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Contamination by uranium (U) occurs principally at U mining and processing sites. Uranium can have tremendous environmental consequences, as it is highly toxic to a broad range of organisms and can be dispersed in both terrestrial and aquatic environments. Remediation strategies of U-contaminated soils have included physical and chemical procedures, which may be beneficial, but are costly and can lead to further environmental damage. Phytoremediation has been proposed as a promising alternative, which relies on the capacity of plants and their associated microorganisms to stabilize or extract contaminants from soils. In this paper, we review the role of a group of plant symbiotic fungi, i.e. arbuscular mycorrhizal fungi, which constitute an essential link between the soil and the roots. These fungi participate in U immobilization in soils and within plant roots and they can reduce root-to-shoot translocation of U. However, there is a need to evaluate these observations in terms of their importance for phytostabilization strategies.

This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies.

We investigated genetic variation in asexual polyploid members of the water flea Daphnia pulex complex from a set of 12 Bolivian high-altitude lakes. We used nuclear microsatellite markers to study genetic relationships among all encountered multilocus genotypes, and combined this with a phylogenetic approach using DNA sequence data of three mitochondrial genes. Analyses of mitochondrial gene sequence divergence showed the presence of three very distinct clades that likely represent cryptic undescribed species. Our phylogenetic results suggest that the Daphnia pulicaria group, a complex of predominantly North American species that has diversified rapidly since the Pleistocene, has its origin in South America, as specific tests of topology indicated that all three South American lineages are ancestral to the North American members of this species group. A comparison between variation of nuclear and mitochondrial markers revealed that closely related polyploid nuclear genotypes sometimes belonged to very divergent mitochondrial lineages, while distantly related nuclear genotypes often belonged to the same mitochondrial lineage. This discrepancy suggests that these South American water fleas originated through reciprocal hybridization between different endemic, sexually reproducing parental lineages. It is also likely that polyploidy of the investigated lineages resulted from this hybridization. Nevertheless, no putative diploid parental lineages were found in the studied region.

Background: During the course of their disease, about 30% of patients with ulcerative colitis (UC) will undergo proctocolectomy with ileal pouch-anal anastomosis (IPAA). We evaluated the outcome of IPAA in a Belgian referral center., Methods: Clinical charts were reviewed for pre- and postoperative disease course, functional outcome, and complications in all patients with UC (n = 182) and indeterminate colitis (n = 2) who underwent IPAA in 1990-2004., Results: Follow-up data were available in 173 out of 184 patients (67 female, median age at proctocolectomy 39.0 years). Median functional Oresland score 1 year after IPAA was 3 (range 0-11). Early postoperative complications were seen in 27% of patients. After a median (interquartile range) follow-up of 6.5 (3.4-9.9) years, 35% of patients developed septic and/or obstructive complications. Forty-six percent of patients developed at least 1 episode of pouchitis. Risk factors for pouchitis were the presence of extraintestinal manifestations (odds ratio [OR] 1.92 (1.23-3.01), P = 0.004) and younger age at proctocolectomy (P = 0.004). Chronic pouchitis was present in 33 patients and associated with extraintestinal manifestations (OR 2.93 (1.13-7.62), P = 0.027), backwash ileitis (OR 9.28 (1.71-50.49), P = 0.010), and length of follow-up (P = 0.004). Pouch failure occurred in 5% of patients., Conclusions: Although proctocolectomy with IPAA surgery has a good functional outcome, postoperative complications, especially pouchitis, remain considerable in patients with UC.

