Isolation and characterization of bacteria associated with silkworm gut under antibiotic-treated larval feeding / Isolamento e caracterização de bactérias associadas ao trato intestinal do bicho-da-seda sob alimentação larval tratada com antibióticos

Abstract The impact of antibiotics on growth, cocoon production was assessed in addition to isolation and characterization of bacteria associated with silkworm gut of infected larvae. Larval rearing was maintained at recommended conditions of temperature and humidity. Silkworm larvae showing abnormal symptoms were collected from the control group and dissected for gut collection. Bacteria were isolated from the gut content by spreading on agar plates and incubated at 37 °C for 48 hrs. Bacterial identification and phylogenetic analysis were carried out by 16S rRNA gene sequencing. The isolated bacteria were subjected to antimicrobial susceptibility test (disc diffusion methods) by using Penicillin (10 µg/mL), Tetracycline (30 µg/mL), Amoxicillin (25 µg/mL), Ampicillin (10 µg/mL), and Erythromycin (15 µg/mL). All isolated strains showed positive results for the catalase test. We isolated and identified bacterial strains (n = 06) from the gut of healthy and diseased silkworm larvae. Based on the 16S rRNA gene sequence, isolated bacteria showed close relation with Serratia, Bacillus, and Pseudomonas spp. Notably, 83.3% of strains were resistant to Penicillin, Tetracycline, Amoxicillin, Ampicillin, and Erythromycin but 16.6% showed antibiotic susceptibility to the above-mentioned commonly used antibiotics. Silkworm larvae fed on penicillin-treated leaves showed significant improvement in larval weight, larval length, and cocoon production. Significantly higher larval weight (6.88g), larval length (5.84cm), and cocoon weight (1.33g) were recorded for larvae fed on leaves treated with penicillin as compared to other antibiotics. Isolated bacterial strains showed close relation with Serratia spp., Bacillus spp. and Pseudomonas spp.

Resumo O impacto dos antibióticos no crescimento e na produção do casulo foi avaliado, além do isolamento e caracterização das bactérias associadas ao intestino de larvas infectadas do bicho-da-seda. A criação das larvas foi mantida nas condições recomendadas de temperatura e umidade. As larvas do bicho-da-seda com sintomas anormais foram coletadas do grupo controle e dissecadas para coleta do intestino. As bactérias foram isoladas do conteúdo intestinal por espalhamento em placas de ágar e incubadas a 37° C durante 48 horas. A identificação bacteriana e a análise filogenética foram realizadas pelo sequenciamento do gene 16S rRNA. As bactérias isoladas foram submetidas a teste de sensibilidade antimicrobiana (métodos de difusão em disco) com penicilina (10 µg / mL), tetraciclina (30 µg / mL), amoxicilina (25 µg / mL), ampicilina (10 µg / mL) e eritromicina (15 µg / mL). Todas as cepas isoladas apresentaram resultados positivos para o teste da catalase. Isolamos e identificamos cepas bacterianas (n = 06) do intestino de larvas de bicho-da-seda saudáveis e doentes. Com base na sequência do gene 16S rRNA, as bactérias isoladas mostraram estreita relação com Serratia, Bacillus e Pseudomonas spp. Notavelmente, 83,3% das cepas eram resistentes a penicilina, tetraciclina, amoxicilina, ampicilina e eritromicina, mas 16,6% mostraram suscetibilidade aos antibióticos comumente usados mencionados acima. As larvas do bicho-da-seda alimentadas com folhas tratadas com penicilina apresentaram melhora significativa no peso larval, comprimento larval e produção de casulo. Peso larval significativamente maior (6,88g), comprimento larval (5,84cm) e peso do casulo (1,33g) foram registrados para larvas alimentadas com folhas tratadas com penicilina, em comparação com outros antibióticos. Cepas bacterianas isoladas mostraram estreita relação com Serratia spp., Bacillus spp. e Pseudomonas spp.

Study of the urban-impact on microbial communities and their virulence factors and antibiotic resistance genomes in the Nandu River, Haikou / 中华流行病学杂志

Objective: To explore the changes in bacterial community structure, antibiotic resistance genome, and pathogen virulence genome in river water before and after the river flowing through Haikou City and their transmission and dispersal patterns and to reveal anthropogenic disturbance's effects on microorganisms and resistance genes in the aquatic environment. Methods: The Nandu River was divided into three study areas: the front, middle and rear sections from the upstream before it flowed through Haikou City to the estuary. Three sampling sites were selected in each area, and six copies of the sample were collected in parallel at each site and mixed for 3 L per sample. Microbial community structure, antibiotic resistance, virulence factors, and mobile genetic elements were analyzed through bioinformatic data obtained by metagenomic sequencing and full-length sequencing of 16S rRNA genes. Variations in the distribution of bacterial communities between samples and correlation of transmission patterns were analyzed by principal co-ordinates analysis, procrustes analysis, and Mantel test. Results: As the river flowed through Haikou City, microbes' alpha diversity gradually decreased. Among them, Proteobacteria dominates in the bacterial community in the front, middle, and rear sections, and the relative abundance of Proteobacteria in the middle and rear sections was higher than that in the front segment. The diversity and abundance of antibiotic resistance genes, virulence factors, and mobile genetic elements were all at low levels in the front section and all increased significantly after flow through Haikou City. At the same time, horizontal transmission mediated by mobile genetic elements played a more significant role in the spread of antibiotic-resistance genes and virulence factors. Conclusions: Urbanization significantly impacts river bacteria and the resistance genes, virulence factors, and mobile genetic elements they carry. The Nandu River in Haikou flows through the city, receiving antibiotic-resistant and pathogen-associated bacteria excreted by the population. In contrast, antibiotic-resistant genes and virulence factors are enriched in bacteria, which indicates a threat to environmental health and public health. Comparison of river microbiomes and antibiotic resistance genomes before and after flow through cities is a valuable early warning indicator for monitoring the spread of antibiotic resistance.

