Internodal Space Research Articles

Fertiliser supplementation with a PGR complex of chlormequat chloride (CCC) and paclobutrazol (PBZ) alters Cannabis sativa growth

ABSTRACT Cannabis (Cannabis sativa) is a high-value crop, wherein growth within controlled environments is common for the purposes of maximising yield, quality, and uniformity, however, uncontrolled-growth in proximity to artificial lighting can compromise yields. Within the floricultural industry it is common practice to apply plant growth regulators (PGRs) to retard plant growth and maximise yield and quality, with two well-established PGRs being chlormequat chloride (CCC) and paclobutrazol (PBZ). Accordingly, the aim of this study was to investigate the potential of a PGR complex of CCC and PBZ for novel application to cannabis to control plant height. Treatment of cannabis with the PGR complex within an indoor hydroponic growth system resulted in a 91.1% reduction in post-treatment plant growth (p < 0.001) leading to plants with end-point height and internodal spacing (INS) 0.568-fold (p < 0.001) and 0.469-fold (p < 0.001) shorter than control plants, respectively. These results demonstrate the capacity of CCC and PBZ to beneficially halt the growth of cannabis. Accordingly, application of these PGRs in combination may be utilised to restrict cannabis height without compromising yield within commercial cultivation.

Performance Evaluation of Four Novel Cassava (Manihot esculenta Crantz) Accessions to Different Fertilizer Types in Awka, Anambra State, Nigeria

The investigation was carried out on the effects of fertilizer and cassava variety on agronomic characteristics, yield, and disease incidence of four improved cassava accessions. The experiment was carried out at the Teaching and Research farm of Crop Science and Horticulture, Nnamdi Azikiwe University Awka, Anambra State. It was a 4 × 3 factorial experiment with treatments laid out in a Randomized Complete Block Design (RCBD) with three replications. Fertilizer types were NPK 15:15:15 at a rate of 400 kg/ha, poultry manure (PM) at a rate of 50 tons/ha and no application as control. The cassava accessions were TMS539, TMS092, TMS371 and TMS412, obtained from the International Institute for Tropical Agriculture (IITA) in Ibadan, Nigeria. Stems were cut to about 15cm and planted at a spacing of 0.5m apart. The parameters measured were the number of root tubers, total number of rot tubers, weight of tuber (kg), stem girth (cm), node per stand, branching interval, internode spacing (cm), number of branching, plant height (cm), age at branching, disease incidence. Normal agronomic practices were carried out. Results showed that all varieties responded to the application of inorganic and organic fertilizers. Cassava plants that did not receive any fertilizer application (no application) gave the highest number of root tubers (29.7) from TMS412, and the least was from TMS092. The result also showed that there was no significant difference in the effects of fertilizer type on diseases. Results also showed that there was a significant interactive effect of cassava varieties and fertilizer type on branching interval (7.009), Internode spacing (0.6195), number of branching (0.2822), and plant height (17.02) at six months after planting. From the investigation, it could be recommended that for farmers to obtain greater yields with little or no fertilizer application, these cassava accessions should be used, which are characterized by high yield and resistance to disease and pests, as shown from this research.

The influence of internode geometry on the bearing capacity of parallel chord wood trusses

The influence of two factors, web angle and internode spacing, on the bearing capacity of three different configurations of trusses was investigated. The constitutive model of the bearing capacity of trusses was established which are jointly controlled by web angle and internode spacing. With bearing capacity and stability as calculation indexes, the critical web angle and internode spacing values for three different configurations of trusses were obtained quantitatively, the truss structure was designed by combining web angle and internode spacing, the mid-span displacement was further calculated as a theoretical basis for finite element simulation. A bearing capacity test on truss specimens with Spruce-Pine-Fir (SPF) as the base material was conducted using the obtained results. The relationship between the load displacement of the different geometric configurations of trusses and the main failure modes was determined accordingly. Finally, the constitutive model of bearing capacity was established which is jointly controlled by web angle and internode spacing. It was found that the stability of the bearing capacity of the A-type truss (Warren type with vertical bar) increases with an increase in the web angle, but is relatively unaffected by the web angle compared to other truss types. The bearing capacity of the B-type(Warren type) truss increases as the web angle increases and is markedly affected by the web angle. The bearing capacity of the C-type(Pa type) truss decreases as the web angle increases, but this configuration is less affected by the web angle than the B-type. The influence of internode spacing on the load-carrying capacity of the truss weakens with an increase in the web angle, as well. The constitutive model, which was obtained by theoretical calculation and ABAQUS finite element simulation, is valid within the elastic deformation range but is not applicable beyond the elastic deformation range.

