16S rRNA Analysis Research Articles

In vitro evaluation of the probiotic potential of Lactobacillus isolated from native swine manure.

Background and Aim:Using antimicrobials as a feed additive in swine production is prohibited because it is a major cause of the emergence of antimicrobial-resistant bacteria. Probiotics such as Lactobacillus spp. are an attractive alternative to reduce antimicrobial resistance and promote swine growth. This study aimed to evaluate the in vitro probiotic properties of Lactobacillus isolated from indigenous swine manure.Materials and Methods:A total of 30 fecal samples from healthy individual indigenous pigs were collected and isolated on de Man, Rogosa, and Sharpe agar. The preliminary screen identified candidates with antibacterial activity against six pathogens and >50% survival and tolerance to acid (pH 3.0) and 1% bile salt. Isolates that passed the initial screen will be tested for other probiotic properties.Results:Of the 314 isolates from 30 pig manure samples, 17 isolates satisfied all initial conditions for probiotic properties. Each isolate has unique, distinctive properties. Isolates B4, B5, B8, B17, B87, and B144 formed thick biofilms, whereas isolates B5, B8, and 27 adhered well to the intestinal wall and exhibited strong autoaggregation properties. Isolate B4 aggregated with Enterohemorrhagic Escherichia coli and Enteropathogenic E. coli. Tests in pH-adjusted cell-free medium indicated that the antibacterial activity resulted from bacterial acidification rather than bacteriocin formation. Sequence analysis (16S rRNA) revealed 16 of the isolates were Lactobacillus plantarum, and only one isolate was Lactobacillus salivarius.Conclusion:We isolated 17 Lactobacillus from swine manure and demonstrated that their probiotic properties might be useful as a probiotic cocktail for swine feed.

Comparative analysis of 16S rRNA based phylogeny, antibiotic susceptibility, and virulence traits of Arcobacter species recovered from domestic fowl and the Nile tilapia

Untreated poultry manure/droppings were used in integrated fish ponds as organic fertilizers. This process could put an additional complexity on the bacterial load within fish's ponds ecosystem. Arcobacter species is one of the most important food-borne zoonotic pathogens that infect humans, animals, fish, and fowl. This study aimed to examine if raw poultry manure could possibly enhance Arcobacter propagation among the cohabitant Nile tilapia. In addition, the comparative phenotypic and molecular characterizations among various Arcobacter spp. retrieved from two diverse animal hosts (the Nile tilapia and fowl) with special reference to antibiotic-resistant and virulence genes traits were also studied. Clinically, the examined Nile tilapias exhibited darkness, fin rot, and skin hemorrhages. Internally, the Nile tilapias displayed severe congestion in internal organs, catarrhal enteritis, and swollen gall bladder. The moribund chickens exhibited mild diarrhea, anorexia, and ruffled feathers. Internally, chickens displayed enlarged spleen and liver, enteritis, and kidney congestion. The bacterial colonies on Arcobacter selective agar appeared small and non-pigmented with an intact edge. The recovered bacterial isolates were identified as Arcobacter spp. depending on the phenotypic characters and PCR. Sequencing of 16S rRNA gene confirmed the identity of Arcobacter butzleri (A. butzleri), A. skirrowii, and A. cryaerophilus in both fish and fowl, while A. cloacae was confirmed in fish. PCR confirmed the occurrence of two virulence genes (pldA and tlyA) in most fish and chicken Arcobacter isolates. All chicken Arcobacter isolates showed resistance against ampicillin, ampicillin-sulbactam, and cefotaxime, and variable susceptibility to ciprofloxacin, aztreonam, imipenem, and amikacin. Fish Aeromonads were sensitive to ciprofloxacin, sulpha-trimethoprim, and amikacin.

