Vizsgálatok az élesztők tárolásával kapcsolatban II. : az élesztőtej tárolása

Die Haltbarkeit von Hefemilch wird weder durch die Hefekonzentration, noch durch einer unter 2% liegenden Na Cl-Konzentration beeinflusst. Bei den verschiedenen Proben erwies sich die Menge der Stoffe von verschiedenem Stickstoffgehalt, diejenige anderer Stoffe, sowie die Aufgangsfähigkeit zu identischem Zeitpunkte identisch. Mit dem Ansteigen der Temperatur nimmt die Menge der ausgeschiedenen Stoffe rapide zu die Fähigkeit jedoch im Laufe der Lagerung rapide ab. Bei 5° C gelagerter Hefemilch kann man einzig und allein in der Atmungsfähigkeit einen Rückgang beobachten, während der ersten 2 Tage-, die Gärungsfähigkeit bleibt unverändert. Es ist nicht gelungen ausgeschiedene Stoffwechselprodukte nachzuweisen. Bei 253 C vermindert sich sowie die Atmungs- als auch die Gärungsfähigkeit der Hefemilch nahezu auf die Hälfte, bei 50° C konnte man bereits nach eintägiger Lagerung weder Atmungsnoch Gärungsaktivität nachweisen. The storability of yeast milk proved to be not affected by the concentration of yeast and by concentrations of NaCl below 2%, either. In the case of various samples, the quantities of secreted nitrogenous and other metabolites, further the raising powers proved to be identical at the same date. On raising temperature, the quantity of secreted metabolites quickly increased while the raising power abruptly diminished on storage. On storing yeast milk at 5°, in the first two days of storage only the respiration decreased to a slight extent while the raising power remained unchanged. Secretion of metabolites could not be detected. During storage for four days at 25°, both the respiration and the raising power of yeast milk decreased by almost 50%, while on storing one day at 50°, no respiratory or raising activity could be observed at all. La conservation du Iáit de levure n’est pas influencée ni par la concentration en levure ni par une teneur en NaCl inférieure ä 2%. Dans le cas des divers échantillons la quantité des matiéres azotées et des autres corps secrétés, ainsi que la puissance de fermentation se sont montrées identiques au mérne moment. Avec l’élévation de la temperature la quantité des matiéres secrétées visit rapidement, tandis que le pouvoir de fermentation decroit trés vite au cours du stockage. Dans le Iáit de levure conservé a 5° C l’on ne peut observer qu’ une faible diminution de la réspiration pendant les deux premiers jours, la pouvoir de fermentation ne change pas. L’on n’a pás réussi á déceler des produits métaboliques secrétés. A 25° C le pouvoir respiratoire et de fermentation du Iáit de levure diminue presque de moitie pendant quatre jours. A 50° С Гоп n’a pás pu déceler unes act vité respiratrice et fermentatrice déja aprés un stockage de 1 jour

Vizsgálatok az élesztők tárolásával kapcsolatban I. : a gyártás különböző fázisaiból származó élesztők tárolhatósága

Parallel mit der Zunahme der Lüftung sinkt der Gesamtstickstoffgehalt der Hefe, die Haltbarkeit jedoch nimmt in hohem Masse zu. Die Triebfähigkeit der am wenigsten gelüfteten Mutterhefe III. ist am grössten, diese aber nimmt bei 25 C° in Milchform gelagert schnell ab, und am fünften Tage ist schon überhaupt kein Auftrieb wahrnehmbar. Das geschnittene Hefegut wirkt am Anfang wesentlich schlechter, verliert aber von seiner Aktivität selbst am fünften Tage kaum. Die intermediären Phasen weisen einen stufenweisen Übergang auf. Zwischen dem Absinken der Triebfähigkeit und der in den extracellularen Raum ausgeschiedenen Menge stickstoffhaltiger Stoffe war ein ausgesprochener Zusammenhang feststellbar. On increasing the extent of aeration, the total nitrogen content of yeast proved to diminish while its storability markedly improved. Mother yeast III which was aerated to the smallest extent disclosed the highest raising power. However, on keeping the yeast at 25° C in form of a milky suspension, this power rapidly decreased, and it was incapable of raising on the fifth day of storage. The blended commercial yeast showed at the beginning a markedly poorer raising power which however hardly lost anything of this initial power even on the fifth day on storage. The intermediate phases disclosed a gradual transition. A definite correlation was found between the extent of decrease in raising power and the quantity of nitrogenous substances excreted into the extracellular space

