Browsing by Author "Nemska V."
Now showing 1 - 18 of 18
Results Per Page
Sort Options
Item Antimicrobial activity of (KLAKLAK)–NH2 analogs against pathogenic microbial strains(2024-01-01) Jaber S.; Evstatieva Y.; Nemska V.; Nikolova D.; Naydenova E.; Georgieva N.; Danalev D.Many microorganisms pose a threat to human health due to the ever-increasing bacterial resistance to conventional drugs. Nowadays, searching for new alternatives to conventional antibiotics to fight bacterial resistance is a main task. Thus, natural molecules such as amino acids and peptides arise as possible solutions to the problem. The antimicrobial activity of targeted compounds was studied by the agar-diffusion method, using the prepared working solutions of the targeted peptides with the corresponding concentrations. The results of the antimicrobial activity against different test pathogens show specificity, as antimicrobial activity against the used test microorganisms was not found in the investigated short-chain synthetic peptides Si6, Si3 and Si13. Antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes, Escherichia coli, Pseudomonas aeruginosa, and the yeasts Malassezia furfur and Candida albicans was established for the long-chain synthetic peptides Si1, Si5 and Si16, except Si5 which does not show activity against pathogenic fungal strain C. albicans. The compound Si16 where natural Leu in (KLAKLAK)2-NH2 is replaced by unnatural Nle is the best candidate for medical drug due to the combined antibacterial and antiproliferative effect as well as long hydrolytic stability.Item ANTIMICROBIAL ACTIVITY OF AMINO ACID DERIVATIVES OF MEMANTINE(2022-01-01) Tencheva A.; Stankova I.; Angelova T.; Nemska V.; Georgieva N.; Danalev D.Memantine is adamantane derivative used in medicinal practice. It is well-proven inhibitors of the M2 ion channel of influenza virus. In addition, it is applied for treatment of patients with Alzheimer’s disease. Herein, we report the antimicrobial activity of specifically designed memantine derivatives containing spatially compact (Gly, Ala, β-Ala) and bulky (Val and Phe) amino acids. New compounds were synthesized in a solution using 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate (TBTU) as a coupling agent. All derivatives were obtained with good yields. Newly synthesized molecules at concentration 100 mM were tested for their antimicrobial activity using model strains of Gram-positive (Bacillus subtilis NBIMCC 3562), Gram-negative (Escherichia coli NBIMCC K12 407) microorganisms and fungal strain Candida albicans NBIMCC 74. The active compounds against model G+ microorganism are Val-MEM followed by Ala-MEM and Gly-MEM. All compounds show good activity against model G-microorganism. Introducing of bulky amino acid Phe, containing aromatic core, and Val, containing aliphatic core, leads to good antifungal activityItem ANTIMICROBIAL PROFILE OF EXTRACTS FROM THE FUNGUS SPECIES LEPISTA PERSONATA(2023-01-01) Nemska V.; Yaneva S.; Georgieva N.; Danalev D.Nowadays, mushrooms are widely studied due to the various bioactive substances they produce. They define their antibacterial, antifungal, antioxidant, antitumor, cytostatic and anti-inflammatory properties which are beneficial for human health. This study aimed to determine the antimicrobial activity of different (hot and cold ethanol/ dichloromethane/ hexane) extracts from the fungus species Lepista personata against two test microorganisms: Escherichia coli NBIMCC K12 407 and Bacillus subtilis NBIMCC 3562. The antimicrobial assays were performed applying the classical disc diffusion method. The sensitivity of test microorganisms was determined according to the zone of inhibition which appeared around the discs after 24 h of incubation at 30°C - 37°C. All extracts were dissolved in 200 mM dimethyl sulfoxide, which was used as a control sample. Results showed that E. coli NBIMCC K12 407 is susceptible to dimethyl sulfoxide whereas B. subtilis NBIMCC 3562 showed no growth inhibition. All mushroom extracts also showed no inhibitory activity against B. subtilis NBIMCC 3562. At the same time, only the dichloromethane extract obtained after hot extraction inhibited the growth of E. coli NBIMCC K12 407.Item Development and validation of HPLC-DAD methodology for simultaneous qualitative and quantitative determination of thirteen substances with a steroid structure(2023-01-01) Zaharieva Z.; Atanasova S.; Danalev D.; Jaber S.; Foteva T.; Nemska V.; Tanev D.; Georgieva N.Using supplements in different sports is a common practice for many athletes. Unfortunately, the growth of this market