Quantifying the individual effects of ethanol and temperature on the fitness advantage of Saccharomyces cerevisiae

The presence of Saccharomyces cerevisiae in grape berries and fresh musts is usually very low. However, as fermentation progresses, the population levels of this species considerably increase. In this study, we use the concept of fitness advantage to measure how increasing ethanol concentrations (0-25%) and temperature values (4-46 °C) in wine fermentations affects competition between S. cerevisiae and several non-Saccharomyces yeasts (Hanseniaspora uvarum, Torulaspora delbrueckii, Candida zemplinina, Pichia fermentans and Kluyveromyces marxianus). We used a mathematical approach to model the hypothetical time needed for S. cerevisiae to impose itself on a mixed population of the non-Saccharomyces species described above. This approach also took into consideration the influence of environmental factors and the initial population levels of S. cerevisiae (0.1, 1.0 and 10.0%). Our results suggest that Saccharomyces niche construction via ethanol production does not provide a clear ecological advantage (at least not until the ethanol concentration exceeds 9%), whereas a temperature rise (above 15 °C) does give S. cerevisiae a considerable advantage. The initial frequency of S. cerevisiae considerably influences the time it needs to impose itself (until it reaches a final frequency of 99% in the mixed culture), the lowest time values being found at the highest initial frequency. In light of these results, the application of low temperatures in the wine industry could favor the growth and survival of non-Saccharomyces species for a longer period of time.     

Assessment via the modified gompertz-model reveals new insights concerning the effects of ionic liquids on biohydrogen production

Lignocellulosic biofuel, in particular hydrogen gas production is governed by successful feedstock pretreatment, hydrolysis and fermentation. In these days, remarkable attention is paid to the use of ionic liquids to make the fermentable regions of lignocellulose biomass more accessible to the biocatalysts. Although these compounds have great potential for this purpose, their presence during the consecutive fermentation stage may pose a threat on process stability due to certain toxic effects. This, however, has not been specifically elaborated for dark fermentative biohydrogen generation. Hence, in this work, two common imidazolium-type ionic liquids (1-butyl-3-methylimidazolium acetate, ([bmim][Ac]) and 1-butyl-3-methylimidazolium chloride, ([bmim][Cl])) were employed in mixed culture biohydrogen fermentation to investigate the possible impacts related to their presence and concentrations. The batch assays were evaluated comparatively via the modified Gompertz-model based on the important parameters characterizing the process, namely the biohydrogen production potential, maximum biohydrogen production rate and lag-phase time.     

A rat model for functional characterization of pregnancy-induced denervation and postpartum reinnervation in the myometrium and cervix: a superfusion study

The pregnancy-induced rapid degeneration of the adrenergic nerves innervating the uterus is a well-known but poorly understood phenomenon. Since most of the published investigations were carried out by histological assay, our aim was to describe the loss of the adrenergic function during pregnancy and the re-innervational procedure in the postpartum period. Myometrial and cervical samples from rats were loaded with [3H]noradrenaline and then transferred into a chamber for superfusion. After a wash-out period, fractions were collected. The fifth and fifteenth fraction tissues were stimulated with an electric field. The [3H]noradrenaline contents of the fractions were determined, together with the amount remaining in the tissue. The myometrial [3H]noradrenaline release was substantially decreased in early pregnancy, and absent in the late stage. Differences in release profile were detected between the implantation sites and the interimplantation areas. As a refinement of the results of previous histochemical studies, the noradrenergic functions of the cervix were found to be deeply affected in the early postpartum period. The pregnancy-induced denervational procedure can be followed by means of a superfusional technique after [3H]noradrenaline loading. As our technique is considered to be similar in sensitivity to histological methods, superfusion can be regarded as a model for functional investigations of pregnancy-induced denervation.     

