Nano-plastics (NPs) have emerged as prevalent contaminants in aquatic ecosystems, gaining significant research interest. Nonetheless, limited research has addressed the toxicity mechanisms associated ...with PS-NPs (polystyrene nanoplastics) of varying particle sizes. In this investigation, genotoxicity, growth patterns, hepatopancreatic damage, and intestinal flora alterations in freshwater shrimp Neocaridina palmata (Shen 1948), subjected to 35 days PS-NPs exposure (two size PS-NPs: 75 nm and 200 nm were used for this experiment, and five concentrations were set: 0 mg/L, 0.5 mg/L, 2.5 mg/L, 5 mg/L, and 10 mg/L concentrations PS-NP concentrations were examined using RNA sequencing, histopathological analyses, enzyme activity assessments, and 16S rRNA sequencing. Noteworthy variations in differentially expressed genes (DEGs) were identified across groups exposed to different PS-NPs sizes. We observed that PS-NPs predominantly instigated cellular component-related processes and induced apoptosis and oxidative stress across tissues via the mitochondrial pathway. Although the 200 nm-PS-NPs are stronger than the 75 nm-PS-NPs in terms of fluorescence intensity, 75 nm-PS-NPs are more likely to promote apoptosis than 200 nm-PS-NPs. PS-NPs impeded standard energy provision in N. palmata, potentially contributing to decreased body length and weight. Moreover, PS-NPs inflicted damage on intestinal epithelial and hepatopancreatic tissues and significantly modified intestinal microbial community structures. Specifically, PS-NPs-induced intestinal damage was marked by a decline in some probiotics (notably Lactobacilli) and a surge in pathogenic bacteria. Moreover, supplementing N. palmata with Lactobacilli appeared ameliorate oxidative stress and strengthen energy metabolism. Our findings provided valuable insights into crustacean toxicity mechanisms when subjected to PS-NPs and the potential risks that different PS-NPs sizes posed to terrestrial ecosystems.
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•NPs induced apoptosis and oxidative stress.•NPs reduced standard energy provision, thereby inhibiting growth.•NPs caused intestinal and hepatopancreas damage, and altered the microbiota.•Lactobacilli supplementation may improve the adverse effects of NPs.
Mechanisms of Action of Probiotics Plaza-Diaz, Julio; Ruiz-Ojeda, Francisco Javier; Gil-Campos, Mercedes ...
Advances in nutrition (Bethesda, Md.),
01/2019, Volume:
10, Issue:
suppl_1
Journal Article
Peer reviewed
Open access
ABSTRACT
Probiotics are living microorganisms that confer health benefits to the host when administered in adequate amounts; however, dead bacteria and their components can also exhibit probiotic ...properties. Bifidobacterium and strains of lactic acid bacteria are the most widely used bacteria that exhibit probiotic properties and are included in many functional foods and dietary supplements. Probiotics have been shown to prevent and ameliorate the course of digestive disorders such as acute, nosocomial, and antibiotic-associated diarrhea; allergic disorders such as atopic dermatitis (eczema) and allergic rhinitis in infants; and Clostridium difficile–associated diarrhea and some inflammatory bowel disorders in adults. In addition, probiotics may be of interest as coadjuvants in the treatment of metabolic disorders, including obesity, metabolic syndrome, nonalcoholic fatty liver disease, and type 2 diabetes. However, the mechanisms of action of probiotics, which are diverse, heterogeneous, and strain specific, have received little attention. Thus, the aim of the present work was to review the main mechanisms of action of probiotics, including colonization and normalization of perturbed intestinal microbial communities in children and adults; competitive exclusion of pathogens and bacteriocin production; modulation of fecal enzymatic activities associated with the metabolization of biliary salts and inactivation of carcinogens and other xenobiotics; production of short-chain and branched-chain fatty acids, which, in turn, have wide effects not only in the intestine but also in peripheral tissues via interactions with short-chain fatty acid receptors, modulating mainly tissue insulin sensitivity; cell adhesion and mucin production; modulation of the immune system, which results mainly in the differentiation of T-regulatory cells and upregulation of anti-inflammatory cytokines and growth factors, i.e., interleukin-10 and transforming growth factor; and interaction with the brain-gut axis by regulation of endocrine and neurologic functions. Further research to elucidate the precise molecular mechanisms of action of probiotics is warranted.
The human vaginal microbiome is dominated by bacteria from the genus
, which create an acidic environment thought to protect women against sexually transmitted pathogens and opportunistic infections. ...Strikingly, lactobacilli dominance appears to be unique to humans; while the relative abundance of lactobacilli in the human vagina is typically >70%, in other mammals lactobacilli rarely comprise more than 1% of vaginal microbiota. Several hypotheses have been proposed to explain humans' unique vaginal microbiota, including humans' distinct reproductive physiology, high risk of STDs, and high risk of microbial complications linked to pregnancy and birth. Here, we test these hypotheses using comparative data on vaginal pH and the relative abundance of lactobacilli in 26 mammalian species and 50 studies (
= 21 mammals for pH and 14 mammals for lactobacilli relative abundance). We found that non-human mammals, like humans, exhibit the lowest vaginal pH during the period of highest estrogen. However, the vaginal pH of non-human mammals is never as low as is typical for humans (median vaginal pH in humans = 4.5; range of pH across all 21 non-human mammals = 5.4-7.8). Contrary to disease and obstetric risk hypotheses, we found no significant relationship between vaginal pH or lactobacilli relative abundance and multiple metrics of STD or birth injury risk (
-values ranged from 0.13 to 0.99). Given the lack of evidence for these hypotheses, we discuss two alternative explanations: the common function hypothesis and a novel hypothesis related to the diet of agricultural humans. Specifically, with regard to diet we propose that high levels of starch in human diets have led to increased levels of glycogen in the vaginal tract, which, in turn, promotes the proliferation of lactobacilli. If true, human diet may have paved the way for a novel, protective microbiome in human vaginal tracts. Overall, our results highlight the need for continuing research on non-human vaginal microbial communities and the importance of investigating both the physiological mechanisms and the broad evolutionary processes underlying human lactobacilli dominance.
