Background:
A previous study has suggested that Bifidobacterium animalis DN‐173 010 shortens the colonic transit time in women.
Aim:
To confirm this effect and to determine whether modifications of ...the faecal bacterial mass and/or faecal secondary bile salts may be the explanation.
Methods:
A double‐blind, cross‐over study was performed. Thirty‐six healthy women were studied in four consecutive 10‐day periods. During periods 2 and 4, they ingested three 125 g cups per day of a fermented milk which was either a product containing B. animalis DN‐173 010 or a control without bifidobacteria. Periods 1 and 3 were run‐in and washout periods, respectively. The total and segmental colonic transit times were assessed using a pellet method. In 12 subjects, all stools were collected and analysed for pH, faecal weight, bacterial mass and bile acids.
Results:
The total and sigmoid transit times were significantly shorter during dosing with B. animalis compared to the control period. The other transit times, faecal weight, pH, bacterial mass and bile acids were not significantly affected.
Conclusions:
B. animalis DN‐173 010 shortens the colonic transit time in healthy women. This effect is not explained by modifications of the faecal bacterial mass or secondary bile acids.
Clostridium difficile is a leading cause of antibiotic-associated diarrhea. The mechanisms underlying C. difficile expansion after microbiota disturbance are just emerging. We assessed the gene ...expression profile of C. difficile within the intestine of gnotobiotic mice to identify genes regulated in response to either dietary or microbiota compositional changes. In the presence of the gut symbiont Bacteroides thetaiotaomicron, C. difficile induces a pathway that metabolizes the microbiota fermentation end-product succinate to butyrate. The low concentration of succinate present in the microbiota of conventional mice is transiently elevated upon antibiotic treatment or chemically induced intestinal motility disturbance, and C. difficile exploits this succinate spike to expand in the perturbed intestine. A C. difficile mutant compromised in succinate utilization is at a competitive disadvantage during these perturbations. Understanding the metabolic mechanisms involved in microbiota-C. difficile interactions may help to identify approaches for the treatment and prevention of C. difficile-associated diseases.
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•Biassociation with a gut symbiont induces a C. difficile succinate-utilization operon•Succinate accumulates in the gut upon antibiotic treatment or motility disturbance•Succinate utilization enables C. difficile expansion in the perturbed gut•A C. difficile mutant compromised in succinate utilization is colonization defective
Nutrient resource partitioning by gut microbes is typically efficient. Ferreyra et al. demonstrate that upon antibiotic treatment or motility disturbance, succinate, an interspecies metabolic intermediate, transiently spikes to high levels. C. difficile induces a succinate-to-butyrate conversion pathway to take advantage of the succinate spike and expand during these gut perturbations.
K.‐Y. Ryu, N. Fujiki, M. Kazantzis, J. C. Garza, D. M. Bouley, A. Stahl, X.‐Y. Lu, S. Nishino and R. R. Kopito (2010) Neuropathology and Applied Neurobiology36, 285–299 Loss of polyubiquitin gene Ubb ...leads to metabolic and sleep abnormalities in mice
Aims: Ubiquitin performs essential roles in a myriad of signalling pathways required for cellular function and survival. Recently, we reported that disruption of the stress‐inducible ubiquitin‐encoding gene Ubb reduces ubiquitin content in the hypothalamus and leads to adult‐onset obesity coupled with a loss of arcuate nucleus neurones and disrupted energy homeostasis in mice. Neuropeptides expressed in the hypothalamus control both metabolic and sleep behaviours. In order to demonstrate that the loss of Ubb results in broad hypothalamic abnormalities, we attempted to determine whether metabolic and sleep behaviours were altered in Ubb knockout mice. Methods: Metabolic rate and energy expenditure were measured in a metabolic chamber, and sleep stage was monitored via electroencephalographic/electromyographic recording. The presence of neurodegeneration and increased reactive gliosis in the hypothalamus were also evaluated. Results: We found that Ubb disruption leads to early‐onset reduced activity and metabolic rate. Additionally, we have demonstrated that sleep behaviour is altered and sleep homeostasis is disrupted in Ubb knockout mice. These early metabolic and sleep abnormalities are accompanied by persistent reactive gliosis and the loss of arcuate nucleus neurones, but are independent of neurodegeneration in the lateral hypothalamus. Conclusions:Ubb knockout mice exhibit phenotypes consistent with hypothalamic dysfunction. Our data also indicate that Ubb is essential for the maintenance of the ubiquitin levels required for proper regulation of metabolic and sleep behaviours in mice.