There is a vivid debate on the relative importance of local and regional factors in shaping microbial communities, and on whether microbial organisms show a biogeographic signature in their distribution. Taking a metacommunity approach, spatial factors can become important either through dispersal limitation (compare large spatial scales) or mass effects (in case of strongly connected systems). We here analyze two datasets on bacterial communities [characterized by community fingerprinting through denaturing gradient gel electrophoresis (DGGE)] in meso- to eutrophic shallow lakes to investigate the importance of spatial factors at three contrasting scales. Variation partitioning on datasets of both the bacterial communities of 11 shallow lakes that are part of a strongly interconnected and densely packed pond system <1 km apart, three groups of shallow lakes approximately 100 km apart, as well as these three groups of shallow lakes combined that span a large part of a North-South gradient in Europe (>2,500 km) shows a strong impact of local environmental factors on bacterial community composition, with a marginal impact of spatial distance. Our results indicate that dispersal is not strongly limiting even at large spatial scales, and that mass effects do not have a strong impact on bacterial communities even in physically connected systems. We suggest that the fast population growth rates of bacteria facilitate efficient species sorting along environmental gradients in bacterial communities over a very broad range of dispersal rates.

The hyphal healing mechanism (HHM) has been shown to differ between Gigasporaceae and Glomeraceae. However, this process has not been considered under (severe) physical stress conditions. Scutellospora reticulata and Glomus clarum strains were cultured monoxenically. The impact of long distance separating cut extremities of hyphae and of multiple injuries within hyphae on the HHM was monitored. For long distances (>5000 microm) separating cut extremities, hyphae healing was observed in half the cases in S. reticulata and was absent in G. clarum. For multiple-injured hyphae, the HHM was always oriented towards the complete recovery of hyphae integrity in S. reticulata, while in G. clarum, the growing hyphal tips (GHTs) could indifferently reconnect cut sections, by-pass cut sections or develop into the environment. Hyphae behaviour under severe physical stress clearly differentiated S. reticulata from G. clarum, suggesting that both fungi have developed different strategies for colony growth to survive under adverse conditions.

Microinfusion of N-methyl-D-aspartate (NMDA) into apical dendrites of hippocampal CA1 pyramidal cells of urethane-anesthetized rats resulted in long lasting (20-30 min) induction of hippocampal synchrony at the field and cellular level. Power but not frequency of NMDA-induced theta was significantly greater than tail pinch-induced theta activity. This effect was antagonized by intrahippocampal infusion of AP5, but unaffected by i.v. atropine sulfate. During AP5 blockade tail pinch theta frequency and power were significantly reduced. Microinfusion of NMDA into the medial septum also resulted in long lasting induction of hippocampal theta field activity. Contrary to the results of hippocampal NMDA microinfusions, frequency but not power of NMDA-induced theta was significantly greater than tail pinch- induced theta activity. Microinfusion of AP5 into the medial septum significantly lowered power of tail pinch-induced theta but did not affect frequency. Wheel running behavior of rats induced by low levels of electrical stimulation of the posterior hypothalamic nucleus (PH) was completely abolished by microinfusion of AP5 into the medial septum, accompanied by a significant reduction in theta power and frequency. Wheel running and theta were maintained at control levels with high intensity PH stimulation. We propose that: (1) the glutamatergic septohippocampal projection represents a third pathway capable of generating hippocampal field and cellular synchrony, independent of that generated by the septohippocampal cholinergic and GABAergic projections, and (2) the septohippocampal glutamatergic projection serves to function as an interface between cholinergic and GABAergic modulated sensory processing Type 2 theta and movement related Type 1 theta.

The capacity of arbuscular mycorrhizal (AM) fungi to take up and translocate radiocaesium (Cs) to their host has been shown using the root-organ culture (ROC) system. However, the absence of photosynthetic tissues, lack of a normal root hormonal balance and incomplete source-sink relationships may bias the bidirectional transfer of elements at the symbiotic interface and complicate transport studies. Accordingly, we developed a novel culture system [i.e. the Arbuscular Mycorrhizal-Plant (AM-P) in vitro culture system], where AM fungi and an autotrophic host plant develop under strict in vitro conditions. With this system, we unambiguously demonstrated the capacity of AM fungi to transport Cs. The extraradical fungal hyphae took up 21.0% of the initial supply of 134Cs. Translocation to the plant represented 83.6% of the 134Cs taken up. Distribution of 134Cs in the host plant was 89.8% in the mycorrhizal roots and 10.2% in the shoot. These results confirm that AM fungi can take up, translocate and accumulate Cs. They further demonstrate unambiguously and for the first time that Cs can be transferred from AM fungi to host tissues. These results suggest a potential involvement of AM fungi in Cs biogeochemical cycle and in plant Cs accumulation.

