Differences in cecal microbiome of selected high and low feather-pecking laying hens

In mammals, it has become increasingly clear that the gut microbiota influences not only gastrointestinal physiology but also modulates behavior. In domestic birds, ceca have the greatest gastrointestinal microbial population. Feather-pecking (FP) behavior in laying hens is one of the most important unsolved behavioral issues in modern agriculture. The aim of the present study was to assess the cecal microbial community of divergently selected high (HFP; n = 20) and low (LFP; n = 20) feather-pecking birds at 60 wk of age. The cecal samples were subjected to community profiling of 16S rRNA and in silico metagenomics using a modified bar-coded Illumina sequencing method on a MiSeq Illumina sequencer. Our results revealed that compared to HFP birds, LFP birds are characterized by an increased overall microbial diversity (beta diversity) shown by a difference in the Bray–Curtis index (R² = 0.171, P < 0.05). Furthermore, operational taxonomic unit comparisons showed an increased presence of Clostridiae and decreased presence of Lactobaccillacae in HFP birds when compared to LFP birds (False Discovery Rate < 0.05, Mann–Whitney comparisons). Our data indicate that there may be differences in the cecal profile between these 2 lines of laying hens. More research, building on this first study using sequencing technology for profiling the chicken cecal microbiome, will be needed in order to reveal if and how there exists a functional link between the performance of FP and the cecal microbial community.

Oxytocin-induced membrane hyperpolarization in pain-sensitive dorsal root ganglia neurons mediated by Ca(2+)/nNOS/NO/KATP pathway

Oxytocin (OT) plays an important role in pain modulation and antinociception in the central nervous system. However, little is known about its peripheral effects. This study was conducted to investigate the effect of OT on the electrical properties of neurons in the dorsal root ganglia (DRG) and the underlying mechanisms. DRG neurons from adult rats were acutely dissociated and cultured. Intracellular Ca(2+) was determined by fluorescent microscopy using an indicator dye. The electrical properties of DRG neurons were tested by patch-clamp recording. The oxytocin receptor (OTR) and neuronal nitric oxide synthase (nNOS) on DRG neurons were assessed with immunofluorescence assays. OTR co-localized with nNOS in most of Isolectin B4 (IB4)-binding cultured DRG neurons in rats. OT decreased the excitability, increased the outward current, and evoked the membrane hyperpolarization in cultured DRG neurons. Sodium nitroprusside (SNP), the donor of nitric oxide (NO), exerted similar effects as OT on the membrane potential of cultured DRG neurons. OT increased the production of NO in DRGs and cultured DRG neurons. Pre-treatment of the OTR antagonist atosiban or the selective nNOS inhibitor N-Propyl-l-arginine (NPLA) significantly attenuated the hyperpolarization effect evoked by OT. OT produced a concentration-dependent increase in intracellular Ca(2+) in DRG neurons that responds to capsaicin, which can be attenuated by atosiban, but not by NPLA. OT-evoked membrane hyperpolarization and increase of outward current were distinctly attenuated by glibenclamide, a blocker of ATP-sensitive K(+) (KATP) channel. OT might be an endogenous antinociceptive agent and the peripheral antinociceptive effects of OT are mediated by activation of the Ca(2+)/nNOS/NO/KATP pathway in DRG neurons.

Oxytocin down-regulates mesenteric afferent sensitivity via the enteric OTR/nNOS/NO/KATP pathway in rat

BACKGROUND

Oxytocin plays an analgesic role in modulation of nociception and pain. Most work to date has focused on the central mechanisms of oxytocin analgesia, but little is known about whether peripheral mechanisms are also involved.

METHODS

The mesenteric afferent discharge was recorded in vitro. The expressions of oxytocin receptor (OTR) and neuronal nitric oxide synthase (nNOS) in longitudinal muscle myenteric plexus (LMMP) was identified by immunofluorescence.

