Synaptic structure, distribution, and circuitry in the central nervous system of the locust and related insects.

The Orthopteran central nervous system has proved a fertile substrate for combined morphological and physiological studies of identified neurons. Electron microscopy reveals two major types of synaptic contacts between nerve fibres: chemical synapses (which predominate) and electrotonic (gap) junctions. The chemical synapses are characterized by a structural asymmetry between the pre- and postsynaptic electron dense paramembranous structures. The postsynaptic paramembranous density defines the extent of a synaptic contact that varies according to synaptic type and location in single identified neurons. Synaptic bars are the most prominent presynaptic element at both monadic and dyadic (divergent) synapses. These are associated with small electron lucent synaptic vesicles in neurons that are cholinergic or glutamatergic (round vesicles) or GABAergic (pleomorphic vesicles). Dense core vesicles of different sizes are indicative of the presence of peptide or amine transmitters. Synapses are mostly found on small-diameter neuropilar branches and the number of synaptic contacts constituting a single physiological synapse ranges from a few tens to several thousand depending on the neurones involved. Some principles of synaptic circuitry can be deduced from the analysis of highly ordered brain neuropiles. With the light microscope, synaptic location can be inferred from the distribution of the presynaptic protein synapsin I. In the ventral nerve cord, identified neurons that are components of circuits subserving known behaviours, have been studied using electrophysiology in combination with light and electron microscopy and immunocytochemistry of neuroactive compounds. This has allowed the synaptic distribution of the major classes of neurone in the ventral nerve cord to be analysed within a functional context.     

Recognition,presence, and survival of locust central nervous glia in situ and in vitro

Insect glial cells serve functions for the formation, maintenance, and performance of the central nervous system in ways similar to their vertebrate counterparts. Characterization of physiological mechanisms that underlie the roles of glia in invertebrates is largely incomplete, partly due to the lack of markers that universally label all types of glia throughout all developmental stages in various species. Studies on primary cell cultures from brains of Locusta migratoria demonstrated that the absence of anti-HRP immunoreactivity, which has previously been used to identify glial cells in undissociated brains, can also serve as a reliable glial marker in vitro, but only in combination with a viability test. As cytoplasmic membranes of cultured cells are prone to degradation when they lose viability, only cells that are both anti-HRP immunonegative and viable should be regarded as glial cells, whereas the lack of anti-HRP immunoreactivity alone is not sufficient. Cell viability can be assessed by the pattern of nuclear staining with DAPI (4′,6-diamidino-2-phenylindole), a convenient, sensitive labeling method that can be used in combination with other immunocytochemical cellular markers. We determined the glia-to-neuron ratio in central brains of fourth nymphal stage of Locusta migratoria to be 1:2 both in situ and in dissociated primary cell cultures. Analysis of primary cell cultures revealed a progressive reduction of glial cells and indicated that dead cells detach from the substrate and vanish from the analysis. Such changes in the composition of cell cultures should be considered in future physiological studies on cell cultures from insect nervous systems. Microsc. Res. Tech. 2009. © 2008 Wiley-Liss, Inc.     

Positron emission tomography—a new technique for studies of the central nervous system

Positron emission tomography (PET) has become an important tool to study the central nervous system. Examples of such studies are cerebral blood flow and metabolism and determination of receptor characteristics of the brain. In the following the basic principles and the physics behind PET are given. Different aspects are discussed such as detector design, image reconstructions and data analyses. Since quantification is essential in PET, data have to be corrected for absorption, scatter and random coincidences. These corrections and their influence on image data are discussed. A review of state-of-the-art PET research of the brain is given.     

