Temporal dynamics of BMP/Nodal ratio drive tissue-specific gastrulation morphogenesis.

Anteroposterior (AP) elongation of the vertebrate body plan is driven by convergence and extension (C&E) gastrulation movements in both the mesoderm and neuroectoderm, but how or whether molecular regulation of C&E differs between tissues remains an open question. Using a zebrafish explant model of AP axis extension, we show that C&E of the neuroectoderm and mesoderm can be uncoupled ex vivo, and that morphogenesis of individual tissues results from distinct morphogen signaling dynamics. Using precise temporal manipulation of BMP and Nodal signaling, we identify a critical developmental window during which high or low BMP/Nodal ratios induce neuroectoderm- or mesoderm-driven C&E, respectively.

Optogenetic control of Nodal signaling patterns.

A crucial step in early embryogenesis is the establishment of spatial patterns of signaling activity. Tools to perturb morphogen signals with high resolution in space and time can help reveal how embryonic cells decode these signals to make appropriate fate decisions. Here, we present new optogenetic reagents and an experimental pipeline for creaHng designer Nodal signaling patterns in live zebrafish embryos.

Temporal dynamics of BMP/Nodal ratio drive tissue-specific gastrulation morphogenesis.

Anteroposterior (AP) elongation of the vertebrate body plan is driven by convergence and extension (C&E) gastrulation movements in both the mesoderm and neuroectoderm, but how or whether molecular regulation of C&E differs between tissues remains an open question. Using a zebrafish explant model of AP axis extension, we show that C&E of the neuroectoderm and mesoderm can be uncoupled , and that morphogenesis of individual tissues results from distinct morphogen signaling dynamics. Using precise temporal manipulation of BMP and Nodal signaling, we identify a critical developmental window during which high or low BMP/Nodal ratios induce neuroectoderm- or mesoderm-driven C&E, respectively.

recolorize: An R package for flexible colour segmentation of biological images.

Colour pattern variation provides biological information in fields ranging from disease ecology to speciation dynamics. Comparing colour pattern geometries across images requires colour segmentation, where pixels in an image are assigned to one of a set of colour classes shared by all images. Manual methods for colour segmentation are slow and subjective, while automated methods can struggle with high technical variation in aggregate image sets.

Jewel Beetle Opsin Duplication and Divergence Is the Mechanism for Diverse Spectral Sensitivities.

The evolutionary history of visual genes in Coleoptera differs from other well-studied insect orders, such as Lepidoptera and Diptera, as beetles have lost the widely conserved short-wavelength (SW) insect opsin gene that typically underpins sensitivity to blue light (∼440 nm). Duplications of the ancestral ultraviolet (UV) and long-wavelength (LW) opsins have occurred in many beetle lineages and have been proposed as an evolutionary route for expanded spectral sensitivity. The jewel beetles (Buprestidae) are a highly ecologically diverse and colorful family of beetles that use color cues for mate and host detection.

Evaluation of Hemp (Cannabis sativa) (Rosales: Cannabaceae) as an Alternative Host Plant for Polyphagous Noctuid Pests.

Hemp (Cannabis sativa L.) is a reemerging crop in the United States with increasing outdoor acreage in many states. This crop offers a potential host for polyphagous, defoliating lepidopteran pests currently present in Louisiana.

Investigating physical and mechanical properties of nest soils used by mud dauber wasps from a geotechnical engineering perspective.

The quality of nest soils has significant effects on reproductive success in mud dauber species. This study investigated the physical and mechanical properties of the nest soils used by mud daubers from a geotechnical engineering perspective. One hundred thirty-one nests of black and yellow mud daubers were collected from five locations in the south of Louisiana.

The pattern of nodal morphogen signaling is shaped by co-receptor expression.

Embryos must communicate instructions to their constituent cells over long distances. These instructions are often encoded in the concentration of signals called morphogens. In the textbook view, morphogen molecules diffuse from a localized source to form a concentration gradient, and target cells adopt fates by measuring the local morphogen concentration.

Two new species and distribution records for the genus Belokobylskij, 1987 from Costa Rica (Hymenoptera, Braconidae, Cardiochilinae).

Two new species of Belokobylskij, 1987 from Costa Rica are described: Kang, . and Kang, These are new distribution records for the genus in the Neotropical region. In addition, a key to species of the genus of Costa Rica is presented.

Surf and turf vision: Patterns and predictors of visual acuity in compound eye evolution.

Eyes have the flexibility to evolve to meet the ecological demands of their users. Relative to camera-type eyes, the fundamental limits of optical diffraction in arthropod compound eyes restrict the ability to resolve fine detail (visual acuity) to much lower degrees. We tested the capacity of several ecological factors to predict arthropod visual acuity, while simultaneously controlling for shared phylogenetic history.

, a new genus of Cardiochilinae (Hymenoptera, Braconidae), with descriptions of two new species from Malaysia and Vietnam.

For the first time in 21 years, a new genus of cardiochiline braconid wasp, Kang & Long, (type species Kang, ), is discovered and described. This genus represents the ninth genus in the Oriental region. Two new species ( Kang, and Long, ) are described and illustrated, and a key to species of the genus, with detailed images, is added.

Structural Diversity with Varying Disorder Enables the Multicolored Display in the Longhorn Beetle Sulawesiella rafaelae.

