Relationship between hyperlipidemia and the gut microbiome of rats, characterized using high-throughput sequencing

Objective:To determine the effects of a high-fat diet(HFD)on the gut microbiome in rats,to explore the relationship between the intestinal flora and blood lipid profile.Methods:SpragueeDawley rats were fed an HFD for four weeks to induce hyperlipidemia,then 16S rRNA sequencing was used to compare the intestinal flora between hyperlipidemic and control diet-fed rats.Results:The microbiome of rats fed an HFD for four weeks differed from that of control diet-fed rats.Bacterial species that were less abundant were most affected by HFD feeding,among which were many pathogenic species,which became significantly more abundant.Eighteen genera were present in significantly different numbers in hyperlipidemic and control rats,more than half of which have been linked to infection and inflammation,or energy intake and obesity.The results indicated a type of stress response of the flora to a high-fat environment.In addition,the age of the rats tended to influence the gut microbial composition.Conclusion:These findings suggest that HFD may induce hyperlipidemia by affecting the gut microbial composition.Changes in the abundance of pro-inflammatory and pathogenic bacteria,and those that influence energy intake and obesity,may be important mediators of this.

Identification of Bacterial Fish Pathogens in Brazil by Direct Colony PCR and 16S rRNA Gene Sequencing

Intensive fish farming systems in Brazil have increased the disease incidence, mainly of bacterial origin, due to higher stocking density, high organic matter levels and poor quality of the aquatic environment that causes high mortality rates during outbreaks. The identification of pathogenic species using a fast and reliable method of diagnosis is essential for successful epidemiological studies and disease control. The present study evaluated the use of direct colony PCR in combination with 16S rRNA gene sequencing to diagnose fish bacterial diseases, with the goal of reducing the costs and time necessary for bacterial identification. The method was successful for all 178 isolates tested and produced bands with the same intensity as the standard PCR performed using pure DNA. In conclusion, the genetics methods allowed detecting the most common and important pathogens in Aquaculture, including 12 species of occurrence in Brazilian fish farms. The results of the present study constitute an advance in the available diagnostic methods for bacterial pathogens in fish farms.

Enterococcus faecalis provides protection during scavenging in carrion crow (Corvus corone)

The gut microbiota significantly influences host physiology and provides essential ecosystem services.While diet can affect the composition of the gut microbiota,the gut microbiota can also help the host adapt to specific dietary habits.The carrion crow(Corvus corone),an urban facultative scavenger bird,hosts an abundance of pathogens due to its scavenging behavior.Despite this,carrion crows infrequently exhibit illness,a phenomenon related to their unique physiological adaptability.At present,however,the role of the gut microbiota remains incompletely understood.In this study,we performed a comparative analysis using 16S rRNA amplicon sequencing technology to assess colonic content in carrion crows and 16 other bird species with different diets in Beijing,China.Our findings revealed that the dominant gut microbiota in carrion crows was primarily composed of Proteobacteria(75.51%)and Firmicutes(22.37%).Significant differences were observed in the relative abundance of Enterococcus faecalis among groups,highlighting its potential as a biomarker of facultative scavenging behavior in carrion crows.Subsequently,E.faecalis isolated from carrion crows was transplanted into model mice to explore the protective effects of this bacterial community against Salmonella enterica infection.Results showed that E.faecalis down-regulated the expression of pro-inflammatory cytokines tumor necrosis factor alpha(TNF-α),interferon gamma(IFN-γ),and interleukin 6(IL-6),prevented S.enterica colonization,and regulated the composition of gut microbiota in mice,thereby modulating the host’s immune regulatory capacity.Therefore,E.faecalis exerts immunoregulatory and anti-pathogenic functions in carrion crows engaged in scavenging behavior,offering a representative case of how the gut microbiota contributes to the protection of hosts with specialized diets.

