Immunohistochemical and lectin histochemical studies on the developing olfactory organs of fetal camel

Little is known about the development of the olfactory organs of camel. In this study, prenatal development and neuronal differentiation of the vomeronasal organ (VNO) and the olfactory epithelium (OE) of the one‐humped camel were studied by immunohistochemistry and lectin histochemistry. A neuronal marker, protein gene product (PGP) 9.5, but not a marker of fully differentiated olfactory receptor cells, olfactory marker protein, intensely labeled the olfactory receptor cells of the VNO and OE at 395 mm, 510 mm, and 530 mm fetal ages, indicating that the olfactory receptor cells are differentiated, but not fully matured both in the VNO and the OE. In 187 mm and 190 mm fetuses, PGP 9.5 yielded faint immunoreactive signals in the VNO, but not in the OE, although the presence of olfactory receptor cells were demonstrated in both tissues by intense WGA and LEL stainings. We conclude that the camel VNO and OE bear differentiated, but still immature receptor cells; in addition, the onset of neuronal differentiation seems to be somewhat earlier in the VNO than in the OE till half of the prenatal life. Microsc. Res. Tech. 78:613–619, 2015. © 2015 Wiley Periodicals, Inc.     

Neurotrophins and their receptors in the primary olfactory neuraxis

The primary olfactory pathway is an elegant and simple system in which to study neurogenesis and neuronal plasticity because of the simple fact that olfactory receptor neurons (ORNs) are continually generated throughout the adult lifetimes of vertebrates. Thus, neuronal birth, differentiation, survival, axon pathfinding, target recognition, synapse formation, and cell death are developmental events that can be examined in the mature olfactory epithelium (OE). Neurotrophins (nerve growth factor, brain-derived neurotrophic factor, and neurotrophin 3, and 4/5) are a family of bioactive peptides that exert their effects by interacting with high- and low-affinity receptors on the surfaces of responsive cells, and have been implicated in several stages of neuronal development throughout the central and peripheral nervous system (CNS and PNS). There has been significant interest within the olfactory community as to how these multifunctional peptides might regulate the cycle of degeneration and regeneration of olfactory receptor neurons. The focus of this review is to highlight what is known about the actions of neurotrophins in the primary olfactory pathway, and to pinpoint future directions that will enable us to further understand their role in olfactory receptor neuron development and turnover.     

Apoptosis in the mature and developing olfactory neuroepithelium

Neuronal apoptosis is important in the developmental sculpting of a normal nervous system and also in the loss of neurons caused by neurodegenerative disease, ischemia or trauma. In a developing embryo, exquisite mechanisms of regulation exist to balance factors that control neuronal birth and death within a given neuronal group, so that sufficient neurons develop and survive to elicit normal function. Postnatally, the only part of the mammalian nervous system where many of these regulatory balance mechanisms are retained is the olfactory epithelium (OE). During the last 30 years, researchers investigating olfactory receptor neuron cellular and developmental biology have focussed on the regeneration of the neuronal population within the olfactory neuroepithelium, following the induced death of the mature neuronal population. This body of work has thus far overshadowed the equally important and intrinsically linked phenomenon of the death of mature olfactory receptor neurons, which is required to initiate regeneration. The purpose of this review is to reveal what has been established about the different forms of cell death that can occur in neurons of the olfactory epithelium, and highlight the identified pro- and anti-apoptotic pathways that control the normal and induced turnover of olfactory receptor neurons.     

Ciliated and microvillar receptor cells degenerate and then differentiate in the olfactory epithelium of rainbow trout following olfactory nerve section.