Light control through layered photonic nanostructures enables the strikingly colored displays of many beetles, birds, and butterflies. To achieve different reflected colors, natural organisms mainly rely on refractive index variations or scaling of a fixed structure design, as opposed to varying the type of structure. Here, we describe the presence of distinct coloration mechanisms in the longhorn beetle Sulawesiella rafaelae, which exhibits turquoise, yellow-green, and orange colors, each with a variable iridescence.

Stochastic antagonism between two proteins governs a bacterial cell fate switch.

Cell fate decision circuits must be variable enough for genetically identical cells to adopt a multitude of fates, yet ensure that these states are distinct, stably maintained, and coordinated with neighboring cells. A long-standing view is that this is achieved by regulatory networks involving self-stabilizing feedback loops that convert small differences into long-lived cell types. We combined regulatory mutants and in vivo reconstitution with theory for stochastic processes to show that the marquee features of a cell fate switch in -discrete states, multigenerational inheritance, and timing of commitments-can instead be explained by simple stochastic competition between two constitutively produced proteins that form an inactive complex.

Nodal patterning without Lefty inhibitory feedback is functional but fragile.

Developmental signaling pathways often activate their own inhibitors. Such inhibitory feedback has been suggested to restrict the spatial and temporal extent of signaling or mitigate signaling fluctuations, but these models are difficult to rigorously test. Here, we determine whether the ability of the mesendoderm inducer Nodal to activate its inhibitor Lefty is required for development.

Toddler signaling regulates mesodermal cell migration downstream of Nodal signaling.

Toddler/Apela/Elabela is a conserved secreted peptide that regulates mesendoderm development during zebrafish gastrulation. Two non-exclusive models have been proposed to explain Toddler function. The 'specification model' postulates that Toddler signaling enhances Nodal signaling to properly specify endoderm, whereas the 'migration model' posits that Toddler signaling regulates mesendodermal cell migration downstream of Nodal signaling.

Overcoming the loss of blue sensitivity through opsin duplication in the largest animal group, beetles.

Opsin proteins are fundamental components of animal vision whose structure largely determines the sensitivity of visual pigments to different wavelengths of light. Surprisingly little is known about opsin evolution in beetles, even though they are the most species rich animal group on Earth and exhibit considerable variation in visual system sensitivities. We reveal the patterns of opsin evolution across 62 beetle species and relatives.

Synchronous long-term oscillations in a synthetic gene circuit.

Synthetically engineered genetic circuits can perform a wide variety of tasks but are generally less accurate than natural systems. Here we revisit the first synthetic genetic oscillator, the repressilator, and modify it using principles from stochastic chemistry in single cells. Specifically, we sought to reduce error propagation and information losses, not by adding control loops, but by simply removing existing features.

A cure for the blues: opsin duplication and subfunctionalization for short-wavelength sensitivity in jewel beetles (Coleoptera: Buprestidae).

Background: Arthropods have received much attention as a model for studying opsin evolution in invertebrates. Yet, relatively few studies have investigated the diversity of opsin proteins that underlie spectral sensitivity of the visual pigments within the diverse beetles (Insecta: Coleoptera). Previous work has demonstrated that beetles appear to lack the short-wavelength-sensitive (SWS) opsin class that typically confers sensitivity to the "blue" region of the light spectrum.

Stochastic activation of a DNA damage response causes cell-to-cell mutation rate variation.

Cells rely on the precise action of proteins that detect and repair DNA damage. However, gene expression noise causes fluctuations in protein abundances that may compromise repair. For the Ada protein in Escherichia coli, which induces its own expression upon repairing DNA alkylation damage, we found that undamaged cells on average produce one Ada molecule per generation.

Stochastic Switching of Cell Fate in Microbes.

Microbes transiently differentiate into distinct, specialized cell types to generate functional diversity and cope with changing environmental conditions. Though alternate programs often entail radically different physiological and morphological states, recent single-cell studies have revealed that these crucial decisions are often left to chance. In these cases, the underlying genetic circuits leverage the intrinsic stochasticity of intracellular chemistry to drive transition between states.

Illustrated catalogue and type designations of the New Zealand Zopheridae (Coleoptera: Tenebrionoidea).

This paper provides a comprehensive catalogue of the New Zealand members of the family Zopheridae Solier (Coleoptera: Tenebrionoidea) in an effort to stabilize the nomenclature preceding extensive revisionary taxonomy within the group. A checklist of the 17 New Zealand zopherid genera and an account for each of the 189 species (by current combination) is provided. Type material for nearly all species was examined, and type specimens are designated herein (90 confirmed holotypes, 3 confirmed paratypes, 102 lectotypes, 280 paralectotypes).

Memory and modularity in cell-fate decision making.

Genetically identical cells sharing an environment can display markedly different phenotypes. It is often unclear how much of this variation derives from chance, external signals, or attempts by individual cells to exert autonomous phenotypic programs. By observing thousands of cells for hundreds of consecutive generations under constant conditions, we dissect the stochastic decision between a solitary, motile state and a chained, sessile state in Bacillus subtilis.

Microparticle and cell counting with digital microfluidic compact disc using standard CD drive.

Lab-on-chip medical diagnostics in a global health setting would greatly benefit from highly portable, cost effective and readily available devices. Digital compact disc (CD) and the corresponding detection device-CD drives-for personal computers are extremely affordable and distributable worldwide, therefore they can be immediately used in global health applications if empowered with molecular and cellular biosensing functions. Here we present a novel digital microfluidic CD device derived from conventional music or data CD and demonstrate its preliminary application of counting polystyrene microparticles and living cells in minute-volume fluidic samples.