Biology subjects

Ma, x.

Publications and source records attributed to Ma, x..

3 recordsLinked to original sources

bioRxiv2026

Health-associated gut bacteriocins target TLR4 to suppress intestinal inflammation

The human microbiome maintains host immune homeostasis by secreting bioactive metabolites. However, extending beyond well-characterized metabolites, the functions of most microbiome-encoded peptides remain poorly defined. In this study, we developed a multi-cohort metagenomic framework to profile protective class II bacteriocins--unmodified, ribosomally synthesized peptides--that are enriched in healthy individuals but depleted in patients with inflammatory bowel disease (IBD). We have designated these health-associated bacteriocins as gutcins. Two gutcins, which lack canonical antimicrobial activity, potently attenuate intestinal inflammation in murine models. Cryo-electron microscopy (cryo-EM) reveals that one gutcin, named gutcin 03, directly engages the C-terminus of TLR4, blocking its dimerization and downstream inflammatory signaling. Guided by this structural interface, we generated truncated variants with enhanced potency, demonstrating the amenability of these simple peptides to rational optimization. Collectively, our findings reposition class II bacteriocins from antimicrobial agents to endogenous immunomodulatory effectors and establish a structural and mechanistic foundation for their development as next-generation therapeutics for inflammatory intestinal disorders.

microbiology↗

bioRxiv2023

Molecular cloning and characterization of an AP2/ERF protein gene in cotton (Gossypium hirsutum L.)

Upland cotton (Gossypium hirsutum L.) is one of the most economically important crops worldwide due to the significant source of natural fiber, feed, oil and biofuel products. Cottonseed can also serve as an excellent source of edible protein and oil. However,the presence of gossypol in pigment gland has limited it utilization In the past few decades, some progress has been made in the understanding molecular mechanism of the formation of the pigment gland. However, little is known about the specific mechanism of pigment gland formation in cotton. In this study, the cDNA sequence of a ethylene transcription factor gene, designated GhERF105a, was cloned from upland cotton CCRI12. Sequence alignment revealed that GhERF105a gene contained a typical AP2/ERF domain of 61 amino acids, and belonged to the ERF subgroup of the ERF supfamily. It was highly expressed in the leaves and stems of glanded plants but had substantially lower expression of the glandless plants. GhERF105a, localized to the nucleus, could bind to GCC-box and DRE. Some development, phytohormone and stress related cis-elements were enriched in the promoters of GhERF105a/d. Split ubiquitin assays in yeast and BiFC experiments showed extensive interactions between GhERF105a and Gh_A07G1044. In addition, GhERF105a was highly similar with GhERF105d in the gene length, molecular weight, protein molecule, gene structure and expression pattern. The overall results suggested that GhERF105a might participate in the pigment gland formation and stree-response processes.

bioengineering↗

bioRxiv2020

DNA Methylation Reprogramming during Sex Determination and Transition in Zebrafish

It is a mystery about sex determination and sexual plasticity in species without sex chromosomes. DNA methylation is a prevalent epigenetic modification in vertebrates, which has been shown to involve in the regulation of gene expression and embryo development. However, it remains unclear about how DNA methylation regulates sexual development. To elucidate it, we used zebrafish to investigate DNA methylation reprogramming during juvenile germ cell development and adult female-to-male sex transition. We revealed that primordial germ cells (PGCs) undergo significant DNA methylation reprogramming during germline development and set to an oocyte/ovary-like pattern at 9 days post fertilization (9 dpf). When blocking DNMTs activity in juveniles after 9 dpf, the zebrafish preferably develops into females. We also show that Tet3 involves in PGC development. Notably, we find that DNA methylome reprogramming during adult zebrafish sex transition is similar to the reprogramming during the sex differentiation from 9 dpf PGCs to sperm. Furthermore, inhibiting DNMTs activity can prevent the female-to-male sex transition, suggesting that methylation reprogramming is required for zebrafish sex transition. In summary, DNA methylation plays important roles in zebrafish germline development and sexual plasticity.

developmental biology↗