Injectable ionic hydrogel conductors: Advancing material design to transform cardiac pacing.

Direct pacing of the mid myocardium where re-entry originates can be used to prevent ventricular arrhythmias and circumvent the need for painful defibrillation or cardiac ablation. However, there are no pacing electrodes small enough to navigate the coronary veins that cross these culprit scar regions. To address this need, we have developed an injectable ionically conductive hydrogel electrode that can fill the epicardial coronary veins and transform them into flexible electrodes.

Polycaprolactone-based shape memory foams as self-fitting vaginal stents.

There is an urgent critical need for a patient-forward vaginal stent that can prevent debilitating vaginal stenosis that occurs after pelvic radiation treatments and vaginal reconstruction. To this end, we developed a self-fitting vaginal stent based on a shape-memory polymer (SMP) foam that can assume a secondary, compressed shape for ease of deployment. Upon insertion, the change in temperature and hydration initiates foam expansion to shape fit to the individual patient and restore the lumen of the stent to allow egress of vaginal secretions.

Uncovering natural variation in root system architecture and growth dynamics using a robotics-assisted phenomics platform.

The plant kingdom contains a stunning array of complex morphologies easily observed above-ground, but more challenging to visualize below-ground. Understanding the magnitude of diversity in root distribution within the soil, termed root system architecture (RSA), is fundamental in determining how this trait contributes to species adaptation in local environments. Roots are the interface between the soil environment and the shoot system and therefore play a key role in anchorage, resource uptake, and stress resilience.

GRANAR, a Computational Tool to Better Understand the Functional Importance of Monocotyledon Root Anatomy.

Root hydraulic conductivity is a limiting factor along the water pathways between the soil and the leaf, and root radial conductivity is itself defined by cell-scale hydraulic properties and anatomical features. However, quantifying the influence of anatomical features on the radial conductivity remains challenging due to complex time-consuming experimental procedures. We present an open-source computational tool, the Generator of Root Anatomy in R (GRANAR; http://granar.

Cytokinin functions as an asymmetric and anti-gravitropic signal in lateral roots.

Directional organ growth allows the plant root system to strategically cover its surroundings. Intercellular auxin transport is aligned with the gravity vector in the primary root tips, facilitating downward organ bending at the lower root flank. Here we show that cytokinin signaling functions as a lateral root specific anti-gravitropic component, promoting the radial distribution of the root system.

Understanding and engineering plant form.

A plant's form is an important determinant of its fitness and economic value. Here, we review strategies for producing plants with altered forms. Historically, the process of changing a plant's form has been slow in agriculture, requiring iterative rounds of growth and selection.

GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems.

Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability.

FASCIATED EAR4 encodes a bZIP transcription factor that regulates shoot meristem size in maize.

Plant architecture is dictated by precise control of meristematic activity. In the shoot, an imbalance in positive or negative maintenance signals can result in a fasciated or enlarged meristem phenotype. fasciated ear4 (fea4) is a semidwarfed mutant with fasciated ears and tassels as well as greatly enlarged vegetative and inflorescence meristems.

Comparative analyses of C₄ and C₃ photosynthesis in developing leaves of maize and rice.

C₄ and C₃ photosynthesis differ in the efficiency with which they consume water and nitrogen. Engineering traits of the more efficient C₄ photosynthesis into C₃ crops could substantially increase crop yields in hot, arid conditions. To identify differences between C₄ and C₃ photosynthetic mechanisms, we profiled metabolites and gene expression in the developing leaves of Zea mays (maize), a C₄ plant, and Oryza sativa (rice), a C₃ plant, using a statistical method named the unified developmental model (UDM).

The cortical cytoskeletal network and cell-wall dynamics in the unicellular charophycean green alga Penium margaritaceum.

Background And Aims: Penium margaritaceum is a unicellular charophycean green alga with a unique bi-directional polar expansion mechanism that occurs at the central isthmus zone prior to cell division. This entails the focused deposition of cell-wall polymers coordinated by the activities of components of the endomembrane system and cytoskeletal networks. The goal of this study was to elucidate the structural organization of the cortical cytoskeletal network during the cell cycle and identify its specific functional roles during key cell-wall developmental events: pre-division expansion and cell division.

Polar Expansion Dynamics in the Plant Kingdom: A Diverse and Multifunctional Journey on the Path to Pollen Tubes.

Polar expansion is a widespread phenomenon in plants spanning all taxonomic groups from the Charophycean Green Algae to pollen tubes in Angiosperms and Gymnosperms. Current data strongly suggests that many common features are shared amongst cells displaying polar growth mechanics including changes to the structural features of localized regions of the cell wall, mobilization of targeted secretion mechanisms, employment of the actin cytoskeleton for directing secretion and in many cases, endocytosis and coordinated interaction of multiple signal transduction mechanisms prompted by external biotic and abiotic cues. The products of polar expansion perform diverse functions including delivery of male gametes to the egg, absorption, anchorage, adhesion and photo-absorption efficacy.

Investigation of Four Classes of Non-nodulating White Sweetclover (Melilotus alba annua Desr.) Mutants and Their Responses to Arbuscular-Mycorrhizal Fungi.