An autotrophic culture system was developed for the in vitro mycorrhization of potato plantlets. Roots of micropropagated plantlets were associated to an arbuscular mycorrhizal fungus under in vitro conditions, while shoots developed under open air conditions. Several thousand spores, an extensive extraradical mycelium and an abundant root colonization were obtained. Spores were able to colonize new plantlets under the same conditions. These results support the capacity of the autotrophic culture system to continuously culture arbuscular mycorrhizal fungi and may serve as a powerful tool to investigate various aspects of the symbiosis for which a source-sink relationship and photosynthetic active tissues are necessary.

In natural host populations, parasitism is considered to be omnipresent and to play an important role in shaping host life history and population dynamics. Here, we study parasitism in natural populations of the zooplankton host Daphnia magna investigating their individual and population level effects during a 2-year field study. Our results revealed a rich and highly prevalent community of parasites, with eight endoparasite species (four microsporidia, one amoeba, two bacteria and one nematode) and six epibionts (belonging to five different taxa: Chlorophyta, Bacillariophyceae, Ciliata, Fungi and Rotifera). Several of the endoparasites were associated with a severe overall fecundity reduction of the hosts, while such effects were not seen for epibionts. In particular, infections by Pasteuria ramosa, White Fat Cell Disease and Flabelliforma magnivora were strongly associated with a reduction in overall D. magna fecundity. Across the sampling period, average population fecundity of D. magna was negatively associated with overall infection intensity and total endoparasite richness. Population density of D. magna was negatively correlated to overall endoparasite prevalence and positively correlated with epibiont richness. Finally, the reduction in host fecundity caused by different parasite species was negatively correlated to both parasite prevalence and the length of the time period during which the parasite persisted in the host population. Consistent with epidemiological models, these results indicate that parasite mediated host damages influence the population dynamics of both hosts and parasites.

The arbuscular mycorrhizal (AM) fungus Scutellospora reticulata (CNPAB11) was characterized using morphological, ontogenetic and molecular approaches. Spore ontogenesis was studied using Ri T-DNA transformed carrot roots and observations were compared with those published for eight other, pot-cultured, Scutellospora species. The sporogenesis of S. reticulata exhibited an unreported pattern of outer spore wall differentiation. In addition, Denaturing Gradient Gel Electrophoresis (DGGE), targeting the V9 region of the SSU nrDNA, was used to differentiate S. reticulata from 16 other Scutellospora species and results were confirmed by sequencing analysis. Phylogenetic analyses, using nearly full length SSU nrDNA sequences, grouped S. reticulata in a cluster together with S. cerradensis and S. heterogama, species that share similar spore wall organization and also possess ornamented external walls. PCR-DGGE and sequence analysis revealed intragenomic SSU nrDNA polymorphisms in four out of six Scutellospora species tested, and demonstrated that SSU nrDNA intragenomic polymorphism could be used as a marker to differentiate several closely related Scutellospora species.

Because mycorrhizal fungi are intimately associated with plant roots, their importance in radionuclide (RN) recycling and subsequent dispersion into the biosphere has received an increasing interest. Recently, the capacity of arbuscular mycorrhizal fungi to take up and translocate radiocaesium to their host was demonstrated. However, the relative contribution of these processes in comparison to the ones of roots remains unknown. Here, the respective contributions of the hyphae of a Glomus species and the transformed carrot (Daucus carota L.) roots on radiocaesium uptake and translocation were compared and quantified. We observed that radiocaesium uptake by hyphae was significantly lower as compared to that of the roots, while the opposite was noted for radiocaesium translocation/uptake ratio. We also observed that the intraradical fungal structures might induce a local accumulation of radiocaesium and concurrently reduce its translocation within mycorrhizal roots. We believe that intraradical fungal structures might induce the down-regulation of radiocaesium channels involved in the transport processes of radiocaesium towards the xylem.

