Differential effects on neuromuscular physiology between Sod loss-of-function mutation and paraquat-induced oxidative stress in Drosophila

Oxidative stress is thought to be a major contributor to aging processes. Here, we report differential effects on neurotransmission caused by loss-of-function mutations of Superoxide dismutase (Sod) and by paraquat (PQ) feeding in Drosophila. We demonstrated alterations in Sod mutants; the larval neuromuscular junction displayed supernumerary discharges and the adult giant-fiber escape pathway showed increased latency and poor response to repetitive high-frequency stimulation. Even though the concentrations used led to motor coordination defects and lethality, PQ feeding failed to reproduce such performance deficits in these larval and adult preparations, indicating mechanistic distinctions between genetic and pharmacological manipulation of oxidative stress.

From prototypes to first production units: blueSeis-1C Fiber Optical Gyroscope industrial solution for broadband ground motion rotation measurement at the best self-noise

<p><span>First results have been already shared about large mockup of giant Fiber-Optic Gyroscope from iXblue, having diameter as large as 1.2 meters, and the development road to reach an industrial product have been drawn.</span></p><p><span>Finally it appears that even if an improved performance is always wanted by scientists, a portable instrument remains the first criteria. Therefore blueSeis-1C is the smallest giant FOG achievable to our knowledge with only 400mm diameter. Moreover, and it has been made to allow performance tuning by the user without diameter increase.</span></p><p><span>With some delays, the first production units of blueSeis-1C are finally manufactured, and their tests results will be disclosed in this paper, including self-noise, scale factor variation in time and in temperature, bias variation in temperature, linearity, magnetic sensitivity, and transfer function.</span></p><p><span>These preliminary results will have to be confirmed soon by independent academic laboratory.</span></p>

Distinct aging-vulnerable trajectories of motor circuit functions in oxidation- and temperature-stressed Drosophila

We examined several sensory-motor processing circuits in Drosophila across the lifespan and uncovered distinctive age-resilient and age-vulnerable trajectories in their established functional properties. We observed relatively little deterioration toward the end of lifespan in the giant-fiber (GF) and downstream circuit elements responsible for the jump-and-flight escape reflex. In contrast, we found substantial age-dependent modifications in the performance of GF inputs and other circuits driving flight motoneuron activities. Importantly, in high temperature (HT)-reared flies (29 °C), the characteristic age-dependent progression of these properties was largely maintained, albeit over a compressed time scale, lending support for the common practice of expediting Drosophila aging studies by HT rearing. We discovered shortened lifespans in Cu2+/Zn2+Superoxide Dismutase 1 (Sod) mutant flies were accompanied by alterations distinct from HT-reared flies, highlighting differential effects of oxidative vs temperature stressors. This work also establishes several age-vulnerable parameters that may serve as quantitative neurophysiological landmarks for aging in Drosophila.

Simple and low-cost amplifier system for the study of a ventral nerve action potential in earthworm

Basic Biophysics or Neurobiology courses encounter problems when starting their practices due to the complexity and high cost of the equipment. As a consequence, these experiences are replaced by simulation software, leading students to boredom and disinterest, and finally to the lack of understanding of the basic principles of the phenomenon observed. Classical nerve conduction studies for the visualization of action potentials are an example of this, being able to be developed with simple and low-cost amplification circuits, as described in this article. The system showed stability, expected amplification and high signal-to-noise ratio. The action potential of the medial giant fiber (MGF) as lateral giant fiber (LGF) in the ventral nerve cord of the earthworms Lumbricus terrestris was recorded. The experimental system has met expectations and regains practical, effective and stimulating learning for students.

A new method of recording from the giant fiber of Drosophila melanogaster shows that the strength of its auditory inputs remains constant with age

There have been relatively few studies of how central synapses age in adult Drosophila melanogaster. In this study we investigate the aging of the synaptic inputs to the Giant Fiber (GF) from the Johnston’s Organ neurons (JONs). In previously published experiments an indirect assay of this synaptic connection was used; here we describe a new, more direct assay, which allows reliable detection of the GF action potential in the neck connective, and long term recording of its responses to sound. Genetic ablation using diphtheria toxin expressed in the GF with R68A06-GAL4 was used to show that these signals indeed arose from the GF and not from other descending neurons. As before, the sound-evoked action potentials (SEPs) in the antennal nerve were recorded via an electrode inserted at the base of the antenna. We then used this technique to quantify the response of the JONs to a high frequency sound pulse, and also the strength of the JON-GF synapse, in males and female of different ages. At no age was there any significant difference between males and females, for any of the parameters measured. Sensitivity of the JONs increased between 1 d and 10 d, with the sound intensity that elicited a half-maximal SEP decreasing by 40%. This measure almost doubled by 20 d and had increased 3-fold by 50 d compared to 10 d. Thus, JONs are most responsive around the period when most matings are taking place. The strength of the JON-GF synaptic connection itself was quite variable and did not change significantly with age. As a result, the GF’s sensitivity to sound approximately followed the JONs’ sensitivity, but with greater variability.

Cephalopod Nervous System Organization

Over 700 species of cephalopods live in the Earth’s waters, occupying almost every marine zone, from the benthic deep to the open ocean to tidal waters. The greatly varied forms and charismatic behaviors of these animals have long fascinated humans. Cephalopods are short-lived, highly mobile predators with sophisticated brains that are the largest among the invertebrates. While cephalopod brains share a similar anatomical organization, the nervous systems of coleoids (octopus, squid, cuttlefish) and nautiloids all display important lineage-specific neural adaptations. The octopus brain, for example, has for its arms a well-developed tactile learning and memory system that is vestigial in, or absent from, that of other cephalopods. The unique anatomy of the squid giant fiber system enables rapid escape in the event of capture. The brain of the nautilus comprises fewer lobes than its coleoid counterparts, but contains olfactory system structures and circuits not yet identified in other cephalopods.