Ambient ionization mass spectrometry (AIMS) is both labor and time saving and has been proven to be useful for the rapid delineation of trace organic and biological compounds with minimal sample pretreatment. Herein, an analytical platform of probe sampling combined with a thermal desorption–electrospray ionization/mass spectrometry (TD-ESI/MS) and multivariate statistical analysis was developed to rapidly differentiate bacterial species based on the differences in their lipid profiles. For comparison, protein fingerprinting was also performed with matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) to distinguish these bacterial species. Ten bacterial species, including five Gram-negative and five Gram-positive bacteria, were cultured, and the lipids in the colonies were characterized with TD-ESI/MS. As sample pretreatment was unnecessary, the analysis of the lipids in a bacterial colony growing on a Petri dish was completed within 1 min. The TD-ESI/MS results were further performed by principal component analysis (PCA) and hierarchical cluster analysis (HCA) to assist the classification of the bacteria, and a low relative standard deviation (5.2%) of the total ion current was obtained from repeated analyses of the lipids in a single bacterial colony. The PCA and HCA results indicated that different bacterial species were successfully distinguished by the differences in their lipid profiles as validated by the differences in their protein profiles recorded from the MALDI-TOF analysis. In addition, real-time monitoring of the changes in the specific lipids of a colony with growth time was also achieved with probe sampling and TD-ESI/MS. The developed analytical platform is promising as a useful diagnostic tool by which to rapidly distinguish bacterial species in clinical practice.

Matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) mass spectrometry is a sensitive analytical tool for characterizing various biomolecules in biofluids. In this study, MALDI-TOF was used to characterize potential plasma biomarkers for distinguishing patients with major depressive disorder (MDD) from patients with schizophrenia and healthy controls. To avoid interference from albumin—the predominant protein in plasma—the plasma samples were pretreated using acid hydrolysis. The results obtained by MALDI-TOF were also validated by electrospray ionization-quadrupole time-of-flight (ESI-QTOF) mass spectrometry. The analytical results were further treated with principal component analysis (PCA), hierarchical clustering analysis (HCA), and receiver operating characteristic (ROC) curve analysis. The statistical analyses showed that MDD patients could be distinguished from schizophrenia patients and healthy controls by the lack of apolipoprotein C1 (Apo C1), which, in fact, was detected in healthy controls and schizophrenia patients. This protein is suggested to be a potential plasma biomarker for distinguishing MDD patients from healthy controls and schizophrenia patients. Since sample preparation for MALDI-TOF is very simple, high-throughput plasma apolipoprotein analysis for clinical purposes is feasible.

Typing Mycobacterium tuberculosis (MTB) isolates is important for identifying clusters and guiding infection control measures. Although whole-genome sequencing (WGS) and 24-loci mycobacterial interspersed repetitive units-variable-number tandem repeat (MIRU-VNTR) are widely used for molecular typing, they may not capture phenotypic or metabolic variation. Alternative approaches, such as mass spectrometric-based profiling, could provide complementary insights. A total of 247 clinical MTB isolates were analyzed by thermal desorption-electrospray ionization mass spectrometry (TD-ESI/MS). The resulting mass spectral profiles were evaluated using principal component analysis (PCA) and hierarchical clustering analysis (HCA). Results were compared with lineage classifications based on WGS and MIRU-VNTR to assess concordance. While WGS and MIRU-VNTR were highly concordant for lineage classification (98.8%; 244/247), TD-ESI/MS revealed diverse spectral profiles that did not align consistently with genetic lineages. However, HCA showed isolate-level clustering, including among genetically similar strains, suggesting that TD-ESI/MS may detect metabolic or lipidomic differences not captured by genome-based methods. Although TD-ESI/MS does not generate similar results from MTB molecular typing, it shows potential for identifying specific spectral signatures. The technique may be useful in future investigations into phenotypic diversity and other clinically relevant features not captured by genotyping alone.

A single-use, cost-effective, thin-film solid-phase microextraction (SPME) fiber was developed through a straightforward procedure. The extractant and substrate employed were bis(2-ethylhexyl) phosphate (BEHP) and poly(vinylidene difluoride) (PVDF) films, respectively. Angiotensin I and II served as the model analytes. The SPME fiber facilitated the extraction of these peptides from an aqueous solution, primarily via hydrophobic interactions and electrostatic attraction. Post-extraction, the peptide-enriched fibers were analyzed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI/MS) after applying α-cyano-4-hydroxycinnamic acid (CHCA) solution to the fiber. The study examined factors influencing detection and extraction efficiency, including CHCA solution composition, BEHP concentration, pH range, agitation rate, and extraction time. The method's application for peptide determination in urine samples was successfully demonstrated. Based on optimal conditions, the calibration curves for angiotensin I and II in urine samples demonstrated linearity across a concentration range of 0.10 to 100.00 nM. The detection limits for both peptides were determined to be 0.03 nM. The enhancement factors were calculated to be 85 for angiotensin I and 94 for angiotensin II, respectively. Integrating these single-use SPME fibers with MALDI/MS detection significantly simplifies peptide analysis in human urine samples.

This study aimed to evaluate the potential of Lonicera japonica Flos (LJF) as an alternative agent against Eimeria tenella (E. tenella) in chickens and to conduct phytochemical analysis to obtain compositional insights. Seventy-two one-day-old chickens were allocated to six groups and fed diets supplemented with LJF powder (LJFp) at three concentrations (LJFp-L, LJFp-M, and LJFp-H) or maduramicin (MDM) or two non-supplemented control diets, namely, an infected unmedicated control (IUC) and an uninfected unmedicated control (UUC). Dietary treatments were initiated at chick arrival (Day 0) and continued for 28 days. At 21 days of age, all groups except the UUC group were orally challenged with a field isolate of E. tenella (PT-Te003; 2.0 × 10⁴ oocysts/bird). Anticoccidial efficacy was assessed using the lesion score (LS), oocysts per gram of feces (OPG), relative body weight gain (rBWG), and anticoccidial index (ACI). The results demonstrated that all LJFp treatment groups had significantly reduced cecal OPG and LS (all LJFp treatments: p < 0.05 vs. IUC), indicating the effective suppression of E. tenella replication and intestinal damage. Regarding growth performance, the rBWG values of the LJFp-L and LJFp-M groups were the highest and comparable to those of the UUC group, showing no significant differences. In contrast, the LJFp-H and MDM groups exhibited significantly lower values (p < 0.05). Based on ACI evaluation, all LJFp-treated groups exhibited moderate to partial efficacy (LJFp-L > LJFp-M > LJFp-H), while MDM showed limited effectiveness. A gas chromatography–mass spectrometry (GC-MS) analysis of the LJFp ethanol extract revealed 15 essential oils, 10 organic acids, and three other compound classes, several of which have been associated with anticoccidial activity. Overall, the in vivo results suggest that LJF may exert potential anticoccidial effects against a field isolate of E. tenella. Phytochemical analysis provided preliminary compositional insights, and further studies are warranted to optimize extraction methods and evaluate efficacy at lower concentrations under additional in vitro and in vivo conditions. However, the current evidence remains insufficient to determine whether the field isolate exhibits reduced sensitivity to commercially available anticoccidial drugs, and additional studies are needed to clarify this issue.