Biology subjects

Miao, G.

Publications and source records attributed to Miao, G..

6 recordsLinked to original sources

bioRxiv2026

Deep learning-based decoding of axonal ultrastructure in gene-edited mice using electron microscopy imaging

Myelin forms an insulating sheath around axons enabling both rapid and energy-efficient conduction of action potentials and myelin abnormalities or loss can lead to severe motor, sensory, and cognitive impairment. While electron microscopy can resolve multiple axonal components that are affected myelin, their large-scale quantitative analysis is both difficult and time consuming. To overcome such limitations, we developed a machine learning framework that automatically recognizes and quantifies multiple features of axons and myelin including axonal mitochondrial density and periaxonal area. Applying that framework to fibers in the spinal cord of variably hypomyelinated mice, we show here that reduction in the thickness and length of myelin sheaths results in correlating changes in mitochondrial density and periaxonal area. The machine learning framework introduced here should contribute to future insight into the axon, myelin, and mitochondrial relationships that change during neurological plasticity and myelin disease progression.

neuroscience↗

bioRxiv2025

Molecular Insights into Cell Wall Architecture and Xylan-Bound Cellulose Fibrils in the Wheat Straw

The plant cell wall, a highly abundant renewable resource, remains insufficiently understood in terms of its structure, particularly the architecture of cellulose microfibrils and their interactions with hemicellulose and lignin, which impede the development of efficient downstream conversion. Here we present an alternative model of xylan-bound cellulose microfibril architecture in the cell wall of intact wheat straw, using solid-state nuclear magnetic resonance (ssNMR) coupled with X-ray scattering techniques. We show that the spectroscopic and scattering data can be fit to a simple elementary microfibril consisting of 18 glucan chains, with additional contributions from 0 to 4 tightly bound flat-ribbon xylan chains across the cellulose fibril axis. These xylan-bound cellulose microfibrils are found to serve as the secondary interaction site with lignin, following the non-flat xylan domains. The loose packing of these xylan-bound cellulose fibrils results in a heterogenous hydration landscape within the cell wall, allowing water penetration while maintaining structural integrity through numerous physical contacts between the polymers. This study provides a potential framework to reconcile the mounting biochemical evidence supporting the 18-chain elementary cellulose microfibril model and cellulose synthase complex with the oversized observations from characterization techniques, which report averaged structures influenced by microfibril coalescence and hemicellulose binding. The structural insights also offer valuable information regarding recalcitrance and the potential applications of biomass in biorefinery operations.

biochemistry↗

bioRxiv2023

Spotted fever group rickettsiae were the dominant pathogens in parasitic Rhipicephalus microplus in Yunnan Province, China*

ObjectiveTicks as ectoparasites might carry many pathogens and transmitted to their hosts through blood feeding. Human might have the opportunity to be bite by ticks, therefore getting various tick-borne pathogens. Distribution of bacterium flora in ticks plays an essential role in mapping and preventing local tick-borne diseases. Our aim is to map the distribution of bacterium flora and identify the main tick-borne pathogens in dominant tick species in grazing areas of Yunnan province. MethodsV3-V4 region of 16S rRNA amplifier sequencing was used to analyze and study the tick-borne pathogens in Rh. Microplus. The prevalence survey on B.burgdorferi s.l., B. miyamotoi, E. chaffeensis, A. phagocytophilum, Coxiella burnetii and Spotted fever group rickettsiae was carried out via PCR. ResultsThe results showed 105 genus and 117 species were detected in 50 (24 in Yunpan, 26 in Menghun) ticks. Pathogen prevalence testing showed the ticks were positive for B.burgdorferi s.l.(9/50, 18%), Spotted fever group rickettsiae (35/50, 70%), and A.phagocytophilum (1/50, 2%). ConclusionIn our analysis, Spotted fever group rickettsiae were the dominant pathogens in these areas. At the same time, we found that v3-v4 high-throughput sequencing of 16S rRNA gene is not sensitive to identify species for certain bacteria(such as B. burgdorferi s.l.). More accurate and comprehensive analysis would be necessary for detecting tick bacterium flora.

molecular biology↗

bioRxiv2022

PDR6-mediated camalexin efflux and disease resistance are regulated through direct phosphorylation by the kinases OXI1 and AGC2-2