has entailed some speculations, such as the addition of excessive doses of potentially toxic ingredients. Sometimes the doses listed on the package do not correspond to the real content. Some nutritional supplements on sale may contain undeclared ingredients. Some of those supplements are prohibited substances according to different regulations. Herein, a simple HPLC/DAD procedure that is easy to apply in conventional laboratory practice was developed for the simultaneous determination of 13 substances with steroid structure in nutritional supplements for sport: testosterone, testosterone propionate, testosterone enanthate, methyltestosterone, nandrolone, nandrolone propionate, nandrolone decanoate, methandienone, androstenedione, trenbolone, trenbolone acetate, trenbolone enanthate and boldenone undecylenate. The methodology includes gradient elution with mobile phase A: MeOH:ddH2O (55:45) and mobile phase B: 100% MeOH in a standard HPLC system containing a Halo 90 Å, C18 (150 x 4.6 mm, 2.7 µm) column, flow rate 0.6 mL/min, UV wavelength of 254 nm, temperature of 40 °C and 20 μL injection volume. The developed methodology was validated according to the corresponding official documents. The key parameters used for the selection of the optimal HPLC conditions were the ability of the mobile phase and solvents to be used with both an HPLC/MS and a GC/MS chromatographic system. The obtained total run time, the reproducibility of the retention times, the separation of all peaks and peak characteristics meet all requirements.Item Effect of B2O3 on the Structure, Properties and Antibacterial Abilities of Sol-Gel-Derived TiO2/TeO2/B2O3 Powders(2023-10-01) Bachvarova-Nedelcheva A.; Iordanova R.; Stoyanova A.; Georgieva N.; Nemska V.; Foteva T.This paper studies the influence of B2O3 on the structure, properties and antibacterial abilities of sol-gel-derived TiO2/TeO2/B2O3 powders. Titanium(IV) butoxide, telluric(VI) acid and boric acid were used as precursors. Differences were observed in the degree of decomposition of Ti butoxide in the presence of H3BO3 and H6TeO6 acids. The phase transformations of the obtained gels in the temperature range of 200–700 °C were investigated by XRD. Composite materials containing an amorphous phase and different crystalline phases (metallic Te, α-TeO2, anatase, rutile and TiTe3O8) were prepared. Heating at 400 °C indicated a crystalline-to-amorphous-phase ratio of approximately 3:1. The scanning electron microscopy (SEM) analysis showed the preparation of plate-like TiO2 nanoparticles. The IR results showed that the short-range order of the amorphous phases that are part of the composite materials consists of TiO6, BO3, BO4 and TeO4 structural units. Free B2O3 was not detected in the investigated compositions which could be related to the better connectivity between the building units as compared to binary TiO2/B2O3 compositions. The UV-Vis spectra of the investigated gels exhibited a red shift of the cut-off due to the presence of boron and tellurium units. The binary sample achieved the maximum photodegradation efficiency (94%) toward Malachite green dye under UV irradiation, whereas the ternary sample photoactivity was very low. The compositions exhibited promising antibacterial activity against E. coli NBIMCC K12 407.Item Enzyme profile of lactobacilli from traditional Bulgarian fermented milk products(2019-01-01) Nemska V.; Danova S.; Georgieva N.In recent years, scientific community has focused the attention on the non-starter lactic acid microbiota of home-made dairy products as a source of new candidate-probiotic strains. Lactic acid bacteria (LAB) and in particular Lactobacillus spp. play a major role in acquiring the specific taste and aroma of the final product during the fermentation. For this purpose, 43 Lactobacillus strains, isolated from traditional Bulgarian katak, curd, yoghurt, white-brined and yellow cheese, were subjected to screening of their enzyme capacity. Twenty-five of the strains were pre-selected for determination of their enzyme profile by API ZYM system. It was established that most of the strains showed high leucine and valine arylamidase, β-galactosidase and α-glucosidase activity. Only a few strains showed N-acetyl-β-glucosaminidase, α-galactosidase, β-glucosidase and Naphtol-AS-BI-phospho-hydrolase activity. Alkaline phosphatase, trypsin, α-chymotrypsin, α-mannosidase, lipase (except L. lactis OC2), β-glucuronidase (except L. salicinus KC2) and α-fucosidase (except L. plantarum BS41 and L. lactis OC2) activity were not observed. In order to complete the obtained results, two