Exploring Nature’s Mysteries! 🌿

In a breathtaking exploration, scientists at the Royal Botanic Gardens, Kew, have identified 74 new plant species and 15 fungi over the past year. These groundbreaking discoveries range from an underground “forest” to spectacular orchids and were found in unlikely places such as the summit of a volcano and clinging to Antarctic rocks.

Nature has once again demonstrated its ability to surprise, with many of these mysterious species urgently requiring protection. Unfortunately, the scientists warn that at least one of these species may have already been lost. Adding to the concern is the revelation that approximately three-quarters of undescribed plants are currently threatened with extinction.

While emphasizing the beauty and wonder of the natural world, the article serves as a stark reminder of the urgent need for biodiversity conservation. The top-10 species newly described to science in 2023 not only showcase the marvels of nature but also sound a warning about the perils of biodiversity loss and climate change.

One of the significant aspects highlighted in the article is the importance of giving a scientific name to these newfound species. According to Dr. Martin Cheek, senior research leader, this is the first step toward implementing protections and exploring potential applications for humanity. Dr. Cheek expresses the sheer sense of wonder that accompanies the discovery of species unknown to the rest of the scientific world and emphasizes its immense significance.

The global discoveries of Kew Gardens for 2023 include three new species of Antarctic fungi, shedding light on the largely unexplored fungal diversity on our planet. The article underscores the potential for discovering new sources of food, medicines, and other active compounds crucial for addressing contemporary challenges.

Among the notable discoveries are an orchid with bright red flowers found on the summit of Mount Nok, an extinct volcano in Indonesia, and an underground palm named Pinanga subterranea discovered on the island of Borneo, Southeast Asia. The article also highlights a peculiar plant, Crepidorhopalon droseroides, from Mozambique, which, though unrelated to other carnivorous plants, uses sticky hairs to attract and potentially digest insects.

Intriguingly, a pair of trees was found living almost entirely underground beneath the Kalahari sands of highland Angola, emphasizing the curious and often overlooked aspects of biodiversity. Another discovery in Madagascar reveals a new orchid, Aeranthes bigibbum, which owes its survival to a unique bird species called the helmet vanga.

Beyond these, the article touches on various other discoveries, including fungi growing on food waste in South Korea, a violet-like flower from Thailand, and an indigo-bearing plant from South Africa.

In closing, the article stresses that on average, scientists name about 2,500 new species of plants and fungi each year, yet it is estimated that as many as 100,000 plants remain formally unidentified. The figure is even higher for fungi, underscoring the vastness of unexplored biodiversity on our planet.

While not conducting this specific research, the Society for Natural and Drug Research (GENAWIF) aligns its mission with understanding and applying the potential of natural substances. As these discoveries shed light on the untapped richness of our natural world, stay tuned for updates from GENAWIF, committed to supporting companies exploring active compounds for medicine and agriculture.

You can read the articel here: https://www.bbc.com/news/science-environment-67930823

Prestigeous award for Genawif collaborator Dr. André Bachmann

Dr. AndrĂ© Bachmann, Professor of Pediatrics at Michigan State University and a collaborator with Genawif, has been honoured with the 2023 NYIPLA “Inventor of the Year Award” for US Patent No. 11,273,137 B2. The New York Property Law Association makes its award annually. The Patent describes the re-purposing of the FDA-approved  drug difluoromethylornithine for the treatment of a rare genetic disorder called Bachmann-Bupp Syndrome. The award is shared by Dr. Bachmann, Dr Bupp and Dr. Rajasekaran and will be presented on 10th May in New York.

https://www.linkedin.com/posts/new-york-intellectual-property-law-association-nyipla-_the-new-york-intellectual-property-law-association-activity-7054521834423115776-SIyA/?utm_source=share&utm_medium=member_ios

Bio4MatPro – Competence Center for Biological Transformation in Materials Science and Production Engineering

Our chairman Dr. Martin Gruhlke gave a presentation on the topic of utilization options of stinging nettle at the conference organized by the Aachen Chamber of Industry and Commerce and the Bio4MatPro project at RWTH Aachen University on February 07, 2023, and participated in the subsequent panel discussion. In addition to the use of stinging nettle fibers as mechanically very stable and high-quality raw materials for the textile industry and the production of bio-based fiber composites, the other very diverse utilization options of the stinging nettle plant such as protein production or vegetable oil production were highlighted.