Plant immune signaling largely relies on post-translational modifications to establish a rapid and appropriate defense response to different pathogen types and infection pressure. Specific pleiotropic drug resistance (PDR) transporters can transport secondary metabolites to contribute to pathogen invasion resistance. However, the establishment of the post-translational regulation of PDR transporters that efflux secondary metabolites is unclear. In this study, by detecting the camalexin contents on the leaf surfaces of mutants and overexpression lines, two AGC kinases, namely, OXI1 and its closest homologue AGC2-2, were found to be related to extracellular camalexin secretion. The overexpression of OXI1 or AGC2-2 resulted in an increase in camalexin contents on the leaf surface and a decrease in camalexin contents in the leaf interior. These effects increased the resistance of the transgenic lines to surface-inoculated Pseudomonas syringae and Botrytis cinerea. Through in vitro kinase assay and in vivo phosphorylation level detection, we confirmed that the two kinases were related to the phosphorylation modification of PDR6. Pull-down assays, bimolecular fluorescence complementation, and rapamycin-dependent delocalization assays indicated the existence of direct protein-protein interaction between the two kinases and PDR6. By using LC-MS/MS, we also identified the PDR6 phosphorylation sites that were modified by the two kinases in vitro. Through the expression of the dephosphorylated variants of PDR6 in the mutant background, the action site S31 of OXI1 and the action sites S33 and S827 of AGC2-2 were found to have positive effects on the efflux activity of PDR6. In addition, T832, the action site of OXI1, may contribute to the stability of PDR6 on the plasma membrane.

plant biology↗

bioRxiv2020

Root water gates and not changes in root structure provide new insights into plant physiological responses and adaptations to drought, flooding and salinity

The influence of aquaporin (AQP) activity on plant water movement remains unclear, especially in plants subject to unfavorable conditions. We applied a multitiered approach at a range of plant scales to (i) characterize the resistances controlling water transport under drought, flooding and flooding plus salinity conditions; (ii) quantify the respective effects of AQP activity and xylem structure on root (Kroot), stem (Kstem) and leaf (Kleaf) conductances, and (iii) evaluate the impact of AQP-regulated transport capacity on gas exchange. We found that drought, flooding and flooding-salinity reduced Kroot and root AQP activity in Pinus taeda, whereas Kroot of the flood-tolerant Taxodium distichum did not decline under flooding. The extent of the AQP-control of transport efficiency varied among organs and species, ranging from 35%-55% in Kroot to 10%-30% in Kstem and Kleaf. In response to treatments, AQP-mediated inhibition of Kroot rather than changes in xylem acclimation controlled the fluctuations in Kroot. The reduction in stomatal conductance and its sensitivity to vapor pressure deficit were direct responses to decreased whole-plant conductance triggered by lower Kroot and larger resistance belowground. Our results provide new mechanistic and functional insights on plant hydraulics that are essential to quantifying the influences of future stress on ecosystem function.

developmental biology↗

bioRxiv2019

MicroRNA-222 regulates fluid shear stress-induced human nucleus pulposus cells degeneration through affecting c-Fos expression

Intervertebral disc degeneration (IVDD) is a chronic disease that correlates with the deterioration of the nucleus pulposus (NP) cells. However, the molecular mechanism of IVDD remains unclear. In this study, we investigated the function of microRNA-222 in IVDD and the potential molecular mechanism. NP cells treated with fluid shear stress (FSS) were used to simulate a model of IVDD in vitro. MicroRNA-222 was significantly downregulated in NP cells stimulated with FSS compared with that in unstimulated NP cells. Human NP cells were also treated with FSS to induce their degeneration. The mRNA and protein levels of C-FOS, MEK, phosphorylated MEK5 (pMEK5), ERK5, and pERK5 were evaluated with RT-PCR and western blotting, respectively. Enzyme-linked immunosorbent assays were used to investigate type II collagen and Aggrecan expression. NP cell proliferation was determined with the Cell Counting Kit-8. MicroRNA-222 was significantly downregulated in NP cells treated with FSS. The production of c-Fos and MEK5 were markedly reduced or increased in NP cells transfected with the has-microRNA-222 mimic or inhibitor, respectively, whether or not they were stimulated with FSS. The overexpression or inhibition of microRNA-222 markedly accelerated or suppressed the apoptosis of FSS-stimulated NP cells, respectively. In the NP cells, the overexpression or inhibition of microRNA-222 massively inhibited or strengthened Aggrecan and type II collagen expression. Together, our data indicated that c-Fos was a target of microRNA-222, and was negatively regulated by microRNA-222 in NP cells. Our findings also suggested that microRNA-222 is a possible therapeutic target for IVDD because it regulates c-Fos.

cell biology↗