Variation in the microbial community contributes to the improvement of the main active compounds of Magnolia officinalis Rehd. et Wils in the process of sweating

Abstract Background Magnolia officinalis Rehd. et Wils, commonly called Houpo, has been used for thousands of years in China as a traditional herbal medicine. The primary processing of Houpo requires sweating treatment, which is a special drying process and is considered to be an essential embodiment of high quality and genuine medicinal materials. The sweating of Houpo leads to peculiar changes in the microbial community structure and the content of main active substances (magnolol, honokiol, syringin and magnoflorine). Variation in the microbial community was considered the cause of the change in content of active substances of Houpo, although the microbial taxa responsible for the improvement of content remain unidentified. Methods In this study, we used MiSeq high-throughput sequencing methods for partial bacterial 16S rRNA and 18S rRNA gene sequences to compare the bacterial and fungal community structures at different timepoints in the process of sweating. The content of the main active substances (magnolol, honokiol, syringin and magnoflorine) were determined by high-performance liquid chromatography analysis to evaluate the effects of sweating. UPLC-Q-Extractive Orbitrap mass spectrometry (UPLC-QE Orbitrap MS) was used to detection of differential metabolites of unsweated Houpo before and after co-culture with core bacterial solutions. Results In this study, the total contents of magnolol (MG) and honokiol (HK) were significantly increased at 4 dp (dp for day PM sample), up to 3.75%, and the contents of syringin (SG) and magnoflorine (MF) were as high as 0.12% and 0.06%, respectively. Bacterial abundance and diversity were higher in the early stage (0 day–2 da; da for day AM sample) than in the later stage (4–5 dp), while fungal abundance was more obvious in the later stage than in the early stage. Positive correlation coefficients revealed that the relative abundance of Enterobacter (P < 0.05), Klebsiella (P < 0.05), Weissella (P < 0.05), Bacillus (P < 0.05) and Candida (P < 0.05) would be conducive to improving the quality of Houpo. Negative correlation coefficients revealed that the relative abundance of Actinomycetospora, Singulisphaera, Mucilaginibacter, Deinococcus, Gemmatirosa, Methylobacterium, Sphingomonas, Hymenobacter, Halomonas and Capnobotryella could be a potential antagonist for the decrease in the quality of Houpo. After co-culture of single core strain and unsweated Houpo, there was no significant difference in the four main active components, but there were other metabolites with significant difference. Conclusions Our findings reveal that sweating increased the content of the main active compounds, promoted the relative abundance of potentially beneficial microbes, decreased the abundance of potentially harmful microbes, the core functional genera group together, forming a core microbiome, these genera are dominant across the different stages of the sweating process and contribute to the quality development of the characteristics of Houpo. Meanwhile, this study presented a clear scope for potential beneficial microbes that improve the quality of Houpo.

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Current measures of distress may not account for what's most important in existential care interventions: Results of the outlook trial

Palliative & Supportive Care ◽

10.1017/s1478951520001170 ◽

2020 ◽

Vol 18 (6) ◽

pp. 648-657

Author(s):

Karen E. Steinhauser ◽

Karen M. Stechuchak ◽

Katherine Ramos ◽

Joseph Winger ◽

James A. Tulsky ◽

...

Keyword(s):