Triggers of Guillain-Barré Syndrome: Campylobacter jejuni Predominates.

Guillain-Barré syndrome (GBS) is a rare immune-mediated acute polyradiculo-neuropathy that typically develops after a previous gastrointestinal or respiratory infection. This narrative overview aims to summarise and discuss current knowledge and previous evidence regarding triggers and pathophysiology of GBS. A systematic search of the literature was carried out using suitable search terms. The most common subtypes of GBS are acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). The most common triggers of GBS, in three quarters of cases, are previous infections. The most common infectious agents that cause GBS include Campylobacter jejuni (C. jejuni), Mycoplasma pneumoniae, and cytomegalovirus. C. jejuni is responsible for about a third of GBS cases. GBS due to C. jejuni is usually more severe than that due to other causes. Clinical presentation of GBS is highly dependent on the structure of pathogenic lipo-oligosaccharides (LOS) that trigger the innate immune system via Toll-like-receptor (TLR)-4 signalling. AIDP is due to demyelination, whereas in AMAN, structures of the axolemma are affected in the nodal or inter-nodal space. In conclusion, GBS is a neuro-immunological disorder caused by autoantibodies against components of the myelin sheath or axolemma. Molecular mimicry between surface structures of pathogens and components of myelin or the axon is one scenario that may explain the pathophysiology of GBS.

Past Human Mobility Corridors and Least-Cost Path Models South of General Carrera Lake, Central West Patagonia (46° S, South America)

Understanding the use of natural corridors is critical for characterizing the past use of marginally occupied landscapes at the Andean fringes of western Patagonia by the hunter-gatherer groups who inhabited this region. In this paper, we combine least-cost path models and archaeological surveys and excavations to determine the possible movements along the southern margin of General Carrera Lake. The methodology includes defining uncertainties that allow for modeling a set of equiprobable routes, thereby avoiding problems with errors and biases from predictors, such as slope, land-use cover, and seasonality. The results identify mobility corridor bottlenecks, i.e., geographical areas with a high probability of travel routes with equiprobable routes that converge. In addition, we identify areas where travel routes are likely to diverge into multiple semi-parallel routes. The study of archaeological sites provides stratigraphic data to control for the chronology and characteristics of mobility along this transect. The correlation between archaeological sites and paths, specifically for the control and winter scenarios, shows the quality of these route predictions. These results indicate the repeated use of internodal spaces that were effectively incorporated into mobility during the last three millennia.

Modeling and simulation of static and dynamic behavior in composite sandwich plates with hourglass lattice cores based on reduced-order model

The composite sandwich plate with hourglass lattice cores (CSP-HLC) is a novel cellular structure that can increase the width-to-length ratio and reduce the inter-node spacing. However, its static and dynamic behaviors are difficult to analyze due to the complex microstructures. In this work, a computational homogenization method is proposed for calculating the constitutive parameters. A reduced-order plate model is then derived through dimensional reduction from the three-dimensional orthotropic thermoelasticity framework. The effectiveness and accuracy of the proposed model were verified by comparing with the static-displacement and free-vibration results of 3D direct numerical simulations. The parameter analysis showed that the different material and structural parameters of the hourglass lattice core had different effects on the equivalent stiffnesses and natural frequencies of the CSP-HLC. Compared with the composite sandwich plate with pyramidal lattice cores, the displacement of the CSP-HLC was smaller under the same load and boundary conditions, and the natural frequencies were also smaller, which may have been because the additional equivalent density of the CSP-HLC influenced the frequency more predominantly than the extra equivalent stiffness.

