Quantitative bioluminometric method for DNA-based species/varietal identification in food authenticity assessment

A method is reported for species quantification by exploiting single-nucleotide polymorphisms (SNPs). These single-base changes in DNA are particularly useful because they enable discrimination of closely related species and/or varieties. As a model, quantitative authentication studies were performed on coffee. These involved the determination of the percentage of Arabica and Robusta species based on a SNP in the chloroplastic trnL(UAA)-trnF(GAA) intraspacer region. Following polymerase chain reaction (PCR), the Robusta-specific and Arabica-specific fragments were subjected to 15 min extension reactions by DNA polymerase using species-specific primers carrying oligo(dA) tags. Biotin was incorporated into the extended strands. The products were captured in streptavidin-coated microtiter wells and quantified by using oligo(dT)-conjugated photoprotein aequorin. Aequorin was measured within 3 s via its characteristic flash-type bioluminescent reaction that was triggered by the addition of Ca(2+). Because of the close resemblance between the two DNA fragments, during PCR one species serves as an internal standard for the other. The percentage of the total luminescence signal obtained from a certain species was linearly related to the percent content of the sample with respect to this species. The method is accurate and reproducible. The microtiter well-based assay configuration allows high sample throughput and facilitates greatly the automation.     

Temperature Preference of Early Developmental Stages of Pagellus erythrinus

Pagellus erythrinus culture was carried out from the fertilizable egg to the larval stage at different temperatures: 15°, 18°, and 21°C for the embryonic stage and 16°, 18°, and 21°C for yolk-sac and larval stages. Total length and variability, growth rate, duration of each stage, hatching percentage, survival of each developmental stage, efficiency of vitelline and lipid utilization, and the percentages of morpho-anatomical abnormalities were used as criteria for the evaluation of temperature's influence on culture of Pagellus erythrinus. A temperature of 18°C favors the early life stages culture of Pagellus erythrinus.     

Storage of olives (Olea europaea L.) under CO2 atmosphere: liquid chromatography-mass spectrometry characterization of indices related to changes in polyphenolic metabolism

Olives (Olea europaea cv. Chondrolia) were stored under a CO2 atmosphere immediately after harvesting for a period of 12 days. Samples obtained at 24-h intervals were analyzed by HPLC to identify components that may reflect changes in the biochemical behavior of the tissue. Four substances were shown to undergo significant fluctuations during storage, while their evolution was found to be different in olives stored under CO2 from those stored under regular atmospheric conditions (control). On the basis of data provided by liquid chromatography-electrospray ionization mass spectrometry, these substances were tentatively identified as hydroxytyrosol glucoside, demethylated ligstroside aglycone, ibotalactone A methyl ester, and verbascoside. The data are discussed in relation to the effect of postharvest treatments of olives for purposes of manipulating their polyphenolic content and plausible development of novel debittering processes.     

First record of Dryocosmus kuriphilus in Greece

After the first introduction of chestnut gall wasp, Dryocosmus kuriphilus, in Italy, it has spread rapidly in several other European countries, probably largely due to trade in chestnut plants. Despite the measures taken to prevent further spread of this pest to other countries, D. kuriphilus was detected in Greece for the first time in 2014. However, surveys have shown that the pest is still of very limited distribution in Greece. Having faced the damage caused by chestnut blight (Cryphonectria parasitica) over the last 50 years, the production of chestnuts in Greece is now seriously threatened by chestnut gall wasp, which has already caused extensive losses in chestnut production of other countries. In order to minimize the impact of chestnut gall wasp, control measures are being designed involving the release of the parasitoid Torymus sinensis.     

Towards sweet cherry (<Emphasis Type="Italic">Prunus avium</Emphasis> L.) breeding: phenotyping evaluation of newly developed hybrids

An increasing demand for cherry production (Prunus avium L.) in Greece led to the development of new high quality sweet cherry cultivars. Self-incompatibility in cherry is one of the most challenging issues for the species’ cultivation and top breeding priority. Τhe present study focuses on the development of new hybrids with improved traits such as productivity, fruit size, organoleptic characteristics and self-compatibility. For this purpose, thirty different cultivars were crossed and produced hybrids that were evaluated according to 34 morpho-physiological characteristics. The results were analyzed using the XLSTAT (version 2014.1) software and a dendrogram was constructed using the agglomerative hierarchical clustering method. Optimal hybrid clustering was achieved when characteristics of great economic importance such as fruit shape and size, growth habit and days to blooming were included in the analysis. Based on the results, new sweet cherry hybrids with the special character of self-compatibility were developed. Our findings provide crucial new information for sweet cherry future breeding programs and cultivation.     

