In vitro antifungal and demelanizing activity of Nepeta rtanjensis essential oil against the human pathogen Bipolaris spicifera

The antifungal activity of Nepeta rtanjensis Diklić & Milojević essential oil was tested against the human pathogenic fungus Bipolaris spicifera (Bainier) Subramanian via mycelial growth assay and conidia germination assay. The minimally inhibitory concentration (MIC) of the oil was determined at 1.0 μg ml-1, while the MIC for the antifungal drug Bifonazole in a positive control was determined at 10.0 μg ml-1. The maximum of conidia germination inhibition was accomplished at 0.6 μg ml-1. In addition, at 0.6 μg ml-1 and 0.8 μg ml-1 the oil was able to cause morphophysiological changes in B. spicifera. The most significant result is the bleaching effect of the melanized conidial apparatus of the test fungi, since the melanin is the virulence factor in human pathogenic fungi. These results showed the strong antifungal properties of N. rtanjensis essential oil, supporting its possible rational use as an alternative source of new antifungal compounds

Comparative study of selected quality parameters of marinated mackerel packed in vacuum and modified atmosphere

Mariniranje je jedan od starijih postupaka konzervisanja ribe i često se primenjuje u Evropi. Ovaj postupak se najčešće koristi za ribe sa većim sadržajem masti, kao što su sardina, skuša, haringa, a ne retko se koristi i za konzervisanje rakova i školjki. Uopšteno govoreći, održivost i bezbednost mariniranih proizvoda od ribe i plodova voda, u koji nije uključena toplotna obrada, zavisi od vrste organske kiseline koja se koristi za mariniranje i koncentracije soli. Poznato je da je pH niži od 4,5 dovoljan da se produži održivost ribe. Međutim, niske pH vrednosti marinade mogu da uzrokuju jak, kiseo ukus. Termin „marinada“ ili „marinirana riba“ se koristi za ribu koja se za mariniranje koristi kao sveža, odmrznuta ili samo soljena, a tretirana je sa jestivim organskim kiselinama, najčešće sirćetnom kiselinom. Marinirana riba se posle završenog mariniranja pakuje najčešće u vakuumu ili modifikovanoj atmosferi, Čime se održivost marinirane ribe produžava. Ambalažiranje hrane, pa i ribe, ima za cilj da potrošačima pruži i osnovne informacije o ribi, a naročito o uslovima čuvanja i o roku trajanja. S tim u vezi, današnju prehrambenu industriju karakteriše posebno razvoj jednog njenog segmenta, a to je pakovanje hrane. Cilj istraživanja u okviru ove doktorske disertacije je bio ispitivanje uticaja pakovanja soljene, odnosno marinirane ribe (skuše) u vakuumu i modifikovanu atmosferu na održivost i odabrane parametre kvaliteta. U eksperimentu je korišćena skuša konzumne veličine (mase od 350-400 grama) koja je obrađena na način uobičajen za industrijski objekat koji se bavi obradom ribe. Riba je obrađena tako da je za soljenje, mariniranje, odnosno, pakovanje korišćen primarno obrađen trup. Riba je podeljena u dve podgrupe, od kojih je jedna podgrupa tretirana samo u slanom rastvoru (10 % soli), a druga podgrupa marinirana u marinadi sa 10 % soli i sa 0,5 % sirćetne kiseline. Tretiranje ribe trajalo je dvadeset četiri sata. Prva podgrupa je podeljena u dve grupe od kojih je jedna pakovana u vakuum (prva grupa), a druga grupa u modifikovanu atmosferu (40 % CO2+60 % N2). Na isti način je podeljena i druga podgrupa i pakovana u vakuum (treća grupa), odnosno modifikovanu atmosferu (40 % CO2+60 % N2) (četvrta grupa). Svi uzorci su skladišteni pri istim kontrolisanim uslovima. Temperatura skladištenja je bila 4 °C. Na početku eksperimenta i na svakih deset dana, tokom pedeset dana, vršene su mikrobiološke (ukupan broj bakterija, ukupan broj enterobakterija, broj psihrotrofa, broj anaerobnih bakterija, broj bakterija mlečne kiseline), hemijske (osnovni hemijski sastav, sadržaj ukupnog isparljivog azota, malondialdehid i histamina), fizičko-hemijske (pH vrednost i aw vrednost) i senzorne analize...The marinating process is one of the oldest preservation methods of fish, and is often used in Europe. This method is commonly used for preservation of the fish with a higher fat content, such as sardines, mackerel, herring, but for the crustaceans and molluscs as well. Generally, shelf life and safety of the marinated fish and seafood, without temperature treatment, depends on the type of organic acid which is used for marinating, and the concentration of salt. It is known that the pH values lower than 4.5 are sufficient to prolong the shelf life of the fish. However, the low pH values of the marinade may cause strong acidic taste. The terms marinade or marinated fish refer to fish products consisting of fresh, frozen, or salted fish or portions of fish treated with an edible organic acid, usually acetic acid. After completing marinating, fish is usually packed in vacuum or modified atmosphere, which is a way to prolong shelf life of marinated fish. The aim of food, including fish labelling is to provide consumers with key information about the fish, and especially on storage conditions and expiration date of the product. In this regard, nowadays, food industry in particular is characterized by the development of food packaging segment. The aim of the study within this PhD thesis was to investigate the influence of packaging of salted and marinated fish (mackerel) in vacuum and modified atmosphere on the shelf life and selected quality parameters. In the experiment it has been used commercial size mackerel (a mass of 350-400 g), which is treated in the manner customary for industrial plant which deals with processing of fish. Fish is processed so that for salting, marinating, and packaging has been used primarily processed fish carcasses. The fish was divided into two subgroups, first which was treated only with saline (10% salt), and a second subgroup which was marinated in a 10% salt and 0.5% acetic acid. The fish was treated for twenty-four hours. The first sub-group is divided into two groups, one of which is packaged in a vacuum (the first group), and the second group in modified atmosphere (40% CO2 + 60% N2). In the same way the other sub-groups were divided and packed in a vacuum (the third group), or a modified atmosphere (40% CO2 + 60% N2) (fourth group)..