Quality Of Life ◽

Early Stage ◽

Well Being ◽

Primary Analysis ◽

Significant Difference ◽

Spiritual Well Being ◽

Screening For Distress ◽

Secondary Outcomes ◽

Stage Renal Disease

AbstractObjectiveCompare the efficacy of two interventions addressing emotional and existential well-being in early life-limiting illness.MethodPrimary trial analysis (n = 135) included patients with advanced cancer, congestive heart failure, or end-stage renal disease; Arm 1 received the Outlook intervention, addressing issues of life completion and preparation, and Arm 2 received relaxation meditation (RM). Primary outcomes at five weeks (primary endpoint) and seven weeks (secondary): completion and preparation (QUAL-E); secondary outcomes: anxiety (POMS) quality of life (FACT-G) and spiritual well-being (FACIT-Sp) subscales of faith, meaning, and peace.ResultsAverage age was 62; 56% were post-high school-educated, 54% were married, 52% white, 44% female, and 70% had a cancer diagnosis. At baseline, participants demonstrated low levels of anxiety (<5 on POMS subscale) and depression (<10 on CESD) relative to population norms. Results of the primary analysis revealed no significant differences in mean Preparation by treatment arm at five weeks (14.4 Outlook vs. 14.8 RM; between-group difference −0.4 [95% CI, −1.6, 0.8], p = 0.49) or seven weeks (15.2 vs.15.4; between-group difference −0.2 [95% CI, −1.5, 1.0], p = 0.73). There were also no significant differences in mean Life Completion by treatment arm between five weeks (26.6 Outlook vs. 26.3 RM; between-group difference 0.2 [95% CI, −1.2, 1.7], p = 0.76) or seven weeks (26.5 vs. 27.5; between-group difference −1.0 [95% CI, −2.7, 0.7], p = 0.23). Compared to RM, Outlook participants did not have significant differences over time in the secondary outcomes of overall quality of life, anxiety, depression, FACT-G subscales, and FACIT-Sp subscales.DiscussionIn early-stage life-limiting illness, Outlook did not demonstrate a significant difference in primary or secondary outcomes relative to RM. Results underscore the importance of pre-screening for distress. Qualitatively, Outlook participants were able to express suppressed emotions, place illness context, reflect on adaptations, and strengthen identity. Screening for distress and identifying specified measures of distress, beyond anxiety and depression, is essential in our ability to adequately assess the multi-dimensional mechanisms that decrease existential suffering.

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Profile of microbial community of organic and conventional rice field using metagenomic analysis

Biogenesis Jurnal Ilmiah Biologi ◽

10.24252/bio.v9i1.14228 ◽

2021 ◽

Vol 9 (1) ◽

pp. 1

Author(s):

Arum Asri Trisnastuti ◽

Edi Purwanto ◽

Ari Susilowati

Keyword(s):

Microbial Community ◽

Relative Abundance ◽

Rice Field ◽

Fertilizer Application ◽

Rice Fields ◽

Community Diversity ◽

Total N ◽

Organic C ◽

Organic Rice ◽

Significant Difference

Organic farming can increase the diversity of soil bacterial. This research aimed to compare the profile of microbial community of organic and conventional rice fields in early (0 Day After Planting/DAP), mid (15 DAP), and late (45 DAP) fertilizer application period. The total DNA genome from the soil sample was extracted then analyzed metagenomically using Next Generation Sequencing (NGS). There was nine genus of bacteria found in high relative abundance, 95.28%, while 4.72% included in Domain of Archaea (genus Methanosaeta). Phylum of Firmicutes (genus Clostridium has 24.50% relative abundance, Bacillus 11.90%, Lactobacillus 9.69%); Proteobacteria (genus Defluviicoccus 12.10%, Buchnera 18.46%, Rosenbergiella 2.46%); and Actinobacteria (genus Nocardioides 12.21%, and Streptomyces 3.96%). Meanwhile, the average plant height of organic rice fields was shorter than conventional rice fields got directly measured coincided with soil sampled. Based on alpha and beta diversity analysis, the highest community diversity and abundance were found in organic rice field soil samples taken at 45 DAP, i.e., at the end of the fertilizer application period. However, in both organic and conventional rice field soils, there was almost no significant difference in the bacterial community, so it impacts that organic and conventional systems do not make a real difference in the total N, P available, CEC, and pH values. It makes a significant difference in organic C and organic matters.