Data on the ecology of <Emphasis Type="Italic">Kermes echinatus</Emphasis> Balachowsky (Hemiptera,Coccomorpha, Kermesidae) on <Emphasis Type="Italic">Quercus ilex</Emphasis> (Fagaceae) in Greece

The Phenology and natural enemies of the scale insect Kermes echinatus Balachowsky (Hemiptera: Kermesidae), which infests the holly oak Quercus ilex (Fagaceae), were studied between November 2015 and November 2017, in southern Greece (Kalamata, Peloponnese). Kermes echinatus is a univoltine, oviparous and biparental species. It overwinters as 1st instar nymphs, settling on the branches of the trees. The second instar nymphs appear by the middle of April, followed by 3rd instar nymphs until the end of May. The male larvae and pupae were recorded from the end of April to the end of May. Mature females, pre-ovipositing and ovipositing adults, were recorded during May and June. The newly hatched crawlers appeared by the end of June, which remained at this stage, settled on branches during the rest of summer and winter periods till next April. The parasitoid species Metaphycus gennaroi Guerrieri & Noyes and the hyperparasite Cheiloneurus claviger Thomson (Hymenoptera: Encyrtidae) were recorded on the colonies of the scale. The parasitism level of the scale reached to 21%. The predator Chilocorus bipustulatus L. (Coleoptera: Coccinellidae) was also recorded on the colonies of the scale.     

Bacterial communities in the rhizosphere of Phragmites australis from an oil-polluted wetland

Although Phragmites australis is commonly planted in constructed wetlands, very little is known about its roots-associated bacterial communities, especially in wetlands used for the remediation of oil produced waters. Here, we describe the bacterial diversity, using molecular (illumina MiSeq sequencing) and cultivation techniques, in the rhizosphere soils of P. australis from an oil-polluted wetland in Oman. The obtained isolates were tested for their plant-growth promoting properties. Most sequences belonged to Proteobacteria, Bacteriodetes and Firmicutes. Sequences of potential hydrocarbon-degrading bacteria (e.g. Ochrobactrum, and Pseudomonas) were frequently encountered. All soils contained sequences of known sulfur-oxidizing (e.g. Thiobacillus, Thiofaba, Rhodobacter and Sulfurovum) and sulfate-reducing bacteria, although the latter group made up only 0.1% to 3% of total sequences. The obtained isolates from the rhizosphere soils were phylogenetically affiliated to Serratia, Acinetobacter, Xenorhabdus, Escherichia and Salmonella. All strains were able to solubilize phosphate and about half were capable of producing organic acids and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Around 42% of the strains had the ability to produce indole acetic acid and siderophores. We conclude that the rhizosphere soils of P. australis in oil polluted wetlands harbor diverse bacterial communities that could enhance the wetland performance through hydrocarbon degradation, nutrient cycling and supporting plant growth.     

Evaluation of a portable glucose meter for use in cattle and sheep

Background: In farm animal practice, determination of blood glucose concentration under field conditions is often necessary. Objective: As there is no portable glucose meter device developed for use in farm animals, the analytical accuracy of a portable glucometer designed for people was evaluated for its use in cattle and sheep. Methods: Blood samples from 90 cattle and 101 sheep were used in the study. Glucose concentration was determined in whole blood immediately after blood collection from the jugular vein with the One Touch Vita portable glucometer and in serum with an enzymatic colorimetric method. The agreement between methods was assessed by Passing and Bablok regression analysis. The precision and the accuracy of the measurements were determined using the concordance correlation coefficient. Results: There was a strong linear relationship between the glucose values obtained using the portable glucometer and those obtained by the bench method in both cattle and sheep. Precision was 95% for cattle and 88% for sheep, whereas accuracy was 92% and 99%, respectively. The mean glucose values obtained using the portable glucometer were significantly lower by 8.3% in cattle and 3.2% in sheep than those determined by the bench method. Conclusion: The One Touch Vita portable glucometer can be used in clinical practice to determine blood glucose concentrations in cattle and sheep, but reference intervals (RI) must be corrected to allow for negative bias. Based on these equations the RI for blood glucose in cattle and sheep using the portable glucometer were corrected to 1.84–4.17 and 2.41–4.35 mmol/L, respectively.