The significance of anastomosis formation and the hyphal healing mechanism (HHM) for functionality and integrity of the arbuscular mycorrhizal (AM) fungal mycelial network remains poorly documented. Four Glomeraceae and three Gigasporaceae were cultured monoxenically. Anastomosis formation was assessed using the grid line method, while HHM was time-lapse monitored. In intact mycelial networks, the number of anastomosis per hyphal length was higher for Glomeraceae than for Gigasporaceae strains. Glomeraceae strains studied always formed anastomosis between different hyphae, whereas anastomosis in the Gigasporaceae more often concerned hyphal bridges within the same hyphae. In both families the HHM corresponded to a four-step process; first septum formation; second initiation of growing hyphal tips (GHTs); third GHT elongation, orientation and contact; and fourth GHT fusion and cytoplasmic/protoplasmic flux re-establishment. These four steps differentiated Glomeraceae from Gigasporaceae. The type and number of anastomosis per hyphal length, and the HHM differed considerably between Glomeraceae and Gigasporaceae families representing a supplementary character that distinguishes these two families and may be of significance in ecological studies of AM fungi.

This study aimed to quantify and compare 233U and 33P uptake and translocation by hyphae of the arbuscular mycorrhizal (AM) fungus Glomus intraradices in root organ culture conditions with transformed carrot (Daucus carota L.) roots as host. Mycorrhizal roots were grown in two-compartment Petri dishes to spatially separate a root compartment (RC) and a hyphal compartment (HC). The HC was labelled with 8.33 Bq 233U ml(-1) and 13.33 Bq 33P ml(-1). After 2 weeks contact between hyphae and the labelled solution, 233U and 33P activities were measured in the RC and in the HC. 233U and 33P were taken up by the extraradical AM mycelium grown in the HC and this uptake represented 4.4% and 16% of the initial isotope supply, respectively. The translocation into roots developing in the RC via hyphae accounted for 5.9% and 72% of the initial isotope supply, respectively. Thus, both uptake and translocation were much higher for 33P than for 233U. This suggests (1) the existence in hyphal tissues of efficient mechanisms limiting the uptake and translocation of non-essential elements such as U, and (2) that the hyphae have a higher sequestration than translocation function for U, and the converse for P.

The development of the extraradical mycelium and auxiliary cells and spore production of Scutellospora reticulata in association with Ri T-DNA transformed carrot roots was followed under root-organ culture conditions. Extraradical mycelium development followed classical lag-exponential-plateau phases, with an additional late decline phase in number of auxiliary cells. Spore production started in parallel with a critical extraradical mycelium biomass produced, continued long after root growth ceased and during the late decline in auxiliary cells number. Isolated auxiliary cells were shown to exhibit hyphal re-growth, but not root colonization, either in situ or in vitro. These results showed that root and extraradical mycelium development were intimately associated in a sequence where both grew together during active root growth, followed during root aging by a period in which only the fungus developed. Spore production appeared dependent on a critical extraradical mycelium biomass and on the re-allocation of resources from both the intraradical mycelium and the auxiliary cells via the hyphal network.

Mycelium development and architecture and spore production were studied in Scutellospora reticulata from single-spore isolates grown with Ri T-DNA transformed carrot root-organ culture in monoxenic system. Culture establishment, anastomosis occurrence and auxiliary cell development also were examined. Seventy percent of the pregerminated disinfected spores colonized the transformed carrot roots. After 8 mo, the average spore production was 56 (24-130) per 30 cm(3) of medium. Of the spores produced, 75% germinated and produced new generations in monoxenic culture. The mycelium network was formed by thick light-brown hyphae, which exhibit two major architecture patterns related to either root colonization or resource exploitation, and lower-order hyphae, bearing auxiliary cells, branched absorbing structures (BAS), hyphal swellings (HS) and forming anastomoses. BAS were formed abundantly in extramatrical mycelium and frequently had HS resembling vesicles, a feature not previously reported in the Gigasporaceae, to the best of our knowledge. Few anastomosis were observed within the mycelium and most often corresponded to a healing mechanism that form hypha bridges to reconnect broken hyphae or overcoming obstructed areas within a hypha. Numerous auxiliary cells were produced during culture development and their role was inferred.

