Utjecaj DL-jabučne kiseline na metabolizam L-jabučne kiseline tijekom alkoholnog vrenja

Insufficient wine acidity can affect wine quality and stability. To overcome this problem, DL-malic acid can be added to the grape juice prior to fermentation. We have investigated the effect of DL-malic acid on wine fermentations and its influence on the final concentration of L-malic acid, naturally present in grape juice. To this end yeast strains that metabolise L-malic acid in different ways were tested and compared; namely, Schizosaccharomyces pombe (efficient L-malic acid degrader), Saccharomyces cerevisiae (non-degrader), hybrid strain S. cerevisiae x S. uvarum (intermediate degrader) and Saccharomyces uvarum (promoting L-malic acid synthesis). In all cases, D-malic acid passively entered the yeast cells and did not undergo malo-alcoholic fermentation. However, its presence in the juice, as a component of the mixture of D- and L- malic acid (DL-malic acid), reduced the amount of L-malic acid that can be degraded or synthesised by yeasts during malo-alcoholic fermentation.Nedovoljna kiselost vina može utjecati na njegovu kakvoću i stabilnost. Da bi se riješio taj problem, može se moštu prije vrenja dodati DL-jabučna kiselina. Ispitan je utjecaj DL-jabučne kiseline na fermentaciju vina i njezin utjecaj na konačnu koncentraciju L jabučne kiseline koja se nalazi u moštu. Stoga su ispitani i uspoređeni sojevi kvasca koji metaboliziraju L-jabučnu kiselinu, i to Schizosaccharomyces pombe (djelotvoran razgrađivač L-jabučne kiseline), S. cerevisiae (ne razgrađuje), hibridni soj S. cerevisiae x S. uvarum (djelomično razgrađuje) i S. uvarum (promotor sinteze jabučne kiseline). U svim slučajevima D-jabučna kiselina pasivno ulazi u stanice kvasca i ne provodi jabučno-alkoholno vrenje. Međutim, njezina prisutnost u grožđanom soku, kao dio smjese D- i L jabučne kiseline (DL-jabučna kiselina) snizuje količinu jabučne kiseline koja se može razgraditi ili sintetizirati s kvascima tijekom jabučno-alkoholnog vrenja

Moloney murine leukemia virus decay mediated by retroviral reverse transcriptase degradation of genomic RNA

AbstractRetroviral vectors are powerful tools for the introduction of transgenes into mammalian cells and for long-term gene expression. However, their application is often limited by a rapid loss of bioactivity: retroviruses spontaneously loose activity at 37 °C, with a half-life of 4 to 9 h depending on the retrovirus type. We sought to determine which components of the retrovirus are responsible for this loss in bioactivity and to obtain a quantitative characterization of their stability. To this end, we focused on RNA and viral proteins, two major components that we hypothesized may undergo degradation and negatively influence viral infectivity. Reverse transcription PCR (RT-PCR) targeting RNA encoding portions of the viral genome clearly demonstrated time-dependent degradation of RNA which correlated with the loss in viral bioactivity. Circular dichroism spectroscopy, SDS-PAGE and two-dimensional SDS-PAGE analyses of viral proteins did not show any change in secondary structure or evidence of proteolysis. The mechanism underlying the degradation of viral RNA was investigated by site-directed mutagenesis of proteins encoded by the viral genome. Reverse transcriptase and protease mutants exhibited enhanced RNA stability in comparison to wild type recombinant virus, suggesting that the degradation of RNA, and the corresponding virus loss of activity, is mediated by the reverse transcriptase enzyme

Utjecaj autolize bakterija mliječno-kiselog vrenja na senzorske značajke fermentiranih namirnica

Lactic acid bacteria autolysis is due to intracellular hydrolytic enzymes that act on specific parts of the cell wall causing the release of biologically active compounds, in particular enzymes, to the medium. Consequently, the role of lactic acid bacteria in the transformation of foodstuffs does not involve merely the fermentation stage but also the later maturation and aging stage thanks to the compounds released to the medium that combine in order to change the sensorial profile of the product. This phenomenon is particularly important for cheese types subjected to very long aging, for salami ripening and for red aged wines.Autoliza bakterija mliječno-kiselog vrenja nastaje djelovanjem intracelularnih hidrolitičkih enzima koji u reakciji sa specifičnim dijelovima staničnog zida uzrokuju izlazak biološki aktivnih spojeva, osobito enzima, u podlogu. Stoga utjecaj tih bakterija na promjene u namirnicama nije ograničen samo na fermentaciju već i na vrijeme zrenja i starenja zbog spojeva koji su iz stanica ušli u medij, što dovodi do promjena senzorskih značajki proizvoda. Taj je proces posebno važan za vrste sira koje dugo sazrijevaju, za zrenje salame i za proizvodnju odležanih crvenih vina

Software engineering for self-adaptive systems:research challenges in the provision of assurances

