Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 11 de 11
Filter
1.
Environ Microbiome ; 17(1): 60, 2022 Dec 21.
Article in English | MEDLINE | ID: mdl-36544228

ABSTRACT

Lake Hillier is a hypersaline lake known for its distinctive bright pink color. The cause of this phenomenon in other hypersaline sites has been attributed to halophiles, Dunaliella, and Salinibacter, however, a systematic analysis of the microbial communities, their functional features, and the prevalence of pigment-producing-metabolisms has not been previously studied. Through metagenomic sequencing and culture-based approaches, our results evidence that Lake Hillier is composed of a diverse set of microorganisms including archaea, bacteria, algae, and viruses. Our data indicate that the microbiome in Lake Hillier is composed of multiple pigment-producer microbes, including Dunaliella, Salinibacter, Halobacillus, Psychroflexus, Halorubrum, many of which are cataloged as polyextremophiles. Additionally, we estimated the diversity of metabolic pathways in the lake and determined that many of these are related to pigment production. We reconstructed complete or partial genomes for 21 discrete bacteria (N = 14) and archaea (N = 7), only 2 of which could be taxonomically annotated to previously observed species. Our findings provide the first metagenomic study to decipher the source of the pink color of Australia's Lake Hillier. The study of this pink hypersaline environment is evidence of a microbial consortium of pigment producers, a repertoire of polyextremophiles, a core microbiome and potentially novel species.

2.
JGH Open ; 5(9): 1099-1102, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34584982

ABSTRACT

Fecal microbiota transplantation (FMT) is effective for induction of remission in ulcerative colitis (UC). Diet has potential to augment the efficacy and durability of FMT by encouraging engraftment of transplanted microorganisms. A trial of FMT combined with a defined diet was undertaken as salvage therapy for a 71-year-old woman with active steroid-refractory extensive UC. A multidimensional sulfide-reducing diet (4-SURE diet) was commenced followed by single-donor FMT administered by colonoscopy and then enemas over 7 days. Dietary adherence, clinical evaluation, and stool samples for metagenomic profiling were undertaken at weeks 0, 4, 8, and 24. Colonoscopy was performed 8 weeks post-FMT. Shotgun metagenomic profiling of the donor fecal suspension was also performed. A rapid clinical response to FMT and 4-SURE diet was observed with normalization of stool frequency (≤2 motions/day) and resolution of rectal bleeding within 2 weeks. Dietary adherence was excellent. Colonoscopy at week 8 revealed no evidence of active colitis (Mayo endoscopic sub-score 0) with histology showing no evidence of acute or chronic lamina propria inflammatory cell infiltrate. Sustained clinical and endoscopic remission out to 24 weeks was observed. Metagenomic sequencing confirmed sustained engraftment of beneficial donor microbiota with increased alpha-diversity and capacity for short-chain fatty acid production, including Faecalibacterium prauznitzii and Eubacterium hallii. This case report supports the rationale of prescribed diet therapy to support engraftment of donor microbiota following FMT for UC. Further large trials with a diet-arm control group are needed to evaluate FMT augmented by a defined diet in UC.

3.
J Biomol Tech ; 28(1): 31-39, 2017 04.
Article in English | MEDLINE | ID: mdl-28337070

ABSTRACT

The Extreme Microbiome Project (XMP) is a project launched by the Association of Biomolecular Resource Facilities Metagenomics Research Group (ABRF MGRG) that focuses on whole genome shotgun sequencing of extreme and unique environments using a wide variety of biomolecular techniques. The goals are multifaceted, including development and refinement of new techniques for the following: 1) the detection and characterization of novel microbes, 2) the evaluation of nucleic acid techniques for extremophilic samples, and 3) the identification and implementation of the appropriate bioinformatics pipelines. Here, we highlight the different ongoing projects that we have been working on, as well as details on the various methods we use to characterize the microbiome and metagenome of these complex samples. In particular, we present data of a novel multienzyme extraction protocol that we developed, called Polyzyme or MetaPolyZyme. Presently, the XMP is characterizing sample sites around the world with the intent of discovering new species, genes, and gene clusters. Once a project site is complete, the resulting data will be publically available. Sites include Lake Hillier in Western Australia, the "Door to Hell" crater in Turkmenistan, deep ocean brine lakes of the Gulf of Mexico, deep ocean sediments from Greenland, permafrost tunnels in Alaska, ancient microbial biofilms from Antarctica, Blue Lagoon Iceland, Ethiopian toxic hot springs, and the acidic hypersaline ponds in Western Australia.


