Flow cytometry and capillary electrophoresis analyses in ethanol-stressedOenococcus oenistrains and changes assessment of membrane fatty acid composition

Recent Advances in Gut Microbiota in Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by joint inflammation and skin lesions. Recent research has underscored the critical role of gut microbiota-comprising bacteria, fungi, viruses, and archaea-in the pathogenesis and progression of PsA. This narrative review synthesizes the latest findings on the influence of gut microbiota on PsA, focusing on mechanisms such as immune modulation, microbial dysbiosis, the gut-joint axis, and its impact on treatment. Advances in high-throughput sequencing and metagenomics have revealed distinct microbial profiles associated with PsA. Studies show that individuals with PsA have a unique gut microbiota composition, differing significantly from healthy controls. Alterations in the abundance of specific bacterial taxa, including a decrease in beneficial bacteria and an increase in potentially pathogenic microbes, contribute to systemic inflammation by affecting the intestinal barrier and promoting immune responses. This review explores the impact of various factors on gut microbiota composition, including age, hygiene, comorbidities, and medication use. Additionally, it highlights the role of diet, probiotics, and fecal microbiota transplantation as promising strategies to modulate gut microbiota and alleviate PsA symptoms. The gut-skin-joint axis concept illustrates how gut microbiota influences not only gastrointestinal health but also skin and joint inflammation. Understanding the complex interplay between gut microbiota and PsA could lead to novel, microbiome-based therapeutic approaches. These insights offer hope for improved patient outcomes through targeted manipulation of the gut microbiota, enhancing both diagnosis and treatment strategies for PsA.

Convergence of flow cytometry and bacteriology. Current and future applications: a focus on food and clinical microbiology

Since its development in the 1960s, flow cytometry (FCM) was quickly revealed a powerful tool to analyse cell populations in medical studies, yet, for many years, was almost exclusively used to analyse eukaryotic cells. Instrument and methodological limitations to distinguish genuine bacterial signals from the background, among other limitations, have hampered FCM applications in bacteriology. In recent years, thanks to the continuous development of FCM instruments and methods with a higher discriminatory capacity to detect low-size particles, FCM has emerged as an appealing technique to advance the study of microbes, with important applications in research, clinical and industrial settings. The capacity to rapidly enumerate and classify individual bacterial cells based on viability facilitates the monitoring of bacterial presence in foodstuffs or clinical samples, reducing the time needed to detect contamination or infectious processes. Besides, FCM has stood out as a valuable tool to advance the study of complex microbial communities, or microbiomes, that are very relevant in the context of human health, as well as to understand the interaction of bacterial and host cells. This review highlights current developments in, and future applications of, FCM in bacteriology, with a focus on those related to food and clinical microbiology.

Antimicrobial and antioxidant properties and quantitative screening of phytochemicals of Fraxinus excelsior L. and Eschscholtzia californica Cham. mother tinctures

The antioxidant and antimicrobial activities of Fraxinus excelsior L. and Eschscholtzia californica Cham. mother tinctures against a range of foodborne bacteria were investigated to determine the major components and to analyse the action spectrum and antimicrobial effectiveness of the extracts. Results demonstrated a significant antioxidant activity of Fraxinus excelsior L. and a lower activity of Eschscholtzia californica Cham. and a good chemical phenolic composition with the highest content of flavonoids. The Fraxinus excelsior L. and Eschscholtzia californica Cham. mother tinctures demonstrated a middle-high antimicrobial activity against, respectively, 66.67% and 43.33% of all tested bacteria. The inhibitory activity showed a moderate effect on the growth of the sensitive strains in presence of extracts minimum inhibitory concentration. The synergistic actions of bioactive compounds detected in the extracts might be on the basis of antioxidant and biological activities observed and should be used in pharmaceutical, food preservation, alternative medicine and natural therapies fields.

Changes in fatty acid composition as a response to glyphosate toxicity in Pseudomonas fluorescens

Excessive use of herbicides decreases soil biodiversity and fertility. The literature on the xenobiotic response by microorganisms is focused on herbicide biodegradation as a selective event. Non-degradation systems independent of selection could allow the survival of tolerant bacteria in contaminated environments, impacting xenobiotic turnover and, consequently, bioremediation strategies. However, it is uncertain whether the response based on these systems requires selective pressure to be effective. The objective here was to analyze non-degradation phenotypes, enzymatic and structural response systems, of Pseudomonas fluorescens CMA-55 strain, already investigated the production pattern of quorum sensing molecules in response to glyphosate, not present at the isolation site. One mode of response was associated with decrease in membrane permeability and effective antioxidative response for 0–2.30 mM glyphosate, at the mid-log growing phase, with higher activities of Mn-SOD, KatA, and KatB, and presence of fatty acids as nonadecylic acid, margaric and lauric acid. The second response system was characterized by lower antioxidative enzymes activity, presence of KatC isoform, and pelargonic, capric, myristic, stearic, palmitoleic and palmitic acid as principal fatty acids, allowing the strain to face stressful conditions in 9.20–11.50 mM glyphosate at the stationary phase. Therefore, the bacterial strain could modify the fatty acid composition and the permeability of membranes in two response modes according to the herbicide concentration, even glyphosate was not previously selective for P. fluorescens, featuring a generalist system based on physiological plasticity.