Sex Differences in Gut Microbiome Dysbiosis between Individuals with or without Cardiovascular Disease

Cardiovascular disease (CVD), as one of the leading causes of death worldwide, represents various morbid conditions such as hypertension and atherosclerosis. As gut microbial dysbiosis has been reported in patients with different types of CVD, we previously analyzed large-scale gut microbiome data of CVD and non-CVD human subjects and reported a gut microbiome-based machine learning strategy for discriminating the CVD and non-CVD subjects. In this study, we further hypothesized that sex is a discriminative factor in gut microbiome-based classification of CVD and non-CVD. We analyzed 16S rRNA sequencing data of stool samples collected from 305 CVD males, 213 non-CVD males, 169 CVD females and 259 non-CVD females through the American Gut Project. We identified 62 differential bacterial taxa with a score of linear discriminant analysis effect size (LDA) more than 2.0 between the female CVD and non-CVD groups (Figure 1A), whereas 33 differential bacterial features (LDA > 2.0) between the male CVD and non-CVD groups (Figure 1B). Genera Bacteroides, Subdoligranulum and Citrobacter were found to be more abundant in female CVD patients, whereas Pseudomonas, Akkermansia, and Clostridium were more abundant in male CVD patients. Interestingly, Clostridium, which was previously reported to be associated with heart failure and cardiomyopathy, was the only bacterial taxa identified to be enriched in both male and female CVD groups, indicating clear sex differences in gut microbiome dysbiosis between individuals with or without CVD. As our previous work demonstrates the promising application of gut microbiome-based machine learning for the detection of CVD, the current study further reveals the importance of segregating sex as a discriminative feature for improving microbiome-based diagnostics of CVD.

Prevalence and Genetic Analysis of Chromosomal mcr-3/7 in Aeromonas From U.S. Animal-Derived Samples.

The prevalence of mcr-positive bacteria in 5,169 domestic animal-derived samples collected by USDA Food Safety and Inspection Service between October 2018 and May 2019 was investigated. A procedure including enriched broth culture and real-time PCR targeting mcr-1 to mcr-8 were used for the screening. Fifteen positive isolates were identified, including one plasmid-borne mcr-1-positive Escherichia coli strain, EC2492 (reported elsewhere) and 14 mcr-3/7-positive strains from poultry (1), catfish (2), and chicken rinse (11) samples, resulting in an overall prevalence of mcr-positive bacteria 0.29% in all meat samples tested. Analysis of 16S rRNA and whole genome sequences revealed that all 14 strains belonged to Aeromonas. Data from phylogenetic analysis of seven housekeeping genes, including gyrB, rpoD, gyrA, recA, dnaJ, dnaX, and atpD, indicated that nine strains belonged to Aeromonas hydrophila and five strains belonged to Aeromonas jandaei. Antimicrobial tests showed that almost all mcr-positive strains exhibited high resistance to colistin with MICs ≥ 128mg/L, except for one A. jandaei strain, which showed a borderline resistance with a MIC of 2 mg/L. A segment containing two adjacent mcr-3 and mcr-3-like genes was found in two A. hydrophila and one A. jandaei strains and a variety of IS-like elements were found in the flanking regions of this segment. A mcr-3-related lipid A phosphoethanolamine transferase gene was present in all 14 Aeromonas strains, while an additional mcr-7-related lipid A phosphoethanolamine transferase gene was found in 5 A. jandaei strains only. In addition to mcr genes, other antimicrobial resistance genes, including blaOXA–12/OXA–724, aqu-2, tru-1, cepS, cphA, imiH, ceph-A3, ant(3″)-IIa, aac(3)-Via, and sul1 were observed in chromosomes of some Aeromonas strains. The relative high prevalence of chromosome-borne mcr-3/7 genes and the close proximity of various IS elements to these genes highlights the need for continued vigilance to reduce the mobility of these colistin-resistance genes among food animals.

Characterization of ‘Candidatus Phytoplasma asteris’-related strain association with leaf yellowing of Wrightia antidysenterica (Arctic Snow) in Tripura, India

Wrightia antidysenterica is a small compact and evergreen ornamental shrub. Little leaf and yellowing symptoms were recorded on W. antidysenterica plants in June 2018 at College of Agriculture campus, Lembucherra, Tripura. The expected amplicons of ~1.25 kb and ~480 bp were obtained in symptomatic leaf samples with the phytoplasma specific universal 16S rRNA and secA gene primers. Sequence comparison analysis of 16S rRNA and secA gene confirmed the association of ‘Ca. P. asteris’-related strain. However, comparing the restriction profiles of 16S rRNA gene in virtual RFLP analysis revealed that the phytoplasma was a 16SrI group related strain. To our knowledge, this is the first report of phytoplasma association with W. antidysenterica little leaf and yellowing in world.

