Biology subjects

Macia, J.

Publications and source records attributed to Macia, J..

3 recordsLinked to original sources

bioRxiv2024

CHARACTERIZATION OF RECOMBINASE ACTIVITY ACROSS CELLULAR GROWTH PHASES

Recombinases, which are enzymes that catalyze targeted DNA modifications, hold significant potential in synthetic biology. Their capacity to precisely manipulate genetic material enables the construction of complex genetic circuits that can be dynamically reconfigured in response to environmental stimuli. Such capabilities are essential for developing synthetic organisms tailored for specific functions, including biosensing, bioremediation, and pharmaceutical production. Therefore, characterizing the dynamics of recombinases is crucial for the innovative design of cellular devices. A deeper understanding of how recombinases interact with DNA in various conditions can improve the efficiency and control of genetic modifications, thereby enhancing both the functionality and reliability of synthetic biological systems. This study presents a detailed examination of the dynamics and efficiency of the serine recombinase Bxb1, focusing on its behavior under controlled expression in Escherichia coli. It highlights the significant influence of cellular growth phases (exponential and stationary) on the efficiency of recombinase-mediated gene expression. Our findings show that recombinase activity is maintained during stationary phase, which is critical to ensure ongoing recombination without the need for the continuous presence of an inducer. In experiments, we quantified the recombination efficiency of Bxb1 by monitoring expression of green fluorescent protein (GFP) as a reporter. Optimal expression of Bxb1, which maximized the recombination efficiency, occurred during exponential phase. However, once the culture reached stationary phase, accumulated Bxb1 continued to facilitate recombination, although GFP expression levels plateaued due to reduced cellular activity. These insights are relevant for synthetic biology applications where precise control of genetic functions is necessary.

synthetic biology↗

bioRxiv2024

Irregular light schedules induce alterations on daily rhythms and gene expression in mice

Synchronization of internal biological rhythms with external light-dark cycles is crucial for proper function and survival of the organisms, however modern life often imposes irregular light exposure, disrupting these internal clocks. This study investigated the effects of short-term shifted light-dark cycles on mice rhythmicity, and whether these alterations trigger molecular or behavioral changes. We evaluated locomotor activity, different behavioral domains and gene expression in the hypothalamus and medial prefrontal cortex. Despite non prominent behavioral impairments, such as anxiety or cognitive deficits, we observed a notable simplification in the locomotor activity patterns of the mice subjected to disrupted light-dark cycles. Molecular alterations included dysregulations in oscillations of core clock genes (Cry2, Per2) and disruptions in expression of genes involved in neuroplasticity, motivation, and stress responses, including GluA1, Crhr2, and Vip in both studied brain areas. Our study reveals that even brief light cycle shifts can disrupt circadian regulation at the molecular level, despite minimal behavioral changes. This molecular-behavioral discrepancy may suggest a complex adaptive response to drastic short-term light perturbations. Understanding the complex interplay between external light cues and internal biological rhythms regulation is crucial for mitigating the negative consequences of irregular light exposure on physiological processes and overall well-being.

neuroscience↗

bioRxiv2024

Lack of rhythmicity in Bmal1 deficient mice impairs motivation towards natural stimuli.

Maintaining appropriate circadian rhythmicity is essential for coordinating the activity of biological functions in mammalian organisms. A variety of physiological and behavioral changes have been associated with disturbances of this complex clock mechanism. In the present study, we delve into the consequences of circadian arrhythmia using the Bmal1-knockout (KO) mouse line aiming to explore potential behavioral and motivational implications. We were able to identify the intricate activity patterns that define circadian disturbance in Bmal1-KO mice by utilizing a new analysis model based on entropy divergence. Alterations in locomotor activity were accompanied by disruptions of circadian expression patterns in various clock genes as revealed by gene expression analysis. Additionally, we found a dysregulated gene expression profile in Bmal1-KO mice regarding genes related to circadian control in various brain nuclei. Specifically, the ventral striatum exhibited a dysregulation in the expression levels of genes modulating reward and motivation. Further investigation revealed that BMAL1 deficient mice showed a sustained rise in motivation and seeking behavior for food and water reinforcers in the self-administration paradigm, independently of the caloric content of the reward. Together, our data reveal that disruptions in circadian rhythmicity, induced by alterations in the molecular clock, also impact the gene expression regulating the reward system. This, in turn, can lead to altered seeking behavior and motivation for natural rewards. In summary, the present study contributes to our understanding of how reward processing is under the regulation of circadian clock machinery.

neuroscience↗