Tomasz Twardowski

Biotechnology and the European public

The latest European sample survey of public perceptions of biotechnology reveals widespread opposition to genetically modified (GM) food in much of Europe, but public attitudes to medical and environmental applications remain positive.

Mechanisms of homocysteine toxicity in humans

Summary.Homocysteine, a non-protein amino acid, is an important risk factor for ischemic heart disease and stroke in humans. This review provides an overview of homocysteine influence on endothelium function as well as on protein metabolism with a special respect to posttranslational modification of protein with homocysteine thiolactone. Homocysteine is a pro-thrombotic factor, vasodilation impairing agent, pro-inflammatory factor and endoplasmatic reticulum-stress inducer. Incorporation of Hcy into protein via disulfide or amide linkages (S-homocysteinylation or N-homocysteinylation) affects protein structure and function. Protein N-homocysteinylation causes cellular toxicity and elicits autoimmune response, which may contribute to atherogenesis.

Immunohistochemical detection of N-homocysteinylated proteins in humans and mice.

N-homocysteinylation of epsilon-amino group of protein lysine residues by homocysteine (Hcy) thiolactone has been implicated in vascular disease in humans. We have previously generated polyclonal rabbit anti-N-Hcy-protein IgG antibodies that specifically recognize the Nepsilon-Hcy-Lys epitope on N-homocysteinylated proteins. The present work was undertaken to examine the utility of these antibodies for the immunohistochemical detection of N-homocysteinylated proteins in biological samples. We found that the rabbit antibody specifically detected N-Hcy-protein in a dot-blot assay, that the signal resulting from the reaction of the antibody with N-Hcy-protein depended on the amount of the antigen, and that the sensitivity of the assay was protein-dependent. The rabbit anti-N-Hcy-protein IgG also specifically detected Nepsilon-Hcy-Lys epitopes in human tissues, as shown by positive immunohistochemical staining of myocardium and aorta samples from cardiac surgery patients, and a lack of staining when the antibody was pre-adsorbed with N-Hcy-albumin. We also observed increased immunohistochemical staining for N-Hcy-proteins in aortic lesions from ApoE-/- mice with hyperhomocysteinemia induced by a high methionine diet, relative to ApoE-/- mice fed a control chow diet. In conclusion, polyclonal rabbit anti-N-Hcy-protein antibody can detect and monitor N-homocysteinylated proteins in human and mouse tissues with good sensitivity and specificity.

Uninformed and disinformed society and the GMO market

The EU has a complicated regulatory framework, and this is slowing down the approval process of new genetically modified (GM) crops. Currently, labeling of GM organisms (GMOs) is mandatory in all Member States. However, the USA, in which GMO labeling is not mandatory, continues to lead the production of biotech crops, biopharmaceuticals, biomaterials, and bioenergy.

The effect of lupin alkaloids and ethanol extracts from seeds of Lupinus angustifolius on selected bacterial strains

Summary The following pure alkaloids were isolated from lupin seeds ( L. angustifolius var. Mirela): lupanine, 13-OH-lupanine, angustifoline and a 48 % ethanol extract. They and the commercial sparteine were tested for bacteriostatic effects against pathogenic bacteria, namely, Gram-positive ( Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633) and Gram-negative ( Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853); a strain of Gram-positive Bacillus thuringiensis HD-4 with sporeforming rods, isolated from soil, was also tested. The established bacteriostatic agents, e.g. antibiotics, are active at a concentration 3 to 4 orders of magnitude lower than the tested lupin alkaloids. Therefore a bacteriostatic effect is possible in plants under physiological conditions, but a pharmaceutical application of these products as bacteriostatic agents is rather unlikely. The presented data support the allelopathic function of alkaloids.

Study on iron availability from prepared soybean sprouts using an iron-deficient rat model

During soya seeds germination in FeSO(4) solutions their phytoferritin content is multiplied. Prepared soybean sprouts have been proposed as a safe and easily available source of iron supplementation. The preparation was compared with FeSO(4) and ferritin isolates, using rats with induced iron deficiency anaemia. After the end of the 2-week supplementation experiment, it was observed that no statistically significant differences in haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration existed between those animals supplemented with sprouts enriched in ferritin, ferritin isolate and FeSO(4) and healthy animals forming the control group. Moreover, the examined preparation had a beneficial influence on the recreation of ferritin reserves in both the liver and the blood serum, and also did not induce negative alterations in general growth parameters of animals. Use of an easily obtainable ferritin iron source may be a profitable alternative in supplementation due to its wide availability and food preservative properties.

Direct monitoring of albumin lysine-525 N-homocysteinylation in human serum by liquid chromatography/mass spectrometry

A posttranslational protein modification by homocysteine-thiolactone (N-homocysteinylation) is linked to human vascular and neurodegenerative diseases. Although chemical and immunological methods are available to detect and quantify the extent of protein N-homocysteinylation, the determination of site-specific N-homocysteinylation in vivo remains challenging. Here we describe a liquid chromatography/mass spectrometry method that monitors the extent of N-homocysteinylation at albumin lysine-525 in vivo directly in human serum. Using this method, we found that the extent of lysine-525 N-homocysteinylation was significantly increased in patients with cystathionine beta-synthase deficiency.

The Role of Public Opinion in Shaping Trajectories of Agricultural Biotechnology

Science and technology are not autonomous entities and research trajectories are largely influenced by public opinion. The role of political decisions becomes especially evident in light of rapidly developing new breeding techniques (NBTs) and other genome editing methods for crop improvement. Decisions on how those new techniques should be regulated may not be based entirely on scientific rationale, and even if it is decided that crops produced by NBTs do not fall under the umbrella of genetically modified organisms (GMOs), their commercialization is by no means certain at this time. If and when adopted regulations do not comply with the publics perception of risks, policy makers will find themselves under pressure to ban or restrict the use of the respective products.

Social and legal determinants for the marketing of GM products in Poland

The development of biotechnology is influenced by many factors unique for a specific region. In Poland the lack of legislative solutions (to facilitate the promotion of the inventions) and the public resistance against certain sectors of biotechnology are significant factors limiting any further development. Although, science and technology are the front runners in any innovation, the significance of social and legal aspects is difficult to overestimate. In our opinion those factors are interconnected and crucial for marketing of innovative products, therefore, we indicate and explain the most important issues restraining the implementation of innovative biotechnology in the context of national specificity in Poland.

tRNA-derived short RNAs bind to Saccharomyces cerevisiae ribosomes in a stress-dependent manner and inhibit protein synthesis in vitro

Recently, a number of ribosome-associated non-coding RNAs (rancRNAs) have been discovered in all three domains of life. In our previous studies, we have described several types of rancRNAs in Saccharomyces cerevisiae, derived from many cellular RNAs, including mRNAs, rRNAs, tRNAs and snoRNAs. Here, we present the evidence that the tRNA fragments from simple eukaryotic organism S. cerevisiae directly bind to the ribosomes. Interestingly, rancRNA-tRFs in yeast are derived from both, 5′- and 3′-part of the tRNAs and both types of tRFs associate with the ribosomes in vitro. The location of tRFs within the ribosomes is distinct from classical A- and P-tRNA binding sites. Moreover, 3′-tRFs bind to the distinct site than 5′-tRFs. These interactions are stress dependent and as a consequence, provoke regulation of protein biosynthesis. We observe strong correlation between tRF binding to the ribosomes and inhibition of protein biosynthesis in particular environmental conditions. These results implicate the existence of an ancient and conserved mechanism of translation regulation with the involvement of ribosome-associating tRNA-derived fragments.