We used scanning (SEM) and transmission (TEM) electron microscopy to examine ultrastructural changes in the olfactory epithelium (OE) of rainbow trout following unilateral olfactory nerve section. Both ciliated receptor cells (CRC) and microvillar receptor cells (MRC) degenerated and subsequently differentiated from unidentified precursor cells. The following changes took place in fish that were held at 10 degrees C at the stated period following olfactory nerve section: on day 7, MRC and CRC contained intracellular vacuoles; on day 12, the olfactory knobs appeared disrupted; by day 26, olfactory receptor cells were absent from the OE; on day 42, there were receptor cell bodies and a few CRC with short cilia at the apical surface; and on day 55, a small number of both CRC and MRC had differentiated. By day 76, both CRC and MRC repopulated the OE. Degenerative changes in the cytoplasm of the sustentacular cells (SC) and ciliated nonsensory cells (CNC) were observed in the first 26 days following olfactory nerve section, but these cells remained intact throughout the experiment. The degeneration and subsequent differentiation of CRC and MRC supports and extends previous observations that both cell types are olfactory receptor neurons with axons that extend along the olfactory nerve to the olfactory bulb.     

Drosophila as a focus in olfactory research: mapping of olfactory sensilla by fine structure, odor specificity, odorant receptor expression, and central connectivity.

This review intends to integrate recent data from the Drosophila olfactory system into an up-to-date account of the neuronal basis of olfaction. It focuses on (1) an electron microscopic study that mapped a large proportion of fruitfly olfactory sensilla, (2) large-scale electrophysiological recordings that allowed the classification of the odor response spectra of a complete set of sensilla, (3) the identification and expression patterns of candidate odorant receptors in the olfactory tissues, (4) central projections of neurons expressing a given odorant receptor, (5) an improved glomerular map of the olfactory center, and (6) attempts to exploit the larval olfactory system as a model of reduced cellular complexity. These studies find surprising parallels between the olfactory systems of flies and mammals, and thus underline the usefulness of the fruitfly as an olfactory model system. Both in Drosophila and in mammals, odorant receptor neurons appear to express only one type of receptor. Neurons expressing a given receptor are scattered in the olfactory tissues but their afferents converge onto a few target glomeruli only. This suggests that in both phyla, the periphery is represented in the brain as a chemotopic map. The major difference between mammals and fruitflies refers to the numbers of receptors, neurons, and glomeruli, which are largely reduced in the latter, and particularly in larvae. Yet, if activated in a combinatorial fashion, even this small set of elements could allow discrimination between a vast array of odorants.     

Role of nerve growth factor in the olfactory system

Olfactory neurons are unique in the mammalian nervous system because of their capacity to regenerate in adult animals. It has been shown that olfactory receptor cells located in the olfactory epithelium are replaced on a continuous basis and in response to injury throughout the life span of most species. NGF, which is one of the neurotrophic factors, is present in many areas of the central and peripheral nervous system. It has been shown that NGF in the olfactory bulb plays a role in the survival of cholinergic neurons in the horizontal limb of the diagonal band (HDB). Recent studies of NGF in the olfactory bulb suggest that it is involved in the development, maintenance, and regeneration of olfactory receptor cells. In this study, we review reports examining the relationship between NGF in the olfactory bulb and neuronal regeneration and development in the mammalian olfactory systems. Low- and high-affinity NGF receptor immunoreactivity is markedly expressed during regeneration and at different stages of development in the mouse olfactory system. This level of immunoreactivity is no longer present after completion of regeneration and at maturation. Other findings indicate that NGF injected into the olfactory bulb is transported retrogradely to the olfactory epithelium. It has also been shown that continuous anti-NGF antibody injection into the olfactory bulb causes degeneration and olfactory dysfunction. Administration of NGF directory into nasal cavity results in an increase in the expression of olfactory marker protein within the olfactory epithelium in axotomized rats. These findings suggested that the presence of NGF in the olfactory bulb plays an essential role in regeneration, maintenance, and development in the olfactory system of mammals.     

<i>In vivo</i> protective effect of late embryogenesis abundant protein (ApSK₃ dehydrin) on <i>Agapanthus praecox</i> to promote post-cryopreservation survival