Performance of single-stage partial nitritation and anammox reactor treating low-phenol/ammonia ratio wastewater and analysis of microbial community structure.

Phenol and ammonia are common pollutants in many industrial wastewaters. The partial nitritation and anammox process is a very promisingtechnology for treating phenol-ammonia wastewater. This study was the first time to rapidly achieve the start-up and operation of the single-stage partial nitritation /anammox reactor treating phenol-ammonia wastewater. The optimized ratio of phenol and nitrogen (phenol/NH4 + -N=0.3) was set to start-up the reactor. After 60days of operation, the total nitrogen and COD removal efficiencies were around 73.0% and 79.5%, respectively. The activity of ammonium-oxidizing bacteria was291.1±3.0mg NH4 + -Ng-1 MLVSSd-1 and the specific anammox activity was 20.9±1.0mg NH4 + -Ng-1 MLVSSd-1 . The results indicated that the anammox bacteria had adapted to phenol condition and remained stable activity after the 60days' operation in the reactor. The sequence analysis of 16SrRNA showed that the microbial community structure evolved to a balanced distribution that the removals of phenol and ammonia could be achieved simultaneously. PRACTITIONER POINTS: Phenol/N ratio of 0.3 was set to start up the single-stage partial nitritation/anammox reactor. The single-stage partial nitritation /anammox reactor was rapidly started up when treating the phenol-ammonia wastewater. Total nitrogen removal rate and COD removal efficiencies could achieve to 73.0% and 79.5%, respectively. Microbial community structure evolved to stable distribution of which AOB, anammox bacteria, denitrification bacteria and heterotrophic nitrification bacteria coexisted.

Molecular identification of brinjal little leaf disease associated with Solanum melongena L. in Eastern Uttar Pradesh, India

Symptoms of little leaf were observed in brinjal plants variety VNR218 at five different locations near Gorakhpur, Deoria, Padrona, Pipraich and Kushinagar, Eastern Uttar Pradesh, India during 2018–2019. Ten symptomatic samples showing little leaf and stunted growth and three asymptomatic brinjal plants were collected during survey. Total genomic DNA was extracted from all the collected samples and primed with primers P1/P7 and R16F2n/R16R2. ~ 1280 bp amplicons were obtained from all the ten symptomatic brinjal plants. Expected size amplicons were also amplified from four BLL samples with primers specific to 16SrVI group of rp and secY genes. All the amplified products were sequenced and submitted to GenBank. On the basis of sequence comparison analysis of 16SrRNA, rp and secY gene showed 99–100% similarity with the ‘Candidatus Phytoplasma trifolii’ strain. Evolutionary and RFLP analysis also proved the association of 16SrVI-A group of phytoplasma with brinjal little leaf Gorakhpur isolate. Thus, the association of 16SrVI group and A subgroup phytoplasma with brinjal little leaf Gorakhpur isolate is the first report from Eastern Uttar Pradesh, India.

Coral microbiome changes over the day–night cycle

Coral-associated microbiomes play important roles in host health and metabolism. It is therefore critical to understand the factors that shape microbiome taxonomic composition and function. Little is known about the stability of coral microbiomes over hourly fluctuations in environmental conditions. For parameters such as temperature and pH, the magnitude of day–night fluctuations can exceed those observed in mean values over seasons, especially on shallow reefs. Such short-term heterogeneity can affect longer term trends, possibly by influencing the extent to which corals acclimate to stress and increase resilience. This study examined diel dynamics of microbiomes (Bacteria and Archaea) in three species of stony coral (Porites lutea, Porites cylindrica, and Pocillopora damicornis) from a shallow reef in Mo’orea (French Polynesia). We assessed microbiome composition and relative transcriptional activity by analyzing 16S rRNA gene and transcript sequences from six timepoints over 48 h for each species. Both the composition and transcription of microbiome members changed significantly over the diel cycle. Most changes did not exhibit clear diel periodicity but were instead stochastic, a pattern potentially influenced also by microspatial variation within a coral colony. However, a subset of taxa, notably the dinoflagellate-associated bacterium Porticoccus and bacteria of the ubiquitous coral-associated Endozoicomonas genus, exhibited cyclic changes in relative frequency over the 2 d sampling period in the DNA dataset of Porites lutea. These patterns raise the possibility that ecological functions of the microbiome may vary substantially over hourly timescales, notably between day and night. Further studies are needed to compare temporal change in the coral microbiome with that due to other factors, such as spatial distance within and among colonies.