Subject(s)
Environmental Microbiology , Microbiota/genetics , DNA, Bacterial/genetics , DNA, Bacterial/isolation & purification , Extreme Environments , Metagenome , Molecular Typing/standards , RNA, Bacterial/genetics , RNA, Bacterial/isolation & purification , Reference Standards , Sequence Analysis, DNA/standards
4.
J Wildl Dis ; 53(2): 248-257, 2017 04.
Article in English | MEDLINE | ID: mdl-28118558

ABSTRACT

Hereditary disorders and genetic predispositions to disease are rarely reported in captive and free-ranging wildlife, and none have been definitively identified and characterized in elephants. A wild-caught, 41-yr-old male Asian elephant ( Elephas maximus ) without an apparent increased bleeding tendency was consistently found to have prolonged prothrombin times (PTs, mean=55±35 s) compared to 17 other elephants (PT=10±2 s). This elephant's partial thromboplastin times (PTT) fell within the normal range of the other elephants (12-30 s). A prolonged PT in the presence of a normal PTT suggests disruption of the extrinsic pathway via deficiency of coagulation Factor VII (FVII). This elephant's plasma FVII activity was very low (2%) compared to that of 15 other elephants (57-80%), but other coagulation factors' activities did not differ from the control elephants. Sequencing of genomic DNA from ethylenediaminetetraacetic acid blood revealed a single homozygous point mutation (c.202A>G) in the F7 gene of the FVII deficient elephant that was not present in unrelated elephants. This mutation causes an amino acid substitution (p.Arg68Gly) that is predicted to be deleterious. Two living offspring of the affected elephant were heterozygous for the mutation and had normal plasma FVII activities and coagulation profiles. Tissue from a third offspring, a deceased calf, was utilized to show that it was also a heterozygote. A DNA test has been developed to enable the screening of additional elephants for this mutation. Consistent with FVII deficiency investigations in other species, the condition did not cause a serious bleeding tendency in this individual elephant.


Subject(s)
Elephants/genetics , Factor VII Deficiency/veterinary , Mutation, Missense , Animals , Animals, Wild , Male , Mutation
5.
NPJ Microgravity ; 2: 16035, 2016.
Article in English | MEDLINE | ID: mdl-28725742

ABSTRACT

Rapid DNA sequencing and analysis has been a long-sought goal in remote research and point-of-care medicine. In microgravity, DNA sequencing can facilitate novel astrobiological research and close monitoring of crew health, but spaceflight places stringent restrictions on the mass and volume of instruments, crew operation time, and instrument functionality. The recent emergence of portable, nanopore-based tools with streamlined sample preparation protocols finally enables DNA sequencing on missions in microgravity. As a first step toward sequencing in space and aboard the International Space Station (ISS), we tested the Oxford Nanopore Technologies MinION during a parabolic flight to understand the effects of variable gravity on the instrument and data. In a successful proof-of-principle experiment, we found that the instrument generated DNA reads over the course of the flight, including the first ever sequenced in microgravity, and additional reads measured after the flight concluded its parabolas. Here we detail modifications to the sample-loading procedures to facilitate nanopore sequencing aboard the ISS and in other microgravity environments. We also evaluate existing analysis methods and outline two new approaches, the first based on a wave-fingerprint method and the second on entropy signal mapping. Computationally light analysis methods offer the potential for in situ species identification, but are limited by the error profiles (stays, skips, and mismatches) of older nanopore data. Higher accuracies attainable with modified sample processing methods and the latest version of flow cells will further enable the use of nanopore sequencers for diagnostics and research in space.

7.
Appl Environ Microbiol ; 76(21): 7161-70, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20851978

ABSTRACT

Functional attributes of microbial communities are difficult to study, and most current techniques rely on DNA- and rRNA-based profiling of taxa and genes, including microarrays containing sequences of known microorganisms. To quantify gene expression in environmental samples in a culture-independent manner, we constructed an environmental functional gene microarray (E-FGA) consisting of 13,056 mRNA-enriched anonymous microbial clones from diverse microbial communities to profile microbial gene transcripts. A new normalization method using internal spot standards was devised to overcome spotting and hybridization bias, enabling direct comparisons of microarrays. To evaluate potential applications of this metatranscriptomic approach for studying microbes in environmental samples, we tested the E-FGA by profiling the microbial activity of agricultural soils with a low or high flux of N2O. A total of 109 genes displayed expression that differed significantly between soils with low and high N2O emissions. We conclude that mRNA-based approaches such as the one presented here may complement existing techniques for assessing functional attributes of microbial communities.