The nitrogen-fixing symbiosis between Rhizobiaceae and legumes is one of the best-studied interactions established between prokaryotes and eukaryotes. The plant develops root nodules in which the bacteria are housed, and atmospheric nitrogen is fixed into ammonia by the rhizobia and made available to the plant in exchange for carbon compounds. It has been hypothesized that this symbiosis evolved from the more ancient arbuscular mycorrhizal (AM) symbiosis, in which the fungus associates with roots and aids the plant in the absorption of mineral nutrients, particularly phosphate.

The pea early nodulin gene PsENOD7 maps in the region of linkage group I containing sym2 and leghaemoglobin.

The early nodulin gene, PsENOD7, is expressed in pea root nodules induced by Rhizobium leguminosarum bv. viciae, but not in other plant organs. In situ hybridization showed that this gene is transcribed during nodule maturation in the infected cells of the proximal part of the prefixation zone II.

Chromosomal location of lectin genes indicates they are not the basis of Rhizobium strain specificity mutations identified in pea (Pisum sativum L.).

A lectin gene family is located on linkage group 7 in pea. The lectin genes are arranged as a cluster, with no recombination observed within the multigene family. A lectin-like cDNA clone, pEA207, and eight DNA fragments generated by random priming also were mapped in the region of the lectin genes.

Exogenous Ethylene Inhibits Nodulation of Pisum sativum L. cv Sparkle.

Exogenous ethylene inhibited nodulation on the primary and lateral roots of pea, Pisum sativum L. cv Sparkle. Ethylene was more inhibitory to nodule formation than to root growth; nodule number was reduced by half with only 0.

Ethylene as a Possible Mediator of Light- and Nitrate-Induced Inhibition of Nodulation of Pisum sativum L. cv Sparkle.

Exposure of pea (Pisum sativum L. cv Sparkle) roots to light suppressed nodulation and induced an increase in ethylene production by roots. Dim light did not affect the number of infections per centimeter of root on the primary root, but most infections were blocked when the infection thread was in the epidermis or in the outer cortex.

Pleiotropic Effects of sym-17 : A Mutation in Pisum sativum L. cv Sparkle Causes Decreased Nodulation, Altered Root and Shoot Growth, and Increased Ethylene Production.

R82 (sym-17), a stable mutant of Pisum sativum L. cv Sparkle, is described. The shoot growth of the mutant was less than that of its parent under light or dark growth conditions.

Ethylene Inhibitors Partly Restore Nodulation to Pea Mutant E 107 (brz).

E107 (brz) is a pleiotropic mutant of pea (Pisum sativum L. cv Sparkle) characterized by low nodulation, leaf necrosis, excessive ion accumulation, and decreased plant size. The defective nodulation of E107 was studied by light microscopy of lateral roots.

Light Microscopy Study of Nodule Initiation in Pisum sativum L. cv Sparkle and in Its Low-Nodulating Mutant E2 (sym 5).

We compared nodule initiation in lateral roots of Pisum sativum (L.) cv Sparkle and in a low-nodulating mutant E2 (sym 5). In Sparkle, about 25% of the infections terminated in the epidermis, a similar number stopped in the cortex, and 50% resulted in the formation of a nodule meristem or an emerged nodule.

Ethylene Inhibitors Restore Nodulation to sym 5 Mutants of Pisum sativum L. cv Sparkle.

The sym 5 mutants of pea, Pisum sativum L. cv Sparkle, do not differ in growth habit from their normal parent and nodulate poorly at a root temperature of 20 degrees C. If inhibitors of ethylene formation or action (Co(2+), aminoethoxyvinylglycine, or Ag(+)) are added to the substrate, nodulation of the sym 5 mutants is increased.

sym 13-A Gene Conditioning Ineffective Nodulation in Pisum sativum.

Treatment of Pisum sativum (L.) cv. ;Sparkle' with ethyl methanesulfonic acid (EMS) produced a stable mutant, E135F, which forms small, white, ineffective nodules.

Physiological Characteristics of Fe Accumulation in the ;Bronze' Mutant of Pisum sativum L., cv ;Sparkle' E107 (brz brz).

The pea (Pisum sativum L.) mutant, E107 (brz, brz) accumulated extremely high concentrations of Fe in its older leaves when grown in light rooms in either defined nutrient media or potting mix, or outdoors in soil. Leaf symptoms (bronze color and necrosis) were correlated with very high Fe concentrations.

Pleiotropic Effects of brz: A Mutation in Pisum sativum (L.) cv ;Sparkle' Conditioning Decreased Nodulation and Increased Iron Uptake and Leaf Necrosis.

Treatment of Pisum sativum (L.) cv ;Sparkle' with ethylmethane sulfonic acid produced a stable mutant, E107, which forms few nodules. The mutant allele exhibits other pleiotropic properties including bronze necrotic spots on the leaflets and high accumulation of iron in the shoot.

An altered constitutive peptide in sym 5 mutants of Pisum sativum L.

Mutational analysis of Pisum sativum L. was used to search for constitutive proteins that might function in nodule formation. The sym 5 locus is a mutational hot spot, represented by seven independently derived mutant lines with decreased nodulation.

Effects of carbohydrate on the internal oxygen concentration, oxygen uptake, and nitrogenase activity in detached pea nodules.

The interaction between carbon substrates and O(2) and their effects on nitrogenase activity (C(2)H(2)) were examined in detached nodules of pea (Pisum sativum L. cv "Sparkle"). The internal O(2) concentration was estimated from the fractional oxygenation of leghemoglobin measured by reflectance spectroscopy.