Ömer Ertürk

Isolation of some pathogenic bacteria from the great spruce bark beetle, Dendroctonus micans and its specific predator, Rhizophagus grandis

Some bacteria were isolated from Dendroctonus micans and its specific predator, Rhizophagus grandis. Six bacteria from D. micans were identified as Bacillus pumilus, Enterobacter intermedius, Citrobacter freundii, Cellulomonas flavigena, Microbacterium liquefaciens and Enterobacter amnigenus, three bacteria from R. grandis as Klebsiella pneumoniae, Pantoea agglomerans and Serratia grimesii, on the basis of fatty acid methyl ester analysis and carbon utilization profile by using Microbial Identification and Biolog Microplate Systems. Their insecticidal effects were tested on larvae and adults of D. micans.

Effects of four Bacillus spp. of soil origin on the Colorado potato beetle Leptinotarsa decemlineata (Say)

Four species of Bacillus were isolated from soil in an effort to find safe, effective and alternative biological control agents against plant pests. These bacteria were identified as Bacillus pumilus, Bacillus sphaericus, Bacillus megaterium and Bacillus cereus on the basis of fatty acid methyl ester analysis and carbon utilization profiles by using Microbial Identification and Biolog Microplate Systems. Laboratory experiments carried out to determine the insecticidal activities of these isolates showed that B. pumilus caused 95.7 and 26.7% mortality and B. sphaericus caused 74.5 and 23.3% mortality of Leptinotarsa decemlineata larvae and adults, respectively. B. cereus and B. megaterium showed 51.1 and 29.7%, respectively, of L. decemlineata larvae. This study presents at least two Turkish isolates from the genus Bacillus showing high insecticidal activity against L. decemlineata.

The antimicrobial and antioxidant activities of extracts obtained from some moss species in Turkey

Summary Introduction: Pharmaceutical industry is forced to develop new pharmacologically active molecules. Like other plants, mosses are considered to be potential source of new biologically active compounds. Objective: The present study was designed to evaluate the antimicrobial and antioxidant activity of 8 moss species: Hypnum cupressiforme, Homalothecium sericeum, Thuidium delicatulum, Homalothecium lutescens, Homalothecium nitens, Leucodon sciuroides, Ctenidium molluscum, and Eurhynchium striatulum obtained from Turkey. Methods: The antimicrobial activity of extracts was investigated against four Gram (+) and six Gram (−) bacterial strains and three tested fungi. Total phenolic content (TPC), cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), and DPPH radical scavenging activity assays were applied to determine the antioxidant activity. Results: All moss extacts were found to be active against all the organisms except Homalothecium nitens. Especially, H. sericeum and E. striatulum showed the best antioxidant activity. Conclusion: The obtained results show that mosses may be used as possible natural antioxidant, antimicrobial agents to control various human, animal and plant diseases.

Distribution and occurrence of the insect pathogenic alga Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in the predator beetle Rhizophagus grandis G: yll. (Coleoptera: Rhizophagidae)-rearing laboratories.

The distribution and occurrence of the insect pathogenic algae Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in the predator beetle Rhizophagus grandis (Coleoptera: Rhizophagidae)-rearing laboratories were studied and reported here for the first time. The insect pathogenic alga Helicosporidium sp. infection was observed in all R. grandis-rearing laboratories. The infection rate reached more than 20% which is significant among the samples in some R. grandis-rearing laboratories. The infection rates of the examined beetles showed noticeable differences between localities and years. There was no significant difference in the infection levels of male and female beetles. These results showed that Helicosporidium sp. is one of the factors that decrease efficiency of the R. grandis-rearing laboratories.

First record of the insect pathogenic alga Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) infection in larvae and pupae of Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) from Turkey

The predator beetle Rhizophagus grandis Gyll. (Coleoptera, Rhizophaginae) is one of the most important biological control agents, mass-bred and used to suppress populations of an important pest: the great spruce bark beetle, Dendroctonus micans. The achlorophyllous alga Helicosporidium sp. was first discovered in the pest. Later it was also found in the predator, but only in the adults. In this study, the pathogenic alga Helicosporidium sp. was discovered in larvae and early pupae of R. grandis for the first time. The morphological characteristics of the pathogenic alga were revealed by light and electron microscopy. Infection rates of Helicosporidium sp. in the larvae and pupae of R. grandis were 23.5% and 6.25%, respectively.

