Effect of guaianolides in the meiosis reinitiation of amphibian oocytes.

Sesquiterpene lactones (STLs) are a large and structurally diverse group of plant metabolites generally found in the Asteraceae family. STLs exhibit a wide spectrum of biological activities and it is generally accepted that their major mechanism of action is the alkylation of the thiol groups of biological molecules. The guaianolides is one of various groups of STLs. Anti-tumour and anti-migraine effects, an allergenic agent, an inhibitor of smooth muscle cells and of meristematic cell proliferation are only a few of the most commonly reported activities of STLs. In amphibians, fully grown ovarian oocytes are arrested at the beginning of meiosis I. Under stimulus with progesterone, this meiotic arrest is released and meiosis progresses to metaphase II, a process known as oocyte maturation. There are previous records of the inhibitory effect of dehydroleucodin (DhL), a guaianolide lactone, on the progression of meiosis. It has been also shown that DhL and its 11,13-dihydroderivative (2H-DhL; a mixture of epimers at C-11) act as blockers of the resumption of meiosis in fully grown ovarian oocytes from the amphibian Rhinella arenarum (formerly classified as Bufo arenarum). The aim of this study was to analyze the effect of four closely related guaianolides, i.e., DhL, achillin, desacetoxymatricarin and estafietin as possible inhibitors of meiosis in oocytes of amphibians in vitro and discuss some structure-activity relationships. It was found that the inhibitory effect on meiosis resumption is greater when the lactone has two potentially reactive centres, either a α,ß-α',ß'-diunsaturated cyclopentanone moiety or an epoxide group plus an exo-methylene-γ-lactone function.

Identification of an anti-inflammatory protein from Faecalibacterium prausnitzii, a commensal bacterium deficient in Crohn's disease.

BACKGROUND: Crohn's disease (CD)-associated dysbiosis is characterised by a loss of Faecalibacterium prausnitzii, whose culture supernatant exerts an anti-inflammatory effect both in vitro and in vivo. However, the chemical nature of the anti-inflammatory compounds has not yet been determined. METHODS: Peptidomic analysis using mass spectrometry was applied to F. prausnitzii supernatant. Anti-inflammatory effects of identified peptides were tested in vitro directly on intestinal epithelial cell lines and on cell lines transfected with a plasmid construction coding for the candidate protein encompassing these peptides. In vivo, the cDNA of the candidate protein was delivered to the gut by recombinant lactic acid bacteria to prevent dinitrobenzene sulfonic acid (DNBS)-colitis in mice. RESULTS: The seven peptides, identified in the F. prausnitzii culture supernatants, derived from a single microbial anti-inflammatory molecule (MAM), a protein of 15 kDa, and comprising 53% of non-polar residues. This last feature prevented the direct characterisation of the putative anti-inflammatory activity of MAM-derived peptides. Transfection of MAM cDNA in epithelial cells led to a significant decrease in the activation of the nuclear factor (NF)-κB pathway with a dose-dependent effect. Finally, the use of a food-grade bacterium, Lactococcus lactis, delivering a plasmid encoding MAM was able to alleviate DNBS-induced colitis in mice. CONCLUSIONS: A 15 kDa protein with anti-inflammatory properties is produced by F. prausnitzii, a commensal bacterium involved in CD pathogenesis. This protein is able to inhibit the NF-κB pathway in intestinal epithelial cells and to prevent colitis in an animal model.

Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery.

BACKGROUND: Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD. RESULTS: The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota. CONCLUSIONS: Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice. Video Abstract.

Over-production of exopolysaccharide by Lacticaseibacillus rhamnosus CNCM I-3690 strain cutbacks its beneficial effect on the host.

Most lactobacilli produce extracellular polysaccharides that are considered to contribute to the probiotic effect of many strains. Lacticaseibacillus rhamnosus CNCM I-3690 is an anti-inflammatory strain able to counterbalance gut barrier dysfunction. In this study ten spontaneous variants of CNCM I-3690 with different EPS-production were generated and characterized by their ropy phenotype, the quantification of the secreted EPS and genetic analysis. Amongst them, two were further analysed in vitro and in vivo: an EPS over-producer (7292) and a low-producer derivative of 7292 (7358, with similar EPS levels than the wild type (WT) strain). Our results showed that 7292 does not have anti-inflammatory profile in vitro, and lost the capacity to adhere to the colonic epithelial cells as well as the protective effect on the permeability. Finally, 7292 lost the protective effects of the WT strain in a murine model of gut dysfunction. Notably, strain 7292 was unable to stimulate goblet cell mucus production and colonic IL-10 production, all key features for the beneficial effect of the WT strain. Furthermore, transcriptome analysis of colonic samples from 7292-treated mice showed a down-regulation of anti-inflammatory genes. Altogether, our results point out that the increase of EPS production in CNCM I-3690 impairs its protective effects and highlight the importance of the correct EPS synthesis for the beneficial effects of this strain.