Non-targeted metabolomics of intestinal flora in seborrheic patients based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) techniques.

To explore the role of intestinal flora in seborrhea, non-targeted metabolomics analysis was carried out. Fecal samples were collected from 5 seborrheic patients and 5 healthy controls from October 2019 to April 2020. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) was used to detect metabolic fingerprinting in feces samples, and high-throughput sequencing and bioinformatic analysis of 16S rRNA for intestinal flora. The variable importance in projection (VIP) values of orthogonal partial least squares-discriminant analysis (OPLS-DA) and P values of univariate statistical analysis were used to determine the differential metabolites between the seborrhea group and the control group. The interaction between flora and metabolites was analyzed using several approaches. A total of 45 metabolites with significantly different intensities were found between the seborrhea group and the healthy control group. A positive correlation between flora and metabolites was found in 57 pairs and a negative correlation was found in 104 pairs. In addition, 11 metabolic pathways were significantly altered, including 4 amino acid metabolic pathways, 2 bile acid metabolic pathways, and 2 basic metabolic signaling pathways (ABC transporters pathway and mTOR signaling pathway). Central carbon metabolism in cancer, glutathione metabolism, protein digestion and absorption were also involved. The occurrence of seborrhea may be related to changes in intestinal flora and metabolic pathways. There is a close association between seborrhea and amino acid metabolic pathways or ABC transporters.

Selenium Enriched Peanut Protein Alleviates Alcohol-Induced Liver Damage in Mice by Modulating the Composition of the Gut Microbiota

Alcohol Use Disorder (AUD) is one of leading external causes of mortality. Selenium-enriched Peanut Protein (SePP) is a type of Se compound present in Se-enriched plants. Our previous studies showed that SePP possesses potential therapeutic properties and could alleviate alcohol-induced AML-12 cytotoxicity. It spurred us to determine the underlying mechanisms and roles of SePP on gut microbiota. Here, ICR mice were fed either standard diet or ethanol (30%, v/v, 10 mL/kg bw/day) intragastric administration for 8 weeks. The intervention groups were divided into different doses of SePP groups and Se compounds groups, like Selenomethionine (SeMet) group, sodium selenite group. The composition of the gut microbiota was investigated by analyzing 16S rRNA gene sequences. Body weight, lipid metabolism markers, serum insulin and oxidative stress were assessed. Treatment with SePP at a certain dosage (25 μg/kg bw/day in Se) and SeMet reversed diversity loss and community alterations in the gut microbiota of the AUD group, as evidenced by an increased abundance of Firmicutes and decreased abundances of Bacteroidetes and Verrucomicrobia in AUD mice. SePP suppressed the relative abundance of the Rikenellaceae_RC9 gut group and increased those of Lachnospiraceae and Ruminococcaceae, which are associated with lipid metabolism and Short-Chain Fatty Acids (SCFAs) production. The study suggested that SePP has the potential to be used as a supplement for alleviating alcohol-induced liver damage.