Characterization of Spanish honeys with protected designation of origin "Miel de Granada" according to their mineral content

Honey attributes such as geographical origin or specified botanical sources often command a premium price due to their organoleptic or pharmacoactive properties. "Miel de Granada" is a highly quality product with protected designation of origin (PDO) which includes six monofloral honeys and two multifloral honeys. Our objective was the characterization of "Miel de Granada" according to their metal content. Metal content was specific enough and allowed discrimination from honeys of different botanical and geographical origins and confirmed the authenticity of PDO labelling as Granada product with the determination of only five elements (K, Na, Ca, Mg and Zn). Chemometric techniques as cluster analysis and ANOVA were used to classify honeys according to their botanical and geographical origin in the metal data. Metal content marks the differences in honey samples and can be used as a tool to assess the quality of honeys. ANOVA showed significant differences among rosemary honeys from different geographical areas despite the botanical factor weight. Our research contributes to the groundwork studies to determine the geographical origin of Spanish honeys.     

Quality assessment of tomato landraces and virus-resistant breeding lines: quick estimation by near infrared reflectance spectroscopy

BACKGROUND: Several tomato landraces are very popular in south‐eastern Spain for their organoleptic fruit quality, but these cultivars are highly susceptible to several viruses. A breeding programme is being carried out for the introduction of virus resistances into these landraces. In the last steps of our breeding programme a high number of breeding lines must be evaluated for agronomic and organoleptic quality parameters. Near infrared reflectance spectroscopy (NIRS) technology shows considerable promise and is ideally suited to the requirements of breeders. RESULTS: Significant differences between a set of 35 tomato breeding lines, seven landraces and one commercial hybrid were observed for quality and mineral content parameters, suggesting that there are considerable levels of genetic diversity between the cultivar groups studied. Using NIRS on dry samples of tomato constitutes a feasible technique to estimate the content of several minerals (C, N, P, K, Ca, Na, Mn, Mg and Cu) according to the coefficient of determination for calibration (R² > 0.90). NIRS estimations of soluble solids content and titratable acidity obtained were considered useful only for general screening purposes. CONCLUSIONS: NIRS technology may be a useful tool in the selection of lines coming out of tomato breeding programs, allowing a quick estimation of mineral content. However, the estimation of soluble solids content and titratable acidity by NIRS must be improved. Copyright © 2011 Society of Chemical Industry     

Salmonellosis in finishing pigs in Spain: prevalence, antimicrobial agent susceptibilities, and risk factor analysis

A herd-based survey of Salmonella in pigs was carried in a major pig producing region of Spain. Mesenteric lymph nodes were collected from the carcasses of 25 pigs from each of 80 herds at time of slaughter. Salmonella spp. were isolated from 31% of animals and 94% of herds. Within-herd prevalence ranged from 4 to 88%, with the prevalence in most herds being greater than 10%. A large diversity of Salmonella serotypes was found, with Typhimurium, 4,[5],12:i:-, and Rissen being the most prevalent. Two or more serotypes coexisted in 73% of the herds. Salmonella Typhimurium was present in 68% of the herds. Most (82%) of the Salmonella isolates belonged to serogroups targeted by enzyme-linked immunosorbent assay tests for pig salmonellosis. Resistance to at least one antimicrobial agent was detected in 73% of the strains, and one or more resistant strains were recovered from pigs in 93% of the herds. Antimicrobial agent resistance (AR) was more frequent among the most prevalent than it was among the rarer serotypes. Twenty-five multi-AR patterns were found. Resistance to three or more families of antimicrobial agents was found in 75% of AR strains. The finding that many of the herds yielded isolates of several multi-AR patterns indicates that Salmonella infections were acquired from multiple sources. High prevalence of Salmonella in herds was associated with lack of rodent control programs, herds from farms with only finishing pigs, herds managed by more than one full-time worker, herds for which the source of drinking water was not a city supply, and relatively long fattening times.     

