Effects of calcium deficiency on Coffea arabica. Nutrient changes and correlation of calcium levels with some photosynthetic parameters

Calcium deficiency was induced in hydroponically grown 1.5-years-old coffee plants with 12–14 pairs of leaves. Calcium was given in the form of Ca(NO₃)₂: 5, 2.5, 0.1, 0.01 and 0 mM. After 71 days of Ca-treatment root and shoot as well as total biomass were decreased by severe Ca-deficiency. However, a stronger decrease was observed for shoot growth as revealed by the increase in the root/shoot ratio. New leaves were affected showing decreases in the total leaf area and in Leaf Area Duration (LAD). After 91 days of deficiency, leaf protein concentration decreased (by about 45%) in the top leaves while nitrate reductase activity (NRA) and NO₃ content showed no significant changes. Total nitrogen and mineral concentrations (P, K, Ca, Mg and Na) were also determined in leaves and roots. With the decrease in calcium concentration in Ca-deficiency conditions, we observed concomitant increases in the concentrations of K⁺, Mg²⁺ and Na⁺ in leaves (maximal changes of 32% for K⁺, 96% for Mg²⁺ and 438% for Na⁺) and in roots (108% for K⁺, 86% for Mg²⁺ and 38% for Na⁺). Accordingly, the ratio between elements changed, including the ratio N/P, showing a non-equilibrium in the balance of nutrients. Significant correlations were obtained between Ca²⁺ concentration and some photosynthetic parameters. Ca-deficiency conditions would increase the loss of energy as expressed by the rise in a_E and decrease the photochemical efficiency, which confirms the importance of this element in the stabilization of chlorophyll and in the maintenance of good photochemical efficiency at PS II level.Abbreviations Chl Chlorophyll - Fv/Fm ratio of variable to maximal fluorescence - LAD leaf area duration - LHC II light harvesting complex of PS II - NRA nitrate reductase activity - PC photosynthetic capacity - PS II photosystem II - P₆₈₀ reaction center of PS II - q_N non-photochemical quenching - q_E high-energy dependent quenching - q_p photochemical quenching - SLA specific leaf area     

Exploiting aberrant mRNA expression in autism for gene discovery and diagnosis

Autism spectrum disorder (ASD) is characterized by substantial phenotypic and genetic heterogeneity, which greatly complicates the identification of genetic factors that contribute to the disease. Study designs have mainly focused on group differences between cases and controls. The problem is that, by their nature, group difference-based methods (e.g., differential expression analysis) blur or collapse the heterogeneity within groups. By ignoring genes with variable within-group expression, an important axis of genetic heterogeneity contributing to expression variability among affected individuals has been overlooked. To this end, we develop a new gene expression analysis method—aberrant gene expression analysis, based on the multivariate distance commonly used for outlier detection. Our method detects the discrepancies in gene expression dispersion between groups and identifies genes with significantly different expression variability. Using this new method, we re-visited RNA sequencing data generated from post-mortem brain tissues of 47 ASD and 57 control samples. We identified 54 functional gene sets whose expression dispersion in ASD samples is more pronounced than that in controls, as well as 76 co-expression modules present in controls but absent in ASD samples due to ASD-specific aberrant gene expression. We also exploited aberrantly expressed genes as biomarkers for ASD diagnosis. With a whole blood expression data set, we identified three aberrantly expressed gene sets whose expression levels serve as discriminating variables achieving >70 % classification accuracy. In summary, our method represents a novel discovery and diagnostic strategy for ASD. Our findings may help open an expression variability-centered research avenue for other genetically heterogeneous disorders.     

Beiträge zur Flora von Wien

Ohne ZusammenfassungVielleicht ist einer oder der andere von den durch mich gebrachten Standorten schon bekannt. Da ich aber dieselben in der mir zugängigen Literatur noch nicht erwähnt fand, glaube ich im Interesse der Wissenschaft zu handeln, wenn ich diese, wenn auch ganz unbedeutenden Erfahrungen des Herrn Fr. v. Höhnel und meiner Person an dieser Stelle veröffentliche.     