Role of the central and peripheral nervous system in the ovarian function

This review attempts to give a comprehensive overview of ovarian innervation, considering the whole nervous system and its different levels that may modify the ovarian function. The connection between the ovary and the central nervous system through the autonomic pathways, including the peripheral ganglia, is highlighted. The evidence obtained over the last years highlights the role of the superior ovarian nerve (SON) in the ovarian phenomena. Besides, the effect on the ovary of conventional neurotransmitters and others such as indolamines and peptides, which have been found in this organ, are discussed. Various reproductive diseases have been studied almost exclusively from the endocrine point of view. It is evident that a better knowledge about the role of the neural factors involved in the ovarian physiology may facilitate the understanding of some of these. A review of the concepts and an update of some experimental designs is made that permits clarifying several aspects of the relationship between the neural system and the ovary. At present, there is no doubt that the innervation of the ovary is involved in several physiological aspects of this gland function. However, the relationship of some levels of the nervous system and the ovary offer a wide avenue for future research.     

A modification of the chromic tartrate silver impregnation technique for block impregnation of the central nervous system and paraffin wax embedding

This paper describes a block silver impregnation technique for the CNS. The procedure, which is quite simple, yields highly consistent and reproducible results. After fixation during 6–10 days in 10% saline formaldehyde, 4 mm thick blocks of brain are treated with chromic anhydride and sodium potassium tartrate solution for 4 days. After this period the specimens are rinsed in 0.75% silver nitrate solution to which 8–10 drops of pyridine per 100 ml of solution have been added. This is followed by impregnation for 4 days at 37°C in silver nitrate-pyridine solution identical to that used in the previous rinsing step. The impregnated blocks are reduced during 20–26 h in 1% pyrogallol to which 6 ml commercial formaldehyde per 100 ml of solution have been added, followed by dehydration in dioxan and paraffin embedding. Sections no thicker than 30 μm are then cut for histological study. This fundamentally neurofibrillar method reveals: (a) neuronal somata and their processes; (b) synaptic structures; (c) fibre bundles; and (d) cell nuclei and nucleoli.     

Expression and distribution of S100 protein in the nervous system of the adult zebrafish (Danio rerio)

S100 proteins are EF-hand calcium-binding protein highly preserved during evolution present in both neuronal and non-neuronal tissues of the higher vertebrates. Data about the expression of S100 protein in fishes are scarce, and no data are available on zebrafish, a common model used in biology to study development but also human diseases. In this study, we have investigated the expression of S100 protein in the central nervous system of adult zebrafish using PCR, Western blot, and immunohistochemistry. The central nervous system of the adult zebrafish express S100 protein mRNA, and contain a protein of approximately 10 kDa identified as S100 protein. S100 protein immunoreactivity was detected widespread distributed in the central nervous system, labeling the cytoplasm of both neuronal and non-neuronal cells. In fact, S100 protein immunoreactivity was primarily found in glial and ependymal cells, whereas the only neurons displaying S100 immunoreactivity were the Purkinje's neurons of the cerebellar cortex and those forming the deep cerebellar nuclei. Outside the central nervous system, S100 protein immunoreactivity was observed in a subpopulation of sensory and sympathetic neurons, and it was absent from the enteric nervous system. The functional role of S100 protein in both neurons and non-neuronal cells of the zebrafish central nervous system remains to be elucidated, but present results might serve as baseline for future experimental studies using this teleost as a model.     

Age-dependent changes in the nervous and endocrine control of the thymus

The immune system, especially the thymus, undergoes age-related modifications leading to structural and functional changes in the lymphoid organs and immunocompetent cells. Nevertheless, the consequences of thymic involution in the peripheral pool of T-cells are still a matter of controversy. The control of the thymic function is very complex and involves intrathymic signals, the autonomic nervous system, and the endocrine system. Both thymocytes and thymic stromal cells express receptors for a wide range of hormones, as well as for neurotransmitters and neuropeptides, thus affecting thymocytes maturation. This review summarizes the age-dependent variations in the extrathymic components of the thymic microenvironment, i.e., vegetative nerves and hormones, and the possible effects of those changes in the immune function.     