Dehydrins (DHNs), as members of the late embryogenesis abundant protein family, play critical roles in the protection of seeds from dehydration and plant adaptation to multiple abiotic stresses. Vitrification is a basic method in plant cryopreservation and is characterized by forming a glassy state to prevent lethal ice crystals produced during cryogenic storage. In this study, ApSK₃ type DHN was genetically transformed into embryogenic calluses (EC) of Agapanthus praecox by overexpression (OE) and RNA interference (RNAi) techniques to evaluate the in vivo protective effect of DHNs during cryopreservation. The cell viability showed a completely opposite trend in OE and RNAi cell lines, the cell relative death ratio was decreased by 20.0% in ApSK₃-OE EC and significantly increased by 66.15% in ApSK₃-RNAi cells after cryopreservation. Overexpression of ApSK₃ increased the content of non-enzymatic antioxidants (AsA and GSH) and up-regulated the expression of CAT, SOD, POD, and GPX genes, while ApSK₃-RNAi cells decreased antioxidant enzyme activities and FeSOD, POD, and APX genes expression during cryopreservation. These findings suggest that ApSK₃ affects ROS metabolism through chelating metal ions (Cu²⁺ and Fe³⁺), alleviates H₂O₂ and OH· excessive generation, activates the antioxidant system, and improves cellular REDOX balance and membrane lipid peroxidation damage of plant cells during cryopreservation. DHNs can effectively improve cell stress tolerance and have great potential for in vivo or in vitro applications in plant cryopreservation.     

Structure of the olfactory receptor organs,their GABAergic neural pathways,and modulation of mating behavior,in the giant freshwater prawn,Macrobrachium rosenbergii

In the giant male prawn, Macrobrachium rosenbergii, the olfactory system is thought to be the main pathway for modulating sexual behavior through pheromone perception. In this report, we first used gross anatomical, histological, and SEM methods to describe the structures of the olfactory receptors (sensilla setae), their neural pathways, and possible role in modulating mating behavior. On the surfaces of antennule and antenna filaments there are four types of sensory receptors, viz single spike‐like setae, single flagellum‐like setae, multiple flagella‐like setae, and aesthetascs (ASs). The ASs, which had previously been proposed to be odor receptor setae, are found only on the short filament of lateral antennule (slAn). Each AS on the slAn connects with olfactory receptor neurons (ORNs), whose axons form an outer central antennule nerve (ocAnNv), which then connects with the olfactory neutrophil (ON) of the brain. Thus, the slAn is the major olfactory organ that conveys sensory inputs from each AS to the ON within the deutocerebrum. GABA immunoreactivity was present in ASs, neurons of ORNs, inner central antennular, lateral tegumentary nerve, ocAnNv and the ON, inferring that GABA is the likely neurotransmitter in modulating olfaction. Disruption of the slAn by ablation or covering with Vaseline, resulted in significant reduction of mating behavior, indicating that this organ is crucial for sex pheromone perception. Identification of the active pheromones and further bioassays are now being performed. Microsc. Res. Tech. 76:572–587, 2013. © 2013 Wiley Periodicals, Inc.     

Tract‐tracing study of the extrabulbar Olfactory projections in the brain of some teleosts

The extrabulbar olfactory projections (EBOP) is a collection of nerve fibers that originate from primary olfactory receptor neurons. These fibers penetrate into the brain, bypassing the olfactory bulbs (OBs). While the presence of an EBOP has been well established in teleosts, here we morphologically characterize the EBOP structure in four species each with a different morphological relationship of OB with the ventral telencephalic area. Tract‐tracing methods (carbocyanine DiI/DIA and biocytin) were used. FMRFamide immunoreactive nervus terminalis (NT) components were also visualized to define any neuroanatomical relationship between the NT and EBOP. Unilateral DiI/DiA application to the olfactory chamber stained the entire olfactory epithelium, olfactory nerve fibers, and ipsilateral olfactory bulb. Labeled primary olfactory fibers running ventromedially as extrabulbar primary olfactory projections reached various regions of the secondary prosencephalon. Only in Moenkhausia sanctaefilomenae (no olfactory peduncle) did lipophilic tracer‐labeled fibers reach the ipsilateral mesencephalon. The combination of tracing techniques and FMRFamide immunohistochemistry revealed a substantial overlap of the label along the olfactory pathways as well as in the anterior secondary prosencephalon. However, FMRFamide immunoreactivity was never colocalized in the same cellular or fiber component as visualized using tracer molecules. Our results showed a certain uniformity in the neuroanatomy and extension of EBOP in all four species, independent of the pedunculate feature of the OBs. The present study also provided additional evidence to support the view that EBOP and FMRFamide immunoreactive components of the NT are separate anatomical entities. Microsc. Res. Tech. 78:268–276, 2015. © 2015 Wiley Periodicals, Inc.     