KEY RESULTS

Oxytocin per se had no effect on the jejunal mesenteric afferent discharge, however, it markedly attenuated the bradykinin- or distention-evoked increase of mesenteric afferent discharge, which was mimiced by the nitric oxide (NO) donor sodium nitroprusside (SNP). Pretreatment of either NOS inhibitor L-NAME or NPLA largely reduced the inhibitory effect of oxytocin on bradykinin-evoked mesenteric afferent discharge. Such effect, to a large extent, was also alleviated by N-and P-type voltage-dependent calcium channel antagonists or KATP blocker glibenclamide. In addition, immunofluorescence studies show strong colocalization of OTR with nNOS in LMMP of the rat jejunum.

CONCLUSIONS & INFERENCES

Oxytocin down-regulates the mesenteric afferent sensitivity through nNOS-NO-KATP pathway. Our findings may reveal a new peripheral mechanism for oxytocin analgesia.

Bifidobacterium longum NCC3001 inhibits AH neuron excitability

BACKGROUND

Bifidobacterium longum (B. longum) NCC3001 can affect behavior and brain biochemistry, but identification of the cellular targets needs further investigation. Our hypothesis was that the communication with the brain might start with action on enteric sensory neurons.

METHODS

Ileal segments from adult mice were used to create a longitudinal muscle-myenteric-plexus preparation to expose sensory after-hyperpolarizing (AH) neurons in the myenteric plexus to allow access with microelectrodes. The intrinsic excitability of AH neurons was tested in response to the perfusion of conditioned media (B. longum culture supernatant) or unconditioned media (growth medium, MRS).

KEY RESULTS

B. longum conditioned medium significantly reduced the excitability of AH neurons compared to perfusion with the unconditioned medium. Specifically, a reduction was seen in the number of action potentials fired per depolarizing test pulse, the instantaneous and time-dependent input resistances and the magnitude of the hyperpolarization-activated cationic current (Ih ).

CONCLUSIONS & INFERENCES

The probiotic B. longum reduces excitability of AH sensory neurons likely via opening of potassium channels and closing of hyperpolarization-activated cation channels.

The microbiota and the gut-brain axis: insights from the temporal and spatial mucosal alterations during colonisation of the germfree mouse intestine

The influence of the gut microbiota on the nervous system, brain development and behaviour, in particular during microbial colonisation of the host, has recently been receiving profound interest. Our time-resolved mining of combined data analyses of the ex-germfree mouse intestine during a 30-day course of colonisation with conventional mouse faecal microbiota (conventionalisation), shed light on temporal altered expression of genes of which the products influenced functions of the nervous system. Plasma tryptophan and kynurenine levels reflected high indoleamine dioxygenase activity, which was supported by significant temporal induction of the encoding gene in all gut tissues. However, the majority of genes associated with neuronal development and function were reduced. Colonic substance P elevation in response to conventionalisation was higher only after 30-days. These results support a functional microbiota-neurohumoral relationship during conventionalisation and suggest a delayed neuronal response that is elicited only after the microbiota accommodating homeostasis has been accomplished.

The anxiolytic effect of Bifidobacterium longum NCC3001 involves vagal pathways for gut-brain communication

BACKGROUND

The probiotic Bifidobacterium longum NCC3001 normalizes anxiety-like behavior and hippocampal brain derived neurotrophic factor (BDNF) in mice with infectious colitis. Using a model of chemical colitis we test whether the anxiolytic effect of B. longum involves vagal integrity, and changes in neural cell function. Methods  Mice received dextran sodium sulfate (DSS, 3%) in drinking water during three 1-week cycles. Bifidobacterium longum or placebo were gavaged daily during the last cycle. Some mice underwent subdiaphragmatic vagotomy. Behavior was assessed by step-down test, inflammation by myeloperoxidase (MPO) activity and histology. BDNF mRNA was measured in neuroblastoma SH-SY5Y cells after incubation with sera from B. longum- or placebo-treated mice. The effect of B. longum on myenteric neuron excitability was measured using intracellular microelectrodes.

