Micromechanics of root development in soil

International audienc

Dependence of cancer cell adhesion kinetics on integrin ligand surface density measured by a high-throughput label-free resonant waveguide grating biosensor

A novel high-throughput label-free resonant waveguide grating (RWG) imager biosensor, the Epic® BenchTop (BT), was utilized to determine the dependence of cell spreading kinetics on the average surface density (vRGD) of integrin ligand RGD-motifs. vRGD was tuned over four orders of magnitude by co-adsorbing the biologically inactive PLL-g-PEG and the RGD-functionalized PLL-g-PEG-RGD synthetic copolymers from their mixed solutions onto the sensor surface. Using highly adherent human cervical tumor (HeLa) cells as a model system, cell adhesion kinetic data of unprecedented quality were obtained. Spreading kinetics were fitted with the logistic equation to obtain the spreading rate constant (r) and the maximum biosensor response (Δλmax), which is assumed to be directly proportional to the maximum spread contact area (Amax). r was found to be independent of the surface density of integrin ligands. In contrast, Δλmax increased with increasing RGD surface density until saturation at high densities. Interpreting the latter behavior with a simple kinetic mass action model, a 2D dissociation constant of 1753 ± 243 μm−2 (corresponding to a 3D dissociation constant of ~30 μM) was obtained for the binding between RGD-specific integrins embedded in the cell membrane and PLL-g-PEG-RGD. All of these results were obtained completely noninvasively without using any labels

High-resolution 3D mapping of rhizosphere glycan patterning using molecular probes in a transparent soil system

Rhizospheres are microecological zones at the interface of roots and soils. Interactions between bacteria and roots are critical for maintaining plant and soil health but are difficult to study because of constraints inherent in working with underground systems. We have developed an in-situ rhizosphere imaging system based on transparent soils and molecular probes that can be imaged using confocal microscopy. We observed spatial patterning of polysaccharides along roots and on cells deposited into the rhizosphere and also co-localised fluorescently tagged soil bacteria. These studies provide insight into the complex glycan landscape of rhizospheres and suggest a means by which root / rhizobacteria interactions can be non-disruptively studied

Utjecaj zračnog prijevoza na kvalitetu uzoraka krvi

The aim of this study was to establish the impact of air transport on blood samples packaged with and without cooling elements and effect of outdoor temperature on sample quality. Venous samples from 38 blood donors in winter and 36 in summer were tested for hemolysis and complete blood count. One tube per subject was kept in controlled conditions at +4 °C. Two sets of tubes were sent by plane from Zagreb to Brussels, one with and one without cooling elements, and another two sets were sent to London following the same principle. Packages with cooling elements were stored in controlled warehousing conditions at airports (+2 °C to +8 °C), whereas packages without cooling elements were stored in ambient warehouse conditions. Data loggers were used for temperature monitoring. Our research revealed statistically significant differences in several hematologic parameters when comparing the samples stored in controlled laboratory conditions and those transported by plane. These differences were more pronounced in the samples transported during the summer. Transport conditions without cooling elements had additional negative impact on the sample quality. Transport of samples using cooling elements and controlled warehousing conditions at airports are sometimes not sufficient to maintain laboratory storage conditions.Cilj ovog istraživanja bio je utvrditi utjecaj zračnog prijevoza na uzorke krvi pakirane s rashladnim elemenatima i bez njih, kao i utjecaj vanjske temperature na kvalitetu uzorka. U venskim uzorcima 38 darivatelja krvi tijekom zime i njih 36 tijekom ljeta određeni su stupanj hemolize i kompletna krvna slika. Jedan uzorak po ispitaniku ostavljen je u kontroliranim uvjetima na +4 °C. Dva seta uzoraka poslana su zrakoplovom iz Zagreba u Bruxelles, jedan s rashladnim elemenatima i jedan bez njih, a druga dva seta poslana su u London po istom načelu. Pakovanja s rashladnim elementima čuvana su u kontroliranim skladišnim uvjetima u zračnim lukama (+2 °C do +8 °C), dok su pakovanja bez rashladnih elemenata čuvana u ambijentnim skladišnim uvjetima. Uređaji za kontinuirano mjerenje temperature korišteni su za nadzor temperature tijekom transporta. Naše istraživanje otkrilo je statistički značajne razlike u nekoliko hematoloških parametara kada se uspoređuju uzorci pohranjeni u kontroliranim laboratorijskim uvjetima i oni koji se transportiraju zračnim prijevozom. Te su razlike bile izraženije u uzorcima transportiranim tijekom ljeta. Uvjeti transporta bez rashladnih elemenata imali su dodatni negativni utjecaj na kvalitetu uzoraka. Transport uzoraka pomoću rashladnih elemenata i kontrolirani uvjeti skladištenja u zračnim lukama ponekad nisu dovoljni za održavanje laboratorijskih uvjeta skladištenja