qualitative tests for determination of the β-galactosidase and proteolytic activity of more than 30 Lactobacillus strains were also applied. Most of the investigated lactobacilli showed moderate proteolytic activity. According to their β-galactosidase activity, 34 % could be defined as active lactose fermenters, 23 %-as late lactose fermenters and 43 %-could not ferment lactose. The investigated Lactobacillus strains showed strain-specific enzyme capacity.Item Functional characteristics of lactobacilli from traditional bulgarian fermented milk products(2019-01-01) Nemska V.; Logar P.; Rasheva T.; Sholeva Z.; Georgieva N.; Danova S.After oral administration, probiotic lactobacilli meet a number of protection systems in the human body, such as exposure to gastric, pancreatic, and small intestinal juices. Overcoming these detrimental barriers allows living bacteria to adhere to the intestinal epithelium and permanently colonize the gastrointestinal tract (GIT), providing health benefits to the host. Based on this, the transit tolerance of 25 candidate probiotic lactobacilli from katak, yoghurt, and white-brined and yellow cheese to simulated bile and small intestinal juices of variable pH was investigated. To establish their resistance, in vitro model systems based on modified MRS media and a longer duration of action (up to 24 h of incubation) were designed. Six of the strains studied were found to show strain-specific survival capacity with low viability in conditions simulating stomach acidity and high resistance to bile and intestinal juices. In addition, the adherence capability (autoaggregation and hydrophobicity) of the strains was determined. Obtained results allowed to select Lactobacillus strains with high survival ratios while passing through the GIT and good adherence properties, which make them suitable for the development of new probiotics.Item IN VITRO ASSESSMENT OF LACTOBACILLUS SPP. TO GROW IN THE PRESENCE OF DIFFERENT CARBON SOURCES IN THE MEDIUM(2022-01-01) Nemska V.; Danova S.; Georgieva N.The selection of suitable media plays a central role in attempts to improve the production of biomass from lactobacilli and the yield of products during fermentation. For this purpose, the growth capacity of 41 candidate probiotic lactobacilli from katak, yoghurt and white-brined and yellow cheese in the presence of different carbon sources in the medium was investigated. To access their abilities, in vitro model systems based on modified MRS broth, containing different carbon sources (2 % and 5 % (w/v) lactose or 2 % (w/v) glucose, prebiotics (inulin, galactooligosaccharides, glucooligosaccharides and fructooligosaccharides) and 30 % (w/v) sucrose) were designed. It was established that Lactiplantibacillus plantarum S8 and S10 had the highest growth rate in modified MRS with 2 % (w/v) glucose, whereas Lactobacillus delbrueckii subsp. bulgaricus Ro34 showed the highest growth rate in modified MRS broth with 5 % (w/v) lactose. In the presence of modified MRS, containing 20 % (w/v) prebiotics, most Lactobacillus strains showed complete utilisation towards galactooligosaccharides, followed by inulin, fructooligosaccharides and glucooligosaccharides. Seventy-three per cent of strains could grow in the presence of 30 % (w/v) sucrose in the medium and were determined as possible exopolysaccharide producers. In addition, the biofilm-formation capacity of the lactobacilli, cultivated in these media, was tested. Lactiplantibacillus plantarum OC1 and BS32 demonstrated good biofilm-formation in the presence of galactooligosaccharides, whereas Ligilactobacillus salivarius subsp. salicinus KC2 formed stable biofilms in the presence of galactooligosaccharides and fructooligosaccharides.Item INFLUENCE OF Nb2O5 AND B2O3 ON THE PHOTOCATALYTIC AND ANTIBACTERIAL ACTIVITY OF SOL-GEL DERIVED TiO2 NANOPОWDERS(2024-01-01) Bachvarova-Nedelcheva A.; Iordanova R.; Georgieva N.; Nemska V.; Foteva T.; Stoyanova A.TiO2 based powders containing B2O3 and Nb2O5 were obtained through an aqueous sol-gel method. The as-prepared gels were step wisely heated in the temperature range 200°C - 500°C and subsequently characterized by XRD, IR and UV-Vis analysis. The TiO2 (anatase) is the single crystalline phase which has been detected up to 500°C. Photocatalytic tests showed that the investigated samples possess photocatalytic activity toward Malachite green organic dye and TiO2/Nb2O5 exhibited higher photocatalytic activity than TiO2/B2O3 sample. The compositions exhibited good antimicrobial activity against E. coli NBIMCC K12 407 and Bacillus subtilis NBIMCC 3562.Item