New research work by GENAWIF members

Selenium is an element very similar to sulfur. The redox activity that makes sulfur so biologically significant is also present in sulfur. Many sulfur compounds, such as those found in onion or cabbage plants, are also extremely antimicrobial. In a cooperative project with Saarland University, Jagiellonian University in Krakow (Poland) and RWTH Aachen University, selenium analogs of so-called thiocyanates, i.e. selenocyanates, were investigated with regard to their antimicrobial potency. The full article, which appeared in the journal Antibiotics, can be found here: https://www.mdpi.com/2079-6382/12/2/290

Allicin from garlic inhibits the essential bacterial enzyme DNA gyrase, a common target for medical antibiotics

For non-experts, we recommend to have a look at our article “Size matters – the importance of DNA packaging and the bacterial DNA Gyrase” first. The article introduces the importance and principles of DNA packaging by comparing the size of Escherichia coli DNA with its actual cell size. Additionally, we demonstrate a simple model of DNA packaging that you can try at home with strings and sticks. Lastly, we explain how the activity of enzymes involved in DNA packaging can be investigated by a technique called DNA gel electrophoresis, a technique used to obtain the results of the study discussed here in the following article.

Summary

The essential bacterial enzyme DNA gyrase is an important target for antibiotics. The enzyme helps to package DNA within the cell, an essential step in DNA- and cell replication. A recent study showed that the natural substance allicin from garlic is a potent DNA gyrase inhibitor, active at a concentration comparable to the antibiotic nalidixic acid. Allicin is a sulfur-containing defence substance synthesized by garlic upon cell damage, and it is responsible for the typical odour of freshly cut or crushed garlic.

Section 1 – Bacterial DNA gyrase is an antibiotic target

Antibiotics are substances that are used in medicine to kill microbes or inhibit their growth. Bacteria have a prokaryotic cell organisation and antibiotic targets can be for example bacterial protein- or DNA synthesis. The specificity of antibiotics is generally high enough so that eukaryotic host cells like human -or animal cells are not-, or only weakly, affected. A little side note here: It should always be kept in mind that the power-plants of our cells (mitochondria) are of bacterial origin and thus can also be sensitive to prokaryotic-targeting antibiotics as well 1,2.

A well-known bacteria-specific antibiotic is penicillin, synthesized by some fungi in the genus Penicillium, and which was described by Alexander Fleming in 1929 3. This antibiotic inhibits cell wall synthesis of many bacteria 4–6. Treatment with antibiotics and the emergence of antibiotic resistance often go hand in hand 7, so that an arsenal of antibiotics with different cellular targets becomes quite handy to combat this phenomenon.

One essential factor for DNA replication in bacteria that is exploited as a target for antibiotic treatment is the enzyme DNA gyrase 8, which belongs to the so-called topoisomerase protein family, that is important for DNA packaging 9.

Section 2 – Allicin from garlic inhibits DNA Gyrase Activity

Nalidixic acid (Figure 1), which is a purely chemically synthesized antibiotic, was the first antibiotic of the so-called quinolone class that turned out to be an effective inhibitor of DNA gyrase activity 10.

Chemical structure of nalidixic acid and allicin
Figure 1: Chemical structure of nalidixic acid and allicin. While nalidixic acid is made solely via chemical synthesis, allicin is a natural antibiotic compound of garlic (Allium sativum), which is also responsible for the typical garlic odour. Pure Allicin can also be chemically synthesized.

In 2020, a study by Jana Foerster (neé Reiter) and colleagues was published about the gyrase inhibitory mode of action of allicin 11, a natural sulfur compound from garlic (Figure 1). Allicin is a strong volatile antibiotic released from garlic cells after cellular damage and is the reason for the typical odour of freshly crushed garlic. Compared to other antibiotics with very specific targets, allicin attacks multiple targets in the cell at once because of its reactivity with available thiol groups in cysteines which are essential for the structure and activity of many enzymes 12,13.

When allicin reacts with a thiol group, this group becomes chemically oxidized and a so-called allyl group is added to it (Figure 2). This allyl-group addition also increases the mass of the proteins, and this mass difference was used by Foerster et al. to investigate which proteins became thioallylated after allicin treatment in Pseudomonas bacteria 11.

Allicin reacts with thiol groups in biomolecules
Figure 2: Allicin reacts with thiol groups in biomolecules. In this example, allicin reacts with accessible thiol groups (-SH) on the surface of proteins. One molecule of allicin is able to thioallylate two thiol groups, either on the same – or on two different biomolecules. The molecular mass of the protein increases by the addition of the allyl-group (red). This mass increase can be detected by mass-spectroscopy analysis to identify the specific proteins as well as the proportion that becomes oxidized after allicin treatment.

Foerster (neé Reiter) et al. were looking for potential resistance mechanisms against allicin by investigating the differences between thioallylated proteins in an allicin-resistant bacterium that was isolated from garlic, called Pseudomonas fluorescens Allicin Resistant-1 (PfAR-1), compared to its close, but allicin-sensitive, relative P. fluorescens Pf0-1 11. The working hypothesis was that proteins that were less thioallylated by allicin in PfAR-1 might be a resistance factor for bacterial survival during allicin stress.