中央空调水系统中变频控制技术的应用

针对当前中央空调系统中水泵能耗大的问题,阐述了中央空调系统的工作原理和水泵的工作特性,分析了水泵在不同调节方法下的性能变化情况,结果表明,采用变频控制的调速方法更适合于水泵的节能运行和延长使用寿命,同时提出了在冷冻水系统和冷却水系统中分别以回水温度和冷凝器出水温度为控制对象的闭环控制方式,并针对不同的冷凝器出水温度提出了水泵调速的分段控制方法,不仅方法简单、可靠,而且节能效果好。     

Neurotrophin Trk receptors in the brain of a teleost fish, Nothobranchius furzeri

Trk neurotrophin receptors are transmembrane tyrosine kinase proteins known as TrkA, TrkB, and TrkC. TrkA is the high affinity receptor for nerve growth factor, TrkB is the one for both brain-derived neurotrophic factor and neurotrophin-4, and TrkC is the preferred receptor for neurotrophin-3. In the adult mammalian brain, neurotrophins are important regulators of neuronal function and plasticity. This study is based on Nothobranchius furzeri, a teleost fish that is becoming an ideal candidate as animal model for aging studies because its life expectancy in captivity is of just 3 months. In adult N. furzeri, all three investigated neurotrophin Trk receptors were immunohistochemically detected in each brain region. TrkA positive neuronal perikarya were localized in the dorsal and ventral areas of the telencephalon and in the cortical nucleus; TrkB immunoreactivity was observed in neuronal perikarya of the dorsal and ventral areas of the telencephalon, the diffuse inferior lobe of the hypothalamus, and Purkinje cells; TrkC positive neuronal perikarya were detected in the most aboral region of the telencephalon, in the magnocellular preoptic nucleus and in few neurons dispersed in the hypothalamus. Numerous positive fibers were widely distributed throughout the brain. Radial glial cells lining the mesencephalic and rhombencephalic ventricles showed immunoreactivity to all three Trks. These findings suggest an involvement of neurotrophins in many aspects of biology of adult N. furzeri.     

Presence and distribution of FMRFamide-like immunoreactivity in the cyprid of the barnacle Balanus amphitrite (Cirripedia, Crustacea)

The presence and distribution of FMRFamide-like peptides (FLPs) in the cyprid larvae of the barnacle Balanus amphitrite were investigated using immunohistochemical methods. Barnacles are considered to be one of the most important constituents of animal fouling communities, and the cyprid stage is specialized for settlement and metamorphosis in to the sessile adult condition. FLPs immunoreactive (IR) neuronal cell bodies were detected in both the central and the peripheral nervous system. One bilateral group of neurons somata was immunodetected in the brain, and IR nerve fibers were observed in the neuropil area and optic lobes. Intense immunostaining was also observed in the frontal filament complex: frontal filament tracts leaving the optic lobes and projecting towards the compound eyes, swollen nerve endings in the frontal filament vesicles, and thin nerve endings in the external frontal filament. Thin IR nerve fibers were also present in the cement glands. Two pairs of neuronal cell bodies were immunodetected in the posterior ganglion; some of their axons appear to project to the cirri. FLPs IR neuronal cell bodies were also localized in the wall of the dilated midgut and in the narrow hindgut; their processes surround the gut wall and allow gut neurons to synapse with one another. Our data demonstrated the presence of FLPs IR substances in the barnacle cyprid. We hypothesize that these peptides act as integrators in the central nervous system, perform neuromuscular functions for thoracic limbs, trigger intestinal movements and, at the level of the frontal filament, play a neurosecretory role.     

