Biology subjects

ZHANG, C.

Publications and source records attributed to ZHANG, C..

5 recordsLinked to original sources

bioRxiv2023

Circulating Microparticles: Optimization and Standardization of Isolation Protocols and Reassessment of Their Characteristics and Functions

Microparticles (MPs) are convenient for clinical diagnosis, and have functional roles in signal transduction. Although the importance of MPs is being increasingly recognized, the diversity of isolated protocols for MPs results in a heterogeneous population of their unknown origins, even expands to uncertain functions. Here we systematically studied the composition of MPs at different centrifugal speed intervals, and found that 3000g was a critical centrifugation speed in determining new MPs composition. The platelet-derived particles accounted for more than 80% under 3000g, while only about 20% in MPs obtained over 3000g. Furthermore, we found that the function of new MPs was significantly different from that of traditional ones, such as procoagulation activity, anti-inflammation and clinical diagnosis etc. Thus, our work optimized the method of MPs isolation, clarified some characteristics and physiological functions that should belong to platelets rather than MPs, which will derive new conceptual MPs for its composition and function.

cell biology↗

bioRxiv2022

BeEM: fast and faithful conversion of mmCIF format structure files to PDB format

Although mmCIF is the current official format for deposition of protein and nucleic acid structures to the Protein Data Bank (PDB) database, the legacy PDB format is still the primary supported format for many structural bioinformatics tools. Therefore, reliable software to convert mmCIF structure files to PDB files is needed. Unfortunately, existing conversion programs fail to correctly convert many mmCIF files, especially those with many atoms and/or long chain identifies. This study proposed BeEM, which converts any mmCIF format structure files to PDB format. BeEM conversion faithfully retains all atomic and chain information, including chain IDs with more than 2 characters, which are not supported by any existing mmCIF to PDB converters. The conversion speed of BeEM is at least ten times faster than existing converters such as MAXIT and Phenix. BeEM is available under the BSD licence at https://github.com/kad-ecoli/BeEM/.

bioinformatics↗

bioRxiv2022

US-align: Universal Structure Alignments of Proteins, Nucleic Acids, and Macromolecular Complexes

Structure comparison and alignment are of fundamental importance in structural biology studies. We developed the first universal platform, US-align, to uniformly align monomer and complex structures of different macromolecules (proteins, RNAs, and DNAs). The pipeline is built on a uniform TM-score objective function coupled with a heuristic alignment searching algorithm. Large-scale benchmarks demonstrated significant advantages of US-align over state-of-the-art methods in pairwise and multiple structure alignments of different molecules. Detailed analyses showed that the major advantage of US-align lies in the extensive optimization of the unified objective function powered by efficient heuristic search iterations, which significantly improve the accuracy and speed of the structural alignment process. Meanwhile, the universal protocol fusing different molecular and structural types helps facilitate the heterogeneous oligomer structure comparison and template-based protein-protein and protein-RNA/DNA docking.

bioinformatics↗

bioRxiv2021

A survey of Chinese pig farms and human healthcare isolates reveals separate human and animal MRSA populations

There has been increasing concern that the overuse of antibiotics in livestock farming is contributing to the burden of antimicrobial resistance in people. Farmed animals in Europe and North America, particularly pigs, provide a reservoir for livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA, ST398) found in people. This study was designed to investigate the contribution of MRSA from Chinese pig farms to human infection and carriage.A collection of 603 S. aureus were isolated from 55 pig farms and 4 hospitals (MRSA= 285, 198; MSSA= 50, 70) in central China, a high pig farming density area, during 2017-2018. CC9 MRSA accounting for 93% of all farm MRSA isolates, while no was found in hospitals. ST398 isolates were found on three farms (n = 23) and three hospitals (n = 12). None of the ST398 from this study belong to the livestock clade of the LA-MRSA commonly found in Europe and North America. The hospital ST398 MRSA isolates formed a clade that was clearly separate from the farm ST398 MRSA and MSSA isolates, and all possessed human immune evasion cluster genes which were absent from all the pig farm ST398 isolates. Despite the presence of high levels of MRSA found on Chinese pig farms we found no evidence of them spilling over to the human population. Nevertheless, the ST398 MRSA obtained from human samples appear to be part of a widely distributed lineage in China. And the new animal adapted ST398 lineage that emerged in China should also be alarmed. ImportanceWe disclosed the fact that although the high MRSA positive rate in Chinese hospitals and pig farms should be alarmed, they might be two separate issues. The new CC398 clades we identified highlight that the host adaption of the MRSA lineage is kept changing. These results suggest that continued surveillance of MRSA in livestock is necessary. We found that the pig farm MRSA isolates had unique antimicrobial resistance genes while most of the hospital MRSA isolates had human immune evasion cluster genes. These features could be used to distinguish the pig farm associated S. aureus in clinical laboratories. The policies of reducing antimicrobials use in livestock were implemented in China since 2020. Our study described the situation of MRSA populations in pig farms and hospitals in Central China before 2020, which provides a potential opportunity for future studies to evaluate the effects of the policies.

microbiology↗

bioRxiv2021

RTL8 promotes nuclear localization of UBQLN2 to subnuclear compartments associated with protein quality control

The brain expressed ubiquilins (UBQLNs) 1, 2 and 4 are a family of ubiquitin adaptor proteins that participate broadly in protein quality control (PQC) pathways, including the ubiquitin proteasome system (UPS). One family member, UBQLN2, has been implicated in numerous neurodegenerative diseases including ALS/FTD. UBQLN2 typically resides in the cytoplasm but in disease can translocate to the nucleus, as in Huntingtons disease where it promotes the clearance of mutant Huntingtin protein. How UBQLN2 translocates to the nucleus and clears aberrant nuclear proteins, however, is not well understood. In a mass spectrometry screen to discover UBQLN2 interactors, we identified a family of small (13 kDa), highly homologous uncharacterized proteins, RTL8, and confirmed the interaction between UBQLN2 and RTL8 both in vitro using recombinant proteins and in vivo using mouse brain tissue. Under endogenous and overexpressed conditions, RTL8 localizes to nucleoli. When co-expressed with UBQLN2, RTL8 promotes nuclear translocation of UBQLN2. UBQLN2 and RTL8 colocalize within ubiquitin-enriched subnuclear structures containing PQC components. The robust effect of RTL8 on the nuclear translocation and subnuclear localization of UBQLN2 does not extend to the other brain-expressed ubiquilins, UBQLN1 and UBQLN4. Moreover, compared to UBQLN1 and UBQLN4, UBQLN2 preferentially stabilizes RTL8 levels in human cell lines and in mouse brain, supporting functional heterogeneity among UBQLNs. As a novel UBQLN2 interactor that recruits UBQLN2 to specific nuclear compartments, RTL8 may regulate UBQLN2 function in nuclear protein quality control.

neuroscience↗