Fikrettin Şahin

Antimicrobial activity of aqueous and methanol extracts of Juniperus oxycedrus L.

Aqueous and methanol extracts of the leaves of Juniperus oxycedrus were investigated for their in vitro antimicrobial properties. The plant was collected from Pelitli Village of Gebze, Kocaeli, in the Marmara region of Turkey. Juniperus oxycedrus is widely used as traditional folk medicine in Turkey for treatment of different infectious diseases. The antimicrobial activity of the extracts against 143 laboratory strains belonging to 56 bacterial species, and 31 isolates of 5 fungi species were evaluated based on the inhibition zone using the disc-diffusion assay, minimal inhibition concentration (MIC) and minimal bactericidal concentration (MBC) values. The aqueous extract of J. oxycedrus had no antimicrobial effect against the test microorganisms whereas the methanol extract had inhibitory effects on the growth of 57 strains of 24 bacterial species in the genera of Acinetobacter, Bacillus, Brevundimonas, Brucella, Enterobacter, Escherichia, Micrococcus, Pseudomonas, Staphylococcus, and Xanthomonas. In addition 11 Candida albicans isolates at a concentration of 31.25-250 micro g/ml were also inhibited.

Synthesis, characterisation and biological activity of novel 4-thiazolidinones, 1,3,4-oxadiazoles and some related compounds

Two novel series of 4-thiazolidinone derivatives, namely 2-substituted-3-([4-(4-methoxybenzoylamino)benzoyl]amino)-4-thiazolidinones (7a-e) and 2-[4-(4-methoxybenzoylamino)benzoylhydrazono]-3-alkyl-4-thiazolidinones (5a-c) together with 2-[4-(4-methoxybenzoylamino)phenyl]-5-(substituted phenyl)amino-1,3,4-oxadiazoles (6a-c) have been synthesised as title compounds. N(1)-[4-(4-methoxybenzoylamino)benzoyl]-N(2)-substituted methylene hydrazines (3a-e) and 1-[4-(4-methoxybenzoylamino)benzoyl]-4-substituted phenyl thiosemicarbazides (4a-f) were also prepared and used as intermediate to give the title compounds. All synthesised compounds were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv and antimicrobial activities against various bacteria and fungi. Compounds 7a and 7b were found as the most active derivatives demonstrating 90 and 98% inhibition of mycobacterial growth of M. tuberculosis H37Rv in the primary screen at 6.25 microg mL(-1), respectively. However, level II assay revealed that the MIC values were not less than 6.25 microg mL(-1). None of the compounds showed significant antimicrobial activity against the microorganisms used whereas 3a and 7a inhibited the growth of several bacteria and fungi.

Evaluation of antimicrobial activities of Satureja hortensis L.

The present study was designated to evaluate the antimicrobial activities of methonol and hexane extracts of Satureja hortensis L. which is an annual herb used as traditional folk medicine in Eastern Anatolia region of Turkey for the treatment of different infectious diseases and disorders. The antimicrobial activities of the extracts against 147 laboratory strains belong to 55 bacterial species, and 31 isolates of 1 yeast and 4 fungi species were tested by using disc diffusion assay. The results showed that hexane extract of Satureja hortensis had no antifungal, but antibacterial activity against four strains of three Bacillus species whereas methanol extract of Satureja hortensis had both anticandidal and antibacterial effects. It inhibited the growth of 23 strains of 11 bacterial species and 6 isolates of Candida albicans, at the concentration of 300microg/ml. Satureja hortensis did not show antimicrobial activity against the remaining microorganisms (83%) tested including most and all of the clinic and plant pathogenic microorganisms, respectively. Methanol extract showed stronger and broader spectrum of antimicrobial activity as compared to hexane extract.

Sugar beet and barley yields in relation to inoculation with N2-fixing and phosphate solubilizing bacteria