Toxoplasma gondii is a protozoan parasite with a predation-mediated transmission cycle between rodents and felines. Intermediate hosts acquire Toxoplasma by eating parasite cysts which invade the ...small intestine, disseminate systemically and finally establish host life-long chronic infection in brain and muscles. Here we show that Toxoplasma infection can trigger a severe form of sustained cachexia: a disease of progressive lean weight loss that is a causal predictor of mortality in cancer, chronic disease and many infections. Toxoplasma cachexia is characterized by acute anorexia, systemic inflammation and loss of 20% body mass. Although mice recover from symptoms of peak sickness, they fail to regain muscle mass or visceral adipose depots. We asked whether the damage to the intestinal microenvironment observed at acute time points was sustained in chronic infection and could thereby play a role in sustaining cachexia. We found that parasites replicate in the same region of the distal jejunum/proximal ileum throughout acute infection, inducing the development of secondary lymphoid structures and severe, regional inflammation. Small intestine pathology was resolved by 5 weeks post-infection. However, changes in the commensal populations, notably an outgrowth of Clostridia spp., were sustained in chronic infection. Importantly, uninfected animals co-housed with infected mice display similar changes in commensal microflora but never display symptoms of cachexia, indicating that altered commensals are not sufficient to explain the cachexia phenotype alone. These studies indicate that Toxoplasma infection is a novel and robust model to study the immune-metabolic interactions that contribute to chronic cachexia development, pathology and potential reversal.
N6-methyl-adenosine (m(6)A) is the most abundant modification on messenger RNAs and is linked to human diseases, but its functions in mammalian development are poorly understood. Here we reveal the ...evolutionary conservation and function of m(6)A by mapping the m(6)A methylome in mouse and human embryonic stem cells. Thousands of messenger and long noncoding RNAs show conserved m(6)A modification, including transcripts encoding core pluripotency transcription factors. m(6)A is enriched over 3' untranslated regions at defined sequence motifs and marks unstable transcripts, including transcripts turned over upon differentiation. Genetic inactivation or depletion of mouse and human Mettl3, one of the m(6)A methylases, led to m(6)A erasure on select target genes, prolonged Nanog expression upon differentiation, and impaired ESC exit from self-renewal toward differentiation into several lineages in vitro and in vivo. Thus, m(6)A is a mark of transcriptome flexibility required for stem cells to differentiate to specific lineages.
Group A rotavirus is the leading cause of diarrhea among children aged 3–36 mo worldwide. Introducing fermented milk products into the infant diet has been proposed for the prevention or treatment of ...rotavirus diarrhea. The preventive effect of milk fermented by the Lactobacillus casei strain DN-114 001 was studied in a model of germfree suckling rats supplemented daily from d 2 of life and infected with SA11 rotavirus at d 5 (RF group). One group was supplemented with nonfermented milk (RM) and two uninfected groups (CM and CF) received either nonfermented or fermented milk. Frequency and severity of diarrhea were observed. Rats were killed at various times from 0 to 120 h postinfection (p.i.). Bacteria were measured in the intestine, and rotavirus antigens were detected by ELISA in fecal samples and in different parts of the intestine. Histologic observations were made, including vacuolation, morphology of intestinal villi and number of mucin cells. RM rats had diarrhea for 6 d; compared with the CM group, they had alterations of the intestinal mucosa characterized by cellular vacuolation 48 and 72 h p.i. and a lower number of sulfated mucin cells 72 and 96 h p.i. (P < 0.05). Early supplementation with fermented milk significantly decreased the clinical signs of diarrhea from 24 to 144 h p.i. (P < 0.05) and prevented rotavirus infection in all sections of the intestine. Histologic lesions of the small intestine were greatly reduced (P < 0.05) and the number of mucin cells remained unchanged. The data are discussed with respect to the possibility of reducing rotavirus diarrhea in young children by consumption of fermented milk.
Analyzed endometrial cancer (EC) genomes have allowed for the identification of molecular signatures, which enable the classification, and sometimes prognostication, of these cancers. Artificial ...intelligence algorithms have facilitated the partitioning of mutations into driver and passenger based on a variety of parameters, including gene function and frequency of mutation. Here, we undertook an evaluation of EC cancer genomes deposited on the Catalogue of Somatic Mutations in Cancers (COSMIC), with the goal to classify all mutations as either driver or passenger. Our analysis showed that approximately 2.5% of all mutations are driver and cause cellular transformation and immortalization. We also characterized nucleotide level mutation signatures, gross chromosomal re-arrangements, and gene expression profiles. We observed that endometrial cancers show distinct nucleotide substitution and chromosomal re-arrangement signatures compared to other cancers. We also identified high expression levels of the CLDN18 claudin gene, which is involved in growth, survival, metastasis and proliferation. We then used in silico protein structure analysis to examine the effect of certain previously uncharacterized driver mutations on protein structure. We found that certain mutations in CTNNB1 and TP53 increase protein stability, which may contribute to cellular transformation. While our analysis retrieved previously classified mutations and genomic alterations, which is to be expected, this study also identified new signatures. Additionally, we show that artificial intelligence algorithms can be effectively leveraged to accurately predict key drivers of cancer. This analysis will expand our understanding of ECs and improve the molecular toolbox for classification, diagnosis, or potential treatment of these cancers.
