Flexible biomimetic olfactory neurons based on organic heterojunction

Simulating the human olfactory nervous system is one of the key issues in the field of neuromorphic computing.Olfac-tory neurons interact with gas molecules,transmitting and storing odor information to the olfactory center of the brain.In order to emulate the complex functionalities of olfactory neurons,this study presents a flexible olfactory synapse transistor(OST)based on pentacene/C8-BTBT organic heterojunction.By modulating the interface between the energy bands of the organic semiconductor layers,this device demonstrates high sensitivity(ppb level)and memory function for NH3 sensing.Typi-cal synaptic behaviors triggered by NH_(3) pulses have been successfully demonstrated,such as inhibitory postsynaptic currents(IPSC),paired-pulse depression(PPD),long-term potentiation/depression(LTP/LTD),and transition from short-term depression(STD)to long-term depression(LTD).Furthermore,this device maintains stable olfactory synaptic functions even under differ-ent bending conditions,which can present new insights and possibilities for flexible synaptic systems and bio-inspired elec-tronic products.

Progress in Research on Insect Olfactory Perception of Habitat Odor Molecules

A highly sensitive olfactory system allows insects to precisely identify and position volatile compounds from different sources in their habitats,and plays a crucial role in their foraging,mating,and oviposition activities.During evolution,insects have successfully developed a large and complex olfactory system to adapt to heterogeneous environments,enabling the maintenance of inset population.A comprehensive examination of the olfactory system of insects may therefore yield novel insights into the development of innovative pest control and prevention strategies,as well as the study of olfactory mechanisms in vertebrates and even humans.This paper outlines the current state of research into the signal transduction mechanism by which insects perceive the olfactory molecules of their habitats.The aim of this review is to provide a reference point for future studies into the olfactory perception mechanism and its potential applications in pest management.

Factors that modulate olfactory dysfunction

The olfactory system is one of a few areas in the nervous system which is capable of regeneration throughout the life.Olfactory sensory neurons reside in the nasal cavity are continuously replenished with new neurons arising from stem cells.Some factors such as aging,neurodegenerative diseases,head trauma,brain tumor extraction and infection cause olfactory dysfunction which significantly influences physical wellbeing,quality of life,mental health,nutritional status,memory processes,identifying danger and is associated with increased mortality.Therefore,finding a treatment to improve olfactory dysfunction is needed.Recent research efforts in the field have shown some very promising new approaches to treat olfactory dysfunction.This review explores the current studies that have addressed therapeutic approaches to improve olfactory neuron regeneration based on cell transplantation therapy,modulation of physiological olfactory dysfunction and drug treatments.

Loss of CO_2 sensing by the olfactory system of CNGA3 knockout mice

Atmospheric CO2 can signal the presence of food, predators or environmental stress and trigger stereotypical behaviors in both vertebrates and invertebrates. Recent studies have shown that the necklace olfactory system in mice sensitively detects CO2 in the air. Olfactory CO2 neurons are believed to rely on cyclic gnanosine monophosphate （cGMP） as the key second messenger; however, the specific ion channel underlying CO2 responses remains unclear. Here we show that CO2-evoked neuronal and behavioral responses require cyclic nucleotide-gated （CNG） channels consisting of the CNGA3 subunit. Through Ca2＋-imaging, we found that CO2-triggered Ca2＋ influx was abolished in necklace olfactory sensory neurons （OSNs） of CNGA3-knockout mice. Olfactory detection tests using a Go/No-go paradigm showed that these knockout mice failed to detect 0.5% CO2. Thus, sensitive detection of atmospheric CO2 depends on the function of CNG channels consisting of the CNGA3 subunit in necklace OSNs. These data support the important role of the necklace olfactory system in CO2 sensing and extend our understanding of the signal transduction pathway mediating CO2 detection in mammals [Current Zoology 56 （6）： 793-799, 2010].

From neurogenesis to neuronal regeneration: the amphibian olfactory system as a model to visualize neuronal development in vivo

How do individual neurons develop and how are they in- tegrated into neuronal circuitry？ To answer this question is essential to understand how the nervous system develops and how it is maintained during the adult life. A neural stem cell must go through several stages of maturation, including proliferation, migration, differentiation, and integration, to become fully embedded to an existing neuronal circuit. The knowledge on this topic so far has come mainly from cell culture studies. Studying the development of individual neurons within intact neuronal networks in vivo is inherently difficult. Most neurons are generated form neural stem cells during embryonic and early postnatal development.

