Cell Perimeter Research Articles

Simulation of plant cell shrinkage during drying – A SPH–DEM approach

Plant based dried food products are popular commodities in global market where much research is focused to improve the products and processing techniques. In this regard, numerical modeling is highly applicable and in this work, a coupled meshfree particle-based two-dimensional (2-D) model was developed to simulate microscale deformations of plant cells during drying. Smoothed Particle Hydrodynamics (SPH) was used to model the viscous cell protoplasm (cell fluid) by approximating it to an incompressible Newtonian fluid. The visco-elastic characteristic of the cell wall was approximated to a Neo-Hookean solid material augmented with a viscous term and modeled with a Discrete Element Method (DEM). Compared to a previous work [44], this study proposes three model improvements: linearly decreasing positive cell turgor pressure during drying, cell wall contraction forces and cell wall drying. The improvements made the model more comparable with experimental findings on dried cell morphology and geometric properties such as cell area, diameter, perimeter, roundness, elongation and compactness. This single cell model could be used as a building block for advanced tissue models which are highly applicable for product and process optimizations in Food Engineering.

Nanoscale Mechanical Stimulation of Human Mesenchymal Stem Cells

Introduction: Mechanical stimulation of human mesenchymal stem cells has demonstrated changes in many cell behaviours such as adhesion, migration, growth and differentiation through mechanotransductive pathways. These include experiments on effect of nanotopography 1, shear stress, stiffness of extracellular matrix 2, strain, stress and acoustic wave energy 3 on cells. In this research we were looking for mesenchymal stem cell responses to nanoscale mechanical vibrations in Z-axis. The changes in cell number and shape, differentiation and genetic changes were compared after stimulation with static control groups. Methods: A simple protocol for the stimulation of cells in nanoscale Z-axis has been developed for this project (Figure 1). Piezo actuator (type: P-010.00H by PI CeramicO) connected to the cell culture dish moves the entire surface up and down. The amount of displacement is dependent on the voltage applied. Attaching an aluminium disk to the base of the Petri dish ensures faithful transfer of the vibration to the cells. Human mesenchymal stem cells from bone marrow (PromoCellO) were seeded with 104 cells/dish. After 4 hours seeding and cell settlement, the cells were stimulated for 24 hours, 1 week, and 2 weeks. Experiments were performed in an incubator with optimal temperature 37°C and 5% CO2 concentration. The Petri dish was 60 mm x 15mm standard tissue culture treated polystyrene dish (52mm base diameter) from CorningO Incorporated and cell culture media used was MEM alpha modification with L-Glutamine and nucleosides from PAA laboratories (Austria) supplemented with 10% FBS and antibiotics (penicillin and streptomycin). Results: We observed significant responses after 1 and 2-week stimulations in cell number, cell shapes and phenotypical markers. Microarray was performed for all groups. Cell count showed normal cell growth with stimulation. However, cell surface area, cell perimeter, and arboration after 1-week stimulation showed significant increases. Immunofluorescent studies have showed significant increase in osteocalcin production after stimulation. Conclusions: Nanoscale mechanical vibration showed significant changes in human mesenchymal stem cell behaviours. Cell morphology changed to become more polygonal and increased expression of the osteoblast markers were noted. These findings with gene regulation changes suggesting nanoscale mechanostimulation has stimulated osteoblastogenesis. Keywords: Mesenchymal, Nanoscale, Stem Cells.

Vaginal cytology after induction of ovulation in the queen: comparison of postoestrus and dioestrus