Evidence of spreading vasodilation in the human gingiva evoked by nitric oxide

Spreading vasodilation is an important means of increasing local blood flow effectively during increased metabolic demands or in case of vascular injury. Our aim was to develop a technique proving the presence of spreading vasodilation in the human keratinized gingiva.Local vasodilation was evoked by the application of nitric oxide (NO) donor nitroglycerin into a well, fixed 2 mm above the marginal gingiva, in 20 subjects with healthy periodontal tissue. Either 1 or 8 mg/mL nitroglycerin solutions were dropped into the test well at the upper right second incisor, and saline was applied into the control well at the upper left first incisor. The gingival blood flow (GBF) was recorded for 15 minutes by a laser speckle contrast imager below the well and in the surrounding area in the mesial, distal, apical and coronal directions. Gingival thickness was measured by an ultrasonic biometer.Peak GBF increase was similar after 1 mg/mL and after 8 mg/mL nitroglycerin application in the well (51% ± 12% vs 42% ± 8%) and in the apical region (33 ± 9% vs 55% ± 13%). While the lower dose of nitroglycerin increased GBF only in the apical region around the well, the higher dose induced significant elevations in all surrounding regions, with apical prominence. Hyperaemia lasted 10-14 minutes in the low-dose group whereas it extended beyond the observation period in the high-dose group. Neither the baseline nor the NO-induced peak GBF were correlated with gingival thickness.The role of the direct effect of NO in the regulation of perfusion was demonstrated in the human gingiva as well as the propagation of local vasodilation to distant, especially apical areas, probably by the mechanism of flow-mediated dilation. This mechanism may have a clinical importance for flap survival or wound healing

Selfishness versus functional cooperation in a stochastic protocell model

How to design an "evolvable" artificial system capable to increase in complexity? Although Darwin's theory of evolution by natural selection obviously offers a firm foundation, little hope of success seems to be expected from the explanatory adequacy of modern evolutionary theory, which does a good job at explaining what has already happened but remains practically helpless at predicting what will occur. However, the study of the major transitions in evolution clearly suggests that increases in complexity have occurred on those occasions when the conflicting interests between competing individuals were partly subjugated. This immediately raises the issue about "levels of selection" in evolutionary biology, and the idea that multi-level selection scenarios are required for complexity to emerge. After analyzing the dynamical behaviour of competing replicators within compartments, we show here that a proliferation of differentiated catalysts and/or improvement of catalytic efficiency of ribozymes can potentially evolve in properly designed artificial cells. Experimental evolution in these systems will likely stand as beautiful examples of artificial adaptive systems, and will provide new insights to understand possible evolutionary paths to the evolution of metabolic complexity

Vizsgálatok az élesztők tárolásával kapcsolatban III. : sajtolt és szárított élesztő csomagolása és tárolása

Bei Erhöhung der Salzkonzentration von Hefemilch nimmt der Trockensubstanzgehalt der aus ihr bereiteten Hefe indentischer Konsistenz zu. Die unter betrieblichen Verhältnissen verwendete Salzkonzentration beeinflusst die Lagerungsfähigkeit der Hefe nicht. Die gepresste Backhefe weist bei einer Lagerung in 50-100 g Einheiten an luftigem Orte einen grossen Gewichstverlust auf, wenn sie in wasserdampfdurchlässige Folien verpackt wird. Der Gewichtsverlust von Hefen, in wasserunduchlässigen Folien ist minimal. Die Triebfähigkeit hängt von der Menge der anwesenden Hefe-Trockensubstanz ab, der Wasserverlust bedeutet keine Verringerung der Gesamt-Triebfähigkeit des Hefepaketes. Verwendung von undurchlässigen Folien fördert die Weichwerdung der Hefen und die Verminderung der Triebfähigkeit. Die Triebfähigkeit der getrockneten Backhefe erwies sich unabhängig davon, ob die Lagerung in einer Nitrogen einer Kohlendioxid - oder in Luftathmosphäre stattfand. Die Temperatur spielt bei der Lagerung eine wesentliche Rolle; eine Trockenhefe bei 6 C gelagert verliert 20-22 Wochen lang überhaupt nichts von ihrer Triebfähigkeit, hernach aber erfolgt eine rapide Verminderung der Triebfähigkeit. Text der Abbildungen Abbildung 1. Durchspülung der Ampulle mit inertem Gas. 1. Ampulle 2. Getrocknete Backhefe 3. Ausgezogenes Gfasrohr. Prozentueller Abbildung 2. Gewichtsverlust .100 g-haltiger Hefeblockes in verschiedenes Packmaterial verpackt, während der Lagerung in einem kühlen Raume (14- 18 C) Abbildung 3. Gewichtsverlust von 100 g Hefeblocke in verschiedenartiges Packmaterial verpackt bei einer Lagerung von 35 °C im Thermostat Abbildung 4. Prozentueller Gewichtsverlust von 50 g Hefeblocken im Laufe einer Lagerung an kühlem, luftigem Orte. Die Proben wurden gleichzeitig mit den Proben der Abbildung 5. unter identischen Umständen gelagert Abbildung 5. Prozentueller Gewichtsverlust von 100 g Hefeblocks in einem kühlen, luftigen Orte. Die Proben wurden gleichzeitig mit den Proben der Abbildung 5. unter identischen Umständen gelagert Abbildung 6. Veränderung der Triebfähigkeit von auf Gewichtsverlust korrigierten je 100 g Hefe in verschiedenartige Packmateriale verpackt, im Thermostat bei 35 °C gelagert, im Laufe der Lagerung Abbildung 7. Veränderung der Triebfähigkeit von unter verschiedenen Umständen gelagerter'getrockneter Backhefe im Laufe der Lagerung. 1. Im Thermostat (35 °C) in einer Luftathmosphäre 2. Bei Laboratoriumstemperatur in einer Nitrogengasathmosphäre. 3. Bei Laboratoriumstemperatur in Kohlen-dioxidathmosphäre. 4. Bei Laboratoriumstemperatur in der Luftathmosphäre. 5. Im Kühlschrank (6 °C) in Luftathmosphäre. On increasing the salt content of yeast, also the dry matter content of the yeast of identical consistency obtained from the salted yeast rises. However, the storability of yeast proved to be not affected by the salt’concentrations generally applied under industrial conditions. When 5 0 - 100 g doses of compressed yeast are packed in foils permeable to water vapour, they suffer marked weight losses on storage in aerated rooms, while only minimum weight losses were observed in the case of yeast packed in impermeable foils. The raising power of yeasts depends on the amount of dry matter present, and losses of water are not connected with a decrease of the overall raising power of packed yeasts. The use of impermeable foils promotes the softening of yeasts and the deterioration of their raising power. The raising power of dried baker’s yeast proved to be independent of the fact whether the yeast has been stored in air or in a nitrogen or carbon dioxide atmosphere. The temperature of storage is of great importance, e. g. dry yeast stored at 6 °C did not show any decrease of raising power for 20-22 weeks. However, after this period, a rapid drop of raising power wras experienced