Chemical components and biological activities of two freshwater green algae from Ordu, Turkey / Türkiye’nin Ordu ilinden iki tatlı su yeşil alglerinin kimyasal bileşenleri ve biyolojik aktiviteleri

Abstract Objective: Scientists are looking for new resources which have biological activities. The present study was planned to evaluate the antioxidant and antimicrobial activity of ethanol and acetone extracts, as well as the volatile compounds of two freshwater green algal species Spirogyra spp. and Zygnema stellinum (Vaucher) C. Agardh belonging to Zygnemaphyceae (Conjugatophyceae) obtained from Ordu University Campus wetlands. Methods: The extracts were tested in vitro for their antimicrobial effects using disc diffusion method. Total phenolic content and the antioxidative activity according to FRAP and DPPH methods of the extracts were also determined. The secondary metabolites from the investigated extracts were identified using GC-MS. Results: The extracts dramatically inhibited almost all tested microorganisms. The antimicrobial activity of the acetone extract of the Zygnema against C. albicans was found as more higher than positive control Nystatin. In accordance with antimicrobial activity, the highest total phenolic content was also determined in the presence of the acetone extract of the Zygnema. Furthermore the highest FRAP value and the lowest EC50 (mg/mL) value were calculated for the same extract. The main components of the all consisted of dimethyl and diethyl ester of 1,2-benzenedicarboxylic acid. However, the abundance of these metabolites in the extracts was not associated with antimicrobial or antioxidant activity. Biological activities of these algal species could be attributed to chemicals such as 1-Pentadecene and 1-Tetradecene which were present in smaller amounts. Conclusion: Investigated algal species can be evaluated to use in biotechnological applications such as food industry and medicine. Ozet Amac: Bilim adamları, biyolojik aktivitelere sahip yeni kaynak arayışı icindedirler. Bu calışma Ordu Universitesi Kampusu sulak alanlarından elde edilen Zygnemaphyceae (Conjugatophyceae) ailesine ait Spirogyra spp. ve Zygnema stellinum (Vaucher) C. Agardh turu tatlı su yeşil alglerinin etanol ve aseton ekstraktlarının antioksidan ve antimikrobiyal aktivitelerinin yanı sıra ucucu bileşenlerinin de değerlendirilmesi amacıyla planlanmıştır. Metod: Ekstraktların antimikrobiyal etkileri disk difuzyon metodu kullanılarak hucre dışında test edilmiştir. Ekstraktların toplam fenolik icerikleri ve FRAP ve DPPH yontemlerine gore antioksidatif aktiviteleri de belirlenmiştir. İncelenen ekstraktların ikincil metabolitleri GC-MS kullanılarak teşhis edilmiştir. Bulgular: Ekstraktlar tum test edilen mikroorganizmaları onemli olcude inhibe etmişlerdir. C. albicans uzerinde Zygnema turunun aseton ekstraktının antimikrobiyal aktivitesi pozitif kontrol Nystatinden daha yuksek bulunmuştur. Antimikrobiyal aktivite ile uyumlu olarak, en yuksek toplam fenolik icerik de Zygnema turunun aseton ekstraktı durumunda belirlenmiştir. Ayrıca, en yuksek FRAP değeri ve en duşuk EC50 (mg/mL) değeri de aynı ekstrakt icin hesaplanmıştır. Tum ekstraktların başlıca bileşenleri 1,2-benzendikarboksilik asidin dimetil ve dietil esterlerinden oluşmaktadır. Fakat bu metabolitlerin bolluğu antimikrobiyal veya antioksidan aktivite ile ilişkili değildir. Bu alg turlerinin biyolojik ativiteleri daha kucuk miktarlarda bulunan 1-pentadeken ve 1-tetradeken gibi kimyasallara atfedilebilir. Sonuc: İncelenen alg turleri gıda endustrisi ve ilac gibi biyoteknolojik uygulamalarda değerlendirilebilir.

