Merih Kivanç

The hydrodistilled essential oil of Echinophora tenuifolia L. subsp. sibthorpiana commonly known as “çörtük,” “tarhana grass,” or “pickle grass” was evaluated for its antimicrobial activity against 17 microorganisms (16 bacteria and Candida albicans) by using microdilution and bioautography methods. Methyl eugenol (38.8%), δ-3-carene (31.2%) and p-cymene (9.0%) were determined by GC-FID and GC/MS systems as main constituents of the essential oil. The oil showed strong inhibitory effects, particularly against the plant pathogens Xanthomonas campestris and X. campestris pv. phaseoli with minimum inhibitory concentrations (MIC) of 62.5 and 31.25 µg/mL, respectively. Candida albicans was inhibited by the oil at 500 µg/mL. According to the results of TLC-bioautography assay, methyl eugenol and δ-3-carene were identified as the compounds responsible for antimicrobial activity. These bioactive compounds were further tested with the essential oil at the same time against certain pathogens for the determination of possible synergistic effects.

In recent years, mini screws used in the mouth have been widely used in orthodontics clinics to provide dental movements and to increase skeletal anchorage. In this study, bacteria were isolated from mini screws taken from patients who were treated in the Orthodontic Department of Eskişehir Osmangazi University Faculty of Dentistry Clinic and routinely applied mini screws to the anterior and posterior regions of the upper palate for jaw widening or support of dental movements. Streptococcus salivarus (15 isolates), Streptococcus anginosus (12 isolates) and Enterococcus feacalis (10 isolates) were the most isolated bacteria in the microbial composition. Rothia mucilaginosa (8 isolates) and Corynebacteria argentoratense (6 isolates) were isolated from the Actinobacteria phylum. Neisseria oralis, N. flava, N. subflava and N. flavescens species were determined from Proteobacteria phylum.

To investigate the antiproliferative properties of exopolysaccharides (EPS) on human colorectal adenocarcinoma cell line (Caco-2) and the regulation of MUC5AC gene expression, the antiproliferative effect of EPS isolated from D36 strain was determined by MTT test and the regulation of MUC5AC gene expression was examined using Real-Time PCR. Enterococcus faecium D36 (E. faecium D36) were characterized by Ribotyping analysis. Some biochemical methodologies were preliminarily used to characterize the probiotic potential of E. faecium D36, including morphological, cultural, and physiological characteristics. EPS isolated from E. faecium D36 strain has an antiproliferative effect on Caco-2 cell line, and mucin gene (MUC5AC) expression levels decreased. These results suggest that EPS isolated from E. faecium D36 strain might be a source for a novel anticancer agent. Based on our results, it is believed that EPS obtained from E. faecium D36 can be used as a protective and therapeutic substance during the early stages of cancer, especially colon cancer. EPS affects colon cancer by reducing the invasion ability of cancer by decreasing MUC5AC expression. These findings are thought to shed light on future in vivo studies.

In recent years, the concept of postbiotics has gained significant attention in the field of food and nutrition. Postbiotics are non-viable microbial products or metabolic byproducts generated during the fermentation of probiotics. These compounds, which include organic acids, peptides, and polysaccharides, have demonstrated numerous health benefits. This comprehensive perspective explores the emerging science of postbiotics, their mechanisms of action, and their diverse applications in food and nutrition. Drawing on recent research and clinical studies, this review highlights the potential of postbiotics to revolutionize functional foods, dietary supplements, and personalized nutrition strategies. 1

Bu çalışmada ceviz (Juglans regia) yapraklarının su, etil asetat ve metanol ekstrelerinin antibiyofilm aktivitesi araştırılmıştır. Ekstrelerin antimikrobiyel ve antibiyofilm aktivitesi Pseudomonas aeruginosa, Klebsiella pneumoniae, Aeromonas hydrophila ve Salmonella enterica, Staphylococcus warneri, Staphylococcus capitis, Staphylococcus aureus, Enterococcus faecium, E. faecalis, Listeria monocytogenes Serovar I, L. monocytogenes 19111, L. monocytogenes 4b 19115, L. ivanovii 19119, L. innocua 6a 33090, Streptococcus mutans, S. anginosus, Bacillus cereus, Bacillus safensis ve B. mojavensis’a karşı araştırılmıştır. Bütün ekstrelerinin S. mutans (1a103), S. mutans (2a7) ve S. aureus (GMC7) üzerinde antimikrobiyel aktivitesinin olmadığı diğer bakteriler üzerinde ise farklı oranlarda etki gösterdikleri belirlenmiştir. Su ekstresinin %99.20 metanol ekstresinin %95.05 ve etil asetat ekstresinin ise %95.22 oranlarına varan antibiyofilm etkilerinin olduğu tespit edilmiştir. Ekstrelerin biyofilm oluşumunu azaltmada oluşmuş biyofilmi gideriminden daha etkili oldukları tespit edilmiştir. Ayrıca en yüksek antioksidan aktiviteye etil asetat aktivitesinin sahip olduğu belirlenmiştir.

