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Biogeochemical dynamics and microbial community development under sulfate- and iron-reducing conditions based on electron shuttle amendment.
Flynn, TM, Antonopoulos, DA, Skinner, KA, Brulc, JM, Johnston, E, Boyanov, MI, Kwon, MJ, Kemner, KM, O'Loughlin, EJ
PloS one. 2021;(5):e0251883
Abstract
Iron reduction and sulfate reduction are two of the major biogeochemical processes that occur in anoxic sediments. Microbes that catalyze these reactions are therefore some of the most abundant organisms in the subsurface, and some of the most important. Due to the variety of mechanisms that microbes employ to derive energy from these reactions, including the use of soluble electron shuttles, the dynamics between iron- and sulfate-reducing populations under changing biogeochemical conditions still elude complete characterization. Here, we amended experimental bioreactors comprised of freshwater aquifer sediment with ferric iron, sulfate, acetate, and the model electron shuttle AQDS (9,10-anthraquinone-2,6-disulfonate) and monitored both the changing redox conditions as well as changes in the microbial community over time. The addition of the electron shuttle AQDS did increase the initial rate of FeIII reduction; however, it had little effect on the composition of the microbial community. Our results show that in both AQDS- and AQDS+ systems there was an initial dominance of organisms classified as Geobacter (a genus of dissimilatory FeIII-reducing bacteria), after which sequences classified as Desulfosporosinus (a genus of dissimilatory sulfate-reducing bacteria) came to dominate both experimental systems. Furthermore, most of the ferric iron reduction occurred under this later, ostensibly "sulfate-reducing" phase of the experiment. This calls into question the usefulness of classifying subsurface sediments by the dominant microbial process alone because of their interrelated biogeochemical consequences. To better inform models of microbially-catalyzed subsurface processes, such interactions must be more thoroughly understood under a broad range of conditions.
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Probiotic intervention as a potential therapeutic for managing gestational disorders and improving pregnancy outcomes.
Abbasi, A, Aghebati-Maleki, A, Yousefi, M, Aghebati-Maleki, L
Journal of reproductive immunology. 2021;:103244
Abstract
Recent molecular investigations have significantly developed our knowledge of the characteristics of the reproductive microbiome and their associations with host responses to provide an ideal milieu for the development of the embryo during the peri-implantation period and throughout pregnancy as well as to provide a successful in vitro fertilization and appropriate reproductive outcomes. In this context, the establishment of microbial homeostasis in the female reproductive tract, in various physiological periods, is a substantial challenge, which appears the application of probiotics can facilitate the achievement of this goal. So that, currently, probiotics due to its safe and natural features can be considered as a novel biotherapeutic approach. In this review, we comprehensively discuss the bacterial, fungal, and viral diversity detected in the reproductive tract, and their associations with the establishment of dysbiosis/eubiosis conditions as well as we present the significant outcomes on probiotic intervention as an efficient biotherapeutic strategy for management of gestational disorders and improve pregnancy outcomes.
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Novel mechanisms of microbial crosstalk with skin innate immunity.
Chinnappan, M, Harris-Tryon, TA
Experimental dermatology. 2021;(10):1484-1495
Abstract
Skin is an organ with a dynamic ecosystem that harbours pathogenic and commensal microbes, which constantly communicate amongst each other and with the host immune system. Evolutionarily, skin and its microbiota have evolved to remain in homeostasis. However, frequently this homeostatic relationship is disturbed by a variety of factors such as environmental stress, diet, genetic mutations, and the microbiome itself. Commensal microbes also play a major role in the maintenance of microbial homeostasis. In addition to their ability to limit pathogens, many skin commensals such as Staphylococcus epidermidis and Cutibacterium acnes have recently been implicated in disease pathogenesis either by directly modulating the host immune components or by supporting the expansion of other pathogenic microbes. Likewise, opportunistic skin pathogens such as Staphylococcus aureus and Staphylococcus lugdunensis are able to breach the skin and cause disease. Though much has been established about the microbiota's function in skin immunity, we are in a time where newer mechanistic insights rapidly redefine our understanding of the host/microbial interface in the skin. In this review, we provide a concise summary of recent advances in our understanding of the interplay between host defense strategies and the skin microbiota.
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Human Breast Milk Composition and Function in Human Health: From Nutritional Components to Microbiome and MicroRNAs.
