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1
Lemic, Jembrek, Bažok, and Pajač Živković. "Ozone Effectiveness on Wheat Weevil Suppression: Preliminary Research." Insects 10, no. 10 (October 18, 2019): 357. http://dx.doi.org/10.3390/insects10100357.
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Insect infestations within stored product facilities are a major concern to livestock and human food industries. Insect infestations in storage systems can result in economic losses of up to 20%. Furthermore, the presence of insects and their waste and remains in grain and stored foods may pose a health risk to humans and livestock. At present, pests in commercial storage are managed by a combination of different methods ranging from cleaning and cooling to treatment of the stored material with contact insecticides or fumigation. The availability of pesticides for the treatment of grain and other stored products is decreasing owing, in some cases, to environmental and safety concerns among consumers and society, thus emphasizing the need for alternative eco-friendly pest control methods. One of the potential methods is the use of ozone. Although the mechanism of action of ozone on insects is not completely known, the insect’s respiratory system is a likely the target of this gas. The main goal of this investigation was to determine the efficacy of ozone in the suppression of adult wheat weevils Sitophilus granarius. In the experiments conducted, different durations of ozone exposure were tested. In addition to ozone toxicity, the walking response and velocity of wheat weevils were investigated. The results showed the harmful effects of ozone on these insects. In addition to mortality, ozone also had negative effects on insect speed and mobility. The efficiency of the ozone treatment increased with increasing ozone exposure of insects. The ability of ozone to reduce the walking activity and velocity of treated insects is a positive feature in pest control in storage systems, thereby reducing the possibility of insects escaping from treated objects. The results of this investigation suggest that ozone has the potential to become a realistic choice for suppressing harmful insects in storage systems for humans and livestock, either alone or as a complement to other control methods.
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Waters, James S., Wah-Keat Lee, Mark W. Westneat, and John J. Socha. "Dynamics of tracheal compression in the horned passalus beetle." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 304, no. 8 (April 15, 2013): R621—R627. http://dx.doi.org/10.1152/ajpregu.00500.2012.
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Rhythmic patterns of compression and reinflation of the thin-walled hollow tubes of the insect tracheal system have been observed in a number of insects. These movements may be important for facilitating the transport and exchange of respiratory gases, but observing and characterizing the dynamics of internal physiological systems within live insects can be challenging due to their size and exoskeleton. Using synchrotron X-ray phase-contrast imaging, we observed dynamical behavior in the tracheal system of the beetle, Odontotaenius disjunctus. Similar to observations of tracheal compression in other insects, specific regions of tracheae in the thorax of O. disjunctus exhibit rhythmic collapse and reinflation. During tracheal compression, the opposing sides of a tracheal tube converge, causing the effective diameter of the tube to decrease. However, a unique characteristic of tracheal compression in this species is that certain tracheae collapse and reinflate with a wavelike motion. In the dorsal cephalic tracheae, compression begins anteriorly and continues until the tube is uniformly flattened; reinflation takes place in the reverse direction, starting with the posterior end of the tube and continuing until the tube is fully reinflated. We report the detailed kinematics of this pattern as well as additional observations that show tracheal compression coordinated with spiracle opening and closing. These findings suggest that tracheal compression may function to drive flow within the body, facilitating internal mixing of respiratory gases and ventilation of distal regions of the tracheal system.
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Maddrell, SH. "Why are there no insects in the open sea?" Journal of Experimental Biology 201, no. 17 (September 1, 1998): 2461–64. http://dx.doi.org/10.1242/jeb.201.17.2461.
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The air-filled tracheal respiratory system of insects prevents them from diving deeply in water. It is argued that this is the major factor in preventing insects from colonizing the open sea: they cannot descend sufficiently deeply in the daytime to escape being eaten by fish.
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Sláma, Karel. "Extracardiac haemocoelic pulsations and the autonomic neuroendocrine system (coelopulse) of terrestrial insects." Terrestrial Arthropod Reviews 1, no. 1 (2008): 39–80. http://dx.doi.org/10.1163/187498308x345433.
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AbstractTerrestrial insects exhibit extracardiac pulsations (ExP) in haemocoelic pressure, similar in some respect to the human blood pressure pulse. The pulsations are produced by large intersegmental abdominal musculature (abdominal pressure pump). The dorsal vessel of insects is a relatively weak organ which is unable to pump haemolymph against an increased gradient of pressure. The weak cardiac pulsations (myogenic nature) and strong ExP (neurogenic nature) occasionally occur hand in hand during similar periods with similar, but not identical frequencies. This increases the possibility of their mutual confusion. ExP can be recorded directly from haemocoelic cavity by means of hydraulic transducers or, indirectly from the body surface by recording movements of some flexible segments. In most cases, we recorded pulsations in haemocoelic pressure indirectly by recording movements of the terminal abdominal segments in immobile pupal stages. The movements caused by ExP are generally very small and invisible, only in the μm range. However, the corresponding abdominal movements or changes in haemocoelic pressure associated with the heartbeat are 30- to 500-fold smaller, in the range of nanometers. During the past three decades we have recorded cardiac and extracardiac pulsations in haemocoelic pressure in a number of insects and ticks. Practical examples of extracardiac pulsation patterns and their distinction from the heartbeat is described here for all major groups of terrestrial insects. The results obtained with monitoring of haemocoelic pulsations have revealed that terrestrial insects and possibly other arthropods posses a brain-independent, neuroendocrine system, called coelopulse. This type of newly discovered, autonomic, cholinergic system of insects shows apparent structural and functional analogy with the parasympathetic system of vertebrate animals. It regulates a number of homeostatic physiological and developmental functions, using pulsations in haemocoelic pressure for controlling circulatory and respiratory functions. The regulatory nervous center of the coelopulse system is located within thoracic ganglia of the ventral nerve cord (in analogy with parasympathetic centers in the spinal cord). Nerve impulses are dispatched from neurons of the thoracic ganglia through connectives and abdominal ganglia into large intersegmental abdominal muscles, whose contractions cause large peaks in haemocoelic pressure. The described coelopulse system controls a number of important physiological functions. For instance: 1) ExP in haemocoelic pressure cause rapid circulatory inflow and outflow of haemolymph between thoracic and abdominal parts of the body; 2) The relatively strong pressure changes caused by ExP can vigorously move tissue and organs against each other, thus preventing occlusion of haemolymph among densely packed organs; 3) Large extracardiac peaks in haemocoelic pressure open or close passively, one-way valves or tissue fold and promote circulation of haemolymph to destinations that cannot be reached by the heartbeat, i.e. ventral perineural sinus, appendages; 4) Strong ExP in haemocoelic pressure produce rhythmic, up and down compressions of tracheal tubes and air sacs, resulting in actively regulated inspirations or expirations of air through individual spiracles, i.e. actual insect breathing; 5) ExP controlled by the coelopulse neuroendocrine system causes unidirectional ventilation of the determined spiracles during emergency hypoxia, or during enzymatically produced outbursts of CO2; 6) The coelopulse system effectively controls various homeostatic physiological functions, like respiratory water loss, water retention, isoosmosis, optimum body volume, or economic gaseous exchange; 7) ExP in haemocoelic pressure plays an important roles in execution of special developmental events, like ecdysis, oviposition or pupariation. I am convinced that knowledge of the autonomic, parasympathetic-like neuroendocrine system in terrestrial arthropods may open new avenues for comparative animal physiology and pharmacology.
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Sláma, Karel. "Regulation of Respiratory Acidemia by the Autonomic Nervous System (Coelopulse) in Insects and Ticks." Physiological Zoology 67, no. 1 (January 1994): 163–74. http://dx.doi.org/10.1086/physzool.67.1.30163840.
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Bansal, Pradeep Kumar, C. L. Nawal, Aradhana Singh, Radheyshyam Chejara, Siddharth Chouhan, and Megha Agarwal. "Neonicotinoid insecticides: an emerging cause of acute pesticide poisoning." International Journal of Advances in Medicine 6, no. 3 (May 24, 2019): 976. http://dx.doi.org/10.18203/2349-3933.ijam20192275.
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Neonicotinoids are a new class of insecticides widely applied for crop protection. Information on human exposures to neonicotinoids is limited. The most common routes of exposure were ingestion (51%), dermal (44%), and ocular (11%). These insecticides act as agonists at nicotinic acetylcholine receptors, which cause insect paralysis and death the high specificity for receptors in insects was considered to possess highly selective toxicity to insects and relative sparing of mammals. However, an increasing number of cases of acute neonicotinoid poisoning have been reported in recent years. Present study report three cases presented to us with acute neonicotinoid poisoning with different manifestations including acute myocardial infarction, central nervous system (CNS) depression, and acute kidney injury, who recovered subsequently with supportive care. A detailed literature review found that respiratory, cardiovascular and certain neurological presentations are warning signs of severe neonicotinoid intoxication. Supportive treatment and decontamination are the practical methods for the management of all neonicotinoid-poisoned patients.
