Patterning of mutually interacting bacterial bodies: close contacts and airborne signals

<p>Abstract</p> <p>Background</p> <p>Bacterial bodies (colonies) can develop complex patterns of color and structure. These patterns may arise as a result of both colony-autonomous developmental and regulatory processes (self-patterning) and environmental influences, including those generated by neighbor bodies. We have studied the interplay of intra-colony signaling (self-patterning) and inter-colony influences in related clones of <it>Serratia rubidaea </it>grown on rich media.</p> <p>Results</p> <p>Colonies are shaped by both autonomous patterning and by signals generated by co-habitants of the morphogenetic space, mediating both internal shaping of the body, and communication between bodies sharing the same living space. The result of development is affected by the overall distribution of neighbors in the dish. The neighbors' presence is communicated via at least two putative signals, while additional signals may be involved in generating some unusual patterns observed upon encounters of different clones. A formal model accounting for some aspects of colony morphogenesis and inter-colony interactions is proposed.</p> <p>Conclusions</p> <p>The complex patterns of color and texture observed in <it>Serratia rubidaea </it>colonies may be based on at least two signals produced by cells, one of them diffusing through the substrate (agar) and the other carried by a volatile compound and absorbed into the substrate. Differences between clones with regard to the interpretation of signals may result from different sensitivity to signal threshold(s).</p

Adaptation of free and immobilized brewery years during attenuation if highly concentrated hopped worts.

The attenuation of highly concentrated hopped worts by means of non-stressed or stress-adapted yeast was compared in this work. As the yeast adaptation is very dependent on the genetic base of the yeast strain and its physiological state, the results of the study can be considered as a representation of possible behavior of solely brewery yeast. The use of non-stressed cells for attenuation of highly concentrated hopped worts led to the accumulation of trehalose in cells during the fermentation process. If, however, some cells, previously exposed to higher stress, were used for the wort attenuation, the intracellular trehalose dropped. These conclusion were confirmed both for free and immobilized yeast. During the attenuation of highly concentrated hopped wort the free and immobilized yeast, previously exposed to stress achieved higher speed of ethanol formation than the non-stressed yeast. In mutual comparison of beers no marked difference was observed in the process of fermentation of 12 or 24 % hopped worts by means of either stressed or non stressed yeast resulted, notwithstanding, in a considerably shorted time necessary for the fermentation of a 24 % hopped wort.(In Czech, English summary only

Exploitation possibilities of glucose-maltose syrups in substitution of wort extract.

The work compares the glucose-maltose syrups and saccharose from the point of view of their utilization as replacements of part of wort extract in production of the 12= beer. The attenuation degree as well as the amount of produced ethanol in beer increase proportionally to the percentage of the substitute while the quality of nitrogenous matters and polyphenols, together with the temperature and colour of beer fall. Those changes became less evident in the mentioned syrups then in saccharose. The best result was achieved with the preparator Fermentose 352. When the extract was replaced by the mentioned preparator instead of by saccharose, the amount of diacetyl in hopped wort did not raise and decrease of amount of higher alcohols and of esters appeared only after the extract substitution surpassed 30 %.The work compares the glucose-maltose syrups and saccharose from the point of view of their utilization as replacements of part of wort extract in production of the 12= beer. The attenuation degree as well as the amount of produced ethanol in beer increase proportionally to the percentage of the substitute while the quality of nitrogenous matters and polyphenols, together with the temperature and colour of beer fall. Those changes became less evident in the mentioned syrups then in saccharose. The best result was achieved with the preparator Fermentose 352. When the extract was replaced by the mentioned preparator instead of by saccharose, the amount of diacetyl in hopped wort did not raise and decrease of amount of higher alcohols and of esters appeared only after the extract substitution surpassed 30 %

Developmental plasticity of bacterial colonies and consortia in germ-free and gnotobiotic settings

<p>Abstract</p> <p>Background</p> <p>Bacteria grown on semi-solid media can build two types of multicellular structures, depending on the circumstances. Bodies (colonies) arise when a single clone is grown axenically (germ-free), whereas multispecies chimeric consortia contain monoclonal microcolonies of participants. Growth of an axenic colony, mutual interactions of colonies, and negotiation of the morphospace in consortial ecosystems are results of intricate regulatory and metabolic networks. Multicellular structures developed by <it>Serratia</it> sp. are characteristically shaped and colored, forming patterns that reflect their growth conditions (in particular medium composition and the presence of other bacteria).</p> <p>Results</p> <p>Building on our previous work, we developed a model system for studying ontogeny of multicellular bacterial structures formed by five <it>Serratia</it> sp. morphotypes of two species grown in either "germ-free" or "gnotobiotic" settings (i.e. in the presence of bacteria of other conspecific morphotype, other <it>Serratia</it> species, or <it>E. coli</it>). Monoclonal bodies show regular and reproducible macroscopic appearance of the colony, as well as microscopic pattern of its growing margin. Standard development can be modified in a characteristic and reproducible manner in close vicinity of other bacterial structures (or in the presence of their products). Encounters of colonies with neighbors of a different morphotype or species reveal relationships of dominance, cooperation, or submission; multiple interactions can be summarized in "rock – paper – scissors" network of interrelationships. Chimerical (mixed) plantings consisting of two morphotypes usually produced a “consortium” whose structure is consistent with the model derived from interaction patterns observed in colonies.</p> <p>Conclusions</p> <p>Our results suggest that development of a bacterial colony can be considered analogous to embryogenesis in animals, plants, or fungi: to proceed, early stages require thorough insulation from the rest of the biosphere. Only later, the newly developing body gets connected to the ecological interactions in the biosphere. Mixed “anlagen” cannot accomplish the first, germ-free phase of development; hence, they will result in the consortium of small colonies. To map early development and subsequent interactions with the rest of the biospheric web, simplified gnotobiotic systems described here may turn to be of general use, complementing similar studies on developing multicellular eukaryots under germ-free or gnotobiotic conditions.</p

Grapevine European catalogue: towards a comprehensive list

The present attempt to establish a comprehensive and harmonized list of grapevine varieties authorized in Europe represents the contribution of the group of experts within the project GrapeGen06. In no case is this work intended to substitute for administrative initiatives in progress and has the sole aim to make available to professionals a usable document. To the involved people, the list presented here is a tool that will facilitate the implementation of the European regulations on grapevine. It also offers a panorama of the European grapevine genetic potential, thus enabling to specify whose responsibilities are involved and how much efforts should be produced to plan a sound genetic resources protection and further breeding. In this respect it is worth to underline the fact that over half of the varieties are registered in only one Member State. This opens new perspectives emphasizing the importance of European inter-institute cooperation for sharing conservation and breeding responsibilities. Considering the natural evolution of the national catalogues of grape varieties in each Member State and the progress in grape variety identification, it would be necessary to consider an annual update of this European harmonized catalogue