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YouTube as a source of information about orthodontic clear aligners

The Angle Orthodontist ◽

10.2319/072419-491.1 ◽

2020 ◽

Vol 90 (3) ◽

pp. 419-424 ◽

Cited By ~ 2

Author(s):

Gokay Ustdal ◽

Ayca Ustdal Guney

Keyword(s):

Pearson Correlation ◽

Correlation Coefficients ◽

Search Term ◽

Sources Of Information ◽

The Poor ◽

Significant Difference ◽

The Rich ◽

Video Group ◽

Rich Content

ABSTRACT Objectives To evaluate the content, reliability, and quality of videos about orthodontic clear aligners on YouTube. Materials and Methods Researchers used the Google Trends website to determine that the most frequently used search term for orthodontic clear aligners on the Internet was: “Invisalign.” A search was then conducted on YouTube using the key word “Invisalign.” From the first 140 results, 100 videos were selected for analysis. A 13-point content score was used to classify poor-content and rich-content videos, and the global quality scale (GQS) was used to examine quality of the videos. To evaluate reliability of the information, a five-question scale was used. The Mann-Whitney U-test, χ2 test, and Pearson correlation coefficients were used for statistical evaluations. Results Of the YouTube videos, 33 were classified as rich content and 67 as poor content. Most videos (73%) were uploaded by laypeople, and most uploaders (71%) were women. The most commonly discussed content was instructions (65%), followed by procedure (57%) and pain (52%). Regarding the GQS, most of the videos were evaluated as moderate quality (51%). Compared with the poor-content video group, the rich-content video group had a significantly higher GQS score (P = .004). There was no significant difference between the poor-content and rich-content groups regarding information reliability (P > .05). Conclusions Video content on YouTube relating to aligner orthodontics was generally insufficient. The quality of videos was moderate, but the reliability of information was generally poor. Specialists should refer patients to reliable sources of information.

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Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Wheat

BioMed Research International ◽

10.1155/2021/8835275 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Xiaohui Wang ◽

Chao Ji ◽

Xin Song ◽

Zhaoyang Liu ◽

Yue Liu ◽

...

Keyword(s):

Microbial Community ◽

Community Composition ◽

Relative Abundance ◽

Phytopathogenic Fungi ◽

Control Group ◽

Composition Analysis ◽

Beneficial Microbes ◽

Treatment Groups ◽

Wheat Rhizosphere ◽

Rhizosphere Microbial Community

Biocontrol by inoculation with beneficial microbes is a proven strategy for reducing the negative effect of soil-borne pathogens. We evaluated the effects of microbial inoculants BIO-1 and BIO-2 in reducing soil-borne wheat diseases and in influencing wheat rhizosphere microbial community composition in a plot test. The experimental design consisted of three treatments: (1) Fusarium graminearum F0609 (CK), (2) F. graminearum + BIO-1 (T1), and (3) F. graminearum F0609 + BIO-2 (T2). The results of the wheat disease investigation showed that the relative efficacies of BIO-1 and BIO-2 were up to 82.5% and 83.9%, respectively. Illumina MiSeq sequencing revealed that bacterial abundance and diversity were significantly higher ( P < 0.05 ) in the treatment groups (T1 and T2) than in the control, with significantly decreased fungal diversity in the T2 group. Principal coordinates and hierarchical clustering analyses revealed that the bacterial and fungal communities were distinctly separated between the treatment and control groups. Bacterial community composition analysis demonstrated that beneficial microbes, such as Sphingomonas, Bacillus, Nocardioides, Rhizobium, Streptomyces, Pseudomonas, and Microbacterium, were more abundant in the treatment groups than in the control group. Fungal community composition analysis revealed that the relative abundance of the phytopathogenic fungi Fusarium and Gibberella decreased and that the well-known beneficial fungi Chaetomium, Penicillium, and Humicola were more abundant in the treatment groups than in the control group. Overall, these results confirm that beneficial microbes accumulate more easily in the wheat rhizosphere following application of BIO-1 and BIO-2 and that the relative abundance of phytopathogenic fungi decreased compared with that in the control group.