Analytical research on intellectual control of yarning characteristics for cotton collocation and rotor spinning

This research deals with the analysis of the characteristics of cotton collocation and the quality characteristics of rotor spinning. To achieve appropriate cotton collocation, the Taguchi method was employed in the experimental design in which the cotton characteristics which were measured with a high volume instrument were used to design the experiment plan according to the relevant orthogonal array. To satisfy the requirements of the modern textile industry, a Rieter open-end (OE) machine was used in the factory to spin the rotor yarn; the yarns thus produced were then measured using an Uster Tester-3, to obtain relevant yarn characteristics. For the characteristic analysis, intellectual control theory was employed to assess the factorial analysis, and the results indicated that, using neural network training and test, the mean square error obtained from the network was below 0.1. Genetic algorithms were also applied to seek one set of optimization characteristics from among cotton quality characteristics. In this way, the cotton properties and the OE rotor yarn characteristics prediction model was structured according to the result obtained by the intellectual control system. The final yarn characteristics were determined by the known cotton collocation conditions. The cotton properties and the OE rotor yarn characteristic prediction model combine the characteristics of neural networks and genetic algorithms by using the evolve perceptron neural network as the basic framework. Compared with the application of a back propagation neural network, it possesses better prediction accuracy and faster convergence. The result indicated that this research is applicable configuring the yarn characteristic prediction model system.     

Sexual dimorphism in antennal morphology and sensilla ultrastructure of Dendrolimus tabulaeformis Tsai et Liu (Lepidoptera: Lasiocampidae)

Insects rely heavily on olfaction to locate habitat, mates, and oviposition sites, while odorant molecules and the antennal olfactory sensory cells of insects are two indispensable components of olfactory response. Our previous work identified the sex pheromones and volatile compounds derived from host plant of Dendrolimus tabulaeformis Tsai et Liu, a serious economic pest of pines in northern China. However, little is known about the olfactory system of D. tabulaeformis, especially in females. To make a better understanding of the D. tabulaeformis olfactory response, we investigated the structure, innervation, numbers, and distribution of sensilla on the antennae of male and female moth, based on scanning and transmission electron microscopy. The pinniform antennae of this moth bear five types of sensilla: trichoid (TS), basiconica (BS), styloconic (StS), and chaetica (ChS) sensilla, and belt‐type structures (BTSs). The BTSs are hollow and are not chemical sensilla. The ChSs occur on the scape. StS contain dendrite sheaths and four dendrites containing microtubules in their cores. The BS contents are continuous with that in the subsegments. The TSs were sexually dimorphic and could be divided into 12 subtypes based on dendrite number and form. TS1‐4 contained two, three, or four dendrites and were similar in both sexes. TS 5‐8 and TS 9‐12 occurred only on male and female antenna, respectively. We discussed the possible functions of these sensilla. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

Ultrastructural changes of the olfactory bulb in manganesetreated mice

The effect of manganese toxicity on the ultrastructure of the olfactory bulb was evaluated. Male albino mice were injected intraperitoneally with MnCl₂ (5 mg/Kg/day) five days per week during nine weeks. The control group received NaCl (0.9%). The olfactory bulbs of five mice from each group were processed for transmission electron microscopy after 2, 4, 6 and 9 weeks of manganese treatment. On week 2, some disorganization of the myelin sheaths was observed. After 4 weeks, degenerated neurons with dilated cisternae of rough endoplasmic reticulum and swollen mitochondria appeared. A certain degree of gliosis with a predominance of astrocytes with swollen mitochondria, disorganization of the endomembrane system, dilation of the perinuclear cisternae and irregularly shaped nuclei with abnormal chromatin distribution were observed after 6 weeks. Some glial cells showed disorganization of the Golgi apparatus. On week 9, an increase in the number of astrocytes, whose mitochondrial cristae were partially or totally erased, and a dilation of the rough endoplasmic reticulum were found. Neurons appear degenerated, with swollen mitochondria and a vacuolated, electron dense cytoplasm. These changes seem to indicate that the olfactory bulb is sensitive to the toxic effects of manganese.     