Yi, DY, Kim, SY
Nutrients. 2021;(9)
Abstract
Human breast milk (HBM) is not only an indispensable source of nutrients for early human growth and development, supplying components that support infant growth and development, but also contains various essential immunologic components with anti-infectious activities and critical roles in the formation of immunity. It is also known that HBM contains its own unique microbiome, including beneficial, commensal, and potentially probiotic bacteria, that can contribute to infant gut colonization. In addition, HBM-derived extracellular vesicles, exosomes, and microRNA are attracting increasing interest for their potential to transfer to the infant and their role in infant development. In this article, we examine some of the various constituents in HBM and review the evidence supporting their associated health effects and their potential applications in human health.
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A Clinical Trial to Evaluate the Efficacy of α-Viniferin in Staphylococcus aureus - Specific Decolonization without Depleting the Normal Microbiota of Nares.
Rahim, MA, Seo, H, Kim, S, Jeong, YK, Tajdozian, H, Kim, M, Lee, S, Song, HY
Polish journal of microbiology. 2021;(1):117-130
Abstract
Staphylococcus aureus is currently a significant multidrug-resistant bacterium, causing severe healthcare-associated and community-acquired infections worldwide. The current antibiotic regimen against this pathogen is becoming ineffective due to resistance, in addition, they disrupt the normal microbiota. It highlights the urgent need for a pathogen-specific drug with high antibacterial efficacy against S. aureus. α-Viniferin, a bioactive phytochemical compound, has been reported to have excellent anti-Staphylococcus efficacy as a topical agent. However, so far, there were no clinical trials that have been conducted to elucidate its efficacy. The present study aimed to investigate the antibacterial efficacy of α-viniferin against S. aureus in a ten-day clinical trial. Based on the results, α-viniferin showed 50% minimum inhibitory concentrations (MIC50 values) of 7.8 μg/ml in culture broth medium. α-Viniferin was administered in the nares three times a day for ten days using a sterile cotton swab stick. Nasal swab specimens were collected before (0 days) and after finishing the trial (10th day), and then analyzed. In the culture and RT-PCR-based analysis, S. ureus was reduced significantly: 0.01. In addition, 16S ribosomal RNA-based amplicon sequencing analysis showed that S. aureus reduced from 51.03% to 23.99% at the genus level. RNA-seq analysis was also done to gain insights into molecular mechanisms of α-viniferin against S. aureus, which revealed that some gene groups were reduced in 5-fold FC cutoff at two times MIC conditions. The study results demonstrate α-viniferin as a potential S. aureus-specific drug candidate.
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Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals.
Asnicar, F, Berry, SE, Valdes, AM, Nguyen, LH, Piccinno, G, Drew, DA, Leeming, E, Gibson, R, Le Roy, C, Khatib, HA, et al
Nature medicine. 2021;(2):321-332
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Abstract
The gut microbiome is shaped by diet and influences host metabolism; however, these links are complex and can be unique to each individual. We performed deep metagenomic sequencing of 1,203 gut microbiomes from 1,098 individuals enrolled in the Personalised Responses to Dietary Composition Trial (PREDICT 1) study, whose detailed long-term diet information, as well as hundreds of fasting and same-meal postprandial cardiometabolic blood marker measurements were available. We found many significant associations between microbes and specific nutrients, foods, food groups and general dietary indices, which were driven especially by the presence and diversity of healthy and plant-based foods. Microbial biomarkers of obesity were reproducible across external publicly available cohorts and in agreement with circulating blood metabolites that are indicators of cardiovascular disease risk. While some microbes, such as Prevotella copri and Blastocystis spp., were indicators of favorable postprandial glucose metabolism, overall microbiome composition was predictive for a large panel of cardiometabolic blood markers including fasting and postprandial glycemic, lipemic and inflammatory indices. The panel of intestinal species associated with healthy dietary habits overlapped with those associated with favorable cardiometabolic and postprandial markers, indicating that our large-scale resource can potentially stratify the gut microbiome into generalizable health levels in individuals without clinically manifest disease.
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7.
Metabolomics: small molecules that matter more.
Muthubharathi, BC, Gowripriya, T, Balamurugan, K
Molecular omics. 2021;(2):210-229
Abstract
Metabolomics, an analytical study with high-throughput profiling, helps to understand interactions within a biological system. Small molecules, called metabolites or metabolomes with the size of <1500 Da, depict the status of a biological system in a different manner. Currently, we are in need to globally analyze the metabolome and the pathways involved in healthy, as well as diseased conditions, for possible therapeutic applications. Metabolome analysis has revealed high-abundance molecules during different conditions such as diet, environmental stress, microbiota, and disease and treatment states. As a result, it is hard to understand the complete and stable network of metabolites of a biological system. This review helps readers know the available techniques to study metabolomics in addition to other major omics such as genomics, transcriptomics, and proteomics. This review also discusses the metabolomics in various pathological conditions and the importance of metabolomics in therapeutic applications.