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O'Brien, M. A., and P. H. Taghert. "A peritracheal neuropeptide system in insects: release of myomodulin-like peptides at ecdysis." Journal of Experimental Biology 201, no. 2 (January 15, 1998): 193–209. http://dx.doi.org/10.1242/jeb.201.2.193.
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We identified of a set of neuropeptide-expressing cells sited along the respiratory system of Drosophila melanogaster using an antibody to the molluscan neuropeptide myomodulin. The number and positions of these 'peritracheal' myomodulin (PM) cells were reminiscent of the epitracheal Inka cells in the moth Manduca sexta. These Inka cells release the peptide ecdysis-triggering hormone, which helps elicit ecdysial behavior at the molt, and we show that they are also recognized by the myomodulin (MM) antibody. In both D. melanogaster and M. sexta, the PM and Inka cells are the only MM-positive cells outside the central nervous system. In both insects, MM immunoreactivity disappears at the end of the molt. In D. melanogaster, we have monitored the PM cells throughout development using two enhancer trap lines; the PM cells persist throughout development, but at larval, pupal and adult ecdyses, they display a loss of MM immunoreactivity. This transient loss occurs at a predictable time, just prior to ecdysis. In contrast, MM-positive neurons in the central nervous system do not show these changes. The PM cells also reveal a concomitant loss of immunostaining for an enzyme contained in secretory granules. The results are consistent with the hypothesis that the PM cells release MM-like peptides just prior to each ecdysis. In addition, we demonstrate that peritracheal cells of five widely divergent insect orders show a myomodulin phenotype. The peritracheal cell size, morphology, numbers and distribution vary in these different orders. These data suggest that peritracheal cells release MM-like peptides as part of a conserved feature of the endocrine regulation of insect ecdysis.
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Hanna, Lisa, and Aleksandar Popadić. "A hemipteran insect reveals new genetic mechanisms and evolutionary insights into tracheal system development." Proceedings of the National Academy of Sciences 117, no. 8 (February 10, 2020): 4252–61. http://dx.doi.org/10.1073/pnas.1908975117.
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The diversity in the organization of the tracheal system is one of the drivers of insect evolutionary success; however, the genetic mechanisms responsible are yet to be elucidated. Here, we highlight the advantages of utilizing hemimetabolous insects, such as the milkweed bug Oncopeltus fasciatus, in which the final adult tracheal patterning can be directly inferred by examining its blueprint in embryos. By reporting the expression patterns, functions, and Hox gene regulation of trachealess (trh), ventral veinless (vvl), and cut (ct), key genes involved in tracheal development, this study provides important insights. First, Hox genes function as activators, modifiers, and suppressors of trh expression, which in turn results in a difference between the thoracic and abdominal tracheal organization. Second, spiracle morphogenesis requires the input of both trh and ct, where ct is positively regulated by trh. As Hox genes regulate trh, we can now mechanistically explain the previous observations of their effects on spiracle formation. Third, the default state of vvl expression in the thorax, in the absence of Hox gene expression, features three lateral cell clusters connected to ducts. Fourth, the exocrine scent glands express vvl and are regulated by Hox genes. These results extend previous findings [Sánchez-Higueras et al., 2014], suggesting that the exocrine glands, similar to the endocrine, develop from the same primordia that give rise to the trachea. The presence of such versatile primordia in the miracrustacean ancestor could account for the similar gene networks found in the glandular and respiratory organs of both insects and crustaceans.
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Omelina, E. S., E. M. Baricheva, and E. V. Fedorova. "Main types of respiratory system structure of eggshells in insects and genes participating in their development." Biology Bulletin Reviews 3, no. 1 (January 2013): 98–107. http://dx.doi.org/10.1134/s2079086413010076.
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Trimmer, Barry A., June Aprille, and Josephine Modica-Napolitano. "Nitric oxide signalling: insect brains and photocytes." Biochemical Society Symposia 71 (March 1, 2004): 65–83. http://dx.doi.org/10.1042/bss0710065.
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The success of insects arises partly from extraordinary biochemical and physiological specializations. For example, most species lack glutathione peroxidase, glutathione reductase and respiratory-gas transport proteins and thus allow oxygen to diffuse directly into cells. To counter the increased potential for oxidative damage, insect tissues rely on the indirect protection of the thioredoxin reductase pathway to maintain redox homoeostasis. Such specializations must impact on the control of reactive oxygen species and free radicals such as the signalling molecule NO. This chapter focuses on NO signalling in the insect central nervous system and in the light-producing lantern of the firefly. It is shown that neural NO production is coupled to both muscarinic and nicotinic acetylcholine receptors. The NO-mediated increase in cGMP evokes changes in spike activity of neurons controlling the gut and body wall musculature. In addition, maps of NO-producing and -responsive neurons make insects useful models for establishing the range and specificity of NO's actions in the central nervous system. The firefly lantern also provides insight into the interplay of tissue anatomy and cellular biochemistry in NO signalling. In the lantern, nitric oxide synthase is expressed in tracheal end cells that are interposed between neuron terminals and photocytes. Exogenous NO can activate light production and NO scavengers block evoked flashes. NO inhibits respiration in isolated lantern mitochondria and this can be reversed by bright light. It is proposed that NO controls flashes by transiently inhibiting oxygen consumption and permitting direct oxidation of activated luciferin. It is possible that light production itself contributes to the restoration of mitochondrial activity and consequent cessation of the flash.
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Jang, Seonghan, Peter Mergaert, Tsubasa Ohbayashi, Kota Ishigami, Shuji Shigenobu, Hideomi Itoh, and Yoshitomo Kikuchi. "Dual oxidase enables insect gut symbiosis by mediating respiratory network formation." Proceedings of the National Academy of Sciences 118, no. 10 (March 1, 2021): e2020922118. http://dx.doi.org/10.1073/pnas.2020922118.
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Most animals harbor a gut microbiota that consists of potentially pathogenic, commensal, and mutualistic microorganisms. Dual oxidase (Duox) is a well described enzyme involved in gut mucosal immunity by the production of reactive oxygen species (ROS) that antagonizes pathogenic bacteria and maintains gut homeostasis in insects. However, despite its nonspecific harmful activity on microorganisms, little is known about the role of Duox in the maintenance of mutualistic gut symbionts. Here we show that, in the bean bug Riptortus pedestris, Duox-dependent ROS did not directly contribute to epithelial immunity in the midgut in response to its mutualistic gut symbiont, Burkholderia insecticola. Instead, we found that the expression of Duox is tracheae-specific and its down-regulation by RNAi results in the loss of dityrosine cross-links in the tracheal protein matrix and a collapse of the respiratory system. We further demonstrated that the establishment of symbiosis is a strong oxygen sink triggering the formation of an extensive network of tracheae enveloping the midgut symbiotic organ as well as other organs, and that tracheal breakdown by Duox RNAi provokes a disruption of the gut symbiosis. Down-regulation of the hypoxia-responsive transcription factor Sima or the regulators of tracheae formation Trachealess and Branchless produces similar phenotypes. Thus, in addition to known roles in immunity and in the formation of dityrosine networks in diverse extracellular matrices, Duox is also a crucial enzyme for tracheal integrity, which is crucial to sustain mutualistic symbionts and gut homeostasis. We expect that this is a conserved function in insects.
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Pendar, Hodjat, Melissa C. Kenny, and John J. Socha. "Tracheal compression in pupae of the beetle Zophobas morio." Biology Letters 11, no. 6 (June 2015): 20150259. http://dx.doi.org/10.1098/rsbl.2015.0259.
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Insects that are small or exhibit low metabolic rates are considered to not require active ventilation to augment diffusive gas exchange. Some pupae with low metabolic rates exhibit abdominal pumping, a behaviour that is known to drive tracheal ventilation in the adults of many species. However, previous work on pupae suggests that abdominal pumping may serve a non-respiratory role. To study the role of abdominal pumping in pupa of the beetle Zophobas morio , we visualized tracheal dynamics with X-rays while simultaneously measuring haemolymph pressure, abdominal movement, and CO 2 emission. Pupae exhibited frequent tracheal compressions that were coincident with both abdominal pumping and pulsation of pressure in the haemolymph. However, more than 63% of abdominal pumping events occurred without any tracheal collapse and hence ventilation, suggesting that the major function of the abdominal pump is not respiratory. In addition, this study shows that the kinematics of abdominal pumping can be used to infer the status of the spiracles and internal behaviour of the tracheal system.