Assessing the potential for soybean yield improvement through plant architectural modification

AbstractSoybean yield potential can be increased by increasing the number of pods per plant, which can be achieved by increasing the number of nodes per plant while decreasing internode length to prevent lodging due to excessive height. In an effort to discover the genetic variability for this trait, a genome wide association study (GWAS) was performed on 451 diverse lines from the USDA core collection for height, internode length, and the number of nodes. The QTL signifying Dt1 was found correlating to height and quantity of nodes, but no significant QTL for internode spacing were uncovered. From our evaluation, this suggests that genomic selection for variation plant height is feasible; however, no specific genetic trait was detected to select for internode spacing.

Node of Ranvier Spacing Along Single Axons is Prefigured by Clusters of Neuronal Neurofascin

The spacing of nodes of Ranvier crucially affects conduction properties along myelinated axons. It has been assumed that node position is primarily driven by the growth of myelin sheaths. Here, we show through longitudinal live imaging of node formation dynamics that stable clusters of the nodal cell adhesion molecule Neurofascin A accumulate at specific sites along axons prior to myelination. These sites are predictive of future node position as they can restrict extension of developing myelin sheaths. Animals that lack neuronal full-length Neurofascin A showed increased internodal distances and less regular spacing of nodes along single axons. Together, our data show that the axon can prefigure the position of its nodes of Ranvier and thus determine internodal spacing.

Design considerations for low-margin elastic optical networks in the nonlinear regime [Invited

We demonstrate from a system design perspective that nonlinearity can be exploited to minimize the impact of system margins on system performance for both point-to-point links and elastic optical networks. A nonlinear interaction causes a 2 dB reduction in launch power to be reduced to $ \lt\!{0.25}\,\,{\rm{dB}}$ signal-to-noise ratio (SNR) penalty, and likewise, a 2 dB peak–peak (pk-pk) perturbation to the output power of an optical amplifier is reduced to $ \lt\!{0.25}\,\,{\rm{dB}}$ SNR penalty (for 5, 10, and 20 spans). Extending this to a gain ripple of 1 dB pk-pk with an internode spacing of ${5} \times {80}\,\,{\rm{km}}$, ${10} \times {80}\,\,{\rm{km}}$, and ${20} \times {80}\,\,{\rm{km}}$, the penalty is 0.4 dB, 1.5 dB, and 5.1 dB, respectively, with pre-emphasis reducing this to 0.01 dB, 0.3 dB, and 1.2 dB, respectively. In elastic optical networks, we consider the nonlinear relationship among SNR, margin, and the fraction of capacity available. We consider scaling internode distances of a 9-node German scale network (DT9), such that the initial network diameter increases from 1120 km to 6720 km (six-fold scaling). We generate 1000 different topologies based on the scaled DT9 node locations to quantify the impact of margin. For the unscaled DT9 network, a 3 dB margin results in, on average, a 21% reduction in network throughput; however, when the internode spacing is increased six-fold to a continental scale network, the network throughput is reduced by 40%, on average, for the same 3 dB margin.

Mycostimulation in a glyphosate treated arable soil: implications on the yield and agronomic characters of &lt;i&gt;Talinum fruticosum&lt;/i&gt; (L.) Juss

