Supplementary data for the article: Vatić, S.; Mirković, N.; Milošević, J. R.; Jovčić, B.; Polović, N. Đ. Broad Range of Substrate Specificities in Papain and Fig Latex Enzymes Preparations Improve Enumeration of Listeria Monocytogenes. International Journal of Food Microbiology 2020, 334, 108851. https://doi.org/10.1016/j.ijfoodmicro.2020.108851

Supplementary material for: [https://doi.org/10.1016/j.ijfoodmicro.2020.108851]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4090

Supplementary material for the article: Rašković, B.; Vatić, S.; Andelković, B.; Blagojević, V.; Polović, N. Optimizing Storage Conditions to Prevent Cold Denaturation of Trypsin for Sequencing and to Prolong Its Shelf Life. Biochemical Engineering Journal 2016, 105, 168–176. https://doi.org/10.1016/j.bej.2015.09.018

Supplementary material for: [https://doi.org/10.1016/j.bej.2015.09.018]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2024

Broad range of substrate specificities in papain and fig latex enzymes preparations improve enumeration of Listeria monocytogenes

Numerous applications of proteolytic enzymes include dissociation of fermented meat products for the enumeration of `foodborne pathogenic bacteria. The use of trypsin for this cause is abandoned due to the high concentration of the enzyme affecting released bacteria. Papain, as a suggested replacement, and fig latex preparation with high extent of papain-like enzymes have the potential to be applied for bacteria enumeration. Both enzymatic preparations, originating from papaya and fig, showed a broader range of substrate specificities including gelatinolytic activity, especially prominent in the case of ficin and attributed to both, cysteine protease ficin and serine protease by the analysis of 2D zymography with specific inhibitors. The activity towards native collagen, mild in the case of papain, and extensive in the case of fig latex was proved by structural analysis of digested collagen by infrared spectroscopy. Further exploration of their potential for dissociation of fermented meat products showed that both papain and fig latex enzymes are stable in the presence of detergents Tween 20 and Triton X-100 and effective in the enumeration of Listeria monocytogenes. Gelatenolytic activity, and at least partial collagenolytic activity and stability in procedure conditions make papaya and fig latex proteases potent for this application in significantly lower concentrations than previously used enzymes. As a mixture of proteolytic enzymes with divergent characteristics, fig latex preparation shows higher efficiency in Listeria monocytogenes release than papain, conserved even in the presence of stronger non-ionic detergent Triton X-100.Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4091

Trypsin activity and freeze-thaw stability in the presence of ions and non-ionic surfactants

Trypsin is a serine protease with important applications such as protein sequencing and tissue dissociation. Preserving protein structure and its activity during freeze-thawing and prolonging its shelf life is one of the most interesting tasks in biochemistry. In the present study, trypsin cryoprotection was achieved by altering buffer composition. Sodium phosphate buffer at pH 8.0 led to pH shift-induced destabilization of trypsin and formation of a molten globule, followed by significant activity loss (about 70%). Potassium phosphate and ammonium bicarbonate buffers at pH 8.0 were used with up to 90% activity recovery rate after 7 freeze-thaw cycles. The addition of non-ionic surfactants Tween 20 and Tween 80 led to up to 99% activity recovery rate. Amide I region changes, corresponding to specific secondary structures in the Fourier transform infrared (FTIR) spectrum, were modest in the case of Tween 20 and Tween 80. On the other hand, the addition of Triton X-100 led to the destabilization of α-helicoidal segments of trypsin structure after 7 freeze-thaw cycles but also increased protein substrate availability

Optimizing storage conditions to prevent cold denaturation of trypsin for sequencing and to prolong its shelf life

Trypsin is a serine protease with widespread applications, including protein sequencing and typsin mass fingerprinting. In the present study, the storage of trypsin in acidic conditions significantly affected the recovery of activity (40%) after 7 freeze-thaw cycles. Further, trypsin lost parts of its native secondary structure elements, which resulted in a 10% increase in beta-sheet content (band maximum detected at a frequency of 1634 cm in the Fourier transform infrared (FT-IR) spectrum) indicative of freezing-induced denaturation of the protein. The cold storage of trypsin in ammonium bicarbonate (pH 8.2) with the addition of ayoprotectants, such as glycerol or lysine, led to protein stabilization (complete secondary structure content preservation was detected by FT-IR), higher activity recovery ( gt 90%) and modest autolysis ( lt 10%). High activity recovery ( gt 90%) was also detected with the addition of propylene glycol and polyethylene glycol, saccharides and arginine. Nevertheless, trypsin stored at pH 8.2 with the addition of glycerol or lysine was as efficient as untreated trypsin in the trypsin mass fingerprinting analysis of BSA, suggesting that the cold storage of trypsin in slightly alkaline conditions with the addition of cryoprotectants could prolong its shelf life. (C) 2015 Elsevier B.V. All rights reserved.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3586