Microcosm fabrication platform for live microscopy of plant-soil systems

Our ability to fully understand how plants acquire water and nutrients from the soil is constrained by the limitations of current technologies. Soil structures and properties are complex, dynamic, and profoundly modified by root and microbial secretions. Detailed descriptions of soil properties are rarely available to the researcher because natural soil is opaque, making direct observations challenging. To address these experimental difficulties, microcosm systems dedicated to live imaging of rhizosphere processes in highly controlled environmental conditions were developed. The system is based on fluorinated granular materials with low refractive indices, termed transparent soils. Microcosm chambers were assembled using poly(dimethyl siloxane) parts (PDMS) fabricated by injection moulding and subsequently joined to glass slides. The control of liquid fluxes in the microcosm was achieved by syringes passing through the PDMS parts or through custom made PDMS sponges. The platform was tested for live imaging experiments using Light Sheet Fluorescence microscopy. Results demonstrated that the platform is suitable for a diverse range of experiments, including live observation of plant roots, split-soil systems and investigations into the effects of soil heterogeneity, controlled water content experiments, and dye tracer monitoring. The technique was used to quantify the increase in infiltration rate due to the presence of roots in soil. This study demonstrates the potential of combining new materials and microfabrication techniques to overcome current limitations on plant-soil interaction research

DISTRIBUTION OF THE MAIN ABO BLOOD GROUP ALLELES IN CROATIAN POPULATION

Raspodjela krvnih grupa ABO varira diljem svijeta u različitim populacijama, ali i unutar subpopulacija. Cilj rada je prikazati razdiobu 5 glavnih alela ABO sustava (O1, O2, A1, A2 i B) u hrvatskoj populaciji, te ih usporediti s drugim nacijama. Istraživanje je provedeno na 303 uzorka krvi, zdravih, nesrodnih dobrovoljnih davatelja krvi (123 žena, 180 muškaraca) u dobi od 18 do 65 godina. Metode: Nakon izolacije genomske DNA pomoću komercijalnih kolona (QIAamp DNA Blood Mini kit, Qiagen, Njemačka) ili na uređaju MagNA Pure Compact (Roche Diagnostics Corporation, SAD), određeni su genotipovi ABO pomoću metode PCR-SSP. Rezultati: Genotipizacijom je utvrđeno 12 genotipova. Najzastupljeniji genotip je O1O1 (37,2 %), pa slijede O1A1 (27,1 %), O1B (15,8 %), A1B (4,3 %), A1A1 (4,0 %), O1A2 (3,6 %), O1O2 (2,6 %), A1A2 (1,7 %), O2A1 (1,7 %), A2B (1,0 %), BB (0,7 %), O2O2 (0,3 %). Među ispitanicima nisu nađena tri rijetka ABO genotipa: A2A2, O2A2, O2B. Alelne frekvencije iznose: O1 – 0,62; O2 – 0,025; A1- 0,21; A2 – 0,035 i B – 0,11. Razdioba alela ABO u Hrvatskoj je usporediva s drugim europskim narodima. Zaključak: Rezultati genotipizacije ABO krvne grupe kod dobrovoljnih davatelja krvi, koji su reprezentativan uzorak hrvatske populacije, od temeljnog su značenja za istraživanja ABO sustava krvnih grupa kao genetičkog čimbenika rizika za neke bolesti, kao i za antropološka ispitivanja.The frequencies of gene polymorphisms of blood groups serve as markers for populations and races. Distribution of ABO blood groups varies among populations and subpopulations around the world. The aim of the study was to determine distribution of the 5 main alleles of ABO system among Croatian blood donors and compare them with other populations. Material and Methods: The study included 303 samples of healthy unrelated volunteer blood donors, 123 female and 180 male, aged 18-65 years, as a representative sample population of Croatia. After isolation of genomic DNA using commercial columns (QIAamp DNA Blood Mini Kit, Qiagen, Germany) or on the Magna Pure Compact (Roche Diagnostics Corp., USA) device, ABO genotypes were determined by the PCR-SSP method. Results: Twelve of 15 ABO genotypes were identifi ed. The most common was O1O1 (37.30%), followed by O1A1 (27.00%), O1B (15.80%), A1B (4.30%), A1A1 (4.00%), O1A2 (3.60%), O1O2 (2.60%), A1A2 (1.70%), O2A1 (1.70%), A2B (1.00%), BB (0.70%), and O2O2 (0.30%). Three rare ABO genotypes, A2A2, O2A2, and O2B, were not identifi ed. The calculated allele frequencies of the fi ve main alleles were as follows: O1, 0.620; O2, 0,025; A1, 0.21; A2, 0,035; and B, 0.11. In the Croatian population, O1 was found to be the most common allele, followed by A1 and B, while O2 allele was the least prevalent one. Conclusion: The distribution of alleles in Croatia is comparable to other European nations. According to the frequency of B allele, the Croatian population is comparable to Eastern Europe, probably due to migration of the population in the past. Results of ABO blood group genotyping have fundamental importance for research of the ABO system as a genetic risk factor for some diseases, as well as for anthropologic testing