#82: Osteomyelitis with Panton-Valentine Leukocidin Producing Staphylococcus aureus Strains, Experience in a Tertiary Pediatric Hospital in Mexico City

Abstract Background S. aureus is the most common cause of osteomyelitis in children. Panton-Valentine leucocidin (PVL) is an exotoxin produced by certain S. aureus strains, which can be detected in both methicillin-sensitive and -resistant strains of staphylococci. Pediatric osteomyelitis by PVL producing S. aureus constitute a rare, but highly critical event. They are characterized by a rapid course of marked inflammation, worsening under conservative therapy, and a high rate of recurrence. No information is available on osteomyelitis and Panton-Valentine leukocidin producing S. aureus in Mexico. Objective The aim of this study was to determine the molecular characterization of S. aureus strains isolated in pediatric patients with osteomyelitis and their clinical features in a tertiary hospital in Mexico City. Methods We conducted a prospective study of children admitted for osteomyelitis, between December 2018 and November 2019, at Instituto Nacional de Pediatría. We obtained an informed consent in children under 12 years of age and an informed assent in children over 12. The confirmation of the S. aureus isolates was performed by amplification and analysis of 16S rRNA and nuc genes. The mecA and pvl genes were detected by PCR, the clinical features were obtained at the admission. Results Fifty patients were included and 26 cases of osteomyelitis were diagnosed, 13 were due to staphylococcus aureus genus and 6 due to S. aureus; all of them were methicillin susceptible and two were PVL producers. Both patients had a severe initial presentation, with extensive local abscesses, and one required three surgical procedures and developed septic pulmonary embolism. The two patients received double antimicrobial treatment and required a long therapy interval. Conclusions Osteomyelitis with Panton-Valentine Leukocidin producing S. aureus seems to be more severe. In patients with severe osteomyelitis, it is essential to detect the PVL toxin because they require early surgical intervention and prolonged intravenous therapy. Our findings suggest that the severity of the osteomyelitis is linked with PVL production more than with methicillin resistance due to that all our isolates were methicillin susceptible.

Effect of two contrasting biochars on soil microbiota in the humid tropics of Peninsular Malaysia

Report on soil microbial community in tropical soil of humid tropics remained limited despite the current research interest in biochar-microbe study in various climatic regions. A field-trial spanning three consecutive crop cycles of Zea mays var. Masmadu was conducted in tropical Acrisols of Peninsular Malaysia. Palm kernel shell and rice husk biochars of different feedstock and pyrolysis conditions were used for amendment. Soil samples were collected during maize harvesting and were analyzed for physicochemical properties (pH, CEC, organic C, labile active C), microbial biomass (C, N), and seven C-cycle enzymes activity (total cellulase, endoglucanase, β-glucosidase, xylanase, invertase, phenol oxidase, peroxidase). Total soil genomic DNA was extracted and subjected to the analysis of bacterial 16S rRNA and fungal ITS gene abundance quantification. Microbial genetic profiling was fingerprinted by using DGGE. Significant increases of all measured soil physicochemical properties, microbial biomass C, microbial biomass N, and gene abundances were observed in all biochar amended soils. Significant changes of total cellulase, endoglucanase, phenol oxidase, and peroxidase were not detected. A significant shift in microbial genotypic and enzymatic functional diversity based on microbial C-cycle enzymes was not detected. Correlation data revealed significant linkages of soil microbial biomasses and gene abundances with all measured soil physicochemical properties. The biochar influences the microbial community by elevating microbial habitat potential to a more favorable state and increasing labile active carbon sources in the field trial.

Characterization and identification of Burkholderia glumae as the causal pathogen of bacterial panicle blight of rice (Oryza sativa L.) in Malaysian rice granaries

Bacterial panicle blight (BPB) like symptoms in rice plants were first detected in Sungai Ache, Penang, Malaysia in December 2017. The symptoms observed were straw-coloured panicles, discoloured florets with darker basal portion of the glumes. The panicles remained upright due to partially or aborted grain filling. The causal pathogen was confirmed as B. glumae based on phenotypic characterization, molecular identification, and phylogenetic analysis of 16S rRNA and gyrB genes. Koch’s postulates were fulfilled and pathogenic variations among the isolates were observed. This study is the first report of the occurrence of BPB caused by B. glumae in Malaysia.