Maternal dietary omega-3 deficiency worsens the deleterious effects of prenatal inflammation on the gut-brain axis in the offspring across lifetime.

Maternal immune activation (MIA) and poor maternal nutritional habits are risk factors for the occurrence of neurodevelopmental disorders (NDD). Human studies show the deleterious impact of prenatal inflammation and low n-3 polyunsaturated fatty acid (PUFA) intake on neurodevelopment with long-lasting consequences on behavior. However, the mechanisms linking maternal nutritional status to MIA are still unclear, despite their relevance to the etiology of NDD. We demonstrate here that low maternal n-3 PUFA intake worsens MIA-induced early gut dysfunction, including modification of gut microbiota composition and higher local inflammatory reactivity. These deficits correlate with alterations of microglia-neuron crosstalk pathways and have long-lasting effects, both at transcriptional and behavioral levels. This work highlights the perinatal period as a critical time window, especially regarding the role of the gut-brain axis in neurodevelopment, elucidating the link between MIA, poor nutritional habits, and NDD.

A comprehensive transcriptomic analysis of the effect of silicon on wheat plants under control and pathogen stress conditions.

The supply of soluble silicon (Si) to plants has been associated with many benefits that remain poorly explained and often contested. In this work, the effect of Si was studied on wheat plants under both control and pathogen stress (Blumeria graminis f. sp. tritici) conditions by conducting a large transcriptomic analysis (55,000 unigenes) aimed at comparing the differential response of plants under four treatments. The response to the supply of Si on control (uninfected) plants was limited to 47 genes of diverse functions providing little evidence of regulation of a specific metabolic process. Plants reacted to inoculation with B. graminis f. sp. tritici by an upregulation of many genes linked to stress and metabolic processes and a downregulation of genes linked to photosynthesis. Supplying Si to inoculated plants largely prevented disease development, a phenotypic response that translated into a nearly perfect reversal of genes regulated by the effect of B. graminis f. sp. tritici alone. These results suggest that Si plays a limited role on a plant's transcriptome in the absence of stress, even in the case of a high-Si-accumulating monocot such as wheat. On the other hand, the benefits of Si in the form of biotic stress alleviation were remarkably aligned with a counter-response to transcriptomic changes induced by the pathogen B. graminis f. sp. tritici.

Identification of genes potentially involved in the biocontrol activity of Pseudozyma flocculosa.

Flocculosin is an antifungal cellobiose lipid linked to the biocontrol activity of Pseudozyma flocculosa and whose structure is very similar to that of ustilagic acid produced by Ustilago maydis. In this work, homologs of the U. maydis cyp1 gene, involved in the biosynthesis of ustilagic acid, were isolated and sequenced from P. flocculosa and P. fusiformata, the latter species being also known to produce ustilagic acid. Interestingly, no homologs were found in four other closely related Pseudozyma spp. from which no evidence of ustilagic acid production has ever been obtained, thus supporting the specificity of cyp1 with ustilagic acid synthesis. In addition, a homolog of the U. maydis uat1 gene involved in the acetylation of the molecule and located next to the cyp1 gene was partially sequenced from P. flocculosa. All three newly sequenced genes showed strong sequence similarity to their counterparts in U. maydis. Cyp1 expression was monitored in conditions that were either conducive or repressive to flocculosin production. Expression increased markedly (>100x) when P. flocculosa was inoculated in a growth medium conducive to flocculosin production but was rapidly downregulated in a repressive medium (in vitro) or on powdery mildew-infected cucumber leaves (in vivo). This suggests that the molecule was preferentially synthesized early in the process of searching for a growth substrate. This study provides the first identification of genes involved in the production of flocculosin, a molecule potentially associated with the biocontrol properties of P. flocculosa.