To compare the vaginal cytology of ovulating and non-ovulating queens. The study group comprised 15 queens showing behavioural oestrus. Ovulation was induced in 7 (dioestrus group) and 8 were left untreated (postoestrus group). Vaginal smears were collected from all animals prior to ovariohysterectomy on day 7. Epithelial cells were classified as basal-parabasal, intermediate, superficial, or anucleated superficial cells and counted using computer-assisted image analysis. From each smear, 50 representative vaginal epithelial cells were chosen. Digital images of cells were taken and cell area, cytoplasm area, nucleus area, cell diameter, cell perimeter, nucleus/cytoplasm ratio and red-green-blue (RGB) values were measured using image analysis software. Measurement data were compared between groups. Ovulation induction was successful in all animals. The swabbing procedure in oestrus did not induce ovulation in any postoestrus queens. Mean duration of oestrus was 6.65 ± 0.44 and 4.71 ± 0.32 days (P > 0.05) in the postoestrus and dioestrus queens, respectively. Intermediate cell count averaged 21.43% in dioestrus cats and 10.76% in postoestrus cats (P < 0.05). Epithelial cells in the postoestrus group had higher cell area, cytoplasm area, cell diameter and cell perimeter measurements (P < 0.01). Red (90.9 ± 1.6), green (76.1 ± 1.3) and blue (83.6 ± 1.4) channel values in postoestrus were higher than the values (81.3 ± 0.8, 65.8 ± 0.9 and 74.0 ± 0.7, respectively) in dioestrus (P < 0.01). Induction of ovulation in oestrus queens results in a significant increase in the number of intermediate cells and a significant decrease in both the dimensions and RGB values of vaginal epithelial cells on day 7.

Scanning Electron Microscopic Study of Microstructure of Gala Apples During Hot Air Drying

Microscopic changes that occur in plant food materials during drying significantly influence the macroscopic properties and quality factors of the dried food materials. It is critical to study the microstructure to understand the underlying cellular mechanisms to improve the performance of food drying techniques. However, there is limited research on such microstructural changes of plant food material during drying. In this work, Gala apple parenchyma tissue samples were studied using a scanning electron microscope for gradual microstructural changes as affected by temperature, time, and moisture content during hot air drying at two drying temperatures: 57 and 70°C. For fresh samples, the average cellular parameter values were as follows: cell area, 20,000 µm2; ferret diameter, 160 µm; perimeter, 600 µm; roundness, 0.76; elongation, 1.45; and compactness, 0.84. During drying, a higher degree of cell shrinkage was observed with cell wall warping and an increase in intercellular space. However, no significant cell wall breakage was observed. The overall reductions in cell area, ferret diameter, and perimeter were about 60, 40, and 30%. The cell roundness and elongation showed overall increments of about 5% and the compactness remained unchanged. Throughout the drying cycle, cellular deformations were mainly influenced by the moisture content. During the initial and intermediate stages of drying, cellular deformations were also positively influenced by the drying temperature and the effect was reversed at the final stages of drying, which provides clues regarding case hardening of the material.

Formation of Transient Lamellipodia

Cell motility driven by actin polymerization is pivotal to the development and survival of organisms and individual cells. Motile cells plated on flat substrates form membrane protrusions called lamellipodia. The protrusions repeatedly appear and retract in all directions. If a lamellipodium is stabilized and lasts for some time, it can take over the lead and determine the direction of cell motion. Protrusions traveling along the cell perimeter have also been observed. Their initiation is in some situations the effect of the dynamics of the pathway linking plasma membrane receptors to actin filament nucleation, e.g. in chemotaxis. However, lamellipodia are also formed in many cells incessantly during motion with a constant state of the signaling pathways upstream from nucleation promoting factors (NPFs), or spontaneously in resting cells. These observations strongly suggest protrusion formation can also be a consequence of the dynamics downstream from NPFs, with signaling setting the dynamic regime but not initiating the formation of individual protrusions. A quantitative mechanism for this kind of lamellipodium dynamics has not been suggested yet. Here, we present a model exhibiting excitable actin network dynamics. Individual lamellipodia form due to random supercritical filament nucleation events amplified by autocatalytic branching. They last for about 30 seconds to many minutes and are terminated by filament bundling, severing and capping. We show the relevance of the model mechanism for experimentally observed protrusion dynamics by reproducing in very good approximation the repetitive protrusion formation measured by Burnette et al. with respect to the velocities of leading edge protrusion and retrograde flow, oscillation amplitudes, periods and shape, as well as the phase relation between protrusion and retrograde flow. Our modeling results agree with the mechanism of actin bundle formation during lamellipodium retraction suggested by Burnette et al. and Koestler et al.

