Prehľad aktuálneho čísla

Preparation and application of molecularly imprinted polymers for chiral HPLC separation of biologically active substances

Chiral separations are one of the important analytical tasks, since there are increasing demands for production of enantiomerically pure compounds. The separation and determination of enantiomers find applications in pharmaceutical and food analysis, and it is necessary to pay attention to the development and improvement of chiral analytical methods. High performance liquid chromatography (HPLC) with chiral stationary phase (CSP) based on molecularly imprinted polymers (MIPs) is perspective way. One of the main advantage of these stationary phases is the possibility of predetermining the elution order of enantiomers. The presented work is focused on the methods of preparation and the applications of selective sorption materials (MIPs) in the field of HPLC separation of biologically active substances, amino acids. This review contains comprehensive informations about MIP-amino acid synthesis: compositions of polymerization mixture (monomer, template, cross-linker, porogen), type of polymerization and polymerization conditions, what can affect final efficiency of enantioseparation. The most used porogen was toluene, crosslinker ethylene glycol dimethacrylate (EDMA) and initiator azoisobutyronitrile (AIBN). MIP CSP prepared for derivatized amino acids show better results (higher resolution) than MIP prepared for underivatized amino acids. MIPs are very promising material to be used as stationary phase in HPLC, although further developments and new approaches are necessary to fully exploit their potential.

Keywords: Amino acids, Enantiomers, HPLC, Chiral stationary phase, Molecularly imprinted polymers

Biosafety of genetically modified wheat (Triticum aestivum) Hi-line 111

Mohamed Abd-Elfattah Mohamed Hassan, Rafaat Mohamed Elsanhoty, Mohamed Fawzy Ramadan, Mohyeldeen Ali Osman

Genetically modified (GM) crops were approved for edible use in several countries but their biosafety for organisms remains to be crucial. The objectives of this work were to compare GM wheat (Triticum aestivum) Hi-line 111 (GMW) with native non-GMW wheat (NGMW) to find differences, if any, in their biosafety. Three groups of albino rats (Rattus norvegicus) were used to study the biosafety of GMW for 30 days. Group 1 was fed on a basal diet (control), and group 2 on a control diet with 30 % replacement of starch with NGMW, while group 3 was fed on the control diet with 30 % replacement of starch with GMW. There were no significant signs of adverse impacts noted in the clinical appearance of animals fed on GMW in terms of initial body weight, absolute or relative organ weights and serum profile in comparison with the control group. However, slight histopathological changes were observed in the organs of animals fed on GMW. Though our results demonstrate GMW biosafety regarding its biochemical parameters, however, detailed description of submucosal edema and further studies on allergenic potential with long feeding periods should be performed to conclude its impacts on health.

Keywords: Genetic modification, GMO, Histopathology rats, Safety assessment, Serum biochemistry, Transgenic wheat

In silico assessment of Rhanterium adpressum sesquiterpenes inhibitory effect on 3 and 15-O-trichothecene acetyltransferases

Fatiha Elhouiti, Djilali Tahri, Mohamed Ouinten , Mohamed Yousfi

Essential oils (EO) from leaves and flowers of Rhanterium adpressum have shown to inhibit the mycelial growth and type B trichothecenes production. The four strains of Fusarium culmorum and Fusarium graminearum were inhibited with 0.25 μL.mL-1 of each oil. The inhibitory activity of 11 sesquiterpenes identified in these oils was here examined in silico against two key enzymes in the biosynthesis pathway of trichotecenes namely: 15-O-trichothecene acetyltransferase and 3-O-trichothecene acetyltransferase. In sesquiterpene composition, T-Muurolol and α-Eudesmol have the highest percentages ranging from 1.4 to 2.75 %. Three-dimensional structures of these two enzymes were modeled using SWISS-MODEL with GMQE = 0.93 and QMEAN = -0.45 for 3-O-trichothecene acetyltransferase and GMQE = 0.93, QMEAN = -0.58 for 15-O-trichothecene acetyltransferase. By the results of docking, T-Muurolol and α-Eudesmol showed high affinity compared to 15-Decalonectrin and Deoxynivalenol. These molecules are all sesquiterpenes with no major conformational difference with an RMSD of 3.7 Å and 3.5 Å between 15-decalonectrin and α-Eudesmol, T-Muurolol respectively. The results of docking prove the inhibitory effect of R. adpressum EO sesquiterpenes on the enzymes of mycotoxins biosynthesis pathway of F. culmorum and F. graminearum.

