Touchkanin Jongjitvimol

Hydroquinine, a cinchona alkaloid, has demonstrated antibacterial activity against multidrug-resistant pathogens, with previous transcriptomic data implicating the arginine deiminase (ADI) pathway. However, its potential molecular target engagement remains to be fully characterized. This study aimed to investigate potential molecular targets of hydroquinine within the ADI pathway utilizing an Escherichia coli BL21 heterologous expression model. We integrated computational molecular docking as a hypothesis-generating tool, in silico-guided site-directed mutagenesis, and continuous broth microdilution growth kinetics profiling. Phenotypic profiling of the ADI-pathway transformants revealed that heterologous expression of the arginine/ornithine antiporter (AOA, encoded by arcD) was associated with growth tolerance under sub-inhibitory hydroquinine pressure. Serving strictly to nominate candidate binding residues, molecular docking predicted that the quinoline and quinuclidine moieties of hydroquinine may interact with residues Trp301 and Glu150 within the predicted AOA binding region. Consistent with these computational predictions, site-directed mutagenesis supported the contribution of these residues to the observed hydroquinine-associated phenotype. E. coli BL21 variants harboring the W301V and E150I arcD mutations lost the observed growth tolerance and exhibited significantly reduced maximum specific growth rates under sub-inhibitory hydroquinine stress. Furthermore, baseline growth defects in untreated mutants indicated potential fitness costs associated with these substitutions. In conclusion, this study provides preliminary insights into AOA as a potential target within a surrogate heterologous host, highlighting bacterial transport systems as candidate targets for future investigation of cinchona alkaloid-based antibacterial development.

Carbapenem resistance in Pseudomonas aeruginosa is frequently mediated by the mutational inactivation or complete loss of the oprD porin gene. However, extreme genetic polymorphism within oprD limits traditional PCR amplification, a bottleneck for molecular surveillance. This study aimed to design and validate a novel quantitative PCR (qPCR) primer set flanking the 5′ and 3′ untranslated regions to reliably amplify the complete oprD cassettes across divergent clinical isolates. The assay demonstrated optimal amplification at 54 °C and an analytical limit of detection (LoD) between 10⁻⁴ and 10⁻⁵ ng of genomic DNA mass. This assay successfully matched 94.09% (1608/1709) of globally distributed P. aeruginosa strains via in silico BLASTn analysis. In a blinded validation cohort of 100 clinical isolates (50 P. aeruginosa and 50 non-P. aeruginosa controls), the qPCR assay achieved 100.0% analytical specificity without cross-reactivity. Among the 50 P. aeruginosa isolates including 40 carbapenem-resistant (CRPA) and 10 carbapenem-susceptible (CSPA), the qPCR assay exhibited 96.0% sensitivity, successfully amplifying oprD cassettes in 95.0% (38/40) of CRPA and 100.0% (10/10) of CSPA strains without phenotypic bias (p > 0.9999). Notably, when combined with sequencing, the two qPCR-negative CRPA isolates were confirmed to harbor true biological oprD deletions. This optimized assay provides a robust molecular surveillance tool for detecting oprD cassettes to facilitate the epidemiological genetic characterization in both CRPA and CSPA isolates.

Background/Objectives: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a WHO critical-priority pathogen, and variations in the outer membrane porin CarO are one mechanism implicated in carbapenem resistance. No prior study has characterized carO mutation patterns among A. baumannii in Tak, Thailand. This study aimed to characterize carO mutation patterns in clinical isolates, evaluate their association with CRAB, reconstruct phylogeny, and predict the structural consequences of CarO representatives relative to a crystallographic reference structure (PDB 4RL9). Seventy-seven A. baumannii isolates were recovered from Mae Sot Hospital, and re-confirmed by PCR based on the presence of bla_OXA-51-like gene. Results: The carO gene was sequenced and mutations compared between CRAB and carbapenem-susceptible (CSAB) isolates. Of the 77 isolates, 70 yielded successfully carO sequence data by next-generation sequencing (NGS), including 64 CRAB (91.43%) and 6 CSAB isolates. Two overlapping mutation clusters were significantly associated among CRAB isolates (73.44% and 75.00%; p = 0.0008 and p = 0.0006) and were absent from all 6 CSAB isolates (8.57%). Phylogenetic analysis resolved 3 clinical lineages, with variant III predominating. AlphaFold2 models predicted structural divergence among CarO variants with the single variant IV isolate showing the most extensive predicted remodeling of the CarO barrel. Conclusions: carO mutation was strongly associated with carbapenem resistance in this Thai cohort. However, these findings do not establish a direct causal role of carO mutation in carbapenem resistance. Predicted structures were consistent with potential alterations of porin function. These findings provide a regional characterization of carO-mediated resistance and support further functional validation of CarO as a resistance marker.