Dynamics of β‐adrenergic/cAMP signaling and morphological changes in cultured astrocytes

The morphology of astrocytes, likely regulated by cAMP, determines the structural association between astrocytes and the synapse, consequently modulating synaptic function. β-Adrenergic receptors (β-AR), which increase cytosolic cAMP concentration ([cAMP]i ), may affect cell morphology. However, the real-time dynamics of β-AR-mediated cAMP signaling in single live astrocytes and its effect on cell morphology have not been studied. We used the fluorescence resonance energy transfer (FRET)-based cAMP biosensor Epac1-camps to study time-dependent changes in [cAMP]i ; morphological changes in primary rat astrocytes were monitored by real-time confocal microscopy. Stimulation of β-AR by adrenaline, noradrenaline, and isoprenaline, a specific agonist of β-AR, rapidly increased [cAMP]i (∼15 s). The FRET signal response, mediated via β-AR, was faster than in the presence of forskolin (twofold) and dibutyryl-cAMP (>35-fold), which directly activate adenylyl cyclase and Epac1-camps, respectively, likely due to slow entry of these agents into the cytosol. Oscillations in [cAMP]i have not been recorded, indicating that cAMP-dependent processes operate in a slow time domain. Most Epac1-camps expressing astrocytes revealed a morphological change upon β-AR activation and attained a stellate morphology within 1 h. The morphological changes exhibited a bell-shaped dependency on [cAMP]i . The 5-10% decrease in cell cross-sectional area and the 30-50% increase in cell perimeter are likely due to withdrawal of the cytoplasm to the perinuclear region and the appearance of protrusions on the surface of astrocytes. Because astrocyte processes ensheath neurons, β-AR/cAMP-mediated morphological changes can modify the geometry of the extracellular space, affecting synaptic, neuronal, and astrocyte functions in health and disease.

Antisickling Activity and Membrane Stabilizing Effect of Anthocyanins Extracts from Adansonia digitata L. Barks on Sickle Blood Cells

Background: Parts of baobab tree (Adansonia digitata) including especially the barks are commonly used for their medicinal properties. Aims: The aim of this work is to evaluate the antisickling activity of baobab tree barks, which are used in Congolese traditional medicine to manage Sickle Cell Disease. Study Design: Baobab tree barks was extracted with water by maceration. Phytochemical tests were conducted with standard procedures. Antisickling activity and the minimum concentration of extract required to normalize sickled cells was determined by Emmel test. Place and Duration of Study: This work was done at department of chemistry, Science Faculty, University of Kinshasa (DR Congo), between November 2012 and February 2013. Methodology: The barks collected from Adansonia digitata were dried and powdered. A chemical screening was perform and extraction of anthocyanins done. Antisickling activity Original Research Article Mpiana et al.; IBRR, Article no. IBRR.2014.5.001 199 was evaluated by Emmel test, membrane stability by osmotic fragility test and Fe evolution by following solution absorbance at 630nm. The rate of sickle cell shape normalization was determined at different plant aqueous extract concentrations in order to determine the minimal concentration of extract required to normalize sickle cells. The shape modification was quantitatively evaluated from the values of parameters such as surface, radius and perimeters of sickle blood cells before or after treatment with plant extract using Motic software. Results: The aqueous extract of Adansonia digitata showed an antisickling activity with a maximal normalization rate of 65.7% and a minimal concentration required to normalize sickled cells of 5.0mg/mL. The cell surface, perimeter and radius were significantly different before and after treatment with plant extract. The chemical screening showed the presence of polyphenols among which anthocyanins. The biological activity of this plant would be due to these pigments. The anthocyanins extract have also shown a stabilization effect on sickle blood red cells membranes and a reduction of methemoglobin to hemoglobin effect Conclusion: The results obtained show significant antisickling activity of Adansonia digitata barks thus justifying the use of this plant by traditional healers in Congolese traditional medicine in the management of Sickle Cell Disease.