The use of pesticide, although increases agricultural yield and improves public health is also fraught with a number of ecologic, agronomic and health concerns. This research investigated the impact of an ex-situ mycostimulation of one of the in-situ soil fungi on some agronomic characters and yield of Talinum fruticosum planted on a herbicide treated soil. Experimental site was laid out in a 3×8 Randomised Complete Block Design (RCBD). Amongst other fungal species found in the soil, Paecilomyces variotii was selected for multiplication and reintroduction to the field 96 hours after the application of glyphosate and 48 hours after the transfer of T. fruticosum from the nursery. Data on agronomic parameters were taken between the 1 – 6 weeks after planting (WAP) while data on the biomass yield (kgha-1) was taken (on harvesting) at 6 WAP. Data were mean values from 8 replicates and analysed using the statistical package IBM SPSS version 20. Mean values were separated for statistical significance at 95% confidence interval, using the Least Significant Difference (LSD). The results showed that the Treatments had significant (P&lt;0.05) effects on height of plants, density of plants, size of leaves and internode spacing at the different WAP as well as the biomass and yield of Talinum at 6 WAP. The results obtained from the present study thus further reaffirm the crucial role of fungi as nature’s original recyclers. If properly managed and stimulated, fungi can contribute significantly to improving soil health, thus improving food security in a sustainable manner. Keywords: Mycoaugmentation, herbicide, Talinum fruticosum, Paecilomyces variotti, Soil health.

S48 Axonal excitability, Schwann cells and the ‘Barrett-Barrett conductance’

In 1982, Ellen and John Barret published a paper on the depolarizing afterpotential in lizard axons which showed that it was due to passive spread of current from the nodal action potential to the internodal axolemma. The revolutionary electrical model of myelinated axons that they proposed was later found crucial to understanding the excitability changes recordable from human axons in the recovery cycle and threshold electrotonus. A key parameter in their new model was a resistive path across the Schwann cells, between the internodal periaxonal space and the external medium, and its conductance is known in their honour as the ‘Barrett-Barrett conductance’ (GBB). In recent years it has proved possible to understand quite well, by mathematical modelling,the changes in axonal excitability produced by changes in axonal membrane potential, and in the conductances of the major axonal voltage-dependent ion channels (sodium, fast and slow potassium, and HCN), such as in toxic and genetic channelopathies. Less well understood, however, are the complex excitability changes occurring in most demyelinating and other neuropathies that affect Schwann cells and the structure of myelinated axons. This review will bring together a few disparate genetic and auto-immune conditions in which modelling suggests that axonal excitability abnormalities are primarily due to Schwann cell dysfunction and an increase in the ‘Barrett-Barrett’ conductance. In some cases only, this increase appears to be accompanied by an increase in nodal fast potassium conductance, as might be expected for paranodal demyelination with exposure of juxtaparanodal potassium channels.

English

The Zizania latifolia Griseb. Turcz. ex Stapf., a perennial wetland wild rice species get infected by a basidiomycetous fungus Ustilago esculenta Henn that produces gall. Here we report the morphogenesis behaviour of this plant during gall transformation. The identity of Z. latifolia and U. esculenta were confirmed by comparing microsatellite and Internal Transcribed Spacer region of nuclear ribosomal DNA sequence with the public database. U. esculenta infection transforms the Z. latifolia into two distinct morphotypes such as gall forming and non-gall forming. The non-gall bearing morphotype exhibited pinkish microporous lamellar discs (15-20 numbers) filled with mycelia in the internodal spaces. Whereas the gall bearing morphotype fuses 3-4 nodes into compact spindle shaped hypertrophic tissue measuring 2.5 cm diameter x 8-10 cm length tapering at the tip end where dark brown coloured teliospores are deposited in linear sori. In vitro culture of lamellar discs and teliospores in Potato Sucrose Agar medium initially develops white colony 2.6- 4.0 cm diameter later turned into yellowish brown after 7 -10 days and subsequent sporulation within 8-12 days. Spherical sporangium of 28 µm diameter developed on long sporangiophore 7 µm diameter filled with large number of spores 1-1.5 µm in diameters. The unsuccessful sporulation of Ustilago even after infection failed to develop gall in the host plants behave normal life cycle and are not consumed. The spore along with hypertrophic soft tissue is consumed as vegetable in the oriental countries. Key words: Manchurian wild rice, teliospore, microsatellite.

