Biology subjects

Perez, B.

Publications and source records attributed to Perez, B..

3 recordsLinked to original sources

bioRxiv2022

Circadian rhythms in multiple behaviors depend on sex, neuropeptide signaling, and ambient light

Organisms have evolved circadian (near-24 h) rhythms in behavior to anticipate daily opportunities and challenges such as mating and predation. However, the ethological investigation of circadian behavioral rhythms has been traditionally limited to studying easy-to-measure behaviors at higher temporal resolution or difficult-to-measure behaviors with limited temporal resolution. Our ability to simultaneously record circadian rhythms in multiple behaviors has also been limited by currently available technology. We thus sought to examine eight overt, ethologically-relevant behaviors never before studied simultaneously as a function of time of day: eating, drinking, grooming, rearing, nesting, digging, exploring, and resting. To address the hypothesis that the daily patterning of these behaviors depends on neuropeptide signaling, sex, and ambient light, we used high-throughput machine learning to automatically score millions of video frames of freely-behaving male and female wild-type and vasoactive intestinal peptide (Vip)-deficient mice. Automated frame-by-frame predictions of the eight behaviors correlated highly with consensus labels by trained human classifiers. We discovered reliable daily rhythms in many previously unreported behaviors that peaked at stereotyped times of day and persisted in constant darkness. Surprisingly, nesting and digging rhythms differed dramatically in both phase and amplitude between male and female mice. In Vip-deficient mice, daily rhythms in most behaviors were low amplitude and peaked earlier in the day in a light:dark cycle, while rhythms in all behaviors peaked randomly throughout the day in constant darkness. We also found that for most behaviors, time budgets predominantly differed by light cycle, but transition probabilities predominantly differed with VIP signaling and by sex. We conclude that machine learning can be used to reveal novel sex, neuropeptide, and light-dependent behaviors at time scales from seconds to days.

animal behavior and cognition↗

bioRxiv2021

ALLOPURINOL BLOCKS THE FORMATION AND PROGRESSION OF AORTIC ANEURYSM IN A MOUSE MODEL OF MARFAN SYNDROME ACTING AS SCAVENGER OF REACTIVE OXYGEN SPECIES

BackgroundIncreasing evidence indicates that redox stress participates in MFS aortopathy, though its mechanistic contribution is little known. We reported elevated reactive oxygen species (ROS) formation and NADPH oxidase NOX4 upregulation in MFS patients and mouse aortae. Here we address the contribution of xanthine oxidoreductase (XOR), which catabolizes purines into uric acid and ROS in MFS aortopathy. Methods and ResultsIn aortic samples from MFS patients, XOR protein expression, revealed by immunohistochemistry, increased in both the tunicae intima and media of the dilated zone. In MFS mice (Fbn1C1041G/+), aortic XOR mRNA transcripts and enzymatic activity of the oxidase form (XO) were augmented in the aorta of 3-month-old mice but not in older animals. The administration of the XOR inhibitor allopurinol (ALO) halted the progression of aortic root aneurysm in MFS mice. ALO administrated before the onset of the aneurysm prevented its subsequent development. ALO also inhibited MFS-associated endothelial dysfunction as well as elastic fiber fragmentation, fibrotic collagen remodeling, nuclear translocation of pNRF2 and increased 3-nitrotyrosine levels all occurring in the tunica media. ALO reduced the MFS-associated large aortic production of H2O2, and NOX4 and MMP2 transcriptional overexpression. ConclusionsAllopurinol interferes in aortic aneurysm progression acting as a potent antioxidant. This study strengthens the concept that redox stress is an important determinant of aortic aneurysm formation and progression in MFS and warrants the evaluation of ALO therapy in MFS patients. HIGHLIGHTSO_LIXanthine oxidoreductase (XOR) is upregulated in the aortic aneurysm of Marfan syndrome (MFS) both in patients and young mice. C_LIO_LIAllopurinol halts the formation and progression of aortic aneurysm in MFS mice C_LIO_LIAllopurinol reduces a variety of oxidative stress-associated molecular reactions. C_LIO_LIAllopurinol prevents MFS endothelial-dependent vasodilator dysfunction. C_LIO_LIThe antioxidant action of allopurinol suggests its repositioning for pharmacological use in MFS aortopathy. C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=146 SRC="FIGDIR/small/464182v5_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1e6f784org.highwire.dtl.DTLVardef@84075eorg.highwire.dtl.DTLVardef@1ffcb5borg.highwire.dtl.DTLVardef@800503_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2021

SIBR-Cas enables host-independent and universal CRISPR genome engineering in bacteria

CRISPR-Cas is a powerful tool for genome editing in bacteria. However, its efficacy is dependent on host factors (such as DNA repair pathways) and/or exogenous expression of recombinases. In this study, we mitigated these constraints by developing a simple and universal genome engineering tool for bacteria which we termed SIBR-Cas (Self-splicing Intron-Based Riboswitch-Cas). SIBR-Cas was generated from a mutant library of the theophylline-dependent self-splicing T4 td intron that allows for universal and inducible control over CRISPR-Cas counterselection. This control delays CRISPR-Cas counterselection, granting more time for the editing event (e.g., by homologous recombination) to occur. Without the use of exogenous recombinases, SIBR-Cas was successfully applied to knock-out several genes in three bacteria with poor homologous recombination systems. Compared to other genome engineering tools, SIBR-Cas is simple, tightly regulated and widely applicable for most (non-model) bacteria. Furthermore, we propose that SIBR can have a wider application as a universal gene expression and gene regulation control mechanism for any gene or RNA of interest in bacteria.

bioengineering↗