Purification and characterization of Stenotrophomonas maltophilia chitinase with antifungal and insecticidal properties.

This study aimed to determine the ability of bacteria to produce the chitinase enzyme, purify, and characterize the enzyme from the isolate with the best activity, and determine the use of this purified enzyme as a biocontrol agent. The chitinolytic bacterium was identified as Stenotrophomonas maltophilia. The chitinase enzyme was purified 1.4 times at a 30% ammonium sulfate concentration with a yield of 40.7%. Following partial purification, the enzyme was purified by ion-exchange chromatography using HiPrep Q XL 16/10 column and HiPrep™ 26/10 desalting column with 25.34% and 18.12% yields, respectively. It was calculated that the purified enzyme had a molecular weight of 52 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum activity of the enzyme was determined at 50 °C and pH 7.0. Enzyme activity was most induced by Fe2+, while it was most inhibited by Zn2+ at 5 mM concentration. Km and Vmax values of the enzyme for colloidal chitin were calculated as 1.6419 mg/mL and 16.129 U/mg, respectively. The purified chitinase was used as a biocontrol agent against the fungus Fusarium oxysporum and potato beetle Leptinotarsa decemlineata. The enzyme was shown to be effective in reducing the growth of fungus and causing disruption of the chitin structure of potato beetle.

Substituted phenethylamine-based ß-lactam derivatives: Antimicrobial, anticancer, and ß-lactamase inhibitory properties.

In this study, a series of novel ß-lactam derivatives were synthesized with yields ranging from 41 % to 91 %, and their antimicrobial activities were investigated against bacterial and fungal isolates that cause nosocomial infections. The results revealed that the novel ß-lactam derivatives, especially compound 19, showed antibacterial activities ranging from 0.98 to 250 µg/mL. In contrast, the compounds showed no antifungal activity against fungal isolates. Following that, biochemical (Nitrocefin) investigation of compounds with antibacterial activity was carried out, as well as their effects on the ß-lactamase enzyme. According to the results, the compounds inhibited the ß-lactamase enzyme against bacterial isolates. Furthermore, the anticancer activity and toxicity profiles of ß-lactam derivatives were also studied against colorectal cancer (Caco-2), the most common type of cancer, and non-human dermal fibroblast cell line. The results revealed that compound 19 was shown the best anticancer activity and lowest toxicity profile among other compounds. Therefore, these compounds, especially compound 19, could be useful in the treatment of colorectal cancer and related nosocomial infections. Furthermore, the potential of being an antibiotic can be put forward by investigating the resistant mechanism and further pharmacological studies.

Identification, characterization and hydrolase producing performance of thermophilic bacteria: geothermal hot springs in the Eastern and Southeastern Anatolia Regions of Turkey.

In the last two decades, researchers have increasingly focused on the rich microorganism-based diversity of natural hot spring sources to explore the benefits of thermophiles in industrial and biotechnological fields. Within the scope of this study, a total of 83 thermophilic Bacilli strains were isolated from 7 different geothermal hot springs (at temperatures ranging between 40 and 85 °C) located in the Eastern and Southeastern Anatolia Regions of Turkey. The physiological, morphological, biochemical and molecular properties of the isolates were determined. As a result of the 16S rRNA gene sequence analysis, 5 different species (Bacillus licheniformis, Bacillus sp., Bacillus subtilis, Geobacillus kaustophilus, and Weizmannia coagulans,) were identified. B. licheniformis and B. subtilis were the most frequently encountered species among those obtained from the researched hot spring sources. Phylogenetic analysis was conducted to evaluate the phylogenetic relationships of the isolated species. The results showed that there was no significant difference between the groups and the bacteria in terms of the locations or optimum temperatures of the isolates. The bacterial isolates were screened for amylase, cellulase, lipase and protease hydrolytic enzyme activities. The hydrolytic enzyme production potentials among the isolates were identified in 68 (82%) isolates for amylase, 34 (41%) for cellulase, 69 (83%) for lipase and 73 (88%) for protease. All isolates were found to have at least one or more extracellular enzyme activities. Additionally, it was determined that 27 of the existing isolates (32.8%) were able to produce all of the aforementioned hydrolytic enzymes.

