human cells. Biotechnol Bioeng (online first, 10/6/2021).
Image shows fluorescence microscopy of HEK-293 cells loaded with the dye Flou-4.
Image credit: Borys Olifirov (CC BY 4.0)
The modification of staple cereals to increase nutrient levels in the seeds is a common approach to develop new varieties that prevent diseases of malnutrition. However, it is often unclear how such interventions affect the metabolism of the vegetative tissues of the same plants, particularly the leaves and roots. In May’s article of the month, Girón-Calva et al. carried out a comprehensive metabolic comparison of normal maize plants and a variety engineered to accumulate carotenoids in the seeds, focusing on the metabolic profiles of the leaves and roots. Not only did they find differences in vegetative metabolism between the two plant lines, but also different responses to high or low levels of nitrogen in the fertilizer. These different vegetative responses arose even before seed development and thus cannot be a direct response to metabolic engineering in the seed, suggesting that the differences are somehow already primed at the embryonic stage. This model of transgenerational metabolic priming could help to predict the outcome of metabolic engineering.
Article details: Girón-Calva PS et al. (2021) Nitrogen inputs influence vegetative metabolism in maize engineered with a seed-specific carotenoid pathway. Plant Cell Rep 40 (5) 899-911.
Image shows a collection of maize cobs.
Image credit: Parmveer Singh (CC BY-SA 3.0).
Apples and pears are consumed all over the world as part of a healthy diet. They provide a rich source of polyphenols, which are complex molecules that demonstrate a range of useful activities in vitro, including antioxidant activity. However, the benefits of dietary polyphenols are difficult to confirm directly because of the varying amounts present in different fruit cultivars as well as differences in absorption and metabolism. In April’s article of the month Commisso et al. investigate the metabolic complexity of six apple and five pear cultivars, and measure their antioxidant capacity in relation to the abundance of different polyphenol compounds. They determined the relationship between metabolic diversity and the genotype of the cultivars and the growing season, and identified cultivars with high levels of polyphenols and low levels of sugars. The metabolic profiling of different fruit cultivars will help consumers to choose fruit products with known health benefits.
Article details: Commisso M et al. (2021) Metabolomic profiling and antioxidant activity of fruits representing diverse apple and pear cultivars. Biology 10 (5) 380.
Image shows a selection of apples and pears.
Image credit: Dimitar Nikolov (CC BY 2.0)
Honeybees are in decline due to a combination of factors including habitat loss, the spread of pathogens and parasites, and the widespread use of pesticides. Honeybees are killed by high doses of pesticides and overwhelming pathogen numbers, but even lower exposure has the potential to induce stress responses that reduce colony fitness. In our article of the month for March, Bartling et al. investigate this phenomenon by testing the effects of a bacterial pathogen and four pesticides on honeybee stress responses and innate immunity when administered at low oral doses. All five stressors affected the mean lifespan of the insects and induced the production of antimicrobial and detoxifying defence factors, but the pesticides triggered a specific effect based on nitric oxide signalling. It may be possible to use these responses as markers to assess the fitness of honeybee colonies.
Article details: Bartling MT et al. (2021) Exposure to low doses of pesticides induces an immune response and the production of nitric oxide in honeybees. Sci Rep 11 (1) 6819.
Image shows the western honeybee Apis mellifera.
Image credit: Reinhard Müller (CC BY-SA 4.0)
High-content screening is a common strategy used to identify new drugs. Large libraries of diverse chemical compounds are tested systematically to determine their effect on a given disease or pathogen, allowing the most promising candidates to be selected for more detailed analysis. The development of drugs for the treatment of COVID-19 can be accelerated by screening compounds that have been tested unsuccessfully against other diseases but may already have passed clinical safety evaluation. In February’s article of the month, Ellinger et al. describe the screening of 5632 compounds (including 3488 previously tested in clinical trials for other diseases) for the ability to inhibit SARS-CoV-2. They identified 258 promising hits that were tested in dose-response trials, ultimately leading to 67 active molecules. This 10-fold reduction in the library size will allow further research to focus on the most promising antiviral molecules.
Article details: Ellinger B et al. (2021) A SARS-CoV-2 cytopathicity dataset generated by high-content screening of a large drug repurposing collection. Sci Data 8 (1) 70.
Image shows the structure of SARS-CoV-2.
Image credit: CDC/Alissa Eckert/Dan Higgins.
Coated films are widely used to protect food, electronic devices and other goods from air and moisture, but the performance of such films is influenced by numerous parameters, including temperature, humidity and exposure to light. In January's article of the month, Kiese et al. determine how temperature influences the transport of water through a plastic film (polyethylene terephthalate) coated with inorganic-organic hybrid polymers and silicon dioxide in different multilayer configurations. They developed equations to predict the behavior of the individual layers and composite films before verifying the predictions experimentally. The temperature dependence of steady-state permeation was found to depend mainly on the silicon dioxide layer, whereas the hybrid polymer layer determined the lag time for vapor transmission. The results can be used to predict the performance of barrier films in different environments, allowing the most appropriate coated films to be selected for a given purpose.
Article details: Kiese S et al. (2021) The influence of temperature on the intrinsic transport properties of water in inorganic and polymeric coatings. Thin Solid Films 717, 138476.