Photosynthetic apparatus performance in function of the cytokinins used during the in vitro multiplication of <Emphasis Type="Italic">Aechmea blanchetiana</Emphasis> (Bromeliaceae)

During the in vitro multiplication phase, the employment of cytokinins may be necessary to induce side shoots of many plant species. However, the mechanism by which cytokinins influence the physiology of plants in vitro is not well understood. Therefore, the objective of this study was to assess the influence of two cytokinins in function of concentration on the o photosynthetic apparatus performance and the stomatal functionality of Aechmea blanchetiana during in vitro multiplication. Plants previously established in vitro were transferred to MS culture media supplemented with 6-benzylaminopurine (BAP) or 6-furfurylaminopurine (kinetin—KIN) at concentration of 0, 5, 10, 15 or 20 µM. After 60 days of exposure to the plant growth regulators, the multiplication rate, photosynthetic apparatus performance and stomatal functionality were assessed. The use of KIN did not induce the formation of microshoots. On the other hand, the shoot number increased with rising BAP concentration. There was a reduction of the maximum fluorescence (F_m) and maximum quantum yield (φP₀) as a function of concentration of cytokinins. The most pronounced decrease was observed in the microshoots grown with KIN. The increase in concentration of cytokinins induced greater absorption flux (ABS/RC), trapping flux (TR₀/RC) and dissipation flux (DI₀/RC) of energy per reaction center. The stomatal functionality declined with rising cytokinin concentration. The use of KIN is not recommended for in vitro multiplication of this species. The use of BAP at low concentrations assures a multiplication rate with lower degree of disorders in the photosynthetic apparatus of the formed microshoots.     

Genetic Control of Spontaneous Arthritis in a Four-Way Advanced Intercross Line

Identifying the genetic basis of complex diseases, such as rheumatoid arthritis, remains a challenge that requires experimental models to reduce the genetic and environmental variability. Numerous loci for arthritis have been identified in induced animal models; however, few spontaneous models have been genetically studied. Therefore, we generated a four-way advanced intercross line (AIL) from four inbred strains, including BXD2/TyJ which spontaneously develops autoimmune arthritis. A genome-wide scan for spontaneous arthritis was performed in a cohort of 366 mice of the fourth generation (G4) of this cross. Five loci contributing to clinical phenotypes were identified in chromosomes 3, 7, 13, 18, and X. Three of the loci found in this study, confirm previously identified loci; whereas two of them are novel loci. Interesting candidate genes for the loci are highlighted. This study provides a genetic overview of spontaneous arthritis in mice and aids to solve the genetic etiology of rheumatoid arthritis and to gain a better understanding of the disease.     

A new quantitative in vitro microculture method for Giardia duodenalis trophozoites

A reliable, rapid and low-cost method for drug sensitivity determination of Giardia duodenalis trophozoites (WB-strain) was developed in a 96-well plate. Using a standard inoculum of 5 x 10(4) trophozoites per well (300 microl), good growth was obtained after sealing the plate with an air-tight adhesive tape and incubation at 37 degrees C for 72 h in modified TYI-S-33 medium. Viable burdens were quantified using the formazan dyes MTT (100 microg/well) and XTT (20 microg/well) and the fluorescent substrate resazurin (2.5 microg/well). Prior removal of the culture medium is required since it causes spontaneous reduction of the substrate. Resazurin proved to be far superior to MTT and XTT with a level of sensitivity of about 3 x 10(4) trophozoites. Inhibitory concentrations (IC(50)) of several anti-giardial reference drugs were within the range of published values: metronidazole 2.25 microM, tinidazole 1.75 microM, albendazole 0.10 microM, furazolidone 2.00 microM and quinacrine 0.32 microM. The broad-spectrum antibiotics chloramphenicol, rifampicin, penicillin G+streptomycin and gentamycin were devoid of any inhibitory activity and are considered suitable for decontamination during excystation experiments.     

Anatomical,physiological, and biochemical modulations of silicon in Aechmea blanchetiana (Bromeliaceae) cultivated in vitro in response to cadmium

Cadmium (Cd) has no known biological role in plants but shows high toxicity. A viable alternative to alleviate the deleterious effects of plants under heavy metal stress is with the use of silicon (Si). The objective was to investigate the anatomical, physiological, and biochemical modulations of Aechmea blanchetiana exposed to Cd in vitro and the Cd and Si co-exposure. Plants previously established under in vitro culture conditions were transferred to MS culture medium with 0 or 14 µM Si and solidified with agar. After 30 days of growth, a stationary liquid MS medium containing increasing concentrations of Cd (0, 50, 100 or 200 μM) was added to the containers, forming a biphasic medium. After 45 days, anatomical and physiological analyses were performed. Plants cultivated with 14 µM Si showed a thinner exodermis, a decrease in the Chl a/b ratio and a higher total Chl/Car ratio. The positive L- and K-bands were verified at all applied Cd concentrations. Cd induced damage to the oxygen-evolving complex (W_K) and altered the quantum yield of non-regulated energy dissipation (ΦNO). In the presence of Si there was an increase in the photochemical activity of photosystem II and electron transport, even when the plants were exposed to Cd. The plants were able to withstand exposure to Cd, although exhibiting physiological disturbances. The anatomical, physiological, and biochemical responses induced by Si were effective in easing the stress of A. blanchetiana plants grown in vitro with Cd.