By using a differential isotopic labelling method (OxICAT) pioneered by Professor Lars Leichert and colleagues 14, the thioallylated proteins, as well as the degree of allylation in the population of specific protein could be characterized in PfAR-1 and Pf0‑1 after allicin treatment. In this first part of Foerster (neé Reiter) et al.´s work, one candidate turned out to be the DNA gyrase protein subunit A (GyrA) because of a very significant difference observed between Pf0-1 and PfAR-1. In Pf0-1, the amount of oxidized GyrA proteins increased from 6.3 % to 56.1 %, while the amount of oxidized GyrA proteins in PfAR-1 only increased from 6.5 % to 10.8 %. The conclusion of these data was that up to 49.8 % of all GyrA protein molecules in Pf0‑1 became thioallylated, while only 4.3 % of all GyrA protein in PfAR‑1 became thioallylated 11.

Since the allylation of GyrA in Pf0-1 does not allow the conclusion that the DNA gyrase enzyme would also be inhibited by that modification, enzymatic assays were performed to address this question (Figure 3).

Nalidixic acid as well as allicin from garlic inhibit DNA gyrase activity
Figure 3: Nalidixic acid as well as allicin from garlic inhibit DNA gyrase activity. This is a graphic summary of some of the results from Foerster (née Reiter) et al. from 2020 11. Plasmid DNA can be easily obtained from an E. coli liquid culture in high amounts. (1.) The plasmid DNA (here: from pUC19 plasmid) is in its natural supercoiled state. (2.) The isolated plasmid can be converted to fully relaxed plasmid DNA via DNA topoisomerase I. (3.) DNA gyrase converts the relaxed DNA back to its supercoiled state. (4.) Since relaxed and supercoiled DNA can be distinguished by their rates of movement on an agarose gel, DNA gyrase inhibitors can be investigated by pre-treating DNA gyrase prior its use. Boiling DNA gyrase serves as positive control for inactivated DNA gyrase activity. As it can be seen, nalidixic or allicin inhibit DNA gyrase activity in a concentration dependent manner.

The assay was based on the different mobilities between relaxed and supercoiled DNA on electrophoresis in an agarose gel in a certain time. As the pUC19 plasmid DNA would be converted to supercoiled pUC19 by DNA gyrase, the more compact supercoiled DNA would move faster through an agarose gel compared to the relaxed pUC19 DNA. With boiled DNA gyrase compared to untreated DNA gyrase, the assay worked as expected, so that the effect of nalidixic acid and allicin pre-treatment of DNA gyrase could be investigated, showing that both substances are potent inhibitors of the enzyme in a concentration-dependent manner (Figure 3) 11.

Interestingly, both the DNA gyrase from Pf0-1 and PfAR-1 were inhibited by allicin in vitro to the same degree. The difference seen in thioallylation in vivo after allicin treatment reflected the ability of resistant PfAR-1 cells to protect their proteins against thioallylation compared to the sensitive Pf0-1 cells 15. The ability of allicin to inhibit DNA gyrase is an important observation and helps to explain allicin’s antibacterial activity 11.

However, at present, without more research and testing, allicin cannot be used as a substitute for other antibiotics and it should not be used for self-treatment, which can be very harmful.

