Many microorganisms face a fundamental trade-off between reproduction and survival: Rapid growth boosts population size but makes microorganisms sensitive to external stressors. Here, we show that starved bacteria encountering new resources can break this trade-off by evolving phenotypic heterogeneity in lag time. We quantify the distribution of single-cell lag times of populations of starved Escherichia coli and show that population growth after starvation is primarily determined by the cells with shortest lag due to the exponential nature of bacterial population dynamics. As a consequence, cells with long lag times have no substantial effect on population growth resumption. However, we observe that these cells provide tolerance to stressors such as antibiotics. This allows an isogenic population to break the trade-off between reproduction and survival. We support this argument with an evolutionary model which shows that bacteria evolve wide lag time distributions when both rapid growth resumption and survival under stressful conditions are under selection. Our results can explain the prevalence of antibiotic tolerance by lag and demonstrate that the benefits of phenotypic heterogeneity in fluctuating environments are particularly high when minorities with extreme phenotypes dominate population dynamics.

Recent progress in cassava transformation has allowed the robust production of transgenic cassava even under suboptimal plant tissue culture conditions. The transformation protocol has so far been used mostly for the cassava model cultivar 60444 because of its good regeneration capacity of embryogenic tissues. However, for deployment and adoption of transgenic cassava in the field it is important to develop robust transformation methods for farmer- and industry-preferred landraces and cultivars. Because dynamics of multiplication and regeneration of embryogenic tissues differ between cassava genotypes, it was necessary to adapt the efficient cv. 60444 transformation protocol to genotypes that are more recalcitrant to transformation. Here we demonstrate that an improved cassava transformation protocol for cv. 60444 could be successfully modified for production of transgenic farmer-preferred cassava landraces. The modified transformation method reports on procedures for optimization and is likely transferable to other cassava genotypes reportedly recalcitrant to transformation provided production of high quality FEC. Because the three farmer-preferred cassava landraces selected in this study have been identified as resistant or tolerant to cassava mosaic disease (CMD), the adapted protocol will be essential to mobilize improved traits into cassava genotypes suitable for regions where CMD limits production.

Background Non-pharmacological interventions are recommended to manage challenging behaviours among cognitively impaired older adults, however few studies have enrolled patients in acute care. This study aimed to determine the feasibility of implementing non-pharmacological interventions to manage behaviours in hospitalized older adults. Method A self-identity approach was used to identify potentially engaging activities for 13 older medically ill adults admitted to acute hospital; these activities were trialed for a two-week period. Data were collected on frequency of intervention administration and assistance required, as well as frequency of behaviours and neuroleptic use in the seven days prior to and following the trial of activities. Results Per participant, 5–11 interventions were prescribed. Most frequently interventions were tried two or more times (46%); 9% were not tried at all. Staff or family assistance was not required for 27% of activities. The mean number of documented behaviours across participants was 4.8 ± 2.3 in the pre-intervention period and 2.1 ± 1.9 in the post-intervention period. Overall the interventions were feasible and did not result in increasing neuroleptic use Conclusion Non-pharmacologic interventions may be feasible to implement in acute care. More research in this area is justified.