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Kejzar, N.

Publications and source records attributed to Kejzar, N..

2 recordsLinked to original sources

A novel fully-automated system for lifelong continuous phenotyping of mouse cognition and behaviour

Comprehensive ethologically-relevant behavioural phenotyping in rodent experiments is essential for deciphering the neural basis of animal cognition. Automated home-cage monitoring systems present a valuable tool to fulfil this need. However, they often involve complex animal training routines, water or food deprivation, and probe a limited range of behaviours. Here, we present a new fully automated AI-driven home-cage system for cognitive and behavioural phenotyping in mice. The system incorporates spontaneous alternation T-maze, novel-object recognition and object-in-place recognition tests combined with monitoring of an animals position, water consumption, quiescence and locomotion patterns, all carried out continuously and simultaneously in an unsupervised fashion over long periods of time. Mice learnt the tasks rapidly without any need for water or food restrictions. We applied ethomics approach to show that combined statistical properties of multiple behaviours can be used to discriminate between mice with hippocampal, medial entorhinal and sham lesions and accurately predict genotype of Alzheimers disease mouse models on an individual animal level, surpassing the performance of several gold standard cognitive tests. This technology could enable large-scale behavioural screening for genes and neural circuits underlying spatial memory and other cognitive processes.

neuroscience↗

New Vista into Origins of Viruses from a Prototypic ssDNA Phage

Viruses play a central role in all ecological niches; the origin of viruses, however, remains an open question. While phylogenetic analysis of distantly related viruses is hampered by a lack of detectable sequence similarity, structural biology can reveal conserved capsid protein structures that facilitate the study of distant evolutionary relationships. Here, we characterize the lipid-containing ssDNA temperate bacteriophage {Phi}CjT23, which is infecting Flavobacterium sp. (Bacteroidetes). We further detected {Phi}CjT23-like sequences in the genome of strains belonging to several Flavobacterium species. The virion structure determined by cryogenic electron microscopy revealed similarities to members of the viral kingdom Bamfordvirae that currently consists solely of dsDNA viruses. Common to these viruses, infecting hosts from all domains of life, is a major capsid protein composed of two upright {beta}-sandwiches. The minimalistic structure of {Phi}CjT23 suggests that this phage serves as a model for the last common ancestor between ssDNA and dsDNA viruses in the Bamfordvirae. Both {Phi}CjT23 and the related phage FLiP infect Flavobacterium species found in several environments, suggesting that these types of viruses have a global distribution and shared evolutionary origin. Detailed comparisons to related, more complex viruses not only expand our knowledge about this group of viruses but also provide a rare glimpse into early virus evolution.

microbiology↗