Smart soils track the formation of pH gradients across the rhizosphere

Aims Our understanding of the rhizosphere is limited by the lack of techniques for in situ live microscopy. Current techniques are either destructive or unsuitable for observing chemical changes within the pore space. To address this limitation, we have developed artificial substrates, termed smart soils, that enable the acquisition and 3D reconstruction of chemical sensors attached to soil particles. Methods The transparency of smart soils was achieved using polymer particles with refractive index matching that of water. The surface of the particles was modified both to retain water and act as a local sensor to report on pore space pH via fluorescence emissions. Multispectral signals were acquired from the particles using a light sheet microscope, and machine learning algorithms predicted the changes and spatial distribution in pH at the surface of the smart soil particles. Results The technique was able to predict pH live and in situ within ± 0.5 units of the true pH value. pH distribution could be reconstructed across a volume of several cubic centimetres around plant roots at 10 μm resolution. Using smart soils of different composition, we revealed how root exudation and pore structure create variability in chemical properties. Conclusion Smart soils captured the pH gradients forming around a growing plant root. Future developments of the technology could include the fine tuning of soil physicochemical properties, the addition of chemical sensors and improved data processing. Hence, this technology could play a critical role in advancing our understanding of complex rhizosphere processes

New methods in blood component production

Uloga transfuzijske službe jest osigurati dovoljnu količinu sigurnih krvnih pripravaka za liječenje bolesnika. S tim ciljem proizvodnja krvnih pripravaka stalno se unaprjeđuje. Uvode se nove tehnike proizvodnje koje pridonose povećanju kvalitete pripravaka, smanjuju rizik prijenosa uzročnika krvlju prenosivih bolesti i omogućuju bolju iskorištenost krvi. Dok s jedne strane starenje populacije u razvijenim zemljama i sve agresivniji pristupi liječenju mnogih bolesti rezultiraju povećanom potrebom za lijekovima iz krvi, isključivanje potencijalnih davatelja krvi zbog sve strožih zahtjeva za sigurnošću krvi, pojava epidemija zaraznih bolesti i otkrivanje novih uzročnika koji se mogu prenijeti krvlju s druge strane, ograničuju adekvatnu raspoloživost ovih lijekova.The role of transfusion service is to provide adequate amounts of safe blood products. Thus, the blood component production is constantly improved by new techniques that increase the quality of blood products, reduce the risk of blood-borne pathogen transmission and allow better utilization of blood. While aging of the population in developing countries and increasingly aggressive treatment approaches result in an increased need for blood products, the exclusion of potential blood donors due to more rigorous blood safety requirements, emergence of epidemics of infectious diseases and discovery of new blood-borne infections agents limit the adequate availability of blood products