Biology subjects

Grey, C.

Publications and source records attributed to Grey, C..

6 recordsLinked to original sources

bioRxiv2025

Role of Chloroplast Lipid-Remodelling Protein 23 During Cold Acclimation in Arabidopsis thaliana

Cold acclimation is a crucial physiological process that enables plants to adapt to low temperatures. A key aspect of this adaptation is lipid remodeling, which preserves membrane fluidity and integrity under cold stress. Proteins of the chloroplast envelope membranes are increasingly recognized for their role in acclimation to changing environmental conditions. While lipid synthesis occurs at the inner envelope membrane, little is known about specific proteins involved in lipid remodeling during cold acclimation. In this study, we investigate the role of Chloroplast Lipid Remodeling Protein 23 (CLRP23) as a component of the inner chloroplast envelope membrane. Subcellular fractionation combined with protease protection assays provided evidence for its orientation toward the intermembrane space. To explore its function, we analyzed the physiological performance and lipid composition in CLRP23-deficient mutant plants. Under cold stress, we observed significant impairments in photosynthesis and exaggerations in galactolipid response, suggesting CLRP23 is involved in lipid remodeling. Lipid overlay assays, supported by in silico docking analyses, demonstrate that CLRP23 can directly interact with chloroplast lipids, including galactolipids. Complementary transcriptomic and proteomic analyses reveal broader effects on cold-responsive pathways, supporting the view that CLRP23 contributes to the integration of membrane and metabolic responses during acclimation. These findings expand our understanding of protein-mediated processes during cold acclimation.

plant biology↗

bioRxiv2023

Acinetobacter guillouiae strain isolated from sludge capable of partially degrade polyethylene terephthalate: genomic and biochemical insights

The escalating accumulation of plastic waste in terrestrial and aquatic ecosystems profoundly threatens environmental health and biodiversity while impacting human well-being. Recently, many microorganisms capable of degrading polyethylene terephthalate (PET) have been reported, primarily sourced from terrestrial soils and marine environments. Notably, the challenge of PET pollution in aquatic environments has remained a persistent research concern. In this study, we present the isolation and characterization of Acinetobacter guillouiae strain I-MWF, obtained from a wastewater treatment plant in Makri, AJK, Pakistan, using molecular phylogenetic analysis based on genome sequencing. Results revealed that this strain exhibits the ability for PET powder degradation, as confirmed by HPLC/LCMS analysis. Furthermore, we conducted whole-genome sequencing using Illumina technology and bioinformatically explored this strains potential repertoire of lipase and esterase enzymes. Under optimized conditions of 23{degrees}C and pH 7 in mineral salt media with PET powder as the sole organic substrate, A. guillouiae I-MWF could degrade partially. Extracellular enzymes yielded PET depolymerization products identified as mono(2- hydroxyethyl) terephthalic acid and terephthalic acid. The sequenced genome of this strain spans 4.61 Mb with a mean G + C content of 38.2%, containing 4,178 coding genes, 71 tRNA, and six rRNA genes. Although no cutinase-like enzymes were identified, our analysis unveiled a diverse array of putative lipases and three esterases, all sharing the typical /{beta} hydrolase fold. Additionally, comprehensive molecular modelling analysis suggested that some of the 18 identified extracellular hydrolases may be involved in polyester enzymatic depolymerization processes.

microbiology↗

bioRxiv2022

Infant low-frequency EEG cortical power, cortical tracking and phase-amplitude coupling predicts language a year later.

Cortical signals have been shown to track acoustic and linguistic properties of continuous speech. This phenomenon has been measured in both children and adults, reflecting speech understanding by adults as well as cognitive functions such as attention and prediction. Furthermore, atypical low-frequency cortical tracking of speech is found in children with phonological difficulties (developmental dyslexia). Accordingly, low-frequency cortical signals may play a critical role in language acquisition. A recent investigation with infants Attaheri et al., 2022 (1) probed cortical tracking mechanisms at the ages of 4, 7 and 11 months as participants listened to sung speech. Results from temporal response function (TRF), phase-amplitude coupling (PAC) and dynamic theta-delta power (PSD) analyses indicated speech envelope tracking and stimulus-related power (PSD) for delta and theta neural signals. Furthermore, delta- and theta-driven PAC was found at all ages, with theta phases displaying stronger PAC with high-frequency amplitudes than delta. The present study tests whether these previous findings replicate in the second half of the full cohort of infants (N = 122) who were participating in this longitudinal study (first half: N=61, (1); second half: N=61). In addition to demonstrating good replication, we investigate whether cortical tracking in the first year of life predicts later language acquisition for the full cohort (122 infants recruited, 113 retained) using both infant-led and parent-estimated measures and multivariate and univariate analyses. Increased delta cortical tracking in the univariate analyses, increased [~]2Hz PSD power and stronger theta-gamma PAC in both multivariate and univariate analyses were related to better language outcomes using both infant-led and parent-estimated measures. By contrast, increased [~]4Hz PSD power in the multi-variate analyses, increased delta-beta PAC and a higher theta/delta power ratio in the multi-variate analyses were related to worse language outcomes. The data are interpreted within a "Temporal Sampling" framework for developmental language trajectories.