Jan Borlinghaus, 13.10.2022

References

  1. Gray, M. W.; Burger, G.; Lang, B. F. Mitochondrial Evolution. Science 1999, 283 (5407), 1476–1481. https://doi.org/10.1126/science.283.5407.1476.
  2. Singh, R.; Sripada, L.; Singh, R. Side Effects of Antibiotics during Bacterial Infection: Mitochondria, the Main Target in Host Cell. Mitochondrion 2014, 16, 50–54. https://doi.org/10.1016/j.mito.2013.10.005.
  3. Fleming, A. On the Antibacterial Action of Cultures of a Penicillium, with Special Reference to Their Use in the Isolation of B. Influenzæ. British journal of experimental pathology 1929, 10 (3), 226–236.
  4. Tipper, D. J.; Strominger, J. L. Mechanism of Action of Penicillins: A Proposal Based on Their Structural Similarity to Acyl-D-Alanyl-D-Alanine. Proceedings of the National Academy of Sciences 1965, 54 (4), 1133–1141. https://doi.org/10.1073/pnas.54.4.1133.
  5. Cho, H.; Uehara, T.; Bernhardt, T. G. Beta-Lactam Antibiotics Induce a Lethal Malfunctioning of the Bacterial Cell Wall Synthesis Machinery. Cell 2014, 159 (6), 1300–1311. https://doi.org/10.1016/j.cell.2014.11.017.
  6. Park, J. T.; Strominger, J. L. Mode of Action of Penicillin. Science 1957, 125 (3238), 99–101. https://doi.org/10.1126/science.125.3238.99.
  7. MacLean, R. C.; San Millan, A. The Evolution of Antibiotic Resistance. Science 2019, 365 (6458), 1082. https://doi.org/10.1126/science.aax3879.
  8. Collin, F.; Karkare, S.; Maxwell, A. Exploiting Bacterial DNA Gyrase as a Drug Target: Current State and Perspectives. Applied Microbiology and Biotechnology 2011, 92 (3), 479–497. https://doi.org/10.1007/s00253-011-3557-z.
  9. Champoux, J. J. DNA TOPOISOMERASES: Structure, Function, and Mechanism. Annu. Rev. Biochem. 2001, 0 (errata). https://doi.org/10.1146/annurev.bi.70.010101.200002.
  10. Lesher, G. Y.; Froelich, E. J.; Gruett, M. D.; Bailey, J. H.; Brundage, R. P. 1,8-NAPHTHYRIDINE DERIVATIVES. A NEW CLASS OF CHEMOTHERAPEUTIC AGENTS. J Med Pharm Chem 1962, 91, 1063–1065. https://doi.org/10.1021/jm01240a021.
  11. Reiter, J.; HĂĽbbers, A. M.; Albrecht, F.; Leichert, L. I. O.; Slusarenko, A. J. Allicin, a Natural Antimicrobial Defence Substance from Garlic, Inhibits DNA Gyrase Activity in Bacteria. International Journal of Medical Microbiology 2020, 310 (1), 151359. https://doi.org/10.1016/j.ijmm.2019.151359.
  12. Borlinghaus, J.; Albrecht, F.; Gruhlke, M. C. H.; Nwachukwu, I. D.; Slusarenko, A. J. Allicin: Chemistry and Biological Properties. Molecules 2014, 19 (8), 12591–12618. https://doi.org/10.3390/molecules190812591.
  13. Borlinghaus, J.; Foerster (née Reiter), J.; Kappler, U.; Antelmann, H.; Noll, U.; Gruhlke, M. C. H.; Slusarenko, A. J. Allicin, the Odor of Freshly Crushed Garlic: A Review of Recent Progress in Understanding Allicin’s Effects on Cells. Molecules 2021, 26 (6). https://doi.org/10.3390/molecules26061505.
  14. Leichert, L. I.; Gehrke, F.; Gudiseva, H. V.; Blackwell, T.; Ilbert, M.; Walker, A. K.; Strahler, J. R.; Andrews, P. C.; Jakob, U. Quantifying Changes in the Thiol Redox Proteome upon Oxidative Stress in Vivo. Proc Natl Acad Sci USA 2008, 105 (24), 8197. https://doi.org/10.1073/pnas.0707723105.
  15. Borlinghaus, J.; Bolger, A.; Schier, C.; Vogel, A.; Usadel, B.; Gruhlke, M. C.; Slusarenko, A. J. Genetic and Molecular Characterization of Multicomponent Resistance of Pseudomonas against Allicin. Life Sci. Alliance 2020, 3 (5), e202000670. https://doi.org/10.26508/lsa.202000670.

International Conference of our German Society for Plant Sciences

At this year’s botanical meeting, hosted by the German Botanical Society (www.deutsche-botanische-gesellschaft.de) at the University of Bonn, our chairman Dr. Martin Gruhlke gave a lecture on “Thioallylation as the basis for the physiological effect of allicin in garlic” and was session chair in the session “Plants and Human Health” together with Prof. Stanislav Kopriva. Besides many fascinating presentations, there was a lot of interesting exchange in the field of plant sciences, which are a central element for GENAWIF.

Size matters – the importance of DNA packaging

Summary

The following article introduces the importance of DNA size management due to limited cellular space, as it is demonstrated with the DNA and cell size of the Escherichia coli bacterium. The very principles of DNA packaging are discussed using a simple sticks-and-strings model that you can try at home. Since DNA packaging is a much more sophisticated process with various structural proteins and enzymes involved, the bacterial enzymes DNA gyrase and DNA topoisomerase I are introduced as well as an easy and well-established assay to monitor their DNA modifying activity. The assay can be used to screen for new DNA gyrase inhibitors, an important target of medical antibiotics.

Section 1 – DNA is used to store high amounts of biological information

All the information about the cellular structure of an organism, its proteins needed for biochemical reactions, and genetic circuits to adapt to changing environmental conditions are stored physically on DNA molecules. Simply spoken, every biological detail of an organism is encoded in its DNA, which is quite much of information. Thus, as we will see, the absolute size of DNA exceeds the actual cell size, which is why the DNA has to be packaged and condensed to fit in its host cell.

Section 2 – The DNA structure and terms that are used to refer to DNA length

Firstly, we need to explain the units and terms that are used to express the length or size of DNA molecules. DNA molecules are made up of two strands wound around each other to make the familiar double helix one sees in illustrations (Figure 1). One strand is made up of a chain of bases joined along a sugar-phosphate backbone, and each base in a strand pairs with a base in the opposite strand giving a unit called a base pair (bp)in the DNA double helix 1. Thus, the length of a DNA molecule can be expressed as a number of base pairs (bp).

A simplified scheme showing the structure of DNA
Figure 1: A simplified scheme showing the structure of DNA. DNA helices consists of two single molecular strands that are attached to each other via base paring with hydrogen bonds, represented here by vertical lines between the bases adenine (A) and thymine (T) and cytosine (C) und guanine (G). The bases are covalently bound to a sugar-phosphate backbone, and their serial sequence represents genetic information which can be read and interpreted by cells. Due to the arrangements and the connection of the different DNA components to each other, the natural conformation of DNA is helical.

