UPWr scientists with Opus 16 grants

1,302,000 PLN in the Opus 16 competition of the National Science Centre went to professor Aleksandra Mirończuk from the Department of Biotechnology and Food Microbiology. She will study the metabolic pathways of the Yarrowia lipolytica yeast. The consortium led by the UPWr Institute of Soil Science and Environmental Protection, with prof. Jerzy Weber as its project manager will examine spectroscopic and chemical properties of soil humin fractions with reference to their interaction with pesticides. The partners in this grant are the Institute of Cultivation, Fertilization and Soil Science NRI in Puławy, Department of Physics and Agrophysics of the West Pomeranian University of Technology in Szczecin and the Faculty of Chemistry of the University of Wrocław. The total value of the grant is 1,263,000 PLN, 577,300 of which will go to our University. Another consortium (the leader of which is the Poznań University of Life Sciences and Prof. Magdalena Rudzińska) will examine the physicochemical and biological properties of sterol glycerides and their products formed during thermal oxidation. On the part of UPWr the following scientists will participate: dr inż. Aleksandra Grudniewska, dr hab. Anna Chojnacka and prof. Witold Gładkowski from the Department of Chemistry, and prof. Hanna Pruchnik and Aleksandra Włoch PhD from the Department of Physics and Biophysics. UPWr will receive a PLN 488,600 share in the grant. Tomasz Piasecki PhD, who received 210,000 PLN, will look for answers to the question why birds are resistant to Shiga toxins produced by the virulent strains of Escherichia coli.

Yeast under observation

The project carried out by Prof. Aleksandra Mirończuk aims at identifying the enzymes responsible for processing erythritol in Yarrowia lipolytica cells.

Erythritol produced by microorganisms subjected to high osmotic pressure (the pressure dangerous to them because it causes water to "escape" from cells) has sweet taste and occurs naturally in food. It is also a revelation of recent years – its low calorie content meant that it was considered a great sweetener to replace sugar, which is, in addition, removed from the body together with urine in an unchanged form and in almost 100 percent. Recent studies, however, show that we do not know everything about erythritol. First of all, this compound may be subject to metabolic changes taking place in the human body. Secondly – it has been identified as a biomarker. Human cells begin to produce it many years before the onset of obesity and associated diseases. It is not yet known how these processes take place. Since studying their enzymatic pathways in complex animal organisms is difficult, the choice fell on yeast – many of their metabolic transformations are similar to those in complex systems and, in addition, they produce erythritol on an industrial scale.

- The erythritol synthesis pathway is well described, but it has been observed that Yarrowia lipolytica, which is used to produce this compound, after the depletion of the substrate, begins to utilize what it produced earlier. Stopping this process allows us to improve the parameters of industrial production, which we already know from the preliminary research, during which the protein responsible for activating the erythritol assimilation process was identified. As you can see, we still have a lot to discover here and the project for which we have received funding is supposed to help us discover new metabolic pathways in Yarrowia lipolytica yeast - explains prof. Mirończuk.

Caring about soil

The consortium led by the Wrocław University of Environmental and Life Sciences, under a grant whose total cost was estimated at PLN 1,263,000, will examine the processes of interaction between humins and the active substances of pesticides used in agriculture.

Chemical plant protection products have been successfully used for many years to prevent crop reduction, despite their negative impact on the environment. The organic matter of the soil, especially humic substances, is a natural filter that captures all kinds of pollution in ecosystems, including pesticides. Humics are created as a result of biochemical transformations of organic remains getting into the soil, and their presence determines the quality of the soil, although their content is very small. In the topsoil of chernozems and phaeozems it reaches 4-5%, and in other soils it is usually lower than 2%. Their presence affects many soil properties, including its permeability and water storage capacity, but also the storage of nutrients which are necessary for plant existence. It is known that they play an important role in the accumulation and movement of pesticides in the environment. Humins are the least recognized fraction of soil humus substances due to their complicated isolation from soil material and difficulties in testing their properties. For this reason, it was necessary to establish a consortium with appropriate equipment facilities.

- Four leading laboratories in the country specializing in spectroscopic examination of soil will check how humins react with selected active substances of pesticides and their commercial preparations - explains prof. Jerzy Weber, the project manager and adds that scientists participating in the implementation of this grant will also carry out research on the impact of these processes on the properties of the humin fractions. The tested humic substances will be isolated from the topsoil levels of chernozems and phaeozems that occur in various regions of Poland.

Sterols for health

Aleksandra Grudniewska PhD from the Department of Chemistry will participate in the implementation of the project whose leader is the University of Life Sciences in Poznan. Our university will receive PLN 488,600 to study the physicochemical and biological properties of sterol glycerides and their products formed during thermal oxidation.

Sterols are an important component of fats and they perform important metabolic functions. They are a source of hormones, a precursor of vitamin D, but also a component of cell membranes. We know animal sterols, whose main representative is cholesterol, but also plant sterols or those produced by microorganisms, e.g. mould fungi.

- Plant sterols reduce cholesterol in the human body. They are found in vegetable oils, vegetables, fruit stones and they are also added to food products as functional ingredients. But although they have very important, positive effects, phytosterols applied in high doses reduce vitamin E and carotenoids. Their oxidative stability is important – oxidized derivatives have an adverse effect, exhibit cytotoxic properties, contribute to the formation of oxidative stress. Elevated levels of oxyphytosterols, i.e. oxidized derivatives, are observed in diabetics, but we still know too little about their effects on a sick body – explains Aleksandra Grudniewska.

Two Poznań universities: the University of Life Sciences and the University of Medical Sciences conduct research on the impact of phytosterol degradation products on normal cells of the digestive system. It has been discovered that compounds formed during the thermal processing of stigmasterol, naturally occurring in soybeans (which is used in the pharmaceutical industry and in the synthesis of hormones), have a negative effect on cells.

- The food available on the market is widely enriched with plant sterols due to their anti-cholesterol effect. It is important, however, that these phytosterols are safe for humans. And our task is to create a completely safe form of stigmasterol - says Aleksandra Grudniewska.

Checking bird resistance

Using his grant, Tomasz Piasecki PhD will try to answer the question why birds are resistant to Shiga toxin produced by enterohaemorrhagic Escherichia coli strains. E. coli live in human intestines, but in this large family of microbes there are also strains dangerous to humans. One of them is enterohaemorrhagic E. coli, which cause haemorrhagic colitis leading to life-threatening hemolytic-uremic syndrome.

- Children between 6 months and 4 years of age are particularly vulnerable to this complication leading to acute renal failure, but it can also occur in older people. For both these groups it may be fatal. In Germany in 2011 there was an epidemic of infection with this strain of E. coli, which resulted in the death of 53 people - explains Piasecki.

Why are enterohaemorrhagic E. coli strains dangerous? Because the Shiga toxin they produce binds to glycolipid receptors present on the surface of endothelial cells, as well as intestinal and kidney epithelium and erythrocytes, leading to the death of cells to which they 'attach' themselves. The source of these bacterial strains is mainly cattle, but also dogs and birds living in cities. What intrigues scientists is the fact that, for example, pigeons are resistant to toxins and do not show any disease symptoms.

- We know that birds have Shiga toxin receptors on erythrocytes and endothelial cells. We know that they even have two types of receptors whose synthesis is controlled by two different genes, whereas in mammals only one gene is responsible for it. We want to investigate why this is happening, because the answer to that question may help us develop methods to prevent complications accompanying infections with this dangerous strain of Escherichia coli – says Tomasz Piasecki.