Locomotor response to novelty correlates with differences in number and morphology of hypothalamic tyrosine hydroxylase positive cells in rats

Individual differences in the intensity of locomotor response to a new environment (exploratory reaction) are generally used as a model to study individual vulnerability to stress and drug addiction. In the present work we studied the number, distribution and morphology of the hypothalamic cells expressing tyrosine hydroxylase (TH+ cells) (immunohistochemical and immunofluorescent staining) in male Wistar rats divided based on high (HR), midline (MR) or low (LR) locomotor activity in response to novelty. Morphology and total number of TH+ cells were analyzed for A11-A15 dopaminergic groups. We found correlation between the total number of hypothalamic TH+ cells in the whole A11-A15 area and the locomotor activity. The differences were most pronounced in some of the hypothalamic nuclei, i.e. in the rostro-caudal extension of the A11, A12 and A14 structures, where the HR rats had a significantly higher number of TH+ cells in comparison to the MR and LR rats. Morphology analysis of TH+ cells showed HR/MR/LR differences in single cell area and perimeter and, to a lesser extent, in the other morphometric parameters such as length of the major and minor axes, or circularity factor. The results suggest that the behavioral traits which characterize the HR animals and are correlated with increased susceptibility to stress and propensity to develop drug addictions can be determined by the number, distribution, activity and perhaps the morphology of the cells in the dopaminergic systems.

Morphological characteristics and features in sertoli cell ultrastructure experimental varicocele

Established anatomical morphometric characteristics of Sertoli cells in the simulation of varicocele and after treatment. After modeling varicocele perimeter and diameter of the cells and their nuclei was significantly decreased with increasing periods of varicocele. After undergoing surgery to Ivanissevich increased performance area, perimeter and diameter of Sertoli cells and their nuclei, but not enough to normalize their function. Forming operation between veins microvascular anastomosis using the method gives better results Sertoli cell regeneration compared to traditional obstructive operations because it normalizes the nuclear-cytoplasmic ratio and thereby creating more favorable conditions for the restoration of spermatogenic function.

Mesenchymal stem cell secreted platelet derived growth factor exerts a pro-migratory effect on resident Cardiac Atrial appendage Stem Cells

Mesenchymal stem cells (MSCs) modulate cardiac healing after myocardial injury through the release of paracrine factors, but the exact mechanisms are still unknown. One possible mechanism is through mobilization of endogenous cardiac stem cells (CSCs). This study aimed to test the pro-migratory effect of MSC conditioned medium (MSC-CM) on endogenous CSCs from human cardiac tissue. By using a three-dimensional collagen assay, we found that MSC-CM improved migration of cells from human cardiac tissue. Cell counts, perimeter and area measurements were utilized to quantify migration effects. To examine whether resident stem cells were among the migrating cells, specific stem cell properties were investigated. The migrating cells displayed strong similarities with resident Cardiac Atrial appendage Stem Cells (CASCs), including a clonogenic potential of ~21.5% and expression of pluripotency associated genes like Oct-4, Nanog, c-Myc and Klf-4. Similar to CASCs, migrating cells demonstrated high aldehyde dehydrogenase activity and were able to differentiate towards cardiomyocytes. Receptor tyrosine kinase analysis and collagen assays performed with recombinant platelet derived growth factor (PDGF)-AA and Imatinib Mesylate, a PDGF receptor inhibitor, suggested a role for the PDGF-AA/PDGF receptor α axis in enhancing the migration process of CASCs. In conclusion, our findings demonstrate that factors present in MSC-CM improve migration of resident stem cells from human cardiac tissue. These data open doors towards future therapies in which MSC secreted factors, like PDGF-AA, can be utilized to enhance the recruitment of CASCs towards the site of myocardial injury.

Non-uniform Distribution of Outer Hair Cell Transmembrane Potential Induced by Extracellular Electric Field

Intracochlear electric fields arising out of sound-induced receptor currents, silent currents, or electrical current injected into the cochlea induce transmembrane potential along the outer hair cell (OHC) but its distribution along the cells is unknown. In this study, we investigated the distribution of OHC transmembrane potential induced along the cell perimeter and its sensitivity to the direction of the extracellular electric field (EEF) on isolated OHCs at a low frequency using the fast voltage-sensitive dye ANNINE-6plus. We calibrated the potentiometric sensitivity of the dye by applying known voltage steps to cells by simultaneous whole-cell voltage clamp. The OHC transmembrane potential induced by the EEF is shown to be highly nonuniform along the cell perimeter and strongly dependent on the direction of the electrical field. Unlike in many other cells, the EEF induces a field-direction-dependent intracellular potential in the cylindrical OHC. We predict that without this induced intracellular potential, EEF would not generate somatic electromotility in OHCs. In conjunction with the known heterogeneity of OHC membrane microdomains, voltage-gated ion channels, charge, and capacitance, the EEF-induced nonuniform transmembrane potential measured in this study suggests that the EEF would impact the cochlear amplification and electropermeability of molecules across the cell.

