Nazime Mercan

Effect of carbon and nitrogen sources and incubation times on poly-beta-hydroxybutyrate (PHB) synthesis by Bacillus subtilis 25 and Bacillus megaterium 12

In this study, poly-beta-hydroxybutyrate (PHB) production by the Bacillus subtilis 25 and Bacillus megaterium 12 strains was investigated in nutrient broth medium at different incubation times (between 6 h and 48h). The best PHB production and all yields of these strains were determined. The productions were 0.101 g/L, 0.142 g/L and the percentage yields were 18.03%, 14.79% after 45h, respectively. At 48th h, there was a decrease in PHB yields. In our study, the effects of different carbon and nitrogen sources on PHB production in these strains were also tested. While the strains produced less PHB in nutrient broth medium with different carbon and nitrogen sources, the highest level of PHB accumulation of the strains was observed in the medium with protease peptone. In this nutrient broth medium with protease peptone the percentage PHB yield of B. subtilis 25 was determined as 78.69%, while in the same nitrogen sources this percentage in B. megaterium 12 was determined to be 77.00%.

Production of poly-β-hydroxybutyrate (PHB) and differentiation of putative Bacillus mutant strains by SDS-PAGE of total cell protein

In this study, the putative mutant strains of Bacillus megaterium Y6, B. subtilis K8, B. sphaericus X3 and B. firmus G2 were studied for their poly--hydroxybutyrate (PHB) production capacities. Mutations were induced by using UV light, acriflavin and 5-bromourasil. Total cell proteins were extracted from 59 strains and compared using SDS-PAGE. For each strain, percentage yield of PHB according to cell dry weight was determined in a range of 1.46-63.45%. PHB production of 8 mutant strains were found to increase in comparison with parental strains. However, no increase in PHB production of mutant strains of B. sphaericus X3 was found. It was also determined that the protein profiles of the mutant strains with high PHB yield generally differed from the protein profiles of parental strains.

Antimicrobial activity and pollen composition of honey samples collected from different provinces in Turkey

The antibacterial activity of honey samples from different sources were collected and investigated against Bacillus cereus, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 27736, Morganella morganii, Micrococcus luteus NRRL B-4375, Escherichia coli ATCC 35218, and Candida albicans. Pathogens exhibited different sensitivities towards the honey samples. The results showed that majority of the honey samples (75%) generally inhibitied the bacteria tested. The honey samples which were obtained from İzmir (samples 1 and 2) proved more effective as inhibitors against P. aeruginosa, E. coli, and S. aureus. The honey which was obtained from Muğla (sample 5) exhibited high anticandidal activity on C. albicans. A comparison of the honey samples on the basis of pollen content revealed that they were heterofloral, and samples which had highest antibacterial activity against P. aeruginosa, E. coli, and S. aureus were dominated by pollen from Chenopodiaceae/Amaranthaceae (sample 1), and Trifolium, Trigonella, Cyperaceae, Zea mays and Anthemis taxa (sample 2). The honey proved more effective on bacteria than antibiotics.

Antioxidant and antimicrobial properties of ethanolic extract fromLepista nuda (Bull.) Cooke

Antioxidant capacity and antimicrobial activities ofLepista nuda (Bull.) Cooke extracts obtained with ethanol were investigated. Four complementary test systems, namely DPPH free radical scavenging, β-carotene/linoleic acid systems, total phenolic compounds and total flavonoid concentration, have been used. Linoleic, acid inhibition values ofL. nuda ethanolic extract, BHA and α-to copherol standards were found to be 84.3% 98.9% and 99.2% respectively in the concentration of 160μg/ml. Total flavonoid amount was 8.21 ± 0.56 μg mg−1 quercetin equivalent while the phenolic compound amount was 48.01 ± 0.29 μg mg−1 pyrocatechol equivalent in the extract. The antimicrobial activity ofL. nuda extract was testedin vitro by using the agar-well diffusion method. TheL. nuda extract showed antibacterial activity againstMicrococcus flavus, Micrococcus luteus, Bacillus cereus, Yersinia enterocolitica, Staphylococcus aureus, Salmonella enteritidis andEscherichia coli. TheL. nuda extract did not exhibit antican didal activity againstCandida albicans. The extracts could be suitable as antimicrobial and antioxidativeagents in the food industry.