Amaç: Bu çalışmanın amacı probiyotik laktik asit bakterilerine ait hücresiz filtratların göz yüzeyinden izole edilmiş olan Listeria monocytogenes, Pseudomonas putida, Pseudomonas stutzeri, Stenotrophomonas maltophilia ve Staphyloccocus epidermidis’in ürettikleri biyofilm üzerine antibiyofilm aktivitesinin araştırılmasıdır. Materyal-Metot: Laktik asit bakterileri olarak Lactobacillus rhamnosus 1743, Lactobacillus plantarum1771, Lactobacillus rhamnosus 3111, L. rhamnosus KA1 ve L. rhamnosus 1724 kullanıldı. Kullanılmadan önce hem laktik asit bakterilerinin hem test bakterilerinin saflıkları kontrol edildi. Laktik asit bakterileri hücresiz filtratları 22µm’lik filtreden geçirildi. Hücresiz filtratın antibiyofilm etkisi için TSB ortamında kültüre edilen test bakterileri kuyucuklara dağıtıldı. Kuyucuklar yıkandıktan sonra 570 nm’de spektrofotometrik olarak optik yoğunluğa göre biyofilm oluşumu değerlendirildi. Bulgular: Laktik asit bakterilerinden elde edilen hücresiz filtratların farklı test bakterilerinde farklı oranlarda biyofilm oluşumunu inhibe ettiği gözlendi. L. rhamnosus KA1’in hücresiz filtratı test edilen tüm bakterilerin biyofilmlerini ortalama en fazla azaltan filtrattı. Laktik asit bakterilerinin filtratlarının biyofilmi en çok azalttıkları test bakterisi P. stutzeri 23 CZPX olarak tespit edildi. Sonuç: Probiyotik laktik asit bakterilerinden elde edilen hücresiz filtratlar bakterilerin oluşturduğu biyofilmlerin önlenmesinde yardımcı olabilir. Farklı LAB hücresiz filtratlarının farklı test bakterilerinin oluşturduğu biyofilme etkileri değişebilmektedir. Geniş spekturumlu bir LAB hücresiz filtratın tespiti ve etkinliği için ileri çalışmalara ihtiyaç vardır.

The current study was carried out to investigate metabolic activities and main probiotic characteristics of two Latilactobacillus sakei strains (8.P1 and 28.P2) isolated from pastırma, a highly seasoned, air-dried cured beef. Both strains showed antimicrobial activity against important foodborne pathogens like Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa and so forth. For the characterization of antimicrobial activity, the effect of various enzymes, temperature and pH were tested. The results of the tests demonstrated that the antimicrobial activity of strains was based on the production of protein-structured compounds such as bacteriocin or bacteriocin like peptides. In metabolic activity studies, amounts of the lactic acid, proteolytic activity and hydrogen peroxide produced by the 8.P1 and 28.P2 were found to range between 16.09 and 17.32 mg/mL, 0.24 and 0.04 mg/mL and 0.98 and 0.04 µg/mL, respectively. It was also observed that neither strain could produce exopolysaccharide. Both strains were found susceptible to vancomycin, chloramphenicol, gentamicin, tetracycline, and netilmicin sulfate. When the strains are evaluated with respect to their probiotic potential, 28.P2 could tolerate acidic conditions, but 8.P1 showed sensitivity. The survival rate of the strains in the simulated gastric juice and their adhesion abilities were found suitable to stay alive in the gastrointestinal tract and to proliferate in the intestine. The evaluation of all the features of both strains demonstrated that both strains had the potential to be used as a protective culture. In addition, it was observed that 8.P1 and 28.P2 were more suitable as a starter culture and a probiotic candidate respectively.

Heavy metal pollution is an serious environmental problem because they have toxic effects on living organisms. In recent years, the use of microbial biosorbents to remove heavy metal pollution have studied. Many biological materials are used to remove copper ions. In this study, the biosorption capacity of lyophilized Pantoea agglomerans for Cu (II) ions were investigated under various conditions (initial pH, contact time, initial heavy metals ion concentration). The monocomponent biosorption data have been analyzed using isotherm (Freundlich and Langmuir) and kinetic models. The highest copper uptake capacity of the biomass was obtained at the initial copper concentration of 250 mgL-1 at pH 5.0 and contact time 90th minute. The equilibrium data correlated well with the Langmuir and Freundlich model. It was found that the pseudo-second-order kinetic model fitted the experimentally obtained data. Liyofilized P. agglomerans biomass appears to be an inexpensive and efficient biosorbent for the removal of Cu (II) from aqueous solutions.

Con las tecnologías verdes se eliminan los daños que ocasionan los desechos agrotecnológicos al medio ambiente. En nuestro estudio, el objetivo era prevenir el daño de los residuos de aceite de oliva al medio ambiente y producir la enzima lipasa, que es un producto biotecnológico importante. E. faecium E68 obtenido de leche y productos lácteos se utilizó en la producción de la enzima lipasa. E. faeciumE68 se desarrolló en medio de producción de lipasa con un 10% de orujo de aceituna, pH 6,5, a 37 ^oC con agitación a 120 rpm durante 48 h. También se determinó el efecto de la temperatura, el pH del ion metálico, el surfactante y el NaCl. El peso molecular de la enzima lipasa extracelular parcialmente purificada se estimó en alrededor de 19-20 kDa mediante SDS-PAGE. La temperatura óptima fue de 45 °C, mientras que la enzima exhibió una termoestabilidad apreciable reteniendo la actividad a 55°C durante 48 h. La actividad óptima de la lipasa fue a pH10. Los iones 1mM, Ca ²⁺, Mn²⁺, Cu²⁺, Ni²⁺, Zn²⁺, Mg²⁺ y K⁺ modularon la actividad de la enzima pero fueron inhibidos por Hg^2+, SDS y Triton X-100. La enzima es halófila y la sal de NaCl al 25% aumentó la actividad.