Developmental changes in the structure and function of the central olfactory system in gregarious and solitary desert locusts

Desert locusts are guided by olfactory cues in different behavioural contexts. In order to understand the basis for the variable olfactory guided behaviour displayed by different developmental stages and by solitary and gregarious locusts, we investigated their central olfactory system with neuroanatomical and neurophysiological methods. The primary olfactory centre of the brain, the antennal lobe (AL), increases in size during development due to an increased number and size of glomeruli. These glomeruli are innervated by a constant number of projection neurons that display increased dendritic arborizations during the development of the locust. The anatomical parameters do not differ between gregarious and solitary locusts. In parallel with the observed neuroanatomical changes, neurophysiological changes in response spectra and response specificity of AL neurons were found. During development, the percentage of neurons responding specifically to aggregation pheromone components decreases, whereas an increase in both pheromone-generalists and plant-pheromone generalist neurons is observed. The percentage of neurons responding to green leaf volatiles, however, remains constant. A decrease in the number of nymph blend-specific neurons was also observed. Our data show that anatomical and physiological properties of the AL and its neurons to a large extent reflect the changes in olfactory guided behaviour during development and between phases. The majority of our results are also in accordance with findings that the number of olfactory receptor neurons increases during development, resulting in increasing convergence on AL neurons.     

Comparison of transsynaptic viral labeling of central nervous system structures from the uterine horn in virgin, pregnant, and lactating rats

Using the transneuronal viral tracing method, the central nervous system (CNS) connections of the uterine horn were studied in virgin, pregnant, and in lactating rats. The frequency of viral labeling in the brain and the distribution of virus-infected neurons from the uterine horn were compared among groups. There was a marked difference in the frequency of viral labeling in the brain stem. In virgin rats more than half of the brain stems (5 out of 9) were labeled. In contrast, in pregnant animals viral-labeled neurons were detected in only a few cases (3 out of 16) and almost each brain stem of the lactating group was labeled (12 out of 13). A similar, less marked difference was observed in the hypothalamus. The pattern of distribution of infected neurons was similar in each group. In the brain stem, the nucleus of the solitary tract, dorsal motor nucleus of the vagus, area postrema, gigantocellular and paragigantocellular nucleus, ventrolateral medulla, A5 cell group, and caudal raphe nuclei were the most frequently labeled structures. In the diencephalon, viral-infected neurons were detected primarily in the hypothalamic paraventricular nucleus. The telencephalon was devoid of infected cells. Data suggest that the CNS control of the uterine horn varies depending on reproductive status. The low frequency of brain labeling in pregnant rats may be related to the almost complete lack of sympathetic fibers in the uterus prior to parturition and the very high frequency of labeling in lactating animals to the postpartum hyperinnervation of the uterus.     

Morphology and morphometry of the reproductive system of female Saguinus midas (Linnaeus, 1758)

In this article, the reproductive system's morphology of three young animals of the species Saguinus midas, from the bauxite mine in Paragominas, is described. The specimens were fixed and preserved in a solution of 10% aqueous formaldehyde, followed by dissection, measurement of the genital organs (uterus, vagina, ovaries, and uterine tubes), and histological processing. The vulva is delimited by the labia, with a clitoris. It is lined by keratinized stratified squamous epithelium with sebaceous glands of holocrine secretion. The vagina is an elongated tube with an average length of 26 mm and diameter of 1 mm, presenting a non-keratinized squamous epithelium, disposed between the vestibule of the vagina and cervix, the latter being relatively short. The uterus is simple, has globular shape and is located in the caudal portion of the abdominal cavity, with an average length of 14 mm and average width of 7 mm. It is formed by vascular and serous layers of muscles, and undergoes a bifurcation to form two structures on the bottom of blind sac. The uterine tubes are long and convoluted with an average length of 35 mm (right) and 36 mm (left), consisting of loose connective tissue and muscle layer lined by simple ciliated columnar epithelium. The ovaries are large and ellipsoid with smooth surface. Histologically, one animal showed ovulation fosse.     

Lateral magnocellular nucleus of the anterior neostriatum (LMAN) in the zebra finch: neuronal connectivity and the emergence of sex differences in cell morphology.