Subject(s)
Oligonucleotide Array Sequence Analysis/methods , Soil Microbiology , Biota , DNA, Bacterial/analysis , DNA, Bacterial/genetics , DNA, Complementary/genetics , Genes, Bacterial/genetics , Nitrogen Fixation/genetics , RNA, Bacterial/analysis , RNA, Bacterial/genetics , Soil/analysis
8.
J Microbiol Methods ; 75(2): 172-6, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18582973

ABSTRACT

The advent of metagenomics has revealed that our planet harbors millions of previously undiscovered microbial species. However, functional insights into the activities of microbial communities cannot easily be obtained using metagenomics. Using transcriptional analyses to study microbial gene functions is currently problematic due to difficulties working with unstable microbial mRNA as a small fraction of total cellular RNA. Current techniques can be expensive and time consuming, and still result in significant levels of rRNA contamination. We have adapted techniques to rapidly isolate high high-quality RNA from environmental samples and developed a simple method for specific isolation of mRNA by size separation. This new technique was evaluated by constructing cDNA libraries directly from uncultured environmental microbial communities, including agricultural soil samples, aquatic flocculants, organic composts, mammalian oral and faecal samples, and wastewater sludge. The sequencing of a fraction of these cDNA clones revealed a high degree of novelty, demonstrating the potential of this approach to capture a large number of unique transcripts directly from the environment. To our knowledge, this is the first study that uses gel electrophoresis to isolate mRNA from microbial communities. We conclude that this method could be used to provide insights into the microbial 'metatranscriptome' of entire microbial communities. Coupled with high-throughput sequencing or the construction of cDNA microarrays, this approach will provide a useful tool to study the transcriptional activities of microorganisms, including those of entire microbial communities and of non-culturable microorganisms.


Subject(s)
Environmental Microbiology , Gene Expression Profiling , RNA, Messenger , Animals , Cattle , Cloning, Molecular , Ecosystem , Feces/microbiology , Fresh Water/microbiology , Gene Library , Humans , Mouth/microbiology , RNA, Messenger/analysis , RNA, Messenger/genetics , RNA, Messenger/isolation & purification , RNA, Ribosomal, 16S/genetics , Rumen/microbiology , Sequence Analysis, DNA , Soil Microbiology
9.
Plant Physiol ; 139(2): 949-59, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16183832

ABSTRACT

To identify transcription factors (TFs) involved in jasmonate (JA) signaling and plant defense, we screened 1,534 Arabidopsis (Arabidopsis thaliana) TFs by real-time quantitative reverse transcription-PCR for their altered transcript at 6 h following either methyl JA treatment or inoculation with the incompatible pathogen Alternaria brassicicola. We identified 134 TFs that showed a significant change in expression, including many APETALA2/ethylene response factor (AP2/ERF), MYB, WRKY, and NAC TF genes with unknown functions. Twenty TF genes were induced by both the pathogen and methyl JA and these included 10 members of the AP2/ERF TF family, primarily from the B1a and B3 subclusters. Functional analysis of the B1a TF AtERF4 revealed that AtERF4 acts as a novel negative regulator of JA-responsive defense gene expression and resistance to the necrotrophic fungal pathogen Fusarium oxysporum and antagonizes JA inhibition of root elongation. In contrast, functional analysis of the B3 TF AtERF2 showed that AtERF2 is a positive regulator of JA-responsive defense genes and resistance to F. oxysporum and enhances JA inhibition of root elongation. Our results suggest that plants coordinately express multiple repressor- and activator-type AP2/ERFs during pathogen challenge to modulate defense gene expression and disease resistance.