A panel study on the effect of atmospheric PM2.5 exposure on the gut microbiome in healthy elderly people aged 60-69 years old / 中华预防医学杂志

Objective: To analyze the short-term effect of individual atmospheric PM2.5 exposure on the diversity, enterotype, and community structure of gut microbiome in healthy elderly people in Jinan, Shandong province. Methods: The present panel study recruited 76 healthy elderly people aged 60-69 years old in Dianliu Street, Lixia District, Jinan, Shandong Province, and followed them up five times from September 2018 to January 2019. The relevant information was collected by questionnaire, physical examination, precise monitoring of individual PM2.5 exposure, fecal sample collection and gut microbiome 16S rDNA sequencing. The Dirichlet multinomial mixtures (DMM) model was used to analyze the enterotype. Linear mixed effect model and generalized linear mixed effect model were used to analyze the effect of PM2.5 exposure on gut microbiome α diversity indices (Shannon, Simpson, Chao1, and ACE indices), enterotype and abundance of core species. Results: Each of the 76 subjects participated in at least two follow-up visits, resulting in a total of 352 person-visits. The age of 76 subjects was (65.0±2.8) years old with BMI (25.0±2.4) kg/m2. There were 38 males accounting for 50% of the subjects. People with an educational level of primary school or below accounted for 10.5% of the 76 subjects, and those with secondary school and junior college or above accounting for 71.1% and 18.4%. The individual PM2.5 exposure concentration of 76 subjects during the study period was (58.7±53.7) μg/m3. DMM model showed that the subjects could be divided into four enterotypes, which were mainly driven by Bacteroides, Faecalibacterium, Lachnospiraceae, Prevotellaceae, and Ruminococcaceae. Linear mixed effects model showed that different lag periods of PM2.5 exposure were significantly associated with a lower gut α diversity index (FDR<0.05 after correction). Further analysis showed that PM2.5 exposure was significantly associated with changes in the abundances of Firmicutes (Megamonas, Blautia, Streptococcus, etc.) and Bacteroidetes (Alistipes) (FDR<0.05 after correction). Conclusion: Short-term PM2.5 exposure is significantly associated with a decrease in gut microbiome diversity and changes in the abundance of several species of Firmicutes and Bacteroidetes in the elderly. It is necessary to further explore the underlying mechanisms between PM2.5 exposure and the gut microbiome, so as to provide a scientific basis for promoting the intestinal health of the elderly.

Saliva microbiota and metabolite in individuals with caries or periodontitis / 中华口腔医学杂志

Objective: To detect and analyze the characteristics of oral microbiota in species composition, function and metabolism among caries, periodontitis and oral healthy individuals, hunting for the microbiome-derived biomarkers with specificity and sensitivity to estimate the occurrence of these two diseases. Methods: Saliva samples were collected from 10 patients with high caries risk [decayed-missing-filled teeth (DMFT)≥6, HC group] in Department of Endodontics, 10 patients with periodontitis of grade Ⅱ A-Ⅲ C (PG group) in Department of Periodontology and 10 oral healthy individuals (HH group) from School of Stomatology, The Fourth Military Medical University during from March 2022 to June 2022. A baseline examination was conducted on all participants, including their oral conditions of caries and periodontal health. Metagenomic sequencing (Illumina PE150 platform) and liquid chromatography-mass spectrometry were used to detect microorganisms and their metabolites in the samples respectively. The sequencing data were analyzed to obtain the information of microbial taxonomic composition, functional genes and metabolites in each group of samples. The basic oral conditions and saliva samples of subjects in each group were evaluated and collected by the same professional endodontist. Results: There were no significant difference in baseline characteristics such as age and sex among the subjects in each group (P>0.05). DMFT in HC group (9.0±1.7) was significantly higher than that in HH group (0) and PG group (0) (F=243.00, P<0.001). Sequencing data analysis showed that the taxonomic compositions of salivary microbiota in each group were mainly Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria at the phylum level, and Streptococcus, Neisseria, Rothia, Prevotella at the genus level. Differential analysis showed that, compared with the HH group, HC group and PG group had significant differences in taxonomic composition (P<0.05), and the most significant among them was Prevotella. At the species level, Prevotella pallens was the most significant change in HC group, and Porphyromonas gingivalis in PG group. Metabolite analysis showed that there were significant differences in metabolites between HC group and PG group. The results showed that, compared with the HH group, the most significant metabolite change was 3-hydroxy-1, 5-diphenylpentan-1-one in HC group (P=0.001) and N1 acetylspermine in PG group (P=0.002) respectively. Compared with the PG group, the metabolite of HC group with the most significant difference is D-glucosamine 6-phosphate (P=0.006). The metabolism gene function analysis showed that, the enrichment of carbohydrate metabolism related genes was highest in HC group, followed with HH group, and it was lowest in PG group. In addition, compared with the HH group, the abundance of functional genes related to glucose metabolism, such as ABC transporter and phosphotransferase system, were significantly decreased in PG group (P<0.05), but significantly increased in HC group (P<0.05). Conclusions: There is a significant correlation between the alternation of carbohydrate metabolism of salivary microbiota with the occurrence of caries and periodontitis. In the future, Prevotella pallens and 3-hydroxy-1, 5-diphenylpentan-1-one may be the potential biomarkers of caries; while Porphyromonas gingivalis and N1 acetylspermine work in the predictions of periodontitis.