Antimicrobial assesment of aroylhydrazone derivatives in vitro

Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N′-(2-hydroxy-phenylmethylidene)-3-pyridinecarbohydrazide (2), N′-(5-chloro-2-hydroxyphenyl-methylidene)-3-pyridinecarbohydrazide (10), N′-(3,5-chloro-2-hydroxyphenylmethylidene)-3-pyridinecarbohydrazide (11), and N′-(2-hydroxy-5-nitrophenylmethylidene)-3-pyridinecarbohydrazide (12) showed antibacterial activity against Escherichia coli, with MIC values (in µmol mL−1) of 0.18–0.23, 0.11–0.20, 0.16–0.17 and 0.35–0.37, resp. Compounds 11 and 12, as well as N′-(2-hydroxy-3-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (6) and N′-(2-hydroxy-5- methoxyphenylmethylidene)-3-pyridinecarbohydrazide (8) showed antibacterial activity against Staphylococcus aureus, with the lowest MIC values of 0.005–0.2, 0.05–0.12, 0.06–0.48 and 0.17–0.99 µmol mL−1. N′-(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (7) showed antifungal activity against both fluconazole resistant and susceptible C. albicans strains with IC90 range of 0.18–0.1 µmol mL−1. Only compound 11 showed activity against C. albicans ATCC 10231 comparable to the activity of nystatin (the lowest MIC 4.0 ×10−2vs. 1.7 × 10−2 µmol mL−1). Good activity regarding multi-resistant clinical strains was observed for compound 12 against MRSA strain (MIC 0.02 µmol mL−1) and compounds 2, 6 and 12 against ESBL+ E. coli MFBF 12794, with the lowest MIC for compound 12 (IC50 0.16 µmol mL−1). Anti-biofilm activity was found for compounds 2 (MBFIC 0.015–0.02 µmol mL−1 against MRSA) and 12 (MBFIC 0.013 µmol mL−1 against EBSL+ E. coli). In the case of compound 2 against MRSA biofilm formation, MBFIC values were comparable to those of gentamicin sulphate, whereas in the case of compound 12 and EBSL+ E. coli even more favourable activity compared to gentamicin was observed

Antimicrobial assesment of aroylhydrazone derivatives in vitro

Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N-(2-hydroxy-phenylmethylidene)-3-pyridinecarbohydrazide (2), N-(5-chloro-2-hydroxyphenyl-methylidene)-3-pyridinecarbohydrazide (10), N-(3,5-chloro-2-hydroxyphenylmethylidene)-3-pyridinecarbohydrazide (11), and N-(2-hydroxy-5-nitrophenylmethylidene)-3-pyridinecarbohydrazide (12) showed antibacterial activity against Escherichia coli, with MIC values (in µmol mL–1) of 0.18–0.23, 0.11–0.20, 0.16–0.17 and 0.35–0.37, resp. Compounds 11 and 12, as well as N-(2-hydroxy-3-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (6) and N-(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (8) showed antibacterial activity against Staphylococcus aureus, with the lowest MIC values of 0.005–0.2, 0.05–0.12, 0.06–0.48 and 0.17–0.99 µmol mL–1. N-(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide (7) showed antifungal activity against both fluconazole resistant and susceptible C. albicans strains with IC90 range of 0.18–0.1 µmol mL–1. Only compound 11 showed activity against C. albicans ATCC 10231 comparable to the activity of nystatin (the lowest MIC 4.0 ×10–2 vs. 1.7 × 10–2 µmol mL–1). Good activity regarding multi-resistant clinical strains was observed for compound 12 against MRSA strain (MIC 0.02 µmol mL–1) and compounds 2, 6 and 12 against ESBL+ E. coli MFBF 12794, with the lowest MIC for compound 12 (IC50 0.16 µmol mL–1). Anti-biofilm activity was found for compounds 2 (MBFIC 0.015–0.02 µmol mL–1 against MRSA) and 12 (MBFIC 0.013 µmol mL–1 against EBSL+ E. coli). In the case of compound 2 against MRSA biofilm formation, MBFIC values were comparable to those of gentamicin sulphate, whereas in the case of compound 12 and EBSL+ E. coli even more favourable activity compared to gentamicin was observed

Isolation, identification, and stability of Ficin 1c isoform from fig latex

Latex of common fig (Ficus carica) is a rich protein source with a high level of proteolytic activity contributing to its defensive role. The divergent group of cysteine proteases known as ficin (EC 3.4.22.3) represents the majority of latex protein content and shows activity towards fig parasites. Both classical and novel biochemical techniques suggest the intricate pattern of ficin expression and activity profiles. Even though structurally related, different ficin isoforms show some differences in pI values enabling their separation using ion-exchangers. A single alkaline isoform was purified and identified based on the available transcriptomic data as Ficin 1c. This isoform shows both general proteolytic and gelatinolytic activity suggesting a biological role in the degradation of a broad range of natural substrates. The insight into the Ficin 1c structure also provided some functional clues. The secondary structure content and the overall fold are similar to related proteases of the same and other plant sources resulting in similar unfolding routes. Stability assessment of Ficin 1c in comparison to ficin isoform mixture showed that isoform diversity might lead to increased protease stability.The peer-reviewed version: [https://cherry.chem.bg.ac.rs/handle/123456789/4265

Novel approach to the measurement of antithyroglobulin antibodies in human serum – application of the quartz crystal microbalance sensors

Measurement of antithyroglobulin antibodies (TgAb) is an inevitable laboratory tool in the management of thyroid gland diseases. Currently available immunoassays still have limitations underlying the necessity of the introduction of fast, sensitive, and label-free technologies. Our aim was to develop a method for TgAb measurement in human serum based on the quartz crystal microbalance (QCM) technology. We immobilized thyroglobulin on the surface of Attana LNB Carboxyl sensor chip®, prepared standard curve covering the range of 1–50000 kIU/L, and established optimal measurement conditions. The validation included determination of the detection limit (LOD), functional sensitivity, linearity, precision, as well as the comparison with the results of the radioimmunoassay (RIA). The LOD and functional sensitivity were 4.2 kIU/L and 4.7 kIU/L, respectively. The method was linear in the range of 20–10000 kIU/L. The regression equation for comparison with RIA was CQCM = 1.0056 • CRIA – 24.2778, whereby no significant proportional or systematic difference was present. There was a good agreement with RIA in the classification of patients according to the clinical significance of the results. The developed method has advantages over currently available assays in terms of better LOQ, a higher upper limit of linearity, and precision. The characteristics of the developed method unambiguously show that the application of the QCM biosensors offers a highly reliable novel approach for the measurement of TgAb in human serum