Toward a harmonized and standardized protocol for the determination of total hydroxytyrosol and tyrosol content in virgin olive oil (VOO). The pros of a fit for the purpose ultra high performance liquid chromatography (UHPLC) procedure

\u3a4oward a harmonized and standardized procedure for the determination of total hydroxytyrosol and tyrosol content in virgin olive oil (VOO), the pros of a recently published in house validated ultra high performance liquid chromatography (UHPLC) protocol are discussed comparatively with those of other procedures that determine directly or indirectly the compounds hosted under the health claim on "olive oil polyphenols" (EC regulation 432/2012). Authentic VOOs were analyzed with five different liquid chromatographic separation protocols and 1H-NMR one in five different laboratories with expertise in VOO phenol analysis within three months. Data comparison indicated differences in absolute values. Method comparison using appropriate tools (Passing-Bablok regression and Bland Altman analyses) for all protocols vs. the UHPLC one indicated slight or statistically significant differences. The results were also discussed in terms of cost effectiveness, detection means, standard requirements and ways to calculate the total hydroxytyrosol and tyrosol content. Findings point out that the in-house validated fit for the purpose UHPLC protocol presents certain pros that should be exploited by the interested parties. These are the simplicity of sample preparation, fast elution time that increase the number of samples analyzed per day and integration of well-resolved peaks with the aid of only two commercially available external standards. Importance of correction factors in the calculations is stressed

Peri-articular histiocytic sarcoma in Bernese Mountain Dogs : a retrospective investigation of the prevalence of this tumour in association with previously diseases joints

C

Redefinition of Aureobasidium pullulans and its varieties

Using media with low water activity, a large numbers of aureobasidium-like black yeasts were isolated from glacial and subglacial ice of three polythermal glaciers from the coastal Arctic environment of Kongsfjorden (Svalbard, Spitsbergen), as well as from adjacent sea water, sea ice and glacial meltwaters. To characterise the genetic variability of Aureobasidium pullulans strains originating from the Arctic and strains originating pan-globally, a multilocus molecular analysis was performed, through rDNA (internal transcribed spacers, partial 28 S rDNA), and partial introns and exons of genes encoding β-tubulin (TUB), translation elongation factor (EF1α) and elongase (ELO). Two globally ubiquitous varieties were distinguished: var. pullulans, occurring particularly in slightly osmotic substrates and in the phyllosphere; and var. melanogenum, mainly isolated from watery habitats. Both varieties were commonly isolated from the sampled Arctic habitats. However, some aureobasidium-like strains from subglacial ice from three different glaciers in Kongsfjorden (Svalbard, Spitsbergen), appeared to represent a new variety of A. pullulans. A strain from dolomitic marble in Namibia was found to belong to yet another variety. No molecular support has as yet been found for the previously described var. aubasidani. A partial elongase-encoding gene was successfully used as a phylogenetic marker at the (infra-)specific level

Adaptation of extremely halotolerant black yeast Hortaea werneckii to increased osmolarity: a molecular perspective at a glance

Halophilic adaptations have been studied almost exclusively on prokaryotic microorganisms. Discovery of the black yeast Hortaea werneckii as the dominant fungal species in hypersaline waters enabled the introduction of a new model organism to study the mechanisms of salt tolerance in eukaryotes. Its strategies of cellular osmotic adaptations on the physiological and molecular level revealed novel, intricate mechanisms to combat fluctuating salinity. H. werneckii is an extremely halotolerant eukaryotic microorganism and thus a promising source of transgenes for osmotolerance improvement of industrially important yeasts, as well as in crops

Is there a common water-activity limit for the three domains of life?