Intratumoural microorganism can affect the progression of hepatocellular carcinoma

BACKGROUND Several recent studies have confirmed that intratumoural microorganisms can affect the occurrence and development of hepatocellular carcinoma(HCC);however,their role in tumor progression remains unclear.Hence,there is a need for further research on the role of intratumoural microorganisms in HCC.AIM To investigate the changes in intratumoural microorganisms in HCC and the effect of Propionibacterium on HCC progression.METHODS HCC and normal liver tissue specimens were subjected to fluorescence in situ hybridization(FISH).After performing 16S rRNA sequencing on HCC and peritumoral tissues to analyze the differences between the two groups.Propionibacterium was cocultured with HCC cells in vitro.Changes in cell proliferation and migration capacity were evaluated.The expression of NF-κB pathway related proteins in tumor cells was compared.The orthotopic liver implantation model and the subcutaneous xenograft model were constructed.liver tissues and subcutaneous tumors were collected 2 weeks later.RESULTS FISH demonstrated the presence of microorganisms in HCC and normal liver tissues.16S rRNA sequencing revealed an abundance of Lysobacter,Lachnospiraceae,Pseudomonas,and Lactobacillus in HCC tissues.The distribution and abundance of Propionibacterium showed differences between HCC and peritumoral tissues(P<0.05).In vitro studies demonstrated that Propionibacterium and its metabolite propionic acid(PA)inhibited the proliferation and migration of HCC cells(P<0.05).The expression of the proteins in NF-κB signaling pathway also decreased in HCC cells(P<0.05).CONCLUSION Microorganisms in HCC and normal liver tissues displayed significant disparities.The PA-producing bacterium Propionibacterium in HCC exerts an effect on the NF-κB pathway,thereby affecting the biological behavior of HCC.

Effects of reclaimed water irrigation and nitrogen fertilization on the chemical properties and microbial community of soil

The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen（N）levels are important indicators of the effect of reclaimed water irrigation on environment.This study evaluated soil physicochemical properties and microbial community structure in soils irrigated with reclaimed water and receiving varied amounts of N fertilizer.The results indicated that the reclaimed water irrigation increased soil electrical conductivity（EC）and soil water content（SWC）.The N treatment has highly significant effect on the ACE,Chao,Shannon（H）and Coverage indices.Based on a 16S ribosomal RNA（16S rRNA）sequence analysis,the Proteobacteria,Gemmatimonadetes and Bacteroidetes were more abundant in soil irrigated with reclaimed water than in soil irrigated with clean water.Stronger clustering of microbial communities using either clean or reclaimed water for irrigation indicated that the type of irrigation water may have a greater influence on the structure of soil microbial community than N fertilizer treatment.Based on a canonical correspondence analysis（CCA）between the species of soil microbes and the chemical properties of the soil,which indicated that nitrate N（NO3-–-N）and total phosphorus（TP）had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes,meanwhile the p H and organic matter（OM）had impact on abundance of Firmicutes and Actinobacteria significantly.It was beneficial to the improvement of soil bacterial activity and fertility under 120 mg kg^-1 N with reclaimed water irrigation.

Effects of sepsis and its treatment measures on intestinal flora structure in critical care patients

BACKGROUND Sepsis is a common disease in intensive care units,with high morbidity and mortality.Intestinal microecology plays a vital part in the development and progression of this disease,possibly because sepsis and its treatment cause specific changes in the composition of the intestinal flora.AIM To investigate the characteristics of intestinal flora disturbance in sepsis patients treated with antibiotics.METHODS In this prospective comparative study,we enrolled ten patients with sepsis(sepsis group),hospitalized in the Department of Critical Care Medicine of the General Hospital,Ningxia Medical University,China(a class IIIa general hospital)from February 2017 to June 2017;ten patients without sepsis hospitalized in the same period(non-sepsis group)and ten healthy individuals(control group)were also enrolled.Fecal samples collected from the three groups were subjected to 16S rRNA gene sequencing and the intestinal flora diversity,structure,and composition were determined.Additionally,the dynamics of the intestinal flora diversity,structure,and composition in sepsis patients were investigated via 16S rRNA gene sequencing of samples collected 0 d,3 d,and 7 d after admittance to the intensive care unit.Correlations between the serum levels of procalcitonin,endotoxin,diamine oxidase,and D-lactic acid and the intestinal flora composition of sepsis patients were also investigated.RESULTS Compared with the healthy control group,sepsis and non-sepsis patients showed reduced intestinal floraα-diversity and a distinct flora structure,with Firmicutes as the dominant phylum,and significantly decreased proportions of Bacteroidetes,as well as Prevotella and Lachnospira,among other genera.Of note,the proportion of Enterococcus was significantly increased in the intestinal tract of sepsis patients.Interestingly,theα-diversity in the sepsis group decreased gradually,from days 1 to 7 of treatment.However,pairwise comparisons showed that both the diversity and structure of the intestinal flora were not significantly different considering the three different time points studied.Curiously,the serum levels of procalcitonin,endotoxin,diamine oxidase,and D-lactic acid in sepsis patients correlated with the prevalence of various bacterial genera.For example,the prevalence of Ruminococcus was positively correlated with serum procalcitonin,endotoxins,and diamine oxidase;similarly,the prevalence of Roseburia was positively correlated with serum procalcitonin,endotoxins,and D-lactic acid.CONCLUSION Sepsis patients in intensive care units show dysbiosis,lasting for at least 1 wk.