Glomerular organization in the antennal lobe of the oriental armyworm Mythimna separata

In insects,the number and specificity of antennal lobe glomeruli often reflect the number and diversity of expressed chemosensory genes,which are linked to its ecological niche and specific olfactory needs.The oriental armyworm,Mythimna separata,is an important and common lepidopteran pest of cereal crops.Given its reliance on the olfactory system for crucial behaviors,understanding the evolutionary potential of this system requires a thorough characterization of the anatomical structure of the primary olfactory center.Here,we systematically identified all antennal lobe glomeruli of M.separata based on synaptic antibody immunostaining and mass staining of the olfactory sensory neurons.A total of 69 glomeruli were identified in females and 65 in males,and an intuitive nomenclature based on glomerular positions was applied.Our findings uncovered some sex-specific glomeruli in this species.There were ten female-specific glomeruli and three male-specific glomeruli,except for the macroglomerular complex(MGC)units,with a notable observation that the female labial pit organ glomerulus was larger than its male counterpart.Additionally,we identified four antennal-lobe tracts(ALTs)and retrograde labeling from the calyx revealed that all glomeruli were innervated by the medial ALT projection neurons.The comparison of the olfactory system structures between M.separata and sympatric moths supports their evolutionary convergence in noctuid moths.These results collectively lay the foundation for future studies on olfactory processing in M.separata.

Neuroprotective effects of bloodletting at Jing points combined with mild induced hypothermia in acute severe traumatic brain injury

Bloodletting at Jing points has been used to treat coma in traditional Chinese medicine. Mild induced hypothermia has also been shown to have neuroprotective effects. However, the therapeutic effects of bloodletting at Jing points and mild induced hypothermia alone are limited. Therefore, we investigated whether combined treatment might have clinical effectiveness for the treatment of acute severe traumatic brain injury. Using a rat model of traumatic brain injury, combined treatment substantially alleviated cerebral edema and bloodbrain barrier dysfunction. Furthermore, neurological function was ameliorated, and cellular necrosis and the inflammatory response were lessened. These findings suggest that the combined effects of bloodletting at Jing points（20 μL, twice a day, for 2 days） and mild induced hypothermia（6 hours） are better than their individual effects alone. Their combined application may have marked neuroprotective effects in the clinical treatment of acute severe traumatic brain injury.

Response enhancement of olfactory sensory neurons-based biosensors for odorant detection

This paper presents a novel strategy for the response enhancement of olfactory sensory neurons (OSNs)-based biosensors by monitoring the enhancive responses of OSNs to odorants. An OSNs-based biosensor was developed on the basis of the light addressable potentiometric sensor (LAPS), in which rat OSNs were cultured on the surface of LAPS chip and served as sensing elements. LY294002, the specific inhibitor of phosphatidylinositol 3-kinase (PI3K), was used to enhance the responses of OSNs to odorants. The responses of OSNs to odorants with and without the treatment of LY294002 were recorded by LAPS. The results show that the enhancive effect of LY294002 was recorded efficiently by LAPS and the responses of this OSNs-LAPS hybrid biosensor were enhanced by LY294002 by about 1.5-fold. We conclude that this method can enhance the responses of OSNs-LAPS hybrid biosensors, which may provide a novel strategy for the bioelectrical signal monitor of OSNs in biosensors. It is also suggested that this strategy may be applicable to other kinds of OSNs-based biosensors for cellular activity detection, such as microelectrode array (MEA) and field effect transistor (FET).