Keywords: 15-O-trichothecene acetyltransferase, 3-O-trichothecene acetyltransferase, Docking, Homology modeling, Rhanterium adpressum

In silico study of anticarcinogenic potential of the selenoprotein BthD from Drosophila melanogaster. Identifying the anticancer peptide CRSUR from the conserved region

Toluwase Hezekiah Fatoki, Omodele Ibraheem, Amos Olalekan Abolaji, David Morakinyo Sanni

Drosophila melanogaster is used as a model system in biomedical studies. Selenoprotein is the major biological form of selenium in eukaryotes. Selenoproteins are generally involved in catabolic pathways in bacteria and archaea, whereas it participates in anabolic and antioxidant processes in eukaryotic. In this study, anticancer potential of selenoprotein BthD of D. melanogaster was investigated using bioinformatics methods. Results showed that selenoprotein BthD of D. melanogaster may have dual properties as evident by its orthology with selenoprotein H (SelH) of Homo sapiens and conserved domain of fructokinase-like protein 2 of Vitis vinifera. These dual properties were also revealed in the phylogenetic analysis, while further structural modeling showed that selenoprotein BthD possibly exists as homotetramer in the native functional structure. The anticancer property of selenoprotein BthD was proposed to be by synergy of antioxidant or redox activities of thioredoxin and glutathione reductase (TGR) domain and the signaling function of fructokinase-like protein 2 domain both in Golgi apparatus and cytoplasm, through energy deprivation. The anticancer peptide CRSUR was identified from conserved region of selenoprotein BthD, of which its cyclic form showed potential anticancer properties predictively through E3 ubiquitin-protein ligase regulating NF-kappa-B signaling by unleashing cells for spontaneous formation of the ripoptosome.

Keywords: Anticancer peptide, Drosophila melanogaster, Mechanism design, NF-kappa-B signaling, Selenoprotein BthD

A sequence-dependent classification algorithm for Crohn's Disease - causing NOD2 protein mutations

Jose Isagani B. Janairo, Marianne Linley L. Sy-Janairo

Certain NOD2 protein mutations have been associated with the onset of the inflammatory bowel disease, Crohn's Disease (CD). NOD2 is involved in the inflammatory response of the gut to the microbial community, wherein its functional impairment through mutations may lead to CD progression. Considering the significant role that NOD2 plays in CD pathogenesis, predicting whether a specific type of NOD2 mutation is the cause of CD can greatly aid the accuracy of the disease diagnosis. Hence, a novel sequence-based classification algorithm built on artificial neural network (ANN) is herein presented that can predict whether a specific NOD2 mutation can cause CD or not. The NOD2 mutant types and their association with CD were taken from literature, and the calculated sequence-order coupling numbers were used as the classification predictors. The formulated ANN classifier exhibited satisfactory predictive ability, with 82.4 % accuracy, 62.5 % sensitivity, 100 % specificity, 100 % positive predictive value, and 75 % negative predictive value. The presented ANN classifier provides a proof-of-concept that predicting the onset of CD from NOD2 protein variant is possible.

Keywords: Artificial neural networks, Inflammatory bowel disease, Machine learning, Personalized medicine

Comparative chemical composition of seeds of amaranth varieties introduced in Uzbekistan

Shuhratjon S. Olimjonov, Jamolitdin F. Ziyavitdinov, Soyibjon S. Bozorov, Uchqun J. Ishimov, Nodir Sh. Berdiev, Nadjiya N. Abrekova, Muydinjon M. Muminov, Akmal M. Asrorov

Amaranth is one of ancient cultured plants possessing valuable food quality that is still important in modern agriculture. In this work, we studied the seed chemical compositions of four plant varieties of Amaranthus cruentus and Amaranthus hypochondriacus species, acclimatized in Uzbekistan. Quantity of free amino acids, amino acids compositions of proteins, vitamins, oligo- and polysaccharides were established using chemical and physical methods. Our results on protein content suggest that introduction of these varieties into eco-climate of Andijan region, Uzbekistan, was not very favorable, though proteins resembled up to 9.4 - 13.4 % (w/w) of seed biomass. Of the water-soluble vitamins tested, the vitamin B1 was most abundant (0.81 - 1.14 µg.g-1 of seed) with significant differences among the acclimatized varieties. Impact of feeding rats with seeds flour of studied Helios variety was established. Blood levels of triglycerides, high-, low- and very low-density lipoproteins, catalase activity under hyperlipidemia were analyzed. We found Helios variety seed flour, possibly because of high saccharides content, significantly lowered the levels of total cholesterol (-26 %) and low-density lipoproteins (-21 %). The acclimatized varieties were identified as potentially valuable food source possessing antihyperlipidemic property.