KEY RESULTS

Chronic colitis was associated with anxiety-like behavior, which was absent in previously vagotomized mice. B. longum normalized behavior but had no effect on MPO activity or histological scores. Its anxiolytic effect was absent in mice with established anxiety that were vagotomized before the third DSS cycle. B. longum metabolites did not affect BDNF mRNA expression in SH-SY5Y cells but decreased excitability of enteric neurons.

CONCLUSIONS & INFERENCES

In this colitis model, anxiety-like behavior is vagally mediated. The anxiolytic effect of B. longum requires vagal integrity but does not involve gut immuno-modulation or production of BDNF by neuronal cells. As B. longum decreases excitability of enteric neurons, it may signal to the central nervous system by activating vagal pathways at the level of the enteric nervous system.

Lactobacillus reuteri ingestion and IK(Ca) channel blockade have similar effects on rat colon motility and myenteric neurones

BACKGROUND

We have previously shown that ingestion of Lactobacillus reuteri may modulate colonic enteric neuron activity but with unknown effects on colon motility. The aim of the present report was to elucidate the neuronal mechanisms of action of the probiotic by comparing the effects on motility of L. reuteri ingestion with blockade of a specific ionic current in enteric neurons.

METHODS

We have used intraluminal pressure recordings from ex vivo rat colon segments and whole cell patch clamp recordings from neurons of rat longitudinal muscle myenteric plexus preparations to investigate the effects of L. reuteri and TRAM-34 on colon motility and neurophysiology. The effects of daily feeding of 10(9) L. reuteri bacteria or acute application of TRAM-34 on threshold fluid filling pressure or pulse pressure was measured.

KEY RESULTS

Lactobacillus reuteri increased intraluminal fluid filling pressure thresholds for evoking pressure pulses by 51% from 0.47 +/- 0.17 hPa; the probiotic also decreased the pulse pressure amplitudes, but not frequency, by 18% from 3.91 +/- 0.52 hPa. The intermediate conductance calcium-dependent potassium (IK(Ca)) channel blocker TRAM-34 (3 micromol L(-1)) increased filling threshold pressure by 43% from 0.52 +/- 0.22 hPa and reduced pulse pressure amplitude by 40% from 2.63 +/- 1.11 hPa; contraction frequency was unaltered. TRAM-34 (3 micromol L(-1)) reduced membrane polarization, leak conductance and the slow afterhyperpolarization current in 16/16 myenteric rat colon AH cells but 19/19 S cells were unaffected.

CONCLUSIONS & INFERENCES

The present results are consistent with L. reuteri enhancing tonic inhibition of colon contractile activity by acting via the IK(Ca) channel current in AH cells.

Recurrent posttraumatic meningitis due to nontypable Haemophilus influenzae: case report and review of the literature

We report a case of relapsing Haemophilus influenzae meningitis in a boy at the age of nearly 3 years and 4.2 years who had been successfully vaccinated against H. influenzae serotype b (Hib). The pathogen was a nonencapsulated (nontypable) H. influenzae strain of biotypes III and VI, respectively. A rhinobasal impalement injury with development of a posttraumatic encephalocele is considered to be the predisposing condition. Review of the literature reveals that in patients systemically infected by nonencapsulated H. influenzae strains predisposing factors such as cerebrospinal fluid-shunts, implants and traumas are often found. To obtain further information on potential new disease patterns H. influenzae isolates from cerebrospinal fluid should be examined for capsule production and, if relevant, further characterized by capsular typing.

Nitric oxide mediates the inhibitory effect of ethanol on the motility of isolated longitudinal muscle of proximal colon in rats