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HARRISON, JON F., CALVIN J. WONG, and JOHN E. PHILLIPS. "Recovery from Acute Haemolymph Acidosis in Unfed Locusts: I. Acid Transfer to the Alimentary Lumen is the Dominant Mechanism." Journal of Experimental Biology 165, no. 1 (April 1, 1992): 85–96. http://dx.doi.org/10.1242/jeb.165.1.85.
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Organismal homeostasis requires regulation of extracellular acid-base status; however, the mechanisms by which insects regulate haemolymph pH are poorly known. We evaluated the recovery of desert locusts Schistocerca gregaria Forskal from acute acid loads, initiated by HCl injections into the haemolymph (0.5 pH unit decrease). Haemolymph pH, PCO2 and [HCO3−] recovered in 8–24 h, providing the first unequivocal evidence that insects regulate extracellular pH. There were no changes in the concentrations of the primary haemolymph buffer compounds (protein, inorganic phosphate) during recovery. Within 1 h, the tracheal system effectively eliminated the carbon dioxide derived from bicarbonate buffering. During the remainder of the recovery, haemolymph PCO2 was similar to control values; there was no respiratory compensation for decreased haemolymph pH. Approximately 75 % of the acid equivalents removed from the haemolymph during the recovery process were transferred to the lumens of the crop and midgut. Transfer of acid equivalents to the alimentary lumen provides unfed locusts with a mechanism of haemolymph pH regulation that does not compromise intracellular acid-base status or increase ventilatory water loss. Note: Current address and address for communications: Department of Zoology, Arizona State University, Tempe, AZ 85287–1501, USA.
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Prete, Frederick R., Aaron E. Schirmer, Salim Patel, Christina Carrion, Greg M. Prete, Bart Van Alphen, and Gavin J. Svenson. "Rhythmic abdominal pumping movements in praying Mantises (Insecta: Mantodea)." Fragmenta Entomologica 51, no. 1 (May 31, 2019): 29–40. http://dx.doi.org/10.4081/fe.2019.332.
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We analyzed the rhythmic, cyclical dorsal-ventral abdominal pumping movements of nymphal and adult Hierodula patellifera (Audinet- Serville 1839), and adult Stagmomantis carolina (Johansson 1763), Tenodera sinensis (de Saussure 1871), Miomantis paykullii (Stål 1871), and Sphodromantis lineola (Burmeister 1838) using a combination of customized video analysis software and frame-by-frame video analyses. Despite the phylogenetic and ecological diversity of these species, we found fundamental similarities in the overall, intermittent patterns of their abdominal pumping movements. In adults of all species, intermittent bouts of abdominal pumping had median durations of 64-89 sec, and were separated by intervals with median durations of 10-25 sec. Bouts began with rhythmic upward abdominal deflections of progressively increasing amplitude and frequency which were superimposed on an overall, progressive abdominal elevation. Bouts ended with 1-4 very high amplitude, low frequency upward deflections after which the abdomen returned to its horizontal (resting) position. In H. patellifera, the overall adult pattern emerged gradually during larval development. Given the diversity of the species tested, our data suggest that intermittent abdominal pumping (which has been associated with respiratory behavior in insects) may be independent of ecological niche or acute environmental stressors in mantises. Instead, our data support the hypothesis that these apparently respiratory related, intermittent abdominal pumping movements are an emergent property of the mantis central nervous system organization.
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Park, Yoonseong, Valery Filippov, Sarjeet S. Gill, and Michael E. Adams. "Deletion of the ecdysis-triggering hormone gene leads to lethal ecdysis deficiency." Development 129, no. 2 (January 15, 2002): 493–503. http://dx.doi.org/10.1242/dev.129.2.493.
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At the end of each developmental stage, insects perform a stereotypic behavioral sequence leading to ecdysis of the old cuticle. While ecdysis-triggering hormone (ETH) is sufficient to trigger this sequence, it has remained unclear whether it is required. We show that deletion of eth, the gene encoding ETH in Drosophila, leads to lethal behavioral and physiological deficits. Null mutants (eth–) fail to inflate the new respiratory system on schedule, do not perform the ecdysis behavioral sequence, and exhibit the phenotype buttoned-up, which is characterized by incomplete ecdysis and 98% mortality at the transition from first to second larval instar. Precisely timed injection of synthetic DmETH1 restores all deficits and allows normal ecdysis to occur. These findings establish obligatory roles for eth and its gene products in initiation and regulation of the ecdysis sequence. The ETH signaling system provides an opportunity for genetic analysis of a chemically coded physiological and behavioral sequence.
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Suarez, R. K. "Oxygen and the upper limits to animal design and performance." Journal of Experimental Biology 201, no. 8 (April 1, 1998): 1065–72. http://dx.doi.org/10.1242/jeb.201.8.1065.
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Mass-specific rates of aerobic metabolism VO2/Mb) scale in inverse proportion to body mass (Mb). Thus, small hummingbirds display the highest VO2/Mb known among vertebrates. Among all animals, higher VO2/Mb values are known only in flying insects. The high body-mass-specific rates of metabolism seen in hummingbirds are made possible by high lung O2 diffusing capacities, cardiac outputs, ratios of capillary surface area to muscle fiber surface area, mitochondrial volume densities, cristae surface densities and concentrations of enzymes involved in energy metabolism. Current evidence from control analyses of O2 transport through the respiratory and cardiovascular systems and of metabolic fluxes through pathways of energy metabolism indicates shared control of maximum flux rates among multiple steps (i.e. the absence of single rate-limiting steps). This supports the suggestion that functional capacities at each step in linear pathways or processes are matched to each other, and provides an explanation for why the up-regulation of functional capacities has occurred at virtually all steps in the evolution of the smallest vertebrate homeotherms. Flying insects make use of a tracheal system for O2 transport and, like hummingbirds, possess a highly up-regulated biochemical machinery for substrate oxidation. Studies of hummingbirds and honeybees reveal closer matches between biochemical flux capacities and maximum physiological flux rates than in animals capable of lower maximum VO2/Mb. It is proposed that the upper limits to functional capacities set the upper limit to VO2/Mb. This upper limit to aerobic metabolic rate may contribute, along with other factors, towards establishing the lower limit to vertebrate homeotherm size.
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Lazar, Angela Madalina. "Understanding SARS-CoV-2 features of infectivity, aggressiveness, and transmissibility: an insect-vector theory for SARS-CoV-2 dissemination." Journal of Ideas in Health 4, Special1 (April 15, 2021): 343–47. http://dx.doi.org/10.47108/jidhealth.vol4.issspecial1.109.
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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a ribonucleic acid–based (RNA-based) lineage B β-coronavirus characterized by 10-20 times higher infectivity and transmissibility even across species than previous coronaviruses. The significant infectivity rate of SARS-CoV-2 is due to its different host cell entry mechanisms that are mainly via angiotensin-converting enzyme 2 (ACE2) receptors contrasting earlier coronaviruses that used mainly the endosomal route. Due to the widespread distribution of ACE2 receptors throughout our body, various routes of infectivity are possible, highlighting the necessity of employing multiple forms of protection besides face masks to limit inter-human transmissibility. SARS-CoV-2 exhibits other remarkable features such as the ability to escape the immune system repeated genomic mutations that make it difficult to design a vaccine to address all viral strains and form huge host cell syncytia leading to massive tissue destruction. If we accept SARS-CoV-2 primary reservoir from bats, we should investigate the routes of viral inter-species propagation. In this article, a new theory is proposed- that the dissemination of the virus from the bats to other species and humans could have been possible via an insect vector, as insects possess significant amounts of both ACE2 receptors and a disintegrin and metalloprotease 17 (ADAM-17) enzymes that are essential for virus infectivity.
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Maina, J. N. "What it takes to fly: the structural and functional respiratory refinements in birds and bats." Journal of Experimental Biology 203, no. 20 (October 15, 2000): 3045–64. http://dx.doi.org/10.1242/jeb.203.20.3045.