Keywords: Amaranth varieties, Free amino acids, Oiliness, Saccharides, Total amino acids, Vitamins

Variable accumulation of cadmium in flax (Linum usitatissimum L.)

Mária Pavlovičová, Zuzana Gerši, Monika Bardáčová, Petra Ranušová, Miroslav Horník, Ildikó Matušíková

Given the potential use of flax in metal-contaminated soil remediation programs, the uptake and accumulation of cadmium was studied in five varieties of flax (Linum usitatissimum L.) including var. Belinka, Escalina, Jitka, Marina and Krasnoder. Early stage plants in hydroponics were exposed to Cd to assess their tolerance by means of growth parameters and content of photosynthetic pigments. All varieties exerted tolerance indexes in the range of 63 - 89 %, while oxidative stress was not detected in either variety. Chitinase enzymes were analyzed in leaf protein extracts since activities of these enzymes have previously been correlated with plant tolerance to Cd. However, total enzyme activities remained unchanged in presence of Cd in all flax varieties. A more detailed analysis of these enzymes identified up to 3 chitinase isoforms upon separation of leaf protein extracts in polyacrylamide gels, and their quantification confirmed responsiveness to Cd for each of them. The obtained data were interpreted in light of metal uptake rate, which we measured using gammaspectrometry in growth media spiked with 109Cd and in the plant tissue. The variety Jitka showed the most sensitive to Cd and accumulating fast and the highest amounts of metal. In contrast, the variety Belinka appeared most tolerant, accumulating the least Cd in a slow rate. Activation of chitinase isoforms correlated with more sensitive varieties and suggests activation of general defense mechanisms. The obtained data suggest the variety Jitka as most promising for phytoremediation programs and the var. Belinka as the most suitable when avoidance of potential health risk is of interest.

Keywords: Hyperaccumulators, Metal accumulation, Metal stress, PR proteins

Molecular characterization and evaluation of crude oil remediation potential of some rhizobia isolated from plant root nodules

Jesupemi Mercy Enibukun, Bolatito Esther Boboye

This study aimed to determine the molecular identities and genetic relatedness of rhizobia isolated from pigeon pea and pinto beans, and assess their remediation potential in the presence of 1 %, 3 % and 5 % (w/v) crude oil in minimal medium for 7 days incubation period. Standard microbiological and molecular methods which include amplification and purification of 16S rRNA, agarose gel electrophoresis, and sequencing. Results showed molecular identities of six rhizobia from pigeon peas as Bradyrhizobium diazoefficiens USDA122, Rhizobium leguminosarum WSM2304, Bradyrhizobium japonicum N61, Rhizobium leguminosarum N741, Rhizobium leguminosarum BIHIB1217, and Bradyrhizobium japonicum E109; and three rhizobia obtained from pinto beans were Rhizobium leguminosarum N871, Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium japonicum SEMIA5079. All tested rhizobia (9) showed petroleum degradation ability, as they all grew in the 1, 3 and 5 % (w/v) crude oil minimal medium under laboratory conditions. B. diazoefficiens USDA122 showed the highest optical density (OD) value of 1.184 ± 0.05 on 7th day at 1 % (w/v) crude oil contamination, while R. leguminosarum N741 has the lowest OD value of 0.372 ± 0.02 at 5 % (w/v) crude oil on 7th day. For all the rhizobia, increase occurred throughout incubation period at 1, 3 and 5 % (w/v) except Rhizobium leguminosarum N741 and R. leguminosarum BIHIB1217. In conclusion, the association of R. leguminosarum BIHIB1217 and R. leguminosarum N871 from pigeon pea and pinto beans respectively, were found most effective in crude oil degradation and thus they are recommended as a promising association for remediation of crude oil spilled soils.

