Biology subjects

Tan, Z. L.

Publications and source records attributed to Tan, Z. L..

6 recordsLinked to original sources

bioRxiv2026

Isolation and Characterisation of Hair Follicle-Derived Melanocytes

Melanocytes are unique population of cells which produce melanin pigment. However, the property of melanocytes from hair follicle and epidermis, particularly, their molecular signatures remained largely unknown. In this study, we investigated the properties of epidermis and hair follicle melanocytes by biochemical and molecular biological assays. We found that epidermal melanocytes are differentiated and mature form of hair follicle melanocytes, and they are potentially related. Irradiation with NB-UVB did not induce cell death of hair follicle melanocytes as observed in epidermal melanocytes, but activate hair follicle melanocytes, promote proliferation and migration. In situ study suggested that after UVB irradiation, root sheath of hair follicles, particularly proximity of interfollicular epidermis and hair bulb become darker, suggesting migration and maturation of hair follicle melanocytes after UVB irradiation, rather than cell death. This observation provides hints and evidence to the relationship between hair follicle and epidermal melanocytes, helps to explain the contradiction of melanocytes cell death after UVB irradiation and the use of UVB in treatment of vitiligo lesion, as well as the perifollicular repigmentation phenomenon observed in vitiligo lesion after NB-UVB phototherapy.

cell biology↗

bioRxiv2023

In vivo Stability and Biodistribution of Liposome Coated with SlpB from Levilactobacillus brevis

SlpB from Levilactobacillus brevis offers a solution to stabilise liposome in gastrointestinal tract, and to target intestinal APCs in Peyers patches, rendering it a powerful tool for oral delivery of drugs, and to yield the benefits provided by oral delivery. However, the stability of SlpB-coated liposome (SlpB-LP) and its distribution in tissues were not characterized. In this study, we have demonstrated that SlpB-coating could improve the stability of liposome in gastrointestinal tract, and facilitate specific uptake of liposome into Peyers patches, but not intestinal, nor intestinal mucosa. Furthermore, we have shown that uptake of SlpB-LP into Peyers patches enhanced bioavailability of drugs, which have resulted in 427.65-fold increase in bioavailability and at least 2.41-fold decrease in retention of fluorophore in liver where drug metabolism takes places, to a degree which approximate control group. In conclusion, this study shows that SlpB could increase stability of liposome in gastrointestinal tract, increase specific uptake of liposome into Peyers patches, and improve bioavailability. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/533723v1_ufig1.gif" ALT="Figure 1"> View larger version (69K): org.highwire.dtl.DTLVardef@ed508aorg.highwire.dtl.DTLVardef@42cef8org.highwire.dtl.DTLVardef@2219a9org.highwire.dtl.DTLVardef@c2e3dd_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2023

Identification of host-interacting domains of surface layer protein B from Levilactobacillus brevis and the evidence as glycoprotein

Surface layer proteins (Slps) can be found on the surface of some lactobacilli which involves in host-interaction and show immunomodulatory activity. Despite the capability of Slps to interact with C-type lectins on antigen presenting cells, present of sugar has not been confirmed except for Lentilactobacillus kefiri. In this study, we investigated the presence of sugar moiety in the structure of SlpB from Levilactobacillus brevis, and its involvement in interaction with DC-SIGN of dendritic cells. 4 fragments of sugar containing fragments were identified in SlpB, and the involvement of sugar in DC-SIGN interaction was confirmed by competitive assay against hexoses. The sequences of these fragments were identified based on the mass obtained from mass spectrometry, and the result has confirmed that these fragments were from carbohydrate binding motifs of SlpB. Analysing the binding affinities of these fragments with surface resonance plasmon analysis suggested that 2 fragments possess higher binding affinity compared to the remaining fragments, and the sum of binding affinities of these fragments was approximate the affinity of intact SlpB.