Molecular Characterization and Antibiogram Profiling of Multidrug Resistant Staphylococcus haemolyticus Isolated from Patients with Urinary Tract Infection in Bangladesh

The emergence of antibiotic-resistant bacteria in human is a potential global public health concern. Profiling of antibiotic-resistant bacteria with their antimicrobial susceptibility patterns from Urinary Tract Infections (UTIs) is crucial to guide antibiotic therapy. Herein we report a detailed bacteriological and molecular analysis of Staphylococcus haemolyticus and their antibiogram typing from UTIs. A total of 100 human urine samples of patients with UTIs were collected between January and December 2019 and were subjected to the conventional characterization of bacteria using the standard protocol. Molecular characterization was performed via sequencing followed by phylogenetic analysis. All bacterial strains were examined against thirteen commonly used antibiotics for susceptibility using the Kirby-Bauer disk diffusion method. The overall prevalence of S. haemolyticus in UTI was 26% with female patients having a higher prevalence of UTI (21 out of 26 or 80.76%) than male patients (5 out of 26 or 19.24%). The isolated S. haemolyticus showed 100%, 100%, 88.46%%, 76.93%, 73.08% and 65.39% resistant to penicillin, ampicillin, amoxicillin, erythromycin, ciprofloxacin and tetracycline, respectively. Importantly, S. haemolyticus demonstrated the highest sensitivity to vancomycin (100%), followed by azithromycin (80.76%), amikacin (84.61%), gentamycin (69.23%), levofloxacin (73.08%), ceftriaxone (80.76%) and doxycycline (61.54%). Overall, six variations were noted in S. haemolyticus in which most (5/6) modifications were substitutions and one (1/6) was deletion. These findings imply that mutations in the 16S rRNA gene sequence are the dominant source for species identification and variation in the drug sensitivity pattern against the S. haemolyticus. Phylogenetic analysis of the resultant 16S rRNA indicated that the isolated S. haemolyticus in this study belonged to genus Staphylococcus, but was different from the rest of the available S. haemolyticus isolates in other countries. Multidrug-resistant pathogenic S. hemolyticus is commonly found in urine samples of UTI in human in Bangladesh, which warrants a one-health approach for controlling this emerging ailment.

Occurrence and Toxicogenetic Profiling of Clostridium perfringens in Buffalo and Cattle: An Update from Pakistan.

Clostridium perfringens is a Gram-positive bacterium that possess seven toxinotypes (A, B, C, D, E, F, and G) that are responsible for the production of six major toxins, i.e., α, β, ε, ι, CPE, and NetB. The aim of this study is to find out the occurrence of toxinotypes in buffalo and cattle of Punjab province in Pakistan and their corresponding toxin-encoding genes from the isolated toxinotypes. To accomplish this aim, six districts in Punjab province were selected (i.e., Lahore, Sahiwal, Cheecha Watni, Bhakkar, Dera Ghazi Khan, and Bahawalpur) and a total of 240 buffalo and 240 cattle were selected for the collection of samples. From isolation and molecular analysis (16S rRNA), it was observed that out of seven toxinotypes (A–G), two toxinotypes (A and D) were found at most, whereas other toxinotypes, i.e., B, C, E, F, and G, were not found. The most frequently occurring toxinotype was type A (buffalo: 149/240; cattle: 157/240) whereas type D (buffalo: 8/240 cattle: 7/240) was found to occur the least. Genes encoding toxinotypes A and D were cpa and etx, respectively, whereas genes encoding other toxinotypes were not observed. The occurrence of isolated toxinotypes was studied using response surface methodology, which suggested a considerable occurrence of the isolated toxinotypes (A and D) in both buffalo and cattle. Association between type A and type D was found to be significant among the isolated toxinotypes in both buffalo and cattle (p ≤ 0.05). Correlation was also found to be positive and significant between type A and type D. C. perfringens exhibits a range of toxinotypes that can be diagnosed via genotyping, which is more reliable than classical toxinotyping.