The aim of the present study was to investigate the effect of ethanol on colon motility in rats and to test the possibility that nitric oxide (NO) mediates this effect. Proximal colon longitudinal muscle strips (LM) (8 x 3 mm) cut parallel to the longitudinal muscle fibres of the colon were isolated and mounted in an organ bath. Ethanol (0.57, 0.87 and 1.30 mmol L(-1)) dose-dependently inhibited the motility of LM. Longitudinal muscle strips from female rats were more sensitive to the inhibitory effect of ethanol than that from male rats. L-NAME (N-nitro-L-arginine methyl ester) (100 micromol L(-1)), AG (aminoguanidine) (10 micromol L(-1)), ODQ (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one) (10 micromol L(-1)) and PTIO (2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide) (200 micromol L(-1)) partly blocked the inhibitory effect of ethanol on LM. Pretreatment with L-NAME, AG, ODQ and PTIO abolished the sex difference of the inhibitory effect of ethanol on LM. Tetrodotoxin (TTX) (10 micromol L(-1)) partly blocked the inhibitory effect but did not influence the sex difference. The relaxation of LM induced by SNP (sodium nitroprusside) (0.1-10 micromol L(-1)) in female rats was greater than that in male rats. In conclusion, ethanol inhibited the colon motility in vitro. This inhibitory effect on LM was mediated by NO through the iNOS - NO - cGMP pathway.

[Urinary secretory immunoglobulin A in urinary tract infections in childhood]

The pathogenesis of urinary tract infections is not yet sufficiently explained despite of large progressions in this field. A special disposition for infections of the kidneys and the urinary tract more and more be seen not only as an anatomic and/or urodynamic but also as an immunologic problem. The secretory immunoglobulin A (S-IgA) in the urine is a measurable parameter for the function of the local immuno system of the mucous membranes in the urogenital system being subject of the present investigations. 87 children with different forms and stages of activity of the urinary tract infection and 59 healthy children have been chosen in order to measure the concentration and the excretion of S-IgA (mg S-IgA/g creatinine). The S-IgA is estimated by an enzyme immunoassay. We have found that the concentration, the excretion and the daily excretion of S-IgA are higher in all forms of pyelonephritis in an acute stage compared with healthy volunteers. There is a non-significant decrease of these values during an antibiotic therapy. It is evident that the values of patients with chronic pyelonephritis have been significantly diminished during the symptom-free interval compared with healthy volunteers (p less than 0.05). Considering the literature our results show that the function of the kidneys as well as inflammation and local immunity are in a close correlation.

[Determination of secretory immunoglobulin A in urine of children with enzyme immunoassay]

The estimation of secretory immunoglobulin A (sIgA) by an enzyme immunoassay (EIA) was used as heterogenic solid-phase assay. A monoclonal antibody directed against the human secretoric part and a peroxidase-marked anti-IgA serum may mediate the reaction. The test was evaluated on urine of 59 healthy children aged from 0-14 years. An age-dependent increase of sIgA concentration (mg/l) and excretion up to the 6th months of life was found. Thereafter the concentration did reach a constant value of 0.5 mg/l sIgA and 0.4 mg sIgA/g creatinine, respectively. The normal values may follow a logarithmic distribution. The presented method is highly sensitive, simple and safe.

[Rubella virus infection as a cause of nephrosis in infancy]

There is obtained the rare disease of the nephrotic syndrome in an infant during the first year of life. The diagnosis of symptomatic nephrosis in the course of an infection with Rubellavirus was postulated on the basis of clinical and serological results. The heterogenous signs of the nephrosis in the first year of life, the possible causes, the treatment and the prognosis are discussed.

An electrophysiological study of thalamo-caudate neurones in the cat

Thalamo-caudate projection neurones were identified in cats by antidromic activation from the caudate nucleus, under chloralose anaesthesia or in cerveau isolé preparations. Units in nuclei centralis lateralis, medialis dorsalis, and centrum medianum-parafascicularis responded antidromically to one or more electrodes of a caudate nucleus array at latencies ranging from 0.4 to 16 ms. The responses did not appear to result from stimulus spread to the internal capsule. A separate population of medial thalamic units responded postsynaptically to caudate stimulation, at modal latency exceeding modal antidromic latency by 2 ms. Comparison of apparent conduction velocities for each thalamic nucleus indicated that the postsynaptic responses were activated by collaterals of thalamo-caudate neurones. A proportion of thalamo-caudate neurones responded to somatic stimulation; some of these were inhibited by caudate stimulation, and a few discharged on substantia nigra stimulation. These results demonstrate the possibility of somatic afferent and nigrofugal inputs to the caudate nucleus mediated by neurones of the medial thalamus.