The structure and function analysis of bacterial community during aerobic composting of chicken manure / 生物工程学报

In order to determine the changes of bacterial community structure and function in the early, middle and late stage of aerobic composting of chicken manure, high-throughput sequencing and bioinformatics methods were used to determine and analyze the 16S rRNA sequence of samples at different stages of composting. Wayne analysis showed that most of the bacterial OTUs in the three composting stages were the same, and only about 10% of the operational taxonomic units (OTUs) showed stage specificity. The diversity indexes including Ace, Chao1 and Simpson showed a trend of increasing at first, followed by decreasing. However, there was no significant difference among different composting stages (P < 0.05). The dominant bacteria groups in three composting stages were analyzed at the phylum and genus levels. The dominant bacteria phyla at three composting stages were the same, but the abundances were different. LEfSe (line discriminant analysis (LDA) effect size) method was used to analyze the bacterial biological markers with statistical differences among three stages of composting. From the phylum to genus level, there were 49 markers with significant differences among different groups. The markers included 12 species, 13 genera, 12 families, 8 orders, 1 boundary, and 1 phylum. The most biomarkers were detected at early stage while the least biomarkers were detected at late stage. The microbial diversity was analyzed at the functional pathway level. The function diversity was the highest in the early stage of composting. Following the composting, the microbial function was enriched relatively while the diversity decreased. This study provides theoretical support and technical guidance for the regulation of livestock manure aerobic composting process.

Mechanism of Learning and Memory Impairment in Rats Exposed to Arsenic and/or Fluoride Based on Microbiome and Metabolome / 生物医学与环境科学（英文）

OBJECTIVE@#Arsenic (As) and fluoride (F) are two of the most common elements contaminating groundwater resources. A growing number of studies have found that As and F can cause neurotoxicity in infants and children, leading to cognitive, learning, and memory impairments. However, early biomarkers of learning and memory impairment induced by As and/or F remain unclear. In the present study, the mechanisms by which As and/or F cause learning memory impairment are explored at the multi-omics level (microbiome and metabolome).@*METHODS@#We stablished an SD rats model exposed to arsenic and/or fluoride from intrauterine to adult period.@*RESULTS@#Arsenic and/fluoride exposed groups showed reduced neurobehavioral performance and lesions in the hippocampal CA1 region. 16S rRNA gene sequencing revealed that As and/or F exposure significantly altered the composition and diversity of the gut microbiome，featuring the Lachnospiraceae_NK4A136_group, Ruminococcus_1, Prevotellaceae_NK3B31_group, [Eubacterium]_xylanophilum_group. Metabolome analysis showed that As and/or F-induced learning and memory impairment may be related to tryptophan, lipoic acid, glutamate, gamma-aminobutyric acidergic (GABAergic) synapse, and arachidonic acid (AA) metabolism. The gut microbiota, metabolites, and learning memory indicators were significantly correlated.@*CONCLUSION@#Learning memory impairment triggered by As and/or F exposure may be mediated by different gut microbes and their associated metabolites.

Application of emerging technologies for gut microbiome research

Microbiome is associated with a wide range of diseases. The gut microbiome is also a dynamic reflection of health status, which can be modified, thus representing great potential to exploit the mechanisms that influence human physiology. Recent years have seen a dramatic rise in gut microbiome studies, which has been enabled by the rapidly evolving high-throughput sequencing methods (i.e. 16S rRNA sequencing and shotgun sequencing). As the emerging technologies for microbiome research continue to evolve (i.e. metatranscriptomics, metabolomics, culturomics, synthetic biology), microbiome research has moved beyond phylogenetic descriptions and towards mechanistic analyses. In this review, we highlight different approaches to study the microbiome, in particular, the current limitations and future promise of these techniques. This review aims to provide clinicians with a framework for studying the microbiome, as well as to accelerate the adoption of these techniques in clinical practice.

Electro-acupuncture promotes gut motility and alleviates functional constipation by regulating gut microbiota and increasing butyric acid generation in mice / 中西医结合学报

OBJECTIVE@#Abnormalities in the gut microbiota and intestinal short-chain fatty acid (SCFA) levels are implicated in the pathogenesis of functional constipation (FC). Electro-acupuncture (EA) has been shown to improve constipation-related symptoms and rebalance the gut microbiota. However, it is currently unknown whether the gut microbiota is a key mechanistic target for EA or how EA promotes gut motility by regulating the gut microbiota and SCFAs. Therefore, we assessed the effects of EA in FC mice and pseudo-germfree (PGF) mice to address these questions.@*METHODS@#Forty female Kunming mice were randomly separated into a normal control group (n = 8), an FC group (n = 8), an FC + EA group (n = 8), a PGF group (n = 8) and a PGF + EA group (n = 8). The FC group and FC + EA group were treated with diphenoxylate to establish the FC model; the PGF group and PGF + EA group were given an antibiotic cocktail to initiate the PGF model. After maintaining the model for 14 d, mice in the FC + EA and PGF + EA groups received EA stimulation at the ST25 and ST37 acupoints, once a day, 5 times per week, for 2 weeks. Fecal parameters and intestinal transit rate were calculated to assess the efficacy of EA on constipation and gastrointestinal motility. Colonic contents were used to quantify gut microbial diversity using 16S rRNA sequencing, and measure SCFA concentrations using gas chromatography-mass spectrometry.@*RESULTS@#EA significantly shortened the first black stool defecation time (P < 0.05) and increased the intestinal transit rate (P < 0.01), and fecal pellet number (P < 0.05), wet weight (P < 0.05) and water content (P < 0.01) over 8 h, compared with the FC group, showing that EA promoted gut motility and alleviated constipation. However, EA treatment did not reverse slow-transit colonic motility in PGF mice (P > 0.05), demonstrating that the gut microbiota may play a mechanistic role in the EA treatment of constipation. In addition, EA treatment restored the Firmicutes to Bacteroidetes ratio and significantly increased butyric acid generation in FC mice (P < 0.05), most likely due to the upregulation of Staphylococcaceae microorganisms (P < 0.01).@*CONCLUSION@#EA-mediated resolution of constipation occurs through rebalancing the gut microbiota and promoting butyric acid generation. Please cite this article as: Xu MM, Guo Y, Chen Y, Zhang W, Wang L, Li Y. Electro-acupuncture promotes gut motility and alleviates functional constipation by regulating gut microbiota and increasing butyric acid generation in mice. J Integr Med. 2023; Epub ahead of print.

