AIMS: In this report, we characterized the probiotic potential of Lactobacillus mucosae LM1, focusing on its in vitro mucin‐adhesion abilities. METHODS AND RESULTS: Screening assays were used to ...evaluate LM1. Previous studies on Lact. mucosae species have been performed, but few have examined the ability of this species to adhere to and colonize the intestinal mucosa. Thus, adhesion, aggregation and pathogen inhibition assays of LM1 along with microbial adhesion to solvents (MATS) assay were carried out in comparison with another putative probiotic, Lactobacillus johnsonii PF01, and the commercial strain, Lactobacillus rhamnosus GG. Based on MATS assay, the cell surfaces of the lactobacilli strains were found to be hydrophobic and highly electron‐donating, but the average hydropathy (GRAVY) index of predicted surface‐exposed proteins in the LM1 genome indicated that most were hydrophilic. LM1 showed the highest adhesion, aggregation and hydrophobicity among the strains tested and significantly inhibited the adhesion of Escherichia coli K88 and Salmonella enterica serovar Typhimurium KCCM 40253. Correlations among adhesion, aggregation and hydrophobicity, as well as between coaggregation and displacement of E. coli, were observed. CONCLUSIONS: Increased adhesion may not always correlate with increased pathogen inhibition due to various strain‐specific mechanisms. Nevertheless, LM1 has promising probiotic properties that can be explored further using a genomics approach. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data on adhesion of LM1 strain showed a significant correlation between adhesion, hydrophobicity of cell surface and autoaggregation. This study gives basic knowledge for the elucidation of the adhesion mechanism of Lactobacillus sp. and prediction of its adherence in specific host models.
Mass extinctions occur frequently in natural history. While studies of animals that became extinct can be informative, it is the survivors that provide clues for mechanisms of adaptation when ...conditions are adverse. Here, we describe a survival pathway used by many species as a means for providing adequate fuel and water, while also providing protection from a decrease in oxygen availability. Fructose, whether supplied in the diet (primarily fruits and honey), or endogenously (via activation of the polyol pathway), preferentially shifts the organism towards the storing of fuel (fat, glycogen) that can be used to provide energy and water at a later date. Fructose causes sodium retention and raises blood pressure and likely helped survival in the setting of dehydration or salt deprivation. By shifting energy production from the mitochondria to glycolysis, fructose reduced oxygen demands to aid survival in situations where oxygen availability is low. The actions of fructose are driven in part by vasopressin and the generation of uric acid. Twice in history, mutations occurred during periods of mass extinction that enhanced the activity of fructose to generate fat, with the first being a mutation in vitamin C metabolism during the Cretaceous–Paleogene extinction (65 million years ago) and the second being a mutation in uricase that occurred during the Middle Miocene disruption (12–14 million years ago). Today, the excessive intake of fructose due to the availability of refined sugar and high‐fructose corn syrup is driving ‘burden of life style’ diseases, including obesity, diabetes and high blood pressure.
Content List ‐ This is an article from the symposium: “Bioinspirational medicine”.
Summary
The use of lactobacilli as probiotics in swine has been gaining attention due to their ability to improve growth performance and carcass quality, prevent gastrointestinal infection and most ...importantly, their ‘generally recognized as safe’ status. Previous studies support the potential of lactobacilli to regulate host immune systems, enhance gut metabolic capacities and maintain balance in the gut microbiota. Research on swine gut microbiota has revealed complex gut microbial community structure and showed the importance of Lactobacillus to the host's health. However, the species‐ and strain‐specific characteristics of lactobacilli that confer probiotic benefits are still not well understood. The diversity of probiotic traits in a complex gut ecosystem makes it challenging to infer the relationships between specific functions of Lactobacillus sp. and host health. In this review, we provide an overview of how lactobacilli play a pivotal role in the swine gut ecosystem and identify key characteristics that influence gut microbial community structure and the health of pigs. In addition, based on recent and ongoing meta‐omics and omics research on the gut microbiota of pigs, we suggest a workflow combining culture‐dependent and culture‐independent approaches for more effective selection of probiotic lactobacilli.