The important concern for modern software systems is to become more cost-effective, while being versatile, flexible, resilient, dependable, energy-efficient, customisable, configurable and self-optimising when reacting to run-time changes that may occur within the system itself, its environment or requirements. One of the most promising approaches to achieving such properties is to equip software systems with self-managing capabilities using self-adaptation mechanisms. Despite recent advances in this area, one key aspect of self-adaptive systems that remains to be tackled in depth is the provision of assurances, i.e., the collection, analysis and synthesis of evidence that the system satisfies its stated functional and non-functional requirements during its operation in the presence of self-adaptation. The provision of assurances for self-adaptive systems is challenging since run-time changes introduce a high degree of uncertainty. This paper on research challenges complements previous roadmap papers on software engineering for self-adaptive systems covering a different set of topics, which are related to assurances, namely, perpetual assurances, composition and decomposition of assurances, and assurances obtained from control theory. This research challenges paper is one of the many results of the Dagstuhl Seminar 13511 on Software Engineering for Self-Adaptive Systems: Assurances which took place in December 2013

Profile based comparative analysis for AOSE methodologies evaluation

This study focuses on the analysis and evaluation of agent-oriented methodologies. Different studies have been proposed for the evaluation of agent-oriented methodologies adopting specifics types of evaluation and criteria. The present work proposes to adopt the Profile Analysis technique for comparing evaluations carried out by different authors (perhaps using different evaluation frameworks) with the aim of improving the acceptability of agent-oriented methodologies evaluation in the agent community. To exemplify the proposal, we present the application of the Profile Analysis technique on a case study

Multi-Agent Abstractions and Organizations and the i* Framework

i* is one of the more promising goal-oriented modeling framework tocapture and model multi agent systems (MAS) requirements. Moreover, i* has beenincorporated as the foundation for one of the more important AOSE methodologies,that is, Tropos. Our research interests related with i* cover two mainly directions. Thefirst, is to compare i* with other methods, techniques and notations for capturing andmodeling MAS abstractions. The second is related to the computational organizationtheory to model the organizational perspective of the MAS. Specifically, we areanalyzing the critical issue of coping with adaptive changes of MAS organizationswhenever circumstances claim for changes in the very MAS structure. Then, we aresurveying different relevant AOSE methodologies, Tropos (and therefore i*) amongothers, to discuss their suitability in dealing with adaptation in MAS organizations

GAIA4E: A Tool Supporting the Design of MAS Using Gaia

Different efforts have been devoted to improve the original version of Gaia methodology. The more relevantis the official extension of Gaia, exploiting the organizational abstractions to provide clear guidelines for theanalysis and design of complex and open multiagent systems. However, now a day a successful designmethodology should include some other strategic factors like the support of a specific CASE tool tosimplify the work of the designer. Such a tool supporting the Gaia design process may facilitate theadoption of the methodology in the industrial arena. The present study introduces Gaia4E, a plug-in for theECLIPSE environment which covers all the phases of Gaia allowing agent engineers to produce anddocument the corresponding models

Process models for agent-based development

A great deal of research in the area of agent-oriented software engineering (AOSE) focuses on proposing methodologies for agent systems, i.e., on identifying the guidelines to drive the various phases of agent-based software development and the abstractions to be exploited in these phases. However, very little attention has been paid so far to the engineering process subjacent to the development activity, disciplining the execution of the different phases involved in the software development. In this paper, we focus on process models for software development and put these in relation with current researches in AOSE. First, we introduce the key concepts and issues related to software processes and present the various software process models currently adopted in mainstream software engineering. Then, we survey the characteristics of a number of agent-oriented methodologies, as they pertain to software processes. In particular, for each methodology, we analyze which software process model it (often implicitly) underlies and which phases of the process are covered by it, thus enabling us to identify some key limitations of currently methodology-centered researches. On this basis, we eventually identify and analyze several open issues in the area of software process models for agent-based development, calling for further researches and experiences

Utjecaj autolize bakterija mliječno-kiselog vrenja na senzorske značajke fermentiranih namirnica

Lactic acid bacteria autolysis is due to intracellular hydrolytic enzymes that act on specific parts of the cell wall causing the release of biologically active compounds, in particular enzymes, to the medium. Consequently, the role of lactic acid bacteria in the transformation of foodstuffs does not involve merely the fermentation stage but also the later maturation and aging stage thanks to the compounds released to the medium that combine in order to change the sensorial profile of the product. This phenomenon is particularly important for cheese types subjected to very long aging, for salami ripening and for red aged wines.Autoliza bakterija mliječno-kiselog vrenja nastaje djelovanjem intracelularnih hidrolitičkih enzima koji u reakciji sa specifičnim dijelovima staničnog zida uzrokuju izlazak biološki aktivnih spojeva, osobito enzima, u podlogu. Stoga utjecaj tih bakterija na promjene u namirnicama nije ograničen samo na fermentaciju već i na vrijeme zrenja i starenja zbog spojeva koji su iz stanica ušli u medij, što dovodi do promjena senzorskih značajki proizvoda. Taj je proces posebno važan za vrste sira koje dugo sazrijevaju, za zrenje salame i za proizvodnju odležanih crvenih vina

Effects of Lactic Acid Bacteria Autolysis on Sensorial Characteristics of Fermented Foods

Lactic acid bacteria autolysis is due to intracellular hydrolytic enzymes that act on specific parts of the cell wall causing the release of biologically active compounds, in particular enzymes, to the medium. Consequently, the role of lactic acid bacteria in the transformation of foodstuffs does not involve merely the fermentation stage but also the later maturation and aging stage thanks to the compounds released to the medium that combine in order to change the sensorial profile of the product. This phenomenon is particularly important for cheese types subjected to very long aging, for salami ripening and for red aged wines