Preliminary study on mitochondrial 16S rRNA gene sequences and phylogeny of flatfishes (Pleuronectiformes)

A 605 bp section of mitochondrial 16S rRNA gene from Paralichthys olivaceus, Pseudorhombus cinnamomeus, Psetta maxima and Kareius bicoloratus, which represent 3 families of Order Pleuronectiformes was amplified by PCR and sequenced to show the molecular systematics of Pleuronectiformes for comparison with related gene sequences of other 6 flatfish downloaded from GenBank. Phylogenetic analysis based on ge- netic distance from related gene sequences of 10 flatfish showed that this method was ideal to explore the rela- tionship between species, genera and families. Phylogenetic trees set-up is based on neighbor-joining, maximum parsimony and maximum likelihood methods that accords to the general rule of Pleuronectiformes evolution. But they also resulted in some confusion. Unlike data from morphological characters, P. olivaceus clustered with K. bicoloratus, but P. cinnamomeus did not cluster with P. olivaceus, which is worth further studying.

Gut mucosal microbiota profiles linked to colorectal cancer recurrence

BACKGROUND Emerging evidence links gut microbiota to various human diseases including colorectal cancer(CRC)initiation and development.However,gut microbiota profiles associated with CRC recurrence and patient prognosis are not completely understood yet,especially in a Chinese cohort.AIM To investigate the relationship between gut mucosal microbiota profiles and CRC recurrence and patient prognosis.METHODS We obtained the composition and structure of gut microbiota collected from 75 patients diagnosed with CRC and 26 healthy controls.The patients were followed up by regular examination to determine whether tumors recurred.Triplet-paired samples from on-tumor,adjacent-tumor and off-tumor sites of patients diagnosed with/without CRC recurrence were analyzed to assess spatial-specific patterns of gut mucosal microbiota by 16S ribosomal RNA sequencing.Next,we carried out bioinformatic analyses,Kaplan-Meier survival analyses and Cox regression analyses to determine the relationship between gut mucosal microbiota profiles and CRC recurrence and patient prognosis.RESULTS We observed spatial-specific patterns of gut mucosal microbiota profiles linked to CRC recurrence and patient prognosis.A total of 17 bacterial genera/families were identified as potential biomarkers for CRC recurrence and patient prognosis,including Anaerotruncus,Bacteroidales,Coriobacteriaceae,Dialister,Eubacterium,Fusobacterium,Filifactor,Gemella,Haemophilus,Mogibacteriazeae,Pyramidobacter,Parvimonas,Porphyromonadaceae,Slackia,Schwartzia,TG5 and Treponema.CONCLUSION Our work suggests that intestinal microbiota can serve as biomarkers to predict the risk of CRC recurrence and patient death.

Salmonella Typhimurium infection disrupts but continuous feeding of Bacillus based probiotic restores gut microbiota in infected hens