Motility efficiency and spatiotemporal synchronization in non-metastatic vs. metastatic breast cancer cells.

Metastatic breast cancer cells move not only more rapidly and persistently than their non-metastatic variants but in doing so use the mechanical work of the cytoskeleton more efficiently. The efficiency of the cell motions is defined for entire cells (rather than parts of the cell membrane) and is related to the work expended in forming membrane protrusions and retractions. This work, in turn, is estimated by integrating the protruded and retracted areas along the entire cell perimeter and is standardized with respect to the net translocation of the cell. A combination of cross-correlation, Granger causality, and morphodynamic profiling analyses is then used to relate the efficiency to the cell membrane dynamics. In metastatic cells, the protrusions and retractions are highly "synchronized" both in space and in time and these cells move efficiently. In contrast, protrusions and retractions formed by non-metastatic cells are not "synchronized" corresponding to low motility efficiencies. Our work provides a link between the kinematics of cell motions and their energetics. It also suggests that spatiotemporal synchronization might be one of the hallmarks of invasiveness of cancerous cells.

Cyclic AMP regulates the migration and invasion potential of human pancreatic cancer cells

Aggressive dissemination and metastasis of pancreatic ductal adenocarcinoma (PDAC) results in poor prognosis and marked lethality. Rho monomeric G protein levels are increased in pancreatic cancer tissue. As the mechanisms underlying PDAC malignancy are little understood, we investigated the role for cAMP in regulating monomeric G protein regulated invasion and migration of pancreatic cancer cells. Treatment of PDAC cells with cAMP elevating agents that activate adenylyl cyclases, forskolin, protein kinase A (PKA), 6-Bnz-cAMP, or the cyclic nucleotide phosphodiesterase inhibitor cilostamide significantly decreased migration and Matrigel invasion of PDAC cell lines. Inhibition was dose-dependent and not significantly different between forskolin or cilostamide treatment. cAMP elevating drugs not only blocked basal migration, but similarly abrogated transforming-growth factor-β-directed PDAC cell migration and invasion. The inhibitory effects of cAMP were prevented by the pharmacological blockade of PKA. Drugs that increase cellular cAMP levels decreased levels of active RhoA or RhoC, with a concomitant increase in phosphorylated RhoA. Diminished Rho signaling was correlated with the appearance of thickened cortical actin bands along the perimeter of non-motile forskolin or cilostamide-treated cells. Decreased migration did not reflect alterations in cell growth or programmed cell death. Collectively these data support the notion that increased levels of cAMP specifically hinder PDAC cell motility through F-actin remodeling.

Degradation mechanism of concentrator solar receivers without protection layer

GaInP/GaInAs/Ge triple junction concentrator solar receivers without protection layer were conducted sequentially at 90, 110, 130 and 150°C for 25, 30, 30 and 50h, respectively. After the step stress accelerated degradation tests (SSADT), gradual degradation in the dark and light I–V characteristics were observed. Degradation of devices results in the decrease of open-circuit voltage (Voc), fill factor (FF) and efficiency. The degradation mechanism of these triple junction concentrator solar receivers is attributed to the recombination current in the depletion region at the chip perimeter of solar cells. The mean time to failure (MTTF) of 380h at 65°C and active energy (Ea) of 0.16eV were obtained by the statistical analysis with cumulative damage and exponential mode. Both of the obtained values of MTTF and Ea are low, and this results might be possibly due to our devices being without encapsulated protection layer.