Thermal therapy offers a minimally invasive option for treating benign prostatic hyperplasia (BPH) and localized prostate cancer. In this study we investigated a transurethral ultrasound applicator ...design utilizing curvilinear, or slightly focused, transducers to heat prostatic tissue rapidly and controllably. The applicator was constructed with two independently powered transducer segments operating at 6.5 MHz and measuring
3.5
mm
×
10
mm
with a 15 mm radius of curvature across the short axis. The curvilinear applicator was characterized by acoustic efficiency measurements, acoustic beam plots, biothermal simulations of human prostate, ex vivo heating trials in bovine liver, and in vivo heating trials in canine prostate
(
n
=
3
)
. Each transducer segment was found to emit a narrow acoustic beam
(
max width
<
3
mm
)
, which extended the length of the transducer, with deeper penetration than previously developed planar or sectored tubular transurethral ultrasound applicators. Acoustic and biothermal simulations of human prostate demonstrated three treatment schemes for the curvilinear applicator: single shot (10 W, 60 s) schemes to generate narrow ablation zones (
13
×
4
mm
, 52 °C at the lesion boundary), incremental rotation (10 W,
10
°
∕
45
s
) to generate larger sector-shaped ablation zones (
16
mm
×
180
°
sector), and rotation with variable sonication times (10 W,
10
°
∕
15
–
90
s
) to conform the ablation zone to a predefined boundary (
9
–
17
mm
×
180
°
sector, 13 min total treatment time). During in vivo canine prostate experiments, guided by MR temperature imaging, single shot sonications (
6
W
∕
transducer
, 2–3 min) with the curvilinear applicator ablated 20° sections of tissue to the prostate boundary (9–15 mm). Multiple adjacent sonications (“sweeping”) ablated large sections of the prostate (180°) by using the MR temperature imaging to adjust the power
(
4
–
6.4
W
∕
transducer
)
and sonication time (30–180 s) at each 10° rotation such that the periphery of the prostate reached 52 °C before the next rotation. The conclusion of this study was that the curvilinear applicator produces a narrow and penetrating ultrasound beam that, when combined with image guidance, can provide a precise technique for ablating target regions with a contoured outer boundary, such as the prostate capsule, by rotating in small steps while dynamically adjusting the net applied electrical power and sonication time at each position.
Arginine methylation is a form of posttranslational modification that regulates many cellular functions such as development, DNA damage repair, inflammatory response, splicing, and signal ...transduction, among others. Protein arginine methyltransferase 5 (PRMT5) is one of nine identified methyltransferases, and it can methylate both histone and non-histone targets. It has pleiotropic functions, including recruitment of repair machinery to a chromosomal DNA double strand break (DSB) and coordinating the interplay between repair and checkpoint activation. Thus, PRMT5 has been actively studied as a cancer treatment target, and small molecule inhibitors of its enzymatic activity have already been developed. In this report, we analyzed all reported PRMT5 mutations appearing in cancer cells using data from the Catalogue of Somatic Mutations in Cancers (COSMIC). Our goal is to classify mutations as either drivers or passengers to understand which ones are likely to promote cellular transformation. Using gold standard artificial intelligence algorithms, we uncovered several key driver mutations in the active site of the enzyme (D306H, L315P, and N318K). In silico protein modeling shows that these mutations may affect the affinity of PRMT5 for S-adenosylmethionine (SAM), which is required as a methyl donor. Electrostatic analysis of the enzyme active site shows that one of these mutations creates a tunnel in the vicinity of the SAM binding site, which may allow interfering molecules to enter the enzyme active site and decrease its activity. We also identified several non-coding mutations that appear to affect PRMT5 splicing. Our analyses provide insights into the role of PRMT5 mutations in cancer cells. Additionally, since PRMT5 single molecule inhibitors have already been developed, this work may uncover future directions in how mutations can affect targeted inhibition.
Transurethral ultrasound applicators with highly directional energy deposition and rotational control were investigated for precise treatment of benign prostatic hyperplasia (BPH) and adenocarcinoma ...of the prostate (CaP). Two types of catheter-based applicators were fabricated, using either 90 degrees sectored tubular (3.5 mm OD x 10 mm) or planar transducers (3.5 mm x 10 mm). They were constructed to be MRI compatible, minimally invasive and allow for manual rotation of the transducer array within a 10 mm cooling balloon. In vivo evaluations of the applicators were performed in canine prostates (n = 3) using MRI guidance (0.5 T interventional magnet). MR temperature imaging (MRTI) utilizing the proton resonance frequency shift method was used to acquire multiple-slice temperature overlays in real time for monitoring and guiding the thermal treatments. Post-treatment T1-weighted contrast-enhanced imaging and triphenyl tetrazolium chloride stained tissue sections were used to define regions of tissue coagulation. Single sonications with the 90 degrees tubular applicator (9-15 W, 12 min, 8 MHz) produced coagulated zones covering an 80 degrees wedge of the prostate extending from 1-2 mm outside the urethra to the outer boundary of the gland (16 mm radial coagulation). Single sonications with the planar applicator (15-20 W, 10 min, approximately 8 MHz) generated thermal lesions of approximately 30 degrees extending to the prostate boundary. Multiple sequential sonications (sweeping) of a planar applicator (12 W with eight rotations of 30 degrees each) demonstrated controllable coagulation of a 270 degrees contiguous section of the prostate extending to the capsule boundary. The feasibility of using highly directional transurethral ultrasound applicators with rotational capabilities to selectively coagulate regions of the prostate while monitoring and controlling the treatments with MRTI was demonstrated in this study.
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