Presynaptic inhibition of olfactory receptor neurons in crustaceans

Presynaptic inhibition of transmitter release from primary sensory afferents is a common strategy for regulating sensory input to the arthropod central nervous system. In the olfactory system, presynaptic inhibition of olfactory receptor neurons has been long suspected, but until recently could not be demonstrated directly because of the difficulty in recording from the afferent nerve terminals. A preparation using the isolated but intact brain of the spiny lobster in combination with voltage-sensitive dye staining has allowed stimulus-evoked responses of olfactory receptor axons to be recorded selectively with optical imaging methods. This approach has provided the first direct physiological evidence for presynaptic inhibition of olfactory receptor neurons. As in other arthropod sensory systems, the cellular mechanism underlying presynaptic afferent inhibition appears to be a reduction of action potential amplitude in the axon terminal. In the spiny lobster, two inhibitory transmitters, GABA and histamine, can independently mediate presynaptic inhibition. GABA- and histaminergic interneurons in the lobster olfactory lobe (the target of olfactory receptor neurons) constitute dual, functionally distinct inhibitory pathways that are likely to play different roles in regulating primary olfactory input to the CNS. Presynaptic inhibition in the vertebrate olfactory system is also mediated by dual inhibitory pathways, but via a different cellular mechanism. Thus, it is possible that presynaptic inhibition of primary olfactory afferents evolved independently in vertebrates and invertebrates to fill a common, fundamental role in processing olfactory information.     

Development,growth, and plasticity in the crayfish olfactory system

Decapod crustaceans have a well-defined olfactory system characterised by a set of chemosensitive sensilla grouped together in an array (the olfactory organ) on their antennules. Olfactory receptor neurons in the olfactory organ project exclusively to, and terminate in, cone-shaped olfactory glomeruli in a discrete neuropil in the brain, the olfactory lobe. The olfactory organ appears to be the only afferent input to the olfactory lobe, making the system convenient for the study of its development and growth. The progression of development of the olfactory system is a continuum and can be traced from the first appearance of peripheral receptor cells and central stem cells through to the construction of the tracts and neuropils that constitute the adult system. Cell proliferation leading to the production of peripheral and central olfactory neurons can be observed with mitotic markers in both embryonic stages and in postembryonic growth. Cell proliferation in the olfactory system in crayfish persists throughout the lives of the animals and can be modulated by manipulating the living conditions imposed on growing animals. Large serotonergic neurons that are associated with the olfactory system may play a role in the regulation of cell proliferation.     

Quantitative fluorescent speckle microscopy: where it came from and where it is going

Fluorescent speckle microscopy (FSM) is a technology for analysing the dynamics of macromolecular assemblies. Originally, the effect of random speckle formation was discovered with microtubules. Since then, the method has been expanded to other proteins of the cytoskeleton such as f‐actin and microtubule binding proteins. Newly developed, specialized software for analysing speckle movement and photometric fluctuation in the context of polymer transport and turnover has turned FSM into a powerful method for the study of cytoskeletal dynamics in cell migration, division, morphogenesis and neuronal path finding. In all these settings, FSM serves as the quantitative readout to link molecular and genetic interventions to complete maps of the cytoskeleton dynamics and thus can be used for the systematic deciphering of molecular regulation of the cytoskeleton. Fully automated FSM assays can also be applied to live‐cell screens for toxins, chemicals, drugs and genes that affect cytoskeletal dynamics. We envision that FSM has the potential to become a core tool in automated, cell‐based molecular diagnostics in cases where variations in cytoskeletal dynamics are a sensitive signal for the state of a disease, or the activity of a molecular perturbant. In this paper, we review the origins of FSM, discuss these most recent technical developments and give a glimpse to future directions and potentials of FSM. It is written as a complement to the recent review (Waterman‐Storer & Danuser, 2002, Curr. Biol., 12, R633–R640), in which we emphasized the use of FSM in cell biological applications. Here, we focus on the technical aspects of making FSM a quantitative method.     