First Biological Data ofCeresa nigripectus(Hemiptera: Membracidae), a Common Treehopper on Alfalfa Crops in Argentina

Alfalfa (Medicago sativa L.; Fabaceae) is essential for argentinean agricultural develop- ment, but diseases like witchesbroom», caused by the ArAWB phytoplasma, are limiting factors for the production of this crop. Insects that visit alfalfa have been poorly studied. The treehopper, Ceresa nigripectus Remes Lenicov (Hemiptera: Membracidae) is very fre- quent in alfalfa crops; ArAWB was detected in several individuals of this treehopper, but the ability of this species to transmit the pathogen has not yet been demonstrated. The Membracidae family is a poorly studied group in Argentina. No data on the biology of C. nigripectus are available, and therefore the aim of this contribution is to provide information on its behavioral and biological parameters as a first step toward its control. The studies were conducted in the laboratory under controlled conditions. Ceresa nigripectus popula- tions were maintained on healthy alfalfa plants; the treehoppers were checked daily, the occurrence of molts was noted, and diverse aspects of nymphal and adult behavior were also recorded. A life table was built combining the observational data from 7 cohorts. Oviposi- tion sites were characterized by dissecting plants and through staining methods. Ceresa nigripectus could complete its life cycle entirely by using only alfalfa as a host. Females do not tend their broods. Eggs are laid individually and rarely 2 or 3 were found in the same slit. Eggs were located in the stems, in the nodes (in the axils of the leaves) or in the internodal space, between the epidermis and cortical tissues. The pre-ovipositional period was about 6 days, and the average duration of the egg stage was 20 days. The duration of nymphal period was variable, between 32 to 63 days, with a mean of 45 days. Two periods of high mortality were recognized, i.e., in the first instar, and during the second week of the adult stage. Longevity of adults averaged 61 days, but some individuals survived up to 202 days; females lived longer than males. In laboratory colonies, the sex ratio was about 1.3:1 females:males. All the developmental stages of the treehopper were tended by the ant Camponotus punctulatus Mayr. Data regarding behavioral aspects and new distributional information are also provided.

Heading cuts and prohexadione-calcium affect the growth and development of ‘d’Anjou’ pear shoots in a high-density orchard

Prohexadione calcium (P-Ca) has been shown to effectively reduce the vigor of pear trees. However, an analysis of the effects of P-Ca on growth and development of headed and unheaded shoots has not been performed. Therefore, P-Ca was selectively applied to dormant-headed (1/3rd removed) and unpruned shoots in a high-density ‘d’Anjou’ pear orchard in Oregon, USA. Both sets of shoots were treated with 250mgL−1 P-Ca in either a single or double application and compared to controls. The first application was delivered to shoots when ∼5cm of new growth accrued; the second, only if shoot growth resumed. P-Ca reduced shoot growth of both headed and unpruned shoots relative to their respective controls. Growth of unpruned shoots ceased 3 weeks following the first P-Ca application. In contrast, headed shoots required 6 weeks from the initial application to cease elongating. A markedly higher maximum shoot growth rate (mmd−1) was observed for headed shoots treated with P-Ca compared to unpruned shoots treated with P-Ca. At 87 days after full bloom, P-Ca-treated, unpruned shoots had a pronounced second flush of growth requiring an additional application of P-Ca. This growth resumption was 2 weeks earlier than unpruned, control shoots and 17d earlier than P-Ca-treated, headed shoots, for which only a negligible growth flush was observed. At the end of the season, unpruned shoot length was decreased by 28% and 41% for shoots treated with P-Ca once or twice, respectively, while headed shoots were 37% shorter than their controls (treated only once). The number of nodes and average internode length were significantly reduced for P-Ca-treated shoots, irrespective of pruning level, conferring a higher node density relative to control shoots. An increase in node density should result in higher yield efficiency once fruiting occurs on this wood. Heading, in contrast, increased the internodal space and decreased the number of nodes, ultimately decreasing node density. We did not observe any physiological effects on the growth or development of adjacent, untreated shoots originating from identical scaffolds as P-Ca-treated shoots. Collectively, these results implicate P-Ca as a powerful tool for precision-management of tree vigor in intensive pear plantings via selective treatment to areas of high vigor.