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Weaning Age Affects the Development of the Ruminal Bacterial and Archaeal Community in Hu Lambs During Early Life

Frontiers in Microbiology ◽

10.3389/fmicb.2021.636865 ◽

2021 ◽

Vol 12 ◽

Author(s):

Huiling Mao ◽

Yanfang Zhang ◽

Yan Yun ◽

Wenwen Ji ◽

Zhao Jin ◽

...

Keyword(s):

Microbial Community ◽

Relative Abundance ◽

Age Groups ◽

Lactate Concentration ◽

Archaeal Community ◽

Milk Replacer ◽

Significant Difference ◽

Weaning Age ◽

Bacterial And Archaeal Communities ◽

Positive Correlations

Weaning plays an important role in many animal processes, including the development of the rumen microbiota in ruminants. Attaining a better understanding of the development of the rumen microbial community at different weaning stages can aid the identification of the optimal weaning age. We investigated the effects of weaning age on ruminal bacterial and archaeal communities in Hu lambs. Thirty male Hu lambs were randomly assigned to two weaning-age groups: a group weaned at 30 days of age (W30) and a group weaned at 45 days of age (W45), with each group having five replicate pens. On the weaning day (day 30 for W30 and day 45 for W45) and at 5 days postweaning [day 35 for W30 (PW30) and day 50 for W45 (PW45)], one lamb from each replicate was randomly selected and sacrificed. Rumen contents were collected to examine the ruminal microbiota. Compared to W30, PW30 had a decreased relative abundance of Bacteroidetes. At genus level, the extended milk replacer feeding (W45 vs. W30) increased the relative abundance of Ruminococcus while decreased that of Prevotella and Dialister. Compared to W30, PW30 exhibited decreased relative abundances of Prevotella, Dialister and Bacteroides but an increased unclassified Coriobacteriaceae. No significant difference was noted in the detected archaeal taxa among the animals. The function “biosynthesis of secondary metabolites” was less predominant in PW30 than in W30, whereas the opposite held true for “metabolism of cofactors and vitamins.” Some bacterial genera were significantly correlated with rumen volatile fatty acid (VFA) concentration or other animal measures, including negative correlations between ruminal VFA concentration and unclassified Mogibacteriaceae and unclassified Veillonellaceae; positive correlations of ruminal papillae length with Fibrobacter and unclassified Lachnospiraceae, but negative correlations with Mitsuokella and Succiniclasticum; and negative correlations between plasma D-lactate concentration and Prevotella, unclassified Paraprevotellaceae, and Desulfovibrio. Our results revealed that the ruminal bacterial community underwent larger changes over time in lambs weaned at 30 days of age than in lambs weaned half a month later. Thus, extending milk replacer feeding to 45 days weaning was recommended from the perspective of the rumen microbial community in the Hu lamb industry.

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Effects of adding different proportions of soft rock on the dynamic change of the quality of aeolian sandy soil

Bangladesh Journal of Botany ◽

10.3329/bjb.v50i5.56435 ◽

2021 ◽

pp. 837-845

Author(s):

Tingting Cao ◽

Zhen Guo ◽

Juan Li ◽

Haiou Zhang ◽

Hang Zhou ◽

...

Keyword(s):

