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Frontiers in Microbiology 2024Cryoconite is a granular structure present on the glaciers and ice sheets found in polar regions including the Himalayas. It is composed of organic and inorganic matter...
Cryoconite is a granular structure present on the glaciers and ice sheets found in polar regions including the Himalayas. It is composed of organic and inorganic matter which absorb solar radiations and reduce ice surface albedo, therefore impacting the melting and retreat of glaciers. Though climate warming has a serious impact on Himalayan glaciers, the biodiversity of sub-glacier ecosystems is poorly understood. Moreover, cryoconite holes are unique habitats for psychrophile biodiversity hotspots in the NW Himalayas, but unfortunately, studies on the microbial diversity of such habitats remain elusive. Therefore, the current study was designed to explore the bacterial diversity of the Hamtah Glacier Himalaya using both culturable and non-culturable approaches. The culturable bacterial count ranged from 2.0 × 10 to 8.8 × 10 colony-forming units (CFUs)/g at the different locations of the glacier. A total of 88 bacterial isolates were isolated using the culturable approach. Based on the 16S ribosomal RNA gene (16S rRNA), the identified species belong to seven genera, namely, , and . In the non-culturable approach, high-throughput sequencing of 16S rRNA genes (using MiSeq) showed unique bacterial community profiles and represented 440 genera belonging to 20 phyla, namely, Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Acidobacteria, Planctomycetes, Cyanobacteria, Verrucomicrobia, Spirochaetes, Elusimicrobia, Armatimonadetes, Gemmatimonadetes, Deinococcus-Thermus, Nitrospirae, Chlamydiae, Chlorobi, Deferribacteres, Fusobacteria, Lentisphaerae, and others. High relative abundances of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were observed in the samples. Phototrophic (Cyanobacteria and Chloroflexi) and nitrifier (Nitrospirae) in bacterial populations indicated sustenance of the micro-ecosystem in the oligotrophic glacier environment. The isolates varied in their phenotypic characteristics, enzyme activities, and antibiotic sensitivity. Furthermore, the fatty acid profiles of bacterial isolates indicate the predominance of branched fatty acids. Iso-, anteiso-, unsaturated and saturated fatty acids together constituted a major proportion of the total fatty acid composition. High cold-adapted enzyme activities such as lipase and cellulase expressed by (KY783365) and protease and cellulase activities by . strains (KY783373, KY783377-79, KY783382) provide evidence of the possible applications of these organisms. Additionally, antibiotic tests indicated that most isolates were sensitive to antibiotics. In conclusion, the present study contributed for the first time to bacterial diversity and biopotentials of cryoconites of Hamtah Glacier, Himalayas. Furthermore, the cold-adapted enzymes and polyunsaturated fatty acids (PUFAs) may provide an opportunity for biotechnology in the Himalayas. Inductively coupled plasma mass spectrometry (ICPMS) analyses showed the presence of several elements in cryoconites, providing a clue for the accelerating melting and retreating of the Hamtah glacier.
PubMed: 38751720
DOI: 10.3389/fmicb.2024.1362678 -
Frontiers in Oral Health 2024The human oral microbiome may play a role in the development of oral squamous cell carcinoma. The aim of this scoping review was to examine microbial diversity and... (Review)
Review
OBJECTIVES
The human oral microbiome may play a role in the development of oral squamous cell carcinoma. The aim of this scoping review was to examine microbial diversity and differences in the composition of the oral microbiome between OSCC patients and healthy controls.
METHODS
A literature search (in PubMed and Embase.com) was performed on January 9, 2023. The outcome variables used from the included studies of this review were alpha- and beta diversity and oral microbiome composition profiles for each taxonomic level (phylum-, class-, order-, genus- and species level).
RESULTS
Thirteen out of 423 studies were included in this review compromising 1,677 subjects, of which 905 (54.0%) were OSCC patients and 772 (46.0%) were healthy controls. Most studies found a higher alpha diversity in the OSCC patient group and significantly different beta diversities between OSCC patient samples and healthy control samples. Studies reported more abundant (on phylum level), (on genus level), and (on species level) in OSCC patients. The healthy control group had more abundant (on phylum level), and (on genus level) and (on species level) according to most studies.
CONCLUSIONS
Our findings show differences in oral microbiome diversity and composition in OSCC patients. Clinical implications demand continuing study. Development of internationally accepted standard procedures for oral sample collection and oral microbiota analysis is needed for more conclusive and clinically relevant comparisons in future research.
PubMed: 38919733
DOI: 10.3389/froh.2024.1366153 -
Heliyon Sep 2023Variations of cytokines and gut microbiota diversity with improved cognitive function in patients with obesity following bariatric surgery were poorly understood. The...