Lactobacillus spp. from traditional Bulgarian dairy products(2016-01-01) Nemska V.; Lazarova N.; Georgieva N.; Danova S.Over the last few years the traditional dairy products have been gaining much more popularity among scientists and consumers. They are a part of the nutritional diet of people since ancient times and are a proven source of lactic acid bacteria (LAB) with confirmed and beneficial effects on human health. LAB are the main cause of lactic acid fermentation and determine the specific properties of the resulting products. Home-made fermented dairy products are a part of the daily diet and tradition is saved in several rural regions of Bulgaria. However, the beneficial microbiota of some of them is poorly characterized. Therefore, any research aimed at the isolation and identification of LAB from traditional foods helps to define the autochthonous microbiota, which is typical for the area/product. With these aims 26 artisanal samples of 4 types Bulgarian dairy products: yoghurt, white-brined cheese, yellow cheese and curd, were collected. Their lactic microflora was studied and 74 pure cultures were isolated. They were identified as Lactobacillus spp. using classical approaches for identification. For this reason further characterization of the created collection of lactobacilli is considered perspective.Item Microbiological, Physico-chemical and Rheological Evaluation of Yoghurts, Fermented with Lactobacilli from Traditional Bulgarian Dairy Products(2021-01-01) Nemska V.; Karsheva M.; Danova S.; Georgieva N.Recently the consumers’ demand for new fermented milk products, combining ingredients with natural origin, good quality and beneficial health effects, increase more and more. For this reason, it is very important to pay particular attention to the strains used as starter cultures or additives during their production. The aim of this study is to investigate the dynamic changes in microbiological, physicochemical and rheological properties of milk, fermented with 9 candidate probiotic lactobacilli during their storage. The influence of 21 days of storage on the microbial count, pH, titratable acidity, lactic acid concentration and rheological parameters was determined. Most fermented milk samples demonstrated high cell viability of the starters used, combined with a slight decrease in pH and a corresponding increase of the titratable acidity during the fermentation process. These parameters remain relatively stable during storage. The rheological tests showed that the fermented milk samples studied demonstrated non-Newtonian behavior, which could be described with Herschel-Bulkley rheological model. The results obtained allowed to select lactobacilli with desired properties: high microbial count, a slight change in the physicochemical properties and a non-Newtonian behavior. The data of this study could be used for the development of new fermented milk products with functional properties.Item PHOTOCATALYTIC AND ANTIBACTERIAL ASSESSMENT OF SOL - GEL DERIVED TiO2/TeO2/ZnO POWDERS(2022-01-01) Bachvarova-Nedelcheva A.; Iordanova R.; Georgieva N.; Nemska V.; Stoyanova A.Two ternary gel compositions containing simultaneously TiO2, TeO2 and ZnO were selected for detailed investigations. The phase transformations of the gels upon the heating were investigated by XRD analysis and it was established that the obtained composites contain an amorphous phase and different crystalline phases: TiO2 (anatase), TiO2 (rutile), a-TeO2 and ZnTeO3, depending on composition. The IR results showed that the short range order of the amorphous phases which are part of the composite materials consist of TiO6, ZnO4 and TeO4 structural units. By UV-Vis spectroscopy was measured the absorption edge of the gels which is about 363 nm and the calculated Eg values are about 3.41 eV. The performed photocatalytic tests showed that the samples possess photocatalytic activity toward Malachite green organic dye. Both compositions exhibited good antimicrobial activity against E. coli K12.Item Sol-Gel Obtaining of TiO2/TeO2 Nanopowders with Biocidal and Environmental Applications(2023-02-01) Bachvarova-Nedelcheva A.; Iordanova R.; Naydenov A.; Stoyanova A.; Georgieva N.; Nemska V.; Foteva T.TiO2/TeO2 powders were obtained by an aqueous sol-gel method. Telluric acid (H6TeO6) and titanium butoxide were used as precursors. The as-prepared gel was step-wisely heated in the temperature range 200–700 °C and subsequently characterized by XRD, IR, and UV-Vis analysis and SEM. Mixtures containing TiO2 (anatase), α-TeO2 (paratellurite), and TiTe3O8 were established by XRD as