The olfactory system of Pieris brassicae caterpllars:from receptors to glomeruli

Tolfactory system of adult lepidopterans is among the best described neuronal circuits.However,comparatively little is known about the organization of the olfactory system in the larval stage of these insects.Here,we explore the expression of olfactory receptors and the organization of olfactory sensory neurons in caterpillars of Pieris brassicae,a significant pest species in Europe and a well-studied species for its chemical ecology.To describe the larval olfactory system in this species,we first analyzed the head transcriptome of third-instar larvae(L3)and identified 16 odorant receptors(ORs)including the OR coreceptor(Orco),13 ionotropic receptors(IRs),and 8 gustatory receptors(GRs).We then quantified the expression of these 16 ORs in different life stages,using qPCR,and found that the majority of ORs had significantly higher expression in the L4 stage than in the L3 and L5 stages,indicating that the larval olfactory system is not static throughout caterpillar development.Using an Orco-specific antibody,we identified all olfactory receptor neurons(ORNs)expressing the Orco protein in L3,L4,and L5 caterpillars and found a total of 34 Orco-positive ORNs,distributed among three sensilla on the antenna.The number of Orco-positive ORNs did not differ among the three larval instars.Finally,we used retrograde axon tracing of the antennal nerve and identified a mean of 15 glomeruli in the larval antennal center(LAC),suggesting that the caterpillar olfactory system follows a similar design as the adult olfactory system,although with a lower numerical redundancy.Taken together,our results provide a detailed analysis of the larval olfactory neurons in P brassicae,highlighting both the differences as well as the commonalities with the adult olfactory system.These findings contribute to a better understanding of the development of the olfactory system in insects and its life-stage-specific adaptations.

Genes required for the functions of olfactory AWA neuron regulate the longevity of Caenorhabditis elegans in an insulin/IGF signaling-dependent fashion

Objective To investigate the interaction between the genes required for the functions of AWA olfactory neuron and insulin/IGF signaling in regulating the longevity of nematode Caenorhabditis elegans （C. elegans）. Methods The mutants that had loss-of-function mutation of the genes required for AWA, AWC, ASE, and AFD sensory neurons were employed. Lifespan, the speed of pharynx pumping, the intestinal autofluorescence, the dauer formation, and the brood size were examined. Rescue experiments were performed to confrm the role of the genes required for the functions of AWA neuron in regulating lifespan. Moreover, genetic interactions between genes required for the functions of AWA neuron and insulin/ IGF signaling were investigated. Results Mutations of odr-7, odr-2, and odr-3 genes required for the functions of AWA neuron significantly increased the mean lifespan of nematodes and slowed the accumulation of intestinal autofluorescence. Besides, these mutations were closely associated with higher pumping rates during aging. However, mutation of odr-7, odr- 2, or odr-3 did not obviously affect the brood size or the dauer formation, and the regulation of longevity by odr-7, odr-2, and odr-3 was temperature-independent. In contrast, mutations of genes required for the functions of ASE, AWC, and AFD sensory neurons did not infuence the nematode lifespan. Moreover, expression of odr-7, odr-2 and odr-3 in AWA neuron could completely or largely restore the altered lifespan in odr-7, odr-2 and odr-3 mutants. Furthermore, genetic interaction assay demonstrated that the extended lifespan in odr-7 mutant could be suppressed by daf-16 mutation and enhanced by daf- 2 or age-1 mutation, whereas mev-1 and pha-4 were not required for the long lifespan of odr-7 mutant. Conclusion The genes required for the function of AWA sensory neuron could regulate the nematode longevity in an insulin/IGF signaling-dependent fashion in C. elegans.

Functional map of the macroglomerular complex of male Helicoverpaarmigera

The mechanism of sex pheromone reception in the male cotton bollworm Helicoverpa armigera has been extensively studied because it has become an important model system for understanding insect olfaction.However,the pathways of pheromone processing from the antenna to the primary olfactory center in H.armigera have not yet been clarified.Here,the physiology and morphology of male H.armigera olfactory sensory neurons(OSNs)were studied using single sensillum recording along with anterograde filling and intracellular recording with retrograde filling.OSNs localized in type A sensilla responded to the major pheromone component cis-11-hexadecenal,and the axonal terminals projected to the cumulus(Cu)of the macroglomerular complex(MGC).The OSNs in type B sensilla respondcd to the bchavioral antagonist cis-9-tetradecenal,and the axonal terminals projected to the dorsomedial anterior(DMA)unit of the MGC.In type C sensilla,there were 2 OSNs:one that responded to cis-9-tetradecenal and cis-11-hexadecenol with the axonal terminals projecting to the DMA,and another that responded to the secondary pheromone components cis-9-hexadecenal and cis-9-tetradecenal with the axonal terminals projecting to the dorsomedial posterior(DMP)unit of the MGC.Type A and type B sensilla also housed the secondary OSNs,which were silent neurons with axonal terminals projected to the glomerulus G49 and DMP.Overall,the neural pathways that carry information on attractiveness and aversiveness in response to female pheromone components in H.armigera exhibit distinct projections to the MGC units.