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In absolute terms, flight is a highly energetically expensive form of locomotion. However, with respect to its cost per unit distance covered, powered flight is a very efficient mode of transport. Birds and bats are the only extant vertebrate taxa that have achieved flight. Phylogenetically different, they independently accomplished this elite mode of locomotion by employing diverse adaptive schemes and strategies. Integration of functional and structural parameters, a transaction that resulted in certain trade-offs and compromises, was used to overcome exacting constraints. Unique morphological, physiological and biochemical properties were initiated and refined to enhance the uptake, transfer and utilization of oxygen for high aerobic capacities. In bats, exquisite pulmonary structural parameters were combined with optimal haematological ones: a thin blood-gas barrier, a large pulmonary capillary blood volume and a remarkably extensive alveolar surface area in certain species developed in a remarkably large lung. These factors were augmented by, for example, exceptionally high venous haematocrits and haemoglobin concentrations. In birds, a particularly large respiratory surface area and a remarkably thin blood-gas (tissue) barrier developed in a small, rigid lung; a highly efficient cross-current system was fabricated within the parabronchi. The development of flight in only four animal taxa (among all the animal groups that have ever evolved; i.e. insects, the now-extinct pterosaurs, birds and bats) provides evidence for the enormous biophysical and energetic constraints that have stymied volancy. Bats improved a fundamentally mammalian lung to procure the large amounts of oxygen needed for flight. The lung/air sac system of birds is not therefore a prescriptive morphology for flight: the essence of its design can be found in the evolution of the reptilian lung, the immediate progenitor stock from which birds arose. The attainment of flight is a classic paradigm of the remarkable adaptability inherent in organismal and organic biology for countering selective pressures by initiating elegant morphologies and physiologies.
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Teulier, Loïc, Jean-Michel Weber, Julie Crevier, and Charles-A. Darveau. "Proline as a fuel for insect flight: enhancing carbohydrate oxidation in hymenopterans." Proceedings of the Royal Society B: Biological Sciences 283, no. 1834 (July 13, 2016): 20160333. http://dx.doi.org/10.1098/rspb.2016.0333.
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Bees are thought to be strict users of carbohydrates as metabolic fuel for flight. Many insects, however, have the ability to oxidize the amino acid proline at a high rate, which is a unique feature of this group of animals. The presence of proline in the haemolymph of bees and in the nectar of plants led to the hypothesis that plants may produce proline as a metabolic reward for pollinators. We investigated flight muscle metabolism of hymenopteran species using high-resolution respirometry performed on permeabilized muscle fibres. The muscle fibres of the honeybee, Apis mellifera , do not have a detectable capacity to oxidize proline, as those from the migratory locust, Locusta migratoria , used here as an outgroup representative. The closely related bumblebee, Bombus impatiens , can oxidize proline alone and more than doubles its respiratory capacity when proline is combined with carbohydrate-derived substrates. A distant wasp species, Vespula vulgaris , exhibits the same metabolic phenotype as the bumblebee, suggesting that proline oxidation is common in hymenopterans. Using a combination of mitochondrial substrates and inhibitors, we further show that in B. impatiens , proline oxidation provides reducing equivalents and electrons directly to the electron transport system. Together, these findings demonstrate that some bee and wasp species can greatly enhance the oxidation of carbohydrates using proline as fuel for flight.
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Zuk, Magdalena, Katarzyna Pelc, Jakub Szperlik, Agnieszka Sawula, and Jan Szopa. "Metabolism of the Cyanogenic Glucosides in Developing Flax: Metabolic Analysis, and Expression Pattern of Genes." Metabolites 10, no. 7 (July 14, 2020): 288. http://dx.doi.org/10.3390/metabo10070288.
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Cyanogenic glucosides (CG), the monoglycosides linamarin and lotaustralin, as well as the diglucosides linustatin and neolinustatin, have been identified in flax. The roles of CG and hydrogen cyanide (HCN), specifically the product of their breakdown, differ and are understood only to a certain extent. HCN is toxic to aerobic organisms as a respiratory inhibitor and to enzymes containing heavy metals. On the other hand, CG and HCN are important factors in the plant defense system against herbivores, insects and pathogens. In this study, fluctuations in CG levels during flax growth and development (using UPLC) and the expression of genes encoding key enzymes for their metabolism (valine N-monooxygenase, linamarase, cyanoalanine nitrilase and cyanoalanine synthase) using RT-PCR were analyzed. Linola cultivar and transgenic plants characterized by increased levels of sulfur amino acids were analyzed. This enabled the demonstration of a significant relationship between the cyanide detoxification process and general metabolism. Cyanogenic glucosides are used as nitrogen-containing precursors for the synthesis of amino acids, proteins and amines. Therefore, they not only perform protective functions against herbivores but are general plant growth regulators, especially since changes in their level have been shown to be strongly correlated with significant stages of plant development.
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Shergill, J. K., R. Cammack, J. H. Chen, M. J. Fisher, S. Madden, and H. H. Rees. "EPR spectroscopic characterization of the iron-sulphur proteins and cytochrome P-450 in mitochondria from the insect Spodoptera littoralis (cotton leafworm)." Biochemical Journal 307, no. 3 (May 1, 1995): 719–28. http://dx.doi.org/10.1042/bj3070719.
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EPR spectroscopy was used to investigate the cytochrome P-450-dependent steroid hydroxylase ecdysone 20-mono-oxygenase of the cotton leafworm (Spodoptera littoralis) and the redox centres associated with membranes from the fat-body mitochondrial fraction. Intense features at g = 2.42, 2.25 and 1.92 from oxidized mitochondrial membranes have been assigned to the low-spin haem form of ferricytochrome P-450, probably of ecdysone 20-mono-oxygenase. High-spin cytochrome P-450 (substrate-bound) was tentatively assigned to a signal at g = 8.0, which was detectable from membranes as prepared. An EPR signal characteristic of a [2Fe-2S] cluster detected from the soluble mitochondrial matrix fraction has been shown to be distinct from the signals associated with mitochondrial NADH dehydrogenase and succinate dehydrogenase, and has therefore been attributed to a ferredoxin. We conclude that the S. littoralis fat-body mitochondrial electron-transport system involved in steroid 20-hydroxylation comprises both ferredoxin and cytochrome P-450 components, and thus resembles the enzyme systems of adrenocortical mitochondria. EPR signals characteristic of the respiratory chain were also observed from fat-body mitochondria and assigned to the iron-sulphur clusters associated with Complex I (Centres N1, N2), Complex II (Centres S1, S3), Complex III (the Rieske centre), and the copper centre of Complex IV, demonstrating similarities to mammalian mitochondria. The reduced membrane fraction also yielded a major resonance at g = 2.09 and 1.88 characteristic of the [4Fe-4S] cluster of electron-transferring flavoprotein: ubiquinone oxidoreductase. As the fat-body is the major metabolic organ of insects, this protein is presumably required for the beta-oxidation of fatty acids in mitochondria. High-spin haem signals in the low-field region of spectra also demonstrated that the mitochondrial fraction contains relatively high concentrations of catalase.
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Snelling, E. P., R. S. Seymour, S. Runciman, P. G. D. Matthews, and C. R. White. "Symmorphosis and the insect respiratory system: allometric variation." Journal of Experimental Biology 214, no. 19 (September 7, 2011): 3225–37. http://dx.doi.org/10.1242/jeb.058438.
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Harrison, Jon F., James S. Waters, Arianne J. Cease, John M. VandenBrooks, Viviane Callier, C. Jaco Klok, Kimberly Shaffer, and John J. Socha. "How Locusts Breathe." Physiology 28, no. 1 (January 2013): 18–27. http://dx.doi.org/10.1152/physiol.00043.2012.
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Insect tracheal-respiratory systems achieve high fluxes and great dynamic range with low energy requirements and could be important models for bioengineers interested in developing microfluidic systems. Recent advances suggest that insect cardiorespiratory systems have functional valves that permit compartmentalization with segment-specific pressures and flows and that system anatomy allows regional flows. Convection dominates over diffusion as a transport mechanism in the major tracheae, but Reynolds numbers suggest viscous effects remain important.
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Ilyichev, A. A., L. A. Orlova, S. V. Sharabrin, and L. I. Karpenko. "mRNA technology as one of the promising platforms for the SARS-CoV-2 vaccine development." Vavilov Journal of Genetics and Breeding 24, no. 7 (December 6, 2020): 802–7. http://dx.doi.org/10.18699/vj20.676.
