Publications
2009
I. Gutiérrez-Aguirre, M. Banjac, A. Steyer, M. Poljšak-Prijatelj, M. Peterka, A. Štrancar, M. Ravnikar
Journal of Chromatography A, 1216 (2009) 2700–2704
Rotaviruses are the leading cause of diarrhoea in infants around the globe and, under certain conditions they can be present in drinking water sources and systems. Ingestion of 10–100 viral particles is enough to cause disease, emphasizing the need for sensitive diagnostic methods. In this study we have optimized the concentration of rotavirus particles using methacrylate monolithic chromatographic supports. Different surface chemistries and mobile phases were tested. A strong anion exchanger and phosphate buffer (pH 7) resulted in the highest recoveries after elution of the bound virus with 1 M NaCl. Using this approach, rotavirus particles spiked in 1 l volumes of tap or river water were efficiently concentrated. The developed concentration method in combination with a real time quantitative polymerase chain reaction assay detected rotavirus concentrations as low as 100 rotavirus particles/ml.
2008
F. Smrekar, M. Ciringer, M. Peterka, A. Podgornik, A. Štrancar
Journal of Chromatography B, (2007)
Phages are gaining importance due to their wide usage. In this work strong anion exchange monolithic chromatographic column was used for single step phage purification. Most of the proteins and DNA were removed and recovery of approximately 70% of infective virus was reproducibly achieved. 30 ml of phage sample was purified in around 10 min.
I. V. Kalashnikova, N. D. Ivanova, T. B. Tennikova
Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 5, pp. 867-873
A simple virus-cell complementary model system can be obtained using polymer-analogous reactions of the epoxy groups of glycidyl methacrylate-ethylene glycol dimethacrylate monolithic macroporous polymeric support and of the carboxy groups of styrene-methyl methacrylate polymeric nanospheres. The effect of thus designed microenvironment on the affinity binding parameters of virus-mimicking nanoparticles with the functionalized sorbent surface is studied by high-performance monolithic disk affinity chromatography.
S. Likić, G. Rusak, M. Krajačić
Journal of Chromatography A, 1189 (2008) 451–455
High-performance liquid chromatography was developed for further separation of double-stranded (ds) RNAs obtained by CF-11 cellulose chromatography from plants infected with satellite associated cucumber mosaic virus. Fractions separated by monolithic polymer column, especially applicable for nucleic acid analyses, were identified electrophoretically and confirmed with a polymerase chain reaction test. Once standardized, the method has revealed clear evidence of satellite presence without precipitation and electrophoresis. According to demonstrated sensitivity, its application in the preliminary diagnostics of field samples is also predictable. Principally, it can be used as a powerful preparative approach resulting in highly pure satellite dsRNA for further analyses.
2007
E. Müller, C. Mann
Journal of Chromatography A, 1144 (2007) 30-39(2007) 30-39
The electro-acoustic effects, namely the ion vibration potential (IVP) and the colloidal vibration current (CVI), colloidal vibration potential (CVP) first described by P. Debye [P. Debye, J. Chem. Phys. 1 (1933) 13], are a result of charge separation of bound or free ions at different degrees by ultrasonic waves. Today commercial instruments are available to investigate liquid homogeneous and heterogeneous systems. In the present paper the application of this technique for the characterization of salts, protein solutions and resins for biochromatography is shown and valuable information about resins can be derived in a short time. Various resins were investigated with the following results: (1) the CVI magnitude is dependent of several parameters (such as particle size distribution, volume fraction, density difference); (2) the CVI is influenced by the surface modification of the resins. Polymeric modifications decrease the value of CVI. The CVI is generally lower for high capacity resins; (3) the measurement of the electro-acoustic effects can be used to detect small changes in resins. The CVI is dependent of the amount of adsorbed protein in “native” and denatured state.
P. Kramberger, M. Peterka, J. Boben, M. Ravnikar, A. Štrancar
Journal of Chromatography A, 1144 (2007), pg. 143–149
Drawbacks of conventional virus purification methods have led to the development of new, mostly chromatography-based methods. Short monolithic columns are stationary phases intended for purification of large molecules. In this work efficient chromatographic purification of tomato mosaic virus (ToMV) from plant material is described. Based on short monolithic column, the purification process was shortened from 5 days to 2 hours. High viral purity was achieved and recovery of chromatographic step was up to 90%. In addition, these columns enabled preliminary quantification of the virus in just a few minutes, much faster than other quantification methods (e.g. enzyme-linked immunosorbent assay or real-time polymerase chain reaction) which take 1–2 days. These results demonstrate the potential of short monolith column technology for purification and analysis of different viruses.