Theoretical principles underlying optical stimulation of myelinated axons expressing channelrhodopsin-2

Numerous clinical conditions can be treated by neuromodulation of the peripheral nervous system (PNS). Typical electrical PNS therapies activate large diameter axons at lower electrical stimulus thresholds than small diameter axons. However, recent animal experiments with peripheral optogenetic neural stimulation (PONS) of myelinated axons expressing channelrhodopsin-2 (ChR2) have shown that this technique activates small diameter axons at lower irradiances than large diameter axons. We hypothesized that the small-to-large diameter recruitment order primarily arises from the internodal spacing relationship of myelinated axons. Small diameter axons have shorter distances between their nodes of Ranvier, which increases the number of nodes of Ranvier directly illuminated relative to larger diameter axons. We constructed “light-axon” PONS models that included multi-compartment, double cable, myelinated axon models embedded with ChR2 membrane dynamics, coupled with a model of blue light dynamics in the tissue medium from a range of different light sources. The light-axon models enabled direct calculation of threshold irradiance for different diameter axons. Our simulations demonstrate that illumination of multiple nodal sections reduces the threshold irradiance and enhances the small-to-large diameter recruitment order. In addition to addressing biophysical questions, our light-axon model system could also be useful in guiding the engineering design of optical stimulation technology that could maximize the efficiency and selectivity of PONS.

Comparative Study of Morphological and Histological Changes between Differently Structured Expanded Polytetrafluoroethylene Implants in an Animal Model

Expanded polytetrafluoroethylene (e-PTFE) is a popular graft material used in augmentation rhinoplasty. New e-PTFE has thicker fibrils and is more compact than first developed e-PTFE. This study aimed to compare morphological and histological changes between differently structured e-PTFE implants in a rat model. Two types of e-PTFE were implanted in the cranial region of 30 adult male rats. En bloc specimens containing the implants and surrounding soft tissues were sampled 1, 3, and 6 months after implantation. We measured the three-dimensional size of the implants over time and evaluated histological changes using light and electron microscopy. Grossly, no implants were extruded, and there was no evidence of wound infection. All first developed e-PTFE samples were fixed to surrounding tissues after 1 month, whereas new e-PTFE samples tended to migrate and were easily separated from surrounding tissues until 3 months after implantation. The first developed e-PTFE height diminution rate was 14.7% of the initial value after 6 months; however, new e-PTFE size was not changed. Diameter and height diminution rates for first developed e-PTFE were significantly greater than those for new e-PTFE after 6 months. Histologically, connective tissue in growth was observed in first developed e-PTFE after 1 month, and the internodal space decreased over time; however, connective tissue did not infiltrate into new e-PTFE until 6 months and the internodal space was not significantly changed. First developed e-PTFE should be carefully trimmed in augmentation because of its potential to decrease in size over time, whereas new e-PTFE is more likely to show migration and instability.

Modeling and simulating the nerve axon as a thin-film microstrip

Since Hodgkin and Huxley described the nerve axon as a cable (H–H model), many efforts have been made to find more approximated transmission line models representing the nerve axon. This paper describes a simple model that represents the nerve axon in two parts: the internodal space as a lossy thin-film microstrip line and the node of Ranvier as an active complex load. The complex load terminating the transmission line is given by the variable impedance of a tunnel diode. First, the internodal space is circuitally analyzed and electromagnetically simulated as a lossy thin-film microstrip line terminated on a complex fixed load. The transmission line circuit theory, the two-port network analysis, and a two-dimensional finite difference time domain method are used for such a task by forcing a strip subatomic metallization. Then, the transfer function of the internodal space, cascaded with the node of Ranvier, is equated to the transfer function of a transmission line section that includes a tunnel diode. This procedure is carried out in order to obtain the diode's variable impedance. The diode was introduced by Nagumo, Arimoto, and Yoshizawa for simulating the nerve axon as an active transmission line. The active transmission line is represented by the FitzHugh simplified H–H model known as the Bonhoeffer–van der Pol model.

