The Expression Characteristics and Potential Functions of Heat Shock Factors in Diatom Phaeodactylum tricornutum

Heat shock transcription factor(HSF)are essential regulators of heat shock protein(HSP)gene expression in plants and algae,contributing to their resilience against biotic and abiotic stresses.However,the localization,structure,phylogenetic relationship,and characteristics of PtHSF genes in microalgae,especially in diatom Phaeodactylum tricornutum,remain largely unexplored.This study presents a comprehensive analysis of the PtHSF gene family in P.tricornutum.A genome-wide analysis identified 68 PtHSF genes,which were classified into two distinct subfamilies:traditional and untraditional.Motif and structure analyses revealed evidence of multiple duplication events within the PtHSF gene family.Expression profiling revealed diurnal patterns,with 34 genes being downregulated during the light period and upregulated during the dark period,while 19 genes exhibited the opposite pattern.These findings suggest that PtHSF genes may have specialized functions during the diurnal cycle and play a crucial role in maintaining cellular homeostasis in response to various stresses.Notably,PtHSF16,30,and 43 genes exhibited higher expression levels,suggesting their potential importance.This study provides a valuable foundation for future investigations into the specific functions of HSFs under different stress conditions and their regulatory mechanisms in P.tricornutum and other microalgae.

Protein Disulfide Isomerase and Its Potential Function on Endoplasmic Reticulum Quality Control in Diatom Phaeodactylum tricornutum

PDI is a molecular chaperone and plays an important role in Endoplasmic Reticulum quality control (ERQC).PDI participates in the refolding of the misfolded/unfolded proteins to maintain cellular homeostasis under differentstresses. However, bioinformatic characteristics and potential functions of PDIs in diatom Phaeodactylumtricornutum (Pt) are still unknown so far. Hence, the genome-wide characteristics of PtPDI proteins in P. tricornutumwere first studied via bioinformatic and transcriptomic methods. 42 PtPDI genes were identified from thegenome of P. tricornutum. The motif, protein structure, classification, number of introns, phylogenetic relationship,and the expression level of 42 PtPDI genes under the tunicamycin stress were analyzed. A pair of tandemduplicated genes (PtPDI15 and PtPDI18) was observed in P. tricornutum. The 42 PtPDIs with different genecharacteristics were divided into three independent clades, indicating different evolutional relationships and functionsof these PtPDIs. The 14 up-regulated PtPDI genes under the tunicamycin treatment might have a positiveeffect on the ER quality control of the unfolded/misfolded proteins, while the 7 down-regulated PtPDIs mightnegatively affect the ERQC. The characteristics of all 42 PtPDIs and their proposed working model here providea comprehensive understanding of the PtPDIs gene family. The differential expression of 21 PtPDIs will be usefulfor further functional study in the ERQC.

One-Step Preparation of Green Fabric for Continuous Antibacterial Applications

Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful development of a facile one-step method to fabricate a series of novel triclosan poly-dopamine polypropylene(TPP)composite scaffolds and thereby effectively improve the biocompatibility and long-term antibacterial properties of PP scaffolds.The antibacterial triclosan can effectively interact with dopamine during biocompatible polydopamine formation on the PP scaffold by one-step green fab-rication.Thanks to the sustained release of triclosan from the biocompatible polydopamine coating,a 5mm×5mm sample of TPP-coated scaffold made with a triclosan concentration of 8 mg-mL^(-1)(referredto herein as TPP-8)exhibited a continuous antibacterial effect against both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)for more than 15d,at maximum antibacterial volumes of 2 and 5mL,respectively.Our study establishes a new direction for facile long-term antibacterial studies for medical applications.