J. Boben, P. Kramberger, N. Petrovič, K. Cankar, M. Peterka, A. Štrancar, M. Ravnikar
European Journal of Plant Pathology (2007) 118:59-71
A quantitative RT real-time PCR method was developed for the detection and quantification of Tomato mosaic virus (ToMV) in irrigation waters. These have rarely been monitored for the presence of plant pathogenic viruses, mostly due to the lack of efficient and sensitive detection methods. The newly developed method presented here offers a novel approach in monitoring the health status of environmental waters. ToMV was reliably detected at as low as 12 viral particles per real-time PCR reaction, which corresponds to the initial concentration of approximately 4.2 × 10-10 mg (6,300 viral particles) of ToMV per ml of sample. The sensitivity of the method was further improved by including the Convective Interaction Media® (CIM) monolithic chromatographic columns for quick and efficient concentration of original water samples. Seven out of nine water sources from different locations in Slovenia tested positive for ToMV, after concentrating the sample. Four samples tested ToMV-positive without the concentrating procedure. The presence and integrity of infective ToMV particles in the original sample, as well as in the chromatographic fraction, was confirmed using different methods from test plants, DAS ELISA to electron microscopy and real-time PCR. In this study, we propose a unique and simple diagnostic scheme for rapid, efficient, and sensitive monitoring of irrigation waters that could also be adopted for other plant, human or animal viruses.
M. Peterka, D. Glover, P. Kramberger, M. Banjac, A. Podgornik, M. Barut, A. Štrancar
BioProcessing Journal, March/April 2005
The last 30 years have seen rapid and dramatic developments in recombinant DNA technology and the related biological sciences. In 1972, Paul Berg's group used restriction enzymes to cut DNA in half and then used ligases to stick the pieces of the DNA back together. By doing this, they produced the first recombinant DNA. Within a year, the first genetically engineered bacterium existed. A little more than ten years later, recombinant human insulin was approved for diabetic patients and became the first recombinant healthcare product. Before the end of the 1980s, the first gene therapy trial had occurred. Today, a large number of recombinant proteins are used as marketed drugs and even more are in clinical trials targeting a wide range of diseases.
2005
M. Peterka, P. Kramberger, A. Štrancar
WANG, Perry G. (ur.). Monolithic chromatography and its modern applications. St Albans: ILM publications, 2010, pg. 489-508
Downstream processing (DSP) for purification can become a significant bottleneck in the production of novel biotherapeutics, such as viral vectors and vaccines (viral or DNA). Although different techniques can be used for the purification of large molecules and particles, liquid chromatography is the preferred method as it achieves the purity required by regulatory agencies. Despite the popularity of conventional chromatographic media, the diffusional mass transfer of large molecules and relatively small pore size remain limiting factors for the efficient separation of large biomolecules and particles. Methacrylate monoliths are a single-piece chromatographic support that consists of a highly porous material with an interconnected network of channels. The transport mechanism is predominantly based on convection, which allows rapid mass transfer between the mobile and stationary phase and so results in short separation times. Additionally, most of the active sites are located in the open, large channel structure and are therefore easily accessible, which results in a high DBC (DBC) for large molecules and viral particles. These characteristics make methacrylate monoliths an ideal chromatographic support for the separation and purification of extremely large molecules, such as large proteins, different types of DNA and virus particles.
2004
P. Kramberger, N. Petrovič, A. Štrancar, M. Ravnikar
Journal of Virological Methods 120 (2004) 51-57120 (2004) 51-57
A new chromatographic medium, Convective Interaction Media® (CIM) disk monolithic columns, was applied to plant virus concentration. The ability of the columns to concentrate highly diluted plant viruses was tested on a model plant virus, rod-shaped tomato mosaic virus (ToMV). Enzyme-linked immunosorbent assay (ELISA) was used for the quantitative analysis. The virus was concentrated using a strong anion exchanger, CIM quaternary amine (QA) disk monolithic column. A high salt concentration was used to elute the concentrated virus from the columns. It has been demonstrated that ToMV, which had been diluted considerably below the sensitivity of ELISA, was concentrated by several orders of magnitude in the one-step procedure. Concentrated virus preparations could be used directly for ELISA testing. In comparison with methods described for concentrating plant viruses from irrigation water, the above procedure may provide a much faster and more efficient way to concentrate highly diluted plant viruses. The procedure could be applied to the testing of other highly diluted plant viruses, and to concentrating viruses for antiserum production.
P. N. Nesterenko, M. A. Rybalko
Mendeleev Commun. 2004
The continuous flow gradient and its effect on chromatographic parameters were investigated for the separations of inorganic anions on a monolithic porous disk with bonded hydroxyproline residues.