基于视嗅觉认知的虚拟嗅觉生成装置

研发了一种基于视嗅觉认知的虚拟嗅觉生成装置,可用于虚拟环境中视嗅觉融合认知的人机交互,该装置由机械本体及其控制系统组成,可单独或同时输出3种气味。首先,分析按压气味瓶所需的作用力,设计定量送气机构,并研制装置的机械本体;然后,依据装置的驱动部件和视嗅觉交互界面,开发基于串口通信的控制系统。初步实验结果表明,所研制的虚拟嗅觉生成装置在响应时间和控制精度等方面都能满足用户需求,可为虚拟环境提供逼真的视嗅觉感知。     

Cell and molecular biology of human olfaction

Progress in our understanding of olfactory receptor physiology has progressed greatly over the past 10 years. It has become clear that many anatomical and molecular features of the peripheral aspect of the olfactory system have remained highly conserved across diverse species. Yet, this structure is responsible for conveying a wide variety of information about the environment that is necessary to the successful location of food, mates, and avoidance of danger, and it is thus not surprising that specializations have also evolved to suit the differing needs of different species. While the basic anatomical features reflect those of other mammals, functional studies of human olfactory receptor neurons have revealed physiological features both similar to and differing from those of other mammalian species. This review presents an overview of both the anatomical and physiological data describing the cell and molecular biology of the peripheral human olfactory system and how it functions in health and disease.     

Sexual dimorphism in antennal morphology and sensilla ultrastructure of a pupal endoparasitoid Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae)

Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae), a pupal parasitoid of a great number of Lepidoptera pests, has a great potential for biological control. To investigate the olfactory system of this parasitoid, we examined the morphology and ultrastructure of the antennal sensilla of both male and female T. howardi using scanning and transmission electron microscopic techniques. Antennae of male and female T. howardi were geniculate in shape, which consisted of scape, pedicel and flagellum with 5 and 4 flagellomeres, respectively. The sexual differences were recorded in the types, structure, distribution and abundance of antennal sensilla of T. howardi. Fourteen morphologically distinct types of antennal sensilla were found on the female antennae, while seventeen on the male antennae. They were: multiporous plate sensilla (MPS1‐4), chaetica sensilla (CH1‐3), multiporous trichodea sensilla (MTS), aporous trichodea sensilla (ATS1‐5), multiporous grooved peg sensilla (MGPS), coeloconic sensilla (COS), campaniform sensilla (CAS), terminal finger‐like hairy sensilla (TFI), cuticular pore (CP), and ventral sensory plaque (VSP). MPS4, ATS (3‐5), and VSP only occurred on the male antennae, while MPS2 and MPS3 only on the female antennae. The MPSs, MTS, MGPS, TFI, and CP may function as olfactory sensilla involving in detecting odor stimuli whereas the ATSs, CHs, and CAS may serve as mechanoreceptors. COS were presumed to play a role as chemo‐, thermo‐ or hygro‐receptor. The results could facilitate future studies on the biology of olfaction in T. howardi. Microsc. Res. Tech. 79:374–384, 2016. © 2016 Wiley Periodicals, Inc.     

基于植入式脑机接口的在体生物电子鼻研究进展

气味检测在食品安全控制、环境检测、缉毒、炸药搜索等社会安全防范方面起到重要作用。哺乳动物具有异常高灵敏的嗅觉系统,能检测到空气中极其痕量的气体分子,在缉毒、搜爆、反恐等社会防范方面发挥着重要的作用。本课题组提出了一种新型的基于植入式脑机接口的在体生物电子鼻:利用哺乳动物的嗅上皮作为初级气味感受器,气味信息通过嗅球和嗅皮层修饰处理后,将植入式微电极阵列包埋于嗅球或嗅皮层记录其响应信号,通过对记录到的神经元信号进行分析解码,实现气味检测与识别。本文重点介绍了在体生物电子鼻的原理、组成结构、技术实现、应用等,最后,对该领域的发展趋势进行了展望。