Microbial Community ◽

Organic Carbon ◽

Carbon Content ◽

Nitrogen Content ◽

Root System ◽

Soft Rock ◽

Ammonium Nitrogen ◽

Organic Carbon Content ◽

Significant Difference

Evolution process of quality of soft rock and sand compound soil and exploration of its stability were studied. In the present study different proportions (1 : 1, 1 : 2, 1 : 5, 0 : 1) of soft rock and sand compound soil as the research object were selected. Tthe particulate organic carbon, microbial organic carbon, effective phosphorus, quick-acting potassium, nitro nitrogen and ammonium nitrogen in the compound soil were analyzed. Results showed that after 9 years of planting, the organic carbon content of particles with 0 : 1 treatment was the lowest, at 1.73 g/kg, and the treatment of 1 : 5 and 1 : 1 increased significantly by 74.74 and 94.90%, respectively. In the 20 - 30 cm soil layer, the lowest organic carbon content of particles with 1 : 2 treatment was 1.92 g/kg, and there was no significant difference between the other three treatments, with 0 : 1, 1 : 5 and 1 : 1 treatment increased by 46.20, 29.27 and 34.07%, respectively compared to 1 : 2 treatment. With developed root system, the biomass of the root system was greater than the biomass left on the ground after harvest, and the average content of organic carbon of the particles increased first and then decreased later. The microbial community in the compound soil was significantly improved, and the carbon content of microorganisms in the treatment of 1 : 1, 1 : 2 and 1 : 5 was significantly higher than that of whole sand by 85, 165 and 143%, respectively, after multi-year of cultivation. The soil root microbial community showed a benign development. With the increase of planting years, the incorporation of soft rock accelerates the process of natural succession of soil quality. Compared with sandy land, compound soil has significantly improved storage of available phosphorus and available potassium nutrients. Compound soil has been cultivated for 9 years compared with 6 years, with the ratio of 1 : 1, 1 : 2, 1 : 5 and 0 : 1, the effective phosphorus content increased significantly by 141, 181, 169 and 63% respectively, the available potassium content increased significantly by 141, 181, 169 and 63% respectively. Compound soil has been cultivated for 9 years compared with 6 years, with the ratio of 1 : 1, 1 : 2, 1 : 5, and 0 : 1, the nitrate nitrogen content increased significantly by 40, 130, 135 and 120%, respectively. Nitro nitrogen is easily soluble in water, and the higher the proportion of sand in the compound soil, the easier the loss of nitrous nitrogen content in the soil. After multiple years of cultivation, the ammonium nitrogen content in the compound soil decreased, with a significant decrease of 35 (p < 0.05), 34 (p < 0.05), 45 (p < 0.05) and 37% (p < 0.05), respectively. Due to the disruption of harvest, the exposure of the surface soil is high, which causes ammonium nitrogen to evaporate. Bangladesh J. Bot. 50(3): 837-845, 2021 (September) Special

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Microbial transformation of traditional fermented fertilizer bokashi alters chemical composition and improves plant growth

10.1101/2021.08.01.454634 ◽

2021 ◽

Author(s):

Nisreen Abo-Sido ◽

John W Goss ◽

Alden Griffith ◽

Vanja Klepac-Ceraj

Keyword(s):

Microbial Community ◽

Plant Growth ◽

Plant Pathogens ◽

Agricultural Waste ◽

Microbial Community Composition ◽

Microbial Transformation ◽

Organic Soil ◽

Microbial Composition ◽

Beneficial Microbes

Bokashi is an organic soil amendment that makes use of microbial processes to break down agricultural waste and create a nutrient-rich fertilizer. The benefits of various types of bokashi on soil fertility and plant growth are well documented, however the changes in microbial community composition and nutrients during bokashi maturation remain poorly characterized. Here, we aimed to identify potential differences in the quality of bokashi made using different ingredients and to investigate the biochemical transformation and microbial community succession of bokashi throughout the maturation process. We compared the effects of these different types of bokashi on the growth of cucumber (Cucumis sativus) and kale (Brassica napus subsp. pabularia) seedlings, measured concentrations of NH4+ and PO43-, and characterized the bokashi bacterial and fungal communities over a 12-day maturation period. We found that cucumber and kale plants growing in all types of bokashi-amended soils exhibited increased chlorophyll levels and dry biomass. During bokashi maturation, we observed a decrease in available PO43-, and an increase in NH4+. There also appeared to be an increase in relative abundances of decomposers and beneficial microbes and a decrease in putative plant pathogens. Regardless of starting bokashi ingredients and differences in microbial composition and nutrient trends, all types of bokashi similarly improve plant growth and contain beneficial microbes.

