Progress In Microbes & Molecular Biology

Molecular Mechanisms of Melanogenesis in Hyperpigmentation: From Signaling Pathways to Nanocarrier-Based Therapeutic Strategies

2026-09-07T11:51:57+08:00

Hyperpigmentation remains a complex dermatological challenge, often resistant to conventional topical therapies due to the skin’s inherent barrier function and the chemical instability of active depigmenting agents. Traditional formulations of depigmentation agents frequently suffer from poor dermal penetration and dose-dependent toxicity, leading to localized irritation and high relapse rates. This review highlights the transformative role of cosmeceutical nanotechnology in overcoming these limitations through advanced delivery systems, including lipid-based nanocarriers, polymeric nanoparticles, and microbiota-derived metabolite platforms. These nanosystems enhance the stability, controlled release, and targeted delivery of active compounds to melanocytes within the basal epidermis while modulating key molecular pathways involved in melanogenesis. Their mechanisms include inhibition of tyrosinase activity through active-site copper chelation, suppression of microphthalmia-associated transcription factor (MITF) signaling, and disruption of melanosome transport and transfer to keratinocytes. Emerging microbiota-based approaches further contribute by regulating oxidative stress, inflammation, and pigmentation while helping maintain skin homeostasis. Experimental and clinical evidence demonstrates that nanocosmeceutical formulations significantly improve depigmenting efficacy. Despite these advantages, challenges remain regarding nanotoxicity, long-term safety, large-scale manufacturing, and the lack of harmonized regulatory frameworks governing nanocosmeceuticals. As demand for effective and minimally invasive skincare continues to grow, nanotechnology provides a promising strategy for developing safer, more stable, and highly bioavailable therapies for hyperpigmentation. Continued research, standardized safety evaluation, and clearer regulatory guidelines are essential to facilitate the successful clinical translation and commercialization of nanotechnology-based depigmenting formulations.

Microbial Siderophores in Sustainable Agriculture: Molecular Insights, Smart Delivery Systems, and Biotechnological Applications

2026-05-04T17:54:53+08:00

Microbial siderophores are low-molecular-weight compounds with a strong affinity for ferric (FSe³⁺) ions. They play a pivotal role in plant-microbial interactions by enhancing iron bioavailability to plants, primarily through the chelation and mobilization of iron under iron-limited conditions. Their versatile and multifunctional nature has positioned them as promising agents for sustainable and eco-friendly agriculture. However, the practical application of siderophore-based systems is constrained by challenges related to stability, bioavailability, environmental degradation, and large-scale production. This review examines recent advancements in siderophore-mediated agricultural practices and applications, with a focus on formulation strategies and delivery systems, including seed coatings, foliar sprays, and nanoparticle-based encapsulation approaches. The review further highlights key technological innovations integrating nanotechnology, microbiology, and artificial intelligence (AI) for precision agriculture. Particular emphasis is placed on controlled-release systems, production scalability, and field-level applicability. Existing knowledge gaps, particularly in large-scale production and commercialization, are discussed alongside future prospects involving synthetic biology and engineered microbial systems. Siderophore-based technologies represent a transformative approach toward enhancing soil health, crop productivity, and sustainable bioeconomy development.

Early colonization by Enterobacteriaceae in the developing gut microbiota of preterm infants: A culture-based insight

2026-05-15T15:49:24+08:00

The gut microbiome plays a significant role in human health and disease pathogenesis. In preterm infants, gut dysbiosis often results in early dominance of opportunistic pathogens, particularly members of the Enterobacteriaceae family. Enterobacteriaceae can serve as potential reservoirs of opportunistic pathogens, antibiotic-resistance determinants and may contribute to major neonatal morbidities, including necrotizing enterocolitis (NEC) and late-onset sepsis (LOS). This study aims to isolate and identify Enterobacteriaceae, as well as to explore the diversity of isolated Klebsiella pneumoniae from meconium/early stool samples of preterm infants collected from a neonatal intensive care unit (NICU) in Johor Bahru, Malaysia. A combination of culture-based isolation technique, phenotypic and genotypic identification methods was used to identify the culturable Enterobacteriaceae in the gut of preterm infants. Three main bacterial families were successfully isolated and identified from the stool samples of preterm infants, which include Enterobacteriaceae, 46% (76/166 isolates), Staphylococcaceae, 22% (37/166), Enterococcaceae, 22% (37/166) and others, 10% (16/166). It was clear that Enterobacteriaceae was one of the predominant bacterial groups during the early gut colonization in preterm infants, making up to 46% of all isolates. Within the Enterobacteriaceae family, K. pneumoniae, 74% (56/76 isolates) dominates, followed by Escherichia coli, 15% (11/76), Klebsiella aerogenes, 9% (7/76), Citrobacter europaeus, 1% (1/76), and Citrobacter freundii, 1% (1/76). The high number of Enterobacteriaceae isolates, particularly K. pneumoniae, followed by E. coli are concerning as these bacterial species are often associated with hospital-acquired infections in the NICU. Our findings provide insight into the early gut colonization patterns of culturable gut bacteria in preterm infants. It highlights the importance of continuous microbiological monitoring and infection control measures within the NICU to mitigate potential Enterobacteriaceae-associated infections.

Phylogenomics, antimicrobial resistance, and mobile genetic elements in clinical Clostridioides difficile isolates from Hong Kong, China

2026-08-07T16:58:19+08:00

Whole-genome sequencing enables high-resolution characterisation of the evolutionary and accessory-genome diversity of Clostridioides difficile beyond conventional sequence typing. We analysed 118 clinical C. difficile genomes from Hong Kong using recombination-filtered phylogenomics, pangenome analysis, antimicrobial-resistance and virulence screening, mobile-element context analysis and functional annotation. The population comprised 24 sequence types and formed distinct phylogenetic clusters that were broadly consistent with multilocus sequence typing assignments. Pangenome analysis identified 9,140 gene clusters and supported an open pangenome structure, indicating ongoing gene acquisition and loss within the population. Accessory-genome divergence increased with core-genome SNP distance (Spearman's ρ = 0.437, p < 1 × 10^-5), although some closely related isolates retained substantial differences in gene content, suggesting recent accessory-genome turnover. Antimicrobial resistance determinants showed stronger associations with mobile genetic elements (MGE) than with virulence-associated loci. In particular, erm(B), AAC/APH-family genes and tet(M) were frequently detected and commonly linked to insertion-sequence- or transposon-associated contexts, whereas major toxin loci showed limited evidence of local mobility. Functional annotation revealed broadly conserved functional profiles dominated by transcription-, metabolism-, and signal transduction-related categories, alongside significant sequence type-associated variation in KEGG pathway composition (PERMANOVA R² = 0.434, p = 0.001), with ST54 forming a distinct functional cluster. Collectively, these findings demonstrate that this Hong Kong C. difficile population is structured by stable evolutionary lineages while maintaining extensive accessory-genome diversity, and highlight the prominent role of MGE in shaping antimicrobial-resistance architecture relative to the largely conserved virulence repertoire.