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    Actinobacteria with heavy metal tolerance from the Sinop coast: A molecular characterization approach
    (Ege Univ, Fac Fisheries, 2025) Veyisoglu, Aysel; Tatar, Demet; Tokatli, Ali; Duyar, Hunkar Avni
    This study aimed to isolate and molecularly characterize marine actinobacteria tolerant to heavy metals from sediment samples collected from the Meydankap & imath; coast in Sinop, T & uuml;rkiye. Sediment samples were obtained from three different stations and cultured on five selective media, leading to the isolation of 54 actinobacteria strains. The highest isolation efficiency was achieved on R2A and SM3 media. The tolerance of the isolates to heavy metals, including lead (Pb), copper (Cu), zinc (Zn), mercury (Hg), and cadmium (Cd), was tested. The results revealed that all isolates were sensitive to Hg and Cd but exhibited high tolerance to Pb. Twelve isolates, showing the highest resistance to heavy metals, were selected for genomic DNA isolation. The 16S rRNA gene region was amplified using universal primers and sequenced. Sequence analysis identified the isolates as belonging to the genera Streptomyces, Actinomadura, Nocardia and Nonomuraea. The approximately 1500-bp 16S rRNA gene sequences were compared with the EzTaxon database, and the closest species were determined. The obtained sequences were deposited in the GenBank database. The results indicate that marine actinobacteria isolated from polluted sediments of the Black Sea possess significant potential for bioremediation and environmental biotechnology applications due to their resistance mechanisms to heavy metals.
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    Antimicrobial magnetic poly(GMA) microparticles: synthesis, characterization and lysozyme immobilization
    (Walter De Gruyter Gmbh, 2021) Erol, Kadir; Tatar, Demet; Veyisoglu, Aysel; Tokatli, Ali
    Micron-sized magnetic particles currently find a wide range of applications in many areas including biotechnology, biochemistry, colloid sciences and medicine. In this study, magnetic poly(glycidyl methacrylate) microparticles were synthesized by providing a polymerization around Fe(II)-Ni(II) magnetic double salt. Adsorption of lysozyme protein from aqueous systems was studied with these particles. Adsorption studies were performed with changing pH values, variable amount of adsorbent, different interaction times and lysozyme amounts. The adsorption capacity of the particles was investigated, and a value of about 95.6 mg lysozyme/g microparticle was obtained. The enzyme activity of the immobilized lysozyme was examined and found to be more stable and reusable compared to the free enzyme. The immobilized enzyme still showed 80% activity after five runs and managed to maintain 78% of its initial activity at the end of 60 days. Besides, in the antimicrobial analysis study for six different microorganisms, the minimum inhibitory concentration value of lysozyme immobilized particles was calculated as 125 tg/mL like free lysozyme. Finally, the adsorption interaction was found to be compatible with the Langmuir isotherm model. Accordingly, it can be said that magnetic poly(GMA) microparticles are suitable materials for lysozyme immobilization and immobilized lysozyme can be used in biotechnological studies.
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    Determination of Amylolytic and Proteolytic Enzyme Activity Characteristics of Thermophilic Actinobacteria Isolated from Amasya-Terziköy Thermal Spring
    (Istanbul Univ Press, Fac Aquatic Sciences, 2025) Tatar, Demet; Veysioglu, Aysel; Tokatli, Ali; Duyar, Hunkar Avni
    Actinobacteria represent a group of Gram-positive microorganisms characterized by high G+C content and are commonly found in both terrestrial and aquatic ecosystems. These bacteria are notable for their capacity to synthesize a wide range of bioactive compounds, including antibiotics and industrial enzymes. Their ability to withstand extreme environmental conditions allows them to colonize challenging habitats, such as thermal springs. These geothermal environments are critical not only for harboring microbial diversity but also for the discovery of novel bioactive substances with therapeutic potential. This study focused on isolating thermophilic actinobacteria from Terzik & ouml;y Thermal Spring in Amasya, T & uuml;rkiye, followed by phylogenetic analysis through 16S rRNA gene sequencing. The enzymatic capacities of the isolates-specifically amylase and protease production-were also assessed. Fourteen of the 21 isolates underwent 16S rRNA sequencing, resulting in the identification of eight Streptomyces, four Nocardia, one Actinomadura, and one Pseudonocardia species. Among these, seven isolates demonstrated amylase activity, and one displayed protease production. Notably, one Streptomyces isolate exhibited both enzymatic activities. These results highlightthe phylogenetic diversity ofthermophilic actinobacteria in geothermal environments and their potential as sources of thermostable enzymes for industrial applications.