Subject(s)
Arabidopsis/genetics , Arabidopsis/metabolism , Cyclopentanes/metabolism , Ethylenes/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Gene Expression , Genes, Plant , Genome, Plant , Oxylipins , Phylogeny , Plant Diseases/genetics , Repressor Proteins/genetics , Repressor Proteins/metabolism , Signal Transduction , Trans-Activators/genetics , Trans-Activators/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism
10.
Pain ; 111(3): 313-322, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15363875

ABSTRACT

We investigated adverse events (AEs) associated with perioperative tenoxicam in a double-blind, prospective, randomised study. Patients undergoing surgery, screened for contraindications to non-steroidal anti-inflammatory drug, received tenoxicam (n=750) on 2843 days or placebo (n=251) on 988 days, in courses of 1-12 days. There was no increase in the overall incidence of side effects with tenoxicam (33 vs 38% with placebo: P=0.15), or in major side effects (3.9 vs 2.0% with placebo: P=0.11). Of major side effects possibly or probably related to tenoxicam (2.1 vs 1.2% with placebo: P=0.26), all but one involved post-operative surgical site bleeding. However, in the subgroup of patients undergoing otorhinolaryngology surgery, surgical site bleeding occurred in 18 of 171 (10.5%) patients on tenoxicam and one of 57 (1.8%) on placebo (P=0.026); of these, nine in the tenoxicam group and 0 in the placebo were classified as major (P=0.07). One patient on tenoxicam experienced endoscopically proven duodenal ulceration with malaena. In conclusion, perioperative tenoxicam is well tolerated in comparison with placebo and the incidence of drug-related major AEs (other than post-operative bleeding) is no greater than 1 in 150 in low risk patients, but in patients undergoing otorhinolaryngological surgery there may be an increased risk of post-operative bleeding.


Subject(s)
Perioperative Care/methods , Piroxicam/analogs & derivatives , Piroxicam/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Confidence Intervals , Double-Blind Method , Female , Gastrointestinal Diseases/chemically induced , Humans , Male , Middle Aged , Perioperative Care/statistics & numerical data , Piroxicam/therapeutic use , Prospective Studies
11.
Plant Physiol ; 132(2): 1020-32, 2003 Jun.
Article in English | MEDLINE | ID: mdl-12805630

ABSTRACT

The PDF1.2 gene of Arabidopsis encoding a plant defensin is commonly used as a marker for characterization of the jasmonate-dependent defense responses. Here, using PDF1.2 promoter-deletion lines linked to the beta-glucoronidase-reporter gene, we examined putative promoter elements associated with jasmonate-responsive expression of this gene. Using stably transformed plants, we first characterized the extended promoter region that positively regulates basal expression from the PDF1.2 promoter. Second, using promoter deletion constructs including one from which the GCC-box region was deleted, we observed a substantially lower response to jasmonate than lines carrying this motif. In addition, point mutations introduced into the core GCC-box sequence substantially reduced jasmonate responsiveness, whereas addition of a 20-nucleotide-long promoter element carrying the core GCC-box and flanking nucleotides provided jasmonate responsiveness to a 35S minimal promoter. Taken together, these results indicated that the GCC-box plays a key role in conferring jasmonate responsiveness to the PDF1.2 promoter. However, deletion or specific mutations introduced into the core GCC-box did not completely abolish the jasmonate responsiveness of the promoter, suggesting that the other promoter elements lying downstream from the GCC-box region may also contribute to jasmonate responsiveness. In other experiments, we identified a jasmonate- and pathogen-responsive ethylene response factor transcription factor, AtERF2, which when overexpressed in transgenic Arabidopsis plants activated transcription from the PDF1.2, Thi2.1, and PR4 (basic chitinase) genes, all of which contain a GCC-box sequence in their promoters. Our results suggest that in addition to their roles in regulating ethylene-mediated gene expression, ethylene response factors also appear to play important roles in regulating jasmonate-responsive gene expression, possibly via interaction with the GCC-box.


Subject(s)
Arabidopsis/genetics , Cyclopentanes/pharmacology , Defensins , Gene Expression Regulation, Plant/genetics , Plant Proteins/genetics , Arabidopsis/drug effects , Arabidopsis Proteins/genetics , Base Sequence , Blotting, Northern , DNA Primers , Gene Expression Regulation, Plant/drug effects , Kinetics , Oxylipins , Plant Growth Regulators/pharmacology , Plants, Genetically Modified/drug effects , Plants, Genetically Modified/genetics , Polymerase Chain Reaction , Promoter Regions, Genetic/drug effects , Reverse Transcriptase Polymerase Chain Reaction , Transcription, Genetic/drug effects
SELECTION OF CITATIONS
SEARCH DETAIL
...