Biology subjects

Ilyas, A.

Publications and source records attributed to Ilyas, A..

6 recordsLinked to original sources

bioRxiv2025

Enhancement of Arabidopsis growth by Enterobacter sp. SA187 under elevated CO2 is dependent on ethylene signalling activation and primary metabolism reprogramming

As atmospheric CO2 levels continue to increase, optimizing the CO2 fertilization effect which often falls short of its potential due to the physiological and metabolic limitations of plants becomes crucial. This study investigates the role of Enterobacter sp. SA187 (SA187), a plant growth-promoting bacterium, in enhancing growth and development of Arabidopsis thaliana under elevated atmospheric CO2 (eCO2) conditions. While SA187 inoculation did not have major effects under ambient CO2, it was found to significantly enhance root and shoot biomass, and to increase N- and reduce C-contents under eCO2. Moreover, transcriptomics and metabolomics suggested that SA187 modulated phytohormonal homeostasis, with activation of the salicylic acid, jasmonic acid and ethylene signalling pathways, and increased primary metabolism including the TCA cycle, N and carbohydrate metabolisms. Finally, the growth-promoting effects of SA187 were shown to be mediated through ethylene-dependent pathways, as evidenced with the ethylene-insensitive mutant ein2-1 which did not show similar benefits in plant fresh weight and altered gene expression. This beneficial plant-microbe interaction under eCO2 in a non-leguminous plant highlights a novel aspect of microbial influence on plant physiology in the context of climate change. These insights underscore the potential of utilizing SA187 to enhance plant performance and adaptability in future high CO2 environments, providing a sustainable approach to agricultural productivity as global CO2 levels increase.

plant biology↗

bioRxiv2025

Enterobacter sp. SA187-induced coordinated regulation of high-affinity nitrate transporters and ethylene signaling enhances nitrogen content and plant growth under low nitrate

O_LISustainable crop production demands solutions to reduce the overuse of synthetic nitrogen fertilizers, and plant-growth-promoting bacteria offer a promising strategy by enhancing nutrients acquisition. This study investigated ability of a non-diazotrophic bacterium, Enterobacter sp. SA187 (SA187), in enhancing Arabidopsis growth under low nitrate conditions and the underlying mechanisms. C_LIO_LIArabidopsis seedlings were grown under different nitrate concentrations with or without SA187 inoculation. Growth traits were quantified alongside shoot and root nitrate and total nitrogen contents, and C:N ratios. Transcriptomic profiling (RNA-seq) and qRT-PCR were used to assess modified gene expression. Functional validation was conducted using ethylene-insensitive (ein2-1) and high-affinity nitrate transporter (HATS) mutants (nrt2.5, nrt2.6). C_LIO_LISA187 significantly enhanced fresh weight, primary root length, and lateral root density under low nitrate, with benefits increasing as nitrate availability decreased. SA187 improved nitrate accumulation and shoot nitrogen allocation, reducing shoot C:N ratios. SA187 regulated expression of HATS and hormone-responsive genes. The growth-promoting effects were abolished in ein2-1, nrt2.5, and nrt2.6 mutants, and SA187-induced regulation of NRT2.5 occurred downstream of ethylene signaling, while NRT2.6 was partly ethylene-independent. C_LIO_LISA187 promotes growth under low nitrate possibly through ethylene-mediated and HATS-dependent reprogramming of nitrate accumulation and nitrogen allocation, supporting its use as a microbial solution for low-input agriculture. C_LI

plant biology↗

bioRxiv2020

Anterior Nucleus of Thalamus Gates Progression of Mesial Temporal Seizures by Modulating Thalamocortical Synchrony

The anterior nucleus of the thalamus (ANT) mediates cortical-subcortical interactions between the limbic system and is hypothesized to facilitate the early organization of temporal lobe seizures. We set out to investigate the dynamic changes in synchronization parameters between the seizure onset zone (SOZ) and ANT during seizure stages (pre-onset to post-termination) in seven patients (n=26 seizures) with drug-resistant nonlesional temporal lobe epilepsy. Using local field potentials recorded directly from the limbic system and the ANT during stereoelectroencephalography, we confirm that the onset of mesial temporal lobe seizure is associated with increased thalamocortical network excitability and phase-amplitude coupling. The increase in thalamocortical phase synchronization preceded seizure onset, thereby suggesting that the early organization of temporal lobe seizures involves the integration of the ANT within the epileptic network. Towards seizure termination, there is a significant decrease in thalamic excitability, thalamocortical synchronization, and decoupling, thereby suggesting a breakdown in thalamocortical connectivity. A higher disease burden is significantly correlated with increased synchronization between the ANT and epileptic networks. Collectively, the results elucidate mechanistic insights and provide the temporal architecture of thalamocortical interactions that can be targeted in the rational designing of closed-loop seizure abortive interventions. HighlightsO_LIAnterior nucleus of thalamus is coactivated at the onset of temporal lobe seizures C_LIO_LIIncrease thalamocortical synchronization and excitability is observed at seizure onset C_LIO_LISeizure termination is characterized by a breakdown in thalamocortical connectivity C_LIO_LIIncreased seizure burden affects thalamocortical synchronization C_LI

neuroscience↗

bioRxiv2020

Implantation technique, safety and complications of robot-assisted stereoelectroencephalography exploration of the limbic thalamus in human focal epilepsy

