Photosynthesis and water relations of almond tree cultivars grafted on two rootstocks

Five cultivars of Prunus amygdalus Batsch (Ferragnes, Ferrastar, Marcona, Garrigues, and Non Pareil) grafted on two different rootstocks (Garrigues and GF677), and two cultivars (Ferraduel and Casa Nova) grafted on GF677, were grown for three years under rainfed conditions in an orchard in northeast Portugal. Net photosynthetic rate (PN), leaf conductance for water vapour (gs), leaf water potential (Ψ), instantaneous water use efficiency (WUE), and internal CO2 concentration (Ci) were measured at three periods of the growing season: spring, summer (June or July) and late summer (September) over two years. Ferraduel, Ferrastar, and Marcona presented the best performance in the periods when environmental conditions were not very hard (May or September). Casa Nova and Non Pareil were well adapted to high air evaporative demand, preventing the increase of leaf temperature (T1). Ferrastar, although having a good performance in May and September, did well adapt to hard climatic conditions in June 1994. In the following year, although it presented the highest T1, the values were not limiting (30.6 ± 2.1 °C), and PN was only decreased from May to July. Marcona was highly dependent on T1, but prevented its increasing. Garrigues showed lower PN in most measurement periods. GF677 frequently induced the highest PN, WUE, and Ψ. PN was mainly dependent on T1, radiation, Ci, month, and year. WUE depended on the same factors. Ψ depended mainly on gs, air temperature, month, and year. This revised version was published online in June 2006 with corrections to the Cover Date.     

Developmental refinement of hair cell synapses tightens the coupling of Ca2+ influx to exocytosis

Cochlear inner hair cells (IHCs) develop from pre‐sensory pacemaker to sound transducer. Here, we report that this involves changes in structure and function of the ribbon synapses between IHCs and spiral ganglion neurons (SGNs) around hearing onset in mice. As synapses matured they changed from holding several small presynaptic active zones (AZs) and apposed postsynaptic densities (PSDs) to one large AZ/PSD complex per SGN bouton. After the onset of hearing (i) IHCs had fewer and larger ribbons; (ii) Ca_V1.3 channels formed stripe‐like clusters rather than the smaller and round clusters at immature AZs; (iii) extrasynaptic Ca_V1.3‐channels were selectively reduced, (iv) the intrinsic Ca²⁺ dependence of fast exocytosis probed by Ca²⁺ uncaging remained unchanged but (v) the apparent Ca²⁺ dependence of exocytosis linearized, when assessed by progressive dihydropyridine block of Ca²⁺ influx. Biophysical modeling of exocytosis at mature and immature AZ topographies suggests that Ca²⁺ influx through an individual channel dominates the [Ca²⁺] driving exocytosis at each mature release site. We conclude that IHC synapses undergo major developmental refinements, resulting in tighter spatial coupling between Ca²⁺ influx and exocytosis.     

Using lysozyme amyloid fibrils as a means of scavenging aggregation-inhibiting compounds

The aggregation of amyloidogenic proteins is linked to several amyloidoses, including neurodegenerative disorders, such as Alzheimer's or Parkinson's disease. Currently there are very few effective cures or treatments available, despite countless screenings and clinical trials. One of the most challenging aspects of potential anti-amyloid drug discovery is finding which molecules are the actual inhibitors out of mixtures, which may contain hundreds of distinct compounds. Considering that anti-amyloid compounds would interact with the aggregate, this affinity could be used as a means of separating such compounds from ineffective ones. In this work, we attempt to scavenge potential aggregation-inhibiting molecules out of four, different complexity mixtures, ranging from oxidized gallic acid to tea extract, using lysozyme amyloid fibrils. We show that these compounds bind to aggregates with high affinity and can be later separated from them by different methods.     

Bioerosion features of boring polydorid polychaetes in the North Adriatic Sea

Hydrobiologia - Considering the pivotal role played by erosive organisms in the marine habitat and the scanty knowledge of this phenomenon in the Mediterranean Sea, the present study aimed to...     

Engrafting fetal liver cells into multiple tissues of healthy adult mice without the use of immunosuppressants

We have shown the fetal liver cell engraftments into multiple tissues of adult healthy mice, achieved without suppressing the animals’ immune systems. Fetal cells from the livers of male C57Bl/6J Black lineage mice at day 13 to 15 of gestation were injected intravenously into female adult CC57W/MY White mice. The grafting was evaluated by Y-chromosome-specific PCR, cytometric analysis of fluorescently stained donor cells, and histological analysis. All the methods consistently showed the presence of multiple engraftments randomly distributed through the various organs of the recipients. After 60 days, the grafts still constituted 0.1 to 2.75% of the tissues. The grafted cells did not change their appearance in any of the organs except the brain, where they became enlarged. Inflammatory reactions were not detected in any of the histological preparations. The frequency of engraftments was higher in the liver, indicating that similarity between the donor and recipient cells facilitates engraftment. The high inherent plasticity of fetal liver cells underlies their ability to integrate into healthy recipient organs, which can be governed by environmental conditions and connections with neighboring cells rather than by the initial cellular developmental programs. The fact that fetal liver cells can be grafted into multiple tissues of healthy animals indicates that they can be used to replace the natural loss of cells in adult organisms.     