Carbonate and silicate dissolving bacteria isolated from home-made yogurt samples.

In the current study, twenty-eight bacterial strains were isolated from home-made yogurt samples from Agri Province, Turkey. The bacterial strains were identified by conventional and molecular techniques. Among the twenty- eight isolates, seventeen isolates were identified according to the 16 S rDNA region and determined to belong to five different genus including Sphingomonas (8 isolates), Burkholderia (5 isolates), Lactobacillus (2 isolates), Lactococcus (1 isolate), Staphylococcus (1 isolate). In this study, the presence of Burkholderia in home-made yogurt samples were reported for the first time, whereas Sphingomonas was detected for the second time. We also investigated the carbonate (CaCO3 and MgCO3) and silicate ( CaSiO3 and MgSiO3) dissolving potential of seventeen bacterial isolates. Among these seventeen bacterial isolates, fifteen bacterial isolates have CaCO3-dissolving and 10 bacterial isolates have MgCO3-dissolving potential. The silicates dissolution ability was relatively less than that of carbonates dissolving. We observed that six bacterial isolates have CaSiO3 and only two bacterial isolates have MgSiO3 dissolution abilities. In conclusion, this work clearly shows the diversity of bacteria existing in fermented cow milk samples in Agri Province, Turkey, which could be considered as valuable sources for lactic acid bacteria (LAB) isolation and further probiotic potential.

Composition and bioactivity of essential oil from Stachys macrostachya (Wend.) Briq.

Stachys species belonging to Lamiaceae family have been used for medicinal purposes since ancient times. The aim of the present study was to investigate the chemical compositions and antibacterial, anti-tyrosinase activities of the essential oil of Stachys macrostachya. The essential oil was prepared by hydrodistillation method using a Clevenger-type apparatus and chemical composition was determined by gas chromatography (GC). The antibacterial activity of essential oil was performed by the disc diffusion and microdilution broth method against five Gram-positive and two Gram-negative bacteria. The tyrosinase inhibitory activity was evaluated by minor modifications of Masuda's method. According to the results of GC analyses, twenty-three compounds were identified representing 91.9% of the total volatile composition. The main compounds were germacrene D (12.2%), globulol (10.9%), α-pinene (9.7%), and valencene (7.6%). The present study showed that the tested essential oil of S. macrostachya exhibited antibacterial activity against Acinetobacter baumannii (MIC 62.50 µg/mL) and tyrosinase inhibition activity (IC50 22.86 ± 0.82 µg/mL). These results suggest that the essential oil could be exploited as a potential source of natural antimicrobial agents of this bacterium as well as tyrosinase inhibitors.

Characterization and biotechnological application of protease from thermophilic Thermomonas haemolytica.

In this study, it was aimed to determine the ability to produce protease enzyme of Thermomonas haemolytica isolated from geothermal Nenehatun hot spring in Turkey and utilization of this enzyme in the detergent industry to remove protein stains. The protease-producing strains were screened from hot springs, and a potential strain was identified as T. haemolytica according to morphological, physiological and biochemical characteristics and sequence of 16S rRNA gene. Maximum protease activity was observed at 55 °C and pH 9.0 at 72 h of incubation. Activity was very stable between 50 and 65 °C and pH 8.0-10.0, respectively. The enzyme activity was significantly inhibited by PMSF and partly inhibited by EDTA, EGTA, SDS, and urea. Some divalent metal ions such as Ca2+, Mg2+, and Mn2+ increased the enzyme activity, while Zn2+ and Cu2+ decreased. Michaelis-Menten constant (Km) and maximum velocity (Vmax) values were calculated by Lineweaver-Burk plot as 125 EU/ml and 1262 mg/ml, respectively. The biochemical characterization of the protease obtained from T. haemolytica was performed and applied on the blood and grass-stained fabrics with detergent to evaluate the stain removal performance of the enzyme. It was observed that the application of detergent with enzyme was more effective than the detergent without enzyme to clean up the stained fabrics. This is the first report of characterization of the protease of T. haemolytica. According to results obtained from this study, this new strain is a promising candidate for industrial applications in production of detergent.