We previously reported on MetaBAT, an automated metagenome binning software tool to reconstruct single genomes from microbial communities for subsequent analyses of uncultivated microbial species. ...MetaBAT has become one of the most popular binning tools largely due to its computational efficiency and ease of use, especially in binning experiments with a large number of samples and a large assembly. MetaBAT requires users to choose parameters to fine-tune its sensitivity and specificity. If those parameters are not chosen properly, binning accuracy can suffer, especially on assemblies of poor quality. Here, we developed MetaBAT 2 to overcome this problem. MetaBAT 2 uses a new adaptive binning algorithm to eliminate manual parameter tuning. We also performed extensive software engineering optimization to increase both computational and memory efficiency. Comparing MetaBAT 2 to alternative software tools on over 100 real world metagenome assemblies shows superior accuracy and computing speed. Binning a typical metagenome assembly takes only a few minutes on a single commodity workstation. We therefore recommend the community adopts MetaBAT 2 for their metagenome binning experiments. MetaBAT 2 is open source software and available at https://bitbucket.org/berkeleylab/metabat.
Grouping large genomic fragments assembled from shotgun metagenomic sequences to deconvolute complex microbial communities, or metagenome binning, enables the study of individual organisms and their ...interactions. Because of the complex nature of these communities, existing metagenome binning methods often miss a large number of microbial species. In addition, most of the tools are not scalable to large datasets. Here we introduce automated software called MetaBAT that integrates empirical probabilistic distances of genome abundance and tetranucleotide frequency for accurate metagenome binning. MetaBAT outperforms alternative methods in accuracy and computational efficiency on both synthetic and real metagenome datasets. It automatically forms hundreds of high quality genome bins on a very large assembly consisting millions of contigs in a matter of hours on a single node. MetaBAT is open source software and available at https://bitbucket.org/berkeleylab/metabat.
•The effect of the ferrite volume fraction on corrosion characteristics was investigated.•The sites of meta-stable pit were generated at lower PREN phase.•The γ2 and Cr2N seemed to serve as a path ...for the corrosive environment.•There is some discrepancy between the measured values(Epit) and estimated values(PREN).
Three duplex stainless steel weldments were produced by changing the chromium element to study the correlation between the pitting corrosion characteristics and the component ratio of the dual phase. The pit morphologies showed that metastable pits were generated at a lower pitting resistance equivalent number (PREN) phase. The secondary austenite phases seemed to serve as a path for the corrosive environment regardless of the ferrite number (FN). There is some discrepancy between the measured values (pitting potential (Ep) through polarization test) and expected values (sequence ranked by PREN of weaker phase) in 1moll−1 NaCl solution at 60°C.
We evaluated the combined effects of vacuumed hydrogen peroxide vapour (VHPV) and vacuum‐sealed dry heat (vacuum heat, VH) to inactivate food‐borne pathogens (Salmonella Typhimurium, Escherichia coli ...O157:H7 and Listeria monocytogenes) on alfalfa seeds. Alfalfa seeds inoculated with food‐borne pathogens were sequentially treated initially with 1·0 ml of 0 or 30% VHPV for 1 min and later with dry heat (DH) or VH for 2 h, and the rate of seed germination was evaluated. The combination treatment decreased the populations of three food‐borne pathogens below the limit of detection (1·0 log CFU per gram) on alfalfa seeds without decreasing germinability. The sequential treatment using VHPV and VH greatly reduced the total treatment time needed to inactivate pathogens on alfalfa seeds by more than 5 log CFU per gram. These results demonstrate that a combination of VHPV and VH has potentially employed as a new method for pasteurization of alfalfa seeds without affecting their germinability.
Significance and Impact of the Study: Many researchers have focused their attention on developing techniques to reduce seed‐borne human pathogens. Dry heat is one of such treatments. However, dry heat treatment usually requires excessive time to reduce pathogens. In our study, a combination treatment using vacuumed hydrogen peroxide vapour and vacuumed dry heat greatly reduced the treatment time required to inactivate food‐borne pathogens inoculated on alfalfa seeds. This combination treatment can be used as an alternative pasteurization method in seed processing industries.
Although intracranial atherosclerotic disease is often encountered during endovascular treatment for acute vertebrobasilar occlusions, its clinical implication is not well-known. We aimed to evaluate ...whether intracranial atherosclerotic disease influences the clinical outcomes following endovascular treatment of acute vertebrobasilar occlusive stroke.