Recently, there has been a resurgence of interest in bioorganic fertilizers as part of sustainable agricultural practices to alleviate drawbacks of intensive farming practices. N2-fixing and P-solubilizing bacteria are important in plant nutrition increasing N and P uptake by the plants, and playing a significant role as plant growth-promoting rhizobacteria in the biofertilization of crops. A study was conducted in order to investigate the effects of two N2-fixing (OSU-140 and OSU-142) and a strain of P-solubilizing bacteria (M-13) in single, dual and three strains combinations on sugar beet and barley yields under field conditions in 2001 and 2002. The treatments included: (1) Control (no inoculation and fertilizer), (2) Bacillus OSU-140, (3) Bacillus OSU-142, (4) Bacillus M-13, (5) OSU-140 + OSU-142, (6) OSU-140 + M-13, (7) OSU-142 + M-13, (8) OSU-140 + OSU-142 + M-13, (9) N, (10) NP. N and NP plots were fertilized with 120 kg N ha−1 and 120 kg N ha−1 + 90 kg P ha- for sugar beet and 80 kg N ha−1 and 80 kg N ha−1 + 60 kg P ha−1 for barley. The experiments were conducted in a randomized block design with five replicates. All inoculations and fertilizer applications significantly increased leaf, root and sugar yield of sugar beet and grain and biomass yields of barley over the control. Single inoculations with N2-fixing bacteria increased sugar beet root and barley yields by 5.6–11.0% depending on the species while P-solubilizing bacteria alone gave yield increases by 5.5–7.5% compared to control. Dual inoculation and mixture of three bacteria gave increases by 7.7–12.7% over control as compared with 20.7–25.9% yield increases by NP application. Mixture of all three strains, dual inoculation of N2-fixing OSU-142 and P-solubilizing M-13, and/or dual inoculation N2-fixing bacteria significantly increased root and sugar yields of sugar beet, compared with single inoculations with OSU-140 or M-13. Dual inoculation of N2-fixing Bacillus OSU-140 and OSU-142, and/or mixed inoculations with three bacteria significantly increased grain yield of barley compared with single inoculations of OSU-142 and M-13. In contrast with other combinations, dual inoculation of N2-fixing OSU-140 and P-solubilizing M-13 did not always significantly increase leaf, root and sugar yield of sugar beet, grain and biomass yield of barley compared to single applications both with N2-fixing bacteria. The beneficial effects of the bacteria on plant growth varied significantly depending on environmental conditions, bacterial strains, and plant and soil conditions.

Effect of plant growth-promoting bacteria and soil compaction on barley seedling growth, nutrient uptake, soil properties and rhizosphere microflora

Inoculants are of great importance in sustainable and/or organic agriculture. In the present study, plant growth of barley (Hordeum vulgare) has been studied in sterile soil inoculated with four plant growth-promoting bacteria and mineral fertilizers at three different soil bulk densities and in three harvests of plants. Three bacterial species were isolated from the rhizosphere of barley and wheat. These bacteria fixed N2, dissolved P and significantly increased growth of barley seedlings. Available phosphate in soil was significantly increased by seed inoculation of Bacillus M-13 and Bacillus RC01. Total culturable bacteria, fungi and P-solubilizing bacteria count increased with time. Data suggest that seed inoculation of barley with Bacillus RC01, Bacillus RC02, Bacillus RC03 and Bacillus M-13 increased root weight by 16.7, 12.5, 8.9 and 12.5% as compared to the control (without bacteria inoculation and mineral fertilizers) and shoot weight by 34.7, 34.7, 28.6 and 32.7%, respectively. Bacterial inoculation gave increases of 20.3–25.7% over the control as compared with 18.9 and 35.1% total biomass weight increases by P and NP application. The concentration of N and P in soil was decreased by increasing soil compaction. In contrast to macronutrients, the concentration of Fe, Cu and Mn was lower in plants grown in the loosest soil. Soil compaction induced a limitation in root and shoot growth that was reflected by a decrease in the microbial population and activity. Our results show that bacterial population was stimulated by the decrease in soil bulk density. The results suggest that the N2-fixing and P-solubilizing bacterial strains tested have a potential on plant growth activity of barley.

Effects of Some Plant Growth Promoting Rhizobacteria (PGPR) on Graft Union of Grapevine

ABSTRACT In this study, effects of topical applications of three plant growth promoting rhizobacteria (PGPR) strains (Pseudomonas BA8, Bacillus BA16 and Bacillus OSU142) on graft union were evaluated in terms of success rate, callusing rate, callusing degree and full callusing rate on four different rootstock-scion combinations including 41B-Beyaz Çavuş, 41B-Italia, 5BB-Beyaz Çavuş and 5BB-Italia. The results showed that in general all of the bacterial strains had significant effects on all parameters tested in all rootstock-scion combinations compared with the control. Application of Pseudomonas BA8 in 41B-Beyaz Çavuş, Bacillus OSU142 in 41B-Italia, Pseudomonas BA8 in 5BB-Beyaz Çavuş, and Bacillus BA16 and Bacillus OSU142 in 5BB-Italia combination increased the success rate (83.3%, 93.3%, 80.0% and 86.7%, respectively) compared with the control (23.3%, 80.0%, 60.0% and 70.0%, respectively). Application of PGPR also increased the callusing rate, callusing degree and full callusing rate in all rootstock-scion combinations compared with control. Among the bacteria strains tested, Pseudomonas BA8 was the most effective PGPR strain which can be used for graft union of grapevine grown in commercial, sustainable or organic agriculture.