Anti-obesity and Gut Microbiota Modulation Effect of Astragalus Polysaccharides Combined with Berberine on High-Fat Diet-Fed Obese Mice / 中国结合医学杂志

OBJECTIVE@#To investigate whether astragalus polysaccharides (APS) combined with berberine (BBR) can reduce high-fat diet (HFD)-induced obesity in mice.@*METHODS@#Except for normal mice, 32 HFD-induced obese mice were randomized into HFD, APS (1,000 mg/kg APS), BBR (200 mg/kg BBR), and APS plus BBR (1,000 mg/kg APS plus 200 mg/kg BBR) groups, respectively. After 6-week treatment (once daily by gavage), the obesity phenotype and pharmacodynamic effects were evaluated by histopathological examination of epididymal fat, liver, and colon using hematoxylin-eosin staining and serum biochemical analyses by an automated chemistry analyzer. The feces were collected at the 12 th week, and taxonomic and functional profiles of gut microbiota were analyzed by 16S ribosomal ribonucleic acid (16S rRNA) sequencing.@*RESULTS@#Compared with HFD group, the average body weight of APS plus BBR group was decreased (P<0.01), accompanied with the reduced fat accumulation, enhanced colonic integrity, insulin sensitivity and glucose homeostasis (P<0.05 or P<0.01). Importantly, APS combined with BBR treatment was more effective than APS or BBR alone in improving HFD-induced insulin resistance (P<0.05 or P<0.01). 16S rRNA sequence-based analysis of fecal samples demonstrated that APS combined with BBR treatment exhibited a better impact on HFD-induced gut microbiota dysbiosis, exclusively via the enriched abundances of Bacteroides, which corresponded to the large increase of predicted bacterial genes involved in carbohydrate metabolism.@*CONCLUSION@#APS combined with BBR may synergistically reduce obesity and modulate the gut microbiota in HFD-fed mice.

Intestinal and pharyngeal microbiota in early neonates: an analysis based on high-throughput sequencing / 中国当代儿科杂志

OBJECTIVES@#To investigate the distribution characteristics and correlation of intestinal and pharyngeal microbiota in early neonates.@*METHODS@#Full-term healthy neonates who were born in Shanghai Pudong New Area Maternal and Child Health Hospital from September 2021 to January 2022 and were given mixed feeding were enrolled. The 16S rRNA sequencing technique was used to analyze the stool and pharyngeal swab samples collected on the day of birth and days 5-7 after birth, and the composition and function of intestinal and pharyngeal microbiota were analyzed and compared.@*RESULTS@#The diversity analysis showed that the diversity of pharyngeal microbiota was higher than that of intestinal microbiota in early neonates, but the difference was not statistically significant (P>0.05). On the day of birth, the relative abundance of Proteobacteria in the intestine was significantly higher than that in the pharynx (P<0.05). On days 5-7 after birth, the relative abundance of Actinobacteria and Proteobacteria in the intestine was significantly higher than that in the pharynx (P<0.05), and the relative abundance of Firmicutes in the intestine was significantly lower than that in the pharynx (P<0.05). At the genus level, there was no significant difference in the composition of dominant bacteria between the intestine and the pharynx on the day of birth (P>0.05), while on days 5-7 after birth, there were significant differences in the symbiotic bacteria of Streptococcus, Staphylococcus, Rothia, Bifidobacterium, and Escherichia-Shigella between the intestine and the pharynx (P<0.05). The analysis based on the database of Clusters of Orthologous Groups of proteins showed that pharyngeal microbiota was more concentrated on chromatin structure and dynamics and cytoskeleton, while intestinal microbiota was more abundant in RNA processing and modification, energy production and conversion, amino acid transport and metabolism, carbohydrate transport and metabolism, coenzyme transport and metabolism, and others (P<0.05). The Kyoto Encyclopedia of Genes and Genomes analysis showed that compared with pharyngeal microbiota, intestinal microbiota was more predictive of cell motility, cellular processes and signal transduction, endocrine system, excretory system, immune system, metabolic diseases, nervous system, and transcription parameters (P<0.05).@*CONCLUSIONS@#The composition and diversity of intestinal and pharyngeal microbiota of neonates are not significantly different at birth. The microbiota of these two ecological niches begin to differentiate and gradually exhibit distinct functions over time.

The influence of primer choice on archaeal phylogenetic analyses based on 16S rRNA gene PCR / A influência da escolha de iniciadores na filogenia de Archaea em ensaios de PCR para o gene rRNA 16S

Abstract Polymerase chain reaction (PCR) assays targeting 16S rRNA genes followed by DNA sequencing are still important tools to characterize microbial communities present in environmental samples. However, despite the crescent number of deposited archaeal DNA sequences in databases, until now we do not have a clear picture of the effectiveness and specificity of the universal primers widely used to describe archaeal communities from different natural habitats. Therefore, in this study, we compared the phylogenetic profile obtained when Cerrado lake sediment DNA samples were submitted to 16S rDNA PCR employing three Archaea-specific primer sets commonly used. Our findings reveal that specificity of primers differed depending on the source of the analyzed DNA. Furthermore, archaeal communities revealed by each primer pair varied greatly, indicating that 16S rRNA gene primer choice affects the community profile obtained, with differences in both taxon detection and operational taxonomic unit (OTU) estimates.

