Compositions and antimicrobial activities of the essential oils of two Hypericum species from Turkey

The chemical compositions of essential oils obtained from Hypericum hyssopifolium var. microcalycinum and Hypericum lysimachioides var. lysimachioides were analysed by using GC and GC-MS. Caryophyllene oxide was found to be the major component. The essential oils of both Hypericum species showed antimicrobial activity against nine microorganism at a concentration of 60 to 80 microg/ml.     

Determination of selected antibiotics in farmed fish species using LC‐MS/MS

The aim of the study was to monitor the occurrence of 37 antibiotics from different classes including fluoroquinolone, tetracycline, macrolide, sulphonamide, penicillin, amphenicol and cephalosporin in three different farmed fish species (n = 75; rainbow trout, see bass, gilthead see bream) from five cities in Turkey. A method for LC‐MS/MS was optimized and validated to assess these antibiotics. As a result, 25 samples showed contamination with at least one antibiotic residue. The most detected antibiotics were norfloxacin (NOR) (18.7%), marbofloxacin (MAR) (12%), tetracycline (TC) (10.7), danofloxacin (DAN) (9.3%), oxytetracycline (OTC) (9.3%), tilmicosin (TLM) (8%) and enrofloxacin (ENR) (6.7%). A total of 17.3% of samples examined were found to be contaminated with residues exceeding the maximum residue limits (MRLs). The results indicate that antibiotics are frequently used in aquaculture production without the lack of knowledge. This study also revealed that the consumption of farmed fish could produce a public health concern as the level of residues for some antibiotics was much higher than MRLs.     

Prediction of pine mistletoe infection using remote sensing imaging: A comparison of the artificial neural network model and logistic regression model

In this study, the prediction of pine mistletoe distribution in Scots pine ecosystems was explored using remote sensing variables to compare the multilayer perceptron (MLP) artificial neural network (ANN) and logistic regression (LR) model performances. For this purpose, 109 sample plots were distinguished in pure Scots pine forests (natural) in the Eastern Black Sea Region of Turkey. Distinguishing mistletoe-infected stands (69) and uninfected stands (40) was performed with field observations. The variables acquired from Landsat 8 (Level 1) images were used as independent variables for independent-sample t-test, MLP ANN and LR models. Remote sensing variables indicated that mistletoe-infected stands were in drier areas with a lower vegetation-leaf area index. Based on the performance results of both models, the sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV) and accuracy of the MLP ANN model were superior to those of the LR model. The prediction percentages (SEN, SPE, PPV and NPV) of mistletoe-infected stands were better than the prediction percentages of uninfected stands. The prediction accuracies of LR and MLP ANN models were 74.3% and 89.6%, respectively. However, all remote sensing variables were included in the prediction equation of the MLP ANN model, while the thermal infrared 1 (TIRS1) variable was included in the LR model. In the MLP ANN model, the TIRS1 variable also had the highest normalized importance (100%). The area under the curve (AUC) value for identifying the mistletoe-infected stands of Scots pine forests used by the MLP ANN model (0.892 ± 0.034) was higher than in the LR model (0.838 ± 0.039), explaining the more accurate predictions obtained from the MLP ANN model. The MLP ANN model showed much better performance than the LR model. The results of this study are expected to make important contributions to the identification of potential mistletoe-infected areas.     

Ground red peppers: capsaicinoids content,Scoville scores,and discrimination by an electronic nose

High-pressure liquid chromatography (HPLC) was used to determine the capsaicin, dihydrocapsaicin, and total capsaicinoids levels of different ground red pepper samples obtained from local retail markets in Izmir, Turkey. Scoville scores were determined using sensory tests. An electronic nose (EN) was used to discriminate ground red pepper samples by headspace volatiles. EN data were analyzed using discriminant function analysis (DFA). An overall correct classification rate of pepper varieties by EN of 91% was obtained. A linear correlation between capsaicin, dihydrocapsaicin, and total capsaicinoids and Scoville scores was also observed, and R (2) values of 0.89, 0.85, and 0.91 were obtained, respectively.     