Histochimie du Pancreas du Chat Avec Discussion du Tissu Langerhansien Endocrine

Résumé Des recherches histologiques et histochimiques sont faites sur le pancréas du chat avec discussion surtout au sujet du tissu endocrine. Quelques particularités sont signalées: la richesse en îlots ganglionnaires, en corpuscules de Pacini et en complexes neuro-insulaires, aussi bien que l'existence dans la partie apicale de l'épithélium des canaux excréteurs de granulations paraldéhyde positives. En principe l'histoenzymologie du pancréas du chat est semblable à celle des autres mammifères mais ne lui est pas toujours identique. Certaines considérations sont faites sur le rôle probable des enzymes étudiées et du Zn dans la cytophysiologie insulaire.

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Summary Morphological and histochemical investigations on the pancreas of cat have been carried out and discussion on the question of the endocrine tissue. Some particularities are marked down: abundance of ganglion islets, of corpuscules of Pacini and neuro-insular complexes, as well as existence of positive paraldehyde granulations in the top portion of the epithelium of the excretory ducts. In general the histoenzymology of the pancreas of the cat is similar to other mammals, but is not always identical. Some considerations on the probable role of the enzymes investigated and on the zinc in the insular cytophysiology are made.

     

Factors influencing skin autofluorescence of patients with peritoneal dialysis

Skin autofluorescence (SAF) measurement is a simple, noninvasive method to assess tissue advanced glycation end products (AGE). In patients with end-stage renal disease and in those on hemodialysis AGE production is increased. Less is known about those treated with peritoneal dialysis (PD). In this study we tested if SAF is influenced by clinical and treatment characteristics in PD patients.This cross-sectional study included 198 PD patients (of those, 128 were on traditional glucose-based solutions and 70 patients were partially switched to icodextrin-based PD). SAF measurements were done with a specific AGE Reader device. The impact of patients' age, gender, current diabetes, duration of PD, cumulative glucose exposure, body mass index, smoking habits and use of icodextrin on SAF values were tested with multiple regression analysis.Our analysis revealed that patients' age, current diabetes and icodextrin use significantly increase patients' SAF values (p = 0.015, 0.012, 0.005, respectively). AGE exposure of PD patients with diabetes and on icodextrin solution is increased. Further investigation is required whether this finding is due to the icodextrin itself or for a still unspecified clinical characteristic of PD population treated with icodextrin.     

Cardosins improve neuronal regeneration after cell disruption: a comparative expression study

The establishment of primary cell cultures is invaluable for studying cell and molecular biological questions. Although primary cell cultures more closely resemble and function like in the native environment, during the culture establishment the cells undergo several changes including the damage sustained during their removal from original tissue. The resultant cells have to rebalance the expression of their processing molecules to ascertain matrix signalling that ensure cell adaptation and consequent proliferation. Hence, we used cardosin, a novel plant enzyme for tissue disaggregation, for isolating and culturing neuronal cells from embryonic rats. The present investigation reports the molecular events, mainly related with matrix metalloproteinases (MMPs)/tissue inhibitor of metalloproteinase (TIMPs) expression, which could substantiate the superior neurite outgrowth and dendritic extension previously described. It was observed that 24 h after primary culture establishment, MMP-2 and MMP-9 messenger RNA (mRNA) are significantly upregulated, while the expression of TIMP-1 and TIMP-2 is unaltered. Regarding the role of laminin in neuronal pathfinding, it was found that the use of anti-laminin antibody and arginine–glycine–aspartate (RGD) peptide exerted inhibitory effects on neurite outgrowth after mechanical lesion where the expression of MMP-9 and TIMP-1 is upregulated under non-permissive conditions in response to mechanical injury.     

A Multiscale Red Blood Cell Model with Accurate Mechanics, Rheology, and Dynamics

Red blood cells (RBCs) have highly deformable viscoelastic membranes exhibiting complex rheological response and rich hydrodynamic behavior governed by special elastic and bending properties and by the external/internal fluid and membrane viscosities. We present a multiscale RBC model that is able to predict RBC mechanics, rheology, and dynamics in agreement with experiments. Based on an analytic theory, the modeled membrane properties can be uniquely related to the experimentally established RBC macroscopic properties without any adjustment of parameters. The RBC linear and nonlinear elastic deformations match those obtained in optical-tweezers experiments. The rheological properties of the membrane are compared with those obtained in optical magnetic twisting cytometry, membrane thermal fluctuations, and creep followed by cell recovery. The dynamics of RBCs in shear and Poiseuille flows is tested against experiments and theoretical predictions, and the applicability of the latter is discussed. Our findings clearly indicate that a purely elastic model for the membrane cannot accurately represent the RBC's rheological properties and its dynamics, and therefore accurate modeling of a viscoelastic membrane is necessary.