Fifty-one patients with acute vertebrobasilar occlusive stroke were included. The onset-to-groin puncture time was ≤12 hours, and aspiration- or stent-based thrombectomy was used as the primary treatment method. Following primary endovascular treatment, intracranial atherosclerotic disease (IAD group) was angiographically diagnosed when a fixed focal stenosis was observed at the occlusion site, whereas embolism (embolic group) was diagnosed if no stenosis was observed. Clinical and treatment variables were compared in both groups, and IAD was evaluated as a prognostic factor for clinical outcomes.
The baseline NIHSS score tended to be lower (14 versus 22,
= .097) in the IAD group (
= 19) than in the embolic group (
= 32). The procedural time was longer in the IAD group (96 versus 61 minutes,
= .002), despite similar rates of TICI 2b-3 (89.5% versus 87.5%,
= 1.000). The NIHSS score at 7 days was higher (21 versus 8,
= .060) and poor outcomes (mRS 4-6 at 3 months) were more frequent in the IAD group (73.7% versus 43.8%,
= .038). IAD (odds ratio, 5.469; 95% CI, 1.09-27.58;
= .040) was independently associated with poor outcomes.
An arterial occlusion related to IAD was associated with a longer procedural time and poorer clinical outcome. Further studies are warranted to elucidate the appropriate endovascular strategy.
Aims
To clone, characterize and compare the bile salt hydrolase (BSH) genes of Lactobacillus johnsonii PF01.
Methods and Results
The BSH genes were amplified by polymerase chain reaction (PCR) using ...specific oligonucleotide primers, and the products were inserted into the pET21b expression vector. Escherichia coli BLR (DE3) cells were transformed with pET21b vectors containing the BSH genes and induced using 0·1 mmol l−1 isopropylthiolgalactopyranoside. The overexpressed BSH enzymes were purified using a nickel–nitrilotriacetic acid (Ni2+‐NTA) agarose column and their activities characterized. BSH A hydrolysed tauro‐conjugated bile salts optimally at pH 5·0 and 55°C, whereas BSH C hydrolysed glyco‐conjugated bile salts optimally at pH 5·0 and 70°C. The enzymes had no preferential activities towards a specific cholyl moiety.
Conclusions
BSH enzymes vary in their substrate specificities and characteristics to broaden its activity. Despite the lack of conservation in their putative substrate‐binding sites, these remain functional through motif conservation.
Significance and Impact of the Study
This is to our knowledge the first report of isolation of BSH enzymes from a single strain, showing hydrolase activity towards either glyco‐conjugated or tauro‐conjugated bile salts. Future structural homology studies and site‐directed mutagenesis of sites associated with substrate specificity may elucidate specificities of BSH enzymes.
Microscopic interpretation of stained smears is one of the most operator-dependent and time-intensive activities in the clinical microbiology laboratory. Here, we investigated application of an ...automated image acquisition and convolutional neural network (CNN)-based approach for automated Gram stain classification. Using an automated microscopy platform, uncoverslipped slides were scanned with a 40× dry objective, generating images of sufficient resolution for interpretation. We collected 25,488 images from positive blood culture Gram stains prepared during routine clinical workup. These images were used to generate 100,213 crops containing Gram-positive cocci in clusters, Gram-positive cocci in chains/pairs, Gram-negative rods, or background (no cells). These categories were targeted for proof-of-concept development as they are associated with the majority of bloodstream infections. Our CNN model achieved a classification accuracy of 94.9% on a test set of image crops. Receiver operating characteristic (ROC) curve analysis indicated a robust ability to differentiate between categories with an area under the curve of >0.98 for each. After training and validation, we applied the classification algorithm to new images collected from 189 whole slides without human intervention. Sensitivity and specificity were 98.4% and 75.0% for Gram-positive cocci in chains and pairs, 93.2% and 97.2% for Gram-positive cocci in clusters, and 96.3% and 98.1% for Gram-negative rods. Taken together, our data support a proof of concept for a fully automated classification methodology for blood-culture Gram stains. Importantly, the algorithm was highly adept at identifying image crops with organisms and could be used to present prescreened, classified crops to technologists to accelerate smear review. This concept could potentially be extended to all Gram stain interpretive activities in the clinical laboratory.
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