Intraspecies and Interspecies Transformation Reactions in Pneumococcus and Streptococcus

The efficiency of transformation of pneumococcus and a strain of viridans streptococcus (strain D) to streptomycin resistance is influenced by the species in which the mutation to resistance occurred, as well as by the species in which the mutated gene has been replicated. Pneumococcus and streptococcus strain D transform in higher frequency with DNA that has been replicated in bacteria of the same species than with DNA from the heterologous species. However, the difference between the frequencies of interspecific and intraspecific transformation is much greater with pneumococcus as receptor than with streptococcus. In addition pneumococcus transforms in higher frequency with wholly homologous (pneumococcal) DNA than with DNA from pneumococci that have replicated the streptococcal Sm^r gene. Pneumococcus is transformed in lower frequency by wholly heterologous (streptococcal) DNA than by DNA from streptococci that have replicated the pneumococcal Sm^r gene. Streptococcus behaves similarly in that wholly homologous (streptococcal) DNA transforms it more efficiently than when the transforming fragment contains a pneumococcal moiety. Streptococcus is transformed in the same or lower frequency by wholly heterologous (pneumococcal) DNA than by DNA from pneumococci that have replicated the streptococcal Sm^r gene. When erythromycin resistance was used as genetic marker instead of streptomycin resistance, similar results were found.     

Increasing the Time Resolution of Single-Molecule Experiments with Bayesian Inference

Many time-resolved single-molecule biophysics experiments seek to characterize the kinetics of biomolecular systems exhibiting dynamics that challenge the time resolution of the given technique. Here, we present a general, computational approach to this problem that employs Bayesian inference to learn the underlying dynamics of such systems, even when they are much faster than the time resolution of the experimental technique being used. By accurately and precisely inferring rate constants, our Bayesian inference for the analysis of subtemporal resolution dynamics approach effectively enables the experimenter to super-resolve the poorly resolved dynamics that are present in their data.     

Solar radiation and ENSO predict fruiting phenology patterns in a 15‐year record from Kibale National Park,Uganda

Fruiting, flowering, and leaf set patterns influence many aspects of tropical forest communities, but there are few long‐term studies examining potential drivers of these patterns, particularly in Africa. We evaluated a 15‐year dataset of tree phenology in Kibale National Park, Uganda, to identify abiotic predictors of fruit phenological patterns and discuss our findings in light of climate change. We quantified fruiting for 326 trees from 43 species and evaluated these patterns in relation to solar radiance, rainfall, and monthly temperature. We used time‐lagged variables based on seasonality in linear regression models to assess the effect of abiotic variables on the proportion of fruiting trees. Annual fruiting varied over 3.8‐fold, and inter‐annual variation in fruiting is associated with the extent of fruiting in the peak period, not variation in time of fruit set. While temperature and rainfall showed positive effects on fruiting, solar radiance in the two‐year period encompassing a given year and the previous year was the strongest predictor of fruiting. As solar irradiance was the strongest predictor of fruiting, the projected increase in rainfall associated with climate change, and coincident increase in cloud cover suggest that climate change will lead to a decrease in fruiting. ENSO in the prior 24‐month period was also significantly associated with annual ripe fruit production, and ENSO is also affected by climate change. Predicting changes in phenology demands understanding inter‐annual variation in fruit dynamics in light of potential abiotic drivers, patterns that will only emerge with long‐term data.     

Counterintuitive migration patterns by Atlantic salmon Salmo salar smolts in a large lake

What little is known about the seaward migration of Salmo salar smolt migration through standing waters indicates that it is both slow and results in high mortality rates, compared with riverine migration. This may be partly because smolts in lakes need to swim more actively and require more complex directional cues than they do in rivers. In this telemetry study of smolt migration through Loch Lomond, S. salar smolts made repeated movements in directions away from the outflowing river, which considerably increased migration time.