Serratia marcescens forms different colony patterns under distinct conditions. One of them is the concentric fountain-shaped pattern with pigmented center followed by unpigmented ring and pigmented rim. In this work, we study this pattern formation by construction of the mathematical model able to display this pattern based on putative metabolical traits, supported by series of experiments and by references. A pattern formation of such colony type depends on the disposition of glucose and amino acids, and is accompanied by a pH change in the agar medium. In this paper, we confirm that a metabolic activity of growing colony alters its environment which subsequently changes the colony formation. Presented model corresponds well with the real colony behaviour.
We extend the palette of possible colonies models of two different clones of Serratia rubidaea. Our model fits the real morphology of the colonies. We also present that the colony growth leads to a change in the ratio of the fitness which propose to be caused by the production of some signal. This signal influences the behavior of the clones and leads to the prolonged diversity maintenance. The explanation of the diversity maintenance of the mixed concurrent population in one niche is the current studied problem in the ecology and evolution.
Spontaneous variation in appearance was studied in bacterial colonies of Serratia marcescens F morphotype(1): (i) A defined array of non-heritable phenotype variations does appear repeatedly; (ii) The presence of colonies of different bacterial species will narrow the variability toward the typical F appearance, as if such an added environmental factor curtailed the capacity of colony morphospace; (iii) Similarly the morphospace becomes reduced by random mutations leading to new, heritable morphotypes-at the same time opening a new array of variations typical for the mutant but not accessible directly from the original F morphospace. Results are discussed in context with biphasic model of early morphogenesis applicable to all multicellular bodies.
- Publikační typ
- časopisecké články MeSH
Current knowledge of the genetic mechanisms underlying the inheritance of photosynthetic activity in forest trees is generally limited, yet it is essential both for various practical forestry purposes and for better understanding of broader evolutionary mechanisms. In this study, we investigated genetic variation underlying selected chlorophyll a fluorescence (ChlF) parameters in structured populations of Scots pine (Pinus sylvestris L.) grown on two sites under non-stress conditions. These parameters were derived from the OJIP part of the ChlF kinetics curve and characterize individual parts of primary photosynthetic processes associated, for example, with the exciton trapping by light-harvesting antennae, energy utilization in photosystem II (PSII) reaction centers (RCs) and its transfer further down the photosynthetic electron-transport chain. An additive relationship matrix was estimated based on pedigree reconstruction, utilizing a set of highly polymorphic single sequence repeat markers. Variance decomposition was conducted using the animal genetic evaluation mixed-linear model. The majority of ChlF parameters in the analyzed pine populations showed significant additive genetic variation. Statistically significant heritability estimates were obtained for most ChlF indices, with the exception of DI0/RC, φD0 and φP0 (Fv/Fm) parameters. Estimated heritabilities varied around the value of 0.15 with the maximal value of 0.23 in the ET0/RC parameter, which indicates electron-transport flux from QA to QB per PSII RC. No significant correlation was found between these indices and selected growth traits. Moreover, no genotype × environment interaction (G × E) was detected, i.e., no differences in genotypes' performance between sites. The absence of significant G × E in our study is interesting, given the relatively low heritability found for the majority of parameters analyzed. Therefore, we infer that polygenic variability of these indices is selectively neutral.
- MeSH
- borovice lesní genetika fyziologie MeSH
- chlorofyl fyziologie MeSH
- fluorescence MeSH
- fotosyntetické reakční centrum - proteinové komplexy fyziologie MeSH
- fotosyntéza genetika MeSH
- fotosystém II - proteinový komplex fyziologie MeSH
- genetická variace * MeSH
- genotyp * MeSH
- kvantitativní znak dědičný * MeSH
- lesy MeSH
- rostlinné geny MeSH
- stromy genetika fyziologie MeSH
- světlo MeSH
- transport elektronů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Volatiles produced by bacterial cultures are known to induce regulatory and metabolic alterations in nearby con-specific or heterospecific bacteria, resulting in phenotypic changes including acquisition of antibiotic resistance. We observed unhindered growth of ampicillin-sensitive Serratia rubidaea and S. marcescens on ampicillin-containing media, when exposed to volatiles produced by dense bacterial growth. However, this phenomenon appeared to result from pH increase in the medium caused by bacterial volatiles rather than alterations in the properties of the bacterial cultures, as alkalization of ampicillin-containing culture media to pH 8.5 by ammonia or Tris exhibited the same effects, while pretreatment of bacterial cultures under the same conditions prior to antibiotic exposure did not increase ampicillin resistance. Ampicillin was readily inactivated at pH 8.5, suggesting that observed bacterial growth results from metabolic alteration of the medium, rather than an active change in the target bacterial population (i.e. induction of resistance or tolerance). However, even such seemingly simple mechanism may provide a biologically meaningful basis for protection against antibiotics in microbial communities growing on semi-solid media.
- MeSH
- amoniak metabolismus MeSH
- ampicilin chemie farmakologie MeSH
- antibakteriální látky chemie farmakologie MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média chemie metabolismus MeSH
- mikrobiální testy citlivosti MeSH
- rezistence na ampicilin MeSH
- Serratia účinky léků růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