The human body is colonized by a vast number of microorganisms collectively referred to as the human microbiota. One of the main microbiota body sites is the female genital tract, commonly dominated ...by Lactobacillus spp., in approximately 70% of women. Each individual species can constitute approximately 99% of the ribotypes observed in any individual woman. The most frequently isolated species are Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii and Lactobacillus iners. Residing at the port of entry of bacterial and viral pathogens, the vaginal Lactobacillus species can create a barrier against pathogen invasion since mainly products of their metabolism secreted in the cervicovaginal fluid can play an important role in the inhibition of bacterial and viral infections. Therefore, a Lactobacillus-dominated microbiota appears to be a good biomarker for a healthy vaginal ecosystem. This balance can be rapidly altered during processes such as menstruation, sexual activity, pregnancy and various infections. An abnormal vaginal microbiota is characterized by an increased diversity of microbial species, leading to a condition known as bacterial vaginosis. Information on the vaginal microbiota can be gathered from the analysis of cervicovaginal fluid, by using the Nugent scoring or the Amsel's criteria, or at the molecular level by investigating the number and type of Lactobacillus species. However, when translating this to the clinical setting, it should be noted that the absence of a Lactobacillus-dominated microbiota does not appear to directly imply a diseased condition or dysbiosis. Nevertheless, the widely documented beneficial role of vaginal Lactobacillus species demonstrates the potential of data on the composition and activity of lactobacilli as biomarkers for vaginal health. The substantiation and further validation of such biomarkers will allow the design of better targeted probiotic strategies.
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•Strains grown with 5 % mangosteen extract showed increased antioxidant capacity.•Growth with 5 % mangosteen extract reduced strain biofilm formation.•Most strains were suitable for ...production of functional fermented milk products.•Mangosteen fermented milk products had increased polyphenol and antioxidant levels.
Mangosteen (Garcinia mangostana L.) is a tasty, polyphenol-rich tropical fruit. The edible part is highly appreciated by its aroma, taste and texture. The non-edible part, rich in polyphenols, has been traditionally used in Thai medicine. In this work, flavonoids and phenolic acid/derivatives were identified in mangosteen extracts (ME) from edible and non-edible portions. We first studied the effects of MEs on the growth, metabolism, antioxidant capacity, biofilm formation and antimicrobial capacity of eight bifidobacteria and lactobacilli strains from intestinal origin and two commercial probiotic strains (BB536 and GG). ME concentrations higher than 10–20 % were inhibitory for all strains. However, ME concentrations of 5 % significantly (P < 0.01) increased all strains antioxidant capacity, reduced biofilm-formation, and enhanced inhibition against Gram-positive pathogens. To apply these knowledge, bifunctional fermented milk products were elaborated with 5 % ME and individual strains, which were selected taking into account their growth with ME, and the widest range of values on antioxidant capacity, biofilm formation and antimicrobial activity (bifidobacteria INIA P2 and INIA P467, lactobacilli INIA P459 and INIA P708, and reference strain GG). Most strains survived well manufacture, refrigerated storage and an in vitro simulation of major conditions encountered in the gastrointestinal tract. As expected, products supplemented with ME showed higher polyphenol content and antioxidant capacity levels than control. After sensory evaluation, products containing strains INIA P2, INIA P708 and GG outstood as best.
The microbial communities, their predicted functional roles and associated flavour compounds in three typical traditional Chinese fermented vegetable (TCFV) foods, viz. Jiangxi yancai (JX), Sichuan ...paocai (SC) and Dongbei suancai (DB) were revealed by gene sequencing, predictive functionality and correlation analysis. Bacterial community analysis showed that Lactobacilli made up a large proportion (up to 77.6%) of the species in each food type and revealed clear differences in bacterial community structure among the three types. Lactobacillus sakei, Lactobacillus acetotolerans, and Pediococcus pentosaceus were found to be markers of the DB, SC, JX types, respectively. Overall, 8 organic acids (OAs), 17 amino acids (AAs) and 97 volatile flavour compounds (VFCs) were detected. Several Lactobacilli were closely correlated with more than 20 flavour compounds. Based on their abundance and putative contributions to flavour, Lactobacillus acetotolerans and Lactobacillus sakei may be considered core functional microbiota of each of the three TCFV foods. Functional analysis showed that microbial metabolism of carbohydrates, amino acids and nucleotides is a major determinant of the characteristics of all three TCFV product types. The systematic method used in this study allows identification of the key microorganisms involved in vegetable fermentation and provides a deeper understanding of their contribution to TCFV products.
•Bacterial profiles in three kinds of Chinese fermented vegetables were revealed.•8 organic acids, 17 amino acids and 97 volatile flavours were detected in TCFV.•Correlation between microbial diversity and corresponding flavour was revealed.•Lactobacillus acetotolerans and Lactobacillus sakei were selected as core microbiota.•Metabolism was the primary impetus of the microbial community in samples.
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