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Feasibility, Acceptability, and Preliminary Efficacy of Dignity Therapy in Patients With Early Stage Dementia and Their Family. A Pilot Randomized Controlled Trial

Frontiers in Psychiatry ◽

10.3389/fpsyt.2021.795813 ◽

2021 ◽

Vol 12 ◽

Author(s):

Josef Jenewein ◽

Hanspeter Moergeli ◽

Tatjana Meyer-Heim ◽

Peter Muijres ◽

Irene Bopp-Kistler ◽

...

Keyword(s):

Quality Of Life ◽

Interaction Effect ◽

Early Stage ◽

Mean Difference ◽

Psychological Burden ◽

Time Interaction ◽

Dignity Therapy ◽

Significant Difference ◽

Delayed Group

Purpose: Dementia is the major cause for disability and dependence in older people and associated with considerable psychological burden. The aim of this study was to determine the feasibility, acceptability and preliminary efficacy of Dignity Therapy, a brief psychotherapeutic intervention to enhance dignity and reduce psychological burden, in patients with early stage dementia and in their families or close friends.Materials and methods: In this randomized, waitinglist-controlled clinical trial a total of 54 patients with new diagnosis of early stage dementia and 54 study partners (spouses: n = 37; relatives: n = 14; close friends: n = 3) were randomly assigned to immediate treatment (n = 28) or delayed treatment (n = 26) after 3 months waiting. The main outcomes were feasibility: proportion of screened and invited patients who consented participation; Acceptability: number of drop-outs, and satisfaction with treatment; Efficacy: psychological burden (Hospital Anxiety and Depression Scale—HADS), quality of life (WHOQOL-Bref), and sense of dignity (Patient Dignity Inventory—PDI).Results: In total 38.6% of all eligible patients (n = 140) consented and were enrolled. Along the study six participants (11.1%) dropped out. Patients' satisfaction with the treatment was high and with no significant difference between the groups. HADS scores were significantly lower in both groups at the 3-months follow-up (immediate group: mean difference = −2.69, SE = 0.85, P = 0.003; delayed group: mean difference = −1.97, SE = 0.89, P = 0.031). There was no significant group by time interaction effect (F = 0.71; df = 2, 70.3; P = 0.50). PDI scores only decreased significantly (i.e., improvement of dignity) in the immediate group (mean difference = −6.56, SE = 1.63, P < 0.001; delayed group: mean difference = −3.01, SE = 1.69, P = 0.081), but the group by time interaction effect was not statistically significant (F = 2.29; df = 1, 46.8; P = 0.14). Quality of life improved in some respects by the treatment, but the immediate and the delayed group did not differ significantly over time. After pooling patients' data of both groups, Dignity Therapy resulted in significant improvements in almost all outcome measures. Patients' family members/close friends reported high satisfaction with the intervention.Conclusions: Our findings suggest that Dignity Therapy is feasible and highly accepted in patients with early stage dementia. Patients reported significant improvements, however, there was no significant effect of the intervention in the immediate treatment group compared to the delayed group.

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Effects of Giving Asam Gelugur Leaf Meal in Non-Conventional Rations on Carcass Percentage and Carcass Composition of Male and Female Ducks in Grower Phase

Indonesian Journal of Applied Research (IJAR) ◽

10.30997/ijar.v2i1.87 ◽

2021 ◽

Vol 2 (1) ◽

pp. 42-49

Author(s):

Dewi Wahyuni ◽

Burhanudin Malik ◽

Elis Dihansih

Keyword(s):