Quantum-critical spin dynamics in quasi-one-dimensional antiferromagnets

By means of nuclear spin-lattice relaxation rate 1/T1, we follow the spin dynamics as a function of the applied magnetic field in two gapped one-dimensional quantum antiferromagnets: the anisotropic spin-chain system NiCl2-4SC(NH2)2 and the spin-ladder system (C5H12N)2CuBr4. In both systems, spin excitations are confirmed to evolve from magnons in the gapped state to spinons in the gapples Tomonaga-Luttinger-liquid state. In between, 1/T1 exhibits a pronounced, continuous variation, which is shown to scale in accordance with quantum criticality. We extract the critical exponent for 1/T1, compare it to the theory, and show that this behavior is identical in both studied systems, thus demonstrating the universality of quantum critical behavior

Microwave response of thin niobium films under perpendicular static magnetic fields

The microwave response of high quality niobium films in a perpendicular static magnetic field has been investigated. The complex frequency shift was measured up to the upper critical fields. The data have been analyzed by the effective conductivity model for the type-II superconductors in the mixed state. This model is found to yield consistent results for the coherence lengths in high-kappa superconducting samples, and can be used with HTSC even at temperatures much below T_c. It is shown that for samples with high values of depinning frequency, one should measure both components of the complex frequency shift in order to determine the flow resistivity. The thick Nb film (160 nm) has low resistivity at 10 K, comparable to the best single crystals, and low kappa value. In contrast, the thinnest (10 nm) film has kappa ~ 9.5 and exhibits a high depinning frequency (~20 GHz). The upper critical field determined from microwave measurements is related to the radius of nonoverlaping vortices, and appears to be larger than the one determined by the transition to the normal state.Comment: 8 pages, 7 figures; submitted to PRB; measured rho_n; changes due to the referees' comments (abstract, conclusions, extended introduction

