Horizontal cell connectivity in the anchovy retina-a 3D electron microscopic study.

Background: Block-face scanning electron microscopy has opened a new era of connectomics research, in which it is possible to make dense reconstructions of all cells in a clipping of a neuronal network, such as the retina, resolving synaptic contacts. Anchovies, exceptionally abundant marine teleosts, have retinae with regions for triple cone-based color vision and a region with specialized cone photoreceptors, so-called polycones, made of long and short cones with axially oriented outer segment lamellae for polarization contrast vision. This modality, discovered in the 1970s, is unique in vertebrates, but the neural wiring for contrast generation in deeper retinal layers is unknown so far.

Subcellular plant carbohydrate metabolism under elevated temperature.

In many plant species, exposure to a changing environmental temperature regime induces an acclimation response that ultimately increases thermotolerance. Under elevated temperatures, membrane systems undergo remodeling to counteract destabilizing thermodynamic effects. Elevated temperature also affects photosynthesis and carbohydrate metabolism due to altered protein functions, enzyme activities, and transport across membrane systems.

Species-specific blood-brain barrier permeability in amphibians.

Background: The blood-brain barrier (BBB) is a semipermeable interface that prevents the non-selective transport into the central nervous system. It controls the delivery of macromolecules fueling the brain metabolism and the immunological surveillance. The BBB permeability is locally regulated depending on the physiological requirements, maintaining the tissue homeostasis and influencing pathological conditions.

Notch signaling mediates between two pattern-forming processes during head regeneration in .

head regeneration consists of hypostome/organizer and tentacle development, and involves Notch and Wnt/β-catenin signaling. Notch inhibition blocks hypostome/organizer regeneration, but not the appearance of the tentacle tissue. β-Catenin inhibition blocks tentacle, but not hypostome/organizer regeneration.

Coevolution of spermatozoa and spermathecae in Lonchopteridae (Diptera).

Across the species of spear-winged flies (Diptera: Lonchopteridae) there is a remarkable variation in size of the female reproductive tract, especially of the spermathecae. In this family there are two tubular spermathecae, which are divided into four morphologically and histologically distinct sections of different lengths and functions. The dimensions of the spermathecae and their individual sections were examined across 11 Lonchoptera species and related to the dimensions of the respective spermatozoa.

Bruno 1/CELF regulates splicing and cytoskeleton dynamics to ensure correct sarcomere assembly in Drosophila flight muscles.

Muscles undergo developmental transitions in gene expression and alternative splicing that are necessary to refine sarcomere structure and contractility. CUG-BP and ETR-3-like (CELF) family RNA-binding proteins are important regulators of RNA processing during myogenesis that are misregulated in diseases such as Myotonic Dystrophy Type I (DM1). Here, we report a conserved function for Bruno 1 (Bru1, Arrest), a CELF1/2 family homolog in Drosophila, during early muscle myogenesis.

Ambient sound stimulation tunes axonal conduction velocity by regulating radial growth of myelin on an individual, axon-by-axon basis.

Adaptive myelination is the emerging concept of tuning axonal conduction velocity to the activity within specific neural circuits over time. Sound processing circuits exhibit structural and functional specifications to process signals with microsecond precision: a time scale that is amenable to adjustment in length and thickness of myelin. Increasing activity of auditory axons by introducing sound-evoked responses during postnatal development enhances myelin thickness, while sensory deprivation prevents such radial growth during development.

A new look at the architecture and dynamics of the nerve net.

The nervous system is the paradigm of a 'simple nerve net'. Nerve cells in , as in many cnidarian polyps, are organized in a nerve net extending throughout the body column. This nerve net is required for control of spontaneous behavior: elimination of nerve cells leads to polyps that do not move and are incapable of capturing and ingesting prey (Campbell, 1976).

Development of myelination and axon diameter for fast and precise action potential conductance.