Abstract 007: Platelet Derived Growth Factor-AA Promotes Migration of Resident Cardiac Stem Cells

Bone marrow mesenchymal stem cells modulate cardiac healing via the release of paracrine factors. Although the exact mechanisms are not yet understood, one promising approach is through the mobilization of endogenous cardiac stem cells. Recently, we reported the existence of a new type of cardiac stem cell, named Cardiac Atrial appendage Stem Cells (CASCs), that is characterized by a high aldehyde dehydrogenase expression. In this study, we hypothesized that conditioned medium from mesenchymal stem cells (MSC-CM) is able to promote migration of resident cardiac stem cells. Therefore, human cardiac fragments were cultured inside a collagen type I matrix and subjected to serum-free DMEM (control) or MSC-CM. By analysis of cell counts, perimeter and area measurements, we found that MSC-CM promoted migration of cells from cardiac fragments throughout the matrix. These migrating cells possessed stem cell properties, as shown by a clonogenicity of 21.6±4.3% (n=3) and pluripotency associated genes like Oct-4, Nanog, Dppa-3, Tbx-3, c-Myc and Klf-4. Flow cytometrical analysis showed that these cells expressed a CSC-phenotype. Further investigation demonstrated that, comparable to CASCs, migrating cells had a high aldehyde dehydrogenase activity and were able to differentiate towards cardiomyocytes. In addition, we demonstrated an extensive activation of the platelet derived growth factor receptor-α (PDGFRα) in migrating cells subjected to MSC-CM. Subsequent collagen assays indicated that pure PDGF-AA was sufficient to produce migration effects similar to MSC-CM, albeit higher PDGF-AA concentrations than measured in MSC-CM were necessary. Imatinib mesylate, a PDGFR inhibitor, was partially able to attenuate MSC-CM induced migration, pointing out that PDGF-AA might work synergistically with other factors to promote migration. In conclusion, these data demonstrate that MSC-CM stimulates migration of resident CASCs. PDGF-AA is an important paracrine factor in this process, although the synergic role of other growth factors has to be further investigated. These findings contribute to the development of future therapies in which paracrine agents can be utilized to activate the endogenous repair system of the heart.

A Reliability Model of Concentrator Solar Receivers

The degradation mechanism of GaInP/GaInAs/Ge triple-junction solar cells without coating with any protective film was analyzed. After the step stress accelerated degradation test (SSADT) was performed on the solar cells under the sequential conditions of 90 °C for 25 h, 110 °C for 30 h, 130 °C for 30 h, and 150 °C for 50 h, the degradation of dark and light current vs voltage (I–V) characteristics was observed. It is supposed that the recombination current in the depletion region at the chip perimeter of solar cells is the most important degradation mechanism for GaInP/GaInAs/Ge triple-junction solar cells as well as the decreases in open-circuit voltage (VOC), fill factor (FF), and energy efficiency (η).

Nesprin-3 connects plectin and vimentin to the nuclear envelope of Sertoli cells but is not required for Sertoli cell function in spermatogenesis

Nesprin-3 is a nuclear envelope protein that connects the nucleus to intermediate filaments by interacting with plectin. To investigate the role of nesprin-3 in the perinuclear localization of plectin, we generated nesprin-3-knockout mice and examined the effects of nesprin-3 deficiency in different cell types and tissues. Nesprin-3 and plectin are coexpressed in a variety of tissues, including peripheral nerve and muscle. The expression level of nesprin-3 in skeletal muscle is very low and decreases during myoblast differentiation in vitro. Of interest, plectin was concentrated at the nuclear envelope in only a few cell types. This was most prominent in Sertoli cells of the testis, in which nesprin-3 is required for the localization of both plectin and vimentin at the nuclear perimeter. Testicular morphology and the position of the nucleus in Sertoli cells were normal, however, in the nesprin-3-knockout mice and the mice were fertile. Furthermore, nesprin-3 was not required for the polarization and migration of mouse embryonic fibroblasts. Thus, although nesprin-3 is critical for the localization of plectin to the nuclear perimeter of Sertoli cells, the resulting link between the nuclear envelope and the intermediate filament system seems to be dispensable for normal testicular morphology and spermatogenesis.