Household food waste in Belgrade - sin and unconcern

The aim of this study was to examine the actual procedures with food in households and consumer attitudes about food waste. The survey was conducted in 83 households in Belgrade, Serbia. All participants were interviewed using a standardized questionnaire. The results obtained show that awareness of food waste is at a satisfactory level, but the actual situation is that food is discarded in large quantities, even though people are aware of what a global problem this is. Large contradictions were observed among the respondents answers in this study. Respondents who stated that they never discard food, in further responses, declared they throw away significant amounts of food for various reasons (too long storage, overconsumption, improper preparation, etc.). We conclude that people are either unaware of how much food they discard, or they do not want to admit it to themselves. However, participants largely have a sense of guilt about discarding food. This indicates consumer awareness of food waste, and is an encouraging sign that further education could be effective in consumers taking into account their food waste habits, starting from procurement planning, through storage and preparation

Variability of Quantitative and Qualitative Characteristics of Fagus sylvatica ‘Purpurea’ Clones Produced by Grafting

European beech is renowned due to its ornamental cultivars, such as purple beech (Fagus sylvatica ‘Purpurea’), but its production in Serbia is represented in small number of nurseries. The aim of this paper was to analyze the success of hetero-vegetative propagation of purple beech and variability of different characteristics, in order to improve the production of nursery stocks for widespread use. The splice and wedge grafting were applied, using scions collected from five Fagus sylvatica ‘Purpurea’ adult trees, and two different rootstocks: five-year-old seedlings directly produced in nursery beds and one-year-old containerized seedlings. Analysis of grafting success rates, survival percentage, as well as quantitative (height and root collar diameter) and qualitative (leaf color) characteristics of produced grafts in four successive years, were investigated. Grafting performed using the containerized rootstocks showed the high success rate (50-80%), but the survival percentage at the end of fourth year was lower (30-47%). The survival percentage of grafts produced directly on rootstocks in nursery beds was 22-78% at the end of first year, and constantly kept those values in the next three years. The highest mean values of quantitative characteristics were found in clone number 5 and 1, while the smallest were recorded in clone 3. Leaf color was intensive reddish-purple in most grafts, while in some grafts about 20% reddish-green leaves was recorded. Based on the obtained results, it can be stated that purple beech trees in Belgrade area could be used as mother plants and starting material for the improvement of its production

Complex evolutionary dynamics of massively expanded chemosensory receptor families in an extreme generalist chelicerate herbivore

While mechanisms to detoxify plant produced, anti-herbivore compounds have been associated with plant host use by herbivores, less is known about the role of chemosensory perception in their life histories. This is especially true for generalists, including chelicerate herbivores that evolved herbivory independently from the more studied insect lineages. To shed light on chemosensory perception in a generalist herbivore, we characterized the chemosensory receptors (CRs) of the chelicerate two-spotted spider mite, Tetranychus urticae, an extreme generalist. Strikingly, T. urticae has more CRs than reported in any other arthropod to date. Including pseudogenes, 689 gustatory receptors were identified, as were 136 degenerin/Epithelial Na+ Channels (ENaCs) that have also been implicated as CRs in insects. The genomic distribution of T. urticae gustatory receptors indicates recurring bursts of lineage-specific proliferations, with the extent of receptor clusters reminiscent of those observed in the CR-rich genomes of vertebrates or C. elegans. Although pseudogenization of many gustatory receptors within clusters suggests relaxed selection, a subset of receptors is expressed. Consistent with functions as CRs, the genomic distribution and expression of ENaCs in lineage-specific T. urticae expansions mirrors that observed for gustatory receptors. The expansion of ENaCs in T. urticae to > 3-fold that reported in other animals was unexpected, raising the possibility that ENaCs in T. urticae have been co-opted to fulfill a major role performed by unrelated CRs in other animals. More broadly, our findings suggest an elaborate role for chemosensory perception in generalist herbivores that are of key ecological and agricultural importance

Spectral changes of brain activity in rat offspring exposed to aluminium during gestation and lactation

Exposure to aluminium during gestation causes changes in mammalian brain development and behavior. Our aim was to perform spectral analysis on electrocortical activity of Sprague Dawley male pups (30±3 days of age) whose mothers were treated with aluminium during gestation and lactation. There was a higher presence of power spectra in the delta range of parietal electrocortical activity, a lower presence in the theta range and increased values of the parameter DT as the ratio of delta to theta range in pups indirectly exposed to aluminium (whose mothers were drinking a 0.5% water solution of aluminium chloride during the gestation and lactation periods), compared to controls