     

Phaeodactylum tricornutum biomass in microdiets enhances Senegalese sole (Solea senegalensis) larval growth performance during weaning

Journal of Applied Phycology - Microalgae are one of the most promising groups of functional ingredients for inclusion in microdiets for Senegalese sole (Solea senegalensis) larvae, supplying...     

The alliance for cellular signaling plasmid collection: a flexible resource for protein localization studies and signaling pathway analysis

Cellular responses to inputs that vary both temporally and spatially are determined by complex relationships between the components of cell signaling networks. Analysis of these relationships requires access to a wide range of experimental reagents and techniques, including the ability to express the protein components of the model cells in a variety of contexts. As part of the Alliance for Cellular Signaling, we developed a robust method for cloning large numbers of signaling ORFs into Gateway entry vectors, and we created a wide range of compatible expression platforms for proteomics applications. To date, we have generated over 3000 plasmids that are available to the scientific community via the American Type Culture Collection. We have established a website at www.signaling-gateway.org/data/plasmid/ that allows users to browse, search, and blast Alliance for Cellular Signaling plasmids. The collection primarily contains murine signaling ORFs with an emphasis on kinases and G protein signaling genes. Here we describe the cloning, databasing, and application of this proteomics resource for large scale subcellular localization screens in mammalian cell lines.     

Effect of temperature,pH and ionic strength on hydroxyapatite stabilised Pickering emulsions produced in batch and continuous mode

Oil-in-water (O/W) Pickering emulsions are attracting attention as carriers of lipophilic active compounds with clear advantages over traditional systems. Having in view their effective use it is important to study their stability against environmental stresses impacting manufacture, storage, and application conditions. In this work, hydroxyapatite nanoparticles (n-HAp) Pickering emulsions produced in continuous mode using a mesostructured reactor (average size?~?7, 11 and 18 µm) and in batch mode using a rotor–stator device (average size?~?18 µm) were studied concerning their behaviour at different temperatures (5–90 ºC), pH (2–10) and ionic strength (0–500 mM), conditions with relevance for food applications. Droplet size, morphology, and zeta-potential were analysed after 1 and 7 days under storage. In general, and despite the droplet size, the n-HAp Pickering emulsions were stable within the tested ionic strength range, at relatively high pH environments (6–10), and at temperatures up to 70 ºC. Pickering emulsions undergo complete phase separation at very low pH (2) due to n-HAp particle's disruption. A clear tendency to aggregation and coalescence was observed for high temperatures (70–90 ºC). Results indicate no significant differences related to the used production method. From an industrial perspective, this work also corroborates that the scale-up to a continuous process using a mesostructured reactor, NETmix, from a batch laboratorial process is feasible without impacting stability.

Graphical abstract

     

Novel 3-hydroxy-4-pyridinonato oxidovanadium(IV) complexes to investigate structure/activity relationships

A previous evaluation of the insulin-like activity of three 3-hydroxy-4-pyridinonato oxidovanadium(IV) complexes raised questions about structure/activity relationships, namely the influence of the hydrophilic/lipophilic balance of the complex and the capacity of the ligand to stabilize the +4 oxidation state of vanadium ion, on achieving an positive effect. To address these questions, we synthesized six new oxidovanadium(IV) complexes with variable hydrophilic/lipophilic balance, obtained by introducing different substituents on the nitrogen atom, and used two 3-hydroxy-4-pyrones as starting reagents to provide methyl and ethyl groups in the ortho position of the ring. For the new and previously reported complexes, we studied the oxidation-reduction properties and insulin-like activity in terms of inhibitory effect on Free fatty acid (FFA) release in isolated rat adipocytes. The results obtained show that only one of the complexes, Bis(3-hydroxy-1(H)-2-methyl-4-pyridonato)oxidovanadium(IV), VO(mpp)₂, exhibits a significantly greater capacity to inhibit FFA release than VOSO₄ and consequently is worthy to be considered for further studies. The establishment of structure activity relationships was not attainable but this study brings new information about the influence of some properties of the compounds on the achievement of an insulin-like effect. The results reveal that: (i) the oxidation-reduction cycles of the complexes are identical; (ii) the presence of more lipophilic substituents on the nitrogen atom does not enhance insulin-like properties; (iii) a high solubility in water proved to be not sufficient for a positive activity in inhibiting FFA release; (iv) a small molecular size may be an important property for reaching the right targets.     

Complete Staining of Nerve Fiber and Myoneural Junctions with Acetylthiocholine and Silver

We describe a combined stain for simultaneous demonstration of the preterminal axons and cholinesterase activity at myoneural junctions of mammalian muscles. This technique employs acetylthiocholine iodide as the substrate for cholinesterase activity and silver nitrate impregnation of preterminal axons. The procedure is rapid, simple and Uses fresh muscles. Intramuscular nerves, preterminal axons and myoneural junctions are stained simultaneously brown or black with minimal background staining of connective tissue and muscle fibers.