A New Replicator: A theoretical framework for analysing replication

<p>Abstract</p> <p>Background</p> <p>Replicators are the crucial entities in evolution. The notion of a replicator, however, is far less exact than the weight of its importance. Without identifying and classifying multiplying entities exactly, their dynamics cannot be determined appropriately. Therefore, it is importance to decide the nature and characteristics of any multiplying entity, in a detailed and formal way.</p> <p>Results</p> <p>Replication is basically an autocatalytic process which enables us to rest on the notions of formal chemistry. This statement has major implications. Simple autocatalytic cycle intermediates are considered as non-informational replicators. A consequence of which is that any autocatalytically multiplying entity is a replicator, be it simple or overly complex (even nests). A stricter definition refers to entities which can inherit acquired changes (informational replicators). Simple autocatalytic molecules (and nests) are excluded from this group. However, in turn, any entity possessing copiable information is to be named a replicator, even multicellular organisms. In order to deal with the situation, an abstract, formal framework is presented, which allows the proper identification of various types of replicators. This sheds light on the old problem of the units and levels of selection and evolution. A hierarchical classification for the partition of the replicator-continuum is provided where specific replicators are nested within more general ones. The classification should be able to be successfully applied to known replicators and also to future candidates.</p> <p>Conclusion</p> <p>This paper redefines the concept of the replicator from a bottom-up theoretical approach. The formal definition and the abstract models presented can distinguish between among all possible replicator types, based on their quantity of variable and heritable information. This allows for the exact identification of various replicator types and their underlying dynamics. The most important claim is that replication, in general, is basically autocatalysis, with a specific defined environment and selective force. A replicator is not valid unless its working environment, and the selective force to which it is subject, is specified.</p

On RAF Sets and Autocatalytic Cycles in Random Reaction Networks

The emergence of autocatalytic sets of molecules seems to have played an important role in the origin of life context. Although the possibility to reproduce this emergence in laboratory has received considerable attention, this is still far from being achieved. In order to unravel some key properties enabling the emergence of structures potentially able to sustain their own existence and growth, in this work we investigate the probability to observe them in ensembles of random catalytic reaction networks characterized by different structural properties. From the point of view of network topology, an autocatalytic set have been defined either in term of strongly connected components (SCCs) or as reflexively autocatalytic and food-generated sets (RAFs). We observe that the average level of catalysis differently affects the probability to observe a SCC or a RAF, highlighting the existence of a region where the former can be observed, whereas the latter cannot. This parameter also affects the composition of the RAF, which can be further characterized into linear structures, autocatalysis or SCCs. Interestingly, we show that the different network topology (uniform as opposed to power-law catalysis systems) does not have a significantly divergent impact on SCCs and RAFs appearance, whereas the proportion between cleavages and condensations seems instead to play a role. A major factor that limits the probability of RAF appearance and that may explain some of the difficulties encountered in laboratory seems to be the presence of molecules which can accumulate without being substrate or catalyst of any reaction.Comment: pp 113-12