Photosynthesis and water relations of almond tree cultivars grafted on two rootstocks

Five cultivars of Prunus amygdalus Batsch (Ferragnes, Ferrastar, Marcona, Garrigues, and Non Pareil) grafted on two different rootstocks (Garrigues and GF677), and two cultivars (Ferraduel and Casa Nova) grafted on GF677, were grown for three years under rainfed conditions in an orchard in northeast Portugal. Net photosynthetic rate (PN), leaf conductance for water vapour (gs), leaf water potential (Ψ), instantaneous water use efficiency (WUE), and internal CO2 concentration (Ci) were measured at three periods of the growing season: spring, summer (June or July) and late summer (September) over two years. Ferraduel, Ferrastar, and Marcona presented the best performance in the periods when environmental conditions were not very hard (May or September). Casa Nova and Non Pareil were well adapted to high air evaporative demand, preventing the increase of leaf temperature (T1). Ferrastar, although having a good performance in May and September, did well adapt to hard climatic conditions in June 1994. In the following year, although it presented the highest T1, the values were not limiting (30.6 ± 2.1 °C), and PN was only decreased from May to July. Marcona was highly dependent on T1, but prevented its increasing. Garrigues showed lower PN in most measurement periods. GF677 frequently induced the highest PN, WUE, and Ψ. PN was mainly dependent on T1, radiation, Ci, month, and year. WUE depended on the same factors. Ψ depended mainly on gs, air temperature, month, and year.     

Effect of Training and Match Loads on Hamstring Passive Stiffness in Professional Soccer Players

Objective:the purpose of this study was to identify differences in hamstring passive stiffness between the pre-season and in-season periods.Methods:Hamstring strength and passive stiffness were measured in professional male soccer players before and after the pre-season (4 weeks), and after the in-season (6 weeks) periods using an isokinetic dynamometer. Muscle passive stiffness was determined from the slope of the passive torque–angle relationship. External loads (acceleration and jumps) were monitored by GPS and internal loads by questionnaire.Results:Hamstring passive stiffness increased after 10 weeks of training and matches, without changes in passive peak torque and range of motion. The hamstring passive stiffness modifications were associated with the volume and intensity of accelerations and jumps. The individual data analysis also provided some support for the suppression of the biomechanical adaptation in the subjects with relatively large external load.Conclusions:Regular training and match workouts increase hamstring passive stiffness in professional soccer players but the adaptation of muscle-tendon unit passive elements might not occur if players experience excessive mechanical stress.     

Phenomenon of Quantum Entanglement in a System Composed of Two Minimal Protocells

The quantum mechanical self-assembly of two separate photoactive supramolecular systems with different photosynthetic centers was investigated by means of density functional theory methods. Quantum entangled energy transitions from one subsystem to the other and the assembly of logically controlled artificial minimal protocells were modeled. The systems studied were based on different photoactive sensitizer molecules covalently bonded to a non-canonical oxo-guanine::cytosine supramolecule with the precursor of a fatty acid (pFA) molecule attached via Van der Waals forces, all surrounded by water molecules. The electron correlation interactions responsible for the weak hydrogen and Van der Waals chemical bonds increased due to the addition of polar water solvent molecules. The distances between the separated sensitizer, nucleotide, pFA, and water molecules are comparable to Van der Waals and hydrogen bonding radii. As a result, the overall system becomes compressed, resulting in photo-excited electron tunneling from the sensitizer (bis(4-diphenylamine-2-phenyl)-squarine or 1,4-bis(N,N-dimethylamino)naphthalene) to the pFA molecules. Absorption spectra as well as electron transfer trajectories associated with the different excited states were calculated using time dependent density functional theory methods. The results allow separation of the quantum entangled photosynthetic transitions within the same minimal protocell and with the neighboring minimal protocell. The transferred electron is used to cleave a “waste” organic molecule resulting in the formation of the desired product. A two variable, quantum entangled AND logic gate was proposed, consisting of two input photoactive sensitizer molecules and one output (pFA molecule). It is proposed that a similar process might be applied for the destruction of tumor cancer cells or to yield building blocks in artificial cells.     

Longitudinal monitoring of cell metabolism in biopharmaceutical production using label-free fluorescence lifetime imaging microscopy

Chinese hamster ovary (CHO) cells are routinely used in the biopharmaceutical industry for production of therapeutic monoclonal antibodies (mAbs). Although multiple offline and time-consuming measurements of spent media composition and cell viability assays are used to monitor the status of culture in biopharmaceutical manufacturing, the day-to-day changes in the cellular microenvironment need further in-depth characterization. In this study, two-photon fluorescence lifetime imaging microscopy (2P-FLIM) was used as a tool to directly probe into the health of CHO cells from a bioreactor, exploiting the autofluorescence of intracellular nicotinamide adenine dinucleotide phosphate (NAD(P)H), an enzymatic cofactor that determines the redox state of the cells. A custom-built multimodal microscope with two-photon FLIM capability was utilized to monitor changes in NAD(P)H fluorescence for longitudinal characterization of a changing environment during cell culture processes. Three different cell lines were cultured in 0.5 L shake flasks and 3 L bioreactors. The resulting FLIM data revealed differences in the fluorescence lifetime parameters, which were an indicator of alterations in metabolic activity. In addition, a simple principal component analysis (PCA) of these optical parameters was able to identify differences in metabolic progression of two cell lines cultured in bioreactors. Improved understanding of cell health during antibody production processes can result in better streamlining of process development, thereby improving product titer and verification of scale-up. To our knowledge, this is the first study to use FLIM as a label-free measure of cellular metabolism in a biopharmaceutically relevant and clinically important CHO cell line.