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Impact of Streptococcus salivarius K12 on Nasopharyngeal and Saliva Microbiome: A Randomized Controlled Trial.
Sarlin, S, Tejesvi, MV, Turunen, J, Vänni, P, Pokka, T, Renko, M, Tapiainen, T
The Pediatric infectious disease journal. 2021;(5):394-402
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Abstract
BACKGROUND Probiotic lactobacilli have been ineffective in preventing acute otitis media. In contrast to lactobacilli, alpha-hemolytic streptococci belong to the core microbiome of nasopharynx. METHODS We investigated the effects of Streptococcus salivarius K12 probiotic on the saliva and nasopharyngeal microbiome in 121 children attending daycare. Children were randomly allocated to receive oral K12 product for 1 month or no treatment. We obtained saliva and nasopharyngeal samples at study entry, at 1 and 2 months. The next-generation sequencing of the bacterial 16S gene was performed. RESULTS After the intervention, the diversity of saliva or nasopharyngeal microbiome did not differ between groups. The proportion of children with any otopathogen did not differ between the groups. At 1 month, the abundance of otopathogens in nasopharynx was lower in K12 group compared with that in control children (34% vs. 55%, P = 0.037). When we compared each otopathogen separately, Moraxella was the only group lower in the treatment group. We could not verify the reduction of Moraxella when an alternative Human Oral Microbiome Database taxonomy database was used. In children receiving K12 product, the mean abundance of S. salivarius was greater in saliva after the intervention (0.9% vs. 2.0%, P = 0.009). CONCLUSIONS The use of S. salivarius K12 probiotic appeared to be safe because it did not disrupt the normal microbiome in young children. Even though a short-term colonization of S. salivarius was observed in the saliva, the impact of S. salivarius K12 probiotic on the otopathogens in nasopharyngeal microbiome remained uncertain.
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Perspectives on Existing and Novel Alternative Intravaginal Probiotic Delivery Methods in the Context of Bacterial Vaginosis Infection.
Chandrashekhar, P, Minooei, F, Arreguin, W, Masigol, M, Steinbach-Rankins, JM
The AAPS journal. 2021;(3):66
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Abstract
Bacterial vaginosis (BV) is one of the most common vaginal infections that affects hundreds of millions of women of reproductive age, worldwide. Traditional treatment strategies, such as oral and topical antibiotics, have shown efficacy against BV, but frequent recurrence of infection and the development of antibiotic-resistant bacteria remain as significant challenges. Alternatively, recent progress in understanding immune, microbiological, and metabolic interactions in the vaginal microbiota has prompted the consideration of administering probiotic organisms to restore and maintain vaginal health within the context of BV prevention and treatment. Given this, the objective of this review is to discuss existing and potential alternative approaches to deliver, and to potentially sustain the delivery of probiotics, to prevent and/or treat BV infections. First, a brief overview is provided regarding the probiotic species and combinatorial probiotic strategies that have shown promise in the treatment of BV and in restoring female reproductive health. Additionally, the advantages and challenges associated with current oral and intravaginal probiotic delivery platforms are discussed. Lastly, we present emerging and promising alternative dosage forms, such as electrospun fibers and 3D bioprinted scaffolds, that may be adapted as new strategies to intravaginally deliver probiotic organisms. Graphical abstract.
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Early life microbial exposures and allergy risks: opportunities for prevention.
Renz, H, Skevaki, C
Nature reviews. Immunology. 2021;(3):177-191
Abstract
Allergies, including asthma, food allergy and atopic dermatitis, are increasing in prevalence, particularly in westernized countries. Although a detailed mechanistic explanation for this increase is lacking, recent evidence indicates that, in addition to genetic predisposition, lifestyle changes owing to modernization have an important role. Such changes include increased rates of birth by caesarean delivery, increased early use of antibiotics, a westernized diet and the associated development of obesity, and changes in indoor and outdoor lifestyle and activity patterns. Most of these factors directly and indirectly impact the formation of a diverse microbiota, which includes bacterial, viral and fungal components; the microbiota has a leading role in shaping (early) immune responses. This default programme is markedly disturbed under the influence of environmental and lifestyle risk factors. Here, we review the most important allergy risk factors associated with changes in our exposure to the microbial world and the application of this knowledge to allergy prevention strategies.