Opposing effect of Lactobacillus on in vitro Klebsiella pneumoniae in biofilm and in an in vivo intestinal colonisation model.

Beneficial bacteria represent potential sources of therapy, particularly in the battle against antibiotic-resistant pathogens. The Gram-negative bacillus Klebsiella pneumoniae is not only a paradigm of multi-resistant opportunistic pathogen, but it is also able to colonise the human intestine and displays a high capacity to form biofilm. In this study, the anti-biofilm activity of 140 neutralised Lactobacillus supernatants was assessed against K. pneumoniae. Among the 13 strains whose supernatant significantly impaired biofilm formation, Lactobacillus plantarum CIRM653 was selected because it was also able to impair K. pneumoniae preformed biofilm, independently of a bactericidal effect. Mixed K. pneumoniae/L. plantarum CIRM653 biofilms had reduced tridimensional structures associated with a significant decrease in K. pneumoniae biomass. Further investigation showed that L. plantarum CIRM653 supernatant induced transcriptional modifications of K. pneumoniae biofilm-related genes, including down-regulation of the quorum sensing-related lsr operons and over-expression of type 3 pili structure genes. Increased production of type 3 pili was validated by Western-blot, hemagglutination and adhesion assays. L. plantarum CIRM653 activity against K. pneumoniae was also assessed in a murine intestinal colonisation model: a constant faecal pathogen burden was observed, as against a gradual decrease in the control group. These results reveal that an in vitro a priori attracting anti-biofilm activity of Lactobacillus might be counterbalanced by an in vivo behaviour in a complex microbiota environment with potential deleterious dispersal of highly adherent K. pneumoniae cells, raising the question of the accuracy of in vitro assays in screening of beneficial microbes.

Lactobacillus rhamnosus CNCM I-3690 and the commensal bacterium Faecalibacterium prausnitzii A2-165 exhibit similar protective effects to induced barrier hyper-permeability in mice.

Impaired gut barrier function has been reported in a wide range of diseases and syndromes and in some functional gastrointestinal disorders. In addition, there is increasing evidence that suggests the gut microbiota tightly regulates gut barrier function and recent studies demonstrate that probiotic bacteria can enhance barrier integrity. Here, we aimed to investigate the effects of Lactobacillus rhamnosus CNCM I-3690 on intestinal barrier function. In vitro results using a Caco-2 monolayer cells stimulated with TNF-α confirmed the anti-inflammatory nature of the strain CNCM I-3690 and pointed out a putative role for the protection of the epithelial function. Next, we tested the protective effects of L. rhamnosus CNCM I-3690 in a mouse model of increased colonic permeability. Most importantly, we compared its performance to that of the well-known beneficial human commensal bacterium Faecalibacterium prauznitzii A2-165. Increased colonic permeability was normalized by both strains to a similar degree. Modulation of apical tight junction proteins expression was then analyzed to decipher the mechanism underlying this effect. We showed that CNCM I-3690 partially restored the function of the intestinal barrier and increased the levels of tight junction proteins Occludin and E-cadherin. The results indicate L. rhamnosus CNCM I-3690 is as effective as the commensal anti-inflammatory bacterium F. prausnitzii to treat functional barrier abnormalities.

Unilateral visual neglect and wave P 300. A study of nine cases with unilateral lesions of the parietal lobes.

Wave P 300 was studied in nine patients with parietal lobe lesions who had visual neglect but no hemianopia. Stimulation of the hemispace contralateral to the lesion showed a lengthening in latency and a decrease in amplitude of P 300, specifically related to visual stimulation. Comparison with results obtained in 14 normal subjects and four patients with localized hemispheric lesions without visual neglect showed that changes in P 300 were specifically related to visual neglect. The parietal lobe lesions may disturb cerebral processes involved in discrimination and visual stimulus evaluation required to perform a task, inducing disturbance of the system responsible for P 300.

Miller Fisher syndrome: clinical and electrophysiologic evidence of peripheral origin in 10 cases.