Identification and Characterization of Novel Thermophilic Bacteria from Hot Springs, Erzurum, Turkey.

The aim of present study was the isolation and characterization of thermophilic bacteria from three different hot springs in Erzurum, Turkey. For this purpose, 85 bacteria were isolated and characterized by ERIC-PCR genomic fingerprinting and classical identification methods such as morphological, physiological and biochemical characteristics. According to the results, 29 bacterial isolates with different band profiles were analyzed by 16S rRNA gene sequencing and identified as belonging to the genus of Bacillus, Pseudomonas, Silanimonas, Thermomonas and Thauera. This is the first report on the isolation of Silanimonas lenta, Thauera sp. and Thermomonas haemolytica from Turkey Hot Springs. The amylase, lipase and protease enzyme production potentials of the isolates were 80%, 91.25% and 81.25%, respectively. Moreover, 56.47% of the isolates (48) were able to produce all of these enzymes. Therefore, the results of the study indicated that these bacteria and their enzymes can be used as a source of industrial enzymes.

Chemical Composition and Antibacterial Activity of Essential Oils of Two Species of Lamiaceae against Phytopathogenic Bacteria.

In this study, we aimed to determine chemical composition and antibacterial activities of Satureja hortensis and Calamintha nepeta against to 20 phytopathogenic bacteria causing serious crop loss. The essential oils of S. hortensis and C. nepeta were isolated by the hydrodistillation method and the chemical composition of the essential oils were analyzed by GC-MS. The antibacterial properties of the essential oils were evaluated against 20 phytopathogenic bacteria through Disc diffusion assay and micro dilution assay. The results revealed that the essential oils of S. hortensis and C. nepeta have significant antibacterial activity. Furthermore, the findings of the study are valuable for future investigations focusing on the alternative natural compounds to control plant diseases.

The effect of novel ß-lactam derivatives synthesized from substituted phenethylamines on resistance genes of MRSA isolates.

This study focuses on the activity of previously reported imine and ß-lactam derivatives against methicillin-resistant Staphylococcus aureus (MRSA) isolates. The presence of mecA and blaZ genes in the isolates was determined, and the minimum inhibitory concentration (MIC) values were determined based on the antibacterial activity against these isolates. Active compounds were selected and their ability to act against resistant isolates in vitro was determined. Concurrently, biochemical (nitrocefin) and molecular (qRT-PCR) tests were used to investigate the ability of the compounds to induce resistance genes in MRSA isolates. The cytotoxicity of the compounds on human dermal fibroblasts (HDF) was investigated. The MIC values of compounds (10) and (12) against MSSA and MRSA isolates were 7.81 and 15.62 µg ml-1, respectively. The most active compounds were identified as (10) and (12), and it was observed that the isolates did not develop resistance to these compounds in vitro. These compounds were found to inhibit ß-lactamase, reduce the expression of resistance genes, and exhibit reduced HDF cell toxicity in a dose-dependent manner. According to the findings of the study, it can be concluded that these compounds show promise as hits with an interesting mechanism of action for further chemical modifications to develop new MRSA inhibitors.

Green alternatives to petroleum-based plastics: production of bioplastic from Pseudomonas neustonica strain NGB15 using waste carbon source.