Identification of Resistance to Common Bacterial Blight Disease on Bean Genotypes Grown in Turkey

Common bacterial blight (CBB) in edible beans (Phaseolus vulgaris), incited Xanthomonas campestris pv. phaseoli, reduces bean yields and seed quality. The main objective of this study was to determine resistance to common bacterial blight in bean genotypes. Twenty-two bean genotypes grown in Turkey including common and snap bean cultivars/lines were collected from different parts of Turkey and tested for resistance against to Xanthomonas campestris pv. phaseoli strain MFD-11. All the common and snap bean lines/cultivars tested were moderately susceptible, susceptible or highly susceptible, except AG-7117 which was found resistant to Xanthomonas campestris pv. phaseoli. This is the first report of a resistance source in a common bean line (AG-7117) against Xanthomonas campestris pv. phaseoli.

Erwinia amylovora Strainlerinin Streptomisin Sülfata Karşı Duyarlılıkları ve Strainlerin Yağ Asidi Metil Esterleri ile Antibiyotiğe Duyarlılıkları Arasındaki İlişkinin Belirlenmesi / Determination of Relationship between Streptomycin Sulphate Susceptibili

OZET: Bu calismada; Erzurum, Erzincan, Artvin, Kars ve Igdir illerinde yumusak cekirdekli meyve agaclarindan izole edilen ates yanikligi hastaliginin etmeni Erwinia amylovora’nin toplam 41 straininin streptomisin sulfata karsi duyarliliklari test edilmis; mikrobial tani sistemi (MIS) ile strainlerin yag asidi metil ester (FAME) gruplari belirlenerek, patojenin yag asitleri ve antibiyotiklere duyarliliklari arasindaki iliski arastirilmistir. Elde edilen sonuclara gore strainlerin % 31,7’sinde dayaniklilik tespit edilmistir. Yag asidi metil esterleri bakimindan patojenin 4 farkli grubunun oldugu belirlenmistir. Gruplar arasindaki farkliligin ise % 8 ile % 24 arasinda degistigi gorulmustur. Ayrica dayaniklilik oraninin 2. grupta en yuksek duzeyde (% 83.3) oldugu tespit edilmistir. Bu oran 1. grup icin % 27.6 bulunurken 3. ve 4. grupta dayanikli straine rastlanmistir. Ikinci grubun farki; 18:1 w7c yag asidinin diger gruplara gore cok yuksek duzeyde olmasi (% 30.96-43.8) ve diger gruplarin hic birisinde bulunmayan 16:0 3OH (% 3.27-4.14) ve 16:1 2OH (% 1.08-2.18) yag asitlerinin bu grupta bulunmasidir. Sonuc olarak; Dogu Anadolu Bolgesi’nde Erwinia amylovora’nin streptomisin sulfata karsi dayanikli strainlerinin gelistigi ilk olarak bu calismada tespit edilmistir. Ilave olarak, bu bakterinin FAME gruplari ile streptomisin sulfata karsi dayanikliligi arasinda bir iliskinin olmasindan dolayi; bakterilerin FAME profillerinin laboratuar sartlarinda antibiyotik duyarliliklarinin belirlenmesinde yeni bir yontem olarak kullanilabilecegi dusunulmektedir. Anahtar Kelimeler: Erwinia amylovora, FAME, MIS, streptomisin sulfat, yag asidi Kars and Igdir province, were tested for susceptibilities to streptomycin sulphate. In addition; it was determined to fatty acid methyl esters (FAME) group of the strains, and investigated of relationship between streptomycin susceptibility of them and their FAME group. According to these results, resistance to streptomycin of tested strains was 31.7%. It was determined four different FAMEs groups of strains by using microbial identification system (MIS) system. The difference between groups was changed from 8% to 24%. The highest rate of resistance was in second group (83.3%) and first group (27.6%), and there was not any resistance strains in other groups.. Different of second group from others was that 18:1 w7c fatty acid was the highest level (30.96-43.8%), and there was 16:0 3OH (30.96-43.8%) and 16:1 2OH (1.08-2.18%) fatty acids in only this group. Consequently, this is the first report demonstrating resistance of strains Erwinia amylovora to streptomycin sulphate in Eastern Anatolia Region. In addition, because of the fact that there is a relationship between resistance of bacterial strains to streptomycin sulphate and their FAME profiles, we think that FAME profiles of this bacterium can be used as a new method for determination of bacterial antibiotic resistance in laboratory conditions. Keywords: Erwinia amylovora, FAME, fatty acid, MIS, streptomycin sulphate