The identification of phylogenetic clusters of bacteria that are common in freshwater has provided a basis for probe design to target important freshwater groups. We present a set of 16S ribosomal RNA gene-based oligonucleotide probes specific for 15 of these freshwater clusters. The probes were applied in reverse line blot hybridization, a simple method that enables the rapid screening of PCR products from many samples against an array of probes. The optimized assay was made stringent to discriminate at approximately the single-mismatch level. This made 10 of the probes highly specific, with at least two mismatches to the closest noncluster member in the global database. Screening of PCR products from bacterioplankton of 81 diverse lakes from Belgium, The Netherlands, Denmark, Sweden, and Norway showed that the respective probes were reactive against 5 to 100% of the lake samples. Positive reactivity of six highly specific probes showed that bacteria from actinobacterial clusters ACK-M1 and Sta2-30 and from verrucomicrobial cluster CLO-14 occurred in at least 90% of the investigated lakes. Furthermore, bacteria from alpha-proteobacterial cluster LD12 (closely related to the marine SAR11 cluster), beta-proteobacterial cluster LD28 and cyanobacterial cluster Synechococcus 6b occurred in more than 70% of the lakes. Reverse line blot hybridization is a new tool in microbial ecology that will facilitate research on distribution and habitat specificity of target species at relatively low costs.

The interaction between Glomus intraradices and Pratylenchus coffeae on transformed carrot roots was studied in root organ culture. G. intraradices provided the roots with increased protection against P. coffeae by suppressing nematode reproduction in the roots. The internal and external mycorrhizal development was not influenced by the presence of the nematodes.

Radiocaesium enters the food chain when plants absorb it from soil, in a process that is strongly dependent on soil properties and plant and microbial species. Among the microbial species, arbuscular mycorrhizal (AM) fungi are obligate symbionts that colonize the root cortex of many plants and develop an extraradical mycelial (ERM) network that ramifies in the soil. Despite the well-known involvement of this ERM network in mineral nutrition and uptake of some heavy metals, only limited data are available on its role in radiocaesium transport in plants. We used root-organ culture to demonstrate that the ERM of the AM fungus Glomus lamellosum can take up, possibly accumulate and unambiguously translocate radiocaesium from a 137Cs-labelled synthetic root-free compartment to a root compartment and within the roots. The accumulation of 137Cs by hyphae in the root-free compartment may be explained by sequestration in the hyphae or by a bottleneck effect resulting from a limited number of hyphae crossing the partition between the two compartments. Uptake and translocation resulted from the incorporation of 137Cs into the fungal hyphae, as no 137Cs was detected in mycorrhizal roots treated with formaldehyde. The importance of the translocation process was indicated by the correlation between 137Cs measured in the roots and the total hyphal length connecting the roots with the labelled compartment. 137Cs may be translocated via a tubular vacuolar system or by cytoplasmic streaming per se.

•  Uranium (U) uptake and translocation by the arbuscular mycorrhizal (AM) fungus Glomus intraradices were studied under root-organ culture conditions with Agrobacterium rhizogenes -transformed carrot ( Daucus carota ) roots as host. •  Two-compartment Petri plates were used to spatially separate a root compartment (RC) and a hyphal compartment (HC); root growth was restricted to the RC while extraradical hyphae grew in both RC and HC. The HC was labelled with 0.1 µM 233 U at different pH conditions. At the end of the experiment, U was measured in the RC and in the HC. •  The U absorption by the AM fungus was observed. It included; U uptake by the mycelium developing in the HC, and U translocation from the HC to the RC. The magnitude of this uptake and translocation was highly influenced by the pH of the growth medium, while translocation was highly correlated with the number of hyphae crossing the partition separating the two compartments. •  These results are the first to show that an AM fungus can take up and translocate U towards roots.