Resumo A amplificação de genes que codificam o rRNA 16S por reação em cadeia da polimerase (PCR) e o seu subsequente sequenciamento consistem em uma ferramenta importante na caracterização de comunidades microbianas presentes em amostras ambientais. No entanto, apesar do crescente número de sequências de DNA de Archaea depositadas em bancos de dados, a especificidade e efetividade dos iniciadores de PCR descritos como universais e amplamente utilizados na descrição desse grupo ainda não está clara. Neste estudo foram comparados os perfis filogenéticos de comunidades de arqueias obtidos a partir amostras de DNA de sedimentos lacustres do Cerrado submetidas a ensaios de PCR empregando três pares de iniciadores específicos para Archaea, comumente utilizados neste tipo de estudo. Nossos resultados indicam que as comunidades de arqueias detectadas com cada par de iniciadores apresentaram grande variação filogenética, sugerindo que a escolha de iniciadores dirigidos ao gene de rRNA 16S tem efeito significativo no perfil da comunidade descrita, com diferenças tanto em relação aos táxons detectados, como nas estimativas de unidades taxonômicas operacionais (OTU).

Isolation and screening of chromium resistant bacteria from industrial waste for bioremediation purposes / Isolamento e triagem de bactérias resistentes ao cromo de resíduos industriais para fins de biorremediação

Abstract Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (24˚52ʹ46.0ʺN 66˚59ʹ25.7ʺE and 24˚48ʹ37.5ʺN 67˚06ʹ52.6ʺE). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment.

Resumo O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (24˚52'46,0"N 66˚59'25,7"E e 24˚48'37,5"N 67˚06'52,6"E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30 ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.

Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico / Identificação por técnicas moleculares de bactérias halofílicas que produzem enzimas importantes em área intocada de Campeche, México

Abstract Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.

Resumo Isla Arena está localizada na coordenada 20°70'N - 90°45'W, de Campeche, México. Nesses estuários, o oceano se mistura com a água doce e os ecossistemas se concentram onde proliferam petenos e flamingos rosa. Crustáceos e moluscos abundam no mar. Apesar de sua enorme riqueza marinha, não há estudos realizados sobre a presença de microrganismos halofílicos nessas águas. Neste trabalho, a diversidade e estrutura da comunidade microbiana foram investigadas através de uma abordagem metagenômica e corroboradas para o sequenciamento de genes 16S rRNA. Verificou-se que o filo Fimicutes predomina com mais de 50%, quase na mesma proporção da classe Bacilli e com quase 41% de abundância relativa da ordem Bacillales. Os resultados do sequenciamento mostraram que uma das amostras apresentou alto percentual de similaridade (99,75%) pelo programa Nucleotide BLAST com um microrganismo peculiar: Bacillus subtilis. Nossos resultados demonstram que B. subtilis pode ser uma fonte eficiente de proteases, lipases e celulases, provenientes de comunidades microbianas halofílicas localizadas em áreas pouco exploradas.

Assessment of zinc solubilization potential of zinc-resistant Pseudomonas oleovorans strain ZSB13 isolated from contaminated soil / Avaliação do potencial de solubilização do zinco da cepa ZSB13 de Pseudomonas oleovorans resistente ao zinco isolada de solo contaminado

Abstract Zinc is an essential micronutrient that is required for optimum plant growth. It is present in soil in insoluble forms. Bacterial solubilization of soil unavailable form of Zn into available form, is an emerging approach to alleviate the Zn deficiency for plants and human beings. Zinc solubilizing bacteria (ZSB) could be a substitute for chemical Zn fertilizer. The present study aimed to isolate and characterize bacterial species from the contaminated soil and evaluate their Zn solubilizing potential. Zn resistant bacteria were isolated and evaluated for their MIC against Zn. Among the 13 isolated bacterial strains ZSB13 showed maximum MIC value upto 30mM/L. The bacterial strain with the highest resistance against Zn was selected for further analysis. Molecular characterization of ZSB13 was performed by 16S rRNA gene amplification which confirmed it as Pseudomonas oleovorans. Zn solubilization was determined through plate assay and broth medium. Four insoluble salts (zinc oxide (ZnO), zinc carbonate (ZnCO3), zinc sulphite (ZnS) and zinc phosphate (Zn3(PO4)2) were used for solubilization assay. Our results shows 11 mm clear halo zone on agar plates amended with ZnO. Likewise, ZSB13 showed significant release of Zn in broth amended with ZnCO3 (17 and 16.8 ppm) and ZnO (18.2 ppm). Furthermore, Zn resistance genes czcD was also enriched in ZSB13. In our study, bacterial strain comprising Zn solubilization potential has been isolated that could be further used for the growth enhancement of crops.