final products, depending on heating temperature. The thermal stability of the obtained gels in the temperature range 100–400 °C was investigated. It was found by IR spectroscopy that the samples heated up to 300–400 °C consist mainly of an organic–inorganic amorphous phase which is transformed into an inorganic one above these temperatures. The microstructure of the gels was verified by scanning electron microscopy (SEM). The photocatalytic degradation of the synthesized nanopowders toward Malachite green organic dye (MG) was examined in order to evaluate the potential applications for environmental remediation. The prepared TiO2/TeO2 samples showed up to 60% decoloration efficiency after 120 min exposure to UV-light. The composition exhibited good antimicrobial activity against E. coli K12. The properties of the obtained material were investigated by the reactions of complete catalytic oxidation of different alkanes and toluene, and it could be suggested that TiO2/TeO2 powders are promising material for use as an active phase in environmental catalysts.Item Synthesis and Biological Studies of New Temporin A Analogs Containing Unnatural Amino Acids in Position 7(2024-06-01) Dimitrova D.; Nemska V.; Foteva T.; Iliev I.; Georgieva N.; Danalev D.(1) Background: Antimicrobial resistance is growing at an extreme pace and has proven to be an urgent topic, for research into alternative treatments. Such a prospective possibility is hidden in antimicrobial peptides because of their low to no toxicity, effectiveness at low concentrations, and most importantly their ability to be used for multiple treatments. This work was focused on the study of the effect of the modification in position 7 of Temporin A on its biological activity; (2) Methods: The targeted peptides were synthesized using Fmoc/Ot-Bu SPPS. The antibacterial activity of the analogs was determined using the broth microdilution method and disk-diffusion method. In vitro tests were performed to determine the cytotoxicity, phototoxicity, and antiproliferative activity of the peptide analogs on a panel of tumor and normal cell lines; (3) Results: All analogs except DTCit showed good antibacterial activity, with DTDab having the best activity according to the disk-diffusion method. However, DTCit had an acceptable cytotoxicity, combined with good selectivity against the test MCF-7 cell line; (4) Conclusions: The obtained results revealed the importance of the basicity and length of the side chain at position 7 in the Temporin A sequence for both tested activities.Item Synthesis and biological studies on (KLAKLAK)2-NH2 analog containing unnatural amino acid β-ala and conjugates with second pharmacophore(2021-12-01) Jaber S.; Nemska V.; Iliev I.; Ivanova E.; Foteva T.; Georgieva N.; Givechev I.; Naydenova E.; Karadjova V.; Danalev D.(1) Background: Peptides are good candidates for anticancer drugs due to their natural existence in the body and lack of secondary effects. (KLAKLAK)2 is an antimicrobial peptide that also shows good anticancer properties. (2) Methods: The Solid Phase Peptide Synthesis (Fmoc-strategy) was used for the synthesis of target molecules, analogs of (KLAKLAK)2-NH2. The purity of all compounds was monitored by HPLC, and their structures were proven using mass spectrometry. Cytotoxicity and antiproliferative effects were studied using 3T3 NRU and MTT tests, respectively. For determination of antimicrobial activity, the disc-diffusion method was used. Hydrolytic stability at three pH values, which mimic the physiological pH in the body, was investigated by means of the HPLC technique. (3) Results: A good selective index against MCF-7 tumor cell lines, combined with good cytotoxicity and antiproliferative properties, was revealed for conjugates NphtG-(KLAKLAK)2-NH2 and Caf-(KLAKLAK)2-NH2. The same compounds showed very good antifungal properties and complete hydrolytic stability for 72 h. The compound Caf-(KLβ-AKLβ-AK)2-NH2 containing β-Ala in its structures exhibited good antimicrobial activity against Escherichia coli K12 407 and Bacillus subtilis 3562, in combination with very good antiproliferative and cytotoxic properties, as well as hydrolytic stability. (4) Conclusions: The obtained results reveal that all synthesized conjugates could be useful for medical practice as anticancer or antimicrobial agents.Item Synthesis, antiproliferative and antimicrobial activities of (KLAKLAK)2-NH2 analogue containing nor-Leu and its conjugates with a second pharmacophore(2023-01-01) Jaber S.; Nemska V.; Iliev I.; Ivanova E.; Foteva T.; Georgieva N.; Givechev I.; Tanev D.; Naydenova