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Due to envelope differences between Gram-positive and Gram-negative bacteria, engineering precision bactericidal contractile nanomachines requires atomic-level understanding of their structures; however, only those killing Gram-negative bacteria are currently known. Here, we report the atomic structures of an engineered diffocin, a contractile syringe-like molecular machine that kills the Gram-positive bacterium Clostridioides difficile. Captured in one pre-contraction and two post-contraction states, each structure fashions six proteins in the bacteria-targeting baseplate, two proteins in the energy-storing trunk, and a collar linking the sheath with the membrane-penetrating tube. Compared to contractile machines targeting Gram-negative bacteria, major differences reside in the baseplate and contraction magnitude, consistent with target envelope differences. The multifunctional hub-hydrolase protein connects the tube and baseplate and is positioned to degrade peptidoglycan during penetration. The full-length tape measure protein forms a coiled-coil helix bundle homotrimer spanning the entire diffocin. Our study offers mechanical insights and principles for designing potent protein-based precision antibiotics. R-type contractile bacteriocins are natural-occurring nanomachines that kill bacteria. Here the authors report the atomic structures of a bacteriocin, called diffocin, that has been engineered to kill Gram-positive bacterium Clostridioides difficile. [ABSTRACT FROM AUTHOR]

Ideomotor theory suggests that selecting a response is achieved by anticipating the consequences of that response. Evidence for this is the response-effect compatibility (REC) effect, that is, responding tends to be faster when the (anticipated) predictable consequences of a response (the action effects) are compatible rather than incompatible with the response. The present experiments investigated the extent to which the consequences must be exactly versus categorically predictable. According to the latter, an abstraction from particular instances to the categories of dimensional overlap might take place. For participants in one group of Experiment 1, left-hand and right-hand responses produced compatible or incompatible action effects in perfectly predictable positions to the left or right of fixation, and a standard REC effect was observed. For participants in another group of Experiment 1, as well as in Experiments 2 and 3, the responses also produced action effects to the left or right of fixation, but the eccentricity of the action effects (and thus their precise location) was unpredictable. On average, the data from the latter groups suggest that there is little, if any, tendency for participants to abstract the critical left/right features from spatially somewhat unpredictable action effects and use them for action selection, although there were large individual differences in these groups. Thus, at least on average across participants, it appears that the spatial locations of action effects must be perfectly predictable for these effects to have a strong influence on the response time. [ABSTRACT FROM AUTHOR]

A common finding across numerous response time (RT) paradigms is that the mean RT in one trial depends strongly on the characteristics of the immediately preceding trial. Although such sequential effects have usually only been considered within each single paradigm in isolation from the others, there are important similarities across paradigms between the theoretical accounts of these effects. However, so far there has been no systematic comparison of sequential effects across paradigms. To investigate the possible relationships between sequential effects in different paradigms, we conducted an experiment examining sequential effects in visual search, two-choice RT, interference, and task-switching paradigms, using methods designed to maximize the similarity of stimuli and responses across paradigms. Detailed analyses of the observed RT distributions were carried out using both descriptive (e.g., ex-Gaussian) and process-oriented (e.g., diffusion models) methods. The results reveal significant empirical similarities and differences between the sequential effects observed across different paradigms, and in some cases even across different conditions within a single paradigm. Furthermore, the sequential effects are more similar to one another for some pairs of paradigms than for others. These results imply that some cognitive processes eliciting sequential effects are shared across paradigms while others seem to be paradigm-specific., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

The seedcorn maggot, Delia platura (Meigen), is a pest affecting many crops, including corn. The early spring emergence of adults and belowground seed damage by maggots leave no room for rescue treatments during the short growing season in New York State. Degree-day (DD) models play a crucial role in predicting insect emergence and adult peak activity and are essential for effective pest management. The current D. platura DD model was launched on the Network for Environment and Weather Applications (NEWA) in 2022, using existing scientific literature from other North American regions. The NEWA model predicted adult D. platura first emergence at an average of 471 (39°F) DD in 2022. To gain an accurate and precise understanding of D. platura adult spring emergence and activity, we used interpolated temperature data to calculate the DD for each specific location where adults were captured in the field. DD calculations were performed using the average method, setting a biofix on January 1st and a base temperature of 39°F. In 2023, overwintering adults emerged at an average of 68 DD, and in 2022, adult activity was registered at an average of 282 DD. Accurately predicting the emergence of D. platura could contribute to informing integrated pest management strategies that incorporate timing and cultural practices over chemical solutions to protect crops and the environment., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)