PURPOSE
Variations of cytokines and gut microbiota diversity with improved cognitive function in patients with obesity following bariatric surgery were poorly understood. The aim of this study was to testify the relationship among gut microbiota, cytokines and cognitive function in patients with obesity before and after laparoscopic sleeve gastrectomy (LSG).
METHODS
Forty patients were enrolled in this study. Demographics, and serum and stool specimens were collected from all patients before and 3 months after LSG. The Montreal Cognitive Assessment (MoCA) scale, as well as assessment of immediate and delayed memory were used to evaluate self-perceived cognitive improvement after LSG.
RESULTS
LSG resulted in significant weight loss and improvement in cognitive functions, as measured by questionnaires. Bariatric surgery tended to increase gut microbiota relative abundance and diversity. The intestinal flora increased in the proportion of and phyla, and decreased in the proportion of , and phyla after LSG. Plasma IL-1β and TNF-α levels were significantly decreased following LSG, while IL-4 was significantly increased. MoCA test scores were significant correlated with IL-4, TNF-α and IL-1β. In addition, had a positive correlation with TNF-α, while had a negative correlation with IL-1β. was negatively correlated with IL-4.
CONCLUSION
Changes in gut microbiota were positive relationship with cognitive function improvement following LSG. Inflammation cytokines maybe played as a mediator between gut microbiota and cognitive function through gut-microbiota-brain axis.
PubMed: 37810155
DOI: 10.1016/j.heliyon.2023.e19245 -
Nutrients Dec 2023A low carbohydrate, high fat (LCHF) diet in athletes increases fat oxidation but impairs sports performance, potentially due to impaired exercise economy. Dietary...
A low carbohydrate, high fat (LCHF) diet in athletes increases fat oxidation but impairs sports performance, potentially due to impaired exercise economy. Dietary nitrate supplementation can improve exercise economy via an increase in nitric oxide production, which is initiated by the reduction of nitrate to nitrite within the oral cavity. This reaction is dependent on the presence of nitrate-reducing oral bacteria, which can potentially be altered by dietary changes, including a LCHF diet. This study explored the effect of a LCHF diet on the oral microbiome and subsequent changes to plasma nitrite concentration following nitrate supplementation. Following five days of LCHF or high carbohydrate (HCHO) control dietary intervention, highly trained male race walkers consumed 140 mL beetroot juice containing 8.4 mmol nitrate; they then provided (a) blood samples for plasma nitrate and nitrite analysis and (b) saliva samples for 16S rRNA sequencing of the oral microbiome. The LCHF diet (n = 13) reduced oral bacterial diversity and changed the relative abundance of the genera (+10%), (+3%), (-9%), and (-4%), with no significant changes observed following the HCHO diet (n = 11). Following beetroot juice ingestion, plasma nitrite concentrations were higher for the LCHF diet compared to the HCHO diet ( = 0.04). However, the absence of an interaction with the trial (pre-post) ( = 0.71) suggests that this difference was not due to the dietary intervention. In summary, we found an increase in plasma nitrate and nitrite concentrations in response to nitrate supplementation independent of diet. This suggests the oral microbiome is adaptive to dietary changes and can maintain a nitrate reduction capacity despite a decrease in bacterial diversity following the LCHF diet.
Topics: Humans; Male; Nitrites; Diet, High-Fat; Nitrates; RNA, Ribosomal, 16S; Microbiota; Bacteria; Carbohydrates; Dietary Supplements; Beta vulgaris
PubMed: 38140382
DOI: 10.3390/nu15245123 -
American Journal of Translational... 2024The prevalence of allergic rhinitis (common allergies) has increased in the last fifty years, from less than one percent to more than twenty-six percent of the...