The song system of birds provides a model system to study basic mechanisms of neuronal plasticity and development underlying learned behavior. Song learning and production involve discrete sets of interconnected nuclei in the avian brain. One of these nuclei, the lateral magnocellular nucleus of the anterior neostriatum (LMAN), is the output of the so-called anterior forebrain pathway known to be essential for learning and maintenance of song, both processes depending on auditory feedback. In zebra finches, only males sing and this sexually dimorphic behavior is mirrored by sexual dimorphism in neuronal structure that develops during ontogeny. Female zebra finches are not able to sing and nuclei of the song system are strongly reduced in size or even lacking, when compared to male brains. Only LMAN can be delineated as easily in females as in males. Since female zebra finches, despite being unable to sing, recognize song just as males do and form a memory for song (model acquisition) early in life, LMAN is a putative candidate for song acquisition in both sexes. Therefore, development of LMAN was studied at the cellular and ultrastructural level in both male and female zebra finches. Regressive development of dendritic spines, enlargement of neuronal cell body and nuclei size, as well as changes at the nucleolar level are events all occurring exclusively in males, when song learning progresses. The decline in synapse number and the augmentation in synaptic contact length at synapses in LMAN in males are indicative for synaptic plasticity, whereas in females synapse number and synaptic contact length remain unchanged.     

Rhyncophorus palmarum L. (Linnaeus, 1758): A morphological and histological study of the female reproductive system

Rhyncophorus palmarum (Coleoptera) is a pest of great economic importance because of the damage caused in the plants of the Palmae family. This study showed that the female reproductive system of this beetle is composed of two ovaries of the telotrophic meroistic type invariably containing two ovarioles per ovary. Each ovariole is home to about 50 oocytes at different stages of maturation. The proximal region of the ovary is rather peculiar because it houses inside it a large quantity of bacilliform structures immersed in a glycolipoprotein substance, which has never before been described in the literature. The function of these structures is still unknown. However, it is suggested that they can function as a method of neutralizing the resistance of the plant because these insects are responsible for the transmission of the red ring disease to the palm plants. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

中央空调系统的二级次最优实时控制方法及理论分析

针对空调系统运行能耗高的特点,提出了根据系统负荷变化来进行计算机寻优控制,实现节能降耗的目的。通过将具有串联型动态特性的中央空调系统分解为二级控制结构,下级子系统间用延时环节联系,子系统最优化采取串行计算,上级协调系统只需信号传递和简单计算。摒弃了上下两级迭代求解的方式,具有计算时间短,不存在收敛性问题等特点,并得到了整体系统的次最优解,同时对估计系统次最优性进行了理论分析。运行实践表明：采用该方法节能优化效果良好。     

An automated feedback system with the hybrid model of scoring and classification for solving over-segmentation problems in RNAi high content screening

Background: High content screening (HCS) via automated fluorescence microscopy is a powerful technology for generating cellular images that are rich in phenotypic information. RNA interference is a revolutionary approach for silencing gene expression and has become an important method for studying genes through RNA interference‐induced cellular phenotype analysis. The convergence of the two technologies has led to large‐scale, image‐based studies of cellular phenotypes under systematic perturbations of RNA interference. However, existing high content screening image analysis tools are inadequate to extract content regarding cell morphology from the complex images, thus they limit the potential of genome‐wide RNA interference high content screening screening for simple marker readouts. In particular, over‐segmentation is one of the persistent problems of cell segmentation; this paper describes a new method to alleviate this problem. Methods: To solve the issue of over‐segmentation, we propose a novel feedback system with a hybrid model for automated cell segmentation of images from high content screening. A Hybrid learning model is developed based on three scoring models to capture specific characteristics of over‐segmented cells. Dead nuclei are also removed through a statistical model. Results: Experimental validation showed that the proposed method had 93.7% sensitivity and 94.23% specificity. When applied to a set of images of F‐actin‐stained Drosophila cells, 91.3% of over‐segmented cells were detected and only 2.8% were under‐segmented. Conclusions: The proposed feedback system significantly reduces over‐segmentation of cell bodies caused by over‐segmented nuclei, dead nuclei, and dividing cells. This system can be used in the automated analysis system of high content screening images.