English

Canine Ehrlichiosis is caused by Ehrlichia canis, an obligate intracellular bacterium. In Egypt, the epidemiology data about Ehrlichia canis is very limited and the molecular characterization of the organism has not been identified. Therefore, the objectives of this study were to study the prevalence of E. canis among 400 examined Egyptian dogs based on PCR assay and subsequently analyze the results by the logistic regression model. Furthermore, the molecular characterization of the Egyptian strain of E. canis was investigated. Generally, the prevalence of E. canis among dogs was 9.7%. The age, veterinary care, tick infestation, and antiparasitic treatment have a significant effect on the prevalence of E. canis in dogs as the prevalence rate was higher in older dogs (11.8%) and heavily infested dogs with ticks (10.3%) but lower in dogs received veterinary care (7.5%) and antiparasitic treatment (4.2%). In contrast, the sex, breed, and health status of dogs showed no significant role in the infection with E. canis. Sequence analysis of 16S rRNA for the Egyptian strain of E. canis revealed 100% identity with that of the American strain of E. canis and represented in one clade as obtained with a phylogenetic tree. The present study is the first study on molecular characterization of the Egyptian strain of E. canis, according to our knowledge

Microenvironmental Conditions Drive the Differential Cyanobacterial Community Composition of Biocrusts from the Sahara Desert

The Sahara Desert is characterized by extreme environmental conditions, which are a unique challenge for life. Cyanobacteria are key players in the colonization of bare soils and form assemblages with other microorganisms in the top millimetres, establishing biological soil crusts (biocrusts) that cover most soil surfaces in deserts, which have important roles in the functioning of drylands. However, knowledge of biocrusts from these extreme environments is limited. Therefore, to study cyanobacterial community composition in biocrusts from the Sahara Desert, we utilized a combination of methodologies in which taxonomic assignation, for next-generation sequencing of soil samples, was based on phylogenetic analysis (16S rRNA gene) in parallel with morphological identification of cyanobacteria in natural samples and isolates from certain locations. Two close locations that differed in microenvironmental conditions were analysed. One was a dry salt lake (a “chott”), and the other was an extension of sandy, slightly saline soil. Differences in cyanobacterial composition between the sites were found, with a clear dominance of Microcoleus spp. in the less saline site, while the chott presented a high abundance of heterocystous cyanobacteria as well as the filamentous non-heterocystous Pseudophormidium sp. and the unicellular cf. Acaryochloris. The cyanobacteria found in our study area, such as Microcoleus steenstrupii, Microcoleus vaginatus, Scytonema hyalinum, Tolypothrix distorta, and Calothrix sp., are also widely distributed in other geographic locations around the world, where the conditions are less severe. Our results, therefore, indicated that some cyanobacteria can cope with polyextreme conditions, as confirmed by bioassays, and can be considered extremotolerant, being able to live in a wide range of conditions.

Dietary supplemental xylooligosaccharide modulates nutrient digestibility, intestinal morphology, and gut microbiota in laying hens.

This study was conducted to evaluate the prebiotic effects of dietary xylooligosaccharide (XOS) supplementation on performance, nutrient digestibility, intestinal morphology, and gut microbiota in laying hens. In a 12-wk experiment, a total of 288 Hy-Line Brown layers at 50 wk of age were randomly assigned into 3 dietary treatments supplemented with XOS at 0, 200 or 400 mg/kg. Each treatment had 8 replicates with 12 birds each. Hens fed XOS diets showed a lower feed-to-egg ratio during wk 7 to 12 and a higher egg yolk color value in wk 12 compared with those fed the control diet (P < 0.05). Dietary XOS supplementation improved the apparent total tract digestibility of gross energy and nitrogen at the end of the 12th wk (P < 0.05). In addition, a higher villus height-to-crypt depth ratio of the ileum was observed in XOS-added groups (P < 0.05). The high throughput sequencing analysis of bacterial 16S rRNA revealed that dietary XOS supplementation at 200 mg/kg altered cecal microbiota. Alpha diversity analysis illustrated a higher cecal bacterial richness in birds fed with XOS at 200 mg/kg. The composition of cecal microbiota modulated by the XOS addition was characterized by an increased abundance of Firmicutes along with a reduced abundance of Bacteroidetes. At the genus level, dietary XOS supplementation triggered decreases in Bacteroides and Campylobacter concurrent with increases in Lactobacillus and several short chain fatty acid producers including Desulfovibrio, Faecalitalea, Faecalicoccus, and 5 genera of family Lachnospiraceae. Collectively, dietary XOS addition improved the feed conversion ratio by modulating nutrient digestibility and ileal morphology in laying hens, which could be attributed to the enhancement of bacterial diversity and alteration of microbial composition.

