First cryo-scanning electron microscopy images and X-ray microanalyses of mucoromycotinian fine root endophytes in vascular plants

Aims. Arbuscule-producing fine root endophytes (FRE) (previously incorrectly Glomus tenue) were recently placed within subphylum Mucoromycotina; the first report of arbuscules outside subphylum Glomeromycotina. Here, we aimed to estimate nutrient concentrations in plant and fungal structures of FRE and to test the utility of cryo-scanning electron microscopy (cryoSEM) for studying these fungi. Methods. To do so, we used replicated cryoSEM and X-ray microanalysis of heavily colonized roots of Trifolium subterraneum. Results. Intercellular hyphae and hyphae in developed arbuscules were consistently very thin; 1.35 ± 0.03 µm and 0.99 ± 0.03 µm in diameter, respectively (mean ± SE). Several intercellular hyphae were often adjacent to each other forming ‘hyphal ropes’. Developed arbuscules showed higher phosphorus concentrations than senesced arbuscules and non-colonized structures. Senesced arbuscules showed greatly elevated concentrations of calcium and magnesium. Conclusions. While uniformly thin hyphae and hyphal ropes are distinct features of FRE, the morphology of fully developed arbuscules, elevated phosphorus in fungal structures, and accumulation of calcium with loss of structural integrity in senesced arbuscules are similar to glomeromycotinian fungi. Thus, we provide evidence that FRE may respond to similar host-plant signals or that the host plant may employ a similar mechanism of association with FRE and AMF

Ecto- and arbuscular mycorrhizal symbiosis can induce tolerance to toxic pulses of phosphorus in jarrah (Eucalyptus marginata) seedlings

In common with many plants native to low P soils, jarrah (Eucalyptus marginata) develops toxicity symptoms upon exposure to elevated phosphorus (P). Jarrah plants can establish arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) associations, along with a non-colonizing symbiosis described recently. AM colonization is known to influence the pattern of expression of genes required for P uptake of host plants and our aim was to investigate this phenomenon in relation to P sensitivity. Therefore, we examined the effect on hosts of the presence of AM and ECM fungi in combination with toxic pulses of P and assessed possible correlations between the induced tolerance and the shoot P concentration. The P transport dynamics of AM (Rhizophagus irregularis and Scutellospora calospora), ECM (Scleroderma sp.), non-colonizing symbiosis (Austroboletus occidentalis), dual mycorrhizal (R. irregularis and Scleroderma sp.), and non-mycorrhizal (NM) seedlings were monitored following two pulses of P. The ECM and A. occidentalis associations significantly enhanced the shoot P content of jarrah plants growing under P-deficient conditions. In addition, S. calospora, A. occidentalis, and Scleroderma sp. all stimulated plant growth significantly. All inoculated plants had significantly lower phytotoxicity symptoms compared to NM controls 7 days after addition of an elevated P dose (30 mg P kg−1 soil). Following exposure to toxicity-inducing levels of P, the shoot P concentration was significantly lower in R. irregularis-inoculated and dually inoculated plants compared to NM controls. Although all inoculated plants had reduced toxicity symptoms and there was a positive linear relationship between rank and shoot P concentration, the protective effect was not necessarily explained by the type of fungal association or the extent of mycorrhizal colonization

Recent publications from the Alzheimer's Disease Neuroimaging Initiative: Reviewing progress toward improved AD clinical trials

INTRODUCTION: The Alzheimer's Disease Neuroimaging Initiative (ADNI) has continued development and standardization of methodologies for biomarkers and has provided an increased depth and breadth of data available to qualified researchers. This review summarizes the over 400 publications using ADNI data during 2014 and 2015. METHODS: We used standard searches to find publications using ADNI data. RESULTS: (1) Structural and functional changes, including subtle changes to hippocampal shape and texture, atrophy in areas outside of hippocampus, and disruption to functional networks, are detectable in presymptomatic subjects before hippocampal atrophy; (2) In subjects with abnormal β-amyloid deposition (Aβ+), biomarkers become abnormal in the order predicted by the amyloid cascade hypothesis; (3) Cognitive decline is more closely linked to tau than Aβ deposition; (4) Cerebrovascular risk factors may interact with Aβ to increase white-matter (WM) abnormalities which may accelerate Alzheimer's disease (AD) progression in conjunction with tau abnormalities; (5) Different patterns of atrophy are associated with impairment of memory and executive function and may underlie psychiatric symptoms; (6) Structural, functional, and metabolic network connectivities are disrupted as AD progresses. Models of prion-like spreading of Aβ pathology along WM tracts predict known patterns of cortical Aβ deposition and declines in glucose metabolism; (7) New AD risk and protective gene loci have been identified using biologically informed approaches; (8) Cognitively normal and mild cognitive impairment (MCI) subjects are heterogeneous and include groups typified not only by "classic" AD pathology but also by normal biomarkers, accelerated decline, and suspected non-Alzheimer's pathology; (9) Selection of subjects at risk of imminent decline on the basis of one or more pathologies improves the power of clinical trials; (10) Sensitivity of cognitive outcome measures to early changes in cognition has been improved and surrogate outcome measures using longitudinal structural magnetic resonance imaging may further reduce clinical trial cost and duration; (11) Advances in machine learning techniques such as neural networks have improved diagnostic and prognostic accuracy especially in challenges involving MCI subjects; and (12) Network connectivity measures and genetic variants show promise in multimodal classification and some classifiers using single modalities are rivaling multimodal classifiers. DISCUSSION: Taken together, these studies fundamentally deepen our understanding of AD progression and its underlying genetic basis, which in turn informs and improves clinical trial desig

The node of Ranvier in CNS pathology.