E.; Danalev D.Peptides are a promising alternative of conventional medical drugs for the treatment of different diseases because they have no or have very few side effects owing to the natural mechanisms for their elimination. There are a lot of examples of drugs on the pharmaceutical market based on modified amino acids and peptides. Herein, we report the synthesis and studies on the antimicrobial peptide (KLAKLAK)2-NH2 where Leu is replaced by the unnatural amino acid nor-Leu. In addition, a second pharmacophore with well proven anticancer properties is introduced to the peptide moiety. All structures were synthesized by conventional solid phase peptide synthesis. The antiproliferative and antimicrobial activities were studied using MTT-dye reduction assay and disk-diffusion test, respectively. Biological activity assays showed that the introduction of nor-Leu in the primary structure of the parent compound does not lead to an increase in the antiproliferative activity. However, the combination with the second pharmacophore 1,8-naphtalimide in a hybrid structure 1,8-NphtG-(KNleAKNleAK)2-NH2 leads to a significant increase in the antiproliferative properties. The antimicrobial tests showed that all tested compounds exhibit antimicrobial activity. The peptide and the second pharmacophore had a synergistic effect. In combination with complete hydrolytic stability for 72 h in model systems, the compound 1,8-NphtG-(KNleAKNleAK)2-NH2 is the best candidate for a medical drug in the treatment of mammary gland type A adenocarcinoma (MCF-7) in combination with antimicrobial properties.Item Synthesis, antitumor and antibacterial studies of new shortened analogues of (KLAKLAK)2-NH2 and their conjugates containing unnatural amino acids(2021-02-02) Jaber S.; Iliev I.; Angelova T.; Nemska V.; Sulikovska I.; Naydenova E.; Georgieva N.; Givechev I.; Grabchev I.; Danalev D.(1) Background: (KLAKLAK)2 is a representative of the antimicrobial peptide group which also shows good anticancer properties. (2) Methods: Herein, we report synthesis using SPPS and characterization by HPLC/MS of a series of shortened analogues of (KLAKLAK)2. They contain single sequence KLAKLAK as C-terminal amides. In addition, substitution of some natural amino acids with unnatural β-Ala and nor-Leu is realized. In addition, these structures are conjugated with second pharmacophore with well proven anticancer properties 1,8-naphthalimide or caffeic acid. Cytotoxicity, antiproliferative effect and antimicrobial activity of newly synthesized structures were studied. (3) Results: The obtained experimental results reveal significant selective index for substances with common chemical structure KLβAKLβAK-NH2. The antibacterial properties of newly synthesized analogues at two different concentrations 10 μM and 20 μM, were tested against Gram-negative microorganisms Escherichia coli K12 407. Only two of the studied compounds KLAKLAK-NH2 and the one conjugated with second pharmacophore 1,8-naphthalimide and unnatural amino acid nor-Leu showed moderate activity against tested strains at concentration of 20 μM. (4) Conclusions: The obtained results reveal that the introducing of 1,8-naphthalimideGlyand Caf- increase the cytotoxicity and antiproliferative activity of the peptides but not their selectivity. Only two compounds KLAKLAK-NH2 and 1,8-naphthalimideGKnLAKnLAK-NH2 show moderate activity against Escherichia coli K12 at low concentration of 20 μM.Item The influence of nd and sm on the structure and properties of sol-gel-derived tio2 powders(2021-07-01) Bachvarova-Nedelcheva A.; Yordanov S.; Iordanova R.; Stambolova I.; Stoyanova A.; Georgieva N.; Nemska V.TiO2 nanopowders modified by Nd and Sm were prepared using the sol-gel technique. It was found by XRD analysis that the samples containing Sm are amorphous up to 300◦C, while those with Nd preserve a mixed organic-inorganic amorphous structure at higher temperatures (400◦C). The TiO2 (rutile) was not detected up to 700◦C in the presence of both modified oxides. TiO2 (anatase) crystals found at about 400◦C in the Sm-modified sample exhibited an average crystallite size of about 25–30 nm, while doping with Nd resulted in particles of a lower size—5–10 nm. It was established by DTA that organic decomposition is accompanied by significant weight loss occurring in the temperature range 240–350◦C. Photocatalytic tests showed that the samples heated at 500◦C possess photocatalytic activity under UV irradiation toward Malachite green organic dye. Selected compositions exhibited good antimicrobial activity against E. coli K12 and B. subtilis.