To elucidate the photosynthetic-physiological responses of the locally isolated green alga Chlorella sp. to short-term interactive stress from acid-rain-driven water acidification and ultraviolet radiation (UVR) in the Trang River basin (southern Thailand), we simulated three pH gradients (7.2, 5.5, 4.7) under two pre-culture light regimes (low light: 60 μmol·m−2·s−1; medium-to-high light: 180 μmol·m−2·s−1). Algal growth, cell size, pigment composition, and chlorophyll-fluorescence-derived photosynthetic parameters were determined after 24 h acid exposure, followed by 1 h of visible-light (P) or PAB (visible-light + UVA + UVB) radiation treatment. Mild acidification (pH 5.5) significantly promoted the specific growth rate under medium-to-high light, whereas moderate acidification (pH 4.7) caused net population decline with negative growth rates. Pigment contents were mainly regulated by pre-culture light intensity rather than pH. Three-way ANOVA demonstrated that radiation treatment exerted significant main effects on effective quantum yield (Yield), maximum relative electron-transport rate (rETRmax), and light-utilization efficiency (α); pre-culture light intensity significantly affected Yield, and its interaction with radiation significantly affected α, whereas pH showed no significant main effect on rETRmax or α. PAB radiation strongly suppressed photosynthetic performance across all pH treatments. Notably, algae pre-cultured under low light exhibited substantially higher UVR-induced inhibition of effective quantum yield (Yield), especially at pH 4.7, indicating that the light intensity during pre-cultivation modulated algal vulnerability to co-stress of acidification and UVR. Although Chlorella sp. tolerates short-term mild acid stress, low-light-pre-cultured cells become more susceptible to UVR damage under moderate acidification (pH 4.7). These findings improve our understanding of how phytoplankton respond to multiple co-occurring environmental stressors in tropical acid-rain-sensitive freshwater watersheds.
Edible mushrooms are well known for their high nutritional value as they represent a source of glucans, bioactive peptides, vitamins, phenolic and indole compounds, and mineral elements. Despite their seasonal nature, there is hardly any evidence of their traditional preservation through lactic acid fermentation. However, their chemical composition allows the development of lactic acid bacteria. Indeed, lactic acid fermentation of mushrooms has been performed, either spontaneous or using a defined starter culture, resulting in products with very interesting and acceptable sensorial qualities. In addition, lactic acid fermentation may enrich mushrooms with bioactive compounds, increasing their nutritional value. The aim of the present article was to collect and critically discuss the technical details of mushroom lactic acid fermentation, the fate of bioactive compounds, and the associated health benefits, and ultimately to highlight the great potential of mushrooms as a substrate for lactic acid fermentation.
As the search for novel natural therapeutics intensifies, Garcinia cambogia (Gc) emerges as a powerhouse of phytochemical constituents, capable of inhibiting tumor growth. Thus, we aimed to evaluate the phytochemical screening and biological activity of the aqueous ethanolic extract of Gc fruit using HPLC, LC-MS, and GC-MS to identify natural phytochemical constituents. The antimicrobial activity of Garcinia fruit extract (GFE) was evaluated against methicillin-resistant Staphylococcus aureus and Enterococcus faecalis as Gram-positive bacteria, Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria, and Malassezia furfur and Candida albicans as fungi. HPLC revealed that GFE contained 14 polyphenol compounds, the LC-MS revealed the presence of fifty-six compounds at the positive ionization mode and forty-seven compounds at the negative mode; however, thirty-six compounds were detected using GC-MS. GFE exhibited the strongest inhibitory effects against E. faecalis, with a minimum inhibitory concentration (MIC) of 15.36 mg/mL. Where the inhibition zone diameters were 24.7, 21.7, 21.7, 21.3, and 20.7 mm for E. faecalis, S. aureus, P. aeruginosa, M. furfur, and E. coli, respectively, at the concentration of 500 mg/mL of GFE. In contrast, GFE exhibited no antimicrobial activity against Candida albicans. Furthermore, GFE was screened against three cancer cell lines, including breast cancer (MCF-7), colon cancer (HCT-116), and liver cancer (HepG2), and demonstrated in vitro cytotoxic activity, with IC50 values of 31.7, 49.87, and 48.99 μg/mL for MCF-7, HCT-116, and HepG2, respectively. These findings indicate that GFE is a promising natural antimicrobial agent, while its in vitro cytotoxic activity warrants further investigation.
Multiplex molecular testing has expanded respiratory pathogen detection, but contemporary data from the Gulf region remain limited. This retrospective observational study characterized respiratory pathogen detection and co-occurrence patterns and evaluated agreement between multiplex PCR and conventional respiratory culture among adults hospitalized with community-acquired pneumonia in Dubai, United Arab Emirates, between January 2022 and January 2025. Among 278 patients, at least one PCR target was detected in 232 (83.5%; 95% CI 78.6–87.4); 126 (45.3%; 95% CI 39.6–51.2) had single-organism detection, 106 (38.1%; 95% CI 32.6–44.0) had multiple-organism detection, and 46 (16.5%; 95% CI 12.6–21.4) had no target detected. The most frequently detected organisms were Haemophilus influenzae (29.5%), Streptococcus pneumoniae (25.2%), human rhinovirus (16.9%), Legionella pneumophila (15.8%), and influenza A virus (11.9%). Among 242 patients with respiratory culture available, shared bacterial targets were detected by both methods in 12 patients, by PCR alone in 156, by culture alone in two, and by neither method in 72. Positive percent agreement was 85.7%, negative percent agreement was 31.6%, overall agreement was 34.7%, and Cohen’s κ was 0.027. Multiplex PCR demonstrated a high molecular detection yield and revealed frequent, heterogeneous multiple-organism detection patterns. Molecular findings should be interpreted alongside clinical assessment and conventional culture.
Bacteriocin research has traditionally emphasised the organisms that produce inhibitory peptides, whereas comparatively less attention has been given to the distribution of susceptibility to those inhibitory activities within microbial communities. Here, we examined comparative susceptibility among S. anginosus, S. mitis and S. pyogenes using a defined panel of ten historically characterised bacteriocin-producing streptococci and 46 indicator strains. Deferred-antagonism assays were performed independently on two experimental occasions, with all 460 producer–indicator combinations examined in each run. Susceptibility was scored using an ordinal four-category system based on inhibition-zone characteristics. The resulting susceptibility patterns were highly reproducible, with 93.7% exact categorical agreement between experimental runs and 97.8% agreement within one ordinal category. The isolates examined displayed selective combinations of susceptibility and reduced susceptibility across the producer panel rather than a simple continuum of susceptibility. In particular, the 12 S. anginosus isolates showed no inhibition by either of the two SalA-associated producer activities represented in the panel (0/12 for each in both runs) while remaining susceptible to several alternative producer-associated activities. We use the term Comparative Susceptibility Landscape (CSL) to describe this multidimensional, panel- and assay-dependent susceptibility phenotype. A CSL does not by itself identify a molecular immunity mechanism or demonstrate an ecological interaction. Rather, it provides a structured phenotypic framework from which mechanistic and ecological hypotheses can be developed.