Keywords: Bioremediation, Cajanus cajan, Crude oil pollution, Molecular characterization, Phaseolus vulgaris, Rhizobia

Perspective pretreatment method of beech and poplar wood and wheat straw in 2G biofuel production processing

Andrej Pažitný, Albert Russ, Štefan Boháček, Štefan Šutý, Vladimír Ihnát

Monosaccharides such as glucose, xylose and arabinose are the main monomer units of which cellulose and hemicelluloses are composed. The cellulose and hemicelluloses content in many biomass species makes them suitable for 2G bioethanol production. Today, when 1G bioethanol production is closely monitored due to its enormous consumption of food raw materials such as wheat or corn grains, larger companies are gradually moving to pilot operations of 2G bioethanol production. However, cellulose and hemicelluloses contained in biomass are only very slightly accessible to enzymes used in 2G bioethanol production. Therefore pretreatment methods such as steam explosion are very suitable to use for fractionation of cell structure. In this paper, we tested the cellulose accessibility. We compared the cellulose accessibility of wheat straw particles with wooden particles obtained from beech and poplar. Particle size was less than 0.7 mm. We identified the optimal conditions of steam explosion pretreatment at reaction temperature of 200 °C for wheat straw, poplar and beech wood particles. The main indicator of accessibility was concentration of monomers obtained from enzymatic hydrolysis. The concentration of monomer was determined by high performance liquid chromatography. The experimental results showed different accessibility measure for each type of biomass species.

Keywords: Beech wood, Cellulose accessibility, Enzymatic hydrolysis, Poplar wood, Steam explosion pretreatment, Wheat straw

Factors affecting the analysis of 2-deoxy-2-fluoro[18F]-D-glucose in plant tissues by a commercial PET system

Vanda Adamcová, Klára Kuglerová, Katarína Ondreičková, Marcela Gubišová, Jozef Gubiš, Juraj Lesný, Peter Kováč, Miroslav Horník

Some works showed that commercial PET systems and 2-deoxy-2-fluoro[18F]-D-glucose (2-[18F]FDG) can be used in plant studies to analyze the transport and allocation of photoassimilates. The aim of this work was to evaluate the effect of characteristics of plant tissues, applied solution and the phenomenon of "escaping positrons" on the visualisation and quantification of the uptake and distribution

Keywords: 2-[18F]FDG, PET, Plant tissues, Uptake, Quantification, 3D imaging

Hydrogen atom disorder in the crystal structure of o-phenylenediacetic acid

Lenka Krešáková, Juraj Kuchár, Juraj Černák

H2opda (1) (o-phenylenediacetic acid) was prepared in the form of single crystals. It exhibits molecular crystal structure. The main feature of the supramolecular structure of 1 is formation of hydrogen bonded dimers via a pair of O-H×××O hydrogen bonds. The hydrogen atoms in COOH groups are disordered in 0.67(2):0.33(2) ratio. The conformation of the free acid is characterized by cis arrangement of the carboxylate groups with respect to the plane of the aromatic ring. The powder diffraction pattern of the bulk sample corroborated the phase identity of the commercial material with that of the studied single crystal.

Keywords: o-phenylenediacetic acid, Crystal structure, Hydrogen atom disorder, Hydrogen bonded dimer

Citizen science based monitoring of microbial water quality at a single household level in a South African local municipality during the COVID19 lockdown

Roman Tandlich

Personal hygiene and access to potable water, which is safe for human consumption, are critical to containing the COVID19 pandemic. Here monitoring results are reported for microbial quality of water samples from the municipal supply in Makana Local Municipality in the Eastern Cape Province, South Africa. Access of the human population to sufficient volumes of potable water of required (microbial) quality has been a problem in this local municipality. Samples were taken just before and during 30 days of the strictest phase of the nation-wide lockdown, related to COVID19 in South Africa. Aim of this short communication was to perform the water quality testing with limited to no access to laboratory facilities and using the principles of citizen science. The H2S test kit was used as the basis for the microbial testing, while a cell phone app was used for the temperature monitoring. Five H2S test kit were used per sampling at the author's house and the kits was developed for the microbial water quality assessment in isolated settings such as those for the lockdown. During the study, the ambient temperature ranged from 17 to 29 °C, with decreases below 18 °C occurring on three out of 12 sampling occasions. Thus the results of the H2S test kit might have been slightly influenced by the fluctuations of the ambient temperature. On 8 sampling occasions between 1 and 4 H2S test kits were positive for faecal contamination. Three samples or 25 % were free of faecal contamination. One sample had all five H2S test kits were positive for faecal contamination. Results of statistical testing indicated that potable water in Makana Local Municipality was probably microbially contaminated at the author's household on an intermittent basis. Ongoing monitoring of microbial drinking water quality is necessary and continuing at the sampled location.

Keywords: Drinking/potable water, Hygiene, H2S test kit, MMakana Local Municipality, Pandemic