Background:The gut microbiota plays an important role in the colonisation resistance and invasion of pathogens.Salmonella Typhimurium has the potential to establish a niche by displacing the microbiota in the chicken gut causing continuous faecal shedding that can result in contaminated eggs or egg products.In the current study,we investigated the dynamics of gut microbiota in laying chickens during Salmonella Typhimurium infection.The optimisation of the use of an infeed probiotic supplement for restoration of gut microbial balance and reduction of Salmonella Typhimurium load was also investigated.Results:Salmonella infection caused dysbiosis by decreasing(FDR<0.05)the abundance of microbial genera,such as Blautia,Enorma,Faecalibacterium,Shuttleworthia,Sellimonas,Intestinimonas and Subdoligranulum and increasing the abundance of genera such as Butyricicoccus,Erysipelatoclostridium,Oscillibacter and Flavonifractor.The higher Salmonella Typhimurium load resulted in lower(P<0.05)abundance of genera such as Lactobacillus,Alistipes,Bifidobacterium,Butyricimonas,Faecalibacterium and Romboutsia suggesting Salmonella driven gut microbiota dysbiosis.Higher Salmonella load led to increased abundance of genera such as Caproiciproducens,Acetanaerobacterium,Akkermansia,Erysipelatoclostridium,Eisenbergiella,EscherichiaShigella and Flavonifractor suggesting a positive interaction of these genera with Salmonella in the displaced gut microbiota.Probiotic supplementation improved the gut microbiota by balancing the abundance of most of the genera displaced by the Salmonella challenge with clearer effects observed with continuous supplementation of the probiotic.The levels of acetate and butyrate in the faeces were not affected(P>0.05)by Salmonella challenge and the butyrate level was increased by the continuous feeding of the probiotic.Probiotic supplementation in Salmonella challenged chickens resulted in higher level of propionate.Continuous probiotic supplementation decreased(P<0.05)the overall mean load of Salmonella in faeces and had a significant effect on Salmonella load reduction in internal organs.Conclusions:Salmonella challenge negatively impacts the diversity and abundance of many gut microbial genera involved in important functions such as organic acid and vitamin production.Strategic feeding of a Bacillus based probiotic helps in restoring many of the microbial genera displaced by Salmonella Typhimurium challenge.

A novel apidaecin Api-PR19 synergizes with the gut microbial community to maintain intestinal health and promote growth performance of broilers

Background: Antibiotic growth promoters(AGPs) have been used as growth promoters to maintain animal intestinal health and improve feed efficiency in broilers by inhibiting pathogen proliferation. In view of the growing emergence of antibiotic-resistant pathogen strains and drug residue issues, novel treatments are increasingly required. This study aimed to compare two antimicrobial approaches for managing pathogen infection and maintaining animal intestinal health in broilers by supplying Apidaecin Api-PR19 and AGPs over 42 d of a feeding trial.Results: Compared with the broilers that were only fed a corn-soybean basal diet(CON group), supplementation with Api-PR19 and AGP(respectively named the ABP and AGP groups) both increased the feed conversion efficiency. When compared with the AGP group, Api-PR19 supplementation could significantly increase the organ index of the bursa of fabricius and subtype H9 antibody level in broiler chickens. Moreover, when compared with the CON group, the intestinal villus height, intestinal nutrient transport, and intestinal s Ig A content were all increased in the Api-PR19 group, while AGP supplementation was harmful to the intestinal villus height and intestinal nutrient transport. By assessing the antibacterial effect of Api-PR19 and antibiotics in vitro and in vivo, we found that Api-PR19 and antibiotics both inhibited the growth of pathogens, including Escherichia coli and Campylobacter jejuni. Furthermore, by using 16 S r RNA gene sequencing, the beneficial bacteria and microbiota in broilers were not disturbed but improved by apidaecin Api-PR19, including the genera of Eubacterium and Christensenella and the species of uncultured_Eubacterium_sp, Clostridium_asparagiforme, and uncultured_Christensenella_sp, which were positively related to improved intestinal development, absorption, and immune function.Conclusion: Apidaecin Api-PR19 treatment could combat pathogen infection and had little negative impact on beneficial bacteria in the gut compared to antibiotic treatment, subsequently improving intestinal development,absorption, and immune function.

Disruption of bacterial balance in the gut of Portunus trituberculatus induced by Vibrio alginolyticus infection

A bstract Gut microbiota impacts the health of crustaceans. V ibrio alginolyticus is a main causative pathogen that induces the vibriosis in farmed swimming crabs, Portunus trituberculatus. However, it remains unknown whether gut bacteria perform functions during the progression of vibriosis. In this study, 16 SrRNA gene amplicon sequencing was used to investigate temporal alteration of gut bacterial community in swimming crabs in response to 72-h V. alginolyticus challenge. Our results show that V. alginolyticus infection resulted in dynamic changes of bacterial community composition in swimming crabs. Such changes were highlighted by the overwhelming overabundance of V ibrio and a significant fluctuation in the gut bacteria including the bacteria with high relative abundance and especially those with low relative abundance. These findings reveal that crab vibriosis gradually develops with the infection time of V. alginolyticus and tightly relates to the dysbiosis of gut bacterial community structure. This work contributes to our appreciation of the importance of the balance of gut bacterial community structure in maintaining the health of crustaceans.