Carcass Composition ◽

Poultry Farm ◽

Design Factor ◽

Factor B ◽

Male And Female ◽

Leaf Meal ◽

Significant Difference ◽

Males And Females ◽

Active Substances

Ducks are still less liked by consumers because the quality of production is still low compared to broilers. To improve this quality, additional feed can be in the form of herbs which are thought to have content for this. Asam gelugur leaves contain hydroxycitric acid and active substances that act as antioxidants. So that it is expected to improve the quality of the carcass. The purpose of this study was to examine the effect of giving asam gelugur leaf meal on the percentage and composition of male and female ducks in the grower phase. The study was conducted for 2 months in the Poultry Farm of Faculty of Agriculture, Djuanda University. The 40 grower ducks consist of male and female. Fourty male and female grower ducks were allocated into a 2 x 4 completely randomized factorial design. Factor A consisted of sexes (male and female) and factor B consisted of levels of asam gelugur leaf meal inclusion in rations (0, 2, 4, and 6%). five replicates were used for each treatment. The variables observed were slaughter weight, carcass weight, carcass percentage, commercial cut percentage of carcass and duck carcass composition. The results showed that there was no interaction and there was no significant difference (P> 0.05) from giving asam gelugur leaf meal to carcass percentage, carcass commercial cut percentage and duck carcass composition. The conclusion of this study is that giving asam gelugur leaf meal to males and females can maintain the quality of the carcass and the composition of the local duck carcass.

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Profiling of subgingival plaque biofilm microbiota in female adult patients with clear aligners: a three-month prospective study

PeerJ ◽

10.7717/peerj.4207 ◽

2018 ◽

Vol 6 ◽

pp. e4207 ◽

Cited By ~ 4

Author(s):

Runzhi Guo ◽

Yunfei Zheng ◽

Hao Liu ◽

Xiaobei Li ◽

Lingfei Jia ◽

...

Keyword(s):

Microbial Community ◽

Relative Abundance ◽

Orthodontic Treatment ◽

Periodontal Diseases ◽

Subgingival Plaque ◽

Unifrac Distance ◽

Gingival Bleeding ◽

Significant Difference ◽

T1 And T2 ◽

Clear Aligner

Background Clear aligners are well known for facilitating oral hygiene maintenance and decreasing susceptibility to periodontal diseases as compared to conventional fixed appliances. However, few research studies focus on the subgingival microbial community during clear aligner treatment (CAT). Hence, this study investigates changes of the subgingival microbial community and its association with clinical characteristics during the first three months of CAT. Methods Ten female patients with clear aligners were enrolled in this study. Subgingival plaque samples were obtained at three time points: before orthodontic treatment (T0), one month after orthodontic treatment (T1) and three months after orthodontic treatment (T2). DNA was then extracted from plaque samples and analyzed by 16S rRNA gene sequencing. Periodontal examinations, including plaque index (PI) and gingival bleeding index (GBI) measurements were also recorded. Results The plaque indices (PIs) and gingival bleeding indices (GBIs) were slightly increased at T1 and T2, but no statistically significant difference was found. The alpha diversity indices, including the ACE, Chao1, Shannon indices, all showed a declining trend without significance, and a rising trend in the Simpson diversity index was observed. The weighted UniFrac distance was significantly higher at T1 and T2 compared with T0. Principal Coordinates Analysis (PCoA) demonstrated that the communities at T0 tended to cluster apart from the communities at T1 and T2. The relative abundance of the phylum Firmicutes and genus Mycoplasma was significantly increased at T0 compared with T2. There was no significant difference in the relative abundance of periodontal pathogens at the genus and species levels or core microorganisms at the genus level. Conclusion A slightly decreasing microbial diversity with a significant change of microbial structure was found during the first three-month clear aligner treatment (CAT). However, subjects receiving clear aligner treatment were free from periodontal diseases with relatively stable levels of periodontal microorganisms and core microorganisms. Thus, our preliminary findings indicated that clear aligners induced nonpathogenic changes of the subgingival microbiome in the first three-month treatment.

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