Biology subjects

Wong, Y. K.

Publications and source records attributed to Wong, Y. K..

3 recordsLinked to original sources

bioRxiv2023

Trans-complementation by the RecB nuclease domain of RecBCD enzyme reveals new insight into RecA loading upon χ recognition

The loading of RecA onto ssDNA by RecBCD is an essential step of RecBCD-mediated homologous recombination. RecBCD facilitates RecA-loading onto ssDNA in a {chi}-dependent manner via its RecB nuclease domain (RecBn). Before recognition of {chi}, RecBn is sequestered through interactions with RecBCD. It was proposed that upon {chi}-recognition, RecBn undocks, allowing RecBn to swing out via a contiguous 70 amino acid linker to reveal the RecA-loading surface, and then recruit and load RecA onto ssDNA. We tested this hypothesis by examining the interactions between RecBn (RecB928-1180) and truncated RecBCD (RecB1-927CD) lacking the nuclease domain. The reconstituted complex of RecB1-927CD and RecBn is functional in vitro and in vivo. Our results indicate that despite being covalently severed from RecB1-927CD, RecBn can still load RecA onto ssDNA, establishing that RecBn does not function at the end of its flexible linker. Instead, RecBCD undergoes a {chi}-induced intramolecular rearrangement to reveal a RecA-loading surface.

biochemistry↗

bioRxiv2020

The Effect of Task on Object Processing revealed by EEG decoding

Recent studies showed that task demand affects object representations in higher-level visual areas and beyond, but not so much in earlier areas. There are, however, limitations in those studies including the relatively weak manipulation of task due to the use of familiar real-life objects, the low temporal resolution in fMRI, and the emphasis on the amount and not the source of information carried by brain activations. In the current study, observers categorized images of artificial objects in one of two orthogonal dimensions, shape and texture, while their brain activity was recorded with electroencephalogram (EEG). Results showed that object processing along the texture dimension was affected by task demand starting from a relatively late time (320-370ms time window) after image onset. The findings are consistent with the view that task exerts an effect on the later phases of object processing.

neuroscience↗

bioRxiv2018

Acquiring absolute pitch in adulthood is difficult but possible

Absolute pitch (AP) refers to the rare ability to name the pitch of a tone without external reference. It is widely believed that AP is only for the selected few with rare genetic makeup and early musical training during the critical period. Accordingly, acquiring AP in adulthood is impossible. Previous studies have not offered a strong test of the effect of training because of issues like small sample size and insufficient training. In three experiments, adults learned to name pitches in a computerized and personalized protocol for 12 to 40 hours. They improved considerably, with a continuous distribution of learning progress among them. 14% of the participants (6 out of 43) were able to name twelve pitches at accuracy of 90% or above, comparable to that of AP possessors as defined in the literature. In general, AP learning showed classic characteristics of perceptual learning, including generalization of learning dependent on the training stimuli, and sustained improvement for at least one to three months. Overall, the finding that AP continues to be learnable in adulthood calls for reconsidering the role of learning in the occurrence of AP. The finding also pushes the field to pinpoint and explain, if any, the differences between the aspects of AP more trainable in adulthood and the aspects of AP that are potentially exclusive for the few exceptional AP possessors.

animal behavior and cognition↗