Resumo O zinco é um micronutriente essencial necessário para o crescimento ideal das plantas. Ele está presente no solo em formas insolúveis. A solubilização bacteriana da forma indisponível de Zn no solo para a forma disponível é uma abordagem emergente para aliviar a deficiência de Zn em plantas e seres humanos. Bactérias solubilizadoras de zinco (ZSB) podem ser um substituto para fertilizantes químicos de Zn. O presente estudo teve como objetivo isolar e caracterizar espécies bacterianas de solo contaminado e avaliar seu potencial de solubilização de Zn. Bactérias resistentes ao Zn foram isoladas e avaliadas quanto ao seu MIC contra o Zn. Entre as 13 cepas bacterianas isoladas, ZSB13 apresentou valor máximo de MIC de até 30 mM/L. A cepa bacteriana com maior resistência ao Zn foi selecionada para análise posterior. A caracterização molecular de ZSB13 foi realizada por amplificação do gene 16S rRNA que o confirmou como Pseudomonas oleovorans. A solubilização do Zn foi determinada através de ensaio em placa e meio caldo. Quatro sais insolúveis (óxido de zinco (ZnO), carbonato de zinco (ZnCO3), sulfito de zinco (ZnS) e fosfato de zinco (Zn3 (PO4) 2) foram usados ​​para o ensaio de solubilização. Nossos resultados mostram uma zona de halo clara de 11 mm em placas de ágar corrigidas com ZnO. Da mesma forma, ZSB13 mostrou liberação significativa de Zn em caldo alterado com ZnCO3 (17 e 16,8 ppm) e ZnO (18,2 ppm). Além disso, os genes de resistência ao Zn czcD também foram enriquecidos em ZSB13. Em nosso estudo, a cepa bacteriana compreendendo potencial de solubilização de Zn foi isolada e poderia ser usada posteriormente para o aumento do crescimento de safras.

Gut dysbiosis, inflammation and type 2 diabetes in mice using synthetic gut microbiota from diabetic humans / Disbiose intestinal, inflamação e diabetes tipo 2 em camundongos usando microbiota intestinal sintética de humanos diabéticos

Abstract The study was aimed to assess impact of high fat diet (HFD) and synthetic human gut microbiota (GM) combined with HFD and chow diet (CD) in inducing type-2 diabetes (T2D) using mice model. To our knowledge, this is the first study using selected human GM transplantation via culture based method coupled dietary modulation in mice for in vivo establishment of inflammation leading to T2D and gut dysbiosis. Twenty bacteria (T2D1-T2D20) from stool samples of confirmed T2D subjects were found to be morphologically different and subjected to purification on different media both aerobically and anerobically, which revealed seven bacteria more common among 20 isolates on the basis of biochemical characterization. On the basis of 16S rRNA gene sequencing, these seven isolates were identified as Bacteroides stercoris (MT152636), Lactobacillus acidophilus (MT152637), Lactobacillus salivarius (MT152638), Ruminococcus bromii (MT152639), Klebsiella aerogenes (MT152640), Bacteroides fragilis (MT152909), Clostridium botulinum (MT152910). The seven isolates were subsequently used as synthetic gut microbiome (GM) for their role in inducing T2D in mice. Inbred strains of albino mice were divided into four groups and were fed with CD, HFD, GM+HFD and GM+CD. Mice receiving HFD and GM+modified diet (CD/HFD) showed highly significant (P<0.05) increase in weight and blood glucose concentration as well as elevated level of inflammatory cytokines (TNF-α, IL-6, and MCP-1) compared to mice receiving CD only. The 16S rRNA gene sequencing of 11 fecal bacteria obtained from three randomly selected animals from each group revealed gut dysbiosis in animals receiving GM. Bacterial strains including Bacteroides gallinarum (MT152630), Ruminococcus bromii (MT152631), Lactobacillus acidophilus (MT152632), Parabacteroides gordonii (MT152633), Prevotella copri (MT152634) and Lactobacillus gasseri (MT152635) were isolated from mice treated with GM+modified diet (HFD/CD) compared to strains Akkermansia muciniphila (MT152625), Bacteriodes sp. (MT152626), Bacteroides faecis (MT152627), Bacteroides vulgatus (MT152628), Lactobacillus plantarum (MT152629) which were isolated from mice receiving CD/HFD. In conclusion, these findings suggest that constitution of GM and diet plays significant role in inflammation leading to onset or/and possibly progression of T2D. .

Resumo O estudo teve como objetivo avaliar o impacto da dieta rica em gordura (HFD) e da microbiota intestinal humana sintética (GM) combinada com HFD e dieta alimentar (CD) na indução de diabetes tipo 2 (T2D) usando modelo de camundongos. Para nosso conhecimento, este é o primeiro estudo usando transplante de GM humano selecionado através do método baseado em cultura acoplada à modulação dietética em camundongos para o estabelecimento in vivo de inflamação que leva a T2D e disbiose intestinal. Vinte bactérias (T2D1-T2D20) de amostras de fezes de indivíduos T2D confirmados verificaram ser morfologicamente diferentes e foram submetidas à purificação em meios diferentes aerobicamente e anaerobicamente, o que revelou sete bactérias mais comuns entre 20 isolados com base na caracterização bioquímica. Com base no sequenciamento do gene 16S rRNA, esses sete isolados foram identificados como Bacteroides stercoris (MT152636), Lactobacillus acidophilus (MT152637), Lactobacillus salivarius (MT152638), Ruminococcus bromii (MT152639), Klebsiella aerogenides (MT152640), Bacteroides fragilis (MT152909), Clostridium botulinum (MT152910). Esses sete isolados foram, posteriormente, usados ​​como microbioma intestinal sintético (GM) por seu papel na indução de T2D em camundongos. Linhagens consanguíneas de camundongos albinos foram divididas em quatro grupos e foram alimentadas com CD, HFD, GM + HFD e GM + CD. Camundongos que receberam a dieta modificada com HFD e GM + (CD / HFD) mostraram um aumento altamente significativo (P < 0,05) no peso e na concentração de glicose no sangue, bem como um nível elevado de citocinas inflamatórias (TNF-α, IL-6 e MCP-1) em comparação com os ratos que receberam apenas CD. O sequenciamento do gene 16S rRNA de 11 bactérias fecais obtidas de três animais selecionados aleatoriamente de cada grupo revelou disbiose intestinal em animais que receberam GM. Cepas bacterianas, incluindo Bacteroides gallinarum (MT152630), Ruminococcus bromii (MT152631), Lactobacillus acidophilus (MT152632), Parabacteroides gordonii (MT152633), Prevotella copri (MT152634) e Lactobacillus Gasseri (MT152635D), foram tratadas com dieta modificada / CD) em comparação com as linhagens Akkermansia muciniphila (MT152625), Bacteriodes sp. (MT152626), Bacteroides faecis (MT152627), Bacteroides vulgatus (MT152628), Lactobacillus plantarum (MT152629), que foram isoladas de camundongos recebendo CD / HFD. Em conclusão, esses resultados sugerem que a constituição de GM e dieta desempenham papel significativo na inflamação levando ao início ou/e possivelmente à progressão de T2D.