IntroductionDespite numerous imaging studies highlighting the importance of thalamus in surgical prognosis, human electrophysiological studies involving the limbic thalamic nuclei are limited. The objective of this study was to evaluate the safety and accuracy of robot-assisted stereotactic electrode placement in the limbic thalamic nuclei in patients with suspected temporal lobe epilepsy (TLE). MethodsAfter obtaining informed consent, 24 adults with drug-resistant suspected TLE undergoing Stereo-EEG evaluation were enrolled in this prospective study. The trajectory of one electrode planned for clinical sampling the operculo-insular cortex was modified to extend to the thalamus, thereby preventing the need for additional electrode placement for research. The anterior thalamus (ANT) (N=13) and the medial group of thalamic nuclei (MED) (N=11), including mediodorsal (MD) and centromedian (CeM) were targeted. The post-implantation CT was co-registered to the pre-operative MRI, and Morels thalamic atlas was used to confirm the accuracy of implantation. ResultsTen out of 13 (77%) in the ANT group and 10 out of 11 patients (90%) in the medial group had electrodes accurately placed in the thalamic nuclei. None of the patients had a thalamic hemorrhage. However, trace asymptomatic hemorrhages at the cortical level entry site were noted in 20.8% of patients and they did not require additional surgical intervention. SEEG data from all the patients were interpretable and analyzable. The trajectories for the ANT implant differed slightly from the medial group at the entry point i.e., precentral gyrus in the former and postcentral gyrus in the latter. ConclusionsUsing judiciously planned robot-assisted SEEG, we demonstrate the safety of electrophysiological sampling from various thalamic nuclei for research recordings, presenting a technique that avoids implanting additional depth electrodes, or comprising clinical care. With these results, we propose that if patients are fully informed of the risks involved, there are potential benefits of gaining mechanistic insights to seizure genesis, which may help to develop neuromodulation therapies.

neuroscience↗

bioRxiv2019

Ictal recruitment of anterior nucleus of thalamus in human focal epilepsy

The thalamic nuclei play diverse roles in the initiation, propagation, and termination of temporal lobe seizures. The role of the anterior nucleus of the thalamus (ANT) - a node that is integral to the limbic network is unclear. The objective of this study was to characterize temporal and - spectral patterns of ANT ictal recruitment in drug-resistant temporal lobe epilepsy (TLE). We hypothesized that seizures localized to the temporolimbic network are likely to recruit ANT, and the odds of recruitment were higher in seizures that had altered consciousness. Ten patients undergoing stereo-electroencephalography (SEEG) were recruited prospectively to record field potentials from the ANT. Using epileptogenicity index and line length, we computed the number of seizures that recruited the ANT (recruitment ratio), the recruitment latencies between the ANT and the epileptogenic zone (EZ), and latency of ANT recruitment to clinical manifestation for seventy-nine seizures. We observed that seizures localized to mesial temporal subregions (hippocampus, amygdala, anterior cingulate) have a higher predilection for ANT recruitment, and the recruitment was faster (ranged 5-12 secs) and preceded clinical onset for seizures that impaired consciousness. Seizures that recruited ANT lasted significantly longer (t=1.795, p=0.005). Recruitment latency was inversely correlated to seizure duration (r=-0.78, p=0.004). Electrical stimulation of the EZ induced seizures, in which early recruitment of ANT was confirmed. Stimulation of ANT did not induce a seizure. Finally, we tested the hypothesis that spectral and entropy-based features extracted from thalamic field potentials can distinguish its state of ictal recruitment from other interictal states (including awake, sleep). For this, we employed classification machine learning that discriminated thalamic ictal state from other interictal states with high accuracy (92.8%) and precision (93.1%). Among the features, the emergence of the theta rhythm (4-8 Hz) maximally discriminated the endogenous ictal state from other interictal states of vigilance. These results prompt a mechanistic role for the ANT in the early organization and sustaining of seizures, and the possibility to serve as a target for therapeutic closed-loop stimulation in TLE.

neuroscience↗

bioRxiv2019

Early Ictal Recruitment of Midline Thalamus in Mesial Temporal Lobe Epilepsy

The causal role of midline thalamus in the initiation and early organization of mesial temporal lobe seizures is studied. Three patients undergoing stereoelectroencephalography were enrolled for the placement of an additional depth electrode targeting the midline thalamus. The midline thalamus was recruited in all three patients at varying points of seizure initiation (0-13 seconds) and early propagation (9-60 seconds). Stimulation of either thalamus or hippocampus induced similar habitual seizures. Seizure-induced in the hippocampus rapidly recruited the thalamus. Evoked potentials demonstrated stronger connectivity from the hippocampus to the thalamus than in the opposite direction. The midline thalamus can be within the seizure initiation and symptomatogenic circuits.

neuroscience↗