Prediction of Wood Fiber Attributes from LiDAR-Derived Forest Canopy Indicators

We investigated the potential use of airborne light detection and ranging (LiDAR) data to predict key wood fiber properties from extrinsic indicators in lodgepole pine leading forest stands located in the foothills of central Alberta, Canada. Six wood fiber attributes (wood density, cell perimeter, cell coarseness, mature fiber length, microfibril angle, and modulus of elasticity) were measured at 21 plots, and with use of data reduction techniques, two components of wood properties were derived: wood strength, stiffness, and fiber yield and fiber strength and smoothness. These wood fiber components were then compared with extrinsic indicators of wood characteristic-derived LiDAR-estimated topographic morphology, tree height, and canopy light metrics. The first principal component indicating wood strength and stiffness was significantly correlated to the depth of different canopy zones (or light regimes; r 2 0.55, P 0.05). The second component, related to fiber strength and smoothness, was significantly correlated to the height of the canopy and canopy thickness (r 2 0.65, P 0.05). The results indicate that airborne LiDAR attributes can explain about half of the observed variance in intrinsic wood fiber attributes, which is approximately 5-10% less than that explained by growth-related field-measured variables such as diameter increment and height. This reduction in explained variance can be balanced by the opportunities for much broader spatial characterizations of wood quantity and quality at the stand and landscape levels. FOR .S CI. 59(2):231-242.

Trigeminal ganglion morphology in human fetus

The morphology of the trigeminal ganglion in human fetus was investigated by means of the tract-tracing method using the lipophilic dye DiI-C18-(3) (1,1'-double octadecane 3,3,3'3'-tetramethyl indole carbonyl cyanine-perchlorate), hematoxylin-eosin (HE) stain, and three-dimensional computer reconstruction models. The trigeminal ganglion was flat in the dorsoventral direction, and DiI staining revealed that the trigeminal ganglion cells were somatotopically distributed in the ganglion in a way that reflected the mediolateral order of the three branches. Ganglion cells of the ophthalmic nerve were distributed in the anteromedial part of the trigeminal ganglion, those of the mandibular nerve were in the posterolateral part, and those of the maxillary nerve were localized in the intermediate part. DiI labeled both ganglion cells and nerve fibers in the trigeminal ganglion; the ganglion cells varied in size and appeared as round- or oval-shaped, the neurites connected the cell soma, and some bipolar neurons were also observed. The number of embryonic trigeminal ganglion cells did not significantly change with gestational age, but the cell diameter, area, and perimeter significantly increased. The motor root leaves the pons, runs along the sensory root, passes the ventral surface of the ganglion, and finally runs together with the mandibular nerve. The findings reported here elucidate the morphology, development, and somatotopic organization of the trigeminal ganglion and reveal the trigeminal nerve motor root pathway along the trigeminal ganglion and mandibular nerve in the human fetus.

Rhodocetin-αβ–induced Neuropilin-1–cMet Association Triggers Restructuring of Matrix Contacts in Endothelial Cells

The snake venom component rhodocetin-αβ (RCαβ) stimulates endothelial cell motility in an α2β1 integrin-independent manner. We aimed to elucidate its cellular and molecular mechanisms. We identified neuropilin-1 (Nrp1) as a novel target of RCαβ by protein-chemical methods. RCαβ and vascular endothelial growth factor (VEGF)-A avidly bind to Nrp1. Instead of acting as VEGF receptor 2 coreceptor, Nrp1 associates upon RCαβ treatment with cMet. Furthermore, cell-based ELISAs and kinase inhibitor studies showed that RCαβ induces phosphorylation of tyrosines 1234/1235 [corrected] and thus activation of cMet. Consequently, paxillin is phosphorylated at Y31, which is redistributed from streak-like focal adhesions to spot-like focal contacts at the cell perimeter, along with α2β1 integrin, thereby regulating cell-matrix interactions. Cortactin is abundant in the cell perimeter, where it is involved in the branching of the cortical actin network of lamellipodia, whereas tensile force-bearing actin stress fibers radiating from focal adhesions disappear together with zyxin, a focal adhesion marker, on RCαβ treatment. Our data demonstrate that (1) Nrp1 is a novel target for venom components, such as RCαβ; (2) Nrp1 coupled to cMet regulates the type of cell-matrix interactions in a manner involving paxillin phosphorylation; and (3) altered cell-matrix interactions determine endothelial cell migration and cellular force management.