Alterations in gut microbiota are related to metabolite profiles in spinal cord injury

Studies have shown that gut microbiota metabolites can enter the central nervous system via the blood-spinal cord barrier and cause neuroinflammation, thus constituting secondary injury after spinal cord injury. To investigate the correlation between gut microbiota and metabolites and the possible mechanism underlying the effects of gut microbiota on secondary injury after spinal cord injury, in this study, we established mouse models of T8–T10 traumatic spinal cord injury. We used 16 S rRNA gene amplicon sequencing and metabolomics to reveal the changes in gut microbiota and metabolites in fecal samples from the mouse model. Results showed a severe gut microbiota disturbance after spinal cord injury, which included marked increases in pro-inflammatory bacteria, such as Shigella, Bacteroides, Rikenella, Staphylococcus, and Mucispirillum and decreases in anti-inflammatory bacteria, such as Lactobacillus, Allobaculum, and Sutterella. Meanwhile, we identified 27 metabolites that decreased and 320 metabolites that increased in the injured spinal cord. Combined with pathway enrichment analysis, five markedly differential amino acids(L-leucine, L-methionine, L-phenylalanine, L-isoleucine and L-valine) were screened out, which play a pivotal role in activating oxidative stress and inflammatory responses following spinal cord injury. Integrated correlation analysis indicated that the alteration of gut microbiota was related to the differences in amino acids, which suggests that disturbances in gut microbiota might participate in the secondary injury through the accumulation of partial metabolites that activate oxidative stress and inflammatory responses. Findings from this study provide a new theoretical basis for improving the secondary injury after spinal cord injury through fecal microbial transplantation.

Mucosa-associated bacteria in two middle-aged women diagnosed with collagenous colitis

AIM:To characterize the colon microbiota in two women histologically diagnosed with collagenous colitis using a culture-independent method.METHODS:Biopsies were taken from the ascending colon and the total DNA was extracted.Universal bacterial primers were used to amplify the bacterial 16S rRNA genes.The amplicons were then cloned into competent Escherichia coli cells.The clones were sequenced and identified by comparison to known sequences.RESULTS:The clones could be divided into 44 different phylotypes.The microbiota was dominated by Firmicutes and Bacteroidetes.Seven phylotypes werefound in both patients and constituted 47.5% of the total number of clones.Of these,the most dominating were clones similar to Bacteroides cellulosilyticus,Bacteroides caccae,Bacteroides thetaiotaomicron,Bacteroides uniformis and Bacteroides dorei within Bacteroidetes.Sequences similar to Faecalibacterium prausnitzii and Clostridium citroniae were also found in both patients.CONCLUSION:A predominance of potentially pathogenic Bacteroides spp.,and the presence of clones showing similarity to Clostridium clostridioforme were found but the overall colon microbiota showed similarities to a healthy one.Etiologies for collagenous colitis other than an adverse bacterial flora must also be considered.

Influence of group B streptococcus and vaginal cleanliness on the vaginal microbiome of pregnant women

BACKGROUND The vaginal microbiome plays a critical role in the health of pregnant women and their newborns.Group B Streptococcus(GBS)and vaginal cleanliness significantly affect the vaginal microecosystem and are closely associated with vaginal diseases.AIM To explore the effects of GBS status and vaginal cleanliness on vaginal microecosystems.METHODS We collected 160 vaginal swabs from pregnant women and divided them into the following four groups based on GBS status and vaginal cleanliness:GBS-positive+vaginal cleanliness I–II degree,GBS-negative+vaginal cleanliness I–II degree,GBS-positive+vaginal cleanliness III–IV degree,and GBS-negative+vaginal cleanliness III–IV degree.Samples were subjected to 16S rRNA gene amplicon sequencing.RESULTS Alpha diversity analysis showed that the Shannon index did not significantly differ between the four groups.We identified significant variation in taxa abundance between the GBS-positive and GBS-negative groups and between the vaginal cleanliness I–II degree and III–IV degree groups.Principal coordinate analysis and non-metric multidimensional scaling analysis further confirmed the microbial diversity of the four groups.Moreover,the linear discriminant analysis demonstrated that Lactobacillus jensenii and Actinobacteria were strongly associated with GBS-positive status,and Lactobacillus iners,Lactobacillaceae,Lactobacillus,Lactobacillales,Bacilli and Firmicutes were closely correlated with GBS-negative status.CONCLUSION GBS status and vaginal cleanliness significantly affect vaginal microbiome differences in pregnant women.Our findings provide instructional information for clinical antibiotic treatment in pregnant women with different GBS statuses and vaginal cleanliness degrees.