DNA molecules are classified depending on their size, structure and function. For example, chromosomes are the largest DNA molecules in a cell with all the genes that are necessary for fundamental cellular function. In higher organisms the chromosomal DNA is the sum of several different chromosomes. In contrast, the DNA in bacteria that makes up the bacterial chromosome is, in most cases, a single long DNA molecule joined together at the ends to make a circle 2.

Section 3 – Escherichia coli´s DNA- and cell size

The chromosome of Escherichia coli K12, a common laboratory bacterial strain, has a size of 4.6 mega bp which is 4.6 million bp of DNA 3.Knowing that each base pair is approximately 0.34 nm long 4, the physical length of the “DNA string” of the E. coli genome can be calculated to have a length of 0.34 nm x 4,600,000 bp = 1,564,000 nm, which is a DNA molecule about 1.5 mm long, a dimension visible to the human eye (Figure 2). If a 1.5 mm string is used to form a perfect circle which would be a closer fit to the real DNA structure of the E. coli chromosome, the diameter of this circle can be calculated to approximately 0.5 mm, a size also still visible by the naked eye. 

length of the Escherichia coli genome
Figure 2: The length of the Escherichia coli genome compared to its actual size within the bacterial cell. The DNA is composed of a string of covalently bound nucleotides. Each nucleotide has one of four different bases, which form hydrogen bonds with corresponding complementary bases of another string, resulting in two parallel strings of DNA. Given the length of 0.34 nm between base pairs (bp), the E. coli genome with a size of 4.6 million base pairs is 1,564,000 nm long, which equals 1,564 µm or 1.5 mm. Based on this length, the diameter of a perfect circular molecule which would be closer to the real structure of the E. coli genome can be calculated to 0.5 mm (500 µm). Thus, the chromosomal DNA of E. coli is still more than 100 to 200 times bigger than its actual cell size.

Since E. coli cells are so small that we cannot see them with the naked eye, 0.002-0.004 mm long and 0.001 mm in diameter 5–7, it is clear that the chromosomal DNA has to be packed into a smaller form, which scientists call the nucleoid 8 (Figure 2).

Section 4 – A simplified model of DNA packaging

When being packaged, the DNA double strand crosses over itself several times forming super coils, which is the form of condensed or packed DNA within the cell. In this condensed form, the DNA can be stored very compactly, like folding a 2-meter-long ruler to fit in your pocket.

A simple model that can be reproduced at home with two strings and two sticks can nicely demonstrate the principles of DNA packaging (Figure 3). The two strings represent two parallel DNA single strands. If each end of this double strand is tied to a stick forming two parallel strands, and if you turn one stick around while holding the other in position, and fold the DNA to bring the sticks closer together, the DNA becomes twisted. As both sticks to come closer upon repeated folding, the DNA curls up and forms coils which reduces the tension overall in the molecule.

A simple model of DNA packaging
Figure 3: A simple model of DNA packaging to fit the long DNA molecule neatly into a small space. The linear DNA consists of two strands of DNA strings, connected by the hydrogen bonds between complementary DNA bases (vertical lines between the horizontal strings). If both ends of the linear DNA string are tied to fixed ends, and one end is twisted, the DNA becomes twisted as well. Twisted DNA is neatly folded, and sticking to this model, a tension is built up between both ends which is released by allowing both ends to come closer to each other, while the DNA relaxes by forming coiled structures.

As with everything in Biology, the packaging (condensation) and un-packaging (de-condensation) of DNA is quite complicated and involves several enzymes and structural proteins that modify and stabilize the shape of the DNA. Enzymes that actively participate in DNA condensation and de-condensation belong to the so-called topoisomerase protein family (nicely reviewed for example by Champoux 9).

DNA packaging is not a once in a lifetime event, because each time a gene is transcribed or the DNA is replicated, the DNA must be locally or totally de-condensed, respectively. In principle, one can compare DNA with a book in which a specific page is opened (de-condensed) for copying (transcribing) a certain passage of genetic information. The page is then turned over, closing (condensing) the passage, and the transcript of this passage is then used to perform an assignment in the cell. DNA condensation and de-condensation are, thus, essential for cellular function and cell replication, and impairing enzymes responsible for this process is generally lethal, which is why bacteria-specific topoisomerases like DNA gyrase are valuable targets for antibiotic treatment 10.

Section 5 – Visualizing the activity of DNA packaging enzymes via simple agarose gel electrophoresis

Using DNA gyrase and topoisomerase I, enzymatically assisted packaging and un-packaging of DNA can nowadays be simply demonstrated in the laboratory. But first of all, what does these enzymes do? In a nutshell, DNA gyrase actively increases the number of twists, and the higher the number of twists, the more looped and compact the DNA gets. In more detail, DNA gyrase grasps two strands. Then, one strand is cut and the other strand is pulled through the generated opening, followed by rejoining of the cut strand by DNA gyrase 10. On the other hand, DNA topoisomerase I actively relaxes the supercoiled DNA by cutting and re-joining the strands after allowing unwinding to occur 9 (Figure 4).