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After the genome sequence of SARS-CoV-2 (Severe acute respiratory syndrome-related coronavirus 2) was published and the number of infected people began to increase rapidly, many global companies began to develop a vaccine. Almost all known approaches to vaccine design were applied for this purpose, including inactivated viruses, mRNA and DNA-vaccines, vaccines based on various viral vectors, synthetically generated peptides and recombinant proteins produced in cells of insects and mammals. This review considers one of the promising vaccine platforms based on messenger RNA. Until recent years, mRNA-vaccination was out of practical implementation due to high sensitivity to nuclease degradation and consequent instability of drugs based on mRNA. Latest technological advances significantly mitigated the problems of low immunogenicity, instability, and difficulties in RNA-vaccine delivery. It is worth noting that mRNA-vaccines can efficiently activate both components of the immune system, i. e. T-cell and humoral responses. The essential advantage of mRNA-vaccines includes fast, inexpensive, scalable and uniform production providing a large output of desirable products in vitro. Synthesis and purification processes significantly simplify the process technology of mRNA drugs with injectable purity. Thus, mRNA production via in vitro transcription is more advantageous as compared with DNA-vaccines since it is a chemical process without the use of cells. mRNA techniques make it possible to pass all the phases of vaccine development much faster in comparison with the production of vaccines based on inactivated viruses or recombinant proteins. This property is critically important when designing vaccines against viral pathogens as the main problem of disease control includes a time gap between an epidemic and vaccine development. This paper discusses studies on the development of vaccines against coronaviruses including SARS-CoV-2 with special attention to the mRNA technique.
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Sedláková, Veronika, Michaela Kloučková, Zuzana Garlíková, Kateřina Vašíčková, Josef Jaroš, Mário Kandra, Hana Kotasová, and Aleš Hampl. "Options for modeling the respiratory system: inserts, scaffolds and microfluidic chips." Drug Discovery Today 24, no. 4 (April 2019): 971–82. http://dx.doi.org/10.1016/j.drudis.2019.03.006.
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Loli, Denise, and José Eduardo P. W. Bicudo. "Control and Regulatory Mechanisms Associated with Thermogenesis in Flying Insects and Birds." Bioscience Reports 25, no. 3-4 (June 8, 2005): 149–80. http://dx.doi.org/10.1007/s10540-005-2883-8.
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Most insects and birds are able to fly. The chitin made exoskeleton of insects poses them several constraints, and this is one the reasons they are in general small sized animals. On the other hand, because birds possess an endoskeleton made of bones they may grow much larger when compared to insects. The two taxa are quite different with regards to their general “design” platform, in particular with respect to their respiratory and circulatory systems. However, because they fly, they may share in common several traits, namely those associated with the control and regulatory mechanisms governing thermogenesis. High core temperatures are essential for animal flight irrespective of the taxa they belong to. Birds and insects have thus evolved mechanisms which allowed them to control and regulate high rates of heat fluxes. This article discusses possible convergent thermogenic control and regulatory mechanisms associated with flight in insects and birds.
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Verberk, Wilco C. E. P., and David T. Bilton. "Respiratory control in aquatic insects dictates their vulnerability to global warming." Biology Letters 9, no. 5 (October 23, 2013): 20130473. http://dx.doi.org/10.1098/rsbl.2013.0473.
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Forecasting species responses to climatic warming requires knowledge of how temperature impacts may be exacerbated by other environmental stressors, hypoxia being a principal example in aquatic systems. Both stressors could interact directly as temperature affects both oxygen bioavailability and ectotherm oxygen demand. Insufficient oxygen has been shown to limit thermal tolerance in several aquatic ectotherms, although, the generality of this mechanism has been challenged for tracheated arthropods. Comparing species pairs spanning four different insect orders, we demonstrate that oxygen can indeed limit thermal tolerance in tracheates. Species that were poor at regulating oxygen uptake were consistently more vulnerable to the synergistic effects of warming and hypoxia, demonstrating the importance of respiratory control in setting thermal tolerance limits.
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Snelling, E. P., R. S. Seymour, S. Runciman, P. G. D. Matthews, and C. R. White. "Symmorphosis and the insect respiratory system: a comparison between flight and hopping muscle." Journal of Experimental Biology 215, no. 18 (June 26, 2012): 3324–33. http://dx.doi.org/10.1242/jeb.072975.
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Greenlee, KJ, and JF Harrison. "Acid-base and respiratory responses to hypoxia in the grasshopper Schistocerca americana." Journal of Experimental Biology 201, no. 20 (October 15, 1998): 2843–55. http://dx.doi.org/10.1242/jeb.201.20.2843.
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How do quiescent insects maintain constant rates of oxygen consumption at ambient PO2 values as low as 2-5 kPa? To address this question, we examined the response of the American locust Schistocerca americana to hypoxia by measuring the effect of decreasing ambient PO2 on haemolymph acid-base status, tracheal PCO2 and CO2 emission. We also tested the effect of hypoxia on convective ventilation using a new optical technique which measured the changes in abdominal volume during ventilation. Hypoxia caused a progressive increase in haemolymph pH and a decrease in haemolymph PCO2. A Davenport analysis suggests that hypoxia is accompanied by a net transfer of base to the haemolymph, perhaps as a result of intracellular pH regulation. Hypoxia caused a progressive increase in convective ventilation which was mostly attributable to a rise in ventilatory frequency. Carbon dioxide conductance ( micromol h-1 kPa-1) across the spiracles increased more than threefold, while conductance between the haemolymph and primary trachea nearly doubled in 2 kPa O2 relative to room air. The rise in trans-spiracular conductance is completely attributable to the elevations in convective ventilation. The rise in tracheal conductance in response to hypoxia may reflect the removal of fluid from the tracheoles described by Wigglesworth. The low critical PO2 of quiescent insects can be attributed (1) to their relatively low resting metabolic rates, (2) to the possession of tracheal systems adapted for the exchange of gases at much higher rates during activity and (3) to the ability of insects to rapidly modulate tracheal conductance.
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Ramírez, Martín J. "RESPIRATORY SYSTEM MORPHOLOGY AND THE PHYLOGENY OF HAPLOGYNE SPIDERS (ARANEAE, ARANEOMORPHAE)." Journal of Arachnology 28, no. 2 (September 2000): 149–57. http://dx.doi.org/10.1636/0161-8202(2000)028[0149:rsmatp]2.0.co;2.
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Hilken, Gero, Jörg Rosenberg, Gregory D. Edgecombe, Valentin Blüml, Jörg U. Hammel, Anja Hasenberg, and Andy Sombke. "The tracheal system of scutigeromorph centipedes and the evolution of respiratory systems of myriapods." Arthropod Structure & Development 60 (January 2021): 101006. http://dx.doi.org/10.1016/j.asd.2020.101006.
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Nassar, P. N., A. C. Jackson, and D. R. Carrier. "Entraining the natural frequencies of running and breathing in guinea fowl (Numida meleagris)." Journal of Experimental Biology 204, no. 9 (May 1, 2001): 1641–51. http://dx.doi.org/10.1242/jeb.204.9.1641.
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Lung ventilation of tetrapods that synchronize their locomotory and ventilatory cycles during exercise could be economized if the resonant frequency of the respiratory system matched the animal's preferred step frequency. To test whether animals utilize this strategy, the input impedance of the respiratory system of five anesthetized, supine guinea fowl (Numida meleagris) was measured using a forced oscillation technique. The resonant frequency of the respiratory system was 7.12+/−0.27 Hz (N=5, mean +/− S.E.M.). No statistically significant difference was found between the resonant frequency of the respiratory system and the panting frequency used by guinea fowl at rest (6.67+/−0.16 Hz, N=11) or during treadmill locomotion (6.71+/−0.12 Hz, N=8) or to their preferred step frequency (6.73+/−0.09 Hz, N=7) (means +/− S.E.M.). These observations suggest (i) that, at rest and during exercise, panting guinea fowl maximize flow while expending minimal mechanical effort, and (ii) that natural selection has tuned the natural frequencies of the respiratory and locomotor systems to similar frequencies.
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Lehmann, Philipp, Marion Javal, and John S. Terblanche. "Oxygen limitation is not the cause of death during lethal heat exposure in an insect." Biology Letters 15, no. 1 (January 2019): 20180701. http://dx.doi.org/10.1098/rsbl.2018.0701.