Changes of gut microflora in newly diagnosed IgA nephropathy patients and its correlation with clinical risk factors / 北京大学学报(医学版)

OBJECTIVE@#To investigate the gut microbiota in newly diagnosed IgA nephropathy patients with chronic kidney disease (CKD) stages 1-2 and the association between the gut microbiota and the clinical risk factors of IgA nephropathy.@*METHODS@#Fresh fecal samples were collected from nineteen newly diagnosed IgA nephropathy patients with CKD stages 1-2 and fifteen age- and sex-matched healthy controls. Fecal bacterial DNA was extracted and microbiota composition were characterized using 16S ribosomal RNA (16S rRNA) high-throughput sequencing for the V3-V4 region. The Illumina Miseq platform was used to analyze the results of 16S rRNA high-throughput sequencing of fecal flora. At the same time, the clinical risk factors of IgA nephropathy patients were collected to investigate the association between the gut microbiota and the clinical risk factors.@*RESULTS@#(1) At the phylum level, the abundance of Bacteroidetes was significantly reduced (P=0.046), and the abundance of Actinobacteria was significantly increased (P=0.001). At the genus level, the abundance of Escherichia-Shigella, Bifidobacte-rium, Dorea and others were significantly increased (P < 0.05). The abundance of Lachnospira, Coprococcus_2 and Sutterella was significantly reduced (P < 0.05). (2) There was no significant difference in the abundance of gut microbiota between the newly diagnosed IgA nephropathy patients and the healthy control group (P>0.05), but there were differences in the structure of the gut microbiota between the two groups. The results of LEfSe analysis showed that there were 16 differential bacteria in the newly diagnosed IgA nephropathy patients and healthy controls. Among them, the abundance of the newly diagnosed IgA nephropathy patients was increased in Enterobacteriales, Actinobacteria, Escherichia-Shigella, etc. The healthy control group was increased in Bacteroidetes and Lachnospira. (3) The result of redundancy analysis (RDA) showed that Bifidobacterium was positively correlated with serum IgA levels, 24-hour urinary protein levels and the presence of hypertension. Lachnoclostridium was positively correlated with the presence of hypertension. Escherichia-Shigella was positively correlated with urine red blood cells account. Bifidobacterium was positively correlated with the proliferation of capillaries. Faecalibacterium was positively correlated with cell/fibrocytic crescents. Ruminococcus_2 was positively correlated with mesangial cell proliferation, glomerular segmental sclerosis and renal tubular atrophy/interstitial fibrosis.@*CONCLUSION@#The gut microbiota in the newly diagnosed IgA nephropathy patients with CKD stages 1-2 is different from that of the healthy controls. Most importantly, some gut bacteria are related to the clinical risk factors of IgA nephropathy. Further research is needed to understand the potential role of these bacteria in IgA nephropathy.

Profiles and differences of submucosal microbial in peri-implantitis and health implants: A cross-sectional study / 北京大学学报(医学版)

OBJECTIVE@#To describe the submucosal microbial profiles of peri-implantitis and healthy implants, and to explore bacteria that might be correlated with clinical parameters.@*METHODS@#In the present cross-sectional study, 49 patients were recruited. Each patient contributed with one implant, submucosal biofilms were collected from 20 healthy implants and 29 implants with peri-implantitis. DNA was extracted and bacterial 16S ribosomal RNA (16S rRNA) genes were amplified. Submucosal biofilms were analyzed using 16S rRNA sequencing at Illumina MiSeq platform. Differences between the groups were determined by analyzing α diversity, microbial component and microbial structure. The potential correlation between the bacteria with pocket probing depth (PPD) of peri-implant calculated by Spearman correlation analysis.@*RESULTS@#The α diversity of submucosal microbial of health group was significantly lower than that in peri-implantitis group (Chao1 index: 236.85±66.13 vs. 150.54±57.43, P < 0.001; Shannon index: 3.42±0.48 vs. 3.02±0.65, P=0.032). Principal coordinated analysis showed that the submucosal microbial structure had significant difference between healthy and peri-implantitis groups [R2=0.243, P=0.001, analysis of similarities (ANOSIM)]. Compared with healthy implants, relative abundance of periodontal pathogens were higher in peri-implantitis, including members of the red complex (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola) and some members of orange complex (Precotella intermedia, Eubacterium nodatum, Parvimonas micra), as well as some new periodontal pathogens, such as Fillifactor alocis, Fretibacterium fastidiosum, Desulfobulbus sp._HMT_041, and Porphyromonas endodontalis. Spearman correlation analysis revealed that the relative abundance of Treponema denticola (r=0.686, P < 0.001), Tannerella forsythia (r=0.675, P < 0.001), Fretibacterium sp. (r=0.671, P < 0.001), Desulfobulbus sp._HMT_041 (r=0.664, P < 0.001), Filifactor alocis (r=0.642, P < 0.001), Fretibacterium fastidiosum (r=0.604, P < 0.001), Porphyromonas gingivalis (r=0.597, P < 0.001), Porphyromonas endodontalis (r=0.573, P < 0.001) were positive correlated with PPD. While the relative abundance of Rothia aeria (r=-0.615, P < 0.001) showed negatively correlation with PPD.@*CONCLUSION@#Marked differences were observed in the microbial profiles of healthy implants and peri-implantitis. The members of red and orange complex as well as some new periodontal pathogens seem to play an important role in peri-implant disease. Compared with healthy implants, the submucosal microbial of peri-implantitis were characterized by high species richness and diversity.