Now that we know our enzymes, we need to think about the DNA sample that can be used to be enzymatically modified and investigated. So far, we discussed the size and packaging of DNA using genomic DNA as an example. However, for experimental purposes, Plasmid DNA is a better choice. Plasmids are circular but smaller, autonomously replicating DNA molecules that co-exist with the chromosomal DNA in the bacterial cell, often in high copy number. Since small plasmid DNA is much easier to isolate and to handle than chromosomal DNA, plasmid DNA is a good experimental material to use to investigate DNA Gyrase and Topoisomerase I activity (Figure 4).

A method to investigate DNA topoisomerase activity
Figure 4: A method to investigate DNA topoisomerase activity. Circular relaxed plasmid DNA can be converted to supercoiled DNA via DNA gyrase, and supercoiled DNA can be converted back to relaxed plasmid DNA by DNA topoisomerase I. The action of both enzymes can be monitored if the DNA is analysed after enzymatic treatment. Although the relaxed- and supercoiled DNA still have the same absolute size, the supercoiled DNA is much more compact and can run through the meshwork of an agarose gel faster within a certain time than the less compact relaxed DNA on the same gel.

Lastly, we need to analyse the structural changes made by the enzymes to our DNA substrate. DNA conformation analysis is quite simple using an agarose gel, which is a polymer building a meshwork serving as a molecular sieve with a pore size depending on the agarose concentration used. The denser this meshwork is the more time is needed for DNA molecules to squeeze through when pulled along by an electrical current (electrophoresis).

The gel is put in a chamber with conducting buffer, the DNA samples are then loaded in pockets within the gel, and by applying an electrical field via two electrodes in the chamber, dissolved substances with an electrical charge wander through the gel towards the oppositely charged electrode. With the negatively charged cathode at the top, the negatively charged DNA molecules are pulled through the agarose gel towards the positively charged anode at the bottom. The more compact the DNA molecules are, the faster they can move through the agarose gel meshwork. Thus, packaged DNA with less steric hindrance would run further through the gel compared to un-packed DNA of the same number of bp within a certain time.

This kind of assay can easily be used to screen for additional DNA gyrase inhibitors that could be new antibiotic candidates. Although already having antibiotics at hand that inhibit DNA gyrase activity, antibiotic usage is often accompanied by antibiotic resistance development 11. Thus, it is always reasonable to look for alternative antibiotics.

For example, in another study, the herein explained gel electrophoresis assay was used to monitor DNA gyrase activity after treatment with allicin from garlic 12. We also summarized this study in another article on our website, entitled “Allicin from garlic inhibits the essential bacterial enzyme DNA gyrase, a common target for medical antibiotics”, which would be the perfect follow-up for you to read!

Jan Borlinghaus, 13.09.2022

References

  1. Alberts, B.; Johnson, A.; Lewi, J.; Raff, M.; Roberts, K.; Walter, P. The Structure and Function of DNA. In Molecular Biology of the Cell.; Garland Science: New York, 2022.
  2. diCenzo, G. C.; Finan, T. M. The Divided Bacterial Genome: Structure, Function, and Evolution. Microbiology and Molecular Biology Reviews 2017, 81 (3), e00019-17. https://doi.org/10.1128/MMBR.00019-17.
  3. Blattner, F. R.; Plunkett, G.; Bloch, C. A.; Perna, N. T.; Burland, V.; Riley, M.; Collado-Vides, J.; Glasner, J. D.; Rode, C. K.; Mayhew, G. F.; Gregor, J.; Davis, N. W.; Kirkpatrick, H. A.; Goeden, M. A.; Rose, D. J.; Mau, B.; Shao, Y. The Complete Genome Sequence of Escherichia Coli K-12. Science 1997, 277 (5331), 1453. https://doi.org/10.1126/science.277.5331.1453.
  4. Langridge, R.; Wilson, H. R.; Hooper, C. W.; Wilkins, M. H. F.; Hamilton, L. D. The Molecular Configuration of Deoxyribonucleic Acid: I. X-Ray Diffraction Study of a Crystalline Form of the Lithium Salt. Journal of Molecular Biology 1960, 2 (1), 19-IN11. https://doi.org/10.1016/S0022-2836(60)80004-6.
  5. Volkmer, B.; Heinemann, M. Condition-Dependent Cell Volume and Concentration of Escherichia Coli to Facilitate Data Conversion for Systems Biology Modeling. PLoS One 2011, 6 (7), e23126–e23126. https://doi.org/10.1371/journal.pone.0023126.
  6. Reshes, G.; Vanounou, S.; Fishov, I.; Feingold, M. Timing the Start of Division in E. Coli: A Single-Cell Study. Phys Biol 2008, 5 (4), 046001. https://doi.org/10.1088/1478-3975/5/4/046001.
  7. Pierucci, O. Dimensions of Escherichia Coli at Various Growth Rates: Model for Envelope Growth. J Bacteriol 1978, 135 (2), 559–574. https://doi.org/10.1128/jb.135.2.559-574.1978.
  8. Verma, S. C.; Qian, Z.; Adhya, S. L. Architecture of the Escherichia Coli Nucleoid. PLOS Genetics 2019, 15 (12), e1008456. https://doi.org/10.1371/journal.pgen.1008456.
  9. Champoux, J. J. DNA TOPOISOMERASES: Structure, Function, and Mechanism. Annu. Rev. Biochem. 2001, 0 (errata). https://doi.org/10.1146/annurev.bi.70.010101.200002.
  10. Collin, F.; Karkare, S.; Maxwell, A. Exploiting Bacterial DNA Gyrase as a Drug Target: Current State and Perspectives. Applied Microbiology and Biotechnology 2011, 92 (3), 479–497. https://doi.org/10.1007/s00253-011-3557-z.
  11. MacLean, R. C.; San Millan, A. The Evolution of Antibiotic Resistance. Science 2019, 365 (6458), 1082. https://doi.org/10.1126/science.aax3879.
  12. Reiter, J.; HĂĽbbers, A. M.; Albrecht, F.; Leichert, L. I. O.; Slusarenko, A. J. Allicin, a Natural Antimicrobial Defence Substance from Garlic, Inhibits DNA Gyrase Activity in Bacteria. International Journal of Medical Microbiology 2020, 310 (1), 151359. https://doi.org/10.1016/j.ijmm.2019.151359.