Sarcopenia and gut microbiota alterations in patients with hematological diseases before and after hematopoietic stem cell transplantation

Objective: The aim of this study was to investigate the prevalence of sarcopenia(SP) and its relationship with gut microbiota alterations in patients with hematological diseases before and after hematopoietic stem cell transplantation(HSCT).Methods: A total of 108 patients with various hematological disorders were selected from Peking University People’s Hospital. SP was screened and diagnosed based on the 2019 Asian Sarcopenia Diagnosis Strategy. Physical measurements and fecal samples were collected, and 16S rRNA gene sequencing was conducted. Alpha and beta diversity analyses were performed to evaluate gut microbiota composition and diversity.Results: After HSCT, significant decreases in calf circumference and body mass index(BMI) were observed,accompanied by a decline in physical function. Gut microbiota analyses revealed significant differences in the relative abundance of Enterococcus, Bacteroides, Blautia and Dorea species before and after HSCT(P<0.05). Before HSCT, sarcopenic patients had lower Dorea levels and higher Phascolarctobacterium levels than non-sarcopenia patients(P<0.01). After HSCT, no significant differences in species abundance were observed. Alpha diversity analysis showed significant differences in species diversity among the groups, with the highest diversity in the postHSCT 90-day group and the lowest in the post-HSCT 30-day group. Beta diversity analysis revealed significant differences in species composition between pre-and post-HSCT time points but not between SP groups. Linear discriminant analysis effect size(LEfSe) identified Alistipes, Rikenellaceae, Alistipes putredinis, Prevotellaceae defectiva and Blautia coccoides as biomarkers for the pre-HSCT sarcopenia group. Functional predictions showed significant differences in anaerobic, biofilm-forming and oxidative stress-tolerant functions among the groups(P<0.05).Conclusions: This study demonstrated a significant decline in physical function after HSCT and identified potential gut microbiota biomarkers and functional alterations associated with SP in patients with hematological disorders. Further research is needed to explore the underlying mechanisms and potential therapeutic targets.

Response of Heterotrophic Bacteria Abundance and Community Structure to Asian Dust Addition in the Oligotrophic Northwest Pacific Ocean

The dust storms from the continent usually affect the abundance and diversity of planktons by supplying trace elements. As such, the response of heterotrophic planktonic bacteria to dusts, nutrients(i.e., nitrogen and phosphorus) or ferrous dosages was investigated in the Kuroshio Extension region of the Northwest Pacific Ocean(NWPO) through on-board incubation experiments during an oceanographic survey in spring 2014. The flow cytometry and 16S rRNA high-throughput sequencing methods were applied to explore the abundance and community structure of bacteria, and the percentage of high nucleic acid bacteria(HNA%). The results showed that the heterotrophic bacteria abundance was low(average 2.55×10^5 cells mL^-1) and subjected to both nitrogen(N) and ferrous(Fe) limitation. Sand-dust deposition observably promoted the activity of heterotrophic planktonic bacteria. The maximum abundance of heterotrophic bacteria was 6.98×10^5 cells mL^-1 in the dust-dosage group, which was 44% higher than the control(P < 0.05). The HNA% in the dust-dosage group was 1.37 times higher than the control(P < 0.05). The activation mechanism was mainly related to the dissolution of N and Fe in the dusts. The relative abundance of genus Winogradskyella was significantly increased by dust deposition while the relative abundance of the genera Tenacibaculum and Hyphomonas was decreased. These variations of bacterial community structure were ascribed to the dissolution of nutrients N and P. Comparing the results of different experimental groups, this study concluded that dust storm improved the abundance of heterotrophic bacteria by dissolution of N and Fe.