Determining the protective effects of Ma-Mu-Ran Antidiarrheal Capsules against acute DSS-induced enteritis using 16S rRNA gene sequencing and fecal metabolomics / 中国天然药物

Ma-Mu-Ran Antidiarrheal Capsules (MMRAC) is traditional Chinese medicine that has been used to treat diarrhea caused by acute enteritis (AE) and bacillary dysentery in Xinjiang (China) for many years. However, the potential therapeutic mechanism of MMRAC for AE and its regulatory mechanism on host metabolism is unclear. This study used fecal metabolomics profiling with GC/MS and 16S rRNA gene sequencing analysis to explore the potential regulatory mechanisms of MMRAC on a dextran sulfate sodium salt (DSS)-induced mouse model of AE. Fecal metabolomics-based analyses were performed to detect the differentially expressed metabolites and metabolic pathways. The 16S rRNA gene sequencing analysis was used to assess the altered gut microbes at the genus level and for functional prediction. Moreover, Pearson correlation analysis was used to integrate differentially expressed metabolites and altered bacterial genera. The results revealed that six intestinal bacteria and seven metabolites mediated metabolic disorders (i.e., metabolism of amino acid, carbohydrate, cofactors and vitamins, and lipid) in AE mice. Besides, ten altered microbes mediated the differential expression of eight metabolites and regulated these metabolisms after MMRAC administration. Overall, these findings demonstrate that AE is associated with metabolic disorders and microbial dysbiosis. Further, we present that MMRAC exerts protective effects against AE by improving host metabolism through the intestinal flora.

Features of intestinal flora in children with food protein-induced proctocolitis based on high-throughput sequencing / 中国当代儿科杂志

OBJECTIVES@#To study the features of intestinal flora in children with food protein-induced proctocolitis (FPIP) by high-throughput sequencing.@*METHODS@#A total of 31 children, aged <6 months, who experienced FPIP after exclusive breastfeeding and attended the outpatient service of the Third Affiliated Hospital of Zunyi Medical University from October 2018 to February 2021 were enrolled as the FPIP group. Thirty-one healthy infants were enrolled as the control group. Fecal samples were collected to extract DNA for PCR amplification. High-throughput sequencing was used to perform a bioinformatics analysis of 16S rDNA V3-V4 fragments in fecal samples.@*RESULTS@#The diversity analysis of intestinal flora showed that compared with the control group, the FPIP group had a lower Shannon index for diversity (P>0.05) and a significantly higher Chao index for abundance (P<0.01). At the phylum level, the intestinal flora in both groups were composed of Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Compared with the control group, the FPIP group had a significant reduction in the composition ratio of Actinobacteria (P<0.001) and a significant increase in the composition ratio of Proteobacteria (P<0.05). At the genus level, the intestinal flora in the FPIP group were mainly composed of Escherichia, Clostridium, Enterococcus, Klebsiella, and Bifidobacterium, and the intestinal flora in the control group were mainly composed of Bifidobacterium and Streptococcus. Compared with the control group, the FPIP group had a significant reduction in the composition ratio of Bifidobacterium and Ruminococcus (P<0.05) and significant increases in the composition ratios of Clostridium and Shigella (P<0.05).@*CONCLUSIONS@#Compared with the control group, the FPIP group has a reduction in the diversity of intestinal flora and an increase in their abundance, and there are certain differences in several bacterial genera. These results suggest that changes in the composition of intestinal flora at genus level may play an important role in the development and progression of FPIP.

Change in intestinal flora after treatment in children with focal epilepsy / 中国当代儿科杂志

OBJECTIVES@#To study the difference in intestinal flora between children with focal epilepsy and healthy children and the change in intestinal flora after treatment in children with epilepsy.@*METHODS@#A total of 10 children with newly diagnosed focal epilepsy were recruited as the case group and were all treated with oxcarbazepine alone. Their clinical data were recorded. Fecal specimens before treatment and after 3 months of treatment were collected. Fourteen aged-matched healthy children were recruited as the control group. Total bacterial DNA was extracted from the fecal specimens for 16S rDNA sequencing and bioinformatics analysis.@*RESULTS@#After 3 months of carbamazepine treatment, the seizure frequency was reduced by >50% in the case group. At the phylum level, the abundance of Actinobacteria in the case group before treatment was significantly higher than that in the control group (P<0.05), and it was reduced after treatment (P<0.05). At the genus level, the abundances of Escherichia/Shigella, Streptococcus, Collinsella, and Megamonas in the case group before treatment were significantly higher than those in the control group (P<0.05), and the abundances of these bacteria decreased significantly after treatment (P<0.05).@*CONCLUSIONS@#There is a significant difference in intestinal flora between children with focal epilepsy and healthy children. Oxcarbazepine can significantly improve the symptoms and intestinal flora in children with epilepsy.