Powerful new analytical technique makes the smell of garlic and other plants visible.

When you investigate something, your method can distort your results. This is a problem in lots of research and a case in point is trying to analyse the molecules that make up the smell of garlic. Many analytical methods actually alter the molecules being investigated, for example if they are degraded by heat. For example, gas chromatography is unsuitable because of the high temperatures routinely employed. This is especially true for the heat-sensitive, reactive, volatile organic sulfur compounds from alliums, like garlic, ramsons and onion, and so it is difficult to be sure what you find is a true picture of what you are looking for.

On-line gas analysis in real time, using a particularly gentle, low temperature ionisation of molecules in the air, followed by high-resolution mass-spectrometry (SESI-Orbitrap MS), has been applied to crushed garlic, onions, ramsons and even human “garlic breath” for the first time at the RWTH Aachen University. As the molecules diffuse into the gas phase from the source, they are “breathed” into the analytical apparatus and analysed within seconds under very gentle conditions, avoiding extremes of temperature. This has revealed some very interesting food chemistry and you can read about it in the following publication in Food Chemistry (https://doi.org/10.1016/j.foodchem.2022.133804) 1.

Alan Slusarenko, 22.08.2022

(1)          Mengers, H. G.; Schier, C.; Zimmermann, M.; C. H. Gruhlke, M.; Block, E.; Blank, L. M.; Slusarenko, A. J. Seeing the Smell of Garlic: Detection of Gas Phase Volatiles from Crushed Garlic (Allium Sativum), Onion (Allium Cepa), Ramsons (Allium Ursinum) and Human Garlic Breath Using SESI-Orbitrap MS. Food Chemistry 2022, 397, 133804. https://doi.org/10.1016/j.foodchem.2022.133804.

The uncertain future for many Scientists and the non-profit organization as a link between public and private sector research

To spread the idea of GENAWIF and for letting our network grow, it is important to get in touch with all interested groups that we can work with, which are scientists, the private sector economy, the general public, and especially Politicians, since they offer the framework for all of us. Thus, to get to know each other, exchange ideas and reflect about GENAWIF, we invited Ulla Thönnissen, member of the parliament of the state of North Rhine Westphalia (NRW). Mrs. Thönnissen is not only a member of the Science Committee of NRW, but also of several non-profit associations, thus having experience in a lot of topics that are in common with GENAWIF’s aims (https://www.ulla-thoennissen.de/).

After we gave a very short presentation about GENAWIF, Mrs. Thönnissen was very interested in why we chose a non-profit organization as a framework for our activities instead of a Start-Up. That was our motivation to address this topic in this article because we wanted to share the key essence of that lively and interactive discussion.

When we had to decide about the legal form of GENAWIF as a framework for our activities, we had the choice between a non-profit organization and a small company as a classical Start-Up. The foundation of a small company would have led to a so called “kleines mittelständisches Unternehmen“ (KMU) which stands for “small medium sized company“. These details are important because formal regulations differ depending on the size of your company and on the annual turnover, and a KMU would be the smallest option, often with the advantage of less self-investment for grant applications.