Axons of globular bushy cells in the cochlear nucleus convey hyper-accurate signals to the superior olivary complex, the initial site of binaural processing via comparably thick axons and the calyx of the Held synapse. Bushy cell fibers involved in hyper-accurate binaural processing of low-frequency sounds are known to have an unusual internode length-to-axon caliber ratio (L/d) correlating with higher conduction velocity and superior temporal precision of action potentials. How the L/d-ratio develops and what determines this unusual myelination pattern is unclear.

Variation of sperm size and evolution of giant spermatozoa in Lonchopteridae (Diptera).

Among species of the spear-winged flies (Lonchopteridae) there is remarkable variation in sperm size, with some species producing giant spermatozoa. With a length of 7500 μm and a width of 1.3 μm the spermatozoon of Lonchoptera fallax ranks among the largest known to date.

Deep haplotype analyses of target-site resistance locus ACCase in blackgrass enabled by pool-based amplicon sequencing.

Rapid adaptation of weeds to herbicide applications in agriculture through resistance development is a widespread phenomenon. In particular, the grass Alopecurus myosuroides is an extremely problematic weed in cereal crops with the potential to manifest resistance in only a few generations. Target-site resistances (TSRs), with their strong phenotypic response, play an important role in this rapid adaptive response.

The Hydrophilic Loop of PIN1 Auxin Efflux Carrier Harbors Hallmarks of an Intrinsically Disordered Protein.

Much of plant development depends on cell-to-cell redistribution of the plant hormone auxin, which is facilitated by the plasma membrane (PM) localized PIN FORMED (PIN) proteins. Auxin export activity, developmental roles, subcellular trafficking, and polarity of PINs have been well studied, but their structure remains elusive besides a rough outline that they contain two groups of 5 alpha-helices connected by a large hydrophilic loop (HL). Here, we focus on the PIN1 HL as we could produce it in sufficient quantities for biochemical investigations to provide insights into its secondary structure.

Revealing sound-induced motion patterns in fish hearing structures in 4D: a standing wave tube-like setup designed for high-resolution time-resolved tomography.

Modern bony fishes possess a high morphological diversity in their auditory structures and auditory capabilities. Yet, how auditory structures such as the otoliths in the inner ears and the swim bladder work together remains elusive. Gathering experimental evidence on the in situ motion of fish auditory structures while avoiding artifacts caused by surgical exposure of the structures has been challenging for decades.

Neon-green fluorescence in the desert gecko Pachydactylus rangei caused by iridophores.

Biofluorescence is widespread in the natural world, but only recently discovered in terrestrial vertebrates. Here, we report on the discovery of iridophore-based, neon-green flourescence in the gecko Pachydactylus rangei, localised to the skin around the eyes and along the flanks. The maximum emission of the fluorescence is at a wavelength of 516 nm in the green spectrum (excitation maximum 465 nm, blue) with another, smaller peak at 430 nm.

Morphology and ultrastructure of the spermatozoa of Lonchoptera lutea Panzer, 1809 (Diptera: Lonchopteridae).

Lonchoptera lutea males produce giant spermatozoa that are more than 2000 μm long and 1.4 μm wide. Unlike the typical brachyceran spermatozoon, they have a highly asymmetrical cross-section with only a single, albeit very large, mitochondrial derivative and a pair of massive accessory bodies, one of which extends throughout the entire length of the sperm tail.

COVID-19 and the case for global development.

COVID-19 accentuates the case for a global, rather than an international, development paradigm. The novel disease is a prime example of a development challenge for all countries, through the failure of public health as a global public good. The COVID-19 pandemic has highlighted the falsity of any assumption that the global North has all the expertise and solutions to tackle global challenges, and has further highlighted the need for multi-directional learning and transformation in all countries towards a more sustainable and equitable world.

Auditory chain reaction: Effects of sound pressure and particle motion on auditory structures in fishes.

Despite the diversity in fish auditory structures, it remains elusive how otolith morphology and swim bladder-inner ear (= otophysic) connections affect otolith motion and inner ear stimulation. A recent study visualized sound-induced otolith motion; but tank acoustics revealed a complex mixture of sound pressure and particle motion. To separate sound pressure and sound-induced particle motion, we constructed a transparent standing wave tube-like tank equipped with an inertial shaker at each end while using X-ray phase contrast imaging.