Atmospheric dry deposition of persistent organic pollutants to the Atlantic and inferences for the global oceans

Atmospheric deposition to the oceans is a key process affecting the global dynamics and sinks of persistent organic pollutants (POPs). A new methodology that combines aerosol remote sensing measurements with measured POP aerosol-phase concentrations is presented to derive dry particulate depositional fluxes of POPs to the oceans. These fluxes are compared with those due to diffusive air-water exchange. For all polychlorinated biphenyl (PCB) congeners and lower chlorinated dibenzo-p-dioxins and furans (PCDD/Fs), air-water exchange dominates the dry deposition mechanism. However, this tendency reverses in some areas, such as in marine aerosol influenced areas and dust outflow regions, consistent with the important variability encountered for the depositional fluxes. Seasonal variability is mainly found in mid-high latitudes, due to the important influence of wind speed enhancing dry deposition fluxes and temperature as a driver of the gas-particle partitioning of POPs. The average dry aerosol deposition flux of sigmaPCBs and sigmaPCDD/Fs to the Atlantic Ocean is calculated to be in the order of 66 ng m(-2) yr(-1) and 9 ng m(-2)yr(-1) respectively. The total dry aerosol deposition of sigmaPCBs and sigmaPCDD/Fs to the Atlantic Ocean is estimated to be 2200 kg yr(-1) and 500 kg yr(-1), respectively, while the net air-water exchange is higher, 22000 kg sigmaPCBs yr(-1) for PCBs and 1300 kg sigmaPCDD/Fs yr(-1). Furthermore, it is suggested that marine aerosol plays an important role in scavenging atmospheric contaminants.     

A heuristic search algorithm with modifiable estimate

This paper describes an improved version of two previously published algorithms in the area: $\text{A1}$ and B. The new approach is based on considering the estimate ?(n) on node n as a variable rather than as a constant. The new algorithm thus improves the estimate as it goes on, avoiding some useless node expansions. It is proved to never expand more nodes than B or $\text{A1}$ and to expand a much smaller number of them in some cases.Another result of the paper is a proof that no overall optimal algorithm exists if the cost of an algorithm is measured by the total number of node expansions.     

Treatment of dark fermentative H2 production effluents by microbial fuel cells: A tutorial review on promising operational strategies and practices

Deriving biohydrogen from dark fermentation is a practically suitable pathway for scaling-up and envisaged mass production. However, a common issue with these systems is the incomplete conversion of feedstock as a result of which, a process effluent with notable organic strength is left behind. The main components of dark fermentation effluents are volatile fatty acids that can be utilized by integrated applications involving bioelectrochemical systems, particularly microbial fuel cells (MFCs) to generate electrical energy. In this work, MFCs deployed to treat dark fermentative H₂ production effluents are assessed to take a look into the current standing of this specific research area and address what MFC design and operating features (reactor configuration, mode of operation, anode surface and reactor size) seem favorable towards improved working efficiency (e.g. power density, Coulombic efficiency, COD removal). Furthermore, promising technological implementations are outlined and suggestions, conclusions for future studies for this field are given.     

Antimicrobial functionalization of Ca alginate-coconut oil latent heat storing microcapsules by Ag nanoparticles

Latent heat storage by phase change materials (PCM) is a promising way of thermal energy storage for equilibrating the daily fluctuation of temperature in office- and home buildings. Bio-originated compounds have got great importance to evade further plastic contamination all over the world. Durability of biodegradable natural materials by means of environmentally friendly agents is an exciting challenge. In this study Ca alginate-coconut oil eco-friendly core-shell PCM microcapsules were functionalized with Ag nanoparticles, following their synthesis using harmless reducing agents. Throughout the preparation of the PCM microcapsules by repeated interfacial coacervation/crosslinking procedure, the Ag nanoparticles were homogeneously dispersed in the Ca alginate shell. High coconut oil content was achieved in the Ag nanoparticle-loaded microcapsules, which was not influenced by the Ag nanoparticle content. The high PCM content resulted in correspondingly high latent heat storing capability. The freezing and melting heat storing capacities were in the range of 83.6 and 85.6 J/g, as well as 89.7 to 92.6 J/g, respectively, matching to the extremely high PCM content in the range of 82.7% to 84.8% (m/m). Leaking of the heat storing microcapsules was not observed after 200 heating-cooling cycles. The Ag nanoparticle content did not influence the PCM ratio of the microcapsules, although as expected their antimicrobial potential was significantly enhanced by it. The highest Ag nanoparticle loading, that was 1.3% (m/m) related to the total mass of microcapsules, exerted excellent antibacterial and antifungal impact.