Glycerin as a factor for moderating quality changes in table eggs during storage

Glycerol, a by-product of biodiesel production, is non-toxic to humans and the environment. With the current increase in the demand for fuels obtained from biomass, the amount of glycerine waste production is increasing. There are many ways to dispose this substance (in pharmaceuticals, cosmetics, and in chemical industry), but its utilization is still insufficient. Therefore, the aim of this study was to assess the possibility of limiting quality changes in table eggs during storage by coating the shells with a glycerol solution. The material used in this research consisted of 270 table chicken eggs collected on the same day. On the first day of the experiment, quality traits of 30 eggs were evaluated (initial control group). The remaining 240 eggs were divided into two equal groups: control (eggs that were not subjected to any treatment) and experimental (eggs that were coated with a 5&thinsp;% aqueous solution of glycerol). The eggs were placed on transport trays and stored at 14&thinsp;°C and 70&thinsp;% humidity. Quality evaluations were carried out after 14 and 28 days of storage. The depth of the air cell, mass and specific gravity of the egg, the shell characteristics (water vapour conductance, strength, mass, thickness, and density), and the content traits (pH of the albumen and yolk, Haugh units, and colour and weight of the yolk) were evaluated. The results obtained suggest that the use of glycerine may contribute to slowing adverse changes in egg quality during storage by limiting CO2 removal from the egg content, which allows the egg to maintain albumen structure. Due to the fact that glycerine is a safe, cheap, and easy-to-apply substance, its large-scale use in poultry raw material storage seems to be a very real possibility.</p

Insights into the Transposable Mobilome of Paracoccus spp. (Alphaproteobacteria)

Several trap plasmids (enabling positive selection of transposition events) were used to identify a pool of functional transposable elements (TEs) residing in bacteria of the genus Paracoccus (Alphaproteobacteria). Complex analysis of 25 strains representing 20 species of this genus led to the capture and characterization of (i) 37 insertion sequences (ISs) representing 9 IS families (IS3, IS5, IS6, IS21, IS66, IS256, IS1182, IS1380 and IS1634), (ii) a composite transposon Tn6097 generated by two copies of the ISPfe2 (IS1634 family) containing two predicted genetic modules, involved in the arginine deiminase pathway and daunorubicin/doxorubicin resistance, (iii) 3 non-composite transposons of the Tn3 family, including Tn5393 carrying streptomycin resistance and (iv) a transposable genomic island TnPpa1 (45 kb). Some of the elements (e.g. Tn5393, Tn6097 and ISs of the IS903 group of the IS5 family) were shown to contain strong promoters able to drive transcription of genes placed downstream of the target site of transposition. Through the application of trap plasmid pCM132TC, containing a promoterless tetracycline resistance reporter gene, we identified five ways in which transposition can supply promoters to transcriptionally silent genes. Besides highlighting the diversity and specific features of several TEs, the analyses performed in this study have provided novel and interesting information on (i) the dynamics of the process of transposition (e.g. the unusually high frequency of transposition of TnPpa1) and (ii) structural changes in DNA mediated by transposition (e.g. the generation of large deletions in the recipient molecule upon transposition of ISPve1 of the IS21 family). We also demonstrated the great potential of TEs and transposition in the generation of diverse phenotypes as well as in the natural amplification and dissemination of genetic information (of adaptative value) by horizontal gene transfer, which is considered the driving force of bacterial evolution

Competitive outcome of Daphnia-Simocephalus experimental microcosms: salinity versus priority effects

Competition is a major driving force in freshwaters, especially given the cyclic nature and dynamics of pelagic food webs. Competition is especially important in the initial species assortment during colonization and re-colonization events, which depends strongly on the environmental context. Subtle changes, such as saline intrusion, may disrupt competitive relationships and, thus, influence community composition. Bearing this in mind, our objective was to assess whether low salinity levels (using NaCl as a proxy) alter the competitive outcome (measured as the rate of population biomass increase) of Daphnia-Simocephalus experimental microcosms, taking into account interactions with priority effects (sequential species arrival order). With this approach, we aimed to experimentally demonstrate a putative mechanism of differential species sorting in brackish environments or in freshwaters facing secondary salinization. Experiments considered three salinity levels, regarding NaCl added (0.00, 0.75 and 1.50 g L(-1)), crossed with three competition scenarios (no priority, priority of Daphnia over Simocephalus, and vice-versa). At lower NaCl concentrations (0.00 and 0.75 g L(-1)), Daphnia was a significantly superior competitor, irrespective of the species inoculation order, suggesting negligible priority effects. However, the strong decrease in Daphnia population growth at 1.50 g L(-1) alleviated the competitive pressure on Simocephalus, causing an inversion of the competitive outcome in favour of Simocephalus. The intensity of this inversion depended on the competition scenario. This salinity-mediated disruption of the competitive outcome demonstrates that subtle environmental changes produce indirect effects in key ecological mechanisms, thus altering community composition, which may lead to serious implications in terms of ecosystem functioning (e.g. lake regime shifts due to reduced grazing) and biodiversity