neuroscience↗

bioRxiv2021

TOPOVIBL-REC114 interaction regulates meiotic DNA double-strand breaks

Meiosis requires the formation of programmed DNA double strand breaks (DSBs), essential for fertility and for generating genetic diversity. DSBs are induced by the catalytic activity of the TOPOVIL complex formed by SPO11 and TOPOVIBL. To ensure genomic integrity, DNA cleavage activity is tightly regulated, and several accessory factors (REC114, MEI4, IHO1, and MEI1) are needed for DSB formation in mice. How and when these proteins act is not understood. Here, we show that REC114 is a direct partner of TOPOVIBL, and identified their conserved interacting domains by structural analysis. We then analysed the role of this interaction by monitoring meiotic DSBs in female and male mice carrying point mutations in TOPOVIBL that decrease or disrupt its binding to REC114. In these mutants, DSB activity was strongly reduced genome-wide in oocytes, and only in sub-telomeric regions in spermatocytes. In addition, in mutant spermatocytes, DSB activity was delayed in autosomes. These results provide evidence that REC114 is a key member of the TOPOVIL catalytic complex, and that the REC114/TOPOVIBL interaction ensures the efficiency and timing of DSB activity.

molecular biology↗

bioRxiv2020

Delta- and theta-band cortical tracking and phase-amplitude coupling to sung speech by infants

The amplitude envelope of speech carries crucial low-frequency acoustic information that assists linguistic decoding at multiple time scales. Neurophysiological signals are known to track the amplitude envelope of adult-directed speech (ADS), particularly in the theta-band. Acoustic analysis of infant-directed speech (IDS) has revealed significantly greater modulation energy than ADS in an amplitude-modulation (AM) band centered on [~]2 Hz. Accordingly, cortical tracking of IDS by delta-band neural signals may be key to language acquisition. Speech also contains acoustic information within its higher-frequency bands (beta, gamma). Adult EEG and MEG studies reveal an oscillatory hierarchy, whereby low-frequency (delta, theta) neural phase dynamics temporally organize the amplitude of high-frequency signals (phase amplitude coupling, PAC). Whilst consensus is growing around the role of PAC in the matured adult brain, its role in the development of speech processing is unexplored. Here, we examined the presence and maturation of low-frequency (<12 Hz) cortical speech tracking in infants by recording EEG longitudinally from 60 participants when aged 4-, 7- and 11-months as they listened to nursery rhymes. After establishing stimulus-related neural signals in delta and theta, cortical tracking at each age was assessed in the delta, theta and alpha [control] bands using a multivariate temporal response function (mTRF) method. Delta-beta, delta-gamma, theta-beta and theta-gamma phase-amplitude coupling (PAC) was also assessed. Significant delta and theta but not alpha tracking was found. Significant PAC was present at all ages, with both delta and theta -driven coupling observed. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/329326v4_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@c7c7feorg.highwire.dtl.DTLVardef@1afa39org.highwire.dtl.DTLVardef@121d616org.highwire.dtl.DTLVardef@6e7c7b_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LILongitudinal EEG study in which 4, 7- & 11-month infants listened to nursery rhymes C_LIO_LIWe demonstrate cortical speech tracking via delta & theta neural signals (mTRF) C_LIO_LIPeriodogram (PSD) analysis revealed stimulus related delta & theta PSD peaks C_LIO_LIDelta and theta driven phase amplitude coupling (PAC) was found at all ages C_LIO_LIGamma frequency amplitudes displayed stronger PAC to low frequency phases than beta C_LI

neuroscience↗

bioRxiv2018

ANKRD31 regulates spatiotemporal patterning of meiotic recombination initiation and ensures recombination between heterologous sex chromosomes in mice

Orderly segregation of chromosomes during meiosis requires that crossovers form between homologous chromosomes by recombination. Programmed DNA double-strand breaks (DSBs) initiate meiotic recombination. We identify ANKRD31 as a critical component of complexes of DSB-promoting proteins which assemble on meiotic chromosome axes. Genome-wide, ANKRD31 deficiency causes delayed recombination initiation. In addition, loss of ANKRD31 alters DSB distribution owing to reduced selectivity for sites that normally attract DSBs. Strikingly, ANKRD31 deficiency also abolishes uniquely high rates of recombination that normally characterize pseudoautosomal regions (PARs) of X and Y chromosomes. Consequently, sex chromosomes do not form crossovers leading to chromosome segregation failure in ANKRD31-deficient spermatocytes. These defects are accompanied by a genome-wide delay in assembling DSB-promoting proteins on axes and a loss of a specialized PAR-axis domain that is highly enriched for DSB-promoting proteins. Thus, we propose a model for spatiotemporal patterning of recombination by ANKRD31-dependent control of axis-associated complexes of DSB-promoting proteins.

cell biology↗