Clinical and electrophysiologic data recorded in patients with Fisher syndrome characterized by ophthalmoplegia, ataxia, and areflexia are presented. Cases with limb weakness or pleocytosis in the CSF were excluded, according to Fisher. Ten patients were selected. All had hand and foot numbness. A large amount of protein without cell reaction was found during the third week of illness in serial CSF examinations. EMGs showed very slight limb involvement without spontaneous activity, and in most cases, facial muscles exhibited a denervation pattern. Distal motor nerve conduction velocity on limbs and F wave latencies were normal, whereas the sensory nerve action potentials were altered in all but one case when tested (seven out of eight cases). By means of blink reflex study performed in four patients, no significant pattern of brainstem dysfunction was discovered. The authors discuss the preeminent role of peripheral nerve lesions with regard to the ataxia and ophthalmoplegia.

Dissecting aneurysm of the vertebral artery and cervical manipulation: a case report with autopsy.

A 35-year-old woman with 3 weeks of cervical pain developed ischemia in the basilar artery territory following cervical manipulation. At autopsy, there was a dissecting aneurysm within the third segment of the right vertebral artery. The pathologic changes in the lower and the upper part of the dissecting aneurysm were different, indicating recurring bleeding. Cervical manipulation could have accounted for one recent dissection, but not for another, which was a few weeks old. This suggests that cervical pain, which prompted the manipulation, may have been the first symptom of the dissection, and manipulation of the neck precipitated the stroke by inducing bleeding within the dissecting aneurysm.

Manic-like state after bilateral orbitofrontal and right temporoparietal injury: efficacy of clonidine.

A manic-like state occurred in a 44-year-old right-handed woman with bilateral orbitofrontal and right temporoparietal traumatic contusions. In a brief trial, we assessed the effect of clonidine, carbamazepine, dopa therapy, and placebo on manic symptoms and cognitive functions. Clonidine rapidly reversed the manic syndrome. The patient's behavior did not change with carbamazepine and worsened with levodopa. We suggest that the manic-like syndrome was related to noradrenergic overactivity secondary to the fronto-orbital lesions.

Recovery from nonfluent aphasia after melodic intonation therapy: a PET study.

We examined mechanisms of recovery from aphasia in seven nonfluent aphasic patients, who were successfully treated with melodic intonation therapy (MIT) after a lengthy absence of spontaneous recovery. We measured changes in relative cerebral blood flow (CBF) with positron emission tomography (PET) during hearing and repetition of simple words, and during repetition of MIT-loaded words. Without MIT, language tasks abnormally activated right hemisphere regions, homotopic to those activated in the normal subject, and deactivated left hemisphere language zones. In contrast, repeating words with MIT reactivated Broca's area and the left prefrontal cortex, while deactivating the counterpart of Wernicke's area in the right hemisphere. The recovery process induced by MIT in these patients probably coincides with this reactivation of left prefrontal structures. In contrast, the right hemisphere regions abnormally activated during simple language tasks seem to be associated with the initial persistence of the aphasia. This study supports the idea that abnormal activation patterns in the lesioned brain are not necessarily related to the recovery process.

A study of visual processes in a case of interhemispheric disconnexion.

A 75-year-old right-handed woman, after a probable cerebral infarct, developed an irregular constriction of the visual fields, a left-sided agraphia, and an anomia for objects in the left hand. Subsequent testing demonstrated an inability to name, though ability to recognize, letters and objects flashed in the homonymous left visual field. An inter-hemispheric disconnexion syndrome was inferred from these findings. The present publication concerns mainly the visual aspects of this disconnexion syndrome. Tasks were devised to test the abilities of the major and minor hemisphere: (a) the left hemisphere demonstrated a complete dominance for language expression and an incomplete dominance for written language comprehension; (b) the right hemisphere appeared to be dominant for some visuo-spatial tasks including number comprehension; (c) when the hemispheres were given contradictory visual informations on a non-verbal task (chimeric stimuli) there was a predominance of the right hemisphere. The right hemisphere appeared able to process complex information. Specialization of functional activities in each hemisphere is briefly discussed.

Serum and CSF humoral immunity in Guillain-Barré syndrome: clinical correlations.

Paired samples of CSF and serum obtained from 29 patients affected with Guillain-Barré syndrome (GBS) were analyzed for various protein levels, including immunoglobulins and complement components. An attempt was made to correlate these findings to the clinical stage, severity, and duration of the disease. Intrathecal IgG synthesis was detected and quantified by means of a previously reported formula. It is practically constant in the GBS during the stage of stabilized paralysis, and is significantly greater in this stage than in the stage of progressive paralysis. Moreover, it increases with severity and duration (longer than 3 months) of the disease. Evidence of intrathecal C3 consumption is also presented.