Hypomania and saccadic changes in Parkinson's disease: influence of D2 and D3 dopaminergic signalling.

In order to understand the influence of two dopaminergic signalling pathways, TaqIA rs1800497 (influencing striatal D2 receptor density) and rs6280 (influencing the striatal D3 dopamine-binding affinity), on saccade generation and psychiatric comorbidities in Parkinson's disease, this study aimed to investigate the association of saccadic performance in hypomanic or impulsive behaviour in parkinsonian patients; besides we questioned whether variants of D2 (A1+/A1-) and D3 (B1+/B1-) receptor polymorphism influence saccadic parameters differently, and if clinical parameters or brain connectivity changes modulate this association in the nigro-caudatal and nigro-collicular tract. Initially, patients and controls were compared regarding saccadic performance and differed in the parameter duration in memory-guided saccades (MGS) and visually guided saccades (VGS) trials ( < 0.0001) and in the MGS trial ( < 0.

Descending octopaminergic neurons modulate sensory-evoked activity of thoracic motor neurons in stick insects.

Neuromodulatory neurons located in the brain can influence activity in locomotor networks residing in the spinal cord or ventral nerve cords of invertebrates. How inputs to and outputs of neuromodulatory descending neurons affect walking activity is largely unknown. With the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and immunohistochemistry, we show that a population of dorsal unpaired median (DUM) neurons descending from the gnathal ganglion to thoracic ganglia of the stick insect contains the neuromodulatory amine octopamine.

Axonal degeneration in Parkinson's disease - Basal ganglia circuitry and D2 receptor availability.

Basal ganglia (BG) circuitry plays a crucial role in the control of movement. Degeneration of its pathways and imbalance of dopaminergic signalling goes along with movement disorders such as Parkinson's disease. In this study, we explore the interaction of degeneration in two BG pathways (the nigro-striatal and dentato-pallidal pathway) with D2 receptor signalling to elucidate an association to motor impairment and medication response.

The Fat Mass and Obesity-Associated Protein (FTO) Regulates Locomotor Responses to Novelty via D2R Medium Spiny Neurons.

Variations in the human FTO gene have been linked to obesity and altered connectivity of the dopaminergic neurocircuitry. Here, we report that fat mass and obesity-associated protein (FTO) in dopamine D2 receptor-expressing medium spiny neurons (D2 MSNs) of mice regulate the excitability of these cells and control their striatopallidal globus pallidus external (GPe) projections. Lack of FTO in D2 MSNs translates into increased locomotor activity to novelty, associated with altered timing behavior, without impairing the ability to control actions or affecting reward-driven and conditioned behavior.

Food Perception Primes Hepatic ER Homeostasis via Melanocortin-Dependent Control of mTOR Activation.

Adaptation of liver to the postprandial state requires coordinated regulation of protein synthesis and folding aligned with changes in lipid metabolism. Here we demonstrate that sensory food perception is sufficient to elicit early activation of hepatic mTOR signaling, Xbp1 splicing, increased expression of ER-stress genes, and phosphatidylcholine synthesis, which translate into a rapid morphological ER remodeling. These responses overlap with those activated during refeeding, where they are maintained and constantly increased upon nutrient supply.

Enigmatic ear stones: what we know about the functional role and evolution of fish otoliths.

Otoliths in bony fishes play an important role in the senses of balance and hearing. Otolith mass and shape are, among others, likely to be decisive factors influencing otolith motion and thus ear functioning. Yet our knowledge of how exactly these factors influence otolith motion is incomplete.

In-situ visualization of sound-induced otolith motion using hard X-ray phase contrast imaging.

Regarding the basics of ear structure-function relationships in fish, the actual motion of the solid otolith relative to the underlying sensory epithelium has rarely been investigated. Otolith motion has been characterized based on a few experimental studies and on approaches using mathematical modeling, which have yielded partially conflicting results. Those studies either predicted a simple back-and-forth motion of the otolith or a shape-dependent, more complex motion.