The prevalence of allergic rhinitis (common allergies) has increased in the last fifty years, from less than one percent to more than twenty-six percent of the population. Today, more than one hundred million people in the US suffer seasonal or yearlong allergies. The hygiene hypothesis was proposed 30 years ago as a potential explanation for this phenomenon, and we built on it with the specific oral hygiene hypothesis. Our longitudinal pilot study suggested that oral probiotic deficiency is the cause of allergic rhinitis. This clinical trial served to verify our theory and evaluate the effectiveness of AllerPops for allergy relief. We carried out a phase II, randomized, double-blind, controlled, single-center 21-day study to investigate the efficacy of AllerPops to reduce nasal symptoms in 72 adult volunteers with seasonal/year-long nasal allergies and its impact on oral microbiome using amplicon sequencing of 16S ribosome RNA genes. The volunteers were randomly separated into two equally sized groups: a control group and an investigational group. Both groups were given at least three doses of AllerPops, taken every other day, and asked to answer questions about observed allergy symptoms. Volunteers in the investigational group cleaned their mouths before taking a dose and slowly dissolve the lozenge, while those in the control did not. Through this trial, we show that AllerPops prebiotic supplements are effective in providing sustained allergy relief (P = 0.002) and can modulate oral beneficial bacteria that produce short-chain fatty acids (SCFA), such as Fusobacteria, Butyrivibrio, and Peptostreptococcus. The clinical improvements correlated with changes in the relative abundance of probiotics significantly: Fusobacteria (R = 0.32, P = 0.009), Butyrivibrio (R = 0.25, P = 0.044), and Peptostreptococcus (R = 0.34, P = 0.005). These results point to the root cause of allergic rhinitis: the lack of oral probiotics that produce SCFA to pacify the immune systems. Future study of AllerPops' theory will help society redefine the best oral hygiene practice to protect oral probiotics so that we may prevent allergic and autoimmune diseases and dental/gum infections. The trial was retrospectively registered at clinicaltrials.com, with registration number NCT05956691, on 21/07/2023.
PubMed: 38322553
DOI: 10.62347/JWOU4205 -
Internal Medicine (Tokyo, Japan) Dec 2023
Topics: Humans; Fusobacterium nucleatum; Lung Abscess; Fusobacterium Infections
PubMed: 37081680
DOI: 10.2169/internalmedicine.1751-23 -
MBio Jan 2024This paper illuminates the significant question of how the oral commensal adapts to the metabolically changing environments of several extra-oral sites such as placenta...
This paper illuminates the significant question of how the oral commensal adapts to the metabolically changing environments of several extra-oral sites such as placenta and colon to promote various diseases as an opportunistic pathogen. We demonstrate here that the highly conserved itrogen-ixation complex, commonly known as Rnf complex, is key to fusobacterial metabolic adaptation and virulence. Genetic disruption of this Rnf complex causes global defects in polymicrobial interaction, biofilm formation, cell growth and morphology, hydrogen sulfide production, and ATP synthesis. Targeted metabolomic profiling demonstrates that the loss of this respiratory enzyme significantly diminishes catabolism of numerous amino acids, which negatively impacts fusobacterial virulence as tested in a preterm birth model in mice.
Topics: Infant, Newborn; Pregnancy; Humans; Female; Animals; Mice; Fusobacterium nucleatum; Virulence; Premature Birth; Placenta; Symbiosis; Multienzyme Complexes
PubMed: 38059640
DOI: 10.1128/mbio.01751-23 -
Frontiers in Cellular and Infection... 2024Trimethylamine-N-oxide (TMAO) is produced by hepatic flavin-containing monooxygenase 3 (FMO3) from trimethylamine (TMA). High TMAO level is a biomarker of cardiovascular...
BACKGROUND
Trimethylamine-N-oxide (TMAO) is produced by hepatic flavin-containing monooxygenase 3 (FMO3) from trimethylamine (TMA). High TMAO level is a biomarker of cardiovascular diseases and metabolic disorders, and it also affects periodontitis through interactions with the gastrointestinal microbiome. While recent findings indicate that periodontitis may alter systemic TMAO levels, the specific mechanisms linking these changes and particular oral pathogens require further clarification.
METHODS
In this study, we established a C57BL/6J male mouse model by orally administering (, ), (, ), (, ) and PBS was used as a control. We conducted LC-MS/MS analysis to quantify the concentrations of TMAO and its precursors in the plasma and cecal contents of mice. The diversity and composition of the gut microbiome were analyzed using 16S rRNA sequencing. TMAO-related lipid metabolism and enzymes in the intestines and liver were assessed by qPCR and ELISA methods. We further explored the effect of on FMO3 expression and lipid molecules in HepG2 cells by stimulating the cells with -LPS .
RESULTS
The three oral pathogenic bacteria were orally administered to the mice for 5 weeks. The group showed a marked increase in plasma TMAO, betaine, and creatinine levels, whereas no significant differences were observed in the gut TMAO level among the four groups. Further analysis showed similar diversity and composition in the gut microbiomes of both the and groups, which were different from the and control groups. The profiles of TMA-TMAO pathway-related genera and gut enzymes were not significantly different among all groups. The group showed significantly higher liver FMO3 levels and elevated lipid factors (IL-6, TG, TC, and NEFA) in contrast to the other groups. experiments confirmed that stimulation of HepG2 cells with -LPS upregulated the expression of FMO3 and increased the lipid factors TC, TG, and IL-6.