Distribution of Bacterial Communities in Petroleum-Contaminated Soils from the Dagang Oilfield, China

Diversity in bacterial communities was investigated along a petroleum hydrocarbon content gradient(0-0.4043 g/g)in surface(5-10 cm)and subsurface(35-40 cm)petroleum-contaminated soil samples from the Dagang Oilfield,China.Using 16S rRNA Illumina high-throughput sequencing technology and several statistical methods,the bacterial diversity of the soil was studied.Subsequently,the environmental parameters were measured to analyze its relationship with the community variation.Nonmetric multidimensional scaling and analysis of similarities indicated a significant difference in the structure of the bacterial community between the nonpetroleum-contaminated surface and subsurface soils,but no differences were observed in different depths of petroleum-contaminated soil.Meanwhile,many significant correlations were obtained between diversity in soil bacterial community and physicochemical properties.Total petroleum hydrocarbon,total organic carbon,and total nitrogen were the three important factors that had the greatest impacts on the bacterial community distribution in the long-term petroleum-contaminated soils.Our research has provided references for the bacterial community distribution along a petroleum gradient in both surface and subsurface petroleum-contaminated soils of oilfield areas.

Ganjiang granule regulates cecal microflora and serum biochemical components in a rat model of constipation-predominant irritable bowel syndrome

Objective:To investigate the effects of Ganjiang granule(GG)on cecal microflora and serum biochemical components in rats with constipation-predominant irritable bowel syndrome(IBSeC).Methods:Twenty-four SpragueeDawley rats were randomly divided into four groups:control,model,GG,and probiotics.Rats in the model,GG,and probiotics groups received 3℃ tap water intragastrically;rats in the GG group were treated with GG;rats in the probiotics group were treated with probiotics.For all rats,enzyme-linked immunosorbent assay and colorimetry were used to assess serum biochemical components related to gastrointestinal function;16S rRNA high-throughput sequencing was used to analyze the cecal microflora.Results:The serum level of 5-hydroxytryptamine(HT)was higher in the model group than in the control group(Z=-2.082,P=.037).The model group exhibited changes in cecal microflora:the relative abundances of Lactobacillus decreased(Z=-2.882,P=.004)and Dorea increased(t=-3.030,P=.023),compared with the control group.The GG and probiotics groups exhibited normal serum levels of 5-HT.The GG and probiotics groups exhibited improved serum levels of gastrin;the probiotics group exhibited an improved serum level of vasoactive intestinal peptide.Compared with the model group,The GG group exhibited greater relative abundance of Ruminococcus(Z=-2.402,P=.016);the probiotics group exhibited greater relative abundance of SMB53(Z=-2.823,P=.005)and lower relative abundances of Desulfovibrio(Z=-2.823,P=.005)and Facklamia(Z=-2.608,P=.009).Conclusion:The effects of GG on IBS-C may be related to regulation of the serum level of 5-HT,as well as elevated relative abundance of beneficial bacteria in cecal microflora.

Study on Tongue Coating Microbiota in Patients with Atrophic Gastritis

Aims: To explore the tongue coating microbiota composition in patients with atrophic gastritis by using the 16S rRNA gene sequencing technology. Methods: The study included 29 atrophic gastritis patients and 29 age and gender-matched non-atrophic gastritis controls. By sequencing the V3-V4 region of the 16S rRNA, we investigated the microbial community structure and diversity on the tongue coating. Results: There was no significant difference in the microbial diversity on the tongue coating between the two groups. However, compared with the control, the atrophic gastritis group had a smaller number of operational taxonomic units (OTUs). At the class level, patients with atrophic gastritis had lower relative abundances of Betaproteobacteria and Spirochaetia than the control group. At the gene level, the abundance of Neisseria and Aggregatibacter in atrophic gastritis group had significantly decreased compared with control ones. Furthermore, functional prediction revealed that 24 metabolic pathways significantly differed between the two groups. Conclusions: Our findings provide novel evidence that tongue coating microbiota may be a biomarker for characterizing patient with atrophic gastritis, but its mechanism needs to be further elaborated.

Scanning electron microscopy coupled with energydispersive X-ray spectrometry for quick detection of sulfuroxidizing bacteria in environmental water samples

Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.