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Oxygen- and capacity-limited thermal tolerance (OCLTT) is a controversial hypothesis claiming to explain variation in, and mechanistically determine, animal thermal limits. The lack of support from Insecta is typically argued to be a consequence of their high-performance respiratory systems. However, no studies have reported internal body oxygen levels during thermal ramping so it is unclear if changes in ambient gas are partially or fully offset by a compensatory respiratory system. Here we provide such an assessment by simultaneously recording haemolymph oxygen (pO 2 ) levels—as an approximation of tissue oxygenation—while experimentally manipulating ambient oxygen and subjecting organisms to thermal extremes in a series of thermolimit respirometry experiments using pupae of the butterfly Pieris napi . The main results are that while P. napi undergo large changes in haemolymph pO 2 that are positively correlated with experimental oxygen levels, haemolymph pO 2 is similar pre- and post-death during thermal assays. OCLTT predicts that reduction in body oxygen level should lead to a reduction in CTmax. Despite finding the former, there was no change in CTmax across a wide range of body oxygen levels. Thus, we argue that oxygen availability is not a functional determinant of the upper thermal limits in pupae of P. napi .
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Harrison, Jon F., Khaled Adjerid, Anelia Kassi, C. Jaco Klok, John M. VandenBrooks, Meghan E. Duell, Jacob B. Campbell, et al. "Physiological responses to gravity in an insect." Proceedings of the National Academy of Sciences 117, no. 4 (January 13, 2020): 2180–86. http://dx.doi.org/10.1073/pnas.1915424117.
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Gravity is one of the most ubiquitous environmental effects on living systems: Cellular and organismal responses to gravity are of central importance to understanding the physiological function of organisms, especially eukaryotes. Gravity has been demonstrated to have strong effects on the closed cardiovascular systems of terrestrial vertebrates, with rapidly responding neural reflexes ensuring proper blood flow despite changes in posture. Invertebrates possess open circulatory systems, which could provide fewer mechanisms to restrict gravity effects on blood flow, suggesting that these species also experience effects of gravity on blood pressure and distribution. However, whether gravity affects the open circulatory systems of invertebrates is unknown, partly due to technical measurement issues associated with small body size. Here we used X-ray imaging, radio-tracing of hemolymph, and micropressure measurements in the American grasshopper, Schistocerca americana, to assess responses to body orientation. Our results show that during changes in body orientation, gravity causes large changes in blood and air distribution, and that body position affects ventilation rate. Remarkably, we also found that insects show similar heart rate responses to body position as vertebrates, and contrasting with the classic understanding of open circulatory systems, have flexible valving systems between thorax and abdomen that can separate pressures. Gravitational effects on invertebrate cardiovascular and respiratory systems are likely to be widely distributed among invertebrates and to have broad influence on morphological and physiological evolution.
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Bhargava Periwal, S., and John J. Cebra. "Respiratory Mucosal Immunization with Reovirus Serotype 1/L Stimulates Virus-Specific Humoral and Cellular Immune Responses, Including Double-Positive (CD4+/CD8+) T Cells." Journal of Virology 73, no. 9 (September 1, 1999): 7633–40. http://dx.doi.org/10.1128/jvi.73.9.7633-7640.1999.
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ABSTRACT Respiratory virus infections are a serious health challenge. A number of models that examine the nature of the respiratory immune response to particular pathogens exist. However, many pathogens that stimulate specific immunity in the lung are frequently not effective immunogens at other mucosal sites. A pathogen that is an effective respiratory as well as gastrointestinal immunogen would allow studies of the interaction between the mucosal sites. Reovirus (respiratory enteric orphan virus) serotype 1 is known to be an effective gut mucosal immunogen and provides a potential model for the relationship between the respiratory and the gut mucosal immune systems. In this study, we demonstrate that intratracheal immunization with reovirus 1/Lang (1/L) in C3H mice resulted in high titers of virus in the respiratory tract-associated lymphoid tissue (RALT). High levels of reovirus-specific immunoglobulin A were determined in the RALT fragment cultures. The major responding components of the bronchus-associated lymphoid tissue were the CD8+ T lymphocytes. Cells from draining lymph nodes also exhibited lysis of reovirus-infected target cells after an in vitro culture. The present study also describes the distribution of transiently present CD4+/CD8+double-positive (DP) T cells in the mediastinal and tracheobronchial lymph nodes of RALT. CD4+/CD8+ DP lymphocytes were able to proliferate in response to stimulation with viral antigen in culture. Furthermore, these cells exhibited lysis of reovirus-infected target cells after in vitro culture. These results establish reovirus 1/L as a viable model for future investigation of the mucosal immune response in the RALT and its relationship to the common mucosal immune system.
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Matthews, Philip G. D., Edward P. Snelling, Roger S. Seymour, and Craig R. White. "A test of the oxidative damage hypothesis for discontinuous gas exchange in the locust Locusta migratoria." Biology Letters 8, no. 4 (April 4, 2012): 682–84. http://dx.doi.org/10.1098/rsbl.2012.0137.
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The discontinuous gas exchange cycle (DGC) is a breathing pattern displayed by many insects, characterized by periodic breath-holding and intermittently low tracheal O 2 levels. It has been hypothesized that the adaptive value of DGCs is to reduce oxidative damage, with low tracheal O 2 partial pressures ( P O 2 ∼2–5 kPa) occurring to reduce the production of oxygen free radicals. If this is so, insects displaying DGCs should continue to actively defend a low tracheal P O 2 even when breathing higher than atmospheric levels of oxygen (hyperoxia). This behaviour has been observed in moth pupae exposed to ambient P O 2 up to 50 kPa. To test this observation in adult insects, we implanted fibre-optic oxygen optodes within the tracheal systems of adult migratory locusts Locusta migratoria exposed to normoxia, hypoxia and hyperoxia. In normoxic and hypoxic atmospheres, the minimum tracheal P O 2 that occurred during DGCs varied between 3.4 and 1.2 kPa. In hyperoxia up to 40.5 kPa, the minimum tracheal P O 2 achieved during a DGC exceeded 30 kPa, increasing with ambient levels. These results are consistent with a respiratory control mechanism that functions to satisfy O 2 requirements by maintaining P O 2 above a critical level, not defend against high levels of O 2 .
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Simelane, S. M., S. Abelman, and F. D. Duncan. "Dynamics of the Oxygen, Carbon Dioxide, and Water Interaction across the Insect Spiracle." Abstract and Applied Analysis 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/157573.
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This paper explores the dynamics of respiratory gases interactions which are accompanied by the loss of water through an insect’s spiracle. Here we investigate and analyze this interaction by deriving a system of ordinary differential equations for oxygen, carbon dioxide, and water vapor. The analysis is carried out in continuous time. The purpose of the research is to determine bounds for the gas volumes and to discuss the complexity and stability of the equilibria. Numerical simulations also demonstrate the dynamics of our model utilizing the new conditions for stability and instability.
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Okoroiwu, Henshaw Uchechi, and Iwara Arikpo Iwara. "Dichlorvos toxicity: A public health perspective." Interdisciplinary Toxicology 11, no. 2 (August 1, 2018): 129–37. http://dx.doi.org/10.2478/intox-2018-0009.
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Abstract Pesticides are used in agriculture and in domestic pest control. Dichlorvos, an organophosphate, is a predominant pesticide used in domestic insect control in developing countries. Acute and prolonged exposure may lead to death, genotoxic, neurological, reproductive, carcinogenic, immunological, hepatic, renal, respiratory, metabolic, dermal and other systemic effects. Its toxicity is due to the ability of the compound to inhibit acetyl cholinesterase at cholinergic junction of the nervous system. This study is a review of the toxicological effects of dichlorvos in a public health perspective.
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Weingartl, Hana, Stefanie Czub, John Copps, Yohannes Berhane, Deborah Middleton, Peter Marszal, Jason Gren, et al. "Invasion of the Central Nervous System in a Porcine Host by Nipah Virus." Journal of Virology 79, no. 12 (June 15, 2005): 7528–34. http://dx.doi.org/10.1128/jvi.79.12.7528-7534.2005.
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ABSTRACT Nipah virus, a newly emerged zoonotic paramyxovirus, infects a number of species. Human infections were linked to direct contact with pigs, specifically with their body fluids. Clinical signs in human cases indicated primarily involvement of the central nervous system, while in pigs the respiratory system was considered the primary virus target, with only rare involvement of the central nervous system. Eleven 5-week-old piglets were infected intranasally, orally, and ocularly with 2.5 × 105 PFU of Nipah virus per animal and euthanized between 3 and 8 days postinoculation. Nipah virus caused neurological signs in two out of eleven inoculated pigs. The rest of the pigs remained clinically healthy. Virus was detected in the respiratory system (turbinates, nasopharynx, trachea, bronchus, and lung in titers up to 105.3 PFU/g) and in the lymphoreticular system (endothelial cells of blood and lymphatic vessels, submandibular and bronchiolar lymph nodes, tonsil, and spleen with titers up to 106 PFU/g). Virus presence was confirmed in the nervous system of both sick and apparently healthy animals (cranial nerves, trigeminal ganglion, brain, and cerebrospinal fluid, with titers up to 107.7 PFU/g of tissue). Nipah virus distribution was confirmed by immunohistochemistry. The study presents novel findings indicating that Nipah virus invaded the central nervous system of the porcine host via cranial nerves as well as by crossing the blood-brain barrier after initial virus replication in the upper respiratory tract.