Surface acoustic wave induced particle manipulation in a PDMS channel—principle concepts for continuous flow applications

A device for acoustic particle manipulation in the 40 MHz range for continuous-flow operation in a 50 μm wide PDMS channel has been evaluated. Unidirectional interdigital transducers on a Y-cut Z-propagation lithium nixobate wafer were used to excite a surface acoustic wave that generated an acoustic standing wave inside the microfluidic channel. It was shown that particle alignment nodes with different inter-node spacing could be obtained, depending on device design and driving frequency. The observed inter-node spacing differed from the standard half-wavelength inter-node spacing generally employed in bulk acoustic transducer excited resonant systems. This effect and the related issue of acoustic node positions relative the channel walls, which is fundamental for most continuous flow particle manipulation operations in channels, was evaluated in measurements and simulations. Specific applications of particle separation and alignment where these systems can offer benefits relative state-of the art designs were identified.

Histologic changes in transplanted expanded polytetrafluoroethylene in an animal model

Several materials have been used for nasal augmentation surgery. Expanded polytetrafluoroethylene (e-PTFE) (Gore-Tex; W. L. Gore & Associates, Flagstaff, AZ) has proven to be an ideal synthetic material for nasal augmentation. Gore-Tex contains numerous pores that stabilize an implant, but this advantage has been tempered by unpredictable outcomes. The purpose of this study was to evaluate morphologic and histologic changes in nonreinforced Gore-Tex in a rabbit model. In vivo study using a rabbit model. To analyze histologic changes, we used 20 New Zealand white rabbits. Gore-Tex was implanted into the nasal dorsum of the rabbits. Then, en bloc specimens containing the implant and surrounding soft tissues were sampled 1, 3, 6, and 12 months after implantation. We evaluated the three-dimensional size of the implants over time using light and electron microscopy to investigate histologic and morphologic changes. Following gross analysis, none of the implants were lost or extruded, and there was no evidence of wound infection. Diminution rates of thickness, width, and height in the implants were 22%, 2%, and 5%, respectively. Histologically, connective tissue growth was observed in all specimens, and the internodal space decreased owing to connective tissue ingrowth over time. Neovascularization was observed 3 months after implantation, and degenerative changes were also observed after 6 months. Gore-Tex should be carefully trimmed for use in augmentation because of its potential to decrease in size over time. Additional studies are necessary before these results can be applied in clinical practice.

Molecular Events Underlying Coordinated Hormone Action in Submergence Escape Response of Deepwater Rice

Recent studies revealed that some rice varieties adopt opposite strategies to overcome flooding stress. While certain varieties hold metabolism and stay stunted until floodwater recedes, deepwater rice varieties undergo rapid stem elongation and do not suffer drowning problems. Both varieties use the same signaling agents, the ethylene response factors, as key factors even though they display opposite submergence responses. In deepwater rice, ethylene response factor genes SNORKEL1 and SNORKEL2 are believed to play a major role in submergence escape by mediating ethylene signaling, which leads to rapid stem elongation. These genes connect hormone signaling cascades from ethylene to ABA and gibberellins (GAs). Submergence increases ethylene levels in the internodal space, ethylene upregulates an ABA inactivating enzyme gene, OsCYP707A5 or OsABA8ox1, and some GA metabolism genes such as OsGA20ox genes and OsGA3ox genes. As a result of gene regulation by ethylene, internodal ABA levels decrease while GA levels increase, finally upregulating growth-related genes like expansin genes (OsEXPs). Along with the ethylene signaling in submergence, it is necessary to consider an alternative signaling pathway induced by hypoxia. Taken together, study on the submergence responses of rice plants will lead to improvement of crop production and contribution to basic research on plant growth.