Archaea and Bacteria constitute a majority of life systems on Earth but have long been considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic prokaryotes are known for an ability to multiply at saturated NaCl (water activity (a w) 0.755) some xerophilic fungi can germinate, usually at high-sugar concentrations, at values as low as 0.650-0.605 a w. Here, we present evidence that halophilic prokayotes can grow down to water activities of <0.755 for Halanaerobium lacusrosei (0.748), Halobacterium strain 004.1 (0.728), Halobacterium sp. NRC-1 and Halococcus morrhuae (0.717), Haloquadratum walsbyi (0.709), Halococcus salifodinae (0.693), Halobacterium noricense (0.687), Natrinema pallidum (0.681) and haloarchaeal strains GN-2 and GN-5 (0.635 a w). Furthermore, extrapolation of growth curves (prone to giving conservative estimates) indicated theoretical minima down to 0.611 a w for extreme, obligately halophilic Archaea and Bacteria. These were compared with minima for the most solute-tolerant Bacteria in high-sugar (or other non-saline) media (Mycobacterium spp., Tetragenococcus halophilus, Saccharibacter floricola, Staphylococcus aureus and so on) and eukaryotic microbes in saline (Wallemia spp., Basipetospora halophila, Dunaliella spp. and so on) and high-sugar substrates (for example, Xeromyces bisporus, Zygosaccharomyces rouxii, Aspergillus and Eurotium spp.). We also manipulated the balance of chaotropic and kosmotropic stressors for the extreme, xerophilic fungi Aspergillus penicilloides and X. bisporus and, via this approach, their established water-activity limits for mycelial growth (∼0.65) were reduced to 0.640. Furthermore, extrapolations indicated theoretical limits of 0.632 and 0.636 a w for A. penicilloides and X. bisporus, respectively. Collectively, these findings suggest that there is a common water-activity limit that is determined by physicochemical constraints for the three domains of life

Controlling microbial infection by managing grapevine canopy

Pinots (Vitis vinifera L.) are known as tight-clustered grape varieties, where the mechanical pressure of adjacent berries may disrupt cuticle waxes, thus predisposing these sites to greater incidences of infection. One of the main causes of crop quality degradation is grape rot due to the development of various microorganisms (bacteria, yeasts or other fungi). Among them Botrytis cinerea is one of the most frequent problems. Because mold spores are ubiquitous, the control of germination and growth in the vineyard by use of fungicides may only be part of the solution. Therefore, carefully selected cultural practices may play a significant role toward encouraging or discouraging mold and other microbial infections. A field trial was established in Pinot Noir vineyard of Vipava Valley for two consecutive years. Preliminary results based on visual examination of microbial compromised grapes indicated that earlier leaf removal treatments reduced the extent of microbe damage on grape. Therefore in the following harvest three different treatments of leaf removal (at pre-flowering, berry-set and veraison phase of grape development) were performed, using untreated vines as a control. Temperature and humidity data were collected in the grape area of all treatments. Microbial population on grapes was followed using standard cultivation methods during ripening and at harvest time as well as visual inspection of damaged / sound grapes was performed at both times. At harvest time compactness of grapes was also evaluated. Parallel trial with excluding last Switch® application was done to evaluate the effect in different treatments. In general we observed the change in species composition on the surface of grapes with early predominance by the basidiomycetous yeasts and species Aureobasidium pullulans, and at harvest time with the prevalence of the ascomycetous yeasts, lactic / acetic acid bacteria and molds. Leaf removal was much more effective against Botrytis Cinerea compering to additional Switch® application, especially at leaf removals at earlier stages. Pre-flowering leaf removal also showed significant reduction of grape compactness. The results suggesting early leaf removals as successful tool for reducing the risk of microbial infections

Experiences in olive oil purity and quality assessment as a tool for pumpkin seed oil evaluation. What can consumers benefit?

Olive and pumpkin seed oils play a specific role in Slovenian edible oil market. That is why exact and accurate tools for assessing the oils’ quality and purity (adulteration) are needed. One of the tools is registering certain names and foodstuffs in National registers and the Register of European Union. Another tool is the analysis which can help to assess the characteristics of the oil and to classify it in categories. In the field of olive oils, this has been done excellently with the European Commission regulations. In the present work we tried to test few pumpkin seed oils for fatty acids content, trans isomers of fatty acids, composition of sterols and tocopherols. The main goal was to check the purity of the oils and understand the present situation in the field. The analytical results show that some samples are adulterated with seed oils. What can consumers benefit? From the Slovenian olive oil experience it can be concluded that the path towards better quality oils does not strictly follow analytical methods but tries to track well-established rules and definitions of quality and purity. The consumers must learn and be aware that the quality and purity can be analytically proven