Influence of thermal assistance on the biodegradation of organics during food waste bio-drying: Microbial stimulation and energy assessment

Recently, bio-drying was highlighted in the drying pretreatment of high-moisture organic wastes for their energy recovery. In this study, to investigate the influences of thermal assistance on microbial stimulation and energy utilization in organic degradation, thermally assisted bio-drying (TB) was conducted on food waste (FW) and was compared with conventional bio-drying (CB) and thermal drying (TD). As expected, more water was removed in TB, which exhibited no lag phenomenon and intensified microbial activity. Corresponding with the stimulated enzyme activity, more readily degradable carbohydrates, lipids and lignocellulose were decomposed in TB than those in CB, and lipid degradation generated a significant proportion of the total bio-heat generated (43.13%–45.83%). Furthermore, according to the microbial analysis (qPCR and 16S rRNA gene sequencing), Bacillus was found to be the dominant genus involved in the degradation of organics during TB and CB. In the initial phase, rather than Weissella, as in CB, Ureibacillus was notable in TB for the degradation of readily degradable substrates. In the late phase, Pseudoxanthomonas and Saccharomonospora were enriched for degrading lignocellulose. In addition, heat balance and life-cycle energy assessment demonstrated that a small amount of thermal heat (11.96%) upgraded bio-drying with high energy efficiency. Compared with the CB and TD processes, the TB trial consumed less thermal energy (0.58 MJ/kg H2O) and achieved a higher energy output/input ratio (3.64). This research suggests that thermal assistance is a promising approach to enhancing FW bio-drying, which exhibits efficient drying performance and great potential for energy recovery.

Short-Term Oral Administration of Mesoporous Silica Nanoparticles Potentially Induced Colon Inflammation in Rats Through Alteration of Gut Microbiota.

PurposeMesoporous silica (MSNs) have attracted considerable attention for its application in the field of drug delivery and biomedicine due to its high surface area, large pore volume, and low toxicity. Recently, numerous studies revealed that gut microbiota is of critical relevance to host health. However, the toxicological studies of MSNs were mainly based on the degradation, biodistribution, and excretion in mammalian after oral administration for now. Here in this study, we explored the impacts of oral administration of three kinds of MSNs on gut microbiota in rats to assess its potential toxicity.MethodsForty rats were divided into four groups: control group; Mobil Composition of Matter No. 41 type mesoporous silica (MCM-41) group; Santa Barbara Amorphous-15 type mesoporous silica (SBA-15) group, and biodegradable dendritic center-radial mesoporous silica nanoparticle (DMSN) group. Fecal samples were collected 3 days and 7 days after the intake of MSNs and analyzed with high throughput sequencing. Gastric tissues in rats were obtained after dissection for the histological study.ResultsThree different MSNs (MCM-41, SBA-15, and DMSN) were successfully prepared in this study. The pore size of three MSNs was calculated similarly as (3.54 ± 0.15) nm, (3.48 ± 0.21) nm, and (3.45 ± 0.17) nm according to the BET & BJH model, respectively, while the particle size of MCM-41, SBA-15 and DMSN was around 209.2 nm, 1349.56 nm, and 244.4 nm, respectively. In the gene analysis of 16S rRNA, no significant changes in the diversity and richness were found between groups, while Verrucomicrobia decreased and Candidatus Saccharibacteria increased in MCM-41 treated groups. Meanwhile, no inflammatory and erosion symptoms were observed in the morphological analysis of the colons, except the MCM-41 treated group.ConclusionThree different MSNs, MCM-41, SBA-15, and DMSN were successfully prepared, and this study firstly suggested the impact of MSNs on the gut microbiota, and further revealing the potential pro-inflammatory effects of oral administration of MCM-41 was possibly through the changing of gut microbiota.