CONCLUSION
This study conclusively demonstrates that , compared to and , plays a critical role in elevating plasma TMAO levels and significantly influences the TMA-TMAO pathway, primarily by modulating the expression of hepatic FMO3 and directly impacting hepatic lipid metabolism.
Topics: Animals; Male; Methylamines; Humans; Gastrointestinal Microbiome; Mice; Mice, Inbred C57BL; Oxygenases; Porphyromonas gingivalis; Fusobacterium nucleatum; Metabolic Networks and Pathways; Hep G2 Cells; Lipid Metabolism; Disease Models, Animal; Periodontitis; Liver; RNA, Ribosomal, 16S; Tandem Mass Spectrometry; Mouth
PubMed: 38836053
DOI: 10.3389/fcimb.2024.1413787 -
Annals of Clinical Microbiology and... Nov 2023Peritonsillar abscess (PTA) is a severe deep neck space infection with an insufficiently characterized bacterial etiology. We aimed to reveal the bacteria associated...
BACKGROUND
Peritonsillar abscess (PTA) is a severe deep neck space infection with an insufficiently characterized bacterial etiology. We aimed to reveal the bacteria associated with PTA applying next generation sequencing (NGS). Tonsil biopsies and pus samples of 91 PTA patients were analysed applying NGS method.
RESULTS
Over 400 genera and 800 species belonging to 34 phyla were revealed. The most abundant species in both sample types were Streptococcus pyogenes, Fusobacterium necrophorum and Fusobacterium nucleatum. When present, S. pyogenes was normally a predominant species, although it was recovered as a minor population in some samples dominated by F. nucleatum and occasionally F. necrophorum. S. pyogenes and F. necrophorum were the predominant species (> 10% in a community) in 28 (31%) pus samples, while F. nucleatum in 21 (23%) and S. anginosus in 8 (9%) pus samples. We observed no substantial differences between the microbial findings in pus and tonsil biopsies.
CONCLUSIONS
The most probable causative agents of PTA according to our NGS-study include Streptococcus pyogenes, Fusobacterium necrophorum and Fusobacterium nucleatum. Some other streptococci (S. anginosus) and anaerobes (Prevotella, Porphyromonas) may contribute to the infection as well. Pus of the peritonsillar abscess is more representative specimen for microbiological examination than the tonsillar tissue. Our results are important in the context of optimizing the handling of the PTA patients.
Topics: Humans; Peritonsillar Abscess; High-Throughput Nucleotide Sequencing; Fusobacterium necrophorum; Streptococcus pyogenes
PubMed: 37940951
DOI: 10.1186/s12941-023-00649-0 -
Clinical Oral Investigations Oct 2023The present study aimed to evaluate the potential of the salivary pellicle (SP) formed on titanium (Ti) surfaces to modulate the formation of a biofilm composed of...
OBJECTIVES
The present study aimed to evaluate the potential of the salivary pellicle (SP) formed on titanium (Ti) surfaces to modulate the formation of a biofilm composed of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis.
MATERIALS AND METHODS
Ti substrates were incubated for 2 h with a pool of saliva samples obtained from 10 systemically and periodontally healthy subjects. Enamel substrates were included as a biological reference. Scanning electron microscopy (SEM) and Raman spectroscopy analysis were used to analyze the formation of the salivary pellicle. After the SP formation, the surfaces were incubated for 12 h with a mix of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis. The number of bacterial cells attached to each surface was determined by the XTT assay while bacterial viability was analyzed by fluorescence microscopy using the LIVE/DEAD® BacLight kit.
RESULTS
The SEM and Raman spectroscopy analysis confirmed the presence of a salivary pellicle formed on the tested surfaces. Regarding the biofilm formation, the presence of the SP decreases the number of the bacterial cells detected in the test surfaces, compared with the uncover substrates. Even more, the SP-covered substrates showed similar bacterial counts in both Ti and enamel surfaces, meaning that the physicochemical differences of the substrates were less determinant than the presence of the SP. While on the SP-uncover substrates, differences in the bacterial adhesion patterns were directly related to the physicochemical nature of the substrates.
CONCLUSIONS
The salivary pellicle was the main modulator in the development of the biofilm consisting of representative oral bacteria on the Ti substrates.
CLINICAL RELEVANCE
The results of this study provide valuable information on the modulatory effect of the salivary pellicle on biofilm formation; such information allows us to understand better the events involved in the formation of oral biofilms on Ti dental implants.
Topics: Humans; Dental Pellicle; Titanium; Biofilms; Bacterial Adhesion; Streptococcus gordonii; Fusobacterium nucleatum; Surface Properties
PubMed: 37646908
DOI: 10.1007/s00784-023-05230-9