Insecticidal effects of selected biological control agents on the larvae of Plutella xylostella (Lepidoptera: Plutellidae)

To identify a more effective and safe biological control agent against a common cabbage pest, Plutella xylostella (L.) (Lepidoptera: Plutellidae), the insecticidal effects of selected biological agents were evaluated. The highest insecticidal effects determined were 100, 73.5, 45.5, 47 and 55.3% using toxin HD‐1 (isolated from the Harry Dumagae strain of Bacillus thuringiensis), toxin BTS‐1 (isolated from the tenebrionis strain of B. thuringiensis), B. thuringiensis Berliner, B. thuringiensis israelensis and B. thuringiensis kurstaki, respectively.

Effect of Cadmium Application on Antimicrobial, Antioxidant and Total Phenolic Content of Basil Genotypes

Background: Exposure to heavy metals leads to increase in reactive oxygen species. Plants have many strategies to counteract the toxic effects of heavy metal stress by activating certain intermediary metabolic activities and making physiological adjustments. Objective: This study was designed to determine total phenolic contents and antimicrobial and antioxidant activities of eight Ocimum basilicum L. genotypes grown in a soil exposed to cadmium at different levels. Methods: Total phenolic contents were calculated as gallic acid equivalent. Antioxidant activity was studied based on DPPH free radical scavenging activity. Antimicrobial activity was determined by disc diffusion method against several microorganisms. Results: The highest antimicrobial activity was observed in the case of genotype 5 against Bacillus subtilus with the inhibition diameter value as 18.50 mm for basil grown at Cd free soil. This value just decreased to 17.57 mm at the conditions with 40 mg/kg Cd. Depending on increase at cadmium dose, the best grade increase in antimicrobial activity was also observed against B.subtilus for genotype 7. Total phenolic content and DPPH radical scavenging activity values were also increased with the Cd application at low doses. At very high doses of Cd a little decrease was observed for these values. Both of the phenolic content values and DPPH scavenging activities reached their maximum values for genotypes 1,7 and 8 grown at soil exposed to 20 mg/ kg Cd. Conclusion: Although cadmium is toxic, known beneficial properties of the basil samples have not deteriorated. These improved results are due to resistance of the basil plant to survive on adverse conditions.

Determination of some structural features of the nest paper materials of Dolichovespula Saxonica Fabricius, 1793 (Hymenoptera: Vespinae) in Turkey

The purpose of this paper is to identify the nest materials, some physical characteristics and the elemental composition of the nest of Dolichovespula saxonica (Fabricius, 1793). The nest surfaces were observed with a stereomicroscope and scanning electron microscope (SEM). In the inner surface of the D. saxonica nest the medium thickness of the fibers in the envelope and comb varied between 7.14 and 26.9 μm, respectively and averaged 16.4 μm. In the outer surface of the nest the medium thickness of the fibers in the envelope and comb were between 3.52 and 5.70 μm, respectively and averaged 4.63 μm. The nitrogen concentration of the nest of D. saxonica was 0.616% and the amount of protein was 3.08%. The percentages of the fibers, saliva, oil and the water absorption capacity were calculated as 67–70%, 23–30%, 12–18% and 110–140%, respectively. However, the amount of the element Cadmium (Cd) in the nest was found to have a value of 0.2 ppm. The major compounds of wasp nests are plant fibers, saliva and oil. However, the concentrations and ratios of the nest material compounds depend on the plant variety, place of origin, and time of harvest as well as on the processing and saliva conditions. The colors of the nest are beige, cream and grey with long dark brown lines. As a result of our study, we have found that the rates and quantities of physical characteristics, elemental composition and the fibers in the envelope and comb of the nest of D. saxonica change with environmental conditions.

Chrysomela ( Melasoma ) populi (Coleoptera: Chrysomelidae)’nin bakteriyel patojenlerinin araştırılması

In this study, bacterial pathogens in the populations of Chrysomela ( Melasoma ) populi (Coleoptera: Chrysomelidae) were investigated for the first time. Four bacterial species, two spore forming and two non-spore forming were isolated and identified using VITEK bacterial identification systems . These bacteria were identifiedas Bacillus vallismortis , Bacillus thuringiensis , Staphylococcus haemolyticus and Aerococcus viridans . All bacteria were isolated from this insect for the first time. Insecticidal potential experiments revealed that the isolated bacteria show mortalities on the adults of C. populi . Bacillus vallismortis , B. thuringiensis , S. haemolyticus and A. viridans have 65.9%, 70.6%, 50% and 53.3% mortalities on the C. populi adults, respectively.