2003
E. G. Vlakh, G. A. Platonova, G. P. Vlasov, C. Kasper, A. Tappe, G. Kretzmer, T. B. Tennikova
Journal of Chromatography A, 992 (2003) 109–119
The recently discovered serine protease called tissue plasminogen activator (t-PA) enables efficient dissolution of blood clots. t-PA works by converting plasminogen into its active form, plasmin, dissolving the major component of blood clots, fibrin. The activation of plasminogen by t-PA is enhanced by the presence of fibrin, and this is probably due to the fact that both plasminogen and t-PA possess high affinity binding sites for fibrin. Besides fibrin, fibrin monomers and some fibrin(ogen) degradation products, certain synthetic polymers (for instance, poly-l-lysines) can provide the same stimulation of plasminogen activation. The recently developed high-performance monolithic-disk chromatography, HPMDC, could become the most convenient way to study biological pairs of interest. The inherent speed of HPMDC isolation facilitates the recovery of a biologically active product, since the exposure to putative denaturing influences, such as solvents or temperature, is reduced. The better mass transfer mechanism (convection rather than diffusion) allows to consider only the biospecific reaction as time limiting. The step-by-step modeling of hypothetical affinity pairs between t-PA and different types of oligo/polymer forms of linear and branched lysine derivatives obtained both by initiated polycondensation and solid-phase peptide synthesis using HPMDC seemed to be possible and a quite useful tool. The results of quantitative evaluation of such affinity interactions were compared with those established for natural affinity counterparts to t-PA (monoclonal antibodies, plasminogen, fibrinogen). The role of steric structure of lysine ligands was observed and analyzed. The results allowing to make the practical choice of affinity systems will be used for development of fast and efficient analytical and preparative methods for the downstream processes of recombinant production of this valuable enzyme.
P. Kramberger, D. Glover, A. Štrancar
American Biotechnology Laboratory, 2003, 21(13), 27-8.
Research in molecular and cell biology has shown that macromolecules such as pDNA and virus vectors, together called nanoparticles, have the potential to assist in the prevention and treatment of some human diseases. The most important step in their production is the downstream processing (isolation and cleaning). Precipitation, ultrafiltration, and LC techniques are the most widely used for these purposes, but only LC can purify the product so that it is recognized as safe for therapeutic use. Apart from reduced yield, downstream processing can cause minor or even major modifications in the structure of the biomolecule. Usually these modifications do not affect the activity of the product, but may change its antigenicity. Minimizing these changes to maintain product safety is the main objective in the downstream processing of nanoparticles. For the efficient isolation of labile biomolecules, liquid chromatographic supports should provide fast and efficient separation in order to decrease biomolecule degradation; have high, preferably flow-unaffected capacity and resolution; and exhibit low backpressure. They should be stable, even if harsh conditions are applied during sanitation (e.g., 1 M NaOH), and should be easy to handle and operate. CIM® (Convection Interaction Media) monolithic chromatographic columns (BIA Separations, Ljubljana, Slovenia) meet all of these requirements. This article will discuss the columns and their use on human models and plant viruses and pDNA.
2001
P. Svete, R. Milačič, B. Mitrović, B. Pihlar
The Royal Society of Chemistry 2001, Analyst, 2001, 126, 1346–1354
Analytical procedures were developed for the speciation of Zn using fast protein liquid chromatography (FPLC), flame atomic absorption spectrometry (FAAS) and convective interaction media (CIM) fast monolithic chromatography with FAAS and electrospray (ES)-MS-MS detection. The investigation was performed on synthetic solutions (2 µg cm-3 Zn) of hydrated Zn2+ species and Zn complexes with citrate, oxalate and EDTA (ligand-to-Zn molar ratio 100 : 1) over a pH range from 5.4 to 7.4. It was found that Zn interacts with various buffers and the careful adjustment of the pH with diluted solutions of KOH is, therefore, required. FPLC separations were carried out on a Mono Q HR 5/5 strong anion-exchange column, applying an aqueous 1 mol dm-3 NH4NO3 linear gradient elution over 15 min, at a flow rate of 1.0 cm3 min−1. The separated Zn species were determined in 1.0 cm3 eluate fractions “off line” by FAAS. Speciation of Zn was also performed on a weak anion-exchange CIM DEAE fast monolithic disc by applying an aqueous 0.4 mol dm-3 NH4NO3 linear gradient elution over 7.5 min, at a flow rate of 2.0 cm3 min−1 and determination of the separated Zn species in 1.0 cm3 eluate fractions “off line” by FAAS. Zn-binding ligands in separated fractions were also characterized by electrospray (ES)-MS-MS analysis. The CIM DEAE disc was found to be more efficient in the separation of negatively charged Zn complexes than the Mono Q FPLC column. On the CIM DEAE disc Zn–citrate was separated from both Zn–oxalate and from Zn–EDTA. All these species were also separated from hydrated Zn2+, which was eluted with the solvent front. This method has an advantage over commonly used analytical techniques for the speciation of Zn which are only able to distinguish between labile and strong Zn complexes. Good repeatability of the measurements (RSD 2–4%), tested for six parallel determinations (2 µg cm-3 Zn) of Zn–EDTA, Zn–citrate and Zn–oxalate was found at a pH of 6.4 on a CIM DAEA disc. The limit of detection (3s) for the separated Zn species was 10 ng cm-3. The proposed analytical procedure was applied to the speciation of Zn in aqueous soil extracts and industrial waste water from a lead and zinc mining area.