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Zou, D. J. "Respiratory rhythm in the isolated central nervous system of newborn opossum." Journal of Experimental Biology 197, no. 1 (December 1, 1994): 201–13. http://dx.doi.org/10.1242/jeb.197.1.201.
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1. Respiratory activity was recorded from spinal ventral roots in the isolated intact central nervous system (CNS) of newborn opossum, Monodelphis domestica. These signals occurred in synchrony with movements of the ribs and the electromyogram (EMG) recorded from the intercostal muscles during inspiration. Rhythmical activity could be recorded for more than 6 h in acute preparations. 2. The rhythm-generating region was shown to be located in the lower brain stem by perfusing different CNS regions with medium containing 20 mmoll-1 Mg2+, which blocks synaptic transmission reversibly in the opossum CNS. The conclusion that respiration was generated by neurones in the lower brain stem was further confirmed by selective ablation of part of the CNS. 3. Recordings were made from 128 neurones in the respiratory region of the lower brain stem with activity related to the respiratory rhythm. They consisted of two inspiratory groups and two expiratory groups. In the groups of inspiratory units, recordings were made from 69 early inspiratory and 38 inspiratory units. In the groups of expiratory units, recordings were made from 17 post-inspiratory and 4 expiratory units. The sites of 22 respiratory neurones were marked in 4-day-old animals by injecting Pontamine Sky Blue. These neurones were distributed from 175 microns anterior to 525 microns posterior to the obex, from 225 to 450 microns lateral to the midline and from 175 to 425 microns deep to the ventral surface of the brain stem. 4. The respiratory rhythm recorded in the isolated CNS was influenced by pH and neurotransmitters. The respiratory rate decreased by about 26% at high pH (7.7) and increased by about 33% at low pH (7.1). Bath application of noradrenaline (30-100 mumol l-1) decreased the respiratory rate and increased the amplitude of the rhythmic bursts significantly. All these effects were reversible. 5. The results presented here indicate that the isolated intact CNS of newborn opossum offers advantages for exploring mechanisms responsible for generating the respiratory rhythm.
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RAMIREZ, J. M., and K. G. PEARSON. "Alteration of the Respiratory System at the Onset of Locust Flight: I. Abdominal Pumping." Journal of Experimental Biology 142, no. 1 (March 1, 1989): 401–24. http://dx.doi.org/10.1242/jeb.142.1.401.
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The respiratory behaviour of Locusta migratoria is altered at the onset of flight. The neuronal processes and some of the mechanisms underlying these alterations were studied by using intracellular recording and staining techniques. It has previously been reported that abdominal pumping ceases for the first seconds of flight. Our data indicate that this phenomenon is not due to inhibition of the respiratory system, since most interneurones and some motoneurones maintain a respiratory rhythm during the onset of flight activity. Likely explanations for the cessation of the abdominal pumping are: (1) increased stiffness of the abdomen due to maintained activation of abdominal muscles and (2) decreased rhythmic modulation in abdominal motor units due to tonic excitatory input. Two major changes occur in the respiratory system at the onset of flight: (1) the rhythm is reset by an activation of inspiratory and inactivation of expiratory neurones, and (2) the respiratory rate is increased. The increase in the respiratory rate at the onset of flight is in part due to an activation of inspiratory interneurones which are capable of accelerating the respiratory rhythm. The changes in the respiratory system coinciding with the initiation of flight suggest a feedforward mechanism linking both behaviours. Tonic interneurones, involved in the initiation of flight and influencing respiration, might be involved in linking respiration and flight. At flight onset, one group of these simultaneously disinhibited respiration and flight and thus contributed both to an increase in the respiratory rate and to an activation of the flight system. Another group evoked flight and had variable effects on respiration. One tonic interneurone had a depressing effect on the respiratory rate. We conclude that respiration is centrally linked to flight in part by the same interneurones controlling the initiation of flight. The existence of such a feedforward mechanism in the locust resembles the situation found in vertebrates, where locomotory and respiratory behaviour can be driven from the same brainstem region.
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Zielecki, F., M. Weber, M. Eickmann, L. Spiegelberg, A. M. Zaki, M. Matrosovich, S. Becker, and F. Weber. "Human Cell Tropism and Innate Immune System Interactions of Human Respiratory Coronavirus EMC Compared to Those of Severe Acute Respiratory Syndrome Coronavirus." Journal of Virology 87, no. 9 (February 28, 2013): 5300–5304. http://dx.doi.org/10.1128/jvi.03496-12.
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Shil, SK, BC Das, M. Uddin, ML Rahman, and MA Quasem. "Anatomy of digestive and respiratory system of Indian grey mongoose (Herpestes edwardsii)." University Journal of Zoology, Rajshahi University 31 (June 23, 2013): 83–84. http://dx.doi.org/10.3329/ujzru.v31i0.15438.
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MacFarlane, P. M., P. B. Frappell, and J. P. Mortola. "Mechanics of the respiratory system in the newborn tammar wallaby." Journal of Experimental Biology 205, no. 4 (February 15, 2002): 533–38. http://dx.doi.org/10.1242/jeb.205.4.533.
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SUMMARY We investigated whether the mechanical properties of the respiratory system represent a major constraint to spontaneous breathing in the newborn tammar wallaby Macropus eugenii, which is born after a very short gestation (approximately 28 days, birth mass approximately 380 mg). The rate of oxygen consumption (V̇O2) through the skin was approximately 33 % of the total V̇O2 at day 1 and approximately 14 % at day 6. The mass-specific resting minute ventilation (V̇e) and the ventilatory equivalent (V̇e/V̇O2) were approximately the same at the two ages, with a breathing pattern significantly deeper and slower at day 1. The mass-specific compliance of the respiratory system (Crs) did not differ significantly between the two age groups and was close to the values predicted from measurements in eutherian newborns. Mass-specific respiratory system resistance (Rrs) at day 1 was higher than at day 6, and also higher than in eutherian newborns. Chest distortion, quantified as the degree of abdominal motion during spontaneous breathing compared with that required to inflate the lungs passively, at day 1 was very large, whereas it was modest at day 6. We conclude that, in the tammar wallaby at birth, the high resistance of the respiratory system and the distortion of the chest wall greatly reduce the mechanical efficiency of breathing. At this age, gas exchange through the skin is therefore an important complement to pulmonary ventilation.
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V, M, C, W, and D. "Turning the World Upside-Down in Cellulose for Improved Culturing and Imaging of Respiratory Challenges within a Human 3D Model." Cells 8, no. 10 (October 21, 2019): 1292. http://dx.doi.org/10.3390/cells8101292.
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Polarized growth of human-derived respiratory epithelial cells on hydrogel-coated filters offers big advantages concerning detailed experiments with respect to drug screening or host pathogen interactions. Different microscopic approaches, such as confocal analyses and high content screening, help to examine such 3D respiratory samples, resulting in high-resolution pictures and enabling quantitative analyses of high cell numbers. A major problem employing these techniques relates to single-use instead of multiple-use of Transwell filters and difficulties in the digestion of collagen if subsequent analyses are needed. Up to date, cells are seeded in collagen-based matrices to the inner field of Transwell inserts, which makes it impossible to image due to the design of the inserts and hard to perform other analyses since digestion of the collagen matrix also affects Transwell grown cells. To overcome these problems, we optimized culturing conditions for monitoring cell differentiation or repeated dose experiments over a long time period. For this, cells are seeded upside-down to the bottom side of filters within an animal-free cellulose hydrogel. These cells were then grown inverted under static conditions and were differentiated in air-liquid interphase (ALI). Full differentiation of goblet (Normal Human Bronchial Epithelial (NHBE))/Club (small airway epithelia (SAE)) cells and ciliated cells was detected after 12 days in ALI. Inverted cell cultures could then be used for ‘follow-up’ live cell imaging experiments, as well as, flow-cytometric analyses due to easy digestion of the cellulose compared to classical collagen matrices. Additionally, this culture technique also enables easy addition of immune cells, such as dendritic cells (DCs), macrophages, neutrophils, T or B cells alone or in combination, to the inner field of the Transwell to monitor immune cell behavior after repeated respiratory challenge. Our detailed protocol offers the possibility of culturing human primary polarized cells into a fully differentiated, thick epithelium without any animal components over >700 days. Furthermore, this animal-free, inverted system allows investigation of the same inserts, because the complete Transwell can be readily transferred to glass-bottom dishes for live cell imaging analyses and then returned to its original plate for further cultivation.