biochemistry↗

bioRxiv2023

Hydrogel Microdroplet-Based Digital Quantitative Polymerase Chain Reaction

Droplet digital PCR (ddPCR) is accurate in nucleic acid quantification owing to its linearity and high sensitivity. Amplification of nucleic acid in droplets, however, is limited by the stability of droplets against thermal cycling. While the use of fluorinated oil or supplementation of surfactant could improve the stability of droplets, this process has also greatly increased the cost of ddPCR and limited post-PCR analysis. Here, we report a novel method known as gel capsule-based digital PCR (gc-dPCR) which includes method to prepare hydrogel capsules encapsulating PCR reaction mix, conducting PCR reaction, and readout by either qPCR system or fluorescence microplate reader. We have compared our method to existing methods, i.e., quantitative PCR or vortex ddPCR. Our approach results in higher fluorescence intensity compared to ddPCR suggesting higher sensitivity of the system. As hydrogel capsules are more stable than droplets in fluorinated oil throughout thermal cycling, all partitions can be quantified, thus preventing loss of information from low-concentration samples. Our approach should extend to all droplet-based PCR methods. Generally, our approach has greatly improved ddPCR by increasing droplets stability and sensitivity, and reducing the cost of ddPCR, which help to remove the barrier of ddPCR in settings with limited resources. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=62 SRC="FIGDIR/small/534823v2_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@15a291eorg.highwire.dtl.DTLVardef@4189e2org.highwire.dtl.DTLVardef@c35fd8org.highwire.dtl.DTLVardef@c972d0_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2022

A novel attention-based peptide language model for dipeptidyl peptidase-IV inhibitory peptides mining

Mining of anti-diabetic dipeptidyl peptidase IV (DPP-IV) inhibitory peptides (DPP-IV-IPs) is currently a costly and laborious process. Due to the absence of rational peptide design rules, it relies on cumbersome screening of unknown enzyme hydrolysates. Here, we present an enhanced deep learning (DL) model called BERT-DPPIV, specifically designed to classify DPP-IV-IPs and exploring their design rules to discover potent candidates. The end-to-end model utilizes a fine-tuned bidirectional encoder representations (BERT) architecture to extract structural/functional information from input peptides and accurately identify DPP-IV-Ips from input peptides. Experimental results in benchmark dataset showed BERT-DPPIV yielded state-of-the-art accuracy of 0.894, surpassing the 0.797 obtained by sequence-feature model. Furthermore, we leverage the attention mechanism to uncover that our model could recognize restriction enzyme cutting site and specific residues that contribute to the inhibition of DPP-IV. Moreover, guided by BERT-DPPIV, proposed design rules of DPP-IV inhibitory tripeptides and pentapeptides were validated and they can be used to screen potent DPP-IV-IPs.

bioinformatics↗

bioRxiv2019

Microbial microdroplet culture system (MMC): an integrated platform for automated, high-throughput microbial cultivation and adaptive evolution

Conventional microbial cell cultivation techniques are typically labor intensive, low throughput, and poor parallelization, rendering them inefficient. The development of automated, modular microbial cell micro-cultivation systems, particularly those employing droplet microfluidics, has gained attention for their high-throughput, parallel and highly efficient cultivation capabilities. Here, we report the development of a microbial microdroplet culture system (MMC), which is an integrated platform for automated, high-throughput cultivation and adaptive evolution of microorganisms. We demonstrated that the MMC yielded both accurate and reproducible results for the manipulation and detection of droplets. The superior performance of MMC for microbial cell cultivation was validated by comparing the growth curves of six microbial strains grown in MMC, conventional shake flasks or well plates. The highest incipient growth rate for all six microbial cell lines was achieved using MMC. We also conducted an 18-day process of adaptive evolution of a methanol-essential Escherichia coli strain in MMC and obtained two strains exhibiting higher growth rates compared with the parent strain. Our study demonstrates the power of MMC to provide an efficient and reliable approach for automated, high-throughput microbial cultivation and adaptive evolution.

bioengineering↗