However, money was not the only consideration. It might sound a little bit odd, but as a company, you are forced to choose your research according to immediate profitability so that your company is sustainable and grows. But allicin is yet not ready for application and still needs more research for that purpose. On the other hand, we had already seen a huge potential regarding the health- and agricultural sector, and we did not want to give up on that.

Additionally, the most efficient work is done for something you are passionate about, and in most cases not just for money. As a non-profit organization, we are able to apply for grants to support fundamental research with much less financial self-investment, but we often depend on other companies as a cooperation partner for grant applications. In the end, that is a big opportunity to get in touch with other people, and new ideas. In addition, the workload is shared and each partner can concentrate on their key abilities and expertise.

Regarding our background coming from a public university, one could say that we could have stayed with the University, and that a Start-Up might have been better because of the huge support Start-Ups often receive from universities. However, without a patent application at that time, chances for successful funding grants for Start-Up development were not really an option, and due to the “Wissenschaftszeitgesetz”, we would not have had enough time left without grant money to reach this requirement in time.

The “Wissenschaftszeitgesetz” is a German law regulating the time a scientist can be employed at the University, which is six years before and then six years after completing the PhD. You can circumvent this rule if you are successful in grant applications to pay your own salary, because employment via grant money does not count regarding the time limit given by the “Wissenschaftszeitgesetz“. Another possibility would be to get a permanent job at the university.

However, permanent employment at the University is quite rare, not only from our personal impressions but also according to statistics. Up to 98% of researchers in the public domain are temporarily employed, and that did not change from 2015 (https://de.statista.com/infografik/25278/wissenschaftlicher-nachwuchs-an-hochschulen-mit-befristeten-vertraegen/ up to 2022 (Bundesbericht Wissenschaftlicher Nachwuchs 2021, https://www.buwin.de/). Some years ago, the hashtag #ichbinhanna which translates to “I am hanna“ addressed this issue and brought it into the public awareness, exemplifying the situation of an imaginary scientist called Hanna. That initiative started an enormous wave of feedback by scientists who identified themselves with her plight (https://ichbinhanna.wordpress.com/).

These circumstances can be quite stressful for young scientists and do not offer an attractive perspective to settle down and start a family, for example. Highly qualified scientists therefore most often go in the private sector or move to another country. Additionally, scientists often end up in careers that have nothing to do with research anymore. However, to be fair, it must be stated that not all scientists can remain at the university because the system would overgrow and crash without new financial concepts.

To sum up, we could not have stayed at the University for much longer, and going into industry would have meant abandoning years of research started at the university, because there was no way to continue seriously with our ideas just with spare time after regular work without the required facilities.  Additionally, if we were to work with companies in our role as employees of the University, a significant proportion of money for contract research would go into overhead costs. On the one hand that is justified, because laboratory and administrative infrastructure support of universities needs to be paid for, but the project costs would be much less for a smaller association with a smaller infrastructure, resulting in more money for research instead for maintenance costs.

With all this in mind, our vision with GENAWIF is not just self-sustainment. We want to be pioneers and an example to establish a third alternative for scientists besides public research and private economy. GENAWIF is a hybrid with advantages from both aspects, but of course also less options on its own without collaborations and support.

Besides talking about our daily work routine like networking and getting involved in public relations, we also talked with Mrs. Thönnissen in detail about our scientific background and the research from our time at the University that we want to continue (which is addressed in this article). We were glad to talk about new projects, like recycling opportunities for biological waste from agriculture, the development of new fertilizers or the protection of plants from pathogens with new protection strategies using natural products.

Due to their bio-economical potential, Mrs. Thönnissen mentioned that our projects and application-oriented research might fit with the aims of the Wirtschaftsstrukturprogramm (WSP) of the “Rheinisches Revier“ initiative (www.rheinisches-revier.de). This initiative addresses the structural change that has to follow due to the decision to quit brown coal (lignite) mining (German “Kohleausstiegsgesetz from August 2020) by funding innovations and ideas to create a climate-friendly regional economy (German “Strukturstärkungsgesetz Kohleregion“, also from August 2020). We want to thank Mrs. Thönnissen for her time and her input for how our young association could improve and grow!

Just a few days after the meeting with Mrs. Thönnissen, we had the opportunity to take part in the kick-off event from ZukunftBio.NRW (https://www.zukunftbio.nrw/) which took place in Düsseldorf NRW. During this event, we learned a lot about the legal framework and regulations regarding the WSP of the “Rheinisches Revier“ initiative.

Jan Borlinghaus, 13.07.2022

Participation in the Food Bioactives and Health Congress in Parma, Italy

Dr. Martin Gruhlke, Chairman of GENAWIF e.V., participated in the 3rd Food Bioactives and Health Congress in Parma, Italy. There he presented work on thioallylation of proteins by allicin from garlic. Thioallylation is an alteration of certain amino acid residues in proteins that affects protein function. Bioactive compounds in food are an exciting topic that offers many starting points for GENAWIF e.V. to better understand the mode of action of natural and active compounds and to evaluate new application options.