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    Streptomyces boluensissp. nov., isolated from lake sediment
    (Springer, 2020) Tokatli, Ali; Idil, Onder; Veyisoglu, Aysel; Saygin, Hayrettin; Guven, Kiymet; Cetin, Demet; Sahin, Nevzat
    A novel Gram-stain positive, aerobic, non-motile actinobacterium, designated strain YC537(T), was isolated from lake sediment collected from Yenicaga Lake, Bolu, Turkey, and subjected to a polyphasic taxonomic approach. The organism had phylogenetic, chemotaxonomic, cultural and morphological properties consistent with its classification in the genusStreptomyces. 16S rRNA gene sequence analysis of strain YC537(T)showed that it is closely related to the type strain ofStreptomyces ziwulingensisF22(T)(97.9% sequence similarity),Streptomyces tauricusJCM 4837( T)(97.7%) andStreptomyces beijiangensisNBRC 100044( T)(97.6%). The cell wall of the strain containedLL-diaminopimelic acid and the cell-wall sugars were glucose, galactose and ribose. The major phospholipids of strain YC537(T)were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The predominant menaquinones were identified as MK-9(H-6) and MK-9(H-8). The major cellular fatty acids wereiso-C-16:0,iso-C-14:0,anteiso-C(15:0)andiso-C-15:0. Consequently, strain YC537(T)is considered to represent a novel species in the genusStreptomyces, for which the nameStreptomyces boluensissp. nov. is proposed. The type strain is YC537(T)(= KCTC 39750( T) = DSM 102303( T)).
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    Streptomyces coryli sp. nov., isolated from hazelnut orchard soil
    (Microbiology Soc, 2020) Saygin, Hayrettin; Veyisoglu, Aysel; Tatar, Demet; Nigiz, Cengiz; Tokatli, Ali; Sahin, Nevzat
    A novel actinobacteria, isolate A7024(T), was isolated from commercial hazelnut orchard soil sample which was collected at Duzce, West Black Sea region, Turkey. A polyphasic taxonomic study was carried out to determine the status of this isolate. The phylogenetic tree reconstructed using the neighbour-joining algorithm based on 165 rRNA gene sequences indicated that isolate A7024(T) was positioned within the members of the genus Streptomyces with the highest sequence similarity (97.7%) to Streptomyces cadmiisoli ZFG47(T). The organism formed an extensively branched substrate and aerial hyphae which generated irregular rod-shaped spores with smooth-surfaces. The cell wall of strain A7024(T) contained LL-diaminopimelic. Glucose, mannose and ribose were detected as whole-cell sugars. Its polar lipids were diphosphatidylglycerol. phosphatidylethanol-amine, phosphatidylinositol, three unidentified phospholipids and three unidentified glycolipids. Major menaquinones were MK-9(H-6) and MK-9(H-4). The major cellular fatty acids were iso-C-16:0, anteiso-C-1(5:0) and anteiso-C-1(7:)0. Strain A7024(T) had a genome size of 9.0 Mb with a genome G+C content of 71.5 mol%. The low level of 16S rRNA gene similarity, 19.3 +/- 2.3% digital DNA-DNA-hybridization and 76.94% average nucleotide identity values, as well as some different phenotypic characteristics allowed the strain to be distinguished from the closely related type strains. Therefore, it is concluded that strain A7024(T) represents a novel species of the genus of Streptomyces, for which the name Streptomyces coryli sp. nov. is proposed. The type strain is A7024(T) (=DSM 42066(T)=KCTC 29102(T)=NRRL B-24888(T)).
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    Whole Genome Sequence-Based Classification of Nonomuraea marmarensis sp. nov., Isolated from Island Soil
    (Mdpi, 2025) Topkara, Ahmet Ridvan; Saygin, Hayrettin; Saricaoglu, Salih; Veyisoglu, Aysel; Tokatli, Ali; Guven, Kiymet; Cetin, Demet
    Actinomycetes are known to produce a vast array of bioactive secondary metabolites with potential therapeutic applications, including antimicrobials, anticancer agents, and enzyme inhibitors. Among these, members of the genus Nonomuraea have received much attention due to their broad ecological importance in nutrient cycling in soil and their ability to produce new bioactive compounds. A novel actinomycetes, designated strain M3C6T, was isolated from soil samples collected on Marmara Island, located in the Istanbul province, aiming to explore the microbial diversity of unexplored habitats, and characterized using a polyphasic approach. The isolate showed chemotaxonomic and morphological features consistent with members of the genus Nonomuraea. The 16S rRNA gene sequence analysis revealed that strain M3C6T shared the highest similarity, at 98.7% sequence identity, to Nonomuraea basaltis 160415T and Nonomuraea turkmeniaca DSM 43926T. However, the ANI and dDDH values between strain M3C6T and these reference strains were fairly low, ranging from 84.0 to 84.6% and 31.8 to 33.7%, respectively, below the generally accepted cutoffs for ANI and DDH that delineate different prokaryotic species. Genomic analysis of strain M3C6T showed that it had a genome size of 10.38 Mbp and a DNA G+C content of 69.5 mol%. Based on these chemotaxonomic, phenotypic, and genomic data, strain M3C6T is classified as a novel species within the genus Nonomuraea, for which the name Nonomuraea marmarensis sp. nov. is proposed. The type strain is M3C6T (= KCTC 49983T = CGMCC 4.8035T). Genomic analyses confirmed the high potential of M3C6T to produce specialized secondary metabolites.