Biochemical aspects of seedcoat colour inheritance in Phaseolus vulgaris L.

The influence was investigated of 2 gene pairs (V-v laeand Sh-sh) and a multiple allelic series of 3 alleles (C r-C-c u) on pigment synthesis in the seedcoat of Phaseolus vulgaris. All 12 homozygous combinations were examined in pure lines. These lines were obtained from F 2 offspring by visual selection. Each type possessed the basis gene P, which did not itself produce any colour but whose presence was needed for the activity of other genes influencing seedcoat colour.As pigments 18 different flavonoid compounds were isolated and 15 of them identified.The gene pair V-v laecontrolled the number of hydroxyl groups in the B ring of the compounds formed. V probably acted on a precursor from which all these compounds were synthetized. The number of hydroxyl groups in the B ring proved to influence the action of other genes, determining the heterocyclic part of structure.The multiple allelic series C r-C-c ucontrolled the formation of anthocyanins or flavonol glycosides. With c unone of these compounds was formed. The role also of C and C rcould be traced. A hypothesis was put forward to explain the phenomena, not previously found in any plant species.Sh controlled the formation of leuco-anthocyanidins and stimulated the production of anthocyanins and flavonol glycosides formed in the presence of C of C r. This was the first investigation in which a single gene had been found responsible for the production of leuco-anthocyanidins

Design Issues for Qualitative Modelling of Biological Cells with Petri Nets

Abstract. Petri nets are a widely used formalism to qualitatively model concurrent systems such as a biological cell. We present techniques for modelling biological processes as Petri nets for further analyses and insilico experiments. Instead of extending the formalism with,,colours ” or rates, as is most often done, we focus on preserving the simplicity of the formalism and developing an execution semantics which resembles biology – we apply a principle of maximal parallelism and introduce the novel concept of bounded execution with overshooting. A number of modelling solutions are demonstrated using the example of the wellstudied C. elegans vulval development process. To date our model is still under development, but first results, based on Monte Carlo simulations, are promising.

Twitch and tetanic tension during culture of mature Xenopus laevis single muscle fibres

Investigation of the mechanisms of muscle adaptation requires independent control of the regulating factors. The aim of the present study was to develop a serum-free medium to culture mature single muscle fibres of Xenopus laevis. As an example, we used the culture system to study adaptation of twitch and tetanic force characteristics, number of sarcomeres in series and fibre cross-section. Fibres dissected from m. iliofibularis (n = 10) were kept in culture at a fibre mean sarcomere length of 2.3 µm in a culture medium without serum. Twitch and tetanic tension were determined daily. Before and after culture the number of sarcomeres was determined by laser diffraction and fibre cross-sectional area (CSA) was determined by microscopy. For five fibres twitch tension increased during culture and tetanic tension was stable for periods varying from 8 to 14 days (‘stable fibres’), after which fibres were removed from culture for analysis. Fibre CSA and the number of sarcomeres in series remained constant during culture. Five other fibres showed a substantial reduction in twitch and tetanic tension within the first five days of culture (‘unstable fibres’). After 7–9 days of culture, three of these fibres died. For two of the unstable fibres, after the substantial force reduction, twitch and tetanic tension increased again. Finally at day 14 and 18 of culture, respectively, the tensions attained values higher than their original values. For stable fibres, twitch contraction time, twitch half-relaxation time and tetanus 10%-relaxation time increased during culture. For unstable fibres these parameters fluctuated. For all fibres the stimulus threshold fluctuated during the first two days, and then remained constant, even for the fibres that were cultured for at least two weeks. It is concluded that the present culture system for mature muscle fibres allows long-term studies within a well-defined medium. Unfortunately, initial tetanic and twitch force are poor predictors of the long-term behaviour of the fibres

Computer modeling of diabetes and Its transparency: a report on the Eighth Mount Hood Challenge

Objectives The Eighth Mount Hood Challenge (held in St. Gallen, Switzerland, in September 2016) evaluated the transparency of model input documentation from two published health economics studies and developed guidelines for improving transparency in the reporting of input data underlying model-based economic analyses in diabetes. Methods Participating modeling groups were asked to reproduce the results of two published studies using the input data described in those articles. Gaps in input data were filled with assumptions reported by the modeling groups. Goodness of fit between the results reported in the target studies and the groups’ replicated outputs was evaluated using the slope of linear regression line and the coefficient of determination (R2). After a general discussion of the results, a diabetes-specific checklist for the transparency of model input was developed. Results Seven groups participated in the transparency challenge. The reporting of key model input parameters in the two studies, including the baseline characteristics of simulated patients, treatment effect and treatment intensification threshold assumptions, treatment effect evolution, prediction of complications and costs data, was inadequately transparent (and often missing altogether). Not surprisingly, goodness of fit was better for the study that reported its input data with more transparency. To improve the transparency in diabetes modeling, the Diabetes Modeling Input Checklist listing the minimal input data required for reproducibility in most diabetes modeling applications was developed. Conclusions Transparency of diabetes model inputs is important to the reproducibility and credibility of simulation results. In the Eighth Mount Hood Challenge, the Diabetes Modeling Input Checklist was developed with the goal of improving the transparency of input data reporting and reproducibility of diabetes simulation model results

Biochemical aspects of seedcoat colour inheritance in Phaseolus vulgaris L.

The influence was investigated of 2 gene pairs (V-v laeand Sh-sh) and a multiple allelic series of 3 alleles (C r-C-c u) on pigment synthesis in the seedcoat of Phaseolus vulgaris. All 12 homozygous combinations were examined in pure lines. These lines were obtained from F 2 offspring by visual selection. Each type possessed the basis gene P, which did not itself produce any colour but whose presence was needed for the activity of other genes influencing seedcoat colour.As pigments 18 different flavonoid compounds were isolated and 15 of them identified.The gene pair V-v laecontrolled the number of hydroxyl groups in the B ring of the compounds formed. V probably acted on a precursor from which all these compounds were synthetized. The number of hydroxyl groups in the B ring proved to influence the action of other genes, determining the heterocyclic part of structure.The multiple allelic series C r-C-c ucontrolled the formation of anthocyanins or flavonol glycosides. With c unone of these compounds was formed. The role also of C and C rcould be traced. A hypothesis was put forward to explain the phenomena, not previously found in any plant species.Sh controlled the formation of leuco-anthocyanidins and stimulated the production of anthocyanins and flavonol glycosides formed in the presence of C of C r. This was the first investigation in which a single gene had been found responsible for the production of leuco-anthocyanidins