[Complete human Klüver-Bucy syndrome after encephalitis caused by herpes simplex type 2]. / Syndrome de Klüver-Bucy humain complet après une encéphalite à herpès simplex type 2.

A case of complete Klüver-Bucy syndrome is reported. A 42 year-old man developed Herpes Simplex type II (H.S.V.II) encephalitis. Good sparing of language functions allowed thorough neuropsychological testing. The troubles usually described in Klüver-Bucy syndrome as psychic blindness, colour agnosia, prosopagnosia, auditive and tactile agnosia were present. The authors theorize that these symptoms are mainly correlated with the amnestic syndrome, which is constantly reported in human Klüver-Bucy syndrome. Unfortunately, after 8 weeks, the encephalitis recurred and the patient was left demented and untestable.

[Recording of visual evoked potentials in the diagnosis of multiple sclerosis]. / Apport de l'enregistrement des potentiels évoqués visuels au diagnostic de la sclérose en plaques

The authors report the results of recording EVP obtained by pattern reversal in 20 controls and 43 patients with "established", "probable" or "possible" MS on the basis of MacAlpine's criteria. Whilst the latency of the wave 1 of the EVP appeared stable in the controls (107.5 msec +/- 7.46), lengthening of the latency of the EVP was seen in 77p. 100 of cases, confirming involvement of the visual pathways, though bulbar neuritis had been known clinically in only 28 p. 100 of patients. The value of this method of recording EVP in contributing to the diagnosis of DS is discussed.

[The pontine reticular formation syndrome. Physiopathologic data on voluntary eye movement abnormalities]. / Syndrome de la formation réticulaire pontique. Précisions physiopathologiques sur les anomalies des mouvements oculaires volontaires.

A new clinical case of Pontine Reticular Formation (P.R.F.) syndrome is reported and analysed using electro-oculograms. The CAT scan showed a probably metastatic tumour, clearly limited and located in the ventral part of the left tegmentum in the lower pons. The oculomotor disorders were typical of the P.R.F. syndrome and similar to those previously reported in pathological studies. The left P.R.F. damage was clinically evidenced by the loss of all leftward saccades (voluntary saccades and quick phases of nystagmus), including also those situated in the right hemifield of movement. It was noticed that the voluntary return movement driving both eyes from the right lateral position to the midline was remarkably slow and twice slower for the left eye (10 degrees/s) than for the right one (20 degrees/s). The loss of pursuit movements in the left hemifield of movement suggested that the lower part of the left P.R.F. was affected by the lesion. The preservation of normal leftward oculocephalic movements for the right eye indicated that the left abducens nucleus was spared. Lastly, the complete abductive paralysis of the left eye including the oculocephalic movement implied that the left abducens motoneurons passing through the lower part of the P.R.F. were damaged. All these functional and structural correlates are consistent with the location of the lesion given by the CAT scan. They are reviewed in the light of recent experimental and clinico-pathological data. A detailed physiopathological interpretation accounting for the slow voluntary movements, observed in place of the leftward return saccades in the right hemifield of movement, is proposed. The slowness of the movements of both eyes results from lack of phasic excitation of the motoneurons of the agonist muscles and from lack of phasic inhibition of the motoneurons of the antagonist muscles, both mechanisms being suppressed by the lesion which damages the excitatory burst neurons of the left P.R.F. As the tonic cells of the left P.R.F. are also out of action, these slow movements could mainly be controlled by the tonic cells of the right P.R.F. For the left eye, as the root fibres of the left abducens nucleus are damaged, no excitation can occur on the agonist muscle (left lateral rectus) and there is only a voluntary tonic disfacilitation of the motoneurons of the antagonist muscle (left medial rectus). For the right eye, the same mechanism involving the antagonist muscle (right lateral rectus) would be combined with some tonic excitation of the motoneurons of the agonist muscle (right medial rectus), thus accounting for the twice faster velocity of this eye. This tonic excitation reaching the right medial rectus could be mediated either by one of the other afferent neurons of the left abducens nucleus encoding eye position--namely those arising from the vestibular nuclei or from both prepositus hypoglossi nuclei--or by the right ascending tract of Deiters projecting to the right medial rectus motoneurons.