Healthy nodes of Ranvier are crucial for action potential propagation along myelinated axons, both in the central and in the peripheral nervous system. Surprisingly, the node of Ranvier has often been neglected when describing CNS disorders, with most pathologies classified simply as being due to neuronal defects in the grey matter or due to oligodendrocyte damage in the white matter. However, recent studies have highlighted changes that occur in pathological conditions at the node of Ranvier, and at the associated paranodal and juxtaparanodal regions where neurons and myelinating glial cells interact. Lengthening of the node of Ranvier, failure of the electrically resistive seal between the myelin and the axon at the paranode, and retraction of myelin to expose voltage-gated K(+) channels in the juxtaparanode, may contribute to altering the function of myelinated axons in a wide range of diseases, including stroke, spinal cord injury and multiple sclerosis. Here, we review the principles by which the node of Ranvier operates and its molecular structure, and thus explain how defects at the node and paranode contribute to neurological disorders

Gas channels and chimneys prediction using artificial neural networks and multi-seismic attributes, offshore West Nile Delta, Egypt

Machine learning techniques combined with multi-seismic attributes and well logs datasets have been successfully used in reducing the risk of drilling operations and petroleum exploration by providing precise petrophysical and seismic information extracted from the hydrocarbon reservoir rocks. For this purpose, Artificial Neural Networks (ANNs) work as a multi-channel processing system with a high degree of interconnection to classify various faces and predict the reservoir properties through the seismic profile by involving multi-seismic attributes and optionally well logs to the inputs. The main aim of this study is to use both supervised and unsupervised neural networks for the first time in the West Delta Deep Marine (WDDM) concession to identify the spatial dimensions of the gas-bearing channels and the detection of gas chimneys across the seismic profiles. We use back-error propagation algorithms of the Multilayer Perceptron (MLP) and self-organizing Unsupervised Vector Quantizer (UVQ) as supervised and unsupervised neural network methods, respectively, to detect the gas zones and channels, and to classify the gas chimneys and non-gas chimneys zones, as well as classification of the seismic reflections and lithologies. The output acquires a detailed analysis of the distribution pattern of gas channels and accurate information to image the gas chimneys. In the current study, the approach adopted is beneficial to image the gas chimneys and channels in different basins in any region of the world with similar geological settings

The detection of deep seafloor pockmarks, gas chimneys, and associated features with seafloor seeps using seismic attributes in the West offshore Nile Delta, Egypt

The West Delta Deep Marine (WDDM) concession is one of the abundant natural gas resources in the world characterised by the presence of several active gas chimneys conduit feeding pockmarks. The detection of shallow gas accumulations has been gaining importance in hazard assessments before and during offshore drilling operations, whereas there is no way to estimate the exact pressure of the gas content in sediment to expect the potential gas hazards before and during the offshore installations, operations, and drilling. Monitoring of the gas chimneys and pockmarks plays an important role as an early warning for the oil industry to more focus on this kind of activities which may represent a catastrophic event in the future for the offshore installations at the WDDM region. Moreover, the “‘return period” of the pockmark activities is a region-dependence parameter according to the continuity of the gas supply and stability of the seepage pathway. However, in this study, the identification of the direct and indirect evidence of the shallow gas presence and migration pathways to the seafloor is achieved by extracting various-chosen seismic attributes, such as Root Mean Square, envelope, energy, the cosine of the instantaneous phase, variance, and chaos attributes. These attributes improve the imaging of several seismic evidence such as bright anomalies, enhanced reflectors, gas chimneys, and associated seabed features formed by the migration of the fluids from deep reservoirs through gas chimneys up to the seafloor. The presented profiles clearly show that gas chimneys and pockmarks combined with other associated features represent common features of the WDDM concession that can severely impact during and after offshore drilling operations in the aspects of safety, environment, and cost

Globular structures in roots accumulate phosphorus to extremely high concentrations following phosphorus addition

Crops with improved uptake of fertilizer phosphorus (P) would reduce P losses and confer environmental benefits. We examined how P-sufficient 6-week-old soil-grown Trifolium subterraneum plants, and 2-week-old seedlings in solution culture, accumulated P in roots after inorganic P (Pi) addition. In contrast to our expectation that vacuoles would accumulate excess P, after 7 days, X-ray microanalysis showed that vacuolar [P] remained low (3,000 mmol kg-1 ), potassium, magnesium, and sodium. Similar structures were evident in seedlings, both before and after P addition, with their [P] increasing threefold after P addition. Nuclear magnetic resonance (NMR) spectroscopy showed seedling roots accumulated Pi following P addition, and transmission electron microscopy (TEM) revealed large plastids. For seedlings, we demonstrated that roots differentially expressed genes after P addition using RNAseq mapped to the T. subterraneum reference genome assembly and transcriptome profiles. Among the most up-regulated genes after 4 hr was TSub_g9430.t1, which is similar to plastid envelope Pi transporters (PHT4;1, PHT4;4): expression of vacuolar Pi-transporter homologs did not change. We suggest that subcellular P accumulation in globular structures, which may include plastids, aids cytosolic Pi homeostasis under high-P availability.Megan H. Ryan, Parwinder Kaur, Nazanin K. Nazeri, Peta L. Clode, Gabriel Keeble‐Gagnèr