Polyhydroxyalkanoates have attracted great interest as a suitable alternative to petrochemical based plastics due to their outstanding properties such as biodegradability and biocompatibility. However, the biggest problem in the production of microbial polyhydroxyalkanoates is low cost-effectiveness. In this study, polyhydroxyalkanoate production was carried out using waste substrates with local isolates. Culture conditions were optimized to increase the polyhydroxyalkanoate production potential. The produced polyhydroxyalkanoate was characterized by FTIR analyses, and its metabolic pathway was determined by real-time PCR. According to the results, the best polyhydroxyalkanoate producer bacteria was characterized as Pseudomonas neustonica NGB15. The optimal culture conditions were detected as 30 g/L banana peel powder, 25 °C temperature, pH 8, and 4-day incubation time. Under the optimized conditions, 3.34 g/L PHA production was achieved. As a result of FTIR analyses, major peaks were obtained at 1723, 1277, 1261, 1097, 1054, and 993 cm-1. These peaks represent that the type of produced polyhydroxyalkanoate was poly-ß-hydroxybutyrate. According to gene expression profile of NGB15, it was determined that Pseudomonas neustonica NGB15 produces PHA using the de novo fatty acid synthesis metabolic pathway. In conclusion, poly-ß-hydroxybutyrate production by Pseudomonas neustonica NGB15 using a low-cost fermentation medium has been shown to be biotechnologically promising.

Immunopathological investigation of a gerbil model of cutaneous leishmaniasis.

Leishmaniasis, caused by Leishmania species (intracellular protozoans), is a chronic, systemic disease that causes skin (cutaneous) and internal organ infections (visceral). Its prevalence has increased in recent years. Leishmania species are considered important pathogens that affect public health. After infecting an individual, the pathogen disrupts the immune system, but, there are not enough studies on which immune mechanisms are affected. The aim of this study was to establish a Leishmania major infection model (the causative agent of cutaneous leishmaniasis) in gerbils (Meriones unguiculatus) and to investigate the immune response in this model by examining the expression of important inflammatory genes (IL-1ß, IL-2, IL-6, IFN-É£ and TNF-α). The presence of parasites was confirmed by microscopic examination of samples taken from the lesions and culture studies. The expression of inflammatory cytokine genes was significantly increased in infected gerbils. The changes indicated that both the Th1 and Th2 pathways are activated in cutaneous leishmaniasis infection. Hence, different immunopathological mechanisms should be evaluated in the pathogenesis of the disease.

Isolation and characterization of metal resistant-tolerant rhizosphere bacteria from the serpentine soils in Turkey.

Despite the number of studies describing metal hyper-accumulating plants and their associated bacteria in various regions and countries, there is no information on rhizosphere microbial potential of the Turkish serpentine soils. This study aimed to explore the rhizosphere microbial diversity of Ni-resistant, hyper-accumulating plants grown on Ni-rich soils and their metal tolerance-resistance characteristics. One hundred ninety-one locations were visited to collect soil and plant samples from different serpentine regions of Western Turkey. Following bioavailable and total Ni analysis of collected samples, the seeds of the selected plants with higher Ni content were taken to the growth/germination test in a range of serpentine soils in a growth chamber condition. In order to investigate the rhizosphere microbial diversity, Isatis pinnatiloba and Alyssum dasycarpum which were able to germinate and grow well in the preliminary tests, were introduced to 6-month greenhouse experiment in the range of three serpentine soils with higher bioavailable Ni content. I. pinnatiloba had a better stimulatory effect on the rhizosphere microbial diversity. A total of 22 bacterial isolates were identified from different soil conditions in the end of experiment. Following microbial identification and confirmation tests, 11 isolates were found to be resistant and tolerant to the increasing concentrations of Ni, Pb, Cd and Zn in the range of 50-2,000 mg L( - 1), which was considerably higher than those indicated by earlier studies. The strains isolated and identified from the Turkish serpentine soils were the members of genera Arthrobacter, Bacillus, Microbacterium and Staphylococcus.