Narażenie zawodowe leśników na DEET – badania ankietowe, analiza

Foresters, considering the character of their work, are exposed to the occurrence of many types of diseases. The main occupational risk among forestry workers is caused by infectious pathogens, the main reservoir of which are wild animals, and the vector are ticks. Forestry workers are exposed to the effect of repellents, including DEET (N,N-diethyl-m-toluamide) in association with protection against tick and mosquito bites. The goal of the project was to discover the amount of DEET identified in the samples of sweat and urine from the foresters who use chemical agents repelling insects. The study covered 22 foresters from the Janow Lubelski Forest District, and 10 individuals who constituted a control group. Questionnaires concerning the use of repellents, and urine samples were collected (2 from each person in the study), as well as sweat samples (4 each). Each collected biological sample was properly prepared and subjected to chromatographic analysis (GC/MS) for the identification of DEET. The season of repellents use is from March–October, or even November. The highest intensity of the use of repellents (as many as 5 days a week) is during the period from May–July. The chromatographic analyses performed did not show even the lowest content of DEET in the collected biological samples from both the control group and foresters. The absence of DEET in the foresters’ urine may be explained by the late date of collection of the samples – in October, when they no longer use repellents, or use them very rarely. The studies conducted within this project allowed the observation that DEET is not accumulated, is subject to quick elimination from the body, which favourably affects the safety of its use. Exposure to chemical occupational hazards in forest areas is an underestimated problem of occupational medicine and public health, which has not been fully explored.Leśnicy z uwagi na charakter wykonywanej pracy narażeni są na występowanie różnego typu chorób. Głównym zagrożeniem zawodowym dla pracowników leśnictwa są patogeny zakaźne, których głównym rezerwuarem są dzikie zwierzęta, a wektorem kleszcze. Pracownicy leśnictwa są narażeni na działanie repelentów w tym DEET (N,N-dietylo-m-toluamid) w związku z ochroną przed ukłuciami kleszczy i komarów. Celem projektu było poznanie, jaka ilość DEET zostanie zidentyfikowana w próbkach potu i moczu pochodz ących od leśników, którzy stosują środki chemiczne odstraszające owady. W badaniach wzięło udział 22 leśników Nadleśnictwa Janów Lubelski oraz 10 osób stanowiących grupę kontrolną. Zostały zgromadzone ankiety dotyczące stosowania repelentów oraz zostały zebrane próbki moczu (po 2 od każdej osoby badanej) i próbki potu (po 4). Każda z zebranych próbek biologicznych została odpowiednio przygotowana i poddana analizie chromatograficznej (GC/MS) celem identyfikacji w nich DEET. Sezon stosowania repelentów przypada na okres od marca do października, a nawet listopada. Największe natężenie stosowania repelentów (bo aż 5 dni w tygodniu) przypada na okres od maja do lipca. Przeprowadzone badania chromatograficzne nie wykaza ły nawet najmniejszej zawartości DEET w zgromadzonych próbkach biologicznych pochodzących zarówno od grupy kontrolnej, jak i od leśników. Brak obecności DEET w moczu leśników należy tłumaczyć późnym terminem zbiorem próbek – w październiku, kiedy leśnicy nie stosują już repelentów lub stosują bardzo rzadko. Badania przeprowadzone w tym projekcie pozwoliły zaobserwować, że DEET nie jest akumulowany, podlega szybkiej eliminacji z organizmu, co wpływa korzystnie na bezpieczeństwo jego stosowania. Ekspozycja na chemiczne zagrożenia zawodowe na obszarach leśnych jest niedocenionym i nie do końca zbadanym problemem medycyny pracy i zdrowia publicznego

Lighting in the shackling area: conciliating broiler welfare with labor comfort

The objective of this study was to investigate if blue lighting could reduce broiler stress and comply with legal labor comfort requirements in a new shackling area of a middle-size processing plant. In this study, the old shackling area was compared with the new area, where a blue lighting system was designed and implemented according to the regulations. The old and new areas were video- and audio-recorded during the shackling of 33,850 broilers in each area. Data were statistically analyzed using the non-parametric test of Wilcoxon-Mann-Whitney (w test).The results indicated 56% reduction in wing-flapping and 3.2% noise reduction in the new area. These results were obtained by increasing 119% lighting at the work stations in the shackling area, allowing workers to handle the birds more carefully, which may improve processing plant productivity. The study demonstrated that it is possible to conciliate better animal welfare with visual comfort for workers in the shackling area