Pinwheel Jasmine (Tabernaemontana divaricata L.; Apocynaceae) is widely distributed across South Asia, Thailand, and southern China and exhibits substantial morphological variation. This variability has resulted in persistent taxonomic confusion, particularly in Thailand, where distinguishing among phenotypic forms and related taxa remains challenging. Accurate taxonomic delimitation is essential for botanical classification, horticultural applications, conservation, and the reliable identification of plant resources. This study examined the taxonomic status of Pinwheel Jasmine in Thailand using numerical taxonomic approaches, including cluster and discriminant analyses. A total of 40 morphological characters (20 quantitative and 20 qualitative) were assessed across 210 operational taxonomic units (OTUs) representing seven phenotypes. Both analyses consistently resolved the OTUs into two distinct groups: (1) T. divaricata ‘Ceylon Jasmine’ (Phud Supachok) and (2) other Pinwheel Jasmine forms. Five quantitative characters were identified as the most diagnostic: lamina length (LML), lamina width (LMW), corolla lobe length (CLL), distance from the corolla tube base to stamen attachment (DCS), and style length (STL). These traits exhibited exceptionally high F-values in K-means cluster analysis (404.11, 432.90, 327.54, 530.04, and 181.02, respectively; p<0.01), indicating strong discriminatory power. The results demonstrate that Phud Supachok is consistently and clearly morphologically distinct from other Pinwheel Jasmine forms. However, because this study is based solely on phenetic data, additional molecular evidence is required before definitive taxonomic conclusions can be made. Integrative studies combining molecular and morphological data are recommended to refine species delimitation within Tabernaemontana.

In this study, the genetic diversity and evolutionary relationship among 65 Thai rice varieties were classified by the neighbor‐joining (NJ) analysis of DNA sequences, amplified by three cpDNA barcoding markers, namely, mat K , rbc L, and trn H -psb A. Based on DNA sequencing analyses, all studied rice varieties were incorporated with 20 plant accessions by comparison with the rice reference genome available on GenBank. These accessions were categorized into two groups of an ingroup (belonging to 17 accessions of Oryza genus). The findings revealed that the highest species resolution (100%) was achieved by using the mat K gene individually and combination of the mat K and rbc L genes. These markers proved highly effective in distinguishing landrace rice varieties from the outgroup (reference species of rice and grasses), with bootstrap support values ranging from 25% to 100%. Meanwhile, the classification of landrace rice varieties was successfully accomplished using the rbc L gene. However, it was unable to distinguish between the ingroup and outgroup. Additionally, the trn H -psb A marker exhibited a limited effectiveness in distinguishing native rice varieties from either the ingroup or outgroup. In combination with two or three markers, only the combination of mat K and rbc L genes exhibited the capability to distinguish all rice species from grass. However, combining either the mat K or rbc L gene with the trn H -psb A gene trended to enhance the efficacy in classifying native rice varieties. These findings, based on the genetic distance values obtained through various DNA markers using the Kimura two‐parameter model, were proved that the studied Thai rice varieties belong to the Oryza sativa L. species.

Background: Oral health significantly affects the overall well-being of the elderly, influencing nutrition, communication, and quality of life. Poor oral hygiene can cause infections and dental issues. In Thailand, promoting oral hygiene among the aging population remains a pressing and ongoing public health challenge. Design and methods: This study explores the factors influencing oral health care behaviors among elderly individuals at the Phitsanulok Health Center (Buddhachinaraj Hospital) as a case study of lower Northern Thailand. A total of 365 elderly participants were surveyed using a structured questionnaire. Results: Multiple regression analysis showed that general employment (β = −0.227, p < 0.001), business (β = −0.300, p < 0.001), and government service (β = −0.205, p < 0.001) were negative predictors of oral health care behaviors. In contrast, enabling factors (β = 0.204, p < 0.001), average monthly income (β = 0.200, p < 0.001), and supporting factors (β = 0.142, p = 0.005) had positive effects. These factors together explained 20.02% of the variation in behaviors ( p < 0.001), with enabling factors having the strongest influence. Conclusions: This study emphasizes the importance of financial security, access to dental care, and social support in maintaining oral health among the elderly. Enhancing affordable dental services is crucial for low-income seniors. The findings suggest further research into factors influencing elderly oral health and strategies to improve care access. Recommendations include reducing dental costs, creating family-centered health initiatives, involving families in oral hygiene, and enacting policies to support low-income elderly individuals.