TEMPERATURE-DEPENDENT ANTIMICROBIAL ELICITATION IN ENVIRONMENTAL BACTERIA CO-CULTURED WITH ENTEROCOCCUS FAECALIS IN THE PRESENCE OF AMPICILLIN/TETRACYCLINE

Sunday Stephen Abi — Tue, 20 Jan 2026 00:00:00 +0000

Research Objectives: This study investigated whether co-culturing environmental bacterial isolates against Enterococcus faecalis (NTUCC 687) in the presence of ampicillin or tetracycline could elicit antimicrobial production, and whether this response was temperature-dependent.

Methodology: A total of 96 environmental bacterial isolates (arrayed in a 96-well plate) collected from built and natural surfaces around NTU Clifton campus were co-cultured against an Enterococcus faecalis lawn using an in-house stamping assay on UTI ChromoSelect agar. Plates were incubated at 25°C, 30°C, 37°C, and 42°C for 24–72 hours. For elicitation, UTI agar was fortified separately with ampicillin (0.05 µg/mL) or tetracycline (0.05 µg/mL). These low (sub-inhibitory) concentrations were used as stressors to probe signalling-associated induction of antimicrobial activity rather than direct growth inhibition. Antimicrobial activity was recorded as categorical zones of inhibition, classified as small (+), medium (++), or large (+++).

Findings: Tetracycline elicited a higher frequency of large (+++) zones of inhibition than ampicillin, peaking at 30°C (12 isolates, 12.5%), followed by 42°C (9 isolates, 9.4%), 25°C (5 isolates, 5.2%), and 37°C (3 isolates, 3.1%). In contrast, ampicillin produced only two large zones (2.1%), both observed at 25°C. These patterns indicate that antimicrobial elicitation was modulated by both antibiotic stressor type and incubation temperature within the co-culture assay.

Research Outcomes and Future Scope: These findings support co-culture-based elicitation as a practical strategy for uncovering latent antimicrobial potential in environmental bacteria and highlight temperature as a key modulator of expression. Future work should identify the active producers and compounds involved, investigate underlying molecular mechanisms, and assess scalability for antimicrobial discovery.

THE ROLE OF INCOME IN THE PSYCHOSOCIAL HEALTH OF INDIVIDUALS EXPERIENCING POVERTY

Wed, 28 Jan 2026 00:00:00 +0000

Objective: Evaluate associations between social discrimination, self-stigma, social support and affect in a sample of Portuguese people living in poverty and analyze possible differences in these psychosocial variables between poor and very poor individuals. Method: This is a cross-sectional study involving 357 individuals aged between 18 and 70 (M =34.51; DV =14.59). The instruments used were Paradox of Self-Stigma, Multidimensional Scale of Perceived Social Support, Portuguese Everyday Discrimination Scale and Reduced Version of the Portuguese Positive and Negative Affect Scale. Results: The overall analysis revealed medium levels of social discrimination and negative affect, as well as high levels of self-stigma, perceived social support, and positive affect. Compared to the low-income group, the very low-income group reported more social discrimination and self-stigma, and lower perceived social support and positive affect. Negative affect perceived social support and salary predicted positive affect, while age, schooling, household, social discrimination and positive affect. Conclusions: Poverty was positively associated with social discrimination and self-stigma, and level of social support was a moderating variable in this association. Compared to low-income individuals, participants with very low income experienced significantly more social discrimination, self-stigma, and negative affect, suggesting a cumulative vulnerability effect of poverty on these indicators. Implementing public policies to include these populations is fundamental to combating vulnerability and reducing the adversities faced by people in situations of social vulnerability in Portugal.

LIFE: International Journal of Health and Life-Sciences

TEMPERATURE-DEPENDENT ANTIMICROBIAL ELICITATION IN ENVIRONMENTAL BACTERIA CO-CULTURED WITH ENTEROCOCCUS FAECALIS IN THE PRESENCE OF AMPICILLIN/TETRACYCLINE

THE ROLE OF INCOME IN THE PSYCHOSOCIAL HEALTH OF INDIVIDUALS EXPERIENCING POVERTY