A strain of Acaulospora rehmii was, for the first time, successfully grown in vitro on Ri T-DNA transformed carrot roots allowing the in situ observation of Acaulospora spore development and of extraradical thin-walled hyphal swellings. The sporogenous hypha developed intercalarly along thin-walled coenocytic hyphae. The distal part of the sporogenous hypha swelled slightly as a sporiferous saccule primordium followed by the differentiation of a lateral spore primordium along the neck of the sporogenous hypha. Both structures matured simultaneously, and the sporiferous saccule began to collapse after spore maturation and complete differentiation of the spore wall. Several of the in situ observations on in vitro differentiated A. rehmii spores are concordant with previous ontogenic studies done on other Acaulospora species obtained from in vivo cultures. New and original observations on the early developmental stages of sporiferous saccules and spores and on the occurrence of small diameter intercalary hyphal swellings provide additional elements in the study of Acaulospora sporulation process and life cycle.

• A new method is described for monitoring hyphal 32 P transport in compartmented, monoxenic mycorrhizal root cultures. Nondestructive time-course measurements of P transport in hyphae were obtained by capturing digital autoradiograms on P-imaging screens, and comparing with growth observed by optical scanning. 32 P distribution measured by densitometry on the day of harvest closely agreed with values obtained by liquid scintillation counting after destructive harvest. • Virtually all labeled PO 4 was absorbed by arbuscular mycorrhizal (AM) hyphae, but transfer to the roots appeared to be incomplete. P transport was not unidirectional towards the roots, as 32 P was also transported from the root compartment to the hyphal compartment. Net P flux rates were calculated for hyphae crossing between compartments, taking bidirectional flow into account. • Amounts of transported P were poorly correlated with extra-radical hyphal length and root d. wt, but highly correlated with the number of hyphae crossing the barrier separating the two compartments. Such correlations were highest when only hyphae with detectable protoplasmic streaming were considered. • The method was tested using radiolabeled P sources, H 2 PO 4 - and cytidine triphosphate (CTP), and the AM fungi, Glomus intraradices and G. proliferum. Fungal transport of 32 P from CTP was much slower than from PO 4 for both fungi.

Creation of a transabdominal transdiaphragmatic pericardial window for life-threatening recurrent pericardial effusion has proved to be a safe minimally invasive technique. By inducing adequate pericardial sac decompression while avoiding single-lung ventilation and thoracic drainage in severely ill patients, it provides anatomopathologic diagnosis and can direct further therapeutic measures. The transabdominal approach improves postoperative recovery dramatically by limiting postoperative pain and prevents sometimes invalidating intercostal neuralgia. Transabdominal pericardial sac fenestration should be part of the armamentarium used by every minimally invasive surgeon.

A study was conducted to quantify the ability of entrapped, monoxenically produced spores of an arbuscular mycorrhizal fungus to germinate and reproduce the fungal life cycle after cryopreservation. No germination was obtained after incubation of entrapped spores in glycerol and mannitol and subsequent cryopreservation at -70 °C, regardless of the concentration of cryoprotectants and duration of incubation. Incubation for 1 d in 0.5 M sucrose, and for 1 and 2 d in 0.5 M trehalose, led to spore germination after cryopreservation at -70 °C. Lower cryopreservation temperatures were tested with entrapped spores incubated for 1 d in 0.5 M trehalose. The highest germination rate, estimated by the percentage of potentially infective beads (%PIB), was obtained at -100 °C. A %PIB of 95% (water agar medium) to 100% (Strullu-Romand medium) was obtained at this temperature. Thereafter, %PIB rapidly decreased at -140 and -180 °C. Heavy sporulation and high internal root colonization were obtained after re-association of the entrapped spores, incubated for 1 d in 0.5 M trehalose and subsequently cryopreserved at -100 °C, with transformed carrot roots. This demonstrates the ability of entrapped spores to reproduce the fungal life cycle following cold treatment.

Lingual thyroid is the most frequent benign mass found at the junction of the anterior two-thirds and posterior one-third of the tongue. MR has become the best non-invasive technique to make the diagnosis because it allows multiplanar imaging and provides the best soft tissue definition. Aberrant primitive vascular supply is often present and therefore angiography remains necessary because precise knowledge of the vascular supply is mandatory prior to embolisation, ligation, or operation.