Metagenomic monitoring of soil bacterial community after the construction of a crude oil flowline

This study aimed to assess the metagenomic changes of soil bacterial community after constructing a crude oil flowline in Basilicata region, Italy. Soils identified a total of 56 taxa at the phylum level and 485 at the family level, with a different taxa distribution, especially in samples collected on 2014. Since microbiological diversity occurred in the soils collected after 2013 (the reference year), we performed a differential abundance analysis using DESeq2 by GAIA pipeline. In the forest area, 14 phyla and 126 families were differentially abundant (- 6.06 < logFC > 7.88) in 2014 compared to 2013. Nine families were differentially abundant in 2015, with logFC between - 3.16 and 4.66, while 20 families were significantly more abundant and 16 less abundant in 2016, with logFC between - 6.48 and 6.45. In the cultivated area, 33 phyla and 260 families showed differential abundance in 2014. In the next year (2015), 14 phyla were significantly more abundant and 19 less abundant, while 29 families were substantially more abundant and 139 less abundant, with fold changes ranging between - 5.67 and 4.01. In 2016, 33 phyla showed a significantly different abundance, as 14 were more abundant and 19 decreased, and 81 families showed a significantly increased amount with logFC between - 5.31 and 5.38. These results hypothesise that the analysed site is an altered soil where the development of particular bacterial groups attends to bioremediation processes, naturally occurring to restore optimal conditions.

A new approach to identifying pathogens, with particular regard to viruses, based on capillary electrophoresis and other analytical techniques

Fast determination, identification and characterization of pathogens is a significant challenge in many fields, from industry to medicine. Standard approaches (e.g., culture media and biochemical tests) are known to be very time-consuming and labor-intensive. Conversely, screening techniques demand a quick and low-cost grouping of microbial isolates, and current analysis call for broad reports of pathogens, involving the application of molecular, microscopy, and electromigration techniques, DNA fingerprinting and also MALDI-TOF methods. The present COVID-19 pandemic is a crisis that affects rich and poor countries alike. Detection of SARS-CoV-2 in patient samples is a critical tool for monitoring disease spread, guiding therapeutic decisions and devising social distancing protocols. The goal of this review is to present an innovative methodology based on preparative separation of pathogens by electromigration techniques in combination with simultaneous analysis of the proteome, lipidome, and genome using laser desorption/ionization analysis.

Evidence of the genetic diversity and clonal population structure of Oenococcus oeni strains isolated from different wine-making regions of China

Studies of the genetic diversity and population structure of Oenococcus oeni (O. oeni) strains from China are lacking compared to other countries and regions. In this study, amplified fragment length polymorphism (AFLP) and multilocus sequence typing (MLST) methods were used to investigate the genetic diversity and regional evolutionary patterns of 38 O. oeni strains isolated from different wine-making regions in China. The results indicated that AFLP was markedly more efficient than MLST for typing O. oeni strains. AFLP distinguished 37 DNA patterns compared to 7 sequence types identified using MLST, corresponding to discriminatory indices of 0.999 and 0.602, respectively. The AFLP results revealed a high level of genetic diversity among the O. oeni strains from different regions of China, since two subpopulations and an intraspecific homology higher than 60% were observed. Phylogenetic analysis of the O. oeni strains using the MLST method also identified two major phylogroups, which were differentiated into two distinct clonal complexes by minimum spanning tree analysis. Neither intragenic nor intergenic recombination verified the existence of the clonal population structure of the O. oeni strains.

Ethanol stress in Oenococcus oeni: transcriptional response and complex physiological mechanisms

Oenococcus oeni is the dominant species able to cope with a hostile environment of wines, comprising cumulative effects of low pH, high ethanol and SO₂ content, nonoptimal growth temperatures and growth inhibitory compounds. Ethanol tolerance is a crucial feature for the activity of O. oeni cells in wine because ethanol acts as a disordering agent of its cell membrane and negatively affects metabolic activity; it damages the membrane integrity, decreases cell viability and, as other stress conditions, delays the start of malolactic fermentation with a consequent alteration of wine quality. The cell wall, cytoplasmic membrane and metabolic pathways are the main sites involved in physiological changes aimed to ensure an adequate adaptive response to ethanol stress and to face the oxidative damage caused by increasing production of reactive oxygen species. Improving our understanding of the cellular impact of ethanol toxicity and how the cell responds to ethanol stress can facilitate the development of strategies to enhance microbial ethanol tolerance; this allows to perform a multidisciplinary endeavour requiring not only an ecological study of the spontaneous process but also the characterization of useful technological and physiological features of the predominant strains in order to select those with the highest potential for industrial applications.