Screening of the constituents, antimicrobial and antioxidant activity of endemic Origanum hypericifolium O. Schwartz & P.H. Davis

The chemical compositions, total phenol content, antioxidant and antimicrobial activities with oxidant status of the essential oil from an endemic Turkish species, Origanum hypericifolium, were investigated. Steam distillation (SD) was used to isolate the essential oils, and the chemical analyses were performed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity was tested by agar disc diffusion method against Morganella morganii (clinic isolate) , Micrococcus flavus (clinic isolate) , Micrococcus luteus NRLL B-4375, Proteus vulgaris RSKK 96026, Escherichia coli ATCC 11230, Escherichia coli ATCC 25922, Yersinia enterecolitica RSKK 1501, Staphylococcus aureus ATCC 25923, S. aureus ATCC 25933, S. aureus ATCC 12598, S. aureus (clinic isolate), MRSA 1 (clinic isolate), MRSA 2 (clinic isolate), MRSA 3 (clinic isolate) and MRSA 4 (clinic isolate). The major compounds found in volatiles of O. hypericifolium were p-cymene, carvacrol and γ-terpinene. Results showed that O. hypericifolium has the potential for being used in food and medicine because of its antioxidant and antibacterial activity.

Chemical composition effects onto antimicrobial and antioxidant activities of propolis collected from different regions of Turkey

Chrysin, apigenin, flavonoids, flavanones, naringenin, ethyl oleate, 3-4-dimethoxy-cinnamic acid and 9-octadecenoic acid were the predominant components of propolis samples collected from different regions of Turkey. The extracts of P3 from Denizli-Başkarci, P5 from Denizli and P7 from Tekirdaĝ had effective antibacterial activities on Gram-negatives. Chrysin, which has antibacterial activity, was found to be high concentration. The extracts of P3, P2B from Aydin and P6 from Konya had much more effective antibacterial activities on Gram-positives. The total antioxidant activity increased with the increasing amount of extracts added to linoleic acid emulsion. All doses of propolis ethanol extract displayed antioxidant activity.

CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OIL FROM Nepeta cadmea

The Genus Nepeta L. (Lamiaceae) is represented by 34 species in Turkey, including eighteen endemic species [1, 2]. Nepeta cadmea Boiss. is an endemic species with limited distribution and included in the lower risk and least concern category in the red data book of Turkey [3]. Here we report on the antimicrobial activity of the essential oils from N. cadmea because very little information is available on this endemic species. Table 1 shows the percentages of the main components present in the essential oils isolated from N. cadmea collected in June from Honaz Mountain. The yields of essential oil from N. cadmea on a dry weight basis was 2.1% (v/w). Thirteen components in N. cadmea (97.91%) were identified. The components are listed in order of their elution time on the HP 1 MS column. Among the compounds, nepetalactone (81.6%), caryophyllene (3.71%), and germacrene D (3.25%) were identified as the major components in the essential oil of N. cadmea. The antimicrobial activity of the essential oil measured by the disc diffusion method is given in Table 2. The essential oil isolated from N. cadmea showed antimicrobial activity, but differences in microbial susceptibility were observed. Our findings indicate that the essential oil isolated from N. cadmea has antimicrobial activity and can be used to control microorganisms since this has been used in folk medicine for decades. It will be worth-while to investigate the individual components in antibacterial and antifungal assays.

Discrimination of Bacillus sphaericus strains by filtrate protein profiles

are compared both in vegetative and sporulated stages according to their filtrate protein profiles obtained by Native-PAGE and SDS-PAGE. When the strains are compared in the sporulated stage, filtrate protein profiles obtained by Native-PAGE differentiated the strains according to their phage and serogroups. On the other hand, the typing according to filtrate protein profiles is correlated with serotyping and phage typing. The discrimination of