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MacLellan, Kirsty, Colin Loney, R. Paul Yeo, and David Bhella. "The 24-Angstrom Structure of Respiratory Syncytial Virus Nucleocapsid Protein-RNA Decameric Rings." Journal of Virology 81, no. 17 (June 13, 2007): 9519–24. http://dx.doi.org/10.1128/jvi.00526-07.
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ABSTRACT Respiratory syncytial virus (RSV), a nonsegmented, negative-sense RNA-containing virus, is a common cause of lower respiratory tract disease. Expression of RSV nucleocapsid protein (N) in insect cells using the baculovirus expression system leads to the formation of N-RNA complexes that are morphologically indistinguishable from viral nucleocapsids. When imaged in an electron microscope, three distinct types of structures were observed: tightly wound short-pitch helices, highly extended helices, and rings. Negative stain images of N-RNA rings were used to calculate a three-dimensional reconstruction at 24 Å resolution, revealing features similar to those observed in nucleocapsids from other viruses of the order Mononegavirales. The reconstructed N-RNA rings comprise 10 N monomers and have an external radius of 83 Å and an internal radius of 40 Å. Comparison of this structure with crystallographic data from rabies virus and vesicular stomatitis virus N-RNA rings reveals striking morphological similarities.
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Williams, B. "Adaptations to Endoparasitism in the Larval Integument and Respiratory System of the Flea Uropsylla-Tasmanica Rothschild (Siphonaptera, Pygiopsyllidae)." Australian Journal of Zoology 39, no. 1 (1991): 77. http://dx.doi.org/10.1071/zo9910077.
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An histological study of flea larvae was carried out in order to compare free-living larvae with the unique endoparasitic larva of Uropsylla tasmanica, a species found on marsupial cats in Tasmania and Victoria, Australia. The free-living species examined were the cat flea Ctenocephalides felis, and Odontopsyllus quirosi. Body shape in U. tasmanica is adapted to endoparasitism; the anterior segments are greatly expanded and the abdominal segments are reduced from ten to eight. This reduction brings the last abdominal spiracle (8), to the posterior end of the larva, allowing better access to oxygen from the atmosphere. Possible evolutionary steps in this modification are suggested. Third-instar U. tasmanica have non-functional prothoracic spiracles and the metathoracic spiracles are either non-functional or absent. All three instars of C. felis are peripneustic, and third-instar O. quirosi larvae are holopneustic. Contrary to previous ideas, the respiratory systems of flea larvae do not provide exceptions to the generalisations that in holometabolous insect larvae the metathoracic spiracle is nearly always non-functional, and, that functional and non-functional spiracles coexist in these larvae. Features in U. tasmanica convergent with those of endoparasitic, saprophagous and aquatic fly larvae are discussed.
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Ren, Ai-Xia, You-Hua Xie, Yu-Ying Kong, Guan-Zhen Yang, Yao-Zhou Zhang, Yuan Wang, and Xiang-Fu Wu. "Expression, Purification and Sublocalization of SARS-CoV Nucleocapsid Protein in Insect Cells." Acta Biochimica et Biophysica Sinica 36, no. 11 (November 1, 2004): 754–58. http://dx.doi.org/10.1093/abbs/36.11.754.
Full textAbstract:
Abstract The causative agent of severe acute respiratory syndrome (SARS) is a previously unidentified coronavirus, SARS-CoV. The nucleocapsid (N) protein of SARS-CoV is a major viral protein recognized by acute and early convalescent sera from SARS patients. To facilitate the studies on the function and structure of the N protein, this report describe the expression and purification of recombinant SARS-CoV N protein using the baculovirus expression system. Recombinant hexa-histidine-tagged N protein with a molecular mass of 47 kD was produced in insect cells. Recombinant N protein was purified to near homogeneity by Ni2+-NTA affinity chromatography. In addition, we examined the subcellular localization of the N protein by confocal microscopy in Trichoplusia ni BT1 Tn 5B1–4 cells infected with recombinant baculovirus. The N protein was found localized in the cytoplasm as well as in the nucleolus. The purified recombinant N protein can be used in further functional study of SARS-CoV.
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Turner, D. L. "Cardiovascular and respiratory control mechanisms during exercise: an integrated view." Journal of Experimental Biology 160, no. 1 (October 1, 1991): 309–40. http://dx.doi.org/10.1242/jeb.160.1.309.
Full textAbstract:
Exercise can impose an immense stress upon many physiological systems throughout the body. In order that exercise performance may be optimally maintained, it is essential that a profound and complex series of responses is coordinated and controlled. The primary site for coordination is the central nervous system, whereas control mechanisms (both feedback loops and feedforward activation) involve complex sensory information, often in the form of neural coding but also in the form of blood-borne chemical signals, a number of levels of peripheral and central integration and, finally, the efferent branches of the nervous system coursing via sympathetic and parasympathetic nerves to target sites of action. The neurohumoral control of the cardiorespiratory responses to exercise has received intense attention for over two decades and some particularly important steps forward in its understanding have occurred within the last 10 years. The initial fast increase (phase 1) in cardiovascular and ventilatory flow parameters are brought about by neurally mediated muscle mechanoreceptor feedback reflexes and a feedforward ‘central motor command’. The blood pressure operating point is also raised by a combination of these two neural mechanisms. Fine control of the matching of cardiac output to ventilation may occur by means of a feedforward ventilatory control of cardiac origin. During the slower phase of adjustment (phase 2), the neurally mediated mechanisms are augmented by a cohort of humorally mediated feedback reflexes involving muscle and vascular chemoreceptors as well as being supported by central neural reverberation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Inoue, T., M. Takasaki, K. Lukowiak, and N. Syed. "Inhibition of the respiratory pattern-generating neurons by an identified whole-body withdrawal interneuron of Lymnaea stagnalis." Journal of Experimental Biology 199, no. 9 (September 1, 1996): 1887–98. http://dx.doi.org/10.1242/jeb.199.9.1887.
Full textAbstract:
Respiration and the whole-body withdrawal are two incompatible behaviors in the freshwater snail Lymnaea stagnalis. Whole-body withdrawal behavior is believed to be higher on the behavioral hierarchy than respiratory behavior. A central pattern generator (CPG) underlies respiratory behavior; whole-body withdrawal is mediated by a network of electrically coupled neurons. In this study, we provide evidence that the behavioral hierarchy between the whole-body withdrawal and the respiratory behaviors is established at the interneuronal level. We demonstrate that an identified whole-body withdrawal interneuron inhibits both muscular and neuronal components of the respiratory behavior in Lymnaea stagnalis. A pair of identified, electrically coupled interneurons, termed left and right pedal dorsal 11 (L/RPeD11), coordinates the whole-body withdrawal behavior in Lymnaea stagnalis. In the present study, RPeD11 inhibited spontaneously occurring respiratory CPG activity in isolated brain preparations. In addition, electrical stimulation of RPeD11 in a semi-intact preparation also inhibited respiratory CPG interneuron RPeD1. The synaptic connections between RPeD11 and the respiratory CPG neurons RPeD1 and visceral dorsal 4 (VD4) persisted in the presence of high-Ca2+/high-Mg2+ saline, suggesting the possibility that they may be monosynaptic. In a semi-intact preparation (lung­mantle, pneumostome and central nervous system), electrical stimulation of RPeD11 induced pneumostome and columellar muscle contractions while inhibiting the activity of RPeD1. Moreover, mechanical stimulation of the respiratory orifice, the pneumostome, excited RPeD11, while its effects on the respiratory CPG neuron (RPeD1) were inhibitory. To determine the monosynaptic nature of connections between RPeD11 and the respiratory CPG neurons in the intact nervous system, we constructed these synapses in culture. RPeD11 and individual respiratory interneurons were isolated from their respective ganglia and co-cultured under conditions that support neurite outgrowth. Following neuritic overlap, RPeD11 was found to establish inhibitory synapses with the respiratory interneurons, supporting the hypothesis that these synaptic connections are likely to be monosynaptic in the intact central nervous system.