Characterization of Promising Apricot (<Emphasis Type="Italic">Prunus armeniaca</Emphasis> L.) Genetic Resources in Malatya,Turkey

The study here was conducted on nearly 12,000 apricot seedlings in the Malatya Region in the Eastern part of Turkey. This region is famous for its horticulture based mainly on apricot production and the Country's highest apricot production originates from this region. The flower and fruit characteristics of all populations, which include apricot seedlings, in the region were evaluated. Based on their horticultural performances, 13 genotypes were selected, of which seven were considered as apricots served in dried form and six as in table consumption form. Among the selected genotypes, the fruit weight ranged between 28.5 and 71.19 g, soluble solids ranged between 12.7 and 26.5%, while the range in total acidity was between 0.35 and 1.80% and fruit development period was between 87 and 183 days. To determine the selected genotypes performance in a similar environment, they were grafted on to 4-year-old rootstocks. The results from these combinations showed that there was some decrease, especially in fruit size and soluble solids, in the genotypes performance when compared to the results of the initial observations. Some differences were also detected in taste, fruit shape, pit shape, fruit flesh firmness, skin and flesh colors. The dry fruit yield was determined as 22.50–28.36% for the selected dry apricot genotypes. The dry fruit yield of all seven genotypes considered for dry consumption were similar to ‘Hacıhaliloğlu’ and higher than ‘Canino’, which were evaluated as control cultivars.     

Assessing the aromatic potential of Cabernet Sauvignon and Merlot musts used to produce rose wine by assaying the cysteinylated precursor of 3-mercaptohexan-1-ol.

The development of a method for assaying S-3-(hexan-1-ol)-L-cysteine, the cysteinylated precursor of 3-mercaptohexan-1-ol (P-3MH), in must has made it possible to study its impact on the aromatic potential of Merlot and Cabernet Sauvignon grape varieties used to produce rose wines in Bordeaux. The original feature of this method is the purification of very small volumes of must (500 microL) containing P-3MH by affinity chromatography and gas-phase chromatography coupled with mass spectrometry of the purified precursor in trimethylsilylated derivative form. Assays of the cysteinylated precursor in Merlot and Cabernet Sauvignon grapes showed that it was mainly located in the grape skins (60%). Prolonged juice-skin contact increased the must's P-3MH content, and this phenomenon was more marked at higher temperatures. Assessment of the aromatic potential of must used to produce rose wines by chemical analysis of an S-cysteine conjugate is mentioned for the first time.     

Reference evapotranspiration based on Class A pan evaporation via wavelet regression technique

Accurate estimation of reference evapotranspiration (ET₀) is important for water resources engineering. Therefore, a large number of empirical or semi-empirical equations have been developed for assessing ET₀ from numerous meteorological data. However, records of such weather variables are often incomplete or not always available for many locations, which is a shortcoming of these complex models. Therefore, practical and simpler methods are required for estimating the ET₀. In this study, the efficiency of a wavelet regression (WR) model in estimating reference evapotranspiration based on only Class A pan evaporation is examined. The results of the WR model are compared with those of three pan-based equations, namely the FAO-24 pan, Snyder ET₀ and Ghare ET₀ equations and their calibrated versions. Daily Class A pan evaporation data from the Fresno and Bakersfield stations of the United States Environmental Protection Agency in California, USA, are used in the study. The WR model estimates are compared against those of the FAO-56 Penman–Monteith equation. Results showed that the WR model is capable of accurately predicting the ET₀ values as a product of pan evaporation data.     

Effects of varying nitrogen doses on yield,yield components and artemisinin content of Artemisia annua L.

Artemisia annua L. is an aromatic-antibacterial herb that destroys malarial parasites, lowers fevers and checks bleeding, and of which the secondary compound of interest is artemisinin. The objective of the present study was to determine yield, yield components and artemisinin content of A. annua L. grown under four nitrogen applications (0, 40, 80 and 120 kg ha⁻¹) in the Çukurova region of Turkey in 2004 and 2005. Field trials were conducted at Çukurova University, Agricultural Faculty Field Crops Department. In the study, plant height, number of branches, fresh herbage yield, dry herbage yield, fresh leaf yield, dry leaf yield, essential oil content and artemisinin content (by high performance liquid chromatography, HPLC) were examined. By analysis of variance, nitrogen doses had no any statistical effect on the traits investigated except for artemisinin content. Artemisinin content of the dried leaves were significantly affected by nitrogen applications, which varied from 6.32 to 27.50 mg 100 g⁻¹. Contents were from 120 and 80 kg ha⁻¹ nitrogen for the years of 2004 and 2005, respectively.